Calmodulin (CaM) is a calcium-binding protein that has promiscuous regulatory interactions with over three hundred intracellular protein targets. The focus of this study was to characterize the functional role of phosphorylated CaM in vitro and calcium-deficient CaM (Apo-CaM) ex vivo. In the in vitro study, the effect of phosphorylated CaM on the binding and activation of CaM target proteins was analyzed using mammalian Nitric Oxide Synthase (NOS). NOS is an enzyme that catalyzes the conversion of L-arginine to L-citrulline and •NO. In addition, the activation of NOS by modified CaM proteins was also analyzed in the presence of a CaM binding peptide, PEP-19. Protein trafficking experiments were performed ex vivo to extend our understanding of Apo-CaM’s functional role in mammalian cells. The cell lines that were used in this investigation include mouse Embryonic Stem Cells (mESC), Human Umbilical Vein Endothelia Cells (HUVEC) and Human Neuronal Glioma Cells (HNGC). The major finding of this projects are: phosphorylation of selective CaM residues can attenuated NOS activity, electrostatic interactions are important in the activation of iNOS by CaM, and the activation of iNOS by CaM occurs in a calcium-dependent manner

Synthesis of size tunable nanomaterials creates distinct chemo-physical properties. Recently, the popularity of magnetic iron oxide and cerium oxide (CeO2) nanocrystals enables researchers to use magnetic iron oxides (magnetite and ferrites) in size dependent magnetic separation and CeO2 as an automobile exhaust gas catalyst. This research shows production of diameter-controlled monodisperse magnetic iron oxide (ranging from 3 to 40 nm in diameter) and CeO2 (from 3 to 10 nm in diameter) nanocrystals with exceptional narrow diameter distribution (σ<10%). The morphology and composition of the nanocrystals were varied by use of diverse metal precursors, reaction temperature, time, cosurfactants, and molar ratio between metal salt and surfactant. Now the narrow diameter distributions of preformed magnetic iron oxide nanocrystals made it possible to grow diameter controlled uniform CNTs. The correlation between aluminum ferrite nanocrystal diameter and CNT diameter was nearly one. Additionally, we could synthesize the highest percentage (60%) of single walled CNTs from the smallest aluminum ferrite nanocrystals (4.0 nm). Because of the synthesis of uniform nanocrystalline CeO2, we could study diameter dependent antioxidant properties of nanocrystalline CeO2; antioxidant capacity of CeO2 was nine times higher than a known commercial standard antioxidant, Trolox. In addition, the smallest CeO2 nanocrystal (4 nm) decreased the oxidative stress of human dermal fibroblasts (HDF) exposed to hydrogen peroxide. These works suggest better understanding of monodisperse nanocrystal synthetic mechanism and potential uses of the materials, such as high quality CNT growth using magnetic iron oxides as precursor catalysts and the reduction of oxidative stress in cells using monodisperse CeO2 nanocrystal as an antioxidant for reactive oxygen species in biological media.

Calmodulin (CaM) is a calcium-binding protein that has promiscuous regulatory interactions with over three hundred intracellular protein targets. The focus of this study was to characterize the functional role of phosphorylated CaM in vitro and calcium-deficient CaM (Apo-CaM) ex vivo. In the in vitro study, the effect of phosphorylated CaM on the binding and activation of CaM target proteins was analyzed using mammalian Nitric Oxide Synthase (NOS). NOS is an enzyme that catalyzes the conversion of L-arginine to L-citrulline and •NO. In addition, the activation of NOS by modified CaM proteins was also analyzed in the presence of a CaM binding peptide, PEP-19. Protein trafficking experiments were performed ex vivo to extend our understanding of Apo-CaM’s functional role in mammalian cells. The cell lines that were used in this investigation include mouse Embryonic Stem Cells (mESC), Human Umbilical Vein Endothelia Cells (HUVEC) and Human Neuronal Glioma Cells (HNGC). The major finding of this projects are: phosphorylation of selective CaM residues can attenuated NOS activity, electrostatic interactions are important in the activation of iNOS by CaM, and the activation of iNOS by CaM occurs in a calcium-dependent manner

Nitric oxide (NO) is produced in different mammalian tissues by nitric oxide synthase (NOS), which has three isoforms: neuronal NOS (nNOS), endothelial NOS (eNOS), and inducible NOS (iNOS). All NOS isoforms contain two domains, an oxygenase domain and a reductase domain. NO is an important transmitter of information between cells in many physiological processes; however, overproduction of this molecule may lead to health problems. Therefore, selective inhibition of NOS isoforms has useful therapeutic potential for treatment of certain diseases that can appear because of the pathological overproduction of nitric oxide. Producing useful isoform selective-inhibitors that bind to the active site in the oxygenase domain has proven to be difficult when based solely on the structure of these enzymes. Biophysical studies in combination with structural properties should provide better insights into isoform-specific inhibitor development. The first step of this study was to produce and purify truncated versions of NOS isozymes consisting of the oxygenase domain as they contain the active site of the enzyme. As a result of differences between humans and other mammals in the amino acids found in the second and third shells/layers surrounding the active site, all the experiments were performed with genes coding for human proteins. The major result of this project was the development of an Escherichia coli (E. coli) expression system to produce large amounts of pure protein. This system will allow for the testing of inhibitors that bind to the active site of NOS enzymes.

none

Since the discovery of transparent conducting oxide (TCO) thin films¡ATCO has been widely used in optoelectronic devices. To increase the potential application of the TCO, this study aims at growing amorphous TCO thin films which possess visible transparency and high electric conductivity. Up to date, only IGZO exhibits these properties. However, the nature resource of indium, the main material in IGZO, is rare and expensive. In this study, searching for new materials that do not contain In, while manifest high transparent and conductivity is our major challenge. ZnO has an energy band gap of 3.4eV, for which visible photon does not have enough energy to excite the electron in ZnO from the valence band to conduction band. Therefore, it reveals itself as transparent. ZnO materials are relative stable in high temperature and chemical environments and thus a good candidate for been developed into amorphous TCO. The reason for the high conductivity in amorphous IGZO thin films is because the S orbital of In is spherical symmetry and has large radius in which can overlap with the next In ions to form a continuous band for conduction. In this study, a similar strategy is employed by use of the large S orbital of the doping tin (Sn) in ZnO. A ceramic ZnO target for the pulse laser deposition system is partially wrapped with tin foil. The optimum growth condition are searching by tuning oxygen partial pressure, laser energy, the distance between the target and substrate, and substrate temperature.

In this research, we used the zinc oxide (ZnO) which is die pressed and sintered for studying. We want to know the variations of microstructure and luminescence property when we doped 0.2 mol.% Al2O3 or Li2O to ZnO, or sintered under different atmospheres (high purity oxygen, high purity nitrogen, high purity argon). Using X-ray diffractometry (XRD), scanning electron microscope (SEM), and catholuminescence (CL) spectrometry equipped with a SEM to analyze the different samples. The all six samples¡¦ crystal structure didn¡¦t change via XRD. We investigated for the in-gap-level modification using the CL spectrometry. CL analysis results indicated that ZnO emitted UV light, visible light (blue, green, yellow light), and Near-infrared light emissions. The UV light emission was attributed to the two electronic transitions from the donor level of free exciton and Zn interstitial to valence band. The blue light (2.53 eV) emission was attributed to the donor level of oxygen vacancy-related defect. The green light emission was attributed to the electronic transition from the acceptor level of zinc vacancy-related defect.And the yellow light emission was attributed to the O interstitial and Li-related defects. The Near-infrared light may be attributed to the deep levels recombination.

Recently, controlling the shape of nanoparticles during their fabrication has become a new and interesting research area. In fact, the nanoparticle has been proven that its physical properties are strikingly related to the shape of itself. After finding the carbon nanotubes in 1911, more and more nanostructure materials have been synthesized. The radical nano-scale vanadium oxide VO2.24(C12H14N2)0.061 is synthesized by hydrothermal method. VO2.24(C12H14N2)0.061 has various physical properties, and we would focus on it¡¦s magnetic properties in the thesis, including magnetic susceptibility and magnetization. The magnetic susceptibility measurements show that the antiferromagnetic transition occurs at T = 20K ~ 25K, and it has been found the specific transition at T = 265K ~ 275K in some samples. Based on the magnetization data, these materials are ferromagnetic, and the hysteresis loops exhibit unusual steps. Whenever these materials process thermal treatments or not, the steps still exist. In addition, we will analyze the impact of the production date, thermal treatment, and preserved environment to discover more colorful properties of these materials.

In recent years, transparent and conductive layers of some metallic oxide, such as cadmium oxide, indium oxide, tin oxide and zinc oxide, can be used for semiconducting transparent coatings. Transparent electronics are nowadays a crucial technology for the next generation of optoelectronic devices. Zinc oxide (ZnO) is a II-VI compound semiconductor with a wide direct bandgap of 3.37 eV. Therefore, ZnO based transparent thin film transistors (TFTs) have been studied extensively. For the wide variety of applications, numerous ZnO films preparation methods have been attempted. In this thesis, the devices of ZnZrO active channel layers were fabricated by the sol-gel spin-coating method. These ZnZrO TFTs were fabricated by bottom-gate bottom-contact-type TFTs. The Experimental results have shown that the electrical properties of the ZnZrO TFTs are strongly dependent on visible light and ambient oxygen. In addition, in this study, the results concerning the influence of temperature on the electrical properties of ZnZrO TFTs also have been discussed. Finally, except for the application of switch devices, the ZnZrO TFTs by sol-gel spin-coating process exhibits a potential application for gas sensors.

Abstract Matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) is a powerful tool for the analysis of biomolecules such as peptides and proteins and soft ionization technique using the organic matrix. Because of the high concentration of the organic matrix produces high background signals in the low mass range, nanopatticles have been intensively applied in the surface-assisted Laser desorption/ionization-mass spectrometry (SALDI-MS) to reduce the background interferences in the MALDI.-MS. This thesis includes two projects. The first project applied the copper oxide nanorods, which absorbs 337 nm UV laser energy and has the large area, as the matrix for SALDI-TOF MS to detect four large antibiotics, peptides and proteins. The optimized conditions of the four antibiotic drugs were: 1000 £gM of copper oxide nanorods and incubation for 30 minutes to get the best signals. The LODs of the Lasalocid, Monensin, Salinomycin and Narasin are 200 nM, 25 nM, 50 nM and 50 nM, respectively. In addition, in this project, the CuO nanorods also can be mixed with glycerol to enhance the detection sensitivity for peptides and proteins. The second project presents the zinc selenium quantum dots (ZnSe QDs) modified with 3-mercaptopropionic acid (3-MPA) as the matrix and affinity probes in the SALDI-TOF MS. It strengthens the interaction between the gramicidin and zinc selenium quantum dots by electric interaction in the pH 6 phosphate buffer solution according to the pI value of the gramicidin and the pKa of. 3-mercaptopropionic acid. The best sensitivity of the gramicidin can be obtained under the optimized conditions: 50 £gM of zinc selenium quantum dots, 30 minutes incubation time and pH 6 of phosphate buffer solution. The LOD of the gramicidin is 0.08 £gM. This approach also can be successfully applied in the SALDI-TOF MS to enhance the sensitivity of peptides and proteins.