bluuebunny/crossref_metadata_2025_split huggingface dataset:
Fractional Photothermolysis: A New Concept for Cutaneous Remodeling Using Microscopic Patterns of Thermal Injury
Authors: Manstein Dieter , Herron G. Scott , Sink R. Kehl , Tanner Heather , Anderson R. Rox 
Published: June 2004

AbstractBackground and ObjectivesWe introduce and clinically examine a new concept of skin treatment called fractional photothermolysis (FP), achieved by applying an array of microscopic treatment zones (MTZ) of thermal injury to the skin.Study Design/Materials and MethodsTwo prototype devices emitting at 1.5 μm wavelength provided a pattern of micro‐exposures with variable MTZ density. Effects of different MTZ densities were tested on the forearms of 15 subjects. Clinical effects and histology were assessed up to 3 months after exposure. Treatment of photoaged skin on the periorbital area in an additional 30 subjects receiving four treatments over a period of 2–3 weeks was also tested. Tissue shrinkage and clinical effects were assessed up to 3 months after treatment.ResultsPattern densities with spacing of 250 μm or more were well tolerated. Typical MTZ had a diameter of 100 μm and penetrated 300 μm into the skin. Reepithelialization was complete within 1 day. Clinical effects were assessed over a 3‐month period. Histology at 3 months revealed enhanced undulating rete ridges and increased mucin deposition within the superficial dermis. Periorbital treatments were well tolerated with minimal erythema and edema. Linear shrinkage of 2.1% was measured 3 months after the last treatment. The wrinkle score improved 18% (P<0.001) 3 months after the last treatment.ConclusionsFP is a new concept for skin restoration treatment. Safety and efficacy were demonstrated with a prototype device. Further clinical studies are necessary to refine the optimum parameters and to explore further dermatological applications. Lasers Surg. Med. 34:426–438, 2004. © 2004 Wiley‐Liss, Inc.
Laryngeal morphometry with a new laser ‘clip on’ device
Authors: Schade Goetz , Leuwer Rudolf , Kraas Mathias , Rassow Bernhard , Hess Markus M. 
Published: June 2004

AbstractBackground and ObjectivesQualitative laryngoscopic investigations belong to diagnostic routine in laryngology. Nevertheless, quantitative morphometric measurements of intralaryngeal structures have been difficult by now.Study Design/Material and MethodsThe development of a two‐point‐light projection method for endolaryngeal measurements that works with a double reflecting mirror and green laser light is shown.ResultsThe laser beams that have a distance of exactly 2 mm are very well visible at the surface of laryngeal structures. The technique can be used during a routine videoendoscopic examination.ConclusionIn our opinion this method enables accurate quantitative morphological measurement within the larynx that could be used even in clinical routine. The two‐point light projection technique helps to reduce former limitations of endoscopic investigations. Lasers Surg. Med. 34:363–367, 2004. © 2004 Wiley‐Liss, Inc.
Clinical evaluation of enhanced nonablative skin rejuvenation using a combination of a 532 and a 1,064 nm laser
Authors: Tan Mei‐Heng , Dover Jeffrey S. , Hsu Te‐Shao , Arndt Kenneth A. , Stewart Brigitte 
Published: June 2004

AbstractBackground and ObjectivesImprovements in the physical signs of photoaging can be achieved by non‐invasive laser resurfacing procedures. To evaluate the effectiveness and safety of the Nd:YAG 1,064 nm and KTP 532 nm lasers for non‐invasive skin rejuvenation.Study Design/Patients and MethodsSubjects requesting non‐invasive skin rejuvenation underwent two treatments with the 532 nm laser to one side of the face and with both lasers to the other side, followed by three treatments with the 1,064 nm laser to both sides. Skin characteristics were evaluated before, during, and up to 4 months after treatment.ResultsA >25% improvement in overall skin condition was observed for >30% of subjects at the 1 month follow‐up and >40% of subjects at the 4 month follow‐up. The greatest improvements were observed for visual dryness, roughness, and uneven pigmentation. No adverse events were reported. There was a trend for greater improvement in patients who received more 1,064 nm treatments but this was not statistically significant.ConclusionsThe 532 nm KTP and 1,064 nm Nd: YAG lasers can be effectively and safely used for non‐invasive skin rejuvenation. Lasers Surg. Med. 34:439–445, 2004. © 2004 Wiley‐Liss, Inc.
Electrically Conducting Gels Formed From Polyaniline/Ethylcellulose/m‐Cresol Ternary Solutions
Authors: González Ignacio , Vecino Mónica , Muñoz M. Eugenia , Santamaría Anton , Pomposo J. Adolfo 
Published: June 2004

AbstractSummary: Polyaniline doped with camphorsulfonic acid (PANI‐CSA) and ethylcellulose (EC), constitutes the basis of the investigated binary PANI(CSA)0.5/m‐cresol and ternary PANI(CSA)0.5/EC/m‐cresol solutions. Ternary solutions give rise to gels with a lower elastic modulus and electrical conductivity than binary PANI(CSA)0.5/m‐cresol gels. However, the dimensional stability is considerably improved, since warping observed in binary gels is eliminated or lessened. These results are explained considering the role played by ethylcellulose, which interacts with the hydroxyl group of m‐cresol, skimping PANI(CSA)0.5/m‐cresol specific interactions and retarding solvent evaporation.Electrical conductivity of binary (▴) and ternary (•) gels as a function of m‐cresol content. The arrow indicates that warping is observed below this solvent level.magnified imageElectrical conductivity of binary (▴) and ternary (•) gels as a function of m‐cresol content. The arrow indicates that warping is observed below this solvent level.
Modified technique of ureteroureterostomy in rat kidney transplantation
Authors: Pietsch Alexander , Nett Philipp C. , Sollinger Hans W. , Hullett Debra A. 
Published: June 2004

AbstractDifferent strain combinations of rats are available to study immunological and transplant‐related problems in the models of kidney transplantation. Although numerous modifications of surgical techniques for ureteric reconstruction are evaluated in order to reduce complications and to extend long‐term survival, ureteric complications still occur frequently, especially when the difference in diameter of both donor and host ureters is disproportionate. Instead of using the current nonsplinted ureteroureterostomy (method A), a versatile and rapid technical modification (method B) was developed to perform reconstruction of ureters with disproportionate diameters. The overall incidence of ureteric complications was 80% (8/10) using method A, whereas this rate was significantly reduced to 15% (3/20) using method B (P < 0.001). Our modification proves the feasibility of nonsplinted ureteroureterostomy in a technical, highly demanding rat model of kidney transplantation with an acceptable rate of ureteric complication, considering the disproportionate difference in diameter between the host and donor ureters. © 2004 Wiley‐Liss, Inc.
Oxidative stress–associated mitochondrial dysfunction in corticosteroid‐treated muscle cells
Authors: Oshima Yasushi , Kuroda Yukiko , Kunishige Makoto , Matsumoto Toshio , Mitsui Takao 
Published: June 2004

AbstractWe analyzed the effects of corticosteroid on mitochondrial membrane potentials (ΔΨm), generation of reactive oxygen species (ROS), and apoptosis in a human rhabdomyosarcoma cell line, RD, and a dopaminergic neuroblastoma cell line, SH‐SY5Y. The cell lines were cultured in the presence or absence of dexamethasone and superoxide dismutase (SOD) for up to 1 week. Dexamethasone treatment increased ΔΨm, ROS generation, and apoptosis in proliferating RD cells. Treatment with SOD attenuated ROS generation and apoptosis, but not ΔΨm. The increase in ΔΨm seemed to be the primary effect of dexamethasone on proliferating RD cells, which is probably mediated by mitochondrial transcription. In differentiated RD cells, but not differentiated SH‐SY5Y cells, dexamethasone treatment showed a delayed effect of interfering with the ΔΨm and increasing ROS generation and apoptosis. Since these changes disappeared in the presence of SOD, dexamethasone primarily induced ROS generation, resulting in apoptosis. We speculate that this mechanism provides the basis of a pathophysiological model of corticosteroid myopathy. Muscle Nerve 30:49–54,2004
Stochastic optimization for the ruin probability
Authors: Schäl Manfred 
Published: June 2004

AbstractThe Cramér‐Lundberg insurance model is studied where the risk process can be controlled by reinsurance and by investment in a financial market. The performance criterion is the ruin probability. The problem can be imbedded in the framework of discrete‐time stochastic dynamic programming. Basic tools are the Howard improvement and the verification theorem. Explicit conditions are obtained for the optimality of employing no reinsurance and of not investing in the market.
Combining landmark and intensity driven registrations
Authors: Fischer Bernd , Modersitzki Jan 
Published: June 2004

AbstractOne of the challenging tasks in today image processing is image registration. Image registration is inevitable whenever images taken for example at different times or from different perspectives need to be compared or to be integrated. Typically, the location of corresponding points in the different views of one object or even of different objects is distorted. For example, motion or different properties of the underlying optical systems (MR, CT) are responsible for the distortion. Thus, a basic problem is to find a meaningful spatial transformation of a given image, such that the transformed image becomes similar to a given second one. Typically, the transformation is computed by minimizing a suitable similarity measure. For many applications it is also desirable to guide the registration by additional information, like the locations of outstanding points. In this note, be present a general variational based approach for image registration which allows the choice of a user supplied similarity measure and a user supplied regularizer as well as the integration of external knowledge, like, for example, the location of outstanding points.
3D‐Flow structures behind a circular cylinder with hemispherical head geometry
Authors: Leder A. , Grebin U. , Hassel E. , Kashkoul Y. , Ackl A. 
Published: June 2004

AbstractAn experimental investigation of the flow around a finite circular cylinder mounted on a flat plate, see fig. 1, is reported. The aspect ratio L/D (with length L and diameter D) of the cylinder model is 2.0. The focus of this study is toward examining the complex separated flow structures and wake properties. Velocity and turbulence measurements have been carried out with a three component Laser Doppler anemometer (LDA) at the Reynolds number ReD = 2.0 · 105. The experimental results show complex 3D fluid motions in the separated flow region. They are induced by the superposition of three main vortical flows.
An adaptive Lagrange‐Galerkin method for the shallow‐water equations on the sphere
Authors: Läuter Matthias 
Published: June 2004

AbstractThe shallow‐water equations on the sphere are compressible Navier‐Stokes equations that describe hydrostatic atmospheric dynamics. An adaptive Lagrange‐Galerkin method is applied on the spherical domain to develop a simplified global atmospheric model. Computational results show the experimental convergence of this numerical method.
Homogenization of cellular structures for soft tissue modelling
Authors: Rohan Eduard 
Published: June 2004

AbstractThe aim of the paper is to show how the method of homogenization can be applied in modelling of soft tissue undergoing large deformation. Simplified microstructures are considered, which consist of hyperelastic porous matrix and periodic array of fluid‐filled cells. At the microscopic level diffusion processes are described by the Darcy law, permeability of the cellular membrane is introduced. Although at the macroscopic scale the tissue is incompressible, the flow inside microscopic volumes induces viscous relaxation effects. The homogenized problem is formulated.
Simulating Prosthetic Gait ‐ Lessons to Learn
Authors: Brugger P. , Schmiedmayer H.‐B. 
Published: June 2004

AbstractModern computer assisted above knee prostheses currently available on the market (e.g. C‐Leg from Otto‐Bock) allow the patients to choose their walking speed freely during level walking. Due to energy reasons it is only possible to change the passive mechanical characteristics of the prosthetic limb but no active actuators can be used to influence the knee joint movement. The control strategies for level walking act on the damping of the knee joint during swing phase of gait. During walking down ramps or descending stairs the control strategies are switched off in current designs. Based on a measured reference kinematics it should be possible to study the influence and behaving of technical devices in combination with the whole body biomechanical system. For this purpose we use a combined inverse‐forward‐dynamics approach. Kinematics parameters that are not critical in the inverse‐dynamics approach (leading to physiological reasonable forces and moments) and that are not influenced by the other parameters in the model are prescribed as in the classical inverse‐dynamics approach. To follow the other kinematics parameters (joint‐angles) control elements are used where the associated joint‐moments are determined by the goal trajectory and physiological boundary conditions. The so called “controlled joints” of the model and the applied technical device (prosthesis) are formulated as a forward‐dynamics system. In contrast to experimental studies a simulation study offers the advantage, that parameters can be varied in a wide range. Different ramp and stair inclinations can be implemented and different control strategies can be tested without any risk for the patient. The disadvantage lies in the fact, that there are only few reference sets for the kinematics of real patients. The modification of a reference kinematics for different situations (level walking, ramp or stair descent) is a big challenge and needs further investigation. On the other hand the combined inverse‐forward‐dynamics approach with its well balanced simplicity and complexity offers a flexible tool to reach this aim. This approach can also be used to investigate the interaction of the biomechanical system with other technical systems like sports equipment.
The optimal elbow angle for acrobatics ‐ stability analysis of the elbow with a load
Authors: Giesl Peter 
Published: June 2004

AbstractWe consider a human elbow with a load and study the existence and stability of equilibrium positions without the use of reflexes. We observe that for each elbow angle there is a critical mass above which the equilibrium becomes unstable. We determine the optimal elbow angle, i.e., the angle such that the corresponding critical mass is as high as possible.
Stability Structure for Lattice Boltzmann Equations: Some Computational Results
Authors: Banda M.K. , Yong W.‐A. , Klar A. 
Published: June 2004

AbstractThe Lattice Boltzmann equations are usually constructed to satisfy physical requirements like Galilean invariance and isotropy as well as to possess a velocity‐independent pressure, no compressible effects, just to mention a few. In this paper, a stability criterion for such constructions is introduced and is used to derive a new relation of the parameters in a parametrized 2‐dimensional 9‐velocity model.
Analysis of lattice Boltzmann boundary conditions
Authors: Junk M. , Yang Z. 
Published: June 2004

AbstractThe correct implementation of Navier‐Stokes boundary conditions in the framework of lattice Boltzmann schemes is complicated by the non‐availability of analytical methods to assess the consistency of such discretizations. To close this gap, we propose a simple direct asymptotic analysis which is readily applicable to finite difference discretizations of initial boundary value problems in general and to lattice Boltzmann methods in particular. Results of the analysis applied to the classical lattice Boltzmann scheme with bounce back boundary condition are reported.
Mechanical Modelling of Drill‐Strings
Authors: Kreuzer E. , Struck H. 
Published: June 2004

AbstractVibrations in long torsional strings result in spatio‐temporal dynamics. These vibrations disturb the accuracy of the drilling process and may cause damage due to fatigue. The high costs of drillings are the main motivation for the suppression of vibrations of the drill–string. In this paper a model for the drill string is proposed. In order to describe the dynamics of the drill–string appropriately but as simple as possible the model has to comprise bending vibrations, self–excited torsional vibrations as well as the coupling between them. The aim of the model with only few degrees of freedom is the development of an optimal control technique for the active damping of drill–string vibrations. The string is modeled as a one–dimensional continuum. Two sets of variables are proposed for the formulation of kinematics: one is suitable for the description of the kinetic energy the other for the description of the elastic energy. Differential geometry yield equations which express one sets of variables in terms of the other. These equations can be linearised. In order to justify the linearisation, an analysis of the parameters is made. Since the Lagrangian can be written in a more compact form than the equations of motion, the Lagrangian is investigated: All variables are normalised and the order of magnitude of the terms are compared. The simplified Lagrangian yields the equations of motion which are solved approximately using Galerkin's method. Forces due to the interaction between the fluid and the structure are considered as well as those due to contact with the borehole.
Stability analysis of the servohydraulic equations with linear state feedback and harmonic reference signal
Authors: Manhartsgruber Bernhard 
Published: June 2004

AbstractThe servohydraulic equations describe the dynamic behaviour of a hydrostatic drive featuring a servo‐valve and a hydraulic cylinder. Under the assumptions of constant supply pressures, a rigid support of the cylinder, and a rigid mass attached to the piston, the evolution of cylinder pressures as well as piston position and velocity is governed by a 4th order non‐linear ordinary differential equation. The servo valve is assumed to be much faster than the dynamics of the mass‐cylinder system. Thus, the valve dynamics is neglected. Adding a feedback control law makes up the servohydraulic equations.These equations are partially singularly perturbed. The perturbation parameter is associated with fluid compressibility and the reduced system corresponds to the case of an incompressible fluid. This paper deals with the stability analysis of periodic orbits arising in the case of harmonic reference position trajectories. Geometric singular perturbation theory is used to generate stability charts. Numerical computations verify the analytical results. For a given set of hydraulic system parameters, the stability of periodic orbits depends on controller gains as well as on the amplitude and frequency of the reference signal.
Moderately large flexural vibrations of sandwich plates with thick layers
Authors: Adam Christoph 
Published: June 2004

AbstractIn this paper moderately large amplitude vibrations of a polygonally shaped composite plate with thick layers are analyzed. Three homogeneous and isotropic layers with a common Poisson's ratio are perfectly bonded, and their arbitrary thickness and material properties are symmetrically disposed about the middle plane. Mindlin‐Reissner kinematic assumptions are implemented layerwise, and as such model both the global and local response. Geometric nonlinear effects arising from longitudinally constrained supports are taken into account by Berger's approximation of nonlinear strain‐displacement relations. The shear stress continuity across the interfaces is prescribed according to Hooke's law, and subsequently, a correspondence of this higher order problem to the simpler case of a homogenized shear‐deformable nonlinear plate with effective stiffness and hard hinged boundary conditions is found.
Length‐scale effect in dynamics of hexagonal lattice‐type plates
Authors: Cielecka Iwona , Jędrysiak Jarosław 
Published: June 2004

AbstractIn the contribution lattice‐type plates with hexagonal structure in plane 0x1x2 are analysed. The aim of the note is to apply a length‐scale model of lattice‐type periodic plates derived within the tolerance averaging method (developed for periodic composites and structures by Woźniak and Wierzbicki (2000)) to analyse vibrations of hexagonal plates. It will be shown that the derived model, taking into account the effect of the periodicity cell size on the overall plate behaviour, is represented by equations with constant coefficients in the form similar to equations for isotropic cases.
A note on the nonlinear modeling of piezoelectric rods
Authors: Gausmann Rainer , Seemann Wolfgang 
Published: June 2004

AbstractPiezoceramic materials are usually calculated using linear constitutive equations if the exciting electric field is small. If the structure is excited near a resonance frequency the assumption of a linear material becomes invalid. Therefore nonlinear constitutive equations have to be used if the super harmonics in the measured velocity signals should be modeled. In this paper nonlinear constitutive equations are derived from the electric enthalpy density to describe the longitudinal oscillations of a piezoceramic rod. The kinetic energy considers the inertia effects in transversal direction so the model is not limited to the slender rod theory. With Hamilton's principle a variational principle is derived which is approximated using a Rayleigh Ritz ansatz with the first eigenfunction of the linearized system. The resulting nonlinear ODE is solved by application of the harmonic balance method. The amplitudes of displacement of the fundamental, the second and the third super harmonic oscillations are solved numerically. In a first step the results of the theoretical model are compared with measurements. The material parameters of the nonlinear constitutive equations are calculated using a parametric identification method. As a result it is shown that the theoretical model can describe the Duffing type nonlinearities found in measurements.
The Effect of Variable Eccentricity onto the Oscillations in a Coiling Process
Authors: Hammelmüller Franz , Holl Helmut J. 
Published: June 2004

AbstractThe mechanical model and the equations of motion of a rapid long‐term coiling process are presented. Additional effects are considered in the mechanical model in extension of the simple Laval‐rotor. Due to the coiled material the outer radius and the stiffness of the coiling drum varies with the rotation angle. The variable mass of the rotor has an important influence upon the oscillations of the rotor. Additionally, for the mechanical system under consideration, the resulting oscillations due to a variable eccentricity are analyzed. For the solution of the dynamic system an extended Newmark‐method is applied with a time‐step, which guarantees a converged solution. Numerical studies are performed for various parameters in order to highlight the influence of variable mass and variable eccentricity.
On the use of the Subspace Identification Method to identify Mechanical System Properties
Authors: Kompalka Andreas , Reese Stefanie 
Published: June 2004

AbstractThis contribution gives an overview about the present state of our research in the project B4 in the Collaborative Research Center 398 at the Ruhr University Bochum. The subject of the research topic is the diagnosis and localisation of discrete damage by vibration measurement with the aim of lifetime estimation. First of all, we discuss the verification of eigensystem realization algorithms for system identification. In the second part, a method for finite element model updating is investigated in view of its application for damage localization. A contribution of both methods is validated by means of a numerical example.