Discontinuous Bifurcations under 2-DOF Vibroimpact System Moving

Dynamic behaviour of strongly nonlinear non-smooth discontinuous vibroimpact system isstudied. Under variation of system parameters we find the disconti nuousbi furcati onsthat are the dangerousones. It is phenomenon unique to non-smooth systems with discontinuous right-hand side. We investigate the 2-DOF vibroimpact system by numerical parameter continuation method in conjunction with shooting and Newton-Raphson methods, Wife simulate the impact by nonlinear contact interactive force according to Hertz's contact law. We find the discontinuous bifurcations by Floquet multipliers values. At such points set-valued Floquet multipliers cross the unit circle by jump that istheir moduli becoming more than unit by jump. Wealso learn the bifurcation picture change when the impact between system bodi es became the soft one due the change of system parameters, This paper is the continuation of the previous works

Primary hyperparathyroidism with PTH values within the reference range: clinical case of a patient with recurrent nephrolithiasis

Hyperparathyroidism is an endocrine disease characterized by excessive secretion of parathyroid hormone (PTH) by the parathyroid glands. Primary hyperparathyroidism (PHPT) can be diagnosed biochemically with the combination of hypercalcemia and upper-normal or elevated levels of PTH. There are few descriptions of PHPT with normal intact PTH secretion in the literature. The incidence of PHPT among patients with recurrent urolithiasis is 2–8%. We present a clinical case of diagnosing PHPT in a 64-year-old female patient with rare variant of the disease. Before establishing the diagnosis, the main patient complaints were long-term recurrent nephrolithiasis and nephrocalcinosis. Surgical treatment made it possible to achieve rapid normalization of biochemical parameters of calcium-phosphorus metabolism, increase bone mineral density in the lumbar spine, improve the general condition of the patient. This clinical case demonstrates errors and late diagnosis of PHPT associated with poor knowledge of the manifestations of hyperparathyroidism and its masks. The authors recommend to determine the concentrations of total calcium, albumin, serum levels of PTH in patients with clinical picture of PHPT, in order to exclude the disease

Analysis of radial artery occlusion causes and methods of its prevention after interventions using radial access. Results of the APRIORI study

Aim. To study predictors of radial artery occlusion (RAO) and ways to prevent it after interventions using radial access.Material and methods. The study consisted of prospective and retrospective parts. The total number of included patients was 2284. Patients undergoing interventions by radial access in various medical organizations were retrospectively considered. The prospective study included 1284 patients who were subject to interventional treatment. Patients were randomized into two groups as follows: in group 1, hemostasis was performed within 4 hours, in group 2 — >6 hours. All patients underwent a bedside Barbeau test with a pulse oximeter and an ultrasound of access arteries to determine the radial artery patency/occlusion.Results. The RAO rate in the retrospective part was 21,8%, while in the prospective one — 10,1% with long-term hemostasis and 1,4% with short-term hemostasis (p<0,001). Predictors of RAO were type 2 diabetes (odds ratio (OR), 1,9, 95% confidence interval (CI), 1,1-3,4, p=0,03) and an increase in hemostasis duration by 1 hour (OR, 1,2, 95% CI, 1,1-1,3, p<0,001). When analyzing the retrospective part, the predictors of RAO were body mass index (OR, 1,06, 95% CI, 1,02-1,09, p=0,002), female sex (OR, 0,6, 95% CI, 0,4-0,9, p=0,02), smoking (OR, 1,38, 95% CI, 1-1,91, p=0,047). The administration of statins in different dosages, as well as antihypertensive and anti-ischemic agents, did not have a significant effect on the RAO rate.Conclusion. The main predictors of RAO were type 2 diabetes, an increase in hemostasis duration, female sex, smoking, and the artery-to-introducer diameter ratio. Taking statins, anti-ischemic and antihypertensive agents does not have a protective effect on RAO rate