• Proceedings of the Korean Society of Developmental Biology Conference
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• 1998.07a
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• pp.12-18
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• 1998

Tremendous progress has been made over the past quarter-century studying the genetics of gametogenesis and the resulting gametes and embryos. Studies merging molecular techniques and conventional cytogenetics are now beginning to bridge the gap between what we have learned about the meiotic process in males and females and what we know of the mitotic chromosomes of zygotes. Numerical abnormalities in sperm, oocytes and embryo can now diagnosed by fluorescence in situ hybridization (FISH). "At risk" couples can, therefore, have only unaffected embryos replaced in the sterus and avoid the possibility of terminating a pregnancy that might only be diagnosed as affected later gestation. Single-cell genetic analysis has also provided powerful tools for studying genetic defects arising during early human development. Recent studies of sperms, oocytes and cleavage-stage human embryos have revealed an unexpectedly high incidence. These genetic abnormalities are likely to contribute to early pregnancy loss and have important implications for improving pregnancy rates in infertile couples by assisted reproduction. The widespread use of preimplantation genetic diagnosis (PGD) awaits further documentatio of safety and accuracy. Other issues also must be addressed. First, the ethical issues regarding germ cell and embryo screening must be addressed including what diseases are serious enough to warrant the procedure. Another concern is the use of this technology for non-genetic disorders such as gender selection. Finally, the experimental nature of these procedure must continually be discussed with patients, and long-term follow-up studies must be undertaken. Development of more accurate and less expensive assays coupled with improved assisted reproductive technology success rates may make PGD a more widely use clinical tool. The future awaits these development.velopment.

• KOMUNHWA
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• no.93
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• pp.153-184
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• 2019

The Yunggimuntogi(Treasure No. 597) has been known to be recovered at Yeongseondong Shell Mounds, Busan in 1933 during the Japanese colonial period. This artifact is characterized by a short spout attached to one side of the mouth rim as well as a V-shaped clay stripe on the upper body part, which is the only earthenware designated as national cultural heritage from the prehistoric period. In order to prepare for the earthquakes that have recently become more frequent, this study has precisely diagnosed the conservation status and stabilized the artifact through scientific conservation treatment. As a result of the precise diagnosis of the preservation status, cracks and losses were observed in the spout, the mouth rim, and the base. In some portion of the raised pattern decorations, loss of fine pieces raised concerns over the secondary damage. The C·T image analysis has shown that the earthenware had been once glued and restored from dozens of broken pieces. From the sites restored in the past, the peeling of surface colored layer and the fine cracks between the restoration material and the earthenware clay were observed due to the aging of the restoration material. Furthermore, the inherent color and texture of the earthenware was altered by excessive color matching. The damaged and restored sites were concentrated on the left side, the rear side, and the right side. The damages were more severe on the base than the body portion. In the past, gypsum(CaSO4) had been mainly used as restoration material, and synthetic resin had been partially used for joining and reinforcing the pieces. On the surface of the restoration sites, it is presumed that lead chromate(PbCrO4) yellow modern pigment was used for color matching. The precise diagnosis has revealed that the restoration material in the past has been stabilized by interlocking with the earthenware clay for a long time. Therefore, in this conservation treatment, the coloring layer of the excessively painted surface was washed to recover the original color and texture of the earthenware, and the physically vulnerable parts of the sites restored in the past were mainly targeted for joining and restoration. The conservation treatment has proceeded in the order of cleaning, joining and restoration, and color matching, and materials and methods suitable for the artifacts were selected and applied through a preliminary experiment. The survey on conservation status before the treatment as well as the conservation treatment process have been systematically recorded and documented to provide basic data for further continuous conservation and maintenance by collecting institutions.