1,720,996 research outputs found
FLUORESCEIN CONJUGATES OF 9- AND 10-HYDROXYSTEARIC ACIDS: SYNTHETIC STRATEGIES, PHOTOPHYSICAL CHARACTERIZATION, AND CONFOCAL MICROSCOPY APPLICATIONS
No full textDifferent strategies are presented to conjugate a fluorescein moiety to 9- and 10-hydroxystearic acids (HSAs). 5-Amino-fluorescein
(5-AF) was used as a starting reagent. When reacted with acyl-chloride-modified HSAs, 5-AF gave rise to stable amide
derivatives with a 75% reaction yield. These products exhibited the typical steady-state and time-resolved fluorescence properties
of the fluorescein chromophore with absorption at 494 nm and emission at 519 nm. Flow cytometry studies confirmed the distinct
proapoptotic effect of underivatized 9-HSA on Jurkat cells and revealed a comparable ability of its amide derivative. Confocal
microscopy imaging studies showed that green fluorescence could stain intracellular membranous structures. Moreover, dual-dye
labeling with Mito Tracker Red, followed by colocalization analysis, revealed that HSA can move to the mitochondria. Thus,
fluorescent derivatives of HSA can be used to monitor the localization of these biologically active molecules in living cells
and can provide a useful tool for linking biochemical investigation with optical visualization methods. In contrast, when unmodified
HSAs were used, the reaction gave monoesterified and diesterified fluorescein derivatives. These products exhibited unusual
steady-state and time-resolved fluorescence properties with the excitation wavelength at 342 nm and the emission wavelength at
432 nm. It is shown that the synthesized HSA amides of fluorescein provide all of the typical photophysical and instrumental
advantages of this popular dye, whereas the unusual luminescence and excitation properties of the monoester and diester of
the 5-aminofluorescein would make these dyes interesting to explore as potential candidates for two photon excitation
applications
Relazione Struttura-Funzione di Polipeptidi con Attività Biologica e Processi di Riconoscimento Molecolare Studiati Mediante Tecniche Spettroscopiche
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
Marcatura di molecole biologiche a funzione antigenica per lo studio e la caratterizzazione di protocolli di vaccinoterapia in oncologia medica
No full textDendritic Cells (DCs) derived from human blood monocytes that have been nurtured in
GM-CSF and IL-4, followed by maturation in a monocyte-conditioned medium, are the
most potent APCs known. These DCs have many features of primary DCs, including the
expression of molecules that enhance antigen capture and selective receptors that guide
DCs to and from several sites in the body, where they elicit the T cell mediated immune
response.
For these features, immature DCs (iDC) loaded with tumor antigen and matured (mDC)
with a standard cytokine cocktail, are used for therapeutic vaccination in clinical trials of
different cancers.
However, the efficacy of DCs in the development of immunocompetence is critically
influenced by the type (whole lysate, proteins, peptides, mRNA), the amount and the time
of exposure of the tumor antigens used for loading in the presentation phase.
The aim of the present study was to create instruments to acquire more information about
DC antigen uptake and presentation mechanisms to improve the clinical efficacy of DCbased
vaccine.
In particular, two different tumor antigen were studied: the monoclonal immunoglobulin
(IgG or IgA) produced in Myeloma Multiple, and the whole lysate obtained from melanoma
tissues. These proteins were conjugated with fluorescent probe (FITC) to evaluate the
kinetic of tumor antigen capturing process and its localization into DCs, by cytofluorimetric
and fluorescence microscopy analysis, respectively.
iDC pulsed with 100μg of IgG-FITC/106 cells were monitored from 2 to 22 hours after
loading. By the cytofluorimetric analysis it was observed that the monoclonal antibody was
completely captured after 2 hours from pulsing, and was decreased into mDC in 5 hours
after maturation stimulus.
To monitor the lysate uptake, iDC were pulsed with 80μg of tumor lysate/106 cells, then
were monitored in the 2h to 22 hours interval time after loading.
Then, to reveal difference between increasing lysate concentration, iDC were loaded with
20-40-80-100-200-400μg of tumor lysate/106 cells and monitored at 2-4-8-13h from
pulsing.
By the cytofluorimetric analysis, it was observed that, the 20-40-80-100μg uptake, after 8
hours loading was completed reaching a plateau phase. For 200 and 400μg the mean
fluorescence of cells increased until 13h from pulsing.
The lysate localization into iDC was evaluated with conventional and confocal
fluorescence microscopy analysis. In the 2h to 8h time interval from loading an intensive
and diffuse fluorescence was observed within the cytoplasmic compartment. Moreover,
after 8h, the lysate fluorescence appeared to be organized in a restricted cloudy-shaded
area with a typical polarized aspect. In addition, small fluorescent spots clearly appeared
with an increment in the number and fluorescence intensity.
The nature of these spot-like formations and cloudy area is now being investigated
detecting the colocalization of the fluorescence lysate and specific markers for lysosomes,
autophagosomes, endoplasmic reticulum and MHCII positive vesicles
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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