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백서의 가역성 뇌허혈 모형에서 재관류 시간에 따른 뇌경색 크기의 변화
정병우,최병연,조수호,김오룡,배장호,김성호,Jung, Byoung Woo,Choi, Byung-Yon,Cho, Soo-Ho,Kim, Oh-Lyong,Bae, Jang-Ho,Kim, Seong-Ho 대한신경외과학회 2000 Journal of Korean neurosurgical society Vol.29 No.9
Objective : The purpose of the present study was to determine the appropriate time of clinical intervention by observing and analyzing the changes in the size of infarct, penumbra and cerebral edema and the extend of neurological deficit due to reperfusion damage according to time in a reversible cerebral ischemic model of reperfusing blood flow after inducing ischemia by maintaining middle cerebral artery occlusion for 2 hours(h) in rats. Methods : The rats were divided according to reperfusion time into control group(0 h reperfusion time) and experimental groups(0.5, 1, 2, 3, 4, 5, 6, 12, and 24 h of reperfusion time). Results : Changes in the size of infarction due to reperfusion damage were 0.93, 1.48 and 1.16% at 0.5, 1 and 2 h after reperfusion, respectively, and although a statistical significance was not present compared to 1.35% of the control group, damages increased drastically up to 6 h(6.64%), and the size increased were 6.65 and 6.78% at 12 and 24 h, respectively. Also there was no significant difference after 6 h up to 24 h in the size of infarction. In the areas where infarction occurred, reperfusion damage increased significantly with time in cortex than in subcortex. Accordingly, the size of penumbra area also showed a statistically significant decrease from 2 h up to 6 h after reperfusion, and 6 h after reperfusion, the area almost disappeared, becoming permanent infarction. Thus, reperfusion damage showed a significant increase from 2 h up to 6 h after reperfusion, and became steady thereafter. As for the mean ratio of the extend of cerebral edema, the control group and reperfusion 0.5 h group were 1.073 and 1.081, respectively ; up to 2 h thereafter, the ratio decreased to 1.01 but increased again with time ; and in reperfusion 12 h and reperfusion 24 h, the ratios were 1.070 and 1.075, respectively, showing similar size with that of control group. As for neurological deficit scores, the score of the control group was 2.67, that of reperfusion 2 h was 2, those of reperfusion 3 h and 6 h groups were 3.2 and 3.8, respectively, and those of reperfusion 12 h and 24 h groups were 4.2 and 4.6, respectively. Thus, as for the test results, the neurological deficit increased with time 2 h after reperfusion, and in reperfusion 12 and 24 h groups, almost all the symptoms appeared. Conclusion : As shown in these results, although the changes in the size of infarction due to reperfusion damage did not increase up to 2 h after reperfusion in the experimental groups compared to the control group, damage increased significantly thereafter up to 6 h, and the size remained about the same from 6 h to 24 h after reperfusion, becoming permanent infarction ; thus, the appropriate time of intervention according to the present study is at least 6 h before after maintaining reperfusion, including the time of cerebral artery occlusion.
개보수 대상 건물의 비용 측면에서의 효율성 평가에 관한 연구 - 바닥 마감재를 중심으로 -
김상용,정병우,강경인,Kim, Sang-Yong,Jung, Byung-Woo,Kang, Kyung-In 한국건축시공학회 2003 한국건축시공학회지 Vol.3 No.4
The purpose of this study is to evaluate efficiency by the Life Cycle Cost(LCC) analysis of floor covering materials for remodeling. This study has been performed as a case study. The LCC analysis is a technique which takes account into both initial-future costs and benefits of an investment over some period of time. LCC is important in commercial decision making because it provides improved assessment of the living-term cost effectiveness of construction projects as well as alternative economic methods that focus on initial costs. For LCC analysis and comparison, the present value technique is used. The results of this study are summarized as follows; (1) A LCC analysis model of floor covering materials is suggested through a case study (2) As a result of LCC case study, the type of sheet is analysed more economical than that of tile in floor covering materials.
백서의 가역성 뇌허혈 모형에서 저체온의 효과와 적용시기
최병연,정병우,송광철,박진한,김성호,배장호,김오룡,조수호,김승래,Choi, Byung-Yon,Jung, Byung-Woo,Song, Kwang-Chul,Park, Jin-Han,Kim, Seong-Ho,Bae, Jang-Ho,Kim, Oh-Lyong,Cho, Soo-Ho,Kim, Seung-Lae 대한신경외과학회 2000 Journal of Korean neurosurgical society Vol.29 No.2
Objective : We studied to clarify the effective time zone of mild hypothermic neural protection during ischemia and/or reperfusion after middle cerebral artery occlusion. Methods : In a reversible cerebral infarct model which maintained reperfusion of blood flow after middle cerebral artery occlusion for two hours, the size of cerebral infarction, cerebral edema and the extent of neurological deficit were observed and analyzed for comparison between the control and the experimental groups under hypothermia($33.5^{\circ}C$). The temporalis muscle temperature was reduced to $33.5^{\circ}C$ by surface cooling for two hours during middle cerebral artery occlusion for study group I. The following groups applied hypothermia for two-hour periods after reperfusion : group II(0-2 hours), group III(2-4 hours), and group IV(4-6 hours). They were rewarmed to $36.5^{\circ}C$ until sacrified at 2, 4, 6, 12, and 24 hours after reperfusion. Control group was maintained at normothermia without hypothermia. Results : In the experimental groups with hypothermia, the average value of the size of cerebral infarction($mean{\pm}SD$) was $1.97{\pm}1.65%$, which was a remarkable reduction over that of the control, $4.93{\pm}3.79%$. In the control, a progressive increase was shown in the size of infarction from point of reperfusion to 6 hours after reperfusion without further changes in size afterward. Intra-ischemic hypothermia(group I) prevented ischemic injury but did not prevent reperfusion injury. Group II examplified the most neural protective effect in comparison to the control group and group IV(p<0.05). The cortex was more vulnerable to reperfusion injury than the subcortex. Mild hypothermia showed more neural protective effects on the cortex than subcortex. Conclusion : The most appropriate time zone for application of mild hypothermia was defined to be within four hours following reperfusion.
전우열,배장호,정병우,김성호,김오룡,최병연,조수호,Jeon, Woo-Youl,Bae, Jang-Ho,Jung, Byoung-Woo,Kim, Seong-Ho,Kim, Oh-Lyong,Choi, Byung-Yon,Cho, Soo-Ho 대한신경외과학회 2001 Journal of Korean neurosurgical society Vol.30 No.1
Objective : The purpose of the present study was to examine neurologic changes, fusion rate and degree of kyphosis from the surgical results of those patients who underwent multi-level anterior interbody fusion and internal fixation. Methods : Among 63 cases of the patients who received multi-level anterior interbody fusion and internal fixation in 5 years between 1995 to 1999 at the neurosurgery department, we performed a retrospective study in 52 cases that could be followed up with dynamic view imaging ; the results were compared and analyzed. The analysis was based on the results of history taking, physical findings and radiologic findings, and Odom criteria were used to classify those cases with neurologic changes. Results : Among those 52 cases in whom the follow-up was possible for at least a year and dynamic view imaging was possible, bone fusion was seen in 93% of the trauma cases and 95% in the non-trauma cases and overall bone fusion was observed in 94% of the cases. Bone fusion was seen in 93% of the autobone cases, 95% of the allobone cases, and 94% of the Mesh cases. Radiologic changes were observed by comparing the lateral view after surgery ; kyphosis was seen in 53% of the autobone cases, in 70% of the allobone cases, and in 35% of Mesh cases ; in 45% and 60% of the non-trauma cases and trauma cases, respectively ; and in 55% of the 2 level fusion cases and 46% of the 3 level fusion cases. Neurologic changes classified according to Odom criteria showed excellent result in 48% of all the cases, good in 23%, fair in 4%, and poor in 25%. Conclusion : Even those cases with multi-level fusion, a high fusion rate could be obtained by performing anterior interbody fusion and internal fixation ; those cases with kyphosis were related more with the presence or absence of posterior compartment injury rather than the fusion level ; and those trauma cases showed not much difference in the fusion rate compared with non-trauma cases but had a high possibility of kyphosis.
Homogeneous precipitation method를 통한 나노 YAG : Ce 형광체 합성과 광학 특성
이철우,권석빈,지은경,송영현,정병우,김은영,정몽권,윤대호,Lee, Chul Woo,Kwon, Seok Bin,Ji, Eun Kyung,Song, Young Hyun,Jeong, Byung Woo,Kim, Eun Young,Jung, Mong Kwon,Yoon, Dae-Ho 한국결정성장학회 2017 한국결정성장학회지 Vol.27 No.1
본 연구에서는 homogeneous precipitation method를 통하여 구형의 단분산(monodispersed) YAG : $Ce^{3+}$를 합성했다. 단분산 YAG : $Ce^{3+}$의 전구체를 합성하는 과정에서 aluminum ion들이 먼저 석출되어 aluminum 화합물을 형성하고 후에 yttrium 화합물들이 aluminum 화합물들의 표면에서 석출된다. 합성된 전구체를 파우더형태로 얻기 위해 건조과정을 거치는데, oven에서 건조했을 때 보다 동결건조기에서 건조했을 때 비교적 구형의 단분산 YAG : $Ce^{3+}$ 입자를 얻을 수 있었다. 하소 과정에서 공정을 진행하는 온도로서 $1100^{\circ}C$와 $1200^{\circ}C$를 비교해 보았다. 실험 결과 $1200^{\circ}C$의 온도로 상압에서 6시간 동안의 하소 과정을 진행하였을 때 400~500 nm 입자크기를 가진 단분산된 구형의 나노 YAG : $Ce^{3+}$ 입자가 합성되었다. In this study, spherical monodispersed cerium-doped yttrium aluminum garnet (YAG : $Ce^{3+}$) phosphor particles were synthesized via homogeneous precipitation method using the mixed solution of yttrium nitrate, cerium nitrate, aluminum nitrate, ammonium aluminum sulfate, and urea as a precipitant. During the process of precursors of monodispersed YAG : $Ce^{3+}$, aluminum ions which form spherical aluminum compounds precipitated first and yttrium compounds precipitated onto the surface of the existing spherical aluminum compounds. Drying process using lyophilization could obtain monodispered spherical YAG : $Ce^{3+}$ particles compare to using oven. The thermal calcination process of YAG : $Ce^{3+}$ precursors under the temperature of $1200^{\circ}C$ for 6 h was enough to obtain 400~500 nm sized YAG particles with pure YAG phase.
고출력 LD 용 형광체 세라믹 플레이트의 두께에 따른 광학 특성
지은경,이철우,송영현,정병우,정몽권,윤대호,Ji, Eun Kyung,Lee, Chul Woo,Song, Young Hyun,Jeong, Byung Woo,Jung, Mong Kown,Yoon, Dae-Ho 한국결정성장학회 2016 한국결정성장학회지 Vol.26 No.2
본 연구에서는 고출력 자동차 헤드램프용 LD 에 적용 가능한 garnet 구조의 YAG : Ce 형광체 세라믹 플레이트를 제작하고 광학 특성을 분석하였다. 액상법을 이용하여 단분산된 구형 나노 YAG : Ce 입자를 합성하고 이를 $Al_2O_3$와 혼합하여 형광체 세라믹 플레이트를 제작하였다. 형광체 세라믹 플레이트의 두께를 $75{\mu}m$, $100{\mu}m$로 조절하여 두께에 따른 광 변환 효율, 열 소광(Thermal quenching), 휘도 및 색온도의 광학 특성을 비교하였다. 실험 결과, 광 변환 효율의 감소 폭은 모두 25 % 감소하였고, 열 소광, 최대 광 변환 효율 값, 최대 휘도 값은 $100{\mu}m$ 일 때 더 높게 나타났다. In the present paper, garnet structured $Y_3Al_5O_{12}:Ce^{3+}$ (YAG : Ce) ceramic phosphor plate (CPP) for high power laser diode (LD) was prepared and optical properties were analyzed. We synthesized monodispersed spherical nano-sized YAG : Ce particles by liquid phase method, fabricated phosphor ceramic plate with the addition of $Al_2O_3$. $75{\mu}m$ and $100{\mu}m$ thick YAG : Ce CPPs were compared in terms of the factors of conversion efficacy, thermal quenching, luminance and correlated color temperature (CCT). In conclusion, conversion efficacy decreased by 25 % in both samples and $100{\mu}m$ thick sample provides better optical properties of thermal quenching, maximum light conversion efficacy and maximum luminance value.