1,720,966 research outputs found
Characterisation and use in food matrices of Lactobacillus casei group strains
Full text linkSeveral strains belonging to L. casei group, from international collections and universities (University of Udine, University of Basilicata, University of Molise, University of Stellenbosch-South Africa, etc.), were selected. All strains were then subjected to technological characterization and the study of safety traits. Specifically it has been evaluated: their ability to growth at different temperatures or pH values and different concentrations of NaCl or ethanol; ability to produce biogenic amines, by qualitative analysis and the search of genes involved in their production (hdc, agdi, odc and tyrdc); presence of gene implicated in the production of ethyl carbamate (arcABC genes); ability to produce bacteriocins and monoamine oxidase; antibiotic resistance; hemolytic activity.
After that, the effect of anaerobic, aerobic, respiratory and acidic condition of growth on the cellular structure was investigated. Strains previously selected were analysed using Transmission Electron Microscopy (TEM). Due to the results obtained during this study, the project focused on assessing the effect of two conditions of adaptation (anaerobic and respiratory) and technological stress (milk fermentation) applied to two selected strains, previously identified as belonging to the species L. casei and L. paracasei. The following analysis were carried out: fermentative capabilities of the strains; samples shelf life; antibiotic resistance; hemolytic activity; bacteriocins production; competition with pathogens; resistance of the stressed cells to in vitro digestion. In the simulated gastro-intestinal tract the viable but non-colturable cells (VBNC) were also investigated. Also the proteolysis in fermented milk and the antimicrobial ability of the soluble fraction have been further investigated.
Moreover, the study was also aimed at evaluating the activity into salami of a selected strain of L. casei adapted in the two different conditions (anaerobic and respiratory). The following characteristics were analysed: fermentative capabilities of the strain; evaluation of the chemical/physical parameters (aw, pH, color, weight loss); changes in salami micro - flora depending on inocula; presence during the ripening of the inoculated strain (DGGE); antioxidant activity and volatile molecules profile (GC-MS / SPME); proteolysis (SDS - page); evaluation of VBNCCeppi appartenenti all’L. casei group, provenienti da collezioni internazionali e universitarie (Università di Udine, Università della Basilicata, Università del Molise, Università di Stellenbosh-Sud Africa, ecc), sono stati selezionati per la sperimentazione. Tutti i ceppi sono stati poi sottoposti a caratterizzazione tecnologica e alla valutazione della loro salubrità. In particolare sono state valutate: le loro abilità di crescita a diverse temperature, diverse concentrazioni di NaCl e etanolo, e a diversi pH; capacità di produrre ammine biogene, sia qualitativamente, sia ricercando i geni coinvolti nella loro produzione (hdc, agdi, odc e tyrdc), ed etil - carbammato (geni arcABC); capacità di generare batteriocine e mono-ammino ossidasi; resistenza agli antibiotici; attività emolitica.
Dopo di che è stato studiato l’effetto della crescita in condizioni di anaerobiosi, aerobiosi e respirazione abbinata a pH acido (3.2) sulla struttura cellulare. Ceppi selezionati da studi precedenti, sono stati analizzati tramite Transmission Electron Microscopy (TEM). Dagli esiti conseguiti, il progetto si è quindi focalizzato sulla valutazione dell’effetto di due delle tre condizioni di adattamento (anaerobiosi e respirazione) e di stress tecnologici (fermentazione del latte) applicati a due ceppi selezionati e precedentemente identificati come appartenenti alle specie L. casei e L. paracasei. Sono state studiate le seguenti caratteristiche: capacità fermentative dei ceppi; shelf – life dei campioni; antibiotico resistenza; attività emolitica; produzione di batteriocine; capacità antimicrobica della frazione solubile del latte; competizione con patogeni (co-inoculo ceppi selezionati con Listeria monocytogenes ATCC7644, Staphylococcus aureus DSM 4910, Escherichia coli DSA, Salmonella enteritidis DSA e Bacillus cereus DSA); resistenza alla digestione in vitro. Nel tratto gastro-intestinale simulato è stata svolta anche la ricerca di cellule viable but not culturable (VBNC). Successivamente sono state studiate l'attività proteolitica nel latte fermentato e le capacità antimicrobiche della frazione solubile del latte.
Inoltre, l’attività di ricerca si è rivolta alla valutazione dell'attività fermentativa di un ceppo selezionato di L. casei inoculato in salami e adattato nelle due diverse condizioni. Sono state valutate le seguenti caratteristiche: valutazione di parametri chimico/fisici dei salami (aw, pH, colore, perdita di peso); cambiamenti nella flora microbica all’interno dei salami a seconda dell’inoculo;presenza durante la maturazione del ceppo inoculato (DGGE); attività antiossidante e profilo delle molecole volatili (GC-MS/SPME); proteolisi (SDS – page); valutazione delle cellule viable but not culturable (VBNC
Effects of oxidative stress exposure on mucus binding properties and antibiotic resistance in L. casei group strains
No full text
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe 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
Full text link“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
Full text linkWe 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
Full text linkWe 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
- …
