Modified sperm stress test: a simple assay that predicts sperm-related abnormal in-vitro fertilization

Loss of sperm motility is associated with the process of sperm senescence and occurs at different rates within a given normal or abnormal sperm population. Reactive oxygen species attack cell membrane phospholipids, generating fatty acid peroxides and other degradation products, that also have deleterious effects on sperm motility and fertilizing ability. The objective of this investigation was to study a modification of the original sperm stress test (MOST), changing the culture medium to one offering transitional metals and shortening the total test time, to ascertain whether it can predict fertilization under these laboratory conditions. A total of 41 semen samples was obtained from patients undergoing in-vitro fertilization (IVF) at our institution. Semen samples were grouped into those producing total fertilization rates (FR) within normal limits (>50%) and those showing low total FR (<50%). The normal FR group had a significantly greater MOST mean value than the low FR group (0.71 versus 0.44). Furthermore, there was a statistically significant correlation between the MOST score and ungrouped fertilization rates (r = 0.53, P = 0.0004). Diagnostic statistics for MOST ratio values predicting <50% FR showed an optimal threshold of 0.39. Collectively, sensitivity, specificity, positive predictive value and negative predictive value have their largest values at this threshold. Taking into account the above mentioned threshold figures, there is a significant association between MOST and FR categories (P = 0.0009). In conclusion, MOST is a simple assay that has significant predictive value for sperm related IVF abnormalities.     

Dynamic event trees in accident sequence analysis: application to steam generator tube rupture

A dynamic event tree method for analyzing the risk associated with dynamic nuclear power plant accident sequences is presented. The method provides a framework for treating stochastic variations in operating crew states (defined by substrates characterizing the accident diagnosis, the planned actions, and the crew quality) as well as stochastic variations in hardware states. Plant process variables are treated deterministically; they are used when determining the likelihood of stochastic branchings. The method is used in an analysis of a steam generator tube rupture (SGTR) accident; it is shown that a number of important operator behavior patterns can be reasonably represented, and that, comparing with conventional event trees, sources of dependencies between failure events can be better defined.     

Hemorrhagic and edema-forming activity and histologic changes in the mouse footpad induced by venoms from Argentinian Bothrops and Crotalus genuses

Hemorrhagic, oedema-forming activities and histopathological alterations in the mouse footpad induced by Bothrops and Crotalus snake venoms from Argentina. Hemorrhagic and oedema-forming activities of various Bothrops and Crotalus snake venoms from Argentina were studied, together with histological alterations in the mouse footpad. The highest oedema-forming activity was found in the venom of B. jararaca, followed by B. jararacussu, B. neuwiedii diporus, B. alternatus, and Crotalus durissus terrificus. Regarding hemorrhage, the highest activity was found in the venom of B. neuwiedii diporus, followed by B. jararacussu, B. alternatus, and B. jararaca. No hemorrhage was observed after injection of Crotalus durissus terrificus venom, in agreement with histological observations of injected footpads. Histological analysis revealed a conspicuous inflammatory reaction in the injected footpad, characterized by oedema and an inflammatory infiltrate rich in polymorphonuclear leucocytes. Necrotic blood vessels and dilated lymphatic vessels were observed after injection of B. jararaca and B. jararacussu venoms, and myonecrosis was evident in tissue of mice injected with B. alternatus and B. neuwiedii diporus.     

Response to thermal treatment of a powder metallurgy Fe-0.8 % B-1.3 % C-1.6 %Cr alloy

Argon atomized powders of the Fe-0.8%B-1.3%C-1.6%Cr alloy in the rapid solidification condition as well as the consolidated material were characterized. Consolidation was carried out by extrusion at 1050°C and by hot isostatic pressing at 700°C. The microstructure of powder particles in the rapid solidification condition is dendritic and remains unchanged after hot isostatic pressing. This microstructure is gradually lost after annealing at temperatures above 900°C. The extruded material presents a fine and homogeneous microstructure constituted by small grains of laminar pearlite and spherical M₂₃(B,C)₆ borocarbides of 1.8 μm in size. A martensite microstructure with a uniform dispersion of M₃(B,C) borocementite particles is obtained after annealing at 1095°C 10 min and water quenching. For long austenitization time at 1095°C, a coalescence of borocementite as well as decarburization is observed in the steel. Dilatometric studies, between 20 and 400°C, of samples quenched from 1095°C show the presence of two contraction volume points at 160 and 310°C. At 160°C, the high carbon martensite decomposes into a two phase mixture of metastable carbides and low carbon martensite. At 310°C simultaneous transformation of austenite to ferrite and metastable carbides into cementite occurs.     

Morphological,structural, and interfacial changes produced in composites on the basis of polypropylene and surface-treated sepiolite with organic acids II. Thermal properties

Heat capacity and thermal expansion measurements in composites have been relatively little used as research procedures. In recent times, however, they are beginning to be increasingly utilized in morphological studies. This motivated the application of both techniques to composites on the basis of polypropylene and sepiolite that had been surface treated with linear organic acids. Assessment of our results allows for the interference that the incorporation of these sepiolites produces important structural changes in the polypropylene containing them. These changes can be explained by the complex interface (mesophase) theory.     

Preparation and Characterization of Conducting Systems based on EPDM/PE/PS‐co‐DVB/HSb

Summary: Blends of different compositions were prepared from: a thermoplastic elastomer (EPDM), a low density polyethylene (PE), a polystyrene crosslinked with a small amount of divinylbenzene (PS‐co‐DVB) and an inorganic proton conductor: antimonic acid (HSb). The blends obtained were sulfonated heterogeneously with chlorosulfonic acid and were then structurally and electrically characterized by means of the following techniques: differential scanning calorimetry (DSC), dynamic mechanical analysis (DMA), crystallization kinetics under non‐isothermal conditions and complex impedance spectroscopy.

Dynamic mechanical analysis for EPDM and EP‐3 blends series.     

Preparation and characterization of hybrid thiol‐ene/epoxy UV–thermal dual‐cured systems

Hybrid thiol‐ene/epoxy coatings were prepared by combining thiol‐ene photo‐curable formulations with epoxy monomers, through a dual UV–thermal curing process. An increase in glass transition temperature and in storage modulus was observed for the hybrid thiol‐ene/epoxy coatings when compared with the pristine thiol‐ene UV‐cured system. Also, the bisphenol A moieties introduced into the hybrid networks during the dual‐curing process induced an increase in thermal stability of the cured materials. It has been demonstrated that the addition of epoxy monomer to the thiol‐ene photo‐curable system is a good strategy to follow in order to improve the final properties of thiol‐ene‐based coatings leading to a wide range of possible applications for the hybrid materials. Copyright © 2010 Society of Chemical Industry