bluuebunny/crossref_metadata_2025_split huggingface dataset:
Ultrasonic‐electrodeposition of Flower‐like Graphene Nanosheets in Ionic Liquid and Its Sensing for Ascorbic Acid
Authors: Sheng Qinglin , He Yaping , Zhang Dawei , Zheng Jianbin 
Published: November 2012

AbstractCholine chloride–based ionic liquid Ethaline were employed as the supporting electrolyte, graphene (GE) nanosheet was prepared with ultrasonic wave assisted electrodeposition for the first time. Scanning electron microscope results indicated that flower‐like GE nanosheets were obtained at the electrode surface. Energy dispersive X–ray spectroscopy, Fourier transform infrared spectra and Raman spectra were used to characterize the composition of the flower‐like GE nanosheets. Electrochemical methods showed that the flower‐like GE nanosheets based sensor exhibited high electrocatalytic activity for ascorbic acid (AA) oxidation and can be potentially used for the sensitive amperometric sensing of AA. Amperometric experiments showed that the sensor displayed broad linearity from 0.25 μM to 2.0 mM with a relative low detection limit of 0.1 μM (S/N = 3).
Selective catalytic reduction of NOx with NH3 over iron–cerium mixed oxide catalyst: catalytic performance and characterization
Authors: Zhibo Xiong , Chunmei Lu , Dongxu Guo , Xinli Zhang , Kuihua Han 
Published: November 2012

AbstractBACKGROUNDSelective catalytic reduction (SCR) of NO with NH3 has been proved to reduce nitric oxides in exhaust flue gas from coal‐fired power plants. The commercial V2O5 ‐WO3 (MoO3)/TiO2 catalyst has the disadvantages of high reaction temperature (573–673 K), high conversion of SO2 to SO3 and toxicity of vanadium pent‐oxide to the environment and human health. Therefore, it is of some urgency to develop SCR catalyst, which works effectively in medium and low temperature ranges. In this study, a series of cerium–iron mixed oxide catalyst were prepared through a co‐precipitation method and showed strong low‐temperature SCR activity.RESULTSThe SCR activity over iron oxide was improved significantly by adding a small amount of cerium, especially the low‐temperature activity. Cerium sharply increased the BET surface area and the pore volume of iron oxide, and also enhanced its oxidation activity of NO to NO2. The NOx conversion was improved when partial NO2 was introduced into the flue gas. Iron oxide in catalyst was amorphous phase after adding a small amount of cerium.CONCLUSIONThe SCR activity over iron oxide was improved by substituting partial Fe with Ce, and the optimized conditions for SCR with iron–cerium mixed oxide catalyst were validated in this study.© 2012 Society of Chemical Industry
A New Insight Into the Mechanism of the Ring‐Opening Polymerization of Trimethylene Carbonate Catalyzed by Methanesulfonic Acid
Authors: Campos João M. , Ribeiro Maria R. , Ribeiro Maria F. , Deffieux Alain , Peruch Frédéric 
Published: November 2012

AbstractThe ring‐opening polymerization (ROP) of trimethylene carbonate (TMC) initiated by a monoalcohol and catalyzed by CH3SO3H is investigated, in an effort to reveal extra features of the known activated monomer/active chain‐end (AM/ACE) combined mechanism. Size‐exclusion chromatography (SEC) profiles obtained with high‐molar‐mass samples show a poly(trimethylene carbonate) (PTMC) fraction generated by AM/ACE with a molar mass that is exactly twice that of the PTMC fraction coming from pure AM. Conversely, PTMC prepared with a diol is perfectly unimodal and keeps its molar mass dispersity below 1.1. This suggests that the side AM/ACE mechanism may be a bidirectional AM mechanism, and that PTMC with a narrow unimodal molar‐mass distribution can be obtained easily from a diol regardless of this side propagation.
Structural characterization of bacterial lipopolysaccharides with mass spectrometry and on‐ and off‐line separation techniques
Authors: Kilár Anikó , Dörnyei Ágnes , Kocsis Béla 
Published: November 2012

AbstractThe focus of this review is the application of mass spectrometry to the structural characterization of bacterial lipopolysaccharides (LPSs), also referred to as “endotoxins,” because they elicit the strong immune response in infected organisms. Recently, a wide variety of MS‐based applications have been implemented to the structure elucidation of LPS. Methodological improvements, as well as on‐ and off‐line separation procedures, proved the versatility of mass spectrometry to study complex LPS mixtures. Special attention is given in the review to the tandem mass spectrometric methods and protocols for the analyses of lipid A, the endotoxic principle of LPS. We compare and evaluate the different ionization techniques (MALDI, ESI) in view of their use in intact R‐ and S‐type LPS and lipid A studies. Methods for sample preparation of LPS prior to mass spectrometric analysis are also described. The direct identification of intrinsic heterogeneities of most intact LPS and lipid A preparations is a particular challenge, for which separation techniques (e.g., TLC, slab‐PAGE, CE, GC, HPLC) combined with mass spectrometry are often necessary. A brief summary of these combined methodologies to profile LPS molecular species is provided. © 2012 Wiley Periodicals, Inc., Mass Spec Rev 32:90–117, 2013
The pore size of PLGA bone implants determines the de novo formation of bone tissue in tibial head defects in rats
Authors: Penk Anja , Förster Yvonne , Scheidt Holger A. , Nimptsch Ariane , Hacker Michael C. , Schulz‐Siegmund Michaela , Ahnert Peter , Schiller Jürgen , Rammelt Stefan , Huster Daniel 
Published: November 2012

PurposeThe influence of the pore size of biodegradable poly(lactic‐co‐glycolic acid) scaffolds on bone regeneration was investigated.MethodsCylindrical poly(lactic‐co‐glycolic acid) scaffolds were implanted into a defect in the tibial head of rats. Pore sizes of 100–300, 300–500, and 500–710 μm were tested and compared to untreated defects as control. Two and four weeks after implantation, the specimens were explanted and defect regeneration and de novo extracellular matrix generation were investigated by MRI, quantitative solid‐state NMR, and mass spectrometry.ResultsThe pore size of the scaffolds had a pronounced influence on the quantity of the extracellular matrix synthesized in the graft; most collagen was synthesized within the first 2 weeks of implantation, while the amount of hydroxyapatite increased in the second 2 weeks. After 4 weeks, the scaffolds contained large quantities of newly formed lamellar bone while the control defects were filled by inhomogenous woven bone. Best results were obtained for scaffolds of a pore size of 300–500 μm.ConclusionOur analysis showed that the structure and dynamics of the regenerated extracellular matrix was very similar to that of the native bone, suggesting that biomineralization was significantly enhanced by the choice of the most appropriate implant material. Magn Reson Med, 70:925–935, 2013. © 2012 Wiley Periodicals, Inc.
Light scattering by a metallic nanoparticle coated with a nematic liquid crystal
Authors: Yannopapas Vassilios , Fytas Nikolaos , Kyrimi Vicky , Kallos Efthymios , Vanakaras Alexandros G. , Photinos Demetri J. 
Published: November 2012

AbstractWe study the optical properties of gold nanoparticles (NPs) coated with a nematic liquid crystal (NLC) whose director field is distributed around the NP according to the anchoring conditions at the surface of the NP. The distribution of the NLC is obtained by minimization of the corresponding Frank free‐energy functional whilst the optical response is calculated by the discrete‐dipole approximation (DDA). We find, in particular, that the anisotropy of the NLC coating does not affect much the (isotropic) optical response of the NP. However, for strong anchoring of the NLC molecules on the surface of NP, the inhomogeneity of the coating which is manifested by a ring‐type singularity (disclination or Saturn ring), produces an enhancement of the extinction cross spectrum over the entire visible spectrum.
Optical properties of dye‐doped polymer films incorporating photonic nanostructures
Authors: Egami Kazutaka , Nakayama Tomoya , Kosaka Yuuka , Tomita Satoshi , Ishizumi Atsushi , Yanagi Hisao , Yamashita Ken‐ichi , Oe Kunishige 
Published: November 2012

AbstractLasing in dye‐doped polymer films incorporating twodimensional (2D) photonic nanostructures is expected to bring about a flexible and compact optical ampifier. In this work web fabricate nano‐imprint molds using electron beam lithography (EBL) together with a dry‐etching process. A photo nano‐imprint technique is used to obtain 2D nanostructures in rhodamine‐doped resin films. Narrow emission of the visible light from the surface of films incorporating 2D photonic crystals is observed using an optical excitation. Additionally we study circular dichroism (CD) in films, including “L”‐shaped holes, in which 2D space inversion symmetry is broken. A CD dip is found to be induced where the dye shows absorption The present results open a way to realize organic lasers emitting circularly‐polarized light by using a simple photo nano‐imprint technique (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Photoluminescence tailoring of InGaN/GaN quantum wells with silver nanoparticle‐assembled films
Authors: Sun Ling , Chen Ji , Liu Yijie , Tao Tao , Shi Chaochao , Shen Yan , Zheng Cheng , Wang Guanghou , Han Min 
Published: November 2012

AbstractWe present a systemic study on the tailoring of light emission properties of the InGaN/GaN quantum wells (QWs) with nanoparticle‐assembled on‐top layers. A layer of silver nanoparticles was deposited on the top of the quantum wells in gas‐phase with a dielectric spacer layer of 15nm thickness grown between them. Time‐resolved photoluminescence (PL) spectroscopy was used to study the radioactive recombination of electrons and holes in the QWs from 15 K to room temperature. A significant increasing of the internal quantum efficiency of the QWs is achieved at room temperature with a suitable nanoparticle coverage. The coupling of the spontaneous emission from InGaN QWs into the surface plasmon modes of the silver nanoparticle layers was demonstrated. (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Broadband scattering by tapered nanoantennas
Authors: Staude Isabelle , Maksymov Ivan S. , Decker Manuel , Miroshnichenko Andrey E. , Neshev Dragomir N. , Jagadish Chennupati , Kivshar Yuri S. 
Published: November 2012

AbstractWe realize a new design of tapered Yagi–Uda nanoantennas and experimentally study their far‐field light scattering. We show that in comparison with untapered structures the tapered nanoantennas exhibit broadband resonances featuring a distinct line shape. Our observations are supported by numerical calculations, which further reveal the tapered nanoantenna's wavelength‐dependent optical near‐field confinement. (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Glycerol‐3‐Phosphate Acyltransferase‐1 Gene Ablation Results in Altered Thymocyte Lipid Content and Reduces Thymic T Cell Production in Mice
Authors: Gulvady Apeksha A. , Murphy Eric J. , Ciolino Henry P. , Cabrera Robert M. , Jolly Christopher A. 
Published: November 2012

AbstractGlycerol 3‐phosphate acyltransferase‐1 (GPAT‐1) catalyzes the initial and rate‐limiting step in de novo glycerophospholipid and triacylglycerol (TAG) biosynthesis. We have previously shown that peripheral T cell proliferation and cytokine production is altered in GPAT‐1 gene‐ablated (KO) mice. This finding is important in light of the reduction in GPAT‐1 activity associated with aged T cells. To determine if the mechanism for altered peripheral T cell function is linked to altered T cell development, we assessed thymic function in 3, 6 and 16‐week old GPAT‐1 KO compared to wild type (WT) mice. At 16 weeks of age, there was a significant reduction in thymic T cell production in KO compared to WT mice but not at 6 weeks of age. The reduced thymic T cell production was associated with altered thymic development as confirmed by increased numbers of double‐negative (DN) thymocytes and a significant reduction in the double positive (DP) thymocytes suggesting a developmental block at the DN stage. This change was accompanied by an increase in the single positive CD4 subset. These changes were associated with reduced glycerophospholipid mass while thymic cortex and medulla architecture was not altered by GPAT‐1 KO. Taken together, these data suggest that GPAT‐1 deletion is capable of reducing the number of new T cells produced via alterations in membrane receptor function rather than by causing deleterious changes within the thymic microenvironment explaining in part the observed alterations in peripheral T cell function.
Trajectory planning of mobile manipulators using dynamic programming approach
Authors: Korayem M. H. , Irani M. , Charesaz A. , Korayem A. H. , Hashemi A. 
Published: November 2012

SUMMARYThis paper presents a solution for optimal trajectory planning problem of robotic manipulators with complicated dynamic equations. The main goal is to find the optimal path with maximum dynamic load carrying capacity (DLCC). Proposed method can be implemented to problems of both motion along a specified path and point-to-point motion. Dynamic Programming (DP) approach is applied to solve optimization problem and find the positions and velocities that minimize a pre-defined performance index. Unlike previous attempts, proposed method increases the speed of convergence by using the sequential quadratic programming (SQP) formulation. This formulation is used for solving problems with nonlinear constraints. Also, this paper proposes a new algorithm to design optimal trajectory with maximum DLCC for both fixed and mobile base mechanical manipulators. Algorithms for DLCC calculations in previous works were based on indirect optimization method or linear programming approach. The proposed trajectory planning method is applied to a linear tracked Puma and the mobile manipulator named Scout. Application of this algorithm is confirmed and simulation results are compared with experimental results for Scout robot. In experimental test, results are obtained using a new stereo vision system to determine the position of the robot end-effector.
Environmental variability and the transmission of haemorrhagic fever with renal syndrome in Changsha, People's Republic of China
Authors: XIAO H. , GAO L. D. , LI X. J. , LIN X. L. , DAI X. Y. , ZHU P. J. , CHEN B. Y. , ZHANG X. X. , ZHAO J. , TIAN H. Y. 
Published: November 2012

SUMMARYThe transmission of haemorrhagic fever with renal syndrome (HFRS) is influenced by climatic, reservoir and environmental variables. The epidemiology of the disease was studied over a 6-year period in Changsha. Variables relating to climate, environment, rodent host distribution and disease occurrence were collected monthly and analysed using a time-series adjusted Poisson regression model. It was found that the density of the rodent host and multivariate El Niño Southern Oscillation index had the greatest effect on the transmission of HFRS with lags of 2–6 months. However, a number of climatic and environmental factors played important roles in affecting the density and transmission potential of the rodent host population. It was concluded that the measurement of a number of these variables could be used in disease surveillance to give useful advance warning of potential disease epidemics.
Testing for Chlamydia trachomatis: time trends in positivity rates in the canton of Basel-Stadt, Switzerland
Authors: SCHMUTZ C. , BURKI D. , FREI R. , MÄUSEZAHL-FEUZ M. , MÄUSEZAHL D. 
Published: November 2012

SUMMARYNational health statistics report a 2·5-fold increase in laboratory-confirmed Chlamydia trachomatis (CT) cases over the last decade in Switzerland where no CT screening programme exists. We obtained essential denominator information to describe the epidemiology of CT in the canton of Basel-Stadt, an urban canton in north-western Switzerland. Laboratories reporting at least two CT infections from Basel-Stadt residents to the SFOPH in 2010 provided demographic and test-related data. CT positivity rates were calculated for 2002–2010. The influences of test year, age, sex and laboratory on CT positivity were investigated in a multivariable model. Positivity differed between sexes and age groups. In our sample of 32 034 records, female and male CT positivity rates were 4·7% and 11·1%, respectively. Test year was significantly associated with test outcome in the multivariable analysis but no time trend was observed. CT positivity did not change over the past 9 years in Basel-Stadt. In contrast to other European countries without CT screening, we found no evidence that the observed increase of Chlamydia cases in the national notification system represents an epidemiological trend, but rather results from an increased testing frequency.
Diversification in heavy-tailed portfolios: properties and pitfalls
Authors: Mainik Georg , Embrechts Paul 
Published: November 2012

AbstractWe discuss risk diversification in multivariate regularly varying models and provide explicit formulas for Value-at-Risk asymptotics in this case. These results allow us to study the influence of the portfolio weights, the overall loss severity, and the tail dependence structure on large portfolio losses. We outline sufficient conditions for the sub- and superadditivity of the asymptotic portfolio risk in multivariate regularly varying models and discuss the case when these conditions are not satisfied. We provide several examples to illustrate the resulting variety of diversification effects and the crucial impact of the tail dependence structure in infinite mean models. These examples show that infinite means in multivariate regularly varying models do not necessarily imply negative diversification effects. This implication is true if there is no loss-gain compensation in the tails, but not in general. Depending on the loss-gain compensation, asymptotic portfolio risk can be subadditive, superadditive, or neither.
Spin-dependent six-fold symmetric anisotropic magnetoresistance in epitaxial magnetite films
Authors: Li Peng , Sun M Y , Jin C , Bai H L 
Published: November 2012

Abstract
Six-fold anisotropic magnetoresistance (AMR) was observed in epitaxial Fe3O4(1 1 1) films on conductive ZnO (0 0 0 1), while the current flowed perpendicularly to the film plane and the magnetic field rotated in the film plane, demonstrating the close relation between AMR and magnetocrystalline anisotropy. The spin injection efficiency of Fe3O4 films was modulated from 60% to 20% with increasing underlayer ZnO surface roughness through changing the sputtering pressure. Larger AMR is observed in epitaxial Fe3O4(1 1 1) films with higher spin injection efficiency. Under the induction of a magnetic field and magnetocrystalline anisotropic fields along the easy axis, it is supposed that the scattering of carriers by the noncollinear moments near antiphase boundaries is weaker for the films with higher spin injection efficiency.
Improved performance of top-emitting oxide-confined polyimide-planarized 980 nm VCSELs with copper-plated heat sinks
Authors: AL-Omari A N , Alias M S , Ababneh A , Lear K L 
Published: November 2012

Abstract
Top-emitting, oxide-confined, copper-plated 980 nm vertical-cavity surface-emitting lasers (VCSELs) with improved performance were fabricated and characterized. Annular copper-plated heat sinks reduced the device's thermal resistance and increased the output optical power and the bias current density at which the output optical power saturates. Increasing the plated heat sink radii from 0 to 8 µm greater than the mesa diameter for VCSELs with 26 µm mesa diameter and 8 µm active area diameter reduced the measured thermal resistance by 65% and increased the bias current density at which the output optical power saturates by 62%, which increased the maximum output optical power achieved by 162%. VCSELs with active area diameter and heat sink overlap of 8 µm demonstrated ∼64% decrease in active region temperature at the maximum output optical power compared with devices with no heat sink overlap. A 29% improvement in the devices' modulation bandwidth was calculated due to reduced temperature and increased power. Devices with identical mesa diameters of 26 µm and different heat sink overlaps exhibited a threshold current density and a total series resistance of (1.25 ± 4%) kA cm−2 and ∼95 Ω, respectively. Simple VCSEL L–I and thermal models were used to simulate the VCSEL's L–I performance at elevated ambient temperatures. Good agreement between measured and simulated characteristics was obtained. Detailed protocols for critical fabrication steps are presented.
Interface and transport properties of GaN/graphene junction in GaN-based LEDs
Authors: Wang Liancheng , Zhang Yiyun , Li Xiao , Liu Zhiqiang , Guo Enqing , Yi Xiaoyan , Wang Junxi , Zhu Hongwei , Wang Guohong 
Published: November 2012

Abstract
A normalized circular transmission line method pattern with uniform interface area was developed to obtain contact resistances of p-, u-, n-GaN/graphene contacts (p, u and n represent p-type doped, unintentionally doped and n-type doped, respectively) and N-polar u-, n-GaN/graphene contacts in GaN-based LEDs. The resistances of the graphene/GaN contacts were mainly determined by the work function gap and the carrier concentration in GaN. Annealing caused diffusion of metal atoms and significantly influenced the interface transport properties.
Sputtering yields and surface modification of poly(methyl methacrylate) (PMMA) by low-energy Ar+/

ion bombardment with vacuum ultraviolet (VUV) photon irradiation
Authors: Yoshimura Satoru , Tsukazaki Yasuhiro , Kiuchi Masato , Sugimoto Satoshi , Hamaguchi Satoshi 
Published: November 2012

Abstract
Sputtering yields and surface modification of poly(methyl methacrylate) (PMMA) by mono-energetic ion beams and/or vacuum ultraviolet (VUV) light are studied with the use of a low-energy mass-selected ion beam system. Sputtering yields of PMMA by Ar+ or

ion beams are obtained as functions of ion incident energy below 500 eV. It is found that surface modification of PMMA due to

ion incidence is limited to the region near the film surface, whereas that due to Ar+ ion incidence is seen in a relatively deeper region of the film, where PMMA is partially carbonized and diamond-like carbon (DLC) is formed. Under the conditions of incident energies and fluxes of ion and VUV light used in the experiments, the sputtering yield of PMMA by simultaneous incidence of VUV light and

ions is found to be nearly equal to the sum of the yields by separate incidences of VUV light and

ions. Some of the etching characteristics observed in this study (such as DLC formation by ion sputtering) may be shared by a wide range of organic polymers that have main chain structures similar to those of PMMA.
Application of Vector Autoregression to Dynamic Relationships within the U.S. Dairy Sector
Authors: Haden Kimberly L. , VanTassell Larry W. 
Published: November 2012

AbstractNumerous studies have econometrically analyzed the dairy sector and effects of alternative dairy policies. While many of these studies have included dynamic aspects, often strict a priori assumptions have been made concerning which variables enter each equation and the lag length or the structure of the lags. Vector autoregression is a dynamic multiequation technique that places few a priori restrictions on the system of relationships. This study attempts to analyze several of the dynamic relationships in the dairy sector utilizing a vector autoregression.
New York Milk Supply with Bovine Growth Hormone
Authors: Magrath William B. , Tauer Loren W. 
Published: November 2012

AbstractNew York milk supply functions with and without bovine growth hormone (somatotropin) were estimated by a sector linear programming model. High government price supports make bGH profitable and induce significant increases in output. Reduction or elimination of price supports greatly diminishes bGH as a viable technology except with high‐producing herds or at low bGH prices.