1,720,957 research outputs found
High hydrostatic pressure activity on the disinfection of clams artificially contaminated with feline calicivirus
No full textThe contamination of shellfish with gastroenteric viruses may cause outbreaks because they are often eaten raw or under-cooked. High-hydrostatic pressure treatments have already proven to be effective in reducing high viral load in shellfish samples. The objectives are the assessment of the viral load reduction of contaminated clams using HHP treatments at different pressures and times and the study of the changes caused by these treatments in some food physical parameters. Clams were contaminated with a solution containing Feline Calicivirus; they were closed in envelopes and treated with 300, 400, 500, 600 MPa for 1, 3, 5, 7 min for every pressure value. After the treatment the residual viral titre was calculated. The texture parameters were obtained after treating clams samples at the same pressure values but only for 3 and 7 min and analysing them with a TPA test. HHP treatments of 500 and 600 MPa were sufficient to cause a total inactivation at every timelength considered while with 300 and 400 MPa after 1 min, concentrations of 1.13 and 0.55 respectively were found. In general hardness and gumminess tend to increase after the treatment whereas springiness and cohesiveness decrease a bit. HHP treatments showed good sterilization ability against FCV but it's necessary to consider that FCV has a lower resistance to disinfection than Human norovirus. Texture changes are in line with what is reported in literature
PCR, Real-Time PCR analysis on Norwalk virus direct test on artificial-contaminated foodstuff
No full textIntroduction: The most commonly used methods to determine and identify Norwalk virus are based on molecular biology. Methods: A viral extraction protocol from food samples was studied in this work using artificial contamination test. It consists of a new protocol with a phase of viral elution from the food matrix performed using an eluting solution (glycine and beef extract at 3% pH 9) and a concentration phase with polyethylene glycol 8000. To detect Noroviruses, two techniques of molecular biology, polymerase chain reaction and real-time polymerase chain reaction, were compared. At the same time, tests of direct viral identification were conducted on soft fruits and salad obtained from the market. Results: From the results obtained it was possible to evaluate how the phase of viral recovery represents an important critical point of the protocol. Conclusion: It was possible to identify a greater sensitivity of the real-time polymerase chain reaction compared with the traditional polymerase chain reaction
A comparison of proteinase K and PEG8000 on the recovery of calicivirus and norovirus in artificially contaminated food
No full textNoroviruses (NoV), transmitted mainly through the faecal-oral route, are particularly infectious and only a few particles carried by contaminated water or food are needed to cause the disease. In particular raspberries are often the cause of the onset of an outbreak. These viruses may cause large-scale outbreaks that could be limited if there was a rapid detection of the source of infection. The aim of this study is to compare the results of a method for viral detection in foodstuffs using proteinase K, a serine protease, with one that uses PEG8000 in order to assess which one provides the highest viral recovery. Mixed berries were artificially contaminated with a viral solution – feline calicivirus (FCV) or NoV – and they were analysed with the two methods for the elution of viral particles. In tests with FCV the method with proteinase K was able to obtain recovery percentages on average about three times higher than with PEG8000 (68.297 vs. 23.989). The difference between the two recoveries is statistically significant, whereas in tests with NoV, even if the protocol with proteinase K provided the best results the gap between the two methods isn't statistically significant. The proteinase K protocol obtained better recoveries in tests with both FCV and NoV. This method has the potential to become the official standard technique for the detection of viruses in food matrices
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
Study on the inactivation of enteric viruses by oxidazing compound and high-hydrostatic pressures. Development of recent methods for the viral detection in contaminated food samples.
No full textI virus che causano gastroenteriti, come il Norovirus, costituiscono un problema a livello sanitario mondiale. Durante il periodo di dottorato mi sono interessato dell'inattivazione di questi virus tramite perossido di idrogeno e alte pressioni idrostatiche; inoltre ho svolto prove per valutare l'efficacia di diversi metodi di rilevamento di tali virus in campioni alimentari. I risultati ottenuti per quanto riguarda l'inattivazione sia con perossido di idrogeno che con le alte pressioni si sono rivelati particolarmente interessanti ed è stato possibile ottenere inattivazioni totali anche a basse concentrazioni di disinfettante e a basse pressioni. La valutazione dei metodi di rilevamento ha dimostrato la maggiore efficienza di un protocollo, che utilizza la proteinasi K, per l'eluizione del virus dalla matrice alimentare.Viruses causing gastroenteritis, like Norovirus, are a great problem for health all over the world. During the PhD period I studied the inactivation of these viruses using hydrogen peroxide and high-hydrostatic pressures; moreover I evaluated the efficacy of different methods for the detection of enteric viruses in food samples. The results obtained for the inactivation with hydrogen peroxide and high-hydrostatic pressure are very interesting and it was possible to obtain total inactivations even at low disinfectant concentration and at low pressures. The evaluation of detection methods has shown the higher efficacy of a protocol, which involves proteinase K, to elute the viral particles from the food matrix
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