Matrix model of inhomogeneous medium with circular birefringence in single scattering case

The paper is devoted to the analysis of light scattering by inhomogeneous circular birefringent media in a single scattering case. The object under investigation is a circular birefringent crystalline slab with surface inhomogeneity. For the analysis, we derive the Mueller matrix model for this media and use Cloude’s coherency matrix method. Sample calculations are given for quartz SiO₂ and paratellurite TeO₂

Light depolarization by inhomogeneous linear birefringent media

The purpose of the article is to provide rigorous analysis of light depolarization by inhomogeneous linear birefringent media in single scattering case. The object under investigation is a lossless anisotropic crystalline slab with surface inhomogeneity. For the analysis we use the Mueller matrix model of such class of media derived in [1], Cloude’s coherency matrix method and known single value depolarization metrics. Sample calculations are given for calcite CaCO₃, paratellurite TeO₂ and lithium niobate LiNbO₃

Interaction of low-energy protons with aluminum surface

The article presents the results of researches on the protons interaction with energy of 260 eV with a surface of aluminum foil at the temperature of 300 °C, ion current density of ~ 1.5 mA/cm² with an exposure of 11 hours. The surface is covered with bubbles and microcracks. There is a phenomenon of surface blistering. The substantial cleaning of the surface from oxides occurs due to sputtering of the surface, as well as because of their repair in hydrogen plasma. The hydrogen content substantially increases at the depth of the sample after irradiation of aluminum with protons. The sputtering plasma-chemical reactor materials is observed.Приведено результати досліджень взаємодії протонів з енергією 260 еВ з поверхнею алюмінієвої фольги при температурі 300 °С, щільності іонного струму ~ 1,5 мА/см² з експозицією 11 годин. Поверхня алюмінію значно змінюється після процесу опромінення, покривається бульбашками та мікрократерами. Cпостерігається явище поверхневого блістерінгу. Після опромінення алюмінію протонами істотно збільшується вміст водню поблизу поверхні зразка, вміст якого плавно зменшується за глибиною.Приведены результаты исследований взаимодействия протонов с энергией 260 эВ с поверхностью алюминиевой фольги при температуре 300 °С и плотности ионного тока ~ 1,5 мА/см² с экспозицией 11 часов. Поверхность алюминия значительно меняется после процесса облучения, покрывается пузырьками и микрократерами. Наблюдается явление поверхностного блистеринга. После облучения алюминия протонами существенно увеличивается содержание водорода вблизи поверхности образца, содержание которого плавно уменьшается по глубине

Features of the low energy protons interaction with molibden surface

The surface of molybdenum changes significantly after the proton irradiation process. The sputtering of the surface leads to a substantial cleaning of oxides. It is also possible to reduce oxides in a hydrogen plasma. The surface of molybdenum becomes more uneven with the manifestation of the fine structure after treatment. Molybdenum is sputtering at the rate ~ 0.1 µm/hour at the temperature of 300 °C and an ion current density ~ 1.5 mA/cm². The hydrogen content near the surface of molybdenum practically does not increase after irradiation with protons. The content of hydrogen in molybdenum does not change in depth, it is constant before and after irradiation. Molecular hydrogen is not observed in the both samples. The masses numbers of metal atoms is observed, which are part of the stainless steel (12X18N10T) from which the substrate holder is made.Поверхня молібдену значно змінюється після процесу опромінення. Відбувається істотне очищення поверхні від оксидів через розпилення поверхні. Можливе також відновлення оксидів у водневій плазмі. Поверхня молібдену після обробки стає більш нерівною з проявом дрібної структури. Відбувається розпорошення молібдену зі швидкістю ~ 0,1 мкм/год при температурі 300 °C і щільності іонного струму ~ 1,5 мА/см². Вміст водню поблизу поверхні зразка після опромінення молібдену протонами практично не збільшується. Вміст водню в молібдені за глибиною не змінюється, а є постійним як до опромінення, так і після. Молекулярний водень не спостерігається в обох зразках. Розділяються 7 ізотопів Мо і стільки ж його оксидів. На поверхні Мо після обробки спостерігається ряд мас атомів, які належать матеріалу утримувача підкладки з нержавіючої сталі (12Х18Н10Т) (ізотопи Cr, Fe, Ni, Ti, Mn і ін.). Спостерігаються також ізотопи інших домішок, які можуть перерозпилятися з тримача підкладки і кремнію, яким прикривається необроблювана ділянка зразка.Поверхность молибдена значительно изменяется после процесса облучения протонами. Происходит существенная очистка поверхности от оксидов из-за распыления поверхности. Возможно также восстановление оксидов в водородной плазме. Поверхность молибдена после обработки становится более неровной с проявлением мелкой структуры. Происходит распыление молибдена со скоростью ~ 0,1 мкм/ч при температуре 300 °C и плотности ионного тока ~ 1,5 мА/см². Cодержание водорода вблизи поверхности образца после облучения молибдена протонами практически не увеличивается. Содержание водорода в молибдене по глубине не меняется, а является постоянным как до облучения, так и после. Молекулярный водород не наблюдается в обоих образцах. Разделяются 7 изотопов Мо и столько же его оксидов. На поверхности Мо после обработки наблюдается ряд масс атомов, принадлежащих материалу держателя подложки из нержавеющей стали (12Х18Н10Т) (изотопы Cr, Fe, Ni, Ti, Mn и др.). Наблюдаются также изотопы других примесей, которые могут перераспыляться с держателя подложки и кремния, которым прикрывается необрабатываемый участок образца

SARS-CoV-2 will continue to circulate in the human population: an opinion from the point of view of the virus-host relationship

At the population level, the virus-host relationship is not set up to end with the complete elimination of either or both. Pathogen-resistant individuals will always remain in the host population. In turn, the virus can never completely eliminate the host population, because evolutionarily such an event is a dead end for the virus as an obligate intracellular parasite. A certain existential balance exists in the virus-host relationship. Against this backdrop, viral epidemics and pandemics only become manifest and egregious to human beings when tens and hundreds of thousands of people die and the question emerges what caused the high mortality peaks on the death chart. The answer seems clear; the emerging strain of the virus is new to the host population, and new mutations of the virus and natural selection will lead to a survival of only genetically resistant individuals in a host population. The dangers inherent to a novel virus are due to new features generally inthe molecular structure of proteins, which enable the virus to infect the cells of the host organism more intensively, dramatically challenging host immunity, and thus be transmitted more readily in the host population. In this article, we will concentrate on the facts currently available about severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), which has caused COVID-19 (coronavirus disease 2019) pandemic and try to predict its development and consequences based on the virus-host relationship. In fact, only two scenarios will occur simultaneously in the very near future: people who are genetically resistant to the virus will get sick, recover, and develop immunity, while people who are sensitive to the virus will need drugs and vaccines, which will have to be researched and developed if they are to recover. If the pandemic does not stop, in a few decades it is anticipated that SARS-CoV-2 will become as safe as the four non-severe acute respiratory syndrome human coronaviruses (HCoV-NL63, HCoV-HKU1, HCoV-OC43, and HCoV-229E) currently circulating but causing low mortality in the human population. © 2020, Springer Nature Switzerland AG

SARS-CoV-2 will continue to circulate in the human population: no worries with state-of-the-art research and dependably useful results

This short article provides additional justification for our understanding of the virus–host relationship in the population. Some new data are presented concerning viral structure/behavior and a critical assessment on the possibilities of using new approaches for the treatment of patients with COVID-19. © 2020, Springer Nature Switzerland AG

SARS-CoV-2 will constantly sweep its tracks: a vaccine containing CpG motifs in ‘lasso’ for the multi-faced virus

During the current COVID-19 pandemic, the global ratio between the dead and the survivors is approximately 1 to 10, which has put humanity on high alert and provided strong motivation for the intensive search for vaccines and drugs. It is already clear that if we follow the most likely scenario, which is similar to that used to create seasonal influenza vaccines, then we will need to develop improved vaccine formulas every year to control the spread of the new, highly mutable coronavirus SARS-CoV-2. In this article, using well-known RNA viruses (HIV, influenza viruses, HCV) as examples, we consider the main successes and failures in creating primarily highly effective vaccines. The experience accumulated dealing with the biology of zoonotic RNA viruses suggests that the fight against COVID-19 will be difficult and lengthy. The most effective vaccines against SARS-CoV-2 will be those able to form highly effective memory cells for both humoral (memory B cells) and cellular (cross-reactive antiviral memory T cells) immunity. Unfortunately, RNA viruses constantly sweep their tracks and perhaps one of the most promising solutions in the fight against the COVID-19 pandemic is the creation of 'universal' vaccines based on conservative SARS-CoV-2 genome sequences (antigen-presenting) and unmethylated CpG dinucleotides (adjuvant) in the composition of the phosphorothioate backbone of single-stranded DNA oligonucleotides (ODN), which can be effective for long periods of use. Here, we propose a SARS-CoV-2 vaccine based on a lasso-like phosphorothioate oligonucleotide construction containing CpG motifs and the antigen-presenting unique ACG-containing genome sequence of SARS-CoV-2. We found that CpG dinucleotides are the most rare dinucleotides in the genomes of SARS-CoV-2 and other known human coronaviruses, and hypothesized that their higher frequency could be responsible for the unwanted increased lethality to the host, causing a ‘cytokine storm’ in people who overexpress cytokines through the activation of specific Toll-like receptors in a manner similar to TLR9-CpG ODN interactions. Interestingly, the virus strains sequenced in China (Wuhan) in February 2020 contained on average one CpG dinucleotide more in their genome than the later strains from the USA (New York) sequenced in May 2020. Obviously, during the first steps of the microevolution of SARS-CoV-2 in the human population, natural selection tends to select viral genomes containing fewer CpG motifs that do not trigger a strong innate immune response, so the infected person has moderate symptoms and spreads SARS-CoV-2 more readily. However, in our opinion, unmethylated CpG dinucleotides are also capable of preparing the host immune system for the coronavirus infection and should be present in SARS-CoV-2 vaccines as strong adjuvants. © 2020, Springer Nature Switzerland AG

A short history of insecticides

This review contains a brief history of the use of insecticides. The peculiarities, main advantages, and disadvantages of some modern insecticides are described. The names of the discoverers of some of the most popular insecticide preparations on the world market, are listed. The tendencies to find new insecticides to control the quantity of phytophagous insects are discussed. Special attention is paid to the perspective of creating preparations based on nucleic acids, in particular DNA insecticides. The use of insect-specific, short single-stranded DNA fragments as DNA insecticides, is paving the way in the field of “intellectual” insecticides that “think” before they act. It is worth noting, though, that in the near future, the quantity of produced insecticides will increase due to the challenges associated with food production for a rapidly growing population. It is concluded, that an agreeable interaction of scientists and manufacturers of insecticides should lead to the selection of the most optimal solutions for insect pest control, which would be safe, affordable, and effective at the same time

Рeculiarities of interaction of low-energy protons with tungsten surface

The results of investigations of the interaction of protons with energy of 250…260 eV with the surface of tungsten foil are presented. Sputtering of tungsten occurs at a rate of ~ 0.5 μm/h at a temperature of 300°C and an ion current density of 1.5 mA/cm² . The surface of tungsten significantly changes after the irradiation process. The substantial surface cleaning occurs from oxides due to surface sputtering, and also because of their reduction in hydrogen plasma. The hydrogen content increases near the surface of the tungsten sample after irradiation with protons. The hydrogen content decreases in depth in tungsten.Наведено результати досліджень взаємодії протонів з енергією 250…260 еВ з поверхнею вольфрамової фольги. Відбувається розпорошення вольфраму зі швидкістю ~ 0,5 мкм/год при температурі 300°С і щільності іонного струму ~ 1,5 мА/см² . Поверхня вольфраму значно змінюється після процесу опромінення. Відбувається істотне очищення поверхні від оксидів через розпорошення поверхні, а також із-за їх відновлення у водневій плазмі. Після опромінення вольфраму протонами істотно збільшується вміст водню поблизу поверхні зразка. Вміст водню у вольфрамі повільно зменшується по глибині.Приведены результаты исследований взаимодействия протонов с энергией 250…260 эВ с поверхностью вольфрамовой фольги. Происходит распыление вольфрама со скоростью ~ 0,5 мкм/ч при температуре 300°С и плотности ионного тока ~ 1,5 мА/см² . Поверхность вольфрама значительно изменяется после процесса облучения. Происходит существенная очистка поверхности от оксидов из-за распыления поверхности, а также из-за их восстановления в водородной плазме. После облучения вольфрама протонами существенно увеличивается содержание водорода вблизи поверхности образца. Содержание водорода в вольфраме плавно уменьшается по глубине

Insecticidal activity of three 10–12 nucleotides long antisense sequences from 5.8S ribosomal RNA gene of gypsy moth Lymantria dispar L. against its larvae

5.8S ribosomal RNA plays an important role in protein synthesis and eukaryotic ribosome translocation. Contact DNA insecticides based on antisense fragments of 5.8S ribosomal RNA gene of gypsy moth Lymantria dispar L. showed prospective insecticidal activity on its larvae. The most pronounced insecticidal effect was found for antisense fragments 10 and 11 nucleotides long (oligoRIBO-10 and oligoRIBO-11), whereas 12 nucleotides long fragment (oligoRIBO-12) caused the lowest level of insect mortality. This data corresponds to results obtained earlier using rabbit reticulocyte and wheat germ extracts, where maximum inhibition of protein synthesis was observed when a relevant oligomer 10-11 nucleotides long was used, whilst longer chain lengths resulted in reduced inhibition. Using oligoRIBO-11 fragment we have shown penetration of antisense oligonucleotides to insect cells through insects’ exoskeletons. MALDI technique registered the penetration of the oligoRIBO-11 fragment into insect cells after 30 min and a significant response of insect cells to the applied oligonucleotide after 60 min, which indicates not only that the oligonucleotide enters the insect cells, but also the synthesis of new substances in response to the applied DNA fragment. Contact DNA insecticides developed from the L. dispar 5.8S ribosomal RNA gene provide a novel biotechnology for plant protection using unmodified antisense oligonucleotides