bluuebunny/crossref_metadata_2025_split huggingface dataset:
Plasma Polymerization of Polypyrrole‐Like Films on Nanostructured Surfaces
Authors: Yagüe Jose L. , Agulló Núria , Borrós Salvador 
Published: April 2008

AbstractIn this work, the deposition of polypyrrole thin films on nanostructured surfaces is reported. It has been demonstrated that the deposition and growth of polypyrrole is enhanced by the formation of a pyrrole‐terminated self‐assembled monolayer on a gold surface. Surface nanostructuration has been achieved by the self‐assembling technique and the deposition of the organic polymer by plasma‐enhanced chemical vapor deposition (PECVD) method. The effect of several ω‐(pyrrolyl)alkanethiol on the SAM formation, as well as the polymerization time to control the nucleation process have been studied. Thin films compositions have been characterized by AFM and XPS techniques. Conductive measurements of the samples were performed using the four point probe method.magnified image
Redox proteomics studies of in vivo amyloid beta‐peptide animal models of Alzheimer's disease: Insight into the role of oxidative stress
Authors: Sultana Rukhsana , Butterfield D. Allan 
Published: April 2008

AbstractAlzheimer's disease (AD) is an age‐related neurodegenerative disease. AD is characterized by the presence of senile plaques, neurofibrillary tangles, and synaptic loss. Amyloid β‐peptide (Aβ), a component of senile plaques, has been proposed to play an important role in oxidative stress in AD brain and could be one of the key factors in the pathogenesis of AD. In the present review, we discuss some of the AD animal models that express Aβ, and compare the proteomics‐identified oxidatively modified proteins between AD brain and those of Aβ models. Such a comparison would allow better understanding of the role of Aβ in AD pathogenesis thereby helping in developing potential therapeutics to treat or delay AD.
MicroRNA and proteome expression profiling in early‐symptomatic α‐synuclein(A30P)‐transgenic mice
Authors: Gillardon Frank , Mack Matthias , Rist Wolfgang , Schnack Cathrin , Lenter Martin , Hildebrandt Tobias , Hengerer Bastian 
Published: April 2008

AbstractThe α‐synuclein has been implicated in the pathophysiology of Parkinson's disease (PD), because mutations in the alpha‐synuclein gene cause autosomal‐dominant hereditary PD and fibrillary aggregates of alpha‐synuclein are the major component of Lewy bodies. Since presynaptic accumulation of α‐synuclein aggregates may trigger synaptic dysfunction and degeneration, we have analyzed alterations in synaptosomal proteins in early symptomatic α‐synuclein(A30P)‐transgenic mice by two‐dimensional differential gel electrophoresis. Moreover, we carried out microRNA expression profiling using microfluidic chips, as microRNA have recently been shown to regulate synaptic plasticity in rodents and to modulate polyglutamine‐induced protein aggregation and neurodegeneration in flies. Differentially expressed proteins in α‐synuclein(A30P)‐transgenic mice point to alterations in mitochondrial function, actin dynamics, iron transport, and vesicle exocytosis, thus partially resembling findings in PD patients. Oxygen consumption of isolated brain mitochondria, however, was not reduced in mutant mice. Levels of several microRNA (miR‐10a, ‐10b, ‐212, ‐132, ‐495) were significantly altered. One of them (miR‐132) has been reported to be highly inducible by growth factors and to be a key regulator of neurite outgrowth. Moreover, miR‐132‐recognition sequences were detected in the mRNA transcripts of two differentially expressed proteins. MicroRNA may thus represent novel biomarkers for neuronal malfunction and potential therapeutic targets for human neurodegenerative diseases.
Formation of nitride laser cavities with cleaved facets on transferred laser diodes on GaAs substrates
Authors: Yu Wen‐Chien , Ye Shu‐Mei , Hsiao Feng‐Ke , Lee Chi‐Ling , Lee Wei‐I 
Published: April 2008

AbstractSmoothly cleaved facets with high reflectivities have been demonstrated on GaN laser diodes after the devices were transferred onto GaAs substrates. The GaN based laser diode structure was first fabricated by metal organic chemical vapor deposition (MOCVD) on c‐plane sapphire substrates. The samples were then mounted onto thin GaAs substrates using wafer‐bonding technology. Laser lift‐off (LLO) technique was applied to remove the original sapphire substrate and transfer the GaN laser structure onto GaAs substrates. Since the cubic substrates have well‐defined laser cavity cleavage facet, the GaN structures bonded onto the substrates also formed smooth facets after cleavage. The cleaved facets of GaN laser diodes have been characterized using atomic force microscopy (AFM) with less than 2 nm roughness. The present study demonstrated the feasibility of transferring GaN laser structures onto other more appealing substrates for formation of laser cavities. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Estimation of internal quantum efficiency in InGaN‐based light emitting diodes using electroluminescence decay times
Authors: Saito Shinji , Narita Tetsuo , Zaima Kotaro , Tachibana Koichi , Nago Hajime , Hatakoshi Gen‐ichi , Nunoue Shinya 
Published: April 2008

AbstractWe investigate the internal quantum efficiency of InGaN‐based Light Emitting Diodes (LEDs) from the semiconductor rate equation of pulse current injection. A method is presented for estimating the internal quantum efficiency based on data of electroluminescence decay times measured as a function of current in the pulse injection. For the screening of built‐in electric field, the pulse current was injected with bias voltage. For blue LED, the internal quantum efficiency was measured to be about 70% in high injection condition. It is found that the internal quantum efficiency increase with injection current, whereas the external quantum efficiency decreases at high injection. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Effects of icariin combined with Panax notoginseng saponins on ischemia reperfusion‐induced cognitive impairments related with oxidative stress and CA1 of hippocampal neurons in rat
Authors: Zheng Ming , Qu Linhai , Lou Yijia 
Published: April 2008

AbstractPrevious studies suggest that treatment with icariin (ICA) combined with Panax notoginseng saponins (PNS) improved behavior and cholinergic system disorders followed by amyloid β‐peptide25−35 lateral ventricle injection in rats. The present study investigated whether administration of ICA + PNS had preventive and therapeutic effects on bilateral common carotid arteries (CCA) occlusion‐induced cerebral ischemia‐reperfusion (IR) injury in rats. Male Sprague‐Dawley rats were divided randomly as follows: sham‐operated, i.g. vehicle, ICA (5 mg/kg), PNS (40 mg/kg), ICA + PNS (2.5 + 20, 5 + 40 or 10 + 80 mg/kg), and ergoloid mesylate as a positive control (0.45 mg/kg) in model rats. Treatment was performed once a day for 7 days prior to ischemia. The rats were subjected to transient global IR induced by CCA occlusion in combination with intraperitoneal injection of sodium nitroprusside (2.0 mg/kg), then treated with ICA + PNS for another 14 days continuously. ICA + PNS significantly improved the rat passive avoidance task in step‐down paradigms, and spatial cognition in the eight‐arm radial maze, concomitant with an improvement of blood viscosity. Increased lipid peroxidation in brain after IR injury was observed, MDA being 0.56 ± 0.10 nmol/mg prot vs 0.48 ± 0.06 nmol/mg prot in the vehicle control (p < 0.05). Treatment with ICA + PNS 2.5 + 10, 5 + 40, 10 + 80 mg/kg produced a marked reduction in the MDA level to 0.46 ± 0.06, 0.42 ± 0.09 and 0.45 ± 0.08 nmol/mg prot, respectively vs 0.56 ± 0.10 nmol/mg prot in IR injury only control (p < 0.05, p < 0.01). A decrease in superoxide dismutase activity was observed in the brain of IR rats (the SOD activity being 72.75 ± 4.62 U/mg prot vs 80.97 ± 6.06 U/mg prot in control, p < 0.05). ICA + PNS 5 + 40 mg/kg prevented the IR injury mediated fall in superoxide dismutase activity being 78.90 ± 6.61 U/mg prot versus 72.75 ± 4.62 U/mg prot (p < 0.05). ICA + PNS tended to attenuate apoptosis in hippocampal CA1 pyramidal neurons. Either ICA or PNS treatment alone did not obviously improve cognitive impairment (except that lipid peroxidation was reduced by PNS‐treatment). The results indicated that ICA + PNS may ameliorate learning and memory deficit and blood viscosity by protecting neurons from oxidative stress in ischemic brain. Copyright © 2008 John Wiley & Sons, Ltd.
Antioxidant potential of selected Spirulina platensis preparations
Authors: Dartsch Peter C. 
Published: April 2008

AbstractRecent studies suggest that Spirulina, a unicellular blue‐green alga, may have a variety of health benefits and therapeutic properties and is also capable of acting as an antioxidant and antiinflammatory agent. In this study, a cell‐free and a cell‐based test assay were used to examine the antioxidant and antiinflammatory properties of four selected Spirulina platensis preparations: (1) Biospirulina, (2) SpiruComplex, a preparation with naturally bound selenium, chromium and zinc, (3) SpiruZink, a preparation with naturally bound zinc, (4) Zinkspirulina + Acerola, a preparation with naturally bound zinc and acerola powder. The cell‐free test assay used potassium superoxide as a donor for superoxide radicals, whereas the cell‐based test assay used the formation of intracellular superoxide radicals of functional neutrophils upon stimulation by phorbol‐12‐myristate‐13‐acetate as a model to investigate the potential of Spirulina preparations to inactivate superoxide radicals. In accordance with the recommended daily dosage, test concentrations ranging from 50 to 1000 µg/mL were chosen. The results showed a dose‐dependent inactivation of free superoxide radicals (antioxidant effect) as well as an antiinflammatory effect characterized by a dose‐dependent reduction of the metabolic activity of functional neutrophils and a dose‐dependent inactivation of superoxide radicals generated during an oxidative burst. The results demonstrate that the tested Spirulina preparations have a high antioxidant and antiinflammatory potential. Especially SpiruZink and Zinkspirulina + Acerola might be useful as a supportive therapeutic approach for reducing oxidative stress and/or the generation of oxygen radicals in the course of inflammatory processes. Copyright © 2008 John Wiley & Sons, Ltd.
Rates of phase transformations in mixed‐phase clouds
Authors: Korolev Alexei V. 
Published: April 2008

AbstractThis paper presents a theoretical framework describing the thermodynamics and phase transformations of a three phase component system consisting of ice particles, liquid droplets and water vapour. The instant rates of change of water (q̇w), ice (q̇i) and vapour (q̇v) mixing ratios are described based on the quasi‐steady approximation. The local thermodynamic conditions required for the equilibrium of liquid (q̇w = 0), ice (q̇i = 0) and vapour (q̇v = 0) phases are analysed. It is shown that there are four different regimes of the partitioning of water between liquid, ice, and gaseous phases in mixed clouds. The Wegener–Bergeron–Findeisen (WBF) process is identified as being relevant to two of those regimes. The efficiency of the WBF process in characterizing the capability of ice crystals to deplete the water evaporated from liquid droplets is introduced here. It is shown that the WBF process has maximum efficiency at approximately zero vertical velocity. The analysis of the dependences of q̇w, q̇i and q̇v on the vertical velocity, temperature, pressure and the integral radii of the cloud particles is presented. It is shown that the maximum rates of ice growth and droplet evaporation do not necessarily occur at T = − 12 °C where the maximum difference between saturation vapour pressure over ice and that over liquid is observed. Copyright © 2008 Crown in the right of Canada. Published by John Wiley & Sons, Ltd
Stability of some exact solutions of the shallow‐water equations for testing numerical models in spherical geometry
Authors: Staniforth A. , White A. A. 
Published: April 2008

AbstractFive families of exact axisymmetric solutions of the nonlinear shallow‐water equations in spherical geometry have recently been proposed as an aid to the development and testing of global numerical models. Sufficient conditions for the stability of these solutions are here derived to guide the choice of values for the family parameters. Thus it can be ensured that any significant time evolution occurring in a numerical model initialised with one of these exact solutions is of numerical origin, and does not reflect an inherent physical instability. With the caveat that only sufficient conditions for stability are examined, it appears that planetary rotation stabilises the solutions (as would be so if the flow were governed by barotropic vorticity dynamics), and that low Rossby and Froude numbers favour their stability. © Crown Copyright 2008. Reproduced with the permission of the Controller of HMSO. Published by John Wiley & Sons, Ltd
Ion yield improvement for static secondary ion mass spectrometry by use of polyatomic primary ions
Authors: De Mondt Roel , Van Vaeck Luc , Heile Andreas , Arlinghaus Heinrich F. , Nieuwjaer Nicolas , Delcorte Arnaud , Bertrand Patrick , Lenaerts Jens , Vangaever Frank 
Published: April 2008

AbstractStatic secondary ion mass spectrometry (S‐SIMS) is one of the potentially most powerful and versatile tools for the analysis of surface components at the monolayer level. Current improvements in detection limit (LOD) and molecular specificity rely on the optimisation of the desorption‐ionisation (DI) process. As an alternative to monoatomic projectiles, polyatomic primary ion (P.I.) bombardment increases ion yields non‐linearly. Common P.I. sources are Ga+ (liquid metal ion gun (LMIG)), SF (electron ionisation) and the newer Au, Bi (both LMIG) and C (electron ionisation) sources. In this study the ion yield improvement obtained by using the newly developed ion sources is assessed. Two dyes (zwitterionic and/or thermolabile polar functionalities on a largely conjugated backbone) were analysed as a thin layer using Ga+, SF, C, Bi+, Bi and Bi projectiles under static conditions. The study aims at evaluating the improvement in LOD, useful and characteristic yield and molecular specificity. The corrected total ion count values for the different P.I. sources are compared for different instruments to obtain a rough estimate of the improvements. Furthermore, tentative ionisation and fragmentation schemes are provided to describe the generation of radical and adduct ions. Characteristic ion yields are discussed for the different P.I. sources. An overview of the general appearances of the mass spectra obtained with the different P.I. sources is given to stress the major improvement provided by polyatomic P.I.s in yielding information at higher m/z values. Copyright © 2008 John Wiley & Sons, Ltd.
Editorial
Authors: Beaulieu Norman C. , Chen Hsiao‐Hwa , Sharif Hamid R. 
Published: April 2008

AbstractThe ever‐increasing demand for the services of wired and wireless data networks has led to network security being a prerequisite for all successful data transactions. This has accelerated research activities in academia, private sectors, and governments to respond to the challenges of providing complete solutions for secure communications and networks. Security and Communication Networks provides a distinctive global platform to explore the research advances in the communications network security from academia, industry, and governments. In this second issue, six thought provoking papers discussing various element of security research in communications and networks are presented. Copyright © 2008 John Wiley & Sons, Ltd.
Designing alliance networks: the influence of network position, environmental change, and strategy on firm performance
Authors: Koka Balaji R. , Prescott John E. 
Published: April 2008

AbstractAlliance networks are strategic decisions involving trade‐offs between two stylized structural design choices: prominent and entrepreneurial. Prominent alliance networks emphasize benefits arising out of multiple access and affiliation to other prominent firms in the network. An entrepreneurial position, on the other hand, emphasizes brokerage and diversity benefits arising out of access to nonredundant and diverse information. We demonstrate that the performance benefits of each type of alliance network are contingent on environmental change and strategy, and are thus time dependent. Following an environmental change event in the steel industry, alliance networks that were more entrepreneurial performed better, while those that were more prominent suffered performance decline. However, when the change was radical, both types of alliance networks were negatively related to performance. We suggest that following a radical change, industry alliance networks may not have the requisite information necessary for quick and effective strategic responses. Firms pursuing an analyzer strategy performed better when emphasizing a prominent, and to a lesser extent, entrepreneurial alliance network. However, firms that develop an alliance network high on both prominent and entrepreneurial structural positions had lower relative performance. Our results indicate the need for managers to assess their alliance portfolio over time and redesign it based on environmental and strategic contingencies. Copyright © 2008 John Wiley & Sons, Ltd.
Growth Kinetics of Gold Nanocrystals: A Combined Small‐Angle X‐Ray Scattering and Calorimetric Study
Authors: Biswas Kanishka , Varghese Neenu , Rao Chintamani N. R. 
Published: April 2008

AbstractThe growth of gold nanocrystals prepared by the reduction of tetrachloroauric acid by tetrakis(hydroxymethyl)phosphonium chloride, which allows slow reduction, is investigated by small‐angle X‐ray scattering and isothermal titration calorimetry in combination with transmission electron microscopy. The growth of the nanocrystals does not follow the diffusion‐limited Ostwald ripening but instead follows a sigmoidal rate curve. The activation energy obtained from the temperature‐dependent growth study is very small. The heat change associated with the growth is determined for the first time as approximately 10 kcal mol−1 per 1 nm increase in the nanocrystals' diameter.
Dramatic Improvements in Toughness in Poly(lactide‐co‐glycolide) Nanocomposites
Authors: Xu Wei , Raychowdhury Subhendu , Jiang David D. , Retsos Haris , Giannelis Emmanuel P. 
Published: April 2008

AbstractPoly(lactide‐co‐glycolide) (PLG), a biocompatible and biodegradable polymer, is dramatically toughened by adding small amounts of surface modified clay nanoparticles. The elongation during tensile tests increases from 7% for the pure polymer to 210% for the nanocomposite, accompanied with a modest increase in modulus. In contrast, PLG nanocomposites based on fumed silica treated with hexamethyldisilazane show only modest improvements in toughness. Electron microscopy, X‐ray scattering, rheometry, and dielectric relaxation spectroscopy are used to investigate the toughening mechanism. Multiple crazing occurs in the clay nanocomposite after yielding. Small angle X‐ray scattering studies show significant orientation of the clay nanoparticles along the tensile stress direction during deformation. The clay nanocomposites show a new, slow relaxation mode, most likely due to interfacial adsorbption of PLG chains on the surface of the clay nanoparticles. The dramatic increase in toughness is attributed to physical crosslinks introduced by the clay nanoparticles, a mechanism absent in the PLG/silica nanocomposites. The physical crosslinks increase the brittle fracture strength of the polymer and, consequently, trigger a toughening mechanism via multiple crazing and shear yielding.
Experimental Risk Estimation for Offshore Software Outsourcing
Authors: Sheng Zhongqi , Nakano Masayuki , Kubo Shingo , Tsuji Hiroshi 
Published: April 2008

AbstractIt is necessary to estimate the risk for strategic decision of offshore software outsourcing projects. In this paper we propose an experimental risk estimation method based on questionnaire for externalizing the know‐how of experienced project managers. Introducing three parts of questionnaire contents, this paper describes the estimation method and presents the implementation procedure. Focusing on five client companies, this paper reports five types of risk estimation methods considering the bias of respondents with different backgrounds, and discusses the Recall, Precision together with Accuracy of these estimation methods. This paper also applies the t‐test and vector analysis to study the bias in vendor countries, software types, as well as client companies. Copyright © 2008 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.
No‐Reference Image Quality Evaluation Model for JPEG and JPEG2000 Images
Authors: Parvez Sazzad Z. M. , Kawayoke Y. , Horita Y. 
Published: April 2008

AbstractIn this paper, we present a new no‐reference (NR) image quality evaluation model for Joint Photographic Experts Group (JPEG) and JPEG2000 coded images. The proposed model is based on the blockiness around the block boundary, average absolute difference between adjacent pixels within the block, and zero‐crossing (ZC) rate within the block of the image. Subjective experimental results of the Laboratory for Image and Video Engineering (LIVE) Image Quality Assessment Database were used to train and test the model, which achieved sufficient quality prediction performance. Copyright © 2008 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.
Preoperative local staging of endometrial cancer: transvaginal sonography vs. magnetic resonance imaging
Authors: Savelli L. , Ceccarini M. , Ludovisi M. , Fruscella E. , De Iaco P. A. , Salizzoni E. , Mabrouk M. , Manfredi R. , Testa A. C. , Ferrandina G. 
Published: April 2008

AbstractObjectivesTo compare the accuracy of transvaginal sonography (TVS) and magnetic resonance imaging (MRI) in the preoperative staging of endometrial carcinoma.MethodsThis was a prospective study in which 74 women consecutively diagnosed with endometrial carcinoma were examined using TVS by physicians trained in gynecological sonography and MRI by radiologists with a special interest in gynecology. All patients underwent surgical–pathological staging after removal of the uterus, adnexa and pelvic lymph nodes. Sensitivity, specificity, and positive and negative predictive values were calculated for each imaging modality with regard to detection of neoplastic invasion of the outer half of the myometrium and cervical involvement.ResultsTVS and MRI performed equally well in the preoperative staging of endometrial cancer, with no statistically significant differences between the two techniques. The sensitivity, specificity, positive and negative predictive values, and overall diagnostic accuracy for TVS in the evaluation of myometrial infiltration were 84%, 83%, 79%, 88% and 84%, respectively. Respective values for MRI were 84%, 81%, 77%, 87% and 82%. The corresponding statistics for detection of cervical involvement were 93%, 92%, 72%, 98% and 92% for TVS; and 79%, 87%, 58%, 95% and 85% for MRI.ConclusionsWhen carried out by expert practitioners, TVS shows good accuracy in the local staging of endometrial carcinoma. Because of its high costs, MRI should be offered only to those in whom TVS produces images of poor quality. Copyright © 2008 ISUOG. Published by John Wiley & Sons, Ltd.