Memoria 1987

La memoria que presentamos trata de significar, con criterios lo más objetivos posible, los hechos más destacados de la actividad científica y técnica del CSIC a lo largo del año 1987 El hecho más destacado del año es sin duda la aprobación del Programa Sectorial del CSIC por la Junta de Gobierno, en su reunión del día 8 de Mayo. Este Programa enlaza con las anteriores programaciones trianuales que han enmarcado la actividad del Organismo durante 1982-1984 y 1985-1987, y su objetivo es contribuir, mediante la investigación científica y el desarrollo tecnológico, a la consecución de los objetivos de interés general que establece el artículo 2 de la Ley de la Ciencia. También merece señalarse la creación de la Oficina de Relaciones con la Comunidad Económica Europea, adscrita al Gabinete de Estudios de la Presidencia, que obedece a la necesidad de canalizar la participación del CSIC en el Programa Marco 1 y D de la Comunidad Europea. En el mes de Diciembre se fallaron los Premios de Periodismo Científico, en su segunda edición; galardones que fueron creados el año anterior para reconocer la labor de los profesionales de la información, —personas y empresas periodísticas—, que han realizado una tarea relevante en el campo de la divulgación científica y técnica en los medios de comunicación españoles. Por último, cabe reseñar que toda la documentación recogida en esta publicación se ha dividido en dos partes bien diferenciadas. En la primera, que tiene un carácter más conceptual, se exponen datos globales relativos a la información general del organismo, en tanto que la segunda parte —con datos más individualizados—, se dedica exclusivamente a la información o actividad científica acontecida en los distintos Centros o Institutos.N

Graphene coating of Nafion(R)^{(R)} membranes for enhanced fuel cell performance

Electrochemically exfoliated graphene (e-G) thin films on Nafion$^{(R)}$ membranes exhibit a selective barrier effect against undesirable fuel crossover. The approach combines the high proton conductivity of state-of-the-art Nafion$^{(R)}$ and the ability of e-G layers to effectively block the transport of methanol and hydrogen. Nafion$^{(R)}$ membranes are coated with aqueous dispersions of e-G on the anode side, making use of a facile and scalable spray process. Scanning transmission electron microscopy (STEM) and electron energy-loss spectroscopy (EELS) confirm the formation of a dense percolated graphene flake network which acts as diffusion barrier. The maximum power density in direct methanol fuel cell (DMFC) operation with e-G coated Nafion$^{(R)}$ N115 is 3.9 times higher than the Nafion$^{(R)}$ N115 reference (39 vs. 10 mW cm$^{-2}$ @ 0.3 V) at 5M methanol feed concentration. This suggests the application of e-G coated Nafion$^{(R)}$ membranes for portable DMFCs, where the use of highly concentrated methanol is desirable

Towards the Development of THz-Sensors for the Detection of African Trypanosomes

AbstractHuman African trypanosomiasis (HAT) is a neglected tropical disease (NTD) for which adequate therapeutic and diagnostic measures are still lacking. Causative agent of HAT is the African trypanosome, a single-cell parasite, which propagates in the blood and cerebrospinal fluid of infected patients. Although different testing methods for the pathogen exist, none is robust, reliable and cost-efficient enough to support large-scale screening and control programs. Here we propose the design of a new sensor-type for the detection of infective-stage trypanosomes. The sensor exploits the highly selective binding capacity of nucleic acid aptamers to the surface of the parasite in combination with passive sensor structures to allow an electromagnetic remote read-out using terahertz (THz)-radiation. The short wavelength provides a superior interaction with the parasite cells than longer wavelengths, which is essential for a high sensitivity. We present two different sensor structures using both, micro- and nano-scale elements, as well as different measurement principles.</jats:p

Effect of Particle Size on the Orientation and Order of Assemblies of Functionalized Microscale Cubes Formed at the Water/Air Interface

The impact of the particle size and wettability on the orientation and order of assemblies obtained by self-organization of functionalized microscale polystyrene cubes at the water/air interface is reported. An increase in the hydrophobicity of 10- and 5-μm-sized self-assembled monolayer-functionalized polystyrene cubes, as assessed by independent water contact angle measurements, led to a change of the preferred orientation of the assembled cubes at the water/air interface from face-up to edge-up and further to vertex-up, irrespective of microcube size. This tendency is consistent with our previous studies with 30-μm-sized cubes. However, the transitions among these orientations and the capillary force-induced structures, which change from flat plate to tilted linear and further to close-packed hexagonal arrangements, were observed to shift to larger contact angles for smaller cube size. Likewise, the order of the formed aggregates decreased significantly with decreasing cube size, which is tentatively attributed to the small ratio of inertial force to capillary force for smaller cubes in disordered aggregates, which results in more difficulties to reorient in the stirring process. Experiments with small fractions of larger cubes added to the water/air interface increased the order of smaller homo-aggregates to values similar to neat 30 μm cube assemblies. Hence, collisions of larger cubes or aggregates are shown to play a decisive role in breaking metastable structures to approach a global energy minimum assembly