bluuebunny/crossref_metadata_2025_split huggingface dataset:
Differential surface photovoltage spectroscopy of δ‐doped GaAs/AlAs multiple quantum wells below and close to Mott transition
Authors: Kavaliauskas J. , Krivaitė G. , Čechavičius B. , Valušis G. , Seliuta D. , Sherliker B. , Halsall M. , Harrison P. , Linfield E. , Steer M. 
Published: October 2007

AbstractDifferential surface photovoltage (DSPV) spectra of Be δ‐doped GaAs/AlAs multiple quantum wells (MQWs) with doping densities below (5 × 1010 cm–2) and near (5 × 1012 cm–2) a Mott transition were studied at 300 K and 90 K. From the line shape analysis of the DSPV spectra, exhibiting obvious doping and temperature dependences, an origin of optical transitions has been revealed. The spectra of lightly doped structures were accounted for by ground state heavy and light‐hole related excitonic transitions. In highly doped GaAs/AlAs MQWs the heavy‐hole excitons were found to be quenched while rather broadened light‐hole related transitions still exhibited an excitonic character. The experimental observations suggest that with increasing doping level phase‐space filling effects dominate over Coulomb screening. The renormalization effects due to many body interactions were found to be more pronounced for the lowest heavy‐hole subband when compared to the light‐hole one. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Magnetic properties of multiferroic TbMnO3 doped with Al
Authors: Pérez F. , Heiras J. , Escudero R. 
Published: October 2007

AbstractThe synthesis, characterization, and magnetic properties of polycrystalline Tb1–xAlxMnO3 with x = 0.05 and 0.1 is reported. Samples were synthesized by the conventional solid state reaction method producing single phase compounds. Rietveld refinements indicate that Al substitutes Tb in the structure. Samples were highly porous with grain sizes up to ∼10 μm. The magnetic measurements show a magnetic ordering, starting from antiferromagnetism, for the undoped sample, to a weak ferromagnetic phase coexisting with the antiferromagnetic phase for the two x values. The magnetic ordering is attributed to two different contributions of Mn and Tb sublattices. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Hardness and wearing properties of SiO2–PMMA hybrid coatings reinforced with Al2O3 nanowhiskers
Authors: Alvarado‐Rivera J. , Muñoz‐Saldaña J. , Castro‐Beltrán A. , Quintero‐Armenta J. M. , Almaral‐Sánchez J. L. , Ramírez‐Bon R. 
Published: October 2007

AbstractSome properties of SiO2–PMMA hybrid coatings can be tailored by controlling the weight content of each component. For instance, hardness of SiO2–PMMA hybrid coatings takes values between those of SiO2 and PMMA, depending on the molar concentration ratio. Thus, these coatings are quite appropriated to be applied as antiscratch and abrasion resistant on polymeric materials such as acrylic. In this work we have evaluated the hardness and wearing properties of SiO2–PMMA‐Al2O3 hybrid coatings deposited on acrylic substrates. The hybrid coatings were deposited by the sol‐gel method from a precursor solution with a molar ratio 1:0.25:0.25 for tetraethil‐orthosilicate (TEOS), methylmethacrylate (MMA) and 3‐trimetoxi‐silil‐propil‐methacrylate (TMSPM) as the coupling agent, respectively. Another set of hybrid coatings with additional 0.1 wt.% of Al2O3 nanowhiskers in an identical precursor solution were also deposited on acrylic substrates. Hardness, creep and wearing properties of both types of hybrid coatings were evaluated by nanoindentation and nanoscratching. Complementary atomic force microscopy and optical transmission spectroscopy measurements were done in all the hybrid films studied. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Cutting tools performance enhancement by using a TiN/TiAlN multilayer coating system
Authors: Bejarano Gaitan G. , Caicedo J. C. , Balogh Adam G. , Gottschalk S. 
Published: October 2007

AbstractTiN and TiAlN monolayer as well as TiN/AlTiN multilayer were deposited by d.c. reactive magnetron sputtering using titanium and aluminum targets with 10 cm in diameter and 99.99% purity in an argon/nitrogen atmosphere, applying a substrate temperature of 300 °C and a pressure of 7 mbar. Silicon (100) and steel AISI M2 were utilized as substrate. The influence of aluminum content on the properties of TiAlN coatings was first investigated, afterwards the mechanical and tribological properties behavior of TiN/AlTiN coating were analyzed as function of multilayer number. For this purpose, the coatings chemical composition was determined by EDX spectroscopy, the crystalline structure through X‐ray diffractometry and its morphology using scanning electron microscopy. Hardness and adherence were determined by means of nanoindentation and scratch techniques respectively. Hardness increased from 18.9 GPa for 51%Al content in the TiAlN films up to 23.9 GPa for 66.7% Al. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Influence of bias voltage on the crystallographic orientation and morphology of sputter deposited yttria stabilized zirconia (YSZ) thin films
Authors: Amaya C. , Caicedo J. , Bejarano G. , Cortés Escobedo C. A. , Muñoz‐Saldaña J. , Zambrano G. , Prieto P. 
Published: October 2007

AbstractZrO2‐8% mol. Y2O3 (8YSZ) thin films were deposited onto silicon [100] and AISI 304 stainless steel substrates by r.f. (13.56 MHz) multi‐target magnetron sputtering. To improve the adhesion of a YSZ monolayer to the stainless steel substrate, a buffer layer of Al2O3 was incorporated too. Crystal structure and Infrared (IR) absorption bands of YSZ were investigated as functions of substrate bias by X‐ray diffraction (XRD) and Fourier Transformed Infrared Spectroscopy (FTIR), respectively. The influence of the bias voltage on the roughness, grain size, and microstructure of deposited thin films was determined by AFM and SEM. XRD results show the presence of a tetragonal phase with [111] and [200] orientations. On the other hand, FTIR spectra exhibit the 2Eu and F1u modes as two broad bands in the frequency range of 450 ∼ 550 cm–1 and 550 ∼ 650 cm–1, corresponding to the tetragonal and cubic phases of ZrO2, respectively. In this work we present the systematic influence of the bias voltage on the crystalline structure, the presence of the tetragonal phase and morphology of the YSZ thin films. The XRD, FTIR, and AFM results indicate that when the bias voltage increases from ‐20 V to ‐60 V the preferential crystallographic orientation of YSZ tetragonal phase changes from [111] to [200], and the percentage of the tetragonal phase diminishes, as well as the grain size of deposited films from (560 ± 5) to (470 ± 5) nm. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Nanoindentation and structural characterization of molded starch
Authors: Morin‐Alcazar S. , Muñoz‐Saldaña J. , Aguilar‐Palazuelos E. , Jímenez‐Arevalo O. , Ramírez‐Bon R. , Martínez‐Bustos F. 
Published: October 2007

AbstractStarch processed by injection molding is a good candidate to substitute inorganic polymers because of its renewable and environmental friendly characteristics. However, starch usable products show an ageing process that affects structural and mechanical properties. In this work mechanical and structural properties of extruded‐injection molded samples of corn starch prepared with 25% moisture content were characterized in “as molded”, and after ageing conditions. The microstructure and morphology of the samples were analyzed using X‐ray diffraction (XRD) and scanning electronic microscopy (SEM). Standard indentation tests as well as creep ones were performed to obtain the static elastic modulus, creep rate and hardness of the samples. Results showed that after the period of ageing the CR of the materials increased due to a crystalline reordering in the aged material. Moreover, elastic modulus and creep behavior showed a close correlation to the ageing process in the molded starch sample leading to a material with homogeneous elastic properties with the penetration depth. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Solution and solid state properties of 3,3′′′‐didodecylquaterthiophene and benzodithiophene copolymers
Authors: Jaramillo‐Isaza F. , Turner Michael L. 
Published: October 2007

AbstractThe solution and solid state properties of a library of conjugated copolymers based on dodecyl quarterthiophene (DQT) and benzodithiophene (BDT) repeating units is presented. The influence of the copolymer composition on the conjugation length and the solid state properties of these copolymers have been investigated to evaluate these materials as candidates for use in flexible organic electronic devices. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Benchmarking the Reliability of QikProp. Correlation between Experimental and Predicted Values
Authors: Ioakimidis Leukothea , Thoukydidis Loizos , Mirza Amin , Naeem Saira , Reynisson Jóhannes 
Published: October 2007

AbstractThe theoretical prediction power of the software package QikProp was tested. This was achieved by comparing experimentally known results to predicted values. First, simple molecular descriptors for physicochemical properties: octanol–water partition (log P), water solubility (log S), dipole moment, Ionisation Potential (IP) and Electron Affinity (EA) were compared to their experimentally determined counterparts. For all of the descriptors, except EA, a relatively good linear correlation was obtained. Experimentally derived EA values are relatively scarce and often quite inconsistent, which made it difficult to construct a reliable test collection. When compared to values calculated by the Density Functional Theory (DFT) method a reasonable correlation was observed but there is much room for improvement. A clear Gaussian distribution pattern was obtained when a collection of ∼470 marketed orally bioavailable drug compounds was used to generate the physicochemical properties investigated. The idea was explored whether the prediction power of ADME modules could be tested in a qualitative way, based on broad assumptions, using different classes of marketed drug compounds. It was found that this approach gives one a good idea about which modules deserve further attention for evaluation. In this way it is concluded that cell permeation and the blood–brain barrier modules merit more evaluation work whereas work on the HERG K+ and CNS activity modules was discontinued.
RobustH∞control of uncertain linear impulsive stochastic systems
Authors: Chen Wu‐Hua , Wang Jun‐Ge , Tang You‐Jian , Lu Xiaomei 
Published: October 2007

AbstractThis paper develops robust stability theorems and robustH∞control theory for uncertain impulsive stochastic systems. The parametric uncertainties are assumed to be time varying and norm bounded. Impulsive stochastic systems can be divided into three cases, namely, the systems with stable/stabilizable continuous‐time stochastic dynamics and unstable/unstabilizable discrete‐time dynamics, the systems with unstable/unstabilizable continuous dynamics and stable/stabilizable discrete‐time dynamics, and the systems in which both the continuous‐time stochastic dynamics and the discrete‐time dynamics are stable/stabilizable. Sufficient conditions for robust exponential stability and robust stabilization for uncertain impulsive stochastic systems are derived in terms of an average dwell‐time condition. Then, a linear matrix inequality‐based approach to the design of a robustH∞controller for each system is presented. Finally, the numerical examples are provided to demonstrate the effectiveness of the proposed approach. Copyright © 2007 John Wiley & Sons, Ltd.
Transmission friction in an electric mining shovel
Authors: Austin Kevin J. , McAree P. Ross 
Published: October 2007

AbstractFriction is a phenomenon present in all mechanical systems and is undesirable in estimation and control tasks. This paper explores the characteristics of friction in the transmission of an electric mining shovel, with a view to compensating for them. Experiments suggest that the transmission friction can be described by a Coulomb friction model with associated uncertainty on the friction force. The Kalman Inverse Filter is evaluated as a method for adaptively estimating the friction for motion of the bucket through free‐space. The friction estimates are consistent with experimental results. © 2007 Wiley Periodicals, Inc.
A model of work wellness for non‐professional counsellors in South Africa
Authors: Fourie Lukas , Rothmann Sebastiaan , van de Vijver Fons J. R. 
Published: October 2007

AbstractThe objective of this study was to investigate the effects of job demands, job resources and sense of coherence on the burnout and work engagement of non‐professional counsellors in South African banks. A cross‐sectional survey design was used. The sample consisted of 165 non‐professional counsellors doing trauma counselling in three of the major banks in South Africa. The Maslach Burnout Inventory—Human Services Survey, Utrecht Work Engagement Scale, Orientation to Life Questionnaire and Job Characteristics Scale were administered. A good fit was found for a model in which sense of coherence was a positive predictor of perceived low job demands and high availability of job resources and work wellness (low burnout and high work engagement). Non‐professional counsellors with a stronger sense of coherence experienced more work wellness (low burnout and high work engagement) than those with a weaker level of coherence, presumably because stimuli from the environment are perceived as making cognitive sense, as under control of both the counsellor and significant others, and as motivationally relevant and meaningful. Copyright © 2007 John Wiley & Sons, Ltd.
Hybrid strategic groups
Authors: DeSarbo Wayne S. , Grewal Rajdeep 
Published: October 2007

AbstractThe notion of strategic groups has recently emerged as a critical perspective for uncovering firms' strategic postures/recipes and competitive market structures. Firms within strategic groups generally adopt similar strategic recipes and compete more intensely than firms across strategic groups. Building on recent research, the authors develop the concept of hybrid strategic groups, which blend the strategic recipes of more than one group, in contrast to existing conceptualizations of strategic groups, where either firms tightly follow the recipes of a strategic group (i.e., core firms) or firms loosely follow the recipes of a strategic group (i.e., secondary firms). Thus, competition among firms depends not only on the strategic group but also on the overlap of that strategic group with other strategic groups. The authors devise a combinatorial optimization‐based classification procedure utilizing a bilinear model that accommodates multiple variable batteries that can estimate hybrid strategic groups. The proposed methodology is illustrated by using archival data on public banks. For this illustration, the hybrid strategic group solution outperforms ordinary cluster analyses and offers critical insights into the nature of competition among firms. Copyright © 2007 John Wiley & Sons, Ltd.
Spatial controls for growth zone formation during the fission yeast cell cycle
Authors: Csikász‐Nagy Attila , Győrffy Béla , Alt Wolfgang , Tyson John J. , Novák Béla 
Published: October 2007

AbstractBecause of its regular shape, fission yeast is becoming an increasingly important organism in the study of cellular morphogenesis. Genetic experiments with mutants and drug treatment studies with wild‐type cells have revealed the importance of microtubules in controlling new growth zone formation. It is believed that microtubules exert this role by delivering to cell ends a ‘dynamic landmark’ protein, tea1p, which promotes actin polymerization and growth zone formation. Here we present a simple model for fission yeast morphogenesis that describes the interplay between these two cytoskeletal elements. An essential assumption of the model is that actin polymerization is a self‐reinforcing process: filamentous actin promotes its own formation from globular actin subunits via regulatory molecules. In our model, microtubules stimulate actin polymerization by delivering a component of the autocatalytic actin‐assembly feedback loop (not by delivering a de novo inducer of actin polymerization). We show that the model captures all the characteristic features of polarized growth in fission yeast during normal mitotic cycles. We categorize the types of growth patterns that can exist in the model and show that they correspond to the major classes of morphogenetic mutants (monopolar, orb, banana and tea). Based on these results, we propose that fission yeast cells have specific size ranges in which they can exhibit two or more different stable patterns of growth. Copyright © 2007 John Wiley & Sons, Ltd.
Chemical Synthesis of PEDOT–Au Nanocomposite
Authors: Selvaganesh S Vinod , Mathiyarasu J , Phani KLN , Yegnaraman V 
Published: October 2007

Abstract
In this work, gold-incorporated polyethylenedioxythiophene nanocomposite material has been synthesized chemically, employing reverse emulsion polymerization method. Infrared and Raman spectroscopic studies revealed that the polymerization of ethylenedioxythiophene leads to the formation of polymer polyethylenedioxythiophene incorporating gold nanoparticles. Scanning electron microscope studies showed the formation of polymer nanorods of 50–100 nm diameter and the X-ray diffraction analysis clearly indicates the presence of gold nanoparticles of 50 nm in size.
Bridging the gap between pain and gender research: A selective literature review
Authors: Bernardes Sónia F. , Keogh Edmund , Lima Maria Luísa 
Published: October 2007

AbstractEvidence suggests that males and females differ with respect to the perception and experience of pain. Much of this work focuses on biological factors, yet it is also acknowledged that psychosocial issues are important. Within humans, socially and culturally constructed meanings of being and acting as a man or a woman should help us understand sex‐related differences in pain. However, such an approach has not been widely adopted, partly because of problems conveying sex and gender concepts. We argue here for an assimilation of gender studies concepts into pain research as a means of developing our understanding of the psychosocial influences on pain in men and women. In order to bridge the gap between gender studies and pain, we draw on theoretical developments in such gender concepts, and illustrate their application to pain. We make use of Doise's [Doise W. Levels of explanation in social psychology [Mapstone E, Trans.]. Cambridge (UK): Cambridge University Press. 1986 [original work published 1982]] meta‐theoretical model of levels of explanation in social psychology to show how gender may be conceptualized at an intra‐individual, situational, positional and ideological level of analysis. We then selectively review existing gender and pain research using these different levels of explanation. In doing so we also highlight that by considering the gender conceptualizations underpinning such studies we are able to point to directions for future research. We conclude by arguing that this approach opens up a new avenue for pain researchers, which we hope will further our understanding of this interesting phenomena.
SIMILARITIES IN THE SURNAMES OF ISLAND AND CONTINENTAL POPULATIONS OF THE NORTH-WESTERN MEDITERRANEAN AREA
Authors: LUCCHETTI E. , TASSO M. , PIZZETTI P. , DE IASIO S. , CARAVELLO G. U. 
Published: October 2007

SummaryThis paper compares the structures of the surnames of 75 municipal populations living in six north-western Mediterranean regions. Its purpose is to unravel the relations between the local populations in Corsica and Sardinia and the links between these populations and those living in the Italian and French continental territory. On the basis of the matrix of similarity of surnames, some topological representations have been drafted showing the above-mentioned relations between populations under the light of their geographical position, their recent history and studies of genetic analysis. Corsica has an eterogeneous surname structure and evident similarity of the north with Tuscany and some centres of continental France. When only the populations of Sardinia were taken into consideration, it emerged that they differ among each other in relation to their geographical position and their history; when, instead, they were considered in relation to other populations outside the island, it was possible to observe that they form a highly different cluster. This study also identified many differences in the analysed geographical areas of Sardinia. In the minor islands – Elba, Giglio, Capraia – the structure of the surnames has a Tuscan origin as well as some similarity with other geographically distant areas, as in the case of the island of Giglio, if compared with some communities of Liguria.
Hepatic fibrosis and Fasciola hepatica infection in cattle
Authors: A. Marcos Luis , Yi Pedro , Machicado Alfredo , Andrade Roy , Samalvides Frine , Sánchez Juvenal , Terashima Angélica 
Published: October 2007

AbstractThis study focuses on the development of fibrosis of the liver of cattle with Fasciola hepatica infection, correlating with the intensity of infection. Animals with an established diagnosis of chronic F. hepatica infection were identified in a slaughterhouse in Lima, Perú. The study included 24 fresh cattle livers from infected animals and two uninfected controls. Tissues were stored at 4°C for approximately 8 h after which they were brought to a necropsy room and examined. Between 9 and 12 biopsies were randomly obtained from each liver. Histological staining of formalin-fixed liver sections with haematoxylin and eosin (H & E) and Masson's trichrome were performed. Liver samples were examined using a pathology protocol that included 30 items. Histopathologically, 16 out of 30 liver specimens (67.6%) showed diffuse fibrotic lesions (cirrhosis) with a mean number of Fasciola of 116 ± 30 (range 4–435). Pathological data were matched to number of adult parasites and presence of cirrhosis after being reviewed by two independent pathologists. There was concordance between the two pathologists (K = 0.72). The group with cirrhosis showed an average of 116 ± 30 adult parasites whereas the group not showing cirrhosis contained 56 ± 28 flukes (P = 0.2). To measure how number of flukes and diagnosis of cirrhosis are related we used Kendall's tau-b coefficient; the correlation was +0.296 (P = 0.04). Receiver Operating Characteristic (ROC) curve results showed that the best point was 38 parasite adults, which had 93.8% sensitivity and 75% specificity. We conclude that as the number of F. hepatica adult forms increases, the likelihood of developing liver fibrosis will also increase in cattle.
Getting and maintaining attention in talk to young children
Authors: ESTIGARRIBIA BRUNO , CLARK EVE V. 
Published: October 2007

ABSTRACTWhen two people talk about an object, they depend on joint attention, a prerequisite for setting up common ground in a conversational exchange. In this study, we analyze this process for parent and child, with data from 40 dyads, to show how adults initiate joint attention in talking to young children (mean ages 1 ; 6 and 3 ; 0). Adults first get their children's attention with a summons (e.g.Ready?,See this?), but cease using such forms once children give evidence of attending. Children signal their attention by looking at the target object, evidence used by the adults. Only at that point do adults begin to talk about the object. From then on, they use language and gesture to offer information about and maintain attention on the target. The techniques adults rely on are interactive: they establish joint attention and maintain it throughout the exchange.