bluuebunny/crossref_metadata_2025_split huggingface dataset:
State‐Resolved Stereodynamics of an Insertion Reaction O(1D2) + H2(v = 0, j) → OH(X2Πi; v′, N′, f′) + H
Authors: Alexander Andrew J. , Javier Aoiz F. , Brouard Mark , Short Justin , Simons John P. 
Published: November 2013

AbstractThe product state‐resolved stereodynamics of the reaction of O(1D2) with H2 have been studied at 300 K at a mean collision energy of ca. 12 kJ mol−1, using polarized, Doppler‐resolved laser‐induced fluorescence to probe the scattered products, OH(X2Πi; v′ = 0, N′, f′), and polarized photodissociation of N2O to provide the reagent O(1D2) atoms. Product state‐resolved differential cross sections, rotational polarizations, and excitation functions are in very good qualitative agreement with the results of quasi‐classical trajectory (QCT) calculations, conducted on the Schinke‐Lester, SL1 ab initio potential energy surface (PES) for the ground electronic state of the collision complex. The experimental and computational results are compared with those obtained in a complementary study of the reaction of O(1D2) with CH4 and remarkable parallels have been exposed. The linear and angular momentum vector correlations are all consistent with an “insertion” mechanism, proceeding over an attractive PES, which presents no entrance barrier.
Coadsorption of CO and O on Ru(0001): A Structural Analysis by Density Functional Theory
Authors: Stampfl Catherine , Scheffler Matthias 
Published: November 2013

AbstractKnowledge of the atomic geometry of a surface is a prerequisite for any detailed understanding of the surface's electronic structure and chemical properties. Previous studies have convincingly demonstrated that density functional theory (DFT) yields accurate surface atomic geometries and that reliable predictions concerning stable and metastable phases can be made on the basis of the calculated energetics. In the present work, we use DFT to investigate the atomic structure of four ordered coadsorbate phases of carbon monoxide and oxygen on Ru (0001). All of the structures have a (2 × 2) periodicity with differing concentrations of CO molecules and O atoms. For two of these phases dynamical low‐energy electron diffraction (LEED) intensity analyses have been performed, and the agreement between our DFT‐ and the LEED‐determined structures is found to be very good. We predict the atomic geometry of the third phase, for which no structural determination based on experiments has been made to date. We also predict the stability of a new ordered mixed phase.
PRISM: Piecewise Reusable Implementation of Solution Mapping. An Economical Strategy for Chemical Kinetics
Authors: Tonse Shaheen R. , Moriarty Nigel W. , Brown Nancy J. , Frenklach Michael 
Published: November 2013

AbstractIn a chemical kinetics calculation, a solution‐mapping procedure is applied to parametrize the solution of the initial‐value ordinary differential equation system as a set of algebraic polynomial equations. To increase the accuracy, the parametrization is done piecewise, dividing the multidimensional chemical composition space into hypercubes and constructing polynomials for each hypercube. A differential equation solver is used to provide the solution at selected points throughout a hypercube, and from these solutions the polynomial coefficients are determined. Factorial design methods are used to reduce the required number of computed points. The polynomial coefficients for each hypercube are stored in a data structure for subsequent reuse, since over the duration of a flame simulation it is likely that a particular set of concentrations and temperature will occur repeatedly at different times and positions.The method is applied to H2–air combustion using an 8‐species reaction set. After N2 is added as an inert species and enthalpy is considered, this results in a 10‐dimensional chemical composition space. To add the capability of using a variable time‐step, time‐step is added as an additional dimension, making an 11‐dimensional space. Reactive fluid dynamical simulations of a 1‐D laminar premixed flame and a 2‐D turbulent non‐premixed jet are performed. The results are compared to identical control runs which use an ordinary differential equation solver to calculate the chemical kinetic rate equations. The resulting accuracy is very good, and a factor of 10 increase in computational efficiency is attained.
Hydrogen Bond Compression during Triple Proton Transfer in Crystalline Pyrazoles. A Dynamic 15N NMR Study
Authors: Klein Oliver , Bonvehi Maria Minguet , Aguilar‐Parrilla Francisco , Jagerovic Nadine , Elguero José , Limbach Hans‐Heinrich 
Published: November 2013

AbstractUsing dynamic solid state 15N CPMAS NMR spectroscopy (CP ≡ cross polarization, MAS ≡ magic‐angle spinning), the kinetics of degenerate intermolecular triple proton and deuteron transfers in the cyclic trimers of 15N‐labeled polycrystalline 4‐nitropyrazole (4NO2P) and 4‐bromopyrazole (4BrP) have been studied as a function of temperature and are compared to the kinetics of triple proton transfer in bulk solid 3,5‐dimethylpyrazole (DMP) studied previously. The results show that the transfer kinetics in the new trimers are much faster than in DMP. However, the kinetic HHH/HHD/HDD/DDD isotope effects of 4NO2P are similar to those of DMP. These effects indicate a single barrier for the triple proton transfers where all three protons lose zero‐point energy in the transition state, as expected for a structure with three compressed hydrogen bonds. At low temperatures, strong deviations from an Arrhenius‐behavior are observed which are described in terms of a modified Bell tunneling model and a concerted proton motion. The barrier for the triple proton transfer in 4NO2P and 4BrP is substantially smaller than in DMP. As there is no correlation with the electronic properties of the substituents, we assign this finding to steric effects where the bulky methyl groups of DMP in the 3‐ and 5‐positions hinder the hydrogen bond compression, in contrast to 4NO2P and 4BrP exhibiting substitutents in the 4‐position. These results lead to a minimum energy pathway of the proton transfer following in the absence of steric hindering the hydrogen bond correlation line q1 = f(q2), established previously, where q1 represents the deviation of the proton from the hydrogen bond center and q2 the N…N distance. Tunneling occurs at constant N…N distances.
An Electrophysiological Comparison of Voltage‐Gated Proton Channels, Other Ion Channels, and Other Proton Channels
Authors: Decoursey Thomas E. , Cherny Vladimir V. 
Published: November 2013

AbstractVoltage‐gated proton selective channels occupy an ill‐defined region between “normal” ion channels and a variety of proton‐conducting pathways inside proteins, including, but not limited to, membrane‐bound proteins. Voltage‐gated H+ channels closely resemble other voltage‐gated ion channels in their voltage‐ and time‐dependent gating, but differ in their extreme selectivity, their miniscule single‐channel conductance, and the high activation enthalpy for conduction. Furthermore, in contrast with the “multiple occupancy” hypothesized to account for aspects of permeation through other ion channels, it seems unlikely that H+ channels can be occupied by more than one proton at a time. Voltage‐gated H+ channels functionally resemble other proton‐conducting pathways in proteins, but until their structure has been determined, this similarity will remain speculative. The present restriction to functional measurements is less of a handicap than might be expected—the history of ion channel research shows that deductions based on electrophysiological measurements often closely predict the eventually determined structure. Existing evidence supports the idea that protons permeate the membrane through voltage‐gated H+ channels by hopping across a hydrogen‐bonded chain that consists of at least some amino acid side groups in addition to water molecules.
Terminal sterilization of alginate hydrogels: Efficacy and impact on mechanical properties
Authors: Stoppel Whitney L. , White Joseph C. , Horava Sarena D. , Henry Anna C. , Roberts Susan C. , Bhatia Surita R. 
Published: November 2013

AbstractTerminal, or postprocessing, sterilization of composite biomaterials is crucial for their use in wound healing and tissue‐engineered devices. Recent research has focused on optimizing traditional biomaterial formulations to create better products for commercial and academic use which incorporate hydrophobic compounds or secondary gel networks. To use a hydrogel in a clinical setting, terminal sterilization is necessary to ensure patient safety. Lyophilization, gamma‐irradiation, and ethylene oxide treatment all have negative consequences when applied to alginate scaffolds for clinical use. Here, we aim to find alternative terminal sterilization methods for alginate and alginate‐based composite hydrogels which maintain the structure of composite alginate networks for use in biomedical applications. A thorough investigation of the effect of common sterilization methods on swollen alginate‐based hydrogels has not been reported and therefore, this work examines autoclaving, ethanol washing, and ultraviolet light as sterilization techniques for alginate and alginate/Pluronic® F68 composite hydrogels. Preservation of structural integrity is evaluated using shear rheology and analysis of water retention, and efficacy of sterilization is determined via bacterial persistence within the hydrogel. Results indicate that ethanol sterilization is the best method of those investigated because ethanol washing results in minimal effects on mechanical properties and water retention and eliminates bacterial persistence. Furthermore, this study suggests that ethanol treatment is an efficacious method for terminally sterilizing interpenetrating networks or other composite hydrogel systems. © 2013 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 102B: 877–884, 2014.
From unicuspid to quadricuspid: Influence of aortic valve morphology on aortic three‐dimensional hemodynamics
Authors: Entezari Pegah , Schnell Susanne , Mahadevia Riti , Malaisrie Chris , McCarthy Patrick , Mendelson Marla , Collins Jeremy , Carr James C. , Markl Michael , Barker Alex J. 
Published: November 2013

PurposeTo assess the impact of aortic valve morphology on aortic hemodynamics between normal tricuspid and congenitally anomalous aortic valves ranging from unicuspid to quadricuspid morphology.Materials and MethodsAortic three‐dimensional (3D) blood flow was evaluated by 4D flow MRI in 14 healthy volunteers with normal trileaflet valves and 14 patients with unicuspid (n = 3), bicuspid (n = 9, 3 “true” bicuspid, 3 right–left (RL), 3 right‐noncoronary (RN) leaflet fusion, and quadricuspid aortic valves (n = 2). Data analysis included the co‐registered visualization of aortic valve morphology with systolic 3D blood flow. The influence of valve morphology on aortic hemodynamics was quantified by valve flow angle.ResultsAll RL‐bicuspid aortic valve (BAV) were associated with flow jets directed toward the right anterior aortic wall while RN‐fusion and unicuspid valves resulted in flow jet patterns toward the right‐posterior or posterior wall. Flow angles were clearly influenced by valve morphology (47° ± 10, 28° ± 2, 29° ± 18, 18° ± 12, 15° ± 2 for unicuspid, true BAV, RN‐BAV, RL‐BAV, quadricuspid valves) and increased compared with controls (7.2° ± 1.1, P = 0.001).ConclusionAltered 3D aortic hemodynamics are impacted by the morphology of congenitally malformed aortic valves.J. Magn. Reson. Imaging 2014;40:1342–1346. © 2013 Wiley Periodicals, Inc.
Chromatic characterization of novel multicolor reflective display with electrochemically size‐controlled silver nanoparticles
Authors: Tsuboi Ayako , Nakamura Kazuki , Kobayashi Norihisa 
Published: November 2013

AbstractMultifunctional electrochromic materials that enable control of multiple colors, color density, and specular reflection are potential candidates for novel reflective display devices. In this research, we focus on Ag nanoparticles that exhibit various optical states based on their localized surface plasmon resonance (LSPR). Because the LSPR band depends on the size and shape of the nanoparticles, control of the morphology of Ag nanoparticles can lead to dramatic changes in color. In order to apply this color variation for display devices, we investigate here the electrochemical formation of size‐controlled Ag nanoparticles using a voltage‐step method that consists of an application of two successive different voltages (V1 and V2). The electrochemically deposited Ag nanoparticles appear red and blue depending on the time for V2 voltage application. The color changes between the transparent and colored states are reversible. Then, we successfully demonstrate the first LSPR‐based multicolor electrochromic device in which reversible control of five optical states—transparent, silver mirror, red, blue, and black—is possible.
Microstructural changes in sclera under thermo‐mechanical effect of 1.56 µm laser radiation increasing transscleral humor outflow
Authors: Baum Olga I. , Sobol Emil N. , Bolshunov Andrey V. , Fedorov Anatoly A. , Khomchik Olga V. , Omelchenko Alexander I. , Shcherbakov Evgenii M. 
Published: November 2013

AbstractBackground and ObjectivesPores in the sclera are a candidate pathway for aqueous transport and therefore can be utilized to decrease the intraocular pressure (IOP) in glaucomatous eyes. Since pore formation is a well‐known mechanism for stress relaxation in solids, laser‐induced creation of pores in cartilage increases hydraulic permeability and promotes tissue regeneration. The aim of this paper is to demonstrate the thermo‐mechanical effect of non‐destructive laser irradiation on microstructural changes in sclera, in particular pore formation, resulting in substantial increase of water permeability of eye tissues that can be a novel approach to normalize the IOP.Materials and MethodsExperiments were performed ex vivo on eight eyes of four mini‐pigs and in vivo on eight eyes of four rabbits using pulse repetitive laser radiation of 1.56 µm in wavelength. Twenty laser spots of 0.6 mm in diameter with laser settings (power 0.9 W, pulse duration of 200 milliseconds, pulse repetition rate of 2 Hz) resulting in substantial increase of sclera hydraulic permeability were applied on the sclera at 1–2 mm from the eye limb. Sclera and underlying structures (choroid and ciliary body) of the rabbits' eyes were examined histologically in 1 and 45 days after laser irradiation, atomic force microscope (AFM) was applied before and after laser irradiation.ResultsHistological and AFM examinations have clearly recognized laser‐assisted stable structural alterations: rarefication of the collagen structure in the laser irradiated zone and formation of sub‐micron pores. Laser‐induced alterations in the structure of ciliary bodies were small in size and mainly reversible. We have proposed a possible mechanism of the arising pores stabilization due to formation of small stable gas bubbles in sclera tissue.ConclusionsIt is shown, for the first time, that thermo‐mechanical effect of pulse repetitive laser irradiation results in pores formation in sclera. That can be a basis of a novel, safe, and effective technique for IOP normalization due to enhancing of uveoscleral outflow under non‐destructive laser irradiation of the sclera. Lasers Surg. Med. 46:46–53, 2014. © 2013 Wiley Periodicals, Inc.
Brain SPECT in Sydenham's chorea in remission
Authors: Beato Rogério , Siqueira Cristiano Ferrari , Marroni Belmonte J. , Boanova Luciane Guerra , de Lima Carla Flávia , Maia Débora Palma , Nattan Márcio , Cardoso Francisco 
Published: November 2013

ABSTRACTBackgroundSydenham's chorea, a major manifestation of rheumatic fever, is characterized by chorea, behavioral changes, and cognitive dysfunction. Perfusion changes in the basal ganglia are the most frequent imaging findings observed in patients with Sydenham's chorea.MethodsTwelve adult women with Sydenham's chorea in remission underwent brain single‐photon emission computed tomography (SPECT). Their scans underwent a quantification process to evaluate the perfusion of Brodmann's areas of the frontal lobes and basal ganglia. The results were compared with the findings from a control group that was matched by age.ResultsA pattern of hyperperfusion in the left putamen was observed in the patient group (P = 0.02). No significant difference was observed in relation to other brain regions.ConclusionsThe findings of brain SPECT suggest that perfusion abnormalities of the basal ganglia may persist even after the remission of abnormal movements in patients with Sydenham's chorea. © 2013 International Parkinson and Movement Disorder Society
Ultrahigh‐performance liquid chromatography/electrospray ionization linear ion trap Orbitrap mass spectrometry of antioxidants (amines and phenols) applied in lubricant engineering
Authors: Kassler Alexander , Pittenauer Ernst , Doerr Nicole , Allmaier Guenter 
Published: November 2013

RATIONALEFor the qualification and quantification of antioxidants (aromatic amines and sterically hindered phenols), most of them applied as lubricant additives, two ultrahigh‐performance liquid chromatography (UHPLC) electrospray ionization mass spectrometric methods applying the positive and negative ion mode have been developed for lubricant design and engineering thus allowing e.g. the study of the degradation of lubricants.METHODSBased on the different chemical properties of the two groups of antioxidants, two methods offering a fast separation (10 min) without prior derivatization were developed. In order to reach these requirements, UHPLC was coupled with an LTQ Orbitrap hybrid tandem mass spectrometer with positive and negative ion electrospray ionization for simultaneous detection of spectra from UHPLC‐high‐resolution (HR)‐MS (full scan mode) and UHPLC‐low‐resolution linear ion trap MS2 (LITMS2), which we term UHPLC/HRMS‐LITMS2.RESULTSAll 20 analytes investigated could be qualified by an UHPLC/HRMS‐LITMS2 approach consisting of simultaneous UHPLC/HRMS (elemental composition) and UHPLC/LITMS2 (diagnostic product ions) according to EC guidelines. Quantification was based on an UHPLC/LITMS2 approach due to increased sensitivity and selectivity compared to UHPLC/HRMS. Absolute quantification was only feasible for seven analytes with well‐specified purity of references whereas relative quantification was obtainable for another nine antioxidants. All of them showed good standard deviation and repeatability.CONCLUSIONSThe combined methods allow qualitative and quantitative determination of a wide variety of different antioxidants including aminic/phenolic compounds applied in lubricant engineering. These data show that the developed methods will be versatile tools for further research on identification and characterization of the thermo‐oxidative degradation products of antioxidants in lubricants. Copyright © 2013 John Wiley & Sons, Ltd.
Signal enhancement of carboxylic acids by inclusion with β‐cyclodextrin in negative high‐voltage‐assisted laser desorption ionization mass spectrometry
Authors: Ren Xinxin , Liu Jia , Zhang Chengsen , Sun Jiamu , Luo Hai 
Published: November 2013

RATIONALEIt is difficult to directly analyze carboxylic acids in complex mixtures by ambient high‐voltage‐assisted laser desorption ionization mass spectrometry (HALDI‐MS) in negative ion mode due to the low ionization efficiency of carboxylic acids.METHODSA method for the rapid detection of carboxylic acids in negative HALDI‐MS has been developed based on their inclusion with β‐cyclodextrin (β‐CD).RESULTSThe negative HALDI‐MS signal‐to‐noise ratios (S/Ns) of aliphatic, aromatic and hetero atom‐containing carboxylic acids can all be significantly improved by forming 1:1 complexes with β‐CD. These complexes are mainly formed by specific inclusion interactions which are verified by their collision‐induced dissociation behaviors in comparison with that of their corresponding maltoheptaose complexes. A HALDI‐MS/MS method has been successfully developed for the detection of α‐lipoic acid in complex cosmetics and ibuprofen in a viscous drug suspension.CONCLUSIONSThe negative HALDI‐MS S/Ns of carboxylic acids can be improved up to 30 times via forming non‐covalent complexes with β‐CD. The developed method shows the advantages of being rapid and simple, and is promising for rapid detection of active ingredients in complex samples or fast screening of drugs and cosmetics. Copyright © 2013 John Wiley & Sons, Ltd.
A generalized Pólya's urn with graph based interactions
Authors: Benaïm Michel , Benjamini Itai , Chen Jun , Lima Yuri 
Published: November 2013

AbstractGiven a finite connected graph G, place a bin at each vertex. Two bins are called a pair if they share an edge of G. At discrete times, a ball is added to each pair of bins. In a pair of bins, one of the bins gets the ball with probability proportional to its current number of balls raised by some fixed power . We characterize the limiting behavior of the proportion of balls in the bins.The proof uses a dynamical approach to relate the proportion of balls to a vector field. Our main result is that the limit set of the proportion of balls is contained in the equilibria set of the vector field. We also prove that if then there is a single point with non‐zero entries such that the proportion converges to v almost surely.A special case is when G is regular and . We show e.g. that if G is non‐bipartite then the proportion of balls in the bins converges to the uniform measure almost surely.Copyright © 2013 Wiley Periodicals, Inc. Random Struct. Alg., 46,614–634, 2015
Observation space for lowest PDOP in absolute‐range‐based 2‐D wireless location systems
Authors: Quan Qingyi 
Published: November 2013

AbstractA closed‐form expression for the position dilution of precision (PDOP) in absolute‐range‐based two‐dimensional (2‐D) wireless location systems is derived. Then, using the closed‐form expression, the observation space (OS) required for achieving the lowest PDOP of \documentclass{article}\usepackage{amsmath}\usepackage{amssymb}\usepackage{amsbsy}\usepackage{amsfonts}\pagestyle{empty}\begin{document}$2/\sqrt{N}$ \end{document} is studied, where N is the number of measuring points. The OS is measured by central angle of a sector which covers all measuring points. The target is located at the vertex of the sector. It is shown that, for achieving the lowest PDOP of \documentclass{article}\usepackage{amsmath}\usepackage{amssymb}\usepackage{amsbsy}\usepackage{amsfonts}\pagestyle{empty}\begin{document}$2/\sqrt{N}$\end{document}, the OS is required to be larger than or equal to π/2 while N is even. When N = 3, the OS is instead required to be larger than or equal to 2π/3. It is also shown that the OS of 2π/3 is sufficient to achieve the lowest PDOP of \documentclass{article}\usepackage{amsmath}\usepackage{amssymb}\usepackage{amsbsy}\usepackage{amsfonts}\pagestyle{empty}\begin{document}$2/\sqrt{N}$\end{document} while N is odd. © 2013 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.