Synthesis and properties of hydrophilic copolypeptide membranes containing L-aspartic acid as one component

Three-component random copolypeptide consisting of N-hydroxypropyl-L -glutamine, L -aspartic acid, and L -lysine, related two component random copolypeptides and homopolypeptides, were prepared by carrying out aminolysis reaction with 3-amino-1-propanol, followed by crosslinking reaction with 1,8-octamethylenediamine on starting polymer membranes consisting of γ-methyl-L -glutamate, L -aspartic acid, and L -lysine. The effective crosslink density was shown to be proportional to the content of the crosslinker in the reaction mixture. The tensile properties of these hydrophilic membranes were highly dependent on the degree of swelling in the pseudoextracellular fluid, hydrophobicity of the side chains, and the effective charge density of membranes, and their behavior was typical of an elastomer. A higher rate of water permeability was obtained with charged membranes than noncharged and/or compensated charged membranes with the same order of the degree of swelling in the pseudo-extracellular fluid. Biodegradation of the samples in vitro by papain indicated that the degradation could be regarded as a bulk rather than a surface phenomenon. The rate of degradation was also highly dependent on the degree of swelling of membranes, as well as on the hydrophobicity and the effective charge density of side chains of sample membranes.     

Analysis of direct current potential field around multiple random cracks

A method for evaluating the distribution of electrical potential around multiple through cracks is proposed. The method gives accurate potential values for cracks with different lengths at random positions by combining theoretical potential functions for a single crack in an infinite plate. The validity of the method is numerically confirmed with respect to problems of a single and three cracks existing in a square plate subjected to a current flow, and the method is applied to a problem of random cracks in an infinite plate.     

Image compositing based on virtual cameras

The virtual camera method presented integrates computer graphics and real-time video processing techniques in a new type of virtual studio. At NHK we developed several image compositing systems based on this method. First we look at the virtual camera method, then some of the systems developed with it. Then we discuss future directions and possibilities not only for image compositing but also for the development of sophisticated systems for editing and producing television programs     

Approach by zeta-potential measurement on the surface change of hydrating C3S

The adsorption of Ca²⁺ on C₃S surface and the formation of C-S-H in the induction period of C₃S hydration were investigated by measuring zeta-potential, heat evolution change and by analyzing dissolved ions. Within 20 minutes, the dissolution of Ca²⁺ and silicate ions and the adsorption of Ca²⁺ on the surface of C₃S were alternately repeated. In the induction period (20 50 minutes), Ca²⁺ was adsorbed fairly strongly on C₃S surface giving positive zeta-potentials and the dissolution stopped for a time. In the hydration between 60 and 140 minutes, the C-S-H gel proceeded to crystallize and Ca²⁺ began to dissolve again, giving negative zeta-potentials by Si-O⁻. After 140 minutes, the second evolution was caused by the crystallization of C-S-H and Ca(OH)₂.     

Assembly of bacteriophage phi X174: identification of a virion capsid precursor and proposal of a model for the functions of bacteriophage gene products during morphogenesis

A capsomeric structure sedimenting with an S value of 108 in sucrose gradients was isolated from Escherichia coli infected with bacteriophage phi X174. The 108S material contained viral proteins F, G, H, and D, and the relative amounts of these proteins in the 108S material were similar to those in the infectious 132S particle, which has previously been described as a possible intermediate in the assembly of 114S phage particles. Electron micrographs indicated that the size and shape of the 108S material resemble those of the 132S particle. The 108S material contained no DNA, and its formation occurred independently of DNA synthesis. The 108S material accumulated in infected cells when viral DNA replication was prevented either by mutation in phage genes A or C or by removal of thymidine from a culture infected with wild-type phage or with a lysis gene E mutant. Upon restoration of thymidine to cells infected with the lysis gene E mutant and then starved of thymidine, the accumulated 108S material was converted to 132S particles and to 114S phage particles, implying that the 108S material is a precursor of phage particles. A model that proposes possible functions for the products of phi X174 genes A, B, C, D, F, and G during viral replication and phage maturation is described.     

The expressive psychopathology of the Japanese poet, Sakutaro Hagiwara

Using reaggregating rat brain cell cultures at two different stages of differentiation, we examined the biochemical effects of a 10-day treatment with nanomolar concentrations of methylmercuric chloride (monomethylmercury), in the presence or absence of promoters of hydroxyl radical formation (10 microM copper sulphate plus 100 microM ascorbate). A decrease in total protein content accounted for the general cytotoxicity of these compounds, whereas selective effects were assessed by determining the activities of cell type-specific enzymes. Methylmercury, up to 100 nM, as well as the copper ascorbate mixture, when applied separately, induced no general cytotoxicity, and only slight effects on neuronal parameters. However, when applying 100 nM methylmercury and the copper-ascorbate mixture together, a drastic decrease in neuronal and glial parameters was found. Under these conditions, the content of reactive oxygen species, assessed by 2',7'-dichlorofluorescin oxidation, increased greatly, while the activities of antioxidant enzymes decreased. In the presence of copper and ascorbate, differentiated cultures appeared more resistant than immature ones to low methylmercury concentrations (1-10 mM), but did undergo similar changes in both cell type-specific and antioxidant enzyme activities at 100 nM methylmercury. These results suggest that in prooxidant conditions low doses of mercury can become much more deleterious for the central nervous system.     

High-power CO2 laser-MIG hybrid welding for increased gap tolerance. Hybrid weldability of thick steel plates with a square groove

High power enhancement of laser processors has recently led to laser welding being used for the joining of thick steel plates. For example, the literature includes a study on the practical application of a 45 kW CO₂ laser for the welding of thick steel plates,¹ although few such applications have thus far been documented. The limited application of lasers to welding of thick steel plates is attributable to the narrow gap tolerance provided and the small laser beam diameter that leads to unacceptable welding defects, such as underfills, melt-through, and porosities.     

Resection of malignant fibrous histiocytoma invading the thoracic aorta

We report a case of surgically resected malignant fibrous histiocytoma which arose in the posterior mediastinum. Tumor removal with the required sufficient-margin and the resection of the affected thoracic aorta, led to flaccid paraplegia below the tenth thoracic level. This patient is now surviving with no evidence of recurrence at 42 months after the operation. Although malignant fibrous histiocytoma in the thorax generally shows a poor prognosis, this patient with complete resection could have a relatively long survival.