bluuebunny/crossref_metadata_2025 huggingface dataset:
Modulation of Adipocyte Biology by Δ9‐Tetrahydrocannabinol
Authors: Teixeira Diana , Pestana Diogo , Faria Ana , Calhau Conceição , Azevedo Isabel , Monteiro Rosário
Published: May 2010

It is recognized that the endocannabinoid system (ECS) plays a crucial role in the modulation of food intake and other aspects of energy metabolism. In this study, we aimed to investigate the effects of Δ9‐tetrahydrocannabinol (THC) on adipocyte biology. 3T3–L1 cells were used to evaluate proliferation by sulforhodamine B (SRB) staining and methyl−3H‐thymidine incorporation after 48 or 72 h of treatment with THC (1–500 nmol/l). Cells were differentiated in the presence or absence of the cannabinoid, and adipogenesis was determined by measuring lipid accumulation and peroxisome proliferator‐activated receptor γ (PPARγ) transcription through reverse transcriptase‐PCR (RT‐PCR). Lipolysis was quantified under basal conditions or after isoproterenol (IP, 100 nmol/l) or insulin (INS, 100 nmol/l) treatment. Transforming growth factor β (TGFβ), diacylglycerol lipase α, andN‐acylphosphatidylethanolamine‐specific phospholipase D (NAPE‐PLD) transcriptions were determined by RT‐PCR in preadipocytes and adipocytes and adiponectin only in adipocytes. THC treatment increased culture protein content and reduced methyl−3H‐thymidine incorporation. Cells treated with THC underwent adipogenesis shown by the expression of PPARγ and had increased lipid accumulation. Basal and IP‐stimulated lipolyses were inhibited by THC and there was no effect on lipolysis of INS‐treated adipocytes. The effects on methyl−3H‐thymidine incorporation and lipolysis seem to be mediated through CB1‐ and CB2‐dependent pathways. THC decreased NAPE‐PLD in preadipocytes and increased adiponectin and TGFβ transcription in adipocytes. These results show that the ECS interferes with adipocyte biology and may contribute to adipose tissue (AT) remodeling. Although these observations point toward increased AT deposition, the stimulation of adiponectin production and inhibition of lipolysis may be in favor of improved INS sensitivity under cannabinoid influence.
Health‐Care Expenditures of Overweight and Obese Males and Females in the Medical Expenditures Panel Survey by Age Cohort
Authors: Bell Janice F. , Zimmerman Frederick J. , Arterburn David E. , Maciejewski Matthew L.
Published: May 2010

Age‐ and sex‐specific annual health‐care expenditures (total, in‐patient, ambulatory care, and outpatient prescription drug) were estimated within established weight classifications in a nationally representative sample of children and adults aged 6–85 years (n = 80,516) in the Medical Expenditures Panel Survey (MEPS). The expenditures were estimated with two‐part regression models and standard errors accounted for the complex survey design. Compared to their normal‐weight counterparts, total expenditures were higher for overweight females between age 22 ($85; 95% CI: $1, $166) and age 77 ($623; 95% CI: $14, $1,259); overweight males between age 48 ($168; 95% CI: $9, $312) and age 67 ($612; 95%: $31, $1,139); obese females between age 21 ($88; 95% CI: $12, $207) and age 82 ($1,497; 95% CI: $212, $2,592); and obese males between age 25 ($88; 95% CI: $9, $158) and age 83 ($3,236; 95% CI: $378, $6,637). Differences were primarily due to higher ambulatory care and prescription drug expenditures and, for women only, higher in‐patient expenditures. Overweight‐ and obesity‐associated health‐care expenditures are substantial and emerge at younger ages for women than for men. Expenditures associated with obesity exceed those associated with overweight. Further research is required to elucidate factors underlying the differences by sex.
Iron and Obesity in Females in the United States
Authors: Neymotin Florence , Sen Urmimala
Published: May 2010

Since the late 1980s, the United States has witnessed a dramatic increase in average BMI levels and the proportion of individuals categorized as obese. Obesity is a major risk factor for a variety of illnesses, and an increase in obesity is, therefore, implicated in increased health‐care costs in the United States. These ultimately translate to a major health and economic problem for the United States. The present analysis examines a pathway to increased levels of obesity as of yet almost entirely unexplored. Specifically, we examine the relationship between obesity and iron deficiency via analyses of blood samples. The current analysis employs public‐use data files from the continuous National Health and Nutrition Examination Survey (NHANES) (1999–2006) survey to determine the relationship between obesity and an individual's iron blood content. Results suggest a negative relationship between levels of iron blood content and individual BMI after controlling for other individual characteristics. These results hold for nearly all eight panels tested in the ordinary least squares (OLS) regressions.
Mechanisms, regulation and consequences of protein SUMOylation
Authors: Wilkinson Kevin A. , Henley Jeremy M.
Published: May 2010

The post-translational modification SUMOylation is a major regulator of protein function that plays an important role in a wide range of cellular processes. SUMOylation involves the covalent attachment of a member of the SUMO (small ubiquitin-like modifier) family of proteins to lysine residues in specific target proteins via an enzymatic cascade analogous to, but distinct from, the ubiquitination pathway. There are four SUMO paralogues and an increasing number of proteins are being identified as SUMO substrates. However, in many cases little is known about how SUMOylation of these targets is regulated. Compared with the ubiquitination pathway, relatively few components of the conjugation machinery have been described and the processes that specify individual SUMO paralogue conjugation to defined substrate proteins are an active area of research. In the present review, we briefly describe the SUMOylation pathway and present an overview of the recent findings that are beginning to identify some of the mechanisms that regulate protein SUMOylation.
Self-heating property under ac magnetic field and its evaluation by ac/dc hysteresis loops of NiFe2O4 nanoparticles
Authors: Kobayashi H. , Hirukawa A. , Tomitaka A. , Yamada T. , Jeun M. , Bae S. , Takemura Y.
Published: May 2010

The temperature rise of NiFe2O4 nanoparticles having diameters of 242 and 7.7 nm was measured. The results of the measurement were analyzed by comparing the areas of the hysteresis loops in order to clarify the mechanism of heat dissipation in the samples. The hysteresis loops were obtained by applying both ac and dc magnetic fields. It was found that the contribution of magnetic relaxation losses to the heat dissipation was negligible in the case of NiFe2O4 nanoparticle of diameter 242 nm. The contribution of the Néel relaxation to the heat dissipation in the case of NiFe2O4 nanoparticle of diameter 7.7 nm was observed as the difference between the areas of ac and dc hysteresis loops. From the dependences of temperature rise and hysteresis loops of the nanoparticles on the intensity and frequency of an applied magnetic field, the relaxation time for NiFe2O4 nanoparticle of diameter 7.7 nm was obtained as approximately 0.5–0.7 μs.
Study of magnetization reversal of uniaxial Ni nanodots by magnetic force microscopy and vibrating sample magnetometer
Authors: Ramaswamy Shivaraman , Rajan Ganesh K. , Gopalakrishnan C. , Ponnavaikko M.
Published: May 2010

In this work we report on the study of magnetization reversal in zero dimensional nickel nanodots patterned using a novel polymer based soft lithography technique. The nanodots, having their easy axis of magnetization normal to the plane of the sample, were characterized by in situ MFM observations, performed under varying magnetic fields to understand the magnetization reversal process. The average demagnetization curve of the sample was obtained from the MFM images. The results compare well with the demagnetization curve obtained from vibrating sample magnetometer (VSM) measurements. Further, the angular dependence of in-plane magnetization reversal process was investigated by studying the magnetization data obtained from the VSM performed at different angles of field orientation with respect to the sample.
Characterization of the magnetic properties of multilayer magnetostrictive iron-gallium nanowires
Authors: Park Jung Jin , Reddy Madhukar , Mudivarthi Chaitanya , Downey Patrick R. , Stadler Bethanie J. H. , Flatau Alison B.
Published: May 2010

We investigate the magnetic properties of magnetostrictive iron-gallium (Galfenol, Fe100−xGax, 10≤x≤25 at. %) nanowires with magnetic force microscopy (MFM) and using micromagnetic modeling software (magpar). Wires with diameters of 150 nm were fabricated in alternating multilayered structures with Fe-Ga and Cu having aspect ratios of ∼2 and ∼0.5, respectively, with the goal of minimizing the relative contribution of shape anisotropy to magnetic domain alignment. Micromagnetic simulations of isolated Fe-Ga segments with these dimensions predict that (1) at remanence, two opposing vortex structures will form at the ends of a Fe-Ga segment, with a single domain wall in the middle of the segment and (2) traditional magnetic dipoles will form at the ends of the segment to align with a large (saturation) external magnetic field. MFM results are presented that support these models. At remanence, no contrast is observed in the MFM phase images. Magnetic poles become evident at the ends of the Fe-Ga segments when a magnetic field exceeding ∼300 Oe is applied along the length of the nanowire. The direction of the pole alignment is readily flipped by changing the direction of applied field by 180°. Additionally, MFM images show rotation of the magnetic poles in each Fe-Ga segment as they align with fields of ∼550 Oe applied at angles of ∼55° and ∼105° relative to the length of the nanowire. The MFM results support the simulation results and demonstrate that an aspect ratio of ∼2 will reduce shape anisotropy effects sufficiently in Fe-Ga nanowire that magnetization can lie off of the nanowire axis.
Multiferroic double perovskites: Opportunities, issues, and challenges
Authors: Singh M. P. , Truong K. D. , Jandl S. , Fournier P.
Published: May 2010

A well-controlled coupled behavior in magnetoelectric materials at room temperature remains challenging. We demonstrate that the self-ordered A2B′B″O6 (e.g., A=La, B′=Mn, and B″=Ni) double perovskites provide a unique alternative opportunity to control and/or to induce such behavior in oxides. Herein, we outline and discuss the various challenges and bottleneck issues related to this class of materials.
Synthesis and magnetic properties of iron sulfide nanosheets with a NiAs-like structure
Authors: Lin Chun-Rong , Lu Shin-Zong , Lyubutin Igor S. , Korzhetskiy Yu V. , Wang Sheng-Chang , Suzdalev Igor P.
Published: May 2010

We have synthesized the hexagonal pyrrhotite Fe1−xS nanodisks with the NiAs-type structure via thermal decomposition of ferrous chloride and thiourea in oleylamine. Mössbauer spectra analysis shows that the main part of iron of hexagonal pyrrhotite is in the Fe2+ valence state, and the spectrum has broadened half-maximum width due to the vacancy distribution. Magnetic measurements indicate that the magnetic moment configuration of nanodisks transforms from the ferrimagnetic to the ferromagnetic state at 400 K and magnetic moment disordering takes place at the Curie temperature, 580 K, at which ferromagnetic state transforms to paramagnetic structure. This magnetic transition behavior can be explained in terms of the iron vacancy rearrangement.
The director and molecular dynamics of the field-induced alignment of a Gay–Berne nematic phase: An isothermal-isobaric nonequilibrium molecular dynamics simulation study
Authors: Luckhurst Geoffrey R. , Satoh Katsuhiko
Published: May 2010

Isothermal-isobaric molecular dynamics simulations have been performed for the generic Gay–Berne (GB) mesogen, GB(4.4, 20.0, 1, 1), to investigate director and molecular rotational motion during the field-induced alignment of a nematic. The alignment process for the director is discussed within the context of a hydrodynamic analysis based on the Ericksen–Leslie theory and this is found to predict the simulated behavior well. The dependence of the relaxation time for the alignment on the field strength is also in good accord with the theory. The rotational viscosity coefficient estimated from the simulation is smaller than that typically observed for real nematics and the possible reasons for this are discussed. However, the simulation results are found to follow not only the theory but also the experiments, at least qualitatively. No significant variation in the local and long-range structure of the nematic phase is found during the field-induced alignment process. In addition, we have explored the molecular dynamics in the nematic phase in the presence of the field using the first- and second-rank time autocorrelation functions. More importantly we are able to show that the director relaxation time is longer than that for molecular rotation. It is also possible to use the two orientational correlation times to explore the relationship between the rotational viscosity coefficient and the rotational diffusion constant. The diffusion constants determined from the orientational correlation times, based on the short-time expansion of the autocorrelation functions, are found to be significantly different. In consequence it is not possible to test, unambiguously, the relationship between the rotational viscosity coefficient and the rotational diffusion constant. However, it would seem that the second-rank rotational correlation time provides the most reliable route to the rotational viscosity coefficient.
A note on wave equation in Einstein and de Sitter space-time
Authors: Galstian Anahit , Kinoshita Tamotu , Yagdjian Karen
Published: May 2010

We consider the wave propagating in the Einstein and de Sitter space-time. The covariant d’Alembert’s operator in the Einstein and de Sitter space-time belongs to the family of the non-Fuchsian partial differential operators. We introduce the initial value problem for this equation and give the explicit representation formulas for the solutions. We also show the Lp−Lq estimates for solutions.
Evaluation of bimaterial cantilever beam for heat sensing at atmospheric pressure
Authors: Toda Masaya , Ono Takahito , Liu Fei , Voiculescu Ioana
Published: May 2010

The bimaterial cantilever beam is an important basic structure of microelectromechanical system thermal devices. The research described in this paper is a study of the deflection of the bimaterial cantilever beam operated in the air and irradiated with a laser beam at the free end. The bimaterial cantilever beam is a composite structure formed by layers of silicon nitride and gold. The temperature variations produce the deflection of the cantilever beam end due to different values of the thermal expansion coefficients of silicon nitride and gold. The deflection was experimentally measured in vacuum and atmospheric pressure when a laser beam was irradiated at the free end. A formula for the calculation of the deflection as a function of incident power applied at the free end of the cantilever beam operated in air was also demonstrated. The predicted values of the deflection calculated using this formula and the experimental values of the deflection were compared, and the results were in good agreement. A systematic investigation of the cantilever beam deflection in vacuum and atmospheric pressure as a function of the heat applied at the free end is important for chemical and biological applications.
Realizations of conformal current-type Lie algebras
Authors: Pei Yufeng , Bai Chengming
Published: May 2010

In this paper we obtain the realizations of some infinite-dimensional Lie algebras, named “conformal current-type Lie algebras,” in terms of a two-dimensional Novikov algebra and its deformations. Furthermore, Ovsienko and Roger’s loop cotangent Virasoro algebra, which can be regarded as a nice generalization of the Virasoro algebra with two space variables, is naturally realized as an affinization of the tensor product of a deformation of the two-dimensional Novikov algebra and the Laurent polynomial algebra. These realizations shed new light on various aspects of the structure and representation theory of the corresponding infinite-dimensional Lie algebras.
Spinor algebra and null solutions of the wave equation
Authors: Wehbe Mohammad
Published: May 2010

In this paper we exploit the ideas and formalisms of twistor theory, to show how, on Minkowski space, given a null solution of the wave equation, there are precisely two null directions in ker df, at least one of which is a shear-free ray congruence.
Linear and nonlinear theories of a large-orbit gyrotron traveling wave amplifier
Authors: Jiao Chongqing , Luo Jirun
Published: May 2010

The linear and nonlinear theories of large-orbit gyrotron traveling wave amplifiers (gyro-TWAs) have been developed based on the corresponding theories of small-orbit gyro-TWAs. The linear theory is in good agreement with the nonlinear theory in the small signal region of large-orbit gyro-TWAs. The phenomenon that most electrons move toward the axis of interaction circuit during the beam-wave interaction is observed and its potential effect on the design of large-orbit coaxial gyro-TWAs is emphasized.
The periodic b-equation and Euler equations on the circle
Authors: Escher Joachim , Seiler Jörg
Published: May 2010

In this note we show that the periodic b-equation can only be realized as a Euler equation on the Lie group Diff∞(S1) of all smooth and orientation preserving diffeomorphisms on the circle if b=2, i.e., for the Camassa–Holm equation. In this case the inertia operator generating the metric on Diff∞(S1) is given by A=1−∂x2. In contrast, the Degasperis–Procesi equation, for which b=3, is not a Euler equation on Diff∞(S1) for any inertia operator. Our result generalizes a recent result of Kolev [“Some geometric investigations on the Degasperis-Procesi shallow water equation,” Wave Motion 46, 412–419 (2009)].
Study of the relaxational and vibrational dynamics of bioprotectant glass-forming mixtures by neutron scattering and molecular dynamics simulation
Authors: Magazù S. , Migliardo F. , Affouard F. , Descamps M. , Telling M. T. F.
Published: May 2010

In this work inelastic neutron scattering (INS) and quasielastic neutron scattering (QENS) data, collected at different temperature values by the OSIRIS and IRIS spectrometers at the ISIS Facility (Rutherford Appleton Laboratory, Oxford, UK) on mixtures of two glass-forming bioprotectant systems, i.e., trehalose and glycerol, as a function of concentration are presented. The data analyses show that the fast local dynamics, measured by INS, as well as the diffusive dynamics, measured by QENS, exhibit in the investigated mixtures a switching-off maximum in the same concentration range corresponding to a very low glycerol content. This effect can be accounted for by a not-ideal mixing process of the pure constituents due to an increased hydrogen bonding network strength. The experimental studies are completed by molecular dynamics simulation findings.
Statistical average of model orbital potentials for extended systems: Calculation of the optical absorption spectrum of liquid water
Authors: Bernasconi Leonardo
Published: May 2010

Time-dependent density functional theory (TD-DFT) calculations of the electronic response of molecular and bulk liquid water based on a very accurate orbital-dependent ground-state exchange-correlation potential, the statistical average of (model) orbital potentials (SAOP), and on the adiabatic local density approximation (ALDA) for the exchange-correlation kernel are described. The quality of the calculated excitation energies, both in the molecule and in the liquid, is assessed by comparison to hybrid TD-DFT calculations and experimental data. A combination of classical molecular dynamics simulations and TD-DFT calculations sampling several disordered configurations of a small liquid sample is then used to simulate the optical absorption spectrum in the region of 0–15 eV. The resulting room-temperature absorption profile is discussed in connection with previous TD-DFT calculations as well as with results from Green’s function theory and experiment.
Magnetohydrodynamic analysis of the interaction of magnetized plasma flow with a perfect-conducting object
Authors: Nishida Hiroyuki , Abe Takashi
Published: May 2010

In this study, a supersonic and super-Alfvénic magnetized plasma flow past a perfect-conducting cylinder was simulated based on single-fluid ideal magnetohydrodynamics to clarify the piling-up process of the magnetic field frozen in the plasma flow. Therefore, the magnetic field is assumed to be perpendicular to both the cylinder axis and the flow direction. Simulation results indicated that the cylinder continuously traps the magnetic field and an unsteady flow field is generated. Even though the drag force exerting on the cylinder is expected to continuously increase with the continuous increase in the trapped magnetic field and the shock layer, the intensity of magnetic flux density at the cylinder surface is saturated at a certain value and the drag force is also saturated. The saturated values are characterized by the Alfvén Mach number of the mainstream. Furthermore, on this flow structure the wake flow in which magnetic reconnection plays an important role was found to have a strong influence by using the pseudomagnetic reconnection in the ideal magnetohydrodynamic flow.
A numerical matching technique for linear resistive magnetohydrodynamics modes
Authors: Furukawa M. , Tokuda S. , Zheng L.-J.
Published: May 2010

A new numerical matching technique for linear stability analysis of resistive magnetohydrodynamics (MHD) modes is developed. The solution to the resistive reduced MHD equations in an inner layer with a finite width is matched onto the solution to the inertialess ideal MHD or the Newcomb equation by imposing smooth disappearance of parallel electric field in addition to the continuity of perturbed magnetic field and its spatial gradient. The boundary condition for the parallel electric field is expressed as a boundary condition of the third kind for the stream function of the perturbed velocity field. This technique can be applied for the reversed magnetic shear plasmas of their minimum safety factors being rational numbers, for which the conventional asymptotic matching technique fails. In addition, this technique resolves practical difficulties in applying the conventional asymptotic matching technique, i.e., the sensitivity of the outer-region solution on the accuracy of the local equilibrium as well as the grid arrangements, even in normal magnetic shear plasmas. Successful applications are presented not only for the eigenvalue problem but also for the initial-value problem.
Nanoscale range finding of subsurface structures by measuring the absolute phase lag of thermal wave
Authors: Chung Jaehun , Kim Kyeongtae , Hwang Gwangseok , Kwon Ohmyoung , Lee Joon Sik , Park Seung Ho , Choi Young Ki
Published: May 2010

The need for a subsurface imaging technique to locate and characterize subsurface defects in multidimensional micro- and nanoengineered devices has been growing rapidly. We show that a subsurface heater can be located accurately using the phase lag of a thermal wave. We deduce that the absolute phase lag is composed of four components. Among the four components, we isolate the component directly related to the position and the structure of the periodic heat source. We demonstrate that the position of the heater can be estimated accurately from the isolated phase lag component.
Accuracy of perturbation theory for nonadiabatic effects in adsorbate-surface dynamics
Authors: Mizielinski M. S. , Bird D. M.
Published: May 2010

An independent-electron formalism is developed to describe the energetic distributions of hot electrons and holes excited in the interaction between an adsorbate and a metal surface. The formalism encompasses both a fully nonadiabatic treatment and a perturbation expansion in the adsorbate velocity that can be taken to arbitrary order. The widely used electronic friction and forced oscillator models are shown to be approximations of the second order perturbation result. A simple tight binding model of an atomic adsorbate interacting with a metal surface is used to demonstrate the formalism. It is shown that many orders (>10) of perturbation theory are required for quantitative agreement with fully nonadiabatic calculations of the electron and hole distribution functions. However, lower order approximations can provide a useful, semiquantitative picture of the distribution functions, and they are in good agreement with nonperturbative results for the total rate of nonadiabatic energy dissipation.
Two-dimensional graphene superlattice made with partial hydrogenation
Authors: Yang Ming , Nurbawono Argo , Zhang Chun , Feng Yuan Ping , Ariando
Published: May 2010

Electronic properties of two-dimensional 2D graphene superlattice made with partial hydrogenation were thoroughly studied via density functional tight binding approach which incorporates the tight-binding method into the density functional formalism. The 2D pattern of hydrogen atoms on graphene was found to have great effects on electronic structures of graphene superlattice. In particular, the edges of the 2D pattern, armchair or zigzag, are essential for the energy band gap opening, and the energy band gap sensitively depends on the shape, size, and the 2D periodicity of the pattern. Based on these findings, we suggested that the 2D graphene superlattice could be used in fabricating graphene quantum dots or heterojunctions without the need for cutting or etching.
Optical and microstructural properties versus indium content in InxGa1−xN films grown by metal organic chemical vapor deposition
Authors: Gokarna A. , Gauthier-Brun A. , Liu W. , Androussi Y. , Dumont E. , Dogheche E. , Teng J. H. , Chua S. J. , Decoster D.
Published: May 2010

We present comparative investigations of single phase InxGa1−xN alloys for a varying In content (x=0.07 to 0.14) grown by metal organic chemical vapor deposition (MOCVD) technique. While the composition was determined using secondary ion mass spectroscopy, we have investigated the microstructures in InxGa1−xN/GaN films by using transmission electron microscopy and correlated these with the refractive index of the material. Based on ellipsometric analysis of the films, the dispersion of optical indices for InxGa1−xN films is determined by using Tauc–Lorentz dispersion equations.
Transformation between dense and sparse spirals in symmetrical bistable media
Authors: He Ya-Feng , Ai Bao-Quan , Hu Bambi
Published: May 2010

Transformation between dense and sparse spirals is studied numerically based on a bistable FitzHugh–Nagumo model. It is found that the dense spiral can transform into two types of sparse spirals via a subcritical bifurcation: positive phase sparse spiral and negative phase sparse spiral. The choice of the two types of sparse spirals after the transformation is affected remarkably by the boundary effect if a small domain size is applied. Moreover, the boundary effect gives rise to novel meandering of sparse spiral with only outward petals.
New ambient pressure photoemission endstation at Advanced Light Source beamline 9.3.2
Authors: Grass Michael E. , Karlsson Patrik G. , Aksoy Funda , Lundqvist Måns , Wannberg Björn , Mun Bongjin S. , Hussain Zahid , Liu Zhi
Published: May 2010

During the past decade, the application of ambient pressure photoemission spectroscopy (APPES) has been recognized as an important in situ tool to study environmental and materials science, energy related science, and many other fields. Several APPES endstations are currently under planning or development at the USA and international light sources, which will lead to a rapid expansion of this technique. The present work describes the design and performance of a new APPES instrument at the Advanced Light Source beamline 9.3.2 at Lawrence Berkeley National Laboratory. This new instrument, Scienta R4000 HiPP, is a result of collaboration between Advanced Light Source and its industrial partner VG-Scienta. The R4000 HiPP provides superior electron transmission as well as spectromicroscopy modes with 16 μm spatial resolution in one dimension and angle-resolved modes with simulated 0.5° angular resolution at 24° acceptance. Under maximum transmission mode, the electron detection efficiency is more than an order of magnitude better than the previous endstation at beamline 9.3.2. Herein we describe the design and performance of the system, which has been utilized to record spectra above 2 mbar.
Asymptotic regularity for p-Laplacian equation
Authors: Liu Yuewei , Yang Lu , Zhong Chengkui
Published: May 2010

This paper is devoted to proving some asymptotic regularity of the solutions of the p-Laplacian equation ut−div(|∇u|p−2∇u)+f(u)=g(x) (p∊(2,N)) considered on a bounded domain Ω⊂RN(N≥3). The nonlinear term f satisfies the polynomial growth condition of arbitrary order c1|u|q−k≤f(u)u≤c2|u|q+k, where q≥2 is arbitrary. As an application of the asymptotic regularity results, we not only can obtain the existence of a (L2(Ω),W01,p(Ω)∩Lq(Ω))-global attractor A immediately but also can show further that A attracts every bounded subsets of L2(Ω) under the W01,p∩Lq+δ-norm for any δ∊[0,∞). Furthermore, the fractal dimension of A is finite in Lq+δ(Ω) for any δ∊[0,∞).
High rate concentration measurement of molecular gas mixtures using a spatial detection technique
Authors: Loriot V. , Hertz E. , Lavorel B. , Faucher O.
Published: May 2010

Concentration measurement in molecular gas mixtures using a snapshot spatial imaging technique is reported. The approach consists of measuring the birefringence of the molecular sample when field-free alignment takes place, each molecular component producing a signal with an amplitude depending on the molecular density. The concentration measurement is obtained on a single-shot basis by probing the time-varying birefringence through femtosecond time-resolved optical polarigraphy (FTOP). The relevance of the method is assessed in air.
A model for underpotential deposition in the presence of anions
Authors: Giménez M. C. , Ramirez-Pastor A. J. , Leiva E. P. M.
Published: May 2010

A simple model to study the effect of on top coadsorption of anions in underpotential deposition is formulated. It considers a lattice-gas model with pair potential interactions between nearest neighbors. As test system, the electrodeposition of silver on gold is studied by means of grand canonical Monte Carlo simulations. The influence of anions on the adsorption isotherms is analyzed. It is found that as the interaction between silver atoms and anions increases, the monolayer adsorbs at more negative chemical potentials. For large interactions between silver atoms and anions, a expanded structure occurs for the silver monolayer.
Electric energy storage properties of poly(vinylidene fluoride)
Authors: Li Wenjing , Meng Qingjie , Zheng Yuansuo , Zhang Zhicheng , Xia Weimin , Xu Zhuo
Published: May 2010

High discharged energy density observed in poly(vinylidene fluoride) (PVDF) based copolymers has attracted considerable research interests in the past years. Crystalline properties exhibit great influence on their dielectric and energy storage properties. To understand how crystalline properties influence the energy storage properties of PVDF, PVDF films with three different crystal forms are investigated in this paper. It is shown that γ-PVDF is allowed to work under higher electric fields than α- and β-PVDF in the absence of phase transition in α-PVDF and early polarization saturation in β-PVDF. Consequently, γ-PVDF exhibits the highest energy density of 14 J/cm3 under 500 MV/m electric field.
Three-dimensional surface current loops in terahertz responsive microarrays
Authors: Randhawa Jatinder S. , Gurbani Saumya S. , Keung Michael D. , Demers Devin P. , Leahy-Hoppa Megan R. , Gracias David H.
Published: May 2010

We investigated the effect of the third dimension in terahertz (THz) responsive microarrays using finite element simulations and by measuring their transmission spectra in the range of 0.2 to 1.1 THz. We observed that the presence of three-dimensional (3D) surface current loops in microarrays composed of cubic units resulted in enhanced transmission as compared to two-dimensional single and stacked layers, suggesting that the incorporation of geometries that enable truly 3D current loops is an important factor in optically responsive metamaterials.
Acoustic electromechanical energy loss mechanism for suspended micro- and nanoelectromechanical resonators
Authors: Gusso André
Published: May 2010

An acoustic electromechanical energy loss mechanism, relevant for suspended micro- and nanoelectromechanical resonators, is investigated theoretically. The energy loss results from the conversion of the mechanical energy from the vibration of the resonator into acoustic waves due to the coupling between the resonator and nearby structures resulting from electrostatic forces caused by the applied voltage bias. Analytical expressions are derived for the quality factor of cantilever and bridge resonators in close proximity to an underlying substrate. By comparison with experimental results it is concluded that such mechanism can be a dominant source of dissipation for practical devices.
Physical and chemical characterization of combinatorial metal gate electrode Ta–C–N library film
Authors: Chang K.-S. , Green M. L. , Levin I. , Hattrick-Simpers J. R. , Jaye C. , Fischer D. A. , Takeuchi I. , De Gendt S.
Published: May 2010

This paper reports comprehensive structural and chemical analyses for the combinatorial Ta–C–N/HfO2 system, crucial data for understanding the electrical properties of Ta–C–N/HfO2. Combinatorial Ta–C–N “library” (composition spread) films were deposited by magnetron sputtering. Electron probe wavelength dispersive spectroscopy and x-ray fluorescence-yield near-edge spectroscopy were used to quantitatively determine the composition across these films. Scanning x-ray microdiffractometry determined that a solid solution of Ta(C,N)x forms and extends to compositions (0.3≤Ta≤0.5 and 0.57≤Ta≤0.67) that were previously unknown. The thermal stability of the Ta–C–N/HfO2 library was studied using high resolution transmission electron microscopy, which shows Ta–C–N/HfO2/SiO2/Si exhibiting good thermal stability up to 950 °C.
A Fabry–Pérot electro-optic sensing system using a drive-current-tuned wavelength laser diode
Authors: Kuo Wen-Kai , Wu Pei-Yu , Lee Chang-Ching
Published: May 2010

A Fabry–Pérot enhanced electro-optic sensing system that utilizes a drive-current-tuned wavelength laser diode is presented. An electro-optic prober made of LiNbO3 crystal with an asymmetric Fabry–Pérot cavity is used in this system. To lock the wavelength of the laser diode at resonant condition, a closed-loop power control scheme is proposed. Experiment results show that the system can keep the electro-optic prober at high sensitivity for a long working time when the closed-loop control function is on. If this function is off, the sensitivity may be fluctuated and only one-third of the best level in the worst case.
Spin-filtering transport and switching effect of MnCu single-molecule magnet
Authors: Hao H. , Zheng X. H. , Dai Z. X. , Zeng Z.
Published: May 2010

Electron transport of a single-molecule magnet (SMM) device has been investigated using the first-principles calculations. The SMM based device is constructed by a SMM MnCu [MnCuCl(5-Br-sap)2(MeOH)] bridged between semi-infinite Au(100) electrodes with thiol groups connecting the molecule and the gold electrodes. Our results exhibit crucial features of spin filtering and Kondo resonance. The spin filtering remains robust, whereas the Kondo resonance highly depends on the contact geometry. Specifically, this Kondo resonance can be switched on or off by changing the contact distance. The mechanisms of these features are formulated in details.
Transversal electrostatic strength of patterned collector affecting alignment of electrospun nanofibers
Authors: Pokorny Marek , Niedoba Krzysztof , Velebny Vladimir
Published: May 2010

Conventional electrospinning produces randomly ordered nanofibers, however many potential applications require precisely defined morphology and anisotropic properties of nanofibrous materials. In this work, a collector consisting of two segments has been used to prepare uniaxially ordered nanofibers. Optimized collector design comes from both analytical calculations of electrostatic strength in the vicinity of the electrodes and from experimental verification by polyvinyl alcohol nanofibers fabrication. The transversal electric strength is a key factor in achieving very well aligned nanofibers. The results presented here help provide a better understanding of the electrically induced alignment mechanism.
Ferrofluid dynamics, magnetic relaxation, and irreversible thermodynamics
Authors: Felderhof B. U. , Sokolov V. V. , Éminov P. A.
Published: May 2010

The dynamics of ferrofluids is discussed on the basis of Maxwell’s equations and the balance equations for mass, momentum, angular momentum, and energy. It is shown that the requirement of irreversible thermodynamics that the local rate of entropy production be positive definite allows equations of motion, and a corresponding magnetic relaxation equation, characterized by three convective parameters.
Photoluminescence studies of high-quality InAlN layer lattice-matched to GaN grown by metal organic chemical vapor deposition
Authors: Chen Z. T. , Sakai Y. , Egawa T.
Published: May 2010

Temperature-dependent photoluminescence (PL) measurements have been performed on high-quality InAlN layers lattice-matched (LM) to GaN with different thicknesses. It is found that the PL is consisted of two components denoted as IH (high-energy side) and IL (low-energy side), respectively. IH is attributed to exciton luminescence of bulk InAlN with linewidth comparable to those calculated under the assumption of perfect random alloy. While IL is attributed to the emission from the quantum-dotlike structure on the surface of InAlN, revealing the importance of surface effect to the investigations related to InAlN LM to GaN.
Model Boosting for Spatial Weighting Matrix Selection in Spatial Lag Models
Authors: Kostov Philip
Published: May 2010

The spatial lag specification is often used in spatial econometrics. The choice of an appropriate spatial weighting matrix is an important outstanding methodological problem in the quantitative spatial dependence literature. This paper proposes applying a component-wise model-boosting algorithm to deal with the issue of the choice of a spatial weighting matrix amongst a predetermined set of alternatives. The resulting procedure is computationally simple and easy to implement. I present an empirical application of the proposed methodology. Some possible extensions to a more general setting are discussed.
Sex and sport: sexual risk behaviour in young people in rural and regional Victoria
Authors: Kong Fabian Y. S. , Hocking Jane S. , Link Chris Kyle , Chen Marcus Y. , Hellard Margaret E.
Published: May 2010

Background: To determine the prevalence of chlamydia and understand sexual risk behaviour in 16–29 year olds in rural Victoria through a chlamydia testing program undertaken at local sporting clubs. Methods: Young people were recruited from the Loddon Mallee region of Victoria, Australia between May and September 2007. After a night of sporting practice, participants provided a first pass urine sample and completed a brief questionnaire about sexual risk behaviour. Those positive for chlamydia were managed by telephone consultation with a practitioner from Melbourne Sexual Health Centre. Results: A total of 709 young people participated (77% male, 23% female) in the study; 77% were sexually active. Overall chlamydia prevalence in sexually active participants was 5.1% (95% confidence interval [CI]: 3.4–7.3); 7.4% in females (95% CI: 3.5–13.6) and 4.5% in males (95% CI: 2.7–6.9). Approximately 60% of males and 20% of females consumed alcohol at high ‘Risky Single Occasion Drinking’ levels at least weekly and 60% had used an illicit drug in their lifetime. Nearly 45% reported having sex in the past year when they usually wouldn’t have because they were too drunk or high. Sexually transmissible infection (STI) knowledge was generally poor and only 25% used a condom the last time they had sex. Conclusion: Chlamydia prevalence was high in our study population. Many participants had poor knowledge about STIs and low condom use. These findings combined with high levels of risky alcohol use and having sex while intoxicated highlights the need for programs in rural and regional Victoria that combine both STI testing and prevention and education programs.
African Australians living with HIV: a case series from Victoria
Authors: Lemoh Chris N. , Baho Samia , Grierson Jeffrey , Hellard Margaret , Street Alan , Biggs Beverley-Ann
Published: May 2010

Background: This research aimed to describe the characteristics of African-born Victorians living with HIV, identify associations with delayed HIV diagnosis and describe their response to combination antiretroviral therapy (cART). Methods: A case series of African-born adults living with HIV in Victoria was conducted. Data was collected in interviews and reviews of case notes. Associations with delayed HIV diagnosis (CD4 below 200 cells µL–1 at diagnosis and/or AIDS within 3 months of HIV diagnosis) were explored using univariate regression. AIDS-defining illnesses and response to cART were described. Results: Fourteen males and six females were included. Ten were born in the Horn of Africa (nine in Ethiopia). Sixteen had sexual exposure (12 heterosexual; four male-to-male sex). Seven reported acquiring HIV in Australia. Median CD4 count at diagnosis was 145 cells µL–1. Ten had delayed HIV diagnosis, of whom eight were born in the Horn of Africa. Delayed HIV diagnosis was associated with birth in the Horn of Africa (odds ratio: 11.56). Nine had a diagnosis of AIDS, including three cases of tuberculosis, three of Pneumocystis jiroveci pneumonia and two of cerebral toxoplasmosis. Eighteen had received cART, of which 16 achieved virological suppression and 15 achieved a CD4 count above 200 cells µL–1. Clinical failure and virological failure occurred in seven and five cases, respectively. Conclusions: HIV prevention strategies for Victoria’s African communities should address HIV exposure in Australia. Ethiopian-born Victorians with HIV appear to be at particular risk of delayed diagnosis. Response to cART in this series was comparable to that observed in other industrialised countries.
Sexual practices and dental dam use among women prisoners - a mixed methods study
Authors: Yap Lorraine , Richters Juliet , Butler Tony , Schneider Karen , Kirkwood Kristie , Donovan Basil
Published: May 2010

Background: Dental dams have been distributed to women prisoners for protection against HIV and other sexually transmissible infections (STIs) in some Canadian and Australian prisons for over a decade. However, we do not know whether they serve any useful public health purpose. Objective: To determine how dental dams are used in women’s prisons in New South Wales (NSW), Australia. Method: Using quantitative and qualitative methods, we investigated women’s sexual practices with a focus on how dental dams are used in NSW prisons. Results: Although 71 of the 199 (36%) women reported having had sex with another inmate, with oral sex involved in most encounters, only eight (4%) had ever used a dental dam. The main sources of STI transmission risk among women prisoners were oral sex, manual sex and sharing dildos. Furthermore, sharing razors could also allow the transmission of blood-borne viruses, which could occur during sex in the presence of cuts or menstrual fluid. The high rates of hepatitis B and C among incarcerated women compound this risk. Conclusion: Dental dams are not widely used by women prisoners and we question their utility in women’s prisons. Oral sex is an important risk factor for acquisition of herpes simplex virus type 1, but most women in NSW prisons (89%) are already infected. Condoms and latex gloves may have more use. Condoms could be used as a barrier on shared dildos and sex toys, while latex gloves could be used to protect cut and grazed hands from vaginal and menstrual fluids.
Australian grassland fire danger using inputs from the GRAZPLAN grassland simulation model
Authors: Gill A. Malcolm , King Karen J. , Moore Andrew D.
Published: May 2010

Assessing and broadcasting the Fire Danger Rating each day of the fire season is an important activity in fire-prone nations. For grasslands in Australia, grass curing and biomass are biological variables that are not usually archived yet as inputs, along with weather data, to the calculation of Grassland Fire Danger Index (GFDI) and potential fire intensity. To assess past changes in the index, the biological inputs for GFDI for Canberra in south-eastern Australia were obtained using a pasture simulator, GRAZPLAN. Shoot biomass (including leaf litter) and grass curing were modelled using three contrasting pasture models (exotic annual, exotic perennial and native perennial) in order to calculate two variants of McArthur’s GFDI Mark 4 (the original and a modified version which includes fuel load); values were either capped at 100 as in the original (the ‘worst possible’ condition) or left open-ended. GFDI, and the potential fire intensity for fires burning with the wind each afternoon during a 54-year period were calculated. The native perennial grass model gave contrasting results to those from the exotic perennial grass model, whereas the annual grass model usually was intermediate in behaviour. GRAZPLAN outputs allow not only retrospective examination, but also provide a basis for predicting potential fire danger and behaviour as a result of climate change.
A model for predicting human-caused wildfire occurrence in the region of Madrid, Spain
Authors: Vilar Lara , Woolford Douglas. G. , Martell David L. , Martín M. Pilar
Published: May 2010

This paper describes the development and validation of a spatio-temporal model for human-caused wildfire occurrence prediction at a regional scale. The study area is the 8028-km2 region of Madrid, located in central Spain, where more than 90% of wildfires are caused by humans. We construct a logistic generalised additive model to estimate daily fire ignition risk at a 1-km2 grid spatial resolution. Spatially referenced socioeconomic and weather variables appear as covariates in the model. Spatial and temporal effects are also included. The variables in the model were selected using an iterative approach, which we describe. We use the model to predict the expected number of fires in our study area during the 2002–05 period, by aggregating the estimated probabilities over space–time scales of interest. The estimated partial effects of the presence of railways, roads, and wildland–urban interface in forest areas were highly significant, as were the observed daily maximum temperature and precipitation.