Modulator chip based on semiconductor heterostructures with a surface diffraction grating for laser beam steering.

Design parameter optimization of a chip based on a heterostructure with a surface diffraction grating for laser beam angle modulation was carried out. It was found that the widest field of view is achieved at outcoupling angles close to the total internal reflection. The highest energy efficiency is provided by using epitaxy Bragg reflector on the substrate side.

[Transthoracic decompression of the spinal cord in herniation of thoracic intervertebral disks].

Hemiation of the thoracic intervertebral disk is a rare pathology causing a severe neurological deficit. Of all the disk hernias, thoracic ones account for less than 1%. Thirty-five patients have been operated on for 12 years, by using the following methods: posterior approach (laminectomy) (n = 2), lateral extrapleural approach (n = 8), anterior (transthoracic) approach (n = 25).

[Low-intensive laser irradiation in combined treatment of lower limbs atherosclerotic lesions].

Seventy-one subjects entered this study. The control group consisted of 12 healthy subjects, the comparative group included 15 patients who received standard therapy of vascular diseases but without physiotherapy. The study group consisted of 44 patients whose treatment was supplemented with laser irradiation.

[Reply to the letter-to-the-editors by V.A. Pitkevich, V.K. Ivanov, S.Iu. Chekin, A.F. Tsyb, "Concerning the problem of radiation exposure levels to the Chernobyl AES accident clean-up participants, included in Russian Medical-Dosimetric State Registry"].

Theoretical and practical problems related to the dosimetric data verification for recovery workers at the Chernobyl NPP are considered. The distinctions in definitions epsilon-entropy in paper [1] and delta-entropy in [2] are considered. In a certain measure this distinctions explain distinction in conclusions, made in these papers.

[The need to account for beta radiation in determining the total radiation exposure of those working in cleanup].

The role of external beta-radiation as one of the major radiation factors effected persons involved in recovery operations (liquidators) after the accident at the Chernobyl nuclear power plant is considered. The paper uses the data of discriminate individual dosimetric monitoring of beta- and gamma-radiation for different groups of liquidators and experimentally received dose distribution in tissue equivalent material in the places of carrying out work. The results obtained by calculation were also used.