bluuebunny/crossref_metadata_2025_split huggingface dataset:
Dexamethasone induces human spinal ligament derived cells toward osteogenic differentiation
Authors: Murata Hidenori , Tanaka Hiroshi , Taguchi Toshihiko , Shiigi Eiichi , Mizokami Hiroshi , Sugiyama Toshihiro , Kawai Shinya 
Published: May 2004

AbstractOssification of spinal ligament is characterized by heterotopic bone formation in the spinal ligaments that are normally composed of fibrous tissues. The pathogenesis of ossification of spinal ligament has been suggested to be associated with osteogenic differentiation of the spinal ligament cells. In order to address this hypothesis, cells derived from human spinal ligament were investigated for their osteogenic potential by the treatment of dexamethasone in vitro. Yellow ligaments were obtained from patients with spinal disorders except ossification of spinal ligament during surgery, and the adhering tissues were removed completely. Most of the ligament cells treated with vehicle exhibited a fibroblast‐like spindle shape, while the dexamethasone‐treated cells acquired a polygonal morphology. Growth of the ligament cells was suppressed by dexamethasone at a high concentration. Some of the vehicle treated‐cells were alkaline phosphatase‐positive, and dexamethasone increased the alkaline phosphatase‐positive cells and alkaline phosphatase activity in the cells. Northern blot analysis demonstrated that mRNAs expression of pro‐α1(I) collagen and alkaline phosphatase were promoted by dexamethasone. Analysis by reverse transcription‐polymerase chain reaction showed that expression of osteocalcin mRNA was detected in the dexamethasone‐treated cells but not in the vehicle‐treated cells, and dexamethasone‐induced osteocalcin mRNA expression was promoted by 1,25‐dihydroxyvitamin D3. Finally, mineralization of extracellular matrix in the cells was induced by the presence of dexamethasone and 1,25‐dihydroxyvitamin D3. These results suggest for the first time that dexamethasone has a possible involvement in the osteoblastic differentiation of human spinal ligament cells. © 2004 Wiley‐Liss, Inc.
Regulation of gene expression associated with acute experimental autoimmune encephalomyelitis by Lovastatin
Authors: Paintlia Ajaib Singh , Paintlia Manjeet Kaur , Singh Avtar Kaur , Stanislaus Romesh , Gilg Anne Genevieve , Barbosa Ernest , Singh Inderjit 
Published: May 2004

AbstractThe attenuation of experimental autoimmune encephalomyelitis (EAE) by Lovastatin (LOV) has now been well established. The present study was designed to explore the global effect of LOV treatment on expression of immune‐related genes in lumbar spinal cord (LSC) during acute EAE by using Affymetrix DNA microarrays. LOV treatment demonstrated the limited infiltration of inflammatory cells into the LSC, and microarray analysis further validated those interpretations by demonstrating relatively less alteration in expression of immune response genes in LOV‐treated EAE rats on peak clinical day and recovery vs. untreated EAE counterparts. There was significant change in expression of about 158 immune‐related genes (including 127 genes reported earlier) in LOV‐treated vs. untreated EAE (>1.5 or <‐1.5 fold change; P ≤ .05), of which 140 genes were suppressed and only 18 genes were up‐regulated. These altered genes encode for leukocyte‐specific markers and receptors, histocompatibility complex, cytokines/receptors, chemokines/receptors, adhesion molecules, components of the complement cascade, cellular activation, and transcription factors and signal transduction‐related molecules. Interestingly, TH2 phenotype cytokines such as interleukin‐4, interleukin‐10, and transforming growth factor‐β1 and transcription factors such as peroxisome proliferator‐activated receptor (PPAR)‐γ were up‐regulated in LSC by LOV treatment as further revealed by real‐time PCR and immunoblotting. These findings indicate that PPARs may be mediating the antiinflammatory and immunomodulatory effects of LOV. Together, these findings provide new insight into the molecular events associated with the protection provided by statins during treatment of demyelinating diseases such as multiple sclerosis. © 2004 Wiley‐Liss, Inc.
Combination effect of sodium lactate and irradiation on color, lactic acid bacteria, lipid oxidation and residual nitrite in Chinese sausages during storage at 25 °C
Authors: Kuo James CC , Chen Hui‐Lien 
Published: May 2004

AbstractChinese sausages, with the addition of 0 or 2% sodium lactate, were vacuum‐packaged and stored overnight at 4°C. Refrigerated sausages were gamma‐irradiated at 0, 3 or 5 kGy absorbed dose. Meat samples were stored at 25°C for up to 30 days. Color, lactic acid bacteria, pH, lipid oxidation and residual nitrite were determined during storage. Irradiated samples were reduced in redness as a result of irradiation and storage time. Irradiation at 5 kGy alone or in combination with 2% sodium lactate and irradiation at 3 kGy could completely inhibit lactic acid bacterial growth. Thiobarbituric acid reactive substances (TBARS) values decreased as the pH values of samples increased. Sodium lactate decreased TBARS values of all samples and protected against a decrease of residual nitrite during storage. Irradiation reduced residual nitrite in Chinese sausage, and residual nitrite decreased with increased time. Copyright © 2004 Society of Chemical Industry
Synthesis and Characterization of Poly(N‐vinylimidazole‐co‐acrylonitrile) and Determination of Monomer Reactivity Ratios
Authors: Pekel Nursel , Rzaev Zakir M. O. , Güven Olgun 
Published: May 2004

AbstractSummary: Radical‐initiated solution copolymerization of N‐vinylimidazole (VIM) and acrylonitrile (AN) was carried out with 2,2′‐azobisisobutyronitrile (AIBN) as an initiator in benzene at 70 °C in nitrogen atmosphere. The structure and composition of synthesized copolymers for a wide range of monomer feeds were determined by FTIR, 1H and 13C NMR spectroscopy with the aid of recorded analytical absorption bands for VIM (667 cm−1, CN of imidazole ring) and AN (2 242 cm−1, CN group), as well as by using the areas of proton and carbon atom signals from corresponding functional groups of monomer units. Monomer reactivity ratios for VIM (M1)‐AN (M2) pair were determined by nonlinear regression (NLR), Kelen–Tüdös (KT) and Fineman–Ross (FR) methods. They were found to be r1 = 0.24 and r2 = 0.15 for the NLR method, r1 = 0.22 and r2 = 0.094 for the KT method, and r1 = 0.24 and r2 = 0.12 for the FR method, respectively. The relatively high activity observed of VIM growing macroradical and the results of FTIR and 1H NMR structural analysis of copolymers suggest the formation of complexed linkages between monomers and growing radicals in chain propagation reactions. Similar complexation between monomer–comonomer units in the structure of formed macromolecules showed an increase in isotactic triad fractions in the copolymer.Complex formation between the imidazole ring and nitrile group in both the monomer mixture and chain growing reactions.imageComplex formation between the imidazole ring and nitrile group in both the monomer mixture and chain growing reactions.
Polymerization of Propene and 1,3‐Butadiene with Vanadyl(V) Monoamidinate Precatalysts and MAO or Dialkylaluminum Chloride Cocatalysts
Authors: Liguori Dario , Centore Roberto , Csok Zsolt , Tuzi Angela 
Published: May 2004

AbstractSummary: Two new vanadyl(V) amidinates have been synthesized and characterized by single crystal X‐ray diffraction and 1H NMR. The complexes are dimeric with Cl bridges and monodentate coordination of the amidinate ligand to pseudooctahedral vanadium. In the presence of organometallic compounds of aluminum, these vanadyl complexes promote polymerization of propene and 1,3‐butadiene.image
PLP‐SEC Study into the Free‐Radical Propagation Rate Coefficients of Partially and Fully Ionized Acrylic Acid in Aqueous Solution
Authors: Lacík Igor , Beuermann Sabine , Buback Michael 
Published: May 2004

AbstractSummary: Propagation rate coefficients, kp, for acrylic acid (AA) polymerization at 6 °C in aqueous solution were measured via pulsed laser polymerization (PLP) with the degree of ionization, α, varied over the entire range between 0 and 1. These measurements were carried out in conjunction with aqueous‐phase size‐exclusion chromatography (SEC). Strictly speaking, the reported kp's are “apparent” propagation rate coefficients deduced from the PLP‐SEC data under the assumption that the local monomer concentration at the radical site is identical to overall monomer concentration. At an AA concentration of 0.69 mol · L−1, the apparent kp decreases from 111 000 L · mol−1 · s−1 at α = 0 to 13 000 L · mol−1 · s−1 at α = 1.0. The significant lowering of kp with higher α is attributed to the repulsion between both monomer molecules and macroradicals becoming negatively charged. Addition of up to 10 mol‐% (with respect to AA) sodium hydroxide to the fully ionized aqueous AA solution leads to an enhancement of kp up to 57 000 L · mol−1 · s−1.Dependence of apparent kp values on the degree of ionization of acrylic acid (a) and on pH (b) for aqueous polymerizations of acrylic acid.imageDependence of apparent kp values on the degree of ionization of acrylic acid (a) and on pH (b) for aqueous polymerizations of acrylic acid.
On a resolvent estimate of the Stokes equation with Neumann–Dirichlet‐type boundary condition on an infinite layer
Authors: Abe Takayuki 
Published: May 2004

AbstractThis paper is concerned with the standard Lp estimate of solutions to the resolvent problem for the Stokes operator on an infinite layer with ‘Neumann–Dirichlet‐type’ boundary condition. Copyright © 2004 John Wiley & Sons, Ltd.
Optimal boundary control of glass cooling processes
Authors: Pinnau René , Thömmes Guido 
Published: May 2004

AbstractIn this paper, an optimal control problem for glass cooling processes is studied. We model glass cooling using the SP1 approximations to the radiative heat transfer equations. The control variable is the temperature at the boundary of the domain. This results in a boundary control problem for a parabolic/elliptic system which is treated by a constrained optimization approach. We consider several cost functionals of tracking‐type and formally derive the first‐order optimality system. Several numerical methods based on the adjoint variables are investigated. We present results of numerical simulations illustrating the feasibility and performance of the different approaches. Copyright © 2004 John Wiley & Sons, Ltd.
Dynamic boundary stabilization of a Reissner–Mindlin plate with Timoshenko beam
Authors: Dalsen Marié Grobbelaar‐Van 
Published: May 2004

AbstractThis paper is concerned with well‐posedness results for a mathematical model for the transversal vibrations of a two‐dimensional hybrid elastic structure consisting of a rectangular Reissner–Mindlin plate with a Timoshenko beam attached to its free edge. The model incorporates linear dynamic feedback controls along the interface between the plate and the beam. Classical semigroup methods are employed to show the unique solvability of the coupled initial‐boundary‐value problem. We also show that the energy associated with the system exhibits the property of strong stability. Copyright © 2004 John Wiley & Sons, Ltd.
A direct method for solving an anisotropic mean curvature flow of plane curves with an external force
Authors: Mikula Karol , S̆evc̆ovic̆ Daniel 
Published: May 2004

AbstractA new method for solution of the evolution of plane curves satisfying the geometric equation v=β(x,k,ν), where v is the normal velocity, k and ν are the curvature and tangential angle of a plane curve Γ ⊂ ℝ2 at the point x∈Γ, is proposed. We derive a governing system of partial differential equations for the curvature, tangential angle, local length and position vector of an evolving family of plane curves and prove local in time existence of a classical solution. These equations include a non‐trivial tangential velocity functional governing a uniform redistribution of grid points and thus preventing numerically computed solutions from forming various instabilities. We discretize the governing system of equations in order to find a numerical solution for 2D anisotropic interface motions and image segmentation problems. Copyright © 2004 John Wiley & Sons, Ltd.
A mathematical model for the study of gliding motion of bacteria on a layer of non‐Newtonian slime
Authors: Hayat T. , Wang Y. , Siddiqui A. M. , Asghar S. 
Published: May 2004

AbstractThis paper is concerned with a mathematical hydrodynamical model of motility involving an undulating cell surface. The cell surface transmits stresses through a layer of exuded slime to the substratum. The slime is considered as a Johnson–Segalman fluid. A perturbation approach is used to find the analytic solution. Analytical expressions for the stream function, velocity, pressure gradient and pressure rise over a wavelength as well as the corresponding computational results are presented. The propulsive and lift forces and the power required for gliding propulsion have also been determined. The presented mechanism is found to generate a force for the propulsion of glider at a realistic speed and requires an output of power that is much less than the organism's metabolic rate of energy production. It is observed that unlike the Newtonian case of slime, the lift force is generated due to the Weissenberg number for non‐Newtonian slime, represented by the model of Johnson–Segalman fluid. It is also found that power required for translation in Johnson–Segalman fluid is reduced. Copyright © 2004 John Wiley & Sons, Ltd.
Existence and uniqueness of solutions of elastic string with moving ends
Authors: Rincon M. A. , Liu I‐Shih 
Published: May 2004

AbstractA mathematical model for the small vibration of an elastic string is considered. The model takes into account the change of tension due to the movement of the end points of the string. Under the assumptions that the speed of the moving ends be less than the characteristic speed of the equation, the existence and the uniqueness of local weak solution and global strong solution are proved. Copyright © 2004 John Wiley & Sons, Ltd.
Sparse symmetric preconditioners for dense linear systems in electromagnetism
Authors: Carpentieri B. , Duff I. S. , Giraud L. , Magolu monga Made M. 
Published: May 2004

AbstractWe consider symmetric preconditioning strategies for the iterative solution of dense complex symmetric non‐Hermitian systems arising in computational electromagnetics. In particular, we report on the numerical behaviour of the classical incomplete Cholesky factorization as well as some of its recent variants and consider also well‐known factorized approximate inverses. We illustrate the difficulties that those techniques encounter on the linear systems under consideration and give some clues to explain their disappointing behaviour. We propose two symmetric preconditioners based on Frobenius‐norm minimization that use a prescribed sparsity pattern. The numerical and computational efficiency of the proposed preconditioners are illustrated on a set of model problems arising both from academic and from industrial applications. Copyright © 2004 John Wiley & Sons, Ltd.
Matrix‐free constructions of circulant and block circulant preconditioners
Authors: Yang Chao , Ng Esmond G. , Penczek Pawel A. 
Published: May 2004

AbstractA framework for constructing circulant and block circulant preconditioners (C) for a symmetric linear system Ax=b arising from signal and image processing applications is presented in this paper. The proposed scheme does not make explicit use of matrix elements of A. It is ideal for applications in which A only exists in the form of a matrix vector multiplication routine, and in which the process of extracting matrix elements of A is costly. The proposed algorithm takes advantage of the fact that for many linear systems arising from signal or image processing applications, eigenvectors of A can be well represented by a small number of Fourier modes. Therefore, the construction of C can be carried out in the frequency domain by carefully choosing the eigenvalues of C so that the condition number of CT AC can be reduced significantly. We illustrate how to construct the spectrum of C in a way that allows the smallest eigenvalues of CT AC to overlap with those of A extremely well while making the largest eigenvalues of CT AC several orders of magnitude smaller than those of A. Numerical examples are provided to demonstrate the effectiveness of the preconditioner on accelerating the solution of linear systems arising from image reconstruction applications. Copyright © 2004 John Wiley & Sons, Ltd.
Preconditioning a mixed discontinuous finite element method for radiation diffusion
Authors: Warsa James S. , Benzi Michele , Wareing Todd A. , Morel Jim E. 
Published: May 2004

AbstractWe propose a multilevel preconditioning strategy for the iterative solution of large sparse linear systems arising from a finite element discretization of the radiation diffusion equations. In particular, these equations are solved using a mixed finite element scheme in order to make the discretization discontinuous, which is imposed by the application in which the diffusion equation will be embedded. The essence of the preconditioner is to use a continuous finite element discretization of the original, elliptic diffusion equation for preconditioning the discontinuous equations. We have found that this preconditioner is very effective and makes the iterative solution of the discontinuous diffusion equations practical for large problems. This approach should be applicable to discontinuous discretizations of other elliptic equations. We show how our preconditioner is developed and applied to radiation diffusion problems on unstructured, tetrahedral meshes and show numerical results that illustrate its effectiveness. Published in 2004 by John Wiley & Sons, Ltd.
Performance of parallel incomplete LDLt factorizations for solving acoustic wave propagation problems from industry
Authors: Made M. Magolu monga 
Published: May 2004

AbstractParallel incomplete LDLt (ParILDLt) factorizations are used to solve highly indefinite complex‐symmetric linear systems that arise from finite element discretization of acoustic wave propagation problems. The parallelization strategy is a generalized domain decomposition type approach in which adjacent subdomains have to exchange data during the construction of the incomplete factorization preconditioning matrix, as well as during each local forward and backward substitution. Comparison with the SYSNOISE (LMS International NV) direct solver, and the finite element tearing and interconnecting method for the Helmholtz equation (FETI‐H), is done in terms of execution time and memory usage. Challenging industrial problems are tested, showing that high performance is achieved with ParILDLt. Copyright © 2004 John Wiley & Sons, Ltd.
Parallel iterative solvers with selective blocking preconditioning for simulations of fault‐zone contact
Authors: Nakajima Kengo , Okuda Hiroshi 
Published: May 2004

AbstractIterative solvers with preconditioning are the most powerful choice for large‐scale scientific computation, especially for parallel computing. In non‐linear problems such as contact simulations for geophysics, the condition numbers of the coefficient matrices are usually large due to special constraint conditions. The result is slow convergence of the iterative solver. In this study, a new preconditioning method, called selective blocking is developed along with a special partitioning method for parallel finite‐element simulations on the GeoFEM platform. This newly developed method provides robust and smooth convergence and excellent parallel performance in 3D solid mechanics simulations for geophysics with contact conditions performed on a Hitachi SR2201 parallel computer with 128 processing elements. Copyright © 2004 John Wiley & Sons, Ltd.
A characteristic nonoverlapping domain decomposition method for multidimensional convection‐diffusion equations
Authors: Wang Hong , Liu Jiangguo , Espedal Magne S. , Ewing Richard E. 
Published: May 2004

AbstractWe develop a quasi‐two‐level, coarse‐mesh‐free characteristic nonoverlapping domain decomposition method for unsteady‐state convection‐diffusion partial differential equations in multidimensional spaces. The development of the domain decomposition method is carried out by utilizing an additive Schwarz domain decomposition preconditioner, by using an Eulerian‐Lagrangian method for convection‐diffusion equations and by delicately choosing appropriate interface conditions that fully respect and utilize the hyperbolic nature of the governing equations. Numerical experiments are presented to illustrate the method. © 2004 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq, 2005
Finite‐volume schemes for Friedrichs systems in multiple space dimensions: A priori and a posteriori error estimates
Authors: Jovanović Vladimir , Rohde Christian 
Published: May 2004

AbstractWe consider a class of finite‐volume schemes on unstructured meshes for symmetric hyperbolic linear systems of balance laws in two and three space dimensions. This class of schemes has been introduced and analyzed by Vila and Villedieu (1998). They have proven an a priori error estimate for approximations of smooth solutions. We extend the results to weak solutions. This is the base to derive an a posteriori error estimate for finite‐volume approximations of weak solutions. © 2004 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq, 2005
p53 protein expression does not correlate with EBV status in childhood B non‐hodgkin lymphomas
Authors: Klumb C.E. , Hassan R. , Zalcberg I.R. , Resende L.M.M. , Carriço M.K. , Maia R.C. 
Published: May 2004

AbstractBackgroundThe p53 tumor suppressor gene is affected in a wide range of human cancers, including hematological malignancies. This gene encodes a nuclear phosphoprotein p53, which plays a key role in cell cycle arrest, induction of apoptosis, and DNA repair. Mutations of the p53 gene often lead to the accumulation of the mutated protein in the nucleus of neoplastic cells. However, p53 protein expression is frequently detected in non‐Hodgkin lymphomas (NHL) without any correlation with p53 mutations. This discordance suggests the existence of other mechanisms to stabilize the p53 protein, including binding of p53 protein to viral proteins. p53 protein has been shown to bind to proteins encoded by the Epstein‐Barr virus (EBV).ProcedureThe aim of this study was to analyze p53 expression in childhood B‐NHL and correlate its expression in the absence of p53 mutations with EBV in order to investigate a possible involvement of EBV in p53 stabilization.Designs and MethodsTumor specimens from 35 children with B‐NHL were analyzed by immunohistochemistry (IHC) with the DO7 monoclonal antibody, which recognizes an epitope at N‐terminus of p53 protein and reacts with wild type and mutant proteins. To detect p53 mutations, PCR/SSCP and sequencing were performed. EBV status was determinated using a specific PCR technique.ResultsThe overall frequency of p53 immunostaining positivity was 45% (16 of 35). p53 mutations were detected in nine patients (25.6%). p53 immunoreactivity was observed in all cases with mutations. Additionally, we identified 7 p53 positive cases among 26 tumors without mutations. EBV DNA was detected in 24 of 35 cases. Four patients with p53 expression dissociated from mutation were EBV positive. No statistically significant association was found between p53 expression and EBV cases despite the exclusion of those patients in which p53 expression was related with p53 mutations (P = 0.28 and 0.54, respectively).ConclusionsOur results suggested that in childhood B‐NHL, the expression of p53 dissociated from mutations could not be related to EBV infection. Further studies with larger patient sets will be necessary to determinate if EBV‐encoded protein may play a role for nuclear accumulation of p53 protein. © 2004 Wiley‐Liss, Inc.