• Proceedings of the Korean Magnestics Society Conference
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• 2010.06a
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• pp.79-79
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• 2010

Semimetallic bismuth (Bi) has been extensively investigated over the last decade since it exhibits very intriguing transport properties due to their highly anisotropic Fermi surface, low carrier concentration, long carrier mean free path l, and small effective carrier mass $m^*$. In particular, the great interest in Bi nanowires lies in the development of nanowire fabrication methods and the opportunity for exploring novel low-dimensional phenomena as well as practical application such as thermoelectricity[1]. In this work, we introduce a self-assembled interconnection of nanostructures produced by an on-film formation of nanowires (OFF-ON) method in order to form a highly ohmic Bi nanobridge. A Bi thin film was first deposited on a thermally oxidized Si (100) substrate at a rate of $40\;{\AA}/s$ by radio frequency (RF) sputtering at 300 K. The sputter system was kept in an ultra high vacuum (UHV) of $10^{-6}$ Torr before deposition, and sputtering was performed under an Ar gas pressure of 2m Torr for 180s. For the lateral growth of Bi nanowires, we sputtered a thin Cr (or $SiO_2$) layer on top of the Bi film. The Bi thin films were subsequently put into a custom-made vacuum furnace for thermal annealing to grow Bi nanowires by the OFF-ON method. After thermal annealing, the Bi nanowires cannot be pushed out from the topside of the Bi films due to the Cr (or $SiO_2$) layer. Instead, Bi nanowires grow laterally as a mean s of releasing the compressive stress. We fabricated a self-assembled Bi nanobridge (d=192 nm) device in-situ using OFF-ON through annealing at $250^{\circ}C$ for 10hours. From I-V measurements taken on the Bi nanobridge device, contacts to the nanobridge were found highly ohmic. The quality of the Bi nanobridge was also proved by the high MR of 123% obtained from transverse MR measurements. These results manifest the possibility of self-assembled nanowire interconnection between various nanostructures for a variety of applications and provide a simple device fabrication method to investigate transport properties on nanowires without complex patterning and etching processes.

• The Korean Journal of Pesticide Science
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• v.3 no.1
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• pp.37-45
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• 1999

Dicamba (3,6-dichloro-o-anisic acid) granular formulations for controlled release (DGFCRs) were prepared with biodegradable polymers, corn starch and pregelatinized starch, to minimize harmful side effects, extend weed control performance, and control the releasing rate of the active ingredient. Physico-chemical properties and biological activity of DGFCRs were studied. Six different granules were formulated by applying two processes, granulation and extrusion. Formulation efficiencies of active ingredient (A.I.) in the granules prepared by granulating and extruding were $90.0{\sim}96.3%$. Incorporation ratios of A.I. in the granules prepared by granulating and extruding showed $89.5{\sim}94.5%$ and $46.7{\sim}82.0%$, respectively. The highest swellability was DG-2 formulation prepared with corn starch. Whereas, the lowest floatability in water was DG-2 formulation, while the highest one was DG-1 formulation prepared with pregelatinized starch, Miragel 463. The degradation rates of dicamba in the granules under the elevated temperature of $50^{\circ}C$ were less than 5% for DG-1 and DG-2 formulations even after 90 days, meanwhile, those of DE-1 formulations prepared with pregelatinized starch, Mirasperse, were more than 5%. The release rates of A.I. from the granules into water under a static condition were about 100% after 2 weeks. Weeding effects of the granules on broad leaf weeds tested in greenhouse were more than 90% after 30 days.

• Journal of Life Science
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• v.27 no.10
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• pp.1097-1103
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• 2017

For the artificial induction of the sexual maturation of Anguilla japonica, salmon pituitary extract (SPE) is continuously injected into females, and the eggs obtained from artificial sexual maturation are artificially fertilized with sperms and hatched. However, repeated injection of SPE in the abdominal cavity causes tremendous stress in females, which may prevent their complete sexual maturation and reduce the immune system function, ultimately resulting in death. In addition, the poor quality of the ovulated eggs can reduce the hatching and survival rate of larvae. In the present study, sexual maturation of females was induced by inserting an osmotic (OS) pump containing hormone analogs known to effectively induce sexual maturation into the abdominal cavity of female eels, and the effect of the OS pump on the induced sexual maturation was investigated. Our study results showed that the gonadosomatic index (GSI) was significantly higher in the fish subjected to SPE injection than those subjected to human chorionic gonadotropin (hCG), gonadotropin-releasing hormone analog (GnRHa), and methyl testosterone (MT) injections, either separately or in combination. In addition, a histological analysis showed that the oocytes in the SPE OS pump groups were more mature (entered the nuclear shift stage) than those in the other groups. These results suggest that an osmotic pump containing hormone analogs can be used to induce sexual maturation in female A. japonica artificially.

• Korean Journal of Food Science and Technology
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• v.35 no.3
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• pp.519-526
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• 2003

Pancreatic lipase and ${\alpha}$-amylase inhibitory activities in purified extracts of pumpkin and job's tear were studied. Pancreatic lipase inhibitory activity was determined by measuring the rate of releasing oleic acid from triolein, and ${\alpha}$-amylase inhibitory activity was determined by iodometric method. The extracts of pumpkin and job's tear were purified using silica gel and C-18 gel column chromatographies. Treatment of pumpkin extract $(120\;{\mu}g/mL)$ in 3T3-L1 preadipocyte decreased differentiation about 95% and blocked accumulation of lipid. Body weights of rats fed high-fat diet containing dietary supplement decreased about 13% as compared with those fed only highfat diet. These results revealed dietary supplement is a good obesity-reducing material for decreasing lipid and carbohydrate absorptions.

• Food Science and Preservation
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• v.9 no.2
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• pp.212-220
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• 2002

Spray drying was used a means for microencapsulation of Aster scaber and Aster glehni. The optimum conditions of spray drying were found to be 210$^{\circ}C$ for the inlet temperature and 5 $m\ell$/min for the feeding rate. The color difference decreased by 12∼25 % far the herb extracts depending on storage temperatures. With an increase in storage temperature, color of the control changed considerably compared to microencapsulated powders. This is due to the fact that wall materials minimized effect of oxygen on the herb extracts. Microencapsulated powders in the amounts of 50 ppm and 250 ppm added to hydrogenated soybean oils led to lower acid values and conjugated diene values during 6 day storage. Compared to the control, the herb extracts displayed 16∼48% increase in antioxidation effect, while the microencapsulated powders exhibited 46∼88% increase. Extracts also showed lower conjugated dienoic acid contents than those of the control. Although antioxidation effect of the microencapsulated powders did not prevail on the significant level in the early stage of storage of oils tested, it became predominant after one week of storage as wall materials were gradually degraded under the high temperature thereby releasing core material from the microcapsule.

• Clinical and Experimental Reproductive Medicine
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• v.26 no.3
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• pp.355-362
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• 1999

Objective: This study was performed to compare the clinical response to controlled ovarian hyperstimulation (COH) of in vitro fertilization and embryo transfer (IVF-ET) according to the size of baseline ovarian cyst. Method: From February 1992 to March 1999, a retrospective analysis was done of 272 cases who underwent COH using mid-luteal phase long protocol of gonadotropin-releasing hormone agonist (GnRH-a) for IVF-ET. These cases were divided into four group; group 1 (n=63) had cysts with mean diameters between 20.0 and 29.0 mm on their baseline ultrasound on cycle day 3, group 2 (n=57, $30.0{\sim}49.0mm$), group 3 (n=68, >50.0 mm) and control group (n=84). Cases were excluded according to the following criteria; pure male factor infertility, the presence of only one ovary, high CA-125 level and previous endometriosis. Results: There were no statistically significant differences between cases with baseline ovarian cyst <50.0 mm in diameter and control group in any of the parameters. However, cases with baseline ovarian cyst>50.0 mm in mean diameter needed more amount of human menopausal gonadotropin (hMG), showed significantly lower estradiol ($E_2$) level, the number of follicle >15.0 mm on the day of human chorionic gonadotropin (hCG) administration, the number of oocytes retrieved, the number of mature oocytes, and pregnancy rate compared with control group. Conclusion: This study suggests that cases with baseline ovarian cyst <50.0 mm in diameter do not adversely impact on IVF-ET outcome. However, cases with baseline ovarian cyst >50.0 mm in diameter had adverse effects on various parameters. Therefore, to improve the outcome of IVF-ET in these cases, ovarian cyst aspiration prior to initiating COH may be required.

• Clinical and Experimental Reproductive Medicine
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• v.21 no.3
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• pp.233-240
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• 1994

This study was conducted to compare the endocrine milieu, and pregnancy rates in In Vitro Fertilization and Embryo Transfer(IVF-ET) program employing combined with gonadotropin releasing hormone agonist(GnRH-a) and pergonal(LH 75lU+FSH 75lU) when either human chorionic gonadotropin(HCG) or progesterone were used for luteal phase support. A total number of 40 IVF-ET treatment cycles were prospectively studied. Ovarian hyperstimulation method was modified ultrashort protocol using GnRH-a. All patients started Decapeptyl at menstrual cycle day # 2, and HMG was started at # 3 days. When leading follicle was ${\geqq}$18mm or at least two follicles were ${\geqq}$14mm in diameter, HCG 10000lU intramuscularly was injected. After 36 hours HCG administration, oocytes were retrieved as usual guided by transvaginal ultrasound. Embryo were transfered 36-48 hours later. The patient's cycles were prospectively randomized to receive HCG(20cycles) or Progesterone (20cycles) for luteal support. The progesterone group received 25mg 1M starting from the day of ET. The HCG group received 1500IU 1M. on days 0, +2, +5 after ET. Estadiol($E_2$) and Progesterone($P_4$) were measured on the day of oocyte aspiration, ET day, and every 6 days thereafter. Results were follows as; 1. Estradiol, progesterone and LH levels on the day of HCG trigger, retrieved oocytes and number of transfered embryo were not significantly different in both groups. 2. On the day of aspiration and embryo transfered day, $E_2$, $P_4$ level were significantly higher in progesterone group than HCG group(p<0.01). 3. $E_2$, $P_4$ level on 6 days after ET were significantly higher in progesterone group than HCG group(p<0.01). But, $P_4/E_2$ ratio was not different in both groups. 4. $E_2$, $P_4$ level 12 days after ET were decreased abruptly in both groups and higher hormonal level appeared in HCG group(P<0.01). 5. The total pregnancy rate in the HCG group was 40% (8/20) and in the progesterone group 15%(3/20). 6. Comparing the pregnant and nonpregnant cases progesterone group was not different the hormonal status. In HCG group, pregnant cases appeared in higher $P_4$, $P_4/E_2$ ratio than nonpregnanct cases(P<0.01).

• Polymer(Korea)
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• v.33 no.4
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• pp.389-395
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• 2009

To develop the carrier of hydrophobic antifungal agents based on low molecular weight water-soluble chitosan (LMWSC), LMWSC was chemically modified with deoxycholic acid (DA) which is one of the bile acid as a hydrophobic group. The nanoparticles (WSCDA) using DA conjugated LMWSC were characterized using dynamic light scattering (DLS) and transmittance electron microscope (TEM). The particle size of WSCDA ranged from 250 to 350 nm and increased with the number of DA substitution. The loaded itraconazole as an antifungal agent WSCDA nanoparticles (WSCDA-ITCN) were prepared by solvent evaporation method. The drug content and the loading efficiency were investigated approximately $9{\sim}10%$ and $61{\sim}68%$ by UV spectrophotometer, respectively. The release of drug from nanoparticles was slow and showed sustained release characteristics. Based on the results of release study that the higher DA contents in WSCDA, the slower the releasing rate, the WSCDA-ITCN could be used as an excellent antifungal agent.

• Current Research on Agriculture and Life Sciences
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• v.2
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• pp.15-22
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• 1984

This study was conducted to identify the enzyme treatment time, enzyme concentration and plant growth condition for isolation of potato mesopyll, it was also performed to determine the adquate sucrose molarity on purification of protoplasts and to investigate the incubation time, PEG concentration and DMSO effect for potato-petunia protoplast fusion. The results were summarized as follows: The optimal time of incubation in enzyme solution was 3 - 4 hours and high humidity and low light intensity made plants more effective to protoplast releasing enzymes. Our experimental results showed that the pectolyase Y-23 was an ideal agent for isolation from mesophyll cultured in vitro compared with macerozyme. The enzyme solution with 0.5 % macerozyme and 2 % cellulase was very effective and the purity of healthy protoplast was better in 0.4 and 0.5 M sucrose than in others. It was revealed that the rate of potato-petunia fusion according to the incubation time with PEG was effective at 30 min incubation and percentage of protoplast aggregation was increased by high molecular weight and concentration of PEG. Percentage of potato-petunia protoplast heteroplasmic aggregation was increased by 4 to 16 % in PEG 6000 compared with PEG 4000 and PEG 1500. Addition of 5 to 10 % DMSO to the PEG solution increased to the heteroplasmic aggregation of potato-petunia from 2 to 4 %.

• Journal of Korea Port Economic Association
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• v.37 no.1
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• pp.1-18
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• 2021

A coastal marine ranching project in Uleungdo had been conducted for 5 years from 2013 to 2017 with investment costs of 5 billion won, for the special purpose of the deployment of artificial reefs, the release of young fishes. The paper focuses on an ex-post analysis of the economic feasibility for the project after completing the project, which is apart from a preliminary viability. For economic analysis, the economic benefits are derived from direct benefits including increasing effects of fisheries income and saving effects of harvesting costs, and indirect benefits including increasing effects of recreational fishing and preservation effects of coastal marine ecosystems while economic costs include releasing and purchasing costs of artificial reef and juvenile fish, R&D costs, maintenance costs and harvesting costs. The result shows that the project should not be accepted according to NPV=-0.125 billion won, IRR=4.5% and B/C ratio=0.98 under Scenario 1 which considers direct benefits and indirect benefits excluding the preservation values, while the project should be accepted under Scenario 2 indicating NPV=30.9 billion won, IRR=11.3% and B/C ratio=1.49 which considers the direct benefits as well as the indirect ones including the preservation values, based on 4.5% of the social rate of discount.