Vitamin B6-based fluorescence chemosensor for selective detection of F- ions: design, synthesis, and characterization.

The present paper reports on the synthesis and characterization of a new chemosensor for fluoride ions, a hydrazone derived from pyridoxal 5'-phosphate and benzothiazole. The structure of the chemosensor was confirmed using 1H and 13C NMR, FT-IR and mass spectroscopy. The conformational diversity of the chemosensor influencing the sensor activity was studied by the quantum chemistry methods on the B3LYP/6-311++G(d, p) (H, C, N, O, P, S) level, and the optimal structure of the chemosensor was chosen. The selective capability of detecting F- in the aqueous solution, which also contains Cl-, Br-, I-, NCS-, ClO4-, HSO4-, and NO3- was demonstrated. The detection limit (LOD) for fluoride ions was 0.22 µM as determined by the 3σ method. The turn-on effect in the presence of fluoride ions is based on the deprotonation of the chemosensor and its subsequent aggregation in DMSO. In addition, the chemosensor was used for the detection and estimation of F- in real samples using fluorescence spectroscopy.

Interaction of 5-[4'-(N-Methyl-1,3-benzimidazol-2-yl)phenyl]-10,15,20-tri-(N-methyl-3'-pyridyl)porphyrin Triiodide with SARS-CoV-2 Spike Protein.

The results of experimental studies of the interaction of the S-protein with a monohetaryl-substituted porphyrin containing a benzimidazole residue are presented. It has been revealed that the S-protein forms high-affinity complexes with the specified porphyrin. The porphyrin binding by the SARS-CoV-2 S-protein has proceeded stepwise; at the first stage, the driving force of the complexation is electrostatic interaction between the surface negatively charged regions of the protein and cationic substituents of the porphyrin. At the second stage, the target complex of the S-protein with the porphyrin is formed. It has been established that the introduction of 5-[4'-(N-methyl-1,3-benzimidazol-2-yl)phenyl]-10,15,20-tri-(N-methyl-3'-pyridyl)porphyrin triiodide into a solution of the S-protein complex with the angiotensin-converting enzyme leads to the replacement of the latter with the porphyrin. Displacement of the angiotensin-converting enzyme from the complex with the S-protein under the action of 5-[4'-(N-methyl-1,3-benzimidazol-2-yl)phenyl]-10,15,20-tri-(N-methyl-3'-pyridyl)porphyrin triiodide is the experimental evidence for the porphyrin binding at the receptor-binding domain of the S-protein.

Synthesis of Hetaryl-Substituted Asymmetric Porphyrins and Their Affinity to SARS-CoV-2 Helicase.

Novel porphyrin compounds containing benzothiazole, benzoxazole, and benzimidazole moieties have been prepared and their structures have been confirmed. Molecular docking of non-symmetric hetaryl-substituted porphyrins and chlorin e6 with SARS-CoV-2 helicase has been carried out. The affinity of hetaryl-substituted porphyrins to this protein has been found significantly higher than that of the drugs approved by the FDA and chlorin e6. The structure of the complexes of SARS-CoV-2 helicase with the considered macroheterocyclic compounds has been analyzed. Possible ways to inhibit and photoinactivate SARS-CoV helicase have been suggested basing on the localization of porphyrins and chlorin e6 in the helicase domains.

[Contrast induced nephropathy in the older age group patients].

This review devoted to actual medical problem that exists at a crossroad of cardiology, nephrology and radiology. Contrast induced nephropathy (CIN) is an important medical issue and its frequency is increasing last years. This disease may account for severe complications, including renal failure and even fatal outcome. We investigated contemporary sources to present epidemiology, pathogenesis, diagnosis, treatment and prophylaxis of CIN.

[Population density of Ixodes persulcatus ticks (Ixodidae) in the western Sikhote-Alin]. / Plotnost' naseleniia pastbishchnykh iksodovykh kleshchei (Ixodidae) v Zapadnom Sikhoté-Aline.

The paper presents data on the population density of active ticks in different landscape zones of West Sykhote-Alyn as well as the material on the absolute abundance of ticks in four experimental 400 m2 areas. The abundance of active Ixodes persulcatus and Haemaphysalis japonica on vegetation at the peak of their activity was found to amount to half of all hibernated adult ticks.

[Distribution and ecology of Ixodes pavlovskyi (Ixodidae) in Sykhote-Alin]. / Rasprostranenie i ekologiia Ixodes Pavlovskyi (Ixodidae) v Sikhote-Aline.

I. pavlovskyi is absent from the eastern macroslope of Sykhote--Alin, rare in the central part of the ridge and is quite common in western Sykhote--Alin where it accounts for no more than 10% of total collections with I. persulcatus. An average density of ticks in forests of western Sykhote--Alin is 50 to 80 active adults per hectare, maximum density - 150 specimens. Larvae feed on various small mammals and birds, nymphs--on birds and mammals larger than Sibirian chipmunk. Adults feed on hedgehogs, hares and birds, preferrence being given to hazel hens.

[Density and distribution of pasture Ixodes in the Central Sikhote-Alin]. / Plotnost' i raspredelenie pastbishchnykh iksodovykh kleshchei v Tsentral'noi Sikhote-Aline

Data are given on the density of active ticks in different landscapes in the central part of Sikhote-Alin. The character of the ticks distribution (regular, even, contagious) in dependence on the relief and vegetation is analysed.

[Experience in the absolute calculation of pasture ixodid ticks (Parasitiformes, Ixodidae) on the eastern macroslopes of Sikhoté-Alin]. / Opyt absoliutnogo ucheta pastbishchnykh iksodovykh kleschei (Parasitiformes, Ixodidae) na vostochnom makrosklone Sikhoté-Alinia

A new technique is suggested for absolute registration of adult ixodid ticks with an improved furrow plough. Due to this the number of ticks can be estimated per square unit to various biotopes. As a result of registrations conducted in 1973 the density of ticks populations from the main landscape zones of eastern Sikhote-Alin (from watershed spruce-abietic forests to coastal oak woods) was estimated for the first time.