Showing papers by "Dalhousie University published in 1968"
TL;DR: A formula is derived for the stress distribution within the myocardium which is assumed to be an isotropic, homogeneous, elastic medium, and this expression is generalized so that it is applicable for the left ventricule which is assuming as either a spherical thick shell, or an ellipsoidalshell, or a paraboloid of revolution.
204 citations
177 citations
TL;DR: In this article, the authors show that in young tectonically active continental areas there is a layer of high electrical conductivity at depths of about 20 to 40 km, and that the lower crust in these areas will have the required high conductivity if it is water saturated.
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TL;DR: In this article, the authors found that cytomegalovirus infection was sought in 16 patients before and after extracorporeal circulation during heart surgery and found that the infection was acquired during or soon after operation.
53 citations
TL;DR: The podocyst is shown to be a lamellated tanned chitin-protein complex covering the protoplasmic contents, which have a nucleated outer clear cytoplasmic layer and a yolky central zone which may be liquefied in places.
Abstract: At the junction between the scyphistoma's scyphopharynx-filament complex and its endoderm is a narrow zone of simple columnar cells. These cells can transform into amoebocytes which collect together and work their way to the aboral end of the polyp, where they secrete a cuticular encasement, thus forming the podocyst.Light and electron microscopy, as well as histochemistry, show the podocyst to be a lamellated tanned chitin-protein complex covering the protoplasmic contents, which have a nucleated outer clear cytoplasmic layer and a yolky central zone which may be liquefied in places.
53 citations
TL;DR: An investigation into the duplicability of the apex of arrow-point ~Sneedlepoint j tracings was initiated because of conflicting opinions regarding the proper position at which to occlude teeth in dentures and in reconstructed dentitions.
Abstract: A n investigation into the duplicability of the apex of arrow-point ~Sneedlepoint j tracings was initiated because of conflicting opinions regarding the proper position at which to occlude teeth in dentures and in reconstructed dentitions. Prior to 1910. dentures were constructed on articulators which were designed to imitate only the slopes of the condyles. These instruments were otherwise contrived upon various theories of mandibular motion. Followin g a series of experiments b) Gysi’ and Needles:” the concepts of the fundamentals of denture construction were greatly changed. Gysi demonstrated that a lateral path of movement which had a definite angular configuration could be shown with the use of a recording device. We designated thk angular configuration the “Gothic arch tracing.” Its apex (representing the most rctruded unstrained position of the mandible) was considered the starting point from \\,hich anterior and lateral jaw movements were made. This mandibular reference point, termed “centric relation,” has been defined as “the most rrtruded UIIstrained positional relation of the mandible to the maxillae at a given degrer, of jaw opening.” Popular opinion supports the theory that centric relation is the most important jaw relation record in treatment involving occlusion, because this point, and this point alone, can be reproduced for the purpose of establishing or ,guiding other registrations. Centric relation is a starting point.
48 citations
48 citations
TL;DR: In this paper, the reproducibility of direct scanning of thin-layer chromatograms has been investigated and it was shown that, provided the technique is rigidly standardized, relative standard deviations of 1 −5.3 % and 4 −6 % can be obtained in the case of reflectance spectroscopy, while fluorescence quenching measurements show relative standard deviation of 4 − 6 % on the same chromatogram.
TL;DR: It has been postulated that the morphogenetic switch from osteogenesis to adventitious chondrogenesis most probably involves a change in the rate of collagen and acid mucopolysaccharide synthesis by the germinal cells of the membrane bones.
Abstract: The histochemistry of the adventitious cartilage of the chick has been studied and compared with both primary cartilage and the bone on which the adventitious cartilage develops The distribution of DNA, RNA, collagen, acid mucopolysaccharide, mucoprotein, glycogen, lipid, alkaline phosphatase and inorganic phosphate has been studied Adventitious cartilage was found to have the histochemistry of primary hypertrophic cartilage and to calcify The appearance of lipid and alkaline phosphatase activity coincided with the onset of calcification
TL;DR: Two patients with hereditary spherocytosis had increased autohemolysis not corrected by supplementary glucose, while an affected son of the second patient had a typical autohemical response with glucose.
TL;DR: An adaptation of King's (1963) Piaget-type schedules was administered to 150 school children of the Hausa tribe of Northern Nigeria in eight groups drawn from very isolated rural localities, from city centres, and from areas of intermediate status, and the results strongly confirmed the expected superiority of the urban children.
Abstract: Summary. An attempt is made in this paper to measure the influence of varying types of settlement upon the attainment of scientific concepts among African school children. An adaptation of King's (1963) Piaget-type schedules was administered to 150 school children of the Hausa tribe of Northern Nigeria in eight groups drawn from very isolated rural localities, from city centres, and from areas of intermediate status. The results strongly confirmed the expected superiority of the urban children. Finally, an English version of the test was used upon a group of English school children to provide a cross-cultural comparison. The significance of the results for science education is briefly discussed.
TL;DR: Cross-layered myocytes can be seen to be another means of decreasing the surface area of the subumbrella, a condition necessary for medusoid locomotion.
Abstract: The subumbrella of the hydrozoan medusa Obelia consists of three layers of cells. The innermost layer is the endodermal lamella whose broad polygonal cells are in close contact with the middle layer of polygonal myocytes which have striated myofibrils running in two layers at right angles to one another in the same cell. These myofibrils extend beyond the myocytes as plasma membrane-enclosed prongs to make contact with the prongs of neighbouring cells in such a way that whole mounts give the impression that the slender myofibrils are continuous over the subumbrella. Cross-layered myocytes can be seen to be another means of decreasing the surface area of the subumbrella, a condition necessary for medusoid locomotion. Helically banded radial myofibrils are found in the outer layer.
TL;DR: This study was undertaken to identify the membrane changes which occurred during autohaemolysis and the effect upon these of supplementary glucose and the results confirmed the importance of knowing the carrier and removal status of canine coronavirus.
Abstract: Summary. Spontaneous autohaemolysis occurs as sterile defibrinated blood is incubated at 37°C. This study was undertaken to identify the membrane changes which occurred during autohaemolysis and the effect upon these of supplementary glucose.
After 24 hours of incubation the earliest membrane change recognized was the loss of small amounts of cholesterol; this occurred equally in incubations with and without added glucose. Spherocytes were prominent in incubations without added glucose but were infrequent when supplementary glucose was provided. During the second 24 hours of incubation cholesterol loss increased and phospholipids eluted from the cell surface. In this period of incubation cholesterol and phospholipid loss was less in incubations provided with supplementary glucose. The major individual phosphatides lecithin, sphingomyelin, phosphatidylethanolamine and phosphatidylserine were lost in proportion to their original concentration in the membrane. Membrane protein did not decrease as cell lipid loss occurred.
TL;DR: A rapid semi-quantitative method for the analysis of triazine herbicides has been developed using ultra-violet reflectance spectroscopy to evaluate the spots directly from the thin-layer chromatogram.
Abstract: Various factors affecting the fluorescence quenching properties ofs-triazines on fluorescing silicagel layers have been investigated. An analytical method has been developed which permits the quantitative analysis of these triazines, after Chromatographic separation, with an accuracy of ±5%. The instrumental detection limit for atrazine, based on a 2∶1 signal to background ratio, ranges from 0.40 to 0.25μg per spot depending on the type of silicagel used. The method compares favourably with three other techniques used for the determination of identical samples.
TL;DR: It is argued that the clear-cell type of "mesonephric" carcinoma be recognized as a separate biologic entity and called by its more proper name, "clear-cell carcinoma."
TL;DR: In this article, it has been shown that the Bay of Fundy is derived from glacial or fluvial erosion of the underlying Acadian Triassic Basin, and the recent acquisition of over 1,100 kilometers of sub-bottom profiles provides considerable data pertinent to this problem.
TL;DR: In this article, a ternary complex of benzoylphenylhydroxylamine was extracted from 10 N hydrochloric acid, which allowed the determination of 1.6 p.m. of titanium.
TL;DR: Several assumptions are usually made in seismology in the treatment of wave propagational problems in heterogeneous elastic media, and some of them are critically examined as mentioned in this paper, and some assumptions are pointed out.
Abstract: Several assumptions are usually made in seismology in the treatment of wave propagational problems in heterogeneous elastic media. These assumptions are pointed out and some of them are critically examined.
TL;DR: In this article, a scheme was devised whereby PAQH complexes of iron, nickel, copper and cobalt can be separated chromatographically and determined semiquantitatively in presence of up to tenfold excesses of interfering metal ions.
TL;DR: The lake confluence is one of the largest freshwater lakes of Central Europe and is located in south-western Germany, bordering Switzerland and Austria as discussed by the authors, with a population of around 6 million people.
Abstract: LAKE CONSTANCE is one of the largest freshwater lakes of Central Europe and is located in south-western Germany, bordering Switzerland and Austria (Fig. 1).