1,721,004 research outputs found
High resolution small animal single photon emission computed tomography: uptake of [(99m)Tc]bombesin and [(123)I]ioflupane by rat brain.
No full textThe aims of this study were: 1) to perform brain single photon emission computed tomography (SPECT) in anesthetized rats with high resolution cameras (HRC) equipped with parallel hole collimation resolution of about 1 mm (HRC1) and 2 mm (HRC2); 2) to assess when and with which radio-tracer HRC1 SPECT shows advantages over HRC2.We used two multicrystal HRCs with parallel square hole collimators, whose pure tungsten septa closely fit the crystals, in turn matched with a 4 inch2 position sensitive photomultiplier. HRC1 showed 1.1 mm and HCR2 2.1 mm resolution at collimator contact. HRCs performed 180 degrees semi-circular orbits around the head of rats: image reconstruction occurred with ordered subsets expectation maximization algorithms. Resolution of SPECT was measured with a Derenzo Phantom, resulting 1.4 mm for HRC1 and 2.3 mm for HRC2. Three rats were studied with [(99m)Tc]HMPAO, 3 rats with [(99m)Tc]bombesin (BN) and 48 h later with [(123)I]ioflupane (DaTSCAN). SPECT studies were reviewed by two experienced operators.Technetium-99m-HMPAO SPECT showed similar images with HRC1 and HRC2. The uptake of BN by amygdale, hippocampus and olfactory tract was detected by both cameras. DaTSCAN SPECT with HRC1 showed detailed image of the tail of the caudatus: this image was not obtained with HRC2. DaTSCAN and BN SPECT showed amygdale with both HRCs. However, only the central nucleus of amygdale takes up DaTSCAN, whereas central, lateral and basolateral amygdaloid nuclei express BN receptors. Only HRC1 SPECT showed amygdale larger with BN than with DaTSCAN.Spatial resolution of 1.4 mm is appropriate to detect selected subcerebral structures
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
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
Appropriate 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
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
Room Temperature Al18F Labeling of 2-Aminomethylpiperidine-Based Chelators for PET Imaging
No full textPositron emission tomography (PET) is a non‐invasive molecular imaging technology that is constantly expanding, with a high demand for specific antibody‐derived imaging probes. The use of tracers based on temperature‐sensitive molecules (i. e. Fab, svFab, nanobodies) is increasing and has led us to design a class of chelators based on the structure of 2‐aminomethylpiperidine (AMP) with acetic and/or hydroxybenzyl pendant arms (2‐AMPTA, NHB‐2‐AMPDA, and 2‐AMPDA‐HB), which were investigated as such for {Al18F}2+‐core chelation efficiency. All the compounds were characterized by HPLC‐MS analysis and NMR spectroscopy. The AlF‐18 labeling reactions were performed under various conditions (pH/temperature), and the radiolabeled chelates were purified and characterized by radio‐TLC and radio‐HPLC. The stability of labeled chelates was investigated up to 240 min in human serum (HS), EDTA 5 mM, PBS and 0.9 % NaCl solutions. The in vivo stability of [Al18F(2‐AMPDA‐HB)]− was assessed in healthy nude mice (n=6). Radiochemical yields between 55 % and 81 % were obtained at pH 5 and room temperature. High stability in HS was measured for [Al18F(2‐AMPDA‐HB)]−, with 90 % of F‐18 complexed after 120 min. High stability in vivo, rapid hepatobiliary and renal excretion, with low accumulation of free F‐18 in bones were measured. Thus, this new Al18F‐chelator may have a great impact on immuno‐PET radiopharmacy, by facilitating the development of new fluorine‐18‐labeled heat‐sensitive biomolecules
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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