Kassym Zhumadilov - Profile on Academia.edu (original) (raw)

Papers by Kassym Zhumadilov

Ceramics, 2021

The work is devoted to the study of radiation damage and subsequent swelling processes of the sur... more The work is devoted to the study of radiation damage and subsequent swelling processes of the surface layer of Li2ZrO3 ceramics under irradiation with heavy Xe22+ ions, depending on the accumulation of the radiation dose. The samples under study were obtained using a mechanochemical synthesis method. The samples were irradiated with heavy Xe22+ ions with an energy of 230 MeV at irradiation fluences of 1011–1016 ion/cm2. The choice of ion types is due to the possibility of simulating the radiation damage accumulation processes as a result of the implantation of Xe22+ ions and subsequent atomic displacements. It was found that, at irradiation doses above 5 × 1014 ion/cm2, point defects accumulate, which leads to a disordering of the surface layer and a subsequent decrease in the strength and hardness of ceramics. At the same time, the main process influencing the decrease in resistance to radiation damage is the crystal structure swelling as a result of the accumulation of defects and...

ESR dosimetry of teeth from the victims of the JCO accident

No evidence for the TRI-effect in the gray and neutron emission so far. No evidence for the TRI-e... more No evidence for the TRI-effect in the gray and neutron emission so far. No evidence for the TRI-effect in the gray and neutron emission so far. Historical background (II)

7 Graduated School 0/ Engineering. Hiroshima University. Japan 'Center 0/ Medical Education. ... more 7 Graduated School 0/ Engineering. Hiroshima University. Japan 'Center 0/ Medical Education. Sapporo Medical University, Japan 'School 0/ Dentistry. Ohu University. Koriyama-shi. Japan 10 Low Level Radioactivity Laboratory. K-INET, Kanazawa University, Japan " Graduate School 0/ Biomedical Sciences, Hiroshima University. Japan The method of electron spin resonance (ESR) dosimetry was used to human tooth enamel to obtain individual absorbed doses of population of settlements in the vicinity of the Semipalatinsk Nuclear Test Site (SNTS), Kazakhstan. The distances between investigated settlements and Ground Zero (SNTS) are in the range 70 200 km from SNTS. Most of settlements (Dol on, Mostik, Bodene) are located near the central axis of radioactive fallout trace from the most contaminating surface nuclear test, which was conducted in 29, August 1949. The other settlements located close to radioactive fallout trace as a result of surface nuclear tests in 24, August 1956 (Us...

Lop Nor Influence investigation to population of Kazakhstan

Scientific Reports, 2021

To understand the radiation effects of the atomic bombing of Hiroshima and Nagasaki among the sur... more To understand the radiation effects of the atomic bombing of Hiroshima and Nagasaki among the survivors, radiation from neutron-induced radioisotopes in soil should be considered in addition to the initial radiation directly received from the bombs. 56Mn, which emits both β particles and γ-rays, is one of the dominant radioisotopes created in soil by neutrons from the bomb. Thus we investigated the biological effects of internal exposure to 56MnO2 particle in the lung of male Wistar rats comparing to the effects of external 60Co-γ irradiation. Absorbed doses of internal irradiation of lungs were between 25 and 65 mGy in 56MnO2-exposed animals, while the whole body doses were between 41 and 100 mGy. Animals were examined on days 3 and 61 after the exposure. There were no remarkable pathological changes related to 56MnO2 particle exposure. However, mRNA and protein expressions of aquaporin 5 increased significantly in the lung tissue on day 3 postexposure in 56MnO2 groups (by 1.6 and ...

Radiation and Environmental Biophysics, 2020

The experiment was performed in support of a Japanese initiative to investigate the biological ef... more The experiment was performed in support of a Japanese initiative to investigate the biological effects of irradiation from residual neutron-activated radioactivity that resulted from the A-bombing. Radionuclide 56Mn (T1/2 = 2.58 h) is one of the main neutron-activated emitters during the first hours after neutron activation of soil dust particles. In our previous studies (2016–2017) related to irradiation of male Wistar rats after dispersion of 56MnO2 powder, the internal doses in rats were found to be very inhomogeneous: distribution of doses among different organs ranged from 1.3 Gy in small intestine to less than 0.0015 Gy in some of the other organs. Internal doses in the lungs ranged from 0.03 to 0.1 Gy. The essential pathological changes were found in lung tissue of rats despite a low level of irradiation. In the present study, the dosimetry investigations were extended: internal doses in experimental mice and rats were estimated for various activity levels of dispersed neutro...

International Journal of Molecular Sciences, 2020

To investigate the biological effects of internal exposure of radioactive 56MnO2 powder, the majo... more To investigate the biological effects of internal exposure of radioactive 56MnO2 powder, the major radioisotope dust in the soil after atomic bomb explosions, on male reproductive function, the gene expression of the testes and the prostate was examined. Ten-week-old male Wistar rats were exposed to three doses of radioactive 56MnO2 powder (41–100 mGy in whole body doses), stable MnO2 powder, or external 60Co γ-rays (2 Gy). Animals were necropsied on Days 3 and 61 postexposure. The mRNA expressions of testicular marker protein genes and prostatic secretory protein genes were quantified by Q-RT-PCR. On Day 3 postexposure, the testicular gene expressions of steroidogenesis-related enzymes, Cyp17a1 and Hsd3b1, decreased in 56MnO2-exposed groups. Germ cell-specific Spag4 and Zpbp mRNA levels were also reduced. On postexposure Day 61, the Cyp11a1 gene expression became significantly reduced in the testes in the group exposed to the highest dose of 56MnO2, while another steroidogenesis-re...

Machine learning for determination of the native background EPR signal amplitude in the teeth enamel

Radiation Measurements, 2020

Abstract The measurement of teeth in vivo (i.e., in the mouth, without extraction) with EPR spect... more Abstract The measurement of teeth in vivo (i.e., in the mouth, without extraction) with EPR spectroscopy in the L-band would allow to screen large groups of population in an event of an acute radiation exposure and in routine epidemiological studies. The radiation dose is proportional to intensity of the radiation-induced signal amplitude determined after subtraction of both native and solar light induced signal amplitudes from the total signal amplitude measured in L-band. Therefore, to improve the dose assessments of in vivo tooth dosimetry a better accuracy of native background signal is necessary. In this work, we present a search for the optimal machine learning approach for predicting of intensity of the native signal amplitude. The study used the dataset from two institutes composed of 1800 EPR spectra which were recorded in the X-band at a large-scale examination of the population of the Central Russia and North Kazakhstan. To determine the relevance of 12 various features a preliminary statistical significance analysis was used. Predictive models for native signal amplitude determination were developed and trained using standard Python frameworks for machine learning and data processing. The employed algorithms included 8 most popular machine learning regressors. To tune the performance of each algorithm a common evaluation technique, namely cross-validation, was used. Finally, mean squared error and coefficient of determination were calculated for performance analysis of the employed models. Comparison among the performance of all established prediction models revealed that Random Forest and Gradient Boosting had most superior performance. Overall, the application of machine learning methods was shown to provide a minor (5–11% in terms of R2) but non negligible improvement to the accuracy of native signal amplitude prediction. Using the technique of adding synthetic noise variables, the most significant factor regarding the prediction was position of tooth in the quadrant.

E3S Web of Conferences, 2017

The tooth enamel electron paramagnetic resonance (EPR) dosimetry method was used to determine acc... more The tooth enamel electron paramagnetic resonance (EPR) dosimetry method was used to determine accidental doses of population of settlements in the vicinity of the Semipalatinsk Nuclear Test Site (SNTS), Kazakhstan. The influence of four explosions to the populations was included into this report. The distances between investigated settlements and Ground Zero (SNTS) are in the range of 70-200 km from SNTS. Most of settlements (Dolon, Mostik, Bodene, Cheremushki, Kanonerka) are located near the central axis of radioactive fallout trace from the most contaminating surface nuclear test, which was conducted in 29, August 1949. The other settlements located close to radioactive fallout trace result in a surface nuclear tests in 24, August 1956 (Ust-Kamenogorsk, Znamenka, Shemonaikha, Glubokoe, Tavriya, Gagarino), in 12 august 1953 (Sarzhal) and in 7, August 1962 (Akzhar, Kurchatov, Begen, Semenovka, Buras, Grachi). Tooth samples were extracted according to medical recommendations in a course of ordinary dental treatment.

Bulletin of the Karaganda University. "Physics" Series, 2019

Special dosimetry study of experimental rats exposure by sprayed 56 Mn powder was conducted durin... more Special dosimetry study of experimental rats exposure by sprayed 56 Mn powder was conducted during experiments in order to study internal irradiation effects. All experiments were performed in Kurchatov's reactor complex «Baikal-1» (Kurchatov city, East-Kazakhstan region) after neutron activation of stable Mn powder. This study was performed by group of scientists from Japan, Kazakhstan, and Russian Federation. The results of estimated doses in lungs alveolar epithelium of rats are shown in this paper. Absorbed dose on the «surface» of epitelium is equal to 160 Gy and absorbed dose in the «bottom» of epithelium for minimal thickness of epithelium cells is 8.9 Gy and for maximal thickness of epithelium cells equal to 0.4 Gy.

Radiation and Environmental Biophysics, 2017

The author would like to correct the Table in the original publication of the article. The correc... more The author would like to correct the Table in the original publication of the article. The correct table is given below: The online version of the original article can be found under

Radiation and Environmental Biophysics, 2017

to any additional radiation (control). On days 3, 14, and 60 after exposure, the animals were kil... more to any additional radiation (control). On days 3, 14, and 60 after exposure, the animals were killed and major organs were dissected and subjected to histopathological analysis. As described in more detail by an accompanying publication, the highest internal radiation dose was observed in the digestive system of the rats, followed by the lungs. It was found that the number of mitotic cells increased in the small intestine on day 3 after 56 Mn and 60 Co exposure, and this change persisted only in 56 Mn-exposed animals. Lung tissue was severely damaged only by exposure to 56 Mn, despite a rather low radiation dose (less than 0.1 Gy). These data suggest that internal exposure to 56 Mn has a significant biological impact on the lungs and small intestine.

EPR pilot study on the population of Stepnogorsk city living in the vicinity of a uranium processing plant

Radiation and Environmental Biophysics, 2014

The aim of this pilot study was to evaluate possible doses in teeth received by workers of a uran... more The aim of this pilot study was to evaluate possible doses in teeth received by workers of a uranium processing plant, in excess to the natural background dose. For this, the electron paramagnetic resonance dosimetry method was applied. Absorbed doses in teeth from the workers were compared with those measured in teeth from the Stepnogorsk city population and a control pool population from Astana city. The measured tooth samples were extracted according to medical indications. In total, 32 tooth enamel samples were analyzed, 5 from Astana city, Kazakhstan (control population), 21 from the residents of Stepnogorsk city (180 km from Astana city), and 6 from the workers of a uranium processing plant. The estimated doses in tooth enamel from the uranium processing plant workers were not significantly different to those measured in enamel from the control population. In teeth from the workers, the maximum dose in excess to background dose was 33 mGy. In two teeth from residents of Stepnogorsk city, however, somewhat larger doses were measured. The results of this pilot study encourage further investigations in an effort to receiving a final conclusion on the exposure situation of the uranium processing plant workers and the residents of Stepnogorsk city.

Feasibility of using 236U to reconstruct close-in fallout deposition from the Hiroshima atomic bomb

Science of The Total Environment, 2010

The first results on the feasibility of using (236)U to reconstruct the level and spatial distrib... more The first results on the feasibility of using (236)U to reconstruct the level and spatial distribution of close-in fallout deposition from the Hiroshima A-bomb are reported, coupled with the use of global fallout (137)Cs and (239+240)Pu. The results for global fallout (236)U in soil samples (0-30cm) from Ishikawa prefecture showed that the deposition density of (236)U from the global fallout can be accurately evaluated using AMS. All deposited (236)U, (137)Cs and (239+240)Pu appeared to have been recovered using 30-cm cores. It was also noted from the depth profiles for (236)U/(239+240)Pu and (236)U/(137)Cs ratios that the downward behavior of (236)U in the soil was apparently similar to that of (239+240)Pu, while the (137)Cs was liable to be retained in upper layers compared with (236)U and (239+240)Pu. The accumulated levels were 1.78×10(13)atomsm(-2) for (236)U, 4340Bqm(-2) for (137)Cs and 141Bqm(-2) for (239+240)Pu. The ratios of (236)U/(137)Cs and (236)U/(239+240)Pu were (4.10±0.12)×10(9) and (1.26±0.04)×10(11)atomsBq(-1), respectively. Results of (236)U, (137)Cs and (239+240)Pu measurements for the seven soil cores (0-30cm) from Hiroshima were discussed on the basis of ratios of (236)U/(137)Cs and (236)U/(239+240)Pu by comparing with those from the background area in Ishikawa, indicating that the global fallout dominates the current level of (236)U accumulation in soil in the Black-rain area around Hiroshima after the Hiroshima bomb, and the contribution of the close-in fallout (236)U produced by the Hiroshima A-bomb seems difficult to observe.

Radiation Measurements, 2007

For intercomparison of methods of dose determination using electron paramagnetic resonance (EPR) ... more For intercomparison of methods of dose determination using electron paramagnetic resonance (EPR) spectroscopy of tooth enamel, the same sets of enamel samples were analyzed in different laboratories using similar recording parameters. The sets of samples included calibration samples irradiated in known doses, test samples irradiated to doses unknown to the participants and accidental dose samples prepared from teeth of humans affected by radioactive fallout from nuclear tests in the Semipalatinsk Nuclear Test Site in Kazakhstan. The test samples were analyzed to determine the differences in the resulting doses using different spectrometers and different spectra processing methods. The accidental dose samples were analyzed in order to test the precision of doses determined by EPR spectroscopy and to obtain more accurate values by averaging the results from different laboratories.

Radiation Measurements, 2007

The method of electron paramagnetic resonance (EPR) dosimetry was used on human tooth enamel to o... more The method of electron paramagnetic resonance (EPR) dosimetry was used on human tooth enamel to obtain individual absorbed doses of residents of settlements in the vicinity of the Nuclear Test Site (SNTS) in Semipalatinsk region, Kazakhstan. Measured teeth were extracted according to medical indications. In total, 105 tooth enamel samples were analyzed, including eight tooth samples from control settlement Kokpekty, which is located 400 km to the Southeast from SNTS and was not subjected to any radioactive contamination. It was found that the excess doses obtained after subtraction of the contribution of natural background radiation ranged up to about 440 mGy for residents of Dolon, whose tooth enamel was formed before 1949, and do not exceed 100 mGy for younger residents. For residents of Mostik, excess doses do not exceed 100 mGy for all ages except in one resident, for whom an extremely high dose of 1250 mGy was registered. For Bodene settlement, excess doses higher than 100 mGy were obtained for two samples from the residents having enamel formed before 1949. An extremely high dose (2800 ± 400 mGy) was obtained for one resident of Semipalatinsk City. The average excess dose for Semipalatinsk samples with enamel formation before 1949 was determined close to the average excess dose for tooth enamel samples from Dolon village.

Radiation Measurements, 2011

The method of electron spin resonance (ESR) dosimetry was applied to human tooth enamel to obtain... more The method of electron spin resonance (ESR) dosimetry was applied to human tooth enamel to obtain estimates of individual absorbed dose for residents of Makanchi, Urdzhar and Taskesken settlements located near the KazakhstaneChinese border (about 400 km to the SoutheEast, from the Semipalatinsk Nuclear Test Site (SNTS) and about 1000 km from the Lop Nor Nuclear Weapons Test Base, China). Since the ground and atmospheric nuclear tests (1964e1981) at Lop Nor, the people residing in these settlements are believed to have been heavily exposed to radioactive fallout. Tooth samples had been extracted for medical reasons during the course of ordinary dental treatment. The village of Kokpekty, located 400 km to the Southeeast of the SNTS, was chosen as the control group since it has not been subjected to any radioactive contamination. The mean excess doses in tooth enamel obtained after subtraction of the contribution of natural background radiation do not exceed 62 AE 28 mGy, 64 AE 30 mGy, 49 AE 27 mGy and À19 AE 36 mGy for all ages of the residents of Makanchi, Urdzhar, Taskesken and the control village of Kokpekty, respectively.

ESR dosimetry study for the residents of Kazakhstan exposed to radioactive fallout on 24, August 1956

Radiation Measurements, 2011

The method of electron spin resonance (ESR) dosimetry has been applied to human tooth enamel in o... more The method of electron spin resonance (ESR) dosimetry has been applied to human tooth enamel in order to obtain individual absorbed doses from the population of settlements within the vicinity of the central axis of the radioactive fallout trace from the contaminating nuclear surface test of 24, August 1956. Most of the settlements (Glubokoe, Tavriya, and Gagarino) are located near

Ceramics, 2021

The work is devoted to the study of radiation damage and subsequent swelling processes of the sur... more The work is devoted to the study of radiation damage and subsequent swelling processes of the surface layer of Li2ZrO3 ceramics under irradiation with heavy Xe22+ ions, depending on the accumulation of the radiation dose. The samples under study were obtained using a mechanochemical synthesis method. The samples were irradiated with heavy Xe22+ ions with an energy of 230 MeV at irradiation fluences of 1011–1016 ion/cm2. The choice of ion types is due to the possibility of simulating the radiation damage accumulation processes as a result of the implantation of Xe22+ ions and subsequent atomic displacements. It was found that, at irradiation doses above 5 × 1014 ion/cm2, point defects accumulate, which leads to a disordering of the surface layer and a subsequent decrease in the strength and hardness of ceramics. At the same time, the main process influencing the decrease in resistance to radiation damage is the crystal structure swelling as a result of the accumulation of defects and...

ESR dosimetry of teeth from the victims of the JCO accident

No evidence for the TRI-effect in the gray and neutron emission so far. No evidence for the TRI-e... more No evidence for the TRI-effect in the gray and neutron emission so far. No evidence for the TRI-effect in the gray and neutron emission so far. Historical background (II)

7 Graduated School 0/ Engineering. Hiroshima University. Japan 'Center 0/ Medical Education. ... more 7 Graduated School 0/ Engineering. Hiroshima University. Japan 'Center 0/ Medical Education. Sapporo Medical University, Japan 'School 0/ Dentistry. Ohu University. Koriyama-shi. Japan 10 Low Level Radioactivity Laboratory. K-INET, Kanazawa University, Japan " Graduate School 0/ Biomedical Sciences, Hiroshima University. Japan The method of electron spin resonance (ESR) dosimetry was used to human tooth enamel to obtain individual absorbed doses of population of settlements in the vicinity of the Semipalatinsk Nuclear Test Site (SNTS), Kazakhstan. The distances between investigated settlements and Ground Zero (SNTS) are in the range 70 200 km from SNTS. Most of settlements (Dol on, Mostik, Bodene) are located near the central axis of radioactive fallout trace from the most contaminating surface nuclear test, which was conducted in 29, August 1949. The other settlements located close to radioactive fallout trace as a result of surface nuclear tests in 24, August 1956 (Us...

Lop Nor Influence investigation to population of Kazakhstan

Scientific Reports, 2021

To understand the radiation effects of the atomic bombing of Hiroshima and Nagasaki among the sur... more To understand the radiation effects of the atomic bombing of Hiroshima and Nagasaki among the survivors, radiation from neutron-induced radioisotopes in soil should be considered in addition to the initial radiation directly received from the bombs. 56Mn, which emits both β particles and γ-rays, is one of the dominant radioisotopes created in soil by neutrons from the bomb. Thus we investigated the biological effects of internal exposure to 56MnO2 particle in the lung of male Wistar rats comparing to the effects of external 60Co-γ irradiation. Absorbed doses of internal irradiation of lungs were between 25 and 65 mGy in 56MnO2-exposed animals, while the whole body doses were between 41 and 100 mGy. Animals were examined on days 3 and 61 after the exposure. There were no remarkable pathological changes related to 56MnO2 particle exposure. However, mRNA and protein expressions of aquaporin 5 increased significantly in the lung tissue on day 3 postexposure in 56MnO2 groups (by 1.6 and ...

Radiation and Environmental Biophysics, 2020

The experiment was performed in support of a Japanese initiative to investigate the biological ef... more The experiment was performed in support of a Japanese initiative to investigate the biological effects of irradiation from residual neutron-activated radioactivity that resulted from the A-bombing. Radionuclide 56Mn (T1/2 = 2.58 h) is one of the main neutron-activated emitters during the first hours after neutron activation of soil dust particles. In our previous studies (2016–2017) related to irradiation of male Wistar rats after dispersion of 56MnO2 powder, the internal doses in rats were found to be very inhomogeneous: distribution of doses among different organs ranged from 1.3 Gy in small intestine to less than 0.0015 Gy in some of the other organs. Internal doses in the lungs ranged from 0.03 to 0.1 Gy. The essential pathological changes were found in lung tissue of rats despite a low level of irradiation. In the present study, the dosimetry investigations were extended: internal doses in experimental mice and rats were estimated for various activity levels of dispersed neutro...

International Journal of Molecular Sciences, 2020

To investigate the biological effects of internal exposure of radioactive 56MnO2 powder, the majo... more To investigate the biological effects of internal exposure of radioactive 56MnO2 powder, the major radioisotope dust in the soil after atomic bomb explosions, on male reproductive function, the gene expression of the testes and the prostate was examined. Ten-week-old male Wistar rats were exposed to three doses of radioactive 56MnO2 powder (41–100 mGy in whole body doses), stable MnO2 powder, or external 60Co γ-rays (2 Gy). Animals were necropsied on Days 3 and 61 postexposure. The mRNA expressions of testicular marker protein genes and prostatic secretory protein genes were quantified by Q-RT-PCR. On Day 3 postexposure, the testicular gene expressions of steroidogenesis-related enzymes, Cyp17a1 and Hsd3b1, decreased in 56MnO2-exposed groups. Germ cell-specific Spag4 and Zpbp mRNA levels were also reduced. On postexposure Day 61, the Cyp11a1 gene expression became significantly reduced in the testes in the group exposed to the highest dose of 56MnO2, while another steroidogenesis-re...

Machine learning for determination of the native background EPR signal amplitude in the teeth enamel

Radiation Measurements, 2020

Abstract The measurement of teeth in vivo (i.e., in the mouth, without extraction) with EPR spect... more Abstract The measurement of teeth in vivo (i.e., in the mouth, without extraction) with EPR spectroscopy in the L-band would allow to screen large groups of population in an event of an acute radiation exposure and in routine epidemiological studies. The radiation dose is proportional to intensity of the radiation-induced signal amplitude determined after subtraction of both native and solar light induced signal amplitudes from the total signal amplitude measured in L-band. Therefore, to improve the dose assessments of in vivo tooth dosimetry a better accuracy of native background signal is necessary. In this work, we present a search for the optimal machine learning approach for predicting of intensity of the native signal amplitude. The study used the dataset from two institutes composed of 1800 EPR spectra which were recorded in the X-band at a large-scale examination of the population of the Central Russia and North Kazakhstan. To determine the relevance of 12 various features a preliminary statistical significance analysis was used. Predictive models for native signal amplitude determination were developed and trained using standard Python frameworks for machine learning and data processing. The employed algorithms included 8 most popular machine learning regressors. To tune the performance of each algorithm a common evaluation technique, namely cross-validation, was used. Finally, mean squared error and coefficient of determination were calculated for performance analysis of the employed models. Comparison among the performance of all established prediction models revealed that Random Forest and Gradient Boosting had most superior performance. Overall, the application of machine learning methods was shown to provide a minor (5–11% in terms of R2) but non negligible improvement to the accuracy of native signal amplitude prediction. Using the technique of adding synthetic noise variables, the most significant factor regarding the prediction was position of tooth in the quadrant.

E3S Web of Conferences, 2017

The tooth enamel electron paramagnetic resonance (EPR) dosimetry method was used to determine acc... more The tooth enamel electron paramagnetic resonance (EPR) dosimetry method was used to determine accidental doses of population of settlements in the vicinity of the Semipalatinsk Nuclear Test Site (SNTS), Kazakhstan. The influence of four explosions to the populations was included into this report. The distances between investigated settlements and Ground Zero (SNTS) are in the range of 70-200 km from SNTS. Most of settlements (Dolon, Mostik, Bodene, Cheremushki, Kanonerka) are located near the central axis of radioactive fallout trace from the most contaminating surface nuclear test, which was conducted in 29, August 1949. The other settlements located close to radioactive fallout trace result in a surface nuclear tests in 24, August 1956 (Ust-Kamenogorsk, Znamenka, Shemonaikha, Glubokoe, Tavriya, Gagarino), in 12 august 1953 (Sarzhal) and in 7, August 1962 (Akzhar, Kurchatov, Begen, Semenovka, Buras, Grachi). Tooth samples were extracted according to medical recommendations in a course of ordinary dental treatment.

Bulletin of the Karaganda University. "Physics" Series, 2019

Special dosimetry study of experimental rats exposure by sprayed 56 Mn powder was conducted durin... more Special dosimetry study of experimental rats exposure by sprayed 56 Mn powder was conducted during experiments in order to study internal irradiation effects. All experiments were performed in Kurchatov's reactor complex «Baikal-1» (Kurchatov city, East-Kazakhstan region) after neutron activation of stable Mn powder. This study was performed by group of scientists from Japan, Kazakhstan, and Russian Federation. The results of estimated doses in lungs alveolar epithelium of rats are shown in this paper. Absorbed dose on the «surface» of epitelium is equal to 160 Gy and absorbed dose in the «bottom» of epithelium for minimal thickness of epithelium cells is 8.9 Gy and for maximal thickness of epithelium cells equal to 0.4 Gy.

Radiation and Environmental Biophysics, 2017

The author would like to correct the Table in the original publication of the article. The correc... more The author would like to correct the Table in the original publication of the article. The correct table is given below: The online version of the original article can be found under

Radiation and Environmental Biophysics, 2017

to any additional radiation (control). On days 3, 14, and 60 after exposure, the animals were kil... more to any additional radiation (control). On days 3, 14, and 60 after exposure, the animals were killed and major organs were dissected and subjected to histopathological analysis. As described in more detail by an accompanying publication, the highest internal radiation dose was observed in the digestive system of the rats, followed by the lungs. It was found that the number of mitotic cells increased in the small intestine on day 3 after 56 Mn and 60 Co exposure, and this change persisted only in 56 Mn-exposed animals. Lung tissue was severely damaged only by exposure to 56 Mn, despite a rather low radiation dose (less than 0.1 Gy). These data suggest that internal exposure to 56 Mn has a significant biological impact on the lungs and small intestine.

EPR pilot study on the population of Stepnogorsk city living in the vicinity of a uranium processing plant

Radiation and Environmental Biophysics, 2014

The aim of this pilot study was to evaluate possible doses in teeth received by workers of a uran... more The aim of this pilot study was to evaluate possible doses in teeth received by workers of a uranium processing plant, in excess to the natural background dose. For this, the electron paramagnetic resonance dosimetry method was applied. Absorbed doses in teeth from the workers were compared with those measured in teeth from the Stepnogorsk city population and a control pool population from Astana city. The measured tooth samples were extracted according to medical indications. In total, 32 tooth enamel samples were analyzed, 5 from Astana city, Kazakhstan (control population), 21 from the residents of Stepnogorsk city (180 km from Astana city), and 6 from the workers of a uranium processing plant. The estimated doses in tooth enamel from the uranium processing plant workers were not significantly different to those measured in enamel from the control population. In teeth from the workers, the maximum dose in excess to background dose was 33 mGy. In two teeth from residents of Stepnogorsk city, however, somewhat larger doses were measured. The results of this pilot study encourage further investigations in an effort to receiving a final conclusion on the exposure situation of the uranium processing plant workers and the residents of Stepnogorsk city.

Feasibility of using 236U to reconstruct close-in fallout deposition from the Hiroshima atomic bomb

Science of The Total Environment, 2010

The first results on the feasibility of using (236)U to reconstruct the level and spatial distrib... more The first results on the feasibility of using (236)U to reconstruct the level and spatial distribution of close-in fallout deposition from the Hiroshima A-bomb are reported, coupled with the use of global fallout (137)Cs and (239+240)Pu. The results for global fallout (236)U in soil samples (0-30cm) from Ishikawa prefecture showed that the deposition density of (236)U from the global fallout can be accurately evaluated using AMS. All deposited (236)U, (137)Cs and (239+240)Pu appeared to have been recovered using 30-cm cores. It was also noted from the depth profiles for (236)U/(239+240)Pu and (236)U/(137)Cs ratios that the downward behavior of (236)U in the soil was apparently similar to that of (239+240)Pu, while the (137)Cs was liable to be retained in upper layers compared with (236)U and (239+240)Pu. The accumulated levels were 1.78×10(13)atomsm(-2) for (236)U, 4340Bqm(-2) for (137)Cs and 141Bqm(-2) for (239+240)Pu. The ratios of (236)U/(137)Cs and (236)U/(239+240)Pu were (4.10±0.12)×10(9) and (1.26±0.04)×10(11)atomsBq(-1), respectively. Results of (236)U, (137)Cs and (239+240)Pu measurements for the seven soil cores (0-30cm) from Hiroshima were discussed on the basis of ratios of (236)U/(137)Cs and (236)U/(239+240)Pu by comparing with those from the background area in Ishikawa, indicating that the global fallout dominates the current level of (236)U accumulation in soil in the Black-rain area around Hiroshima after the Hiroshima bomb, and the contribution of the close-in fallout (236)U produced by the Hiroshima A-bomb seems difficult to observe.

Radiation Measurements, 2007

For intercomparison of methods of dose determination using electron paramagnetic resonance (EPR) ... more For intercomparison of methods of dose determination using electron paramagnetic resonance (EPR) spectroscopy of tooth enamel, the same sets of enamel samples were analyzed in different laboratories using similar recording parameters. The sets of samples included calibration samples irradiated in known doses, test samples irradiated to doses unknown to the participants and accidental dose samples prepared from teeth of humans affected by radioactive fallout from nuclear tests in the Semipalatinsk Nuclear Test Site in Kazakhstan. The test samples were analyzed to determine the differences in the resulting doses using different spectrometers and different spectra processing methods. The accidental dose samples were analyzed in order to test the precision of doses determined by EPR spectroscopy and to obtain more accurate values by averaging the results from different laboratories.

Radiation Measurements, 2007

The method of electron paramagnetic resonance (EPR) dosimetry was used on human tooth enamel to o... more The method of electron paramagnetic resonance (EPR) dosimetry was used on human tooth enamel to obtain individual absorbed doses of residents of settlements in the vicinity of the Nuclear Test Site (SNTS) in Semipalatinsk region, Kazakhstan. Measured teeth were extracted according to medical indications. In total, 105 tooth enamel samples were analyzed, including eight tooth samples from control settlement Kokpekty, which is located 400 km to the Southeast from SNTS and was not subjected to any radioactive contamination. It was found that the excess doses obtained after subtraction of the contribution of natural background radiation ranged up to about 440 mGy for residents of Dolon, whose tooth enamel was formed before 1949, and do not exceed 100 mGy for younger residents. For residents of Mostik, excess doses do not exceed 100 mGy for all ages except in one resident, for whom an extremely high dose of 1250 mGy was registered. For Bodene settlement, excess doses higher than 100 mGy were obtained for two samples from the residents having enamel formed before 1949. An extremely high dose (2800 ± 400 mGy) was obtained for one resident of Semipalatinsk City. The average excess dose for Semipalatinsk samples with enamel formation before 1949 was determined close to the average excess dose for tooth enamel samples from Dolon village.

Radiation Measurements, 2011

The method of electron spin resonance (ESR) dosimetry was applied to human tooth enamel to obtain... more The method of electron spin resonance (ESR) dosimetry was applied to human tooth enamel to obtain estimates of individual absorbed dose for residents of Makanchi, Urdzhar and Taskesken settlements located near the KazakhstaneChinese border (about 400 km to the SoutheEast, from the Semipalatinsk Nuclear Test Site (SNTS) and about 1000 km from the Lop Nor Nuclear Weapons Test Base, China). Since the ground and atmospheric nuclear tests (1964e1981) at Lop Nor, the people residing in these settlements are believed to have been heavily exposed to radioactive fallout. Tooth samples had been extracted for medical reasons during the course of ordinary dental treatment. The village of Kokpekty, located 400 km to the Southeeast of the SNTS, was chosen as the control group since it has not been subjected to any radioactive contamination. The mean excess doses in tooth enamel obtained after subtraction of the contribution of natural background radiation do not exceed 62 AE 28 mGy, 64 AE 30 mGy, 49 AE 27 mGy and À19 AE 36 mGy for all ages of the residents of Makanchi, Urdzhar, Taskesken and the control village of Kokpekty, respectively.

ESR dosimetry study for the residents of Kazakhstan exposed to radioactive fallout on 24, August 1956

Radiation Measurements, 2011

The method of electron spin resonance (ESR) dosimetry has been applied to human tooth enamel in o... more The method of electron spin resonance (ESR) dosimetry has been applied to human tooth enamel in order to obtain individual absorbed doses from the population of settlements within the vicinity of the central axis of the radioactive fallout trace from the contaminating nuclear surface test of 24, August 1956. Most of the settlements (Glubokoe, Tavriya, and Gagarino) are located near