Eliminació autotròfica de nitrogen en una pila biològica (microbial fuel cells )

L’aigua i l’energia formen un binomi indissociable. En relació al cicle de l’aigua, des de fa varies dècades s’han desenvolupat diferents formes per recuperar part de l’energia relacionada amb l’aigua, per exemple a partir de centrals hidroelèctriques. No obstant, l’ús d’aquesta aigua també porta associat un gran consum energètic, relacionat sobretot amb el transport, la distribució, la depuració, etc... La depuració d’aigües residuals porta associada una elevada demanda energètica (Obis et al.,2009). En termes energètics, tot i que la despesa elèctrica d’una EDAR varia en funció de diferents paràmetres com la configuració i la capacitat de la planta, la càrrega a tractar, etc... es podria considerar que el rati mig seria d’ aproximadament 0.5 KWh•m-3.Els principals costos d’explotació estan relacionats tant amb la gestió de fangs (28%) com amb el consum elèctric (25%) (50% tractament biològic). Tot i que moltes investigacions relacionades amb el tractament d’aigua residual estan encaminades en disminuir els costos d’operació, des de fa poques dècades s’està investigant la viabilitat de que l’aigua residual fins i tot sigui una font d’energia, canviant la perspectiva, i començant a veure l’aigua residual no com a una problemàtica sinó com a un recurs. Concretament s’estima que l’aigua domèstica conté 9.3 vegades més energia que la necessària per el seu tractament mitjançant processos aerobis (Shizas et al., 2004). Un dels processos més desenvolupats relacionats amb el tractament d’aigües residuals i la producció energètica és la digestió anaeròbia. No obstant, aquesta tecnologia permet el tractament d’altes càrregues de matèria orgànica generant un efluent ric en nitrogen que s’haurà de tractar amb altres tecnologies. Per altre banda, recentment s’està investigant una nova tecnologia relacionada amb el tractament d’aigües residuals i la producció energètica: les piles biològiques (microbial fuel cells, MFC). Aquesta tecnologia permet obtenir directament energia elèctrica a partir de la degradació de substrats biodegradables (Rabaey et al., 2005). Les piles biològiques, més conegudes com a Microbial Fuel Cells (acrònim en anglès, MFC), són una emergent tecnologia que està centrant moltes mirades en el camp de l’ investigació, i que es basa en la producció d’energia elèctrica a partir de substrats biodegradables presents en l’aigua residual (Logan., 2008). Els fonaments de les piles biològiques és molt semblant al funcionament d’una pila Daniell, en la qual es separa en dos compartiments la reacció d’oxidació (compartiment anòdic) i la de reducció (compartiment catòdic) amb l’objectiu de generar un determinat corrent elèctric. En aquest estudi, bàsicament es mostra la posada en marxa d'una pila biològica per a l'eliminació de matèria orgànica i nitrogen de les aigües residuals.

Mieloma múltiple: rendimiento del estudio del cariotipo por técnicas convencionales y de hibridación in situ fluorescente. Significado pronóstico de las ganacias de 1 q.

En éste estudio analizamos el rendimiento de las técnicas citogenéticas utilizadas en los protocolos diagnósticos del MM (CC y técnicas de FISH). En primer lugar caracterizamos la serie de pacientes y los estratificamos en grupos de riesgo según los sistemas de estadificación actuales. Después estudiamos el porcentaje de cariotipos patológicos con cada una de las técnicas y en conjunto, encontrando un 40% de cariotipos patológicos por CC y de estos un 11,5% pertenecían a estudios con recuentos de CP ≤20% por citomorfología. La técnica de FISH aumentó hasta un 68% los cariotipos patológicos. También hemos realizado la caracterización de los pacientes con ganancias de 1q y su impacto en la evolución de la enfermedad.

QuesTInSitu: from tests to routes for assessment in situ activities

Test-based assessment tools are mostly focused on the use of computers. However, advanced Information and Communication Technologies, such as handheld devices, opens up the possibilities of creating new assessment scenarios, increasing the teachers’ choices to design more appropriate tests for their subject areas. In this paper we use the term Computing-Based Testing (CBT) instead of Computer-Based Testing, as it captures better the emerging trends. Within the CBT context, the paper is centred on proposing an approach for “Assessment in situ” activities, where questions have to be answered in front of a real space/location (situ). In particular, we present the QuesTInSitu software implementation that includes both an editor and a player based on the IMS Question and Test Interoperability specification and GoogleMaps. With QuesTInSitu teachers can create geolocated questions and tests (routes), and students can answer the tests using mobile devices with GPS when following a route. Three illustrating scenarios and the results from the implementation of one of them in a real educational situation show that QuesTInSitu enables the creation of innovative, enriched and context-aware assessment activities. The results also indicate that the use of mobile devices and location-based systems in assessment activities facilitates students to put explorative and spatial skills into practice and fosters their motivation, reflection and personal observation.

Particle agglomeration study in rf silane plasmas: In situ study by polarization-sensitive laser light scattering

To determine self‐consistently the time evolution of particle size and their number density in situ multi‐angle polarization‐sensitive laser light scattering was used. Cross‐polarization intensities (incident and scattered light intensities with opposite polarization) measured at 135° and ex situ transmission electronic microscopy analysis demonstrate the existence of nonspherical agglomerates during the early phase of agglomeration. Later in the particle time development both techniques reveal spherical particles again. The presence of strong cross‐polarization intensities is accompanied by low‐frequency instabilities detected on the scattered light intensities and plasma emission. It is found that the particle radius and particle number density during the agglomeration phase can be well described by the Brownian free molecule coagulation model. Application of this neutral particle coagulation model is justified by calculation of the particle charge whereby it is shown that particles of a few tens of nanometer can be considered as neutral under our experimental conditions. The measured particle dispersion can be well described by a Brownian free molecule coagulation model including a log‐normal particle size distribution.

In situ fast ellipsometric analysis of repetitive surface phenomena

We present an ellipsometric technique and ellipsometric analysis of repetitive phenomena, based on the experimental arrangement of conventional phase modulated ellipsometers (PME) c onceived to study fast surface phenomena in repetitive processes such as periodic and triggered experiments. Phase modulated ellipsometry is a highly sensitive surface characterization technique that is widely used in the real-time study of several processes such as thin film deposition and etching. However, fast transient phenomena cannot be analyzed with this technique because precision requirements limit the data acquisition rate to about 25 Hz. The presented new ellipsometric method allows the study of fast transient phenomena in repetitive processes with a time resolution that is mainly limited by the data acquisition system. As an example, we apply this new method to the study of surface changes during plasma enhanced chemical vapor deposition of amorphous silicon in a modulated radio frequency discharge of SiH4. This study has revealed the evolution of the optical parameters of the film on the millisecond scale during the plasma on and off periods. The presented ellipsometric method extends the capabilities of PME arrangements and permits the analysis of fast surface phenomena that conventional PME cannot achieve.

A general approach to the in situ energy butget of Eudendrium racemosum (Cnidaria, Hydrozoa) in the Western Mediterranean

An in situ energy budget of the hydropolyp Eudendrium racemosum (Cavolini, 1785) is presented. Ingestion and respiration rates and ammonium excretion were studied over two 24 h cycles, with two-hour sample intervals. The species ingested as much as 25.9% of its own biomass per day (minimum rate). Respiration was 1.62 ml O2 g-1 d w h-1 while excretion was 13.6 mM NH4 g-1dw h-1. We estimated that the species increased its biomass at a rate of 9.6% per day (Growth + Reproduction). This value is higher than those previously reported for other cnidarians. We can assume that the capacity of E. racemosum to survive - albeit for a limited period of the year - in the highly-competitive shallow-water communities is based on its high growth rate.

Sedimen-water nutrient fluxes: Preliminary results of in situ measurements in Alfaques Bay, Ebro River Delta.

Sediment-water exchanges of oxygen, ammonium, nitrate, total dissolved nitrogen, phosphate and total dissolved phosphorus were measured by means of an in situ incubator of 7 1 volume and 700 cm2 base area. The incubations lasted for three hours and were done over a whole season on different kinds of sediments in Alfaques Bay. We present some preliminary results on: i) methodological aspects, ii) spatial and temporal variability of fluxes, and iii) estimates of contribution of benthic nutrient regeneration relative to total nutrient loading of the Bay. Oxygen uptake averaged 1700 mmo1 m-2 h-1 (range 200-3500); no differences were found between sandy and muddy sediments. The release of ammonia from the sediment averaged 70 mmo1 m-2 h-1 and was higher in muddy sediments than in sandy ones. Very low to null nitrate and nitrite fluxes and only small fluxes of organic nitrogen were detected. We conclude that ammonium release from sediment is the major path of nitrogen regeneration. Some sediments removed dissolved reactive phosphorus (DRP) from the water and released dissolved organic phosphorus (DOP). Additional manipulative experiments revealed DRP release under particular conditions (turbulence, anoxia). From these data, we estimate that at least 50% of the nitrogen requirements of phytoplankton in the area may be supplied by benthic remineralization.

Consells d’extracció i conservació del material arqueològic in situ

Aquest petit treball pretén esdevenir una guia bàsica per aquells arqueòlegs que desconeixen l’aspecte conservatiu dels materials arqueològics. Així, en primer lloc analitzarem, a grans trets, la composició físicoquímica dels diferents objectes que podem trobar en una excavació i quins són els agents que més els malmeten. Després tractarem d’introduir alguns consells pràctics pel treball de camp.

Optical analysis of textured plastic substrates to be used in thin silicon solar cells

Light confinement strategies in thin-film silicon solar cells play a crucial role in the performance of the devices. In this work, the possible use of Ag-coated stamped polymers as reflectors to be used in n-i-p solar cells is studied. Different random roughnesses (nanometer and micrometer size) have been transferred on poly(methylmethacrylate) (PMMA) by hot embossing. Morphological and optical analyses of masters, stamped polymers and reflectors have been carried out evidencing a positive surface transference on the polymer and the viability of a further application in solar cells.

In situ spectroellipsometric study of the nucleation and growth of amorphous silicon

A detailed in situ spectroellipsometric analysis of the nucleation and growth of hydrogenated amorphous silicon (a:Si:H) is presented. Photoelectronic quality a‐Si:H films are deposited by plasma‐enhanced chemical vapor deposition on smooth metal (NiCr alloy) and crystalline silicon (c‐Si) substrates. The deposition of a‐Si:H is analyzed from the first monolayer up to a final thickness of 1.2 μm. In order to perform an improved analysis, real time ellipsometric trajectories are recorded, using fixed preparation conditions, at various photon energies ranging from 2.2 to 3.6 eV. The advantage of using such a spectroscopic experimental procedure is underlined. New insights into the nucleation and growth mechanisms of a‐Si:H are obtained. The nucleation mechanism on metal and c‐Si substrates is very accurately described assuming a columnar microstructural development during the early stage of the growth. Then, as a consequence of the incomplete coalescence of the initial nuclei, a surface roughness at the 10-15 Å scale is identified during the further growth of a‐Si:H on both substrates. The bulk a‐Si:H grows homogeneously beneath the surface roughness. Finally, an increase of the surface roughness is evidenced during the long term growth of a‐Si:H. However, the nature of the substrate influenced the film growth. In particular, the film thickness involved in the nucleation‐coalescence phase is found lower in the case of c‐Si (67±8 Å) as compared to NiCr (118±22 Å). Likewise films deposited on c‐Si present a smaller surface roughness even if thick samples are considered (>1 μm). More generally, the present study illustrates the capability of in situ spectroellipsometry to precisely analyze fundamental processes in thin‐film growth, but also to monitor the preparation of complex structures on a few monolayers scale.

Estudio biologico de Pterocladia capillacea (Gmelin) Bornet in Bornet & Thuret. Crecimiento de la planta in situ.

Se ha realizado un estudio biológico de Pterocladia capillacea (Gmelin) Bornet in Bornet y Thuret en Estartit y Rosas (noreste de la Península Ibérica), en el cual se ha cuantificado el crecimiento del talo mediante muéstreos mensuales de una población de individuos a los que previamente habíamos cortado la porción ortótropa de su talo en distintas épocas del año. El crecimiento observado es mínimo en invierno y máximo en primavera y principios de otoño. Los resultados obtenidos permiten afirmar que el crecimiento mensual de P. capillacea parece depender fundamentalmente de la época del año, y, en menor grado, del estado de desarrollo de la planta.

AMP-activated protein kinase plays an important evolutionary conserved role in the regulation of glucose metabolism in fish skeletal muscle cells

AMPK, a master metabolic switch, mediates the observed increase of glucose uptake in locomotory muscle of mammals during exercise. AMPK is activated by changes in the intracellular AMP:ATP ratio when ATP consumption is stimulated by contractile activity but also by AICAR and metformin, compounds that increase glucose transport in mammalian muscle cells. However, the possible role of AMPK in the regulation of glucose metabolism in skeletal muscle has not been investigated in other vertebrates, including fish. In this study, we investigated the effects of AMPK activators on glucose uptake, AMPK activity, cell surface levels of trout GLUT4 and expression of GLUT1 and GLUT4 as well as the expression of enzymes regulating glucose disposal and PGC1α in trout myotubes derived from a primary muscle cell culture. We show that AICAR and metformin significantly stimulated glucose uptake (1.6 and 1.3 fold, respectively) and that Compound C completely abrogated the stimulatory effects of the AMPK activators on glucose uptake. The combination of insulin and AMPK activators did not result in additive nor synergistic effects on glucose uptake. Moreover, exposure of trout myotubes to AICAR and metformin resulted in an increase in AMPK activity (3.8 and 3 fold, respectively). We also provide evidence suggesting that stimulation of glucose uptake by AMPK activators in trout myotubes may take place, at least in part, by increasing the cell surface and mRNA levels of trout GLUT4. Finally, AICAR increased the mRNA levels of genes involved in glucose disposal (hexokinase, 6-phosphofructokinase, pyruvate kinase and citrate synthase) and mitochondrial biogenesis (PGC-1α) and did not affect glycogen content or glycogen synthase mRNA levels in trout myotubes. Therefore, we provide evidence, for the first time in non-mammalian vertebrates, suggesting a potentially important role of AMPK in stimulating glucose uptake and utilization in the skeletal muscle of fish.

Estudi sobre l'eficàcia dels mètodes de reescalfament in situ en el tractament de la hipotèrmia accidental en muntanya

En la última dècada, els esports de muntanya, en qualsevol de les seves modalitats, s’han vist incrementats en nombre de practicants. Aquest fet ha comportat un important augment d’incidència de la hipotèrmia accidental. La hipotèrmia accidental és defineix com un estat patològic caracteritzat per la disminució de la temperatura corporal central per sota dels 35ºC, com a resultat de la incapacitat de l’organisme per generar el calor necessari per garantir el manteniment de les funcions fisiològiques. A través d’aquest estudi es vol demostrar que l’actuació in situ, a través de certes mesures de reescalfament, de la víctima que pateix hipotèrmia, milloren la supervivència i les complicacions secundàries d’aquesta patologia, a més a més d’avaluar l’eficàcia d’aquestes tècniques. És a dir, volem demostrar l’efectivitat de l’aplicació terapèutica extrahospitalaria de les tècniques de reescalfament. Realitzarem un estudi quantitatiu observacional analític de caràcter prospectiu a la zona dels Alps francesos d’una mostra de 237 casos d’hipotèrmia en persones practicants d’esports de muntanya que reuneixin uns criteris d’inclusió i exclusió. Els professionals de rescat aplicaran les mesures de reescalfament prèviament pautades, per les quals hauran estat formats, i enregistraran en el full de recollida de dades tota la informació sobre les variables d’estudi. És un estudi on la intervenció principal es porta a terma al medi natural i que per tant les condicions climatològiques i medioambientals poden actuar com a gran limitador de l’estudi, cal afegir també com a limitació el fet que el participant no vulgui formar part de l’estudi o que el professional de rescat que ha de portar a terme el pla terapèutic no ho faci adequadament.