Published Article / The vision of CUT is to transform itself into a sustainable university, by incorporating sustainable development in its teaching, research and learning environment, and by maximizing and mainstreaming environmental, economic and social sustainability in all its operations and educational activities. For this reason it launched a sustainable development (SD) project in February 2011. This process is being managed by the Office of Technology and Innovation and executed according to a project plan, which is continually rolled-out as progress is being made with the project. This article is a brief summary of progress that has been made during the first year of implementation of the plan.

Biodegradable, pH-responsive hydrogel networks composed of poly(methacrylic acid) crosslinked with varying mol percentages of polycaprolactone diacrylate were synthesized. These materials were characterized using NMR and FTIR. The equilibrium and dynamic swelling properties of these pH-responsive materials were studied. Also, the materials’ degradation was characterized using swelling studies and gel permeation chromatography. Methods were developed to incorporate these novel hydrogels as sensing components in silicon-based microsensors. Extremely thin layers of hydrogels were prepared by photopolymerizion atop silicon microcantilever arrays that served to transduce the pH-responsive volume change of the material into an optical signal. Organosilane chemistry allowed covalent adhesion of the hydrogel to the silicon beam. As the hydrogel swelled, the stress generated at the surface between the hydrogel and the silicon caused a beam deflection downward. The resulting sensor demonstrated a maximum sensitivity of 1nm/4.5E-5 pH unit. Sensors were tested in protein-rich solutions to mimic biological conditions and found to retain their high sensitivity. The existing theory was evaluated and developed to predict deflection of these composite cantilever beams. Another type of hydrogel-based microsensor was fabricated utilizing porous silicon rugate filters as transducers. Porous silicon rugate filters are garnering increased attention as components of in vivo biosensors due to their ability for remote readout through tissue. Here, the biodegradable, pH-responsive hydrogel was polymerized within the pores of a porous silicon rugate filter to generate a novel, completely degradable sensor. Silicon was electrochemically etched in hydrofluoric acid to generate the porous silicon rugate filter with its reflectance peak in the near infrared region. Poly(methacrylic acid) crosslinked with polycaprolactone diacrylate was polymerized within the pores using UV free radical photopolymerization. The reflectance peak of this sensor varied linearly with pH in the region pH 2.2 to 8.8. This work shows promise towards utilizing porous silicon rugate filters as transducers for environmentally responsive hydrogels for biosensing applications. / text

The advent of highly sophisticated drugs designed to interfere with specific cellular functions has created the demand for “intelligent” carriers that can efficiently deliver therapeutic agents in response to a pathophysiogical condition. Nanoscale intelligent systems can maximize the efficacy of therapeutic treatments in numerous ways because they have the ability to rapidly detect and response to disease states directly at the site and sparing physiologically healthy cells and tissues, thereby improving a patient’s quality of life. Nanoparticle fabrication has primarily relied on emulsions, self-assembly and micelles based methods which inherently generate polydisperse spherical particles with little control over particle geometry. Despite significant progress in such drug delivery systems, critical limitations remain in synthesizing nanocarriers with highly controllable architecture (size, shape or aspect ratio) that can, at the same time, impart response-sensitive release mechanisms. These parameters are essential for controlling the in-vivo transport, bio-distribution, and drug release mechanisms. The objective of my dissertation is to employ the nanofabrication technique Step and Flash Imprint Lithography (S-FIL) to synthesize stimuli-responsive nanocarriers of precise architectures and composition. Applying S-FIL technology, fabrication of nanocarriers of a variety of shapes and sizes (down to 36nm length scale) that are also environmentally responsive by incorporating enzymatically-degradable peptides into the nanocarrier hydrogel matrix, to provide triggered release of encapsulated therapeutic agents in response to specific pathophysiological conditions, has been accomplished. Besides disease-responsive release, the two key properties of an effective nanocarrier are (a) efficient targeting to specific tissues and cells and (b) avoiding rapid clearance and remaining in circulation in the blood stream for a significant amount of time to increase particle uptake in target tissues. These two properties are expected to be dependent on the shape and size of the carriers. Using various shape and size S-FIL fabricated nanoparticles, the effects of particle geometry on intracellular uptake has also been evaluated. In this dissertation, I will present the extensive work that has been done in the fabrication and optimization of the S-FIL nanocarriers, evaluation of the nanocarrier’s in vitro properties, and evaluation of the effects of nanocarrier geometry on intracellular uptake. / text

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The integration of windcatchers in the urban context of hot-arid context of Tehran needs to address two changes in the current utilization: 1) high density context which makes it harder to access to sufficient airflow in the urban context, and 2) sociocultural shifts towards dependencies on modern mechanical air-conditioning systems. Windcatchers are unique tools existing in the hot-arid regions in the Middle East. Windcatcher uses thermal mass, evaporation techniques, and stack effect to deliver human comfort to the residents of the building. Vernacular windcatchers are useful for moderating the indoor air temperature. Yet, using natural ventilation techniques as passive strategies are outdated in recent decades and there are a couple of reasons for that such as maintenance difficulties, lack of urban air filtration methods, decline of cooling efficiency due to modified airflow patterns, habitable space utilization modifications, and dependencies on mechanical cooling systems. On the other hand, tensile structures have the potential to be considered as a tool to upgrade the windcatchers and use them in the modern urban context which will also help reducing energy and reviving local textile industry. This research tries to propose a method that emphasizes on the adaptability of windcatchers and tensile structures, inhabitant control, airflow control and reuse of heavy thermal mass. Also, the proposed model offers improvements for environmental performance of lightweight textiles, such as particulate matter filtration, kinetic energy transformation, and photoresponse for passive shading or natural daylighting strategies. The main goal of this research is to define the parameters required to enhance inhabitant adaptability with the windcatcher and also natural ventilation cooling system. In this research, important characteristics of Sangelaj neighborhood in Tehran are considered such as existing windcatcher dimensions, micro-climate conditions, and urban morphology. Then, different methods are proposed to develop the heat transfer and airflow analysis of the integration between windcatchers and tensile structures. The research suggests methods for adaptation of windcatchers in existing buildings of Tehran using tensile structures. It also proposes methods for the new buildings in the urban context of Sangelaj neighborhood in Tehran.

The objective of this thesis is to investigate well-defined cross-linked particles synthesized via the reversible addition fragmentation chain transfer (RAFT) process that can be used for drug delivery. To achieve this aim, a wide range of cross-linked micelle systems have been synthesized and intensively investigated. Various biocompatible monomers were employed, including poly (ethylene glycol) methyl ether methacrylate, 2-hydroxyl ethyl acrylate, functionalized glucosamine and nucleotides containing monomers. Different cross-linked structures were used, for example, core-cross-linked, nexus-cross-linked and shell-cross-linked micelles. Diverse stimuli-responsive particles were used, such as pH-sensitive, thermo-sensitive and thiol-sensitive cross-linked systems. Evidences of the successful synthesis of all the resulting cross-linked products are given. They displayed better properties, as drug carriers, than non-cross-linked micelles. A thermo-responsive seven-arm star glycopolymer, synthesized via the RAFT process, was also investigated.

This dissertation presents the synthesis of stimuli-sensitive hydrophilic polymers, particularly doubly responsive hydrophilic block copolymers, by controlled radical polymerizations and the study of their solution behavior in water. By incorporating a small amount of stimuli-responsive groups into the thermosensitive block of a hydrophilic block copolymer, the lower critical solution temperature (LCST) of the thermosensitive block can be tuned by a stimulus and multiple micellization/dissociation transitions can be achieved by combining two external triggers. Chapter 1 describes the synthesis and thermosensitive properties of two new watersoluble polystyrenics with a short oligo(ethyl glycol) pendant from each repeat unit and the study of hydrophobic end group effects on cloud points of thermosensitive polystyrenics. Well-defined polymers were prepared from monomer-based initiators via nitroxide-mediated polymerization and the alkoxyamine end groups were removed by tri(n-butyl)tin hydride, yielding thermoresponsive polystyrenics with essentially no end groups. The results showed that hydrophobic end groups could significantly change the cloud points and the molecular weight dependences of cloud points of polystyrenics. Chapter 2 presents the synthesis of thermo- and light-sensitive hydrophilic block copolymers, poly(ethylene oxide)-b-poly(ethoxytri(ethylene glycol) acrylate-co-onitrobenzyl acrylate), and their responsive behavior in dilute aqueous solutions. Dynamic light scattering and fluorescence spectroscopy studies showed that these copolymers were molecularly dissolved in water at lower temperatures and self-assembled into micelles at temperatures above the LCST of the thermosensitive block. Upon UV irradiation, the oiv nitrobenzyl group was cleaved and the LCST of the thermosensitive block was increased, causing the dissociation of micelles into unimers. The resultant copolymers underwent thermo-induced reversible micellization at higher temperatures. Chapter 3 describes multiple micellization/dissociation transitions of thermo- and pH-sensitive hydrophilic block copolymers, poly(ethylene oxide)-b-poly(methoxydi(ethylene glycol) methacrylate-co-methacrylic acid), in response to temperature and pH changes. The LCST of the thermosensitive block can be reversibly tuned and precisely controlled by solution pH. Chapter 4 presents the study on multiple sol-gel-sol transitions of a 20.0 wt % aqueous solution of poly(ethylene oxide)-b-poly(ethoxytri(ethylene glycol) acrylate-co-o-nitrobenzyl acrylate) induced by temperature changes and UV irradiation. The solution underwent thermo-induced sol-gel-sol transitions. Upon UV irradiation to dissociate micelles, the gel was transformed into a free-flowing liquid, which upon heating underwent sol-gel-sol transitions again.

This qualitative study examined the dropout crises from the perspectives of Mexican American dropouts labeled as learner disabled who were receiving special education services. Such study is imperative as this group increases both in school and in special education classes. There were two research questions that guided the study: 1. What are the perceptions of Mexican American dropouts who participated in a special education program regarding their educational experiences? 2. What were the factors that influenced these students’ decisions to drop out of school? From the participant interviews, historical academic documents, and rich-descriptive information gathered from the students’ voices, three themes were revealed as the primary reason for dropping out of school: non-responsive school culture, lack of supportive environment, and social factors. It was evident in the data collected that the school culture was unfavorable toward their learning and in meeting successful graduation requirements. Under non-responsive school culture, the following subthemes emerged as underlining factors to their dropping out: (a) low expectations, (b) non-caring for the student, (c) ineffective curriculum content, and (d) social issues at school. School-related factors such as the lack of a supportive environment revealed the following subthemes: (a) symptoms of school failure, (b) negative learning environment, and (c) culturally non-responsive instruction. Other attributing factors for dropping out of school included family structures and peer pressure. While each of the participants had unique experiences, each attributed non-responsive school culture, lack of supportive environment, and social context as major factors for dropping out of school. Therefore, the significance of this study lies in the potential to impact Mexican American student achievement in the reduction of dropouts.

This dissertation is aimed towards using stimuli-responsive pNIPAm-co-AAc microgels synthesized via free-radical precipitation polymerization to prepare stimuli-responsive hydrogel microlenses. Chapter 1 gives a detailed background of hydrogels, and their applications using responsive hydrogels. Chapter 2 describes the use of colloidal hydrogel microparticles as microlens elements and the fabrication method to form the hydrogel microlens arrays via Coulombic interactions. Chapter 3 shows the demonstration of tunable microlenses prepared by the method used in Chapter 2. In this chapter the microlenses are subjected to various pH and temperature in aqueous solutions. Chapter 4 describes that the microlens arrays constructed on Au nanoparticle-functionalized glass substrates by self-assembly display dramatic changes in lensing power in response to an impingent frequency-doubled Nd:YAG laser. The microlens photoswitching is highly reversible, with sub-millisecond lens switching times. Chapter 5 describes the development of bioresponsive hydrogel microlenses as a new protein detection technology. The microlens method is shown to be very specific for the target protein, with no detectable interference from nonspecific protein binding. Chapter 6 describes the use of bioresponsive hydrogel microlenses as a label-free biosensing scaffolding. These microstructures simultaneously act as the biosensors scaffolding/immobilization architecture, transducer, amplifier, and also allow for broad tunability of the analyte concentration to which the microlens is sensitive.

Ultraviolet B (UVB) radiation from the sun is the chief cause of skin cancer and is also involved in the development of Vitamin D in humans. This poses an interesting challenge, especially for people living in locations at mid to high latitudes. Through an integrative research review and controlled testing the amount of UVB humans receive in the landscape has been explored. Two existing computer models along with personal dosimeter badges were used to evaluate how much UVB students at a school in Waterloo, Ontario received under various conditions in February, 2013. Results showed that it is possible to get the equivalent of 1000 I.U. of vitamin D in February in Waterloo under ideal weather conditions, but not in most conditions. With this information, a guide has been created to optimize UVB for outdoor spaces in all seasons that children may use in northern climates. The design guide includes a summary of the geophysical variables that affect how much UVB reaches the earth’s surface and key concepts to understand including the difference between diffuse and direct radiation. This study provides evidence-based research in the area of climate responsive landscape architecture. / Landscape Architecture Canada Foundation