bluuebunny/crossref_metadata_2025_split huggingface dataset:
Using cloud computing to manage costs
Authors: Lee Lorraine S. , Mautz Jr. R. David 
Published: February 2012

AbstractThe growing availability of cloud computing provides opportunities to manage costs—by effectively outsourcing selected information technology (IT) functions. But like all other outsourcing decisions, you must conduct a careful analysis—to ensure that potential savings outweigh both costs and the risks of ceding control to an outside vendor. This article provides guidance for managers considering cloud computing as a cost management strategy. © 2012 Wiley Periodicals, Inc.
VIOLENCE AND ECONOMIC DEVELOPMENT IN COLOMBIAN CITIES: A DYNAMIC PANEL DATA ANALYSIS
Authors: Cotte Poveda Alexander 
Published: February 2012

ABSTRACTThis paper studies the socio‐economic determinants of violence in the seven most important cities in Colombia. Derived from theories rooted in classic works, including Becker's paradigm, criminal inertia, social disorganisation, urbanism and strain, we formulate several hypotheses on the socio‐economic determinants of violence. To test these hypotheses, a dynamic panel data analysis is employed. The analysis shows that cities’ deprivation and high population density are strong predictors of homicide rates. Comparing the results among Colombian cities, we find support indicating that city‐level homicide rates are influenced by the city's level of development. Moreover, we find evidence that economic growth, inequality, poverty and human capital influence violence in the cities studied, which could generate negative effects on the economic and social development of Colombia. Copyright © 2012 John Wiley & Sons, Ltd.
Characterization of a neutral pectin lyase produced by Oidiodendron echinulatum MTCC 1356 in solid state fermentation
Authors: Yadav Sangeeta , Dubey Amit Kumar , Anand Gautam , Yadav Dinesh 
Published: February 2012

AbstractA neutral pectin lyase produced by a new fungal strain Oidiodendron echinulatum MTCC 1356 under solid state fermentation using wheat bran as agro waste has been studied. The enzyme was purified by ammonium sulphate precipitation (30–60%), DEAE anion exchange and Sephadex G‐100 column chromatographies. The SDS‐PAGE and native PAGE revealed two bands of sizes 42 and 47 kDa. The enzyme was purified 37 fold with specific activity of 4.5 U/mg and 2.25% yield. The Km and Vmax values determined using citrus pectin were 1.2 mg/ml and 0.36 IU/min respectively. The pH and temperature optima were pH 7.0 and 50 °C, respectively. The pH stability was around 5.0 for 24 h at 20 °C. The purified enzyme retained maximum activity for 30 min upto 50 °C. The activation energy for thermal denaturation of the purified enzyme was found to be 60.0 kJ/Mol. The effects of various metal ions and protein inhibitors on enzyme activity have revealed total inhibition of the enzyme activity in the presence of Ag+and Cu+and KMnO4 at 1 mM. The neutral pectin lyase showed retting of Crotalaria juncea fibre in the presence of EDTA. (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Concomitant evolution of wear and squeaking in dual‐severity, lubricated wear testing of ceramic‐on‐ceramic hip prostheses
Authors: Sanders Anthony , Tibbitts Ira , Brannon Rebecca 
Published: February 2012

AbstractCeramic‐on‐ceramic (CoC) hip bearings were tested in short‐term wear tests with a systematically varied contact force. Continuous vibration and intermittent surface roughness measurements were obtained to elucidate potential causes of in vivo hip joint squeaking. The three‐phase test comprised alternating cycles of edge loading (EL) and concentric articulation (CA), always using ample serum lubricant. A 50,000‐cycle wear trial in which the contact force during CA was distant from the head's wear patch yielded no squeaking and practically no liner roughening. In 10‐cycle trials of an edge‐worn head coupled with a pristine liner, the contact force was varied in magnitude and point of application; immediate, recurrent squeaking occurred only when the contact force exceeded a critical threshold value and was centered upon the head's wear patch. In a 27,000‐cycle wear trial with the contact force applied near the margin of the head's wear patch, recurrent squeaking emerged progressively as the liner's inner surface was roughened via its articulation with the worn portion of the head. The results reveal key conditions that yield recurrent squeaking in vitro in various scenarios without resorting to implausible dry conditions. A fundamental theory explains that hip squeaking is induced by myriad stress waves emanating from asperity collisions; yet, the root cause is edge loading. © 2012 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 30:1377–1383, 2012
Early adult sexual assault and disordered eating: The mediating role of posttraumatic stress symptoms
Authors: Dubosc Auberi , Capitaine Maud , Franko Debra L. , Bui Eric , Brunet Alain , Chabrol Henri , F. Rodgers Rachel 
Published: February 2012

AbstractAlthough adult sexual assault has been suggested to be a risk factor for disordered eating, little is known about the pathways leading to this disorder. This study aimed to examine the mediating effect of depressive symptoms and symptoms of posttraumatic stress disorder (PTSD), in the relationship between sexual assault and disordered eating among female students. A sample of 296 French female students completed a questionnaire assessing experiences of sexual assault from age 15, PTSD symptoms, depressive symptoms, and disordered eating. Results revealed that PTSD symptoms fully mediated the effect of early adult sexual assault on disordered eating (B = 1.10, SE = 1.64), and depressive symptoms were a partial mediator of this relationship (B = 2.64, SE = 1.28). When examining both mediators simultaneously the relationship was fully mediated and neither variable emerged as a significantly stronger mediator. Our findings highlight the complex relationship between PTSD symptoms, depressive symptoms, and disordered eating following sexual assault. Further investigation into the temporal relationships between these variables would contribute to inform prevention interventions for disordered eating.
The mediating role of trauma‐related symptoms in the relationship between sexual victimization and physical health symptomatology in undergraduate women
Authors: Tansill Erin C. , Edwards Katie M. , Kearns Megan C. , Gidycz Christine A. , Calhoun Karen S. 
Published: February 2012

AbstractPrevious research suggests that posttraumatic stress symptomatology is a partial mediator of the relationship between sexual assault history in adolescence/adulthood and physical health symptomatology (e.g., Eadie, Runtz, & Spencer‐Rodgers, 2008). The current study assessed a broader, more inclusive potential mediator, trauma‐related symptoms in the relationship between sexual victimization history (including both childhood and adolescent/adulthood sexual victimizations) and physical health symptomatology in a college sample. Participants were 970 young women (M = 18.69, SD = 1.01), who identified mostly as Caucasian (86.7%), from 2 universities who completed a survey packet. Path analysis results provide evidence for trauma‐related symptoms as a mediator in the relationship between adolescent/adulthood sexual assault and physical health symptomatology, χ2 (1, N = 970) = 1.55, p = .21; comparative fit index = 1.00; Tucker‐Lewis index = 0.99; root mean square error of approximation = .02, 90% confidence interval [.00, .09], Bollen‐Stine bootstrap statistic, p = .29. Childhood sexual abuse was not related to physical health symptomatology, but did predict trauma‐related symptoms. Implications of these findings suggest that college health services would benefit from targeted integration of psychiatric and medical services for sexual assault survivors given the overlap of psychological and physical symptoms.
The C‐tail anchored TssL subunit, an essential protein of the enteroaggregative Escherichia coli Sci‐1 Type VI secretion system, is inserted by YidC
Authors: Aschtgen Marie‐Stéphanie , Zoued Abdelrahim , Lloubès Roland , Journet Laure , Cascales Eric 
Published: February 2012

AbstractType VI secretion systems (T6SS) are macromolecular complexes present in Gram‐negative bacteria. T6SS are structurally similar to the bacteriophage cell‐puncturing device and have been shown to mediate bacteria–host or bacteria–bacteria interactions. T6SS assemble from 13 to 20 proteins. In enteroaggregative Escherichia coli (EAEC), one of the subassemblies is composed of four proteins that form a trans‐envelope complex: the TssJ outer membrane lipoprotein, the peptidoglycan‐anchored inner membrane TagL protein, and two putative inner membrane proteins, TssL and TssM. In this study, we characterized the TssL protein of the EAEC Sci‐1 T6SS in terms of localization, topology, and function. TssL is a critical component of the T6SS, anchored to the inner membrane through a single transmembrane segment located at the extreme C‐terminus of the protein. We further show that this transmembrane segment is essential for the function of the protein and its proper insertion in the inner membrane is dependent upon YidC and modulated by the Hsp70 homologue DnaK.
Mathematical analysis of a model of chemotaxis arising from morphogenesis
Authors: Stinner Christian , Tello J. Ignacio , Winkler Michael 
Published: February 2012

We consider non‐negative solution couples (u,v) of
urn:x-wiley:01704214:media:mma1573:mma1573-math-0001 with positive parameters χ and λ, where the spatial domain is the interval (0,1). This system appears as a limit case of a model for morphogenesis proposed by Bollenbach et al. (Phys. Rev. E. 75, 2007). Under suitable boundary conditions, modeling the presence of a morphogen source at x = 0, we prove the existence of a global and bounded weak solution using an approximation by problems where diffusion is introduced in the ordinary differential equation. Moreover, we prove the convergence of the solution to the unique steady state provided that χ is small and λ is large enough.Numerical simulations both illustrate these results and give rise to further conjectures on the solution behavior that go beyond the rigorously proved statements. Copyright © 2012 John Wiley & Sons, Ltd.
Mechanical property tuning of semicrystalline network polymers by controlling rates of crystallization and crosslinking
Authors: Oya Nobuhiro , Saitoh Shunsuke , Furuhashi Yukiko , Yoshie Naoko 
Published: February 2012

AbstractSemicrystalline network polymers were obtained by the Diels–Alder (DA) reaction of furyl‐telechelic poly(ε‐caprolactone) and tris(2‐maleimide ethyl)amine. Controlling the rates of crystallization and crosslinking reaction gave materials with various properties. Curing at a temperature much below Tm of poly(ε‐caprolactone), at which crystallization proceeded first followed by DA reaction, gave a hard and stiff material, whereas curing above Tm gave a soft and stretchable one. When crystallization and crosslinking were promoted simultaneously, tough and ductile materials were obtained. Structural analysis of the network polymers showed that the variation in the properties was derived from the difference in the crystallinity, crystallite size, and network structure. Therefore, materials with various mechanical properties, from soft to hard, could be obtained by simple thermal treatment. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012
Novel thermo‐responsive self‐assembly micelles from a double brush‐shaped PNIPAM‐g‐(PA‐b‐PEG‐b‐PA)‐g‐PNIPAM block copolymer with PNIPAM polymers as side chains
Authors: Luo Yan‐Ling , Yu Wei , Xu Feng , Zhang Li‐Li 
Published: February 2012

AbstractA novel double brush‐shaped copolymer with amphiphilic polyacrylate‐b‐poly(ethylene glycol)‐b‐poly acrylate copolymer (PA‐b‐PEG‐b‐PA) as a backbone and thermosensitive poly(N‐isopropylacrylamide) (PNIPAM) long side chains at both ends of the PEG was synthesized via an atom transfer radical polymerization (ATRP) route, and the structure was confirmed by FTIR, 1H NMR, and SEC. The thermosensitive self‐assembly behavior was examined via UV‐vis, TEM, DLS, and surface tension measurements, etc. The self‐assembled micelles, with low critical solution temperatures (LCST) of 34–38 °C, form irregular fusiform and/or spherical morphologies with single, double, and petaling cores in aqueous solution at room temperature, while above the LCST the micelles took on more regular and smooth spherical shapes with diameter ranges from 45 to 100 nm. The micelle exhibits high stabilities even in simulated physiological media, with low critical micellization concentration (CMC) up to 5.50, 4.89, and 5.05 mg L−1 in aqueous solution, pH 1.4 and 7.4 PBS solutions, respectively. The TEM and DLS determination reveled that the copolymer micelle had broad size distribution below its LCST while it produces narrow and homogeneous size above the LCST. The cytotoxicity was investigated by MTT assays to elucidate the application potential of the as‐prepared block polymer brushes as drug controlled release vehicles. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012
Copolymerization of ethylene with acrylonitrile promoted by novel nonmetallocene catalysts with phenoxy‐imine ligands
Authors: Zhang Xinli , Liu Zhi , Yi Jianjun , Li Fengjiao , Huang Haibing , Liu Wei , Zhen Hongpeng , Huang Qigu , Gao Kejing , Yang Wantai 
Published: February 2012

AbstractA series of novel nonmetallocene catalysts with phenoxy‐imine ligands was synthesized by the treatment of phthaldialdehyde, substituted phenol with TiCl4, ZrCl4, and YCl3 in THF. The structures and properties of the catalysts were characterized by 1H NMR and elemental analysis. These catalysts were used for copolymerization of ethylene with acrylonitrile after activated by methylaluminoxane (MAO). The effects of copolymerization temperature, Al/M (M = Ti, Zr, and Y) ratio in mole, concentrations of catalyst and comonomer on the polymerization behaviors were investigated in detail. These results revealed that these catalysts were favorable for copolymerization of ethylene with acrylonitrile. Cat.3 was the most favorable one for the copolymerization of ethylene with acrylonitrile, and the catalytic activity was up to 2.19 × 104 g PE/mol.Ti.h under the conditions: polymerization temperature of 50 °C, Al/Ti molar ratio of 300, catalyst concentration of 1.0 × 10–4 mol/L, and toluene as solvent. The resultant polymer was characterized by FTIR, cross‐polarization magic angle spinning, 13C NMR, WAXD, GPC, and DSC. The results confirmed that the obtained copolymer featured high‐weight–average molecular weight, narrow molecular weight distribution about 1.61–1.95, and high‐acrylonitrile incorporation up to 2.29 mol %. Melting temperature of the copolymer depended on the content of acrylonitrile incorporation within the copolymer chain. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012
Block and random copolymerization of ε‐caprolactone, L‐, and rac‐lactide using titanium complex derived from aminodiol ligand
Authors: Dakshinamoorthy Deivasagayam , Peruch Frédéric 
Published: February 2012

AbstractA series of di‐ and triblock copolymers [poly(L‐lactide‐b‐ε‐caprolactone), poly(D,L‐lactide‐b‐ε‐caprolactone), poly(ε‐caprolactone‐b‐L‐lactide), and poly(ε‐caprolactone‐b‐L‐lactide‐b‐ε‐caprolactone)] have been synthesized successfully by sequential ring‐opening polymerization of ε‐caprolactone (ε‐CL) and lactide (LA) either by initiating PCL block growth with living PLA chain end or vice versa using titanium complexes supported by aminodiol ligands as initiators. Poly(trimethylene carbonate‐b‐ε‐caprolactone) was also prepared. A series of random copolymers with different comonomer composition were also synthesized in solution and bulk of ε‐CL and D,L‐lactide. The chemical composition and microstructure of the copolymers suggest a random distribution with short average sequence length of both the LA and ε‐CL. Transesterification reactions played a key role in the redistribution of monomer sequence and the chain microstructures. Differential scanning calorimetry analysis of the copolymer also evidenced the random structure of the copolymer with a unique Tg. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012
Metal/organic barrier formation for a C60/Au interface: From the molecular to the monolayer limit
Authors: Abad Enrique , Ortega José , Flores Fernando 
Published: February 2012

AbstractThe C60/Au(111) metal/organic (MO) interface barrier formation is analyzed from the single molecule limit to the full monolayer case by means of density functional theory (DFT) calculations taking into account charging energy effects to properly describe the electronic structure of the interface and van der Waals (vdW) interactions to obtain the molecule‐surface adsorption distance. In our calculations we obtain the density of states (DOS) projected on the C60‐molecule, the energy position of its charge neutrality level (CNL), its highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) levels, as well as the interface Fermi level. From these calculations we also obtain the charge transfer, the induced potential on the molecule and the interface screening parameter, S. We find a significant evolution from the single molecule to the full monolayer, with the energy barrier for electrons decreasing with the molecule deposition: this reflects an increasing interface screening effect for larger molecule coverages. We also analyze the relationship between S and the molecule charging energy, U, and deduce an effective interaction between electrons in different C60 molecules.
Whispering gallery modes in deformed hexagonal resonators
Authors: Grundmann Marius , Dietrich Christof P. 
Published: February 2012

AbstractOptical resonances in polygonal resonators are due to whispering gallery modes (WGM). We investigate WGM in regular and deformed hexagonal ZnO microwire resonators. Four types of geometries are investigated: regular hexagonal and dodecagonal cross sections, hexagonal cross section elongated for one pair of facets and hexagonal cross section deformed by bending (uniaxial stress). Experimental data on mode energies and angular dispersion are correlated with model calculations and Poincaré surfaces of section. Hexagonal (ϕ = 60°), square (ϕ = 45°), triangular (ϕ = 30°), and Fabry–Pérot modes (ϕ = 0°) are observed in the various investigated geometries, ϕ being the angle of incidence at the facets with respect to the normal direction. magnified image
Hexagonal WGMs (green, 6‐WGM), triangular (red, 3‐WGM), and double‐triangular (blue, D3‐WGM) rays in regular hexagons, elongated hexagons and hexagons deformed by bending. Triangular WGMs are stable modes in all three resonators. Hexagonal modes are not stable in the bent hexagon.
Controlling quantum dot emission by integration of semiconductor nanomembranes onto piezoelectric actuators
Authors: Rastelli A. , Ding F. , Plumhof J. D. , Kumar S. , Trotta R. , Deneke Ch. , Malachias A. , Atkinson P. , Zallo E. , Zander T. , Herklotz A. , Singh R. , Křápek V. , Schröter J. R. , Kiravittaya S. , Benyoucef M. , Hafenbrak R. , Jöns K. D. , Thurmer D. J. , Grimm D. , Bester G. , Dörr K. , Michler P. , Schmidt O. G. 
Published: February 2012

AbstractThis paper reviews the recent advances obtained by integrating semiconductor epitaxial films with embedded self‐assembled quantum dots (QDs) on top of single‐crystal piezoelectric substrates made of lead magnesium niobate–lead titanate (PMN‐PT). This combination allows us to study in detail the effects produced by variable strains (up to about ± 0.2%) on the excitonic emission of single QDs and to add a powerful “tuning knob” to QDs. Biaxial stress can be used to reversibly shift the emission wavelength of QDs in a spectral range wider than 10 meV and to modify the relative binding energies of excitonic species. Anisotropic stress has instead a strong influence on the fine structure splitting of neutral excitons. Finally, we present experimental results on the effect of biaxial strain on the optical modes of microring optical resonators and show a simple approach enabling the compensation of piezo‐creep via a closed‐loop system.magnified image
Schematic illustration of a QD membrane integrated on top of a PMN‐PT substrate. Stress provided by the piezoelectric substrate allows broad range tuning of the emission properties of the overlying dots.
Social networking relationships, firm‐specific managerial experience and firm performance in a transition economy: A comparative analysis of family owned and nonfamily firms
Authors: Acquaah Moses 
Published: February 2012

AbstractThe effect of social networking relationships, firm‐specific managerial experience, and their interactions on performance between family owned and nonfamily firms are studied. Using data from 106 organizations in Ghana, the findings show that family owned firms benefit more from networking relationships with bureaucratic officials than do nonfamily firms. However, nonfamily firms benefit more from networking relationships with community leaders and firm‐specific managerial experience than do family owned firms. Networking relationships with politicians impede performance for nonfamily firms. Nonfamily firms are better able than family owned firms to use their firm‐specific managerial experience to manage the resources and capabilities obtained from networking relationships with community leaders to create value. Moreover, firm‐specific managerial experience attenuates the detrimental effects of networking with politicians for both types of firms. Copyright © 2012 John Wiley & Sons, Ltd.
Facile Synthesis of Au‐Nanoparticle/Polyoxometalate/Graphene Tricomponent Nanohybrids: An Enzyme‐Free Electrochemical Biosensor for Hydrogen Peroxide
Authors: Liu Rongji , Li Shiwen , Yu Xuelian , Zhang Guangjin , Zhang Suojiang , Yao Jiannian , Keita Bineta , Nadjo Louis , Zhi Linjie 
Published: February 2012

AbstractA green, facile, one‐pot synthesis of well‐defined Au NPs@POM–GNSs tricomponent nanohybrids is reported (POM stands for polyoxometalate and GNSs for graphene nanosheets). The synthesis is convenient, rapid and environmentally friendly. The POMs serve as both reducing, encapsulating molecules, and bridging molecules; this avoids the introduction of other organic toxic molecules. Characterization using transmission electron microscopy, X‐ray diffraction, X‐ray photoelectron spectroscopy, and Raman spectroscopy analysis is performed, and the structure of the prepared nanohybrids of Au NPs@POM–GNSs is verified. Most importantly, the amperometric measurements show the Au NPs@POM–GNSs nanohybrids have high catalytic activity with good sensitivity, good long‐term stability, wide linear range, low detection limit, and fast response towards H2O2 detection for application as an enzyme‐free biosensor. Transformation of the POMs during H2O2 detection does not affect the catalytic activities of the nanohybrids. Thus, the synergistic effect of Au NPs and GNSs in the nanohybrids leads to the enhanced catalytic property.