1,720,965 research outputs found
Solubility of 1,5 - napthalene diamine and 1,8 - octane diamine in supercritical carbon dioxide: experimental determination and correlation.
No full textSolubility of 4,4 - diamino diphenyl methane in supercritical carbon dioxide: Experimental determination and correlation.
No full textSolubility of diamines in supercritical carbon dioxide: Experimental determination and correlation.
No full textAntisolvent Coprecipitation of Biopolymers and Drugs
No full textControlled – delivery products are finding considerable attention, because of their drug’s therapeutic effect prolongation, that keeps the drug concentration in the body between a lower limit (therapeutic limit) and an upper limit (toxicity limit). These devices are traditionally obtained by encapsulation of a drug in a polymer matrix using an organic solvent with the following steps:
• Solubilization of the active principle in an organic solvent;
• Partitioning of the active principle between the solvent and the polymer matrix;
• Residual solvent removal.
Problems arise for the elimination of residual solvent to acceptable limits. Antisolvent precipitation can be an alternative method for the encapsulation of a drug in a polymer matrix. In this study the feasibility of the technique, known as Supercritical Anti Solvent recrystallization (SAS), will be investigated in order to obtain the co-precipitation of a drug and a biodegradable polymer from an appropriate organic solvent. A biodegradable polymer, poly(L-lactide) (L-PLA) is considered, with a non steroidal anti-inflammatory drug (NSAID), nimesulide, as active principle
Activity Coefficients at Infinite Dilution by GLC in Alkanediamines as Stationary Phases
No full textThe infinite-dilution activity coefficients (γ∞) of paraffins, olefins, chloroparaffins, aromatics, alcohols, ethers, and acetates were measured by medium-pressure gasliquid chromatography (GLC) in alkanediamines: octane-1,8-diamine, decane-1,10-diamine, and dodecane-1,12-diamine at temperatures from (328.15 to 363.15) K. The present measurements show good agreement with available literature data. The partial molar excess enthalpies at infinite dilution were calculated from the experimental γi∞ values obtained over the temperature range. In order to determine the different interactions between the solutes and solvents, the linear solvation energy relationship (LSER) or “Abraham method” was applied
Development of highly performant hybrid materials based on phthalonitrile resin for a simultaneous ballistic and nuclear shielding protection
No full textIn this study, a new high-performance hybrid material was designed targeting an efficient ballistic and nuclear shielding protection. To achieve this goal, a typical highly performant thermosetting resin, namely the phthalonitrile (PN) resin, was reinforced with Kevlar fibers (KF-29), as continuous phase, and erbium oxide (Er2O3) nanoparticles, as discontinuous phase. The reinforcing phases underwent a silane surface modification to create a fully connected network aiming an improved stress transfer between the constituents. The mechanical investigations through tensile and bending testing confirmed the positive effect of the addition of an increasing amount (up to 20 wt%) of the Er2O3 nanoparticles. The hybrids also provided excellent gamma rays shielding performances with a screening ratio of about 33% for a 3 cm thick sample. In the meantime, the ballistic tests evaluated under the National Institute of Justice standard (NIJ standard-0101.06-IIA) also highlighted an improved kinetic energy absorption following the increase in the amounts of the discontinuous phase. Overall, this study unraveled for the first time ever the benefits obtained from a fully connected hybrid network in the field of ballistic and radiation protection
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
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