628 research outputs found

    Surface reactions with participation of oxides of molybdenum and tungsten: the influence of external factors

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    This work is a continuation of the article “Surface reactions with participation of oxides of molybdenum and tungsten”, published in the previous issue of the journal. The influence of the electric field and the pressure of oxygen in the gas phase on the rate of surface reactions for the synthesis of molybdates of manganese and copper were investigated. It’s found that for the synthesis reaction of molybdate of copper the nature of the dependency of the rate of synthesis and rate of surface reactions from the external parameters are the same, indicating the crucial contribution of surface diffusion to the reactive mass transfer. For the synthesis reaction of molybdate of manganese the dependences of the rate of synthesis and of rate of surface reactions by external parameters differ, indicating that for this reaction, surface diffusion isn’t the main mechanism of mass transfer

    Analysis of the placental tissue transcriptome of normal and preeclampsia complicated pregnancies

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    Preeclampsia is one of the most severe gestational complications which is one of the leading causes of maternal and perinatal morbidity and mortality. A growth in the incidence of severe and combined forms of the pathology has been observed in recent years. According to modern concepts, inadequate cytotrophoblast invasion into the spiral arteries of the uterus and development of the ischemia-reperfusion syndrome in the placental tissue play the leading role in the development of preeclampsia, which is characterized by multipleorgan failure. In this regard, our work was aimed at studying the patterns of placental tissue transcriptome that are specific to females with PE and with physiological pregnancy, as well as identifying the potential promising biomarkers and molecular mechanisms of this pathology. We have identified 63 genes whose expression proved to differ significantly in the placental tissue of females with PE and with physiological pregnancy. A cluster of differentially expressed genes (DEG) whose expression level is increased in patients with preeclampsia includes not only the known candidate genes that have been identified in many other genome-wide studies (e.g., LEP, BHLHB2, SIGLEC6, RDH13, BCL6), but also new genes (ANKRD37, SYDE1, CYBA, ITGB2, etc.), which can be considered as new biological markers of preeclampsia and are of further interest. The results of a functional annotation of DEG show that the development of preeclampsia may be related to a stress response, immune processes, the regulation of cell-cell interactions, intracellular signaling cascades, etc. In addition, the features of the differential gene expression depending on preeclampsia severity were revealed. We have found evidence of the important role of the molecular mechanisms responsible for the failure of immunological tolerance and initiation of the pro-inflammatory cascade in the development of severe preeclampsia. The results obtained elaborate the concept of the pathophysiology of preeclampsia and contain the information necessary to work out measures for targeted therapy of this disease.

    Microbial Enrichment of a Novel Growing Substrate and its Effect on Plant Growth

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    The quality of torrefied grass fibers (TGF) as a new potting soil ingredient was tested in a greenhouse experiment. TGF was colonized with previously selected microorganisms. Four colonization treatments were compared: (1) no inoculants, (2) the fungus Coniochaeta ligniaria F/TGF15 alone, (3) the fungus followed by inoculation with two selected bacteria, and (4) the fungus with seven selected bacteria. Cultivation-based and DNA-based methods, i.e., PCR-DGGE and BOX-PCR, were applied to assess the bacterial and fungal communities established in the TGF. Although colonization was not performed under sterile conditions, all inoculated strains were recovered from TGF up to 26 days incubation. Stable fungal and bacterial populations of 108 and 109 CFU/g TGF, respectively, were reached. As a side effect of the torrefaction process that aimed at the chemical stabilization of grass fibers, potentially phytotoxic compounds were generated. These phytotoxic compounds were cold-extracted from the fibers and analyzed by gas chromatography mass spectrometry. Four of 15 target compounds that had previously been found in the extract of TGF were encountered, namely phenol, 2-methoxyphenol, benzopyran-2-one, and tetrahydro-5,6,7,7a-benzofuranone. The concentration of these compounds decreased significantly during incubation. The colonized TGF was mixed with peat (P) in a range of 100%:0%, 50%:50%, 20%:80%, and 0%:100% TGF/P (w/w), respectively, to assess suitability for plant growth. Germination of tomato seeds was assessed three times, i.e., with inoculated TGF that had been incubated for 12, 21, and 26 days. In these tests, 90–100% of the seeds germinated in 50%:50% and 20%:80% TGF/P, whereas on average only 50% of the seeds germinated in pure TGF. Germination was not improved by the microbial inoculants. However, plant fresh weight as well as leaf area of 28-day-old tomato plants were significantly increased in all treatments where C. ligniaria F/TGF15 was inoculated compared to the control treatment without microbial inoculants. Colonization with C. ligniaria also protected the substrate from uncontrolled colonization by other fungi. The excellent colonization of TGF by the selected plant-health promoting bacteria in combination with the fungus C. ligniaria offers the possibility to create disease suppressive substrate, meanwhile replacing 20% to 50% of peat in potting soil by TGF

    Synthesis of a Sterically Encumbered Pincer Au(III)−OH Complex

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    We report the synthesis and crystallographic characterization of a novel Au(III)−OH complex featuring a N^N^N-pincer ligand. Reactivity studies towards oxygen atom transfer (OAT), a type of reactivity previously reported for a Au(III)−OH complex, indicate that this complex provides both a sterically encumbered Au atom and a sterically poorly accessible OH group leading to no reactivity with a series of phosphines. The steric encumbrance sets this example apart from the known examples of Au(III)−OH (pincer) complexes, which commonly feature planar ligands that provide little control over steric accessibility of the Au and O atoms in these complexes. Implications for the mechanism of OAT from Au−OH complexes are briefly discussed

    Molecular mechanisms of autism as a form of synaptic dysfunction

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    Autism spectrum disorders are a separate group of defects with a very high genetic component. Genetic screening has identified hundreds of mutations and other genetic variations associated with autism, and bioinformatic analysis of signaling pathways and gene networks has led to understanding that many of these mutational changes are involved in the functioning of synapses. A synapse is a site of electrochemical communication between neurons and an essential subunit for learning and memory. Interneuronal communicative relationships are plastic. The most prominent forms of synaptic plasticity are accompanied by changes in protein biosynthesis, both in neuron body and in dendrites. Protein biosynthesis or translation is a carefully regulated process, with a central role played by mTOR (mammalian or mechanistic target of rapamycin). Normally mTOR-regulated translation is slightly inhibited, and in most cases mutational damage to at least one of the links of the mTOR signaling pathway, increases translation and leads to impaired synaptic plasticity and behavior. Deregulation of the local translation in dendrites is connected with the following monogenic autism spectrum disorders: neurofibromatosis type 1, Noonan syndrome, Costello syndrome, Cowden syndrome, tuberous sclerosis, fragile X chromosome, syndrome, and Rett syndrome. The review considers the most important mutations leading to monogenic autism, as well as the possibility of a mechanism-based treatment of certain disorders of the autism spectrum

    Значение исследования семейного анамнеза при антифосфолипидном синдроме

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    The investigation of 82 families of patients with antiphospholipid syndrome (APS) was performed. APS was diagnosed in 1st-degree relatives and woman more frequently. Minor features of APS were revealed in half of relatives, lupus anticoagulant (LA) — in a third of them. If person has APS in family anamnesis, minor features of APS or (and) LA, pre-APS can be diagnosed and primary prevention of thrombosis can be conducted.Проведено исследование 82 семей больных антифосфолипидным синдромом (АФС). АФС чаще диагностировался у родственников первой степени родства и у женщин. Малые проявления АФС обнаружены у половины родственников, волчаночный антикоагулянт (ВА) - у трети из них. При наличии АФС в семейном анамнезе, малых проявлений АФС и (или) ВА возможно выделение пре-АФС и проведение первичной профилактики тромбозов

    Polymeric Coatings Composition Based on Modified Oligopiperylene Styrene Binders with Galvanic Sludge as a Filler

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    Abstract The possibility of development of new coating materials based on oligopiperylene styrene modified with alkoxysilane and galvanic sludge as a pigment-filler is presented in this article. The nanostructure of the coating surface and the influence of the composition and nature of the components of paint and varnish materials on its property are studied. These materials are intended for protection buildings from the effects of adverse factors

    Spectroscopic Manifestations and Implications for Catalysis of Quasi-d<sup>10</sup> Configurations in Formal Gold(III) Complexes.

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    Several gold +I and +III complexes are investigated computationally and spectroscopically, focusing on the d-configuration and physical oxidation state of the metal center. Density functional theory calculations reveal the non-negligible electron-sharing covalent character of the metal-to-ligand σ-bonding framework. The bonding of gold(III) is shown to be isoelectronic to the formal CuIII complex [Cu(CF3)4]1- , in which the metal center tries to populate its formally unoccupied 3dx2-y2 orbital via σ-bonding, leading to a reduced d10 CuI description. However, Au L3-edge X-ray absorption spectroscopy reveals excitation into the d-orbital of the AuIII species is still possible, showing that a genuine d10 configuration is not achieved. We also find an increased electron-sharing nature of the σ-bonds in the AuI species, relative to their AgI and CuI analogues, due to the low-lying 6s orbital. We propose that gold +I and +III complexes form similar bonds with substrates, owing primarily to participation of the 5dx2-y2 or 6s orbital, respectively, in bonding, indicating why AuI and AuIII complexes often have similar reactivity

    Ethylene and expansin biosynthesis related genes polymorphism in local apple (Malus domestica Borkh.) cultivars from VIR Collection of plant genetic resources

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    At Pushkin and Pavlovsk Laboratories of the N.I. Vavilov All-Russian Institute of Plant Genetic Resources (VIR) a diverse collec tion of local apple cultivars is maintained. Some of the cultivars are widely used in breeding programs for their ecological plasticity, increased adaptation to abiotic stress and disease resistance, still there have been no large-scale studies of these local cultivars for fruit storage ability. Fruit softening during storage is an important problem for apple production. Retention of desirable firmness after prolonged storage is one of the key requirements for new apple cultivars. Expansin and ethy lene biosynthesis related genes are known to be involved in control of fruit softening in apple, and gene specific molecular markers have been reported. In this study the polymorphism and allelic configuration of ethylene and expansin biosynthesis related genes Md-ACS1, Md-ACO1 and Md-Exp7 involved in control of fruit softening in 87 local apple cultivars from VIR Collection of Plant Genetic Resources were analyzed. PCR markers Md-ACS1, Md-ACO1 and SSR-marker Md-Exp7 were used in the study. The allele frequencies in the collection generally coincided with the data from previous studies. Md-ACS1 allele 2 associated with reduced ethylene production was found only in three local cultivars, while all the studied local cultivars were heterozygous for the Md-ACO1 locus, as well as most modern Russian apple cultivars. Half of the studied local cultivars were heterozygous for Md-Exp7 (198 : 202). Thirteen local cultivars with rare Md-Exp7 alleles (206, 210 and 212) were detected. No association was found between the Md-Exp7 genotype and the cultivars’ maturation time. The obtained results can be used for additional evaluation of the cultivars’ potential for breeding
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