bluuebunny/crossref_metadata_2025_split huggingface dataset:
Central Venous Catheter Associated Infections Pathophysiology, Incidence, Clinical Diagnosis, and Prevention – A Review
Authors: Guggenbichler J. P. 
Published: January 2004

AbstractThe incidence of catheter related bloodstream infections poses a substantial burden on patient’s life’s and well‐being. Estimated 2 – 6 % of patients suffer from catheter associated bloodstream infections (BSI). Reports on mortality of these patients are up to 30 % in addition to a substantial prolongation of hospital days. The estimated cost of therapy of a BSI is approximately 10 000 € per patient.There is a definitive need for antimicrobially active medical devices for prophylaxis. Endowment of catheters with antibiotics and desinfectants have substantial limitations regarding spectrum of activity, duration of activity and clinical efficacy.The oligodynamic activity of silver has the greatest potential for prevention of catheter related infections. Various technologies in particular surface coating of these medical devices have been advocated previously with limited success. A new technology with impregnation of the entire catheter matrix with billions of nanoparticles of silver0 which results in a surface of 2000 cm2/g polyurethane (PU) has been developed.Central venous catheters manufactured according to the technology of the first and second generation have been investigated with good results of antimicrobial activity and biocompatibility. Favorable results in experimental investigations and good clinical results in controlled prospective, randomized, investigator blinded studies of the first generation silver catheter have been obtained. In 660 patients in an overall reduction of BSI of 66 % was observed. Favorable results in a postmarketing surveillance with 3000 patients were seen.The premarketing surveillance of the second generation silver‐catheter indicated an even greater reduction of catheter related BSI. In 204 patients with a mean duration of catheter placement of 9.2 days only one catheter related BSI was diagnosed. The rate of catheter colonization was <10 %. The catheter was well tolerated.A further improvement with increased antimicrobial activity was achieved by activation of silver nanoparticles in the third generation catheter: The superior results of in vitro tests and excellent biocompatibility lets us expect an additional improvement of preventive measures.The duration of antimicrobial activity has been investigated and lasts at least 370 days.The concept of impregnation of a polymer matrix and silicone can be extended to various other clinical applications e.g. Sheldon, Hickman and urologic catheters. Substantial savings in the cost of patient care through prevention of complications can be expected which is of particular importance with the disease oriented (DRG) remuneration system.
Osteogenic Response of C2C12 Cells on Thermoreversible Polymers
Authors: Uludag H. , Smith E. , McGann L. E. , Yang J. 
Published: January 2004

AbstractBone Morphogenetic Proteins (BMPs) in combination with biomaterials are being explored for clinical bone regeneration. The current biomaterials used for BMPs delivery are not specifically designed to support BMP‐induced osteogenesis. Towards this goal, we designed synthetic N‐isopropylacrylamide (NiPAM)‐based thermosensitive polymers and investigated their ability to support osteogenic transformation of pluripotent C2C12 cells. Cell attachment to the polymers was limited as compared to attachment to the plastic surfaces optimized for cell culture. Short‐term (<7 days) studies indicated relatively little cell growth on the polymer surfaces. However, C2C12 cells retained their ability to respond to BMP‐2, as determined by alkaline phosphatase (ALP) induction, when cultured on thermoreversible polymers. Some polymers supported ALP induction that was far superior (∼10‐fold) to cells grown on tissue culture surfaces. We conclude that thermosensitive polymers, although limited in their ability to support cell attachment and growth, did support the pluripotent cells' ability to be transformed under the influence of BMP‐2. The ALP induction was dependent on the compositional details of the polymers, suggesting that in vivo osteoinduction was likely to be influenced by the physicochemical properties of the polymers.
Comparison of Diamond‐Like‐Carbon and Alumina‐Oxide articulating with Polyethylene in Total Hip Arthroplasty
Authors: Taeger G. , Podleska L.E. , Schmidt B. , Ziegler M. , Nast‐Kolb D. 
Published: January 2004

AbstractTo reduce wear in joint bearings of total hip arthroplasty (THA) is the most important issue for improving long term results and implant survival. Due to low wear rates and excellent tribological features in simulator tests Diamond‐Like‐Carbon coating (DLC) of femoral balls is still discussed as an alternative articulation in THA. This clinical prospective study compares survivorship of DLC‐coated femoral heads and of Aluminia‐Oxide‐ (Al2O3) heads articulating with Polyethylene (PE).Over a period of two years 101 THA with DLC‐coated heads and PE cups (DLC‐group) and another 101 THA consisting of Al2O3 heads (Al2O3‐group) and PE cups as well were implanted. Both articulations were based on the same type of cementless hip joint prosthesis. All hips were implanted by one surgeon in consecutive series consisting of 51 Al2O3 and 101 DLC‐articulations and further 50 Al2O3. All perioperative and follow‐up data was processed with SPSS®. Survival of THA in both groups was evaluated according to Kaplan‐Meier survivorship analysis with an intervall of 90 months (range:78‐101). Qualitative surface analysis was performed in nineteen retrieved DLC‐heads which were revised for aseptic loosening using field scanning electron microscopy (FE‐SEM, XL 30 SFEG Philips, Eindoven NL).178 patients (88.2 %) were evaluated for follow‐up. Fourteen patients died meantimes (nine DLC, five Al2O3) with the implant components not revised. Ten patients (five DLC, five Al2O3) were lost to follow‐up. Both groups were comparable regarding patient age, weight and indications for THA with a normal distribution. Survivorship analysis for aseptic loosening 8.5 years following implantation resulted in a significant difference between both groups with a 54 % survival for DLC/PE compared to 88 % for Al2O3/PE bearings (p <0.001). No correlation to variables as age, gender or bodyweight could be detected. Surfaces of nineteen retrieved DLC‐heads showed numerous smallest pits of the diamond‐carbon layers in different quantity. SEM showed delamination of the carbon layer which caused excessive debris of polyethylene and in some cases even of the metallic substrate of the heads.Despite modern manufacturing technology and excellent experimental results for its tribochemical characteristics and wear, even “new” DLC‐coating of femoral heads is to be considered critically due to very high rates of clinical failure.
The ice‐fishing problem: the fundamental sloshing frequency versus geometry of holes
Authors: Kozlov Vladimir , Kuznetsov Nikolay 
Published: January 2004

AbstractWe study an eignevalue problem with a spectral parameter in a boundary condition. This problem for the Laplace equation is relevant to sloshing frequencies that describe free oscillations of an inviscid, incompressible, heavy fluid in a half‐space covered by a rigid dock with some apertures (an ice sheet with fishing holes). The dependence of the fundamental eigenvalue on holes' geometry is investigated. We give conditions on a plane region guaranteeing that the fundamental eigenvalue corresponding to this region is larger than the fundamental eigenvalue corresponding to a single circular hole. Examples of regions satisfying these conditions and having the same area as the unit disk are given. New results are also obtained for the problem with a single circular hole.On the other hand, we construct regions for which the fundamental eigenfrequency is larger than the similar frequency for the circular hole of the same area and even as large as one wishes. In the latter examples, the hole regions are either not connected or bounded by a rather complicated curves. Copyright © 2004 John Wiley & Sons, Ltd.
On the absence of eigenvalues of Maxwell and Lamé systems in exterior domains
Authors: Bauer Sebastian 
Published: January 2004

AbstractThe arguments showing non‐existence of eigensolutions to exterior‐boundary value problems associated with systems—such as the Maxwell and Lamé system—rely on showing that such solutions would have to have compact support and therefore—by a unique continuation property—cannot be non‐trivial. Here we will focus on the first part of the argument. For a class of second order elliptic systems it will be shown that L2‐solutions in exterior domains must have compact support. Both the asymptotically isotropic Maxwell system and the Lamé system with asymptotically decaying perturbations can be reduced to this class of elliptic systems. Copyright © 2004 John Wiley & Sons, Ltd.
Asymptotic and spectral properties of operator‐valued functions generated by aircraft wing model
Authors: Balakrishnan A. V. , Shubov Marianna A. 
Published: January 2004

AbstractThe present paper is devoted to the asymptotic and spectral analysis of an aircraft wing model in a subsonic air flow. The model is governed by a system of two coupled integro‐differential equations and a two parameter family of boundary conditions modelling the action of the self‐straining actuators. The differential parts of the above equations form a coupled linear hyperbolic system; the integral parts are of the convolution type. The system of equations of motion is equivalent to a single operator evolution–convolution equation in the energy space. The Laplace transform of the solution of this equation can be represented in terms of the so‐called generalized resolvent operator, which is an operator‐valued function of the spectral parameter. More precisely, the generalized resolvent is a finite‐meromorphic function on the complex plane having a branch‐cut along the negative real semi‐axis. Its poles are precisely the aeroelastic modes and the residues at these poles are the projectors on the generalized eigenspaces. The dynamics generator of the differential part of the system has been systematically studied in a series of works by the second author. This generator is a non‐selfadjoint operator in the energy space with a purely discrete spectrum. In the aforementioned series of papers, it has been shown that the set of aeroelastic modes is asymptotically close to the spectrum of the dynamics generator, that this spectrum consists of two branches, and a precise spectral asymptotics with respect to the eigenvalue number has been derived. The asymptotical approximations for the mode shapes have also been obtained. It has also been proven that the set of the generalized eigenvectors of the dynamics generator forms a Riesz basis in the energy space. In the present paper, we consider the entire integro‐differential system which governs the model. Namely, we investigate the properties of the integral convolution‐type part of the original system. We show, in particular, that the set of poles of the adjoint generalized resolvent is asymptotically close to the discrete spectrum of the operator that is adjoint to the dynamics generator corresponding to the differential part. The results of this paper will be important for the reconstruction of the solution of the original initial boundary‐value problem from its Laplace transform and for the analysis of the flutter phenomenon in the forthcoming work. Copyright © 2004 John Wiley & Sons, Ltd.
Efficient distributions of arms‐control inspection effort
Authors: Avenhaus Rudolf , Kilgour D. Marc 
Published: January 2004

AbstractA rule that constrains decision‐makers is enforced by an inspector who is supplied with a fixed level of inspection resources—inspection personnel, equipment, or time. How should the inspector distribute its inspection resources over several independent inspectees? What minimum level of resources is required to deter all violations? Optimal enforcement problems occur in many contexts; the motivating application for this study is the role of the International Atomic Energy Agency in support of the Treaty on the Non‐Proliferation of Nuclear Weapons. Using game‐theoretic models, the resource level adequate for deterrence is characterized in a two‐inspectee problem with inspections that are imperfect in the sense that violations can be missed. Detection functions, or probabilities of detecting a violation, are assumed to be increasing in inspection resources, permitting optimal allocations over inspectees to be described both in general and in special cases. When detection functions are convex, inspection effort should be concentrated on one inspectee chosen at random, but when they are concave it should be spread deterministicly over the inspectees. Our analysis provides guidance for the design of arms‐control verification operations, and implies that a priori constraints on the distribution of inspection effort can result in significant inefficiencies. © 2003 Wiley Periodicals, Inc. Naval Research Logistics, 2004.
Fitting Lanchester equations to the battles of Kursk and Ardennes
Authors: Lucas Thomas W. , Turkes Turker 
Published: January 2004

AbstractLanchester equations and their extensions are widely used to calculate attrition in models of warfare. This paper examines how Lanchester models fit detailed daily data on the battles of Kursk and Ardennes. The data on Kursk, often called the greatest tank battle in history, was only recently made available. A new approach is used to find the optimal parameter values and gain an understanding of how well various parameter combinations explain the battles. It turns out that a variety of Lanchester models fit the data about as well. This explains why previous studies on Ardennes, using different minimization techniques and data formulations, have found disparate optimal fits. We also find that none of the basic Lanchester laws (i.e., square, linear, and logarithmic) fit the data particularly well or consistently perform better than the others. This means that it does not matter which of these laws you use, for with the right coefficients you will get about the same result. Furthermore, no constant attrition coefficient Lanchester law fits very well. The failure to find a good‐fitting Lanchester model suggests that it may be beneficial to look for new ways to model highly aggregated attrition. © 2003 Wiley Periodicals, Inc. Naval Research Logistics, 2004.
Effects of lethality in naval combat models
Authors: Armstrong Michael J. 
Published: January 2004

AbstractIn the context of both discrete time salvo models and continuous time Lanchester models we examine the effect on naval combat of lethality: that is, the relative balance between the offensive and defensive attributes of the units involved. We define three distinct levels of lethality and describe the distinguishing features of combat for each level. We discuss the implications of these characteristics for naval decision‐makers; in particular, we show that the usefulness of the intuitive concept “more is better” varies greatly depending on the lethality level. © 2003 Wiley Periodicals, Inc. Naval Research Logistics, 2004.
A note on scheduling parallel machines subject to breakdown and repair
Authors: Leung Joseph Y.‐T. , Pinedo Michael 
Published: January 2004

AbstractIn this paper we consider n jobs and a number of machines in parallel. The machines are identical and subject to breakdown and repair. The number may therefore vary over time and is at time t equal to m(t). Preemptions are allowed. We consider three objectives, namely, the total completion time, ∑ Cj, the makespan Cmax, and the maximum lateness Lmax. We study the conditions on m(t) under which various rules minimize the objective functions under consideration. We analyze cases when the jobs have deadlines to meet and when the jobs are subject to precedence constraints. © 2003 Wiley Periodicals, Inc. Naval Research Logistics, 2004.
Facility location models for immobile servers with stochastic demand
Authors: Wang Qian , Batta Rajan , Rump Christopher M. 
Published: January 2004

AbstractThis paper presents several models for the location of facilities subject to congestion. Motivated by applications to locating servers in communication networks and automatic teller machines in bank systems, these models are developed for situations in which immobile service facilities are congested by stochastic demand originating from nearby customer locations. We consider this problem from three different perspectives, that of (i) the service provider (wishing to limit costs of setup and operating servers), (ii) the customers (wishing to limit costs of accessing and waiting for service), and (iii) both the service provider and the customers combined. In all cases, a minimum level of service quality is ensured by imposing an upper bound on the server utilization rate at a service facility. The latter two perspectives also incorporate queueing delay costs as part of the objective. Some cases are amenable to an optimal solution. For those cases that are more challenging, we either propose heuristic procedures to find good solutions or establish equivalence to other well‐studied facility location problems. © 2003 Wiley Periodicals, Inc. Naval Research Logistics, 2004.
Ketolide:Klinische Aspekte: Stellenwert bei Atemwegsinfektionen
Authors: Lorenz Joachim , Steiert Petra 
Published: January 2004

AbstractTelithromycin, der erste Vertreter der Ketolide, besitzt eine hohe In‐vitro‐Aktivität gegen Erreger ambulant erworbener Atemwegsinfektionen. Das Wirkspektrum umfasst auch atypische und intrazelluläre Erreger sowie Pneumokokken (einschließlich Penicillin‐ und Makrolid‐resistente Stämme) und β‐Laktamasebildende Stämme von Haemophilus influenzae und Moraxella catarrhalis. Die Wirksamkeit von Telithromycin wurde in mehreren randomisierten Doppelblindstudien untersucht. Bei Patienten mit AECB, CAP, akuter Sinusitis und Tonsillitis/Pharyngitis war Telithromycin bei einer täglichen Einmalgabe von 800 mg und kürzerer Therapiedauer sowohl klinisch als auch bakteriologisch mindestens genauso effektiv und genauso gut verträglich wie Standardantibiotika. Telithromycin stellt somit eine wertvolle Bereicherung des Antibiotikaspektrums dar und ist eine viel versprechende Substanz zur Therapie von leichten bis mittelschweren ambulant erworbenen Atemwegsinfektionen.
Unerwünschte Wirkungen und Interaktionen der Ketolide und Oxazolidinone: Verträglichkeit von Antiinfektiva
Authors: Stahlmann Ralf , Sendzik Judith 
Published: January 2004

AbstractTelithromycin und Linezolid sind jeweils die ersten verfügbaren Antiinfektiva aus zwei neuen Arzneimittelgruppen: den Ketoliden und den Oxazolidinonen. Bei Patienten, die mit dem Ketolid Telithromycin behandelt wurden, kam es relativ häufig zur Diarrhö. Telithromycin hemmt unter anderem das Cytochrom Isoenzym CYP3A4, damit besteht ein ausgeprägtes Potenzial für klinisch relevante Wechselwirkungen mit anderen Arzneimitteln. Es besteht die Aufgabe für Ärzte und Apotheker auf die möglichen Interaktionen bei der Verschreibung und Abgabe des Ketolids hinzuweisen. Das Oxazolidinon Linezolid besitzt ein hämatotoxisches Potenzial, das bei mehrwöchiger Therapie zu Anämie, Leukopenie oder Thrombozytopenie führen kann. Wöchentliche Blutbildkontrollen sind notwendig, um Komplikationen rechtzeitig zu erkennen. Linezolid ist ein Hemmstoff der Monoaminoxidase und darf nicht mit anderen MAO‐Hemmern, Serotonin‐Wiederaufnahme‐Hemmern und einigen anderen Arzneimitteln kombiniert werden, da es sonst zum Serotonin‐Syndrom kommen kann. Bei wohlüberlegter Anwendung und unter Berücksichtigung der spezifischen pharmakologisch‐toxikologischen Wirkungen sind die beiden neuen Arzneimittel sichere und sinnvolle Ergänzungen der antibakteriellen Therapeutika.
Outcome of pediatric recurrent and refractory malignant solid tumors following ifosfamide/carboplatin/etoposide (ICE): A phase II study in a pediatric oncology centre in Brazil
Authors: Loss Jiseh Fagundes , Santos Pedro Paulo Albino , Leone Luciane Di , Brunetto Algemir Lunardi 
Published: January 2004

AbstractBackgroundTherapeutic trials using ifosfamide,carboplatin, and etoposide (ICE) regimen have suggested many patients with refractory/relapsed solid tumors may be rendered free of disease using this combination. The aim of this study was to assess the feasibility, response and toxicity of this regimen in a Brazilian Pediatric Oncology Centre.ProcedureICE, consisting of ifosfamide 3 g/m2/day ×3 plus Mesna, etoposide 160 mg/m2/day ×3, and carboplatin 400 mg/m2/day ×2 was given at 21–28 days intervals. G‐CSF was used for patients with hematological recovery greater than 4 weeks.ResultsTwenty‐one patients younger than 18 years of age treated with this regimen were studied between July 1996 and November 2000. A total of 93 courses of ICE were administered. Leucopenia/neutropenia grades 3/4 were the most frequent severe adverse effects (82%). Grade 3/4 thrombocytopenia occurred in 73% of cycles, and anemia was common (61%). The most common grade 3/4 non‐hematologic toxicities were fever and proved infection occurring in 25% and 14% of the courses, respectively. Two patients developed renal tubular damage. Other less common grade 3/4 non‐hematologic toxicities included nausea and vomiting, hepatotoxicity, and stomatitis. The overall response rate (complete response/partial response) was 53%. The median progression‐free interval was 15.3 months, with a median survival of 24.2 months.ConclusionsAlthough ICE was associated with severe myelosuppression it produced objective response in about half of the cases. The most important non‐hematological toxicity was severe renal tubular damage. This regimen should only be used whenever hematological and infectious supportive care is available. © 2003 Wiley‐Liss, Inc.
Gastric stromal tumors in children
Authors: Haider N. , Kader M. , Mc Dermott M. , Devaney D. , Corbally M.T. , Fitzgerald R.J. 
Published: January 2004

AbstractGastrointestinal stromal tumors (GIST) in children are rare and their behavior has been regarded as difficult to predict on pathological criteria. We report our experience with two gastric GISTs in children aged 10 and 11 years. Both remain alive and free of disease at 5 years and 2 years respectively. Comparison of the pathological features in the resected specimens with a recently proposed guidelines for predicting outcome in this group of tumors is reported. © 2003 Wiley‐Liss, Inc.