1,721,797 research outputs found
Produksi Nisin Oleh Lactococcus lactis ATCC 11454 Terimobilisasi Dengan Medium Fermentasi Whey Tahu (Kajian Konsentrasi Glukosa dan Berat Bead)
Get PDFDewasa ini sedang marak penggunaan bahan kimia untuk pengawet produk pangan yang bertujuan memperpanjang umur simpan produk pangan, alternatif untuk mempertahankan kesegaran produk pangan secara aman adalah dengan penggunaan biopreservatif alami diantaranya bakteriosin yang dapat disintesis oleh bakteri asam laktat (BAL). Nisin adalah bakteriosin polipeptida yang diproduksi oleh Lactococcus lactis ATCC 11454 dan telah dikenal aman untuk mengontrol bakteri patogen dan pembusuk makanan terutama S. aureus. Salah satu hambatan yang ada dalam proses produksi nisin adalah mahalnya media yang digunakan selama produksi. Oleh karena itu, penelitian ini mencoba menawarkan solusi dalam menekan biaya produksi nisin dengan memanfaatkan limbah whey tahu sebagai medium fermentasi yang dikombinasikan dengan teknik imobilisasi dari Lactococcus lactis ATCC 11454 untuk mengoptimalkan proses fermentasinya. Tujuan dari penelitian ini adalah untuk menentukan jumlah inokulum Lactococcus lactis ATCC 11454 terimobilisasi yang digunakan dalam produksi nisin dari whey tahu dan untuk menentukan konsentrasi glukosa dalam mengoptimalkan produksi nisin oleh Lactococcus lactis ATCC 11454 terimobilisasi dari whey tahu. Penelitian ini menggunakan metode deskriptif dengan membandingkan hasil dengan literatur yang mendukung. Adapun analisa yang dilakukan meliputi analisa pH, nisin, gula reduksi dan total mikroba. Berdasarkan hasil penelitian didapatkan produksi nisin tertinggi pada konsentrasi glukosa 6% dan berat bead 7,5 gr yaitu sebesar 690 IU/ml dengan penurunan pH sebesar 2,05, total L. lactis 4,29x1015 serta konsumsi gula 4,837 % Nisin terendah diproduksi dengan fermentasi menggunakan konsentrasi glukosa 10% dan berat bead 10 gr yaitu 450 IU/ml dengan penurunan pH 2,78, total L. lactis 6,33x1012 dan konsumsi gula 9,414 %. Hasil penelitian menunjukkan bahwa berat bead dan konsentrasi glukosa dapat meningkatkan produksi nisin. Produksi nisin oleh L. lactis ATCC 11454 terimobilisasi lebih tinggi daripada sel bebas. Perlakuan terbaik dengan nisin tertinggi 690 IU/ml diperoleh pada penggunaan bead 7,5 gr/200ml dan konsentrasi glukosa 6%
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
Suitability of Lactococcus lactis subsp lactis ATCC 11454 as a protective culture for lightly preserved fish products
No full textThis study is part of strategy to control the human pathogen Listeria monocytogenes in lightly preserved fish products by using food-grade lactic acid bacteria. When the nisin-producing Lactococcus lactis subsp lactis ATCC 11454 was cultured in the same vessel as L-monocytogenes Scott A in brain-heart infusion broth (BHI) at 30-degrees C, the pathogen declined from 5x10(5) to fewer than 5 cfu ml(-1) within 31 h. The effect was not due to lactic acid inhibition. Growth and nisin production by L- lactis ATCC 11454 were investigated under the conditions of temperature and salt used for light preservation. At 5-degrees C in M17 broth, the organism grew well ans produced nisin. In an infusion of cold-smoked salmon the organism did not grow at 5-degrees C, althoigh it did at 10-degrees C. NACl up to 4% allowed for efficient growth and nisin production, while 5% NaCl resultes in very slow growth and no detectable nisin. On slices of commercial cold-smoked salmon at 10-degrees C, no net propagation pf L-lactis ATCC 11454 could be detected within 21 days. However, when salmon slices were inoculated with L- mycocytogenes at 10(4) cfu g(-1) and a 300-fold excess of washed lactococcus cells, the pathogen's population declined a half log the first 1-5 days, then increased at a rate slightly lower than that of the control not inoculated with the lactococcu
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
- …
