1,721,079 research outputs found
A modified culture medium for improved isolation of marine vibrios
Full text linkMarine Vibrio members are of great interest for both ecological and biotechnological research, which often relies on their isolation. Whereas many efforts have been made for the detection of food-borne pathogenic species, much less is known about the performances of standard culture media toward environmental vibrios. We show that the isolation/enumeration of marine vibrios using thiosulfate-citrate-bile salts-sucrose agar (TCBS) as selective medium may be hampered by the variable adaptability of different taxa to the medium, which may result even in isolation failure and/or in substantial total count underestimation. We propose a modified TCBS as isolation medium, adjusted for marine vibrios requirements, which greatly improved their recovery in dilution plate counts, compared with the standard medium. The modified medium offers substantial advantages over TCBS, providing more accurate and likely estimations of the actual presence of vibrios. Modified TCBS allowed the recovery of otherwise undetected vibrios, some of which producing biotechnologically valuable enzymes, thus expanding the isolation power toward potentially new enzyme-producers Vibrio taxa. Moreover, we report a newly designed Vibrio-specific PCR primers pair, targeting a unique rpoD sequence, useful for rapid confirmation of isolates as Vibrio members and subsequent genetic analyses
Distribution of Lanthanides in Mediterranean Coastal waters
No full textDistribution and behaviour of the whole lanthanide series and yttrium in both seawater column and suspended particulate matter were investigated in coastal water located in the Central Mediterranean Sea. An area characterized by high anthropic pressure, atmospheric fallout and river input due to drainage of little local watersheds was selected. Water masses were discriminated with respect to both surrounding and depth and in relation to the processes occurring at the solid-liquid interface.
We found that yttrium and Rare Earth Elements in the labile fraction of the suspended particulates result from the mixing between lithogenic material from the Sicilian basin and detrital material of Sahara origin. Y/Ho and Ce/La ratios, Ce anomalies, shape and amplitudes of tetrad effects calculated in both dissolved phase and suspended matter indicates that heavier Rare Earth (from Dy to Lu) mainly occur as organic complexes in near shore waters whereas, light and intermediate Rare Earths (From La to Ho) in the outer waters are ruled by scaveging processes onto surface of suspended matter.
The behaviour of these trace elements is explained in terms of lanthanides sorption into Mn-Fe oxyhydroxide surfaces and under solution complexation. In particular, for deep water layers the found low apparent distribution coefficients for the heaviest REE and high dissolved organic matter concentration indicate surface complexation processes according to an outer sphere coordination mechanism
Quantitative evaluation of Lanthanide release to seawater during sinking of atmospheric Fe-rich particles
No full text3D collagen matrix improves islets of Langerhans differentiation and function
No full textThe importance of preserve cell-cell contact
and cell-matrix interaction are both
fundamental for maintain the differentiation
state. We use both standardized method of
isolation and culture in 3D matrix which
improves islet cell survival and function for
more than one week in colture
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
GENE STRUCTURE, DIFFERENTIAL EXPRESSION AND PHYLOGENETIC ANALYSIS OF THE METALLOTHIONEIN GENE FAMILY OF THE SEA URCHIN PARACENTROTUS LIVIDUS
No full textMetallothioneins (MT) are small and cysteine-rich proteins that bind metal ions such as zinc, copper, cadmium, and nickel1. Several functions were proposed for these peptides, ranging from toxic metal protection to physiological metal homeostasis, free radical scavenging, oxidative stress protection, antiapoptotic defense, control of the redox status of the cell and also roles during development. Previously, we reported the identification of five different MT homologues (PlMT4-8) from the Mediterranean sea urchin species P. lividus2. In order to shed some light on MT gene structure and evolution, we cloned seven P. lividus MT genes, comparing them to Echinodermata and Chordata genes3. Moreover, we performed a phylogenetic analysis of newly identified MTs from different classes of echinoderms and from the most ancient chordates, highlighting the relationships between them. Since MTs have multiple roles in the cells, we performed RT-qPCR and in situ hybridization experiments to understand better MT functions in sea urchin embryos. Results showed that the expression of MTs is regulated throughout development in a cell type-specific manner and in response to various metals3. The MT7 transcript is expressed in all tissues, especially in the stomach and in the intestine of the larva, but it is less metal-responsive. In contrast, MT8 is ectodermic and rises only at relatively high metal doses. MT5 and MT6 expression is highly stimulated by metals in the mesenchyme cells. Our results suggest that the P. lividus MT family originated by gene duplications and evolved developmental and environmental sub-functionalization. A preliminary in silico promoter analysis showed interesting similarities and differences among these genes
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
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