UV radiation is utilized in a number of environmental technologies, most notably for the disinfection of water, air, and surfaces through the use of UVC fluorescent lamps. Recently, our group developed a luminescent material that could emit germicidal UVC simply by irradiating it with a household fluorescent lamp, thus introducing a new type of antimicrobial surface powered by low-intensity visible light. The materials were doped with praseodymium ions (Pr3+) which have the unique capability of converting visible light to higher energy UV using an optical mechanism called upconversion. While visible-to-UV upconversion materials appeared promising for environmental application—particularly because solar irradiation could be used for their activation—their practical application was thwarted by low light conversion efficiencies. Herein we discuss the pursuit of new material forms and modifications designed to improve the efficiency of Pr3+-based upconversion systems. These enabled successful enhancement of antimicrobial activity and led to a proof of concept for upconversion-sensitized TiO2 photocatalysis. Correlations between material properties and optical behavior will be presented, followed by commentary on how these strategies might be used to further advance upconversion systems toward environmental application.

This report presents results from a series of experiments in which YAG samples (undoped, as well as doped with Nd and Cr3+) were exposed to ionizing radiation (gamma rays and UV). These experiments were performed for the purpose of investigating the various phtodarkening processes taking place in these materials in response to the ionizing radiation. The purpose of this investigation was to establish whether and how co-doping YAG with Cr3+ improves the material's resistance to photodarkening due to the ionizing radiation. The experiments tracked time-resolved transmittance of the samples at 1064 nm in immediate response a pulsed exposure to the ionizing radiation, as well as steady-state spectrally-resolved changed in the samples' optical absorption after the irradiation. The investigation revealed a number of photodarkening processes occurring in the samples in response to the ionizing radiation, both transient and permanent. It was further revealed that inclusion of Cr3+ ions in YAG significantly reduces these photodarkening processes, improving the material's radiation resistance. It was observed that materials containing at least 0.5 at% Cr3+ are essentially radiation-hardened, resisting both transient and steady-state changes in transmittance observed in the materials not containing Cr3+.

The use of two online sensors, the S::CAN and the FLD, was used to evaluate the treatment of synthetic wastewater by UV/H₂O₂ advanced oxidation. The UV dose and intensity for the flow through reactor was also determined using H₂O₂ actinometry. The total power of the lamps in the reactor was determined to be 139 W which, with the absorbance of the water, produced a UV dose of 39.4 mJ/cm². It was determined that the S::CAN was unable to differentiate between treatment of a particular water, however it could differentiate between different test waters. The FLD was very sensitive and was able to detect minute variations in treatment of the test water.

No description available.

Photodynamic therapy (PDT) is a cancer treatment method in which a photosensitizer, light of a particular wavelength, and also oxygen are used to destroy cancerous cells. Cancer cells absorb the photosensitizing agent which is injected into the body, and it is triggered to cause cell destruction upon absorption of light. This occurs because of the excitation of the photosensitizer produces reactive oxygen species that induce a cascade of cellular and molecular events in the body. Photosensitizing agents that can photo-cleave DNA at long wavelengths are highly demanded in PDT, because the long wavelengths of light can penetrate through tissue deeply compared to visible light. While most of the photosensitizers are activated at wavelengths less than 690 nm, penetration of light continues to increase at increasing wavelengths. In this thesis, photosensitizers that can be activated to oxidize DNA with long wavelengths of light will be discussed. Using quinoline cyanine dyes, here we report the first example of DNA photocleavage at a wavelength of light above 800 nm.

Porous silicon dioxide thin films were produced via dip-coating and doped with Ag+ by adding AgNO3 to the dipping solution. Nanoparticles were formed within the pores of these films by UV exposure. Nanoparticle formation was confirmed by UV-visible spectroscopy and Transmission Electron Microscopy (TEM). Conductive Atomic Force Microscopy (CAFM) showed that the conductivity of the films decreased upon exposure to UV. This decrease in the conductivity is most likely due to the clustering of charge carriers. Initially, Ag+ ions are attached to negatively charged pore walls in a dense packing network. Upon UV exposure (125 mW @ 266 nm), the Ag+ ions are reduced to Ag metal and agglomerate to form clusters. The agglomeration creates gaps in the film that decrease its conductivity. This ability to tune film conductivity was used to create insulating patterns within conducting films. A calibration mask was placed over the films during UV exposure, and exposed regions with a minimum width of ~2 μm were detected as depressions with insulating behavior. The fabrication of photonic and plasmonic devices is being explored using this method.

Les développements récents des techniques de fabrication de matériaux semi-conducteurs de type III-N comme GaN et AlGaN permettent le développement de photo-détecteurs Schottky et métal-semi-conducteur-métal opérant dans le domaine de l'ultraviolet. Alors que les photo-détecteurs à base de GaN et AlGaN ont un faible bruit et un temps de réponse rapide, l'absence de gain interne est un obstacle majeur à leur utilisation dans des applications qui nécessitent des photo-détecteurs à haute sensibilité. Dans ce travail, nous avons conçu et fabriqué des photo-détecteurs à base d'alliage BAlGaN sous forme de monocouches et de super réseaux réalisés par MOVPE et photo-lithographie. Une caractérisation complète de leurs propriétés électriques et électro-optiques a ensuite été réalisée. Nous montrons que ces nouveaux alliages BAlGaN ont un impact majeur sur les performances des photo-détecteurs étudiés. Nous avons pu réaliser des détecteurs présentant un important gain interne (jusqu'à 3x105) donc avec une sensibilité améliorée, un courant d'obscurité faible (jusqu'à 9 ordres de grandeurs plus faible que dans les détecteurs à base de GaN réalisés), une longueur d'onde de coupure ajustable dans la gamme 260-380, et un temps de réponse deux fois plus rapide que dans les détecteurs à base de GaN réalisés. Finalement, nous proposons une interprétation du mécanisme de gain dans ces nouvelles structures reposant sur l'existence de pièges profonds à électrons et à trous / Recent developments in III-N material growth technology such as GaN and AlGaN made possible to fabricate high performance solar-blind Schottky, and metal-semiconductor-metal based photodetectors operating in the ultraviolet range -based photodetectors. While GaN and AlGaN have low noise and fast response times, the lack of high internal gain is a limitation for their use in applications that require high sensitivity photodetectors. In this work, we have designed and fabricated BAlGaN-based photodetectors. For this, several BGaN monolayer and superlattices were grown using MOVPE and lithography processes followed by a full characterization of their electrical and electro-optical properties. We show that these new BAlGaN alloys have tremendous impact on the performance of these photodetectors. We were able to achieve photodetectors with large internal gain (up to 3x105) and thus improved sensitivity, low dark current (up to nine orders of magnitude lower compared to our own GaN-based photodetectors), tunable cut-off wavelength in the 260-380 nm range, and more than two orders of magnitude reduction in the response time compared to our own GaN-based photodetectors. Finally, we propose an interpretation, based on the existence of deep level electron and hole traps, to explain the different mechanisms at the origin of the internal gain in these new structure

Bengkoang roots (Phacyrhizus erosus) have been used as cosmetics materials, primarily as sun screening and skin whitening materials. Indonesia is a tropical country, which has high sunlight intensities every day. Sunlight, primarily the ultraviolet ray, causes several damages on skin; for examples, sunburn, cancer, and hyperpigmentation. Therefore, the Indonesian people need sun screening and skin whitening preparations to avoid the negative effects of ultraviolet. Up to now, active compounds in bengkoang roots which have skin whitening and sun screening activity have not been discovered yet. Therefore, the study on isolation, structure elucidation, antioxidative and anti-tyrosinase assay of active compounds in bengkoang roots has been conducted. The isolation of active compounds has been carried out by Soxhlet extraction using solvents (petroleum ether, ethyl acetate and butanol) followed by fractionated using column chromatography. The structures of the compounds were elucidated using 1D and 2D NMR spectroscopy and mass spectrometry. 13 compounds were isolated. All compounds have an antioxidative activity with the exceptions of ß-sitosterol and stigmasterol. Three isoflavonoids (i.e. daidzein; daidzein-7-O-ß-glucopyranose; 5-Hydroxy-daidzein-7-O-ß-glucopyranose), and a pterocarpan (i. e. (8,9)-Furanyl-pterocarpan-3-ol) were isolated from the ethyl acetate extract. All compounds showed tyrosinase inhibitory activity with IC50 values from 4.38 to 22.20 mM. The other compounds, i. e. 2-Butoxy-2,5-bis(hydroxymethyl)-tetrahydrofurane from the butanol extract and 4-2-(Furane-2-nyl)ethyl)-2-methyl-2,5-dihydrofurane-3-carbaldehyde from the ethyl acetate after hydrolysis extract have the tyrosinase inhibitory activity with IC50 values of 1.21 mM and 0.20 mM, respectively. Based on the results, it can be concluded that bengkoang root can be used as sun screening and skin whitening materials for cosmetics preparations, because the bengkoang root posseses many compounds which have UV absorption, antioxidative and tyrosinase inhibitory activities. / Die Wurzeln der Bengkoang (Phacyrhizus erosus) werden im Bereich der Kosmetik, speziell zum Schutz vor UV-Strahlung und zum Bleichen der Haut, verwendet. Indonesien ist ein tropisches Land, in dem täglich die Sonne scheint. Die Sonnenstrahlung, insbesondere die UV-Strahlung hat negative Auswirkungen, wie z. B. Sonnenbrand, Krebserzeugung und Hyperpigmentation. Deshalb brauchen die Menschen in Indonesien „sunscreen and whitening“-Kosmetik zum Schutz der Haut vor der Sonneneinstrahlung. Bis heute gibt es keine wissenschaftlichen Beweise, ob Bengkoang Wirkstoffe enthält, die die UV-Strahlung absorbieren und die Haut bleichen können. Ziel der Arbeit war die Suche nach Substanzen mit diesem Eigenschaften. Deshalb stand die Isolierung und Strukturaufklärung von Inhaltstoffen aus Bengkoang-Wurzeln sowie die Analyse der UV-Absorptionsfähigkeit und Analyse der Hautbleichungs-Fähigkeit der gefundenen Verbindungen im Mittelpunkt der Arbeit. Die Hautbleichungs-Fähigkeit wurde durch die Analyse der antioxidativen Aktivität und Tyrosinase-Inhibitor-Aktivität getestet. Aus Extrakten unterschiedlicher Polarität wurden Sekundärstoffe durch unterschiedliche chromatographische Trenn-Methoden (Säulenchromatographie mit verschiedenen stationären Phasen) isoliert, deren Struktur mittels Massen-spektrometrie und ein- und zweidimensionalen Kernresonanz-Spektroskopie-Experimente aufgeklärt würde. Insgesamt wurden 13 Naturstoffe isoliert, von denen 11 die antioxidative Aktivität haben. Nur ß-Sitosterol und Stigmasterol zeigten keine die antioxidative Aktivität. Drei Verbindungen der Isoflavonoid-Gruppe, nämlich Daidzein, Daidzein-7-O-ß-glucopyranose, 5-hydroxy-daidzein-7-O-ß-glucopyranose und eine Verbindung der Pterocarpan-Gruppe, nämlich (8,9)-Furanyl-pterocarpan-3-ol, wurde aus dem Essigsäureethylacetat-Extrakt isoliert. Alle haben starke Tyrosinase-Inhibitions-Aktivität mit IC50-Werten von 4.38 mM bis 22.20 mM. Die andere Verbindungen, nämlich 2-Butoxy-2,5-bis(hydroxymethyl)-tetrahydrofuran aus dem Butanol-Extrakt und 4-(2-(Furan-2-nyl)ethyl)-2-methyl-2,5-dihydrofuran-3-carbaldehyd aus dem Essigsäureethylacetat-Extrakt-nach- Hydrolyse, haben eine Tyrosinase-Inhibitions-Aktivität mit IC50-Werten von 1.21 mM und 0.20 mM. Zusammenfassend kann festgestellt werden, dass Bengkoang viele aktive Verbindungen im Bereich der UV Absorption, antioxidative Aktivität und Tyrosinase-Inhibitions-Aktivität haben. Deshalb kann Bengkoang für Kosmetik, speziell als Material, das vor UV-Strahlung schützt und die Haut bleicht, verwendet werden.

Malgré le nombre important de spécialités pharmaceutiques mises sur le marché, certains patients hospitalisés ne peuvent bénéficier d’un traitement pour lequel aucun dosage et/ou forme pharmaceutique n’est disponible. Dans ce cas, la pharmacotechnie hospitalière peut être autorisée à formuler et contrôler des préparations.L’objectif de ces travaux a été de développer une forme transdermique semi-solide, à partir de véhicules prêts à l’emploi et contenant trois antiémétiques, pour traiter les nausées et vomissements chimio-induits. Pour ce faire, l’ondansétron, la dexaméthasone et l’aprépitant ont été formulés dans cinq véhicules commerciaux de composition liposomale (PLO®, Lipovan®, Pentravan® et Pentravan Plus®) ou phytosomale (Phytobase®). Après avoir protocolisé la formulation, un contrôle qualité a été réalisé sur chaque préparation finie. Il a essentiellement porté sur l’évaluation de la teneur en principes actifs dans les formulations et sur leur homogénéité. Dans ce but une méthode séparative utilisant la CLHP-UV et une méthode basée sur la PLS-UV ont été développées et validées selon les recommandations de la Société Française des Sciences Techniques et Pharmaceutiques pour doser simultanément les trois antiémétiques.Deux études in vitro ont ensuite été mises en œuvre sur des cellules de Franz. La première, menée à l’aide de membranes d’acétate de cellulose, a montré que le PLO® et le Pentravan Plus® sont les véhicules les plus performants pour libérer les trois principes actifs (PA) formulés séparément. La seconde visait à évaluer la perméation des mêmes PA à travers des épidermes de peau d’oreilles de cochon. Elle a mis en évidence les performances du Pentravan Plus® comme véhicule pour l’administration simultanée de l’ondansétron et de la dexaméthasone par voie transdermique. La perméation de l’aprépitant étant trop faible pour envisager son administration par voie transdermique, il n’a pas été intégré à la formulation finale. Différents promoteurs d’absorption ont été évalués afin d’améliorer le passage transcutanée : le tween 20 s’est révélé tout aussi performant que l’éthanol classiquement utilisé pour l’incorporation des PA dans ces véhicules. / Despite the high number of formulations available for a drug on the pharmaceutical market, it can arise that a patient needs a treatment for which none pharmaceutical form or dosage is available. In this case, pharmacy department of the hospital may have to prepare this form, in accordance with health agency.The goal of this work was to develop a semi-solid transdermic formulation from ready for use vehicle and containing three antiemetic drugs for the treatment of chemotherapy induced nausea and vomiting. Hence, ondansetron, dexamethasone and aprepitant have been formulated in five commercial vehicles of liposomal (PLO®, Lipovan®, Pentravan® and Pentravan Plus®) or phytosomal (Phytobase®) composition. After development of a formulation protocol, quality control was carried out on every finished preparation It focused on the evaluation of the content of active ingredients in formulations and their homogeneity. For this purpose a separation method using HPLC-UV and a method based on PLS-UV have been developed and validated according to the recommendations of the French Society of Pharmaceutical Science and Technology to assay the three antiemetics simultaneously.Two in vitro studies were then implemented on a Franz cell. The first, using cellulose acetate membranes, has shown that the PLO® and the Pentravan Plus® are the most efficient vehicles for releasing the three drugs formulated separately. The second one was performed to assess the permeation of the same drug through pig ears skin epidermis. It highlighted the performances of Pentravan Plus® as a vehicle for the simultaneous transdermal administration of ondansetron and dexamethasone. Nevertheless, as permeation of aprepitant is too poor to consider its transdermal administration, it has not been included in the final formulation. Different chemical enhancers were evaluated to improve the transcutaneous passage: tween 20 appeared to be as powerful as ethanol conventionally used for the incorporation of drugs in these vehicles.

Este trabalho é parte de um projeto destinado a criar um equipamento médico, para ser aplicado com o protocolo de crosslinking de colágeno corneano, para o tratamento do ceratocone, do qual resultou o desenvolvimento de um sistema de irradiação UV-A de córneas para a aplicação clínica oftalmológica. O sistema desenvolvido neste trabalho consiste de um circuito de malha fechada, que estabiliza a potência luminosa emitida (com erro global, após a calibração, menor que 20% durante a emissão), possibilita seu ajuste até 5 mW (6,366 mW/\'CM POT. 2\') e permite selecionar a duração da emissão entre 10 s - 30 min. O sistema irradia com pico em 365 nm \'+ OU -\' 15 nm sendo que o design óptico proporciona spots homogêneos para três diâmetros selecionáveis: 10 mm; 8 mm; e 6 mm. O software desenvolvido tem a função de controlar todo o procedimento médico do crosslinking corneano, além de detectar falhas no sistema. Os resultados obtidos neste trabalho possibilitaram a criação de um equipamento robusto, flexível e estável, capaz de competir diretamente com os produtos internacionais comercializados mundialmente. Até a presente data tem-se conhecimento de apenas dois produtos, para mesma finalidade, comercializados em todo mundo, sendo ambos de empresas européias. Desta maneira, o sistema descrito nesta dissertação integra hoje o único aparelho de crosslinking totalmente projetado e produzido com tecnologia nacional. / This work is part of a project to create a medical device to be applied with the protocol for corneal collagen crosslinking for the treatment of keratoconus, which resulted in the development of an UV-A system for corneas irradiation for ophthalmic clinical application. The developed system consists of a closed loop circuit, which stabilizes the emitted light power (with global error, after calibration, less than 20% over the issue), allows its adjust up to 5 mW (6.366 mW/\'CM POT.2\') and allows to select the emission duration between 10 s - 30 min. The system irradiates with a peak wave length at 365 nm \'+ OU -\' 15 nm and the optical design provides homogeneous spots for three selectable diameter: 10 mm, 8 mm and 6 mm. The developed software has the function of controlling the medical procedure of corneal crosslinking, and detect system failures. The results of this work enabled the creation of a robust equipment, flexible, and stable that can compete directly with international products marketed worldwide. Until the present date, there has been aware of only two products for the same purpose, marketed worldwide, both from European companies. Thus, the system described in this dissertation integrates now the only unit of crosslinking completely designed and produced with national technology.