bluuebunny/crossref_metadata_2025 huggingface dataset:
Immobilization of DNA on 11‐mercaptoundecanoic acid‐modified gold (111) surface for atomic force microscopy imaging
Authors: Song Yonghai , Li Zhuang , Liu Zhiguo , Wei Gang , Wang Li , Sun Lanlan
Published: October 2005

Immobilized DNA on preformed 11‐mercaptoundecanoic acids (MUDA) self‐assembled monolayers (SAMs) on a gold (111) surface was bound by a divalent cation bridges was imaged by atomic force microscopy (AFM). The DNA immobilization was attributed to the formation of ionic bridges between the carboxylate groups of MUDA and the phosphate groups of DNA. AFM images revealed that DNA molecules could be immobilized strongly enough to permit stable and reproducible imaging. The effect of different bridge cations, such as Mg2+, Zn2+ and Cu2+, and the pH of DNA assembled solution on immobilization and conformation of DNA was studied. Plasmid DNA pBR 322/Pst I molecules were straightened by using a molecular combing technique on the MUDA surface. Microsc. Res. Tech. 68:59–64, 2005. © 2005 Wiley‐Liss, Inc.
Chlorhexidine‐induced ultrastructural alterations in oral biofilm
Authors: Vitkov L. , Hermann A. , Krautgartner W.D. , Herrmann M. , Fuchs K. , Klappacher M. , Hannig M.
Published: October 2005

Chlorhexidine, the most used biocide in periodontology, alters the permeability of the bacterial cell membrane. However, the chlorhexidine‐induced morphological alterations in the oral biofilm have not been studied. To examine the effects of chlorhexidine on oral biofilm on an electron microscopic level, gingival epithelial cells with attached biofilm were collected from 10 volunteers, subjected to 0.1% chlorhexidine for 1 or 5 min, stained with ruthenium red‐tetroxide, and analyzed by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). SEM visualized the bacterial glycocalyces and the biofilm matrix on the biofilm surface; however, no chlorhexidine‐induced alterations were observed. TEM revealed loss of bacterial membrane integrity and fimbrial disintegration in a few bacteria. In the proximity of these alterations, a restricted matrix disintegration was also observed. However, the chlorhexidine‐induced alterations only effected a minor part of the oral biofilm and did not cause its disintegration. These findings suggest the insufficient efficiency of chlorhexidine against oral biofilm. Microsc. Res. Tech. 68:85–89, 2005. © 2005 Wiley‐Liss, Inc.
Natriuretic peptide expression in the heart of the TTR‐ANP transgenic mouse—Comparison to the normal heart
Authors: Lundberg Simon , Hansson Magnus
Published: October 2005

The transgenic mice, TTR‐ANP, carrying a fusion gene comprising the transthyretin promoter and the atrial natriuretic peptide (ANP) structural sequence, are known to have elevated ANP plasma levels as well as lowered blood pressure levels. On the other hand, it is not known whether these transgenic mice show changed natriuretic peptide (NP) expression patterns in the heart. Therefore, we examined the distribution of NPs in the myocardium and the conduction system of transgenic mice overexpressing ANP, as well as in wild‐type littermates. The hearts were serially sectioned and processed for immunohistochemistry, with antisera against ANP and brain natriuretic peptide (BNP). Florescence microscopy was performed for qualitative analysis. Immunoreactivity for ANP and BNP was detected to a similar degree in the conduction system of both transgenic and wild‐type mice. The nodal tissues never exhibited immunoreactions for ANP or BNP, whereas Purkinje fibers of the atrioventricular junctional tissue, bundle branches, and the peripheral Purkinje fiber network exhibited specific immunoreactivity. Atrial and ventricular myocytes of both transgenic and wild‐type mice exhibited ANP and BNP to a similar extent. This is the first study examining the expression pattern of NPs in the cardiac conduction system of the mouse as well as the pattern of ANP and BNP expression in the conduction system of TTR‐ANP transgenic mice and its wild‐type siblings. The findings in this study suggest that ectopic ANP expression and release do not repress cardiac production of ANP. Microsc. Res. Tech. 68:97–106, 2005. © 2005 Wiley‐Liss, Inc.
Atomic force and scanning electron microscopy of atmospheric particles
Authors: Barkay Zahava , Teller Amit , Ganor Eliezer , Levin Zev , Shapira Yoram
Published: October 2005

Atomic force microscopy (AFM) and scanning electron microscopy with energy dispersive spectroscopy (SEM–EDS) have been used for both morphological and elemental mass analysis study of atmospheric particles. As part of the geometrical particle analysis, and in addition to the traditional height profile measurement of individual particles, AFM was used to measure the volume relative to the projection area for each particle separately, providing a particle shape model. The element identification was done by the EDS analysis, and the element mass content was calculated based on laboratory calibration with particles of known composition. The SEM–EDS mass measurements from two samples collected at 150 and 500 m above the surface of the Mediterranean Sea were found to be similar to mass calculations derived from the AFM volume measurements. The AFM results show that the volume of most of the aerosols that were identified as soluble marine sulfate and nitrate aerosol particles can be better estimated using cylindrical shapes than spherical or conical geometry. Microsc. Res. Tech. 68:107–114, 2005. © 2005 Wiley‐Liss, Inc.
A method for finding the station where climatic trends are most representative for a region
Authors: Huth Radan
Published: October 2005

A method is proposed to identify the station where trends in several climatic elements are most representative for a whole region. It is based on principal component analysis of trend magnitudes. The most representative is the station at which the distance of principal component scores from zero is the smallest. The method is applied to seasonal and annual means of 10 climatic elements at 20 stations in the Czech Republic. It succeeds in finding stations outlying because of their inhomogeneity or mountain‐summit position. The degree of representativeness of stations varies considerably among seasons. The trends in individual climatic elements at the most representative station are usually close to the trends in the spatial mean, but on some occasions, they considerably differ from each other. Copyright © 2005 Royal Meteorological Society.
Structural characterization of blends containing both PVDF and natural rubber latex
Authors: Simoes R. D. , Job A. E. , Chinaglia D. L. , Zucolotto V. , Camargo‐Filho J. C. , Alves N. , Giacometti J. A. , Oliveira O. N. , Constantino C. J. L.
Published: October 2005

Films containing different volumes of latex of natural rubber (NR) in a fixed mass of poly (vinylidene fluoride) (PVDF) powder were fabricated by compressing under annealing a mixture of both materials without using any solvent. This is an important issue keeping in mind that these films have to be used in the future as biomaterials in different applications once the solvents that are used to dissolve the PVDF become toxic to human. The films with different percentage of latex in PVDF were characterized using micro‐Raman scattering and Fourier transform infrared absorption (FTIR) spectroscopies, thermomechanical techniques using thermogravimetry (TG), differential scanning calorimetry (DSC), dynamical‐mechanical analysis (DMA) and scanning electron microscopy (SEM). The results showed that the latex of NR and PVDF do not interact chemically, leading to the formation of a polymeric blend with high thermal stability and mechanical properties suitable for applications involving bone (prostheses, for instance). Besides, the results recorded using the micro‐Raman technique revealed that for a fixed amount of PVDF the higher the amount of latex in the blend, the better the miscibility between both materials. Copyright © 2005 John Wiley & Sons, Ltd.
Surface‐enhanced Raman scattering (SERS) of random silver or gold particle arrays on aminodextran‐coated polystyrene beads
Authors: Siiman Olavi , Ledis Stephen
Published: October 2005

Citrate and/or chemically modified aminodextran (Amdex) SERS bands were detected from silver particle‐Amdex‐polystyrene (PS) beads either as singlets or small clusters, prepared by reaction between aqueous silver nitrate, Amdex‐coated PS beads, and aqueous sodium citrate solution. However, citrate on individual silver or gold particles of the same size was not detected with 633‐nm excitation. SERS of dyes such as rhodamine 6 G was readily observed on individual silver particles or on the gold beads. Three distinct modes of citrate/modified‐Amdex binding to the silver particle‐Amdex‐PS beads were characterized: (1) exchangeable citrate bound through one or more carboxylate groups—citrate could be washed away with H2O or D2O; displaced by successively greater concentrations of R6G; or squeezed out mechanically by applying the pressure of a second coverslip on top of a droplet of bead suspension; (2) nonexchangeable Amdex bound to silver via a primary alcoholate ion of oxidized, glutaraldehyde‐cross‐linked Amdex; and (3) nonexchangeable oxidized Amdex bound to silver via carboxylate group(s) but with H/D exchangeable alcohol hydrogen atom. That oxidation of the glucopyranose residues of Amdex on PS beads had taken place by Ag(I) as silver nitrate in aqueous solution to split out carboxylate groups was first identified from their characteristic vibrational modes in the SERS spectra of colloidal silver suspensions. Minimum amplification factors for (R6G on Ag)/(R6G on Au) with 633‐nm excitation were estimated as 1 × 1015/1 × 1011. An extra SERS enhancement of about 1000‐fold due to multiplicity of metal particles per bead was included. Copyright © 2005 John Wiley & Sons, Ltd.
Gold‐polymer nanocomposites: studies of their optical properties and their potential as SERS substrates
Authors: Giesfeldt Kathleen S. , Connatser R. Maggie , De Jesús Marco A. , Dutta Pampa , Sepaniak Michael J.
Published: October 2005

Polymer‐nanometallic‐particle composites have demonstrated technological potential owing to their unique optical and electrical properties. In this article, we report on composites prepared via physical vapor deposition of gold metal onto pliable polydimethylsiloxane (PDMS) polymer. Rapid Au diffusion and nanometallic‐particle formation in a phase‐separated surface layer of the PDMS creates unique tunable sub‐surface‐based composites. The rate of deposition and average Au thickness can be manipulated to tune the optical properties, which are studied by visible wavelength optical extinction spectrometry and surface‐enhanced Raman scattering (SERS). DC conductivity measurements were made during Au deposition to study percolation conditions for the materials and depth profiling was performed by X‐ray photoelectron spectrometry (XPS). This work presents the use of Au‐PDMS nanocomposites in combination with a sample translation technique (STT) for the improved SERS qualitative and quantitative analysis. This translation approach considerably improves the reproducibility and the sensitivity of the technique by minimizing the thermal and photolytic effects inherent in SERS. The Au‐PDMS nanocomposites exhibit an affinity for amine and nitro‐based compounds that are biologically relevant and point toward the potential for being used as substrates for biologically based SERS experiments. Sample Raman spectra with the nanocomposite under STT‐SERS conditions are included. Copyright © 2005 John Wiley & Sons, Ltd.
Accessing Chain Length Dependent Termination Rate Coefficients of Methyl Methacrylate (MMA) via the Reversible Addition Fragmentation Chain Transfer (RAFT) Process
Authors: Johnston‐Hall Geoffrey , Theis Alexander , Monteiro Michael J. , Davis Thomas P. , Stenzel Martina H. , Barner‐Kowollik Christopher
Published: October 2005

Summary: The RAFT‐CLD‐T methodology is demonstrated to be not only applicable to 1‐substituted monomers such as styrene and acrylates, but also to 1,1‐disubstituted monomers such as MMA. The chain length of the terminating macromolecules is controlled by CPDB in MMA bulk free radical polymerization at 80 °C. The evolution of the chain length dependent termination rate coefficient, k, was constructed in a step‐wise fashion, since the MMA/CPDB system displays hybrid behavior (between conventional and living free radical polymerization) resulting in initial high molecular weight polymers formed at low RAFT agent concentrations. The obtained CLD of kt in MMA polymerizations is compatible with the composite model for chain length dependent termination. For the initial chain‐length regime, up to a degree of polymerization of 100, kt decreases with α (in the expression k = k · i−α) being close to 0.65 at 80 °C. At chain lengths exceeding 100, the decrease is less pronounced (affording an α of 0.15 at 80 °C). However, the data are best represented by a continuously decreasing non‐linear functionality implying a chain length dependent α.

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Cover Picture: Macromol. Mater. Eng. 10/2005
Authors: Holtze Christian , Landfester Katharina , Antonietti Markus
Published: October 2005

Cover: The picture on the cover shows a high resolution SEM picture of a polymer network containing water nanodroplets, made by bulk polymerization of a gelled miniemulsion. Further details can be found in the article by C. Holtze, K. Landfester, and M. Antonietti* on page 1025.
Qigong exercise for the symptoms of Parkinson's disease: A randomized, controlled pilot study
Authors: Schmitz‐Hübsch Tanya , Pyfer Derek , Kielwein Karin , Fimmers Rolf , Klockgether Thomas , Wüllner Ullrich
Published: October 2005

Irrespective of limited evidence, not only traditional physiotherapy, but also a wide array of complementary methods are applied by patients with Parkinson's disease (PD). We evaluated the immediate and sustained effects of Qigong on motor and nonmotor symptoms of PD, using an add‐on design. Fifty‐six patients with different levels of disease severity (mean age/standard deviation [SD], 63.8/7.5 years; disease duration 5.8/4.2 years; 43 men [76%]) were recruited from the outpatient movement disorder clinic of the Department of Neurology, University of Bonn. We compared the progression of motor symptoms assessed by Unified Parkinson's Disease Rating Scale motor part (UPDRS‐III) in the Qigong treatment group (n = 32) and a control group receiving no additional intervention (n = 24). Qigong exercises were applied as 90‐minute weekly group instructions for 2 months, followed by a 2 months pause and a second 2‐month treatment period. Assessments were carried out at baseline, 3, 6, and 12 months. More patients improved in the Qigong group than in the control group at 3 and 6 months (P = 0.0080 at 3 months and P = 0.0503 at 6 months; Fisher's exact test). At 12 months, there was a sustained difference between groups only when changes in UPDRS‐III were related to baseline. Depression scores decreased in both groups, whereas the incidence of several nonmotor symptoms decreased in the treatment group only. © 2005 Movement Disorder Society
Anticholinesterase effect on motor kinematic measures and brain activation in Parkinson's disease
Authors: Mentis Marc J. , Delalot Dominique , Naqvi Hassan , Gordon Mark F. , Gudesblatt Mark , Edwards Christine , Donatelli Luke , Dhawan Vijay , Eidelberg David
Published: October 2005

Anticholinesterase (AChE) drugs are being prescribed off label for nonmotor symptoms in Parkinson's disease (PD). Theoretically, these drugs can impair motor function. A small literature suggests AChE therapy has little effect on clinical motor evaluation; however, no study has made objective motor kinematic measures or evaluated brain function. We hypothesized that even if clinical examination was normal in PD patients on dopamine therapy, (1) sensitive kinematic measures would be abnormal during AChE therapy or (2) normal kinematic measures would be maintained by compensatory brain activation. We carried out a randomized, double‐blind, placebo‐controlled trial of 8 weeks donepezil (10 mg/day) in 17 PD subjects. Subjects carried out a computerized motor task during a positron emission tomography (PET) scan before starting the drug and again after 8 weeks of donepezil or placebo. Kinematic measures of motor function and PET scans were analyzed to compare the effects of donepezil and placebo. Neither placebo nor donepezil altered motor kinematic measures. Furthermore, movement integrity while on donepezil was maintained without compensatory brain activity. Donepezil 10 mg/day can be given for nonmotor symptoms in PD without adverse motor effects or compensatory brain activity. © 2005 Movement Disorder Society
REM sleep behavior disorder, hallucinations, and cognitive impairment in Parkinson's disease
Authors: Sinforiani Elena , Zangaglia Roberta , Manni Raffaele , Cristina Silvano , Marchioni Enrico , Nappi Giuseppe , Mancini Francesca , Pacchetti Claudio
Published: October 2005

The objective of this study was to evaluate the relationship between REM sleep behavior disorder (RBD), hallucinations, and cognitive impairment in Parkinson's disease (PD). One hundred and ten PD patients, divided into three groups (without RBD or hallucinations; with RBD but no hallucinations; with RBD and hallucinations), were submitted to neuropsychological evaluation. The group without RBD and hallucinations showed normal neuropsychological tests when compared to normal controls. The group with hallucinations was characterized by a more severe cognitive impairment affecting both short‐ and long‐term memory, logical abilities, and frontal functions, while the RBD‐only group presented frontal impairment. The hypothesis that RBD in PD can be considered a risk factor not only of the hallucinations but also of more severe and diffuse cognitive abnormalities needs to be strengthened through a longitudinal evaluation. © 2005 Movement Disorder Society
An existence theorem for Poiseuille flow with surface tension in an open channel
Authors: Hansen Erik B. , Solonnikov V. A. , Brosowski B.
Published: October 2005

Poiseuille‐type flow in an open channel is studied taking surface tension and wall adhesion into account. A proof is presented of the existence of a solution under certain conditions.
On the ‘one and one‐half dimensional’ relativistic Vlasov–Maxwell system
Authors: Glassey Robert , Schaeffer Jack
Published: October 2005

The time evolution of a collisionless plasma is studied in the case when the Viasov density ƒ is a function of the time, one space variable and two velocity variables. The electromagnetic fields E, B also have a special structure, and the magnetic field B is non‐trivial. It is shown that smooth, consistent initial values generate a uniquc smooth global solution.
An improved boundary element method for the charge density of a thin electrified plate in ℝ3
Authors: Ervin V. J. , Stephan E. P. , El‐Seoud S. Abou
Published: October 2005

A weakly singular integral equation of the first kind on a plane surface piece Γ is solved approximately via the Galerkin method. The determination of the solution of this integral equation (with the single‐layer potential) is a classical problem in physics, since its solution represents the charge density of a thin, electrified plate Γ loaded with some given potential. Using piecewise constant or piecewise bilinear boundary elements we derive asymptotic estimates for the Galerkin error in the energy norm and analyse the effect of graded meshes. Estimates in lower order Sobolev norms are obtained via the Aubin–Nitsche trick. We describe in detail the numerical implementation of the Galerkin method with both piecewise‐constant and piecewise‐linear boundary elements. Numerical experiments show experimental rates of convergence that confirm our theoretical, asymptotic results.
An asymptotic‐numerical approach to the coronal loop problem
Authors: Verhulst F. , Zegeling P. A.
Published: October 2005

The coronal loop problem is characterized by mixed boundary conditions and the loop length condition, which is global. Using singular perturbation methods one can identify and construct two boundary layers at the base of the loop.

Extending this to a combined asymptotic‐numerical treatment it is possible to construct two static solutions satisfying the same conditions; this unusual feature arises from the presence of the first boundary layer, which corresponds with a steep temperature gradient and an energy balance dominated by conduction and radiation losses.
The transient behaviour of multidimensional PN‐diodes in low injection
Authors: Schmeiser Christian , Unterreiter Andreas
Published: October 2005

An initial boundary value problem modelling the transient behaviour of a pn‐junction semiconductor diode is simplified by formal asymptotics, where the scaled minimal Debye length and the scaled intrinsic number are considered as small parameters. The implicit assumption on the biasing situation is that of low injection. The simplified model is shown to be equivalent to an integral relation between the evolution of the current and of the contact voltage. A simple switching application is governed by a non‐linear Volterra integral equation for the current. This equation is shown to possess a unique solution globally in time converging to the unique steady state.
Non‐linear parabolic problem associated with the penetration of a magnetic field into a substance
Authors: Long Nguyen Thanh , Alain Pham Ngoc Dinh
Published: October 2005

We study the following initial and boundary value problem:
equation image
In section 1, with u0 in L2(Ω), f continuous such that f(u) + ϵ non‐decreasing for ϵ positive, we prove the existence of a unique solution on (0,T), for each T > 0. In section 2 it is proved that the unique soluition u belongs to L2(0, T; H ∩ H2) ∩ L∞(0, T; H) if we assume u0 in H and f in C1(ℝ,ℝ). Numerical results are given for these two cases.
Modelling of dynamic networks of thin elastic plates
Authors: Lagnese J. E. , Leugering G.
Published: October 2005

The purpose of this paper is to derive junction conditions for networks of thin elastic plates and to analyse the dynamic equations of such networks. Junction conditions for networks of Kirchhoff plates and networks of Reissner–Mindlin plates are derived based on geometric considerations of the deformation at a junction. It is proved that the dynamic system which describes the Reissner–Mindlin network is well‐posed is an appropriate energy space. It is further established that the Kirchhoff network is obtained in the limit of the Reissner–Mindlin network as the shear moduli go to infinity.
A normal crack in an elastic half‐space with stress‐free surface
Authors: Martin P. A. , Päivärinta L. , Rempel S.
Published: October 2005

The problem of an elastic half‐space with stress‐free surface and a crack of arbitrary shape with prescribed displacements or tractions is reduced to an equivalent system of integral equations on the crack. For a pressurized crack in a plane perpendicular to the free surface, a scalar integral equation is derived. In properly chosen function spaces, unique solvability of the integral equation and regularity of solutions for regular data are proven.
Classical solutions of two‐dimensional stokes problems on non‐smooth domains. Part 1: The radon integral operators
Authors: Lubuma Jean Mbaro‐Saman
Published: October 2005

The applicability of the Neumann indirect method of potentials to the Dirichlet and Neumann problems for the two‐dimensional Stokes operator on a non‐smooth boundary Γ is subject to two kinds of sufficient and/or necessary conditions on Γ. The first one, occurring in electrostatic, is equivalent to the boundedness onC(Γ) of the velocity double‐layer potentialWas well as to the existence of jump relations of potentials. The second condition, which forces Γ to be a simple rectifiable curve and which, compared to the Laplacian, is a stronger restriction on the corners of Γ, states that the Fredholm radius ofWis greater than 2. Under these conditions, the Radon boundary integral equations defined by the above‐mentioned jump relations are solvable by the Fredholm theory; the double‐ (for Dirichlet) and the single‐ (for Neumann) layer potentials corresponding to their solutions are classical solutions of the Stokes problems.
An Lq‐theory for weak solutions of the stokes system in exterior domains
Authors: Farwig R. , Simader C. G. , Sohr H.
Published: October 2005

We introduce a new concept for weak solutions in Lq‐spaces, 1 < q < ∞, of the Stokes system in an exterior domain Ω ⊂ ℝn, n ⩾ 2. Defining the variational formulation in the homogeneous Sobolev space \documentclass{article}\pagestyle{empty}\begin{document}$ \mathop H\limits^.{_{0}}^{1,q} (\Omega )^n = \{ u \in L_{1{\rm oc}}^q (\overline \Omega )^n;\nabla u \in L^q (\Omega )^{n^2 },u\left| {_{\partial \Omega } = 0} \right.\},$\end{document} we prove existence and uniqueness of weak solutions for an arbitrary external force and a prescribed divergence g = div u. On the other hand, solutions in the sense of distributions which are defined by taking test functions only in C(Ω)n are not unique if q > n/(n−1). In this case, a hidden boundary condition related to the force exerted on the body may be imposed to single out a unique solution.
The existence of solutions of a general boundary value problem for the divergence
Authors: Schwarz G.
Published: October 2005

This paper is concerned with the question of necessary and sufficient conditions to find a vector field V∈ Γ(TM) solving the equation div V = Φ under inhomogeneous boundary conditions V|∂M = Z|∂M with Z∈ Γ (TM) An existence and regularity result is given for an arbitrary Riemannian manifold with boundary, M. The proof is based on the Hodge theory of differential forms.
Bifurcations of strongly non‐linear self‐excited oscillations
Authors: Doelman Arjen , Verhulst Ferdinand
Published: October 2005

Perturbation of a single‐degree‐of‐freedom conservative oscillator leads to the emergence and vanishing of periodic solutions and to various types of self‐excited oscillations. Using techniques from dynamical systems theory, in particular a certain Poincaré map, we establish the presence of Hopf bifurcations, various types of homoclinic bifurcations and saddle‐node bifurcations of the associated Poincaré map. The corresponding bifurcation sets in parameter space are computed explicitly by perturbation methods. The theory is applied to the generalized van der Pol and the generalized Rayleigh oscillator, and to the case of a non‐linear spring attached to a conveyor belt.
An elementary proof of the exponential blow‐up for semi‐linear wave equations
Authors: Takamura Hiroyuki
Published: October 2005

This paper deals with the upper bound of the life span of classical solutions to □u = ∣u∣p, u∣t = 0 = εφ(x), ut∣t=0 = εψ(x) with the critical power of p in two or three space dimensions. Zhou has proved that the rate of the upper bound of this life span is exp(ε−p(p−1)). But his proof, especially the two‐dimensional case, requires many properties of special functions. Here we shall give simple proofs in each space dimension which are produced by pointwise estimates of the fundamental solution of □. We claim that both proofs are done in almost the same way.
Global existence, uniqueness and asymptotic behaviour of solutions of the Wigner–Poisson and Schrödinger‐Poisson systems
Authors: Illner Reinhard , Zweifel Paul F. , Lange Horst
Published: October 2005

We prove global existence and uniqueness of classical solutions of the Wigner–Poisson and Schrödinger–Poisson systems of equations for both repulsive and attractive potentials. In the repulsive case, we prove decay estimates for the particle density, the potential and the solutions.
Stability and instability in adiabatic shearing motions of incompressible fluids
Authors: Jiang Song
Published: October 2005

We investigate the effect of temperature dependence of the viscosity on the stability of the adiabatic shearing flows of an incompressible Newtonian viscous fluid between two parallel plates. When the viscosity strongly decreases with temperature, the shearing flow caused by a steady motion of the upper plate (steady shearing) becomes unstable, while the shearing flow caused by a time‐dependent body force is found to be stable.
The existence of global in space variables solution for non‐linear subelliptic equation of floating water
Authors: Sidz Leszek
Published: October 2005

The existence of global in space variables solutions for a class of non‐linear subelliptic evolution operators is proved. A Cauchy problem and an initial‐boundary value problem are considered using the contraction theorem and Galerkin methods.
On a mathematical model for hot carrier injection in semiconductors
Authors: Abdallah Naoufel Ben , Degond Pierre , Schmeiser Christian
Published: October 2005

We study a collisionless transport model for electrons in a semiconductor, and we perform an asymptotic analysis for low temperatures or large applied biases. We derive analytic relations for the built‐in potential and for the current which flows through the structure.
Non‐classical interface problems for piecewise homogeneous anisotropic elastic bodies
Authors: Jentsch Lothar , Natroshvili David
Published: October 2005

Two non‐classical model interface problems for piecewise homogeneous anisotropic bodies are studied. In both problems on the contact surface jumps of the normal components of displacement and stress vectors are given. In addition, in the first problem (Problem H) the tangent components of the displacement vectors are given from both sides of the contact surface, while in the second one (Problem G) the tangent components of the stress vectors are prescribed on the same surface. The existence and uniqueness theorems are proved by means of the boundary integral equation method, and representations of solutions by single layer potentials are established. In the investigation the general approach of regularization of the first kind of integral equations is worked out for the case of two‐dimensional closed smooth manifolds. An equivalent global regularizer operator is constructed explicitly in the form of a singular integro‐differential operator.
Physical model, theoretical aspects and applications of the flight of a ball in the atmosphere. Part III: Theory in the case of vertical angular frequency and in the general spin‐case
Authors: Fuchs P. M.
Published: October 2005

If a ball is viewed as a rigid body, its flight in the atmosphere can be described by six ordinary differential equations, which has been derived in the first part of this paper.

In this following third part, some further theoretical aspects in the case of vertical angular frequency will be pointed out using an unknown transformation of the original independent variable, i.e. the time, as indicated in Part II.

Last, but not least, the general case of angular frequency is to be treated. A rough qualitative discussion of the solutions is given as well as—if the equations are viewed as a three‐dimensional dynamical system—the unique stable equilibrium, which depends on the spin. This equilibrium turns out to be globally attractive, which can be proved by the construction of a suitable Ljapunov function. Then, the ball flight system can be transformed into a fourth‐order scalar differential equation.
Global existence and blow‐up for a system of heat equations with non‐linear boundary conditions
Authors: Deng Keng
Published: October 2005

In this paper, we consider non‐negative solutions of magnified image

We prove that if pq ⩽ 1 every solution remains bounded, while all solutions blow up in a finite time if pq > 1. We also show that if p,q > 1, then blow‐up can only occur on the boundary.
The free boundary problem of a semiconductor in thermal equilibrium
Authors: Jüngel Ansgar
Published: October 2005

The quasi‐hydrodynamic model for semiconductor devices in thermal equilibrium admits in general solutions for which the electron or hole density vanish. These sets are called vacuum sets. In this paper estimates on the vacuum sets and a first step in the regularity of the free boundary of these sets are presented. Numerical examples, including error estimates for linear finite elements, for the devices diode, bipolar transistor and thyristor indicate that the free boundary is more regular than theoretically predicted.
Integral equations for the diffraction problems in the wedge
Authors: Podipenko Ju. K.
Published: October 2005

In the present paper we investigated the boundary value problems appearing in the study of diffraction of acoustical or electromagnetic waves on arbitrary bounded body contained within the wedge. The potential theory has been developed making it possible to reduce the boundary value problems to Fredholm integral equations on the body's boundary. We prove existence and uniqueness of solutions for these integral equations and the boundary value problems.

For some other types of domains with infinite boundaries similar problems have been studied in [4, 6–8, 12–14, 19, 20, 22, 23, 25–28].
Stability of semilinear ill‐posed problems with a prescribed energy bound
Authors: Lyashenko A. A.
Published: October 2005

In the present paper we discuss the stability of semilinear problems of the form Aαu + Gα(u) = ƒ under assumption of an a priori bound for an energy functional Eα(u) ⩽ E, where α is a parameter in a metric space M. Following [11] the problem Aαu + Gα(u) = ƒ, Eα(u) ⩽ E is called stable in a Hilbert space H at a point α ϵ M if for any ƒϵH, E, ϵ > 0 there exists δ > 0 such that for any functions uα1, uα2 satisfying Aαjuαj + Gαj(uαj) = ƒαj, Eαj(uαj) ⩽ E, j = 1,2 we have ‖uα1 − uα2H ⩽ ϵ provided ρM(αj, α) ⩽ δ, ‖ƒαj − ƒ‖H ⩽ δ, j = 1,2. In the present paper we obtain stability conditions for the problem Aαu + Gα(u) = ƒ, Eα(u) ⩽ E.
Hyperbolicity of the hydrodynamic model of plasmas under the quasi‐neutrality hypothesis
Authors: Cordier Stéphane
Published: October 2005

Collisionless and quasi‐neutral hydrodynamic model of plasmas consisting of electrons and several species of ions are investigated. When two species of ions are considered, the hyperbolicity of the system of transport equations obtained in the quasi‐neutrality limit leads to a restriction on the magnitude of the admissible relative velocities.
Global wellposedness for quasi‐linear symmetric hyperbolic systems with regularized coefficients
Authors: Ascoli Davide
Published: October 2005

Following the abstract setting of [8] and using the global results of [2], global wellposedness and regularity results are proved for the solutions of quasi‐linear symmetric hyperbolic systems with bounded coefficients which are regularized by a convolution in the space variables with a regularizing function. In the case of unbounded regularized coefficients, local existence of classical solutions is proved, as well as uniqueness and regularity of (not necessarily existing) global weak solutions with initial value in a Sobolev space. As the regularizing function tends to Dirac's δ, local‐in‐time convergence to the classical solution of the non‐regularized problem is proved.
On the stationary quasi‐Newtonian flow obeying a power‐law
Authors: Blavier Eric , Mikelić Andro
Published: October 2005

We investigate in this paper existence of a weak solution for a stationary incompressible Navier‐Stokes system with non‐linear viscosity and with non‐homogeneous boundary conditions for velocity on the boundary. Our concern is with the viscosity obeying the power‐law dependence ν(ξ) = ∣Tr(ξξ*)∣r/2−1, r < 2, on shear stress ξ. It is corresponding to most quasi‐Newtonian flows with injection on the boundary. Since for r ⩽ 2 the inertial term precludes any a priori estimate in general, we suppose the Reynolds number is not too large. Using the specific algebraic structure of the Navier‐Stokes system we prove existence of at least one approximate solution. The constructed approximate solution turns out to be uniformly bounded in W1,r (Omega;)n and using monotonicity and compactness we successfully pass to the limit for r ≥ 3n/(n + 2). For 3n/(n + 2) > r > 2n/(n + 2) our construction gives existence of at least one very weak solution. Furthermore, for r ≥ 3n/(n + 2) we prove that all weak solutions lying in the ball in W of radius smaller than critical are equal. Finally, we obtain an existence result for the flow through a thin slab.
Periodic solutions for differential equations of order three, with application to heat‐flux induced convection
Authors: Néel M. C. , Lyubimov D.
Published: October 2005

In this paper we show the existence of periodic solutions for a class of non‐linear regular vector fields of ℝ3 admitting the trivial solution and depending on a real parameter μ. Two main assumptions lead to this conclusion: first, the right hand‐side of each vector field anticommutes with a reflection. Then, its linear part admits the eigenvalue zero for all variations of μ, and takes the form of a three‐dimensional Jordan block at μ = 0. This result allows the description of the bidimensional stationary patterns induced by a uniform heat‐flux imposed on the boundaries of an infinite porous layer, saturated by a fluid. Indeed, when the filtration Rayleigh number comes close to its critical value, the field of seepage velocity and the field of temperature can be related to a partial differential equation, which admits a three‐dimensional centre manifold. The existence of convective patterns follows. Their length depends on the filtration Rayleigh number, and tends towards infinity when this parameter comes close to its critical value (from above).
On Sommerfeld's half‐plane problem for the equations of linear thermoelasticity
Authors: Erbe Claudia
Published: October 2005

The Sommerfeld screen problem—well known by many publications studying the several mathematical and physical aspects—is generalized to the linear thermoelastic equations. We derive representation formulas of the solution from the data in the whole plane containing the screen. The corresponding boundary integral equations of Wiener‐Hopf type are presented and we obtain important information concerning the factorization of the Wiener‐Hopf operators.
Molecular architecture of the neuromuscular junction
Authors: Hughes Benjamin W. , Kusner Linda L. , Kaminski Henry J.
Published: October 2005

The neuromuscular junction (NMJ) is a complex structure that serves to efficiently communicate the electrical impulse from the motor neuron to the skeletal muscle to signal contraction. Over the last 200 years, technological advances in microscopy allowed visualization of the existence of a gap between the motor neuron and skeletal muscle that necessitated the existence of a messenger, which proved to be acetylcholine. Ultrastructural analysis identified vesicles in the presynaptic nerve terminal, which provided a beautiful structural correlate for the quantal nature of neuromuscular transmission, and the imaging of synaptic folds on the muscle surface demonstrated that specializations of the underlying protein scaffold were required. Molecular analysis in the last 20 years has confirmed the preferential expression of synaptic proteins, which is guided by a precise developmental program and maintained by signals from nerve. Although often overlooked, the Schwann cell that caps the NMJ and the basal lamina is proving to be critical in maintenance of the junction. Genetic and autoimmune disorders are known that compromise neuromuscular transmission and provide further insights into the complexities of NMJ function as well as the subtle differences that exist among NMJ that may underlie the differential susceptibility of muscle groups to neuromuscular transmission diseases. In this review we summarize the synaptic physiology, architecture, and variations in synaptic structure among muscle types. The important roles of specific signaling pathways involved in NMJ development and acetylcholine receptor (AChR) clustering are reviewed. Finally, genetic and autoimmune disorders and their effects on NMJ architecture and neuromuscular transmission are examined. Muscle Nerve, 2005
The role of neurotrophins in muscle under physiological and pathological conditions
Authors: Chevrel Guillaume , Hohlfeld Reinhard , Sendtner Michael
Published: October 2005

This review summarizes the various effects of neurotrophins in skeletal muscle and how these proteins act as potential regulators of development, maintenance, function, and regeneration of skeletal muscle fibers. Increasing evidence suggests that this family of neurotrophic factors not only modulates survival and function of innervating motoneurons and proprioceptive neurons but also development and differentiation of myoblasts and muscle fibers. Neurotrophins and neurotrophin receptors play a role in the coordination of muscle innervation and functional differentiation of neuromuscular junctions. However, neurotrophin receptors are also expressed in differentiating muscle cells, in particular at early developmental stages in myoblasts before they fuse. In adults with pathological conditions such as human degenerative and inflammatory muscle disorders, variations of neurotrophin expression are found, but the role of neurotrophins under such conditions is still not clear. The goal of this review is to provide a basis for a better understanding and future studies on the role of these factors under such pathological conditions and for treatment of human muscle diseases. Muscle Nerve, 2005
Bladder dysfunction in patients with cauda equina lesions
Authors: Podnar Simon , Tršinar Bojan , Vodušek David B.
Published: October 2005

Aims

Data on lower urinary tract (LUT) function obtained in larger, systematically studied populations of patients with cauda equina lesions are limited. We report urinary function in 65 patients with chronic lesions.

Methods

A urinary function questionnaire was used, and neurological examination, quantitative electromyography (EMG) of the external anal sphincter (EAS) muscles, EMG assessment of the sacral reflex, and conventional urodynamic measurements were performed.

Results

Severe LUT dysfunction was found in 14%/15%, moderate in 27%/46%, and mild in 46%/39% men/women. Urinary symptoms interfered with daily life in 88%/92% and sexual life in 72%/67% of sexually active men/women. Symptoms of disturbed bladder emptying were the most common (95%/92% men/women), followed by urinary incontinence (56%/71%) and symptoms of overactive bladder (40%/56%). Perianal sensation was abnormal in 96%, EMG of the EAS muscle in 88%, and sacral reflex in 84% of patients. In 40%/17% men/women, a postvoid residual ( >100 ml) was found. On filling cystometry overactive bladder was found in 21%/0%, reduced detrusor capacity in 9%/15%, and during voiding phase an acontractile detrusor or detrusor underactivity were found in 59%/85% men/women. Using multiple linear regression analysis, perianal sensory loss (P = 0.0001) and female gender (P < 0.02) had a significant positive effect on urinary incontinence score.

Conclusions

Our study demonstrated significant LUT dysfunction, which disturbed the life of the majority of patients with chronic lesions of the cauda equina. Due to poor correlation between patients' symptoms and urodynamic findings cystometric surveillance is proposed in all patients with significant cauda equina lesions. Neurourol. Urodynam. © 2005 Wiley‐Liss, Inc.
Urinary incontinence and voiding dysfunction after radical retropubic prostatectomy (prospective urodynamic study)
Authors: Majoros Attila , Bach Dietmar , Keszthelyi Attila , Hamvas Antal , Romics Imre
Published: October 2005

Aims

During this prospective study we analyzed the effects of radical retropubic prostatectomy (RRP) on bladder and sphincter function by comparing preoperative and postoperative urodynamic data. The aim of the study was to determine the reason for urinary incontinence after RRP and explain why one group of patients will be immediately continent after catheter removal, while others need some time to reach complete continence.

Methods

Urodynamic examination was performed in 63 patients 3–7 days before and 2 months after surgery.

Results

Forty‐three (68.2%) and 53 (84.1%) patients regained continence at 2 and 9 months following RRP, respectively. Ten patients (15.9%) were immediately continent after catheter removal. Urodynamic stress incontinence was detected in 18 (28.6%), and detrusor overactivity incontinence in 2 (3.2%) patients 2 months after surgery. The amplitude of preoperative maximal voluntary sphincteric contractions was significantly higher in the postoperative continent group (125 vs. 96.5 cmH2O, P < 0.0001). The patients who were immediately continent following catheter removal had no lower urinary tract symptoms (LUTS) and urodynamic abnormality preoperatively, and they had significantly higher preoperative and postoperative maximum urethral closure pressure (at rest and during voluntary sphincter contraction) than those who became continent later on.

Conclusions

These data suggest that the main cause of incontinence after RRP is sphincteric weakness. In the continent group, those who became immediately continent had significantly higher maximum urethral closure pressure values at rest and at voluntary sphincteric contraction even before the surgery. Neurourol. Urodynam. © 2005 Wiley‐Liss, Inc.
Detection of neurogenic detrusor contractions from the activity of the external anal sphincter in cat and human
Authors: Wenzel Brian J. , Boggs Joseph W. , Gustafson Kenneth J. , Creasey Graham H. , Grill Warren M.
Published: October 2005

Aims

Individuals with spinal cord injury or neurological disorders may develop bladder contractions at low volumes (neurogenic detrusor overactivity), which can lead to significant health problems. Present devices can inhibit unwanted contractions through continuous electrical stimulation of sensory nerves, but do not enable conditional stimulation only at the onset of bladder contractions. The objectives of this study were to determine the relationship between the electrical activity of external anal sphincter (EAS) and bladder pressure during neurogenic detrusor contractions and to determine whether EAS activity could be used to detect the onset of bladder contractions.

Methods

Bladder pressure and EAS electromyogram (EMG) were recorded in nine adult male cats. Retrospective clinical data consisting of bladder pressure and EAS EMG from 41 spinal cord injured individuals with neurogenic detrusor overactivity were analyzed. A CUSUM algorithm was used to detect the onset of bladder contractions from the EAS EMG.

Results

EAS EMG activity increased at the onset of bladder contractions in six cats (dyssynergic) and decreased (synergic) in three cats. The onset of bladder contractions was detected within 3 sec of the start of the contraction for both the synergic and dyssynergic data sets. The onset of bladder contractions was detected within 1 sec of the start of the bladder contraction for both synergic and dyssynergic human subjects.

Conclusions

Recordings of the EAS EMG can be used to detect robustly the onset of neurogenic detrusor contractions. The EAS EMG is a suitable signal to control closed‐loop inhibitory electrical stimulation to maintain urinary continence. Neurourol. Urdynam. © 2005 Wiley‐Liss, Inc.
A class of difference ABS‐type algorithms for a nonlinear system of equations
Authors: Spedicato E. , Chen Z. , Deng N.
Published: October 2005

In this paper we give a class of algorithms for solving nonlinear algebraic equations using difference approximations of derivatives. The class is a modification of the original ABS class with the advantage of requiring less function evaluations. Special cases include the methods of Brown and Brent and the discretized Newton method, which is formulated in a way requiring fewer function evaluations per iteration.
A simpler GMRES
Authors: Walker Homer F. , Zhou Lu
Published: October 2005

The generalized minimal residual (GMRES) method is widely used for solving very large, nonsymmetric linear systems, particularly those that arise through discretization of continuous mathematical models in science and engineering. By shifting the Arnoldi process to begin with Ar0 instead of r0, we obtain simpler Gram–Schmidt and Householder implementations of the GMRES method that do not require upper Hessenberg factorization. The Gram–Schmidt implementation also maintains the residual vector at each iteration, which allows cheaper restarts of GMRES(m) and may otherwise be useful.