bluuebunny/crossref_metadata_2025_split huggingface dataset:
A weekly diary study on the buffering role of social support in the relationship between job insecurity and employee performance
Authors: Schreurs Bert H. J. , Hetty van Emmerik IJ. , Günter Hannes , Germeys Filip 
Published: March 2012

AbstractIn this article, the authors used a within‐person design to examine the relationship between job insecurity and employee in‐role and extra‐role performance, and the buffering role of time‐varying work‐based support (i.e., supervisor and colleague support) in this relationship. Weekly diary data gathered over the course of three weeks from 56 employees confronted with organizational restructuring and analyzed with a hierarchical linear modeling approach showed that weekly fluctuations in job insecurity negatively predicted week‐level in‐role performance. As predicted, supervisor support moderated the intra‐individual relationship between job insecurity and in‐role performance, so that employees' in‐role performance suffered less from feeling job insecurity during weeks in which they received more support from their supervisor. No relationship between job insecurity and extra‐role performance was observed. This within‐person study contributes to research on job insecurity that has primarily focused on inter‐individual differences in job insecurity and their associations with job performance. Theoretical and practical implications for human resource management are discussed. © 2012 Wiley Periodicals, Inc.
Non‐linear microscopy of smooth muscle cells in artificial extracellular matrices made of cellulose
Authors: Brackmann Christian , Dahlberg Jan‐Olof , Vrana Nihal Engin , Lally Caitriona , Gatenholm Paul , Enejder Annika 
Published: March 2012

AbstractNon‐linear microscopy has been used to characterize bovine smooth muscle cells and their proliferation, migration, and differentiation in hydrogel cellulose scaffolds, toward the development of fully functional blood vessel implants. The extracellular matrix (ECM) composed of cellulose and endogenous collagen fibers was imaged using Second Harmonic Generation (SHG) microscopy and the cell morphology by Coherent Anti‐Stokes Raman Scattering (CARS) microscopy. Images prove that cells adhere on the cellulose scaffold without additional surface modification and that both contractile and proliferating phenotypes are developed. This work shows that non‐linear microscopy contributes with unique insights in cell interactions with (artificial) ECM components and has the potential to become an established characterization method in tissue engineering. (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Segmentation and fusion on the midline: Basibranchial homologies in cypriniform fishes
Authors: Engeman Jeffrey M. , Mabee Paula M. 
Published: March 2012

AbstractThe development and homologies of the median elements of the ventral hyoid and branchial arches of Cypriniformes have been unclear. We compared the developmental morphology of this region across five species (Cycleptus elongatus, Luxilus zonatus, Danio rerio, Devario auropurpureus, and Cobitis striata), representing three of five major clades of cypriniforms. The development of basibranchial 1 is similar in catostomids and cyprinids, where a single, elongate, basihyal + anterior copula divides into separate elements. A gap develops between the posterior end of the basihyal cartilage and the anterior copula in catostomids but in cyprinids (Luxiluszonatus, Danio rerio, and Devarioauropurpureus) there is little separation and the basihyal and basibranchial 1 may grow close together or retain a cartilaginous connection (Danio rerio, several outgroups). In loaches and Gyrinocheilus, the gap posterior to the basihyal has been alternately interpreted as either the absence or posterior displacement of basibranchial 1. Uniquely among examined species, in Cobitis striata, the basihyal cartilage and anterior copula form as separate cartilages and remain distinct throughout development with a prominent gap between the basihyal and most anterior basibranchial, which we interpret as loss of basibranchial 1. In the posterior region associated with branchial arches 4 and 5, all examined species except Danio rerio, which has only a basibranchial 4 cartilage, have separate basibranchial 4 and 5 cartilages in early ontogeny. Basibranchials 4 and 5 remain separate in Cycleptus elongatus, Devario auropurpurea, and Cobitis striata, but fuse in Luxilus zonatus to form a posterior copula. The orientation of basibranchial 4 and 5 cartilages in Cobitis striata is similar to catostomids and cyprinids. The most posterior median element in the branchial arches, the post‐ceratobranchial cartilage, generally forms as a separate cartilage in catostomids but in Cobitis striata is connected with basibranchial 5 cartilage from earliest appearance. J. Morphol., 2012. © 2012 Wiley Periodicals, Inc.
Ontogenetic influence on neural spine bifurcation in diplodocoidea (dinosauria: Sauropoda): A critical phylogenetic character
Authors: Woodruff D. Cary , Fowler Denver W. 
Published: March 2012

AbstractWithin Diplodocoidea (Dinosauria: Sauropoda), phylogenetic position of the three subclades Rebbachisauridae, Dicraeosauridae, and Diplodocidae is strongly influenced by a relatively small number of characters. Neural spine bifurcation, especially within the cervical vertebrae, is considered to be a derived character, with taxa that lack this feature regarded as relatively basal. Our analysis of dorsal and cervical vertebrae from small‐sized diplodocoids (representing at least 18 individuals) reveals that neural spine bifurcation is less well developed or absent in smaller specimens. New preparation of the roughly 200‐cm long diplodocid juvenile Sauriermuseum Aathal 0009 reveals simple nonbifurcated cervical neural spines, strongly reminiscent of more basal sauropods such as Omeisaurus. An identical pattern of ontogenetically linked bifurcation has also been observed in several specimens of the basal macronarian Camarasaurus, suggesting that this is characteristic of several clades of Sauropoda. We suggest that neural spine bifurcation performs a biomechanical function related to horizontal positioning of the neck that may become significant only at the onset of a larger body size, hence, its apparent absence or weaker development in smaller specimens. These results have significant implications for the taxonomy and phylogenetic position of taxa described from specimens of small body size. On the basis of shallow bifurcation of its cervical and dorsal neural spines, the small diplodocid Suuwassea is more parsimoniously interpreted as an immature specimen of an already recognized diplodocid taxon. Our findings emphasize the view that nonmature dinosaurs often exhibit morphologies more similar to their ancestral state and may therefore occupy a more basal position in phylogenetic analyses than would mature specimens of the same species. In light of this, we stress the need for phylogenetic reanalysis of sauropod clades where vital characters may be ontogenetically variable, particularly when data is derived from small individuals. J. Morphol., 2012. © 2012 Wiley Periodicals, Inc.
A note on optimal allocations for the second elementary symmetric function with applications for optimal reliability design
Authors: Peng Chien‐Yu 
Published: March 2012

AbstractThis article considers the problem of determining the optimal size allocation and optimal number of experimental conditions for a second elementary symmetric function with different coefficients. Analytical solutions for several practical applications are derived and the general formulation is used to elucidate the foundation between different parametric models found in recent studies. A geometrical interpretation of the structure of some theoretical results is also provided. This approach renders some complex problems more tractable than what numerical search algorithms would allow. © 2012 Wiley Periodicals, Inc. Naval Research Logistics, 2012
Nonlinear observers for a class of nonlinear descriptor systems
Authors: Yang Chunyu , Zhang Qingling , Chai Tianyou 
Published: March 2012

SUMMARYThis paper considers a class of nonlinear descriptor systems whose nonlinear terms are time‐varying and satisfy a quadratic inequality. An nonlinear observer is constructed and the error system is represented by a Lur'e descriptor system (LDS). Motivated by the basic idea of absolute stability theory, both types of full‐order and reduced‐order observers are constructed by a unified approach. The proposed method generalizes the existing ones for standard state‐space systems, and global convergence of the nonlinear observer is achieved without the usual global Lipschitz restriction. Furthermore, the stability criterion for the error system extends the existing ones for LDS in the sense that the involved interconnected nonlinearities are time‐varying and in unbounded sector. Finally, the design methods are reduced to a linear matrix inequality problem and illustrated by two numerical examples. Copyright © 2012 John Wiley & Sons, Ltd.
The preparation and characterization of carboxylic acid‐coated silica nanoparticles
Authors: Cash Brandon M. , Wang Lei , Benicewicz Brian C. 
Published: March 2012

AbstractThe preparation of carboxylic acid‐coated silica nanoparticles was investigated. A monolayer of carboxylic acid residues with controllable graft density was anchored to the nanoparticle by a ring‐opening reaction with succinic anhydride. Poly(methacrylic acid) [poly(MAA)] grafted nanoparticles were prepared via a polymerization–deprotection strategy. Tert‐butyl methacrylate was polymerized from the surface of silica nanoparticles in a predictable manner and with excellent control over the molecular weight distribution. Subsequent removal of the tert‐butyl group resulted in poly (MAA) grafted nanoparticles. The polymer nanoparticles were also functionalized with dyes, which may be useful in tracking the particles in biological systems. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012
Internal Structure of a Lithalsa in the Akkol Valley, Russian Altai Mountains
Authors: Iwahana Go , Fukui Kotaro , Mikhailov Nikolai , Ostanin Oleg , Fujii Yoshiyuki 
Published: March 2012

ABSTRACTPerennial frost mounds are present near the edges of ponds located on the terrace between the mountain flank and a valley‐bottom lake in the Akkol valley of the Russian Altai Mountains. These mounds are 10–50 m in diameter and 3–6 m in height. We describe one mound, identified as a lithalsa, which had been eroded so as to expose almost its entire vertical cross‐section, revealing its internal structure. The frozen core consisted mainly of soil segments suspended in reticulate ice lenses with a mean thickness of 11–48 mm and a maximum thickness of about 160 mm. The shapes of the soil segments matched their neighbours. Other features included soil segments suspended in the ice veins shaped like ‘En echelon gash veins’, and the presence of a radial structure of ice‐rich and sediment‐rich frozen bands. These features all suggest the greater importance of a differential stress field during heaving of the mound and after ice segregation, compared to the thermal gradient and water supply. Copyright © 2012 John Wiley & Sons, Ltd.
Geographic variability in response to azinphos‐methyl in field‐collected populations of Cydia pomonella (Lepidoptera: Tortricidae) from Argentina
Authors: Soleño Jimena , Anguiano Olga L , Cichón Liliana B , Garrido Silvina A , Montagna Cristina M 
Published: March 2012

AbstractBACKGROUND: Resistance to insecticides has been related to application history, genetic factors of the pest and the dynamic within the treated area. The aim of this study was to assess the geographic variation in azinphos‐methyl response and the role of esterase and cytochrome P450 monooxygenase enzymes in codling moth populations collected within different areas of the Río Negro and Neuquén Valley, Argentina.RESULTS: Diapausing field‐collected populations showed resistance ratios at the LC50 that were 0.7–8.7 times higher than that of the susceptible strain. Mean esterase (EST) and cytochrome P450 monooxygenase activities (expressed as α‐N min−1 mg−1 prot−1 and pg 7‐OHC insect−1 min−1 respectively) were significantly correlated with LD50 values from the field‐collected populations. In addition, azinphos‐methyl response was associated with the geographic area where the insect population was collected: populations from isolated and more recent productive areas presented significantly lower resistance ratios in comparison with populations from older and more intensive productive areas.CONCLUSION: The populations assayed presented different resistance levels to azinphos‐methyl. The response was highly correlated with the orchard's geographic location. EST and ECOD activities were involved in azinphos‐methyl response in the given region. Copyright © 2012 Society of Chemical Industry
EDESR of impurity centers in nanostructures inserted in silicon microcavities
Authors: Bagraev Nikolay , Danilovsky Eduard , Gehlhoff Wolfgang , Gets Dmitry , Klyachkin Leonid , Kudryavtsev Andrey , Kuzmin Roman , Malyarenko Anna , Mashkov Vladimir , Romanov Vladimir 
Published: March 2012

AbstractWe present the first findings of the new electrically detected electron spin resonance technique (EDESR) which reveal single point defects in the ultra‐narrow silicon quantum wells (Si‐QW) confined by the superconductor δ‐barriers. This technique allows the ESR identification without the application of the external cavity as well as the high frequency (hf) source and recorder, with measuring the only magnetoresistance caused by the hf emission from the δ‐barriers in the presence of the microcavity embedded in the Si‐QW plane. The new resonant positive magnetoresistance data are interpreted here in terms of the interference transition in the diffusive transport of free holes respectively between the weak antilocalization regime in the range of magnetic fields far from the ESR of a paramagnetic point defect located inside or near the conductive channel and the weak localization regime in the range of magnetic fields corresponding to the ESR of that defect. (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Second‐harmonic generation microscopy of ferroelectric organic conductor using hydrostatic pressure apparatus with Ar as a heat sink
Authors: Yamamoto Kaoru , Kowalska Aneta Aniela , Yakushi Kyuya 
Published: March 2012

AbstractLow temperature measurements of optical second‐harmonic generation (SHG) were performed for organic conductors showing ferroelectric charge ordering. To avoid the heating due to focused laser beam without applying mechanical stress to the samples, the organic crystals were mounted in liquid argon heat‐transfer medium. The noble gas was sealed in a diamond‐anvil cell type pressure cell, though the pressure was regulated around ambient level. The technique of the low temperature nonlinear optical microscopy is presented. (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
First principles calculations of pKa values of amines in aqueous solution: Application to neurotransmitters
Authors: Rebollar‐Zepeda Aida Mariana , Galano Annia 
Published: March 2012

AbstractA systematic search for computational strategies able to accurately predict pKa values of protonated amines (HA+) has been performed. Thermodynamic cycles have been used in conjunction with the cluster‐continuum model, including up to eight explicit water molecules per system. The calculations have been performed with nine different methods within the density functional theory (DFT), and with MP2. It was found that including one explicit water molecule in the vicinity of the protonated site is highly important for obtaining accurate results. We recommend the F2 reaction scheme [HA+(H2O) + 3H2O = A + H3O+(3H2O)], combined with M05‐2X/6‐311++G(d,p) calculations. This particular combination produces mean unsigned errors (MUE) equal to 0.54 for all the tested amines, and 0.51 pKa units for the studied neurotransmitters. Moreover it was found to be the only one that systematically leads to errors lower than, or very close to, 1 unit of pKa for every one of the studied species, with the maximum error equal to 1.09 pKa units. This scheme has the additional advantages of being computationally feasible for amines of relative large size, independent of experimental values, and free of fitting‐based corrections. In addition the high influence of the reference acid of choice, in the proton exchange scheme (D), on the quality of the pKa values of amines is discussed. © 2012 Wiley Periodicals, Inc.
Large‐scale DFT calculations in implicit solvent—A case study on the T4 lysozyme L99A/M102Q protein
Authors: Dziedzic Jacek , Fox Stephen J. , Fox Thomas , Tautermann Christofer S. , Skylaris Chris‐Kriton 
Published: March 2012

AbstractRecently, variants of implicit solvation models for first principles electronic structure calculations based on a direct solution of the nonhomogeneous Poisson equation in real space have been developed. These implicit solvation models are very elegant from a physical point of view as the solute cavity is defined directly via isosurfaces of the electronic density, and the molecular charge is polarized self‐consistently by the reaction field of the dielectric continuum which surrounds the solute. Nevertheless, the implementation of these models is technically complex and requires great care. A certain level of care is required from users of such models as a number of numerical parameters need to be given appropriate values to obtain the most accurate and physically relevant results. Here, we describe in what parts of the solvent model each of these numerical parameters is involved and present a detailed study of how they can affect the calculation, using the solvation model which has been implemented in the ONETEP program for linear‐scaling density functional theory (DFT) calculations. As ONETEP is capable of DFT calculations with thousands of atoms, we focus our investigation of the numerical parameters with a case study on protein–ligand complexes of the entire 2602‐atom T4 Lysozyme L99/M102Q protein. We examine effects on solvation energies and binding energies, which are critical quantities for computational drug optimization and other types of biomolecular simulations. We propose optimal choices of these parameters suitable for routine “production” calculations. © 2012 Wiley Periodicals, Inc.
Size‐Dependent Fracture Mode Transition in Copper Nanowires
Authors: Peng Cheng , Zhan Yongjie , Lou Jun 
Published: March 2012

AbstractIn situ uni‐axial tensile tests of single‐crystalline copper nanowires are performed using a micromechanical device inside a scanning electron microscope chamber. The single‐crystalline copper nanowires are synthesized by solvothermal processes, and the growth direction along the wire axis is the <110> orientation as confirmed by transmission electron microscopy (TEM) selected area diffraction (SAD) analysis. The fracture strengths of copper nanowires are found to be much higher than that of bulk copper. More interestingly, both ductile and brittle‐like fracture modes are found in the same batch of fabricated nanowires, and the fracture modes appear to be dependent on the diameters of tested nanowires. From the analysis of fracture surfaces, sample morphologies and corresponding stress–strain curves, the competition between deformation and fracture mechanisms controlled by initial defects density and by the probability of dislocation interactions is attributed to this intriguing size‐dependent fracture mode transition.
Compensation for cranial spill‐in into the cerebellum improves quantitation of striatal dopamine D2/3 receptors in rats with prolonged [18F]‐DMFP infusions
Authors: Mille Erik , Cumming Paul , Rominger Axel , La Fougère Christian , Tatsch Klaus , Wängler Björn , Bartenstein Peter , Böning Guido 
Published: March 2012

AbstractThe condition of steady‐state receptor binding in positron emission tomography (PET) studies is best obtained through the use of a bolus plus steady‐infusion paradigm. This is a particularly important consideration in the context of in vivo competition studies, where a pharmacological challenge can be administered during the interval of steady‐state ligand binding, as in the case of [11C]‐raclopride studies with amphetamine challenge. However, the short half‐life of 11C imposes limits on the practical duration of constant infusions. Therefore, we chose to test [18F]‐DMFP as a tracer for dopamine D2/3 receptors in rat striatum in the paradigm. Using a conventional bolus injection, the [18F]‐DMFP BPND was 3.8 in striatum of anesthetized rats. When followed by a constant infusion, we obtained quasi‐stable BPND estimates of 4.5 within an interval of 45 min. During infusions lasting up to 4 h, BPND declined progressively. This seemed due to the progressive spill‐in of radioactivity from the cranium to the cerebellum reference region, despite optimized iterative reconstruction of the images. Therefore, we propose a new concept of compensation for this spill‐in effect using pharmacokinetic considerations, without requiring high‐resolution anatomical images. Challenge with amphetamine (1 and 4 mg/kg) evoked an ∼25% reduction in BPND. There was no clear evidence of dose‐dependence in the striatal‐binding changes, despite the considerably greater physiological effect, as documented by ECG. Thus, the general applicability of the bolus plus infusion method with [18F]‐DMFP for small animal studies is impeded by the substantial labeling of the cranium. The cranial uptake was linear, indicating first‐order kinetics for the enzymatic defluorination of the tracer. Based on this phenomenon, we developed an analytic method compensating for the effects of progressive cranial labeling on the estimation of specific binding in striatum. Synapse, 2012. © 2012 Wiley Periodicals, Inc.
Sonographic predictors of surgery in fetal coarctation of the aorta
Authors: Jowett V. , Aparicio P. , Santhakumaran S. , Seale A. , Jicinska H. , Gardiner H. M. 
Published: March 2012

AbstractObjectivesIsolated fetal coarctation of the aorta (CoA) has high false‐positive diagnostic rates by cardiologists in tertiary centers. Isthmal diameter Z‐scores (I), ratio of isthmus to duct diameters (I:D), and visualization of CoA shelf (Shelf) and isthmal flow disturbance (Flow) distinguish hypoplastic from normal aortic arches in retrospective studies, but their ability to predict a need for perinatal surgery is unknown. The aim of this study was to determine whether these four sonographic features could differentiate prenatally cases which would require neonatal surgery in a prospective cohort diagnosed with CoA by a cardiologist.MethodsFrom 83 referrals with cardiac disproportion (January 2006 to August 2010), we identified 37 consecutive fetuses diagnosed with CoA. Measurements of I and I:D were made and the presence of Shelf or Flow recorded. Sensitivity, specificity and areas under receiver–operating characteristics curves, using previously reported limits of I < − 2 and I:D < 0.74, as well as Shelf and Flow were compared at first and final scan. Associations between surgery and predictors were compared using multivariable logistic regression and changes in measurements using ANCOVA.ResultsAmong the 37 fetuses, 30 (81.1%) required surgery and two with an initial diagnosis of CoA were revised to normal following isthmal growth, giving an 86% diagnostic accuracy at term. The median age at first scan was 22.4 (range. 16.6–7.0) weeks and the median number of scans per fetus was three (range, one to five). I < − 2 at final scan was the most powerful predictor (odds ratio, 3.6 (95% CI, 0.47–27.3)). Shelf was identified in 66% and Flow in 50% of fetuses with CoA.ConclusionIncorporation of these four sonographic parameters in the assessment of fetuses with suspected CoA at a tertiary center resulted in better diagnostic precision regarding which cases would require neonatal surgery than has been reported previously. Copyright © 2012 ISUOG. Published by John Wiley & Sons, Ltd.