Guía práctica sobre la gestación subrogada en Estados Unidos

España, tanto como el resto de los países occidentales están viviendo la problemática de la regulación de la gestación como un problema actual, sin embargo, nos enfrentamos ante un hecho, que lleva vivo cuarenta años, pero se ha hecho caso omiso. Los parlamentos europeos acuñan la idea de que es una práctica que va en contra de la dignidad de la mujer, y por esa razón no entrar a analizar la situación real para ofrecer una respuestas a sus ciudadanos que son usuarios de este turismo reproductivo. Al proceder a la regulación de la gestación subrogada entramos en un choque entre el avance de la ciencia en materia reproductiva y la ilegalidad, en el que el legislador se centra únicamente en la determinación de la filiación. Así pues, nos encontramos en un escenario en el que esta práctica se sigue realizando, cada vez más, y nuestro legislador no aporta una solución más allá de la que dio la Dirección General de los Registros y del Notariado en 2010. En virtud de lo mencionado, se ofrece una propuesta de ley, tomando de referencia las discrepancias existentes entre los tribunales y los organismos oficiales del Estado. A su vez, se ofrece una guía práctica relativa a todo el proceso existente para ser padres mediante gestación subrogada en Estados Unidos y posteriormente retornar a España

Development of Cocontinuous Morphologies in Initially Heterogeneous Thermosets Blended with Poly(methyl methacrylate)

Morphology and phase separation process in blends of a network-forming reactive polymer, poly(aminopropylmethylsiloxane) (PAMS), in a poly(methyl methacrylate) (PMMA)-modified epoxy system were studied using optical, epifluorescence and scanning electron microscopy, Fourier transform infrared spectroscopy (FTIR), and dynamic mechanical thermal analysis (DMTA). The thermoset system was bisphenol A diglycidyl ether (DGEBA) with different PMMA percentages, 2−10% w/w. Phase separation and reaction advancement were monitored in situ. At the concentration studied, PMMA does not influence the kinetics of the curing process, but it strongly affects the reactive compatibilization between DGEBA and PAMS. The morphology obtained consists of a continuous thermoplastic-rich phase surrounding thermosetting connected polyhedral particles of 5−15 μm. This cocontinuous morphology is observed independently of the percentage of PMMA. Results show that the morphology is strongly influenced by the diffusion and viscosity conditions during reactive compatibilization and phase separation. An increase in PMMA content leads to a decrease in the thermosetting polyhedral particle size. In contrast, an increase in curing temperature leads to bigger sizes. The addition of thermoplastic polymers to initially nonhomogeneous reactive blends is a potential route for generating cocontinuous morphologies irrespective of the thermoplastic contentThe authors would like to ex-press their gratitude to the Epoxsil (MAT2000-0391-P4-02) and Fibrodont (MAT2001-0677-P3) projects for financial support. The authors would also like to thank to Dr. I. Esteban (UNED) for his assistance with the TOM micrographs and to Dr. J. Iruin (UPV) for his assistance with the density measurements

Detección de microplásticos a través de ICP-MS

En este trabajo se estudia la viabilidad de ICP-MS para la detección de microplásticos.Se me ha indicado cambiar la portada, este trabajo contiene la portada correcta.<br /

Fluorescence probes the early formation of network at the interface of epoxy-silica nanocomposite during curing

The effect of surface modified silica on the cure behavior at the interface of epoxy-silica nanocomposites has been analyzed monitoring the fluorescence of the dansyl probe located at different distances from the silica surface by means of molecular tethers. FTIR analysis revealed the catalytic role of the surface hydroxyls, which is modulated by the surface modification. Fluorescence results show that network formation and associated phenomena as gelation and vitrification occurs first at the interface. The exchange of branched species throughout the permeable interface spreads its influence to the whole system until vitrification is reached.Authors are gratefully acknowledged to Spanish Ministerio de Economía y Competitividad for financial support under grant MAT2010-17091

Confocal microscopy study of phase morphology evolution in epoxy/polysiloxane thermosets

The morphology of stoichiometric initially immiscible reactive blends of DGEBA epoxy resin and poly(3-aminopropylmethylsiloxane) has been characterized by laser scanning confocal microscopy. Observations were done on samples cured isothermally at different curing temperatures in the range 20–120 °C as well as in situ and in real time at 60 °C. Three different processes were revealed: coalescence, which occurs primarily at very low conversion, diffusion of DGEBA through polysiloxane-rich domains and chemical reaction, which occurs at the interphase between both phases. The interphase-thickness and compositional gradients were characterized by laser scanning confocal microscopy (LSCM). Results show that as curing temperature increases within the studied range, the material becomes more homogeneous although the interphase thickness remains almost constant.The authors would like to acknowledge the financial support from projects Epoxsil (MAT2000-0391-P4-02) and Fibrodont (MAT2001-0677-P3)

Interfacial characterization of epoxy/silica nanocomposites measured by fluorescence

Artículo publicado en papel: enero 2015 pero disponible online desde 10 noviembre 2014.Fluorescence labeling was used as a tool for the interfacial characterization of nanocomposites. The solvatochromic probe dansyl chloride was employed as interfacial reporter in epoxy/silica nanocomposites. Molecular spacers (organosiloxanes and polyetheramines) of different lengths were used to vary the location of the chromophore at the interface. The steady state and time resolved fluorescent responses reflect a rigid polar interface. Fluorescence changes during heating at a constant rate were analyzed for determining the local glass transition (Tg) at the interface region. The fluorescence results were then compared to the Tg obtained from differential scanning calorimetry and the results showed the existence of a gradient interface of a few nanometers thick having different properties than the bulk matrix. The thickness of this interface is small but its altered dynamics due to strong interactions with the nanofiller spreads its influence throughout the whole matrix.J.C. Cabanelas, C. Antonelli, J. Baselga and B. Serrano gratefully acknowledge Spanish Ministerio de Educación, Cultura y Deporte (MAT2010-17091) for financial support. R. Ozisik acknowledges support from the United States National Science Foundation under Grant No. 1200270

Recent Advances in MXene/Epoxy Composites: Trends and Prospects

Epoxy resins are thermosets with interesting physicochemical properties for numerous engineering applications, and considerable efforts have been made to improve their performance by adding nanofillers to their formulations. MXenes are one of the most promising functional materials to use as nanofillers. They have attracted great interest due to their high electrical and thermal conductivity, hydrophilicity, high specific surface area and aspect ratio, and chemically active surface, compatible with a wide range of polymers. The use of MXenes as nanofillers in epoxy resins is incipient; nevertheless, the literature indicates a growing interest due to their good chemical compatibility and outstanding properties as composites, which widen the potential applications of epoxy resins. In this review, we report an overview of the recent progress in the development of MXene/epoxy nanocomposites and the contribution of nanofillers to the enhancement of properties. Particularly, their application for protective coatings (i.e., anticorrosive and friction and wear), electromagnetic-interference shielding, and composites is discussed. Finally, a discussion of the challenges in this topic is presented

Mechanism of morphology development in HDGEBA/PAMS hybrid thermosets: Monte Carlo simulation and LSCM study

Reactive combinations of aliphatic epoxy resins and functional polysiloxanes form a class of hybrid thermosetting materials with properties that may come from both the organic and the inorganic phases. The two typically immiscible phases form a suspension whose morphology, composition, and thermal properties vary with curing time. The aim of this research was to elucidate the mechanism by which morphology changed with time and to simulate it through Metropolis-Monte Carlo. The selected system was hydrogenated epoxy (HDGEBA) and a synthetic polyaminosiloxane (PAMS). It was studied by DSC, FTnIR, gel point, viscometry, and in-situ laser scanning confocal microscopy. A mechanism for morphology generation was proposed and simulated, exploring a wide range of values of the "a priori" relevant variables. The essential features were captured by simulations with a reasonable agreement with experimental data. However, the complete process was more complex than the geometrical approach of the simulation. The main deviations that were found and qualitatively explained are: (i) the induction period on the rate of coalescence, and (ii) PAMS-rich domain average size increases faster than predictions.This research was funded by project PID2021-125302NB-I00 financed by the Spanish Ministry of Science and Innovation (MCIN/AEI/10.13039/501100011033) and FEDER Una manera de hacer Europa, and TED2021-131847B-C21 financed by the Spanish Ministry of Science and Innovation (Refs: MCIN/AEI/10.13039/501100011033) and Union Europea NextGenationEU/PRT

Water absorption in polyaminosiloxane-epoxy thermosetting polymers

Water absorption is a common problem in epoxy-based composites, especially in interfacial regions. In contrast to epoxy resins, silicones are hydrophobic materials. Modification of epoxy thermosets with silicones should improve physical properties because of decrease in water diffusion. Bisphenol-A diglycidyl ether (DGEBA) was cured with a synthesised aminopropyl perfunctionalised siloxane. Water absorption was analysed by different techniques, including near infrared (FTIR) water absorbance at 5200 cm−1 and gravimetry. Fick’s law diffusion coefficients were calculated. Swelling equilibrium of the resin was also analysed. Absorbed water catalyses the curing reaction strongly, allowing to reach high conversions