1,721,027 research outputs found
Relationship between volume expansion, solvent-power, and precipitation in GAS processes
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Influence of polymer structure upon active-ingredient loading: a Monte Carlo simulation study for design of drug-delivery devices
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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
Molecular Dynamics Simulations of Aqueous Systems at the Solid-Liquid Interface
Full text linkInterfacial water properties determine a number of phenomena in geology, biological systems, and ion-exchange processes. The behavior of water at the solid-liquid interface plays an important role in multiple applications including water desalination membranes, porous materials used in radioactive ion separations, and in the structure-function relationship in ion channels and biological membranes. Understanding the properties of interfacial water is therefore essential for securing progress in all these areas. Molecular dynamics simulations were performed to provide molecular level insights of the structural and dynamic behavior of interfacial water near various solid substrates. Density profiles, radial distribution functions, and in-plane density distributions were calculated to study the effect of silica, alumina, and graphite surfaces on the structure of interfacial water. Our results show the formation of two distinct structured water layers with in-plane density distributions highly dependent on the surface chemistry of the substrate. Our findings suggest that due to the surface, the perturbation of the water structure decreases as the distance from the solid substrate increases, becoming a non-factor for distances greater than ~14 Å from the surface. The in-plane organization of water molecules in contact with the surface also locally affects the hydrogen bond network and consequently the dynamic behavior of interfacial water. The dynamic properties were assessed in terms of residence and reorientation correlation functions. An anisotropic dynamic reorientation was observed for water at the silica surface. Towards deploying experimental techniques to validate our predictions, massive molecular dynamics simulations were utilized to study hydration forces near alumina surfaces. A single-walled carbon nanotube (CNT) was employed to mimic an atomic force microscope (AFM) tip used in force spectroscopy. The results illustrate oscillatory hydration forces that act on the CNT at small separations. Changes on the local interfacial water density due to the presence of the CNT tip yield non-sinusoidal oscillations on the force profiles with a width of approximately the size of a water molecule. High local water density yields pronounced repulsive forces, while local density depletion yields attractive forces. Finally, we studied the behavior of aqueous electrolyte solutions in slit-shaped silica nanopores. The results support the existence of ion-specific effects under confinement, which can be explained by the properties of interfacial water
INVESTIGATIONS OF CARTILAGE LUBRICITY AND INTERACTIONS BETWEEN CARBON NANOTUBES AND PHOSPHOLIPID BILAYERS
Full text linkBecause one of the principal functions of articular cartilage in joints is to provide support in diarthrodial joints, transmitting loads with minimum friction and wear, it is likely that understanding the lubrication mechanism in articular cartilage will lead to therapeutic strategies to relieve mild symptomatic osteoarthritis, and possibly to improve the efficacy and expected lifetime of prosthetic implants. For this reason, we used a pin-on-disc tribometer to measure the friction coefficient of both pristine and mechanically damaged cartilage samples in the presence of different lubricant solutions. We find that the experimental set-up allows us to assess different lubrication mechanisms active in cartilage. Among the lubricants considered, 100mg/ml of 100,000 Da polyethylene oxide (PEO) in phosphate buffered saline (PBS) appears to be as effective as synovial fluid (SF), especially on the mechanically-damaged cartilage. It is possible that the viscosity of the lubricant enhances cartilage lubrication via the interstitial fluid pressurization mechanism, maximized by the experimental set up adopted in our friction tests.We also conducted experiments to investigate how single walled carbon nanotubes (SWNTs) interact with phospholipid membranes. The work will both contribute to prevent adverse health effects due to SWNTs, and enable the applicability of SWNTs in advanced scientific areas such as controlled drug delivery, tissue (i.e., cartilage) culture and regeneration, and/or cancer therapy. Our primary results suggest that the presence of liposomes can keep SWNTs dispersed in water at low surfactant concentration. It is likely that individual or slightly bundled SWNTs interact with phospholipid membranes without significant disruption of the structure of phospholipid bilayer
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
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