Three cage-functionalized polyoxacrown ethers (9, 10 and 12) and four novel cage-functionalized polyoxamonoazacrown ethers (18, 20, 25 and 29) that contain 3,5-disubstituted-4-oxahexacyclo[5.4.0.02,6.03,10.05,9.08,11]dodecane ("oxahexacyclic") moiety have been synthesized and their respective alkali metal picrate extraction profiles along with that of three analogues 13, 14 and 21 have been obtained. The observed avidities and selectivities of the host molecules toward complexation and transport of alkali metal picrates can be related to the size and shape of their respective macrocyclic cavity and the number of donor atoms. The effect of N-alkyl substitution on the complexation properties of azacrown ethers has been studied. The avidity of N-Et azacrown ethers toward complexation with alkali metal cations is generally higher than that of the corresponding non-N-alkylated hosts. However, the presence of an N-Et group appears to have a negligible effect upon their relative selectivities in their regards. The effect of pH on extraction process was studied; it was thereby determined that the alkali metal picrate extraction experiments are best performed at high pH (ca. 11-12).

The purpose of this study was to induce an oxidative-stress adaptation in Listeria monocytogenes Bug600 (serotype 1/2a) and F1057 (serotype 4b) by pre-exposing to sublethal H2O2 and alkali-stress either singly or sequentially. Our findings show that the sequential pre-exposure of cells to pH 9 for 30 min treatment followed by 50 ppm H2O2 for 30 min at 37°C yielded the highest oxidative-stress resistant phenotypes of L. monocytogenes Bug600 and F1057. The sublethal H2O2 and sublethal alkali-stress induced oxidative-stress adaptations were completely reversible within 60 min at 37°C in the absence of such sublethal stress. However, the oxidative-stress adaptation induced at 37°C was stable at 4°C over a 24 h test period in both L. monocytogenes Bug600 and F1057. Future studies will focus on the potential cross-resistance of oxidative-stress adapted L. monocytogenes serotypes 1/2a and 4b to commonly used disinfectants and GRAS antimicrobials.

The purpose of this study is to determine the effect of temperature on inducing an alkaline-tolerance response in L. monocytogenes (Lm) serotypes 1/2a and 4b. When Lm cells were pre-exposed to a sublethal alkali pH of 9.0 at different temperatures, two main patterns were observed: (1) Alkali-stress adaptation was readily induced in Lm when cells were pre-exposed to a sublethal alkali pH of 9.0 for 5-15 min at 37°C or 22°C; and (2) Alkali-stress adaptation was not induced in Lm when cells were pre-exposed to a sublethal alkali pH of 9.0 for 1 h at 4°C. However, exposure of Lm to 4°C for 24 h enhanced its survival against lethal alkaline challenge (pH 11.5). Also, alkali-stress adaptation if occurred at 37°C or 22°C was highly stable at 4ºC even in the absence of mild alkaline stress which should be taken into account while conducting risk analysis for this pathogen.

No description available.

N/A / Thesis / Bachelor of Science (BSc)

<p> Measurements of the infrared absorption spectra of potassium and sodium halide crystals with substitutional H- ion impurities are presented and compared with calculations which use rigid ion and ordinary shell models for the defect along with phonon data obtained from inelastic neutron scattering measurements. It is shown that the shell model is necessary to give a satisfactory account of the observed anharmonic side band absorption in the sodium halide crystals and that it improves the rigid ion results for the potassium halide crystals. The same model also satisfactorily describes the impurity induced far-infrared absorption in these materials. Some Van Hove singularities observed in the far infrared measurements occur at frequencies predicted from phonon densities of states calculated from neutron scattering data while others occur at slightly different frequencies.</p> / Thesis / Doctor of Philosophy (PhD)

Tensile fracturing and expansion possible relating to tectonic activity and faulting have in part controlled the emplacement of alkali feldspar rich rocks in Heronian sediments at Lake La Cloche, south of Massey, Ontario. The rocks include 1. albitite - composed almost entirely of low albite (Dr2-Abg95-An3) and minor dispersed hematite. 2. perthosite - containing separate phases of microcline and albite with mutual replacement textures. The seem to be physically separate but show similarities in spatial, textural and chemical aspects. They have been emplaced chiefly within a fracture zone at the top of the Mississagi quartzite. Perthosite is intimately related with 3. tuffisite - a somewhat mineralogically and modally variable rock emplaced as matrix within an irregular breccia pipe north of the fracture zone. The overall mineral assemblage is microcline + albite + perthite + epidote + chlorite + sericite+ hematite. Texturally it is reminiscent of crystal cuffs. Phenoclasts of the alkali feldspars (rounded, abraded) float in a hydrous silicate background. These phenoclasts are replicas of those in perthosite. Fragments of perthosite (phenoclast poor) were also found in tuffisite in one local. Tuffisite ranges from alkali feldspar poor to feldspar rich varieties. It is typically a silica poor alumina, lime, iron arid potash-rich rock. Tuffisite was probably emplaced as a fluidized mass. Some similarities to known fluidized bodies are present. These include rounding, attrition and fretting of the host rock, extensive penetration and exploitation of joints, bedding and planar weaknesses, internal sculpturing of the host rock, evidence for both mechanical and chemical emplacement. It may also be classed as a hydrothermalite. This refers to crytallization under submagmatic conditions, the pneumatolytic to hydrothermal range, hydroxyl minerals commonly developing. In this respect and others it is comparable with weilbergites, alkali feldspar-chlorite rocks within the Lahn region of Germany. Certain nearby breccia pipes and red feldspar rocks have been associated with alkalic igneous activity. (An alkaline rock province has been postulated along the North Shore of Lake Huron) Specif1cally soda rich fenite breccias are present at Nemag and Kusk lakes, 12 miles southwest of Sudbury. The red feldspar rock albitite is common along the North Shore. It is often adjacent or spatially related to diabase and has been interpreted accordingly in terms of genesis. Some albitites are not related spatially to di abase bodies and their emplacement has been controlled fracture systems. Their origin is more hazy. The author suggests two alternative interpretations dependent on whether alkali feldspars in tuffisite are considered to be primarily on- allochthonous. Alternative One - (Alkali feldspars primary): Perthosite and albitite are special fractionates, concentrated initially within the proto-tuffisite magma aj an al kali-volatile rich phase. These juvenile liquids were emplaced within a fracture zone at the top of the Mississagi. At about the same time tuffisite was emplaced within an irregular breccia pipe. The author throws open for argument the possibility that tuffisite is an upper crustal altered fenite breccia with associated red feldspar rock emplacement la fracture zones. Alternative Two-(Alkali feldspars allochthonous);Tuffisite is a hybrid rock type akin to a weilbergites (also interpreted as hybrid). Crystallization of red feldspar rocks within the pneumatolytic stage involved contamination in part by mafic material (possibly diabase). The resultant mechanical, chemical mixture was emplaced as a fluidized mass-tuffisite. More work needs to be done in determining which alternative is valid and what the exact relationships and sources of albitite, perthosite and tuffisite are. / Thesis / Bachelor of Science (BSc)

No description available.

No description available.

In this study, a sustainable packaging system was developed to provide food safety and security. Soy protein isolate (SPI) was enzymatically modified by transglutaminase under different conditions to ensure desirable and optimized enzyme crosslinking activity before film preparation. Physicochemical properties including viscosity and molecular weight distribution of the modified proteins and films were measured. Results confirmed the enzymatic treatment is an effective way to modify the SPI based biopolymeric film. Modified films with the enzyme had significant increases in tensile strength (TS), percent elongation (%E), initial contact angle, and a reduction in swelling and protein solubility properties compared to the control films. FTIR and XRD spectra revealed that the enzyme treatment modified the structure of SPI film matrix. The optimal film preparation conditions achieved in this part were protein denaturation temperature 80 °C, and enzyme incubation time 2hr. We attempted to enhance antioxidant activity of enzymatically modified SPI film with the addition of two types of lignin, alkali lignin (AL) and lignosulphonate (LSS), at different concentrations. Results indicated that AL carried higher radical scavenging ability than LSS. Films containing AL showed high absorption in the UV region, and this UV-blocking ability increased with increasing lignin concentration. Deconvoluted FTIR spectra and XRD results suggested that the addition of lignin caused some changes in secondary structure of the protein matrix. The addition of lignin improved TS and thermal stability of films, but reduced %E as a function of lignin concentration. Radical scavenging activity and UV-blocking ability alongside improvement in physicochemical properties of enzymatic modified SPI film with lignin motivated us to apply this bioplastic in two types of oil, soy oil and fish oil. Results revealed that applying enzymatically modified SPI film with AL and LSS in the inner layer of a soy oil packaging system, decreased oxidation rate to around 75%, and pentanal production to about 40% of control. UV-blocking ability of AL caused reduction in oxidation rate for more than 75% compared with the normal packaging system. The effectiveness of this active packaging system in soy oil was greater than fish oil. Thus, the developed biopolymeric materials may have application to food packaging. / Ph. D.