Pathophysiology of melanocortin receptors and their accessory proteins.

The melanocortin receptors (MCRs) and their accessory proteins (MRAPs) are involved in regulation of a diverse range of endocrine pathways. Genetic variants of these components result in phenotypic variation and disease. The MC1R is expressed in skin and variants in the MC1R gene are associated with ginger hair color. The MC2R mediates the action of ACTH in the adrenal gland to stimulate glucocorticoid production and MC2R mutations result in familial glucocorticoid deficiency (FGD). MC3R and MC4R are involved in metabolic regulation and their gene variants are associated with severe pediatric obesity, whereas the function of MC5R remains to be fully elucidated. MRAPs have been shown to modulate the function of MCRs and genetic variants in MRAPs are associated with diseases including FGD type 2 and potentially early onset obesity. This review provides an insight into recent advances in MCRs and MRAPs physiology, focusing on the disorders associated with their dysfunction

Theoretical Analysis of Possible Martensitic Phases in Titanium Nickelide

The concept of co-operative thermal vibrations in crystals is applied here for an independent analysis of a system of martensitic phase transitions in titanium nickelide (NiTi). In addition to the orthorhombic B19 phase, which is well known for NiTi, a trigonal and a monoclinic phase - have been produced and are analyzed in detail. The calculated and experimental neutron diffraction patterns obtained for monoclinic and trigonal phases show a good agreement. The obtained structure of the monoclinic phase is absolutely different from the B19' structure described in the literature. Finally, more emphasis is placed on some complicated problems associated with a detailed identification of the trigonal phase structure

Martensitic Transformations in TiNi Alloys with Ti3Ni4 Precipitates

The thermoelastic martensitic transformations in Ti49Ni51 and Ti48Ni52 alloys after isothermal aging have been studied by means of transmission electron microscopy and dilatometry. The presence of Ti3Ni4 precipitates and the difference in precipitates size affect the martensite nucleation and martensitic transformation temperatures and sequences in TiNi alloys. Highly coherent and densely dispersed Ti3Ni4 particles (≤20-50 nm length) afrer initial aging stages depresses B2 → B19' transition and initiates B2 → R one. The Ti3Ni4 particles provide the nucleation sites for the R-martensite. When size of Ti3Ni4 particles run from 100 nm to I-2 µm, decreasing of number of Ti3Ni4 variants and thus R-phase ones is observed. Transformation sequence is B2 → R → B19'. When sizes of Ti3Ni4 particles run as large as several microns, they provide nucleation sites of the B19'-martensite. Transformation sequence is B2 → B19' as in solution treated specimen

Peculiarities of Thermoelastic Martensitic Transformation in the Cu-Zn-Al and Cu-Zn-Al-V after Decomposition of the β-Solid Solution

Dilatometric, metallographic, and electron-microscopic methods were used to study martensitic transformations in Cu-Zn-Al alloys that were subjected to a heat treatment to the decomposition of β solid solution at temperatures of α-phase precipitation (635-530°C) and bainite formation (300-125 °C). The partial decomposition and the accompanying redistribution of the components were shown to alter the type of martensitic transformation from nonthermoelastic to thermoelastic with a corresponding change in the martensite morphology from plate type to needle type (spear-shaped). A decrease in the temperature of isothermal anneal in the α+β range from 600 to 530°C substantially decrease the Ms temperature (by 140 °C). The temperature hysteresis of the transformation changes from 0 to 70 K

Formations theory in soviet school textbooks on general history [Teoría de las formaciones en libros de texto escolares soviéticos sobre historia general]

The purpose of the article is to analyze the Soviet experience of representing the world's historical process in the framework of the theory of changing social formations via the content analysis of Soviet school textbooks in relation to the formations-based structuring of history. As a result, the idea of a proletarian revolution was, according to the authors of textbooks, replaced by a bet on petty-bourgeois forces. In conclusion, in the USSR it was possible to create an integral model of systematic historical education in schools that allows solving current ideological problems. © 2020, Universidad del Zulia. All rights reserved