Mechanical and Tribological Properties of Polytetrafluoroethylene Modified with Combined Fillers: Carbon Fibers, Zirconium Dioxide, Silicon Dioxide and Boron Nitride.

The introduction of combined fillers can effectively improve the mechanical and tribological properties of polytetrafluoroethylene (PTFE). In this work, three different types of nanosized fillers (zirconium dioxide, silicon dioxide, and boron nitride) were introduced in a carbon fiber-reinforced polymer matrix for the development of polymer composite materials (PCM). Tensile and compressive testing were carried out, and the hardness of created PCM was evaluated.

Mechanical and Tribological Properties of Polytetrafluoroethylene Composites with Carbon Fiber and Layered Silicate Fillers.

Mixtures of layered silicates (vermiculite and kaolinite) and carbon fibers were investigated as filler materials for polytetrafluoroethylene. The supramolecular structure and the tribological and mechanical properties of the resulting polymer composite materials were evaluated. The yield strength and compressive strength of the polymer increased by 55% and 60%, respectively, when a mixed filler was used, which was attributed to supramolecular reinforcement of the composites.

[Impact of radiotherapy and chemotherapy for malignancies of the head and neck on thyroidal function and structure].

Thyroid lesions after radiation and chemotherapy include thyroid tumors and thyroiditis, which occur in violation of its function, as well as secondary hypothyroidism due to damage to the pituitary region. Hereinafter, we will use the term 'chemoradiotherapy', since in the treatment of malignant neoplasms, schemes are most often used that include both radiation exposure and drug treatment, and it is almost impossible to single out the influence of each of these components individually.

[Role of ultrasound dopplerography with acute captopril test in assessment of renal hemodynamics in chronic glomerulonephritis].

Aim: To examine blood flow in renal and intrarenal arteries and its changes in the acute pharmacological test with captopril in patients with chronic glomerulonephritis (CGN).

Material And Methods: Renal circulation was studied in 50 patients with CGN using ultrasound dopplerography (USDG) of renal vessels on the unit GE Logiq 400 CL PRO Series. The velocity and indices of peripheral blood resistance in the major renal artery (RA) and in intrarenal arteries were estimated.