1,720,985 research outputs found
Evaluation of the effects of photonic decontamination on reduction of Salmonella and Campylobacter and a comparative transcriptomics analysis following its application on Salmonella Infantis
Get PDFRecently, there has been an increase in research into new methods responding to the unsuccessful efforts in reducing foodborne pathogen infections associated with poultry products such as Salmonella and Campylobacter. With the looming concern of antibiotic-resistant bacteria surviving past the current antimicrobial interventions used in poultry processing along with consumer concerns and environmental impacts of the overuse of chemicals on poultry products, novel antimicrobial intervention methods have become an increasingly popular topic of conversation. The first chapter reviews published literature on these topics. Developing an effective method for reducing foodborne pathogens in animal products while preserving meat quality and application efficiency is an important topic of research. To address this, in the second chapter, we evaluated the efficacy of photonic decontamination on whole chicken wings and tenders inoculated with Salmonella and Campylobacter. Treatments included evaluating photonic decontamination alone, the inclusion of chemical antimicrobial dips with and without photonic decontamination treatment, and photonic decontamination on multiple parts simultaneously. Photonic decontamination alone and in combination with chemical dips was able to significantly reduce Salmonella and Campylobacter on both wings and tenders. Additionally, in the third chapter, we focused on elucidating the molecular basis of photonic decontamination using comparative transcriptomics analysis of Salmonella Infantis. Comparisons were made between a 100-voltage treatment and no treatment, a 200-voltage treatment and no treatment, and between a 100-voltage treatment and a 200-voltage treatment. Our results identified the list of differentially expressed genes with identified roles relating to response to light-induced cell damage, oxidative stress response, transcriptional regulation following pulsed light exposure, and stress resistance
Ethanolamine Utilization Contributes to Proliferation of <i>Salmonella enterica</i> Serovar Typhimurium in Food and in Nematodes
No full textABSTRACT
Only three pathogenic bacterial species,
Salmonella enterica
,
Clostridium perfringens
, and
Listeria monocytogenes
, are able to utilize both ethanolamine and 1,2-propanediol as a sole carbon source. Degradation of these substrates, abundant in food and the gut, depends on cobalamin, which is synthesized
de novo
only under anaerobic conditions. Although the
eut
,
pdu
, and
cob
-
cbi
gene clusters comprise 40 kb, the conditions under which they confer a selection advantage on these food-borne pathogens remain largely unknown. Here we used the luciferase reporter system to determine the response of the
Salmonella enterica
serovar Typhimurium promoters P
eutS
, P
pocR
, P
pduF
, and P
pduA
to a set of carbon sources, to egg yolk, to whole milk, and to milk protein or fat fractions. Depending on the supplements, specific inductions up to 3 orders of magnitude were observed for P
eutS
and P
pduA
, which drive the expression of most
eut
and
pdu
genes. To correlate these significant expression data with growth properties, nonpolar deletions of
pocR
, regulating the
pdu
and
cob
-
cbi
genes, and of
eutR
, involved in
eut
gene activation, were constructed in
S
. Typhimurium strain 14028. During exponential growth of the mutants 14028Δ
pocR
and 14028Δ
eutR
, 2- to 3-fold-reduced proliferation in milk and egg yolk was observed. Using the
Caenorhabditis elegans
infection model, we could also demonstrate that the proliferation of
S
. Typhimurium in the nematode is supported by an active ethanolamine degradation pathway. Taking these findings together, this study quantifies the differential expression of
eut
and
pdu
genes under distinct conditions and provides experimental evidence that the ethanolamine utilization pathway allows salmonellae to occupy specific metabolic niches within food environments and within their host organisms.
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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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