ALBERT

Description: 〈p〉Publication date: 1 November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Materials Letters, Volume 254〈/p〉 〈p〉Author(s): Mohamad Fahrul Radzi Hanifah, Juhana Jaafar, M.H.D. Othman, A.F. Ismail, M.A. Rahman, Norhaniza Yusof, Farhana Aziz〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Nanocluster-like Pt nanoparticles/reduced graphene oxide nanocomposite catalyst (NC-PtNPs/RGO) was synthesized through a novel one-step process of chemical reduction-assisted hydrothermal reaction by using formic acid as reducing agent. The crystallinity, morphology and composition of the NC-PtNPs/RGO catalysts were extensively characterized. The as-prepared NC-PtNPs/RGO catalysts exhibited higher electro-catalytic activity towards methanol oxidation than carbon black (CB)/PtNPs catalyst and could be ascribed to the high dispersion of NC-Pt NPs with large electrochemical surface area, release more exposure of active sites by NC-PtNPs structure and synergy effect of RGO.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 15 October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Materials Letters, Volume 253〈/p〉 〈p〉Author(s): Zhenhua Wang, Yi Liu〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Σ3 boundaries improve the intergranular corrosion resistance of high nitrogen austenitic stainless steels. However, the regeneration of these boundaries is, unfortunately, accompanied by significant grain coarsening. 18Mn18Cr0.5N and 18Mn18Cr0.6N steels were thermo-mechanically processed and the corresponding microstructures were evaluated. Formation mechanisms were proposed for Σ1 boundaries in different R-Σ3-Σ1-type junctions. These boundaries formed during grain growth accompanying Σ3 formation and reaction. After 30% cold tension and cyclic heating between 500 °C and 1100 °C, numerous Σ1 boundaries were formed and disrupted the high angle grain boundary network efficiently. Moreover, a small grain size was maintained. Σ1 boundaries have significant application potential in grain boundary engineering.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 1 November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Materials Letters, Volume 254〈/p〉 〈p〉Author(s): Rui Wang, Dongdong Gu, Lixia Xi, Kaijie Lin, Meng Guo, Hongmei Zhang〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Selective laser melting (SLM), as a rapidly developed layer-by-layer 3D printing technology, has been demonstrated that it can be used for additive manufacturing of multi-materials. In this work, TiB〈sub〉2〈/sub〉/Ti6Al4V multi-materials were manufactured by SLM. The results showed that interfacial microstructures consisting of un-melted TiB〈sub〉2〈/sub〉 powders, columnar TiB crystals, and acicular TiB crystals were formed in the molten pool. Meanwhile, a variation nanohardness was developed with chemical compositions at the interfacial regions, owing to an in-situ reaction of Ti and TiB〈sub〉2〈/sub〉. The first-principle calculations were used to reveal the axial growth of TiB crystals as well as the different hardness of this system.〈/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-S0167577X19310006-ga1.jpg" width="346" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 15 October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Materials Letters, Volume 253〈/p〉 〈p〉Author(s): Siyao Xie, Ruidi Li, Linjun Tang, Tiechui Yuan〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The diffusion behavior of Al in FeCoCrNiMo〈sub〉x〈/sub〉 high-entropy alloys (HEAs) at temperatures ranging from 773 to 873 K with and without pulse current was studied in this paper. The diffusion coefficients 〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" altimg="si2.svg"〉〈mi〉D〈/mi〉〈/math〉 was determined based on the Fick’s law and corresponding pre-exponential factor 〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" altimg="si3.svg"〉〈msub〉〈mi〉D〈/mi〉〈mn〉0〈/mn〉〈/msub〉〈/math〉, as well as activation energy 〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" altimg="si4.svg"〉〈msub〉〈mi〉Q〈/mi〉〈mi〉D〈/mi〉〈/msub〉〈/math〉. It was found that the 〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" altimg="si2.svg"〉〈mi〉D〈/mi〉〈/math〉 under pulse current dramatically increased about hundreds of times in contrast with that without current. In addition, the 〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" altimg="si3.svg"〉〈msub〉〈mi〉D〈/mi〉〈mn〉0〈/mn〉〈/msub〉〈/math〉 and 〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" altimg="si4.svg"〉〈msub〉〈mi〉Q〈/mi〉〈mi〉D〈/mi〉〈/msub〉〈/math〉 were determined to reduce from 〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" altimg="si5.svg"〉〈mrow〉〈msubsup〉〈mrow〉〈mn〉1.369〈/mn〉〈/mrow〉〈mrow〉〈mo〉-〈/mo〉〈mn〉0.324〈/mn〉〈/mrow〉〈mrow〉〈mo〉+〈/mo〉〈mn〉0.424〈/mn〉〈/mrow〉〈/msubsup〉〈mo〉×〈/mo〉〈msup〉〈mrow〉〈mn〉10〈/mn〉〈/mrow〉〈mrow〉〈mo〉-〈/mo〉〈mn〉13〈/mn〉〈/mrow〉〈/msup〉〈/mrow〉〈/math〉 to 〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" altimg="si17.svg"〉〈mrow〉〈msubsup〉〈mrow〉〈mn〉5.016〈/mn〉〈/mrow〉〈mrow〉〈mo〉-〈/mo〉〈mn〉1.984〈/mn〉〈/mrow〉〈mrow〉〈mo〉+〈/mo〉〈mn〉3.284〈/mn〉〈/mrow〉〈/msubsup〉〈mo〉×〈/mo〉〈msup〉〈mrow〉〈mn〉10〈/mn〉〈/mrow〉〈mrow〉〈mo〉-〈/mo〉〈mn〉15〈/mn〉〈/mrow〉〈/msup〉〈/mrow〉〈/math〉 m〈sup〉2〈/sup〉/s, and from 〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" altimg="si6.svg"〉〈mrow〉〈mn〉39.7〈/mn〉〈mo〉±〈/mo〉〈mn〉1.8〈/mn〉〈/mrow〉〈/math〉 to 〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" altimg="si18.svg"〉〈mrow〉〈mn〉21.6〈/mn〉〈mo〉±〈/mo〉〈mn〉3.4〈/mn〉〈/mrow〉〈/math〉 kJ/mol respectively with the Mo contents increasing from Mo〈sub〉0〈/sub〉 to Mo〈sub〉0.2〈/sub〉 without pulse current. The introduction of pulse current into the diffusion couples dramatically promoted the 〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" altimg="si3.svg"〉〈msub〉〈mi〉D〈/mi〉〈mn〉0〈/mn〉〈/msub〉〈/math〉 at all the diffusion couples. However, the pulse current was ascertained to obviously increase the 〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" altimg="si4.svg"〉〈msub〉〈mi〉Q〈/mi〉〈mi〉D〈/mi〉〈/msub〉〈/math〉 in contrast to that of diffusion couples without pulse current.〈/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-S0167577X19309899-ga1.jpg" width="271" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 5 October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Alloys and Compounds, Volume 804〈/p〉 〈p〉Author(s): Yuliang Jiang, Xueyan Fu, Zidong Zhang, Wei Du, Peitao Xie, Chuanbing Cheng, Runhua Fan〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Carbon nanofibers embedded with magnetic Fe〈sub〉3〈/sub〉C nanoparticles have been synthesized using electrospinning technique, followed by one-step carbonization. By using Fe〈sub〉3〈/sub〉C/C nanofibers as filler with 10% content, the sample can achieve a minimum reflection loss (RL) of −54.94 dB with a thickness of 1.36 mm, as well as the broad effective absorption bandwidth (EAB) can reach to 4.5 GHz (13.3–17.8 GHz) at the thickness of 1.55 mm. The superior properties might be due to the synergistic effects of dielectric loss, magnetic loss, multiple scattering and reflection. This work presents a facile and promising method to produce high performance microwave absorption materials with thin thickness, light weight and strong absorption.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 5 October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Alloys and Compounds, Volume 804〈/p〉 〈p〉Author(s): E.J. Pickering, K.A. Christofidou, H.J. Stone, N.G. Jones〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉In order to reduce the environmental impact of air travel, it is desirable that the efficiencies of gas turbine engines are increased. One way to achieve this goal is to increase the operating temperatures of the engine cores. Unfortunately for aero-engine manufacturers, the temperature capability limits of the Ni-base superalloys used currently have been reached. Hence, new alloys need to be developed that are capable of operating at significantly higher temperatures. In this article, the potential of tantalum-base superalloys is discussed and explored. A suite of alloys based on the Ta-Al-Co system was investigated. It was found that an array of fine carbide precipitates was formed in the Ta-rich matrix in a subset of the alloys, which is promising in terms of developing a strong and damage-tolerant microstructure, but that the elemental partitioning of Al out of the matrix accompanying precipitation is likely to degrade environmental resistance. Nevertheless, it is believed that the design principles described have the potential to facilitate the development of the next generation of high-temperature alloys based on systems of this type.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 5 October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Alloys and Compounds, Volume 804〈/p〉 〈p〉Author(s): C.Q. Zhou, Q.A. Zhang〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉In order to understand the effect of Pr〈sub〉3〈/sub〉Al〈sub〉11〈/sub〉 nanoparticles on crystallite growth kinetics of nanocrystalline Mg, the crystallite growth characteristics in a Mg−Pr〈sub〉3〈/sub〉Al〈sub〉11〈/sub〉 composite and a pure Mg sample were comparatively investigated in this work. The crystallite growth exponents of nanocrystalline Mg in the Mg−Pr〈sub〉3〈/sub〉Al〈sub〉11〈/sub〉 composite and pure Mg were determined as 〈em〉n〈/em〉 = 5 and 〈em〉n〈/em〉 = 4, respectively. Meanwhile, the activation energy for crystallite growth in Mg−Pr〈sub〉3〈/sub〉Al〈sub〉11〈/sub〉 composite was calculated to be 118.8 kJ/mol, which is higher than 97.1 kJ/mol in pure nanocrystalline Mg. Further studies reveal that the rise of crystallite growth exponent and increase of activation energy in the Mg−Pr〈sub〉3〈/sub〉Al〈sub〉11〈/sub〉 composite are primarily attributed to the pinning effect of Pr〈sub〉3〈/sub〉Al〈sub〉11〈/sub〉 nanoparticles at crystallite boundaries of Mg.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 5 October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Alloys and Compounds, Volume 804〈/p〉 〈p〉Author(s): Liming Tan, Yunping Li, Wenkai Deng, Yong Liu, Feng Liu, Yan Nie, Liang Jiang〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Three Ni-base powder metallurgy superalloys have been developed recently, and tensile tests at temperatures ranging from room temperature (RT) to 815 °C were conducted on them. The results conformed their excellent tensile properties, in comparison with several other existed polycrystalline superalloys. In this work, by means of microstructure characterization, thermal dynamic calculations, and theoretical modeling, different strengthening mechanisms including precipitation strengthening, grain boundary strengthening, solid solution strengthening, and Orowan strengthening, were found to contribute to the yield strength in different degrees, which would help to further enhance the tensile properties of these alloys through composition design and processing optimization thereafter.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0925838819324892-fx1.jpg" width="459" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 1 September 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Acta Materialia, Volume 176〈/p〉 〈p〉Author(s): Denise C. Ford, David Hicks, Corey Oses, Cormac Toher, Stefano Curtarolo〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Metallic glasses are excellent candidates for biomedical implant applications due to their inherent strength and corrosion resistance. However, use of metallic glasses in structural applications is limited because bulk dimensions are challenging to achieve. Glass-forming ability (GFA) varies strongly with alloy composition and becomes more difficult to predict as the number of chemical species in a system increases. Here, we present a theoretical model — implemented in the AFLOW framework — for predicting GFA based on the competition between crystalline phases. The model is applied to biologically relevant binary and ternary systems. Elastic properties of Ca- and Mg-based systems are estimated for use in biodegradable orthopedic support applications. Alloys based on Ag〈sub〉0.33〈/sub〉Mg〈sub〉0.67〈/sub〉, Cu〈sub〉0.5〈/sub〉Mg〈sub〉0.5〈/sub〉, Cu〈sub〉0.37〈/sub〉Mg〈sub〉0.63〈/sub〉, and Cu〈sub〉0.25〈/sub〉Mg〈sub〉0.5〈/sub〉Zn〈sub〉0.25〈/sub〉, and in the Ag-Ca-Mg and Ag-Mg-Zn systems, are recommended for further study.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S1359645419304380-fx1.jpg" width="500" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/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: 1 November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Materials Letters, Volume 254〈/p〉 〈p〉Author(s): C.Q. Zhang, W. Liu〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The Al〈sub〉3〈/sub〉Ti intermetallic compound (IMC) layer growth kinetics at Al-Ti interface was investigated. Surprisingly an abnormal effect of temperature was observed with a thicker IMC layer formed at lower annealing temperature due to the much faster Al〈sub〉3〈/sub〉Ti grain coarsening at a higher temperature, the IMC layer growth at 630 °C became slower than that at 600 °C after a certain annealing time. The quantitative influence of grain size on effective diffusion coefficient was analysed. Calculations showed that the lattice diffusion makes little contribution to the effective diffusion coefficient. Grain boundary diffusion, therefore, dominates for all the annealing conditions studied.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: July–August 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Materials Today, Volume 27〈/p〉 〈p〉Author(s): David Bradley〈/p〉

Description: 〈p〉Publication date: October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Scripta Materialia, Volume 171〈/p〉 〈p〉Author(s): Guang Wang, Xiannian Sun, Jinhai Xu, Yingchun Shan, Xiaoguang Han, Jiujun Xu, Jiangtao Li〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Two transparent AlON ceramics substrates were successfully pressureless joined at 1880 °C for 80 min by using a powder interlayer of parent material. The grains on the interface of the joint were simultaneously shared by both interlayer and substrates due to grain growth and coalescence, which can evidently be categorized as thermal diffusion bonding under pressureless condition. The identical phase assemblage and microstructure for both interlayer and substrates lead to a bending strength of the joint (229.1 MPa) nearly equal to that of substrates, which is much higher than that of the reported AlON joints.〈/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-S1359646219303835-ga1.jpg" width="242" alt="Unlabelled Image" title="Unlabelled Image"〉〈/figure〉〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 1 August 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Tetrahedron Letters, Volume 60, Issue 31〈/p〉 〈p〉Author(s): Tao-Shan Jiang, Yuhui Zhou, Long Dai, Xiaojun Liu, Xiuli Zhang〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉A metal-free 〈em〉p〈/em〉-toluenesulfonic acid (TsOH·H〈sub〉2〈/sub〉O) mediated synthesis of 3-ketoquinolines from anilines, enaminones and DMSO has been developed. In this transformation, DMSO was activated by TsOH·H〈sub〉2〈/sub〉O and provided the one-carbon unit of the 3-ketoquinolines. A plausible mechanism involving an electrophilic sulfenium ion intermediate was proposed.〈/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-S0040403919306562-ga1.jpg" width="500" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 1 August 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Tetrahedron Letters, Volume 60, Issue 31〈/p〉 〈p〉Author(s): Lifeng Wang, Qingshan Tian, Chen Bin, Guozhu Zhang〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉A novel copper-catalyzed amination of ethers using isocyanates and DTBP is developed. The reaction provides a unique approach to the synthesis of Boc-protected α-aminals through three-component radical cascade reactions. It provides an alternative method for the construction of this type of valuable motifs in high yield. Meanwhile, the method exhibits high tolerance of various functional groups, such as ether, halide, ester and acyl functionalities.〈/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-S0040403919306598-ga1.jpg" width="500" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: Available online 6 July 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Tetrahedron Letters〈/p〉 〈p〉Author(s): Hironori Okamura, Takanobu Fujioka, Naoki Mori, Tohru Taniguchi, Kenji Monde, Hidenori Watanabe, Hirosato Takikawa〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Salinipostins are cyclic enol-phosphotriesters isolated from a marine-derived 〈em〉Salinispora〈/em〉 sp. as antimalarial compounds. Herein, the first enantioselective synthesis of salinipostin A was achieved. Organocatalyst-mediated asymmetric cyclopropanation and regioselective cyclopropane ring opening were the key 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-S0040403919306549-ga1.jpg" width="500" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Petroleum Science and Engineering, Volume 181〈/p〉 〈p〉Author(s): Jingyi Zhu, Zhaozhong Yang, Xiaogang Li, Zhichao Song, Ziwei Liu, Shiyi Xie〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Liquid foam is an alternative to water-based fracturing fluid due to its great proppant suspension ability. In this work, theoretical and experimental investigations on the settling behavior of the proppants in viscoelastic foams were analyzed on bubble scale. Settling trajectory was captured over time by optical microscope to calculate proppant settling velocity. At room temperature, proppants kept suspended well, but noticeable changes in proppant position could be observed at 70 °C. We concluded that the sedimentation of the proppants at high temperature was divided into three stages, that were drainage-dominated, structure-dominated and fluid-dominated regimes. For the large proppants, quick settling velocity was seen at first due to fast drainage rate. Then bubble pressure force and network force served as drag force exerting on the proppants when the proppants stretched or squeezed the liquid films. During this regime, bubble distribution, the existence of nodes, the length and the orientation of Plateau border leaded to the fluctuation in settling velocity. Lastly, the proppants would also flow freely along Plateau border over time, and the properties of the foam fluid such as viscosity and elasticity provided the drag force to prevent the proppants from settling. It's more likely for small proppants to change to this stage called fluid-dominated regime, but elasticity also guaranteed their low settling velocity. Moreover, in the existence of proppants, the analysis into drainage rate and bubble structure demonstrated the high stability of viscoelastic foams. These results helped understand the sedimentation of proppants in wet foams and broadened the application of viscoelastic foams in hydraulic fracturing.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: Available online 6 July 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Tetrahedron Letters〈/p〉 〈p〉Author(s): Soumen Biswas, Anubha Yadav, Debashis Majee, Shaikh M. Mobin, Sampak Samanta〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉A simple, efficient, one-pot sequential process for the preparation of a family of 8,9-dihydropyrido[1,2–〈em〉a〈/em〉]indol-6(7H)-one scaffolds in acceptable yields has been established under mild conditions. The Michael-hemiaminalization-oxidation reaction proceeds between methyl 2-(3-formyl-1〈em〉H〈/em〉-indol-2-yl) acetate and 〈em〉trans〈/em〉-β-aryl/alkyl-substituted acroleins using pyrrolidine-BzOH as an efficient organocatalyst, followed by oxidation of in situ generated of C,〈em〉N〈/em〉-fused hemiaminal adducts in the presence of PDC at room temperature. Excitingly, organobase-catalyzed highly diastereoselective (up to ≤9:1 dr) construction of a series of pharmacologically attractive 1,2,3-fused tetracyclic indole scaffolds with five contiguous chiral centers including an all-carbon stereogenic center has been realized through our developed method. Moreover, pyrrolidine-BzOH and PTSA as combined catalytic systems promote the uninterrupted sequential Michael-cyclization reaction, followed by 〈em〉N〈/em〉-alkylation reaction with carbazole to produce interesting class of 6-(9〈em〉H〈/em〉-carbazol-9-yl)-6,7,8,9-tetrahydropyrido[1,2–〈em〉a〈/em〉]indole derivatives in a diastereoselective manner.〈/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-S0040403919306574-ga1.jpg" width="500" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Petroleum Science and Engineering, Volume 181〈/p〉 〈p〉Author(s): Zhong-Zhen Chen, Hong-Ze Gang, Jin-Feng Liu, Bo-Zhong Mu, Shi-Zhong Yang〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉A thermal-stable and salt-tolerant biobased zwitterionic surfactant 〈em〉N, N〈/em〉-Dimethyl-〈em〉N〈/em〉-[2-hydroxy-3-sulfo-propyl]-〈em〉N〈/em〉′-phenyloctadecanoyl-1, 3-diaminopropane (SPODP) was successfully obtained from modification of oleic acids which can be regenerated from waste cooking oils, and its structure was characterized using GC-MS, ESI-MS and 〈sup〉1〈/sup〉H NMR approaches. The biobased zwitterionic surfactant demonstrated a strong interfacial activity at high salinity and high temperature conditions at a very low surfactant dosage in formation brine. The ultralow interfacial tension (≤10〈sup〉−3〈/sup〉 mN/m) between crude oil and brine was reached at 0.5 g/L in brine with a wide range compatibility of NaCl up to saturation, Ca〈sup〉2+〈/sup〉 up to 500 mg/L, and temperature up to 95 °C. Meanwhile, it also exhibited strong wetting ability and resistance against adsorption on sands. All the results from this study suggest that the biobased zwitterionic surfactant is promising over varieties of traditional surfactants in applications in alkali free systems in enhanced oil recovery (EOR).〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Carbon, Volume 153〈/p〉 〈p〉Author(s): A-Young Kim, Ryanda Enggar Anugrah Ardhi, Guicheng Liu, Ji Young Kim, Hyun-Jin Shin, Dongjin Byun, Joong Kee Lee〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉A hierarchical hollow SnO/SnO〈sub〉2〈/sub〉 heterostructure anode surrounded by a dual carbon layer (DCL@SnO/SnO〈sub〉2〈/sub〉), inner (host) and outer carbon layers, was successfully designed 〈em〉via〈/em〉 a simple hydrothermal method with a single Sn precursor to achieving high-performance Li-ion batteries (LIBs) and Li-ion capacitors (LICs). The carbon nanotube (CNT)-based inner carbon host and an ultrathin outer amorphous carbon layer introduced at the SnO/SnO〈sub〉2〈/sub〉 heterostructure had good elasticity and high electrical properties to prevent volume change and ensure fast Li-ion transport during cycling, respectively. Meanwhile, the SnO/SnO〈sub〉2〈/sub〉 heterostructure comprising p-type SnO and n-type SnO〈sub〉2〈/sub〉 facilitated further fast interfacial Li-ion transfer within the p–n SnO/SnO〈sub〉2〈/sub〉 heterojunction anode 〈em〉via〈/em〉 the acceleration effect induced by the built-in electric field (BEF). The resulting half cells LIBs consisting DCL@SnO/SnO〈sub〉2〈/sub〉 anode shows a high reversible specific capacity of 902.1 mAh g〈sup〉−1〈/sup〉 after 500 cycles at a current density of 1400 mA g〈sup〉−1〈/sup〉. The specific capacity of 347.04 mAh g〈sup〉−1〈/sup〉 was still maintained even at a high current density of 10 000 mA g〈sup〉−1〈/sup〉. Moreover, the maximum energy and power density of 125 W kg〈sup〉−1〈/sup〉 and 200 Wh kg〈sup〉−1〈/sup〉, respectively, were achieved from the half cells LIC comprising DCL@SnO/SnO〈sub〉2〈/sub〉 anode (LIC-DCL@SnO/SnO〈sub〉2〈/sub〉).〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉A hierarchical hollow SnO/SnO〈sub〉2〈/sub〉 heterostructure anode surrounded by a dual carbon layer (DCL@SnO/SnO〈sub〉2〈/sub〉) is prepared by a simple hydrothermal method using a single Sn precursor. The CNT-based inner carbon host layer is equipped by a nanotail CNT to form a tadpole-like structure. The ultrathin elastic amorphous outer carbon layer buffers the cyclic volume change of the SnO/SnO〈sub〉2〈/sub〉 heterostructure, while its natural properties could realize the formation of thin, instead of thick, solid-electrolyte interphase (SEI) layer to enhance e〈sup〉−〈/sup〉/Li〈sup〉+〈/sup〉 reversibility and transport kinetics during charge charge–discharge cycles. The p–n heterojunction created from SnO/SnO〈sub〉2〈/sub〉 heterostructure facilitates the creation of the built-in electric field (BEF) to promote e〈sup〉−〈/sup〉/Li〈sup〉+〈/sup〉 transport rate during charge–discharge cycling and to maintain a reversible high capacity at a high current density.〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0008622319306888-fx1.jpg" width="288" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Carbon, Volume 153〈/p〉 〈p〉Author(s): Chen Han, Xiaoguang Duan, Mingjie Zhang, Wenzhao Fu, Xuezhi Duan, Wenjie Ma, Shaomin Liu, Shaobin Wang, Xinggui Zhou〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Nanocarbon-catalyzed advanced oxidation processes for wastewater remediation are green and state-of-the-art methods, nevertheless, the origins of carbocatalysis remain unresolved. In this study, carbon nanotubes (CNTs) are employed as typical metal-free catalysts for catalytic peroxymonosulfate (PMS) activation and phenol oxidation. The surface chemistry and electronic properties of CNTs are deliberately tailored by liquid acid oxidation and subsequent thermal treatment. It is unveiled that the electron-rich carbon surface and carbonyl groups can affect organic adsorption capacity of the carbocatalysts and modulate persulfate activation in different catalytic manners. Furthermore, the relationship between the surface chemistry (oxygen functionality and electron density) and carbocatalysis is established, which is decisive to regulate the radical/nonradical pathways in the catalytic oxidation for water purification. This study provides new insights to carbon-catalyzed persulfate activation with manipulated reaction pathways and redox potentials.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0008622319306839-fx1.jpg" width="260" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: September 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Applied Thermal Engineering, Volume 160〈/p〉 〈p〉Author(s): Jiaxu Wang, Xuefeng Liu, Siwei Chen, Hanghang Jiang, Guanyu Fang, Wenjing Chen, Shiming Deng〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The current work study the heat dissipation characteristics and airflow distribution in a power cabin. By simplifying the cable structure, a 1:5 reduced-scale model was constructed based on the Archimedes number. Computational fluid dynamics (CFD) simulations were applied to the prototype power cabin. The 3D steady-state Reynolds average Navier-Stokes (RANS) equation is used to solve the ventilation flow, where the turbulence model is realizable k–ε. The CFD simulation of the prototype has been verified by the reduced-scale model. On this basis, several conclusions were drawn. The airflow distribution in the power cabin and cable arrangement cause a difference in the temperature distribution between the cables. The strong turbulence at the air inlet causes a significant temperature drop. The mechanical fan can effectively cool the cable to a certain extent, but cable temperature control should take into account the effects of ampacity and ventilation, as well as cable location.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: September 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Applied Thermal Engineering, Volume 160〈/p〉 〈p〉Author(s): Wenwu Zhou, Lin Yuan, Xin Wen, Yingzheng Liu, Di Peng〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The present study explored and examined the piezoelectric (PE) jet: an active cooling concept that can be actuated in demand, which had an oscillating flow and extremely low power consumption. The heat transfer and flow characteristics of the PE jet were quantified at various Reynolds numbers (〈em〉Re〈/em〉 = 5000, 10,000, 18,000) and spacings (〈em〉H〈/em〉/〈em〉D〈/em〉 = 4.5, 5.5, 6.5; corresponding gap 〈em〉G〈/em〉/〈em〉D〈/em〉 = 0.1, 1.1, 2.1). The temperature sensitive paint technique was used to study the heat transfer, and the particle image velocimetry technique was applied to resolve the flow characteristics and to further correlate the heat transfer results. Measured results show that the impingement cooling of the PE jet increased as the 〈em〉Re〈/em〉 increased and as the 〈em〉H〈/em〉/〈em〉D〈/em〉 decreased. Compared with a circular jet, the PE jet exhibited a greatly improved heat transfer at 〈em〉H〈/em〉/〈em〉D〈/em〉 = 4.5 (i.e., 〈em〉G〈/em〉 = 0.1〈em〉D〈/em〉), with a maximum of 20% enhancement in area-averaged 〈em〉Nu〈/em〉. Due to the fan oscillation, the turbulent kinetic energy level in the PE jet was significantly higher than in the circular jet, which greatly promoted the heat transfer at a narrow gap. In general, the new PE jet can provide superior heat transfer performance at a small gap and a high Reynolds number.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 World Development, Volume 123〈/p〉 〈p〉Author(s): Adriana Camacho, Emily Conover〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Small-scale farmers in developing countries often make production and sale decisions based on imprecise, informal, and out-of-date sources of information, such as family, neighbors, or tradition. Lack of timely and accurate information on climate and prices can lead to inefficiencies in the production, harvesting, and commercialization of agricultural products, which in turn can affect farmers’ revenues and well-being. We did a Randomized Controlled Trial (RCT) experiment with 500 small-scale farmers in a rural area of Colombia where there is nearly full mobile phone usage and coverage. Treated farmers received around 8 text messages per week with prices in the main markets for crops grown in the region, and customized weather forecasts. Compared to a control group, we find that treated farmers were more likely to report that text messages provide useful information for planting and selling, and more likely to always read their messages, indicating an increase in appreciation and use of this type of technology. We also found heterogeneous effects by farmer size. Smaller farmers try to make use of the intervention by planting more crops for which they have price information. Larger farmers seek new markets and increase conversations with other producers. Despite these positive effects, we do not find a significant difference in farmers reporting a price, price differential with the market price, or sale prices received. Our results indicate that farmers are amenable to learning and using new technologies, but that the introduction of these technologies do not always translate into short-run welfare improvements for them. Given the increased interest in incorporating information and communication technologies into agriculture, our findings indicate that prior to a large-scale implementation it is necessary to better understand what prevents farmers from more directly profiting from this new information.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 5 October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Chemical Geology, Volume 524〈/p〉 〈p〉Author(s): Mengxue Li, Haibo Liu, Tianhu Chen, Lin Wei, Can Wang, Wei Hu, Hanlin Wang〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The transformation of Al-substituted goethite in oxidative and reductive atmosphere, which models natural fire, was investigated in detail. Various characterization results indicated that Al-substituted goethite transformed into hematite in an oxidative atmosphere and magnetite followed by zero-valent iron in a reductive atmosphere. Interestingly, the substitution of Al for Fe not only changed the crystal morphology affecting crystal surface reactivity, but also restrained the transformation of goethite into hematite, magnetite and zero-valent iron. In addition, the Al in the goethite was embedded into the crystal structure of thermally formed hematite and magnetite, considerably influencing their surface reactivity. The macroscopic adsorption results indicated that the substitution of Al for Fe increased the adsorption capacity of goethite and the corresponding derivatives except zero-valent iron. For the same Al amount, the adsorption capacity followed an order of goethite 〉 hematite 〉 magnetite, implying a loss of phosphate in goethite-rich soil after experiencing natural fire. However, with increasing in temperature in the reductive atmosphere, Al-magnetite transformed into a mixture of Al-magnetite and zero-valent iron which displayed excellent phosphate adsorption capacities increasing to 1.21–5.96 mg/g. The phosphate adsorption behaviors to thermally formed products were fitted well by surface complexation modeling with five complexation sites, which were more obvious for goethite than for hematite and magnetite. These findings presented in this study represent significant progress toward an understanding of the migration, enrichment and transformation of phosphate in Al-substituted goethite-rich soil in cases experiencing natural fire.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: September 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Solid State Chemistry, Volume 277〈/p〉 〈p〉Author(s): Chen Chai, Caimei Fan, Jianxin Liu, Xiaochao Zhang, Yawen Wang, Rui Li, Donghong Duan, Yunfang Wang〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉In this work, a novel g-C〈sub〉3〈/sub〉N〈sub〉4〈/sub〉 modified Mn〈sub〉3〈/sub〉O〈sub〉4〈/sub〉 composite was synthesized and applied to activate peroxymonosulfate (PMS) for phenol degradation under simulated sunlight. We investigated the effect of solution initial pH and reaction temperature, meanwhile ascertaining the optimal molar ratio of Mn〈sub〉3〈/sub〉O〈sub〉4〈/sub〉 and g-C〈sub〉3〈/sub〉N〈sub〉4〈/sub〉 and the stability and reusability of the materials. The g-C〈sub〉3〈/sub〉N〈sub〉4〈/sub〉/Mn〈sub〉3〈/sub〉O〈sub〉4〈/sub〉 exhibited superior activity for PMS activation under simulated sunlight, 87.3% phenol degradation and 47.3% phenol mineralization at 60 min were achieved. The combination of Mn〈sub〉3〈/sub〉O〈sub〉4〈/sub〉 nanoparticles and g-C〈sub〉3〈/sub〉N〈sub〉4〈/sub〉 sheets results in a higher catalytic activity than pure Mn〈sub〉3〈/sub〉O〈sub〉4〈/sub〉 and g-C〈sub〉3〈/sub〉N〈sub〉4〈/sub〉. Furthermore, quenching experiments and electron spin resonance measurements (ESR) prove that phenol degradation by g-C〈sub〉3〈/sub〉N〈sub〉4〈/sub〉/Mn〈sub〉3〈/sub〉O〈sub〉4〈/sub〉/PMS system is primarily attributed to the generation of sulfate radicals, hydroxyl radicals, and superoxide radicals. A possible mechanism was proposed for phenol removal by g-C〈sub〉3〈/sub〉N〈sub〉4〈/sub〉/Mn〈sub〉3〈/sub〉O〈sub〉4〈/sub〉/PMS system under simulated sunlight. This work is intent to arise more interest about solar light for PMS activation and future research on water treatment.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0022459619303391-fx1.jpg" width="207" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 5 October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Chemical Geology, Volume 524〈/p〉 〈p〉Author(s): Xue-Feng Hu, Jing-Long Zhao, Pei-Feng Zhang, Yong Xue, Bo-Nian An, Fang Huang, Hui-Min Yu, Gan-Lin Zhang, Xiang-Jun Liu〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉To probe Fe isotopic signatures of the Quaternary Red Clay (QRC) in subtropical southeastern China, two QRC profiles located in southern Anhui Province, Southeast China, were studied. The whole profiles were generally in a narrow range in δ〈sup〉56〈/sup〉Fe of −0.040 ± 0.061‰—0.117 ± 0.048‰. The Yellow-brown Earth (YBE) and Uniform Red Clay (URC) of the upper profiles were similar in δ〈sup〉56〈/sup〉Fe to the Xiashu Loess along the Yangtze River, Southeast China, and the loess, paleosols and Tertiary red clay in the Chinese Loess Plateaus, Northwest China, as well as the baseline of terrestrial igneous rocks. The slight variation of δ〈sup〉56〈/sup〉Fe from the YBE to the URC suggests that the chemical weathering and rubification on the aerobic surface did not fractionate Fe isotopes significantly. The Reticulate Red Clay (RRC) underlying the YBE and URC fluctuated in δ〈sup〉56〈/sup〉Fe to some extent. The white veins separated from the lower RRC were depleted of Fe oxides and heavier in Fe isotopes, and the red veins, on the contrary, were isotopically lighter in Fe. δ〈sup〉56〈/sup〉Fe of the white veins, 0.345 ± 0.053‰ on average, was significantly higher than the bulk samples, 0.033 ± 0.044‰ on average, and the red veins, −0.021 ± 0.046‰ on average. This suggests that the reticulate textures of the RRC were formed by the reductive removal/re-precipitation of Fe due to the cyclical changes of redoxic conditions. Fe isotopic composition of the QRC was dominantly controlled by the redoxic mobility of Fe, rather than the degree of weathering. δ〈sup〉56〈/sup〉Fe of the profiles was not correlated with the paleoclimatic events, and thus cannot be used as a paleoclimatic proxy. The fractionation of Fe isotopes in the lower RRC, however, indicated the occurrence of over-humid paleoclimate with alternations between drought and wetness in Southern China during the Pleistocene.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: September 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Solid State Chemistry, Volume 277〈/p〉 〈p〉Author(s): Zhuo Dai Li, Huai Qiang Zhang, Xiao Hong Xiong, Feng Luo〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Covalent organic frameworks (COFs) represent an exciting new type of porous organic materials, which are constructed with organic building units via strong covalent bonds. Here in, the COF-2,4,6-Triformylphloroglucinol p-Phenylenediamine (COF-TpPa-1) was synthesized by solvothermal method for the removal of U(VI) from aqueous solution. Effects of pH, adsorption dose, contact time, uranium solution concentration, temperature and adsorption and desorption cycle on the efficiency of COF-TpPa-1 removal of U(VI) are investigated. SEM, XRD, TGA and FT-IR were employed to characterize the samples and analyze adsorption mechanism. The results manifested COF-TpPa-1 has the high adsorption capacity (〈em〉q〈/em〉〈sub〉m〈/sub〉 = 152 mg/g), quick adsorption kinetic, high selectivity, outstanding recycle performance and good resistance to acids, bases and high temperature.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0022459619303342-fx1.jpg" width="478" alt="Image 1" title="Image 1"〉〈/figure〉Covalent organic frameworks (COFs) represent an exciting new type of porous organic materials, which are constructed with organic building units via strong covalent bonds. In this study, the COF-2,4,6-Triformylphloroglucinol p-Phenylenediamine (COF-TpPa-1) was synthesized by solvothermal method for the removal of U(VI) from aqueous solution. The results manifested COF-TpPa-1 has the high adsorption capacity (〈em〉q〈/em〉〈sub〉m〈/sub〉 = 152 mg/g), quick adsorption kinetic, high selectivity, outstanding recycle performance and good resistance to acids, bases and high temperature.〈/p〉〈/div〉

Description: 〈p〉Publication date: September 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Solid State Chemistry, Volume 277〈/p〉 〈p〉Author(s): Tao E, Dan Ma, Shuyi Yang, Yudong Sun, Jiasheng Xu, Eui Jung Kim〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Zirconium dioxide loaded montmorillonite (ZrO〈sub〉2〈/sub〉-MMT) composites have been prepared using an ion-exchange process at room temperature followed by a thermal treatment. The as-prepared composites are used to adsorb Cr〈sup〉3+〈/sup〉 ions in the tanning wastewater with a lower initial Cr〈sup〉3+〈/sup〉 concentration, reducing residual Cr〈sup〉3+〈/sup〉 concentration to less than 1 mg L〈sup〉−1〈/sup〉. XRD, TEM, SEM-EDS and XPS analyses are made to explore the structure and morphology of the composites. ZrO〈sub〉2〈/sub〉 is found to load on the interlayer and surface of MMT. The adsorption process is appropriately described by the pseudo-second-order kinetic equation and Langmuir equation. The ZrO〈sub〉2〈/sub〉-MMT composites exhibit a better adsorption capacity than adsorption materials reported in the literature, and the maximum adsorption capacity for the initial Cr〈sup〉3+〈/sup〉 concentration of 10, 20, 30 mg L〈sup〉−1〈/sup〉 is as large as 142.86, 158.73 and 172.41 mg g〈sup〉−1〈/sup〉, respectively. The removal efficiency of ZrO〈sub〉2〈/sub〉-MMT for Cr〈sup〉3+〈/sup〉 remains above 92% after six cycles.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉A schematic diagram of the prepared ZrO〈sub〉2〈/sub〉-MMT composites: step 1 added Zr(SO〈sub〉4〈/sub〉)〈sub〉2〈/sub〉 solution to MMT slurry and stirred; step 2 added the NaOH solution (5 mol L〈sup〉−1〈/sup〉) to the mixture to achieve pH 7–8, stirred, centrifuged and dried at 50 °C; step 3 heat-treated for 4 h at 400 °C.〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0022459619303366-fx1.jpg" width="341" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: September 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Solid State Chemistry, Volume 277〈/p〉 〈p〉Author(s): Chen Tian, Qingshan Lu, Shifeng Zhao〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Design of low–cost and efficient materials with appropriate composition and configuration is desirable for supercapacitor electrode. In this work, hierarchical silica@manganese silicate core–shell spheres with controllable particle size and shell thickness are fabricated through a facile hydrothermal method. The monodispersed core–shell spheres dispaly the hierarchical structure composed of manganese silicate crystallites. The dependence of electrochemical performance on the particle size and the shell thickness is investigated. The finding demonstrates that the core–shell sphere prepared using small silica sphere possesses superior electrochemical properties. A specific capacitance of 297.3 F/g at a current density of 0.5 A/g is achieved. And the thick shell is also in favour of enhancing specific capacitance. The excellent surface–dependent electrochemical performance is associated with its distinctive hierarchical structure, which effectively shortens the ion/electron migration pathway and provides enough electroactive sites. The hierarchical core–shell spheres can be potentially applied in low–cost electrode for supercapacitor.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉Monodispersed and hierarchical silica@manganese silicate core–shell spheres prepared by a hydrothermal method exhibit the controllable diameter, shell thickness and excellent electrochemical performance.〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0022459619303408-fx1.jpg" width="500" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: September 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Applied Geochemistry, Volume 108〈/p〉 〈p〉Author(s): Irina Drozdova, Natalya Alekseeva-Popova, Vladimir Dorofeyev, Jaume Bech, Alla Belyaeva, Núria Roca〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Native plant species growing on contaminated sites in an urban environment successfully develop under strong anthropogenic pressure and thereby may have the potential for phytoremediation. The concentrations of potentially toxic metals were measured in leaves, roots, stems, and inflorescences of fifteen Brassicaceae plant species from the urban park of Botanical Garden of Komarov Botanical Institute. The potential of phytoextraction and phytostabilization of the species was evaluated considering the concentration of Cd, Cu, Ni, Pb, Zn in the plant organs, and the bioconcentration factor (BCF) and the translocation factor (TF). The metal content in plant organs varied with plant species. The study of metal accumulation in plants showed that 〈em〉Brassica campestris〈/em〉 has the potential for the simultaneous phytoextraction of three metals Zn, Cd, and Cu, and 〈em〉Rorippa palustris〈/em〉 – of two metals Zn and Cd. According to received data, species 〈em〉Sinapis arvensis〈/em〉 and 〈em〉Thlaspi arvense〈/em〉 can be considered adequate candidates for soil Zn and Pb phytostabilization and soil conservation.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of the Mechanics and Physics of Solids, Volume 131〈/p〉 〈p〉Author(s): Amir Ashkan Mokhtari, Yan Lu, Ankit Srivastava〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉In this paper, we consider the operator properties of various phononic eigenvalue problems. We aim to answer some fundamental questions about the eigenvalues and eigenvectors of phononic operators. These include questions about the potential real and complex nature of the eigenvalues, whether the eigenvectors form a complete basis, what are the right orthogonality relationships, and how to create a complete basis when none may exist at the outset. In doing so we present a unified understanding of the properties of the phononic eigenvalues and eigenvectors which would emerge from any numerical method employed to compute such quantities. We show that the phononic problem can be cast into linear eigenvalue forms from which such quantities as frequencies, wavenumbers, and desired components of wavevectors can be directly ascertained without resorting to searches or quadratic eigenvalue problems and that the relevant properties of such quantities can be determined apriori through the analysis of the associated operators. We further show how the Plane Wave Expansion (PWE) method may be extended to solve each of these eigenvalue forms, thus extending the applicability of the PWE method to cases beyond those which have been considered till now. The theoretical discussions are supplemented with supporting numerical calculations. The techniques and results presented here directly apply to wave propagation in other periodic systems such as photonics.〈/p〉〈/div〉

Description: 〈p〉Publication date: 15 December 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Hazardous Materials, Volume 380〈/p〉 〈p〉Author(s): Gautam Kumar Sarma, Aslam Khan, Ahmed Mohamed El-Toni, Md. Harunar Rashid〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Herein, we report for the first time, the synthesis of CuO-Nd(OH)〈sub〉3〈/sub〉 nanocomposites via a co-precipitation method coupled with the hydrothermal aging process. Varying the pH of the reaction medium, the shape of the nanocomposites could be controlled which determines their surface areas. These CuO-Nd(OH)〈sub〉3〈/sub〉 nanocomposites exhibit very high adsorption capacity with successful removal of ∼ 97% of brilliant blue G (BBG) from water in 180 min under ambient condition. The adsorption process primarily follows Lagergren pseudo-first-order kinetics. The Langmuir isotherm model fits well with a very high monolayer adsorption capacity of 394.1 mg g〈sup〉−1〈/sup〉 at 30 °C. The mechanistic study supports chemisorption-type adsorption between the dye molecule and the adsorbent. Regeneration of the spent adsorbent makes the whole process cyclic and eco-friendly.〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0304389419307915-ga1.jpg" width="297" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 15 December 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Hazardous Materials, Volume 380〈/p〉 〈p〉Author(s): Junchao Zhao, Zhitao Yin, Muhammad Usman Shahid, Haoran Xing, Xudong Cheng, Yangyang Fu, Song Lu〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The re-ignition of pool fires is a common hazard phenomenon in fire extinguishing. Dry chemicals with oleophobicity may solve this problem because powders can float on the oil surface and prevent evaporation of fuel pool. In this research, MAPP (modified ammonium polyphosphate) with superhydrophobicity, oleophobicity, and higher chemical activity is prepared which can quickly quench pool fires and provide longer protection. The activation indexes of MAPP for water, diesel, aviation kerosene and gasoline are 98.5%, 87.4%, 98.7% and 98.4%, respectively. Lower activation energy of MAPP means that it will show higher chemical activity in fire. The fire-extinguishing performance of MAPP is much higher than that of Commercial UDCA (ultra-fine dry chemical agent) during fire experiments. After extinguished by MAPP, the fuel pool is hard to be re-ignited. The significance of this study is to propose a new strategy for preventing the re-ignition of pool fires.〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0304389419305497-ga1.jpg" width="492" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 15 December 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Hazardous Materials, Volume 380〈/p〉 〈p〉Author(s): L. Sbardella, I. Velo-Gala, J. Comas, I. Rodríguez-Roda Layret, A. Fenu, W. Gernjak〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉 〈p〉Ultraviolet radiation (UV)-activated peroxydisulfate (PDS) and peroxymonosulfate (PMS) advanced oxidation processes were examined for their capacity to remove nine pharmaceutically active compounds (PhACs) from secondary effluent. The effect of operational parameters (initial oxidant concentration, UV exposure time, pH, common coexisting anions and effluent organic matter (EfOM)) on UV/PDS and UV/PMS treatment efficiency was investigated in a collimated beam device housing a low-pressure mercury UV lamp emitting light at 253.7 nm.〈/p〉 〈p〉Both AOPs achieved high removals (〉90%) when applied to pure water. Under otherwise similar conditions the removal percentage fell by 20–30% due to the scavenging of effluent organic matter (EfOM) in secondary effluent. Finally, eliminating EfOM but maintaining the inorganic composition, the radical scavenging effect was reduced and 98.3% and 85.6% average removals were obtained by UV/PDS and UV/PMS, respectively.〈/p〉 〈p〉Increasing pH improved degradation of several PhACs containing amine groups. Higher oxidant dosages created only a significant benefit in UV/PDS. The chloride anion produced a negligible effect on both processes, while higher nitrate concentrations increased removal percentage but did not affect degradation rate constants. Finally and surprisingly, the addition of bicarbonate had the strongest positive impact on the degradation kinetics observed, even stronger than the elimination of EfOM from secondary effluent.〈/p〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0304389419308222-ga1.jpg" width="500" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Biomaterials, Volume 218〈/p〉 〈p〉Author(s): Yuwei Liu, Biao Kuang, Benjamin B. Rothrauff, Rocky S. Tuan, Hang Lin〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Mesenchymal stem cells (MSCs) embedded in their secreted extracellular matrix (mECM) constitute an exogenous scaffold-free construct capable of generating different types of tissues. Whether MSC-mECM constructs can recapitulate endochondral ossification (ECO), a developmental process during 〈em〉in vivo〈/em〉 skeletogenesis, remains unknown. In this study, MSC-mECM constructs are shown to result in robust bone formation both 〈em〉in vitro〈/em〉 and 〈em〉in vivo〈/em〉 through the process of endochondral ossification when sequentially exposed to chondrogenic and osteogenic cues. Of interest, a novel trypsin pre-treatment was introduced to change cell morphology, which allowed MSC-mECM constructs to undergo the N-cadherin-mediated developmental condensation process and subsequent chondrogenesis. Furthermore, bone formation by MSC-mECM constructs were significantly enhanced by the ECO protocol, as compared to conventional 〈em〉in vitro〈/em〉 culture in osteogenic medium alone. This was designed to promote direct bone formation as seen in intramembranous ossification (IMO). The developmentally informed method reported in this study represents a robust and efficacious approach for stem-cell based bone generation, which is superior to the conventional osteogenic induction procedure.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 1 October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Electrochimica Acta, Volume 319〈/p〉 〈p〉Author(s): Xiao-Hu Dai, Hao-Xiang Fan, Jia-Jia Zhang, Shi-Jie Yuan〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Pyrolysis gradually becomes a promising green method to dispose the sewage sludge who has brought serious problems to environment. In this study, hierarchical porous hollow carbon nanospheres are directly obtained by specific carbonization/activation procedures using sewage sludge as the only precursor for the first time. The resultant carbon possesses tailor-made hierarchically porous structure with larger surface area (1518.40 m〈sup〉2〈/sup〉 g〈sup〉−1〈/sup〉), high pore volume (1.21 cm〈sup〉3〈/sup〉 g〈sup〉−1〈/sup〉), and rich oxygenic functional groups, which is favorable for lithium ion diffusion and can better enhance the ionic conductivity in an electrode system. As anode for li-ion battery, the carbon displays superior discharge capacity, which reaches 1168.9 mAh g〈sup〉−1〈/sup〉 at 0.1 A g〈sup〉−1〈/sup〉 and 287.1 mAh g〈sup〉−1〈/sup〉 at 2 A g〈sup〉−1〈/sup〉. And the capacitance retention is 98.7% over 100 cycles at 0.1 A g〈sup〉−1〈/sup〉. Therefore, it is anticipated that such a pollutants-derived carbon can facilitate the development of new green and sustainable pathways for the construction and design of well-defined porous carbon nanospheres to ease energy and environmental issues.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0013468619313313-fx1.jpg" width="245" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: Available online 5 July 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Bioorganic & Medicinal Chemistry Letters〈/p〉 〈p〉Author(s): Gyeong Han Jeong, Jae-Hyeon Cho, Tae Hoon Kim〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Convenient structure modification of (+)-catechin (〈strong〉1〈/strong〉) induced by nonthermal dielectric barrier discharge (DBD) plasma treatment afforded three novel methylene-linked flavan-3-ol oligomers, methylenetetracatechin (〈strong〉2〈/strong〉), methylenetricatechin (〈strong〉3〈/strong〉), and methylenedicatechin (〈strong〉4〈/strong〉), together with two known catechin dimers, 〈em〉bis〈/em〉 8,8′-catechinylmethane (〈strong〉5〈/strong〉) and 〈em〉bis〈/em〉 6,8′-catechinylmethane (〈strong〉6〈/strong〉). The structures of the three new catechin oligomers 〈strong〉2〈/strong〉–〈strong〉4〈/strong〉 with methylene bridges were elucidated by detailed 1D- and 2D-NMR analysis, and the absolute configurations were established by the observation of circular dichroism (CD). The novel products 〈strong〉2〈/strong〉 and 〈strong〉3〈/strong〉 showed significantly enhanced anti-adipogenic capacities against both pancreatic lipase and differentiation of 3T3-L1 preadipocytes compared to the parent (+)-catechin.〈/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-S0960894X19304536-ga1.jpg" width="500" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 1 September 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Bioorganic & Medicinal Chemistry, Volume 27, Issue 17〈/p〉 〈p〉Author(s): Miriam Rossi, Francesco Caruso, Ilaria Costanzini, Carmen Kloer, Aron Sulovari, Elena Monti, Marzia Gariboldi, Emanuela Marras, Neduri V. Balaji, Modukuri V. Ramani, Gottumukkala V. Subbaraju〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The antiproliferative action of hispolon derivatives is stronger than that of related curcumin against several tumor cell lines. Hispolon size, smaller than curcumin, fits better than curcumin into the active site of HDAC6, an enzyme involved in deacetylation of lysine residues. HDACs are considered potential targets for tumor drug discovery and hydroxamates are known inhibitors of HDACs. One of them, SAHA (Vorinostat) is used in clinical studies. Investigations into possible mechanisms for hispolon derivatives active against the HCT116 colon tumor cell line are done after examining the structural results obtained from hispolon X-ray crystal structures as well as performing associated computational docking and Density Functional Theory techniques on HDAC6. These studies show preference for the HDAC6 active site by chelating the Zn center, in contrast with other ineffective hispolon derivatives, that establish only a single bond to the metal center. Structure activity relationships make clear that hydrogenation of the hispolon bridge also leads to single bond (non chelate) hispolon-Zn binding, and consistently nullifies the antiproliferative action against HCT116 tumor.〈/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-S0968089619301907-ga1.jpg" width="366" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: Available online 5 July 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Bioorganic & Medicinal Chemistry Letters〈/p〉 〈p〉Author(s): Yasushi Ogasawara, Yo Nakagawa, Chitose Maruyama, Yoshimitsu Hamano, Tohru Dairi〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Mitomycins, produced by several 〈em〉Streptomyces〈/em〉 strains, are potent anticancer antibiotics that comprise an aziridine ring fused to a tricyclic mitosane core. Mitomycins have remarkable ability to crosslink DNA with high efficiency. Despite long clinical history of mitomycin C, the biosynthesis of mitomycins, especially mitosane core formation, remains unknown. Here, we report 〈em〉in vitro〈/em〉 characterization of three proteins, MmcB (acyl carrier protein), MitE (acyl AMP ligase), and MitB (glycosyltransferase) involved in mitosane core formation. We show that 3-amino-5-hydroxybenzoic acid (AHBA) is first loaded onto MmcB by MitE at the expense of ATP. MitB then catalyzes glycosylation of AHBA-MmcB with uridine diphosphate-〈em〉N〈/em〉-acetylglucosamine (UDP-GlcNAc) to generate a key intermediate, GlcNAc-AHBA-MmcB, which contains all carbon and nitrogen atoms of the mitosane core. These results provide important insight into mitomycin biosynthesis.〈/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-S0960894X19304548-ga1.jpg" width="490" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 15 August 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Bioorganic & Medicinal Chemistry, Volume 27, Issue 16〈/p〉 〈p〉Author(s): Zahra Mojallal-Tabatabaei, Parham Foroumadi, Mahsa Toolabi, Fereshteh Goli, Setareh Moghimi, Sussan Kaboudanian-Ardestani, Alireza Foroumadi〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The development of novel leishmanicidal agents that are capable of being replaced by the available therapeutic options has become a priority. In the present study, the synthesis and leishmanicidal activity of a series of 5-(nitroheteroaryl-2-yl)-1,3,4-thiadiazole derivatives are described. All compounds appeared to be potent anti-leishmanial agents against both promastigote and amastigote forms of 〈em〉Leishmania major〈/em〉 (〈em〉L. major)〈/em〉. Amongst the synthesized compounds, 2-([1,4′-bipiperidin]-1′-yl)-5-(5-nitrofuran-2-yl)-1,3,4-thiadiazole (〈strong〉IIa〈/strong〉) and 1-(5-(1-methyl-5-nitro-1〈em〉H〈/em〉-imidazole-2-yl)-1,3,4-thiadiazol-2-yl)-4-(piperidine-1-yl) piperidine (〈strong〉IIc〈/strong〉) are the most effective. Infection index was statistically declined in the presence of all compounds. The analysis of redox-related factors revealed that exposure of 〈em〉L. major〈/em〉 cells to 〈strong〉IIa〈/strong〉 and 〈strong〉IIc〈/strong〉 led to an increase in reactive oxygen species (ROS). Furthermore, two compounds were able to increase ROS and NO levels in infected macrophages in a dose-independent manner. In addition, we showed that these compounds induced cell death in promastigotes. Altogether, our results indicated the anti-leishmanial potential of 〈strong〉IIa〈/strong〉 and 〈strong〉IIc〈/strong〉 is mediated by apoptosis through an imbalance in the redox system resulting in the elevation of ROS. This new class of compound seems to hold great promise for the development of new and useful anti-leishmanial 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-S0968089619303700-ga1.jpg" width="335" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: Available online 6 July 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Tetrahedron Letters〈/p〉 〈p〉Author(s): Mahender Khatravath, Naveen Kumar Mallurwar, Saidulu Konda, Jagan Gaddam, Pallavi Rao, Javed Iqbal, Prabhat Arya〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉A practical stereoselective synthesis of the central C1–C10 fragment of eribulin and its two diastereomeric analogues is developed. Our approach relied on the use of 〈span〉l〈/span〉-ascorbic acid as the starting material which allowed accessing a key intermediate with a syn diol moiety (C9 and C10 of eribulin) and a carboxylic ester group. A functionalized six membered lactone having several required hydroxyl groups was then obtained. In a number of steps, the lactone was converted to an intermediate for our key 〈em〉oxa〈/em〉-Michael reaction. A regio- and stereocontrolled intramolecular oxa〈em〉-〈/em〉Michael reaction completed the synthesis of the C1–11 fragment having a trans-fused tetrahydropyrans with the exact stereochemistry of various hydroxyl groups, as in eribulin.〈/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-S0040403919306525-ga1.jpg" width="500" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 25 July 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Tetrahedron Letters, Volume 60, Issue 30〈/p〉 〈p〉Author(s): 〈/p〉

Description: 〈p〉Publication date: 25 July 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Tetrahedron Letters, Volume 60, Issue 30〈/p〉 〈p〉Author(s): 〈/p〉

Description: 〈p〉Publication date: October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Petroleum Science and Engineering, Volume 181〈/p〉 〈p〉Author(s): Zhihua Wang, Ye Bai, Hongqi Zhang, Yang Liu〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Waxy crude oil emulsions exhibit gelation behavior, with nucleation observed within a certain temperature range. A kinetic model was developed and validated based on the thermal parameters obtained from differential scanning calorimetry cooling thermograms, and the nucleation rates of various water-in-waxy crude oil emulsions were determined in the temperature range in which gelation occurs. Although temperature had a dominant effect on the gelation and nucleation behavior of waxy crude oil emulsions, the nucleation rate also increased as the water volume fraction in the emulsion increased. Emulsified water droplets with smaller radii can be completely covered by wax particles, inducing a greater nucleation rate. Subjecting the emulsions to a greater shearing strength also increased the nucleation rate. This study provided new insights into the nucleation processes that occur during the formation of waxy crude oil emulsion gels and, in particular, the role of the emulsification properties.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0920410519306424-fx1.jpg" width="496" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: Available online 5 July 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Tetrahedron Letters〈/p〉 〈p〉Author(s): Vladislav Y. Korotaev, Igor B. Kutyashev, Alexey Y. Barkov, Yuliya S. Rozhkova, Irina V. Plekhanova, Yurii V. Shklyaev, Vyacheslav Y. Sosnovskikh〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Ferrocene analogues of pyrrolo[2,1-〈em〉a〈/em〉]isoquinoline alkaloids, 2-(trifluoromethyl)-5,6-dihydroferroceno[〈em〉g〈/em〉]indolizine and 6-(trifluoromethyl)-8,9-dihydro-6〈em〉H〈/em〉-chromeno[4,3-〈em〉b〈/em〉]ferroceno[〈em〉g〈/em〉]indolizines, were obtained in 44–65% yield 〈em〉via〈/em〉 the Grob reaction between 1-nitro-1-(2,2,2-trifluoroethylidene)alkanes or 3-nitro-2-(trifluoromethyl)-2〈em〉H〈/em〉-chromenes and 1-alkyl-3,4-dihydroferroceno[〈em〉c〈/em〉]pyridines in 2-propanol at reflux.〈/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-S0040403919306537-ga1.jpg" width="500" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Petroleum Science and Engineering, Volume 181〈/p〉 〈p〉Author(s): Ulf Jakob F. Aarsnes, Nathan van de Wouw〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The present paper studies the effect of an axial elastic tool (known as a shock sub), mounted downhole in the drill-string, on the occurrence of axial and torsional self-excited vibrations. In particular, we evaluate the feasibility of stabilizing the axial dynamics, dominated by a bilateral (feedback) coupling between the bit-rock interaction and the drill-string wave-equations, through the insertion of a passive down-hole tool. We consider the problem of unwanted drill-string vibrations and explain how these vibrations relate to the so-called axial instability using a distributed parameter (infinite dimensional) model. The equations describing the feedback system causing this instability are derived and then extended to accommodate for the inclusion of the effect of the shock sub. Conditions for the design parameters of the shock sub needed to avoid axial instability are then derived and their practical feasibility are considered.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 25 July 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Tetrahedron Letters, Volume 60, Issue 30〈/p〉 〈p〉Author(s): 〈/p〉

Description: 〈p〉Publication date: October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Petroleum Science and Engineering, Volume 181〈/p〉 〈p〉Author(s): S. Mohammadi, M. Papa, E. Pereyra, C. Sarica〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Mechanistic modeling is one of the most popular approaches for the prediction of flow pattern, pressure gradient and liquid holdup in multiphase flow problems. Mechanistic models utilize the mass and momentum conservative equations in combination with a set of closure relationships. These closures, which are developed based on specific experimental setups, considerably affect the performance of the mechanistic models. Moreover, new closure relationships continue to be developed to improve the current mechanistic models. Thus, there is a need for a tool that allows the selection of a set of closure relationships for a given set of conditions. In this direction, this paper presents a methodology that relies on a genetic algorithm to search and select a set of closure relationships for a given experimental (field data) that minimize the error between measured and predicted pressure gradient. The results show the applying the genetic algorithm can improve the performance of the mechanistic model by about 277% when compared to selections of closure relationships made by a subject matter expert for the given data set.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Acta Astronautica, Volume 164〈/p〉 〈p〉Author(s): Hao-Yang Peng, Wei-Dong Liu, Shi-Jie Liu, Hai-Long Zhang, Wei-Yong Zhou〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Methane-air Continuous Rotating Detonation (CRD) has been firstly achieved in this paper in the hollow chamber with a Laval nozzle, and the diameter of the chamber is just 100 mm. The contraction ratio of the Laval nozzle is a key factor for the CRD realization. CRD can only be obtained when the contraction ratio is no less than 4, but its ER operating range decreases in the increase of contraction ratio from 4 to 10. For all the success cases, the average propagation frequency and velocity are in the ranges of 5.32–5.65 kHz and 1670.48–1774.10 m/s, respectively, and the velocity deficits are less than 10%. Based on the high-speed photography images, the approach of chemiluminescence intensity integral is proposed in this paper, and the propagation characteristics of the flame are analyzed quantitatively. The propagation velocities of the flame and shock wave are agreed well with each other, indicating that the typical feature of detonation wave, i.e., the coupling of the flame and the shock wave, is verified quantitatively.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: Available online 5 July 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Acta Astronautica〈/p〉 〈p〉Author(s): Jie Huang, Wei-Xing Yao, Ning Qin〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The spiked blunt body is usually adopted to reduce the aerodynamic heating of hypersonic vehicles. In this paper, the heat reduction mechanism of hypersonic spiked blunt body with installation angle at large angle of attack is studied by the CFD numerical method. The AUSM+ scheme and Menter's SST 〈em〉k〈/em〉-〈em〉ω〈/em〉 turbulent model are adopted for the spatial discretization and turbulent simulation respectively. The results show that the maximum wall heat flux of blunt body is sensitive to the angle of attack. The increase of angle of attack causes the aerodynamic heating to rise sharply. The installation angle of the spike can effectively reduce the maximum heat flux of blunt body at large angle of attack, which is very beneficial to the thermal protection of blunt body. There is an optimal installation angle to minimize the maximum heat flux of blunt body. The optimal installation angle is about 1.5° greater than the angle of attack. All the investigations in this paper show the feasibility and advantages of spiked blunt body with installation angle in the engineering applications.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: September 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Applied Thermal Engineering, Volume 160〈/p〉 〈p〉Author(s): Sanaz Tabasi, Hossein Yousefi, Younes Noorollahi, Mohamad Aramesh〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉In this paper, the performance of a photovoltaic panel integrated with a reflecting mirror is investigated. In this regard, the effects of panel and mirror tilt angles, and the mirror length on the system performance are modeled. The cell temperature rises have also been considered. Moreover, by a 3D model, the lighting and shading statuses are studied in detail, and all the possible conditions are presented and modeled. The resulting model can calculate the amount of incident solar energy on the panel and the generated electrical power in every moment during a year. This amount is dependent on the system configuration and capacity and its location. A 250-W photovoltaic panel and the city of Tehran have been considered the basics of calculations to assess the model results. By employing the genetic algorithm method, the optimum configuration has been found to have 69.084° and 0° tilt angles for the panel and the mirror, respectively, at the mirror length of 2 m. This configuration can generate 2.38 GJ (613.89 kWh) of electrical energy annually. It was also found that the optimum configuration had 0.024 GJ of annual energy losses due to the effects of cell temperature rise.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: September 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Applied Thermal Engineering, Volume 160〈/p〉 〈p〉Author(s): Su Min Hoi, An Liang Teh, Ean Hin Ooi, Irene Mei Leng Chew, Ji Jinn Foo〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The flow across the plate-fin heat sink under the influence of 2D planar space-filling square fractal grid-induced turbulence at Reynolds number 〈em〉Re〈sub〉Dh〈/sub〉〈/em〉 of 2.0 × 10〈sup〉4〈/sup〉 is numerically characterized. Fractal thickness ratio 〈em〉t〈sub〉r〈/sub〉〈/em〉, plate-fin inter-fin distance 〈em〉δ〈/em〉 and grid-fin separation 〈em〉ℓ〈/em〉 are numerically explored and optimized via Response Surface Optimization (RSO) with the objective of maximizing the Nusselt number 〈em〉Nu〈/em〉. Results reveal that, thanks to highly interactive, small and comparable turbulence length scale 〈em〉L〈sub〉t〈/sub〉〈/em〉, strong turbulence intensity 〈em〉T〈sub〉u〈/sub〉〈/em〉 and high velocity adjacent to the fin surfaces, thermal dissipation of plate-fin heat sink enhances significantly. An optimum fractal grid and plate-fin geometrical combination having 〈em〉t〈sub〉r〈/sub〉〈/em〉 = 9.77, 〈em〉δ〈/em〉 = 0.005 m and 〈em〉ℓ〈/em〉 = 0.01 m is proposed. It delivers 〈em〉Nu〈/em〉 of 3661.0 which is 6.1% and 16.3% greater than the reference case and least favorable configuration, respectively. Sensitivity analysis discovered that 〈em〉δ〈/em〉 effectively dominates the thermal dissipation improvement while 〈em〉t〈sub〉r〈/sub〉〈/em〉 contributes the most on the pressure drop. Interestingly, fractal grid may not necessarily augmenting plate-fin forced convective heat transfer. Without proper-tuning the fluid flow structures within the fins may worsen the thermal dissipation instead of strengthening it. In short, the interaction between plate-fin heat sink and the fluid flow structures within the fins contributes greatly to heat transfer performance.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 World Development, Volume 123〈/p〉 〈p〉Author(s): Alwin Keil, Archisman Mitra, Amit K. Srivastava, Andrew McDonald〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Sustainable intensification (SI) approaches to agricultural development are urgently needed to meet the growing demand for crop staples while protecting ecosystem services and environmental quality. However, SI initiatives have been criticized for neglecting social welfare outcomes. A recent review found that better-off farmers benefitted disproportionately from SI and highlighted the dearth of studies assessing the equity of outcomes. In this study, we explore the social inclusiveness of zero-tillage (ZT) wheat adoption in Bihar, India. ZT is a proven SI technology for enhancing wheat productivity while boosting profitability and reducing greenhouse gas emissions from agricultural machinery in the densely populated Indo-Gangetic Plains. With an average landholding size of 0.39 ha, most farmers in Bihar depend on custom-hiring services to access the technology. While service provision models should foster inclusive growth by reducing financial barriers to technology adoption, early evidence suggested that smallholders remained at a disadvantage. Building on this previous research, we use a panel dataset from 961 wheat-growing households that spans a six-year period to analyze ZT adoption dynamics over time while accounting for the role of social networks and access to service provision. Using a heckprobit approach to correct for non-exposure bias, we compare determinants of ZT awareness and use in 2012 and 2015. We apply a multinomial logit model to identify determinants of early adoption, recent adoption, non-adoption, and dis-adoption. Furthermore, we explore the quality of ZT services as an additional dimension of socially-inclusive technology access. We find that the strong initial scale bias in ZT use declined substantially as awareness of the technology increased and the service economy expanded. Land fragmentation replaced total landholding size as a significant adoption determinant, which also affected the quality of ZT services received. Hence, farmers with small but contiguous landholdings appear to have gained a significant degree of access over time. We conclude that early-stage assessments of SI may be misleading, and that private sector-based service provision can contribute to socially inclusive development outcomes as markets mature.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 World Development, Volume 123〈/p〉 〈p〉Author(s): Chiara Ravetti, Mare Sarr, Daniel Munene, Tim Swanson〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉This paper analyses the ways in which ethnic identity and labour institutions shape favouritism and discrimination among workers. We conduct a lab experiment in the field with South African coal miners from various ethnic groups and with different trade union membership status. Our analysis suggests that union identity and ethnic identity are two social constructs that operate in a distinct and opposite fashion. Unionization acts as a factor of workers solidarity beyond the confine of union membership. Conversely, ethnicity operates as the linchpin through which discrimination among workers is infused not only between ethnic majority and minorities, but also within the majority group itself. We find that the widespread practice of subcontracting in the mining sector exacerbates ethnic discrimination among workers both between and within ethnic groupings.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: September 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Applied Thermal Engineering, Volume 160〈/p〉 〈p〉Author(s): Mark Baldry, Victoria Timchenko, Chris Menictas〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Metal additive manufacturing technologies are increasingly being adopted for rapid prototyping and to build geometrically complex designs for thermal management. This paper develops and experimentally validates a numerical model to design a high performance, small-scale heat sink for use with a thermoelectric cooling cap. The design was constrained by a heat load of 2.15 W, and a target average base temperature of 45 °C as a compromise between avoiding burn injury and reducing heat dissipation requirements. Over successive numerical iterations, an optimal natural convection heat sink was developed with an estimated thermal resistance of 10.9  K·W〈sup〉−1〈/sup〉 and base temperature of 44.4 °C. This design featured an internal cavity in a tapered pin array, and was able to achieve a steady state base temperature that was 11.7 °C cooler than a conventional design, with 51% less surface area and significantly less material.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 World Development, Volume 123〈/p〉 〈p〉Author(s): Vanesa Jordá, Miguel Niño-Zarazúa〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Despite the growing interest in global inequality, assessing inequality trends is a major challenge because individual data on income or consumption is not often available. Nevertheless, the periodic release of certain summary statistics of the income distribution has become increasingly common. Hence, grouped data in form of income shares have been conventionally used to construct inequality trends based on lower bound approximations of inequality measures. This approach introduces two potential sources of measurement error: first, these estimates are constructed under the assumption of equality of incomes within income shares; second, the highest income earners are not included in the household surveys from which grouped data is obtained. In this paper, we propose to deploy a flexible parametric model, which addresses these two issues in order to obtain a reliable representation of the income distribution and accurate estimates of inequality measures. This methodology is used to estimate the recent evolution of global interpersonal inequality from 1990 to 2015 and to examine the effect of survey under-coverage of top incomes on the level and direction of global inequality. Overall, we find that item non-response at the top of the distribution substantially biases global inequality estimates, but, more importantly, it might also affect the direction of the trends.〈/p〉〈/div〉 〈/div〉

Description: Neurotoxins are among the main components of scorpion and snake venoms. Scorpion neurotoxins affect voltage‐gated ion channels, while most snake neurotoxins target ligand‐gated ion channels, mainly nicotinic acetylcholine receptors (nAChRs). We report that scorpion venoms inhibit α‐bungarotoxin binding to both muscle‐type nAChR from Torpedo californica and neuronal human α7 nAChR. Toxins inhibiting nAChRs were identified as OSK‐1 (α‐KTx family) from Orthochirus scrobiculosus and HelaTx1 (κ‐KTx family) from Heterometrus laoticus, both being blockers of voltage‐gated potassium channels. With an IC50 of 1.6 μm, OSK1 inhibits acetylcholine‐induced current through mouse muscle‐type nAChR heterologously expressed in Xenopus oocytes. Other well‐characterized scorpion toxins from these families also bind to Torpedo nAChR with micromolar affinities. Our results indicate that scorpion neurotoxins present target promiscuity.

Description: 〈p〉Publication date: November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 World Development, Volume 123〈/p〉 〈p〉Author(s): Ben Siegelman, Nora Haenn, Xavier Basurto〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉This paper relates how fishermen in San Evaristo on Mexico’s Baja peninsula employ fabrications to strengthen bonds of trust and navigate the complexities of common pool resource extraction. We argue this trickery complicates notions of social capital in community-based natural resource management, which emphasize communitarianism in the form of trust. Trust, defined as a mutual dependability often rooted in honesty, reliable information, or shared expectations, has long been recognized as essential to common pool resource management. Despite this, research that takes a critical approach to social capital places attention on the activities that foster social networks and their norms by arguing that social capital is a process. A critical approach illuminates San Evaristeño practices of lying and joking across social settings and contextualizes these practices within cultural values of harmony. As San Evaristeños assert somewhat paradoxically, for them “lies build trust.” Importantly, a critical approach to this case study forces consideration of gender, an overlooked topic in social capital research. San Evaristeña women are excluded from the verbal jousting through which men maintain ties supporting their primacy in fishery management. Both men’s joke-telling and San Evaristeños’ aversion to conflict have implications for conservation outcomes. As a result, we use these findings to help explain local resistance to outsiders and external management strategies including land trusts, fishing cooperatives, and marine protected areas.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: September 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Applied Thermal Engineering, Volume 160〈/p〉 〈p〉Author(s): Nae-Hyun Kim, Cheol-Hwan Kim, Yousaf Shah, Wei Li〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉In a parallel flow heat exchanger, significant mal-distribution of flow occurs due to phase separation. In this study, various insert devices (perforated tube, perforated tube with perforated plate, orifice and perforated tube, concentric perforated tube) were investigated to obtain an improved flow distribution in a 36 channel parallel flow heat exchanger. The test section was made to closely simulate an actual heat exchanger. Tests were conducted for upward flow for the mass flux from 57 to 241 kg m〈sup〉−2〈/sup〉 s〈sup〉−1〈/sup〉 and quality from 0.2 to 0.4 using R-410A. Of the investigated insert devices, concentric perforated tube yielded the best flow distribution. Insertion of the concentric perforated tube reduced the thermal degradation from 61% to 14%. Furthermore, the preferred number of holes of the concentric perforated tube was dependent on the mass flux. At a low mass flux, an insert having small number of holes was preferred, whereas the reverse was true at a high mass flux. At a low mass flux, the effect of inlet vapor quality on flow distribution was significant. At a high mass flux, however, the effect of vapor quality on flow distribution was minimal. Possible explanations on the flow distribution behavior were provided through flow visualization in the header.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 3 September 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Biochemical and Biophysical Research Communications, Volume 516, Issue 4〈/p〉 〈p〉Author(s): Lifang Cui, He Zhao, Yujun Yin, Chao Liang, Xiaolong Mao, Yingzheng Liu, Qilin Yu, Mingchun Li〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉〈em〉Candida albicans〈/em〉 is an important opportunistic pathogenic fungus in the human body. It is a common microbe inhabiting on the mucosa surfaces of healthy individuals, but may cause infections when the host immune system is weak. Autophagy is a “self-eating” process in eukaryotes, which can recover and utilize damaged organelles and misfolded proteins. Here we investigated the role of the autophagy-related protein Atg11 in 〈em〉C. albicans〈/em〉. Deletion of 〈em〉ATG11〈/em〉 led to the defect in growth under the nitrogen starvation condition. Western blotting and GFP localization further revealed that the transport and degradation of Atg8 was blocked in the 〈em〉atg11〈/em〉Δ/Δ mutant under both the nitrogen starvation and hypha-inducing conditions. Moreover, degradation of both Lap41 (the indicator of the cytoplasm-to-vacuole pathway) and Csp37 (the indicator of mitophagy) was also thoroughly suppressed in this mutant under nitrogen starvation. These results indicated that Atg11 plays an essential role in both non-selective and selective autophagy in 〈em〉C. albicans〈/em〉.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 3 September 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Biochemical and Biophysical Research Communications, Volume 516, Issue 4〈/p〉 〈p〉Author(s): Yi-meng Cao, Meng-yu Liu, Zhuo-wei Xue, Yu Qiu, Jie Li, Yang Wang, Qing-kai Wu〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Promotion of wound healing is one of the most important fields in clinical medical research. This study aimed to evaluate the potential use of a new surface-structured bacterial cellulose(S-BC) biomaterial with human urine-derived stem cells (hUSCs) for wound healing. In vitro, EA.hy926 were inoculated on structured/non-structured bacterial cellulose, and the growth of EA.hy926 on bacterial cellulose in medium with/without conditioned medium of the hUSCs were observed to explore the effect of bacterial cellulose's surface structure and hUSCs-CM on vascular endothelial cell growth. In vivo, we covered wound surface with various BC materials and/or injected the hUSCs into the wound site on group BC, group S-BC, group hUSCs, group BC + hUSCs, group S-BC + hUSCs to evaluate the effect of S-BC and hUSCs on wound healing in rat full-thickness skin defect model. In vitro study, surface structure of S-BC could promote the growth and survival of EA.hy926, and the hUSCs-CM could further promote the proliferation of EA.hy926 on S-BC. In vivo study, wound healing rate of the group BC, group S-BC, group hUSCs was significantly accelerated, accompanied by faster re-epithelialization, collagen production and neovascularization than control group. It is note worthy that the effect of S-BC on wound healing was better than BC, the effect of S-BC + hUSCs on wound healing was better than BC + hUSCs. Moreover, the effect of S-BC combined with hUSCs on wound is better than treated with S-BC or hUSCs alone. All the findings suggest that the combination of S-BC and hUSCs could facilitate skin wound healing by promoting angiogenesis. This combination of the role of stem cells and biomaterial surface structures may provide a new way to address clinical wound healing problems.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 3 September 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Biochemical and Biophysical Research Communications, Volume 516, Issue 4〈/p〉 〈p〉Author(s): Naohiro Katagiri, Satoru Nagatoishi, Kouhei Tsumoto, Hideya Endo〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Methionine aminopeptidase 2 (MetAP2) is one of the effector proteins of S100A4, a metastasis-associated calcium-binding protein. This interaction is involved in angiogenesis. The region of MetAP2 that interacts with S100A4 includes amino acids 170 to 208. A peptide corresponding to this region, named as NBD, has potent anti-angiogenic activity and suppresses tumor growth in a xenograft cancer model. However, the binding mode of NBD to S100A4 was totally unknown. Here we describe our analysis of the relationship between the inhibitory activity and the structure of NBD, which adopts a characteristic helix-turn-helix structure as shown by X-ray crystallographic analysis, and peptide fragments of NBD. We conducted physicochemical analyses of the interaction between S100A4 and the peptides, including surface plasmon resonance, microscale thermophoresis, and circular dichroism, and performed docking/molecular dynamics simulations. Active peptides had stable secondary structures, whereas inactive peptides had a little secondary structure. A computational analysis of the interaction mechanism led to the design of a peptide smaller than NBD, NBD-ΔN10, that possessed inhibitory activity. Our study provides a strategy for design for a specific peptide inhibitor against S100A4 that can be applied to the discovery of inhibitors of other protein-protein interactions.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 1 September 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Biochimica et Biophysica Acta (BBA) - Biomembranes, Volume 1861, Issue 9〈/p〉 〈p〉Author(s): Anargyros Doukas, Ekaterini Karena, Maria Botou, Konstantinos Papakostas, Amalia Papadaki, Olympia Tziouvara, Evaggelia Xingi, Stathis Frillingos, Haralabia Boleti〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Recombinant expression systems for mammalian membrane transport proteins are often limited by insufficient yields to support structural studies, inadequate post-translational processing and problems related with improper membrane targeting or cytotoxicity. Use of alternative expression systems and optimization of expression/purification protocols are constantly needed. In this work, we explore the applicability of the laboratory strain LEXSY of the ancient eukaryotic microorganism 〈em〉Leishmania tarentolae〈/em〉 as a new expression system for mammalian nucleobase permeases of the NAT/NCS2 (Nucleobase-Ascorbate Transporter/Nucleobase-Cation Symporter-2) family. We achieved the heterologous expression of the purine-pyrimidine permease rSNBT1 from 〈em〉Rattus norvegicus〈/em〉 (tagged at C-terminus with a red fluorescent protein), as confirmed by confocal microscopy and biochemical analysis of the subcellular fractions enriched in membrane proteins. The cDNA of rSNBT1 has been subcloned in a pLEXSY-〈em〉sat-mrfp1〈/em〉vector and used to generate transgenic 〈em〉L〈/em〉. 〈em〉tarentolae-rsnbt1-mrfp1〈/em〉 strains carrying the pLEXSY-sat-〈em〉rsnbt1-mrfp1〈/em〉 plasmid either episomally or integrated in the chromosomal DNA. The chimeric transporter rSNBT1-mRFP1 is targeted to the ER and the plasma membrane of the 〈em〉L〈/em〉. 〈em〉tarentolae〈/em〉 promastigotes. The transgenic strains are capable of transporting nucleobases that are substrates of rSNBT1 but also of the endogenous 〈em〉L〈/em〉. 〈em〉tarentolae〈/em〉 nucleoside/nucleobase transporters. A dipyridamole-resistant Na〈sup〉+〈/sup〉-dependent fraction of uptake is attributed to the exogenously expressed rSNBT1.〈/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-S0005273619301452-ga1.jpg" width="500" alt="Unlabelled Image" title="Unlabelled Image"〉〈/figure〉〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 3 September 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Biochemical and Biophysical Research Communications, Volume 516, Issue 4〈/p〉 〈p〉Author(s): Xue Mei Li, Soo Jung Kim, Dong-Kyun Hong, Kyoung Eun Jung, Chong Won Choi, Young-Joon Seo, Jeung-Hoon Lee, Young Lee, Chang-Deok Kim〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Kruppel-like factor 4 (KLF4) is a zinc-finger transcription factor that plays a role in terminal differentiation of epidermal keratinocytes. There are conflicting reports regarding the role of KLF4 in tumor development, with both the tumor suppressive and/or oncogenic properties depending on different conditions and cell types. In this study, we investigated the functional importance of KLF4 in cutaneous squamous cell carcinoma (SCC). Immunohistochemistry showed that KLF4 expression was relatively low in SCC lesion compared to normal epidermis. To examine the effects of KFL4, we transduced SCC lines (SCC12 and SCC13 cells) with the KLF4-expressing recombinant adenovirus. Overexpression of KLF4 significantly decreased cell proliferation and colony forming activity. In addition, overexpression of KLF4 markedly reduced invasive potential, along with the downregulation of epithelial-mesenchymal transition (EMT)-related molecules. In a mechanistic study, KLF4 inhibited SOX2, of which expression is critical for tumor initiation and growth of SCC. Further investigations indicated that SOX2 expression is induced by TGF-β/SMAD signaling, and that overexpression of KLF4 inhibited SMAD signaling via upregulation of SMAD7, an important inhibitory SMAD molecule. Based on these data, KLF4 plays a tumor suppressive role in cutaneous SCC cells.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 3 September 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Biochemical and Biophysical Research Communications, Volume 516, Issue 4〈/p〉 〈p〉Author(s): Yan Shen, Shengnan Chen, Yan Zhao〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Hyperglycemia-induced podocyte injury plays a vital role in the development of diabetic nephropathy. Sulfiredoxin-1 (Srxn1) is emerging as a cytoprotective protein that protects from various insults in a wide range of cell types. However, whether Srxn1 is involved in regulating hyperglycemia-induced podocyte injury and participates in diabetic nephropathy remains unknown. In the present study, we aimed to explore the potential role of Srxn1 in regulating high glucose (HG)-induced apoptosis and oxidative stress of podocytes 〈em〉in vitro〈/em〉. Results demonstrated that Srxn1 was induced in HG-stimulated podocytes. The depletion of Srxn1 by Srxn1 siRNA-mediated gene silencing significantly exacerbated HG-induced apoptosis and the production of reactive oxygen species (ROS), while Srxn1 overexpression attenuated HG-induced apoptosis and ROS production. In-depth molecular mechanism research revealed that Srxn1 overexpression promoted the nuclear expression of nuclear factor (erythroid-derived 2)-like 2 (Nrf2) and reinforced antioxidant response element (ARE)-mediated transcription activity. Moreover, results confirmed that Srxn1 increased the activation of Nrf2/ARE signaling associated with inactivating glycogen synthase kinase (GSK)-3β. Notably, the inhibition of GSK-3β significantly reversed Srxn1 silencing-induced adverse effects in HG-treated cells, while the knockdown of Nrf2 abrogated the Srxn1-mediated protective effect against HG-induced podocyte injury. Taken together, our results demonstrated that Srxn1 protects podocytes from HG-induced injury by promoting the activation of Nrf2/ARE signaling associated with inactivating GSK-3β, indicating a potential role of Srxn1 in diabetic nephropathy. Our study suggests that Srxn1 may serve as a potential target for kidney protection.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0006291X19313178-fx1.jpg" width="398" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 15 October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Analytical Biochemistry, Volume 583〈/p〉 〈p〉Author(s): Satoru Adachi, Hidetoshi Aoki, Yumi Ueda, Tetsuo Sudo, Ai Nozawa, Shigetaka Koga, Hisashi Suzuki, Sachie Shibayama, Naohiro Noda, Shin-ichiro Fujii, Sayaka Itoh, Sayaka Kawashima, Yoshihiko Suda, Hiroki Nakae〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The performance indicator called limit of detection for microarray platform (LODP) was defined in ISO 16578:2013. The methods to determine practical LODP were explored. In general, + 3 SD of the background is used as the signal strength of limit of detection and criteria for dividing positive and negative results. Since the negative signal had been defined differently for each microarray platform, signals obtained from Non-Probe Spots (NPS) installed on the microarrays were defined as the “background” of microarrays. LODP was determined as the lowest concentration of which the average signal exceeded Avg. + 3 SD of the background (NPS) and the signal was significantly different from those of the lower and higher adjacent concentration points measured with a diluted series of reference materials. For reliable qualitative analysis, the positive results can be defined as signals higher than those corresponding to LODP and negative results as lower signals, without determining limit of detection for all target probes. The use of LODP also enables comparisons of platform performances without checking sequence dependencies, and assists to select reliable and fitting platforms for experimental purposes.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Biochemical Pharmacology, Volume 168〈/p〉 〈p〉Author(s): Daniel Lavall, Nadine Jacobs, Felix Mahfoud, Peter Kolkhof, Michael Böhm, Ulrich Laufs〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Mineralocorticoid receptor (MR) overactivation promotes cardiac fibrosis. We studied the ability of the non-steroidal MR antagonist finerenone to prevent fibrotic remodeling. In neonatal rat cardiac fibroblasts, finerenone prevented aldosterone-induced nuclear MR translocation. Treatment with finerenone decreased the expression of connective tissue growth factor (CTGF) (74 ± 15% of control, p = 0.005) and prevented aldosterone-induced upregulation of CTGF and lysyl oxidase (LOX) completely. Finerenone attenuated the upregulation of transforming growth factor ß (TGF-ß), which was induced by the Rac1 GTPase activator 〈span〉l〈/span〉-buthionine sulfoximine. Transgenic mice with cardiac-specific overexpression of Rac1 (RacET) showed increased left ventricular (LV) end-diastolic (63.7 ± 8.0 vs. 93.8 ± 25.6 µl, p = 0.027) and end-systolic (28.0 ± 4.0 vs. 49.5 ± 16.7 µl, p = 0.014) volumes compared to wild-type FVBN control mice. Treatment of RacET mice with 100 ppm finerenone over 5 months prevented LV dilatation. Systolic and diastolic LV function did not differ between the three groups. RacET mice exhibited overactivation of MR and 11ß hydroxysteroid dehydrogenase type 2. Both effects were reduced by finerenone (reduction about 36%, p = 0.030, and 40%, p = 0.032, respectively). RacET mice demonstrated overexpression of TGF-ß, CTGF, LOX, osteopontin as well as collagen and myocardial fibrosis in the left ventricle. In contrast, expression of these parameters did not differ between finerenone-treated RacET and control mice. Finerenone prevented left atrial dilatation (6.4 ± 1.5 vs. 4.7 ± 1.4 mg, p = 0.004) and left atrial fibrosis (17.8 ± 3.1 vs. 12.8 ± 3.1%, p = 0.046) compared to vehicle-treated RacET mice. In summary, finerenone prevented from MR-mediated structural remodeling in cardiac fibroblasts and in RacET mice. These data demonstrate anti-fibrotic myocardial effects of finerenone.〈/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-S0006295219302564-ga1.jpg" width="500" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 3 September 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Biochemical and Biophysical Research Communications, Volume 516, Issue 4〈/p〉 〈p〉Author(s): Yu-Lun Huang, Gota Kawai, Atsuhiko Hasegawa, Mari Kannagi, Takao Masuda〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Reverse transcription of retroviral RNA is accomplished through a minus-strand strong stop cDNA (-sscDNA) synthesis and subsequent strand-transfer reactions. We have previously reported a critical role of guanosine (G) number at 5′-terminal of HIV-1 RNA for successful strand-transfer of -sscDNA. In this study, role(s) of the cap consisting of 7-methyl guanosine (〈sup〉7m〈/sup〉G), a hallmark of transcripts generated by RNA polymerase II, at the 5′-end G nucleotide (5′-G) of HIV-1 RNA were examined. In parallel, contribution of highly conserved GGG tract located at the U3/R boundary in 3′ terminal region of viral RNA (3′-GGG tract) was also addressed. The in vitro reverse transcription analysis using synthetic HIV-1 RNAs possessing the 5′-G with cap or triphosphate form demonstrated that the 5′-cap significantly increased strand-transfer efficiency of -sscDNA. Meanwhile, effect of the 5′-cap on the strand-transfer was retained in the reaction using mutant HIV-1 RNAs in which two Gs were deleted from the 3′-GGG tract. Lack of apparent contribution of the 3′-GGG tract during strand-transfer events in vitro was reproduced in the context of HIV-1 replication within cells. Instead, we noticed that the 3′-GGG tract might be required for efficient gene expression from proviral DNA. These results indicated that 〈sup〉7m〈/sup〉G of the cap on HIV-1 RNA might not be reverse-transcribed and a possible role of the 3′-GGG tract to accept the non-template nucleotide addition during -sscDNA synthesis might be less likely. The 5′-G modifications of HIV-1 RNAs by the cap- or phosphate-removal enzyme revealed that the cap or monophosphate form of the 5′-G was preferred for the 1st strand-transfer compared to the triphosphate or non-phosphate form. Taken together, a status of the 5′-G determined strand-transfer efficiency of -sscDNA without affecting the non-template nucleotide addition, probably by affecting association of the 5′-G with 3′-end region of viral RNA.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0006291X19312926-fx1.jpg" width="307" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: Available online 5 July 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Space Policy〈/p〉 〈p〉Author(s): Bergit Uhran, Catharine Conley, J. Andy Spry〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Planetary protection, or the protection of celestial bodies from potentially harmful contamination, has been required by international law since the ratification of the Treaty on Principles Governing the Activities of States in the Exploration and Use of Outer Space in 1967. At that time, scientists were concerned about the potential of contaminating the Moon or bringing back a life form of lunar origin when astronauts returned to Earth with samples. The evidence is that the Moon does not contain indigenous life, but other celestial bodies may. Mars is of particular concern because of its habitability and plans to carry out a robotic sample return mission and even potentially human crewed missions in the near future (next 20–30 years). This article (recognizing that other national and international tasks are ongoing with detailed studies of technical aspects of containment and sample analysis) provides an overview of the policy aspects of planetary protection and sample return, discussing the history of planetary protection, lessons learned from the Apollo missions, and a potential strategy to ensure prevention contamination if a robotic sample return mission is carried out. It is recommended that the capability performed in the 1960s by the Interagency Committee on Back Contamination be reestablished, that regulations be developed to allow quarantine of anyone exposed to the samples, that scientific and technical personnel be trained in a receiving laboratory for at least 2 years prior to sample return, and that a test protocol be established for examining the samples. This will protect our biosphere while enabling groundbreaking research into conditions on Mars and any possible signs of life.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: Available online 5 July 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Space Policy〈/p〉 〈p〉Author(s): Harald Köpping Athanasopoulos〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉This article discusses the Moon Village concept within the context of the increasing momentum to return human beings to the surface of the Moon. The article follows a dual objective. Firstly, the Moon Village is probably the most misunderstood among the plethora of ideas to explore the Moon scientifically and commercially. The article is therefore intended to explore what the Moon Village actually is. Secondly, the article explores the strengths and weaknesses of the Moon Village. The article is divided into three sections. The first section reviews the current Moon projects of public and private space actors, including the United States, Russia, China, SpaceX and Blue Origin. It sets the scene for the argument that the Moon Village has entered global discourse on space within a positive political environment. The second section discusses the premises of ESA chief Jan Wörner’s Moon Village concept, putting forward that the Moon Village is intended as an open concept rather than as a concrete plan. It is a process rather than a project and it is meant to initiate a global conversation on humanity’s future on the Moon. As such, the world café is an appropriate metaphor to illustrate the idea behind the Moon Village. In the third and final section a SWAT/PEST analysis is conducted to assess the feasibility of the Moon Village, highlighting that one of the major opportunities of the project is to promote international cooperation. The article concludes by supporting the institutionalist hypothesis that the Moon Village is arguably a translation of the ESA system to the global level, as participation is voluntary and as it builds on the strengths of each cooperation partner. As such, the Moon Village in indeed a new way of doing space on the global level.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 International Journal of Heat and Mass Transfer, Volume 141〈/p〉 〈p〉Author(s): D.Y. Yeo, H.C. NO〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉In this paper, two-phase drag models for a packed bed of uniform-size particles were suggested, and they were applied to the calculation of pressure drop and dryout heat flux. We provided physical basis for the two-phase flow regime model through the analysis of the interfacial friction (〈em〉F〈sub〉i〈/sub〉〈/em〉). The suggested model provides flow patterns representing bubbly, slug, and channel flow and considering three criteria including d〈sup〉2〈/sup〉〈em〉F〈sub〉i〈/sub〉〈/em〉/d〈em〉α〈/em〉〈sup〉2〈/sup〉 = 0, 〈em〉F〈sub〉i〈/sub〉〈/em〉 = maximum, and 〈em〉F〈sub〉i〈/sub〉〈/em〉 = 0. The results obtained from the three criteria were drawn with several observation-based experimental ones to generate the flow regime map (void fraction vs. particle diameter). Through the current flow regime map, we clearly saw the existence of channel flow in a packed bed with particles smaller than around 3.5 mm. Then, mechanistic interfacial friction models were developed on basis of the current two-phase flow map of bubbly flow, slug flow, channel flow and annular flow. The suggested interfacial friction models were validated with top- and bottom-flooding air-water experiments and boiling experiments. We found out that the capability of pressure drop estimation by the current model were significantly improved for a bed with small particles. Finally, a zero-dimensional dryout heat flux (DHF) model was derived using the suggested interfacial friction models, and validated against DHF experimental data for beds with 1-D configuration. The root-mean-square error (RMSE) of the suggested DHF model was 35%, which was the smallest among the RMSEs of the previous DHF models.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Fluids and Structures, Volume 90〈/p〉 〈p〉Author(s): Julien Cisonni, Anthony D. Lucey, Novak S.J. Elliott〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Flutter instability of flexible cantilevers axially immersed in channel flow has been studied mainly for slender bodies with uniform properties. The present study addresses the stability of one-dimensional stepped cantilevers comprising two sections of different thickness immersed in two-dimensional viscous channel flow. The influence of the relative mass and rigidity of the two sections on the motion of the cantilever is explored through variations of length and thickness ratios. The parametric investigation shows that, for instance, making the free end of the cantilever twice thinner or thicker than the clamped end over a short fraction can produce structures that are either more stable or more unstable, depending on the fluid-to-solid mass ratio. In the case of a heavy and stiff free section and a light and flexible clamped section of comparable length, the excitation of lower structural modes by slower flows is significantly destabilising as compared to a uniform cantilever of same length and total mass. Strong destabilisation and weak stabilisation of the fluid–structure interaction system can result from either thinning or thickening the cantilever free-end which can also lead to changes in the flutter mode shape. These complex variations are quantitatively presented through stability maps.〈/p〉〈/div〉

Description: 〈p〉Publication date: October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 International Journal of Heat and Mass Transfer, Volume 141〈/p〉 〈p〉Author(s): Tianyu Ma, Lei Feng, Hu Wang, Haifeng Liu, Mingfa Yao〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Spray impingement has aroused more and more interests in recent years with the increase of injection pressure in internal combustion engines. In this paper, the near wall combustion after fuel spray impingement is studied based on an updated film development model and experiment in constant volume vessel. Relationship between spray injection and flame development under different ambient temperature is analyzed as well as the near wall distribution of combustion products. In the first part, a mathematical model that considered the effects of surface tension on spray impingement is built for better prediction of film development. Reasonable results are obtained at room temperature spray impingement case, and the split distribution of film depth is also well captured. In the second part, flame development in the near wall region is investigated based on the proposed numerical model and experiments. The result shows that the flame becomes circumferentially nonuniformed at lower ambient temperature (723 K) and the evolution of downstream flame become sensitive to the wall temperature. At lower ambient temperature (723 K), increasing wall temperature could enlarge the high temperature zone, which is helpful to accelerate the film evaporation and soot oxidation. At higher ambient temperature condition, the spray impact angle should be reduced to create more concentrated combustion (stronger stratification), which could improve the combustion efficiency in the near wall region.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: Available online 5 July 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Progress in Aerospace Sciences〈/p〉 〈p〉Author(s): Dantong Ge, Pingyuan Cui, Shengying Zhu〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉As small celestial body exploration advances, higher requirements with regard to system safety and landing precision are proposed for future landing and sample return missions. However, due to limited prior information about the target, the complex dynamics environment, and significant time-delay, performing a descent and landing on the small body surface is challenging. Among all the techniques required for achieving a safe landing, onboard guidance, navigation, and control (GNC) is of paramount importance in determining mission success. In this paper, a systematic survey of the autonomous GNC technologies for descent and landing on small bodies is carried out. First, based on an analysis of the technical challenges in the process, an overview of typical small body landing and sample return missions is given. Then, an elaboration of the state-of-the-art GNC technologies is presented. Specifically, autonomous navigation methods in unknown environments with highly-nonlinear dynamics are introduced. Descent guidance and control algorithms that take into account landing performance optimization and system robustness against model uncertainties are discussed. Touchdown dynamics and control methods proposed for precise and safe surface contact under weak gravity are analyzed. And safe strategies for onboard detected emergencies such as collision threats and system malfunctions are explained. Besides the prevalent methods, innovative techniques with respect to observability-based optimization, edge curve matching, online landing site selection, collision probability-based hazard avoidance, and trajectory curvature guidance proposed for improving system safety and landing performance are elucidated. At last, based on the growing system autonomy and operational complexity demands, a prospect of future research directions for small body GNC technologies is given.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 1 October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Chemical Physics, Volume 526〈/p〉 〈p〉Author(s): Min You, Haoran Fan, Yang Wang, Wenkai Zhang〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Tryptophan derivatives have long been used as site-specific fluorescent probes. 4-cyanotryptophan emits in the visible region and is the smallest blue fluorescent amino acid probe. We performed UV–Vis, steady-state and time-resolved fluorescence spectroscopy on six aldehyde-derivatized indoles dissolved in water and found that indole-4-carboxaldehyde (I4A) has the largest redshifts among all reported indole derivatives and can emit in the green region of the visible spectrum, which suggests that substitution of the indole ring of Trp using I4A may make a green fluorescent amino acid probe. It differs from tryptophan by only 3 atoms and will be the smallest green fluorescent amino acid probe that has great potential to be used in spectroscopic and microscopic measurements of proteins. We also found that I4A could be used as a fluorescent probe to detect trace water in organic solvents since its maximum emission wavelength is extremely sensitive to local hydrogen-bonding status.〈/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-S0301010419305956-ga1.jpg" width="500" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 3 September 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Biochemical and Biophysical Research Communications, Volume 516, Issue 4〈/p〉 〈p〉Author(s): Xiong Wang, Huishou Zhao, Wenjun Yan, Yi Liu, Tao Yin, Shan Wang, Miaomiao Fan, Congye Li, Ling Zhang, Ling Tao〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Atherosclerosis is characterized by the accumulation of excess cholesterol in plaques. Reverse cholesterol transport (RCT) plays a key role in the removal of cholesterol. In the present study, we examined the effect of thioredoxin-1 (Trx-1) on RCT and explored the underlying mechanism. We found that Trx-1 promoted RCT 〈em〉in vivo〈/em〉, as did T0901317, a known liver X receptor (LXR) ligand. T0901317 also inhibited the development of atherosclerotic plaques but promoted liver steatosis. Furthermore, Trx-1 promoted macrophage cholesterol efflux to apoAI 〈em〉in vitro〈/em〉. Mechanistically, Trx-1 promoted nuclear translocation of LXRα and induced the expression of ATP-binding cassette transporter A1 (ABCA1). Apolipoprotein E knockout (apoE−/−) mice fed an atherogenic diet were daily injected intraperitoneally with saline or Trx-1 (0.33 mg/kg). Trx-1 treatment significantly inhibited the development of atherosclerosis and induced the expression of ABCA1 in macrophages retrieved from apoE−/− mice. Moreover, the liver steatosis was attenuated by Trx-1. Overall, we demonstrated that Trx-1 promotes RCT by upregulating ABCA1 expression through induction of nuclear translocation of LXRα, and protects liver from steatosis.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 13 August 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Biochemical and Biophysical Research Communications, Volume 516, Issue 1〈/p〉 〈p〉Author(s): 〈/p〉

Description: 〈p〉Publication date: 3 September 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Biochemical and Biophysical Research Communications, Volume 516, Issue 4〈/p〉 〈p〉Author(s): Azuma Kosai, Nanao Horike, Yoshiaki Takei, Akihiro Yamashita, Kaori Fujita, Takashi Kamatani, Noriyuki Tsumaki〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The maturation of chondrocytes is strictly regulated for proper endochondral bone formation. Although recent studies have revealed that intracellular metabolic processes regulate the proliferation and differentiation of cells, little is known about how changes in metabolite levels regulate chondrocyte maturation. To identify the metabolites which regulate chondrocyte maturation, we performed a metabolome analysis on chondrocytes of Sik3 knockout mice, in which chondrocyte maturation is delayed. Among the metabolites, acetyl-CoA was decreased in this model. Immunohistochemical analysis of the Sik3 knockout chondrocytes indicated that the expression levels of phospho-pyruvate dehydrogenase (phospho-Pdh), an inactivated form of Pdh, which is an enzyme that converts pyruvate to acetyl-CoA, and of Pdh kinase 4 (Pdk4), which phosphorylates Pdh, were increased. Inhibition of Pdh by treatment with CPI613 delayed chondrocyte maturation in metatarsal primordial cartilage in organ culture. These results collectively suggest that decreasing the acetyl-CoA level is a cause and not result of the delayed chondrocyte maturation. Sik3 appears to increase the acetyl-CoA level by decreasing the expression level of Pdk4. Blocking ATP synthesis in the TCA cycle by treatment with rotenone also delayed chondrocyte maturation in metatarsal primordial cartilage in organ culture, suggesting the possibility that depriving acetyl-CoA as a substrate for the TCA cycle is responsible for the delayed maturation. Our finding of acetyl-CoA as a regulator of chondrocyte maturation could contribute to understanding the regulatory mechanisms controlling endochondral bone formation by metabolites.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 3 September 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Biochemical and Biophysical Research Communications, Volume 516, Issue 4〈/p〉 〈p〉Author(s): Saujanya Acharya, Shubhankar Dutta, Sucheta Chopra, Kakoli Bose〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Human HtrA3 (High temperature requirement protease A3) is a trimeric PDZ bearing propapoptotic serine protease, which is involved in various diseases including cancer and pre-eclampsia. Proposed to be a tumor suppressor, its role as a potential therapeutic target is strongly advocated. Therefore, it becomes imperative to gain insights into its mechanism of action and regulation. Allostery is a well-known mechanism of catalytic activation for many HtrA3 homologs, which opens up avenues for manipulating enzyme functions for therapeutic intervention. In our study, through 〈em〉in silico〈/em〉 and biochemical approaches, we have reported for the first time that HtrA3 shows allosteric behaviour. We identified a novel selective binding pocket, which triggers conformational reorientations through signal propagation to the distantly situated active-site pocket via the functionally important loop regions. Using molecular docking, simulation studies and biochemical studies we have identified the regulatory movements at and around the active site pocket. Our study is the first one to report a non-classical binding site for HtrA3, which is instrumental for formation of a catalytically efficient orthosteric pocket upon substrate binding.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0006291X19313312-fx1.jpg" width="470" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 3 September 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Biochemical and Biophysical Research Communications, Volume 516, Issue 4〈/p〉 〈p〉Author(s): Farnoush Asghari-Paskiabi, Mohammad Imani, Hashem Rafii-Tabar, Mehdi Razzaghi-Abyaneh〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Selenium sulfide is a well-known bioactive chemical whose biosynthesis as a nanoparticle (NP) is a controversial issue. In the present study, we employed 〈em〉Saccharomyces cerevisiae〈/em〉 to generate a novel synthetic process of selenium sulfide NPs. The addition of selenium/sulfur precursors to 〈em〉S. cerevisiae〈/em〉 culture produced NPs, which we isolated and characterized the physicochemical properties, toxicity, and antifungal activity. Transmission electron microscopy indicated the presence of the NPs inside the cells. Selenium sulfide NPs were successfully synthesized with average size of 6.0 and 153 nm with scanning electron micrographs and 360 and 289 nm in Zeta sizer using different precursors. The presence of sulfur/selenium in the particles was confirmed by energy-dispersive X-ray spectroscopy and elemental mapping. Fourier-transform infrared spectroscopy supported the production of selenium sulfide NPs. X-ray diffractograms showed the presence of characteristic peaks of selenium sulfide NPs which were further confirmed by mass spectrometry. The obtained NPs strongly inhibited the growth of pathogenic fungi that belonged to the genera 〈em〉Aspergillus〈/em〉, 〈em〉Candida〈/em〉, 〈em〉Alternaria〈/em〉 and the dermatophytes, while no cytotoxicity was observed in MTT assay. In conclusion, efficient green synthesis of selenium sulfide NPs with appropriate physicochemical properties is possible in bio-systems like 〈em〉S. cerevisiae〈/em〉.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0006291X19313361-fx1.jpg" width="285" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 3 September 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Biochemical and Biophysical Research Communications, Volume 516, Issue 4〈/p〉 〈p〉Author(s): Masashi Maekawa, Hiromi Hiyoshi, Jun Nakayama, Kohki Kido, Tatsuya Sawasaki, Kentaro Semba, Eiji Kubota, Takashi Joh, Shigeki Higashiyama〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Eukaryotic translation initiation factor 3 subunit D (EIF3D) binds to the 5′-cap of specific mRNAs, initiating their translation into polypeptides. From a pathological standpoint, EIF3D has been observed to be essential for cell growth in various cancer types, and cancer patients with high EIF3D mRNA levels exhibit poor prognosis, indicating involvement of EIF3D in oncogenesis. In this study, we found, by mass spectrometry, that Cullin-3 (CUL3)/KCTD10 ubiquitin (Ub) ligase forms a complex with EIF3D. We also demonstrated that EIF3D is K27-polyubiquitinated at the lysine 153 and 275 residues in a KCTD10-dependent manner in human hepatocellular carcinoma HepG2 cells. Similar to other cancers, high expression of EIF3D significantly correlated with poor prognosis in hepatocellular carcinoma patients, and depletion of EIF3D drastically suppressed HepG2 cell proliferation. These results indicate that EIF3D is a novel substrate of CUL3/KCTD10 Ub ligase and suggest involvement of K27-polyubiquitinated EIF3D in the development of hepatocellular carcinoma.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 1 October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Computer Methods in Applied Mechanics and Engineering, Volume 355〈/p〉 〈p〉Author(s): Zhao Wang, Amit Subhash Shedbale, Sachin Kumar, Leong Hien Poh〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉A localizing gradient damage model with micro inertia effect is proposed for the dynamic fracture of quasi-brittle materials. The objective is to achieve mesh independent solutions, and to avoid spurious effects associated with the conventional nonlocal enhancement. The proposed localizing gradient damage model closely resembles the conventional gradient enhancement, albeit with an interaction domain that decreases with damage, complemented by a micro inertia effect. We first consider a classical crack branching problem, where the localizing gradient damage model is shown to resolve the mesh sensitivity issue, as well as to correctly reproduce the crack profile. Moreover, the micro inertia effect is observed to retard the crack velocity. Next, the tensile loading of a Polymethyl Methacrylate plate is considered. It is shown that the proposed model effectively captures the experimentally observed transition of crack profiles as the loading rate increases, i.e. from a straight crack propagation, to sub-branching, and finally to macro branching. Numerical results in terms of crack patterns, crack velocities, and fracture energies are in good agreement with the experimental data. To furthermore demonstrate the superior performance of the localizing gradient damage model, the macro branching problem is solved using the conventional gradient enhancement with micro inertia. It is shown that a spurious damage growth and an erroneous interaction between closely spaced cracks suppress the development of macro branching, even though reasonable values are obtained for the fracture energy and crack velocity. The localizing gradient damage model is able to fully resolve these issues.〈/p〉〈/div〉

Description: 〈p〉Publication date: 1 October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Computer Methods in Applied Mechanics and Engineering, Volume 355〈/p〉 〈p〉Author(s): D. Xiao〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉A novel error estimation method for the parametric non-intrusive reduced order model (P-NIROM) based on machine learning is presented. This method relies on constructing a set of response functions for the errors between the high fidelity full model solutions and P-NIROM using machine learning method, particularly, Gaussian process regression method. This yields closer solutions agreement with the high fidelity full model. The novelty of this work is that it is the first time to use machine learning method to derive error estimate for the P-NIROM. The capability of the new error estimation method is demonstrated using three numerical simulation examples: flow past a cylinder, dam break and 3D fluvial channel. It is shown that the results are closer to those of the high fidelity full model when considering error terms. In addition, the interface between two phases of dam break case is captured well if the error estimator is involved in the P-NIROM.〈/p〉〈/div〉

Description: 〈p〉Publication date: 1 October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Computer Methods in Applied Mechanics and Engineering, Volume 355〈/p〉 〈p〉Author(s): M. Goudarzi, A. Simone〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉We report the results of a comparative analysis of mesh independent discrete inclusion models and point out some shortcomings of classical approaches in the approximation of the strain field across an inclusion (artificial continuity) and the slip profile along an inclusion (oscillatory behavior). We also present novel embedded reinforcement models based on partition of unity enrichment strategies, adaptive 〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline" altimg="si246.svg"〉〈mi〉h〈/mi〉〈/math〉-refinement, and order/regularity extensions. These novel models are assessed by means of mesh convergence studies and it is shown that they improve the quality of the solution by significantly decreasing local spurious oscillations in the slip profile along an inclusion.〈/p〉〈/div〉

Description: 〈p〉Publication date: 1 October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Computer Methods in Applied Mechanics and Engineering, Volume 355〈/p〉 〈p〉Author(s): C. Hermange, G. Oger, Y. Le Chenadec, D. Le Touzé〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉A 3D fluid–structure coupling between Smoothed Particle Hydrodynamics (SPH) and Finite Element (FE) methods is proposed in this paper, with its application to complex tire hydroplaning simulations on rough ground. The purpose of this work is to analyze the SPH–FE coupling capabilities for modeling efficiently such a complex phenomenon. On the fluid side, the SPH method is able to handle the three complex interfaces of the hydroplaning phenomenon: free-surface, ground/fluid and fluid/tire interfaces. On the solid side, the FE method is used for its ability to treat tire–ground contact. A new algorithm dedicated to such SPH–FE coupling strategies is proposed to optimize the computational efficiency through the use of differed time steps between fluid and solid solvers. This way, the number of calls to the FE solver is minimized while maintaining the accuracy and stability of the coupling. The ratio between these respective time steps relies on a control procedure based on pressure loading. The present 3D SPH–FE model is first validated with different academic test cases and experimental data before considering the complex problem of the 3D hydroplaning simulations. Hydroplaning simulations are performed and analyzed on 3D configurations involving both smooth and rough grounds.〈/p〉〈/div〉

Description: 〈p〉Publication date: 16 August 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Tetrahedron, Volume 75, Issue 33〈/p〉 〈p〉Author(s): Chuang Zhao, Gao-Feng Zha, Wan-Yin Fang, Njud S. Alharbi, Hua-Li Qin〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉A simple, practical and gram-scale process for direct transformation of primary alcohols or silyl ethers to ammonium salts was developed. This method has the feathers of easy work-up (a simple filtration), mild condition, high yield, great practicality and robustness. And the application of the ammonium salts in Suzuki coupling reaction was also accomplished.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0040402019307495-fx1.jpg" width="500" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 13 October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Sound and Vibration, Volume 458〈/p〉 〈p〉Author(s): Xiao-Dong Yang, Zhen-Kun Guo, Wei Zhang, Yuan Ren, Melnik V.N. Roderick〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Although the substitution idea has been used occasionally in some engineering structures to study vibration characteristics, it is still short of systematic study in the vibrational engineering field. We summarize the techniques of the substitution method in this paper and apply such skill further to continuous and nonlinear systems, by which the dimension of the system can be reduced. By illustrated examples of frequency analysis on Timoshenko beam and composite sandwich structure, the substitution method has verified to be valid and efficient. The gyroscopic systems, represented by both rotating structures and orbits around libration points have also been presented to show the power of substitution method. Illustrated by the current examples, it is concluded that the substitution method has wide potential applications via studying the functional relations among all the degree-of-freedoms (DOFs) of non-gyroscopic or gyroscopic systems.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 15 October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Colloid and Interface Science, Volume 554〈/p〉 〈p〉Author(s): Xiaofei Wang, Yifu Zhang, Jiqi Zheng, Xin Liu, Changgong Meng〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Vanadium sulfide (VS〈sub〉4〈/sub〉) is recognized as a good anode material for energy storage devices because of its chain-like structure and high content of sulfur. Herein, the patronite VS〈sub〉4〈/sub〉 anchored on carbon nanocubes (denoted as VS〈sub〉4〈/sub〉/CNTs) with a petal-shape structure consisting of nanolayers is successfully prepared through a one-step hydrothermal reaction. The influence of the optimal ratio of VS〈sub〉4〈/sub〉 and CNTs on the electrochemical properties of VS〈sub〉4〈/sub〉/CNTs composite is studied by cyclic voltammetry (CV), galvanostatic charge-discharge (GCD) and electrochemical impedance spectroscopy (EIS). The addition of CNTs increases the conductivity and relieves the volume expansion/contraction, resulting excellent electrochemical properties of VS〈sub〉4〈/sub〉/CNTs. In the potential window of −1.4 V to 1.4 V, the VS〈sub〉4〈/sub〉/CNTs composite electrode delivers an outstanding specific capacitance of 330 F g〈sup〉−1〈/sup〉 (924 C g〈sup〉−1〈/sup〉) at 1 A g〈sup〉−1〈/sup〉, which is much higher than that of VS〈sub〉2〈/sub〉 with 105 F g〈sup〉−1〈/sup〉 (294 C g〈sup〉−1〈/sup〉). The VS〈sub〉4〈/sub〉/CNTs symmetric supercapacitor (SSC) device exhibits the areal capacitance as high as 676 mF cm〈sup〉−2〈/sup〉 (1488 mC cm〈sup〉−2〈/sup〉) at 0.5 mA cm〈sup〉−2〈/sup〉, and the energy density of 4.55 W h m〈sup〉−2〈/sup〉 (51.2 W h kg〈sup〉−1〈/sup〉) at the power density of 2.75 W m〈sup〉−2〈/sup〉 (30.95 W kg〈sup〉−1〈/sup〉) within a large voltage up to 2.2 V. All the results confirm that VS〈sub〉4〈/sub〉/CNTs composite with petal-shape structures is a promising material for high-performance energy storage devices.〈/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-S0021979719307726-ga1.jpg" width="371" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 15 October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Colloid and Interface Science, Volume 554〈/p〉 〈p〉Author(s): Lingling Ge, Weijie Tong, Qingfa Bian, Duo Wei, Rong Guo〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉 〈h6〉Hypothesis〈/h6〉 〈p〉Various advanced geometries are endowed by the unique structure of “three rooms” of immiscible oils composing the Cerberus droplets. Adjustable interfacial properties and tunable volume ratio in the four-liquid system render it possible to realize the controlled morphology transition by the variation of temperature and emulsion composition.〈/p〉 〈/div〉 〈div〉 〈h6〉Experiments〈/h6〉 〈p〉Cerberus emulsions are prepared in batch scale by traditional one-step vortex mixing, employing the oil combinations of methacryloxypropyl dimethyl silicone (DMS)/2-(perfluorooctyl) ethyl methacrylate (PFOEMA)/vegetable oil (VO). Emulsifier of pluoronic F127, a temperature sensitive surfactant is applied. Stereoscopic topological phase diagram as functions of temperature and composition are plotted. Numerical calculations on the droplet morphology including interface curvature, contact angle, and volume fraction of each domain are performed.〈/p〉 〈/div〉 〈div〉 〈h6〉Findings〈/h6〉 〈p〉Four primary regions with specific morphologies, 〈em〉i〈/em〉.〈em〉e〈/em〉. “VO 〉 DMS 〈 PFOEMA”, “VO 〉 DMS 〉 PFOEMA”, “VO 〈 DMS 〉 PFOEMA”, and finally “VO 〈 DMS 〈 PFOEMA” are obtained. Extended volume ratio range of three lobes, from about 0.03 to 23.3, is achieved and precisely controlled based on the three-phase diagram. What is more, the structural features are found to be thermodynamically determined by the minimization of interfacial energy, though the emulsion is prepared kinetically by vortex mixing. The findings are attractive in the fields of materials synthesis and microreactors.〈/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-S002197971930791X-ga1.jpg" width="290" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 15 November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Applied Catalysis B: Environmental, Volume 257〈/p〉 〈p〉Author(s): Dan Yang, Liyun Cao, Liangliang Feng, Jianfeng Huang, Koji Kajiyoshi, Yongqiang Feng, Qianqian Liu, Wenbin Li, Li Feng, Guojuan Hai〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The synergistic achievement of geometric optimization and surface/interfacial modulation of electrocatalysts for booting the overall efficiency of water splitting is highly desirable yet challenging. Herein, a novel hierarchical Ni〈sub〉3〈/sub〉S〈sub〉2〈/sub〉/VS〈sub〉4〈/sub〉 nanohorn array grown on nickel foam (NS-horn/NF) is prepared by a self-driven synthesis strategy. We demonstrate that 〈em〉in-situ〈/em〉 generation of VS〈sub〉4〈/sub〉 in the NS-horn/NF not only triggers the formation of such unique hierarchical architecture, but favors the graft of enriched active bridging S〈sub〉2〈/sub〉〈sup〉2−〈/sup〉 on the strong coupling interface between Ni〈sub〉3〈/sub〉S〈sub〉2〈/sub〉 and VS〈sub〉4〈/sub〉, and thus the enhanced HER kinetics. More importantly, the abundant active nickel oxides for the OER availably form on the interface benefiting from the surface reconstruction of NS-horn/NF due to the partial leaching of vanadium (IV) of VS〈sub〉4〈/sub〉, which promotes the adsorption of OH〈sup〉−〈/sup〉 and leads to the fast OER rate-determining step in alkaline media. When employed to assemble an alkaline electrolyzer as both anode and cathode, NS-horn/NF electrode only needs a small voltage of 1.57 V to yield 10 mA cm〈sup〉−2〈/sup〉 and retains this activity for at least 70 h. Our findings put forward fresh insights into the rational design of highly efficient bifunctional electrocatalysts toward water spitting for next-generation energy conversion and storage devices.〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0926337319306575-ga1.jpg" width="433" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 5 October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Colloids and Surfaces A: Physicochemical and Engineering Aspects, Volume 578〈/p〉 〈p〉Author(s): Yadan Guo, Chenxi Li, Yiqin Guo, Xuegang Wang, Xiaomeng Li〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Graphitic carbon nitride (g-C〈sub〉3〈/sub〉N〈sub〉4〈/sub〉) is a new type of nonmetal polymeric semiconductor photocatalyst for removal of pollutants. To overcome the low BET surface and the low electron–hole recombination rate of the g-C〈sub〉3〈/sub〉N〈sub〉4〈/sub〉 photocatalysts, we successfully synthesized g-C〈sub〉3〈/sub〉N〈sub〉4〈/sub〉/Na-bentonite composites using an ultrasonic-assisted method. The XRD showed that the composite was composed of g-C〈sub〉3〈/sub〉N〈sub〉4〈/sub〉 and Na-bentonite. The analyses of TEM and XPS indicated that graphite carbon nitride was successfully intercalated on Na-bentonite via the ultrasonic-assisted strategy, and the g-C〈sub〉3〈/sub〉N〈sub〉4〈/sub〉/Na-bentonite nanocomposites presented remarkable light absorption capacities and mesoporous structure observed by UV–vis DRS and BET method. In addition, the as-prepared composites can be used for the photocatalytic removal of single RhB or Cr(VI), and the efficiencies of the Cr(VI) reduction are increased from 53.2% to 88.6% in RhB/Cr(VI) mix-system. Superior stability and high efficiencies of g-C〈sub〉3〈/sub〉N〈sub〉4〈/sub〉/Na-bentonite composites were also exhibited for up to 4 cycles. The photocatalytic enhancement was due to the strong adsorption and the higher charge separation efficiency of as-prepared g-C〈sub〉3〈/sub〉N〈sub〉4〈/sub〉/Na-bentonite composites.〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0927775719306065-ga1.jpg" width="219" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 5 October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Colloids and Surfaces A: Physicochemical and Engineering Aspects, Volume 578〈/p〉 〈p〉Author(s): Lifeng Chen, Zhen Qian, Liang Li, Meilong Fu, Hui Zhao, Lipei Fu, Gang Li〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Water production is getting worse along with the continuous water injection in the reservoir with fracture, but common hydrogels cannot be successfully applied for water shutoff due to its poor resident ability in fracture. In this work, an interpenetrating network hydrogel has been developed innovatively by polyvinyl alcohol (PVA) fiber and common polyacrylamide (PAM) hydrogel. Plugging ability, long-term thermal stability and the interaction between PVA fiber and hydrogel were detailedly studied. Results show that PVA fiber is beneficial to the stability of the PAM hydrogel, and the syneresis rate can be decreased from 30% to 3% on the 120〈sup〉th〈/sup〉 day. PVA fiber accelerates the hydrogel gelation, and the high concentration of fiber leads to good hydrogel strength. PVA fiber increases the amount of the bound water in hydrogel, leading the hydrophilcity increase of hydrogel. An interpenetrating network is formed on the micrometer level, resulting from the three-group crosslinking among polymer, cross-linker and fiber. Compared with common PAM hydrogel, the interpenetrating network hydrogel has better water shutoff effect and EOR performance. Core flow experiment and micromodel test show that the interpenetrating network hydrogel forms an effective bridge in fracture, and it is hard to be moved due to the water washing. The introduction of fiber to hydrogel is an innovative research, which not only improves the water shutoff effect of hydrogel in fracture, but also provides reference to increase the performance of drilling fluid, fracturing solution and EOR polymer utilized in petroleum engineering.〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉 〈p〉Micropresentation of synergistic effect of PVA fiber on PAM solution (A, B) and hydrogel (C, D).〈/p〉 〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0927775719305928-ga1.jpg" width="252" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉 〈/div〉

Description: 〈p〉Publication date: 5 October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Colloids and Surfaces A: Physicochemical and Engineering Aspects, Volume 578〈/p〉 〈p〉Author(s): Krzysztof Kolman, Zareen Abbas〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Molecular dynamics (MD) simulations provide molecular level information about the interaction of organic molecules with the solid surfaces. There has been much development of this method to simulate the interaction of organic molecules with neutral surfaces but relatively less information is available regarding the interactions with charged surfaces. In this study we have developed MD model for the charged silica surface and have investigated the interactions of different benzoic acid derivatives with the charged silica surface in pure and saline water at acidic, neutral and basic pH. The investigated molecules were 2,3-dihydroxybenzoic acid (23DHBA), 3,4-dihydroxybenzoic acid (34DHBA), 1,2,4-benzenetricarboxylic acid (BTCA) and phthalic acid (PHTHA). To simplify the analysis of results, three different simulation systems were considered. Clustering simulations showed how molecules aggregate in solution, pulling simulations provided quantitate information regarding the interactions of single molecule with the silica surface, whereas adsorption simulations focused on the adsorption of multiple molecules on the surface. In general, at pH 2–3, all investigated molecules were clustering and were attracted towards the surface. At pH 7, due to arising electrostatic repulsion, the interactions became weaker which prevented 23DHBA, 34DHBA and BTCA from clustering, however, they continued to adsorb on the silica surface. The adsorption of 23DHBA and 34DHBA decreased significantly at pH 9–10 due to electrostatic repulsion between the molecules and charged silica surface, while BTCA adsorbed slightly stronger due to interactions with ions close to the surface. PHTHA molecules behaved differently by clustering stronger and adsorbing weaker at higher pH. The results of MD simulations presented in this work by using pulling and adsorption approaches provide possibility to compare the results with experimental data.〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0927775719301748-ga1.jpg" width="500" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 5 October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Colloids and Surfaces A: Physicochemical and Engineering Aspects, Volume 578〈/p〉 〈p〉Author(s): José G. Parra, Héctor Domínguez, Yosslen Aray, Peter Iza, Ximena Zarate, Eduardo Schott〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Structural characteristics, interfacial distribution and molecular interactions of the components of the CO〈sub〉2〈/sub〉(gas)/SDS/water/SDS/CO〈sub〉2〈/sub〉(gas) systems as a function of the CO〈sub〉2〈/sub〉(gas)/water interface coverage by the SDS surfactant to different amounts of the CO〈sub〉2〈/sub〉 were studied with molecular dynamics simulations and the NVT ensemble. Initially, the repulsive nonbonding parameter between the water oxygen and CO〈sub〉2〈/sub〉 oxygen was adjusted to improve the prediction of the solvation free energy, solubility of the CO〈sub〉2〈/sub〉 gas in water and the behavior of the CO〈sub〉2〈/sub〉(gas)/SDS/water/SDS/CO〈sub〉2〈/sub〉(gas) systems at molecular level. Our results show that the stability of the studied foams can be improved incrementing of the vapor/water interface coverage with the SDS surfactant and the amount of CO〈sub〉2〈/sub〉 in the system. With the highest interface coverage, the sulfate group has a molecular array more compact at the interface. Furthermore, CO〈sub〉2〈/sub〉 gas have a reduction of the diffusion across of the hydrocarbon chains to the water layer with an increment of the number of CO〈sub〉2〈/sub〉 molecules in the system, indicating a behavior more hydrophobic of the CO〈sub〉2〈/sub〉 gas. The tendencies obtained of the simulations are consistent with the reported experimental results.〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0927775719305989-ga1.jpg" width="239" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 15 November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Applied Catalysis B: Environmental, Volume 257〈/p〉 〈p〉Author(s): Tao Zeng, Shuqi Li, Yi Shen, Haiyan Zhang, Hongru Feng, Xiaole Zhang, Lingxiangyu Li, Zongwei Cai, Shuang Song〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Herein, we designed a novel sodium-doped covalent triazine-based framework with a 3D honeycomb nanoarchitecture (H-CTF-Na) as visible-light-responsive organocatalyst to efficiently drive advanced oxidation processes (AOPs). Experimental and theoretical findings reveal that Na doping narrows the band gap by elevating the band edges and the 3D hierarchical nanocellular morphology improves light harvesting and electron transfer. With these merits, H-CTF-Na showed a photoactivity enhancement of 4.9–6.0-fold for the degradation of carbamazepine (CBZ) compared to those of pristine CTFs and g-C〈sub〉3〈/sub〉N〈sub〉4〈/sub〉 through peroxymonosulfate (PMS) activation under visible-light irradiation. The quenching and EPR results indicate that a synergistic effect between photooxidation (〈em〉h〈sup〉+〈/sup〉〈/em〉) and PMS activation (〈sup〉•〈/sup〉OH and SO〈sub〉4〈/sub〉〈sup〉•−〈/sup〉) derived from the vigorous capture of photogenerated e〈sup〉−〈/sup〉 by PMS is responsible for the marked efficacy of H-CTF-Na/vis/PMS system. Moreover, this system exhibited excellent versatility in degrading other organics (such as various phenols and dyes) and good reusability in terms of five high-efficiency recycled uses.〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0926337319306617-ga1.jpg" width="265" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 15 November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Applied Catalysis B: Environmental, Volume 257〈/p〉 〈p〉Author(s): Zhihong Ye, Enric Brillas, Francesc Centellas, Pere Lluís Cabot, Ignasi Sirés〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The feasibility of destruction of organic pollutants in water at near-neutral pH by homogeneous electro-Fenton (EF) process employing a soluble Fe(III)–EDDS complex as catalyst is demonstrated for the first time. The performance of the Fe(III)–EDDS-assisted EF process with carbon-felt or air-diffusion cathodes was evaluated from the degradation of butylated hydroxyanisole (BHA) in sulfate medium. The influence of applied current, pH and Fe(III):EDDS ratio and dosage on BHA decay and mineralization was related to the evolution of H〈sub〉2〈/sub〉O〈sub〉2〈/sub〉 and iron concentrations. Using Fe(III)–EDDS, up to 50% Fe(II) regeneration was achieved in 10 min, whereas only 23% was transformed using hydrated Fe〈sup〉3+〈/sup〉. Almost total removal of BHA was achieved thanks to homogenous Fenton, heterogeneous Fenton with cathodically adsorbed Fe(III), and electrocatalysis. The mineralization partly corresponded to the gradual destruction of EDDS by hydroxyl radical (〈em〉k〈/em〉〈sub〉abs〈/sub〉 = 5.22 × 10〈sup〉9〈/sup〉 M〈sup〉−1〈/sup〉 s〈sup〉−1〈/sup〉), and involved the formation of 5 oxidation and 6 dimerization or cyclization by-products.〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0926337319306538-ga1.jpg" width="327" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 15 November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Applied Catalysis B: Environmental, Volume 257〈/p〉 〈p〉Author(s): Jiangyao Chen, Zhigui He, Yuemeng Ji, Guiying Li, Taicheng An, Wonyong Choi〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The photocatalytic transformation mechanisms of styrene, were compared in TiO〈sub〉2〈/sub〉 system under ultraviolet (UV) and vacuum ultraviolet (VUV) irradiations. TiO〈sub〉2〈/sub〉/VUV displayed higher photocatalytic degradation and mineralization efficiencies (100% and 51% within 8 min) than TiO〈sub〉2〈/sub〉/UV (86% and 21% within 60 min), and the increased efficiencies were contributed from enhanced production of 〈sup〉〈img src="https://sdfestaticassets-eu-west-1.sciencedirectassets.com/shared-assets/16/entities/rad"〉〈/sup〉OH through VUV photolysis of H〈sub〉2〈/sub〉O and O〈sub〉2〈/sub〉. The addition reactions of these enhanced 〈sup〉〈img src="https://sdfestaticassets-eu-west-1.sciencedirectassets.com/shared-assets/16/entities/rad"〉〈/sup〉OH converted styrene to benzaldehyde and other small molecular carbonyl compounds in TiO〈sub〉2〈/sub〉/VUV gas system. Due to absence of atmospheric 〈sup〉〈img src="https://sdfestaticassets-eu-west-1.sciencedirectassets.com/shared-assets/16/entities/rad"〉〈/sup〉OH in TiO〈sub〉2〈/sub〉/UV system, styrene underwent cycloisomerisation to form a bicyclic byproduct, benzocyclobutene, which further transformed to benzocyclobutenone, benzocyclobutenol, phthalan, phthalide and phthalic anhydride on photocatalyst TiO〈sub〉2〈/sub〉. Meanwhile, both systems shared same pathways from styrene to monoaromatic alcohols, ketones, aldehydes on TiO〈sub〉2〈/sub〉 through 〈sup〉〈img src="https://sdfestaticassets-eu-west-1.sciencedirectassets.com/shared-assets/16/entities/rad"〉〈/sup〉OH addition. Our results provide a deep insight into 〈sup〉〈img src="https://sdfestaticassets-eu-west-1.sciencedirectassets.com/shared-assets/16/entities/rad"〉〈/sup〉OH-determined photocatalytic transformation mechanism of AHs and their final fate in atmospheric environment.〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0926337319306587-ga1.jpg" width="247" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 5 October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Colloids and Surfaces A: Physicochemical and Engineering Aspects, Volume 578〈/p〉 〈p〉Author(s): M. Jinish Antony, C. Albin Jolly, K. Rohini Das, T.S. Swathy〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉We report here the synthesis of polyaniline (PANI) nanomaterials using sodium bis (2-ethylhexyl) sulfosuccinate (AOT) micelles assisted chemical oxidative interfacial polymerization. We have employed two interfaces (chloroform-water and hexane-water) and two oxidizing agents (ammonium persulfate and ferric chloride). The anionic surfactant sodium bis (2-ethylhexyl) sulfosuccinate (AOT) forms normal micelles in aqueous solution and reverse micelles in hydrophobic solvents like hexane or chloroform. The factors influencing the properties and morphologies of polyaniline nanomaterials such as monomer: surfactant ratio, monomer: oxidant ratio, types of interfaces and oxidants used have been studied. Powder X-ray diffraction of the polyaniline nanomaterials have revealed that polyaniline samples were semi-crystalline in nature. Morphology of polyaniline samples studied by scanning electron microscopy (SEM) and transmission electron microscopy (TEM) have revealed that most of the polyaniline nanomaterials synthesized using ferric chloride possess spherical nature, whereas polyaniline samples synthesized using ammonium persulfate (APS) possess short nanofibers especially at lower aniline/AOT mole ratio in feed (12.5–6.5). The four probe electrical conductivity of the samples were found to be of the order of 1.8 × 10〈sup〉−1〈/sup〉 to 8.6 × 10〈sup〉−1〈/sup〉 S/cm. Thermal stability of the polyaniline samples recorded by thermogravimetric analysis (TGA) have revealed that polyaniline samples were thermally stable up to 275 °C for 10% weight loss. Interfacial polymerization of aniline monomer using reverse micelles of AOT in hexane phase and ammonium persulfate as oxidizing agent in aqueous phase have been proved to be efficient method for the synthesis of short polyaniline nanofibers.〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0927775719306090-ga1.jpg" width="316" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: July–August 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Materials Today, Volume 27〈/p〉 〈p〉Author(s): 〈/p〉