Surface characterization of human serum albumin and sodium perfluorooctanoate mixed solutions by pendant drop tensiometry and circular dichroism

The interfacial behavior of mixed human serum albumin (HSA)/sodium perfluorooctanoate (C8FONa) solutions is examined by using two experimental techniques, pendant drop tensiometry and circular dichroism spectroscopy. Through the analysis of the surface tension of the mixed solutions, surface competitive adsorption at the air-water interface between C8FONa and HSA is detected. The dynamic adsorption curves exhibit the distinct regimes in their time-dependent surface tension. The nature of these regimes is further analyzed in terms of the variation of the molecules surface areas. As a consequence, a compact and dense structure was formed where protein molecules were interconnected and overlapped. Thus, a reduction of the area occupied per molecule from 100 to 0.2 nm2 is interpreted as a gel-like structure at the surface. The presence of the surfactant seems to favor the formation of this interfacial structure. Finally, measurements of circular dichroism suggests a compaction of the protein due to the association with the surfactant given by an increase of α-helix structure in the complexes as compared to that of pure protein.Fil: Messina, Paula Verónica. Universidad de Santiago de Compostela; España. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Química del Sur. Universidad Nacional del Sur. Departamento de Química. Instituto de Química del Sur; ArgentinaFil: Prieto, Gerardo. Universidad de Santiago de Compostela; EspañaFil: Dodero, Veronica Isabel. Universidad de Santiago de Compostela; España. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Química del Sur. Universidad Nacional del Sur. Departamento de Química. Instituto de Química del Sur; ArgentinaFil: Cabrerizo-Vilchez, M.A.. Universidad de Granada. Facultad de Ciencias; EspañaFil: Maldonado Valderrama, J.. Universidad de Granada. Facultad de Ciencias; EspañaFil: Ruso, Juan M.. Universidad de Santiago de Compostela; EspañaFil: Sarmiento, Félix. Universidad de Santiago de Compostela; Españ

50 Years of Cetacean Strandings Reveal a Concerning Rise in Chilean Patagonia

Indexación ScopusCetacean strandings (CS) have been reported in increasing numbers in coastal areas worldwide. Although the causes of these strandings are unknown, a number of anthropogenic and environmental factors have been suggested. This paper aims to characterize CS patterns and describe their fine-scale spatiotemporal dynamics. We analysed spatial and spatiotemporal CS patterns in Chile from January 1968 to January 2020. We identified a total of 389 CS events affecting eight cetacean families, 21 genera, and 35 species, which represent more than 85% of the reported species richness for the country. Most CS events (94.1%) were single (i.e., ≤two individuals). There were also 18 mass stranding (three to 24 individuals, 4.1%) and nine unusually large mass stranding events (>25 individuals, 2%). Purely spatial tests showed CS events appearing in random occurrence along the Chilean coast. Local tests for spatio-temporal clusters, however, identified a greater number of hotspots reported in the southernmost part of the country, namely, Chilean Patagonia. Specifically, significant spatio-temporal clusters were identified and defined as containing three or more individuals within a two-month period as a focal coastal event (<1 km radius). It is a cause of concern that CS events in Chile have been increasing consistently over the last decades, and although we were not able to identify their causes, we are able to highlight the importance of changes in climate conditions and of an increase in monitoring activities as primary drivers for such patterns, particularly important in Chilean Patagonia. © 2020, The Author(s).https://www-nature-com.recursosbiblioteca.unab.cl/articles/s41598-020-66484-

Fuzzy Group Models for Adaptation in Cooperative Information Retrieval Contexts

Cooperation in information retrieval contexts can be used to share query results inside groups of individuals with common objectives, provided that all of them are aware of each other. The strength of the social relationships between group members is in most cases a matter of comparative degree, and thus relationships can be modelled through fuzzy conceptual associations. These associations can then be used to implement personalized features, aimed at improving the interaction of the user with the query tool. In this paper, an approach to modelling imprecise relationships between users in the context of information retrieval is described, along with a concrete case study implemented as a wrapper of a conventional search engine, using a fuzzy database to store the model of the group members

The Role of Vague Categories in Semantic and Adaptive Web Interfaces

Current Semantic Web technologies provide a logic-based framework for the development of advanced, adaptive applications based on ontologies. But the experience in using them has shown that, in some cases, it would be convenient to extend its logic support to handle vagueness and imprecision in some way. In this paper, the role of vagueness in the description of Web user interface characteristics is addressed, from the viewpoint of the design of adaptive behaviors that are connected to such descriptions. Concretely, vague descriptions combined with quantified fuzzy rules and flexible connectors are described, and their usefulness is illustrated through preference modeling, filtering and adaptive linking scenarios