High dose rates obtained outside ISS in June 2015 during SEP event.

The R3DR2 instrument performed measurements in the European Space Agency (ESA) EXPOSE-R2 platform outside the Russian "Zvezda" module of the International Space Station (ISS) in the period 24 October 2014-11 January 2016. It is the Liulin-type deposited energy spectrometer (DES) (Dachev et al., 2015a). Took place in November 2014, this was the first attempt to monitor a small solar energetic particle (SEP) event outside ISS using the Liulin-type DES (Dachev et al., 2015d). In this study, we describe the dosimetric characteristics of the largest SEP event, observed on 22 June 2015 with the R3DR2 instrument outside ISS. The main finding of this study is that SEP protons with a minimum energy of approximately 7MeV at the surface of the R3DR2 detector produced high dose rates, reaching >5000µGyh(-1), while the inner radiation belt maximum dose was at the level of 2200µGyh(-1). If a virtual external vehicle activity (EVA) was performed in the same period of the SEP maximum on 22 June 2015, the doses obtained in the skin of cosmonauts/astronauts can reach 2.84mGy after 6.5h, which is similar to the average absorbed dose inside ISS for 15days (Reitz et al., 2005). A comparison with other extreme events measured with Liulin-type instruments shows that SEPs similar to that observed on 22 June 2015 could be one of the most dangerous events for the cosmonauts/astronauts involved in EVA.

Overview of the Liulin type instruments for space radiation measurement and their scientific results.

Ionizing radiation is recognized to be one of the main health concerns for humans in the space radiation environment. Estimation of space radiation effects on health requires the accurate knowledge of the accumulated absorbed dose, which depends on the global space radiation distribution, solar cycle and local shielding generated by the 3D mass distribution of the space vehicle. This paper presents an overview of the spectrometer-dosimeters of the Liulin type, which were developed in the late 1980s and have been in use since then. Two major measurement systems have been developed by our team. The first one is based on one silicon detector and is known as a Liulin-type deposited energy spectrometer (DES) (Dachev et al., 2002, 2003), while the second one is a dosimetric telescope (DT) with two or three silicon detectors. The Liulin-type instruments were calibrated using a number of radioactive sources and particle accelerators. The main results of the calibrations are presented in the paper. In the last section of the paper some of the most significant scientific results obtained in space and on aircraft, balloon and rocket flights since 1989 are presented.

[Psychophysiological and clinical criteria in predicting possibilities of vocational training of adolescents with mild mental retardation: use of instrumental methods]. / Psikhofiziologicheskie i klinicheskie kriterii prognoza vozmozhnostei professional'nogo obucheniia podrostkov s legkoi umstvennoi otstalost'iu s pomoshch'iu instrumental'nykh metodov.

The paper deals with the topical aspects of using instrumental psychophysiological means of assessing higher cortical functions during a medical and pedagogical process of vocational training of psychoneurological disabled individuals.

The dose rate observed on 19-21 October 1989 and its modulation by geophysical effects.

The Liulin dosimeter-radiometer on the MIR space station detected the 19 October 1989 high energy solar proton event. These results show that the main particle increase contains protons with energies up to about 9 GeV. After the main particle onset the Liulin dosimeter observed a typical geomagnetic cutoff modulation of the dose rate from the solar particles as the MIR space station traversed magnetic latitudes. When the interplanetary shock and associated solar plasma enveloped the earth on 20 October between 14 and 17 UT the radiation exposure increased significantly due to the lowering of the geomagnetic cutoff. The analysis of this event shows how various geophysical phenomena can significantly modulate the dose rate encountered by earth-orbiting spacecraft.

"Mir" radiation dosimetry results during the solar proton events in September-October 1989.

Using data from dosimetry-radiometry system "Liulin" on board of "Mir"-space station the particle flux and doserate during September-October, 1989 has been studied. The orbit of the station was 379 km perigee, 410 km apogee and 51.6 degrees inclination. Special attention has been paid to the flux and doserate changes inside the station after intensive solar proton events (SPE) on 29 of September, 1989. The comparison between the doses before and after the solar flares shows increase of the calculated mean dose per day by factor of 10 to 200. During the SPE on the 29 of September the additional dose was 310 mrad. The results of the experiment are compared with the data for the solar proton fluxes obtained on the GOES-7 satellite.

Modeling of the radiation exposure during the flight of the second Bulgarian cosmonaut on board the Mir Space Station.

An experiment involving active detection of space radiation was carried out in the Space Research Institute (SRI) of Bulgarian Academy of Sciences, in preparation of the flight of the second Bulgarian cosmonaut. The radiations that would be encountered on the flight were modelled including solar and galactic cosmic rays and the particle radiation in the Earth's radiation belts. The dose rate was calculated for these different radiations behind the shielding of the space station. The variations in dose rates over the period of the flight were calculated and compared with measurements made during the orbit of the Mir Space Station. The calculated and measured dose rates agreed within 15-35%.

[Transplantation of embryos in sheep breeding]. / Transplantatsiia na embrioni v ovtsevudstvoto.

Intra- and inter-breed transplantations were carried out with Bulgarian fresh embryos and with frozen embryos imported from Poland. A complex biotechnology was worked out, including methods of estrus synchronization, of inducing superovulation, and of producing, morphologic evaluation, storing, and transplantation of sheep embryos. Discussed are the possibilities of using embryo transplantation in sheep breeding for the fuller use of the reproductive potential of elite ewes as donors of embryos, for the introduction of new genotypes by means of importing frozen embryos as well as a modern model for fundamental investigations in the reproductive and cell biology.

[Possibilities of inducing superovulation and obtaining zygotes for transplantation in sheep]. / Prouchvaniia vurkhu vuzmozhnostite za predizvikane na superovulatsiia i poluchavane na zigoti za transplantatsiia pri ovtse.

The possibilities were explored of inducing superovulation and obtaining of zygotes from ewes of the Romanov and Tsigai breeds. The pattern used of inducing superovulation included stimulation with the serum gonadotropin preparation Gravohormone applied at the rates of 750 and 1000 IU, estrus synchronization with Estrumate (ICI, England), and ovulation with the use of the choriogonadotropin preparation Gonabion (Jenapharm, DDR). With Romanov sheep both doses of Gravohormone did not affect essentially the ovarian activity--3.4 and 3.7 ovulations were induced, whereupon a total of 5 (20%) and 10 (38%) ova were obtained from all groups of 7 animals each, 3, resp., 2 only of the zygotes being considered of high quality. With Tsigai sheep a differential ovarian response was induced--3.4 and 6.6 ovulations were produced, whereupon 5 (29%) and 15 (35%) ova were obtained, 2, resp., 7 of them being fertilized, but only 2 of the zygotes being considered fit for transplantation from the group treated with 750 IU of the preparation. No substantial differences were established in the blood plasma estradiol-17 beta and progesterone content and dynamics with the two groups of Romanov sheep treated for superovulation. Results showed that the low response of Romanov sheep, the insufficient fertilization of ova, and the low percent of zygotes capable for transplantation should be further discussed.

[Experiments with embryo transplantation in cattle in Bulgaria]. / Opiti za transplantatsiia na embrioni pri goveda u nas.

Summarized are the results of the first attempts to transplant embryos in cattle in this country over the 1979-1982 period. An average of 6.4 ovulations have been obtained by the induction of superovulation in 48 donor heifers with the use of gonadotropic preparations (Gestyl, Anteron, Folligon) in the middle of the luteal phase at dose of 2000-2500 IU as well as with prostaglandine preparations (Estrumate, Oestrophan) injected 48 hours later. Surgical and nonsurgical methods were employed to recover a total of 78 ova (25 per cent of those that ovulated). Sixty-one (78 per cent) of them were fertilized. Forty-seven (77 per cent) of these were classified as suitable for transplantation. The surgical transplantation of 46 embryos at the age of 7 days (either morula or blastocyst) in 30 synchronized recipient heifers resulted in 9 cases of pregnancy. Three calves were live born.

[Control of sex cycle functions in sheep using cloprostenol, an analog of prostaglandin F2a]. / Kontrolirane na polovotsiklichnite funktsii pri ovtsete s analoga na prostaglandin F2a-kloprostenol.

Studied was the synchronizing effect of the prostaglandin F2a analague - estrumate (ICI, England). with the Tsigai sheep. The investigations included observations on the clinical characteristics of the estrus, determination of the hormonal profile in naturally manifested estrus and in estrus induced with prostaglandin, and the conception rate with the first two successive estrus cycles along with the total conception. Estrumate was used twice ar a 9-day interval in a single dose of 125 mg, with a following programmed artificial insemination at the 48 h and the 72d hour after the second treatment. The conception rate with the first estrus of the ewes of the control and the test group was comparatively low - 41.3 and 30.4 per cent, and with the two successive cycles - 68.5 and 76.8 per cent, respectively. The total conception of the test group was 96.4 per cent as against 87.5 per cent of the control group. The studies on the content and dynamics of the basic hormones taking part in the endocrine regulation of the cycle functions in sheep with naturally manifested estrus and those with prostaglandine-unduced estrus did not show reliable differences in the hormonal profile. It was found that estrumate could successfully be used to synchronized the estrus cycle with the Tsigai sheep - a breed with pronounced conservatism' in the manifestation of cyclic functions.

Changes in plasma oestradiol-17beta, progesterone, testosterone, LH and fertility after treatment with I.C.I. 80, 996.

Fifty heifers were twice injected with I.C.I. 80, 996 and inseminated 72 h and 96 h after the second administration. Twenty eight of them (56%) became pregnant. Changes in plasma oestradiol-17 beta, progesterone and LH concentrations around the oestrus following the second injection were similar to those occurring in spontaneous oestrus. The pattern of testosterone secretion resembled that of oestradiol;-17 beta. The highest testosterone concentration (135 +/- 24 pg/ml) was measured on the third day after treatment with I.C.I. 80, 996.

[Estrogenic activity of some lucerne varieties]. / Vurkhu estrogennati aktivnost na niakoi sortove liutserna.

Studies was the estrogenic activity of lucerne--the local population Dounavka, the zonated French variety Du Puits, the promising Bulgarian variety. Pleven 1, the population Boinitsa, and the French variety Du Poitou. The estrogenic activity was determined by the biologic method based on the increase in the uterus weight of infantile mice after treatment with estrogens. Paper chromatography tests were also carried out to establish the presence of genestein and cumestrol. The study comprised three consecutive years, the extent of estrogenic activity being dependent on the amount of annual precipitations and the yields of green mass and dry matter. The study revealed that there were variations in the estrogenic activity of the investigated varieties and populations of lucerne within a wide range depending on the year of use and the green mass and dry matter obtained. High was it in the local population Dounavka, the French variety Du Poitou, and the Bulgarian variety Pleven 1. Comparatively lower was the estrogenic activity in Du Puits, and the local population Boinitsa. In all varieties and populations studied genestein was found in the first swath, and cumestrol--in the second swath. The remaining swaths showed differences in the content of genestein and cumestrol in the individual varieties and populations.

[Effect of several factors on the estrogen activity of lucerne]. / Vliianie na niakoi faktori vurkhu estrogennata aktivnost na liutsenata

Investigations were carried out on the estrogen activity of lucerne from various mowings harvested in years of different climate, studying the effect of age and yield of the crop. The observations were made during three successive years on local populations of lucerne grown under nonirrigation conditions. The estrogen activity was determined ny Bikov's biologic method, and the presence of cumestrol and genestein was established through chromatography. It was found that the estrogen activity of lucerne was to a large extent dependent on the intensity of growth. Young plants giving higher yield of green mass and dry matter manifested higher estrogen activity. Highest was the activity of lucerne from the first mowing, gradually decreasing in each of the following mowings. Variations were likewise established in the content of genestein and cumestrol in dependence on the mowing itself and the yield. All samples demonstrated that genestein was present in the first and fourth mowing, while the content of cumestrol varied within a wide range showing no markedly expressed correlations. The activity of the local lucerne populations during the first years of using the crop and the first mowings of green mass was shown to bring about disturbances in the reproduction process of ruminant animals provided lucerne is offered for a long time in greater amounts.

[Effect of a gestagen used for the induction of synchronous estrus and fertilization of cattle]. / V'rkhu efekta na edin gestagen, izpolzvan za indutsirane na sinkhronen estrus i zaplozhdane pri iunitsi

The preparations Synchrosyn, Gestafortin, and Bovisynchron, having chlormadinonacetate as a common active ingredient, were used to induce synchronous estrus and fertilization in heifers. A total of 254 animals were involved belonging to the following breeds: Bulgarian Simmental, Bulgarian Red, Bulgarian Brown, and Black Pied. All three preparations were administered orally: Synchrosyn and Gestafortin were given with the forage at the rate of 10 mg chlormadinonacetate, and Bovisynchron was offered twice daily at an interval of 12 hours, rated 1 cu. cm each time, by means of a syringe (a daily dose of 20 mg clormadinonacetate).