Showing papers by "University of Ottawa published in 1972"
TL;DR: In this article, the authors studied the Donjek, a proglacial braided river with a coarse heterogeneous bedload ranging from −7 to +8 φ.
Abstract: The Donjek is a proglacial braided river with a coarse heterogeneous bedload ranging from −7 to +8 φ. The three reaches studied comprise, in downstream order, a zig-zag reach formed by the interaction of the river and tributary fans, a straight reach, and a meandering reach, all with internal braids. The straight to meandering junction is unusual in that slope and discharge both increase.
The dominant bed-forms are longitudinal gravel bars, which migrate only during flood. Their internal structure is poorly defined horizontal bedding, which suggests that gravel deposition takes place on the upper bar surfaces, rather than on foreset slopes at the downstream margins. At lower stage sand accumulates in wedge-shaped units lateral to the bars, with internal high-angle cross-stratification and ripple cross-lamination; other sedimentary structures are rare. A simple facies model can be constructed on the basis of two trends: a proximal-distal trend, and an active-stable trend. Both result in the increased abundance of fine-grained sediment.
Random directional measurements give good estimates of the river trend from small-scale structures (mainly ripples) and from channels, the latter giving the closest approximation. The variability of ripple orientation always exceeds that of channels. Both increase in the meandering reach, although the divergence of the vector mean from the river trend is not significantly greater than in the straight reach.
307 citations
160 citations
TL;DR: The amygdaloid complex in the cat was studied in a series of Golgi preparations and the dendrites of neurons in the medial part of the central nucleus, the medial nucleus and the anterior amygdAloid area undergo less branching and carry fewer spines than those of the type P cell.
Abstract: The amygdaloid complex in the cat was studied in a series of Golgi preparations. Both the lateral and the basal nucleus are composed of the same two cell types, one of which (type P) resembles the pyramidal and the other (type S) the stellate neuron of the cortex. The cortical nucleus can be divided into three layers (I, II, and III–IV) which are made up of cells similar to those in the periamygdaloid cortex. In addition, there are sufficient differences in the organization of these layers to justify a subdivision of the cortical nucleus into lateral and medial parts. The dendrites of neurons in the medial part of the central nucleus, the medial nucleus and the anterior amygdaloid area undergo less branching and carry fewer spines than those of the type P cell. The neurons in the nucleus of the lateral olfactory tract are all of the pyramidal or modified pyramidal type. These findings are discussed in relation to those of previous investigators who employed the Nissl and Golgi methods.
118 citations
TL;DR: It is indicated that cyclophosphamide is only minimally effective in the treatment of lung cancer, but it is an active drug and it should be considered for inclusion in future trials of drug combinations.
Abstract: Patients with non‐resectable lung cancer confined to the central area of the thorax were randomly assigned treatment with radiotherapy to the primary lesion and mediastinum (group C), and radiotherapy plus either four (group B) or eight (group A) courses of high‐dose intermittent cyclophosphamide. Cyclophosphamide therapy delayed the progression of metastatic lesions outside the irradiated field (median interval to progression 192 days for groups A and B vs. 114 days for group C), and prolonged survival (median 306 days for groups A and B vs. 216 days for group C). Assuming a tumor‐doubling time of 18 days, the improved survival of the cyclophosphamide‐treated patients could be explained by the inhibition of 90/18 = 5 tumor doublings or a tumor cell kill of 101,5. This result indicates that cyclophosphamide is only minimally effective in the treatment of lung cancer, but it is an active drug and it should be considered for inclusion in future trials of drug combinations.
115 citations
TL;DR: Phage IKe is sex-factor specific and was isolated using as host a strain of Salmonella typhimurium bearing a transmissible drug-resistance factor (R factor) of the type that does not inhibit F-promoted fertility (fi − ).
99 citations
TL;DR: In this article, an experimental study on the heat transfer performance of a two-phase closed thermosyphon together with a simple theoretical analysis for its maximum heat transfer capacity has been made.
97 citations
TL;DR: In this article, the authors measured the infrared reflectivity as a function of hole concentration at 82 \ifmmode^\circ\else\textdegree\fi{}K for lead-rich alloy samples.
Abstract: The infrared reflectivity was measured as a function of hole concentration at 82 \ifmmode^\circ\else\textdegree\fi{}K for ${\mathrm{Pb}}_{1\ensuremath{-}x}{\mathrm{Sn}}_{x}\mathrm{Te}$ alloy samples with $x=006 \mathrm{and} 021$ and as a function of temperature for one sample with $x=021$ and hole concentration 87\ifmmode\times\else\texttimes\fi{}${10}^{18}$ ${\mathrm{cm}}^{\ensuremath{-}3}$ The measured reflectivity spectra were remarkably well fitted by the classical free-carrier dispersion relations The optical dielectric constant ${\ensuremath{\epsilon}}_{\ensuremath{\infty}}$, the susceptibility effective mass ${m}_{s}$, and the optical mobility ${\ensuremath{\mu}}_{\mathrm{opt}}$ were determined from a curve-fitting technique and a minimum-reflectivity technique generalized to include the effect of nondegeneracy Using the former technique, a second valence-band maximum situated at about 023 eV below the main valence-band maximum was detected in the alloy with $x=021$ The energy gap and ${\ensuremath{\epsilon}}_{\ensuremath{\infty}}$ were found to be related by $\mathrm{ln}{E}_{G}=0086{\ensuremath{\epsilon}}_{\ensuremath{\infty}}+165$ in lead-rich ${\mathrm{Pb}}_{1\ensuremath{-}x}{\mathrm{Sn}}_{x}\mathrm{Te}$ alloys The optical mobility was found to be about a factor of 2 lower than the conductivity mobility in all samples measured The experimental values of ${m}_{s}$ were compared with those expected from the Kane, Cohen, and Dimmock models The results of these comparisons indicate that the two-band models of Kane and Cohen, especially the former, are more suitable than the six-band model of Dimmock to explain the carrier-concentration dependence of ${m}_{s}$, and that none of the models account for the large increase of ${m}_{s}$ with temperature
95 citations
01 Jan 1972
TL;DR: The amygdala must be considered an exception, as investigators have relied almost solely on the Nissl method in determining its nuclear subdivisions.
Abstract: Historically it has been the cytoarchitectural studies of the central nervous system which have provided the foundation upon which concepts concerning the structural organization of specific nuclear regions have been built. In most areas such investigations have included the study not only of Nissl but also of Golgi preparations. In this regard the amygdala must be considered an exception, as investigators have relied almost solely on the Nissl method in determining its nuclear subdivisions.
94 citations
TL;DR: It is concluded that hyperplasia of cardiac muscle and nonmuscle cells is responsible for the increased cardiac mass if cardiomegaly is induced during early postweaning life, while cardiomesgaly induced in adult life gives rise to hypertrophy of cardiac Muscle cells and nonMuscle cells.
Abstract: In our previous studies a twofold cardiomegaly associated with a proportional increase in cardiac DNA was found in rats subjected to a low-iron diet after weaning. To localize the newly synthesized DNA, control and anemic rats 24-34 days of age were given three intraperitoneal injections of 3 H-thymidine (1 µc/g body weight; 22c/mM) at 2-hour intervals. The radioautographs were prepared from sections of the left ventricle stained with PAS-hematoxylin. Between 26 and 34 days of age, significantly larger numbers of labeled nuclei were found in both muscle (31-160/1000) and nonmuscle cells, (29-139/1000) in the hearts of anemic rats as compared to controls (11-49/1000 and 6-35/1000, respectively). When 80-day-old rats were given a low-iron diet, a cardiomegaly of approximately 50% developed. A nonsignificant increase in total cardiac DNA and a small significant increase in labeled cardiac nonmuscle nuclei (16-35/1000) was observed in the anemic groups. We conclude that hyperplasia of cardiac muscle and nonmuscle cells is responsible for the increased cardiac mass if cardiomegaly is induced during early postweaning life, while cardiomegaly induced in adult life gives rise to hypertrophy of cardiac muscle cells and hyperplasia of cardiac nonmuscle cells.
89 citations
TL;DR: In this paper, the impedance characteristics of the silver/aqueous-KOH-solution interface have been studied by the potentiodynamic method using a coupled impedance follower, and the role of dissolution processes in the initial stages of surface oxide formation has been investigated further by means of rotating disk electrode.
88 citations
TL;DR: In this article, it was shown that CH 3 CN occupied 3 Pt sites per molecule at adsorption saturation leaving 33% of the surface available for co-adsorption of H 2 SO 4.
TL;DR: Using tetracycline labelling in vivo and histological analysis of undecalcified longitudinal sections of cortical bone, the average speed was measured with which osteoclastic fronts of the evolving Haversian systems erode bone.
Abstract: Using tetracycline labellingin vivo and histological analysis of undecalcified longitudinal sections of cortical bone, the average speed was measured with which osteoclastic fronts (cutting cones) of the evolving Haversian systems erode bone. This speed reflects the function of the individual osteoclasts within the cutting cone and is opposite to the appositional rate (the thickness of bone deposited by a monolayer of osteoblasts in unit time). In fifty-three Haversian remodeling sites in several sections from four different ribs of three adult dogs, the longitudinal erosion rate (in the direction of long axis of the osteon) averaged 39±14 μ/day, whereas the radial erosion rate, that is the centrifugal enlargement from the tip of the cutting cone to its largest diameter, averaged 7.1±3 μ/day.
TL;DR: Experiments using 14 C and 32 P doubly labelled glycerophosphate provided evidence that phosphatidylglycerol in leaves is biosynthesized via the intermediate formation of phosph atidyl glycerphosphate by the same pathway as in animal tissues and bacteria.
TL;DR: This first demonstration of a biochemical difference between skeletal muscle of cold-acclimated rats and skeletal Muscle of warm-acClimated rats opens up a new approach to the study of the nature of both the adaptation for nonshivering thermogenesis and of the role of the brown adipose tissue in the development and maintenance of this adaptation.
Abstract: The lipid-containing tissues are important in cold-exposure (exposure to cold of animals not previously living in the cold) and in cold-acclimation (the adaptive state achieved when animals have lived in the cold for several weeks); these are the white adipose tissue and the brown adipose tissue. The white adipose tissue serves as a store of readily mobilized substrate (free fatty acids [FFA]) for calorigenesis in other tissues during cold-exposure, principally for shivering thermogenesis in muscle. The mobilization of the sterol lipid is brought about through activation of the sympathetic nervous system by the cold stress. The brown adipose tissue has two functions in cold-exposure and in cold-adaptation, both quite distinct from the function of the white adipose tissue. These functions are heat production and the maintenance of the adaptationto cold. The triglycerides stored in the brown adipose tissue are mobilized as FFA, also via activation of the sympathetic nervous system, but the FFA are used primarily within the brown adipose tissue itself. The FFA are the agents which switch on the calorigenesis in the brown adipose tissue (via a poorly understood form of “loosening” of the coupling of oxidative phosphorylation); they also serve as the substrate for the calorigenesis. The heat-producing function of the brown adipose tissue occurs in both cold-exposed and in cold-acclimated animals; it is of greater importance in the latter because this tissue normally grows in response to cold. Much of the heat production in cold-acclimated animals (nonshivering thermogenesis) occurs outside the brown adipose tissue itself, most probably in the muscles, and the cold-acclimated animal differs from the cold-exposed animal in being able to switch on nonshivering thermogenesis via activation of the sympathetic nervous system. The maintenance of this adaptation for nonshivering thermogenesis in tissue other than the brown adipose tissue itself depends upon the brown adipose tissue. The adaptation disappears if the brown adipose tissue is removed; the adaptation does not develop if the normal proliferation of mitochondria in the growing brown adipose tissue is inhibited (with oxytetracycline) during acclimation of rats to cold. The mechanism by which the brown adipose tissue exerts this second function is at present unknown. An increased turnover of certain mitochondrial proteins occurs in those tissues (skeletal muscle and brown adipose tissue) in which nonshivering thermogenesis occurs in cold-acclimated rats; no change in turnover of mitochondrial proteins occurs in other tissues (liver and kidney). The relation of this alteration in mitochondrial proteins to the adaptation for nonshivering thermogenesis is at present unknown. However this first demonstration of a biochemical difference between skeletal muscle of cold-acclimated rats and skeletal muscle of warm-acclimated rats opens up a new approach to the study of the nature of both the adaptation for nonshivering thermogenesis and of the role of the brown adipose tissue in the development and maintenance of this adaptation.
TL;DR: In this article, a number of properties of the bound eigenstates of an electron in an exponential cosine screened Coulomb potential, including the number of different energy levels, were studied.
Abstract: A number of properties of the bound eigenstates of an electron in an exponential cosine screened Coulomb potential, $V(\mathcal{r})=\ensuremath{-}(\frac{{e}^{2}}{\ensuremath{\kappa}\mathcal{r}}){e}^{\ensuremath{-}qr}cos(q\mathcal{r})$, are studied. Perturbation and variation methods are used to calculate the eigenvalues. Detailed results are presented for the first four $s$ states. For each state there is a critical value of the screening parameter ${\ensuremath{\delta}}_{c}$ above which no bound states with negative energy exist. The value of ${\ensuremath{\delta}}_{c}$ for the ground state is obtained from a two-parameter variational calculation. The total number of different energy levels is finite for any value of the screening parameter $\ensuremath{\delta}$ greater than zero, and is found to be approximately linearly dependent on $\frac{1}{{\ensuremath{\delta}}_{c}}$, The square of the number of bound $s$ states is also shown to be linear with $\frac{1}{{\ensuremath{\delta}}_{c}}$, Positive-energy states are also discussed.
TL;DR: The non-polar fraction studied here contained, in addition to the previously reported squalenes and vitamin MK-8, the following C 40 -carotenoids: phytoene, cis - and trans -phytofluenes, neo -α- carotene, β-carotene and neo -β-carotsene.
TL;DR: In this paper, a review of diffusivities in carbon tetrachloride and hexane at 25°C indicated that the diffusivity of essentially linear molecules were, in general, about 30 per cent higher than for substances composed of essentially spherical molecules having the same molar volume at the normal boiling point.
TL;DR: Findings are consistent with a tendency for harder water to reduce the risk of death in general, rather than from cardiovascular causes in particular, by a margin of up to 15%, or as much as 30%, depending on the geographical units of study employed in the analysis.
TL;DR: A large deposit of ferromanganese oxide coated sands and scattered manganese nodules occurs in the northern portion of Lake Ontario as discussed by the authors, and the composition and compositional variations in the deposit possibly can be explained in terms of the fractionation and precipitation of Fe and Mn as a result of redox variations in lake sediments.
Abstract: A large deposit of ferromanganese oxide coated sands and scattered manganese nodules occurs in the northern portion of Lake Ontario. The Mn and Fe contents of the concretions are similar to those in concretions from other environments, while their Ni, Cu, and Co contents are lower than in deep-sea nodules, but higher than in most previously described lacustrine concretions. Pb and Zn are high in the coatings and exceed the concentrations found in many previously analyzed Mn deposits. Within the deposit, Mn, Ni, Co, and Zn contents are correlated, and they vary inversely with Fe. Mn, Fe, Ni, Cu, and Pb are present in the interstitial waters of the sediments underlying the deposit in higher concentrations than in the overlying lake waters, thus providing a potential source of metals for concretion formation. The origin and compositional variations in the deposit possibly can be explained in terms of the fractionation and precipitation of Fe and Mn as a result of redox variations in the lake sediments. Eh increases from south to north across the deposit in such a way that iron may be selectively oxidized and precipitated in the south and manganese, in the north. The upward diffusion of Mn, Fe, and associated elements from the underlying sediments probably provides the principal source of the metals in the south of the deposit, while metal-enriched bottom waters are probably the principal source in the north.
TL;DR: A preliminary hypothesis to account for the effects of nutrients on pigmentation is presented, and addition of glycerol or glucose to BSMK increased the formation (relative to squalene) of dihydrosqualene, tetrahydrosqualenes, and vitamin MK8.
Abstract: 1.
Cells of the extremely halophilic bacteria, Halobacterium cuti-rubrum and H. halobium grown in a chemically defined medium (BSMK) were red due to the presence of bacterioruberins (maxima, 370, 388, 494 and 527 nm). Adding 0.1% glycerol to BSMK stimulated growth, but cells rapidly lost bacterioruberins becoming greyish purple in the stationary phase. Acetone extracts of these cells were yellow with a broad absorption band at 360–390 nm, partly attributable to retinal. In BSMK medium with or without glucose, the bacterioruberin concentration increased until maximal growth was reached, then fell rapidly.
2.
In complex medium (CM) cells formed less bacterioruberins than in BSMK. Adding 0.1% glycerol to CM stimulated growth but did not change pigmentation; adding glucose only slightly stimulated growth but greatly increased bacterioruberin formation. Exposure to visible light did not affect growth or pigmentation.
3.
Addition of glycerol or glucose to BSMK increased the formation (relative to squalene) of dihydrosqualene, tetrahydrosqualene, and vitamin MK8. Higher levels of these compounds were found in cells grown in CM than in BSMK. Though glycerol decreased the formation of bacterioruberins it increased the formation of β-carotenes. Glucose increased the formation both of bacterioruberins and β-carotene. A preliminary hypothesis to account for the effects of nutrients on pigmentation is presented.
TL;DR: Iron-rich sediments chemically similar to those forming on the crest of the East Pacific Rise have been found just above basement at widely separated drill sites in the eastern equatorial Pacific, including three sites of Leg 16 of the Deep Sea Drilling Project.
Abstract: Iron-rich sediments chemically similar to those forming at present on the crest of the East Pacific Rise have been found just above basement at widely separated drill sites in the eastern equatorial Pacific, including three sites of Leg 16 of the Deep Sea Drilling Project. These sediments were probably formed when the basement was at the crest of this rise and have moved to their present location as a result of sea-floor spreading.
TL;DR: The results indicate that thyroid hormone exerts an important regulatory influence on the activities of hexokinase, phosphofructokinase and pyruvate kinase in the developing cerebral cortex and cerebellum of the rat.
Abstract: — The regulation by thyroid hormone of the activities of hexokinase (ATP: D-hexose 6-phosphotransferase; EC 2.7.1.1), phosphofructokinase (ATP: D-fructose-6- phosphate 1-phosphotransferase; EC 2.7.1.11) and pyruvate kinase (ATP: pyruvate phosphotransferase; EC 2.7.1.40) has been investigated in the soluble fractions of the cerebral cortex and cerebellum of the rat. Ontogenetic studies on these key glycolytic enzymes demonstrated marked increases in the normal cerebral cortex between 1 day and 1 yr of age; less pronounced increases in enzyme activities were noted in the normal cerebellum. Neonatal thyroidectomy, induced by treatment of 1-day-old rats with 100 μCi of 131I, ied to an impairment of body and brain growth and inhibited the developmental increases in hexokinase, phosphofructokinase and pyruvate kinase in both the cerebral cortex and cerebellum. Whereas 50 μCi of 131I had little or no effect on these brain enzymes, 200 μCi of the radioisotope markedly inhibited (35–65 per cent) the developmental increases of the various enzyme activities investigated. When administration of the radioisotope was delayed for 20 days after birth, little or no inhibition of the development of brain glycolytic enzymes was observed. Whereas treatment of normal neonatal animals with L-tri-iodothyronine had no significant effect on the activities of cerebro-cortical and cerebellar glycolytic enzymes, the hormone increased their activities in young cretinous rats. However, when the initiation of tri-iodothyronine treatment was delayed until neonatally thyroidectomized rats had reached adulthood, this hormone failed to produce any appreciable change in enzyme activity. Our results indicate that thyroid hormone exerts an important regulatory influence on the activities of hexokinase, phosphofructokinase and pyruvate kinase in the developing cerebral cortex and cerebellum.
TL;DR: In this article, the photo-effect in anodic anodic oxidation of silver electrodes has been examined by means of potentiodynamic and ac impedance-following techniques and the rise times of the photo effect have been determined.
TL;DR: A red-pigmented organism, formerly known as marine psychrophile NRC 1004, has been classified as Vibrio psychroerythrus sp.
Abstract: A red-pigmented organism, formerly known as marine psychrophile NRC 1004, has been classified as Vibrio psychroerythrus sp. n. Classification was mainly based on morphology, the ability of the organism to oxidize and ferment glucose, its sensitivity to vibriostat 0/129, and its deoxyribonucleic acid base composition of 40.0 moles% guanine plus cytosine, determined by thermal denaturation. The organism gave positive reactions for catalase, oxidase, and starch hydrolysis and produced acid from maltose and dextrin but not from arabinose. It was indole- and citrate-negative and reduced nitrate to nitrite without producing gas.
TL;DR: Lesions placed lateral to the tail of the caudate nucleus did not cause degeneration in the globus pallidus or in the substantia nigra, and Fibers from all parts studied follow a similar dorsomedial course along the ventral border of the lentiform nucleus.
TL;DR: Turnover and synthesis of phosphatide species were examined simultaneously at either 37 or 10 °C and the increase in unsaturation accompanying cold exposure is discussed in terms of possible factors influencing cyclopropane fatty acid synthesis as well as other phenomena.
TL;DR: The structure of the squalene in Halobacterium cutirubrum was shown to be identical with that of authentic all trans-squalene from shark liver and that of tetrahydrosqualene has been established.
TL;DR: It was concluded that separate transferases were responsible for the formation of the two types of glycosides, including monoglucuronides and glucosides, which were formed in much lesser yield than the glucuronides.
Abstract: 1. Rabbit liver microsomal fractions in vitro effected the transfer of glucuronic acid from UDP-glucuronic acid to biochanin A, formononetin, daidzein, genistein and equol. Only monoglucuronides were formed. 2. The same isoflavones were converted into monoglucosides when UDP-[6-(3)H]glucose was substituted for UDP-glucuronic acid in the incubation medium in vitro. The glucosides were formed in much lesser yield than were the glucuronides. 3. The glucoside of genistein was identified as genistin (genistein 7-glucoside) by Sephadex chromatography and reverse isotope dilution. 4. The specificity of the glucuronyl- and glucosyl-transfer mechanisms was compared for a series of steroids and other phenols in addition to the isoflavones. It was concluded that separate transferases were responsible for the formation of the two types of glycosides.