Effect of gamma-irradiation on the photoluminescence of silver-doped lithium triborate glass.

Optical-luminescence properties, including absorption spectra, photoluminescence excitation spectra, and changes in photoluminescence spectra after irradiation with γ-rays in the dose range of 1-3 Gy, were measured for novel L i B 3 O 5:A g dosimeter glass. A clear dependence of the intensity of the photoluminescence (PL), with a maximum of approximately 300 nm, on the dose value when excited by light with λ e x c =220n m was observed. The mechanism of PL in γ-irradiated L i B 3 O 5:A g glass is proposed to be a consequence of radiation annihilation with the emission of relaxed exciton-like electronic excitations with the participation of impurity defects (A g 0) in the glass structure. Considering that L i B 3 O 5 has an effective atomic number of Z e f f =7.39, which is the closest to Z e f f =7.42 of human body tissue, L i B 3 O 5:A g glass can be very promising for γ-dosimetry in medical practice during radiation therapy of patients with cancer. The presence of lithium Li(6) and boron B(10) isotopes increases the sensitivity of L i B 3 O 5:A g glass to neutrons, which is promising for the manufacture of individual neutron dosimeters for applications in a new field of radiation therapy-neutron therapy.

AGE FEATURES OF THE STRUCTURE OF THE BLOOD VESSELS OF THE SOME DIGESTIVE GLANDS AND ITS RESTRUCTURING IN THE INITIAL STAGES OF EXPERIMENTAL DIABETES MELLITUS.

OBJECTIVE: The aim: The purpose of the work was to study the peculiarities of blood supply the pancreatic islet of the 24-month-old rat, and its restructuring during the initial periods of experimental diabetes mellitus. PATIENTS AND METHODS: Materials and methods: The work was performed on 20 white outbred rats - males weighing 340-420g. 24 months of age, kept in standard vivarium conditions in compliance with all accepted ethical rules. Experimental streptozotocin diabetes mellitus was simulated in 16 animals. The material was taken on the 14th and 28th day of the experiment. RESULTS: Results: Reorganization of the endocrine part of the pancreas in the early stages of experimental diabetes is characterized by a decrease in the number and area of pancreatic islets, a decrease in the diameter of the lumen of arterioles, precapillaries, postcapillaries compared to the control group of animals by 7% and 5%. The diameter of the capillaries decreases by 16% and reaches 3.8 ± 0.62 µm2, and the diameter of the venules increases by 12%. In some blood vessels there are phenomena of desolation and edema of perivascular connective tissue, which is manifested by a decrease in optical density and stratification of collagen fibers. CONCLUSION: Conclusions: Thus, the reorganization of the circulatory system of the endocrine part of the pancreas of 24-month-old rats in the early stages of experimental diabetes mellitus is characterized by a decrease in the number and area of pancreatic islets.