흰쥐 Kupffer 세포에 대한 Propofol의 작용

박세훈,지대림,성언기,김희선,송인환,박희영,김준수,이덕희,박대팔 대한마취과학회 2002 Korean Journal of Anesthesiology Vol.43 No.4

Background: Propofol has an antioxidant capacity and can be used for ischemia-reperfusion injury of the liver. However, the effects of propofol on the Kupffer cells have not been establisked. Methods: Kupffer cells were isolated and cultured from male Sprague-Dawley rats. The effects of propofol on the Kupffer cells were evaluated by a phagocytosis assay, TNF-α gene expression, and superoxide anion release after administering propofol in different concentrations on the cultured Kuprrer cells. Results: The latex bead phagocytosis by the Kupffer cells was suppressed when the Kupffer cells were exposed to propofol irrespective of concentrations. Higher propofol concentrations decreased the loss of Kupffer cells after latex bead phagocytosis. Propofol induced TNF-α mRNA expression in the Kupffer cells, but the mRNA expression level after 50㎍/ml of propofol decreased. The pattern of TNF-α mRNA expression induced by propofol was different to that induced by LPS: TNF-α mRNA was expressed continuously in the propofol-treated cells until 16 hours after exposure to propofol, whereas the level of TNF-α mRNA expression induced by LPS was evident after 2 hours and was not found thereafter. TNF-α production after propofol treatment was not higher than that of the control. Formazan presipitation did not show any qualitative differences between cells untreated or treated with propofol concentrations of 0.5, 5.0, and 50 ㎍/ml. Conclusions: These results showed that propofol might inhibit Kupffer cells. This suggests that propofol and be used for patients with ischemia-reperfusion injury of the liver. (Korean J Anesthesiol 2002; 43: 475~484)

배관내에서 난류 마찰 저항감소에 관한 연구

박설현,윤정환,서동표,정대훈,오율권 朝鮮大學校 機械技術硏究所 2000 機械技術硏究 Vol.3 No.1

Polymer drag reduction can offer a attractive way to utilize ready-made facilities in crude-oil transport system without additional large expenditure. Also, drag reduction in two phase flow can be applied to phase change system such as chemical reactor, pool and pump impeller which occurs cavitation. But the research on drag reduction in two phase flow has not been investigated. Therefore, experimental investigations have been carried out to analyze the drag reduction in the single phase and two phase flow. The objectives of the proposed investigation are primarily to identify and develop high performance polymer additives for fluid transportation. And drag reduction will be evaluated in horizontal flow by measuring void fraction, pressure drop, mean liquid velocity and turbulent intensity

표준 용매 벤젠의 Rayleigh 비의 온도 의존성

박일현,이종근,윤관한,조동환,민병길,방대석 金烏工科大學校 2000 論文集 Vol.21 No.-

The Rayleigh ratio of benzene is a very important physical constant with which the integrated scattered intensity of laser light scattering can be converted into the absolute value. In this study temperature dependence of Rayleigh ratio of this solvent has been investigated with two different methods in the temperature range of 25-75℃. It was found that in the direct measurement the non-linear behavior of its Rayleigh ratio were observed as increasing temperature even if the scattering volume correction was applied to the scattered intensity of benzene. However the result of indirect measurement based upon the invariance of molecular weight of standard polystyrene polymer for any polymer solution temperature showed us that its temperature dependence up to 75℃ could be expressed with the Benoit's linear equation rather than the non-linear one. It seems that the scattered intensity in direct method has more complicate contributions at the elevated temperature. Further research works are necessary in order to solve such discrepancy clearly.

국소 광적응 기능을 가지는 윤곽검출용 32×32 방사형 CMOS 시각칩의 설계 및 제조

박대식,박종호,김경문,이수경,김현수,김정환,이민호,신장규 한국센서학회 2002 센서학회지 Vol.11 No.2

국소 광적응 기능을 가지는 윤곽검출용 시각칩을 픽셀수 32x32의 방사형 구조로 CMOS 공정기술을 이용하여 설계 및 제조하였다. 생체의 망막은 넓은 범위의 입력 광강도에 대해서 물체의 윤곽을 검출할 수 있다. 본 연구에서는 시세포, 수평세포, 쌍극세포로 이루어진 망막의 윤곽검출 기능을 모델링하여 윤곽검출용 인공시각칩을 설계하였다. 국소 광적응을 위해, 입력 광강도에 따라 수용야의 크기를 국소적으로 바뀌게 하였다. 아울러 단위셀을 방사형으로 배치함으로써 영상데이터의 양을 감소시킴과 동시에 칩의 중심부분으로 갈수록 해상도가 높아지도록 설계하였다. 설계된 칩은 0.6 ㎛ double-poly triple-metal 표준 CMOS 공정기술을 이용하여 제조되었으며. HSPICE 시뮬레이션으로 성능을 최적화 시켰다. A 32x32 pixels foveated (linear-polar) stucture retina chip with the function of local-light adaptation for edge detection has been designed and fabricated using CMOS technology. Human retina can detect a wide range of light intensity. In this study, we use the biologically-inspired visual signal processing mechanism that consists of photoreceptors, horizontal cells, and bipolar cells in order to implement the function of edge detection in the retina chip. For a local-light adaptive function, the size of receptive field is changed locally according to the input light intensity. The spatial distribution of sensing pixels in the foveated retina chip has the advantages of selective reduction of image data and good resolution in central part to carry out the elaborate image processing with still enough resolution in the outer parts. The designed chip has been fabricated using standard 0.6 ㎛ double-poly triple-metal CMOS technology and optimized using HSPICE simulator.

사비의 교정에 있어서 내시경의 이용

박대환,김태모,이재욱,송철홍,한동길,안기영 大韓成形外科學會 1998 Archives of Plastic Surgery Vol.25 No.1

Owing to the complexity of the deviated structures and the septal deformities accompanying the external nasal deformities, the complete correction of the deviated nose is regarded as a difficult one. The approach to the nasal bone and osteotomy in classic corrective rhinoplasty is almost blind technique, where the results depends on the feeling by surgeon's hand. To overcome these drawback, endoscopic-assisted corrective rhinoplasty and septoplasty performed for 8 cases of deviated nose between January 1996 and May 1997. Average follow-up period was 10 months. All patients were evaluated by symmetrical nasal pyramid, recurrence of the bony deflection and septal deviation. The postoperative courses were satisfactory in most of cases with few complications. It appears that endoscopic control during corrective rhinoplasty and septoplasty is a big step toward obtaining better results in bony and cartilage resection with extreme precision under monitor control and magnification. This technique is not an open approach but permits one to see more of the nasal skeleton and bony septum what is causing deformity, and the immediate effect of the corrective measures used. The use of endoscope in corrective rhinoplasty will provide expanded field of vision, direct manipulation of lesions, and better aesthetic an6 functional results.

RFID 적용 원편파 패치 안테나의 설계

박규대,김환용 원광대학교 대학원 2009 論文集 Vol.42 No.-

In this paper, both circularly polarized patch antenna and modified loop antenna were investigated for ultra high frequency of 908.5MHz-914MHz radio frequency identification systems adopted to reader and transponder, respectively. The CP characteristics for reader antenna was realized by using truncation at the edge of patch and the bandwidth of resonance frequency was also enhanced with longer distance between ground plane and radiating patch. Futhermore, overall patch size was reduced to 1.73 times owing to narrow slit consist of inductance component at the radiating patch on RF-4 substrate with dielectric constant of 4.4 materials. The measurements results of fabricated prototype shows that antenna gain of 7.9dBi, 3dB beam width at radiation pattern of 87° and 105° for vertical and horizontal directions, respectively, with 15dB front-to-back ratio. The results shows that the proposed antenna features a compact size, wide impedance bandwidth, moderate gain, and excellent axial ratio. This antenna is well suitable for the applications in RFID readers.

수지말단부 손상의 분류와 재건

박대환,한동길,안기영 대한성형외과학회 1992 Archives of Plastic Surgery Vol.19 No.3

Finger tip injuries are in increasing tendency and the treatment must be focused toward preserving length and providing normal sensitivity. The 61 injured digits distal to DIT joint in 49 patients were managed in various procedures from May, 1990 to June, 1991. The authors classified the injured digits into 6 groups and selected the best surgical procedures according to the extent of the injuries. The 6 groups were : A. Volar skin and pulp loss without exposed bone B. Large volar skin and pulp loss with exposed distal phalanx C. Straight-transecton involving nail bed injury. D. Dorsally directed injury with little remaining nail bed E. Germinal matrix injury F. Injury at DIT joint level Tentatively recomonended surgical procedures by the extent of injury were : 1. Secondary intention or skin graft for level A 2. Local flap coverage for level B 3. Composite graft or Local advancement flap for level C 4. Local flap coverage or primary closure after bone shortening and residual nail ablation for group D 5. Micro-replantation or distant flap or local flap according to the state of the injury for group E and F

한랭작업 근로자들의 건강위해에 관한 연구

박호추,정설미,문덕환,이종태,김대환,김정호,최재일,황용식,이용희,이채언 大韓産業醫學會 1999 대한직업환경의학회지 Vol.11 No.1

In order to evaluate the status of cold exposure and its health hazards of workers at cold storage workplaces and to provide basic data for effective health care, the author measured core temperature and also observed clinical symptoms and signs, past and present history, and general health examination data on 99 cold exposed workers for exposure group and 96 non-exposed workers for control group working at 2 food refrigerating companies in Pusan area from January 6, 1998 to February 24, 1998. The results were as follows: 1. There was statistically significant difference in water intake between the exposure and control group and increased urine volume, urine frequency in exposure group without statistically significant difference. 2. Past and present illness in exposure group were hypertension (18.2%), hepatopathy (8.1%), gastro-intestinal disease(7.1%), arthritis (4.0%), intervertebral disc herniation(4.0%), and so on, and hypertension, arthritis was statistically significant difference compared to control group. 3. Symptoms in exposure group were fatigue(89.9%), headache (64.6%). drowsy(63.6%), neck stiffness(59.6%), excessive food intake(59.6%). general weakness(58.6%), hunger(58.6%), numbness(54.5%), and so on, and there was statistically significant difference between the exposure and control group except fatigue, drowsy. 4. As results of clinical test abnormality rate of the systolic, diastolic blood pressure and electrocardiogram were significantly higher in exposed group than control. 5. Core temperature in exposure group was statistically significantly lower than control group and the highest statistically significant inverse correlation with the working hours and working frequency of daily mean cold storage. As above results, the author suggested that the further studies should be conducted to evaluate the health status of workers about chronic health effects in cold workplaces and to establish effective health care methods for them.

내시경을 이용한 관골궁골절 정복술

박대환,이재욱,장경수,송철홍,한동길,안기영 大韓成形外科學會 1998 Archives of Plastic Surgery Vol.25 No.1

Although the zygomatic arch can be employed as a key landmark to the accurate alignment of a displaced zygoma fracture, it has been traditionally avoided because of the need for a bicoronal incision. Exposure of the zygomatic arch by means of the conventional bicoronal incision has several possible disadvantages, including an increased risk of blood loss, alopecia, loss of sensation posterior to the incision, and traction palsy of the facial nerve. Endoscopic-assisted exposure of a zygomatic arch can largely obviate the disadvantages of a bicoronal incision and yield this site accessible to reduction and internal fixation in the routine treatment of displaced zygoma fractures. 9 cases of endoscope-assisted open reduction of zygomatic arch fracture and 3 cases of internal fixation of a moderately displaced zygoma fracture are presented. To accomplish this technique, a rigid 4 mm, 30 degree down-angled endoscope, trocar and cannula, endoscopic forehead lift instrument were used. The postoperative courses were satisfactory with few complications. The use of endoscope in the treatment of zygoma reduction provided an expanded field of vision, direct manipulation of lesions, minimal postoperative scar. In particular, exposure and fixation of the zygomatic arch were performed without the need for a bicoronal incision.

F. Du¨rrenmatt의 희곡 "Romulus der Groβe"연구 : 時代批判의 問題를 中心으로 Unter besonderer Beru¨cksichtigung der Zeitkritik

박대환 조선대학교 외국문화연구소 1987 外國文化硏究 Vol.10 No.1