1,721,137 research outputs found
In Vivo Analysis of Gentamicin in the Inner Ear After Local or Systemic Delivery
No full text2024Two new and highly sensitive liquid chromatography techniques were developed to detect and quantify the four major C-subtypes of gentamicin in microliter samples of artificial perilymph or perilymph collected from mice. The new ultra-high-performance liquid chromatography coupled with tandem mass spectrometry (UHPLC-MS/MS) method and high-performance liquid chromatography with fluorescence detection (HPLC-Fl) assays allowed the simultaneous detection and quantification of gentamicin subtypes, with the HPLC-Fl showing superior sensitivity, speed, and suitability for perilymph samples. The HPLC-Fl assay was validated according to USP guidelines and demonstrated excellent linearity, specificity, precision, and accuracy for detecting gentamicin in the perilymph, with a detection limit of ≤0.2 ng/mL for the major C-subtypes of gentamicin. Thus, it is a highly efficient tool for measuring drug levels in small biological volumes. The HPLC-Fl technique was used to quantify gentamicin C-subtypes concentrations in murine perilymph and serum following local (intratympanic) and systemic (intraperitoneal) administration. The data obtained was used to determine the pharmacokinetics of gentamicin in perilymph and obtained crucial insights into how gentamicin is absorbed and distributed in the perilymphatic space before clearance from this space in the murine inner ear. The pharmacokinetic profile of gentamicin in murine perilymph revealed that its concentration peaks within an hour after intratympanic administration and then declines rapidly. Gentamicin C1 exhibited the fastest clearance from perilymph, while C2 (most ototoxic subtype) or C2a was retained for a longer duration in the perilymph. In contrast, after intraperitoneal administration, gentamicin concentrations in perilymph peaked more slowly, with a half-life of approximately four hours and complete elimination from the perilymph within 13 hours. The most ototoxic subtype, C2, had the highest concentration and a longer mean residence time compared to C1.
Following intratympanic administration, the level of gentamicin in the serum was extremely low. The most ototoxic subtype C2, had the highest level in the serum, and C1 had the lowest. After intraperitoneal administration, gentamicin levels peaked immediately in the serum, followed by a rapid decline. C2 maintained the highest concentration in the serum, posing a potential risk of ototoxicity and nephrotoxicity.
These findings have therapeutic implications for treating inner ear disorders, such as Ménière’s disease. Intratympanic administration allows for higher drug concentrations directly at the site of action, offering potential benefits for targeting the vestibular hair cells, particularly for vertigo management. However, at higher concentrations, this delivery method increases the risk of cochleotoxicity. This study is significant as it highlights the distinct pharmacokinetic profiles of each C-subtype, which is critical for optimizing drug delivery strategies for inner ear disorders, offering insights into how to achieve therapeutic efficacy while minimizing the risk of ototoxicity
India’s war on COVID-19: how the government is turning marginalised citizens into suspected enemies and criminals
No full textIn many of Narendra Modi’s speeches on tackling the spread of COVID-19, the Indian Prime Minister has employed a set of war-time metaphors to direct the nation’s response. Here Shreshtha Das (Independent Researcher, New Delhi) argues how this linguistic approach has turned citizens from some of the country’s marginalised groups into suspected enemies and criminals, against whom the wrath of the state and the society has been unleashed
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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