1,720,968 research outputs found
Polarised light microscopy of human amniotic fluid: a rapid method to assess fetal lung maturity - a pilot study
No full textParticles of pulmonary surfactant can be detected in minute quantities of amniotic fluid; they appear as round birefringent particles of 0.5-3 µm diameter with a characteristic cross of polarisation. Two hundred and five samples of amniotic fluid of various gestational ages were examined microscopically under polarised light. The number of birefringent particles observed per µI of amniotic fluid correlated well with the percentage of phosphatidyl-choline in the sample. There was also good agreement with palmitate determinations, surface tension measurements, the lecithin:sphingomyelin ratio and the clinical data. This technique is simple and rapid and does not require counting surfactant particles
A recombinant fragment of human SP-D reduces allergic responses in mice sensitized to house dust mite allergens
No full textC57Bl6 mice sensitized to Dermatophagoides pteronyssinus and challenged with D. pteronyssinus allergen extract given intranasally followed by treatment with intranasal applications of a 60-kDa truncated, trimeric recombinant form of human SP-D (rfhSP-D) showed a significant reduction in serum IgE, IgG1, peripheral blood eosinophilia and airway hyperresponsiveness compared to saline or bovine serum albumin-treated controls.Intracellular cytokine staining of lung and spleen homogenates showed increases in interleukin (IL)-12 production in lung tissue and normalization of IL-12 and interferon (IFN)-gamma in spleen tissue. In previous studies we demonstrated the effectiveness of native SP-D and rfhSP-D in down-regulating allergic responses to allergens of Aspergillus fumigatus. The results reported here indicate that rfhSP-D can suppress the development of allergic symptoms in sensitized mice challenged with allergens of the common house dust mite
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe 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
Get PDF“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
Get PDFWe 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
Plasma and airway levels of surfactant protein D degradation reflect progression of ARDS in entilated patients with SARS-CoV-2
No full textBackground: Patients with COVID-19 present severe respiratory symptoms progressing to acute respiratory distress syndrome (ARDS). Upon infection, SARS-CoV-2 destroys cells expressing the ACE2 receptor including alveolar type II cells (AT2). These cells are found in the alveolar-capillary barrier which normally secrete pulmonary surfactant, a complex of lipid and surfactant proteins (SPA, SP-B, SP-C, SP-D). Exogenous surfactant therapy (mainly composed of phospholipids, SP-B, and SP-C) has been successful in treating neonatal respiratory distress syndrome (nRDS) caused by surfactant deficiency in preterm babies.Plasma SP-D has been proposed as a marker of lung injury in COVID-19 but so far, no reports have evaluated sequential SP-D levels in both airway and plasma. As part of a clinical trial repurposing surfactant therapy to treat adult ventilated COVID-19 patients, we hypothesized that plasma SP-D levels may reflect decreased lung integrity and that SP-D degradation in plasma and airway samples from COVID-19 patients may reflect disease progression and severity. Method(s): Enzyme-linked immunosorbent assay (ELISA) was used to quantify SP-D concentration in patient plasma and tracheal aspirate samples. Western Blotting was used to identify any protein degradation. Sequential daily plasma and airway samples were analysed. Result(s): SP-D concentration in serum was 10-20 times higher in patients ventilated for COVID-19 than in healthy volunteers. Additionally, the concentration of SP-D in plasma has shown to be 10-100-fold higher than in tracheal aspirates. Furthermore, degraded fragments of SP-D were detected at a higher ratio than intact SP-D in plasma of ventilated patients. This ratio decreased with administration of surfactant therapy (containing phospholipids and SP-B and SP-C but no SPA or SP-D). Conclusion(s): Increased serum SP-D and decreased tracheal aspirate SP-D from ventilated COVID-19 patients suggested leakage of pulmonary surfactant into the bloodstream caused by damage to the alveolar-capillary barrier in diseased lungs. The ratio of degraded vs. intact SP-D found in the plasma was compared before and after therapeutic surfactant administration. The results indicated that levels of SP-D in plasma and tracheal aspirates together with the ratio of degraded and intact SP-D in the plasma may be useful indicators of the severity of COVID-19 lung disease progression
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe 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
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