Showing papers by "University of Saskatchewan published in 1977"
TL;DR: In this article, a stress state variable for an unsaturated soil is proposed on the basis of writing force equilibrium equations for each phase, within the context of multiphase continuum mechanics.
Abstract: An unsaturated soil is visualized as a four-phase system, the fourth phase being the air-water interface commonly referred to as the contractile skin. Suitable stress state variables for an unsaturated soil are proposed on the basis of writing force equilibrium equations for each phase, within the context of multiphase continuum mechanics. The analysis indicates that any two of three possible normal stress variables can be used to define the stress state. Experimental null-type tests verified the proposed stress state variables for the soil structure and contractile skin of an unsaturated soil.
749 citations
TL;DR: The results suggest that glia cells are important for the uptake of glutamate from synaptic clefts and for the subsequent metabolism of glutamate.
Abstract: Uptake kinetics and contents of GABA in cultured, normal (i.e. nontransformed) glia cells obtained from the brain hemispheres of newborn mice were measured together with the activity of the GABA transaminase. During three weeks of culturing the activity of the transaminase rose from a low neonatal value toward the level in the adult brain. The uptake kinetics indicated an unsaturable component together with an uptake following Michaelis-Menten kinetics. Both theKm (40 μM) and theVmax (0.350 nmol×min−1×mg−1 cell protein) were reasonably comparable to the corresponding values in brain slices, and theVmax was much higher than that reported for other glial preparations. The GABA content was low (<5 nmol/mg cell protein), which is in agreement with the high activity of the GABA transaminase.
349 citations
TL;DR: It is shown that all the methods discussed, including Runge-Kutta, Liou's method and randomization, are closely related, but that the method of randomization is superior to the other two methods.
279 citations
TL;DR: During three weeks of culturing the activity of the transaminase rose from a low neonatal value toward the level in the adult brain, and the uptake kinetics indicated an unsaturable component together with an uptake following Michaelis-Menten kinetics.
Abstract: Uptake kinetics and contents of GABA in cultured, normal (i.e. nontransformed) glia cells obtained from the brain hemispheres of newborn mice were measured together with the activity of the GABA transaminase. During three weeks of culturing the activity of the transaminase rose from a low neonatal value toward the level in the adult brain. The uptake kinetics indicated an unsaturable component together with an uptake following Michaelis-Menten kinetics. Both theK
m (40 μM) and theV
max (0.350 nmol×min−1×mg−1 cell protein) were reasonably comparable to the corresponding values in brain slices, and theV
max was much higher than that reported for other glial preparations. The GABA content was low (<5 nmol/mg cell protein), which is in agreement with the high activity of the GABA transaminase.
179 citations
TL;DR: It is proposed that when the male transfers several spermatophores during copulation, he may make a significant contribution of protein to the developing oocytes.
149 citations
TL;DR: The findings show that the LC projection inhibits cerebral cortical neurones and implicate noradrenaline as the transmitter released by these fibres.
Abstract: 1. 1. Stimulation of the nucleus locus coeruleus (LC) inhibits the extracellularly recorded electrical activity of corticospinal and other unidentified neurones in the rat cerebral cortex. 2. 2. With 3–4 pulse trains of stimulation, the inhibitions had mean latencies of 32 ± 1.5 msec and 54 ± 2.3 msec (mean ± S.E.M.) for identified and unidentified neurones, respectively. 3. 3. The duration of LC evoked inhibition was 148 ± 4.6 msec and 148 ± 3.7 msec for the two groups of nerve cells. 4. 4. Iontophoretically applied noradrenaline depressed the spontaneous firing of all LC-inhibited cells on which it was tested. 5. 5. The LC-evoked inhibition was reversibly antagonized by MJ 1999 (Sotalol, a β-adrenergic blocker) and was absent in 6-OHDA-treated animals. 6. 6. Phenylephrine and salbutamol had depressant effects on cerebral cortical neurones. 7. 7. The findings show that the LC projection inhibits cerebral cortical neurones and implicate noradrenaline as the transmitter released by these fibres.
131 citations
119 citations
TL;DR: Measurement of the ATP and bacterial and fungal numbers in an incubated soil showed that fungal and bacterial population increases were delayed by phosphorus deficiency, indicating that ATP could be altered without major changes in the microbial populations.
Abstract: A microscopic technique utilizing dispersion of fungal hyphae in a Waring blender, filtration through membrane filters (Nucleopore Corp.), and counting on a fluorescence microscope was developed for counting fungal hyphal biomass. Nonfluorescent staining techniques of the soil-filter preparation did not give quantitative recoveries. Water-soluble aniline blue, which binds to the β-1,3-glucans of the fungal cell wall, made visualization of the hyphae by fluorescence possible. A range of fungi added to soil were quantitatively recovered. Adenosine 5′-triphosphate (ATP) was extracted from soil by lysis of the organisms with CHCl3 in NaHCO3, which prevented adsorption of the organic phosphorus to the soil colloids. Centrifugation and removal of CHCl3 was followed by dilution with pH 7.8 tris(hydroxymethyl)aminomethane buffer. ATP concentrations were measured by using the luciferase-luciferin light reaction. Since NaHCO3 interfered to some extent with this reaction, the standards were made up in equivalent mixtures of tris(hydroxymethyl)aminomethane buffer and NaHCO3. Recovery of ATP was rapid and quantitative in a range of soils. Measurement of the ATP and bacterial and fungal numbers in an incubated soil showed that fungal and bacterial population increases were delayed by phosphorus deficiency. Microbial populations were not affected at a later date. The ATP content of the soil system was reduced by phosphorus deficiency throughout the incubation period. This indicated that ATP could be altered without major changes in the microbial populations.
101 citations
TL;DR: Six areas of native grassland were labelled with 14 C during a growing season and transfers from the foliage to the roots and root respiration were measured, giving an insight into foliage dynamics and making it possible to estimate the seasonal shoot production.
Abstract: Six areas of native grassland were labelled with 14 C during a growing season. Transfers from the foliage to the roots and root respiration were measured. Plant production and turnover rates were determined by sampling the labelled material at different periods following exposure to 14 CO 2 . Above to beneath ground plant production ratios ranged between 1.1 and 1.9 with maximal translocation to the roots occurring during the drier summer months. The distribution of the photosynthates in the roots at different depths changed with time and soil moisture content. The upper part of the soil (0–10 cm) contained 49–77% of the labelled C found beneath the soil surface. Measurement of transfers with time of the above ground labelled C from living to dead plant and litter categories gave an insight into foliage dynamics and made it possible to estimate the seasonal shoot production at 130g Cm −2 (1300kg ha −1 ). Root growth represented 100g Cm −2 (1000 kg ha −1 ). Calculations of root and soil respiration were based on the CO 2 profiles in the soil. The fluxes of labelled and unlabelled CO 2 at the soil surface were estimated using the diffusion equation method. Respiration by roots and closely associated soil organisms accounted for 12 per cent of the net assimilation of CO 2 by the plants. This proportion was constant throughout the season and represented 19 per cent of the total CO 2 evolved at the soil surface.
93 citations
TL;DR: A micro-method for the identification of most acidic mucopolysaccharides by agarose gel electrophoresis with three different buffer systems with mixed results for barbital, diamine and diaminopropane buffers is described.
91 citations
TL;DR: Comparisons of equine activities including standing, walking, trotting, and getting up after the anesthetic indicate that one activity does not always produce the highest loads in all of the bones examined.
TL;DR: It is concluded that the hepatic artery is not controlled by local tissue metabolism but rather is controlled by an, as yet unknown, mechanism that tends to maintain hepatic blood flow (and therefore clearance rates) constant.
TL;DR: Superficial defects produced in rabbit articular cartilage were studied with the scanning electron microscope and it would appear that at first a new layer of matrix forms on the injured surface but that this is abraded away by joint movement so that even after 2 yr the defect does not heal.
Abstract: Superficial defects produced in rabbit articular cartilage were studied with the scanning electron microscope over a period of 2 yr. It would appear that at first a new layer of matrix forms on the injured surface but that this is abraded away by joint movement so that even after 2 yr the defect does not heal. In some instances the general articular surface developed superficial fissures, deep ravines, and foci of fibrillation.
TL;DR: Wieners supplemented with sunflower products showed low shrinkage during the smokehouse treatment and low cooking losses due to high fat and water absorptions, and Sunflower-supplemented wieners did score poorly in peelability and organoleptic tests.
Abstract: Sunflower flours and protein concentrates have potential food uses because of their high protein content, white color, bland flavor, and absence of antinutritive factors. Procedures have been developed for removal of chlorogenic acid which forms green and brown colors under alkaline pH, and selection for low chlorogenic acid cultivars is underway in plant breeding programs. Further research is needed on dehulling techniques and possible problems associated with high levels of sugars in sunflower flour. Sunflower flours and concentrates have excellent fat absorption, oil emulsification, and whipping properties. Wieners supplemented with sunflower products showed low shrinkage during the smokehouse treatment and low cooking losses due to high fat and water absorptions. Sunflower-supplemented wieners did score poorly in peelability and organoleptic tests. Sunflower proteins had an excellent amino acid balance except for low lysine content and, in feeding trials with rats, showed high protein efficiency ratios when blended with legume or meat proteins.
TL;DR: In this paper, an algorithm for finding transient solutions in Markovian queues is given and it is applied to find transient solutions for the M/M/1 queuing problem.
TL;DR: In this article, the ratio R of the intensities of anti Stokes and Stokes Raman shift lines of 124 cm -1 and of 118 cm −1 of active E. coli B was measured and it was shown that this system is excited strongly above thermal excitation.
TL;DR: In this article, the laser-Raman spectra of active bacterial cells indicate that resonances between 7 × 1010 and 5 × 1012 Hz exist in these cells, while these frequencies are not present in resting cells, of cell homogenates or of the nutrient; thus they seem to be produced as a result of active in-vivo metabolic processes.
TL;DR: In this paper, a model system for studying soil formation in semi-arid grasslands of southern Saskatchewan has been proposed based on strip mining and the construction of spoil banks composed of unweathered, clay loam textured, moderately calcareous glacial till.
TL;DR: The proposed algorithm and its modifications have been tested by obtaining load flow solutions of a five bus system, the 26 bus Saskatchewan Power Corporation transmission network model and the IEEE 14 bus, 30 bus, 57 bus and 118 bus test systems.
Abstract: This paper presents a second order load flow technique based on the Taylor series expansion of a multivariable function. An algorithm for obtaining digital solutions by the proposed approach is described. Six simplified versions of this algorithm are also discussed. The proposed algorithm and its modifications have been tested by obtaining load flow solutions of a five bus system, the 26 bus Saskatchewan Power Corporation transmission network model and the IEEE 14 bus, 30 bus, 57 bus and 118 bus test systems. The effectiveness of these algorithms is compared with the performance of the Newton Raphson approach and some of the results from these studies are presented.
TL;DR: Results indicate that clonidine cat activate histamine H2-receptors on central neurones in rats anaesthetized with a mixture of methoxyflurane, nitrous oxide and oxygen.
TL;DR: Cell wall regeneration by protoplasts from Vicia hajastana suspension cultures was investigated with Calcofluor White ST staining and platinum-palladium surface replicas and the early stages of microfibril formation could not be detected with CalCofluor staining.
Abstract: Cell wall regeneration by protoplasts fromVicia hajastana suspension cultures was investigated with Calcofluor White ST staining and platinum-palladium surface replicas. Microfibril deposition was initiated after 10–20 minutes of culture and within 20 hours protoplasts were covered with a heavy mat of microfibrils. The early stages of microfibril formation could not be detected with Calcofluor staining.
01 Jan 1977
TL;DR: An alarm pheromone (alarm substance, Schreckstoff) is released when the epidermis of an ostariophysian or gonorhynchiform fish is damaged and females respond with a fright reaction.
Abstract: An alarm pheromone (alarm substance, Schreckstoff) is released when the epidermis of an ostariophysian or gonorhynchiform fish is damaged. Conspecifics respond with a fright reaction. The alarm substance and fright reaction are both absent in some specialized ostariophysians. Others, such as blind cave fish, lose just the fright reaction. Some cyprinids, which have abrasive spawning behavior, lose the alarm substance, but not necessarily the fright reaction, during the breeding season. The development and maintenance of the alarm substance cells may be an example of animal-altruism maintained by kin selection.
TL;DR: In this paper, the authors examined whether the sensitivity of condensed and extended chromatin fractions to DNase is due to differences in protein binding to DNA or differences in the degree of chromatin condensation.
TL;DR: In this paper, the authors show that the capability of using real value-added to measure the output of a sector when material inputs are employed in the production process rests upon primary factor inputs being weakly separable from material inputs.
TL;DR: The ozone height profile in the Arctic at the end of the winter has been measured up to an altitude of 100 km using a combined solar occultation and 1.27 μ oxygen emission technique, and it is suggested that this reduced ozone concentration may have been associated with a stratospheric warming event that was in progress at the time of the measurement as discussed by the authors.
TL;DR: The observations suggest that the immunoelectrophoresis test based on arc 5 positivity is not E. granulosus-specific as originally described.
Abstract: The Echinococcus granulosus diagnostic arc 5 was revealed by sera from an Alaskan and a Swiss patient with surgically confirmed E. multilocularis infections. The possibility of each patient harboring a concurrent infection with both parasites may be disregarded on the basis of radiologic, scintillographic and surgical data. This conclusion is compatible with ecologic and epidemiologic considerations. These observations suggest that the immunoelectrophoresis test based on arc 5 positivity is not E. granulosus-specific as originally described.
TL;DR: In this article, the authors describe some fundamental stage combinations that can be used to simulate a wide range of distributions, and refer to more-extensive explanations, such as more extensive explanations for more complex transition rates.
Abstract: Several techniques are available for solving reliability models containing non-exponential state residence times. All of these techniques, other than the method of stages, involve derivation of closed-fonn expressions in time domain or Laplace form. Though the closed-form solutions are useful, they are often impossible to derive due to complexity of the interstate transition rates. Stage combinations can be used either to fit the available data or approximate a known probability distribution. The main advantage with this method is that though an explicit mathematical expression does not emerge, the numerical solution can be generally obtained. This paper briefly describes some fundamental stage combinations that can be used to simulate a wide range of distributions, and refers to more-extensive explanations.