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1.
Choimaa Dulamsuren Tobias Wommelsdorf Fengjun Zhao Yaoqin Xue Bulat Z. Zhumadilov Christoph Leuschner Markus Hauck 《Ecosystems》2013,16(8):1536-1549
The larch forests at the southern limit of the Siberian boreal forest in Central Asia have repeatedly experienced strong recent growth declines attributed to decreasing summer precipitation in the course of climate warming. Here, we present evidence from the southernmost Larix sibirica forests in eastern Kazakhstan that these declines are primarily caused by a decrease in effective moisture due to increasing summer temperatures, despite constant annual, and summer precipitation. Tree-ring chronologies (>800 trees) showed a reduction by 50–80% in mean ring width and an increase in the frequency of missing rings since the 1970s. Climate-response analysis revealed a stronger (negative) effect of summer temperature (in particular of the previous year’s June and July temperature) on radial growth than summer precipitation (positive effect). It is assumed that a rise in the atmospheric vapor pressure deficit, which typically increases with temperature, is negatively affecting tree water status and radial growth, either directly or indirectly through reduced soil moisture. Larch rejuvenation ceased in the 1950s, which is partly explained by increasing topsoil desiccation in a warmer climate and a high drought susceptibility of larch germination, as was demonstrated by a germination experiment with variable soil moisture levels. The lack of regeneration and the reduced annual stem increment suggest that sustainable forest management aiming at timber harvesting is no longer feasible in these southern boreal forests. Progressive climate warming is likely to cause a future northward shift of the southern limit of the boreal forest. 相似文献
2.
Pharmacokinetics of kanamycin was studied after its targeted delivery to the liver in autological erythrocyte ghosts on 25 noninbred dogs with experimental acute cholecystitis in comparison to the routine intravenous administration of the antibiotic in solution. Kanamycin concentrations in the tissues of the liver, pancreas, spleen, kidneys and lungs as well as in bile and blood serum were determined by the agar diffusion method 24, 48 and 72 hours after the last administration. It was found that the targeted delivery of kanamycin in blood shadows made it possible to provide high concentrations of the antibiotic for prolonged periods in the liver and biliary ducts and to more efficiently arrest the clinical manifestations of acute cholecystitis as well as normalize the laboratory indices. The data showed that using blood shadows as a reliable system for targeted delivery of antibiotics to the liver was advisable in purulent inflammatory affections of the biliary ducts. 相似文献
3.
Land CE Zhumadilov Z Gusev BI Hartshorne MH Wiest PW Woodward PW Crooks LA Luckyanov NK Fillmore CM Carr Z Abisheva G Beck HL Bouville A Langer J Weinstock R Gordeev KI Shinkarev S Simon SL 《Radiation research》2008,169(4):373-383
Settlements near the Semipalatinsk Test Site (SNTS) in northeastern Kazakhstan were exposed to radioactive fallout during 1949-1962. Thyroid disease prevalence among 2994 residents of eight villages was ascertained by ultrasound screening. Malignancy was determined by cytopathology. Individual thyroid doses from external and internal radiation sources were reconstructed from fallout deposition patterns, residential histories and diet, including childhood milk consumption. Point estimates of individual external and internal dose averaged 0.04 Gy (range 0-0.65) and 0.31 Gy (0-9.6), respectively, with a Pearson correlation coefficient of 0.46. Ultrasound-detected thyroid nodule prevalence was 18% and 39% among males and females, respectively. It was significantly and independently associated with both external and internal dose, the main study finding. The estimated relative biological effectiveness of internal compared to external radiation dose was 0.33, with 95% confidence bounds of 0.09-3.11. Prevalence of papillary cancer was 0.9% and was not significantly associated with radiation dose. In terms of excess relative risk per unit dose, our dose-response findings for nodule prevalence are comparable to those from populations exposed to medical X rays and to acute radiation from the Hiroshima and Nagasaki atomic bombings. 相似文献
4.
Zhumadilov K Stepanenko V Ivannikov A Zhumadilov Z Zharlyganova D Toyoda S Tanaka K Endo S Hoshi M 《Radiation and environmental biophysics》2008,47(4):541-545
The contribution of radiation from X-ray baggage scans at airports on dose formation in tooth samples was investigated by
electron spin resonance (ESR) dosimetry and by glass dosimetry. This was considered important, because tooth samples from
population around the Semipalatinsk Nuclear Test Site (SNTS), Kazakhstan, had been transported in the past to Hiroshima University
for retrospective dose assessment of these residents. Enamel samples and glass dosimeters were therefore examined at check-in
time at Kansai airport (Osaka, Japan), Dubai airport (Dubai, United Arab Emirates) and Domodedovo airport (Moscow, Russia).
These airports are on the route from Kazakhstan to Japan. Three different potential locations of the samples were investigated:
in pocket (without X-ray scans), in a small bag (with four X-ray scans) and in large luggage (with two X-ray scans). The doses
obtained by glass and ESR dosimetry methods were cross-compared. As expected, doses from X-ray examinations measured by glass
dosimetry were in the μGy range, well below the ESR detection limit and also below the doses measured in enamel samples from
residents of the SNTS. 相似文献
5.
6.
Kassym Zhumadilov Alexander Ivannikov Dinara Zharlyganova Zhaxybay Zhumadilov Valeriy Stepanenko Kazbek Apsalikov Mohd Rodzi Ali Anara Zhumadilova Shin Toyoda Satoru Endo Kenichi Tanaka Tetsuji Okamoto Masaharu Hoshi 《Radiation and environmental biophysics》2009,48(4):419-425
The method of electron spin resonance (ESR) dosimetry has been applied to human tooth enamel, to obtain individual absorbed doses of residents of settlements in vicinity of Ust-Kamenogorsk city, Kazakhstan (located about 400 km to the east from the epicenter of explosion at the Semipalatinsk Nuclear Test Site, SNTS). This region developed as a major mining and metallurgical center during the Soviet period (uranium production). Most of the investigated settlements (Ust-Kamenogorsk city, Glubokoe, Tavriya, Gagarino) are located near the central axis of the radioactive fallout trace that originated from the surface nuclear test on 24 August 1956, while the Kokpekty settlement (located 400 km to the Southeast from SNTS) was chosen as a control because it was not subjected to any radioactive contamination. In total, 44 samples were measured. It was found that the excess doses obtained after subtraction of natural background radiation ranged up to about 114 mGy for residents of Ust-Kamenogorsk city, whose tooth enamel was formed before 1956. For residents of Gagarino, excess doses did not exceed 47 mGy for all ages. For residents of Tavriya, the maximum excess dose was 54 mGy, while for residents of Glubokoe it was about 58 mGy. For the population of the Shemonaikha settlements located at a distance of about 70 km from the central axis of the radioactive fallout trace, highest excess doses were 110 mGy. These high doses may be due to the influence of uranium enterprises located in that region, but probably not due to dental X-ray irradiation. For a final conclusion on the radiological situation in this region, the number of samples was too small and, therefore, more work is required to obtain representative results. 相似文献
7.
Features of incorporation of cefazolin, ampicillin, kanamycin and gentamicin into erythrocytic shadows in patients with abdominal diseases and apparently healthy persons during hypoosmotic hemolysis were studied. The highest percentage of kanamycin and gentamicin incorporation into the erythrocytic shadows was observed. The parameter of the antibiotic incorporation from the incubation fluid into the erythrocytic shadows depended on the antibiotic type and dose. Rather significant resistance of the erythrocytic carriers with incorporated gentamicin to possible desorption and excretion of the antibiotic from the shadows into the blood flow was revealed which made their use possible for target release of antibiotics in the liver. 相似文献
8.
Vladimir Drozdovitch Sara Schonfeld Kuat Akimzhanov Daulet Aldyngurov Charles E. Land Nickolas Luckyanov Kiyohiko Mabuchi Nancy Potischman Michael J. Schwerin Yulia Semenova Alma Tokaeva Zhaxybay Zhumadilov Andr�� Bouville Steven L. Simon 《Radiation and environmental biophysics》2011,50(1):91-103
The relationship between radiation exposure from nuclear weapons testing fallout and thyroid disease in a group of 2,994 subjects has been the subject of study by the US National Cancer Institute. In that study, radiation doses to the thyroid were estimated for residents of villages in Kazakhstan possibly exposed to deposition of radioactive fallout from nuclear testing conducted by the Soviet Union at the Semipalatinsk Nuclear Test Site in Kazakhstan between 1949 and 1962. The study subjects included individuals of both Kazakh and Russian origin who were exposed during childhood and adolescence. An initial dose reconstruction used for the risk analysis of Land et al. (Radiat Res 169:373?C383, 2008) was based on individual information collected from basic questionnaires administered to the study population in 1998. However, because data on several key questions for accurately estimating doses were not obtained from the 1998 questionnaires, it was decided to conduct a second data collection campaign in 2007. Due to the many years elapsed since exposure, a well-developed strategy was necessary to encourage accurate memory recall. In our recent study, a focus group interview data collection methodology was used to collect historical behavioral and food consumption data. The data collection in 2007 involved interviews conducted within four-eight-person focus groups (three groups of women and one group of men) in each of four exposed villages where thyroid disease screening was conducted in 1998. Population-based data on relevant childhood behaviors including time spent in- and outdoors and consumption rates of milk and other dairy products were collected from women??s groups. The data were collected for five age groups of children and adolescents ranging from less than 1?year of age to 21?years of age. Dairy products considered included fresh milk and other products from cows, goats, mares, and sheep. Men??s focus group interviews pertained to construction materials of houses and schools, and animal grazing patterns and feeding practices. The response data collected are useful for improving estimates of thyroid radiation dose estimates for the subjects of an ongoing epidemiological study. 相似文献
9.
Rodzi M Zhumadilov K Ohtaki M Ivannikov A Bhattacharjee D Fukumura A Hoshi M 《Radiation and environmental biophysics》2011,50(3):451-458
Background radiation dose is used in dosimetry for estimating occupational doses of radiation workers or determining radiation
dose of an individual following accidental exposure. In the present study, the absorbed dose and the background radiation
level are determined using the electron spin resonance (ESR) method on tooth samples. The effect of using different tooth
surfaces and teeth exposed with single medical X-rays on the absorbed dose are also evaluated. A total of 48 molars of position
6–8 were collected from 13 district hospitals in Peninsular Malaysia. Thirty-six teeth had not been exposed to any excessive
radiation, and 12 teeth had been directly exposed to a single X-ray dose during medical treatment prior to extraction. There
was no significant effect of tooth surfaces and exposure with single X-rays on the measured absorbed dose of an individual.
The mean measured absorbed dose of the population is 34 ± 6.2 mGy, with an average tooth enamel age of 39 years. From the
slope of a regression line, the estimated annual background dose for Peninsular Malaysia is 0.6 ± 0.3 mGy y−1. This value is slightly lower than the yearly background dose for Malaysia, and the radiation background dose is established
by ESR tooth measurements on samples from India and Russia. 相似文献
10.
Kazuko?Shichijo Nariaki?FujimotoEmail author Darkhan?Uzbekov Ynkar?Kairkhanova Aisulu?Saimova Nailya?Chaizhunusova Nurlan?Sayakenov Dariya?Shabdarbaeva Nurlan?Aukenov Almas?Azimkhanov Alexander?Kolbayenkov Zhanna?Mussazhanova Daisuke?Niino Masahiro?Nakashima Kassym?Zhumadilov Valeriy?Stepanenko Masao?Tomonaga Tolebay?Rakhypbekov Masaharu?Hoshi 《Radiation and environmental biophysics》2017,56(2):203-204