ALBERT

Description: 〈p〉Publication date: 5 January 2020〈/p〉 〈p〉〈b〉Source:〈/b〉 Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 224〈/p〉 〈p〉Author(s): Hayam M. Lotfy, Sarah S. Saleh, Christine M. El-Maraghy〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉An analytical investigation was carried out to study the treatment and amplification of the spectral signals produced by critical concentrations with high accuracy and precision using two advanced approaches. The factorized-spectrum approach was applied through two novel methods which were: absorptivity centering technique via both: factorized zero order absorption spectrum (ACT-FSD〈sup〉0〈/sup〉〈sub〉∆A〈/sub〉) and factorized ratio spectrum (ACT-FSR〈sub〉∆P〈/sub〉). The proposed methods were found to be linear in the ranges of (15–100 μg/mL) and (3–40 μg/mL) for ASP and MTO, respectively. Those methods were compared to the methods following the geometrical standard addition approach: ratio H-point standard addition method (RHPSAM) and geometrical induced amplitude modulation (GIAM). The approaches were applied for the determination of the minor component metoclopramide in its mixture with the major component aspirin in the challengeable ratio of (1,90) respectively in a white multicomponent system. The results obtained from the proposed approaches were statistically compared with each other. The methods were validated according to ICH guidelines where the results were found to be within the acceptable limits. The methods were found to be accurate and reliable for the determination of metoclopramide critical concentration besides aspirin concentration. The results of single factor ANOVA analysis indicated that there is no significant difference among the developed methods. These methods provided simple resolution of this binary combination from synthetic mixtures and pharmaceutical preparation and can be conveniently adopted for routine quality control analysis.〈/p〉〈/div〉 〈/div〉 〈div xml:lang="en"〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S1386142519307292-ga1.jpg" width="325" alt="Unlabelled Image" title="Unlabelled Image"〉〈/figure〉〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 5 December 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 223〈/p〉 〈p〉Author(s): Rui Zhang, Yun Liu, Lin Kong, Xian-Yun Xu〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉In this study, a two photon absorbing (TPA) material consisting silver nanoparticles and triphenylamine-thiol derivative (TBS) has been prepared through interfacial coordination effect according to soft-hard-acid-base principle. The interfacial structure and morphology of the hybrid are researched in detail. Linear and nonlinear optical properties of the hybrid are studied. Upon interfacial coordination, the hybrid shows red-shifted UV–Vis absorption, causing from enhanced electronic drawing strength due to existence of Ag atom. The results also indicate that the surface Plasmon resonance (SPR) effect of Ag nanoparticles (~6 nm) brings about enhancement in single photon fluorescence emission and two photon absorption. Compared with free TBS, Ag-TBS hybrids show higher TPA cross-section (δ), which is 8784 GM for TBS and up to 103876 GM for Ag-TBS hybrid, showing ~12 fold increase. Due to excellent TPA property, the hybrids have good application in the field of optical power limiting and its limiting threshold is 0.49 J/cm〈sup〉−2〈/sup〉. This type of interfacial coordination induced hybrid provides a promising strategy to regulate linear optical properties and optimize nonlinear performance.〈/p〉〈/div〉 〈/div〉 〈div xml:lang="en"〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉A thiol-Ag nanohybrid has been prepared through interfacial coordination effect and self-assembly process to optimize the TPA performance.〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S1386142519307280-ga1.jpg" width="500" alt="Unlabelled Image" title="Unlabelled Image"〉〈/figure〉〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 5 December 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 223〈/p〉 〈p〉Author(s): Qiujuan Ma, Chunyan Wang, Yu Bai, Junhong Xu, Juan Zhang, Zhengkai Li, Xiaoyu Guo〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Hypochlorous acid (HClO) is an important reactive oxygen species (ROS) and plays a significant role in living organisms. Highly selective and lysosome-targetable probes for sensing hypochlorous acid are rare. In this article, we designed and prepared a new lysosome-targeting and ratiometric fluorescent probe for monitoring the levels of hypochlorous acid. 4-Aminonaphthalimide was chosen as the fluorescent group and (2-aminoethyl) thiourea group was used as a specific recognition group for HClO. A morpholine unit was employed as a lysosome-targeting group. In the absence of HClO the probe underwent intramolecular charge transfer (ICT) and showed a green emission. When excess HClO is present, the ICT process was interrupted which caused a 57 nm blue-shift of fluorescence emission from 533 nm to 476 nm. The ratiometric fluorescent probe showed outstanding selectivity toward HClO over other various bioactive species. Furthermore, the ratiometric fluorescent probe exhibited rapid response time and ability of working in a wide pH range. The linear response of I〈sub〉476nm〈/sub〉/I〈sub〉533nm〈/sub〉 toward HClO was obtained in a concentration range of HClO from 1.0 × 10〈sup〉−6〈/sup〉 to 1.0 × 10〈sup〉−4〈/sup〉 mol·L〈sup〉−1〈/sup〉. The detection limit was estimated to be 8.0 × 10〈sup〉−7〈/sup〉 mol·L〈sup〉−1〈/sup〉 for HClO. Moreover, the probe showed a perfect lysosome-targeting ability, and has been successfully used to the confocal imaging of HClO in lysosomes of HepG2 cells with little cell toxicity. All of such good properties illustrated that it could be applied to determine HClO at lysosomes in living cells.〈/p〉〈/div〉 〈/div〉 〈div xml:lang="en"〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S1386142519307243-ga1.jpg" width="158" alt="Unlabelled Image" title="Unlabelled Image"〉〈/figure〉〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 5 January 2020〈/p〉 〈p〉〈b〉Source:〈/b〉 Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 224〈/p〉 〈p〉Author(s): Markéta Paloncýová, Gustav Aniander, Emma Larsson, Stefan Knippenberg〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Visualization of membrane domains like lipid rafts in natural or artificial membranes is a crucial task for cell biology. For this purpose, fluorescence microscopy is often used. Since fluorescing probes in lipid membranes partition specifically in e.g. local liquid disordered or liquid ordered environments, the consequent changes in their orientation and location are both theoretically and experimentally of interest. Here we focused on a liquid disordered membrane phase and performed molecular dynamics (MD) simulations of the indocarbocyanine DiD probes by varying the length of the attached alkyl tails and also the length of the cyanine backbone. From the probed compounds in a DOPC lipid bilayer at ambient temperature, a varying orientation of the transition dipole moment was observed, which is crucial for fluorescence microscopy and which, through photoselection, was found to be surprisingly more effective for asymmetric probes than for the symmetric ones. Furthermore, we observed that the orientation of the probes was dependent on the tail length; with the methyls or propyls attached, DiD oriented with its tails facing the water, contrary to the ones with longer tails. With advanced hybrid QM/MM calculations we show that the different local environment for differently oriented probes affected the one-photon absorption spectra, that was blue-shifted for the short-tailed DiD with respect to the DiDs with longer tails. We show here that the presented probes can be successfully used for fluorescence microscopy and we believe that the described properties bring further insight for the experimental use of these probes.〈/p〉〈/div〉 〈/div〉 〈div xml:lang="en"〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S138614251930719X-ga1.jpg" width="417" alt="Unlabelled Image" title="Unlabelled Image"〉〈/figure〉〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 5 December 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 223〈/p〉 〈p〉Author(s): Sheng Zhou, Ningwu Liu, Chongyang Shen, Lei Zhang, Tianbo He, Benli Yu, Jingsong Li〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉A compact high-resolution spectroscopic sensor using a thermoelectrically (TE) cooled continuous-wave (CW) room temperature (RT) quantum cascade laser (QCL) was demonstrated for simultaneous measurements of exhaled carbon monoxide (CO) and nitrous oxide (N〈sub〉2〈/sub〉O). The sampling pressure was optimized to improve the sensitivity, the optimal pressure was determined to be 150 mbar based on an optical density analysis of simulated and measured absorption spectra. An adaptive Kalman filtering algorithm based on back-propagation (BP) neural network was developed and proposed for real-time exhaled breath analysis in order to perform fast and high precision on-line measurements. The detection limits (1σ) of 1.14 ppb and 1.12 ppb were experimentally achieved for CO and N〈sub〉2〈/sub〉O detection, respectively. Typical concentrations of exhaled CO and N〈sub〉2〈/sub〉O from smokers and non-smokers were analyzed. The experimental results indicated that the state-of-the-art CW-QCL based sensor has a great potential for non-invasive, on-line identification and quantification of biomarkers in human breath.〈/p〉〈/div〉 〈/div〉 〈div xml:lang="en"〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S138614251930722X-ga1.jpg" width="500" alt="Unlabelled Image" title="Unlabelled Image"〉〈/figure〉〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 5 December 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 223〈/p〉 〈p〉Author(s): Susan Sadeghi, Samieh Olieaei〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The new ionic liquid capped CdS quantum dots (IL-CdS QDs) as a fluorescent probe was successfully synthesized by a hydrothermal method in a one step process and used for the facile and sensitive determination of florfenicol (FLF) in aqueous media. The new ionic liquid 3-(2-[(5-amino-1,3,4-thiadiazol-2-yl)thio]ethyl)-1-methyl-1H-imidazol-3-ium chloride (IL) was synthesized by introducing 5-amino-1,3,4-thiadiazole-2-thiol as a ligand onto the alkyl chain of the 1-chloroethyl-3-methylimidazolium chloride ILs. This task specific ionic liquid reagent was used for the capping of CdS QDs which played the role of recognition element of FLF. The IL-CdS QDs were characterized by Ultra Violet-Visible absorption -spectroscopy (UV–Vis absorption spectroscopy), Fourier transform infrared (FT-IR) spectroscopy, X-ray diffraction (XRD), and transmission electron microscopy (TEM). Quenching of fluorescence intensity of the IL-CdS QDs was in proportion to the addition of FLF concentration. Under the optimum conditions, the fluorescence intensity ratio of IL-CdS QDs in the presence and absence of FLF versus FLF concentrations gave a linear response according to the Stern-Volmer equation from 0.1 to 20 μg mL〈sup〉−1〈/sup〉 (0.3 to 56 μmol L〈sup〉−1〈/sup〉) with a limit of detection 0.035 μg mL〈sup〉−1〈/sup〉 (0.098 μmol L〈sup〉−1〈/sup〉). The developed method was applied to the determination of FLF in fish and chicken meats with satisfactory results. This method revealed some advantages such as high sensitivity, precision and wide linear range to FLF. The proposed method can be utilized for rapid screening the quality of meat products.〈/p〉〈/div〉 〈/div〉 〈div xml:lang="en"〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S1386142519307395-ga1.jpg" width="382" alt="Unlabelled Image" title="Unlabelled Image"〉〈/figure〉〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 5 December 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 223〈/p〉 〈p〉Author(s): Masoomeh Shaghaghi, Gholamreza Dehghan, Samaneh Rashtbari, Nader Sheibani, Azam Aghamohammadi〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The binding of sitagliptin (SIT), an anti-diabetic drug, to human and bovine serum albumin (HSA and BSA; main serum transport proteins) was investigated using various spectroscopic and molecular docking techniques. The fluorescence data demonstrated that SIT quenched inherent fluorescence of these proteins through the formation of SIT-HSA/BSA complexes. The number of binding sites was obtained (~1) and binding constant (K〈sub〉b〈/sub〉) and effective quenching constant (K〈sub〉a〈/sub〉) were calculated as 10〈sup〉4〈/sup〉 for both systems. Based on thermodynamic parameters, the van der Waals forces and hydrogen bonding were the most important forces in the interactions between HSA/BSA and SIT, and the complex formation processes were spontaneous. The results of UV–vis absorption and FT-IR spectroscopic revealed that SIT induces small conformational changes in the structure of the proteins (HSA/BSA). The synchronous fluorescence (SF) spectroscopy demonstrated that the binding of SIT with HSA/BSA had no effect on the polarity around Trp and Tyr residues. The CD spectra showed changes in the secondary and tertiary structures of both proteins with a decrease in α-helices contents and an increase in β-turn structures. The molecular docking and spectroscopic data verified the binding mechanisms between SIT and HSA/BSA, and revealed that SIT completely fits into the hydrophobic cavity between domain II and domain III of these proteins.〈/p〉〈/div〉 〈/div〉 〈div xml:lang="en"〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S1386142519306766-ga1.jpg" width="348" alt="Unlabelled Image" title="Unlabelled Image"〉〈/figure〉〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 5 December 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 223〈/p〉 〈p〉Author(s): Praveen Mishra, Badekai Ramachandra Bhat〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉We report a facile one step in-situ synthesis of amino-functionalized graphene dots. These quantum dots were employed for the detection of glucose in both standard aqueous solutions and commercially available fruit juice to assess its practicability. The characterization of the quantum dots revealed that they were decorated with amine functionality. Additionally, the interaction between glucose and amine functionalized graphene quantum dots gave enhancement in the UV–vis absorption and photoluminescence (PL) due to aggregation of quantum dots via glucose link. Therefore, the quantum dots were able to detect the concentration of glucose in solution exhibiting linearity from 0.1 to 10 mM and 50–500 mM with a sensitivity transition from 10 mM to 50 mM. The limit of detection for the determination of glucose was found to be 10 μM. This determination was agreed from both UV–Vis absorption and PL spectroscopy. However, the PL emission method of determination was most suited with its very high accuracy of 98.04 ± 1.96% and 97.33 ± 2.67% for the linear range of glucose concentration within 0.1–10 mM and 50–500 mM, respectively. The PL enhancement was highly selective towards glucose in mixture of other form of sugars making it suitable for determining glucose in food samples.〈/p〉〈/div〉 〈/div〉 〈div xml:lang="en"〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S1386142519307152-ga1.jpg" width="301" alt="Unlabelled Image" title="Unlabelled Image"〉〈/figure〉〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 5 December 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 223〈/p〉 〈p〉Author(s): Saman Khan, Atif Zafar, Imrana Naseem〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉HSA is an important plasma protein responsible for transport of drug molecules. Coumarin derivatives play critical role as anticancer, antidiabetic and antiparkinson agents. In our lab we have synthesized coumarin-based pharmacophore, di(2-picolyl)amine-3(bromoacetyl) coumarin (ligand-L) endowed with anticancer activity. Anticancer agents binding mode of HSA provides valuable pharmacological information and is a structural guidance in synthesizing new drugs with greater efficacy. Thus, binding mechanism of ligand-L with HSA was explored using spectroscopic and molecular docking techniques. UV–Vis spectroscopy demonstrates hyperchromism in the absorbance spectra of HSA on addition of ligand-L suggesting interaction of ligand-L with HSA. Fluorescence spectroscopy indicates quenching in the fluorescence of HSA in the presence of ligand-L confirming the complex formation and this binding follows static mechanism. Steady state fluorescence spectroscopy revealed high binding affinity between ligand-L and HSA with a 1:1 stoichiometry. Thermodynamic parameters obtained by ITC suggest that the interaction between ligand-L and HSA is mainly driven by van der Waals forces and hydrogen bonds, and the negative value of ΔG is an indication of spontaneous binding process. Competitive binding and molecular docking experiments showed that the binding site of ligand-L mainly resides in sub-domain IIA of HSA. CD experiments revealed no significant conformational changes in the secondary structure of HSA on binding of ligand-L. We also found that esterase-like activity of HSA was not affected by ligand-L. In conclusion, this study demonstrates binding mechanism of ligand-L with HSA, and the binding did not induce conformational changes in HSA. This study is likely to provide better understanding of transport and delivery of ligand-L via HSA. Overall, it will provide insights into pharmacokinetic properties of ligand-L and designing new ligand-L based derivatives with greater efficacy.〈/p〉〈/div〉 〈/div〉 〈div xml:lang="en"〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S1386142519307206-ga1.jpg" width="301" alt="Unlabelled Image" title="Unlabelled Image"〉〈/figure〉〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 15 January 2020〈/p〉 〈p〉〈b〉Source:〈/b〉 Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 225〈/p〉 〈p〉Author(s): Xiaotong Zhang, Yurong Shi, Lei Cai, Yong Zhou, Chuan-Kui Wang, Lili Lin〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉As the third-generation organic electroluminescent materials, thermally activated delayed fluorescence (TADF) molecules have become the research focus recently. Significant solvent effect on TADF molecules were found experimentally, while theoretical investigations are quite limited. In this work, the solvent effect on photophysical properties of DCBPy and DTCBPy are investigated with first-principles calculations. The solvent polarity has slight influence on the molecular geometries and orbitals, while it can decrease the energy gap between the first singlet excited state (S1) and first triplet excited state (T1) significantly. Both the oscillator strength and the radiation rates of S1 increase with larger solvent polarity. The large energy gap between S1 and T1 induce negligible intersystem crossing (ISC) and reverse ISC rates between them, which also indicates higher triplet excited states are involved in the up-conversion process. Our results provide valuable information about solvent influence on the light-emitting properties of TADF molecules, which could help one better understand the light-emitting mechanism of them and favor the design of TADF molecules.〈/p〉〈/div〉 〈/div〉 〈div xml:lang="en"〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S1386142519308637-ga1.jpg" width="301" alt="Unlabelled Image" title="Unlabelled Image"〉〈/figure〉〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 15 January 2020〈/p〉 〈p〉〈b〉Source:〈/b〉 Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 225〈/p〉 〈p〉Author(s): Guanhua Ren, Siqi Zong, Zhongjie Zhu, Chao Cheng, Ligang Chen, Lu Zhou, Jianbing Zhang, Liyuan Liu, Jiaguang Han, Hongwei Zhao〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉As the building blocks of proteins, amino acids serve vital metabolic functions in addition to protein synthesis and thus attract enormous interest. Here we reported the far-infrared optical properties of L-cysteine (Lcys) and its hydrochloride monohydrate (LCHM) characterized by terahertz time-domain spectroscopy. The Lcys and LCHM exhibit quite distinct characteristics in the terahertz region due to diverse collective vibrations of the molecules, which is further confirmed by the solid-state density functional theory (DFT) calculations. The presented studies indicate that the intermolecular hydrogen bonds play a critical role in the far-infrared terahertz response of Lcys and LCHM.〈/p〉〈/div〉 〈/div〉 〈div xml:lang="en"〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S1386142519308662-ga1.jpg" width="449" alt="Unlabelled Image" title="Unlabelled Image"〉〈/figure〉〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 15 January 2020〈/p〉 〈p〉〈b〉Source:〈/b〉 Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 225〈/p〉 〈p〉Author(s): Preeti Gupta, Faez Iqbal Khan, Sonam Roy, Saleha Anwar, Rashmi Dahiya, Mohammed F. Alajmi, Afzal Hussain, Md. Tabish Rehman, Dakun Lai, Md. Imtaiyaz Hassan〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Sphingosine kinase 1 (SphK1) catalyzes the conversion of sphingosine to sphingosine-1-phosphate that acts as a bioactive signalling molecule, and regulates various cellular processes including lymphocyte trafficking, angiogenesis and response to apoptotic stimuli. Abnormal expression of SphK1 has been observed in a wide range of cancers highlighting their role in tumour growth and metastasis. This enzyme also plays a critical role in metabolic and inflammatory diseases, including pulmonary fibrosis, diabetic neuropathy and Alzheimer's disease. In the present study, we have investigated the structural and conformational changes in SphK1 at varying pH using various spectroscopic techniques. Consistent results were observed with the function of SphK1 at corresponding pH values. SphK1 maintains its secondary and tertiary structure in the pH range of 7.5–10.0. However, protein aggregation was observed in the acidic pH range (4.0–6.5). At pH 2.0, the SphK1 exists in the molten-globule state. Kinase assay also shows that SphK1 activity was optimal in the pH range of 7.5–8.5. To complement 〈em〉in vitro〈/em〉 results, we have performed 100 ns molecular dynamics simulation to examine the effect of pH on the structural stability of SphK1 at molecular level. SphK1 maintains its native conformation in the alkaline pH range with some residual fluctuations detected at acidic pH. A considerable correlation was noticed between spectroscopic, enzymatic activity and MD simulation studies. pH dependent structural changes can be further implicated to understand its association with disease condition, and cellular homeostasis with respect to protein function under variable pH conditions.〈/p〉〈/div〉 〈/div〉 〈div xml:lang="en"〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S1386142519308431-ga1.jpg" width="273" alt="Unlabelled Image" title="Unlabelled Image"〉〈/figure〉〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 15 January 2020〈/p〉 〈p〉〈b〉Source:〈/b〉 Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 225〈/p〉 〈p〉Author(s): Hiba Mohamed Ameen, Sándor Kunsági-Máté, Lajos Szente, Beáta Lemli〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Sulfonamides are preventive and therapeutic agents for certain infections caused by gram-positive and gram-negative microorganisms. In this work the interactions of sulfamethazine, a representative of sulfonamide antibiotics, with two β-cyclodextrin derivatives were investigated at different pH. Results show formation of stable sulfamethazine - β-cyclodextrin complexes and reflect importance of the competition of the hydrogen bonding and electrostatic interactions. The complex geometry formed is affected by the orientation of the pH-dependent dipole moment of sulfamethazine molecule and prolonged prior the sulfamethazine molecule enters into the β-cyclodextrin's cavity. Functionalization of the β-cyclodextrin molecule doesn't affect considerably the complex stabilities, therefore the native β-cyclodextrin molecule looks the simplest and most effective inclusion host to design selective and sensitive tool for sulfamethazine sensing.〈/p〉〈/div〉 〈/div〉 〈div xml:lang="en"〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S1386142519308650-ga1.jpg" width="235" alt="Unlabelled Image" title="Unlabelled Image"〉〈/figure〉〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 15 January 2020〈/p〉 〈p〉〈b〉Source:〈/b〉 Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 225〈/p〉 〈p〉Author(s): Adele Bosi, Alessandro Ciccola, Ilaria Serafini, Marcella Guiso, Francesca Ripanti, Paolo Postorino, Roberta Curini, Armandodoriano Bianco〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉 〈p〉Paints used in street art are modern materials subjected to degradation processes, which are very complex and difficult to predict without taking into account of several factors. This study investigates three outdoor murals in Lazio, – namely “graffiti”, a word now used to indicate a spontaneous street art tendency consisting in images and writings realized by spray paints in public spaces to provoke passersby -with the aim to discover materials application techniques and chemical composition and figure out whether alteration phenomena occurred.〈/p〉 〈p〉Twenty-two samples were collected, and their stratigraphy was studied by optical microscopy. Fourier Transformed Infrared spectroscopy was used to identify binders and their degradation products in paints and preparatory layers, while for characterization of organic pigments used in all different stratigraphy layers of samples micro-Raman spectroscopy analyses was carried out. Furthermore, micro-Raman spectroscopy allowed to study an unusual patina formed on the surface of a pink paint.〈/p〉 〈p〉This information is useful for artists as well as for conservators, who must face numerous issues related to the preservation of this modern and labile kind of artistic expression, very fashionable nowadays but often created without care for materials duration. Conservation issues were also deepened by interviews with several contemporary mural authors.〈/p〉 〈p〉Artists underlined how contemporary murals are a very heterogeneous means of expression. Different cultural tendencies coexisting result in different attitude towards conservation.〈/p〉 〈/div〉 〈/div〉 〈div xml:lang="en"〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S1386142519308649-ga1.jpg" width="354" alt="Unlabelled Image" title="Unlabelled Image"〉〈/figure〉〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 15 January 2020〈/p〉 〈p〉〈b〉Source:〈/b〉 Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 225〈/p〉 〈p〉Author(s): Bahareh Jamshidi〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The feasibility of utilizing near-infrared (NIR) spectroscopy has been recently assessed for rapid and non-destructive detection of internal insect infestation in some fruits. Based on the findings, this technology can be used for on/in-line inspection of the fruits in terms of insect infestation if suitable instrument is selected for accurate spectral measurements and system development. The spectral range and optical measurement mode are two of the most important factors which can affect the accuracy of the spectral measurements and detection models. The aim of this study is meta-analysis of these factors' effects on the ability of NIR-based spectroscopy for non-destructive detection of hidden insect infestation in fruits. Eight studies (65 observations) were extracted based on the criteria of this study. Overall, utilizing NIR-based spectroscopy led to 13.98% error (95% CI = 10.69–17.27%) for non-destructive detection of hidden insect infestation in fruits. Spectral ranges of Vis/SWNIR (above 300 up to 1100 nm), NIR (above 780 up to 2500 nm), and Vis/NIR (above 300 up to 2500 nm) showed errors of 21.71% (95% CI = 16.56–26.86%), 13.30% (95% CI = 5.24–21.36%), and 13.65% (95% CI = 5.9–21.4%), respectively. It was noted that wavelengths above 1100 nm (NIR region) are more useful to detect insect infestation in fruit. Results also indicated that optical measurement modes of interactance, reflectance, and transmittance had errors of 6.66% (95% CI = 4.18–9.14%), 15.73% (95% CI = 10.99–20.47%), and 16.04% (95% CI = 7.26–24.82%), respectively. This meta-analysis suggests that utilizing interactance mode for spectra measurement in NIR-based spectroscopy can increase the accuracy of discrimination of insect infested fruits especially when the spectral range of the spectrometer is Vis/SWNIR. Moreover, it should be selected a spectrometer with the wavelength range of NIR or Vis/NIR when using reflectance or transmittance mode is necessary for developing an in/on-line system to detect insect infestation in fruits.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 15 January 2020〈/p〉 〈p〉〈b〉Source:〈/b〉 Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 225〈/p〉 〈p〉Author(s): M. Bala Divya, Lalitha Guruprasad〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉An ionic liquid (IL) is a salt in which the ions are poorly coordinated, resulting in these solvents being liquid below 100 °C or even at room temperature. ILs generally consist of large sized anions and cations, have certain unique advantageous properties and hence are considered as ‘green solvents’. Thermal stability of the α/β-serine hydrolase (SH) domain in PE1 and PE2 proteins of 〈em〉Mycobacterium tuberculosis〈/em〉 (〈em〉M.tb〈/em〉) possessing esterase activity was studied in the presence of aprotic ILs consisting of imidazolium cations and anions. Addition of ILs to an aqueous solution of proteins prevented their unfolding and aggregation at higher temperatures. The thermal denaturation curve of proteins with ILs shifted to higher temperatures compared to the absence of ILs from CD spectra. The remaining activities of PE1/PE2 proteins with 1.4 M [EMIM][BF〈sub〉4〈/sub〉], [EMIM][Cl], [BMIM][BF〈sub〉4〈/sub〉] and [BMIM][Cl] exhibited 100%/100%, 58.96%/58.84%, 78.92%/78.94% and 54.63%/54.92% greater activities, respectively after the heat treatment at 30 °C for 35 min. We conclude that the remaining activities of both proteins are sufficiently maintained after the heat treatment and this depends upon the nature, concentration of ILs, and the thermal incubation time. Specifically, [EMIM][BF〈sub〉4〈/sub〉] and [BMIM][BF〈sub〉4〈/sub〉] exhibit higher thermal stabilization compared to [EMIM][Cl] and [BMIM][Cl].〈/p〉〈/div〉 〈/div〉 〈div xml:lang="en"〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S1386142519308674-ga1.jpg" width="424" alt="Unlabelled Image" title="Unlabelled Image"〉〈/figure〉〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: Available online 19 August 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy〈/p〉 〈p〉Author(s): Jie Zhang, Suoping Peng, Yucong Wei, Shaohui Zheng〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Non-fullerene acceptor based organic bulk heterojunction solar cells have been a hot topic because their power conversion efficiencies have been up to 16.35%. Functionalized 6,13‑bis (trimethylsilyl alkynyl) pentacenes with strong electron withdrawing groups, which can be easily modified to improve charge transport properties and film morphology, seem to be promising soluble non-fullerene pentacene-based organic acceptors. But how the substitutions of electron withdrawing groups influence their electronic structures, then change the absorption spectra and power conversion efficiencies, is still not clear. In this paper, we utilize density functional theory and time-dependent density functional theory to study the effects of substitutions of different electron withdrawing groups (〈img src="https://sdfestaticassets-eu-west-1.sciencedirectassets.com/shared-assets/16/entities/sbnd"〉CN, 〈img src="https://sdfestaticassets-eu-west-1.sciencedirectassets.com/shared-assets/16/entities/sbnd"〉CF〈sub〉3〈/sub〉, 〈img src="https://sdfestaticassets-eu-west-1.sciencedirectassets.com/shared-assets/16/entities/sbnd"〉NO〈sub〉2〈/sub〉) and different positions of these groups in 6,13‑bis (trimethylsilyl alkyl) pentacene molecule on their physical and optical properties. We find that the experimental power conversion efficiencies are positively/negatively correlated with calculated dipole moments/exciton binding energies of these functionalized molecules. The computed results indicate that the molecules substituted with CN group have much larger dipole moment than the others. For the same electron withdrawing group, the dipole moment at the R2 position is generally larger than that at the R1 position. Furthermore, we find that the calculated exciton binding energy of these molecules functionalized at the R2 position is lower than that at the R1 position. In addition, the result of absorption spectra confirm that these functionalized 6,13‑bis (trimethylsilyl alkynyl) pentacenes have stronger absorption strength than C60 in the both visible and the ultraviolet regions.〈/p〉〈/div〉 〈/div〉 〈div xml:lang="en"〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S1386142519308704-ga1.jpg" width="301" alt="Unlabelled Image" title="Unlabelled Image"〉〈/figure〉〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 15 January 2020〈/p〉 〈p〉〈b〉Source:〈/b〉 Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 225〈/p〉 〈p〉Author(s): Chenguang Yang, Hao Deng, Yuanyuan Qian, Mingxing Li, Bing Chen, Zhenyu Xu, Ruifeng Kan〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉We report measured line intensities and air- and self-broadening coefficients for fifty-one carbon disulfide transitions in the ν1 + ν3 band near 4.6 μm. This spectral region was chosen due to the strong carbon disulfide absorption strength and in the range of the mid-infrared atmospheric window for laser-based sensing applications. Spectroscopic parameters were determined by spectra measuring with quantum cascade laser direct absorption spectroscopy and multi-line fitting with Voigt lineshape. These measured results would facilitate the development of calibrated-free mid-infrared carbon disulfide sensors.〈/p〉〈/div〉 〈/div〉 〈div xml:lang="en"〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S1386142519308686-ga1.jpg" width="484" alt="Unlabelled Image" title="Unlabelled Image"〉〈/figure〉〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 15 January 2020〈/p〉 〈p〉〈b〉Source:〈/b〉 Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 225〈/p〉 〈p〉Author(s): Tatyana Emelina, Anna Zadoroznaya, Irina Kalinovskaya, Anatolii Mirochnik〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The luminescent and photochemical properties of europium(III) cinnamates [Eu(Cin)〈sub〉3〈/sub〉]〈sub〉n〈/sub〉 (I) and Eu(Cin)〈sub〉3〈/sub〉·(phen) (II) were investigated in theoretical and experimental aspects. The high photostability of the complex I was explained. The complex II displays weak luminescence and low photostability in spite of the presence of a powerful antenna ligand 1,10-phenantroline in its coordination sphere. The unexpected luminescent and photochemical properties of europium(III) cinnamates were interpreted by the quantum chemistry methods. It was revealed that inclusion of phen molecule into Eu(Cin)〈sub〉3〈/sub〉 complex results in lengthening of Eu-Cin distances that promotes weakening of antenna effect. In the process of photoexcitation of this complex noticeable lengthening of Eu-Cin-2 bond takes place and Cin-3 ligand is detached from the molecule that is the cause of low photostability and weak luminescence of II.〈/p〉〈/div〉 〈/div〉 〈div xml:lang="en"〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S1386142519308716-ga1.jpg" width="363" alt="Unlabelled Image" title="Unlabelled Image"〉〈/figure〉〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 5 January 2020〈/p〉 〈p〉〈b〉Source:〈/b〉 Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 224〈/p〉 〈p〉Author(s): Fayan Zhu, Wenqian Zhang, Hongyan Liu, Xiufang Wang, Yongquan Zhou, Chunhui Fang, Yunhong Zhang〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉In this study, ion pairs in a single sodium tetrahydroxyborate [Na [B(OH)〈sub〉4〈/sub〉] droplet were analyzed using an “in-situ strategy” in which a sample-droplet of nanogram mass was deposited on a hydrophobic substrate and droplet was forced to enter into a supersaturated state by decreasing the relative humidity (RH) of the environment. The structure of the solvated [B(OH)〈sub〉4〈/sub〉〈sup〉−〈/sup〉] ionic moiety with various molar water-to-solute ratios (WSR) was analyzed using Raman spectroscopy. To confirm the structural changes in the droplet, electronic structure calculations were carried out using density functional theory (DFT). The frequencies calculated for the totally symmetric BO stretching vibration (〈em〉v〈/em〉〈sub〉sym(BO)〈/sub〉) of the [B(OH)〈sub〉4〈/sub〉〈sup〉−〈/sup〉] moiety were compared with those of the fundamental bands observed in the Raman spectra recorded of the droplets. The following results have been obtained: (i) when WSR is reduced from 9 to 0.1, the frequency of the band that corresponds to 〈em〉v〈/em〉〈sub〉sym(BO)〈/sub〉 shifts from 745 to 746 cm〈sup〉−1〈/sup〉, and its full-width at half-maximum value increases from 19.7 to 20.5 cm〈sup〉−1〈/sup〉; (ii) when WSR ≥7, the solvent-shared ion pair (SIP) is predominantly present in the solution, whereas in the case of WSR 〈 7, SIP transforms into a contact ion pair (CIP) formed by Na〈sup〉+〈/sup〉 and [B(OH)〈sub〉4〈/sub〉〈sup〉−〈/sup〉] in bidentate coordination; (iii) when WSR = 3, most of the CIPs transform into a cationic type of triple ion pair (TIP) composed of two Na〈sup〉+〈/sup〉 and one [B(OH)〈sub〉4〈/sub〉〈sup〉−〈/sup〉] in bidentate coordination; (iv) when WSR is further reduced, most TIP continually associate to form a more complex structure and with a small amount of six-membered ring complex also formed. These results will help us understand the ion association mechanism during dehydration process of Na[B(OH)〈sub〉4〈/sub〉] droplets.〈/p〉〈/div〉 〈/div〉 〈div xml:lang="en"〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S1386142519306985-ga1.jpg" width="426" alt="Unlabelled Image" title="Unlabelled Image"〉〈/figure〉〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 5 January 2020〈/p〉 〈p〉〈b〉Source:〈/b〉 Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 224〈/p〉 〈p〉Author(s): Zheng Fei Liu, Xue Chen, Wen Xin Wu, Gui Qi Zhang, Xin Li, Zhen Zhen Li, Wei Jun Jin〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Room temperature phosphorescence (RTP) materials have become a hot topic in fields of organic light-emitting dioes, biological sensing and imaging. The present work reports firstly that 1,3,5-trifluoro-2,4,6-triiodobenzene (TITFB) can act as a simple pure organic NIR phosphor due to its novel function in promoting n-π* transition. Also, TITFB crystal has longer phosphorescence lifetime than other ordinary multiiodoluminophors and TITFB powder. Based on the TITFB crystal structure, σ-hole and π-hole capture mechanism of n-electron is proposed, i.e., the excited state energy is decreased and n-electrons are stabilized to cause slower radiative decay rate due to the restriction of σ-hole and π-hole bond. Both computational and experimental studies support the mechanism. The new electron-capture mode is more conducive to understanding pure organic ultralong lifetime RTP.〈/p〉〈/div〉 〈/div〉 〈div xml:lang="en"〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉TITFB as a simple pure organic NIR phosphor from n-π* transition and σ- and π-hole capture state of excited electron.〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S1386142519308182-ga1.jpg" width="424" alt="Unlabelled Image" title="Unlabelled Image"〉〈/figure〉〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 5 January 2020〈/p〉 〈p〉〈b〉Source:〈/b〉 Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 224〈/p〉 〈p〉Author(s): Ashok Zachariah Samuel〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Physical properties of polymers (e.g. crystallinity, lamella thickness, thermodynamic properties etc.) can in principle be reliably estimated from their Raman spectral intensities by converting intensities to corresponding concentrations of conformers. However, such conversions are not straightforward due to the unknown scattering cross-sections. The study demonstrates that for several practical applications of Raman spectroscopy, a ratio of cross-sections can be used instead of the absolute values. A straight forwards method for accurately estimating ratio of scattering cross-section from variable temperature measurements is described here. In order to demonstrate its applicability, percent crystallinity (PC) of polyethylene has been directly estimated from Raman intensities without external calibration with other techniques. This general method can be applied to any polymer when there is a continuous change in composition of conformers over a range of temperatures.〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S1386142519308212-ga1.jpg" width="493" alt="Unlabelled Image" title="Unlabelled Image"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 5 January 2020〈/p〉 〈p〉〈b〉Source:〈/b〉 Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 224〈/p〉 〈p〉Author(s): Shargina Beegum, Y. Sheena Mary, Y. Shyma Mary, Renjith Thomas, Stevan Armaković, Sanja J. Armaković, Jan Zitko, Martin Dolezal, C. Van Alsenoy〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉This article represents the spectroscopic and computational studies of two new pyrazine compounds. In order to establish the structure and functional nature of the compounds, we have employed Fourier transformed infrared (FT-IR) and Raman spectra, nuclear magnetic resonance (NMR) spectra, and ultraviolet (UV) absorptions and have compared them with the simulated computational spectra and found that they are in the agreeable range. Simulated hyperpolarisability values are used to obtain the nonlinear optic (NLO) activity of the compound, to be used in organic electronic materials. The charge transfer and related properties was investigated by the simulation of electronic spectrum with time dependent density functional theory (TD-DFT). Natural transition orbitals (NTO) provides information about which region of the molecules are more involved in the electronic transitions and the charge transfer properties for the lowest energy excitation have been analyzed on the basis of electron density variation. Molecular dynamics simulations provide information about the behavior of the molecule in solutions. Frontier orbital analysis and study of various reactivity descriptors like ALIE and Fukui provided deep knowledge on the reactivity side. Molecular docking has been also performed to investigate the interaction between title molecules and exhibits inhibitory activity against 〈em〉Pseudomonas aeruginosa〈/em〉 Enoyl-Acyl carrier protein reductase (Fabl).〈/p〉〈/div〉 〈/div〉 〈div xml:lang="en"〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S1386142519308042-ga1.jpg" width="334" alt="Unlabelled Image" title="Unlabelled Image"〉〈/figure〉〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 5 January 2020〈/p〉 〈p〉〈b〉Source:〈/b〉 Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 224〈/p〉 〈p〉Author(s): Ruixin Xu, Wei Hu, Yanchen Zhou, Xianyi Zhang, Shu Xu, Qingyuan Guo, Ping Qi, Lingling Chen, Xuezhen Yang, Fan Zhang, Like Liu, Lijuan Qiu, Jun Wang〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Water soluble protein content (WSPC) is a parameter of great significance to the soybean food industry. So far, genetic studies and breeding practices have been limited by the lack of a rapid technique for the evaluation of WSPC. Near-infrared reflectance spectroscopy (NIRS) is widely applied for rapid quantification of many traits, including moisture, protein and oil content, and dietary fiber. The present study aimed to establish and evaluate a NIRS regression model for the rapid prediction of WSPC in soybean. Results showed that seed coat color had a profound impact on the accuracy of protein content prediction, whereas the seed coat itself deeply influenced protein determination. We established a partial least squares (PLS) regression model with 167 soybean samples whose seed coat had been removed. Based on multiplicative scatter correction and Savitsky-Golay transformation, the highest determination coefficient (R〈sup〉2〈/sup〉) was 0.831, and the relative predictive determinant was 2.417. Further analysis showed that seed roundness correlated negatively with WSPC (〈em〉r〈/em〉 = −0.59, 〈em〉P〈/em〉 〈 0.001) and greatly impacted PLS regression model prediction accuracy. The PLS model was suitable only for intact seeds whose coat had been peeled off, but not for broken seeds, soy powder, and green cotyledon soybean seeds. This study highlights the effect the seed coat has on soybean composition determination by NIRS. Moreover, the established PLS model for soybean WSPC determination could facilitate genetic studies and breeding.〈/p〉〈/div〉 〈/div〉 〈div xml:lang="en"〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S1386142519307905-ga1.jpg" width="170" alt="Unlabelled Image" title="Unlabelled Image"〉〈/figure〉〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 5 January 2020〈/p〉 〈p〉〈b〉Source:〈/b〉 Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 224〈/p〉 〈p〉Author(s): Yang-Zi Ouyang, Hai-Long Wu, Huan Fang, Tong Wang, Xiao-Dong Sun, Yue-Yue Chang, Yu-Jie Ding, Ru-Qin Yu〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The matter of fluoroquinolone residues in various foods still arouses wide public concern nowadays. In the present work, the strategy of excitation-emission matrix (EEM) fluorescence data coupled with second-order calibration method based on alternating normalization-weighted error (ANWE) algorithm was used to determine ofloxacin, lomefloxacin and ciprofloxacin in milk powder, milk and beef. Owning the unique “second-order advantage”, the ANWE-assisted analytical method was proved to successfully and eco-friendly resolve the overlapped fluorescence spectra of multi-component in complex food matrixes without tedious pretreatment steps and sophisticated high-cost instrumentations. The feasibility of the proposed method was validated by experiments. The average spiked recoveries of three fluoroquinolones range from 82.6% to 110.5% with relative standard deviations lower than 7.4%, and the limits of detection range from 0.18 and 2.41 ng mL〈sup〉−1〈/sup〉. For further evaluation, analytical figures of merit such as sensitivity and selectivity, as well as the RSDs of intra-day (≦10.6%) and inter-day (≦9.4%) were calculated. The satisfactory analytical results demonstrated that the proposed strategy could be a competitive alternative for simple, rapid and simultaneous determination of multiple fluoroquinolones in animal-derived food samples.〈/p〉〈/div〉 〈/div〉 〈div xml:lang="en"〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S1386142519308480-ga1.jpg" width="500" alt="Unlabelled Image" title="Unlabelled Image"〉〈/figure〉〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 5 January 2020〈/p〉 〈p〉〈b〉Source:〈/b〉 Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 224〈/p〉 〈p〉Author(s): Yiran Zhang, Peng Liu, Youping Li, Reggie Zhan, Zhen Huang, He Lin〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Laser-induced fluorescence (LIF) is an effective technique for non-intrusive and on-line measurement of PAHs in sooting flames but it is still need further investigation due to the complexity of PAH fluorescence characteristics. Therefore, in-depth investigations on the fluorescence spectroscopy of PAHs with different molecular structures are relevant. In this study, we investigated the fluorescence spectrum characteristics of 13 gas-phase PAHs using LIF measurement and time-dependent density functional theory (TD-DFT) calculation. The experimental results showed that the fluorescence emission wavelengths increased with more aromatic (benzenoid) rings, but this relationship no longer existed when the PAH molecules contain the five-membered ring structures. The TD-DFT calculation showed that the fluorescence emission wavelength ranges of PAHs with different molecular structures were dominantly determined by the electronic structures of highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) and their energy gaps. It was found that the saturated aliphatic branched chains (methyl and ethyl) only slightly influenced the LIF spectra, while the unsaturated aliphatic branched chains (ethenyl and ethynyl) caused remarkable redshifts. The TD-DFT results indicated that the aliphatic branched chains changed the electric structures of HOMO and LUMO of the core aromatic rings, and then influence the fluorescence emission wavelength ranges.〈/p〉〈/div〉 〈/div〉 〈div xml:lang="en"〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S1386142519308406-ga1.jpg" width="355" alt="Unlabelled Image" title="Unlabelled Image"〉〈/figure〉〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 5 January 2020〈/p〉 〈p〉〈b〉Source:〈/b〉 Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 224〈/p〉 〈p〉Author(s): Lijuan Ma, Yang Li, Leting Lei, Jingqi Zeng, Jing Zhang, Yanjiang Qiao, Zhisheng Wu〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Real-time process quality control of 〈em〉ramulus cinnamomi〈/em〉 (〈em〉cassia twig〈/em〉) is still a challenge in pharmaceutical industry. Rapid critical quality attribute (CQA) determination of 〈em〉ramulus cinnamomi〈/em〉 is essential for quality control. Microscale thermophoresis (MST) was used to investigate the CQA of 〈em〉ramulus cinnamomi〈/em〉 by the interaction with biomacromolecule. There was a good affinity between cinnamaldehyde and human serum albumin (HSA) with 〈em〉K〈/em〉〈sub〉a〈/sub〉 as 2.1722 × 10〈sup〉3〈/sup〉 mol/L. It was an excellent combination of similarity to ibuprofen with same binding force as discovered as hydrogen bond and van der Waals force. Furthermore, regarding cinnamaldehyde as CQA, on-line near-infrared was used to monitor pilot extraction process of 〈em〉ramulus cinnamomi〈/em〉 combined with high performance liquid chromatography (HPLC). Quantitative model was established with R〈sub〉pre〈/sub〉〈sup〉2〈/sup〉 as 0.9798 and RMSECV as 0.0993, suggesting the NIR model was so robust and accurate for pilot process quality control. This method provided a perfect guideline for rapid CQA determination and real-time process quality control of Chinese materia medica (CMM) based on a vital CQA.〈/p〉〈/div〉 〈/div〉 〈div xml:lang="en"〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S1386142519308534-ga1.jpg" width="355" alt="Unlabelled Image" title="Unlabelled Image"〉〈/figure〉〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 5 January 2020〈/p〉 〈p〉〈b〉Source:〈/b〉 Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 224〈/p〉 〈p〉Author(s): Shuoyang Zhang, Hui Chen, Ruiyun Li, Zhiguo Yu, Feng Lu〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉As expired medical products can be repackaged and sold by unscrupulous counterfeiters, it is essential to find a rapid and convenient method for distinguishing expired and unexpired drugs. Standard detection methods such as high-performance liquid chromatography (HPLC) and thin-layer chromatography are complex, time-consuming, and require organic solvents (that are environmentally unfriendly). Additionally, the Pharmacopoeia publications do not include information about identifying expired drugs. In this study, we proposed a novel method for identifying expired medications based on Raman spectra and verified it using 〉20 types of expired (Old) and unexpired (New) drugs, each type from the same manufacturer. A portable Raman spectrometer was used to collect Raman spectra of all samples and the similarities between the Old and New drugs (S〈sub〉N-O〈/sub〉) were evaluated. Drugs with S〈sub〉N-O〈/sub〉 values 〈0.9 were classified directly as expired drugs. For drugs with S〈sub〉N-O〈/sub〉 values 〉0.9, the content of active pharmaceutical ingredient (API) might be so low (below or around 10 wt%) that its Raman signal is largely obscured by that of the excipients. In such cases, changes in the API content are undetectable using the portable instrument. Therefore, we adopted Raman mapping technology and established a virtual imaging map to locate areas of high API content. The similarities between the Old or New spectrum and that of the API (S〈sub〉O-A〈/sub〉 and S〈sub〉N-A〈/sub〉, respectively) were calculated after removing the signal from the excipients. Our novel methods provide a precise, rapid, convenient, and environmentally friendly way to identify expired drugs that is more effective than the standard HPLC assay.〈/p〉〈/div〉 〈/div〉 〈div xml:lang="en"〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉Expired and unexpired drugs were discriminated by Raman spectrometer and mapping technology, combining generation of Virtual Imaging Map (VIM), and finding the most similar-to-API pixel (M point) before deduction of excipients.〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S1386142519307978-ga1.jpg" width="454" alt="Unlabelled Image" title="Unlabelled Image"〉〈/figure〉〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 5 January 2020〈/p〉 〈p〉〈b〉Source:〈/b〉 Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 224〈/p〉 〈p〉Author(s): Lin Li, Juan Chen, Yang Li, Nan Song, Lulu Zhu, Zhiying Li〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Detecting NAA in food has drawn intense attention as it has imposed significant threat to people's health and the growth of food industry. Over the past few years, great importance has been attached to the application of copper nanomaterials as fluorescent probe to food and environmental detection. Here, the simple, rapid, cost effective and water soluble fluorescent copper nanoparticles were synthesized with chemical reduction sonochemical assisted method for highly selective and sensitive detection of α-naphthaleneacetic acid (NAA) by using 2-mercaptobenzothiazole (MBT) as a protecting agent and polyvinylpyrrolidone (PVP) as a stabilizing agent (MBT-PVP CuNPs). The resultant CuNPs has a spherical shape with an average diameter of 10–15 nm and strong fluorescent pink emission characteristic peak at 580 nm upon 334 nm excitation. Interestingly, upon the addition of NAA, the fluorescence of MBT-PVP CuNPs can be effectively quenched for the reason that NAA could interact with MBT via hydrogen bonding and conform copper-NAA clathrate with Cu〈sup〉+〈/sup〉 via coordination bond, which shows a good linearity in the range of NAA from 0.5 to 50 μM and with a detection limit of 9.6 nM. Moreover, the prepared probe has good selectivity for NAA detection over other co-existing molecules. It is worth mentioning that this method has been successfully applied to authentic comestible sample analysis and obtained satisfying and promising results, which indicates that this strategy is likely to have a promising application potential for NAA detection in the field of food safety.〈/p〉〈/div〉 〈/div〉 〈div xml:lang="en"〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S1386142519308236-ga1.jpg" width="301" alt="Unlabelled Image" title="Unlabelled Image"〉〈/figure〉〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 5 January 2020〈/p〉 〈p〉〈b〉Source:〈/b〉 Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 224〈/p〉 〈p〉Author(s): Jenny Jeehan Nasr, Shereen Shalan〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Five Selective, rapid and sensitive spectrofluorimetric methods were performed in this study for the simultaneous estimation of amlodipine besylate (AML) and atorvastatin (ATR) in their binary mixtures and combination polypills that are used for management of cardiovascular conditions. The first method depends on micelle-enhanced first derivative synchronous fluorimetric analysis (method I) and the other four methods are multivariate analysis techniques based on the use of factor-based calibration prediction methods comprising partial least squares (PLS), Principal Component Regression (PCR), genetic algorithm PLS (GA-PLS) and genetic algorithm PCR (GA-PCR). The synchronous fluorescence spectra of the solutions were measured at a constant wavelength difference; Δλ = 100 nm. The magnitudes of the peaks of the first derivative spectra (1D) were measured at 292 nm and 387 nm for ATR, and AML correspondingly. The multivariate models were constructed utilizing fifteen mixtures as a calibration set and ten mixtures as a validation set. The linearity of all the methods was in the concentration ranges of (0.1–4.0 μg mL〈sup〉−1〈/sup〉, 0.4–10.0 μg mL〈sup〉−1〈/sup〉) for AML and ATR, correspondingly. Statistical analysis revealed no significant difference between the proposed methods and the reference method. The validity of the proposed methods allows their suitability for quality control work. All the analysis settings were optimized and all the suggested procedures were applied productively for the determination of both drugs in synthetic mixtures, validation set, and combination polypills.〈/p〉〈/div〉 〈/div〉 〈div xml:lang="en"〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S1386142519308200-ga1.jpg" width="276" alt="Unlabelled Image" title="Unlabelled Image"〉〈/figure〉〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 5 January 2020〈/p〉 〈p〉〈b〉Source:〈/b〉 Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 224〈/p〉 〈p〉Author(s): Sagar B. Yadav, Sumeet S. Sonvane, Nagaiyan Sekar〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Novel Donor (D)-π-Acceptor (A) NLOphoric triphenylamine-imidazole based dye 〈strong〉9〈/strong〉 was designed, synthesized, and confirmed by Mass, 〈sup〉13〈/sup〉C NMR, and 〈sup〉1〈/sup〉H NMR analysis. Photophysical properties of 〈strong〉9〈/strong〉 were studied in solvents of different polarities and compared with analogues compounds 〈strong〉7〈/strong〉 and 〈strong〉8〈/strong〉. Phenonthroline acceptor based dye 〈strong〉9〈/strong〉 shows highly bathochromic shifted absorption and emission compared to dyes 〈strong〉7〈/strong〉 and 〈strong〉8〈/strong〉. Positive solvatochromism was noticed in 〈strong〉7〈/strong〉, 〈strong〉8〈/strong〉, and 〈strong〉9〈/strong〉 which was supported by the linear (i.e. Lippert-Mataga and Mac-Rae polarity functions) and multi-linear (i.e. Kamlet-Taft and Catalan parameters) analysis. Moreover, solvent polarizability (d〈sub〉SP〈/sub〉) and solvent dipolarity (C〈sub〉SdP〈/sub〉) are the major factors responsible for red shift in absorption as well as in emission spectra. Charge transfer descriptors as well as the polarity graphs are in good relation with Generalized Mulliken-Hush (GMH) parameters. NLO properties of 〈strong〉7〈/strong〉, 〈strong〉8〈/strong〉, and 〈strong〉9〈/strong〉 were studied by using solvatochromic and computational methods. The static first hyperpolarizability (β〈sub〉0〈/sub〉) and relevant microscopic parameters (μ,α〈sub〉0〈/sub〉,α,β,γ) were determined using DFT with B3LYP, BHHLYP, and CAM-B3LYP functionals. Third-order NLO properties of nitrogen containing phenanthroline based compound 〈strong〉9〈/strong〉 were observed to be several times higher than those of the compounds 〈strong〉7〈/strong〉 and 〈strong〉8〈/strong〉, justify the design approach.〈/p〉〈/div〉 〈/div〉 〈div xml:lang="en"〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S138614251930811X-ga1.jpg" width="415" alt="Unlabelled Image" title="Unlabelled Image"〉〈/figure〉〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 5 January 2020〈/p〉 〈p〉〈b〉Source:〈/b〉 Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 224〈/p〉 〈p〉Author(s): Xiaoming Dou, Yubin Zhao, Mingda Li, Qinmiao Chen, Yoshinori Yamaguchi〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Raman microspectroscopy as a non-invasive and label-free technique was applied to diagnose the early stage differentiation of mouse embryonic stem cells. The differentiated and undifferentiated embryonic bodies (EBs) were cultured using handing drop method by the control of Leukemia Inhibitory Factor (LIF). Raman spectra of the periphery cells of differentiated EBs (PrE cells) and those of the interior of undifferentiated EBs (ES cells) were obtained to diagnose the stem cells of different differentiation. It was found from the spectra that the protein content increased as the cells differentiated. Principal component analysis (PCA) was carried out to further analyze the differences between ES cells and PrE cells. The first three principle components contained 98.19% from the total variance. Characteristic bands of ES and PrE cells were chosen to acquire Raman images of two cells according to the results of PCA. In the Raman images, PrE cells had a clear and bright outline in the peripheral areas while ES cells were difficult to identify, this could be a distinct characteristic to discriminate them. The result of the Raman images was consistent with the biological agreement that the differentiated cells were distributed around the periphery.〈/p〉〈/div〉 〈/div〉 〈div xml:lang="en"〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S1386142519308285-ga1.jpg" width="301" alt="Unlabelled Image" title="Unlabelled Image"〉〈/figure〉〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 5 January 2020〈/p〉 〈p〉〈b〉Source:〈/b〉 Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 224〈/p〉 〈p〉Author(s): Miao Yu, Chun-Shan Zuo, Ning Zhang〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Rational design chelating fluorescent sensors probing metal ions in biological system are continuously hot essays nowadays, especially for zinc detection. Herein, a naphthylideneimine based zinc fluorescence probe (〈strong〉3〈/strong〉) was prepared and characterized in this work. Structural features and optical properties of 〈strong〉3〈/strong〉 and its metallic complexes were characterized. Fluorescent experiment indicates 〈strong〉3〈/strong〉 is extremely sensitive and selective for Zn〈sup〉2+〈/sup〉 with a strong fluorescence enhancement (~34 folds) in aqueous buffer solution with a limit of detection (LOD) of 3.78 × 10〈sup〉−7〈/sup〉 mol L〈sup〉−1〈/sup〉. Formation constant (log〈em〉K〈/em〉〈sub〉a〈/sub〉) of the chelating complex of 〈strong〉3〈/strong〉 and Zn〈sup〉2+〈/sup〉 ion was determined to be 4.45. Theoretical studies were carried out to get deep insight into the response mechanism in the sensing process. Density functional theory (DFT) methods calculated formation Gibbs free energy (Δ〈sub〉r〈/sub〉G〈sub〉m〈/sub〉〈sup〉ө〈/sup〉) of the deprotonated complexes model (〈strong〉3〈/strong〉〈sup〉2−〈/sup〉 〈strong〉⊃〈/strong〉 〈strong〉Zn〈/strong〉) is −2.9 kcal/mol, which is in good agreement with the experimental result. The calculation results show that the low excitation states can be ascribe to S0 → T2 and S0 → S1 at 390–430 nm and 310–330 nm, respectively, due to the π → π* transition. Finally, yeast cell imaging experiments indicate that 〈strong〉3〈/strong〉 can monitor intracellular Zn〈sup〉2+〈/sup〉 as well. These findings would enable this fluorescent probe to be used as a Zinc sensor.〈/p〉〈/div〉 〈/div〉 〈div xml:lang="en"〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S1386142519307796-ga1.jpg" width="434" alt="Unlabelled Image" title="Unlabelled Image"〉〈/figure〉〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 5 January 2020〈/p〉 〈p〉〈b〉Source:〈/b〉 Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 224〈/p〉 〈p〉Author(s): Xilang Jin, Jingkai Gao, Ting Wang, Wan Feng, Rong Li, Pu Xie, Lele Si, Hongwei Zhou, Xianghan Zhang〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Herein, we presented two novel turn-on colorimetric and fluorescent probes based on a F〈sup〉−〈/sup〉 triggered Si〈img src="https://sdfestaticassets-eu-west-1.sciencedirectassets.com/shared-assets/16/entities/sbnd"〉O bond cleavage reaction, which displayed several desired properties for the quantitative detection for F〈sup〉−〈/sup〉, such as high specificity, rapid response time (within 3 min) and naked-eye visualization. The fluorescence intensity at 574 nm (absorbance at 544 nm) of the solution was found to increase linearly with the concentration of F〈sup〉−〈/sup〉 (0.00–30.0 μM) with the detection limit was estimated to be 0.47 μM/0.48 μM. Based on these excellent optical properties, the probes were employed to monitor F〈sup〉−〈/sup〉 in real water samples and tea samples with satisfactory. Furthermore, it was successfully applied for fluorescent imaging of F〈sup〉−〈/sup〉 in living nude mice, suggesting that it could be used as a powerful tool to predict and explore the biological functions of F〈sup〉−〈/sup〉 in physiological and pathological processes.〈/p〉〈/div〉 〈/div〉 〈div xml:lang="en"〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S1386142519308571-ga1.jpg" width="249" alt="Unlabelled Image" title="Unlabelled Image"〉〈/figure〉〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 5 January 2020〈/p〉 〈p〉〈b〉Source:〈/b〉 Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 224〈/p〉 〈p〉Author(s): Yanjing Dong, Zikang Chen, Meirong Hou, Li Qi, Chenggong Yan, Xiaodan Lu, Ruiyuan Liu, Yikai Xu〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Mitochondria are essential organelles in eukaryotic cells and act as the energy powerhouse and biosynthetic compartment. Fluorescent dyes are widely used powerful molecular tools for analytical sensing and optical imaging. Low photostability, short excitation and emission wavelengths, and aggregation-induced quenching effects restrict the application of traditional commercial mitochondrial fluorescent probes for bioimaging. In this study, using rhodamine as the acceptor and phenothiazine as the donor, we synthesized a novel mitochondrial-targeted near infrared (NIR) fluorescent probe, MIT-PZR. Due to low cytotoxicity, great photostability and high specificity for mitochondria targeting, MIT-PZR has enormous potential for cell imaging. Furthermore, with a sizeable Stokes shift (emission peak at 705 nm), MIT-PZR penetrated tissues providing stable red fluorescence for imaging 〈em〉in vivo〈/em〉. The histological assessment of various tissues after treatment with MIT-PZR indicated that it has good biocompatibility. Thus, MIT-PZR is a promising mitochondrial NIR fluorescent probe for future application in clinical diagnosis and modern biological research.〈/p〉〈/div〉 〈/div〉 〈div xml:lang="en"〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉An AIE-active, near-infrared fluorescent probe (MIT-PZR) based on an energy donor-acceptor (D-A)-type structure is explored for fluorescent visualization and detection of mitochondria in view of a large Stokes shift, NIR emission, excellent photostability, and mitochondria-targeted.〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S1386142519308467-ga1.jpg" width="310" alt="Unlabelled Image" title="Unlabelled Image"〉〈/figure〉〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 5 January 2020〈/p〉 〈p〉〈b〉Source:〈/b〉 Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 224〈/p〉 〈p〉Author(s): Aiqing Feng, Fangru Jiang, Guiyuan Huang, Peilian Liu〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Anionic surfactants were widespread used in car cleaning agents, household detergents, agricultural and industrial processes, and considered as a major source of environmental pollutant. Therefore, it is necessary to develop a fast, simple, highly selective and sensitive probe for the detection of anionic surfactants. Here, we synthesized two aggregation induced emission (AIE)-active molecules 4,4′,4″,4‴-(ethene-1,1,2,2-tetrayltetrakis(benzene-4,1-diyl))tetrakis (1-(4-bromobenzyl)pyridin-1-ium) bromide (〈strong〉TPE〈/strong〉-〈strong〉Br〈/strong〉) and 4,4′,4″,4‴-(ethene-1,1,2,2-trayltetrakis(benzene-4,1-diyl))tetrakis(1-methylpyridin-1-ium)iodide (〈strong〉TPE〈/strong〉-〈strong〉I〈/strong〉), which were then applied as fluorescence probes for detecting sodium dodecyl sulfate (SDS) with high selectivity and sensitivity. In the presence of SDS, a multi-fold fluorescence emission intensity enhancement was observed in both two probes (〈strong〉TPE〈/strong〉-〈strong〉Br〈/strong〉 and 〈strong〉TPE〈/strong〉-〈strong〉I〈/strong〉) due to the electrostatic self-assembly of AIE molecular. The limits of detection are 71.5 and 120 nM for 〈strong〉TPE〈/strong〉-〈strong〉Br〈/strong〉 and 〈strong〉TPE〈/strong〉-〈strong〉I〈/strong〉, respectively. This study may provide a new strategy for environmental monitoring by AIE-based fluorescent probe.〈/p〉〈/div〉 〈/div〉 〈div xml:lang="en"〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉Two cationic fluorescent probes (〈strong〉TPE-Br〈/strong〉 and 〈strong〉TPE-I〈/strong〉) were designed and synthesized for detecting sodium dodecyl sulfonate (SDS) with high selectivity and sensitivity. In the presence of SDS, a multi-fold fluorescence emission intensity enhancement was observed in the both of two probes due to the electrostatic self-assembly of AIE molecular.〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S1386142519308364-ga1.jpg" width="404" alt="Unlabelled Image" title="Unlabelled Image"〉〈/figure〉〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 5 January 2020〈/p〉 〈p〉〈b〉Source:〈/b〉 Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 224〈/p〉 〈p〉Author(s): Xueqin Jiang, Zengjin Liu, Youzhe Yang, Hao Li, Xiaoyi Qi, Wen Xiu Ren, Mingming Deng, Muhan Lü, Jianming Wu, Sicheng Liang〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉A novel two-photon pH probe, 3-benzimidazole-7-hydroxycoumarin (〈strong〉BHC〈/strong〉), was designed and synthesized based on the structures of hydroxycoumarin and benzimidazole. 〈strong〉BHC〈/strong〉 showed good linearity in the pH ranges of 3.30–5.40 (pKa = 4.20) and 6.50–8.30 (pKa = 7.20) at a maximum emission wavelength of 480 nm. 〈strong〉BHC〈/strong〉 in acidic and alkaline media could be distinguished by an obvious spectral shift of the maximum absorption wavelength from 390 nm to 420 nm. In addition, 〈strong〉BHC〈/strong〉 was well localized to mitochondria and successfully applied to one-photon and two-photon imaging of pH changes in the mitochondria of HeLa cells. The findings presented herein suggest that 〈strong〉BHC〈/strong〉 can serve as an excellent fluorescent probe for selectively sensing mitochondrial pH changes with remarkable photostability and low cytotoxicity.〈/p〉〈/div〉 〈/div〉 〈div xml:lang="en"〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S138614251930825X-ga1.jpg" width="500" alt="Unlabelled Image" title="Unlabelled Image"〉〈/figure〉〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 5 January 2020〈/p〉 〈p〉〈b〉Source:〈/b〉 Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 224〈/p〉 〈p〉Author(s): Manuel J. Schuler, Raphael Henn, Christian G. Kirchler, Inge Schlapp-Hackl, Christian W. Huck, Thomas S. Hofer〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉 〈p〉In this article the extension of the grid-based Numerov approach to probe two coupled, localised vibrational modes is assessed. The theoretically obtained wave numbers are compared to experimental results for five increasingly complex organic molecules carrying two OH groups measured in gas-phase as well as carbon tetrachloride. By using an appropriate spacing of the associated potential energy grid a deviation of the predicted wave numbers with experiment of ≤1% is achieved for both the fundamental and the first overtone bands. In particular the calculated wave numbers of aliphatic species in vacuum underline the versatility of this approach. In addition, it is demonstrated that bicubic interpolation is a viable strategy to greatly reduce the required data points and thus, the computational effort. Comparison of predicted wave numbers obtained for different conformers with experimental data enables the identification of the most relevant conformer present in solution.〈/p〉 〈p〉Since especially the accurate calculation of overtone vibrations is known to be challenging in case of strongly anharmonic potentials such as OH bonds, the presented approach provides a particularly efficient route to study the properties of the associated overtone contribution under the influence of inter-mode coupling. This is due to the fact that the Numerov approach requires no assumption about form and composition of the vibrational wave functions. In addition, the presented method also provides one of the simplest routes to access combined excitations of the considered vibrational modes.〈/p〉 〈/div〉 〈h5〉Graphical Abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S138614251930767X-ga1.jpg" width="500" alt="Unlabelled Image" title="Unlabelled Image"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 5 January 2020〈/p〉 〈p〉〈b〉Source:〈/b〉 Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 224〈/p〉 〈p〉Author(s): Mahmoud M. Sebaiy, Sobhy M. El-Adl, Amr A. Mattar〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Six simple, specific, accurate and precise spectrophotometric methods were developed for the first time analysis of some co-administered drugs with paracetamol in their mixture form without prior separation. Paracetamol & orphenadrine citrate were determined by using dual wavelength, bivariate, ratio difference, ratio derivative and mean centering of ratio spectra methods. Paracetamol & caffeine were determined by using ratio difference, ratio derivative and mean centering of ratio spectra methods. Paracetamol & diclofenac sodium were determined by using advanced absorption subtraction, ratio difference, ratio derivative and mean centering of ratio spectra methods. All of these methods were validated according to ICH guidelines where accuracy, precision, repeatability and robustness were found to be within the accepted limits. Advantages and limitations of each method are demonstrated and statistical comparison between the proposed methods was performed.〈/p〉〈/div〉 〈/div〉 〈div xml:lang="en"〉 〈h5〉Graphical abstract〈/h5〉 〈div〉 〈p〉Six spectrophotometric methods can be used to resolve the overlapping of some co-administered drugs with paracetamol such as paracetamol & orphenadrine citrate, paracetamol & caffeine and paracetamol & diclofenac sodium.〈/p〉 〈p〉Overlapping spectra of some co-administered drugs with paracetamol.〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S1386142519308194-ga1.jpg" width="500" alt="Unlabelled Image" title="Unlabelled Image"〉〈/figure〉〈/p〉 〈/div〉 〈/div〉

Description: 〈p〉Publication date: 5 January 2020〈/p〉 〈p〉〈b〉Source:〈/b〉 Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 224〈/p〉 〈p〉Author(s): Shutao Wang, Junzhu Wang, Fengkai Shang, Yutian Wang, Qi Cheng, Na Liu〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉In this paper, we have proposed a method to detect a mixture of carbamate pesticides using a back propagation network (BP), which is optimized by genetic algorithm (GA) for quantitative analysis. This method aims to combine the advantages of BP and GA to remedy their drawbacks. The training samples were taken as input, some performance indexes such as the predicted values, iteration time, mean squared error, correlation coefficient and recovery rate were compared between BP neural network and the constructed GA-BP model to evaluate the performance of two neural networks. Results show that the optimized GA-BP model can effectively predict the concentrations, the mean squared error and recovery rate are better. In addition, the correlation coefficient has a significant improvement. This study can provide a new way for detection of the pesticides mixture and help to analysis in a reliable way.〈/p〉〈/div〉 〈/div〉 〈div xml:lang="en"〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S1386142519307863-ga1.jpg" width="247" alt="Unlabelled Image" title="Unlabelled Image"〉〈/figure〉〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 5 January 2020〈/p〉 〈p〉〈b〉Source:〈/b〉 Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 224〈/p〉 〈p〉Author(s): Zhao Mu〈sup〉a〈/sup〉, Jianhao Hua〈sup〉a〈/sup〉, Yaling Yang〈sup〉a〈/sup〉〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The application of fluorescent carbon dots in bio-imaging has huge positive significance in the field of biomedicine. By taking this advantage, herein we prepared nitrogen, sulfur and iodine doped carbon dots (N,S,I-CDs) by a facile hydrothermal reaction using C〈sub〉3〈/sub〉N〈sub〉3〈/sub〉S〈sub〉3〈/sub〉, potassium iodate (KIO〈sub〉3〈/sub〉) and ethylenediamine (EDA), and the obtained N,S,I-CDs show bright blue fluorescence with a high fluorescence quantum yield of about 32.4%. The prepared N, S, I-CDs could interact with the folic acid (FA) with high selectivity, lead to development of a high sensitive method for the FA detection from 0.1 to 175 μM wide linear range with a detection limit of 84 nM (S/N = 3) and also applied them in U-2 OS cells imaging. Moreover, this sensor possessed a good sensitivity, linearity and reversibility in the temperature range of 10–80 °C, and successfully applied for the temperature sensing in cell HT-29 samples. This investigation illustrates that as-prepared N, S, I-CDs probe may have great potential as a high-performance platform for the accurate recognition of temperature in cells and could provide a new tool for the detection of FA in cells.〈/p〉〈/div〉 〈/div〉 〈div xml:lang="en"〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S1386142519308340-ga1.jpg" width="347" alt="Unlabelled Image" title="Unlabelled Image"〉〈/figure〉〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 5 January 2020〈/p〉 〈p〉〈b〉Source:〈/b〉 Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 224〈/p〉 〈p〉Author(s): Yong Du, Yaguo Wang, Jiadan Xue, Jianjun Liu, Jianyuan Qin, Zhi Hong〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉In order to characterize molecular structures of 2,4,6-trihydroxybenzoic acid (PCA) by means of vibrational spectroscopic techniques, we report investigation of PCA monohydrated form and its anhydrous polymorphic one by using terahertz and Raman spectral characterization. The experimental THz spectra show that the monohydrated PCA only has two absorption bands at 0.69 and 1.65 THz respectively in the frequency region from 0.2 to 1.8 THz, meanwhile the anhydrous form has a few significantly different absorption bands at 0.75, 1.01, 1.46 and 1.64 THz, respectively. Furthermore, Raman spectra characterized such differences of vibrational modes shown within 200–1800 cm〈sup〉−1〈/sup〉 region about the monohydrated and anhydrous forms of PCA. In view of various possible theoretical structural forms that may exist in anhydrous PCA and its monohydrated one, density functional theory calculations were performed to simulate optimized structures and vibrational mode of above two PCA polymorphic forms. Theoretical results and experimental THz/Raman spectra of anhydrous PCA show that the dimer synthon via the carboxylic group ••• carboxyl group and its ortho-phenolic hydroxyl group inter-molecular hydrogen bonding interaction establishing the theoretical form I (AH-I) is more consistent with experimental observation than other theoretical forms (AH-II and AH-III). Meanwhile, the theoretical monohydrated form I (MH-I), which is formed by the linkage of carboxyl group and its ortho-phenolic hydroxyl group with water molecule, is also much more agreement with experimental spectral observations of PCA monohydrate than other monohydrated forms (MH-II and MH-III). Our study demonstrates effectively qualitative analysis of both micro-molecular structures and dehydrated transitions between anhydrous and hydrated polymorphic forms of PCA, thus providing rich information on the corresponding structural changes of anhydrous and hydrated PCAs due to various inter-molecular and intra-molecular interactions based on their finger-print vibrational spectra combined with theoretical simulations.〈/p〉〈/div〉 〈/div〉 〈div xml:lang="en"〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S1386142519308261-ga1.jpg" width="335" alt="Unlabelled Image" title="Unlabelled Image"〉〈/figure〉〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 5 January 2020〈/p〉 〈p〉〈b〉Source:〈/b〉 Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 224〈/p〉 〈p〉Author(s): Yan Chen, Yongzhe Piao, Xia Feng, Xi Yu, Xiaoning Jin, Guangjiu Zhao〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉In this work, density functional theory (DFT) and time density functional theory (TDDFT) methods were employed to investigate the nature of the double fluorescence emission of DEAHF in these three solvents. We analyzed the geometric structures, vibrational frequencies, frontier molecular orbitals (MOs), molecular electrostatic potential surface (MEPS), calculated absorption and fluorescence spectra and the potential-energy curves for DEAHF. All the results show that the intramolecular hydrogen bond of DEAHF is strengthened from S〈sub〉0〈/sub〉 to S〈sub〉1〈/sub〉 and the electron density redistribution occurs between the proton acceptor and donor, which can facilitate ESIPT. Moreover, the geometric structures, absorption and emission spectra, MEPS and potential-energy curve of DEAHF are identical. It reveals theoretically that ACN and PC can maintain the polarity of the solvent with 1:1 mixing, which is consistent with the experimental results.〈/p〉〈/div〉 〈/div〉 〈div xml:lang="en"〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S1386142519308066-ga1.jpg" width="361" alt="Unlabelled Image" title="Unlabelled Image"〉〈/figure〉〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 5 January 2020〈/p〉 〈p〉〈b〉Source:〈/b〉 Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 224〈/p〉 〈p〉Author(s): Qisheng Deng, Zece Zhu, Xuewen Shu〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Molecular motion plays an important role in the reverse intersystem crossing of thermally activated delayed fluorescence (TADF) materials, since the conformation varies as the molecule vibrates, leading to potential changes in the energies of excited states. Although many theoretical simulations have researched the relationship between the excited states and the molecular conformations, there are still few experimental results showing the energy level difference between different long-lived excited states. Herein, a novel method for measuring spectrally resolved luminescence lifetimes is proposed to detect the energy splitting of the long-lived excited states of a classical TADF molecule, BTZ-DMAC. A set of the time-gated luminescence spectra with different delay times were captured by a spectrograph equipped on an auto-phase-locked system, and then used for lifetime analysis at each wavelength. Unlike traditional measurement techniques, the proposed novel method does not require ultrafast laser, high-speed detector and any phase matching circuitry, thus significantly reducing the cost. This method revealed a definite energy gap between the two excited states of BTZ-DMAC with different lifetimes, indicating different conformations caused by molecular vibration. This low-cost method could be also used to detect many other luminescence materials for investigating the detail mechanisms of multiple excited states.〈/p〉〈/div〉 〈/div〉 〈div xml:lang="en"〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S1386142519308248-ga1.jpg" width="344" alt="Unlabelled Image" title="Unlabelled Image"〉〈/figure〉〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 5 January 2020〈/p〉 〈p〉〈b〉Source:〈/b〉 Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 224〈/p〉 〈p〉Author(s): Israa Zeid, Rania Al Abdallah, Nayla El-Kork, Mahmoud Korek〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉By the use of the ab initio CASSCF/(MRCI+Q) calculations in the representation 〈sup〉2s+1〈/sup〉Ʌ〈sup〉(+/−)〈/sup〉, the adiabatic potential energy curves and the dipole moment curves of the low lying states of the alkaline earth hydride anions (MgH〈sup〉−〈/sup〉, CaH〈sup〉−〈/sup〉, SrH〈sup〉−〈/sup〉 and BaH〈sup〉−〈/sup〉) have been investigated in their singlet and triplet multiplicities. The spectroscopic parameters T〈sub〉e〈/sub〉, R〈sub〉e〈/sub〉, ω〈sub〉e〈/sub〉, B〈sub〉e〈/sub〉, α〈sub〉e〈/sub〉, the dipole moment μ〈sub〉e〈/sub〉, and the dissociation energy D〈sub〉e〈/sub〉 have been also calculated for the bound states of the considered molecules. In addition, a systematic investigation of the transition dipole moment curves for the lowest 〈sup〉1〈/sup〉Σ〈sup〉+〈/sup〉-〈sup〉1〈/sup〉Π transitions has been done along with the Franck-Condon factor (FCF) corresponding to the X〈sup〉1〈/sup〉Σ〈sup〉+〈/sup〉-(1)〈sup〉1〈/sup〉Π transition. Using the canonical function approach, a rovibrational study has been performed for finding the rovibrational constants E〈sub〉v〈/sub〉, B〈sub〉v〈/sub〉, D〈sub〉v〈/sub〉 and the turning points R〈sub〉min〈/sub〉 and R〈sub〉max〈/sub〉 for the ground and different excited bound state. Efficient routes may be achieved via the diagonal FCF for the formation of cold and ultracold alkaline earth hydride anions.〈/p〉〈/div〉 〈div〉 〈h6〉PACS N〈sup〉o〈/sup〉 〈/h6〉 〈p〉31.10. + z, 31.15.A, 31.15.vn, 31.50.Df.〈/p〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉For the alkaline earth hydride molecular anions XH〈sup〉−〈/sup〉 (X = Mg, Ca, Sr and Ba), the potential energy curves in the representation 〈sup〉2s+1〈/sup〉Λ〈sup〉(+/−)〈/sup〉 have been calculated along with the spectroscopic constants, the static and transition dipole moment, the Franck-Condon factor and the rovibrational calculations of the investigated electronic states.〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S1386142519308510-ga1.jpg" width="357" alt="Unlabelled Image" title="Unlabelled Image"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 5 January 2020〈/p〉 〈p〉〈b〉Source:〈/b〉 Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 224〈/p〉 〈p〉Author(s): I.K. Petrushenko, K.B. Petrushenko〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉 〈p〉Modifications in the electronic transitions of a popular 4,4-difluoro-4-bora-3a,4a-diaza-s-indacene (〈strong〉bo〈/strong〉ron 〈strong〉dipy〈/strong〉rromethene, BODIPY) dye caused by quasi-parallel stacking with corannulene (C) were studied by means of time-dependent density functional theory (TD-DFT) with the CAM-B3LYP functional. The effects of the electron-withdrawing (CN) and electron-donating (NH〈sub〉2〈/sub〉) substituents at the 〈em〉meso〈/em〉 (8) position in the BODIPY core and the corannulene rim position on the character, location, and oscillator strengths (f) of some transitions of complexes were also discussed. To understand better the nature of the transitions, their occupied and virtual orbitals involved into the first electronic transitions as well as the electron density difference plots between excited and ground states of the complexes were investigated.〈/p〉 〈p〉The S〈sub〉0〈/sub〉 → S〈sub〉1〈/sub〉 transitions of 8H-B/C and 8NH〈sub〉2〈/sub〉-B/C complexes have a small admixture of the charge transfer (CT) character in direction from BODIPY to corannulene (B → C). They located at 2.80 and 3.11 eV, respectively, and have f of ~0.15. The 8CN-B/C complex with a stronger acceptor BODIPY part has the S〈sub〉0〈/sub〉 → S〈sub〉1〈/sub〉 transition with a higher degree of CT (B → C) at 2.32 eV with f = 0.08. The 8H-B/2NH〈sub〉2〈/sub〉-C complex with a stronger donor corannulene part has the S〈sub〉0〈/sub〉 → S〈sub〉1〈/sub〉 transition with an expressed CT(B → C)-character at 2.58 eV with f = 0.003, whereas the S〈sub〉0〈/sub〉 → S〈sub〉2〈/sub〉 transition acquires in a some extent the features of the LE(B → B) character. A much interesting situation exists in the case of the 8NH〈sub〉2〈/sub〉-B/2CN-C complex. Here we can find both CT (B → C) and CT (C → B) among the first five states. Besides this, different, higher in energy CT states and states delocalized on both molecules were observed.〈/p〉 〈/div〉 〈/div〉 〈div xml:lang="en"〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S1386142519308558-ga1.jpg" width="301" alt="Unlabelled Image" title="Unlabelled Image"〉〈/figure〉〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 5 January 2020〈/p〉 〈p〉〈b〉Source:〈/b〉 Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 224〈/p〉 〈p〉Author(s): Xing-Juan Li, Yu Li, An-Yong Liu, Yuan-Hang Tan, Jian Ling, Zhong-Tao Ding, Qiu-E Cao〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉A blue emission glutathione stabilized Au nanoclusters prepared by an Au/Histidine complex with ligand-exchanges method was used for sensing of copper ions. We found that the glutathione stabilized Au NCs which has fluorescence emission hundred times higher than the Au/Histidine complex and has a highly selective fluorescence quenching response to copper ion. Other common metal ions, such as mercury, lead, iron and zinc, which could obviously quench or enhance the fluorescence of Au/Histidine complex, do not interfere the sensing of copper using glutathione stabilized Au nanocluster. The possible quenching mechanism and the dynamic quenching process for copper detection were also discussed. The results indicated that copper in the range from 0.5 to 300.0 μM could be linearly detected and the detection could be finished quickly in 5 min. A visual detection method for copper ion that may be used to fast warn copper pollution in waters by naked eyes observation was also be developed using the glutathione stabilized Au NCs probe.〈/p〉〈/div〉 〈/div〉 〈div xml:lang="en"〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S1386142519308625-ga1.jpg" width="451" alt="Unlabelled Image" title="Unlabelled Image"〉〈/figure〉〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 5 January 2020〈/p〉 〈p〉〈b〉Source:〈/b〉 Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 224〈/p〉 〈p〉Author(s): Mahantesh Budri, Ganesh Naik, Shivaraj Patil, Prajakta Kadolkar, Kalagouda Gudasi, Sanjeev Inamdar〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉In the present study, a promising optical sensor (〈strong〉TR〈/strong〉) was designed, synthesized, characterized and its chemosensing mechanism has been explored through 〈sup〉1〈/sup〉H NMR, ESI-MS, UV–Vis absorption and emission spectral studies. This compound exhibits a drastic change in its optical properties when treated with Zn〈sup〉2+〈/sup〉, whereas other metal ions do not respond. This provides a naked eye detection for Zn〈sup〉2+〈/sup〉 ion. In methanolic medium, Zn〈sup〉2+〈/sup〉 ion induces strong fluorescence in 〈strong〉TR〈/strong〉 with large Stokes shifts up to ∼132 nm. A 5-fold increase in fluorescence intensity of 〈strong〉TR〈/strong〉 in presence Zn〈sup〉2+〈/sup〉 ion is due to inhibition of ESIPT (Excited State Intramolecular Proton Transfer) and -C=N isomerization with large increase in the ICT (Intramolecular Charge Transfer) character of 〈strong〉TR〈/strong〉 in the excited state. The Job's plot and B〈img src="https://sdfestaticassets-eu-west-1.sciencedirectassets.com/shared-assets/16/entities/sbnd"〉H plots reveal the formation of 1: 1 stoichiometry with an estimated binding constant of 3.9 × 10〈sup〉7〈/sup〉 M〈sup〉−1〈/sup〉. The detection limit of 〈strong〉TR〈/strong〉 was found to be 3.85 nM. The 〈strong〉TR〈/strong〉 could be regenerated by adding EDTA solution to the complex formed during interaction. The pH studies indicate that 〈strong〉TR〈/strong〉 could render pH dependent fluorescence measurements in a live physiological environment. Computational technique was used to optimize the structures and the theoretical results are correlated with the experimental results. The possible utilization of 〈strong〉TR〈/strong〉 as bio-imaging fluorescent sensor with 98.57% cell viability to detect Zn〈sup〉2+〈/sup〉 in HeLa cells was also explored by fluorescent cell imager.〈/p〉〈/div〉 〈/div〉 〈div xml:lang="en"〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S1386142519308522-ga1.jpg" width="349" alt="Unlabelled Image" title="Unlabelled Image"〉〈/figure〉〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 5 January 2020〈/p〉 〈p〉〈b〉Source:〈/b〉 Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 224〈/p〉 〈p〉Author(s): A. Mortadi, A. Elmelouky, M. Chahbi, N. EL Ghyati, S. Zaim, O. Cherkaoui, R. El Moznine〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The aim of the present work is to monitor the flocculation process using the analysis of the electric and dielectric properties. Therefore the dielectric and electrical characteristics of wastewater with different cationic polymer concentrations were investigated 〈em〉via〈/em〉 the impedance spectroscopy (IS) method. Impedance measurements were carried at different concentration of cationic polymer in the frequency range from 0.1 Hz to 100 kHz. The analysis of complex permittivity spectra was described by the superposition of a power law at a low frequency related to the diffusion process and Cole-Cole relaxation behavior at high frequency. Moreover, an equivalent circuit model was developed in order to analyze the experimental data and to further investigate both processes. The variation of the parameters extracted from the equivalent circuit with the increase of cationic polymer concentrations has shown a net transition at 10 mg/l. This behavior could reflect the flocculation of dispersed particles at 10 mg/l. The findings in this work could draw new attention toward the monitoring of the coagulation-flocculation process using impedance spectroscopy and could be extended to other kinds.〈/p〉〈/div〉 〈/div〉 〈div xml:lang="en"〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S1386142519308273-ga1.jpg" width="490" alt="Unlabelled Image" title="Unlabelled Image"〉〈/figure〉〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 5 January 2020〈/p〉 〈p〉〈b〉Source:〈/b〉 Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 224〈/p〉 〈p〉Author(s): Alexander Götz, Ramin Nikzad-Langerodi, Yannik Staedler, Anke Bellaire, Johannes Saukel〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Over the past decades, ATR-FTIR has emerged as promising tool for the identification of plants at the genus and (sub-) species level through surface measurements of intact leaves. Theoretical considerations regarding the penetration depth of the evanescent wave into the sample and the thickness of plant leaf cuticles suggest that the structure and composition of the cuticle represent universal taxonomic markers. However, experimental evidence for this hypothesis is scarce. In the current contribution, we present results of a series of simple experiments on epidermal monolayers derived from the bulbs of 〈em〉Allium cepa〈/em〉 L. (Amaryllidaceae) as a model system to study the effect of an IR active probe located beyond the theoretical penetration depth of the evanescent wave. We found that this probe had a significant influence on the ATR-FTIR spectra for up to 4 epidermal layers stacked on top of each other corresponding to a total thickness of around 60 μm, exceeding the theoretical penetration depth of the evanescent wave by a factor of around 20. Altogether, our data indicate a major discrepancy between theory and practice in ATR-FTIR spectroscopy in general and provide strong evidence that in general plant leaf spectra cannot be fully explained by the structure and composition of the cuticle alone.〈/p〉〈/div〉 〈h5〉Graphical Abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S1386142519308509-ga1.jpg" width="301" alt="Unlabelled Image" title="Unlabelled Image"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 5 January 2020〈/p〉 〈p〉〈b〉Source:〈/b〉 Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 224〈/p〉 〈p〉Author(s): S. Selvaraj, P. Rajkumar, M. Kesavan, K. Thirunavukkarasu, S. Gunasekaran, N. Saradha Devi, S. Kumaresan〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Chiral sulfoxide based smart drug modafinil were studied experimentally and theoretically. Vibrational spectra were recorded in the mid IR region and electronic spectra were recorded in UV–Visible region. The molecular geometry, vibrational spectra, magnetic spectra and electronic spectra were simulated using Density Functional Theory (DFT) employed with B3LYP/6–311++G(d,p) basis set. The molecular geometry optimization, vibrational frequencies, chemical shifts and solvent effect on electronic properties were reported. The intermolecular interactions have been studied by Hirshfeld surface analysis. There is good agreement was found between calculated and observed values, thereby to confirm the molecular structure of modafinil.〈/p〉〈/div〉 〈/div〉 〈div xml:lang="en"〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S138614251930839X-ga1.jpg" width="425" alt="Unlabelled Image" title="Unlabelled Image"〉〈/figure〉〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 5 January 2020〈/p〉 〈p〉〈b〉Source:〈/b〉 Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 224〈/p〉 〈p〉Author(s): Hongjin Qu, Changchun Hao, Zhezhu Nan, Xianggang Zhang, Runguang Sun〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Liposome mediated DNA transport possesses a number of preventing diseases in clinical trials, thus, the study of interaction between DNA and liposomes has become a hot research direction. In this paper, the adsorption behavior of DNA onto two representative lipids had been studied by the fluorescence spectrum measurement, Ultraviolet absorption spectrum and Langmuir-Blodgett technology. The results of fluorescence spectrum measurement indicated that the fluorescence liposomes were quenched statically by DNA at all three temperatures. Thermodynamic analysis displayed that the intermolecular forces between DNA and liposomes were van der Waals forces and Hydrogen bonding. The experimental results of Ultraviolet absorption spectrum and Langmuir-Blodgett technology further verified these mechanisms. This work provides useful theoretical basis for the development of novel DNA delivery materials.〈/p〉〈/div〉 〈/div〉 〈div xml:lang="en"〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉The binding of DNA to mixed lipids was mainly the adsorption behavior on DMPC/DPPC liposomes. The more electronegative atoms of DNA, such as oxygen, nitrogen and the like, formed hydrogen bonds with a large number of hydrogen atoms in the lipid tail chain. Besides, the DNA itself, as a polar molecule, bound to the polar head of lipids through van der Waals forces. These two forces enabled DNA to adsorb to lipid molecules and generate a static quenching of fluorescent labeled liposomes.〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S1386142519308492-ga1.jpg" width="431" alt="Unlabelled Image" title="Unlabelled Image"〉〈/figure〉〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 5 January 2020〈/p〉 〈p〉〈b〉Source:〈/b〉 Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 224〈/p〉 〈p〉Author(s): Cai Liu, Jingjing Guo, Fengling Cui〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Nucleoside drugs are known for their remarkable anticancer and antiviral properties. The development of nucleoside drugs has attracted much attention and generated a great deal of research interest. β-L-cytidine and β-D-cytidine are a pair of cytosine nucleoside enantiomers. In this work, the interactions between cytosine nucleoside enantiomers and human serum albumin were studied by ultraviolet-visible spectra, fluorescence spectrum and circular dichroism spectrum under simulated human physiological environment. The data of fluorescence spectra were corrected for the inner-filter effect to improve accuracy. Stern-Volmer quenching constants and binding constants in addition to thermodynamic parameters have been analyzed, which established that complexes formation have taken place via static quenching mechanism, and that hydrophobic force involved in these interactions. CD spectrum revealed that on addition of cytosine nucleoside enantiomers, the α-helix% of HSA increased slightly. What's more, molecular modeling method indicated that cytosine nucleoside enantiomers prefer binding at the IIIA site of HSA.〈/p〉〈/div〉 〈/div〉 〈div xml:lang="en"〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S138614251930842X-ga1.jpg" width="301" alt="Unlabelled Image" title="Unlabelled Image"〉〈/figure〉〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 5 January 2020〈/p〉 〈p〉〈b〉Source:〈/b〉 Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 224〈/p〉 〈p〉Author(s): Zhengyi Zhang, Jiajie Yu, Liyun Ma, Yangshan Sun, Pingping Wang, Tianhe Wang, Shou Peng〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉In this work, a novel Ag/AgBr/ZnO SERS substrate was prepared by calcinating spin-coated zinc acetate on glass slides in the presence of ethanolamine (EA), followed by the process of impregnating-precipitation-photoreduction treatment. The SERS performances of Ag/AgBr/ZnO substrates were evaluated using aqueous crystal violet (CV) and Rhodamine 6G (R6G) as target analytes. The effects of initial immersion precursor concentration and irradiation time on the SERS performance were systematically studied. The as-prepared SERS substrate exhibited good chemical detection sensitivity, reproducibility and reusability. The optimal Ag/AgBr/ZnO (10 mM-30 min) substrates were capable of detecting 10〈sup〉−12〈/sup〉 M CV and 10〈sup〉−11〈/sup〉 M R6G aqueous solutions. The quantitative detection by the SERS substrate was investigated by constructing a linear corresponding calibration plot. The Ag/AgBr/ZnO SERS substrate was regenerated by a simple visible light driven photocatalytic process. A plausible Z-scheme visible light photocatalytic mechanism seems to account for the Ag-ZnO-AgBr system. This SERS substrate can be separated from the reaction easily, and the results indicated that the film was reusable for eight times without significantly losing the SERS efficiency, each time accompanied by a simple photo-driven regeneration. This study reveals that the Ag/AgBr/ZnO film on glass is practically applicable as an ultra-highly sensitive SERS substrate that can be readily regenerated.〈/p〉〈/div〉 〈/div〉 〈div xml:lang="en"〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S1386142519307711-ga1.jpg" width="470" alt="Unlabelled Image" title="Unlabelled Image"〉〈/figure〉〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 5 January 2020〈/p〉 〈p〉〈b〉Source:〈/b〉 Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 224〈/p〉 〈p〉Author(s): Zhengquan Yan, Cong Wang, Yulian Tang, Yanjie Zhu, Qianying Cao, Tianran Yang, Lei Hu〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉To illustrate the impact of molecular structure, especially heterocycle unit, on the sensing performance, two kinds of π-conjugated molecules containing aromatic heterocyclic (Dye 1) and aromatic ring (Dye 2) were identified and compared each other. Even with similar structures, they possessed quite different spectral and colorimetric responses to F〈sup〉−〈/sup〉, Cl〈sup〉−〈/sup〉, Br〈sup〉−〈/sup〉, I〈sup〉−〈/sup〉, NO〈sub〉3〈/sub〉〈sup〉−〈/sup〉, HSO〈sub〉4〈/sub〉〈sup〉−〈/sup〉, H〈sub〉2〈/sub〉PO〈sub〉4〈/sub〉〈sup〉−〈/sup〉, ClO〈sub〉4〈/sub〉〈sup〉−〈/sup〉 and CH〈sub〉3〈/sub〉COO〈sup〉−〈/sup〉, etc. The reason might result from the difference in withdraw-electron ability of aromatic and heterocyclic rings, which would lead to different acidity of active H in the target π-conjugated molecules. In acidic aqueous, Dye 1 expressed a reversible ratiometric-colorimetric response to F〈sup〉−〈/sup〉, accompanying with a visual color change from bright yellow to purple, a nice linear range of 2.0–35.0 × 10〈sup〉−6〈/sup〉 mol/L and a low detection limit of 1.60 × 10〈sup〉−7〈/sup〉 mol/L. While Dye 2 did not react with any anion due to its weak acidity of active hydrogen. Under the optimized conditions, Dye 1 was successfully applied for colorimetric or naked-eye detection of F〈sup〉−〈/sup〉 in environmental water, tea and toothpaste samples with RSD ≤ 3.1%. The recognition mechanism for Dye 1 to F〈sup〉−〈/sup〉 was confirmed to be deprotonation one with a 1:1 binding stoichiometry.〈/p〉〈/div〉 〈/div〉 〈div xml:lang="en"〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉Two kinds of π-conjugated molecules containing aromatic heterocyclic (Dye 1) and aromatic ring (Dye 2) were identified and compared. With introduce of aromatic heterocycle, Dye 1 possessed more excellent sensing property to F〈sup〉−〈/sup〉, such as improved selectivity, sensitivity and reversibility, especially applicability in aqueous owing to the increasing acidity of active hydrogen atoms by deprotonation recognition mechanism.〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S1386142519308418-ga1.jpg" width="223" alt="Unlabelled Image" title="Unlabelled Image"〉〈/figure〉〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 5 January 2020〈/p〉 〈p〉〈b〉Source:〈/b〉 Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 224〈/p〉 〈p〉Author(s): Ramesh C. Sharma, Subodh Kumar, Sudhir Kumar, Mohit Mann, Mayank, Mukul Sharma〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Quantum cascade laser (QCL) based photoacoustic spectroscopic technique has been developed for detection of hazardous molecules contaminants/adsorbed on surfaces such as plastic and cloth from short standoff distances. The laser source and detection system is integrated together in a single unit. Spectra were recorded for traces of various molecules in mid-infrared spectral band (1130–1430 cm〈sup〉−1〈/sup〉) from distance of 0.5 m. Pulsed quantum cascade laser source, modulated at 25 kHz and 42 kHz frequency was used to detect molecular species adsorbed on surfaces of cloth and plastic. Ultrasonic microphones operating at 25 and 42 kHz resonant frequencies were used as detectors. The photoacoustic spectra of hazardous chemicals, explosive materials and bio-chemicals such as acetic acid, PETN (pentaerythritol tetranitrate), DPA (dipicolinic acid) in very low quantities were recorded. Sensitivities of 5 and 10 μg/cm〈sup〉2〈/sup〉 of these analytes were achieved with frequencies of 25 and 42 kHz respectively at distance of 0.5 m. In the present technique there was no interference of audio frequency (20 Hz to 20 kHz) and bright sunlight. The technique can be applied for screening of suspicious objects for homeland security and forensic applications. The present spectroscopic technique can be developed in man portable standalone product.〈/p〉〈/div〉 〈/div〉 〈div xml:lang="en"〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S1386142519308352-ga1.jpg" width="341" alt="Unlabelled Image" title="Unlabelled Image"〉〈/figure〉〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: Available online 29 March 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy〈/p〉 〈p〉Author(s): Ju-Peng Chen, Yi-Meng Duan, Wen-Jun Zheng, Qi Zhang, Qianshou Zong, Shaojin Chen, Kun-Peng Wang, Zhi-Qiang Hu〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Hydrogen sulfide (H〈sub〉2〈/sub〉S) is a kind of gaseous signal molecule in many physiological processes. In order to detect H〈sub〉2〈/sub〉S, a novel “turn on” fluorescent probe 6,12-dihydroxyperylene-1,7-dione (DPD) was designed and synthesized. The probe DPD is fluorescence silence, while the addition of H〈sub〉2〈/sub〉S induces an obvious green fluorescence with an obvious color change from dark blue to yellow-green. The probe shows excellent selectivity, fast response (2.5 min) and linear curve (0–90 μM) in wide effective pH range (4–10). Competition experiments are also revealed in corresponding studies and the detection limit is 3.6 μM. The response mechanism is proved to be the reduction of the probe by H〈sub〉2〈/sub〉S, which is confirmed by 〈sup〉1〈/sup〉H NMR. Furthermore, through the fluorescence turn-on signal toward H〈sub〉2〈/sub〉S in Hela cells, probe DPD was successfully applied to monitor H〈sub〉2〈/sub〉S in living Hela cells.〈/p〉〈/div〉 〈/div〉 〈div xml:lang="en"〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S1386142519303610-ga1.jpg" width="500" alt="Unlabelled Image" title="Unlabelled Image"〉〈/figure〉〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: Available online 29 March 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy〈/p〉 〈p〉Author(s): Regina Sisika A. Sonthanasamy, Nik Muslihuddin Nik Sulaiman, Ling Ling Tan, Azwan Mat Lazim〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Carbon dots (C-dots) were used to study the binding mechanisms with serum protein, bovine serum albumin (BSA) by using two notable binding systems known as non-covalent and covalent interaction. Interaction between C-dots and BSA were estimated by 〈em〉Stern-Volmer〈/em〉 equation and Double Log Regression Model (DLRM). According to the fluorescent intensity, quenching of model carrier protein by C-dots was due to dynamic quenching for non-covalent and static quenching for covalent binding. The binding site constant, K〈sub〉A〈/sub〉 and number of binding site, for covalent interaction is 1754.7 L/mol and n ≈ 1 (0.6922) were determined by DLRM on fluorescence quenching results. The blue shift of the fluorescence spectrum, from 450 nm to 421 nm (non-covalent) and 430 nm (covalent) and suggested that both the microenvironment of C-dots and protein changed in relation to the protein concentration. The fluorescence intensity results show that protein structure has a significant role in Protein-C-dots interactions and type of binding influence physicochemical properties of C-dots differently. Understanding to this bio interface is important to utilize both quantum dots and biomolecules for biomedical field. It can be a useful guideline to design further applications in biomedical and bioimaging.〈/p〉〈/div〉 〈/div〉 〈div xml:lang="en"〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S1386142519303567-ga1.jpg" width="374" alt="Unlabelled Image" title="Unlabelled Image"〉〈/figure〉〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: Available online 29 March 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy〈/p〉 〈p〉Author(s): Huimin Zhao, Lixin Zang, Kehua Xu, Meng Kou, Zhiguo Zhang〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉High oxygen sensitivity (the slope of the Stern-Volmer plot reaches 0.73/μM) is achieved with a phosphorescence indicator, gadolinium-hematoporphyrin monomethyl ether (Gd-HMME), by decreasing the extent of its protection. In air-saturated solution, the phosphorescence quantum efficiency (QE) of Gd-HMME in a non-rigid microenvironment is lower than that in a rigid microenvironment. In contrast, when oxygen is removed, the QE of Gd-HMME in the non-rigid microenvironment was found to be same as that of Gd-HMME in the rigid microenvironment. This indicates that Gd-HMME is much more sensitive to oxygen in the non-rigid microenvironment. The oxygen sensitivity of Gd-HMME was found to increase as the rigidity of its microenvironment decreases. The oxygen response of Gd-HMME without any protection reaches 240 (0–374 μM oxygen), whereas that in the rigid microenvironment is only 3 in this range. The measurement precision of Gd-HMME without any protection is lower than that in the rigid microenvironment. These results indicate that the measurement of oxygen in different concentration ranges would require the rigidity of the microenvironment to be varied. Gd-HMME without any protection can be applied to detect oxygen as low as 0.1 μM. The detection limit of oxygen was evaluated to be as low as 20 nM based on Gd-HMME without any protection.〈/p〉〈/div〉 〈/div〉 〈div xml:lang="en"〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉Very low oxygen detection limit (20 ppb) achieved by removing the protection of the triplet state of a phosphorescence-based oxygen indicator.〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S1386142519303555-ga1.jpg" width="500" alt="Unlabelled Image" title="Unlabelled Image"〉〈/figure〉〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: Available online 29 March 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy〈/p〉 〈p〉Author(s): Igor Medeiros de Assis, Maria Oneide Silva de Moraes, Relem Cativo da Conceição, Yonny Romaguera-Barcelay, Rodrigo Fernando Brambilla de Souza, Dunieskys Roberto González Larrudé, Maria Luiza Miranda Rocco, Walter Ricardo Brito〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Molecularly imprinted polymers provide an excellent platform for the modification of selective electrodes for sensing applications. Herein, we present a novel modified carbon paste electrode (CPE) with a selective molecularly imprinted polymer (MIP) for recognition of sesquiterpene β-caryophyllene, constituted of important plants oil-resins and extracts. The non-covalent MIP was synthesized using AA, EGDMA, and AIBN as a functional monomer, cross-linker and initiator agent, respectively. Structural and chemical characterization of the synthesized MIP was conducted through scanning electron microscopy (SEM), Fourier-transform infrared (FT-IR) spectroscopy, Raman spectroscopy and X-ray photoelectron spectroscopy (XPS). It was possible to verify the functional features of the synthesized MIP related to the extraction process of the template molecule. The CPE modified with MIP for sesquiterpene β-caryophyllene recognition was characterized by electrochemical techniques as cyclic voltammetry (CV) and square wave voltammetry (SWV). The highest selective recognition electrode enables to detect concentrations in the range between 1.5 × 10〈sup〉−7〈/sup〉 and 7.5 × 10〈sup〉−7〈/sup〉 M, showing great potential for applications in monitoring content of sesquiterpene β-caryophyllene in technological processes and for predicting the quality of extracts, oils, and resins of plants.〈/p〉〈/div〉 〈/div〉 〈div xml:lang="en"〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S1386142519303464-ga1.jpg" width="348" alt="Unlabelled Image" title="Unlabelled Image"〉〈/figure〉〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: Available online 29 March 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy〈/p〉 〈p〉Author(s): Jiemei Chen, Mingliang Li, Tao Pan, Liwen Pang, Lijun Yao, Jing Zhang〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The rapid and non-destructive discriminant analysis of rice seeds has great significance for large-scale agriculture. Using near-infrared (NIR) diffuse-reflectance spectroscopy with partial least squares-discriminant analysis (PLS-DA), a variety identification method of multi-grain rice seeds was developed. The equidistant combination method was adopted for large-range wavelength screening. A step-by-step phase-out method was proposed to eliminate interference wavelengths and improve the predicted effect. The optimal wavelength model was a combination of 54 wavelengths within 808–974 nm of the short-NIR region. One type of pure rice variety (Y Liangyou 900) was used for identification (negative). Positive samples included the other four pure varieties and contamination of Y Liangyou 900 by the above four varieties. The recognition-accuracy rates for positive, negative and total validation samples reached 93.1%, 95.1%, and 94.3%, respectively. In the long-NIR region, the local optimal wavelength model was a combination of 49 wavelengths within 1188–1650 nm, and the recognition-accuracy rates for positive, negative and total validation samples were 90.3%, 94.1%, and 92.5%, respectively. Results confirmed the feasibility of NIR spectroscopy for variety identification of multi-grain rice seeds. The proposed two discrete-wavelength models located in the short- and long-NIR regions can provide valuable reference to a dedicated spectrometer.〈/p〉〈/div〉 〈/div〉 〈div xml:lang="en"〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S1386142519303531-ga1.jpg" width="301" alt="Unlabelled Image" title="Unlabelled Image"〉〈/figure〉〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: Available online 29 March 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy〈/p〉 〈p〉Author(s): Lian Li, Shuang Quan, Danyang Li, Jiayue Wang, Hengchang Zang, Lining Zhang〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Though near infrared spectroscopy (NIRS) has been applied widely in the field of pharmaceutical, there is still a bottleneck which limits its development. The main barrier is that conventional NIRS calibration method is based on experiences and trials, which causes the established model is not stable and difficult to explain. Therefore, a new strategy which was based on design of experiment (DoE) combined with statistical analysis was provided to solve the limitations. A pre-processing method library was set up first and orthogonal experiment design was then introduced to investigate the effects and interactions of different pre-processing methods. Paired 〈em〉t-〈/em〉test was used to select the most suitable pre-processing method. Finally, the pre-processing method selected above and three commonly used variable selection methods (CARS, UVE, VIP) were combined randomly to select the best calibration model. The results showed that the new calibration approach could provide a reasonable way for researchers to establish a more stable, objective calibration model.〈/p〉〈/div〉 〈/div〉 〈div xml:lang="en"〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S1386142519303476-ga1.jpg" width="301" alt="Unlabelled Image" title="Unlabelled Image"〉〈/figure〉〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: Available online 29 March 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy〈/p〉 〈p〉Author(s): Shiva Ferdowsi, Amin Salem, Shiva Salem〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The challenge with γ-Al〈sub〉2〈/sub〉O〈sub〉3〈/sub〉 is its pH-dependent removal efficiency and relatively low adsorption capacity in recovery of wastewaters contaminated by cationic dyes. Therefore; the objective of present investigation was to fabricate a pH-independent nano-sized alumina powder by dealumination of kaolin for uptake of dye. The dealumination of meta-kaolin was carried out by nitric acid solution and the amorphous aluminum hydroxide was precipitated with ammonia in the presence of combined surfactants containing cetyltrimethylammonium bromide (CTAB), polyethylene glycol (PEG) and polyoxyethylene octyl phenyl ether (TX100). The nano-sized gamma alumina particles were fabricated after calcination at 800 °C and then were analyzed based on spectrophotometrical method. The rod-like nano-particles with average width of 5 nm and length of 20 nm were synthesized by precipitation in the presence of admixed surfactant, CTAB-TX100, which improves the removal efficiency due to efficient modification in the interaction of particles. TX100 also showed a significant affinity for increasing the specific surface area because of ability to prevent the particle aggregation which provides a potential for synthesis of alumina adsorbent without foaming, normally observed in the presence of CTAB. Both of mentioned powders indicated relatively pH-independent removal efficiency with higher adsorption capacity. Moreover, adsorption isotherm parameters were determined to verify the improvement of removal efficiency. The presented fabrication technique eventually overcame the pH-dependent recovery problem which is feasible for the development of adsorbents because the starting material is abundant, very low energy is needed, no hazardous waste is generated and applicable in the acidic environments.〈/p〉〈/div〉 〈/div〉 〈div xml:lang="en"〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S1386142519303518-ga1.jpg" width="354" alt="Unlabelled Image" title="Unlabelled Image"〉〈/figure〉〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: Available online 29 March 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy〈/p〉 〈p〉Author(s): Haiyang Gu, Yanhui Sun〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉This study attempted to develop a probe-based fluorescence technology as a rapid method to discriminate the oxidation degree of oil. The fluorescence probe was made by dissolving the selected probe in a chloroform solvent. A fluorescence landscape profile for each oil sample was obtained to discriminate fluorescence changes during the oxidation process. Parallel factor analysis (PARAFAC) was performed to extract characteristic fluorescence peaks. Then, these characteristic fluorescence peaks and chemical indicators were used to build regression models based on support vector regression (SVR). The correlation coefficients (R) and mean squared error (MSE) in the prediction sets were applied as the assessment parameters for the SVR models as follows: 〈em〉R〈/em〉 = 0.9724, MSE = 0.0088 for an acid value. This research suggests that probe-based fluorescence spectroscopy is useful for oxidation evaluation of oil and perhaps other food containing high amounts of oil.〈/p〉〈/div〉 〈/div〉 〈div xml:lang="en"〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S1386142519303488-ga1.jpg" width="500" alt="Unlabelled Image" title="Unlabelled Image"〉〈/figure〉〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: Available online 29 March 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy〈/p〉 〈p〉Author(s): Long Fan, Jing-can Qin, Chao-rui Li, Zheng-yin Yang〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Upon excitation of the visible light, probes show colorimetric and fluorescent responses to the specific metal ion, which can be easily detected by the naked eye. Owing to the excitation of the visible light at 423 nm, a novel and simple Schiff-base receptor based chromone derivative called 7-methoxychromone-3-carbaldehyde-(indole-3-formyl) hydrazone (〈strong〉MCIH2〈/strong〉) had been investigated as a selective and sensitive probe for Al〈sup〉3+〈/sup〉 with colorimetric and fluorescent responses. Upon addition of Al〈sup〉3+〈/sup〉 to compound 〈strong〉MCIH2〈/strong〉 solution, compound 〈strong〉MCIH2〈/strong〉 could respond to Al〈sup〉3+〈/sup〉 with a good selective colorimetric signal, which was easily observed from colorless to yellow-green by the naked eye. Furthermore, a remarkable fluorescence emission enhancement with an “OFF-ON” signal by over 700-fold was triggered, but other various metal ions had no such significant effects on the fluorescence emission. In addition, the detection limit of compound 〈strong〉MCIH2〈/strong〉 for recognizing Al〈sup〉3+〈/sup〉 was evaluated to be as low as 1 × 10〈sup〉−7〈/sup〉 M level, which was sufficiently low for sensing Al〈sup〉3+〈/sup〉 widely distributed in various environmental and biological systems.〈/p〉〈/div〉 〈/div〉 〈div xml:lang="en"〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S1386142519303506-ga1.jpg" width="155" alt="Unlabelled Image" title="Unlabelled Image"〉〈/figure〉〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: Available online 29 March 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy〈/p〉 〈p〉Author(s): Wenlong Li, Xu Yan, Jianchao Pan, Shaoyong Liu, Dongsheng Xue, Haibin Qu〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Near-infrared spectroscopy (NIRS) combined with chemometrics was used to analyze the main active ingredients including chlorogenic acid, caffeic acid, luteoloside, baicalin, ursodesoxycholic acid, and chenodeoxycholic acid in the 〈em〉Tanreqing〈/em〉 injection. In this paper, first, two hundred samples collected in the product line were divided into the calibration set and prediction set, and the reference values were determined by the High Performance Liquid Chromatography- Diode Array Detector/Evaporative Light Scattering Detector (HPLC-DAD/ELSD) method. Partial least squares (PLS) analysis was implemented as a linear method for models calibrated with different preprocessing means. Wavelet transformation (WT) was introduced as a variable selection technique by means of multiscale decomposition, and wavelet coefficients were employed as the input for modeling. Furthermore, two nonlinear approaches, least squares support vector machine (LS-SVM) and Gaussian process (GP), were applied to exploit the complicated relationship between the spectra and active ingredients. The optimal models for each ingredient were obtained by LS-SVM and GP methods. The performance of the final models was evaluated by the root mean square error of calibration (RMSEC), root mean square error of cross-validation (RMSECV), root mean square error of prediction (RMSEP) and correlation coefficient (R). All of the models in the paper give a good calibration ability with an R value above 0.92, and the prediction ability is also satisfactory, with an R value higher than 0.85. The overall results demonstrate that nonlinear models are more stable and predictable than linear ones, and they will be more suitable for the CHM system when high accuracy analysis is required. It can be concluded that NIRS with the LS-SVM and GP modeling methods is promising for the implementation of process analytical technology (PAT) in the pharmaceutical industry of Chinese herbal injections (CHIs).〈/p〉〈/div〉 〈/div〉 〈div xml:lang="en"〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉In this paper, we report a NIRS-based method for the determination of the main active ingredients including chlorogenic acid, caffeic acid, luteoloside, baicalin, ursodesoxycholic acid, and chenodeoxycholic acid in the 〈em〉Tanreqing〈/em〉 injection, combined with two nonlinear chemometrics approaches, least squares support vector machine (LS-SVM) and Gaussian process (GP). The overall results demonstrate that the proposed method can be used as an advantageous alternative in the quality inspection of 〈em〉Tanreqing〈/em〉 injection.〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S1386142519303580-ga1.jpg" width="339" alt="Unlabelled Image" title="Unlabelled Image"〉〈/figure〉〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: Available online 29 March 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy〈/p〉 〈p〉Author(s): Venkatadri Tekuri, Suban K. Sahoo, Darshak R. Trivedi〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Simple pyrene-based chemosensors 1 to 3, were synthesized from pyrene-1-carboxaldehyde and they were characterized using various spectroscopic techniques like UV–Vis, FT-IR, Mass, 〈sup〉1〈/sup〉H NMR and 〈sup〉13〈/sup〉C NMR. Among synthesized receptors, the receptor 1 shows high selectivity towards Hg〈sup〉2+〈/sup〉 ions. Further, the high selectivity of receptor 1 towards Hg〈sup〉2+〈/sup〉 ions in the presence of various other interfering metal ions like Ni〈sup〉2+〈/sup〉, Zn〈sup〉2+〈/sup〉, Mn〈sup〉2+〈/sup〉, Co〈sup〉2+〈/sup〉, Cu〈sup〉2+〈/sup〉, Cr〈sup〉3+〈/sup〉, Fe〈sup〉3+〈/sup〉, Al〈sup〉3+〈/sup〉, Ag〈sup〉+〈/sup〉, Fe〈sup〉2+〈/sup〉, Cd〈sup〉2+〈/sup〉, Mg〈sup〉2+〈/sup〉, Pb〈sup〉2+〈/sup〉, Ca〈sup〉2+〈/sup〉, Na〈sup〉+〈/sup〉, K〈sup〉+〈/sup〉 was confirmed by UV–Vis and fluorescence methods. The detection limit for Hg〈sup〉2+〈/sup〉 ions was found to be 0.270 μM. The chemodosimetric irreversible hydrolysis of the receptor 1 in the presence of Hg〈sup〉2+〈/sup〉 was studied by UV/Vis, fluorescence, FT-IR, LC-MS, 〈sup〉1〈/sup〉H NMR and theoretical DFT study. Further, the real life applications of receptor 1 for the determination of Hg〈sup〉2+〈/sup〉 ions were demonstrated by UV–Vis method.〈/p〉〈/div〉 〈/div〉 〈div xml:lang="en"〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S1386142519303543-ga1.jpg" width="475" alt="Unlabelled Image" title="Unlabelled Image"〉〈/figure〉〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: Available online 29 March 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy〈/p〉 〈p〉Author(s): Yanfeng Tang, Yang Huang, Yihan Chen, Linxia Lu, Chun Wang, Tongming Sun, Miao Wang, Guohua Zhu, Yun Yang, Lin Zhang, Jinli Zhu〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉A novel coumarin-derived Schiff base fluorescence probe (〈strong〉CTB〈/strong〉) has been successfully designed and synthesized through exploiting tris-(2-aminothyl)-amine moiety as a recognition unit for the highly selective and sensitive detection of Cd〈sup〉2+〈/sup〉. It is based on C〈img src="https://sdfestaticassets-eu-west-1.sciencedirectassets.com/shared-assets/16/entities/dbnd"〉N isomerization and the photo-induced electron transfer (PET) mechanism. The investigation into the sensing processes showed that 〈strong〉CTB〈/strong〉 exhibited an excellent selectivity for Cd〈sup〉2+〈/sup〉. The sensitivity exceeded that of other competing metal ions, and had a high sensitivity, a detection limit of 1.16 × 10〈sup〉−7〈/sup〉 M with the association constants of 1.37 × 10〈sup〉11〈/sup〉 M〈sup〉−2〈/sup〉. The experiments including Job's plot, UV–Vis titration, 〈sup〉1〈/sup〉H NMR titration and ESI-MS spectrum established that the probe 〈strong〉CTB〈/strong〉 binds to Cd〈sup〉2+〈/sup〉 in a 1:2 ratio. Further studies also demonstrated that probe 〈strong〉CTB〈/strong〉 can be successfully applied to the fluorescence imaging of Cd〈sup〉2+〈/sup〉 in HepG-2 cells.〈/p〉〈/div〉 〈/div〉 〈div xml:lang="en"〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S138614251930352X-ga1.jpg" width="500" alt="Unlabelled Image" title="Unlabelled Image"〉〈/figure〉〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: Available online 28 March 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy〈/p〉 〈p〉Author(s): Vladimir Ivanovski, Thomas G. Mayerhöfer, Jernej Stare, Marta Klanjšek Gunde, Jože Grdadolnik〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉In contrast to the extensive molecular and crystal structure investigations on oxalic acid dihydrate (C〈sub〉2〈/sub〉H〈sub〉2〈/sub〉O〈sub〉4〈/sub〉·2H〈sub〉2〈/sub〉O, α-POX) and its deuterated analogues (α-DOX), stands the absence of a complete vibrational spectra analysis. Such analysis is desirable in view of the proton dynamics in α-POX crystals. In this communication we report the room temperature polarized IR reflectance spectra of a single crystal of α-POX recorded from the 〈em〉ac〈/em〉 crystal plane, and from the plane containing the 〈em〉b〈/em〉-crystallographic axis, with polarization along the axis. Dispersion analysis of the reflectance spectra of both 〈em〉B〈/em〉〈sub〉u〈/sub〉 and 〈em〉A〈/em〉〈sub〉u〈/sub〉 symmetry type modes, using model dielectric and reflectance function valid for the monoclinic case, have been performed and the results are discussed. Some aspects of the obtained fit results for some of the spectral regions and the peculiar change of the reflectance function with polarization angle are also discussed in this work. A correlation between the crystal structure and measured spectra, together with the results of the performed dispersion analysis, gave answers to some of the problems concerned with the orientation of the transition dipole moments of the IR active modes. The assignment of modes is assisted by DFT calculations. Another aspect covered in this work is the model reflectance functions using different averaging theories that have been applied in obtaining the reflectance spectrum of a polycrystalline sample. The results of the comparison between these spectra and the recorded reflectance spectra from a polycrystalline sample were further discussed.〈/p〉〈/div〉 〈/div〉 〈div xml:lang="en"〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S1386142519303427-ga1.jpg" width="245" alt="Unlabelled Image" title="Unlabelled Image"〉〈/figure〉〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: Available online 27 March 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy〈/p〉 〈p〉Author(s): Shanshan Tang, Lin Du〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉In order to explore the effect of methylation on the stability and spectral shift of hydrogen bond complexes, the complexes of 2,2,2-trifluoroethanol (TFE) with propylene oxide (PO) and isobutylene oxide (IBO) were investigated by Fourier transform infrared (FTIR) spectroscopy and ab initio computations. The comparable OH-stretching red shifts were observed upon complexation, and an enhancement of the OH-stretching band is shown with the partial pressure of monomers increasing. The OH-stretching frequency of TFE is red shifted by 180 and 201 cm〈sup〉−1〈/sup〉 with PO and IBO, respectively. By using quantum chemical calculations, we predicted the geometric parameters, binding energies, and spectral shifts of TFE〈img src="https://sdfestaticassets-eu-west-1.sciencedirectassets.com/shared-assets/16/entities/sbnd"〉PO/IBO hydrogen bond complexes. The calculated and observed spectral shifts follow the same trends. Compared with the TFE〈img src="https://sdfestaticassets-eu-west-1.sciencedirectassets.com/shared-assets/16/entities/sbnd"〉ethylene oxide (EO) complex, the strength of the hydrogen bond in complex increases with the addition of methyl group, which likely results from the increase in basicity of the hydrogen bond acceptor. By combining the experimental integrated absorbance and the calculated IR intensity of the OH-stretching vibrational transition, the equilibrium constant for the complex formation was determined. In addition, atoms-in-molecules (AIM) and natural bond orbital (NBO) analyses were carried out to explain the red shift and the nature of the interaction in these complexes.〈/p〉〈/div〉 〈/div〉 〈div xml:lang="en"〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S1386142519303361-ga1.jpg" width="273" alt="Unlabelled Image" title="Unlabelled Image"〉〈/figure〉〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: Available online 27 March 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy〈/p〉 〈p〉Author(s): Jian-Jun Li, Dan Qiao, Jing Zhao, Guo-Jun Weng, Jian Zhu, Jun-Wu Zhao〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The applications of metallic nanoclusters and nanoparticles in biological sensing have attracted special attention owing to their optical interaction based on fluorescence and surface plasmon resonance (SPR). In this work, we designed a fluorescent nanoprobe for the determination of 〈em〉L〈/em〉-cysteine (〈em〉L〈/em〉-Cys) based on fluorescence resonance energy transfer (FRET) from gold‑silver bimetallic nanoclusters (Au-Ag NCs) to gold nanorods (AuNRs). Firstly, the negatively charged Au-Ag NCs protected by bovine serum albumin (BSA) are directly adsorbed on the surface of the positively charged AuNRs through electrostatic interaction, and the FRET effect leads to distinct fluorescence quenching of Au-Ag NCs at 615 nm. The SPR wavelength of AuNRs is dependent on the aspect ratio, so the SPR of AuNRs could be tuned to have a better spectral overlap with fluorescence of Au-Ag NCs, which enhances the fluorescence quenching effect. Because the 〈img src="https://sdfestaticassets-eu-west-1.sciencedirectassets.com/shared-assets/16/entities/sbnd"〉SH group of 〈em〉L〈/em〉-Cys has an affinity with gold, the addition of 〈em〉L〈/em〉-Cys can result in the release of Au-Ag NCs from the surface of AuNRs via forming Au〈img src="https://sdfestaticassets-eu-west-1.sciencedirectassets.com/shared-assets/16/entities/sbnd"〉S bonds. Thus, the introduction of 〈em〉L〈/em〉-Cys could effectively restore the fluorescence emission of the AuNRs/Au-Ag NCs system because of the restraint of FRET effect. Under the optimized conditions, the fluorescence recovery of AuNRs/Au-Ag NCs probe exhibits a linear response to 〈em〉L〈/em〉-Cys concentration ranging from 5 to 100 μM, and the corresponding theoretical detection limit (LOD) is 1.73 μM. Meanwhile, this method displays excellent sensitivity and selectivity for 〈em〉L〈/em〉-Cys over other amino acids, and it has been successfully applied to detect 〈em〉L〈/em〉-Cys in real samples.〈/p〉〈/div〉 〈/div〉 〈div xml:lang="en"〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S1386142519303403-ga1.jpg" width="500" alt="Unlabelled Image" title="Unlabelled Image"〉〈/figure〉〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 15 June 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 217〈/p〉 〈p〉Author(s): Huinan Yang, Chengfang Luo, Chengxing Shen, Huirong Ding, Bo Wu, Xiaoshu Cai〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The morbidity of coronary heart disease (CHD) with high risks has been rising in recent years. A novel and noninvasive method based on surface-enhanced Raman spectroscopy (SERS) was proposed by Yang et al. (Analyst 143: 2235, 2018) to prospectively diagnose the arterial blockage by detecting platelet-derived growth factor-BB (PDGF-BB) in urine. Clinically, anti-platelet drugs (such as aspirin, statins and clopidogrel) are often used for ordinary CHD patients or patients with percutaneous coronary intervention (PCI). Therefore, whether the previous developed method can be applied to the CHD patients on long-term medication (more than 6 months) or post-PCI patients was investigated here. Firstly, urine samples of 13 CHD patients on long-term medication (aspirin, rosuvastatin, clopidogrel bisulfate) and 13 post-PCI patients were measured by the proposed method. Clinical data of coronary angiography results provided by Xin Hua Hospital and Yangpu District Central Hospital Antu Branch revealed that these 26 patients were with serious arterial blockage, however, characteristic Raman peak at 1509 cm〈sup〉−1〈/sup〉 attributed to PDGF-BB was not observed in the SERS spectra of these 26 patients. In addition, an eight-day follow-up investigation was performed on a CHD patient with PCI three years ago and on long-term medication. It was found that the Raman peak at 1509 cm〈sup〉−1〈/sup〉 could be only observed in the third and fourth day after suspending the drugs. Furthermore, SERS spectra of mixed solutions of PDGF-BB and aspirin, rosuvastatin, mixed solutions of these two drugs and clopidogrel bisulfate were analyzed. The Raman peak at 1509 cm〈sup〉−1〈/sup〉 was not found in all these spectra, it indicated that all the three kinds of drugs could influence on the SERS signal of PDGF-BB. Therefore, the previous developed method is not suitable for CHD patients on long-term medication and post-PCI patients.〈/p〉〈/div〉 〈/div〉 〈div xml:lang="en"〉 〈h5〉Graphical Abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S138614251930335X-ga1.jpg" width="301" alt="Unlabelled Image" title="Unlabelled Image"〉〈/figure〉〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 15 June 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 217〈/p〉 〈p〉Author(s): Xiongjie Lin, Danting Tang, Tian He, Zheng Xu, Huayu Qiu, Qian Zhang, Shouchun Yin〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉A series of 4,4-difluoro-4-bora-3〈em〉a〈/em〉,4〈em〉a〈/em〉-diaza-s-indacene (BODIPY) with different connection sites and conjugation length and fluorene alternating conjugated polymers have been synthesized via palladium-catalyzed Suzuki coupling reaction. The polymers were fully characterized by 〈sup〉1〈/sup〉H NMR spectroscopy and gel permeation chromatography (GPC), and their properties were measured by thermogravimetric analysis (TGA), UV–vis absorption spectroscopy, cyclic voltammetry (CV), photoluminescence (PL) spectroscopy, the 〈em〉Z〈/em〉-scan technique, and theoretical calculation using density-functional theory (DFT) method. The results indicate that the connection sites and conjugation length of BODIPY have great effect on the optical-electronic and nonlinear optical properties of the conjugated BODIPY- fluorene copolymers although they don't affect the polymerization process. The absorption and emission peaks of 〈strong〉P1〈/strong〉 exhibit red shifts compared to those of 〈strong〉P2〈/strong〉 and 〈strong〉P3〈/strong〉. The polymers show good nonlinear optical properties that are closely related to the connection sites of the BODIPY pendants. 〈strong〉P1〈/strong〉 exhibits relatively richer nonlinear optical (NLO) properties than 〈strong〉P2〈/strong〉 and 〈strong〉P3〈/strong〉. The third order nonlinear optical coefficient (χ〈sup〉(3)〈/sup〉) of 〈strong〉P1〈/strong〉 is 3.57 × 10〈sup〉−11〈/sup〉 esu, which is ~4 times larger than those of 〈strong〉P2〈/strong〉 and 〈strong〉P3〈/strong〉.〈/p〉〈/div〉 〈/div〉 〈div xml:lang="en"〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S1386142519303312-ga1.jpg" width="500" alt="Unlabelled Image" title="Unlabelled Image"〉〈/figure〉〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 5 June 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 216〈/p〉 〈p〉Author(s): Xia Lu, Zhefeng Fan〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉An easy, dependable, and sensitive cholic acid activity experiment was designed based on β‑cyclodextrin-modified carbon dot (β‑CD-CD) nanoprobes with specific host–guest recognizing ability and photoelectron transfer capability. The β‑CD-CD nanoprobes were characterized by infrared, ultraviolet-visible, and fluorescence spectroscopy and transmission electron microscopy. The fluorescence of the probes under optimized conditions linearly responded to cholic acid concentration from 0 to 650 μmol·L〈sup〉−1〈/sup〉 with a detection limit of 25 nmol·L〈sup〉−1〈/sup〉. The probes also performed well in detecting cholic acid in serum and urine samples with an average recovery rate of 97.1%–103.4%. Thus, this study provides a reliable, rapid, and easy method of cholic acid detection in body fluids that can be potentially applied in medical studies.〈/p〉〈/div〉 〈/div〉 〈div xml:lang="en"〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S138614251930304X-ga1.jpg" width="385" alt="Unlabelled Image" title="Unlabelled Image"〉〈/figure〉〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: Available online 29 March 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy〈/p〉 〈p〉Author(s): Yan Jin, Xiaolong Li, Yang Zheng, Qian Gou, Zhining Xia, Gang Feng〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉2-chlorothiophene and its van der Waals complex with argon were studied by supersonic-jet Fourier transform microwave spectroscopy. Rotational measurements of parent and the mono-substituted 〈sup〉37〈/sup〉Cl, 〈sup〉34〈/sup〉S and 〈sup〉13〈/sup〉C isotopologues of the monomer allowed its precisely structural determination. Rotational spectra of 〈sup〉35〈/sup〉Cl and 〈sup〉37〈/sup〉Cl isotopologues were observed and assigned for the van der Waals complex of 2-chlorothiophene with Ar. 〈em〉Ab initio〈/em〉 calculations carried out at the MP2/6-311++G(d,p) level of theory complement the experimental studies. Spectroscopic and theoretical results support a conformation in which the Ar atom locates above the plane of aromatic ring and toward the substituted carbon atom. The distance between the centers of mass of 2-chlorothiophene and argon is 3.589 Å. The Non-Covalent Interaction analysis and Symmetry-Adapted Perturbation theory were performed to reveal the nature of the non-covalent interaction within the complex.〈/p〉〈/div〉 〈/div〉 〈div xml:lang="en"〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S138614251930349X-ga1.jpg" width="500" alt="Unlabelled Image" title="Unlabelled Image"〉〈/figure〉〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: Available online 29 March 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy〈/p〉 〈p〉Author(s): Nathália de A. Porto, Jussara V. Roque, Cleiton A. Wartha, Wilson Cardoso, Luiz A. Peternelli, Márcio H.P. Barbosa, Reinaldo F. Teófilo〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The aim of this work was to use spectroscopic methods and partial least squares discriminant analysis (PLS-DA) for the early prediction of genotype resistance or susceptibility to sugarcane borer. The sugarcane leaf +1 was directly analyzed with no sample preparation by ultraviolet-visible-near-infrared (UV-VIS-NIR), middle-infrared (MID), and near-infrared (NIR) spectroscopies. Also, laser-induced breakdown spectroscopy (LIBS) was used to analyze pellets of dried and ground leaves and stalks of sugarcane. Classification models were built using PLS-DA. The models built using UV-VIS-NIR, MID or NIR spectra exhibited ideal sensitivity, specificity, and classification errors, i.e., 1 for both sensitivity and specificity and 0 for classification errors. Regarding the models built using LIBS spectra, those using spectra of pellets made from dried and ground leaves also presented ideal sensitivity, specificity, and classification errors; on the other hand, models built using the spectra of pellets made of dried and ground stalks did not present ideal values for these parameters. Thus, the models built, except for the one using LIBS of pellets made of stalks, showed excellent predictive capacity, making them suitable for predicting the resistance or susceptibility of sugarcane genotypes in the early stages of a plant's life.〈/p〉〈/div〉 〈/div〉 〈div xml:lang="en"〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S1386142519303622-ga1.jpg" width="458" alt="Unlabelled Image" title="Unlabelled Image"〉〈/figure〉〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: Available online 29 March 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy〈/p〉 〈p〉Author(s): Waleed A. El-Said, Jeong-woo Choi〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Hepatitis C virus (HCV) is a blood-borne virus that causes infectious chronic hepatitis. Egypt has the largest epidemic of HCV in the world, with about 14.7% of the Egyptian population. Thus, HCV, which could cause severe risks for human health including liver failure, becomes a public health concern for Egyptians. Development of highly selective and sensitive biosensors for accurate detection of HCV levels without extensive sample preparation has received great attention. The present work reported on developing a new rapid, highly selective and highly selective HCV-based biosensor for early detection of HCV-RNA extracted from clinical samples. The HCV-based biosensor was constructed by fabrication of gold nanodots/indium tin oxide substrate and followed by immobilization of a specific peptide nucleic acid (as bio-receptors) terminated with thiol group onto gold nanodots/indium tin oxide. The principle of the developed biosensor was based on the selective hybridization between the peptide nucleic acid and the HCV-RNA at the untranslated regions (5′-UTR). Raman spectroscopy and Square wave voltammetry techniques were used to monitor the interaction between the HCV-RNA and the immobilized peptide nucleic acid. The reported HCV-biosensor demonstrated a high capability to detect HCV-RNA.〈/p〉〈/div〉 〈/div〉 〈div xml:lang="en"〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S1386142519303634-ga1.jpg" width="397" alt="Unlabelled Image" title="Unlabelled Image"〉〈/figure〉〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: Available online 29 March 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy〈/p〉 〈p〉Author(s): Xuesong Liu, Siyu Zhang, Hongfei Ni, Wei Xiao, Jun Wang, Yerui Li, Yongjiang Wu〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Characteristic variables are essential and necessary basis in model construction, and are related to the prediction result closely in near infrared spectroscopy (NIRS) analysis. However, the same compound usually has different characteristic variables for different analysis and it would be lower correlation between variables and structure in many researches. So, the accuracy and reliability are expected to improve by exploring characteristic variables in different spectrum analysis. In this study, competitive adaptive weighted resampling method (CARS) was applied to select characteristic variables related to baicalin from NIRS analysis data, which were applied to analysis of baicalin in three different processes including the herb, extraction process and concentration process of 〈em〉Scutellaria baicalensis〈/em〉. After application of CARS method, 70, 50 and 50 variables were selected respectively from three processes above. The selected variables were firstly analyzed by statistical methods that they were found to be consistent and correlated among three different processes after one-way analysis of variance test and Kendall's W. Partial least-squares (PLS) regression and extreme learning machine (ELM) models were constructed based on optimized data. Models after variable selection were less complicated and had better prediction results than global models. After comparison, CARS-PLS was suitable for the prediction of extraction process, while for the concentration process and herb, CARS-ELM performed better. The Rc value of the herb, extraction and concentration model were 0.9469, 0.9841 and 0.9675, respectively. The RSEP values were 4.54%, 6.96% and 8.37%, respectively. The results help to frame a theoretical basis for characteristic variables of baicalin.〈/p〉〈/div〉 〈/div〉 〈div xml:lang="en"〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S1386142519303609-ga1.jpg" width="301" alt="Unlabelled Image" title="Unlabelled Image"〉〈/figure〉〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: Available online 25 March 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy〈/p〉 〈p〉Author(s): Hatem Besrour, Bahoueddine Tangour, Roberto Linguerri, Majdi Hochlaf〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉By using first-principles approaches based on Density Functional Theory, we explore the possibility of using dendritic macromolecular structures as carriers of the doxorubicin anticancer drug. In particular, we consider macromolecular cavities of different sizes composed of phenylene-, thiophene-, phenyl-cored thiophen- and thioazole-based dendrimers. The comparison between the optimized molecular geometries of the monomers and of the host-guest complexes reveals that only slight structural changes are observed in doxorubicin upon complexation. Also, the encapsulation energies for the host-guest complexes suggest that these systems are of potential use for pharmacology applications in vivo. The interaction of the guest doxorubicin with the macromolecular cavities exploits different types of weak intermolecular forces including σ, π and hydrogen bond interactions. The electronic structure of these complexes is discussed, with particular emphasis placed on the role of the charge distribution and the nature of the frontier molecular orbitals in the encapsulation process. Spectroscopic properties of these complexes are derived to facilitate their detection in laboratory and in vivo. These include IR vibrational frequencies, absorption wavelengths and relative oscillator strengths for the main transitions in the UV–Vis spectrum.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 15 June 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 217〈/p〉 〈p〉Author(s): A. Poursoleiman, M.H. Karimi-Jafari, Z. Zolmajd-Haghighi, M. Bagheri, T. Haertlé, G. Rezaei Behbehani, A. Ghasemi, Y.Y. Stroylova, V.I. Muronetz, A.A. Saboury〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Polymyxin B and E (colistin), are a group of cationic charged cyclic antibiotic lipopeptides that are frequently used in the clinics to treat infections caused by the multidrug-resistant gram-negative bacteria. Since the interactions with the blood plasma drug-transport proteins may play a critical role in determining their pharmacological and pharmacokinetic profiles, we studied the binding properties of polymyxins to the human serum albumin (HSA) under simulated physiological conditions by the combination of biophysical approaches, such as isothermal titration calorimetry (ITC), fluorescence anisotropy, circular dichroism (CD) buttressed by computational studies. The HSA binding to the polymyxins was relatively strong (K〈sub〉a〈/sub〉 ≈ 1.0 × 10〈sup〉7〈/sup〉 M〈sup〉−1〈/sup〉). Molecular docking indicated that polymyxins bind to the cleft of HSA between domains I and III via the electrostatic interactions. This evidence was further confirmed by the entropy-driven interaction for the polymyxins bound HSA. Far UV-CD experiments showed that the secondary structure of HSA doesn't alter and its stable structure is preserved. Collectively, these investigations revealed that the polymyxins bind preferentially to the partially unfolded intermediate forms of the protein structure; however, HSA molecule does not undergo any significant conformational changes upon binding. This is promising as it may limit the unfavorable side effects of the medicine. On the whole, the results provide quantitative and qualitative insight of the binding interaction between HSA and polymyxins, which is important in understanding their effect as therapeutic agents.〈/p〉〈/div〉 〈/div〉 〈div xml:lang="en"〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S1386142519303257-ga1.jpg" width="500" alt="Unlabelled Image" title="Unlabelled Image"〉〈/figure〉〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 15 June 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 217〈/p〉 〈p〉Author(s): Gohar A. Shahinyan, Aren Yu. Amirbekyan, Shiraz A. Markarian〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉A detailed study of the effect of aprotic polar solvents such as dimethylsulfoxide on methylene blue (MB) was carried out through a combination of UV–vis absorption and steady-state fluorescence spectroscopy techniques at 293.15 K. In aqueous solutions MB tends to exhibit strong tendency to aggregate. The dimerization behavior of MB in water was analyzed in terms of monomer-dimer equilibrium. The addition of dimethylsulfoxide prevents dimerization of dye molecules. From absorption spectra the dimerization constants and changes of standard Gibbs energy were calculated. From the steady-state fluorescence spectra the quantum yields and Stokes shifts were determined. To explain the effect of dimethylsulfoxide properly the other polar aprotic solvents such as 〈em〉N〈/em〉, 〈em〉N〈/em〉-dimethylformamide, acetonitrile and acetone were used. It is suggested that water structural effect is the major factor in aggregation phenomenon. Moreover the quantum yield increases drastically in dimethylsulfoxide compared with water assuming that MB may be characterized as viscosity probe.〈/p〉〈/div〉 〈/div〉 〈div xml:lang="en"〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S1386142519303269-ga1.jpg" width="275" alt="Unlabelled Image" title="Unlabelled Image"〉〈/figure〉〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 15 June 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 217〈/p〉 〈p〉Author(s): Mahmoud A. Omar, Mohamed A. Hammad, Mohamed Awad〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉A simple selective luminescent dependent approach was established for quantitation of two selective β〈sub〉2〈/sub〉 agonists namely; Fenoterol hydrobromide (FEN) and Salmeterol xinafoate (SAL). This approach utilizes the capability of the cited drugs to undergo a complexation reaction with Europium ion (Eu〈sup〉3+〈/sup〉) in the presence of 1,10-phenanthroline as a co-ligand. The resultant complex leads to a hypersensitive transition and enhancement of the Eu〈sup〉3+〈/sup〉 emission peak at 615 nm (279 nm excitation). Under the optimized conditions, the rectilinear concentration plots of both drugs were (70–1500 ng mL〈sup〉−1〈/sup〉) and (100–2000 ng mL〈sup〉−1〈/sup〉) with limit of quantitation 51.3 and 84.4 ng mL〈sup〉−1〈/sup〉 for FEN and SAL, respectively. The luminescence properties of the complex and its optimum formation conditions were carefully investigated according to the regulations of ICH and the method was successfully applied in plasma. The good accuracy and selectivity of the suggested method allowed extending the proposed protocol into stability study of the cited drugs.〈/p〉〈/div〉 〈/div〉 〈div xml:lang="en"〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉Suggested reaction mechanism between Fenoterol hydrobromide as a representative example and Eu〈sup〉3+〈/sup〉 in presence of 1,10-phenanthroline.〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S1386142519303105-ga1.jpg" width="301" alt="Unlabelled Image" title="Unlabelled Image"〉〈/figure〉〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: Available online 28 March 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy〈/p〉 〈p〉Author(s): Junning Qian, Di Wu, Ping Cai, Jiangbin Xia〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉A new nitrogen atom free polythiophene derivative bearing methoxy-ethoxy units of poly{3-[2-(2-methoxy-ethoxy)-ethoxy]-thiophene} (PM) was successfully synthesized by introducing multiple ether bonds on the thiophene unit. The special (ether bonds) coordination structure was constructed and these fluorescence characteristics of PM to metal ions detection were investigated. This polythiophene-based material displays a specific fluorescence quenching effect on Cu〈sup〉2+〈/sup〉 and Ag〈sup〉+〈/sup〉, and correspondingly emerges some color changes that are visible to the naked eyes. In addition, it even performs a low detection limit to Cu〈sup〉2+〈/sup〉 for only 0.45 μM, which exhibits a higher selective detection to Cu〈sup〉2+〈/sup〉 than other reported N-containing chemosenors. These discoveries are helpful to indicate an original aspect for development on nitrogen atom free polythiophene-based fluorescent-sensing materials.〈/p〉〈/div〉 〈/div〉 〈div xml:lang="en"〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S1386142519303415-ga1.jpg" width="424" alt="Unlabelled Image" title="Unlabelled Image"〉〈/figure〉〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: Available online 27 March 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy〈/p〉 〈p〉Author(s): Yujia Xu, Taotao Dai, Ti Li, Kechou Huang, Yuting Li, Chengmei Liu, Jun Chen〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The interaction between plant protein and polyphenol is a topic of considerable interest. However, there is relatively little understanding about the interaction between rice protein and epigallocatechin-3-gallate (EGCG). The spectroscopy and computational docking program were used to investigate the potential interaction between rice glutelin (RG) and EGCG. It was found that the intrinsic fluorescence of RG could be quenched by EGCG, which indicated interaction occurred between them. Thermodynamic analysis elucidated that the interaction process between RG and EGCG happened spontaneously with hydrogen bond as the primary driving force. The ANS-fluorescence indicated that the surface hydrophobicity of RG reduced with the increasing of EGCG. Circular dichroism spectra and synchronous fluorescence gave further information for the conformational and microenvironmental changes of RG. Particularly, the α-helix structure reduced and random coil structure increased after the binding interaction. Furthermore, the computational docking program exhibited target sites in which the amino acid residues of RG and EGCG might be bound together.〈/p〉〈/div〉 〈/div〉 〈div xml:lang="en"〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S1386142519303397-ga1.jpg" width="301" alt="Unlabelled Image" title="Unlabelled Image"〉〈/figure〉〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 5 April 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 212〈/p〉 〈p〉Author(s): Sun Jun, Zhou Xin, Wu Xiaohong, Lu Bing, Dai Chunxia, Shen Jifeng〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The reliability and validity of Vis-NIR hyperspectral imaging were investigated for the determination of heavy metal content in tomato leaves under different cadmium stress. Besides, a method involving wavelet transform and least square support vector machine regression (WT-LSSVR) is proposed to select the optimal wavelength and establish the detection model. The Vis-NIR hyperspectral images of 405 tomato leaf samples were obtained and the whole region of tomato leaf sample spectral data was collected and preprocessed. In addition, WT-LSSVR is used to select optimal wavelength and establish the detection model using db4 and db6 as wavelet basis function, respectively. Furthermore, the best prediction performances for detecting cadmium (Cd) content in tomato leaves was obtained by second derivative (2nd Der) pre-processing method, with R〈sub〉c〈/sub〉〈sup〉2〈/sup〉 of 0.9437, RMSEC of 0.0988 mg/kg, R〈sub〉p〈/sub〉〈sup〉2〈/sup〉 of 0.8937, RMSEP of 0.2331 mg/kg, R〈sub〉cv〈/sub〉〈sup〉2〈/sup〉 of 0.9357, RMSECV of 0.1455 mg/kg, RPD of 3.081 and bias of 0.00863 using db6 (daubechies 6) as wavelet basis function with wavelet fourth layer decomposition. The results of this study indicated that WT-LSSVR can effectively select the optimal wavelength and Vis-NIR hyperspectral imaging has great potential for detecting heavy metal content in tomato leaves under different cadmium stresses.〈/p〉〈/div〉 〈/div〉 〈div xml:lang="en"〉 〈h5〉Graphical Abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S1386142518311211-ga1.jpg" width="324" alt="Unlabelled Image" title="Unlabelled Image"〉〈/figure〉〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 5 April 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 212〈/p〉 〈p〉Author(s): G.P. Sheeja Mol, D. Aruldhas, I. Hubert Joe, S. Balachandran, A. Ronaldo Anuf, Jesby George, Anuroopa G. Nadh〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The main objective of the study is to analyze the structural behaviour and fungicidal activity of clotrimazole by experimental and theoretical spectroscopic techniques. Its computational results are correlated with three triphenyl imidazole derivative compounds. The clotrimazole-water complexes formed by hydrogen bonding interactions are investigated at the B3LYP/6-311G(d,p) level. The distributions of the vibrational bands are carried out with the help of normal coordinate analysis (NCA). Hirshfeld surface analysis of clotrimazole is done and the obtained finger print plots reveal the interactions within the compound. The stability of the compounds in water has been investigated by using molecular dynamics simulation (MDS). Molecular docking is done on the compounds in comparison with the native ligand (Lanosterol 14α-demethylase) and standard drug (fluconazole) to study the hydrogen bond energy interaction. The antifungal activity of clotrimazole is analyzed by using two fungal pathogens.〈/p〉〈/div〉 〈/div〉 〈div xml:lang="en"〉 〈h5〉Graphical Abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S138614251831117X-ga1.jpg" width="301" alt="Unlabelled Image" title="Unlabelled Image"〉〈/figure〉〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 5 April 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 212〈/p〉 〈p〉Author(s): Manish Kumar, Gyanendra Kumar, Navin Kumar Mogha, Ritu Jain, Firasat Hussain, Dhanraj T. Masram〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉This work presents the synthesis, structural characterization and biological affinity of the newly synthesized copper(II) complexes with the first antibacterial quinolone drug nalidixic acid (nal) or N–donor ligand 2,2′‑dipyridylamine (bipyam). [Cu(II)(nal)(bipyam)Cl], (〈strong〉2〈/strong〉) reveals a distorted square pyramidal based geometry in Cu(II) atom confirmed by X-ray crystallography technique. The theoretical stabilities and optimized structures of the complex were obtained from DFT calculations. The ability of the complexes to bind with calf thymus DNA (〈strong〉CT DNA〈/strong〉) were investigated by electronic absorption, fluorescence, circular dichroism, and viscosity measurements techniques. The experimental results reveal that the complexes strongly interact with CT DNA 〈em〉via〈/em〉 intercalative mode but complex 〈strong〉2〈/strong〉 exhibits the highest affinity giving 〈strong〉〈em〉K〈/em〉〈/strong〉〈sub〉〈strong〉〈em〉b〈/em〉〈/strong〉〈/sub〉 = 〈strong〉3〈/strong〉.〈strong〉91〈/strong〉 ± 〈strong〉0〈/strong〉.〈strong〉13〈/strong〉 × 〈strong〉10〈/strong〉〈sup〉〈strong〉6〈/strong〉〈/sup〉, 〈strong〉M〈/strong〉〈sup〉−〈strong〉1〈/strong〉〈/sup〉. The fluorescence spectroscopy measurements show that both complexes have the superior ability to the replacement of EtBr from DNA-bound EtBr solution and bind to DNA through intercalative mode. Both complex also shows the superior affinity towards proteins with comparatively high binding constant values which have been further revealed by fluorescence spectroscopy measurements. Molecular docking analysis indicates that the interaction of the complexes and proteins are stabilized by hydrogen bonding and hydrophobic interaction. Furthermore, the results of 〈em〉in vitro〈/em〉 cytotoxicity reveal that the complex 〈strong〉2〈/strong〉 has excellent cytotoxicity than 〈strong〉1〈/strong〉 against human breast cancer cell lines (MCF-7).〈/p〉〈/div〉 〈/div〉 〈div xml:lang="en"〉 〈h5〉Graphical Abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S1386142518311156-ga1.jpg" width="337" alt="Unlabelled Image" title="Unlabelled Image"〉〈/figure〉〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 5 April 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 212〈/p〉 〈p〉Author(s): Fatemeh Sabzehparvar, Tavoos Rahmani Cherati, Afshin Mohsenifar, Taha Roodbar Shojaei, Meisam Tabatabaei〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Infectious bursal disease virus is a causative agent of one of the most important disease which causes frequent tragic disaster in the poultry industry all over the world. Therefore, in the present study a new fluorescence resonance energy transfer-based technique was developed to detect VP2 gene of infectious bursal disease virus using two oligonucleotide probes labeled with quantum dots and rhodamine- immobilized gold nanoparticles (AuNPs-Rh). Quantum dots labeled with an amino-modified first oligonucleotide, and AuNPs-Rh labeled with thiol-modified second oligonucleotides were added to the DNA targets upon which hybridization occurred. In the presence of target the AuNPs-Rh will be located in the vicinity of the quantum dots and leads to the fluorescence resonance energy transfer to be occurred and subsequently the fluorescence intensity of quantum dots was stimulated. The immobilization of rhodamine to the surface of AuNPs increased the fluorescence intensity of rhodamine. The maximum fluorescence resonance energy transfer efficiency for the developed sensor is monitored at a quantum dots-P〈sub〉A〈/sub〉/AuNPs-Rh-P〈sub〉T〈/sub〉 molar ratio of 1:10. Moreover, the feasibility of the developed nanobiosensor was demonstrated by the detection of a synthetic 49-mer nucleotide derived from infectious bursal disease virus and the limit of detection was estimated as 3 × 10〈sup〉−8〈/sup〉 M. The developed DNA detection scheme is a simple, rapid and efficient technique which does not need excessive washing and separation steps.〈/p〉〈/div〉 〈/div〉 〈div xml:lang="en"〉 〈h5〉Graphical Abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S138614251831120X-ga1.jpg" width="273" alt="Unlabelled Image" title="Unlabelled Image"〉〈/figure〉〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 5 April 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 212〈/p〉 〈p〉Author(s): Hiroshi Abe, Tsukasa Tokita, Koichi Iwata, Shinichiro Ozawa〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉In this study, the effect of alcohol on polyiodide formation in room-temperature ionic liquid (RTIL) was examined by time evolutions of Raman spectra in the low-frequency region and by color changes of the sample. The RTIL was 1-methyl-3-propylimidazolium iodide, [C〈sub〉3〈/sub〉mim][I]. Polyiodides develop in [C〈sub〉3〈/sub〉mim][I]‑lithium salt-ethanol solutions (Abe et al., 〈em〉Chem. Phys〈/em〉. 502 (2018) 72.). Without the external addition of iodine or without an external electric field, the irreversible transformation from I〈sup〉−〈/sup〉 to I〈sub〉3〈/sub〉〈sup〉−〈/sup〉 indicates that charge unbalancing was promoted by lithium ion. Polyiodide formations were not induced by sodium or potassium ions. Strong alcohol effects were observed directly by the time-dependent Raman bands in the low-frequency region.〈/p〉〈/div〉 〈/div〉 〈div xml:lang="en"〉 〈h5〉Graphical Abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S1386142518311193-ga1.jpg" width="479" alt="Unlabelled Image" title="Unlabelled Image"〉〈/figure〉〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 5 April 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 212〈/p〉 〈p〉Author(s): Yongdeng Feng, Xiaohua Liu, Shuai Ma, Fangfang Wang, Lifeng Tan〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The interaction of [Ru(phen)〈sub〉2〈/sub〉dppz-idzo]〈sup〉2+〈/sup〉 (phen = 1,10-phenanthroline, dppz-idzo = dppz-imidazolone) with triplex RNA poly(U)·poly(A)*poly(U) was carried out by using spectroscopic and viscometric techniques in this work. Luminescent titrations suggest that [Ru(phen)〈sub〉2〈/sub〉dppz-idzo]〈sup〉2+〈/sup〉 shows better selectivity for poly(U)·poly(A)*poly(U) compared with poly(U)·poly(A) and poly(U), this complex exhibits a “light switch” effect with an emission enhancement factor of about 123 in the presence of poly(U)·poly(A)*poly(U). Significantly, this “light switch” behavior could even be observed by the naked eye under irradiation with UV light. To our knowledge, [Ru(bpy)〈sub〉2〈/sub〉dppz-idzo]〈sup〉2+〈/sup〉 is the first small molecule able to serve as a colorimetric molecular “light switch” for the triplex poly(U)·poly(A)*poly(U). Combined with the spectral and viscometric results as well as [Ru(phen)〈sub〉2〈/sub〉dppz-idzo]〈sup〉2+〈/sup〉 stabilizing the template duplex poly(U)·poly(A), we speculate that [Ru(phen)〈sub〉2〈/sub〉dppz-idzo]〈sup〉2+〈/sup〉 prefers to bind with the Hoogsteen base-paired strand (the third strand) of the triplex, thus the intercalating [Ru(phen)〈sub〉2〈/sub〉dppz-idzo]〈sup〉2+〈/sup〉 stabilizing the third strand is more marked in comparison with the Watson-Crick base-paired duplex of the triplex. The results obtained here may be useful for understanding the interaction of triplex RNA poly(U)·poly(A)*poly(U) with small molecule, particularly ruthenium(II) complexes.〈/p〉〈/div〉 〈/div〉 〈div xml:lang="en"〉 〈h5〉Graphical Abstract〈/h5〉 〈div〉〈p〉The present study reveals that [Ru(phen)〈sub〉2〈/sub〉dppz-idzo]〈sup〉2+〈/sup〉 exhibits stronger binding with the Hoogsteen base-paired strand than to the Watson-Crick base-paired duplex of the RAN triplex poly(U)·poly(A)*poly(U), thereby stabilizing the Hoogsteen base-paired strand more effectively under the same conditions. Viscometric experiments reveals that the binding mode of [Ru(phen)〈sub〉2〈/sub〉dppz-idzo]〈sup〉2+〈/sup〉 toward the RNA triple is intercalation. The fluorescence titrations indicate that [Ru(phen)〈sub〉2〈/sub〉dppz-idzo]〈sup〉2+〈/sup〉 is able to serve as a colorimetric molecular “light switch” for the RNA triplex. CD titrations indicate that [Ru(phen)〈sub〉2〈/sub〉dppz-idzo]〈sup〉2+〈/sup〉 can induce significant conformational perturbations of the RNA triplex. The present results further offer valuable information on the interaction of the RNA triplex with small molecules, particularly ruthenium(II) complexes.〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S1386142518311181-ga1.jpg" width="345" alt="Unlabelled Image" title="Unlabelled Image"〉〈/figure〉〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 5 April 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 212〈/p〉 〈p〉Author(s): Wei-Na Wu, Hao Wu, Run-Bin Zhong, Yuan Wang, Zhi-Hong Xu, Xiao-Lei Zhao, Zhou-Qing Xu, Yun-Chang Fan〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉A novel rhodamine-based Schiff base derivative was obtained via the simple condensation of substituted formyl-1H-pyrrole and rhodamine 6G hydrazone. Fluorescence resonance energy transfer enabled the subsequent use of the derivative as a naked-eye colorimetric and ratiometric fluorescent sensor for Cu〈sup〉2+〈/sup〉 in semi-aqueous solution, and the existence of the morpholine group enabled the further application of the sensor in imaging Cu〈sup〉2+〈/sup〉 in the lysosomes of HeLa cells.〈/p〉〈/div〉 〈/div〉 〈div xml:lang="en"〉 〈h5〉Graphical Abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S1386142518311119-ga1.jpg" width="306" alt="Unlabelled Image" title="Unlabelled Image"〉〈/figure〉〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 5 April 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 212〈/p〉 〈p〉Author(s): Prasenjit Prasad Sukul, Manoj Kumar Mahata, Uttam Kumar Ghorai, Kaushal Kumar〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Through doping of Er〈sup〉3+〈/sup〉/Yb〈sup〉3+〈/sup〉 ions the SrTiO〈sub〉3〈/sub〉 perovskite ceramic is turned into an optically active material keeping its ferroelectric property intact. A huge enhancement of around 20 times in upconversion (UC) emission intensity is observed due to the transformation of cubic crystal structure to tetragonal phase. The intensity ratio of green to red band is found too high to neglect the contribution from the red emission band, which is not observed normally in such type of relatively moderate phonon frequency materials containing Yb〈sup〉3+〈/sup〉/Er〈sup〉3+〈/sup〉 ions. The change in emission intensity is reflected in the decay time measurement. Optical temperature sensing behavior based on FIR technique also has been discussed for Er〈sup〉3+〈/sup〉/Yb〈sup〉3+〈/sup〉 doped SrTiO〈sub〉3〈/sub〉 ceramic.〈/p〉〈/div〉 〈/div〉 〈div xml:lang="en"〉 〈h5〉Graphical Abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S1386142518311090-ga1.jpg" width="301" alt="Unlabelled Image" title="Unlabelled Image"〉〈/figure〉〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 5 April 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 212〈/p〉 〈p〉Author(s): Zhan Zhou, Jiapei Gu, Yuze Chen, Xiaoxia Zhang, Haixia Wu, Xiaoguang Qiao〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉〈em〉Bacillus anthracis〈/em〉 spore causes anthrax to seriously threaten human health and even cause death. 2,6-Pyridinedicarboxylic acid (DPA) is a unique biomarker because it is a major component of 〈em〉Bacillus anthracis〈/em〉 spore. Herein, we design europium functionalized silicon quantum dots as a ratiometric fluorescent nanoprobe to detect DPA with high sensitivity and selectivity. With the addition of DPA, the red emission peaks were observed at 618 nm. The novel probe enables ratiometric and sensitive DPA detection over nanomolar concentrations (as low as 1.02 μM). This work provided an efficient background-free and self-calibrating method for the recognition of DPA.〈/p〉〈/div〉 〈/div〉 〈div xml:lang="en"〉 〈h5〉Graphical Abstract〈/h5〉 〈div〉〈p〉A new ratiometric fluorescent probe based on europium complexes functionalized silicon quantum dots is synthesized and applicated in the detection of DPA with highly selective and sensitive.〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S1386142518311065-ga1.jpg" width="343" alt="Unlabelled Image" title="Unlabelled Image"〉〈/figure〉〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 5 April 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 212〈/p〉 〈p〉Author(s): Smita Verma, Sandip A. Ghuge, V. Ravichandiran, Nihar Ranjan〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉G-quadruplexes are well-known DNA secondary structures which can be formed both within the DNA and the RNA sequences of the human genome. While many functions of G-quadruplex during cell regulatory events are still unknown, a number of reports have established their role in finding new cancer therapies. In this report, we provide a detailed account of Thioflavin T (ThT) interacting with a promoter gene (c-Myc) which has relevance in several types of human cancers. Using a variety of spectroscopic techniques, we have shown that the binding of ThT is selective to c-Myc G-quadruplex only, having poor interactions with the duplex DNA sequences. UV–Visible titration experiments show that binding involves stacking interactions which were further corroborated by CD experiments. Fluorescence studies showed that the binding of ThT to c-Myc G-quadruplex results in a large increase in the fluorescence emission spectrum of c-Myc G-quadruplex while the same to duplex DNAs was much poor. Binding of ThT to c-Myc G-quadruplex results in thermal stabilization of the quadruplex DNA by up to 7.4 °C and Job plot experiments demonstrated the presence of 1:1 and 2:1 ligand to quadruplex complexes. Finally, the docking study suggested that ThT stacks with the guanine bases in one of the grooves which is in agreement with the CD studies. These results are expected to provide leads into the design of new ThT analogs and derivatives for enhancing the stability and selectivity of new G-quadruplex targeting ligands.〈/p〉〈/div〉 〈/div〉 〈div xml:lang="en"〉 〈h5〉Graphical Abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S1386142518311144-ga1.jpg" width="500" alt="Unlabelled Image" title="Unlabelled Image"〉〈/figure〉〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 15 March 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 211〈/p〉 〈p〉Author(s): Yuqi Cao, Jiani Chen, Pingjie Huang, Weiting Ge, Dibo Hou, Guangxin Zhang〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Techniques to inspect and analyze human colorectal cancer cell lines by using terahertz time-domain attenuated total reflection spectroscopy (THz TD-ATR) were investigated. The characteristics of THz absorption spectra of two colorectal cancer cell lines DLD-1 and HT-29 in aqueous solutions with different concentrations were studied. Different spectral features were observed compared to normal cell line. Identification results based on different parameters including absorption coefficient, refractive index, real and imaginary parts of complex permittivity, dielectric loss tangent were discussed. This research may be promising for quick and instant inspection of liquid samples by using THz time-domain spectroscopy in medical applications.〈/p〉〈/div〉 〈/div〉 〈div xml:lang="en"〉 〈h5〉Graphical Abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S1386142518310850-ga1.jpg" width="500" alt="Unlabelled Image" title="Unlabelled Image"〉〈/figure〉〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 15 January 2020〈/p〉 〈p〉〈b〉Source:〈/b〉 Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 225〈/p〉 〈p〉Author(s): Gökhan Dikmen〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Optimized chemical structure, Raman and SERS spectra of 3,5-dimethoxy-4-hydroxycinnamic acid (35D4HCA) molecule and its silver (Ag) complex were calculated using time-dependent density functional theory in conjunction with B3LYP functional and LANL2DZ/6-311 + G(d,p) basis sets. Moreover, excitation and HOMO-LUMO energies were computed by the same level of theory. Because of the fact that energy of excitation electronic transition depends on infinite lifetime approximation, Raman activities were calculated under this approximation. Normal Raman spectra and SERS spectra of 35D4HCA and its silver complex were obtained with different excitation laser frequencies such as 532 nm and 785 nm and so interaction between metal surface and 35D4HCA was examined using SERS spectra. Moreover, theoretical and experimental UV-VIS spectra in the water of 35D4HCA and its silver complex were obtained and transitions, wavelengths and energy values of samples were shown. 〈sup〉1〈/sup〉H NMR experiment of 35D4HCA and its silver complex were performed and it was determined interaction between Ag atoms and 35D4HCA. In order to determine thermal properties of 35D4HCA and its silver complex, TG and DTA analysis were carried out. HOMO and LUMO energy levels corresponding to these energy values were determined and transitions between these levels were determined.〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S1386142519309102-ga1.jpg" width="500" alt="Unlabelled Image" title="Unlabelled Image"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 15 January 2020〈/p〉 〈p〉〈b〉Source:〈/b〉 Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 225〈/p〉 〈p〉Author(s): Archana Singh, Makesh Mohan, Darshak R. Trivedi〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Novel three colorimetric anion receptors R1, R2 and R3 have been designed and synthesized via condensation reaction and characterized using IR, MS, and NMR spectroscopic techniques. Anion sensing properties were studied using colorimetric, UV–vis titration, 〈sup〉1〈/sup〉H NMR titration, and Cyclic Voltammetric Studies. Comparing the UV–visible titration data of the receptors R1 and R2, R2 showed high redshift (∆λ〈sub〉max〈/sub〉) in the mixed competitive solution (DMSO: H〈sub〉2〈/sub〉O, 9: 1; v/v) of about 155 nm, 157 nm, 169 nm for Na〈sup〉+〈/sup〉F〈sup〉−〈/sup〉, Na〈sup〉+〈/sup〉AcO〈sup〉−〈/sup〉, and Na〈sup〉+〈/sup〉AsO〈sub〉2〈/sub〉〈sup〉−〈/sup〉 ions with LOD of 0.23 ppm, 0.18 ppm, and 0.30 ppm, respectively. The observed spectral change of receptor R2 is due to the anion-induced deprotonation of the OH proton, which is confirmed by UV–vis titration, 〈sup〉1〈/sup〉HNMR titration, and cyclic voltammetric studies. Theoretical studies via DFT calculation were carried for R1 and R2 to optimize the structure and to explain the anion-binding mechanism. The application of designed receptor R2 was successfully demonstrated for the detection of F〈sup〉−〈/sup〉 and AsO〈sub〉2〈/sub〉〈sup〉−〈/sup〉 ions using a test strip. The receptors R1 and R2 proved itself to be potentially useful for real-life application by sensing F〈sup〉−〈/sup〉 and AcO〈sup〉−〈/sup〉 ions in real samples like toothpaste, mouthwash, vinegar and seawater in a complete aqueous medium.〈/p〉〈/div〉 〈/div〉 〈div xml:lang="en"〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S1386142519309126-ga1.jpg" width="301" alt="Unlabelled Image" title="Unlabelled Image"〉〈/figure〉〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 15 January 2020〈/p〉 〈p〉〈b〉Source:〈/b〉 Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 225〈/p〉 〈p〉Author(s): Long Liang, Lulu Wei, Guigan Fang, Feng Xu, Yongjun Deng, Kuizhong Shen, Qingwen Tian, Ting Wu, Beiping Zhu〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Wood is the main feedstock source for pulp and paper industry. However, chemical composition variations from multispecies and multisource feedstock heavily affect the production continuity and stability. As a rapid and non-destructive analysis technique, near infrared (NIR) spectroscopy provides an alternative for wood properties on-line analysis and feedstock quality control. Herein, near infrared spectroscopy coupled with partial least squares (PLS) regression was used to predict holocellulose and lignin contents of various wood species including poplars, eucalyptus and acacias. In order to obtain more accurate and robust prediction models, a comparison was conducted among several variable selection methods for NIR spectral variables optimization, including competitive adaptive reweighted sampling (CARS), Monte Carlo-uninformative variable elimination (MC-UVE), successive projections algorithm (SPA), and genetic algorithm (GA). The results indicated that CARS method displayed relatively higher efficiency over other methods in elimination of uninformative variables as well as enhancement of the predictive performance of models. CARS-PLS models showed significantly higher robustness and accuracy for each property using lowest variable numbers in cross validation and external validation, demonstrating its applicability and reliability for prediction of multispecies feedstock properties.〈/p〉〈/div〉 〈/div〉 〈div xml:lang="en"〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S1386142519309059-ga1.jpg" width="288" alt="Unlabelled Image" title="Unlabelled Image"〉〈/figure〉〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 15 January 2020〈/p〉 〈p〉〈b〉Source:〈/b〉 Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 225〈/p〉 〈p〉Author(s): Susmita Chowdhury, Sutanwi Bhuiya, Lucy Haque, Suman Das〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The use of bioactive flavonoids as drugs has long mesmerized the scientific world. Their small size and planar structure enables them to interact with limitless substrates especially biomolecules. Taxifolin is a flavonoid well known for its anti-oxidizing and metal chelating properties. Its interaction with a few biomolecules has been studied so far to exploit its pharmacological activities. Hemoglobin, an iron containing macromolecule acts as a major carrier protein and is also associated with the occurrence of many diseases. Our present study lays emphasis on the interaction of flavanonol taxifolin with bovine hemoglobin at physiological pH. This was achieved by monitoring the changes in the absorbance, fluorescence, anisotropic, lifetime and circular dichroic spectra. Benesi-Hildebrand plot determined a binding constant value of 20.0 × 10〈sup〉3〈/sup〉 M〈sup〉−1〈/sup〉 at 25 °C. Stern-Volmer quenching studies reveal that the binding is associated with a static mode of quenching. The complexation is thermodynamically favored as indicated by the negative value of enthalpy and positive value of entropy changes seen from the van't Hoff plot. Theoretical DFT calculations were used to find out an optimized geometry and HOMO-LUMO energy gap for taxifolin. Molecular docking studies revealed the location of taxifolin inside the hemoglobin moiety.〈/p〉〈/div〉 〈/div〉 〈div xml:lang="en"〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S1386142519309035-ga1.jpg" width="326" alt="Unlabelled Image" title="Unlabelled Image"〉〈/figure〉〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 15 January 2020〈/p〉 〈p〉〈b〉Source:〈/b〉 Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 225〈/p〉 〈p〉Author(s): Madhumitha Chinnasamy, Karthikeyan Balasubramanian〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The influence of Cu-doping on their structural, vibrational and morphological properties of hydrothermally prepared Cu-doped WO〈sub〉3〈/sub〉 has been studied. X-ray Diffraction studies confirm the tetragonal structure of WO〈sub〉3〈/sub〉 and lower angle shift in doped samples indicates the incorporation of Cu in tungsten sites. Field emission scanning electron microscopy (FESEM) images exhibit micro rod-like morphology of the as-synthesized WO〈sub〉3〈/sub〉 materials shows microstructure with rod-like projections slowly changes into nanorods and plates for doped samples. The absorption peak of pure and Cu-doped WO〈sub〉3〈/sub〉 occurs in the region of 200 to 350 nm and centered at 314 nm. In Raman spectra, prominent peaks of WO〈sub〉3〈/sub〉 have appeared at 676 and 810 cm〈sup〉−1〈/sup〉 which represent the stretching mode of υ〈sub〉a〈/sub〉 (O〈img src="https://sdfestaticassets-eu-west-1.sciencedirectassets.com/shared-assets/16/entities/sbnd"〉W〈img src="https://sdfestaticassets-eu-west-1.sciencedirectassets.com/shared-assets/16/entities/sbnd"〉O). Peak around 240 cm〈sup〉−1〈/sup〉 represents the bending vibration of υ (W〈img src="https://sdfestaticassets-eu-west-1.sciencedirectassets.com/shared-assets/16/entities/sbnd"〉O〈img src="https://sdfestaticassets-eu-west-1.sciencedirectassets.com/shared-assets/16/entities/sbnd"〉W). Another peak at 322 cm〈sup〉−1〈/sup〉 is the deformation mode δ (O〈img src="https://sdfestaticassets-eu-west-1.sciencedirectassets.com/shared-assets/16/entities/sbnd"〉W〈img src="https://sdfestaticassets-eu-west-1.sciencedirectassets.com/shared-assets/16/entities/sbnd"〉O). Force constant of the prepared samples has been calculated from the blue shift obtained in both stretching and bending vibrational mode by varying laser power from 0.045 to 11.25 mW. Phonon lifetime has been calculated by deconvoluting the peaks using Lorentzian function.〈/p〉〈/div〉 〈/div〉 〈div xml:lang="en"〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S1386142519309047-ga1.jpg" width="433" alt="Unlabelled Image" title="Unlabelled Image"〉〈/figure〉〈/p〉〈/div〉 〈/div〉