In the aim of tissue regeneration of an alveolar bone, we developed three-dimensional fabric structural composite scaffolds using a bioabsorbable polymer. This scaffold consists of a polylactic acid (PLLA) resin fiber and a 75/25 poly L-lactide-co-glycolide (PLGA) copolymer resin coat. Scaffold is woven on a new-type of three-dimensional loom, has high porosity (89%) and continuous hole. The compressive rigidity and collapse strength of scaffold are increased due to the resin bonding between fiber intersections. The strength of scaffold that did a dip to phosphoric acid buffer solution (PBS) decreased in half due to the hydrolysis in six weeks. Mouse osteoblast-like cells (MC3T3-E1) were seeded onto the scaffolds and cultured in vitro for six weeks. The cells proliferated during in culture and formed a space-filling tissue between polymer fibers. Bone regenerative messenger ALP/DNA levels remained high compared with those one of culture dish. Mineralization of the deposited collagen on scaffold was initially observed at four weeks. Culture of cell on scaffold constructs for six weeks led to formation of a bone tissue.
I.Introduction.The notion of non-degenerate divisors on an abelian variety was introduced first by Morikawa [2]Il, then after Weil proved that if Xis a non-digenerate divisor on an abelian variety, then the complete linear system / mX / is ample 2 l for a sufficiently large m [6].The latter property of divisors can be transferred to any variety and we shall call, in this paper, a divisor X on an algebraic variety "non-degenerate", if I mX I is ample and has no fixed component for a sufficiently large m.Now we ask how one can distinguish the class of non-degenerate divisors among the set of divisors.For this purpose we shall introduce the notion of (p)-cycles on a non-singular variety vn.Let X be an r-dimensional cycle on V.If the Kronecker index (X.Y) is positive for all positive cycles Y of codimension r, we shall call X a (p)-cycle.The main theorem in this paper asserts that if Vis a non-singular surface, any (p)-divisor is non-degenerate and conversely.On the other hand a nondegenerate divisor is a (p)-divisor and it is seen easily that any positive (p)divisor is non-degenerate on an abelian variety 3 l_ It would be interesting to investigate the relation between these two notions in general situation. Summary of known results. (A)Let F be a complete non-singular surface and let X be a divisor on F. Let2(X) be the sheaf of germs of rational
In polypropylene resin matrix glass fiber injection molding composite materials, surface of fibers is usually treated by coupling and/or sizing agent and resin is modified by malefic acid because mean fiber length is shorter than their critical length, and interfacial adhesion strength between fibers and resin is low. Therefore, fiber strength has not been utilized completely in these composite materials. In the present study, we propose a method to improve the interfacial adhesion strength by increasing shear strength between fibers and resin, which can be attained by increasing mixing pressure in kneading machine. Since stress-strain relation of composite materials is affected by surface treatment of fibers, interfacial adhesion strength was evaluated by the average interface shear stress through a visco-elastic model. The effect of mixing pressure was discussed based on the shear stress. For a composite material with no surface treatment of fibers and no resin modification, the interfacial shear strength was higher for higher mixing pressure. On the other hand, for a composite material with the surface treatment and the modification, the effect of mixing pressure on the shear strength was not observed. For these materials, however, higher mixing pressure also contributes the adhesion strength between fibers and resin because fiber length in the materials is longer for higher mixing pressure.
In recent years, fatigue limit estimation based on dissipated energy measurement using infrared thermography has attracted attention in various industries. In this study, fatigue limit estimation based on dissipated energy measurement and conventional fatigue test were conducted the expanded-magnesium alloy type AZ31B. Fatigue limit estimated by dissipated energy measurement was around 95MP to lOOMPa. This value generally coincided with that obtained by conventional 10^7 cycles fatigue test. Relationship between plastic strain energy and dissipated energy was investigated to discuss microstructure transformation. It was found that dissipated energy does not vary linearly with the plastic strain energy. It was considered that energy dissipation for AZ31B is affected by the deformation twins.
In his previous paper [2],2 the author proved a criterion of an ample divisor 3 on a non-singular surface, i. e., a divisor X on a non-singular surface F is ample if and only if (X2) > 0 and X is arithmetically positive.4 In this paper he will prove a generalization of this result to a projective scheme over a field. Originally the author intended to prove this generalization only for a non-singular variety of any dimension, say n. However, in the course of the proof it became necessary to treat the problem on a variety of dimension n-1 with singularities, and then on a scheme of dimension n2. This is the reason why he finally decided to treat the problem on a general projective scheme right from the beginning. The author wishes to express his heartfelt thanks to Professor 0. Zariski and to D. Mumford. Without their encouragement and suggestions this work would not have been done. In this paper we shall make extensive use of notations, terminologies, and the results in Grothendieck's book, flements de G-4ometrie Algebrique, which will be cited as [G]. Most of them will be used freely without any further explanations, except some less fundamental notions. We hope the readers will not find much inconvenience in this way.
