Optoperforations of Retinal Blood Vessels in an Intact Porcine Eye by Using a Femtosecond Laser-assisted Microsurgery System

M. S. Sidhu,Suk-Yi Woo,Wan Kee Kim,Heung Soon Lee,J. S. Yahng,Kyu Jin Kim,Sae Chae Jeoung,Hyun Kyu Lee 한국물리학회 2011 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.58 No.6

Femtosecond (fs) laser microsurgery is a powerful method for its potential to treat various retinal diseases, as well as to study the sub-cellular functions, because of its capability to selectively ablate a specific target (in vitro and in vivo) with minimal damage to the surrounding tissues. Here, we develop an fs-laser based microsurgery system, along with ophthalmoscope-assisted dynamic optical imaging system, for retinopathy treatment. The system is equipped with a galvano-scanner and a real-time imaging system. The laser system used for the current study consists of a regenerative amplified Ti-sapphire (λ = 810 nm) laser, delivering a 150-fs pulse at a repetition rate of 1 kHz. The illumination light from a white light-emitting diode (LED) was optically filtered to be maximally absorbed by blood, which allowed us to effectively differentiate the blood vessels from the retina surface. The estimated threshold fluences for inner limiting membrane (ILM) ablation and the primary blood vessel wall perforations within an intact porcine eye were found to be 2.6 ± 0.2 J/cm^2 and 5.0 ± 0.1 J/cm^2, respectively. The present work should be an important step in ongoing exploration of the use of femtosecond lasers for the purpose of treating retinal blood vessels.

고지방 사료와 isoacids 급여시 산유초기 비유 육성우의 비유 , 대사 , 생리적인 반응에 대한 연구

곽완섭,J. H. Herbein 한국낙농학회 1990 韓國酪農學會誌 Vol.12 No.2

고지방 사료와 isoacids에서의 비유, 대사, 생리적인 반응을 44마리의 산유초기 비유 육성우를 사용하여 실험하였다. 옥수수 사일레지 35.5%와 알팔파 혜일레지 14.4%, 농후사료 50.4%를 함유한 대조구(C)와 2%의 calcium stearate을 첨가한 구(S)와 2%의 tallow을 첨가한 구(W)와 isoacid을 첨가한 구(CI, SI, TI, WI) 등의 8가지의 실험사료를 조제하였다. 지방첨가는 일차적으로 옥수수를 대체하여 사용하였다. 지방이나 isoacid의 첨가는 유생산에 있어서 통계적유의성은 없었다(P>0.05). 지방이 첨가된 모든 사료에 있어서는 유조성분과 체중이 감소되거나(P<0.05), 감소되는 경향을 나타내었으며 반추위의 휘발성 지방산의 농도는 증가하였다. Isoacid의 첨가에 있어서 건물 섭취량과 유지율, 유지방정정유(FCM)는 증가하였다. Isoacid를 첨가한 W구에서의 건물 섭취량과 유지방 정성유(FCM)는 가장 높게 증가하였다. 지방첨가와 isoacid의 첨가는 영양소의 소화율에 영향을 끼치지 않았다. 결과적으로 고지방사료는(특히, S구) 사료내 에너지 밀도와 급여사료에서의 농후사료에 대한 조사료의 비율을 높임으로서 산유초기의 젖소에 있어서 효과적으로 이용되어졌다. 또한 isoacid을 첨가한 모든 구에서 사료의 섭취량이 증가하였고 젖소의 생산성이 증가하는 결과를 나타내었다. 특히 isoacid첨가에 대한 반응은 저생산성인 젖소에 있어서 더욱 효과적이었다. 지방첨가사료에 isoacid의 첨가는 산유초기에 있어 바람직하였다.

Cyclosporine 제제간의 생물학적 동등성 비교

김민정,박경호,신완균,이명걸,김성기,최진석 한국병원약사회 1995 병원약사회지 Vol.12 No.3

Cyclosporine(CyA) is a neutral, hydrophobic cyclic endecapeptide that has very potent immunosuppressive activity and used to prevent graft rejection and to treat autoimmune diseases. Cyclosporine is absorbed slowly and incompletely from the upper small bowel and pharmacokinetic parameters has variability depends on pharmaceutical formulation. For these reasons, pharmacokinetic evaluation of newly formulated cyclosporine is necessary to safe and rational application after transplantation. In this study, the bioequivalence in cyclosporine between the Sandimmun^(R)(SandozCo.) and Implanta^(R)(Hanmi pharma. Co.) Soft capsule was done, 14 normal volunteers(age 19 to 24 YO, 12 healthy males and 2 females) was divided into two groups, and a randomized, cross-over study was employed. Cycolosporine pharmacokinetic parameters(Cmax, Tmax, AUC) were evaluated and ANOVA was utilized for the stastical analysis in parameters, after 400㎎ of oral administration of each formulation. Cmax is 1162±350ng/㎖(C.V30%) in Sandimmun^(R)and 893±174ng/㎖(C.V 19.4%) in Implanta^(R), Tmax is 2.46±0.93hr(C.V37.8%) and 2.71±0.61hr(C.V 22.5%), and AUC is 6126±1591ng.hr/㎖(C.V 25.9%) and5594±1085ng.hr/㎖(C.V 19.4%), respectively. As the result of the data, Implanta of Hanmi has a slower absorption rate than Sndimmun of Sandos, but they are equal in the quantity of absorption. Cmax is lower, and Tmax is later in Implanta than in Sandimmun because of the slower absorption of Implanta. And these can be a considerable difference statistically, but these are no actual problem at a clinical standpoint. Conversely, the lower CV in these parameters in every individual can be a merit.

S자 결장경검사에서 용종 발견시 대장경검사의 유용성

손희정,최규완,백승운,고광철,이풍렬,이종철,오영륜,김재준 대한소화기내시경학회 1999 Clinical Endoscopy Vol.19 No.6

Background/Aims: There has been a lot of controversy regarding the significance of hyperplastic or diminutive polyps found during sigmoidoscopy, as markers for synchronous adenomatous polyps. Therefore, prospective colonoscopy was performed in subjects with distal polyps found using sigmoidoscopy to determine the association between synchronous polyps with distal polyps. Methods: A sigmoidoscopy was performed in 2,895 subjects out of 10,705 who visited Samsung Medical Center for a routine check up from Aug. 1994 to Nov. 1995. Distal polyps were found in 590 of 2,895 and colonoscopy was performed in 280 of 590. Results: Of 280 subjects, 73 (26.1%) subjects had synchronous polyps and 55 subjects (19.6%) had synchronous adenomatous polyps. 134 polyps were found during colonoscopy; adenomatous polyps were most common (70.1%): Hyperplastic polyps (18.7%) and inflammatory polyps (11.2%) were also found. A greater percentage of subjects with distal adenomatous polyps had synchronous adenomatous polyps compared with those with distal hyperplastic polyps (25.1% vs. 6.3%, p<0.05). A greater percentage of subjects with distal large polyps (>0.5 cm) had synchronous adenomatous polyps compared with those with distal diminutive polyps (≤0.5 cm) (50.0% vs. 16.1%, p<0.05). Conclusions: Adenomatous polyps found during sigmoidoscopy justify colonoscopy for synchronous polyps. However, diminutive hyperplastic polyps are not significant indicators of risk for synchronous adenomatous polyps.

40Gbps급 (4X10) VCSEL Array 구동기

김형수,정성재,김두근,이희현,최영완 중앙대학교정보통신연구소 2001 정보통신연구소논문집 Vol.3 No.2

본 논문에서는 VCSEL(Vertical Cavity Surface Emiting Laser)을 채널당 1Gbps로 동작시키고, DC Bias 전류 변화폭과 RF Modulation 전류 변화폭의 조절이 가능한 구동 드라이버를 현대 0.35㎛ 2-Poly 4-Matel CMOS공정을 이용하여 설계했다. In this paper, we present a 40 Gb/s VCSEL driver (4 x 10 channels, 1 Gbps/ch) designed and fabricated in HYNIX 0.35㎛ 2-poly 4-matel CMOS technology. The CMOS driver designed for a free space optical interconnect system is consisted of two NMOS for driving a VCSEL and protection circuit rejecting influence of electro-static discharge (ESD) or unexpected input signal with several tens voltage amplitude. Two NMOS with CMOS channel length of 0.4㎛ and width of 100 ㎛ are used for adjusting dc bias current from 0 to 27 mA and ac modulation current from 0 to 13.8 mA. Protection circuit is made of two diodes. The purpose of the protection circuit is to permit the input modulation voltage range only from 5 to 5 V.

소화성 궤양 출혈에서 열탐침 지혈법 후 재출혈의 위험인자

김영호,이석호,이상구,손희정,이규택,최규완,백승운,이종균,이준혁,고광철,이종철,김재준,류광현,이풍렬 대한소화기내시경학회 2000 Clinical Endoscopy Vol.20 No.6

Background/Aims: The precise rebleeding rate and risk factors of rebleeding after heat probe thermocoagulation in peptic ulcer patients with bleeding are not clear and still need to be evaluated. If we could identify the pre-dictors for rebleeding, the mortality rate might be loweted with early retreatment or surgery in these high risk group. Methods: The 94 patients in whom heat probe was applied were enrolled and the 18 patients with bleeding tendencies. Initial hemostasis was defined as hemostasis persisting for 24 hours post-treatment and permanent hemostasis as absence of bleeding for 7 days after therapy. Rebleedig was defined as oozing or spurting hemorrhage in the ulcer base and/or unstable vital signs and continuting tarry or bloody stool or hematemesis after therapy. Results: In 35 patients with active bleeding sign, initial hemostasis was obtained in 30 (85.7%) patients. After having achieved initial hemostasis, 9 (30.0%) patients rebled. In 41 ulcer patients with non-bleeding visible vessel, 40 cases (97.6%) achieved successful pre-vention of rebleeding. No evident complication was observed. With univariate analysis, bleeding ulcer patients with spurting and oozing hemorrhage had a higher re-bleeding rate than those with non-bleeding visible vessel. Conclusions: The heat probe thermocoagulaton is relative safe and effective procedure to protect bleeding in pectic ulcer patients with non-bleeding visible vessel, but insufficient to hemostasis in bleeding peptic ulcer patients with spurting or oozing in ulcer base. Spurting and oozing hemorrhage are the only risk factors of rebleeding after initial hemostasis with heat probe thermocoagulation in peptic ulcer patients with bleeding.

혈액투석 중인 만성 신부전 환자에서 TT Virus의 감염률과 임상적 의의

이용욱,허우성,도재혁,백승운,최문석,김소정,이준행,고광철,이풍렬,이종철,최규완,박상종,이준혁,김재준,오하영,임윤정 대한소화기학회 2001 대한소화기학회지 Vol.37 No.1

Background/Aims: TT virus (TTV) is a unenveloped, single-stranded and circular DNA virus isolated from the serum of a patient with posttransfusion hepatitis of unknown etiology. We evaluated the prevalence, risk factors, and clinical significance of TTV in patients with chronic renal failure(CCRF) undergoing maintenance hemodialysis (HD). Methods: We examined TTV DNA in serum of HD-undergoing patients and healthy controls using the nested polymerase chain reaction. Results: TTV DNA was detected in 15 (20.0%) of 75 HD-undergoing patients and 10 (13.2%) of 76 healthy controls (p$gt;0.05). The prevalence of TTV did not differ according to the duration of HD or transfusion history of the patients. The prevalence of TTV was higher in IgG anti-HBc positive patients than IgG anti-HBc negative patients (27.5% vs. 4.2%, p=0.03). There was no relationship between TTV infection and liver diseases. Conclusions: The prevalence of TTV infection in CRF patients undergoing HD was similar with that of healthy controls. These results suggest that TTV infection may share the route of transmission with HBV infection in adults.

라미부딘과 HBIg 1주일 단기 병합요법은 간이식 후 B형 간염 재발 방지에 HBIg 장기 고용량 투여요법만큼 효과적인가?

김성주,장재권,이석구,도재혁,백승운,최문석,조재원,고광철,이풍렬,이종철,최규완,박상종,이준혁,김재준,임윤정,안병훈 대한소화기학회 2001 대한소화기학회지 Vol.37 No.1

Background/Aims : The aim of this study was to evaluate whether the regimen consisted of lamivudine and one-week HBIg for HBV prophylaxis after liver transplantation is as effective as long-term therapy of high dose HBIg. Methods: Sixty-one patients with HBV infection were randomly divided into two groups: HBIg group of 31 patients and combination group of 30 patients. In the HBIg group, HBIg was given according to the standard dosing schedule. In the combination group, lamivudine was given indefinitely from at least 4 weeks before transplantation, and 10,000 IU of HBIg was given during anhepatic phase and 6 consecutive days. Results: The two groups were not different in HBeAg and HBV DNA positivity. In the HBIg group, the median follow-up of 20 long-term survivors was 12.7 months (range: 4.0 - 48.2) and that of 23 survivors in the combination group was 22.3 months (4.2 - 42.2). Hepatitis B recurred in a patient of the HBIg group and 2 of the combination group. The recurrence-free survival rate of long-term survivors was 66.7% (95% C.I., 39.5% - 93.9%) in the HBIg group and 76.0% (58.6% - 93.4%) in the combination group after 40 months. Conclusions: The combined therapy of lamivudine and one-week HBIg has an effect equivalent to long-term therapy of high dose HBIg in HBV prophylaxis after liver transplantation at a much lower cost.

NON-NATURAL EQUILIBRIUM CONTOUR DESIGN FOR RADIAL TIRE AND ITS INFLUENCE ON TIRE PERFORMANCE

J. YANG,G. L. WANG,Z. J. WAN,C. LIANG,H. C. ZHOU 한국자동차공학회 2016 International journal of automotive technology Vol.17 No.4

Two types of radial tire 11.00R20 and 385/65R22.5 are chosen as the research objects, and their carcass contours are redesigned by using Sakai Hideo’s, Frank’s and the new non-natural equilibrium contour design theories, which were based on analyzing the current non-equilibrium contour design theories of radial tire. Then the tire wear, rolling resistance and grip performance of the two radial tires designed by different non-natural equilibrium contour design theories are comprehensively analyzed with the finite element software ABAQUS. The results show that Frank’s contour design theory can reduce tire wear; the new non-natural equilibrium contour design theory can enhance tire wear, rolling resistance performance, etc. It is also found that the tire carcass contour has great influence on tire performance, especially on the tire rolling resistance. The new non-natural equilibrium contour theory provides a guidance to reduce the tire rolling resistance, and it can break through the target conflicts in tire performance. The tire with the new non-natural equilibrium carcass contour can enhance its comprehensive performance.

Assessing the Techno-Economic and Life Cycle Assessments of Ethylene Production Utilizing Methane Byproduct as an Alternative Fuel Source

Wan Nurauni Afiqah Binti Wan H,J. Jay Liu 한국에너지학회 2023 한국에너지공학회 학술발표회 Vol.2023 No.10