항공 응용 분야 : CRLH 전송선로의 비선형 위상 특성을 이용한 이중대역 평형 믹서

김영 ( Young Kim ),윤영철 ( Young Chul Yoon ),정연우 ( Youn Woo Jung ) 한국항행학회 2011 韓國航行學會論文誌 Vol.15 No.1

본 논문은 비선형 위상 특성을 갖고 있는 CRLH 전송선로를 이용하여 이중대역 평형 믹서를 제안한 것이다. 이 메타 재질 구조의 믹서는 이중대역에서 낮은 LO 누설 전력과 높은 RF-LO 고립도를 갖고 있어, LO와 RF 경로에 추가적인 여파기가 필요하지 않는다. 이 평형 믹서는 이중대역에서 동작하는 발룬과 윌킨슨 분배기를 이용하여 구현하였으며, 이중대역 특성은 CRLH 전송선로의 비선형 위상 특성을 이용하였다. 제안한 메타 재질을 이용한 평형 믹서는 실험을 결과를 통해서 증명하였으며, 870 MHz와 1660 MHz의 주파수에서 동작하도록 제작하여, 870 MHz에서 15.2 dB, 1660 MHz에서 21.2 dB의 변환 손실을 얻었다. This paper presents a dual-band balanced mixer using nonlinear phase characteristic of composite right/left-handed (CRLH) transmission line. This metamaterial structure provides low LO leakage and high RF to LO isolation without additional filters for LO and RF path. The balanced mixer consists of balun and Wilkinson divider with dual-band characteristic of unit-cell which behaves like a CRLH metamaterial. Experimental results are used to verify the proposed metamaterial functions. The balanced mixer design results in an operating frequency of 870 MHz and 1660 MHz with an optimum mixer conversion loss of 15.2 dB at 870 MHz and 21.2 dB at 1660 MHz.

신경과학 연구를 위한 실험쥐 해마의 기관형적 절편 배양의 유용성

홍순철(Soon Cheul Hong),윤영철(Young Chul Youn),이동근(Dong Keun Lee),김동욱(Dong Wook Kim),채수안(Soo Ahn Chae) 대한소아신경학회 2003 대한소아신경학회지 Vol.11 No.1

목 적 : 실험쥐 해마부위의 기관형적 절편 배양을 정립하여 신경계의 외부자극에 대한 생리학적, 병리학적 반응을 규명하는 신경과학 연구에 관한 유용성을 알아보고자 하였다. 방 법 : 생후 8-9일된 실험쥐의 대뇌를 적출한 다음 dissection microscope 하에서 해마부위를 분리한 후 tissue chopper를 이용하여 450 µm 두께로 절편을 만든 후, Gahwiler's media가 담겨진 6 well plates의 Millicell membrane inserts로 옮겼다.36℃의 humidified CO incubator로 옮긴 후 2-3일 간격으로 배양액을 갈아주며 배양하였다. 이후 일정 배양기간별로 조직 및 신경원의 변화를 광학 현미경으로 관찰 후 Image analysis system을 이용하여 분석 평가하였다. 결 과 : 1) 배양 7일째부터 제대로 된 구조와 적절한 성숙도를 보이기 시작하여 배양 14일경 충분히 성숙된 구조와 신경원을 관찰 할 수 있었다. 2) 배양 4주 이후까지도 조직 배양을 유지할 수 있었으나 장기간 배양 시 감염 및 오염 기회가 높았으며 조직이 배양되면서 절편의 두께가 얇아져, 냉동 절편과 파라핀 블룩을 이용한 염색에 어려움이 있었다. 3) 염색 상 배양 2주 이후의 조직에서 치아이랑, CA 1, 2, 3 지역의 신경원의 모양 및 분포 양상에 커다란 차이가 없었다. 4) 해마부위의 기관형적 절편 배양에서 아교세포와 신경원세포가 자라고 있음을 확인했으며 생체 내 해마에서 발생하는 추체 세포, 과립세포 2종류의 신경원을 발견하였다. 5) Western blotting을 이용하여 NeuN 단백을 확인하였으며, NeuN 단백의 양은 배양 6일째부터 증가하기 시작하여 배양 9일째까지 최고 정점에 이른 후 배양 12일 이후 감소하기 시작하였다. 결 론 : 상기 결과들은 실험쥐 해마의 기관형적 절편 배양이 신경과학의 형태학적 및 분자 생물학적 연구를 위한 유용한 모델이 될 수 있을 것으로 생각된다. Purpose : Organotypic slice cultures are suitable for morphological and electrophysiological studies, and a valuable method to evaluate physiological and pathological responses to external stimuli. This study was designed to establish a method and to assess its values of organotypic slice cultures of rats' hippocampus for neuroscience research. Methods : 8-day-old neonatal Sprague-Dawley rat's brain was dissected quickly and the brain was removed. Both of the hippocampi were dissected out in Petri dishes and placed on a chopper or tissue cutter with Gey's balanced salt solution(GBSS). Slices of 450µm were cut and separated by adding of a drop of GBBS. Extra GBBS was aspirated. Transfer tissue slices of Millicell membrane were inserted in six-Well plates containing 1 mL of warmed Gahwiler's media. Six-well plates were placed in an incubator at 36℃ with 5% CO and the media were changed regularly every 2 to 3 days. Some tissue were placed in 4% paraformaldehyde for staining and other were placed in Phosphate buffered saline(PBS) for 30 min for Western blotting. Then, we stained the free-floating, cryocutting or paraffin embedded slices with H&E or the days of 6, 9, 14 and 24 in vitro(DIV), and evaluated any changes of tissues and neurons by an image analysis system Results : Hippocampal cultures had well-defined cell body layers of dentate gyrus, CA1, 2, 3, and 4 as early as the day of 6 in vitro(DIV). After 14 DIV, the cultures became gradually thinner from 450 µm to 150 µm. After 21 DIV, there were migrations of cells away from the margins of the slices and degenerative changes of some neuronal cells occurred. But pyramidal cells always were organized in well-defined cellular layer even after several weeks in the culture. Therefore, the best results were obtained by culturing slices of 6 to 14 DIV. Slice cutures was maintained after 4 weeks in vitro, but the opportunity of contamination and infection increased as the periods of cultures trolonged. In staining, after any tissue was cultured in 2 weeks in vitro, no differentiation of the morphology and distribution in dentate gyrus, CA1, 2 and 3 were seen. In organotypic slice culture of rats' hippocampus, we witnessed growth of glial and neuronal cell, and found pyramidal and granular cells. NeuN proteins were identified by Western blotting, and the density of NeuN protein bands was at the maximum value on the day of 9 in vitro. Conclusion : Since the organotypic slice cultures of rats' hippocampus were similar to the hippocampus in vivo in terms of anatomical and cellular morphology, it will become a valuable method for neuroscience research.

진행성 간암환자에서 간이식 수술의 적응증 확대

이경근(Kyung Keun Lee),윤영철(Young Chul Youn),황정기(Jung Ki Hwang),박정현(Jung Hyun Park),김지일(Ji Il Kim),유영경(Yung Kyung Yoo),문인성(In Sung Moon),김동구(Dong Goo Kim) 한국간담췌외과학회 2009 한국간담췌외과학회지 Vol.13 No.3

Purpose : The purpose of this study was to evaluate the possibility of expanding the indication for living donor live transplantation (LDLT) for treatment of hepatocellular carcinoma(HCC), beyond the Milan criteria without compromising patient survival. Methods : This was a retrospective study of 5patients (36.4%) that had undergone LDLT, beyond the Milan criteria, among 143 patients with HCC. The study was conducted in aptients treated by the Department of Surgery, Catholic University of orea from Oct 2000 to May 2008. We evaluated the survival curve, prognostic factors for survival and compared survival between our new criteria and Milan criteria. Results : The 5 year patient survival and disease free survival rate in patients treated with LDLT beyond the Milan criteria were 50.2% and 61.9%, respectively. The prognostic factors affecting disease free survival and patient survival included serum AFP level, tumor size, vascular invasion, and lumor cell differentation on univariate analysis. In multivariate analysis, AFP (200 ng/mL), tumor size (7cm) and vascular invasion had significant influence on survival and disease free survival. According to our new criteria (size<7 cm, AFP <200 ng/mL), 88.1% of our patients were included compare to the 63.6% that would have been if limited to the Milan criteria. With both factors met, the survival was comparable to the survival of Milan criteria (63.7% on our criteria and 78.2% on Milan criteria at 5 years)(P=0.103). Conclusion : A tumor size <7cm and a AFP <200 ng/mL appear to be useful cut-off values, beyond that criteria required by Milan. An analysis according to our criteria showed an acceptable survival outcome. Further verification of these findings by a large volume or prospective study is required for widespread adoption of our new criteria.

천연 소재 BF-7의 어린이 장ㆍ단기 기억력 향상 효과

김도희(Do-Hee Kim),김옥현(Ok-Hyeon Kim),여주홍(Joo-Hong Yeo),이광길(Kwang-Gill Lee),박금덕(Geum Duck Park),김대진(Dae-Jin Kim),정윤희(Yoon-Hee Chung),김경용(Kyung-Yong Kim),이원복(Won-Bok Lee),윤영철(Young Chul Youn),정윤화(Yoonhwa C 한국식품영양과학회 2010 한국식품영양과학회지 Vol.39 No.3

본 연구는 BF-7이 어린이의 장기 및 단기 기억을 현저하게 촉진시킴을 보여주었다. 기존 임상 시험 결과를 통해 입증된 바와 같이 천연 소재인 BF-7의 안전성을 고려할 때, BF-7은 어린이 장기 및 단기 기억력, 기억유지도 및 기억의 효과적 활용 등 전반적인 기억 수행 능력 향상에 도움을 주는 매우 안전하면서 효과가 탁월한 천연소재임을 확인하였다. It has been shown that BF-7 enhances short- and long-term memory and attention in normal person. BF-7 was addressed to clinical study for children if BF-7 is also effective to children, since accumulated verification of safety and effectiveness is needed for young ages, in special. We administered BF-7 and a placebo control to two different groups of children (7-12 years old, 9.78 on averages). Their memory enhancement was tested with Rey-Kim Memory Test for Children before and after the administration of BF-7 and a placebo, in a double blinded way. The results showed that long- and short-term memories were significantly improved by the administration of BF-7. Interestingly, the degree of memory preservation, the ability of memory application and awareness of complex thing were also significantly improved. These results indicate that BF-7 is a promising substance from natural resource improving learning and memory of children as well as cognitive function of adults

흉부대상포진 환자의 근전도검사소견

윤영철,권오상 중앙대학교 의과대학 의과학연구소 1996 中央醫大誌 Vol.21 No.1

Typical herpes zoster(HZ) presents as a vesicular eruption along sensory dermatomes. It is less well known that HZ cause motor paralysis. The occurrence of motor deficit complicated with HZ has been reported since 1866, but the frequency of motor involvement is very variables, ranging 0.5 to 31.0%. There are few electromyographic studies in HZ patients who are not complicated with motor symptom. The purpose of this study is to investigate the extent of motor involvement in thoracic HZ, by means of electromyography(EMG). We performed EMG of paraspinal muscles of several segments around involved dermatomal level, ipsilateral to skin lesions. A total of 81 patients(31 men, 50 women ; mean age : 53.4, ranging 14 to 85 years) were subjected, who had no clinical weakness. mean interval was 9.7 days between skin eruption and EMG studies. The motor involvement revealed by denervation potentials on EMG study was seen in 44(54.3%) of 8 patients. There was no significant difference between both sexes, although the rate of motor involvement was slightly higher in men than in women. There was no statistical relationship between age and motor involvement. In 44 cases with motor involvement on EMG, denervation potentials were observed more widely beyond the involved dermatomes. In conclusion, subclinical motor involvement is rather frequent accompaniment with thoracic HZ, although clinical motor symptom is very rare. This study also suggests that motor involvement, when occurs, tend to be wider in distribution than dermatomal involvement and could develop at the same time as the onset of skin lesion of even earlier.

치매를 나타내지 않는 인슐린 비의존성 당뇨환자에서 인지유발전위

윤영철,하삼열,신동선,한승호,권오상 대한치매학회 2002 Dementia and Neurocognitive Disorders Vol.1 No.2

Background : Cognitive impairment has been recognized as a possible complication of diabetes mathtus (DM). It is well known that event-related potentials (ERPs) and Hopkins verbal Leaming Test (HVLT) are clinical tools in the evaluation of the patients who suffer from disorders of congnition. The present study was designed to investigate the effect of diabetes meltus and its complications on the ERPs nad HVLT. Methods : A cross sectional comparative study of the 51 normal controls and the 40 non-demented NIDDM patients who had no neurologic deficits was performed. The study consisted of a neurologic examination. Short form-Samsung Dementia Questionnaire brain CT. ERPs, HVLT, nerve conduction study, fundus examination and biochemical study Results : The P300 latencies of the DM patients and the normal control groups were well correlated with age Compared with controls, the P300 latencies of the patients were signficantly prolonged In NIDDM patients, prolonged P300 latencies were not associated with neuropathy but with retinopathy (p<.05) P300 latencies of NIDDM were correlated with immediate free recail of HVLT. There were no significant differences in scores of HVLT components between NIDDM and normal control group Conclusions : NIDDM patients without overt dementia or other CNS disorders may have a subtle cerebral malfunction, which can be detected by ERPs but not by verbal learning test. Therefore ERPs might be a useful tool to evaluate subtle cognitive dysfunction It is suggested that the factors responsible for genesis of this cerebral malfunction are not influenced by short-term metabolic dysfunction and may be different from those responsible for the DM neuropathy.

Does Cerebellar lschemic Stroke Affect the EEG?

Youn, Young Chul,Oh, Hyung Geun,Kwon, Oh Sang 중앙대학교 의과대학 의과학연구소 2002 中央醫大誌 Vol.27 No.3-4

We have analyzed EEG results to investigate electrical crossed cerebellocerebral diaschisis(CCCD), contralateral cerebral dysfunction of the background astivity in EEG records in patients with cerebellar ischemia. The EEG and brain MRI of 14 oatients with unilateral cerebellar stroke were studied. MRIs were performed within five days(1.86±1.17) and conventional EEGs were performed within 20 days(6.93±6.09) after the symptom onset. The EEG from four of the 14 patients showed focal slow waves in the contralateral hemisphere to the cerebellar lesion. They comprised two patients with superior and middle cerebellar peduncle infarction, one patient with a middle cerebellar peduncle infarction and one patient with a cerebellar hemispheric infarction. There was no significant difference between patients with CCCD and those without CCCD, in terms of the patients'age and the interval from the onset of neurological symptoms to the EEG test. These results suggest that electrical CCCD is not a rare phenomenon and it is recommended that an electroencephalographer should be aware of the CCCD phenomenon, as one of the pitfalls in EEG, which may be presented as focal slow waves generally suggestive of supratentorial dysfunction.