1,720,963 research outputs found
Esercizi, Quiz e Problemi di Biologia Generale della Cellula
No full textLa pubblicazione consiste in una sequenza di 12 capitoli, ciascuno dei quali dedicato ad una specifica tematica di Biologia Cellulare che viene brevemente riassunta nei suoi concetti essenziali. Ciascun capitolo contiene test di autovalutazione per lo studente articolati nelle sezioni: frasi ad incastro, caccia all'errore, domande a scelta multipla e problemi, per ognuna delle quali, capitolo per capitolo, sono fornite le risposte corrette e le opportune spiegazioni.
Il testo costituisce un possibile utile complemento all'uso di un testo base utilizzabile per l'apprendimento delle conoscenze teoriche necessarie in un corso di Biologia Cellulare di valenza universitaria
Biologia generale e molecolare della cellula
No full textLa pubblicazione consiste in un trattato di Biologia diretto principalmente agli studenti di Medicina che può essere valido supporto anche per la preparazione di Corsi di Biologia cellulare per gli studenti di Scienze Biologiche e per i Corsi di studio di Biotecnologie Interfacoltà (Medicina, Scienze e Farmacia). Il testo è organizzato in due parti. La prima parte consta di 7 capitoli: 1) Lo stato vivente della materia, 2) Organizzazione della materia vivente nelle unità biologiche elementari, 3) La informazione biologica, 4) La storia della vita sulla Terra, 5) La dinamica della vita. Le basi molecolari, 6) Complessità e versatilità delle macromolecole, 7) La dinamica della vita. La seconda parte consta di 9 capitoli: 1) La membrana plasmatica: individualità e socialità della cellula, 2) Struttura e organizzazione dell’apparato genetico, 3) Dal genotipo al fenotipo: il braccio efferente del circuito informativo, 4) Organizzazione generale del citoplasma. 5) La compartimentalizzazione intracellulare e la specializzazione funzionale degli organelli , 6) Transazioni energetiche : fotosintesi e respirazione cellulare, 7) Controllo della espressione dell’informazione genetica: il braccio afferente del circuito informazionale, 8) La riproduzione delle unità biologiche elementari, 9) Basi cellulari della riproduzione degli organismi
A quantitative assessment of non specific pinocytosis by human endothelial cells surviving in vitro.
No full textHuman umbilical vein endothelial cells have been assayed in vitro, 24 hrs. after plating, for non specific pinocytic activity. The culture conditions were designed to minimize the exogenous stimulations of pinocytosis, such as those possibly coming from mitotic induction and chemical and contact-dependent signaling. Two different markers were used: Lucifer Yellow CH (LY), and three different preparations of horseradish peroxidase, a multiple form (type II) composed of five different isoenzymes, and two purified acidic (type VIII) and basic (type IX) isoenzymes. The uptake of LY appears to depend on both fluid-phase incorporation and non specific adsorption to the cell surface, and it shows a linear monophasic dependence on time and a linear diphasic dependence on concentration. This probe is actively chased from the cells to an extent proportional to the amount incorporated. Therefore, the endocytic index obtained from the LY incorporation data is not a reliable estimate of extracellular fluid incorporation. The three different forms of HRP share an incorporation pattern linearly dependent on both time and concentration, consistent with the classical interpretation of a simple fluid-phase mechanism of intracellular uptake; however, the rates of uptake and chase activity of the pure isoenzymes are clearly different from that of the multiple form. The observed differences are related to possible local variations in the physicochemical properties of the cell surface, which may restrict the cell surface area suitable for fluid-phase uptake of differently charged macromolecular probes
NON-SPECIFIC PINOCYTOSIS IN VITRO BY REAGGREGATED HUMAN ENDOTHELIAL CELLS: INCORPORATION OF HORSERADISH PEROXIDASE
No full textNON-SPECIFIC PINOCYTOSIS BY HUMAN ENDOTHELIAL CELLS CULTURED AS MULTICELLULAR AGGREGATES:UPTAKE OF LUCIFER YELLOW AND HORSERADISH PEROXIDASE
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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
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