1,720,959 research outputs found
An Enhanced Sherwood Number to Model the Hydrogen Transport in Membrane Steam Reformers
Full text linkIt is well known that membrane reactors are inherently two-dimensional systems in which species concentrations vary as a consequence of both the reaction and permeation across the membrane, which occurs in the direction perpendicular to that of the main gas flow. Recently, an expression for an enhanced Sherwood number was developed to describe the hydrogen concentration gradients arising in methane steam-reforming membrane reactors as a consequence of the combined effect of hydrogen production, dispersion, and permeation. Here, the analysis is developed in further detail with the aim of (i) assessing the validity of the simplifying assumptions made when developing the 1D model and (ii) identifying the operating conditions under which it is possible to employ the 1D model with the enhanced Sherwood number
Standardized bilateral thoracic ultrasound image comparison as a tool for the diagnosis of pneumothorax: a pilot exploratory study
No full textAim: Pneumothorax is a potentially life-threatening condition whose diagnosis can be challenging. Ultrasound chest examination is generally fast and user-friendly, but in non-expert hands or with uncooperative patients, it may still be difficult and time-consuming. Adding another tool to support the suspicion of pneumothorax might be useful, potentially enhancing the diagnostic accuracy of standard ultrasound chest examination. We evaluated the feasibility of standardized bilateral ultrasound image comparison as a potential new tool for pneumothorax diagnosis. Materials and methods: We enrolled 60 subjects (30 with pneumothorax and 30 controls) and collected bilateral ultrasound images of their chests (each image contained one frame from the left lung and one from the right lung). Ten physicians (eight blinded to diagnosis) divided into five groups according to expertise evaluated the images for potential grayscale differences and/or horizontal artifacts between the two frames. All images were then analyzed with image analysis software for grayscale pixel assessment (one sub-analysis for the entire area under the pleural line, one for a 100-pixel-wide rectangle under the pleural line). Results: All clinicians achieved good results in terms of diagnostic accuracy and inter-operator reliability, even those unexperienced in ultrasound. Mean, range, and median grayscale pixel ratio between the pneumothorax side and the healthy side in a single patient proved to be the most reliable parameters, reaching excellent sensitivity and specificity. Combining these parameters proved to be an excellent diagnostic tool (ROC area under curve = 1.00, p-value = 0.02). Conclusions: Standardized bilateral thoracic ultrasound image comparison may be a potential new tool for the diagnosis of pneumothorax
SMALL AIRWAYS DISEASE AND Z-ALPHA1-ANTITRYPSIN POLYMERS: IS THERE A CORRELATION?
No full textPURPOSE: The aim of the study was to assess the presence of small airways dysfunction and the potential correlation with the presence of Z-AAT polymers obtained by Exhaled Breath Condensate (EBC) collection in PiZZ subjects, comparing with matched healthy PiMM subjects.
METHODS: We enrolled 17 asymptomatic non-smoker subjects: 9 PiZZ and 8 PiMM as controls, without obstructive ventilatory defect (i.e.: normal FEV1/VC ratio). All subjects underwent complete pulmonary function tests (PFT). EBC was collected in PiZZ patients. ELISA test was applied to search for Z-AAT polymers.
RESULTS: The PiZZ subjects showed normal lung volumes and DLCO values. However, In comparison with PiMM subjects, the single breath test N2 wash-out revealed significant differences regarding the phase III slope (1.50.4 N2/L vs 1.10.3 N2/L) and the closing volume/vital capacity ratio (14.34.5 % vs 9.55.3 %) (p<0.05) in the PiZZ subjects. The ELISA test detected the presence of Z-AAT polymers in 4 PiZZ patients. No correlations were found between polymers levels and any functional respiratory parameter.
CONCLUSIONS: PiZZ subjects showed small airways dysfunction when compared to PiMM subjects. Surprisingly, Z-AAT polymers were found only in 4 PiZZ subjects; this is probably due to the sample methodology. New studies are needed to evaluate the correlation between bronchial Z-AAT polymers and small airway impairment in subjects with Z-AAT deficiency.
CLINICAL IMPLICATIONS: The presence of Alpha1-Antitrypsin (AAT) polymers that are pro-inflammatory has been previously demonstrated in bronchial biopsies of subjects with Z-AAT deficiency (Respir Res, 2014 Sep 14;15:112), suggesting a possible role in the development of COPD
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
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