Studies on Analytical Methods for Trace Elements in Metals by Using Radioactive Isotope. IV : Determination of Aluminium with Calcium-45 Type Cation Exchanger

Aluminium was determined radiometrically by using calcium-45 isotope and cation exchange resin. The sample solution containing Al^3+ was adjusted to pH 3.0～4.0 and was treated with the cation exchanger of Ca-R type labeled with calcium-45. The radioactivity of eluted calcium was exactly equivalent to the amount of aluminium ion present. Interferences of ferrous iron, magnesium ion and ammonium ion were examined, and no serious effect was observed. This method was applied to the determination of aluminium in carbon steel, and the results obtained agreed with those by photometric method

Studies on Analytical Methods for Trace Elements in Metals by Using Radioactive Isotope. III : Determination of Tantalum by Means of Isotope Dilution Method

The determination of tantalum by isotope dilution method in the presence of niobium was investigated by the use of radioactive isotope tantalum-185. Tantalum was separated from niobium as tantalum-tannin precipitate under the optimum condition of pH 1.9～2.5 and tantalum/niobium ratio up to 1/50. If niobium had been present 100 times or more of tantalum, reprecipitation would have been needed. The reciprocal of the specific activity of tantalum pentoxide preciptiate was in a linear relation to the change in the amount of tantalum added. The recommended method gave an accurate result in the determination of tantalum in steel

Studies on Analytical Methods for Trace Elements in Metals by Using Radioactive Isotope. V : Determination of Hafnium in Zirconium by Means of Isotope Dilution Method

A method for the determination of hafnium in zirconium metal was studied. Hafnium was enriched from hydrochloric acid solution of zirconium sample with four steps of thiocyanate-hexone extraction-stripping method. After the several steps of extraction, pure hafnium fraction was obtained by passing the solution through the cation exchanger resin column, and eluting with the mixture of 0.45 M nitric acid and 0.095 M citric acid as an eluent. Combining the isotope dilution method and the above mentioned method, hafnium which existed from 0.025 to 0.1 per cent in zirconium was determined

Allergic inflammation, its development mechanism and per­meability of cell membrane

The ascitic monocytes and subcutaneous cells and tissues of sensitized animals have been observed after exposing to antigen for the purpose of revealing the disintegration processes of the cells related with inflammation and it has been proved that the permeability of the cell membrane increases markedly resulting in the swelling of the cells at the moment when the cells come in contact with antigen. The localization of the antigen in the Arthus' phenomenon will be the results of the gelatination of the inter-cellular tissues and the swelling of cells. And it is indicated that the cell death accompanied by an allergic inflammation is caused by the increased permeability of the cell membrane which will result in the activation of the intra-cellular enzymes followed by the acute disintegration of the molecular structure of the cell and release of the so-called inflammatory substances.</p

Immunohistochemical Examination on the Distribution of Cells Expressed Lymphatic Endothelial Marker Podoplanin and LYVE-1 in the Mouse Tongue Tissue

The clinical study for lingual disease requires the detailed investigation of the lingual lymphatic network and lymphatic marker-positive cells. Recently, it has been reported that several tissue cells and leukocytes express lymphatic markers, LYVE-1 and podoplanin. This study was aimed to clarify the lingual distribution of cells expressing LYVE-1 and podoplanin. In the mouse tongue, podoplanin is expressed in nerve sheaths, lingual gland myoepithelial cells, and lymphatic vessels. LYVE-1 is expressed in the macrophage marker Mac-1-positive cells as well as lymphatic vessels, while factor-VIII was detected in only blood endothelial cells. α-SMA was detected in vascular smooth muscle and myoepithelial cells. Therefore, identification of lymphatic vessels in lingual glands, the combination of LYVE-1 and factor-VIII, or LYVE-1 and Mac-1 is useful because myoepithelial cells express podoplanin and α-SMA. The immunostaining of factor-VIII on lymphatic vessels was masked by the immunostaining to LYVE-1 or podoplanin because lymphatic vessels express factor-VIII to a far lesser extent than blood vessels. Therefore, except for the salivary glands, the combination of podoplanin and α-SMA, or factor-VIII is useful to identify lymphatic vessels and blood vessels with smooth muscle, or blood capillaries

Optimal portfolios with end-of-period target

We study the estimation of optimal portfolios for a Reserve Fund with an end-of-period target and when the returns of the assets that constitute the Reserve Fund portfolio follow two specifications. In the first one, assets are split into short memory (bonds) and long memory (equity), and the optimality of the portfolio is based on maximizing the Sharpe ratio. In the second, returns follow a conditional heteroskedasticity autoregressive nonlinear model, and we study when the distribution of the innovation vector is heavy-tailed stable. For this specification, we consider appropriate estimation methods, which include bootstrap and empirical likelihood