131,445 research outputs found
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
Phylogenetic diversity of koala retrovirus within a wild koala population
No full textKoala populations are in serious decline across many areas of mainland Australia, with infectious disease a contributing factor. Koala retrovirus (KoRV) is a gammaretrovirus present in most wild koala populations and captive colonies. Five subtypes of KoRV (A to E) have been identified based on amino acid sequence divergence in a hypervariable region of the receptor binding domain of the envelope protein. However, analysis of viral genetic diversity has been conducted primarily on KoRV in captive koalas housed in zoos in Japan, the United States, and Germany. Wild koalas within Australia have not been comparably assessed. Here we report a detailed analysis of KoRV genetic diversity in samples collected from 18 wild koalas from southeast Queensland. By employing deep sequencing we identified 108 novel KoRV envelope sequences and determined their phylogenetic diversity. Genetic diversity in KoRV was abundant and fell into three major groups; two comprised the previously identified subtypes A and B, while the third contained the remaining hypervariable region subtypes (C, D, and E) as well as four hypervariable region subtypes that we newly define here (F, G, H, and I). In addition to the ubiquitous presence of KoRV-A, which may represent an exclusively endogenous variant, subtypes B, D, and F were found to be at high prevalence, while subtypes G, H, and I were present in a smaller number of animal
MeSH term explosion and author rank improve expert recommendations
No full textInformation overload is an often-cited phenomenon that reduces the productivity, efficiency and efficacy of scientists. One challenge for scientists is to find appropriate collaborators in their research. The literature describes various solutions to the problem of expertise location, but most current approaches do not appear to be very suitable for expert recommendations in biomedical research. In this study, we present the development and initial evaluation of a vector space model-based algorithm to calculate researcher similarity using four inputs: 1) MeSH terms of publications; 2) MeSH terms and author rank; 3) exploded MeSH terms; and 4) exploded MeSH terms and author rank. We developed and evaluated the algorithm using a data set of 17,525 authors and their 22,542 papers. On average, our algorithms correctly predicted 2.5 of the top 5/10 coauthors of individual scientists. Exploded MeSH and author rank outperformed all other algorithms in accuracy, followed closely by MeSH and author rank. Our results show that the accuracy of MeSH term-based matching can be enhanced with other metadata such as author rank
Going Beyond Counting First Authors in Author Co-citation Analysis
No full textThe 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
"Closing the R&D Gap, Evaluating the Sources of R&D Spending"
No full textBoth spending and tax policies have been implemented in the United States with the goal of stimulating private sector research and development (R&D). Karier questions whether current R&D policy, especially the research and experimentation tax credit, can contribute to closing the gap between nondefense expenditures on R&D in the United States and such expenditures in other countries, such as Japan and Germany. He also explores possible changes to our current R&D policy to make it more effective.
The equity premium in 100 textbooks
No full textI review 100 finance and valuation textbooks published between 1979 and 2008 by authors such as Brealey and Myers, Copeland, Damodaran, Merton, Ross, Bruner, Bodie, Penman, Weston, Brigham and Arzac and find that their recommendations regarding the equity premium range from 3% to 10%. I also find that several books use different equity premia on different pages. Some of the confusion arises from not distinguishing among the four concepts that the term equity premium designates: historical equity premium, expected equity premium, required equity premium and implied equity premium. Finance textbooks should clarify the equity premium by providing distinguishing definitions of these four concepts and conveying a clearer message about their sensible magnitudes.equity premium; equity premium puzzle; required market risk premium; historical market risk premium; expected market risk premium; risk premium; market risk premium; market premium;
Dispelling the Myths Behind First-author Citation Counts
No full textWe 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
Scholarly Communication and Publishing Lunch and Learn Talk #11: The ULS Open Access Author Fee Fund
No full textAt the May 2014 talk, you will learn about the ULS Open Access Author Fee Fund--what it is, why we do it, how it works, and how the program is going so far
The R&D Tax Incentives
No full textThis article sets out some background information and reflections of the author on the R&D tax incentive schemes included in the Common Corporate Tax Base (CCTB) Proposal. In particular the author analyzes the stimulus to private R&D through ad hoc tax incentives included in the CCTB Proposal and dives into the actual provisions included in the Proposal highlighting the most relevant issues connected with their design and interpretation. Moreover, the author explores the interaction between the CCTB Proposal and the granting by Member States of domestic R&D tax incentives
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