Dead time duration and active reset influence on the afterpulse probability of InGaAs/InP SPAD based SPDs

We perform the detailed study of the afterpulse probability's dependence in the InGaAs/InP sine-gated SPAD on the dead time and the used approach for its implementation. We have found that the comparator's simple latching can significantly reduce afterpulses' probability, even without using a dead time pulse that lowers the diode bias voltage. We have found that with a low probability of afterpulse ( 10 mus), it is sufficient to use a circuit with latching of the comparator, which will significantly simplify the development of an SPD device for applications in which such parameters are acceptable. We also proposed a precise method for measuring and the afterpulse and presented a model describing the recurrent nature of this effect. We have shown that it should not use a simple model to describe the afterpulse probability due to rough underlying physical processes. A second-order model is preferable

Вплив стресу на продуктивність та фізіологічні функції свиней

In recent decades, the intensity of the use of pigs has increased significantly. In such conditions, the body of animals is used almost to the limit of its capabilities. In this regard, the administration of many physiological functions is disrupted, the morbidity and decrease in the performance of pigs significantly increase. The increase in the level of drug use does not solve these issues. For example, the uncontrolled use of antibiotics can lead to even more significant problems - the development of antibiotic resistance. Despite this, in modern pig breeding, considerable attention is paid to the development and implementation of methods for the prevention of diseases in pigs. An important component of such activities is to ensure optimal conditions for the comfort and well-being of animals. This, in turn, implies a reduction in the negative impact of stress factors in raising and fattening pigs. The aim of our research was to get acquainted with modern literature data on the features of the influence of stressors on productivity and physiological functions of pigs. During the writing of this review article, we reviewed data from current research on the effects of stressors on the productivity and physiological functions of pigs in rearing and fattening. For this purpose, the funds of the scientific library of Bila Tserkva National Agrarian University, scientific research systems Science-Direct and PubMed were used. An important task of veterinary service of modern pig breeding complexes is to ensure optimal parameters of the microclimate, feeding quality feed, reducing the negative impact of stress factors. Ensuring proper housing conditions contributes to the improvement of qualitative and quantitative indicators of pig productivity (at slaughter, during slaughter, etc.). In this regard, we believe that a promising area of research is to study the effects of certain stressors and their combinations on the body of pigs and find methods to correct them.В останні десятиліття інтенсивність використання свиней значно збільшується. В таких умовах організм тварин використовується практично на межі своїх можливостей. У зв’язку з цим порушується координація багатьох фізіологічних функцій, значно підвищується захворюваність та знижуються показники продуктивності свиней. Підвищення рівня використання лікарських засобів не дозволяє вирішити ці питання. Наприклад, неконтрольоване використання антибіотиків може призводити до появи ще серйозніших проблем – розвитку антибіотикорезистентності. Зважаючи на це, у сучасному свинарстві значна увага приділяється розробці та впровадженню методів профілактики захворювань свиней. Важливою складовою таких заходів є забезпечення оптимальних умов комфорту та добробуту тварин. Це своєю чергою передбачає зниження негативного впливу стресових факторів під час вирощування та відгодівлі свиней. Метою нашого дослідження було ознайомлення з сучасними літературними даними про особливості впливу стресових факторів на продуктивність та фізіологічні функції свиней. Під час написання цієї оглядової статті ми ознайомилися з даними сучасних наукових досліджень щодо впливу стресових факторів на продуктивність і фізіологічні функції свиней на дорощуванні та відгодівлі. З цією метою використовували фонди наукової бібліотеки Білоцерківського національного аграрного університету, наукові пошукові системи Science-Direct та PubMed. Важливим завданням ветеринарного обслуговування сучасних комплексів з вирощування свиней є забезпечення оптимальних параметрів мікроклімату, годівля якісними кормами, зниження негативного впливу стресових факторів. Забезпечення належних умов утримання сприяє поліпшенню якісних і кількісних показників продуктивності свиней. У зв’язку з цим вважаємо, що перспективним напрямком наукових досліджень є вивчення впливу окремих стресових факторів та їхніх комбінацій на організм свиней і пошук методів їх корекції

Crossovers between superconducting symmetry classes

We study the average density of states in a small metallic grain coupled to two superconductors with the phase difference $\pi$, in a magnetic field. The spectrum of the low-energy excitations in the grain is described by the random matrix theory whose symmetry depends on the magnetic field strength and coupling to the superconductors. In the limiting cases, a pure superconducting symmetry class is realized. For intermediate magnetic fields or couplings to the superconductors, the system experiences a crossover between different symmetry classes. With the help of the supersymmetric sigma-model we derive the exact expressions for the average density of states in the crossovers between the symmetry classes A-C and CI-C.Comment: 6 page

Identification of potentially effective antiarrhythmic drugs to individualize premature ventricular contraction therapy in patients without structural cardiac changes

Aim. To individualize premature ventricular contraction (PVC) therapy in patients without structural cardiac changes by identifying potentially effective antiarrhythmic agents.Material and methods. The study included 122 patients aged 20 to 43 years without structural cardiac changes with class IV-V PVC (Rayn B. classification (1984)) and subjective arrhythmia signs. After 24-hour Holter monitoring, the selection of potentially effective antiarrhythmic agents for terminating PVC was carried out on the basis of an increase in premature beat index after the third dose compared with the initial data of >2 relative units. The accuracy of drug choice was evaluated according to 24-hour ECG monitoring after a short course of therapy for each tested antiarrhythmic agent for at least 5 days. The follow-up duration ranged from 1 to 4-5 years. The endpoint was the duration of positive antiarrhythmic effect of the drugs used.Results. In 55,74% of patients, a positive antiarrhythmic effect was detected in two agents, in 34,43% — in three, and in the rest — in four antiarrhythmic drugs. The accuracy of drug choice averaged over 90%. In 18,85% of patients, the antiarrhythmic effect of PVC therapy maintained for less than 1 year (on average 0,8±0,05 years), in other patients, from 1 year to 5 years (on average 3,7±0,09 years) (p<0,05). The duration of maintaining a positive clinical effect for 1 year or more correlated with true positive results (r=0,94), and less than 1 year — with false negative results of testing with antiarrhythmic drugs (r=0,92).Conclusion. In all patients without structural cardiac changes with PVC, a potential positive antiarrhythmic effect was detected for two or more drugs. The accuracy of choosing potentially effective drugs for terminating PVC in these patients averaged over 90%

VENTRICULAR EXTRASYSTOLIA IN PATIENTS WITH NON-ST ELEVATION ACUTE CORONARY SYNDROME: ASSESSING THE RISK OF LIFE-THREATENING VENTRICULAR ARRHYTHMIAS (CLINICO-EXPERIMENTAL STUDY)

The study aimed to assess the risk of life-threatening ventricular arrhythmias (LTVA) in patients with non-ST elevation acute coronary syndrome (ACS) and ventricular extrasystolia (VE) developing in the first 24 hours of ACS. In 46 dogs, VE with early, postponed post-depolarisation, re-entry and ischemic mechanisms was modelled. In total, 168 patients with non-ST elevation ACS and Class II-V Lawn VE were examined. All patients underwent general clinical examination as well as the assessment of late ventricular potentials (LVP), QT interval dispersion (QTd), and heart rate turbulence (HRT). In the experimental study, persistent ventricular tachycardia and/or ventricular fibrillation developed in 100%, 75%, and 85,71% of the animals with early post-depolarisation, re-entry and ischemic VE mechanisms, respectively. In the clinical study, LTVA was observed in 13,76 % of ACS patients, including 69,32 % with arrhythmia development in the first 3 days. Positive predictive value for LVP, QTd>80 ms and pathologic HRT was no more than 42%. LTVA risk could be assessed by the formula: LTVAR = А ÷ В, where LTVAR is LTVA risk in units, A – linear deviation of corrected pre-ectopic interval (ms) for at least 20 ventricular extrasystoles, calculated separately for left and right VE, and B – analysed ventricular extrasystole number (per hour). LTVAR<0,5 could be a marker of high LTVA risk, with positive predictive value of 96,34%, in non-ST elevation ACS patients with VE