ALBERT

Description: Ischemia/reperfusion cerebral injury can cause serious damage to nerve cells. The injured organelles are cleared by autophagy eventually, which is critical for cell survival. Dexmedetomidine is neuroprotective in various ischemia/reperfusion models. Mitochondrial calcium uniporter (MCU) is the most important channel of mitochondrial Ca2+ influx into mitochondria, where Ca2+ has a potential effect on mitochondrial autophagy. However, the role of MCU in the changes of mitophagy and autophagy caused by dexmedetomidine is unknown. In this study, we constructed an in vitro I/R model by subjecting the oxygen and glucose deprivation/reperfusion model to SH-SY5Y cells to mimic the cerebral I/R injury. We found that postconditioning with dexmedetomidine and 3-methyladenine (3MA, an autophagy inhibitor) increased the cell survival meanwhile reduced the production of autophagic vesicles and the expression of LC3 and Beclin 1. This process also increased the expression of BCL-2, P62, and TOM20. After applied with spermine (MCU-specific agonist), the expression of autophagy proteins by dexmedetomidine was reversed, and the same changes were also observed in immunofluorescence. The results of our study suggested that dexmedetomidine can inhibit MCU and reduce excessive mitophagy and autophagy for conferring protection against I/R injury.

Description: To implement EU REACH- (Registration, Evaluation, and Authorization of Chemicals-) like chemical legislations in various countries of which the purpose is human and environment safety, the first step is substance identification followed by the hazard and risk assessments. Although both structural and composition identifications are required, the latter can more importantly result in the essential data to fill out the required substance information such as purity and concentrations of constituents, as well as impurities. With fatty acid zinc salts (FAZSs) as an exemplary industrial chemical of which chromatographic and nuclear magnetic resonance (NMR) analyses were impossible due to their insolubility in water and any organic solvents, the composition characterization was tried by preparing their fatty acid methyl esters (FAMEs) using the conc. HCl/methanol/toluene method. This acid-catalyzed methyl esterification was optimized with zinc stearate as a surrogate substance. Gas chromatography-mass spectrometry (GC-MS) and NMR analyses on methyl-esterified products revealed that the optimum conditions were at 90°C for 10 min or 45°C for 30 min with two equivalent HCl as well as at 45°C for 10 min with five equivalent HCl. Almost all zinc stearates were converted into the corresponding fatty acids with 97–99% conversion rates. Free fatty acids (FFAs) were detected in extracted ion chromatograms of pyrolysis-gas chromatography-mass spectrometry (Py-GC-MS) in the methyl-esterified products with incomplete conversions of 73∼79%. The optimized conc. HCl/methanol/toluene method of direct one-step reaction from FAZSs was compared with the two-step NaOH saponification/BF3-methanol method after acidic hydrolysis of FAZSs. The mechanism of fatty acid zinc salts into free fatty acids and fatty acid methyl esters was suggested with the evidence of the formation of Zn(OH)2.

Description: In order to improve the strength and resistance of ordinary nonel tubes, calcium sulfate whiskers (CSW, treated with silane coupling agent) and maleic anhydride grafted polyethylene (PE-g-MAH) are used to control the wall material of the nonel tube that the blending of the low-density polyethylene was enhanced. The effects of mass fraction of CSW or PE-g-MAH on the tensile properties, interfacial structure, melting and crystallization characteristics, and thermal decomposition behavior of the composite system were studied, and the thermal decomposition kinetics were calculated. The results show that, relative to pure LDPE, the strength of LDPE/CSW (85/15) is increased by 7.58%, and the strength of LDPE/CSW/PE-g-MAH (84/15/1) is increased by 7.58%. The addition of CSW or PE-g-MAH has gradually changed the fracture mode of the LDPE matrix. Thermal analysis shows that CSW can reduce the crystallinity of LDPE. The melting and crystallization characteristics of LDPE/CSW/PE-g-MAH composites have little effect, but the thermal decomposition stability is improved. The kinetic analysis showed that the reaction order (n) was around 1, CSW could improve LDPE/CSW thermal decomposition activation energy, and PE-g-MAH increased the thermal decomposition activation energy of LDPE/CSW/PE-g-MAH.

Description: Chloramphenicol- (CAP-) restricted access media-molecularly imprinted polymers (CAP-RAM-MIPs) were prepared by precipitation polymerization using CAP as a template molecule, 2-diethylaminoethyl methacrylate (DEAEM) as a functional monomer, ethylene glycol dimethyl acrylate (EDMA) as a crosslinking agent, glycidyl methacrylate (GMA) as an outer hydrophilic functional monomer, and acetonitrile as a pore former and solvent. The CAP-RAM-MIPs were successfully characterized by Fourier-transform infrared spectroscopy, scanning electron microscopy, and thermogravimetric analysis. The adsorption performance was investigated in detail using static, dynamic, and selective adsorption experiments. Adsorption equilibrium could be reached within 11 min. The CAP-RAM-MIPs had a high adsorption rate and good specific adsorption properties. Scatchard fitting curves indicated there were two binding sites for CAP-RAM-MIPs. Adsorption was Freundlich multilayer adsorption and consistent with the quasi-second kinetic model. Using CAP-RAM-MIPs for selective separation and enrichment CAP in bovine serum in combination with high-performance liquid chromatography (HPLC), CAP recovery ranged from 94.1 to 97.9% with relative standard deviations of 0.7–1.5%. This material has broad application prospects in enrichment and separation.

Description: Anlotinib is a novel inhibitor of receptor kinase tyrosine with multitargets and has a broad spectrum of inhibitory action on tumor angiogenesis and growth. A simple and rapid UHPLC-MS/MS bioanalytical method was validated for the determination of anlotinib in rat plasma, using imatinib as an internal standard. An Acquity BEH C18 column was used to separate analytes. The eluents consisted of formic acid/water (0.1 : 100, v/v) and acetonitrile with a mobile phase. A triple quadrupole mass spectrometer was operated for the quantification with multiple reaction monitoring (MRM) to determine transitions: 408.2 ⟶ 339.1 for anlotinib, and 494.3 ⟶ 394.1 for imatinib. The validated range was 0.1–50 ng/mL for anlotinib. Mean recovery rate of anlotinib in plasma was ≥99.32% and reproducible. Also, the intra- and interday precisions were both below 15%. This robust method was successfully applied to support the pharmacokinetic study of anlotinib in rats.

Description: The purpose of this study was to develop and validate a discriminative dissolution method for the metformin film-coated tablet with immediate release of the active substance that belongs to class III of the Biopharmaceutical Classification System (BCS). Different conditions such as type of dissolution medium, volume of dissolution medium, rotation speed, apparatus, and filter suitability were evaluated. The most discriminative release profile for the metformin film-coated tablet was accomplished by using Apparatus II (paddle) and 1000 mL of phosphate buffer pH 6.8 as the dissolution medium and maintained on 37 ± 0.5°C with a rotation speed of 75 rpm. The quantification of the released active substance was performed by UV/Vis spectrophotometry, at 232 nm. Acceptance criteria for not less than 75% (Q) of the labeled content for 45 minutes were set. The dissolution method was validated according to the current international guidelines using the following parameters: specificity, accuracy, precision, linearity, robustness, and stability of the solutions, found to be meeting the predetermined acceptance criteria. A developed dissolution method has discriminatory power to reflect the characteristics of the medicinal product and is able to distinguish any changes related to quantitative formulation and can be also applied for routine batch testing.

Description: Exposure to fluoride beyond the recommended level for longer duration causes both dental and skeletal fluorosis. Thus, the development of cost-effective, locally available, and environmentally benign adsorbents for fluoride removal from contaminated water sources is absolutely required. In the present study, diatomaceous earth (diatomite) locally available in Ethiopia, modified by treating it with an aluminum hydroxide solution, was used as an adsorbent for fluoride removal from aqueous solutions. Adsorption experiments were carried out by using batch contact method. The adsorbent was characterized using FT-IR spectroscopy. Effects of different parameters affecting efficiency of fluoride removal such as adsorbent dose, contact time, initial fluoride concentration, and pH were investigated and optimized. The optimum adsorbent dose, contact time, initial fluoride concentration, and pH values were 25 g/L, 180 min, 10 mg/L, and 6.7, respectively. The performance of the adsorbent was also tested under optimum conditions using groundwater samples taken from Hawassa and Ziway. Langmuir and Freundlich isotherm models were applied to describe the equilibrium data. Compared to Langmuir isotherm (R2 = 0.888), the Freundlich isotherm (R2 = 0.985) model was better fitted to describe the adsorption characteristics of fluoride on Al-diatomite. The Langmuir maximum adsorption capacity was 1.67 mg/g. The pseudosecond-order model was found to be more suitable than the pseudofirst-order to describe the adsorption kinetics. The low correlation coefficient value of R2 = 0.596 for the intraparticle diffusion model indicates that the intraparticle diffusion model does not apply to the present studied adsorption system. The maximum fluoride removal was observed to be 89.4% under the optimum conditions which indicated that aluminum hydroxide-modified diatomite can be used as efficient, cheap, and ecofriendly adsorbents for the removal of fluoride from contaminated water.

Description: Ginkgo leaves were used as precursors for the hydrothermal synthesis of carbon quantum dots (CQDs), which were subsequently characterized by transmission electron microscopy as well as Fourier-transform infrared, X-ray powder diffraction, and X-ray photoelectron spectroscopy. The prepared CQDs exhibited a fluorescence quantum yield of 11% and superior water solubility and fluorescence stability, as well as low cytotoxicities and excellent biocompatibilities with A549 and HeLa cells; these CQDs were also used to bioimage HeLa cells. Moreover, owing to the experimental observation that Hg2+ quenches the fluorescence of the CQDs in a specific and sensitive manner, we developed a method for the detection of Hg2+ using this fluorescence sensor. The sensor exhibited a linear range for Hg2+ of 0.50–20 μM, with an excellent coefficient of determination (R2 = 0.9966) and limit of detection (12.4 nM). In practice, the proposed method was shown to be highly selective and sensitive for the monitoring of Hg2+ in lake water and serum samples.

Description: Parkinson’s disease (PD) is a progressive health issue and influences an increasingly larger number of people, especially at older ages, affecting the central nervous system (CNS). Alpha-synuclein is a biomarker closely correlated with the CNS and PD. The loss of neuronal cells in the substantia nigra leads to the aggregation of alpha-synuclein in the form of Lewy bodies, and Lewy neuritis is a neuropathological hallmark. The therapeutic approach of PD focuses on alpha-synuclein as an important substrate of PD pathology. So far, research has focused on antialpha-synuclein to minimize the burden of extracellular alpha-synuclein in the brain, and as a consequence, it ameliorates inflammation. Interdigitated electrode (IDE) biosensors are efficient tools for detecting various analytes and were chosen in this study to detect alpha-synuclein on amine-modified surfaces by using antiaptamer-alpha-synuclein as the probe. In addition, a gold nanoparticle-conjugated aptamer was used to enhance the detection limit. The limit of detection for the binding between alpha-synuclein and aptamer was found to be 10 pM. Control experiments were performed with two closely related proteins, amyloid-beta and tau, to reveal the specificity; the results show that the aptamer only recognized alpha-synuclein. The proposed strategy helps to identify the binding of aptamer and alpha-synuclein and provides a possible method to lower alpha-synuclein levels and inflammation in PD patients.

Description: The simultaneous determination of betamethasone, dexchlorpheniramine maleate, and sodium benzoate in pharmaceutical syrup was done by using a simple validated HPLC method. The chromatographic separation of the three analytes was done in a C18 column maintained at 25°C, using a mixture of acetonitrile and 0.02 M phosphate buffer solution pH 2.70 (35 : 65, v : v) as mobile phase. The isocratic elution was chosen with total flow rate of mobile phase maintained at 1.0 mL per minute. The analytes were detected by a UV-Vis detector set at 254 nm. Injection volume was set at 50 μl. The method was fully validated in terms of specificity, linearity, precision, accuracy, and robustness according to requirements of current guidelines and was proven to be suitable for the intended application.