1,721,053 research outputs found
Circulating leukocytes and oxidative Stress in cardiovascular diseases: a state of the art
Full text linkIncreased oxidative stress from both mitochondrial and cytosolic sources contributes to the development and the progression of cardiovascular diseases (CVDs), and it is a target of therapeutic interventions. The numerous efforts made over the last decades in order to develop tools able to monitor the oxidative stress level in patients affected by CVDs rely on the need to gain information on the disease state. However, this goal has not been satisfactorily accomplished until now. Among others, the isolation of circulating leukocytes to measure their oxidant level offers a valid, noninvasive challenge that has been tested in few pathological contexts, including hypertension, atherosclerosis and its clinical manifestations, and heart failure. Since leukocytes circulate in the blood stream, it is expected that they might reflect quite closely both systemic and cardiovascular oxidative stress and provide useful information on the pathological condition. The results of the studies discussed in the present review article are promising. They highlight the importance of measuring oxidative stress level in circulating mononuclear cells in different CVDs with a consistent correlation between degree of oxidative stress and severity of CVD and of its complications. Importantly, they also point to a double role of leukocytes, both as a marker of disease condition and as a direct contributor to disease progression. Finally, they show that the oxidative stress level of leukocytes reflects the impact of therapeutic interventions. It is likely that the isolation of leukocytes and the measurement of oxidative stress, once adequately developed, may represent an eligible tool for both research and clinical purposes to monitor the role of oxidative stress on the promotion and progression of CVDs, as well as the impact of therapies
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
Right heart failure due to loss of right ventricular capture in a patient with atrioventricular junction ablation and biventricular pacing.
No full textWe describe the case of a patient with atrioventricular (AV) junction ablation and chronic biventricular pacing in which intermittent dysfunction of the right ventricular (RV) lead resulted in left ventricular (LV) stimulation alone and onset of severe right heart failure. Restoration of biventricular pacing by increasing device output and then performing lead revision resolved the issue. This case provides evidence that LV pacing alone in patients with AV junction ablation may lead to severe right heart failure, most likely as a result of iatrogenic mechanical dyssynchrony within the RV. Thus, probably this pacing mode should be avoided in pacemaker-dependent patients with heart failure
Amiodarone-induced pulmonary toxicity with an excellent response to treatment
Full text linkAmiodarone is an anti-arrhythmic drug widely used, but its administration can be associated with several adverse side-effects. Among these, amiodarone-induced pulmonary toxicity (APT) occurs in 4-17% of cases and, if not early diagnosed and treated, may evolve towards pulmonary fibrosis and respiratory failure. A 76 years-old-man went to the hospital for accidental trauma. The patient did not report respiratory symptoms but was suffering from atrial fibrillation treated with amiodarone 200 mg/day from three years (cumulative dose >150 gr). HRCT showed ground-glass opacities and nodules in both lungs. The patient underwent fibreoptic bronchoscopy with BAL. Cytologic examination of BALF sediment put in evidence foamy macrophages. The electronic microscopy revealed into the alveolar macrophages "... the presence of multilamellar intracytoplasmic bodies and lysosomes, loads of lipid material". LFTs showed a restrictive syndrome and an impairment of DLCO. Amiodarone discontinuation and steroid administration led to the regression of radiological lesions and the recovery of lung function. Patients taking amiodarone can experience APT. They should perform a basal chest x-ray with LFTs before starting therapy. Monitoring could reveal early the pulmonary toxicity, and patients can respond favourably to the treatment
On orbit inspection with CubeSats: State of the art and future perspective
No full textThe current Space Agencies exploration programme encompasses the analysis and development of gap-filling activities towards future reliable missions. Within this context, examples of these activities could be found in orbit debris management, reusable Space Transportation Systems and orbital stations based on the heritage of the ISS. For all of these, a system performing on orbit inspection could represent an opportunity to increase both mission reliability and safety, while reducing the need of Astronauts Extra Vehicular Activity. Indeed, a constant monitoring of the external conditions of a target could: 1) track down damages and geometry of components 2) support maintenance activities 3) identify and characterize dynamics and materials. Since the introduction of the CubeSat standard in the early 2000s, there has been a proliferation of nanosatellites in Low Earth Orbit with more than 100-200 launched annually, pushing towards interplanetary applications. It has been verified that CubeSats can efficiently support a wide range of space missions: several studies have been already conducted and are ongoing. For example, the CubISSat mission to inspect the International Space Station has been developed within SysNova ESA framework with interesting results. Other examples are the e-Inspector CDF study, a mission targeted at gathering data about Envisat to prepare the removal mission and the ESA SROC study, a mission targeted at the observation of the new-born Space Rider. The paper presents design solutions for CubeSats equipped with stereoscopic vision system and hyperspectral camera payloads, involved in the visual inspection of specific target. Different mission concepts and CubeSat configurations are evaluated and compared. For each solution, advantages and challenges that impact both on payload performances and system requirements are identified and discussed. A preliminary study is presented on the quality of the multispectral information in relation to the changes in distance from the target, spectral bands involved, relative velocity and spectral resolution. Similarly, stereoscopic system performances are analysed with respect to spatial resolution of the camera, field of view, image size and complexity of the algorithms for data processing. All these parameters impose constraints on the CubeSat design and assembly in terms of features such as pointing accuracy and stability, precise attitude control and navigation, data storage capability, processor throughput and data rate. Thanks to the analysis of general case studies, a baseline feasibility analysis of an inspection mission is then traced, taking into account the most promising COTS CubeSat-based technology but facing the state of the art towards more effective future missions. As a result, a technology development roadmap is suggested, highlighting critical accomplishments to fulfil in order to improve reliability and performances of inspection missions. Giving an overview of current and future capabilities of CubeSats for inspection missions, this paper aims to put the basics for future CubeSat applications development, assisting the human vision of space exploration
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
- …
