The combined effects of ionizing radiation and weightlessness on calcium and phosphorus content in the mineral fraction of the calcified tissues in the rat skeleton

Phosphorus and calcium content in the ash from skeletal bones (ribs, scapula, vertebra, and crus) of 30 rats exposed to ionizing radiation (800 rads) on the flight of the Kosmos 690 biosatellite was studied. A 10 percent decrease in ash content coefficient and 29 percent decrease in phosphorus content was found immediately after the flight, and a 9 percent decrease in phosphorus content persisted after 26 days of readaptation to terrestrial conditions

АТОМНО-ЭМИССИОННЫЙ АНАЛИЗ ВЫСОКОЧИСТОГО ОКСИДА ВОЛЬФРАМА И КРИСТАЛЛОВ ВОЛЬФРАМАТА КАДМИЯ C ИОНООБМЕННЫМ ОТДЕЛЕНИЕМ ВОЛЬФРАМА

Determination of impurities in tungsten oxide (WO3) and cadmium tungstate crystals CdWO4 (CWO) was performed by atomic emission spectrometry with a two-jet arc plasma (TJP-AES) after ion exchange tungsten separation. Tungsten metal obtained under reduction of WO3 and CWO by hydrogen was dissolved in 30 % hydrogen peroxide solution and passed through a cation exchange column. Impurities adsorbed on the column were eluted by nitric acid solution and evaporated on graphite powder. Element concentrations in graphite concentrate of impurities were determined by TJP-AES. The technique developed allows the determination of Ag, Al, Ba, Bi, Ca, Co, Cr, Cu, Dy, Eu, Fe, Ga, Gd, Mg, Mn, Ni, Sm, and Ti with detection limits in the range of 0.5-500 (WO3) and 0.3-350 (CWO) ng/g.Keywords: tungsten oxide, cadmium tungstate, reduction by hydrogen, ion exchange chromatography, two-jet arc plasma, impurities, atomic emission spectrometry.(Russian)DOI: http://dx.doi.org/10.15826/analitika.2013.17.1.006 N.P. Zaksas, L.N. Komissarova, P.S. Galkin, A.P. Zubareva Nikolaev Institute of Inorganic Chemistry SB RAS, Novosibirsk, Russian FederationОпределение примесей в оксиде вольфрама (WO3) и кристаллах вольфрамата кадмия CdWO4 (CWO) проводили методом атомно-эмиссионной спектрометрии с двухструйной дуговой плазмой (ДДП-АЭС) после ионообменного отделения вольфрама. Металлический вольфрам, полученный при восстановлении WO3 и CWO водородом, растворяли в 30 % растворе пероксида водорода и пропускали через катионообменную колонку. Примеси, адсорбированные на колонке, элюировали раствором азотной кислоты и упаривали на графитовый порошок. Содержание элементов в графитовом концентрате микропримесей определяли методом ДДП-АЭС. Разработанная методика позволяет определять Ag, Al, Ba, Bi, Ca, Co, Cr, Cu, Dy, Eu, Fe, Ga, Gd, Mg, Mn, Ni, Sm и Ti с пределами обнаружения 0.5-500 (WO3) и 0.3-350 (CWO) нг/г.Ключевые слова: оксид вольфрама, вольфрамат кадмия, восстановление водородом, ионообменная хроматография, двухструйная дуговая плазма, примеси, атомно-эмиссионный анализ.DOI: http://dx.doi.org/10.15826/analitika.2013.17.1.00

The balance of elements in the system “Luvic Chernozems – agricultural plants” on the Plavsk upland (Tula region of Russia)

To assess the transfer of macro (K, P, S, Mg, Ca, as well as Si, Na, Fe, Al, Mn and Ti) and microelements (Zn, Ba, Cu, Sr, Mo, as well as As, Zr, Pb, Co, Ni, V and Cr) from Luvic Chernozems (Aric, Loamic, Pachic) into agricultural plants, we studied the inventories of chemical elements in three agrocenoses (wheat, soybean, Galega orientalis Lam. and Bromopsis inermis Leyss grass mixtures) from the Plavsk upland (Tula Region). This territory is subjected to intensive industrial and agricultural impacts: it is 40 km away from the town of Shchekino with a nitrogen fertilizer plant and a thermal power plant, 60 km away from Tula with large metallurgical enterprises, 70 km away from the town of Novomoskovsk with several chemical enterprises and state district power plant. In soils, the total content of elements was determined by the X-ray fluorescence spectrometry. The elemental composition of plants after autoclave decomposition with a mixture of concentrated nitric acid and hydrogen peroxide and the content of the bioavailable fraction (extracted by an ammonium acetate buffer with pH 4.8) of elements in soil were estimated by the atomic emission spectrometry with inductively coupled plasma. In topsoil (a 10-cm layer), maximal inventories are typical for total Si (40 ± 4 kg/m2), Al (7.0 ± 0.8 kg/m2) and Fe (3.4 ± 0.3 kg/m2) and for bioavailable Ca (570 ± 48 g/m2), Mg (43 ± 4 g/m2), K (22 ± 6 g/m2). In plants, the main inventories (g/m2) of K, P, S, Mg, Si, Mn, Zn, Ba, Cu, Mo occur in the above ground phytomass. The most effectively plants assimilate bioavailable fractions of K, P, Ti, Mo, As, Zr, V. Based on the resource method for soil quality assessment, the studied Chernozems are characterized by a low level of Ni contamination, a moderate supply of bioavailable K with a lack of bioavailable P

Risks associated with the ethical aspects of conducting clinical trials

Conducting of clinical trials is closely associated with the ethical justification, with ensuring the rights and safety of the subjects participating in them. Only through trials, it becomes possible to obtain reliable data for the inclusion of new drugs in practice, which are designed to save millions of lives. In the constantly developing field of clinical research, science does not stand still and it becomes necessary to conduct more and more new research: pediatric, geriatric, biomedical products and research involving acute social problems, and of course they all involve certain risks during their implementation. The question of the ethics of conducting research in the context of the COVID-19 pandemic is very relevant at the moment, when it is necessary to make quick decisions in the interests of all mankind, assessing all possible risks that they may entail

Variability of Hot Supergiant IRAS 19336-0400 in the Early Phase of its Planetary Nebula Ionization

We present photoelectric and spectral observations of a hot candidate proto-planetary nebula - early B-type supergiant with emission lines in spectrum - IRAS 19336-0400. The light and color curves display fast irregular brightness variations with maximum amplitudes Delta V=0.30 mag, Delta B=0.35 mag, Delta U=0.40 mag and color-brightness correlations. By the variability characteristics IRAS 19336-0400 appears similar to other hot proto-planetary nebulae. Based on low-resolution spectra in the range lambda 4000-7500 A we have derived absolute intensities of the emission lines H_alpha, H_beta, H_gamma, [SII], [NII], physical conditions in gaseous nebula: n_e=10^4 cm^{-3}, T_e=7000 \pm 1000 K. The emission line H_alpha, H_beta equivalent widths are found to be considerably variable and related to light changes. By UBV-photometry and spectroscopy the color excess has been estimated: E_{B-V}=0.50-0.54. Joint photometric and spectral data analysis allows us to assume that the star variability is caused by stellar wind variations.Comment: 11 pages, 6 figures, 2 tables, accepted for publication in Pis'ma Astron. Zh. (Astronomy Letters

Spectrum of mutations and their phenotypic manifestations in children and adults with long QT syndrome

Aim. To determine the spectrum of mutations in the genes responsible for the long QT syndrome (LQTS) and study their phenotypic manifestations in patients with LQTS in different age groups.Materials and methods. The study included 35 unrelated probands with a clinical diagnosis of LQTS: 23 adults (8 men) and 12 children (9 boys). There were following clinical features: syncope — 54%, positive family history for SCD — 29%, implanted cardioverter defibrillator (ICD) — 46%. All participants underwent 12-lead electrocardiography (ECG), 24-hour Holter monitoring, genealogical analysis, echocardiography and cardiac MRI. The genetic study was performed by nextgeneration sequencing (NGS) using the MiSeq system (Illumina). The quantitative comparison of two unrelated groups was carried out using the nonparametric MannWhitney U-test. The differences were considered significant at p<0,05.Results. In the examined group of 35 probands, 23 genetic variants of pathogenicity class IV and V (hereinafter referred to as) were identified. The molecular genetic variant of the disease was verified in 66% of probands. At the same time, the detection of mutations in the group with early manifestation (children) was significantly higher: 83% (10 out of 12 children) vs 57% in adults (13 out of 23). Rare genetic variants of uncertain significance (VUS, class III pathogenicity) were detected in 4 probands (11%). In the groups of children and adults with LQT1, LQT2 and LQT3, the sex distribution deviated from the 1:1 ratio. Among children, two-thirds were boys, among adults — the same proportion was represented by women. Disease manifestation time, QTc duration and adverse events risk depended on the genetic type of LQTS, intragenic localization of mutations and sex. In children, all 4 missense mutations in the KCNQ1 gene were located in transmembrane domain, and in adults, 4 mutations were in the transmembrane domain and three — in the C-terminal domain of the protein. LQT1 in boys was characterized by early manifestation, while QTc did not exceed 500 ms and there were no adverse outcomes. Two women out of 7 adults with LQT1 with mutations in the transmembrane domain had na ICD (QTc >520 ms). All patients with LQT2 (4 children, 4 adults) had QTc >500 ms. At the same time, 2 children and 3 women had an ICD. LQT3 was diagnosed only in the children subgroup (2 boys, with QTc of 510 ms and QTc of 610 ms); one of them died suddenly despite beta-blocker therapy. Four adult patients, carriers of class III pathogenicity variants, had QTc <500 ms and delayed disease manifestation (after 30 years). Three of them had episodes of clinical death with subsequent resuscitation and implantation of cardioverter defibrillator.Conclusion. The average diagnostic efficiency of mutation identification using NGS in patients with clinically manifest LQTS was 66%. At the same time, mutations were more common in the children’s group. In genotype-positive probands, the risk of adverse outcomes correlated with sex, age and the genetic variant of disease. The greatest number of adverse outcomes was observed in carriers of mutations in both KCNH2 (LQT2) and SCN5A (LQT3) genes. Variants with unknown clinical significance were identified in 4 probands (11%), which potentially allowed to confirm the diagnosis after functional tests