Studies on syntheses and permeabilities of special polymer membranes. 22. Ultrafiltration characteristics and membrane structure of cellulose nitrate membranes

The formation mechanism of anisotropic polymer membranes formed by a system of cellulose nitrate (CN)/n-propyl alcohol (n-PrOH)/N,N-dimethyl formamide (DMF) was investigated. The ultrafiltration characteristics and the membrane structure were influenced significantly by the casting solvents (ratio of n-PrOH to DMF) and the evaporation period during the membrane formation process. The finger-like structure in the sponge layer was observed in all systems except that of n-PrOH/DMF = 2/1 and increased with the evaporation period, after 2 min in the system of pure DMF and after 5 min in the system of n-PrOH/DMF = 1/3. The formation mechanism of the anisotropic CN membranes and the ultrafiltration characteristics were discussed in detail.     

Complement system in human colostrum: presence of nine complement components and factors of alternative pathway in human colostrum

Evidence has been obtained for the presence in human colostrum of all nine components of complement (C), C1 through C9, and factors of the alternative pathway. Samples of colostrums collected from five women at 1-4 days after normal parturition were assayed for the haemolytic activities of individual components. As compared with normal human sera, the activities of each component ranged from 0.03 to 7% of those in sera. The activities of C4, C7 and C9 were relatively high, while that of C1 was extremely low. In most of the cases, the activities of individual components gradually increased following delivery, when expressed as the activity per unit weight (g) of protein in the colostrum. When the colostrums were treated with cobra venom factor, most of the colostrums showed 10-20% reduction in the C3 activity. This finding indicates the presence of factors such as B and D which are involved in the activation of C through the alternative pathway. The role as a defense factor of the C system in human colostrum and milk is discussed in connection with the ability of secretory IgA to react with C.     

Polymerization of 1-butyne and isopropylacetylene by transition metal catalysts and geometric structure of polymers

Polymerization of 1-butyne and isopropylacetylene was studied using MoCl₅, WCl₆, and two Ziegler catalysts [Fe(acac)₃-Et₃Al, Ti(On-Bu)₄-Et₃Al]. 1-Butyne was polymerized in high yields with WCl₆ and Fe(acac)₃-Et₃Al to give a yellow, air-sensitive polymer. The cis content of poly(1-butyne), evaluated by ¹³C n.m.r., was about 80% irrespective of polymerization conditions. Isopropylacetylene was polymerized well by any of MoCl₅, WCl₆, and Fe(acac)₃-Et₃Al; the polymer formed was a light yellow air-sensitive powder. The cis content of poly(isopropylacetylene) varied from 65% to 90% according to polymerization conditions. Substituent effects on polymerization and polymer structure are discussed.     

The anodic polarization characteristics of the graphite in alkaline solution

The anodic behaviour of a graphite electrode in alkaline solution was studied by means of the linear potential sweep method, the controlled potential electrolysis and the colourimetry. Linear sweep polarization curves indicated that the surface of graphite electrode is oxidized in the anodic region from ?0.3V.The numbers of electron participating in the oxidation of a carbon atom was calculated to be 1, 2, and 2 at 0.2, 0.3, and 0.4V, respectively, based on the quantity of electricity which was measured by the controlled potential electrolysis and the numbers of carbon atom on the surface of the graphite electrode, which was calculated with the double layer capacity.The structure of oxide layer formed on the graphite electrode was examined by the colourimetry with HgBr₂ and NaOEt. It was found that the oxide layer on the electrode contained carbonyl groups.     

Thermodynamics of oxygen and nitrogen in liquid iron equilibrated with CaO- SiO2-Al2O3 slags

Nitrogen distribution ratios, L_N ( = (mass pct N)/[mass pct N]), between CaO-SiO₂-Al₂O₃ slags and liquid iron were measured at 1823 and 1873 K as a function of Si (or Al) content in metal, using lime and alumina crucibles. Based on these results and the reported values for activities of SiO₂ (or Al₂O₃), nitride capacities, C_(N), defined by (mass pct N) · PO₂/3/4/PN₂/1/2 were evaluated. Activities of SiO₂ (or Al₂O₃) obtained by using the values for L_N and C_(N) obtained in present and previous gas-slag experiments were compared with previous results. FUMIHIKO TAMURA formerly Graduate Student with the Department of Metallurgical Engineering, Tohoku University.     

Ambulatory oxygen uptake measurement system

An apparatus for monitoring prolonged measurement of oxygen uptake without discomfort has been developed. The system is based on the open flow-through principle. The subject wears a hood through which air is drawn by an exhaust blower. Oxygen concentration is kept constant by a servo-controlled blower, so that flow rate is essentially proportional to oxygen uptake. The flow rate of the main stream is measured by a time-of-flight flowmeter located in the exhaust hose. Oxygen concentration is measured by a limiting-current oxygen sensor. The signals representing flow rate and oxygen concentration are digitized and stored in a memory. All of the equipment is assembled in a small package (wt = 3 kg) which the subject carries on his back. The memory chip is removed from the portable device after each experiment. Data are transferred from the memory to a microcomputer and then an oxygen uptake trend is estimated. Response of the system to a step input is about 30 s. Compared with a commercially available oxygen monitoring system (Magna 88, P. K. Morgan Ltd., Rainham, UK), the maximum difference was 0.15 L/min within an oxygen uptake range of 0.25-2.3 L/min. Thus, the measurements made with our portable device agree with the results obtained using the conventional method.     

3-D reconstruction using mirror images based on a plane symmetryrecovering method

Three-dimensional reconstruction from a perspective 2D image using mirrors is addressed. The mirrors are used to form symmetrical relations between the direct image and mirror images. By finding correspondences between them, the 3D shape can be reconstructed by means of plane symmetry recovering method using the vanishing point. Two constraints are used in determining the correspondence. In the case where only one mirror is used, invisible parts both in the direct image and in the mirror image may still remain. Using multiple mirrors, however, occluded parts will decrease or disappear, and occlusion-free object reconstruction becomes possible