Electron-conformational transformations in nanoscopic RyR channels govern both the heart's contraction and beating

We show that a simple biophysically based electron-conformational model of RyR channel is able to explain and describe on equal footing the oscillatory regime of the heart's cell release unit both in sinoatrial node (pacemaker) cells under normal physiological conditions and in ventricular myocytes under Ca$^{2+}$ SR overload.Comment: 6 pages, 3 figure

Social Distancing and the Deficit of Presence (Philosophical Reflection of the Covid-19 Pandemic)

The paper claims that if the COVID-19 pandemic turned out to be a man-made risk (А. Giddens), i.e. an unforeseen consequence of a person’s own behavior and actions, then in order to avoid such fatal contingences that occur so unexpectedly, it is necessary to change the type of behavior and actions that have established in the culture of the Modern Period. During the pandemic people are forced to observe the spatial order. Distancing, self-isolation, the Red Zone and other spatial limitations made people acutely aware of the deficit of presence, the lack of their independent active participation in life. The new virus, on the one hand, returned a person to the awareness of the biological, natural origin of human existence, which has been forgotten by culture (science). On the other hand, the practices of social rationing and restriction revealed the influence of various forms of alienation — social, political, economic, cultural — on the fate of each individual. The introduction of the bioprinciple (the virus) into the social, cultural and political space radically changes the relationship between people and nature. This situation makes one think about the meaning of the notion of culture, which got its definition in the 18th century and is understood as non-nature reflected in the formula culture vs nature. The paper shows that the cultural ideal of human activity, which was established in modern times, became the reason of the alienation of technogenic civilization and social forms of life from nature. By destroying nature, turning it into the material for people’s various techne, people found themselves in conflict with their own life. Culture has lost its inner meaning of the presence of the world and of an individual which dissolved in various interpretations and ideas. Contemporary history is moving towards the establishment of a culture of Presence, where the world is viewed not as a mere material to be used, but an area for humans to engage with. What we see today is the assertion of the right to difference and the right to the presence of diversity — in nature, culture, politics (struggle for a multipolar world), in the personal domain (selfies, blogs, chats, etc.)

Role of myocardial properties and pacing lead location on ECG in personalized paced heart models

Personalised cardiac models were built from the computed tomography imaging data for two patients with implanted cardiac resynchronisation therapy devices. The cardiac models comprised a biventricular model of myocardial electrophysiology coupled with a model of the torso to simulate the body surface potential map. The models were verified against electrocardiogams (ECG) recorded in the patients from 240 leads on the body surface under left ventricular pacing. The simulated ECG demonstrated a significant sensitivity to the myocardial anisotropy and location of the pacing electrode tip in the models. An apicobasal cellular heterogeneity was shown to be less significant for the ECG pattern at the paced-ventricle activation than that showed earlier by Keller and co-authors (2012) for the normal activation sequence. © 2017 IEEE Computer Society. All rights reserved.This study was supported by the RAS Presidium Programme I.33Π, and Government of the Russian Federation (agreement 02.A03.21.0006). We used the computational clusters of Ural Federal University and ”URAN” of Institute of Mathematics and Mechanics (Ekaterinburg)

Drift of scrollwaves in a mathematical model of a heterogeneous human heart left ventricle

Rotating spiral waves of electrical excitation underlie many dangerous cardiac arrhythmias. The heterogeneity of myocardium is one of the factors that affects the dynamics of such waves. In this paper, we present results of our simulations for scroll wave dynamics in a heterogeneous model of the human left ventricle with analytical anatomically based representation of the geometry and anisotropy. We used a set of 18 coupled differential equations developed by ten Tusscher and Panfilov (TP06 model) which describes human ventricular cells based on their measured biophysical properties. We found that apicobasal heterogeneity dramatically changes the scroll wave dynamics. In the homogeneous model, the scroll wave annihilates at the base, but the moderate heterogeneity causes the wave to move to the apex and then continuously rotates around it. The rotation speed increased with the degree of the heterogeneity. However, for large heterogeneity, we observed formation of additional wavebreaks and the onset of complex spatio-temporal patterns. Transmural heterogeneity did not change the dynamics and decreased the lifetime of the scroll wave with an increase in heterogeneity. Results of our numerical experiments show that the apex may be a preferable location of the scroll wave, which may be important for development of clinical interventions. © 2020 by the authors.AAAA-A18-118020590031-8Russian Foundation for Basic Research, RFBR: 18-29-13008Russian Science Foundation, RSF: 14-35-00005Ural Federal University, UrFUP.K., S.P., O.S., and A.V.P. were funded by the Russian Science Foundation (project 14-35-00005). A.V.P., P.K., and O.S. were funded by the Russian Foundation for Basic Research (#18-29-13008). A.V.P. and O.S. were funded by RF Government Act #211 of 16 March 2013 (agreement 02. A03.21.0006). P.K. and O.S. work was carried out within the framework of the IIF UrB RAS theme No. AAAA-A18-118020590031-8. A.V.P. and H.D. were partially funded by BOF Ghent University. Simulations were performed at the supercomputer Uran of Institute of Mathematics and Mechanics (Ekaterinburg, Russia) and at the supercomputer of Ural Federal University (Ekaterinburg, Russia)

Anemia in Women of Reproductive Age

Anemia is a common condition in women of childbearing age which is associated with wide spread hyperplastic processes in the uterus (leiomyomas, etc.) and abnormal and/or abundant uterine bleeding (AUB). Our study has considered the main causes of bleeding and the therapy aimed on limiting the amount of blood loss, as well as preoperative treatment of iron deficiency in women with uterine leiomyomas, planning for pregnancy. The combination of anemia with other abnormalities in the woman’s health status is associated with complications during pregnancy such as premature births, the birth of small children and failure of the formation of neural tube in iron deficiency and hypoxia. During the treatment of iron deficiency anemia (IDA) with saline iron, we noted severity and pain in the stomach in 11.9% of patients, nausea in 13.1%, constipation in 21.4%, and diarrhea in 7.1% of women. Such complications did not occur while treating with ferric iron. The use of drugs Iron III hydroxide polymaltozate in women after the end of lactation resulted in normalization of the blood hemoglobin within 30 days and the number of erythrocytes and of serum ferritin by the 90th day

Model order reduction for left ventricular mechanics via congruency training

Computational models of the cardiovascular system and specifically heart function are currently being investigated as analytic tools to assist medical practice and clinical trials. To achieve clinical utility, models should be able to assimilate the diagnostic multi-modality data available for each patient and generate consistent representations of the underlying cardiovascular physiology. While finite element models of the heart can naturally account for patient-specific anatomies reconstructed from medical images, optimizing the many other parameters driving simulated cardiac functions is challenging due to computational complexity. With the goal of streamlining parameter adaptation, in this paper we present a novel, multifidelity strategy for model order reduction of 3-D finite element models of ventricular mechanics. Our approach is centered around well established findings on the similarity between contraction of an isolated muscle and the whole ventricle. Specifically, we demonstrate that simple linear transformations between sarcomere strain (tension) and ventricular volume (pressure) are sufficient to reproduce global pressure-volume outputs of 3-D finite element models even by a reduced model with just a single myocyte unit. We further develop a procedure for congruency training of a surrogate low-order model from multiscale finite elements, and we construct an example of parameter optimization based on medical images. We discuss how the presented approach might be employed to process large datasets of medical images as well as databases of echocardiographic reports, paving the way towards application of heart mechanics models in the clinical practice. © 2020 Di Achille et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.19-14- 00134Russell Sage Foundation, RSFSK and OS were funded by RSF (http:// www.rscf.ru/en/) as described below. Part of this work was carried out within the framework of the IIF UrB RAS government assignment and was partially supported by the UrFU Competitiveness Enhancement Program (agreement 02. A03.21.0006) as well as the RSF grant (No. 19-14- 00134). The Uran supercomputer at IMM UrB RAS was used for part of the model calculations. IBM provided support in the form of salaries for authors PA, JP, JK and VG but did not have any additional role in the study design, data collection and analysis, decision to publish, or preparation of the manuscript. The specific roles of these authors are articulated in the "author contributions" section

Application of Microsecond Voltage Pulses for Water Disinfection by Diaphragm Electric Discharge

The paper presents the dependence of copper and silver ions formation on the duration of voltage pulses of diaphragm electric discharge and on the pH of treated liquid medium. Knowing it allows one to create an automatic control system to control bactericidal agent's parameters obtained in diaphragm electric discharge reactor. The current-voltage characteristic of the reactor with a horizontal to the diaphragm membrane water flow powered from the author`s custom pulse voltage source is also presented. The results of studies of the power consumption of diaphragm electric discharge depending on temperature of the treated liquid medium are given

Study of Antibiotic Resistance of the Oropharyngeal Hemolytic Microflora in Preschool Children

It is impossible to imagine modern medical practice without antibiotic therapy. However, the rapid development of the pharmaceutical industry expands free access of the population to antibacterial drugs. At the same time, the illiteracy of people with respect to the principles of rational antibiotic therapy also increases. The problem of microbial resistance to antibacterial drugs remains relevant to this day. Special attention should be paid to rational antibiotic therapy applied to children.The purpose of this work was to study the resistance of hemolytic microorganisms, which are often the cause of upper respiratory infection in preschool children, to the main antibacterial drugs used in pediatric practice. The results of this scientific research can be advisory and useful to pediatricians and other specialists whose professional activities are related to children’s health. Keywords: hemolytic active microorganisms, bacterial carriage, antibiotic resistance, children’s healt

Parameter variations in personalized electrophysiological models of human heart ventricles

The objectives of this study were to evaluate the accuracy of personalized numerical simulations of the electrical activity in human ventricles by comparing simulated electrocardiograms (ECGs) with real patients' ECGs and analyzing the sensitivity of the model output to variations in the model parameters. We used standard 12-lead ECGs and up to 224 unipolar body-surface ECGs to record three patients with cardiac resynchronization therapy devices and three patients with focal ventricular tachycardia. Patient-tailored geometrical models of the ventricles, atria, large vessels, liver, and spine were created using computed tomography data. Ten cases of focal ventricular activation were simulated using the bidomain model and the TNNP 2006 cellular model. The population-based values of electrical conductivities and other model parameters were used for accuracy analysis, and their variations were used for sensitivity analysis. The mean correlation coefficient between the simulated and real ECGs varied significantly (from r = 0.29 to r = 0.86) among the simulated cases. A strong mean correlation (r > 0.7) was found in eight of the ten model cases. The accuracy of the ECG simulation varied widely in the same patient depending on the localization of the excitation origin. The sensitivity analysis revealed that variations in the anisotropy ratio, blood conductivity, and cellular apicobasal heterogeneity had the strongest influence on transmembrane potential, while variation in lung conductivity had the greatest influence on body-surface ECGs. Futhermore, the anisotropy ratio predominantly affected the latest activation time and repolarization time dispersion, while the cellular apicobasal heterogeneity mainly affected the dispersion of action potential duration, and variation in lung conductivity mainly led to changes in the amplitudes of ECGs and cardiac electrograms. We also found that the effects of certain parameter variations had specific regional patterns on the cardiac and body surfaces. These observations are useful for further developing personalized cardiac models