Ionic behavior assessment of surface-active compounds from corn steep liquor by exchange resins

Depending on their ionic nature, biosurfactants can be classified as nonionic, anionic, cationic, or amphoteric. The ionic behavior of biosurfactants is an important characteristic that dictates their use in industrial applications. In this work, a biosurfactant extract obtained from corn steep liquor was subjected to anionic or cationic resins, in order to study the ionic behavior under different operational conditions using response surface methodology. The independent variables included in the study are the dilution of biosurfactant solution, the amount of cationic or anionic resin, and the extraction time, whereas the dependent variables studied consisted of the surface tension of biosurfactant aqueous solution, after contacting with anionic or cationic resin. The results showed that biosurfactant extracted from corn steep liquor is amphoteric, since both resins were able to entrap this biosurfactant, making it particularly suited for use in personal care preparations for sensitive skin.Peer ReviewedPostprint (author's final draft

Procedimiento para la purificación de Triglicéridos que contienen ácido Gamma-Linolenico en posición SN-2

Número de publicación: ES2345529 A1 (24.09.2010) También publicado como: ES2345529 B2 (21.07.2011) Número de Solicitud: Consulta de Expedientes OEPM (C.E.O.) P200900892(13.03.2009)Procedimiento para la purificación de triglicéridos que contienen ácido gamma-linolénico en posición sn-2. Con la finalidad de purificar triglicéridos que contienen ácido gamma-linolénico a partir de fuentes naturales, se utiliza una columna cromatográfica gravimétrica en fase normal, trabajando en gradiente de polaridad con solventes biocompatibles. Así se consigue la purificación de triglicéridos que cuentan en su estructura con una o más moléculas de ácido gamma-linolénico, pudiendo ser utilizados con diversos fines. Con esta metodología es posible trabajar a escala industrial, pues es fácilmente escalable, a diferencia de otras técnicas que son aplicables a escala analítica pero presentan serios inconvenientes en cuanto a coste y adiestramiento del personal a la hora de utilizarlas con fines industriales, como por ejemplo la cromatografía líquida de alta resolución (HPLC).Universidad de Almerí

Three eras of micellization

Micellization is the precipitation of lipids from aqueous solution into aggregates with a broad distribution of aggregation number. Three eras of micellization are characterized in a simple kinetic model of Becker-Döring type. The model asigns the same constant energy to the (k-1) monomer-monomer bonds in a linear chain of k particles. The number of monomers decreases sharply and many clusters of small size are produced during the first era. During the second era, nuclei are increasing steadily in size until their distribution becomes a self-similar solution of the diffusion equation. Lastly, when the average size of the nuclei becomes comparable to its equilibrium value, a simple mean-field Fokker-Planck equation describes the final era until the equilibrium distribution is reached

Innovating the Teach-In to Transform the Faculty: Findings from a #BlackLivesMatter Teach-In

College students across the U.S. have been mobilizing their campuses in exposing institutional racism, biases, and curriculum structures that have historically marginalized students of color. As a response to ongoing racial justice movements such as #BlackLivesMatter, we developed a new teach-in model with the aim of creating a transformative experience for faculty and students. Our teach-in challenged faculty to incorporate topics related to #BlackLivesMatter to the discipline-specific content of their course during the same one-week period; this was followed by a campus-wide town hall event. Framed by critical race theory with the goal of creating transformative learning for faculty, we sought to assess the impact of the teach-in from the perspective of teachers. Our findings indicated that our teach-in successfully created an opportunity for faculty to interrogate their curriculum, engage students in race discussions, and develop the knowledge and professional skills needed to tackle a more inclusive social justice curriculum

Novel charged black hole solutions of Born-Infeld type: General properties, Smarr formula and Quasinormal frequencies

We investigate two novel models of charged black holes in the framework of non-linear electrodynamics of Born-Infeld type. In particular, starting from two concrete Lagrangian densities, the corresponding metric potentials, the electric field, the Smarr formula and finally, the (scalar) quasinormal modes are computed for each model. Our findings show that although the models look very similar, their quasinormal spectra are characterized by certain differences.Comment: 18 pages, 7 figures, 3 tables, to be published in Annals of Physic

The unit cell parameters and electrical conduction of some new solar cell materials

New materials are being investigated that could yield solar energy conversion efficiency comparable in device production cost to the standard electric power generators. Continuing with this effort, in recent years solar cells with efficiency close to 20 %, prepared with alloys of CuIn1-xGaxSe2 has been reported. It is shown that the normalized values of the unit cell parameters a and c of the ordered defect compounds with respect to their corresponding 1:1:2 phase, that are formed on the In(Ga)-rich side of the pseudo-binary phase diagram of [Cu2(Se,Te)]X–[(In2,Ga2)(Se3,Te3)]1-X, vary linearly with the effective cation radius reff for the tellurides and selenides of Cu-In and Cu-Ga systems. This universal relationship has important significance. The unit cell dimensions of other chalcopyriterelated ordered defect compounds of these systems that have not been synthesized so far can be estimated. Because of the presence of shallow donor and acceptor levels due to the presence of cation-cation disorders in Cu(In,Ga)Se2 and ordered defects in Cu(In,Ga)3(Se,Te)5, the impurity band in these compounds starts to form between liquid helium and nitrogen temperatures. This permits to study the variable range hopping (VRH) conduction in the impurity band over a much wider temperature range

Texture changes during chilled storage of wild and farmed blacspot seabream (Pagellus bogaraveo) fed different diets

The impact of changes in dietary lipids and protein sources on texture was evaluated on farmed blackspot seabream (Pagellus bogaraveo) throughout 14 days of ice storage and compared with wild fish. A commercial diet formulated with a high proportion of lipids, and two diets formulated with an important reduction of lipid levels by 60% and adding either plant protein sources (LL diet) or fishmeal (LL + diet) were supplied during growth until commercial size was attained. In the wild fish, the raw fillet hardness was significantly higher than in farmed fish during the entire ice-storage period. In the farmed fish, an increase of muscle lipid accumulation and change of fiber density were responsible for the variations in texture in the raw fillet. The highest reduction was found in fish fed with diets LL+ and LL. The texture parameters studied on the cooked fillets showed no significant differences, neither attributable to the diets nor to the ice-storage period.JUNTA ASESORA DE CULTIVOS MARINOS (JACUMAR)Postprin

Photosensitivity Color-Center Model for Ge-Doped Silica Preforms

A new photosensitivity physical model for Ge-doped silica preforms based on color-center photoreactions is presented. Simulation results are in close agreement with experimental results obtained by several condensed matter physics research groups working in this field, suggesting that the photoreactions of this model may, indeed, describe the physical processes involved in Ge-doped silica preform photosensitivity. The proposed photosensitivity model is defined by two differential equations that describe the temporal evolution of a set of color-center concentrations. The first is a modification of a very fast reversible reaction previously proposed by Fujimaki et al., where the reaction precursor has a different chemical structure (it is a neutral oxygen divacancy NODV unrelated to the previously proposed germanium lone pair center GLPC). The chemical structure of this precursor defect explains the generation of nonintrinsic neutral oxygen monovacancy ðNOMVÞ color centers. These centers are transformed into GeE0 defects by means of a second nonlinear reaction. This justifies the slow increase in the absorption peak experimentally measured at 6.3 eV, which had no satisfactory explanation.Ministerio de Ciencia y Tecnología TIC2001-2969-C03-0