Thin superconductors and SQUIDs in perpendicular magnetic field

It is shown how the static and dynamic electromagnetic properties can be calculated for thin flat superconducting films of any shape and size, also multiply connected as used for SQUIDs, and for any value of the effective magnetic London penetration depth Lambda. As examples, the distributions of sheet current and magnetic field are obtained for rectangular and circular films without and with slits and holes, in response to an applied perpendicular magnetic field and to magnetic vortices moving in the film. The self energy and interaction of vortices with each other and with an applied magnetic field and/or transport current are given. Due to the long ranging magnetic stray field, these energies depend on the size and shape of the film and on the vortex position even in large films, in contrast to the situation in large bulk superconductors. The focussing of magnetic flux into the central hole of square films without and with a radial slit is compared.Comment: 12 pages, 10 figure

Lagrangian structures in time-periodic vortical flows

The Lagrangian trajectories of fluid particles are experimentally studied in an oscillating four-vortex velocity field. The oscillations occur due to a loss of stability of a steady flow and result in a regular reclosure of streamlines between the vortices of the same sign. The Eulerian velocity field is visualized by tracer displacements over a short time period. The obtained data on tracer motions during a number of oscillation periods show that the Lagrangian trajectories form quasi-regular structures. The destruction of these structures is determined by two characteristic time scales: the tracers are redistributed sufficiently fast between the vortices of the same sign and much more slowly transported into the vortices of opposite sign. The observed behavior of the Lagrangian trajectories is quantitatively reproduced in a new numerical experiment with two-dimensional model of the velocity field with a small number of spatial harmonics. A qualitative interpretation of phenomena observed on the basis of the theory of adiabatic chaos in the Hamiltonian systems is given. <br><br> The Lagrangian trajectories are numerically simulated under varying flow parameters. It is shown that the spatial-temporal characteristics of the Lagrangian structures depend on the properties of temporal change in the streamlines topology and on the adiabatic parameter corresponding to the flow. The condition for the occurrence of traps (the regions where the Lagrangian particles reside for a long time) is obtained

Dynamical effects of an unconventional current-phase relation in YBCO dc-SQUIDs

The predominant d-wave pairing symmetry in high temperature superconductors allows for a variety of current-phase relations in Josephson junctions, which is to a certain degree fabrication controlled. In this letter we report on direct experimental observations of the effects of a non-sinusoidal current-phase dependence in YBCO dc-SQUIDs, which agree with the theoretical description of the system.Comment: 4 pages, 4 ps figures, to apprear in Phys. Rev. Let

Inductance extraction of superconductor structures with internal current sources

The sheet current model underlying the software 3D-MLSI package for calculation of inductances of multilayer superconducting circuits, has been further elaborated. The developed approach permits to overcome serious limitations on the shape of the circuits layout and opens the way for simulation of internal contacts or vias between layers. Two models for internal contacts have been considered. They are a hole as a current terminal and distributed current source. Advantages of the developed approach are illustrated by calculating the spatial distribution of the superconducting current in several typical layouts of superconducting circuits. New meshing procedure permits now to implement triangulation for joint projection of all nets thus improving discrete physical model for inductance calculations of circuits made both in planarized and non-planarized fabrication processes. To speed-up triangulation and build mesh of better quality, we adopt known program "Triangle".Comment: 17 pages, 5 figure

New Method of Vaccination Against Anthrax

The aim of this work was to develop an oral method of vaccination against anthrax, since wide vaccination campaigns using this method require no special conditions, equipment, and instruments. Also, minimum number of medical personnel is sufficient to ensure control over the intake of the drug. Materials and methods. Domestic raw materials, consumables and reagents that passed the incoming inspection and met the requirements of State and industry standards, technical specifications, and the articles of the Pharmacopoeia were used for the work. Batches of anthrax vaccines based on Bacillus anthracis strain STI-1, manufactured at the Research Center (Kirov) of the “48th Central Research Institute” of the Ministry of Defense of Russia were put to the test. Results and discussion. The immunization schemes have been tested on animals, taking into account the features of the antigen. One of the crucial factors that determine the effectiveness of oral vaccination is the correct choice of the type and form of the oral anthrax vaccine administered enterally. It has been shown that in contrast to oral vaccines, the vaccine strain in enteral vaccines must be protected from the harmful effects of stomach contents. Thus, enteric-coated capsules coated with a shell that is resistant to the action of stomach acid were used for the study. The presented experimental data indicate that a single administration of the capsules with oral anthrax vaccine STI protects at least 70 % of laboratory animals from a highly virulent strain of the anthrax microbe and confirm the safety and non-reactogenicity of the drug. The developed laboratory technology makes it possible to obtain a finished product containing one inoculation dose of an oral vaccine for laboratory animals. So, a new method of vaccination has been designed. It is necessary to conduct preclinical and clinical trials to promptly introduce the oral administration of anthrax vaccine into medical practice as the simplest method for mass vaccination of humans

Association of carotid atherosclerosis and peripheral artery disease in patients with type 2 diabetes: risk factors and biomarkers

BACKGROUND: Carotid atherosclerosis (CA) and lower extremity peripheral artery disease (PAD) is a common and potentially life-threatening comorbidity in diabetes.AIM: to determine risk factors and biomarkers of the association of CA and PAD in patients with type 2 diabetes.MATERIALS AND METHODS: A single-center cross-sectional comparative study was carried out. Three hundred ninety one patients with type 2 diabetes were included. Duplex ultrasound of carotid and low limb arteries, screening/monitoring of diabetic complications and associated diseases, and assessment of glycemic control, biochemical and coagulation parameters were performed. Factors involved in vascular wall remodeling, including calponin-1, relaxin, L-citrulline, matrix metalloproteinase-2 and -3, were measured in blood serum by ELISA.RESULTS: The signs of CA and PAD were observed in 330 and 187 patients respectively. In 178 patients, both CA and PAD were revealed. The risk of combined involvement of carotid and lower extremity arteries was higher in patients with diabetic retinopathy (OR=2.57, p&lt;0.001), chronic kidney disease (OR=4.48, p&lt;0.001), history of myocardial infarction (OR=5.09, p&lt;0.001), coronary revascularization (OR=4.31, p&lt;0.001) or cerebrovascular accident (OR=3.07, p&lt;0.001). In ROC-analysis, age ≥65.5 years (OR=3.43, p&lt;0.001), waist-to-hip ratio ≥0.967 (OR=3.01, p=0.001), diabetes duration ≥12.5 years (OR=3.7, p&lt;0.001), duration of insulin therapy ≥4.5 years (OR=3.05, p&lt;0.001), duration of arterial hypertension ≥16.5 years (OR=1.98, p=0.002), serum L-citrulline ≥68 µmol/l (OR=3.82, p=0.003), and mean amplitude of glucose excursions ≥3.72 mmol/l (OR=1.79, p=0.006) were the risk factors for atherosclerosis of two vascular beds. In multivariate logistic regression analysis, age, diabetes duration and waist-to-hip ratio were independent risk factors for association of CA and PAD (p=0.005, p=0.0003, and p=0.004 respectively).CONCLUSION: In subjects with type 2 diabetes, carotid and lower extremity atherosclerotic disease is associated with age, diabetes duration, abdominal obesity, microvascular and macrovascular complications, glucose variability, and high serum levels of L-citrulline

Polymorphism of vascular endothelial growth factor gene (<i>VEGF</i>) and matrix metalloproteinase (<i>ММР</i>) genes in primary limb lymphedema

Among the reasons of primary lymphedema development, a certain role belongs to genetic factors. The specific molecular products participate in remodeling of blood and lymphatic vascular networks. Vascular endothelial growth factors (VEGFs) are key regulators of endothelial functions of the cells, which are responsible for lympho- and vasculogenesis. Moreover, matrix metalloproteinases (ММР) may act as regulators of both lymphangiogenesis, and angiogenesis. Since the regulatory regions of VEGFA gene, as well as of ММР genes are polymorphic, one may suggest, that their different expression level, determined by these polymorphisms, could be associated with development of swellings typical for lymphedema.We have analyzed gene polymorphisms in two regulatory regions of vascular endothelial growth factor-A VEGF-A (rs 699947 and rs 3025039), and matrix metalloproteinase genes MMP2 (rs 2438650), MMP3 (rs 3025058), MMP9 (rs 3918242), and their combinations in the patients with primary lymphedema.A group of patients with primary lymphedema included 72 subjects (55 women and 17 men) at the age of 18 to 81 years. Control group included 526 inhabitants of Novosibirsk (153 men, 373 women) without chronic diseases, comparable for age with lymphedema patients. We have performed typing of regulatory regions in VEGF (rs 699947, rs 3025039), ММР2 (rs 2438650), ММР3 (rs 3025058), ММР9 genes (rs 3918242). Fifteen complex genotypes have been revealed that were positively associated with disease. Analysis of the gene network topology has outlined the main intergenic interactions upon primary lymphedema development. MMP2 -1306 CC, MMP9 -1562CC and VEGF +936CC arrange the basic knots in the gene network (53% of total interactions). A number of significantly different complex genotypes was revealed at patients with primary lymphedema with normal body mass index (BMI &lt; 25) and obesity (BMI &lt; 30). Hence, frequency of complex genotype VEGF +936 CC: MMP3 -1171 5А6А:MMP9 -1562 CC in the patients with obesity is increased more 5.5-fold compared to the patients with normal BMI.The data obtained may presume a certain value of the analyzed gene polymorphisms in pathogenesis of primary lymphedema. Topological analysis of gene networks allows to study the structural and functional organization of gene-gene interactions for development of approaches to individyal preventive maintenance and therapy of the disease

Expansion of a superconducting vortex core into a diffusive metal

© 2018 The Author(s). Vortices in quantum condensates exist owing to a macroscopic phase coherence. Here we show, both experimentally and theoretically, that a quantum vortex with a well-defined core can exist in a rather thick normal metal, proximized with a superconductor. Using scanning tunneling spectroscopy we reveal a proximity vortex lattice at the surface of 50 nm - thick Cu-layer deposited on Nb. We demonstrate that these vortices have regular round cores in the centers of which the proximity minigap vanishes. The cores are found to be significantly larger than the Abrikosov vortex cores in Nb, which is related to the effective coherence length in the proximity region. We develop a theoretical approach that provides a fully self-consistent picture of the evolution of the vortex with the distance from Cu/Nb interface, the interface impedance, applied magnetic field, and temperature. Our work opens a way for the accurate tuning of the superconducting properties of quantum hybrids

Principles of Standardization of Crimean Hemorrhagic Fever Diagnostics and Its Present-Day Peculiarities in the Territory of the Russian Federation

It is stated that due to epidemic manifestations Crimean hemorrhagic fever (CHF) has recently become one of the most pressing issues in the South of the European part of the Russian Federation, the area where its integrated natural focus is situated. In this respect, analyzed are the data on CHF monitoring over the past decade (since 1999); determined are the main epidemiological peculiarities of the infection in the modern period. Furthermore, outlined are the basic principles of development of the unified standard concerning epidemiological and laboratory diagnostics of the disease. Emphasized is the importance of differentiation in scope and nomenclature of diagnostic investigations in laboratory facilities of different echelons, which makes it possible to increase plausibility and quality of the surveys conducted, and carry out verification of the results obtained

К вопросу о времени прекращения эмиссии херсоно-византийских монет с монограммами имени «Василий» и титула «деспот» / To a question of time of the termination of issue of the Cherson-Byzantine coins with monograms of “Basil” name and “despot” title in Cherson

В статье рассмотрен вопрос о продолжительности эмиссии в Херсоне бронзовых византийских монет с монограммами слов «Василий» и «деспот», традиционно относимых к начальному периоду правления императора Василия II. На основе статистического анализа закрытых монетных комплексов рубежа X—XI веков из раскопок Херсона, в которых монеты вышеуказанного типа составляют 25% от их численного состава, сделан вывод, что данный монетный тип выпускался вплоть до первого десятилетия XI в., а не до 988 или 989 года, как считалось ранее. The article deals with the question of the duration of emission in Cherson bronze Byzantine coins with monograms words “Basil” and “despot” traditionally attributed to the initial period of the reign of Emperor Basil II. Based on the statistical analysis of closed coin complexes abroad X—XI centuries of excavation of Cherson, in which the above-mentioned coin-type account for 25% of the number of members, it was concluded that the coin type issued until the first decade of the XI c., but not before 988 or 989 year, as previously thought