Formation of nanostructured state in LaBGeO₅ monolithic glass using pulsed magnetic fields

Using the methods of transmission electron microscopy, X-ray structure analysis and thermal differential analysis, it has been discovered that the pulsed magnetic field (PMF) intensifies homogeneous crystallization in LaBGeO₅-glass system, promotes homogenization of crystalline phase distribution inside the bulk of glass matrix. A possibility of obtaining the volume nanostructured state in LaBGeO₅-glass due to application of PMF has been suggested and experimentally grounded

Synthesis of carbon nanomaterials by means of microwave-assisted catalytic pyrolysis of cellulose

The growing demand for carbon nanotubes, which are typical representatives of the class of carbon nanomaterials and have unique physical and chemical properties, necessitates the search for available and renewable hydrocarbon resources for their production and development of an energy-efficient and a highly productive synthesis method. The prospects of using lignocellulosic biomass and its wastes as a carbon source for the synthesis of carbon nanotubes by means of microwave catalytic pyrolysis are considered. The expediency of research in this direction is emphasized. It is noted that one of the parameters responsible for the process of pyrolytic synthesis of carbon nanotubes is the concentration of microwave radiation absorber, which determines pyrolysis temperature. The effect of changing the concentration of microwave absorber in reaction mixture on the catalytic synthesis of multi-walled carbon nanotubes during microwave pyrolysis of cellulose has been studied. It is shown that a change in the microwave acceptor content from 10 to 30% is accompanied by an increase in the concentration of multi-walled carbon nanotubes of disordered morphology in reaction mixture. A two-stage pyrolysis-synthesis process is suggested. The results of transmission electron microscopy and X-ray phase analysis of the obtained products are considered

Phase transformations in the synthesis of La₀.₇Sr₀.₃MnO₃ nanopowders

La₀.₇Sr₀.₃MnO₃ nanopowder has been obtained by co-precipitation of the metal salts out of solution using sodium carbonate. The nanopowder synthesized contains two morphologically different particle types of 40 and 100 to 200 nm size. Using X-ray diffraction and transmission electron microscopy, phase transformations of the synthesis products have been studied within temperature range of 300 to 900°C. The nanoparticle formation genesis is traced and reasons for bimodal size distribution thereof are explained.Нанопорошок La₀.₇Sr₀.₃MnO₃ получен методом совместного осаждения растворов солей металлов карбонатом натрия. Синтезированный нанопорошок состоит из двух типов частиц с размерами 40 и 100-200 нм и разной морфологической формой. Методами рентгеноструктурного анализа и просвечивающей электронной микроскопии исследовались фазовые превращения продуктов синтеза в интервале температур 300-900°С. Прослежен генезис образования наночастиц и объяснены причины их бимодального распределения по размерам.Нанопорошок La₀.₇Sr₀.₃MnO₃ одержано методом сумісного осадження розчинів солей металів карбонатом натрію. Синтезований нанопорошок складається з двох типів частинок із розмірами 40 та 100-200 нм і різною морфологією. Методами рентгеноструктурного аналізу і просвічуючої електронної мікроскопії досліджено фазові перетворення продуктів синтезу в інтервалі температур 300-900°С. Простежено генезис утворення наночастинок і пояснено причини їх бімодального розподілу за розмірами

X-ray photoelectron spectroscopy of nanopowders of ZrO₂-Y₂O₃-Cr₂O₃ compounds

The X-ray photoelectron spectroscopy investigation of doped zirconium dioxide nanopowders of ZrO₂ + 3 mol.% Y₂O₃ + 0.5 % Cr₂03, ZrO₂ + 0.5% Cr₂O₃ and ZrO₂ + 3 mol.% Y₂O₃ compositions has been carried out in order to obtain information about surface states of the nanoparticles. Samples of all compositions are nonstoichiometric and include four states of zirconium atoms: Zr⁴⁺(O²⁻, Zr⁴⁺(OH), Zr³⁺, and Zr²⁺. Although initial states of samples doped with yttrium and chromium and with yttrium only differ slightly from one another, after calcination at 600 °C in air for 1 h, intensity of component corresponding to Zr-OH bond in case of Y-doping decreased by 58% and in case of Y and Cr doping by 27% only. This fact shows that doping with chromium oxide slows down depiction of OH groups and explains nanopowders crystallization process delay

Expression of peroxiredoxin 1, 2, 3, and 6 genes in cancer cells during drug resistance formation

We studied the expression of peroxiredoxin genes (PRDX1, PRDX2, PRDX3, and PRDX6) in human erythroleukemia K652, human breast carcinoma MCF-7, and human ovarian carcinoma SKOV-3 cells during cisplatin resistance development. It was found that drug resistance formation was accompanied by a significant increase in the expression of PRDX1, PRDX2, PRDX3, PRDX6 genes in all cancer cell strains, which confirms the important contribution of redox-dependent mechanisms into the development of cisplatin resistance of cancer cells. © 2012 Springer Science+Business Media New York

Graphite oxide: peculiarities of investigation of this material by physical methods

It is shown by physical methods that the preliminary preparation of samples affects the structure and properties of graphite oxide and partially reduced graphite oxide. The graphite oxide drying technique as the last synthesis stage determines its morphology and structural properties. At drying by sublimation method, the state of graphite oxide in aqueous suspension before the beginning of the process of self-ordering of its sheets is fixed, the data of X-ray diffraction analysis testifies its X-ray amorphous state, the dried graphite oxide appearance is a light yellow powder. Drying of graphite oxide aqueous suspensions at temperatures above room temperature is accompanied by the ordering of the graphite oxide structure under the action of the surface tension and Van der Waals forces with the dark brown film formation. It is shown by scanning and transmission microscopy methods that the method of separation of partially reduced graphite oxide from glass substrates, on which the product is dried, can lead to the formation of wrinkled or roll-shaped structures. When graphite oxide is examined by transmission electron microscopy, even a short exposure to ultrasound (used in the conventional method of depositing the material on a copper grid prior to examination) results in wrinkling and partial curling of the edges of graphite oxide nanoparticles. Mechanical grinding of graphite oxide leads to disordered graphite oxide structure and to the interplanar spacing increase

Expression of peroxiredoxin 1, 2, 3, and 6 genes in cancer cells during drug resistance formation

We studied the expression of peroxiredoxin genes (PRDX1, PRDX2, PRDX3, and PRDX6) in human erythroleukemia K652, human breast carcinoma MCF-7, and human ovarian carcinoma SKOV-3 cells during cisplatin resistance development. It was found that drug resistance formation was accompanied by a significant increase in the expression of PRDX1, PRDX2, PRDX3, PRDX6 genes in all cancer cell strains, which confirms the important contribution of redox-dependent mechanisms into the development of cisplatin resistance of cancer cells. © 2012 Springer Science+Business Media New York

Slow fluorescence induction and productivity of barley treated with a supercritical fluid extract of amaranth

Treatment of barley plants with a supercritical fluid extract of amaranth led to an increase in parameter (FM - FT)/FT of the leaf slow fluorescence induction curve. Barley treated with the extract showed higher productivity and better crop indices.ОРИГИНАЛЬНАЯ ВЕРСИЯ: МЕДЛЕННАЯ ИНДУКЦИЯ ФЛУОРЕСЦЕНЦИИ И ПРОДУКТИВНОСТЬ ЯЧМЕНЯ, ОБРАБОТАННОГО CВЕРХКРИТИЧЕСКИМ ФЛЮИДНЫМ ЭКСТРАКТОМ АМАРАНТА / Каpаваев В.А., Гунаp Л.Э., Мякиньков А.Г. [и др.] // Биофизика. 2012. Т. 57. № 4. С. 662-66

МЕДЛЕННАЯ ИНДУКЦИЯ ФЛУОРЕСЦЕНЦИИ И ПРОДУКТИВНОСТЬ ЯЧМЕНЯ, ОБРАБОТАННОГО CВЕРХКРИТИЧЕСКИМ ФЛЮИДНЫМ ЭКСТРАКТОМ АМАРАНТА

ПЕРЕВОДНАЯ ВЕРСИЯ: SLOW FLUORESCENCE INDUCTION AND PRODUCTIVITY OF BARLEY TREATED WITH A SUPERCRITICAL FLUID EXTRACT OF AMARANTH / Karavaev V.A., Glazunova S.A., Levykina I.P. [и др.] // Biophysics. 2012. Т. 57. № 4. С. 502-503Показано, что обpаботка pаcтений ячменя cвеpxкpитичеcким флюидным экcтpактом амаpанта пpиводит к увеличению паpаметpа (FM - FT)/FT медленной индукции флуоpеcценции лиcта. У обpаботанного ячменя наблюдалоcь увеличение уpожайноcти и оcновныx показателей cтpуктуpы уpожая