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The objective of this study was to examine the influence of grain refinement on fatigue performance of Cu-2.5Ni-0.5Si-0.06Mg alloy (hereinafter referred to as CuNi3Si1Mg). The results indicate that the fatigue strength of the ultrafine-grained (UFG) CuNi3Si1Mg is about 1.6 times higher than the fatigue strength of the coarse-grained (CG) CuNi3Si1Mg. A detailed investigation of the fracture surfaces using scanning electron microscopy (SEM) showed that the initial microstructure affects the fatigue crack nucleation mechanism. In CG CuNi3Si1Mg, the cracks originated from the activated slip bands, while in UFG CuNi3Si1Mg, the cracks nucleated from the slip bands and twin boundaries. [ABSTRACT FROM AUTHOR]

Abstract: The main aim of the international UNECE monitoring program ICP Waters under the Convention of Long-range Transboundary Air Pollution (CLRTAP) is to assess, on a regional basis, the degree and geographical extent of the impact of atmospheric pollution, in particular acidification, on surface waters. Regional trends are calculated for 12 geographical regions in Europe and North America, comprising 189 surface waters sites. From 1990–2001 sulphate concentrations decreased in all but one of the investigated regions. Nitrate increased in only one region, and decreased in three North American regions. Improvements in alkalinity and pH are widely observed. Results from the ICP Waters programme clearly show widespread improvement in surface water acid-base chemistry, in response to emissions controls programs and decreasing acidic deposition. Limited site-specific biological data suggest that continued improvement in the chemical status of acid-sensitive lakes and streams will lead to biological recovery in the future. [Copyright &y& Elsevier]

This study estimates the effects of grain refinement on the transformation kinetics of precipitates as well as the development of mechanical properties and electrical conductivity of CuNi3Si1Mg. During aging at 450 °C, the mechanical behaviors of coarse-grained (CG) CuNi3Si1Mg and ultrafine-grained (UFG) CuNi3Si1Mg were studied and the Avrami-equations of phase transformation kinetics and electrical conductivity were analyzed. For both the conditions, the maximum strength was observed at 6 and 12 h, for UFG and CG CuNi3Si1Mg, respectively. According to the transformation kinetics curves of CG and UFG CuNi3Si1Mg, over aging reduced the growth rate of precipitates and affected their coarsening, resulting in decreased strength. [ABSTRACT FROM AUTHOR]

A potential impact of PGT-A on embryo implantation is often discussed in the reproduction of elderly women with a higher risk of oocyte aneuploidy while its impact is belied in women under 35 years at the same time. The authors studied the influence of PGT-A in egg donation program where the advanced reproductive age and potential oocyte incompetence is mostly excluded. In total, 246 embryos were thawed and transferred in egg donation patients of the age category 35 plus in period January 2017 – December 2018. Group A consists of 188 patients with a comprehensive aneuploidy screening (PGT-A), group B consists of 58 patient with no PGT-A. There were performed elective single embryo transfers solely in both groups. In group A an implantation rate was 46% (86/188) while in group B 20%(12/58). Natural cycles with triggering ovulation were more successful than the HRT ones (IR 53% resp. 44%). The results showed that PGT-A and transfer of euploid embryo improve an implantation rate in egg donation program in the age category 35 plus what is usually disregarded. The number of cycles to pregnancy was lower in case of a euploid embryo was transferred. The major factors involving the implantation rate besides the embryo quality and euploidy are an appropriate endometrial quality and striking the window of implantation (WOI). The implantation rate is slightly better in natural cycles compared to HRT (hormonal replacement treatment) cycles. Among other factors, we reached better results using a longer progesterone administration (minimum 5 days) and a time-lapse monitoring system used in synergy with an embryo selection for the biopsy. [ABSTRACT FROM AUTHOR]