Development of a method for calibrating a potentiometer

The article discusses the nomenclature and metrological characteristics of the potentiometer. Description of the structure and content of the calibration method for one of the largest enterprises in Ekaterinburg.В статье рассматривается номенклатура и метрологические характеристики потенциометра. Описание структуры и содержания методики его калибровки для одного из крупных предприятий Екатеринбурга

Pressure effect on magnetic susceptibility of LaCoO3_3

The effect of pressure on magnetic properties of LaCoO$_3$ is studied experimentally and theoretically. The pressure dependence of magnetic susceptibility $\chi$ of LaCoO$_3$ is obtained by precise measurements of $\chi$ as a function of the hydrostatic pressure $P$ up to 2 kbar in the temperature range from 78 K to 300 K. A pronounced magnitude of the pressure effect is found to be negative in sign and strongly temperature dependent. The obtained experimental data are analysed by using a two-level model and DFT+U calculations of the electronic structure of LaCoO$_3$. In particular, the fixed spin moment method was employed to obtain a volume dependence of the total energy difference $\Delta$ between the low spin and the intermediate spin states of LaCoO$_3$. Analysis of the obtained experimental $\chi(P)$ dependence within the two-level model, as well as our DFT+U calculations, have revealed the anomalous large decrease in the energy difference $\Delta$ with increasing of the unit cell volume. This effect, taking into account a thermal expansion, can be responsible for the temperatures dependence of $\Delta$, predicting its vanishing near room temperature.Comment: 7 pages, 9 figure

Complex experiment on studying the microphysical, chemical, and optical properties of aerosol particles and estimating the contribution of atmospheric aerosol-to-earth radiation budget

The primary objective of this complex aerosol experiment was the measurement of microphysical, chemical, and optical properties of aerosol particles in the surface air layer and free atmosphere. The measurement data were used to retrieve the whole set of aerosol optical parameters, necessary for radiation calculations. Three measurement cycles were performed within the experiment during 2013: in spring, when the aerosol generation is maximal; in summer (July), when atmospheric boundary layer altitude and, hence, mixing layer altitude are maximal; and in late summer/early autumn, during the period of nucleation of secondary particles. Thus, independently obtained data on the optical, meteorological, and microphysical parameters of the atmosphere allow intercalibration and inter-complement of the data and thereby provide for qualitatively new information which explains the physical nature of the processes that form the vertical structure of the aerosol field

Evaluation of the Effect of Comorbidity on the Efficacy and Safety of β-Lactam Antibiotics in Patients with Community-Acquired Pneumonia

Lower respiratory tract infections, which include community-acquired pneumonia (CAP), are the most common cause of death among all infectious diseases. The presence of a comorbid pathology in a patient with CAP suggests a possibility of mutual influence and changes in the course of both the underlying disease and comorbidities, as well as changes in the effectiveness and safety of ongoing drug therapy. The aim of the study was to analyse literature data on the structure of comorbidity in CAP patients and its impact on the efficacy and safety of therapy with β-lactam antibiotics. It has been established that CAP most often occurs in patients with chronic obstructive pulmonary disease, cardiovascular diseases (ischemic heart disease, arterial hypertension, and chronic heart failure), cerebrovascular disease, chronic kidney disease, diabetes mellitus, bronchial asthma, leukemia, anemia, dementia, neurological disorders, and cancer. The most common causative agent of CAP, regardless of the patient’s age and comorbidity, is pneumococcus (Streptococcus pneumoniae), followed by intracellular pathogens (mycoplasmas, chlamydia) and Haemophilus influenzae, as well as respiratory viruses. With this in mind, the initial empiric therapy for CAP mainly includes β-lactam antibiotics, which are effective against pneumococcus. If patients with CAP have concomitant chronic diseases and conditions, the spectrum of pneumonia pathogens may differ from that in the general population and include rare pathogens and multidrug-resistant strains. The effectiveness of antibiotic therapy in such patients is reduced, which leads to a worsening of the course of both CAP and concomitant diseases. This patient population may require longer treatment with antibiotics, including β-lactams, or the use of antibiotics at doses that provide a higher minimum inhibitory concentration, which is associated with a high risk of adverse reactions and a decrease in the safety of antibiotic therapy

Upper limits on the isotropic diffuse flux of cosmic PeV photons from Carpet-2 observations

Isotropic diffuse gamma-ray flux in the PeV energy band is an important tool for multimessenger tests of models of the origin of high-energy astrophysical neutrinos and for new-physics searches. So far, this flux has not yet been observed. Carpet-2 is an air-shower experiment capable of detecting astrophysical gamma rays with energies above 0.1 PeV. Here we report the upper limits on the isotropic gamma-ray flux from Carpet-2 data obtained in 1999-2011 and 2018-2022. These results, obtained with the new statistical method based on the shape of the muon-number distribution, summarize Carpet-2 observations as the upgraded installation, Carpet-3, starts its operation.Comment: 5 pages, 3 figures, JETPL.cls; V2: references added, version accepted by JETP Letter

Retrospective Analysis of the Safety of Antibacterial Medicinal Products for Elderly Patients with Community-Acquired Lower Respiratory Tract Infections

Cephalosporins are the empirical antibiotic therapy (ABT) of choice for patients with community-acquired pneumonia (CAP). When treated with antibiotics, elderly patients, especially those with comorbidities, are at higher risk of developing adverse drug reactions (ADRs).The aim of the study was to analyse data on the safety and efficacy of initial empirical ABT with cephalosporins in elderly patients over 75 years old with CAP admitted to multidisciplinary hospitals in Moscow.Materials and methods. The retrospective study included 305 medical records of patients with CAP admitted to three multidisciplinary hospitals in Moscow in 2017–2019 and prescribed initial mono- and/or combination ABT including a cephalosporin. Initial ABT was considered effective if the body temperature normalised within 48–72 h from the start of treatment. It was considered safe if there were no ADRs during hospital stay.Results. Mostly, patients were prescribed ceftriaxone monotherapy or ceftriaxone and azithromycin combination therapy. These ABT regimens were effective in 69.07% and 78.10% of the cases, respectively. Patients with severe CAP needed their initial ABT adjusted significantly more often than those with non-severe CAP. The initial ABT was changed for a number of reasons, including ineffectiveness, ADRs, abscesses formed as a complication of CAP, sputum culture results enabling causal ABT, secondary hospital-acquired infections, and exacerbated chronic infections. All patients had comorbidities, and the most prevalent were arterial hypertension (83.9%), coronary heart disease (45.6%), chronic heart failure (44.9%), cerebrovascular disease (40.9%), atrial fibrillation (26.9%), diabetes mellitus (21.3%), and chronic obstructive pulmonary disease (19.0%). Initial ABT was significantly more often considered ineffective in patients with chronic heart failure and cerebrovascular disease. The most common causative agent of CAP in the study population was Streptococcus pneumoniae (31.9%). In 16% of patients, the authors identified ADRs associated with the antibiotics used as initial therapy. The most common were diarrhoea, anaemia, leucopenia, and hepatopathy. Ceftriaxone was associated with ADRs in 11% of patients.Conclusions. The study results suggest that initial mono- and/or combination ABT including a cephalosporin is effective and relatively safe; therefore, this treatment option is expedient for elderly patients with CAP. For this population, the safety of ABT may be improved through the wider use of existing markers of ADRs and the identification of new ones

ATPase Subdomain IA Is a Mediator of Interdomain Allostery in Hsp70 Molecular Chaperones

The versatile functions of the heat shock protein 70 (Hsp70) family of molecular chaperones rely on allosteric interactions between their nucleotide-binding and substrate-binding domains, NBD and SBD. Understanding the mechanism of interdomain allostery is essential to rational design of Hsp70 modulators. Yet, despite significant progress in recent years, how the two Hsp70 domains regulate each other's activity remains elusive. Covariance data from experiments and computations emerged in recent years as valuable sources of information towards gaining insights into the molecular events that mediate allostery. In the present study, conservation and covariance properties derived from both sequence and structural dynamics data are integrated with results from Perturbation Response Scanning and in vivo functional assays, so as to establish the dynamical basis of interdomain signal transduction in Hsp70s. Our study highlights the critical roles of SBD residues D481 and T417 in mediating the coupled motions of the two domains, as well as that of G506 in enabling the movements of the α-helical lid with respect to the β-sandwich. It also draws attention to the distinctive role of the NBD subdomains: Subdomain IA acts as a key mediator of signal transduction between the ATP- and substrate-binding sites, this function being achieved by a cascade of interactions predominantly involving conserved residues such as V139, D148, R167 and K155. Subdomain IIA, on the other hand, is distinguished by strong coevolutionary signals (with the SBD) exhibited by a series of residues (D211, E217, L219, T383) implicated in DnaJ recognition. The occurrence of coevolving residues at the DnaJ recognition region parallels the behavior recently observed at the nucleotide-exchange-factor recognition region of subdomain IIB. These findings suggest that Hsp70 tends to adapt to co-chaperone recognition and activity via coevolving residues, whereas interdomain allostery, critical to chaperoning, is robustly enabled by conserved interactions. © 2014 General et al

Magnetic Field Amplification in Galaxy Clusters and its Simulation

We review the present theoretical and numerical understanding of magnetic field amplification in cosmic large-scale structure, on length scales of galaxy clusters and beyond. Structure formation drives compression and turbulence, which amplify tiny magnetic seed fields to the microGauss values that are observed in the intracluster medium. This process is intimately connected to the properties of turbulence and the microphysics of the intra-cluster medium. Additional roles are played by merger induced shocks that sweep through the intra-cluster medium and motions induced by sloshing cool cores. The accurate simulation of magnetic field amplification in clusters still poses a serious challenge for simulations of cosmological structure formation. We review the current literature on cosmological simulations that include magnetic fields and outline theoretical as well as numerical challenges.Comment: 60 pages, 19 Figure

Laboratory evidence of dynamo amplification of magnetic fields in a turbulent plasma

Magnetic fields are ubiquitous in the Universe. The energy density of these fields is typically comparable to the energy density of the fluid motions of the plasma in which they are embedded, making magnetic fields essential players in the dynamics of the luminous matter. The standard theoretical model for the origin of these strong magnetic fields is through the amplification of tiny seed fields via turbulent dynamo to the level consistent with current observations. However, experimental demonstration of the turbulent dynamo mechanism has remained elusive, since it requires plasma conditions that are extremely hard to re-create in terrestrial laboratories. Here we demonstrate, using laser-produced colliding plasma flows, that turbulence is indeed capable of rapidly amplifying seed fields to near equipartition with the turbulent fluid motions. These results support the notion that turbulent dynamo is a viable mechanism responsible for the observed present-day magnetization