Showing papers by "Dalhousie University published in 1974"
306 citations
TL;DR: This article showed that linolenic acid in deodorized vegetable oils is accompanied by two major artifacts identified as cis-9,cis-12,trans-15 and trans-9-cis 12, trans-15 isomers, which were not present in unrefined oils or bleached oils but could be induced by deodorization in the laboratory.
Abstract: Gas liquid chromatography on polar open tubular columns of the methyl esters of fatty acids from vegetable oils shows that the linolenic acid in deodorized oils is accompanied by two major artifacts identified as cis-9,cis-12,trans-15 and trans-9,cis-12,cis-15 isomers. Physicochemical studies, isolation, and partial degradation steps showed two additional isomers with trans-9,cis-12,trans-15 and cis-9,trans-12,cis-15 structures. Gas liquid chromatography also showed that linoleic acid was accompanied by the trans-9,cis-12 isomer. These artifacts were not present in unrefined oils or bleached oils but could be induced by deodorization in the laboratory. Proportions of the two major artifacts in total 18:3ω3 are given for some vegetable oils from the retail market.
168 citations
TL;DR: Results suggest that electrical stimulation of cortical slices which had been incubated with 3H‐choline causes the release of only [3H]‐ACh, both in the presence or absence of an anticholinesterase.
Abstract: 1 In order to establish the origin of the increased efflux of radioactivity caused by electrical stimulation of cerebral cortical slices which had been incubated with [3H]-choline, labelled choline and acetylcholine (ACh) collected by superfusion were separated by gold precipitation.
2 In the presence of physostigmine electrical stimulation (1 Hz, 10 min) increased the release of only [3H]-ACh which was greatly enhanced by the addition of atropine.
3 Continuous stimulation in the presence of physostigmine resulted in an evoked release of [3H]-ACh which declined asymptotically. This evoked release appeared to follow first-order kinetics with a rate constant which remained stable over the course of prolonged stimulation.
4 The rate constant for the evoked release of [3H]-ACh with 1 Hz stimulation was three times greater in the presence of physostigmine and atropine than in the presence of physostigmine alone, while the size of the store from which [3H]-ACh was released was nearly identical under these two conditions.
5 In the absence of physostigmine and atropine, stimulation caused the appearance of only [3H]-choline in the samples.
6 Reduction of [3H]-ACh stores before the application of physostigmine resulted in a reduced evoked release of total radioactivity, both in the absence or presence of physostigmine and atropine, and decreased the evoked release of [3H]-ACh without affecting the release of [3H]-choline.
7 Results suggest that electrical stimulation of cortical slices which had been incubated with [3H]-choline causes the release of only [3H]-ACh, both in the presence or absence of an anticholinesterase. The evoked increase in the efflux of total radioactivity is therefore a good measure of the release of [3H]-ACh.
143 citations
TL;DR: The effects of publicly marking attendance at practice as a sufficient solution for reducing absenteeism, tardiness, and leaving early and the effects of employing program boards as a means of increasing work output during practice were verified.
Abstract: Swimmers' attendance at training and work rates were described by their coaches as being poor and irregular. Reinforcement contingencies were developed to remedy these unsatisfactory conditions. Two experiments were conducted. A multiple baseline design verified the effects of publicly marking attendance at practice as a sufficient solution for reducing absenteeism, tardiness, and leaving early. Follow-up analyses showed this contingency to have lasting effects. In the second experiment, a reversal design was used to assess the effects of employing program boards as a means of increasing work output during practice. Work rates in eight selected swimmers were elevated by an average of 27.1% when the boards were instituted. Follow-up evaluations showed that the use of the program boards had lasting effects. Publicly checking the completion of each training unit of work changed the nature of the swimming environment to produce a more productive use of time. The role of the coach was subsequently changed as less time was spent in directing and supervising behaviors.
134 citations
TL;DR: Immunohistological study of lung biopsies from four palients with farmer's lung revealed histological evidence of vasculilis along with deposits of immunoglobulins and C3 in and around the affected vessels in the biopsie from two palients.
Abstract: Summary
Immunohistological study of lung biopsies from four palients with farmer's lung revealed histological evidence of vasculilis along with deposits of immunoglobulins and C3 in and around the affected vessels in the biopsies from two palients. Both these patients were exposed to mouldy hay antigens shortly before biopsy. Both these patients also had considerable numbers of eosinophils in their lung lesions. Immune-complex mediated vasculitis is probably an early event in the pathogenesis of farmer's lung and might not be detectable in the absence of recent exposure to relevant antigens. The presence of large numbers of eosinophits in these lesions suggests a type I reaction acting as the trigger for a type 3 reaction.
117 citations
TL;DR: Blood plasma collected from chick embryos and from 2-day-old chicks was deproteinized, extracted, and the steroid hormones separated by column chromatography determined using the competitive protein-binding globulin method of Murphy (1967).
115 citations
97 citations
TL;DR: In this paper, the main supply of food for deep-sea plankton is conveyed from the euphotic zone by overlapping vertical migratory plankters, which sinks passively in the ocean.
Abstract: The question of how organisms living below 1000 metres depth in the oceans obtain food in sufficient quantity to survive has lately received a lot of attention (Vinogradov, 1968; Sanders & Hessler, 1969; Fournier, 1972). The oldest and simplest theory, first advocated by Agassiz (1888), is that deep-sea organisms are nourished by a ‘rain’ of organic detritus from overlying surface waters. Detritus is defined to include all organic particles, living and dead, which sink passively. An alternate proposal by Riley (1951), Vinogradov (1962) and Wickstead (1962) is that the main supply of food for deep-sea plankton is conveyed from the euphotic zone by overlapping vertical migratory plankters.
95 citations
TL;DR: In this paper, a method for choosing (post hoc) a set of v1 mutually orthogonal null contrasts such that the maximum number (r) rejectable by a new criterion are rejected and v1 − r retained is given.
Abstract: A method is given for choosing (post hoc) a set of v1 mutually orthogonal null contrasts such that the maximum number (r) rejectable by a new criterion are rejected and v1 – r retained. Type I error rate is defined as the expected proportion of the v1 decisions which will be errors when all nulls are true. Because the new criterion uses F, the expected proportion of rejections can be calculated for the case when all nulls are not true, and this is taken as the definition of power. Theoretical means are deducible from decisions for v1 mutually orthogonal contrasts and, if rejected null contrasts are given suitable non-zero values, there is no ambiguity about the theoretical means. The traditional values of FΓ; v1, v2 ‘load the dice’ against finding true interactions ‘significant’ in factorial analyses. The new values (table given) do not have this property and their use is illustrated using a one-way anova on data from a factorially designed experiment. This procedure permits the analysis of unequal replications in factorially designed experiments.
91 citations
TL;DR: Because of their low volatility, their chemical stability, and lipid solubility, PCBs have been detected in eco-systems, showing biological magnification as one examines residues in food chains.
85 citations
TL;DR: Results suggest that under physiological conditions, i.e. in the absence of an anticholinesterase, the release of ACh per stimulus decreases with increasing frequency of stimulation and that this decrease is due to a lag in the mobilization of stored ACh rather than in the synthesis of new ACh.
Abstract: 1 The release of endogenous acetylcholine (ACh) from cerebral cortical slices stimulated at 0.25, 1, 4, 16 and 64 Hz was measured in the presence either of physostigmine or of physostigmine and atropine.
2 Atropine potentiated the evoked release of endogenous ACh especially at low frequencies resulting in an output per stimulus which sharply declined with increasing frequency of stimulation, while in the absence of atropine the output of ACh per stimulus was low and fairly constant.
3 The evoked release of [3H]-ACh per stimulus following the incubation of the slices with [3H]-choline, as estimated by means of rate constants of the evoked release of total radioactivity, showed a frequency dependence similar to endogenous ACh when the two were tested under identical conditions.
4 In the absence of an anticholinesterase the evoked release of [3H]-ACh per stimulus was dependent on frequency of stimulation in a similar way to that in the presence of physostigmine and atropine.
5 Results suggest that under physiological conditions, i.e. in the absence of an anti-cholinesterase, the release of ACh per stimulus decreases with increasing frequency of stimulation and that this decrease is due to a lag in the mobilization of stored ACh rather than in the synthesis of new ACh.
TL;DR: A theory of weak stability for linear multistep methods for the numerical solution of Volterra integro-differential equations is developed, and a connection between this theory and the corresponding theory for ordinary differential equations is established.
Abstract: A theory of weak stability for linear multistep methods for the numerical solution of Volterra integro-differential equations is developed, and a connection between this theory and the corresponding theory for ordinary differential equations is established. In addition, the order of such methods is discussed, and a new starting procedure is proposed and analyzed.
TL;DR: Clinal differentiation of stipe traits in Laminaria (simplices) populations occurs on a gradient of exposure to wave action, and quantitative genetic analysis of the degree of resemblance between relatives indicated a relatively high genetic component in the interpopulation differentiation.
Abstract: Clinal differentiation of stipe traits in Laminaria (simplices) populations occurs on a gradient of exposure to wave action. Crossability tests and the production of fertile hybrids established interfertility between populations from the extremes of the morphological range. Reciprocal transplantation experiments between exposed and sheltered sites did not produce significant changes in stipe morphology. Quantitative genetic analysis of the degree of resemblance between relatives indicated a relatively high genetic component in the interpopulation differentiation. This is consistent with the results of the transplantation experiments. Within-population heritability estimates at the exposed site were low, perhaps because of intensive local stabilising selection which acts to reduce genetic variability. The question of conspecificity of L. saccharina and L. longicruris in view of these results is discussed.
TL;DR: Cases of non-specific encephalopathy and fatty visceral changes in children living in the vicinity of forest-spraying operations stimulated this work in mice, and the possible role of exposure to combinations of insecticides in human viral susceptibility requires further attention.
TL;DR: In this article, stepwise outgassing experiments were performed on eleven whole rock samples from a sequence of diabase dikes from the Great Northern Peninsula, and it was shown that plagioclase is dominating the age spectra in this temperature interval.
TL;DR: The architecture and function of the lophophore of the marine bryozoan Cryptosula pallasiana (Moll) are described, including some new features not previously discovered in bryozoans.
Abstract: The architecture and function of the lophophore of the marine bryozoan Cryptosula pallasiana (Moll) are described, including some new features not previously discovered in bryozoans. The nature of fluid movements within the lophophoral coelom during feeding activities is postulated on the basis of the arrangements of epithelia and muscles. Epithelial cells at the tentacle bases are blastemic in nature, and there is a ciliated pit of unknown function in the angle between every pair of tentacles. There are 6 nerves in each tentacle, including a pair of single-axon subperitoneal nerves. Neurosecretory-like vesicles and glycogen occur in some neurons of the ganglion. The basal lamina collagen has a diameter smaller than that previously recorded for an invertebrate. Filament dimensions are given for several different muscles. Tentacle muscles and lophophore retractor muscles are smooth. Thick paramyosin-like filaments up to 75 nm diameter occur in two muscle types. A new set of muscles is described: the basal transverse muscles of the tentacles.
TL;DR: Biphenyl and all the Aroclors caused the same degree of enhancement of BSP-GSH conjugating enzyme and p -nitrophenol UDPglucuronyl transferase activities were measured in young Wistar male rats which had received intraperitoneal injections.
TL;DR: A deep borehole on Sao Miguel encountered temperatures exceeding 200°C at a depth of 550 m as discussed by the authors, indicating an average subsidence of 0.1 cm yr−1 for the island over the past 690,000 Myr.
Abstract: A deep borehole on Sao Miguel encountered temperatures exceeding 200° C at a depth of 550 m. Subaerial volcanics persist to a depth of 786 m below sea level and indicate an average subsidence of 0.1 cm yr−1 for the island over the past 690,000 Myr.
TL;DR: In this article, a simple physical interpretation for hyperfine fields systematics at the sites of nonmagnetic ions in concentrated ferromagnetic alloys is given and applied to Heusler alloys and numerical results are given.
TL;DR: Das Modell wurde an zwei Regelvorgängen im menschlichen Körper überprüft — Regulierung of Korkorpertemperatur and Blutdruck and das Filter besteht aus einem Rückkopplungszweig, einem Ein-/Ausschalt-element and einem frequenzabhängigen Teil.
Abstract: Es wird allgemein angenommen, das biologische Rhythmen eine Rolle als Zeitgeber fur Systeme spielen. Zirkadische Rhythmen z.B. stellen die Beziehung zwischen dem hell-dunkel Zyklus der Umwelt und dem zeitlichen Ablauf interner Vorgange her. Schnellere Rhythmen sind wahrscheinlich auf Ein-/Ausschaltungen homeostatischer Regler zuruckzufuhren. Das hier beschriebene Modell besteht aus einem Ruckkopplungszweig, einem Ein-/Ausschalt-element und einem frequenzabhangigen Teil (Filter). Es reproduziert die wichtigsten Eigenschaften des lebenden Originals — exakte Regulierung, amplituden begrenzte spontane Schwingungen (Rhythmen) und das Synchronisieren dieser Schwingungen durch ausere periodische Storungen, die eine von der Frequenz abhangige Mindestamplitude uberschreiten.
TL;DR: There is evidence that a number of drugs which have profound effects on the central nervous system (CNS) may do so by altering membrane bound (Na++K+)-dependent ATPase and/or Na+ pump activities.
Abstract: THERE is evidence that a number of drugs which have profound effects on the central nervous system (CNS) may do so by altering membrane bound (Na++K+)-dependent ATPase and/or Na+ pump activities. For example, ouabain which is an inhibitor of neuronal (Na++K+) dependent ATPase1 and Na+ pump activity2, can impair short term memory in small doses3 and produce convulsions when larger doses are administered intraventricularly4.
TL;DR: The degree of ultrastructural alteration appeared to be related directly to the number of chlorine atoms and the presence of chlorine in the 4- or 4′-position.
TL;DR: Replicate sampling for particulate organic carbon (POC) in the open ocean indicates that at any given position and depth the POC distribution consists of a homogeneous background concentration on which are superimposed occasional small patches containing two to five times as much organic carbon as is present in the background as discussed by the authors.
Abstract: Replicate sampling for particulate organic carbon (POC) in the open ocean indicates that at any given position and depth the POC distribution consists of a homogeneous background concentration on which are superimposed occasional small patches containing two to five times as much organic carbon as is present in the background. The 95% confidence limits for a single 5-liter sample taken solely from the background are ±2.5 µg C liter−1. The size and frequency of the patches may determine the distribution and productivity of the smaller zooplankton.
TL;DR: 7α-Hydroxysteroid dehydrogenase activity was found in 24 of 25 strains of E. coli and was shown to be useful for quantifying 7α-OH-containing bile acids, particularly the glycine and taurine dihydroxy conjugates.
TL;DR: A mutant (strain 704) of the obligate photoautotroph Anacystis nidulans is described which behaves like the wild type under continuous illumination but which in the dark rapidly loses viability, respires little, and incorporates label into ribonucleic acid and protein at rates considerably less than observed with the darkened wild type.
Abstract: We describe a mutant (strain 704) of the obligate photoautotroph Anacystis nidulans which behaves like the wild type under continuous illumination but which in the dark rapidly loses viability, respires little, and incorporates label into ribonucleic acid and protein at rates considerably less than observed with the darkened wild type. Extracts of this mutant strain show no detectable 6-phosphogluconate dehydrogenase (EC 1.1.1.44) activity. Spontaneous revertants of mutant 704 were selected as survivors of prolonged incubation in darkness. Of 10 such strains examined, none had regained 6-phosphogluconate dehydrogenase activity, and all had lost detectable glucose-6-phosphate dehydrogenase (EC 1.1.1.49) activity. Although dark survival of these revertants paralleled that of the wild type, rates of dark endogenous respiration and incorporation of labeled precursors into ribonucleic acid were still very low, comparable to those observed with strain 704. These results are consistent with the following hypotheses concerning dark endogenous metabolism in unicellular blue-green bacteria. (i) Although the oxidative pentose phosphate cycle (hexose monophosphate shunt) may play a major role in endogenous metabolism in A. nidulans, as proposed by others, it is not the only pathway capable of providing energy for maintenance of viability in darkness. (ii) Much of the endogenous metabolic activity (respiration and macromolecular synthesis) observed in darkened cultures of wild-type A. nidulans is not required for survival alone, and must therefore serve other functions.
TL;DR: The solubility of amorphous silica in seawater at 0°C and from 1 to 1,220 atm. was found to be a linear function of pressure above 270 atm, but to deviate from linearity below that pressure.
TL;DR: A cell-surface localizing heterologous antibody against the mouse EL4 lymphoma could be bound to varying amounts of 131 I without interfering with the reactivity of the antibody with EL4 cells.
TL;DR: Immunohistochemical examination of pulmonary sarcoid lesions from three patients revealed in all the presence of clumps of immunoglobulin and complement in those granulomas which were not completely fibrosed, which supports the contention that the lesions of Sarcoidosis might have an immunologic basis.