Modeling of graphene-based NEMS

The possibility of designing nanoelectromechanical systems (NEMS) based on relative motion or vibrations of graphene layers is analyzed. Ab initio and empirical calculations of the potential relief of interlayer interaction energy in bilayer graphene are performed. A new potential based on the density functional theory calculations with the dispersion correction is developed to reliably reproduce the potential relief of interlayer interaction energy in bilayer graphene. Telescopic oscillations and small relative vibrations of graphene layers are investigated using molecular dynamics simulations. It is shown that these vibrations are characterized with small Q-factor values. The perspectives of nanoelectromechanical systems based on relative motion or vibrations of graphene layers are discussed.Comment: 19 pages, 4 figure

Scintillator ageing of the T2K near detectors from 2010 to 2021

The T2K experiment widely uses plastic scintillator as a target for neutrino interactions and an active medium for the measurement of charged particles produced in neutrino interactions at its near detector complex. Over 10 years of operation the measured light yield recorded by the scintillator based subsystems has been observed to degrade by 0.9–2.2% per year. Extrapolation of the degradation rate through to 2040 indicates the recorded light yield should remain above the lower threshold used by the current reconstruction algorithms for all subsystems. This will allow the near detectors to continue contributing to important physics measurements during the T2K-II and Hyper-Kamiokande eras. Additionally, work to disentangle the degradation of the plastic scintillator and wavelength shifting fibres shows that the reduction in light yield can be attributed to the ageing of the plastic scintillator. The long component of the attenuation length of the wavelength shifting fibres was observed to degrade by 1.3–5.4% per year, while the short component of the attenuation length did not show any conclusive degradation

Characteristics of the magnetic control of separable ferrous impurities contained in raw construction materials

Currency of using the method of magnetic control of ferrous impurities for construction materials was noted. Especially it is important because of magnetic separators which are widely used for elimination of these impurities. There were shown the necessity of upgrading the present approach in order to realize the method of magnetic control. For example, it is necessary to take into account not only the rest of ferrous impurities (that is inevitable after limited numbers of operations) but also a factor of involving sand particles. The concrete proposal how to develop the existing system of magnetic control of ferrous impurities in construction materials subjected to magnetic separation, is stated. The experimental-calculation model for such control is also shown. The main parameters of such model were estimated on the example of quartz sand and feldspar. The errors of standard methods of magnetic control were revealed for the first time

Top of the Most Dangerous Food Parasites

According to the rating of the risk of infection by food parasites, which was published the World Health Organization (WHO) and the Food Agriculture Organisation in 2014, cryptosporidiosis is on the 5th place. It is a parasitic protozoan disease, belongs to the genus Cryptosporidium type Apicomplexa. About 20 species of Cryptosporidium are revealed and known now. The incubation period of cryptosporidiosis lasts from 4 to 14 days. The main and most typical clinical manifestation of the disease — a profuse watery diarrhea, as well as clinically possible cryptosporidiosis of the biliary tract and broncho-pulmonary (respiratory) cryptosporidiosis. Cryptosporidiosis diagnosis is based on laboratory studies of faeces (in vivo) and pathological material (posthumously), taking into account epizootic, clinical and postmortem data. Causal treatment is not developed. But it is possible to control the diarrhea caused by this infection. Specific preventive management of cryptosporidiosis is not developed. Personal hygiene measures are necessary. The 6th most dangerous food parasitosis is Entamoeba histolytica. This intestinal protozoa disease is characterized by ulcerative lesions of the colon, chronic protracted course with the risk of the formation of abscesses in the liver and various organs. The causative agent of ame­biasis — Entamoeba histolytica — belongs to the genus Entamoeba, family Entamoebidae, the simplest type — Protozoa. According to the recommendations of the WHO Expert Committee (1970), there are three clinical forms of amebiasis: intestinal, extra-intestinal and skin. Diagnostic microscopy of the native smears of fresh feces in saline solution and smears stained with Lugol’s solution is carried out. In the presence of clinical signs of intestinal amebiasis and negative results of parasitological studies, serological tests are used based on the detection of specific antibodies against Entamoeba. There are several groups of drugs for the treatment of amoebiasis that act at different stages of the disease: drugs with direct contact action, drugs acting on the tissue amoebocytes, drugs with universal combined action, can be used in the treatment of all forms of amoebiasis: metronidazole (trichopolum), furamide. Duration of follow-up of parasite carriers lasts until their complete recovery

Conditions of formation and forecast of natural reservoirs in clinoform complex of the Lower Cretaceous of the Barents-Kara shelf

Unique Leningradsky and Rusanovsky gascondensate fields in the Barrem-Cenomanian layer are discovered in the Kara Sea. Non-industrial accumulations of oil and gas have been discovered in the Lower Cretaceous sediments of the western part of the Barents Sea shelf. However, the structure and oil and gas potential of the Lower Cretaceous sediments of the Barents-Kara shelf remain unexplored. Based on the seismic-stratigraphic and cyclostratigraphic analysis, a regional geological model of the Lower Cretaceous deposits of the Barents-Kara shelf was created, the distribution area and the main stages of the accumulation of clinoforms were identified. As a result of a detailed analysis of the morphology of clinoform bodies, paleogeographic conditions were restored in the Early Cretaceous and a forecast of the distribution of sandy reservoirs was give

НОВЫЙ ПОДХОД К СИНТЕЗУ АЗОТ- И КИСЛОРОДСОДЕРЖАЩИХ МАКРОЦИКЛИЧЕСКИХ СОЕДИНЕНИЙ

Alkylation of difuryl-substituted piperidones with 3-benzyl-1,5,3-dioxazepane in the presence of trimethylsilyl chloride leads to the formation of a wide range of new macrocycles.Алкилирование дифурилзамещенных пиперидонов 3-бензил-1,5,3-диоксазепаном в присутствии триметилхлорсилана приводит к получению ряда новых макроциклических соединени

Facile synthesis of pyrrolo[2,1-a]isoquinolines by domino reaction of 1-aroyl-3,4-dihydroisoquinolines with conjugated ketones, nitroalkenes and nitriles

Abstract: A convenient protocol for the synthesis of 5,6-dihydropyrrolo[2,1-a]isoquinolines with various electron-withdrawing substituents at C-2 atom is described. This approach is based on the two-component domino reaction of 1-aroyl-3,4-dihydroisoquinolines with α,β-unsaturated ketones, nitroalkenes and acrylonitrile. Depending on the selected substrates, the reaction was performed in TFE under reflux or under microwave irradiation. Only for the two examples, a transition metal catalyst was used. Graphic abstract: [Figure not available: see fulltext.] © 2020, Springer Nature Switzerland AG

New approaches to the synthesis of benzo[h]pyrroloisoquinoline derivatives

An effective strategy for the synthesis of benzo[h]pyrrolo[2,1-a]isoquinoline derivatives has been developed. The process can be described as a one-pot domino reaction that consists of an initial Michael addition, intramolecular cyclization, and subsequent transformations leading to the formation of the desired products. A wide range of structurally diverse hydrogenated benzo[h]pyrrolo[2,1-a]isoquinolines were obtained in 34–98% yield. This strategy represents an efficient catalyst-free procedure that allows the synthesis of previously inaccessible compounds. © 2019 Elsevier Lt

IS ROUTINE VACCINATION AGAINST HEPATITIS A NEEDED IN CHILDREN? EVALUATION OF PROPHYLAXIS WITH VACCINES IN SEVERAL REGIONS OF RUSSIAN FEDERATION

The article presents data on effectiveness of routine vaccination against hepatitis A in children. The results of program of specific prophylaxis of hepatitis A in several regions of Russian Federation are analyzed. Perspectives of implementation of obtained experience are discussed.Key words: children, hepatitis A, routine vaccination, regional vaccination calendars.(Voprosy sovremennoi pediatrii — Current Pediatrics. 2010;9(6):123-126