Showing papers by "Rafael Gavara published in 2017"
TL;DR: In this paper, a matrix encapsulation of curcumin in gelatin through electrohydrodynamic atomization (EHDA) was proposed to overcome the problem of its insolubility in water.
107 citations
TL;DR: In this article, thin zein films with 10% Zataria multiflora Boiss essential oil (ZEO) were successfully applied as a coating on PP bags, and the effectiveness of the active bags was tested in a more complex medium than liquid bacterial growth media, that is cow's milk inoculated with the above microorganisms.
91 citations
TL;DR: Ethylene-vinyl alcohol copolymer films incorporating EO from Origanum vulgare, Cinnamomum zeylanicum or their major active constituents, carvacrol (CAR) and cinnamaldehyde (CINHO), respectively, were developed and assayed to control growth of Aspergillus flavus and A. parasiticus and AF production in maize grains under different aw and temperature regimens.
31 citations
TL;DR: In this article, a model based on both Michaelis-Menten and chemical kinetics equations was developed and assessed in order to describe the respiration and ethylene generation of avocado (Persea americana cv. Hass) and feijoa fruits (Acca sellowiana Berg).
Abstract: A proper description of the respiration and ethylene generation is important in the development of package systems for the preservation of fresh fruits and vegetables. In this work, a model based on both Michaelis-Menten and chemical kinetics equations was developed and assessed in order to describe the respiration and ethylene generation of avocado (Persea americana cv. Hass) and feijoa fruits (Acca sellowiana Berg) from experimental data obtained at different temperatures by a closed system method. The temperature effect in both processes was described using Arrhenius-type relationships. After this, avocadoes and feijoas were packed in perforated low-density polyethylene (LDPE) and polypropylene (PP) bags for 8 days at 12°C and 80% RH to validate the usefulness of the model to describe the gas evolution in modified atmosphere packaging (MAP). For avocado fruits, respiration rates of 2680-3030 cm3 kg-1 d-1 were obtained at 24 °C and normal atmosphere, and 3650-4230 cm3 kg-1 d-1 for feijoa fruits....
22 citations
TL;DR: The results showed that oxygen permeability and transmissibility requirements of the lens have been addressed through the use of siloxane containing hydrogels, and ionic lenses presented values of ionic permeable and diffusivity higher than most non-ionic lenses.
Abstract: Oxygen permeability, diffusion coefficient of the sodium ions and water flux and permeability in different conventional hydrogel (Hy) and silicone-hydrogel (Si-Hy) contact lenses have been measured experimentally. The results showed that oxygen permeability and transmissibility requirements of the lens have been addressed through the use of siloxane containing hydrogels. In general, oxygen and sodium chloride permeability values increased with the water content of the lens but there was a percolation phenomenon from a given value of water uptake mainly in the Si-Hy lenses which appeared to be related with the differences between free water and bound water contents. The increase of ion permeability with water content did not follow a unique trend indicating a possible dependence of the chemical structure of the polymer and character ionic and non-ionic of the lens. Indeed, the salt permeability values for silicone hydrogel contact lenses were one order of magnitude below those of conventional hydrogel contact lenses, which can be explained by a diffusion of sodium ions occurring only through the hydrophilic channels. The increase of the ionic permeability in Si-Hy materials may be due to the confinement of ions in nanoscale water channels involving possible decreased degrees of freedom for diffusion of both water and ions. In general, ionic lenses presented values of ionic permeability and diffusivity higher than most non-ionic lenses. The tortuosity of the ionic lenses is lower than the non-ionic Si-Hy lenses. Frequency 55 and PureVision exhibited the highest water permeability and flux values and, these parameters were greater for ionic Si-Hy lenses than for ionic conventional hydrogel lenses. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 105B: 2218-2231, 2017.
14 citations
TL;DR: It is shown that Au clusters can be prepared with ethylene-vinyl alcohol copolymers, charcoal, and different metal oxides in >15% yields, as unambiguously determined using a very simple and extremely sensitive analytical reaction test.
11 citations
TL;DR: In this article, it is shown that the independent dosage of Au clusters and metallic Au nanoparticles dramatically improves the catalytic activity of Au for the Sonogashira reaction, enabling the coupling of a wide range of iodo-, bromo- and activated chloro-derivatives with aromatic and aliphatic alkynes, and outperforming ligand-free Pd and Cu catalysts.
Abstract: Metal nanocrystallites present saturated atoms, in planes, and unsaturated metal atoms, in corners and vertices, for catalytic applications. However, both sites are spatially complementary and simultaneously excluding for a given particle, thus their number cannot be independently maximized for a catalytic process. Here, it is shown that the independent dosage of Au clusters and metallic Au nanoparticles dramatically improves the catalytic activity of Au for the Sonogashira reaction, enabling the coupling of a wide range of iodo‐, bromo‐, and activated chloro‐derivatives with aromatic and aliphatic alkynes, and outperforming ligand‐free Pd and Cu catalysts. Mechanistic studies reveal that the unsaturated atoms of the cluster activate the alkyne and that the saturated atoms of the metallic nanoparticle preferentially activate the halide, to finally perform the coupling. Thus, a precise combination of sub‐nanometric metal clusters and metal nanoparticles, together, constitute a new catalytic strategy to substitute metal nanocrystallites in reactions in which both unsaturated and saturated atoms play a key role.
9 citations
TL;DR: Overall, this study shows myogenic differentiation in normal growth media for several cell types under SW conditions, avoiding the use of growth factors and cytokines, i.e., solely by culturing cells within the SW environment.
Abstract: Sandwichlike (SW) cultures are engineered as a multilayer technology to simultaneously stimulate dorsal and ventral cell receptors, seeking to mimic cell adhesion in three-dimensional (3D) environments in a reductionist manner. The effect of this environment on cell differentiation was investigated for several cell types cultured in standard growth media, which promotes proliferation on two-dimensional (2D) surfaces and avoids any preferential differentiation. First, murine C2C12 myoblasts showed specific myogenic differentiation. Human mesenchymal stem cells (hMSCs) of adipose and bone marrow origin, which can differentiate toward a wider variety of lineages, showed again myodifferentiation. Overall, this study shows myogenic differentiation in normal growth media for several cell types under SW conditions, avoiding the use of growth factors and cytokines, i.e., solely by culturing cells within the SW environment. Mechanistically, it provides further insights into the balance between integrin adhesion to...
4 citations