1,721,008 research outputs found
Qualitative Computed Tomographic Features Predict Epidermal Growth Factor Receptor Mutations in Advanced Lung Adenocarcinoma
Full text linkIntroduction: Current guidelines recommend reflex testing for EGFR mutations in patients with advanced lung adenocarcinoma. Although tissue biopsy is considered the “gold standard” for EGFR mutation testing, it may not always be feasible in a small group of patients.
Hence, this study aims to determine the computed tomography (CT) features that may predict the presence of common sensitising EGFR mutation in newly diagnosed advanced lung adenocarcinoma patients. Methods: 182 diagnostic contrast enhanced CT-images of newly
diagnosed advanced lung adenocarcinoma patients who attended University Malaya Medical Center from 2010 to 2014 were analysed. For EGFR mutation testing, tissue biopsy specimens of all patients were tested for exon 19 deletion and exon 21 L858R point mutation. Results:
Of the 182 patients, 158 patients with measurable primary tumour, were included in the analysis. 67 (42.4%) patients had common sensitising EGFR mutations, of which 43 (64.1%) were exon 19 deletion and 24 (35.9%) were exon 21 L858R point mutation. CT features of these patients are stated in Table 1. Common sensitising EGFR mutations were significantly more common in primary tumours with round contour (p ¼ 0.029), homogenous enhancement (p ¼ 0.029) and presence of air-bronchogram (p ¼ 0.029). On the other hand, presence of emphysema (p ¼ 0.005) and intrathoracic lymph nodes enlargement (p ¼ 0.001) were significantly against the presence of common sensitising EGFR mutations. These findings were further supported by the multivariate analysis: round contour [odd ratio (OR): 13.6, 95% confidence interval (CI): 1.40 - 13.2, p ¼ 0.024], homogenous enhancement (OR: 2.5, 95% CI: 1.00 - 6.47, p ¼ 0.049), presence of air bronchogram (OR: 2.7, 95% CI: 1.28 e 5.53, p ¼ 0.009) and intrathoracic lymph
nodes enlargement (OR: 0.2, 95% CI: 0.05 - 0.52, p ¼ 0.002). None of the CT features could differentiate exon 19 deletion from exon 21 L858R point mutation.
Conclusion: Tumours with round contour, homogenous enhancement and air bronchogram as well as absence of intrathoracic lymph nodes enlargement were independent predictors of the presence of common sensitising EGFR mutations. This information is helpful to clinicians in
selecting best empirical treatment for patients who are not eligible for tissue biopsy and in those who need urgent treatment because of rapid clinical deterioration
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
Common concerns in managing bronchial asthma during the COVID-19 pandemic
Full text linkThe use of corticosteroids and nebulised bronchodilators in bronchial asthma (BA) is a major concern during the COVID-19 pandemic. Inhaled corticosteroid (ICS) is the recommended treatment for all levels of BA severity, while oral corticosteroid (OCS) is used in severe asthma and acute exacerbation of BA (AEBA).1 Because corticosteroid is an immunosuppressant, BA patients on corticosteroid treatment are theoretically at a higher risk of contracting COVID-19 and may suffer more severe disease. Nebulisation of bronchodilators is a frequent treatment modality for patients attending an emergency department for AEBA because of a common perception that it is more effective and faster in symptom relief. However, nebulisation may cause dispersion of SARS-CoV-2 into the surrounding environment, putting other patients and
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healthcare workers at risk. There are several issues that need to be addressed. First, AEBA precipitated by COVID-19 is difficult to distinguish from other respiratory tract infections. Second, patients may have asymptomatic COVID-19 and their AEBA may be precipitated by other causes. Third, AEBA may be the only complaint of the COVID-19 patients, who lack symptoms such as fever, headache etc. In this Letter, we address some common concerns in managing BA during the COVID-19 pandemic.
First, are patients with BA more susceptible to SARS-CoV-2 infection? The prevalence of BA in COVID-19 patients in China is remarkably low (see Table). A recent study by Li et al. reported that only 0.9% of COVID-19 patients admitted to a hospital in Wuhan, China, had BA.2 Two other studies specifically looked for BA among COVID-19 patients but did not report any cases.3,4 BA was not included as a significant comorbidity reported by other studies conducted in China. In contrast, studies in the United States reported the prevalence of BA to be 17% among hospitalised COVID-19 patients and 9.1% among COVID-19 patients admitted to intensive care units, which is higher than the national average of 7.7%.5,6 Based on these data, there is no consistent evidence to suggest patients with BA are more susceptible to COVID-19.
The second concern is whether BA patients suffer from severe COVID-19 if infected by SARS-CoV-2. Li et al. reported that BA is not associated with more severe disease or higher mortality in COVID-19.2 To date, no other study has reported BA patients are at higher risk of poor outcomes or have more severe exacerbation if infected by SARS-CoV-2. Since SARS-CoV-2 utilises angiotensin-converting enzyme 2 (ACE-2) as a cellular entry receptor to infect the human host, one possible explanation for the reduced susceptibility of BA patients to SARS-CoV-2 infection and to severe COVID-19 is the reduced ACE-2 gene expression in nasal and bronchial epithelial cells in patients with allergic rhinitis and atopic asthma.7
Next, should regular ICS or OCS be withheld during the COVID-19 pandemic? The Global Initiative for Asthma and the National Institute for Health and Care Excellence has recommended continuation of ICS and OCS as clinically indicated during the COVID-19 pandemic.1 Withdrawal of corticosteroids may lead to worsening of asthma control and severe AEBA. Seeking treatment at healthcare facilities for uncontrolled BA during the pandemic may predispose these patients to SARS-CoV-2 infection and further overwhelm the healthcare facility. Therefore, corticosteroids should be maintained during the pandemic to keep BA under control. There is also some evidence suggesting ICS may be beneficial in treating COVID-19. First, the combination of ICS with bronchodilator has been shown to supress coronavirus replication and cytokine production in vitro.8 Second, inhaled ciclesonide, a corticosteroid
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commonly used to treat allergic rhinitis and BA has been shown to successfully treat three cases of COVID-19 pneumonia.9
A fourth concern is the administration of bronchodilators by nebulisers to patients with moderate-to-severe AEBA during the pandemic. Current evidence indicates that COVID-19 is transmitted by droplets, direct contact and fomites. Airborne transmission of COVID-19 from person-to-person has not been reported. However, nebulisation may promote airborne transmission of respiratory viruses, including SARS-CoV-2. Viable SARS-CoV-2 is reported in aerosols generated by jet nebuliser for up to 3 hours.10 The use of a jet nebuliser to deliver bronchodilators to a severe acute respiratory syndrome (SARS) patient was the cause of a major nosocomial SARS outbreak.11 SARS-CoV-2 has a higher binding affinity to the ACE-2 receptor than the SARS coronavirus. Therefore, it is very likely nebulisation of bronchodilators can cause aerosol transmission of COVID-19. If possible, nebulisation should be avoided. Airborne precautions should be strictly adhered to if nebulisation is unavoidable, such as in patients with life-threatening AEBA.
The fifth concern is how to administer bronchodilators for moderate-to-severe AEBA during the COVID-19 pandemic. Randomised control trials (RCTs) have reported that delivery of bronchodilators using pressurised meter-dose inhalers (pMDIs) with a spacer is equally effective and safe as nebulisation in adults with non-life-threatening AEBA.12 The 2005 joint report by the American College of Chest Physician and the American College of Asthma, Allergy and Immunology concluded that there is no significant difference in terms of efficacy and adverse outcomes among patients receiving pMDIs, dry powder inhalers (DPIs), or nebulisation for AEBA.13 Therefore, either pMDI with spacer or DPI can be used to administer bronchodilators in AEBA. The former does not depend on the patient’s inspiratory effort which is frequently reduced during AEBA, making it a better option than DPI. A meta-analysis of several RCTs concludes that patients with AEBA receiving a combination of inhaled short-acting ß2-agonist (SABA) and short-acting muscarinic antagonist (SAMA) are more likely to have lung function improvement and less likely to be hospitalised compared to inhaled SABA alone.14 Based on this evidence, pMDI of SABA and SAMA with a spacer is the most appropriate treatment for adults with moderate-to-severe AEBA.
Finally, the use of systemic corticosteroids to treat AEBA may raise safety concerns during the COVID-19 outbreak. Systemic corticosteroids significantly reduce hospitalisations and exacerbation relapse in adults with AEBA. To our knowledge, an adverse effect of systemic corticosteroids has only been reported in patients with severe SARS and Middle East Respiratory Syndrome (MERS), but not in patients with COVID-19. Guidelines by the WHO
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do not recommend against the use of systemic corticosteroids in COVID-19 patients if the use is clinically indicated, such as for AEBA.15 Therefore, short courses of systemic corticosteroids can be given to patients with AEBA during the COVID-19 pandemic.
In conclusion, other than avoiding nebuliser use, the management of BA during the COVID-19 pandemic is not different from the usual practice. However, more studies are needed to determine whether BA patients are more susceptible to COVID-19 or have more severe COVID-19
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
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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