Pleiotropic effects of a rel mutation on stress survival of Rhizobium etli CNPAF512

The rel gene of Rhizobium etli (relRet), the nodulating endosymbiont of the common bean plant, determines the cellular level of the alarmone (p)ppGpp and was previously shown to affect free-living growth and symbiosis. Here, we demonstrate its role in cellular adaptation and survival in response to various stresses.Journal ArticleResearch Support, Non-U.S. Gov'tinfo:eu-repo/semantics/publishe

Исследование эффективности брейкеров для жидкостей гидроразрыва пласта

Исследование влияния биоразлагаемых брейкеров на реологические характеристики жидкостей гидроразрыва пласта.Investigation of the effect of biodegradable breakers on the rheological characteristics of fracturing fluids

Co-culture of two-cell rat embryos on cell monolayers.

Monolayers of 2 different populations of uterine cells and of fetal fibroblasts were evaluated for the support of rat embryo development in vitro. Compared to controls, cultures performed in Earle's buffered saline solution (EBSS) alone, the cleavage rate of 2-cell embryos to the 4-cell stage was significantly increased when the embryos were cocultured for 24 h with mixed uterine stromal and myometrial cells (70.7 vs. 56.0%; P less than 0.01). Coculture of 2-cell embryos with either uterine epithelial-stromal or stromal-myometrial cells in medium TC 199 (M199) for 24 h significantly increased the cleavage rate to the 4-cell stage compared to controls in the same medium (respectively, 78.3 and 77.6 vs. 49.9%; P less than 0.01). The development was not improved when fibroblasts were used as feeder cells. After 48 h, the proportion of 4-cell embryos showing cellular fragmentation was significantly decreased in the presence of either epithelial-stromal or stromal-myometrial cells in M199 compared to controls (respectively, 18.4 and 20.0 vs. 43.8%; P less than 0.01). Coculture in EBSS or with fibroblasts failed to prevent embryo degeneration. In one coculture with stromal-epithelial cells in M199, 6/11 embryos proceeded beyond the 4-cell stage, two of them reaching the 8-cell stage. No embryo developed beyond that stage in our study. Although considerable efforts remain necessary to achieve further growth, these results suggest that coculture offers promise as a means of supporting the in vitro development of rat embryos

Decreased inner cell mass proportion in blastocysts from diabetic rats.

Late morulae and blastocysts were recovered from streptozocin-induced diabetic pregnant rats and individually examined for numbers of inner cell mass (ICM) cells and trophectoderm (TE) cells. Compared with embryos collected from control rats, exposure to maternal diabetes significantly decreased mean ICM cell number of blastocysts recovered on day 5 of gestation, but the TE population of these embryos remained unaffected. The mean ICM proportion was therefore significantly lower than that of control embryos. These differences were not observed between the two groups of morulae collected on day 5, suggesting that the distinctive susceptibility of the ICM was expressed after blastocyst formation. On day 6, a significant inhibitory effect of diabetes was observed on the growth of both ICM and TE cells, but because the reduction was more severe in the ICM than in the TE, the mean ICM proportion of these blastocysts was again significantly lower than in control embryos. A linear quadratic relationship was obtained between the numbers of ICM cells of individual blastocysts and their respective numbers of TE cells in each of the two experimental groups. However, the slope of the curve was slower in the diabetic group than the control group. The disturbed ICM cell growth in the blastocysts from diabetic rats was found to be associated with a significantly increased incidence of cell death predominantly located in the ICM. Because it is known that excessive reduction of the ICM is incompatible with normal embryogenesis after implantation, our results suggest that the differential sensitivity of ICM and TE cells in preimplantation blastocysts may contribute to the pattern of postimplantation defects described in diabetic pregnancies

High Energy Storage Density in Nanocomposites of P(VDF-TrFE-CFE) Terpolymer and BaZr_0.2Ti_0.8O₃ Nanoparticles

Polymer materials are actively used in dielectric capacitors, in particular for energy storage applications. An enhancement of the stored energy density can be achieved in composites of electroactive polymers and dielectric inorganic fillers with a high dielectric permittivity. In this article, we report on the energy storage characteristics of composites of relaxor terpolymer P(VDF-TrFE-CFE) and BaZr0.2Ti0.8O3 (BZT) nanoparticles. The choice of materials was dictated by their large dielectric permittivity in the vicinity of room temperature. Free-standing composite films, with BZT contents up to 5 vol.%, were prepared by solution casting. The dielectric properties of the composites were investigated over a wide range of frequencies and temperatures. It was shown that the addition of the BZT nanoparticles does not affect the relaxor behavior of the polymer matrix, but significantly increases the dielectric permittivity. The energy storage parameters were estimated from the analysis of the unipolar polarization hysteresis loops. The addition of the BZT filler resulted in the increasing discharge energy density. The best results were achieved for composites with 1.25–2.5 vol.% of BZT. In the range of electric fields to 150 MV/m, the obtained materials demonstrate a superior energy storage density compared to other P(VDF-TFE-CFE) based composites reported in the literature