bluuebunny/crossref_metadata_2025_split huggingface dataset:
Velocity characteristics of steady flow through a straight generic inlet port
Authors: Chen A. , Lee K. C. , Yianneskis M. , Ganti G. 
Published: November 2005

AbstractThis paper presents a combined experimental and computational study of the steady flow through an internal combustion engine inlet port. The port was of generic design with a straight centreline. The three‐dimensional velocity and turbulence fields in the port and cylinder were simulated using a computational fluid dynamics programme. Laser sheet flow visualization and laser Doppler anemometry were also employed to investigate the flows and assess the predictions. The results show that a large‐scale flow structure is created in the cylinder by the inlet jet and its interaction with the valve and cylinder walls. Both predictions and measurements show that the flow is strongly dependent on the valve lift but is not affected by the flow rate. Comparisons of the numerical predictions with the experimental data indicated that the mean flow features are accurately predicted in many parts of the flow field; some discrepancies are evident and stem primarily from the failure of the simulation to predict a small recirculation region in the port which affects the trajectory of the annular jet entering the cylinder. Calculations were also made without modelling the port shape by using simplified inlet conditions upstream of the valve seat. It was found that this approximation can provide a reasonable, albeit less accurate, description of the flow, but modelling of the port shape is necessary for accurate flow predictions.
TLR3‐mediated signal induces proinflammatory cytokine and chemokine gene expression in astrocytes: Differential signaling mechanisms of TLR3‐induced IP‐10 and IL‐8 gene expression
Authors: Park Chanhee , Lee Soojin , Cho Ik‐Hyun , Lee Hyun Kyoung , Kim Donghoon , Choi Se‐Young , Oh Seog Bae , Park Kyungpyo , Kim Joong Soo , Lee Sung Joong 
Published: November 2005

AbstractViral infection is one of the leading causes of brain encephalitis and meningitis. Recently, it was reported that Toll‐like receptor‐3 (TLR3) induces a double‐stranded RNA (dsRNA)‐mediated inflammatory signal in the cells of the innate immune system, and studies suggested that dsRNA may induce inflammation in the central nervous system (CNS) by activating the CNS‐resident glial cells. To explore further the connection between dsRNA and inflammation in the CNS, we have studied the effects of dsRNA stimulation in astrocytes. Our results show that the injection of polyinosinic‐polycytidylic acid (poly(I:C)), a synthetic dsRNA, into the striatum of the mouse brain induces the activation of astrocytes and the expression of TNF‐α, IFN‐β, and IP‐10. Stimulation with poly(I:C) also induces the expression of these proinflammatory genes in primary astrocytes and in CRT‐MG, a human astrocyte cell line. Furthermore, our studies on the intracellular signaling pathways reveal that poly(I:C) stimulation activates IκB kinase (IKK), extracellular signal‐regulated kinase (ERK), and c‐Jun N‐terminal kinase (JNK) in CRT‐MG. Pharmacological inhibitors of nuclear factor‐κB (NF‐κB), JNK, ERK, glycogen synthase kinase‐3β (GSK‐3β), and dsRNA‐activated protein kinase (PKR) inhibit the expression of IL‐8 and IP‐10 in astrocytes, indicating that the activation of these signaling molecules is required for the TLR3‐mediated chemokine gene induction. Interestingly, the inhibition of PI3 kinase suppressed the expression of IP‐10, but upregulated the expression of IL‐8, suggesting differential roles for PI3 kinase, depending on the target genes. These data suggest that the TLR3 expressed on astrocytes may initiate an inflammatory response upon viral infection in the CNS. © 2005 Wiley‐Liss, Inc.
Second primary malignancy of the aerodigestive tract in patients treated for cancer of the oral cavity and larynx
Authors: Lin Karen , Patel Snehal G. , Chu Pen Yuan , Matsuo Jeannette M. S. , Singh Bhuvanesh , Wong Richard J. , Kraus Dennis H. , Shaha Ashok R. , Shah Jatin P. , Boyle Jay O. 
Published: November 2005

AbstractBackground.We aimed to identify patterns and predictors of second primary malignancy (SPM) of the aerodigestive tract (SPMADT) in patients with squamous cell carcinoma of the oral cavity (SCCOC) and larynx (SCCL).Methods.One thousand two hundred fifty‐seven patients from two existing databases were studied: 595 with SCCOC (1986–1995) and 662 with SCCL (1984–1998). The primary endpoint of interest was development of SPMADT, defined as a second primary neoplasm of the head and neck, esophagus, or lung.Results.The 5‐year SPMADT rate was 8% in the SCCL versus 10% in the SCCOC subgroup. Lung SPM was more common in the SCCL group; head and neck SPM was more common in the SCCOC group. Smokers had a fivefold increased risk, whereas alcohol use was associated with a twofold increased risk of SPMADT.Conclusions.The rates of SPMADT after treatment of SCCOC and SCCL are comparable, but the patterns are different. Smoking and alcohol use are independent predictors of SPMADT development. © 2005 Wiley Periodicals, Inc. Head Neck 27: XXX–XXX, 2005
Dexamethasone‐functionalized gels induce osteogenic differentiation of encapsulated hMSCs
Authors: Nuttelman Charles R. , Tripodi Margaret C. , Anseth Kristi S. 
Published: November 2005

AbstractSynthetic hydrogels represent highly controlled environments for three‐dimensional culture of human mesenchymal stem cells (hMSCs). Encapsulated hMSCs are presented with a “blank” environment, and this environment can be closely controlled in order to elicit an osteogenic response. In vitro, dexamethasone is an efficient and reliable factor that leads to the osteogenic differentiation of human mesenchymal stem cells (hMSCs). The aim of this work was to develop a dexamethasone‐releasing poly(ethylene glycol) (PEG)‐based hydrogel scaffold to deliver dexamethasone to encapsulated cells in a sustained manner. To accomplish this goal, dexamethasone was covalently linked to a photoreactive mono‐acrylated PEG molecule through a degradable lactide bond, and this molecule was covalently incorporated into the PEG hydrogel during photopolymerization. Over time, hydrolysis of the ester bonds resulted in dexamethasone release from the gel. The biological activity of the released dexamethasone was verified in monolayer cell culture and in three‐dimensional culture (i.e., in the gel) by the ability of hMSCs to express osteogenic genes, including alkaline phosphatase, osteopontin, and core binding factor alpha 1, as measured using real‐time reverse transcription polymerase chain reaction (RT‐PCR). These studies indicate that encapsulated hMSCs are capable of osteogenic differentiation in response to released dexamethasone. © 2005 Wiley Periodicals, Inc. J Biomed Mater Res, 2006
The transcriptional regulation role of BRD7 by binding to acetylated histone through bromodomain
Authors: Cong Peng , Jie Zhou , Ying Liu Hua , Ming Zhou , Li Wang Li , Hong Zhang Qiu , Xin Yang Yi , Wei Xiong , Rong Shen Shou , Ling Li Xiao , Yuan Li Gui 
Published: November 2005

AbstractStudies showed that the bromodomain binds to acetyl‐lysines on histone tails, which is involved in deciphering the histone codes. BRD7, a novel bromodomain gene, is the first described bromodomain gene involved in nasopharyngeal carcinoma (NPC). Previous studies showed that ectopic expression of BRD7 inhibited cell growth and cell cycle progression from G1 to S phase in HNE1 cells(a NPC cell line) by transcriptionally regulating some cell cycle related genes including E2F3 gene. In the present study, we revealed the co‐localization between acetylated H3 and BRD7 and found that the bromodomain of BRD7 is required for this co‐localization. More importantly, wild‐type BRD7 interacted with H3 peptide acetylated at Lys14, while the bromodomain deleted mutant lost this ability. We also found that the mutant BRD7 failed to regulate E2F3 promoter activity and inhibit cell cycle progression. These results indicated that the transcriptional regulation role of BRD7 was achieved by binding to acetylated histone H3 and that the bromodomain was essential for this role. In addition, no obvious changes were observed in the acetylated level of histone H3 after transfection with BRD7, indicating that chromatin remodeling, not chromatin modification, is the major mechanism of BRD7 mediated gene transcription. Taken together, the present work shed light on the fact that a novel bromodomain gene, BRD7, is of importance in transcriptional regulation and cellular events including cell cycle. J. Cell. Biochem. 97: 882–892, 2006. © 2005 Wiley‐Liss, Inc.
Aid heterogeneity: looking at aid effectiveness from a different angle
Authors: Mavrotas George 
Published: November 2005

AbstractThe paper uses an aid disaggregation approach to examine the impact of different aid modalities on the fiscal sector of the aid‐recipient country. It uses time‐series data on different types of development aid (project aid, programme aid, technical assistance and food aid) for Uganda, an important aid recipient in recent years, to estimate a model of fiscal response in the presence of aid which combines aid heterogeneity and endogenous aid. The empirical findings clearly suggest the importance of the above approach for delving deeper into aid effectiveness issues since different aid categories have different effects on key fiscal variables—an impact that could not be revealed if a single figure for aid were employed. Project and food aids appear to cause a reduction in public investment whereas programme aid and technical assistance are positively related to public investment. The same applies for government consumption. A negligible impact on government tax and non‐tax revenues, and a strong displacement of government borrowing are also found. Copyright © 2005 John Wiley & Sons, Ltd.
A boundary element Galerkin method for a hypersingular integral equation on open surfaces
Authors: Ervin V. J. , Stephan E. P. 
Published: November 2005

AbstractA hypersingular boundary integral equation of the first kind on an open surface piece Γ is solved approximately using the Galerkin method. As boundary elements on rectangles we use continuous, piecewise bilinear functions which vanish on the boundary of Γ. We show how to compensate for the effect of the edge and corner singularities of the true solution of the integral equation by using an appropriately graded mesh and obtain the same convergence rate as for the case of a smooth solution. We also derive asymptotic error estimates in lower‐order Sobolev norms via the Aubin–Nitsche trick. Numerical experiments for the Galerkin method with piecewise linear functions on triangles demonstrate the effect of graded meshes and show experimental rates of convergence which underline the theoretical results.
The initial boundary value problem for the Schröudinger equation
Authors: Abrahamsson Leif , Kreiss Heinz‐Otto 
Published: November 2005

AbstractWe study the stability properties of the one‐dimensional Schrödinger equation with boundary conditions that involve the derivative in the direction of propagation (or time). We show that this type of boundary condition might cause a strong growth of the amplitude of the solution. Such a model is not useful for numerical computations. One example is the parabolic wave equation in underwater acoustics for wave propagation in a downsloping duct with the normal derivative condition ∂u/∂n =0 at the bottom.
Regularity of solutions and approximate inertial manifolds for von Karman evolution equations
Authors: Chueshov I. D. 
Published: November 2005

AbstractThe necessary and sufficient conditions of regularity of solutions of von Karman evolution equations are derived. It is proved that a global attractor consists of smooth functions for these evolution equations. The results obtained are used to construct a family of approximate inertial manifolds. These finite dimensional manifolds approximate the global attractor and are determined by a simple iterative procedure. Their use makes it possible to suggest a new method of numerical investigation of long‐time behaviour and limit regimes of the equations in question. In particular, this method can be applied for studying a non‐linear flutter problem in real air space systems.
Quaternionic representation of the 3D elastic and thermoelastic boundary problems
Authors: Tsalik Alexander 
Published: November 2005

AbstractThis paper contains new representations of the 3D elasticity and thermoelasticity problems, expressed in terms of regular quaternion functions, which in 3D and 4D have properties analogous to those of complex analytical functions in 2D. The known and some new results, described in the paper, are used to formulate boundary 3D problems, related to the theory. The formulae obtained are very similar to those given by Muskhelishvili for 2D boundary problems. The obtained representations can be used for development of a 3D boundary element method in numerical analysis.
Dependence on diffusion time of apparent diffusion tensor of ex vivo calf tongue and heart
Authors: Kim Sungheon , Chi‐Fishman Gloria , Barnett Alan S. , Pierpaoli Carlo 
Published: November 2005

AbstractThe time dependence of the apparent diffusion tensor of ex vivo calf heart and tongue was measured for diffusion times (τd) between 32 and 810 ms. The results showed evidence of restricted diffusion in the muscle tissues of both organs. In regions where the myofibers are parallel, the largest eigenvalue (λ1) of the diffusion tensor remained the same for all diffusion times measured, while the other eigenvalues (λ2, λ3) decreased by 29–36% between τd = 32 ms and τd = 400 ms. In regions where the fibers cross, the λ1 also changed, decreasing by 17% between τd = 32 ms and τd = 400 ms. The restricting compartment size and volume fraction were effectively estimated by fitting the time courses of the eigenvalues to a model consisting of a nonrestricted compartment and a cylindrically restricted compartment. To our knowledge, this study is the first demonstrating diffusion time dependence of measured water diffusion tensor in muscular tissue. With improvement in scanning technology, future studies may permit noninvasive, in vivo detection of changes in muscle myoarchitecture due to disease, treatment, and exercise. Magn Reson Med, 2005. Published 2005 Wiley‐Liss, Inc.
Inference of multiple fiber orientations in high angular resolution diffusion imaging
Authors: Hosey Tim , Williams Guy , Ansorge Richard 
Published: November 2005

AbstractA method is presented that is capable of determining more than one fiber orientation within a single voxel in high angular resolution diffusion imaging (HARDI) data sets. This method is an extension of the Markov chain method recently introduced to diffusion tensor imaging (DTI) analysis, allowing the probability density function of up to 2 intra‐voxel fiber orientations to be inferred. The multiple fiber architecture within a voxel is then assessed by calculating the relative probabilities of a 1 and 2 fiber model. It is demonstrated that for realistic signal to noise ratios, it is possible to accurately characterize the directions of 2 intersecting fibers using a 2 fiber model. The shortcomings of under‐fitting a 2 fiber model, or over‐fitting a 1 fiber model, are explored. This new algorithm enhances the tools available for fiber tracking. Magn Reson Med, 2005. © 2005 Wiley‐Liss, Inc.
Displacement decomposition—incomplete factorization preconditioning techniques for linear elasticity problems
Authors: Blaheta Radim 
Published: November 2005

AbstractTwo preconditioning techniques for the numerical solution of linear elasticity problems are described and studied. Both techniques are based on spectral equivalence approach. The first technique consists in an incomplete factorization of the separate displacement component part of the stiffness matrix. The second technique uses an incomplete factorization of the isotropic approximation to the stiffness matrix. Results concerning existence, stability and efficiency of these preconditioning techniques are presented. The efficiency and robustness of the described techniques are illustrated by numerical experiments.
DRIC: A dynamic version of the RIC method
Authors: Notay Yvan 
Published: November 2005

AbstractA new incomplete factorization method is proposed, differing from previous ones by the way in which the diagonal entries of the triangular factors are defined. A comparison is given with the dynamic modified incomplete factorization methods of Axelsson–Barker and Beauwens, and with the relaxed incomplete Cholesky method of Axelsson and Lindskog. Theoretical arguments show that the new method is at least as robust as both previous ones, while numerical experiments made in the discrete PDE context show an effective improvement in many practical circumstances, particularly for anisotropic problems.
Orthogonal projection and total least squares
Authors: Fierro Ricardo D. , Bunch James R. 
Published: November 2005

AbstractOverdetermined linear systems often arise in applications such as signal processing and modern communication. When the overdetermined system of linear equations AX ≈︁ B has no solution, compatibility may be restored by an orthogonal projection method. The idea is to determine an orthogonal projection matrix P by some method M such that [Ã B̃] = P[A B], and ÃX = B̃ is compatible. Denote by XM the minimum norm solution to ÃX = B̃ using method M. In this paper conditions for compatibility of the lower rank approximation and subspace properties of Ã in relation to the nearest rank‐k matrix to A are discussed. We find upper and lower bounds for the difference between the solution XM and the SVD‐based total least squares (TLS) solution XSVD and also provide a perturbation result for the ordinary TLS method. These results suggest a new algorithm for computing a total least squares solution based on a rank revealing QR factorization and subspace refinement. Numerical simulations are included to illustrate the conclusions.
A modified direct preconditioner for indefinite symmetric Toeplitz systems
Authors: Concus Paul , Saylor Paul 
Published: November 2005

AbstractA modification is presented of the classical O(n2) algorithm of Trench for the direct solution of Toeplitz systems of equations. The Trench algorithm is stable for symmetric matrices that are positive definite, but can be unstable for the indefinite case (and for general matrices). Our modification permits extension of the algorithm to compute approximate inverses of indefinite symmetric Toeplitz matrices, for which the unmodified algorithm breaks down when principal submatrices are singular. As a preconditioner, the approximate inverse has an advantage that only matrix—vector multiplications are required for the solution of a linear system, without forward and backward solves. The approximate inverse so obtained can be sufficiently accurate, moreover, that, when it is used as a preconditioner for the applications investigated, subsequent iteration may not even be necessary. Numerical results are given for several test matrices. The perturbation to the original matrix that defines the modification is related to a perturbation in a quantity generated in the Trench algorithm; the associated stability of the Trench algorithm is discussed.
Modelling the pressure die casting process with the boundary element method: Steady state approximation
Authors: Davey K. , Hinduja S. 
Published: November 2005

AbstractThis paper describes a model which can predict the temperatures on the cavity surfaces of a die. The time varying boundary conditions are averaged so that the process can be modelled as a steady state problem. Since the model considers only thin components, it is reasonable to assume that the melt has totally solidified before ejection, and therefore the quantity of heat energy entering the die over the casting cycle can be estimated. This and other assumptions relating to the boundary conditions also enable the value of thermal resistance between the melt and the die to be estimated.Under certain conditions, subcooled nucleate boiling takes place in the cooling channels of the die. An iterative procedure is used to take account of this, which involves the repeated calculation of global heat transfer coefficients for the cooling channels, with the criteria that the total energy transferred through the channels is equal to that transferred due to boiling and convection.The boundary element method is used to predict the cavity temperatures. In die casting, only the temperatures on the cavity surfaces are of interest since the surface quality of a component is related significantly to the temperature distribution over the cavity. Since only thin components are considered herein, it is not necessary to model the solidifcation process and discretize the cast. These factors make the BEM ideally suited for the work described in this paper.To verify the model, the predicted temperatures for two components are compared with experimental values measured using thermocouples and a thermal imaging camera. It was found that there is fairly good agreement between the two sets of results.
Benchmark problems and testing of a finite element code for solidification in investment castings
Authors: Chandra U. 
Published: November 2005

AbstractOwing to an increased interest in numerical (finite element and finite difference) simulation of solidification in commercial investment castings, there is a need for proper evaluation of candidate codes. This paper presents a systematic selection of several benchmark problems designed to test modelling of latent heat release in pure metals and superalloys, thermal resistance at the metal/mould interface, temperature dependent material properties and far field radiation. For purpose of demonstration, these problems were analysed with a 2‐dimensional finite element code, TOPAZ, available in the public domain; one problem was analysed with its 3‐dimensional counterpart, TOPAZ3D, also. The numerical experimentation in the course of this study resulted in several findings of practical value, which are highlighted in the paper.
A refined global‐local finite element analysis method
Authors: Mao K. M. , Sun C. T. 
Published: November 2005

AbstractA refined global‐local method was proposed to improve the efficiency of finite element analysis. The proposed method was based on the regular finite element method in conjunction with three basic step, i.e. the global analysis, the local analysis and the refined global analysis. In the first two steps, a coarse finite element mesh was used to analyse the entire structure to obtain the nodal displacements which were subsequently used as displacement boundary conditions for local regions of interest. These local regions with the prescribed boundary conditions were then analysed with refined meshes to obtain more accurate stresses. In the third step, a new global displacement distribution based on the results of the previous two steps was assumed for the analysis, from which much improved solutions for both stresses and displacements were produced. Numerical examples showed that the proposed method yielded accurate solutions with significant savings in computing time compared with the regular finite element method. Further, this method is suitable for parallel computation.