1,720,961 research outputs found
Effect of the uneven blade spacing on the noise annoyance of axial-flow fans and side channel blowers
No full textSeveral rotors of axial-flow fans and side channel blowers with optimal circumferential spacing have been tested in a hemi-anechoic chamber; such rotors have been designed by means of an existing method based on the minimization of the tonal noise peaks prominence from the broadband spectrum. The resulting SPL spectra contain different components: tonal ones, which are a well-known cause of annoyance (intended as an undesired feature of the received noise related to the short-term exposure), broadband ones, which could have a positive masking effect, and further components due to the electric motor. As expected, the blade spacing strongly affects the tonal noise part of the spectrum, which is mainly of aeroacoustic origin; in axial-flow fans, it also affects the low-frequency broadband part related to the leakage flow. The present study has also confirmed the good consistency between measured spectra and theoretically predicted ones even for side channel blowers. The characteristic curves of the tested machines are not significantly affected, but the quality of the radiated noise considerably changes as the spacing non-uniformity increases: tonalness decreases and roughness increases, fluctuation has not a systematic behavior, and no significant variation in other perceived characteristics may be noticed. In order to quantify such perception, the psychoacoustic parameters commonly employed for automotive cooling fans have been computed. The tonalness decrease leads to a significant annoyance reduction, while the increase in roughness seems of minor importance from a noise annoyance standpoint. Nevertheless, in strongly asymmetric rotors, the change in the perceived acoustic signature may be relevant and an unaware listener could interpret the roughness increase as a potential mechanical malfunction. As for generality of the present discussion, it should be considered that the tested rotors have been optimized in order to reduce the tonal noise peaks prominence, which obviously results in a reduction in the perceived tonalness. On the contrary, spacing obtained by means of different criteria could yield different variations in tonalness, and the same likely happens to loudness. Instead, the rise of peaks at shaft frequency harmonics is a direct consequence of the uneven spacing which should sistematically yield a roughness increase
Chemotherapeutic agents for the treatment of fungal infections. Imidazole derivatives highly active against Candida albicans
No full textFungi may be classified by the level of tissue affected as superficial, subcutaneous, and systemic. The term "opportunistic mycoses" is used to refer to serious fungal infections occurring in patients with compromised host defenses. The most common opportunistic mycoses include candidiasis, invasive aspergillosis, cryptococcal meningitis, and mucormycosis. During the past two decades, the incidence of these and other unusual opportunistic mycoses has been increasing, related to the use of broad-spectrum antibiotics, immusuppressive agents, anticancer and anti-AIDS drugs.
Recently, Lass-Flörl et al. reported the in vitro antifungal properties of selective serotonin reuptake inhibitors (SSRIs) against Aspergillus species and Candida parapsilosis. Fluoxetine (1) and sertraline (2) showed the highest activity against these fungi with differences in susceptibility of the various isolates tested. Starting from this report and pursuing our personal interest on azole antifungal agents, we synthesized novel antimicotic derivatives as econazole (3) isomers (4), replacing the fluoxetine NHCH3 terminus with an imidazole ring.1
All new derivatives, evaluated in vitro activity for their antifungal activity against 20 strains of Candida albicans, showed a very potent anti-Candida activity, higher than miconazole and econazole. 1-(4-Chlorophenyl)-1-(2,4-dichlorophenoxy)-3-(1H-imidazol-1-yl)-propane was about 2-fold more active than econazole. High increase of activity was observed with methyl, nitro, fluorine and chlorine (Cl>F>CH3>NO2>CF3).
References
(1) Silvestri, R.; Artico, M.; La Regina, G.; Di Pasquali, A.; De Martino, G.; D’Auria, F. D.; Nencioni, L.; Palamara, A. T. Imidazole Analogues of fluoxetine, a novel class of anti-Candida agents. J. Med. Chem. 2004, 47, in press
Derivati imidazolici isomeri dell’econazolo ad azione anti-Candida
No full textNegli ultimi anni è stato osservato un significativo aumento delle infezioni fungine; in particolar modo, è stato registrato un netto aumento delle infezioni topiche e sistemiche da Candida albicans, correlato all’uso eccessivo di antibiotici a largo spettro, di agenti immusopressori, antineoplastici ed anti-AIDS.
Recentemente Lass-Flörl et al. hanno riportato le proprietà antifungine di alcuni inibitori selettivi del reuptake della serotonina sulle specie Aspergillus e Candida parapsilosis.1 La fluoxetina (1) e la sertralina (2) hanno mostrato la più alta attività antimicotica. A partire da queste strutture sono stati progettati e sintetizzati nuovi derivati antifungini (4), isomeri dell’econazolo (3), per sostituzione del gruppo metilaminico della fluoexetina con il nucleo imidazolico.2
Tutti i composti sintetizzati sono stati testati su 20 ceppi di Candida Albicans in un range di concentrazione compreso fra 0,25 e 128 microg/ml.
I nuovi derivati imidazolici hanno mostrato una potente attività anti-Candida, superiore a miconazolo ed econazolo. Il 1-(4-clorofenil)-1-(2,4-diclorofenossi)-3-(1H-imidazol-1-il)-propano è risultato circa due volte più attivo (MIC=2,1±1,24 microM) dell’econazolo. Un elevato incremento di attività, infine, è stato osservato con l’introduzione dei gruppi (R1) metile, nitro, fluoro e cloro.
Bibliografia
(1) Lass-Flörl, C.; Dierich, M. P.; Fuchs, D.; Semenitz, E.; Jenewein, I.; Ledochowski, M. Antigungal properties of selective serotonin reuptake inhibitors against Aspergillus species. J. Antimicr. Chemoth. 2001, 48, 775-779. (2) Silvestri, R.; Artico, M.; La Regina, G.; Di Pasquali, A.; De Martino, G.; D’Auria, F. D.; Nencioni, L.; Palamara, A. T. J. Med. Chem. 2004, 47, in press
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
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
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