Titania-based photocatalysts have been extensively studied for the oxidative photodestruction of organic pollutants in wastewaters, releasing non-toxic substances such as CO2, HCl, and water. However, commercial exploitation of this process is limited by the fact that titania is only active under UV irradiation (wavelength below about 388 nm), which is only less than 5% of solar light energy. Sol-gel synthesised catalyst specimens were characterised to determine the correlation between preparation conditions on morphology (XRD, SEM), optical (bandgap energy level) and physicochemical properties (BET surface area, pore volume, acid site density, acid site strength and type) of the photocatalysts. These spesific properties would then be linked to their photoactivity using aqueous aliphatic and aromatic model pollutants. This study has demonstrated that sol-gel synthesised doped titania photocatalysts, especially Pt/TiO2, may be used to effectively degrade non-volatile acids (DL-malic acid, dichloroacetic acid, and p-hydroxybenzoic acid) under visible light and UV irradiation with significant photoactivity suitable for the solar light application of photocatalytic wastewater treatment. A significant drop in band-gap energy was found for all titania sol-gel catalysts doped with Pt, Co, and Ce with values between 1.41 to 1.78 eV. The BET areas of the photocatalysts were also higher (65-117 m2/g) than that of Degussa P25 (50 m2/g). The visible-light photomineralisation of the three pollutants with Pt-TiO2 specimen were further extended to evaluate the effects of major variables in a bubble-column photoreactor on the photodegradation activities. Those major variables were lamp intensity, oxygen concentration, initial pH, catalyst dosage, and inital pollutant concentration. All the three pollutants seemed to follow the Langmuir-Hinselwood model with dual adsorption sites which implicated a bimolecular surface rate-limiting step probably between the adsorbed organic substrate and a surface hydroxyl (or peroxy) radical. A study of the CeyCoxTi(1-x)O3+d perovskite was conducted to investigate the influence of metal composition and pH on the intrinsic optophysical attributes as well as p-hydroxybenzoic acid degradation under UV irradiation. The perovskite UV photoactivities were lower than that of pure TiO2 likely due to excessive loading (metal content) creating new oxide phases act as electron-hole recombination center, regardless better physicochemical attributes of some of the perovskite samples. The role of aging time and calcination temperature on the sol-gel synthesised TiO2 was also explored. Higher calcination temperature (from 250 to 700 0C) resulted in TiO2 photocatalysts with better crystallinity, which is important for OH group formation as active sites for photodegradation. Despite of some advantages from higher temperature preparation, some detrimental effects such as decreased acidity attributes, surface area, and pore volume were also observed. The significant red-shift of sol-gel synthesized TiO2 into visible light, especially for 250 0C specimen since 600 or 700 0C had extremely low activities, has promising implications that this specimen might be used for solar application to substitute Pt-doped TiO2 in order to produce a more cost effective photocatalyst. Aging period (1 to 14 days) did not have any discernible effect on the band-gap value and acid-site density. Even so, the highest acid site strength was obtained with an aging time of 10 days. From the overall perspective, aging time longer than 3 days did not bring noticeable benefits to both catalyst attributes and photoactivities.

L'étude du Soleil dans le domaine ultraviolet est capitale pour la compréhension des phénomènes physiques dont l'atmosphère solaire (où la température peut atteindre le million de Kelvin) est le siège. Les principaux outils disponibles sont les imageurs du disque et de la couronne solaire et les spectromètres. Cependant, l'analyse des données d'imagerie est très vite limitée sans information spectrale et l'association d'imageurs et de spectromètres à fente manque souvent de cohérence spatiale, spectrale ou temporelle. C'est pourquoi la réalisation d'un spectromètre imageur dans l'ultraviolet permettrait une grande avancée pour la physique solaire. Par sa résolution spectrale (en théorie illimitée) et sa capacité à travailler sur de grands champs, le spectromètre imageur à transformée de Fourier est le candidat idéal. Une étude des performances de ce type d'instrument a été réalisée et une maquette de validation du principe de fonctionnement a été construite, alignée et testée à l'Institut d'Astrophysique Spatiale. Cette maquette a permis de mettre en évidence les points durs associés à réalisation et au fonctionnement de ce type d'instrument, en particulier les points durs spécifiques au domaine ultraviolet. Elle constitue une étape dans la construction d'un prototype d'instrument pouvant être embarqué sur un satellite d'observation du Soleil à l'horizon 2015.

Ce travail est une étude exploratoire pour la production d'un anti-UV inorganique de 2ème génération. Deux produits inorganiques ont été synthétisés et testés.<br />Face à un matériau naturel, hétérogène et dynamique tel que le bois, les résultats d'évaluation des performances de photostabilisation sont assez variables non seulement en fonction de l'essence de bois et du type de résine utilisés mais aussi suivant le type de vieillissement. Parallèlement aux tests de vieillissement, l'effet des différents anti-UV sur les propriétés physico-chimiques et mécaniques des films de finition a été étudié en mettant en oeuvre des techniques d'analyse telle que la spectroscopie UV-visible, TMA, RPE et des essais mécaniques. Il apparaît que le pouvoir photoprotecteur joue un rôle important dans les performances de photostabilisation. D'autre part, contrairement aux absorbeurs UV organiques, les inorganiques font augmenter la Tg facilitant ainsi l'apparition des craquelures du film de finition.

La peau constitue la première barrière de défense de l'organisme face aux agressions physiques, chimiques et biologiques de l'environnement. Le rôle protecteur de la peau face aux rayonnements solaires ultraviolets, qui constituent la source majeure de dommages de l'ADN des cellules de l'épiderme, est généralement obtenu par la synthèse de la mélanine. La réponse pigmentaire repose ainsi sur la coopération cellulaire observée principalement entre les mélanocytes et les kératinocytes avoisinants. Les mécanismes moléculaires mis en jeu font intervenir les voies classiques de la pigmentation constitutive, déterminant le phototype propre à chaque individu ainsi qu'une voie de signalisation spécifique de la réponse UV. L'implication de la voie de signalisation p38, stress-dépendante, et du facteur de transcription USF-1 dans la régulation de l'expression du gène Tyrosinase, nous a conduit à étudier le rôle du facteur de transcription dans la réponse pigmentaire (Galibert et al., EMBO, 2001). Un ensemble d'expériences (RT-PCR-Quantitative, Immuno-Précipitation de la chromatine, Transfection transitoire...) réalisé in vitro et in vivo (culture cellulaire ou biopsies humaines) et complété d'une approche génétique utilisant une lignée mélanocytaire invalidé pour le gène USF-1, nous a permis d'établir un modèle de régulation de la pigmentation UV induite (Corre et al., JBC, 2004 ; Corre et al., soumis). Enfin, la mise en évidence d'une nouvelle modification post-traductionnelle de la protéine USF-1 en réponse à un stress, dose et temps dépendant, permet d'envisager un nouveau mode de régulation des gènes régulés par USF- 1 (Corre et Galibert, PCR, 2005 ; Corre et al, en préparation). L'ensemble des données obtenues au cours de ma thèse complètent et précisent la fonction du facteur de transcription USF-1 dans la réponse aux stress et suggère un rôle dans le processus tumoral des mélanomes.

<p>The agriculture in Sweden today uses chemical substances to control vermin, weed</p><p>and diseases. This usage shows through polluted subsoil water and trace elements in</p><p>the food we eat. There’s a risk that additional symptoms will arise in the future.</p><p>Our product Sha Jun, developed in 2006-2007, is an attempt to try and minimize the</p><p>need of chemicals in the agriculture. The idea started with the attempt to minimize the</p><p>usage of pesticides on the cropland. It later developed in an attempt to decrease seed</p><p>disinfectant. The spraying with seed disinfectant today is happening with a rate of 1</p><p>tonne/h. They hope one day to reach the speed of 5 tonnes/h. With our product you</p><p>reach speeds of 17.5 tonnes/h. We also eliminate the need to use the dangerous seed</p><p>disinfectant on the seed before it s stored. The market for our product in Sweden</p><p>consists of approximately 800 potential buyers. These include farms over 200 hectares</p><p>and collection centrals. It will also give ecological framers a change to decrease their</p><p>losses in useless crops. This because our method of treatment is environment-friendly.</p>

No description available.

This paper describes a promising fabrication technique for rapid replication of high aspect ratio microstructured molds for UV embossing. The process involves casting silicone rubber on a microstructured master, replicating an epoxy mold using the PDMS rubber mold and finally, metallizing the surfaces of the epoxy mold by electroless plating nickel (EN). The preliminary study suggests that this technique is feasible for rapid replication of high aspect ratio molds for UV embossing. Uniform molds can be replicated rapidly through this technique making the process economical and accessible. / Singapore-MIT Alliance (SMA)

The organic electronic ion pump (OEIP) is an electrically controlled polymer-based device that has the capability to interact with biological systems down to a single cell level by mimicking neural signalling. This is accomplished by translation of an electrical signal into a chemical output, such as ions and neurotransmitters. Because of the combined spatial and temporal precision, this is a technology with a promising future as an advanced therapeutic device. Depending on the application, the OEIP requires different geometries. Implants that will be used to control on a single cell level require very small dimensions, while for example extracorporeal mounted OIEPs, with only the delivery channel penetrating the skin, require much longer channels. Despite the application, it is necessary to have a good knowledge about the transport and delivery properties and how they change due to the geometry. These properties have been observed as very varying and unstable in early unpublished results, and these findings motivate this project. This project includes photolithographic fabrication and investigation of transport and delivery properties such as effective resistance, efficiency and stability of OEIPs with varying delivery channel lengths and widths. Shorter delivery channels show a consistent but relatively low efficiency. Delamination between different layers of the device is suspected as the cause. Initially, the longer delivery channels show a low functionality, most probably due to poor encapsulation. It is suggested that a soft, water-permeable plastic best encapsulates OEIPs that will be used as a medical implant, while a material impermeable to water, for example a metal, could successfully encapsulate OEIPs operating in air.

A ground-based, zenith-sky, UV-visible triple grating spectrometer was installed at the Polar Environment Atmospheric Research Laboratory (PEARL) in the Canadian High Arctic during polar springtime from 2004 to 2007 as part of the Canadian Arctic ACE (Atmospheric Chemistry Experiment) Validation Campaigns. From the solar spectra, ozone, NO2, and BrO vertical column densities (VCDs) have been retrieved using the DOAS (Differential Optical Absorption Spectroscopy) technique. This spectrometer, the UT-GBS (University of Toronto Ground-Based Spectrometer), was also deployed as part of the fourth Middle Atmosphere Nitrogen TRend Assessment (MANTRA) campaign in Vanscoy, Saskatchewan in August and September 2004. A near-identical spectrometer, the PEARL-GBS, was permanently installed at PEARL in August 2006 as part of the refurbishment of the laboratory by CANDAC (Canadian Network for the Detection of Atmospheric Change). Since then, the instrument has been making continuous measurements, with the exception of during polar night. Vertical columns of ozone and NO2 can be retrieved year-round. During the 2007 sunrise campaign, differential slant column densities (DSCDs) of OClO and VCDs of BrO were also retrieved. Ozone and NO2 DSCDs and VCDs from the UT-GBS were compared to the DSCDs and VCDs from three other UV-visible, ground-based, grating spectrometers that also participated in the MANTRA and Eureka campaigns. Two methods developed by the UV-visible Working Group of the NDACC (Network for the Detection of Atmospheric Composition Change) were followed. During MANTRA, the instruments were found to partially meet the NDACC standards. The comparisons from Eureka were an improvement on the MANTRA comparisons, and also partially met the NDACC standards. In 2007, the columns from the UT-GBS and PEARL-GBS were compared, and were found to agree within the NDACC standards for both species. Ozone and NO2 VCDs from the ground-based instruments were also compared to integrated partial columns from the ACE-FTS (ACE-Fourier Transform Spectrometer) and ACE-MAESTRO (ACE-Measurements of Aerosol Extinction in the Stratosphere and Troposphere Retrieved by Occultation) on board the ACE satellite. ACE-FTS partial columns were found to agree with the ground-based total columns, while the ACE-MAESTRO partial columns were found to be smaller than expected for ozone and larger than expected for NO2.

The agriculture in Sweden today uses chemical substances to control vermin, weed and diseases. This usage shows through polluted subsoil water and trace elements in the food we eat. There’s a risk that additional symptoms will arise in the future. Our product Sha Jun, developed in 2006-2007, is an attempt to try and minimize the need of chemicals in the agriculture. The idea started with the attempt to minimize the usage of pesticides on the cropland. It later developed in an attempt to decrease seed disinfectant. The spraying with seed disinfectant today is happening with a rate of 1 tonne/h. They hope one day to reach the speed of 5 tonnes/h. With our product you reach speeds of 17.5 tonnes/h. We also eliminate the need to use the dangerous seed disinfectant on the seed before it s stored. The market for our product in Sweden consists of approximately 800 potential buyers. These include farms over 200 hectares and collection centrals. It will also give ecological framers a change to decrease their losses in useless crops. This because our method of treatment is environment-friendly.