External Exposure Research Articles

Numerical Simulation of the Performance of Self-Healing Concrete in Beam Elements

The formation of cracks in concrete structures occurs due to a multitude of causes ranging from shrinkage to external loading and environmental exposure. This phenomenon can significantly affect the lifecycle of concrete structures. Self-healing concrete (SHC) is considered a promoted innovation capable of overcoming this inevitable occurrence. In accordance with current SHC development processes, this paper utilizes the numerical simulation approach to test the performance of reinforced SHC beam specimens modeled using the commercial software ABAQUS 6.14 (Vélizy-Villacoublay, France). This paper aims to contribute to the scarce literature on SHC models by utilizing the overlooked dicyclopentadiene (DCPD) agent and ambiguous variability of crystalline admixtures. The SHC is introduced to the beam models at various depths and analyzed using load against displacement curves compared with a reference model of ordinary concrete. The effects of SHC on the mechanical properties of structural elements were determined. The results show a distinct improvement of the load-carrying capacity of SHC beams, indicating an efficient contribution of SHC in structural applications.

History of Diagnostic Radiology in Ghana

The history of Radiology in Ghana which began in 1951 has not been fully documented. The establishment of the Ghana College of Physicians and Surgeons, of which the Faculty of Radiology is a part, the West African College of Surgeons, as well as other institutions for radiography training, have played a major role in improving the Radiologist/Population-, Radiologist/Radiographer- and Radiographer/Population ratios in the country. Credence has also been given to a number of aims and objectives of the Faculty of Radiology of the Ghana College of Physicians and Surgeons such as a) The turning out of Radiologists for 9 out of the 16 regions of the country. b) A vast improvement in the quality and quantity of radiological services to the citizenry by the provision of modern radiological equipment, as well as increased manpower for the various diagnostic procedures. c) The establishment of subspecialties such as Interventional radiology, Neuroradiology and Paediatric radiology. The article seeks to highlight some of the major achievements and challenges in the delivery of radiological services to the citizenry of Ghana. Some of the challenges facing the specialty such as inadequate equipment in some public hospitals and the lack of maintenance of same are discussed. There is also inequitable distribution of radiologists across the country. Recommendations in the area of increased number of resident’s slots for postgraduate training by the Ministry of Health, as well as the reestablishment of external exposure for trainers to deepen their knowledge for the training of residents have been mentioned.

An interaction effect of external noise and exposure duration on the spatial contrast sensitivity function

It has been demonstrated that contrast sensitivity is sensitive to stimulus exposure duration. Here, we investigated how the duration effect on contrast sensitivity was modulated by the spatial frequency and intensity of external noise. Through a contrast detection task, the contrast sensitivity function under 10 spatial frequencies, three external noise, and two exposure duration conditions was measured. The temporal integration effect was defined by the difference in contrast sensitivity or the area under the log contrast sensitivity function between short and long exposure durations. We found that (1) the temporal integration effect was less pronounced in the zero-noise condition than in the low- or high-noise condition; (2) in the zero-noise condition, a stronger temporal integration effect was observed at high spatial frequencies; (3) in the high-noise condition, a stronger temporal integration effect was observed at low spatial frequencies; (4) the spatial-frequency-dependent transient or sustained mechanism is also sensitive to external noise level; and (5) perceptual template model analysis revealed that both decreased additive internal noise and an improved perceptual template accounted for the temporal integration effect, and these two factors were tuned to spatial frequency.

The Imprint of Exposome on the Development of Atopic Dermatitis across the Lifespan: A Narrative Review.

Atopic dermatitis (AD) is a chronic inflammatory skin condition that affects more than 200 million people worldwide, including up to 20% of children and 10% of the adult population. Although AD appears frequently in childhood and often continues into adulthood, about 1 in 4 adults develop the adult-onset disease. The prenatal period, early childhood, and adolescence are considered critical timepoints for the development of AD when the exposome results in long-lasting effects on the immune system. The exposome can be defined as the measure of all the exposures of an individual during their lifetime and how these exposures relate to well-being. While genetic factors could partially explain AD onset, multiple external environmental exposures (external exposome) in early life are implicated and are equally important for understanding AD manifestation. In this review, we describe the conceptual framework of the exposome and its relevance to AD from conception and across the lifespan. Through a spatiotemporal lens that focuses on the multi-level phenotyping of the environment, we highlight a framework that embraces the dynamic complex nature of exposome and recognizes the influence of additive and interactive environmental exposures. Moreover, we highlight the need to understand the developmental origins of AD from an age-related perspective when studying the effects of the exposome on AD, shifting the research paradigm away from the per se categorized exposome factors and beyond clinical contexts to explore the trajectory of age-related exposome risks and hence future preventive interventions.

A Review on Tetrabromobisphenol A: Human Biomonitoring, Toxicity, Detection and Treatment in the Environment.

Tetrabromobisphenol A (TBBPA) is a known endocrine disruptor employed in a range of consumer products and has been predominantly found in different environments through industrial processes and in human samples. In this review, we aimed to summarize published scientific evidence on human biomonitoring, toxic effects and mode of action of TBBPA in humans. Interestingly, an overview of various pretreatment methods, emerging detection methods, and treatment methods was elucidated. Studies on exposure routes in humans, a combination of detection methods, adsorbent-based treatments and degradation of TBBPA are in the preliminary phase and have several limitations. Therefore, in-depth studies on these subjects should be considered to enhance the accurate body load of non-invasive matrix, external exposure levels, optimal design of combined detection techniques, and degrading technology of TBBPA. Overall, this review will improve the scientific comprehension of TBBPA in humans as well as the environment, and the breakthrough for treating waste products containing TBBPA.

Using Machine Learning to Expedite the Screening of Environmental Factors Associated with the Risk of Spontaneous Preterm Birth: From Exposure Mixtures to Key Molecular Events

Spontaneous preterm birth (SPB) is affected by various environmental exposures. However, there is still an urgent need to efficiently integrate exposomic information to build its prediction model and unveil the potential toxic pathways. Here, we conducted a nested case-control study by recruiting 30 women with SPB delivery (cases) and 30 women without (controls) at their early pregnancy. We analyzed various biomarkers of external chemical exposure, lipidomics, and immunity, resulting in 1081 exposure features. A logistic regression model (LR) was used to screen potential risk factors, and four statistical learners were used to establish SPB prediction models. Overall, the serum lipid concentration in cases was higher than in controls, while this was not the case for chemical and immune biomarkers. Random forest (RF) and extreme gradient boosting (XGboost) models had a relatively higher prediction accuracy of > 90%. Glycerophospholipids (GP) were the most abundant lipidomic features screened by LR, RF, and XGboost models, followed by glycerolipids and sphingolipids, shown as well as by enrichment analysis. Moreover, FA(21:0) had the largest contribution to the prediction performance. Maternal exposure to various elements can contribute to SPB risk due to their interaction with GP metabolism. Therefore, it is promising to use exposomic data to predict SPB risk and screen key molecular events.

ФАКТОРЫ РИСКА ЗАБОЛЕВАЕМОСТИ РАКОМ ПИЩЕВОДА В КОГОРТЕ РАБОТНИКОВ ПРЕДПРИЯТИЯ АТОМНОЙ ПРОМЫШЛЕННОСТИ

Purpose: To assess the influence of non-radiation factors and occupational radiation exposure on the incidence risk of esophageal cancer in nuclear workers considering various histological types of the cancer. Material and methods: The study was designed as a retrospective analysis that considered data on the cohort of workers employed at reactors, radiochemical and plutonium production facilities of the Mayak Production Association (PA) who had been hired during 1948–1982. The total number of workers included in the cohort was 21645. Using the EPICURE software, the relative risk (RR) and excess relative risk of the esophageal cancer incidence per unit of the accumulated gamma dose from external exposure (ERR/Gy) were estimated based on the Poisson regression. Results: By 31.12.2018, 47 esophageal cancers were reported in members of the study cohort; the majority of these cancers were squamous cell carcinomas. The incidence risk of esophageal cancer was lower in females than in males and it increased with attained age. The increased risk of esophageal cancer (all cases) was associated with current smoking (RR=12.6, 95 % CI 4.21, 42.13), gastroesophageal reflux disease (GERD) (RR=3.96, 95 % CI 1.60, 8.48), excess body weight and obesity (RR=1.21, 95 % CI 1.13, 2.08). The significantly increased RR of squamous cell esophageal carcinoma was found in current smokers and workers had GERD. The significantly increased RR of esophageal adenocarcinoma was found in current and former smokers. The risk of esophageal cancer (all cases and squamous cell carcinomas) was higher in workers who abused alcohol but the RR estimates were not statistically significant. A significant linear association of the esophageal cancer risk with gamma dose from external exposure was found: ERR/Gy=1.28 (95 % CI 0.21, 4.11) for all cases and ERR/Gy=1.01 (95 % CI 0.01, 3.95) for squamous cell carcinoma; these estimates are the risks adjusted for sex, age, smoking, alcohol, GERD and body mass index. No effect of occupational radiation exposure on the esophageal adenocarcinoma risk was found. Conclusion: This study confirmed obtained earlier data on the impact of occupational external gamma exposure on the risk of esophageal cancer in Mayak PA workers. The estimates of ERR/Gy of external gamma-ray exposure were updated having made adjustments for the most important non-radiation factors.

HExpPredict: In Vivo Exposure Prediction of Human Blood Exposome Using a Random Forest Model and Its Application in Chemical Risk Prioritization.

Due to many substances in the human exposome, there is a dearth of exposure and toxicity information available to assess potential health risks. Quantification of all trace organics in the biological fluids seems impossible and costly, regardless of the high individual exposure variability. We hypothesized that the blood concentration () of organic pollutants could be predicted via their exposure and chemical properties. Developing a prediction model on the annotation of chemicals in human blood can provide new insight into the distribution and extent of exposures to a wide range of chemicals in humans. Our objective was to develop a machine learning (ML) model to predict blood concentrations () of chemicals and prioritize chemicals of health concern. We curated the of compounds mostly measured at population levels and developed an ML model for chemical predictions by considering chemical daily exposure (DE) and exposure pathway indicators (), half-lives (), and volume of distribution (). Three ML models, including random forest (RF), artificial neural network (ANN) and support vector regression (SVR) were compared. The toxicity potential or prioritization of each chemical was represented as a bioanalytical equivalency (BEQ) and its percentage (BEQ%) estimated based on the predicted and ToxCast bioactivity data. We also retrieved the top 25 most active chemicals in each assay to further observe changes in the BEQ% after the exclusion of the drugs and endogenous substances. We curated the of 216 compounds primarily measured at population levels. RF outperformed the ANN and SVF models with the root mean square error (RMSE) of 1.66 and , the mean absolute error (MAE) values of 1.28 and , the mean absolute percentage error (MAPE) of 0.29 and 0.23, and of 0.80 and 0.72 across test and testing sets. Subsequently, the human of 7,858 ToxCast chemicals were successfully predicted, ranging from to . The predicted were then combined with ToxCast in vitro bioassays to prioritize the ToxCast chemicals across 12 in vitro assays with important toxicological end points. It is interesting that we found the most active compounds to be food additives and pesticides rather than widely monitored environmental pollutants. We have shown that the accurate prediction of "internal exposure" from "external exposure" is possible, and this result can be quite useful in the risk prioritization. https://doi.org/10.1289/EHP11305.

Dependence of the Translocation Frequency in Blood Lymphocytes on the Dose and Age at the Onset of Exposure in Residents of the Techa Riverside Settlements

Evaluation of age effect on the frequency of radiation-induced translocations, registered using FISH in circulating T-lymphocytes in the long-term period after exposure, is both of theoretical and practical interest for the purposes of biodosimetry. The objective of our study was to analyze the dose dependence of the translocation frequency in the peripheral blood T-lymphocytes in donors of different age who were exposed in the Techa Riverside settlements (n = 197). In cytogenetic studies, whole chromosome painting probes were used to stain three pairs of chromosomes. A total of 104,721 genome equivalents (GE) were calculated and 2,540 translocations were found. For each donor, the individual absorbed doses in organs and tissues at the time of blood sampling were calculated using the Techa River Dosimetry System. In addition, doses to T-lymphocytes and their progenitors were calculated using the innovative modelling approach with due account of age related-dynamics of T-lymphocytes. The age dependence of the translocation frequency was associated particularly with these doses. The main sources of donor exposure were 89,90Sr, accumulating in bones and irradiating the bone marrow almost locally. To assess the parameters of the dose-effect relationship, linear regression model was used. After taking into account background values, the lowest frequency of translocations per 1000 GE per Gy was found in donors aged 0–5 years at the time of exposure (9.3 ± 1.3), which is statistically significantly lower than in children aged 6–18 years (15.3 ± 1.5), but not in adults (11.9 ± 2.9). The value for adults (18 years) was characterized by the maximum scatter, but was close to the values obtained in an international study of nuclear enterprise personnel after external exposure (11.6 ± 1.6). The values of the background translocation frequencies registered in various age groups correspond to the published data obtained in a joint international study on unexposed donors. We have also confirmed the absence of sex-effect on the frequency of translocations.

Оценка персонифицированной реакции гемопоэтических стволовых клеток на гамма-облучение с использованием гуманизированных мышей

Assessment of individual responses of cells, tissues and the whole body to radiation exposure is an important challenge for radiobiology and radiation safety. The study was aimed to develop the method for estimation of the human hematopietic stem cell (HSC) individual response in the humanized mouse model. The cord blood or peripheral blood HSCs were administered to the NOD SCID immunodeficient mice. The number of maturing HSCs (CD34+ cells) and mature CD45+ leukocytes was assesed after the acute gamma exposure to the doses of 0.5 Gy, 1 Gy, and 1.5 Gy, along with the HSC share among all CD45low/+ cells within three days (period of maximum mortality) and 14 days (period of active restoration) after exposure. The relationship between the indicato values and the exposure dose was calculated by regression analysis. There was exponential relationship between the human HSC survival rate in humanized mice and the dose on day three after exposure (R2 = 0.93; F = 211; p < 0.01), while the relationship between the number of HSCs and the dose on day 14 after exposure was linear (R2 = 0.65; F = 12.9; p = 0.01). The C14/3 coefficient calculated as a ratio of the HSC share among all human CD45low/+ cells on day 14 after exposure to the same parameter on day three after exposure was proposed as an indicator of HSC mortality and HSC number restoration. C14/3 negatively correlated with the exposure dose (R2 = 0.57; F = 13.3; p = 0.004), it was higher in radioresistant mice and the model of cysteamine-induced radioresistance in humanized mice. The model mice humanized using the peripheral blood HSCs can be used to assess individual HSC response to acute external gamma exposure based on C14/3 and the data on the HSC survival and restoration.

ДОЗИМЕТРИЧЕСКАЯ ХАРАКТЕРИСТИКА КОГОРТЫ ПЕРСОНАЛА СИБИРСКОГО ХИМИЧЕСКОГО КОМБИНАТА В ПЕРИОД 1950–2010 гг.

Purpose: To give a dosimetric characterization of the personnel of the Siberian Chemical Plant (SCP) subjected to prolonged technogenic occupational exposure to ionizing radiation (IR) in the period 1950–2010, as well as the cohort of the personnel of the SCP involved in working with uranium compounds. Material and methods: SCP is one of the largest and oldest complexes of nuclear industry enterprises in the world, having experience in continuous dosimetric monitoring of personnel for more than 60 years. The database of the regional medical-dosimetric register of employees of the SCP (RMDR) contains information about all employees of the SCP for the entire history of the enterprise, including personal data of medical, dosimetric and professional nature of 65.350 employees of the SCP, of which more than 32.000 people were exposed to chronic technogenic occupational radiation in the range of low doses. The archive of the medical documentation of the Seversk Biophysical Research Center contains 55.569 medical histories of the employees of the SCP, 29.800 outpatient records and 11.953 autopsy protocols. Results: Employees of the radiochemical, chemical-metallurgical, sublimate and separation industries of the SCP were subjected to combined (external and internal) irradiation, while the personnel of the reactor production were exposed exclusively to external irradiation. Auxiliary production workers were mainly exposed to non-radiation factors. Individual dosimetric control (IDC) of external exposure was carried out for all workers who were in the zone of exposure to external radiation sources. The average accumulated dose of external radiation for employees of the SCP was 28.3 mSv. IDC of internal irradiation was carried out for all workers employed at the production site, where the excess of the regulatory level of the concentration of radionuclides in the air of the working area was detected. The average value of the activity of radionuclides in the urine of SCP workers does not exceed 0.74 Bq. The life status has been clarified for 80.8 % of the employees of the SCP. About 3.500 employees of the agricultural complex have an IDC for internal irradiation from uranium based on the results of a biophysical examination. The life status is established for 75 % of employees of the uranium cohort. Conclusion: For the first time, a dosimetric characteristic of a cohort of 65.350 workers of the SCP (21 % women) who started work in the period 1950–2010 was given. The cohort of the staff of the SCP is suitable for conducting epidemiological studies in order to establish the risks associated with the impact on the human body of technogenic occupational exposure to IR.

Study on the 24Na specific activity induced by external neutron irradiation based on ICRP 110 computational phantoms

The dose caused by external exposure to neutrons can be evaluated by measuring the induced 24Na activity due to interaction of 23Na in human body with neutrons. To investigate the difference between male and female in the 24Na activity, the MCNP code is used to simulate the ICRP 110 adult male and female reference computational phantoms irradiated by 252Cf neutrons. The results show that the average absorbed dose of whole body caused by per unit neutron fluence for the female phantom is (5.22 ± 0.06)% - (6.84 ± 0.05)% higher than that for the male phantom. The 24Na specific activity of male tissues/organs is higher than that of female, except muscle tissues, bone, colon, kidney, red marrow, spleen, gallbladder, rectum and gonads. The highest intensity of 24Na characteristic gamma rays on the body surface occurred at Z = 125 cm on the back for the male phantom, while the highest gamma ray fluence for the female phantom is at Z = 116 cm, both of which are aligned with liver. When 1 Gy of 252Cf neutrons irradiate the ICRP110 phantoms, (1.51–2.44) × 105 and (3.70–5.97) × 104 24Na characteristic gamma rays can be recorded in 10 min by 3-inch NaI(Tl) detector and Φ 5 × 3 cm3 HPGe detector, respectively.

Two nucleotide sugar transporters are important for cell wall integrity and full virulence of Magnaporthe oryzae.

Cell wall polysaccharides play key roles in fungal development, virulence, and resistance to the plant immune system, and are synthesized from many nucleotide sugars in the endoplasmic reticulum (ER)-Golgi secretory system. Nucleotide sugar transporters (NSTs) are responsible for transporting cytosolic-derived nucleotide sugars to the ER lumen for processing, but their roles in plant-pathogenic fungi remain to be revealed. Here, we identified two important NSTs, NST1 and NST2, in the rice blast fungus Magnaporthe oryzae. Both NSTs were localized in the ER, which was consistent with a function in transporting nucleotide sugar for processing in the ER. Sugar transport property analysis suggested that NST1 is involved in transportation of mannose and glucose, while NST2 is only responsible for mannose transportation. Accordingly, deletion ofNSTs resulted in a significant decrease in corresponding soluble saccharides abundance and defect in sugar utilization. Moreover, bothNSTs played important roles in cell wall integrity, were involved in asexual development, and were required for full virulence. The NST mutants exhibited decreasing external glycoproteins and exposure of inner chitin, which resulted in activation of the host defence response. Altogether, our results revealed that two sugar transporters are required for fungal cell wall polysaccharides accumulation and full virulence of M.oryzae.

Optimization of sound insulation of flat panel photobioreactors for bioenergy facades

Flat panel photobioreactors consisting of different layers of glass panes, designed to allow heat and microalgae biomass production in a water layer by solar radiation at the facade of buildings (i.e. bioenergy facade), were acoustically examined and further developed for increased sound insulation against external noise exposure. The sound insulation was first examined by simulations on double-, triple- and four-skin bioreactor variants. Parameters such as the distance between panes, the number and types of layers, as well as the material and thickness of the glass panes, were varied. Especially the influence of decoupling layers and an airlift on the sound reduction index was evaluated. Based on the simulation results, a modular prototype was developed which could be converted into a double-, triple- or four-skin structure as required. The sound reduction of these was studied in an acoustic window laboratory experimentally. The highest measured weighted sound reduction index of 51 dB was obtained with a four-skin photobioreactor variant with four glass pane layers and a water layer. The weighted sound reduction indexes for alternative four-skin opaque prototype variants with a plasterboard layer were 2—3 dB lower. The double- and triple-skin variants achieved 43—47 dB. The use of XPS as insulation material in the outer air layers of the triple- and four-skin variants reduced the weighted sound reduction index by 2 dB. The airlift needed for turbulent mixing of the microalgae had no effect on the sound insulation but increased the average ambient noise level by up to 10 dB. With 51 dB, the four-shell photobioreactor prototype achieves sound insulation class 5 according to the german regulation VDI 2719 for windows and thus fulfills the function of a sound insulation element in the facade of buildings or in a soundproof wall.

Assessment of occupational radiation exposure of NORM scales residues from oil and gas production

Radiological hazards from external exposure of naturally occurring radioactive materials (NORM) scales residues, generated during the extraction process of oil and gas production in southern Algeria, are evaluated. The activity concentrations of 226Ra, 232Th, and 40K were measured using high-purity gamma-ray spectrometry (GeHP). Mean activity concentration of 226Ra, 232Th and 40K, found in scale samples are 4082 ± 41, 1060 ± 38 and 568 ± 36 Bq kg−1, respectively. Radiological hazard parameters, such as radium equivalent (Raeq), external and internal hazard indices (Hex, Hin), and gamma index (Iγ) are also evaluated. All hazard parameter values were greater than the permissible and recommended limits and the average annual effective dose value exceeded the dose constraint (0.3 mSv y−1). However, for occasionally exposed workers, the dose rate of 0.65 ± 0.02 mSv y−1 is lower than recommended limit of 1 mSv y−1 for public.

Radiation safety considerations for the use of radium-224-calciumcarbonate-microparticles in patients with peritoneal metastasis.

Two ongoing phase I studies are investigating the use of radium-224 adsorbed to calcium carbonate micro particles (224Ra-CaCO3-MP) to treat peritoneal metastasis originating from colorectal or ovarian cancer. The aim of this work was to study the level of radiation exposure from the patients to workers at the hospital, carers and members of the public. Six patients from the phase 1 trial in patients with colorectal cancer were included in this study. Two days after cytoreductive surgery, they were injected with 7 MBq of 224Ra-CaCO3-MP. At approximately 3, 24 and 120 h after injection, the patients underwent measurements with an ionization chamber and a scintillator-based iodide detector, and whole body gamma camera imaging. The patient was modelled as a planar source to calculate dose rate as a function of distance. Scenarios varying in duration and distance from the patient were created to estimate the potential effective doses from external exposure. Urine and blood samples were collected at approximately 3, 6, 24, 48 and 120 h after injection of 224Ra-CaCO3-MP, to estimate the activity concentration of 224Ra and 212Pb. The patients' median effective whole-body half-life of 224Ra-CaCO3-MP ranged from 2.6 to 3.5 days, with a mean value of 3.0 days. In the scenarios with exposure at the hospital (first 8 days), sporadic patient contact resulted in a range of 3.9-6.8 μSv per patient, and daily contact resulted in 4.3-31.3 μSv depending on the scenario. After discharge from the hospital, at day 8, the highest effective dose was received by those with close daily contact; 18.7-83.0 μSv. The highest activity concentrations of 224Ra and 212Pb in urine and blood were found within 6 h, with maximum values of 70 Bq/g for 224Ra and 628 Bq/g for 212Pb. The number of patients treated with 224Ra-CaCO3-MP that a single hospital worker - involved in extensive care - can receive per year, before effective doses of 6 mSv from external exposure is exceeded, is in the order of 200-400. Members of the public and family members are expected to receive well below 0.25 mSv, and therefore, no restrictions to reduce external exposure should be required.

Monitoring the Environmental Radiation Levels for Some Regions in Iraq

The absorbed dose rates in air have been monitored in 23 different urban areas in Iraq using TLD dosimeter for the period 1992-1994 and in 2011-2012, with no significant differences observed. The risk of cancer incidence (morbidity) and mortality to the individuals related to external exposure to ambient gamma radiation is evaluated in this study using the linear, no-threshold (LNT) dose-response model. The risk estimations include delayed radiation effects (cancer morbidity, mortality and hereditary genetic damages). The mean effective dose equivalent to the individuals of 0.48 mSv/y is found to be less than the recommended dose limit to the public established by the International Atomic Energy Agency of 1 mSv/y. However, the findings of this study report that about 0.24% of the respective population are expected to be diagnosed with radiation-induced cancer over there lifetime. The lifetime fatal cancer probability (mortality) is estimated to be occurs at a rate of 0.18%. The risk of developing fatal stomach cancer is found to be occurs at a largest extent in comparison with other exposed body organs and tissues. Other consequences of radiation injury such as genetic effects transmitted to succeeding generations are expected to occur at a rate of 0.03% in the offspring of the respective population as a result of changes transmitted via the genetic mechanisms due to irradiation of gonads

СРАВНИТЕЛЬНАЯ ОЦЕНКА ПОГЛОЩЁННЫХ ДОЗ ПРОИЗВОДСТВЕННОГО И ДИАГНОСТИЧЕСКОГО ОБЛУЧЕНИЯ У ПАЦИЕНТОВ, ОБСЛЕДОВАННЫХ МЕТОДОМ КОМПЬЮТЕРНОЙ ТОМОГРАФИИ

A comparative assessment of the absorbed doses resulted from computed tomography (CT) examinations, and the dose resulted from occupational external gamma exposure of the “Mayak” workers was carried out. The patients’ diagnostic radiation dose was reconstructed using Monte-Carlo simulation on a population of 58 virtual adult phantoms across 13 CT protocol categories. Archival records of CT examinations of patients were used for the dose reconstruction. Information on technical parameters of scanning was extracted from DICOM files. The study sample has been linked to the Mayak worker register database to identify persons who had professional contact with ionizing radiation. Annual occupational dose records for the Mayak workers were obtained from the Dose-2013 dosimetry system. In this study, information on 212 patients was collected from 303 records. Among them, 42 Mayak employees were identified, including 24 persons who had non-zero dose of external gamma radiation, and 16 persons with internal alpha radiation dose due to occupational intake of 239Pu. Individual doses absorbed in the organs resulted from exposure to computed tomography and occupational activities has been compared. The results showed significant variability of the absorbed organ dose depending on the area of CT examination. The brain and lens were subjected to the highest radiation exposure during head CT. The average absorbed dose in brain was 24.5 mGy per single examination (the maximum brain dose accumulated over the entire study period was 82.3 mGy), and 27.7 mGy for the lens of the eye (the maximum lens dose reached 92.9 mGy). Relevant comparison of the absorbed dose of diagnostic and occupational exposure, accumulated during one year, has been performed. The average estimate of cumulative radiation dose absorbed in the organs during computed tomography was an order of magnitude lower than the one from occupational external gamma exposure of Mayak personnel, except brain dose. Annual CT dose equivalent of external gamma radiation was 2.82.

Development of physiologically based toxicokinetic models for 3-monochloropropane-1,2-diol and glycidol.

3-Monochloropropane-1,2-diol (3-MCPD), glycidol, together with their fatty acid esters are commonly presented in various food and have shown carcinogenicity in various laboratory animals. Public health risk assessment of 3-MPCD and glycidol exposure relies on quantitative tools that represent their in vivo toxicokinetics. In order to better understand the absorption, distribution, metabolism, and excretion profiles of 3-MCPD and glycidol in male rats, a physiologically based pharmacokinetic (PBTK) model was developed. The model's predictive power was evaluated by comparing in silico simulations to in vivo time course data obtained from experimental studies. Results indicate that our PBTK model successfully captured the toxicokinetics of both free chemicals in key organs, and their metabolites in accessible biological fluids. With the validated PBTK model, we then gave an animal-free example on how to extrapolate the toxicological knowledge acquired from a single gavage to a realistic dietary intake scenario. Three biomarkers, free compound in serum, urinary metabolite DHPMA, and glycidol-hemoglobin adduct (diHOPrVal) were selected for in silico simulation following constant dietary intakes, and their internal levels were correlated with proposed external daily exposure via reverse dosimetry approaches. Taken together, our model provides a computational approach for extrapolating animal toxicokinetic experiments to biomonitoring measurement and risk assessment.

Development of active heat-protective materials for information-measuring devices and systems experiencing thermal loads in emergency situations

The article deals with the problem of creating a t-protective coating for information-measuring devices and systems for various purposes exposed to external high-temperature exposure in emergency situations related to fire. As a solution to the problem, it is proposed to use thermal-protective materials containing active additives that provide a thermal-protective effect that promotes the refraction of heat flows aimed at heating the protected object. The heat-shielding effect is provided by an endothermic reaction that occurs in the material when the decomposition temperature of the selected component is reached. It should be noted that the temperature at which the reaction with heat absorption should occur should be lower than the temperature of the lesion of the protected object. In this case, the heat flows passing through the layer of heat-shielding material will be refracted, since heat will be spent on the decomposition of the endothermic filler. The heating of the material will be carried out due to the matrix of the material and decomposition products. Based on the tasks that require the use of a heat-protective material, the amount of endothermic filler is determined. Accordingly, with an increase in the time interval during which it is necessary to eliminate the fire, the content of endothermic filler also increases. The use of thermal-protective material is relevant for emergency flight data recorders, since in the event of a plane crash, a fire is likely to occur, which can lead to the loss of information necessary to determine the causes of an emergency.