AlGaN Heterostructure Optimization for Photodetectors

GaN-based photodetectors are of great interest for applications involving detection and imaging in the UV-visible wavelength range. Most of experimental and theoretical work in this area has been focused so far on Schottky diode and p-i-n structures for solar blind applications. However, it seems that bipolar phototransistors with their additional functionality could also be of potential interest. In this work we present the results of phototransistors parameters simulation using the software – Sim Windows. The structure analyzed consisted, counting from the substrate, of n-Al[x]Ga1 – [x]N collector, p-GaN base and n-Al[x]Ga1 – [x]N emitter. The Al mole fraction in the collector and emitter was varied from x = 0.2 to x = 0.3. The collector and emitter thickness was taken as 0.9 hm. The doping level in the emitter and collector was varied from 1017 to 1019 cm – 3. The p-GaN base thickness was taken as 0.3 m, with doping of 1017-1018 cm – 3. The electron and hole lifetimes in the base were taken as 12 ns

Applications of electrified dust and dust devil electrodynamics to Martian atmospheric electricity

Atmospheric transport and suspension of dust frequently brings electrification, which may be substantial. Electric fields of 10 kVm-1 to 100 kVm-1 have been observed at the surface beneath suspended dust in the terrestrial atmosphere, and some electrification has been observed to persist in dust at levels to 5 km, as well as in volcanic plumes. The interaction between individual particles which causes the electrification is incompletely understood, and multiple processes are thought to be acting. A variation in particle charge with particle size, and the effect of gravitational separation explains to, some extent, the charge structures observed in terrestrial dust storms. More extensive flow-based modelling demonstrates that bulk electric fields in excess of 10 kV m-1 can be obtained rapidly (in less than 10 s) from rotating dust systems (dust devils) and that terrestrial breakdown fields can be obtained. Modelled profiles of electrical conductivity in the Martian atmosphere suggest the possibility of dust electrification, and dust devils have been suggested as a mechanism of charge separation able to maintain current flow between one region of the atmosphere and another, through a global circuit. Fundamental new understanding of Martian atmospheric electricity will result from the ExoMars mission, which carries the DREAMS (Dust characterization, Risk Assessment, and Environment Analyser on the Martian Surface)-MicroARES (Atmospheric Radiation and Electricity Sensor) instrumentation to Mars in 2016 for the first in situ measurements

Physicochemical Characteristics of a Variant of Chaperon GroEL Apical Domain Designed to Enhance the Expression and Stability of Target Proteins

Abstract: This work describes the properties of a new protein, a modification of GroEL apical domain designed to be a leader in fusion systems. This polypeptide leader demonstrates a high level of expression in a bacterial system; it is soluble and retains its solubility during standard biochemical manipulations. The secondary structure of the protein and its thermostability, as well as the protein solubility, were studied in a wide temperature range. To simplify the subsequent purification of the target protein, the possibility of its chemical cleavage from the fused protein by methionine residues with cyanogen bromide is provided. © 2019, Pleiades Publishing, Inc

Physicochemical characteristics of modification of chaperon groel apical domain designed to enhance expression and stability of target proteins [Физико-химическая характеристика варианта апикального домена шаперона GroEL для повышения уровня биосинтеза и увеличения стабильности целевых белков]

Описаны свойства нового белка, являющегося вариантом апикального домена шаперона GroEL, предназначенного служить лидером при создании слитых белков. Данный полипептидный лидер демонстрирует высокий уровень биосинтеза в бактериальной системе, растворим и сохраняет растворимость после стандартных биохимических манипуляций. Исследована его вторичная структура и ее термостабильность, а также растворимость белка в широком диапазоне температур. Для упрощения процедуры последующей очистки целевого белка предусмотрена возможность его химического отщепления по остатку метионина под действием бромциана.The expression of heterologous proteins in bacterial system is often impeded or even impossible due, for instance, to their lability, hydrophobicity or toxicity. In many cases, the problem can be partially or completely solved by creating fusion proteins with a leader able to enhance the solubility or stability of a target protein. In this work, the properties of a new protein, a modification of GroEL apical domain, designed to be a leader in fusion systems have been described. This polypeptide leader demonstrates a high level of expression in the bacterial system; it is soluble and retains its solubility after standard biochemical manipulations. The secondary structure of the protein and its thermal stability, and also the protein solubility were studied in the wide temperature range. To simplify the following purification of the target protein, a possibility of its chemical cleavage from the fused protein at the methionine residues using cyan bromide is provided. © 2009-2017 State Research Institute for Genetics and Selection of Industrial

Investigation of gamma secretase gene complex mutations in German population with Hidradenitis suppurativa designate a complex polygenic heritage.

BACKGROUND: Hidradenitis suppurativa (HS) is a chronic inflammatory disease affecting apocrine gland-bearing skin in the axilla, groin and under the breasts. Mutations of the gamma-secretase gene complex, which is essential in the activation of Notch signalling pathways were shown in some families with HS and in a few sporadic cases. Although an imbalance in Notch signalling is implicated in the pathogenesis, the exact mechanism of HS development is yet unknown. OBJECTIVES: We aim to investigate the genetic basis of HS by determining the presence of mutations of gamma-secretase gene complex in a cohort of HS patients and by searching for a disease-causing pathogenic variant in a multi-generational HS family using parametric linkage analysis. METHODS: Thirty-eight patients clinically diagnosed with HS were included in this study. All exons and exon-intron boundaries of the genes encoding gamma-secretase complex consisting of six genes: APH1A, APH1B, PSENEN, NCSTN, PSEN1 and PSEN2 were sequenced by Sanger technique. Genetic mapping with parametric linkage analysis for the patients in the family was performed with eight affected and four healthy individuals. The logarithm of odds was calculated. RESULTS: In a sporadic patient with early-onset, severe lesions in axilla and groin, a novel single nucleotide deletion causing frameshift in exon 1 of the NCSTN gene was identified ((NM_015331.3): c.38delG, p.(Gly13Glufs*15)). The LOD score of 1.5 was never exceeded in any region of the genome, pointing towards intricate multigenic inheritance pattern within the affected family. CONCLUSIONS: The gamma-secretase gene complex mutations were rare in our cohort (3.2%). Besides, our analysis indicates a possible complex multigenic inheritance in a seemingly autosomal dominantly inherited large HS family. Genetics of both familial and sporadic HS may be complicated in most cases, and the role of other potential genes such as autoinflammatory and modifier genes as well as environmental factors may influence the pathogenesis