http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
A Tunable Combline Bandpass Filter Loaded With Series Resonator
Xu-Guang Wang,Young-Ho Cho,Sang-Won Yun IEEE 2012 IEEE transactions on microwave theory and techniqu Vol.60 No.6
<P>This paper proposes a varactor-tuned microstrip combline bandpass filter (BPF) that is loaded with lumped series resonators instead of the short-circuited end of combline. This configuration has the advantage of enhancing the tunability of the suggested BPF by varactor diodes in series resonators, which leads to a wide tuning range even with a small capacitance ratio (<I>C</I><SUB>ratio</SUB>) of the varactor. Therefore, a low controlled bias voltage varactor-tuned BPF can be achieved. In addition, due to the controllable slope parameter of the proposed resonator, the coupling between resonators can be controlled. As a result, the proposed tunable BPF can keep nearly constant bandwidth over the wide tuning range. The insertion loss resulting from the varactors is compensated using an active capacitance circuit with negative resistance. Theoretical analysis and design approach are described. Experimental results of a demonstrative BPF show a 500-MHz tuning range (1.7-2.2 GHz) with <I>C</I><SUB>ratio</SUB> of only 2.6 (1-5-V bias voltage) while maintaining nearly constant absolute bandwidth and low insertion loss. The measured performance of the fabricated filter shows good agreement with the simulated one.</P>
Amperometric Determination of Nitrite at Poly(Methylene Blue)-Modified Glassy Carbon Electrode
Guang-Ri Xu,Guifang Xu,Ming-Lu Xu,Zhengqing Zhang,Yuan Tian,최한님,이원용 대한화학회 2012 Bulletin of the Korean Chemical Society Vol.33 No.2
Electrochemical characteristics of nitrite ion were investigated at a poly(methylene blue)-modified glassy carbon electrode by cyclic voltammetry and differential pulse voltammetry. The poly(methylene blue)-modified glassy carbon electrode exhibited enhanced anodic signals for nitrite. The effects of key parameters on the detection of nitrite were evaluated at the modified electrode, such as pH, accumulation time, and scan rate. Under optimum condition, the chemically modified electrode can detect nitrite in the concentration range 2.0 × 10−6 to 5.0 × 10−4 M with the detection limit of 2.0 × 10−6 M and a correlation coefficient of 0.999. The detection of nitrite using the chemically modified electrode was not affected by common ions such as Na+, K+,Ca2+, Cl−, HPO42− and H2PO4−. The modified electrode showed good stability and reproducibility. The practical application of the present method was successfully applied to the determination of nitrite ion in cabbage samples.
젖버섯아재비 자실체로부터 분리한 Azulene계 화합물이 Interferon-γ생성에 미치는 영향
( Guang Hua Xu ),김재화 ( Jae Wha Kim ),( Gao Li ),유익동 ( Ick Dong Yoo ) 대한화장품학회 2010 대한화장품학회지 Vol.36 No.2
버섯유래 생리활성물질을 탐색하고자, 젖버섯아재비 자실체로부터 각종 컬럼크로마토그래피 및 HPLC 등 기법에 의하여 4종의 azulene계 화합물을 순수히 분리정제 하였다. 분리된 화합물은 각종 물리화학적 특성 및 분광학적 분석자료에 의하여 1-formyl-4-methyl-7-isopropyl azulene (1), lactaroviolin (2), 4-methyl-7-isopropyl-azulene-1-carboxylic acid (3) 및 1-formyl-4-methyl-7-(1-hydroxy-1-methylethyl) azulene (4)로 동정되었다. 이들 화합물의 인터페론 감마생성에 미치는 영향을 조사하였다. 화합물 1과 4는 자연살해세포주(NK92 cell)에서 인터페론 감마 생성을 농도 의존적으로 억제하였으며, 400 μM농도에서 각각 101.3 %와 92.7 %, 100 μM농도에서 각각 11.9 %와 24.1 %의 높은 저해활성을 보였으며, 화합물 2와 3은 400 μM농도에서 45.9 %와 18.0 %의 다소 낮은 저해활성을 나타내었다. Investigation of secondary bioactive metabolites from the fruiting bodies of Lactarius hatsudake led to the isolation of four azulene derivatives by means of repeated column chromatography and preparative HPLC, and they were identified as 1-formyl-4-methyl-7-isopropyl azulene (1), lactaroviolin (2), 4-methyl-7-isopropyl-azulene- 1-carboxylic acid (3), and 1-formyl-4-methyl-7-(1-hydroxy-1-methylethyl) azulene (4) by their physico-chemical properties and spectroscopic analysis. The isolated compounds were evaluated for the effects on modulation of cytokines in natural killer cell line (NK92 cells). Compounds 1 and 4 strongly inhibited IFN-γ production in a dose-dependent manner, corresponding to 101.3 % and 92.7 % inhibition at 400 μM, and 11.9 % and 24.1 % at 100 μM, respectively, whereas compounds 2 and 3 showed weak inhibitory effect on INF-γ production, corresponding to 45.9 % and 18.0 % inhibition at 400 μM.
Surgical treatment for hepatocellular carcinoma with bile duct invasion
Xu-guang Hu,Wei Mao,Sung Yeon Hong,Bong-Wan Kim,Wei-guang Xu,Hee-Jung Wang 대한외과학회 2016 Annals of Surgical Treatment and Research(ASRT) Vol.90 No.3
Purpose: There is still some debate on surgical procedures for hepatocellular carcinoma (HCC) patients with bile duct tumor thrombi (BDTT, Ueda type 3 or 4). What is adequate extent of liver resection for curative treatment? Is extrahepatic bile duct resection mandatory for cure? The aim of this study is to answer these questions. Methods: Between February 1994 and December 2012, 877 consecutive HCC patients underwent hepatic resection at Ajou University Hospital. Thirty HCC patients (3.4%) with BDTT (Ueda type 3 or 4) were retrospective reviewed in this study. Results: In total, 20 patients enrolled in this study were divided into 2 groups: patients who underwent hemihepatectomy with extrahepatic bile duct resection (group 1, n = 10) and with only removal of BDTT (group 2, n = 10). The 1-, 3- and 5-year overall survival rates were 75.0%, 50.0%, and 27.8%, respectively. The 1-, 3-, and 5-year survival rates of group 1 were 100.0%, 80.0%, and 45.7%, and those of group 2 were 50.0%, 20.0%, and 10.0%, respectively (P = 0.014). The 1-, 3-, and 5-year recurrences free survival rates of group 1 were 90.0%, 70.0%, and 42.0%, and those of group 2 were 36.0%, 36.0%, and 0%, respectively (P = 0.014). Thrombectomy and infiltrative growth type (Ig) were found as independent prognostic factors for recurrence free survival by multivariate analysis. Thrombectomy, Ig, and high indocyanine green retention rate at 15 minutes were found as independent prognostic factors for overall survival by multivariate analysis. Conclusion: We suggest that the appropriate surgical procedure for icteric HCC patients should be comprised of ipsilateral hemihepatectomy with caudate lobectomy and extrahepatic bile duct resection.
Xu-Guang Hu,Xue-Yin Shen,Jin-Niang Nan,In-Gyu Kim,Joon-Kee Yoon,Sung-Yeon Hong,Mi-Na Kim,Bong-Wan Kim,Hee-Jung Wang 대한외과학회 2020 Annals of Surgical Treatment and Research(ASRT) Vol.99 No.1
Purpose: Hepatocellular carcinoma (HCC) patients with major portal vein tumor thrombosis (mPVTT) complications were generally characterized by extremely poor prognoses. The aim of this study was to explore the role of 18F-fluorodeoxyglucose (18F-FDG) PET/CT imaging in predicting HCC complicated by mPVTT. Methods: Five hundred one HCC patients received surgery in our hospital during November 2008 to December 2014, among which 32 patients (6.4%) were diagnosed as HCC complicated by mPVTT. Six cases were excluded for reasons of complex medical conditions, including 2 cases of salvage liver transplantation, 2 cases of re-resection, 1 case of mPVTT combined with inferior vina cava tumor thrombosis, and 1 case of residual portal vein tumor thrombosis. Ultimately, 26 cases were enrolled in this study. The maximal tumor standardized uptake value (SUVmax) was identified as a predictive factor and detected. The univariate and multivariate regression analyses were performed to identify the prognostic factors for recurrence-free survival (RFS) and overall survival (OS) of HCC patients complicated by mPVTT. Results: Our results showed that the median OS was 16 months. The 1-, 3-, and 5-year cumulative OS was 55.6%, 31.7%, and 31.7%, respectively. The multivariate regression analysis revealed that SUVmax ≥ 4.65 was the only independent risk factor for RFS and OS. Conclusion: SUVmax was an independent predictor for RFS and OS of patients suffering from both HCC and mPVTT. L ow SUVmax could serve as an effective factor for selecting candidates with low recurrence risks and for helping with improving patient survival after surgical resection.
Guang-Hua Xu,김영희,추수진,유익동,In-Ja Ryoo 대한약학회 2009 Archives of Pharmacal Research Vol.32 No.2
Bioassay-guided fractionation of the MeOH extract of Thuja orientalis fruits using a DPPH (2,2-diphenyl- 1-picrylhydrazyl) assay led to the isolation of 9 flavonoids: cupressuflavone (1), amentoflavone (2), robustaflavone (3), afzelin (4), (+)-catechin (5), quercitrin (6), hypolaetin 7-O-β-xylopyranoside (7), isoquercitrin (8) and myricitrin (9). Their chemical structures were determined by spectroscopic analyses. The free radical scavenging and human neutrophil elastase (HNE) inhibitory activities were evaluated for the isolated compounds. By DPPH scavenging assay, compounds 5, 6, 7, 8 and 9 showed anti-oxidant activities with IC50 values of 28.66, 31.19, 18.30, 26.63 and 15.10 μM, respectively. By ABTS [2,2'-azinobis(3- ethylbenzothiazoline-6-sulfonic acid) diammonium salt] scavenging assay, these compounds also exhibited potent anti-oxidant activities with IC50 values of 6.77, 13.96, 6.97, 22.79 and 9.96 μM, respectively. Of note, compounds 1, 2 and 3 showed significant HNE inhibitory activities with IC50 values of 8.09, 1.27 and 1.33 μM, respectively.