The theory of quantum electrodynamics (QED) was born out of an attempt to merge Einsteins theory of special relativity and quantum mechanics. Einsteins energy/mass equivalence together with Heisenberg's uncertainty principle allows for particle pairs to be spontaneously created and annihilated in vacuum. These spontaneous fluctuations gives the quantum vacuum properties analogous to that of a nonlinear medium. Although these fluctuations in general does not give note of themselves, effects due to their presence can be stimulated or enhanced through external means, such as boundary conditions or electromagnetic fields. Whereas QED has been very well tested in the high-energy, low-intensity regime using particle accelerators, the opposite regime where the photon energy is low but instead the intensity is high is still to a large degree not investigated. This is expected to change with the rapid progress of modern high-power laser-systems. In this thesis we begin by studying the QED effect of photon-photon scattering. This process has so far not been successfully verified experimentally, but we show that this may change already with present day laser powers. We also study QED effects due to strong magnetic fields. In particular, we obtain an analytical description for vacuum birefringence valid at arbitrary field strengths. Astrophysics already offer environments where QED processes may be influential, e.g. in neutron star and magnetar environments. For astrophysical purposes we investigate how effects of QED can be implemented in plasma models. In particular, we study QED dispersive effects due to weak rapidly oscillating fields, nonlinear effects due to slowly varying strong fields, as well as QED effects in strongly magnetized plasmas. Effects of quantum dispersion and the electron spin has also been included in an extended plasma description, of particular interest for dense and/or strongly magnetized systems.

Vacuum frying is a promising method for preserving the desired color, texture, and flavor of products with high sugar content. Since most vegetables and fruits degrade when processed with traditional frying, vacuum frying is an excellent alternative to high temperature processing. However, in vacuum frying the product should be pre-treated before frying to obtain a better texture. The kinetics of oil absorption and oil distribution in sweet potato chips (total, internal, and surface oil content) was studied so that effectiveness of the de-oiling system could be established. An analysis of product quality attributes (PQA) such as moisture content, oil content, microstructure, diameter shrinkage, and thickness expansion, as well as, color, texture, bulk density, true density, and porosity of chips fried at different temperatures (120, 130, and 140°C) was performed to evaluate the effect of process temperature on the product. The final oil content of the sweet potato chips was 0.178±0.007, 0.178±0.011, and 0.172±0.002 g/g solid for frying temperatures of 120, 130, and 140ºC, respectively. These values were lower (~60% less) than those found in traditionally fried sweet potato chip, which indicates that the de-oiling mechanism is crucial in vacuum frying processing. It was found that the rate of change in PQAs is greatly affected by temperature; however, the final values of bulk density, true density, porosity, diameter shrinkage, and thickness expansion were not affected by temperature. The texture of the samples was affected by temperature, with the chips fried at 140 degrees C being crispier. In terms of color, the L* and color b* values decreased as temperature increased. While color a* was not affected by temperature. In this study, a two-stage frying process was also evaluated to improve the flavor and texture of sweet potato chips. First, a basket filled with the sweet potato slices was submerged into the oil under atmospheric conditions. As soon as the potato slices were partially cooked (1 min), the pressure was lowered to 1.33 kPa (vacuum frying stage) and the product fried for 2 more min. The products were fried at 130 degrees C for different interval of times. Starch gelatinization, texture, moisture content, and oil content were evaluated at each time interval. Sensory analysis was accomplished by using a consumer panel with 50 members. The samples were compared with the on-stage frying and atmospheric frying processes. The two-stage fried chips had better appearance and texture compared to the ones that were only fried under vacuum or atmospheric conditions. The samples were lighter and more yellow than the chips fried under the single-stage process. In vacuum frying, the temperature of the chips does not reach the gelatinization temperature until most of the water is evaporated. Therefore, there is not sufficient moisture content in the product for gelatinization to occur completely. As a result, the product has a glassy texture. In the two stage frying, the atmospheric frying prior to vacuum frying helps the starch to gelatinize thus producing a better product in terms of texture, oil content, and flavor. The atmospheric fried samples were darker in color and had a scorch taste. The degree of starch gelatinization was 21% higher for the two-stage fried samples than the single-stage fried ones. The application of the dual stage enhances the quality of sweet potato chips, improves consumer satisfaction, and reduces the need for space, cost, and any other needs of blanching pre-treatment to the sweet potato manufacturers.

3-(o-(Methylthio)phenyl)-1-phenylprop-2-en-1-one (48) ¡B1-(o-(methylthio)-phenyl)-3-phenylprop-2-en-1-one (49) and 1-(o-(methylthio)phenyl)-3-phenylprop-2-yn-1-one (50) had been studied by means of pyrolysis and photolysis. Under pyrolytic conditions, compound 48 gave phenanthrene (2) as the major product. Both compounds 49 and 50 gave thioflavone (53) as the major product. Under photolytic conditions, compounds 48-50 gave the expected products 2-benzoylbenzo[b]thiophene (51)¡B 2-benzylidenebenzo[b]thiophen-3-one (52) and thioflavone (53), respectively.

1-(o-(Dimethylamino)phenyl)-3-phenylprop-2-en-1-one (62), 3-(o-(dimethylamino)phenyl)-1-phenylpropenone (63) and 1-(o-(dimethyl- amino)phenyl)-3-phenylprop-2-yn-1-one (64) were synthesized and their pyrolytic and photolytic chemistry were studied. Flash vacuum pyrolysis (FVP) of 62 and 64 gave 11H-benzo[a]carbazole (72) and benzo[c]carba-zole (73), FVP of 63 gave phenanthrene (2) and 1-methylquinolin-2(1H)-one (84). Under photolytic conditions, 62 and 64 gave the expected photocyclic products 1-methyl-2-phenylquinolin-4-one (65), while 63 gave the expected photocyclic products (1-methyl-1H-indol-2-yl)phenyl-methanone (66).

1. Generation of nitrenes by means of photolysis of arylmethylazides and its derivatives have been studies. Pyrolysis of 2-azidomethylthiophene¡]44a¡^ gave 2-thiophenecarboxaldehyde¡]77a¡^and (2-thienylmethylidene)-2-thienylamine¡]45a¡^, and pyrolysis of 2-azidomethylbenzo[b]thiophene¡]44b¡^gave the corresponding products. Pyrolysis of 2-azido-1-(2-thienyl)ethanone¡]52a¡^gave 2-thiophenecarboxaldehyde¡]77a¡^, 2-acetylthiophene¡]80a¡^and 2-(thiophene-2-carbonyl)amino-1-(2-thienyl)ethanone¡]83a¡^, and pyrolysis of 2-azido-1-(2-benzo[b]thienyl)ethanone¡]52b¡^gave the corresponding products. 2. Pyrolysis of 3-cyclohexeno[b]furylmethyl benzoate¡]35¡^gave cyclohexeno-4-methylenecyclobuten-3-one¡]25¡^via highly reactive carbene intermediate. At high temperature, compound 25 can continue the reaction of elimination and ring opening to give benzene¡]43¡^, fulvene¡]46¡^, 2-ethylnylcyclohex-1-ene carbaldehyde¡]44¡^ and 4,5-dimethylenecyclopent-2-enone¡]45¡^.

¤@. Photolysis of 2-azido-1-(2- pyridyl)ethanone (68),2-azido-1-(3-pyridyl)ethanone) (69),2-azido-1-(1-methyl-2-pyrryl)ethanone (53) and 2-azido-1-(1-methyl-3-indo yl)ethanone gave Norrish products (71, 7 3-76), (84-86, 89), (92-94) and (93, 95-98). ¤G. Pyrolysis of 2-(azidomethyl)pyridine (9) and 4-(azidomethyl)pyr idine (10) gave the expected products 1,3,5-tri-2-pyridyl-2,4-diaza-1,4-pentadiene (13) and 1,3,5-tri-4-pyridyl-2,4-diaza-1,4-pentadiene (21). ¤T. Pyrolysis of 2-cyclohexeno[b]furylmethyl benzoate (31) gave 2-methylbenzo[b]- furan (40) and benzene products.

¤@¡BPyrolysis of 2-azido-1-(4-methoxyphenyl)ethanone (69) and 2-(2-azidoethyl)furan (85) gave nitrene intermediate to study. There is 2-(4-methoxybenzoyl)-4-(4- methoxyphenyl)imidazole (81) ¡B2-(4-methoxybenzoyl)-5-(4-methoxyphenyl) imidazole] (81¡¦)¡B2,3-di(4-methoxybenzoyl)-5-(4-methoxyphenyl) pyrazine] (82) and 3,5-di(2-furyl) pyridine (92) for pyrolysis products. ¤G¡BPyrolysis of3-methyl-2-cyclohexen[b] furylmethyl benzoate) (50) gave carbene intermediate to study. There is 2,3-dimethylene cyclohexen[b]furan (59) for pyrolysis products.

We study thoroughly Casimir energy and Casimir force in a rectangular cavity and piston with various boundary conditions, for both scalar field and electromagnetic (EM) field. Using the cylinder kernel approach, we find the Casimir energy exactly and analyze the Casimir energy and Casimir force from the point of view of closed classical paths (or optical paths). For the scalar field, we study the rectangular cavity and rectangular piston with all Dirichlet conditions and all Neumann boundary conditions and then generalize to more general cases with any combination of Dirichlet and Neumann boundary conditions. For the EM field, we first represent the EM field by 2 scalar fields (Hertz potentials), then relate the EM problem to corresponding scalar problems. We study the case with all conducting boundary conditions and then replace some conducting boundary conditions by permeable boundary conditions. By classifying the closed classical paths into 4 kinds: Periodic, Side, Edge and Corner paths, we can see the role played by each kind of path. A general treatment of any combination of boundary conditions is provided. Comparing the differences between different kinds of boundary conditions and exploring the relation between corresponding EM and scalar problems, we can understand the effect of each kind of boundary condition and contribution of each kind of classical path more clearly.

This thesis presents the development of a micro-aspirator chip using vacuum expanded microchannels for mechanical characterization of single cells. Mechanical properties of cells can offer valuable insights into the pathogenic basis of diseases and can serve as a biomarker to identify cells depending on disease state, and thus have the potential for use in human disease diagnostic applications. Micropipette aspiration and atomic force microscopy (AFM) are the most commonly used techniques for measuring mechanical properties of single cells. Though powerful and versatile, both methods have two drawbacks. First, micromanipulation of glass micropipettes and AFM tips require expertise and extensive operator skills. Second, the serial manipulation process severely limits the throughput. Although recently reported microfluidic micropipette device showed the potential of microfluidic chip type micropipette aspiration, difficulty in cell trapping and unnatural cell deformation remain to be solved. In order to address these limitations, a high-throughput micro-aspirator chip, which can deliver, trap, and deform multiple cells simultaneously with single-cell resolution without skill-dependent micromanipulation was developed. The micro-aspirator chip is composed of 20 arrays of cell traps and aspiration channels. The principle of cell trapping is based on differences in flow resistance inside the microfluidic channels. Once the first cell trap is filled with a cell, the next cell coming in passes by the trap and is captured in the next trap. After all traps are filled with cells, negative pressure can then be applied to the integrated aspiration channels using hydrostatic pressure. The aspiration channels are positioned at the center of a trapped cell both in vertical and horizontal directions to obtain a good seal just like a traditional micropipette, a design made possible through a vacuum expanded raised microfluidic channel fabrication technique. Device operation was demonstrated using HeLa cells. The cell trapping efficiency was almost 100 percent. Using this device, Young's modulus of 1.3 ± 0.8 kPa (n = 54) was obtained for HeLa cells. Device to device variation was less than 15.2 percent (n = 3), showing good repeatability of the device. No dependence of the Young's modulus on the cell diameter was found.

1. FVP of arylmethylazides (33b¡B34b) via 3,3-sigmatropic rearrangement gave nitrogen-containing heterocyclic compounds (2b¡B4b). FVP of 35 gave 3-benzyl-2-thiophenecarbaldehyde (65) by 1,2 H shift of nitrene 32 followed by hydrolysis. 2. FVP of benzoic 3-(1-propenyl)-2-thiophenecarboxylic anhydride (67) gave 7-hydroxybenzo[b]thiophene (70) and cyclopenteno[b]thiophene (71). Compound 71 is difficult to synthesize by normal organic synthetic methods. The formation of 7-hydroxybenzo[b]thiophene (70) suggesting the existence of 68. 3. FVP of arylimine gave phenanthridine (3)¡B3-methylpyrrolo[2,3-c] quinoline (69) and thieno[2,3-c]quinoline (134). Such a method can synthesize tricyclic products in one step. On the other hand, photolytic study of arylimine gave compounds 156¡B184¡B164¡B180¡B185 and 186.