About the aftershocks, the Omori law, and the Utsu formula

After the main shock of an earthquake, a stream of aftershocks that does not subside for a long time is usually observed. Fusakichi Omori found that the frequency of aftershocks decreases hyperbolically with time. It has recently been observed that Omori's law can be viewed as a solution to a differential equation describing the evolution of aftershocks. An alternative way of describing is based on Utsu law, which states that the frequency of aftershocks decreases with time according to a power law. The presented paper is polemical. We discuss the issue of the applicability of each of the three alternative ways of describing aftershocks. The Omori law has a limited scope. The law is valid only in the so-called Omori epoch, after which the earthquake source undergoes a bifurcation. In the Omori epoch, the Utsu law is also valid, but it does not differ in this epoch from the Omori law. The general conclusion is that the existence of the Omori epoch and the phenomenon of bifurcation exclude the possibility of describing by a continuous smooth function. At the same time, the differential evolution equation is applicable both before and after the bifurcation point. Key words: earthquake, main shock, evolution equation, deactivation factor, Omori epoch, bifurcation.Comment: 7 pages, 1 figur

Influence of the composition, structure, and physical and chemical properties of aluminium-oxide-based sorbents on water adsorption ability

Interaction between the water adsorption ability of aluminium-oxide-based sorbents and their chemical composition, acid-base properties of the surface, and textural characteristics has been analysed. Alumina desiccants were synthesized with the centrifugal-thermal activation of gibbsite followed by the hydration of the gibbsite under mild conditions. It was demonstrated that the multicyclic adsorption regeneration of samples under realistic conditions results in structural transformations and changes in the acidity of their surfaces and water adsorption ability. The modification of pseudoboehmite with alkali ions increases surface basicity and the dynamic capacity of adsorbents relating to water vapours. Equations have been presented that describe the adsorption and desorption processes taking place during water vapour adsorption with the materials studied

Peculiarities of the mammographic density of the synchronic bilateral breast cancer

In this article it was made an analysis of the case history out-patient medical records of 30 patients with synchronic bilateral breast cancer (SBBC), 34 patients with unilateral breast cancer (BC) and 32 healthy patients. The obtained results show the higher mammographic density in patients having the synchronic BBC in comparison with the healthy patients and lesser density compared with the unilateral BC. The 2nd grade of the mammographic density is 60% in the group of the synchronic BBC and is higher on 34-35% than that of the two other groups. The presence of the 2nd grade of the mammographic density of the mammary gland requests the more thorough examination (Ultrasonic examination, MRT) for excluding the synchronic BBC

Retraction notice on the article by A.S. Zotov et al. ‘Short-Term Results of Two Strategies in Thoracoscopic Ablation for Lone Atrial Fibrillation’ doi: 10.17816/clinpract110719

Editorial board of the journal informs authors about the retraction of the article Short-Term Results of Two Strategies in Thoracoscopic Ablation for Lone Atrial Fibrillation published in Journal of Clinical Practice 13(3) 2022 by A.S. Zotov, O.Yu. Pidanov, I.S. Osmanov, A.V. Troitsky, A.A. Silaev, E.R. Sakharov, V.N. Sukhotin, O.O. Shelest, R.I. Khabazov, D.A. Timashkov. The reason for the retraction is the publication ethics violation in terms of authorship criteria. Not all authors whose names appear on the article made substantial contributions to the study drafted/revised the manuscript and approved the version to be published. Retraction made on January 09, 2023 with approve from the Editor-in-Chief

Cardiopulmonary Test As A Component in the Diagnostic Algorithm for Heart Failure with Preserved Left Ventricular Ejection Fraction in Patients with Atrial Fibrillation

Background: Patients with heart failure with preserved ejection fraction account for more than half of all hospitalizations because of heart failure. On the other hand, atrial fibrillation and heart failure are quite often diagnosed together and one disease influences the development of the other. Timely and accurate diagnosis of heart failure with preserved ejection fraction is the basis for effective treatment of this category of patients. In 2019, the HFA-PEFF algorithm of diagnosis heart failure with preserved ejection fraction (including patients with atrial fibrillation) was proposed. However, the algorithm implies cardiac catheterization in patients at intermediate risk, which involves certain difficulties and cannot be used in routine practice. As an alternative to cardiac catheterization in the diagnosis of heart failure with preserved ejection fraction, we proposed a noninvasive diagnostic method cardiopulmonary test. However, the value of cardiopulmonary test technique has not been conclusively studied, especially in patients with a combination of chronic heart failure and atrial fibrillation. Aim: The aim of the study was to evaluate the role of the cardiopulmonary test in the diagnosis of heart failure with preserved ejection fraction in patients with atrial fibrillation. Methods: 138 patients with atrial fibrillation were included in our study. Using HFA-PEFF algorithm (algorithm for diagnosis of heart failure with preserved left ventricular ejection fraction) all patients were initially divided into 3 groups: low probability of heart failure 23 patients, intermediate probability 96 and high probability 19 patients. The stress-test allowed to precisely assess of patients at intermediate risk and finally form the groups: Group 1 without heart failure, 85 patients (61.6%); Group 2 patients with heart failure and preserved ejection fraction, 53 patients (38.4%). The next diagnostic stage was cardiopulmonary test. Results: During cardiopulmonary test, the anaerobic exercise threshold was 6.8 and 4.85 METs for the first and second groups, respectively (p 0.001), reflecting lower exercise tolerance in the second group of patients. Analysis of variance (ANOVA) demonstrated a statistically significant increase in pro-BNP levels with a decrease in peak VO2 (p 0.001). Also, analysis of variance demonstrated a significant statistical difference with respect to systolic pulmonary artery pressure in the subgroups with severely, moderately reduced oxygen consumption and in the group with normal peak VO2 (p=0.01). ROC analysis determined a peak VO2 of 20 ml/kg/min, above which the HFA-PEFF algorithm was unlikely to detect heart failure (AUC 0.73; confidence interval 0.650.82; p=0.043; sensitivity 85%; specificity 51%). Conclusion: The cardiopulmonary test is a reliable instrumental non-invasive method in the diagnosis of heart failure with preserved ejection fraction

Synthesis of two-dimensional TlxBi1-x compounds and Archimedean encoding of their atomic structure

Crystalline atomic layers on solid surfaces are composed of a single building block, unit cell, that is copied and stacked together to form the entire two-dimensional crystal structure. However, it appears that this is not an unique possibility. We report here on synthesis and characterization of the one-atomic-layer-thick TlxBi1−x compounds which display quite a different arrangement. It represents a quasi-periodic tiling structures that are built by a set of tiling elements as building blocks. Though the layer is lacking strict periodicity, it shows up as an ideally-packed tiling of basic elements without any skips or halting. The two-dimensional TlxBi1−x compounds were formed by depositing Bi onto the Tl-covered Si(111) surface where Bi atoms substitute appropriate amount of Tl atoms. Atomic structure of each tiling element as well as arrangement of TlxBi1−x compounds were established in a detail. Electronic properties and spin texture of the selected compounds having periodic structures were characterized. The shown example demonstrates possibility for the formation of the exotic low-dimensional materials via unusual growth mechanisms

The first experience of a hybrid approach in the surgical treatment of atrial fibrillation

Background: Atrial fibrillation (AF) is the most common arrhythmia in clinical practice and is associated with an increased risk of death, progression of heart failure, and the development of cardiogenic thromboemboli. Despite the significant success in the management of AF in the paroxysmal form, the results of the treatment for patients with persistent forms of AF remain unsatisfactory. Though the surgical approach provides higher rates of efficiency regarding the restoration of a sinus rhythm, transmural lesions are not always attainable, as a result, the rate of AF recurrence in the long-term period remains fairly high. It is also impossible to create ablative patterns to the mitral and tricuspid valves during thoracoscopic epicardial ablation, which can cause the development of recurrent AF, perimitral and typical atrial flutter. Therefore, the development of hybrid approaches combining the advantages of catheter and thoracoscopic techniques is an urgent task of contemporary surgical and interventional arrhythmology. Aims: to estimate the immediate results of a hybrid approach in the management of patients with persistent AF. Methods: We report the first experience of a hybrid treatment of patients with persistent AF. 6 patients aged 53-64 years (1 female, 5 males) were included in the study. At the first stage, thoracoscopic epicardial bipolar ablation was performed (modified GALAXY protocol); the second stage (in 3 to 6 months after the thoracoscopic stage) included an intracardiac electrophysiological study with three-dimensional endocardial mapping followed by endocardial ablation. Results: The thoracoscopic stage of the hybrid treatment included ablation according to the box lesion scheme using a bipolar irrigation equipment. No lethal outcomes and severe, life-threatening complications were registered. The duration of the inpatient period was 510 hospital-days. The 2nd stage of the hybrid treatment was limited to intracardiac electrophysiological examination only in 2 patients. In 4 patients, epicardial radiofrequency ablation was complemented by endocardial radiofrequency exposure. In 3 of the 4 patients who underwent endocardial radiofrequency ablation, catheter ablation of the mitral and cavotricuspid isthmus was required because of the induction of perimitral and typical flutter, respectively. After the 2nd stage of the hybrid treatment, at the time of discharge all the patients maintained a stable sinus rhythm. There were no severe complications or lethal outcomes. Conclusion: a hybrid approach in the AF management is a safe and effective method of treatment, which combines the advantages of minimally invasive surgery and endocardial intervention in patients with persistent AF. The technique is safe and has acceptable short-term results

Improving the accuracy of machining of non-rigid shaft

So far, due to much more strict events of operating parameters requirements, the reduction of pieces steel intensity allows to produce multiplying quantity of the highly precise Non-Rigid Pieces (NRP); most of them are supposed to be the shafts in amount. The creation of Automatic Control Systems (ACS) by mechanical operating also involves highly precise NRP production. In present paper there is Self-Centering Rest (SCR) operating hydrocylinder piston rod control system presented; it causes influence directly to the rest centering accuracy. The plant processing does not require hydrostation and pipeline; it possesses highly precise centering and it is able to function either in shaft support mode, or in active dampening one. There is the original scheme of double acting sealed hydrocylinder presented. There is the functional control scheme of hydraulic power cylinder presented. There are results of the non-rigid shaft axle research while turning presented. Thus, the beat reduction of the rigid shaft while turning in SCR system reaches 3...16 times in comparison