Hydroxyl group formation caused by hydrogen diffusion into optical glass fibre

Transmission loss increase of optical glass fibre caused by hydrogen diffusion is measured as a function of temperature and partial pressure of hydrogen gas. The activation energy of hydroxyl group formation from the diffused molecular hydrogen was found to be 15.9 kcal/mole. Also the hydroxyl absorption loss increase at 200°C was found to be proportional to the square root of the partial pressure of hydrogen gas.     

A special type of small granule-containing cell in the abdominal para aortic region of the frog

Light and electron microscopic studies have been made of a special type of small granule-containing cell (termed Type IV cell) in the frog abdominal para aortic region. These cells contain numerous dense granular vesicles (100--150 nm in diameter) and are considerably smaller (10--20 mu) than neighbouring nerve cells, although they have many features in common with them. They do not resemble chromaffin cells as do Types I, II and III cells. The cell bodies are completely ensheathed by satellite cells and are isolated from neighbouring cells of the same type. Type IV cells have long processes which usually become incorporated in bundles containing 2--20 processes, including some cholinergic nerve fibres, and are loosely enveloped by perineurium. The termination of the processes of Type IV cells do not appear to form efferent synapses on nerve cells at least within the para aortic region or in paravertebral sympathetic ganglia. A close topographical relationship is not found between these processes and blood vessels. It is suggested that the small Type IV granule-containing cells in the frog abdominal para aortic region are not interneurons or neurosecretory cells, but are a special type of sympathetic nerve cell.     

Analyses of differential sensitivities of synchronized HeLa S3 cells to radiations and chemical carcinogens during the cell cycle. Part IV. X-rays

Radiation-induction and rejoining of single-strand breaks (SSBs) in the DNA of synchronized HeLa S3 cells were investigated by alkaline sucrose density gradients. We could not find any significant differences in the extent of SSBs induced in cellular DNA and in the extent of their rejoining throughout the cell cycle, including mitosis. The cyclic variation curve of the content of non-protein sylfhydryls (NPSH) during the cell cycle is similar to that of X-ray survivals except in mitosis, although there was no close correlation between the content of apparent total sulfhydryls (APSH) and X-ray survivals. Radiation-induced mutants resistant to 8-azaguanine (8AG) occurred in higher frequency in the radio-sensitive G1-S boundary phase than in the radio-resistant G1, S and early G2 phases. Further, the pre-irradiation treatment with 50 mM cysteamine prevented reproductive death and induction of 8AG-resistant mutants by X-rays throughout the cell cycle. These findings seem to indicate that there is a close correlation between the extent of lethal radiation damage to the cells and their mutability, and that sulfhydryls may play an important role as a factor governing cellular radio-sensitivity.     

Finite spectrum assignment problem for systems with delay in state variables

This correspondence is concerned with the finite spectrum assignment problem for linear systems with delay in state variables. A systematic procedure for constructing the feedback law is presented on the basis of advanced elementary row operations on matrices with two variablessandz = e^{-sh}.     

Periodic control of continuous stirred tank reactors—III: Case of multistage reactors

The optimal periodic control of a multistage CSTR in which a nonisothermal parallel reaction is taking place is investigated. By applying the infinite-frequency pi criterion it is examined in what condition the optimal periodic control is proper. Then, the optimal steady control and the suboptimal periodic control are determined by numerical calculation. The results indicate that the improvement in the reactor performance for the periodic control relative to that for the steady control is very much increased with increase in the number of stages.     

Spectrum of thermal voltage fluctuations in current-driven,small-capacitance Josephson junctions

We have calculated the spectrum of thermally induced voltage fluctuations in a small-capacitance, current-driven Josephson junction, within the resistively shunted model but with no other approximations. We exploit a novel representation of the solution to the initial value problem for the diffusion of the phase to reduce the fluctuation spectrum to integrals. Numerical results are presented.