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Влияние эндокринного дизраптора бисфенола А на качество эякулята у мужчин
Get PDFBackground: The reproductive health disorders in men are one of the urgent problems of international medicine. The prevalence of idiopathic male infertility has the highest rate. Oxidative stress, genetic factor, and endocrine disruptors are considered to be the most probable causes for the idiopathic male infertility. In this regard, studying the effect of endocrine disruptors, in particular bisphenol A on male reproductive health, becomes actual and relevant. Aims: The aim of the study was to reveal the relationship between the concentration level of bisphenol A (BPA) in seminal fluid and semen quality in men with normo- or pathozoospermia, as well as between the concentration level of bisphenol A and the level of total testosterone and estradiol in plasma. Materials and methods: 53 samples of seminal fluid of men with normo- or pathoospermia were studied. In seminal fluid the concentration of bisphenol A was determined by gas chromatography with mass spectrometry (GC-MS). The spermiological analysis was performed according to the WHO recommendations (2010) including the evaluation of sperm count/concentration, motility and morphology, and DNA fragmentation index. In addition, the concentration of total testosterone and estradiol in plasma was determined. The results were statistically processed using the Mann–Whitney U test, the correlation analysis, the paired regression method, and the ROC curves to determine the cut-off point for BPA in the seminal fluid. The results were considered statistically significant at p0.05. Results: In 100% of the ejaculate samples BPA with a median concentration of 0.15 (0.06–0.31) ng/ml was detected. Using the Spearman rank correlation coefficient, statistically significant correlations between the concentration of BPA and the total count (r=-0.330, p=0.016), concentration (r=-0.309; p=0.024), the proportion of progressively motile spermatozoa (r=-0.575; p=0.001), the proportion of spermatozoa with normal morphology (r=-0.397, p=0.003), the degree of sperm DNA fragmentation (r=0.349, p=0.025), and the concentration of total testosterone (r =-0.616; p0.001) were registered. A statistically significant inverse linear relationship (r=-0.406, p=0.003) and (r =-0.364, p=0.048) was determined by a paired linear regression between the BPA concentration in the seminal fluid and the proportion of progressively motile spermatozoa, and the total testosterone level respectively. To assess the risk of pathozoospermia, the threshold value of seminal BPA concentration was determined using the analysis of ROC-curves; the cut-off point was 0.1025 ng/ml. Conclusions: BPA in the seminal fluid influences negatively on the quality of the sperm and suppress the level of total testosterone in plasma.Обоснование. Нарушение репродуктивного здоровья мужчин является одной из актуальных проблем медицины во всем мире. При этом самой частой формой мужского бесплодия является идиопатическое. Среди наиболее вероятных причин идиопатического бесплодия называются оксидативный стресс, генетические факторы, а также эндокринные дизрапторы. В связи с этим становится актуальным изучение влияния эндокринных дизрапторов, в частности бисфенола А, на мужское репродуктивное здоровье. Цель исследования — установить связь между уровнем концентрации бисфенола А в семенной жидкости и качеством эякулята у мужчин с нормо- и патозооспермией, а также с уровнем общего тестостерона и эстрадиола плазмы крови. Методы. Исследовано 53 образца семенной жидкости мужчин с нормо- и патозооспермией. В семенной жидкости определялась концентрация бисфенола А методом газовой хроматографии с масс-спектрометрией (GC-MS). Спермиологическое исследование проводилось согласно рекомендациям ВОЗ (2010) с учетом оценки количества сперматозоидов, их подвижности и морфологии, а также индекса фрагментации ДНК сперматозоидов. Кроме того, определялся уровень концентрации общего тестостерона и эстрадиола в плазме крови. Полученные результаты были подвергнуты статистической обработке с использованием U-критерия Манна–Уитни, корреляционного анализа, метода парной регрессии, а также ROC-анализа с целью определения точки сut-off для бисфенола А в семенной жидкости. Результаты считались статистически значимыми при р0,05. Результаты. В 100% образцов эякулята был обнаружен бисфенол А со срединной концентрацией 0,15 (0,06–0,31) нг/мл. С помощью коэффициента ранговой корреляции Спирмена были обнаружены статистически значимые корреляционные связи между концентрацией бисфенола А и общим количеством сперматозоидов (r=-0,330; p=0,016), концентрацией (r=-0,309; p=0,024), и долей прогрессивно подвижных сперматозоидов (r=-0,575; p0,001), долей сперматозоидов с нормальной морфологией (r=-0,397; р=0,003), степенью фрагментации ДНК сперматозоидов (r=0,349; р=0,025) и концентрацией общего тестостерона крови (r=-0,616; р0,001). Методом парной линейной регрессии между концентрацией бисфенола А в семенной жидкости и долей прогрессивно подвижных сперматозоидов, а также уровнем общего тестостерона крови была определена статистически значимая обратная линейная зависимость — r=-0,406; р=0,003 и r=-0,364; р=0,048 соответственно. С помощью анализа ROC-кривых для оценки риска патозооспермии определено пороговое значение концентрации бисфенола А эякулята в точке cut-off — 0,1025 нг/мл. Заключение. Бисфенол А в семенной жидкости может вносить негативный вклад в качество эякулята и подавлять уровень общего тестостерона крови .
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
Author Under Sail The Imagination of Jack London, 1893-1902
No full textIn Author Under Sail, Jay Williams offers the first complete literary biography of Jack London as a professional writer engaged in the labor of writing. It examines the authorial imagination in London's work, the use of imagination in both his fiction and nonfiction, and the ways he defined imagination in the creative process in his business dealings with his publishers, editors, and agents. In this first volume of a two-volume biography, Williams traverses the years 1893 to 1902, from London's "Story of a Typhoon" to The People of the Abyss. The Jack London who emerges in the pages of Author Under Sail is a writer whose partnership with publishers, most notably his productive alliance with George Brett of Macmillan, was one of the most formative in American literary history. London pioneered many author models during the heyday of realism and naturalism, blurring the boundaries of these popular genres by focusing on absorption and theatricality and the representation of the seen and unseen. London created an impassioned, sincere, and extremely personal realism unlike that of other American writers of the time. Author Under Sail is a literary tour de force that reveals the full range of London as writer, creative citizen, and entrepreneur at the same time it sheds light on the maverick side of machine-age literature.Intro -- Title Page -- Copyright Page -- Dedication -- Contents -- Acknowledgments -- Introduction -- 1. Spirit Truth -- 2. From Absorption to Theatricality and Back Again -- 3. "I Will Build a New Present" -- 4. Sons as Authors -- 5. Fathers as Publishers -- 6. The Daughter as Author -- 7. Lovers as Authors -- 8. At Sea with the Family -- 9. Yellow News, Yellow Stories -- 10. The Return Home -- Notes -- Bibliography -- Index -- About Jay WilliamsIn Author Under Sail, Jay Williams offers the first complete literary biography of Jack London as a professional writer engaged in the labor of writing. It examines the authorial imagination in London's work, the use of imagination in both his fiction and nonfiction, and the ways he defined imagination in the creative process in his business dealings with his publishers, editors, and agents. In this first volume of a two-volume biography, Williams traverses the years 1893 to 1902, from London's "Story of a Typhoon" to The People of the Abyss. The Jack London who emerges in the pages of Author Under Sail is a writer whose partnership with publishers, most notably his productive alliance with George Brett of Macmillan, was one of the most formative in American literary history. London pioneered many author models during the heyday of realism and naturalism, blurring the boundaries of these popular genres by focusing on absorption and theatricality and the representation of the seen and unseen. London created an impassioned, sincere, and extremely personal realism unlike that of other American writers of the time. Author Under Sail is a literary tour de force that reveals the full range of London as writer, creative citizen, and entrepreneur at the same time it sheds light on the maverick side of machine-age literature.Description based on publisher supplied metadata and other sources.Electronic reproduction. Ann Arbor, Michigan : ProQuest Ebook Central, YYYY. Available via World Wide Web. Access may be limited to ProQuest Ebook Central affiliated libraries
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