Oct4 and Nanog are transcription factors involved in pluripotency of stem cells. In general, Oct4 is up-regulated by Nanog. In previous results, however, Oct4 was differentially regulated by various doses of Nanog in P19 cells. High dose Nanog down-regulated the Oct4 expression. This negative feedback event was performed by DNMT and HDAC through the inhibitor assays (5-AZA-cytidine and trichostatin A). To identify the precise recruited sites for DNMT and HDAC, ChIP assay was performed in differential doses of Nanog. As a result, HDAC1, HDAC2, DNMT3A and Nanog were recruited to CR2, CR3, CR1, and CR4 upon high dose Nanog, respectively. Next, to investigate the differentiation potency of the cells upon high dose Nanog, RT-PCR with specific markers for three germ layers was performed. However, there was no increase for three germ layers in high dose Nanog treated cells except E-cadherin expression. E-cadherin is a specific marker for epithelial cells. Taken together, high dose Nanog induces Oct4 down-regulation and results in differentiating embryonic carcinoma cells to epithelial cell type. These results will be helpful for study on regulation of pluripotency-related genes in embryonic stem cells. * This study was supported by 2012 Post Doctoral Fellowship Program of National Institute of Animal Science, Rural Development Administration, Republic of Korea. This work received grant support from the Agenda Program (No.PJ007577), Rural Development Administration, Republic of Korea.

Unstable Epigenetic reprogramming was DNA methylation, imprinting, RNA silencing, co-valent modifications of histones and remodelling by other chromatin-associated complexes. After fusion with an enucleated oocyte, a differentiated somatic cell can restructure its genetic program and acquire totipotent characteristics. However, these cases happen only with low frequency. primordial germ cells (PGC) was effectively remove of epigenetic modifications in the genetic totipotency which is necessary for the development. The present study was in vitro development of reconstruct PGC NT embryos compared with somatic cell NT embryos. The rate of cleavage did not differ between NT embryos from PGC and somatic cells (87.26 vs 91.36%). However, the rate of development to the blastocyst stage was significantly higher in PGC cell NT than somatic cell NT (31.03 vs 19.27%). PGC from a slightly younger stage of development have succeed to promote normal development of recipient eggs. This difference in results between germ cell and somatic cell nuclear transfers could only be a reflection of intimate differences in their reprograming. These results suggest that PGC NT embryos are significantly higher for the in vitro development. Furthermore, These study may represent an approach towards achieving better production of transgenic animal.

To evaluate parameters influencing on the dust removal of the High Temperature Filter(HTF) system, a computer simulation of fluid dynamics inside the system had been performed. The results showed that the optimum pulse jet periods were 50ms and 90ms for the 1000mm and 1500mm long filter elements respectively. Dust removal effect was very excellent under the pulse jet pressure of 3 bar. But the distance between the pulse jet nozzle and the venturi of a filter element had no meaningful effect on the performance with the variation from 5mm to 10mm. Compared to the dispersion mode of pulse jet, the collective mode of pulse jet flow was preferable in maintaining the pressure inside the system stable.

원자력발전소에서 발생하는 이온교환수지와 가연성잡고체 혼합폐기물을 유리화하기 위하여 유도 가열식 저온용융로를 이용한 실증시험을 수행하였다. 금속 티타늄 고리(Ti-ring)를 이용한 유리의 초기점화에 필요한 에너지는 약 290 kWh로 평가되었다. 혼합폐기물의 투입 중 고주파발생기의 출력은 160∼190 kW로 임피던스는 0.55∼0.65 범위 내에서 안정적으로 유지되었다. 이온교환수지 단독투입 시 보다 가연성잡고체와 혼합 할 경우 CO 발생농도는 1/40 정도로 낮아졌는데, 이는 1.8배 정도 높은 연소에너지를 갖는 가연성잡고체가 혼합폐기물의 완전연소를 유도한 것으로 평가되었다. 혼합폐기물의 공급량에 적당한 최적 산소 버블링에 의해 유리 용탕 내부로의 미연폐기물의 함침은 발생하지 않았으며 유리 용탕은 지속적으로 공정 건전성을 유지하였다. 유리 용탕의 부피가 증가하는 팽창(swelling) 현상 때와 정상 일 때 발생가스를 측정, 비교한 결과 swelling 현상 때는 NO와 같이 환원성 가스의 농도 보다 산화성 기체인 의 농도가 높은 것으로 나타났다. 실증시험에 사용된 이온교환 수지와 가연성잡고체의 각각 투입량은 368kg과 751kg 이었으며, 74 정도의 감용비를 달성하였다.