1,721,036 research outputs found
SPECIALIZED FUNCTIONS OF LAMINA PROPRIA ANTIGEN-PRESENTING CELLS IN THE MAINTENANCE OF INTESTINAL IMMUNE-HOMEOSTASIS
Get PDFThe intestinal immune system is daily threatened by the exposure to potentially harmful agents, such as food antigens and the gut flora. They represent, indeed, a potent immunogenic stimulus that the immune system has to tolerate.
In the Gut-Associated Lymphoid Tissue, the cooperation and mutual interaction of specific environmental factors and peculiar populations of antigen-presenting cells renders the gut a suitable site for the maintenance of a tolerogenic milieu, where immunosuppressive mechanisms keep at bay unwanted deleterious immune responses.
The establishment of tolerance to food antigens mostly relies on the ability of specific subsets of mononuclear cells to take up antigens in the SI (Small Intestine) and to subsequently shape the immune response, which is initiated in the draining mesenteric lymph nodes.
Here, we describe a subset of resident intestinal macrophages, expressing CX3CR1, which are committed to antigen uptake. Furthermore, we show that in the absence of functional CX3CR1 receptor, which impairs the ability of these cells to sample the intestinal lumen, decreased antigen uptake and failure in the establishment of oral tolerance is observed in CX3CR1-deficient mice.
As CX3CR1+ cells are sessile and poorly able to prime T cells, we hypothesized the possibility of gap junction-mediated antigenic material transfer to CD103+ dendritic cells, which have been accounted for migratory tolerogenic cells. We show, indeed, that mononuclear cells from the SI can exchange peptides and gap-junction diffusible dyes. Furthermore, CX3CR1+ macrophages and CD103+ dendritic cells express a peculiar panel of connexins, among which connexin 43 is the most expressed.
We then generated mice lacking connexin 43 in CD11c+ cells. These mice displayed no change in the frequency and activation state of the different populations of lamina propria cells but decreased the levels of peripheral T regulatory cells at steady-state. In addition, we observed impaired establishment of oral tolerance to ovalbumin. This indicates that DC-expression of Cx43 is required for the establishment of oral tolerance. Whether this is due to a lessening in antigen transfer which impinges on the ability of CD103+ dendritic cells to prime T cells towards a tolerogenic phenotype or to other Cx43-dependent functions of SI mononuclear cells are still open questions, which need to be addressed
Alcune puntualizzazioni sul contrasto tra Cavour e Mazzini nel Risorgimento
No full textAnalisi del contrasto ideologico-politico sviluppatosi tra Cavour e Mazzini nell'ambito del processo di unificazione nazionale
Repubbliche allo specchio: Sismondi e Mazzini
No full textI rapporti tra Sismondi e Mazzini sono stati più volte oggetto di analisi. In questo saggio l'A. cerca di darne una lettura innovativa, partendo dal presupposto che Sismondi sia stato l'unico straniero (e per di più niente affatto giovane) chiamato da Mazzini a collaborare alla prima serie della "Giovine Italia". In un certo Sismondi è stato per Mazzini il termine di paragone negativo rispetto al quale formulare un nuovo repubblicanesimo. In sintesi possiamo affermare che se per Sismondi il repubblicanesimo era, secondo i canonci classici, una forma di governo, per Mazzini si trasforma in una forma di Stat
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
Maximum Likelihood Segmentation of Ultrasound Images with Rayleigh Distribution
No full textThis study presents a geometric model and a computational algorithm for segmentation of ultrasound images. A partial differential equation (PDE)- based flow is designed in order to achieve a maximum likelihood segmentation of the target in the scene. The flow is derived as the steepest descend of an energy functional taking into account the density probability function of the gray levels of the image as well as smoothness constraints. To model the gray level behavior of ultrasound images, the classic Rayleigh probability distribution is considered. The steady state of the flow presents a maximum likelihood segmentation of the target. A finite difference approximation of the flow is derived, and numerical experiments are provided. Results are presented on ultrasound medical images as fetal echography and echocardiography
Examples of Application of Ground Penetrating Radar to Investigate River Embankments
No full textGPR survey has proved a useful tool for for preliminary river embankment investigatio
Dal Risorgimento alla Seconda guerra mondiale : Formazione, trasmissione, usi pubblici del passato nell’Italia contemporanea
Get PDFInterventi relativi alla presentazione dei libri di Massimo Baioni (Vedere per credere. Il racconto museale dell’Italia unita, Roma, Viella, 2020) e di Filippo Focardi (Nel cantiere della memoria. Fascismo, Resistenza, Shoah, Foibe, Roma, Viella, 2020. Attorno a questi due libri, per certi versi complementari e in dialogo tra loro, si è svolta una discussione relativa alla memoria risorgimentale e alle memorie del fascismo, della Seconda guerra mondiale, della Resistenza e della Shoah. Al di là della storiografia e del suo ruolo nella formazione di un discorso pubblico nella penisola, il dibattito ha riguardato la formazione e trasmissione del sentimento nazionale oggi in Italia, il rapporto tra gli storici e i mezzi di comunicazione attuali, la costituzione di una memoria europea. Al centro della discussione sta insomma la questione del rapporto che abbiamo oggi con la Storia, una questione fondamentale nei lavori di Baioni e di Focardi, che possono essere entrambi considerati come due «sismografi» della percezione odierna dell’idea di nazione
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