Near Earth space sporadic radio emission busts occurring during sunrise

During the period of low solar activity at sunrise the effect of sporadic high frequency near Earth space radio emission was experimentally discovered at middle latitudes. The possible mechanism of its origin is discussed

Chaotic Observer-based Synchronization Under Information Constraints

Limit possibilities of observer-based synchronization systems under information constraints (limited information capacity of the coupling channel) are evaluated. We give theoretical analysis for multi-dimensional drive-response systems represented in the Lurie form (linear part plus nonlinearity depending only on measurable outputs). It is shown that the upper bound of the limit synchronization error (LSE) is proportional to the upper bound of the transmission error. As a consequence, the upper and lower bounds of LSE are proportional to the maximum rate of the coupling signal and inversely proportional to the information transmission rate (channel capacity). Optimality of the binary coding for coders with one-step memory is established. The results are applied to synchronization of two chaotic Chua systems coupled via a channel with limited capacity.Comment: 7 pages, 6 figures, 27 reference

Controlled Synchronization of One Class of Nonlinear Systems under Information Constraints

Output feedback controlled synchronization problems for a class of nonlinear unstable systems under information constraints imposed by limited capacity of the communication channel are analyzed. A binary time-varying coder-decoder scheme is described and a theoretical analysis for multi-dimensional master-slave systems represented in Lurie form (linear part plus nonlinearity depending only on measurable outputs) is provided. An output feedback control law is proposed based on the Passification Theorem. It is shown that the synchronization error exponentially tends to zero for sufficiantly high transmission rate (channel capacity). The results obtained for synchronization problem can be extended to tracking problems in a straightforward manner, if the reference signal is described by an {external} ({exogenious}) state space model. The results are applied to controlled synchronization of two chaotic Chua systems via a communication channel with limited capacity.Comment: 8 pages, 2 figure

Synthesis and anticancer properties of 1-(2-isopropyl-5-methylphenoxymethyl)-3R-4-aryl-5,6,7,8-tetrahydro-2,2а,8а-triazacyclopenta[cd]azulene derivatives

In recent years, attention to itself is attracted to the problem of treatment of cancer that is caused by increase in patients, especially of working age. Therefore, the enlargement of the arsenal of anticancer medicines of a wide spectrum of action is actual. The purpose of the study was to synthesize substances with potentially antitumor properties in a series 1-(2-isopropyl-5-methylphenoxymethyl)-3R-4-aryl-5,6,7,8-tetrahydro-2,2а,8а-triazacyclopenta[cd]azulene derivatives and to study the effect of synthesized compounds on inhibition of growth (or their destruction) of a wide range of cancer. The objects of the study were derivatives of 1-(2-isopropyl-5-methylphenoxymethyl)-3R-4-aryl-5,6,7,8-tetrahydro-2,2а,8а-triazacyclopenta[cd]azulene, which were synthesized by refluxing 3-(2-isopropyl-5-methylphenoxymethyl)-6,7,8,9-tetrahydro-5Н-[1,2,4]triazolo[4,3-a]azepine with с appropriate α-halogenketones in ethyl acetate and further cyclization in an alkaline medium. Использовали данные NMR 1Н spectroscopy data were used. The primary evaluation of anticancer activity was carried out National Cancer Institute of Health, USA within the Development Therapeutic Program. A series of new of 1-(2-isopropyl-5-methylphenoxymethyl)-3R-4-aryl-5,6,7,8-tetrahydro-2,2а,8а-triazacyclopenta[cd]azulene derivatives was synthesized, their structure and purity were confirmed by NMR 1Н spectroscopy. The anticancer activity of the synthesized compounds was studied both at a concentration of 10-5 mol/l and in a concentration gradient of 10-4‒10-8 mol/l in experiments in vivo on cancer cell lines. It is shown that insertion of methyl group into position 3 of heterocyclic system of the basic structure of 4-aryl-5,6,7,8-tetrahydro-2,2a,8a-triazacyclopenta[cd]azulene leads to an increase in the anticancer effect. It is found that the tested compounds showed high anticancer effect on all types of cancer cell lines investigated – leukemia, non-small cell lung cancer, colon cancer, CNS cancer, melanoma, ovarian cancer, renal cancer, prostate cancer and breast cancer

Empirical Evaluation of Educational Service Quality in the Current Higher Education System

During the transition to the mixed education model during the Covid-19 pandemic, some issues have emerged in the matter of providing and supporting the quality of university education in all countries, including educational programs' relevance to the demands of the labor market, expectations of students and their families, digital transformation of the educational process, and economic stability of institution networks. The purpose of the research was to evaluate the quality of educational services in the higher education systems of Indonesia and Russia. The study systematized several essential factors for achieving educational service quality in the current higher education systems, given the limitations imposed by Covid-19. Following this objective, the study utilized a quantitative approach, adopting the SERVQUALmodel that measures the service quality across five service dimensions: tangibility, reliability, responsiveness, assurance, and empathy. The model aided the development of the questionnaire to assess the quality of the educational services of Indonesian and Russian universities. The questionnaire included 25 close-ended questions on two scales: one to measure the students' expectations regarding the quality of educational services and the other to measure the students' current perceptions. A snowball technique was used to recruit students from Indonesian and Russian universities as participants in the study. The students were asked to assess the educational services of their universities based on their initial expectations and current perceptions. Overall, the students of both countries revealed that they had high expectations from the educational services of their universities. However, the current perceptions of the Russian students regarding the quality of educational services provided by their universities are higher and more positive than the perceptions of the Indonesian students regarding the quality of educational services being delivered to them. The findings of the study have implications for education practitioners. Doi: 10.28991/ESJ-2022-SIED-05 Full Text: PD

Modern microwave methods in solid state inorganic materials chemistry: from fundamentals to manufacturing

No abstract available

The use of nonsteroidal anti-inflammatory drugs for the treatment of facial pain in practice

Studies have shown that the drug ibuprofen is effective for the relief of pain in the facial area, allowing the continuation of dental treatment. Clinical experience has shown that 87% of patients were satisfied with the result of pain relief.Проведенные исследования показали, что препарат ибупрофен является эффектив-ными для купирования болевого синдрома в лицевой области, что позволяет дальнейшее проведение стоматологического лечения. Клинический опыт показал, что 87% пациентов были удовлетворены результатом снятия болевого синдрома

Calibration of RADMON radiation monitor onboard Aalto-1 CubeSat

RADMON is a small radiation monitor designed and assembled by students of University of Turku and University of Helsinki. It is flown on-board Aalto-1, a 3-unit CubeSat in low Earth orbit at about 500 km altitude. The detector unit of the instrument consists of two detectors, a Si solid-state detector and a CsI(Tl) scintillator, and utilizes the ΔE-E technique to determine the total energy and species of each particle hitting the detector. We present the results of the on-ground and in-flight calibration campaigns of the instrument, as well as the characterization of its response through extensive simulations within the Geant4 framework. The overall energy calibration margin achieved is about 5%. The full instrument response to protons and electrons is presented and the issue of proton contamination of the electron channels is quantified and discussed

Nickel-Catalyzed Carbon–Carbon Bond-Forming Reactions of Unactivated Tertiary Alkyl Halides: Suzuki Arylations

The first Suzuki cross-couplings of unactivated tertiary alkyl electrophiles are described. The method employs a readily accessible catalyst (NiBr[subscript 2]·diglyme/4,4′-di-tert-butyl-2,2′-bipyridine, both commercially available) and represents the initial example of the use of a group 10 catalyst to cross-couple unactivated tertiary electrophiles to form C–C bonds. This approach to the synthesis of all-carbon quaternary carbon centers does not suffer from isomerization of the alkyl group, in contrast with the umpolung strategy for this bond construction (cross-coupling of a tertiary alkylmetal with an aryl electrophile). Preliminary mechanistic studies are consistent with the generation of a radical intermediate along the reaction pathway.National Institute of General Medical Sciences (U.S.) (R01-GM62871)Merck Research Laboratories (Summer Fellowship