bluuebunny/crossref_metadata_2025_split huggingface dataset:
Characterization of crystalline defects in silicon for SOI applications by means of light scattering tomography
Authors: Kononchuk Oleg , Monier Vanessa , Capello Luciana , Pichaud Bernard 
Published: June 2009

AbstractCapabilities of LST technique to study defects in silicon wafers for SOI applications are reviewed. Hardware modifications required for quantitative defect size analysis are presented together with novel calibration procedure based on HF inspection of SOI wafers. Examples of LST sensitivity to different types of the defects are demonstrated. Theoretical predictions of dislocation light scattering dependence on polarization have been confirmed allowing determination of dislocation's Burger's vector from LST measurements. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Dislocation nucleation in heteroepitaxial semiconducting films
Authors: Pichaud B. , Burle N. , Texier M. , Alfonso C. , Gailhanou M. , Thibault‐Pénisson J. , Fontaine C. , Vdovin V. I. 
Published: June 2009

AbstractThe nucleation of dislocation in semiconductors is still a matter of debate and especially in heteroepitaxial films. To understand this nucleation process the classical models of dislocation nucleation are presented and criticized. Two main points are then developed: emission of dislocations from surface steps and the role of point defects agglomeration on dislocation nucleation. Recent atomic simulation of half loops emission from surface steps and experimental evidences of anisotropic relaxation of GaInAs films deposited on vicinal (111) GaAs substrates strongly support surface steps as preferential sites for nucleation. In low temperature buffer layer structures (SiGe/Si) an original dislocation structure is observed which corresponds to the dislocation emission in different glide systems by a unique nucleation centre. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Structure, chemistry and electrical properties of extended defects in crystalline silicon for photovoltaics
Authors: Seibt M. , Abdelbarey D. , Kveder V. , Rudolf C. , Saring P. , Stolze L. , Voß O. 
Published: June 2009

AbstractThe electronic properties of present‐day multicrystalline silicon (mc‐Si) materials for photovoltaic applications are strongly influenced by point defects, their mutual interaction and their interaction with dislocations and grain boundaries. This paper presents results from fundamental investigations of metal impurity interaction with extended defects, namely a small‐angle grain boundary and bulk microdefects. It is shown that the distribution of copper silicide precipitates closely follows the density of bulk microdefects indicating the underlying physics of ‘good’ and ‘bad’ grains frequently observed in mc‐Si. Co‐precipitation of copper and nickel in the same samples leads to virtually the same distribution of multimetal silicide precipitates which according to light‐beam induced current measurements show the same recombination activity as single‐metal silicide particles. Transmission electron microscopy is used to show that for copper‐rich and nickel‐rich conditions two types of silicides co‐exist, i.e. Cu3Si precipitates containing a small amount of nickel and NiSi2 precipitates containing some copper. Finally, phosphorus‐diffusion gettering (PDG) is discussed as the main gettering process used in presentday silicon photovoltaics. Special emphasis is put on the effect of extended defects and their interaction with metal impurities on PDG kinetics. It is shown that different limiting processes will be simultaneously operative in mc‐Si as a result of inhomogeneous bulk defect distributions (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Can molecular quantum descriptors predict the butene selectivity in nickel(II) catalyzed ethylene dimerization? A QSPR study
Authors: Tognetti Vincent , Fayet Guillaume , Adamo Carlo 
Published: June 2009

AbstractIn this article, we assess the ability of common molecular descriptors issued from quantum chemistry calculations (geometrical parameters, atomic charges, isodesmic energies, polarizabilities, and descriptors from conceptual DFT) to predict the butene selectivity in the mixed (P,N)‐nickel(II) catalyzed ethylene dimerization process. To this aim, 29 active species are considered, characterized by different substitution patterns on the nitrogen and phosphorus atoms. For each of them, the Gibbs energy difference between the transition states for the third ethylene insertion and for the butene elimination is computed to characterize the selectivity. Our results show that, in contrast to previously reported catalysts, the studied descriptors did not show any significant correlations with the property to predict and their integration in a multivariate analysis was not more efficient for the considered catalytic systems. © 2009 Wiley Periodicals, Inc. Int J Quantum Chem, 2010
Spatially ordered surfactant assemblies in the gas phase: negatively charged bis(2‐ethylhexyl)sulfosuccinate‐alkaline metal ion aggregates
Authors: Giorgi Gianluca , Giocaliere Elisa , Ceraulo Leopoldo , Ruggirello Angela , Liveri Vincenzo Turco 
Published: June 2009

AbstractThe formation and structural features of negatively charged aggregates of sodium bis(2‐ethylhexyl)sulfosuccinate (AOTNa) surfactant molecules in the gas phase have been investigated by electrospray ionization mass spectrometry (ESI‐MS) and density functional theory calculations. Mainly driven by the interactions of alkali metal ions both with the oxygen atoms of the sulfonate group and with the succinate moiety of the AOT− anion, spatially ordered supramolecular assemblies, characterized by an internal core composed of surfactant counterions and hydrophilic head groups surrounded by the surfactant alkyl chains pointing outwards, are formed. Calculations have shown that surfactant self‐organization in the gas phase is energetically favoured, the energy of formation of negatively charged aggregates from isolated AOTNa and AOT− being linearly related to the aggregation number. Information on the chelating properties of AOTNa towards clusters of inorganic salts was achieved by infusion of solutions at various AOTNa/metal salt (NaCl, NaBr, NaI, LiI, KCl, CsI, RbI) ratios in the ESI source of a mass spectrometer. A wide variety of negatively charged AOT‐metal aggregates, some of them also incorporating halide (X−) ions, has been observed. Calculations have shown that the capture of a halide anion to give the AOTMX− species is favoured but the energetics of the process depends on the alkali metal and halide types. The use of energy‐resolved mass spectrometry has allowed us to evaluate the stability of different complexes and to evaluate the role played by the metal ion. Overall, the present investigation supports the idea that, in the gas phase, mainly driven by electrostatic interactions, surfactant molecules are present as molecular aggregates characterized by a reverse micelle‐like organization with an internal core formed by the surfactant counterions and head groups surrounded by the surfactant alkyl chains. These peculiar aggregates are able to incorporate ionic clusters in their hydrophilic core. Copyright © 2009 John Wiley & Sons, Ltd.
Stable isotope ratio analysis to differentiate temporal diets of a free‐ranging herbivore
Authors: Walter W. D. , Leslie D. M. 
Published: June 2009

AbstractStable isotope ratio analysis (SIRA) of carbon (δ13C) and nitrogen (δ15N) in tissue samples of herbivores can identify photosynthetic pathways (C3 vs. C4) of plants consumed. We present results from free‐ranging Rocky Mountain elk (Cervus elaphus) that highlight the ability to differentiate diets using tissue δ13C and δ15N. The signatures of δ13C and δ15N differed in tissues of varying metabolic activity: muscle, a short‐term dietary indicator (i.e., 1–2 months) and hoof, a long‐term dietary indicator (i.e., 3–12 months). We also documented that δ13C and δ15N values along elk hooves (proximal, middle, distal sections) elucidated temporal shifts in dietary selection. The carbon isotopes of the composite hoof were similar to those of the middle section, but the composite hoof differed in δ13C from the distal and proximal sections. The δ13C and δ15N signatures also differed among elk populations, indicating temporal dietary shifts of individuals occupying disparate native range and human‐derived agricultural landscapes. Analyses of stable isotopes in various tissues highlighted carbon and nitrogen assimilation through time and differences in the foraging ecology of a rangeland herbivore. Published in 2009 by John Wiley & Sons, Ltd.
A communication efficient probabilistic algorithm for mining frequent itemsets from a peer‐to‐peer network
Authors: Datta Souptik , Kargupta Hillol 
Published: June 2009

AbstractData intensive large‐scale distributed systems like peer‐to‐peer (P2P) networks are becoming increasingly popular where centralization of data is impossible for mining and analysis. Unfortunately, most of the existing data mining algorithms work only when data can be accessed in its entirety. Finding all the network‐wide frequent itemsets is computationally difficult and usually has large communication overhead in such environment. This paper focuses on developing a communication efficient algorithm for discovering frequent itemsets from a P2P network. A sampling‐based approach is adopted to find approximate solution instead of an exact solution with probabilistic guarantee. The benefit of approximation technique is reflected in the low communication overhead in discovering majority of frequent itemsets with probabilistic guarantee. The main principal followed by the algorithm assumes that an independent and identically distributed (iid) sample of the entire data is available at one location to generate a set of candidate itemsets. Collecting iid sample from a P2P network is a challenging problem because of varying degrees of connectivity and sizes of data shared. The paper first addresses this issue and shows how an iid sample of nodes and data can be collected from a P2P network using random walk. It applies the proposed sampling technique to identify most of the frequent itemsets from a P2P network. Theoretical analysis shows how to decide about optimum sample size and minimize communication to compute the results. Experimental results show that the proposed algorithm discovers all of the network‐wide frequent itemsets using communication that scales sublinearly with network and datasize. © 2009 Wiley Periodicals, Inc. Statistical Analysis and Data Mining 2: 48‐69, 2009
Meaning making through multiple modalities in a biology classroom: A multimodal semiotics discourse analysis
Authors: Jaipal Kamini 
Published: June 2009

AbstractThe teaching of science is a complex process, involving the use of multiple modalities. This paper illustrates the potential of a multimodal semiotics discourse analysis framework to illuminate meaning‐making possibilities during the teaching of a science concept. A multimodal semiotics analytical framework is developed and used to (1) analyze the semiotic and epistemological meanings communicated by multiple modalities during the teaching of a biology concept and (2) highlight features of semiotic modalities that extend meaning‐making opportunities in science classrooms. The classroom discourse of a Grade 11 biology teacher was analyzed during the teaching of the concept chemosynthesis. Data were drawn from lesson transcripts, observational fieldnotes, and informal interviews with the teacher. The findings showed that the multimodal semiotics framework was useful at illustrating how semiotic and epistemological functions of modalities compounded meanings. Most significantly, an emergent multimodal framework relating semiotic functions and science learning outcomes emerged that has the potential to (1) act as a metacognitive tool for teachers to select, sequence, and scaffold modalities and (2) act as an analytical framework for educational researchers to analyze meaning making in science teaching and learning. © 2009 Wiley Periodicals, Inc. Sci Ed 94:48–72, 2010
Swift heavy ion induced effects at Mo/Si interface and silicide formation
Authors: Agarwal Garima , Kulshrestha Vaibhav , Jain Rajkumar , Kabiraj D. , Sulania Indra , Kulriya Pawan , Jain I. P. 
Published: June 2009

AbstractSwift heavy ion (SHI) induced modification at metal/Si interfaces has emerged as an interesting field of research due to its large applications. In this study, we investigate SHI‐induced mixed molybdenum silicide film with ion fluences. The molybdenum thin films were deposited on silicon substrates using e‐beam evaporation at 10−8 torr vacuum. Thin films were irradiated with Au ions of energy 120 MeV to form molybdenum silicide. The samples were characterized by grazing incidence X‐ray diffraction (GIXRD) technique for the identification of phase formation at the interface. Rutherford backscattering spectrometry (RBS) was used to investigate the elemental distribution in the films. The mixing rate calculations were made and the diffusivity values obtained lead to a transient melt phase formation at the interface according to thermal spike model. Irradiation‐induced effects at surface have been observed and roughness variations at the surface were calculated using atomic force microscopy (AFM) technique. Copyright © 2009 John Wiley & Sons, Ltd.
Confined Assembly of Asymmetric Block‐Copolymer Nanofibers via Multiaxial Jet Electrospinning
Authors: Kalra Vibha , Lee Jung Hun , Park Jay Hoon , Marquez Manuel , Joo Yong Lak 
Published: June 2009

AbstractMultiaxial (triaxial/coaxial) electrospinning is utilized to fabricate block copolymer (poly(styrene‐b‐isoprene), PS‐b‐PI) nanofibers covered with a silica shell. The thermally stable silica shell allows post‐fabrication annealing of the fibers to obtain equilibrium self‐assembly. For the case of coaxial nanofibers, block copolymers with different isoprene volume fractions are studied to understand the effect of physical confinement and interfacial interaction on self‐assembled structures. Various confined assemblies such as co‐existing cylinders and concentric lamellar rings are obtained with the styrene domain next to the silica shell. This confined assembly is then utilized as a template to guide the placement of functional nanoparticles such as magnetite selectively into the PI domain in self‐assembled nanofibers. To further investigate the effect of interfacial interaction and frustration due to the physically confined environment, triaxial configuration is used where the middle layer of the self‐assembling material is sandwiched between the innermost and outermost silica layers. The results reveal that confined block‐copolymer assembly is significantly altered by the presence and interaction with both inner and outer silica layers. When nanoparticles are incorporated into PS‐b‐PI and placed as the middle layer, the PI phase with magnetite nanoparticles migrates next to the silica layers. The migration of the PI phase to the silica layers is also observed for the blend of PS and PS‐b‐PI as the middle layer. These materials not only provide a platform to further study the effect of confinement and wall interactions on self‐assembly but can also help develop an approach to fabricate multilayered, multistructured nanofibers for high‐end applications such as drug delivery.
Increased expression of the NR2A NMDA receptor subunit in the prefrontal cortex of rats reared in isolation
Authors: Turnock‐Jones Julia J. , Jennings Carol A. , Robbins Melanie J. , Cluderay Jane E. , Cilia Jackie , Reid Juliet L. , Taylor Adam , Jones Declan N.C. , Emson Piers C. , Southam Eric 
Published: June 2009

AbstractA hypofunction of the N‐methyl‐D‐aspartate (NMDA) receptor has been implicated in the pathophysiology of schizophrenia. Compelling evidence of altered NMDA receptor subunit expression in the schizophrenic brain has not, however, so far emerged. Rats reared in isolation exhibit several characteristics, including disturbed sensory gating, which resemble those seen in schizophrenia. To explore the possibility that NMDA receptor dysfunction may contribute to the behavioral and neurochemical consequences of rearing rats in isolation, we compared NMDA receptor subunit expression in brains of rats which were housed in isolation and which displayed a deficit in prepulse inhibition of the acoustic startle response with that of socially housed controls. An initial microarray analysis revealed a 1.26‐fold increase in NR2A transcript in the prefrontal cortex, but not in the nucleus accumbens, of rats reared in isolation compared with those housed socially. In contrast, NR1, NR2B, NR2C, NR2D, NR3A, and NR3B subunit expression was unchanged in either brain area. In a second cohort of animals, in situ hybridization revealed increased NR2A mRNA expression in the medial prefrontal cortex, an observation that was substantiated by increased [3H]CGP39653 binding suggesting that NR2A receptor subunit protein expression was also elevated in the medial prefrontal cortex of the same animals. No changes in expression of NR1 or NR2B subunits were observed at both mRNA and protein level. Altered NR2A subunit expression in the medial prefrontal cortex of rats reared in isolation suggests that NMDA receptor dysfunction may contribute to the underlying pathophysiology of this preclinical model of aspects of schizophrenia. Synapse 63:836–846, 2009. © 2009 Wiley‐Liss, Inc.
Avulsion of the Hamstring Muscle Group: A Follow‐Up of 6 Adult Non‐Athletes with Early Operative Treatment: A Brief Report
Authors: Mica Ladislav , Schwaller Adrian , Stoupis Christoferos , Penka Igor , Vomela Jindřich , Vollenweider Andreas 
Published: June 2009

AbstractBackgroundComplete proximal avulsions of the hamstring muscle group may cause significant morbidity and loss of function. These pelvis‐near musculoskeletal injuries are mostly acquired during sports activities in a hip flexion and knee extension. Here we present a study group of 6 middle‐aged to elderly patients suffering a complete proximal hamstring avulsion and following early surgical refixation. Early surgical refixation leads to complete resumption of the activities of daily life without loss of function.Materials and methodsThe 6 patients (3 men and 3 women) included in this study had an average age of 59.07 ± 4.47 years at the time of injury. All of them suffered a complete avulsion of the hamstring muscle group. Surgical refixation was accomplished with the corkscrew anchor refixation system (Arthrex Manufacturing, Inc., Naples, FL). The cases were retrospectively analyzed using a hip joint evaluation system, the Harris Hip Score, and radiological follow‐up by magnetic resonance imaging (MRI). Data are given as mean ± SEM. Student’s t‐test was used for normal distribution of the data.ResultsThe mean follow‐up time was 31.83 ± 18.9 months (range: 10–118 months). All patients were rated not to have a significant difference in function compared with the uninjured side. None of the patients suffered any handicaps resulting from surgery or the injury. A complete consolidation in all patients was observed in the follow‐up MRI.ConclusionsEarly surgical intervention and subsequent therapy in a complete hamstring avulsion injury may prevent loss of hip‐joint stability and prevent the sequalae of degradative hip or vertebral events.
Parental Engagement and Barriers to Participation in a Community‐Based Preventive Intervention
Authors: Mendez Julia L. , Carpenter Johanna L. , LaForett Doré R. , Cohen Jeremy S. 
Published: June 2009

AbstractThis study examined parent characteristics and barriers to participation in a community‐based preventive intervention with a sample of 201 parents from low‐income and predominantly ethnic minority backgrounds. Person‐centered analyses revealed five subgroups of parents who demonstrated variability in their parent characteristics, which included psychological resources and level of parental involvement in education. Group membership was associated with differences in school involvement and use of the psychoeducational intervention at home, after accounting for the number of barriers to engagement. For the intervention attendance variable, greater number of barriers was associated with decreased attendance only for parents in the resilient subgroup and the psychologically distressed subgroup. Attendance remained constant across levels of barriers for the other three subgroups of parents. The results of the study inform theory and practice regarding how to tailor preventive interventions to accommodate subgroups of parents within populations that experience barriers to accessing mental health services.
The Role of Lay Health Advisors in Cardiovascular Risk Reduction: A Review
Authors: Fleury Julie , Keller Colleen , Perez Adriana , Lee Sarah M. 
Published: June 2009

AbstractInterventions are needed to reduce the negative impact of cardiovascular disease. The combination of health risks for disease, disability, and mortality, particularly among underserved populations, might be best addressed with programs designed to enhance awareness and development of resources within a context of community support. The objectives of this review were to: (1) provide a comprehensive review and evaluation of the roles, evaluation, and effectiveness of LHA in community‐based programs with an emphasis on cardiovascular risk reduction; and (2) provide recommendations for future research involving LHA in such programs. Computer and manual searches were conducted of articles in the English‐language literature from 1980 to 2007. Twenty articles were evaluated, which emphasized the role of the LHA in cardiovascular risk reduction. A review of research literature provides a starting point for determining salient approaches for intervention and evaluation, issues related to program implementation and sustainability, and strengths and limitations of existing approaches.
Determining Ethyl Esters in Fish Oil with Solid Phase Microextraction and GC–MS
Authors: Sullivan Jenna C. , Budge Suzanne M. , St‐Onge M. 
Published: June 2009

AbstractThe long‐chain polyunsaturated fatty acids (PUFA) found in fish oil, specifically eicosapentanoic acid (EPA) and docosahexanoic acid (DHA) play an important part in human health. As a result, fish oil supplements are commonly consumed by people around the world. Supplements in the form of triacylglycerols (TAG) can be sold at a premium price, compared to those in the ethyl ester (EE) forms. Producers of TAG supplements require a simple, rapid method to determine the authenticity of their raw material. Here, we describe a method to quantify EE in fish oil using solid phase microextraction headspace analysis and GCMS. Despite the variation in linear ranges of the calibration curves with volatility of the EE, 30 individual FA were quantified including common saturated FA such as palmitic and stearic acid, as well as longer chain PUFA, such as EPA and DHA. The method was then applied to three commercial fish oils in the TAG form and two of the products were found to contain EE, with one containing EE above 1.5% w/w, indicating that contamination had occurred. With growing consumer interest in fish oil products, the method proposed here will help resolve future issues of authenticity in fish oils.
Dark and grey electromagnetic electron-cyclotron envelope solitons in an electron-positron magnetoplasma
Authors: SHUKLA P. K. , BINGHAM R. , PHELPS A. D. R. , STENFLO L. 
Published: June 2009

AbstractWe present an investigation of the amplitude modulation of an external magnetic field-aligned right-hand circularly polarized electromagnetic electron-cyclotron (EMEC) wave in a strongly magnetized electron-positron plasma. It is shown that the dynamics of the modulated EMEC wave packet is governed by a cubic nonlinear Schrödinger equation. The latter reveals that a modulated wave packet can propagate in the form of either a dark or a grey envelope soliton. This result could have relevance to the transport of electromagnetic wave energy over long distances via envelope solitons in the magnetospheres of pulsars and magnetars.