The objects of this research were twofold: 1. To develop apparatus and experimental techniques to shorten the exposure times in the study of the vibrational Raman effect of liquids and liquids in the solid state. 2. To use the above in the investigation of the vibrational Raman spectra of the liquid and solid states of Carbon Disulfide. Concurrently, other workers were investigating the infrared absorption spectrum of CS2. The two projects, when integrated, should give a reasonably complete basis for the description of the CS2 molecule. / Science, Faculty of / Physics and Astronomy, Department of / Graduate

A method is described for measuring the preferential responses of fish to alterations in the chemical and physical nature of their environment. Changes in the responses of young chum salmon at various stages of growth to alterations in the environmental sea water content have been studied. The effects of small alterations in temperature (2 to 3 C° ) and in rates of flow of environmental liquids on the fishes' responses to salinity change, were also studied. Preliminary experiments on the responses of coho salmon fry to sea water are described. The results indicate that changes in the environmental sea water content, such as those encountered in the estuaries of salmon streams may exert a directive influence on the seaward movement of chum salmon fry. / Science, Faculty of / Zoology, Department of / Graduate

An attempt has been made to alter the degree of unsaturation of the body fats of goldfish (Carassius auratus) and correlate these changes with any modifications of heat tolerance subsequently exhibited by the fish. The goldfish were fed three different diets each containing a fat of different degree of unsaturation. The fats used were pilchard oil (iodine value of 181.7), herring oil (iodine value of 128.4.) and lard (iodine value of 66.2). Heat resistance was tested by holding the fish at a constant high temperature and observing the time to death. Variations in the ability of the groups to withstand high temperature were then compared to differences in the degree of unsaturation of their extracted fats. It was found that while diet could effect changes in the degree of unsaturation of the goldfish fats to approximately 54% of the theoretical level, and that these changes in turn modified the heat resistance of the goldfish, no quantitative relationship was established. / Science, Faculty of / Zoology, Department of / Graduate

The magneto-optical Faraday effect was used, to observe the spin-bath relaxation in Europium doped CaF₂ crystals at helium temperatures from 1.5 to 4.2° K. Theory shows that the magnitude of the Faraday rotation is proportional to the difference in population of the ground state doublet. The experimental method used in this thesis is the same as that which was successfully used by Glattli and by Griffiths. Pulsed microwave power at X-band frequencies was employed to disturb the equilibrium between the spin system and the bath. The observed relaxation time t was expected to have a T⁻¹ temperature dependence hut because of the orientation of the crystal in our dc magnetic field which resulted in the seven transition lines being close together, cross-relaxation effects produced a temperature dependence of approximately T⁻². It is suggested that exchange coupled pairs of Eu²⁺ and clusters involving Eu³⁺ may account for this temperature dependence rather than there being a phonon bottleneck present. The field dependence of the relaxation time was found not to be directly related to the resonance spectrum, The Eu²⁺ concentration of the crystals used in this thesis was .2% / Science, Faculty of / Physics and Astronomy, Department of / Graduate

Ritodrine is a beta-adrenergic agonist commonly used to inhibit premature labor contractions in women. The primary goal of ritodrine tocolysis is to prolong gestation, however, other indications may include fetal distress. The purpose of the current study was to examine the metabolic and behavioral effects of ritodrine in the fetus, using the chronically instrumented pregnant sheep as an experimental model. Ritodrine was infused continuously into 11 fetal lambs at a rate of 2.6 ug/minute for a period of 8, 12 or 24 hours. Samples were taken simultaneously at predetermined time periods from a fetal femoral artery, umbilical vein, maternal femoral artery and uterine vein for the analysis of fetal and maternal arterial and umbilical and uterine venous blood gases, acid-base status, hematocrit, ritodrine concentration, uterine and umbilical blood flow, and glucose, lactate and oxygen concentrations and fluxes. Cardiovascular and behavioral variables were monitored continuously. The average concentration of ritodrine in fetal arterial plasma was 20.0 ± 2.7 ng/ml (range 9.5 to 3 4.7 ng/ml) at the end of the infusion. This concentration is within the range of cord levels obtained in ritodrine exposed human fetuses at birth (7 to 79 ng/mL) . Fetal arterial plasma ritodrine levels at 8 hours post-infusion were still sufficiently elevated to exert considerable fetal effects. The apparent tolerance of the fetus to given plasma levels of drug varied considerably among animals. The infusion of ritodrine resulted in many typical beta-adrenergic receptor mediated responses in the fetus. Fetal arterial glucose levels rose to 79% above the control by the end of the infusion. This was associated with an increase in fetal glucose delivery (70% above the control), a decrease in the umbilical veno-arterial glucose concentration difference and a tendency for fetal glucose uptake to decline. Fetal arterial plasma lactate concentrations rose more than fivefold during the infusion of ritodrine. This was associated with a rise in fetal lactate delivery (540% above the control), a slight increase in the umbilical veno-arterial plasma lactate concentration difference and a tendency for fetal lactate uptake to rise. Fetal oxygen consumption rose progressively and significantly throughout the infusion of ritodrine and during the first 8 hours of post-infusion, reaching a maximum of 22% above the control by 8 hours post-infusion. Umbilical blood flow remained unchanged, therefore umbilical oxygen delivery was not increased to meet the additional oxygen demands of the fetus. The rise in fetal oxygen consumption was hence accomplished through an increase in fetal fractional oxygen extraction (from a control value of 32.0±1.1% to a maximum of 51.6±1.8% by 1.5 hours of infusion). The rise in fetal oxygen extraction resulted in concurrent declines in fetal arterial Po₂ (78% of the control) and O₂ content (55% of the control) and a widening of the veno-arterial oxygen content difference. By the end of the infusion, umbilical venous Po₂ and O₂ content values had also fallen significantly to 78% and 75% of the control respectively. These latter changes resulted in a concurrent 25% decline in fetal oxygen delivery which in turn contributed to the rise in fetal oxygen extraction. Fetal arterial and umbilical venous pH declined rapidly and significantly from control values of 7.370±0.004 and 7.401±0.005 to 7.274±0.025 and 7.306±0.023 respectively by the end of the infusion. The acidemia was reflected by significant declines in base excess values and appeared to be entirely metabolic in nature, resulting from elevated blood lactate levels. The acidemia likely contributed to the progressive fall in fetal blood O₂ content through a rightward shift of the oxyhemoglobin dissociation curve (Bohr effect). The rise in fetal oxygen consumption was reflected by a similar (although nonsignificant) increase in uterine oxygen consumption. Uteroplacental oxygen consumption appeared to remain unaltered. The rise in uterine oxygen consumption was not accompanied by a corresponding increase in uterine oxygen delivery, hence uterine oxygen extraction rose to 23.8±1.9% (from a control value of 19.5±1.6%) by 1.5 hours post-infusion. The rise in uterine oxygen extraction resulted in significant declines in uterine venous Po₂ and CO₂ values which likely contributed to the fall in fetal oxygen delivery. Fetal heart rate increased significantly to 21% (34 beats per minute, bpm) above the control (162±7 bpm) during the first 1.5 hours of ritodrine infusion. It remained elevated by an average of 16% (26 bpm) throughout the remainder of the infusion and the first 8 hours of post-infusion, returning to the control by the end of the post-infusion period. Fetal arterial pressure remained unchanged from the control (46.2±1.5 mm Hg). The incidence of fetal breathing activity fell significantly from an overall average control value of 43.2±2.6% to an average of 28.1±6.8% during the ritodrine infusion period. In most animals, breathing was most depressed near the end of the infusion. The incidence of low voltage electrocortical (ECoG) activity also fell significantly by an average of 7.5% while that of high voltage ECoG rose by 7.3%. Alterations in intermediate voltage activity were not observed. The incidence of fetal rapid eye movement also tended to fall by an average of 8.2% during the infusion of ritodrine. These behavioral changes may have resulted from the development of fetal hypoxemia, rather than as a direct effect of ritodrine. In conclusion, these data have demonstrated that ritodrine infusion to fetal lambs results in significant physiological and behavioral changes in the fetus. These effects may put the fetus at risk, particularly in situations where fetal oxygen delivery is already reduced, as in various states of compromised pregnancy. / Medicine, Faculty of / Obstetrics and Gynaecology, Department of / Graduate

The mycotoxin zearalenone is known for its harmful effects on livestock reproduction. Animal exposure occurs through feed sources colonized by Fusarium species which produce the mycotoxin. Since regular screening procedures for zearalenone are not conducted on Western Canadian barley, a survey was carried out to test for possible significant levels of contamination. All samples were found to be negative at a detection level of 500 ppb; therefore, feeds formulated from the barley samples sources would not likely cause zearalenone toxicosis problems in livestock. Also, an ELISA method, Agri-Screen™, developed by Neogen Corporation (Lansing, Michigan) was tested and found to be a simple and economical method for pre-screening of feed samples in the field. To study direct toxicological effects of zearalenone on in vitro murine blastocyst development, murine embryos were cultured in medium (Ham's F-10 + estrous cow serum) containing various levels of the mycotoxin. The critical concentration range for zearalenone to cause detrimental effects on blastocyst development was determined to be between 70-160 μg/ml medium. Additionally, a concentration effect on the length of time required to exert deleterious actions was demonstrated. At mycotoxin concentrations of 500 μg/ml medium and above, blastocysts degenerated after 6 h of culture. At a lower concentration level of 160 μg/ml, blastocysts were not affected until 28 h of culture. In order to investigate the direct toxicological effects of zearalenone on in vitro porcine pre-implantation embryo development, attempts were made to develop a successful culture system. Since a suitable system was not developed, toxicological studies were not possible. Possibly, steps in the recovery process could have resulted in detrimental effects before the embryos were placed in culture. Alternatively, the media chosen (Ham's F-10 + estrous cow serum; Minimum essential medium + fetal calf serum) may not be suitable for in vitro culture of porcine pre-implantation embryos. Finally, at a zearalenone concentration level (250 μg/ml medium) found to cause degeneration of murine blastocysts, the in vitro maturation of bovine oocytes in Tissue Culture Medium 199 was not affected. It was suggested that the surrounding cumulus layer acts as a barrier to prevent the mycotoxin from directly acting on the oocyte. / Land and Food Systems, Faculty of / Graduate

The study of the effects of damaging agents on living cells is of importance both for the assessment of the potential consequences of exposure, and for the advancement of medical technologies concerned with the treatment of cancer and other diseases. Such agents, however, are commonly studied at doses and levels of effect much higher than those seen in environmental or even medical exposures. Studies of cell survival after treatment with ionizing radiation, for instance, generally involve the measurement of dose-response over several decades of cell kill on a logarithmic scale. In contrast, cell survival rates for a typical clinical treatment dose are on the order of 50%. Survival measurements in this first decade of cell kill require that the exact fate of thousands of cells is determined in a single experiment. This is beyond human capabilities. Measurements at these levels of effect therefore require the development of a rapid, automated system of cell detection, characterization, and follow-up. The primary aim of this thesis was to test the hypothesis that the algorithms necessary for generating survival data with such an automated system can be developed to standards of accuracy comparable to those of an experienced human observer. Using an image cytometry device specifically designed for the detection and analysis of live, unstained cells, automated scanning procedures were optimized for selected cell lines, and means of maintaining appropriate focus levels during a scan were devised. Algorithms to distinguish cells from other objects detected in the flask were also developed. These performed with comparable accuracy, but at greater speed, than could be achieved by a human observer. Because the endpoint used in survival measurements is the ability of treated cells to proliferate to form colonies, the hypothesis that automated methods of assaying colony formation could be developed was also tested. Using rapidly collected, low resolution image data obtained at locations in the tissue culture vessel where individual cells had been detected on the day of treatment, it was found that the survival status at 70-90% of these locations could be determined automatically. Manual assessments were required at the remaining locations. The final objective of this thesis was to use the methods developed for automated sample selection and survival assessment to examine a question relevant to both radiotherapeutic applications and the understanding of mechanisms of radiation action. In particular, the Theory of Dual Radiation Action (Kellerer and Rossi, 1972), which predicts that the relative biological effectiveness (RBE) of different modalities of sparsely ionizing radiations may change dramatically with decreasing dose, was tested experimentally. Using two different mammalian cell lines, the experimental data in general rejected the predictions of this theory, although a modified theory, developed by the same authors, could accommodate the results. In summary, the data showed that there may be a slight dose dependence in the RBE of the radiations tested. Specifically, the RBE of low energy X-rays relative to ⁶⁰Co γ-rays was found to increase slightly with decreasing dose. The measured RBE's in the zero-dose limit were ~1.4 for 55 kVp X-rays and ~1.1-1.2 for 250 kV[subscript]p X-rays. High energy (11 MeV) electrons, on the other hand, showed a small decrease in RBE relative to ⁶⁰Co γ-rays as the dose approached zero, having a zero-dose limit of ~0.95. All of the aforementioned radiation modalities had an RBE of 1.0-1.1 at high doses (10 Gy or more). / Science, Faculty of / Physics and Astronomy, Department of / Graduate

A variation of the classical canal ray source has been developed for the study of the Stark Effect in positive ion lines. Stress was placed on the measurement of small line shifts rather than the attainment of large electric fields. To this end a sensitive shift measuring apparatus employing a linear neutral density filter to translate the line shift into a change in intensity was built. Shifts were measured to an accuracy of about .02 A° in the following lines: He I 5016 A°, 7281 A°, 6678 A°, 3889 A° and Ar I 4272 A°, 4266 A°. No shifts were detected in Ar II 4727 A° and 4806 A°. A discussion of prospective improvements to be made in the apparatus is also included. With these improvements, the apparatus should be capable of measuring shifts to an accuracy of .001 A°. / Science, Faculty of / Physics and Astronomy, Department of / Graduate

Criteria are developed for the design of an experiment to study steady radiation fronts in Cs vapor. According to these criteria, a pulsed light source of supposedly sufficient intensity (≃10²²photons/cm²-sec) and pulse length (≃90ys) was built, and an absorption tube for Cs vapor inside an oven was developed (through several models) which produced a maximum absorber density of ≃10¹⁸particles/cm³. Light and electrical probe measurements were carried out to detect ionizing radiation fronts in the cesium. While the light measurements were inconclusive due to stray light problems, the probe measurements showed that photoionization takes place but at a much lower rate than expected. A subsequent study of the light source confirmed that indeed the light source, a constricted capillary arc, driven by a 90μs square current pulse, has a much lower intensity in the test section of the absorption tube than is required to drive a front. The low intensity of this light pulse rendered the initial aim of the experiment namely the study of steady ionization fronts in cesium vapor, unattainable with the available apparatus. / Science, Faculty of / Physics and Astronomy, Department of / Graduate

It is desirable to develop tomato varieties which have the character of being able to set fruit at relatively cool temperature between 10°C to 15.5°C for commercial production in Canada. The tomato varieties Puck, Bonny Best, Immur, Prior Beta, Cold Set and some of their reciprocal Fl hybrids were grown both in greenhouses and in growth chambers under two different temperature levels, experiments were carried out to study fruit, set and the effects of self and cross-pollination on fruit development in four varieties and the Fl hybrids of PxBB, BBxP, IPBxBB, BBxIPB, CSxBB, and BBxCS. Under both cool and warm temperatures, the percentage of fruit set and also size of fruit were increased when cross-pollination was used in contrast to self-pollination. Under cool temperature, all Fl hybrid lines had a higher percentage of fruit set than their two parents, but in warm temperature the Fl hybrid lines had a intermediate percentage between those of the two parents. Under both temperature regimes there were distinct differences among lines in the time intervals for different component stages in the life cycle. Cool temperatures increased lengths of these intervals, but relative difference in lengths of interval was clearly evident. Among the ten lines, IPB was notably the earliest variety to ripe first fruit. In the first component interval from seeding to flower opening, IPB was the earliest and Bonny Best the latest; however, for the two succeeding intervals, namely flowering to fruit set and fruit set to ripening, IPB did not have the shortest intervals or most rapid growth. In fact Puck variety was better than IPB for the second component interval, and in the third interval, (BBxIPB) Fl and the reciprocal cross were the earliest. This sort of variability suggests recombination to put the earliest component stages together to synthesize a very early line. / Land and Food Systems, Faculty of / Graduate