bluuebunny/crossref_metadata_2025_split huggingface dataset:
Expanding stability regions of explicit advective‐diffusive finite difference methods by Jacobi preconditioning
Authors: Rodrigue Garry , Wolitzer Donald 
Published: August 2005

AbstractExplicit time differencing methods for solving differential equations are advantageous in that they are easy to implement on a computer and are intrinsically very parallel. The disadvantage of explicit methods is the severe restrictions that are placed on stable time‐step intervals. Stability bounds for explicit time differencing methods on advective–diffusive problems are generally determined by the diffusive part of the problem. These bounds are very small and implicit methods are used instead. The linear systems arising from these implicit methods are generally solved by iterative methods. In this article we develop a methodology for increasing the stability bounds of standard explicit finite differencing methods by combining explicit methods, implicit methods, and iterative methods in a novel way to generate new time‐difference schemes, called preconditioned time‐difference methods. A Jacobi preconditioned time differencing method is defined and analyzed for both diffusion and advection–diffusion equations. Several computational examples of both linear and nonlinear advective‐diffusive problems are solved to demonstrate the accuracy and improved stability limits. © 1995 John Wiley & Sons, Inc.
A conservative semi‐Lagrangian method for multidimensional fluid dynamics applications
Authors: Scroggs J. S. , Semazzi F. H. M. 
Published: August 2005

AbstractWe describe a finite volume semi‐Lagrangian method for the numerical approximation of conservation laws arising in fluid‐dynamic applications. A discrete conservation relation is satisfied by using conservative interpolation for the material (or property) being conserved. The method was developed with a view to application in climate prediction. © 1995 John Wiley & Sons, Inc.
Solution domain decomposition with finite difference methods for partial differential equations
Authors: Nguyen Hoa D. , Paik Seungho 
Published: August 2005

AbstractThe Solution Domain Decomposition method of Nguyen and Paik [J. Sci. Comput. 4, 357 (1993)] originally developed in a pseudospectral context is extended for use with finite difference techniques to solve partial differential equations. The essential idea behind this method lies in an application of the superposition principle, which allows interactions between adjacent subdomains to be decoupled and the resulting equations to be solved in parallel. Several tests are performed to assess its accuracy and efficiency based on a model problem arising from thermal convection inside a fluid‐saturated porous cavity with heating from a side. The results reveal a well adaptation of the methodology into the framework of finite differences. © 1995 John Wiley & Sons, Inc.
Coupling of FEM and BEM for a nonlinear interface problem: The h–p version
Authors: Carstensen C. , Stephan E. P. 
Published: August 2005

AbstractThis article presents some numerical examples for coupling the finite element method (FEM) and the boundary element method (BEM) as analyzed in [11]. This coupling procedure combines the advantages of boundary elements (problems in unbounded regions) and of finite elements (nonlinear problems with inhomogeneous data). In [28], experimental rates of convergence for the h version are presented, where the accuracy of the Galerkin approximation is achieved by refining the mesh. In this article we treat the h–p version, combining an increase of the degree of the piecewise polynomials with a certain mesh refinement. In our model examples, we obtain theoretically and numerically exponential convergence, which indicates a great efficiency in particular if singularities appear. © 1995 John Wiley & Sons, Inc.
Expression of NOX1, a superoxide‐generating NADPH oxidase, in colon cancer and inflammatory bowel disease
Authors: Szanto I , Rubbia‐Brandt L , Kiss P , Steger K , Banfi B , Kovari E , Herrmann F , Hadengue A , Krause K‐H 
Published: August 2005

AbstractReactive oxygen species (ROS) are at the centre of many physiological and pathological processes. NOX1, a ROS‐producing NADPH oxidase, is highly expressed in the colon but its function in colonic physiology or pathology is still poorly understood. It has been suggested to play a role in host defence, but also in cell growth and possibly malignant transformation. In this study we characterized NOX1 expression in human colon samples derived from healthy control subjects and patients with colon cancer or inflammatory bowel disease (IBD). NOX1 mRNA expression was assessed by dot‐blot hybridization, real‐time PCR and in situ hybridization, using samples derived from surgical specimens from patients undergoing colon resection. In normal tissues, NOX1 expression was low in the ileum, intermediate in the right colon, and high in the left colon (p = 0.0056 right vs. left colon). NOX1 mRNA levels were not influenced by factors linked to colon tumourigenesis, such as age or sex. Moreover, there was no statistical difference in NOX1 expression between samples derived from adenomas, well differentiated or poorly differentiated colon adenocarcinomas. At a cellular level, NOX1 was highly expressed in colon epithelial cells, both within the crypts and on the luminal surface. In addition, a population of lymphocytes, particularly in the appendix, showed NOX1 expression. Lymphocytes in lesions of Crohn's disease and ulcerative colitis were also strongly positive for NOX1. In conclusion, NOX1 is an enzyme that is constitutively expressed in colon epithelium and is not associated with tumourigenesis. Its distribution in crypts and on the luminal surface, as well as its left‐to‐right gradient in the colon, suggests a role in host defence function. In addition to the known epithelial localization, we define lymphocytes as a novel site of NOX1 expression, where it may potentially be involved in the pathogenesis of inflammatory bowel diseases. Copyright © 2005 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.
Prenatal diagnosis in a family with X‐linked hydrocephalus
Authors: Panayi Maria , Gokhale David , Mansour Sahar , Elles Rob 
Published: August 2005

AbstractThe neural cell adhesion molecule L1 is a transmembrane glycoprotein belonging to the immunoglobulin superfamily of cell adhesion molecules (CAMs). Its expression is essential during embryonic development of the nervous system and it is involved in cognitive function and memory. Mutations in the L1CAM gene are responsible for four related L1 disorders; X‐linked hydrocephalus/HSAS (Hydrocephalus as a result of Stenosis of the Aqueduct of Sylvius), MASA (Mental retardation, Aphasia, Shuffling gait, and Adducted thumbs) syndrome, X‐linked complicated spastic paraplegia type I (SPG1) and X‐linked Agenesis of the Corpus Callosum (ACC). These four disorders represent a clinical spectrum that varies both between and within families. The main clinical features of this spectrum are Corpus callosum hypoplasia, mental Retardation, Adducted thumbs, Spastic paraplegia and Hydrocephalus (CRASH syndrome). Since there is no biochemically assayed disease marker, molecular analysis of the L1CAM gene is the only means of confirming a clinical diagnosis. Most L1CAM mutations reported to date are point mutations (missense, nonsense, splice site) and only a few patients with larger rearrangements have been documented. We have characterised a rare intragenic deletion of the L1CAM gene in a sample of DNA extracted from a chorionic villus biopsy (CVB) performed at 12 weeks' gestation. Copyright © 2005 John Wiley & Sons, Ltd.
The influence of maternal insulin‐dependent diabetes on fetal nuchal translucency thickness and first‐trimester maternal serum biochemical markers of aneuploidy
Authors: Spencer Kevin , Cicero Simona , Atzei Alessia , Otigbah Chineze , Nicolaides Kypros H. 
Published: August 2005

AbstractObjectiveTo evaluate the influence of maternal insulin dependent diabetes mellitus (IDDM) on maternal serum free β‐hCG, PAPP‐A and fetal nuchal translucency (NT), thickness at 11 to 13+6 weeks of gestation in a large cohort of women screened prospectively for chromosomal anomalies.MethodsInformation on maternal IDDM status, maternal serum biochemical marker levels and fetal NT were collected from the prenatal screening computer records in two first‐trimester screening centres. In total the control group included 33 301 pregnancies of which 16 366 had NT and maternal serum biochemistry results and 16 305 with NT only. The IDDM group included 195 pregnancies of which 79 had NT and maternal serum biochemistry results and 127 with NT only. The median maternal weight corrected free β‐hCG and PAPP‐A, expressed as multiple of the median (MoM), and fetal NT, expressed as delta values, in the IDDM and non‐IDDM groups were compared.ResultsThere were no significant differences between the IDDM and non‐IDDM groups in median maternal weight corrected free β‐hCG (IDDM 0.87 MoM, 95% Confidence Interval 0.75 to 1.16 MoM, non‐IDDM 1.00 MoM), median maternal weight corrected PAPP‐A (IDDM 1.02 MoM, 95% Confidence Interval 0.83 to 1.05 MoM, non‐IDDM 1.01 MoM), or mean delta NT (IDDM 0.0358 mm, non‐IDDM 0.0002 mm).ConclusionsIn pregnancies with maternal IDDM, first‐trimester screening for chromosomal defects does not require adjustments for the measured fetal NT. However, more data are required before the possible reduction in maternal serum free β‐hCG and the reduction of PAPP‐A suggested by the published world series can be considered sufficiently important to take into account in the calculation of risks for chromosomal defects. Copyright © 2005 John Wiley & Sons, Ltd.
A semi‐quantitative microarray method to detect fetal RNAs in maternal plasma
Authors: Ge Qinyu , Liu Quanjun , Bai Yunfei , Wen Tian , Lu Zuhong 
Published: August 2005

AbstractObjectivesTo set up a semi‐quantitative microarray method for the detection of fetal RNAs in maternal plasma.MethodsWe developed a semi‐quantitative microarray method for the detection of placental RNA in maternal plasma. Firstly, the selected fetal RNAs were linearly amplified from the maternal plasma and then fluorescently labeled as the target DNAs. Finally, the targets were hybridized and detected by capturing DNA probes on a microarray slide. Two genes of beta subunit of human chorionic gonadotrophin (β‐hCG) and zinc finger gene on the Y chromosome (ZFY) were assayed with the microarray, and beta actin gene was used as an internal standard. Eighty‐five pregnant women in the first trimester and the third trimester of gestation joined in this experiment, 14 of them also sampling in 36 h after delivery for the same assay. Real‐time quantitative PCR was performed for comparison.ResultsIt was found that the mRNA level of β‐hCG decreased with the increasing of gestation age, and it was much higher in the carriers of the female fetus than in the carriers of the male fetus in the first trimester of gestation, which was consistent with the real‐time quantitative PCR results. The results also reveal that delivery would result in the clearance of fetal mRNA in maternal plasma.ConclusionsThe results suggest that the semi‐quantitative microarray method has great potential as a high‐throughput assay in prenatal diagnosis and clinical laboratory. Copyright © 2005 John Wiley & Sons, Ltd.
The effect of compatibilization on the behavior of a polycarbonate/polymer liquid crystal blend
Authors: Singer Michelle , Simon George P. , Varley Russell , Nobile M. Rossella 
Published: August 2005

AbstractPolymer liquid crystalline materials (PLC) blended with engineering plastics (EP) have the potential to reduce viscosity and increase the modulus of the EP, particularly if the PLC is in a favorable fibrillar morphology. A major deficiency in these blends—as with many other immiscible polymeric systems—is poor failure properties. In this paper, polycarbonate (PC) and a rigid, all‐aromatic commercial PLC are blended and a third resin, a copolymer of methyl methacrylate and N‐methyl‐dimethyl‐glutarimide is included as a compatibilizing agent. Characterization of the binary and ternary blends is carried out using rheological, mechanical, morphological, and dynamic mechanical characterization techniques. Binary blends of PLC in a PC matrix result in an immiscible, nodular morphology with low failure stresses. The addition of the copolymeric compatibilizer—particularly one with reactive functionalities—is found to improve tensile strength and yield a fibrillar blend morphology. It is proposed that this may be due to the compatibilizer reducing interfacial tension and adhering to the blend phases, rather than by causing a major change in blend viscosity.
Polymers from renewable resources. VII: Thermal properties of the semi‐interpenetrating polymer networks composed of castor oil polyurethanes and cardanol‐furfural resin
Authors: Mishra D. K. , Mishra B. K. , Lenka S. , Nayak P. L. 
Published: August 2005

AbstractA number of semi‐interpenetrating polymer networks (semi‐IPNs) were synthesized by reacting polyurethanes (prepared from castor oil and various diisocyanates) and a phenolic resin (prepared from cardanol and furfural) The physico‐chemical properties of the semi‐IPNs have been investigated. The thermogravimetric analysis of polymers was followed using a computer analysis method for assigning the kinetic mechanism. Various kinetic equations have been used to evaluate the kinetic parameters. The suggested mechanism of degradation of the semi‐IPNs is based on the kinetic parameters.
Nonlinear behavior of linear low‐density polyethylene
Authors: Rand James L. , Henderson John K. , Grant Debora A. 
Published: August 2005

AbstractTo predict the response of polyethylene thin films subjected to stress for a long time, it is necessary to understand the influence of stress on either the relaxation modulus or creep compliance. Extensive testing has been conducted on 20‐micron‐thick samples of a particular linear low‐density polyethylene film at temperatures from 23°C to −50°C. When reduced to creep compliance and compared with results from dynamic mechanical analysis (DMA), the influence of nonlinearities in the response function is apparent. However, the use of a two‐step loading procedure has produced sufficient data to discriminate between the effect of stress on amplitude and time on the creep compliance. It has been found that a master curve of compliance generated by DMA equipment may be used in conjunction with certain nonlinear functions to accurately predict the response of the polyethylene. Perhaps of more importance is the observation that the principles of simple time‐temperature superposition, commonly used with linear viscoelastic characterization, are insufficient for use with polyethylene films at most stress levels of interest.
Studies on the modification of interphase/interfaces by use of plasma in certain polymer composite systems
Authors: Akovali Güneri , Dilsiz Nursel 
Published: August 2005

AbstractCalcium carbonate and carbon fiber surfaces were modified by use of a series of plasma polymers at different selected plasma conditions, and the effect of surface modification, mainly on the mechanical properties of composite systems prepared, was investigated. The matrices for the composite systems employed were polypropylene and epoxy, for the chalk and C fiber, respectively. Mechanical and thermal studies and scanning electron microscopy (SEM) pictures revealed that inclusion surfaces, being independent of their geometry and size, can be modified effectively by plasma. A polypropylene matrix with 30% modified chalk had better properties than composites with 10% unmodified chalk. Tensile strength and stress to failure values for single carbon fibers were found to be improved by plasma treatment. Surface‐treated carbon fibers yielded at composites with better interlaminar shear strength and flexural strengths.
On the role of electric forces in the processing of composites prepared with polymeric matrices
Authors: Yurkevich Oleg R. 
Published: August 2005

AbstractThermosetting and thermoplastic polymeric binders in the powder form and reinforcing carbon‐, glass‐, and organic fiber fillers were used to study the effects of electric forces on different stages of composites processing. Electric fields appear to uniformly distribute the powder binder across the filler surface as well as through its bulk. They favor stronger interaction of the components, leading to composites with better physical‐and‐mechanical performance properties. The optimal conditions provided for mixing of the components in an electrostatic field promote higher strength (by 1.5–1.8 times) and lower porosity (by 2–3 times) of carbon‐, and glass‐fiber reinforced plastics.
Conformation of polymer molecules at solid‐liquid interfaces by small‐angle neutron scattering
Authors: Forsman W. C. , Latshaw B. E. 
Published: August 2005

AbstractA wide variety of physical‐chemical phenomena depend on the behavior of the polymer at solid‐liquid interfaces. The feature that distinguishes such phenomena from their small‐molecule counterparts is the long‐chain structure of the polymer molecules. Just as in solution and the bulk, the conformational statistics of the polymer molecules in the interface is an important determinant of interfacial properties. Conformational statistics of interfacial polymer is expressed in terms a function called the polymer density profile ϕ(Z), which is just the volume fraction of polymer as a function of Z, the distance from the solid surface out into the continuum liquid. There is only one experimental technique that is purported to be able to determine polymer density profiles of polymers confined to the interface between finely divided substrate and dispersant, and that technique is small‐angle neutron scattering (SANS). In this paper we present a protocol for the analysis of SANS data on spherical particles with adsorbed polymer for the determination of ϕ(Z). We give an example for nearly‐monodisperse chains of poly(n‐butyl methacrylate) with a molecular weight of 45,000 tethered to silica spheres with a diameter of 2150 Å. The polymer density profile demonstrates a deep depletion layer next to the surface with a maximum in ϕ(Z) of about 0.7 at about Z = 40 Å. Our experimental ϕ(Z) is compared with various theoretical predictions.
Low‐density polyethylene modified by thermal polymerization of 4‐vinylpyridine and methyl methacrylate: Structural studies
Authors: De Barros Glaucione Gomes , Sales Maria José Araújo , De Britto Ana Regina Feitosa 
Published: August 2005

AbstractThe structures of low‐density polyethylene (LDPE) modified by in situ sorption and thermal polymerization of 4‐vinylpyridine (4VP) and of methyl methacrylate (MMA) were studied. The phase behavior of these materials was investigated by means of X‐ray diffraction, scanning electron microscopy (SEM), and by thermal measurements (DSC). The diffraction studies indicated that the polymerization occurs at the amorphous domains of the matrix, except for the case of 4VP (168.0%), in which polymerization at the crystalline domains of LDPE matrix was also observed. These materials showed at least two Tg values, indicating microphase separation. The morphology of LDPE‐P4VP was different from that of LDPE‐PMMA.
Comments and corrections on “crystallization during polymerization of diphenylsilylene by a chemical transport reaction”
Authors: Shu Hua‐Cheng , Wunderlich Bernhard 
Published: August 2005

AbstractNeedlelike crystals of a phenylsilicon compound synthesized on crystallization during polymerization in a transport reaction in a temperature gradient, which were thought earlier to be polymeric diphenylsilylene, are shown to be actually tetraphenylsilane. Similarly produced crystals of the germanium analog led, in contrast, to polydiphenylgermylene. An overall reaction scheme uniting both reactions is suggested.
Viscoelastic properties of ethyl acrylate ionomers. I. Stress relaxation
Authors: Eisenberg A. , Matsuura H. , Tsutsui T. 
Published: August 2005

AbstractEthyl acrylate ionomers were studied by stress relaxation. The results are compared with those for the styrene ionomers studied previously. The behaviour of the two systems is qualitatively similar, although significant quantitative differences exist. Specifically, the onset of thermorheological complexity is found here at 12–16 mole% of ions, while in styrene it is observed at ca. 6 mole%. Furthermore, the modulus‐temperature plots show great similarity if the present samples are compared with the styrenes containing about half as many ions. Other properties show similar trends. The increased dielectric constant of the acrylates is believed to be responsible for the observed differences in the two systems. The effect of a change in counterions was also studied to some extent. The onset of thermorheological complexity is seen to be qualitatively related to the size and charge of the cation.
Photoconductivity of poly(hexamethylene adipamide)
Authors: Guillaud G. , Rosenberg N. , Maitrot M. 
Published: August 2005

AbstractPhotocurrents induced by pulsed ultraviolet light in polyhexamethylene adipamide (nylon‐66) have been studied. Two transient photocurrents are observed for light wavelenghts shorter than 3000 Å;. The first one is weakly field and temperature dependent and has been ascribed to electron photoinjection. On the whole, the time dependence of the two photoresponses suggests the possible formation of a space charge in the material.
Coherent scattering law for dilute polymer solutions: Continued fraction formalism
Authors: John Myung S. , Fesciyan Sezar , Dahler John S. 
Published: August 2005

AbstractThe continued fraction formalism of Mori is adapted to study the coherent scattering law of dilute polymer solutions. Calculations are carried out for the Rouse chain to see the effects of the memory function. We find such effects to be significant.