Most of the bio-applications of semiconductor quantum dots (QDs) show and utilize their superior optical properties over organic fluorophores. An estimated 3-35% of all cancer deaths could be avoided through early detection, therefore, there is a critical need to develop sensitive probes. The objectives of this work are: Research the phenomena of "blue" photoluminescence (PL) spectral shift on the dried bioconjugated QDs and develop the relevant mechanism; Develop a methodology that will allow successful confirmation of the bioconjugation reaction between biomolecules and QDs; Propose a modification of an existent method or approach to employ the "blue" spectral shift of bioconjugated QDs for early cancer detection. Results indicated that the "blue" spectral shift, observed for dried on the silicon substrates bioconjugated QDs, is increased with the time of storage and reaches 30-40nm in 14 days. It is accelerated at elevated temperatures and slowed down at lower temperatures. Larger size QDs generate spectral shifts of larger magnitudes, and the spectral shift is positively correlated with the biomolecule's size/weight. This phenomenon is explained by elastic and compression stress due to nonhomogenious drying of the QD droplet and the reaction with the solid surface. Agarose gel electrophoresis technique, optimized with organic dye fluorescamine, is suitable for bioconjugation verification. The optimal running parameters were found to be 2% agarose gel, 1.5V working voltage, 0.5X TBE as a running buffer, and about 120 mins running time. The spectral shift was implemented for improving the sensitivity of Prostate Specific Antigen (PSA) Enzyme-Linked ImmunoSorbent Assay (ELISA). It was found that QD ELISA could be as much, as 100 times more sensitive than the regular commercial ELISA, based on the enzymatic detection. The results of this work show that QDs may be very useful for early detection of several types of cancers, including prostate cancer in men and breast/ovarian/uterine cancers in women.

京都大学 / 0048 / 新制・課程博士 / 博士(理学) / 甲第18824号 / 理博第4082号 / 新制||理||1587(附属図書館) / 31775 / 京都大学大学院理学研究科化学専攻 / (主査)教授 杉山 弘, 教授 三木 邦夫, 教授 秋山 芳展 / 学位規則第4条第1項該当 / Doctor of Science / Kyoto University / DGAM

The recent technological advances in environmental monitoring coupled with the increasingly stringent effluent requirements being placed on waste treatment systems makes it vital to have a more complete understanding of how specific compounds in waste streams can impact wastewater treatment processes. Since activated sludge processes are recognized as one of the most often applied technologies in wastewater treatment, this study assesses the impacts of select toxic synthetic organic compounds (SOCs) on the activated sludge communities in two types of wastewater treatment reactors: a completely-mixed activated sludge reactor (CMAS) and a sequencing batch reactor (SBR). Commonly applied activated sludge monitoring parameters, such as solids analysis and substrate removal, are collected and correlated to the results of microscopic image analysis (IA) and direct gradient gel electrophoresis (DGGE) to monitor the response of the activated sludge communities to variations in operational conditions, including the incorporation of SOCs in the influent feed and varying the solids retention time. The results of this research indicate that the response of the activated community is highly dependent on the reactor configuration. The CMAS settling performance was more strongly correlated to the shape parameters, and the SBR settling performance was more strongly correlated to the size parameters, which is qualitatively supported by particle settling theory when considering that SBR flocs were found to be larger than the CMAS flocs. The SBR began to exhibit larger floc sizes and had a higher sludge volume index with the incorporation of SOCs, while the CMAS flocs became more spherical after SOCs were incorporated and exhibited more discrete settling. The molecular analysis results revealed that the community structure within the activated sludge system was transient in response to environmental variations. Banding patterns indicated that samples were more similar to other samples taken from the same reactor under the same operational conditions. Thus, as operational conditions were varied, sample banding patterns would also change, indicating transitions in the genetic composition, and ultimately the dominant species present, in response to environmental changes.

京都大学 / 新制・課程博士 / 博士(工学) / 甲第23513号 / 工博第4925号 / 新制||工||1769(附属図書館) / 京都大学大学院工学研究科材料化学専攻 / (主査)教授 大塚 浩二, 教授 松原 誠二郎, 教授 秋吉 一成 / 学位規則第4条第1項該当 / Doctor of Philosophy (Engineering) / Kyoto University / DFAM

Genetic typing of Klebsiella pneumoniae is used for epidemiological referencing. In the clinical setting it can be useful in outbreak investigations, understanding transmission and managing hospital infections. Multi-drug resistant bacteria exist and proliferate either due to natural selection of clonal lineages or the transfer of mobile genetic elements, sometimes in response to antibiotic-use selective pressure. Pulsed-field gel electrophoresis (PFGE) is highly discriminatory and the gold standard typing method for the characterisation of K. pneumoniae isolates. The aim of the study was to genetically characterise K. pneumoniae isolates by PFGE and multilocus sequence typing (MLST). One hundred unrepeated ESBL-producing K. pneumoniae isolates were collected from the National Health Laboratory Service (NHLS). The PFGE was performed on a Rotaphor VI system (Biometra, Germany). Clonal representatives were further characterised by MLST. All the strains were typeable by PFGE using XbaI, which discerned multiple pulsotypes and MLST identified 10 different STs including a novel sequence type, ST1632. The diverse pulsotypes of K. pneumoniae isolates are not suggestive of clonal spread of particular strains. The MLST results further confirmed the variability among isolates tested and elucidated several STs, some of which have been identified internationally and often associated with carbapenem-resistance. Data on K. pneumoniae STs is still limited in the South African clinical setting, although the close monitoring of resistance profiles and characterisation of isolates is imperative for outbreak analysis, identification of prominent STs in clinical settings as compared to international counterparts and surveillance of expanding resistance. / Dissertation (MSc (Medical Microbiology))--University of Pretoria, 2015. / Medical Microbiology / MSc (Medical Microbiology) / Unrestricted

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