1,721,192 research outputs found
Biomolecular Corona Associated with Nanostructures: The Potentially Disruptive Role of Raman Microscopy
Full text linkWhen nanostructures and other materials are exposed to biological fluids, they are immediately covered by a layer of biological molecules, which is typically referred to as a “biomolecular corona” (BC). This represents the first component of a material that interacts with biological systems, so characterizing the composition and the dynamic evolution of BC is essential for predicting the interactions of materials and living organisms. This review provides an analysis of current BC characterization techniques, with particular attention to nanostructures involved in biomedical applications. The influence on cell–nanostructure interactions is assessed and the advantages and limitations of each technique are discussed and compared. An in-depth analysis of Raman microscopy, a relatively unexploited tool with great potential in the characterization of BC, is then conducted. Raman microscopy can be used to analyze a vast amount of specimens without the need for staining, and can provide analysis on a spatial scale of hundreds of nanometers: it may thus represent a potentially disruptive tool for the characterization of BC, as it overcomes many of the limitations posed by current techniques
NIVEAUX ENZYMATIQUES (GOT ET LDH) ET CAPACITÉ FECONDANTE DE LA SEMENCE DE LAPIN.
No full textUne recherche préliminaire a été effectuée sur la semence de 8 lapins males de race Néozélandaise blanche, (trois prélèvements chaque male et 110 inséminations), pour établir si les niveaux de GOT et de LDH, dans la semence et dans le plasma séminal, pouvaient constituer des éléments valables pour évaluer la capacité fécondante des éjaculats. Les résultats ont démontré que le niveau de la GOT dans le plasma, surtout si on le rapporte au taux protéique, est en corrélation négative, et significative, avec la fertilité, (r=-0,45). Le contenu de cet enzyme, considéré en sens absolu, même s’il est un peu moins corrélé avec la fertilité, peut en moyenne se répéter (0,25), et on peut donc le considérer comme un indice d’évaluation même a des fins de sélection
Effectiveness of connected legislators
No full textImportant work has been done to measure legislative effectiveness in the U.S. Congress and to explain the individual characteristics that drive it. Much less attention, however, has been devoted to study the extent to which legislative effectiveness depends on the legislators' social connections. We address this issue with a new model of legislative effectiveness that formalizes the role of social connections, and we test its predictions using the network of cosponsorship links in the 109th–113th Congresses. We propose a new empirical strategy that addresses network endogeneity by implementing a two-step Heckman correction based on an original instrument: the legislators' alumni connections. We find that social connections are a significant determinant of legislative effectiveness. We also study the influence of legislators' characteristics in shaping the network effects. In doing so, we provide new insights into how social connectedness interacts with factors such as seniority, partisanship, and legislative leadership in determining legislators' effectiveness
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
Antioxidants and Nanotechnology: Promises and Limits of Potentially Disruptive Approaches in the Treatment of Central Nervous System Diseases
Full text linkMany central nervous system (CNS) diseases are still incurable and only symptomatic treatments are available. Oxidative stress is suggested to be a common hallmark, being able to cause and exacerbate the neuronal cell dysfunctions at the basis of these pathologies, such as mitochondrial impairments, accumulation of misfolded proteins, cell membrane damages, and apoptosis induction. Several antioxidant compounds are tested as potential countermeasures for CNS disorders, but their efficacy is often hindered by the loss of antioxidant properties due to enzymatic degradation, low bioavailability, poor water solubility, and insufficient blood–brain barrier crossing efficiency. To overcome the limitations of antioxidant molecules, exploitation of nanostructures, either for their delivery or with inherent antioxidant properties, is proposed. In this review, after a brief discussion concerning the role of the blood–brain barrier in the CNS and the involvement of oxidative stress in some neurodegenerative diseases, the most interesting research concerning the use of nano-antioxidants is introduced and discussed, focusing on the synthesis procedures, functionalization strategies, in vitro and in vivo tests, and on recent clinical trials
Recommended from our members
Influencing connected legislators
Full text linkThis paper studies how interest groups allocate campaign contributions when congressmen are connected by social ties. We establish conditions for the existence of a unique Nash equilibrium in pure strategies for the contribution game and characterize the associated allocation of the interest groups’ moneys. While the allocations are generally complex functions of the environment (the voting function, the legislators’ preferences, and the social network topology), they are simple, monotonically increasing functions of the respective legislators’ Katz-Bonacich centralities. Using data on the 109th–113th Congresses and on congressmen’s alumni connections, we estimate themodel and find evidence supporting its predictions
- …
