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https://www.readbyqxmd.com/read/28226221/development-of-new-density-functional-approximations
#1
Neil Qiang Su, Xin Xu
Kohn-Sham density functional theory has become the leading electronic structure method for atoms, molecules, and extended systems. It is in principle exact, but any practical application must rely on density functional approximations (DFAs) for the exchange-correlation energy. Here we emphasize four aspects of the subject: (a) philosophies and strategies for developing DFAs; (b) classification of DFAs; (c) major sources of error in existing DFAs; and (d) some recent developments and future directions. Expected final online publication date for the Annual Review of Physical Chemistry Volume 68 is April 20, 2017...
February 22, 2017: Annual Review of Physical Chemistry
https://www.readbyqxmd.com/read/28225616/a-straightforward-approach-for-3d-bacterial-printing
#2
Benjamin A E Lehner, Dominik T Schmieden, Anne Sara Meyer
Sustainable and personally tailored materials production is an emerging challenge to society. Living organisms can produce and pattern an extraordinarily wide range of different molecules in a sustainable way. These natural systems offer an abundant source of inspiration for the development of new environmentally-friendly materials production techniques. In this paper, we describe the first steps towards the 3-dimensional printing of bacterial cultures for materials production and patterning. This methodology combines the capability of bacteria to form new materials with the reproducibility and tailored approach of 3D printing systems...
February 22, 2017: ACS Synthetic Biology
https://www.readbyqxmd.com/read/28225607/reactivity-study-of-unsymmetrical-%C3%AE-diketiminato-copper-i-complexes-effect-of-the-chelating-ring
#3
Wan-Jung Chuang, Sung-Po Hsu, Kuldeep Chand, Fu-Lun Yu, Cheng-Long Tsai, Yu-Hsuan Tseng, Yuh-Hsiu Lu, Jen-Yu Kuo, James R Carey, Hsuan-Ying Chen, Hsing-Yin Chen, Michael Y Chiang, Sodio C N Hsu
β-Diketiminato copper(I) complexes play important roles in bioinspired catalytic chemistry and in applications to the materials industry. However, it has been observed that these complexes are very susceptible to disproportionation. Coordinating solvents or Lewis bases are typically used to prevent disproportionation and to block the coordination sites of the copper(I) center from further decomposition. Here, we incorporate this coordination protection directly into the molecule in order to increase the stability and reactivity of these complexes and to discover new copper(I) binding motifs...
February 22, 2017: Inorganic Chemistry
https://www.readbyqxmd.com/read/28224767/effect-of-accreditation-on-accuracy-of-diagnostic-tests-in-medical-laboratories
#4
Mi Ae Jang, Young Ahn Yoon, Junghan Song, Jeong Ho Kim, Won Ki Min, Ji Sung Lee, Yong Wha Lee, You Kyoung Lee
BACKGROUND: Medical laboratories play a central role in health care. Many laboratories are taking a more focused and stringent approach to quality system management. In Korea, laboratory standardization efforts undertaken by the Korean Laboratory Accreditation Program (KLAP) and the Korean External Quality Assessment Scheme (KEQAS) may have facilitated an improvement in laboratory performance, but there are no fundamental studies demonstrating that laboratory standardization is effective...
May 2017: Annals of Laboratory Medicine
https://www.readbyqxmd.com/read/28224395/ion-mobility-studies-on-the-negative-ion-molecule-chemistry-of-isoflurane-and-enflurane
#5
Ramón González-Méndez, Peter Watts, David C Howse, Immacolata Procino, Henry McIntyre, Chris A Mayhew
In the present work we present an investigation of the negative ion-molecule chemistry of the anaesthetics isoflurane, ISOF, and enflurane, ENF, in an ion mobility spectrometry/mass spectrometry (IMS/MS), in both air and nitrogen. Hexachloroethane (HCE) was introduced in both air and nitrogen to produce Cl(-) as a reactant ion. This study was undertaken owing to uncertainties in the chemical processes, which lead to the cluster ions reported in other work (Eiceman et al. Anal. Chem. 61, 1093-1099, 1). In particular for ISOF the product ion observed was ISOF...
February 21, 2017: Journal of the American Society for Mass Spectrometry
https://www.readbyqxmd.com/read/28224156/binding-of-ligands-containing-carbonyl-and-phenol-groups-to-iron-iii-new-fe6-fe10-and-fe12-coordination-clusters
#6
Alexandros A Kitos, Constantina Papatriantafyllopoulou, Anastasios J Tasiopoulos, Spyros P Perlepes, Albert Escuer, Vassilios Nastopoulos
The initial use of ligands 2'-hydroxyacetophenone (HL(1)), 2-hydroxybenzophenone (HL(2)) and 2,2'-dihydroxybenzophenone (H2L(3)) in iron(iii) chemistry is described. The syntheses and crystal structures are reported for five iron(iii) clusters: [Fe10O4(OMe)14(L(1))6(MeOH)2](NO3)2·3MeOH (1·3MeOH), [Fe12O4(OH)(OMe)17(L(1))8](ClO4)2·2H2O (2·2H2O), [Fe10O4(OMe)14Cl4(L(2))4(MeOH)2] (3), [Fe10O4(OMe)14(L(2))6(py)2](ClO4)2·MeOH (4·MeOH), where py = pyridine, and [Fe6O2(OEt)6(O2CMe)2(L(3))2(HL(3))2] (5). The molecular structures of the decanuclear clusters 1, 3 and 4 are organized around a {Fe10(μ4-O)4(μ3-OMe)2(μ-OMe)12}(8+) core consisting of ten {Fe3O4} face-sharing defective cubane units...
February 22, 2017: Dalton Transactions: An International Journal of Inorganic Chemistry
https://www.readbyqxmd.com/read/28221786/chemical-trends-in-solid-alkali-pertechnetates
#7
Jamie Weaver, Chuck Z Soderquist, Nancy M Washton, Andrew S Lipton, Paul L Gassman, Wayne W Lukens, Albert A Kruger, Nathalie A Wall, John S McCloy
Insight into the solid-state chemistry of pure technetium-99 ((99)Tc) oxides is required in the development of a robust immobilization and disposal system for nuclear waste stemming from the radiopharmaceutical industry, from the production of nuclear weapons, and from spent nuclear fuel. However, because of its radiotoxicity and the subsequent requirement of special facilities and handling procedures for research, only a few studies have been completed, many of which are over 20 years old. In this study, we report the synthesis of pure alkali pertechnetates (sodium, potassium, rubidium, and cesium) and analysis of these compounds by Raman spectroscopy, X-ray absorption spectroscopy (XANES and EXAFS), solid-state nuclear magnetic resonance (static and magic angle spinning), and neutron diffraction...
February 21, 2017: Inorganic Chemistry
https://www.readbyqxmd.com/read/28221714/photonic-devices-out-of-equilibrium-transient-memory-signal-propagation-and-sensing
#8
Thomas Heuser, Rémi Merindol, Sebastian Loescher, Aileen Klaus, Andreas Walther
Soft photonic materials are important for sensors, displays, or energy management and have become switchable under static equilibrium conditions by integration of responsive polymer features. The next step is to equip such materials with the ability for autonomously dynamic and self-regulating behavior, which would advance their functionality and application possibilities to new levels. Here, this study shows the system integration of a nonlinear, biocatalytic pH-feedback system with a pH-responsive block copolymer photonic gel, and demonstrates autonomous transient memories, remotely controlled signal propagation, and sensing...
February 21, 2017: Advanced Materials
https://www.readbyqxmd.com/read/28221385/ir-spectroscopic-investigations-of-chemical-and-photochemical-reactions-on-metal-oxides-bridging-the-materials-gap
#9
REVIEW
Yuemin Wang, Christof Wöll
In this review, we highlight recent progress (2008-2016) in infrared reflection absorption spectroscopy (IRRAS) studies on oxide powders achieved by using different types of metal oxide single crystals as reference systems. Precise polarization- and azimuth-dependent IRRAS data recorded for single crystal substrates has allowed for fundamental insights into the surface chemistry and photochemistry of numerous probe molecules on various surfaces exposed by three very important metal oxides (ZnO, TiO2, and CeO2)...
February 21, 2017: Chemical Society Reviews
https://www.readbyqxmd.com/read/28221369/chemistry-based-molecular-signature-underlying-the-atypia-of-clozapine
#10
T Cardozo, E Shmelkov, K Felsovalyi, J Swetnam, T Butler, D Malaspina, S V Shmelkov
The central nervous system is functionally organized as a dynamic network of interacting neural circuits that underlies observable behaviors. At higher resolution, these behaviors, or phenotypes, are defined by the activity of a specific set of biomolecules within those circuits. Identification of molecules that govern psychiatric phenotypes is a major challenge. The only organic molecular entities objectively associated with psychiatric phenotypes in humans are drugs that induce psychiatric phenotypes and drugs used for treatment of specific psychiatric conditions...
February 21, 2017: Translational Psychiatry
https://www.readbyqxmd.com/read/28220995/development-of-hydrogels-for-regenerative-engineering
#11
REVIEW
Xiaofei Guan, Meltem Avci-Adali, Emine Alarçin, Hao Cheng, Sara Saheb Kashaf, Yuxiao Li, Aditya Chawla, Hae Lin Jang, Ali Khademhosseini
The aim of regenerative engineering is to restore complex tissues and biological systems through convergence in the fields of advanced biomaterials, stem cell science, and developmental biology. Hydrogels are one of the most attractive biomaterials for regenerative engineering, since they can be engineered into tissue mimetic 3D scaffolds to support cell growth due to their similarity to native extracellular matrix. Advanced nano- and micro-technologies have dramatically increased the ability to control properties and functionalities of hydrogel materials by facilitating biomimetic fabrication of more sophisticated compositions and architectures, thus extending our understanding of cell-matrix interactions at the nanoscale...
February 21, 2017: Biotechnology Journal
https://www.readbyqxmd.com/read/28220176/chemical-routes-to-discharging-graphenides
#12
Stephen A Hodge, David J Buckley, Hin Chun Yau, Neal T Skipper, Christopher A Howard, Milo S P Shaffer
Chemical and electrochemical reduction methods allow the dispersion, processing, and/or functionalization of discrete sp(2)-hybridised nanocarbons, including fullerenes, nanotubes and graphenes. Electron transfer to the nanocarbon raises the Fermi energy, creating nanocarbon anions and thereby activating an array of possible covalent reactions. The Fermi level may then be partially or fully lowered by intended functionalization reactions, but in general, techniques are required to remove excess charge without inadvertent covalent reactions that potentially degrade the nanocarbon properties of interest...
February 21, 2017: Nanoscale
https://www.readbyqxmd.com/read/28218326/diffusive-confinement-of-free-radical-intermediates-in-the-oh-radical-oxidation-of-semisolid-aerosols
#13
Aaron A Wiegel, Matthew J Liu, William D Hinsberg, Kevin R Wilson, Frances A Houle
Multiphase chemical reactions (gas + solid/liquid) involve a complex interplay between bulk and interface chemistry, diffusion, evaporation, and condensation. Reactions of atmospheric aerosols are an important example of this type of chemistry: the rich array of particle phase states and multiphase transformation pathways produce diverse but poorly understood interactions between chemistry and transport. Their chemistry is of intrinsic interest because of their role in controlling climate. Their characteristics also make them useful models for the study of principles of reactivity of condensed materials under confined conditions...
February 20, 2017: Physical Chemistry Chemical Physics: PCCP
https://www.readbyqxmd.com/read/28216567/wine-flavonoids-in-health-and-disease-prevention
#14
Iva Fernandes, Rosa Pérez-Gregorio, Susana Soares, Nuno Mateus, Victor de Freitas
Wine, and particularly red wine, is a beverage with a great chemical complexity that is in continuous evolution. Chemically, wine is a hydroalcoholic solution (~78% water) that comprises a wide variety of chemical components, including aldehydes, esters, ketones, lipids, minerals, organic acids, phenolics, soluble proteins, sugars and vitamins. Flavonoids constitute a major group of polyphenolic compounds which are directly associated with the organoleptic and health-promoting properties of red wine. However, due to the insufficient epidemiological and in vivo evidences on this subject, the presence of a high number of variables such as human age, metabolism, the presence of alcohol, the complex wine chemistry, and the wide array of in vivo biological effects of these compounds suggest that only cautious conclusions may be drawn from studies focusing on the direct effect of wine and any specific health issue...
February 14, 2017: Molecules: a Journal of Synthetic Chemistry and Natural Product Chemistry
https://www.readbyqxmd.com/read/28215631/posttranscriptional-chemical-labeling-of-rna-by-using-bioorthogonal-chemistry
#15
REVIEW
Jerrin Thomas George, Seergazhi G Srivatsan
Recent developments in RNA labeling technology have provided viable tools to analyze RNA synthesis, processing and function in cell-free and cellular environments. Notably, emerging methodologies based on posttranscriptional chemical labeling by using bioorthogonal chemistry have enabled the visualization and profiling of exogenous and endogenous RNA transcripts. In this review, we first give an overview of different RNA labeling strategies based on chemical as well as genetically encoded systems. Subsequently, we provided a detailed discussion on methodologies that have been developed to introduce various bioorthogonal reactive groups into RNA transcripts, which are compatible for posttranscriptional functionalization...
February 16, 2017: Methods: a Companion to Methods in Enzymology
https://www.readbyqxmd.com/read/28213248/multi-reverse-flow-injection-analysis-integrated-with-multi-optical-sensor-for-simultaneous-determination-of-mn-ii-fe-ii-cu-ii-and-fe-iii-in-natural-waters
#16
Napaporn Youngvises, Kittigan Suwannasaroj, Jaroon Jakmunee, Awadh AlSuhaimi
Multi-reverse flow injection analysis (Mr-FIA) integrated with multi-optical sensor was developed and optimized for the simultaneous determination of multi ions; Mn(II), Fe(II), Cu(II) and Fe(III) in water samples. The sample/standard solutions were propelled making use of a four channels peristaltic pump whereas 4 colorimetric reagents specific for the metal ions were separately injected in sample streams using multi-syringe pump. The color zones that formed in the individual mixing coils were then streamed into multi-channels spectrometer, which comprised of four flows through cell and four pairs of light emitting diode and photodiode, whereby signals were measured concurrently...
May 1, 2017: Talanta
https://www.readbyqxmd.com/read/28213182/microbial-nickel-cellular-uptake-and-delivery-to-enzyme-centers
#17
REVIEW
Conor J Zeer-Wanklyn, Deborah B Zamble
Nickel enzymes allow microorganisms to access chemistry that can be vital for survival and virulence. In this review we highlight recent work on several systems that import nickel ions and deliver them to the active sites of these enzymes. Small molecules, in particular l-His and derivatives, may chelate nickel ions before import at TonB-dependent outer-membrane and ABC-type inner-membrane transporters. Inside the cell, nickel ions are used by maturation factors required to produce nickel enzymes such as [NiFe]-hydrogenase, urease and lactate racemase...
February 14, 2017: Current Opinion in Chemical Biology
https://www.readbyqxmd.com/read/28213091/convergence-of-hepcidin-deficiency-systemic-iron-overloading-heme-accumulation-and-rev-erb%C3%AE-%C3%AE-activation-in-aryl-hydrocarbon-receptor-elicited-hepatotoxicity
#18
Kelly A Fader, Rance Nault, Mathew P Kirby, Gena Markous, Jason Matthews, Timothy R Zacharewski
Persistent aryl hydrocarbon receptor (AhR) agonists elicit dose-dependent hepatic lipid accumulation, oxidative stress, inflammation, and fibrosis in mice. Iron (Fe) promotes AhR-mediated oxidative stress by catalyzing reactive oxygen species (ROS) production. To further characterize the role of Fe in AhR-mediated hepatotoxicity, male C57BL/6 mice were orally gavaged with sesame oil vehicle or 0.01-30μg/kg 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) every 4days for 28days. Duodenal epithelial and hepatic RNA-Seq data were integrated with hepatic AhR ChIP-Seq, capillary electrophoresis protein measurements, and clinical chemistry analyses...
February 14, 2017: Toxicology and Applied Pharmacology
https://www.readbyqxmd.com/read/28211993/recent-lab-on-chip-developments-for-novel-drug-discovery
#19
REVIEW
Nauman Khalid, Isao Kobayashi, Mitsutoshi Nakajima
Microelectromechanical systems (MEMS) and micro total analysis systems (μTAS) revolutionized the biochemical and electronic industries, and this miniaturization process became a key driver for many markets. Now, it is a driving force for innovations in life sciences, diagnostics, analytical sciences, and chemistry, which are called 'lab-on-a-chip, (LOC)' devices. The use of these devices allows the development of fast, portable, and easy-to-use systems with a high level of functional integration for applications such as point-of-care diagnostics, forensics, the analysis of biomolecules, environmental or food analysis, and drug development...
February 17, 2017: Wiley Interdisciplinary Reviews. Systems Biology and Medicine
https://www.readbyqxmd.com/read/28211697/benchmarking-density-functionals-for-chemical-bonds-of-gold
#20
Kasper Planeta Kepp
Gold plays a major role in nanochemistry, catalysis, and electrochemistry. Accordingly, hundreds of studies apply density functionals to study chemical bonding with gold, yet there is no systematic attempt to assess the accuracy of these methods applied to gold. This paper reports a benchmark against 51 experimental bond enthalpies of AuX systems and seven additional polyatomic and cationic molecules. 12 density functionals were tested, covering meta functionals, hybrids with variable HF exchange, double-hybrid, dispersion-corrected and non-hybrid GGA functionals...
February 17, 2017: Journal of Physical Chemistry. A
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