9 research outputs found

    TOTAL IONIZING DOSE EFFECTS AND RADIATION TESTING

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    Total ionizing dose (TID) effects and radiation tests of complex multifunctional Very-large-scale integration (VLSI) integrated circuits (ICs) rise up some particularities as compared to conventional "simple" ICs. The main difficulty is to organize informative and quick functional test dirctly under irradiation. Functional tests approach specified for complex multifunctional VLSI devices is presented and the basic radiation test procedure is discussed in application to some typical examples. 

    Structural insights into thrombolytic activity of destabilase from medicinal leech

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    Destabilase from the medical leech Hirudo medicinalis belongs to the family of i-type lysozymes. It has two different enzymatic activities: microbial cell walls destruction (muramidase activity), and dissolution of the stabilized fibrin (isopeptidase activity). Both activities are known to be inhibited by sodium chloride at near physiological concentrations, but the structural basis remains unknown. Here we present two crystal structures of destabilase, including a 1.1 Å-resolution structure in complex with sodium ion. Our structures reveal the location of sodium ion between Glu34/Asp46 residues, which were previously recognized as a glycosidase active site. While sodium coordination with these amino acids may explain inhibition of the muramidase activity, its influence on previously suggested Ser49/Lys58 isopeptidase activity dyad is unclear. We revise the Ser49/Lys58 hypothesis and compare sequences of i-type lysozymes with confirmed destabilase activity. We suggest that the general base for the isopeptidase activity is His112 rather than Lys58. pKa calculations of these amino acids, assessed through the 1 μs molecular dynamics simulation, confirm the hypothesis. Our findings highlight the ambiguity of destabilase catalytic residues identification and build foundations for further research of structure–activity relationship of isopeptidase activity as well as structure-based protein design for potential anticoagulant drug development.</p

    Data on 30-year stand dynamics in an old-growth broad-leaved forest in the Kaluzhskie Zaseki State Nature Reserve, Russia

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    The article provides primary data on repeated tree measurements collected during two censuses on a permanent sampling plot (440 m × 200 m) established in the old-growth polydominant broad-leaved forest in the Kaluzhskie Zaseki State Nature Reserve (centre of European Russia). The time span between the inventories was 30 years, and a total of 11 578 individuals of ten tree, one shrub species, and several undefined tree species of three known genera were registered. During the surveys, tree identity, stem diameter at breast height (DBH) of 1.3 m, and life status (alive or dead) were recorded for every tree individual with DBH ≥ 5 cm. Additional attributes were determined for some individuals. Field data were digitised and compiled into the PostgreSQL database. An accurate data quality assessment, validation, and cleaning (with documentation of changes) have been performed before data standardisation according to the Darwin Core standard. Standardised data were published through the GBIF repository. From 1986 to 1988, 9811 individuals were recorded within the initial census, including 3920 Corylus avellana individual shrubs. Corylus avellana shrubs were recorded without measuring DBH. From 2016 to 2018, 7658 stems were recorded in the recensus, including 3090 living trees marked during the initial census, and 1641 other living trees reaching the DBH of at least 5 cm. Corylus avellana was not included in the recensus. Thus, over 30 years, about 65% of living tree individuals have survived, but the total number of living trees has not changed considerably. The mean diameter of shade-intolerant tree species (Quercus robur, Fraxinus excelsior, Populus tremula, and Betula spp.) has increased the most remarkably during 30 years. For these species, the increase in average diameter, along with the decrease in numbers, is associated with the death of young trees, presumably due to low illumination under the canopy. Contrastingly, shade-tolerant tree species (Ulmus glabra, Tilia cordata, Acer platanoides) increased in number, while their mean diameter increased slightly or even decreased, that evidences the successful regeneration of these species under the canopy. These data are relevant for investigating forest ecology questions at spatiotemporal scales as a model of natural succession

    ORIENTAL JOURNAL OF CHEMISTRY Microstructure and Optical Properties of Composites Consisting of Nanoporous Stretched Polypropylene doped with Liquid Crystals and Quantum Dots at a High Concentration

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    ABSTRACT Unique properties of nanohybrid composites based on different types of porous polymer matrices doped with fluorescent nanoparticles (quantum dots, QDs) are determined by the combination of the mechanical properties of the host matrix (flexibility, chemical stability, etc.) and a high luminescence intensity and extreme stability of QDs. Here, we report on the preparation, optical and microstructural characterization of a nanoporous stretched polypropylene matrix embedded with CdSe/ZnS QDs as fluorescent dopants at a high concentration. The microstructure and optical properties of two types films based on QD-polymer composites and liquid crystals are described. The distribution of QDs in the composite films and their morphology was determined. The annealing of the nanoporous composite films leads to shrinking of the pores and encapsulation of QDs, which results in a domain-like structure. The resulting flexible, stable and highly luminescent materials may be applied to obtain the highly luminescent diodes, the light converter devices and the display systems

    Nucleoside Analogs and Perylene Derivatives Modulate Phase Separation of SARS-CoV-2 N Protein and Genomic RNA In Vitro

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    The life cycle of severe acute respiratory syndrome coronavirus 2 includes several steps that are supposedly mediated by liquid–liquid phase separation (LLPS) of the viral nucleocapsid protein (N) and genomic RNA. To facilitate the rational design of LLPS-targeting therapeutics, we modeled N-RNA biomolecular condensates in vitro and analyzed their sensitivity to several small-molecule antivirals. The model condensates were obtained and visualized under physiological conditions using an optimized RNA sequence enriched with N-binding motifs. The antivirals were selected based on their presumed ability to compete with RNA for specific N sites or interfere with non-specific pi–pi/cation–pi interactions. The set of antivirals included fleximers, 5′-norcarbocyclic nucleoside analogs, and perylene-harboring nucleoside analogs as well as non-nucleoside amphiphilic and hydrophobic perylene derivatives. Most of these antivirals enhanced the formation of N-RNA condensates. Hydrophobic perylene derivatives and 5′-norcarbocyclic derivatives caused up to 50-fold and 15-fold enhancement, respectively. Molecular modeling data argue that hydrophobic compounds do not hamper specific N-RNA interactions and may promote non-specific ones. These findings shed light on the determinants of potent small-molecule modulators of viral LLPS
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