Degree-per-hour mode-matched micromachined silicon vibratory gyroscopes

The objective of this research dissertation is to design and implement two novel micromachined silicon vibratory gyroscopes, which attempt to incorporate all the necessary attributes of sub-deg/hr noise performance requirements in a single framework: large resonant mass, high drive-mode oscillation amplitudes, large device capacitance (coupled with optimized electronics), and high-Q resonant mode-matched operation. Mode-matching leverages the high-Q (mechanical gain) of the operating modes of the gyroscope and offers significant improvements in mechanical and electronic noise floor, sensitivity, and bias stability. The first micromachined silicon vibratory gyroscope presented in this work is the resonating star gyroscope (RSG): a novel Class-II shell-type structure which utilizes degenerate flexural modes. After an iterative cycle of design optimization, an RSG prototype was implemented using a multiple-shell approach on (111) SOI substrate. Experimental data indicates sub-5 deg/hr Allan deviation bias instability operating under a mode-matched operating Q of 30,000 at 23ºC (in vacuum). The second micromachined silicon vibratory gyroscope presented in this work is the mode-matched tuning fork gyroscope (M2-TFG): a novel Class-I tuning fork structure which utilizes in-plane non-degenerate resonant flexural modes. Operated under vacuum, the M2-TFG represents the first reported high-Q perfectly mode-matched operation in Class-I vibratory microgyroscope. Experimental results of device implemented on (100) SOI substrate demonstrates sub-deg/hr Allan deviation bias instability operating under a mode-matched operating Q of 50,000 at 23ºC. In an effort to increase capacitive aspect ratio, a new fabrication technology was developed that involved the selective deposition of doped-polysilicon inside the capacitive sensing gaps (SPD Process). By preserving the structural composition integrity of the flexural springs, it is possible to accurately predict the operating-mode frequencies while maintaining high-Q operation. Preliminary characterization of vacuum-packaged prototypes was performed. Initial results demonstrated high-Q mode-matched operation, excellent thermal stability, and sub-deg/hr Allan variance bias instability.Ph.D.Committee Chair: Dr. Farrokh Ayazi; Committee Member: Dr. Mark G. Allen; Committee Member: Dr. Oliver Brand; Committee Member: Dr. Paul A. Kohl; Committee Member: Dr. Thomas E. Michael

Molecular mechanism for the regulation of zinc transport by protein kinase CK2

Breast and prostate cancers are the most common cancers in Australian women and men, respectively. The dysregulation of zinc (Zn2+) homeostasis is an intriguing hallmark for both cancers, e.g., hyper-accumulation of Zn2+ in breast cancer compared to normal breast tissue and low level of cellular Zn2+ in prostate cancer in comparison to normal prostate tissue. Such opposite profiles of zinc in breast and prostate cancer cells point to the potential involvement of zinc in cancer development. This study takes advantage of such characteristic feature between breast and prostate cancer cells to explore their molecular details in zinc homeostasis. In this study, protein kinase CK2 (CK2) was firstly analysed in breast and prostate cancer cells, by dissecting the distinct roles of CK2 subunits (CK2α, CK2α’ and CK2β) in zinc homeostasis. Using CK2 inhibitors 4,5,6,7-tetrabromobenzotriazole (TBB) and CX-4945, siRNA-mediated knockdown and zinc ion specific fluorophores (FluoZin-3 AM), this study demonstrated that zinc accumulation was elevated in PC3 and DU145 prostate cancer cells due to knockdown of the gene expression for CK2α’, while the opposite was observed in MCF-7 and MDA-MB-231 breast cancer cells. Furthermore, siRNA knockdown of individual CK2 subunits showed that individual subunits of CK2 have distinct roles in zinc homeostasis in breast and prostate cancer cells. These findings demonstrated that CK2 is indeed involved in zinc homeostasis in breast and prostate cancer cells, as well as that of individual CK2 subunits play distinct roles. The results of this study demonstrated the involvement of CK2 in zinc homeostasis in breast and prostate cancer cells. The RNA-seq dataset confers a holistic view at the molecular level on how the cancer cell responds to the extracellular zinc exposure. The findings of this study provide molecular insights into zinc homeostasis of breast and prostate cancer cells. As zinc is critical for the structure and function of ~3000 human proteins, the molecular details described in this thesis should open multitudes of avenues for cancer research and anti-cancer drug development

Characterization of Chickpea Germplasm

In plant breeding, genetic diversity is an important component for crop improvement. An experiment was conducted at Ishurdi, Pabna (Bangladesh) to study the diversity and variability within the core germplasm collection of 93 chickpea accessions, and a total of 13 qualitative and 12 quantitative characteristics were studied. Among the qualitative characteristics more significant variations were observed in plant pigmentation, growth habit, flower color, seed color, seed shape, and texture. A total of 93 accessions were divided into eight clusters. The genotypes in Cluster IV and Cluster VIII were crossed with genotypes in Cluster I and Cluster VII for better yield performance. Correlation co-efficient study was done among the 12 quantitative characters with yield performance of the studied chickpea germplasm. Significant and positive correlation was observed among the days to 50% flowering, branches per plant, pods per plant, seeds per pod, straw yield, but significant and negative correlation was observed among the days to maturity, plant height, canopy width and hundred seeds weight within the yield performance of studied chickpea germplasm. Simultaneously, a more distinguished morphological diversity was found in number of pods per plant, grain yield per plant(g), 100-seed weight (g), harvest index and plant canopy height (cm) among the twelve quantitative traits of 93 chickpea accession. The chickpea accessions BD-6051, BD-6058, BD-6557, BD-6214, BD-6221, BD-6235, BD-6460, BD-6461, BD-6470, BD-6471, BD-6472, BD-6473, BD-6478, BD-6480, BD-6481, 6483, BD-6484, BD-6488, BD- 6491, BD-6500, BD-6505, and BD-6513 could be considered for crop improvement through the future breeding program of chickpea

Hill regions of charged three-body systems

For charged three-body systems, we discuss the configurations and orientations that are admissible for given values of the conserved total energy and angular momentum. The admissible configurations and orientations are discussed on a configuration space that is reduced by the translational, rotational and dilation symmetries of charged three-body systems. We consider the examples of the charged three-body systems given by the helium atom (two electrons and a nucleus) and the compound of two electrons and one positron. For comparison, the well known example of the Newtonian gravitational three-body system is discussed for the scheme presented in this paper first.</p