bluuebunny/crossref_metadata_2025_split huggingface dataset:
Direct comparison of 3D spiral vs. Cartesian gradient‐echo coronary magnetic resonance angiography
Authors: Börnert Peter , Stuber Matthias , Botnar René M. , Kissinger Kraig V. , Koken Peter , Spuentrup Elmar , Manning Warren J. 
Published: August 2002

AbstractWhile 3D thin‐slab coronary magnetic resonance angiography (MRA) has traditionally been performed using a Cartesian acquisition scheme, spiral k‐space data acquisition offers several potential advantages. However, these strategies have not been directly compared in the same subjects using similar methodologies. Thus, in the present study a comparison was made between 3D coronary MRA using Cartesian segmented k‐space gradient‐echo and spiral k‐space data acquisition schemes. In both approaches the same spatial resolution was used and data were acquired during free breathing using navigator gating and prospective slice tracking. Magnetization preparation (T2 preparation and fat suppression) was applied to increase the contrast. For spiral imaging two different examinations were performed, using one or two spiral interleaves, during each R‐R interval. Spiral acquisitions were found to be superior to the Cartesian scheme with respect to the signal‐to‐noise ratio (SNR) and contrast‐to‐noise‐ratio (CNR) (both P < 0.001) and image quality. The single spiral per R‐R interval acquisition had the same total scan duration as the Cartesian acquisition, but the single spiral had the best image quality and a 2.6‐fold increase in SNR. The double‐interleaf spiral approach showed a 50% reduction in scanning time, a 1.8‐fold increase in SNR, and similar image quality when compared to the standard Cartesian approach. Spiral 3D coronary MRA appears to be preferable to the Cartesian scheme. The increase in SNR may be “traded” for either shorter scanning times using multiple consecutive spiral interleaves, or for enhanced spatial resolution. Magn Reson Med 46:789–794, 2001. © 2001 Wiley‐Liss, Inc.
EPR oxygen mapping (EPROM) of engineered cartilage grown in a hollow‐fiber bioreactor
Authors: Ellis Scott J. , Velayutham M. , Velan S. Sendhil , Petersen Erik F. , Zweier Jay L. , Kuppusamy Periannan , Spencer Richard G.S. 
Published: August 2002

AbstractA novel electron paramagnetic resonance (EPR)‐based oxygen mapping procedure (EPROM) is applied to cartilage grown in a single‐, hollow‐fiber bioreactor (HFBR) system. Chondrocytes harvested from the sterna of 17‐day‐old chick embryos were inoculated into an HFBR and produced hyaline cartilage over a period of 4 weeks. Tissue oxygen maps were generated according to the EPROM technique (Velan et al., Magn Reson Med 2000;43:804–809) by making use of the line‐broadening effects of oxygen on the signal generated from nitroxide spin probes. In addition, the effect on oxygen consumption of the addition of cyanide to the tissue was investigated. Cyanide is a potent inhibitor of oxidative phosphorylation, and accordingly, given the constant provision of oxygen to the tissue, it would be expected to increase oxygen levels within the HFBR. The EPROM measurements showed a significant increase in oxygen concentration in the cartilage after the addition of cyanide. In contrast to other methods for studying oxygen in cartilage, EPROM can provide direct, noninvasive visualization of local concentrations in three dimensions. Magn Reson Med 46:819–826, 2001. © 2001 Wiley‐Liss, Inc.
Gd‐DTPA2–‐enhanced MRI of femoral knee cartilage: A dose‐response study in healthy volunteers
Authors: Tiderius Carl J. , Olsson Lars E. , de Verdier Hans , Leander Peter , Ekberg Olle , Dahlberg Leif 
Published: August 2002

AbstractThe negatively charged contrast agent Gd‐DTPA2– distributes inversely to the cartilage fixed charged density. This enables structural cartilage examinations by contrast‐enhanced MRI. In line with the development of a clinically applicable protocol for such examinations, this study describes the temporal pattern of Gd‐DTPA2– distribution in femoral knee cartilage at three different doses in healthy volunteers. Nineteen volunteers (ages 21–28 years) were examined with a 1.5T MRI system. Quantitative relaxation rate measurements were made in weight‐bearing central parts of femoral cartilage using sets of five turbo inversion recovery images with different inversion times. The cartilage was analyzed before and four times (1–4 h) after an intravenous injection of Gd‐DTPA2– at single, double, and triple doses: 0.1, 0.2, and 0.3 mmol/kg body weight, respectively. The increase in R1 postcontrast was linearly dose‐related at all times. The highest R1 values were registered at 2 and 3 h postcontrast, suggesting 2 h to be optimal in the clinical situation. The triple dose indicated a subtle compartmental difference in men, with higher contrast distribution medially than laterally. Results suggest that the triple dose is needed to detect minor cartilage matrix differences. Magn Reson Med 46:1067–1071, 2001. © 2001 Wiley‐Liss, Inc.
Intravascular lymphomatosis
Authors: Oei Melina E. , Kraft George H. , Sarnat Harvey B. 
Published: August 2002

AbstractIntravascular lymphomatosis, also known as endovascular lymphoma or angiotropic large cell lymphoma, is a rare malignancy typically diagnosed at autopsy. We describe a case in which the diagnosis was made at an early stage. Specific electrodiagnostic findings suggested concomitant polyneuropathy and myopathy. Suspicion of a paraneoplastic syndrome during electrodiagnostic testing prompted muscle biopsy, which revealed myopathy due to the direct infiltration of neoplastic cells. Resultant treatment with a standard chemotherapy regimen not only increased the patient's survival, but also improved neurological function. © 2002 Wiley Periodicals, Inc. Muscle Nerve 25:000–000, 2002
Deformations caused by the movements of shear and tensile faults
Authors: Sheu Guang Y. 
Published: August 2002

AbstractEarlier solutions of deformations resulting from the movements of shear and tensile faults in a half space (Bull. Seismol. Soc. Amer. 1985; 75:1135, 1992; 82:1018) have been revised in view of cross‐anisotropic stress–strain relationships. The dislocation theory (Canad. J. Phys. 1958; 36:192) is reviewed and the displacement field due to a concentrated force in an anisotropic half space is solved analytically for developing the current research. A fault is simulated as a point source of strain nuclei in applying the dislocation theory.Data (Terr. Atmos. Oceanic Sci. 2000; 11(3):591, 631) that were used to study the Chi‐Chi earthquake (ML=7.3; 1999/9/21 AM 1:47) are introduced to compare the solution with the isotropic results. Results indicate that the anisotropy of stress–strain relationships does affect the results of predicted deformations. Copyright © 2001 John Wiley & Sons, Ltd.
Performance of Jacobi preconditioning in Krylov subspace solution of finite element equations
Authors: Lee F.‐H. , Phoon K.K. , Lim K.C. , Chan S.H. 
Published: August 2002

AbstractThis paper examines the performance of the Jacobi preconditioner when used with two Krylov subspace iterative methods. The number of iterations needed for convergence was shown to be different for drained, undrained and consolidation problems, even for similar condition number. The differences were due to differences in the eigenvalue distribution, which cannot be completely described by the condition number alone. For drained problems involving large stiffness ratios between different material zones, ill‐conditioning is caused by these large stiffness ratios. Since Jacobi preconditioning operates on degrees‐of‐freedom, it effectively homogenizes the different spatial sub‐domains. The undrained problem, modelled as a nearly incompressible problem, is much more resistant to Jacobi preconditioning, because its ill‐conditioning arises from the large stiffness ratios between volumetric and distortional deformational modes, many of which involve the similar spatial domains or sub‐domains. The consolidation problem has two sets of degrees‐of‐freedom, namely displacement and pore pressure. Some of the eigenvalues are displacement dominated whereas others are excess pore pressure dominated. Jacobi preconditioning compresses the displacement‐dominated eigenvalues in a similar manner as the drained problem, but pore‐pressure‐dominated eigenvalues are often over‐scaled. Convergence can be accelerated if this over‐scaling is recognized and corrected for. Copyright © 2002 John Wiley & Sons, Ltd.
Partial unilateral ureteral obstruction in rats
Authors: Wen Jian Guo 
Published: August 2002

AbstractThis review comprises an overview of the current knowledge on experimental partial unilateral ureteral obstruction (PUUO) and a summary of our latest original experimental PUUO studies in rats. Neonatal PUUO is the type of obstruction that is most often encountered in pediatric clinical practice. However, the pathogenesis of PUUO is still incompletely understood. Most of our knowledge on PUUO has been derived from experimental studies in a variety of animal models. Although progress has been made, the natural history of congenital hydronephrosis is still incompletely described. The effects on kidney functions of long‐term urinary tract obstruction, especially PUUO, have been less intensively studied. Recently, we created models with mild and severe PUUO in young rats by embedding the upper one fourth or the upper two thirds of the left ureter into the psoas muscle, respectively. Thereafter, the technique was used to create mild and severe PUUO in newborn rats and magnetic resonance imaging studies showed that both mild and severe obstruction caused a time‐dependent decrease in renal blood flow. Compensatory increase in total kidney volume and renal vein blood flow in contralateral non‐obstructed kidneys was not detectable when functional deterioration in the partially obstructed kidneys was present. Finally, we investigated the dynamic changes in renal relative signal intensity (RSI) of gadolinium‐diethylenetriamine pentaacetic acid (Gd‐DTPA) using magnetic resonance imaging in rats with partial, complete unilateral ureteral obstruction and sham‐operated controls. The results showed that changes in Gd‐DTPA RSI are compatible with the known physiological and anatomical changes in kidneys in response to ureteral obstruction and useful for distinguishing an obstructed from a non‐obstructed collecting system and also for differentiating a partially obstructed from a completely obstructed collecting system. Neurourol. Urodynam. 21:231–250, 2002. © 2002 Wiley‐Liss, Inc.
Urinary dysfunction in Brown‐Séquard syndrome
Authors: Sakakibara Ryuji , Hattori Takamichi , Uchiyama Tomoyuki , Yamanishi Tomonori 
Published: August 2002

AbstractBrown‐Séquard syndrome (BS) is a rare but well documented condition of the spinal cord hemisection, comprising hemiparesis with crossed superficial sensory disturbance. However, little is known of micturitional function in BS, although some patients with BS are troubled with severe voiding difficulty and urinary incontinence. We performed urinary questionnaire and urodynamic studies in eight patients with BS, including seven men and one woman, mean age of 41 years. Detailed questionnaire showed that five of the eight patients (63%) had micturitional symptoms, including voiding difficulty in three, urinary retention in two, urinary frequency in two and urge urinary incontinence in one. Urodynamic abnormalities were noted in all five patients with micturitional symptoms, including post‐micturition residuals in four (average 149 mL), high urethral closure pressure in two, increased bladder volume at first sensation in one, detrusor hyperreflexia in four, detrusor areflexia on voiding in three and unrelaxing sphincter on voiding in four. Three asymptomatic patients showed normal urodynamic finding. Micturitional symptoms were more common in patients with severe motor paresis (100%) than in those with mild motor paresis (40%), and there was no relation between micturitional disturbance with superficial or deep sensory disturbance. A combination of treatments for the underlying disorders with α‐adrenergic blocking agent and clean, intermittent self‐catheterization ameliorated the urinary dysfunction in all patients together with neurological dysfunction. In conclusion, micturitional disturbance was not uncommon in our patients with BS, particularly in those with severe motor paresis, which could ameliorate by appropriate therapies. Neurourol. Urodynam. 20:661–667, 2001. © 2001 Wiley‐Liss, Inc.
Development of a low‐cost flow meter to grade the maximum flow rate
Authors: Pel J.J.M. , van Mastrigt R. 
Published: August 2002

AbstractWe developed an inexpensive flow meter to grade the maximum flow rate of individuals at locations other than the clinical setting. This flow meter consists of a funnel connected to a collecting tube with several exit ports. Urine directed into this tube flows through one or more ports and is collected in a measuring cup to measure the voided volume. The number of ports emitting the liquid is a measure for the flow rate. We made four experimental models to test and compare some of the physical properties. One of these models was selected as a prototype and was tested in five healthy volunteers. All volunteers voided repeatedly in a standard rotating disk flow meter and in this prototype to test its accuracy. The response time of the experimental models depended on the outlet resistance of the exit ports and the volume of the collecting tube. In two models, this time was comparable with that of currently used volume‐based electronic flow meters (∼2 seconds). In healthy volunteers, the maximum flow rates graded with the selected prototype and those measured with the rotating disk flow meter showed good agreement (difference=0.4 ± 2.6 mL/s; mean ± SD). The low‐cost flow meter may be used repeatedly to grade the maximum flow rate at private and familiar locations (for example, at home), which may increase the accuracy of evaluating the urinary stream in patients with lower urinary tract symptoms. Neurourol. Urodynam. 21:48–54, 2002. © 2002 Wiley‐Liss, Inc.
Service differentiation using a multi‐level RED mechanism
Authors: Aweya James , Ouellette Michel , Montuno Delfin Y. 
Published: August 2002

AbstractThis paper describes a multi‐level active queue management scheme that combines packet classification and random early detection (RED) capabilities to provide differentiated performance characteristics for different classes of service. The proposed RED scheme uses a simple control‐theoretic algorithm to randomly discard packets with a load‐dependent probability when a buffer in a router gets congested. Copyright © 2002 John Wiley & Sons, Ltd.
Forked end: a novel transmembrane protein involved in neuromuscular specificity in drosophila identified by gain‐of‐function screening
Authors: Umemiya Takeshi , Takasu Etsuko , Takeichi Masatoshi , Aigaki Toshiro , Nose Akinao 
Published: August 2002

AbstractThe Drosophila neuromuscular connectivity provides an excellent model system for studies on target recognition and selective synapse formation. To identify molecules involved in neuromuscular recognition, we conducted gain‐of‐function screening for genes whose forced expression in all muscles alters the target specificity. We report here the identification of a novel transmembrane protein, Forked end (FEND), encoded by the fend gene, by the said screening. When the FEND expression was induced in all muscles, motoneurons that normally innervate muscle 12 formed ectopic synapses on a neighboring muscle 13. The target specificity of these motoneurons was also altered in the loss‐of‐function mutant of fend. During embryonic development, fend mRNA was detected in a subset of cells in the central nervous system and in the periphery. These results suggest that FEND is a novel axon guidance molecule involved in neuromuscular specificity. © 2002 Wiley Periodicals, Inc. J Neurobiol 51: 205–214, 2002
On the solution of large Sylvester‐observer equations
Authors: Calvetti D. , Lewis B. , Reichel L. 
Published: August 2002

AbstractThe design of a Luenberger observer for large control systems is an important problem in Control Theory. Recently, several computational methods have been proposed by Datta and collaborators. The present paper discusses numerical aspects of one of these methods, described by Datta and Saad (1991). Copyright © 2001 John Wiley & Sons, Ltd.
A numerically scalable domain decomposition method for the solution of frictionless contact problems
Authors: Dureisseix D. , Farhat C. 
Published: August 2002

AbstractWe present a domain decomposition method with Lagrange multipliers for solving iteratively frictionless contact problems. This method, which is based on the FETI method and therefore is named here the FETI‐C method, incorporates a coarse contact system that guides the iterative prediction of the active zone of contact. We demonstrate numerically that this method is numerically scalable with respect to both the problem size and the number of subdomains. Copyright © 2001 John Wiley & Sons, Ltd.
An algorithm and a method to search bifurcation points in non‐linear problems
Authors: Chambon R. , Crochepeyre S. , Charlier R. 
Published: August 2002

AbstractThis paper is devoted to a numerical method able to help the determination of the bifurcation threshold in non‐linear time‐independent continuum mechanic problems. First, some theoretical results about uniqueness are recalled. In the framework of the large‐strain assumption, the differences between the classical finite‐step problem and the rate problem are presented. An iterative algorithm able to solve the rate problem is given. Using different initializations, it is seen in some numerical experiments that it is possible with this algorithm to get different solutions when the underlying mathematical problem solved does not enjoy a uniqueness property. The constitutive equations used have been chosen to be simple enough to deduce some theoretical knowledge about the corresponding uniqueness problems. Finally, a method is given which is able in some case to give an upper bound of the bifurcation threshold. Copyright © 2001 John Wiley & Sons, Ltd.
Time‐ and space‐adaptive methods applied to localization phenomena in empty and saturated micropolar and standard porous materials
Authors: Ehlers W. , Ellsiepen P. , Ammann M. 
Published: August 2002

AbstractLocalization phenomena, as e.g. shear bands, occur as a result of local concentrations of plastic strains in small bands of finite width. The reason for this behaviour lies in the basic properties of elasto‐plastic frictional materials, where variations of the Lode angle together with the non‐associated plastic dilatation result in local softening effects. Proceeding from non‐viscous empty porous materials, it is well known that the computation of shear bands reveals an ill‐posed problem. To overcome this behaviour, two different regularization strategies are considered, which are (1) the inclusion of independent rotational degrees of freedom (micropolar formulation) and (2) the inclusion of viscosity effects (standard formulation) by taking into consideration viscoplastic properties of the solid matrix or a viscous pore‐fluid, respectively. The numerical treatment furthermore proceeds from time‐ and space‐adaptive strategies to refine and to coarsen both the time step and the mesh size. Considering quasi‐static problems, the space discretization yields a DAE system of index 1 in the time domain which can be successfully treated by SDIRK methods, thus allowing for an efficient estimation of the time error and, as a consequence, for an adaptive time‐step control. In the space domain, the present investigation proceeds from an error indicator of Zienkiewicz‐Zhu type, where smoothened values of the L2‐norms of characteristic quantities are compared to the respective discrete values. The efficiency of this procedure is demonstrated by the computation of the biaxial experiment on an empty and a liquid‐saturated porous soil material and of the slope failure problem of a fluid‐saturated soil. Copyright © 2001 John Wiley & Sons, Ltd.
Some nonconforming mixed box schemes for elliptic problems
Authors: Croisille Jean‐Pierre , Greff Isabelle 
Published: August 2002

AbstractIn this article, we introduce three schemes for the Poisson problem in 2D on triangular meshes, generalizing the FVbox scheme introduced by Courbet and Croisille [1]. In this kind of scheme, the approximation is performed on the mixed form of the problem, but contrary to the standard mixed method, with a pair of trial spaces different from the pair of test spaces. The latter is made of Galerkin‐discontinuous spaces on a unique mesh. The first scheme uses as trial spaces the P1 nonconforming space of Crouzeix‐Raviart both for u and for the flux p = ∇u. In the two others, the quadratic nonconforming space of Fortin and Soulie is used. An important feature of all these schemes is that they are equivalent to a first scheme in u only and an explicit representation formula for the flux p = ∇u. The numerical analysis of the schemes is performed using this property. © 2002 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq 18: 355–373, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/num.10003
Adequacy of finite difference schemes for convection‐diffusion equations
Authors: Shapira Yair 
Published: August 2002

AbstractFinite difference schemes for the numerical solution of singularly perturbed convection problems on uniform grids are studied in the limit case where the viscosity and the meshsize approach zero at the same time. The present error estimates are given in terms of order of magnitude in the above limit process and are useful in a priori choosing adequate schemes and meshsizes for boundary‐layer problems and problems with closed characteristics. Published 2002 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq 18: 280–295, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/num.10007
Acrylate terpolymer in fabrication of medicated skin patches
Authors: Mare Vibha S. , Bharti Prasad V. , Vavia Pradeep R. 
Published: August 2002

AbstractAn acrylate based pressure sensitive adhesive (PSA) was synthesized to design a drug‐in‐adhesive (DIA) type transdermal therapeutic system (TTS) for nitroglycerin used in the treatment of angina pectoris. 2‐Ethylhexyl acrylate (EHA), methyl methacrylate (MMA) and acrylic acid (AA) were used to synthesize the PSA by free radical solution polymerization. The effects of reaction time, reaction temperature, initiator concentration and solvent on polymerization were studied. The synthesized terpolymer was characterized by 1H‐NMR, FT‐IR, differential scanning calorimetry (DSC) and gel permeation chromatography (GPC) and also evaluated for intrinsic viscosity, refractive index, peel strength, moisture uptake and skin irritation potential. The PSA was used to develop DIA type patches of nitroglycerin. The patches were cast using solvent evaporation technique and dried at controlled temperature. The patches were evaluated for thickness uniformity, weight variation, peel strength and moisture pick‐up. The percent drug content and in vitro drug release was determined by high pressure liquid chromatography (HPLC) method. On the basis of in vitro release profile, patches were selected for in vitro skin permeation studies. The developed formulation TP‐1 (K = 24.892 mcg/cm2/hr) followed zero‐order rate kinetics and showed better skin permeation rate in comparison to the marketed TTS (MTTS) (K = 17.413 mcg/cm2/hr). TP‐1 was subjected to stability testing for a period of 1 year according to ICH guidelines. The patches were found to be stable and an expiry date of 2 years was predicted with storage at 25 °C or below. Copyright © 2001 John Wiley & Sons, Ltd.