We examined the transport of human immunoglobulin G (IgG) subclasses and fusion proteins with the Fc region of human IgG to the egg yolk, after the proteins were injected into a vein of hens. Human ...IgGs were efficiently transported and accumulated into the yolk, whereas the proteins were not detected in the egg white. Among human IgG subclasses, IgG2 was transported most efficiently. Fc-fusion proteins injected were also transported into the yolk. A fusion protein with the Fc region derived from human IgG2 was more efficiently transported into the yolk than the counterpart fusion with the Fc region from human IgG1. This study shows that the recovery of recombinant antibodies and Fc-fusion proteins from the yolk is an effective method in transgenic chicken bioreactors.
A retroviral vector was injected into the heart of developing chicken embryos to determine the best timing for effective gene transduction into the gonads. Transduction efficiency and transgene ...expression were both highest when the viral solution was injected into embryos at stages 14–15 (Hamburger-Hamilton stages), in which primordial germ cells (PGCs) can be found in the blood circulation. This study shows that PGCs in the blood are important targets for gene transfer into the gonads using retroviral vectors.
Machinable ceramics consisting of fluor-phlogpite can be machined with tight tolerance using conventional metal working equipment and tools. In recent years, it was clear that the machining surface ...of these ceramics is formed as a small fracture. The cutting mechanism of precise machining is related to a small fracture mechanism of ceramics. The purpose of this paper is to study the fracture mechanism of machinable ceramics. An investigation into the fracture mechanism was carried out on a newly developed fracture device. The main results obtained are as follows: (1) The cracks for fracture grew roughly in three stages, and then a large AE signal generated. (2) A fracture model for machinable ceramics was suggested using grown-up cracks. (3) The fracture energy of per unit area was estimated to be 40 J/m2.
Machinable ceramics consisting of fluor-phlogopite can be easily machined using conventional metal working equipment and tools. In recent years, ceramic parts require precise machining. The formation ...of cracks has a direct effect upon the machined surface. The purpose of this paper is to study the mechanism of crack propagation in machinable ceramics. The investigation of the behavior of cracks in ceramics was carried out using a simple model of the finite element method (FEM). The main results obtained are as follows: (1) The pattern of crack propagation are type (A) of straight path in the mica and type (B) of detour path to boundary glass and mica. (2) The deflection and the branching of the crack are most influenced with the ratio of the maximum fracture stress of the mica to that of the glass. (3) Assuming that the propagation length of crack is proportional to the fracture energy, this energy of crack type B to type A increases to about 60% with the ratio of propagation length at 1.66 times.
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