Influences on the forming of microcracks in the structure of concrete

Mikrorisse sind bereits im unbelasteten Beton aufgrund des unterschiedlichen Verformungsverhaltens der einzelnen Komponenten vorhanden. Im Rahmen dieser Arbeit wurde eine Methode zur Visualisierung der Mikrorisse im Betongefüge entwickelt. An Probekörpern aus Hochfestem Beton wurden die Einflüsse auf die Bildung dieser Mikrorisse aus der Probekörpervorbereitung sowie aus der Betontechnologie, der Lagerung und einer mechanischen Belastung untersucht. Als Haupteinfluss auf die Mikrorissbildung zeigte sich das autogene Schwinden des Hochfesten Betons. Ausgangspunkt der Mikrorisse in der Mörtelmatrix sind stets Luftporen oder die Kontaktzone zur Gesteinskörnung. Der Einfluss vorhandener Mikrorisse auf die Festbeton- und Dauerhaftigkeitseigenschaften des Betons zeigte sich in den hier gemachten Tests an Hochfesten Betonen nicht eindeutig. Anhand eines Modellbetons und einer numerischen Modellierung wurde der Baustoff Beton mit dem Dreikomponentensystem Matrix, Kontaktzone und Gesteinskörnung nachgebildet. Am Beispiel des Parameters der Gesteinskörnungsgröße wurden die real entstandenen Mikrorisse mit den errechneten Zugspannungsergebnissen aus der Simulation verifiziert.Microcracks exist already in unloaded concrete due to the different deformation characteristics of its components. In the course of this thesis a method was developped to visualize microcracks in the structure of High Strength Concrete. The investigated parameters were focussed on parameters related to the preparation of the specimen, the concrete technology and also on the influences of curing conditions and applied mechnical load. The results proofed autogeneous shrinkage being the main influence on the formation of microcracks in the High Strength Concrete investigated. The microcracks in the paste started always from air voids or the contact zone between paste and aggregate. In the tests with High Strength Concrete no influences were observed of existing microcracks on the properties of hardened concrete and durability. A model concrete and a numerical model were made to reproduce the material concrete as a 3-component-system: paste, aggregate and contact zone. The parameter aggregate size was taken as an example to compare the developped microcracks in the real model concrete with the calculated results of tension stresses obtained for the numerical model

Sexual violence against women: a multidisciplinary integrated care model

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Unternehmensethik und Unternehmensführung: Überlegungen zur Implementationseffizienz der U.S.-Sentencing Guidelines

"Die 'US-Sentencing Guidelines' operieren zur Bekämpfung der Wirtschaftskriminalität auf zwei Ebenen mit unterschiedlichen Maßnahmen. Auf der Ebene 'Staat - Unternehmung' stellt das Strafrecht ökonomische Anreize (Strafnachlässe) bereit, auf der Ebene 'Unternehmung - Individuum' werden konkrete organisatorische Vorkehrungen für ein Ethik-Programm eingefordert. Auf beiden Ebenen erscheint dabei die Steuerungseffizienz der Guidelines stark situationsabhängig, wie durch Entwicklung geeigneter Situationstypologien gezeigt wird. Auf der zweiten Ebene geht es dabei um das zentralistische (tayloristische) Führungsmodell einerseits und moderne Formen der dezentralisierten Unternehmensführung andererseits. Diesen zwei Typen entsprechen auf der Seite des Ethik-Managements in struktureller Hinsicht das sog. 'Compliance-Modell' und das 'Integritätsmodell'. Es wird im Interesse der Effizienz dafür argumentiert, die Guidelines im Sinne des Integritätsmodells zu interpretieren und fortzuentwickeln. Damit werden zugleich eine strukturelle Deckungsgleichheit zwischen Ethik- Management und modernen Formen der Unternehmensführung erreicht und strukturbedingte Konflikte zwischen beiden Führungssystemen vermieden." (Autorenreferat

A Real-time Impedance-Based Screening Assay for Drug-Induced Vascular Leakage

Vascular leakage is a serious side effect of therapies based on monoclonal antibodies or cytokines which may lead to life-threatening situations. With the steady increase of new drug development programs for large molecules, there is an urgent need for reliable tools to assess this potential liability of new medicines in a rapid and cost-effective manner. Using human umbilical vein endothelial cells (HUVECs) as a model for endothelium, we established an impedance-based assay measuring the integrity of the endothelial cell monolayer in real time. We could demonstrate that the HUVEC monolayer in our system was a relevant model as cells expressed major junctional proteins known to be responsible for maintaining tightness as well as receptors targeted by molecules known to induce vascular leakage in vivo. We assessed the time-dependent loss of barrier function using impedance and confirmed that signals obtained corresponded well to those from standard transwell assays. We assayed a series of reference molecules which led to the expected change of barrier integrity. A nonspecific cytotoxic effect could be excluded by using human fibroblasts as a nonresponder cell line. Finally, we could show reversibility of vascular permeability induced by histamine, IL-1β, or TNF-α by coincubation with established antagonists, further demonstrating relevance of this new model. Taken together, our results suggest that impedance in combination with HUVECs as a specific model can be applied to assess clinically relevant vascular leakage on an in vitro leve

The medico-legal assessment of asylum seeker victims in Italy

Introduction: Changing patterns of migration hasrequired states andgovernments to respond to the specific medical and legal needs of asylum seekers. Based on medical assessments undertaken at the University Institute of Legal Medicine, the present study aims to describe the cases of asylum applicants who have suffered from physical violence, including torture, and the variables involved. Methods: Over a 10-year period, 225 survivors were examined by clinical forensic professionals from the University Institute of Legal Medicine. Results:85% of asylum applicants came from Africa, 87% were male, and the most common age group was 26-40 years old. 46% of applicants fled their country for political reasons. Blunt force injuries were reported in 45% of cases, the trunk was the most affected area of the body (40%), and applicants presented with an average of two different mechanisms of lesions and an average of four lesions each. Discussion/conclusion:Assessment of physical violence on asylum seekers requires the cooperation of professionals with different skillsets and training

Fetal Doppler changes one week after endoscopic equatorial laser for twin-to-twin transfusion syndrome: a longitudinal study

Objective: To investigate sequential Doppler changes in donors and recipients before and 1 week after endoscopic laser for twin\u2010to\u2010twin transfusion syndrome (TTTS) and to examine factors that may be associated with such changes. Methods: In TTTS pregnancies undergoing laser treatment, we examined fetal Doppler changes before and 1 week postintervention. Intrauterine death rates and preoperative factors were analyzed in relation to Doppler changes. Results: Among 129 (85.4%) donors surviving at 1 week after laser, there was normalization of umbilical artery flow in 26 (72.2%) of 36 cases with preoperative abnormal Dopplers. In the remaining 10 (27.8%) fetuses, abnormal findings persisted. The rate of later intrauterine death was significantly higher in the latter group (6 of 10, 60.0%) compared with fetuses in which Doppler findings normalized (4 of 26, 15.4%; P < .05), with no difference in the rate of severe donor growth restriction between the 2 groups (80.0% vs 65.4%, respectively; P = .688). Conclusions: In about 70% of TTTS donors with preoperative abnormal umbilical artery Doppler, there was normalization 1 week after endoscopic laser. The incidence of fetal growth restriction was not significantly different in donors with persistence of Doppler abnormalities compared with those with normalized findings

Current approaches and future role of high content imaging in safety sciences and drug discovery

High content imaging combines automated microscopy with image analysis approaches to simultaneously quantify multiple phenotypic and/or functional parameters in biological systems. The technology has become an important tool in the fields of safety sciences and drug discovery, because it can be used for mode-of-action identification, determination of hazard potency and the discovery of toxicity targets and biomarkers. In contrast to conventional biochemical endpoints, high content imaging provides insight into the spatial distribution and dynamics of responses in biological systems. This allows the identification of signaling pathways underlying cell defense, adaptation, toxicity and death. Therefore high content imaging is considered a promising technology to address the challenges for the Toxicity testing in the 21st century approach. Currently high content imaging technologies are frequently applied in academia for mechanistic toxicity studies and in pharmaceutical industry for the ranking and selection of lead drug compounds or to identify/confirm mechanisms underlying effects observed in vivo. A recent workshop gathered scientists working on high content imaging in academia, pharmaceutical industry and regulatory bodies with the objective to compile the state-of-the-art of the technology in the different institutions. They defined technical and methodological gaps, addressed the need for quality control, suggested control compounds and acceptance criteria, highlighted cell sources and new readouts and discussed future requirements for regulatory implementation. This review summarizes the discussion, proposed solutions and recommendations of the specialists contributing to the workshop.JRC.I.5-Systems Toxicolog