1,721,005 research outputs found
Dentinal thickness modifications after manual and mechanical instrumentation with Ni-Ti files.
No full textAβP1-42 incorporation and channel formation in planar lipid membranes: the role of cholesterol and its oxidation products
No full textAmyloid beta peptide (AP) is a natural peptide, normally released into the cerebrospinal fluid (CSF), that plays a key role in Alzheimer’s disease. The conversion of the peptide from a native soluble form to a non-native and often insoluble form, such as small and large aggregates, protofibrils and fibrils of AP appears to be implicated in the pathogenesis of AD. Although the molecular mechanisms of AP neurotoxicity are not fully understood, a large body of data suggests that the primary target of amyloid peptides is the cell membrane of neurons, that may modulate the structural and functional conversion of AP into assemblies involved in pathological processes. In our study, we provide a systematic investigation of AP1-42’s ability to incorporate and form channel-like events in membranes of different lipid composition and focus on cholesterol and its oxidation products. We propose that cholesterol and its oxidation products can be considered neuroprotective factors because a) by favouring AP1-42 insertion into membranes, the fibrillation/clearance balance shifts toward clearance; b) by shifting channel selectivity toward anions, the membrane potential is moved far from the threshold of membrane excitability, thus decreasing the influx of calcium into the cell
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
Aldo Li Bianchi, Maria Laura Galvano, Residenza unifamiliare, Piana degli Albanesi (Palermo)
No full textVariations 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
Ancillary services markets in europe: Evolution and regulatory trade-offs
No full textThe generating power mix has deeply changed in the last years. Especially in Europe, the electric systems are evolving towards a more decentralized architecture, widely penetrated by renewable and distributed energy resources. These resources usually present less predictability and fast dynamics. To avoid jeopardizing the power system, they should be effectively included in the Ancillary Services Markets (ASMs), which procure the resources for balancing and safely dispatching the system. This work presents a meta-analysis of the evolution of ASMs and the underlying regulatory trade-offs. The evolutions are analyzed modularly to clearly investigate the benefit of each one. The analysis aims to provide an evaluation of each trend regarding the architecture, the services, and the products of the ASMs, based on the level of agreement of the two main counterparties: the system operator who manages the system and the Balancing Services Provider that delivers the service. The outcome is a ranking of the possible regulatory evolutions, with the win–win situations at the top and the cases that imply drawbacks for a counterparty at the bottom. The ranking can represent a guideline for regulatory authorities as well as market operators or players to realize effective market arrangements. Finally, a survey of European countries describes the effort of each one towards each evolution
Cisplatin handover between copper transporters: the effect of reducing agents
No full textCopper (Cu) transporters emerged as key factors at the basis of the biological response to antitumor platinum (Pt) drugs, which are among the most potent and broadly used chemotherapeutics. ATP7A and ATP7B (the Menkes and Wilson disease proteins, respectively) appear to be implicated in promoting tumor cell resistance to cisplatin. Cu-ATPases could bind the drug and, with the alleged involvement of the chaperone ATOX1, contribute to cell detoxification and survival. Here, we report the spectroscopic characterization of cisplatin binding to ATOX1 and MNK1, the first metal-binding domain of ATP7A, in the presence of the physiological reducing agent glutathione, a sulfur-containing molecule responsible for the majority of Pt detoxification in the cytosol. Under conditions mimicking the cellular environment, we show that cisplatin transfer from ATOX1 to MNK1 does not occur at a detectable rate. These results appear to contradict other literature data which, however, were obtained in the presence of exogenous reducing agents such as tris(2-carboxyethyl)phosphine (TCEP) having good coordinating ability for soft metal ions (such as Pt) and strong trans-labilizing effect. A better understanding of Pt drug processing by Cu trafficking proteins under physiological conditions may help to answer key issues, such as drug availability in tumor cells and resistance
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