Dissertations / Theses: 'Ultraviolet radiation'

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Löfgren, Stefan. "Cataract from ultraviolet radiation /." Stockholm : Karolinska Univ. Press, 2001. http://diss.kib.ki.se/2001/91-7349-065-2/.

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Podskochy, Alexander. "Ultraviolet radiation and cornea /." Stockholm : Karolinska institutet, 2002. http://diss.kib.ki.se/2002/91-7349-118-7/.

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Tenkate, Thomas D. "Ultraviolet radiation exposure of welders." Thesis, Queensland University of Technology, 1994. https://eprints.qut.edu.au/36715/1/36715_Digitised%20Thesis.pdf.

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Ultraviolet radiation (UVR) is a by-product of the welding process and is emitted by the arc formed between the electrode and the base metal. Exposure to UVR can produce acute and chronic effects on the eyes and skin, including photokeratitis and erythema (acute), and pterygium and skin cancer (chronic). The measurement of UVR can be used to determine the level of hazard posed by a particular source. The personal UVR exposure levels of a group of welders and nearby workers was estimated using a photosensitive polymer film, polysulphone. The polysulphone film was attached to eye protection, the workers clothing and also placed throughout the workarea. The estimated ocular exposures of all subjects were found to exceed the eight-hour maximum permissible exposure limit. As the main UVR protective measure for welders is a welding helmet, the degree of protection afforded by a range of helmets was investigated in a laboratory experiment. Radiation was found to be reflected off the filter and toward the eye after entering through: (1) an opening between the edge of the shield and the side of the face, and (2) an opening between the top lip of the shield and the top of the head. The results of this study suggest that welders require ocular protection in addition to welding helmets, and that all exposed skin surfaces of workers in a welding environment should also be protected.

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Li, Xiang. "Computational analysis of ultraviolet reactors /." Online version of thesis, 2009. http://hdl.handle.net/1850/11175.

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Mitchell, Kirsten Margaret Hilla. "Tropospheric ultraviolet radiation, photolysis and clouds." Thesis, Imperial College London, 2001. http://hdl.handle.net/10044/1/8622.

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Solomon, Cam Charles. "Melanoma and lifetime ultraviolet radiation exposure /." Thesis, Connect to this title online; UW restricted, 2004. http://hdl.handle.net/1773/10913.

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Sheikh, Umar. "Re-entry radiation aerothermodynamics in the vacuum ultraviolet." Thesis, Châtenay-Malabry, Ecole centrale de Paris, 2014. http://www.theses.fr/2014ECAP0036/document.

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L’un des défis majeurs pour la conception des capsules de rentrée concerne la modélisation des transferts convectifs et radiatifs à la surface du véhicule. A certains points des trajectoires de rentrée super-orbitale, jusqu’à 40% du flux radiatif total émane du domaine spectral VUV (vacuum ultraviolet), or c’est dans ce domaine que les incertitudes sont les plus fortes. Ce haut niveau d’incertitudes est dû en particulier à un manque de données expérimentales fiables. Le rayonnement VUV est en effet difficile à mesurer en raison de la forte absorption de l’air et des optiques utilisées pour sa mesure. Des difficultés d’analyse supplémentaires sont causées par le fort degré d’auto-absorption et par l’élargissement spectral des raies dans le VUV. L’objectif central de cette étude était d’obtenir des spectres d’émission expérimentaux calibrés dans le VUV afin d’étudier les processus physico-chimiques dans la couche de choc qui contrôlent le flux radiatif. Plus précisément, les objectifs étaient de comparer les spectres observés parallèlement et perpendiculairement à la couche de choc, d’étudier les effets sur l’intensité des raies spectrales émises dans le VUV de l’auto-absorption et de l’élargissement spectral en fonction de la profondeur de champ radiatif (épaisseur optique). Les mesures effectuées perpendiculairement et parallèlement à la surface d’une maquette placée dans l’écoulement représentent un premier jeu de données expérimentales calibrées dans le VUV qui seront utiles pour valider les codes de calcul destinés à prédire le flux radiatif incident. Les mesures obtenues pour différentes profondeurs de champ radiatif représentent quant à elles un ensemble de données expérimentales uniques pour la validation des modèles de transport radiatif et des coefficients d’élargissement des raies. Cette étude s’appuie également sur des simulations numériques afin d’évaluer les prédictions d’un solveur d’écoulement couplé à deux schémas cinétiques à travers la comparaison des spectres mesurés avec les spectres simulés par le code radiatif Specair. Pour atteindre ces objectifs, un banc optique a été conçu et mis en place pour mesurer l’intensité du rayonnement VUV produit autour d’une maquette bidimensionnelle émoussée, avec une résolution spatiale suffisante pour résoudre le profil d’émission dans la couche de choc. La résolution spatiale a été choisie de façon à pouvoir effectuer des mesures du rayonnement dans les zones d’équilibre et hors équilibre de la couche de choc. Un deuxième système a été conçu pour obtenir des mesures du rayonnement VUV incident sur la surface de la maquette. Ce système est constitué d’un hublot placé sur la surface de la maquette et d’un miroir logé à l’intérieur de la maquette pour transmettre le rayonnement vers le système de détection. La profondeur du champ radiatif peut être variée en modifiant la longueur de la maquette, ce qui change l’épaisseur de la couche de choc observée. Le tunnel à détente X2 a été utilisé pour créer les écoulements à haute enthalpie nécessaires pour produire les couches de choc émissives. Deux conditions d’écoulement ont été générées pour cette étude de façon à reproduire des vitesses équivalentes de vol de 10 et 12.2 km/s. Le système spectroscopique utilisé pour ces études comprend un spectromètre McPherson NOVA 225 sous vide couplé à une caméra ICCD Andor iStar de réponse renforcée dans le VUV. Un tube optique scellé par une fenêtre en fluorine a été installé pour prolonger le trajet optique sous vide jusqu’à la maquette de façon à éliminer l’absorption par l’oxygène moléculaire. Le système spectroscopique a été calibré in situ avec une lampe à deutérium placée à l’endroit de la couche de choc rayonnante. L’intensité spectrale incidente sur la surface de la maquette, intégrée entre 115 et 180 nm, est de 0,744 W/cm²sr pour une vitesse d’écoulement de 10 km/s et 12,3 W/cm²sr à 12.2 km/s. [...]
A major design challenge for re-entry capsules lies in the modelling of convective and radiative heat transfer to the surface of the vehicle. At certain points on superorbital re-entry trajectories, up to 40% of the total radiative heat flux is contributed by the vacuum ultra-violet (VUV) spectral range and it is in this spectral range that the largest uncertainties lie. The high level of uncertainty in the VUV is a result of a lack of published experimental data due to difficulties encountered in measuring radiation in the VUV, such as strong absorption by most optical materials and air. Additional complexities of the VUV spectral range include its strongly self-absorbing nature and spectral line broadening. The primary goal of this study was to obtain calibrated spectral measurements in the VUV that enable the investigation of physical processes occurring in the shock layer that influence the incident radiative heat flux. In particular, the issues to be investigated were the variation in spectral radiance observed across a shock layer compared to the spectral radiance measured through the surface, the effects of self-absorption on spectral line intensity and the broadening of spectral lines in the VUV as a function of depth of radiating flow field. The measurements made across and through the surface of a model provide the first set of calibrated experimental results for the validation of computational codes used to predict incident radiative heat flux. Measurements made with a varying depth of radiating flow field provide a unique set of experimental data for the validation of radiation transport models and broadening coefficients. This study also used computational simulations to investigate the accuracy of a flow field solver coupled with two reaction rate schemes and compared the spectra produced using Specair with experimentally measured values. To achieve these goals, an optical system was designed to measure the VUV radiative emission produced around a blunt two-dimensional model in a spatially resolved manner across the shock layer. Spatial resolution allowed for spectral measurements to be made in both the equilibrium and non-equilibrium parts of the shock layer. A second optical system was designed to obtain measurements of VUV radiation incident on the surface of the model. This system incorporated a window in the surface with a mirror housed within the model to deflect the radiation out of the test section and into the detection system. To effectively vary the depth of the radiating flow field, the length of a two-dimensional model was varied, changing the depth of the shock layer being observed. The X2 expansion tube was used to create the high enthalpy flows required to produce radiating shock layers. Two flow conditions were created for this study that represented flight equivalent velocities of 10.0 km/s and 12.2 km/s. The spectroscopy system utilized for this study consisted of an evacuated McPherson NOVA 225 spectrometer coupled to an Andor iStar VUV enhanced intensified charge coupled device. An evacuated light tube sealed with a magnesium fluoride window was required to extend the evacuated light path to the model and avoid any absorption by molecular oxygen. An in-situ calibration of the VUV spectroscopy system was conducted using a deuterium lamp located in the position of the radiating shock layer. The integrated incident spectral radiance measured through the surface of the model between 115 nm and 180 nm was 0.744 W/cm2 sr for the 10.0 km/s condition and 12.3 W/cm2sr for the faster 12.2km/s condition. [...]

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Ho, Wing-kwok. "Solar ultraviolet radiation : monitoring, dosimetry and protection /." Hong Kong : University of Hong Kong, 1999. http://sunzi.lib.hku.hk/hkuto/record.jsp?B21583791.

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Mahon, Alexandra Rose. "Ultraviolet absorption detection of DNA in gels." Thesis, Imperial College London, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.298204.

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Meyer, Linda Maren. "Cataract from ultraviolet radiation in the mouse /." Stockholm, 2005. http://diss.kib.ki.se/2005/91-7140-583-6/.

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Ho, Wing-kwok, and 何永國. "Solar ultraviolet radiation: monitoring, dosimetry and protection." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 1999. http://hub.hku.hk/bib/B31222675.

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12

Stefanik, Lydia R. "Literature review of inorganic ultraviolet radiation filters." Kansas State University, 2012. http://hdl.handle.net/2097/14637.

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Master of Science
Department of Chemical Engineering
Larry E. Erickson
The damage that can be inflicted by ultraviolet radiation has gained widespread interest. Traditionally sunscreens are made of organic and inorganic components that block two of the three types of ultraviolet radiation, UVA and UVB. This report is a literature review of several articles that have investigated the effects of inorganic UV filters; specifically titanium dioxide and cerium dioxide. There are concerns about absorption of titanium dioxide into the skin and the adverse reactions that could occur, but it was found that there is little to no absorption. Similarly the photostability of titanium dioxide is a concern; this was found to be remedied in part by a surface treatment to the titanium dioxide. The combination of titanium dioxide and carnauba wax was also studied and found to enhance the properties of both the organic and inorganic filters. Ceria was studied as a possible replacement for titanium dioxide. It was found to have similar ultraviolet shielding properties while minimizing the photocatalytic activity and photocytotoxicity seen in titanium dioxide.

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Steel, Harriet. "Characterising the biological response to ultraviolet radiation." Thesis, Lancaster University, 2016. http://eprints.lancs.ac.uk/83019/.

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Once considered fairly harmless due to its low energy UVA is now considered a class one carcinogen, the ability of UVA alone to induce Non-melanoma skin cancer is well accepted and although more controversial there is now significant evidence from epidemiological studies and animal models to suggest a role for UVA in the development of melanoma. Furthermore due to its high penetrance UVA is thought to play a larger role in photoaging than UVB. Despite this current sum protection methods assess UVA protection only as a ratio of UVA: UVB that is blocked by the sun cream. Therefore it is desirable to have a more biologically relevant method to assess UVA protection offered by a sun cream. The work in this thesis focuses on the identification of a robust biomarker of UVA exposure, with the aim to identify biomarkers of UVA that could be used to assess the protection offered by different sun creams in order to develop a method in assessing protection similar to SPF that is currently used for UVB. The primary focus was on looking at the DNA damage response following UVA irradiation, and the data presented here shows distinct differences in the mechanism underpinning the DNA damage response in directly irradiated cells and in the UVA bystander cells. The response following UVA has also been shown to be distinct to that following UVB irradiation, both in terms of the DDR and apoptosis induction.

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Welsh, Belinda M. "Retinoid augmentation of ultraviolet radiation induced melanogenesis." Thesis, The University of Sydney, 1997. https://hdl.handle.net/2123/27563.

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The capacity of human skin to increase it's pigmentation in response to sunlight is an important protective mechanism employed by the body against the potential harmful effects of excess ultraviolet radiation These include the development of skin cancer and premature aging of the skin. Intense scientific research, particularly over the past two decades, has led to a greater understanding of the biology of the pigment producing cells in the skin, melanocytes, and their secretory product, melanin. Melanocyte function in the skin depends on a delicate and complex interaction with the surrounding skin cells, systemic hormones and external stimuli, especially ultraviolet radiation from the sun.

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Garoli, Denis. "Development of Sensors for Ultraviolet Radiation Monitoring." Doctoral thesis, Università degli studi di Padova, 2008. http://hdl.handle.net/11577/3425004.

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Stratospheric ozone is known to be the most important atmospheric factor determining clear sky UV radiation reaching the Earth's surface. There are, however, other effects that influence the UV radiant energy transfer: cloud cover, aerosols, tropospheric ozone, and other gaseous pollutants. The relationships between various phenomena taking place in the atmosphere are complex and not well known. Therefore, ground based UV measurements are necessary to explore atmospheric changes and resultant effects on the biosphere and on the life. Moreover in this century the human will travel in space and in such environments the UV effects on health and on materials are not yet completely understood. An instrument that can measure one or several effective irradiation from ultraviolet solar emission must have an increasing sensitivity with decreasing wavelength and should be temperature stabilized and long term reproducible, moreover the response of the sensor should be in agreement with the cosine law. These are only some important condition for the design of a good sensor, but how to obtain a particular spectral response that can reconstruct a biological effectiveness? This work regards the development of innovative sensors for biological effective UV measurements and their possible applications in research field on earth and in space environments.

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Llabrés, Comamala Maria Moira. "Phytoplankton cell death induced by solar ultraviolet radiation." Doctoral thesis, Universitat de les Illes Balears, 2008. http://hdl.handle.net/10803/9374.

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En esta tesis se ha demostrado que la radiación ultravioleta induce mortalidad en comunidades de fitoplancton de diferentes áreas del Océano Atlántico, del Mar Mediterráneo y del Océano Antártico. El fitoplancton más pequeño (pico-fitoplancton) muestra mayor sensibilidad a la radiación UV respecto al fitoplancton de mayor tamaño. Este estudio identifica que el crecimiento de las poblaciones del fitoplancton antártico está controlado por la radiación ultravioleta con inhibiciones de biomasas por encima del 80-90%. Se demuestra también que la transferencia de radicales OH, generados por la radiación ultravioleta, desde la atmósfera hacia la superficie del Océano causa mortalidad en comunidades de fitoplancton de aguas tropicales, templadas y antárticas. El trabajo presentado en esta tesis muestra la importancia de la radiación ultravioleta como factor que induce mortalidad en el fitoplancton, su influencia en el balance del crecimiento neto de estas poblaciones, así como las consecuencias que se derivan en la cadena trófica.

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Giroux, Louis. "Photochemistry of ethylene with infrared and ultraviolet radiation." Thesis, University of Ottawa (Canada), 1988. http://hdl.handle.net/10393/20878.

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Manson, Claire. "The genetics of cutaneous sensitivity to ultraviolet radiation." Thesis, University of Edinburgh, 2006. http://hdl.handle.net/1842/29247.

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UVR is present in the sunlight that reaches the Earth, and can also be artificially produced. Artificial sources of UVR are used therapeutically, for the treatment of skin disease such as psoriasis. UVR is a source of DNA damage, and the major causative agent for the development of skin cancers. UV-induced DNA damage can be repaired by a number of DNA repair pathways, principally the nucleotide excision repair (NER) pathway and the base excision repair pathway (BER), preventing DNA lesions from becoming incorporated into the genome. Defects in the genes involved wit NER lead to three, rare, recessive syndromes: Xeroderma pigmentosum (XP), Cockayne’s Syndrome (CS) and Trichothiodystrophy (TTD). Individuals affected with any of these syndromes have varying degrees of photosensitivity, with XP patients also having a greater than 1000 fold increased risk of skin cancer. As UVR is one of the most frequently exposed to sources of DNA damage, and also used as a therapeutic reagent, it would be useful to have a genetic marker which might predict an individual’s response to UVR. Polymorphisms in the genes involved with the NER, BER and other repair pathways will be examined in this thesis, to determine if any are associated with sensitivity to UVR. Sensitivity to UVR will be determined as the level of erythema induced by an incremental range of UV doses in two independent study groups, of 74 and 31 individuals. Erythema will be measured using reflectance spectrophotometry, which is an analytical measure, rather than the widely used minimal erythemal dose (MED).

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Blazeski, Valerie. "The behavioural responses of anurans to ultraviolet radiation." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp04/mq39174.pdf.

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Di, Nuzzo Sergio. "Effects of ultraviolet radiation on cutaneous T cells." [S.l. : Amsterdam : s.n.] ; Universiteit van Amsterdam [Host], 2000. http://dare.uva.nl/document/55618.

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Wong, Terence Hawkin. "Pigmentation and the cutaneous response to ultraviolet radiation." Thesis, University of Edinburgh, 2009. http://hdl.handle.net/1842/3888.

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Variation in pigmentation of hair and skin is one of the most striking forms of human diversity. Human pigmentation and sun sensitivity is a complex trait. The melanocortin 1 receptor gene (MC1R) (OMIM 15555) has been shown to be a key determinant of hair and skin colour. Recently a number of other genes have been implicated in human pigmentation. This thesis presents the relationship between human pigmentary phenotypes and genetic variation at MC1R and 34 other candidate loci from 159 individuals. The relationship between experimentally induced cutaneous erythemal and facultative pigmentary response to UVB radiation and MC1R and other pigmentation genotypes was investigated in a subset of 98 individuals. Some of this work involved the development of novel methods of assaying phenotype. I present a detailed description of human pigmentation and facultative pigmentation with respect to a number of key variables (e.g. sex, site, freckling, skin type) and seek to explain the variation in pigmentation in relation to these factors. The effect of MC1R on hair colour is large, but MC1R explains a smaller amount of the variation for skin colour. I found that a number of loci including MC1R, oculocutaneous albinism type 2 OCA2 (OMIM 611409), KIT oncogene ligand KITLG (OMIM 184745) and the Hermansky-Pudlak syndrome 3 HPS3 (OMIM 606118) are determinants of pigmentary phenotype. Some of these findings are in keeping with previous work and some are novel. I present data showing novel SNPs in genes Hermansky-Pudlak syndrome 3 (HPS3) and KIT ligand (KITLG) to be associated with human skin and hair colour variation. Association of HPS3 to eye colour was also found and has to be confirmed in another population. The possible putative mechanisms for the novel association finding in HPS3 are discussed. I am in the process of confirming these positive significant findings in collaboration with another laboratory in Denmark. Further experiments are proposed to confirm other associations and phenotypes.

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Sekiya, Takashi. "AEROSOL FORMATION FROM ORGANIC GASES BY ULTRAVIOLET RADIATION." Kyoto University, 1987. http://hdl.handle.net/2433/162204.

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Leszczynski, Kirsti. "Advances in traceability of solar ultraviolet radiation measurements." Helsinki : University of Helsinki, 2002. http://ethesis.helsinki.fi/julkaisut/mat/fysik/vk/leszczynski/.

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Lluria-Prevatt, Maria del Carmen. "Melanoma models for chemoprevention and ultraviolet radiation susceptibility." Diss., The University of Arizona, 2001. http://hdl.handle.net/10150/279795.

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Worldwide the incidence rate of melanoma has risen while other cancer trends decrease. Late stages of melanoma carry a severe prognosis and the cancer is one that afflicts young adults relatively frequent. Treatment options are very few and survival rates remain low in metastatic disease. Models for evaluating new treatments, chemoprevention and melanoma progression are needed. The first model system described here involves the use of chemical carcinogenesis to induce melanoma in a transgenic mouse system, the TPras mouse. The analysis of tumors that developed on these mice demonstrates that this model system has genetic alterations that are much like the human disease, namely the loss or alteration of the tumor suppressor p16 protein, increase in Ras protein and altered PKC expression. The in vitro system from the TP-ras mouse is also used to compliment the in vivo studies for the effectiveness of perillyl alcohol (POH) as a chemoprevention agent of melanoma in the TPras mice. The mechanisms of POH activity are a decrease in Ras protein levels as well as ras downstream effectors, Akt and MAPK. POH causes only a slight increase in apoptosis while it greatly diminishes the production of UV induced reactive oxygen species (ROS). The activity of POH in vitro suggests a mechanism for the chemopreventive effect seen with POH in the TPras mice. The second model described herein mimics the human risk factor for melanoma of light pigmentation. An increase in UV induced tumors is demonstrated in the Avy mice, which are a lighter pigmented mouse than the TPras mice. Thymine dimer production in vitro demonstrated only a mild sunscreen effect of the darker pigmented melanocytes. However the evaluation of ROS production induced by UV indicated that the melanocytes from the lighter pigmented mouse were able to produce much greater levels of ROS both from UVB and UVA induction. These studies suggest that oxidative damage may contribute to melanoma susceptibility in lighter pigmented individuals. In summary, this work has validated the Avy and TPras mouse models for studying risk factors and testing chemoprevention agents, respectively, in melanoma.

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Vishvakarman, Devasenapathy. "Occupational exposure to ultraviolet radiation in Central Queensland." Thesis, Queensland University of Technology, 1999.

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Aguilar, Lara Karla. "Effect of ultraviolet/visible radiation processing on the quality of fruit juices." Doctoral thesis, Universitat de Lleida, 2017. http://hdl.handle.net/10803/405804.

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Aquest treball va estudiar la irradiació ultraviolada-visible (UV-Vis) com una alternativa per a la pasteurització de sucs. Els resultats van mostrar que la irradiació ultraviolada no produeix hidroximetilfurfural i es capaç de degradar-lo. Es va proposar un mecanisme de foto-degradació i es van usar diferents models cinètics per descriure la reacció. La foto-degradació de la vitamina C va ser insignificant usant una làmpada d’emissió múltiple. A més, el processament d’UV-Vis va ser efectiu inactivant els enzims polifenoloxidasa i peroxidasa; a major temperatura major inactivació. Mentrestant, la majoria dels paràmetres fisicoquímics van ser pràcticament inalterats i la quantitat inicial de pigments es va reduir. Per tant, el processament d’UV-Vis combinat amb lleu escalfament és una alternativa viable per a la pasteurització de sucs.
Este trabajo estudió la irradiación ultravioleta-visible (UV-Vis) como una alternativa para la pasteurización de zumos. Los resultados demostraron que la irradiación ultravioleta no produce hidroximetilfurfural y es capaz de degradarlo. Se propuso un mecanismo de foto-degradación y se usaron diferentes modelos cinéticos para describir la reacción. Por el contrario, la foto-degradación de la vitamina C fue insignificante usando una lámpara de emisión múltiple. Además, el procesamiento UV-Vis fue efectivo inactivando las enzimas polifenoloxidasa y peroxidasa en zumos; a mayor temperatura, mayor inactivación. Mientras tanto, la mayoría de los parámetros fisicoquímicos fueron prácticamente inalterados y la cantidad inicial de pigmentos fue reducida. Por lo tanto, el procesamiento UV-Vis combinado con un calentamiento suave representa una alternativa viable para la pasteurización de zumos.
This work studied the ultraviolet-visible (UV-Vis) irradiation as an alternative for fruit juice pasteurisation. The results showed that ultraviolet irradiation does not produce hydroxymethylfurfural and is capable of degrade it. A mechanism of photo-degradation was proposed and different kinetic models were used to describe the reaction. On the contrary, the photo-degradation of vitamin C was insignificant using a multi-wavelength emitting lamp. Moreover, the UV-Vis processing was effective inactivating the enzymes polyphenoloxidase and peroxidase in fruit juices. The higher the temperature the higher the inactivation. Meanwhile, most physicochemical parameters were practically unaltered and the initial quantity of pigments was reduced. Therefore, the UV-Vis processing combined with a mild-heating represents a viable alternative for fruit juice pasteurisation.

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Porter, Michael A. "Hyperspectral imaging using ultraviolet light." Thesis, Monterey, California. Naval Postgraduate School, 2005. http://hdl.handle.net/10945/1817.

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The LINEATE IMAGING NEAR ULTRAVIOLET SPECTROMETER (LINUS) instrument has been used to remotely detect and measure sulfur dioxide (SO2). The sensor was calibrated in the lab, with curves of growth created for the 0.29 0.31 Ã¦ - spectral range of the LINUS sensor. Field observations were made of a coal burning plant in St. Johnâ s, Arizona at a range of 537 m. The Salt River Coronado plant stacks were emitting on average about 100 ppm and 200 ppm from the left and right stacks respectively. Analysis of the LINUS data matched those values within a few percent. Possible uses for this technology include remote verification of industry emissions and detection of unreported SO2 sources.

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Tracy, Daniel P. "Vacuum ultraviolet modification of polymers /." Online version of thesis, 1989. http://hdl.handle.net/1850/10954.

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Wassberg, Cecilia. "Ultraviolet Radiation and Squamous Cell Carcinoma in Human Skin." Doctoral thesis, Uppsala University, Department of Medical Sciences, 2001. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-1479.

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Ultraviolet radiation (UVR) is a major risk factor for development of skin cancer. UVR-induced DNA damage and a dysfunctional p53 protein are important steps in the development of squamous cell carcinoman in human skin (SCC). The aim of the present investigation was to analyze incidence trends of SCC in Sweden, quantify the risk of second primary cancer after SCC and further analyze the effects of UVR and p53 protein in human skin in vivo and in vitro. The effect of photoprotection by sunscreens was also evaluated.

We found that the age-standardized incidence rate of SCC in Sweden increased substantially in both men and women during the period 1961-1995, especially in men and at chronically sun-exposed skin sites. Patients with SCC are also at increased risk of developing new primary cancers, especially in the skin, squamous cell epithelium, hematopoietic tissues and respiratory organs. In experimental studies in vivo and in vitro in human skin we observed that repair of UV-induced DNA damage appears to be more efficient in chronically sun-exposed skin despite a less uniform p53 response. Non-sun- exposed skin is more homogeneous with respect to the epidermal p53 response. Keratinocytes in skin exposed frequently to the sun may be prone to react more easily to cytotoxic stress. Two different modalities of photoprotection significantly reduced the amount of DNA damage and the number of p53-positive cells. In addition, we demonstrated that a well-defined system for in vitro culture of explanted skin provides an excellent alternative to in vivo experiments.

In conclusion, this study has increased our knowledge of SCC epidemiology in Sweden and of the effects of artificial and solar UVR and sunscreens on chronically sun-exposed and non-sun-exposed sites, respectively, of human skin.

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Michael, Ralph. "Development and repair of cataract induced by ultraviolet radiation /." Basel ; Stockholm : Karger, 2000. http://diss.kib.ki.se/2000/3-8055-7044-9/.

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Dong, Xiuqin. "Safety limit estimation for cataract induced by ultraviolet radiation /." Stockholm, 2005. http://diss.kib.ki.se/2005/91-7140-451-1/.

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Duthie, M. S. "Local effects of ultraviolet radiation on cutaneous immune responses." Thesis, University of Edinburgh, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.649829.

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Effects of UVR and UCA application were examined in relation to LC frequency within the epidermis. IVA1 (340-400nm) irradiation, or trans-UCA application, did not alter the LC numbers within the exposed site. UVB (280-315nm) irradiation and cis-UCA application depleted LC, and timecourses for LC depletion were established for both treatments. Injection of antibodies against either IL-1b or TNF-a before UVB irradiation or cis-UCA treatment completely abrogated their effects on LC numbers. Thus, the UVB-mediated reduction of LC is dependent on the cytokines IL-1b and TNF-a. Despite reports that UVA1 irradiation protects mice from subsequent immunosuppression by UVB exposure, UVA1 irradiation did not affect the decrease in LC numbers induced by UVB. Despite the differences in effects on LC frequency, both UVA1 and UVB induced an accumulation of DC within lymph nodes draining the site of irradiation. For both irradiation regimens, the accumulation of DC was dependent on IL-1b. This was identified by injecting neutralising IL-1b antibodies before irradiation, which inhibited the accumulation of DC within draining lymph nodes following irradiation. Similar experiments indicated that accumulation of DC following UVB irradiation, but not following UVA1 irradiation, was also dependent upon TNF-a. Induction of cytokines within irradiated skin was examined. UVB exposure increased the expression of IL-10 and TNF-a proteins at the irradiated site. Attempts to identify the source of these cytokines were inconclusive, as both keratinocyte (PAM-212) and melanocyte (B16) cell lines failed to secrete these cytokines following UVB irradiation. Intracellular stores of TNF-a decreased as the dose of radiation increased. The technique of reverse transcription-polymerase chain reaction (RT-PCR) was established to examine expression of cytokine mRNA in irradiated skin. Following UVB irradiation, TNF-a mRNA was upregulated and there was induction of IL-10 mRNA. UVA1 irradiation did not result in such changes. There were also differences in the timecourse of IL-1b mRNA upregulation.

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Horton, Bruce. "An interdisciplinary model of risk from ultraviolet radiation exposure." Thesis, University of East Anglia, 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.405689.

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Phoenix, Gareth Kevin. "Effects of ultraviolet radiation on Sub-Arctic heathland vegetation." Thesis, University of Sheffield, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.322936.

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Fotouhi, Asal. "The role of MTH1 in ultraviolet radiation-induced mutagenesis." Doctoral thesis, Stockholms universitet, Institutionen för molekylär biovetenskap, Wenner-Grens institut, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-113320.

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Ultraviolet radiation (UVR) is known to be highly mutagenic. What types of DNA lesions that are induced by different UVR wavelengths are still a matter of debate. UVR induces mutagenesis mostly by the formation of photoproducts and the induction of reactive oxygen species (ROS). ROS can give rise to mutations via oxidation of nucleotides in the DNA or the nucleotide pool. Oxidized nucleotides in the nucleotide pool can thereby be incorporated into the DNA during replication and ultimately give rise to mutations. MTH1 however, dephosphorylates oxidized nucleotides in the nucleotide pool, in particular 8-oxo-dGTP and 2-OH-dATP, and inhibits their incorporation into the DNA.The aim of the present study was to investigate the role of MTH1 in mutagenesis and cytogenetic damage induced by UVR in a human lymphoblastoid TK6 cell line. The clonogenic survival, mutant frequency and micronucleus frequency were measured following exposure to UVA, UVB and UVC in MTH1-knockdown and wild-type TK6 cells. As a biomarker for oxidative damage the level of intracellular and extracellular 8-oxo-dG was measured in TK6 cells exposed to UVA. The mutational spectra of UVA-induced mutations at the thymidine kinase gene in MTH1-knockdown and wild-type TK6 cells were investigated.The results show that MTH1 protects against UVA and UVB mutagenesis significantly. MTH1, however, has been shown to offer no protection against UVR-induced cytogenetic damage and is therefore suggested to mainly inhibit mutagenesis. The mutational spectra show that GC>AT and AT>GC transitions are the dominant mutation types in cells exposed to UVA.In conclusion, MTH1 protects TK6 cells against mutagenesis induced by longer wavelengths of UVR. This indicates that the nucleotide pool is a significant target in mutagenesis for longer wavelengths of UVR. The type of mutations induced by UVA, GC>AT and AT>GC, can be formed by the incorporation of 2-OH-dATP from nucleotide pool into the DNA. UVA is therefore suggested to induce mutations by induction of oxidized nucleotides such as 2-OH-dATP.

At the time of the doctoral defense, the following paper was unpublished and had a status as follows: Paper 4: Manuscript.

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Almeida, Ana Rita Marques. "Combined effects of ultraviolet radiation and xenobiotics on zebrafish." Master's thesis, Universidade de Aveiro, 2013. http://hdl.handle.net/10773/12624.

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Mestrado em Biologia Aplicada - Microbiologia Clínica e Ambiental
Nowadays, climate changes are an imperative problem and multiple measurements made in the last years showed an increase of all wavelengths of solar radiance, specially the Ultraviolet radiation. In their natural environment organisms are not only affected by biotic and environmental factors, but also by abiotic factors such as xenobiotics. Besides, these both stressors can interact with each other being their combined effect unpredictable (producing additive, synergistic or antagonistic effect). This work aims to studying the combined effect of UV radiation and three xenobiotics: triclosan, potassium dichromate and prochloraz on zebrafish embryos (Danio rerio). Effects were assessed at two levels: i) effects on embryos mortality and ii) effects in the natural bacterial communities of zebrafish embryos. The organisms were exposed to concentrations of each chemical combined with several UV doses. Embryo’ mortality, were observed daily for 96 hours post fertilization (hpf) and natural bacterial communities’ evaluation was performed at 48 hpf. Results showed that different combined effect may occur compromising organism’s survival. Combined exposure of UV radiation with TCS revealed a synergism pattern when the UV radiation is the dominant stressor while PD and PCZ revealed antagonism at low dose levels or when the UV radiation is dominant in the mixture. Zebrafish natural bacterial communities were also affected by UV radiation and chemicals with the change of their structure; however, conclusions about interactive effects were difficult to be drawn because effects were not always translated into changes in the diversity indexes.
Hoje em dia, as alterações climáticas são um problema imperativo e múltiplas medições feitas nos últimos anos mostram um aumento de toda a radiação solar, especialmente a radiação Ultravioleta que chega á superfície da terra afetando todos os organismos expostos. No seu ambiente natural, os organismos não estão apenas sujeitos a fatores bióticos, mas também a fatores ambientais e abióticos como por exemplo os xenobióticos. Além disso, ambos os stressores podem interagir uns com os outros produzindo efeitos imprevisíveis nos organismos (efeitos sinergísticos ou antagonísticos). O presente trabalho tem como objetivo a avaliação dos efeitos combinados da radiação UV e três xenobioticos (triclosan, dicromato de potássio e procloraz) em embriões de peixe zebra (Danio rerio). A avaliação foi feita a dois níveis: i) efeitos na mortalidade de embriões e ii) efeitos a nível das comunidades bacterianas naturais dos embriões. Os organismos foram expostos a várias concentrações de cada químico, combinadas com várias doses de UV. A mortalidade foi registada diariamente durante 96 horas e as comunidades bacterianas naturais foram avaliadas às 48 horas pós fertilização (hpf). Os resultados mostram que diferentes efeitos combinados foram observados, alterando a ecotoxicidade esperada. A exposição combinada da radiação UV com o TCS revelou um patrão sinergístico quando a radiação UV é o stressor dominante, enquanto que, na combinação UV com PD e PCZ observou-se antagonismo a doses baixas ou quando a radiação UV era dominante na mistura. As comunidades bacterianas naturais do peixe zebra também foram afetadas pela radiação UV e químicos, com alterações na sua estrutura. No entanto, foi difícil tirar conclusões relativamente a possíveis interações entre stressors visto que os efeitos observados nem sempre se traduziam em variações no índice de diversidade.

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Spencer, Mary-Jane. "The influence of ultraviolet B radiation on human epidermis." Thesis, University of Edinburgh, 1994. http://hdl.handle.net/1842/20808.

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The aim of this work was to study the relationship between UVB and LC by examining the influence of moderate, suberythemal doses of UVB, such as are used to treat psoriasis, on epidermal LC morphology, numbers and surface expression of CD1a and major histocompatibility class II (MHC II) antigens in human skin. A six week course of UVB irradiation, using our standard therapeutic regimen for the treatment of psoriasis (total doses of UVB ranged from 2.58-5.58 J/cm²), was administered to nine healthy subjects. The morphology and number of LCs, and the distribution and expression of certain LC surface antigens were studied in control and in UVB-irradiated epidermis. The study of LC morphology prior to UVB irradiation, using the technique of confocal laser scanning microscopy, revealed that their dendrites extended mainly in the horizontal plane of the epidermis and dendrite numbers ranged between two and nine per cell. Adjacent LCs were in close apposition, but there was little contact between them The majority of normal unirradiated epidermal LCs expressed HLA-DP, HLA-DQ and HLA-DR antigens, which were demonstrated by quantitative ultrastructural immunogold method using image analysis, although a small proportion either did not express these antigens or expressed them at high surface densities. In conclusion, a true reduction in the number of LCs occurs after UVB exposure which cannot be explained simply by the loss of LC surface antigen expression. These studies have defined the UVB-induced changes in LC morphology, number and antigen expression in normal human skin.

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Hall, Doyle Thomas. "Ultraviolet resonance radiation and the structure of the heliosphere." Diss., The University of Arizona, 1992. http://hdl.handle.net/10150/186043.

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The solar system and heliosphere are embedded in a partially ionized medium flowing past the Sun at about 22 km s⁻¹. The Voyager and Pioneer 10 spacecraft are travelling upstream and downstream respectively, detecting Lyα radiation resonantly scattered from heliospheric hydrogen. None of the probes has encountered the solar wind termination shock, where the supersonic solar wind is believed to decelerate to subsonic speeds. Penetration of H atoms from the local interstellar flow is the principal source of heliospheric H. Solar gravitation, radiation pressure, and ionization processes largely control the H distribution. However, the presence of the solar wind termination shock is predicted to have two additional effects. H-p charge exchange reactions occurring in the hot, post-shock solar wind plasma should both reduce the number of penetrating H atoms and create a population of suprathermal H atoms. Therefore, heliospheric Lyα emission lines should be composed of narrow and wide components, which should be diagnostic of outer heliospheric structure. Previously unpublished Voyager Cruise Maneuver observations obtained between 15 and 40 AU reveal that upstream Lyα intensities fall as r⁽⁻⁰·⁷⁵ ⁺/⁻ ⁰·⁰⁵⁾. Beyond 15 AU downstream, Pioneer 10 Lyα falls as r⁽⁻¹·⁰⁷ ⁺/⁻ ⁰·¹⁾. These trends cannot be simultaneously reproduced using models which do not include the termination shock. The Voyager data suggest an additional source of Lyα in the upstream region beyond 40 AU. This may be due to suprathermal H gas and/or gradients in the H density, both predicted to be associated with the termination shock. A new method of estimating the heliospheric H density between the two Voyager spacecraft is introduced. The results are ambiguous and suffer due to the uncertainty in relative instrumental Lyα sensitivities.

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Dias, Virgínia Dantas. "Radiação ultravioleta e ozônio aplicados como métodos alternativos de desinfecção de efluentes secundários de esgoto sanitário." Universidade de São Paulo, 2001. http://www.teses.usp.br/teses/disponiveis/18/18138/tde-26012017-104753/.

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A cloração é largamente utilizada para a desinfecção de águas de abastecimento e residuárias, porém o potencial de toxicidade da cloração por seus subprodutos torna o processo menos atrativo. O dióxido de cloro surge como alternativa de desinfecção, porém a sua geração envolve reações bastante dependentes das concentrações de reagentes, das condições físico-químicas, podendo gerar também subprodutos prejudiciais à saúde humana. Outras tecnologias alternativas, como o ozônio e a radiação ultravioleta apareceram como processos tecnicamente viáveis. Neste trabalho buscou-se realizar revisão crítica da literatura existente sobre a desinfecção realizada com radiação ultravioleta e ozônio, bem como investigar e interpretar os aspectos relevantes do desempenho da desinfecção de efluentes de esgoto sanitário com ozônio e com radiação ultravioleta na inativação de coliformes totais e coliformes fecais. Na parte experimental avaliou-se as doses de 80, 95 e 120 mg/L e tempos de contato de 20, 30 e 35 minutos para a desinfecção com ozônio. Na desinfecção com radiação ultravioleta, utilizou-se de tempos de exposição de 10, 30, e 60 segundos, mantendo-se a mesma intensidade média de radiação e variando-se a espessura de lâmina líquida. Nos aspectos observados no decorrer desta pesquisa, verificou-se que para as condições analisadas, a desinfecção com radiação ultravioleta mostrou-se como técnica mais simples e eficaz para a inativação de coliformes fecais e coliformes totais quando comparada à ozonização, apresentando assim vários aspectos favoráveis no que concerne ao modo de operação, a influência da qualidade do efluente bruto, ao controle do processo, entre outros.
The Chlorinate is widely used for the disinfection of waste and drinking water, however the toxicity potential by the by-products of chlorinate renders the process less attractive. The chlorine dioxide comes up as a disinfection alternative, but its production involves highly reagent concentration and physical-chemical condition dependant reactions, also being able to create human health hazardous by-products. Other alternative technologies, like ozone and ultraviolet radiation have risen as technically viable processes. It this work, is has been attempted to review critically the existing literature about the effluent disinfection of sanitary waste, using a comparative approach between the disinfection in which ozone and ultraviolet radiation were used, as well as to investigate and interpret the relevant aspects of sanitary waste effluents disinfection with ozone and ultraviolet radiation on the inactivation of otal and fecal coliforms. In the experimental part doses of 80, 95 and 120 mg/L and contact times of 20, 30 and 35 minutes have been evaluated for the ozone disinfection process. For the ultraviolet method, exposure times of 10, 30 and 60 seconds have been used, keeping the same mean intensity of radiation and varying water layer thickness. With regard to the observed of thios research, is has been verified that, for the analyzed conditions, the ultraviolet disinfection has showed the simplest and most effective method of the inactiviation of fecal andtotal coliforms when compared the ozone method, thus showing several favorable aspects concerning the operation mode, the wal effuent quality influence, the process control, among others.

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Sadi, Roberta Kalil. "Estudo da compatibilização e da degradação de blendas polipropileno/poli (3-hidroxibutirato) (PP/PHB)." Universidade de São Paulo, 2010. http://www.teses.usp.br/teses/disponiveis/3/3133/tde-23082010-092455/.

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O presente trabalho desenvolveu um estudo sobre a blenda polimérica Polipropileno/Poli(3-hidroxibutirato) (PP/PHB). Os principais objetivos desta pesquisa foram estudar a compatibilização da blenda PP/PHB, a influência da prévia fotodegradação sobre a biodegradação da blenda e o comportamento individual do PHB frente a fotodegradação. As blendas PP/PHB foram obtidas nas composições 90/10, 80/20, 70/30 e 60/40 (em peso) numa extrusora dupla-rosca. O estudo da compatibilização foi feito para a blenda PP/PHB 80/20 contendo ou não 10% dos seguintes compatibilizantes: polipropileno grafitizado com anidrido maleico (PP-g-MAn), poli(etileno-co-acrilato de metila) (P(E-co-MA)), poli(etileno-co-metacrilato de glicidila) (P(E-co-GMA)) e poli(etileno-co-acrilato de metila-co-metacrilato de glicidila) (P(E-co-MA-co-GMA)). A caracterização dos materiais foi realizada através de análises morfológicas, químicas e ensaios mecânicos (tração e impacto). Os resultados obtidos permitiram classificar a eficácia dos compatibilizantes na seguinte ordem: P(E-co-MA-co-GMA) >> P(E-co-MA) > P(E-co-GMA) PP-g-MAn. A fotodegradação do PHB foi investigada expondo-se este material numa câmara de envelhecimento artificial por 3, 6, 9 e 12 semanas. O efeito da radiação UV no PHB foi monitorado através de mudanças na sua massa molar, estruturas química e cristalina, bem como nas suas propriedades térmicas, morfológicas, óticas, mecânicas e de biodegradação. A radiação UV causou uma série de mudanças em todas as propriedades analisadas. Estes efeitos, entretanto, não se mostraram muito severos e um dos motivos apontados para isso foi a baixa transmitância da radiação UV apresentada pela amostra de PHB estudada, o que gerou um perfil de degradação muito pronunciado neste material. As blendas PP/PHB em todas as suas composições foram submetidas à radiação UV por 2 e 4 semanas e tiveram a sua biodegradabilidade avaliada por ensaios de perda de massa e de respirometria de Bartha (medida da produção de CO2). Os materiais antes e após as diferentes degradações foram caracterizados através de análises químicas, térmicas, morfológicas e de massa molar. Primeiramente, observou-se que, antes de qualquer degradação, a biodegradação da fase PHB foi suprimida dentro das blendas, o que foi atribuído ao PHB constituir a fase dispersa das misturas. A prévia fotodegradação retardou a biodegradação do PHB e acelerou a biodegradação do PP e de todas as blendas PP/PHB. A maior capacidade biodegradativa do PP e das blendas foi relacionada à cisão de cadeia e formação de grupos funcionais oxidados durante a exposição à radiação ultravioleta.
In this work Polypropylene/Poly(3-hydroxybutyrate) (PP/PHB) blend was studied. In particular the compatibilization and the influence of a previous photodegradation on the biodegradation of the blend were investigated. In order to understand the photodegradation of the blends it was also necessary to study the photodegradation of PHB. The compositions of the PP/PHB blends studied ranged from 90/10 to 60/40 (by weight). These blends were obtained using a twin screw extruder. The compatibilization was evaluated using a PP/PHB blend 80/20 containing or not 10% of the following compatibilizers: maleic anhydride grafted polypropylene (PP-g-MAH), poly(ethylene-co-methyl acrylate) (P(E-co-MA)), poly(ethylene-co-glycidyl methacrylate) (P(E-co-GMA)) and poly(ethylene-co-methyl acrylate-co-glycidyl methacrylate) (P(E-co-MA-co-GMA)). The blends obtained were characterized through their morphological, chemical and mechanical properties (tensile and impact tests). The results obtained enabled the classification of the compatibilizers efficiency in the following order: P(E-co-MA-co-GMA) >> P(E-co-MA) > P(E-co-GMA) PP-g-MAH. PHB photodegradability was investigated through its exposure to artificial UV radiation in a weathering chamber for 3, 6, 9 and 12 weeks. The photodegradation effect was followed by changes of molecular weight, of chemical and crystalline structures, of thermal, morphological, optical and mechanical properties, as well as of biodegradability. UV radiation caused several changes in all the properties evaluated, however, these effects were not very severe. These results could be explained in light of the low UV radiation transmittance of the PHB sample studied, which caused a strong degradation profile for this material. PP/PHB blends in all compositions were exposed to UV radiation for 2 and 4 weeks and had their biodegradability evaluated using the weight loss and the Bartha respirometer tests (CO2 production measurement). The materials before and after the different degradations were characterized by chemical, thermal, morphological and molar mass analysis. First, it was observed that, before any degradation, the biodegradation of the PHB phase was suppressed in the blends, most likely due to the fact that PHB was the dispersed phase within the mixtures studied. Previous photodegradation delayed PHB biodegradation and sped up the biodegradation of PP and all PP/PHB blends. The greater biodegradability of PP and blends was attributed to the chain scission and formation of oxidized functional groups taking place during ultraviolet radiation exposure.

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41

Merkt, Frederic. "Generation and spectroscopic applications of coherent extreme ultraviolet (XUV) radiation." Thesis, University of Cambridge, 1992. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.240116.

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Meldrum, Lennox R. "Estimate of lifetime UV exposure for selected workers in South East Queensland." Thesis, Queensland University of Technology, 1998.

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Hansson, Björn. "Laser-Plasma Sources for Extreme-Ultraviolet Lithography." Doctoral thesis, KTH, Physics, 2003. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-3677.

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This thesis describes the development and characterizationof a liquidxenon- jet laser-plasma source forextreme-ultraviolet (EUV) radiation. It is shown how thissource may be suitable for production-scale EUV lithography(EUVL).

EUVL is one of the main candidates to succeeddeep-ultraviolet (DUV) lithography for large-scalemanufacturing of integrated circuits (IC). However, a majorobstacle towards the realization of EUVL is the currentunavailability of a source meeting the tough requirements onespecially power and cleanliness for operation in an EUVLstepper. The liquid-xenon-jet laser-plasma concept has keyadvantages that may make it suitable for EUVL since, e.g., itsplasma consists only of the inert noble gas xenon and since theliquidjet target technology enables plasma operation at largedistances from the source-hardware thereby reducing sputteringand to allowing for high-power operation.

At the beginning of the work described in this thesis, aspatial instability of the liquid-xenon-jet made stableoperation of a plasma at practical distances from the nozzleorifice dicult. However, an invention of a stabilization methodbased on applying localized heating to the tip of thejet-forming nozzle, resulted in stable jet operation. Thelongitudinal droplet stability of a liquid-droplet laser-plasmasource has also been investigated and improved.

Continuous improvements of especially the laser-power toEUV-radiation conversion eciency (CE) and the stability oflaser-plasma operation at large distances (several centimeter)from the nozzle are reported for the liquidxenon- jet laserplasma source. Furthermore, this source is characterizedregarding many parameters relevant for EUVL operationincluding, ion emission from the plasma and related sputteringof nearby components, source size and shape, therepetition-rate limit of the source and non-EUV emission fromthe plasma.

Although the main focus of the thesis has been thedevelopment and characterization of a liquid-xenon-jetlaser-plasma source for production-scale EUVL, the source mayalso be suitable for small field applications that benefit fromthe high potential brightness of the source. A method to scanthe plasma and thus minimize the photon losses whilemaintaining the object plane uniformity was developed.Furthermore, the first operation of a liquidtin- jet laserplasma is reported. Quantitative EUV flux measurements yieldrecord CE, but quantitative contamination measurements alsoindicate that a liquid-tin-jet laser plasma is not likely to beapplicable as a source for EUVL.

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Urmi, Nusrat Jahan. "Cryptosporidium capture and detection of ultraviolet radiation induced DNA damage." Thesis, University of British Columbia, 2017. http://hdl.handle.net/2429/61058.

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Majority of the waterborne outbreaks in USA and Canada are associated with protozoa. Cryptosporidium, an obligate intra-cellular human pathogen, is responsible for more than 50% of these outbreaks and has become one of the major public health concerns as they can survive typical chemical disinfection treatments. Early detection of this parasite in the water and determination of ultraviolet treatment efficacy can play a role in reducing this disease burden. An antibody based capture surface was developed to detect Cryptosporidium oocysts in treated water. The surface was able to capture three different species of Cryptosporidium: C. parvum; C. muris; C. hominis but not E. coli indicating that the capture surface is Cryptosporidium genus specific rather than species specific and the chances of capturing microorganisms other than Cryptosporidium from water are low. IgG3 was selected as better candidate for the capture surface development due to its higher capture efficiency (~84%-90%) compared to that of IgG1 (~54%-74%). Though the oocysts were successfully released in intact form from the capture surface at pH 1.0, it was not possible to reuse the surface because the capture performance decreased after pH treatment. An indirect ELISA protocol was optimized to detect UV induced photoproducts (CPDs) in the DNA of UV treated Cryptosporidium oocysts using cuvettes in a spectrophotometer. Power soil kit was selected as the preferred DNA extraction kit because of its high recovery from low concentration of Cryptosporidium in water with high concentrations of other solids. The optimized ELISA protocol was applied on the samples spiked with different doses (0, 3, 6, 10 and 40 mJ/cm²) of UV irradiated Cryptosporidium oocysts. The signal generated from DNA-antibody reaction resulted in an exponential rise to maximum curve which showed that the absorbance (indication of DNA damage) increased with the increase in UV dose. Adaptation of these techniques for Cryptosporidium detection & UV treatment validation is expected to improve the standards for water quality monitoring, providing the communities with assurance that their water is safe to consume.
Irving K. Barber School of Arts and Sciences (Okanagan)
Biology, Department of (Okanagan)
Graduate

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Velanis, Christos N. "Regulation of transcription by Ultraviolet-B radiation in Arabidopsis thaliana." Thesis, University of Glasgow, 2015. http://theses.gla.ac.uk/6204/.

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Plants are sessile photo-autotrophic organisms and need to adapt constantly to a dynamic environment. Light is of utmost importance for plants to be able to monitor their surroundings. Ultraviolet-B radiation (UV-B; 280-315 nm) is an intrinsic part of sunlight and, depending on the wavelength and the fluence rate, it may be a stressful signal or an “informational” one. The so called photomorphogenic responses of plants to UV-B are largely mediated by the UV-B specific photoreceptor UV RESISTANCE LOCUS 8 (UVR8), which “senses” UV-B via a tryptophan based mechanism. UVR8 is localised in the cytoplasm and the nucleus mainly as a homodimer. Upon UV-B irradiation it splits to its monomers and accumulates in the nucleus where it has been found to interact with the E3 Ubiquitin ligase COP1. In the nucleus UVR8 has been shown to associate with chromatin on loci of UV-B responsive genes, including that encoding for the bZIP transcription factor (TF) ELONGATED HYPOCOTYL 5 (HY5), a key effector of UVR8-dependent signalling pathways. The binding of UVR8 to chromatin appears to take place via interaction with histones (H2B in particular) rather than DNA itself. However, this association with chromatin seems not to be UV-B specific. The above data suggest a mechanistic basis for an assumed function of UVR8 in the regulation transcription. It seems likely that UVR8 interacts with other proteins associated with chromatin to promote remodelling and/or recruits/activates TFs which in turn stimulate transcription of its target genes. The main objective of this study was to address the above working hypothesis.

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MacManus, Liam Francis. "Surface modification studies of polypropylene using ultraviolet radiation and ozone." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp01/MQ32497.pdf.

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Hiriart, Veronique P. "Ultraviolet radiation and primary production by Lake Erie phytoplankton communities." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2000. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape2/PQDD_0013/NQ53496.pdf.

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Pahkala, Maarit. "Evolutionary ecology of ultraviolet-B radiation stress tolerance in amphibians." Doctoral thesis, Uppsala : Acta Universitatis Upsaliensis : Univ.-bibl. [distributör], 2001. http://publications.uu.se/theses/91-554-5081-4/.

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Tobey, Ra'anan Itzhak. "Linear and nonlinear photo-acoustic spectroscopy with extreme ultraviolet radiation." Diss., Connect to online resource, 2006. http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&res_dat=xri:pqdiss&rft_dat=xri:pqdiss:3207721.

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Whiteside, James Roy. "Persistent genomic instability and bystander effects induced by ultraviolet radiation." Thesis, Lancaster University, 2006. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.444640.

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Dissertations / Theses on the topic 'Ultraviolet radiation'

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