Virtually all diurnal birds have tetrachomatic vision based on four different colour receptors. As a result, birds are potentially able to perceive their environment in twice as many colours as humans and four times as many colours compared to most other mammals, which are dichromatic. In addition to the spectrum visible to humans, birds are able to detect ultraviolet (UV) light. Signals with a UV component have been shown to be important to birds both in foraging and colour signalling. Because of the superior colour discrimination of the avian eye, UV sensitivity, but especially owing to its tetrachromacy, we cannot know what birds look like to those that matter, i.e. other birds. In my thesis I describe a new molecular method with which it is possible to identify the vision system of birds only using a small amount of DNA, without the need to keep or sacrifice the animal. It thereby facilitates large screenings, including rare and endangered species. The method has been used to increase the number of species with identified vision system type from 19 to 66. I show that raptors and songbirds have different vision systems, giving songbirds the possibility of a secret channel for colour signalling, and that male songbirds in coniferous forest take advantage of this to be significantly more cryptic to raptors than to females songbirds. I show that gulls have gained a vision system enabling them to detect the UV signals of fish when the fish swim close to the surface. Even though we tend to be rather self-satisfied with the quality of our colour vision, we are colour-blind when compared to birds. My work shows that human colour vision is inadequate for judging animal coloration, and that there is much more going on in bird colour signalling than meets our eye.

This thesis describes and evaluates an optical method utilizing ultra violet (UV) absorbance for on-line monitoring of haemodialysis treatment. Increased efficiency of haemodialysis treatment is considered to correlate to decreased morbidity and mortality when urea clearance (Kt/V) is elevated. However, further improvements have not been achieved at a higher Kt/V. The mortally rate in the haemodialysis population is still high (27% in Sweden). Urea as the clinical marker is under discussion, partly due to urea being non-toxic, but also that the uraemic syndrom is the result of a cumulative retention of innumerable involved compounds. On-line monitoring systems based on urea determination for improved dialysis efficiency have been suggested and developed in different settings over the last two decades, but have not achieved worldwide utilisation as routine clinical equipment. This thesis demonstrates that the UV-technique utilising 280, 285 and 297 nm is capable of estimating dialysis efficiency in therms of Kt/V, nutritional status in terms of protein catabolic rate (PCR), with the same characteristics as existing methods. One novel finding using UV-absorbance with high sampling rates is the on-line visualisation of the clearance process for following variations in clearance caused by clinical events and disturbances as well as during and after adjustments. The fact that the UV-absorbance technique does not measure urea directly but has high correlation to several other both UV-absorbing and not-absorbing solutes makes it suitable to reflect a more overall solute retention process. Finally, a new efficiency parameter based on the calculation of the area under UV- curve (clearance curve), is suggested to reflect the total removal of some solutes. In summary the UV-technique has the potential to be an additional tool to evaluate improvements of dialysis efficiency, which may result in decreased morbidity, longer life span and enhanced quality of life for the haemodialysis patients.

Le rayonnement ultraviolet (UV) est un cancérigène pour lequel peu d'informations sur l'exposition des populations est disponible. L'intensité et les variations de l'exposition au rayonnement UV solaire, principale source d'exposition, a un impact sur la santé mais il est difficile de les surveiller. Le travail de cette thèse a permis de développer un outil pour une estimation quantitative de l'exposition individuelle à l'UV solaire pour l'épidémiologie. Nous avons créé un atlas des moyennes mensuelles d'irradiation journalière en Europe. Certaines données manquantes au niveau des pays nordiques en hiver ont dû être extrapolées. Nous avons vu que la saisonnalité est forte et que la répartition spatiale ne suit pas seulement le gradient de latitude. Par exemple, l'irradiation UV est plus élevée au sud des pays nordiques qu'au centre de l'Europe. Une enquête a été menée dans huit populations européennes afin d'estimer l'exposition individuelle. Ces populations ont des comportements différents vis-à-vis de l'exposition au soleil. Après une étape de modélisation pour estimer les données d'irradiation UV manquantes au nord de la Norvège sur l'ensemble de l'année, nous avons pu quantifier l'exposition chronique et l'exposition pendant les vacances dans trois populations (française, italienne et norvégienne). L'outil développé au cours de cette thèse pourra être utilisé pour de futures études épidémiologiques qui permettront de connaître l'exposition au rayonnement ultraviolet solaire de populations et de mieux comprendre son rôle dans l'étiologie de diverses maladies, telles que les cancers cutanés.

Femtosecond time-resolved photoelectron spectroscopy (fsTRPES) experiments have been used to study the photoelectron energy spectra of simple molecules since the 1980’s. Analysis of these spectra provides information about the ultrafast internal conversion dynamics of the parent ions. However, ultraviolet pulses must be used for these pump-probe experiments in order to ionize the molecules. Since current solid state lasers, such as the Ti:sapphire laser, typically produce pulses centered at 800nm, it is necessary to generate UV pulses with nonlinear frequency mixing techniques. I therefore constructed an optical setup to generate the 3rd and 4th harmonics, at 266.7nm and 200nm, respectively, of a Ti:sapphire (Ti:sa) chirped-pulse amplified (CPA) laser system that produces 35fs pulses centered at 800nm. Thin Beta-Barium Borate (β-BaB2O4 or BBO) crystals were chosen to achieve a compromise between short pulse durations and reasonable conversion efficiencies, since ultrashort pulses are quite susceptible to broadening from group velocity dispersion (GVD). Output energies of around 11μJ and 230nJ were measured for the 266.7nm and 200nm pulses, respectively. The transform limits of the 3rd and 4th harmonic pulse lengths were calculated from their measured spectral widths. We found that the 266.7nm bandwidth was large enough to support sub-30fs pulses, and due to cutting at the lower-wavelength end of the 200nm spectrum, we calculated an upper limit of 38fs. The pulses were compressed with pairs of CaF2 prisms to compensate for dispersion introduced by transmissive optics. Two-photon absorption (TPA) intensity autocorrelations revealed fully compressed pulse lengths of 36 ± 2 fs and 42 ± 4 fs for the 3rd and 4th harmonics, respectively.

Femtosecond time-resolved photoelectron spectroscopy (fsTRPES) experiments have been used to study the photoelectron energy spectra of simple molecules since the 1980’s. Analysis of these spectra provides information about the ultrafast internal conversion dynamics of the parent ions. However, ultraviolet pulses must be used for these pump-probe experiments in order to ionize the molecules. Since current solid state lasers, such as the Ti:sapphire laser, typically produce pulses centered at 800nm, it is necessary to generate UV pulses with nonlinear frequency mixing techniques. I therefore constructed an optical setup to generate the 3rd and 4th harmonics, at 266.7nm and 200nm, respectively, of a Ti:sapphire (Ti:sa) chirped-pulse amplified (CPA) laser system that produces 35fs pulses centered at 800nm. Thin Beta-Barium Borate (β-BaB2O4 or BBO) crystals were chosen to achieve a compromise between short pulse durations and reasonable conversion efficiencies, since ultrashort pulses are quite susceptible to broadening from group velocity dispersion (GVD). Output energies of around 11μJ and 230nJ were measured for the 266.7nm and 200nm pulses, respectively. The transform limits of the 3rd and 4th harmonic pulse lengths were calculated from their measured spectral widths. We found that the 266.7nm bandwidth was large enough to support sub-30fs pulses, and due to cutting at the lower-wavelength end of the 200nm spectrum, we calculated an upper limit of 38fs. The pulses were compressed with pairs of CaF2 prisms to compensate for dispersion introduced by transmissive optics. Two-photon absorption (TPA) intensity autocorrelations revealed fully compressed pulse lengths of 36 ± 2 fs and 42 ± 4 fs for the 3rd and 4th harmonics, respectively.

We present a survey of 72 Seyfert galaxies and quasars observed by the Far Ultraviolet Spectroscopic Explorer (FUSE). Our survey is the largest to date searching for intrinsic UV absorption with high spectral resolution, and is the first step toward a more comprehensive study of intrinsic absorption in low-redshift AGN. We have determined that 72 of 253 available active galactic nuclei (AGN) are viable targets for detection of intrinsic absorption lines. We examined these spectra for signs of intrinsic absorption in the O VI doublet (lambda lamdba 1031.9, 1037.6) and Lyman beta (lambda 1025.7). The fraction of Seyfert 1 galaxies and low-redshift quasars at z<0.15 that show evidence of intrinsic UV absorption is ~50, which is slightly lower than Crenshaw et al. found (60%) based on a smaller sample of C IV absorption in Seyfert 1 galaxies observed with the Hubble Space Telescope (HST). The intrinsic absorption lines are mostly blueshifted with respect to the rest frame of the galaxy, indicating outflow of ionized gas from the AGN. With this new fraction we find a global covering factor of the absorbing gas with respect to the central nucleus of ~0.4. We also provide a deeper analysis of the intrinsic absorption features we found in 35 objects. We have characterized the relation between luminosity and velocity, and examined the relationships between equivalent width, full width at half maximum, velocity and continuum flux. The luminosity/velocity correlation has been explored previously by Laor & Brandt (2002), but at a significantly higher redshift and heavily weighted by Broad Absorption Line quasars. Our survey is for lower redshift and lower luminosity objects, mostly Seyfert galaxies. We have also explored each object with multiple observations for variablity in each of the aforementioned quantities and characterized the variation of equivalent width with continuum flux. Variability for low-z AGN has been seen in the past. In our survey, we find that variability of O VI (lambda lambda 1032, 1038) is less common than for the UV doublets of C IV and N V seen at longer wavelengths, because the O VI absorption is usually saturated. Lyman beta absorption variability is more frequent. In the target-by-target examination we find that Broad Absorption Line (BAL) features and Narrow Absorption Line (NAL) features are related, in that they follow a single relationship between the maximum outflow velocity and the AGN luminosity, and both can be exhibited in similar luminosity objects. IRAS F22456-5125 is one particular Seyfert galaxy that we have selected for modelling due to its interesting assortment of intrinsic absorption lines. It shows a system of five individual kinematic components of absorption features in both O VI lines and in several of the Lyman series lines. We find that each of the components are relatively simple to model and appear to be weak in the X-ray.

<p>Mitochondria are the primary energy producers of the cell and play key roles in cellular signaling, apoptosis and reactive oxygen species (ROS) production. Mitochondria are the only organelles that contain their own genome which encodes for a small subset of electron transport chain (ETC) proteins as well as the necessary tRNAs and ribosomal subunits to translate these proteins. Over 300 pathogenic mitochondrial DNA (mtDNA) mutations have been shown to cause a number of mitochondrial diseases emphasizing the importance of mtDNA maintenance and integrity to human health. Additionally, mitochondrial dysfunction and mtDNA instability are linked to many wide-spread diseases associated with aging including cancer and neurodegeneration. Mitochondria lack the ability to repair certain helix-distorting lesions that are induced at high levels in mtDNA by important environmental genotoxins including polycyclic aromatic hydrocarbons, ultraviolet C radiation (UVC) and mycotoxins. These lesions are irreparable and persistent in the short term, but their long-term fate is unknown. Degradation of mitochondria and mtDNA is carried out by autophagy. Autophagy is protective against cell stress and apoptosis resulting from exposure to mitochondrial toxicants suggesting that it plays an important role in removal of unstable mitochondria that can serve as a source of ROS or initiate apoptotic cell death. Furthermore, dysfunctional mitochondria can be specifically targeted for degradation by the more specific process of mitophagy influenced in part by the processes of mitochondrial dynamics (i.e., fusion and fission). </p><p>The goals of this dissertation were to investigate the long-term fate of helix-distorting mtDNA damage and determine the significance of autophagy and mitochondrial dynamics in removal of and recovery from persistent mtDNA damage. Removal of irreparable mtDNA damage and the necessity of autophagy, mitophagy, fusion and fission genes in removal of this damage were examined using genetic approaches in adult <italic>Caenorhabditis elegans</italic>. In order to investigate the significance of autophagy, fusion and fission genes in recovery from mtDNA damage-induced mitochondrial dysfunction <italic>in vivo</italic>, an experimental method was developed to specifically induce persistent mtDNA damage and mitochondrial dysfunction without persistent nDNA damage in developing <italic>C. elegans</italic>. Additionally, the effect of persistent helix-distorting DNA damage on mitochondrial morphology, mitochondrial function and autophagy was investigated in <italic>C. elegans</italic> and in mammalian cell culture. The rate and specificity of mitochondrial degradation was further examined in cell culture using live-cell fluorescence microscopy and transmission electron microscopy. </p><p>Removal of UVC-induced mtDNA damage was detectable by 72 hours in <italic>C. elegans</italic> and mammalian cell culture, and required mitochondrial fusion, fission and autophagy, providing genetic evidence for a novel mtDNA damage removal pathway. UVC exposure induced autophagy with no detectable effect on mitochondrial morphology in both systems; mitochondrial function was inhibited in the <italic>C. elegans</italic> system but not in the cell culture system in which the degree of mtDNA damage induced was less. Furthermore, mutations in genes involved in these processes as well as pharmacological inhibition of autophagy exacerbated mtDNA damage-mediated larval arrest, illustrating the <italic>in vivo</italic> relevance of removal of persistent mtDNA damage. Mutations in genes in these pathways exist in the human population, demonstrating the potential for important gene-environment interactions affecting mitochondrial health after genotoxin exposure.</p> / Dissertation

In atmospheric environment, synchronized survey of criteria air pollutants and volatile organic compounds (VOCs) are important for ambient air quality measurement. UV-DOAS (Ultra-violet Differential Optical Absorption Spectroscopy) in this research is an optics open-optical monitor based on the ultraviolet and visible-light absorption of gaseous pollutants. This measurement could be employed to examine the spatial average concentration of optical path in the open space, and to monitor criteria air pollutants (including O3, SO2, NO and NO2) as well as VOCs (including benzene, toluene, p-xylene). Aircraft takeoff and landing has serious impacts on the neighboring envvironment of Kaohsiung International Airport. Aircrafts generate two major pollution problems: chemical pollution (leaking flue from engine and fume with particulate and gaseous pollutants from incomplete combustion) and physical pollution (aircraft noise). Most air pollutant emissions from aero engine are generated during aircraft takeoff and landing. The distribution of gaseous pollutants along the runway is a linear pollution source. Restricted by flight safety, it is difficult to monitor and investigate aero engine pollution with traditional stationary monitors. Therefore, open-path monitoring has become a novel tool for research. First, this study investigated the spatial average concentration of air pollutants around the runway of Kaohsiung International Airport and compared with monitoring data from nearby air quality monitoring station to evaluate the performance of the open-path monitoring system. Comparing the stationary monitors with the open-path monitoring showed relatively better correlations on O3 and NO2 than on SO2 and NO, which might be caused by the differences of local emissions. Overall, these two monitoring systems are identical on monitoring regulated pollutants. Furthermore, the open-path monitoring can also examine volatile organic compounds (ex: benzene, p-xylene, and toluene). The open-path monitoring is a practical and reliable monitoring system. It could be considered as one of the ambient air quality standard monitors in the future. Secondly, this study chose the airspace of approach lane, located at west side of the runway 09 of Kaohsiung International Airport, as survey area. The open-path monitoring (OP-SIS) utilized UV-DOAS for sampling and monitoring the air quality of the survey area. It examined, recorded, and analyzed the criteria air pollutants (O3, SO2, NO and NO2) as well as VOCs (including benzene, toluene, p-xylene) to ascertain the impact of aircraft emissions on atmospheric environment. The results suggested that aircraft emissions influenced ambient air quality with high correlation to NO concentration. Additionally, the wind directions of land-sea breeze and monsoon also have influences on the concentration of air pollutants in the study area. In daytime, when wind direction was N or NNE, the variance of NO concentration was consistent with takeoff and landing time points with correlation coefficient of 0.60. After 5-6 minutes of an aircraft passed through the study airspace, the variance of instantaneous concentration of NO climbed up to 30 ppb. The results were contributed to understand the characteristics and sources of aircraft emitted air pollutants. It could provide the authority to have better judgment on reducing air pollutants as well as to assist the maintence and management of ambient air quality surrounding the airports.

Grazing incidence pumping (GRIP) is a scheme to produce x-ray lasers and extreme ultraviolet lithography is a means of lithographic production which requires soft x-rays with a bandwidth of 2% centred at 13,5 nm. In this work firstly a grazing incidence pumping of Ni-like Mo and Ne-like Ti x-ray laser media were simulated by using EHYBRID and a post-processor code coupled to it. The required atomic data were obtained from the Cowan code. Besides, the timing issue needed for amplification purpose in a Ti:Sapphire laser system has been described theoretically. Afterwards, in order to produce soft x-ray lasers for extreme ultraviolet lithographic applications, emission of soft x-rays in the 2% bandwidth centred at 13.5 nm emitted from Sn XII and Sn XIII ions were simulated by using the EHYBRID code for a laser operating at 1064 nm with 1 J of pulse energy and 6 ns of pulse duration. The intensity range that has been investigated is between 1-5 x 1012 W/cm2. Ion fractions of tin ions and line intensities corresponding to different electron temperatures were calculated by using the collisional radiative code NeF.

Zinc oxide, with its direct wide bandgap and high exciton binding energy, is a promising material for optoelectronic devices. Quantum confinement effect and high surface to volume ratio of the nanowires imparts unique properties to them and makes them appealing for researchers. So far, zinc oxide nanowires have been used to fabricate various optoelectronic devices such as light emitting diodes, solar cells, sensors and photodetectors. To fabricate those optoelectronic devices, many different synthesis methods such as metal organic chemical vapor deposition, chemical vapor deposition, pulsed laser deposition, electrodeposition and hydrothermal method have been explored. Among them, hydrothermal method is the most feasible one in terms of simplicity and low cost. In this thesis, hydrothermal method was chosen to synthesize zinc oxide nanowires. Synthesized zinc oxide nanowires were then used as electrically active components in light emitting diodes and ultraviolet photodetectors. Hybrid light emitting diodes, composed of inorganic/organic hybrids are appealing due to their flexibility, lightweight nature and low cost production methods. Beside the zinc oxide nanowires, complementary poly [2- methoxy -5- (2- ethylhexyloxy) - 1,4 -phenylenevinylene] MEH-PPV and poly (9,9-di-n-octylfluorenyl-2,7-diyl) (PFO) hole conducting polymers were used to fabricate hybrid light emitting diodes in this work. Optoelectronic properties of the fabricated light emitting diodes were investigated. Zinc oxide emits light within a wide range in the visible region due to its near band edge and deep level emissions. Utilizing this property, violet-white light emitting diodes were fabricated and characterized. Moreover, to take advantage over the responsivity of zinc oxide to ultraviolet light, ultraviolet photodetectors utilizing hydrothermally grown zinc oxide nanowires were fabricated. Single walled carbon nanotube (SWNT) thin films were used as transparent electrodes for the photodetectors. Optoelectronic properties of the transparent and flexible devices were investigated. A high on-off current ratio around 260000 and low decay time about 16 seconds were obtained. Results obtained in this thesis reveal the great potential of the use of solution grown zinc oxide nanowires in various optoelectronic devices that are flexible and transparent.