Porous Structure of Powders Prepared with Heat Treatment of Gels from Tin (IV) and Antimony (III) Hydroxides

The effect of heat treatment on the parameters of the porous structure of powders in the system Sn(IV) Sb O is studied. It is established that xerogels of coprecipitated tin and antimony hydroxides dried at 360 K are microporous adsorbents containing particles of both crystalline and amorphous phases. During powder heat treatment there is formation of solid solutions based on tin dioxide and there is redistribution of the microporous structure into a mesoporous structure. This is accompanied by a reduction in specific surface and an increase in pore size.     

Silyl Modification of Biologically Active Compounds. 14. Organosilicon Lipid-like Derivatives of Hydroxyethyl Tetrahydro(iso)quinoline and Thiazole with Antitumour,Antibacterial and Antifungal Properties

Silicon - A series of novel lipid-like O- and N-(3-trimethylsilyl)propyl derivatives of N-(2-hydroxyethyl)-1,2,3,4-tetrahydroquinoline, -tetrahydroisoquinoline and...     

Asymmetric magnetization reversal of stripe-patterned exchange bias layer systems for controlled magnetic particle transport

Domain wall movement assisted transport of particles: exchange-biased samples with designed stripe-domains show strong stray fields and an asymmetric magnetization reversal. Using these characteristics superparamagnetic particles can be trapped and transported directly on the sample over large-scale areas. High particle velocities, small external fields, and automatically reduced particle clustering allow broad applicability of this transport method.     

Engineering of Ultra‐Hydrophobic Functional Coatings Using Controlled Aggregation of Bicomponent Core/Shell Janus Particles

The morphology and wetting properties of coatings prepared using fully‐ covered, mono‐ and bicomponent polymeric Janus particles are investigated and compared. The particles are adsorbed on silica wafers, which were preliminarily coated by thin layers of chemically grafted polymer. The fully‐covered particles form hexagonally packed layers with very hydrophobic wetting properties. In contrast, the Janus particles tend to form aggregates. This is possible due to their ability to self‐assemble and form hierarchical structured aggregates in dispersions. The deposition of these agglomerates on the substrate leads to the formation of hierarchical rough layers which possess a certain level of fractality. The obtained layers are either very hydrophobic or ultra‐hydrophobic, depending on the chemical structure of the polymers grafted to the Janus particles, on the nature of supported substrate, and on the level of aggregation of Janus particles into hierarchical structures. The obtained findings could be very important for design of novel materials with advanced properties.     

Synthesis of a Cytotoxic Amanitin for Biorthogonal Conjugation

Alpha‐amanitin is an exceedingly toxic, naturally occurring, bicyclic octapeptide that inhibits RNA polymerase and results in cellular and organismal death. Here we report the straightforward synthesis of an amanitin analogue that exhibited near‐native toxicity. A pendant alkyne was readily installed to enable copper‐catalyzed alkyne–azide cycloaddition (CuAAC) to azido‐rhodamine and two azide‐bearing versions of the RGD peptide. The fluorescent toxin analogue entered cells and provoked morphological changes consistent with cell death. The latter two conjugates are as toxic as the parent alkyne precursor, which demonstrates that conjugation does not diminish toxicity. In addition, we showed that toxicity depends on a single diastereomer of the unnatural amino acid, dihydroxyisoleucine (DHIle), at position 3. The convenient synthesis of a heptapeptide precursor now provides access to bioactive amanitin analogues that may be readily conjugated to biomolecules of interest.     

CRISPR/Cas9-Mediated Targeted DNA Integration: Rearrangements at the Junction of Plant and Plasmid DNA

Targeted DNA integration into known locations in the genome has potential advantages over the random insertional events typically achieved using conventional means of genetic modification. We studied the presence and extent of DNA rearrangements at the junction of plant and transgenic DNA in five lines of Arabidopsis thaliana suspension cells carrying a site-specific integration of target genes. Two types of templates were used to obtain knock-ins, differing in the presence or absence of flanking DNA homologous to the target site in the genome. For the targeted insertion, we selected the region of the histone H3.3 gene with a very high constitutive level of expression. Our studies showed that all five obtained knock-in cell lines have rearrangements at the borders of the integrated sequence. Significant rearrangements, about 100 or more bp from the side of the right flank, were found in all five plant lines. Reorganizations from the left flank at more than 17 bp were found in three out of five lines. The fact that rearrangements were detected for both variants of the knock-in template (with and without flanks) indicates that the presence of flanks does not affect the occurrence of mutations.     

Phase Formation in Sintering of Materials Based on Silicon Nitride with Li2CO3 and AlN Additives

We have studied the phase formation processes occurring in sintering of materials based on silicon nitride with lithium carbonate and aluminum nitride or Al powder additives. We have studied samples of different compositions that were sintered at 1450, 1550, and 1750°C under a nitrogen atmosphere. We have established that the phase composition depends on the sintering temperature, the composition of the starting charge, and also the amount and the nature of the Al-containing additives.     

Molecular Mechanisms of Changes in Homeostasis of the Dermal Extracellular Matrix: Both Involutional and Mediated by Ultraviolet Radiation

Skin aging is a multi-factorial process that affects nearly every aspect of skin biology and function. With age, an impairment of structures, quality characteristics, and functions of the dermal extracellular matrix (ECM) occurs in the skin, which leads to disrupted functioning of dermal fibroblasts (DFs), the main cells supporting morphofunctional organization of the skin. The DF functioning directly depends on the state of the surrounding collagen matrix (CM). The intact collagen matrix ensures proper adhesion and mechanical tension in DFs, which allows these cells to maintain collagen homeostasis while ECM correctly regulates cellular processes. When the integrity of CM is destroyed, mechanotransduction is disrupted, which is accompanied by impairment of DF functioning and destruction of collagen homeostasis, thereby contributing to the progression of aging processes in skin tissues. This article considers in detail the processes of skin aging and associated changes in the skin layers, as well as the mechanisms of these processes at the molecular level.