25 research outputs found

    Polytene chromosomes reflect functional organization of the Drosophila genome

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    Polytene chromosomes of Drosophila melanogaster are a convenient model for studying interphase chromosomes of eukaryotes. They are giant in size in comparison with diploid cell chromosomes and have a pattern of cross stripes resulting from the ordered chromatid arrangement. Each region of polytene chromosomes has a unique banding pattern. Using the model of four chromatin types that reveals domains of varying compaction degrees, we were able to correlate the physical and cytological maps of some polytene chromosome regions and to show the main properties of genetic and molecular organization of bands and interbands, that we describe in this review. On the molecular map of the genome, the interbands correspond to decompacted aquamarine chromatin and 5’ ends of ubiquitously active genes. Gray bands contain lazurite and malachite chromatin, intermediate in the level of compaction, and, mainly, coding parts of genes. Dense black transcriptionally inactive bands are enriched in ruby chromatin. Localization of several dozens of interbands on the genome molecular map allowed us to study in detail their architecture according to the data of whole genome projects. The distribution of proteins and regulatory elements of the genome in the promoter regions of genes localized in the interbands shows that these parts of interbands are probably responsible for the formation of open chromatin that is visualized in polytene chromosomes as interbands. Thus, the permanent genetic activity of interbands and gray bands and the inactivity of genes in black bands are the basis of the universal banding pattern in the chromosomes of all Drosophila tissues. The smallest fourth chromosome of Drosophila with an atypical protein composition of chromatin is a special case.  Using the model of four chromatin states and fluorescent in situ hybridization, its cytological map was refined and the genomic coordinates of all bands and interbands were determined. It was shown that, in spite of the peculiarities of this chromosome, its band organization in general corresponds to the rest of the genome. Extremely long genes of different Drosophila chromosomes do not fit the common scheme, since they can occupy a series of alternating bands and interbands (up to nine chromosomal structures) formed by parts of these genes

    Impact of plasma nanostructuring on the electrical properties of Cu(In,Ga)Se 2 films

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    In this work, the impact of the plasma treatment, during the formation of nanostructure arrays on the surface of the Cu(In,Ga)Se2 films on glass substrates, on the conductivity of the films both in the lateral direction and in the direction normal to the substrate surface was studied. The initial Cu(In,Ga)Se2 films with the Ga/(In + Ga) ratio in the range of 0.03–0.12 were obtained by thermal selenization process of stacked metallic precursors and by co-evaporation of all elements from various sources. The plasma treatment was carried out in a high-density low-pressure RF inductively coupled plasma reactor in argon plasma. The average ion energy was 200 eV, the processing time was 60 s. It is shown that the processes of the plasma nanostructuring of the Cu(In,Ga)Se2 film surface lead to the formation of a thin modified near-surface layer with a resistivity of 2–3 orders of magnitude less than for the bulk of the film

    Nanostructuring of the CIGS Films Surface by the Plasma Treatment with Low Ion Energy

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    We report on surface nanostructuring of Cu(In,Ga)Se2 (CIGS) films using inductively coupled argon plasma treatment with the ion energy of 25–30eV within 30–120s. The films were fabricated on glass substrates using the selenization method and had a polycrystalline structure. We demonstrate that the plasma treatment results in the formation of tip-shaped nanostructure arrays with the geometrical parameters controlled by the treatment duration. The features of the surface nanostructuring using low energy ions are discussed

    Investigation of thin films MgAl2O4, deposited on the Si substrates by vacuum thermal evaporation

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    The article presents data on the study of X-ray structural and microstructural characteristics of thin films of aluminum-magnesium spinel MgAl2O4 deposited on Si substrates by vacuum thermal evaporation. MgAl2O4 films have a polycrystalline rhombic structure. The values of the unit cell parameters of MgAl2O4 are calculated. Scanning electron and atomic force microscopy showed that MgAl2O4 films have a densely packed structure without cracks. Physical characteristics and good adhesion of MgAl2O4 thin films to silicon substrates indicate their possibility of using in devices of opto- and microelectronics

    Terbium photo-, cathodo- and X-ray luminescence in sol-gel derived films in porous anodic alumina

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    Photo-, cathodo-, and X-ray luminescence of terbium in sol-gel derived films, fabricated in porous anodic alumina is studied. The cell size of the fabricated film convertor of irradiation is about 250 nm. The methods of increase Tb luminescence under diverse excitation conditions are discussed. © 2012 CriMiCo

    Формирование иммобилизованного наноструктурированного диоксида титана, обладающего антибактериальными свойствами

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    Nanostructured titanium dioxide (TiO2) coatings were formed on rigid aluminum and flexible fiberglass substrates using the sol-gel method modified by adding nano- and submicron TiO2 particles to the sol. The use of sols with such particles leads to the formation of a rough coating of agglomerates of nano- and submicron particles bonded with sol-gel synthesized TiO2. The antibacterial activity of the coatings was confirmed under irradiation with visible light from an LED source for 120 minutes. The most activity was demonstrated by all samples in relation to Staphylococcus aureus.Наноструктурированные покрытия из диоксида титана (TiO2) сформированы на жестких алюминиевых и гибких стекловолоконных подложках золь-гель методом, модифицированным включением в золь нано- и субмикронных частиц TiO2. Добавление в золь таких частиц приводит к образованию шероховатого покрытия из агломератов нано- и субмикронных частиц, скрепленных золь-гель синтезированным диоксидом титана. Антибак териаль ная активность полученных покрытий подтверждена в условиях облучения видимым светом светодиодного ис точника в течение 120 мин. Наибольшая активность продемонстрирована всеми образцами в отношении золотистого стафилококка

    ADALIMUMAB DISCONTINUATION IN PATIENTS WITH RHEUMATOID ARTHRITIS AFTER ACHIEVING SUSTAINED REMISSION

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    Objective: to assess whether adalimumab (AD) can be gradually discontinued during continuous methotrexate (MTX) use in patients with early rheumatoid arthritis (ERA).Subjects and methods. Within the REMARCA (the Russian study of methotrexate and biological agents in early active arthritis) study, the investigators examined 20 patients (17 women and 3 men; median age, 51 [41.5; 56] years) with ERA (disease duration, 10 [5.5; 20] months; DAS28, 5.17 [4.37; 6.51]; 85% of the patients were seropositive for rheumatoid factor and 85% for anti-cyclic citrullinated peptide antibodies.Results and discussion. All the patients received subcutaneous MTX 25 mg/week. Twelve weeks after beginning therapy with MTX, due to its inefficiency, ADA was added according to the standard scheme. At week 24, the median DAS28 was 3.0 [1.65; 3.73]; 85% of the patients achieved remission or low disease activity. After 3 months of ADA therapy, high or moderate disease activity remained in 3 (15%) patients; median DAS28 was 4.4 [4.3; 6.1]; the drug was discontinued in them due to ineffective therapy. After 12-month follow-up, low DAS28 scores were observed in 5 (29.4%), DAS28 remission was in 12 (70.6%) of the 17 patients who continued ADA treatment; after 24 months, all the 17 patients were noted to have remission. After achieving sustained remission (≥ 6-month duration during ADA therapy), there was a carefully controlled reduction (titration) in the dose of ADA with its complete discontinuation, by maintaining remission at 36-month follow-up; the median DAS28 was 1.6 [1.4; 2.2]. During ADA treatment, one female patient developed pustular psoriasis and therefore the drug was discontinued at 24-month follow-up during the period of sustained remission. Other serious adverse events and tuberculosis cases were not recorded.Conclusion. Thus, the results of the study are indicative of the high clinical efficiency of the therapy. After ADA discontinuation, sustained remission can be maintained in patients with ERA and if they took biological agents early

    Inhomogeneous nanostructured honeycomb optical media for enhanced cathodo- and under-x-ray luminescence

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    Photo-, radio-, and pulse cathodoluminescence spectra from sol-gel derived titania, doped with strontium and terbium, deposited on porous anodic alumina (PAA) films are reported. The morphology and qualitative elemental depth distributions have been examined by transmission electron microscopy, scanning electron microscopy, and radio-frequency glow discharge optical emission spectroscopy. PAA films with pore and cell sizes ranging from 170 to 190 and 240 to 270 nm, respectively, have been generated on aluminum and monocrystalline silicon substrates followed by spin-on sol-gel derived coating with the subsequent thermal treatment. The resultant PAA surface is not coated with a continuous xerogel film; the xerogel is mainly distributed near the pore bases, leaving much of the pore volume unfilled. The xerogel/PAA structures reveal terbium-related luminescence under x-ray excitation and cathodoluminescence. The same xerogels generated on monocrystalline silicon revealed no cathode- or under-x-ray luminescence. Thus, PAA enhances strongly the cathode- and under x-ray luminescence from terbium and strontium-doped titania xerogels confined in the porous matrix. The fabricated structures are considered as a type of low-cost, thin-film convertor of x-rays, and cathode ray irradiation into visible light, with an average cell size of the convertor of about 250 nm. © 2012 American Institute of Physics
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