• The Korean Journal of Physiology and Pharmacology
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• 제4권5호
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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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• 제30권1호
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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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• 제25권3호
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• pp.185-191
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• 2007

목적 : 가시오갈피 뿌리 추출물(Extract of Eleuthrococcus senticosus Maxim root, ESMR)의 면역세포의 활성에 미치는 효과와 마우스 종양세포에서 세포독성 및 방사선 병용효과를 알기위해서 본 연구를 시행하였다. 대상 및 방법: 가시오갈피 뿌리(250 g)를 80% 메탄올로 추출한 다음, 감압농축 및 동결과정을 통해 분획을 얻었다. 세포 주는 섬유육종세포를 이용하였으며, 방사선조사는 저 에너지(250 KV)용 방사선 기기를 사용 하였다. 가시오갈피 추출물의 면역세포에 미치는 활성효과를 알아보기 위해서 마우스 비장 및 흉선세포의 생존율 측정과 비장 및 흉선림프구 아집단을 측정하였다. 세포독성 정도를 알아보기 위하여 clonogenic assay법을 이용하였다. 방사선조사 단독군의 경우 2, 4 및 6 Gy를 마우스 섬유육종세포(FSa II)에 조사하였으며, 가시오갈피와 방사선 병용군의 경우 0.2 mg/ml 농도의 가시오갈피를 방사선조사 1시간 전에 마우스 섬유육종세포에 접촉시켰다. 결 과: 가시오갈피 /뿌리 추출물 각각 10 ${\mu}g/ml$과 $100{\mu}g/ml$을 첨가한 마우스 비장 및 흉선세포 생존율은 다음과 같았다. 마우스 비장세포는 각각 $8.8{\pm}1.7%$와 $37.7{\pm}2.1%$로 증가하였으며, 흉선세포에서는 100 ${\mu}g/ml$에서 $16.7{\pm}1.6%$로 증가하였다. ESMR을 경구 투여한 마우스 비장 및 흉선림프구는 다음과 같았다. 마우스 비장세포의 B cell은 41.5 $({\pm}1.3)$에서 46.0 $({\pm}1.5)%$로, T cell은 16.9 $({\pm}0.9)$에서 22.3 $({\pm}1.2)%$로 증가하였으며, 특히 Helper T (Th) cell은 10.4 10.4 $({\pm}0.7)$에서 14.2 $({\pm}0.8)%$로, Cytotoxic T (Tc) cell은 3.6 $({\pm}0.4)$에서 5.6 $({\pm}0.3)%$로 증가하였다. 그러나 마우스 흉선세포에서 T림프구의 증가율은 거의 보이지 않았다. 마우스 섬유육종 세포에서 ESMR의 세포독성을 나타내는 생존분율은 0.2, 2.0 mg/m에서 각각 $0.36{\pm}0.02$, $0.05{\pm}0.02$으로 나타났다. 마우스 섬유육종 세포를 접종한 마우스에 ESMR 0.2 mg/ml 농도를 1시간 동안 접촉시킨 다음, 방사선조사량 2, 4 및 6 Gy를 조사한 후 얻은 생존분물은 0.39, 0.22 및 0.06이었으며, 방사선조사 단독군의 경우는 0.76, 0.47 및 0.37로 나타났다. 그리고 두 군간의 차이는 통계학적 의미를 나타냈다(p<0.05). 결 론: 가시오갈피 뿌리 추출물은 in vitro 실험에서 마우스 비장세포의 생존율을 증가시켰다. In vivo 실험에서는 마우스 비장 내 B세포 및 T세포를 증가시켰으나, 마우스 흉선세포에 대해서는 증가를 보이지 않았다. ESMR은 마우스 섬유육종 세포에 대해 강한 세포독성 효과를 나타냈다. FSa II를 접종한 마우스에서 방사선 단독 보다 ESMR을 병용한 경우 방사선에 의한 세포손상이 약 50% 이상 증가되었으며, 두 군간의 차이는 통계학적 의미를 나타냈다(p<0.05).

• Restorative Dentistry and Endodontics
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• 제27권3호
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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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• 제18권1호
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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.

• 한국초전도ㆍ저온공학회논문지
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• 제6권2호
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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.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2011년도 제40회 동계학술대회 초록집
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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.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 1999년도 춘계학술대회 논문집
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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.

• 대한전기학회논문지
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• 제41권7호
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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.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2003년도 하계학술대회 논문집 C
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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.