In this research the stress-strain curve of porous Titanium, as a common material for biomedical application, was predicted using the mechanical properties of fully solid Titanium experimental data. Modified Gurson model (Gurson-Tvergaard-Needleman (GTN) model) was used to predict the plastic response of porous Titanium in compaction. Different values of GTN parameters were used for different i...

In this paper the capability of Gurson-Tvergaard-Needleman (GTN) model in the prediction of ductile damage in 7075-T651 aluminum alloy is investigated. For this purpose, three types of specimens were tested: Standard tensile bars, Round notched bar (RNB) specimens and compact tension (C(T)) specimens. Standard tensile bar tests were used to obtain the mechanical properties of the material and t...

Nitroglycerin (GTN) has been used to treat heart disease for many years. It is generally believed that GTN is a prodrug; however, the mechanism for GTN bioactivation remains unknown. Recent studies, using hepatic microsomes, have suggested the involvement of cytochrome P450 3A (CYP3A) in GTN biotransformation. Here, we used an animal model to test the hypothesis that aortic CYP3A plays a role i...

Damage and dysfunction of the vascular endothelium critically influence clinical outcomes after ischemia and reperfusion (I/R). Brief exposure to organic nitrates can protect the vascular endothelium from I/R injury via a mechanism that is similar to ischemic preconditioning and is independent of hemodynamic changes. The clinical relevance of these protective effects clearly depends on whether ...

The present work addresses the micromechanical modeling and simulation of crack initiation propagation in ductile materials failing by void nucleation, growth coalescence. A cohesive–volumetric approach is used overall material behavior characterized both a hardening bulk constitutive law softening surface traction–separation embedded between each mesh finite element discretization. sums up acr...

An experimental model of headache offers unique possibilities to study the mechanisms responsible for head pain. Using the glyceryl trinitrate [GTN; nitric oxide (NO) donor] model of experimental headache, we studied the intensity, quality and time profile of headache after infusion of GTN in 16 patients with chronic tension-type headache and in 16 healthy controls. Subjects were randomized to ...

Bioactivation of nitroglycerin (GTN) into an activator of soluble guanylate cyclase (sGC) is essential for the vasorelaxant effect of the drug. Besides several enzymes that catalyze GTN bioactivation, the reaction with cysteine is the sole nonenzymatic mechanism known so far. Here we show that a reaction with ascorbate results in GTN bioactivation. In the absence of ascorbate, GTN did not affec...

BACKGROUND Topical application of glyceryl trinitrate (GTN) ointment heals chronic anal fissures, providing an alternative to the traditional first line treatment of surgical sphincterotomy. AIMS To determine the most effective dose of topical GTN for treatment of chronic anal fissures and to assess long term results. METHODS Seventy consecutive patients with chronic anal fissure, were rand...