1,720,965 research outputs found
History of investigation and current classification of Coronaviruses (Nidovirales: Coronaviridae) [ИСТОРИЯ ИЗУЧЕНИЯ И СОВРЕМЕННАЯ КЛАССИФИКАЦИЯ КОРОНАВИРУСОВ (NIDOVIRALES: CORONAVIRIDAE)]
No full textAn epidemic of COVID-19 (Coronavirus disease 2019) etiologically associated with the SARS-CoV-2 (Severe acute respiratory syndrome-related coronavirus 2) that occurred at the turn of 2019–2020 firstly in Wuhan (Hubei province of China) and then spread to many countries around the world rose a new wave of interest to coronaviruses. The first coronaviruses – members of the Coronaviridae family belonging to the order Nidovirales — were discovered in the first half of the last century. The first human coronavirus, HCoV-B814, was isolated in 1965 that was not preserved in available virological collections. Over the last time, old-fashioned names and terms have been overlapped. By the beginning of the XXI century coronaviruses posed a serious veterinary problem but it was believed that epidemic coronaviruses were not among highly dangerous viruses. Scientific community had to revise such views first in 2002 when SARS-CoV (Severe acute respiratory syndrome-related coronavirus) was transferred to human population in the Southeast Asia from bats, and then in 2012 when natural foci of the MERS-CoV (Middle East respiratory syndrome-related coronavirus) were found on the territory of the Arabian Peninsula. Due to an increased interest in coronaviruses, a large number of new Coronaviridae members was discovered in the first two decades of the XXI century, which required to revise its taxonomic structure several times. This review is aimed at outlining a history of investigating coronaviruses and their current classification that was shaped in early 2020 in accordance to the last recommendations of the International Committee on Taxonomy of Viruses. © 2020 Saint Petersburg Pasteur Institute. All rights reserved
Development and Evaluation of a One-Step Quantitative RT-PCR Assay for Detection of Lassa Virus
No full textLassa fever is a severe viral hemorrhagic illness caused by Lassa virus. Based on estimates, the number of LASV infections ranges from 300,000 to 500,000 cases in endemic areas with a fatality rate of 1%. Development of fast and sensitive tools for the control and prevention of Lassa virus infection as well as for clinical diagnostics of Lassa fever are crucial. Here we reported development and evaluation of a one-step quantitative RT-qPCR assay for the Lassa virus detection – LASV-Fl. This assay is suitable for the detection of lineages I-IV of Lassa virus. The limit of detection of the assay ranged from 103 copies/ml to 105 copies/ml and has 96.4% diagnostic sensitivity, whereas analytical and diagnostic specificities both were 100%. Serum, whole blood and tissue are suitable for use with the assay. The assay contains all the necessary components to perform the analysis, including an armored positive control (ARC+) and an armored internal control (IC). The study was done during the mission of specialized anti-epidemic team of the Russian Federation (SAET) in the Republic of Guinea in 2015-2018. Based on sequencing data, LASV-specific assay was developed using synthetic MS2-phage-based armored RNA particles, RNA from Lassa virus strain Josiah, and further, evaluated in field conditions using samples from patients and Mastomys natalensis rodents. © 2019 Elsevier B.V
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
Контактная атомно-силовая спектроскопия раковых клеток из эпителия желудка человека
Get PDFFor the first time, we have measured adhesion forces between normal and malignated tissues extracted from human stomach epithelium and the tip of an atomic force microscope. We have found a significant decrease (more than by an order of value) of the adhesion forces of malignated cells, and their contact stiffness, as well.Впервые измерена величина сил адгезии нормальных и раковых клеток из эпителия желудка человека к зонду атомно-силового микроскопа. Обнаружено значительное уменьшение (более чем на порядок величины) силы адгезии малигнизированных клеток и их контактной жёсткости
Contact atomic force microscopy of biological tissues
No full textThe forces of adhesion of the normal and tumor cells of the human stomach epithelium to the probe of an atomic force microscope have been measured for the first time. It is established that the adhesion and contact stiffness of malignant cells are significantly lower than those of the normal cells. © 2010 Pleiades Publishing, Ltd
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