Total Polarisation Conversion in Two-dimensional Electron System under Cyclotron Resonance Conditions

The polarisation conversion of a linear polarised electromagnetic wave incident onto a two-dimensional (2D) electron system at an angle is theoretically studied. We consider the 2D system located at the interface between two dielectric media with different dielectric constants. An external dc magnetic field is assumed to be directed along the normal to the 2D electron layer. In such a configuration the cyclotron-polaritons (CPs) in 2D electron system can be excited with the frequencies in the vicinity of the cyclotron frequency. Under the CPs excitation the resonance polarisation conversion of electromagnetic wave greatly increases in the system. In the absence of the electron scattering in 2D system, the polarisation conversion reaches 100% at a certain value of the angle of incidence which is more than the total reflection angle. Extremely high polarisation conversion takes place in a quite wide range of variation of the angle of incidence. High polarisation conversion efficiency (above 80%) remains when the actual electron scattering in the 2D system on GsAs is taken into account. The considered phenomena may be taken up in polarisation spectroscopy of 2D electron systems.Comment: 7 pages, 5 Postscript figure

ОБОБЩЕНИЕ ОПЫТА ИСПОЛЬЗОВАНИЯ ДИСТАНЦИОННЫХ ТЕХНОЛОГИЙ В УСЛОВИЯХ УДАЛЕННОГО ОБУЧЕНИЯ

The article discusses the problems of organizing remote learning that have arisen due to the COVID-19 pandemic, provides the advantages and disadvantages of using various software tools and Learning Management Systems.The article discusses the problems of organizing remote learning that have arisen due to the COVID-19 pandemic, provides the advantages and disadvantages of using various software tools and Learning Management Systems

IMPROVEMENT OF ANTHROPOGENIC ENVIRONMENTAL LOADS ASSESSMENT METHODS USING MODERN INFORMATION TECHNOLOGIES

The innovative path of human development is characterized by the active use of information technology in any field. This is due to the rapid development of high technologies and, accordingly, with the advent of new data analysis tools. One of the rapidly developing areas of application of information technology, to which there is great interest in society, the state, commercial organizations, is high-quality forecasting.The innovative path of human development is characterized by the active use of information technology in any field. This is due to the rapid development of high technologies and, accordingly, with the advent of new data analysis tools. One of the rapidly developing areas of application of information technology, to which there is great interest in society, the state, commercial organizations, is high-quality forecasting

In Vitro and In Vivo Trypanosomicidal Action of Novel Arylimidamides against Trypanosoma cruzi

ABSTRACT Arylimidamides (AIAs) have been shown to have considerable biological activity against intracellular pathogens, including Trypanosoma cruzi , which causes Chagas disease. In the present study, the activities of 12 novel bis-AIAs and 2 mono-AIAs against different strains of T. cruzi in vitro and in vivo were analyzed. The most active was m -terphenyl bis-AIA (35DAP073), which had a 50% effective concentration (EC 50 ) of 0.5 μM for trypomastigotes (Y strain), which made it 26-fold more effective than benznidazole (Bz; 13 μM). It was also active against the Colombiana strain (EC 50 = 3.8 μM). Analysis of the activity against intracellular forms of the Tulahuen strain showed that this bis-AIA (EC 50 = 0.04 μM) was about 100-fold more active than Bz (2 μM). The trypanocidal effect was dissociated from the ability to trigger intracellular lipid bodies within host cells, detected by oil red labeling. Both an active compound (35DAP073) and an inactive compound (26SMB060) displayed similar activation profiles. Due to their high selectivity indexes, two AIAs (35DAP073 and 35DAP081) were moved to in vivo studies, but because of the results of acute toxicity assays, 35DAP081 was excluded from the subsequent tests. The findings obtained with 35DAP073 treatment of infections caused by the Y strain revealed that 2 days of therapy induced a dose-dependent action, leading to 96 to 46% reductions in the level of parasitemia. However, the administration of 10 daily doses in animals infected with the Colombiana strain resulted in toxicity, preventing longer periods of treatment. The activity of the combination of 0.5 mg/kg of body weight/day 35DAP073 with 100 mg/kg/day Bz for 10 consecutive days was then assayed. Treatment with the combination resulted in the suppression of parasitemia, the elimination of neurological toxic effects, and survival of 100% of the animals. Quantitative PCR showed a considerable reduction in the parasite load (60%) compared to that achieved with Bz or the amidine alone. Our results support further investigations of this class with the aim of developing novel alternatives for the treatment of Chagas disease

Criteria of ecological plasticity, stability, and adaptability of potato varieties based on yield

The influence of the physiological and biochemical parameters of the leaves of 12 potato varieties on the formation, plasticity, and stability of the potato crop has been studied. The experiments were carried out on the territory of the Samara Research Institute of Agriculture – branch of the SamSRC RAS (53°03’ N, 49°25’ E) in the period 2019-2022. Average potato yields varied in the range of 14.2-25.7 t/ha. The highest yield was the first planting year. With an increase in the duration of reproduction, yield losses ranged from 25 to 50% due to a decrease in the mass of tubers. The coefficient of variation in yield varied in the range of 24-60% depending on the genotype. Criteria of ecological plasticity and stability of potato of different genetic origin are such indicators as leaf dryness or its hydration, the content of phenolic compounds in the leaves, the content of lipid oxidation products, and the state of the membranes. The amplitudes of variation of leaf indicators can serve as a measure of plasticity. Adaptive capacity is related to the content of proline, the ratio of membrane lipids and proteins, and the number of stomata

Minor Groove Binding Compounds That Jump a GC Base Pair and Bind to Adjacent AT Base Pair Sites †

Most A/T specific heterocyclic diamidine derivatives need at least four A/T base pairs for tight binding to the DNA minor groove. Addition of a GC base pair to A/T sequences typically causes a large decrease in binding constant. The ability to target biologically important sequences of DNA could be significantly increased if compounds that could recognize A/T sites with an intervening GC base pair could be designed. The kinetoplast DNA sequence of parasitic microorganisms, for example, contains numerous three A/T binding sites that are separated by a single G. A series of compounds were prepared to target the AAAGTTT sequence as a model system for discovery of “G-jumpers”. The new synthetic compounds have two aromatic-amidine groups for A/T recognition, and these are connected through an oxy-methylene linker to cross the GC. CD experiments indicated a minor groove binding mode, as expected, for these compounds. Tmax, surface plasmon resonance, and isothermal titration calorimetry experiments revealed 1:1 binding to the AAAGTTT sequence with an affinity that depends on compound structure. Benzimidazole derivatives gave the strongest binding and had generally good solution properties. The binding affinities to the classical AATT sequence were similar to that for AAAGTTT for these extended compounds, but binding was weaker to the AAAGCTTT sequence with two intervening GC base pairs. Binding to both AAAGTTT and AATT was enthalpy driven for strong binding benzimidazole derivatives

Isothermal Microcalorimetry, a New Tool to Monitor Drug Action against Trypanosoma brucei and Plasmodium falciparum

Isothermal microcalorimetry is an established tool to measure heat flow of physical, chemical or biological processes. The metabolism of viable cells produces heat, and if sufficient cells are present, their heat production can be assessed by this method. In this study, we investigated the heat flow of two medically important protozoans, Trypanosoma brucei rhodesiense and Plasmodium falciparum. Heat flow signals obtained for these pathogens allowed us to monitor parasite growth on a real-time basis as the signals correlated with the number of viable cells. To showcase the potential of microcalorimetry for measuring drug action on pathogenic organisms, we tested the method with three antitrypanosomal drugs, melarsoprol, suramin and pentamidine and three antiplasmodial drugs, chloroquine, artemether and dihydroartemisinin, each at two concentrations on the respective parasite. With the real time measurement, inhibition was observed immediately by a reduced heat flow compared to that in untreated control samples. The onset of drug action, the degree of inhibition and the time to death of the parasite culture could conveniently be monitored over several days. Microcalorimetry is a valuable element to be added to the toolbox for drug discovery for protozoal diseases such as human African trypanosomiasis and malaria. The method could probably be adapted to other protozoan parasites, especially those growing extracellularly

Improvement of anthropogenic environmental loads assessment methods using modern information technologies

The innovative path of human development is characterized by the active use of information technology in any field. This is due to the rapid development of high technologies and, accordingly, with the advent of new data analysis tools. One of the rapidly developing areas of application of information technology, to which there is great interest in society, the state, commercial organizations, is high-quality forecasting

Pilot study of the safety and efficacy of angiogenic therapy in diabetic foot syndrome

BACKGROUND: The syndrome of diabetic foot remains the main cause of non-traumatic amputation of the lower extremity in the world. Even with the provision of comprehensive medical care in the conditions of a specialized center, 10-15% of patients do not succeed in healing the ulcerative defect due to the ischemic component. AIMS: The objective of this study is evaluation of safety and efficacy of pl-VEGF165 transfer in patients with neuroischemic type of diabetic foot syndrome. METHODS: The pilot study included 35 diabetic patients with neuroischemic foot ulcers (Wagner stage 1-2) who were not candidates for revascularization procedures (NCT02538705). The patients were closely monitored after repeated pl-VEGF165 intramuscular gene transfer (2,4 mg) at 1, 3, and 6 months after treatment. The primary efficacy endpoint was the surface area of the ulcers (sq.cm), the secondary endpoints were transcutaneous oxygen tension (Tcp02), ankle-brachial index (ABI), neuropathy disability score (NDS), neuropathy symptoms score (NSS), and Michigan neuropathy screening instrument (MNSI). Adverse events were monitored throughout the study. RESULTS: The use of pl-VEGF165 as part of complex treatment allowed to achieve wound healing in 65,7% of patients with chronic ulcerative defects, the safety of the target limb was 84%. Carrying out therapeutic angiogenesis as a part of the combined therapy ensured a reduction in the average area of the resistant to treatment defects from 3.6 [1.0; 7.05] cm2 to 0.0 [0.0;2.0] cm2 (p=0,001), which correlated with an increase in the TcPo2 index by 15% from 35 [29.5; 40.5] to 40.5 [36.0; 46.5] mm Hg (p= p=0,005) and in the ABI by 16% from 0.96 [0.82;1.08] to 1.11 [0.85; 1.24] (p=0,062). The decrease in the signs of diabetic neuropathy was determined - the scores of NSS scales and VAT decreased from 6,5 [5.75; 8.0) to 6.0 [5.25; 7.0] (p=0,004) and from 9.0 [8.0; 13.5] to 8.0 [7.0; 12.7] (p=0,001), respectively. No adverse effects associated with the use of pl-VEGF165 were recorded. CONCLUSIONS: Thus, preliminary results of the pilot study show that the use of pl-VEGF165 gene transfer in combination therapy allows for complete healing of neuroischemic diabetic foot ulcers in the majority of patients