• 한국구조물진단유지관리공학회 논문집
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• 제20권5호
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• pp.75-84
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• 2016

본 연구에서는 해수 침지 온도에 따른 비소성 시멘트 경화체의 물리적 및 역학적 특성에 대해 비교 분석하였다. 비소성 시멘트는 플라이애시와 고로슬래그미분말을 6:4, 7:3 및 8:2의 중량비로 혼합하여 수산화나트륨과 액상규산나트륨으로 알칼리 활성화 하여 제작되었다. 알칼리 활성화를 위한 활성화제는 플라이애시와 고로슬래그미분말을 혼합한 중량의 5%로 하였으며, 화학첨가제로 탄산칼슘이 사용되었다. 본 연구에서는 알칼리 활성화된 시험체들을 3가지 다른 온도($5^{\circ}C$, $15^{\circ}C$ 및 $25^{\circ}C$)의 해수에 각각 침지 시킨 후, 침지 재령 3일 및 28일에 대해 경화체의 압축 강도, 밀도 및 흡수율을 측정하였으며, 해수 침지 재령 28일에 대해서는 XRD 및 SEM 시험 분석을 실시하였다. 또한, 해수 침지 재령 28일에 대하여 시험체들 내의 수용성 염화물(자유염화물) 및 산-가용성 염화물(총염화물) 함유량을 측정하여 분석하였다. 본 연구에서 해수온도별로 침지시킨 플라이애시-고로슬래그미분말 혼합 알칼리 활성화 경화체는 플라이애시 혼합률이 증가함에 따라 밀도 감소, 흡수율 증가 및 강도가 감소하는 경향을 나타냈다. 또한 플라이애시 혼합률이 증가할수록 시험체 내의 수용성 염화물 및 산-가용성 염화물의 양이 증가하는 것으로 나타났다. 본 연구에서 제작된 플라이애시-고로슬래그미분말 혼합 알칼리 활성화 경화체는 노출된 해수 온도 영향으로 인한 강도 차이는 없는 것으로 판단되며, 플라이애시와 고로슬래그미분말의 혼합중량비에 따라 강도 특성이 달라지는 것으로 나타났다.

• 전기화학회지
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• 제9권2호
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• pp.70-76
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• 2006

마이크로 전기화학 실험법인 비접촉식 미세방울셀이 산 용액에 노출된 저 크롬이 함유된 스테인리스강(STS 316)과 같이 젖음성이 높은 전기화학계에 사용되는데 어려움이 있었다. 음압의 인가, 방울의 크기 제어 그리고 소수성의 개스킷의 사용은 높은 젖음성을 지닌 표면에서 비접촉식 미세방울셀의 적용을 가능하게 하였다. 개선된 미세방울셀의 신뢰성을 확인하고자 3종류의 다른 계-산성염화용액과 고 크롬 페라이트 스테인리스강, 산성염화용액과 STS 316 그리고 중성염화용액과 STS 316-에 대하여 개선된 미세방울셀로 국부부식 연구를 수행하였다. 첫째 산성용액에서 고 크롬강의 양극 분극 결과는 $\alpha/\sigma$ 계면 근처에서 국부부식이 크롬 고갈층에 의한 것임을 보여주었다. 둘째 산성용액에서 STS316의 양극 분극실험이 개선된 미세방울셀에서 성공적으로 수행됨을 확인할 수 있었다. 특히, 미세방울셀에서 얻어진 국부 양극 분극곡선을 통해 STS316의 내식성에 미치는 $\delta$-라이트 영향을 밝힐 수 있었다. 마지막으로 중성염화 용액에서 STS316의 양극 분극곡선은 핏팅 저항성이 $\delta$-페라이트보다 개재물에 의존됨을 보여주었다.

• 동의생리병리학회지
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• 제29권2호
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• pp.180-188
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• 2015

This study was conducted to investigate the relaxation effects and its mechanisms of Nelumbinis Semen(NS) extract in isolated rabbit corpus cavernous tissues. In order to examine the relaxation effects and its mechanisms of NS, we treated the ethanol extract of NS(0.01-3.0 mg/ml) and indomethacin(IM), tetraethylammonium chloride(TEA), Nω -nitro-L-arginine (L-NNA), methylene blue(MB) were treated before NS extract to contracted strips induced by PE 1 μM. We also treated calcium chloride(Ca) 1 mM after pretreatment of NS extract in Ca²⁺-free krebs-ringer solution to contracted strips induced by PE. Cell viability and NO concentration on human umbilical vein endothelial cell(HUVEC) was measured by MTT assay, Griess reagent system. eNOS production was investigated by histochemical and immunohistochemical staining. NS extract was significantly affected on the relaxation of cavernous strips and NS extract-induced relaxation was not different by pretreatment of IM, TEA, MB, but inhibited by the pretreatment of L-NNA. And increase of contraction induced by Ca²⁺ addition, in a Ca²⁺-free solution, was decreased by pretreatment of NS. NO concentration on HUVEC was increased. When NS extract was applicated on corpus cavernosum of penis(CCP) in SHR, ratio of smooth muscles to collage fibers by PE was decreased and formation of eNOS around helicine artery was increased. These results suggest that CCP relaxation effects of NS extract are shown by suppressing influx of extracellular Ca²⁺ through the production of NO and eNOS.

• 대한한방내과학회지
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• 제18권1호
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• pp.1-14
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• 1997

An experimental study was done to investigate the spontaneous movements to the isolated ileum with liquid extracts of Samchulgunbitang. Then the action of gastric ulcer, gastric-juice secretion, the free acidity, total acidity, pepsin output, the transport ability in the intestine, analgesic effect and sleeping time were measured. The following results were obtained; 1. As to the spontaneous movements in the isolated ileum, the effect of contraction against suppression was recognized. 2. The effects of contraction against suppression induced by acetylcholine chloride and barium chloride were recognized on the gastric funds strip significantly. 3. The preventive effect of Samchulgunbitang on the pylorus-lightedulcer in rat was recognized significantly. 4. The anti-ulcer effect of Samchulgunbitang was not recognized on the gastric ulcer caused by indomethacin. 5. The effects of decreasing on the secretion gastric juice, the free acidity, total acidity and pepsin output of Samchulgunbitang were recognized significantly. 6. The transport rate in the small intestine of Samchulgunbitang was decreased. 7. The transport rate in the large intestine of Samchulgunbitang was increased. 8. The analgesic effect of Samchulgunbitang caused by acetic acid was recognized significantly. 9. The sleeping time caused by pentobarbital-Na of Samchulgunbitang was prolonged significantly. According to the results, it is considered that the Samchulgunbitang has effects of gastric ulcer, chronic gastritis, hyper-acidity, gastroptosis such as abdominal discomfort, gastric acid, indigestion and anorexia.

• 대한한의학회지
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• 제24권1호
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• pp.141-154
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• 2003

Objectives : This study was undertaken to define the effect of Diospyros kaki L. Radix or Diospyros kaki L. Folium on phenylephrine-induced arterial contraction and the mechanism of Diospyros kaki L. Radix or Diospyros kaki L. Foliuminduced relaxation. Methods : In order to investigate the effect of Diospyros kaki L. Radix or Diospyros kaki L. Folium on contracted rabbit carotid arterial strips, transverse strips with intact or damaged endothelium were used for the experiment using organ bath. Diospyros kaki L. Radix or Diospyros kaki L. Folium extract was infused into contracted arterial strips induced by phenylephrine. To analyze the mechanism of Diospyros kaki L. Radix or Diospyros kaki L. Folium-induced relaxation, Diospyros kaki L. Radix or Diospyros kaki L. Folium extract was infused into contracted arterial strips induced by phenylephrine after treatment with indomethacin, $N{\omega}-nitro-L-arginine$, methylene blue or tetraethylammonium chloride, and $Ca^{2+}$ was infused into contracted arterial strips induced by phenylephrine after treatment of Diospyros kaki L. Radix or Diospyros kaki L. Folium in a $Ca^{2+}$-free solution. Results : Diospyros kaki L. Radix or Diospyros kaki L. Folium showed relaxation effect on arterial strip with endothelium contracted by phenylephrine, but in the strips without endothelium, Diospyros kaki L. Radix or Diospyros kaki L. Folium-induced relaxation was significantly inhibited. The endothelium-dependent relaxation induced by Diospyros kaki L. Radix or Diospyros kaki L. Folium was decreased by pretreatment with $N{\omega}-nitro-L-arginine$ or methylene blue but it was not observed in the strips pretreated with indomethacin or tetraethylammonium chloride. When $Ca^{2+}$ was applied to the strips which were contracted by phenylephrine in a $Ca^{2+}$-free solution, arterial contraction was increased. However, pretreatment with Diospyros kaki L. Radix or Diospyros kaki L. Folium inhibited contractile response to $Ca^{2+}$. Conclusions : Diospyros kaki L. Radix or Diospyros kaki L. Folium may suppress influx of extra- cellular $Ca^{2+}$ through the formation of nitric oxide in the vascular endothelial cells.

• 동의생리병리학회지
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• 제27권6호
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• pp.730-737
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• 2013

The purpose of this study is to investigate vasorelaxant effect of Epimedium koreanum(EK) extract on rabbit carotid artery. In this study, to determine vasorelaxant effect of EK extract on rabbit carotid artery, arterial rings with intact or damaged endothelium were used for experiment using organ bath, and were contracted by norepinephrine(NE). After being contracted, arterial rings were treated with EK extract in a dose-dependent manner To study its mechanism, the contracted arterial rings induced by NE were pretreated with indomethacin(IM), $N_{\omega}$-nitro-L-arginine(L-NNA), methylene blue(MB) or tetraethylammonium chloride(TEA) and 0.1 $mg/m{\ell}$ EK extract was added. To analyze the effect of the EK extract on influx of extracellular calcium chloride($Ca^{2+}$) in rabbit carotid artery, in $Ca^{2+}$-free krebs solution, krebs solution containing 1 mM $Ca^{2+}$ was infused into the contracted arterial ring by NE after pretreatment of EK extract. To measure the cytotoxicity of the EK extract, cell viability of human umbilical vein endothelial cell(HUVEC) was measured by MTT assay, and nitric oxide(NO) was measured by Griess reagent. The EK extract significantly was relaxed the arterial ring with intact endothelium contracted by NE, but the vasorelaxant effect of the EK extract was inhibited in the arterial rings with damaged endothelium. The vasorelaxant effect of the EK extract was not different between the IM-pretreatedand and non-treated arterial rings. The vasorelaxant effect of EK extract were significantly inhibited, when arterial rings were pretreated with L-NNA, TEA, MB. And in $Ca^{2+}$-free krebs solution, increasing of arterial contraction by $Ca^{2+}$ addition were also inhibited by the treatment of EK, but not significant. The treatment of EK extract was increased NO concentration in HUVEC. This study suggested that the vasorelaxant effect of EK extract would be related with EDHF and NO production and increasing of cyclic GMP.

• 한국미생물·생명공학회지
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• 제20권4호
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• pp.459-469
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• 1992

세균을 고정화시켜 에탄올을 생산하기 위하여 4종류의 Zymomonas mobilis를 사용하였다. 이들 중 glucose와 sucrose로부터의 에탄올생성능이 가장 우수한 것으로 Zymomonas mobilis KCTC 1534를 선별하였다. 선별된 균주의 고정화 특성을 살펴본 결과 발효 최적온도와 pH는 각각 $33^{\circ}C$와 5.0으로 고정화 균체나 유리 균체에 대하여 큰 차이가 없었다. 그러나 최대 발효 가능온도는 유리 균체가 $37^{\circ}C$인데 비하여 alginate, k-carageenan, agar에 고정화했을 때 각각 43, 37, $40^{\circ}C$로서 균체를 고정화할 경우 유리균체에서 보다 높은 온도에서도 발효가 가능함을 확인하였다. Alginate 고정화 균체는 2% alginate 농도에 건조균체량 11.74g/$\ell$가 최적이었따. 고정화 균체의 활성화는 10% glucose 농도의 생산배지에서 20~25시간을 요 하였고 $4^{\circ}C$에 보관할 경우 calcium chloride 2%를 가한 증균배지에서 약 4주간은 전균체량의 90% 이상이, 10주간에는 80% 이상의 균체가 생존하였다.

• 한국농촌생활과학회지
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• 제10권2호
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• pp.60-70
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• 1999

Changes in the nutritional components of Toha-jeot, salt-fermented Toha shrimp (Caridina denticulata denticulata $D_EH_{AAN}$), which was salted with a low-salt group of 15% sodium chloride (L), a high-salt group of 23% sodium chloride (H), a 50% conventional soybean sauce group (S) during long fermentation were investigated. These three groups were refrigerated at ${4\pm}1^{\circ}C$ and then taken out for analysis at three month intervals during 9 month. Even in the process of a long fermentation, the moisture containment of Toha-jeot in group L and S is 76.0~73.6% and in group H it is 70.0%, which are similar in all three groups. In case of the salinity, there was no change in groups L, H but it was lowered in group S during the fermentation. In all groups there was no change of pH. The free amino acid contents in Toha-jeot, of which ornitine, glutamic acid, leucine, alanine, lysine and valine occupy the majority, in order of abundance, increased gradually up to six months of fermentation and decreased by nine months. But free amino acid contents of S group increased continuously during the fermentation process. Hypoxanthine was altered almost among other nucleotides. ATP was not detected, IMP and inosine had disappeared after the six months for mentation. ADP was not detected after the nine months fermentation. Monoene, polyene and n-3 fatty acids were increased and saturated fatty acids were decreased in L and H groups. However, no changes of fatty acid contents in S group during fermentation were showed. The fatty acid contents of three groups, of which $C_{18:1},\;C_{16:0},\;C_{16:1}$ and $C_{20:5}$ occupy the majority, Mineral content of Toha-jeot is mainly consisted of Na, Ca, K and Mg. In the Hunter values, the redness of L group was superior to that of other groups.

• Korean Chemical Engineering Research
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• 제50권2호
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• pp.211-216
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• 2012

염화제이철 수용액에 의한 스테인레스 강판의 식각반응에 관한 연구를 수행하였다. 식각액 교반속도, 식각온도, $Fe^{3+}$ 이온 농도, 식각액의 유리산도 및 비중 등 여러 공정변수가 식각속도에 미치는 영향에 대해 조사하였고, 그 결과, AK(aluminum-killed) 철, 크롬(chlomium) 강, 그리고 스테인레스 강(STS430J1L 합금)의 식각반응이 1차 반응식을 잘 따름을 알 수 있었다. 또한 식각액의 피로도(fatigue ratio)가 16% 이하로 유지되면 식각액 내에 슬러지가 발생하지 않으며, 식각된 강판의 표면거칠기 또한 좋아짐을 알 수 있었다. 본 연구에서 조사한 범위 내에서는, 식각액의 보메(Baume)가 증가하면 식각속도는 감소하나 유리산도가 식각속도에 미치는 영향은 미비함을 알 수 있었다. 한편 본 연구의 실험결과는 공정모델링을 통해 유도된 식각속도식의 계산결과와 잘 일치함을 알 수 있었다.

• The Korean Journal of Physiology and Pharmacology
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• 제5권3호
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• pp.231-241
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• 2001

The mammalian cortical collecting duct (CCD) plays a major role in regulating renal NaCl reabsorption, which is important in $Na^+$ and $Cl^-$ homeostasis. The M-1 cell line, derived from the mouse cortical collecting duct, has been used as a mammalian model of the study on the electrolytes transport in CCD. M-1 cells were grown on collagen-coated permeable support and short circuit current $(I_{sc})$ was measured. M-1 cells developed amiloride-sensitive current $5{\sim}7$ days after seeding. Apical and basolateral addition of ATP induced increase in $I_{sc}$ in M-1 cells, which was partly retained in $Na^+-free$ or $Cl^--free$ solution, indicating that ATP increased $Na^+$ absorption and $Cl^-$ secretion in M-1 cells. $Cl^-$ secretion was mediated by the activation of apical cystic fibrosis transmembrane regulator (CFTR) chloride channels and $Ca^{2+}-activated$ chloride channels, but $Na^+$ absorption was not mediated by activation of epithelal sodium channel (ENaC). ATP increased cAMP content in M-1 cells. The RT-PCR analysis demonstrated that M-1 cells express $P2Y_2,\;P2X_3\;and\;P2Y_4$ receptors. These results showed that ATP regulates $Na^+$ and $Cl^-$ transports via multiple P2 purinoceptors on the apical and basolateral membranes in M-1 cells.