bluuebunny/crossref_metadata_2025 huggingface dataset:
Adsorption separation of CH4/CO2 on mesocarbon microbeads: Experiment and modeling
Authors: Peng Xuan , Wang Wenchuan , Xue Ruisheng , Shen Zengmin
Published: November 2005

A novel meso‐porous material, the activated mesocarbon microbeads (a‐MCMBs) prepared by this group, is used for the separation of the CH4/CO2 mixture by experiment and modeling. First, the adsorption isotherm of nitrogen at 77K was measured to characterize the a‐MCMBs by the IGA‐003 gravimetric analyzer. Then, the adsorption experiments of pure CH4 and CO2 at ambient temperature of 298.15 K were carried out. A CH4/CO2 mixture is prepared at the mole ratio of 85:15, corresponding to the gas composition of the Ya‐13 gas field in the Qiongdongnan basin, China. Although only the total adsorption amount of the gas mixture on a‐MCMBs is available, the single adsorption amount for CH4 and CO2, also including the selectivity of CO2 over CH4, can be obtained by the Zhou, Gasem, and Robinson Equation of State (ZGR EOS). Finally, the adsorption behavior over a wide range of variables was predicted by the ZGR EOS method. The predicted greatest selectivity of CO2 over CH4 is 3.70 at 3.0 MPa, 258.15 K for the feed gas mole composition of CH4:CO2 = 40:60. Our results demonstrate that a‐MCMBs is not only suitable for CH4 storage, but also a promising adsorbent for separation of CH4/CO2. © 2005 American Institute of Chemical Engineers AIChE J, 2006
Synthesis, characterization and biological activity of diphenyltin(IV) complexes of N‐(3,5‐dibromosalicylidene)‐α‐amino acid and their diphenyltin dichloride adducts
Authors: Tian Laijin , Shang Zhicai , Zheng Xiaoliang , Sun Yuxi , Yu You , Qian Bochu , Liu Xueli
Published: November 2005

Diphenyltin(IV) complexes of N‐(3,5‐dibromosalicylidene)‐α‐amino acid, Ph2Sn[3,5‐Br2‐2‐OC6H2 CHNCH(R)COO] (where R = H, Me, i‐Pr, Bz), and their 1:1 adducts with diphenyltin dichloride, Ph2Sn[3,5‐Br2‐2‐OC6H2CHNCH(R)COO]·Ph2SnCl2, have been synthesized and characterized by elemental analysis, IR and NMR (1H, 13C and 119Sn) spectra. The crystal structure of Ph2Sn[3,5‐Br2‐2‐OC6H2CHNCH(i‐Pr)COO] shows a distorted trigonal bipyramidal geometry with the axial locations occupied by a carboxylate–oxygen and a phenolic–oxygen atom of the ligand, and that of Ph2Sn[3,5‐Br2‐2‐OC6H2CHNCH(i‐Pr)COO]·Ph2SnCl2 reveals that the two tin atoms are joined via the carbonyl atom of the ligand to form a mixed organotin binuclear complex. Bioassay indicates that the compounds possess better cytotoxic activity against three human tumor cell lines (HeLa, CoLo205 and MCF‐7) than cis‐platin and moderate antibacterial activity against two bacteria (E. coli and S. aureus). Copyright © 2005 John Wiley & Sons, Ltd.
Role of calcium‐dependent actin‐bundling proteins: Characterization of Dictyostelium mutants lacking fimbrin and the 34‐kilodalton protein
Authors: Pikzack Claudia , Prassler Josef , Furukawa Ruth , Fechheimer Marcus , Rivero Francisco
Published: November 2005

Actin‐bundling proteins organize actin filaments into densely packed bundles. In Dictyostelium discoideum two abundant proteins display calcium‐regulated bundling activity, fimbrin and the 34‐kDa protein (ABP34). Using a GFP fusion we observed transient localization of fimbrin at the phagocytic cup and macropinosomes. The distribution of truncated constructs encompassing the EF hands and the first actin‐binding domain (EA1) or both actin‐binding domains devoid of EF hands (A1A2) was indistinguishable from that of the full length protein. The role of fimbrin and a possible functional overlap with ABP34 was investigated in fim− and double 34−/fim− mutants. Except for a moderate cell size defect, fim− mutants did not show defects in growth, endocytosis, exocytosis, and chemotaxis. Double mutants were characterized by a small cell size and a defect in morphogenesis resulting in small fruiting bodies and a low spore yield. The cell size defect could not be overcome by expression of fimbrin fragments EA1 or A1A2, suggesting that both bundling activity and regulation by calcium are important. Induction of filopod formation in 34−/fim− cells was not impaired, indicating that both proteins are dispensable for this process. We searched in the Dictyostelium genome database for fimbrin‐like proteins that could compensate for the fimbrin defect and identified three unconventional fimbrins and two more proteins with actin‐binding domains of the type present in fimbrins. Cell Motil. Cytoskeleton 62:210–231, 2005. © 2005 Wiley‐Liss, Inc.
Cyclin D1 gene numerical aberration is a predictive marker for occult cervical lymph node metastasis in TNM Stage I and II squamous cell carcinoma of the oral cavity
Authors: Myo Kunihiro , Uzawa Narikazu , Miyamoto Ryozo , Sonoda Itaru , Yuki Yasuhiro , Amagasa Teruo
Published: November 2005

BACKGROUND

The management of occult cervical lymph node metastases originating from oral squamous cell carcinomas (OSCCs) remains controversial. The purpose of this study was to evaluate the value of cyclin D1 gene (CCND1) numerical aberrations in predicting the risk of late lymph node metastases.

METHODS

Fluorescence in situ hybridization (FISH), using a BAC clone specific for CCND1, was performed on OSCC specimens obtained by fine‐needle aspiration (FNA) biopsy from 45 patients with previously untreated TNM Stage I and II (T1‐2N0M0) disease who had not undergone elective cervical lymph node dissection.

RESULTS

CCND1 numerical aberrations were observed in 15 (33.3%) of the 45 patients and were significantly associated with the mode of invasion of the primary tumor (P = 0.01) and the presence of occult lymph node metastases (P < 0.001). Twelve of these 15 patients (80%) developed late cervical lymph node metastases within 2 years of surgery for primary OSCCs. All patients with cluster‐type amplification of CCND1 developed late lymph node metastases. Multivariate analysis showed that only CCND1 numerical aberrations (risk ratio, 8.685%, 95% confidence interval = 2.232–33.802, P = 0.002) independently predicted late cervical lymph node metastasis.

CONCLUSIONS

Aberrations in CCND1 numbers appear to be valuable in identifying patients at high risk of late lymph node metastasis in Stage I and II OSCCs. Analysis of CCND1 numerical aberrations using FISH on FNA biopsy specimens may be useful in selecting patients for elective cervical lymph node dissection. Cancer 2005. © 2005 American Cancer Society.
Finite element method for shallow water equation including open boundary condition
Authors: Kodama Toshio , Kawasaki Tomoyuki , Kawahara Mutsuto
Published: November 2005

A method to deal with an open boundary condition in the analysis of water surface waves, the tide, etc. by means of the finite element method is proposed in this paper. The present method has two important features relating to the treatment of the open boundary condition. The first feature is to consider the non‐reflective virtual boundary condition which has been developed in the numerical wave analysis method. The incident wave conditions without spurious reflected waves can be imposed at the open boundary. The second feature is to identify the amplitude of the components of incident waves in terms of observed water elevations in the field of standing waves. This can be done as a parameter identification based on an optimization problem by applying the conjugate gradient method. The applicability of this method to wave propagation problems is verified by several numerical computations.
Analysis of high‐speed continuous casting with inverse finite elements
Authors: Malamataris N. , Papanastasiou T. C.
Published: November 2005

A recently proposed inverse isotherm finite element method is further extended in order to account for processes with distorted isotherms. With this method a variety of problems can be solved which require the explicit calculation of characteristic material lines along with the common field of unknowns in transport phenomena. The method is applied to high‐speed metal casting, where the location and shape of the extensive solidification front is calculated simultaneously with the primary unknowns, the velocity and the pressure, whereas the temperature is fixed at the moving nodes of the finite element tessellation. This is achieved by solving the energy equation inversely along with the rest of the conservation equations, i.e. the temperature field is fixed and its location is calculated. Empirical correlations may be derived which give the shape of the solidification front as a function of the process parameters. This may be used to improve the control means of metal casting, which is currently based on one‐dimensional approximate analyses.
Flow of viscoelastic fluids through a porous channel—I
Authors: Ariel P. D.
Published: November 2005

The flow of viscoelastic fluids through a porous channel with one impermeable wall is computed. The flow is characterized by a boundary value problem in which the order of the differential equation exceeds the number of boundary conditions. Three solutions are developed: (i) an exact numerical solution, (ii) a perturbation solution for small R, the cross‐flow Reynold's number and (iii) an asymptotic solution for large R. The results from exact numerical integration reveal that the solutions for a non‐Newtonian fluid are possible only up to a critical value of the viscoelastic fluid parameter, which decreases with an increase in R. It is further demonstrated that the perturbation solution gives acceptable results only if the viscoelastic fluid parameter is also small.

Two more related problems are considered: fluid dynamics of a long porous slider, and injection of fluid through one side of a long vertical porous channel. For both the problems, exact numerical and other solutions are derived and appropriate conclusions drawn.
Finite element analysis of the axially symmetric motion of an incompressible viscous fluid in a spherical annulus
Authors: Ni W. , Nigro N. J.
Published: November 2005

This paper presents results obtained by employing a modified Galerkin finite element method to analyse the steady state flow of a fluid contained between two concentric, rotating spheres. The spheres are assumed to be rigid and the cavity region between the spheres is filled with an incompressible, viscous, Newtonian fluid. The inner sphere is constrained to rotate about a vertical axis with a prescribed angular velocity, while the outer sphere is fixed. Results for the circumferential function Ω, streamfunction ψ, vorticity function ζ and inner boundary torque T1 are presented for Reynolds numbers Re ⩽ 2000 and radius ratios 0.1 ⩽ α ⩽ 0.9. The method proved effective for obtaining results for a wide range of radius ratios (0.1 ⩽ α ⩽ 0.9) and Reynolds numbers (0 ⩽ Re ⩽ 2000). Previous investigators who employed the finite difference method experienced difficulties in obtaining results for cases with radius ratios α ⩽ 0.2, except for small Reynolds numbers (Re ⩽ 100). Results for Ω, Ψ, ζ and T1 obtained in this study for radius ratios 0.8 ≤ α ≤ 0.9 verified the development of Taylor vortices reported by other investigators. The research indicates that the method may be useful for analysing other non‐linear fluid flow problems.
Disperion under neutral atmospheric conditions
Authors: Glekas J. P. , Bergeles G. C.
Published: November 2005

A recently developed mesoscale numerical model has been applied to the Athens Basin in order to provide a detailed description of the mean flow and pollution levels under neutral atmospheric conditions. The model is based on the numerical solution of the time‐averaged Navier‐Stokes equations written in their contravariant strong conservation form in a generalized non‐orthogonal co‐ordinate system. Before its application to the Athens Basin case, the reliability of the model was tested by predicting the flow and concentration fields over a three‐dimensional hill. The predicted results agree favourably with available experimental data, demonstrating the validity, flexibility and economy of the model for flows in three‐dimensional complex terrain.
Development of the direct stress solution technique for three‐dimensional hydrodynamic models using finite elements
Authors: Luettich Richard A. , Hu Shending , Westerink Joannes J.
Published: November 2005

Velocity varies rapidly near sheared boundaries. Therefore in many practical fluid problems it can be inefficient to solve discrete equations with velocity as the dependent variable. Conversely, shear stress varies slowly near sheared boundaries, suggesting that it may be well suited for use as the dependent variable in discrete equations.

This paper describes a formulation of the internal mode equations for a three‐dimensional hydrodynamic model using shear stress as the dependent variable. The resulting direct stress solution (DSS), coupled with a spatial discretization using linear finite elements, yields a system matrix that can be set up and solved with the efficiency of a banded matrix with bandwidth 8. If the eddy viscosity distribution is assumed to be piecewise linear over the depth (with an arbitrary number of time‐varying segments), the recovery of velocity from stress can be easily accomplished in closed form, thereby avoiding any difficulty resulting from the logarithmic singularity in the velocity profile that occurs at a boundary.

Results from tidal and wind‐driven test cases with realistic boundary layers are used to demonstrate the accuracy and computational advantages of a DSS formulation versus a standard velocity‐based formulation.
Computation of confined coflow jets with three turbulence models
Authors: Zhu J. , Shih T.‐H.
Published: November 2005

A numerical study of confined jets in a cylindrical duct is carried out to examine the performance of two recently proposed turbulence models: an RNG‐based K‐ϵ model and a realizable Reynolds stress algebraic equation model. The former is of the same form as the standard K‐ϵ model but has different model coefficients. The latter uses an explicit quadratic stress‐strain relationship to model the turbulent stresses and is capable of ensuring the positivity of each turbulent normal stress. The flow considered involves recirculation with unfixed separation and reatachment points and severe adverse pressure gradients, thereby providing a valuable test of the predictive capability of the models for complex flows. Calculations are performed with a finite volume procedure. Numerical credibility of the solutions is ensured by using second‐order‐accurate differencing schemes and sufficiently fine grids. Calculations with the standard K‐ϵ model are also made for comparison. Detailed comparisons with experiments show that the realizable Reynolds stress algebraic equation model consistently works better than does the standard K‐ϵ model in capturing the essential flow features, while the RNG‐based K‐ϵ model does not seem to give improvements over the standard K‐ϵ model under the flow conditions considered.
Numerical predictions of the bifurcation of confined swirling flows
Authors: Jiang Tsung Leo , Shen Chih‐Hung
Published: November 2005

The bifurcation of confined swirling flows was numerically investigated by employing both the k‐ϵ and algebraic stress turbulence models. Depending upon the branch solution examined, dual flow patterns were predicted at certain swirl levels. In the lower‐branch solution which is obtained by gradually increasing the swirl level from a low‐swirl flow, the flow changes with increasing swirl number from the low‐swirl flow pattern to a high‐swirl flow pattern. In the upper‐branch solution which is acquired by gradually decreasing the swirl level from a high‐swirl flow, on the other hand, the flow can maintain itself in the high‐swirl flow pattern at the swirl levels where it exhibits the low‐swirl flow pattern in the lower branch. The bifurcation of confined swirling flows was predicted with either the k‐ϵ model or the algebraic stress model being employed. Both the k‐ϵ and algebraic stress models result in comparable and sufficiently good predictions for confined swirling flows if high‐order numerical schemes are used. The reported poor performance of the k‐ϵ model was clarified to be mainly attributable to the occurrence of the bifurcation and the use of low‐order numerical schemes.
Three‐dimensional modelling of steam flush for DNAPL site remediation
Authors: Forsyth P. A.
Published: November 2005

Numerical simulation of steam flush for clean‐up of non‐aqueous phase liquid (NAPL) contaminated groundwater sites involves solution of the multiphase, multicomponent subsurface flow equations. This paper describes techniques for discretizing problems with horizontal wells in a three‐dimensiontetrahedral mesh. The effectiveness of non‐linear flux limiters for reducing numerical dispersion is discussed. Primary variable selection and thermodynamic state transition rules will also be compared. Some example results for several steam flush scenarios will be presented.
Calculation of complex near‐wall turbulent flows with a low‐Reynolds‐number k‐ϵ model
Authors: Koutmos P. , Kostouros N. C.
Published: November 2005

An improved low‐Reynolds‐number k‐ϵ model has been formulated and tested against a range of DNS (direct numerical simulation) and experimental data for channel and complex shear layer flows. The model utilizes a new form of damping function adopted to account for both wall proximity effects and viscosity influences and a more flexible damping argument based on the gradient of the turbulent kinetic energy on the wall. Additionally, the extra production of the inhomogeneous part of the viscous dissipation near a wall has been added to the dissipation equation with significantly improved results. The proposed model was successfully applied to the calculation of a range of wall shear layers in zero, adverse and favourable pressure gradients as well as backward‐facing‐step separated flows.
On identification of flow separation and vortices in internal periodic flows
Authors: Rosenfeld Moshe
Published: November 2005

To permit simplified analysis of complex time‐dependent flows, possible relationship between the near‐wall flow, flow separation and vortices are studied numerically for a flow in a constricted two‐dimensional channel. The pulsating incoming wave‐form consists of a steady flow, followed by a half‐sinus flow superimposed on the steady component. One pair of vortices is created in each cycle, one vortex near each wall. The vortices propagate downstream in the next cycles, promoting flow separation as they move. Existing flow separation criteria were not found to be uniformly valid. A relation between the near‐wall flow and the vortical system exists only during the steady incoming flow phase of the cycle. It seems that local criteria of flow separation cannot be found for complex internal pulsating flow fields. However, the vorticity field can be utilized, even in complex time‐periodic flows, for identifying vortices that have been formed by the roll‐up of shear layers.
Analysis of unsteady wave processes in a rotating channel
Authors: Larosiliere L. M. , Mawid M.
Published: November 2005

The impact of passage rotation on the gasdynamic wave processes is analyzed through a numerical simulation of ideal shock‐tube flow in a closed rotating‐channel containing a gas in an initial state of homentropic solid‐body rotation. Relevant parameters of the problem such as wheel Mach number, hub‐to‐tip radius ratio, length‐to‐tip radius ratio, diaphragm temperature ratio, and diaphragm pressure ratio are varied. It is shown that for a fixed geometry and initial conditions, the contact interface acquires a distorted three‐dimensional time‐dependent orientation at non‐zero wheel Mach numbers. At a fixed wheel Mach number, the level of distortion depends primarily on the density ratio across the interface and also the hub‐to‐tip radius ratio. The nature of the rarefaction and shock wave propagation is one‐dimensional, although the acoustic waves are diffracted due to the radially varying propagation speed. Under conditions of initially homentropic solid‐body rotation, a degree of similarity exists between rotating and stationary shock‐tube flows. This similarity is exploited to arrive at an approximate analytical solution to the Riemann problem in a rotating shock‐tube.
Velocity characteristics of steady flow through a straight generic inlet port
Authors: Chen A. , Lee K. C. , Yianneskis M. , Ganti G.
Published: November 2005

This 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

Viral 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

Background.

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

Synthetic 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

Studies 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

The 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

A 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

We 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

The 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

This 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

The 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

A 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

Two 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

A 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

Overdetermined 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

A 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

This 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

Owing 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

A 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.
Stochastic design sensitivity in structural dynamics
Authors: Hien T. D. , Kleiber M.
Published: November 2005

A method to analyse stochastic design sensitivity for problems of structural dynamics is presented. A combination of the adjoint variable approach and the second order perturbation method is used in the finite element context. An alternative form of the constraint functional that holds for all times is introduced to consider the time response of dynamic sensitivity. The terminal problem of the adjoint system is solved using equivalent homogeneous equations exicited by initial velocities. The numerical procedures are shown to be much more efficient when based on the fold superposition technique: the generalized co‐ordinates are normalized and the correlated random variables are transformed to uncorrelated variables, whereas the secularities are eliminated by the fast Fourier transform of complex valued sequences. Numerical algorithms have been worked out and proved to be accurate and efficient; they can be readily adapted to fit into the existing finite element codes whose element derivative matrices can be explicitly generated. A number of numerical results for the deterministic and stochastic sensitivity analysis of beams and shells illustrates the paper.
Conservative versions of the locally exact consistent upwind scheme of second order (Lecusso‐scheme)
Authors: Günther Cl.
Published: November 2005

Two conservative versions of the recently introduced locally exact consistent upwind scheme of second order (LECUSSO‐scheme) are presented which both use four points (two upstream, one downstream) and do not suffer from wiggles. Test calculations using a flow problem with an exact analytical solution show that the two schemes, called LECUSSO‐C and QUICK‐PLUS, are superior to the original LECUSSO‐scheme and to several other standard difference schemes.
Optimal structural design with damping constraint limitations
Authors: Suweca W. , Jezequel L.
Published: November 2005

The algorithm optimization presented uses the optimality criteria method so as to minimize the total weight of the structure in the presence of a constraint of the damping type. The goal of this study is to increase the structural damping by optimizing the viscoelastic and elastic material distribution over the structure. The types of damping considered are hysteristic. The gradient of the constraint function in relation to the design variables is calculated with the aid of a complex variable sensitivity method. Several numerical results are presented to validate the algorithm proposed.
A galerkin symmetric boundary‐element method in elasticity: Formulation and implementation
Authors: Sirtori S. , Maier G. , Novati G. , Miccoli S.
Published: November 2005

Static discontinuities (i.e. distributions of forces along a line or a surface, implying a jump of tractions across it) and kinematic (displacement) discontinuities are considered simultaneously as sources acting on the unbounded elastic space Ω∞ along the boundary Γ of a homogeneous elastic body Ω embedded in Ω∞. The auxiliary elastic state thus generated in the body is associated with the actual elastic state by a Betti reciprocity equation. Using suitable discretizations of actual and fictitious boundary variables, a symmetric Galerkin formulation of the direct boundary element method is generated.

The following topics are addressed: reciprocity relations among kernels with particular attention to the role of singularities; conditions to be satisfied by the boundary field modelling in order to achieve the symmetry of the coefficient matrix; variational properties of the solution.

With reference to two‐dimensional problems, a technique based on a complex‐variable formalism is proposed to perform the double integrations involved in this approach. An implementation of this technique for elastic analysis is described assuming straight elements, with continuous linear displacements and piecewise‐constant tractions; all the double integrations are carried out analytically.

Comparisons, from the computational standpoint, with the traditional non‐symmetric method based on collocation and single integration, demonstrate the effectiveness of the present approach.