Radiation Load Research Articles

ВЛИЯНИЕ ЛЕКАРСТВЕННЫХ СРЕДСТВ, НОРМАЛИЗУЮЩИХ КРОВОСНАБЖЕНИЕ И ТРОФИКУ ОБЛУЧЕННЫХ ТКАНЕЙ, А ТАКЖЕ АНТИБИОТИКА ШИРОКОГО СПЕКТРА ДЕЙСТВИЯ НА ТЕЧЕНИЕ ТЯЖЕЛЫХ МЕСТНЫХ ЛУЧЕВЫХ ПОРАЖЕНИЙ У КРЫС

Purpose: To study in the experiment the therapeutic efficacy of drugs that normalize blood supply and trophism of irradiated tissues, as well as a complex broad-spectrum antibiotic, for the course of severe local radiation lesions to justify the clinical use of these drugs in this pathology. Material and methods: Wistar-Kyoto inbred rats were exposed to local X-rays in the ilio-lumbar region of the back at a dose of 110 Gy (tube voltage 30 kV, current 6.1 mA, Al filter 0.1 mm thick), at a dose rate of 20.1 Gy / min. Irradiation field area was 8.5 cm2. Radiation exposure caused the formation of long-term (up to 3.5–4 months) non-healing radiation ulcers of the skin without a critical radiation load on the underlying tissues. For the treatment of radiation lesions, an antibiotic was used – levotetrasulfin forte, as well as drugs that affect the blood supply and trophism of irradiated tissues – pentoxifylline and detralex. The drugs were administered daily both in isolation from each other and together during the period (from the 21st to the 42nd or from the 28th to the 48th day after irradiation), when the radiation ulcer formed and its gradual healing began. The everity of radiation skin lesions and the effects of therapy were assessed in dynamics by clinical manifestations and using planimetry. Results: It was found that the separate use of drugs in the treatment of severe local radiation lesions was not very effective. However, with the combined administration of drugs, a noticeable increase in the rate of healing of radiation ulcers was revealed. Thus, it was shown that with the joint administration of pentoxifylline (intraperitoneal, 50.0 mg / kg), detralex (75.0 mg / kg, per os) and levotetrasulfin forte (intraperitoneal, 0.1 ml / kg), the area of radiation ulcers in treated animals in the period from 98 to 126 days after irradiation was 26–80 % less compared to irradiated controls. Conclusion: The experiments show the possibility of successful use of a complex antibiotic in combination with drugs that improve blood supply and trophism of irradiated tissues, in the treatment of severe local radiation lesions.

Detailed insitu leaf energy budget permits the assessment of leaf aerodynamic resistance as a key to enhance non-evaporative cooling under drought.

The modulation of the leaf energy budget components to maintain optimal leaf temperature are fundamental aspects of plant functioning and survival. Better understanding these aspects becomes increasingly important under a drying and warming climate when cooling through evapotranspiration (E) is suppressed. Combining novel measurements and theoretical estimates, we obtained unusually comprehensive twig-scale leaf energy budgets under extreme field conditions in droughted (suppressed E) and non-droughted (enhanced E) plots of a semi-arid pine forest. Under the same high mid-summer radiative load, leaf cooling shifted from relying on nearly equal contributions of sensible (H) and latent (LE) energy fluxes in non-droughted trees to relying almost exclusively on H in droughted ones, with no change in leaf temperature. Relying on our detailed leaf energy budget, we could demonstrate that this is due to a 2× reduction in leaf aerodynamic resistance. This capability for LE-to-H shift in leaves of mature Aleppo pine trees under droughted field conditions without increasing leaf temperature is likely a critical factor in the resilience and relatively high productivity of this important Mediterranean tree species under drying conditions.

An anisotropic parameterization scheme for longwave irradiance and its impact on radiant load in urban outdoor settings

A robust representation of the radiative properties in complex urban settings is important for accurate estimations of radiant load. Here, we present a new parameterization scheme in the SOlar and LongWave Environmental Irradiance Geometry (SOLWEIG) model that partitions the upper hemisphere into 153 patches. Partitioning of the upper hemisphere enables determination if longwave irradiance originates from the sky, vegetation, sunlit building surfaces, or shaded building surfaces from each patch. Furthermore, a model for anisotropic sky longwave irradiance where emissivity increases with zenith angle is included. Comparisons between observations and simulations show high correlation, with R2 and RMSE for Tmrt of 0.94 and 4.6 °C, respectively, and R2 and RMSE for longwave radiation of 0.89 and 14.1 Wm−2, respectively. Simulations show that mean radiant temperature (Tmrt) can be up to 1.5 °C higher with an anisotropic sky compared to a uniform sky as an effect of higher radiant load on the vertical of a human when sky longwave irradiance increases with zenith angle. In comparisons of simulated Tmrt with the new parameterization and old parameterization schemes, previously overestimated Tmrt under trees (high sky obstruction, sky view factor (SVF) < 0.3) can be decreased by up to 3 °C from more realistic estimations using the patches. Moreover, Tmrt close to sunlit walls (SVF ~ 0.5) is increased by up to 2–3 °C from increased exposure to sunlit surfaces. Concluding, anisotropic sky longwave radiation and directionality of longwave radiation from different sources are important in estimations of Tmrt of humans in outdoor settings.

СРАВНИТЕЛЬНАЯ ХАРАКТЕРИСТИКА ПЛОТНОСТИ ОКОЛОПУЛЬПАРНОГО ДЕНТИНА В ПОСТОЯННЫХ ИНТАКТНЫХ ЗУБАХ У ЗДОРОВЫХ ДЕТЕЙ И У ДЕТЕЙ С НЕСОВЕРШЕННЫМ ОСТЕОГЕНЕЗОМ

The article presents the results of studying the degree of mineralization of the peripulpal dentin in healthy children and in children with osteogenesis imperfecta according to the data of cone beam computed tomography. In teeth with malformations of heavy tissue tissues, in particular with imperfect osteogenesis, pathological changes are noted in the special enamel and dentin involved in teeth and root canals. The study of the observed characteristics of the distribution of peripulpal dentin in dangerous intact teeth and teeth with malformations of hard dental tissues is of great interest.&#x0D; Subject. Of the study is the degree of mineralization of the peripulpal dentin in permanent intact teeth in healthy children and in children with osteogenesis imperfecta. &#x0D; Objectives. The degree of mineralization of periculpar dentin in children with osteogenesis imperfecta and in healthy peers in permanent intact teeth according to cone-beam computed tomography.&#x0D; Methodology. The study was performed at the Department of Pediatric Dentistry and at the Department of Radiation Diagnostics of the Moscow State Medical University named after A.I. Evdokimov in the Department of X-ray and Radiation Diagnostics of the CCCHLPHIS Clinic of the Moscow State Medical University named after A.I. Evdokimov. The study involved 22 patients aged 7 to 14 years.&#x0D; Results. In the group of children with imperfect osteogenesis in permanent molars with completed root formation, obliteration of the tooth cavity and wide root canals are noted. In the group of healthy children with permanent intact molars, no expansion of the tooth cavity and root canals was noted, no signs of root canal obliteration were detected. The average density of dentin in permanent molars in the group of healthy children is significantly higher than in children suffering from osteogenesis imperfecta.&#x0D; Conclusions. Cone-beam computed tomography is an objective method of visualizing the teeth of both jaws, which allows with minimal radiation load and high accuracy to determine the density of periculpar dentin in permanent teeth in children in one study. Pronounced violations of the mineralization of hard tissues of teeth in children with osteogenesis imperfecta and require further study as the child grows up at the stages of dental rehabilitation.

Solar wind H+ fluxes at 1 AU for solar cycles 23 and 24

The solar wind consists of electrons and ion species having kinetic energy ≲10 keVs. Ion stream is mainly composed of protons. Their flux magnitude is especially important for radiation hardness assurance scientists who qualify materials for future space missions. Materials irreversibly degrade as soon as are exposed to solar radiation. Hence, proton differential and integral flux spectra play a crucial role in properly estimating radiation loads deposited within satellite functional components. Up to now, the wind fluxes were read out, e.g., from figures made for specific periods of a solar cycle. This method is not effective and is a source of a flux, and further on, a fluence uncertainty. The objective of this work was to calculate and tabulate the solar wind differential and integral proton fluxes, which can be used further on to evaluatespace mission proton fluence spectra. Solar wind proton bulk velocity and number density from four space solar observatories (SOHO, ACE, WIND, and DSCOVR) were numerically processed to achieve that goal. Fluxes were tabulated and represented in calendar year periods.Now, the radiation hardness assurance community can quickly access, compute and compare SW proton fluxes from different energy ranges, calendar years, and satellite data sources. Proton fluxes presented here indicate magnitude variations along with the solar cycle period. A correlation between the number of sunspots and the proton average flux was found, i.e., the larger the number of spots, the larger the flux magnitude. More importantly, it was discovered that proton fluxes indicate huge variations in magnitude for a selected year based on different satellite data sources. For some years, the difference reaches 240%. This value is reported for the first time and shows that to have a complete picture of the SW proton stream population, one must compare data from all four satellites. Also, it is reported that satellites, for a given calendar year, record different ranges of proton velocity and number density values. This finding, even stronger, suggests a necessity of comparing SW data from as many solar observatories as possible. The spread in the proton flux magnitude (240%) has a direct implication for planning and executing satellite material on-ground radiation test campaigns. Not carefully choosing a proton flux may result in a false impression of how examined material would degrade under an interplanetary space radiation environment. In this article, recommendations for selecting proper proton spectra are given.

Viticulture adaptation to global warming: Modelling gas exchange, water status and leaf temperature to probe for practices manipulating water supply, canopy reflectance and radiation load

Associated with climate change, the frequency, duration, and intensity of heatwaves are increasing in most of the key wine regions worldwide. Depending on timing, intensity, and duration, heatwaves can impact grapevine yield and berry composition, with implications for wine quality. To overcome these negative effects, two types of mitigation practices have been proposed (i) to enhance transpiration and (ii) to reduce the radiation load on the canopy. Here we use a biophysical model to quantify the impact of these practices on canopy gas exchange, vine water status, and leaf temperature (Tl). Model validation was performed in a commercial vineyard. Modelled Tl from 14 to 43 °C, and transpiration, from 0.1 to 5.4 mm d−1, aligned around the identity line with measurements in field-grown vines; the RMSD was 2.6 ºC for temperature and 0.96 mm day−1 for transpiration. Trellis system and row orientation modulate Tl. A sprawling single wire trellis with an EW orientation maintained the canopy around 1ºC cooler than a Vertical Shoot Positioned canopy with NS for the same range of total fraction of soil available water (TFAW). Although irrigation before a heatwave is a recommended practice, maximum transpiration can be sustained even when TFAW is reduced, limiting the heat dampening effect of irrigation. Alternatively, canopy cooling can be achieved through Kaolin application, the installation of shade cloth placement, or canopy trimming. Shade cloth produced a greater cooling than Kaolin in all the simulated scenarios; however, Tl differences between them varied. Trimming reduced Tl from 2 ºC to almost 8 ºC compared to its non-trimmed counterpart. Our analysis presents new insights to design heat wave mitigation strategies and supports agronomically meaningful definitions of heat waves that include not only temperature, but also wind, VPD, and radiation load as these factors influence crop physiology under heat stress.

The Montreal Protocol and the fate of environmental plastic debris

Microplastics (MPs) are an emerging class of pollutants in air, soil and especially in all aquatic environments. Secondary MPs are generated in the environment during fragmentation of especially photo-oxidised plastic litter. Photo-oxidation is mediated primarily by solar UV radiation. The implementation of the Montreal Protocol and its Amendments, which have resulted in controlling the tropospheric UV-B (280–315 nm) radiation load, is therefore pertinent to the fate of environmental plastic debris. Due to the Montreal Protocol high amounts of solar UV-B radiation at the Earth’s surface have been avoided, retarding the oxidative fragmentation of plastic debris, leading to a slower generation and accumulation of MPs in the environment. Quantifying the impact of the Montreal Protocol in reducing the abundance of MPs in the environment, however, is complicated as the role of potential mechanical fragmentation of plastics under environmental mechanical stresses is poorly understood.

Bus Voltage Violations under Different Solar Radiation Profiles and Load Changes with Optimally Placed and Sized PV Systems

This study mainly discusses the implications of solar radiation profiles and changes in load with respect to base load conditions on the PV placement, size, voltage violations, and curtailment cost of PV generation in the network. The PV installation is optimized using yearly solar radiation profiles, low, medium, and high, corresponding to three different locations. The network in the study is represented as a multiphase, with provision for the installation of both single- and three-phase PV systems. For the different load changes in either one of the phases or all three phases, the optimal placement and size of PV inverters are discussed. It is indicated that with load increase in all three phases, for low solar radiation profiles, the placement and size of PVs remain non-uniform, while for medium and high solar radiation, the distribution becomes comparatively uniform throughout the network. However, with a load increase in one of the phases, for low solar radiation, optimal placement compensates with three-phase PV installation, while for medium/high solar, the corresponding load increase phase contributes to greater PV installation. The voltage rise is observed at both load-connected and non-load-connected buses. Such buses in the network are those that form the common junction with the branches connected to another set of buses having optimally placed PVs. The voltage violations are experienced at the feeder end buses with single-phase PV installation, not only in the phase having a connected load but also in one of the other phases.

Bioclimatic zoning as a prerequisite for architectural and structural design, urban and area-wide planning

Introduction. Factors of nature and climate were analyzed using bioclimatic criteria of environmental assessments made in within the framework of urban planning during warm seasons. Territories of republics, located in Central Asia and southern Kazakhstan, were considered as southern specimen areas; they have both plain and complex mountainous terrains, and their climatic and bioclimatic conditions make them similar to equatorial countries. The author chose a method for assessing bioclimatic indices; they take into account the response of the thermal status of a person to the environment, which is a rele­vant task of architectural and structural design and area-wide planning in southern countries with hot climates.&#x0D; Materials and methods. This research project is based on a comprehensive methodology for studying, analyzing and summarizing meteorological factors, provided by local meteorological stations, and reference data from the leading research institutes of hydrometeorology. These data are further processed by the software package to identify specific small and large microclimatic and bioclimatic differences between large areas. The methodology also determines the degree of comfort of a thermal state of a person in urban bioclimatology.&#x0D; Results. A new area of research was identified to study the response of the thermal state of a person to the environment: the bio-climatological assessment of environments. Bioclimatic zoning of republics in Central Asia and southern Kazakhstan was performed to classify the bioclimatic conditions in these environments according to their livability, taking into account values of meteorological indices during warm seasons. Bioclimatic differences between territories, cities, and excerpts from area development documents were identified for the purpose of bioclimatic zoning and division into districts. Maps of districts were designed to make bioclimatic forecasts of territories for the purpose of architectural and structural design, as well as urban planning.&#x0D; Conclusions. The research is relevant for territories and cities with hot climates. Methodological fundamentals of bioclimatic zoning in Central Asia and southern Kazakhstan, coupled with classified bio-meteorological indices, will serve as a prere­quisite for purposeful and rational use of territories in the region; they will allow evaluating its recreational potential and planning the construction of residential complexes, public and industrial buildings and structures that ensure maximum comfort and convenience at minimum costs. The classification of bioclimates is presented; it is based on thermal characteristics of climates as well as responses from the human thermoregulatory system during excessively hot summer periods. These responses are needed to characterize the thermal state of a person during periods of greatest heat stresses and radiation loads.

Динамика формирования поглощённых доз в крови лабораторных животных от альфа-излучающих радионуклидов с последовательными распадами

Since the beginning of the XXI century, active research has begun on the development of fundamentally new radiopharmaceutical drugs based on alpha-emitting maternal radionuclides for radionuclide therapy of micro-tumors and metastases. The main difficulty in assessing the absorbed doses of internal irradiation of such drugs is to take into account the radiation loads from all daughter radionuclides of sequential decay with alpha and beta transformations. The aim of the work is to develop a methodology for calculating the accumulated and total absorbed doses in the blood of laboratory animals from alpha-emitting radionuclides with successive decays within the framework of the compartment modeling method. To test the developed methodology and calculate the dosimetric characteristics, the free isotope Ac-225, injected into the blood as part of its chloride Ac-225Cl3, and the osteotropic preparation Ac-225-KHEDP (monokalium salt of hydroxyethylidendiphosphonic acid) labeled with it were selected. Quantitative data on the bio-distribution of Ac-225-KHEDP and Ac-225Cl3 in the body of intact mice were used to identify the necessary parameters. Calculations of the dosimetric characteristics of two Ac-225-labeled drugs in the blood of intact mice showed that the values of accumulated absorbed doses monotonically increase from the moment of drug administration, reaching their limit values equal to the total absorbed doses by about 300 hours. Alpha-emitting parent and daughter radionuclides make the main contribution to the values of total absorbed doses. The contribution of daughter beta-emitting radionuclides is significantly less, therefore, they can be ignored when preliminary estimates of the total absorbed doses are made. When using Ac-225-KHEDP, all radiation loads on the blood are approximately 2.5 times less compared to Ac-225Cl3, which is explained by the higher blood clearance value for Ac-225-KHEDP. The results obtained indicate the prospects for further studies of 225Ac-KHEDP and the possibility of its clinical application for the treatment of skeletal metastases.

Water Absorption of Cucumber Plants Based on Diurnal Variation in Plant Weight with Solar Radiation and Fruit Load

Water Absorption of Cucumber Plants Based on Diurnal Variation in Plant Weight with Solar Radiation and Fruit Load

MISTRAL campaign in support of W7-X long pulse operation

Following two initial campaigns [1], Stellarator Wendelstein 7-X (W7-X) has now completed the construction phase by installation of active cooling of all plasma facing components. The machine is presently commissioned for the next campaign (OP2) aiming at 1 GJ per pulse, e.g. 100 s at 10 MW, eventually aiming at 18 GJ, e.g. 1800 s at 10 MW. The key heating system is the Electron Cyclotron Resonance Heating (ECRH) system, consisting of 10 gyrotrons with power per gyrotron ranging from 0.6 MW up to 1.0 MW at 140 GHz. A phased upgrade of the installation is in progress with the addition of 2 gyrotrons and the development of 1.5 MW and 2.0 MW gyrotrons, such that at the end of the upgrade 4 gyrotrons will be available in each power class of 1.0, 1.5 and 2.0 MW [2]. The increased ECRH power, combined with O2 and X3 heating schemes at high densities, will lead to increased microwave stray radiation. This is non-absorbed microwave power that diffuses inside the vessel and is incident on all in-vessel components including vacuum windows and attached diagnostic systems. A fraction of the stray radiation is absorbed by resistive or dielectric losses of these components, leading to thermal loads that scale with stray radiation levels and pulse length. At W7-X a high power microwave stray radiation launch facility ’MISTRAL’ is available that is used to qualify invessel components for use at specified microwave surface power densities [Wm−2]. This paper reports on MISTRAL campaigns in 2020 2021 for testing of stray radiation loads during OP2 in W7-X, as well as on an EUROfusion program assessing stray radiation loads on ITER components. A dedicated, absolutely calibrated, caloric load was developed for the campaign to obtain measurement of stray radiation power levels as well as to conveniently expose samples. Amongst other we report on shielding concepts using metal enclosures combined with microwave absorbing coatings and dielectric heating of vacuum windows.

Расчёт фармакокинетических и дозиметрических характеристик Lu-177-ЭДТМФ – потенциального препарата для радионуклидной терапии костных метастазов

Phosphonic acids labeled with beta-emitting radionuclides are promising radiopharmaceutical drugs for palliative therapy of bone metastases. Currently, the possibility of using a new osteotropic compound N,N,N’,N’-ethylenediaminetetrakis (methylene phosphonic acid) with lutetium-177 (177Lu-EDTMP) is being studied. The aim of the work is to develop a compartment mathematical model of the kinetics of 177Lu labeled osteotropic radiopharmaceutical drugs in the body of laboratory animals and calculate their pharmacokinetic and dosimetric characteristics based on it. To assess the stability of 177Lu-EDTMP in vivo, the characteristics of the distribution of free lutetium in the form of 177LuCl3 were also studied. To identify the model parameters and calculate the characteristics of radiopharmaceutical drugs, quantitative data on the bio-distribution of 177Lu-EDTMP and 177LuCl3 in the body of intact Wistar rats were used. A compartment model of kinetics has been developed and two approaches to the identification of its transport constants have been proposed – through the residual functional and using approximation by monoexponential functions. According to pharmacokinetic modeling, it was found that 177Lu-EDTMP is deposited in bone tissues (up to 55% of the administered dose). The calculated value of the apparent volume of distribution of 177Lu-EDTMP is approximately 200 times greater than the volume of blood plasma, the values of biological half-lives from bone tissues are 10-20 times higher than from internal organs. The excretion of 177Lu-EDTMP from the body occurs mainly through renal clearance. Comparative modeling with 177LuCl3 revealed high resistance of 177Lu-EDTMP in vivo. The highest values of absorbed doses are formed in the skeleton and kidneys with minimal radiation load on other internal organs and blood. The results obtained indicate the prospects for further studies of 177Lu-EDTMP and the possibility of its clinical application for the treatment of skeletal metastases.

Towards the use of robotic systems at nuclear facilities

Abstract The article addresses the matter of the mobile robotic systems (MRS) application at nuclear industry and nuclear energy facilities. Three main types of tasks solved with the help of MRS in order to ensure safety and reduce the radiation load on personnel are described. The scope of application and general requirements for such MRS, typical technological operations, control modes and human-robot interaction are discussed. It is shown that highly specialized robots are mainly used and that their design doesn’t imply a prompt replacement of the payload and adaptation to various tasks. It is noted that most of the modern MRS designed to operate at radiation-hazardous facilities are still teleoperated. The necessity of creating multifunctional modular reconfigurable MRS of various standard-size groups for use at nuclear facilities and increasing the level of their autonomy is substantiated. Key words Mobile robotic system, UGV, nuclear facility, teleoperation, supervisory control. Acknowledgements This work was carried out within the framework of the state assignment of the Ministry of Education and Science of Russia No. 075-00913-21-00 dated December 25, 2020 «Development of proposals for improving the state scientific, technical and industrial policy and popularizing achievements in the field of robotics based on an analysis of trends in the development of robotics in Russia and abroad».

ON THE ISSUE OF LIVER BIOPSY IN PATIENTS WITH METABOLICALLY ASSOCIATED FATTY LIVER DISEASE

The aim of the work was to evaluate the possibility of replacing liver biopsy with other methods of examination in patients with metabolically associated fatty liver disease. All patients were examined according to a single diagnostic algorithm consisting of four stages: physical, laboratory, instrumental (using non-invasive bioimpedansometry, multiparametric ultrasound examination, dual-energy X-ray absorptiometry in the "Whole body" mode, computer and magnetic resonance imaging), histological (evaluation of liver micropreparations on the SAF scale). the patients were divided into three groups, taking into account the results of histological examination of biopsies on the SAF scale: group 1 – patients with hepatic steatosis without signs of inflammation, fibrosis (n = 56, 53.9%); group 2 – patients with steatohepatitis and clinically insignificant hepatic fibrosis F0-F1 (n = 30, 28.8%); group 3 – patients with steatohepatitis and clinically significant liver fibrosis F2-F3 (n = 16, 15.4%). the correlation of findings obtained by the histological examination of liver biopsies and the data of ultrasound quantitative liver steatometry is high – r = 0.95 (for liver steatosis S1), r = 0.84 (for liver steatosis S2), r = 0.91 (for liver steatosis S3); ultrasonic shear wave elastography – r = 0.84 (for clinically insignificant liver fibrosis F0-F1), r = 0.88 (for clinically significant liver fibrosis F2-F3). the data obtained using dual-energy X-ray absorptiometry in the "Whole Body" mode quantitatively reflect the state of the patient's metabolic status, they can be evaluated in dynamics due to low radiation load. Thus, the diagnostic complex consisting of assessing the level of hepatic transaminases, multiparametric ultrasound examination and dual-energy X-ray absorptiometry in the "Whole body" mode is optimal to examine the patients who have contraindications to liver biopsy or completely refuse to pass this study. in case of the patient's consent, absence of contraindications, as well as in the presence of a number of diffuse liver diseases, histological examination is recommended to identify and to assess in detail the dystrophic, inflammatory, sclerotic, regenerative processes.

Magnetite Nanoparticles as Solar Photo-Fenton Catalysts for the Degradation of the 5-Fluorouracil Cytostatic Drug.

Heterogeneous catalysts based on magnetite nanoparticles, Fe3O4, were prepared by the chemical coprecipitation method using iron (III) chloride as a salt precursor. The physicochemical properties of the nanoparticles were determined by different techniques and the efficiency was evaluated for the degradation of the cytostatic drug, 5-fluorouracil (5-FU), in aqueous solution by photo-Fenton process under simulated solar radiation. The most influential parameters, namely pH of the solution, catalyst load, H2O2 dosage, and use of radiation, were studied and optimized in the degradation process. The optimal conditions to achieve a 100% degradation of 5-FU (10 mg L-1) and a high mineralization degree (76%) were established at the acidic pH of 3.0, 100 mg L-1 of catalyst loading, and 58 mM of H2O2 under simulated solar radiation. The contribution of iron leaching to the catalyst deactivation, the role of the dissolved iron ions on homogenous reactions, and the stability of the catalyst were assessed during consecutive reaction cycles.

ВИЗУАЛИЗАЦИЯ ПАТОЛОГИИ ОРГАНОВ ГРУДНОЙ КЛЕТКИ У ДЕТЕЙ И ВОЗМОЖНОСТИ СНИЖЕНИЯ ЛУЧЕВОЙ НАГРУЗКИ

Introduction Possibilities of alternative imaging methods without the use of ionizing radiation Possibilities of optimizing the radiation load in diagnostic methods using ionizing radiation Features of the organization of work during the examination of children and anesthesiological support Conclusion

Small globes and pocket heat stress meters for WBGT and PHS evaluations. A critical analysis under controlled conditions

This paper is aimed at quantifying the effects of the well-known criticalities related to the use of small globes in the assessment of extreme hot thermal environments. Based on the experimental measurements carried out through a special apparatus able to reproduce a black enclosure under controlled conditions, the analysis has been focused on both screening (WBGT) and rational (PHS) assessment methods. Obtained results showed the underestimation of the WBGT values within 1 °C using small globes for measuring the WBGT index according to the Standard ISO 7243 and no relevant errors occur also in the presence of high radiative loads. These errors can be even eliminated if specific correction coefficients for the heat transfer by convection are used. On the other hand, pocket WBGT meters based upon small globes and psychrometric (shielded) sensors – instead of the wet wick – are affected by an unacceptable underestimation (by more than 10 °C) of the WBGT that is particularly enhanced at low air velocity and high radiative loads. Finally, the systematic underestimation of the mean radiant temperature measured through small globes can lead the allowable exposure times predicted by the PHS model to be underestimated by more than 5 h when a 38 mm table-tennis ball is used.

Hygienic problems of using information and computer technology devices by children

There was carried out the analysis of information and computer technologies (ICT), which are the main hygienically significant sources of non-ionizing electromagnetic radiation for children and adolescents. Early forecasts (before 2008) about the adverse impact of the ICT electromagnetic field on the health of children and adolescents, the fundamental scientific basis for forecasts and data on their feasibility to date are considered. According to state statistics, forecasts of an increase in morbidity due to EMF exposure to children and adolescents are likely to come true. For the period 1995-2019, 15-17 years children, a steady trend was identified for the gain in cerebral malignant neoplasms, diseases of the nervous system, blood, hematopoietic organs, and individual disorders involving the immune mechanism. The number of recorded malignant neoplasms of the brain in the adolescent contingent allows performing for the first time “case-control” analysis. Uncertainties in assessing the conditionality of the increase in the incidence in children under the influence of non-ionizing ICT electromagnetic radiation are associated with difficulties in determining personal doses. The limits of EMF exposure of the user’s head by a mobile device, which were developed in 1994, are now outdated and it is necessary to change the limits, as the devices and parameters of exposure to non-ionizing electromagnetic radiation of ICT have changed. It is necessary to confirm the reliability of the hygienic safety factor of EMF remote control in relation to children’s contingents in the conditions of modern and promising information and computer technologies, including taking into account possible synergy under the action of radio frequency EMF, optical screen radiation, sound effects and functional load. Obviously, today what is required is an integrated approach to ensuring the health of children “hygiene in the digital environment”. The article substantiates the foreign standards to affect the design and equipment for information and communication technologies of the educational environment in the Russian Federation, which is one of the important reasons for the deterioration of children’s health.

Maximizing the pedestrian radiative cooling benefit per street tree

Outdoor heat stress is a growing problem in cities during hot weather. City planners and designers require more pedestrian-centered approaches to understand sidewalk microclimates. Radiation loading, as quantified by mean radiant temperature (TMRT), is a key factor driving poor thermal comfort. Street trees provide shade and consequently reduce pedestrian TMRT. However, placement of trees to optimize the cooling they provide is not yet well understood. We apply the newly-developed TUF-Pedestrian model to quantify the impacts of sidewalk tree coverage on pedestrian TMRT during summer for a lowrise neighbourhood in a midlatitude city. TUF-Pedestrian captures the detailed spatio-temporal variation of direct shading and directional longwave radiation loading on pedestrians resulting from tree shade. We conduct 190 multi-day simulations to assess a full range of sidewalk street tree coverages for five high heat exposure locations across four street orientations. We identify street directions that exhibit the largest TMRT reductions during the hottest periods of the day as a result of tree planting. Importantly, planting a shade tree on a street where none currently exist provides approximately 1.5–2 times as much radiative cooling to pedestrians as planting the same tree on a street where most of the sidewalk already benefits from tree shade. Thus, a relatively equal distribution of trees among sun-exposed pedestrian routes and sidewalks within a block or neighbourhood avoids mutual shading and therefore optimizes outdoor radiative heat reduction per tree during warm conditions. Ultimately, street tree planting should be a place-based decision and account for additional environmental and socio-political factors.