bluuebunny/crossref_metadata_2025 huggingface dataset:
Numerical simulation of complex flows of non‐Newtonian fluids using the stream tube method and memory integral constitutive equations
Authors: Bereaux Yves , Clermont Jean‐Robert
Published: October 2005

In this paper a memory integral viscoelastic equation is considered for simulating complex flows of non‐Newtonian fluids by stream tube analysis. A formalism is developed to take into account co‐deformational memory equations in a mapped computational domain where the transformed streamlines are parallel and straight. The particle‐tracking problem is avoided. Evolution in time and related kinematic quantities involved with a K‐BKZ integral constitutive model are easily taken into account in evaluating the stresses. Successive subdomains, the stream tubes, may be considered for computing the main flow in abrupt axisymmetric contractions from the wall to the central flow region. The ‘peripheral stream tube’ close to the duct wall is determined by developing a non‐conventional modified Hermite element. A mixed formulation is adopted and the relevant non‐linear equations are solved numerically by the Levenberg‐Marquardt algorithm. Although the singularity at the section of contraction is not involved explicitly, the results obtained for the peripheral stream tube clearly show the singularity effects and the extent of the recirculating zone near the salient corner. The algorithm is stable even at high flow rates and provides satisfactory solutions when compared with similar calculations in the literature.
Inhibitory effect of minocycline on amyloid β fibril formation and human microglial activation
Authors: Familian Atoosa , Boshuizen Ronald S. , Eikelenboom Piet , Veerhuis Robert
Published: October 2005

Minocycline, a derivative of the antibiotic tetracycline, displays neuroprotective properties in various models of neurodegenerative diseases and is now used in clinical trials, because of its relative safety and tolerability. Minocycline passes the blood‐brain barrier and is presumed to inhibit microglial activation. In Alzheimer's disease brain, a number of proteins, including serum amyloid P component (SAP) and complement factors such as C1q, accumulate in amyloid β (Aβ) plaques. In a previous study, SAP and C1q were found to be required for clustering of activated microglia in Aβ plaques. Furthermore, SAP and C1q enhanced Aβ fibril formation and Aβ mediated cytokine release by human microglia in vitro. In the present study, we report that tetracycline and minocycline dose‐dependently reduce TNF‐α and IL‐6 release by adult human microglia upon stimulation with a combination of Aβ, SAP, and C1q. In addition, minocycline and to a lesser extent tetracycline inhibit fibril formation of Aβ as determined in a thioflavin‐S‐based fluorescence test. This inhibitory effect was observed with Aβ alone as well as with Aβ in combination with SAP and C1q. Our data suggest that minocycline and tetracycline at tolerable doses can inhibit human microglial activation. This activity in part is exerted by inhibition of (SAP and C1q enhanced) Aβ fibril formation. © 2005 Wiley‐Liss, Inc.
A customized retroviral vector confers marker gene expression in osteoclast lineage cells
Authors: Selski Daniel J. , Clohisy Denis R.
Published: October 2005

Osteoclasts play a seminal role in many skeletal diseases and therefore are candidates for cell‐based gene delivery systems to treat disorders of bone. As an initial step toward developing osteoclast‐mediated gene delivery systems, we have made and analyzed a customized Molony–Murine leukemia virus (MMLV)‐based retroviral vector containing elements of the osteoclast‐specific tartrate‐resistant acid phosphatase (TRAP) gene. RAW 264.7 cells were transduced with the customized vector (E3) and differentiated along macrophage or osteoclast lineages. E3 contained a truncated form of the human nerve growth factor receptor (NGFR) as a reporter gene. NGFR expression increased with RANK‐ligand (RANK‐L) treatment but not with macrophage (γ‐IFN/LPS treatment) differentiation. Enhanced NGFR expression peaked 48 h after RANK‐L treatment. Electrophoretic mobility shift assays (EMSA) analysis of the TRAP gene regulatory elements in E3 identified a single 27 bp DNA probe, which specifically bound protein from RANK‐L‐treated cells. DNA sequence revealed AP‐1 binding sites, and analysis with mutant probes implied that the sites were functional. EMSA supershift analysis identified Fos protein interacting with the 27 bp probe. In summary, insertion of sequence −962 to −868 from the TRAP gene into the U3 region of the MMLV LTR confers RANK‐L induced retroviral gene expression via Fos family protein interaction at AP‐1 sites. J. Cell. Biochem. © 2005 Wiley‐Liss, Inc.
Tumor necrosis factor‐related apoptosis‐inducing ligand (TRAIL) regulates endothelial nitric oxide synthase (eNOS) activity and its localization within the human vein endothelial cells (HUVEC) in culture
Authors: Di Pietro Roberta , Mariggiò Maria A. , Guarnieri Simone , Sancilio Silvia , Giardinelli Annalisa , Di Silvestre Sara , Consoli Agostino , Zauli Giorgio , Pandolfi Assunta
Published: October 2005

We have recently demonstrated that tumor necrosis factor‐related apoptosis‐inducing ligand (TRAIL) increases endothelial nitric oxide synthase (eNOS) phosphorylation, NOS activity, and nitric oxide (NO) synthesis in cultured human umbilical vein endothelial cells (HUVEC), without inducing apoptotic cell death. Although an important factor that regulates eNOS activity is its localization within the cells, little is known about the role of TRAIL in the regulation of eNOS trafficking among cellular compartments and the cytoskeleton involvement in this machinery. Then, we did both quantitative and semi‐quantitative evaluations with biochemical assays and immune fluorescence microscopy in the presence of specific inhibitors of NOS activity as well as of cytoskeletal microtubule structures. In our cellular model, TRAIL treatment not only increased NO levels but also caused a time‐dependent NO migration of fluorescent spots from the plasma membrane to the inner part of the cells. In unstimulated cells, most of the eNOS was localized at the cell membranes. However, within 10 min following addition of TRAIL, nearly all the cells showed an increased cytoplasm localization of eNOS which appeared co‐localized with the Golgi apparatus at a higher extent than in unstimulated cells. These effects were associated to an increased formation of trans‐cytoplasm stress fibers with no significant changes of the microtubule network. Conversely, microtubule disruption and Golgi scattering induced with Nocodazole treatment inhibited TRAIL‐increased NOS activity, indicating that, on cultured HUVEC, TRAIL ability to affect NO production by regulating eNOS sub‐cellular distribution is mediated by cytoskeleton and Golgi complex modifications. J. Cell. Biochem. 97: 782–794, 2006. © 2005 Wiley‐Liss, Inc.
Modifications of orientational dependence of microscopic magnetic resonance imaging T2 anisotropy in compressed articular cartilage
Authors: Alhadlaq Hisham A. , Xia Yang
Published: October 2005

Purpose

To investigate the compression‐induced changes in the orientational characteristics in T2 anisotropy of articular cartilage using microscopic magnetic resonance imaging (μMRI).

Materials and Methods

Six beagle specimens were subjected to various levels of strain (0% to 27%) and were imaged at a minimum of two orientations (0° and 55°). Two specimens at 14% and 27% strain were imaged at every 5° increment over the first quadrant of the angular space. Quantitative two‐dimensional T2 images and three‐dimensional T2 anisotropy maps of cartilage were constructed at a 19.8‐μm in‐depth resolution.

Results

The load‐induced laminar appearance of cartilage at the magic angle became more distinct as the strain level increased. T2 anisotropy maps of cartilage at 14% and 27% strain exhibited load‐induced modifications in the collagen fibril ultrastructure, with a new peak toward the cartilage‐bone interface and alterations to orientational dependence of T2 anisotropy.

Conclusion

Distinct alternations in the orientational dependence of μMRI T2 anisotropy reflect the organizational modification of the collagen matrix due to external loading. This approach could become useful in detecting changes in cartilage's macromolecular structure due to injury or diseases. J. Magn. Reson. Imaging 2005. © 2005 Wiley‐Liss, Inc.
Nonacid cleavable detergents applied to MALDI mass spectrometry profiling of whole cells
Authors: Norris Jeremy L. , Hangauer Matthew J. , Porter Ned A. , Caprioli Richard M.
Published: October 2005

Although cleavable detergents were first synthesized a number of years ago, they have only recently been successfully applied to problems involving biological molecules. Recent reports have demonstrated that these compounds are useful for applications involving both 2D PAGE and mass spectrometry. However, most cleavable surfactants have utilized acid‐labile functional groups to affect cleavage. In applications where extreme pH is required, acid cleavable detergents have limited usefulness. We report the synthesis of fluoride cleavable silane compounds and photolabile cinnamate esters as cleavable detergents having alternative cleavage chemistries than previously reported cleavable detergents. These compounds were applied to whole cell analysis using MALDI mass spectrometry, and it was demonstrated that their use results in an increase in the number of proteins analyzed by increasing protein solubility. Copyright © 2005 John Wiley & Sons, Ltd.
Theoretical study of the gas‐phase structures of sodiated and cesiated leucine and isoleucine: zwitterionic structure disfavored in kinetic method experiments
Authors: Rožman Marko
Published: October 2005

The most stable charge‐solvated (CS) and zwitterionic (ZW) structures of sodiated and cesiated leucine and isoleucine were studied by density functional theory methods. According to the Boltzmann distribution in gas phase, both forms of LeuNa+ and IleNa+ exist, but in LeuCs+ and IleCs+, the ZW forms are dominant. Results for the sodiated compounds are consistent with the relationship found between decrease in relative stability of CS versus ZW form and aliphatic amino acid side chain length. The observed degeneracy in energy for IleNa+ conformers is at odds with kinetic method results. Additional calculations showed that kinetic method structural determinations for IleNa+ do not reflect relative order of populations in the lowest energy conformers. Since complexation of cationized amino acids into ion‐bound dimers disfavors ZW structure by ∼8 kJ mol−1, it is suggested that for energy close conformers of sodium‐cationized amino acids, the kinetic method may not be reliable for structural determinations. Copyright © 2005 John Wiley & Sons, Ltd.
Influence of initial charge state on fragmentation patterns for noncovalent drug/DNA duplex complexes
Authors: Keller Karin M. , Zhang Junmei , Oehlers Leon , Brodbelt Jennifer S.
Published: October 2005

The charge state–dependent dissociation of various DNA duplexes and drug/duplex complexes has been investigated using collisionally activated dissociation (CAD) in a quadrupole ion trap mass spectrometer (QIT‐MS). Several non‐self‐complementary 14‐residue oligonucleotides were employed, in addition to an array of known DNA‐interactive ligands, including the intercalators daunomycin and nogalamycin, as well as the minor groove binding agents distamycin, netropsin, 4′,6‐diamidino‐2‐phenylindole, and Hoechst 33342. In general, the dissociation pathways exhibited by both the duplexes and the drug/duplex complexes were found to be markedly sensitive to initial charge state. Time‐ and activation voltage–independent duplex strand separation predominated for higher charge states, which was interpreted to be a result of internal Coulombic repulsion or partial unzipping in the interface, while time‐ and activation voltage–dependent covalent cleavage predominated for lower charge states. The identity of the drug and the sequence of the duplex were both found to affect the competition between different dissociation processes. The dissociation pathways for the lower charge state complexes are probably more reflective of specific drug–DNA interactions because Coulombic and/or conformational effects are less marked for these precursors. Copyright © 2005 John Wiley & Sons, Ltd.
Differentiation of Boc‐ α,β‐ and β,α‐peptides and a pair of diastereomeric β,α‐dipeptides by positive and negative ion electrospray tandem mass spectrometry (ESI‐MS/MS)
Authors: Reddy P. Nagi , Srikanth R. , Swamy N. S. , Srinivas R. , Sharma G. V. M. , Nagendar Pendem , Krishna Palakodety Radha
Published: October 2005

Positive and negative ion electrospray ionization (ESI) tandem mass spectral study of a new series of hybrid peptides, viz, BocN‐α,β‐peptides and BocN‐β,α‐peptides, synthesized from C‐linked carbo‐β3‐amino acids [Caa (S)] and L‐Ala has been carried out. The α,β‐peptides have been differentiated from β,α‐peptides by the collision‐induced dissociation (CID) of [M + H]+ and [M − H]− ions in positive and negative ion ESI‐MS respectively. The fragment ion [M + H − C(CH3)3 + H]+ formed from [M + H]+ ions by the loss of 2‐methyl‐prop‐2‐ene in α,β‐peptides with L‐Ala at the N‐terminus is insignificant or totally absent for β,α‐peptides which have the Caa (S) at N‐terminus. The fragment ion [M − H‐C(CH3)3OH − HNCO]− formed from [M − H]− of β,α‐peptide acids is totally absent for α,β‐peptide acids. This has been attributed to the absence of the β‐methylene group in α,β‐peptides, and the participation of the β‐methylene group in the loss of HNCO in β,α‐peptide acids is confirmed by the deuteration experiments. The CID of [M + H‐Boc + H]+ ions of these peptides also produce characteristic fragmentation. In the CID spectra of α,β‐peptides, the bn+ ions and the resulting yn+ ions occur at a mass difference of 243 and 71 Da corresponding to the successive losses of Caa and L‐Ala, whereas a mass difference of 71 and 243 Da is observed for β,α‐peptides. In contrast to the CID of protonated peptides, the CID of [M − H]− ions of the α,β‐ and β,α‐peptide acids do not give bn− ions and show abundant zn− ions. Further, a pair of diastereomeric dipeptide esters and acids have been distinguished by the CID of [M + H]+ ions. The loss of 2‐methyl‐prop‐2‐ene is more pronounced for Boc‐NH‐Caa(R)‐D‐Ala‐OCH3 (21) and Boc‐NH‐Caa(R)‐D‐Ala‐OH (23) with Caa (R) at the N‐terminus, whereas it is totally absent for Boc‐NH‐Caa (S)‐D‐Ala‐OCH3 (22) and Boc‐NH‐Caa(S)‐D‐Ala‐OH (24) peptides, which have Caa (S) at the N‐terminus. Thus, on the basis of our previous and present studies, we propose that the CID of [M + H]+ ions provides a simple and useful method for distinguishing the configuration of Caa (S or R) at the N‐terminus of BocN‐carbo β,α‐ and β,β‐dipeptides. Copyright © 2005 John Wiley & Sons, Ltd.
Separation and online preconcentration by multistep stacking with large‐volume injection of anabolic steroids by capillary electrokinetic chromatography using charged cyclodextrins and UV‐absorption detection
Authors: Urban Pawel L. , García‐Ruiz Carmen , García Ma Ángeles , Marina Ma. Luisa
Published: October 2005

The separation of three common anabolic steroids (methyltestosterone, methandrostenolone and testosterone) was performed for the first time by capillary EKC. Different charged CD derivatives and bile salts were tested as dispersed phases in order to achieve the separation. A mixture of 10 mmol/L succinylated‐β‐CD with 1 mmol/L β‐CD in a 50 mmol/L borate buffer (pH 9) enabled the separation of the three anabolic steroids in less than 9 min. Concentration LODs, obtained for these compounds with low absorption of UV light, were ~5×10–5 mol/L. The use of online reverse migrating sample stacking with large‐volume injection (the effective length of the capillary) enabled to improve the detection sensitivity. Sensitivity enhancement factors (SEFs) ranging from 95 (for testosterone) to 149 (for methyltestosterone) were achieved by single stacking preconcentration. Then, the possibilities of multistep stacking to improve the sensitivity for these analytes were investigated. SEFs obtained by double stacking preconcentration ranged from 138 to 185, enabling concentration LODs of 2.79×10–7 mol/L (for methyltestosterone), 3.47×10–7 mol/L (for testosterone) and 3.56×10–7 mol/L (for methandrostenolone). Although online triple stacking preconcentration was achieved, its repeatability was very poor and SEFs for the studied analytes were not calculated.
Determination of some polycyclic aromatic hydrocarbons in filter tar of Turkish cigarettes
Authors: Aygün Seker Fatma
Published: October 2005

A simultaneous determination method for the analysis of benzo[a]pyrene (BaP) and dibenzo[a,h]anthracene (DahA) in the filter tar of Turkish cigarettes has been developed. The method involved (a) the extraction of BaP and DahA with n‐hexane from ACN solution in which the cigarette filters were extracted, and then (b) purification of the n‐hexane extracts by elution on an XAD‐2 column using n‐hexane/dichloromethane (9 : 1, v/v) mixture. Separation and quantitative determination of BaP and DahA in the extracts were carried out by HPLC and fluorescence detection on a C18 RP column. The calculated recoveries for BaP and DahA were found in the range of 90–100% for each extraction and clean‐up steps. Analysis of various filter tar of Turkish cigarettes showed that an average of 74.28 ng/filter of BaP and 5.24 ng/filter of DahA were present in Turkish cigarettes.
Cover Picture: Macromol. Biosci. 10/2005
Authors: Bumbu Gina‐Gabriela , Eckelt John , Wolf Bernhard A. , Vasile Cornelia
Published: October 2005

Cover: The phase separation behavior of the interpolymer complex, IPC, of hydroxypropyl cellulose and maleic acid‐styrene copolymer is strongly dependent on the experimental conditions, constant shear rate or no shear. A sizable extension of the two phase area is noticed under shear. The phase separation temperature is minimum at a composition equal to the stoichiometry of the IPC. Further details can be found in the Full Paper by G.‐G. Bumbu,* J. Eckelt, B. A. Wolf, and C. Vasile on page 936.
Chain Growth Polycondensation as a Polymer Generating Reaction in the Synthesis of Oligo(p‐phenyleneethynylene)s with Low Polydispersity
Authors: Kovalev Aleksey I. , Takeuchi Kazuhiko , Barzykin Alexander V. , Asai Michihiko , Ueda Mitsuru , Rusanov Alexander L.
Published: October 2005

Summary: The polycondensation of 1‐ethynyl‐2,5‐dihexyl‐4‐iodobenzene in the presence of 1‐ethynyl‐2,5‐dihexyl‐4‐(2‐phenylethynyl)benzene proceeds according to the mechanism of initiated chain growth polycondensation. It has allowed the synthesis of oligomers with a desired molecular weight and a narrow molecular weight distribution. The reasons for the side reaction leading to the formation of diyne compounds are revealed and the presumed mechanism is given. This opens prospects for the preparation of defectless poly(p‐phenyleneethynylene)s with required molecular weights and narrow molecular weight distributions.

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Syncope in children with Tourette's syndrome treated with guanfacine
Authors: King Allison , Harris Peter , Fritzell James , Kurlan Roger
Published: October 2005

We report on 4 children who experienced a syncopal episode while being treated with guanfacine without any other evident cause. Syncope appears to be an uncommon side effect of guanfacine and is probably due to drug‐induced hypotension or bradycardia. © 2005 Movement Disorder Society
On the uniqueness of motion of viscous gaseous stars
Authors: Secchi Paolo
Published: October 2005

The existence of solutions of the evolutionary equations of motion of a star regarded as a compressible viscous fluid with self‐gravitation, bounded by a free surface, has recently been considered [3, 4]. In this paper I study the uniqueness of the above solutions.
Non‐homogeneous non‐linear damped wave equations in unbounded domains
Authors: Racke Reinhard
Published: October 2005

We present a global existence theorem for solutions of utt − ∂iaik (x)∂ku + ut = ƒ(t, x, u, ut, ∇u, ∇ut, ∇2u), u(t = 0) = u0, u(=0)=u1, u(t, x), t ⪖ 0, xϵΩ.Ω equals ℝ3 or Ω is an exterior domain in ℝ3 with smoothly bounded star‐shaped complement. In the latter case the boundary condition u|∂Ω = 0 will be studied. The main theorem is obtained for small data (u0, u1) under certain conditions on the coefficients aik.

The Lp ‐ Lq decay rates of solutions of the linearized problem, based on a previously introduced generalized eigenfunction expansion ansatz, are used to derive the necessary a priori estimates.
Vector spherical spline interpolation—basic theory and computational aspects
Authors: Freeden Willi , Gervens Theo
Published: October 2005

Vector spherical interpolation is discussed from both the theoretical and computational points of view. The theory of vector spherical harmonics is an essential tool. An estimate is given for the absolute error of the interpolation process; an efficient algorithm is developed for the computation of a vector spherical interpoiant. The displacement boundary value problem of determining the elastic field from a finite number of discretely given displacement vectors is solved by the use of vector splines.
An implicit finite‐difference algorithm for the numerical simulation of supersonic flow over blunted bodies
Authors: El‐Seoud S. Abou , Törnig W.
Published: October 2005

In order to compute axisymmetric laminar supersonic flow we use an unsteady implicit finite‐difference scheme. This scheme solves numerically either the inviscid Euler equations or the ‘thin‐layer’ Navier‐Stokes equations. In both cases the scheme leads to large sparse non‐linear systems, which can be solved by a genuine iteration process. The convergence of this process is shown and numerical results are given.
Numerical analysis of semi‐linear parabolic systems in diffusion–reaction problems
Authors: Fayyad D. , Nassif N.
Published: October 2005

In this paper, we investigate problems of approximation for the solution of a system of coupled semi‐linear parabolic partial differential equations that model diffusion‐reaction problems in chemical engineering. Given that the solutions belong to Hs (0, ∞), we consider finite‐element approximations on bounded domains (0, R(h)) such that limh→0[R(h)] = ∞. Optimal convergence estimates are found to depend on the asymptotic behaviour of the solution and its regularity near t = 0. In the L2‐norm, they cannot exceed an order of O((;h2/t3/4) + h2[In h]2). For that purpose, a Wheeler‐type argument is also generalized to non‐coercive elliptic forms. Fully discrete schemes that preserve the positivity of the solutions are also considered. Due to the singularity at t = 0, they lead to estimates of the order O(τ1/4 + h2/t3/4).
Local compactness for linear elasticity in irregular domains
Authors: Weck Norbert
Published: October 2005

For the theory of boundary value problems in linear elasticity, it is of crucial importance that the space of vector‐valued L2‐functions whose symmetrized Jacobians are square‐integrable should be compactly embedded in L2. For regions with the cone property this is usually achieved by combining Korn's inequalities and Rellich's selection theorem. We shall show that in a class of less regular regions Korn's second inequality fails whereas the desired compact embedding still holds true.
Best constants in Korn‐Poincaré's inequalities on a slab
Authors: Ito Hiroya
Published: October 2005

We establish the best constants in the Poincaré‐type and the trace‐type inequalities for the quadratic form \documentclass{article}\pagestyle{empty}\begin{document}$ \lambda ||\,{\rm div}\,{\rm u}\,||_{L^2 }^2 \, + \,2\,\mu \,||\,\,(\nabla {\rm u}\, + \,\nabla {\rm u}^{\rm T})/2\,||_{L^2 }^2 $\end{document} which is fundamental in elasticity theory, on the space of H1 vector fields u on a slab vanishing on one or both of its sides. We similarly calculate those constants for the case of H1 divergence‐free vector fields. Our method, which is fairly general, has another practical application to the quadratic form ∑j,k(ajk∂ku, ∂ju)L2 with coefficients a jk = akj ε C in H1 scalar functions u on a slab.
A generalization of the H‐theorem to steady non‐equilibrium states. Part 1: A basic decomposition and the linear case
Authors: Triolo L.
Published: October 2005

A generalized relative entropy functional is associated to the evolution of gas in a container with (generally) non‐uniform boundary data. A decomposition for its rate in ‘bulk’ and in ‘boundary’ terms is given; for the linear case both have a definite sign. The relation with the strong L1 stability is pointed out.
Regularising discretizations of the Birkhoff‐Rott equation
Authors: Friedrich Oliver , Sonar Thomas
Published: October 2005

A thin shear layer moving from the trailing edge of a two‐dimensional aerofoil section downstream can be interpreted as a curve of discontinuity for the tangential velocity and may be approximated by a vortex sheet in inviscid, incompressible fluid flow. It is well known that vortex sheets are subject to instabilities of Kelvin‐Helmholtz type which lead to roll‐up phenomena in the wake. The motion of such sheets is governed by the Birkhoff‐Rott equation. In the case of Kelvin‐Helmholtz instability it seems clear that a curvature singularity occurs at a certain critical time and that consistent discretizations of the Birkhoff‐Rott equation may fail to yield reliable results even before the time of occurrence of a singularity. We discuss the modification of the Biot‐Savart kernel in the sense of Krasny who regularized the kernel by means of a global parameter. Using discrete Fourier transform we show the damping influence of this regularization technique. We modify the kernel carefully by introducing a regularization found in ordinary vortex methods and show that reliable results may be obtained up to and slightly after the singularity formation without increasing the accuracy of the computation.
Cloned endangered species takin (Budorcas taxicolor) by inter‐species nuclear transfer and comparison of the blastocyst development with yak (Bos grunniens) and bovine
Authors: Li Yanxin , Dai Yunping , Du Weihua , Zhao Chunjiang , Wang Haiping , Wang Lili , Li Rong , Liu Ying , Wan Rong , Li Ning
Published: October 2005

Interspecies cloning might be used as an effective method to conserve endangered species and to support the study of nuclear–cytoplasm interaction. In this study, we describe the development of takin–bovine embryos in vitro produced by fusing takin ear fibroblasts with enucleated bovine oocytes and examine the fate of mitochondrial DNA in these embryos. We also compare the blastocyst development of takin–bovine embryos with yak–bovine and bovine–bovine embryos and compare the cell numbers of the blastocyst. Our results indicate that: (1) takin–bovine cloned embryos can develop to the blastocyst stage in vitro (5%), (2) blastocyst mitochondria DNA are derived primarily from bovine oocytes in spite of a little takin donor cell mitochondrial DNA, (3) using the same cloned protocol, development efficiency is significantly different between bovine–bovine cloning, yak–bovine, and takin–bovine cloning (48 vs. 28% vs. 5%, P < 0.01), and (4) cell numbers in the blastocysts of the three species of embryos were not different. These results suggest that the bovine oocytes can reprogram the takin, yak, and bovine fibroblast nuclei. However, the development efficiency of intra‐species cloning tends to be higher than inter‐species cloning; the more close the species of the donor cell is to the recipient oocyte (yak versus takin), the greater the blastocyst development in vitro. Mol. Reprod. Dev. © 2005 Wiley‐Liss, Inc.
Morphological effects of myasthenia gravis patient sera on human muscle cells
Authors: Luckman Steven Paul , Skeie Geir Olve , Helgeland Geir , Gilhus Nils Erik
Published: October 2005

Myasthenia gravis (MG) is caused primarily by autoantibodies against the nicotinic acetylcholine receptor (AChR), but autoantibodies to other muscle proteins may be present. Many of these proteins have structural or signalling functions, the disruption of which may affect muscle cell morphology or viability. In order to investigate the role of such autoantibodies in MG, we examined the effect of MG patient sera, of different autoantibody composition and obtained at different stages of disease severity, on primary human muscle cells. Sera from MG patients induced changes in cell morphology from typical elongated cells to an irregular phenotype, caused the formation of inclusion bodies and intracellular vesicles, and led to a disordered arrangement of actin microfilaments. Sera from the most severely affected patients also induced cell death, which did not occur via classic apoptosis. The effects were not complement‐mediated and were dose‐ and time‐dependent. As the effects observed in the cell culture system correlated with disease severity, a greater understanding of the individual factors responsible for these effects may improve our understanding of MG pathogenesis and be of value in the assessment of disease in individual patients. Muscle Nerve, 2005
Comparison of the urethral properties of the female guinea pig and rat
Authors: Walters Richard David , McMurray Gordon , Brading Alison Frances
Published: October 2005

Aims

The main focus of this study was to profile and compare urethral function in the female guinea pig and rat, and to characterize urodynamically distinctive patterns in the micturition cycle of the two species. This exercise aimed to investigate potential species‐related differences and determine a suitable animal model for the human urethra.

Materials & Methods

Female Dunkin–Hartley guinea pigs (400–500 g) and Sprague‐Dawley rats (200–300 g) were used throughout the study. For in vitro experiments urethral rings were suspended vertically for isometric tension recording in 5 ml organ baths and drugs (phenylephrine 10−4 M and carbachol 10−4 M) were applied directly to the bathing solution. In vivo urethral pull‐through and urodynamic studies were performed under urethane anesthesia, and phenylephrine (200 µg/kg) was administered during urethral pull‐through experiments via the intravenous (i.v.) route. Urethral, bladder and arterial pressures, and external urethral sphincter electromyographic (EMG) spike activity were recorded simultaneously throughout.

Results

Organ bath studies coupled with in vivo pull‐through experiments produced urethral profiles with distinct regional variations for both species. Urodynamic studies with the urethral probe fixed in the high pressure zones of the proximal urethra produced similar recordings in both species during bladder filling and marked differences during micturition. The guinea pig showed complete sphincteric inhibition immediately prior and during micturition as also seen in the human, whereas the rat exhibited high frequency bursts in EMG activity at this stage in the cycle.

Conclusions

The EMG activity seen in the rat during micturition is presumably necessary for efficient voiding, thus the guinea pig is a more suitable comparative model for the human in relation to urethral properties during micturition. Neurourol. Urodynam. © 2005 Wiley‐Liss, Inc.
A comparison of some domain decomposition and ILU preconditioned iterative methods for nonsymmetric elliptic problems
Authors: Cai Xiao‐Chuan , Gropp William D. , Keyes David E.
Published: October 2005

In recent years, competitive domain‐decomposed preconditioned iterative techniques of Krylov‐Schwarz type have been developed for nonsymmetric linear elliptic systems. Such systems arise when convection‐diffusion‐reaction problems from computational fluid dynamics or heat and mass transfer are linearized for iterative solution. Through domain decomposition, a large problem is divided into many smaller problems whose requirements for coordination can be controlled to allow effective solution on parallel machines. A central question is how to choose these small problems and how to arrange the order of their solution. Different specifications of decomposition and solution order lead to a plethora of algorithms possessing complementary advantages and disadvantages. In this report we compare several methods, including the additive Schwarz algorithm, the classical multiplicative Schwarz algorithm, an accelerated multiplicative Schwarz algorithm, the tile algorithm, the CGK algorithm, the CSPD algorithm, and also the popular global ILU‐family of preconditioners, on some nonsymmetric or indefinite elliptic model problems discretized by finite difference methods. The preconditioned problems are solved by the unrestarted GMRES method. A version of the accelerated multiplicative Schwarz method is a consistently good performer.
Thermal stress evaluation in the steel continuous casting process
Authors: Risso J. M. , Huespe A. E. , Cardona A.
Published: October 2005

Two numerical models for the thermal stress and plastic strain analysis in the solid shell at the initial stage of a steel continuous casting process, are presented and their performances evaluated. First, a numerical procedure based on a natural extension of the semi‐analytical study proposed by Weiner and Boley (J. Mech. Phys. Solids 1963; 11:145–154) is introduced and validated by comparison with their semi‐analytical 1‐D solution. The basic hypotheses of this model, and particularly the extended plane strain condition with uniform axial strain, are afterwards tested in more complex and realistic situations by comparing results with those obtained by an alternative numerical scheme presented by Fachinotti (Doctoral Thesis, Universidad Nac. Litoral, Argentina, 2001) and Fachinotti and Cardona (Internal Report, CIMEC, sent to IJNME, 2002). Finally, results of a typical and representative 3D simulation, corresponding to a slab continuous casting process, are shown. Copyright © 2005 John Wiley & Sons, Ltd.
Trefftz solutions for piezoelectricity by Lekhnitskii's formalism and boundary‐collocation method
Authors: Sheng N. , Sze K. Y. , Cheung Y. K.
Published: October 2005

In this paper, a solution procedure for plane piezoelectricity is developed by Trefftz boundary‐collocation method. Starting with the general plane piezoelectricity solution derived by Lekhnitskii's formalism, the basic sets of Trefftz functions which satisfy the homogeneous governing equations are derived. Moreover, special sets of Trefftz functions are derived for impermeable elliptical voids, impermeable sharp cracks and permeable sharp cracks with arbitrary orientations with respect to the material poling direction. The functions in the special sets satisfy not only the homogeneous governing equations but also the boundary conditions at the peripheries of the pertinent defects. By adopting Trefftz functions as the trial functions, multi‐domain Trefftz boundary‐collocation method is formulated. Numerical examples are presented to illustrate the efficacy of the formulation. Copyright © 2005 John Wiley & Sons, Ltd.
A generalized non‐linear transformation for evaluating singular integrals
Authors: Yun Beong In
Published: October 2005

In this paper, we propose a function which, according to a parameter included therein, generates a new sigmoidal transformation and converges to the well‐known Sato polynomial transformation. Following well‐established procedures in the literature, we employ the present transformation in the numerical evaluation of weakly singular integrals, Cauchy principal value integrals and Hadamard finite‐part integrals.

By several numerical examples it is shown that the present transformation is available for all kinds of singular integrals mentioned above and, in some cases, gives better results compared with those of traditional non‐linear transformations. Copyright © 2005 John Wiley & Sons, Ltd.
An iterative procedure for the oscillatory laminar boundary layer
Authors: Newton S. G.
Published: October 2005

The problem of small sinusoidal oscillations imposed on a stagnation point flow is considered. This leads to an ordinary differential equation which, in the high frequency limit, has a simple solution. An iterative method (involving a linear integral operator) is developed, starting from this basic solution. This scheme, performed numerically, is ‘under‐relaxed’ and this renders it applicable to as wide a frequency range as possible: convergence criteria are discussed in terms of the relaxation parameter. The streamwise velocity profiles computed are compared with those given by an independent method.
Finite elements with penalties in nonlinear elasticity
Authors: Malkus David S.
Published: October 2005

This paper describes the use of a penalty method to enforce the constraint of incompressibility in nonlinear elasticity. As an example, a problem involving the use of the Newton–Raphson method in conjunction with incremental loading and a successive mesh refinement scheme is presented. It is shown that during the incremental loading phase and the Newton–Raphson refinement on a fixed mesh, all tangent stiffness matrices are positive definite for the chosen energy density and load increment. But when the mesh is refined and the solution is interpolated as a starting value on the new mesh, the tangent stiffness matrix is indefinite. A theoretical analysis of the associated mixed method and a new equivalence theorem are seen to lead to a way to retain positive definiteness. The key is the use of an equivalent tangent stiffness matrix which is the reduced Hessian matrix. The numerical example shows that both positive definiteness and the quadratic convergence rate of the Newton–Raphson method are obtained.
Galerkin and collocation‐Galerkin methods with superconvergence and optimal fluxes
Authors: Carey G. F. , Humphrey D. , Wheeler M. F.
Published: October 2005

Finite element methods are formulated and investigated for the effectiveness factor problem for heat and mass transfer with chemical reactions in catalyst pellet models. A Galerkin finite element method is compared with a previous C1 collocation method7. A scheme that is conceptually intermediate between these two methods and accordingly has been termed collocation‐Galerkin is formulated and numerical experiments considered. Of particular interest here are superconvergence results at the Gauss and Jacobi points, respectively. Numerical studies of superconvergence in the presence of a nonlinear reaction‐rate term are presented. An integral formula is devised and used to compute the flux at the pellet surface to optimal accuracy. Numerical experiments are conducted to demonstrate the improvement in computed fluxes.
Stress evaluation algorithms for rate constitutive equations in finite deformation analysis
Authors: Lo S. H.
Published: October 2005

The stress integration algorithm for hypoelastic constitutive equations proposed by Pinsky et al.3 is extended for the treatment of finite deformation elastoplastic constitutive relations. Another approach based on the polar decomposition of the deformation gradient tensor F = R · U is also introduced. Numerical examples and a discussion on these two approaches are given.
A hybrid strain finite element for plates and shells
Authors: Bergmann V. L. , Mukherjee S.
Published: October 2005

This paper describes a new hybrid strain finite element for geometrically linear analysis of plates and shells. The formulation for materially linear problems is based on a mixed variational principle having strain and displacement rates as independently varied fields. To facilitate extension to materially non‐linear analysis, the variational principle is used in rate form and the plane stress assumption is not imposed a priori in the formulation. When desired, the plane stress assumption is imposed in a manner similar to imposition of fixed boundary conditions. The element geometry is based on a nine‐noded quadrilateral with biquadratic interpolation of the displacement field. The strain field is based on a bilinear interpolation with additional non‐linear terms, chosen on the basis of eigenvalue analysis. The element passes the required patch tests, does not display either membrane or shear locking effects, and is free of communicable spurious modes. Numerical results are presented for elastic analyses of several standard plate and shell test problems.
A hybrid optimal synthesis method for truss structures considering shape, material and sizing variables
Authors: Ohkubo Sadaji , Asai Kazuhiro
Published: October 2005

A generalized hybrid optimal synthesis method is developed for truss structures in which the design variables are the co‐ordinates of the panel points, cross‐sectional areas and discrete material kinds of member elements. The primary design problem is formulated in terms of the shape, material and sizing variables and approximated to a sequence of convex and separable subproblems by using mixed direct/reciprocal design variables. Each subproblem is solved by a dual method in which the continuous shape and sizing variables are optimized by a Newton‐type algorithm and the discrete material and continuous sizing variables are improved by a discrete sensitivity analysis. Using the proposed method, discrete material kinds, shape and sizing variables can be systematically improved to obtain an optimum solution. The rigourness, reliability and efficiency of the method are demonstrated by applying it to the minimum cost design of trusses subjected to stress and displacement constraints.
An adaptive finite element procedure for 2D dynamic transient analysis using direct integration
Authors: Zeng L. F. , Wiberg N.‐E. , Bernspång L.
Published: October 2005

An adaptive h‐version finite element procedure is presented for a 2D elastodynamic transient analysis using direct integration. The procedure modifies the spatial discretization, i.e. the mesh, in time so that the spatial discretization error can be controlled in each time instant. We analyse an a priori error estimate for the total energy which shows that an a posteriori error estimate developed by Zienkiewicz and Zhu for linear elastostatics can reasonably be extended to dynamic transient analysis. For the time integration, both explicit and implicit time integration schemes can be coupled with the procedure. However, the study in this paper is confined to the use of the Newmark scheme. Numerical examples are used to study the performance of the error estimate and to illustrate the adaptive procedure. Obtained numerical results indicate that: (i) the extension of the Zienkiewicz–Zhu estimate to dynamic transient analysis is useful; (ii) the presented adaptive procedure can, in an efficient way, provide a finite element solution with a user‐controlled accuracy.
A note on the grid movement induced by MFE
Authors: Zegeling P. A. , Blom J. G.
Published: October 2005

Moving‐grid methods in one space dimension have become popular for solving several kinds of parabolic and hyperbolic partial differential equations (PDEs) involving fine scale structures such as steep moving fronts and emerging steep layers, pulses, shocks, etc. In two space dimensions, however, application of moving‐grid methods is less trivial than in 1D. For some methods, e.g. those based on equidistributing principles, it is not even clear how to extend the underlying grid selection procedure to 2D. The moving‐finite‐element (MFE) method does not suffer from this drawback; its mathematical extension to 2D is trivial. However, because of the intrinsic coupling between the discretization of the PDE and the grid selection, the application of MFE, as for any other method, is not without difficulties. In this paper we describe the node movement induced by MFE for various PDEs and we indicate some problems concerning the grid structure that can result from this movement.
Viscous heating in forced convective heat transfer across a circular cylinder at low reynolds number
Authors: Sunden Bengt
Published: October 2005

The influence of viscous heating on forced convective heat transfer from a circular cylinder in cross flow is investigated numerically. The Reynolds number is in the range of 5–40 and the Prandtl number is 0.72, corresponding to air. The Navier–Stokes equations and the continuity equations are solved in two dimensions using the streamfunction‐vorticity formulation. In the energy equation the dissipation of mechanical energy into thermal energy is taken into account. All equations are cast into a non‐dimensional form. The numerical solution procedure is based on second‐order finite difference approximations and an implicit formulation is employed. The far field boundary conditions of the flow field are satisfied by matching to asymptotic solutions. The resulting algebraic equations are solved by an iterative relaxation technique. In particular, temperature distributions for an adiabatic wall boundary condition are presented.
A finite element approach to kinetic energy discretization of deformable bodies in quasi‐rigid motion
Authors: Lucibello P. , D'Ambrogio W.
Published: October 2005

In this paper a finite element technique for the discretization of kinetic energy of bodies subjected to large rigid motion and small deformation (which we refer to as quasi‐rigid motion) is presented. First, on the basis of a separation between the rigid displacement and the deformation, the relevant kinematic relationships are derived. A standard assumed‐mode approach is used to describe the deformation displacement field by a linear combination of known functions. Then, the computation of the kinetic energy leads to the definition of a set of tensors, which are configuration‐independent (like the mass matrix in a linear setting) and fully characterize the body non‐linear dynamic behaviour introduced by large rotation. A computer code has been developed, in order to extend an existing FE package, for the computation of these tensors. Details of the technique, including storage requirements and suggestions for model reduction, are given. Finally, two examples are presented: (i) the result of the computation of one of the introduced tensors; (ii) the development of the non‐linear model of a rotating beam.
A possible case of surgical treatment of cranial blunt force injury from medieval England
Authors: Mays S. A.
Published: October 2005

A possible example of surgical treatment of depressed fracture of the cranium is presented. The individual involved is a medieval peasant from Wharram Percy. The burial dates from the 10th–11th century AD. The surgery appears to have involved the use of trepanation by the scraping technique. This case pre‐dates the first documentary descriptions in the medieval West of similar operations to treat cranial fracture, and shows that access to complex surgical treatment was not invariably the preserve of the wealthy in medieval England. Copyright © 2005 John Wiley & Sons, Ltd.
Diameter of the human internal acoustic meatus and sex determination
Authors: Lynnerup N. , Schulz M. , Madelung A. , Graw M.
Published: October 2005

We report the results of testing the diameter of the internal opening of the acoustic canal in the petrous part of the temporal bone for sex determination of skeletal remains. The method involves measuring the diameter using a suite of ordinary drills. The method is very simple and has the great advantage of utilising one of the sturdiest bone elements of the human skeleton. The method may be especially useful for the analyses of very fragmented skeletal remains or cremated bones, where the petrous bone may still be readily recognisable. The method was tested using a forensic sample of 113 left petrous bones with known sex. Intra‐ and inter‐observer testing was also performed. We found a statistically significant difference in diameter between males and females (means: males: 3.7 mm; females: 3.4 mm; P < 0.009). However, the low predictive value (70%) for correct sexing using two sectioning points ( < 3.0 mm = female; >3.5 mm = male) was disappointing. No additional accuracy was gained by employing both left and right petrous bones (a bilateral sample of 60 petrous bones was also tested), although left and right side diameter is highly correlated (R = 0.778; P = 0.0001). Copyright © 2005 John Wiley & Sons, Ltd.