1,720,956 research outputs found
Molecular markers of hepatocellular carcinoma: RT-PCR study of uPA, uPAR and t-PA mRNAs.
No full textRapid and robust confirmation and quantification of 11-nor-Δ9-tetrahydrocannabinol-9-carboxylic acid (THC-COOH) in urine by column switching LC-MS-MS analysis
No full textA method for the rapid and robust confirmation of 11-nor- 9-tetrahydrocannabinol-9-carboxylic acid (THCA) in urine involving
basic hydrolysis with NaOH and direct injection of the hydrolysate in a column-switching LC-MS-MS system was developed and validated. THCA-d3 was used as internal standard. Detection was performed in negative-ion mode bymonitoring the tran-sitions from the [M-CO2]- ionm/z299.2!245.2 and andm/z299.2!191.1 that were found to provide a better signal-to-noise ratio than the transition from the pseudomolecular ion atm/z343. The high sensitivity of detection enabled the injection of a small volume (10ml) of the NaOH hydrolysate which, together with the applied column switching system, proved to confer ruggedness to themethod and to avoid the deterioration of the instrumental apparatus despite the large amount of inorganic ions in the hydrolysate. The LLOQ was established at 5ng/ml, and the LLOD was calculated as 0.2ng/ml (S/N =3). The method was submitted to thorough validation including evaluation of the calibration range (5–500ng/ml), accuracy and precision, ma-trix effects, overall process efficiency, autosampler stability, carryover and cross-talk, and 10-times reduction of sample vol-ume (0.1ml). Proof of applicability was obtained by direct comparison with the reference GC-MS method in use in the lab (the R2 between the two methods was 0.9951)
Prevalence of drug abuse among workers: Strengths and pitfalls of the recent Italian Workplace Drug Testing (WDT) legislation
No full textBACKGROUND:
In 2008 a Workplace Drug Testing (WDT) law became effective in Italy for workers involved in public/private transportation, oil/gas companies, and explosives/fireworks industry with the aim to ensure public safety for the community.
AIMS:
To examine and elaborate WDT data collected on a large group of workers (over 43,500) during March 2009-February 2010 in order to highlight pros and cons and to draw suggestions for policies in the field.
SETTING:
Northern Italy.
METHODS:
After ≤24h notification, workers provided a urine sample screened for opiates, methadone, buprenorphine, cocaine, amphetamines, ecstasy, and cannabinoids (THC) by immunoassay. Positives were confirmed by GC-MS.
RESULTS:
The positive rate was 2.0%, THC being most frequent drug (1.3%; cocaine, 0.4%; opioids, 0.3%). 6.9% of the positive workers tested positive for ≥2 classes (most often THC+cocaine). Gender ratio and mean age were significantly lower in positives (F/M=0.007; 35.5±8.3years) than negatives (0.016 and 40.7±9.5, respectively). No decline in rates of positives and an increase of diluted samples over time were observed. The highest rates of positives were detected when sampling was performed just before/after week-end and during morning hours. Possible correlation between job type and drugs used were observed (e.g. more cocaine positives among road vehicle-drivers than among lift truck-drivers). Declared use of medicine/illicit drugs during the preceding week showed that illicit drug use was likely not always detected in urine and that almost 4% workers declared use of medicine drugs possibly affecting performance.
CONCLUSIONS:
This survey enabled to evidence relevant pitfalls of the law and to define strategies to improve the outcomes of WDT policies
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe 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
Get PDF“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
Get PDFWe 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
Get PDFWe 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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