bluuebunny/crossref_metadata_2025_split huggingface dataset:
Modification of epoxy–anhydride thermosets using a hyperbranched poly(ester‐amide): I. Kinetic study
Authors: Fernández‐Francos Xavier , Rybak Andrzej , Sekula Robert , Ramis Xavier , Serra Angels 
Published: May 2012

AbstractAn epoxy‐anhydride formulation used for the coating of electrical devices was modified with a commercially available hyperbranched poly(ester‐amide), Hybrane™ S2200, in order to improve the thermal degradability of the resulting thermoset and thus facilitate the recovery of substrate materials after use of the component. The curing kinetics of the unmodified and modified formulations were studied in detail with differential scanning calorimetry, Fourier transform infrared spectroscopy and rheology. The results suggest that S2200 gets incorporated into the network structure and the curing kinetics are accelerated by the presence of hydroxyl groups from S2200. Copyright © 2012 Society of Chemical Industry
Calculation of Particle Size Distributions from Ultrasonic Measurements: A Mineral Slurry Case Study
Authors: Coghill Peter John , Millen Michael 
Published: May 2012

AbstractUltrasonic transmission measurements have been used extensively to determine the particle size of solids in slurries. This case study examines the application of mathematical inversion techniques to the determination of the particle size distribution of a mineral slurry from data collected at a minerals processing plant. A new mathematical inversion technique, based on an extension of modified Chahine iteration combined with the principle of maximum entropy has been developed. Four algorithms were constructed and used to calculate particle size distributions from synthetic and raw plant data. These incorporated modified Chahine iteration and its extension, together with two different approaches to applying a density measurement constraint on the particle size distribution. In general the algorithms performed well with regression errors below 3 %. The correlation coefficients and slopes for this technique were 0.86 and 1.35 for the weight fraction of particles less than 75 microns when compared with the laser diffraction analysis. A better match was obtained for the plant data by using the new inversion technique, into which the principle of maximum entropy has been incorporated whereas this was not the case with the synthetic data, illustrating the need to match the inversion technique to the problem.
Random Packing of Small Blocks: Pressure Effects, Orientational Correlations and Application to Polymer‐Based Composites
Authors: Sergi Danilo , D'Angelo Claudio , Scocchi Giulio , Ortona Alberto 
Published: May 2012

AbstractPacking is a complex phenomenon of prominence in many natural and industrial processes (liquid crystals, granular materials, infiltration, melting, flow, sintering, segregation, sedimentation, compaction, etc.). A variety of computational methods is available in particular for spheroid particles. Our aim is to apply the principle of the random sequential addition algorithm but with small blocks of varying size and orientation. Here the main purpose is to reproduce the observed arrangement of graphitic assemblies in polymeric matrices. Random packing is improved by applying an external pressure implemented with a drifted diffusive motion of the fillers. Attention is also paid to the emergence of structural and orientational order. Interestingly, mixtures of fillers of irregular shapes can be dealt with efficiently using the proposed algorithm.
Sequence‐dependent backbone dynamics of a viral fusogen transmembrane helix
Authors: Stelzer Walter , Langosch Dieter 
Published: May 2012

AbstractThe transmembrane domains of membrane fusogenic proteins are known to contribute to lipid bilayer mixing as indicated by mutational studies and functional reconstitution of peptide mimics. Here, we demonstrate that mutations of a GxxxG motif or of Ile residues, that were previously shown to compromise the fusogenicity of the Vesicular Stomatitis virus G‐protein transmembrane helix, reduce its backbone dynamics as determined by deuterium/hydrogen‐exchange kinetics. Thus, the backbone dynamics of these helices may be linked to their fusogenicity which is consistent with the known over‐representation of Gly and Ile in viral fusogen transmembrane helices. The transmembrane domains of membrane fusogenic proteins are known to contribute to lipid bilayer mixing. Our present results demonstrate that mutations of certain residues, that were previously shown to compromise the fusogenicity of the Vesicular Stomatitis virus G‐protein transmembrane helix, reduce its backbone dynamics. Thus, the data suggest a relationship between sequence, backbone dynamics, and fusogenicity of transmembrane segments of viral fusogenic proteins.
Designing specific protein–protein interactions using computation, experimental library screening, or integrated methods
Authors: Chen T. Scott , Keating Amy E. 
Published: May 2012

AbstractGiven the importance of protein–protein interactions for nearly all biological processes, the design of protein affinity reagents for use in research, diagnosis or therapy is an important endeavor. Engineered proteins would ideally have high specificities for their intended targets, but achieving interaction specificity by design can be challenging. There are two major approaches to protein design or redesign. Most commonly, proteins and peptides are engineered using experimental library screening and/or in vitro evolution. An alternative approach involves using protein structure and computational modeling to rationally choose sequences predicted to have desirable properties. Computational design has successfully produced novel proteins with enhanced stability, desired interactions and enzymatic function. Here we review the strengths and limitations of experimental library screening and computational structure‐based design, giving examples where these methods have been applied to designing protein interaction specificity. We highlight recent studies that demonstrate strategies for combining computational modeling with library screening. The computational methods provide focused libraries predicted to be enriched in sequences with the properties of interest. Such integrated approaches represent a promising way to increase the efficiency of protein design and to engineer complex functionality such as interaction specificity.
Alpha methylacyl‐CoA racemase (AMACR) in prostate adenocarcinomas from Japanese patients: Is AMACR a “race”‐dependent marker?
Authors: Yamada Hiroshi , Tsuzuki Toyonori , Maeda Nagako , Yamauchi Yushi , Yoshida Shinri , Ishida Ryo , Nishikimi Toshinori , Yokoi Keisuke , Kobayashi Hiroaki 
Published: May 2012

AbstractBACKGROUNDAlpha methylacyl‐CoA racemase (AMACR) is a useful diagnostic marker for prostate adenocarcinoma. However, its usefulness has not been fully validated in Japanese patients. The aim of this study was to evaluate the diagnostic utility of AMACR in prostate needle biopsy examination in Japanese patients.METHODSA total of 119 prospective consecutive prostate needle biopsy specimens (680 cores) obtained from Japanese patients were examined. Sixty patients had adenocarcinoma (adenocarcinoma, 160 cores; benign, 204 cores), 14 patients had high‐grade prostatic intraepithelial neoplasia (HGPIN; 19 cores), and 45 patients did not have any neoplastic lesions (297 cores). AMACR expression was scored semi‐quantitatively as 0 (no expression), 1+ (partial and/or weak expression), or 2+ (strong, circumferential expression). The number of positively stained glands was counted.RESULTS2+ AMACR expression was observed in 70.1% of adenocarcinoma cases and in 52.6% of HGPIN cases. Of the adenocarcinoma cases showing 2+ AMACR expression, 34.8% demonstrated a heterogeneous expression pattern, with 1–75% of AMACR‐positive glands. Three hundred eighty‐five of the benign glands with an adenocarcinoma component showed 2+ AMACR expression (35 cases, 94 cores). 2+ AMACR expression was observed in 67 non‐neoplastic benign glands (9 cases, 19 cores).CONCLUSIONSThe sensitivity and specificity of AMACR for the diagnosis of prostate adenocarcinoma and benign glands in Japanese patients are lower than those previously reported in Western countries. Pathologists should be cautious while interpreting AMACR expression pattern in Japanese patients. Prostate 73: 54–59, 2013. © 2012 Wiley Periodicals, Inc.
Differential tunability effect on the optical properties of doped and undoped quantum dots
Authors: Gogoi Madhulekha , Deb Pritam , Kostka Aleksander 
Published: May 2012

AbstractWe have studied the optical properties of size‐tunable undoped and Mn2+‐doped cadmium telluride (CdTe) quantum dots (QDs) of monodisperse suspensions with emission wavelength varying between 500 and 680 nm. The role of the surface is investigated for obtaining size‐tunable, bright, and stable CdTe QDs. Differentially tunable optical properties of doped and undoped CdTe QDs has been reported. Unlike the continuous redshifting in the absorption spectra of pristine CdTe system, an unusual blueshift is observed for doped CdTe system after a certain time period of refluxion, followed by again a redshift and the disappearance of earlier peak with further refluxing. The available size range and optical properties are significantly controlled through Mn2+ doping. The surface adsorbed Mn promotes ripening of the doped system as well as disintegration into smaller fraction after saturation in growth occurs. An optimum size fraction is identified for both the systems based on their photoluminescence (PL) quantum yield. The photophysics of Mn2+‐doped nanocrystals has been proposed.
Complex hierarchical arrangements of stacked nanoplates in Al‐doped ZnO
Authors: Ortega Y. , Häussler D. , Piqueras J. , Fernández P. , Jäger W. 
Published: May 2012

AbstractAl‐doped micro‐ and nanostructures have been grown by an evaporation–deposition method with a mixture of ZnS and Al2O3 powders as precursor. It has been found that the presence of Al is the cause of the growth of complex morphologies, as rods formed by stacks of nanoplates and other complex hierarchical structures. The role of Al in the growth process has been investigated by electron microscopy techniques. Al‐rich particles in specific sites of a central rod lead to hierachical growth. Transmission electron microscopy shows that in some cases the Al‐rich zones are clusters of spinel ZnAl2O4 nanoparticles adhered to ZnO nanorods. Al incorporation into the structures and the dopant effect on the luminescence behavior of the ZnO structures were investigated by energy dispersive spectroscopy and by cathodoluminescence.
Transition voltage spectroscopy in vacuum break junction: The standard tunneling barrier model and beyond
Authors: Bâldea Ioan , Köppel Horst 
Published: May 2012

AbstractRecent experiments on transition voltage (Vt) spectroscopy in mechanically controllable vacuum break junctions have been interpreted theoretically by using a Simmons WKB‐type approach of the transport by tunneling based on the standard vacuum barrier picture (work function + source‐drain bias + charge images). In the first part of the paper, we present an analysis demonstrating the inconsistencies of that approach. Then, we report detailed results obtained by exactly solving the Schrödinger equation, which show that the standard tunneling barrier model fails to describe the experimental vacuum transition voltage spectroscopy (TVS) data. This indicates that the physical description within that model is incomplete. In the attempt to go beyond the standard barrier model, we report results demonstrating that the inclusion of electron states at the electrodes' surface significantly improves the agreement with experiment. This applies both to the d‐dependence of Vt and to the jump in the linear conductance when approaching the atomic contact limit.
Influence of Ni doping on the electrical and structural properties of FeSb2
Authors: Janaki J. , Mani Awadhesh , Satya A. T. , Kumary T. Geetha , Kalavathi S. , Bharathi A. 
Published: May 2012

AbstractThe influence of increasing Ni doping on the structural and magneto‐transport properties of FeSb2 have been investigated by synthesizing Fe1−xNixSb2 samples with x = 0–0.4 using solid‐state reaction method. The samples are single phase from x = 0–0.1 with the marcasite (FeS2)‐type structure. Beyond x > 0.2 the skutterudite (CoAs3)‐type phase starts progressively separating out apart from the required marcasite phase. The temperature‐dependent electrical resistivity studies in the range 4.2–300 K reveal activation behavior in the high‐temperature (HT) regime (T > 70 K) with a narrow gap. The gap value increases with Ni content x. In contrast, a variable‐range hopping (VRH) type transport is seen in the low‐temperature (LT) regime. The VRH parameter T0 progressively diminishes with increasing x. A detailed analysis of magnetoresistance using the Shklovskii–Efros model in the VRH regime indicates the increase of localization length with increasing Ni content. An insulator to metal transition is observed in the LT regime for x = 0.1. This is ascribed to arise on account of delocalization of localized states within the gap.
Modeling complex systems of systems with Phantom System Models
Authors: Haimes Yacov Y. 
Published: May 2012

AbstractComplex systems are commonly composed of interconnected and inter‐ and intradependent subsystems, which in their essence constitute systems of systems with multiple functions, operations, and stakeholders. Phantom System Models (PSM) is a modeling methodology inspired by philosophical and conceptual thinking from the arts, and is driven and supported by systems engineering theory, methodology, and practice. The PSM is designed to model inter‐ and intradependencies between and among the subsystems of a complex system of systems by exploiting vital knowledge and information embedded in the intrinsic and extrinsic common and uncommon state variables among the subsystems. Among the several systems engineering theories and methodologies, the PSM in particular builds on the centrality of the states of the system in modeling and in risk analysis; fundamentals in system identification (the inverse problem); hierarchical holographic modeling; coordinated hierarchical Bayesian model; and hierarchical decomposition and higher‐level coordination. An example problem of a PSM‐based modeling of a prototype system of systems is presented. © 2012 Wiley Periodicals, Inc. Syst Eng
Treatment of a Methylene‐Bridged Dialuminium Compound with Lithium Alkanides and Alkynides ‐ Single vs. Twofold Terminal Coordination
Authors: Uhl Werner , Rösener Christian , Layh Marcus , Hepp Alexander 
Published: May 2012

AbstractWe have investigated the coordination of alkanide and alkynide anions to the coordinatively unsaturated aluminium atoms of the methylene‐bridged dialuminium compound R2Al‐CH2‐AlR2 [1, R = CH(SiMe3)2]. Treatment of 1 with the corresponding lithium derivatives in the presence of a small excess of TMEN (TMEN = tetramethylethylenediamine) yielded mono‐adducts [M]+[R2Al‐CH2‐AlR2R']– [2a, M = Li(TMEN)2, R' = Me; 2b, M = Li(TMEN)2, R' = n‐Bu; 3a, M = Li(TMEN)2, R' = C≡C‐SiMe3; 3b, M = Li(TMEN)2, R' = C≡C‐t‐Bu; 3d, M = Li(DME)3, R' = C≡C‐Ph; 3e, M = Li(TMEN)2, R' = C≡C‐PPh2)] and bis‐adducts [Li(TMEN)2]+[LiCH2(AlR2R')2]– [4a, R' = C≡C‐CH2‐NEt2; 4b, R' = C≡C‐t‐Bu]. In the solid state the mono‐adducts have clearly separated coordinatively saturated (coordination number four) and unsaturated aluminium atoms (coordination number three). In solution the groups R' show a fast exchange between both aluminium atoms as evident from the room temperature NMR spectra that showed in most cases equivalent CH(SiMe3)2 groups despite different coordination spheres of the metal atoms. Only 2b gave the expected splitting of resonances at ambient temperature, while cooling was required to prevent the dynamic process for 3a. The dialkynide 4a has a unique molecular structure with one of the lithium cations bonded to the α‐carbon atoms of the alkynido ligands and to the carbon atom of the methylene bridge which is five‐coordinate with a distorted trigonal bipyramidal coordination sphere.
Synthesis and X‐ray Crystal Structures of Homoleptic Zinc Complexes Containing Monoanionic β‐Ketoiminato and Bis­(thiophosphinoyl)methanediide Ligands
Authors: Schulz Stephan , Schäper Raphaela , Bläser Dieter , Wölper Christoph 
Published: May 2012

AbstractHomoleptic zinc complexes of the type L2Zn containing monoanionic β‐ketoiminate and bis(thiophosphinoyl)methanide substituents were synthesized in almost quantitative yield by reaction of HC(CMe)2(O)(N(H)CH2CH2NMe2) and H2C(PPh2=S)2 with zincocene Cp*2Zn at ambient temperature. The reactions proceeded with elimination of Cp*H. [HC(CMe)2(O)(NCH2CH2NMe2)]2Zn (1) and [HC(PPh2=S)2]2Zn (2) were characterized by NMR (1H, 13C, 31P) and IR spectroscopy as well as elemental analysis and single crystal X‐ray diffraction. 1 and 2 were also obtained in reactions of dizincocene, Cp*2Zn2, with two equivalents of the ligands. The reactions proceeded with disproportionation of initially formed monovalent dizinc complexes.
Stoichiometric traits of oriental oak (Quercus variabilis) acorns and their variations in relation to environmental variables across temperate to subtropical China
Authors: Sun Xiao , Kang Hongzhang , Du Hongmei , Hu Haibo , Zhou Jingbo , Hou Jingli , Zhou Xuan , Liu Chunjiang 
Published: May 2012

AbstractThe stoichiometric composition of plant reproductive organs varies with environmental conditions at a large geographical scale, which has potentially important consequences both for plant reproductive success and for the nutrition of consumers. In the study reported here, we investigated variations in the concentrations of macronutrients in acorns of the oriental oak (Quercus variabilis) in relation to environmental variables across a geographic gradient spanning temperate and subtropical latitudes. Across this gradient, nitrogen (N) and calcium (Ca) concentrations of the acorns had higher coefficients of variance (CV 18–23 %) than the other elements (CV 8–14 %). With increasing latitude (LAT), acorn N, potassium (K), and magnesium (Mg) concentrations increased, whereas those of sulfur (S) and Ca and the carbon:nitrogen (C:N) and S:N ratios decreased. The K and Mg concentrations of the acorns were positively correlated with the concentrations of these elements in the soil, whereas N and Ca concentrations were inversely correlated with soil concentrations. The C:N:P (phosphorus) molar ratio of the acorns was 1,008:17:1. A low temperature and short growing season stimulated seeds to accumulate more macronutrient elements in the north to ensure reproductive success, while high soil Ca in the north led plants to allocate less Ca to their acorns. The pattern of variation in acorn stoichiometric traits along LAT may be the result of interacting effects of plant reproduction strategy and environmental factors. Our results can help improve our understanding of the effects of global changes on the chemical compositions of plant reproductive organs and advance our knowledge of global patterns of ecological stoichiometry in reproductive organs.
Clinical Outcomes Analysis of Conservative and Surgical Treatment of Patients With Clinical Indications of Prearthritic, Intra‐articular Hip Disorders
Authors: Hunt Devyani , Prather Heidi , Harris Hayes Marcie , Clohisy John C. 
Published: May 2012

ObjectiveTo describe outcomes of the conservative treatment of patients who had the clinical presentation of a prearthritic, intra‐articular hip disorder, including acetabular labral tears, developmental hip dysplasia, and femoroacetabular impingement.DesignProspective observational clinical outcomes study.SettingOutpatient orthopedic clinic at a tertiary university hospital.PatientsPatients presenting with prearthritic, intra‐articular hip disorders were recruited. Fifty‐eight consecutive patients were enrolled; 6 were lost to follow‐up, and 52 subjects completed the study.MethodsPatients were recruited on the basis of symptoms, distribution of pain, and the findings of a physical examination. Radiographic measurements of the hip were obtained for all subjects to describe the presence or absence and extent of deformity and/or osteoarthritis. All subjects completed a directed course of conservative treatment. After 3 months of conservative care, subjects with continued limitations, reduction of symptoms with a diagnostic intra‐articular hip injection, and a surgically amenable lesion found on a magnetic resonance arthrogram proceeded to surgery.Main Outcome MeasurementsNumeric Pain Score (0‐10), Short Form‐12, Modified Harris Hip Score, Western Ontario and McMaster Universities Osteoarthritis Index, Nonarthritic Hip Score, Baecke Questionnaire of Habitual Activity, and patient choice to have surgery.ResultsFifty‐eight patients (9 men and 49 women) with a mean age of 35 ± 11 years (range, 18‐50 years) enrolled in the study. Fifty‐two subjects completed the study. Twenty‐three subjects (44%) reported satisfaction with conservative care. Twenty‐nine subjects (56%) chose to have surgery. Both groups demonstrated equally significant improvement (P value ranges: P = .03 to P = .0001) in all outcome measures from baseline to 1‐year follow‐up. Subjects who chose surgery had higher baseline activity scores compared with the conservative treatment group (P = .02).ConclusionAll subjects with signs and symptoms of prearthritic, intra‐articular hip disorders who were treated with conservative treatment alone and with conservative treatment followed by surgery demonstrated significant improvement in pain and functioning from baseline to 1 year. Forty‐four percent of patients improved with conservative care alone, and 56% chose to have surgery after receiving conservative care. Persons with more active lifestyles were more likely to choose surgery. These data suggest that a trial of conservative management for persons with prearthritic, intra‐articular hip disorders should be considered before engaging in surgical intervention.
Evidence for the volcanoclastic genesis of the Carnian diamondiferous bed in the Ust’-Olenek area (from petrographic and geochemical data)
Authors: Proskurnin V.F. , Vinogradova N.P. , Gavrysh A.V. , Naumov M.V. 
Published: May 2012

Abstract
A detailed petrographic study of a 0.4–1.2 m thick Carnian diamondiferous bed of the Angardam-Tasa Ridge (Ust’-Olenek area, northern Siberia) was performed. It showed that the bed earlier referred to as a terrigenous deposit might be interpreted as an intensely altered volcanoclastic lapilli tuff of basic and, probably, ultrabasic composition. The tuff occurs within a 100 m thick Ladinian–Carnian volcanosedimentary sequence. It consists mainly of resurgent material: altered lithoclasts (nodules of basic-ultrabasic? lithology), devitrified volcanic glass, fragments of autolithic breccia, etc. The thin volcanoclastic sheet is supposed to have formed within a sedimentation basin as a result of phreatomagmatic eruptions of kimberlite volcanoes. The substantiation of the volcanogenic origin of the Carnian diamondiferous bed might be a new approach to elucidate the primary source of widespread placer diamonds in Arctic Siberia.
Emotional labour and successful ageing in the workplace among older Chinese employees
Authors: CHEUNG FRANCIS , WU ANISE M. S. 
Published: May 2012

ABSTRACTIn this study, we examined the relationship between emotional labour and successful ageing among older Hong Kong Chinese workers. We also investigated whether job satisfaction mediated the association between emotional labour and successful ageing in the workplace. Results show that deep acting was positively related to successful ageing in the workplace, whereas surface acting was negatively related to the same. Structural equation modelling shows that job satisfaction partially mediated the association between emotional labour and successful ageing in the workplace. The limitations of the study and further recommendations are also discussed.