Evaluation of Shear and Tensile Bridging Characteristics of PVA Fibers Based on Bridging Law

Strain-Hardening Cementitious Composites (SHCC), in which short fibers are mixed in mortar, show improved tensile performance and ductility of the cementitious material because fibers bridging the crack transfer tensile forces after first cracking. It is considered that the stress field at the shear crack surface in the structural element under the shear force is a biaxial stress field in which tensile and shear stresses exist concurrently. In fiber-reinforced cementitious composites, both tensile and shear stresses are transmitted via fibers that bridge shear cracks. It is necessary that the effect of fibers bridging a shear crack under tensile and shear stresses is investigated. In this study, uniaxial tension tests were carried out for specimens which have a square cross-section and an inclined notch. The biaxial stress field can be expressed by the inclined crack surface produced by the tensile loading. From the test results, it was confirmed that the tensile stress decreased with increasing notch angle in the tension tests. A calculation method for the bridging law with an inclined crack was introduced and the calculation results were compared with the test results. Though the maximum tensile stress in the tests was smaller than that in the calculation results, the curves after the maximum stress show good agreements with the calculations. The maximum stress reached in the tests tends to decrease with increasing crack angle (notch angle) as in the calculation results

Use of Antioxidant Substances in Intestinal Anastomosis in Rats

Introduction: Intestinal anastomosis consist of surgical procedures which there is an anastomotic line between two intestinal segments in order to reconstruct or divert the digestive transit. However, several complications may result from this surgical procedure. Objective: Present, describe and discuss the findings of the literature regarding substances capable of reducing injury and possible complications of intestinal anastomoses. Method: The data were collected by literature review using the descriptors: "intestinal anastomoses", "antioxidants"; and as basis articles published in the published Scientific Electronic Library (Scielo), Lilacs, MedLine and Pubmed databases. Inclusion criteria were original and review articles published in full in the online form in the Portuguese, Spanish and English languages, using the descriptors mentioned above in the respective languages. Results: Scientific articles were collected, in which 38 papers were included in the inclusion criteria. Conclusions: The major parts of substances described in the present study demonstrated be statistically relevant results and the capacity to optimize the anastomotic healing

Prioritisation of pharmaceuticals based on risks to aquatic environments in Kazakhstan

Over the last 20 years, there has been increasing interest in the occurrence, fate, effects and risk of pharmaceuticals in the natural environment. However, we still have only limited or no data on ecotoxicological risks of many of the active pharmaceutical ingredients (APIs) currently in use. This is partly due to the fact that the environmental assessment of an API is an expensive, time-consuming and complicated process. Prioritisation methodologies, that aim to identify APIs of most concern in a particular situation, could therefore be invaluable in focusing experimental work on APIs that really matter. The majority of approaches for prioritising APIs require annual pharmaceutical usage data. These methods cannot therefore be applied to countries, such as Kazakhstan, which have very limited data on API usage. This paper therefore presents an approach for prioritising APIs in surface waters in information-poor regions such as Kazakhstan. Initially data were collected on the number of products and active ingredients for different therapeutic classes in use in Kazakhstan and on the typical doses. These data were then used alongside simple exposure modelling approaches to estimate exposure indices for active ingredients (about 240 APIs) in surface waters in the country. Ecotoxicological effects data were obtained from the literature or predicted. Risk quotients were then calculated for each pharmaceutical based on the exposure and the substances ranked in order of risk quotient. Highest exposure indices were obtained for benzylpenicillin, metronidazole, sulbactam, ceftriaxone and sulfamethoxazole. The highest risk was estimated for amoxicillin, clarithromycin, azithromycin, ketoconazole and benzylpenicillin. In the future, the approach could be employed in other regions where usage information are limited. This article is protected by copyright. All rights reserved