Search

In this article, we present the synthesis and characterization of new acyclic pyridine-containing polyaminocarboxylate ligands H4aPyta and H6aPyha, which differ in structural rigidity and the number of chelating groups. Their abilities to form complexes with Cu2+, Ga3+, Y3+, and Bi3+ cations, as well as the stability of the complexes, were evaluated by potentiometric titration method, radiolabeling with the corresponding radionuclides, in vitro studies, mass spectrometry, and HPLC. The structures of the resulting complexes were determined using NMR spectroscopy and DFT calculations. The results obtained made it possible to evaluate the influence of the structural features of the complexes on their stability. The developed chelators H4aPyta and H6aPyha were proved to be promising for further research in the field of radiopharmaceuticals. [ABSTRACT FROM AUTHOR]

This study examined the efficiency of teaching Russian as a foreign language (L2) in two groups of students – the first benefited from the e-learning platform's capabilities (experimental), and the second underwent a traditional in-class course. Students learning Russian as L2 at People's Friendship University of Russia (Moscow, Russia) were enrolled in the experiment. The research sample comprised 75 individuals distributed to three experimental groups and 33 individuals allocated to three control groups. All data obtained as a result of the study were statistically analyzed. In order to study the overall effect of using the iSpring platform, the research outcomes were combined by Stouffer's Z-score method. Together with this, at each examination stage, repeated analysis of variance (ANOVA) was conducted. Students' progress in learning Russian was evaluated by way of pre- and post-testing. After the experiment finished, all respondents were surveyed to analyze their perception of the effectiveness, convenience, and satisfaction of the chosen learning mode. The study found that students from experimental groups spent significantly more time for learning, demonstrating better performance. It was remarked that iSpring's adaptive learning features contribute to improving students' performance by encouraging them to learn better and faster. [ABSTRACT FROM AUTHOR]

When studying the dynamics of morbidity and mortality, one should not limit ourselves to analyzing general trends. Interesting information can be obtained from the analysis of deviations in morbidity and mortality from the general dynamics. Comparison of the cases of morbidity or death for adjacent time intervals allows us to find out whether the changes in conditions were for short periods of time and whether the cases of morbidity or death were independent. The article consists of two parts: Study of the probability distribution (CDF) of the difference between two independent observations of the Poisson distribution; Application of the results to analyze the morbidity and mortality trends by day for the new coronavirus infection. For the distribution function of the module of difference between two independent observations of the Poisson distribution, an analytical expression has been obtained that allows to get an exact solution. A program has been created, whose software can be downloaded at http://1mgmu.com/nau/DeltaPoisson/DeltaPoisson.zip. An approximate solution that does not require complex calculations has also been obtained, which can be used for an average of more than 20. If real difference is greater than expected, it may be in the following cases: morbidity or mortality varies considerably during the day. That could happen, for example, if the registered number of morbidity on Saturday and Sunday is less than on weekdays due to the management model of the health system, or if the cases are not independent; for example, due to the active identification of infected people among those who have come into contact with the patient. If the difference is less than expected, it may be due to external limiting factors, such as a shortage of test systems for making a diagnosis, a limited number of pathologists to determine the cause of death, and so on. In the analysis of the actual data for COVID-19 it was found that for Poland and Russia, excluding Moscow, the difference in the number of cases and deaths is greater than expected, while for Moscow--less than expected. This may be due to the information policy--the effort to somehow reassure Moscow's population, which in the spring of 2020 had a high incidence rate of the new coronavirus infection. [ABSTRACT FROM AUTHOR]

The paper presents the results of the study on the transport systems in metropolises by stating the interdisciplinary problems and prospects of applying the environmental and economic approach to the optimization of transport communication in megacities. The main problems of transport communications in large cities have been considered. The world experience in managing transport systems is analyzed. Priority directions for the implementation of environmental and economic tasks of transport industry management using the economic and mathematical approach have been established. It has been established that the performance indicators of the functioning of the megalopolis transport system depend on the work of the service provider. The most effective solution is to ensure that vehicles are working properly, that the vehicles are fully loaded and that they are on schedule. Performance indicators of the functioning of the megalopolis transport system on the part of the consumer of services: the coefficient of determination was 0.9493, the static probability p = 0.2067 standard deviation was 7.9428, the variance did not exceed 0.1015. The correlation of actual and planned results exceeded r2>0.7051; and was described by the equation y = 1.6746 + 0.844x. Logistic models for performance improvement of the transportation system were offered. [ABSTRACT FROM AUTHOR]