bluuebunny/crossref_metadata_2025_split huggingface dataset:
Numerical computation of three‐dimensional incompressible Navier–Stokes equations in primitive variable form by DQ method
Authors: Shu C. , Wang L. , Chew Y. T. 
Published: September 2003

AbstractIn this paper, the global method of differential quadrature (DQ) is applied to solve three‐dimensional Navier–Stokes equations in primitive variable form on a non‐staggered grid. Two numerical approaches were proposed in this work, which are based on the pressure correction process with DQ discretization. The essence in these approaches is the requirement that the continuity equation must be satisfied on the boundary. Meanwhile, suitable boundary condition for pressure correction equation was recommended. Through a test problem of three‐dimensional driven cavity flow, the performance of two approaches was comparatively studied in terms of the accuracy. The numerical results were obtained for Reynolds numbers of 100, 200, 400 and 1000. The present results were compared well with available data in the literature. In this work, the grid‐dependence study was done, and the benchmark solutions for the velocity profiles along the vertical and horizontal centrelines were given. Copyright © 2003 John Wiley & Sons, Ltd.
Computation of turbulent free‐surface flows around modern ships
Authors: Li Tingqiu 
Published: September 2003

AbstractThis paper presents the calculated results for three classes of typical modern ships in modelling of ship‐generated waves. Simulations of turbulent free‐surface flows around ships are performed in a numerical water tank, based on the FINFLO‐RANS SHIP solver developed at Helsinki University of Technology. The Reynolds‐averaged Navier–Stokes (RANS) equations with the artificial compressibility and the non‐linear free‐surface boundary conditions are discretized by means of a cell‐centred finite‐volume scheme. The convergence performance is improved with the multigrid method. A free surface is tracked using a moving mesh technology, in which the non‐linear free‐surface boundary conditions are given on the actual location of the free surface. Test cases recommended are a container ship, a US Navy combatant and a tanker. The calculated results are compared with the experimental data available in the literature in terms of the wave profiles, wave pattern, and turbulent flow fields for two turbulence models, Chien's low Reynolds number k–εmodel and Baldwin–Lomax's model. Furthermore, the convergence performance, the grid refinement study and the effect of turbulence models on the waves have been investigated. Additionally, comparison of two types of the dynamic free‐surface boundary conditions is made. Copyright © 2003 John Wiley& Sons, Ltd.
Modelling solitons under the hydrostatic and Boussinesq approximations
Authors: Daily Chris , Imberger Jorg 
Published: September 2003

AbstractAn examination of solitary waves in 3D, time‐dependant hydrostatic and Boussinesq numerical models is presented. It is shown that waves in these models will deform and that only the acceleration term in the vertical momentum equation need be included to correct the wave propagation. Modelling of solitary waves propagating near the surface of a small to medium body of water, such as a lake, are used to illustrate the results. The results are also compared with experiments performed by other authors. Then as an improvement, an alternative numerical scheme is used which includes only the vertical acceleration term. Effects of horizontal and vertical diffusion on soliton wave structure is also discussed. Copyright © 2003 John Wiley & Sons, Ltd.
An implicit edge‐based ALE method for the incompressible Navier–Stokes equations
Authors: Smith Richard W. , Wright Jeffrey A. 
Published: September 2003

AbstractA new finite volume method for the incompressible Navier–Stokes equations, expressed in arbitrary Lagrangian–Eulerian (ALE) form, is presented. The method uses a staggered storage arrangement for the pressure and velocity variables and adopts an edge‐based data structure and assembly procedure which is valid for arbitrary n‐sided polygonal meshes. Edge formulas are presented for assembling the ALE form of the momentum and pressure equations. An implicit multi‐stage time integrator is constructed that is geometrically conservative to the precision of the arithmetic used in the computation. The method is shown to be second‐order‐accurate in time and space for general time‐dependent polygonal meshes. The method is first evaluated using several well‐known unsteady incompressible Navier–Stokes problems before being applied to a periodically forced aeroelastic problem and a transient free surface problem. Published in 2003 by John Wiley & Sons, Ltd.
A block‐implicit numerical procedure for simulation of buoyant swirling flows in a model furnace
Authors: de Lemos Marcelo J. S. 
Published: September 2003

AbstractThis work reports numerical results for the case of incompressible laminar heated flow with a swirl in a vertical cylindrical chamber. Computations are obtained with a point‐wise block‐implicit scheme. Flow governing equations are written in terms of the so‐called primitive variables and are recast into a general form. The discretized momentum equations are applied to each cell face and then, together with the mass‐continuity, tangential velocity and energy equations, are solved directly in each computational node. The effects of Rayleigh, Reynolds and Swirl numbers on the temperature field are discussed. Flow pattern and scalar residual history are reported. Further, it is expected that more advanced parallel computer architectures can benefit from the error smoothing operator here described. Copyright © 2003 John Wiley & Sons, Ltd.
3D free‐surface flow computation using a RANSE/Fourier–Kochin coupling
Authors: Guillerm Pierre‐Emmanuel , Alessandrini Bertrand 
Published: September 2003

AbstractA coupling method for numerical calculations of steady free‐surface flows around a body is presented. The fluid domain in the neighbourhood of the hull is divided into two overlapping zones. Viscous effects are taken in account near the hull using Reynolds‐averaged Navier–Stokes equations (RANSE), whereas potential flow provides the flow away from the hull. In the internal domain, RANSE are solved by a fully coupled velocity, pressure and free‐surface elevation method. In the external domain, potential‐flow theory with linearized free‐surface condition is used to provide boundary conditions to the RANSE solver. The Fourier–Kochin method based on the Fourier–Kochin formulation, which defines the velocity field in a potential‐flow region in terms of the velocity distribution at a boundary surface, is used for that purpose. Moreover, the free‐surface Green function satisfying this linearized free‐surface condition is used. Calculations have been successfully performed for steady ship‐waves past a serie 60 and then have demonstrated abilities of the present coupling algorithm. Copyright © 2003 John Wiley & Sons, Ltd.
A deconvolution‐based fourth‐order finite volume method for incompressible flows on non‐uniform grids
Authors: Iannelli P. , Denaro F. M. , Stefano G. De 
Published: September 2003

AbstractThis paper is concerned with the development of a new high‐order finite volume method for the numerical simulation of highly convective unsteady incompressible flows on non‐uniform grids. Specifically, both a high‐order fluxes integration and the implicit deconvolution of the volume‐averaged field are considered. This way, the numerical solution effectively stands for a fourth‐order approximation of the point‐wise one. Moreover, the procedure is developed in the framework of a projection method for the pressure–velocity decoupling, while originally deriving proper high‐order intermediate boundary conditions. The entire numerical procedure is discussed in detail, giving particular attention to the consistent discretization of the deconvolution operation. The present method is also cast in the framework of approximate deconvolution modelling for large‐eddy simulation. The overall high accuracy of the method, both in time and space, is demonstrated. Finally, as a model of real flow computation, a two‐dimensional time‐evolving mixing layer is simulated, with and without sub‐grid scales modelling. Copyright © 2003 John Wiley & Sons, Ltd.
Characteristic Euler shock‐fitting formulation for multi‐dimensional flows
Authors: Basesme Ertugrul A. , Akmandor I. Sinan , Ucer Ahmet S. 
Published: September 2003

AbstractA three‐dimensional explicit time marching algorithm has been developed for the numerical solution of inviscid internal flows. The formulation uses the natural streamline co‐ordinate system. The unsteady Euler equations in non‐conservative form are expressed in terms of the extended Riemann variables and the flow angles. Along the characteristic trajectories in the space–time domain, these equations reduce to a system of ordinary differential equations. Boundary conditions are also implemented in characteristic form. Shock waves are calculated after performing a one‐point shock correction that maintains conservation across the discontinuity. The algorithm has been applied to subsonic, transonic and supersonic test cases. Despite the wide range in the Mach number and the diversity of the tested flow geometries, close agreement have been obtained with available analytical and numerical results. Copyright © 2003 John Wiley & Sons, Ltd.
Somatosensory areas engaged during discrimination of steady pressure, spring strength, and kinesthesia
Authors: Bodegård Anna , Geyer Stefan , Herath Priyantha , Grefkes Christian , Zilles Karl , Roland Per E. 
Published: September 2003

AbstractThe aim of this study was to locate neuronal populations in the somatosensory areas engaged during discrimination of differences in: (1) static sustained pressure on the distal phalanx (PRESS); (2) spring strengths (SSTIFF) during active flexion of the right index finger; and (3) the change in position of a limb with contracting muscles, i.e., kinesthesia (KIN), during active flexion of the right index finger. The stimuli used were spring‐loaded cylinders. The regional cerebral blood flow (rCBF) was measured with positron emission tomography (PET). The active fields were related to cytoarchitectonic areas of the somatosensory cortex (areas 3a, 3b, 1, and 2) and the primary motor cortex (areas 4a and 4p). We hypothesized that SSTIFF and KIN would activate areas 3a and 2. All three conditions, when contrasted against a rest condition, activated cytoarchitectural areas 3b, 1, and 2, and presumptive somatosensory areas in the left parietal operculum and right supramarginal gyrus in accordance with these areas receiving information from cutaneous mechanoreceptive afferents. Area 3a was only activated in SSTIFF and KIN, consistent with observations in monkeys and cats, showing that afferents from muscle receptors project to area 3a, and indicating that a similar arrangement seems to be apparent in humans. SSTIFF and KIN activated the right anterior lobe of the cerebellum, the left area 4a and left area 2 more than did PRESS, likely due to a combination of active movements and muscle receptor feed‐back. Hum. Brain Mapp. 20:103–115, 2003. © 2003 Wiley‐Liss, Inc.
Modeling intra‐subject correlation among repeated scans in positron emission tomography (PET) neuroimaging data
Authors: Bowman F. DuBois , Kilts Clinton 
Published: September 2003

AbstractMany in vivo positron emission tomography (PET) neuroimaging studies record correlates of regional cerebral blood flow (rCBF) in a series of scans for each individual, usually under different experimental conditions. Typical methods for statistical analysis involve fitting voxel‐specific general linear models (GLM) that assume spherical normal errors, implying that all voxel‐specific rCBF measurements are independent and arise from identical normal probability distributions. While the spherical GLM provides a unified and computationally efficient approach to estimation, the likely correlations among an individual's repeated scans and heteroscedasticity between conditions prompt the use of extended statistical methodology. We outline a more general method to analyze PET data using random effects and correlated errors to model unequal variances across conditions as well as covariances (correlations) among the repeated scans for each individual. We introduce correlation maps to display intra‐subject correlations between an individual's rCBF measurements from different scans. We illustrate the application of our model using data from a study of social anxiety and highlight analytical advantages over the spherical GLM. Hum. Brain Mapping 20:59–70, 2003. © 2003 Wiley‐Liss, Inc.
Dopamine D2 receptors and transporters in type 1 and 2 alcoholics measured with human whole hemisphere autoradiography
Authors: Tupala Erkki , Hall Håkan , Bergström Kim , Mantere Tuija , Räsänen Pirkko , Särkioja Terttu , Tiihonen Jari 
Published: September 2003

AbstractIncreasing evidence implies the involvement of the dopamine (DA) system in the pathogenesis of alcoholism. We measured striatal DA D2 receptors in Cloninger type 1 and 2 alcoholics by using [125I]epidepride in human postmortem whole hemispheric autoradiography (WHA), which provides high‐resolution images corresponding to positron emission tomographic (PET) studies. We also evaluated the correlation between transporter and receptor DA binding site densities and putative correlation of [125I]epidepride binding between the dorsal striatum and nucleus accumbens. In the type 1 alcoholics, the DA D2 receptor density was 21.4–32.6% lower in all dorsal striatal structures (caudate, putamen, globus pallidus) when compared with the controls. Type 2 alcoholics had 19.6–21.4% lower binding in other dorsal striatal structures, except medial globus pallidus, where they were not significantly different from controls. The density of DA D2 receptors and DAT had a significant positive correlation only in the putamen of type 1 alcoholics. The binding of [125I]epidepride showed also consistent and statistically significant positive correlation between nucleus accumbens and all dorsal striatal areas in type 1 alcoholics but not in the controls. In the type 2 alcoholics, the correlation was weaker than that observed in the type 1 alcoholics, and no correlation was observed between nucleus accumbens and globus pallidus. Our results show that these two subgroups of alcoholics have stark differences in their DA D2 receptor binding characteristics. Type 2 alcoholics may have selective deficiency in the dorsal striatum, whereas in limbic structures they may not differ significantly from controls. Moreover, WHA provides a useful tool for detailed mapping of neuronal receptors in healthy as well as diseased brain, and can also be used in radioligand development for PET. Hum. Brain Mapp. 20:91–102, 2003. © 2003 Wiley‐Liss, Inc.
Asymmetry of subinsular anisotropy by in vivo diffusion tensor imaging
Authors: Cao Yue , Whalen Stephen , Huang Jie , Berger Kevin L. , DeLano Mark C. 
Published: September 2003

AbstractThe cortical regions specialized in speech–language exhibit a left–right asymmetry, e.g., a larger cortical size in the left auditory cortex and Wernicke's area. The possibility of developmental asymmetry in axonal fibers interconnecting speech–language cortical areas can be investigated by in vivo diffusion tensor imaging. Fifteen right‐handed native English speakers showed a markedly significant asymmetry (P < 0. 0005) in the relative anisotropy of water diffusion in the subinsular white matter, greater on the left. Additionally, the first principal diffusivity was greater and the second and third principal diffusivities were smaller on the left than right side. These results suggest the subinsular axonal structures developed differently between the left and right sides. A possible association between the hemispheric specialization in language and speech and the subinsular axonal fiber development is discussed. Hum. Brain Mapp. 20:82–90, 2003. © 2003 Wiley‐Liss, Inc.
Attenuation of brain BOLD response following lipid ingestion
Authors: Noseworthy Michael D. , Alfonsi Jeff , Bells Sonya 
Published: September 2003

AbstractA great deal of heterogeneity exists in fMRI data. Even within the same subject, results on successive days or scan sessions often differ in the number of significantly activated pixels and/or the intensity of activation. We sought to assess whether controllable physiologic modulators, such as dietary factors, could influence the outcome of fMRI data. A high fat diet, for example, prior to a fMRI scan could change microvascular blood rheologic factors and potentially alter brain blood oxygen‐level dependent (BOLD) signal patterns. In healthy adult volunteers, we measured brain BOLD signal during bilateral finger tapping (2 Hz) in the fasted state, and at 40 and 100 minutes post‐ingestion of a 235 mL can of Ensure Plus (Ross Labs), alone or supplemented with either 25cc or 50cc of canola oil. Both the 25cc and 50cc Canola oil treatments produced a significant bilateral decrease in BOLD signal 40 and 100 minutes postprandial. No significant effect was observed with Ensure in the absence of oil. Therefore, to decrease fMRI within and between subject heterogeneity, and thereby increase fMRI statistical power, it is suggested that scanning within 2 hours post high fat ingestion should be avoided. As a corollary, a thorough understanding of a subject's physiological state, prior to an fMRI exam, may reduce the impact of other confounding variables. Hum. Brain Mapp. 20:116–121, 2003. © 2003 Wiley‐Liss, Inc.
Tonotopic cortical representation of periodic complex sounds
Authors: Cansino Selene , Ducorps Antoine , Ragot Richard 
Published: September 2003

AbstractMost of the sounds that are biologically relevant are complex periodic sounds, i.e., they are made up of harmonics, whose frequencies are integer multiples of a fundamental frequency (Fo). The Fo of a complex sound can be varied by modifying its periodicity frequency; these variations are perceived as the pitch of the voice or as the note of a musical instrument. The center frequency (CF) of peaks occurring in the audio spectrum also carries information, which is essential, for instance, in vowel recognition. The aim of the present study was to establish whether the generators underlying the 100m are tonotopically organized based on the Fo or CF of complex sounds. Auditory evoked neuromagnetic fields were recorded with a whole‐head magnetoencephalography (MEG) system while 14 subjects listened to 9 different sounds (3 Fo × 3 CF) presented in random order. Equivalent current dipole (ECD) sources for the 100m component show an orderly progression along the y‐axis for both hemispheres, with higher CFs represented more medially. In the right hemisphere, sources for higher CFs were more posterior, while in the left hemisphere they were more inferior. ECD orientation also varied as a function of the sound CF. These results show that the spectral content CF of the complex sounds employed here predominates, at the latency of the 100m component, over a concurrent mapping of their periodic frequency Fo. The effect was observed both on dipole placement and dipole orientation. Hum. Brain Mapping 20:71–81, 2003. © 2003 Wiley‐Liss, Inc.
Progression through the G1‐phase of the on‐going cell cycle
Authors: Boonstra Johannes 
Published: September 2003

AbstractCell cycle progression is dependent upon the action of cyclins and their partners the cyclin dependent kinases (CDKs). Each cell cycle phase has its own characteristic cyclin‐CDK combination, cyclin D‐CDK4,6 and cyclin E‐CDK2 being responsible for progression through G1‐phase into S‐phase. Progression through G1‐phase is regulated by signal transduction cascades activated by polypeptide growth factors and by extracellular matrix (ECM) components. Studies aiming to unravel the molecular mechanism by which these extracellular components activate the cyclin‐CDK complexes in the G1‐phase, are usually performed using serum‐starved cells (G0 cells). These cells are activated by addition of growth factors, or the cells are detached from the substratum by trypsinization and subsequently allowed to re‐attach. An alternative approach, however, is to study the effects of growth factors and attachment in the ongoing cell cycle by synchronization of the cells by the mitotic shake‐off method. These cells are not serum starved and not actively detached from the substratum. In this contribution it is shown that both methods yield significant different results. These observations demonstrate that data obtained with model systems should be interpreted with care, especially if the findings are used to explain cell cycle progression in cells in an intact organism. J. Cell. Biochem. 90: 244–252, 2003. © 2003 Wiley‐Liss, Inc.
Catalase, but not MnSOD, inhibits glucose deprivation‐activated ASK1‐MEK‐MAPK signal transduction pathway and prevents relocalization of Daxx: Hydrogen peroxide as a major second messenger of metabolic oxidative stress
Authors: Song Jae J. , Lee Yong J. 
Published: September 2003

AbstractOverexpression of catalase, but not manganese superoxide dismutase (MnSOD), inhibited glucose deprivation‐induced cytotoxicity and c‐Jun N‐terminal kinase 1 (JNK1) activation in human prostate adenocarcinoma DU‐145 cells. Suppression of JNK1 activation by catalase overexpression resulted from inhibition of apoptosis signal‐regulating kinase 1 (ASK1) activation by preventing dissociation of thioredoxin (TRX) from ASK1. Overexpression of catalase also inhibited relocalization of Daxx from the nucleus to the cytoplasm as well as association of Daxx with ASK1 during glucose deprivation. Taken together, hydrogen peroxide (H2O2) rather than superoxide anion (O2•−) acts as a second messenger of metabolic oxidative stress to activate the ASK1‐MAPK/extracellular signal‐regulated kinase (ERK) kinase (MEK)‐mitogen‐activated protein kinase (MAPK) signal transduction pathway. J. Cell. Biochem. 90: 304–314, 2003. © 2003 Wiley‐Liss, Inc.