Modification of Polymeric Membranes for Energy Sustainability and CO2 Capture

Ph.DDOCTOR OF PHILOSOPH

Salty: A Diffractive Inquiry of Visceral Knowing and Embodied Aesthetics

This dissertation takes a diffractive, onto-epistemological approach to everyday practices with salt in order to articulate an expanded understanding of meaning making and knowledge production. This research reckons with and challenges dominant modes of knowing that engage a Cartesian perspective to situate knowing as the exclusive domain of the mind in both form and topic of inquiry. This research acts simultaneously as both a direct practice of and metacognition about knowledge production by examining 1. the embodied (including sensory and emotional aspects) and 2. the relational (including interpersonal and socio-cultural) dimensions of experience as visceral knowing. This articulation of meaning-making questions what counts as knowing and by extension who and what gets erased when certain forms are privileged. This research links nonhuman theories to the empirical through its inquiry on salt, embodiment, relation, and practice. I develop and utilize intra-views as a multimodal, qualitative approach that engages diffraction not just as a theoretical frame but a mode of praxis. I engage practitioners of different activities involving salt to both learn from their experiences and to include their perceptions and analysis of those stories through a series of different encounters and reencounters with one another and the research materials. This approach entwines data collection with analysis, engaging the participants not as subjects or material to be studied, but as interlocutors while recognizing differences in roles and interests in the process of including multiple viewpoints. Positioning meaning making as an embodied and relational practice engages ethics in relation to knowledge production. I explore this intersection of knowing, values, and practice as an embodied aesthetics, an assertion of ethical obligation relative to power and impact–of responsibility–along with how this interdependence also includes imagination and motivation as points of possibility–articulating the agency that is also present in the complex entanglement of self and others. This is a multiscalar, entangled understanding of responsibility and agency among individual humans, nonhuman entities, and the environment as well as a call to action and respect in our interdependent co-creation of constraints and possibilities in our practices of knowing and world-making. It is both/and rather than either/or as we affect and are affected by one another. An embodied aesthetics embeds ethics within aesthetics to connect knowing to other practices, a development that helps facilitate the entwinement of theory and practice in applied practices such as architecture and design

Linking the effects of helminth infection, diet and the gut microbiota with human whole-blood signatures

Helminth infection and dietary intake can affect the intestinal microbiota, as well as the immune system. Here we analyzed the relationship between fecal microbiota and blood profiles of indigenous Malaysians, referred to locally as Orang Asli, in comparison to urban participants from the capital city of Malaysia, Kuala Lumpur. We found that helminth infections had a larger effect on gut microbial composition than did dietary intake or blood profiles. Trichuris trichiura infection intensity also had the strongest association with blood transcriptional profiles. By characterizing paired longitudinal samples collected before and after deworming treatment, we determined that changes in serum zinc and iron levels among the Orang Asli were driven by changes in helminth infection status, independent of dietary metal intake. Serum zinc and iron levels were associated with changes in the abundance of several microbial taxa. Hence, there is considerable interplay between helminths, micronutrients and the microbiota on the regulation of immune responses in humans

Association of maternal Vitamin D status with glucose tolerance and caesarean section in a multi-ethnic Asian cohort: the growing up in Singapore towards healthy outcomes study

10.1371/journal.pone.0142239PLoS ONE10111-16GUSTO (Growing up towards Healthy Outcomes

Interactions between marine megafauna and plastic pollution in Southeast Asia

Southeast (SE) Asia is a highly biodiverse region, yet it is also estimated to cumulatively contribute a third of the total global marine plastic pollution. This threat is known to have adverse impacts on marine megafauna, however, understanding of its impacts has recently been highlighted as a priority for research in the region. To address this knowledge gap, a structured literature review was conducted for species of cartilaginous fishes, marine mammals, marine reptiles, and seabirds present in SE Asia, collating cases on a global scale to allow for comparison, coupled with a regional expert elicitation to gather additional published and grey literature cases which would have been omitted during the structured literature review. Of the 380 marine megafauna species present in SE Asia, but also studied elsewhere, we found that 9.1 % and 4.5 % of all publications documenting plastic entanglement (n = 55) and ingestion (n = 291) were conducted in SE Asian countries. At the species level, published cases of entanglement from SE Asian countries were available for 10 % or less of species within each taxonomic group. Additionally, published ingestion cases were available primarily for marine mammals and were lacking entirely for seabirds in the region. The regional expert elicitation led to entanglement and ingestion cases from SE Asian countries being documented in 10 and 15 additional species respectively, highlighting the utility of a broader approach to data synthesis. While the scale of the plastic pollution in SE Asia is of particular concern for marine ecosystems, knowledge of its interactions and impacts on marine megafauna lags behind other areas of the world, even after the inclusion of a regional expert elicitation. Additional funding to help collate baseline data are critically needed to inform policy and solutions towards limiting the interactions of marine megafauna and plastic pollution in SE Asia

Recruitment Constraints in Singapore's Fluted Giant Clam (Tridacna squamosa) Populations - A Dispersal Model Approach

10.1371/journal.pone.0058819PLoS ONE83

Robust estimation of bacterial cell count from optical density

Optical density (OD) is widely used to estimate the density of cells in liquid culture, but cannot be compared between instruments without a standardized calibration protocol and is challenging to relate to actual cell count. We address this with an interlaboratory study comparing three simple, low-cost, and highly accessible OD calibration protocols across 244 laboratories, applied to eight strains of constitutive GFP-expressing E. coli. Based on our results, we recommend calibrating OD to estimated cell count using serial dilution of silica microspheres, which produces highly precise calibration (95.5% of residuals <1.2-fold), is easily assessed for quality control, also assesses instrument effective linear range, and can be combined with fluorescence calibration to obtain units of Molecules of Equivalent Fluorescein (MEFL) per cell, allowing direct comparison and data fusion with flow cytometry measurements: in our study, fluorescence per cell measurements showed only a 1.07-fold mean difference between plate reader and flow cytometry data

Common variants in SOX-2 and congenital cataract genes contribute to age-related nuclear cataract

Nuclear cataract is the most common type of age-related cataract and a leading cause of blindness worldwide. Age-related nuclear cataract is heritable (h2 = 0.48), but little is known about specific genetic factors underlying this condition. Here we report findings from the largest to date multi-ethnic meta-analysis of genome-wide association studies (discovery cohort N = 14,151 and replication N = 5299) of the International Cataract Genetics Consortium. We confirmed the known genetic association of CRYAA (rs7278468, P = 2.8 × 10−16) with nuclear cataract and identified five new loci associated with this disease: SOX2-OT (rs9842371, P = 1.7 × 1

Synthesis of zeolitic immidazolate framework membrane

Zeolitic Immidazolate Frameworks (ZIFs) are porous crystalline materials with structures having zeolite framework topologies, where inorganic transition metals such as zinc and cobalt are tetrahedrally coordinated with organic imidazolate links. They are thermally and chemically stable and the organic links offer design flexibility. The high selectivity and capacity for carbon dioxide make ZIFs promising candidates to reduce the amount of carbon dioxide emitted into the atmosphere. Synthesis of ZIF membranes, which was not yet reported in the literature, was explored in this study. ZIF-68, which has the zeolite topology of GME, is synthesized in this study and the synthesis methods, in-situ crystallization and seeded growth method, are adopted from the methodology used in synthesis of zeolite membranes. The membrane obtained by in-situ crystallization is continuous. Moreover, the crystals were randomly oriented and intergrowth between crystals on the porous alumina support can be clearly seen in the SEM images. Extra crystals were found to be adhering onto the walls of the Teflon container. Upon decreasing the concentration of the zinc ions in the solution, the obtained membrane was not continuous. Seeded growth technique was also experimented. The membrane obtained is continuous and thinner. Single-component gas permeation study on the membrane shows that the membrane has the same affinity for different gases due to its large pore size. Further optimization of the conditions and performing the gas separation tests are to be carried out as future works.Bachelor of Engineering (Chemical and Biomolecular Engineering

SINGAPORE'S TRADE IN SERVICES : CHALLENGES AND PROSPECTS

Bachelor'sBACHELOR OF SOCIAL SCIENCES (HONOURS