bluuebunny/crossref_metadata_2025_split huggingface dataset:
Determination of spin compartment in arterial spin labeling MRI
Authors: Liu Peiying , Uh Jinsoo , Lu Hanzhang 
Published: August 2010

AbstractA major difference between arterial‐spin‐labeling MRI and gold‐standard radiotracer blood flow methods is that the compartment localization of the labeled spins in the arterial‐spin‐labeling image is often ambiguous, which may affect the quantification of cerebral blood flow. In this study, we aim to probe whether the spins are located in the vascular system or tissue by using T2 of the arterial‐spin‐labeling signal as a marker. We combined two recently developed techniques, pseudo‐continuous arterial spin labeling and T2‐Relaxation‐Under‐Spin‐Tagging, to determine the T2 of the labeled spins at multiple postlabeling delay times. Our data suggest that the labeled spins first showed the T2 of arterial blood followed by gradually approaching and stabilizing at the tissue T2. The T2 values did not decrease further toward the venous T2. By fitting the experimental data to a two‐compartment model, we estimated gray matter cerebral blood flow, arterial transit time, and tissue transit time to be 74.0 ± 10.7 mL/100g/min (mean ± SD, N = 10), 938 ± 156 msec, and 1901 ± 181 msec, respectively. The arterial blood volume was calculated to be 1.18 ± 0.21 mL/100 g. A postlabeling delay time of 2 s is sufficient to allow the spins to completely enter the tissue space for gray matter but not for white matter. Magn Reson Med, 2010. © 2010 Wiley‐Liss, Inc.
Novel spherical phantoms for Q‐ball imaging under in vivo conditions
Authors: Moussavi‐Biugui Amir , Stieltjes Bram , Fritzsche Klaus , Semmler Wolfhard , Laun Frederik B. 
Published: August 2010

AbstractFor the validation of complex diffusion imaging techniques like q‐ball imaging that aim to resolve multiple fiber directions, appropriate phantoms are highly desirable. However, previous q‐ball imaging phantoms had diffusion anisotropies well below those of in vivo white matter. In this work, fiber phantoms of well‐defined geometry are presented. The fibers are wound on a spherical spindle yielding high packing densities and consequently high diffusion anisotropies (fractional anisotropy 0.93 ± 0.02 at b = 500 s/mm2). Phantoms with 90° and 45° crossing angle were constructed both with two crossing types. In the “stacked” crossing, two fiber strings were wound consecutively to simulate two touching fibers, in the “interleaved” crossing, fibers were wound alternately. The stacked crossing allows the alteration of partial volumes, whereas the interleaved crossing provides constant partial volumes, allowing e.g. the easy alteration of the SNR by varying the slice thickness. Exemplary q‐ball imaging validation measurements using different b‐values and slice thicknesses are presented. Magn Reson Med, 2010. © 2010 Wiley‐Liss, Inc.
Accelerated cardiac magnetic resonance imaging in the mouse using an eight‐channel array at 9.4 Tesla
Authors: Schneider Jürgen E. , Lanz Titus , Barnes Hannah , Stork Lee‐Anne , Bohl Steffen , Lygate Craig A. , Ordidge Roger J. , Neubauer Stefan 
Published: August 2010

AbstractMRI has become an important tool to noninvasively assess global and regional cardiac function, infarct size, or myocardial blood flow in surgically or genetically modified mouse models of human heart disease. Constraints on scan time due to sensitivity to general anesthesia in hemodynamically compromised mice frequently limit the number of parameters available in one imaging session. Parallel imaging techniques to reduce acquisition times require coil arrays, which are technically challenging to design at ultrahigh magnetic field strengths. This work validates the use of an eight‐channel volume phased‐array coil for cardiac MRI in mice at 9.4 T. Two‐ and three‐dimensional sequences were combined with parallel imaging techniques and used to quantify global cardiac function, T1‐relaxation times and infarct sizes. Furthermore, the rapid acquisition of functional cine‐data allowed for the first time in mice measurement of left‐ventricular peak filling and ejection rates under intravenous infusion of dobutamine. The results demonstrate that a threefold accelerated data acquisition is generally feasible without compromising the accuracy of the results. This strategy may eventually pave the way for routine, multiparametric phenotyping of mouse hearts in vivo within one imaging session of tolerable duration. Magn Reson Med, 2010. © 2010 Wiley‐Liss, Inc.
Effect of shoulder angle on the activation pattern of the elbow extensors during a submaximal isometric fatiguing contraction
Authors: Davidson Andrew W. , Rice Charles L. 
Published: August 2010

AbstractThe aim of this study was to examine the effect of shoulder angle on the electromyographic (EMG) activation pattern of the elbow extensors during a fatiguing contraction. Ten young men (23.5 ± 1.7) were tested on two occasions with the elbow angle at 90° and the shoulder at either 0° or 90° of flexion. EMG was recorded by fine wire electrodes inserted into the lateral, medial, and long heads of the triceps brachii and the anconeus. An EMG‐torque relationship was determined prior to a sustained isometric contraction at 20% of maximum voluntary contraction (MVC) until target failure. Endurance time was shorter, and postfatigue MVC torque was lower at 90° (40.4 ± 12.7 Nm) versus 0° (47.9 ± 14.7 Nm) of flexion. EMG activity of the long head during the final 10% of the fatiguing contraction was significantly greater at 90° versus 0° with no effect of shoulder angle on any other muscle portions. The findings suggest that measures from one muscle portion of the elbow extensors are not representative of the whole group, and the relative activation of the two‐joint long head was changed depending on shoulder angle during a fatigue task. Muscle Nerve, 2010
Permissive environment for B‐cell maturation in myositis muscle in the absence of B‐cell follicles
Authors: Salajegheh Mohammad , Pinkus Jack L. , Amato Anthony A. , Morehouse Chris , Jallal Bahija , Yao Yihong , Greenberg Steven A. 
Published: August 2010

AbstractMyositis muscle contains antigen‐matured B‐cells and plasma cells. Myositis muscle biopsy specimens were examined for nodular collections of T‐cells, B‐cells, myeloid dendritic cells, plasma cells, and follicular dendritic cells. Immunoglobulin and B‐cell–activating factor (BAFF) transcripts were quantitated. Laser‐capture microdissection was used to isolate single plasma cells, and their immunoglobulin transcripts were sequenced. Dense inflammatory infiltrates contained histological elements of ectopic lymphoid tissue but not B‐cell follicles. Immunoglobulin transcript sequence analysis demonstrated spatially distributed, clonally related B‐cells and plasma cells, suggesting local maturation of B‐cells into plasma cells in myositis muscle. Regions of dense cellular infiltrates in myositis muscle are sometimes areas of B‐cell maturation into antibody‐producing plasma cells. An atypical lymphoid histology, lacking concentrated collections of germinal‐center–like B‐cell follicles, is capable of antigen‐stimulated clonal maturation of antibody‐producing plasma cells. Muscle Nerve, 2010
Natural history of exertional rhabdomyolysis: A population‐based analysis
Authors: Alpers Joshua P. , Jones Lyell K. 
Published: September 2010

AbstractExertional rhabdomyolysis is a potentially catastrophic syndrome with an incidence and rate of recurrence that are unknown. In this study patients with rhabdomyolysis were identified retrospectively from the Wilford Hall Medical Center records. A population‐based analysis was performed on exertional rhabdomyolysis patients enrolled in basic military training. A retrospective cohort was analyzed for rate and risks of recurrence. Of 177 rhabdomyolysis patients, 63 were exertional in mechanism. The rate of renal failure was lower in exertional rhabdomyolysis patients (odds ratio 0.45, 95% confidence interval 0.22–0.95, P = 0.04). There were 44 cases of exertional rhabdomyolysis from a population of 198,399 total military trainees over the study period, or 22.2 cases per 100,000 per year. A cohort of 22 exertional rhabdomyolysis patients was followed for a mean of 31.2 months, with only 1 recurrence (recurrence risk of 0.08% per person per year). Exertional rhabdomyolysis is associated with lower rates of complications than other causes of rhabdomyolysis. Among young, physically active patients, the incidence of exertional rhabdomyolysis is low, as is the risk of recurrence. Muscle Nerve, 2010
Probabilistic muscle characterization using quantitative electromyography: Application to facioscapulohumeral muscular dystrophy
Authors: Pino Lou Joseph , Stashuk Daniel W. , Podnar Simon 
Published: August 2010

AbstractBased on quantitative electromyography, a muscle can be categorized as normal or affected by a neuromuscular disorder. The objective of this work was to compare the utility of probabilistic to conventional means and outlier methods of categorization of myopathic and normal muscles. Various sets of motor unit potential (MUP) features detected in biceps brachii muscles of control subjects and patients with facioscapulohumeral muscular dystrophy were used to categorize them as normal or myopathic based on conventional means and outlier categorization (CMC) as well as a new probabilistic muscle categorization (PMC). The sensitivity, specificity, and accuracy provided by each categorization method were compared. The categorizations made using PMC were significantly more accurate (by at least 10%) compared with CMC (P < 10−10) for muscles evaluated in this study. Area, duration, and thickness were highly discriminative MUP features. Muscle Nerve, 2010
A novel SOD1 mutation in a young amyotrophic lateral sclerosis patient with a very slowly progressive clinical course
Authors: Georgoulopoulou Eleni , Gellera Cinzia , Bragato Cinzia , Sola Patrizia , Chiari Annalisa , Bernabei Chiara , Mandrioli Jessica 
Published: August 2010

AbstractApproximately 10% of amyotrophic lateral sclerosis (ALS) cases are familial, and the Cu/Zn superoxide dismutase (SOD1) gene mutation accounts for 20% of them. More than 100 SOD1 mutations have been described, some with peculiar phenotypes. Moreover, mutations in the SOD1 gene have been described in apparently sporadic ALS cases. We report a new mutation (D11Y) in the Cu/Zn superoxide dismutase gene in a patient with ALS and an unusually slow disease progression. Muscle Nerve, 2010
Compound muscle action potential and motor function in children with spinal muscular atrophy
Authors: Lewelt Aga , Krosschell Kristin J. , Scott Charles , Sakonju Ai , Kissel John T. , Crawford Thomas O. , Acsadi Gyula , D'anjou Guy , Elsheikh Bakri , Reyna Sandra P. , Schroth Mary K. , Maczulski Jo Anne , Stoddard Gregory J. , Elovic Elie , Swoboda Kathryn J. 
Published: August 2010

AbstractReliable outcome measures that reflect the underlying disease process and correlate with motor function in children with SMA are needed for clinical trials. Maximum ulnar compound muscle action potential (CMAP) data were collected at two visits over a 4–6‐week period in children with SMA types II and III, 2–17 years of age, at four academic centers. Primary functional outcome measures included the Modified Hammersmith Functional Motor Scale (MHFMS) and MHFMS‐Extend. CMAP negative peak amplitude and area showed excellent discrimination between the ambulatory and non‐ambulatory SMA cohorts (ROC = 0.88). CMAP had excellent test–retest reliability (ICC = 0.96–0.97, n = 64) and moderate to strong correlation with the MHFMS and MHFMS‐Extend (r = 0.61–0.73, n = 68, P < 0.001). Maximum ulnar CMAP amplitude and area is a feasible, valid, and reliable outcome measure for use in pediatric multicenter clinical trials in SMA. CMAP correlates well with motor function and has potential value as a relevant surrogate for disease status. Muscle Nerve, 2010
Three‐dimensional inverse analyses of a deep excavation in Chicago clays
Authors: Hashash Youssef M. A. , Song Hwayeon , Osouli Abdolreza 
Published: August 2010

AbstractNumerical models are commonly used to estimate excavation‐induced ground movements. Two‐dimensional (2D) plain strain assumption is typically used for the simulation of deep excavations which might not be suitable for excavations where three‐dimensional (3D) effects dominate the ground response. This paper adapts an inverse analysis algorithm to learn soil behavior from field measurements using a 3D model representation of an excavation. The paper describes numerical issues related to this development including the generation of the 3D model mesh from laser scan images of the excavation. The inverse analysis to extract the soil behavior in 3D is presented. The model captures the measured wall deflections. Although settlements were not sufficiently measured, the predicted settlements around the excavation site reflected strong 3D effects and were consistent with empirical correlations. Copyright © 2010 John Wiley & Sons, Ltd.
Modeling of dynamic cohesive fracture propagation in porous saturated media
Authors: Khoei A. R. , Barani O. R. , Mofid M. 
Published: August 2010

AbstractIn this paper, a mathematical model is presented for the analysis of dynamic fracture propagation in the saturated porous media. The solid behavior incorporates a discrete cohesive fracture model, coupled with the flow in porous media through the fracture network. The double‐nodded zero‐thickness cohesive interface element is employed for the mixed mode fracture behavior in tension and contact behavior in compression. The crack is automatically detected and propagated perpendicular to the maximum effective stress. The spatial discretization is continuously updated during the crack propagation. Numerical examples from the hydraulic fracturing test and the concrete gravity dam show the capability of the model to simulate dynamic fracture propagation. The comparison is performed between the quasi‐static and fully dynamic solutions, and the performance of two analyses is investigated on the values of crack length and crack mouth opening. Copyright © 2010 John Wiley & Sons, Ltd.
Prediction of blast fragmentation using multivariate analysis procedures
Authors: Hudaverdi T. , Kulatilake P. H. S. W. , Kuzu C. 
Published: August 2010

AbstractAn extensive multivariate analysis procedure for prediction of blast fragmentation distribution is presented. Several blasts performed in various mines and rock formations in the world are brought together and evaluated. Blast design parameters, the modulus of elasticity, in situ block size are considered to perform multivariate analysis. The hierarchical cluster analysis is used to separate the blasts data into different groups of similarity. Group memberships were checked by the discriminant analysis. The multivariate regression analysis was applied to develop prediction equations for the estimation of the mean particle size of muckpiles. Two different prediction equations were developed based on the rock stiffness. Validation of the proposed equations on various mines is presented and the capability of the prediction equations was compared with one of the most applied fragmentation distribution models appearing in the blasting literature. Prediction capability of the proposed models was found to be strong. Diversity of the blasts data used is one of the most important aspects of the developed models. The models are not complex and suitable for practical use at mines. Copyright © 2010 John Wiley & Sons, Ltd.
Degradation of rock fracture asperities in unloading, reloading, and reversal
Authors: Asadollahi Pooyan , Tonon Fulvio 
Published: August 2010

AbstractAmong the constitutive models for rock fractures developed over the years, Barton's empirical model has been widely used. Although Barton's failure criterion predicts peak shear strength of rock fractures with acceptable precision, it has some limitations in estimating the peak shear displacement, post‐peak shear strength, dilation, and surface degradation. The first author modified Barton's original model in order to address these limitations.Barton proposed his model for degradation of fracture asperities in unloading, reloading, and shear displacement reversal based on just one cyclic direct shear test. In this study, a database of results of 18 cyclic direct shear tests available in the literature was collected and analyzed. Modifications were made to Barton's original model (in terms of fracture cyclic shearing) to make it consistent with the modified model proposed by the first author. Copyright © 2010 John Wiley & Sons, Ltd.
Isogeometric finite element data structures based on Bézier extraction of NURBS
Authors: Borden Michael J. , Scott Michael A. , Evans John A. , Hughes Thomas J. R. 
Published: August 2010

AbstractWe present the B'ezier extraction operator and isogeometric Bézier elements for non‐uniform rational B‐Spline (NURBS)‐based isogeometric analysis. The Bézier extraction operator allows numerical integration of smooth functions to be performed on C0 Bézier elements. We show how the Bézier extraction operator is computed for NURBS. We then show that the extraction operator and Bézier elements provide an element structure for isogeometric analysis that can be easily incorporated into existing finite element codes, without any changes to element form and assembly algorithms, and standard data processing arrays. All significant changes may be implemented in a shape function subroutine. Copyright © 2010 John Wiley & Sons, Ltd.
A system‐level model reduction technique for the efficient simulation of flexible multibody systems
Authors: Heirman Gert H. K. , Naets Frank , Desmet Wim 
Published: August 2010

AbstractFlexible multibody systems are governed by sets of non‐linear differential‐algebraic equations (DAE). The number of degrees of freedom (DOFs) required for accurate body flexibility modeling, as well as the presence of the algebraic constraint equations limit the simulation speed. Body‐level model reduction and general‐purpose system‐level model reduction techniques do not result in optimal model dimension reduction and do not necessarily transform the DAE‐set into a cheaper to solve set of ordinary differential equations, as opposed to model reduction techniques, such as Global Modal Parameterization (GMP), which are based on describing the system motion by the contribution of its dominant (configuration‐dependent) system‐level modal patterns. Their use as a simulation tool has not been thoroughly investigated. This paper investigates the influence of the modal content of the configuration‐dependent mode set on the simulation accuracy through numerical experiments. By including the dynamically excited eigenmodes and static deformation patterns for DOFs in which the system is externally loaded, the system can be accurately represented by a very limited number of DOFs. Phenomena such as mode veering and mode crossing, in which the modal content of eigenmodes rapidly varies, can be expected to be problematic for such a description, which is confirmed with numerical experiments. Copyright © 2010 John Wiley & Sons, Ltd.
An efficient framework for fluid–structure interaction using the lattice Boltzmann method and immersed moving boundaries
Authors: Owen D. R. J. , Leonardi C. R. , Feng Y. T. 
Published: August 2010

AbstractThis paper presents a serial computational framework that hydrodynamically couples the lattice Boltzmann method (LBM) and the discrete element method (DEM) for the solution of particle suspension problems in two and three dimensions. The single‐relaxation‐time Bhatnagar–Gross–Krook (LBGK) form of the lattice Boltzmann equation is employed with an immersed moving boundary method for the fluid–structure interaction. Similar algorithms have been previously reported in the literature, however, this work deliberately utilizes solution options that minimize the computational overheads of the framework to facilitate simulations of multibody structural fields in large fluid domains. In particular, mixed boundary conditions are employed which combine the simple bounce‐back technique with the immersed moving boundary method, and the relatively inexpensive D3Q15 lattice is employed for 3D solutions. The fundamentals of the LBM are briefly discussed followed by a review of the coupling techniques available for FSI using the LBM. Options for mapping solid obstacles to the LBM grid are presented and an algorithm for automatic, dynamic subcycling of the two explicit solution schemes is outlined. The LBM–DEM framework is then validated and benchmarked against previously published LBM results, with comments made where appropriate on the comparative accuracy and convergence characteristics. Finally, a multi‐particle suspension simulation is presented to qualitatively assess the performance of the framework when a large number of dynamic contacts exist. Copyright © 2010 John Wiley & Sons, Ltd.
A thin plate formulation without rotation DOFs based on the radial point interpolation method and triangular cells
Authors: Cui X. Y. , Liu G. R. , Li G. Y. , Zhang G. Y. 
Published: August 2010

AbstractA formulation for thin plates with only the deflection as nodal variables has been proposed using the generalized gradient smoothing technique and the radial point interpolation method (RPIM). The deflection fields are approximated using the RPIM shape functions which possess the Kronecker Delta property for easy impositions of essential boundary conditions. Three types of smoothing domains, which are also serving as the numerical integrations domains, are constructed based on the background three‐node triangular cells and the generalized gradient smoothing operation is performed over each of them to obtain the smoothed curvatures. The generalized smoothed Galerkin weak form is then used to create the discretized system equations. The essential boundary conditions of rotations are imposed in the process of constructing the curvature field, and the translation boundary conditions are imposed as in the standard FEM. A number of numerical examples, including both static and free vibration analysis, are studied using the present methods and the numerical results are compared with the analytical ones and those in the open literatures. The results show that the present formulation can obtain very stable and accurate solutions, even for the extremely irregular background cells. Copyright © 2010 John Wiley & Sons, Ltd.