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https://www.readbyqxmd.com/read/28092834/computational-exploration-of-regioselectivity-and-atmospheric-lifetime-in-no3-initiated-reactions-of-ch3och3-and-ch3och2ch3
#1
Jin-Ting Ye, Feng-Yang Bai, Shao-Qing Shi, Xiu-Mei Pan
The NO3-initiated reactions of CH3OCH3 and CH3OCH2CH3 have been investigated by the BHandHLYP method in conjunction with the 6-311G(d,p) basis set. Thermodynamic and kinetic data are further refined using the comparatively accurate CCSD(T) method. According to the values of reaction enthalpies (ΔHr,298(θ)) and reaction Gibbs free energies (ΔGr,298(θ)) from CH3OCH2CH3 with NO3 system, we find that H-abstraction pathway from the α-CH2 group is more exothermic. It is further confirmed by the calculated CH bond dissociation energy of CH3OCH2CH3 molecule...
January 6, 2017: Journal of Molecular Graphics & Modelling
https://www.readbyqxmd.com/read/28092813/walking-mechanics-for-patellofemoral-pain-subjects-with-similar-self-reported-pain-levels-can-differ-based-upon-neuromuscular-activation
#2
Matthew K Seeley, S Jun Son, Hyunsoo Kim, J Ty Hopkins
Patellofemoral pain (PFP) is often studied on subjects who are classified using only self-reported data. Neuromuscular activation influences movement mechanics for PFP subjects, but is not likely to be self-reported. We compared lower-extremity mechanics, during a common movement (walking), between two subdivisions of a group of PFP subjects that were similar, based on common self-report tools, but different, based on a common objective measure of quadriceps activation. Our intent was to highlight the importance of objectively considering neuromuscular activation when researching PFP movement mechanics...
January 9, 2017: Gait & Posture
https://www.readbyqxmd.com/read/28092786/imaging-thiol-redox-status-in-murine-tumors-in-vivo-with-rapid-scan-electron-paramagnetic-resonance
#3
Boris Epel, Subramanian V Sundramoorthy, Martyna Krzykawska-Serda, Matthew C Maggio, Mark Tseytlin, Gareth R Eaton, Sandra S Eaton, Gerald M Rosen, Joseph P Y Kao, Howard J Halpern
Thiol redox status is an important physiologic parameter that affects the success or failure of cancer treatment. Rapid scan electron paramagnetic resonance (RS EPR) is a novel technique that has shown higher signal-to-noise ratio than conventional continuous-wave EPR in in vitro studies. Here we used RS EPR to acquire rapid three-dimensional images of the thiol redox status of tumors in living mice. This work presents, for the first time, in vivo RS EPR images of the kinetics of the reaction of (2)H,(15)N-substituted disulfide-linked dinitroxide (PxSSPx) spin probe with intracellular glutathione...
December 31, 2016: Journal of Magnetic Resonance
https://www.readbyqxmd.com/read/28092767/effects-of-oil-dispersant-on-ozone-oxidation-of-phenanthrene-and-pyrene-in-marine-water
#4
Yanyan Gong, Dongye Zhao
This work investigated effects of a popular oil dispersant (Corexit EC9500A) on oxidation of phenanthrene and pyrene (two model polycyclic aromatic hydrocarbons) in Gulf coast seawater under simulated atmospheric ozone. The degradation data followed a two-stage pseudo-first order kinetics, a slower initial reaction rate followed by a much faster rate in longer time. The ozonation rate for pyrene was faster than that for phenanthrene. The presence of 18 and 180 mg/L of the dispersant inhibited the first-order degradation rate by 32-80% for phenanthrene, and 51-85% for pyrene...
January 4, 2017: Chemosphere
https://www.readbyqxmd.com/read/28092755/coagulation-flocculation-sequential-with-fenton-or-photo-fenton-processes-as-an-alternative-for-the-industrial-textile-wastewater-treatment
#5
Edison GilPavas, Izabela Dobrosz-Gómez, Miguel Ángel Gómez-García
In this study, the industrial textile wastewater was treated using a chemical-based technique (coagulation-flocculation, C-F) sequential with an advanced oxidation process (AOP: Fenton or Photo-Fenton). During the C-F, Al2(SO4)3 was used as coagulant and its optimal dose was determined using the jar test. The following operational conditions of C-F, maximizing the organic matter removal, were determined: 700 mg/L of Al2(SO4)3 at pH = 9.96. Thus, the C-F allowed to remove 98% of turbidity, 48% of Chemical Oxygen Demand (COD), and let to increase in the BOD5/COD ratio from 0...
January 13, 2017: Journal of Environmental Management
https://www.readbyqxmd.com/read/28092743/stable-isotope-composition-of-mercury-forms-in-flue-gases-from-a-typical-coal-fired-power-plant-inner-mongolia-northern-china
#6
Shunlin Tang, Chaohui Feng, Xinbin Feng, Jianming Zhu, Ruoyu Sun, Huipeng Fan, Lina Wang, Ruiyang Li, Tonghua Mao, Ting Zhou
Mercury forms emitted from coal combustion via air pollution control devices are speculated to carry different Hg isotope signatures. Yet, their Hg isotope composition is still not reported. Here, we present the first onsite Hg isotope data for gaseous elemental Hg (GEM) and gaseous oxidized Hg (GOM) of flue gases from a typical lignite-fired power plant (CFPP). Significant mass dependent fractionation (MDF) and insignificant mass independent fractionation (MIF) are observed between feed coal and coal combustion products...
January 11, 2017: Journal of Hazardous Materials
https://www.readbyqxmd.com/read/28092739/an-emg-driven-biomechanical-model-of-the-canine-cervical-spine
#7
M Alizadeh, G G Knapik, J S Dufour, C Zindl, M J Allen, J Bertran, N Fitzpatrick, W S Marras
Due to the frequency of cervical spine injuries in canines, the purpose of this effort was to develop an EMG-driven dynamic model of the canine cervical spine to assess a biomechanical understanding that enables one to investigate the risk of neck disorders. A canine subject was recruited in this investigation in order to collect subject specific data. Reflective markers and a motion capture system were used for kinematic measurement; surface electrodes were used to record electromyography signals, and with the aid of force plate kinetics were recorded...
December 26, 2016: Journal of Electromyography and Kinesiology
https://www.readbyqxmd.com/read/28092732/enhancement-of-lipid-productivity-by-adopting-multi-stage-continuous-cultivation-strategy-in-nannochloropsis-gaditana
#8
Min-Gyu Sung, Bongsoo Lee, Chul Woong Kim, Kibok Nam, Yong Keun Chang
In the present study, a novel process-based cultivation system was designed to improve lipid productivity of Nannochloropsis gaditana, an oleaginous microalga that has high potential for biofuel production. Specifically, four flat-panel photobioreactors were connected in series, and this system was subjected to continuous chemostat cultivation by feeding fresh medium to the first reactor at dilution rates of 0.028 and 0.056day(-1), which were determined based on Monod kinetics. The results show that the serially connected photobioreactor system achieved 20...
December 30, 2016: Bioresource Technology
https://www.readbyqxmd.com/read/28092705/o-h-activation-by-an-unexpected-ferryl-intermediate-during-catalysis-by-2-hydroxyethylphosphonate-dioxygenase
#9
Spencer C Peck, Chen Wang, Laura M K Dassama, Bo Zhang, Yisong Guo, Lauren J Rajakovich, J Martin Bollinger, Carsten Krebs, Wilfred A van der Donk
Activation of O-H bonds by inorganic metal-oxo complexes has been documented, but no cognate enzymatic process is known. Our mechanistic analysis of 2-hydroxyethylphosphonate dioxygenase (HEPD), which cleaves the C1-C2 bond of its substrate to afford hydroxymethylphosphonate on the biosynthetic pathway to the commercial herbicide phosphinothricin, uncovered an example of such an O-H-bond-cleavage event. Stopped-flow UV-visible absorption and freeze-quench Mössbauer experiments identified a transient iron(IV)-oxo (ferryl) complex...
January 16, 2017: Journal of the American Chemical Society
https://www.readbyqxmd.com/read/28092633/unconventional-superconductivity-in-generalized-hubbard-model-role-of-electron-hole-symmetry-breaking-terms
#10
Marcin M Wysokiński, Jan Kaczmarczyk
We investigate the effect of the electron-hole (e-h) symmetry breaking on d-wave superconductivity induced by non-local effects of correlations in the generalized Hubbard model. The symmetry breaking is introduced in a two-fold manner: by the next-to-nearest neighbor hopping of electrons and by the charge-bond interaction-the off-diagonal term of the Coulomb potential. Both terms lead to a pronounced asymmetry of the superconducting order parameter. The next-to-nearest neighbor hopping enhances superconductivity for h-doping, while diminishes it for e-doping...
January 16, 2017: Journal of Physics. Condensed Matter: An Institute of Physics Journal
https://www.readbyqxmd.com/read/28092604/replication-kinetics-of-neuropathogenic-and-non-neuropathogenic-equine-herpesvirus-type-1-ehv-1-strains-in-primary-murine-neurons-and-ed-cell-line
#11
J Cymerys, A Słońska, J Brzezicka, A Tucholska, A Chmielewska, J Rola, P Malik, M W Bańbura
Equine herpesvirus type 1 (EHV-1) causes respiratory infections, abortion and neurological disorders in horses. Molecular epidemiology studies have demonstrated that a single-point mutation in DNA polymerase gene, resulting in an amino acid variation (N752/D752), is significantly associated with the neuropathogenic potential of EHV-1 strains. The aim of the study was to elucidate if there are any differences between neuropathogenic (EHV-1 26) and non-neuropathogenic (Jan-E and Rac-H) EHV-1 strains in their ability to infect neuronal cells...
December 1, 2016: Polish Journal of Veterinary Sciences
https://www.readbyqxmd.com/read/28092443/kinetics-and-structure-of-a-cold-adapted-hetero-octameric-atp-phosphoribosyltransferase
#12
Rozanne Stroek, Ying Ge, Paul D Talbot, Mateusz K Glok, Klaudia E Bernas, Catherine M Thomson, Eoin R Gould, Magnus S Alphey, Huanting Liu, Gordon J Florence, James H Naismith, Rafael Guimaraes da Silva
ATP-phosphoribosyltransferase (ATPPRT) catalyses the first step in histidine biosynthesis, the condensation of ATP and 5-phospho-α-D-ribosyl-1-pyrophosphate to generate N(1)-(5-phospho-β-D-ribosyl)-ATP and inorganic pyrophosphate. The enzyme is allosterically inhibited by histidine. Two forms of ATPPRT, encoded by the hisG gene, exist in nature, depending on the species. The long form, HisGL, is a single polypeptide chain with catalytic and regulatory domains. The short form, HisGS, lacks a regulatory domain, and cannot bind histidine...
January 16, 2017: Biochemistry
https://www.readbyqxmd.com/read/28092434/3d-probed-lipid-dynamics-in-small-unilamellar-vesicles
#13
Meng-Hsuan Chao, Yen-Ting Lin, Namasivayam Dhenadhayalan, Hsin-Lung Lee, Hsin-Yen Lee, King-Chuen Lin
Single-molecule fluorescence correlation spectroscopy overcomes the resolution barrier of optical microscopy (10≈-20 nm) and is utilized to look into lipid dynamics in small unilamellar vesicles (SUVs; diameter < 100 nm). The fluorescence trajectories of lipid-like tracer 1,1'-dioctadecyl-3,3,3',3'-tetramethylindodicarbocyanine (DiD) in the membrane bilayers are acquired at a single-molecule level. The autocorrelation analysis yields the kinetic information on lipid organization, oxygen transport, and lateral diffusion in SUVs' membrane...
January 16, 2017: Small
https://www.readbyqxmd.com/read/28092433/design-and-analysis-of-localized-dna-hybridization-chain-reactions
#14
Hieu Bui, Vincent Miao, Sudhanshu Garg, Reem Mokhtar, Tianqi Song, John Reif
Theoretical models of localized DNA hybridization reactions on nanoscale substrates indicate potential benefits over conventional DNA hybridization reactions. Recently, a few approaches have been proposed to speed-up DNA hybridization reactions; however, experimental confirmation and quantification of the acceleration factor have been lacking. Here, a system to investigate localized DNA hybridization reactions on a nanoscale substrate is presented. The system consists of six metastable DNA hairpins that are tethered to a long DNA track...
January 16, 2017: Small
https://www.readbyqxmd.com/read/28092159/probe-decomposition-of-methylammonium-lead-iodide-perovskite-in-n2-and-o2-by-in-situ-infrared-spectroscopy
#15
Xiaozhou Yu, Ying Qin, Qing Peng
Packaging methylammonium lead iodide perovskite (MAPbI3) based solar cells with a controlled gaseous atmosphere, such as N2 or dry air, is a promising solution for its application as outdoor photovoltaics. However, the effect of N2 and O2 on the decomposition chemistry and kinetics of MAPbI3 is not well understood yet. With in-situ Fourier transform infrared spectroscopy measurements, we show that the effective activation energy for the degradation of MAPbI3 in N2 is ~ 120 kJ/mol. The decomposition of MAPbI3 is greatly enhanced when MAPbI3 is exposed to O2...
January 16, 2017: Journal of Physical Chemistry. A
https://www.readbyqxmd.com/read/28092154/correlating-the-network-topology-of-oxide-glasses-with-their-chemical-durability
#16
Nerea Mascaraque, Mathieu Bauchy, Morten M Smedskjaer
Glasses gradually dissolve and corrode when they are exposed to aqueous solutions and for many applications it is necessary to understand and predict the kinetics of the glass dissolution. Despite the recent progress in understanding the impact of chemical composition on the dissolution rate, a detailed understanding of the structural and topological origin of chemical durability in solutions of different pH is still largely lacking. Such knowledge would enable the tailoring of glass dissolution kinetics as a function of chemical composition...
January 16, 2017: Journal of Physical Chemistry. B
https://www.readbyqxmd.com/read/28091999/porous-nano-cerium-oxide-wood-chip-biochar-composites-for-aqueous-levofloxacin-removal-and-sorption-mechanism-insights
#17
Shengze Yi, Yuanyuan Sun, Xin Hu, Hongxia Xu, Bin Gao, Jichun Wu
The adsorption removal of levofloxacin (LEV), a widely used fluoroquinolone antibiotic, by using the biochars derived from the pyrolysis of pine wood chip pretreated with cerium trichloride was investigated through batch sorption experiments and multiple characterization techniques. The differences in the basic physicochemical properties between Ce-impregnated biochars and the pristine biochars were confirmed by the analysis of elemental compositions, specific surface areas, energy dispersive spectrometry, X-ray diffraction, and thermo-gravimetry...
January 14, 2017: Environmental Science and Pollution Research International
https://www.readbyqxmd.com/read/28091995/biodegradability-of-fluoxetine-mefenamic-acid-and-metoprolol-using-different-microbial-consortiums
#18
Yolanda Flores Velázquez, Petia Mijaylova Nacheva
The biodegradation of fluoxetine, mefenamic acid, and metoprolol using ammonium-nitrite-oxidizing consortium, nitrite-oxidizing consortium, and heterotrophic biomass was evaluated in batch tests applying different retention times. The ammonium-nitrite-oxidizing consortium presented the highest biodegradation percentages for mefenamic acid and metoprolol, of 85 and 64% respectively. This consortium was also capable to biodegrade 79% of fluoxetine. The heterotrophic consortium showed the highest ability to biodegrade fluoxetine reaching 85%, and it also had a high potential for biodegrading mefenamic acid and metoprolol, of 66 and 58% respectively...
January 14, 2017: Environmental Science and Pollution Research International
https://www.readbyqxmd.com/read/28091811/charge-transfer-dissociation-ctd-mass-spectrometry-of-peptide-cations-study-of-charge-state-effects-and-side-chain-losses
#19
Pengfei Li, Glen P Jackson
1+, 2+, and 3+ precursors of substance P and bradykinin were subjected to helium cation irradiation in a 3D ion trap mass spectrometer. Charge exchange with the helium cations produces a variety of fragment ions, the number and type of which are dependent on the charge state of the precursor ions. For 1+ peptide precursors, fragmentation is generally restricted to C-CO backbone bonds (a and x ions), whereas for 2+ and 3+ peptide precursors, all three backbone bonds (C-CO, C-N, and N-Cα) are cleaved. The type of backbone bond cleavage is indicative of possible dissociation channels involved in CTD process, including high-energy, kinetic-based, and ETD-like pathways...
January 13, 2017: Journal of the American Society for Mass Spectrometry
https://www.readbyqxmd.com/read/28091753/vtst-mt-studies-of-the-catalytic-mechanism-of-c-h-activation-by-transition-metal-complexes-with-cu2-%C3%AE-o2-fe2-%C3%AE-o2-and-fe-iv-o-cores-based-on-dft-potential-energy-surfaces
#20
REVIEW
Yongho Kim, Binh Khanh Mai, Sumin Park
High-valent Cu and Fe species, which are generated from dioxygen activation in metalloenzymes, carry out the functionalization of strong C-H bonds. Understanding the atomic details of the catalytic mechanism has long been one of the main objectives of bioinorganic chemistry. Large H/D kinetic isotope effects (KIEs) were observed in the C-H activation by high-valent non-heme Cu or Fe complexes in enzymes and their synthetic models. The H/D KIE depends significantly on the transition state properties, such as structure, energies, frequencies, and shape of the potential energy surface, when the tunneling effect is large...
January 16, 2017: Journal of Biological Inorganic Chemistry: JBIC
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