bluuebunny/crossref_metadata_2025_split huggingface dataset:
Electrospun aligned PHBV/collagen nanofibers as substrates for nerve tissue engineering
Authors: Prabhakaran Molamma P. , Vatankhah Elham , Ramakrishna Seeram 
Published: April 2013

ABSTRACTNerve regeneration following the injury of nerve tissue remains a major issue in the therapeutic medical field. Various bio‐mimetic strategies are employed to direct the nerve growth in vitro, among which the chemical and topographical cues elicited by the scaffolds are crucial parameters that is primarily responsible for the axon growth and neurite extension involved in nerve regeneration. We carried out electrospinning for the first time, to fabricate both random and aligned nanofibers of Poly(3‐hydroxybutyrate‐co‐3‐hydroxyvalerate; PHBV) and composite PHBV/collagen nanofibers with fiber diameters in the range of 386–472 nm and 205–266 nm, respectively. To evaluate the potential of electrospun aligned nanofibers of PHBV and composite scaffolds as a substrate for nerve regeneration, we cultured nerve cells (PC12) and studied the biocompatibility effect along with neurite extension by immunostaining studies. Cell proliferation assays showed 40.01% and 5.48% higher proliferation of nerve cells on aligned PHBV/Coll50:50 nanofibers compared to cell proliferation on aligned PHBV and PHBV/Col75:25 nanofibers, respectively. Aligned nanofibers of PHBV/Coll provided contact guidance to direct the orientation of nerve cells along the direction of the fibers, thus endowing elongated cell morphology, with bi‐polar neurite extensions required for nerve regeneration. Results showed that aligned PHBV/Col nanofibers are promising substrates than the random PHBV/Col nanofibers for application as bioengineered grafts for nerve tissue regeneration. Biotechnol. Bioeng. 2013;110: 2775–2784. © 2013 Wiley Periodicals, Inc.
A Study of Commercial Nanoparticulate γ‐Al2O3 Catalyst Supports
Authors: Rozita Yahaya , Brydson Rik , Comyn Tim P. , Scott Andrew J. , Hammond Chris , Brown Andy , Chauruka Sandra , Hassanpour Ali , Young Neil P. , Kirkland Angus I. , Sawada Hidetaka , Smith Ron I. 
Published: April 2013

AbstractThis study investigates a range of commercially available γ‐Al2O3 powders by using a combination of integrated experimental techniques. These included general measurements of powder properties by using helium density, BET surface area, and scanning electron microscopy (SEM) analyses. In addition, dynamic light scattering and zeta potential measurements were used to investigate nanoparticle dispersions. Bulk crystal structures were analysed by using comparative X‐ray and neutron powder diffraction (XRD and NPD) analyses. Conventional transmission electron microscopy (TEM) was used to determine particle morphology, particle size, composition, and structure. Aberration‐corrected TEM was used to investigate the crystallinity of nanoparticles including the existence of any surface reconstruction on commonly observed facetted, cubeoctahedral γ‐Al2O3 nanoparticles. From the observation of peak splittings in diffraction data, we favour a description of the γ‐Al2O3 structure based on a distortion of the conventionally accepted face‐centred cubic (Fd$\bar 3$m) structure into a tetragonal I41/amd structure. Distinct differences between TEM, XRD, and NPD data indicate the presence of some cation disorder within a rigid close‐packed oxygen framework. The Rietveld refinement of the NPD data suggests a high level of microstrain of 1.2 %. An improvement to the model is achieved by reducing the aluminium content in the unit cell, which is commensurate with the migration of aluminium ions to the surface and some degree of nonstoichiometry in the particle core. Aberration‐corrected TEM imaging and exit wave reconstruction confirm previous evidence for the presence of enhanced surface contrast at {1 1 1} surface facets, which we associate with the presence of excess cation termination. In addition, these {1 1 1} facets are observed to be heavily stepped. These results may have important implications for the thermal stability of metal catalyst nanoparticles on these high‐surface area supports; the migration of aluminium ions to the surface provides clear evidence of why these materials perform so well as catalyst supports.
Modeling of Multistage Bubble Column Reactors for Oxidation Reaction
Authors: Behin J. , Shojaeimehr T. 
Published: April 2013

AbstractIn this work, a mathematical model based on axial dispersion has been suggested to simulate the behavior of a multistage bubble column reactor. A six‐stage pilot‐scale reactor with an inner diameter of 0.35 m and a height of 12 m was used for hydrogen peroxide production through the direct oxidation of isopropyl alcohol at isothermal condition. Steady‐state and dynamic simulations were performed to predict the concentration of all the reactants in gas and liquid phases. It was observed that for steady state‐conditions the simulation results were consistent with the experimental results. Dynamic models involving liquid back‐mixing can be used for the simulation of start‐up, shut‐down or transition operations in this kind of a rector.
Computational Fluid Dynamics Modeling of Gas‐Liquid Two‐Phase Flow around a Spherical Particle
Authors: Du W. , Feng D. , Xu J. , Wei W. 
Published: April 2013

AbstractMicroscale studies, which can provide basic information for meso‐ and macroscale studies, are essential for the realization of flow characteristics of a packed bed. In the present study, the effects of gas velocity, liquid velocity, liquid‐solid contact angle, and liquid viscosity on the flow behavior were parametrically investigated for gas‐liquid two‐phase flow around a spherical particle, using computational fluid dynamics (CFD) methodology in combination with the volume‐of‐fluid (VOF) model. The VOF model was first validated and proved to be in good agreement with the experimental data. The simulation results show that the film thickness decreases with increasing gas velocity. This trend is more obvious with increasing operating pressure. With increasing liquid velocity, the film thickness tends to be uniform on the particle surface. The flow regime can change from film flow to transition flow to bubble flow with increasing contact angle. In addition, only at relatively high values does the liquid viscosity affect the residence time of the liquid on the particle surface.
Material Advancements in Fabrication of Mixed‐Matrix Membranes
Authors: Nasir R. , Mukhtar H. , Man Z. , Mohshim D. F. 
Published: April 2013

AbstractThe mixed‐matrix membrane (MMM) is a new membrane material for gas separation and plays a vital role for the advancement of current membrane‐based separation technology. Blending between inorganic fillers like carbon molecular sieves, zeolite, metal oxides, silica and silica nanoparticles, carbon nanotubes, zeolitic imidazolate framework, metal organic framework, and glassy and rubbery polymers etc. is possible. Due to mechanical, thermal, and chemical stability, these membranes achieve high permeability and selectivity as compared to pure polymeric materials. Despite of these advantages, the MMM performances are still below industrial expectations because of membrane defects and related processing problems as well as the nonuniform dispersion of fillers in MMMs. Material selection for organic and inorganic phases, preparation techniques, material advancements, and performance of MMMs are discussed. Issues and challenges faced during MMM synthesis as well as problem solutions are highlighted.
Silica/Silicone Nanofilament Hybrid Coatings with Almost Perfect Superhydrophobicity
Authors: Zhang Junping , Seeger Stefan 
Published: April 2013

AbstractA facile method for the preparation of silica/silicone nanofilament hybrid coatings with almost perfect superhydrophobicity (contact angle=179.8° and sliding angle=1.3°) is presented. The coatings are obtained by dip‐coating of silica nanoparticles, followed by chemical vapor deposition of silicone nanofilaments. Predominant growth of silicone nanofilaments onto aggregated silica nanoparticles generates a two‐tier structure. The effect of silica nanoparticle size on the growth of silicone nanofilaments, along with their anti‐wetting properties and transparency are investigated in detail. Surface roughness and anti‐wetting properties can be simply regulated by controlling the size of silica nanoparticles.
Glucose Dehydration to 5‐Hydroxymethylfurfural in a Biphasic System over Solid Acid Foams
Authors: Ordomsky Vitaly V. , van der Schaaf John , Schouten Jaap C. , Nijhuis T. Alexander 
Published: April 2013

AbstractA solid acid foam‐structured catalyst based on a binderless zirconium phosphate (ZrPO) coating on aluminum foam was prepared. The catalyst layer was obtained by performing a multiple washcoating procedure of ZrPO slurry on the anodized aluminum foam. The effect of the pretreatment of ZrPO, the concentration of the slurry, and the amount of coating on the properties of the foam was studied. The catalytic properties of the prepared foams have been evaluated in the dehydration of glucose to 5‐hydroxymethylfurfural (HMF) in a biphasic reactor. The catalytic behavior of ZrPO foam‐based catalysts was studied in a rotating foam reactor and compared with that of bulk ZrPO. The effect of a silylation procedure on the selectivity of the process was shown over bulk and foam catalysts. This treatment resulted in a higher selectivity due to the deactivation of unselective Lewis acid sites. Addition of methylisobutylketone leads to extraction of HMF from the aqueous phase and stabilization of the selectivity to HMF over bulk ZrPO. A more intensive contact of the foam with the aqueous and organic phases leads to an increase in the selectivity and resistance to deactivation of the foam in comparison with a bulk catalyst.
New SRAM design using body bias technique for low‐power and high‐speed applications
Authors: Faraji Rasoul , Naji Hamid Reza , Rahimi‐Nezhad Majid , Arabnejhad Mohammad 
Published: April 2013

ABSTRACTIn this paper, a new SRAM cell with body‐bias actively controlled by a control circuit and word line is introduced to realize low‐power and high‐speed applications. The cell uses two word lines, which vary between positive and negative voltage levels to control the body bias of cell's transistors. In this design, using a peripheral control circuit with the least possible number of transistors, the access time is decreased and also a trade‐off between static and dynamic power consumption is provided. Compared to a conventional SRAM cell, the proposed cell reduces the static power consumption by 82% and improves the read performance by 40% and the write performance by 27%. Copyright © 2013 John Wiley & Sons, Ltd.
A meshless finite point method for three‐dimensional analysis of compressible flow problems involving moving boundaries and adaptivity
Authors: Ortega Enrique , Oñate Eugenio , Idelsohn Sergio , Flores Roberto 
Published: April 2013

SUMMARYA finite point method for solving compressible flow problems involving moving boundaries and adaptivity is presented. The numerical methodology is based on an upwind‐biased discretization of the Euler equations, written in arbitrary Lagrangian–Eulerian form and integrated in time by means of a dual‐time steeping technique. In order to exploit the meshless potential of the method, a domain deformation approach based on the spring network analogy is implemented, andh‐adaptivity is also employed in the computations. Typical movable boundary problems in transonic flow regime are solved to assess the performance of the proposed technique. In addition, an application to a fluid–structure interaction problem involving static aeroelasticity illustrates the capability of the method to deal with practical engineering analyses. The computational cost and multi‐core performance of the proposed technique is also discussed through the examples provided. Copyright © 2013 John Wiley & Sons, Ltd.
Multi‐instrument observations from Svalbard of a traveling convection vortex, electromagnetic ion cyclotron wave burst, and proton precipitation associated with a bow shock instability
Authors: Engebretson M. J. , Yeoman T. K. , Oksavik K. , Søraas F. , Sigernes F. , Moen J. I. , Johnsen M. G. , Pilipenko V. A. , Posch J. L. , Lessard M. R. , Lavraud B. , Hartinger M. D. , Clausen L. B. N. , Raita T. , Stolle C. 
Published: April 2013

AbstractAn isolated burst of 0.35 Hz electromagnetic ion cyclotron (EMIC) waves was observed at four sites on Svalbard from 0947 to 0954 UT 2 January 2011, roughly 1 h after local noon. This burst was associated with one of a series of ~50 nT magnetic impulses observed at the northernmost stations of the IMAGE magnetometer array. Hankasalmi SuperDARN radar data showed a west‐to‐east (antisunward) propagating vortical ionospheric flow in a region of high spectral width ~ 1–2° north of Svalbard, confirming that this magnetic impulse was the signature of a traveling convection vortex. Ground‐based observations of the Hα line at Longyearbyen indicated proton precipitation at the same time as the EMIC wave burst, and NOAA‐19, which passed over the west coast of Svalbard between 0951 and 0952, observed a clear enhancement of ring current protons at the same latitude. Electron precipitation from this same satellite indicated that the EMIC burst was located on closed field lines, but near to the polar cap boundary. We believe these are the first simultaneous observations of EMIC waves and precipitating energetic protons so near to the boundary of the dayside magnetosphere. Although several spacecraft upstream of Earth observed a steady solar wind and predominantly radial interplanetary magnetic field orientation before and during this event, data from Geotail (near the morning bow shock) showed large reorientations of the interplanetary magnetic field and substantial decreases in ion density several minutes before it, and data from Cluster (near the afternoon bow shock) showed an outward excursion of the bow shock simultaneous with it. These upstream perturbations suggest that a spontaneous hot flow anomaly, a bow shock related instability, may have been responsible for triggering this event, but do not provide enough information to fully characterize that instability.
Identification of a subpopulation of nasopharyngeal carcinoma cells with cancer stem‐like cell properties by high aldehyde dehydrogenase activity
Authors: Yu Fenggang , Sim Adrian Chong Nyi , Li Chunwei , Li Yingying , Zhao Xuening , Wang De‐Yun , Loh Kwok Seng 
Published: April 2013

Objectives/HypothesisCancer stem cells have been reported as a new therapeutic target in many cancers, but their existence in nasopharyngeal carcinoma (NPC) is largely unknown. This study was conducted to determine cancer stem‐like cells in NPC cell line.Study DesignBasic science experimental study.MethodsAldehyde dehydrogenase (ALDH) activity, a putative functional marker for cancer stem cells, was assessed in Epstein‐Barr virus‐associated NPC cell line C666‐1 cells. The ability of cells with high and low ALDH activity to proliferate, resist therapy, and initiate tumor formation was compared.ResultsEnrichment of cancer stem‐like cells (with high ALDH activity) in C666‐1 was associated with a significantly greater ability to proliferate, be clonogenic, resist chemotherapy drugs and radiation, reconstitute a heterogeneous population, and express pluripotent markers. Furthermore, subcutaneous injection of these cells into immunodeficient nude mice resulted in a tendency of tumor formation at a higher rate as compared to cells with low ALDH activity.ConclusionsThese results provide evidence for the existence of cancer stem‐like cells in the NPC cell line C666‐1 cells. Laryngoscope, 123:1903–1911, 2013
Pelvic floor muscle training for prevention and treatment of urinary and fecal incontinence in antenatal and postnatal women: A short version Cochrane review
Authors: Boyle Rhianon , Hay‐Smith E. Jean C. , Cody June D. , Mørkved Siv 
Published: April 2013

AbstractBackgroundPelvic floor muscle training (PFMT) is commonly recommended during pregnancy and after birth both for prevention and the treatment of incontinence.ObjectivesEffect of pelvic floor muscle training compared to usual antenatal and postnatal care on incontinence.Search MethodsCochrane Incontinence Group Specialized Register; handsearching (searched February 7, 2012); the references of relevant articles.Selection CriteriaRandomized or quasi‐randomized controlled trials in pregnant or postnatal women having pelvic floor muscle training (PFMT) versus no PFMT or standard care.Data Collection and AnalysisDuplicate trial assessment, selection and data abstraction.ResultsTwenty‐two trials involving 8,485 women. Continent pregnant women (prevention) who had intensive antenatal PFMT were less likely to report urinary incontinence up to 6 months after delivery (risk ratio (RR) 0.71, 95% CI 0.54–0.95). Incontinent postnatal women (treatment) who received PFMT were less likely to report urinary incontinence 12 months after delivery (RR 0.60, 95% CI 0.35–1.03). In a mixed population (women with and without incontinence symptoms in late pregnancy or after delivery), PFMT did not reduce incontinence rates after delivery.Authors' ConclusionsFor women who are continent during pregnancy, PFMT may prevent urinary incontinence up to 6 months after delivery. The extent to which mixed prevention and treatment approaches to PFMT in the postnatal period are effective is less clear that is, offering advice on PFMT to all pregnant or postpartum women whether they have incontinence symptoms or not. There was little evidence about long‐term effects for either urinary or fecal incontinence. Neurourol. Urodynam. 33:269–276, 2014. © 2013 Wiley Periodicals, Inc.
Hybrid particle‐element method for an unstructured hexahedral mesh
Authors: Hernandez R.J. , Fahrenthold E.P. 
Published: April 2013

SUMMARYHamiltonian models of high‐velocity impact dynamics, based on a hybrid particle‐element kinematic scheme, offer an energy conserving description of general contact‐impact, perforation, and fragmentation physics with applications in a number of important engineering fields. Published work on these models has considered only a uniform finite element mesh, requiring curved surfaces and many target and projectile geometries to be represented in an approximate fashion. In recent research, the authors have developed a new formulation suitable for application to any solid model described by an unstructured hexahedral mesh. The formulation incorporates a new algorithm, which constructs an ellipsoidal particle discretization of the mass distribution described by a general hex mesh and a new density interpolation suitable for use with general ellipsoidal arrays whose particles vary in mass, shape, and spatial orientation. Application of the method in the simulation of high‐velocity impact problems shows good agreement with experiment, for both smoothly graded and deliberately distorted hexahedral meshes. Copyright © 2013 John Wiley & Sons, Ltd.
Cynophagia in the Púchov (Celtic) Culture Settlement at Liptovská Mara, Northern Slovakia
Authors: Chrószcz A. , Janeczek M. , Bielichová Z. , Gralak T. , Onar V. 
Published: April 2013

AbstractThis paper deals with the remains of butchered dogs from the La Tène and Early Roman sites in northern Slovakia. A large settlement revealed at Liptovská Mara was inhabited by the Celtic tribe of Cotini, representing the so‐called Púchov culture. The long‐term excavation of the site has yielded one of the largest collections from that time in Slovakia. During archaeozoological analysis, the skeletal remains of dogs were identified. Interestingly, a large portion of the specimens represent the cranial skeleton, and the majority of mandibles bear distinctive marks of butchery. On the basis of their placement and similar characteristics, the authors conclude that they resulted from tongue‐removal procedures. Moreover, their frequent occurrence clearly supports the idea of the use of dog flesh at the site. The authors argue that cynophagia occurred mainly for economic reasons; however, it might also have been part of the rituals documented in the sanctuary of Liptovská Mara. Copyright © 2013 John Wiley & Sons, Ltd.
Benefits and limitations of whole genome versus targeted approaches for noninvasive prenatal testing for fetal aneuploidies
Authors: Boon Elles M. J. , Faas Brigitte H. W. 
Published: April 2013

ABSTRACTThe goal to noninvasively detect fetal aneuploidies using circulating cell‐free fetal DNA in the maternal plasma seems to be achieved by the use of massively parallel sequencing (MPS). To date, different MPS approaches exist, all aiming to deliver reliable results in a cost effective manner. The most widely used approach is the whole genome MPS method, in which sequencing is performed on maternal plasma to determine the presence of a fetal trisomy. To reduce costs targeted approaches, only analyzing loci from the chromosome(s) of interest has been developed. This review summarizes the different MPS approaches, their benefits and limitations and discusses the implications for future noninvasive prenatal testing. © 2013 John Wiley & Sons, Ltd.
Copper–zinc thin films reactively co‐sputtered from a two‐component sectioned cathode
Authors: Burgstaller Wolfgang , Mardare Andrei Ionut , Hassel Achim Walter 
Published: April 2013

AbstractCu–Zn thin film oxide alloys have been fabricated by reactive co‐sputter deposition using a sectioned two‐component metallic target. A Cu–Zn compositional spread ranging from Cu–88 at.% Zn to Cu–1.3 at.% Zn defining a combinatorial library was identified. A thickness gradient with a maximum of 4.1 µm was found. The microstructure of the Cu–Zn oxide thin films was analyzed by SEM, finding three compositional zones with structural differences. XRD investigations have revealed different crystalline structures for each of the three zones. CuZn intermetallics and pure Cu‐phase were identified together with Cu2O and ZnO. For the first compositional zone XPS depth profiles have shown metallic phase segregation at the thin film/substrate interface. At Zn concentrations higher than 45 at.% Zn an increased tendency of ZnO formation was identified.
Temperature‐dependent ferroelectric dynamic hysteresis properties of modified PMN–PZT relaxor ceramics
Authors: Du Gang , Liang Ruihong , Wang Li , Li Kui , Zhang Wenbin , Wang Genshui , Dong Xianlin 
Published: April 2013

AbstractTemperature‐dependent ferroelectric dynamic hysteresis properties of modified Pb(Mg1/3Nb2/3)O3–Pb(Zr,Ti)O3 (PMN–PZT) ceramics have been investigated in a wide range from 298 to 433 K. Interestingly, it was found that back‐switching polarization Pbc increased while the hysteresis area 〈A 〉, coercive field Ec, saturation polarization Ps, and remnant polarization Pr all decreased linearly with temperature below 398 K (close to the macro–micro domain transition temperature Tnr). A set of simple linear temperature scaling relations was established, which is different from the power‐law scaling relations for soft and hard PZT ceramics. At further increased temperature, double‐loop features appeared and the ferroelectric properties varied nonlinearly due to the reversible macro–micro domain transition in the T > Tnr region. (© 2013 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)