39 research outputs found

    Size fractionation of trace elements in the surface water and groundwater of the Ganjiang River and Xiushui River basins, China

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    The research of trace element behaviour and size fractionation is significant to understand the processes in the water-rock system. Moreover, the aqueous speciation of trace elements is strongly related to their distribution and toxicity. In this research, trace elements behaviour and their size fractionation are investigated in the natural water (the surface water and shallow groundwater) of the Ganjiang River and Xiushui River basins. Trace element concentrations were measured by ICP-MS. The authors estimated the size fractionation of the trace elements between suspended forms (>0.45 [mu]m) and dissolved fractions, which included truly dissolved (1 kDa) and colloidal particles (0.45 [mu]m-1 kDa)), after filtration through a 0.45 [mu]m acetate cellulose membrane filter. The distinct features of the trace element size fractionation were identified. The size fractionation of the trace elements under different conditions (in the surface water and shallow groundwater) was studied

    Semi-Wild Population of Kulans in the Bukhara Breeding Centre and Their Co-Habitation with Przewalski’s Horses

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    Asiatic wild asses and Przewalski\u27s horses initially inhabited steppe, semi-desert and desert areas, but Przewalski\u27s horses became extinct in the wild, and kulans are under threat of disappearance. The Bukhara Breeding Centre (Uzbekistan) was created in 1976 for conservation and reintroduction of wild ungulate species. In 1977-1978, five kulans (two males and three females) from Barsa-Kelmes Island on the Aral lake were introduced to the reserve. The group increased to 25-30 animals in 1995-1998, when five Przewalski\u27s horses from Moscow and St. Petersburg zoos were introduced to the same territory. We analyzed the home ranges, preferred habitats and social interactions of these closely related species during 1995-1999 by season and group composition. Horses and kulans each formed a reproductive group and a secondary bachelor group. The home range of the secondary group in both species was larger then that of the reproductive group and seemed to be less dependent on watering places. Kulans and Przewalski\u27s horses demonstrated different strategies of habitat use. They can share one area without serious conflicts, avoiding competition by the temporal differentiation in the usage of key sites

    Program-targeted regulation of the regional consumer market

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    The primary strategic tasks for development of the Russian Federation and its regions are the increase of the level and quality of life and increase of the share of the middle class on the basis of modernization and restructuring the economy, the growth of entrepreneurial and innovative activities and competitiveness. For the solution of these problems the development of the consumer market should play an important role, performing important economic and social functions. In the article the results of the study of scientific views of foreign and national scientists on the category "consumer market" are shown from the perspective of the principle of historical and logical unity, theoretical and conceptual approaches to its formation and development are systematized, positive trends in its development are revealed; negative social consequences associated with excessive consumption growth and the formation of a consumer society are proved (violation of the ecological balance, people health aggravation, change of people’s attitudes). The necessity of government regulation of the consumer market on all the levels is proved (federal, regional and municipal) based on the prospective vision and its development strategy in the context of globalization, Russia's accession to WTO and the implementation of the sanctions against Russia by the United States, several European and Asian countries. As a methodological approach to solve identified problems on the regional level it is proposed to use the program-targeted regulation of the consumer market, which allows connecting the objectives with the resources and deadlines for their implementation by particular executives. Its use also allows authorities to develop alternative solutions for the tasks on the basis of the justification of priorities in the development of the consumer market and assessment of the risks associated with the implementation of program activities.peer-reviewe

    Facile one-pot synthesis of diaryliodonium salts from arenes and aryl iodides with oxone

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    A straightforward synthesis of diaryliodonium salts is achieved by using Oxone as the stoichiometric oxidant. Slow addition is the key to obtaining good yields and purities of the reaction products, which are highly useful reagents in many different areas of organic synthesis

    2-Iodoxybenzoic acid ditriflate: the most powerful hypervalent iodine(v) oxidant

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    A ditriflate derivative of 2-iodoxybenzoic acid (IBX) was prepared by the reaction of IBX with trifluoromethanesulfonic acid and characterized by single crystal X-ray crystallography. IBX-ditriflate is the most powerful oxidant in a series of structurally similar IBX derivatives which is best illustrated by its ability to readily oxidize hydrocarbons and the oxidation resistant polyfluoroalcohols

    Vocal group signatures in the goitred gazelle Gazella subgutturosa

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    Abstract The potential for vocal modification in mammals has recently been of great interest. This study focuses on the potential for vocal matching in juvenile and adolescent goitred gazelles Gazella subgutturosa that were group housed as part of an animal management programme. Two groups of animals (16 and 19 unrelated individuals, respectively) were recorded at two different ages, juvenile and adolescent, regarding 20-25 calls per individual per age; each group was evaluated in a separate year. Vocal similarity of group members compared to nonmembers was prominent in both ages, but higher in juveniles. Individual identity was prominent in both ages and higher in adolescents. The more prominent vocal indicators of group membership in juveniles could be related to their higher social dependence compared to adolescents. The more individualized calls of adolescents could be a mechanistic consequence of more stable growth at older age. Our results suggest vocal plasticity of goitred gazelles under social influences. These data add to recent evidence about domestic goat kids Capra hircus, suggesting that vocalizations of species that are not capable of imitation are more flexible than previously thought

    Can Plasmon Change Reaction Path? : Decomposition of Unsymmetrical Iodonium Salts as an Organic Probe

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    Plasmon-assisted transformations of organic compounds represent a novel opportunity for conversion of light to chemical energy at room temperature. However, the mechanistic insights of interaction between plasmon energy and organic molecules is still under debate. Herein, we proposed a comprehensive study of the plasmon-assisted reaction mechanism using unsymmetric iodonium salts (ISs) as an organic probe. The experimental and theoretical analysis allow us to exclude the possible thermal effect or hot electron transfer. We found that plasmon interaction with unsymmetrical ISs led to the intramolecular excitation of electron followed by the regioselective cleavage of C–I bond with the formation of electron-rich radical species, which cannot be explained by the hot electron excitation or thermal effects. The high regioselectivity is explained by the direct excitation of electron to LUMO with the formation of a dissociative excited state according to quantum-chemical modeling, which provides novel opportunities for the fine control of reactivity using plasmon energy.Peer reviewe

    Reactions of 1-arylbenziodoxolones with azide anion: Experimental and computational study of substituent effects

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    New substituted 1-arylbenziodoxolones were prepared and their reactivity with azide anion nucleophile was investigated. It was found that independent on the presence of substituents, all reactions of 1-arylbenziodoxolones proceed as nucleophilic substitution of the iodonium leaving group in the electron-deficient benziodoxolone benzene ring. The presence of bulky substituents in the ortho-position of the aryl ring slowers the reaction, while the presence of a moderately electron-withdrawing bromine substituent in the para-position to iodine in the benziodoxolone ring moderately increases the rate of substitution. The presence of a strongly electron-withdrawing nitro group in the para-position to iodine in the benziodoxolone ring dramatically increases the rate of substitution. These observations are in agreement with the electronic requirements for internal nucleophilic substitution in the benziodoxole ring. A quantum-chemical computational study of the possible reaction paths is in agreement with the observed effects of substituents on the reactivity of arylbenziodoxolones in this reaction

    Zwitterionic iodonium species afford halogen bond-based porous organic frameworks

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    Porous architectures characterized by parallel channels arranged in honeycomb or rectangular patterns are identified in two polymorphic crystals of a zwitterionic 4-(aryliodonio)-benzenesulfonate. The channels are filled with disordered water molecules which can be reversibly removed on heating. Consistent with the remarkable strength and directionality of the halogen bonds (XBs) driving the crystal packing formation, the porous structure is stable and fully preserved on almost quantitative removal and readsorption of water. The porous systems described here are the first reported cases of one-component 3D organic frameworks whose assembly is driven by XB only (XOFs). These systems are a proof of concept for the ability of zwitterionic aryliodonium tectons in affording robust one-component 3D XOFs. The high directionality and strength of the XBs formed by these zwitterions and the geometrical constraints resulting from the tendency of their hypervalent iodine atoms to act as bidentate XB donors might be key factors in determining this ability

    Clinical complexity and impact of the ABC (Atrial fibrillation Better Care) pathway in patients with atrial fibrillation: a report from the ESC-EHRA EURObservational Research Programme in AF General Long-Term Registry

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    Background: Clinical complexity is increasingly prevalent among patients with atrial fibrillation (AF). The ‘Atrial fibrillation Better Care’ (ABC) pathway approach has been proposed to streamline a more holistic and integrated approach to AF care; however, there are limited data on its usefulness among clinically complex patients. We aim to determine the impact of ABC pathway in a contemporary cohort of clinically complex AF patients. Methods: From the ESC-EHRA EORP-AF General Long-Term Registry, we analysed clinically complex AF patients, defined as the presence of frailty, multimorbidity and/or polypharmacy. A K-medoids cluster analysis was performed to identify different groups of clinical complexity. The impact of an ABC-adherent approach on major outcomes was analysed through Cox-regression analyses and delay of event (DoE) analyses. Results: Among 9966 AF patients included, 8289 (83.1%) were clinically complex. Adherence to the ABC pathway in the clinically complex group reduced the risk of all-cause death (adjusted HR [aHR]: 0.72, 95%CI 0.58–0.91), major adverse cardiovascular events (MACEs; aHR: 0.68, 95%CI 0.52–0.87) and composite outcome (aHR: 0.70, 95%CI: 0.58–0.85). Adherence to the ABC pathway was associated with a significant reduction in the risk of death (aHR: 0.74, 95%CI 0.56–0.98) and composite outcome (aHR: 0.76, 95%CI 0.60–0.96) also in the high-complexity cluster; similar trends were observed for MACEs. In DoE analyses, an ABC-adherent approach resulted in significant gains in event-free survival for all the outcomes investigated in clinically complex patients. Based on absolute risk reduction at 1 year of follow-up, the number needed to treat for ABC pathway adherence was 24 for all-cause death, 31 for MACEs and 20 for the composite outcome. Conclusions: An ABC-adherent approach reduces the risk of major outcomes in clinically complex AF patients. Ensuring adherence to the ABC pathway is essential to improve clinical outcomes among clinically complex AF patients
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