bluuebunny/crossref_metadata_2025_split huggingface dataset:
Frequency‐volume charts: A tool to evaluate bladder sensation
Authors: Wachter Stefan De , Wyndaele Jean‐Jacques 
Published: October 2003

AbstractAimsBladder sensation is routinely evaluated by cystometric bladder filling and electrical stimulation. These methods require catheterization and stimulate the bladder artificially. In this study, we evaluated whether frequency‐volume charts can be used as a non‐invasive tool to study bladder sensation during normal daily life. Furthermore the agreement between sensory data obtained from frequency‐volume charts and conventional cystometric bladder filling is studied.Materials and MethodsFifteen healthy female students filled out frequency‐volume charts at home and scored the grade of perception of bladder fullness at each micturition. They also measured the volume of three voidings after postponing micturition as long as possible. Sensation of bladder filling was finally evaluated during cystometry.ResultsOn frequency‐volume charts, 65% of all voidings was made without desire to void, only 9.5% was with strong desire. Urgent desire to void was not reported except after voluntarily postponing micturition. Higher grades of perception of fullness were associated with significantly higher voided volumes. Mean volumes for the different sensations of fullness on the charts were not significantly different from volumes at different sensations reported during cystometry.ConclusionsIn conclusion, bladder sensation during daily life can be evaluated by scoring the grade of perception of fullness on frequency‐volume charts. During life voiding usually occurs without desire to void. The voided volumes at different sensations of fullness are comparable to the volumes at different sensations of filling during cystometry. Therefore, frequency‐volume charts with evaluation of perception of fullness may provide an initial non‐invasive tool to study bladder sensation. Neurourol. Urodynam. 22:638–642, 2003. © 2003 Wiley‐Liss, Inc.
Functions of intermediate filaments in neuronal development and disease
Authors: Lariviere Roxanne C. , Julien Jean‐Pierre 
Published: October 2003

AbstractFive major types of intermediate filament (IF) proteins are expressed in mature neurons: the three neurofilament proteins (NF‐L, NF‐M, and NF‐H), α‐internexin, and peripherin. While the differential expression of IF genes during embryonic development suggests potential functions of these proteins in axogenesis, none of the IF gene knockout experiments in mice caused gross developmental defects of the nervous system. Yet, deficiencies in neuronal IF proteins are not completely innocuous. Substantial developmental loss of motor axons was detected in mice lacking NF‐L and in double knockout NF‐M;NF‐H mice, supporting the view of a role for IFs in axon stabilization. Moreover, the absence of peripherin resulted in ≈30% loss of small sensory axons. Mice lacking NF‐L had a scarcity of IF structures and exhibited a severe axonal hypotrophy, causing up to 50% reduction in conduction velocity, a feature that would be very detrimental for large animal species. Unexpectedly, the NF‐M rather than NF‐H protein turned out to be required for proper radial growth of large myelinated axons. Studies with transgenic mice suggest that some types of IF accumulations, reminiscent of those found in amyotrophic lateral sclerosis (ALS), can have deleterious effects and even cause neurodegeneration. Additional evidence for the involvement of IFs in pathogenesis came from the recent discovery of neurofilament gene mutations linked to ALS and Charcot‐Marie‐Tooth disease (CMT2E). Conversely, we discuss how certain types of perikaryal neurofilament aggregates might confer protection in motor neuron disease. © 2003 Wiley Periodicals, Inc. J Neurobiol 58: 131–148, 2004
How actin filaments and microtubules steer growth cones to their targets
Authors: Zhou Feng‐Quan , Cohan Christopher S. 
Published: October 2003

AbstractGuidance molecules steer growth cones to their targets by attracting or repelling them. Turning in a new direction requires remodeling of the growth cone and bending of the axon. This depends upon reorganization of actin filaments and microtubules, which are the primary cytoskeletal components of growth cones. This article discusses how these cytoskeletal components induce turning. The importance of each component as well as how interactions between them result in axon guidance is discussed. Current evidence shows that microtubules are influenced by both the organization and dynamics of actin filaments in the peripheral domain of growth cones. Cytoskeletal models for repulsive and attractive turning are presented. Molecular candidates that may link actin filaments with microtubules are suggested and potential signal transduction pathways that allow these cytoskeletal components to affect each other are discussed. © 2003 Wiley Periodicals, Inc. J Neurobiol 58: 84–91, 2004
Cytoskeletal‐associated proteins in the migration of cortical neurons
Authors: Bielas Stephanie L. , Gleeson Joseph G. 
Published: October 2003

AbstractNeuronal migration is a hallmark of cerebral cortical development as neurons born deep within the brain migrate to the surface in a highly choreographed process. The cytoskeleton extends throughout the cell, mediating the dramatic morphological changes that accompany migration. On a cellular level, proper migration is accompanied by polarization of the cytoskeleton and cellular contents and by dynamic reorganization that generates the force for cell locomotion. Genetic analyses of human brain malformations, as well as genetically engineered mouse mutants, have highlighted a number of cytoskeletal‐associated proteins underlying these functions, which are necessary for proper cortical development. While these proteins are involved in diverse molecular mechanisms, disruption during development results in the ectopic placement of neurons in the cortex. We review key cytoskeletal events and the critical cytoskeletal‐associated proteins involved in cortical neuronal migration. © 2003 Wiley Periodicals, Inc. J Neurobiol 58: 149–159, 2004
Regulation of growth cone actin filaments by guidance cues
Authors: Gallo Gianluca , Letourneau Paul C. 
Published: October 2003

AbstractThe motile behaviors of growth cones at the ends of elongating axons determine pathways of axonal connections in developing nervous systems. Growth cones express receptors for molecular guidance cues in the local environment, and receptor‐guidance cue binding initiates cytoplasmic signaling that regulates the cytoskeleton to control growth cone advance, turning, and branching behaviors. The dynamic actin filaments of growth cones are frequently targets of this regulatory signaling. Rho GTPases are key mediators of signaling by guidance cues, although much remains to be learned about how growth cone responses are orchestrated by Rho GTPase signaling to change the dynamics of polymerization, transport, and disassembly of actin filaments. Binding of neurotrophins to Trk and p75 receptors on growth cones triggers changes in actin filament dynamics to regulate several aspects of growth cone behaviors. Activation of Trk receptors mediates local accumulation of actin filaments, while neurotrophin binding to p75 triggers local decrease in RhoA signaling that promotes lengthening of filopodia. Semaphorin IIIA and ephrin‐A2 are guidance cues that trigger avoidance or repulsion of certain growth cones, and in vitro responses to these proteins include growth cone collapse. Dynamic changes in the activities of Rho GTPases appear to mediate responses to these cues, although it remains unclear what the changes are in actin filament distribution and dynamic reorganization that result in growth cone collapse. Growth cones in vivo simultaneously encounter positive and negative guidance cues, and thus, growth cone behaviors during axonal pathfinding reflect the complex integration of multiple signaling activities. © 2003 Wiley Periodicals, Inc. J Neurobiol 58: 92–102, 2004
Actin and microtubules in neurite initiation: Are MAPs the missing link?
Authors: Dehmelt Leif , Halpain Shelley 
Published: October 2003

AbstractDuring neurite initiation microtubules align to form a tight bundle and actin filaments reorganize to produce a growth cone. The mechanisms that underlie these highly coordinated cytoskeletal rearrangements are not yet fully understood. Recently, various levels of coordination between the actin‐ and microtubule‐based cytoskeletons have been observed during cellular migration and morphogenesis, processes that share some similarities to neurite initiation. Direct, physical association between both cytoskeletons has been suggested, because microtubules often preferentially grow along actin bundles and transiently target actin‐rich adhesion complexes. We propose that such physical association might be involved in force‐based interactions and spatial organization of the two networks during neurite initiation as well. In addition, many signaling cascades that affect actin filaments are also involved in the regulation of microtubule dynamics, and vice versa. Although several candidates for mediating these effects have been identified in non‐neuronal cells, the general mechanism is still poorly understood. In neurons certain plakins and neuron‐specific microtubule associated proteins (MAPs), like MAP1B and MAP2, which can bind to both microtubules and F‐actin, are promising candidates to play key roles in the specific cytoskeletal rearrangements controlling the transition from an undifferentiated state to neurite‐bearing morphology. Here we review the effects of MAPs on microtubules and actin, as well as the coordination of both cytoskeletons during neurite initiation. © 2003 Wiley Periodicals, Inc. J Neurobiol 58: 18–33, 2004
Myosin function in nervous and sensory systems
Authors: Brown Michael E. , Bridgman Paul C. 
Published: October 2003

AbstractDevelopment of the nervous system requires remarkable changes in cell structure that are dependent upon the cytoskeleton. The importance of specific components of the neuronal cytoskeleton, such as microtubules and neurofilaments, to neuronal function and development has been well established. Recently, increasing focus has been put on understanding the functional role of the actin cytoskeleton in neurons. Important modulators of the actin cytoskeleton are the large family of myosins, many of which (classes I, II, III, V, VI, VII, IX, and XV; Fig. 1) are expressed in developing neurons or sensory cells. Myosins are force‐producing proteins that have been implicated in a wide variety of cellular functions in the developing nervous system, including neuronal migration, process outgrowth, and growth cone motility, as well as other aspects of morphogenesis, axonal transport, and synaptic and sensory functions. We review the roles that neuronal myosins play in these functions with particular focus on the first three events listed above, as well as sensory function. © 2003 Wiley Periodicals, Inc. J Neurobiol 58: 118–130, 2004
Efficient preconditioners for boundary element matrices based on grey‐box algebraic multigrid methods
Authors: Langer U. , Pusch D. , Reitzinger S. 
Published: October 2003

AbstractThis paper is concerned with the iterative solution of the boundary element equations arising from standard Galerkin boundary element discretizations of first‐kind boundary integral operators of positive and negative order. We construct efficient preconditioners on the basis of so‐called grey‐box algebraic multigrid methods that are well adapted to the treatment of boundary element matrices. In particular, the coarsening is based on an auxiliary matrix that represents the underlying topology in a certain sense. This auxiliary matrix is additionally used for the construction of the smoothers and the transfer operators. Finally, we present the results of some numerical studies that show the efficiency of the proposed algebraic multigrid preconditioners. Copyright © 2003 John Wiley & Sons, Ltd.
A polynomial collocation method for the numerical solution of weakly singular and singular integral equations on non‐smooth boundaries
Authors: Monegato G. , Scuderi L. 
Published: October 2003

AbstractThe aim of this paper is to show the efficiency of the use of smoothing changes of variable in the numerical treatment of 1D and 2D weakly singular and singular integral equations. The introduction of a smoothing transformation, besides smoothing the solution, allows also the use of a very simple and efficient collocation method based on Chebyshev polynomials of the first kind and their zeros. Further, we propose proper smoothing changes of variable also for the numerical approximation of those collocation matrix elements, which are given by weakly singular, singular or nearly singular integrals. Several numerical tests are given to point out the efficiency of the numerical approach we propose. Copyright © 2003 John Wiley & Sons, Ltd.
A solid‐like shell element allowing for arbitrary delaminations
Authors: Remmers Joris J. C. , Wells Garth N. , Borst René de 
Published: October 2003

AbstractIn this contribution a new finite element is presented for the simulation of delamination growth in thin‐layered composite structures. The element is based on a solid‐like shell element: a volume element that can be used for very thin applications due to a higher‐order displacement field in the thickness direction. The delamination crack can occur at arbitrary locations and is incorporated in the element as a jump in the displacement field by using the partition of unity property of finite element shape functions. The kinematics of the element as well as the finite element formulation are described. The performance of the element is demonstrated by means of two examples. Copyright © 2003 John Wiley & Sons, Ltd.
An enriched finite element method and level sets for axisymmetric two‐phase flow with surface tension
Authors: Chessa Jack , Belytschko Ted 
Published: October 2003

AbstractA finite element method for axisymmetric two‐phase flow problems is presented. The method uses an enriched finite element formulation, in which the interface can move arbitrarily through the mesh without remeshing. The enrichment is implemented by the extended finite element method (X‐FEM) which models the discontinuity in the velocity gradient at the interface by a local partition of unity. It provides an accurate representation of the velocity field at interfaces on an Eulerian grid that is not conformal to the weak discontinuity. The interface is represented by a level set which is also used in the construction of the element enrichment. Surface tension effects are considered and the interface curvature is computed from the level set field. The method is demonstrated by several examples. Copyright © 2003 John Wiley & Sons, Ltd.
Analysis of a subdomain‐based error estimator for finite element approximations of elliptic problems
Authors: Prudhomme S. , Nobile F. , Chamoin L. , Oden J. T. 
Published: October 2003

AbstractIn this article we analyze a subdomain residual error estimator for finite element approximations of elliptic problems. It is obtained by solving local problems on patches of elements in weighted spaces and provides an upper bound on the energy norm of the error when the local problems are solved in sufficiently enriched discrete spaces. A guaranteed lower bound on the error is also derived by a simple postprocess of the solutions to the local problems. Numerical tests show very good effectivity indices for both the upper and lower bounds and a strong reliability of this estimator even for coarse meshes. © 2003 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq 20: 165–192, 2004
Approximation of time‐dependent, viscoelastic fluid flow: Crank‐Nicolson, finite element approximation
Authors: Ervin Vincent J. , Heuer Norbert 
Published: October 2003

AbstractIn this article we analyze a fully discrete approximation to the time dependent viscoelasticity equations with an Oldroyd B constitutive equation in ℝ$^{\acute{d}}$, $\acute{d}$ = 2, 3. We use a Crank‐Nicolson discretization for the time derivatives. At each time level a linear system of equations is solved. To resolve the nonlinearities we use a three‐step extrapolation for the prediction of the velocity and stress at the new time level. The approximation is stabilized by using a discontinuous Galerkin approximation for the constitutive equation. For the mesh parameter, h, and the temporal step size, Δt, sufficiently small and satisfying Δt ≤ Ch$^{\acute{d}/4}$, existence of the approximate solution is proven. A priori error estimates for the approximation in terms of Δt and h are also derived. © 2003 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq 20: 248–283, 2004
Wavelets‐Galerkin scheme for a Stokes problem
Authors: Zhou Xiaolin 
Published: October 2003

AbstractThis note presents a wavelets‐Galerkin scheme for the numerical solution of a Stokes problem by using the scaling function of a symmetric biorthogonal spline wavelets that can be modified to generate the divergence‐free wavelets. © 2003 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq 20: 193–198, 2004
A second‐order linearized difference scheme on nonuniform meshes for nonlinear parabolic systems with Neumann boundary value conditions
Authors: Zhang Ling‐yun , Sun Zhi‐zhong 
Published: October 2003

AbstractA linearized three‐level difference scheme on nonuniform meshes is derived by the method of the reduction of order for the Neumann boundary value problem of a nonlinear parabolic system. It is proved that the difference scheme is uniquely solvable and second‐order convergent in L∞‐norm. A numerical example is given. © 2003 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq 20: 230–247, 2004
Synthesis and characterization of guar gum‐graft‐polyacrylonitrile
Authors: Thimma Reddy T. , Reddy N. Subbarami , Tammishetti Shekharam 
Published: October 2003

AbstractCerium(IV) mediated grafting of polyacrylonitrile on to guar gum was studied. Grafting parameters were studied gravimetrically, as a function of temperature, initiator concentration and Guar to acrylonitrile ratio. Higher temperatures resulted in higher monomer conversion and homopolymer formation. Both monomer conversion and extent of grafting increased with increase in cerium ion concentration in the range studied (0.91–9.12 mmol/l). Similar results were obtained with increase in monomer to guar gum ratio from 1 to 5. Grafting with this initiator was found to be generally good with high grafting efficiencies and low homopolymer formation for most experiments. The copolymers obtained were subjected to alkaline hydrolysis to convert nitrile groups in to carboxylic acid groups and the water absorbency of the resulting anionic guar gum was studied. Materials with water absorption up to 300 g/g could be obtained from this study. Copyright © 2003 John Wiley & Sons, Ltd.
Extrudate swell behavior of PS and LLDPE melts in a dual die with mixed circular/slit flow channels in an extrusion rheometer
Authors: Sombatsompop N. , O‐Charoen N. 
Published: October 2003

AbstractExtrudate swell behaviors of polystyrene (PS) and linear low‐density polyethylene (LLDPE) melts in a dual channel die, having mixed circular/slit flow channels, in a constant shear rate rheometer were examined. The extrudate swell ratio for PS melt was observed to be higher than that for LLDPE melt for all cases, this being associated with the differences in molecular structures that could be described in terms of power law indexes and secondary flows near the die entrance. In single channel die, the extrudate swell of both PS and LLDPE melts in circular flow channel die was greater than that in slit flow channel, whereas, in dual channel die the slit channel exhibited a higher extrudate swell ratio, the results being explained by revealing the flow patterns of the melt in the barrel and die of the rheometer. It was found that the dimensionless size of the vortex flows near the entrance, and the extent of disentanglement of molecular chains on entering the die were the important factors for the differences in the extrudate swell ratios of the melts at the die exit influenced by the die designs used. Copyright © 2003 John Wiley & Sons, Ltd.
Effect of proton irradiation on structure and optical property of PTFE film
Authors: Peng Guirong , Yang Dezhuang , He Shiyu 
Published: October 2003

AbstractEffects of protons on chemical structure and optical properties of polytetrafluoroethylene (PTFE) film were investigated in the energy range of 60 to 170 keV to simulate the effects of space proton irradiation environment. The results show that for PTFE film irradiated with protons, the change in C1s spectrum, along with those in F1s and the FT‐IR spectrum after irradiation, demonstrates that two processes take place simultaneously. One is substitution in which carbon to fluorine bonds can be broken by the protons and some positions of fluorine are occupied by active protons; the other is the carbonification, which results in the change of surface color and an increase of carbon percentage on the irradiated surface. For the PTFE film irradiated with 150 keV protons, the spectral absorbance ΔAλ in the wavelengths longer than 300 nm increase unmonotonously with proton fluence, and an abnormally recovery decrease of the ΔAλ with the increase of fluence in the range of 5×1013 cm−2 to 1015 cm−2 is observed. The change of the ΔAλ could be related to the competition of the carbonification and the substituting effect. The carbonification increases the ΔAλ, while the substituting increases the amorphousness amount, leading to an increase in the transparency of the film. In addition, the creation of radicals can also contribute to the increase in absorbance. Copyright © 2003 John Wiley & Sons, Ltd.
Enzyme degradability of benzylated sisal and its self‐reinforced composites
Authors: Lu Xun , Zhang Ming Qiu , Rong Min Zhi , Yang Gui Cheng 
Published: October 2003

AbstractTo produce natural polymer based composite materials, sisal fibers were slightly benzylated and then molded into sheets. Because the modified skin portions of the fibers acquired certain thermoplasticity and the unmodified core parts remain constant, the resultant composites fall into the category of self‐reinforced ones. The present article is devoted to the evaluation of the materials biodegradability with the help of cellulase. It was found that the inherent biodegradability of plant fibers is still associated with the benzylated sisal and the molded composites, as characterized by structural variation, weight loss and deterioration of mechanical performance of the materials. Reaction temperature and time, pH value of the enzyme solution, and dosage of the enzyme had significant influences on the decomposition behavior of the materials. In principle, the enzymolysis of sisal and its self‐reinforced composites is a diffusion‐controlled process. Due to the insusceptibility of lignin to cellulase and the hindrance of it to the cellulase solution, the degradation rates of the materials are gradually slowed down with an increase in time. Copyright © 2003 John Wiley & Sons, Ltd.