Showing papers by "University of Calgary published in 1980"

Lipid peroxidation associated with accelerated aging of soybean axes.

Abstract: Soybean seeds age rapidly during storage at high temperature and high relative humidity. The axes of such aged seeds contain high levels of malondialdehyde, a product of the peroxidation of unsaturated fatty acids. The levels of linoleic (18:2) and linolenic (18:3) acids in a polar lipid (phospholipid) fraction decrease during aging and more dramatically during postaging deterioration. None of these changes occurred in seeds that have been stored at high temperature but low relative humidity. No superoxide dismutase activity was detected in any nonimbibed seed. In viable seeds, activity was detectable 1.5 hours after the onset of imbibition, but none was found in aged seeds up to 5 hours. It is suggested that aging leads to peroxidative changes to lipids and that these could contribute to loss of viability.

The calculation of critical points

Abstract: Chemical engineers have taken a new look at the critical-point mathematics for multicomponent hydrocarbon mixtures and have found an alternative way to evaluate the two nonlinear functions of the intensive variables in the critical phase; the procedure greatly facilitates the computations involved, allowing applications to very large systems (with up to 43 components) and to systems with high-density (liquid-liquid) critical points. The calculation procedure is robust and converges (in all the cases studied so far) in three to five iterations.

Sedimentation in anastomosed river systems; examples from alluvial valleys near Banff, Alberta

Abstract: Three anastomosed river systems are described. Each reach consists of an interconnected network of low-slope, narrow and deep, straight to sinuous, stable channels that transport coarse sand and gravel. Channels are separated by levees and wetlands composed of silt/mud and vegetation. Gravel-bed braided channels occur upstream from each anastomosed system, joined by a transitional reach comprising stable, elongate, silt islands within braided channels. The three anastomosed reaches have formed upstream from elevating base levels caused by deposition of alluvial fans across trunk valleys. Rapid aggradation of floodplain alluvium is confirmed by buried volcanic ash layers. Channel migration is inhibited by root-stabilized banks which, combined with rapid vertical aggradation, results in production of stringer-like, coarse-grained channel deposits surrounded by overbank fines in stratigraphic cross sections. Although it is unlikely that such small base-level controls (alluvial fans) could produce extensive anastomosed deposits, other mechanisms such as glacial moraines, isostatic rebound, or marine transgressions could provide plausible controls for yielding important contributions to the stratigraphic record.

A case-control study of diet and colo-rectal cancer.

Abstract: A case-control study of cancer of the colon and rectum has been conducted in Calgary, Alberta and Toronto, Ontario, Canada. A total of 348 cases of cancer of the colon and 194 cases of cancer of the rectum were individually matched by age, sex and neighbourhood of residence to 542 population controls and frequency matched to 535 hospital controls who had undergone an abdominal operation. Each subject received a personal medical history questionnaire and a quantitative diet history questionnaire. Data on a number of potential non-nutrient risk factors for bowel cancer and on the consumption of 9 nutrients in the 2-month period up to 6 months before interview were analysed. The dietary data thus refer to recent diet consumed in a period antedating the diagnosis of, and in most cases symptoms from, large-bowel cancer in the cases, and a corresponding time period in the controls. The major findings were an elevated risk for those with a history of bowel polyps, and for those with an elevated intake of calories, total fat, total protein, saturated fat, oleic acid and cholesterol. No association was seen with an elevated intake of crude fibre, Vitamin C and linoleic acid. The nutrients for which an increased risk was demonstrated were highly correlated, though multivariate analysis using logistic regression indicated highest risk for saturated fat, with evidence of a dose-response relationship. The findings in both cancer sites, both sexes and with both sets of controls were quantitatively very similar. The population-attributable risk for colon and rectal cancer combined was estimated from the neighbourhood controls to be 41% for males and 44% for females for saturated fat intake and 9.8% and 6.4% respectively for any history of polyps.

Release of somatomedin-like activity by cultured WI-38 human fibroblasts.

Abstract: Confluent cultures of normal diploid WI-38 human embryonic lung fibroblasts released somatomedin (SM)-like activity into their incubation medium during culture in serum-free medium. This postculture medium (conditioned medium) stimulated cell division in these same cultured WI-38 fibroblasts and 35SO4 uptake by hypophysectomized rat cartilage in vitro. The conditioned medium also contained immunoreactive SM (IRSM) activity which yielded parallel dose-response curves to human serum in a RIA for SM. The IRSM activity measured in conditioned medium was not the artifactual result of effects of possible SM-binding proteins or proteolytic enzymes in conditioned medium. These studies suggest that cultured WI-38 fibroblasts produce and release SM-like activity which has SM-like biological activity and is immunoreactive with a basic SM purified from human plasma Cohn fraction and having similarity with SM-C and insulin-like growth factor-I. Human GH appears to stimulate production and release of IRSM activity by these cells.

Shifts in carbon isotope ratios of two C3 halophytes under natural and artificial conditions.

Abstract: The total carbon δ13C values of two C3 halophytes,Salicornia europaea L. ssp.rubra (Nels.) Breitung andPuccinellia muttalliana (Schultes) Hitch., native to inland saline areas of Alberta, Canada, were determined for plants grown under controlled conditions of supplied NaCl in the nutrient solution, and for plants found growing in the field. Field specimens were collected along line transects which ran from areas of high salinity to areas of low salinity across the pattern of species zonation. The δ13C value of the two species seemed to reflect the water potential of the soil (ψ w soil ) as measured arbitrarily at a depth of 10 cm, becoming less negative as the ψ w soil decreased. Over a linear distance of 5.55 m,S. europaea spp.rubra showed a shift of +5.3‰ as the ψ w soil went from-25x102 kPa to a minimum of-73x102 kPa. ForP. nuttalliana, the δ13C values differed by 3.4‰ over a distance of 7.45 m where the maximum difference in ψ w soil was 12.7x102 kPa. However, δ13C values ofP. nuttalliana only roughly reflected the spatial trends in ψ w soil at the time of collection. In the growth chamber, the δ13C value ofS. europaea ssp.rubra changed by a maximum of +8.0‰ when the solute potential of the nutrient solution (ψ w soil ) was dropped from-0.25x102 kPa to-64.25x102 kPa; while the δ13C value ofP. nuttalliana changed by a maximum of +10.8‰ when the ψ w soil was dropped from-0.25x102 kPa to-40.25x102 kPa. Linear regression analyses indicated that the δ13C values of both species were strongly correlated (P<0.2%) with ψ w soil . The observed shifts in δ12C may represent changes in the mode of photosynthetic CO2 fixation. However, a number of other explanations, some of which are discussed in the text, are also possible. A proper ecophysiological interpretation of such shifts in δ13C values of C3 plants awaits a better understanding of the isotope fractionation mechanisms involved.

The Use of Capacitance Sensors for Phase Percentage Determination in Multiphase Pipelines

Abstract: A variety of capacitance designs are considered for determining the volume fractions in two-phase pipelines. Experimental results are compared for the most promising structures and for slug (SL) and stratified (ST) flow patterns. It is concluded that the most practical linear sensor is the double helix capacitance, although in some instances a four concave-plate structure may be preferred for greater sensitivity and simplicity of construction if the flow pattern is known.

Sequence of events in the digestion of fresh legume leaves by rumen bacteria.

Abstract: When fresh whole leaves of six different species of forage legumes were suspended in an artificial rumen medium and inoculated with rumen bacteria, bacterial adhesion and proliferation were noted at the stomata, and penetration of the stomate by these bacteria was documented by electron microscopy. The invading bacteria adhered to surfaces within the intercellular space of the leaf and produced very extensive exopolysaccharide-enclosed microcolonies. After some of the legume leaf cell walls were disorganized and ruptured by bacterial digestion, these cells (notably, parenchyma and epidermal cells) were invaded by bacteria, with subsequent formation of intracellular microcolonies. However, other cells were neither ruptured nor colonized (notably, stomata guard cells and vascular tissue). At all stages of the digestion of intact legume leaves, the rumen bacteria grew in microcolonies composed of cells of single or mixed morphological types, and a particular ecological niche was often completely and consistently occupied by a very large microcolony of cells of single or mixed morphological types. Images

Existence and uniqueness theorems for the algebraic Riccati equation

Abstract: Necessary and sufficient conditions for existence and uniqueness of hermitian solutions of the algebraic n×n matrix Riccati equation (D≥0,C∗=C,(A, D) controllable) are obtained. The conditions are formulated in terms of the spectral structure of a certain 2n × 2n matrix. A description is also given of the set of solutions in a geometrical language of invariant subspaces which are neutral with respect to a certain indefinite scalar product. This technique is then applied to provide some results on existence and uniqueness of solutions which are not necessarily hermitian. The problem is also approached (when Dz;> 0)via a related unilateral equation. for Z where K1 ∗ equals K1, K0 ∗ equals K0

Proteins in cerebrospinal fluid and plasma of fetal sheep during development.

Abstract: 1. The concentration of total protein in c.s.f. and plasma has been measured in fetal sheep of different gestational ages and in the adult. In c.s.f. it was highest (approximately 840 mg/100 ml.) in the youngest fetuses (35 days) and declined steeply by 60 days (260 mg/100 ml.). It decreased less markedly in the last half of gestation to reach about 50 mg/100 ml. at 125 days which is twice the adult value. Protein concentration in plasma was lowest in the youngest fetuses and did not rise much until the second half of gestation during which time it doubled. There was a further rather larger increase between the late fetal (125 days) stage and the adult.2. Albumin, fetuin, alpha-fetoprotein (AFP), transferrin and lipoprotein were identified in c.s.f. and plasma.3. The concentrations of albumin, AFP and fetuin in c.s.f. and plasma at different gestational ages were measured using immunodiffusion and radioimmuno-assays.4. Albumin was the major protein in plasma at all ages studied (35-128 days gestation and adult). Its concentration increased throughout gestation whereas that of fetuin was similar at all fetal ages and that of AFP declined markedly during the second half of gestation. In the adult, fetuin was only about 0.1% of the total protein in plasma and AFP was not detectable.5. In 35-40 day fetuses albumin, AFP and fetuin accounted for 90% of the total protein concentration in plasma and for about 70-80% of the total protein concentration of c.s.f. As gestation progressed the concentration of all three proteins in c.s.f. declined. But the concentration of AFP and fetuin fell more rapidly and to a greater extent than that of albumin; neither AFP nor fetuin could be detected in adult c.s.f.6. The c.s.f.: Plasma ratio was above 50% for AFP and above 60% for fetuin at 35 days compared with about 25% for albumin at the same fetal age. The c.s.f.: plasma ratios for all three proteins declined with increasing fetal age and were not significantly different from each other by about mid gestation.

Evidence of prostaglandin involvement in blastocyst implantation.

Abstract: Delayed-implantation mice were used to test for local implantation induction effects of prostaglandins E2 and F2α Evidence of implantation was gathered by microdissection of implantation sites and by scanning electron microscopy. Indomethacin was tested for the ability to interfere with the mechanisms of estrogen-induced, normal implantation. Both prostaglandins appear to have significant effect inducing implantation when applied locally in the uterine lumen, PGE2 being more effective than PGF2α. The indomethacin clearly has a blocking effect on normal implantation. However, indomethacin appears only partially able to prevent the morphological changes indicative of the trophoblast cell transformation.

Nature and Control of Shale Basin Fill and its Effect on Reef Growth and Termination: Upper Devonian Duvernay and Ireton Formations of Alberta, Canada

Abstract: Within basin-filling shales of the Frasnian Duvernay and Ireton Formations a number of inclined electric log markers indicate the presence of significant submarine topography during deposition. Log markers reflect submarine hardgrounds on the platform and in the basin, and may be traced laterally into thin carbonate-rich layers on the slope. Markers formed in response to a relaxation in terrigenous sedimentation against a background of continuous carbonate deposition, and may be considered essentially synchronous surfaces. The presence of synchronous stratigraphic markers allows precise quantitative depth estimates of lithofacies and biofacies ranges to be made. Log markers may be used to divide the Duvernay and Ireton Formations into a total seven informal chronostratigraphic units termed depo-units. Depo-units are broadly sigmoidal in cross section and imbricated basinward, their platform portions forming a stacked sequence of upward-shoaling units in the east of the basin. They indicate that deposition took place during a number of episodic rises in sea level, each of the order of 20 m. A reciprocal pattern of sedimentation involving rise and stillstand characterizes and explains depositional patterns in this stratigraphic interval. Mapping of the upper surfaces of individual depo-units allows the paleogeography to be reconstructed at a number of stages during basin-filling. Formation of log markers and depositional episodes in basin-filling shales have been used to explain growth stages and eventual termination of hydrocarbon-producing Leduc reef buildups within and surrounding the Shale Basin.

A uniqueness theorem and a variational principle for generalized thermoelasticity

Abstract: A uniqueness theorem is obtained for the equations of generalized linear thermoelasticity formulated by Lord and Shulman for a homogeneous isotropic body. A variational principle for the equations of motion is derived.

Attributions of Success and Failure Comparison of Cultural Differences between Asian and Caucasian Children

Abstract: Using children from Canadian Caucasian and Asian Indian populations, the hypothesis was assessed that Asian children would attribute both success and failure in achievement tasks, to stable factors of ability and effort By contrast, the prediction was that Caucasian children would asume personal responsibility only for success but would attribute failure to unstable factors of luck, task difficulty, and inaccuracy of the evaluator The rationale employed was that socialization training in certain cultures provides impetus for assuming personal responsibility for both negative and positive outcomes Ss were given two performance tasks with success and failure outcomes, under conditions of high and low ego involvement As hypothesized, Caucasian Ss took greater personal credit for success and attributed failure to luck, but Asian Ss assumed more personal responsibility for failure and attributed success to luck The implications of the attributional patterns were discussed in terms of the socialization of

Changes of Endogenous Gibberellin-like Substances with Sex Reversal of the Apical Inflorescence of Corn.

Abstract: In developing apical meristems of corn, the level of acidic, ethyl acetate-soluble gibberellin (GA)-like substances increased to a maximum of 108 micrograms GA(3)-equivalents per kilogram dry weight of tissue at inflorescence initiation, and then fell rapidly. At anthesis, only a trace (0.2 microgram per kilogram) of GA-like activity remained in the apical (male) inflorescences, whereas moderate activity (32 micrograms per kilogram), mostly of a nonpolar nature, was present in lateral, female, inflorescences.A sex reversal of the apical inflorescence, from male to female, was elicited by reducing the ambient light intensity. Higher levels of GA-like substances, particularly those eluting from a SiO(2) partition column in the nonpolar region, were observed at all harvests in the reverting meristems; levels increased to 180 micrograms per kilogram at inflorescence initiation, then dropped to 122 micrograms per kilogram in the apical (female), reverted meristems. This increase in endogenous GA-like activity with reversion to the female inflorescence is consistent with observations that (a) reversion can be obtained with exogenous application of GA(3) and (b) maleness is enhanced in GA-deficient mutants of maize. Endogenous GAs may thus play a key role in the control of sexuality of corn.

Changes in the composition of labeled protein transported in motor axons during their regeneration.

Abstract: Labeled proteins transported in rat sciatic nerve axons after application of L-(35S) methionine to motoneuron cell bodies were characterized by SDS0poly-acrylamide gel electrophoresis. During nerve regeneration following a crush injury, changes were observed in the composition of the fast-transported proteins. The major change was an increase in relative amount of a 18,000-dalton poly-peptide (S2). Less dramatic changes occurred in a 66,000-dalton polypeptide (N) which also increased, and in a 13,000-dalton polypeptide (T) which decreased. The increase in S2 and N was significant by three days after injury and all changes were maximal between 7 and 14 days. A return to normal proportions was reached between 21 and 42 days. It is concluded that axonal injury produces, among its other effects, an alteration in the proportions of proteins transported into the axon. It remains to be determined whether these changes are prerequisites for axonal regeneration, or facilitate regeneration, or are incidental to it.