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This paper present comparative analysis of the characteristics for the gas insulated three-electrode spark gaps and vacuum insulated three-electrode spark gaps. The experimental part of this paper includes the testing of spark gap models. Two spark gap types were studied: one having the third electrode inside the main electrode and one having a separate third electrode, both being insulated by vacuum or gas (under pressure, providing the same operating voltage as for a vacuum insulated spark gap). Both types of spark gaps were theoretically sized in the optimal way. Several characteristics are determined experimentally: 1) the influence of the gas and vacuum insulation parameters on the spark gap functioning, 2) the influence of the rate of rise and injected energy of the triggering pulse on the spark gap functioning and 3) the degree of spark gap erosion vs. number of operations (long-time-stability). Two types of gases were applied: [SF.sub.6] gas, [N.sub.2] gas and three vacuum (residual) pressures: [10.sup.-1] Pa, [10.sup.-4] Pa, and [10.sub.-6] Pa. Also, three electrode materials were used: copper, steel and tungsten. The spark gap switching time and delay time are measured. It was found that the switching time decreases with application of pressure decrease, and the statistical dispersion of switching time raises with the pressure decrease. By comparison of results obtained for the vacuum insulated spark gap and the [SF.sub.6] or [N.sub.2] gas insulated spark gap, it was found that the vacuum spark gap has a slightly shorter switching time and a significantly higher corresponding statistical dispersion. Also, it was found that under a higher triggering time rate of rise - the switching time and its statistical dispersion increase with the triggering pulse rate of rise for the vacuum spark gap. The decrease of delay time and its statistical dispersion with rate of rise was observed. The influence of insulator or electrode materials type on delay time was not observed. For the vacuum spark gap the significant decrease of switching time and its statistical distribution with increase of injected trigger pulse energy was observed. This phenomenon exists also for gas spark gap but less significant. The most striking irreversible changes appeared in the vacuum spark gap with steel electrodes. The least irreversible changes appeared in the spark gap isolated by [N.sub.2] with tungsten electrodes.

The development of a three-electrode spark gap used with synthetic circuit is considered in this paper. Two types of three-electrode gas insulated spark gaps have been tested: a spark gap with a third electrode being inside the main electrode, and a spark gap with a separate third electrode. Both types of spark gaps were theoretically sized in the optimal way. Several characteristic are determined experimentally: 1) the influence of the gas insulation parameters on the spark gap functioning, 2) the influence of the working and triggering voltages polarities on the spark gap functioning, 3) the influence of the triggering voltage rate-of-rise on the spark gap functioning and 4) the degree of spark gap erosion vs number of operations. Three types of gases were applied: SF6 gas, N2 gas and mixture of 60% SF6 with 40% N2. Also, three electrode materials were used: copper, steel and tungsten. The spark gap switching time and delay time are measured. The statistical analysis of results is presented.

NiFe2O4 and ZnFe2O4 ferrites have been prepared by soft mechanochemical synthesis. The formation of spinel phase and crystal structure of sintered powders were analyzed by X-ray diffraction, Raman spectroscopy, and transmission microscopy. In order to confirm phase formation and cation arrangement, Mössbauer measurements were done. Investigation of the magnetization as a function of magnetic field confirms an expected change of the degree of inversion in the spinel structure with the sintering. The electrical DC/resistivity/conductivity was measured in the temperature range of 298-423 K. Impedance spectroscopy was performed in the wide frequency range (100 Hz-10 MHz) at different temperatures. [ABSTRACT FROM AUTHOR]

Background: Cardiovascular diseases (CVDs) and chronic kidney disease (CKD) are common causes of morbidity and mortality. However, the impact of changes in lifestyle and rehabilitation programs on the progression of cardiovascular, renal, and metabolic (CRM) conditions, remains unclear., Methods: In a retrospective manner, we analyzed charts of 200 patients admitted for cardiorespiratory rehabilitation at our facility in 2023. A 6 min walk test, echocardiographic features, and laboratory values were investigated to evaluate the impact of cardiorespiratory rehabilitation in patients post cardiac surgery. This study examined the impact of combined lifestyle and exercise scores (diet, alcohol consumption, smoking, aerobic physical activity, sedentary behavior, sleep duration, and social connection) on cardio-renal-metabolic profiles and on a quality-of-life score measured by the Borg Scale., Results: During the rehabilitation program, left ventricular ejection fraction (LVEF) significantly increased (51.2 vs. 54.3%, SEM 0.51 p = 0.001). The six-minute walk test (6 MWT) significantly improved in terms of meters (133 vs. 373 m, SEM 6.41, p < 0.001) and Borg scale (6.6 vs. 2.5, SEM 0.06, p < 0.001). Glycemia levels reduced significantly (114.5± vs. 107.4± mg/dL, SEM 2.45, p = 0.001). While total cholesterol levels (119.4 vs. 129.6 mg/dL, SEM 2.4, p < 0.001) as well as HDL levels (29.9 vs. 40 mg/dL, SEM 0.62, p < 0.001) significantly increased, triglyceride levels significantly decreased (128.5 vs. 122.1 mg/dL, SEM 3.8, p = 0.048). There was no change in LDL levels. Creatinine levels remained stable throughout the period of rehabilitation., Conclusions: Cardiorespiratory rehabilitation has a significant impact on myocardial function, quality of life in terms of exercise capacity and symptoms (6 MWT) as well as laboratory levels relevant for cardiovascular prevention such as glycemia and lipid profile.

Aim: To describe echocardiographically left ventricular false tendon characteristics and the correlation with ventricular repolarization abnormalities in young athletes., Methods: Three hundred and sixteen healthy young athletes from different sport disciplines were evaluated from 2009 to 2011 during routine screening for agonistic sports eligibility. All subjects, as part of standard pre-participation screening medical evaluation, underwent a basal and post step test 12-lead electrocardiogram (ECG). The athletes with abnormal T-wave flattening and/or inversion were considered for an echocardiogram evaluation and an incremental maximal exercise test on a cycle ergometer. Arterial blood pressure and heart rate, during and after exercise, were also measured., Results: Twenty-one of the 316 subjects (6.9%) showed false tendons in the left ventricle. The majority of false tendons (52.38%) were localized between the middle segments of the inferior septum and the lateral wall, 19.06% between the distal segments of the septum and the lateral wall, in 5 subjects between the middle segments of the anterior and inferior walls, and in one subject between the middle segments of the anterior septum and the posterior wall. ECG abnormalities, represented by alterations of ventricular repolarization, were found in 11 subjects (52.38%), 90% of these anomalies were T wave abnormalities from V1 to V3. These anomalies disappeared with an increasing heart rate following the three minute step test as well as during the execution of the maximal exercise., Conclusion: Left ventricular false tendons are frequently localized between the middle segments of the inferior septum and the lateral wall and are statistically associated with ventricular repolarization abnormalities., Competing Interests: Conflict-of-interest statement: There are no financial or other relationships that might lead to a conflict of interest in this study.

In 655 individuals receiving HIV postexposure prophylaxis (PEP), drug-induced aminotransferase alterations were frequent and severe in the nevirapine-including regimen, rare and mild-to-moderate in other combinations, and always reversible. Grade 3-4 incidence in protease inhibitor or nevirapine PEP was 0.5 and 25.0 per 100 person-months, respectively. Apart from nevirapine, continuing PEP appears to be safe even in the case of aminotransferase alterations. The usefulness of routine monitoring of liver function during PEP could be re-considered.

Although known since 1849 and introduced in medical practice 1955, sodium nitroprusside is used mostly in large medical centres fully equipped with monitoring equipment. This attitude has contributed that sodium nitroprusside is not as popular as it should be. An attempt is made to show that single banded practising anesthesist may and should use sodium nitroprusside to produce controlled hypotension, provided certain "safeguards" are followed. These safeguards are based on information got from the literature and own experience with sodium nitroprusside in obtaining controlled hypotension during anesthesia using sophisticated equipment as well as simplified monitoring, which is fully explained in the article.

A self made connection device with an injector of 1.5 mm in diameter and connections for the measurements of the end tidal CO2 (Datascope 500 CO2 Analyzer), expired tidal and minute volumen (Dr¿ger Spirolog), and armoured tracheal tube nr. 22 with cuff (Rüsch), has been used in 25 unselected patients submitted to diagnostic laryngoscopy. The patients have been ventilated with Wolf Injectomat 2025 with incorporated Bird's Nitrous Oxyde/Oxygen blender and general anesthesia with i.v. hypnoticum (Penthotal or Hypnomidate), analgeticum (Fentanyl) and muscle relaxant (Curalest) has been used. The patients were further monitored by means of blood pressure measurements (oscillotonometric method), simultaneous pulse count and ECG recording (Datascope 740 Recorder) and blood gases determination from a.femoralis (ABL 1, Radiometer Copenhagen).