This paper deals with elastic and elastic-plastic singular fields around a crack-tip in particulate-reinforced composites with debonding damage of particle-matrix interface. Numerical analyses are carried out on a crack-tip field in elastic-matrix and elastic-plastic-matrix composites reinforced with elastic particles, using a finite element method developed based on an incremental damage theory of particulate-reinforced composites. A particle volume fraction and interfacial strength between particles and matrix of the composites are parametrically changed. In the elastic-matrix composites, a unique elastic singular field is created on the complete damage zone in the vicinity of a crack-tip in addition to the conventional elastic singular field on the no damage zone. The macroscopic stress level around a crack-tip is reduced by the debonding damage while the microscopic stress level of the matrix remains unchanged. In the elasticplastic-matrix composites, the damage zone develops in addition to the plastic zone due to matrix plasticity, and both the macroscopic and microscopic stress revels around a crack-tip are reduced by the debonding damage. It is concluded from the numerical results that the toughening due to damage could be expected in the elastic-plastic-matrix composites, while it is questionable in the elastic-matrix composites.

The groin flap is one of the most usable flaps. It provides a large amount of skin coverage with an easily concealed donor site. However, when the flap is used to reconstruct areas of the neck, hand, or foot, a secondary procedure for defatting is usually necessary. Thinner flaps are thought to be more useful in these areas. We present an anatomical study of the thin groin flap, including its dissection and defatting, and 12 clinical cases using the thin groin flap for neck (n = 7), foot (n = 4), and scalp (n = 1) reconstruction. The largest successful flap measured 13 x 30 cm. Eight flaps survived completely, two had partial necrosis, and two had total necrosis. Complications were thought to be caused by dissection around the pedicle. Meticulous dissection and thinning are required to create the thin groin flap. Excellent aesthetic results requiring no secondary defatting procedures are possible with this new thin groin flap.

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High temperature deformation and fracture of the Al-Mg-Mn sheet consisting with the coarse-grained surface and the fine-grained center layers have been investigated. Such a microstructure was produced by the continuous cyclic bending (CCB) and the subsequent annealing. The elongation to failure has a peak value at 713 K at initial strain rates of 5.6 × 10 −4 s −1 and 5.6 × 10 −3 s −1 in both of as-received sample (0P) with fine grains and CCBent and annealed one (20P A) with the coarse and the fine grains in spite of different microstructures. The m value decreases for 20P A and increases for 0P with increasing temperature. However, the increase of the m value is not correspondent to the change in the elongation. Deformation mechanism is discussed with activation energy. The SEM micrographs of original surfaces of tensile specimen deformed to failure reveal that at the relatively high temperatures many cracks are formed inside the coarse grains. The features of fractured surface for the 20P A sample reflect the coarse-and the fine-grained layers faithfully.

Reduction of manganese dioxide is demonstrated for an in vitro ferrireductase system that includes NADPHdependent ferrireductase and the iron-binding compound (IBC) isolated from the white-rot fungus Phanerochaete sordida YK-624. The Fe(II)-IBC complex was more effective in reducing manganese dioxide to Mn(II) than were complexes of Fe(II) and organic acids of low molecular weight such as nitrilotriacetate, although IBC also reduced manganese dioxide to Mn(II) in the absence of Fe(II). The generated Fe(III)-IBC complex was a better substrate for NADPH-dependent ferrireductase than were other ferric chelates, suggesting that the Fe(III)-IBC complex is reduced to an Fe(II) complex by NADPH-dependent ferrireductase. Moreover, production of the Fe(III)-IBC complex by the reduction of manganese dioxide in a reaction system containing Fe(II) and IBC was observed to be coupled to reduction of the Fe(III)-IBC complex by NADPH-dependent ferrireductase. These results indicate that the ferrireductase system of P. sordida YK-624 plays an important role in the reduction of manganese dioxide, which is necessary for the production and function of manganese peroxidase.