Analysis of noisy signal restoration quality with Lanczos filter

The differential component of the feedback is used to enhance dynamics of controlled mechanisms in control systems. However, the use of the differential component increases the noise interference, resulting in the need to use different filtering methods. This paper describes the research of a differentiated signal input in a differential Lanczos filter. The influence of the filter order on the integrated square error of the filtered signal is defined. The impact of signal dispersion and a sampling interval on the integrated square error of the filtered signal is identified. Moreover, the most convenient parameter values for the Lanczos filter are determined. The paper also includes the comparison of the exponential moving average filter and the Lanczos filter with selected values of noise dispersion and a sampling interval. The research shows the possibility to apply the Lanczos filter for processing of the differentiated signals

CRYOBALLOON ABLATION IN RUSSIAN SITES OF INTERVENTIONAL ATRIAL FIBRILLATION MANAGEMENT TREATMENT: RESULTS OF THE FIRST NATIONWIDE SURVEY

Aim. The results of cryoballoon ablation (CBA) are known from the studies performed in the experienced centers of catheter treatment of atrial fibrillation (AF). The current study presents the results of CBA in real practice in centers with various experienceMaterial and methods. Among 62 Russian sites performing catheter treatment of AF, in 15 the CBA methods were in use to isolate pulmonary veins, in the years 2012-2014. Centers staff were surveyed for the detailed description of all performed CBA till 10.2014. The questionnaire included 74 lines about the centers experience, patients properties and ablation procedures, management of patients and complications. At the second step the questionnaire was used about complications.Results. Thirteen centers provided full data on all patients with CBA (457 procedures; 94% for paroxysmal AF; >95% CBAs in Russia). Six centers were marked as highly experienced for CBA for AF (mean 414,2±339,4 ablations for AF per year), and 7 — with lesser experience (33,2±34,3 ablations for AF per year). Ten centers provided the results of 6/12 month observation, and 11 centers — detalization of the complications data. there were no statistically significant differences in arrhythmia absence in patients from both types of centers (61,9±10,0 versus 61,3±30,4%). Serious complications developed in 1,5% of patients (4 tamponades, 2 strokes and 1 diaphragmal nerve palsy) and were similarly spread among more and less experienced centers (1,4% vs. 2%, p>0,05). Minor adverse events (vascular, transient diaphragm nerve palsy, transient hemoptysis) were found in 37 (8%) patients and were more common in more experienced (teaching) centers. Overall frequency of adverse events and of vascular events was higher in females than males (12% and 4,9% vs. 6% and 0%, resp.; p<0,05).Conclusion. In the real clinical practice CBA is performed with acceptable efficacy and moderate frequency of adverse events development. In less experienced centers of catheter treatment of AF the prevalence of serious adverse events does not differ from less experienced. Women develop vascular complications more often

Evaluation of the possibility of wireless data transmission over rocks for automating an alarm system in mines using lowfrequency electromagnetic waves and radio tags

The paper discusses the possibility of organizing a wireless data transmission channel in place of different kinds of mines for signalling and emergency communication using electromagnetic waves in the VLF propagation (300 Hz - 3 kHz). The paper gives theoretical estimates of the efficiency of propagation of electromagnetic waves in rocks and minerals with different values of electrical conductivity. The dependence of the depth of penetration on frequency is also studied. A review of the existing technical solutions to this problem is given. An analytical and numerical analysis of the current density in the rock and the magnetic field created by it using a radiating long cable is given. Reception of a signal with an informational message is carried out with the help of an individual radio tag informing personnel both in conditions of the mine's normal operation and in emergency situations. Comparative evaluations of the efficiency of using radio tags with different configurations of a receiving antenna in mine conditions at a depth of up to 800 m are give

Optimization of two-stage methanogenesis regime based on the Pontryagin’s maximum principle ***

Introduction. The solution to the problem of optimal control of the biogas process under its conversion in two digesters is considered. The work objectives are to propose a mathematical model of this process and to develop an optimal control algorithm.Materials and Methods. The developed mathematical model describes the biomethanation from animal waste through the downstream processing of the substrate in two digesters. Cases of the same and different temperature media (mesophilic and thermophilic) are considered. An optimal control problem is defined as a Lagrange problem for this model. Its modifiers are the rates of substrate entry into the digesters. The algorithm for solving this problem is proposed; it is based on the numerical implementation of the Pontryagin maximum principle. When optimizing, a hybrid genetic algorithm was used with an additional search in the neighborhood of the best solution through the conjugate gradient method.Research Results. A new mathematical model is developed. It describes the biomethanation during the downstream processing of the substrate in two digesters. A numerical algorithm for solving an optimal control problem is proposed and software-implemented. The numerical studies have shown that the biogas production rate is nearly twice as high for a thermophilic medium as for a mesophilic one. It is established that the downstream processing of the substrate in two digesters with the same temperature medium allows the biogas production rate to be doubled. If the temperature media in the digesters are different, then in the first of them, the mesophilic medium should be used, and in the second - the thermophilic medium. At this, the biogas formation rate is somewhat lower compared to the case when there is a mesophilic medium in each of the digesters; however, the degree of the substrate processing is by 10-15% higher.Discussion and Conclusions. The results obtained can be used for the calculation and design of biogas plants, as well as in the development of appropriate software

RESULTS OF PRIMARY AND REVISION REVERSE SHOULDER ARTHROPLASTY

There is a report of two clinical cases of reverse shoulder joint replacement. In the first case, reverse arthroplasty performed in post-traumatic avascular necrosis of the humeral head. In the second case, the arthroplasty with reverse prosthesis was performed because of insufficiency of rotator cuff, and due to this, dislocation of unipolar shoulder. In both cases we achieved good functional outcome

ANALYSIS OF LONG-TERM RESULTS OF SHOULDER ARTHROPLASTY

The retrospective analysis of 97 shoulder arthroplasties during 1998 to 2009 was performed. The hemiarthroplasty were fulfilled in 92 patients and total shoulder replacement in 5 patients. Total rate good and satisfactory results consists 32,0%, poor results - 68,0% (66 patients, include 5 patients with total shoulder arthroplasty). The lower level of good results was revealed in patients with chronic fractures and fracture-dislocations of shoulder. It related with changes bones of shoulder and muscles of shoulder (rotator cuff). In the studied group of patients there was no proper pre-operative diagnostics of the rotator cuff, articular surface of the scapula, which shows the need for careful preoperative examination to determine the indications for shoulder arthroplasty and select the type of prosthesis. Unsatisfactory results of total arthroplasty related to screw migration (in case of the transacromion approach) and to the development of subacromial impingement. The conclusion about the need to narrow the indications for use of the scapular component «Ortho-P». The authors showed preference to cemented implants without a metal base. It is necessary to introduce in practice the anatomic implants of the third generation allowing the fullest play the anatomy and biomechanics of the shoulder joint

Results of the proximal humerus endoprosthetic reconstruction after tumour resection

The purpose of the study was to evaluate the results of surgical reconstructions of the proximal humerus after transarticular tumour resection, compare the functional results with the results of shoulder arthroplasty in patients with extensive damage of the proximal humerus of non-neoplastic origin. Material and methods. Between 2001 and 2013 38 proximal humeral reconstructions were performed in our clinic: using monopolar endoprostheses - 26 (68%) and modular systems with reversible head -12 (32%). The control group included 46 patients with extensive lesions of the proximal humerus of non-neoplastic origin, operated in our clinic in the period from 2006 to 2012. Term follow-up of patients ranged from 7 months to 9 years. Assessment of functional results was carried out in a period from six months to one year. Results. The seven-year survival according the Kaplan - Meier method for patients with primary malignant tumors of the proximal humerus (25 patients) was 77%. In the study group the average value of functional outcome MSTS score was 77.7%. Unipolar prosthesis showed a bad result, both in the control (61,3% MSTS, 60,7 Neer) and in the main (67,7% MSTS, 61,1 Neer) study groups. Conclusion. Currently the method of choice which doesn’t impair the oncologic component of treatment patients with shoulder neoplastic lesions is its replacement with modular reversible systems in combination with additional soft tissue fixation

A new aproach to the treatment of cervix uteri patholog

The paper dedicated to treatment of exophytic cervical warts in case of cervix deformity. The results obtained allow us to recommend the reconstructive plastic surgery in combination with laser destruction of exophytic warts and immunomodulation therapy for the treatment of exophytic cervical warts in case of cervix deformity

Venous thrombosis in patients after intracardial catheter interventions: incidence, risk factors, special aspects of the diagnosis

Rationale: Thrombosis of the puncture site in the femoral veins is one of the potentially dangerous complications of intracardial catheter interventions associated with thromboembolic risk related to its proximal location. According to the literature, the incidence of symptomatic venous thrombosis (VT) is 1–3%. No special studies on the assessment of risk factors for this complication, its diagnosis and treatment have been conducted.Aim: To study the incidence, risk factors and special aspects of VT diagnosis in patients undergoing intracardial electrophysiological studies (EFI) and/or catheter ablation.Materials and methods: This prospective study included 408 patients (194  men and 214  women, with median age of 51±10.1 years), who were admitted to the hospital with various cardiac rhythm disorders for intracardial EFIs and/or catheter ablations from 2016 to 2018. Before the interventions, in addition to common laboratory and instrumental work-up, all the patients underwent ultrasound duplex scanning (USDS) of the iliac-femoral segment; in 269  patients the level of D-dimer was measured. Latest at 24 hours after the intervention, all patients underwent a control ultrasound scan of the femoral vein puncture site. In case of VT occurrence anticoagulant therapy was started in all patients and they were followed up till complete VT resolution and at least for 3  months (the study endpoint). The VT incidence and its risk factors including the prognostic value of D-dimer levels were evaluated.Results: The VT incidence after catheter interventions was 11.7% (n=48). There was a significant correlation between VT occurrence and such risk factors as diabetes mellitus (p=0.001) and obesity (p<0.001). No association between elevated baseline D-dimer values (>500 ng/mL) and subsequent VT development was found (p>0.05). The quartile analysis revealed an association between baseline D-dimer levels exceeding 434  ng/mL (which corresponds to the range of 75 to 100%) and the presence of the following risk factors: age over 65  years (p<0.001), female gender (p=0.001), arterial hypertension (p=0.003), chronic coronary heart disease (p=0.044).Conclusion: In this study, all VTs (11.7%) detected after catheter transvenous interventions by USDS were asymptomatic. VTs were most frequent in patients with diabetes mellitus and obesity. D-dimer had no predictive value in the development of VT; however, its increased baseline values were more common in women, patients over 65 years, and in patients with arterial hypertension and chronic coronary heart disease

COMPARISON RESULTS OF THE INTRACARDIAC ELECTROPHYSIOLOGICAL STUDY IN PATIENTS WITH TYPICAL ATRIAL FLUTTER AND FIBRILLATION

Aim. Comparison study of the parameters of intracardiac electrophysiological study (EPS) in patients with the typical atrial flutter (TAF) and atrial fibrillation (AF), of the courses as isolated types of arrhythmia.Material and methods. Totally, 82 patients included (59 (72%) males, mean age 55±10 y.o.), directed for catheter ablation procedure for TAF or AF. Depending on the anamnesis of arrhythmia, patients were selected to 4 groups: 1 — isolated TAF (n=26, 32%), 2 — AF with “spontaneous” TAF (n=27, 33%), 3 — AF and TAF, when the latter had been registered only under treatment by antiarrhythmics of IC and III classes (n=14, 17%), 4 — isolated AF (n=15, 18%). All patients underwent EPS within sinus rhythm and no antiarrhythmic therapy. During EPS the following parameters were defined: P-wave duration, time of interand intra-atrial conduction, effective refractory periods (ERP) in various areas of the atria. By the results of EPS, comparative statistical study performed of the listed parameters in the groups.Results. Patients with TAF (groups 1, 2, 3), in difference with isolated AF (group 4) had significantly longer P-wave and inter-atrial conduction time. Analysis of ERP showed similar heterogeneity of the parameters in different areas of the atria in all studied groups: the lowest ERP is found in the lateral area of the right atrium, the highest — in the distal area of coronary sinus. Intergroup differences by these parameters were non-significant.Conclusion. For TAF patients, as an isolated disorder or with AF, the characteristical is significant prolongation of the inter-atrial conduction time, that might expain tendency to tachiarrhythmias of re-entry genesis