Load Effects Inside NPP VVER-1000 Containment Wall Cross Section

Atomic Energy - In connection with the use of the SPZO-M modernized system for prestressing the NPP containment, it became necessary to determine the effect of loads inside the containment wall on...     

Endocytosis in the mouse oocyte and its contribution to cAMP signaling during meiotic arrest

Mammalian oocytes are arrested at prophase I of meiosis until a preovulatory surge of LH stimulates them to resume meiosis. Prior to the LH surge, high levels of cAMP within the oocyte maintain meiotic arrest; this cAMP is generated in the oocyte through the activity of the constitutively active, G(s)-coupled receptor, G-protein-coupled receptor 3 (GPR3) or GPR12. Activated GPRs are typically targeted for desensitization through receptor-mediated endocytosis, but a continuously high level of cAMP is needed for meiotic arrest. The aim of this study was to examine whether receptor-mediated endocytosis occurs in the mouse oocyte and whether this could affect the maintenance of meiotic arrest. We found that constitutive endocytosis occurs in the mouse oocyte. Inhibitors of receptor-mediated endocytosis, monodansylcadaverine and dynasore, inhibited the formation of early endosomes and completely inhibited spontaneous meiotic resumption. A red fluorescent protein-tagged GPR3 localized in the plasma membrane and within early endosomes in the oocyte, demonstrating that GPR3 is endocytosed. However, overexpression of G-protein receptor kinase 2 and β-arrestin-2 had only a modest effect on stimulating meiotic resumption, suggesting that these proteins do not play a major role in GPR3 endocytosis. Inhibition of endocytosis elevated cAMP levels within oocytes, suggesting that there is an accumulation of GPR3 at the plasma membrane. These results show that endocytosis occurs in the oocyte, leading to a decrease in cAMP production, and suggest that there is a balance between cAMP production and degradation in the arrested oocyte that maintains cAMP levels at an appropriate level during the maintenance of meiotic arrest.     

Discriminating biomolecules with coherent control strategies

The activity of the GAP-Biophotonics research group at the University of Geneva in the field of coherent control for discriminating similar biomolecules, such as flavins, proteins and DNA bases, is presented and future developments are discussed.     

Multifunctional controller based on a power electronic converter

A multifunctional controller based on a power electronic converter is considered. The controller compensates the nonactive power in three-phase power-supply systems and performs the following functions; regulation of the reactive power, active filtration, and load balancing. By these means, it improves the power quality in low-voltage distribution systems. Control algorithms for the unit are considered. They are based on conversion of the signals from three-phase stationary coordinates to a two-phase rotating (synchronous) coordinate system (abc/dq transformation). The converter is controlled on the basis of sinusoidal pulse-width modulation. A MatLab/Simulink model is developed to study controller operation and the effectiveness of the proposed algorithms. The results of simulation are presented for different operational modes: reactive-power compensation; filtration of higher grid-current harmonics; current compensation with an unbalanced load; and complete compensation of the nonactive power with a nonlinear unbalanced load.     

Technological value of coal. 1. Clinkering coal

The concept of technological value is discussed. On that basis, a method of assessing the technological value of coal is recommended. The technological value of the basic clinkering coal in coking batch (Zh, GZh coal) is assessed. Similar estimates are presented for poorly coking GZhO and Zh coal, with somewhat inferior clinkering properties. Three levels of technological value are identified for clinkering coal: the first level includes Zh and GZh coal from enterprises in the Kuznets and Pechorsk basins; the second includes GZhO coal from the Raspadskaya and Vorgashorskaya mines; and the third includes G coal from the Kirov mine. GZhO and G coal from other enterprises in the Kuznets Basin does not function as clinkering coal.     

About the geometry of asymmetric fiber orientation distributions

Fiber orientation distributions (FODs) based on diffusion-sensitized magnetic resonance imaging are usually symmetric, primarily due to the nature of the diffusion. In contrast, the underlying fiber configurations are not, as bending or fanning configurations are inherently asymmetric. We propose to dismiss the symmetry of the FOD to additionally encode the asymmetry of the underlying fiber configuration. This is of particular importance for low resolution images that are common in diffusion weighted imaging. We set up the mathematical foundations and geometric interpretations of asymmetric FODs and show how one can benefit from these considerations. We infer a continuity condition that is used as a prior during FOD estimation by constrained spherical deconvolution. This new prior shows superior performance in comparison to other spatial regularization strategies in reliability and accuracy.     

Liquid luminophores POCl3-SiCl4-235UO 2 2+ -Nd3+

Samples of liquid luminophores POCl₃-SiCl₄-Nd³⁺, POCl₃-SiCl₄-²³⁵UO ₂ ²⁺ , and POCl₃-SiCl₄-²³⁵UO ₂ ²⁺ Nd³⁺ were prepared for the first time. The physicochemical properties and absorption spectra of the samples were compared. The solubility of Nd and U(VI) compounds in the POCl₃ SiCl₄ binary solvent was examined. The Nd³⁺ concentration attains a maximum of 0.3 mM when Nd and U(VI) trifluoroacetates are jointly dissolved at the [POCl₃]/[SiCl₄] molar ratio of 6 8. The shapes of the absorption band of the Nd ions at 860–900 nm, corresponding to the ⁴ I _9/2 → ⁴ F _3/2 electronic transition, differ significantly in POCl₃-SiCl₄-Nd³⁺ and POCl₃-SnCl₄-Nd³⁺ solutions, and in POCl₃-SiCl₄-²³⁵UO ₂ ²⁺ -Nd³⁺ solutions the band shape also depends on the type of the Nd and U(VI) compounds introduced. The near-IR region of the absorption spectra of POCl₃-SiCl₄-²³⁵UO ₂ ²⁺ and POCl₃-SiCl₄-²³⁵UO ₂ ²⁺ -Nd³⁺ solutions contains absorption bands of the OH groups. The band intensity is analyzed in relation to the characteristics of the solutions. The Nd³⁺ luminescence lifetime τ in the luminophores synthesized was estimated at 70–20 μs.     

Thermal effects in mixtures of aluminum with polyvinyl chloride after plastic deformation under high pressure

PVC and mixtures of PVC with aluminum of different compositions were subjected to plastic deformation under a pressure of 0.5–3.0 GPa using setups of Bridgman anvil type. DSC data showed that ΔC _p in the polymer was doubled and T _c increased by 20°C. Chemical reactions occurred on the interfaces of freshly opened metal surface/polymer phase under pressure treatment in the mixtures. They were accompanied by formation of volatile and soluble products. When metal-polymer mixtures were heated under pressure after deformation, chemical reactions occurred in them starting at 40°C and reaching the maximum intensity in the temperature range of polymer transition from the vitreous to highly elastic state. Thermogravimetric studies of mixture samples of different compositions were carried out.