1,721,003 research outputs found
Mixed complexes of N,N'-ethylenebis(salicylideneiminato)uranium(IV)
No full textSome mixed N,N′-ethylenebis(salicylideneiminato), salen, complexes of uranium(IV) of formula U(salen)X2(X = Cl, acetylacetonato, dipivaloylmethanato, N-methylsalicylideneiminato, dibenzoylmethanato) are reported. It is shown that U(salen)2 and UCl4 undergo a ligand redistribution reaction in tetrahydrofuran (THF) leading to U(salen)Cl2,2THF. Chemical and mass spectrometric data are presented supporting the monomeric structure of the complexes of formula U(salen)(chelate)2. Evidence is presented suggesting the transitory formation of the adduct U(salen)2,UCl4 in the course of the redistribution reaction leading to U(salen)Cl2
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
Alterazioni citogenetiche (micronuclei) in infermieri professionalmente esposti a farmaci antineoplastici: revisione sistematica e meta-analisi della letteratura
No full textINTRODUZIONE
I farmaci antiblastici (AB) sono un gruppo di sostanze chimiche note per il loro effetto mutageno/cancerogeno.
Il possibile rischio genotossico da esposizione professionale ha sollevato crescenti preoccupazioni nel personale sanitario coinvolto nella loro manipolazione, nonostante il significativo miglioramento delle politiche di sicurezza. Infatti, molti studi hanno dimostrato, mediante il monitoraggio biologico [micronuclei (MN) o aberrazioni cromosomiche (AC) su linfociti di sangue periferico] un rischio genotossico da esposizione lavorativa.
CONTENUTI
È stata condotta una revisione meta-analitica degli studi di epidemiologia molecolare, al fine di valutare l’associazione tra esposizione occupazionale ad AB e frequenza di effetti genotossici espressi come MN, nel comparto occupazionale considerato. La ricerca è stata effettuata tramite Pubmed, selezionando lavori sull’uomo in inglese, in extenso, cross-sectional con valutazione degli effetti biologici dell’esposizione ad AB in personale sanitario coinvolto in attività di preparazione, somministrazione e smaltimento, e che riportassero dati medi di gruppo relativi alla frequenza di MN e i corrispondenti indici di dispersione (SD o SEM).
La ricerca ha fornito 96 studi di cui solo 25 rispondevano ai criteri di selezione. La maggioranza degli studi evidenziava un incremento statisticamente significativo della frequenza di MN nel personale esposto agli AB, rispetto ai non esposti. La meta-analisi è stata effettuata utilizzando il programma Review Manager (RevMan 5.1) della The Cochrane Collaboration. I risultati sono stati espressi come rapporto delle medie, con lo scopo di poter combinare studi che esprimevano lo stesso end point in modalità differenti.
CONCLUSIONE
I valori di rischio relativo ottenuti (RoM 1.74 IC95% 1.30-2.33) indicano che la manipolazione di AB determina un incremento dei MN e, in virtù del già noto valore prognostico di tale biomarcatore, lo studio conferma il rischio genotossico nel personale esposto alla manipolazione di AB, rispetto ai non esposti. La manipolazione di tali farmaci coinvolge varie figure professionali e il successo degli interventi di prevenzione è legato alla conoscenza del rischio sulla salute e dei metodi disponibili per prevenire la contaminazione
Rischio genotossico da manipolazione di farmaci chemioterapici antiblastici negli operatori sanitari professionalmente esposti: revisione sistematica della letteratura e meta-analisi = Genotoxic risk in nurses handling antiblastic drugs: Systematic review of literature and meta-Analysis
No full textThere is growing concern about possible genotoxic hazards for healthcare personnel handling cytotoxic chemotherapy drugs (CCD) due to increased use in the treatment of not only neoplastic diseases. It is therefore necessary to monitor health care workers and prevent exposure. We performed a structured computer search on Pubmed/Medline for molecular epidemiological studies reporting results referring to chromosome aberration (CA) in nurses exposed to CCD. Selected studies reported average group data relative to frequency of structural/numerical CA and the corresponding measures of dispersion. We calculated the ratio of mean as a measure of effect. We conducted a meta-Analytic review of 26 studies. In most of the cases, studies showed a high frequency of CA in the exposed personnel compared to non-exposed subjects. Our study shows a statistically significant increase of CA in exposed personnel RoM=2,01 (IC95%=1,68-2,42). According to the prognostic value of CA, the studied population appears to be much more at risk to develop cancer than unexposed nurses. This finding clearly indicates the necessity to improve some steps in the administration process and nurses' awareness of genotoxic risk
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
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