Du, Juan. / Thesis (Ph.D.)--Chinese University of Hong Kong, 2011. / Includes bibliographical references (leaves 110-134). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstract also in Chinese.

The UN predicts that by 2050 there will water shortages throughout the globe. Current sources for safe, clean drinking water are being over mined and exhausted. Seawater provides an alternative water source, but a high salt content makes it unsuitable for the majority of applications. However, reverse osmosis lowers the salt content producing water that is safe for human consumption. Reverse osmosis uses a semi-permeable membrane to prevent the transport of salt but allows for the transport of water. Currently these membranes are susceptible to fouling and contamination, which reduces their efficiency. Graphene-oxide membranes offer a new material for reserves osmosis membranes. Sheets of graphene-oxide are stacked in a layered structure. The separation between the sheets can be controlled using physical confinement, resulting in limited ion permeation of abundant cations in seawater, like Na+ and K+. This is believed to be due to the separation of 0.76 nm between the graphene sheets, forcing the ions to lose its surrounding water molecules, making it unfavourable for the ion to travel through the membrane. Molecular dynamics simulations can give an atomic level insight into the molecular processes within GO membranes. Recent simulations have shown that charged species are attracted to graphene surfaces due to polarisation of the pi-electron system. This work has managed to incorporate these ion-pi interactions into molecular dynamics simulations. Including ion-pi interactions caused some ions, like Na+ and K+, to prefer to lose water molecules and reside at a graphene surface. This work observed the same phenomena when ions were confined to graphene channel ranging from 1.3 nm - 0.7 nm. This observation could have a large impact on whether dehydration is limiting the permeation of these two ions, or if there are additional processes that limit their molecular transport.

Yau Ho Yan. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2005. / Includes bibliographical references (leaves 131-144). / Abstracts in English and Chinese. / DECLARATION --- p.I / ACKNOWLEDGEMENTS --- p.II / ENGLISH ABSTRACT --- p.III / CHINESE ABSTRACT --- p.VI / Chapter Chapter 1. --- Introduction --- p.1 / Chapter 1.1 --- Oxidative Stress --- p.1 / Chapter 1.1.1 --- Historical Background of reactive oxygen/nitrogen species --- p.1 / Chapter 1.1.2 --- What is Oxidative Stress? --- p.3 / Chapter 1.1.3 --- Reactive Oxygen Species (ROS) --- p.4 / Chapter 1.1.3.1 --- Superoxide anion (02-) --- p.4 / Chapter 1.1.3.2 --- Hydrogen peroxide (H202) --- p.5 / Chapter 1.1.3.3 --- Hydroxyl radical --- p.6 / Chapter 1.1.3.4 --- Nitric oxide (NO) --- p.7 / Chapter 1.2 --- Cardiovascular System --- p.8 / Chapter 1.2.1 --- Enzymatic and Non-enzymatic Sources of ROS in Cardiovascular System --- p.8 / Chapter 1.2.1.1 --- NADPH oxidase --- p.8 / Chapter 1.2.1.2 --- Hypoxanthine-Xanthine oxidase (HX-XO) --- p.9 / Chapter 1.2.1.3 --- Nitric oxide synthase (NOS) --- p.10 / Chapter 1.2.1.4 --- Mitochondrial electron transport chain (ETC) --- p.11 / Chapter 1.2.1.5 --- Cyclooxygenase --- p.11 / Chapter 1.2.1.6 --- Lipoxygenae --- p.12 / Chapter 1.2.1.7 --- Endoplasmic reticulum --- p.12 / Chapter 1.2.2 --- ROS/RNS Scavenging Systems --- p.13 / Chapter 1.2.2.1 --- Superoxide dismutase (SOD) --- p.13 / Chapter 1.2.2.2 --- Catalase --- p.14 / Chapter 1.2.2.3 --- Glutathione peroxidase --- p.15 / Chapter 1.2.2.4 --- Non-enzymatic antioxidants --- p.15 / Chapter 1.2.3 --- Factors that stimulate ROS production in cardiovascular system --- p.18 / Chapter 1.2.3.1 --- Oxygen tension --- p.18 / Chapter 1.2.3.2 --- "Flow, Shear, and Stretch as an initial stimulus for endothelial oxidant signalling" --- p.18 / Chapter 1.2.3.3 --- Activation of rennin-angiotensin system promote oxidative stress in cardiovascular system --- p.19 / Chapter 1.2.3.4 --- Regulation of vascular ROS production by vasoactive substances --- p.19 / Chapter 1.2.4 --- Regulation of vascular tone in Cardiovascular System by ROS/RNS --- p.20 / Chapter 1.2.4.1 --- Regulation of vascular tone --- p.20 / Chapter 1.2.5 --- Pathophysiological Effects of ROS --- p.23 / Chapter 1.2.5.1 --- Cellular injury by lipid peroxidation --- p.23 / Chapter 1.2.5.2 --- Role of ROS in immune defence --- p.23 / Chapter 1.2.5.3 --- Redox regulation of cell adhesion --- p.24 / Chapter 1.2.6 --- Evidences from Clinical Studies of Oxidative Stress-Related Vascular Diseases --- p.25 / Chapter 1.2.6.1 --- Hyperlipidaemia --- p.25 / Chapter 1.2.6.2 --- Hypertension --- p.25 / Chapter 1.2.6.3 --- Chronic heart failure (CHF) --- p.26 / Chapter 1.2.6.4 --- Chronic renal failure (CRF) --- p.26 / Chapter 1.2.6.5 --- Atherosclerosis --- p.27 / Chapter 1.2.6.6 --- Ischemia/reperfusion (I/R) injury --- p.27 / Chapter 1.2.7 --- Role of Vascular Endothelium in Oxidative Stress --- p.29 / Chapter 1.2.8 --- Role of Ca in oxidative stress in cardiovascular system --- p.29 / Chapter 1.2.8.1 --- Calcium Signaling in Vascular Endothelial Cells --- p.30 / Chapter 1.2.9 --- ROS effect on endothelial Ca2+ --- p.31 / Chapter 1.2.9.1 --- Multiple targets of ROS on intracellular Ca2+ mobilization --- p.32 / Chapter 1.2.9.2 --- Reports of H202-induced Ca2+ release in various cell types --- p.33 / Chapter 1.2.9.3 --- Reported effects of H202 on agonist-induced Ca2+ signal --- p.34 / Chapter 1.2.9.4 --- Differences between macrovessels and microvessels --- p.34 / Chapter 1.3 --- TRP Channel --- p.41 / Chapter 1.3.1 --- Discovery of Drosophila TRP --- p.41 / Chapter 1.3.2 --- Mammalian TRP subfamily --- p.41 / Chapter 1.3.3 --- General topology of TRP channel --- p.42 / Chapter 1.3.4 --- Interactions of oxidative stress with TRP channels --- p.44 / Chapter 1.3.5 --- The role of TRPC3 and TRPC4 in oxidative stress --- p.44 / Chapter 1.3.6 --- TRPM subfamily --- p.44 / Chapter 1.3.6.1 --- Expression of TRPM2 --- p.45 / Chapter 1.3.6.2 --- Dual Role of TRPM´2ؤChannel and Enzyme --- p.45 / Chapter 1.3.6.3 --- Regulatory mechanisms of TRPM2 --- p.46 / Chapter 1.3.6.3.1 --- ADP-ribose (ADPR) directly regulating --- p.46 / Chapter 1.3.6.3.2 --- NAD regulating --- p.46 / Chapter 1.3.6.3.3 --- Oxidative stress regulating independent of ADPR or NAD --- p.47 / Chapter 1.4 --- Cell Death Induced by Oxidative Stress --- p.48 / Chapter 1.4.1 --- Redox status as a factor to determine cell death --- p.48 / Chapter 1.4.2 --- Role of TRPM2 in oxidative stress-induced cell death --- p.48 / Chapter 1.5 --- Aims of the Study --- p.49 / Chapter Chapter 2: --- Materials and Methods --- p.50 / Chapter 2.1 --- Functional Characterization of TRPM2 by Antisense Technique --- p.50 / Chapter 2.1.1 --- Restriction Enzyme Digestion --- p.50 / Chapter 2.1.2 --- Purification of Released Inserts and Cut pcDNA3 Vectors --- p.51 / Chapter 2.1.3 --- "Ligation of TRPM2 Genes into Mammalian Vector, pcDNA3" --- p.52 / Chapter 2.1.4 --- Transformation for the Desired Clones --- p.52 / Chapter 2.1.5 --- Plasmid DNA Preparation for Transfection --- p.53 / Chapter 2.1.6 --- Confirmation of the Clones --- p.53 / Chapter 2.1.6.1 --- Restriction Enzymes Strategy --- p.53 / Chapter 2.1.6.2 --- Polymerase Chain Reaction (PCR) Check --- p.54 / Chapter 2.1.6.3 --- Automated Sequencing --- p.55 / Chapter 2.2 --- Establishing Stable Cell Lines --- p.56 / Chapter 2.2.1 --- Cell Culture --- p.56 / Chapter 2.2.2 --- Geneticin Selection --- p.57 / Chapter 2.3 --- Expression of TRPM2 in Transfected and non-Transfected H5V Cells --- p.57 / Chapter 2.3.1 --- Protein Sample Preparation --- p.57 / Chapter 2.3.2 --- Western Blot Analysis --- p.58 / Chapter 2.3.3 --- Protein Expression Analysis --- p.59 / Chapter 2.4 --- "Immunolocalization of TRPM2 in Human Heart, Cerebral Artery, Renal, Hippocampus and Liver" --- p.59 / Chapter 2.4.1 --- Paraffin Section Preparation --- p.59 / Chapter 2.4.2 --- Immunohistochemistry --- p.60 / Chapter 2.5 --- [Ca2+ ］i Measurement in Confocal Microscopy --- p.62 / Chapter 2.5.1 --- Cytosolic Ca2+ measurement --- p.62 / Chapter 2.5.2 --- Measuring the Ca2+ in the Internal Calcium Stores --- p.63 / Chapter 2.5.3 --- Data Analysis --- p.64 / Chapter 2.6 --- Examining Cell Death Induced by H2O2 by DAPI Staining --- p.65 / Chapter 2.6.1 --- DAPI Staining --- p.65 / Chapter Chapter 3: --- Results --- p.66 / Chapter 3.1 --- Superoxide Anion-Induced [Ca 2+]i rise in H5V Mouse Heart Microvessel Endothelial Cells --- p.66 / Chapter 3.1.1 --- Superoxide Anion-induced [Ca2+ ]i Rise --- p.66 / Chapter 3.1.2 --- Effect of Catalase on the Superoxide Anion-induced [Ca2+]i］］ Rise --- p.66 / Chapter 3.1.3 --- IP3R inhibitor Inhibits Superoxide anion-induced [Ca 2+]i Rise --- p.67 / Chapter 3.1.4 --- Effect of Phospholipase A2 Inhibitor on Superoxide anion- induced [Ca2+]i Rise --- p.67 / Chapter 3.1.5 --- Effect of Hydroxyl Radical Scavenger on Superoxide Anion- induced [Ca2+]i Rise --- p.68 / Chapter 3.2 --- Hydrogen Peroxide-induced Ca2+ Entry in Mouse Heart Microvessel Endothelial Cells --- p.74 / Chapter 3.2.1 --- Hydrogen Peroxide Induces [Ca2 +]i rise in H5V Mouse Heart Microvessel Endothelial Cells --- p.74 / Chapter 3.2.2 --- Hydrogen Peroxide Induces [Ca 2+]i rise in two phases (Rapid and Slow response) --- p.74 / Chapter 3.2.3 --- Hydrogen Peroxide Induces [Ca 2+]i rise in a Extracellular Ca + Concentration Dependent Manner --- p.77 / Chapter 3.3 --- Hydrogen Peroxide Reduces Agonist-induced [Ca2+]i rise --- p.79 / Chapter 3.3.1 --- Hydrogen Peroxide Reduces ATP-induced [Ca2+ ]i rise in a H2O2 Concentration Dependent Manner --- p.79 / Chapter 3.3.2 --- Hydrogen Peroxide Reduces ATP-induced [Ca 2+]i rise in a H2O2 Incubation Time Dependent Manner --- p.79 / Chapter 3.3.3 --- Hydrogen Peroxide Reduces the ATP-induced Intracellular Ca2+ Release --- p.80 / Chapter 3.3.4 --- XeC Inhibited H202-induced [Ca2+]i rise --- p.80 / Chapter 3.3.5 --- Hydrogen Peroxide Partially Depletes Internal Ca2+ Stores --- p.81 / Chapter 3.4 --- Dissecting Signal Transduction Pathways in H202-induced [Ca2+]i rise --- p.82 / Chapter 3.4.1 --- Effect of Phospholipase C Inhibitor on H202-induced [Ca2 +]i rise --- p.82 / Chapter 3.4.2 --- Effect of Phospholipase A2 Inhibitor on H202-induced [Ca 2+]i rise --- p.83 / Chapter 3.4.3 --- Effect of hydroxyl radical scavenger on H2O2-induced [Ca 2+]i rise --- p.83 / Chapter 3.5 --- Functional Role of TRPM2 Channel in H202-induced [Ca2+]i Rise in H5V Cells --- p.92 / Chapter 3.5.1 --- Expression of TRPM2 and the Effect of TRPM2 Antisense Construct on TRPM2 Protein Expression --- p.92 / Chapter 3.5.2 --- Effect of Antisense TRPM2 on H202-induced Ca2+ Entry --- p.94 / Chapter 3.6 --- H202-induced Cell Death --- p.101 / Chapter 3.7 --- Expression Pattern of TRPM2 Channel in Vascular System --- p.104 / Chapter 3.7.1 --- Immunolocalization of TRPM2 in Human Cerebral Arteries --- p.104 / Chapter 3.7.2 --- Immunolocalization of TRPM2 in Human Cardiac Muscles --- p.105 / Chapter 3.7.3 --- Immunolocalization of TRPM2 in Human Kidney --- p.105 / Chapter Chapter 4: --- Discussion --- p.113 / Chapter 4.1 --- Oxidative modification of Ca2+ homeostasis --- p.113 / Chapter 4.2 --- Pathophysiological effects of ROS on endothelium --- p.113 / Chapter 4.3 --- Effects of ROS on microvascular endothelial Ca2+ reported by other investigators --- p.115 / Chapter 4.4 --- Studies of the effect of HX-XO on cytosolic [Ca2+]i --- p.116 / Chapter 4.4.1 --- Role of 0´2Ø- and H202 in HX-XO-induced [Ca2+]i elevation --- p.116 / Chapter 4.4.2 --- IP3R involvement in HX-XO-evoked Ca + movements in H5V cells --- p.118 / Chapter 4.4.3 --- PLA2 involvement in HX-XO experiment --- p.119 / Chapter 4.5 --- Studies of the effect of direct H202 application on cytosolic [Ca2+]i --- p.120 / Chapter 4.5.1 --- Hydrogen Peroxide Induced [Ca2 +]i rise in a Extracellular Ca2 + Concentration Dependent Manner --- p.120 / Chapter 4.5.2 --- Hydrogen Peroxide Induced [Ca 2+]i rise in two phases (Rapid and Slow response) --- p.121 / Chapter 4.6 --- Effect of H202 on ATP-induced Ca2+ response --- p.121 / Chapter 4.6.1 --- H202 inhibited ATP-induced Ca2+ release in a concentration and time dependent manner --- p.121 / Chapter 4.6.2 --- IP3R involvement and store depletion in H202 experiment --- p.123 / Chapter 4.7 --- Dissecting Signal Transduction Pathways in H202-induced [Ca2+]i rise --- p.124 / Chapter 4.7.1 --- PLC involvement in H2O2 experiment --- p.124 / Chapter 4.7.2 --- PLA2 involvement in H2O2 experiment --- p.125 / Chapter 4.7.3 --- Hydroxyl radical did not involve in H2O2 experiment --- p.125 / Chapter 4.8 --- Functional Studies of TRPM2 --- p.127 / Chapter 4.8.1 --- Expression of TRPM2 in H5V on protein level --- p.127 / Chapter 4.8.2 --- TRPM2 involvement in the Ca2+ signalling in response to H2O2 in H5V cells --- p.127 / Chapter 4.9 --- H202 concentration in my projec´tؤphysiological or pathological? --- p.128 / Chapter 4.10. --- H20´2ؤTRPM´2ؤCell death --- p.129 / Chapter 4.11 --- Expression of TRPM2 in human blood vessels and other tissues --- p.130 / References --- p.131

Kwan Hiu Yee. / "June 2006." / 2+ in the title is superscript. / Thesis (Ph.D.)--Chinese University of Hong Kong, 2006. / Includes bibliographical references (p. 131-150). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstracts in English and Chinese.

Mesoporous silica gel containing embedded phosphotungstic acid (PTA) was synthesized by sol-gel co-condensation of tetraethyl orthosilicate with PTA in acidic media. The obtained material had high Brunauer-Emmett-Teller Theory (BET) surface area and pore volume. A characteristic band of the Keggin structure of PTA was present in its FT-IR spectrum while its X-ray diffraction patterns were absent. This proved the embedding of PTA on a sub-molecular level and not as a second phase. Acidic sites were determined by neutralization with base in aprotic solvent, followed by titration of the remaining base with an acid. The material demonstrated high adsorption capacity of Cs. Kinetic studies showed that the adsorption data correlates strongly with the pseudo-second order model. At higher temperatures, the nature of adsorption fit the Langmuir model extremely well. The obtained results can be used in the development of an effective adsorbent for clean-up of water contaminated by radioactive 137Cs.

Guanine is generally accepted as the most easily oxidized DNA base when cells are subjected to ionizing radiation, photoionization or photosensitization. At pH 7, the midpoint reduction potential is on the order of 0.2 – 0.3 V higher than those of the radicals of e.g. tyrosine, tryptophan cysteine and histidine, so that the radical “repair” (or at least, a thermodynamically favorable reaction) involving these amino acids is feasible. Computational quantum studies have been done on tyrosine, tryptophan, cysteine and histidine side chains as they appear in histones. Density functional theory was employed using B3LYP/6-31G+ (d, p) basis set to study spin densities on these amino acids side chains as they pair with the guanine radical cation. The amino acid side chains are positioned so as not to disrupt the Watson-Crick base pairing. Our results indicate that, these side chains of amino acid with reducing properties can repair guanine radical cation through electron transfer coupled with proton transfer.

Engineered organoclays are 2:1 phyllosilicate soils that have been synthesized with a controlled interlayer organic phase to exhibit enhanced strength, lower compressibility, and stronger retention of organic compounds. Engineered organoclays are highly sorptive, and have a variety of potential engineering applications as sorbents or amendments in engineered earthen barrier systems. Previous studies examined the impact of the organic coating on a soil's physical properties; however, the geochemical behaviors of organoclays, especially their interaction with organic compounds at the micro-scale, remained relatively unquantified. This study investigated the engineering behavior of montmorillonite modified with a variety of quaternary ammonium cations (QAC clays) with controlled structure and density of loading. Molecular dynamics simulations were used to model the surfactant arrangement, geochemical processes in the QAC-clay interlayer, including organic compound sorption and mass transport, as well as the surface electrokinetics of suspended QAC-clay particles. All simulations were carried out based on the combined force field of ClayFF and the Consistent-Valence Force Field to ensure the accuracy of the simulation results, and results yielded insight into the prediction of synthesized QAC-clay behaviors as sorptive material for non-polar organic compounds.

LOW TEMPERATURE SYNTHESIS AND CHARACTERIZATION OF SOME LOW POSITIVE AND NEGATIVE THERMAL EXPANSION MATERIALS Kathleen Madara White 151 pages Directed by Dr. Angus P. Wilkinson Low temperature non-hydrolytic sol-gel synthesis was used to explore the possibility of lowering the crystallization temperatures of some known AIVMV2O7 compounds. Crystallization temperatures for ZrP2O7 and ZrP2O7 were unaffected by the use of non-hydrolytic sol-gel methods; however, successful synthesis of these compounds broadens the range of materials that can be produced using this method and suggests the possibility of synthesizing solid solutions (or composites) including ZrP2O7 or ZrV2O7. This research presents for the first time the direct synthesis of ZrP2O7 from separate zirconium and phosphorus starting materials using mild autoclave methods. Characterization of some AIVMV2O7 compounds, using lab and high resolution synchrotron powder XRD, led to the assignment of a new symmetry for CeP2O7 and to the suggestion that the reported structure for PbP2O7 was inadequate. Studies using in situ high temperature lab and synchrotron powder XRD for PbP2O7 and CeP2O7 provided the opportunity to report their thermal properties for the first time, and to compare their behavior to that of some other AIVMV2O7. High pressure diffraction measurements on CeP2O7 provided data for the estimation of bulk moduli and suggested two possible pressure-induced phase transitions. A broad range of MIIIMVP4O14 compounds were prepared using low temperature hydrolytic sol-gel synthesis. Thermal studies revealed nearly linear trends in CTEs and lattice constants with respect to the sizes of MIIIMV cations. Some lower ionic radii compounds had CTEs comparable to that of ZrP2O7 at low temperature, suggesting a similar superstructure. Three compounds were found to exhibit temperature-induced phase transitions.

Long-distance radical cation transport was studied in DNA condensates where linearized pUC19 plasmid was ligated to an oligomer and transformed into DNA condensates with spermidine. DNA condensates were detected by Dynamic Light Scattering and observed by Transmission Electron Microscopy. Introduction of charge into the condensates causes long-distance charge migration, which is detected by reaction at the remote guanines. The efficiency of charge migration in the condensate is significantly less than it is for the corresponding oligomer in solution. This result is attributed to a lower mobility for the migrating radical cation in the condensate, caused by inhibited formation of charge-transfer-effective states. Radical cation transport was also studied in DNA condensates made from an oligomer sandwiched between two linearized plasmids by double ligation. Unlike the single ligated plasmid condensates, the efficiency of charge migration in the double ligated plasmid-condensates is high, indicative of local structural and conformational transformation of the DNA duplexes. Organic monomer units having extended ð-conjugation as part of a long conducting polymer was synthesized and characterized. The monomer units were covalently attached to particular positions in DNA oligonucleotides by either the convertible nucleotide approach or by phosphoramidite chemistry. Successful attachment of the monomer units to DNA were confirmed by mass spectral analysis. The DNA-conjoined monomer units can self assemble in the presence of complementary sequences which act as templates that can control polymer formation and structure. By this method the para-direction of the polymer formation can be enforced and may be used to generate materials having nonrecurring, irregular structures.

Ensemble learning is a multiple-classi&amp / #64257 / er machine learning approach which combines, produces collections and ensembles statistical classi&amp / #64257 / ers to build up more accurate classi&amp / #64257 / er than the individual classi&amp / #64257 / ers. Bagging, boosting and voting methods are the basic examples of ensemble learning. In this thesis, a novel boosting technique targeting to solve partial problems of AdaBoost, a well-known boosting algorithm, is proposed. The proposed systems &amp / #64257 / nd an elegant way of boosting a bunch of classi&amp / #64257 / ers successively to form a better classi&amp / #64257 / er than each ensembled classi&amp / #64257 / er. AdaBoost algorithm employs a greedy search over hypothesis space to &amp / #64257 / nd a good suboptimal solution. On the other hand, this work proposes an evolutionary search with genetic algorithms instead of greedy search. Empirical results show that classi&amp / #64257 / cation with boosted evolutionary computing outperforms AdaBoost in equivalent experimental environments.