1,720,966 research outputs found
Emerging antibiotic resistance: carbapenemase-producing enterobacteria. New bad bugs, still no new drugs
No full textAntimicrobial resistance (AMR) is recognized to be a global threat to health security, requiring action across government sectors and society. Many factors are involved in this phenomenon, overuse of antibiotics, incorrect antibiotic prophylaxis, and use of antibiotics for livestock purposes being the main causes of the increasing rate of multi-drug resistant (MDR) bacteria. The impact of resistance to antimicrobials is a major threat due also to the emergence of MDR Gram-negative bacteria resistant to carbapenems, and the lack of research to find new active molecules. The production of extended spectrum beta-lactamase enzymes was the first threatening mechanism for Gram-negative resistance to antibiotics, which prompted the development of new classes of antibiotics such as carbapenems. Unfortunately, resistance to carbapenems developed because of multiple mechanisms including efflux pumps, porin mutations and enzyme production, the latter being particularly relevant in terms of diffusion due to the genes located within plasmids that drive their horizontal diffusion. In this scenario, antimicrobial stewardship programs (ASP) are a mandatory resource in combating the spread of resistance. Reducing the total amount of antibiotics administration in the hospital setting and guiding prescribers in the correct administration of antibiotics for the shortest period possible, at the correct dosage, can be defined as the first goals of an ASP. That said, in an efficacious ASP, apart from antibiotic administration, efforts must be made to ensure the lowest probability of spreading MDR by efficacious measures of carrier isolation, and by offering tools for a rapid diagnosis of viral infections, thereby avoiding the administration of unnecessary antibiotics. A continuous audit of the ASP programs and correct assessment of the allergy to drugs such as penicillin should complete the program. Currently, few options are available for patients with an infection sustained by Gram-negative MDR bacteria. All the options currently available are based on the administration of colistin, an old drug whose real efficacy is reduced due to its high toxicity, or on the administration of recently proposed drugs such as ceftolozane-tazobactam, ceftazidime-avibactam and meropenem-vaborbactam. None of these new drugs have a novel mechanism of action and they have a limited spectrum in terms of activity against MDR bacteria. In conclusion, antimicrobial resistance is a global emergency and AMP is the most powerful tool currently available. Few options are available to treat infections due to Carbapenem-resistant Enterobacteria. Antimicrobial molecules with true novel mechanisms of action are needed to win the fight against antimicrobial resistance
Infections causing stroke or stroke-like syndromes
No full textBackground: Stroke has relevant morbidity and mortality despite appropriate treatments and early diagnosis. Beside common risk factors such as diabetes and atrial fibrillation, infections can be involved in stroke pathogenesis, probably causing a systemic release of cytokines and other inflammatory mediators, triggering a latent pro-thrombotic state or damaging the vascular endothelium. In other cases, infections can occur as stroke-like syndromes, requiring a high grade of suspicion to avoid a delay in establishing a correct diagnosis. Results: Treatment of stroke or stroke-like syndromes of infectious origin can be difficult. When a previous infective event triggers stroke, Alteplase administration can be associated with a higher incidence of bleeding and the extension of the ischaemic area can be major than expected. On the other hand, when stroke is part of some infectious diseases’ presentation as in endocarditis, bacterial or tuberculous meningitis and meningo-vascular syphilis, a correct diagnosis can be difficult. The management of these stroke-like syndromes is not standardised because common treatments proven to be effective for patients with stroke of vascular origin can worsen the prognosis, as it can be demonstrated after to be incorrect Alteplase administration to patients with endocarditis with septic embolism to the brain is associated with an increase of the risk of haemorrhage. Conclusions: Stroke or stroke-like syndrome of infectious origin can be observed in an important proportion of case presenting with sensory-motor deficit of unknown origin; their accurate diagnosis has a considerable impact in terms of treatment choices and outcome
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
CO2 Laser Welding of Aluminium Shipbuilding Industry Alloys: AA 5083, AA 5383, AA 5059, and AA 6082
No full textAluminium alloys are interesting in many and many industrial applications, from the classical aircraft industry to rail and road vehicles manufacturing (High Speed Train, Car Structure and Body). Recently much more attention for Aluminium Alloys, 5000 and 6000 Series, has been carried out by Shipbuilding Industry, especially for using in the H.S.L.C. (High Speed Light Craft). Therefore the aim of this experimental work has been to study, develop and test a reproducible CO2 laser welding procedure and technique on four specific alloys, that is AA 5083, AA 5383, AA 5059 (Al-Mg Alloys), and AA 6082 (Al-Mg-Si Alloy). Different techniques, methodologies, covering gases, nozzles, focusing lenses and mirrors, welding speed range, laser power range (1000 and 2500 W) have been carefully experimented. The melted zones properties have been evaluated by cross sections, and some visual inspections by a NIKON LUCIA Imaging System correlating each experimental test, results and evaluations to the adopted process parameters and to the thermo-physical properties of the tested alloys
CO2 Laser Welding of Aluminium Shipbuilding Industry Alloys: AA 5083, AA 5059, AA 5383 and AA 6082
No full textAluminium alloys are interesting in many and many industrial applications, from the classical aircraft industry to rail and road vehicles manufacturing (High Speed Train, Car Structure and Body). Recently much more attention for Aluminium Alloys, 5000 and 6000 Series, has been carried out by Shipbuilding Industry, especially for using in the H.S.L.C. (High Speed Light Craft). Therefore the aim of this experimental work has been to study, develop and test a reproducible CO2 laser welding procedure and technique on four specific alloys, that is AA 5083, AA 5383, AA 5059 (Al-Mg Alloys), and AA 6082 (Al-Mg-Si Alloy). Different techniques, methodologies, covering gases, nozzles, focusing lenses and mirrors, welding speed range, laser power range (1000 and 2500 W) have been carefully experimented. The melted zones properties have been evaluated by cross sections, and some visual inspections by a NIKON LUCIA Imaging System correlating each experimental test, results and evaluations to the adopted process parameters and to the thermo-physical properties of the tested alloys
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
- …
