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Search Results: 1 - 10 of 9840 matches for " Stefan Kaltenbach "
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Conductance and Capacity of Plain Lipid Membranes under Conditions of Variable Gravity  [PDF]
Michaela Sieber, Stefan Kaltenbach, Wolfgang Hanke, Florian P. M. Kohn
Journal of Biomedical Science and Engineering (JBiSE) , 2016, DOI: 10.4236/jbise.2016.98031
Abstract: Biological cell membranes are complex structures containing mainly lipids and proteins. Functional aspects of such membranes are usually attributed to membrane integral proteins. However, it is well established that parameters of the lipid matrix are modifying the function of proteins. Additionally, electrical capacity and conductance of the plain lipid matrix of membranes are contributing directly to cellular functions as there is, for example, the propagation of action potentials. Accordingly the dependence of these parameters on changes of gravity might be important in the field of life sciences under space conditions. In this study consequently we have performed experiments in parabolic flight campaigns utilizing the patch-clamp technology to investigate conductance and capacity of plain lipid vesicle membranes under conditions of changing gravity. Both capacity and conductance were found to be gravity dependent. The changes in capacity could be contributed to changes in membrane geometry. Significant permeability in plain lipid membranes could be only observed at high potentials, where spontaneous current fluctuations occurred. The probability of these fluctuations was gravity dependent.
A unified view on bipartite species-reaction and interaction graphs for chemical reaction networks
Hans-Michael Kaltenbach
Quantitative Biology , 2012,
Abstract: The Jacobian matrix of a dynamic system and its principal minors play a prominent role in the study of qualitative dynamics and bifurcation analysis. When interpreting the Jacobian as an adjacency matrix of an interaction graph, its principal minors correspond to sets of disjoint cycles in this graph and conditions for various dynamic behaviors can be inferred from its cycle structure. For chemical reaction systems, more fine-grained analyses are possible by studying a bipartite species-reaction graph. Several results on injectivity, multistationarity, and bifurcations of a chemical reaction system have been derived by using various definitions of such bipartite graph. Here, we present a new definition of the species-reaction graph that more directly connects the cycle structure with determinant expansion terms, principal minors, and the coefficients of the characteristic polynomial and encompasses previous graph constructions as special cases. This graph has a direct relation to the interaction graph, and properties of cycles and sub-graphs can be translated in both directions. A simple equivalence relation enables to decompose determinant expansions more directly and allows simpler and more direct proofs of previous results.
Effectiveness of a Smoking Cessation Intervention for Methadone-Maintained Women: A Comparison of Pregnant and Parenting Women
Amber M. Holbrook,Karol A. Kaltenbach
International Journal of Pediatrics , 2011, DOI: 10.1155/2011/567056
Abstract: Women in substance abuse programs have high rates of smoking. Pregnancy represents a unique opportunity for intervention, but few data exist to guide tailoring of effective interventions. In this study, 44 pregnant and 47 nonpregnant opioid-dependent women enrolled in comprehensive substance abuse treatment received a 6-week smoking cessation intervention based on the 5A's counseling model. The number of daily cigarettes decreased by 49% for pregnant patients and 32% for nonpregnant patients at the 3-month followup. Length of time in substance abuse treatment did not correlate with smoking cessation or reduction for either group. Factors predicting reduction of cigarette smoking differed for pregnant versus nonpregnant patients. For pregnant patients, lower levels of nicotine use prior to intervention and self-reported cigarette cravings predicted successful reduction in smoking. For nonpregnant patients, lower affiliative attachment to cigarettes, reliance on cigarettes for cognitive enhancement, and greater sense of control predicted more successful outcomes.
Effectiveness of a Smoking Cessation Intervention for Methadone-Maintained Women: A Comparison of Pregnant and Parenting Women
Amber M. Holbrook,Karol A. Kaltenbach
International Journal of Pediatrics , 2011, DOI: 10.1155/2011/567056
Abstract: Women in substance abuse programs have high rates of smoking. Pregnancy represents a unique opportunity for intervention, but few data exist to guide tailoring of effective interventions. In this study, 44 pregnant and 47 nonpregnant opioid-dependent women enrolled in comprehensive substance abuse treatment received a 6-week smoking cessation intervention based on the 5A's counseling model. The number of daily cigarettes decreased by 49% for pregnant patients and 32% for nonpregnant patients at the 3-month followup. Length of time in substance abuse treatment did not correlate with smoking cessation or reduction for either group. Factors predicting reduction of cigarette smoking differed for pregnant versus nonpregnant patients. For pregnant patients, lower levels of nicotine use prior to intervention and self-reported cigarette cravings predicted successful reduction in smoking. For nonpregnant patients, lower affiliative attachment to cigarettes, reliance on cigarettes for cognitive enhancement, and greater sense of control predicted more successful outcomes. 1. Introduction Tobacco use represents a significant long-term risk to women’s health [1, 2], and cigarette smoking is currently one of the leading preventable causes of poor pregnancy outcomes, as well as infant mortality and morbidity [3]. Smoking during pregnancy is associated with increased risk of preterm birth [4–6], placental abruption, placenta previa, low birth weight [6–8], and sudden infant death syndrome (SIDS) [9, 10]. The risks related to cigarette smoking continue following birth with child exposure to second hand tobacco smoke associated with an increased incidence of respiratory ailments such as asthma, respiratory infections, and bronchiolitis [11–13]. Estimates of the prevalence of smoking in participants in methadone maintenance programs range from 85 to 98% [14–17]. However, few substance abuse treatment programs offer smoking cessation interventions, and smoking cessation is often viewed as a low priority by treatment program staff [18]. Treatment staff may perceive substance-dependent individuals as possessing low motivation for smoking cessation [19] or believe that engaging in efforts to reduce nicotine dependence may be overwhelming for substance-dependent individuals, particularly those early in their recovery [18]. Some studies have also suggested that methadone maintenance may compound difficulty quitting smoking with a dose-dependent effect on tobacco craving and nicotine withdrawal symptoms [20, 21] affected through increased rate of nicotine metabolism or
Antibody dynamics and spontaneous viral clearance in patients with acute hepatitis C infection in Rio de Janeiro, Brazil
Alexander M Strasak, Arthur Y Kim, Georg M Lauer, Paulo S de Sousa, Cleber F Ginuino, Carlos A Fernandes, Carlos E Velloso, Adilson J de Almeida, Jaqueline M de Oliveira, Clara F Yoshida, Julian zur Wiesch, Gláucia Paranhos-Baccalá, Stefan Lang, Larry J Brant, Hanno Ulmer, Susanne Strohmaier, Lalit Kaltenbach, Elisabeth Lampe, Lia L Lewis-Ximenez
BMC Infectious Diseases , 2011, DOI: 10.1186/1471-2334-11-15
Abstract: We analyzed serial anti-HCV antibodies longitudinally obtained from a prospective cohort of 65 patients with acute HCV infection by using a microparticle enzyme immunoassay AxSYM HCV 3.0 (Abbott Diagnostics) during the first 12 months from HCV acquisition in Rio de Janeiro, Brazil. Spontaneous viral clearance (SVC) was defined as undetectable HCV RNA in serum, in the absence of treatment, for three consecutive HCV PCR tests within 12-months of follow-up.Baseline antibody values were similar among patient groups with self-limiting HCV evolution (n = 34) and persistent viremia (n = 31) [median (interquartile range) signal/cut-off ratio (s/co) 78.7 (60.7-93.8) vs. 93.9 (67.8-111.9), p = 0.26]. During 12-months follow-up, patients with acute spontaneous resolving HCV infection showed significantly lower serial antibody response in comparison to individuals progressing to chronic infection [median (interquartile range) s/co 62.7 (35.2-85.0) vs. 98.4 (70.4-127.4), p < 0.0001]. In addition, patients with self-limiting HCV evolution exhibited an expeditious, sharp decline of serial antibody values after SVC in comparison to those measured before SVC [median (interquartile range) s/co 56.0 (25.4-79.3) vs. 79.4 (66.3-103.0), p < 0.0001].Our findings indicate a rapid short-term decline of antibody values in patients with acute spontaneous resolving HCV infection.Acute hepatitis C virus (HCV) infection accounts for approximately 20% of cases of acute hepatitis today, with an estimated 30,000 to 40,000 new cases occurring every year in the United States alone. Worldwide at least 170 million individuals are chronically infected with HCV [1-4]. The natural history of HCV infection is heterogeneous and incorporates a range of prognostic determinants [1-6]. Untreated, acute HCV infection progresses to chronic infection in 50-80% of patients [7-9]. Rates of spontaneous HCV resolution (SVC) reported from prospective studies substantially vary, with estimates ranging from 10 to 60% [2-
SAMPI: Protein Identification with Mass Spectra Alignments
Hans-Michael Kaltenbach, Andreas Wilke, Sebastian B?cker
BMC Bioinformatics , 2007, DOI: 10.1186/1471-2105-8-102
Abstract: We present an unified framework for analyzing Peptide Mass Fingerprints that offers a number of advantages over existing methods: First, comparison of mass spectra is based on a scoring function that can be custom-designed for certain applications and explicitly takes missing and additional peaks into account. The method is able to simulate almost every additive scoring scheme. Second, we present an efficient deterministic method for assessing the significance of a protein hit, independent of the underlying scoring function and sequence database. We prove the applicability of our approach using biological mass spectrometry data and compare our results to the standard software Mascot.The proposed framework for analyzing Peptide Mass Fingerprints shows performance comparable to Mascot on small peak lists. Introducing more noise peaks, we are able to keep identification rates at a similar level by using the flexibility introduced by scoring schemes.Protein identification using mass spectrometry has become one of the central tools in proteomics and systems biology [1]: With growing protein sequence databases such as SwissProt [2], fast and accurate identification of a sample protein remains a central problem. There are two common strategies for protein identification using mass spectrometry: Peptide Mass Fingerprints [3] and protein identification from peptide sequence information using tandem mass spectrometry [4].Peptide mass fingerprinting (PMF) is preceded by a protein separation step using gel or chromatographic separation. The separated protein is digested by specific enzymatic cleavage such as tryptic digestion, followed by mass spectrometric measurement of the resulting peptides. The resulting mass spectrum has to be preprocessed into a list of signal peaks that form the input to identification algorithms. In our approach, we concentrate on Matrix Assisted Laser Desorption/Ionization (MALDI) [5], the predominant ionization technique for PMF. This technique produ
Aleteo auricular neonatal
Kaltenbach,Germán; Pérez,Susana; Vallejo,Carlos;
Archivos argentinos de pediatr?-a , 2007,
Abstract: atrial flutter is an uncommon arrhythmia in the newborn period; however, it must be considered in patients who have congestive heart failure with or without dilated cardiomyopathy (tachycardiomyopathy). neonatal atrial flutter has significant morbidity but an excellent long-term prognosis. the treatment options are diverse, with different rates of results in the centres′ reports, but virtually all infants will respond to direct current synchronized cardioversion. we describe a boy who developed the condition in the newborn period and whose diagnosis was established at 35 days of life. electrical cardioversion and amiodarone was performed with good evolution.
Herzkathetereingriffe in sterreich im Jahr 2010 (mit Audit 2004 bis 2011)
Mühlberger V,Kobel C,Kaltenbach L,Pachinger O
Journal für Kardiologie , 2012,
Abstract: Im Jahr 2010 best tigte sich die Plateaubildung der Leistungszahlen der in sterreich seit dem Jahr 2005 durchgeführten diagnostischen (CA) und interventionellen (PCI) Eingriffe an den Herzkranzgef en. Die Anzahl der sogenannten low volumes centers , die in den Jahren 2004 2007 zugenommen hat, ist seither konstant geblieben. Die Anzahl der akuten Interventionen erreichte nach einer rasanten Steigerung bis in das Jahr 2008 erstmals einen konstanten Prozentsatz gegenüber den Routine-Katheterisierungen. 23 der 37 Zentren meldeten für das Jahr 2010 die anzustrebende Zahl von mehr als 36 interventionellen Eingriffen bei STHebungsinfarkten (STEMI). Die H ufigkeit der Verwendung von beschichteten und unbeschichteten Stents ist in sterreich im Zeitraum von 2005 2010 weitgehend konstant geblieben. Bei den Eingriffen wegen akuter oder chronischer Restenose ist eine Konsolidierung eingetreten. Es ist eine Zunahme bei diversen Nischenanwendungen zu verzeichnen: Punktionen vom Arm aus Intrakoronare Druckmessungen Gerinnsel-Entferner Optical Coherence Tomography (OCT). Die seit dem Jahr 2007 angebotene perkutane Aortenklappenersatztherapie (TAVI) weist bis 2010 deutlich steigende Anwendungszahlen auf. Die seit 2009 neu angewandte interventionelle Therapie der Mitralklappeninsuffizienz mittels MitraClip zeigt 2010 eine deutlich gesteigerte Fallzahl auf. Absolut neu in sterreich ist im Jahr 2010 zur neuroregulatorischen Behandlung der arteriellen Hypertonie die Durchführung der perkutanten, renalen Denervation (PRD) im Katheterlabor mit (n = 35) F llen. Der internationale Vergleich von 2009/2010 zeigt, dass die Schweiz mit 2571/2693 PCI pro Million Einwohner pro Jahr sterreich mit 2364/2428 PCI pro Million Einwohner pro Jahr erstmals seit 2004 wieder überholt hat. Im Jahr 2010 ist das Verh ltnis PCI/CA in der Schweiz (46,7 %) auch persistent h her als in sterreich (36,8 %). Die Daten werden in traditioneller Weise seit 1995 über die Webseite: http://iik.i-med.ac.at/ publiziert.
Probabilistic Arithmetic Automata and their Applications
Tobias Marschall,Inke Herms,Hans-Michael Kaltenbach,Sven Rahmann
Computer Science , 2010,
Abstract: We present probabilistic arithmetic automata (PAAs), a general model to describe chains of operations whose operands depend on chance, along with two different algorithms to exactly calculate the distribution of the results obtained by such probabilistic calculations. PAAs provide a unifying framework to approach many problems arising in computational biology and elsewhere. Here, we present five different applications, namely (1) pattern matching statistics on random texts, including the computation of the distribution of occurrence counts, waiting time and clump size under HMM background models; (2) exact analysis of window-based pattern matching algorithms; (3) sensitivity of filtration seeds used to detect candidate sequence alignments; (4) length and mass statistics of peptide fragments resulting from enzymatic cleavage reactions; and (5) read length statistics of 454 sequencing reads. The diversity of these applications indicates the flexibility and unifying character of the presented framework. While the construction of a PAA depends on the particular application, we single out a frequently applicable construction method for pattern statistics: We introduce deterministic arithmetic automata (DAAs) to model deterministic calculations on sequences, and demonstrate how to construct a PAA from a given DAA and a finite-memory random text model. We show how to transform a finite automaton into a DAA and then into the corresponding PAA.
Comparison of Different Control Algorithms for a Gantry Crane System  [PDF]
Stefan Bruins
Intelligent Control and Automation (ICA) , 2010, DOI: 10.4236/ica.2010.12008
Abstract: For a gantry crane system, this paper presents a comparison between four control algorithms. These algo-rithms are being compared on simplicity, stability and robustness. Goal for the controller is to move the load on a gantry crane to a new position with minimal overshoot of the load and maximal speed of the load. An-other goal is to provide an insight in the behaviour of the possible controllers. In this article a parallel P-controller, cascade P-controller, fuzzy controller and an internal model controller are used. To be able to validate and design the controllers a model is derived from the gantry crane. The controllers and the model are being implemented in Matlab Simulink. Finally the controllers are validated and tuned in Labview on a laboratory gantry scrane scale model. Main conclusion is that all presented controllers can be used as a con-troller for the gantry crane system but the fuzzy controller is showing the best performance.
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