• Progress in Superconductivity
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• v.10 no.2
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• pp.87-91
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• 2009

Fluorine-doped $SmFeAsO_{1-x}F_x$ single crystals with the nominal value of x=0.2 were grown at $1350-1450^{\circ}C$ under the pressure of 3.3 GPa by using the self-flux method. Plate-shaped single crystals in the range of a few-150 ${\mu}m$ in their lateral size were obtained. The detailed crystal structure was analyzed by using the x-ray diffractometry. Superconducting transition temperature, determined by the resistive transition, of a single crystal was about 49 K with a narrow resistive transition width of ${\sim}1$ K. A relatively sharp transition, a low residual resistivity, and a large residual resistivity ratio compared with those reported for $REFeAsO_{1-x}F_x$(RE=Sm, Nd) single crystals indicate the high quality of our single crystals.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.37 no.2
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• pp.78-84
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• 2000

The Viterbi decoders can be classified into serial Viterbi decoders and parallel Viterbi decoders. Parallel Viterbi decoders can handle higher data rates than serial Viterbl decoders. This paper designs and implements a fully parallel Viterbi decoder for high speed multimedia communications. For high speed operations, the ACS (Add-Compare-Select) module consisting of 64 PEs (Processing Elements) can compute one stage in a clock. In addition, the systolic away structure with 32 pipeline stages is developed for the TB (traceback) module. The implemented Viterbi decoder can support code rates 1/2, 2/3, 3/4, 5/6 and 7/8 using punctured codes. We have developed Verilog HDL models and performed logic synthesis. The 0.6 ${\mu}{\textrm}{m}$ SAMSUNG KG75000 SOG cell library has been used. The implemented Viterbi decoder has about 100,400 gates, and is running at 70 MHz in the worst case simulation.

• Korean Journal of Agricultural Science
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• v.25 no.1
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• pp.118-123
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• 1998

Lasiodiplodia theobrorme is a pathogen of Java black rot on sweet potato. This fungus infects the tuberous root during storage after harvest. Invasion of the fungus results in the expansion of necrosis sites into the tuberous roots. The resultant necrotic symptom of the tissue is also induced by application of acetone extract of the fungus growing on potato sucrose agar (PSA) culture. The active principles to induce the necrosis are purified from the acetone extract as follows. After evaporation of hexane-benzene-EtOAc (1:2:1, v/v/v) the extract was fractioned on silica gel column, using a solvent gradient system from n-hexane to EtOAc and then to MeOH. The active fractions were purified with HPLC on Nucleosil 50-5 column by eluting n-hexane to EtOAc. Their structures are established by using spectroscopic techniques and synthesis to 4-hydroxymellein and mellein, respectively. Application of small amount of these compounds induce expansion of the necrotic symptom into the tissue and accumulated ipomeamarone. Conclusively, these compounds acted as phytotoxins (inducing necrosis) and as elicitors (eliciting the phytoalexin).

• Biotechnology and Bioprocess Engineering:BBE
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• v.9 no.5
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• pp.389-392
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• 2004

In order to produce a harmful protein more efficiently, this expression cassette, dubbed pCol-MICT, is directed by the colicin promoter, and was constructed by the insertion of a $rrnBT_1T_2$ fragment of pEXP7, and a MxelnteinCBD fragment of pTXB3, into pSH375. To test whether harmful proteins, including proteolytic enzymes, could be effectively produced by this cassette, the carboxypeptidase (CPase) Taq gene was inserted into the pCol-MICT cassette to yield pCol-CPase Taq-MICT. E coli W3l 10 tells harboring pCol-CPase Taq-MICT produced a large quantity of this enzyme, as much as 47.2 mg of purified from per liter of culture, when cultured in the presence of mitomycin C ($0.4{\mu}g/mL$). This indicates that the colicin promoter-controlled E, coli expression cassette was able to produce almost 8 times of protein than the conventional tar promoter-based system, and that this cassette may be useful in the Synthesis of other harmful proteins.

• Journal of the Korean Ceramic Society
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• v.54 no.1
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• pp.23-27
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• 2017

A series of $CeO_2-TiO_2$ composite samples with different Ce/Ti molar ratios were prepared by the paper template. Powder X-ray diffraction (XRD) and transmission electron microscopy (TEM) were used to confirm a face-centered cubic lattice of $CeO_2$ with Ce/Ti =8:2 or 9:1 and a two phase mixture of anatase titania and face-centered cubic ceria with Ce/Ti = 7 : 3. The field emission scanning electron microscopy (FESEM) results suggest that the products are micron braid structures consisting of fibers with diameters in a range of $1-6{\mu}m$ and lengths of several hundred micrometers. $N_2$ absorption-desorption testing shows that the composite at Ce/Ti molar fraction of 8 : 2 has the largest BET surface area (about $81m^2{\cdot}g^{-1}$). Compared to the pure $CeO_2$ sample, the composites show superior catalytic activity for $H_2$ reduction and CO oxidation. For the micron braid structure $CeO_2-TiO_2$ composite (Ce/Ti = 8 : 2), due to the high surface area and the solid solution with appropriate $Ti^{4+}$ incorporation, the CO conversion at about $280^{\circ}C$ was above 50% and at $400^{\circ}C$ was 100%.

• The Journal of Korean Academy of Prosthodontics
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• v.36 no.6
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• pp.816-831
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• 1998

Bony fixation of implants during the early phase of healing is important in order to get secondary stability of the implant assuring the success of the treatment. Because the successful placement of the implant is limited by the quality and quantity of bone, other agents which stimulate bone formation in the peri-implant spaces has been illustrated. Platelet-derived growth factor (PDGF) has been shown to regulate DNA and protein synthesis in bone cells in vitro and to interact synergistically to enhance soft tissue wound healing in vivo. The purpose of this study was to evaluate bone promotion around implants which were augmented with sagittal split osteotomy or autogenous veneer bone graft using the platelet derived growth factor(PDGF). After placement of newly designed twenty four screw-type implants, which were 12mm in length and 4mm in diameter in 6 dogs. $4{\mu}g$ of PDGF B/B was applied with surgicel carriers. The dogs were sacrificed at 3 days, 1, 2, 3, 6, and 12 weeks after implantation. Specimens were examined clinically, radiographically, histologically, and histomorphometrically. The results were as follows: 1. Clinically and radiologically, there was no significant difference in bone formation and healing pattern between experimental and control group. 2. In autogenous veneer bone graft group, bone formation was observed at 1st week in the experimental groups but 2nd week in the control groups. At 3rd week, the expeimental groups showed more bone formation comparing to the control groups. 3. In sagittal split osteotomy group, bone formation was observed at 1st week in both groups. But the experimental groups showed more bone formation comparing to the control groups after 2nd week. 4. The bone growth rate of experimental group was more rapid than that of control group. These results indicated that PDGF did not affect the initiation of new bone formation, but it accelerated the bone formation at the early period.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.16 no.4
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• pp.166-171
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• 2006

[ $Cu_2O$ ] and Cu have been synthesized from the layered organic-inorganic hybrid, $Cu_2(OH)_3(CH_3COO){\cdot}H_2O$, assisted by microwave irradiation. $Cu_2O$ is formed in aqueous glucose solution, while metallic Cu is formed in ethylene glycol by reduction of $Cu_2(OH)_3(CH_3COO){\cdot}H_2O$. The influence of microwave irradiation time and concentration of glucose on $Cu_2O$ particles formation and growth has been examined. The morphologies of $Cu_2O$ particles change from spheres with a few fm size to nanowires with diameter of 40 nm as increasing the microwave irradiation times.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2004.07b
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• pp.1062-1065
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• 2004

The importance of display is becoming increasingly important due to the development of information and industry where it leads to diverse and abundant information in today's society. The demand and application range for FPD(Flat Panel Display), specifically represented by LCD(Liquid Crystal Display) and PDP(Plasma Display Panel), have been rapidly growing for its outstanding performance and convenience amongst many other forms of display. The current focus has been on OLED(Organic Light Emitting Diode) in the mobile form, which has just entered into mass production amid the different types of FPD. Many studies are being conducted in regards to device, vacuum evaporation, encapsulation, and drive circuits with the development of device as a matter of the utmost concern. This study develops a new type of light-emitting materials by synthesizing medical polymer organic chitosan and phosphor material CuS. Chitosan itself satisfies the Pool-Frenkel Effect, an I-V specific curve, with a thin film under $20{mu}m$, and demonstrates production possibility for a living body sensors solely with the thin film. Furthermore, it enables production possibility for EML of organic EL device(Emitting Layer) with liquid Green light emitting and Blue light emitting as a result of synthesis with phosphor material.

• Preventive Nutrition and Food Science
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• v.20 no.1
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• pp.73-77
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• 2015

As an approach to search for chemopreventive agents, we tested p-coumaric acid, 3-methoxy-p-coumaric acid (ferulic acid), and 3,5-dimethoxy-p-coumaric acid (sinapic acid) in B16/F10 melanoma cells. Intracellular melanin contents were determined by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide assay and cytotoxicity of the compounds were examined by lactate dehydrogenase (LDH) release. p-Coumaric acid showed inhibitory effect on melanogenesis, but ferulic acid increased melanin content, and sinapic acid had almost no effect on melanogenesis. Treatment with ferulic acid resulted in a 2 to 3 fold elevation in the production of melanin. Correlatively, cell viability decreased in a dose-dependent manner when treated with ferulic acid. However, ferulic acid did not affect the LDH release from the cells. Treatment with sinapic acid resulted in a 50~60% elevation in the release of LDH when treated with a $200{\mu}g/mL$ concentration and showed neither cytostasis nor increase of melanin synthesis in a dose-dependent manner. Taken together, p-coumaric acid inhibits melanogenesis, ferulic acid induces melanogenesis, and sinapic acid exerts cytotoxic effects in B16/F10 murine melanoma cells. The results indicate that the addition of methoxy groups to p-coumaric acid shows the melanogenic or cytotoxic effects in melanoma cells compared to the original compound. Therefore, this study suggests the possibility that methoxylated p-coumaric acid, ferulic acid can be used as a chemopreventive agent.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.18
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• pp.7785-7792
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• 2014

Background: Valproic acid (VPA) is a potent anticancer and antiangiogenic agent. However, design and synthesis of chemical derivatives with improved antiangiogenic and anticancer activities are still necessary. In this study a library of novel derivatives of VPA was synthesized and tested. Methods: A human liver cancer cell line (HepG2) and a human normal embryonic kidney cell line (HEK 293) were exposed to various concentrations of VPA derivatives for 24 hours and cell viability was checked by MTT colorimetric assay. Anti-angiogenic properties were evaluated in transgenic zebrafish embryos. Results: N-valproylglycine derivatives suppressed survival almost 70% (p value 0.001) in HepG2 cells but only 10-12% in HEK 293 cells (p value 0.133). They also suppressed angiogenic blood vessel formation by 80% when used between $2-20{\mu}M$ in zebrafish embryos. Valproic acid hydrazides showed moderate level of anticancer activity by affecting 30-50% (p value 0.001) of cell viability in HepG2 cells and 8-10% in HEK293 cells (p value 0.034). Conclusion: The majority of compounds in this study showed potent and stronger antiangiogenic and anticancer activity than VPA. They proved selectively toxic to cancer cells and safer for normal cells. Moreover, these compounds inhibited developmental angiogenesis in zebrafish embryos. Based on the fact that liver is a highly vascularized organ, in case of liver carcinoma these compounds have the potential to target the pathological angiogenesis and could be an effective strategy to treat hepatocellular carcinoma.