• The Korean Journal of Physiology and Pharmacology
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• v.4 no.5
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• pp.385-391
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• 2000

Using the patch-clamp technique, we investigated the alteration of 4-aminopyridine(4-AP)-sensitive, voltage-dependent $K^+$ channel (Kv) in the mesenteric arterial smooth muscle cell (MASMC) of renovascular hypertensive model, one-kidney one-clip Goldblatt hypertensive rat (GBH). To isolate $K_V$ current, internal pipette solution contained 5 mM ATP and 10 mM EGTA. Under these condition, MASMC was depolarized by 4-AP, but charybdotoxin did not affect membrane potential. Membrane potential of hypertensive cell $(-40.3{\pm}3.2\;mV)$ was reduced when compared to that of normotensive cell $(-59.5{\pm}2.8\;mV).$ Outward $K^+$ current of hypertensive cell was significantly reduced when compared to normotensive cell. At 60 mV, the outward currents were $19.10{\pm}1.91$ and $14.06{\pm}1.05$ pA/pF in normotensive cell and hypertensive cell respectively. 4-AP-sensitive $K^+$ current was also smaller in hypertensive cell $(4.28{\pm}0.38\;pA/pF)$ than in normotensive cell $(7.65{\pm}0.52\;pA/pF).$ The values of half activation voltage $(V_{1/2})$ and slope factor (k1) as well as the values of half inactivation voltage $(V_{1/2})$ and slope factor (k1) were virtually similar between GBH and NTR. These results suggest that the decrease of 4-AP-sensitive $K^+$ current contributes to a depolarization of membrane potential, which leads to development of vascular tone in GBH.

• Journal of Periodontal and Implant Science
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• v.30 no.1
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• pp.121-134
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• 2000

Root conditioning has introduced to dissolve the smear layer and to produce surface demineralization, resulting to exposure of dentin collagen fibril and opening of dentinal tubules. The purpose of the present study was to examine the effect of different concentration and application time of tetracycline-HCL on root conditioning. Total 40 root specimen were prepared from 20 periodontitis-prone human single rooted tooth. The specimen were treated with tetracycline-HCL solution(20mg/ml, 50mg/ml, 100mg/ml)for 20 sec, 3 min, 5 min., and saline for 30 sec. The application method was rubbing method with cotton pellet. Under the scanning electron microscopy(20KV), the extent of smear removal and opening of the dentinal tubules were examined at x 3000. The following results were obtained. 1. Treatment of root specimen with saline did not remove the smear layer and open the dentinal tubules. 2. Treatment of root specimen with different concentration of tetracycline-HCL for 20 sec also did not remove the smear layer completely. 3. Treatment of root specimen with different concentration of tetracycline-HCL for 3 min opened the dentinal tubules and removed smear layer. 4. Treatment of root specimen with 50mg/ml of tetracycline-HCL for 3 min showed collagen fibril within the opened dentinal tubules. In conclusion, the effect of root conditioning with tetracycline-HCL is more dependent on the application time than the application concentration. Root conditioning with 50mg/ml tetracycline-HCL for 3 min is enough for obtaining the periodontal regeneration.

• Radiation Oncology Journal
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• v.25 no.3
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• pp.185-191
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• 2007

Purpose: This study was performed to investigate the effects of immune cell activation and the antitumor effect for the combination of treatment with X-irradiation and E/eutherococcus senticosus Maxim Root (ESMR) on mouse tumor cells. Materials and Methods: ESMR (250g) was extracted with 80% methanol, concentrated under decompression and lyophilized. To determine whether ESMR is able to activate the immune cells or not, the proliferation of splenocytes in vitro and the number of B cells and T cells in splenic lymphocytes in ESMR-pretreated mice were evaluated. X-irradiation was given to the mouse fibrosarcoma tumor cells (FSa II) by 250 kv X-irradiation machine. The cytotoxicity of ESMR was evaluated from its ability to reduce the clonogenecity of FSa II cells. In X-irradiation alone group, each 2, 4, 6 and 8 Gy was given to FSa II cells. In X-irradiation with ESMR group, 0.2 mg/ml of ESMR was exposed to FSa II cells for 1 hour before X-irradiation. Results: The proliferation of cultured mouse splenocytes and thymocytes were enhanced by the addition of ESMR in vitro. The number of B cells and T cells in mouse splenic lymphocytes was significantly increased in ESMR pretreated mice in vivo. In FSa II cells that received a combination of 0.2 mg/ml of ESMR with X-irradiation exposure, the survival fraction with a dose of 2, 4 and 6 Gy was $0.39{\pm}0.005$, $0.22{\pm}0.005$ and $0.06{\pm}0.007$, respectively. For FSa II cells treated with X-irradiation alone, the survival fraction with a dose of 2, 4 and 6 Gy was $0.76{\pm}0.02$, $0.47{\pm}0.008$ and $0.37{\pm}0.01$. The difference in the survival fraction of the mouse FSa II cells treated with and without ESMR was statistically significant (p<0.05). Conclusion: Treatment with ESMR increased cell viability of mouse splenocytes in vitro and especially the subpopulation of B cells and T cells in splenocytes in ESMR-pretreated mice. However, treatment with ESMR did not increase the level of Th and Tc subpopulations in the thymocytes. Treatment with the combination of ESMR and X-irradiation was more cytotoxic to mouse tumor cells than treatment with X-irradiation alone; this finding was statistically significant.

• Restorative Dentistry and Endodontics
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• v.27 no.3
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• pp.215-231
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• 2002

삼차신경절의 뉴론이 구강악안면영역에서의 촉각, 압각, 온도각 및 통각 등 다양한 감각을 중추신경계로 전달하는 역할을 하는 것은 주지의 사실이다. 이러한 신경전달에 있어서 이온통로는 감각정보를 전달하는데 핵심적인 역할을 수행한다. 이 중 소디움 통로는 활동전위의 발생에 중요하며, 칼슘 통로는 시냅스 전도에 있어서 필수적인 역할을 수행하고, 포타슘 통로는 안정막전압의 유지 및 재분극에 관여한다. 최근에 여러 가지의 이온통로들의 뇌조직내의 분포에 관한 연구가 시작되고 있는데 삼차신경의 일차구심뉴론이 종지하는 삼차신경핵 즉 삼차신경 척수감각핵, 삼차신경 주감각핵, 삼차신경 중뇌핵 및 삼차신경 운동핵에 존재하는 이온통로에 관한 연구는 매우 희소하여 본 연구에서는 횐쥐의 삼차신경 핵에 존재하는 소디움, 칼슘 및 포타슘 이온통로들을 면역조직화학적 방법으로 조사하여 다음과 같은 결과를 얻었다. (1) 소디움 통로는 삼차신경 척수감각핵, 삼차신경 주감각핵 및 삼차신경 운동핵 모두에서 강하게 염색되었다. (2) 칼슘 통로는 삼차신경 척수감각핵에서는 N-type 통로가 중등도로 염색되었으며 , P/Q-type 통로는 약하게 염색되었으나 R-type 통로는 거의 염색되지 않았다. 삼차신경 주감각핵에서는 P/Q-type 통로가 매우 약하게 염색되었다. (3) 포타슘 통로는 삼차신경 척수감각핵과 삼차신경 주감각핵에서 inwardly rectifying 포타슘 통로(Kir 2.1)가 중등도로 염색되었고, voltage-gated 포타슘 통로(Kv 4.2)가 약하게 염색되었으며, BKCa는 그 염색 정도가 매우 약하게 나타났다. 이상의 결과를 종합해 볼 때 삼차신경 감각핵에는 소디움 통로의 분포가 가장 많았으며, 칼슘통로에서는 N-type이, 포타슘 통로 중에는 inwardly rectifying 통로(Kir 2.1)가 가장 많이 분포함을 관찰할 수 있었다.

• Restorative Dentistry and Endodontics
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• v.18 no.1
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• pp.173-186
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• 1993

The purpose of this study is to observe the morphological changes of prepared dentin surfaces by 5 dentin conditioning agents. Freshly extracted 48 healthy human molars were used in this study. The teeth were stored at $4^{\circ}C$ physiologic saline solution befor experiment. The teeth were cross-sectioned to expose dentin below 3.0mm at the cusp tip and above 2.0mm at the cemento-enamel junction with Crystal Cutter (MC411 D, Maruto Co., Japan). The specimens were then divided into 12 groups. The sectioned dentin surfaces in group 1, 3, 5, 7, 9, and 11 were prepared with No. 301 diamond point under air-water spray and those in group 2, 4, 6, 8, 10, and 12 were prepared with No. 700 carbide bur. The prepared dentin surfaces were conditioned with Nitric acid, Citric acid, Poly acrylic acid, EDTA, and Phosphoric acid. All the specimens were gold-coated with Eiko ion coater (Eiko-engineering Co.) and observed in Hitachi S-2300 Scanning electron microscope at 20 KV. The following results from this study were obtained; 1. The dentinal smear layers prepared with diamond point were compacted than those prepared with the carbide bur. 2. The dentinal smear layers prepared with diamond point or carbide bur were thick but after treatment of dentin conditioning agents smear layers were removed almost. 3. Irrespective of the uses of the diamond point or the carbide bur the morphological changes of dentin surfaces treated with the same conditioning agents were similar. 4. Treatment of nitric acid and EDTA was a little effect in removing dentinal smear layer. 5. Treatment of citric acid and phosphoric acid removed the smear layer very effectively and showed dissolution of peritubular dentin and opening of dentinal tubules.

• Progress in Superconductivity and Cryogenics
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• v.6 no.2
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• pp.25-28
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• 2004

Three-phase inductive superconducting fault current limiter (SFCL) with DC reactor rated on 6.6 $KV_{rms}/200 A_{rms}$ has been developed in Korea. This system consists of one DC reactor, AC/DC power converter, and a three-phase transformer, which is called magnetic core reactor (MCR). This paper deals with the short-circuit analysis of the SFCL. The DC reactor was the HTS solenoid coil whose inductance was 84mH. The power converter was performed as the dual-mode operation for dividing voltage between the rectifying devices. The short-term normal operation (1 see) and short-circuit tests (2∼3 cycles) of this SFCL were performed successfully. In regular short-circuit test, the fault current was limited as 30% of rated short-circuit current at 2 cycles after the fault. The experimental results have a very similar tendency to the simulation results. Using the technique for the fault detection and SCR firing control, the fault current limiting rate of the SFCL was improved. From this research, the parameters for design and manufacture of large-scale SFCL were obtained.

• Proceedings of the Korean Vacuum Society Conference
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• 2011.02a
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• pp.194-194
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• 2011

The effects of argon neutral beam (NB) energy on the amorphous carbon (a-C) films were investigated, while the a-C films were deposited by neutral particle beam assisted sputtering (NBAS) system. The energy of neutral particle beam can be controlled by reflector bias voltage directly as a unique operating parameter in this system. The deposition characteristics of the films investigated of Raman spectra, UV-visible spectroscopy, electrical conductivity, stress measurement system, and ellipsometer indicate the properties of amorphous carbon films can be manipulated by only NB energy (or reflector bias voltage) without changing any other process parameters. We report the effect of reflector bias voltage in the range from 0 to -1KV. By the increase of the reflector bias voltage, the amount of cross-linked sp2 clusters as well as the sp3 bonding in the a-C film coated by the NBAS system can be increased effectively and the composition of carbon thin films can be changed from nano-crystalline graphite phase to amorphous carbon phase.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1999.05a
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• pp.341-344
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• 1999

The effects of post annealing treatments of ferroelectrlclty in PZT(P $b_{1.05}$(Z $r_{0.52}$, $Ti_{0.48}$) $O_3$ thin film deposited on Pt/ $SiO_2$/Si substrate by RF-Magnetron sputtering methode was Investigated. Analyses by RTA(Rapid Thermal Annealing) treatments reveled that the crystallization process strongly depend on the healing temperature. The Perovskite structure with strong PZT (101) plan was obtained by RTA treatments at 75$0^{\circ}C$ With increasing RTA temperature of PZI thin films, the coercive field and remanent Polarization decreased, while saturation polarization( $P_{r}$) was decreased. P-E curves of Pt/PZT/Pt capacitor structures demonstrate typical hysteresiss loops. The measure values of $P_{r}$,. $E_{c}$ and dielectric constants by post annealed at 75$0^{\circ}C$ were 38 $\mu$C/$\textrm{cm}^2$ 35KV/cm and 974, respectively. Switching polarization versus fatigue characteristic showed 12% degradation up to 10$^{7}$ cycles.s.s.s.s.s.s.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.41 no.7
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• pp.703-711
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• 1992

As the underground area of the metropolitan becomes denser recently, an introduction of forced cooling system is under study to maximize the carrying capacity of existing cables in tunnels. Indirect water cooling system laid within trough will probably be adopted for the next 345KV class underground power cables in this country. The system covers a distance of 1.5-3.0Km for one water cooling interval and one water cooling interval is composed of several sub-sections that have different thermal analysis conditions. Thus the distribution of temperature in each sub-section is described by different conditions in general. In this paper a method that can accurately match the temperature of the coolant in the boundary between sub-sections has been suggested. An algorithm to find the temperature distributions effectively in the thermal system has also been presented. A computer program using this method has been tested in a smaple system and the results have shown the usefulness of this program.

• Proceedings of the KIEE Conference
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• 2003.07c
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• pp.1612-1614
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• 2003

80pF capacitive couplers were connected to six 6.6kV motor model coil terminals. The voltage applied to the coils were 3.81kv, 4.76 kV and 6.6kV, respectively. These stator coils have various types of artificial insulation defects such as large voids, semi-conductive coating damage and strand insulation fault. Digital PD detector(PDD) and turbine generator analyzer(TGA) were used to measure PD activity. TGA summarizes each plot with two quantities such as the normalized quantity number(NQN) and the peak PD magnitude(Qm). The PD levels in PD were measured with a conventional digital PD detector. Most of the defect mechanism of large motor stator winding can be associated with PD patterns such as internal and slot discharges. PD patterns coincide with PDD and TGA. These instruments have an input bandwidth of 40-400kHz and 0.1-350MHz. Surge testing detects faults in inter-turn winding of high voltage motor model coils.