bluuebunny/crossref_metadata_2025_split huggingface dataset:
In vivo measurement of regional oxygenation and imaging of redox status in RIF‐1 murine tumor: Effect of carbogen‐breathing
Authors: Ilangovan Govindasamy , Li Haiquan , Zweier Jay L. , Krishna Murali C. , Mitchell James B. , Kuppusamy Periannan 
Published: October 2002

AbstractThe purpose of this study was to noninvasively monitor tumor oxygenation and redox status during hyperoxygenation treatment, such as carbogen‐breathing, in a murine tumor model using in vivo electron paramagnetic resonance (EPR) spectroscopy and imaging techniques. The study was performed using implanted lithium phthalocyanine (LiPc) microcrystals as the oximetry probe and 3‐carbamoylproxyl (3‐CP) as the redox probe in RIF‐1 tumors implanted in the upper hind leg of C3H mice. Repetitive measurements of pO2 from the same tumors as a function of tumor growth (8–24 mm in size) showed that the tumors were hypoxic and that the tumor pO2 values were decreasing with tumor growth. Carbogen‐breathing mostly showed an increase in the tumor oxygenation, although there were considerable variations in the magnitude of change among the tumors. The pharmacokinetic studies with 3‐CP showed a significant decrease in the overall tumor reduction status in the carbogen‐breathing mice. Spatially resolved (imaging) pharmacokinetic data over the tumor volume were obtained to visualize the distribution of the redox status within the tumor. The redox images of the tumor in the air‐breathing mice showed significant heterogeneity in the magnitude and spatial distribution of reducing equivalents. On carbogen‐breathing the tissue reduction status decreased considerably, with a concomitant decrease in the heterogeneity of distribution of the redox status. The results suggest that 1) carbogen‐breathing considerably enhances tissue oxygenation and significantly decreases the redox status in RIF‐1 tumor, and 2) changes in the magnitude and distribution of the redox status within the tumor volume during carbogen‐breathing are correlated with the increased tissue oxygenation. Magn Reson Med 48:723–730, 2002. © 2002 Wiley‐Liss, Inc.
Coronary MRA with 3D undersampled projection reconstruction TrueFISP
Authors: Larson Andrew C. , Simonetti Orlando P. , Li Debiao 
Published: October 2002

AbstractUndersampled projection reconstruction (PR) offers improved imaging efficiency allowing a relative tradeoff between signal‐to‐noise ratio (SNR) or streak artifact and the number of acquired k‐space views rather than the tradeoff between resolution or aliasing artifact and the number of acquired k‐space lines inherent to Fourier imaging techniques. TrueFISP (true fast imaging with steady state precession) is ideally suited for undersampled PR imaging because of its inherently high SNR. The purpose of this work was to investigate the feasibility of using undersampled three‐dimensional (3D) PR TrueFISP for breathhold coronary artery imaging. Phantom studies and a preliminary in vivo comparison demonstrated the improved spatial resolution of PR over Fourier TrueFISP with the same imaging time. In a 24‐heartbeat coronary imaging scheme, segmented 3D PR TrueFISP provided a 1.0 × 1.0 mm2 isotropic in‐plane voxel size while acquiring between 93 and 153 views per partition. Streak artifacts were present in some images but were not found to impede coronary artery delineation. In conclusion, 3D undersampled PR TrueFISP provides isotropic in‐plane voxel size within a single breathhold and is a promising technique for coronary artery imaging. Magn Reson Med 48:594–601, 2002. © 2002 Wiley‐Liss, Inc.
Navigator‐gated free‐breathing 3D balanced FFE projection renal MRA: Comparison with contrast‐enhanced breath‐hold 3D MRA in a swine model
Authors: Spuentrup Elmar , Buecker Arno , Meyer Julius , Günther Rolf W. , Stuber Matthias 
Published: October 2002

AbstractA cardiac‐triggered, free‐breathing, 3D balanced FFE projection renal MR angiography (MRA) technique with a 2D pencil beam aortic labeling pulse for selective aortic spin tagging was developed. For respiratory motion artifact suppression during free breathing, a prospective real‐time navigator was implemented for renal MRA. Images obtained with the new approach were compared with standard contrast‐enhanced (CE) 3D breath‐hold MRA in seven swine. Signal properties and vessel visualization were analyzed. With the presented technique, high‐resolution, high‐contrast renal projection MRA with superior vessel length visualization (including a greater visible number of distal branches of the renal arteries) compared to standard breath‐hold CE‐MRA was obtained. The present results warrant clinical studies in patients with renal artery disease. Magn Reson Med 48:739–743, 2002. © 2002 Wiley‐Liss, Inc.
Spatial assessment of articular cartilage proteoglycans with Gd‐DTPA‐enhanced T1 imaging
Authors: Nieminen Miika T. , Rieppo Jarno , Silvennoinen Johanna , Töyräs Juha , Hakumäki Juhana M. , Hyttinen Mika M. , Helminen Heikki J. , Jurvelin Jukka S. 
Published: October 2002

AbstractIn Gd‐DTPA‐enhanced T1 imaging of articular cartilage, the MRI contrast agent with two negative charges is understood to accumulate in tissue inversely to the negative charge of cartilage glycosaminoglycans (GAGs) of proteoglycans (PGs), and this leads to a decrease in the T1 relaxation time of tissue relative to the charge in tissue. By assuming a constant relaxivity for Gd‐DTPA in cartilage, it has further been hypothesized that the contrast agent concentration in tissue could be estimated from consecutive T1 measurements in the absence or presence of the contrast agent. The spatial sensitivity of the technique was examined at 9.4 T in normal and PG‐depleted bovine patellar cartilage samples. As a reference, spatial PG concentration was assessed with digital densitometry from safranin O‐stained cartilage sections. An excellent linear correlation between spatial optical density (OD) of stained GAGs and T1 with Gd‐DTPA was observed in the control and chondroitinase ABC‐treated cartilage specimens, and the MR parameter accounted for approximately 80% of the variations in GAG concentration within samples. Further, the MR‐resolved Gd‐DTPA concentration proved to be an even better estimate for PGs, with an improved correlation. However, the linear relation between MR parameters and PG concentration did not apply in the deep tissue, where MR measurements overestimated the PG content. While the absolute [Gd‐DTPA] determination may be prone to error due to uncertainty of relaxivity in cartilage, or to other contributing factors such as variations in tissue permeability, the experimental evidence highlights the sensitivity of this technique to reflect spatial changes in cartilage PG concentration in normal and degenerated tissue. Magn Reson Med 48:640–648, 2002. © 2002 Wiley‐Liss, Inc.
MR angiography using steady‐state free precession
Authors: Foo Thomas K.F. , Ho Vincent B. , Marcos Hani B. , Hood Maureen N. , Choyke Peter L. 
Published: October 2002

AbstractContrast‐enhanced MR angiography (CE‐MRA) using steady‐state free precession (SSFP) pulse sequences is described. Using SSFP, vascular structures can be visualized with high signal‐to‐noise ratio (SNR) at a substantial (delay) time after the initial arterial pass of contrast media. The peak blood SSFP signal was diminished by <20% 30 min after the initial administration of 0.2 mmol/kg of Gd‐chelate. The proposed method allows a second opportunity to study arterial or venous structures with high image SNR and high spatial resolution. A mask subtraction scheme using spin echo SSFP‐S(−) acquisition is also described to reduce stationary background signal from the delayed SSFP angiography images. Magn Reson Med 48:699–706, 2002. © 2002 Wiley‐Liss, Inc.
Inflammatory processes in amyotrophic lateral sclerosis
Authors: McGeer P. L. , McGeer E. G. 
Published: October 2002

AbstractNeuroinflammation is a characteristic of pathologically affected tissue in several neurodegenerative disorders. These changes can be observed in the brainstem and spinal cord of amyotrophic lateral sclerosis (ALS) cases and in mouse models of the disease. They include an accumulation of large numbers of activated microglia and astrocytes, as well as small numbers of T cells, mostly adhering to postcapillary venules. Accompanying biochemical alterations include the appearance of numerous molecules characteristic of free‐radical attack, the occurrence of proteins associated with activation of the complement cascade, and a sharp upregulation of the enzyme cyclooxygenase 2 (COX‐2). Anti‐inflammatory agents may have a role to play in treating ALS. COX‐2 is a particularly attractive target because of its marked increase in ALS spinal cord. © 2002 Wiley Periodicals, Inc. Muscle Nerve 26: 459–470, 2002
Isolated sarcoid myopathy
Authors: Berger Christian , Sommer Clemens , Meinck Hans‐M. 
Published: October 2002

AbstractA 75‐year‐old housewife presented with a 5‐year history of slowly progressive, painless limb weakness with wasting particularly of the pretibial muscles and without sensory involvement. She was otherwise healthy, but had a history of mild pulmonary sarcoidosis 20 years earlier. Abnormal laboratory findings included serum calcium (3.2 mmol/L; normal 2.15–2.6 mmol/L) and serum angiotensin‐converting enzyme (ACE; 38.2 U/L; normal <22.5 U/L). All other laboratory investigations, including antibody studies and diagnostic work‐up for systemic sarcoidosis, were negative. Muscle biopsy revealed noncaseating epitheloid granulomas, multinuclear giant cells, and lymphoplasmacellular infiltration. The patient was started on methylprednisolone and recovered to some extent. These findings represent a rare case of isolated sarcoid myopathy without concurrent systemic sarcoidosis. © 2002 Wiley Periodicals, Inc. Muscle Nerve 26: 553–556, 2002
Omental graft improves functional recovery of transected peripheral nerve
Authors: Castañeda Francisco , Kinne Rolf K.H. 
Published: October 2002

AbstractThe omentum has several properties that are advantageous for neuronal sprouting and direction. We have therefore analyzed functional recovery following transection of rat sciatic nerve using omental graft to bridge the nerve defect. In group 1, a 25–30‐mm nerve defect was produced and bridged with omental graft, whereas in group 2, an end‐to‐end repair was performed. The sciatic function index (SFI) was assessed at 2‐week intervals until 8 weeks after surgery. Functional recovery was faster in group 1 than in group 2. After 8 weeks, SFI was improved significantly from −100% to −45% (± −4%) in group 1 (P < 0.001) compared to −72% ± −2% in group 2 (n = 10). Histologically, the omental graft contained more newly developed nerve fibers and less scar tissue than the end‐to‐end repair. Thus, omental graft appears to improve directional growth of regenerating axon sprouts and may be a means of treating peripheral nerve injury. © 2002 Wiley Periodicals, Inc. Muscle Nerve 26: 527–532, 2002
Micromechanical modelling of monotonic drained and undrained shear behaviour of granular media using three‐dimensional DEM
Authors: Sitharam Thallak. G. , Dinesh S. V. , Shimizu N. 
Published: October 2002

AbstractIn this paper, numerical simulation results of isotropic compression and triaxial static shear tests under drained and undrained stress paths on polydisperse assembly of loose and dense spheres are presented. An examination of the micromechanical behaviour of loose and dense assemblies under drained and undrained conditions, considering the particulate nature of granular materials, has been carried out to explain micromechanically the granular material behaviour at the grain scale level. The numerical simulations have been carried out using a discrete element model (DEM) which considers a 1000 sphere particle polydisperse assembly with periodic space representing an infinite three‐dimensional space. In this paper, we present how DEM simulations can contribute to developments in constitutive modelling of granular materials through micromechanical approach using information on microstructure evolution. A series of numerical tests are performed using DEM on 3‐D assemblages of spheres to study the evolution of the internal variables such as average co‐ordination number and induced anisotropy during deformation along with the macroscopic behaviour of the assemblage in drained and undrained shear tests. In a qualitative sense, the macroscopic stress–strain results and stress path evolution in these simulations using 3‐D assemblies demonstrate that DEM simulations are capable of reproducing realistic compression and shear behaviour of granular materials. Copyright © 2002 John Wiley & Sons, Ltd.
Spectral profiles of cultured neuronal and glial cells derived from HRMAS 1H NMR spectroscopy
Authors: Griffin Julian L. , Bollard Mary , Nicholson Jeremy K. , Bhakoo Kishore 
Published: October 2002

AbstractIn the investigations of brain function and pathology in vivo by magnetic resonance spectroscopy (MRS), a decrease in the relative concentration of N‐acetyl aspartate (NAA) has been correlated with neuronal cell damage or loss, while a relative increase in the resonance intensity of creatine has been correlated with gliosis. However, neither metabolite is confined strictly to one cell‐type. In this study, pattern recognition of spectra derived from high‐resolution magic angle spinning (HRMAS) 1H NMR spectroscopy was used to distinguish three neural cell types; cortical astrocytes, cerebellar neurones and O‐2A progenitors. The intact cells contained significant amounts of lipid resonances (–CH2CH3 and –CH2CH2CH2–) in all three cell‐types, even when a T2‐edited Carr–Purcell–Meiboom–Gill (CPMG) pulse sequence was used, selectively attenuating resonances from macromolecules. Creatine was also detected in all three cell types. Principle component analysis (PCA) readily differentiated the NMR spectra, based on the individual metabolic profile derived from the cohort of cell type examined using conventional solvent‐suppressed and CPMG pulse sequences. Creatine was not found to contribute to this separation. Moreover, the large lipid content of neuronal cells contributed most to the separation from the other cell types. This suggests that during MRS in vivo, where lipid resonances are commonly ‘edited out’ by T2 delays, significant information may be sacrificed concerning relative contribution from individual cell types. Copyright © 2002 John Wiley & Sons, Ltd.
Follow‐up by one‐ and two‐dimensional NMR of plasma from pigs with ischemia‐induced acute liver failure treated with a bioartificial liver
Authors: Tréhout David , Desille Mireille , Doan Bich‐Thuy , Mahler Stephan , Frémond Benjamin , Mallédant Yannick , Campion Jean‐Pierre , Desbois Jeanne , Beloeil Jean‐Claude , de Certaines Jacques , Clément Bruno 
Published: October 2002

AbstractHepatic encephalopathy may occur following acute hepatic failure (AHF), which results in the release of toxic compounds from the injured liver. These compounds, which induce cerebral edema, are not well characterized, yet. The aim of this study was to evaluate the potential interest of NMR spectroscopy in the follow‐up of different plasma compounds in pigs with ischemia‐induced fulminant hepatic failure treated or not with a bioartificial liver (BAL), which has been previously shown to improve the neurological status of the animals. Qualitative analysis of pig plasma was achieved by one‐dimensional‐1H CPMG, two‐dimensional homonuclear 1H‐1H TOCSY CPMG and heteronuclear 1H‐13C HSQC sequences. Semi‐quantitative analysis of selected plasma metabolites along the disease evolution was carried out on pigs with ischemia‐induced AHF treated with the BAL containing alginate beads with or without hepatocytes. A quantitative longitudinal follow‐up was performed on characteristic metabolites via a one‐dimensional CPMG sequence, including choline, glutamine, N‐acetyl‐glucosamine (NAG), pyruvate and trimethylamine‐N‐oxide (TMAO). The concentrations of choline and TMAO increased from the beginning to the end in animals treated with the BAL containing alginate beads without hepatocytes. Treatment of pigs with BAL containing hepatocytes resulted in an improvement of survival, the plasma concentrations of choline and TMAO being decreased in three out of five animals. Thus, NMR spectroscopy is a useful approach for the identification of toxic compounds which are involved in hepatic encephalopathy associated with AHF. These compounds can be cleared by a BAL resulting in the improvement of survival and neurological parameters of the animals. Copyright © 2002 John Wiley & Sons, Ltd.
Increasing the connectivity of the star graphs
Authors: Cheng Eddie , Lipman Marc J. 
Published: October 2002

AbstractThe star graph Sn proposed by Akers et al. has many advantages over the n‐cube. We show that when a large number of vertices are deleted from Sn the resulting graph can have at most two components, one of which is small. We use this result to solve a successive augmentation problem for Sn. This, in turn, provides extra choices for the topology of large interconnection networks. © 2002 Wiley Periodicals, Inc.
Solving partial constraint satisfaction problems with tree decomposition
Authors: Koster Arie M. C. A. , van Hoesel Stan P. M. , Kolen Antoon W. J. 
Published: October 2002

AbstractIn this paper, we describe a computational study to solve hard partial constraint satisfaction problems (PCSPs) to optimality. The PCSP is a general class of problems that contains a diversity of problems, such as generalized subgraph problems, MAX‐SAT, Boolean quadratic programs, and assignment problems like coloring and frequency planning. We present a dynamic programming algorithm that solves PCSPs based on the structure (tree decomposition) of the underlying constraint graph. With the use of dominance and bounding techniques, we are able to solve small and medium‐size instances of the problem to optimality and to obtain good lower bounds for large‐size instances within reasonable time and memory limits. © 2002 Wiley Periodicals, Inc.
Strategies for computing goal‐oriented a posteriori error measures in non‐linear elasticity
Authors: Larsson Fredrik , Hansbo Peter , Runesson Kenneth 
Published: October 2002

AbstractWe investigate the characteristics and performance of goal‐oriented a posteriori error measures for a class of non‐linear elasticity models, while restriction is made to small strain theory. The chosen error measure of the displacement field can be global or local (probing the chosen quantity in a specific spatial point). The error is computable with the aid of the solution of a dual problem whose data depend on the error measure. The main thrust of the paper is to evaluate the performance of a few different approximation strategies for computing the dual solution. The chosen strategies are compared in terms of accuracy, ease of implementation, reliability and cost‐efficiency. A well‐known numerical example, the Cook's membrane, is used for the numerical evaluations. Copyright © 2002 John Wiley & Sons, Ltd.
Discrete singular convolution and its application to the analysis of plates with internal supports. Part 1: Theory and algorithm
Authors: Wei G. W. , Zhao Y. B. , Xiang Y. 
Published: October 2002

AbstractThis paper presents a novel computational approach, the discrete singular convolution (DSC) algorithm, for analysing plate structures. The basic philosophy behind the DSC algorithm for the approximation of functions and their derivatives is studied. Approximations to the delta distribution are constructed as either bandlimited reproducing kernels or approximate reproducing kernels. Unified features of the DSC algorithm for solving differential equations are explored. It is demonstrated that different methods of implementation for the present algorithm, such as global, local, Galerkin, collocation, and finite difference, can be deduced from a single starting point. The use of the algorithm for the vibration analysis of plates with internal supports is discussed. Detailed formulation is given to the treatment of different plate boundary conditions, including simply supported, elastically supported and clamped edges. This work paves the way for applying the DSC approach in the following paper to plates with complex support conditions, which have not been fully addressed in the literature yet. Copyright © 2002 John Wiley & Sons, Ltd.
On the differentiation of the Rodrigues formula and its significance for the vector‐like parameterization of Reissner–Simo beam theory
Authors: Ritto‐Corrêa M. , Camotim D. 
Published: October 2002

AbstractIn this paper we present a systematic way of differentiating, up to the second directional derivative, (i) the Rodrigues formula and (ii) the spin‐rotation vector variation relationship. To achieve this goal, several trigonometric functions are grouped into a family of scalar quantities, which can be expressed in terms of a single power series. These results are then applied to the vector‐like parameterization of Reissner–Simo beam theory, enabling a straightforward derivation and leading to a clearer formulation. In particular, and in contrast with previous formulations, a relatively compact and obviously symmetric form of the tangent operator is obtained. The paper also discusses several relevant issues concerning a beam finite element implementation and concludes with the presentation of a few selected illustrative examples. Copyright © 2002 John Wiley & Sons, Ltd.
Skeletal remains of dogs unearthed from the Van‐Yoncatepe necropolises
Authors: Onar Vedat , Armutak Altan , Belli Oktay , Konyar Erkan 
Published: October 2002

AbstractA total of 15 dog skulls and a number of bones have been discovered in two burial chambers dating from 1,000 BC in the necropolises of the Van‐Yoncatepe Castle in eastern Turkey. The finds were a dog skeleton in burial chamber M5 and 14 dog skulls and plenty of bones in burial chamber M6. It was determined on examination that the skeleton found in burial chamber M5 was an 11–12‐year female dog, and that the skulls unearthed from burial chamber M6 belonged to dogs with an age range of seven to eight months to 12–13 years. In the latter chamber, however, except for one skull whose sex could not be determined, one was ascertained to belong to a female dog and the rest to males. Calculations of 20 different indices and ratios were made on the skulls. This showed that these skulls were of the dolichocephalic type. It was observed that there were signs of a widespread periodontal disease and alveolar recession. Enamel hypoplasia and abscess chambers detected on the teeth, and deformations observed in the hard palate were evidence enough to suggest that these were undernourished dogs. There were also some facial fractures, which were noticed to have occurred before death. On the other hand, examination carried out on the bones revealed that the dogs were of medium size, and that they were likely to have had a withers height of 50–55 cm. The data obtained from both the burial chambers brought to light the fact that these dogs were more of the hunting or working types. Copyright © 2002 John Wiley & Sons, Ltd.