HYPERSPECTRAL IMAGING USING SILICON MICROMACHINED VIBRATORY GRATING SCANNERS

Ph.DDOCTOR OF PHILOSOPH

Parametric amplification in MEMs devices

Master'sMASTER OF ENGINEERIN

Deinococcus geothermalis: The Pool of Extreme Radiation Resistance Genes Shrinks

Bacteria of the genus Deinococcus are extremely resistant to ionizing radiation (IR), ultraviolet light (UV) and desiccation. The mesophile Deinococcus radiodurans was the first member of this group whose genome was completely sequenced. Analysis of the genome sequence of D. radiodurans, however, failed to identify unique DNA repair systems. To further delineate the genes underlying the resistance phenotypes, we report the whole-genome sequence of a second Deinococcus species, the thermophile Deinococcus geothermalis, which at its optimal growth temperature is as resistant to IR, UV and desiccation as D. radiodurans, and a comparative analysis of the two Deinococcus genomes. Many D. radiodurans genes previously implicated in resistance, but for which no sensitive phenotype was observed upon disruption, are absent in D. geothermalis. In contrast, most D. radiodurans genes whose mutants displayed a radiation-sensitive phenotype in D. radiodurans are conserved in D. geothermalis. Supporting the existence of a Deinococcus radiation response regulon, a common palindromic DNA motif was identified in a conserved set of genes associated with resistance, and a dedicated transcriptional regulator was predicted. We present the case that these two species evolved essentially the same diverse set of gene families, and that the extreme stress-resistance phenotypes of the Deinococcus lineage emerged progressively by amassing cell-cleaning systems from different sources, but not by acquisition of novel DNA repair systems. Our reconstruction of the genomic evolution of the Deinococcus-Thermus phylum indicates that the corresponding set of enzymes proliferated mainly in the common ancestor of Deinococcus. Results of the comparative analysis weaken the arguments for a role of higher-order chromosome alignment structures in resistance; more clearly define and substantially revise downward the number of uncharacterized genes that might participate in DNA repair and contribute to resistance; and strengthen the case for a role in survival of systems involved in manganese and iron homeostasis

A comparison of the perceptions of Singapore’s 'holistic' university education amongst STEM and non-STEM undergraduates and its effect on their employability

With growing concerns about the employability of university fresh graduates in Singapore’s public universities, we study what undergraduates think of the Ministry of Education’s (MOE’s) definition and implementation of ‘holistic’ education, and how that impacts their perceptions of employability in Singapore. Using theories of Bourdieu’s cultural and economic capital, and the sociology of expectations, we conducted an online survey and face-to-face interviews with students and Recruitment Industry Experts (RIEs) to identify gaps between undergraduates’ and RIEs’ understandings of employability, and if those gaps could be due to differences in perceptions held by STEM and non-STEM undergraduates. We found no significant gaps in perceptions held between the students and RIEs and STEM and non-STEM undergraduates as students are generally highly aware of the industrys’ requirements. However, their primary motivation to learn does not align with MOE’s goal of instilling a passion for learning, but out of obligation to fulfil their employability requirements.Bachelor of Social Sciences in Sociolog

A 50kHz micromachined electrostatic driven vibratory grating laser scanner

10.1016/j.phpro.2011.06.166Physics Procedia19308-31

The impact of temperature and Wolbachia infection on vector competence of potential dengue vectors Aedes aegypti and Aedes albopictus in the transmission of dengue virus serotype 1 in southern Taiwan

Abstract Background We evaluated the impact of temperature and Wolbachia infection on vector competence of the local Aedes aegypti and Ae. albopictus populations of southern Taiwan in the laboratory. Results After oral infection with dengue serotype 1 virus (DENV-1), female mosquitoes were incubated at temperatures of 10, 16, 22, 28 and 34 °C. Subsequently, salivary gland, head, and thorax-abdomen samples were analyzed for their virus titer at 0, 5, 10, 15, 20, 25 and 30 days post-infection (dpi) by real-time RT-PCR. The results showed that Ae. aegypti survived significantly longer and that dengue viral genome levels in the thorax-abdomen (103.25 ± 0.53–104.09 ± 0.71 PFU equivalents/ml) and salivary gland samples (102.67 ± 0.33–103.89 ± 0.58 PFU equivalents/ml) were significantly higher at high temperature (28–34 °C). The survival of Ae. albopictus was significantly better at 16 or 28 °C, but the virus titers from thorax-abdomen (100.70–102.39 ± 1.31 PFU equivalents/ml) and salivary gland samples (100.12 ± 0.05–101.51 ± 0.31 PFU equivalents/ml) were significantly higher at 22–28 °C. Within viable temperature ranges, the viruses were detectable after 10 dpi in salivary glands and head tissues in Ae. aegypti and after 5–10 dpi in Ae. albopictus. Vector competence was measured in Ae. albopictus with and without Wolbachia at 28 °C. Wolbachia-infected mosquitoes survived significantly better and carried lower virus titers than Wolbachia-free mosquitoes. Wolbachia coinfections (92.8–97.2%) with wAlbA and wAlbB strains were commonly found in a wild population of Ae. albopictus. Conclusions In southern Taiwan, Ae. aegypti is the main vector of dengue and Ae. albopictus has a non-significant role in the transmission of dengue virus due to the high prevalence of Wolbachia infection in the local mosquito population of southern Taiwan