The commensal Streptococcus gordonii expresses numerous surface adhesins with which it interacts with other microorganisms, host cells and salivary proteins to initiate dental plaque formation. However, this Gram-positive bacterium can also spread to non-oral sites such as the heart valves and cause infective endocarditis. One of its surface adhesins, Sgo0707, is a large protein composed of a non-repetitive N-terminal region followed by several C-terminal repeat domains and a cell wall sorting motif. Here we present the crystal structure of the Sgo0707 N-terminal domains, refined to 2.1 Å resolution. The model consists of two domains, N1 and N2. The largest domain, N1, comprises a putative binding cleft with a single cysteine located in its centre and exhibits an unexpected structural similarity to the variable domains of the streptococcal Antigen I/II adhesins. The N2-domain has an IgG-like fold commonly found among Gram-positive surface adhesins. Binding studies performed on S. gordonii wild-type and a Sgo0707 deficient mutant show that the Sgo0707 adhesin is involved in binding to type-1 collagen and to oral keratinocytes.

Photonic crystals (PC) are periodic structures that dictate the behavior of electromagnetic radiation and can be one-dimensional, two-dimensional or three-dimensional (3D). A 3DPC was modeled and fabricated based on a three-layer design resulting in a face centered cubic structure. Different simulation methods were used to show the existence of a complete 3D bandgap, and were verified experimentally by obtaining transmission measurements in several directions. A prototype of the structure was fabricated using ECCOSTOCK HiK high dielectric sheets (dielectric of 12) and machined using a computer and numerical controlled mill. Experiments to test this structure were performed in an anechoic chamber making use of a network analyzer, a pair of horn antennas, collimating lenses, and a track for alignment. Free-space Thru-Reflect-Line measurements were taken between 10GHz and 15GHz to obtain the transmission through the prototype. Finally, a defect layer was added to the structure at different locations and localized modes observed.

Photonic crystals (PC) are periodic structures that dictate the behavior of electromagnetic radiation and can be one-dimensional, two-dimensional or three-dimensional (3D). A 3DPC was modeled and fabricated based on a three-layer design resulting in a face centered cubic structure. Different simulation methods were used to show the existence of a complete 3D bandgap, and were verified experimentally by obtaining transmission measurements in several directions. A prototype of the structure was fabricated using ECCOSTOCK HiK high dielectric sheets (dielectric of 12) and machined using a computer and numerical controlled mill. Experiments to test this structure were performed in an anechoic chamber making use of a network analyzer, a pair of horn antennas, collimating lenses, and a track for alignment. Free-space Thru-Reflect-Line measurements were taken between 10GHz and 15GHz to obtain the transmission through the prototype. Finally, a defect layer was added to the structure at different locations and localized modes observed.

Crystal meth has been an illicit drug for many years but did not surface as a problem until the 1990s. Between 200 and 2006, a number of provincial documents were produced in British Columbia, Alberta and Saskatchewan to examine this problem. A shift appeared to have occurred in terms of how to handle this situation. Traditionally, illicit drugs such as crystal meth were dealt with by the criminal justice system; however, in this case, provincial health departments prepared these documents. The intent of this thesis is to examine these documents by providing a discourse analysis and applying concepts from Foucault, vanDijk and Phillips and Hardy. Three questions are asked: (i) who are the voices of these documents? (ii) who is identified as being at risk? and (iii) how is crystal meth socially constructed and what solutions are presented? All three provinces identify the same at risk population, our youth. British Columbia and Saskatchewan construct crystal meth as an educational and health problem, while Alberta focuses mainly on crystal meth as being a criminal problem. This research concludes that the solutions offered by the various experts from these provinces are unrealistic. The social determinants of health such as adequate income, housing and employment opportunities are discussed in these provincial documents however, nothing concrete is provided. Saskatchewan is the only province to commit money to finance new programs to assist with the crystal meth problem.

Photovoltaic processing is one of the processes that have significance in semiconductor process line. It is complicated due to the no. of elements involved that directly or indirectly affect the processing and final yield. So mathematically or empirically we can’t say assertively about the results specially related with diffusion, antireflective coating and impurity poisoning. Here I have experimented and collected data on the mono-crystal silicon wafers with varying properties and outputs. Then by using neural network with available experimental data output required can be estimated which is further tested by the test data for authenticity. One can say that it’s a kind of process simulation with varying input of raw wafers to get desired yield of photovoltaic mono-crystal cells.

There is evidence for the existence of non-classical bonding in several binary antimonides, selenides, and tellurides. Owing to such non-classical bonding, some of these solid materials exhibit exciting semiconducting and thermoelectric properties, which make them attractive from a technological view point. However, lack of efficiency is a serious limitation in most of those thermoelectrics. It is very crucial, hence, to find new materials with superior properties and understand the structure and bonding in such materials, in order to facilitate the fine-tuning of the physical properties. With this expectation, several quaternary barium copper chalcogenides are synthesized and characterized in the present study. The chalcogen elements, selenium tellurium, are used in various ratios, in order to understand and tune the binding interactions. Extensive single crystal x-ray diffraction studies are expected to reveal the minute details of the bonding interactions together with electronic structure calculation and physical property measurements. In addition, characterization techniques such as powder x-ray diffraction, electron microscopy, differential scanning calorimetry, thermopower and conductivity measurements are utilized. The ternary and quaternary chalcogenides, Ba₂Cu₄₋ₓSeyTe₅₋y were synthesized from the elements in stoichiometric ratios at 700°C, followed by annealing at 600°C. The ternary telluride Ba₂Cu₄₋ₓTe₅ crystallizes in a new structure type, space group C2/c, with lattice dimensions of a = 9.4428(6) Å, b = 9.3289(6) Å, c = 13.3028(8) Å, β = 101.635(1)°, V = 1147.8(1) Å3, for x = 0.75(1) (Z = 4). The corresponding selenide-telluride adopts another new, but strongly related, structure type, space group P4₁2₁2, with a = 6.5418(3) Å, c = 25.782(2) Å, V = 1103.3(1) Å3, for Ba₂Cu₃.₂₆₍₂₎Se₀.₇₂₉₍₈₎Te₄.₂₇₁ (Z = 4). Between 0.13 and 1.0 Te per formula unit can be replaced with Se, while the Cu content appears to vary only within 0.67 ≤ x ≤ 0.81 for Ba₂Cu₄₋ₓSeyTe₅₋y. Despite crystallizing in different crystal systems, the telluride and the selenide-telluride exhibit topologically equivalent structure motifs, namely chains of Cu(Se,Te)₄ tetrahedra with a Cu atom cis/trans chain as well as an almost linear Te atom chain. All these chalcogenides - as far as measured - are p-doped semiconductors, as determined by Seebeck coefficient and electrical conductivity measurements. Two new orthorhombic chalcogenides, Ba₂Cu₆₋ₓSeyTe₅₋y and Ba₂Cu₆₋ₓSyTe₅₋y were synthesized at 800°C. They are isostructural and crystallize in a new structure type, with space group Pbam. Ba₂Cu₆₋ₓSyTe₅₋y, with a = 9.6560(6) Å, b = 14.0533(9) Å, c = 4.3524(3) Å and Ba₂Cu₅.₆₄Se₁.₀₉Te₃.₉₁with a = 9.7048(6) Å, b = 14.1853(9) Å, c = 4.3840(3) Å. They have Cu6 units extending along c-axis, and two such units are interconnected by S or Se atoms along a-axis. These compounds are nonmetallic with low Seebeck coefficients. Two more new quaternary chalcogenides were uncovered, BaCu₅.₉₂₆₍₁₅₎SeTe₆ and BaCu₅.₇₂₍₁₆₎Se₀.₄₆₄₍₁₅₎Te₆.₅₃₆ with a = 6.9680(2) Å and a = 6.9888(4) Å, respectively, in space group Pm̅3. These compounds have basic Cu₈Te₁₂ frameworks, which can be an important feature for thermoelectric materials. Ba occupies the void. One Cu atom from each cage cluster of eight such cages forms a Cu₈ cube with Se atom occupying it. BaCu₅.₉SeTe₆ was experimentally determined to be p-type doped semiconductor with moderate Seebeck coefficient value.

Crystal meth has been an illicit drug for many years but did not surface as a problem until the 1990s. Between 200 and 2006, a number of provincial documents were produced in British Columbia, Alberta and Saskatchewan to examine this problem. A shift appeared to have occurred in terms of how to handle this situation. Traditionally, illicit drugs such as crystal meth were dealt with by the criminal justice system; however, in this case, provincial health departments prepared these documents. The intent of this thesis is to examine these documents by providing a discourse analysis and applying concepts from Foucault, vanDijk and Phillips and Hardy. Three questions are asked: (i) who are the voices of these documents? (ii) who is identified as being at risk? and (iii) how is crystal meth socially constructed and what solutions are presented? All three provinces identify the same at risk population, our youth. British Columbia and Saskatchewan construct crystal meth as an educational and health problem, while Alberta focuses mainly on crystal meth as being a criminal problem. This research concludes that the solutions offered by the various experts from these provinces are unrealistic. The social determinants of health such as adequate income, housing and employment opportunities are discussed in these provincial documents however, nothing concrete is provided. Saskatchewan is the only province to commit money to finance new programs to assist with the crystal meth problem.

This work presents a novel loss-reduced photonic liquid-crystal fiber (PLCF) using the non-contact photo-alignment method. The photo-excited and adsorbed azo dye on the capillary surface of a PLCF induces uniform and highly ordered orientation of the LC. The anchoring force of the photo-alignment effect is combined with that generated by surface boundary conditions of the photonic crystal fiber (PCF). Transmission loss resulting from LC scattering can be reduced from -2.8db/cm to -1.3db/cm within 10min. This photo-induced alignment yields a permanent boundary for the LC in the PCF that reduces scattering loss, and can be further modulated by electrical fields. The electrical tunable effect and fast dynamic response of the photo-aligned PLCF are also presented. This low-loss PLCF can be applied conveniently in various PLCF devices.

Modal birefringence and stress distribution measurement in doubt-clad rare-earth-doped fibers are reported. For example, doubt ¡Vclad ytterbium-doped fiber and doubt ¡Vclad neodymium -doped fiber. In this paper, I am interested in the effect of fabrication on birefringence of Cr4+: YAG double-clad crystal fiber. A knowledge of stress distribution in the fiber would indicate the origin of birefringence.Since fiber birefringence can be produced by different mechanisms.For example,stress-induced birefringence,geometrical anisotropy of a non-circular fiber core and inner-cladding, intrinsic birefringence, fiber bending and twist.To understand the origin of birefringence, I have obtained the stress distribution pattern in Polarization Optical Microscopy.Using scanning wavelength method (Phase Retardation), I set-up the system successfully and measured the group modal birefringence of bulk:YVO4 crystal and Cr4+ :YAG double-clad crystal fiber. I also used Jones matrix, Mueller matrix,stress optics law, photoelastic and mathematical formulas on the estimated modal birefringence to calculate the stress intensity distribution and interference light conditions and estimate the modal birefringence ,and then compared with other rare earth-doped fiber.

In this study, we research the characteristic of light in the waveguide with etched ITO channels. The anisotropic of liquid crystal induces the index of reflection changed while applying alternative voltage. The etched ITO electrode will become waveguide in cell by applying alternative voltage. We observe the characteristic of light with different number of channels. Single ITO channel results graded type reflection index distribution, and it is similar to graded type optical fiber. We find that the laser beams will induce coupling in channels with many etched ITO channels.