Showing papers by "The Chinese University of Hong Kong published in 1975"
TL;DR: In this paper, Hartree-Fock calculations have been performed on the ground and on the first excited states of NaO, KO and RbO, and it is found that the former and the latter two molecules, though valence-isoelectronic, have their first two low-lying electronic states in reversed order.
38 citations
TL;DR: The evolution of epidermal glands in gekkonid lizards is reviewed; the cellular dynamics of β‐glands are compared with those of unspecialized epidermis; the possibility that gekKonine epidersmal glands respond to quantitative variation in circulating testosterone titers is discussed.
Abstract: The gross and microscopic anatomy of epidermal glands has been studied in laboratory maintained tokays (Gekko gecko), and house geckos (Hemidactylus bowringii) captured from the wild throughout the year. Annual testicular activity in the house gecko has also been studied. While no significant differences in glandular development at various times have been observed in G. gecko, there are clear-cut annual cycle in H. bowringii. The evolution of epidermal glands in gekkonid lizards is reviewed; the cellular dynamics of β-glands are compared with those of unspecialized epidermis; the possibility that gekkonine epidermal glands respond to quantitative variation in circulating testosterone titers is discussed.
37 citations
TL;DR: In this article, the authors measured the heat capacities of poly(vinyl fluoride, polyvinylidene fluoride, and polytrifluoroethylene, and concluded that the force constant for one-dimensional intrachain interaction is approximately constant for all polymers with carbon backbones.
Abstract: The heat capacities of poly(vinyl fluoride), poly(vinylidene fluoride), and polytrifluoroethylene have been measured between 80 and 340°K. The results can be expressed as the sum of two terms: the optical contribution calculated from the vibrational band assignments in the literature and the acoustical contribution calculated according to the Tarasov continuum model. Combining our data with those for polyethylene and polytetrafluoroethylene, it is concluded that the force constant for one-dimensional intrachain interaction is approximately constant for all polymers with carbon backbones. The force constant for three-dimensional interchain interaction is one order of magnitude smaller than the one-dimensional force constant, and decreases when the hydrogen atoms in polyethylene are replaced by fluorine atoms. The thermodynamic functions for the three polymers have been evaluated. Glass transitions at 228°K and 305°K have been found in poly(vinylidene fluoride) and polytrifluoroethylene, respectively.
30 citations
TL;DR: In vivo and in vitro experiments on the endocrine relationships of epidermal glands in the tokay Gekko gecko, and the common house gecko Hemidactylus bowringii are reported, showing that certain aspects of land differentiation involve a synergistic action between androgens and those hormones responsible for controlling the normal shedding cycle.
Abstract: In vivo and in vitro experiments on the endocrine relationships of epidermal glands in the tokay Gekko gecko, and the common house gecko Hemidactylus bowringii are reported. The results show that certain aspects of beta-gland differentiation involve a synergistic action between androgens and those hormones responsible for controlling the normal shedding cycle, while other aspects are solely under androgenic control. Pre-anal organ activity appears to be solely under androgenic control.
20 citations
TL;DR: The main thrust of this paper is to present a new algorithm for the analysis of structure in multivariate data point clusters from the standpoint of intrinsic (topological) dimensionality.
Abstract: The main thrust of this paper is to present a new algorithm for the analysis of structure in multivariate data point clusters from the standpoint of intrinsic (topological) dimensionality.
17 citations
TL;DR: Ab initio molecular orbital calculations predict an planar geometry for the ground state of AlCl3 as discussed by the authors, which is the state of the art in the field of molecular orbital geometry and physics.
16 citations
TL;DR: Significant increases in the oxygen consumption rate were observed when these squamates were maintained at or above 30°C, and there was a discrepancy between the 2 sub-orders of the squamate reptiles.
Abstract: 1. 1. The effects of temperature and/or the thyroid hormone on the oxygen consumption of lizard ( Hemidactylus ) and snake ( Ptyas ) liver tissue were examined. 2. 2. Significant increases in the oxygen consumption rate were observed when these squamates were maintained at or above 30°C. 3. 3. At 30°C, experimentally induced hypothyroid condition (thyroidectomy) and hyperthyroid condition (thyroxine injection) resulted in an increase or decrease respectively in the oxygen consumption in the lizard. Such treatment however produced no apparent effect in the snake. 4. 4. The reason for this discrepancy between the 2 sub-orders of the squamate reptiles remains to be sought.
15 citations
TL;DR: In this article, the ultrasonic velocities and attenuations of poly(vinylidene fluoride), poly trifluoroethylene and polychlorotrifluorethylene at 10 MHz from 170 to 300 K were measured by the pulse echo-overlap and the pulse-height comparison methods, respectively.
15 citations
TL;DR: Spectrophotometric titration of cardiotoxin showed that only one of the three tyrosine residues was titrated freely with a normal apparent pKa of 9.4 whereas the other two ionized at pH above 10.5 after an irreversible conformational change had occurred.
15 citations
TL;DR: In this paper, a modified Frohlich equation for oriented dipoles was applied to poly(ethylene terephthalate) films of different draw ratios and the dielectric relaxation strength was determined from the Cole-Cole plot.
Abstract: Dielectric experiments were performed in the β temperature region on poly(ethylene terephthalate) films of different draw ratios. The proportion of various conformations, crystallinity, and orientation were estimated from infrared, density, and birefringence measurements. The dielectric relaxation strength was determined from the Cole–Cole plot of the dielectric constants over a wide frequency range. An attempt was made to modify the Frohlich equation, originally for isotropic systems, for application to systems of oriented dipoles. When the experimental data are analyzed through this modified equation, it is evident that the changes in the dielectric constants of PET with stretching could not be accounted for by improvement in the alignment of chain molecules alone. The relative abundance of the trans conformation, both crystalline and amorphous, and gauche conformation appears to be a factor which cannot be ignored. The calculation indicates that the dipole moment seems to be greater in the trans conformation than in the gauche conformation.
13 citations
TL;DR: It is shown that both hormones are stimulatory in the snake, but not in the turtle, and the biosynthesis of these iodinated compounds by the thyroid tissue varied among species.
TL;DR: In this paper, the effect of heating rate on the activation energy derived from the dynamic kinetic method of bromophenol blue has been investigated and it was found that activation energy increases as the heating rate decreases.
Abstract: Alkaline fading of bromophenol blue was chosen for the investigation of the effect of heating rate on the activation energies derived from the dynamic kinetic method. Freeman and Carroll's treatment was adopted to compute the activation energies from experimental data taken with three heating rates: namely 1°, 0.5° and 0.25°/min. It was found that the activation energy increases as the heating rate decreases. This is attributed to the non-equilibrium conditions. By extrapolating to zero heating rate, the activation energy obtained is comparable to that obtained via classical isothermal kinetics.
TL;DR: In this paper, the molecular motions in polytrifluoroethylene are studied by dynamic mechanical and dielectric measurements and two absorption peaks (αa, β) have been observed in the frequency range from 3 Hz to 300 kHz and in the temperature range from −150° to 130°C. The molecular mechanisms for these absorptions are discussed, and results are compared with ultrasonic, heat capacity and n.m.c.r.
01 Jan 1975
TL;DR: Cardiotoxin produced a biphasic effect on hormonal-responses in isolated cell systems and inhibited ACTH-stimulated lipolysis in isolated fat cells and steroidogenesis in isolated adrenal cells, and it was postulated that cardiotoxin might act at the plasma membrane level, either binding irreversibly on the membrane or perturbing the plasma membranes conformation leading to an irreversible change in the activity of the membrane-bound adenyl cyclase.
TL;DR: In this paper, the molar heat capacity of a 45:55% copolymer of ethylene and tetrafluoroethylene was measured using an adiabatic calorimeter, to an accuracy of 0.3%.
TL;DR: In this paper, the resolving power is shown to vary from extremely good to worse than that based on the Rayleigh criterion, depending upon the location of the illuminated area on the hologram during reconstruction.
TL;DR: In this article, a relativistic differential cross section is proposed for the scattering of a coherent radiation by a free electron. The angular behaviour of this formula is shown quite similar to that of Klein-Nishina for incoherent radiation.
TL;DR: The rate of MIT deiodination in the liver and kidney of gecko was similar (4 −6 × 10 −4 μg/min/mg tissue), and was 4-fold greater than the liver of turtle.
Abstract: 1. 1. Deiodinating activity of mono-iodotyrosine of liver and kidney in Geoclemys reevesii, Gekko gecko and Elaphe taeniura was examined. 2. 2. Deiodination was assessed by measuring 125 I during a 20-min incubation of liver or kidney homogenate in a buffered medium containing 125 I-MIT. 3. 3. No deiodinating activity was shown in liver and kidney of snake, and the kidney of turtle. 4. 4. The rate of MIT deiodination in the liver and kidney of gecko was similar (4 −6 × 10 −4 μg/min/mg tissue), and was 4-fold greater than the liver of turtle.
TL;DR: In this article, a sealed-tube type 14 MeV neutron generator with maximum neutron output of 10 11 n/sec, incorporating a pneumatic sample transfer system of single tube type and with a single rotation of the sample during neutron irradiation, is used to develop a method for determining oxygen content in steel in the ppm range with the best precision, and at the same time, to make the process suitable for routine work in industrial applications.
TL;DR: In this paper, the spectrum of the Hg arc was reconstructed using a holographic method and the doublet 5770A, 5790A was resolved but Rayleigh's criterion predicts the contrary.
TL;DR: Two types of bipolar cells are identified in the chick embryonic retina and they can be distinguished by their cytoplasmic organelles.
Abstract: Two types of bipolar cells are identified in the chick embryonic retina. They can be distinguished by their cytoplasmic organelles.
TL;DR: In this paper, the authors examined the relation of the anisotropic permittivity of an axially symmetric dielectric to the experimentally measurable anisotropy, u, in the permittivities ϵ.
TL;DR: In this article, it was shown that any measure with support containing that of θ is nilpotent, and the set of measures with support is convex and dense in P(S).
Abstract: Let S be a compact semigroup and P(S) the set of probability measures on S. Suppose P(S) has zero θ and define a measure μ ε P(S) nilpotent if μn → θ. It is shown that any measure with support containing that of θ is nilpotent, and the set of nilpotent measures is convex and dense in P(S). A measure μ is called mean-nilpotent if (μ + μ2 + … + μn)/n → θ, and can be characterized in terms of its support.