1,720,968 research outputs found
Cyclotron production of very high specific activity radionuclides for toxicological uses, at LASA-INFN: radiochemical separation and quality control
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Measurement of Actinides in Biological System; Radioanalytical determination of americium in human urines by extraction chromatography and high resolution alpha-spectrometry
No full textWithin the radiation protection physical surveillance program of some workers, involved in the decommissioning operations of a nuclear reprocessing plant of the Italian National Agency for New Technologies Energy and Environment, CR Saluggia (ENEA) in the North of Italy, some radiotoxicological analyses, on human urines, have been carried out, in order to determine the possible internal contamination of 241Am. After an in-depth study of a former extraction Chromatographic method, based on the use of Microthene-722 supporting HDEHP, a more suitable method has been developed and adopted in our laboratory, based on the use of TRU-Resin. This paper reports the results obtained with these two procedures as well as a comparison between them
Cyclotron production, radiochemical separation and quality control of platinum radiotracers for toxicological studies
No full textThe increasing concn. of Pt, Pd, and Rh in the environment is mainly due to the release of these elements from the catalytic converters of the motor vehicles. This situation makes it necessary to carry out metallotoxicol. expts. on both cell cultures and lab. animals, in order to assess their impact on living organisms after a long-term and low-level exposure (LLE). Both nuclear reactions natIr(p,xn) and natOs(α,xn) were investigated in the energy range up to 45 MeV for protons and 38 MeV for alpha-particles, to optimize the irradn. parameters for the prodn. of 188,189,191Pt. Several sets of thin- and thick-target excitation functions were detd. exptl. by cyclotron irradn. at both Milano and Ispra cyclotrons. This paper reports the irradn. parameters studied and adopted and two radiochem. procedures for the sepn. of radio-Pt from an Os target, as well as from ruthenium, iridium and gold impurities. These procedures were used to obtain very high specific activity Pt radionuclides in No Carrier Added (NCA) form. Radionuclidic, radiochem. and chem. purity measurements were carried out by the use of several techniques like γ-spectrometry, ion-exchange radio-chromatog., at. absorption spectrometry, and neutron activation anal
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Cyclotron production of Pt, Pd and Rh radiotracers to study the environmental impact of the catalytic converter emissions
No full textPt, Pd and Rh radioisotopes were produced by irradn. using both α and proton beams of the SCANDITRONIX MC40 cyclotron of JRC-Ispra with iridium, osmium, palladium and rhodium targets. Preliminary exptl. yields of 189Pt, 188Pt, 191Pt, 103Pd, 100Rh and 101mRh isotopes, employed for biol. applications, are presented
Cyclotron production, Radiochemical separation and quality control of very high specific activity radiotracers for toxicological studies
No full textThe use of High Specific Activity Radiotracers, obtained by either proton or alpha cyclotron irradiation, followed by selective radiochemical separation from the irradiated target in No Carrier Added form, is a powerful analytical tool. The main applications of this method are related to toxicological, environmental and industrial studies, other than to nuclear medicine radiodiagnostic. Some relevant original data on the optimised cyclotron production of technetium and platinum γ-emitting radionuclides are presented
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Determination of calibration curves for I-131 in thyroid tumour metabolic radiotherapy and other radionuclides used in SPECT imaging
No full textAppropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
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