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Frontiers in Chemistry

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https://www.readbyqxmd.com/read/30013970/progress-of-research-in-negative-thermal-expansion-materials-paradigm-shift-in-the-control-of-thermal-expansion
#1
REVIEW
Koshi Takenaka
To meet strong demands for the control of thermal expansion necessary because of the advanced development of industrial technology, widely various giant negative thermal expansion (NTE) materials have been developed during the last decade. Discovery of large isotropic NTE in ZrW2 O8 has greatly advanced research on NTE deriving from its characteristic crystal structure, which is now classified as conventional NTE. Materials classified in this category have increased rapidly. In addition to development of conventional NTE materials, remarkable progress has been made in phase-transition-type NTE materials using a phase transition accompanied by volume contraction upon heating...
2018: Frontiers in Chemistry
https://www.readbyqxmd.com/read/30013969/effects-of-zirconium-doping-into-a-monoclinic-scheelite-bivo-4-crystal-on-its-structural-photocatalytic-and-photoelectrochemical-properties
#2
Shigeru Ikeda, Takato Kawaguchi, Yui Higuchi, Naoto Kawasaki, Takashi Harada, Mikas Remeika, Muhammad M Islam, Takeaki Sakurai
Effects of zirconium (Zr) doping into BiVO4 powder on its structural properties and photocatalytic activity for O2 evolution were examined. The formation of BiVO4 powder crystallized in a monoclinic scheelite structure ( ms -BiVO4 ) was achieved when the sample was doped with a relatively small amount of Zr. The photocatalytic activity of Zr-doped ms -BiVO4 powder was much higher than that of non-doped ms -BiVO4 . However, further doping caused a reduction of photocatalytic activity for O2 evolution due to the occurrence of structural alterations into tetragonal scheelite and tetragonal zircon structures...
2018: Frontiers in Chemistry
https://www.readbyqxmd.com/read/30013968/two-novel-small-molecule-donors-and-the-applications-in-bulk-heterojunction-solar-cells
#3
Xin Qi, Yuan-Chih Lo, Yifan Zhao, Liyang Xuan, Hao-Chun Ting, Ken-Tsung Wong, Mostafizur Rahaman, Zhijian Chen, Lixin Xiao, Bo Qu
Two novel small molecules DTRDTQX and DTIDTQX , based on ditolylaminothienyl group as donor moiety and quinoxaline as middle acceptor moiety with different terminal acceptor groups were synthesized and characterized in this work. In order to study the photovoltaic properties of DTRDTQX and DTIDTQX , bulk-heterojunction solar cells with the configuration of FTO/c-TiO2 / DTRDTQX (or DTIDTQX ):C70 /MoO3 /Ag were fabricated, in which DTRDTQX and DTIDTQX acted as the donors and neat C70 as the acceptor. When the weight ratio of DTRDTQX :C70 reached 1:2 and the active layer was annealed at 100°C, the optimal device was realized with the power conversion efficiency (PCE) of 1...
2018: Frontiers in Chemistry
https://www.readbyqxmd.com/read/30013967/dynamic-surface-wetting-and-heat-transfer-in-a-droplet-particle-system-of-less-than-unity-size-ratio
#4
Subhasish Mitra, Geoffrey Evans
Dynamic surface wetting of particles in contact with droplet is a complex phenomenon ubiquitously encountered in many multiphase systems of industrial importance. In this study, we address this aspect by investigating impact behavior of a water droplet (diameter = 2.9 ± 0.1 mm) in the Weber number ( We ) range from ~4 to 104 on a stationary spherical brass particle (diameter = 10 mm) with and without heat transfer using a combination of high speed imaging and computational fluid dynamics (CFD) modeling approach...
2018: Frontiers in Chemistry
https://www.readbyqxmd.com/read/30013966/ag-3-vo-4-nanoparticles-decorated-bi-2-o-2-co-3-micro-flowers-an-efficient-visible-light-driven-photocatalyst-for-the-removal-of-toxic-contaminants
#5
Shijie Li, Shiwei Hu, Wei Jiang, Yu Liu, Yanping Liu, Yingtang Zhou, Liuye Mo, Jianshe Liu
Semiconductor-based photocatalysis is of great potential for tackling the environmental pollution. Herein, a novel hierarchical heterostructure of Bi2 O2 CO3 micro-flowers in-situ decorated with Ag3 VO4 nanoparticles was developed by a facile method. Various characterization techniques have been employed to study the physical and chemical property of the novel catalyst. The novel catalyst was utilized for the photocatalytic removal of industrial dyes (rhodamine B, methyl orange) and tetracycline antibiotic under visible-light irradiation...
2018: Frontiers in Chemistry
https://www.readbyqxmd.com/read/30013965/huanglongmycin-a-c-cytotoxic-polyketides-biosynthesized-by-a-putative-type-ii-polyketide-synthase-from-streptomyces-sp-cb09001
#6
Lin Jiang, Hong Pu, Jingxi Xiang, Meng Su, Xiaohui Yan, Dong Yang, Xiangcheng Zhu, Ben Shen, Yanwen Duan, Yong Huang
Three natural products of nonaketide biosynthetic origin, probably biosynthesized from nine molecules of malonyl-CoA, have been isolated. Herein we described the isolation and structure elucidation of huanglongmycin (HLM) A-C and identification of the putative hlm biosynthetic gene cluster from Streptomyces sp. CB09001, isolated from a karstic cave in Xiangxi, China. Albeit previously isolated, HLM A was reported for the first time to exhibit moderate cytotoxicity against A549 lung cancer cell line (IC50 = 13...
2018: Frontiers in Chemistry
https://www.readbyqxmd.com/read/30013964/-in-silico-workflow-for-the-discovery-of-natural-products-activating-the-g-protein-coupled-bile-acid-receptor-1
#7
Benjamin Kirchweger, Jadel M Kratz, Angela Ladurner, Ulrike Grienke, Thierry Langer, Verena M Dirsch, Judith M Rollinger
The G protein-coupled bile acid receptor (GPBAR1) has been recognized as a promising new target for the treatment of diverse diseases, including obesity, type 2 diabetes, fatty liver disease and atherosclerosis. The identification of novel and potent GPBAR1 agonists is highly relevant, as these diseases are on the rise and pharmacological unmet therapeutic needs are pervasive. Therefore, the aim of this study was to develop a proficient workflow for the in silico prediction of GPBAR1 activating compounds, primarily from natural sources...
2018: Frontiers in Chemistry
https://www.readbyqxmd.com/read/30013963/synthesis-and-characterization-of-photoresponsive-macromolecule-for-biomedical-application
#8
Juan Pang, Ziyu Gao, Long Zhang, Huiming Wang, Xiaohong Hu
Azobenzene, a photo switcher, has attracted increasing interest due to its structural response to photo stimulus in the field of information science and chemical sensing in the recent decades. However, limited water solubility and cytotoxicity restrained their applications in the biomedical field. In research, HA-AZO has been designed as a water soluble photo switcher in biomedical application. Synthesized HA-AZO had good water-solubility and a stable π-π* transition absorbance peak trans-isomer. With exposure to UV, transformation from trans-isomer to cis-isomer of HA-AZO could be realized according to UV spectra...
2018: Frontiers in Chemistry
https://www.readbyqxmd.com/read/30009159/multisensor-systems-by-electrochemical-nanowire-assembly-for-the-analysis-of-aqueous-solutions
#9
Konstantin G Nikolaev, Yury E Ermolenko, Andreas Offenhäusser, Sergey S Ermakov, Yulia G Mourzina
The development of electrochemical multisensor systems is driven by the need for fast, miniature, inexpensive, analytical devices, and advanced interdisciplinary based on both chemometric and (nano)material approaches. A multicomponent analysis of complex mixtures in environmental and technological monitoring, biological samples, and cell culture requires chip-based multisensor systems with high-stability sensors. In this paper, we describe the development, characterization, and applications of chip-based nanoelectrochemical sensor arrays prepared by the directed electrochemical nanowire assembly (DENA) of noble metals and metal alloys to analyze aqueous solutions...
2018: Frontiers in Chemistry
https://www.readbyqxmd.com/read/30003079/a-plasma-biochemical-analysis-of-acute-lead-poisoning-in-a-rat-model-by-chemometrics-based-fourier-transform-infrared-spectroscopy-an-exploratory-study
#10
Wenli Tian, Dan Wang, Haoran Fan, Lujuan Yang, Gang Ma
In this work, we explored to use chemometrics-based Fourier transform infrared (FTIR) spectroscopy to investigate the plasma biochemical changes due to acute lead poisoning (ALP) in a rat model. We first collected the FTIR spectra of the plasma samples from the rats with and without suffering from ALP. We then performed the chemometric analysis of these FTIR spectra using principal component analysis (PCA) and partial least squares discriminant analysis (PLS-DA). We found that the chemometrics-based FTIR spectroscopy can discriminate the rats with and without ALP...
2018: Frontiers in Chemistry
https://www.readbyqxmd.com/read/30003078/a-fluorescent-sensor-array-based-on-heteroatomic-macrocyclic-fluorophores-for-the-detection-of-polluting-species-in-natural-water-samples
#11
Larisa Lvova, Fabrizio Caroleo, Alessandra Garau, Vito Lippolis, Luca Giorgi, Vieri Fusi, Nelsi Zaccheroni, Marco Lombardo, Luca Prodi, Corrado Di Natale, Roberto Paolesse
The development of a novel all-solid-state optical sensor array based on heteroatomic macrocyclic fluorophores (diaza-crown ether, metallocorrole and pyridinophans) for the photographic analysis of liquid media, is presented. The sensitivity of the new optical system toward a number of different species (cations: Li+ , K+ , Na+ , <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msubsup> <mml:mrow> <mml:mtext>NH</mml:mtext> </mml:mrow> <mml:mrow> <mml:mn>4</mml:mn> </mml:mrow> <mml:mrow> <mml:mo>+</mml:mo> </mml:mrow> </mml:msubsup> </mml:math> , Mg2+ , Ca2+ , Co2+ , Cu2+ , Zn2+ , Cd2+ , Pb2+ and anions: <mml:math xmlns:mml="http://www...
2018: Frontiers in Chemistry
https://www.readbyqxmd.com/read/30003077/the-anisotropic-thermal-expansion-of-non-linear-optical-crystal-baalbo-3-f-2-below-room-temperature
#12
Xingxing Jiang, Naizheng Wang, Maxim S Molokeev, Wei Wang, Shibin Guo, Rongjin Huang, Laifeng Li, Zhanggui Hu, Zheshuai Lin
Thermal expansion is a crucial factor for the performance of laser devices, since the induced thermal stress by laser irradiation would strongly affect the optical beam quality. For BaAlBO3 F2 (BABF), a good non-linear optical (NLO) crystal, due to the highly anisotropic thermal expansion its practical applications are strongly affected by the "tearing" stress with the presence of local overheating area around the laser spot. Recently, the strategy to place the optical crystals in low-temperature environment to alleviate the influence of the thermal effect has been proposed...
2018: Frontiers in Chemistry
https://www.readbyqxmd.com/read/30003076/qm-cluster-or-qm-mm-in-computational-enzymology-the-test-case-of-ligw-decarboxylase
#13
Mario Prejanò, Tiziana Marino, Nino Russo
The catalytic mechanism of the decarboxylation of 5-carboxyvanillate by LigW producing vanillic acid has been studied by using QM cluster and hybrid QM/MM methodologies. In the QM cluster model, the environment of a small QM model is treated with a bulky potential while two QM/MM models studies include partial and full protein with and without explicitly treated water solvent. The studied reaction involves two sequential steps: the protonation of the carbon of the 5-carboxy-vanillate substrate and the decarboxylation of the intermediate from which results deprotonated vanillic acid as product...
2018: Frontiers in Chemistry
https://www.readbyqxmd.com/read/30003075/p2rx7-purinoceptor-as-a-therapeutic-target-the-second-coming
#14
REVIEW
Chris N J Young, Dariusz C Górecki
The P2RX7 receptor is a unique member of a family of extracellular ATP (eATP)-gated ion channels expressed in immune cells, where its activation triggers the inflammatory cascade. Therefore, P2RX7 has been long investigated as a target in the treatment of infectious and inflammatory diseases. Subsequently, P2RX7 signaling has been documented in other physiological and pathological processes including pain, CNS and psychiatric disorders and cancer. As a result, a range of P2RX7 antagonists have been developed and trialed...
2018: Frontiers in Chemistry
https://www.readbyqxmd.com/read/30003074/oenin-and-quercetin-copigmentation-highlights-from-density-functional-theory
#15
Yunkui Li, Mario Prejanò, Marirosa Toscano, Nino Russo
Making use of anthocyanin copigmentation, it is possible to effectively improve color quality and stability of red wines and other foods. This can be done by selecting strong copigments, but a 1-fold experimental screening usually entails a high cost and a low efficiency. The aim of this work is to show how a theoretical model based on density functional theory can be useful for an accurate and rapid prediction of copigmentation ability of a copigment. The present study, concerning the copigmentation between oenin and quercetin under the framework of implicit solvent, indicates that, in these conditions, the intermolecular hydrogen bonds play an important role in the system stabilization...
2018: Frontiers in Chemistry
https://www.readbyqxmd.com/read/29998097/editorial-the-chemistry-of-imaging-probes
#16
EDITORIAL
Lorenzo Tei, Zsolt Baranyai
No abstract text is available yet for this article.
2018: Frontiers in Chemistry
https://www.readbyqxmd.com/read/29998096/covalent-attachment-of-enzymes-to-paper-fibers-for-paper-based-analytical-devices
#17
Alexander Böhm, Simon Trosien, Olga Avrutina, Harald Kolmar, Markus Biesalski
Due to its unique material properties, paper offers many practical advantages as a viable platform for sensing devices. In view of paper-based microfluidic biosensing applications, the covalent immobilization of enzymes with preserved functional activity is highly desirable and ultimately challenging. In the present manuscript, we report an efficient approach to achieving the covalent attachment of certain enzymes on paper fibers via a surface-bound network of hydrophilic polymers bearing protein-modifiable sites...
2018: Frontiers in Chemistry
https://www.readbyqxmd.com/read/29998095/probing-substituents-in-the-1-and-3-position-tetrahydropyrazino-annelated-water-soluble-xanthine-derivatives-as-multi-target-drugs-with-potent-adenosine-receptor-antagonistic-activity
#18
Pierre Koch, Andreas Brunschweiger, Vigneshwaran Namasivayam, Stefan Ullrich, Annalisa Maruca, Beatrice Lazzaretto, Petra Küppers, Sonja Hinz, Jörg Hockemeyer, Michael Wiese, Jag Heer, Stefano Alcaro, Katarzyna Kiec-Kononowicz, Christa E Müller
Tetrahydropyrazino-annelated theophylline (1,3-dimethylxanthine) derivatives have previously been shown to display increased water-solubility as compared to the parent xanthines due to their basic character. In the present study, we modified this promising scaffold by replacing the 1,3-dimethyl residues by a variety of alkyl groups including combinations of different substituents in both positions. Substituted benzyl or phenethyl residues were attached to the N8 of the resulting 1,3-dialkyl-tetrahydropyrazino[2,1- f ]purinediones with the aim to obtain multi-target drugs that block human A1 and A2A adenosine receptors (ARs) and monoaminoxidase B (MAO-B)...
2018: Frontiers in Chemistry
https://www.readbyqxmd.com/read/29998094/a-theoretical-study-of-the-benzoylformate-decarboxylase-reaction-mechanism
#19
Ferran Planas, Xiang Sheng, Michael J McLeish, Fahmi Himo
Density functional theory calculations are used to investigate the detailed reaction mechanism of benzoylformate decarboxylase, a thiamin diphosphate (ThDP)-dependent enzyme that catalyzes the nonoxidative decarboxylation of benzoylformate yielding benzaldehyde and carbon dioxide. A large model of the active site is constructed on the basis of the X-ray structure, and it is used to characterize the involved intermediates and transition states and evaluate their energies. There is generally good agreement between the calculations and available experimental data...
2018: Frontiers in Chemistry
https://www.readbyqxmd.com/read/29988578/application-of-light-scattering-techniques-to-nanoparticle-characterization-and-development
#20
REVIEW
Patrícia M Carvalho, Mário R Felício, Nuno C Santos, Sónia Gonçalves, Marco M Domingues
Over the years, the scientific importance of nanoparticles for biomedical applications has increased. The high stability and biocompatibility, together with the low toxicity of the nanoparticles developed lead to their use as targeted drug delivery systems, bioimaging systems, and biosensors. The wide range of nanoparticles size, from 10 nm to 1 μm, as well as their optical properties, allow them to be studied using microscopy and spectroscopy techniques. In order to be effectively used, the physicochemical properties of nanoparticle formulations need to be taken into account, namely, particle size, surface charge distribution, surface derivatization and/or loading capacity, and related interactions...
2018: Frontiers in Chemistry
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