bluuebunny/crossref_metadata_2025_split huggingface dataset:
Coupled heat, water and gas flow in deformable porous media
Authors: Gawin Dariusz , Baggio Paolo , Schrefler Bernhard A. 
Published: August 2005

AbstractA fully coupled numerical model to simulate the slow transient phenomena involving heat and mass transfer in deforming porous media is developed. It makes use of the modified effective stress concept together with the capillary pressure relationship. The heat transfer through conduction and convection as well as the latent heat transfer (evaporation and/or condensation) is taken into account.The governing equations in terms of displacements, temperature, capillary pressure and gas pressure are coupled non‐linear differential equatiosn and are solved by the finite element method.The model is validated with respect to a documented experiment on semisaturated soil behaviour. Two other examples involving subsidence due to pumping from a phreatic aquifer and thermoelastic consolidation of saturated and semisaturated media are also presented.
Stability analysis of mixed finite element formulations with special mention of equal‐order interpolations
Authors: Idelsohn S. , Storti M. , Nigro N. 
Published: August 2005

AbstractWe present a method to assess the stability of pairs of interpolation spaces for mixed formulations. The method is based on a straightforward calculation of the eigenvalues of the discrete matrices through Fourier decomposition in plane waves and is intended to give, via straightforward numerical computations, a sharper determination of stability than the well‐known ‘patch test’ of Zienkiewicz et al. Special attention is devoted to the study of stability and accuracy of equal‐order interpolations.
Adaptive hybrid prismatic/tetrahedral grids
Authors: Kallinderis Y. 
Published: August 2005

AbstractEmployment of hybrid prismatic/tetrahedral grids is a relatively new approach for viscous flow computations with 3D complex geometries. The body surface is covered with triangles, which provides geometric flexibility, while the structure of the mesh in the direction normal to the surface provides thin prismatic elements suitable for the viscous region. The outermost layer of the prismatic grid is then used as the inner boundary surface for a tetrahedral grid which covers the rest of the computational domain. The hybrid grid is employed for performing Navier‐Stokes calculations in the prismatic region near the body and Euler calculations in the tetrahedral regions away from the body.The generation method of hybrid prismatic/tetrahedral grids marches a triangulated surface mesh away from the body to form a semi‐unstructured prismatic grid. Tetrahedra are then constructed which are linked directly to the nodes of the outermost prismatic layer. The hybrid grid is locally refined over both the prismatic and tetrahedral regions. Directional embedding of the prisms preserves the structure of the mesh in the normal‐to‐surface direction.
Investigation of generalized flux vector splitting for compressible flows on triangular meshes
Authors: Stoufflet Bruno 
Published: August 2005

AbstractThe paper presents some investigations in developing schemes based on a splitting of the Euler equations into a pure convective part and an acoustic part (pressure term) combined with a multidimensional treatment on unstructured triangular meshes. Two decompositions are considered and are compared with classical approaches on two‐dimensional inviscid flow simulations.
Integral transform solution of developing laminar duct flow in Navier‐Stokes formulation
Authors: Guerrero J. S. Perez , Cotta R. M. 
Published: August 2005

AbstractThe generalized integral transform technique is employed in the hybrid numerical‐analytical solution of the Navier‐Stokes equations in streamfunction‐only formulation, which govern the incompressible laminar flow of a Newtonian fluid within a parallel plate channel. Owing to the analytic nature of this approach, the outflow boundary condition for an infinite duct is handled exactly, and the error involved in considering finite duct lengths is investigated. The present error‐controlled solutions are used to inspect the relative accuracy of previously reported purely numerical schemes and to compare Navier‐Stokes and boundary layer formulations for various combinations of inlet conditions and Reynolds number.
Translation of a sphere in a rotating viscous fluid: A numerical study
Authors: Rao C. V. Raghava , Sekhar T. V. S. 
Published: August 2005

AbstractThe translation of a sphere moving along the axis of a rotating viscous fluid is studied by the finite difference method at moderate Reynolds (up to R = 500) and Taylor (up to T = 100) numbers. Suppression of the separation is observed with increasing rotation parameter T. The drag coefficient is also presented. It is observed that the drag coefficient is less than that with no rotation in the range 0<N<0·7, where N = 2T/R is the inverse Rossby number. The same phenomenon was observed experimentally by Maxworthy in the range 0<N<0·75±0·03.
Introduction of turbulent model in a mixed finite volume/finite element method
Authors: Le Ribault C. , Buffat M. , Jeandel D. 
Published: August 2005

AbstractThe aim of this work is to present a new numerical method to compute turbulent flows in complex configurations. With this in view, a k‐ϵ model with wall functions has been introduced in a mixed finite volume/finite element method. The numerical method has been developed to deal with compressible flows but is also able to compute nearly incompressible flows. The physical model and the numerical method are first described, then validation results for an incompressible flow over a backward‐facing step and for a supersonic flow over a compression ramp are presented. Comparisons are performed with experimental data and with other numerical results. These simulations show the ability of the present method to predict turbulent flows, and this method will be applied to simulate complex industrial flows (flow inside the combustion chamber of gas turbine engines). The main goal of this paper is not to test turbulence models, but to show that this numerical method is a solid base to introduce more sophisticated turbulence model.
Fluid dynamics of slender, thin, annular liquid jets
Authors: Ramos J. I. 
Published: August 2005

AbstractPerturbation methods are used to obtain the one‐dimensional, asymptotic equations that govern the fluid dynamics of slender, thin, inviscid, incompressible, axisymmetric, irrotational, annular liquid jets from the Euler equations. It is shown that, depending on the magnitude of the Weber number, two flow regimes are possible: an inertia‐dominated one corresponding to large Weber numbers, and a capillary regime for Weber numbers of the order of unity. The steady equations governing these two regimes have analytical solutions for the liquid's axial velocity component and require a numerical integration to determine the jet's mean radius for inertia‐dominated jets. The one‐dimensional equations derived in this paper are shown to be particular cases of a hydraulic model for annular liquid jets, and this model is used to determine the effects of gravity modulation on the unsteady fluid dynamics of annular liquid jets in the absence of mass injection into the volume enclosed by the jet and mass absorption. It is shown that both the convergence length and the pressure coefficient are periodic functions of time which have the same period as that of the gravity modulation, but undergo large variations as the amplitude, frequency and width of gravitational pulses is varied.
The instability of jets of arbitrary exit geometry
Authors: Baty Roy S. , Morris Philip J. 
Published: August 2005

AbstractThis paper describes a calculation technique to determine the linear instability characteristics of jets of arbitrary exit geometry. In particular, elliptic and rectangular jets are considered. The numerical procedure involves both a conformal transformation between the computational domain and the physical plane and a solution of the transformed stability equation in the computational domain. Modern, efficient, conformal mappings are used for both simply and doubly connected domains. The numerical solution is based on a hybrid finite difference/pseudospectral discretization of the stability equation. The technique is validated by comparison with previous stability calculations for circular and elliptic jets. Calculations are performed for the stability characteristics of elliptic and rectangular jets of aspect ratio 2:1. Growth rates, phase velocities, and pressure eigenfunctions are presented.
Ventral–striatal/nucleus–accumbens sensitivity to prediction errors during classification learning
Authors: Rodriguez P. F. , Aron A.R. , Poldrack R.A. 
Published: August 2005

AbstractA prominent theory in neuroscience suggests reward learning is driven by the discrepancy between a subject's expectation of an outcome and the actual outcome itself. Furthermore, it is postulated that midbrain dopamine neurons relay this mismatch to target regions including the ventral striatum. Using functional MRI (fMRI), we tested striatal responses to prediction errors for probabilistic classification learning with purely cognitive feedback. We used a version of the Rescorla‐Wagner model to generate prediction errors for each subject and then entered these in a parametric analysis of fMRI activity. Activation in ventral striatum/nucleus‐accumbens (Nacc) increased parametrically with prediction error for negative feedback. This result extends recent neuroimaging findings in reward learning by showing that learning with cognitive feedback also depends on the same circuitry and dopaminergic signaling mechanisms. Hum Brain Mapp, 2005. © 2005 Wiley‐Liss, Inc.
A preliminary in vitro and in vivo study of the effects of new anthraquinones on neutrophils and bone remodeling
Authors: Savarino L. , Benetti D. , Baldini N. , Tarabusi C. , Greco M. , Aloisi R. , Frascarelli S. , Fantozzi R. , Dianzani C. , Mian M. 
Published: August 2005

AbstractOsteolysis, that is, progressive periprosthetic bone loss, is responsible for approximately 70% of aseptic loosening and implant failure. Usually, it is due to a granulomatous reaction wear‐induced, leading to macrophage and osteoclast‐mediated bone resorption. At present, there is no established prophylaxis or treatment for this process. For this purpose, as a preliminary investigation, we aimed to study the effects in two directions, inhibition of proinflammatory signals, and bone remodeling activity, of two newly synthesized anthraquinone molecules [N,N′‐Diethylamino‐2,6‐anthraquinone‐disulfonamide (GR375) and N,N′‐(p‐ethoxyphenyl)‐2,6‐anthraquinone‐disulfon amide (GR377)]. Among the pro‐inflammatory signals, the ability of the two anthraquinones to interfere with the production of superoxide anion (O2−), which was assumed as a marker of reactive oxygen species (ROS), was evaluated in an in vitro cell model by testing phagocytes, such as human neutrophils, challenged by the chemotactic agent N‐formylmethionyl‐leucyl‐phenylalanine (FMLP). Both compounds inhibited O2− production, in a dose‐dependent way, without exerting scavenger effects. An in vivo model was applied to investigate their effect on bone remodeling. Fifty‐four female Wistar rats were divided into eight groups of six animals each, and a 4‐week treatment was applied in two phases. A 25 mg/kg/os dose in the first phase and 12.5–6.25mg/kg/os doses in the second one were employed. The tibia trabecular bone at the secondary spongiosa level was analyzed, and trabecular bone volume (%TBV), trabecular thickness (TbTh), and apatite lattice parameters were measured. At the highest doses of GR375 and GR377 the %TBV and the TbTh increased by 33.2, 34.6%, and 3.6 and 9.1%, respectively, whereas crystallographic parameters were not significantly different from the untreated group. Our results suggest a simultaneous antiinflammatory and antiosteoclastic activity of both drugs that encourages to perform further research. If it will be confirmed, they could be proposed in a variety of bone diseases, in particular, when acute inflammation is associated to osteolytic processes and, eventually, in the prevention and treatment of periprosthetic osteolysis. © 2005 Wiley Periodicals, Inc. J Biomed Mater Res, 2005
The effects of calcium phosphate deposition upon corrosion of CoCr alloys and the potential for implant failure
Authors: Lewis A. C. , Heard P. J. 
Published: August 2005

AbstractPhysical wear of orthopedic implants is inevitable. CoCr metal samples, typically used in joint reconstruction, corrode rapidly after removal of the protective oxide layer. The behavior of CoCr pellets immersed in human serum, fetal bovine serum (FBS), synovial fluid, and water were studied using time‐of‐flight secondary ion mass spectroscopy (ToF‐SIMS). The differences in the corrosive nature of human serum, FBS, synovial fluid, and water after 5 days immersion were highlighted by the oxide/hydroxide layer, which was, respectively, 25, 10, 1.5, and 3–3.5 nm thick. The thickness of calcium phosphate deposit from human serum, FBS, and synovial fluid was, respectively, 30, 20, and 2 nm. Co and Cr ions migrated from the bulk metal surface and were trapped in the serum deposits, where chromium existed as oxides, hydroxides, and phosphates, whereas the cobalt chemistry was dominated only by phosphates and hydroxides. This may account for the composition of wear debris from CoCr orthopedic implants, which are predominantly hydroxyphosphate compounds. From the literature, proteoglycans, pyrophosphates, phospholipids, lubricin, and superficial zone protein (SZP) have been identified as possible causes for the insignificant deposit of calcium phosphate from synovial fluid. Circulation of these compounds around the whole implant may inhibit calcium phosphate deposition and therefore contribute to osteolysis. © 2005 Wiley Periodicals, Inc. J Biomed Mater Res, 2005
PTEN enters the nucleus by diffusion
Authors: Liu Fenghua , Wagner Stefan , Campbell Robert B. , Nickerson Jeffrey A. , Schiffer Celia A. , Ross Alonzo H. 
Published: August 2005

AbstractDespite much evidence for phosphatidylinositol phosphate (PIP)‐triggered signaling pathways in the nucleus, there is little understanding of how the levels and activities of these proteins are regulated. As a first step to elucidating this problem, we determined whether phosphatase and tensin homolog deleted on chromosome 10 (PTEN) enters the nucleus by passive diffusion or active transport. We expressed various PTEN fusion proteins in tsBN2, HeLa, LNCaP, and U87MG cells and determined that the largest PTEN fusion proteins showed little or no nuclear localization. Because diffusion through nuclear pores is limited to proteins of 60,000 Da or less, this suggests that nuclear translocation of PTEN occurs via diffusion. We examined PTEN mutants, seeking to identify a nuclear localization signal (NLS) for PTEN. Mutation of K13 and R14 decreased nuclear localization, but these amino acids do not appear to be part of an NLS. We used fluorescence recovery after photobleaching (FRAP) to demonstrate that GFP‐PTEN can passively pass through nuclear pores. Diffusion in the cytoplasm is retarded for the PTEN mutants that show reduced nuclear localization. We conclude that PTEN enters the nucleus by diffusion. In addition, sequestration of PTEN in the cytoplasm likely limits PTEN nuclear translocation. © 2005 Wiley‐Liss, Inc.
Low pH and Helicobacter pylori increase nuclear factor kappa B binding in gastric epithelial cells: A common pathway for epithelial cell injury?
Authors: O'Toole Dermot , Abdel‐Latif Mohamed M.M. , Long Aideen , Windle Henry J. , Murphy Anne M. , Bowie Andrew , O'Neill Luke A.J. , Weir Donald G. , Kelleher Dermot 
Published: August 2005

AbstractHelicobacter pylori infection results in peptic ulceration and chronic gastritis through mechanisms which are not fully elucidated. Live H. pylori activate the pro‐inflammatory transcription factor NF‐κB in gastric epithelial cells. Patients may have peptic ulcer disease in the absence of H. pylori infection; therefore other factors contribute to the inflammatory process. Maximal acid output in patients with H. pylori infection and duodenal ulceration is significantly increased indicating a role for acid in the pathogenesis of mucosal ulceration. The effect of low pH on NF‐κB activation in gastric epithelial cells has not been studied. Human gastric epithelial cells (AGS) were exposed to a range of pH changes in the presence or absence of H. pylori. NF‐κB DNA‐binding and cytosolic IκB‐α were measured using electrophoretic mobility shift assay and Western blotting. NF‐κB DNA‐binding in gastric epithelial cells dramatically increased when the pH of the culture medium decreased. Increases in NF‐κB nuclear binding were paralleled by decreasing amounts of cytosolic IκB‐α. These findings were similar but less potent than those observed when cells were exposed to H. pylori. Low pH resulted in enhancement of H. pylori‐induced NF‐κB nuclear binding. DNA binding of NF‐κB activation secondary to low pH was attenuated by PD98059 but not by SB203580. Similar to H. pylori, low pH potently and independently augments NF‐κB nuclear binding in AGS cells and such activation appears to be mediated through MEK1‐dependant signaling pathways. © 2005 Wiley‐Liss, Inc.
Malaria‐suppressible expression of the anti‐apoptotic triple GTPase mGIMAP8
Authors: Krücken Jürgen , Epe Markus , Benten W. Peter M. , Falkenroth Nina , Wunderlich Frank 
Published: August 2005

AbstractThe IMAP/IAN family of AIG1‐like GTPases is conserved among vertebrates and angiosperm plants and has been postulated to regulate apoptosis, particularly in context with diseases such as cancer, diabetes, and infections. The human genes were recently renamed as gimap for GTPase of the immunity associated protein (GIMAP) family. Here we extend this new nomenclature to the murine gimap gene family. All gimap genes of the mouse are clustered on chromosome 6B with eight functional members and one pseudogene. The mGIMAP proteins contain one GTP‐binding site and display molecular masses between 33 and 38 kDa except for the very unusual 77 kDa mGIMAP8 protein, which is the first characterized protein containing three GTP‐binding domains. Northern blot analysis revealed expression of mgimap8 predominantly in the thymus. The low expression level observed in the spleen was further suppressed by Plasmodium chabaudi malaria. Confocal laser scanning microscopy demonstrated localization of mGIMAP8 at ER, Golgi, and mitochondria. Overexpression of mGIMAP8 could significantly impair anisomycin‐induced activation of caspase 3. Our data support the view that mGIMAP8 exerts an anti‐apoptotic effect in the immune system and is involved in responses to infections. © 2005 Wiley‐Liss, Inc.
Isolation and identification of 1α‐hydroxy‐3‐epi‐vitamin D3, a potent suppressor of parathyroid hormone secretion
Authors: Brown Alex J. , Ritter Cynthia S. , Weiskopf A.S. , Vouros P. , Sasso Gino J. , Uskokovic Milan R. , Wang Guochun , Reddy G. Satyanarayana 
Published: August 2005

AbstractSince our original demonstration of the metabolism of 1α,25(OH)2D3 into 1α,25(OH)2‐3‐epi‐D3 in human keratinocytes, there have been several reports indicating that epimerization of the 3 hydroxyl group of vitamin D compounds is a common metabolic process. Recent studies reported the metabolism of 25OHD3 and 24(R),25(OH)2D3 into their respective C‐3 epimers, indicating that the presence of 1α hydroxyl group is not necessary for the 3‐epimerization of vitamin D compounds. To determine whether the presence of a 25 hydroxyl group is required for 3‐epimerization of vitamin D compounds, we investigated the metabolism of 1αOHD3, a non‐25 hydroxylated vitamin D compound, in rat osteosarcoma cells (ROS 17/2.8). We noted metabolism of 1αOHD3 into a less polar metabolite which was unequivocally identified as 1αOH‐3‐epi‐D3 using the techniques of HPLC, GC/MS, and 1H‐NMR analysis. We also identified 1αOH‐3‐epi‐D3 as a circulating metabolite in rats treated with pharmacological concentrations of 1αOHD3. Thus, these results indicated that the presence of a 25 hydroxyl group is not required for 3‐epimerization of vitamin D compounds. Furthermore, the results from the same studies also provided evidence to indicate that 1αOH‐3‐epi‐D3, like 1αOHD3, is hydroxylated at C‐25. We then evaluated the biological activities of 1αOH‐3‐epi‐D3. Treatment of normal rats every other day for 7 days with 2.5 nmol/kg of 1αOH‐3‐epi‐D3 did not raise serum calcium, while the same dose of 1αOHD3 increased serum calcium by 3.39 ± 0.52 mg/dl. Interestingly, in the same rats which received 1αOH‐3‐epi‐D3 we also noted a reduction in circulating PTH levels by 65 ± 7%. This ability of 1αOH‐3‐epi‐D3 to suppress PTH levels in normal rats without altering serum calcium was further tested in rats with reduced renal function. The results indicated that the ED50 of 1αOH‐3‐epi‐D3 for suppression of PTH was only slightly higher than that of 1α,25(OH)2D3, but that the threshold dose of the development of hypercalcemia (total serum Ca > 10.5 mg/dl) was nearly 80 times higher. These findings indicate that 1αOH‐3‐epi‐D3 is a highly selective vitamin D analog with tremendous potential for treatment of secondary hyperparathyroidism in chronic renal failure patients. © 2005 Wiley‐Liss, Inc.
Interactions between the rabbit CSN1 gene and the nuclear matrix of stably transfected HC11 mammary epithelial cells vary with its level of expression
Authors: Poussin Karine , Hayes Hélène , Pauloin Alain , Chanat Eric , Fontaine Marie‐Louise , Aujean Etienne , Sun Jian‐Sheng , Debey Pascale , Devinoy Eve 
Published: August 2005

AbstractThe expression of casein genes is specific to the mammary gland and maximal during lactation. However, among the numerous mammary cell lines described so far, only a few express some casein genes. The regulatory regions of casein genes have been largely described but the mechanisms explaining the mammary specific expression of these genes, and their silencing in most mammary cell lines, have not yet been fully elucidated. To test the hypothesis that the nuclear location of the casein genes may affect their expression, we transfected HC11 mouse mammary cell line with a 100 kb DNA fragment surrounding the rabbit alpha S1 casein gene. We derived stable clones which express or not the transfected rabbit casein gene, in the same cellular context, independently of the number of transgene copies. Metaphase spreads were prepared from the different clones and the transfected genes were localized. Unexpectedly, we observed that in the original HC11 cell line the number of chromosomes per metaphase spread is close to 80, suggesting that HC11 cells have undergone a duplication event, since the mouse karyotype is 2n = 40. In alpha S1 casein expressing cells, the expression level does not clearly correlate with a localization of the transfected DNA proximal to the centromeres or the telomeres. Analysis of the localization of the transfected DNA in nuclear halos allows us to conclude that when expressed, transfected DNA is more closely linked to the nuclear matrix. The next step will be to study the attachment of the endogenous casein gene in mammary nuclei during lactation. © 2005 Wiley‐Liss, Inc.