2,566 research outputs found
A branch-and-prune algorithm for discrete Nash equilibrium problems
We present a branch-and-prune procedure for discrete Nash equilibrium problems with a convex description of each player’s strategy set. The derived pruning criterion does not require player convexity, but only strict convexity of some player’s objective function in a single variable. If satisfied, it prunes choices for this variable by stating activity of certain constraints. This results in a synchronous branching and pruning method. An algorithmic implementation and numerical tests are presented for randomly generated instances with convex polyhedral strategy sets and convex quadratic as well as non-convex quadratic objective functions
Selective non-steroidal glucocorticoid receptor agonists attenuate inflammation but do not impair intestinal epithelial cell restitution in vitro
Introduction: Despite the excellent anti-inflammatory and immunosuppressive action of glucocorticoids (GCs), their use for the treatment of inflammatory bowel disease (IBD) still carries significant risks in terms of frequently occurring severe side effects, such as the impairment of intestinal tissue repair. The recently-introduced selective glucocorticoid receptor (GR) agonists (SEGRAs) offer anti-inflammatory action comparable to that of common GCs, but with a reduced side effect profile.
Methods: The in vitro effects of the non-steroidal SEGRAs Compound A (CpdA) and ZK216348, were investigated in intestinal epithelial cells and compared to those of Dexamethasone (Dex). GR translocation was shown by immunfluorescence and Western blot analysis. Trans-repressive effects were studied by means of NF-κB/p65 activity and IL-8 levels, trans-activation potency by reporter gene assay. Flow cytometry was used to assess apoptosis of cells exposed to SEGRAs. The effects on IEC-6 and HaCaT cell restitution were determined using an in vitro wound healing model, cell proliferation by BrdU assay. In addition, influences on the TGF-β- or EGF/ERK1/2/MAPK-pathway were evaluated by reporter gene assay, Western blot and qPCR analysis.
Results: Dex, CpdA and ZK216348 were found to be functional GR agonists. In terms of trans-repression, CpdA and ZK216348 effectively inhibited NF-κB activity and IL-8 secretion, but showed less trans-activation potency. Furthermore, unlike SEGRAs, Dex caused a dose-dependent inhibition of cell restitution with no effect on cell proliferation. These differences in epithelial restitution were TGF-β-independent but Dex inhibited the EGF/ERK1/2/MAPK-pathway important for intestinal epithelial wound healing by induction of MKP-1 and Annexin-1 which was not affected by CpdA or ZK216348.
Conclusion: Collectively, our results indicate that, while their anti-inflammatory activity is comparable to Dex, SEGRAs show fewer side effects with respect to wound healing. The fact that SEGRAs did not have a similar effect on cell restitution might be due to a different modulation of EGF/ERK1/2 MAPK signalling
Providing Spontaneous WLAN Guest Access as a Mobile Value Added Service
In this paper we describe the design and realization of a system that
allows guests to connect to a company’s internet-access channel via wireless
local area network (WLAN). The core of the corporate infrastructure stays
protected against unauthorized access. Although a growing number of
companies provide WLAN access for their employees, guest access is rarely
granted due to security concerns and substantial maintenance hurdles. Even if
a network administrator might be willing to provide such access, it often
would be done manually with substantial time delay. The solution we propose
to solve this problem and to simplify the whole procedure is based on
establishing a chain of trust. An authorized corporate user assumes the role of
a host who invites and trusts his guests, thus he issues access codes together
with the invitations. The system we propose is composed of two scenarios.
The first scenario is called the „consultant scenario“ and uses a Spontaneous
WLAN Guest Access Server (SpoGA Server). In the second scenario, the so
called „congress scenario“, we describe how to support a great number of
guests. Here we propose an „Extended Invitation Management System” (E–
IMS) for ease of use. This system can help organizers of events not only to
provide participants with wireless network access but also to support other
related tasks in the preparation of larger events. The current results as
described in the paper pave the way for field testing and broad enrollment. In
addition some considerations on further developments are provided
A Mobile Accident Report System
Rarely performed documentation tasks usually require support for the user so that the data is recorded both completely and correctly. The broad market penetration with mobile devices like smart phones provides new possibilities for giving support for these kinds of tasks. This paper focuses on one particular widely-used instance of such a documentation task, namely the European Accident Report (aka Agreed Statement of Facts on Motor Vehicle Accident). Firstly we discuss the advantages of media-break-free processing of all the relevant data. Secondly we present the client part of the application, which allows on-site documentation by any of the parties involved. Both application parts can be used for processing claims in the back office. We highlight the possibilities of service-chain integration, the digital accident file generated by using this solution and the resultant advantages for media-break-free processing of claims
Quantum chromodynamics
The book is a self-contained introduction to perturbative and nonperturbative Quantum chromodynamics (QCD) with worked-out exercises for students of theoretical physics. It will be useful as a reference for research scientists as well. Starting with the hadron spectrum, the reader becomes familiar with the representations of SU(N). Relativistic quantum field theory is recapitulated, and scattering theory is discussed in the framework of scalar quantum electrodynamics. Then the gauge theory of quarks and gluons is introduced. In the more advanced chapters, perturbative and nonperturbative techniques in state-of-the-art QCD are discussed in great detail. The new third edition has been extensively revised and enlarged to cover all new aspects in Quantum chromodynamics
Tibiofemoral and patellofemoral joint 3D-kinematics in patients with posterior cruciate ligament deficiency compared to healthy volunteers
Background: The posterior cruciate ligament (PCL) plays an important role in maintaining physiological kinematics and function of the knee joint. To date mainly in-vitro models or combined magnetic resonance and fluoroscopic systems have been used for quantifying the importance of the PCL. We hypothesized, that both tibiofemoral and patellofemoral kinematic patterns are changed in PCL-deficient knees, which is increased by isometric muscle flexion. Therefore the aim of this study was to simultaneously investigate tibiofemoral and patellofemoral 3D kinematics in patients suffering from PCL deficiency during different knee flexion angles and under neuromuscular activation.
Methods: We enrolled 12 patients with isolated PCL-insufficiency as well as 20 healthy volunteers. Sagittal MR-images of the knee joint were acquired in different positions of the knee joint (0[degree sign], 30[degree sign], 90[degree sign] flexion, with and without flexing isometric muscle activity) on a 0.2 Tesla open MR-scanner. After segmentation of the patella, femur and tibia local coordinate systems were established to define the spatial position of these structures in relation to each other.
Results: At full extension and 30[degree sign] flexion no significant difference was observed in PCL-deficient knee joints neither for tibiofemoral nor for patellofemoral kinematics. At 90[degree sign] flexion the femur of PCL-deficient patients was positioned significantly more anteriorly in relation to the tibia and both, the patellar tilt and the patellar shift to the lateral side, significantly increased compared to healthy knee joints. While no significant effect of isometric flexing muscle activity was observed in healthy individuals, in PCL-deficient knee joints an increased paradoxical anterior translation of the femur was observed at 90[degree sign] flexion compared to the status of muscle relaxation.
Conclusions:
Significant changes in tibiofemoral and patellofemoral joint kinematics occur in patients with isolated PCL-insufficiency above 30 degrees of flexion compared to healthy volunteers. Since this could be one reasonable mechanism in the development of OA our results might help to understand the long-term development of tibiofemoral and/or patellofemoral osteoarthritis in PCL-insufficient knee joints
New Approaches for ab initio Calculations of Molecules with Strong Electron Correlation
Reliable quantum chemical methods for the description of molecules with
dense-lying frontier orbitals are needed in the context of many chemical
compounds and reactions. Here, we review developments that led to our
newcomputational toolbo x which implements the quantum chemical density matrix
renormalization group in a second-generation algorithm. We present an overview
of the different components of this toolbox.Comment: 19 pages, 1 tabl
Optimized Sound Field Generation in the Time Domain – Validation for Source Arrays in 2D
DFG, 393106680, Optimale Schallfelderzeugung fĂĽr Beschallungsaufgaben im Zeit- und Frequenzbereic
Quantifizierung der dreidimensionalen Mikroarchitektur von Genomelementen nach spezifischer Fluoreszenzmarkierung in fixierten und vitalen Zellen
Die Erforschung der Chromatinstruktur in Interphasezellkernen basiert im Wesentlichen auf der in situ Hybridisierung von fluoreszenzmarkierten Sonden (=FISH), lichtoptischen Mikroskopieverfahren und digitaler Bildanalyse. Für die Quantifizierung der Bildinformation wurden neue effiziente Algorithmen entwickelt und anschließend auf verschiedene biologische Systeme angewendet. Zur quantitativen Analyse der Topologie und Morphologie von spezifisch fluoreszenzmarkierten Chromatinregionen wurde ein Softwarepaket entwickelt, welches folgende Parameter mißt: absolute und relative Positionen, normierte und absolute Distanzen, Schwerpunktswinkel von Chromatinregionen und die Minkowskifunktionale von Chromosomenterritorien. Die Anpassung eines Ellipsoidmodells an Zellkerne wurde mittels Lagranger Optimierung realisiert. Zusätzlich wurde ein Algorithmus entwickelt, welcher das Kugel-, Ellipsoidvolumen und die Kompaktierung von markierten Genen anhand der Halbwertsbreiten einer an die Intensitätsverteilung angepaßten zweidimensionalen Gaußverteilung bestimmt. Das Softwarepaket wurde an den Chromosomenterritorien 18 und 19 in Fibroblastenzellkernen getestet. Die Anwendung auf Zellkerne des Cervix-Gewebes erlaubte es erstmals ein vollständiges topologisches Modell des Chromosomenterritoriums 18 und des BCL2 Gens mit der Differenzierung und Expression zu verknüpfen. Das Kugel-, Ellipsoidvolumen und die Kompaktierung des SNRPN Gens wurden abgeschätzt. Es konnte aufgezeigt werden, dass herkömmliche Meßmethoden unzureichend sind, daß aber auch FISH-Artefakte das Ergebnis beeinussen können. Daher wurde eine neue Methode zur vitalen kombinatorischen Oligonukleotid-FISH (=vCF) eingeführt. Während bei allen Standard-FISH Methoden destruktive Veränderungen der Chromatinstruktur auftreten können, ermöglicht die vCF eine schonende in situ Hybridisierung in lebenden T-Lymphozyten
A meta-analysis of pharmacotherapy for social anxiety disorder: an examination of efficacy, moderators, and mediators
INTRODUCTION: Social anxiety disorder (SAD) is among the most prevalent mental disorders, associated with impaired functioning and poor quality of life. Pharmacotherapy is the most widely utilized treatment option. The current study provides an updated meta-analytic review of the efficacy of pharmacotherapy and examines moderators and mediators of treatment efficacy. Areas Covered: A comprehensive search of the current literature yielded 52 randomized, pill placebo-controlled trials of pharmacotherapy for adults diagnosed with SAD. Data on potential mediators of treatment outcome were collected, as well as data necessary to calculate pooled correlation matrices to compute indirect effects. Expert Opinion: The overall effect size of pharmacotherapy for SAD is small to medium (Hedges' g = 0.41). Effect sizes were not moderated by age, sex, length of treatment, initial severity, risk of study bias, or publication year. Furthermore, reductions in symptoms mediated pharmacotherapy's effect on quality of life. Support was found for reverse mediation. Future directions may include sustained efforts to examine treatment mechanisms of pharmacotherapy using rigorous longitudinal methodology to better establish temporal precedence
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