Optical filters and thin film optical devices play an important role in Science and Industry. Several significant applications have emerged in optics, microelectronics and computer technology. In this work, we study some aspects of their design and applications. One class of optical fibers, known as Christiansen filters, are based on scattering phenomena in suspensions of solid particles in a liquid medium. Some new scattering filters in the visible and the near UV regions and their performance characteristics are reported here. Feasibility to fabricate such optical filters in solid matrix form is established. Some applications of these scattering filters are discussed. After an introduction to the optics of homogeneous and isotropic thin films, I discuss the general design of anisotropic thin film media and a scheme implemented to calculate their performance. Optical anisotropy, produced by the growth-induced columnar microstructure in thin films and its effects on the performance of optical filters are studied. Large shifts in the peak wavelength of a typical narrow band filter are predicted. Magneto-optical (MO) thin film media of great importance to erasable optical data storage technology are studied. An approximate technique based on a 2 x 2 matrix formalism is developed to calculate the normal incidence performance of these media. To investigate anisotropic effects, to incorporate more than one magnetic film with arbitrary orientations of magnetization, and to study oblique incidence performance, a completely general 4 x 4 matrix technique is implemented in a computer program. Effects of substrate/superstrate birefringence in the read-out signal of MO media are investigated. Several optimizing design criteria, particularly, the effectiveness in employing appropriate metal or dielectric reflector layers are studied. The influence of the plasma edge of metals in enhancing the polar Kerr rotation of MO media is discussed with illustrations. A contour plot of the Kerr rotation and reflectance is developed to help in the design of these media. An explanation is given for the observation of Kerr rotation enhancement near the plasma reflection edge of the reflector layer adjacent to the active MO layer and in general, where the reflectance spectrum shows a steep gradient.

A series of rapid, high sensitivity capillary electrophoresis (CE) separation systems have been developed for the analysis of biological analytes and systems. A majority of the work has focused on development of novel instrumentation, in which new injection and detection strategies were investigated to improve the sensitivity of fast CE. A novel optical injection interface for capillary zone electrophoresis based upon the photophysical activation of caged dye attached to the target analyte was developed. The primary advantage of this approach is the lower background and background-associated noise resulting from reduced caged-fluorescein emission in conjunction with the high quantum yield of the resulting fluorescein. Improved detection limits were obtained compared to those observed in photobleaching-based optical gating. A primary drawback of photolytic optical gating CE is the lack of available caged-dye analogs with sufficiently fast reaction kinetics for online derivatization. To overcome this limitation, we have developed a chemical derivatization scheme for primary amines that couples the fast kinetic properties of o-phthaldialdehyde (OPA) with the photophysical properties of visible, high quantum yield, fluorescent dyes. The feasibility of this approach was evaluated by using an OPA/fluorescent thiol reaction, which was used to monitor neurotransmitter mixtures and proteins. The utilization of a high power ultraviolet light emitting diode for fluorescence detection in CE separations has been introduced to analyze a range of environmentally and biologically important compounds, including polyaromatic hydrocarbons and biogenic amines, such as neurotransmitters, amino acids and proteins, that have been derivatized with UV-excited fluorogenic labels. To understand cellular chemistry, it is imperative that single cells should be studied. This work was focused on developing CE based method to characterize the cellular uptake of TAT-EGFP. We demonstrated TAT mediated delivery of EGFP protein into HeLa cells and TAT-EGFP loaded single cell was analyzed by CE-LIF to determine the intracellular EGFP content. An application of CE-LIF for the determination of biogenic amine levels in the antennal lobes of the Manduca sexta is also explored and methods were developed to analyze a single antennal lobe dissected from moths. The lobe was digested and contents were labeled with the fluorogenic dye prior to CZE analysis.

With a surge in future demand for hydrogen as a renewable fuel, the specific aim of this study was to develop a novel strategy in photosynthetic hydrogen production from green algae, which is one of the cleanest processes among existing hydrogen-production methodologies currently being explored. The novel strategy designed was a spectral-selective PSI-activation/PSII-deactivation protocol that would work to maintain a steady flow of electrons in the electron transport system in the light-dependent part of photosynthesis for delivery of electrons to hydrogenase for photo-hydrogen production. The strategy would work to activate PSI to assist in driving the electron flow, while partially deactivating PSII to a degree that it would still supply electrons, but would limit its photosynthetic oxygen production below the respiratory oxygen consumption so that an anoxic condition would be maintained as required by hydrogenase. This study successfully showed that the implementation of the spectral-selective PSIactivation/ PSII-deactivation strategy resulted in actual and relatively sustained photohydrogen production in Chlamydomonas reinhardtii cells, which had been dark-adapted for three hours immediately prior to exposure to a PSI-spectral selective radiation, which had a spectral peak at 692 nm, covering a narrow waveband of 681-701 nm, and was applied at 15 W m⁻². The optimal condition for the PSI-spectral-selective radiation (692 nm) corresponded with low cell density of 20 mg chlorophyll L⁻¹ ("chl" henceforth) with cells grown at 25⁰C. At this condition, the PSI-spectral-selective radiation induced the maximal initial hydrogen production rate of 0.055 mL H² mg⁻¹ chl h⁻¹ which statistically the same as that achieved under white light of 0.044 mL H² mg⁻¹ chl h⁻¹, a maximal total hydrogen production of 0.108 mL H² mg⁻¹ chl which significantly exceeded that under white light of 0.066 mL H² mg⁻¹ chl, and a maximal gross radiant energy conversion efficiency for hydrogen production of 0.515 μL H² mg⁻¹ chl L⁻¹ that statistically matched that under white light of 0.395 μL H² mg⁻¹ chl L⁻¹. The study also successfully demonstrated the reversibility feature of the novel strategy, allowing for the cells to alternately engage in photo-hydrogen production and to recover by simply switching on or off the PSI-spectral-selective radiation.

The studies in this thesis research were conducted to investigate if sensitivity to induced cortical spread depression (CSD) or the consequence of a CSD event is affected by sumatriptan induced latent sensitization. Previous studies in our lab showed persistent exposure of sumatripan to rats produced a latent state of sensitization. Using persistent sumatripan exposed rats as a model for medication overuse headache, behavior, electrical stimulation threshold to provoke a CSD event and the immunoreactivity of c-Fos in the trigeminal nucleus caudalis (TNC) were characterized. Current results showed no statistical difference of electrically induced CSD thresholds in anesthetized rats measured at day 20 in sumatripan exposed rats compared with saline treated rats. Topiramate (80 mg/kg, i.p.) used clinically for prophylaxis of migraine headache significantly increased CSD threshold in both saline and sumatriptan infused rats. CSD events appear to be associated with trigeminal vascular system activation in TNC because c-Fos expression significantly enhanced in rats with electrically stimulated CSD events. As compared to saline treated rats, sumatriptan-exposed rats demonstrated a significantly higher number of c-Fos positive cells following the electrically stimulated CSD event. Under environmental stress (bright light), sumatripan exposed rats demonstrated decreased response thresholds to periorbital and hindpaw tactile stimuli (i.e., allodynia) and enhanced c-Fos expression in TNC. A single dose of topiramate (80 mg/kg, i.p.) reversed environmental stress induced allodynia and c-Fos over-activity. Taken together, these results suggest that latent sensitization induced by persistent sumatripan exposure seems not correlated to the threshold of electrically stimulated CSD in current model. However, CSD enhanced the responses of trigeminal system in rats with sumatriptan-induced latent sensitization. The protective effects of topiramate shown in this model may be related to blocking the initiation of CSD events resulting from environmental stimulation as well as inhibiting the consequences of CSD events in primary afferents. These findings correlate with clinical observations of protective effects of topiramate for migraine prophylaxis.

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