1,720,957 research outputs found
Determination of opioid analgesics in hair samples using liquid chromatography/tandem mass spectrometry and application to patients under palliative care
No full textHair testing procedures allow a cumulative reflection of long-term drug abuse and are useful as a test for compliance in clinical toxicology. In the present study, liquid chromatography coupled with tandem mass spectrometry was used to determine analgesic opioid drugs in hair samples. The procedure used a simple methanolic extraction, and the evaporated extract was analyzed directly. A selective and sensitive procedure for the simultaneous determination of bisnortilidine, nortilidine, tilidine, buprenorphine, codeine, oxycodone, fentanyl, norfentanyl, hydromorphone, morphine, normorphine, oxymorphone, methadone, piritramide, and tramadol was developed and fully validated. The method fulfilled validation criteria and was shown to be sensitive, with limits of detection ranging from 0.008 to 0.017 ng/mg hair matrix, and precision ranging between 3.1% and 14.9 %. The applicability of the method was shown by analysis of authentic hair samples from patients receiving opioids for the treatment of cancer pain (eg, fentanyl was detected in concentrations up to 0.292 ng/mg, tramadol in concentrations up to 0.612 ng/mg of hair of 1 patient). Hair analysis was shown to be a complementary and useful tool in monitoring the drug-taking behavior of patients consuming opioid analgesics for the treatment of pain. In self-reports and medical records especially, the ingestion of tramadol and methadone was found to be dramatically underreported. In summary, hair analyses gave important additional information for the medical treatment of patients, the results often coming as a surprise to even the attending physicians
Anwendungen der HPLC-Triple Quadrupol Massenspektrometrie in der forensischen und klinischen Toxikologie bei der Analytik von Opioiden
No full textIn der modernen toxikologischen Analytik sind chromatographische Verfahren nicht mehr wegzudenken. Bereits seit über zwei Jahrzehnten spielen dabei die Hochleistungsflüssigchromatographie (HPLC) und die Gaschromatographie (GC), letztere meist mit Massenspektrometern (MS) gekoppelt, die wichtigste Rolle für die qualitative und quantitative Bestimmung kleinster Mengen von unterschiedlichen Wirkstoffen. Durch die Kopplung von HPLC und MS erschließen sich vielfältige neue Möglichkeiten, sowohl in Bezug auf das Spektrum der Analyten, welches mit einem einzigen Gerät erfasst werden kann, als auch auf die Empfindlichkeit. In der vorliegenden Arbeit wurden die Vorteile der HPLC-MS/MS gegenüber den herkömmlichen Verfahren der toxikologischen Analytik evaluiert und anhand von verschiedenen Anwendungsgebieten dargestellt. Dafür wurden neue Methoden zur Bestimmung von Opioiden in unterschiedlichen Körpermatrices entwickelt und die Anwendbarkeit durch die Analyse zahlreicher Realproben aus der forensischen und klinischen Toxikologie belegt. Die Untersuchung von Opiaten in Urin, Blut und Mohnprodukten ermöglichte so die Qualifizierung und Verifizierung von Markersubstanzen für den Konsum von Straßenheroin und pharmazeutischem Heroin, so dass der Konsum derselbigen unterschieden und auch klar von der unbewussten Opiataufnahme durch Mohnprodukte abgegrenzt werden kann. Dafür wurden mehr als 1000 Proben aus dem Bonner Heroinprojekt und einer eigens entwickelten Studie, dem „Mohnkuchenversuch“, aufgearbeitet und untersucht. Die Bestimmung von analgetisch wirksamen Opioiden erweiterte das Spektrum an Matrices auf Serum und Haare. In etwa 300 Proben wurden verschiedene Analgetika aus der Palliativmedizin, sowie deren Metaboliten bestimmt. Dabei wurden in vielen Fällen von der Literatur abweichende Wirkstoffspiegel festgestellt, und auch die Unterschiede von Einzelmedikation und kombinierter Schmerzmittelgabe bezüglich der eingesetzten Dosis konnten klar belegt werden. Die in der vorliegenden Arbeit entwickelten Methoden wurden nach Richtlinien der Gesellschaft für Forensische und Toxikologische Chemie (GTFCH) validiert und zeichneten sich durch hohe Empfindlichkeiten für die zu untersuchten Ergebnisse aus. Die damit ermittelten Ergebnisse konnten schlüssig interpretiert und die Vorteile der HPLC-MS/MS gegenüber herkömmlichen Analyseverfahren wie die verbesserte Sensitivität und Selektivität, die breite Anwendungspallette sowie die Einfachheit und Schnelligkeit der Analysen dargestellt werden
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
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
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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