• KOREAN JOURNAL OF CROP SCIENCE
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• v.54 no.4
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• pp.433-440
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• 2009

Korean sweetpotato, Ipomoea batatas, varieties were examined for their flowering response as a fundamental research to improve breeding efficiency by hybridization of this crop. Under 10.0~10.5 hours short day condition, self-rooted plants of three varieties such as Shinmi, Hongmi and Hwangmi flowered sparsely or moderately, and those of fourteen varieties including Eunmi flowered very sparsely. Under 10.6~12.0 hours day length condition, self-rooted plants of three varieties such as Shinmi, Hongmi and Hwangmi flowered very sparsely. Under the day length longer than 12 hours, none of the tested plants flowered. In all the sweetpotato plants grafted on morning glory, flowering occurred with varying degrees by varieties and day lengths. Under 10.0~10.5 hours day length, thirty two varieties including Hongmi flowered moderately or profusely, and one variety such as Mokgye 1 flowered sparsely. Under 10.6~12 hours day length, twenty three varieties including Sinchunmi flowered moderately or profusely, nine varieties including Jeungmi flowered sparsely, and Mokgye 1 didn't flower at all.

• Horticultural Science & Technology
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• v.34 no.5
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• pp.779-789
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• 2016

A total of 33 accessions of pepper (Capsicum spp.), including previously reported and newly discovered sources of resistance to bacterial spot caused by Xanthomonas euvesicatoria, were evaluated for their resistance to bacterial spot. The selected accessions were then grown and their horticultural characteristics were recorded. In a test for hypersensitive resistance (HR) to four races (P1, P3, P7, P8) of the pathogen found in Korea, KC00939 and Chilbok No.2, which carry the Bs2 gene, exhibited a hypersensitive response to all four races, as expected. Chilbok No.3, which carries the Bs3 gene, showed a hypersensitive reaction to race 1 and 7, as expected. KC00939 exhibited a high ASTA color value and tolerance to multiple infections from a viral complex of Cucumber mosaic virus (CMV) and Broad bean wilt virus (BBWV). Thus, this accession represents a promising genetic resource for breeding cultivars with multiple disease resistance and strong red coloration. KC01327, KC01617, KC01015, KC01760, KC01779, KC01137, KC01328, KC01006, KC00127, KC01704, and KC00995 did not exhibit hypersensitivity but showed a high level of general resistance when evaluated by spray inoculation. KC01617, KC01760, KC01779, KC01137, KC01704, and KC01777 are newly identified sources of resistance to bacterial spot. The previously and newly identified sources of resistance to bacterial spot evaluated in this study, including information about their resistance to CMV and BBWV complex in the field, the contents of pungent and sweet taste components, and the color values of dry fruits, will be useful for breeding pepper cultivars with resistance to bacterial spot.

• Clinical and Experimental Reproductive Medicine
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• v.33 no.3
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• pp.171-178
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• 2006

Objective: Human embryonic stem (ES) cells have a great potential in regenerative medicine and tissue engineering. The human ES cells could be differentiated into specific cell types by treatments of growth factors and alterations of gene expressions. However, the efficacy of guided differentiation and isolation of specific cells are still low. In this study, we characterized isolated cells from differentiated human ES cells by magnetic activated cell sorting (MACS) system using specific antibodies to cell surface markers. Methods: The undifferentiated hES cells (Miz-hESC4) were sub-cultured by mechanical isolation of colonies and embryoid bodies were spontaneously differentiated with DMEM containing 10% FBS for 2 weeks. The differentiated cells were isolated to positive and negative cells with MACS system using CD34, human epithelial antigen (HEA) and human fibroblast (HFB) antibodies, respectively. Observation of morphological changes and analysis of marker genes expression were performed during further culture of MACS isolated cells for 4 weeks. Results: Morphology of the CD34 positive cells was firstly round, and then it was changed to small polygonal shape after further culture. The HEA positive cells showed large polygonal, and the HFB positive spindle shape. In RT-PCR analysis of marker genes, the CD34 and HFB positive cells expressed endodermal and mesodermal genes, and HEA positive cells expressed ectodermal genes such as NESTIN and NF68KD. The marker genes expression pattern of CD34 positive cells changed during the extension of culture time. Conclusion: Our results showed the possibility of successful isolation of specific cells by MACS system from undirected differentiated human ES cells. Thus, MACS system and marker antibodies for specific cell types might be useful for guided differentiation and isolation of specific cells from human ES cells.

• Journal of the Korean Electrochemical Society
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• v.20 no.1
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• pp.7-12
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• 2017

Using a precursor of $LiNi_{0.6}Co_{0.2}Mn_{0.2}O_2$ as a starting material, a surface-modified cathode material was obtained by coating with KCl, where the added KCl reduces residual Li compounds such as $Li_2CO_3$ and LiOH, on the surface. The resulting electrochemical properties were investigated. The amounts of $Li_2CO_3$ and LiOH decreased from 8,464 ppm to 1,639 ppm and from 8,088 ppm to 6,287 ppm, respectively, with 1 wt% KCl added $LiNi_{0.6}Co_{0.2}Mn_{0.2}O_2$ that had been calcined at $800^{\circ}C$. X-ray diffraction results revealed that 1 wt% of KCl added $LiNi_{0.6}Co_{0.2}Mn_{0.2}O_2$ did not affect the parent structure but enhanced the development of hexagonal crystallites. Additionally, the charge transfer resistance ($R_{ct}$) decreased dramatically from $225{\Omega}$ to $99{\Omega}$, and the discharge capacity increased to 182.73mAh/g. Using atomic force microscopy, we observed that the surface area decreased by half because of the exothermic heat released by the Li residues. The reduced surface area protects the cathode material from reacting with the electrolyte and hinders the development of a solid electrolyte interphase (SEI) film on the surface of the oxide particles. Finally, we found that the introduction of KCl into $LiNi_{0.6}Co_{0.2}Mn_{0.2}O_2$ is a very effective method of enhancing the electrochemical properties of this active material by reducing the residual Li. To the best of our knowledge, this report is the first to demonstrate this phenomenon.

• Korean Journal of Agricultural Science
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• v.6 no.1
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• pp.56-64
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• 1979

Two types of fiat-plate collector were designed and constructed for utilizing the solar energy as heating source of red pepper drying. It was performed to investigate the basic factors on using the collectors and the drying effect on various types of red pepper, and the results obtained are summarized as follows. 1. The optimum tilted angles of the collector in Daejeon area were ${\phi}-15^{\circ}$ in summer season and ${\phi}+15^{\circ}$ in winter season when it was adjusted two times per a year: 2. In the conditions during experiment period, average atmospheric temperature and relative humidity were $25.6^{\circ}C$ and 52.6%, respectively, and $42.0^{\circ}C$, 74.2% in the control chamber. The temperature in the drying chamber connected to the water heater was the highest but relative humidity in the chamber connected to the air heater was the lowest among the chambers. 3. The drying velocity of whole red pepper in the chamber connected to the water heater was the fastest as 2.3 times as compared to the whole type on the mat drying followed by air heater and control in decreasing order. The horizontally cut red pepper in the chamber connected to the water heater was dried exceedingly fast among twelve plots. 4. The content of capsaicine as pungent principle and of capsanthine as red pigment in the red pepper were reduced during drying but there were no differences significantly on the drying method, and it could not affect much on the quality of dried product.

• Clinical and Experimental Reproductive Medicine
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• v.34 no.4
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• pp.305-312
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• 2007

Objective: To evaluate the efficacy of split insemination method in treatments for non-male factor infertility. Method: Laboratory and clinical data were collected from 505 cycles of split insemination during 2002$\sim$2005 in our center. The subjects were non-male factor infertility such as endometriosis, tubal, uterine, PCOS and idiopathic infertility without any sperm defects. Retrieved oocytes were randomly divided, and inseminated by conventional IVF or ICSI. Fertilized zygotes were cultured for 2$\sim$5 days to ET date, and surplus zygotes and embryos were frozen for subsequent frozen-thawed ET cycles. Clinical outcomes according to insemination method were compared by statistical analysis. Results: The overall fertilization per retrieved oocytes was significantly higher in ICSI than that of conventional IVF in sibling oocytes (62.5$\pm$22.3% vs 52.9$\pm$28.0%, p<0.01). Total fertilization failure occurred only in 2 of 505 cycles (0.4%) in split insemination cycles. Incidence of fertilization failure and poor fertilization rate less than 30% by ICSI were significantly lower than those of conventional IVF (1.1% and 7.5% vs 8.5% and 22.0%, p<0.01). Delivery rates after transfer of fresh and thawed embryos from split insemination cycles were 40.0% (185/462) and 35.0% (55/157), respectively. There was no significant difference in the implantation and delivery rates of ET with embryos from conventional IVF or ICSI. Conclusion: Taken together, the split insemination method improves poor fertilization rates resulting in successful clinical outcomes and thus could be used for non-male factor infertile couples in human ART program.