bluuebunny/crossref_metadata_2025_split huggingface dataset:
Kinetics of endothelin‐induced inhibition and glucose permeability of astrocyte gap junctions
Authors: Blomstrand F. , Giaume C. 
Published: April 2006

AbstractGap junctions contribute to important functions of communicating glial cells in brain physiology and pathology. Endothelins (ETs), a vasoactive family of peptides present in the brain, have been described as potent inhibitors of astrocyte gap junctional communication. Through dye‐coupling studies we demonstrate here that this inhibition occurs rapidly and then successively reverses and returns to control levels after 90 min of continuous ET1 or ET3 exposure. In addition, long‐term exposure of cells to ET3, which acts mainly on ETB receptors, also desensitized the acute action of ET1, which was previously shown to act through either ETA or ETB receptor sites, or both. The gap junction blocker carbenoxolone did not show any time‐dependent desensitization and was fully effective also in cultures treated with ETs for prolonged times. The ETs inhibitory effects were partially prevented when blocking pertussis toxin‐sensitive G‐proteins, chelating intracellular Ca2+, or omitting extracellular Ca2+. We further show that ETs modulate gap junction‐mediated transfer of 2‐[N‐(7‐nitrobenz‐2‐oxa‐1,3‐diazol‐4‐Y1)amino]‐2‐deoxyglucose (2‐NBDG), a fluorescent glucose molecule, indicating a role of astrocyte gap junction coupling in metabolic trafficking and suggesting the importance of these peptides in the control of intercellular diffusion of energetic compounds. These findings might have particular relevance in early tissue reactions after various cerebral injuries, which commonly involve increased cerebral ET levels. © 2006 Wiley‐Liss, Inc.
Accumulation of LPS by polyethylene particles decreases bone attachment to implants
Authors: Xing Zhiqing , Pabst Michael J. , Hasty Karen A. , Smith Richard A. 
Published: April 2006

AbstractMolecules absorbed on the surface of particulate wear debris may contribute to inflammatory reactions that lead to aseptic loosening of implants. Lipopolysaccharide (LPS), a bacterial endotoxin, can attach to many biomaterials and stimulate macrophages to secrete osteoclast‐activating cytokines. We tested the adsorption of LPS by polyethylene particles in vitro and examined the biological effects of LPS absorption on bone remodeling around implants in vivo. Polyethylene particles were incubated in radiolabeled LPS solutions, and adsorption of LPS by the particles was quantified by radioassay. Because polyethylene particles are hydrophobic and less dense than water, they floated and clumped when incubated in a water solution of LPS, resulting in low adsorption of LPS. However, when particles were incubated in an ethanol solution of LPS, most of the LPS was adsorbed by the particles, and was resistant to washing with water. Triton X‐100 (10%), however, effectively washed the LPS off the particles. In a rat model, the presence of polyethylene particles around the implant in the femoral canal decreased bone attachment to the implant at 6 weeks. Incubating the particles with LPS before implantation, or intermittent administration of LPS systemically, further decreased bone–implant attachment to similar extents, but had no effect on the bone density of the control side femurs. Our data indicate that polyethylene particles have high affinity for LPS, depending on many factors, especially the solvents of the LPS. Intermittent systemic administration of LPS affects bone remodeling but only occurs in the area containing polyethylene particles and titanium implants, supporting the hypothesis that the presence of polyethylene particles around implants can result in accumulation of LPS from exogenous sources. This may cause local levels of LPS that are high enough to affect bone remodeling around implants. © 2006 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res
Effective therapy of transected quadriceps muscle in rat: Gastric pentadecapeptide BPC 157
Authors: Staresinic Mario , Petrovic Igor , Novinscak Tomislav , Jukic Ivana , Pevec Damira , Suknaic Slaven , Kokic Neven , Batelja Lovorka , Brcic Luka , Boban‐Blagaic Alenka , Zoric Zdenka , Ivanovic Domagoj , Ajduk Marko , Sebecic Bozidar , Patrlj Leonardo , Sosa Tomislav , Buljat Gojko , Anic Tomislav , Seiwerth Sven , Sikiric Predrag 
Published: April 2006

AbstractWe report complete transection of major muscle and the systemic peptide treatment that induces healing of quadriceps muscle promptly and then maintains the healing with functional restoration. Initially, stable gastric pentadecapeptide BPC 157 (GEPPPGKPADDAGLV, M.W. 1419, PL‐10, PLD‐116, PL 14736 Pliva, Croatia; in trials for inflammatory bowel disease; wound treatment; no toxicity reported; effective alone without carrier) also superiorly accelerates the healing of transected Achilles tendon. Regularly, quadriceps muscle completely transected transversely 1.0 cm proximal to patella presents a definitive defect that cannot be compensated in rat. BPC 157 (10 µg, 10 ng, 10 pg/kg) is given intraperitoneally, once daily; the first application 30 min posttransection, the final 24 h before sacrifice. It consistently improves muscle healing throughout the whole 72‐day period. Improved are: (i) biomechanic (load of failure increased); (ii) function (walking recovery and extensor postural thrust/motor function index returned toward normal healthy values); (iii) microscopy/immunochemistry [i.e., mostly muscle fibers connect muscle segments; absent gap; significant desmin positivity for ongoing regeneration of muscle; larger myofibril diameters on both sides, distal and proximal (normal healthy rat‐values reached)]; (iv) macroscopic presentation (stumps connected; subsequently, atrophy markedly attenuated; finally, presentation close to normal noninjured muscle, no postsurgery leg contracture). Thus, posttransection healing—consistently improved—may suggest this peptide therapeutic application in muscle disorders. © 2006 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res
Effect of aging and degeneration on disc volume and shape: A quantitative study in asymptomatic volunteers
Authors: Pfirrmann Christian W. A. , Metzdorf Alexander , Elfering Achim , Hodler Juerg , Boos Norbert 
Published: April 2006

AbstractDebate continues on the effect of disc degeneration and aging on disc volume and shape. So far, no quantitative in vivo MRI data is available on the factors influencing disc volume and shape. The objective of this MRI study was to quantitatively investigate changes in disc height, volume, and shape as a result of aging and/or degeneration omitting pathologic (i.e., painful) disc alterations. Seventy asymptomatic volunteers (20–78 years) were investigated with sagittal T1‐ and T2‐weighted MR‐images encompassing the whole lumbar spine. Disc height was determined by the Dabbs method and the Farfan index. Disc volume was calculated by the Cavalieri method. For the disc shape the “disc convexity index” was calculated by the ratio of central disc height and mean anterior/posterior disc height. Disc height, disc volume, and the disc convexity index measurements were corrected for disc level and the individuals age, weight, height, and sex in a multilevel regression analysis. Multilevel regression analysis showed that disc volume was negatively influenced by disc degeneration (p < 0.001) and positively correlated with body height (p < 0.001) and age (p < 0.01). Mean disc height and the disc convexity index were negatively influenced by disc degeneration but not by gender, weight, and height. Disc height was positively correlated with age (p < 0.01). From the results of this study, it can be concluded that disc degeneration generally results in a decrease of disc height and volume as well as a less convex disc shape. In the absence of disc degeneration, however, age tends to result in an inverse relationship on disc height, volume, and shape. © 2006 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res
Six DOF in vivo kinematics of the ankle joint complex: Application of a combined dual‐orthogonal fluoroscopic and magnetic resonance imaging technique
Authors: de Asla Richard J. , Wan Lu , Rubash Harry E. , Li Guoan 
Published: April 2006

AbstractAccurate knowledge of in vivo ankle joint complex (AJC) biomechanics is critical for understanding AJC disease states and for improvement of surgical treatments. This study investigated 6 degrees‐of‐freedom (DOF) in vivo kinematics of the human AJC using a combined dual‐orthogonal fluoroscopic and magnetic resonance imaging (MRI) technique. Five healthy ankles of living subjects were studied during three in vivo activities of the foot, including maximum plantarflexion and dorsiflexion, maximum supination and pronation, and three weight‐bearing positions in simulated stance phases of walking. A three‐dimensional (3D) computer model of the AJC (including tibia, fibula, talus, and calcaneus) was constructed using 3D MR images of the foot. The in vivo AJC position at each selected position of the foot was captured using two orthogonally positioned fluoroscopes. In vivo AJC motion could then be reproduced by coupling the orthogonal images with the 3D AJC model in a virtual dual‐orthogonal fluoroscopic system. From maximum dorsiflexion to plantarflexion, the arc of motion of the talocrural joint (47.5 ± 2.2°) was significantly larger than that of the subtalar joint (3.1 ± 6.8°). Both joints showed similar degrees of internal–external and inversion–eversion rotation. From maximum supination to pronation, all rotations and translations of the subtalar joint were significantly larger than those of the talocrural joint. From heel strike to midstance, the plantarflexion contribution from the talocrural joint (9.1 ± 5.3°) was significantly larger than that of the subtalar joint (−0.9 ± 1.2°). From midstance to toe off, internal rotation and inversion of the subtalar joint (12.3 ± 8.3° and −10.7 ± 3.8°, respectively) were significantly larger than those of the talocrural joint (−1.6 ± 5.9° and −1.7 ± 2.7°). Strong kinematic coupling between the talocrural and subtalar joints was observed during in vivo AJC activities. The contribution of the talocrural joint to active dorsi‐plantarflexion was higher than that of the subtalar joint, whereas the contribution of the subtalar joint to active supination–pronation was higher than that of the talocrural joint. In addition, the talocrural joint demonstrated larger motion during the early part of stance phase while the subtalar joint contributes more motion during the later part of stance phase. The results add quantitative data to an in vivo database of normals that can be used in clinical diagnosis, treatment, and evaluation of the AJC after injuries. © 2006 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res
Kinetics and mechanism of the oxidative regeneration of carbonyl compounds from oximes by pyridinium bromochromate
Authors: Sharma Pradeep K. 
Published: April 2006

AbstractThe oxidative deoximination of several aldo‐ and keto‐oximes by pyridinium bromochromate (PBC), in dimethylsulfoxide, exhibited a first‐order dependence on both the reductant (oxime) and the oxidant (PBC). The oxidation of ketoximes is slower than that of aldoximes. The rates of oxidation of aldoximes correlated well in terms of the Pavelich–Taft dual substituent‐parameter equation. The low positive value of polar reaction constant indicated a nucleophilic attack by a chromate‐oxygen on the carbon. The reaction is subject to steric hindrance by the alkyl groups. The reaction of acetaldoxime has been studied in 19 different organic solvents. The solvent effect has been analyzed by Taft's and Swain's multiparametric equations. A mechanism involving the formation of a cyclic intermediate, in the rate‐determining step, has been proposed. © 2006 Wiley Periodicals, Inc. Int J Chem Kinet 38: 364–368, 2006
Complete assignments of 1H and 13C NMR spectral data for a novel diterpenoid from Semiaquilegia adoxoides
Authors: Niu Feng , Cui Zheng , Li Qin , Chang Haitao , Jiang Yong , Qiao Liang , Tu Peng‐fei 
Published: April 2006

AbstractSemiaquilegoside A (1), a new diterpenoid, was isolated from the roots of Semiaquilegia adoxoides. Its chemical structure was established as 3β, 11‐ dihydroxy‐12‐O‐β‐D‐glucopyranosyl‐8,11,13‐abietatrien‐6‐one through spectroscopic techniques and chemical analysis. Copyright © 2006 John Wiley & Sons, Ltd.
Multifocal acquired demyelinating sensory and motor neuropathy presenting as a peripheral nerve tumor
Authors: Allen David C. , Smallman Clare A. , Mills Kerry R. 
Published: April 2006

AbstractA man with multifocal acquired demyelinating sensory and motor neuropathy (MADSAM), or Lewis–Sumner syndrome, presented with a progressive left lumbosacral plexus lesion resembling a neurofibroma. After 7 years he developed a left ulnar nerve lesion with conduction block in its upper segment. Treatment with intravenous immunoglobulin improved the symptoms and signs of both lesions. We conclude that inflammatory neuropathy must be considered in the differential diagnosis of peripheral nerve tumors, and that unifocal lesions may precede multifocal involvement in MADSAM by several years. In addition, we discuss the clinical features in 9 patients attending a specialist peripheral nerve clinic and review the literature. Muscle Nerve, 2006
A case of Lewis–Sumner syndrome with conduction abnormalities only in the brachial plexus and roots
Authors: Dionne Annie , Brunet Denis 
Published: April 2006

AbstractWe present a case of subacute weakness of one hand with unusual sensory involvement including the upper thorax. Despite normal distal conduction studies, a clinical diagnosis of Lewis–Sumner syndrome was made and the patient responded well to intravenous immunoglobulins. Repeated studies after clinical exacerbation finally proved the demyelinating nature of the neuropathy using proximal magnetic nerve stimulation. This case underlies the importance of seeking proximal conduction blocks in patients with suspected demyelinating neuropathy. Muscle Nerve, 2006
Interrater reliability of the needle examination in lumbosacral radiculopathy
Authors: Kendall Richard , Werner Robert A. 
Published: April 2006

AbstractLow back pain and lumbar radiculopathy are among the most common painful disorders affecting the adult population. This study hypothesizes that there is good correlation between the diagnostic impression of an unblinded electromyographer, using clinical and electromyographic information, and an independent electromyographer, who uses the needle examination only to assess for lumbar radiculopathy. This is a prospective, single‐blinded, observational pilot study. The needle examination was electronically recorded, reproduced, and shown to a second examiner, blinded to all clinical data. Diagnostic impressions from both examiners were recorded and evaluated for agreement. Six recorded cases were reviewed by 66 blinded examiners. Overall diagnostic agreement was 46.9% (60.5% faculty level, 28.5% resident level). Logistic regression shows a strong association between training level and agreement on diagnostic impression (odds ratio, 1.9; 95% confidence interval, 1.12–3.22; P = 0.019). This study shows that there is fair interrater reliability between faculty‐level examiners and poor reliability among resident‐level examiners when the needle examination is used to evaluate patients with lumbar radiculopathy. Muscle Nerve, 2006
Inappropriate surgeries resulting from misdiagnosis of early amyotrophic lateral sclerosis
Authors: Srinivasan Jayashri , Scala Stephanie , Jones H. Royden , Saleh Firas , Russell James A. 
Published: April 2006

AbstractInitial symptoms of amyotrophic lateral sclerosis (ALS) may mimic radiculopathy, myelopathy, mononeuropathy, or arthropathy. A retrospective review of 260 consecutive patients with ALS evaluated between 1996 and 2004 revealed that 55 (21%) had had surgery within the 5 years prior to ALS diagnosis. Thirty‐four of these 55 (61%) had surgery for symptoms and signs that retrospectively were attributable to early manifestations of ALS. Misdiagnosis of early ALS may lead to unnecessary surgeries with their attendant potential complications. Muscle Nerve, 2006
The Characteristic‐Based Split (CBS) scheme—a unified approach to fluid dynamics
Authors: Nithiarasu P. , Codina R. , Zienkiewicz O. C. 
Published: April 2006

AbstractThis paper presents a comprehensive overview of the characteristic‐based methods and Characteristic‐Based Split (CBS) scheme. The practical difficulties of employing the original characteristic schemes are discussed. The important features of the CBS scheme are brought out by studying several problems of compressible and incompressible flows. All special consideration necessary for solving these problems are thoroughly discussed. The CBS scheme is presented in such a way that any interested researcher should be able to develop a code using the information provided. Several invicid and viscous flow examples are also provided to demonstrate the unified CBS approach. For sample two‐dimensional codes, input files and instructions, the readers are referred to ‘www.nithiarasu.co.uk’ Copyright © 2006 John Wiley & Sons, Ltd.
Charge distribution on thin conducting nanotubes—reduced 3‐D model
Authors: Chen Hui , Mukherjee Subrata 
Published: April 2006

AbstractThe subject of this paper is the calculation of charge distribution on the surfaces of thin conducting nanotubes in electrostatic problems, by the boundary element method (BEM). A line model of a nanotube is proposed here. This model overcomes the problem of dealing with nearly singular matrices that occur when the standard BEM is applied to very thin features (objects or gaps). This new approach is also very efficient. Numerical results are presented for selected examples. Copyright © 2006 John Wiley & Sons, Ltd.
Accelerating iterative solution methods using reduced‐order models as solution predictors
Authors: Markovinović R. , Jansen J. D. 
Published: April 2006

AbstractWe propose the use of reduced‐order models to accelerate the solution of systems of equations using iterative solvers in time stepping schemes for large‐scale numerical simulation. The acceleration is achieved by determining an improved initial guess for the iterative process based on information in the solution vectors from previous time steps. The algorithm basically consists of two projection steps: (1) projecting the governing equations onto a subspace spanned by a low number of global empirical basis functions extracted from previous time step solutions, and (2) solving the governing equations in this reduced space and projecting the solution back on the original, high dimensional one. We applied the algorithm to numerical models for simulation of two‐phase flow through heterogeneous porous media. In particular we considered implicit‐pressure explicit‐saturation (IMPES) schemes and investigated the scope to accelerate the iterative solution of the pressure equation, which is by far the most time‐consuming part of any IMPES scheme. We achieved a substantial reduction in the number of iterations and an associated acceleration of the solution. Our largest test problem involved 93 500 variables, in which case we obtained a maximum reduction in computing time of 67%. The method is particularly attractive for problems with time‐varying parameters or source terms. Copyright © 2006 John Wiley & Sons, Ltd.
A new finite element formulation for internal acoustic problems with dissipative walls
Authors: Larbi W. , Deü J.‐F. , Ohayon R. 
Published: April 2006

AbstractThis work concerns the variational formulation and the numerical computation of internal acoustic problems with absorbing walls. The originality of the proposed approach, compared to other existing methods, is the introduction of the normal fluid displacement field on the damped walls. This additional variable allows to transpose formulations in frequency domain to time domain when the fluid is described by a scalar field (pressure or fluid displacement potential). With this new scalar unknown, various absorbing wall models can be introduced in the variational formulation. Moreover, the associated finite element matrix system in symmetric form can be solved in frequency and time domain. Copyright © 2006 John Wiley & Sons, Ltd.
Combining interface damage and friction in a cohesive‐zone model
Authors: Alfano Giulio , Sacco Elio 
Published: April 2006

AbstractA new method to combine interface damage and friction in a cohesive‐zone model is proposed. Starting from the mesomechanical assumption, typically made in a damage‐mechanics approach, whereby a representative elementary area of the interface can be additively decomposed into an undamaged and a fully damaged part, the main idea consists of assuming that friction occurs only on the fully damaged part. The gradual increase of the friction effect is then a natural outcome of the gradual increase of the interface damage from the initial undamaged state to the complete decohesion. Suitable kinematic and static hypotheses are made in order to develop the interface model whereas no special assumptions are required on the damage evolution equations and on the friction law. Here, the Crisfield's interface model is used for the damage evolution and a simple Coulomb friction relationship is adopted. Numerical and analytical results for two types of constitutive problem show the effectiveness of the model to capture all the main features of the combined effect of interface damage and friction. A finite‐step interface law has then been derived and implemented in a finite‐element code via interface elements. The results of the simulations made for a fibre push‐out test and a masonry wall loaded in compression and shear are then presented and compared with available experimental results. They show the effectiveness of the proposed model to predict the failure mechanisms and the overall structural response for the analysed problems. Copyright © 2006 John Wiley & Sons, Ltd.
A parallel hp‐FEM infrastructure for three‐dimensional structural acoustics
Authors: Dey Saikat , Datta Dibyendu K. 
Published: April 2006

AbstractThis paper describes a parallel three‐dimensional numerical infrastructure for the solution of a wide range of time‐harmonic problems in structural acoustics and vibration. High accuracy and rate of error‐convergence, in the mid‐frequency regime,is achieved by the use of hp‐finite and infinite element approximations. The infrastructure supports parallel computation in both single and multi‐frequency settings. Multi‐frequency solves utilize concurrent factoring of the frequency‐dependent linear algebraic systems and are naturally scalable. Scalability of large‐scale single‐frequency problems is realized by using FETI‐DP—an iterative domain‐decomposition scheme.Numerical examples are presented to cover applications in vibratory response of fluid‐filled elastic structures as well as radiation and scattering from elastic structures submerged in an infinite acoustic medium. We demonstrate both the numerical accuracy as well as parallel scalability of the infrastructure in terms of problem parameters that include wavenumber and number of frequencies, polynomial degree of finite/infinite element approximations as well as the number of processors. Scalability and accuracy is evaluated for both single and multiple frequency sweeps on four high‐performance parallel computing platforms: SGI Altix, SGI Origin, IBM p690 SP and Linux‐cluster. Results show good performance on shared as well as distributed‐memory architecture. Copyright © 2006 John Wiley & Sons, Ltd.