bluuebunny/crossref_metadata_2025_split huggingface dataset:
Synthesis, structural characterization, and olefin polymerization behavior of vanadium(III) complexes bearing bidentate phenoxy‐phosphine ligands
Authors: Zhang Sen‐Wang , Lu Ling‐Pan , Li Bai‐Xiang , Li Yue‐Sheng 
Published: August 2012

AbstractVanadium(III) complexes bearing phenoxy‐phosphine ligands (2a–g) (2‐R1‐4‐R2‐6‐PPh2‐C6H2O)VCl2(THF)2 (2a: R1 = R2 = H; 2b: R1 = F, R2 = H; 2c: R1 = Ph, R2 = H; 2d: R1 = tBu, R2 = H; 2e: R1 = R2 = Me; 2f: R1 = R2 = tBu; 2g: R1 = R2 = CMe2Ph) were prepared from VCl3(THF)3 by treating with 1.0 equiv of the ligand in tetrahydrofuran (THF) in the presence of excess triethylamine (TEA). The reaction of VCl3(THF)3 with 2.0 equiv of the ligand in THF in the presence of excess TEA afforded vanadium(III) complexes bearing two phenoxy‐phosphine ligands (3c–f). These complexes were characterized by FTIR and mass spectrum as well as elemental analyses. Structures of 2f and 3c were further confirmed by X‐ray crystallographic analyses. Complexes 2a–g and 3c–f were employed as the catalysts for ethylene polymerization under various reaction conditions. On activation with Et2AlCl, these complexes exhibited high catalytic activities (up to 41.3 kg PE/mmolV·h·bar) even at high temperature (70°C), and produced high molecular weight polymer with unimodal molecular weight distributions, indicating the polymerization took place in a single‐site nature. Complexes 3c–f displayed better thermal stability than the corresponding complexes 2a–g under similar conditions. In addition, copolymerizations of ethylene and 1‐hexene with precatalysts 2a–g were also explored in the presence of Et2AlCl. Catalytic activity, comonomer incorporation, and properties of the resultant polymers can be controlled over a wide range by tuning catalyst structures and reaction parameters.© 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012
Single‐pulse pulsed laser polymerization–electron paramagnetic resonance investigations into the termination kinetics of n‐butyl acrylate macromonomers
Authors: Barth Johannes , Buback Michael , Barner‐Kowollik Christopher , Junkers Tanja , Russell Gregory T. 
Published: August 2012

AbstractThe termination of model mid‐chain radicals (MCRs), which mimic radicals that occur in acrylate polymerization over a broad range of reaction conditions, has been studied by single‐pulse pulsed laser polymerization (SP‐PLP) in conjunction with electron paramagnetic resonance spectroscopy. The model radicals were generated by initiator‐fragment addition to acrylic macromonomers that were preformed prior to the kinetic experiments, thus enabling separation of termination from the propagation reaction, for these model radicals propagate sparingly, if at all, on the timescale of SP‐PLP experiments. Termination rate coefficients of the MCRs were determined in the temperature range of 0–60°C in acetonitrile and butyl propionate solution as well as in bulk macromonomer over the range of 0–100 °C. Termination rate coefficients slightly below those of the corresponding secondary radicals were deduced, demonstrating the relatively high termination activity of this species, even when undergoing MCR–MCR termination. For chain length of 10, a reduction by a factor of 6 is observed. Unusually high activation energies were found for the termination rate coefficient in these systems, with 35 kJ mol−1 being determined for bulk macromonomer. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012
Isomeric effect of sulfonated poly(arylene ether)s comprising dihydroxynaphthalene on properties for polymer electrolyte membranes
Authors: Sakaguchi Yoshimitsu , Kitamura Kota , Takase Satoshi 
Published: August 2012

AbstractPolymer electrolyte membranes (PEMs) made of sulfonated poly(arylene ether)s consisted of 3,3′‐disulfo‐4,4′‐dichlorodiphenylsulfone disodium salt, 2,6‐dichlorobenzonitrile, and one of three dihydroxynaphthalene isomers (2,6‐, 2,7‐, and 1,5‐dihydroxynaphthalene, abbreviated as 2,6‐N, 2,7‐N, and 1,5‐N, respectively) were prepared with similar level of inherent viscosity and ion exchange capacity, and structural effect of the catenation in dihydroxynaphthalene isomers on membrane properties was compared. In the case of membranes for PEM fuel cell application with relatively high ion exchange capacity around 2.1 mequiv/g, three copolymers showed almost the same proton conductivity; however, swelling in water increased with the following order: 1,5‐N < 2,6‐N < 2,7N. In the case of direct methanol fuel cell membranes with lower ion exchange capacity around 1.5 mequiv/g, no remarkable difference in proton conductivity was also observed in three isomeric copolymers and swelling property and methanol permeability were lower in 1,5‐N and 2,6‐N copolymers than 2,7‐N copolymer. These tendencies show that higher rigidity or energy barrier for conformational change of polymer chain gives better performance of PEM for fuel cells with superior dimensional stability. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012
Synthesis of networked polymer based on ring‐opening addition reaction of 1,3‐benzoxazine with resorcinol
Authors: Oie Hiroaki , Mori Atsushi , Sudo Atsushi , Endo Takeshi 
Published: August 2012

AbstractA highly efficient ring‐opening addition reaction of benzoxazine at ambient temperature has been developed with 2‐methylresorcinol as a nucleophilic reagent. In this reaction, 2‐methylresorcinol reacted with two equivalent amount of benzoxazine to give the corresponding 1:2 adduct, demonstrating its potential as a bifunctional nucleophile. Based on this reaction, a new crosslinking system consisting of a polymer bearing benzoxazine moieties in the side chains and 2‐methylresorcinol as a crosslinker has been performed to obtain the corresponding networked polymer. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012
Synthesis of stable aqueous dispersion of graphene/polyaniline composite mediated by polystyrene sulfonic acid
Authors: Luo Jing , Jiang Sisi , Wu Yong , Chen Meiling , Liu Xiaoya 
Published: August 2012

AbstractA facile method of producing stable aqueous dispersion of graphene/polyaniline (PANI) composite is described, which involves the in situ polymerization of aniline on the surface of graphene with the aid of polystyrene sulfonic acid (PSS). The prepared aqueous graphene/PANI composite dispersion was very stable and no aggregation or precipitation was observed for several weeks. The excellent aqueous dispersibility and stability of the graphene/PANI composite is attributed to the cooperative interactions of π stacking interaction between PSS, PANI, and the graphene basal planes, and the electrostatic repulsions between negatively charged PSS bound on graphene/PANI composite. Fourier transform‐infrared spectrometry (FTIR), ultraviolet‐visible spectra (UV–vis), and Raman spectra confirmed the interaction of PANI and graphene in the composite, which effectively delocalize the electrons. In addition, the composite showed three orders of magnitude of conductivity increase compared with pure PANI. This new approach is simple, fast, and straightforward, representing a significant improvement in the processing of graphene/PANI composites. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012
Relation between photodarkening and photoexpansion in As2S3 glass
Authors: Tanaka Keiji 
Published: August 2012

AbstractWe study comparatively some characteristics of photodarkening and photoexpansion in chalcogenide glasses. In thicker samples, both grow more slowly, but the thickness variations are different. The feature can be understood with an idea that the two phenomena originate from a common atomic displacement, while the expansion in thick films suffers marked delays, due to viscous transfer of photogenerated internal stress to sample surfaces. Densities of the common atomic site are estimated at 0.5–1 at.%, the situation corresponding to single isolated (uncorrelated) centres in medium‐range structures, which provides the quasi‐stability of illuminated states. We also discuss relations between the darkening, the expansion (density reduction), and a refractive‐index increase.
Memories of a visiting scientist
Authors: Mytilineou Eugenia 
Published: August 2012

AbstractStan Ovshinsky, the man who practically started the field of amorphous semiconductors in the West, is 90 years old this year. He always keeps the enthusiasm of a teenager and the slim and tall figure of a cypress tree. Stan's personality actually reminds me of these characteristic trees of the Mediterranean landscape; with their narrow tall figures pointing towards the sky and popping out of any green background surrounding them. Stan feels and behaves as a young man; even at the age of 85, following his old dream for changing the world, he founded a new company. I first met Stan and Iris in 1977. Since then, I have spent several sabbatical leaves in Energy Conversion Devices (ECD), from 1984 to 2004. In the following, our scientific collaboration and the build up of a very deep and sincere friendship will be described.
Emerging topological insulating phase in GeSbTe compounds
Authors: Kim Jeongwoo , Jhi Seung‐Hoon 
Published: August 2012

AbstractThe electronic property of GeSbTe compounds is studied within the notion of their topological insulating phase. We show that these compounds, as pseudo‐binary alloys of GeTe and Sb2Te3, in their crystalline phase with well‐ordered layer stacking have imbedded surface‐like states originating from topological insulating Sb2Te3 at interfaces between GeTe and Sb2Te3 layers. We demonstrate that these conducting states can significantly affect the electrical conduction of the compounds and are sensitive to Ge migration. Using first‐principles methods, we show that the topological insulating phase of GeSbTe compounds can be manipulated by controlling the composition and/or layer thickness. It is found that the interaction between the surface‐like states intervened by insulating GeTe layers creates an inversion gap to turn the compounds into topological insulating phase. We anticipate that the topological insulating property of GeSbTe can provide new insight into understanding the underlying physics in structural transitions of the compounds and a perspective of utilizing phase change materials as spin‐control devices as well as non‐volatile memory devices.
Phase‐change processors, memristors and memflectors
Authors: Wright C. David , Wang Lei , Aziz Mustafa M. , Diosdado Jorge A. Vazquez , Ashwin Peter 
Published: August 2012

AbstractPhase‐change materials exhibit some remarkable properties. They can be crystallized in picoseconds and amorphized in femtoseconds, but remain stable against spontaneous crystallization for many years. They exhibit huge differences in optical and electrical properties between the amorphous and crystalline phases. Such properties have led, over the last four decades, to the successful development of both optical and electrical non‐volatile phase‐change memories. However, such binary memories only ‘scratch the surface’ in terms the remarkable potential applications of phase‐change materials and devices, which extend to arithmetic, logical and bio‐inspired (or neuromorphic) processing. In this paper we introduce and explain some of this remarkable functionality inherent to phase‐change systems. Phase‐change device operating in accumulation mode. This provides the basic mechanism for providing arithmetic, logic and neuronal type processing.magnified image
Short range order and Ag diffusion threshold in Agx(Ge0.25Se0.75)100−x glasses
Authors: Piarristeguy A. A. , Cuello G. J. , Fernández‐Martínez A. , Cristiglio V. , Johnson M. , Ribes M. , Pradel A. 
Published: August 2012

AbstractA structural investigation of Agx(Ge0.25Se0.75)100 − x glasses with x = 5, 15, and 25 at.% has been carried out by neutron diffraction and ab initio molecular dynamics (AIMD) simulation. A structural model for the glasses has been proposed: the Ge(Se1/2)4 tetrahedra would remain the fundamental structural units in all samples. The introduction of Ag in the Ge0.25Se0.75 network would lead to a decrease in homopolar SeSe bonds and appearance of GeGe bonds. A strong evolution in the AgAg correlations upon introduction of Ag was observed with the AgAg correlation distances changing from 4.4 Å for the Ag‐poor glass to 3.0 Å for the Ag‐rich ones. Such information was used to discuss the evolution of conductivity with Ag content in these glasses.
Alloy solid solution strengthening of Mg alloys: Valence effect
Authors: Chen Kuiying , Boyle Kevin P. 
Published: August 2012

AbstractAb initio density functional theory (DFT) calculations were carried out to investigate alloy solid solution strengthening of hexagonal close packed (HCP) Mg. The binary solid solution Mg–X base alloys (X = Gd, Nd, Ce, Bi, In, and Sn) were examined to identify a possible valence effect on the solution strengthening in terms of electronic density of states (DOS) and electron localized function (ELF). An addition of rare earth (RE) elements Gd, Nd, and Ce in Mg results in a hybridization between the localized f electrons of RE elements and the p electrons of Mg. The hybridization is primarily responsible for the formation of covalent bonds between RE elements and Mg. This electronic structure was then validated by the calculated ELF, illustrating a distribution of localized electrons between Mg and RE atoms. This peculiar chemical bonding characteristic successfully explains the experimentally observed solid solution strengthening induced by Gd, Nd, and Ce additions. An addition of sp‐elements of Bi, In, and Sn in Mg, however, leads to the formation of typical ionic bonds, which are not capable of inducing solid solution strengthening in Mg alloys. A discussion was made on a possible relationship between the chemical bonds and solid solution strengthening in Mg alloys.
Testing for white noise against locally stationary alternatives
Authors: Goerg Georg M. 
Published: August 2012

AbstractMany real‐world systems have dynamics that evolve over time, yet stationary models still remain a popular choice in empirical time series studies. In this work, I show that one reason for seemingly correct stationary fits is a very low power of classic white noise tests against locally varying dynamics. In particular, if autocorrelations change over time but on average equal zero, standard white noise tests cannot detect this deviation from the null hypothesis due to their fundamental design. Here I introduce a moving‐window version of the Ljung–Box statistic with an asymptotic\documentclass{article}\usepackage{amsmath}\usepackage{amssymb}\usepackage{amsbsy}\usepackage{amsfonts}\pagestyle{empty}\begin{document}$\chi^{2}$ \end{document}distribution under the null and much larger power facing processes with time‐varying autocorrelations. Simulations and a case study of tree‐ring data demonstrate the importance of the new test for applied time series studies. © 2012 Wiley Periodicals, Inc. Statistical Analysis and Data Mining, 2012
Decoupling market incumbency from organizational prehistory: Locating the real sources of competitive advantage in R&D for radical innovation
Authors: Lourdes Sosa M. 
Published: August 2012

AbstractThe creative destruction literature has argued that differences in R&D performance of incumbent vs. entrant firms can be explained through organizational change theories about established vs. de novo firms. A disconnect exists between these theories and the available empirical evidence because often the best performing firms are established firms as well. I propose to resolve this disconnect by distinguishing between market incumbency (presence in a market prior to a discontinuity) and organizational prehistory (organizational experience prior to a transition, whether between technologies or between markets). Doing so allows me to contrast incumbent vs. entrant and de alio vs. de novo studies, and to suggest more robust future research designs. I illustrate my proposition using qualitative data from the anticancer and AIDS‐treatment drug markets. Copyright © 2012 John Wiley & Sons, Ltd.
Reverse engineering of gene regulatory networks from biological data
Authors: Liu Li‐Zhi , Wu Fang‐Xiang , Zhang Wen‐Jun 
Published: August 2012

AbstractReverse engineering of gene regulatory networks (GRNs) is one of the most challenging tasks in systems biology and bioinformatics. It aims at revealing network topologies and regulation relationships between components from biological data. Owing to the development of biotechnologies, various types of biological data are collected from experiments. With the availability of these data, many methods have been developed to infer GRNs. This paper firstly provides an introduction to the basic biological background and the general idea of GRN inferences. Then, different methods are surveyed from two aspects: models that those methods are based on and inference algorithms that those methods use. The advantages and disadvantages of these models and algorithms are discussed. © 2012 Wiley Periodicals, Inc.This article is categorized under:Algorithmic Development > Biological Data Mining
Flocculation of microfibrillated cellulose in shear flow
Authors: Karppinen Anni , Saarinen Tapio , Salmela Juha , Laukkanen Antti , Nuopponen Markus , Seppälä Jukka 
Published: August 2012

AbstractIn this work, the rheological properties of microfibrillated cellulose suspensions under stepped flow and constant shear were studied using a combination of rotational dynamic rheometer and digital imaging. During each rheological measurement, the structure of the suspension was monitored through a transparent outer cylinder with a digital camera. This enabled simultaneous analysis of the suspension floc size distribution and traditional rheological characterization. In stepped flow conditions, a good correlation between suspension floc structure and flow curve measurement was found. At constant shear, the suspension structure was dependent on the shear rate and concentration of the suspension. A low shear rate resulted in heterogeneous floc structure, which was also detected by an increase in the ratio of the viscous component to elastic component in the rheological measurement. At low concentrations and 0.5 s−1shear rate, flow induced a formation of floc cylinders between the rotating cylinder and stationary cup surface.
“Grasping the Grey”: Patient Understanding and Interpretation of an Intermediate Allele Predictive Test Result for Huntington Disease
Authors: Semaka A. , Balneaves L. G. , Hayden M. R. 
Published: August 2012

AbstractSince the discovery of the genetic mutation underlying Huntington disease (HD) and the development of predictive testing, the genetics of HD has generally been described as straightforward; an individual receives either mutation‐positive or negative predictive test results. However, in actuality, the genetics of HD is complex and a small proportion of individuals receive an unusual predictive test result called an intermediate allele (IA). Unlike mutation‐positive or negative results, IAs confer uncertain clinical implications. While individuals with an IA will usually not develop HD, there remains an unknown risk for their children and future generations to develop the disorder. The purpose of this study was to explore how individuals understood and interpreted their IA result. Interviews were conducted with 29 individuals who received an IA result and 8 medical genetics service providers. Interviews were analyzed using the constant comparative method and the coding procedures of grounded theory. Many participants had difficulty “Grasping the Grey” (i.e. understanding and interpreting their IA results) and their family experience, beliefs, expectations, and genetic counseling influenced the degree of this struggle. The theoretical model developed informs clinical practice regarding IAs, ensuring that this unique subset of patients received appropriate education, support, and counseling.
Predicted Changes in Fatty Acid Intakes, Plasma Lipids, and Cardiovascular Disease Risk Following Replacement of trans Fatty Acid‐Containing Soybean Oil with Application‐Appropriate Alternatives
Authors: Lefevre Michael , Mensink Ronald P. , Kris‐Etherton Penny M. , Petersen Barbara , Smith Kim , Flickinger Brent D. 
Published: August 2012

AbstractThe varied functional requirements satisfied by trans fatty acid (TFA)—containing oils constrains the selection of alternative fats and oils for use as potential replacements in specific food applications. We aimed to model the effects of replacing TFA‐containing partially hydrogenated soybean oil (PHSBO) with application‐appropriate alternatives on population fatty acid intakes, plasma lipids, and cardiovascular disease (CVD) risk. Using the National Health and Nutrition Examination Survey 24‐hour dietary recalls for 1999–2002, we selected 25 food categories, accounting for 86 % of soybean oil (SBO) and 79 % of TFA intake for replacement modeling. Before modeling, those in the middle quintile had a mean PHSBO TFA intake of 1.2 % of energy. PHSBO replacement in applications requiring thermal stability by either low‐linolenic acid SBO or mid‐oleic, low‐linolenic acid SBO decreased TFA intake by 0.3 % of energy and predicted CVD risk by 0.7–0.8 %. PHSBO replacement in applications requiring functional properties with palm‐based oils reduced TFA intake by 0.8 % of energy, increased palmitic acid intake by 1.0 % of energy, and reduced predicted CVD risk by 0.4 %, whereas replacement with fully hydrogenated interesterified SBO reduced TFA intake by 0.7 % of energy, increased stearic acid intake by 1.0 % of energy, and decreased predicted CVD risk by 1.2 %. PHSBO replacement in both thermal and functional applications reduced TFA intake by 1.0 % of energy and predicted CVD risk by 1.5 %. Based solely on changes in plasma lipids and lipoproteins, all PHSBO replacement models reduced estimated CVD risk, albeit less than previously reported using simpler replacement models.
Aguaribay and Cedron Essential Oils as Natural Antioxidants in Oil‐Roasted and Salted Peanuts
Authors: Olmedo Rubén H. , Nepote Valeria , Grosso Nelson R. 
Published: August 2012

AbstractThe study objective was to evaluate the antioxidant effect of aguaribay and cedron essential oils on oil‐roasted and salted peanuts. Fried‐salted peanuts (FP), fried‐salted peanuts with addition of BHT (FP‐BHT) aguaribay (FP‐A) and cedron (FP‐C) essential oils were prepared. Peroxide (PV) and p‐anisidine (AV) values, conjugated dienes (CD) and sensory descriptive attributes were analyzed on the products during storage. The major compounds detected were 25.6 % spathulenol and 24.4 % geranial and 27.3 % neral in cedron essential oils and 12.7 % elemol, 11.7 % α‐pinene, 9.3 % β‐pinene, 8.3 % limonene and 8.2 % α‐phellandrene in aguaribay essential oil. PV, AV and CD were lower in FP‐BHT during storage. At storage day 112, PVs were 94.86, 82.74, 76.29, and 63.89 mequiv O2 kg−1 in FP, FP‐A, FP‐C and FP‐BHT, respectively. FP‐C and FP‐A had lipid oxidation values between FP and FP‐BHT. The intensity ratings of oxidized and cardboard flavors increased more in the control sample (FP) than the other samples. At storage day 112, FP‐A, FP‐BHT and FP‐C exhibited oxidized intensity ratings of 24.13, 24.9 and 26.1, respectively, lower than FP (35.83). Aguaribay and cedron essential oils showed protective effect against lipid oxidation in fried‐salted peanuts. However, these essential oils could affect the sensory profile and consumer acceptance of this product.