bluuebunny/crossref_metadata_2025_split huggingface dataset:
Imaging spin probe distribution in the tumor of a living mouse with 250 MHz EPR: Correlation with BOLD MRI
Authors: Williams Benjamin B. , al Hallaq Hania , Chandramouli G.V.R. , Barth Eugene D. , Rivers Jonathan N. , Lewis Marta , Galtsev Valeri E. , Karczmar Gregory S. , Halpern Howard J. 
Published: August 2002

AbstractElectron paramagnetic resonance imaging (EPRI) promises to provide new insights into the physiology of tissues in health and disease. Understanding the in vivo imaging capability of this new modality requires comparison with other physiologically responsive techniques. Here, an initial comparison between 2D EPR spatial imaging of a narrow single line injectable paramagnetic trityl spin probe and 2D slice‐selected carbogen subtraction BOLD MRI is presented. The images were obtained from the same FSa fibrosarcoma grown in the leg of a C3H mouse. This tumor was unusual in comparison with others imaged with subtraction BOLD MRI because of its peripheral distribution of intensity. The spatial distribution of the EPR spin probe showed the same peripheral distribution. The pixel resolutions of these images are comparable. These images provide an early in vivo comparison of EPRI with a well‐established imaging modality. The comparison validates the in vivo distribution of spin probe as imaged with EPRI, and provides a proof of principle for the comparison of BOLD and EPRI. Magn Reson Med 47:634–638, 2002. © 2002 Wiley‐Liss, Inc.
In vivo mapping of the fast and slow diffusion tensors in human brain
Authors: Clark Chris A. , Hedehus Maj , Moseley Michael E. 
Published: August 2002

AbstractRecent studies have shown that the diffusional signal decay in human brain is non‐monoexponential and may be described in terms of compartmentalized water fractions. Diffusion tensor imaging (DTI), which provides information about tissue structure and orientation, typically uses b values up to 1000 s mm−2 so that the signal is dominated by the fast diffusing fraction. In this study b factors up to 3500 s mm−2 are utilized, allowing the diffusion tensor properties of the more slowly diffusing fraction to be mapped for the first time. The mean diffusivity (MD) of the slow diffusion tensor was found to exhibit strong white/gray matter (WM/GM) contrast. Maps depicting the principal direction of the slow tensor indicated alignment with the fast tensor and the known orientation of the WM pathways. Magn Reson Med 47:623–628, 2002. © 2002 Wiley‐Liss, Inc.
Near infrared muscle spectroscopy in patients with Friedreich's ataxia
Authors: Lynch David R. , Lech Gwen , Farmer Jennifer M. , Balcer Laura J. , Bank William , Chance Britton , Wilson Robert B. 
Published: August 2002

AbstractFriedreich's ataxia is a progressive neurodegenerative disorder of the afferent cerebellar pathways associated with mitochondrial dysfunction at the cellular level. We have used noninvasive continuous near infrared muscle spectroscopy (NIRS) to investigate the delivery and utilization of oxygen in response to exercise in this disorder. Patients performed an incremental treadmill walking protocol in which levels of muscle deoxygenation or oxygenation were continuously measured in the medial calf muscle. The kinetics of recovery from exercise‐induced deoxygenation, called the half‐time of recovery (t1/2) were determined. The t1/2 was prolonged in patients with Friedreich's ataxia compared with controls, and the degree of prolongation correlated with the length of the shorter GAA repeat, a genetic measure that correlates with the age of onset of disease. The t1/2 also correlated inversely with patient age and with the maximum treadmill speed attained. Several patients also displayed features consistent with inadequate oxygen utilization by muscle. These results suggest that NIRS may be an effective tool for monitoring the biochemical and functional features of Friedreich's ataxia in parallel. © 2002 Wiley Periodicals, Inc. Muscle Nerve 25: 000–000, 2002
Role of adaptive plasticity in recovery of function after damage to motor cortex
Authors: Nudo Randolph J. , Plautz Erik J. , Frost Shawn B. 
Published: August 2002

AbstractBased upon neurophysiologic, neuroanatomic, and neuroimaging studies conducted over the past two decades, the cerebral cortex can now be viewed as functionally and structurally dynamic. More specifically, the functional topography of the motor cortex (commonly called the motor homunculus or motor map), can be modified by a variety of experimental manipulations, including peripheral or central injury, electrical stimulation, pharmacologic treatment, and behavioral experience. The specific types of behavioral experiences that induce long‐term plasticity in motor maps appear to be limited to those that entail the development of new motor skills. Moreover, recent evidence demonstrates that functional alterations in motor cortex organization are accompanied by changes in dendritic and synaptic structure, as well as alterations in the regulation of cortical neurotransmitter systems. These findings have strong clinical relevance as it has recently been shown that after injury to the motor cortex, as might occur in stroke, post‐injury behavioral experience may play an adaptive role in modifying the functional organization of the remaining, intact cortical tissue. © 2001 John Wiley & Sons, Inc. Muscle Nerve 24: 1000–1019, 2001
A constitutive model for the dynamic and high‐pressure behaviour of a propellant‐like material: Part I: Experimental background and general structure of the model
Authors: Trumel Hervé , Dragon André , Fanget Alain , Lambert Philippe 
Published: August 2002

AbstractThis paper is the first part of a work that aims at developing a mechanical model for the behaviour of propellant‐like materials under high confining pressure and strain rate. The behaviour of a typical material is investigated experimentally. Several microstructural deformation processes are identified and correlated with loading conditions. The resulting behaviour is complex, non‐linear, and characterized by multiple couplings. The general structure of a relevant model is sought using a thermodynamic framework. A viscoelastic‐viscoplastic‐compaction model structure is derived under suitable simplifying assumptions, in the framework of finite, though moderate, strains. Model development, identification and numerical applications are given in the companion paper. Copyright © 2001 John Wiley & Sons, Ltd.
Delayed plastic model for time‐dependent behaviour of materials
Authors: Namikawa Tsutomu 
Published: August 2002

AbstractA delayed plastic model, based on the theory of plasticity, is proposed to represent the time‐dependent behaviour of materials. It is assumed in this model that the stress can lie outside the yield surface and the conjugate stress called static stress is defined on the yield surface. The stress–strain relation is calculated based on the plastic theory embedding the static stress. Thus, the stress–strain relation of the model practically corresponds to that of the inviscid elastoplastic model under fairly low rate deformation. The delayed plastic model is coupled with the Cam‐clay model for normally consolidated clays. The performance of the model is then examined by comparing the model predictions with reported time‐dependent behaviour of clays under undrained triaxial conditions. It is shown that the model is capable of predicting the effect of strain rate during undrained shear and the undrained creep behaviour including creep rupture. Copyright © 2001 John Wiley & Sons, Ltd.
Frictional contact of laminated elastic half‐spaces allowing interface cavities. Part 1: Analytical treatment
Authors: Kryshtafovych A. A. , Matysiak S. J. 
Published: August 2002

AbstractThe paper deals with the plane problem on frictional contact of stratified elastic half‐spaces provided discontinuity of their direct touch. Imperfectness of contact of the bodies is assumed to be caused by surface unevenness of their surface layers. The problem is formulated within the framework of the homogenized model with microlocal parameters. Using the method of complex potentials in combination with the method of interface gaps the problem is reduced to a singular integral equation on the function of interface gap height. Copyright © 2001 John Wiley & Sons, Ltd.
Alkaline pH changes in the cerebellum of asymptomatic HIV‐infected individuals
Authors: Patton Holly K. , Chu Wen‐Jang , Hetherington Hoby P. , Hollander Jan den , Stewart Katharine E. , Raper James L. , Shelton Brent J. , Benveniste Etty N. , Benos Dale J. 
Published: August 2002

AbstractHuman immunodeficiency virus (HIV) infection of the brain causes a complex cascade of cellular events involving several different cell types that eventually leads to neuronal cell death and the manifestation of the AIDS‐associated dementia complex (ADC). Upon autopsy HIV‐infected individuals show lesions within subcortical regions of the brain, including the cerebellum. Previously we have demonstrated, in primary and cell culture models of rat and human astrocytes, a change in intracellular pH (pHi) due to increased Na+/H+ exchange following exposure to inactivated virus or gp120, the major HIV envelope glycoprotein. To further investigate whether any such in vivo pHi changes occur in human brains subsequent to HIV infection, we measured the pHi of the cerebellum in eight HIV‐positive individuals and nine healthy volunteers using 31P magnetic resonance spectroscopy imaging (MRSI) at high field strength (4.1 T). The results showed a significant difference between the age‐adjusted mean pHi in the cerebellum in control group and patient groups (7.11 ± 0.03 vs 7.16 ± 0.04), and further HIV‐infected individuals displayed a significant increase in the number of cerebellar volume elements that were alkaline. We hypothesize that this propensity towards alterations in cerebellar pHi may portend later neurological involvement resulting from HIV infection. Copyright © 2001 John Wiley & Sons, Ltd.
Abbreviations used:

ADC

AIDS dementia complex

AIDS

auto‐immune deficiency syndrome

ATP

adenosine triphosphate

CNS

central nervous system

PCr

phosphocreatine

PDE

phosphodiester

Pi

inorganic phosphate

PME

phosphomonoester

ROI

region of interest

SID

spectroscopic imaging display

SNR

signal‐to‐noise ratio

TE

echo time

TIR

inversion recovery time

TR

repetition time.
A two‐phase combined QoS‐based handoff scheme in a wireless ATM network
Authors: Hać Anna , Peng Jing 
Published: August 2002

AbstractWe describe the QoS‐based rerouting algorithm that is designed to implement a two‐phase inter‐switch handoff scheme for wireless ATM networks. We propose to use path extension for each inter‐switch handoff, and invoke path optimization when the handoff path exceeds the delay constraint or maximum path extension hops constraint. We study three types of path optimization schemes: combined QoS‐based, delay‐based and hop based path rerouting schemes. Copyright © 2001 John Wiley & Sons, Ltd.
A framework for the transmission of streaming media to mobile devices
Authors: Curran Kevin , Parr Gerard 
Published: August 2002

AbstractOne interesting problem is the delay imposed upon mobile receivers when switching between wireless cells. We provide a solution to this in the form of an extension of Mobile IP's handoff algorithm. Our solution involves the exploitation of mobility prediction to predict a mobile terminal's future location based on its previous history (i.e. the last cell that it has been in) and for the media stream to be already present and cached by next cells base station ready for receiving by the mobile device. Copyright © 2002 John Wiley & Sons, Ltd.
Stability of networks and protocols in the adversarial queueing model for packet routing
Authors: Goel Ashish 
Published: August 2002

AbstractThe adversarial queueing theory model for packet routing was suggested by Borodin et al. We give a complete and simple characterization of all networks that are universally stable in this model. We show that the same characterization also holds for networks which are stable given that the packet forwarding protocol is FIFO (First in First out). We also show that a specific greedy protocol, SIS (Shortest in System), is stable against 0/1 stochastic adversaries. © 2001 John Wiley & Sons, Inc.
On the construction of combinedk‐fault‐tolerant Hamiltonian graphs
Authors: Hung Chun‐Nan , Hsu Lih‐Hsing , Sung Ting‐Yi 
Published: August 2002

AbstractA graphGis a combinedk‐fault‐tolerant Hamiltonian graph (also called a combinedk‐Hamiltonian graph) ifG−Fis Hamiltonian for every subsetF⊂ (V(G) ∪E(G)) with |F| =k. A combinedk‐Hamiltonian graphGwith |V(G)| =nis optimal if it has the minimum number of edges among alln‐nodek‐Hamiltonian graphs. Using the concept of node expansion, we present a powerful construction scheme to construct a larger combinedk‐Hamiltonian graph from a given smaller graph. Many previous graphs can be constructed by the concept of node expansion. We also show that our construction maintains the optimality property in most cases. The classes of optimal combinedk‐Hamiltonian graphs that we constructed are shown to have a very good diameter. In particular, those optimal combined 1‐Hamiltonian graphs that we constructed have a much smaller diameter than that of those constructed previously by Mukhopadhyaya and Sinha, Harary and Hayes, and Wang et al. © 2001 John Wiley & Sons, Inc.
Pharmacological evidence for GABAergic regulation of specific behaviors inDrosophila melanogaster
Authors: Leal Sandra M. , Neckameyer Wendi S. 
Published: August 2002

AbstractWe have identified several GABAergic‐modulated behaviors inDrosophila melanogasterby employing a pharmacological approach to disrupt GABA transporter functionin vivo. Systemic treatment of adult female flies with the GABA transport inhibitorsDL‐2,4‐diaminobutyric acid (DABA) or R,S‐nipecotic acid (NipA), resulted in diminished locomotor activity, deficits in geotaxis, and the induction of convulsive behaviors with a secondary loss of the righting reflex. Pharmacological evidence suggested that the observed behavioral phenotypes were specific to disruption of GABA transporter function and GABAergic activity. The effects of GABA reuptake inhibitors on locomotor activity were dose dependent, pharmacologically distinct, and paralleled their known effects in mammalian systems. Recovery of normal locomotor activity and the righting reflex in DABA‐ and NipA‐treated flies was achieved by coadministration of bicuculline (BIC), a GABA receptor antagonist that supresses GABAergic activity in mammals. Recovery of these behaviors was also achieved by coadministration of gabapentin, an anticonvulsant agent that interacts with mammalian GABAergic systems. Finally, behavioral effects were selective because other specific behaviors such as feeding activity and female sexual receptivity were not affected. Related pharmacological analyses performedin vitroon isolatedDrosophilasynaptic plasma membrane vesicles demonstrated high affinity, saturable uptake mechanisms for [3H]‐GABA; further competitive inhibition studies with DABA and NipA demonstrated their ability to inhibit [3H]‐GABA transport. The existence of experimentally accessible GABA transporters inDrosophilathat share conserved pharmacological properties with their mammalian counterparts has resulted in the identification of specific behaviors that are modulated by GABA. © 2002 Wiley Periodicals, Inc. J Neurobiol 50: 245–261, 2002; DOI 10.1002/neu.10030
Decreased calretinin expression in cerebellar granule cells in the leaner mouse
Authors: Nahm Sang‐Soep , Tomlinson Dana J. , Abbott Louise C. 
Published: August 2002

AbstractWe investigated calretinin expression in cerebellar granule cells of 30‐day‐old leaner mice to understand possible changes in calcium homeostasis due to the calcium channel mutation that these mice carry. Quantitative in situ hybridization histochemistry showed decreased calretinin mRNA expression in the leaner cerebellum. Immunohistochemical staining also revealed decreased calretinin immunoreactivity in the leaner cerebellum. To exclude the effect of granule cell loss that occurs in the leaner mouse when comparing cerebellar calretinin expression, the number of granule cells per unit area in the cerebellum was compared to the wild‐type cerebellum. Granule cell counts per unit area of cerebellum revealed similar numbers of granule cells present in wild‐type and leaner mice. Laser capture microdissection (LCM) was employed to obtain an equal number of granule cells from wild‐type and leaner mice. Western blot analysis with LCM‐procured cerebellar granule cells showed decreased calretinin expression in leaner granule cells. These results indicate that there is an absolute decrease in calretinin expression in leaner granule cells even when granule cell loss is taken into account. Decreased calretinin expression in leaner granule cells may contribute to altered calcium buffering capacity. This alteration could be an adaptive change due to the calcium channel dysfunction, and may result in abnormal neuronal excitability and gene expression. © 2002 Wiley Periodicals, Inc. J Neurobiol 51: 313–322, 2002
NMDA receptor regulation of cell death in the rat olfactory bulb
Authors: Fiske Brian K. , Brunjes Peter C. 
Published: August 2002

AbstractCell death is widespread in the developing nervous system and is under complex regulation by numerous intra‐ and intercellular mechanisms. Blockade of the N‐methyl‐D‐aspartate (NMDA) subtype of glutamate receptor has been shown to promote cell death in the developing brain (Ikonomidou et al., 1999), suggesting that afferent functional activation is an important regulator of cell survival. The olfactory bulb, the first central relay for olfactory information from the nose, is well suited for examining the role of afferent activity in neuronal development. Functional deprivation is easily performed by surgical blockade of airflow to one side of the nasal passage, which results in dramatic alterations in postnatal development of the bulb (Brunjes, 1994), including enhanced neuronal loss (Frazier and Brunjes, 1988; Najbauer and Leon, 1995). The present report examined the specific role of NMDA receptor activation in regulating cell survival within the rat bulb. Pharmacological blockade of receptors with the noncompetitive channel blocker MK‐801 (3 × 0.5 mg/kg i.p.) resulted in profound increases in cell death within 24 h. Furthermore, in contrast to other regions, where the effects of receptor blockade were confined to the first 2 postnatal weeks (Ikonomidou et al., 1999), enhancement of cell death was seen in the deeper granule cell‐containing regions of the bulb with injections as late as postnatal day 28. In addition, the effects of MK‐801 were much more dramatic than those seen after unilateral naris closure, suggesting that NMDA receptor activation may mediate additional survival pathways in the bulb beyond that provided by first nerve input. © 2001 John Wiley & Sons, Inc. J Neurobiol 47: 223–232, 2001
Barrier variational generation of quasi‐isometric grids
Authors: Garanzha V. A. 
Published: August 2002

AbstractA grid generation method based on the minimization of the discrete barrier functional with feasible set consisting of quasi‐isometric grids is suggested. The deviation from isometry for given grid connectivity and prescribed boundary conditions is minimized via the contraction of the feasible set into a small vicinity of the optimal grid. Formulation of functional with given metrics in both physical and logical spaces allows to consider the adaptive grid generation in terms of quasi‐isometric grids and cover many practical applications. A fast and reliable grid untangling procedure based on the penalty‐like reformulation of barrier functional and the continuation technique is described. Numerical experiments demonstrate that the suggested functional produces high‐quality grids with small global condition numbers. Copyright © 2001 John Wiley & Sons, Ltd.
An inverse eigenvalue method for frequency isolation in spring–mass systems
Authors: Egaña Juan C. , Kuhl Nelson M. , Santos Luis C. 
Published: August 2002

AbstractThe action of external vibrating forces on mechanical structures can cause severe damages when resonance occurs. The removal of natural frequencies of the structure from resonance bands is therefore of great importance. This problem is called frequency isolation problem and is the subject of this paper. A new inverse eigenvalue method is proposed and applied to spring–mass systems, which have generated much interest in the literature as prototypes of vibrating structures. The novelty of the method lies in using the zeros of the frequency response function at the last mass as control variables in an optimization problem to minimize the impact of redesign. Numerically accurate algorithms for computing the sensitivity with respect to the control variables are presented, which form the basis of an efficient multidimensional search strategy to solve the frequency isolation problem. Copyright © 2001 by John Wiley & Sons, Ltd.
Decoupling preconditioners in the implicit parallel accurate reservoir simulator (IPARS)
Authors: Lacroix Sébastien , Vassilevski Yuri V. , Wheeler Mary F. 
Published: August 2002

AbstractThis paper presents an overview of two‐stage decoupling preconditioning techniques employed in the implicit parallel accurate reservoir simulator (IPARS) computational framework for modelling multi‐component multi‐phase flow in porous media. The underlying discretization method is implicit Euler in time and mixed finite elements or cell‐centred finite differences in space. IPARS permits rigorous, physically representative coupling of different physical and numerical flow models in different parts of the domain and accounts for structural discontinuities; the framework currently includes eight physical models. For simplicity of exposition, we have restricted our discussion to a two‐phase oil–water model and a three‐phase black oil model. Our decoupling approach involves extracting a pressure equation from the fully coupled linearized system thus allowing for a more accurate preconditioning of a discrete elliptic problem of lower dimension. Copyright © 2001 John Wiley & Sons, Ltd.
Kinematically admissible meshless approximation using modified weight function
Authors: Kang Myung‐Seok , Youn Sung‐Kie 
Published: August 2002

AbstractIn meshless methods, in general, the shape functions do not satisfy Kronecker delta properties at nodal points. Therefore, imposing essential boundary conditions is not a trivial task as in FEM. In this regard, there has been a great deal of endeavor to find ways to impose essential boundary conditions. In this study, a new scheme for imposing essential boundary conditions is developed. Weight functions are modified by multiplying with auxiliary weight functions and the resulting shape functions satisfy Kronecker delta properties on the boundary nodes. In addition, the resulting shape functions possess linear interpolation features on the boundary segments where essential boundary conditions are prescribed. Therefore, the essential boundary conditions can be exactly satisfied with the new method. More importantly, the imposition of essential boundary conditions using the present method is infinitely easy as in the finite element method. Numerical examples show that the method also retains high convergence rate comparable to the Lagrange multiplier method. Copyright © 2001 John Wiley & Sons, Ltd.