bluuebunny/crossref_metadata_2025 huggingface dataset:
Relaxivity of gadolinium complexes detected by atomic magnetometry
Authors: Michalak David J. , Xu Shoujun , Lowery Thomas J. , Crawford C. W. , Ledbetter Micah , Bouchard Louis‐S. , Wemmer David E. , Budker Dmitry , Pines Alexander
Published: March 2011

Laser atomic magnetometry is a portable and low‐cost yet highly sensitive method for low magnetic field detection. In this work, the atomic magnetometer was used in a remote‐detection geometry to measure the relaxivity of aqueous gadolinium‐diethylenetriamine pentaacetic acid Gd(DTPA) at the Earth's magnetic field (40 μT). The measured relaxivity of 9.7 ± 2.0 s−1 mM−1 is consistent with field‐cycling experiments measured at slightly higher magnetic fields, but no cryogens or strong and homogeneous magnetic field were required for this experiment. The field‐independent sensitivity of 80 fT Hz–1/2 allowed an in vitro detection limit of ∼ 10 μM Gd(DTPA) to be measured in aqueous buffer solution. The low detection limit and enhanced relaxivity of Gd‐containing complexes at Earth's field motivate continued development of atomic magnetometry toward medical applications. Magn Reson Med 66:603–606, 2011. © 2011 Wiley‐Liss, Inc.
Utility of ultrasound‐guided surface electrode placement in lateral femoral cutaneous nerve conduction studies
Authors: Boon Andrea J. , Bailey Peter W. , Smith Jay , Sorenson Eric J. , Harper C. Michel , Hurdle Mark F.
Published: March 2011

Introduction: Meralgia paresthetica is a common clinical complaint for which some patients ultimately undergo surgical treatment. The lateral femoral cutaneous nerve (LFCN) has been difficult to reliably test electrophysiologically, likely due to anatomic variability and lack of responses in asymptomatic obese subjects. Methods: We compared a novel ultrasound‐guided antidromic sensory nerve conduction study (NCS) with a technique described previously in a population of normal subjects, of whom 50% had body mass indices within the obese range (>27.5). Results: Responses were obtained in at least 92% of subjects using either technique, and 92% of normal subjects had <60% interside variability using the ultrasound‐guided technique. Conclusions: LFCN sensory nerve action potentials can be obtained in the vast majority of normal subjects, even in an obese population and can provide a useful sensory NCS for evaluation of mid‐lumbar radiculopathy, plexopathy, or meralgia paresthetica. Muscle Nerve, 2011
The thymus in myasthenia gravis: Site of “innate autoimmunity”?
Authors: Cavalcante Paola , Le Panse Rozen , Berrih‐aknin Sonia , Maggi Lorenzo , Antozzi Carlo , Baggi Fulvio , Bernasconi Pia , Mantegazza Renato
Published: March 2011

Myasthenia gravis (MG) is an autoimmune disorder caused, in most cases, by autoantibodies against components of the neuromuscular junction, frequently the acetylcholine receptor (AChR), and less often the muscle‐specific kinase receptor. The thymus plays a major role in the pathogenesis of MG with anti‐AChR antibodies: it shows marked pathologic alterations (hyperplastic or tumoral) in most AChR‐positive patients and contains the elements required to initiate and sustain an autoimmune reaction (AChR autoantigen, AChR‐specific T cells, and autoantibody‐secreting plasma cells). In this study we review early and more recent findings implicating the thymus as site of AChR autosensitization in MG and briefly discuss the therapeutic role of thymectomy. We also summarize data showing that the MG thymus is in a state of chronic inflammation, and we review emerging evidence of a viral contribution to the onset and maintenance of the thymic autoimmune response. Muscle Nerve, 2011
Effect of botulinum neurotoxin treatment in the lateral spread monitoring of microvascular decompression for hemifacial spasm
Authors: Habeych Miguel E. , Shah Aalap C. , Nikonow Tara N. , Balzer Jeffrey R. , Crammond Donald J. , Thirumala Parthasarathy D. , Kassam Amin , Horowitz Michael
Published: March 2011

Introduction: Botulinum neurotoxin (BtNtx) treatment for hemifacial spasm (HFS) prior to microvascular decompression (MVD) is hypothesized to be a factor in the variability of intraoperative neurophysiological monitoring (IONM) during this procedure. Methods: We analyzed 282 MVDs performed at the University of Pittsburgh Medical Center between January 1, 2000 and December 31, 2007. We retrospectively compared the lateral spread response (LSR) in the mentalis muscle when stimulus‐triggered electromyography (EMG) was elicited from the facial nerve. Previous BtNtx treatment was the grouping factor. Results: Baseline LSR amplitudes during MVD (prior BtNtx: mean = 341.47 μV; no BtNtx: mean = 241.81 μV) were significantly different between groups (df = 1,281; t = −2.463; P = 0.014). Comparisons of latency and current threshold at baseline, as well as HFS disappearance or LSR persistence after the procedure, did not achieve statistical significance. Conclusions: HFS patients treated with BtNtx prior to MVD demonstrated higher LSR baseline amplitudes during IONM. This could be related to muscle poly‐reinnervation after recovery from repeated BtNtx use. Muscle Nerve, 2011
A comparative study of dynamic contrast‐enhanced MRI parameters as biomarkers for anti‐angiogenic drug therapy
Authors: Koh Tong San , Thng Choon Hua , Hartono Septian , Tai Bee Choo , Rumpel Helmut , Ong Ai Bee , Sukri Norita , Soo Ross A. , Wong Chuing Ing , Low Albert S. C. , Humerickhouse Rod A. , Goh Boon Cher
Published: March 2011

The aim of the present study was to compare three tracer kinetics methods for the analysis of dynamic contrast‐enhanced (DCE) MRI data, namely the generalized kinetics model, the distributed‐parameter model and the initial area under the tumor tracer curve (IAUC) method, in a Phase I study of an anti‐angiogenic drug ABT ‐869; and to explore their utility as biomarkers. Twenty‐eight patients with a range of tumors formed the study population. DCE MRI performed at baseline and 2 weeks post‐treatment was analyzed using all three methods, yielding percentage changes for various tracer kinetics parameters. Correlation analyzes were performed between these parameters and in relation to drug exposure. The association of these parameters with time‐to‐progression was examined using receiver‐operating characteristic and Kaplan–Meier curves. Significant correlation with drug exposure was found for the following parameters: normalized IAUC (IAUCnorm), fractional interstitial volume ve, fractional intravascular volume v1 and permeability PS. However, only ve and PS were effective in predicting late progression. A decrease in ve of more than 1.7% and a decrease in PS of more than 25.1% observed at 2 weeks post‐treatment could be associated with late progression. All three tracer kinetics methods have biomarker potential for assessing the effects of anti‐angiogenic therapy. Copyright © 2011 John Wiley & Sons, Ltd.
Variational time integrators for finite‐dimensional thermo‐elasto‐dynamics without heat conduction
Authors: Mata Pablo , Lew Adrián J.
Published: March 2011

This paper focuses on the formulation of variational integrators (VIs) for finite‐dimensional thermo‐elastic systems without heat conduction. The dynamics of these systems happen to have a Hamiltonian structure, after thermal displacements are introduced. It is then possible to formulate integrators by taking advantage of standard methods in VI. The class of integrators we construct have some remarkable features: (a) they are symplectic, (b) they exactly conserve the entropy of the system, or in other words, they exactly satisfy the second law of the thermodynamics for reversible adiabatic processes, (c) they nearly exactly conserve the value of the energy for very long times and (d) they exactly conserve linear and angular momentum. We first describe how to adapt any VI for the classical mechanical systems to integrate adiabatic thermo‐elastic ones, and then formulate three new types of integrators. The first class, based on a generalized trapezoidal rule, gives rise to two first order, explicit integrators, and a second order, implicit one. By composing then the two first‐order integrators we construct a second order, explicit one. Finally, we formulate a fourth order, implicit integrator, which is a symplectic partitioned Runge–Kutta method. The performance of these new algorithms is showcased through numerical examples. Copyright © 2011 John Wiley & Sons, Ltd.
Cholinesterase inhibitor use in Alzheimer's disease: the EPIFARM‐Elderly Project
Authors: Franchi Carlotta , Lucca Ugo , Tettamanti Mauro , Riva Emma , Fortino Ida , Bortolotti Angela , Merlino Luca , Pasina Luca , Nobili Alessandro
Published: March 2011

Purpose

This study was designed to examine the prevalence of cholinesterase inhibitor (ChEI) use and the proportions of patients treated with ChEIs by using an administrative prescription database of prevalent and incident cases of mild to moderate Alzheimer's disease (AD) in relation to age and duration of therapy.

Methods

A prospective observational study covering individuals aged 65 years or older who received at least one prescription of ChEIs between 1 January 2002 and 31 December 2007 was conducted in three health administrative areas in the Lombardy Region, Italy.

Results

The prevalence of those who received at least one prescription for ChEIs rose from 0.5% in 2002 to 0.7% in 2004, reaching a plateau. Among estimated prevalent cases of mild to moderate AD, the prevalence of patients who received at least one prescription of ChEIs varied in different age groups, rising in those over 80 years and falling slightly in those under 80 years, particularly in patients aged 65–69 years (test for trend, p < 0.001). Among estimated incident cases, the percentage of newly treated patients dropped from 12% in 2004 to 8% in 2007, as well as within each age group (test for trend, p < 0.001). In the cohort of incident users, nearly 40% of patients who started treatment in 2004 were still in treatment 3 years later.

Conclusions

The prescription prevalence of ChEIs increased up to 2004, then reached a plateau. This might reflect the practical response of physicians and patients to the controversy and uncertainty surrounding the clinical value of these expensive drugs for the treatment of AD. Copyright © 2011 John Wiley & Sons, Ltd.
Solid‐phase extrusion of polyamide‐6 by using combined deformation schemes
Authors: Beloshenko V.A. , Varyukhin V.N. , Voznyak A.V. , Voznyak Yu.V.
Published: March 2011

Potentialities of new combined deformation schemes, including the solid state extrusion through conical die (ED) and equal‐channel multiple angle extrusion (ECMAE) implemented in different sequence to modify structure and properties of semicrystalline polymers, have been studied for polyamide‐6 as an example. It is shown that deformation by the ED‐ECMAE scheme gives the best complex of physical and mechanical properties. A significant improvement in elastic and strength properties of polyamide‐6 with the conserved high level of plastic characteristics has been observed. There was only a slight anisotropy and dispersion of microhardness across the extrudates. A more uniform oriented structure with lamellae orientation along extrudate's axis has been formed in semicrystalline polymer because the ED‐ECMAE scheme implementation. POLYM. ENG. SCI., 2011. © 2011 Society of Plastics Engineers
Biaxial stretching of polymers using a novel and versatile stretching system
Authors: Qaiss A. , Bousmina M.
Published: March 2011

A novel versatile biaxial stretching module that can be adapted to any uniaxial traction testing machine was developed to generate consecutive or simultaneous two‐directional biaxial stretching at various stretching ratios and draw rates. The module allows direct conversion of the uniaxial machine displacement to transverse displacement with a precise adjustment of the stretch ratio between the transverse of the longitudinal strains. Additionally, the developed device allows simultaneous measurements of films mechanical properties in the two directions. The efficiency and the accuracy of the module were verified without and with standard polymer films such as polypropylene and high density polyethylene. POLYM. ENG. SCI., 2011. © 2011 Society of Plastics Engineers
Stabilizations of molecular structures and mechanical properties of PVC and wood/PVC composites by Tinuvin and TiO2 stabilizers
Authors: Chaochanchaikul Kantima , Sombatsompop Narongrit
Published: March 2011

Three different UV stabilizers, 2‐(2H‐benzotriazol‐2‐yl)‐4,6‐ditertpentylphenol (Tinuvin XT833), 2‐(2H‐benzotriazol‐2‐yl)‐p‐cresol (Tinuvin P), or rutile–titanium dioxide (TiO2) were incorporated into poly(vinyl chloride) (PVC) and wood/PVC (WPVC) composite, and mechanical and physical properties and photostabilities were monitored. The polyene and carbonyl sequences of PVC increased with UV weathering time and with presence of wood flour. The yellowness index increased because of polyene and carbonyl productions, whereas the brightness increased because of the photobleaching of lignin in wood. The photostabilities of PVC and WPVC could be improved through the use of UV stabilizers. Tinuvin P was recommended in this work as the most effective stabilizer for PVC and WPVC composites. The stabilization effect was interfered by presence of wood particles. The mechanical property changes corresponded well to the structural changes under UV for neat PVC. For WPVC composites, the presence of wood particles played more significant effect on the mechanical properties during UV aging than the UV stabilizer. POLYM. ENG. SCI., 2011. © 2011 Society of Plastics Engineers
Long‐term mechanical behavior of aramid fibers in seawater
Authors: Derombise G. , Chailleux E. , Forest B. , Riou L. , Lacotte N. , Vouyovitch Van Schoors L. , Davies P.
Published: March 2011

Aramid fibers are today proposed in ropes and cables for marine applications. As these highly crystalline materials are loaded in tension for a longer period in seawater, their long‐term mechanical behavior has to be understood. However, the response is time‐dependent and exhibits a nonlinear effect with stress. In this study, two types of aramid fibers are studied: Twaron and Technora. Mechanical properties are measured using static tensile tests and creep‐recovery tests. A nonlinear viscoelastic–viscoplastic model, based on the Schapery formulation, allows discriminating between the instantaneous and the time‐dependent response as well as the reversible and nonreversible phenomena (plasticity). First, this procedure allows the overall mechanical behavior of the fibers to be compared, considering creep rate, plasticity, and instantaneous moduli. Then, using these parameters, the effect of the testing condition, air or seawater is studied. Finally, the effect of aging in seawater is quantified for both fibers. POLYM. ENG. SCI., 2011. © 2011 Society of Plastics Engineers
Experimental study on gap bridging in contour laser transmission welding of polycarbonate and polyamide
Authors: Chen Mingliang , Zak Gene , Bates Philip J. , Baylis Bobbye , McLeod Martin
Published: March 2011

Laser transmission welding (LTW) is a technique for joining thermoplastics. During contour LTW, any gaps or spaces between the two parts along the weld seam may prevent a weld from forming. This work presents an experimental study on the effects of material property (carbon black level, glass fibers, and crystallinity), process parameters (laser scan power and scan speed), and weld gap thickness on the strength and microstructure of contour welds made of polycarbonate (PC), polyamide 6 (PA6), and PA6 reinforced with 30% glass fiber. Lap specimens, with weld lines parallel to the load direction during mechanical testing, were used to assess the weld shear strength. The results indicated that low concentrations of laser absorbing pigment accompanied by high laser power improve gap bridging. The study also indicated that a novel noncontact test method can be used to search for the optimized process parameters for gap bridging. The maximum gaps bridged were 0.2, 0.4, and 0.25 mm for PC, PA6, and reinforced polyamide 6, respectively. POLYM. ENG. SCI., 2011. © 2011 Society of Plastics Engineers
Tandem cationic and sol–gel photopolymerizations of a vinyl ether alkoxysilane
Authors: Chemtob Abraham , Belon Cindy , Croutxé‐Barghorn Céline , Rigolet Séverinne , Vidal Loïc , Brendlé Jocelyne , Mandel Jérémie , Blanchard Nicolas
Published: March 2011

In the present study, a novel single hybrid monomer combining a vinylether and trimethoxysilane groups in the same molecule was synthesized by chemoselective hydrosilation and subjected to UV‐irradiation in the presence of a triarylsulfonium salt. Through the UV‐decomposition of this photoacid generator, two acid‐catalyzed processes occurred simultaneously: the cationic polymerization of the vinyl ether functions and the sol–gel polycondensation of the alkoxysilyl groups, leading to a type II polyvinyl‐polysilicate nanocomposite film. Both reaction kinetics were efficiently monitored by real‐time Fourier transform infrared spectroscopy, and the influence of different key experimental parameters was investigated (laminated conditions, UV irradiation equipment, and film thickness). A particular attention was also given to the complete characterization of the hybrid microstructure by associating 29Si and 13C solid‐state NMR. POLYM. ENG. SCI., 2011. © 2011 Society of Plastics Engineers
Synthesis, self‐assembly behavior, and biological application of a new photochromic azo amphiphilic diblock copolymer
Authors: Ding Han , Wang Zheng , Sheng Lijiao , Song Gongwu
Published: March 2011

Polymer (N,N‐dimethyl‐ethylamine methacrylate)‐block‐poly{6‐[4‐(4‐methoxy phenyl‐azo) phenoxy] hexylacrylate} p(DMAEMA
m‐b‐AZOM
n) was synthesized by successive reversible addition‐fragmentation chain transfer polymerization in the hydrothermal reactor. The products were characterized by hydrogen nuclear magnetic resonance, differential scanning calorimetry, gel permeation chromatography, and ultraviolet and visible absorption spectroscopy (UV‐vis). In H2O/THF mixture, we found amphiphilic p(DMAEMA
m‐b‐AZOM
n) self‐assembles occurred. p(DMAEMA79‐b‐AZOM7) self‐assembled into rods, p(DMAEMA79‐b‐AZOM5) self‐assembled into giant microspheres with rods wind around, p(DMAEMA79‐b‐AZOM2) self‐assembled into microspheres. Photochromic behaviors of the polymers in different environments were investigated. We found the colors of diblock copolymers in films changed from yellow to orange after irradiation by ultraviolet and visible (UV) light. The rates of trans‐cis photoisomerization in films were almost the same for the three p(DMAEMA
m‐b‐AZOM
n) copolymers. The rates in aqueous micellar solutions were only marginally faster than those in films for all the three diblock copolymers. The observation of a sizable rate difference in different environments for p(DMAEMA
m‐b‐AZOM
n) suggested that a rotational mechanism might be operative for these water‐soluble amphiphilic diblock copolymers. The self‐assembly behaviors of three copolymers and the application of p(DMAEMA79‐b‐AZOM2) microspheres in biochemistry were investigated in present work. POLYM. ENG. SCI., 2011. © 2011 Society of Plastics Engineers
Montmorillonite clay nanocomposites based on vinyl pyridine‐styrene‐butadiene terpolymer (VPR)/acrylonitrile‐butadiene rubber (NBR) blend
Authors: Chakraborty Sugata , Kar Saptarshi , Dasgupta Saikat , Mukhopadhyay Rabindra , Chauhan Narendra P.S. , Ameta Suresh C. , Bandyopadhyay Samar
Published: March 2011

This study describes a novel route to synthesize vinyl pyridine‐styrene‐butadiene terpolymer rubber (VP rubber) montmorillonite clay nanocomposites by latex blending technique. The pyridine moiety of the VP rubber was modified with methyl iodide to form the pyridinium ion during latex blending. Cation exchange reaction of the pyridinium ion of the VP rubber latex with sodium montmorillonite occurred during latex stage mixing which helped to form VP rubber‐montmorillonite clay nanocomposites. Coagulation of the latex‐clay slurry produced nanocomposites master batch. The master batch was compounded with acrylonitrile butadiene rubber (NBR). Fourier Transform Infrared Spectroscopy (FTIR) confirmed the modification of the pyridine moiety of VP rubber. Wide angle X‐ray diffraction (WAXD), scanning electron microscopy‐energy dispersive X‐ray spectrophotometry (SEM‐EDS) and transmission electron microscopy (TEM) provided the evidences of formation of nanocomposite. Remarkable improvements in the mechanical properties were found by addition of small amount of modified clay. POLYM. ENG. SCI., 2011. © 2011 Society of Plastics Engineers
Control of the migration behavior of slip agents in polyolefin‐based films
Authors: Llop Cosme , Manrique Antonio , Navarro Rodrigo , Mijangos Carmen , Reinecke Helmut
Published: March 2011

Unsaturated long‐chain carboxylic acid amides like Erucamide are very efficient as slipping agents in polyolefin films and other polymers. A problem is the uncontrolled migration of this additive. The main goal of the present project was therefore the study and understanding of Erucamide diffusion through the film and how the diffusion behavior can be altered using plasma surface treatments or additional additives with varying molecular weights and hydrophilic–hydrophobic balance. The determination of the amount of Erucamide and co‐additive at the surface of the polymer film has been carried out by attenuated total reflectance (ATR) spectroscopy. The study shows that the system is highly sensible to the chemical structure of the surface modifier and particularly their hydrophilic–hydrophobic balance and their molecular weight. The most efficient surface modifier tested in this work was a block‐co‐oligomer with 50% polyethylene (PE) and 50% polyethylene oxide (PEO) sequences that can successfully be used to reduce Erucamide migration at both sides of the three‐layer‐PE‐films. POLYM. ENG. SCI., 2011. © 2011 Society of Plastics Engineers
Fabrication of nano/microfiber scaffolds using a combination of rapid prototyping and electrospinning systems
Authors: Park Su A. , Kim Hyo Joo , Lee Su Hee , Lee Jun Hee , Kim Hyung Keun , Yoon Taek Rim , Kim WanDoo
Published: March 2011

Tissue‐engineered scaffolds require an adequate three‐dimensional (3‐D) structure for cell growth and attachment. Solid freeform fabrication can provide the interconnected pore to induce the cell ingrowth, and electrospinning technique can make the nanofiber web with high surface for cell attachment. In this study, 3‐D polycaprolactone (PCL) scaffolds were fabricated using a rapid prototyping plotting system coupled with an electrospinning apparatus. Scanning electron micrographs showed that these hybrid scaffolds had a regular microfiber structure with interconnected pores and a nanofiber distribution appropriate for cell attachment. Scaffolds were seeded with MG63 cells for in vitro study and implanted in the tibia of rabbit for in vivo study. The resulting structure also facilitated cell adhesion, proliferation, and differentiation as evidenced by biochemical analyses and confocal microscopy. The hybrid scaffolds also exhibited good biocompatibility and osteoconductivity in animal studies. POLYM. ENG. SCI., 2011. © 2011 Society of Plastics Engineers
Stereoselectivity and kinetics of [4 + 2] cycloaddition reaction of cyclopentadiene to para‐substituted E‐2‐arylnitroethenes
Authors: Jasiński Radomir , Kwiatkowska Magdalena , Barański Andrzej
Published: March 2011

In spite of diversified electrophilicity of E‐2‐arylnitroethenes, their [4 + 2] cycloaddition reactions with cyclopentadiene leads to the corresponding 6‐endo‐aryl‐5‐exo‐nitronorbornenes and 6‐exo‐aryl‐5‐endo‐nitronorbornenes as the only reaction products. Stereoselectivity, substituent and solvent effects, and activation parameters, suggest that these reactions occur via a synchronous concerted mechanism on both competing pathways. The experimental results obtained are consistent with the data from B3LYP/6‐31G(d) calculations. Due to high electrophilicity of E‐2‐arylnitroethenes, the reactions studied should be considered as polar [4 + 2] cycloadditions. Copyright © 2011 John Wiley & Sons, Ltd.
Silane gas venting/treatment lessons learned and best practices
Authors: VanOmmeren James
Published: March 2011

Silane (SiH4) is a pyrophoric gas that requires special equipment and handling precautions to manage safely. Unfortunately, many users have had various serious accidents with SiH4 equipment since popular inception of the gas in the late 1960s for semiconductor manufacture, including at least eight fatalities and many injuries. SiH4 usage is growing tremendously worldwide in various industries, including semiconductor, flat‐panel display, photovoltaic cell, and specialty glass manufacturing. Significant uses of SiH4 also require systems with the capability to safely vent or treat SiH4 gas—such as residual venting during container changes or emergency venting. Six hazards associated with venting and treating SiH4 gas are presented in detail. Each hazard is illustrated by an actual venting incident and resulting lessons learned are discussed. Preferred venting and treatment solutions are detailed and a silane disposal system design work process is presented. Although the article is specific to pure SiH4, it has relevance to both venting and treatment of pyrophoric gases and flammable gases that possess relatively low‐ignition energies. © 2011 American Institute of Chemical Engineers Process Saf Prog 2011
Tensor‐resolved stress analysis in silicon MEMS device by polarized Raman spectroscopy
Authors: Miyatake Takahiro , Pezzotti Giuseppe
Published: March 2011

A polarized Raman method is described to measure the tensor elements of the residual stress state (induced upon fabrication) in a thin silicon plate, a suspended structure belonging to the test element group (TEG) chip of a microelectromechanical system (MEMS). The residual stress data experimentally retrieved by the Raman methodology are compared to those calculated according to a finite element model (FEM) of the MEMS. While FEM required the input of the thermal history experienced by the suspended bridge silicon structure, experimental Raman data directly revealed the stress tensor components without any assumption needed. An improved analytical procedure is shown that enables retrieving individual stress tensor components from polarized Raman light. Tensor‐resolved Raman analysis, capable of de‐coupling the hydrostatic and the deviatoric parts of the stress tensor, represents a key‐point in rationalizing the role of thermal history as well as of other processing parameters on the development of internal stress in MEMS devices made of silicon.
Growth and magnetic properties of bulk electron doped La0.7Ce0.3MnO3 manganites
Authors: Sergeenkov S. , Cardoso C. A. , Andreeta M. R. B. , Hernandes A. C. , Leite E. R. , Moreira F. M. Araújo‐
Published: March 2011

We report on the growth of bulk samples (composite fibers) of the nominal composition La0.7Ce0.3MnO3 (LCMO) manganites (with Curie temperature TC,max = 300 K) by using the laser heated pedestal growth (LHPG) technique. Samples composition was verified through scanning electron microscopy with energy dispersive X‐ray (EDX) analysis. The magnetic behavior of the fibers was probed by magnetization measurements. In addition to a weak ferromagnetic transition at TC0 = 45 K (due to MnO2 impurities), two more transitions with TC1 = 126 K and TC2 = 180 K were identified and linked to regions with cerium concentration of x = 0.063 and 0.13, respectively.
Effects of dopants on the synthesis of Pb(Mg1/3Nb2/3)O3‐PbTiO3 ceramics by the reaction‐sintering method
Authors: Fang Bijun , Ding Chenlu , Wu Jian , Du Qingbo , Ding Jianning
Published: March 2011

Sintering aid‐doped 0.8Pb(Mg1/3Nb2/3)O3‐0.2PbTiO3 (0.8PMN‐0.2PT) relaxor‐based ferroelectric ceramics were prepared by the reaction‐sintering method. X‐ray diffraction (XRD) measurement, SEM observation, and density measurement confirmed that the Li2CO3‐ and CuO‐doped 0.8PMN‐0.2PT ceramics exhibit pure rhombohedral perovskite structure, rather homogenous micromorphology and high relative density. As compared to the undoped 0.8PMN‐0.2PT ceramics, the Li2CO3‐ and CuO‐doped 0.8PMN‐0.2PT ceramics exhibit enhanced dielectric diffused and frequency dispersion, improved ferroelectric property, and piezoelectric property, while as the sintering temperature is decreased greatly. Therefore, Li2CO3 and CuO are effective sintering aids for the PMN‐PT ceramics prepared by the reaction‐sintering method, which exhibit promising applications in the electronic ceramic industries.
Luminescent properties of tris(2,2′‐bipyridine) dichloro ruthenium(II) hexahydrate under high pressure
Authors: Wang Z. P. , Zhang Z. M. , Zhang J. W. , Sun X. , Ding Z. J.
Published: March 2011

The luminescence properties of tris(2,2′‐bipyridine) dichloro ruthenium(II) hexahydrate ([Ru(bpy)3]2+ Cl2·6H2O) were studied with a diamond anvil cell (DAC) under quasi‐hydrostatic pressure. The emission intensity increases with elevated pressure and the fluorescence maxima was observed at 1.7 GPa. The emission intensity then drops down with further compression. The emission peak position shift to higher energy side (blue shift) firstly, and then shift to lower energies (red shift) at pressures above 1.4 GPa. Two phase transitions occur at about 1.4 and 6.6 GPa. The emission almost quench at 10.4 GPa. This behavior may be due to the reduction of Ru ion coordination number; the 2,2′‐bipyridine molecules are isolated from [Ru(bpy)3]2+ and thus influence the emission properties.
Modulation of Transient Receptor Potential (TRP) Channels by Chinese Herbal Extracts
Authors: Zhang Yansong , Sreekrishna Koti , Lin Yakang , Huang Luqi , Eickhoff David , Degenhardt Chuck , Xu Tao
Published: March 2011

Many transient receptor potential (TRP) channels are activated or blocked by various compounds found in plants. TRPV1 (transient receptor potential vanilloid 1) and transient receptor potential ankyrin 1 (TRPA1) are members of the TRP ion channel family which are implicated as cough receptors. Several plant extracts are used in traditional Chinese medicine (TCM) for the treatment of cough. This report evaluated the effect of four such herbals for their effect on cough receptors. Of the herbals tested, Pipaye (Folium Eriobotryae) extracts, especially the 50% ethanol extract, showed the highest activity for the suppression of TRPV1 activation by its agonist capsaicin. Pipaye is able to elicit Ca‐flux through TRPV1 as well as through unknown channels. Thus the inhibition of capsaicin elicited Ca‐flux in TRPV1 cells by Pipaye is largely due to desensitization of the receptor. Pipaye extract has a similar, but less pronounced effect, on TRPA1. Also tested were three pure components, ursolic acid (UA), peimine (PM) and peiminine (PN) derived from TCM for their effect on cough receptors. Only UA tested at 100 μm showed potent antagonistic activity towards TRPV1. Both PM and PN had no activity when tested alone, however, both were able to enhance the UA effect. A similar, but less marked, inhibition was also noted for TRPA1. Copyright © 2011 John Wiley & Sons, Ltd.
Fixed‐wing attitude estimation using temporal tracking of the horizon and optical flow
Authors: Dusha Damien , Mejias Luis , Walker Rodney
Published: March 2011

A method has been developed for estimating pitch angle, roll angle, and aircraft body rates based on horizon detection and temporal tracking using a forward‐looking camera, without assistance from other sensors. Using an image processing front end, we select several lines in an image that may or may not correspond to the true horizon. The optical flow at each candidate line is calculated, which may be used to measure the body rates of the aircraft. Using an extended Kalman filter (EKF), the aircraft state is propagated using a motion model and a candidate horizon line is associated using a statistical test based on the optical flow measurements and the location of the horizon. Once associated, the selected horizon line, along with the associated optical flow, is used as a measurement to the EKF. To test the accuracy of the algorithm, two flights were conducted, one using a highly dynamic uninhabited airborne vehicle (UAV) in clear flight conditions and the other in a human‐piloted Cessna 172 in conditions in which the horizon was partially obscured by terrain, haze, and smoke. The UAV flight resulted in pitch and roll error standard deviations of 0.42 and 0.71 deg, respectively, when compared with a truth attitude source. The Cessna flight resulted in pitch and roll error standard deviations of 1.79 and 1.75 deg, respectively. The benefits of selecting and tracking the horizon using a motion model and optical flow rather than naively relying on the image processing front end are demonstrated. © 2011 Wiley Periodicals, Inc.
Surface modification of titanium by using plasma‐induced graft‐polymerization
Authors: Chen Yashao , Sun Yu , Zhao Baoming , Wan Haiyan , Wu Di
Published: March 2011

Plasma‐induced graft‐polymerization (PIGP) method was utilized in this study to improve corrosion behavior and biocompatibility of titanium (Ti) surface. Bioactive molecule polyacrylamide (PAM) was immobilized onto Ti surface by introducing silanederivatized spacer arms as an intermediary for the covalent linkage. Ti was firstly activated by O2 plasma, and oxygen‐containing groups were introduced on its surface consequently. The intermediary mercapto silane spacer molecules were then covalently linked to the oxidated surface, followed by the covalent binding of PAM and the sulfhydryl‐terminal groups via PIGP. Surface analyses following modification process included water contact angles (CA), SEM, attenuated total reflection‐Fourier transform infrared spectroscopy (ATR‐FTIR), XPS and atomic force microscope (AFM). The results revealed the effectiveness of this method on immobilizing PAM to Ti surface, and the hydrophilicity of modified surface improved remarkably. In addition, potentiodynamic polarization and cellular proliferation tests were implemented to validate the enhanced corrosion‐resistance and biocompatibility of modified Ti surface, respectively. Copyright © 2011 John Wiley & Sons, Ltd.
The bridge over the ”La Fontaine” ravine, Réunion Island
Authors: Cremer Jean‐Marie , Del Forno Jean‐Yves , Klein Jean‐François.
Published: March 2011

This article deals with the design and construction of a bridge on Réunion Island. Its design results from a close cooperation between architect, landscape designer and engineers. It concerns a steel arch bridge with an unusual slenderness ratio of 1:7.5 guided by geotechnics, accessibility to the excavations and environmental and aesthetic considerations. Detailed studies of the wind (numerical calculation of the wind, wind tunnel studies, calculations with turbulent wind) allowed cyclone conditions to be taken into account in the design for top speeds, which can reach nearly 300 km/h. The structure was built using the cantilever method thanks to the addition of diagonals and temporary anchoring tie beams allowing a transitory lattice‐type operation.
Design of an electrified double‐track railway swing bridge in Malaysia
Authors: Patsch Armin , Humpf Karl , Kumar Sashi
Published: March 2011

A new swing bridge for an electrified double‐track railway has been proposed in Malaysia to replace an existing 40‐year‐old single‐track swing bridge. The proposed swing bridge has two equal cantilevers each 45 m long and features a steel ”sail” on both sides as the main longitudinal structural element. The 9.1 m wide bridge deck is a composite design — steel structure with concrete slab. The swing span will be powered by means of an electrohydraulic drive situated in the centre pier and slews over the centre bearing located below the centre pivot shaft.
Two high‐speed railway stations in Spain: from concept to details
Authors: Bernabeu Jorge
Published: March 2011

Stations for high‐speed rail travel are an important example of current trends in architecture and its relationship with structural engineering. This paper presents two Spanish examples where concept and detailed design can be highlighted as key elements of the structure. Tarragona‐Reus Station is a through station situated in a rural area. Its structure creates a roof topography that constitutes a landmark for the area. Rectangular hollow sections (RHS) are used to create planar Warren trusses that make up the triangular base around which the building is formed. Valencia station is a terminus in an urban location, with a provisional design based on a modular structure concept. The main loadbearing modules, with plate box sections, go beyond their construction purpose to act as a structural coffered ceiling and the visual representation of the station.
Optimization of stiffened plates for steel bridges based on Eurocode 3 Part 1‐5 using genetic algorithms
Authors: Mensinger Martin , Ndogmo Joseph , Parra Ricardo
Published: March 2011

Bridges are an important part of any country’s infrastructure. Welded stiffened plates are widely used as box girders for bridges. This article presents a design optimization problem for a single steel box with stiffeners on webs. The design is intended to be formulated based only on the current version of Eurocode 3 Part 1‐5 ”Plated structural elements”. Eurocode 3 will definitely be introduced in all the Member States of the European Union. This optimization resource represents an engineering compromise, not only for society, but also for avoiding negative impacts on the environment.
Athens Heart Shopping Mall Piraeus Street 180, Athens (GR), Job Report
Authors: Stimpfle Bernd
Published: March 2011

Temporary covered areas in Greece are seen as an open space, and so allow a higher usage of the land. The goal during the design was to find a light roof with direct view to the blue sky. The solution is a north light roof with highly translucent membrane panels and with a transparent cladding on the north side of the parallel steel girders to allow the direct view, and the entrance of the cool northern light.
Human Mesenchymal Stem Cells Reprogram Adult Cardiomyocytes Toward a Progenitor-Like State Through Partial Cell Fusion and Mitochondria Transfer
Authors: Acquistapace Adrien , Bru Thierry , Lesault Pierre-François , Figeac Florence , Coudert Amélie E. , le Coz Olivier , Christov Christo , Baudin Xavier , Auber Fréderic , Yiou René , Dubois-Randé Jean-Luc , Rodriguez Anne-Marie
Published: March 2011

Because stem cells are often found to improve repair tissue including heart without evidence of engraftment or differentiation, mechanisms underlying wound healing are still elusive. Several studies have reported that stem cells can fuse with cardiomyocytes either by permanent or partial cell fusion processes. However, the respective physiological impact of these two processes remains unknown in part because of the lack of knowledge of the resulting hybrid cells. To further characterize cell fusion, we cocultured mouse fully differentiated cardiomyocytes with human multipotent adipose-derived stem (hMADS) cells as a model of adult stem cells. We found that heterologous cell fusion promoted cardiomyocyte reprogramming back to a progenitor-like state. The resulting hybrid cells expressed early cardiac commitment and proliferation markers such as GATA-4, myocyte enhancer factor 2C, Nkx2.5, and Ki67 and exhibited a mouse genotype. Interestingly, human bone marrow-derived stem cells shared similar reprogramming properties than hMADS cells but not human fibroblasts, which suggests that these features might be common to multipotent cells. Furthermore, cardiac hybrid cells were preferentially generated by partial rather than permanent cell fusion and that intercellular structures composed of f-actin and microtubule filaments were involved in the process. Finally, we showed that stem cell mitochondria were transferred into cardiomyocytes, persisted in hybrids and were required for somatic cell reprogramming. In conclusion, by providing new insights into previously reported cell fusion processes, our data might contribute to a better understanding of stem cell-mediated regenerative mechanisms and thus, the development of more efficient stem cell-based heart therapies.
RCOR2 Is a Subunit of the LSD1 Complex That Regulates ESC Property and Substitutes for SOX2 in Reprogramming Somatic Cells to Pluripotency
Authors: Yang Peng , Wang Yixuan , Chen Jiayu , Li Hong , Kang Lan , Zhang Yu , Chen She , Zhu Bing , Gao Shaorong
Published: March 2011

Histone demethylase LSD1 can form complex with different Rcor family corepressors in different cell types. It remains unknown if cell-specific Rcor proteins function specifically in distinct cell types. Here, we report that Rcor2 is predominantly expressed in ESCs and forms a complex with LSD1 and facilitates its nucleosomal demethylation activity. Knockdown of Rcor2 in ESCs inhibited ESC proliferation and severely impaired the pluripotency. Moreover, knockdown of Rcor2 greatly impaired the formation of induced pluripotent stem (iPS) cells. In contrast, ectopic expression of Rcor2 in somatic cells together with Oct4, Sox2, and Klf4 promoted the formation of iPS cells. Most interestingly, ectopic expression of Rcor2 in both mouse and human somatic cells effectively substituted the requirement for exogenous Sox2 expression in somatic cell reprogramming.
Analysis of optimal spinning reserve procurement with demand response resources under social cost minimization
Authors: Behrangrad Mahdi , Sugihara Hideharu , Funaki Tsuyoshi
Published: March 2011

This paper evaluates the effect of demand response (DR) resources that are utilized in the reserve market using an optimal probabilistic mixed integer programming (MIP)‐based spinning reserve scheduling method. In order to analyze the DR utilization effect from a theoric point of view, the objective of the adopted framwork is social cost minimization. To be consistent with the increasing reliability requirements of loads and considering increasing uncertainity in the generation side because of penetration of intermitent renewable resources, both single and double outage contingencies are considered. Furthremore, for reduction of the computational burden, a two‐level optimization method is developed. Roy‐Bilinton test system (RBTS) is used in numerical simulations and the results are presented. The numerical results show that increase in the uncertainty at supply side resources, increases the need for the DR resources. The numerical results also show the effectiveness of the developed optimization method in reducing the computational time. © 2011 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.
Nonholonomic system control via particle swarm optimization of a neural‐aided direct gradient descent control
Authors: Duong Sam Chau , Kinjo Hiroshi , Uezato Eiho , Yamamoto Tetsuhiko
Published: March 2011

It is well known that the class of nonholonomic systems cannot be asymptotically stabilized by continuous static state feedback controls. It has been reported that the so‐called direct gradient descent control (DGDC) is able to stabilize nonholonomic systems. This article attempts to improve the performance of the DGDC by using neural network (NN) and particle swarm optimization (PSO). A control method is proposed by embedding an NN into the control law derived by the original DGDC. PSO is employed in order to search globally the parameters of the controller without requiring a redesign process of the parameters. To verify the method, the control problems of two typical nonholonomic systems, one being a wheeled mobile robot and the other a rotary crane system, are considered under constraints applied to the systems. Comparative performance tests are carried out, showing that the proposed approach outperforms the original method and a neurocontroller. Also, simulations show that the proposed method is able to control the systems effectively under the given constraints without the need of the redesign process. © 2011 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.
Four‐segment oscillator circuit for piezoelectric sensing devices
Authors: Satoh Tomio , Izyan Ruslan Ruzaini , Katou Yousuke , Marumo Masahide , Akitsu Tetsuya
Published: March 2011

Novel circuit design is proposed for a low‐frequency quartz crystal oscillator circuit that consists of four segments. The characteristics of the negative resistance in a low‐frequency Complementary Metal Oxide Semiconductor (CMOS)‐inverter quartz oscillator were reviewed for the two modes of SC (stress‐compensated) cut mode and the overtone of low‐frequency mode; separation of two modes and suppression of overtone oscillation were demonstrated successfully. Experimental results and an estimate of the absolute value of the negative resistance are presented for the four‐segment oscillator circuit and the conventional Colpitts circuit and two new types of oscillator circuits. © 2011 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.
An FPGA implementation of hard‐wired sequence control system based on PLC software
Authors: Ichikawa Shuichi , Akinaka Masanori , Hata Hisashi , Ikeda Ryo , Yamamoto Hiroshi
Published: March 2011

Although a programmable logic controller (PLC) has been widely adopted for the sequence control of industrial machinery, its performance does not always satisfy the recent requirements in large and highly responsive systems. With the state‐of‐the‐art field programmable gate array (FPGA) technology, it is possible to implement a control program with hard‐wired logic for higher response and reduced implementation cost/space. This approach is also worthwhile for transmigration of legacy PLC software into forthcoming FPGA‐based control hardware. This study presents a systematic method to implement a hard‐wired sequence control from PLC software. PLC instructions are converted into VHDL codes, and then implemented as logic circuit with various peripheral functions. Productive PLC programs were examined with Mitsubishi Electric FX2N PLC and Altera Stratix II FPGA, and were shown to fit into a common FPGA chip. A straightforward Sequential design was estimated to be 184 times faster than PLC, while a performance‐oriented Flat design was estimated to be 44 times faster than Sequential design (i.e., 8050 times faster than PLC). A practical perfect layer winder system was actually built and successfully operated with our FPGA control board, whose logic design was implemented with our tools. © 2011 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.
Andrews curves
Authors: Moustafa Rida E.
Published: March 2011

Andrews curves are examples of the space transformed visualization (STV) techniques for visualizing multivariate data, which represent k‐dimensional data points by a profile line (or curve) in two‐ or three‐dimensional space using orthogonal basis functions. Andrews curves are based on Fourier series where the coefficients are the observation's values. One advantage of the plot is based on the Parseval's identity (energy norm), which indicates that the information through transformation from the data space into the parameter space is preserved, and information that can be deduced in the hyperdimensional original space can be easily deduced in the two‐dimensional parameter space. This duality empowers the discovery of correlated records, clusters and outliers based on the curve's intersections, gaps and isolations, respectively. This article focuses on STV, in general, Andrews curves visualizations, in particular, and the effective use of these methods in the exploration of clusters, classes, and outliers. WIREs Comp Stat 2011 3 373–382 DOI: 10.1002/wics.160

This article is categorized under:

Statistical and Graphical Methods of Data Analysis > Statistical Graphics and Visualization