bluuebunny/crossref_metadata_2025_split huggingface dataset:
Improvement of double pulsed field gradient spin‐echo ROESY experiments for identification of bound waters
Authors: Furihata Kazuo , Shimotakahara Sakurako , Tashiro Mitsuru 
Published: October 2003

AbstractA novel pulse sequence incorporating the double pulsed field gradient spin‐echo (DPFGSE) and the gradient‐tailored excitation WATERGATE techniques is presented that has particular use for identifying bound waters in 15N‐labeled macromolecules. This sequence, DPFGSE–ROESY–HSQC, affords greater spectral sensitivity than the DPFGSE–ROESY–HMQC experiment which was previously presented and is consequently useful for rapidly obtaining reliable information for characterizing macromolecular bound water molecules. A significant enhancement in the sensitivity is achieved by using the gradient‐tailored excitation WATERGATE sequence in the reverse INEPT step as it allows the use of much higher receiver gains. Since coherence selection is not used, the sequence has improved sensitivity together with less spectral artifacts. The advantage of this pulse sequence is illustrated using 15N‐labeled ribonuclease T1. Copyright © 2003 John Wiley & Sons, Ltd.
Theoretical study on 19F magnetic shielding constants of some metal fluorides
Authors: Cai Shu‐Hui , Yu Xian‐Yong , Chen Zhong , Wan Hui‐Lin 
Published: October 2003

AbstractA study is presented of 19F NMR magnetic shielding constants of MF2 (M = Zn, Cd), β‐PbF2, MF3 (M = Al, Ga, In), AMF3 (A = K, Rb, Cs, Ba; M = Mg, Ca, Li, Zn, Cd), BaMgF4, BaZnF4 and Ba2ZnF6 using the DFT/GIAO method. The aug‐cc‐pVTZ basis set was used for the fluorine atom under investigation and LanL2DZ for the remaining fluorine atoms. The 3–21G(2d) basis set was used for the aluminum atom and CRENBL for the other metal atoms. When appropriate cluster models were employed, the theoretical results obtained from the B3LYP/GIAO calculations are in good agreement with experimental measurements and may be better than those obtained from empirical calculations. The correlation coefficient and the slope of the fitting line between our theoretical predictions and the experimental observations are close to unity. Copyright © 2003 John Wiley & Sons, Ltd.
Spin label study of phase morphology and polymer segmental motion in poly(acrylic acid)–poly(ethylene oxide) complex
Authors: Tan Li , Lu Guangqiang , Chen Shiming , Ping Zhenghua , Shen Yimin 
Published: October 2003

AbstractThe ESR lineshapes of nitroxide radical end‐labeled on poly(ethylene oxide) (SLPEO) for the pure polymer and for different weight ratio complexes with poly(acrylic acid) (PAA) were studied as a function of temperature. For SLPEO one spectral component was detected in the entire temperature range, indicating that the spin label was in the homogeneous phase domain. For all PAA–PEO complexes two spectral components with different rates of motion, a ‘fast’ and a ‘slow’ component, were observed, which indicates the existence of microheterogeneity at the molecular level: the more mobile the PEO‐rich microphase, the more rigid is the PAA‐rich microphase. On the other hand, the SLPEO polymer segmental motion was restricted owing to the hydrogen bond interaction between the carboxyl proton in PAA and the ether oxygen in PEO. This restriction was exacerbated with increasing the PAA content in the complex, which could be further substantiated through the calculated S and τc values. Copyright © 2003 John Wiley & Sons, Ltd.
Two new asterosaponins from the starfish Asterias rubens: application of a cryogenic NMR probe head
Authors: Sandvoss M. , Preiss A. , Levsen K. , Weisemann R. , Spraul M. 
Published: October 2003

AbstractWe report two new asterosaponins from the Baltic starfish Asterias rubens along with their 1H and 13C NMR data. The compounds were isolated after on‐flow liquid chromatography–NMR–mass spectrometry screening indicated that they had not been identified before. The one‐ and two‐dimensional NMR experiments used to elucidate the structures were recorded using a 5 mm cryogenic probe head. The advantages of cryogenic probes for this kind of examination in comparison with conventional probe heads are discussed. Copyright © 2003 John Wiley & Sons, Ltd.
Multiple quantum NMR spectra of toluene and p‐bromotoluene partially aligned in a nematic phase
Authors: Field Leslie D. , Ramadan Saadallah A. 
Published: October 2003

Abstract1H multiple quantum (MQ) NMR spectra of toluene and p‐bromotoluene, partially aligned in a liquid crystalline solvent, were acquired using gradient‐assisted methods. The MQ spectra were analysed to give the dipolar couplings (Dij) and these were used to determine the molecular shape and average orientation of the of the spin systems. Copyright © 2003 John Wiley & Sons, Ltd.
Solid‐state NMR characterization of oxygen sites in organically modified aluminosilicate xerogels
Authors: Lafuma Aurélie , Fayon Franck , Massiot Dominique , Chodorowski‐Kimmès Sandrine , Sanchez Clément 
Published: October 2003

AbstractSolid‐state NMR characterization of hybrid aluminosilicate xerogels, by 17O magic angle spinning (MAS) and triple quantum magic angle spinning (MQMAS) techniques, evidences Si—O—Si and Si—O—Al oxygen sites, spectrally separated in MQMAS experiments. Inversion of the MQMAS spectra allows the measurement of quadrupolar parameters, isotropic chemical shifts, distribution of chemical shift and discussion of the mobility of the structural units. Copyright © 2003 John Wiley & Sons, Ltd.
Acetylcholine receptor distribution and synapse elimination at the developing neuromuscular junction of mdx mice
Authors: Minatel Elaine , Neto Humberto Santo , Marques Maria Julia 
Published: October 2003

AbstractThe pattern of innervation of the vertebrate neuromuscular junction is established during early development, when junctions go from multiple to single innervation in the phenomenon of synapse elimination, suggesting that changes at the molecular level in the postsynaptic cell lead to the removal of nerve terminals. The mdx mouse is deficient in dystrophin and associated proteins that are part of the postsynaptic cytoskeleton. We used rhodamine‐α‐bungarotoxin and anti‐neurofilament IgG–FITC to stain acetylcholine receptors and nerve terminals of the sternomastoid muscle during postnatal development in mdx and control C57BL/10 mice. Using fluorescence confocal microscopy, we observed that, 7 days after birth, 86.7% of the endplates of mdx mice were monoinnervated (n = 200) compared with 41.4% in control mice (n = 200). By the end of the second postnatal week, all endplates were innervated singly (100% mdx and 94.7% controls, n = 200 per group). These results show that dystrophic fibers achieve single innervation earlier, perhaps because dystrophin or a normal cytoskeletal complex is implicated in this phenomenon. Muscle Nerve 28: 561–569, 2003
X‐linked motor and sensory neuropathy with pyramidal signs and cerebral white matter lesions
Authors: Goto Hirofumi , Matsuo Hidenori , Ohnishi Akio , Fukudome Takayasu , Shibuya Noritoshi 
Published: October 2003

AbstractWe report two brothers with hereditary motor and sensory neuropathies and pyramidal signs. Electrophysiological evaluation revealed polyneuropathy and involvement of the central motor, somatosensory, and auditory pathways. Brain magnetic resonance imaging studies showed diffuse white matter lesions, and sural nerve biopsy identified a reduction in the large myelinated nerve fibers. The patients' mother and sister exhibited similar, but milder neurologic findings suggesting that the genetic defect may be X‐linked; however, a point mutation in the connexin 32 gene was negative. Muscle Nerve 28: 623–625, 2003
Mononeuropathy multiplex in association with livedoid vasculitis
Authors: Toth Cory , Trotter Martin , Clark Arthur , Zochodne Douglas 
Published: October 2003

AbstractLivedoid vasculitis is a chronic dermatological disorder associated with petechiae and recurrent, unusually shaped ulcers that heal to form hyperpigmentated areas and atrophie blanche. This condition is more correctly termed a vasculopathy, rather than a vascultis, and is often associated with an underlying hypercoagulable disorder. We report a patient with livedoid vasculitis and mononeuropathy multiplex. We propose that peripheral nervous system involvement arises from multifocal areas of ischemia due to fibrin and thrombin deposition within both the wall and lumen of vasa nervorum. Muscle Nerve 28: 634–639, 2003
McArdle's disease presenting as recurrent cryptogenic renal failure due to occult seizures
Authors: Walker Adrianne R. , Tschetter Kevin , Matsuo Fumisuke , Flanigan Kevin M. 
Published: October 2003

AbstractMyophosphorylase deficiency (McArdle's disease) may present with episodic renal failure following exertion. We present a case of adult‐onset myophosphorylase deficiency in which recurrent bouts of renal failure could not be associated with any exertional events until a tonic seizure was witnessed after the fourth episode of renal failure. In the absence of a clear exertional cause for myoglobinuria, an occult seizure disorder should be suspected. Muscle Nerve 28: 640–643, 2003
Clinical and neurophysiological evaluation of progression in amyotrophic lateral sclerosis
Authors: de Carvalho Mamede , Scotto Manuel , Lopes Arminda , Swash Michael 
Published: October 2003

AbstractThere is a need for a sensitive neurophysiological measure of disease progression in following the course of patients with amyotrophic lateral sclerosis (ALS). We studied two groups of nine ALS patients, one with slow progression (Group A) and the other with rapid progression (Group B). We evaluated muscle strength scores using the Medical Research Council (MRC) scale in limb and trunk muscles, forced vital capacity (FVC), and ALS functional rating scale (ALS‐FRS) scores. Maximal voluntary isometric contraction (MVIC) of the abductor digiti minimi muscle (ADM) was measured, using a digital device. We also measured M‐wave amplitude and area in the ADM, and the distal motor latency and F‐wave frequency in the ulnar nerve; from these data, the neurophysiological index (NI) was calculated, as described previously. In both groups, the NI was the most sensitive measure of change, with the smallest coefficient of variation. We conclude that the NI, which requires no special technology and no new clinical or technical skills to use, is sensitive to change, and therefore may be useful in clinical trials, as well as in a clinical setting. Muscle Nerve 28: 630–633, 2003
Positive salivary gland biopsy, Sjögren syndrome, and neuropathy: Clinical implications
Authors: Gorson Kenneth C. , Ropper Allan H. 
Published: October 2003

AbstractThe relationship between neuropathy and Sjögren syndrome has been predicated largely on sicca symptoms or serological abnormalities rather than salivary gland pathology. We reviewed consecutive neuropathy patients who had had a lip biopsy to identify features of the neuropathy that were associated with a positive lip biopsy suggesting Sjögren syndrome. Twenty of 54 neuropathy patients were biopsy positive; 13 had a painful or nonspecific sensory neuropathy and only 4 were ataxic. Sicca symptoms were not associated with a positive biopsy (P = 0.14). Serological abnormalities were found more often in the biopsy‐positive group (P = 0.008), but anti–Sjögren syndrome A or B (anti‐SSA or SSB) antibodies were detected in only 30%. There were no other clinical or electromyographic (EMG) features associated with a positive biopsy. From this experience, we conclude that: (1) most patients with neuropathy and a positive lip biopsy for Sjögren syndrome have a painful, distal, sensory axonal neuropathy; (2) there are no clinical or EMG features that are predictive of a positive lip biopsy; (3) ataxic neuropathy is uncommon; and (4) the lack of sicca symptoms or anti‐SSA or SSB antibodies in patients with neuropathy does not exclude Sjögren syndrome based upon salivary gland pathology. Muscle Nerve 28: 553–560, 2003
Clinical study of fk506 in patients with myasthenia gravis
Authors: Konishi Tetsuro , Yoshiyama Yasumasa , Takamori Masaharu , Yagi Koichi , Mukai Eiichiro , Saida Takahiko ,   The Japanese FK506 MG Study Group
Published: October 2003

AbstractTo investigate the usefulness of low‐dose FK506 for the treatment of myasthenia gravis (MG), we treated 19 patients with generalized MG in a 16‐week open clinical trial of FK506 (3–5 mg/day). At the end of the trial, total MG scores (range: 0–27 points) improved by 3 points or more in 7 of 19 patients (37%), and activities of daily living (ADL) scores (range: 0–6 points) also improved by 1 point or more in 8 of 19 patients (42%). Nine of 19 patients (47%) showed improvement in either MG or ADL scores. Significant reduction of anti‐acetylcholine receptor antibody titers and interleukin 2 production were observed at the end of this study. Minor but commonly observed side effects were an increase in neutrophil count and a decrease in lymphocyte count. No serious adverse events such as renal toxicity or diabetes mellitus were observed during the 16‐week treatment period. FK506 could safely serve as an adjunct to steroid therapy for MG at low dosage. Muscle Nerve 28: 570–574 2003
Differential responses of HSPs to heat stress in slow and fast regions of rat gastrocnemius muscle
Authors: Oishi Yasuharu , Taniguchi Kouhachi , Matsumoto Hisahiro , Ishihara Akihiko , Ohira Yoshinobu , Roy Roland R. 
Published: October 2003

AbstractIn a recent study, we showed that the rat slow soleus and fast plantaris muscles exhibited different time courses for the response of specific heat shock proteins (HSPs) after 1 h of heat stress. We hypothesized that these differential responses were related, in part, to the varying fiber type composition of these muscles. To further test this hypothesis, we now have determined the responses of Hsp60, Hsp72, and Hsc73 during the 60 h following exposure to a single bout of heat stress in the deep (relatively high percentage of slow fibers) and superficial regions (only fast fibers) of the adult rat gastrocnemius muscle. The temperature of the musculature in the left hindlimb was elevated to ∼42°C for 1 h, while the right hindlimb served as a control. Two hours after the heat stress, the Hsp60 levels were increased by 1.3‐ and 2.0‐fold in the deep and superficial regions, respectively. The Hsp72 levels were increased (1.8‐fold) in the deep region at 8 h after heat stress, whereas in the superficial region these levels were increased between 4 and 48 h (peak at 36 h by 10‐fold) after the heat stress. No changes were observed for Hsc73 in either region of the muscle. Combined with our previous data, the results indicate that the responses of HSPs in the rat hindlimb muscles after a single exposure to heat stress are related to fiber type composition of the muscle or muscle region or to the inherent properties of each HSP. From a clinical viewpoint, these data indicate that specific regions (most likely based on fiber type composition) within a muscle may be affected differentially by any intervention inducing HSPs. Muscle Nerve 28: 587–594, 2003
Autonomic and peripheral neuropathy in endstage liver disease and following liver transplantation
Authors: McDougall Alan J. , Davies Leo , McCaughan Geoff W. 
Published: October 2003

AbstractSevere chronic liver disease may be associated with a peripheral somatic and an autonomic neuropathy. There are only a limited number of reports on the incidence and features of these neuropathies. In addition the effects of liver transplantation on these neuropathies have not been well studied. We examined peripheral somatic and autonomic nerve function in 42 patients with endstage liver disease prior to transplantation and also examined the effect of liver transplantation on these neuropathies in 14 patients. Peripheral somatic neuropathy (93%) and autonomic neuropathy (50%) were common in patients with endstage liver disease and were more frequent than previously reported. Abnormalities improved in some patients after liver transplantation, particularly if there was return of normal hepatic function. Muscle Nerve 28: 595–600, 2003
Acute leg‐cycling exercise attenuates the h‐reflex recorded in soleus but not flexor carpi radialis
Authors: Motl Robert W. , Dishman Rod K. 
Published: October 2003

AbstractThe amplitude of the Hoffman reflex (H‐reflex) in the soleus muscle is attenuated after acute bouts of leg‐cycling exercise. The attenuation has been interpreted as a “tranquilizing” effect of exercise controlled by the central nervous system and generalized beyond a single spinal segmental level. If so, the postexercise depression of the H‐reflex should occur in both the soleus and the flexor carpi radialis (FCR) muscle, which is not actively involved during leg cycling. This experiment examined the effect of moderate‐intensity cycling exercise on the H‐reflex recorded in soleus and FCR among 16 men. The H‐reflex was measured immediately before and 10 min after 30 min of either moderate‐intensity leg cycling (60% V̇O2peak) or quiet rest. The acute bout of cycling exercise reduced the H‐reflex in the soleus but not in the FCR. Thus, the attenuation of the H‐reflex after leg cycling does not generalize beyond the spinal segmental level that modulates the involved locomotory muscles; it is likely the result of segmental processes associated with the repetitive stretching or activation of the soleus muscle. Muscle Nerve 28: 609–613, 2003
An improvement on perturbation bounds for the Drazin inverse
Authors: Wei Yimin , Li Xiezhang 
Published: October 2003

AbstractThe Drazin inverse of a square matrix occurs in a number of applications. It is of importance to analyse the perturbation bounds for the Drazin inverse of a matrix. Let B=A+E. Under the assumption of rank(Bj) =rank(Ak), where j and k are the indices of B and A, respectively, upper bounds of ∥BD‐AD∥/∥AD∥ and ∥BBD‐AAD∥/∥AAD∥ have been recently studied. However, these upper bounds do not cover the perturbation bounds of the group inverse recently given by the authors as a special case.Moreover, these perturbation bounds for the Drazin inverse are too large to be practical. In this paper, we present sharper unified perturbation bounds for the Drazin inverse, which are the extensions of the recent result in the case of group inverse. It solves the problem posed by Campbell and Meyer in 1975. A numerical example is given to illustrate the sharpness of the new general bounds. Copyright © 2003 John Wiley & Sons, Ltd.
On the stability of the computation of the stationary probabilities of Markov chains using Perron complements
Authors: Neumann Michael , Xu Jianhong 
Published: October 2003

AbstractFor an n‐state ergodic homogeneous Markov chain whose transition matrix is T∈ℝn,n, it has been shown by Meyer on the one hand and by Kirkland, Neumann, and Xu on the other hand that the stationary distribution vector and that the mean first passage matrix, respectively, can be computed by a divide and conquer parallel method from the Perron complements of T. This is possible due to the facts, shown by Meyer, that the Perron complements of T are themselves transition matrices for finite ergodic homogeneous Markov chains with fewer states and that their stationary distribution vectors are multiples of the corresponding subvectors of the stationary distribution vector of the entire chain.Here we examine various questions concerning the stability of computing the stationary distribution vectors of the Perron complements and compare them with the stability of computing the stationary distribution vector for the entire chain. In particular, we obtain that condition numbers which are related to the coefficients of ergodicity improve as we pass from the entire chain to the chains associated with its Perron complements. Copyright © 2003 John Wiley & Sons, Ltd.
Convergence of a balancing domain decomposition by constraints and energy minimization
Authors: Mandel Jan , Dohrmann Clark R. 
Published: October 2003

AbstractA convergence theory is presented for a substructuring preconditioner based on constrained energy minimization concepts. The substructure spaces consist of local functions with zero values of the constraints, while the coarse space consists of minimal energy functions with the constraint values continuous across substructure interfaces. In applications, the constraints include values at corners and optionally averages on edges and faces. The preconditioner is reformulated as an additive Schwarz method and analysed by building on existing results for balancing domain decomposition. The main result is a bound on the condition number based on inequalities involving the matrices of the preconditioner. Estimates of the form C(1+log2(H/h)) are obtained under the standard assumptions of substructuring theory. Computational results demonstrating the performance of method are included. Published in 2003 by John Wiley & Sons, Ltd.
Algorithms for automated meshing and unit cell analysis of periodic composites with hierarchical tri‐quadratic tetrahedral elements
Authors: Kim Hyung Joo , Swan Colby C. 
Published: October 2003

AbstractUnit cell homogenization techniques together with the finite element method are very effective for computing equivalent mechanical properties of composites and heterogeneous materials systems. For systems with very complicated material arrangements, traditional, manual mesh generation can be a considerable obstacle to usage of these techniques. This problem is addressed here by developing automated meshing techniques that start from a hierarchical quad‐tree (in 2D) or oc‐tree (in 3D) mesh of pixel or voxel elements. From the pixel/voxel mesh, algorithms are presented for successive element splitting and nodal shifting to arrive at final meshes that accurately capture both material arrangements and constituent volume fractions, and the material‐scale stress and strain fields within the composite under different modalities of loading. The performance and associated convergence behaviour of the proposed techniques are demonstrated on both densely packed fibre and particulate composites, and on 3D textile‐reinforced composites. Copyright © 2003 John Wiley Sons, Ltd.
A novel unsymmetric 8‐node plane element immune to mesh distortion under a quadratic displacement field
Authors: Rajendran S. , Liew K. M. 
Published: October 2003

AbstractAn 8‐node quadrilateral plane finite element is developed based on a novel unsymmetric formulation which is characterized by the use of two sets of shape functions, viz., the compatibility enforcing shape functions and completeness enforcing shape functions. The former are chosen to satisfy exactly the minimum inter‐ as well as intra‐element displacement continuity requirements, while the latter are chosen to satisfy all the (linear and higher order) completeness requirements so as to reproduce exactly a quadratic displacement field. Numerical results from test problems reveal that the new element is indeed capable of reproducing exactly a complete quadratic displacement field under all types of admissible mesh distortions. In this respect, the proposed 8‐node unsymmetric element emerges to be better than the existing symmetric QUAD8, QUAD8/9, QUAD9, QUAD12 and QUAD16 elements, and matches the performance of the quartic element, QUAD25. For test problems involving a cubic or higher order displacement field, the proposed element yields a solution accuracy that is comparable to or better than that of QUAD8, QUAD8/9 and QUAD9 elements. Furthermore, the element maintains a good accuracy even with the reduced 2× 2 numerical integration. Copyright © 2003 John Wiley & Sons, Ltd.