HYBRID PHOTOVOLTAIC DEVICES BASED ON ORGANIC SEMICONDUCTING POLYMERS AND INORGANIC NANOSTRUCTURED ELECTRODES

La fotovoltaica orgánica es una tecnología solar emergente que todavía no ha entrado en el mercado. El objetivo de esta tesis ha sido acercar un poco más la industrialización de dicha tecnología mediante el incremento de la eficiencia y la durabilidad de estos dispositivos solares. Para la consecución de dicho objetivo se identificaron las limitaciones existentes y se diseñó una hora de ruta con diversas estrategias para poder superar cada uno de los problemas. Así, mediante un exhaustivo control de la nano morfología del film fotoactivo y la introducción de electrodos nanoestructurados se ha conseguido incrementar la eficiencia. La sustitución de los electrodos estándares por nuevos electrodos basados en óxidos metálicos confiere durabilidad al sistema. Por último, la sustitución del óxido de indio y estaño como electrodo transparente por nanohilos metálicos de plata habilita la posibilidad de fabricar dispositivos solares flexibles de bajo coste.

The promoter of cell growth- and RNA protection-associated SND1 gene is activated by endoplasmic reticulum stress in human hepatoma cells

Background: Staphyloccocal nuclease domain-containing protein 1 (SND1) is involved in the regulation of gene expression and RNA protection. While numerous studies have established that SND1 protein expression is modulated by cellular stresses associated with tumor growth, hypoxia, inflammation, heat- shock and oxidative conditions, little is known about the factors responsible for SND1 expression. Here, we have approached this question by analyzing the transcriptional response of human SND1 gene to pharmacological endoplasmic reticulum (ER) stress in liver cancer cells. Results: We provide first evidence that SND1 promoter activity is increased in human liver cancer cells upon exposure to thapsigargin or tunicamycin or by ectopic expression of ATF6, a crucial transcription factor in the unfolded protein response triggered by ER stress. Deletion analysis of the 5'-flanking region of SND1 promoter identified maximal activation in fragment (-934, +221), which contains most of the predicted ER stress response elements in proximal promoter. Quantitative real- time PCR revealed a near 3 fold increase in SND1 mRNA expression by either of the stress- inducers; whereas SND1 protein was maximally upregulated (3.4-fold) in cells exposed to tunicamycin, a protein glycosylation inhibitor. Conclusion: Promoter activity of the cell growth- and RNA-protection associated SND1 gene is up-regulated by ER stress in human hepatoma cells.

Charge and spin transport in graphene devices

170 p.

El soleamiento en las fachadas, técnicas para su reducción y pre dimensionamiento.

[EU]Lan honen helburu nagusia eraikuntzan gehituko diren argi-babeski sistema mota desberdinak aurkeztea da, bertan ematen den energia kontsumoa murrizteko asmoz. Izan ere, argi naturalaren erabilpen egoki batek eraikinaren efizientzia hobetzera eramango gaitu. Horretarako, ezinbestekoa izango da baliabide hau behar bezala ezagutzea, argitasuna eta beharrezko babesa eskaintzeko, eta ondorioz, energia aurreztea lortzeko. Babes sistema egokiena aukeratu baino lehen, aldez aurretik sortu izan diren argi-babeski mota desberdinak aztertu izan dira. Horrez gain, eguzki erradiazioa neurtzeko metodo grafiko eta analitikoak ere aztertu dira. Ondoren, Ecotect programak eskaintzen dituen simulazioei esker, eguzki erradiazioaren datu zehatzagoak lortzeko asmoz, ikasketa horretan erabiliko den eraikinaren kokapena, orientazioa eta ezaugarriak erabaki dira. Behin prototipoa definituta, programa bidez lau babes sistema mota desberdinak aztertu dira, horrela babesik gabeko eraikinean lortutako datuak alderatzeko. Azterketa Bilbo eta Sevillan egitea erabaki izan da. Izan ere, bi hiriburu hauek klimatologian duten desberdintasuna argi-babeskien aukeraketan duen eragina aztertzeko aukeratu dira, gainera, orientazioak eta argi babeskien dimentsioek ere izan dute zer esana aukeraketa garaian. Horrez gain, argi-babeskiek sortutako itzala ere aztertu izan da. Horrela, sistema hauen jarrera orokorra ikusi daiteke, eta beraz, uda garaian babesteko eta negu garaian eguzki izpiak sartzen uzteko duten ahalmena ikusi da. Bukatzeko, aurretik lortutako datu guztiei esker, eta bai kokapena zein orientazioa kontutan hartuz, babes sistema egokiena aukeratu da, jakinik ezinbestekoa dela argitasuna, babesa eta aurrezte energetikoaren arteko oreka egoki bat lortzea.

Electrochemical fabrication and electronic behavior of polypyrrole nano-fiber array devices

Electrochemically active Polypyrrole (PPy) nano-fiber array device was fabricated via electrochemical deposition method using aluminum anodic oxide (AAO) membrane as template. After alkaline treatment electrochemically active PPy nano-fiber lost electrochemical activity, and became electrochemically inactive PPy. The electronic properties of PPy nano-fiber array devices were measured by means of a simple method. It was found that for an indium-tin oxide/electrochemically inactive PPy nano-fiber device, the conductivity of nano-fiber increased with the increase of voltage applied on the two terminals of nano-fiber. The electrochemical inactive PPy nano-fiber might be used as a nano-fiber switching diode. Both Au/electrochemically active PPy and Au/electrochemically inactive PPy nano-fiber devices demonstrate rectifying behavior, and might have been used for further application as nano-rectifiers. (c) 2005 Elsevier B.V. All tights reserved.