bluuebunny/crossref_metadata_2025_split huggingface dataset:
Idiopathic bilateral diaphragmatic paralysis
Authors: Valls‐Solé Josep , Solans Margarita 
Published: August 2002

AbstractA 41‐year‐old man complained of subacute onset of dyspnea and pain in the neck and chest. He was diagnosed with bilateral diaphragmatic paralysis, based on clinical inspection of the breathing pattern and transdiaphragmatic pressure recording, and was trained to use a portable bi‐level positive airway pressure apparatus (BiPAP). Needle electromyography showed profuse fibrillation potentials and positive waves in the diaphragm, more abundant on the right than left side, and no response to phrenic nerve stimulation. Other muscles were not involved. Follow‐up examinations, performed at 9 and 12 months after onset of paralysis, demonstrated a slow but progressive improvement of the patient's respiratory function, together with the appearance of reinnervation potentials in the diaphragm, and polyphasic, long‐latency responses to phrenic nerve stimulation. The subacute onset of the paralysis associated with local pain, and its subsequent recovery, suggest bilateral proximal lesions in the phrenic nerves. In the absence of traumatic or metabolic causes, these findings suggest that the phrenic nerve can be a target in idiopathic neuritis. © 2002 Wiley Periodicals, Inc. Muscle Nerve 25: 000–000, 2002.
Gender, body mass and age as risk factors for ulnar mononeuropathy at the elbow
Authors: Richardson James K. , Green Donald F. , Jamieson Sarah C. , Valentin F. Clifford 
Published: August 2002

AbstractFactors that predispose patients to ulnar mononeuropathy at the elbow (UME) are poorly defined. We compared 112 electrodiagnostic reports which met criteria for definite or probable UME to 104 reports which excluded UME. Male gender was strongly associated with definite (OR = 6.9, 95% CI = 2.4–20.4; P < 0.001) and all UME (OR = 2.2, 95% CI = 1.2–4.1; P = 0.010) after controlling for age and body mass index (BMI). Among men, UME was associated with increasing age (P = 0.008) but not a decreased BMI. Women, however, demonstrated an association between decreased BMI and UME (OR = 2.3, 95% CI = 1.3–4.2 for BMI ≤22.0 versus >22.0). These findings, in conjunction with gender differences in ulnar motor nerve parameters among UME subjects and controls, suggest that the pathophysiology of UME differs with gender. © 2001 John Wiley & Sons, Inc. Muscle Nerve 24:551–554, 2001
Sodium influx during action potential in innervated and denervated rat skeletal muscles
Authors: Kotsias Basilio A. , Venosa Roque A. 
Published: August 2002

AbstractResting Na+ influx (JiNa) was measured in innervated and denervated (1–6 days) rat extensor digitorum longus muscle in the absence and presence of 2 μmol/L tetrodotoxin (TTX).The mean value of Na+ permeability (PNa) in innervated muscles was 49.6 ± 2.6 pm.s−1. At the second day postdenervation, it decreased by about 45%. This was followed, between the second and fourth days, by a sharp rise, which by the sixth day reached a steady value ∼2.5 times greater than that of innervated muscles. This, most likely, generated the 30% increase in internal [Na+] concentration ([Na+]I) observed at this time. Tetrodotoxin reduced PNa of both innervated and denervated muscles by about 25%. In 6‐day denervated muscles, virtually all the TTX effect on PNa represents the blockage of TTX‐resistant Na+ channels. Denervation produced a depolarization of about 20 mV by the sixth day. The extra JiNa per action potential (AP) decreased monotonically with time after denervation from 20.0 ± 3.8 in innervated to 11.1 ± 1.0 nmol.g−1.AP−1 in 6‐day denervated muscles. The overshoot of the AP decreased from 15 ± 1 in innervated to 7 ± 1 mV in 6‐day denervated muscles. Likewise, the maximum rate of rise (+dV/dt), an expression of the inward Na+ current, fell from 305 ± 14 in innervated to 188 ± 18 V.s−1 in 6‐day denervated muscles. The estimated 6‐day denervated/innervated ratio of peak Na+ conductance (gNa) was 0.67. The changes in AP parameters promoted by denervation were substantially reduced when both innervated and denervated fibers were hyperpolarized to −90 mV. These results suggest that the depolarization, mainly due to the increase in PNa /PK ratio, increases Na+ inactivation and consequently reduces peak gNa , in spite of the absolute increment in resting TTX‐sensitive PNa. This, in addition to the moderate reduction in the inward driving force on Na+, decreases the inward Na+ current and the extra JiNa per AP. © 2001 John Wiley & Sons, Inc. Muscle Nerve 24: 1026–1033, 2001
Influence of age and height on nerve conduction
Authors: Rivner Michael H. , Swift Thomas R. , Malik Khalid 
Published: August 2002

AbstractPrevious studies demonstrated age‐ and height‐related slowing of nerve conduction velocity (NCV) and reduction in nerve response amplitude. Unfortunately, many studies examined discontinuous populations, preventing regression analysis. The correlation coefficients of available studies vary widely, preventing clear conclusions. We retrospectively examined 3969 clinically normal subjects ranging in age from 20 to 95 years from a total of 22,420 electrodiagnostic studies done between 1986 and 1998. The correlation of NCV with height was stronger than with age. Regression equations using both factors account for 12–27% of the variance. Responses were seen in the majority of patients aged 70 years and older, but the percentage of normals who had no response increased with advancing age. Age was strongly inversely correlated with the amplitudes of both sensory and motor responses, accounting for 7–16% of the variance. Regression equations using both height and age improved this correlation, accounting for 7–22% of the variance. Therefore, both height and age must be taken into consideration when normal values are developed. © 2001 John Wiley & Sons, Inc. Muscle Nerve 24: 1134–1141, 2001
Nerve lesions and the generation of pain
Authors: Campbell James N. 
Published: August 2002

AbstractThis review addresses the issue of how axotomy of peripheral nerve fibers leads to pain and hyperalgesia. The point of axotomy (the nerve injury site), the dorsal root ganglia, and the dorsal horn of the spinal cord are candidate sites for generation of the pain signal that is likely to be critical for maintaining the neuropathic pain state. This review considers neuropathic pain from a “systems” perspective, tracing concepts of neuropathic pain from the work of Henry Head to the present. Surprisingly, the nerve injury site and the dorsal root ganglion belonging to a transected spinal nerve do not give rise to spontaneous activity in putative C‐fiber nociceptors. The intact nociceptor belonging to adjacent uninjured spinal nerves, however, does acquire abnormal spontaneous activity and a chemical sensitivity to catechols. It is suggested that partially denervated tissues in the nerve, skin, and other locations may release substances that, in turn, sensitize the intact nociceptors. These abnormalities in the intact nociceptor, which arise in the context of Wallerian degeneration, probably play a role in creating or maintaining the abnormal pain state. These considerations probably also apply to the understanding of pain arising in other neuropathies. The findings relative to the “intact” nociceptor provide a rationale by which to understand how therapies distal to the nerve injury site may diminish pain. © 2001 John Wiley & Sons, Inc. Muscle Nerve 24: 1261–1273, 2001.
Multiphase model for inclusion‐reinforced geostructures: Application to rock‐bolted tunnels and piled raft foundations
Authors: Sudret Bruno , de Buhan Patrick 
Published: August 2002

AbstractA multiphase model is proposed to describe the mechanical behaviour of geomaterials reinforced by linear inclusions. This macroscopic approach considers the reinforced soil or rock mass as the superposition of continuous media. Equations of motion and constitutive laws of the model are first derived. Its implementation in a finite element computer code is then detailed. A modified implicit algorithm for elastoplastic problems is proposed. The model and its implementation are fully validated for rock‐bolted tunnels (comparison with scale model experiments) and piled raft foundations (comparison with the classical ‘hybrid method’). The Messeturm case history is finally presented to assess the handiness of the approach for real structures. Copyright © 2001 John Wiley & Sons, Ltd.
A phenomenological constitutive model for rocks with shear failure mode
Authors: Zhou G. L. , Tham L. G. , Lee P. K. K. , Tsui Y. 
Published: August 2002

AbstractIn this paper, a phenomenological constitutive model is proposed to simulate the stress–strain behaviours of intact rocks with shear failure mode. The model captures a wide range of behaviours of rock material such as elastic, plastic, strain softening, ‘Class II’, strain localization, elastic modulus degradation, etc. The sensitivity of the stress–strain relation on the parameters is also investigated. Typical results obtained by testing a number of granite and marble specimens are used to validate the proposed model. Copyright © 2001 John Wiley & Sons, Ltd.
Volumetric sand production model and experiment
Authors: Papamichos E. , Vardoulakis I. , Tronvoll J. , Skjærstein A. 
Published: August 2002

AbstractA sand production model was developed for volumetric sand production predictions that take into account the effects of the external stresses and fluid flow rate. The model couples the poro‐mechanical behaviour of the solid–fluid system with the erosion behaviour of the solids due to fluid flow. It predicts reasonably experimental volumetric sand production data from a hollow cylinder test on a weak sandstone. The test results show that in weak and compactive sandstones, sand production is associated with decohesioning and plasticification of a zone around the inner hole which can then be mobilized by the hydrodynamic forces of the fluid flow. The sand production rate increases both with external applied stress and fluid flow rate but it is constant with time under constant external stress and fluid flow rate. In both cases a critical lower limit has to be exceeded for sand production initiation. Copyright © 2001 John Wiley & Sons, Ltd.
Analytical simulation of the dynamic compressive strength of a granite using the sliding crack model
Authors: Li H. B. , Zhao J. , Li T. J. , Yuan J. X. 
Published: August 2002

AbstractA sliding crack model is employed to simulate rock strength under dynamic compression. It is assumed that the growth and nucleation of a sliding crack array presented results in the shear fault failure and dominate the mechanical properties of rock material. The pseudo‐tractions method is used to calculate the stress intensity factor of the sliding crack array under compression. With the utilization of a dynamic crack growth criterion, the growth of the sliding crack array is studied and the simulated strengths of a granite under dynamic compression are correspondingly obtained. It is concluded that the simulated rock strengths increase with increasing strain rates at different confining pressures, and the rising rates have a trend to decrease with increasing confining pressures. It is also indicated that the simulated rock strengths increase with increment of confining pressure at different strain rates, and the rising rates are almost identical at different strain rates. The simulation results are validated by the experimental data for the granite. Copyright © 2001 John Wiley & Sons, Ltd.
A constitutive model for crushed salt
Authors: Olivella S. , Gens A. 
Published: August 2002

AbstractA constitutive model for crushed salt is presented in this paper. A creep constitutive model is developed first and compared with test results. The constitutive model presented here concentrates on creep deformation because saline media behave basically in a ductile and time‐dependent way. An idealized geometry is used as a common framework to obtain stress–strain macroscopic laws based on two deformation mechanisms: fluid‐assisted diffusional transfer creep and dislocation creep. The model is able to predict strain rates that compare well with results from laboratory tests under isotropic and oedometric conditions. Macroscopic laws are written using a non‐linear viscous approach, which incorporates also a viscoplastic component, based on critical state theory. The viscoplastic term is intended for non‐creep deformation mechanisms such as grain reorganization and crushing. Copyright © 2002 John Wiley & Sons, Ltd.
Bulbocavernosus muscle responses after suprapubic stimulation: Analysis and measurement of suprapubic bulbocavernosus reflex latency
Authors: Amarenco Gerard , Bayle Beatrice , Ismael Samer Sheikh , Kerdraon Jacques 
Published: August 2002

AbstractOur objective was to describe pelvic floor responses with measurement of reflex latency after suprapubic mechanical stimulation. Twenty‐one patients without neurological disease were studied. They were 14 women and seven men. The mean age was 51 (SD = 14.2). Motor responses were recorded with a needle electrode inserted in the left bulbocavernosus muscle. Stimulation was delivered with an electromechanical hammer, tapping directly on the suprapubic area. A polyphasic muscular response was always easily elicited in all patients. The man latency was 67.5 milliseconds (SD = 14.7). The reproducibility between the first and second mechanical responses was good with no statistical difference (r=0.966;P = 0.0001). In three patients who underwent cystometry, no rise in detrusor pressure was observed during mechanical stimulation of the suprapubic area. Our study clearly demonstrates a suprapubic bulbocavernosus reflex (SBR). Tapping the suprapubic area is a strong stimulus, reflexively mediated, used in the management of neurogenic bladder to determine a bladder contraction. However, the reflex consisting of pelvic floor muscle contraction after suprapubic stimulation was not specifically studied in humans. Many arguments can be put forth for a polysynaptic reflex (polyphasic response, habituation and short latency of the reflex, mean latency in the habitual values of R2 responses after electrical stimulation of the dorsal nerve of the penis). We hypothesize that the true stimulus is the stimulation of the bladder wall tensoreceptors, the integration level of the SBR is the sacral segments and the efferent limb the pudendal nerve, and afferent pathways could be conducted by pelvic nerve fibers. Competition between a preponderant (or exaggerated) SBR and a bladder contraction after suprapubic tapping may constitute an equivalent of detrusor‐sphincter dyssynergia in some suprasacral bladders. Neurourol. Urodynam. 21:210–213, 2002. © 2002 Wiley‐Liss, Inc.
1H NMR spectroscopy as a tool to evaluate key metabolic functions of primary porcine hepatocytes after cryopreservation
Authors: Dabos Konstantinos J. , Parkinson John A. , Hewage Chandralal , Nelson Leonard J. , Sadler Ian H. , Hayes Peter C. , Plevris John N. 
Published: August 2002

AbstractProton NMR spectroscopy of biological fluids has produced interesting results lately. We used the technique to investigate the effects of cryopreservation on primary porcine hepatocytes as successful cryopreservation of primary porcine hepatocytes is of importance to the development of bioartificial liver support systems. After isolation 108 hepatocytes were cryopreserved for 1 week in Williams E/10% DMSO, either by quick freezing (−5 to −30 °C/min), slow freezing (−0.3 to −3 °C/min) or stepwise freezing protocols on cell suspensions and confluent cell plates. Plating efficiency was assessed by percentage LDH release. Metabolic functions of cryopreserved hepatocytes at 24 h post‐thawing were compared with those of fresh hepatocyte cultures at 48 h. 1H nuclear magnetic resonance spectroscopy of the culture medium post‐incubation, using the presaturation technique, assessed the following: glucose metabolism, transamination and glutamine synthesis and succinate synthesis. Freshly isolated cells had a viability of 82 ± 4.3% and a plating efficiency of 87 ± 3.8%. All cryopreservation protocols resulted in significantly reduced viability and plating efficiency. No significant differences were observed between different cryopreservation media or protocols. When comparing cryopreserved with freshly isolated cells, we observed that metabolism of acetyl‐CoA precursors was significantly impaired in cryopreserved cells. Lactate and pyruvate production was also significantly less, although glucose consumption was similar. No differences were observed in gluconeogenic amino acid metabolism, transamination and urea synthesis. 1H NMR spectroscopy can be used to provide information about metabolic activity and functions of cultured primary cells. Copyright © 2002 John Wiley & Sons, Ltd.
Approximate inverse computation using Frobenius inner product
Authors: Montero G. , González L. , Flórez E. , García M. D. , Suárez A. 
Published: August 2002

AbstractParallel preconditioners are presented for the solution of general linear systems of equations. The computation of these preconditioners is achieved by orthogonal projections related to the Frobenius inner product. So, minM∈𝒮∥AM−I∥ F and matrix M0∈𝒮 corresponding to this minimum (𝒮 being any vectorial subspace of ℳ︁n(ℝ)) are explicitly computed using accumulative formulae in order to reduce computational cost when subspace 𝒮 is extended to another one containing it. Every step, the computation is carried out taking advantage of the previous one, what considerably reduces the amount of work. These general results are illustrated with the subspace of matrices M such that AM is symmetric. The main application is developed for the subspace of matrices with a given sparsity pattern which may be constructed iteratively by augmenting the set of non‐zero entries in each column. Finally, the effectiveness of the sparse preconditioners is illustrated with some numerical experiments. Copyright © 2002 John Wiley & Sons, Ltd.
Modelling crack growth by level sets in the extended finite element method
Authors: Stolarska M. , Chopp D. L. , Moës N. , Belytschko T. 
Published: August 2002

AbstractAn algorithm which couples the level set method (LSM) with the extended finite element method (X‐FEM) to model crack growth is described. The level set method is used to represent the crack location, including the location of crack tips. The extended finite element method is used to compute the stress and displacement fields necessary for determining the rate of crack growth. This combined method requires no remeshing as the crack progresses, making the algorithm very efficient. The combination of these methods has a tremendous potential for a wide range of applications. Numerical examples are presented to demonstrate the accuracy of the combined methods. Copyright © 2001 John Wiley & Sons, Ltd.
An updated Lagrangian finite element sensitivity analysis of large deformations using quadrilateral elements
Authors: Srikanth Akkaram , Zabaras Nicholas 
Published: August 2002

AbstractA continuum parameter and shape sensitivity analysis is presented for metal forming processes using the finite element method. The sensitivity problem is posed in a novel updated Lagrangian framework as suitable for very large deformations when remeshing operations are performed during the analysis. In addition to exploring the issue of transfer of variables between meshes for finite deformation analysis, the complex problem of transfer of design sensitivities (derivatives) between meshes for large deformation inelastic analyses is also discussed. A method is proposed that is shown to give accurate estimates of design sensitivities when remeshing operations are performed during the analysis. Sensitivity analysis for the consistent finite element treatment of near incompressibility within the context of the assumed strain methods is also proposed. In particular, the performance of four‐noded quadrilateral elements for the sensitivity analysis of large deformations is studied. The results of the continuum sensitivity analysis are validated by a comparison with those obtained by a finite difference approximation (i.e. using the solution of a perturbed deformation problem). The effectiveness of the method is demonstrated by applications in the design optimization of metal forming processes. Copyright © 2001 John Wiley & Sons, Ltd.
Convergence study of the truncated Karhunen–Loeve expansion for simulation of stochastic processes
Authors: Huang S. P. , Quek S. T. , Phoon K. K. 
Published: August 2002

AbstractA random process can be represented as a series expansion involving a complete set of deterministic functions with corresponding random coefficients. Karhunen–Loeve (K–L) series expansion is based on the eigen‐decomposition of the covariance function. Its applicability as a simulation tool for both stationary and non‐stationary Gaussian random processes is examined numerically in this paper. The study is based on five common covariance models. The convergence and accuracy of the K–L expansion are investigated by comparing the second‐order statistics of the simulated random process with that of the target process. It is shown that the factors affecting convergence are: (a) ratio of the length of the process over correlation parameter, (b) form of the covariance function, and (c) method of solving for the eigen‐solutions of the covariance function (namely, analytical or numerical). Comparison with the established and commonly used spectral representation method is made. K–L expansion has an edge over the spectral method for highly correlated processes. For long stationary processes, the spectral method is generally more efficient as the K–L expansion method requires substantial computational effort to solve the integral equation. The main advantage of the K–L expansion method is that it can be easily generalized to simulate non‐stationary processes with little additional effort. Copyright © 2001 John Wiley & Sons, Ltd.
An analysis for the compressible Stokes equations by first‐order system of least‐squares finite element method
Authors: Kim Sang Dong , Lee EunJung 
Published: August 2002

AbstractThis article applies the first‐order system least‐squares (fosls) finite element method developed by Cai, Manteuffel and McCormick to the compressible Stokes equations. By introducing a new dependent velocity flux variable, we recast the compressible Stokes equations as a first‐order system. Then it is shown that the ellipticity and continuity hold for the least‐squares functionals employing the mixture of H−1 and L2, so that the fosls finite element methods yield best approximations for the velocity flux and velocity. © 2001 John Wiley & Sons, Inc. Numer Methods Partial Differential Eq 17:689–699, 2001
Randomized trial of a home recovery intervention following coronary artery bypass surgery
Authors: Moore Shirley M. , Dolansky Mary A. 
Published: August 2002

AbstractFor this study a randomized clinical trial was designed to test the effects of an early home recovery information intervention on physical functioning, psychological distress, and symptom frequency 1 month following coronary artery bypass graft surgery (CABG). Recovery outcomes were compared between two groups: those receiving an audiotape of information on expected physical sensations and their management (Cardiac Home Information Program [CHIP]) in addition to the usual care, and those receiving the usual cardiac discharge information protocol. A nonprobability sample of 180 patients (84 women and 96 men; mean age = 62 years) was equally distributed between the two study groups. When controlling for age, comorbidity, and cardiac functional status, the results showed positive effects on physical functioning in women and psychological distress, vigor and fatigue in men. Consistent with other studies, women had worse physical functioning and more symptom frequency than men. These findings indicate that the CHIP intervention is an effective method to prepare CABG patients for home recovery. © 2001 John Wiley & Sons, Inc. Res Nurs Health 24: 93–104, 2001