Search results for " strain"

Investigation of thick sheet AHSS springback in combined bending under tension

2012

In this paper, we investigate the springback behavior of several advanced high-strength sheet steels (TRIP, Dual-Phase, ferrite-bainite) with thicknesses up to 4 mm. Samples were tested by means of the bending-under-tension (BUT) test. The BUT has been extensively applied, in the literature, to relatively thin (1 mm and thinner) sheet metals for automotive applications; the applicability of several guidelines from the literature was investigated in this work in the context of thick advanced high strength steel (AHSS) sheets and using a sample width of 12 mm. The monotonic decrease of springback as back force increased was confirmed for this category of sheet steels, and a general trend for …

Modeling of out-of-plane behavior of masonry walls

2009

The flexural behavior of rectangular masonry sections is investigated by considering nonlinear stress-strain in compression and limited-tension material. A preliminary analysis shows that, with variation in the parameters specializing with the adopted conventional constitutive law, the experimentally observed behavior of different kinds of masonry materials can be approximated. Subsequently, moment-curvature dimensionless curves are derived numerically by satisfying the equilibrium equations of the section. In the case of negligible tensile strength these curves exhibit a typical shape that can be approximated by analytical expressions; consequently, suitable functions are proposed that are…

Analysis of the accuracy of fiber-optic strain transducers installed by using composite smart patches

2015

The aim of this work is to investigate the accuracy of fiber-optic strain transducer related to the incomplete load transmission that can occur on composite smart patches used as base support for the installation of such transducer, commonly used for structural monitoring of concrete elements. In detail, since the dimensions of the transducer are generally very small compared to those of the structural element being monitored, attention is given not to the global reinforcement effect, which occurs when the transducer alters the entire strain field of the transversal section of the monitored element, but rather to the so-called local reinforcement effect, which is due to an incomplete load …

Compressive behaviour of concrete elliptical columns confined by single hoops

2007

The compressive behaviour of short concrete members having elliptical cross-sections and confined with single steel hoops is investigated. An analytical model is given for calculation of the stress-strain curves of compressed members also including the valuation of the ultimate stress corresponding to formation of a complete failure plane in the concrete core. The model is able to evaluate the confining pressure due to steel hoops referring to a fictitious reduced area of the confined core and to the effective stresses in the hoops, which are variable along the perimeter; moreover, it makes it possible to determine the maximum compressive strength and the corresponding strain of the confine…

Biciliated ependymal cell proliferation contributes to spinal cord growth

2012

Two neurogenic regions have been described in the adult brain, the lateral ventricle subventricular zone and the dentate gyrus subgranular zone. It has been suggested that neural stem cells also line the central canal of the adult spinal cord. Using transmission and scanning electron microscopy and immunostaining, we describe here the organization and cell types of the central canal epithelium in adult mice. The identity of dividing cells was determined by 3D ultrastructural reconstructions of [3H]thymidine-labeled cells and confocal analysis of bromodeoxyuridine labeling. The most common cell type lining the central canal had two long motile (9+2) cilia and was vimentin+, CD24+, FoxJ1+, So…

TGF-beta regulates airway responses via T cells.

2003

Abstract Allergic asthma is characterized by airway hyperreactivity, inflammation, and a Th2-type cytokine profile favoring IgE production. Beneficial effects of TGF-β and conflicting results regarding the role of Th1 cytokines have been reported from murine asthma models. In this study, we examined the T cell as a target cell of TGF-β-mediated immune regulation in a mouse model of asthma. We demonstrate that impairment of TGF-β signaling in T cells of transgenic mice expressing a dominant-negative TGF-β type II receptor leads to a decrease in airway reactivity in a non-Ag-dependent model. Increased serum levels of IFN-γ can be detected in these animals. In contrast, after injection of OVA …

‘Threshold effect’ of increasing tocopherol ingestion upon the microsomal epoxide hydrolase activity of rat liver

1990

Microsomal and cytosolic epoxide hydrolases, the peroxisomal fatty acid beta-oxidation system and catalase. Activities, distribution and induction in…

1988

A number of structurally unrelated hypolipidaemic agents and certain phthalate-ester plasticizers induce hepatomegaly and proliferation of peroxisomes in rodent liver, but there is relatively limited data regarding the specific effects of these drugs on liver non-parenchymal cells. In the present study, liver parenchymal, Kupffer and endothelial cells from untreated and fenofibrate-fed rats were isolated and the activities of two enzymes associated with peroxisomes (catalase and the peroxisomal fatty acid beta-oxidation system) as well as cytosolic and microsomal epoxide hydrolase were measured. Microsomal epoxide hydrolase, cytosolic epoxide hydrolase and catalase activities were 7-12-fold…

The molecular basis of the low hemolytic activity of C4 molecules from low-C4 mice with IgM-coated erythrocytes.

1989

This study investigated the origin of the different hemolytic activity of two allotypes of murine C4, C4H (C4-high) and C4L (C4-low) in the presence of IgM-coated erythrocytes. C4H displayed a threefold higher hemolytic titer (expressed in hemolytic units/microgram protein) than C4L. No difference was found between c4H and C4L either in stability at 37 degrees C at different pH values and in the rate of C4H and C4L hydrolysis by activated Cl. The major functional difference was found in the covalent binding capacity to IgM-coated erythrocytes, with the amount of C4H bound being about threefold higher than that of C4L. A marked difference in the reactivity of the C4b fragment of C4H and C4L …

Replication of HSV-1 in murine peritoneal macrophages: comparison of various virus strains with different properties.

1984

The in vitro replication of eleven different strains of herpes simplex virus type 1 was studied in resident or thioglycollate-stimulated mouse macrophages. The strains of herpes simplex virus differed in the type of cytopathic effect, induction capacity for herpes simplex virus coded thymidine kinase and pathogenicity in the mouse. Herpes simplex virus replicated better in thioglycollate-stimulated macrophages than in resident macrophages. In vitro ageing of macrophages increased their replicative potency. Herpes simplex virus replicated better in macrophages from homozygous bg/bg C57/BL6J mice than in macrophages from their heterozygous littermates. Separation of macrophages on discontinuo…