Twisted bilayer graphene (TBG) is a two-dimensional chiral material whose optical activity is remarkably strong for its atomic thickness. While the chiral optical properties of TBG are currently well understood, the optical activity of quantum dots (QDs) made of TBG has not been analyzed so far. Here, we comprehensively analyze the chiral optical properties of TBG QDs with hexagonal, triangular, and rhomboid symmetries. We show that the dissymmetry factors of TBG QDs can reach 10 −2 , greatly exceeding the dissymmetry factors of semiconductor QDs and small chiral molecules. The strong optical activity of TBG QDs is due to the out-of-plane polarized transitions of the p z electrons and can be controlled by changing the size and shape of the QDs. These unique features make TBG QDs highly attractive for application in chiral nanophotonics.

The charged quaternary ammonium compounds – methyl, ethyl and benzyl viologens – generate reactive oxygen species in photosynthetic cells. Three independent methyl viologen‐resistant spontaneous mutants of Synechocystis sp. PCC 6803 were identified, in which the conserved R115 residue of the Slr1174 protein was replaced with G115, L115 and C115. The Slr1174 protein of the DUF990 family is related to the permease subunit of an ABC‐2‐type transporter and its R115 mutation was found to be solely responsible for the observed methyl viologen resistance. Bioinformatic analysis showed that in various bacterial genomes, two genes encoding another permease subunit and the ATPase component of an ATP‐binding cassette transporter form putative operons with slr1174 orthologs, suggesting that the protein products of these genes may form functional transporters. The corresponding genes in Synechocystis sp. PCC 6803, i.e. slr0610 for the permease and slr1901 for the ATPase, did not form such an operon. However, insertional inactivation of any slr1174, slr0610 or slr1901 genes in both the wild‐type and the R115‐resistant mutant resulted in increased sensitivity to methyl, ethyl and benzyl viologens; moreover, single‐ and double‐insertion mutants did not differ in their viologen sensitivity. Our data suggest that Slr1901, Slr1174 and Slr0610 form a heteromeric ATP‐binding cassette‐type viologen exporter, in which each component is critical for viologen extrusion. Because the greatest increase in mutant sensitivity was observed in the case of ethyl viologen, the three proteins have been named EvrA (Slr1901), EvrB (Slr1174) and EvrC (Slr0610). This is the first report of a function for a DUF990 family protein.

Noroviruses infect a wide range of mammals and are the major cause of gastroenteritis in humans. Recombination at the junction of ORF1 encoding nonstructural proteins and ORF2 encoding major capsid protein VP1 is a well-known feature of noroviruses. Using all available complete norovirus sequences, we systematically analyzed patterns of natural recombination in the genus Norovirus both throughout the genome and across the genogroups. Recombination events between nonstructural (ORF1) and structural genomic regions (ORF2 and ORF3) were found in all analyzed genogroups of noroviruses, although recombination was most prominent between members of GII, the most common genogroup that infects humans. The half-life times of recombinant forms (clades without evidence of recombination) of human GI and GII noroviruses were 10.4 and 8.4–11.3 years, respectively. There was evidence of many recent recombination events, and most noroviruses that differed by more than 18% of nucleotide sequence were recombinant relative to each other. However, there were no distinct recombination events between viruses that differed by over 42% in ORF2/3, consistent with the absence of systematic recombination between different genogroups. The few inter-genogroup recombination events most likely occurred between ancient viruses before they diverged into contemporary genogroups. The recombination events within ORF1 or between ORF2/3 were generally rare. Thus, noroviruses routinely exchange full structural and nonstructural blocks of the genome, providing a modular evolution.

начальник юридического отдела акционерного общества «Холдинговая компания "Сибирский Цемент"», кандидат юридических наук Актуальные правовые проблемы взыскания долга у физического лица*  * Статья подготовлена с использованием нормативных правовых актов, материалов правоприменительной и судебной практики, содержащихся в СПС «КонсультантПлюс».

In hypoxic shock, serotonin content in the spleen and epinephrine content in the adrenals are lowered. Administration of the peptide mixture FMRFa--thyroliberin--semax 15 rain prior to hypoxia significantly prolongs the time of posture loss and abolishes the effect of hypoxia on the level of biogenic amines; the concentration of lipid peroxidation products decreases considerably.