Interface chemistry and epitaxial growth modes of SrF2 on Si(001)

Molecular beam epitaxy has been used to grow SrF2 thin films on Si(001). The growth modes have been investigated by atomic force microscopy, electron diffraction, and photoemission. Two principal growth regimes have been identified: (i) when deposition is carried out with the substrate held at a temperature of 700-750 degrees C, SrF2 molecules react with the substrate giving rise to a Sr-rich wetting layer on top of which three dimensional bulklike fluoride ridges develop; (ii) when deposition is carried out with the substrate held at 400 degrees C, a nanopatterned film forms with characteristic triangular islands. Results are compared to the growth mode of CaF2 on Si(001) under analogous deposition conditions. Morphological and structural differences between the two systems are associated with the larger lattice parameter of SrF2 with respect to CaF2, resulting in a larger mismatch with the Si substrate

Structural peculiarities of ε\varepsilon-Fe2_2O3_3 / GaN epitaxial layers unveiled by high-resolution transmission electron microscopy and neutron reflectometry

The present paper is dedicated to the structural study of crystallographic peculiarities appearing in epitaxial films of metastable epsilon iron oxide ($\varepsilon$-Fe$_2$O$_3$) grown by pulsed laser deposition onto a semiconductor GaN (0001) substrate. The columnar structure of the nanoscale $\varepsilon$-Fe$_2$O$_3$ films has been for the first time investigated using high resolution electron microscopy (HRTEM) direct space technique complemented by reciprocal space methods of high-energy electron diffraction and color-enhanced HRTEM image Fourier filtering. The study of $\varepsilon$-Fe$_2$O$_3$ / GaN interface formation has been further expanded by carrying out a depth resolved analysis of density and chemical composition by neutron reflectometry and energy-dispersive X-ray spectroscopy. The obtained results shed light onto the properties and the origin of the enigmatic few-nanometer thick low density transition layer residing at the $\varepsilon$-Fe$_2$O$_3$ / GaN interface. A detailed knowledge of the properties of this layer is believed to be highly important for the development of $\varepsilon$-Fe$_2$O$_3$ / GaN heterostructures that can potentially become part of the iron-oxide based ferroic-on-semiconductor devices with room temperature magneto-electric coupling.Comment: 14 pages, 9 figure

ПРИМЕНЕНИЕ АВТОМАТИЗИРОВАННОЙ ИНФОРМАЦИОННО-АНАЛИТИЧЕСКОЙ СИСТЕМЫ МОНИТОРИНГА ПОДГОТОВКИ НАУЧНЫХ РАБОТНИКОВ ВЫСШЕЙ КВАЛИФИКАЦИИ ДЛЯ АНАЛИЗА ДИНАМИКИ РАЗВИТИЯ ПОСЛЕВУЗОВСКОГО ОБРАЗОВАНИЯ В РЕСПУБЛИКЕ БЕЛАРУСЬ

The possibilities of the automated information-analytical system for monitoring the highest qualification scientific personnel training are presented. It is shown that the application of the above system allows to get information about the state of the highest qualification scientific personnel training in the Republic of Belarus, to perform the analysis of the dynamics of the postgraduate education development on a wide range of quantitative and qualitative indicators.Представлены возможности автоматизированной информационно-аналитической системы мониторинга подготовки научных работников высшей квалификации (АСМ НРВК). Показано, что применение АСМ НРВК позволяет получать оперативную информацию о состоянии подготовки научных работников высшей квалификации в Республике Беларусь, осуществлять анализ динамики развития послевузовского образования по широкому спектру количественных и качественных показателей

Comparative evaluation of surgical methods for low invasive surgical treatment of diseases of the kidneys and urinary tract

Background. The rapid development of laparoscopic surgery can significantly reduce trauma during operations in the retroperitoneal space. These goals are also achieved by retroperitoneoscopy (RPS), which has become widespread in the last twenty years. The main difficulties for surgeons were associated with a small workspace and a lack of clear anatomical landmarks. Different access methods have different features, advantages and disadvantages, the analysis of which helps to optimize surgical treatment and accelerate patient rehabilitation.Aim: to study the advantages and disadvantages of retroperitoneoscopic and transperitoneal laparoscopic surgical methods of treatment.Materials and methods: We analyzed 305  case histories of patients operated on for various kidney diseases. The patients were divided into 2 groups: Group 1 – patients who underwent surgery using an extraperitoneal retroperitoneoscopic approach, Group 2 – patients who used the transperitoneal laparoscopic approach. A comparison of two methods of surgical treatment of kidney diseases, retroperitoneoscopic and laparoscopic access, was carried out. The following indicators were compared: duration of surgery, length of hospital stay, need for analgesics, frequency of postoperative complications.Results. The duration of the operation with retroperitoneoscopic surgery was reduced by more than 15 % compared with the laparoscopic approach. Shorter periods of pain relief were required, and the number of complications also decreased. The duration of inpatient treatment did not differ significantly.Conclusion. Retroperitoneoscopic approach can be used as the method of choice for operations on the retroperitoneal space

Role of gallium diffusion in the formation of a magnetically dead layer at the Y3Fe5O12/Gd3Ga5O12 epitaxial interface

We have clarified the origin of a magnetically dead interface layer formed in yttrium iron garnet (YIG) films grown at above 700 degrees C onto a gadolinium gallium garnet (GGG) substrate by means of laser molecular beam epitaxy. The diffusion-assisted formation of a Ga-rich region at the YIG/GGG interface is demonstrated by means of composition depth profiling performed by x-ray photoelectron spectroscopy, secondary ion mass spectroscopy, and x-ray and neutron reflectometry. Our finding is in sharp contrast to the earlier expressed assumption that Gd acts as a migrant element in the YIG/GGG system. We further correlate the presence of a Ga-rich transition layer with considerable quenching of ferromagnetic resonance and spin wave propagation in thin YIG films. Finally, we clarify the origin of the enigmatic low-density overlayer that is often observed in neutron and x-ray reflectometry studies of the YIG/GGG epitaxial system

Perilipin 5 Deletion Unmasks an Endoplasmic Reticulum Stress-Fibroblast Growth Factor 21 Axis in Skeletal Muscle.

Lipid droplets (LDs) are critical for the regulation of lipid metabolism, and dysregulated lipid metabolism contributes to the pathogenesis of several diseases, including type 2 diabetes. We generated mice with muscle-specific deletion of the LD-associated protein perilipin 5 (PLIN5, Plin5MKO ) and investigated PLIN5's role in regulating skeletal muscle lipid metabolism, intracellular signaling, and whole-body metabolic homeostasis. High-fat feeding induced changes in muscle lipid metabolism of Plin5MKO mice, which included increased fatty acid oxidation and oxidative stress but, surprisingly, a reduction in inflammation and endoplasmic reticulum (ER) stress. These muscle-specific effects were accompanied by whole-body glucose intolerance, adipose tissue insulin resistance, and reduced circulating insulin and C-peptide levels in Plin5MKO mice. This coincided with reduced secretion of fibroblast growth factor 21 (FGF21) from skeletal muscle and liver, resulting in reduced circulating FGF21. Intriguingly, muscle-secreted factors from Plin5MKO , but not wild-type mice, reduced hepatocyte FGF21 secretion. Exogenous correction of FGF21 levels restored glycemic control and insulin secretion in Plin5MKO mice. These results show that changes in lipid metabolism resulting from PLIN5 deletion reduce ER stress in muscle, decrease FGF21 production by muscle and liver, and impair glycemic control. Further, these studies highlight the importance for muscle-liver cross talk in metabolic regulation