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Chemical evolution

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https://www.readbyqxmd.com/read/28231406/fungal-adaptation-to-contemporary-fungicide-applications-the-case-of-botrytis-cinerea-populations-from-champagne-vineyards-france
#1
A-S Walker, V Ravigne, A Rieux, S Ali, F Carpentier, E Fournier
In addition to being one of the most acute problems impeding chemical control of fungal diseases, the evolution of fungicide resistance is an emblematic case of local adaptation to spatially heterogeneous and temporally variable selection pressures. Here we dissected the adaptation of Botrytis cinerea (the causal agent of grey mould) populations on grapes to several fungicides. We carried out a two-year survey (four collection dates) on three treated/untreated pairs of plots from vineyards in Champagne (France), and monitored the frequency of four resistant phenotypes that are unambiguously associated to four distinct genotypes...
February 23, 2017: Molecular Ecology
https://www.readbyqxmd.com/read/28230973/unique-opto-electronic-structure-and-photo-reduction-properties-of-sulfur-doped-lead-chromates-explaining-their-instability-in-paintings
#2
Vanousheh Rahemi, Nasrin Sarmadian, Willemien Anaf, Koen Janssens, Dirk Lamoen, Bart Partoens, Karolien De Wael
Chrome yellow refers to a group of synthetic inorganic pigments that became popular as an artist's material from the second quarter of the 19th century. The color of the pigment, in which the chromate ion acts as a chromophore, is related to its chemical composition (PbCr1-xSxO4, with 0≤x≤0.8) and crystalline structure (monoclinic/orthorhombic). Their shades range from the yellow-orange to the paler yellow tones with increasing sulfate amount. These pigments show remarkable signs of degradation after limited time periods...
February 23, 2017: Analytical Chemistry
https://www.readbyqxmd.com/read/28229154/reactions-of-water-and-c1-molecules-on-carbide-and-metal-modified-carbide-surfaces
#3
REVIEW
Weiming Wan, Brian M Tackett, Jingguang G Chen
The formation of carbides can significantly modify the physical and chemical properties of the parent metals. In the current review, we summarize the general trends in the reactions of water and C1 molecules over transition metal carbide (TMC) and metal-modified TMC surfaces and thin films. Although the primary focus of the current review is on the theoretical and experimental studies of reactions of C1 molecules (CO, CO2, CH3OH, etc.), the reactions of water will also be reviewed because water plays an important role in many of the C1 transformation reactions...
February 23, 2017: Chemical Society Reviews
https://www.readbyqxmd.com/read/28225587/compms2miner-an-automatable-metabolite-identification-visualization-and-data-sharing-r-package-for-high-resolution-lc-ms-datasets
#4
William Matthew Bell Edmands, Lauren M Petrick, Dinesh Kumar Barupal, Augustin Scalbert, Mark Wilson, Jeffrey Wickliffe, Stephen M Rappaport
A long-standing challenge of untargeted metabolomic profiling by ultrahigh performance liquid chromatography-high resolution mass spectrometry (UHPLC-HRMS) is efficient transition from unknown mass spectral features to confident metabolite annotations. The compMS2Miner (Comprehensive MS2 Miner) package was developed in the R language to facilitate rapid, comprehensive feature annotation using a peak-picker-output and MS2 data files as inputs. The number of MS2 spectra that can be collected during a metabolomic profiling experiment far outweigh the amount of time required for pain-staking manual interpretation, therefore a degree of software workflow autonomy is required for broad-scale metabolite annotation...
February 22, 2017: Analytical Chemistry
https://www.readbyqxmd.com/read/28225131/modification-of-n-doped-tio2-photocatalysts-using-noble-metals-pt-pd-a-combined-xps-and-dft-study
#5
K Batalović, N Bundaleski, J Radaković, N Abazović, M Mitrić, R A Silva, M Savić, J Belošević-Čavor, Z Rakočević, C M Rangel
Nitrogen-doped TiO2 (N-TiO2) is considered as one of the most promising materials for various photocatalytic applications, while noble metals Pd and Pt are known as good catalysts for hydrogen evolution. This work focuses on the determination of structural and electronic modifications of N-TiO2, achieved by noble metal deposition at the surface, as a starting indicator for potential applications. We focus on the properties of easily synthesized nanocrystalline nitrogen-doped anatase TiO2, modified by depositing small amounts of Pd (0...
February 22, 2017: Physical Chemistry Chemical Physics: PCCP
https://www.readbyqxmd.com/read/28225110/tuning-the-hydrogen-evolution-activity-of-%C3%AE-mo2c-nanoparticles-via-control-of-their-growth-conditions
#6
Timothy T Yang, Wissam A Saidi
The use of water electrocatalysis for hydrogen production is a promising, sustainable and greenhouse-gas-free process to develop disruptive renewable energy technologies. Transition metal carbides, in particular β-phase Mo2C, are garnering increased attention as hydrogen evolution reaction (HER) catalysts due to their favourable synthesis conditions, stability and high catalytic efficiency. We use a thermodynamic approach in conjunction with density functional theory and a kinetic model of exchange current density to systematically study the HER activity of β-Mo2C under different experimental conditions...
February 22, 2017: Nanoscale
https://www.readbyqxmd.com/read/28224050/exoskeletons-of-bougainvilliidae-and-other-hydroidolina-cnidaria-hydrozoa-structure-and-composition
#7
María A Mendoza-Becerril, José Eduardo A R Marian, Alvaro Esteves Migotto, Antonio Carlos Marques
The exoskeleton is an important source of characters for the taxonomy of Hydroidolina. It originates as epidermal secretions and, among other functions, protects the coenosarc of the polypoid stage. However, comparative studies on the exoskeletal tissue origin, development, chemical, and structural characteristics, as well as its evolution and homology, are few and fragmented. This study compares the structure and composition of the exoskeleton and underlying coenosarc in members of "Anthoathecata" and some Leptothecata, but does so mainly in bougainvilliid polyps histological analyses...
2017: PeerJ
https://www.readbyqxmd.com/read/28222601/energy-related-small-molecule-activation-reactions-oxygen-reduction-and-hydrogen-and-oxygen-evolution-reactions-catalyzed-by-porphyrin-and-corrole-based-systems
#8
Wei Zhang, Wenzhen Lai, Rui Cao
Globally increasing energy demands and environmental concerns related to the use of fossil fuels have stimulated extensive research to identify new energy systems and economies that are sustainable, clean, low cost, and environmentally benign. Hydrogen generation from solar-driven water splitting is a promising strategy to store solar energy in chemical bonds. The subsequent combustion of hydrogen in fuel cells produces electric energy, and the only exhaust is water. These two reactions compose an ideal process to provide clean and sustainable energy...
February 22, 2017: Chemical Reviews
https://www.readbyqxmd.com/read/28218294/correlated-electron-nuclear-dynamics-in-above-threshold-multiphoton-ionization-of-asymmetric-molecule
#9
Zhuo Wang, Min Li, Yueming Zhou, Pengfei Lan, Peixiang Lu
The partition of the photon energy into the subsystems of molecules determines many photon-induced chemical and physical dynamics in laser-molecule interactions. The electron-nuclear energy sharing from multiphoton ionization of molecules has been used to uncover the correlated dynamics of the electron and fragments. However, most previous studies focus on symmetric molecules. Here we study the electron-nuclear energy sharing in strong-field photoionization of HeH(2+) by solving the one-dimensional time-dependent Schrödinger equation (TDSE)...
February 20, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28216663/the-importance-of-pollen-chemistry-in-evolutionary-host-shifts-of-bees
#10
Maryse Vanderplanck, Nicolas J Vereecken, Laurent Grumiau, Fabiana Esposito, Georges Lognay, Ruddy Wattiez, Denis Michez
Although bee-plant associations are generally maintained through speciation processes, host shifts have occurred during evolution. Understanding shifts between both phylogenetically and morphologically unrelated plants (i.e., host-saltation) is especially important since they could have been key processes in the origin and radiation of bees. Probably far from being a random process, such host-saltation might be driven by hidden constraints associated with plant traits. We selected two clades of oligolectic bees (i...
February 20, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28216567/wine-flavonoids-in-health-and-disease-prevention
#11
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/28216419/seasonal-cycle-of-inbreeding-and-recombination-of-the-parasitic-mite-varroa-destructor-in-honeybee-colonies-and-its-implications-for-the-selection-of-acaricide-resistance
#12
Alexis L Beaurepaire, Klemens J Krieger, Robin F A Moritz
Varroa destructor is the most devastating parasite of the Western honeybee, Apis mellifera. In the light of the arm race opposing the host and its parasite, the population dynamics and genetic diversity of these organisms are key parameters. However, the life cycle of V. destructor is characterized by extreme inbreeding due to full sibling mating in the host brood cells. We here present an equation reflecting the evolution of inbreeding in such a clonal system, and compare our predictions with empirical data based on the analysis of seven microsatellite markers...
February 16, 2017: Infection, Genetics and Evolution
https://www.readbyqxmd.com/read/28215320/marine-enzymes-in-cancer-a-new-paradigm
#13
R H Prabhu, K S Bhise, V B Patravale
Over the last decades, the vast chemical and biodiversity of marine environment has been identified as an important source of new anticancer drugs. The evolution of marine life is a result of competition among microorganisms for space and nutrients in the marine environment, which drives marine microorganisms to generate diverse enzyme systems with unique properties to adapt to harsh conditions of ocean. Therefore, marine-derived sources offer novel enzymes endowed with extraordinary properties. Recent advances in cancer therapy have facilitated enzyme therapy as a promising tool...
2017: Advances in Food and Nutrition Research
https://www.readbyqxmd.com/read/28213793/automation-of-peak-tracking-analysis-of-stepwise-perturbed-nmr-spectra
#14
Tommaso Banelli, Marco Vuano, Federico Fogolari, Andrea Fusiello, Gennaro Esposito, Alessandra Corazza
We describe a new algorithmic approach able to automatically pick and track the NMR resonances of a large number of 2D NMR spectra acquired during a stepwise variation of a physical parameter. The method has been named Trace in Track (TINT), referring to the idea that a gaussian decomposition traces peaks within the tracks recognised through 3D mathematical morphology. It is capable of determining the evolution of the chemical shifts, intensity and linewidths of each tracked peak.The performances obtained in term of track reconstruction and correct assignment on realistic synthetic spectra were high above 90% when a noise level similar to that of experimental data were considered...
February 17, 2017: Journal of Biomolecular NMR
https://www.readbyqxmd.com/read/28212031/bond-activation-and-hydrogen-evolution-from-water-through-reactions-with-m3s4-m-mo-w-and-w3s3-anionic-clusters
#15
Corrine A Kumar, Arjun Saha, Krishnan Raghavachari
Transition metal sulfides (TMS) are being investigated with increased frequency because of their ability to efficiently catalyze the hydrogen evolution reaction. We have studied the trimetallic TMS cluster ions, Mo3S4(-), W3S4(-), and W3S3(-), and probed their efficiency for bond activation and hydrogen evolution from water. These clusters have geometries that are related to the edge sites on bulk MoS2 surfaces that are known to play a role in hydrogen evolution. Using density functional theory, the electronic structures of these clusters and their chemical reactivity with water have been investigated...
February 17, 2017: Journal of Physical Chemistry. A
https://www.readbyqxmd.com/read/28209339/vitamin-e-stabilized-highly-crosslinked-polyethylenes-the-role-and-effectiveness-in-total-hip-arthroplasty
#16
Kengo Yamamoto, Toshiyuki Tateiwa, Yasuhito Takahashi
Morphology and design of ultra-high molecular weight polyethylene (UHMWPE or simply PE) acetabular components used in total hip arthroplasty (THA) have been evolving for more than half a century. Since the late-1990s, there were two major technological innovations in PE emerged from necessity to overcome the wear-induced periprosthetic osteolysis, i.e., the development of highly crosslinked PEs (HXLPEs). There are many literature reporting that radiation crosslinked and remelted/annealed (first-generation) HXLPEs markedly reduced the incidence of osteolysis and aseptic loosening...
February 10, 2017: Journal of Orthopaedic Science: Official Journal of the Japanese Orthopaedic Association
https://www.readbyqxmd.com/read/28209026/on-demand-fabrication-of-si-sio2-nanowire-arrays-by-nanosphere-lithography-and-subsequent-thermal-oxidation
#17
Huaxiang Cao, Xinhua Li, Bukang Zhou, Tao Chen, Tongfei Shi, Jianqiang Zheng, Guangqiang Liu, Yuqi Wang
We demonstrate the fabrication of the large-area arrays of vertically aligned Si/SiO2 nanowires with full tunability of the geometry of the single nanowires by the metal-assisted chemical etching technique and the following thermal oxidation process. To fabricate the geometry controllable Si/SiO2 nanowire (NW) arrays, two critical issues relating with the size control of polystyrene reduction and oxide thickness evolution are investigated. Through analyzing the morphology evolutions of polystyrene particles, we give a quantitative description on the diameter variations of polystyrene particles with the etching time of plasma etching...
December 2017: Nanoscale Research Letters
https://www.readbyqxmd.com/read/28208324/adsorption-induced-shape-transitions-in-bistable-nanopores-with-atomically-thin-walls
#18
Oleg E Shklyaev, Milton W Cole, Vincent H Crespi
Atomically thin cylindrical nanopores can change shape in response to physically adsorbed gas inside. Coupled to a gas reservoir, an initially collapsed pore can expand to allow the adsorbed gas to form concentric shells on the inner part of the pore, driven by adsorption energetics, not gas pressure. A lattice gas model describes the evolution of the nanotube pore shape and absorbed gas as a function of gas chemical potential at zero temperature. We found that narrow-enough tubes are always expanded and gas inside adsorbs in sequences of concentric shells as the gas chemical potential increases...
January 2017: Physical Review. E
https://www.readbyqxmd.com/read/28207240/interfaces-in-heterogeneous-catalysts-advancing-mechanistic-understanding-through-atomic-scale-measurements
#19
Wenpei Gao, Zachary D Hood, Miaofang Chi
Developing novel catalysts with high efficiency and selectivity is critical for enabling future clean energy conversion technologies. Interfaces in catalyst systems have long been considered the most critical factor in controlling catalytic reaction mechanisms. Interfaces include not only the catalyst surface but also interfaces within catalyst particles and those formed by constructing heterogeneous catalysts. The atomic and electronic structures of catalytic surfaces govern the kinetics of binding and release of reactant molecules from surface atoms...
February 16, 2017: Accounts of Chemical Research
https://www.readbyqxmd.com/read/28205437/surface-and-interface-engineering-of-noble-metal-free-electrocatalysts-for-efficient-energy-conversion-processes
#20
Yun Pei Zhu, Chunxian Guo, Yao Zheng, Shi-Zhang Qiao
Developing cost-effective and high-performance electrocatalysts for renewable energy conversion and storage is motivated by increasing concerns regarding global energy security and creating sustainable technologies dependent on inexpensive and abundant resources. Recent achievements in the design and synthesis of efficient non-precious-metal and even non-metal electrocatalysts make the replacement of noble metal counterparts for the hydrogen evolution reaction (HER), oxygen evolution reaction (OER), and oxygen reduction reaction (ORR) with earth-abundant elements, for example, C, N, Fe, Mn, and Co, a realistic possibility...
February 16, 2017: Accounts of Chemical Research
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