bluuebunny/crossref_metadata_2025 huggingface dataset:
Introduction: Actions of Transfer
Authors: CASE SUE-ELLEN , TAYLOR DIANA
Published: May 2010

Our co-authored article provides an introduction to the UCLA-based conference Actions of Transfer: Women's Performance in the Americas (2008), a sister event to the opening of the new cultural and performance space with FOMMA – Fortaleza de la Mujer Maya (Fortress of the Mayan Woman) – supported by the Hemispheric Institute and the Ford Foundation. Introducing the articles and contributions to the performance dossier arising out of the event and brought together for this special issue, we reflect critically on our conference set-up. Detailing our multi-sited project as a dialogic, hemispheric practice, we offer our reflections with the hope that this will lead to new possibilities and paradigms for international performance research and practice.
Performing Ri(gh)t(e)s: (W)Riting the Native (In and Out of) Ceremony
Authors: HERNÁNDEZ-AVILA INÉS
Published: May 2010

This article considers Native American/indigenous (women's) theatre from the perspective of performing indigeneities/embodied spiritualities, in relation to ceremonial and ‘cotidian’ ri(gh)t(e)s, and the practice of personal and collective autonomy as a ri(gh)t(e). I situate my discussion within particular sites of the performance of indigeneity and the embodiment of spirituality in Chiapas, Mexico, where my research has taken me, within my own work with a performance course I created at the University of California, Davis, and within critical perspectives offered in Native American studies. I also provide some commentary on the two related gatherings that took place at the Centro Hemisférico/FOMMA, in San Cristobal de las Casas, Chiapas, August 2008, and the Actions of Transfer: Women's Performance in the Americas conference at UCLA, November 2008. Both events were co-sponsored by the Hemispheric Institute on Performance and Politics of NYU and they were announced on the UCLA website as ‘sister’ events. In August 2008, FOMMA officially became a ‘branch’ centre of the Hemispheric Institute.
Kant's Transcendental Idealism
Authors: Bird Graham
Published: May 2010

The whole of our human experience is determined by certain material conditions which cannot themselves be a part of that experience. In particular there exist objects, inaccessible to our senses, which nevertheless interact with ourselves to produce that experience. But the selves which are so affected by these objects outside our experience, and the internal mechanisms which somehow construct that experience, are also just such material conditions of, and not parts of, that experience. We might describe this appeal to material conditions of experience in Kant's technical terms as the ‘intelligible’ or even ‘transcendental’ background to our empirical experience. In its attempt to provide some explanation, in terms of things in themselves, of empirical objects (whether physical things or persons) it forms a central part of what Adickes called Kant's ‘double affection’ theory.
Global Householding amid Global Crises
Authors: Peterson V. Spike
Published: May 2010

Households are an enduring feature of human history. They are the building blocks of social formations in every era and at all scales: from small communities to the global economy. Like families, they “order” social relations in particular ways. But households differ from families by allowing for nonkinship members and by not presuming shared group residence. The emphasis lies, rather, in the pooling of diverse (material and nonmaterial) resources with the purpose of ensuring the continuity of the collective unit. Michael Douglass (2006, 423) deploys the term householding to underscore how “creating and sustaining a household is a continuous process of social reproduction that covers all life-cycle stages and extends beyond the family.” Global householding references the many ways in which these processes increasingly occur across national boundaries, for example, through transborder marriages, overseas education, labor migration, and war displacements. The psychological, sociocultural, economic, and political implications of these processes are extraordinarily complex and arguably involve as much as one-quarter of the world's population.
Influence of midlatitude sporadic E layer patches upon the F region plasma density
Authors: Shalimov S. , Yamamoto M.
Published: May 2010

Polarization electric fields of the Es patches on scales above about 10 km can map efficiently between the E and F regions. We propose a simple quantitative model in which the electrical coupling between the dense band‐like Es patch and the F region depends on the presence of field‐aligned closure currents and the orientation of the ambient effective electric field relative to the band and results in corresponding F region plasma density redistribution caused by E region polarization processes. Specifically, we show that for the representative ratio of Pedersen conductances inside and above the sporadic E patch and typical values of the ambient effective electric field, strong depletions in F layer plasma density can be produced by the patch's polarization electric field that maps up to the F region.
On the nature of winter cooling and the recent temperature shift on the northern Gulf of Alaska shelf
Authors: Janout Markus A. , Weingartner Thomas J. , Royer Thomas C. , Danielson Seth L.
Published: May 2010

In spring 2006 and 2007, northern Gulf of Alaska (GOA) shelf waters were ∼1.5°C below average throughout the ∼250 m deep shelf and the salinity‐dependent winter stratification was anomalously weak due to above (below) average surface (bottom) salinities. Spring 2007 and 2008 temperatures were also ∼−1.5°C below average, but the anomalies were confined to the upper 100 m due to moderate salt stratification. Shelf temperatures in these 2 years were among the lowest observed since the early 1970s, thus interrupting an approximately 30‐year warming trend. We examined winter cooling processes using historical conductivity‐temperature‐depth (CTD) profiles and mooring data from hydrographic station GAK1. The 2006 and 2007 cooling was associated with anomalously strong atmospheric heat loss in November 2006 and March 2007 and below‐average fall runoff, which weakened winter stratification and allowed the late cooling to penetrate throughout the water column. In 2007 and 2008, early winter cooling was weak, fall runoff large, and stratification moderate at 100 m so that spring temperature anomalies were trapped to the upper 100 m. Analysis of the 40 year GAK1 CTD record indicates that winter averaged air‐sea heat flux and salinity stratification anomalies explain 81% of the variation in deep (100–250 m) GOA temperatures. Although the timing and magnitude of winter runoff influences the shelf temperature distribution, temperature anomalies are a consequence of three‐dimensional circulation and mixing processes. These involve the complex, but poorly understood, interplay among the air‐sea heat flux; the ocean heat flux convergences; the stabilizing influence of runoff; and the destabilizing effects of cooling, vertical mixing, and the wind‐driven cross‐shelf buoyancy flux.
HBcAg induces interleukin‐10 production, inhibiting HBcAg‐specific Th17 responses in chronic hepatitis B patients
Authors: Li Jie , Wu Wei , Peng Guoping , Chen Feng , Bai Minghui , Zheng Min , Chen Zhi
Published: May 2010

T‐helper (Th) 17 cells have been shown to have an important role in host defense against viral infection. However, little is known about the regulation of Th17 cells in hepatitis B virus (HBV) infections. Peripheral blood mononuclear cells (PBMCs) isolated from patients with chronic hepatitis B (CHB) were stimulated with anti‐interleukin (IL)‐10 antibody or recombinant IL‐10. The frequency of hepatitis B core antigen (HBcAg)‐specific Th17 cells was characterized and produced cytokines were determined by flow cytometry. A low frequency of Th17 cells and a high frequency of Th1 cells were detected in CHB patients. HBcAg stimulation promoted IL‐17A, IL‐22, IL‐23, IL‐6, transforming growth factor (TGF)‐β and IL‐10 production by PBMCs from CHB patients, but not from healthy controls. Furthermore, endogenous IL‐10 inhibited HBcAg‐stimulated production of IL‐17A, IL‐22, IL‐6 and IL‐23, but not TGF‐β. Treatment with IL‐10 inhibited the HBcAg‐stimulated activation of Th17 cells, whereas anti‐IL‐10 antibody significantly increased the frequency of Th17 and Th1 cells, but not that of CD4+CD25+ regulatory T cells, associated with upregulating RORγt expression in CD4+ T cells. HBcAg stimulated the production of IL‐10, which negatively regulated HBcAg‐specific Th17 cell responses in CHB patients. Our findings may represent one evasion strategy for HBV to subvert specific antiviral responses in humans.
Convergence in probiotic Lactobacillus gut-adaptive responses in humans and mice
Authors: Marco Maria L , de Vries Maaike C , Wels Michiel , Molenaar Douwe , Mangell Peter , Ahrne Siv , de Vos Willem M , Vaughan Elaine E , Kleerebezem Michiel
Published: May 2010

Probiotic bacteria provide unique opportunities to study the global responses and molecular mechanisms underlying the effects of gut-associated microorganisms in the human digestive tract. In this study, we show by comparative transcriptome analysis using DNA microarrays that the established probiotic Lactobacillus plantarum 299v specifically adapts its metabolic capacity in the human intestine for carbohydrate acquisition and expression of exopolysaccharide and proteinaceous cell surface compounds. This report constitutes the first application of global gene expression profiling of a commensal microorganism in the human gut. A core L. plantarum transcriptome expressed in the mammalian intestine was also determined through comparisons of L. plantarum 299v activities in humans to those found for L. plantarum WCFS1 in germ-free mice. These results identify the niche-specific adaptations of a dietary microorganism to the intestinal ecosystem and provide novel targets for molecular analysis of microbial–host interactions which affect human health.
Paleoecology of the Maastrichtian and Danian sediment at North of Central Alborz, Iran, based on Planktonic foraminifera
Authors: Balmaki Behnaz
Published: May 2010

In order to study the fossil contents of the Ziarat-kola section for biostratigraphical purposes the 212 meters was sampled at Central Alborz. The sequence is mainly made up of monotonous grey- green to light grey marl. Based on Planktonic foraminifera age of Maastrichtian-Danian is determined to the section.Four zones were determined by the benthic foraminifera morphogroup for showing oxygen and productivity change. The approximate low oxygen and high food supply has been indicates zone of one that increase infauna to epifauna morphotype percent is low (nearness 60% infouna, 40% epifauna). In zone two, with due attention to equal percent of Epifauna ratio to infauna, intermediate oxygen and food supply is anticipated. The decrasing epifauna foraminifera and increasing infauna demonstrates low oxygen and high food supply condition at zone of three. In zone four, increasing epifauna (approximate 90 percent) that are indicated high oxygen condition and low food supply. Analysis of planktonic foraminifera assemblage at this section with Cretaceous biostratigraphical provinces is indicating a close similarity with Tethyan provinces.
The community of herbivorous arthropods as an indicator for biological control function in the Post Market Environmental Monitoring of the cultivation of stacked Bt maize
Authors: Schultheis Eva , Slusarenko Alan , Rauschen Stefan
Published: May 2010

In field experiments on the potential impacts of the genetically engineered Bt maize events MON 810, MON 88017, and MON 89034 x MON 88017, data were gathered on a diverse range of non-target organisms (NTO). These experiments were performed at different trial locations since 2001.Surveying herbivores serves two purposes: (i) to assess direct effects on these NTO, and (ii) indirectly analyse disturbances in the biological control function of natural enemies (Sanvido et al., 2009).Herbivores of interest for this approach should be exposed to the Bt proteins, representative for the maize biocoenosis, and of considerable densities using standardised methods.Plant bugs (Heteroptera: Miridae), plant- and leafhoppers (Auchenorrhyncha), and flowervisiting arthropods such as thrips (Thysanoptera) were chosen as potential canditate groups.To evaluate the abundances of these insects, the herb layer was sampled using sticky traps and sweep netting. Maize panicles were sampled during anthesis. The data demonstrate that there is a prevalent community of herbivores in maize, dominated by a few species that can be surveyed over the whole growing season using the methods employed.
Development and validation of a method for the detection of altered resistance in transgenic plants against herbivore-pathogen-complexes
Authors: Drechsler Nadine , Habekuß Antje , Thieme Thomas , Schubert Jörg
Published: May 2010

Enhanced or reduced uptake of viruses by vectors and changes in resistance level can be sensitive indicators for metabolic changes in transgenic plants caused by the new trait and not observed by conventional methods. In addition, the plant transformation process itself can lead to such changes. To be able to investigate this hypothesis in cereals we decided to use two highly important insect-transmitted viruses infecting them - Barley yellow dwarf virus (BYDV) and Wheat dwarf virus (WDV). Corresponding molecular tools for their quantification in plants as well as virus vectors had to be developed. Both viruses cause similar symptoms: dwarfing, stunting, leaf discoloration leading to yield losses or death of plant. BYDV (Luteoviridae) is one of the most important cereal-infecting viruses worldwide causing substantial yield losses. In Germany, the strain PAV is widespread. It is transmitted by the aphids Rhopalosiphum padi and Sitobion avenae in a persistent manner. WDV (Geminiviridae) is found in Germany since the early 1990s and has gained importance over the last years. It is transmitted by the leafhopper Psammotettix alienus in a persistent manner. Real-time PCR is the state of the art method for specific detection of viruses even in minor quantities. It allows exact quantification of the virus content of plants and vectors and is hence suited to monitor changes of it. We developed qPCR assays for WDV and RT-qPCR assays for BYDV-PAV based on TaqMan probe technology as well as the DNA-binding dye SybrGreen. The qPCR assays proved to be more sensitive than DAS-ELISA. For example, WDV is detected even at dilutions of 1:10^8^, whereas the corresponding threshold for ELISA is about 1:10^4^. As nucleic acid extraction procedures proved to be time consuming and expensive, detection methods are adopted now for immunocapture procedures. These methods will be applied to the analysis of several transgenic wheat lines.
Inflammation Correlates With Markers of T‐Cell Subsets Including Regulatory T Cells in Adipose Tissue From Obese Patients
Authors: Zeyda Maximilian , Huber Joakim , Prager Gerhard , Stulnig Thomas M.
Published: May 2010

Accumulation of cytotoxic and T‐helper (Th)1 cells together with a loss of regulatory T cells in gonadal adipose tissue was recently shown to contribute to obesity‐induced adipose tissue inflammation and insulin resistance in mice. Human data on T‐cell populations in obese adipose tissue and their potential functional relevance are very limited. We aimed to investigate abundance and proportion of T‐lymphocyte sub‐populations in human adipose tissue in obesity and potential correlations with anthropometric data, insulin resistance, and systemic and adipose tissue inflammation. Therefore, we analyzed expression of marker genes specific for pan‐T cells and T‐cell subsets in visceral and subcutaneous adipose tissue from highly obese patients (BMI >40 kg/m2, n = 20) and lean to overweight control subjects matched for age and sex (BMI <30 kg/m2; n = 20). All T‐cell markers were significantly upregulated in obese adipose tissue and correlated with adipose tissue inflammation. Proportions of cytotoxic T cells and Th1 cells were unchanged, whereas those of regulatory T cells and Th2 were increased in visceral adipose tissue from obese compared to control subjects. Systemic and adipose tissue inflammation positively correlated with the visceral adipose abundance of cytotoxic T cells and Th1 cells but also regulatory T cells within the obese group. Therefore, this study confirms a potential role of T cells in human obesity‐driven inflammation but does not support a loss of protective regulatory T cells to contribute to adipose tissue inflammation in obese patients as suggested by recent animal studies.
Rosiglitazone attenuates development of polycystic kidney disease and prolongs survival in Han:SPRD rats
Authors: Dai Bing , Liu Yawei , Mei Changlin , Fu Lili , Xiong Xishan , Zhang Yan , Shen Xuefei , Hua Zhenhao
Published: May 2010

Although pioglitazone, a PPAR-γ (peroxisome-proliferator-activated receptor-γ) agonist, has been shown to prolong survival in two rapidly progressive pkd1 (polycystic kidney disease 1)-knockout mice models through disparate mechanisms, these studies lacked data on therapeutic potential and long-term safety because of a short observation period. In the present study, we have used another potent PPAR-γ agonist, rosiglitazone, to treat Han:SPRD rats, a slowly progressive ADPKD (autosomal dominant PKD) animal model, and confirmed that short-term treatment was able to delay the progression of kidney cysts and protect renal function, which may relate to down-regulating the abnormally activated β-catenin signalling pathway and its anti-inflammatory and anti-fibrosis effects. Long-term administration significantly prolonged the survival of Han:SPRD rats. Moreover, early therapy in rats with normal renal function had a better outcome than delayed therapy, while initiating therapy in rats with mild impaired renal function still protected renal function. The efficacy of rosiglitazone depended on continuous drug administration; withdrawal of the drug caused accelerated deterioration of renal function in effectively treated rats and shortened their survival to an untreated state. Long-term administration led to cardiac enlargement, probably due to rosiglitazone-mediated sodium re-absorption. In conclusion, these results indicate that rosiglitazone was able to effectively delay the progression of kidney disease and protect renal function in Han:SPRD rats, but its adverse effect of inducing cardiac enlargement should also be monitored closely.
Macroscopic Aharonov–Bohm effect in superconductors
Authors: Polyektov Yu. M.
Published: May 2010

The problems of the influence of the vector-potential field produced by a finite-radius solenoid on a superconducting medium outside the solenoid and on a hollow superconducting cylinder inside of which the solenoid is located are solved in the framework of the Ginzburg–Landau theory for type-II superconductors. The dependence of the magnetic flux in the solenoid on the surface current density in its winding is found, and it is shown that there exist regions of magnetic flux values that cannot be realized at any current density in the solenoid. In the case when the solenoid radius is significantly greater than the magnetic field penetration depth, this dependence has the form of a step function with a step height equal to the magnetic flux quantum and a width that is a “quantum of surface current density.” The change of the superconducting transition temperature in a cylinder outside the solenoid is found as a function of the surface current density in the solenoid.
Localization effects and pseudogap state in YBa2Cu3O7−δ single crystals with different oxygen content
Authors: Obolenskii M. A. , Vovk R. V. , Bondarenko A. V. , Chebotaev N. N.
Published: May 2010

We have investigated the evolution of the temperature dependence of the in-plane and off-plane conductivity of YBa2Cu3O7−δ single crystals due to the decrease of the oxygen content in the samples caused by a heat treatment. The concentration dependence of the in-plane and off-plane energy gaps has been determined. It has been shown that the enhancement of the localization effects results in a suppression of the pseudogap state. At the same time, the decrease of the oxygen content results in a relative narrowing of the temperature interval in which the regime of fluctuation conductivity is realized.
Fluctuation conductivity and pseudogap in Y1−xPrxBa2Cu3O7−y films
Authors: Solovjov A. L. , Dmitriev V. M.
Published: May 2010

The fluctuation conductivity (FC) and pseudogap (PG) in Y1−xPrxBa2Cu3O7−y with x≈0.1 are investigated. It is shown that the temperature dependence of the FC is the same as in YBa2Cu3O7−y containing defects. At the same time, the temperature dependence of the PG differs from the analogous dependence obtained for YBa2Cu3O7−y films. An increase of the coherence length and decrease of the characteristic temperature T* in Y1−xPrxBa2Cu3O7−y is observed with increasing Pr concentration.
Laser scanning microscopy of HTS films and devices (Review Article)
Authors: Zhuravel A. P. , Sivakov A. G. , Turutanov O. G. , Omelyanchouk A. N. , Anlage Steven M. , Lukashenko A. , Ustinov A. V. , Abraimov D.
Published: May 2010

The capabilities of laser scanning microscopy (LSM) as a spatially-resolved method of testing high-Tc superconductivity (HTS) materials and devices are described. The earlier results obtained by the authors are briefly reviewed. Some novel applications of LSM are illustrated, including imaging the HTS responses in rf mode, probing the superconducting properties of HTS single crystals, and development of two-beam laser scanning microscopy. The existence of the phase slip lines mechanism of resistivity in HTS materials is proven by LSM imaging.
Influence of high pressure on the fluctuation conductivity of YBa2Cu3O7−δ single crystals with an oxygen deficiency
Authors: Obolenskii M. A. , Vovk R. V. , Bondarenko A. V.
Published: May 2010

The influence of high hydrostatic pressure of up to 11kbar on the fluctuation conductivity of YBa2Cu3O7−δ single crystals with an oxygen deficiency δ≈0.5 and a critical temperature tc≈50K is investigated. It is found that for these samples, unlike samples of stoichiometric composition, the application of high pressure leads to a decrease of the coherence length perpendicular to the ab plane, ξc(0). It is shown that the pressure-induced redistribution of the labile oxygen causes a shift of the temperature interval in which three-dimensional superconducting fluctuations exist.
Behavior of the Elements at High Pressures
Authors: Cannon John Francis
Published: May 2010

Data on polymorphic phase changes and variation of melting temperature of the elements with pressure have been compiled and critically evaluated. Emphasis has been placed on work done at pressures exceeding 1 kbar. Pressure-temperature phase diagrams showing first-order solid-solid phase boundaries and/or melting curves derived from the best available data are given for 58 elements. Information on the crystal structures of high-pressure polymorphs is also reviewed. Those elements that exist in the gaseous state at room temperature and pressure are not included.
Theoretical calculations of hydrogen adsorption by SnO2 (110) surface: Effect of doping and calcination
Authors: Inerbaev Talgat M. , Kawazoe Yoshiyuki , Seal Sudipta
Published: May 2010

A pseudopotential plane-wave based density functional theory simulations of the hydrogen adsorption on rutile SnO2 (110) surface is reported. It is found that on doping with trivalent indium, the surface becomes unstable due to the formation of bridging oxygen vacancies. At sufficiently low doping level, the surface stabilizes at an oxygen vacancy to indium ratio of 1:2. Our calculations predict that at a higher doping level of 9 at. %, this ratio becomes larger, and point out a way to synthesize p-type conducting SnO2 thin films. The binding energy of SnO2 (110) surface with adsorbed hydrogen atoms display a maximum at 3–6 at. % of indium doping. This is in good agreement with the experimental results obtained from the SnO2-based hydrogen sensor’s sensitivity measurements given by Drake et al. [J. Appl. Phys. 101, 104307 (2007)]. The theoretical modeling explains that the calcinations treatment can critically affect the sensitivity of the hydrogen sensor due to the enhancement of the binding energy between the SnO2 surface and the adsorbed hydrogen atoms.
Shape dependence of the intrinsic quantum shot noise suppression of electron field emission
Authors: Pant M. , Ang L. K.
Published: May 2010

This paper presents a two-dimensional nonuniform model to calculate the quantum shot noise suppression (or Fano factor) for electron field emission from a single field emitter of two different shapes: Lorentzian and prolate spheroidal. Between them, the Lorentzian field emitter has a larger shot noise suppression. For a given sharp emitter at a fixed work function, there is a minimum value of the Fano factor, which is independent of the geometrical sharpness of the emitter, and it increases with larger work function. Comparison with the one-dimensional uniform model has implied that prior results had overestimated the shot noise suppression.
Polaron conduction in Lix[Ni1/3Mn1/3Co1/3]O2−δ (x=1, 0.9 and δ=, 0.05) cathodes
Authors: Kabi S. , Ghosh A.
Published: May 2010

The dc conductivity measured in a wide range of temperature (93–373 K) for the electrode compounds Lix[Ni1/3Mn1/3Co1/3]O2−δ (x=1, 0.9 and δ=0, 0.05) is reported in this paper. The dc conductivity data have been analyzed in the framework of theoretical models for polaronic conduction. The analysis shows that in the low temperature range (93–163 K) the dc conductivity data are consistent with the variable range hopping model and from the fits of experimental data the density of localized states at Fermi level for different compositions have been estimated. We have explained the temperature dependence of the conductivity employing polaron hopping models, proposed by Schnakenberg and Emin and co-workers, which consider the coupling of polarons with optical and acoustic phonon modes. The value of estimated polaron bandwidth indicates that polaron hopping process is nonadiabatic in nature. The parameters obtained from the fits of this model are reasonable.
Observation of hole hopping via dopant in MoOx-doped organic semiconductors: Mechanism analysis and application for high performance organic light-emitting devices
Authors: Qiao Xianfeng , Chen Jiangshan , Li Xinglin , Ma Dongge
Published: May 2010

Conduction mechanism in molybdenum trioxide (MoOx)-doped hole- and electron-type organic semiconductors is investigated. The used hole-transporting materials are N,N′-diphenyl-N,N′-bis(1-naphthylphenyl)-1, 1′-biphen4, 4′-diamine, 4′,4″-tri(N-carbazolyl)triphenylamine, 4, 4′-N,N-dicarbazole-biphenyl, and pentacene and the used electron-transporting material is (8-quinolinolato) aluminum (Alq3). It can be seen that the hole conductivity is significantly enhanced upon MoOx doping, and more importantly, dominant hole current could be realized in a typical electron-transport material Alq3 by doping MoOx. Hence, high efficiency organic light-emitting devices can also be achieved even using MoOx-doped Alq3 film as hole transporting layer. The mechanism investigation indicates that the MoOx plays an important role in the hole transport. It is showed that the MoOx serves as the hole hopping sites, whereas the used organic materials serve as the transport medium and determine the magnitude of transport current. Furthermore, it is found that doping MoOx into the organic materials also reduces the energy and position disorders of the doped organic films, which are well demonstrated by the study on transport characteristics of the doped films at various temperatures.
A comparison of ion transport in different polyethylene oxide–lithium salt composite electrolytes
Authors: Karmakar A. , Ghosh A.
Published: May 2010

Polyethylene oxide (PEO) and lithium salts (LiI, LiClO4, and LiCF3SO3) based composite polymer electrolytes have been prepared for different [EO]/[Li] ratio using solution casting method and characterized by x-ray diffraction (XRD), scanning electron microscope, and differential scanning calorimetry (DSC). The electrical measurements have been carried out at different temperatures. XRD patterns, field emission scanning electron micrographs, and DSC clearly depict that amorphous region in the PEO–LiClO4 composite electrolyte with [EO]/[Li]=9 is dominant over the other electrolytes. It has been observed that the electrical conductivity of the PEO–LiClO4 electrolyte is higher than that of the PEO–LiI and PEO–LiCF3SO3 composite electrolytes. It has been also observed that the hoping rate of charge carriers for the PEO–LiClO4 electrolyte is higher than that of the other two electrolytes. The concentration of charge carriers is not thermally activated and the mobility controls the temperature dependence of electrical properties. Scaling of the conductivity spectra has been performed in order to get insight into the relaxation mechanisms.
Nature of ferroelectric to paraelectric phase transition in multiferroic 0.8BiFeO3–0.2Pb(Fe1/2Nb1/2)O3 ceramics
Authors: Patel Jay Prakash , Singh Anar , Pandey Dhananjai
Published: May 2010

We present here the results of high temperature powder x-ray diffraction study on 0.8BiFeO3–0.2Pb(Fe1/2Nb1/2)O3, which is isostructural with the well known multiferroic BiFeO3 (BF). It is shown that the room temperature ferroelectric phase of 0.8BF–0.2PFN in the R3c space group transforms to the paraelectric/paraelastic cubic (Pm3¯m) phase directly without any intermediate “β” phase reported in the literature for pure BF. This transition is of first order type as confirmed by the coexistence of R3c and Pm3¯m phases over a 100 K range and discontinuous change in the unit cell volume.
Magnetic alignment of Ni-coated single wall carbon nanotubes in heat transfer nanofluids
Authors: Horton Mark , Hong Haiping , Li Chen , Shi Bo , Peterson G. P. , Jin Sungho
Published: May 2010

Thermal conductivity (TC) of heat transfer nanofluids containing magnetic-metal-coated carbon nanotubes can be significantly enhanced (>60%) by applied magnetic field. In this paper, we report the observed real images of Ni-coated single wall carbon nanotubes in water and oils (polyalphaolefin, polyol ester) under magnetic field by high speed microscopy, and correlate them with TC measurements. Initially, the nanotubes are randomly dispersed in the fluid, however, on longer holding in magnetic field the nanotubes gradually stretch and are finally aligned. The chain length in the images is found to be around 30∼150 μm, which is much longer than the real length of individual nanotubes (5∼40 μm), indicating that nanotubes are aligned and form some chains and clusters. Because of the semicontinuous nature of Ni magnetic nanoparticles, as well as the viscosity resistance of the fluid itself, it takes some time for the Ni-coated nanotubes to respond to the applied magnetic field and align. Time dependent TC experiments indicate that alignment process dominates the TC enhancement rather than microconvection. Finally, scanning electron microscopy images also show that the Ni coated nanotubes are aligned well under the influence of a magnetic field. Transmission electron microscopy images indicate that nickel remains stable and attached onto the nanotubes after the magnetic field exposure and movements.
Effect of acceptor concentration on the bulk electrical conduction in acceptor (Mg)-doped BaTiO3
Authors: Yoon Seok-Hyun , Randall Clive A. , Hur Kang-Heon
Published: May 2010

Bulk electrical conductivity of acceptor (Mg)-doped BaTiO3 ceramics were evaluated via an impedance spectroscopy analysis for materials with Mg concentrations up to 0.6 mol % and over a temperature range of 120–540 °C. At high temperatures beyond 320 °C, the activation energies of the bulk electrical conduction (Eσ) slightly decreased from 1.2 to ∼1.0 eV with an increase in the Mg concentration. However, in the low temperature range below 320 °C, there is a continuous decreased from 1.2 eV and then this saturated to ∼0.4 eV with the increase in Mg concentration. The calculated bulk conductivities based on a defect chemistry model explains conductivity for temperatures above 320 °C. The model demonstrates a predominant electronic conduction in the low concentration range below 0.1 mol % Mg and mixed conduction with ionic and electronic carriers in the intermediate and in high acceptor concentration range of 0.2–0.6 mol % Mg. However, the decrease in Eσ with the increase in Mg concentration in the low temperature range could not be explained by the defect chemical model. Such deviation however could be explained by a transition to hopping conduction between ionized acceptor (MgTi″) and neutral or hole-trapped acceptor (MgTi×) with the increase in Mg concentration in the low temperature range.
Atomic force microscopy study of the growth mechanisms of nanostructured sputtered Au film on Si(111): Evolution with film thickness and annealing time
Authors: Ruffino F. , Grimaldi M. G.
Published: May 2010

Nanostructured Au films were deposited on Si(111) by room-temperature sputtering. By the atomic force microscopy technique we studied the evolution of the Au film morphology as a function of the film thickness h and annealing time t at 873 K. By the study of the evolution of the mean vertical and horizontal sizes of the islands forming the film and of their fraction of covered area as a function of h from 1.7×1017 to 1.0×1018 Au/cm2 we identified four different growth stages such as: (1) 1.7×1017≤h≤3.0×1017 Au/cm2, nucleation of nanometric three-dimensional (3D) hemispherical Au clusters; (2) 3.0×1017<h≤5.2×1017 Au/cm2, lateral growth of the Au clusters; (3) 5.2×1017<h≤7.7×1017 Au/cm2, coalescence of the Au clusters; (4) 7.7×1017<h≤1.0×1018 Au/cm2, vertical growth of the coalesced Au clusters. The application of the dynamic scaling theory of growing interfaces allowed us to calculate the dynamic scaling exponent z=3.8±0.3, the dynamic growth exponent β=0.38±0.03, the roughness exponent α=1.4±0.1 and the Avrami exponent m=0.79±0.02. Finally, the study of the evolution of the mean Au clusters size as a function of annealing time at 873 K allowed us to identify the thermal-induced self-organization mechanism in a surface diffusion limited ripening of 3D structures and also the surface diffusion coefficient of Au on Si(111) at 873 K was estimated in (8.2×10−16)±(3×10−17) m2/s.
Hyper-sensitive piezophotovoltaic effects in ferroelectric nanocylinders
Authors: Zheng Yue , Woo C. H.
Published: May 2010

Photocurrent system of the ferroelectric nanocylinder (FNC), including nanodisks, nanorods, and nanowires, sandwiched between metal electrodes with the short-circuit boundary conditions has been designed and investigated. Taking into account the polarization charge screening in the electrodes and near-surface inhomogeneous polarization distribution, a theoretical model for investigating the photoinduced current of the FNC under the illumination of light was established. Our results show that the photocurrent of the FNC can be totally controlled by adjusting its size and states of the polarization “up” and “down.” Especially, reversing an applied stress can obviously change the photocurrent of the FNC, which is particularly significant near the stress-dependent para/ferroelectric phase transition. This piezophotovoltaic effect may have good potential for applications in high-sensitivity photomechanical sensors, memories, switchable nanodevices, or other photovoltaic nanodevices.
Nonlinear response of a neoclassical four-field magnetic reconnection model to localized current drive
Authors: Lazzaro E. , Comisso L. , Valdettaro L.
Published: May 2010

In tokamaks magnetic islands arise from an unstable process of tearing and reconnecting of helical field lines across rational surfaces. After a linear stage the magnetic instability develops through three characteristic nonlinear stages where increasingly complex topological alterations occur in the form of the magnetic islands. The problem of response of reconnection process to the injection of an external current suitably localized is addressed using a four-field model in a plane slab plasma, with a novel extension to account consistently of the relevant neoclassical effects, such as bootstrap current and pressure anisotropy. The results found have implications on the interpretation of the possible mechanism of present day experimental results on neoclassical tearing modes as well as on the concepts for their control or avoidance.
Nanoradian angular stabilization of x-ray optical components
Authors: Stoupin Stanislav , Lenkszus Frank , Laird Robert , Goetze Kurt , Kim Kwang-Je , Shvyd’ko Yuri
Published: May 2010

An x-ray free-electron laser oscillator (XFELO) has been recently proposed [K. Kim et al., Phys. Rev. Lett. 100, 244802 (2008)]. Angular orientation and position in space of Bragg mirrors of the XFELO optical cavity must be continuously adjusted to compensate for the instabilities and maximize the output intensity. An angular stability of about 10 nrad (rms) is required [K. Kim and Y. Shvyd’ko, Phys. Rev. ST Accel. Beams 12, 030703 (2009)]. To approach this goal, a feedback loop based on a null-detection principle was designed and used for stabilization of a high-energy-resolution x-ray monochromator (ΔE/E≃4×10−8, E=23.7 keV) and a high-heat-load monochromator. Angular stability of about 13 nrad (rms) has been demonstrated for x-ray optical elements of the monochromators.
On vaporization in laser material interaction
Authors: Ki Hyungson
Published: May 2010

In this article, vaporization processes in the laser interaction with materials are studied theoretically and computationally, focusing on evaporation and homogeneous bubble nucleation. Simulations are carried out using the Redlich–Kwong equation of state and temperature-dependent material property models that can be used up to the critical point. From theoretical considerations, four important temperatures are identified in the understanding of laser material interaction. This study also shows that there are upper limits to the amount of energy that can be consumed by vaporization, which takes place at a temperature that is lower than the material’s critical point. This study also discusses the transition from the thermal mode of ablation to the nonthermal mode in terms of the energy capacity of homogeneous boiling.
A common-view disciplined oscillator
Authors: Lombardi Michael A. , Dahlen Aaron P.
Published: May 2010

This paper describes a common-view disciplined oscillator (CVDO) that locks to a reference time scale through the use of common-view global positioning system (GPS) satellite measurements. The CVDO employs a proportional-integral-derivative controller that obtains near real-time common-view GPS measurements from the internet and provides steering corrections to a local oscillator. A CVDO can be locked to any time scale that makes real-time common-view data available and can serve as a high-accuracy, self-calibrating frequency and time standard. Measurement results are presented where a CVDO is locked to UTC(NIST), the coordinated universal time scale maintained at the National Institute of Standards and Technology in Boulder, Colorado.
Study of a dual frequency atmospheric pressure corona plasma
Authors: Kim Dan Bee , Moon S. Y. , Jung H. , Gweon B. , Choe Wonho
Published: May 2010

Radio frequency mixing of 2 and 13.56 MHz was investigated by performing experimental measurements on the atmospheric pressure corona plasma. As a result of the dual frequency, length, current density, and electron excitation temperature of the plasma were increased, while the gas temperature was maintained at roughly the same level when compared to the respective single frequency plasmas. Moreover, observation of time-resolved images revealed that the dual frequency plasma has a discharge mode of 2 MHz positive streamer, 2 MHz negative glow, and 13.56 MHz continuous glow.
Manifestation of macroscopic correlations in elementary reaction kinetics. I. Irreversible reaction A+A→product
Authors: Doktorov Alexander B. , Kipriyanov Alexander A. , Kipriyanov Alexey A.
Published: May 2010

Using an modern many-particle method for the derivation of non-Markovian binary kinetic equations, we have treated theoretically the applicability of the encounter theory (ET) (the prototype of the collision theory) concepts to the widely known diffusion assisted irreversible bulk reaction A+A→product (for example, radical reaction) in dilute solutions. The method shows that the agreement with the ET is observed when the familiar integral ET is employed which in this method is just a step in the derivation of kinetic equations. It allows for two-particle correlations only, but fails to take account of correlation of reactant simultaneously with the partner of the encounter and the reactant in the bulk. However, the next step leading to the modified ET under transformation of equations to the regular form both extends the time range of the applicability of ET rate equation (as it was for reactions proceeding with one of the reactants in excess), and gives the equation of the generalized ET. In full agreement with physical considerations, this theory reveals macroscopic correlations induced by the encounters in the reservoir of free walks. This means that the encounters of reactants in solution are correlated on a rather large time interval of the reaction. Though any nonstationary (non-Markovian) effects manifest themselves rather weakly in the kinetics of the bimolecular reaction in question, just the existence of the revealed macroscopic correlations in the binary theory is of primary importance. In particular, it means that the well-known phenomena which are generally considered to be associated solely with correlation of particles on the encounter (for example, chemically induced dynamic nuclear polarization) may be induced by correlation in the reservoir of free random walks of radicals in solution.
Fully lithography independent fabrication of nanogap electrodes for lateral phase-change random access memory application
Authors: Zhang Jiayong , Wang Xiaofeng , Wang Xiaodong , Ma Huili , Cheng Kaifang , Fan Zhongchao , Li Yan , Ji An , Yang Fuhua
Published: May 2010

A nanogap electrode fabrication method was developed and nanogap electrode as small as 17 nm was achieved based on sacrificial spacer process and conventional lithography. We have transferred this method to lateral phase-change random access memory (PCRAM) device fabrication. The electrical characterizations of 4.6 μm gap width using conventional lithography and 88 nm width based on this technology are shown. It is found that the threshold voltage and the dc power consumption are remarkably decreased due to nanogap electrode process. Our method cannot only improve the fabrication efficiency of PCRAM but also be easily transferred to other nanoelectronics applications.
Silicon nanocrystals dispersed in water: Photosensitizers for molecular oxygen
Authors: Goller B. , Polisski S. , Wiggers H. , Kovalev D.
Published: May 2010

We report on the synthesis of freestanding silicon spheres having sizes in the range of 3–10 nm. As-prepared luminescent silicon nanocrystals have H-passivated surface. Therefore, energy transfer from excitons confined in Si nanocrystals to oxygen molecules is found to be efficient. It is demonstrated that a termination of silicon nanocrystal H-passivated hydrophobic surface by lipids provides their water solubility. We found that this procedure preserves photosensitizing ability of silicon nanocrystals. Therefore, this material system can potentially be employed for a variety of biomedical applications.
Efficient light management scheme for thin film silicon solar cells via transparent random nanostructures fabricated by nanoimprinting
Authors: Battaglia Corsin , Söderström Karin , Escarré Jordi , Haug Franz-Josef , Dominé Didier , Cuony Peter , Boccard Mathieu , Bugnon Grégory , Denizot Céline , Despeisse Matthieu , Feltrin Andrea , Ballif Christophe
Published: May 2010

We propose the use of transparent replicated random nanostructures fabricated via nanoimprinting on glass as next-generation superstrates for thin film silicon solar cells. We validate our approach by demonstrating short-circuit current densities for p-i-n hydrogenated microcrystalline silicon solar cells as high as for state-of-the-art nanotextured ZnO front electrodes. Our methodology opens exciting possibilities to integrate a large variety of nanostructures into p-i-n solar cells and allows to systematically investigate the influence of interface morphology on the optical and electronic properties of the device in order to further improve device performance.
Photoacoustic measurement of liquid viscosity
Authors: Lou Cunguang , Xing Da
Published: May 2010

In this letter, we report on the use of photoacoustic method to measure the viscosity of viscous liquids. The theoretical and experimental study was performed on the influence of viscosity effects on photoacoustic generation. We provide evidence that the frequency spectrum of photoacoustic signal is precisely related to the viscosity. Measurements are validated on different water–glycerol mixtures. Good agreement between theoretical and experimental results is obtained. This present method provides an insight into in situ viscosity measurements, which has potential for noninvasive detection of blood viscosity.
Low-lying spectra of massless Dirac electron in magnetic dot and ring
Authors: Lee C. M. , Lee Richard C. H. , Ruan W. Y. , Chou M. Y.
Published: May 2010

Both the size and the magnetic-field dependences of low-lying spectra of two-dimensional (2D) graphene based magnetic dot and ring in perpendicular inhomogeneous magnetic fields, where the magnetic field is zero inside the dot and ring, and constant elsewhere, are studied by the massless Dirac–Weyl equation. Numerical results obtained from direct diagonalization with 2D harmonic basis show that, under nonuniform magnetic fields, the higher Landau levels (N≥1) for such massless Dirac electron interacting system in general become nondegenerate and split into discrete angular momentum states with level crossings with the lowest one (N=0) being an exception.
Enhanced photoluminescence efficiency of mid-infrared InAsSb nanostructures using a carrier blocking layer
Authors: Lei W. , Tan H. H. , Jagadish C.
Published: May 2010

This paper presents a study on the emission efficiency enhancement of InAsSb nanostructures using a carrier blocking layer. InP is proposed to serve as the carrier blocking layer to suppress the thermal escape of carriers in InAsSb nanostructures and significantly enhance their emission efficiency at high temperature (good photoluminescence signal even at 330 K). However, this leads to a blueshift in their emission wavelength due to the significantly increased quantum confinement of the nanostructures. By inserting a thin InGaAs layer between InP blocking layer and InAsSb nanostructures, longer emission wavelength can be maintained. This provides an approach to achieve InAsSb nanostructures with both good high-temperature optical characteristics and long emission wavelength, which is very useful for fabricating mid-infrared emitters operating at room temperature.