Cataract is one of the leading causes of vision loss worldwide. The rate of cataract surgery has been steadily increasing. Toxic Anterior Segment Syndrome (TASS) is a sterile inflammatory response in the anterior segment of the eye that may occur following cataract surgery. When left untreated, it can lead to permanent vision loss. Corneal endothelial cells are the cells most affected by TASS. These cells are unable to reproduce in vivo and consequently once the density of these cells drops below a certain level, vision is reduced and cannot be reversed. The damage is thought to be mediated by cytokines and endotoxins, primarily through the NF-κΒ pathway. It is hypothesized that anti-inflammatory drug delivery intraocular lenses may help reduce the occurrence of TASS and consequent vision loss. In this research thesis project, an in vitro model was developed as a tool to select drug and delivery material to be used in an anti-TASS ophthalmic biomaterial. In an attempt to find a novel and more effective approach to TASS prevention, dexamethasone, a potent anti-inflammatory steroid drug, was compared to triptolide, a cytokine inhibitor; aprotinin, a general protease inhibitor; and PPM-18, a NF-κΒ inhibitor. To assess the efficacy of these drugs, an in vitro assay using human umbilical vein endothelial cells (HUVEC) and lipopolysaccharide as a stimulant was developed. Cell response to dexamethasone (10 nM), triptolide (3 nM), aprotinin (20 μM) and PPM-18 (10 μM) with or without LPS was characterized by cell viability and flow cytometry analysis of cell activation. Activation was characterized using markers for cell adhesion and activation ICAM-1, PECAM-1, VCAM-1, β1-integrin, CD44 and E-selectin. Following preliminarily testing, the efficacy of dexamethasone (10 nM) and PPM-18 (10 μM) loaded polymer (PDMS) and copolymer (PDMS/pNIPAAm) interpenetrating polymer networks were evaluated over a 4 day release period. The results from soluble drug and LPS (100 ng/mL) testing indicated no decrease in cell viability after 24 h. Dexamethasone, triptolide, aprotinin, and PPM-18 did not reduce the significant ICAM-1 upregulation seen in HUVECs after exposure to LPS for 4 days. PPM-18 in combination with LPS significantly upregulated E-selectin iv and CD44 from unstimulated HUVEC cells. The polymer materials without drug loading did not influence the cell phenotype. However, PPM-18 delivering polymer and copolymer materials significantly upregulated VCAM-1, CD44 when compared to all other treatments. Propidium iodide uptake in HUVEC exposed to PPM-18 drug delivering polymer and copolymer treatments indicated that these treatments caused cell necrosis. None of the drugs, or the drug delivering materials were shown to counteract the upregulation seen from LPS stimulation of HUVEC cells. Future work should focus on validating the in vitro model to more closely replicate the in vivo environment of the anterior segment with the use of primary bovine corneal endothelial cells.

This study was carried out for understanding of antioxidant mechanisms of lentil under abiotic stress conditions. For this aim, 14 days old lentil seedlings (Lens culinaris Medik cv. Sultan-1) were subjected to drought (20% PEG 6000), and salt (150 mM NaCl ) stress for 6, 12 and 24 hours, for 3, 5 and 7 days. PCR conditions for Mn SOD, Cu/Zn SOD, chloroplastic/mitochondrial GR, CAT and chloroplast /stromal APX antioxidant enzymes were optimized. Then, total RNA was isolated from stressed and non-stressed plant roots and shoots. The gene expression levels of Mn SOD and Cu/Zn SOD were examined by semi-quantitative reverse transcription polymerase chain reaction (RT-PCR) technique. Arabidopsis 18S rRNA was used as internal control in multiplex PCR technique. Relative expression levels of Mn SOD were lower in shoots and roots under salt stress while no significant change was obtained under drought conditions in both tissues. Relative expression levels of Mn SOD were increased on 5th day of salt and drought applications in both shoots and roots. Relative expression levels of Cu/Zn SOD increased after 5th, and on 1st and 7th days of drough treatment in shoots and roots, respectively. On the other hand, expression levels of Cu/Zn SOD increased on 3rd and 5th days of salt treatment in shoot tissues. Although it is nearly impossible to understand the whole antioxidant mechanism of plants under environmental stresses, this study was the first step to learn about molecular background of antioxidant defence mechanisms in lentil.

Diss. (sammanfattning) Umeå : Umeå universitet, 2010. / Härtill 4 uppsatser. Även tryckt utgåva.

The optical design of a LED illuminator and camera imaging system were studied for potential use in a small medical "robotic type" probe to be used for minimally invasive abdominal surgery. Beam shaping optical reflectors were studied to increase the intensity distribution of the LED beam directed toward a close-by target surface. A CMOS/CCD camera and lens was used to image the targeted area. In addition, extensive optical ray tracing simulations were made to predict the intensity patterns. The experimental measurements and ray tracing simulations were in good agreement, and indicated that 20 degree cone reflectors for the LED sources and appropriate micro-lens/CCD chip imaging optics should provide a useful image at a working distance of about 5 cm.

Eddy-covariance (EC) CO₂ flux data were analysed and annual carbon (C) balances estimated for a four-year period (2004-2007) following clearcut harvesting of a boreal jack pine stand in northern Saskatchewan. The site was a source of C to the atmosphere for all years, with annual net ecosystem productivity (NEP) increasing from -153 g C m⁻² yr⁻¹ in 2004 to -63 g C m⁻² yr⁻¹ in 2007. This increase was mainly due to gross primary productivity (GPP) increasing significantly from 78 to 200 g C m⁻² yr⁻¹ , while ecosystem respiration (R) increased only slightly from 231 to 263 g C m⁻² yr⁻¹ over the same period. In the 2006 growing season (GS), a field campaign was conducted to investigate the relationships between monthly destructive measurements of leaf area index (LAI) and daily measurements of the normalized difference vegetation index (NDVI) and photosynthetic capacity (Amax). The latter was derived from 5-day, 16-day, 30-day and annual Michaelis-Menten light response analyses using daytime measurements of NEP and incident photosynthetically active radiation. Digital-camera data were used to evaluate the potential of using the rectilinear-lens vegetation index (RLVI) as a surrogate for NDVI of a young forest stand. Results showed that LAI was linearly related to NDVI and RLVI, which was largely the result of changes in the deciduous vegetation component across the GS. These results indicate that RLVI could be used as a surrogate for NDVI up to a GS maximum LAI of 0.91 m2 m⁻² observed in 2006. Measured mean (± 1 S.D.) GS LAI was 0.67 (± 0.24) m² m⁻² in 2006. LAI accounted for the majority of the variability in Amax at the 30-day time scale, while at shorter time scales air temperature was the dominant control. For 2004 to 2007, mean spring estimates of LAI were 0.25, 0.29, 0.38 (compared to 0.40 m² m⁻² from measurements) and 0.41 m² m⁻², respectively. Results suggest that a steady increase in the jack pine LAI component accounted for the annual increases in GPP and hence NEP over the four years.

In addition to the canonical photoreceptors, rods and cones, a novelmelanopsin-expressing retinal ganglion cell (mRGC) was recently discovered.The novel photopigment melanopsin in the human retinahas been shown to express invertebrate-like bistable properties bothin vitro and in vivo. In bistable photopigment systems, light elicitsphotosensory responses and drives photoregeneration of the chromophoreto restore photic responsiveness. These studies have shownthat prior light exposure can modulate the amplitude of subsequentphotic responses of melanopsin.In this thesis, the putative bistability of melanopin in humans isexamined. The bistability was studied using 1) pupillary light reflex(PLR) as a tool, 2) developing a method for quantifying the effectsof lens density for melanopsin-mediated photoreception, and 3) providinga quantitative mathematical framework for modeling bistablepigment systems and non-image forming (NIF) visual system.Exploiting the bistable properties of melanopsin could allow foroptimization of spectral light distribution in experimental, industrial,domestic and clinical phototherapy applications by appropriate useof the photoregenerative effects of long wavelength light.

The purpose of this study is to explore the beliefs, attitudes, and practices of principals with regard to equity and inclusion specific to hiring teachers from diverse backgrounds. A qualitative design and narrative analysis guided this study. Twelve principals and vice-principals from six high schools in one school district in Ontario participated in the study by answering questions on a self-completion web questionnaire. The findings were analyzed using four categories with regard to hiring diverse teachers: 1) current understanding of diversity in the school community; 2) current practices for diversity hiring; 3) beliefs and attitudes for diversity hiring and existing barriers; 4) solutions and future learning opportunities. Data were analysed using thematic analysis. The overall themes that emerged from the data were: a) valuing the importance of diversity, equity, and inclusion; b) not valuing diversity and providing rationale for not considering diversity and equity. The findings revealed that principals were able to define diversity in their own words. However, principals did not always value diversity in teacher candidates in their hiring practices. The questions used by principals to interview teachers – based on those recommended by the school board’s interview questions – did not include questions that would elicit and support responses from teacher candidates with regard to teaching diverse students or that reveal the value of their own diversity. The findings revealed that there are various barriers due to biases, hiring attitudes and current practices. Finally, the findings revealed that some principals are resistant to additional learning and professional development activities, saying they see no barriers for diverse teacher candidates being hired. However, some principals are open to more training and learning opportunities and see professional development as a catalyst in bringing positive change with respect to hiring practices and valuing diversity. A discussion of the findings with reference to current literature is provided. In conclusion, questions and approaches for further studies are identified.

The goal of the research reported in this thesis is to establish the feasibility of a novel optical architecture for an optical route & select circuit switch suitable for implementation as a photonic integrated circuit. The proposed architecture combines Optical Phased Array (OPA) switch elements implemented as multimode interference coupler based Generalised Mach-Zehnder Interferometers (GMZI) with a planar Lüneburg lens-based optical transpose interconnection network implemented using graded metamaterial waveguide slabs. The proposed switch is transparent to signal format and, in principle, can have zero excess insertion loss and scale to large port counts. These switches will enable the low-energy consumption high capacity communications network infrastructure needed to provide environmentally-friendly broadband access to all. The thesis first explains the importance of switch structures in optical communications networks and the difficulties of scaling to a large number of switch ports. The thesis then introduces the Talbot effect, i.e. the self-imaging of periodic field distributions in free space. It elaborates on a new approach to finding the phase relations between pairs of Talbot image planes at carefully selected positions. The free space Talbot effect is mapped to the waveguide Talbot effect which is fundamental to the operation of multimode interference couplers (MMI). Knowledge of the phase relation between the MMI ports is necessary to achieve correct operation of the GMZI OPA switch elements. An outline of the design procedures is given that can be applied to optimise the performance of MMI couplers and, as a consequence, the GMZI OPA switch elements. The Lüneburg Optical Transpose Interconnection System (LOTIS) is introduced as a potential solution to the problem of excessive insertion loss and cross-talk caused by the large number of crossovers in a switch fabric. Finally, the thesis explains how a Lüneburg lens may be implemented in a graded ‘metamaterial’, i.e. a composite material consisting of ‘atoms’ arranged on a regular lattice suspended in a host by nano-structuring of silicon waveguide slabs using a single etch-step. Furthermore, the propagation of light in graded almost-periodic structures is discussed. Detailed consideration is given to the calibration of the local homogenised effective index; in terms of the local parameters of the metamaterial microstructure in the plane and the corrections necessary to accommodate slab waveguide confinement in the normal to the plane. The concept and designs were verified by FDTD simulation. A 4×4 LOTIS structure showed correct routing of light with a low insertion loss of -0.25 dB and crosstalk of -24.12 dB. An -0.45 dB excess loss for 2D analysis and an -0.83 dB insertion excess loss for 3D analysis of two side by side metamaterial Lüneburg lenses with diameter of 15 μm was measured, which suggests that the metamaterial implementation produces minimal additional impairments to the switch.

Clinical decision rules improve health care fidelity, benefit patients, physicians and healthcare systems, without reducing patient safety or satisfaction, while promoting cost-effective practice standards. It is critical to appropriately and consistently apply clinical decision rules to realize these benefits. The objective of this thesis was to understand how physicians use the Ottawa Ankle Rules to guide radiography decision-making. The study employed a clinical judgment survey targeting members of the Canadian Association of Emergency Physicians. Statistical analyses were informed by the Brunswik Lens Model and Social Judgment Analysis. Physicians’ overall agreement with the ankle rule was high, but can be improved. Physicians placed greatest value on rule-based cues, while considering non-rule-based cues as moderately important. There is room to improve physician agreement with the ankle rule and use of rule-based cues through knowledge translation interventions. Further development of this Lens Modeling technique could lend itself to a valuable cognitive behavioral intervention.

Cataract is one of the leading causes of vision loss worldwide. The rate of cataract surgery has been steadily increasing. Toxic Anterior Segment Syndrome (TASS) is a sterile inflammatory response in the anterior segment of the eye that may occur following cataract surgery. When left untreated, it can lead to permanent vision loss. Corneal endothelial cells are the cells most affected by TASS. These cells are unable to reproduce in vivo and consequently once the density of these cells drops below a certain level, vision is reduced and cannot be reversed. The damage is thought to be mediated by cytokines and endotoxins, primarily through the NF-κΒ pathway. It is hypothesized that anti-inflammatory drug delivery intraocular lenses may help reduce the occurrence of TASS and consequent vision loss. In this research thesis project, an in vitro model was developed as a tool to select drug and delivery material to be used in an anti-TASS ophthalmic biomaterial. In an attempt to find a novel and more effective approach to TASS prevention, dexamethasone, a potent anti-inflammatory steroid drug, was compared to triptolide, a cytokine inhibitor; aprotinin, a general protease inhibitor; and PPM-18, a NF-κΒ inhibitor. To assess the efficacy of these drugs, an in vitro assay using human umbilical vein endothelial cells (HUVEC) and lipopolysaccharide as a stimulant was developed. Cell response to dexamethasone (10 nM), triptolide (3 nM), aprotinin (20 μM) and PPM-18 (10 μM) with or without LPS was characterized by cell viability and flow cytometry analysis of cell activation. Activation was characterized using markers for cell adhesion and activation ICAM-1, PECAM-1, VCAM-1, β1-integrin, CD44 and E-selectin. Following preliminarily testing, the efficacy of dexamethasone (10 nM) and PPM-18 (10 μM) loaded polymer (PDMS) and copolymer (PDMS/pNIPAAm) interpenetrating polymer networks were evaluated over a 4 day release period. The results from soluble drug and LPS (100 ng/mL) testing indicated no decrease in cell viability after 24 h. Dexamethasone, triptolide, aprotinin, and PPM-18 did not reduce the significant ICAM-1 upregulation seen in HUVECs after exposure to LPS for 4 days. PPM-18 in combination with LPS significantly upregulated E-selectin iv and CD44 from unstimulated HUVEC cells. The polymer materials without drug loading did not influence the cell phenotype. However, PPM-18 delivering polymer and copolymer materials significantly upregulated VCAM-1, CD44 when compared to all other treatments. Propidium iodide uptake in HUVEC exposed to PPM-18 drug delivering polymer and copolymer treatments indicated that these treatments caused cell necrosis. None of the drugs, or the drug delivering materials were shown to counteract the upregulation seen from LPS stimulation of HUVEC cells. Future work should focus on validating the in vitro model to more closely replicate the in vivo environment of the anterior segment with the use of primary bovine corneal endothelial cells.