bluuebunny/crossref_metadata_2025 huggingface dataset:
Stereochemistry of the Thermal Conversion of 1‐Vinyl‐2,3‐cis‐dideuteriocyclobutane to Butadiene and 1,2‐Dideuterioethylenes
Authors: Lewis David K. , Hutchinson Avery , Lever Steven J. , Spaulding Eric L. , Bonacorsi Samuel J. , Baldwin John E.
Published: November 2013

This study has examined the stereochemistry of the decomposition at 900–1000 K in a single‐pulse shock tube of 1‐vinyl‐2,3‐cis‐dideuteriocyclobutane to ethylenes and buta‐1,3‐dienes. The deuterated ethylenes formed during the decomposition, CHDCH2, (E)‐CHDCHD, and (Z)‐CHDCHD, were quantified via two independent techniques, FTIR and IR absorption spectroscopy using a tunable diode laser spectrometer. The results of both analyses indicated that equal amounts of (E)‐CHDCHD and (Z)‐CHDCHD were formed from the cis‐labeled reactant. In an earlier shock tube study of the decomposition at 1000–1200 K of two deuterium‐labeled cyclohexenes to ethylenes plus buta‐1,3‐dienes, a pathway via a vinylcyclobutane intermediate was implicated in a significant fraction of the decomposition events; the measured ratios of (E)‐CHDCHD to (Z)‐CHDCHD in that study were consistent with a complex mechanistic model in which the stereochemistry of deuterium labels in the cyclohexene reactant was lost in ethylene products formed via vinylcyclobutane. The present results provide additional support for that model.
Silicon Particle Formation in Pyrolysis of Silane and Disilane
Authors: Frenklach Michael , Ting Larry , Wang Hai , Rabinowitz Martin J.
Published: November 2013

Silane and disilane diluted in argon and hydrogen mixtures were pyrolyzed behind incident shock waves at temperatures ranging from 900 to 2000 K, pressures from 0.2 to 0.7 atm, and total concentration from 3 × 1016 to 1 × 1017 silicon atoms per cm3. Formation of silicon particles was monitored by the attenuation of laser beams of two different wavelengths, thereby determining particle size, number density, and fractional yield. The conversion of silane and disilane into silicon particles exhibited a pronounced maximum at about 1150 K, which was found to be affected by reaction pressure, initial reactant concentration, and addition of hydrogen. Selected silicon particle samples were examined by electron diffraction, transmission electron microscopy, and secondary ion mass spectrometry. The results indicated that the produced particles were spherical, ranging from 100 to 400 Å in diameter, loosely agglomerated, and contained about 15% hydrogen on an atomic basis. A detailed chemical kinetic model was developed that describes gas‐phase pyrolysis of the parent molecule and homogeneous nucleation of silicon particles by 117 elementary reactions of 42 chemical species, and coagulation of the forming particles and their growth by gas‐surface deposition reactions with a method of moments. The model predictions were found to be extremely sensitive to the values of optical constants assigned to the silicon particle material.
Reactions of Azides with Electrophiles: New Methods for the Generation of Cationic 2‐Azabutadienes. Synthesis of 1,2, 3,4‐Tetrahydroquinolines and 1,2‐Dihydroquinolines via a Hetero Diels–Alder Reaction
Authors: Pearson William H. , Fang Wen‐Kui
Published: November 2013

Two methods for the generation of iminium ions of the type ArN+(X)=CHR (X = H or alkyl, R = H or alkyl) are reported: (1) the Bronsted‐acid‐promoted rearrangement of benzylic azides and (2) the intermolecular Schmidt reactions of azides XN3 (X = aliphatic) with benzylic carbocations derived from benzylic alcohols ArCH(R)OH. The iminium ions ArN+(X)=CHR behave as cationic 2‐azabutadienes in the presence of alkenes and alkynes, producing 1,2, 3,4‐tetrahydroquinolines and 1,2‐dihydroquinolines by a hetero Diels–Alder reaction.
Desymmetrization of Prochiral Diesters Via Transition Metal Catalyzed Reactions
Authors: Trost Barry M.
Published: November 2013

The development of asymmetric induction in palladium catalyzed allylic alkylation has led to the notion of creating a chiral pocket. Two platforms for ligand design that may generate such “chiral space” evolve from derivatizing chiral diols or diamines with 2‐diphenylphosphinobenzoic acid or chiral diacids with 2‐diphenylphosphinoaniline. Palladium complexes derived from such ligands effect excellent enantiodiscrimination in the desymmetrization of esters of meso‐cycloalk‐2‐en‐1,4‐diols and gem dicarboxylates of α,β‐unsaturated aldehydes. These methods prove useful for asymmetric syntheses of carbanucleosides, nucleosides, and the antitumor alkaloid (+)‐pancratistatin.
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

The 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

Knowledge 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

In 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

Using 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

Voltage‐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

Terminal, 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.
Synthesis and Antibacterial Activity of New 2,5‐Diaryl‐3‐styryl‐4H,2,3,3a,5,6,6a‐hexahydropyrrolo[3,4‐d]isoxazole‐4,6‐diones
Authors: Kaur Anjandeep , Singh Baldev
Published: November 2013

The synthesis of some biologically interesting pyrrolo‐isoxazolidine derivatives has been accomplished by the 1,3‐dipolar cycloaddition reaction of substituted open chain conjugated azomethine N‐oxides 1 with substituted N‐aryl maleimides 2 leading to the formation of new stereoisomeric 2,5‐diaryl‐3‐styryl‐4H,2,3,3a,5,6,6a‐hexahydropyrrolo[3,4‐d]isoxazole‐4,6‐dione derivatives 3 in excellent yields. These stereoisomers have been characterized as cis‐3A and trans‐3B on the basis of their 1H‐NMR spectral measurements. The synthesized compounds have been screened for their antibacterial activities and have been found to be active against the bacteria Escherichia coli and Pseudomonas aeruginosa up to a significant extent.
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

Purpose

To 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 Methods

Aortic 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.

Results

All 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).

Conclusion

Altered 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

Multifunctional 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

Background and Objectives

Pores 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 Methods

Experiments 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.

Results

Histological 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.

Conclusions

It 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

Background

Sydenham'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.

Methods

Twelve 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.

Results

A 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.

Conclusions

The 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

RATIONALE

For 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.

METHODS

Based 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.

RESULTS

All 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.

CONCLUSIONS

The 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

RATIONALE

It 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.

METHODS

A method for the rapid detection of carboxylic acids in negative HALDI‐MS has been developed based on their inclusion with β‐cyclodextrin (β‐CD).

RESULTS

The 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.

CONCLUSIONS

The 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

Given 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

A 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.
Amnioinfusion in very early preterm prelabor rupture of membranes (AMIPROM): pregnancy, neonatal and maternal outcomes in a randomized controlled pilot study
Authors: Roberts D. , Vause S. , Martin W. , Green P. , Walkinshaw S. , Bricker L. , Beardsmore C. , Shaw N. , McKay A. , Skotny G. , Williamson P. , Alfirevic Z.
Published: November 2013

Objective

To assess short‐ and long‐term outcomes of pregnant women with very early rupture of membranes randomized to serial amnioinfusion or expectant management, and to collect data to inform a larger, more definitive clinical trial.

Methods

This was a prospective non‐blinded randomized controlled trial with randomization stratified for pregnancies in which the membranes ruptured between 16 + 0 and 19 + 6 weeks' gestation and 20 + 0 and 23 + 6 weeks' gestation to minimize the risk of random imbalance in gestational age distribution between randomized groups. Intention‐to‐treat analysis was used. The study was conducted in four UK hospital‐based fetal medicine units (Liverpool Women's NHS Trust, St Mary's Hospital Manchester, Birmingham Women's NHS Foundation Trust and Wirral University Hospitals Trust). The participants were women with confirmed preterm prelabor rupture of membranes at 16 + 0 to 24 + 0 weeks' gestation. Women with multiple pregnancy, fetal abnormality or obstetric indication for immediate delivery were excluded. Participants were randomly allocated to either serial weekly transabdominal amnioinfusions if the deepest pool of amniotic fluid was < 2 cm or expectant management until 37 weeks' gestation. Short‐term maternal, pregnancy and neonatal and long‐term outcomes for the child were studied. Long‐term respiratory morbidity was assessed using validated respiratory questionnaires at 6, 12 and 18 months of age and infant lung function test at around 12 months of age. Neurodevelopment was assessed using the Bayley Scales of Infant Development, second edition (BSID‐II) at corrected age of 2 years.

Results

Fifty‐eight women were randomized to the study. Two babies were excluded from the analysis because of termination of pregnancy for lethal anomaly, leaving 56 participants (28 assigned to serial amnioinfusion and 28 to expectant management) recruited between 2002 and 2009. There was no significant difference in perinatal mortality (19/28 vs 19/28; relative risk (RR) 1.0 (95% CI, 0.70–1.43)) and maternal or neonatal morbidity. The overall chance of surviving without long‐term respiratory or neurodevelopmental disability was 4/56 (7.1%); 4/28 (14.3%) in the amnioinfusion group and 0/28 in the expectant group (RR 9.0 (95% CI, 0.51–159.70)).

Conclusions

This pilot study found no major differences in maternal, perinatal or pregnancy outcomes. The study was not designed to show a difference between the groups and the number of survivors was too small to draw any conclusions about long‐term outcomes. It does, however, signal that a larger definitive study to evaluate amnioinfusion for improvement in healthy survival is needed. The pilot suggests that, with appropriate funding, such a study is feasible. Copyright © 2013 ISUOG. Published by John Wiley & Sons Ltd.
Seeking Balance: Decision Support Needs of Women Without Cancer and a Deleterious BRCA1 or BRCA2 Mutation
Authors: Underhill Meghan L. , Crotser Cheryl B.
Published: November 2013

Recommendations for women with a deleterious BRCA1 or BRCA2 gene mutation include complex medical approaches related to cancer risk reduction and detection. Current science has not yet fully elucidated decision support needs that women face when living with medical consequences associated with known hereditary cancer risk. The purpose of this study was to describe health communication and decision support needs in healthy women with BRCA1/2 gene mutations. The original researchers completed an interpretive secondary qualitative data analysis of 23 phenomenological narratives collected between 2008 and 2010. The Ottawa Decision Support and Patient Centered Communication frameworks guided the study design and analysis. Women described a pattern wherein breast and ovarian cancer risk, health related recommendations and decisions, and personal values were prioritized over time based on life contexts. Knowing versus acting on cancer risk was not a static process but an ongoing balancing act of considering current and future personal and medical values, further compounded by the complexity of recommendations. Women shared stories of anticipatory, physical and psychosocial consequences of the decision making experience. The findings have potential to generate future research questions and guide intervention development. Importantly, findings indicate a need for ongoing, long‐term, support from genetics professionals and decision support interventions, which challenges the current practice paradigm.
A Class of Distribution-Free Models for Longitudinal Mediation Analysis
Authors: Gunzler D. , Tang W. , Lu N. , Wu P. , Tu X. M.
Published: November 2013

Mediation analysis constitutes an important part of treatment study to identify the mechanisms by which an intervention achieves its effect. Structural equation model (SEM) is a popular framework for modeling such causal relationship. However, current methods impose various restrictions on the study designs and data distributions, limiting the utility of the information they provide in real study applications. In particular, in longitudinal studies missing data is commonly addressed under the assumption of missing at random (MAR), where current methods are unable to handle such missing data if parametric assumptions are violated.

In this paper, we propose a new, robust approach to address the limitations of current SEM within the context of longitudinal mediation analysis by utilizing a class of functional response models (FRM). Being distribution-free, the FRM-based approach does not impose any parametric assumption on data distributions. In addition, by extending the inverse probability weighted (IPW) estimates to the current context, the FRM-based SEM provides valid inference for longitudinal mediation analysis under the two most popular missing data mechanisms; missing completely at random (MCAR) and missing at random (MAR). We illustrate the approach with both real and simulated data.
Synthesis and Evaluation of Some Triazole Derivatives as Corrosion Inhibitors and Biocides
Authors: Abd‐Elaal Ali A. , Aiad Ismail , Shaban Samy M. , Tawfik Salah M. , Sayed Atef
Published: November 2013

Three compounds namely; 5‐(phenyl)‐4H‐1,2,4‐triazole‐3‐thiol, 3‐(decylthio)‐5‐phenyl‐1H‐1,2,4‐triazole and 3‐(benzylthio)‐5‐phenyl‐1H‐1,2,4‐triazole) were synthesized. The chemical structure of the prepared compounds was confirmed using FTIR and 1H‐NMR analysis. The compounds were tested as corrosion inhibitors against the corrosion of carbon steel in 1 M HCl using weight loss, polarization and electrochemical impedance methods. The results revealed that these compounds have significant inhibiting effects on the corrosion of carbon steel. Polarization studies showed that the compounds act as mixed‐type inhibitors which retard the anodic and the cathodic reactions with a predominant effect towards the cathodic reaction. The prepared compounds were evaluated as antimicrobial agents against sulfate‐reducing bacteria using the serial dilution method, which showed good biocidal action.
The externalizing spectrum in youth: Incorporating personality pathology
Authors: Tackett Jennifer L. , Herzhoff Kathrin , Reardon Kathleen W. , De Clercq Barbara , Sharp Carla
Published: November 2013

Although personality disorder characteristics are often grouped with externalizing problems in adults, little is known about the extent to which they define the externalizing spectrum in youth. We examined the extent to which personality pathology traits in youth reflected common and specific variance in externalizing problems and explored differentiation of these connections by age. Parents reported on physical aggression, rule‐breaking, relational aggression, and personality pathology traits for 1080 youth (48.8% male) ages 6–18 years. Disagreeableness and emotional instability traits were correlated with a general externalizing factor as well as with specific behavioral subfactors. The magnitude of these correlations varied across age, with the highest magnitude evidenced during the developmental periods of greatest prevalence for the specific externalizing behavior subtype. Taken together, these findings suggest that personality pathology is tightly connected with externalizing problems in youth, especially during developmental periods when externalizing problems are common.
Brief report: Self‐blame and PTSD symptoms in adolescents exposed to terrorism: Is school connectedness a mediator?
Authors: Moscardino Ughetta , Scrimin Sara , Capello Fabia , Altoè Gianmarco
Published: November 2013

Previous research has shown that self‐blame predicts increased risk of posttraumatic stress disorder (PTSD) in youth exposed to terrorism, but little is known about the factors mediating such relationship. This study aimed to explore whether school connectedness (SC) mediates the effect of self‐blame on PTSD in 60 adolescents (aged 14–18 years) who survived the 2004 terrorist attack against school no. 1 in Beslan, Russia. Participants completed measures of coping, SC, and PTSD three years after the traumatic event. Endorsement of self‐blaming behaviors was found to be significantly positively related to the presence of PTSD; self‐blame was negatively associated with SC, which in turn was negatively related to PTSD. The mediation hypothesis was supported, with SC partially mediating the link between self‐blame and PTSD. Adolescents affected by terrorism may benefit from school‐based interventions aimed at fostering students' sense of belonging and emotional bonding to teachers, peers, and the school environment.
The Socialist Regime: The Intellectual Origin of the Images
Authors: Shlapentokh Dmitry
Published: November 2013

Every phenomenon exists in several dimensions. It has several ontological attributes, so to speak, which provide opportunities for a variety of interpretations. The Bolshevik Revolution and the Soviet regime could be an example. At the beginning of Soviet history the revolution was seen as the beginning of a worldwide revolution opening an era of liberation for workers all over the world. As the Soviet regime solidified its position, the hope for worldwide revolution faded. In the new context, observers, especially outside Russia, looked at the regime from a different perspective. For them it represented the country's national interests, and its socialist slogans should not be taken at face value. Some believed post-revolutionary Russia was similar to post-revolutionary France and was experiencing its “Thermidor.” Others assumed the revolution showed Russia as a “Eurasian” state where all ethnic/religious groups lived in “symbiosis.” Finally, some assumed the Soviet regime would lead to the transformation of the human species and the human conquest of cosmos. This transition from one image to another does not mean that one illusion, one “wrong” image, follows another. It also does not mean the very notion of true meaning is meaningless simply because no reality exists as a fixed entity, and one could therefore “construct” any type of reality. It simply means that there are many attributes of the revolution, which are revealed in the course of time.
Macrophage mitochondrial damage from StAR transport of 7‐hydroperoxycholesterol: Implications for oxidative stress‐impaired reverse cholesterol transport
Authors: Korytowski Witold , Wawak Katarzyna , Pabisz Pawel , Schmitt Jared C. , Girotti Albert W.
Published: November 2013

StAR family proteins in vascular macrophages participate in reverse cholesterol transport (RCT). We hypothesize that under pathophysiological oxidative stress, StARs will transport not only cholesterol to macrophage mitochondria, but also pro‐oxidant cholesterol hydroperoxides (7‐OOHs), thereby impairing early‐stage RCT. Upon stimulation with dibutyryl‐cAMP, RAW264.7 macrophages exhibited a strong time‐dependent induction of mitochondrial StarD1 and plasma membrane ABCA1, which exports cholesterol. 7α‐OOH uptake by stimulated RAW cell mitochondria (like cholesterol uptake) was strongly reduced by StarD1 knockdown, consistent with StarD1 involvement. Upon uptake by mitochondria, 7α‐OOH (but not redox‐inactive 7α‐OH) triggered lipid peroxidation and membrane depolarization while reducing ABCA1 upregulation. These findings provide strong initial support for our hypothesis.
Effects of ribosomes on the kinetics of Qβ replication
Authors: Usui Kimihito , Ichihashi Norikazu , Kazuta Yasuaki , Matsuura Tomoaki , Yomo Tetsuya
Published: November 2013

Bacteriophage Qβ utilizes some host cell translation factors during replication. Previously, we constructed a kinetic model that explains replication of long RNA molecules by Qβ replicase. Here, we expanded the previous kinetic model to include the effects of ribosome concentration on RNA replication. The expanded model quantitatively explained single‐ and double‐strand formation kinetics during replication with various ribosome concentrations for two artificial long RNAs. This expanded model and the knowledge obtained in this study provide useful frameworks to understand the precise replication mechanism of Qβ replicase with ribosomes and to design amplifiable RNA genomes in translation‐coupling systems.
Skeletal muscle glycogen phosphorylase is irreversibly inhibited by mercury: Molecular, cellular and kinetic aspects
Authors: Xu Ximing , Mathieu Cécile , Boitard Solène Emmanuelle , Dairou Julien , Dupret Jean-Marie , Agbulut Onnik , Rodrigues-Lima Fernando
Published: November 2013

Muscle glycogen phosphorylase (GP) plays an important role in muscle functions. Mercury has toxic effects in skeletal muscle leading to muscle weakness or cramps. However, the mechanisms underlying these toxic effects are poorly understood. We report that GP is irreversibly inhibited by inorganic (Hg2+) and organic (CH3Hg+) mercury (IC50
= 380 nM and k
inact
= 600 M−1
s−1 for Hg2+ and IC50
= 43 μM and k
inact
= 13 M−1
s−1 for CH3Hg+) through reaction of these compounds with cysteine residues of the enzyme. Our data suggest that the irreversible inhibition of GP could represent one of the mechanisms that contribute to mercury‐dependent muscle toxicity.
The ALS/FTLD‐related RNA‐binding proteins TDP‐43 and FUS have common downstream RNA targets in cortical neurons
Authors: Honda Daiyu , Ishigaki Shinsuke , Iguchi Yohei , Fujioka Yusuke , Udagawa Tsuyoshi , Masuda Akio , Ohno Kinji , Katsuno Masahisa , Sobue Gen
Published: November 2013

TDP‐43 and FUS are linked to amyotrophic lateral sclerosis (ALS) and frontotemporal lobar degeneration (FTLD), and loss of function of either protein contributes to these neurodegenerative conditions. To elucidate the TDP‐43‐ and FUS‐regulated pathophysiological RNA metabolism cascades, we assessed the differential gene expression and alternative splicing profiles related to regulation by either TDP‐43 or FUS in primary cortical neurons. These profiles overlapped by >25% with respect to gene expression and >9% with respect to alternative splicing. The shared downstream RNA targets of TDP‐43 and FUS may form a common pathway in the neurodegenerative processes of ALS/FTLD.
West Pacific-type convergent boundaries and their role in the formation of the Central Asian Fold Belt
Authors: Yarmolyuk V.V. , Kuz’min M.I. , Vorontsov A.A.
Published: November 2013

The type of convergent boundaries forming in the area of mantle plumes is considered. These convergent boundaries (West Pacific type) are characteristic of the western margin of the Pacific. West Pacific-type boundaries are a regular succession of structures from ocean to continent: island arcs, marginal basins, rift basins, and associated OIB-type volcanics at the continental edge. The convergence zones are up to a thousand kilometers wide.

Studies of the history of the part of the Central Asian Fold Belt forming the folded periphery of the Siberian continent have shown that the continent drifted above the African plume or corresponding low-velocity mantle province for most of the Phanerozoic (up to the Early Mesozoic inclusive). This fact determined the West Pacific type of convergent boundaries for the accretionary structures of the Central Asian Fold Belt. The drift of Siberia from African to Pacific province in the Late Cenozoic determined the structure and development of the convergent boundary in the western Pacific, including extensive intraplate magmatism in continental Asia in the Late Mesozoic and Cenozoic.
Thermal conductivity of sediments in high-latitude West Siberia
Authors: Duchkov A.D. , Sokolova L.S. , Ayunov D.E. , Zlobina O.N.
Published: November 2013

The thermal conductivity of rocks (λ) used previously to estimate heat flow in high-latitude Siberia was assumed to be λ = 1.8–2.0 W/(m⋅K), according to published evidence, but was almost never measured specially. We measured the thermal conductivity of core samples from boreholes drilled in the northeastern West Siberian Plate and in the Yenisei–Khatanga basin in the 1990s, using two advanced instruments: a comparator and a scanner of thermal conductivity. Altogether there were 305 samples of air-dry sediments (λd) from the 1100–4200 m interval of 23 holes, out of which 77 samples were then moistened (λw). The average thermal conductivities of rocks in dry and wet conditions were found to be λd = 1.9 ± 0.2 and λw = 2.6 ± 0.1 W/(m⋅K), respectively. Thus, the true thermal conductivity of sediments, which are saturated with water in this northern area, must be about 20–30% higher than that assumed in the previous heat flow determinations, and the latter are thus underestimated correspondingly. The updates to the thermal conductivity values imply major revision to the existing ideas of the thermal regime in the Siberian high latitudes. Such a serious revision of geothermal data will obviously require a large amount of additional experimental work.
The function of Student Pidgin in Ghana
Authors: Rupp Laura
Published: November 2013

The emergence of Student Pidgin in Ghana is estimated to have started fairly recently: between 1965 and the early 1970s (Huber, 1999; Dako, 2002). Male students in high prestige senior secondary schools and universities have been credited with leading in the development of Student Pidgin. The use of Student Pidgin has since been spreading among some girls and is currently found in an increasing number of contexts, including the home. The fact that students use Student Pidgin seems unexpected, considering the fact that they are competent speakers of Standard English.2 In this context, the question to consider is what underlies this behavior? This has been the subject of recurrent debate. Educational authorities typically feel that Student Pidgin reflects the fact that the standard of English in Ghanaian senior secondary schools and universities has fallen. An example of this comes from a speech given by the Vice Chancellor of the University of Ghana, Professor Kwadwo Asenso-Okyere, on 28 October 2002:

[He] expressed concern about the standard of English among university students and advised them to desist from speaking Pidgin English, which he said would not help them. Speaking at this year's matriculation of 7,959 freshmen out of the 10,301 admitted into the University, Prof Asenso-Okyere said there was evidence of deterioration in English Language among students in their examinations and theses, which some employers had also complained about.