29 research outputs found

    ICEM2010-40186 MACROPOROUS CATALYSTS FOR HYDROTHERMAL OXIDATION OF METALLORGANIC COMPLEXES AT LIQUID RADIOACTIVE WASTE TREATMENT

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    ABSTRACT One of the main problems of liquid radioactive waste (LRW) management is concerned with treatment of decontamination waters containing organic ligands. The organic ligands like oxalic, citric and ethylenediaminetetraacetic acids form stable complexes with radionuclides which puts restrictions on application of many technologies of LRW management. One of the ways of destruction of metallorganic complexes consists in using the catalytic oxidation. However, the heterophase catalytic oxidation is rather problematic due to formation of metal oxides on the catalyst surface and calmatation of meso-and micropores. A possible solution of the above problem can be found in synthesis of macroporous catalysts for oxidation having a regular macroporous structure. The present paper describes the template synthesis of macroporous metalloxide catalysts performed with using siloxane-acrylate microemulsions as templates. The method for impregnation of precious metals (PM) particles into the template, which enables one to produce PM nanoparticles of a specific size and immobilize them in the porous structure of the synthesized metalloxide catalysts, is presented. A possible mechanism of the synthesis of macroporous catalysts is suggested and the comparison of the electronic and photoncorrelation spectroscopy results obtained at different stages of catalysts synthesis was conducted

    International Impact of COVID-19 on the Diagnosis of Heart Disease

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    BACKGROUND The coronavirus disease 2019 (COVID-19) pandemic has adversely affected diagnosis and treatment of noncommunicable diseases. Its effects on delivery of diagnostic care for cardiovascular disease, which remains the leading cause of death worldwide, have not been quantified. OBJECTIVES The study sought to assess COVID-19's impact on global cardiovascular diagnostic procedural volumes and safety practices. METHODS The International Atomic Energy Agency conducted a worldwide survey assessing alterations in cardiovascular procedure volumes and safety practices resulting from COVID-19. Noninvasive and invasive cardiac testing volumes were obtained from participating sites for March and April 2020 and compared with those from March 2019. Availability of personal protective equipment and pandemic-related testing practice changes were ascertained. RESULTS Surveys were submitted from 909 inpatient and outpatient centers performing cardiac diagnostic procedures, in 108 countries. Procedure volumes decreased 42% from March 2019 to March 2020, and 64% from March 2019 to April 2020. Transthoracic echocardiography decreased by 59%, transesophageal echocardiography 76%, and stress tests 78%, which varied between stress modalities. Coronary angiography (invasive or computed tomography) decreased 55% (p < 0.001 for each procedure). In multivariable regression, significantly greater reduction in procedures occurred for centers in countries with lower gross domestic product. Location in a low-income and lower-middle-income country was associated with an additional 22% reduction in cardiac procedures and less availability of personal protective equipment and telehealth. CONCLUSIONS COVID-19 was associated with a significant and abrupt reduction in cardiovascular diagnostic testing across the globe, especially affecting the world's economically challenged. Further study of cardiovascular outcomes and COVID-19-related changes in care delivery is warranted

    Impact of COVID-19 on cardiovascular testing in the United States versus the rest of the world

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    Objectives: This study sought to quantify and compare the decline in volumes of cardiovascular procedures between the United States and non-US institutions during the early phase of the coronavirus disease-2019 (COVID-19) pandemic. Background: The COVID-19 pandemic has disrupted the care of many non-COVID-19 illnesses. Reductions in diagnostic cardiovascular testing around the world have led to concerns over the implications of reduced testing for cardiovascular disease (CVD) morbidity and mortality. Methods: Data were submitted to the INCAPS-COVID (International Atomic Energy Agency Non-Invasive Cardiology Protocols Study of COVID-19), a multinational registry comprising 909 institutions in 108 countries (including 155 facilities in 40 U.S. states), assessing the impact of the COVID-19 pandemic on volumes of diagnostic cardiovascular procedures. Data were obtained for April 2020 and compared with volumes of baseline procedures from March 2019. We compared laboratory characteristics, practices, and procedure volumes between U.S. and non-U.S. facilities and between U.S. geographic regions and identified factors associated with volume reduction in the United States. Results: Reductions in the volumes of procedures in the United States were similar to those in non-U.S. facilities (68% vs. 63%, respectively; p = 0.237), although U.S. facilities reported greater reductions in invasive coronary angiography (69% vs. 53%, respectively; p < 0.001). Significantly more U.S. facilities reported increased use of telehealth and patient screening measures than non-U.S. facilities, such as temperature checks, symptom screenings, and COVID-19 testing. Reductions in volumes of procedures differed between U.S. regions, with larger declines observed in the Northeast (76%) and Midwest (74%) than in the South (62%) and West (44%). Prevalence of COVID-19, staff redeployments, outpatient centers, and urban centers were associated with greater reductions in volume in U.S. facilities in a multivariable analysis. Conclusions: We observed marked reductions in U.S. cardiovascular testing in the early phase of the pandemic and significant variability between U.S. regions. The association between reductions of volumes and COVID-19 prevalence in the United States highlighted the need for proactive efforts to maintain access to cardiovascular testing in areas most affected by outbreaks of COVID-19 infection

    Role of Interionic Interactions in Formation of Electronic and Dynamic Properties of Complex Fluorides

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    Available from VNTIC / VNTIC - Scientific & Technical Information Centre of RussiaSIGLERURussian Federatio

    Pedagogical Features of Training for Law Enforcement Activities in Terms of Collision with an Armed Enemy

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    За допомогою аналізу літератури з’ясовано особливості, а також установлено недоліки сучасної системи підготовки майбутніх правоохоронців. На основі проведених досліджень розроблено й теоретично обґрунтовано нову методику навчання майбутніх працівників міліції ефективної діяльності в умовах зіткнення із супротивником, озброєним холодною зброєю. Особливість методики – те, що формування спеціальних рухових умінь і навичок курсантів відбувається на базі засвоєння знань ситуаційних моделей рухової й мотиваційної поведінки супротивника, на основі яких правоохоронці зможуть будувати свої дії відповідно до міри загрози. Методикою передбачено акцентований розвиток фізичних і психологічних якостей, які означають перевагу в умовах озброєного зіткнення. By analysis of the literature, features and shortcomings of the current system established training future police officers were revealed. On the basis of researches was theoretically grounded latest techniques of training for the police in terms of efficient collision with the enemy, armed with knives. The feature of this method is that the formation of specific motor abilities and skills of students is based on situational learning models of motor and motivational behavior of the enemy against which police will be able to build their own actions according to the degree of threat. Methodology provides accentuated development of physical and psychological qualities that are preferred in armed clashes

    Fixation modes of gold(III) from solutions using cadmium(II) dithiocarbamates. Preparation, supramolecular structure and thermal behaviour of polynuclear and heteropolynuclear gold(III) complexes: Bis(N,N-dialkyldithiocarbamato-S,S′)gold(III) polychlorometallates, [Au(S2CNR2)2]nX (n=1: X=[AuCl4]−; n=2: X=[CdCl4]2−, [Cd2Cl6]2−)

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    Four novel heteropolynuclear and polynuclear complexes of the general formulae [Au(S2CNR2)2]2X (X = [CdCl4]2−, R = CH3 (1); X = [Cd2Cl6]2−, R = C3H7 (2)) and [Au(S2CNR2)2][AuCl4] (R = iso-C3H7 (3); R = iso-C4H9 (4)) were prepared using heterogeneous reactions between appropriate freshly precipitated binuclear cadmium(II) dialkyldithiocarbamates and AuCl3 in 2 M hydrochloric acid. The isolated complexes were studied by 13C CP/MAS NMR spectroscopy, single-crystal X-ray diffraction and simultaneous thermal analysis (STA) under an argon atmosphere. In all molecular structures (1–4), one of the gold atoms coordinates two dialkyldithiocarbamate ligands in the S,S′-bidentate mode, forming a square-planar coordination polygon [AuS4], while the other gold atom (in 3 and 4) has four neighbouring chlorine atoms [AuCl4]. At the supramolecular level, compounds 1 and 2 comprise binuclear cations, [Au2{S2CN(CH3)2}4]2+ and polynuclear chains, ([Au{S2CN(C3H7)2}2]+)n in a combination with [CdCl4]2− and [Cd2Cl6]2− anions, respectively. Unexpected structural distinctions at the supramolecular level were discovered for the chemically related compounds 3 and 4. In these ionic complexes, there are either cationic trinuclear formations, {[Au{S2CN(iso-C3H7)2}2]2[AuCl4]}+, or polynuclear chains, ([Au{S2CN(iso-C4H9)2}2]+)n, both combined with [AuCl4]− anions, in the structural basis of compounds 3 and 4, respectively

    A fixation mode of gold from solutions using heterogeneous reaction of cadmium dicyclohexyl dithiophosphate with H[AuCl4]. Structural and (13C, 31P) CP/MAS NMR studies and thermal behaviour of crystalline polymeric gold(I) dicyclohexyl dithiophosphate and bis(dicyclohexylthiophosphoryl) disulphide

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    Two novel compounds: polynuclear catena-poly[bis(μ3-O, O′-di-cyclo-hexyldithiophosphato-S,S,S′)digold(I)] (AuAu) (1) and crystalline bis(O,O′-di-cyclo-hexylthiophosphoryl)disulphide, (cyclo-C6H11O)2P(S)SS(S)P(O-cyclo-C 6H11)2 (2) were prepared using heterogeneous reaction between freshly precipitated binuclear cadmium(II) dithiophosphate (Dtph), [Cd2{S2P(O-cyclo-C6H11} 4] and H[AuCl4] in 2 M hydrochloric acid. The isolated compounds 1 and 2 (the fixation mode of gold from the solution and the oxidised form of Dtph groups, respectively) have been studied by means of single-crystal X-ray diffraction, 13C and 31P cross-polarisation/magic- angle-spinning (CP/MAS) NMR spectroscopy and simultaneous thermal analysis (STA). Centrosymmetric binuclear molecule of 1, [Au2{S 2P(O-cyclo-C6H11)2}2] comprises a pair of μ-bridging di-cyclo-hexyl Dtph ligands, linking two neighbouring gold atoms, and displays additional intramolecular aurophilic bond Au⋯Au. At the supramolecular level of structural self-organisation of complex 1, infinite polymeric zigzag chains arise due to pairs of the secondary bonds Au···S between neighbouring binuclear molecules. Centrosymmetric molecule of 2 displays two O,O′-di-cyclo- hexythiophosphoryl fragments, which are connected by the chemical bond S(1)S(1)a, and a planar zigzag array [SPSSPS] passing through the central part of the molecule. To characterise additionally the Dtph groups in both compounds 1 and 2, chemical shift anisotropy (CSA) parameters (δaniso and η) were calculated from spinning sideband manifolds in experimental 31P MAS NMR spectra. The thermal behaviour of complex 1 was studied using simultaneous thermal analysis (a combination of TG and DSC) under an argon atmosphere. The thermal behaviour displays stepwise mass loss, comprising thermal decompositions of the organic and inorganic parts of 1 with gold(I) dithio-meta-phosphate and reduced metallic gold as the intermediate and the final products, respectively

    Acidification of East Siberian Arctic Shelf waters through addition of freshwater and terrestrial carbon

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    Ocean acidification affects marine ecosystems and carbon cycling, and is considered a direct effect of anthropogenic carbon dioxide uptake from the atmosphere1–3 . Accumulation of atmospheric CO2 in ocean surface waters is predicted to make the ocean twice as acidic by the end of this century4 . The ArcticOcean is particularly sensitive to ocean acidification becausemoreCO2 candissolveincoldwater5,6 .Herewepresent observations of the chemical and physical characteristics of EastSiberianArctic Shelfwatersfrom1999,2000–2005,2008 and 2011, and find extreme aragonite undersaturation that reflects acidity levels in excess of those projected in this region for 2100. Dissolved inorganic carbon isotopic data and Markov chain Monte Carlo simulations of water sources using salinity andδ18 Odata suggest that the persistent acidification is driven by the degradation of terrestrial organic matter and discharge of Arctic river water with elevated CO2 concentrations, rather than by uptake of atmospheric CO2 . We suggest that East Siberian Arctic Shelf waters may become more acidic if thawing permafrost leads to enhanced terrestrial organic carbon inputs and if freshwater additions continue to increase, which may affect their efficiency as a source of CO2

    Crystalline O,O′-di-sec-butyl and O,O′-diethyl dithiophosphate platinum(II) complexes : synthesis, 13C and 31P CP/MAS NMR, single crystal X-ray diffraction studies and thermal behaviour

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    Crystalline bis(O,O'-di-sec-butyldithiophosphato)platinum(II) was prepared and studied by means of (13)C, (31)P CP/MAS NMR spectroscopy and single-crystal X-ray diffraction. The unit cell of the platinum(II) compound is comprised of one centrosymmetric mononuclear molecule [Pt{S(2)P(O-sec-C(4)H(9))(2)}(2)], in which the dithiophosphate groups display structural equivalence in both (31)P NMR and XRD data. A pair of the dithiophosphate ligands exhibit the same S,S'-bidentate chelating structural function and form two planar four-membered chelate rings, [PtS(2)P], in this molecule. The planar configuration of the [PtS(4)] chromophore in structure 1 is governed by the dsp(2)-hybrid state of platinum(II). The structural states of the dithiophosphate groups in two different samples of complex 1 (one crystallised from ethanol and the other one precipitated from an aqueous solution) are all characterised by almost rhombic (31)P chemical shift tensors. The observed essential dispersion of the (31)P NMR chemical shift is caused by a coexistence of six optical isomers of molecule 1. The thermal behaviour of this compound was studied by means of simultaneous thermal analysis (a combination of TG and DSC) under an argon atmosphere. The thermal behaviour shows that the mass of 1 is lost in three steps, involving successive thermal decompositions of the organic and inorganic parts of this compound with platinum(II) dithio-meta-phosphate and reduced metallic platinum as the intermediate and the final products, respectively. (C) 2011 Elsevier Ltd. All rights reserved
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