Mucopolysaccharidosis IIIB (MPS IIIB) is an autosomal recessive disorder of glycosaminoglycan (GAG) metabolism. Disruption of the gene encoding a-N-acetylglucosaminidase (Naglu) results in the inability to degrade the GAG heparan sulfate (HS). Consequently. undegraded HS builds up and results in the secondary accumulation of gangliosides and substantial changes in the expression of genes related to neural cell growth and function. Clinically, affected individuals display hyperactivity. insomnia and severe and progressive mental retardation. Currently. no treatment or cure is available for this devastating disorder which is ultimately fatal. Enzyme replacement therapy is one method being examined as an avenue for treatment of MPS IIIB. but it has yet to overcome difficult obstacles, such as production and targeted delivery. This thesis examines the use of the methylotrophic yeast Pichia pastoris as a host for the production of recombinant Naglu. A protein transduction domain (PTD) derived from the HIV-l Tat protein was fused to Naglu to circumvent the current problems faced in delivering this therapeutic enzyme. Expression of this fusion protein was tested in four different strains of Pichia. each with unique attributes. Though the Naglu produced was in an active recombinant form. it was not abundant and this has precluded further characterization. It is likely that inefficiency at the transcriptional/post-transcriptional level hindered higher expression levels. Optimization of these factors may well facilitate Naglu expression in Pichia pastoris. and ultimately allow for substantial enzyme production for use in replacement therapy.

In this thesis, a novel method of imaging the near-field intensity patterns of a vertical-cavity surface-emitting laser (VCSEL) is presented. The method is to use an imaging spectrometer to separate closely spaced modes and to image a vertical slice of each profile. The images are then reconstructed to form a composite image. Based on the near-field image, the refractive index profile of the VCSEL is extracted. The method to extract the refractive index profile is based on a method derived from Maxwell's Equations and the Poynting Vector. The results of both the mode images and the refractive index profile are found to be in agreement with those obtained elsewhere.

Piezoelectric and electrostrictive actuators composed of lead titanate zirconate (PZT) and lead magnesium niobate-lead titanate (PMN-PT) are important in a variety of engineering applications. A review of the literature indicated that published phase diagrams for the PMN-PT system are based primarily on temperatures of dielectric transitions. rather than direct measurements of structural changes. Structural transformations in the PMN-PT ceramic system have not been investigated at non-ambient temperatures for compositions with less than 0.29 PT. The review also revealed that crack growth in cyclic electric fields has been observed in only two compositions of PZT, while no crack initiation or growth is observed in a relaxor composition of PMN-PT. The X-ray diffraction results showed that the PMN-PT samples undergo multiple structural transformations on cooling through the temperature regions of their dielectric transitions. In compositions containing 0.0, 0.08, 0.10 and 0.20, an upper transformation temperature Ta, derived from a sharp change in coefficient of thermal expansion, lies well above the temperature Tm, of the observed maximum in dielectric constant. Lower structural transformation temperatures observed in these c compositions lie close to the freezing temperature Tf, below which ceramics exhibit remanent polarization. The temperatures of an upper structural transformation in PMN-PT ceramics with the higher PT mole fractions 0.30 and 0.35, agree closely with the Curie Temperature Tc. Cracks emanating from the corners of Vickers diamond indents in the soft piezoelectric ceramics BM532 PZT (Navy-Type VI) and PMN-0.30PT were increased in length when subjected to low frequency cyclic electric fields that were applied normal to the crack. Crack growth was observed in fields of 2-5 x Ec, but no new cracks were initiated when these higher fields were applied. Similar induced cracks in hard piezoelectric PZT ceramics, did not exhibit visible crack growth when subjected to low frequency fields with amplitudes up to +3.15 MV/m (1.6 x Ec), which is considered to be a safe maximum to avoid dielectric breakdown in PZT ceramics. No cracks were observed to emanate from the corners of either Vickers, or Knoop, diamond indents in samples of PMN-0.08PT. The intergranular cracks which emanate from the sides of the indents did not grow, and no new cracks were initiated, when the specimens were subjected to similar electric fields.

The activity of plant estrogens, genistein (GEN) and enterolactone (ENL), on mammalian cells is not well understood. Previously, they have been shown to exhibit a biphasic effect, being stimulatory at low doses and inhibitory at high doses. Therefore, consumption of plant estrogens by women with breast cancer has become controversial. Simplified flow cytometry applications to quantify the degree of proliferation and apoptosis were used to measure differentiation and growth inhibitory properties of GEN and/or ENL on two estrogen receptor-positive, MCF-7 and T47D, and two estrogen receptor-negative, MDA-MB-231 and MDA-MB-468, breast cancer cell lines in the presence and absence of I7β-estradiol (E2). Activity in the presence of 4-hydroxytamoxifen (OHT) was also evaluated. A live cell assay using propidium iodide (PI) and fluorescein diacetate was used for evaluation of live, apoptotic and necrotic populations. The biological activity of ENL and GEN in tissue culture was confirmed by MTT assay. An Annexin V/PI live cell assay confirmed the presence and degree of apoptosis. No effect was seen at lower doses, ie. less than 10µM and 5011M in estrogen receptor-positive, ER (+), cells and decreased viability was seen at ENL 10 µM in one estrogen receptor-negative, ER (-), cell line. A significant reduction in viability was seen with treatments of 100 µM of ENL and GEN in both ER (+) cell lines. The effect of combining E2 with treatments of GEN 50 and 100 µM was a reduction in viability in one ER (+) cell line. The effect of combining treatments of low doses of ENL and GEN (10 MM) resulted in a reduction in viability in one ER (+) and one ER (-) cell line. Treatment of ER (+) breast cancer cell lines with low dose GEN (10 µM) and high dose ENL and GEN (50 MM) combined with low dose OHT (10 µM ) reduced viability in excess OHT 10 µM alone. High dose OHT (50 µM ) significantly reduced viability in all cell lines. However, when high dose OHT was combined with low dose ENL and GEN, there was an effect of rescuing ER (-) cells from OHT-induced apoptosis and necrosis. Although the use of high dose OHT is not typically used to treat ER (-) breast cancer, these results suggest the action of plant estrogens is more varied than previously thought. This work supports the notion that there may be dissimilarity in the actions between ENL and GEN which may warrant separate recommendations regarding dietary consumption, especially in women with breast cancer.

This study examines the meaning of environmental involvement for early adolescents based on research with children from around the world. It arises from an interest in understanding the role children play in bringing about change in society given the increase interest in children's rights. Literature on environmental education pointed to action as a focus of analysis for researching the activities of "environmentally-involved" children. In gathering the study data, agency emerged as a more appropriate organizing concept given the depth and contextual nature of children's environmental involvement. Agency places the emphasis on defining how children interact with the various structures that affect their lives. Through the lens of agency, light is shed on children's creativity and pragmatism, with children's actions, critical thinking and imagination being of equal importance. The ability of children to maneuver through significant life experiences, beliefs towards nature, and age-defined barriers stands out. The study also shows how the unfolding of agency is intimately linked to learning and identity-building in early adolescence. Environmental involvement becomes a medium for children to explore and define themselves in relation to others, including the social and physical environment, as they transition from childhood to adulthood. The 2002 International Children's Environment Conference held in Victoria, Canada, which brought together 400 environmentally involved 10-to-12 year olds from 66 countries, provided the site for the research. Diverse methods served to explore the research questions: 42 open-ended interviews, using both literal and metaphorical questions, mind-mapping activities. 116 visual surveys, and field notes. Elements of grounded theory and narrative inquiry were used to analyze and present the data. The shape of a rainbow served as a unifying metaphor to present the environmental agency model. Although the children came from different parts of the globe, I identified a collective view of the world -- attributed to their shared development process and a favourable international agenda. Six dimensions of agency are identified. In connectedness, children relate to nature as well as to other people. It deals with the sense of wonder, often evoked in descriptions of special place. In engaging with the environment, children integrate and process the knowledge gained from direct or indirect contact with nature. In questioning, children respond to the world awakening to its contradictions and complexities. In belief in capacity, children see themselves as affecting change and are hopeful for the planet's future. In taking a stance, children overcome the lack of adult and peer support. Then comes strategic action, where children select an approach to addressing environmental problems. The shape of the rainbow arc and blending of its bands reflect the interlinkages between all the dimensions. Annotated vignettes bring to life how the six dimensions of environmental agency play out in the life of each child. Although they unfold differently, the dimensions have relevance to each environmental story. Four profiles of involvement have been recognized: initiator, creative, member, and grounded. The typology represents the variety and complexity in children's environmental activism. There is a need to value the range of environmental experiences children engage in, of the role of process and the subtleties involved in building relationships with nature and society. Adults need to partner with children multiplying the opportunities for children to express their agency. As warriors of the rainbow, children's most intriguing contribution may lie in the way that they convey to others, with frankness and lucidity, their concern for the environment, our planet.

The application of digital signal processing (DSP) for the identification of the locations of hot spots in proteins is explored. DSP provides a natural framework for analyzing biologi¬cal sequence information due to the inherently discrete nature of the biological sequences. Two new techniques for the identification of the locations of hot spots in proteins are proposed. In the first technique. the short-time discrete Fourier transform (STDFT) of the protein numerical sequence is computed and its columns are multiplied by the discrete Fourier transform (DFT) coefficients. Through this technique, hot-spot locations can be clearly identified in teens of distinct peaks in the spectrogram, thus achieving good local¬ization in the amino-acid domain. Several example protein sequences are used to illustrate the technique. The second technique is based on the use of digital filters. The criteria that determine the filter type and the filter-design specifications for the application of interest are dis¬cussed. Based on this investigation, the inverse-Chebyshev UR digital filter is found to be the most suitable filter for the application. The use of zero-phase filtering to eliminate the need of computing the phase response of the digital filter is also investigated. A control parameter that can be used to distinguish the hot-spot locations on the basis of their sig¬nificance in the protein's function is introduced. The technique is then illustrated by using the same set of example protein sequences that were used for the first technique. The two techniques are then compared in teens of their computational complexity. The filter-based technique is found to be computationally much more efficient than the transform-based technique and hence it is much more suitable for a hardware implementation. The proposed techniques are capable of identifying the known hot-spot locations with good accuracy. In addition, they also identify several new hot-spot locations that may provide new insights into the working of protein molecules.

The cationic antimicrobial peptides, indolicidins and polyphemusins, have shown activity against animal pathogenic viruses. The aim of this work was to evaluate the efficacy of these peptides for engineering plants with a broad-spectrum disease resistance, including viral diseases. TTC, Evan's blue and phytotoxicity assays showed low cytotoxicity of indolicidin and polyphemusin variants (10R, 11R and PV5) on tobacco leaf discs, protoplasts and plantlets. In vitro assays using these variants showed a broad-spectrum activity against plant pathogenic bacteria, fungi and viruses. An assessment of in planta activity was performed by expressing these cationic peptides in transgenic tobacco (Nicotiana tabacum var Xanthi). The disease assays using detached leaves from transgenic tobacco plants showed a broad-spectrum disease resistance against bacteria, fungi and 'TMV. Further work is needed on optimization of expression of these peptides and their combinations for successful application of this approach under greenhouse and field conditions.

Numerous techniques have been used to characterize ultraviolet polarization sensitivity (PS) in teleost fishes. To date PS in the rainbow trout (Oncorhynchus mykiss) has been characterized using compound action potential (CAP) recordings from the optic nerve. CAP recordings have also been used in conjunction with chromatic adaptation to isolate the individual cone photoreceptor mechanisms responsible for PS detection. The primary goal of this thesis was to discover the ancestry of PS within the Salmoninae clade containing Salmo, Salvelinus and Oncorhynchus, by characterizing and mapping the cone photoreceptor mechanisms mediating PS onto the phylogeny. I developed a research paradigm that used electroretinogram (ERG) recordings to characterize PS in rainbow trout. Substantial differences were found between CAP and ERG recordings. When identical stimuli were used, ERG recordings produced two additional peaks of maximal sensitivity at 45° and 135°. Chromatic adaptation was used to explore differences in bipolar cell and optic nerve generated PS curves. Under chromatic adaptation, with the use of ERG recordings, the additional peaks shifted consistently with the adaptation of either the horizontal or vertical polarization detector mechanism. These findings have contributed to the understanding of how ultraviolet polarized light is processed within the visual system I then used CAP and ERG recordings to characterize PS in Atlantic salmon (Salmo salar), because of its basal relationship within the Salmo, Salvelinus and Oncorhynchus clade. PS results obtained from CAP and ERG recordings were similar for Atlantic salmon and rainbow trout. CAP recordings generated a `W'-shaped PS curve maximally sensitive at 0°, 90°, and 180°, while ERG recordings generated a tuning curve with the additional peaks of maximal sensitivity at 0°, 45°, 90°, 135° and 180°. Therefore, it was concluded that both PS and the mechanisms of retinal processing underlying it are ancestral within the clade making up Salmo, Salvelinus and Oncorhychus. This has implications for the sensory abilities available when diadromous life histories evolved in Salmonidae.

A sample of 55 female and 41 male university students (N = 96) enrolled in introductory psychology courses participated in a 2 by 2 (uncertainty by communication) factorial between-subjects ANCOVA design investigating the independent and joint effects of uncertainty and communication on cooperation rates in a simulated commons dilemma. Participants' self-efficacy and risk perceptions (pertaining to resource management) were also examined as covariates to investigate each of their relations to cooperation rates. Participants were randomly divided into groups of three and "fished" in a computer simulation of ocean fishing (FISH 3.1), and completed a short questionnaire. As predicted, the presence of group communication was associated with higher rates of cooperation; the presence of uncertainty was associated with lower cooperation rates; and higher levels of resource management self-efficacy were associated with higher cooperation rates. The prediction that the detrimental effect of uncertainty would be more pronounced when there is no communication present received partial support: a marginally significant interaction was found between communication and uncertainty. Contrary to expectations, higher levels of resource management risk perception were associated with lower cooperation rates. Limitations of the current investigation are outlined and possible directions for future research are discussed.

A new multi-step self-assembly route to polymer-semiconducting nanoparticle photonic structures is described. The multi-step self-assembly strategy targets complex hierarchical structures in which organization of cadmium sulfide (CdS) nanoparticles on progressively longer length scales is introduced via a series of three self-assembly steps. each involving building blocks of increasing structural complexity. Each self assembly step can be described as follows: 1) SA1: self-assembly of PS-b-PAA to form block ionomer reverse micelles, followed by synthesis of a single CdS semiconducting nanoparticle in each core, forming the hybrid building blocks PS-CdS: 2) SA2: self-assembly of blends of PS-CdS and PS-b-PAA stabilizing chains in DMF/water mixtures by addition of water to form spherical nanoparticle assemblies, termed large compound micelles (LCMs); 3) SA3: self-assembly of LCMs into ordered close packed arrays by slow water evaporation. The kinetic freezing of building blocks at each stage offers the potential for unique control of nanoparticle self-assembly step since each step is "locked in", allowing structural features determined by the subsequent step to be independently tuned through a new set of experimental variables. Chapter 2 and 3 of this thesis investigate aspects of size and polydispersity control of spherical nanoparticle assemblies in the SA2 self-assembly step. Chapter 4 demonstrates that LCMs can be further assembled (SA3 step) to form three-dimensional hierarchical arrays.