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https://www.readbyqxmd.com/read/29145130/photophysical-and-photochemical-insights-into-the-photodegradation-of-sulfapyridine-in-water-a-joint-experimental-and-theoretical-study
#1
Heming Zhang, Xiaoxuan Wei, Xuedan Song, Shaheen Shah, Jingwen Chen, Jianhui Liu, Ce Hao, Zhongfang Chen
For organic pollutants, photodegradation, as a major abiotic elimination process and of great importance to the environmental fate and risk, involves rather complicated physical and chemical processes of excited molecules. Herein, we systematically studied the photophysical and photochemical processes of a widely used antibiotic, namely sulfapyridine. By means of density functional theory (DFT) computations, we examined the rate constants and the competition of both photophysical and photochemical processes, elucidated the photochemical reaction mechanism, calculated reaction quantum yield (Φ) based on both photophysical and photochemical processes, and subsequently estimated the photodegradation rate constant...
October 7, 2017: Chemosphere
https://www.readbyqxmd.com/read/29145059/binding-of-naringin-and-naringenin-with-hen-egg-white-lysozyme-a-spectroscopic-investigation-and-molecular-docking-study
#2
Sourav Das, Pooja Ghosh, Sudipta Koley, Atanu Singha Roy
The interactions of naringenin (NG) and naringin (NR) with Hen Egg White Lysozyme (HEWL) in aqueous medium have been investigated using UV-vis spectroscopy, steady-state fluorescence, circular dichroism (CD), Fourier Transform infrared spectroscopy (FT-IR) and molecular docking analyses. Both NG and NR can quench the intrinsic fluorescence of HEWL via static quenching mechanism. At 300K, the value of binding constant (Kb) of HEWL-NG complex (5.596±0.063×10(4)M(-1)) was found to be greater than that of HEWL-NR complex (3...
November 8, 2017: Spectrochimica Acta. Part A, Molecular and Biomolecular Spectroscopy
https://www.readbyqxmd.com/read/29144997/examination-of-a-therapeutic-recreation-based-clinical-placement-for-undergraduate-nursing-students-a-self-determined-perspective
#3
Dana Perlman, Ellie Taylor, Lorna Moxham, Susan Sumskis, Christopher Patterson, Renee Brighton, Tim Heffernan
Nursing students across the globe are expected to undertake clinical placements. To date, there have been no studies that have examined the potential educational benefits for undergraduate nursing students engaged in a mental health clinical placement grounded in self-determination theory. The present study examined the experiences of undergraduate students engaged in a mental health clinical placement termed Recovery Camp. An ethnographic methodology within a case study approach was used. The researchers were immersed in the clinical placement, which took place at a YMCA camp facility...
November 10, 2017: Nurse Education in Practice
https://www.readbyqxmd.com/read/29144567/reliable-recognition-of-lying-sitting-and-standing-with-a-hip-worn-accelerometer
#4
Henri Vähä-Ypyä, Pauliina Husu, Jaana Suni, Tommi Vasankari, Harri Sievänen
Hip-worn accelerometers are widely used to estimate physical activity (PA), but the accuracy of acceleration-threshold based analysis is compromised when it comes to identifying stationary and sedentary behaviors, let alone classifying body postures into lying, sitting or standing. The purpose of this study was to devise a novel method for accurate classification of body posture using triaxial data from hip-worn accelerometer and to evaluate its performance in free-living conditions against a thigh-worn accelerometer...
November 16, 2017: Scandinavian Journal of Medicine & Science in Sports
https://www.readbyqxmd.com/read/29144389/effects-of-infrared-optical-trapping-on-saccharomyces-cerevisiae-in-a-microfluidic-system
#5
Zdeněk Pilát, Alexandr Jonáš, Jan Ježek, Pavel Zemánek
Baker's yeast (Saccharomyces cerevisiae) represents a very popular single-celled eukaryotic model organism which has been studied extensively by various methods and whose genome has been completely sequenced. It was also among the first living organisms that were manipulated by optical tweezers and it is currently a frequent subject of optical micromanipulation experiments. We built a microfluidic system for optical trapping experiments with individual cells and used it for the assessment of cell tolerance to phototoxic stress...
November 16, 2017: Sensors
https://www.readbyqxmd.com/read/29143840/nonaffine-deformation-and-tunable-yielding-of-colloidal-assemblies-at-the-air-water-interface
#6
Armando Maestro, Alessio Zaccone
Silica nanoparticles trapped at the air-water interface form a 2D solid state with amorphous order. We propose a theoretical model to describe how this solid-like state deforms under a shear strain ramp up to and beyond a yielding point which leads to plastic flow. The model accounts for all the particle-level and many-body physics of the system: nonaffine displacements, local connectivity and its evolution in terms of cage-breaking, and interparticle interactions mediated by the particle chemistry and colloidal forces...
November 16, 2017: Nanoscale
https://www.readbyqxmd.com/read/29143839/real-time-observation-of-the-photoionization-induced-water-rearrangement-dynamics-in-the-5-hydroxyindole-water-cluster-by-time-resolved-ir-spectroscopy
#7
Mitsuhiko Miyazaki, Ayumi Naito, Takamasa Ikeda, Johanna Klyne, Kenji Sakota, Hiroshi Sekiya, Otto Dopfer, Masaaki Fujii
Solvation plays an essential role in controlling the mechanism and dynamics of chemical reactions in solution. The present study reveals that changes in the local solute-solvent interaction have a great impact on the timescale of solvent rearrangement dynamics. Time-resolved IR spectroscopy has been applied to a hydration rearrangement reaction in the monohydrated 5-hydroxyindole-water cluster induced by photoionization of the solute molecule. The water molecule changes the stable hydration site from the indolic NH site to the substituent OH site, both of which provide a strongly attractive potential for hydration...
November 16, 2017: Physical Chemistry Chemical Physics: PCCP
https://www.readbyqxmd.com/read/29143383/who-performs-colonoscopy-workforce-trends-over-space-and-time
#8
Jan M Eberth, Michele J Josey, Lee R Mobley, Davidson O Nicholas, Donna B Jeffe, Cassie Odahowski, Janice C Probst, Mario Schootman
PURPOSE: With the increased availability of colonoscopy to average risk persons due to insurance coverage benefit changes, we sought to identify changes in the colonoscopy workforce. We used outpatient discharge records from South Carolina between 2001 and 2010 to examine shifts over time and in urban versus rural areas in the types of medical providers who perform colonoscopy, and the practice settings in which they occur, and to explore variation in colonoscopy volume across facility and provider types...
November 16, 2017: Journal of Rural Health
https://www.readbyqxmd.com/read/29143152/electrochemical-and-theoretical-studies-of-the-interactions-of-a-pyridyl-based-corrosion-inhibitor-with-iron-clusters-fe15-fe30-fe45-and-fe60
#9
Julian Cruz-Borbolla, Esteban Garcia-Ochoa, Jayanthi Narayanan, Pablo Maldonado-Rivas, Thangarasu Pandiyan, José M Vásquez-Pérez
The capacity of 2,6-bis[((2-pyridylmethyl)oxy)methyl)]pyridine (BPMMP) to inhibit the corrosion of mild carbon steel in HCl was analyzed. In a polarization study, both the cathodic and anodic currents were appreciably decreased in the presence of BPMMP, suggesting that this ligand is effective at inhibiting corrosion at the metal surface. This conclusion is consistent with the results of impedance analysis, where only one time constant corresponding to one depressed capacitive loop was detected, and the diameter of the impedance plot was directly related to the concentration of BPMMP...
November 15, 2017: Journal of Molecular Modeling
https://www.readbyqxmd.com/read/29143132/thermostable-and-highly-specific-l-aspartate-oxidase-from-thermococcus-litoralis-dsm-5473-cloning-overexpression-and-enzymological-properties
#10
Tsubasa Washio, Tadao Oikawa
We successfully expressed the L-aspartate oxidase homolog gene (accession no: OCC_06611) of Thermococcus litoralis DSM 5473 in the soluble fraction of Escherichia coli BL21 (DE3) using a pET21b vector with 6X His tag at its C-terminus. The gene product (Tl-LASPO) showed L-aspartate oxidase activity in the presence of FAD in vitro, and this report is the first that details an L-aspartate oxidase derived from a Thermococcus species. The homologs of Tl-LASPO existed mainly in archaea, especially in the genus of Thermococcus, Pyrococcus, Sulfolobus, and Halobacteria...
November 15, 2017: Extremophiles: Life Under Extreme Conditions
https://www.readbyqxmd.com/read/29143004/adsorption-parameters-and-phase-behaviour-of-non-ionic-surfactants-at-liquid-interfaces
#11
Radomir Iliev Slavchov, Ivan Boyanov Ivanov
A reasonable adsorption model is one that allows all adsorption parameters (adsorption constant, hard-disc area α, attraction parameter β) of a surfactant at a liquid interface to be predicted accurately as a function of the molecular structure and medium conditions. However, the established adsorption models of van der Waals and Frumkin lead to inconsistencies, such as negative β at water|oil, α significantly larger than the crystallographic area of the molecule, and phase behaviour that contradicts the experimental observations...
November 16, 2017: Soft Matter
https://www.readbyqxmd.com/read/29141422/coverage-dependent-molecular-assembly-of-anthraquinone-on-au-111
#12
Andrew S DeLoach, Brad R Conrad, T L Einstein, Daniel B Dougherty
A scanning tunneling microscopy study of anthraquinone (AQ) on the Au(111) surface shows that the molecules self-assemble into several structures depending on the local surface coverage. At high coverages, a close-packed saturated monolayer is observed, while at low coverages, mobile surface molecules coexist with stable chiral hexamer clusters. At intermediate coverages, a disordered 2D porous network interlinking close-packed islands is observed in contrast to the giant honeycomb networks observed for the same molecule on Cu(111)...
November 14, 2017: Journal of Chemical Physics
https://www.readbyqxmd.com/read/29141152/tm-values-and-unfolded-fraction-can-predict-aggregation-rates-for-gcsf-variant-formulations-but-not-under-predominantly-native-conditions
#13
Mathew J Robinson, Paul Matejtschuk, Adrian F Bristow, Paul A Dalby
Protein engineering and formulation optimisation strategies can be taken to minimise protein aggregation in the biopharmaceutical industry. Short-term stability measures such as the mid-point transition temperature (Tm) for global unfolding provide convenient surrogates for longer-term (eg 2-year) degradation kinetics, with which to optimise formulations on practical time-scales. While successful in some cases, their limitations have not been fully evaluated or understood. Tm values are known to correlate with chemical degradation kinetics for wild-type granulocyte colony stimulating factor (GCSF) at pH 4-5...
November 15, 2017: Molecular Pharmaceutics
https://www.readbyqxmd.com/read/29141118/pbs-cds-core-shell-qds-suppress-charge-transfer-and-enhance-triplet-transfer
#14
Zhiyuan Huang, Zihao Xu, Melika Mahboub, Xin Li, Jordan Taylor, Hill Harman, Tianquan Lian, MingLee Tang
Here, we observe that a sub-monolayer CdS shell on PbS quantum dots (QDs) enhances triplet energy transfer (TET) by suppressing competitive charge transfer from QDs to molecules. The CdS shell increases the linear photon upconversion quantum yield (QY) from 3.5% for PbS QDs to 5.0% for PbS/CdS QDs when functionalized with a tetracene acceptor, 5-CT. While transient absorption spectroscopy reveals that both PbS and PbS/CdS QDs show the formation of the 5-CT triplet (with rate constants of 5.91 ±0.60 ns-1 and 1...
November 15, 2017: Angewandte Chemie
https://www.readbyqxmd.com/read/29140746/inactivation-kinetics-of-pathogens-during-thermal-processing-in-acidified-broth-and-tomato-pur%C3%A3-e-ph-4-5
#15
Evann L Dufort, Jonathan Sogin, Mark R Etzel, Barbara H Ingham
Thermal inactivation kinetics for single strains of Shiga toxin-producing Escherichia coli (STEC), Listeria monocytogenes, and Salmonella enterica were measured in acidified tryptic soy broth (TSB; pH 4.5) heated at 54°C. Inactivation curves also were measured for single-pathogen five-strain cocktails of E. coli O157:H7, L. monocytogenes, and S. enterica heated in tomato purée (pH 4.5) at 52, 54, 56, and 58°C. Inactivation curves were fit using log-linear and nonlinear (Weibull) models. The Weibull model yields the time for a 5-log reduction (t*) and a curve shape parameter (β)...
November 15, 2017: Journal of Food Protection
https://www.readbyqxmd.com/read/29140701/the-hydrophobe-challenge-a-joint-experimental-and-computational-study-on-the-host-guest-binding-of-hydrocarbons-to-cucurbiturils-allowing-explicit-evaluation-of-guest-hydration-free-energy-contributions
#16
Khaleel I Assaf, Mara Florea, Jens Antony, Niel M Henriksen, Jian Yin, Andreas Hansen, Zheng-Wang Qu, Rebecca Sure, Dieter Klapstein, Michael K Gilson, Stefan Grimme, Werner M Nau
The host-guest complexation of hydrocarbons (22 guest molecules) with cucurbit[7]uril was investigated in aqueous solution by using the indicator displacement strategy. The binding constants (10(3)-10(9) M(-1)) increased with guest size, pointing to the hydrophobic effect and dispersion interactions as driving forces. The measured affinities provide unique benchmark data for the binding of neutral guest molecules. Consequently, a computational blind challenge, the HYDROPHOBE challenge, was conducted in order to allow a comparison with state-of-the-art computational methods for predicting host-guest affinity constants...
November 15, 2017: Journal of Physical Chemistry. B
https://www.readbyqxmd.com/read/29140293/the-trends-in-cardiovascular-diseases-and-respiratory-diseases-mortality-in-urban-and-rural-china-1990-2015
#17
Weiwei Sun, Yun Zhou, Zhuang Zhang, Limin Cao, Weihong Chen
With the rapid development of the economy over the past 20 years, the mortality rates from cardiovascular diseases (CVDs) and respiratory diseases (RDs) have changed in China. This study aimed to analyze the trends of mortality rates and years of life lost (YLLs) from CVDs and RDs in the rural and urban population from 1990 to 2015. Using data from Chinese yearbooks, joinpoint regression analysis was employed to estimate the annual percent change (APC) of mortality rates from CVDs and RDs. YLLs due to CVDs and RDs were calculated by a standard method, adopting recommended standard life expectancy at birth values of 80 years for men and 82...
November 15, 2017: International Journal of Environmental Research and Public Health
https://www.readbyqxmd.com/read/29140088/symmetrical-and-nonsymmetrical-meso-meso-directly-linked-hydroporphyrin-dyads-synthesis-and-photochemical-properties
#18
Nopondo N Esemoto, Andrius Satraitis, Linda Wiratan, Marcin Ptaszek
A series of a rigid meso-meso directly linked chlorin-chlorin, chlorin-bacteriochlorin, and bacteriochlorin-bacteriochlorin dyads, including free bases as well as Zn(II), Pd(II), and Cu(II) complexes, has been synthesized, and their absorption, emission, singlet oxygen ((1)O2) photosensitization, and electronic properties have been examined. Marked bathochromic shifts of the long-wavelength Qy absorption band and increase in fluorescence quantum yields in dyads, in comparison to the corresponding monomers, are observed...
November 15, 2017: Inorganic Chemistry
https://www.readbyqxmd.com/read/29139530/when-droplets-become-stars-charged-dielectric-droplets-beyond-the-rayleigh-limit
#19
Myong In Oh, Anatoly Malevanets, Maxim Paliy, Daan Frenkel, Styliani Consta
When a nano-drop comprising a single spherical central ion and dielectric solvent is charged above a well-defined threshold, it acquires a stable star morphology. In contrast, conducting droplets, will undergo fission. Here we report combined atomistic molecular dynamics and continuum modelling study of star formation of droplets that contain a highly charged ion. We assume that in the continuum model the dielectric response is linear. In this linear continuum model, which is an extension of Rayleigh model, the energy of the drop is comprised of terms analogous to those in Rayleigh model, which are surface energy and electrostatic energy of dielectric droplet charged by a central point charge...
November 15, 2017: Soft Matter
https://www.readbyqxmd.com/read/29138240/kinetics-of-h2o2-driven-degradation-of-chitin-by-a-bacterial-lytic-polysaccharide-monooxygenase
#20
Silja Kuusk, Bastien Bissaro, Piret Kuusk, Zarah Forsberg, Vincent G H Eijsink, Morten Sørlie, Priit Väljamäe
Lytic polysaccharide monooxygenases (LPMOs) catalyze the oxidative cleavage of glycosidic bonds in recalcitrant polysaccharides, such as cellulose and chitin, and are of interest in biotechnological utilization of these abundant biomaterials. It has recently been shown that LPMOs can use H2O2, instead of O2, as a co-substrate. This peroxygenase-like reaction by a mono-copper enzyme is unprecedented in nature and opens new avenues in chemistry and enzymology. Here, we provide the first detailed kinetic characterization of chitin degradation by the bacterial LPMO chitin-binding protein CBP21 using H2O2 as co-substrate...
November 14, 2017: Journal of Biological Chemistry
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