An Electrical Method for Acoustic Resonance Frequency Adjustment in Standing-Wave Acousto-Optic Devices.

An acousto-optic (AO) device can be configured to operate in a standing wave (SW) mode. The effectiveness of an SW AO device surpasses the effectiveness of a conventional, running-wave one, when the driving signal frequency meets the SW condition. This SW frequency depends primarily on the acoustic wave velocity and the crystal length.

Control of Acousto-Optic Mode Locker by Means of Electronic Matching Circuit.

An acousto-optic mode locker (AOML) operating in a standing wave mode has a fixed working frequency, defined by the length of the crystal, which makes the device prone to temperature variations. In this study, we examine the effect of the electrical matching circuit parameters on the acoustic resonances and AO diffraction in the AOML both theoretically and experimentally. Acoustical and electrical models of the AOML are introduced.

[Thymus and adaptive changes of bone marrow cell composition in animals of different age].

The influence of thymus removal or administration of thymalin, thymic peptide factor, on number of cells-precursors for colonies of fibroblasts (CFC-F) and for granulocyte-macrophageal colonies (CFC-GM), CD(4+)-cells in bone marrow in CBA mice of different age in some seasons was investigated. It was shown that in adult mice the orientation of influence thymic activity modulation on amount of these types cells is dependent from seasons. It was shown the season possibility of direct effect of thymic stroma supernatant, in which was thymic serum factor (FTS), or the synthetic FTS on the amount of CFC-F and CFC-GM in bone marrow of adult mice; in old mice thymic supernatant increased in vitro the amount of CD(4+)-cells.

[Normalizing effect of the pineal gland peptides on the daily melatonin rhythm in old monkeys and elderly people].

In the course of aging both monkeys and people reveal decreased night and average daily level of melatonin in the blood plasma and reduced hormone circadian rhythm amplitude, which evidence the disorder of the pineal gland melatonin releasing function. Peptide preparations of the pineal gland (Epithalamin--a complex of peptides isolated from the pineal gland and Epitalon--synthetic tetrapeptide) recover night release of endogenous melatonin and lead to the normalization of the hormone circadian rhythm in the blood plasma. In elderly people Epithalamin and Epitalon modulate pineal gland functional state: people with pineal gland functional insufficiency report an increase of night melatonin level.

[Circadian rhythms of pineal gland melatonin-forming function in healthy elderly people].

Circadian rhythms of pineal gland melatonin-forming function were studied in healthy elderly people (n=31, age range 60-74 years). The blood plasma melatonin concentration was determined by means of radioimmune method at 3.00, 9.