bluuebunny/crossref_metadata_2025 huggingface dataset:
Rapsyn mutations in myasthenic syndrome due to impaired receptor clustering
Authors: Maselli Ricardo A. , Dunne Vanessa , Pascual‐Pascual Samuel Ignacio , Bowe Constance , Agius Mark , Frank Rochelle , Wollmann Robert L.
Published: August 2003

Rapsyn, a 43‐kDa postsynaptic protein, is essential for anchoring and clustering acetylcholine receptors (AChRs) at the endplate (EP). Mutations in the rapsyn gene have been found to cause a postsynaptic congenital myasthenic syndrome (CMS). We detected six patients with CMS due to mutations in the rapsyn gene (RAPSN). In vitro studies performed in the anconeus muscle biopsies of four patients showed severe reduction of miniature EP potential amplitudes. Electron microscopy revealed various degrees of impaired development of postsynaptic membrane folds. All patients carried the N88K mutation. Three patients were homozygous for N88K and had less severe phenotypes and milder histopathologic abnormalities than the three patients who were heterozygous and carried a second mutation (either L14P, 46insC, or Y269X). Surprisingly, two N88K homozygous patients had one asymptomatic relative each who carried the same genotype, suggesting that additional genetic factors to RAPSN mutations are required for disease expression. Muscle Nerve 28: 293–301, 2003
Improvement of muscle healing through enhancement of muscle regeneration and prevention of fibrosis
Authors: Sato Kenji , Li Yong , Foster William , Fukushima Kazumasa , Badlani Neil , Adachi Nobuo , Usas Arvydas , Fu Freddie H. , Huard Johnny
Published: August 2003

Skeletal muscle is able to repair itself through regeneration. However, an injured muscle often does not fully recover its strength because complete muscle regeneration is hindered by the development of fibrosis. Biological approaches to improve muscle healing by enhancing muscle regeneration and reducing the formation of fibrosis are being investigated. Previously, we have determined that insulin‐like growth factor–1 (IGF‐1) can improve muscle regeneration in injured muscle. We also have investigated the use of an antifibrotic agent, decorin, to reduce muscle fibrosis following injury. The aim of this study was to combine these two therapeutic methods in an attempt to develop a new biological approach to promote efficient healing and recovery of strength after muscle injuries. Our findings indicate that further improvement in the healing of muscle lacerations is attained histologically by the combined administration of IGF‐1 to enhance muscle regeneration and decorin to reduce the formation of fibrosis. This improvement was not associated with improved responses to physiological testing, at least at the time‐points tested in this study. Muscle Nerve 28: 365–372, 2003
Spinal accessory neuropathy, droopy shoulder, and thoracic outlet syndrome
Authors: Al‐Shekhlee Amer , Katirji Bashar
Published: August 2003

Droopy shoulder has been proposed as a cause of thoracic outlet syndrome. Two patients developed manifestations of neurovascular compression upon arm abduction, associated with unilateral droopy shoulder and trapezius muscle weakness caused by iatrogenic spinal accessory neuropathies following cervical lymph node biopsies. The first patient developed a cold, numb hand with complete axillary artery occlusion when his arm was abducted to 90°. The second patient complained of paresthesias in digits 4 and 5 of the right hand, worsened by elevation of the arm, with nerve conduction findings of right lower trunk plexopathy (low ulnar and medial antebrachial cutaneous sensory nerve action potentials). Spinal accessory nerve grafting (in the first patient) coupled with shoulder strengthening physical exercises in both patients resulted in gradual improvement of symptoms in 2 years. These two cases demonstrate that unilateral droopy shoulder secondary to trapezius muscle weakness may cause compression of the thoracic outlet structures. Muscle Nerve 28: 383–385, 2003
Peripheral neuropathy in scleroderma
Authors: Poncelet Ann N. , Connolly M. Kari
Published: August 2003

Because patients with scleroderma report neuropathic symptoms including numbness, paresthesias, and dysesthesias, we assessed peripheral nerve function in such patients. Fourteen scleroderma patients underwent complete neurologic examination, nerve conduction studies (NCS) and quantitative sensory testing (QST). Neurologic examination revealed reduced vibration (7) or pinprick (4) sensation in the upper or lower extremities, focal atrophy or proximal weakness (2), and decreased deep tendon reflexes (2). NCS showed reduced sensory nerve action potentials (1) and carpal tunnel syndrome (1). QST of the upper and lower extremity revealed increased cold or vibration detection thresholds in 8 of 14 patients. Our findings suggest that peripheral neuropathy occurs in patients with scleroderma at a higher frequency than previously appreciated. These findings cannot be ascribed to compression neuropathies, but rather involve large and small fibers in a non–length‐dependent fashion. Larger, prospective studies using the more sensitive QST as well as pathologic studies of nerve, including cutaneous innervation, are needed to further assess the characteristics and etiology of the neuropathy. Muscle Nerve 28: 330–335, 2003
Clinical spectrum of muscle weakness in human West Nile virus infection
Authors: Leis A. Arturo , Stokic Dobrivoje S. , Webb Risa M. , Slavinski Sally A. , Fratkin Jonathan
Published: August 2003

Poliomyelitis has recently been identified as a cause of muscle weakness in patients with West Nile virus (WNV) infection. However, the clinical spectrum of WNV‐associated weakness has not been described. We reviewed data on 13 patients with WNV infection. Patients with muscle weakness were classified into one of three distinct groups based on clinical features. Group 1 comprised five patients who developed acute flaccid paralysis, four with meningoencephalitis and one without fever or other signs of infection. Paralysis was asymmetric, and involved from one to four limbs in individual patients. Electrodiagnostic studies confirmed involvement of anterior horn cells or motor axons. Group 2 involved two patients without meningoencephalitis who developed severe but reversible muscle weakness that recovered completely within weeks. Muscle weakness involved both lower limbs in one patient and one upper limb in the other. Group 3 consisted of two patients who experienced subjective weakness and disabling fatigue, but had no objective muscle weakness on examination. In addition to the three distinct groups, two other patients developed exaggerated weakness in the distribution of preexisting lower motor neuron dysfunction. We conclude that the clinical spectrum of WNV‐associated muscle weakness ranges from acute flaccid paralysis, with or without fever or meningoencephalitis, to disabling fatigue. Also, preexisting dysfunction may predispose anterior horn cells to additional injury from WNV. Awareness of this spectrum will help to avoid erroneous diagnoses and inappropriate treatment. Muscle Nerve 28: 302–308, 2003
Relative contributions of neural mechanisms versus muscle mechanics in promoting finger extension deficits following stroke
Authors: Kamper D.G. , Harvey R.L. , Suresh S. , Rymer W.Z.
Published: August 2003

The origins of impaired finger and hand function were examined in 10 stroke survivors with chronic spastic hemiparesis, with the intent of assessing whether mechanical restraint or altered neurophysiological control mechanisms are responsible for the well‐known impairment of finger extension. Simultaneous extension of all four metacarpophalangeal (MCP) joints of the impaired hand was either externally imposed using a rotary actuator or attempted voluntarily by the subject. Trials were conducted both before and after administration of a local anesthetic, blocking the median and ulnar nerves at the elbow. The anesthetic was administered to reduce the activity of the muscles flexing the MCP joints, in order to distinguish mechanical from neuronal resistance to imposed MCP rotation. We found that the nerve blockade resulted in a reduction in velocity‐dependent torque (P = 0.01), thereby indicating significant joint impedance due to spasticity. Blockade also produced a posture‐dependent reduction in static torque in declaratively relaxed subjects (P = 0.04), suggesting some tonic flexor activity for specific hand postures. No change in either extensor isometric (P = 0.33) or isokinetic (0.53) torque was apparent, but 3 of the 10 subjects did exhibit substantial (>10°) improvement in voluntary MCP extension following the blockade. This improvement seemed largely due to a decrease in inappropriate flexor activity during the movement, rather than an increase in extensor activity. We argue that persistent and inappropriate flexor activation plays a role in limiting voluntary finger extension, and that this activation is potentially a reflection of altered supraspinal control of key spinal pathways. In all cases, this inappropriate activation was compounded by weakness, apparent in both the extensor and flexor muscles. Muscle Nerve 28: 309–318, 2003
Caffeine impairs intramuscular energy balance in patients susceptible to malignant hyperthermia
Authors: Textor Zoran , Beer Meinrad , Anetseder Martin , Köstler Herbert , Kagerbauer Erwin , Kenn Werner , Hahn Dietbert , Roewer Norbert
Published: August 2003

Malignant hyperthermia (MH) is a metabolic myopathy with an abnormal release of calcium by the sarcoplasmic reticulum (SR), triggered by volatile anesthetics and succinylcholine. Similarly, caffeine enhances Ca2+release by the SR in vitro. In a prospective, randomized study, high‐energy phosphates were studied by intramuscular 31‐phosphorus magnetic resonance spectroscopy (31P‐MRS) in 10 MH‐susceptible (MHS) and 7 MH‐nonsusceptible (MHN) subjects before and after injection of 0.5 ml caffeine (20 mM). Intramuscular energy balance, measured by the ratios of Pi/PCr and Pi/γ‐ATP, did not differ between MHS and MHN patients before and after intramuscular caffeine injection. However, within each group, Pi/PCr and Pi/γ‐ATP increased significantly only in the MHS group. Intramuscular caffeine injection seemed to impair the metabolic balance in MHS individuals. This may reflect a local calcium overload leading to consumption of high‐energy phosphates and increase of inorganic phosphate. Intramuscular stimulation by caffeine and 31P‐MRS may provide a valuable tool to investigate MH‐related metabolic disturbances. Muscle Nerve 28: 353–358, 2003
Caffeine increases spinal excitability in humans
Authors: Walton C. , Kalmar J. , Cafarelli E.
Published: August 2003

The Hoffman reflex (H reflex) has long been established as a measure of spinal excitability. Caffeine is one of the most widely consumed drugs in the world. Because it is known to increase excitatory neurotransmission, we hypothesized that caffeine would increase spinal excitability and thus alter the H reflex by increasing its amplitude. Seven subjects each attended the laboratory on 2 days. Caffeine (6 mg/kg) was administered on one day and a placebo was administered on the other. The tibial nerve was stimulated at incremental intensities to create an H‐reflex recruitment curve prior to capsule administration (pretest) and 1 h later (posttest) on each day. The slope of H‐reflex recruitment curve normalized to that of the M wave (Hslp/Mslp) was compared (pretest to posttest). Caffeine increased spinal excitability 43 ± 17% (P < 0.05). Thus, caffeine may be used to safely increase spinal excitability in electrophysiological studies of the human neuromuscular system. Our results also suggest that caffeine intake should be controlled when the H reflex is used in diagnostic and experimental situations. Muscle Nerve 28: 359–364, 2003
Broadcasting in generalized chordal rings
Authors: Comellas F. , Hell P.
Published: August 2003

Broadcasting is an information dissemination process in which a message originating at one node of a communication network (modeled as an undirected graph) is sent to all other nodes by means of calls involving two nodes at a time, with each node participating in at most one call at any time. We are interested in efficient broadcasting in a class of cubic graphs known as generalized chordal rings. These graphs have been found useful for having a small diameter D, among graphs with a given number of vertices and maximum degree. We show that the minimum broadcast time in any generalized chordal ring is D, D + 1, or D + 2. For the generalized chordal rings of diameter D which have the greatest (or greatest‐known) number of nodes, we then evaluate exactly the minimum broadcast time. It turns out to be D + 1 when D is even and D + 2 when D is odd. For these purposes, we review the construction of these extremal generalized chodal rings. We also review the optimal broadcast schemes for infinite triangular grids, which we use to prove our bounds. Finally, we ask for the maximum number of nodes that can be informed by a broadcast in time t in any generalized chordal ring. We answer this completely for even t and almost completely for odd t. We use a geometric approach, based on plane tessellations. © 2003 Wiley Periodicals, Inc.
Improved preprocessing, labeling and scaling algorithms for the Weight‐Constrained Shortest Path Problem
Authors: Dumitrescu I. , Boland N.
Published: August 2003

Much has been written on shortest path problems with weight, or resource, constraints. However, relatively little of it has provided systematic computational comparisons for a representative selection of algorithms. Furthermore, there has been almost no work showing numerical performance of scaling algorithms, although worst‐case complexity guarantees for these are well known, nor has the effectiveness of simple preprocessing techniques been fully demonstrated. Here, we provide a computational comparison of three scaling techniques and a standard label‐setting method. We also describe preprocessing techniques which take full advantage of cost and upper‐bound information that can be obtained from simple shortest path information. We show that integrating information obtained in preprocessing within the label‐setting method can lead to very substantial improvements in both memory required and run time, in some cases, by orders of magnitude. Finally, we show how the performance of the label‐setting method can be further improved by making use of all Lagrange multiplier information collected in a Lagrangean relaxation first step. © 2003 Wiley Periodicals, Inc.
Reoptimizing the traveling salesman problem
Authors: Archetti Claudia , Bertazzi Luca , Speranza M. Grazia
Published: August 2003

In this paper, we study the reoptimization problems which arise when a new node is added to an optimal solution of a traveling salesman problem (TSP) instance or when a node is removed. We show that both reoptimization problems are NP‐hard. Moreover, we show that, while the cheapest insertion heuristic has a tight worst‐case ratio equal to 2 when applied to a TSP instance, it guarantees, in linear time, a tight worst‐case ratio equal to 3/2 when used to add the new node and that also the simplest heuristic to remove a node from the optimal tour guarantees a tight ratio equal to 3/2 in constant time. © 2003 Wiley Periodicals, Inc.
A linear algorithm for compact box‐drawings of trees
Authors: Hasan Masud , Rahman Md. Saidur , Nishizeki Takao
Published: August 2003

In a box‐drawing of a rooted tree, each node is drawn by a rectangular box of prescribed size, no two boxes overlap each other, all boxes corresponding to siblings of the tree have the same x‐coordinate at their left sides, and a parent node is drawn at a given distance apart from its first child. A box drawing of a tree is compact if it attains the minimum possible rectangular area enclosing the drawing. We give a linear‐time algorithm for finding a compact box‐drawing of a tree. A known algorithm does not always find a compact box‐drawing and takes time O(n2) if a tree has n nodes. © 2003 Wiley Periodicals, Inc.
The linear arrangement problem on recursively constructed graphs
Authors: Horton S. B. , Easton T. , Parker R. Gary
Published: August 2003

The linear arrangement problem on graphs is a relatively old and quite well‐known problem. Hard in general, it remains open on general recursive graphs (i.e., partial k‐trees, etc.), which is somewhat frustrating since most hard graph problems are easily solved on recursive graphs. In this paper, we examine the linear arrangement problem with respect to these structures. Included are some negative (complexity) results as well as a solvable case. © 2003 Wiley Periodicals, Inc.
On the use of Somigliana's formula and Fourier series for elasticity problems with circular boundaries
Authors: Crouch S. L. , Mogilevskaya S. G.
Published: August 2003

This paper considers the problem of an infinite, isotropic elastic plane containing an arbitrary number of non‐overlapping circular holes and isotropic elastic inclusions. The holes and inclusions are of arbitrary size and the elastic properties of all of the inclusions can, if desired, be different. The analysis is based on the two‐dimensional version of Somigliana's formula, which gives the displacements at a point inside a region V in terms of integrals of the tractions and displacements over the boundary S of this region. We take V to be the infinite plane, and S to be an arbitrary number of circular holes within this plane. Any (or all) of the holes can contain an elastic inclusion, and we assume for simplicity that all inclusions are perfectly bonded to the material matrix. The displacements and tractions on each circular boundary are represented as truncated Fourier series, and all of the integrals involved in Somigliana's formula are evaluated analytically. An iterative solution algorithm is used to solve the resulting system of linear algebraic equations. Several examples are given to demonstrate the accuracy and efficiency of the numerical method. Copyright © 2003 John Wiley & Sons, Ltd.
Optimal stress sampling points of plane triangular elements for patch recovery of nodal stresses
Authors: Rajendran S. , Liew K. M.
Published: August 2003

The existence of optimal stress sampling points in finite elements was first observed by Barlow. Knowledge of optimal stress sampling points is important in stress‐recovery methods such as the superconvergent patch recovery (SPR). Recently, MacNeal observed that Barlow points and Gaussian quadrature points are the same for the linear and quadratic bar elements, and different for the cubic bar element. Prathap proposed the best‐fit approach to predict the optimal sampling points, and showed that the best‐fit points coincide with Gaussian quadrature points not only for the linear and quadratic bar elements but also for the cubic bar element. In this paper, the best‐fit approach for predicting the optimal sampling points is extended to the linear and quadratic plane triangular elements, and the effectiveness of Barlow points, Gaussian points and best‐fit points as candidates of sampling points for the patch recovery of nodal stresses with these triangular elements is investigated for typical problems. The numerical results suggest that Barlow points do not exist for all strain/stress components, and Gaussian quadrature points which are the same as or close to the best‐fit points are better candidates for patch recovery. Copyright © 2003 John Wiley & Sons, Ltd.
Underwater shock‐free surface–structure interaction
Authors: Liu T. G. , Khoo B. C. , Yeo K. S. , Wang C.
Published: August 2003

A recently developed numerical method has been employed to evaluate the influence of free surface on shock loading in a cylindrical underwater explosion carried out near to both a free surface and a cylindrical rigid structure. In the usual simulation of underwater shock–structure interaction, the shock loading tends to accelerate/move the (rigid) structure only in the resultant force direction. The presence of a free surface and explosion bubble suggests the existence of a reverse loading and provides an additional torque (rotational moment) on the loaded structure. The numerical results also demonstrate the possible existence of a cavitation zone/region in the immediate vicinity of the free surface due to the near‐surface underwater explosion. Copyright © 2003 John Wiley & Sons, Ltd.
A parametric study on the fractal finite element method for two‐dimensional crack problems
Authors: Xie J. F. , Fok S. L. , Leung A. Y. T.
Published: August 2003

The Fractal Finite Element Method for calculating 2D stress intensity factors is modified by making the similarity ratio in the construction of the fractal mesh a variable. A parametric study is then carried out to examine the effects of the similarity ratio, the number of transformation terms, reduced integration and the initial crack opening angle on the quality of the numerical solutions. It is concluded that a large similarity ratio should be used to create the fractal mesh, and that reduced integration and a small initial crack opening angle may be used without producing significant errors in the solutions. Copyright © 2003 John Wiley & Sons, Ltd.
Knowledge‐based algorithms in fixed‐grid GA shape optimization
Authors: Woon Soon Yu , Tong Liyong , Querin Osvaldo M. , Steven Grant P.
Published: August 2003

Shape optimization through a genetic algorithm (GA) using discrete boundary steps and the fixed‐grid (FG) finite‐element analysis (FEA) concept was recently introduced by the authors. In this paper, algorithms based on knowledge specific to the FG method with the GA‐based shape optimization (FGGA) method are introduced that greatly increase its computational efficiency. These knowledge‐based algorithms exploit the information inherent in the system at any given instance in the evolution such as string structure and fitness gradient to self‐adapt the string length, population size and step magnitude. Other non‐adaptive algorithms such as string grouping and deterministic local searches are also introduced to reduce the number of FEA calls. These algorithms were applied to two examples and their effects quantified. The examples show that these algorithms are highly effective in reducing the number of FEA calls required hence significantly improving the computational efficiency of the FGGA shape optimization method. Copyright © 2003 John Wiley & Sons, Ltd.
A compromise programming method using multibounds formulation and dual approach for multicriteria structural optimization
Authors: Zhang W. H.
Published: August 2003

To enhance the reliability and efficiency of the multicriteria optimization procedure, a compromise programming method using multibounds formulation (MBF) is proposed in this paper. This method can be used either to obtain the Pareto optimum set or to find the ‘best’ Pareto optimum solution in the sense of having the minimum distance to the utopia point. By introducing a set of artificial design variables, it is shown that a simplified and easy‐to‐use formulation can be established for practical applications. Particularly, this formulation is well adapted to the efficient dual solution approach due to the convexity of objective function. Theoretically, based on the Kuhn–Tucker optimality conditions, demonstrations show that the new formulation is equivalent to its original form and thus retains the basic properties of the latter. Numerical examples will be solved to show the capacity of this method. Copyright © 2003 John Wiley & Sons, Ltd.
Sustainability and corporate evolution: Integrating vision and tools at Norm Thompson Outfitters
Authors: Smith Derek , Brown Michael S.
Published: August 2003

It's not easy to run a successful mail‐order business – and Norm Thompson Outfitters has
voluntarily made it even more difficult. The company is determined to be not only profitable, but as
environmentally responsible as possible. This latter goal has meant steep learning curves – in how to
design and construct the company headquarters building, in how to make catalogs from recycled paper, and, most
ambitiously, in how to work with suppliers toward products that have the least adverse environmental impact. And
they are sharing that hard‐won learning as they go, with whoever is willing to follow a path that
minimizes environmental damage. © 2003 Wiley Periodicals, Inc.
What businesses need now is better managerial performance
Authors: Rieley James B.
Published: August 2003

It's not just failures of governance at the highest levels that is threatening many companies, but
rather the more hands‐on leadership gaps along the management chain that are easier to identify –
and remedy. One way of identifying them is to look at leaders' priorities, ability to communicate
appropriately, motivation of employees, and management of key relationships. © 2003 Wiley
Periodicals, Inc.
Quality is not free for U.S. homebuilders
Authors: Dubey‐Villinger Niti , Dubey Krish K.
Published: August 2003

The unique nature of homebuilding gives rise to some quality control problems that cannot be solved by
industrial methods. According to the authors' research, quality in this industry can be ensured only by
more labor‐intensive training and oversight.
© 2003 Wiley Periodicals, Inc.
At Raytheon Six Sigma works, too, to improve HR management processes
Authors: Lanyon Sally
Published: August 2003

Raytheon has employed Six Sigma, traditionally used for improving manufacturing processes, as a broad tool
for creating customer value and changing culture. The HR function has also successfully applied Six Sigma to
make the company's people management processes more efficient, cost‐effective, and
user‐friendly, with the added benefit of enhancing HR's role as a full business partner with the
line organization. © 2003 Wiley Periodicals, Inc.
Retention interventions at Mutual of Omaha bring wide‐ranging changes
Authors: Hula Paul , Weinberg Raymond B.
Published: August 2003

In the current economy, more attention is being paid to the tight job market than to unwanted employee
turnover. But companies that look ahead to keeping their best employees when the job market loosens up might
consider deliberate retention strategies like the successful ones undertaken at Mutual of Omaha the last time
jobs were plentiful and good employees scarce. © 2003 Wiley Periodicals, Inc.
Hewlett‐Packard takes the waste out of leadership
Authors: Connolly Mickey , Burnett Susan
Published: August 2003

As Hewlett‐Packard faced formidable economic and industry challenges, along with the largest
high‐tech merger in history, it needed to quickly develop a new style of leadership aligned with the
company's new strategic direction. Recognizing that both the style and content of managers'
conversations affect the achievement of business goals, the company implemented a system that has trained HP
managers to increase the value of leadership conversations and decrease the conversational waste that
demotivates and decelerates valuable action. © 2003 Wiley Periodicals, Inc.
Managing human capabilities
Authors: Brache Alan P.
Published: August 2003

Human capabilities are people's unique sets of skills, knowledge, and personal values and beliefs. It is
useful for an organization to determine what human capabilities it needs—by examining its strategic,
business process, departmental, and job level requirements—and then identify what human capabilities it
currently possesses and the steps it can take to close any gaps. © 2002 Kepner‐Tregoe,
Inc.
A convergent three‐level finite difference scheme for solving a dual‐phase‐lagging heat transport equation in spherical coordinates
Authors: Dai Weizhong , Shen Lixin , Nassar Raja
Published: August 2003

Heat transport at the microscale is of vital importance in microtechnology applications. The heat transport equation is different from the traditional heat diffusion equation since a second‐order derivative of temperature with respect to time and a third‐order mixed derivative of temperature with respect to space and time are introduced. In this study, we consider the heat transport equation in spherical coordinates and develop a three‐level finite difference scheme for solving the heat transport equation in a microsphere. It is shown that the scheme is convergent, which implies that the scheme is unconditionally stable. Results show that the numerical solution converges to the exact solution. © 2003 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq 20: 60–71, 2004.
A high‐order finite difference discretization strategy based on extrapolation for convection diffusion equations
Authors: Sun Haiwei , Zhang Jun
Published: August 2003

We propose a new high‐order finite difference discretization strategy, which is based on the Richardson extrapolation technique and an operator interpolation scheme, to solve convection diffusion equations. For a particular implementation, we solve a fine grid equation and a coarse grid equation by using a fourth‐order compact difference scheme. Then we combine the two approximate solutions and use the Richardson extrapolation to compute a sixth‐order accuracy coarse grid solution. A sixth‐order accuracy fine grid solution is obtained by interpolating the sixth‐order coarse grid solution using an operator interpolation scheme. Numerical results are presented to demonstrate the accuracy and efficacy of the proposed finite difference discretization strategy, compared to the sixth‐order combined compact difference (CCD) scheme, and the standard fourth‐order compact difference (FOC) scheme. © 2003 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq 20: 18–32, 2004.
On a mixed finite element formulation of a second‐order quasilinear problem in the plane
Authors: Meddahi Salim
Published: August 2003

We analyze a mixed finite element discretization of a second‐order quasilinear problem based on the Raviart‐Thomas space. We prove that the discrete problem is solvable and provide a local uniqueness result for the solution. We also obtain optimal order L2‐error estimates for both the scalar variable and the associated flux. The main feature of our method is that it is free from the boundness conditions required in previous works on the coefficients of the quasilinear operator. © 2003 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq 20: 90–103, 2004.
Lagrange interpolation and finite element superconvergence
Authors: Li Bo
Published: August 2003

We consider the finite element approximation of the Laplacian operator with the homogeneous Dirichlet boundary condition, and study the corresponding Lagrange interpolation in the context of finite element superconvergence. For d‐dimensional Qk‐type elements with d ≥ 1 and k ≥ 1, we prove that the interpolation points must be the Lobatto points if the Lagrange interpolation and the finite element solution are superclose in H1 norm. For d‐dimensional Pk‐type elements, we consider the standard Lagrange interpolation—the Lagrange interpolation with interpolation points being the principle lattice points of simplicial elements. We prove for d ≥ 2 and k ≥ d + 1 that such interpolation and the finite element solution are not superclose in both H1 and L2 norms and that not all such interpolation points are superconvergence points for the finite element approximation. © 2003 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq 20: 33–59, 2004.
Local defect correction with slanting grids
Authors: Graziadei M. , Mattheij R. M. M. , ten Thije Boonkkamp J. H. M.
Published: August 2003

The local defect correction (LDC) method is used to solve a convection‐diffusion‐reaction problem that contains a high‐activity region in a relatively small part of the domain. The improvement of the solution on a coarse grid is obtained by introducing a correction term computed from a local fine‐grid solution. This article studies problems where the high‐activity region is covered with a rectangular fine grid not aligned with the axes of the global domain. This study shows that the resulting method is less expensive than both a uniform refinement and tensor product grid method. © 2003 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq 20: 1–17, 2004.
Fast direct solver for Poisson equation in a 2D elliptical domain
Authors: Lai Ming‐Chih
Published: August 2003

In this article, we extend our previous work M.‐C. Lai and W.‐C. Wang, Numer Methods Partial Differential Eq 18:56–68, 2002 for developing some fast Poisson solvers on 2D polar and spherical geometries to an elliptical domain. Instead of solving the equation in an irregular Cartesian geometry, we formulate the equation in elliptical coordinates. The solver relies on representing the solution as a truncated Fourier series, then solving the differential equations of Fourier coefficients by finite difference discretizations. Using a grid by shifting half mesh away from the pole and incorporating the derived numerical boundary value, the difficulty of coordinate singularity can be elevated easily. Unlike the case of 2D disk domain, the present difference equation for each Fourier mode is coupled with its conjugate mode through the numerical boundary value near the pole; thus, those two modes are solved simultaneously. Both second‐ and fourth‐order accurate schemes for Dirichlet and Neumann problems are presented. In particular, the fourth‐order accuracy can be achieved by a three‐point compact stencil which is in contrast to a five‐point long stencil for the disk case. © 2003 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq 20: 72–81, 2004
A variational method of optimal control problems for nonlinear Schrödinger equations
Authors: Subaşi Murat
Published: August 2003

Calculating the control function that is in the coefficients of the nonlinear Schrodinger equation and minimizes the objective functional consisting of two integrals is main aim of this article. After proving the existence and uniqueness of the solution, we have constituted an algorithm using the method of gradient of projection. Results are tested on a quantum‐mechanical problem. © 2003 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq 20: 82–89, 2004.
A corrected smooth particle hydrodynamics method for the simulation of debris flows
Authors: Rodriguez‐Paz M. X. , Bonet J.
Published: August 2003

This article presents the development and application of a corrected smooth particle hydrodynamics (CSPH) code to the simulation of debris flow and avalanches. The advantages of a mesh‐free method over other traditional numerical methods such as the finite element method are discussed. A new frictional approach for the boundary conditions and modified constitutive equations are introduced in the SPH method. The resulting technique is then applied for the simulation of debris flows, comparing the results with those obtained from experiments reported by other researchers. © 2003 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq 20: 140–163, 2004.
Conservative flux recovery from the Q1 conforming finite element method on quadrilateral grids
Authors: Chou So‐Hsiang , He Songnian , Lin Wen‐Wei
Published: August 2003

Compared with standard Galerkin finite element methods, mixed methods for second‐order elliptic problems give readily available flux approximation, but in general at the expense of having to deal with a more complicated discrete system. This is especially true when conforming elements are involved. Hence it is advantageous to consider a direct method when finding fluxes is just a small part of the overall modeling processes. The purpose of this article is to introduce a direct method combining the standard Galerkin Q1 conforming method with a cheap local flux recovery formula. The approximate flux resides in the lowest order Raviart‐Thomas space and retains local conservation property at the cluster level. A cluster is made up of at most four quadrilaterals. © 2004 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq 20: 104–127, 2004
Least‐squares spectral collocation method for the Stokes equations
Authors: Kim Sang Dong , Lee Hyung‐Chun , Shin Byeong Chun
Published: August 2003

First‐order system least‐squares spectral collocation methods are presented for the Stokes equations by adopting the first‐order system and modifying the least‐squares functionals in 2. Then homogeneous Legendre and Chebyshev (continuous and discrete) functionals are shown to be elliptic and continuous with respect to appropriate product weighted norms. The spectral convergence is analyzed for the proposed methods with some numerical experiments. © 2003 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq 20: 128–139, 2004
Analysis of gial acidic fibrillary protein in the human entorhinal cortex during aging and in Alzheimer's disease
Authors: Porchet Raymonde , Probst Alphonse , Bouras Constantin , Dráberová Eduarda , Dráber Pavel , Riederer Beat M.
Published: August 2003

Glial fibrillary acidic protein, GFAP, is a major intermediate filament protein of glial cells and major cytoskeletal structure in astrocytes. The entorhinal cortex has a key role in memory function and is one of the first brain areas to reveal hallmark structures of Alzheimer's disease and therefore provides an ideal tissue to investigate incipient neurodegenerative changes. Here we have analyzed age‐ and disease‐related occurrence and composition of GFAP in the human entorhinal cortex by using one‐ and two‐dimensional electrophoresis, Western blots and immunocytochemistry combined with confocal microscopy. A novel monoclonal antibody, GF‐02, was characterized that mainly reacted with intact GFAP molecules and indicated that more acidic and soluble GFAP forms were also more susceptible to degradation. GFAP and vimentin increased with aging and in Alzheimer's disease (AD). Two‐dimensional electrophoresis and Western blots revealed a complex GFAP pattern, both in aging and AD with different modification and degradation forms. Immunohistochemistry indicated that reactive astrocytes mainly accumulated in relation to neurofibrillary tangles and senile plaques in deeper entorhinal cortex layers. GFAP may be used as an additional but not exclusive diagnostic tool in the evaluation of neurodegenerative diseases because its levels change with age and respond to senile plaque and tangle formation.
Neuro‐fuzzy structural classification of proteins for improved protein secondary structure prediction
Authors: Hering Joachim A. , Innocent Peter R. , Haris Parvez I.
Published: August 2003

Fourier transform infrared (FTIR) spectroscopy is a very flexible technique for characterization of protein secondary structure. Measurements can be carried out rapidly in a number of different environments based on only small quantities of proteins. For this technique to become more widely used for protein secondary structure characterization, however, further developments in methods to accurately quantify protein secondary structure are necessary. Here we propose a structural classification of proteins (SCOP) class specialized neural networks architecture combining an adaptive neuro‐fuzzy inference system (ANFIS) with SCOP class specialized backpropagation neural networks for improved protein secondary structure prediction. Our study shows that proteins can be accurately classified into two main classes “all alpha proteins” and “all beta proteins” merely based on the amide I band maximum position of their FTIR spectra. ANFIS is employed to perform the classification task to demonstrate the potential of this architecture with moderately complex problems. Based on studies using a reference set of 17 proteins and an evaluation set of 4 proteins, improved predictions were achieved compared to a conventional neural network approach, where structure specialized neural networks are trained based on protein spectra of both “all alpha” and “all beta” proteins. The standard errors of prediction (SEPs) in % structure were improved by 4.05% for helix structure, by 5.91% for sheet structure, by 2.68% for turn structure, and by 2.15% for bend structure. For other structure, an increase of SEP by 2.43% was observed. Those results were confirmed by a “leave‐one‐out” run with the combined set of 21 FTIR spectra of proteins.
The role of bioinformatics in two‐dimensional gel electrophoresis
Authors: Dowsey Andrew W. , Dunn Michael J. , Yang Guang‐Zhong
Published: August 2003

Over the last two decades, two‐dimensional electrophoresis (2‐DE) gel has established itself as thede factoapproach to separating proteins from cell and tissue samples. Due to the sheer volume of data and its experimental geometric and expression uncertainties, quantitative analysis of these data with image processing and modelling has become an actively pursued research topic. The results of these analyses include accurate protein quantification, isoelectric point and relative molecular mass estimation, and the detection of differential expression between samples run on different gels. Systematic errors such as current leakage and regional expression inhomogeneities are corrected for, followed by each protein spot in the gel being segmented and modelled for quantification. To assess differential expression of protein spots in different samples run on a series of two‐dimensional gels, a number of image registration techniques for correcting geometric distortion have been proposed. This paper provides a comprehensive review of the computation techniques used in the analysis of 2‐DE gels, together with a discussion of current and future trends in large scale analysis. We examine the pitfalls of existing techniques and highlight some of the key areas that need to be developed in the coming years, especially those related to statistical approaches based on multiple gel runs and image mining techniques through the use of parallel processing based on cluster computing and the grid technology.
Proteomic changes in renal cancer and co‐ordinate demonstration of both the glycolytic and mitochondrial aspects of the Warburg effect
Authors: Unwin Richard D. , Craven Rachel A. , Harnden Patricia , Hanrahan Sarah , Totty Nick , Knowles Margaret , Eardley Ian , Selby Peter J. , Banks Rosamonde E.
Published: August 2003

Renal cell carcinoma (RCC) is the tenth most common cancer although the incidence is increasing. The main clinical problems stem from the relatively late presentation of many patients due to the often asymptomatic nature of the illness, and the relative insensitivity of metastatic disease to conventional chemotherapy and radiotherapy. Despite increasing knowledge of some of the genetic changes underlying sporadic renal cancer such as those involving the Von Hippel Lindau (VHL) gene, many of the underlying pathophysiological changes are ill‐defined and there remains a need for the identification of disease markers for use in diagnosis and prognosis or as potential therapeutic targets. This study has used a proteomic approach, based on two‐dimensional gel electrophoresis and mass spectrometry, to compare the protein profiles of conventional RCC tissue with patient‐matched normal kidney cortex. Sequencing of 32 protein spots with significantly increased expression in RCC samples (≥ 4/6 patients) and 41 proteins whose levels decreased (6/6 patients) confirmed several previously known RCC‐associated changes such as increases in Mn‐superoxide dismutase, lactate dehydrogenase‐A, aldolase A and C, pyruvate kinase M2, and thymidine phosphorylase. Additionally, several previously unknown changes were identified, including increased expression of three members of the annexin family and increased levels of the actin depolymerisation factor cofilin. The Warburg effect was also demonstrated with the identification of increases in proteins involved in the majority of steps in the glycolytic pathway and decreases in the gluconeogenic reactions, together with a parallel decrease in several mitochondrial enzymes. A number of the alterations seen were further confirmed in additional samples by immunohistochemistry, Western blotting, and laser capture microdissection.
Sample preparation for two‐dimensional gel electrophoresis
Authors: Shaw Margaret M. , Riederer Beat M.
Published: August 2003

The choice of sample preparation protocol is a critical influential factor for isoelectric focusing which in turn affects the two‐dimensional gel result in terms of quality and protein species distribution. The optimal protocol varies depending on the nature of the sample for analysis and the properties of the constituent protein species (hydrophobicity, tendency to form aggregates, copy number) intended for resolution. This review explains the standard sample buffer constituents and illustrates a series of protocols for processing diverse samples for two‐dimensional gel electrophoresis, including hydrophobic membrane proteins. Current methods for concentrating lower abundance proteins, by removal of high abundance proteins, are also outlined. Finally, since protein staining is becoming increasingly incorporated into the sample preparation procedure, we describe the principles and applications of current (and future) pre‐electrophoretic labelling methods.
Use of proteomics and physiological characteristics to elucidate ecotoxic effects of methyl tert‐butyl ether in Pseudomonas putida KT2440
Authors: Krayl Martin , Benndorf Dirk , Loffhagen Norbert , Babel Wolfgang
Published: August 2003

We monitored rates of growth, ATP‐synthesis, respiration, and death to assess the sensitivity of the model organism Pseudomonas putida KT2440 to methyl tert‐butyl ether (MTBE), and its degree of toxicity. The physiological data obtained suggested that the energy conservation system was the most sensitive site. However, with the help of proteomic analysis we obtained further information and deeper insight into the molecular mechanisms involved. This analysis indicated that sensitivity involves oxidative stress since alkylhydroperoxide reductase C (AhpC) and two superoxide dismutases (SodM, SodF) were amplified in the presence of MTBE. Thus, proteomics has major advantages in ecotoxicological investigations where the aims include elucidation of the molecular mechanisms as well as characterization of the ecostress and the potency of the stressor(s).
A potential cerebrospinal fluid and plasmatic marker for the diagnosis of Creutzfeldt‐Jakob disease
Authors: Guillaume Elisabeth , Zimmermann Catherine , Burkhard Pierre R. , Hochstrasser Denis F. , Sanchez Jean‐Charles
Published: August 2003

The recent occurrence of the new variant of Creutzfeldt‐Jakob disease (CJD), probably transmitted to humans by cattle affected by the bovine form of spongiform encephalopathy, has generated renewed interest in the clinical issues related to human spongiform encephalopathies. Using the current set of diagnostic tools, these rare but devastating conditions may be difficult to diagnose with accuracy before death. The objective of the present communication is to describe the discovery of a potential cerebrospinal fluid (CSF) and plasmatic marker of human transmissible spongiform encephalopathies. A preliminary two‐dimensional electrophoresis approach highlighted a potential neurodegenerative disorder marker called the fatty acid binding protein, FABP. Its heart form, H‐FABP, was investigated in a small group of CJD affected patients (n = 8 ) by an immunoassay approach. The amount of FABP appeared to be significantly (p≤ 0.05) increased in all tested samples. H‐FABP detection could therefore be helpful as a blood screening test for a pre‐mortem diagnosis of the disease and also to prevent the risk of iatrogenic transmission of CJD through blood transfusion.