[en] As a result of the Chernobyl accident, a vast territory of the Ukrainian Polesye is contaminated with radionuclides. Increased contents of radiocaesium have been detected in mushrooms, berries and birch sap. The concentration of radiocaesium in forestry products correlates with the density of radioactive contamination of forests. The largest effective equivalent doses of ionizing radiation among different professional groups are marked in workers whose activity is related directly to logging. The maximum factor of carcinogenic risk in them is detected. (author)

[en] In this paper, specific features of operation of the calorimeter of the IHEP-JINR Neutrino Detector on the basis of liquid scintillation counters upgraded for time of flight particle identification are described. Data acquisition system, algorithms of response reconstruction, and calibration of calorimeter counters are described in detail. Estimate of time and spatial resolution of counters is obtained on tracks of vertical cosmic muons. The averaged time resolution is σ = 1.2 ns, and the coordinate resolution is σ = 13 cm.

No abstract available

[en] Bone tissue engineering looking for an alternative solution to the problem of skeletal injuries. The method is based on the creation of tissue engineered bone tissue equivalent with stem cells, osteogenic factors, and scaffolds - the carriers of these cells. For production of tissue engineered bone equivalent is advisable to create scaffolds similar in composition to natural extracellular matrix of the bone. This will provide optimal conditions for the cells, and produce favorable physico-mechanical properties of the final construction. This review article gives an analysis of the most promising materials for the manufacture of cell scaffolds. Biodegradable synthetic polymers are the basis for the scaffold, but it alone cannot provide adequate physical and mechanical properties of the construction, and favorable conditions for the cells. Addition of natural polymers improves the strength characteristics and bioactivity of constructions. Of the inorganic compounds, to create cell scaffolds the most widely used calcium phosphates, which give the structure adequate stiffness and significantly increase its osteoinductive capacity. Signaling molecules do not affect the physico-mechanical properties of the scaffold, but beneficial effect is on the processes of adhesion, proliferation and differentiation of cells. Biodegradation of the materials will help to fulfill the main task of bone tissue engineering - the ability to replace synthetic construct by natural tissues that will restore the original anatomical integrity of the bone

[en] The increase in the incidence of thyroid cancers in children and adolescents in Ukraine following the Chernobyl accident made it necessary to compile a clinical morphological register of respective cancers. In 1986-1994 there were 339 cases registered in children and adolescents, of them 211 children (who were operated at the age under 15 years) and 128 adolescents (who were operated at the age of 15-18 years). Before the Chernobyl accident (1981-1985) in Ukraine 59 cases of thyroid cancer in children and adolescents were reported: 25 cases in children and 34 cases in adolescents. This increase has been observed since 1990. In 1981-1985 the incidence rate (number of thyroid cancers per 100000 children population) ranged 0.04 - 0.06. In 1990 this estimate was 0.23 and in 1992-1994 0.36 - 0.43, thus a 7-10 fold increase exceeding the pre-Chernobyl level. In the 5 most contaminated northern regions of Ukraine (Kiev, Chernigov, Zhitomir, Cherkassy, Rovno regions) and the city of Kiev the incidence rate was much higher. For example, in 1984 it was 3.8 in Chernigov region, 1.6 in Zhitomir region. The total 'contribution' of the above-mentioned regions to the incidence of thyroid cancer in children after the Chernobyl accident makes more than 60%. It has been noted that in 1990-1994 there was an increase in the number of children operated at the age under 10, it means that these children were under 6 years at the time of the accident and were most sensitive to radioiodine exposure. As for the sex ratio, there has been a shift to males: in 1981-1985 F/M = 1.8/1, in 1990-1994 F/M = 1.4/1. Morphologically, 93.4% of 196 carcinomas resected from children and adolescents at the Institute of Endocrinology from 1986 to August 1st, 1995 were papillary carcinomas. They manifested high invasive and infiltrative growth, signs of intraglandular spread. Regional lymph node metastases were found in 59% of cases, distal lung metastases observed at various periods after surgery were noted in 23.7% of cases

[en] Based on the linear electron accelerator LUE-75 of the A.I. Alikhanyan National Scientific Laboratory a technique for obtaining controlled primary electron beams with an intensity of (10–20) electrons per second in the energy range (15–75) MeV for elementary particle detectors calibration was developed and applied. Joint work with the V.P. Dzhelepov Laboratory of Nuclear Problems (JINR, Dubna, RF) showed the efficiency of the technique

[en] The light yield of 2-m long extruded scintillation bars (strips) are measured with cosmic muons as a function of the distance for different options of the light collection technique. The strips with a 2.6-mm diameter central co-extruded hole were made of polystyrene with the 2% PTP and 0.03% POPOP dopants at ISMA (Kharkov, Ukraine). It is shown that the optical transparent BC-600 or CKTN-MED(E) resin injected by a special technique into the co-extruded hole with a 1.0-mm or 1.2-mm Kuraray Y11 (200) MC wave-length shifting (WLS) fiber in it improves light collection by a factor of 1.6–1.9 against the ''dry'' case.

[en] The work is focused on the development of production methods of large scintillators based on lutetium-gadolinium oxyorthosilicate doped with cerium Lu_2xGd_2−2xSiO₅:Ce (LGSO:Ce). Large LGSO:Ce crystals were grown by the Czochralski method, and a set of experimental samples for testing of scintillation characteristics was produced. Possibilities are discussed to use this scintillator in high energy physics experiments. In particular, an electromagnetic calorimeter to search for conversion of electrons into muons, which is forbidden in the Standard Model. -- Highlights: • We report comparative tests of scintillation characteristics of LGSO:Ce, LSO:Ce, and LYSO:Ce crystals. • Large crackless LGSO:Ce crystals are grown by the Czochralski method. • Possibility to use this scintillator in electromagnetic calorimeter for search of electron conversion into muons is studied. • LGSO:Ce energy resolution at 662 keV is by 1.3–2.2% better compared to LSO:Ce and LYSO:Ce

No abstract available

[en] This paper describes the measurements of energy and time response and resolution of a 3×3 array made of undoped CsI crystals 3×3×20 cm"3 coupled to large area Hamamatsu Multi Pixel Photon Counters 12×12 mm"2. The measurements have been performed using the electron beam of the Beam Test Facility in Frascati (Rome, Italy) in the energy range 80–120 MeV. The measured energy resolution, estimated with the FWHM, at 100 MeV is 16.4%. This resolution is dominated by the energy leakage due to the small dimensions of the prototype. The time is reconstructed by fitting the leading edge of the digitized signals and applying a digital constant fraction discrimination technique. A time resolution of about 110 ps at 100 MeV is achieved.