Rapid Increase in Marrow Fat Content and Decrease in Marrow Perfusion in Lumbar Vertebra Following Bilateral Oophorectomy: An MR Imaging-Based Prospective Longitudinal Study

Yi-Xiáng J Wáng,James F Griffith,Min Deng,David KW Yeung,Jing Yuan 대한영상의학회 2015 Korean Journal of Radiology Vol.16 No.1

Bilateral oophorectomy leads to reduced bone mineral density (BMD), and reduced BMD is associated with increased marrow fat and reduced marrow perfusion. Purpose of this study was to investigate how soon these changes occur following surgical oophorectomy. Six patients who underwent hysterectomy and bilateral salpingo-oophorectomy were studied. At baseline, mean patient age was 49.5 years (range: 45–54 years). Third lumbar vertebral body BMD measurement using quantitative CT, marrow fat fraction (FF) using MR spectroscopy and marrow perfusion using dynamic contrast enhanced MRI were conducted immediately prior to surgery and at 3, 9, and 21 months after surgery. Reduced BMD, increased marrow FF, and reduced marrow perfusion occurred synchronously post-oophorectomy. There was a sharp decrease of 12.5 ± 7.2% in BMD (n = 6), a sharp increase of 92.2 ± 46.3% (n = 6) in FF, a sharp decrease of 23.6 ± 3.9% in maximum contrast enhancement (n = 5), and of 45.4 ± 7.7% for enhancement slope (n = 5) during the initial 3 months post surgery. BMD and marrow perfusion continued to decrease, and marrow FF continued to increase at a slower rate during the following 18 months. Friedman test showed a significant trend for these changes (p < 0.05). Bilateral oophorectomy leads to a rapid decrease in lumbar BMD, an increase in marrow fat content, and a decrease in marrow blood perfusion.

Acetylcholinesterase Inhibitive Activity-Guided Isolation of Two New Alkaloids from Seeds of Peganum Nigellastrum Bunge by an In Vitro TLC- Bioautographic Assay

Xi-yuan Zheng,Chang-hong Wang,Zi-jia Zhang,Gui-xin Chou,Tao Wu,Xue-mei Cheng,Zheng-tao Wang 대한약학회 2009 Archives of Pharmacal Research Vol.32 No.9

Acetylcholinesterase inhibitors (AChEIs) currently form the basis of the newest drugs available for the treatment of Alzheimer's disease. For the aim of screening effective AChEIs, the methanol extracts of the seeds of genus Peganum were found to show significant inhibitory activity of acetylcholinesterase enzyme (AChE) using an in vitro TLC-bioautographic assay. In further studies to seed of P. nigellastrum Bunge, activity-guided fractionation led to the isolation of two new alkaloids nigellastrine Ⅰ (9) and nigellastrine Ⅱ (10), and along with eight known alkaloids, vasicinone (1), vasicine (2), harmine (3), deoxyvasicinone (4), deoxyvasicine (5), harmaline (6), harmol (7), harman (8), in which harmol and harman were first isolated from species P. nigellastrum Bunge. As active constituents, all compounds showed good inhibitory activities against AChE. The results of in vitro semi-quality TLC-bioautographic assay showed that harmine, harmaline and harmol displayed a similar AChE inhibitive activities comparing to galanthamine. These results indicated that these alkaloids in P. nigellastrum Bunge could be a potent class of AChEIs.

The Antecedents of Market Performance in China

Xi Na Yuan,이형석,김상용 한국경영학회 2009 한국경영학회 통합학술발표논문집 Vol.2009 No.08

국제학술 심포지움 쌀 박람회 / 특별강연 : 중국의 쌀 생산 , 유통 및 이용현황

(Xi Yuan Liao) 한국식품저장유통학회 ( 구 한국농산물저장유통학회 ) 2002 국제학술심포지움 쌀박람회 Vol.- No.-

Novel and Effective Almagate Enema for Hemorrhagic Chronic Radiation Proctitis and Risk Factors for Fistula Development

Yuan, Zi-Xu,Ma, Teng-Hui,Zhong, Qing-Hua,Wang, Huai-Ming,Yu, Xi-Hu,Qin, Qi-Yuan,Chu, Li-Li,Wang, Lei,Wang, Jian-Ping Asian Pacific Journal of Cancer Prevention 2016 Asian Pacific journal of cancer prevention Vol.17 No.2

Radiation proctitis is a common complication after radiotherapy for pelvic malignant tumors. This study was conducted to assess the efficacy of novel almagate enemas in hemorrhagic chronic radiation proctitis (CRP) and evaluate risk factors related to rectal deep ulcer or fistula secondary to CRP. All patients underwent a colonoscopy to confirm the diagnosis of CRP and symptoms were graded. Typical endoscopic and pathological images, risk factors, and quality of life were also recorded. A total of 59 patients were enrolled. Gynecological cancers composed 93.1% of the primary malignancies. Complete or obvious reduction of bleeding was observed in 90% (53/59) patients after almagate enema. The mean score of bleeding improved from 2.17 to 0.83 (P<0.001) after the enemas. The mean response time was 12 days. No adverse effects were found. Moreover, long-term successful rate in controlling bleeding was 69% and the quality of life was dramatically improved (P=0.001). The efficacy was equivalent to rectal sucralfate, but the almagate with its antacid properties acted more rapidly than sucralfate. Furthermore, we firstly found that moderate to severe anemia was the risk factor of CRP patients who developed rectal deep ulcer or fistulas (P= 0.015). We also found abnormal hyaline-like thick wall vessels, which revealed endarteritis obliterans and the fibrosis underlying this disease. These findings indicate that almagate enema is a novel effective, rapid and well-tolerated method for hemorrhagic CRP. Moderate to severe anemia is a risk factor for deep ulceration or fistula.

Copper Particle Effect on the Breakdown Strength of Insulating Oil at Combined AC and DC Voltage

You-Yuan Wang,Yuan-Long Li,Chao Wei,Jing Zhang,Xi Li 대한전기학회 2017 Journal of Electrical Engineering & Technology Vol.12 No.2

Converter transformer is the key equipment of high voltage direct current transmission system. The solid suspending particles originating from the process of installation and operation of converter transformer have significant influence on the insulation performance of transformer oil, especially in presence of DC component in applied voltage. Under high electric field, the particles easily lead to partial discharge and breakdown of insulating oil. This paper investigated copper particle effect on the breakdown voltage of transformer oil at combined AC and DC voltage. A simulation model with single copper particle was established to interpret the particle effect on the breakdown strength of insulating oil. The experimental and simulation results showed that the particles distort the electric field. The breakdown voltage of insulating oil contaminated with copper particle decreases with the increase of particle number, and the breakdown voltage and the logarithm of particle number approximately satisfy the linear relationship. With the increase of the DC component in applied voltage, the breakdown voltage of contaminated insulating oil decreases. The simulation results show that the particle collides with the electrode more frequently with more DC component contained in the applied voltage, which will trigger more discharge and decrease the breakdown voltage of insulating oil.

밝기 비트맵과 색도 일관성을 이용한 무 잔상 High Dynamic Range 영상 생성

위엔시(Xi Yuan),하호건(Ho-Gun Ha),이철희(Cheol-Hee Lee),하영호(Yeong-Ho Ha) 대한전자공학회 2015 전자공학회논문지 Vol.52 No.1

HDR(high dynamic range) 영상 생성은 실세계의 고명암비 영상을 재현하는 방법이다. Exposure fusion은 여러 HDR 영상 생성방법 중 한 가지로 true-HDR 영상을 생성하지 않고, 바로 pseudo-HDR 영상을 생성하는 방법이다. 그러나 노출이 다른 여러 입력영상들 중에서 이동하는 물체가 존재하면 잔상 효과가 발생하여 pseudo-HDR 영상의 화질 열화를 가져온다. 이러한 단점을 해결하기 위해 본 논문에서는 시간 영역에서 일치성 평가를 통한 무 잔상 exposure fusion을 제안하였다. 먼저 다중 역치 및 밝기를 이용한 비트맵과 색도 일관성 맵을 이용하여 각 입력 영상들간의 일치성을 평가하였고, 이를 시간 영역 가중치 맵으로 나타내었다. 그리고 기존 exposure fusion에서의 공간 영역 가중치 맵과 결합하여 최종 가중치 맵을 생성하였다. 마지막으로 각각 입력 영상에 최종 가중치 맵을 적용한 후, 합성하여 잔상이 제거된 pseudo-HDR 영상을 생성하였다. 실험을 통해 제안된 방법의 pseudo-HDR이 기존의 방법보다 잔상이 더 많이 제거되어 화질이 개선됨을 확인하였고, 객관적인 평가 방법인 기준 영상 대비 오차도 더 적게 나타남을 확인하였다. HDR(High dynamic range) imaging is a technique to represent a dynamic range of real world. Exposure fusion is a method to obtain a pseudo-HDR image and it directly fuses multi-exposure images instead of generating the true-HDR image. However, it results ghost artifacts while fusing the multi-exposure images with moving objects. To solve this drawback, temporal consistency assessment is proposed to remove moving objects. Firstly, multi-level threshold bitmap and brightness bitmap are proposed. In addition, hue-angle constancy map between multi-exposure images is proposed for compensating a bitmap. Then, two bitmaps are combined as a temporal weight map. Spatial domain image quality assessment is used to generate a spatial weight map. Finally, two weight maps are applied at each multi-exposure image and combined to get the pseudo-HDR image. In experiments, the proposed method reduces ghost artifacts more than previous methods. The quantitative ghost-free evaluation of the proposed method is also less than others.

Experimental Study and Analysis of Insulator Breakdown Characteristics with Short-tail Lightning Impulse

Zhao, Yuan,Li, Yu,Deng, Chun,Yuan, Yi-Chao,He, Jin-Liang,Wang, Xi The Korean Institute of Electrical Engineers 2014 The Journal of International Council on Electrical Vol.4 No.3

The voltage waveform on the insulator by a direct lightning stroke is a short-tail lightning impulse. Experimental study and analysis of insulator breakdown characteristics under short-tail lightning impulses are given in this paper with the contrast of standard lightning impulse. The impacts of crossarm and transmission lines are also considered. The experimental results indicate that the insulator 50% breakdown voltage under short-tail impulse is significantly higher than that of standard wave with both positive and negative polarities, about 25~30%. The 50% breakdown voltage of insulator with negative-polarity short-tail impulse is about 5% higher than with positive-polarity one. The insulator voltage-time characteristics are also given with short-tail and standard lightning impulses.

Copper Particle Effect on the Breakdown Strength of Insulating Oil at Combined AC and DC Voltage

Wang, You-Yuan,Li, Yuan-Long,Wei, Chao,Zhang, Jing,Li, Xi The Korean Institute of Electrical Engineers 2017 Journal of Electrical Engineering & Technology Vol.12 No.2

Converter transformer is the key equipment of high voltage direct current transmission system. The solid suspending particles originating from the process of installation and operation of converter transformer have significant influence on the insulation performance of transformer oil, especially in presence of DC component in applied voltage. Under high electric field, the particles easily lead to partial discharge and breakdown of insulating oil. This paper investigated copper particle effect on the breakdown voltage of transformer oil at combined AC and DC voltage. A simulation model with single copper particle was established to interpret the particle effect on the breakdown strength of insulating oil. The experimental and simulation results showed that the particles distort the electric field. The breakdown voltage of insulating oil contaminated with copper particle decreases with the increase of particle number, and the breakdown voltage and the logarithm of particle number approximately satisfy the linear relationship. With the increase of the DC component in applied voltage, the breakdown voltage of contaminated insulating oil decreases. The simulation results show that the particle collides with the electrode more frequently with more DC component contained in the applied voltage, which will trigger more discharge and decrease the breakdown voltage of insulating oil.

Experimental Study on Mechanical Properties and Toughness of Q460C High-strength Steel and Its Butt Welded Joint at Low Temperature

Xi-yue Liu,Yuan-Qing Wang,Liang Zong,Yun Lin,Yong-Jiu Shi 한국강구조학회 2014 International Journal of Steel Structures Vol.14 No.3

Compared with the conventional steel structure, the high-strength steel structures are at more risk of brittle fracture, especiallyin cold regions. In the present study, a series of tests (such as uniaxial tensile test, Charpy impact test and three-point bendingtest) were carried out at low temperature to investigate the mechanical properties and toughness of Q460C steel and its buttwelded joint, fracture micro-mechanisms were analyzed as well. The ductility indices and the toughness indices all decreasewith temperature decreases, the heat affected zone (HAZ) in welded joint is more critical to fracture than the base material. The fracture toughness of high-strength steel Q460C is relatively lower than the other three conventional steels (i.e. Q235, Q345and Q390). In this study, rich experimental data were collected so as to provide reference for the fracture resistant design ofhigh-strength steel structures in cold regions.