Method to determine defect positions below a metal surface by STM

The oscillatory voltage dependence of the conductance of a quantum point contact in the presence of a single point-like defect has been analyzed theoretically. Such signals are detectable and may be exploited to obtain information on defect positions below a metal surface. Both tunnel junctions and ballistic contacts of adiabatic shape have been considered. The effect of quantum interference has been taking into account between the principal wave that is directly transmitted through the contact and the partial wave that is scattered by the contact and the defect. This effect leads to oscillations of the conductance as a function of applied voltage. We obtain the dependence of the period and amplitude of the conductance oscillations on the position of the defect inside the metal.Comment: 16 pages, 7 figure

Temperature-dependent quantum electron transport in 2D point contact

We consider a transmission of electrons through a two-dimensional ballistic point contact in the low-conductance regime below the 0.7-anomaly. The scattering of electrons by Friedel oscillations of charge density results in a contribution to the conductance proportional to the temperature. The sign of this linear term depends on the range of the electron-electron interaction and appears to be negative for the relevant experimental parameters.Comment: 10 pages, 5 figure

Secreted hydrolases from streptomycin-resistant strains of Bacillus intermedius

Alkaline phosphatase and serine proteinase have been isolated from streptomycin-resistant strains of Bacillus intermedius using ion-exchange, affinity and FPLC chromatography. Substrate blotting analysis and electrophoresis revealed two phosphatase forms with molecular weight of 40 and 50 kDa. The pH and temperature optima of phosphatase were at pH 9.5 and 50°C. The enzyme showed a broad substrate specificity. It was suggested that the two forms of phosphatase are the products of processing, in which serine proteinase is the participant. Two proteinase peaks with molecular weights of 29 and 33 kDa were isolated from B. intermedius S7, the first peak having only 5% of the activity of the second peak. The major peak was identical to serine proteinase described earlier. The minor peak was distinct from the major one by the pH-optima. Analysis of inhibitors' effects revealed that the minor peak also corresponded to serine proteinase

К 100-ЛЕТНЕМУ ЮБИЛЕЮ ПЕРВОЙ В МИРЕ КАФЕДРЫ РЕНТГЕНОЛОГИИ

The article reflects the stages of development of the first in the world department of radiology throughout the century. During the existence of the department, it was headed by eminent scientists. Under their leadership, the department staff made an invaluable contribution not only to the development of radiology as a science, but also to the development of teaching this specialty in the USSR. The traditions of innovation and teaching excellence laid down by the founders of the department are preserved and developed at the present stage.В статье отражены этапы развития первой в мире кафедры рентгенологии на протяжении века. За время существования кафедры ею руководили выдающиеся ученые. Под их руководством сотрудники кафедры внесли неоценимый вклад не только в развитие рентгенологии как науки, но и в становление преподавания этой специальности в СССР. Традиции новаторства и мастерства преподавания, заложенные основоположниками кафедры, сохраняются и развиваются на современном этапе

Secreted hydrolases from streptomycin-resistant strains of Bacillus intermedius

Alkaline phosphatases and serine proteinases have been isolated from the culture liquid of streptomycin-resistant strains of Bacillus intermedius using ion-exchange and affinity chromatography and FPLC. Substrate blotting and electrophoresis revealed two phosphatase forms with molecular masses of 40 and 50 kD. The enzyme had maximal activity at pH 9.5 and 50°C and could cleave the phosphate moiety from a range of substrates. It is suggested that both forms of the phosphatase are products of processing that involves a serine proteinase. Two proteinases, with molecular masses of 29 and 33 kD, were purified to homogeneity from the culture liquid of A. intermedius S7. The protein from the major peak was identical in its properties to an earlier described serine proteinase. The minor peak was 5% of the major one. These enzymes had different pH optima. Inhibitor analysis indicated that the minor peak is also a serine proteinase

Enzymatic properties of thiol-dependent serine proteinase of Bacillus intermedius 3-19

Effects of a thiol-dependent serine proteinase of Bacillus intermedius on peptide substrates and insulin B-chain were studied. The enzyme preferably splits peptide bonds formed by carboxyl groups of hydrophobic amino acids. Ca2+ increases the thermal stability of the proteinase significantly. The kinetic characteristics of hydrolysis of Z-Ala-Ala-Leu-pNA by this enzyme was determined as Km = 1.25 mM and kcat = 0.15 sec-1. The enzyme has high stability to DMFA and isopropanol, and is able to catalyze peptide bond synthesis

Andreev reflection and order parameter symmetry in heavy-fermion superconductors: the case of CeCoIn5_5

We review the current status of Andreev reflection spectroscopy on the heavy fermions, mostly focusing on the case of CeCoIn$_5$, a heavy-fermion superconductor with a critical temperature of 2.3 K. This is a well-established technique to investigate superconducting order parameters via measurements of the differential conductance from nanoscale metallic junctions. Andreev reflection is clearly observed in CeCoIn$_5$ as in other heavy-fermion superconductors. The measured Andreev signal is highly reduced to the order of maximum $\sim$ 13% compared to the theoretically predicted value (100%). Analysis of the conductance spectra using the extended BTK model provides a qualitative measure for the superconducting order parameter symmetry, which is determined to be $d_{x^2-y^2}$-wave in CeCoIn$_5$. A phenomenological model is proposed employing a Fano interference effect between two conductance channels in order to explain both the conductance asymmetry and the reduced Andreev signal. This model appears plausible not only because it provides good fits to the data but also because it is highly likely that the electrical conduction occurs via two channels, one into the heavy electron liquid and the other into the conduction electron continuum. Further experimental and theoretical investigations will shed new light on the mechanism of how the coherent heavy-electron liquid emerges out of the Kondo lattice, a prototypical strongly correlated electron system. Unresolved issues and future directions are also discussed.Comment: Topical Review published in JPCM (see below), 28 pages, 9 figure

Global mortality and readmission rates following COPD exacerbation-related hospitalisation: a meta-analysis of 65 945 individual patients

\ua9 2024, European Respiratory Society. All rights reserved.Background Exacerbations of COPD (ECOPD) have a major impact on patients and healthcare systems across the world. Precise estimates of the global burden of ECOPD on mortality and hospital readmission are needed to inform policy makers and aid preventive strategies to mitigate this burden. The aims of the present study were to explore global in-hospital mortality, post-discharge mortality and hospital readmission rates after ECOPD-related hospitalisation using an individual patient data meta-analysis (IPDMA) design. Methods A systematic review was performed identifying studies that reported in-hospital mortality, postdischarge mortality and hospital readmission rates following ECOPD-related hospitalisation. Data analyses were conducted using a one-stage random-effects meta-analysis model. This study was conducted and reported in accordance with the PRISMA-IPD statement. Results Data of 65 945 individual patients with COPD were analysed. The pooled in-hospital mortality rate was 6.2%, pooled 30-, 90- and 365-day post-discharge mortality rates were 1.8%, 5.5% and 10.9%, respectively, and pooled 30-, 90- and 365-day hospital readmission rates were 7.1%, 12.6% and 32.1%, respectively, with noticeable variability between studies and countries. Strongest predictors of mortality and hospital readmission included noninvasive mechanical ventilation and a history of two or more ECOPD-related hospitalisation

Analysis of the restoration of cardiology diagnostics scope in the Russian Federation during the COVID-19 pandemic: results of the Russian segment of the INCAPS COVID 2 study under the auspices of the International Atomic Energy Agency

Aim. To assess the changes in cardiology diagnostics scope in the Russian Federation during the coronavirus disease 2019 (COVID-19) pandemic.Material and methods. In an online survey organized by the Division of Human Health of the International Atomic Energy Agency (IAEA), including questions about changes in the workflow of diagnostic laboratories and the scope of cardiac diagnostics from March 2019 (pre-pandemic) to April 2020 (first wave of the pandemic) and April 2021 (recovery stage), 15 Russian medical centers from 5 cities took part.Results. The decrease in the diagnostics scope by April 2020 by 59,3% compared to March 2019, by April 2021, stopped and was replaced by growth (+7,1%, the recovery rate, 112,1%). The greatest increase was in routine examinations, such as echocardiography (+11,6%), stress echocardiography (+18,7%), stress single photon emission computed tomography (+9,7%), and to a lesser extent resting computed tomography angiography (+7,0%) and magnetic resonance imaging (+6,6%). The performance of stress electrocardiography, stress magnetic resonance imaging and positron emission tomography for the diagnosis of endocarditis in April 2021 compared to March 2019 decreased by 10,3%, 63,2% and 62,5%, respectively.Conclusion. Due to the resumption of patient admissions for cardiac examinations during the ongoing COVID-19 pandemic, with the anti-epidemic measures taken and certain changes in the workflow, there has been a recovery in the diagnostics scope in most of the included centers