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The results for external quantum efficiency degradation of two types of light emitting diodes based on III-nitrides: blue and ultraviolet ones are presented. Existing mechanisms proposed for the degradation are considered briefly. Applying several techniques for studying the light emitting diodes at various stages of the aging test gives the possibility to reveal a new mechanism of defects formations with a help of multi-phonon recombination of carriers in an extended defects system and in local regions of random alloy fluctuations. These techniques include analysis of current voltage characteristics evolution at V

It was recorded that hepatobiliary system disorders, which are associated with lipid storage disorders, in children became morefrequent over the last years. The above-stated pathology in childhood is understudied and little-known among practitioners. Background: To study changing rules of lipid metabolism for diagnostics development and prevention of hepatobiliary system disorders associated with dyslipidemia. Patients and methods: 53 children aged 2 to 17 years divided in 3 groups were examined: the 1st — 16 persons with familial hypercholesterolemia and disorders in hepatobiliary system; the 2nd — 11 children with liver glycogenoses; the 3rd — 26 patients with chronic cholecystitis. Results: Changing rules of lipid metabolism showed: in the 1st group — persistent hypercholesterolemia and rise in level of low-density lipoproteins; in the 2nd — combination of hypercholesterolemia with hypertriglyceridemia in roughly the instances, free fatty acids over limits; in the 3rd — decrease in the level of phospholipids in blood serum and (due to BMI > 20 kg/m2) hyperleptinemia. Conclusion: Disorders in the level of phospholipids and free fatty acids in blood serum may be used additional criteria for diagnostics of chronic cholecystitis and liver disease in children, as well reason for prescription of essential phospholipids in therapeutic sequence.