냉각 Cycle Matching을 위한 핀-관 열교환기의 설계 Program 개발

김재열,마상동,최충현 조선대학교 에너지.자원신기술연구소 1997 에너지·자원신기술연구소 논문지 Vol.19 No.2

The purpose of this study is to develop the optimum design program of air cooled fin-tube heat exchanger. Logarithmic mean temperature difference(LMTD) method which is generally acceptable is used to design the air cooled fin-tube heat exchanger. In the coventional heat exchanger design by LMTD method, heat transfer, overall heat exchanger coefficient, and heat exchanger area are calculated by using the inlet and outlet temperature of heat exchanger. The design for the two phase flow in the tube of heat exchanger can be applied to the design of considers by LMTD method. A performance comparison according to the different refrigerants is provided using R-134a and R-12. As the result of this study, total heat transfer rate of heat exchanger using R-134a were found higher than that of using R-12 for the same operating conditions.

중추에서 Prostaglandin계가 Renin-angiotensin System에 미치는 영향

최영태,김종승,문성호,오형균,김재훈,전제열,염철호,윤평진 朝鮮大學校 附設 醫學硏究所 1997 The Medical Journal of Chosun University Vol.22 No.1

Role of prostaglandins on the renin-angiotensin system in the central nervous system was examined in normotensive and 2-kidney, 1 clip (2K1C) hypertensive rats. The experiment was done under thiopental (50 ㎎/㎏, IP) anesthesia. Captopril and indomethacin were injected into the right lateral cerebral ventricle. Arterial blood pressure and heart rate were recorded from the femoral artery. Intracerebroventricular (ICV) captopril (1 ㎎) caused a decrease in mean arterial pressure in both normotensive and 2K1C hypertensive rats. The depressor response to captopril was more sensitive in hyper-tensive rats than in normotensive rats. Indomethacin treatment (ICV, 200 ㎎) altered the depressor response to captopril neither in normotensive nor in hypertensive rats. These results suggest that the cardiovascular effect of renin-angiotensin system in the central nervous system may not be mediated via prostaglandin systems in normotensive and 2KlC hypertensive rats.

기니이픽 장관의 c-Kit 및 NK 1R 면역반응 세포구조에 대한 공초점 주사현미경적 연구

장인엽,김종중,문정석,김현곤,박찬국,전제열,전규배,조철희,유호진 조선대학교 2001 The Medical Journal of Chosun University Vol.26 No.1

Background and Objectives: Immunolabelling of interstitial Cajal(IC) cells in the intestinal wall has recently been developed by using a specific marker, the anti-c-Kit antibody. Substance-P is a well-known neurotransmitter in the gastro-intestinal tract. Since the gastro-intestinal wall structures have already been well documented in the guinea pig, immunohistochemistry was done for the c-Kit-positive IC network and substance-P receptor(NK1R) in an attempt to provide a morphological basis for the mechanism regulating gastro-intestinal movement. Materials and Methods: Cryosection and whole-mount preparations of guinea pig small intestine and colon were single and double immunolabelled using the anti-c-Kit and NK1R antibodies. Immunolabelled specimens were observed under a confocal laser scanning microscope. Results : According to a three dimensional reconstruction study, it was found that (1) the c-Kit-positive celluar networks were widely distributed in the intestinal wall, (2) c-Kit-positive celluar networks encircled the ganlion, with strands in reticular configurations, and (3) the c-Kit-positive cells showed colocalization with NK1R in circular muscle(CM), not myenteric plexus(MY). Conclusion: The charateristic profiles of IC containing c-Kit-positive celluar networks and the relationship between c-Kit-positive and NK1R-positive structures provide a morphological basis upon the mechanism regulating gastro-intestinal motility.

신성고혈압쥐에서 혈관내피층이 Phorbol Ester에 의한 수축에 미치는 영향

정수아,김형,차경훈,전제열,윤평진,염철호,박진,조남수,홍순표 대한순환기학회 2003 Korean Circulation Journal Vol.33 No.11

생쥐 소장의 interstitial cells of Cajal에서 ATP-민감성 K^(+)통로를 통한 향도잡이 전류의 조절

박찬국,김만우,김형석,최석,전제열 朝鮮大學校 附設 醫學硏究所 2005 The Medical Journal of Chosun University Vol.30 No.1

Objectives: This study was performed to investigate whether ATP-sensitive K^(+) channels exist in interstitial cells of Cajal (ICC) of mouse small intestine and the physiological role of ATP-sensitive K^(+) channels in gastrointestinal motility. Methods: ICC were isolated from mouse small intestine and cultured for 2 days. Electrical activities of ICC were recorded using the whole-cell patch-clamp technique at 30°C. Results: ICC displayed rhythmic slow waves and spontaneous inward currents (pacemaker currents). Pinacidil, an ATP-sensitive K^(+) channel opener, induced membrane hyperpolarization and decreased amplitude of slow waves in current clamping mode. Also, pinacidil inhibited amplitude and frequency of pacemaker currents and activated outward currents at a holding potential of -70 mV. Pinacidil effects on slow waves and pacemaker currents were blocked by glibenclamide, a specific blocker of ATP-sensitive K^(+) channel. Forskolin, an activator of adenylate cyclase, induced membrane hyperpolarization and inhibited pacemaker currents like as pinacidil and blocked by glibenclamide. Conclusions: These results suggest that ATP-sensitive K^(+) channels exist in ICC and may be play an important role in regulating gastrointestinal motility through the modulation of pacemaker activities of ICC.

Substance P의 기니피그 위 유문동 윤상근에 대한 수축 및 전기적 효과

서종옥,이승곤,김종승,전제열,여철호,윤평진 조선의대 1995 The Medical Journal of Chosun University Vol.20 No.2

햄스터에서 camostat mesilate와 proglumide가 담즙구성 성분에 미치는 영양

송영진,김성열,이상전,윤효영,장이찬,최재운 충북대학교 의과대학 충북대학교 의학연구소 1995 忠北醫大學術誌 Vol.5 No.1

콜레스테롤 담석 생성 기전을 보면 콜레스테롤이 담즙산이나 인지질에 비해 과포화되어 담석이 형성되는 것으로 알려져 있다. 색소성 담석도 CCK의 분비저하와 연관이 있는 것으로 생각되고 있으나 담즙 구성 성분의 농축과 연관이 있는 지는 알려져 있지는 않다. Kim등의 실험에서 콜레시스토기닌이 항진되어 담즙 구성 성분이 희석되었다. 만약 콜레시스토키닌 분비를 감소시킨다면 담즙 구성 성분이 농축될지는 알려져 있지 않다. 콜레시스토키닌 분비의 증감에 따라 담즙 구성 성분이 희석, 농축된다면 콜레시스토키닌과 담즙 구성 성분은 유기적으로 작용한다고 생각되어 질 수 있다 이에 저자들은 콜레시스토키닌 분비를 억제하고, 항진시키면 담즙의 구성 성분이 농축되고, 희석될 것이라는 가설을 설정하였고, 콜레시스토키닌 분비 길항제로 알려진 proglumide와 콜레시스토키닌 항진제인 camostat mesilate를 햄스터에서 투여하여 담즙구성 성분의 변화를 살펴보고자 하였다. 햄스터 80마리를 크게 4군으로 나누어 비슷한 체중을 보이는 햄스터를 짝을 지어 쥐장 1개에 4마리씩 넣어 키웠다. I군(n=20)에서는 고탄수화물식을 Ⅱ군(n=20)은 1% proglumide를 함유한 고탄수화물식이를 Ⅲ군(n=20)은 0.2% camost mesilate를 함유한 고탄수화물식이를 Ⅳ군(n=20)은 1% proglumide와 0.2% camostat mesilate를 함유한 고탄수화물식이를 2주간 투여하였다. 실험시작 2주후 24시간 금식을 시킨후 동물을 희생시켰다. 담당에서 담즙을 채취하여 구성성분을 분석하였다. 사료소모량과 체중 증가는 Ⅱ군에서 가장 높았고 Ⅲ군에서 가장 낮았다(p value=0.003). 담즙 구성 성분중 총빌리루빈, 인지질은 Ⅱ군에서 가장 높았고 Ⅲ군에서 가장 낮았다(p value=0.02, 0.03). 콜레스테롤은 Ⅱ군에서 가장 높았고 Ⅲ군에서 가장 낮았지만 통계적 유의성은 없었다(p value=0.1). 담즙산은 대조군에서 가장 높았고, Ⅲ군에서 가장 낮았다(p value=0.06). 콜레시스토키닌분비 항진제와 길항제의 투여에 따라 담즙구성 성분중 총빌리루빈치와 인지질, 콜레스테롤은 희석되고 농축되었다. 이는 콜레시스토키닌의 분비 증감에 기인하는 것으로 추정되며 처음에 설정된 가설이 일부분 증명된 것이라고 생각된다. 담즙산이 proglumide를 투여한 군에서 대조군에 비해 낮은 것은 이 약제의 용량이 적었기 때문인 것으로 추정된다. Comostat mesilate를 투여한 Ⅲ군에서 사료소모량이 감소한 것은 콜레시스토키닌의 혈중농도가 상승했기 때문인 것으로 생각된다. It has been suggested that pigment stone formation is associated with decreased secretion of cholecystokinin. It has not defined yet for decreased secretion of cholecystokinin to concentrate bile composition will be diluted if cholecystokinin increase by camostat mesilate and if bile composition will be concentrated if cholecystokinin decrease by proglumide. The present study was undertaken to define the effect in dile composition after ingestion of proglumide and camostat mesilate in hamsters. Eighty hamsters were divided into 4 groups : Group I Fed high carbohydrate diet and libitum, Group Ⅱ fed high carbohydrate diet and 1% proglumide. Group Ⅲ fed high carbohydrate and 0.2% camostat mesilate diet for 2 weeks. Hamsters was sacrificed at 3rd week. GB bile was aspirated and gallbladdder bile was analysed by kits. The level of total bilirubin and phospholipid was highest in group Ⅱ and lowest in group Ⅲ(P value=0.02, 0.003). The level of cholesterol has similar trend but it was not statistically significant(p value=0.1). The level of bile acid was lower in Group Ⅱ, Ⅲ, Ⅳ than I, but not statistically significant(p value=0.06) In conclusion, Increased secretion of CCK by camostat mesilate dilute and decreased secretion of CCK by proglumide concentrated some bile composition, this effect may be derived from gallbladder contractility and bile flow. The reason why bile acid was not in similar pattern may come from inadequate dosage of drugs.

생쥐 대장 평활근 세포에서 내향 정류성 칼륨 전류의 특성 연구

이은주,김명,정명섭,조향훈,김기훈,하현철,김준수,최석,전제열 朝鮮大學校 附設 醫學硏究所 2006 The Medical Journal of Chosun University Vol.31 No.2

Objectives: K^(+) channels play an important role in regulating cellular excitability. The aim of this study was to know whether or not inward rectifier K^(+) channel exists in colonic smooth muscle cells. Methods: Mouse colonic smooth muscle cells were isolated using collagenase, and then we recorded their membrane currents using a whole-cell patch clamp technique. Results: With 90 mM K^(+) in bath, hyperpolarization-induced inward currents from -120 mV to 20 mV with 400 ms duration at a holding potential of -10 mV showed rapid activation, inactivation and inward rectification. The inactivation showed single exponential time course. Reduction of external K^(+) to 60 mM decreased the amplitudes of the currents in whole test voltage range and shifted the reversal potential to more negative potential. The inactivation process and peak currents of hyperpolarization-induced inward currents were not affected by removing external Na^(+). External Ba^(+) blocked hyperpolarization-induced inward currents by dose-dependent manner and pure Ba^(+)-sensitive currents showed strong inward rectification. Cs^(+) also suppressed hyper- polarization-induced inward currents. Ba^(+) and Cs^(+)-induced inhibitiOn of hyperpolarization-induced inward currents was voltage-dependent, and the extent of inhibition increasing with membrane hyperpolarization. Conclusions: These results suggest that inward rectifier KU channels may exist in proximal colonic smooth muscle and may play an important role in regulating membrane potential.

An injectable cationic hydrogel electrostatically interacted with BMP2 to enhance <i>in vivo</i> osteogenic differentiation of human turbinate mesenchymal stem cells

Kim, Mal Geum,Kang, Tae Woong,Park, Joon Yeong,Park, Seung Hun,Ji, Yun Bae,Ju, Hyeon Jin,Kwon, Doo Yeon,Kim, Young Sik,Kim, Sung Won,Lee, Bong,Choi, Hak Soo,Lee, Hai Bang,Kim, Jae Ho,Lee, Bun Yeoul,Mi Elsevier 2019 Materials science & engineering. C, Materials for Vol.103 No.-

<P><B>Abstract</B></P> <P>We have designed and characterized an injectable, electrostatically bonded, <I>in situ</I>–forming hydrogel system consisting of a cationic polyelectrolyte [(methoxy)polyethylene glycol-<I>b</I>-(poly(ε-caprolactone)-<I>ran</I>-poly(L-lactic acid)] (MP) copolymer derivatized with an amine group (MP-NH<SUB>2</SUB>) and anionic BMP2. To the best of our knowledge, there have been hardly any studies that have investigated electrostatically bonded, <I>in situ</I>–forming hydrogel systems consisting of MP-NH<SUB>2</SUB> and BMP2, with respect to how they promote <I>in vivo</I> osteogenic differentiation of human turbinate mesenchymal stem cells (hTMSCs). Injectable formulations almost immediately formed an electrostatically loaded hydrogel depot containing BMP2, upon injection into mice. The hydrogel features and stability of BMP2 inside the hydrogel were significantly affected by the electrostatic attraction between BMP2 and MP-NH<SUB>2</SUB>. Additionally, the time BMP2 spent inside the hydrogel depot was prolonged <I>in vivo</I>, as evidenced by <I>in vivo</I> near-infrared fluorescence imaging. Biocompatibility was demonstrated by the fact that hTMSCs survived <I>in vivo</I>, even after 8 weeks and even though relatively few macrophages were in the hydrogel depot. The osteogenic capacity of the electrostatically loaded hydrogel implants containing BMP2 was higher than that of a hydrogel that was simply loaded with BMP2, as evidenced by Alizarin Red S, von Kossa, and hematoxylin and eosin staining as well as osteonectin, osteopontin, osteocalcin, and type 1α collagen mRNA expression. The results confirmed that our injectable, <I>in situ</I>–forming hydrogel system, electrostatically loaded with BMP2, can enhance <I>in vivo</I> osteogenic differentiation of hTMSCs.</P> <P><B>Highlights</B></P> <P> <UL> <LI> An injectable, electrostatically bonded, <I>in situ</I>–forming hydrogel system consisting of a cationic polyelectrolyte copolymer derivatized with an amine group and anionic BMP2 was prepared. </LI> <LI> The hydrogel features and stability of BMP2 inside the hydrogel were significantly affected by the electrostatic attraction between BMP2 and cationic polyelectrolyte copolymer. </LI> <LI> The electrostatically loaded hydrogel enhanced osteogenic differentiation of human turbinate mesenchymal stem cells better than one with simple loading of BMP2. </LI> </UL> </P>

Inwardly Rectifying K<SUP>⁢</SUP> Currents in Gastric Myocytes of Guinea-pig

Jae Yeoul Jun,Cheol Ho Yeum,Pyung Jin Yoon,In-Youb Jang,Nam Soo Cho,Soo Hyeong Cho,In Deok Kong,Tae Wan Kim,Insuk So,Ki Whan Kim 대한생리학회-대한약리학회 2002 The Korean Journal of Physiology & Pharmacology Vol.6 No.1

<P> To identify the presence of inwardly rectifying K<SUP>⁢</SUP> channels and its characteristics, membrane currents were measured using a whole-cell patch clamp from isolated gastric myocytes of guinea-pig. Change of external K<SUP>⁢</SUP> concentration from 5 to 90 mM induced an inward current at a holding potential of ⁣80 mV. The high K<SUP>⁢</SUP>-induced inward current was blocked by Ba<SUP>2⁢</SUP> and Cs<SUP>⁢</SUP>, but not by glibenclamide. With 90 mM K<SUP>⁢</SUP> in bath, the Ba<SUP>2⁢</SUP>- and Cs<SUP>⁢</SUP>-sensitive currents showed strong inward rectification. Ten mM TEA weakly blocked the inward current only at potentials more negative than ⁣50 mV. With 90 mM K<SUP>⁢</SUP> in bath, hyperpolarizing step pulses from ⁣10 mV induced inward currents, which were inactivated at potentials more negative than ⁣70 mV. Reduction of external K<SUP>⁢</SUP> to 60 mM decreased the amplitudes of the currents and shifted the reversal potential to more negative potential. The inactivation of inward K<SUP>⁢</SUP> current at negative clamp voltage was not affected by removing external Na<SUP>⁢</SUP>. These results suggest that the inwardly rectifying K<SUP>⁢ </SUP>channels may exist in gastric smooth muscle.