A multi-detection fluorescence dye with 5-ALA and ICG Using modified Light Emitting Diodes

윤기철,김은지,김광기,이승훈,유현 한국광학회 2019 Current Optics and Photonics Vol.3 No.3

Extensive tumor resection accompanied by radiotherapy and chemotherapy is the standard of care for malignant gliomas. However, there is a significant obstacle to the complete resection of the tumor due to the difficulty of distinguishing tumor and normal brain tissue with a conventional surgical microscope. Recently, multiple studies have shown the possibility of fluorescence-guided surgery in malignant gliomas. The most used fluorescence dyes for brain tumor surgery are 5-aminolevulinic acid (5-ALA) and indocyanine green (ICG). In this paper, a new fluorescence guided operation system, which can detect both 5-ALA and ICG fluorescent images simultaneously, is presented. This operation system consists of light emitting diodes (LEDs) which emits 410 nm and 740 nm wavelengths. We have performed experiments on rats in order to verify the operation of the newly developed operation system. Oral administration and imaging were performed to observe the fluorescence of 5-ALA and ICG fluorescence in rats. When LEDs at wavelengths of 410 nm and 740 nm were irradiated on rats, 628 nm wavelength with a violet fluorescence color and 825 nm wavelength with a red fluorescence color were expressed in 5-ALA and ICG fluorescent material, respectively, thus we were able to distinguish the tumor tissues easily. Previously, due to the poor resolution of the conventional surgical microscope and the fact that the color of the vein is similar to that of the tumor, the tumor resection margin was not easy to observe, thus increasing the likelihood for cancer recurrence. However, when the tumor is observed through the fluorescence guided operation system, it is possible to easily distinguish the color with the naked eye and it can be completely removed. Therefore, it is expected that surgical removal of cancerous tumors will be possible and surgical applications and surgical microscopes for cancer tumor removal surgery will be promising in the future.

고조파가 억제된 5.8 GHz 협대역 대역통과 여파기

윤기철,이종철 한국통신학회 2008 韓國通信學會論文誌 Vol.33 No.2

폴리퀴놀린의 합성과 방사에 관한 연구(IV)-퀴놀린 단위가 도입된 방향족 폴리이미드의 합성과 그 특성(II)-

윤기철,임재봉 한국섬유공학회 1993 한국섬유공학회지 Vol.30 No.6

Diaminoquinoline monomers, which were QDA(P), QDA(M), and QDA(BP), were synthesized via the Friedlander quinoline synthesis reaction and identified with IR spectrometer. and 1H-NMR spectrometer. Diaminoquinoline monomers were reacted with pyromellitic dianhydride and benzophenone tetracarboxylic dianhydride to obtain the polyquinoline amis acids. The polyquinoline mimic acids wert converted to poly(quinoline imide)s by thermal imidization methods. FT-IR spectra and 1H-NMR spectra of polymers exactly showed that the polyamic acids were successfully converted to polyimides. The analyses of the thermal and mechanical properties of poly(quinoline imide)s showed that poly(quinoline imide)s had good properties corresponding to those of polyimides.

전송선로의 임피던스 부정합을 이용한 협대역 개방형 소형 스터브 대역통과 여파기

윤기철,오승연,오경민,이현욱,홍태의,이종철 한국ITS학회 2008 한국ITS학회논문지 Vol.7 No.6

본 논문에서는 ag/2 개방형 협대역 소형 스터브 대역통과 여파기를 새롭게 제안한다. 이 여파기를 연구하는 목적은 전송선로에서 발생하는 2차 고조파를 이용하여 여파기의 가로 측 길이를 줄이는 것이고, 또한 동시에 공진부와 전송선로에서 발생하는 기본파를 이용하여 전력을 전달하기 위하여 임피던스 부정합 기법을 이용하는 것이다. 그러므로 여파기의 가로 측 길이는 기존에 비해 1/2로 축소되었다는 것을 확인할 수 있었다. 설계된 여파기의 대역폭은 10 % 이고, 중심 주파수는 5.8 GHz이며, 측정 결과의 삽입손실 및 반사손실은 각각 1.58 dB, 9.86 dB의 결과 값을 얻었고 크기는 10.34*18.56 mm2 이다. In this paper, the narrow band-pass filter with compact-size using the ag/2 open stubs is proposed. The filter size is reduced by realization of transmission line at second harmonics and at the same time the power can be transferred to the output by using the fundamental wave generated in the resonator and the transmission line in which the impedance mismatch technique is adopted. Thus, the proposed filter can be reduced to half-length of horizontal transmission line than the conventional one. The experimental results show that insertion loss is 1.58 dB and return loss is 9.86 dB, and the fractional bandwidth is 10 % at the center frequency of 5.8 GHz. The filter size is 10.34*18.56 mm2.

메타 인공 물질을 이용한 새로운 Split-Ring 공진기 및 대역통과 필터

윤기철,이종철 한국ITS학회 2010 한국ITS학회논문지 Vol.9 No.4

본 논문에서는 메타 인공 물질을 이용한 스플릿 링 공진기를 새롭게 제안하여 2단 필터를 설계 하였다. 제안된 필터는 새로운 공진기의 크기를 자유롭게 조절할 수가 있고, 탭-선로의 위치를 이용하여 대역폭을 쉽게 조절할 수가 있다. 제안된 공진기 및 필터는 군사용 위성통신 대역인 I-밴드의 10 GHz 중심 주파수에서, 공진기의 Qe값은 184이며, 필터의 대역폭은 10 %이고, 삽입손실 및 반사손실은 각각 1.43 dB 와 16.8 dB의 값을 얻었다. In this paper, a new split ring resonator using left-handed meta-material adapted in a bandpass filter with 2-stages is suggested. In this proposed bandpass filter, the size of the novel resonator can be easily controlled. Also, the bandwidth can be adjusted with the position of the tapped-line. The proposed resonator and filter has the center frequency of 10 GHz for I-band in military-satellite communication system with the Qe value of 184. The experimental results of the filter show that the insertion and return losses are 1.43 dB and 16.8 dB with bandwidth of 10 %, respectively.

Pseudo-Combline을 이용한 이중대역 협대역 대역통과 여파기

윤기철,이현욱,이맹,이재영,이종철 한국ITS학회 2011 한국ITS학회논문지 Vol.10 No.6

본 논문은 이중대역 Pseudo-combline 협대역 대역통과 여파기를 제안한다. 제안한 이중대역 대역통과 여파기의 특징은 개방형 공진 스터브를 사용하고 있으며 ITS와 X-밴드 위성 시스템에 적용이 가능하다. 이중대역 대역통과 여파기는 첫 번째 운용 주파수 대역의 중심 주파수 5.8 GHz 그리고 대역폭 3.6 %에서 삽입 및 반사 손실이 각각 1.72 dB 및 15.5 dB이다. 또한 두 번째 운용 주파수 대역의 중심 주파수 8.5 GHz 그리고 대역폭 3%에서 삽입 및 반사 손실은 각각 1.92 dB 및 16.3 dB 이다. In this paper, a dual-band pseudo-combline narrow bandpass filter is proposed. The proposed bandpass filter adopts the open resonant stubs and the proposed bandpass filter can be used for ITS(Intelligent Transport System) and X-band satellite systems application. The proposed bandpass filter has the insertion and return losses of 1.72 dB and 15.5 dB at the bandwidth of 3.6 % and center frequency of 5.8 GHz, respectively. Also, the second operating frequency band for insertion and return losses are 1.92 dB and 16.3 dB at the bandwidth of 3% and center frequency of 8.5 GHz, respectively.

Compact-size Narrow Bandwidth Duplexedr with Left-handed Metamaterial

윤기철,김태영,Yang Wang,정해수,김정태,이종철 한국ITS학회 2015 한국ITS학회 학술대회 Vol.2015 No.10

MNG 메타 인공 물질을 이용한 T-SRR 및 저손실 대역통과 필터의 설계

윤기철,김성철,Yoon, Ki-Cheol,Kim, Seong-Cheol 한국정보통신학회 2013 한국정보통신학회논문지 Vol.17 No.11

본 논문은 MNG (mu-Negative) 메타 인공 물질을 이용한 T-SRR (Triple Split Ring Resonator)을 제안하여 3단의 저손실 대역통과 필터를 응용 설계를 하였다. 제안된 대역통과 필터는 낮은 유전율을 가진 기판 위에 T-SRR의 크기를 자유롭게 조절할 수 있고 ${\lambda}/4$ 전송선로를 적용하여 저손실 대역통과필터로 응용설계함. 또한 군사용 위성통신대역의 I-밴드 10 GHz 중심 주파수에서, 필터 내의 T-SRR의 QL값은 184이며, 필터의 대역폭은 10 % 일 때, 삽입손실 및 반사손실은 각각 1.44 dB 와 17.3 dB의 값을 얻었다. 향후 IPD(Integrated Passive Device)등으로 재설계가 가능할 것임. In this paper, the T-SRR (Triple Split Ring Resonator) using MNG (mu-Negative) meta-material adapted in a low-loss bandpass filter with 3-stages is suggested. The size of the T-SRR in the proposed bandpass filter with low dielectric constant PCB can be easily controlled. And the ${\lambda}/4$ transmission line theory is applied. The proposed T-SRR and filter have the center frequency of 10 GHz with QL value of 184 for military-satellite communication system in I band. The experimental results of the filter show that the insertion and return losses are 1.44 dB and 17.3 dB with bandwidth of 10 %, respectively. The proposed filter will be redesigned by IPD material etc. should be placed here. These instructions give you guidelines for preparing papers for JICCE.

Left-handed Metamaterial을 이용한 IDC 형태의 소형 UWB Coplanar Waveguide

윤기철,안승영,이종철 한국ITS학회 2016 한국ITS학회 학술대회 Vol.2016 No.04

황산카드뮴독성의 산화적 손상에 대한 부들 추출물의 항산화 효과

윤기철,손영우 한국환경보건학회 2019 한국환경보건학회지 Vol.45 No.1

Objectives: This study was carried out to analyze the cytotoxicity of cadmium sulfate (CdSO 4 ) and the antioxidative effect of Typha orientalis L. (TO) extract on the oxidative stress induced by cytotoxicity of CdSO 4 in the cultured NIH3T3 fibroblasts. Methods: For this study, the cell viability and the antioxidative effects such as the inhibitory activity of lipid peroxidation (LP) and superoxide dismutase (SOD)-like activity and xanthine oxidase (XO)-inhibitory activity were assessed. Results: The cadmium sulfate significantly decreased cell viability in dose-dependently, and XTT 50 value was measured at 47.4 µM of CdSO 4 . The cytotoxicity of CdSO 4 was determined as highly toxic by Borenfreund and Puerner's toxic criteria. The butylated hydroxytoluene (BHT) as antioxidant significantly increased cell viability injured by CdSO 4 -induced cytotoxicity in these cultures. In the protective effect of TO extract on CdSO 4 -induced cytotoxicity, TO extract remarkably increased the inhibitory ability of LP and XO as well as SOD-like ability. Conclusions: From the above results, it is suggested that the oxidative stress is involved in the cytotoxicity of CdSO 4 , and TO extract effectively protected CdSO 4 -induced cytotoxicity by antioxidative effects. The natural component like TO extract may be a putative therapeutic agent for treatment of the toxicity induced by heavy metallic compound like CdSO 4 correlated with the oxidative stress.