Pharmacogenetics of antiretroviral drugs

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Postexposure prophylaxis against hepatitis B, hepatitis C and human immunodeficiency virus infection in healthcare workers

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The Effect of Water Concentration in Ethyl Alcohol on the Environmentally Assisted Embrittlement of Austempered Ductile Irons

Austempered ductile iron (ADI) is an advanced cast iron material that has a broad field of application and, among others, it is used in contact and for conveyance of fluids. However, it is noticed that in contact with some fluids, especially water, ADI material becomes brittle. The most significant decrease is established for the elongation. However, the influence of water and the cause of this phenomenon is still not fully understood. For that reason, in this paper, the influence of different water concentrations in ethyl alcohol on the mechanical properties of ADI materials was studied. The test was performed on two different types of ADI materials in 0.2, 4, 10, and 100 vol.% water concentration environments, and in dry condition. It was found that even the smallest concentration of water (0.2 vol.%) causes formation of the embrittled zone at fracture surface. However, not all mechanical properties were affected equally and not all water concentrations have been critical. The highest deterioration was established in the elongation, followed by the ultimate tensile strength, while the proof strength was affected least

Tensile properties of ADI material in water and gaseous environments

Austempered ductile iron (ADI) is an advanced type of heat treated ductile iron, having comparable mechanical properties as forged steels. However, it was found that in contact with water the mechanical properties of austempered ductile irons decrease, especially their ductility. Despite considerable scientific attention, the cause of this phenomenon remains unclear. Some authors suggested that hydrogen or small atom chemisorption causes the weakening of the surface atomic bonds. To get additional reliable data of that phenomenon, in this paper, two different types of austempered ductile irons were tensile tested in various environments, such as: argon, helium, hydrogen gas and water. It was found that only the hydrogen gas and water gave a statistically significant decrease in mechanical properties, i.e. cause embrittlement. Furthermore, the fracture surface analysis revealed that the morphology of the embrittled zone near the specimen surface shares similarities to the fatigue micro-containing striation-like lines, which indicates that the morphology of the brittle zone may be caused by cyclic local-chemisorption, micro-embrittlement and local-fracture. (C) 2015 Elsevier Inc. All rights reserved

Safety of antiretrovirals in pregnacy

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Tensile properties of ADI material in water and gaseous environments

Austempered ductile iron (ADI) is an advanced type of heat treated ductile iron, having comparable mechanical properties as forged steels. However, it was found that in contact with water the mechanical properties of austempered ductile irons decrease, especially their ductility. Despite considerable scientific attention, the cause of this phenomenon remains unclear. Some authors suggested that hydrogen or small atom chemisorption causes the weakening of the surface atomic bonds. To get additional reliable data of that phenomenon, in this paper, two different types of austempered ductile irons were tensile tested in various environments, such as: argon, helium, hydrogen gas and water. It was found that only the hydrogen gas and water gave a statistically significant decrease in mechanical properties, i.e. cause embrittlement. Furthermore, the fracture surface analysis revealed that the morphology of the embrittled zone near the specimen surface shares similarities to the fatigue micro-containing striation-like lines, which indicates that the morphology of the brittle zone may be caused by cyclic local-chemisorption, micro-embrittlement and local-fracture

Effect of oxytocin as a partial agonist at vasoconstrictor vasopressin receptors on the human isolated uterine artery

The effect of oxytocin on endothelium-intact and endothelium-denuded segments of the human uterine artery rings was investigated. In both types of preparation oxytocin induced contraction of human uterine artery with similar potency and efficacy (pEC(50) values: 6.95±0.05 vs 7.06±0.01; maximal response values: 61±4.1% vs 63±5.1% for arteries with and without endothelium, respectively). In contrast, human uterine arteries, both intact and denuded of endothelium, did not respond to the addition of the selective oxytocin receptor agonist, [Thr(4), Gly(7)]oxytocin (10 nM–1 μM). The vasopressin receptor antagonists, [d(CH(2))(5)Tyr(Me)]AVP (10–100 nM) and [d(CH(2))(5),D-Ile(2),Ile(4)]AVP (300 nM–3 μM) produced parallel rightward shifts of the curves for oxytocin. The Schild plots constrained to a slope of unity gave the following −log K(B) values: [d(CH(2))(5)Tyr(Me)] AVP vs [d(CH(2))(5),D-Ile(2),Ile(4)] AVP 9.24 vs 6.91 and 9.26 vs 6.84 for human uterine artery with intact and those denuded of endothelium, respectively. In contrast, in both types of preparations the oxytocin receptor antagonist, [d(CH(2))(5)Tyr(OMe), (2)Orn(8)]vasotocin (1 μM), did not significantly affect oxytocin-induced contractions. The calculated pK(A) values for oxytocin itself also did not differ between preparations: 6.56 and 6.43 for human uterine artery with and without endothelium, respectively. In both types of preparations, the receptor reserve (K(A)/EC(50)) was close to unity (intact vs denuded: 3.9 vs 3.0). It is concluded that, in human uterine artery, oxytocin induces contractions that are not modulated by the endothelium. It is likely that oxytocin acts as a partial agonist on human uterine artery, regardless of the endothelial condition. On the basis of differential antagonists affinity and affinity of oxytocin itself, it is probable that receptors involved in oxytocin-induced contraction in human uterine arteries belong to the V(1A) vasopressin receptors