667 research outputs found

    Development of a fast screening method for the direct determination of chlorinated persistent organic pollutants in fish oil by high-resolution continuum source graphite furnace molecular absorption spectrometry

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    The authors are grateful to the Conselho Nacional de Desenvolvimento Científico and Tecnológico (CNPq); the present research was mostly financed through Project no. CNPq 406877/2013-0. The authors are also grateful to the Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) for financial support and scholarships, and to Analytik Jena for financial support and donation of the contrAA 600 high-resolution continuum source atomic absorption spectrometer.Peer reviewedPostprin

    Investigation of chemical modifiers for the determination of cadmium and chromium in fish oil and lipoid matrices using HR-CS GF AAS and a simple ‘dilute-and-shoot’ approach

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    The authors are grateful to the Conselho Nacional de Desenvolvimento Científico and Tecnológico (CNPq), and Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) for financial support and scholarships. The present research was mostly financed through Project no. CNPq 406877/2013-0. The authors are also grateful to Analytik Jena for financial support and the donation of the contrAA 600.Peer reviewedPostprin

    Two-photon interference with true thermal light

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    Two-photon interference and "ghost" imaging with entangled light have attracted much attention since the last century because of the novel features such as non-locality and sub-wavelength effect. Recently, it has been found that pseudo-thermal light can mimic certain effects of entangled light. We report here the first observation of two-photon interference with true thermal light.Comment: 4 pages, 5 figures, PRA72, 043805 (2005

    Determination of arsenic in agricultural soil samples using High-resolution continuum source graphite furnace atomic absorption spectrometry and direct solid sample analysis

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    The authors are grateful to the Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq), and Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) for financial support and scholarships. BW had a research scholarship from CNPq, Processo No. 303526/2016-5. The authors are also grateful to Analytik Jena for the donation of the HR-CS GF AAS Model contrAA 600 and for financial support.Peer reviewedPostprin

    Investigation of the feasibility to use Zeeman-effect background correction for the graphite furnace determination of phosphorus using high-resolution continuum source atomic absorption spectrometry as a diagnostic tool

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    The determination of phosphorus by graphite furnace atomic absorption spectrometry at the non-resonance line at 213.6 nm, and the capability of Zeeman-effect background correction (Z-BC) to deal with the fine-structured background absorption due to the PO molecule have been investigated in the presence of selected chemical modifiers. Two line source atomic absorption spectrometers, one with a longitudinally heated and the other with a transversely heated graphite tube atomizer have been used in this study, as well as two prototype high-resolution continuum source atomic absorption spectrometers, one of which had a longitudinally arranged magnet at the furnace. It has been found that Z-BC is capable correcting very well the background caused by the PO molecule, and also that of the NO molecule, which has been encountered when the Pd + Ca mixed modifier was used. Both spectra exhibited some Zeeman splitting, which, however, did not cause any artifacts or correction errors. The practical significance of this study is to confirm that accurate results can be obtained for the determination of phosphorus using Z-BC. The best sensitivity with a characteristic mass of m(0) = 11 ng P has been obtained with the pure Pd modifier, which also caused the lowest background level. The characteristic mass obtained with the mixed Pd + Ca modifier depended on the equipment used and was between m(0) = 9 ng P and m(0) = 15 ng P, and the background signal was higher. The major problem of Z-BC remains the relatively restricted linear working range

    Evidence for a second class of S-adenosylmethionine riboswitches and other regulatory RNA motifs in alpha-proteobacteria

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    BACKGROUND: Riboswitches are RNA elements in the 5' untranslated leaders of bacterial mRNAs that directly sense the levels of specific metabolites with a structurally conserved aptamer domain to regulate expression of downstream genes. Riboswitches are most common in the genomes of low GC Gram-positive bacteria (for example, Bacillus subtilis contains examples of all known riboswitches), and some riboswitch classes seem to be restricted to this group. RESULTS: We used comparative sequence analysis and structural probing to identify five RNA elements (serC, speF, suhB, ybhL, and metA) that reside in the intergenic regions of Agrobacterium tumefaciens and many other α-proteobacteria. One of these, the metA motif, is found upstream of methionine biosynthesis genes and binds S-adenosylmethionine (SAM). This natural aptamer most likely functions as a SAM riboswitch (SAM-II) with a consensus sequence and structure that is distinct from the class of SAM riboswitches (SAM-I) predominantly found in Gram-positive bacteria. The minimal functional SAM-II aptamer consists of fewer than 70 nucleotides, which form a single stem and a pseudoknot. Despite its simple architecture and lower affinity for SAM, the SAM-II aptamer strongly discriminates against related compounds. CONCLUSION: SAM-II is the only metabolite-binding riboswitch class identified so far that is not found in Gram-positive bacteria, and its existence demonstrates that biological systems can use multiple RNA structures to sense a single chemical compound. The two SAM riboswitches might be 'RNA World' relics that were selectively retained in certain bacterial lineages or new motifs that have emerged since the divergence of the major bacterial groups

    Improved Heat Exchanger Lifecycle Prognostic Methods for Enhanced Light Water Reactor Sustainability

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    As the licenses of many nuclear power plants in the US and abroad are being extended, accurate knowledge of system and component condition is becoming increasingly important. The US Department of Energy (DOE) has funded a project with the primary goal of developing lifecycle prognostic methods to generate accurate and continuous Remaining Useful Life (RUL) estimates as components transition through unique stages of the component lifecycle. Specific emphasis has been placed on creating and transitioning between three distinct stages of operational availability. These stages correspond to Beginning Of Life (BOL) where little or no operational information is available, early onset operations at various expected and observed stress levels where there is the onset of detectable degradation, and degradation towards the eventual End Of Life (EOL). This paper provides an application overview of a developed lifecycle prognostic approach and applies it to a heat exchanger fouling test bed under accelerated degradation conditions resulting in an increased understanding of system degradation. Bayesian and Bootstrap Aggregation methods are applied to show improvements in RUL predictions over traditional methods that do not utilize these methods, thereby improving the lifecycle prognostic model for the component. The analyses of results from applying these lifecycle prognostic algorithms to a heat exchanger fouling experiment are detailed

    Selection of diazotrophic bacterial communities in biological sand filter mesocosms used for the treatment of phenolic-laden wastewater

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    Agri effluents such as winery or olive mill waste-waters are characterized by high phenolic concentrations. These compounds are highly toxic and generally refractory to biodegradation. Biological sand filters (BSFs) represent inexpensive, environmentally friendly, and sustainable wastewater treatment systems which rely vastly on microbial catabolic processes. Using denaturing gradient gel electrophoresis and terminal-restriction fragment length polymorphism, this study aimed to assess the impact of increasing concentrations of synthetic phenolic-rich wastewater, ranging from 96 mg L−1 gallic acid and138 mg L−1 vanillin (i.e., a total chemical oxygen demand (COD) of 234 mg L−1) to 2,400mg L−1 gallic acid and 3,442 mg L−1 vanillin (5,842 mg COD L−1), on bacterialcommunities and the specific functional diazotrophic community from BSF mesocosms. This amendment procedure instigated efficient BSF phenolic removal, significant modifications of the bacterial communities, and notably led to the selection of a phenolic-resistant and less diverse diazotrophic community. This suggests that bioavailable N is crucial in the functioning of biological treatment processes involving microbial communities, and thus that functional alterations in the bacterial communities in BSFs ensure provision of sufficient bioavailable nitrogen for the degradation of wastewater with a high C/N ratio.Web of Scienc

    Die Rangfolge psychischer und sozialer PrĂ€diktoren und Kriterien fĂŒr die Prognose Herztransplantierter

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    Bei 44 Herztransplantierten wurden prĂ€operativ und bis zu einem und drei Jahre postoperativ psychiatrisch/psychologische Untersuchungen durchgefĂŒhrt und psychosoziale Daten erhoben. Die PrĂ€diktoren und Kriterien fĂŒr eine gute Prognose wurden ihrer Rangfolge nach hierarchisiert. Es ergab sich folgende PrĂ€diktorrangfolge: 1. die eindeutige Motivation und der unauffĂ€llige psychopathologische Befund, 2. der gute soziale RĂŒckhalt und die vor der Transplantation zum Ausdruck gebrachte positive Berufsperspektive, 3. das Bewußtsein der Geborgenheit durch die Familie und die reife psychologische Verarbeitung der Herzerkrankung und der bevorstehenden Herztransplantation, 4. der fortgeschrittene Schweregrad der Herzerkrankung (Schweregrad IV NYHA), 5. der relativ geringe Fernsehkonsum (weniger als an 4 Abenden), und 6. u. a. noch lebende Eltern und das Vorhandensein von Kindern. FĂŒr die 7 prognostischen Kriterien ließ sich folgendeKriterienrangfolge ermitteln: 1. die soziale Reintegration, 2. die Lebenszufriedenheit, 3. die Compliance und der psychopathologische Befund, 4. die berufliche Rehabilitation, und 5. die körperliche Belastbarkeit und der körperliche Zustand. Die Studie zeigt, daß es eine unterschiedliche Gewichtung psychosozialer Faktoren vor und nach der Herztransplantation gibt, und daß die soziale Reintegration der beste Indikator fĂŒr eine erfolgreiche Herztransplantation ist.44 patients underwent psychiatric/psychological and psychosocial examinations before and for one to three years after heart transplantation. Predictors and prognostic criteria for a good result were established according to the rank of their significance. The rank sequence for the predictors were 1. strong motivation and absence of psychiatric symptomatology, 2. good social support and determination to return to work after transplantation, 3. the feeling of being cared for by the family and a mature psychological coping with the heart disease and the expected transplantation, 4. advanced heart failure (stage IV NYHA), 5. watching TV less than 4 evenings a week, 6. parents still living and having one’s own children. The rank sequence for the 7 prognostic criteria for a good result after heart transplantation were 1. social reintegration, 2. being content with life. 3. good compliance and absence of psychopathology, 4. returning to work, and 5. physical exercise tolerance and general physical condition. The study shows that there is a different magnitude of significance for psychosocial factors before and after heart transplantation and that social reintegration is the best indicator for a good result after heart transplantation
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