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한근희,김용철,류정인,선도원,민병무 한국화학공학회 2004 Korean Chemical Engineering Research(HWAHAK KONGHA Vol.42 No.2
대부분의 유동층 연소장치에서 충물질과 비산된 입자에 의한 충내 전열관과 water wall의 전열관 표면의 마모는 계속적으로 골칫거리가 되고 있다. 본 연구는 단면적이 0.15m×0.30m인 상온유동층장치에서 마모하기 쉬운 아크릴 관을 사용하여 유동층에 파묻힌 전열관에 대하여 유동조건과 전열관의 배열효과에 대한 실험적인 연구를 나타냈다. 유동층의 단면적은 0.15m×0.30m이고 높이는 1.0m이다. 층물질은 강모래 평균입도 0.73, 1.24mm의 두 가지와, 평균입도 0.9mm의 무연탄 희재를 사용하였다. 유동층 높이는 0.45m이었다. 마모실험은 조건마다 100시간동안 유동화속도 1.2-1.8m/s 까지 변화시켜 수행하였다. 실험결과 마모율은 유동화속도가 증가할수록 증가하였고, 공기분배기로부터 떨어진 거리가 증가할수록 증가하였다. 그리고 공기분배기로부터 높이 0.6m의 비산영역에 위치한 전열관에 심한 마모를 나타냈다. 전열관의 원주방향에 대한 마모경향은 다른 부분과 비교하여 시계방향으로 4시 방향에서 8시 방향까지 심한 마모가 나타났고, 특히 5시 방향과 7시 방향은 심한 마모를 보였다. Erosion of in-bed tubes and water wall heat transfer surfaces by bed materials and elutriated particles have persistently plagued most fluidized bed combustion (FBC) systems. This papere presents a systematic experimental study of the effects of tube arrangement and flow condition on embedded tube erosion by using erosion-prone acrylic cylinders in a 0.15m×0.30m bench-scale cold fluidized bed. The bed material was two different sizes of river sand and anthracite ash with the average diameter of 0.73, 1.24, 0.90㎜, respectively. The static bed height was 0.45m. Erosion test was performed with the variation of fluidization velocity of 1.2 to 1.8m/s for 100 hours per set. The result shows that the erosion rate increased with fluidizing velocity, with distance from the distributor. The erosion was severe at the tube located in the splash zone of 60㎝ above the distributor. The trend with radial direction shows severe erosion at the 4-8 o'clock clockwise compare to other area, especially 5 and 7 o'clock clockwise.
Yong-Nan Xu,Sang-Jun Uhm,Bon-Chul Koo,Mo-Sun Kwon,Ji-Yeol Roh,Jung-Seok Yang,Hyun-Yong Choi,Young-Tae Heo,Xiang-Shun Cui,Joon-Ho Yoon,Dae-Hwan Ko,Teoan Kim,Nam-Hyung Kim 한국동물생명공학회(구 한국동물번식학회) 2013 Reproductive & Developmental Biology(Supplement) Vol.37 No.2s
The potential benefits of generating and using transgenic cattle range from im-provements in agriculture to the production of large quantities of pharmaceutically rele-vant proteins. Previous studies have attempted to produce transgenic cattle and other livestock by pronuclear injection and somatic cell nuclear transfer, but these approa-ches have been largely ineffective; however, a third approach, lentivirus-mediated trans-genesis, has successfully produced transgenic livestock. In this study, we generated transgenic (TG) Korean native cattle using perivitelline space injection of viral vectors, which expressed enhanced green fluorescent protein (EGFP) systemically. Two different types of lentiviral vectors derived from feline immunodeficiency virus (FIV) and human immunodeficiency virus (HIV) carrying EGFP were injected into the perivitelline space of MII oocytes. EGFP expression at 8-cell stage was significantly higher in the FIV group compared to the HIV group (47.5±2.2% vs. 22.9±2.9%). Eight- cell embryos that expressed EGFP were cultured into blastocysts and then transferred into 40 heifers. Ten heifers were successfully impregnated and delivered 10 healthy calves. All of these calves expressed EGFP as detected by in vivo imaging, PCR and Southern blotting. In addition, we established an EGFP-expressing cell line from TG calves, which was followed by nuclear transfer (NT). Recloned 8-cell embryos also expressed EGFP, and there were no differences in the rates of fusion, cleavage and development between cells derived from TG- and non-TG calves, which were subsequently used for NT. These results illustrate that FIV-based lentiviruses are useful for the production of TG cattle. Moreover, our established EGFP cell line can be used for additional studies that involve induced pluripotent stem cells.
Hyperglycemia Influences Apoptosis and Autophagy in Porcine Parthenotes Developing In Vitro
Xu, Yong-Nan,Li, Ying-Hua,Lee, Sung Hyun,Kwon, Jung-Woo,Lee, Seul Ki,Heo, Young-Tae,Cui, Xiang-Shun,Kim, Nam-Hyung The Korean Society of Animal Reproduction 2013 Reproductive & developmental biology Vol.37 No.2
The objective of this study was to examine the effects of high concentrations of glucose on porcine parthenotes developing in vitro. Addition of 55 mM glucose to the culture medium of embryos at the four-cell-stage significantly inhibited blastocyst formation, resulting in fewer cells in blastocyst-stage embryos and increased levels of apoptosis and autophagy compared to control. Quantitative reverse transcriptase (RT) PCR analysis revealed that the expression of pro-apoptotic genes (Caspase 3, Bax and Bak) and autophagy genes (Atg6 and Atg8/Lc3) were increased significantly by the addition of 55 mM glucose to the culture medium compared to control. MitoTracker Green fluorescence revealed a decrease in the overall mitochondrial mass compared to control. However, the addition of 55 mM glucose had no effect on mRNA expression of the nuclear DNA-encoded mitochondrial-related genes, cytochrome oxidase (Cox) 5a, Cox5b and Cox6b1. These results suggest that hyperglycemia reduced the mitochondrial content of porcine embryos developing in vitro and that this may hinder embryonic development to the blastocyst stage and embryo quality by increasing apoptosis and autophagy in these embryos.
Histone deacetylase inhibitor trichostatin A affects porcine oocyte maturation in vitro
Jin, Yong-Xun,Zhao, Ming-Hui,Zheng, Zhong,Kwon, Jung-Suk,Lee, Seul-Ki,Cui, Xiang-Shun,Kim, Nam-Hyung CSIRO Publishing 2014 Reproduction, fertility, and development Vol.26 No.6
<P> Previous studies show that porcine oocyte aging resulting from asynchronised IVM impairs embryo developmental competence. In the present study we investigated whether trichostatin A (TSA; an inhibitor of histone deacetylation) prolongs the maturation time and prevents the aging of oocytes. Porcine oocytes were cultured in medium containing increasing concentrations of TSA (300 nM) for 24, 44 or 64 h. The percentage of oocytes that underwent germinal vesicle breakdown was significantly lower in the TSA-treated group (300 nM) than in the control group. TSA did not affect oocyte quality at MII based on levels of maturation-promoting factor, the phosphorylation status of mitogen-activated protein kinase or histone H3K9 acetylation analysis. We also compared the preimplantation developmental competence and the viability of pathenogenetic embryos treated with 100 nM TSA for 24 h and then continuously cultured for another 24 h in TSA free condition. No significant differences were observed for either parameter between the TSA-treated and control groups. These results indicate that TSA prolongs the IVM of porcine oocytes but that oocyte quality and aging are not affected. These findings provide a feasible option by which to adjust the initiation time of downstream experiments based on porcine matured oocytes. </P>
Xu, Yong-Nan,Uhm, Sang-Jun,Koo, Bon-Chul,Kwon, Mo-Sun,Roh, Ji-Yeol,Yang, Jung-Seok,Choi, Hyun-Yong,Heo, Young-Tae,Cui, Xiang-Shun,Yoon, Joon-Ho,Ko, Dae-Hwan,Kim, Teoan,Kim, Nam-Hyung Science press ; Elsevier 2013 Journal of genetics and genomics Vol.40 No.1
<P>The potential benefits of generating and using transgenic cattle range from improvements in agriculture to the production of large quantities of pharmaceutically relevant proteins. Previous studies have attempted to produce transgenic cattle and other livestock by pronuclear injection and somatic cell nuclear transfer, but these approaches have been largely ineffective; however, a third approach, lentivirus-mediated transgenesis, has successfully produced transgenic livestock. In this study, we generated transgenic (TG) Korean native cattle using perivitelline space injection of viral vectors, which expressed enhanced green fluorescent protein (EGFP) systemically. Two different types of lentiviral vectors derived from feline immunodeficiency virus (FIV) and human immunodeficiency virus (HIV) carrying EGFP were injected into the perivitelline space of MII oocytes. EGFP expression at 8-cell stage was significantly higher in the FIV group compared to the HIV group (47.5%2.2% v.s. 22.9%2.9%). Eight-cell embryos that expressed EGFP were cultured into blastocysts and then transferred into 40 heifers. Ten heifers were successfully impregnated and delivered 10 healthy calves. All of these calves expressed EGFP as detected by in?vivo imaging, PCR and Southern blotting. In addition, we established an EGFP-expressing cell line from TG calves, which was followed by nuclear transfer (NT). Recloned 8-cell embryos also expressed EGFP, and there were no differences in the rates of fusion, cleavage and development between cells derived from TG and non-TG calves, which were subsequently used for NT. These results illustrate that FIV-based lentiviruses are useful for the production of TG cattle. Moreover, our established EGFP cell line can be used for additional studies that involve induced pluripotent stem cells.</P>