Surface irradiation of chicken eggs by nanosecond electron beam

The irradiation exposure experiments were carried out by means of the pulsed repetitive nanosecond accelerator URT-0.5 (electron energy of up to 500 keV, a pulse width of 50 ns, pulse repetition rate of up to 200pps). The determination of the distribution of the absorbed dose (AD) in the depth in the polyethylene was conducted by a gray wedge. The measurement of the electron beam AD on the surface of the shell (removed from the eggs) and under the shell, as well as beneath the absorber layer (polyethylene 80 microns thick) was also performed by the film dosimeter. Thermoluminescent dosimeters, TLD-500, were used to determine the distribution of the bremsstrahlung AD inside chicken eggs. These results lead to the conclusion that the irradiation of an electron beam with the AD level of 5 kGy is sufficient for complete disinfection on the surface of an egg. The AD inside of it will not exceed 8 cGy because of bremsstrahlung. © RAD Conference Proceedings. All rights reserved

Some Considerations on Sensitive Points of Modern Historical African Studies in Russia (Invitation to Discussion)

The article was submitted on 23.01.2023.В порядке дискуссии высказывается ряд соображений по проблемным точкам современных отечественных исследований по истории Африки. К ним относятся, в частности, необходимость более широкого использования самых различных типов и видов источников с особым вниманием к источникам африканского происхождения. Материалами Интернета следует пользоваться с большей осторожностью. Озабоченность автора вызывает некоторый перекос в исследованиях постколониальной проблематики в сторону изучения текстов о колониализме, предпочтительным кажется более глубокое исследование воздействия колониализма на африканские общества и его последствия. Представляется важным также более широкое овладение африканскими языками и использование их в полевых исследованиях. Вызывает озабоченность также невнимание к работам предыдущих поколений отечественных африканистов. Автор полагает, что учет коллегами высказанных соображений мог бы способствовать совершенствованию отечественных исследований по истории Африки.As an invitation to discussion, a number of considerations are made on the problematic points of modern Russian studies on African history of. These include the need for wider use of a variety of types of sources, with particular attention to sources of African origin. Internet materials should be used with greater caution. The author’s concern is caused by a certain bias in the research of postcolonial issues towards the study of texts about colonialism, a more in-depth study of the impact of colonialism on African societies and its consequences seems preferable. It is also important for historians to master African languages more widely and use them in field research. The lack of attention to the works of previous generations of Russian Africanists is also of concern. The author believes that taking into account the considerations expressed here by colleagues could contribute to the improvement of Russian studies on the history of Africa

An investigation of the disinfection effect in joint action of the nanosecond electron beam and plasma radiation

The subject of the investigation of the possible synergy sterilizing effect included the joint action by the nanosecond electron beam (NEB) and plasma radiation of nanosecond gas discharge of high pressure. Plasma radiation was carried out by the GVI-150 generator which loading involved a discharge camera. Pulse repetition rate of the generator operation was 37 pps, and distance from electrodes cutoff to processed samples ∼5 cm. The experiments on irradiation by the NEB were made on the pulse repetitive nanosecond accelerator URT-0.5 (electrons energy up to 500 keV, a pulse duration 50 ns, pulse repetition rate up to 200 pps). The time the vessel has been irradiated changed from 0 to 5 minutes; the absorbed dose (AD) of different batches changed from 0 to 5 kGy. The extensive data array on joint action of the NEB and plasma radiation for several types of widespread microorganism is received. Also, the synergetic effect of the NEB influence and plasma radiation on microorganisms such as Klebsiella is found. © Published under licence by IOP Publishing Ltd.This work was performed within a support of the Russian Science Foundation No. 16-16-04038)

Preparation of Iron Oxide Nanopowders by the Radiation-Chemical Method

Various magnetic nanopowders of iron oxide were obtained using the radiation-chemical method when irradiated with a nanosecond electron beam. The main physical and chemical characteristics of the prepared nanopowders were studied, such as structure, porosity, thermal resistance and magnetic properties. It was found that, by selecting precursors and the composition of the solution, it is possible to control not only the textural properties and yield of the obtained nanopowders (by changing the dose and dose rate intensity of the electron beam), but also to obtain crystalline or amorphous nanopowders, on which their magnetic properties depend. © 2021 Institute of Physics Publishing. All rights reserved.The reported study was funded by RFBR and GACR, project number 20-58-26002

Preparation of Silver Coated Oxide Nanomaterials and Study of Their Properties

Nanopowders of aluminum oxide silicon oxide and iron oxide with silver coating were produces by the radiation-chemical method. The dimensions of the nanoparticles were 50 to 80 nm, and the area can be changed from 2-3%, up to 40%. Was carried out the validation of antibacterial properties against E.coli and staphylococcus. Were estimated photocatalytic properties of nanopowders, which showed applications perspective as a photocatalytic agent. Cytotoxic properties were also investigated, which showed the relevance of the use of some the obtained composites for targeted drug delivery. © Journal of Physics: Conference Series 2021.The work was partially supported by the Russian Foundation for Basic Research and the Sverdlovsk Region as part of project No. 20-48-660019

Searching for Africa in Russia: The Fate of Apollon Davidson

The article was submitted on 01.06.2021.Статья посвящена анализу научного пути выдающегося отечественного африканиста, академика РАН Аполлона Давидсона. Ранее его личность привлекала внимание ученых прежде всего в связи с историей деятельности Центра африканских исследований Института всеобщей истории РАН, который был создан им в 1971 г. Проблема сюжета «Россия и Африка» в творчестве А. Б. Давидсона лишь фрагментарно затрагивалась в статьях, посвященных творчеству историка. Здесь впервые проанализирован вопрос об истоках интереса к Африке у А. Б. Давидсона, доказана тесная связь с атмосферой в сталинском Советском Союзе, в условиях которого происходило формирование личности историка. Проведенный анализ свидетельствует, что уход от проблематики, связанной с политической конъюнктурой, был для А. Б. Давидсона сознательным выбором, обусловленным стремлением уйти от создания пропагандистских сочинений в рамках господствовавшей идеологии. В статье выявлены ключевые сюжеты, которые привлекали внимание А. Б. Давидсона в рамках темы «Россия и Африка»: история формирования образа Африки в России, позиция России в англо-бурской войне 1899‒1902 гг., Коминтерн и Африка, основные направления советской политики в Африке. Особый интерес вызывает у А. Б. Давидсона сюжет, связанный с историей африканских путешествий Николая Гумилева и всплеском интереса к Африке среди российской интеллигенции эпохи Серебряного века. Публикация большинства исследований А. Б. Давидсона по данной проблематике стала возможна лишь в постсоветский период.This article is devoted to analysing the scholarly path of the outstanding Russian Africanist Apollon Davidson. His personality has already attracted scholarly attention, primarily in connection with the history of the Centre for African Studies of the Institute of Global History, which Davidson created in 1971. In this study, comprehensive analysis of the subject of Russia and Africa in Davidson’s work is conducted for the first time. Earlier research has only partially touched upon this theme. The main sources are Davidson’s works. The origins of Davidson’s interest in Africa are analyzed. This interest was closely connected with the atmosphere of Stalin’s Soviet Union, in the conditions of which the historian’s personality was formed. The analysis shows that avoiding problems related to the political situation was a conscious choice for Davidson, who sought to avoid having to write propaganda essays within the framework of the dominant ideology. The article identifies the key subjects that attracted Davidson’s attention: the formation of Africa’s image in Russia, the position of Russia in the Anglo-Boer War of 1899–1902, the Comintern and Africa, and the main aspects of Soviet foreign policy in Africa. It is shown that Davidson was especially interested in the African travels of Nikolai Gumilyov and the surge of interest in Africa among the Russian intelligentsia of the Silver Age. The publication of most of Davidson’s studies was possible only in the post-Soviet period

The use of nanosecond electron beam for the eggs surface disinfection in industrial poultry

Development of the technology bases of egg disinfection using surface irradiation is executed by the nanosecond electron beam. Experiments on shell eggs irradiation using the frequency nanosecond URT-0.5 accelerator were made. Determination of absorbed dose distributionwas executed. In case of irradiation by the electron beam with absorbed dose level 5 kGy, it is enough for the full disinfection of the surface and pores of egg shell. The absorbed dose in the egg at the expense of bremsstrahlung will not exceed 0.08 Gy which can't have essential action on protein. Irradiation of shell eggs batch in plastic package of 100 pieces pledged in an incubator together with an inspection lot of not irradiated egg was made. The percent of eggs deductibility and chickens survival of pilot and control batches were identical, indicating that there was no significant radio biological effect from irradiation of egg internal structures. The received chickens were grown up within the 5 weeks. It is established that the chickens who are grown up from the irradiated egg have no essential differences in development. © Published under licence by IOP Publishing Ltd.This work was performed within a support of the Russian Science No. 16-16-04038)

Magnetic properties and structure of TiO2-Mn (0.73 %) nanopowders: The effects of electron irradiation and vacuum annealing

Nanopowder TiO2-0.73 % Mn was synthesized by the sol-gel method. Thermal treatment of the samples was carried out in vacuum at a temperature of 500°C. Magnetic properties were studied in the temperature range from 2 to 850 K. The effects of electron irradiation and vacuum annealing on the EPR spectra and magnetic properties of TiO2-Mn powder are discussed. It was established that a part of manganese ions in the anatase crystal lattice interacts antiferromagnetically, which causes a decrease in magnetization as compared to the result of the calculation for non-interacting ions. Vacuum annealing leads to the formation of oxygen vacancies and, at the same time, to a noticeable increase in the ferromagnetic contribution to magnetization, especially, after preliminary electron irradiation. We assume that the ferromagnetic contribution to the magnetization appears either due to incomplete compensation of antiferromagnetically directed moments of manganese ions, or due to positive exchange interactions of Mn ions via defects in the TiO2 lattice. It is shown that the temperature of magnetic disordering in samples with a spontaneous magnetic moment exceeds 600°C. © 2019, Institute for Metals Superplasticity Problems of Russian Academy of Sciences. All rights reserved

Fragmentation of DNA in the male germ cells: impact on reproduction, the causes of origin and methods of diagnosis

The studying of DNA fragmentation in human sperm is necessary, because the DNA breaks, inherited from the paternal genome, could impact the embryo development. In this review the known mechanisms that cause DNA fragmentation in human sperm are considered. The mechanisms examined include: defects in chromatin remodeling during the process of spermiogenesis, apoptosis, oxygen radical-induced DNA damage. The different tests currently used for sperm DNA fragmentation analysis and the factors that determine the predictive value of sperm DNA fragmentation testing are also discussed.Необходимость изучения фрагментации ДНК сперматозоидов человека обусловлена возможным влиянием разрывов, унаследованных от отцовского генома, на эмбриональное развитие. В обзоре литературы рассмотрены известные механизмы, вызывающие фрагментацию ДНК в сперматозоидах человека. Данные механизмы включают в себя: дефекты ремоделинга хроматина в процессе спермиогенеза, апоптоз, повреждения ДНК свободными радикалами. Обсуждаются тесты, используемых в настоящее время для анализа фрагментации ДНК гамет