A Differential Current-to-Time Converter for ISFET Biosensors

Chang-Su Won,Won-Sup Chung 대한전자공학회 2009 ITC-CSCC :International Technical Conference on Ci Vol.2009 No.7

The differential current-to-time converter consists of a ramp voltage generator, an ISFET biosensor, a reference FET (REFET), two gain-adjustable current amplifiers, two current-tunable Schmitt triggers, and two logic gates. The design principle is to apply a ramp voltage to each input of the two current-tunable Schmitt triggers whose threshold voltages are proportional to the drain current values of the ISFET biosensors. A proposed circuit converts a current change in the ISFET biosensor into its equivalent pulse width change. A prototype circuit built using discrete components exhibit a conversion sensitivity amounting to 645.54 ㎲/pH s μ over pH variation range of 1-14 and a linearity error less than 0.001 %.

Carburization of Iron Using CO-H₂ Gas Mixture

Hwang, Ho-Sun,Chung, Uoo-Chang,Chung, Won-Sub,Cho, Young-Rae,Jung, Byong-Ho,Martin G.P. 대한금속재료학회 2004 METALS AND MATERIALS International Vol.10 No.1

Iron carbides formed on the surface of iron and iron oxide samples at 640℃ in a gas mixture of CO-H₂ were characterized by scanning electron microscopy (SEM), MGssbauer spectroscopy, X-ray diffraction patterns (XRD), and by measuring mass change. The Fe₃C amount of the samples has been quantitatively evaluated by the weight change during carburization. While Fe₂O₃ powder was mostly completed to Fe₃C in the early stage, within 5 min after reduction reactions, the conversion of Fe powder sample to Fe₃C (iron carbide) was almost finished after 10 min. The carburization rate of a Fe sheet was very slow and intermediate products (Fe₂C, Fe₃C₂) were observed. This phenomenon is largely due to the difficulty of carbon diffusion into its dense surface. It was found that the carburization rate was affected by change of surface conditions and surface area by reduction, degradation, and cracks at high temperature. This study should help provide a fundamental understanding of carburization in the field of iron-making and suggest a direction for its further development.

<i>Pleurospermum kamtschaticum</i> Extract Induces Apoptosis <i>via</i> Mitochondrial Pathway and NAG-1 Expression in Colon Cancer Cells

KIM, Jin-Eun,CHUNG, Won-Yoon,CHUN, Kyung-Soo,LEE, Chang Ki,PARK, Hee-Juhn,KIM, Won-Bae,PARK, Kwang-Kyun Japan Society for Bioscience, Biotechnology, and A 2010 Bioscience, Biotechnology, and Biochemistry Vol.74 No.4

<P>To evaluate the anticarcinogenic activity of methanol extract of <I>Pleurospermum kamtschaticum</I> (PKE), we assessed its apoptosis-inducing capability in HT-29 colon carcinoma cells. PKE treatment for 2 h reduced cell viability in a dose-related manner, and induced apoptotic morphological changes. Flow cytometric analysis indicated that PKE treatment at 0.05 mg/ml induced early apoptosis in 66.2% of HT-29 cells. Additionally, Bcl-2 expression was substantially reduced in PKE-treated HT-29 cells, increasing the Bax/Bcl-2 ratio. The protein levels of procaspase-9 and procaspase-3 were decreased markedly, reflecting caspase-9 and caspase-3 activation, and resulting PARP cleavage was noted in the PKE-treated HT-29 cells. Furthermore, we detected increased NAG-1 expression in the PKE-treated HT-29 cells. In an <I>in vivo</I> study, intraperitoneal PKE administration suppressed the formation of tumor nodules in the lungs of mice. These results indicate that PKE can serve as a beneficial supplement in the treatment and the prevention of colon cancer.</P>

Endoscopy and Imaging Modalities/Basic Science of Gastrointestinal Disorders/Miscellaneous : Changing Pattern Of Digestive And Liver Disease In Korea, 1990-2006 Year; A Single Center Study

( Jung Hyun Kwon ),( Sang Woo Kim ),( In Sik Chung ),( Myung Gyu Choi ),( Kwan Woo Nam ),( Jung Pil Suh ),( Jae Hyuck Chang ),( Won Haing Hur ),( Yu Kyung Cho ),( Jae Myung Park ),( In Seok Lee ) 대한소화기학회 2007 SIDDS Vol.9 No.-

Background/Aims: Westernization in many Asian countries have changed lifestyles and diets, so once rare diseases have now become prevalent. The aim of this study is to investigate the changing pattern of digestive and liver disease in Korea, from 1990 to 2006. Methods: We extracted data specific gastrointestina (GI) disease based on the International Classification of Diseases code from the in-patients records at the Kangnam St. Mary`s Hospital in 1990, 1996 and 2006. This hospital is a tertiary-care hospital in Seoul, Korea, which has a capacity of 800 beds. Results: The admission rate for GI disease increased between 1990 and 2006. Overall in-patients were 1,623 persons in 1990, 2,368 persons in 1996 and 4,166 persons in 2006. The mean age of in-patients increased as time went by. A stomach cancer was the most common diagnosis during all periods, but its prevalence has decreased. Colon cancer ranked the 7th in 1990, but markedly increased and now ranks the second. The third was a hepatocellular carcinoma. The bile duct and gallbladder cancer, pancreas and esophageal cancer ranking followed with little interval change. In cases of cancer patients, a regular admission dramatically increased for chemotherapy. The number of patients admitted with pre-malignant neoplasm of stomach and colon increased remarkably with the development of endoscopy. The liver transplant, inflammatory bowel discase, and reflux esophagitis emerged form mid-1990s with greater frequencies, yet much below the levels found in the West. The admission rate for peptic ulcer, especially ulcer bleeding remained relatively stable, despite a decreased rate for ulcer perforation. Liver cirrhosis, hepatitis, cholelithiasis with cholecystitis-cholangitis, appendicitis, hemorrhoid and gastritis all decreased. Conclusions: The stomach cancer is the leading cause of admission, despite a recent decline. Colon cancer showed a marked rise. The liver transplant, inflammatory bowel disease and reflux esophagitis were new diagnosis with an increased tendency.

임플란트 식립후 발생한 동통성 지각이상의 미세외과적 처치와 경과

김명래(Myung Rae Kim),이원호(Won Ho Lee),최장우(Chang Woo Choi),정현주(/Hyun Ju Chung) 대한구강악안면외과학회 1998 대한구강악안면외과학회지 Vol.24 No.4

Purpose : This study is to examine the painful dysesthesia of lip & gingiva followed after implant surgeries and to evaluate the prognosis of microsurgical epineurotomy & tubulization with e-PTFE tubes. Method : Three patients who had been suffered from painful anesthesia and dysesthesia following dental implant surgeries were examined periodically and followed for over 1 year after epineurotomy and e-PTFE tubulization. Neurosensory dysfunctions were examined by Static Light Touch Threshold, Moving Direction Discrimination, Two Point Discrimination, Pin-Prick Nociception Visual Analog Scales and Tinel sign. The subjective symptoms were confirmed by SSEP and DITI prior to surgical exploration. Result : Two patients complained of continuous tearing and lancinating pain disclosed complete avulsion of IAN and degenerative changes with neuroma. One patient complained of mild painful dysesthesia revealed partial adhesion & fibrous epineural changes. Two patients whose IAN were explored after over 1 year resulted in only mild improvement in sensory recovery and moderate reduction of pain score. While the patient to whom decompression & epineural repair were given in 3 months after nerve injuries resulted in satisfactory improvement in sensory function and pain reduction. Conclusion : Painful dysesthesias occurred after implant placement were resulted from neurotmesis and disclosed degenerative neuropathy. Therefore, the micro-surgical explorations and repairs (epineurotomy, decompression neurolysis, and neurorrhaphy) can be recommended for known injuries as early as possible. For the delayed painful dysesthesia lasted over one year, however, epineurotomy & tubulization could be an option to improve the painful discomfort but not satisfactory.

EMI/EMC 실험을 위한 Four-wires을 이용한 안테나 설계

강성원,김준규,소준호,정용식,천창율,Gang, Sung-Won,Kim, Jun-Kyu,So, Jun-Ho,Chung, Young-Seek,Cheon, Chang-Yul 한국전자파학회 2007 한국전자파학회논문지 Vol.18 No.6

In this paper, a Four-wired antenna was designed and manufactured using Four-wires in order to perform EMI/EMC experiments. As compared with a TEM cell, the feature of the Four-wired antenna has simple installment with broadband balun, a Four-wired antenna, and loading resistances in an anechoic chamber. And the E-field polarization of antenna can be easily changed. Without the limitation of space, EMI/EMC experimental environment could be built within the anechoic chamber with the moderate cost. In S, C, and X-bands, the manufactured antenna was able to make an experiment on EMI/EMC with the DUT which has the quiet zone of the height, width, length equal to about 10 cm. 본 논문은 Four-wired 안테나를 이용하여 EMI/EMC 실험을 할 수 있는 안테나를 설계, 제작하였다. 일반 TEM-cell과 비교하여 이번 논문에서 설계, 제작하는 안테나의 특징은 무반향실에 broadband balun, Four-wired 안테나와 Loading resistances을 쉽게 설치하여, E-field polarization을 선택 할 수 있다는 점이다. 그리고 공간의 제약없이 기존의 무반향실을 이용하여 적은 비용으로 EMI/EMC 실험 환경을 구축할 수 있다. 제작된 안테나는 S, C 및 X-band에서 EMI/EMC 실험을 할 수 있는 가로, 세로, 높이 모두 약 10 cm 정도의 크기를 갖는 quiet zone을 얻을 수 있었다.

측면 방사선 촬영 자세의 표준화를 위한 정상 척추의 시상면 정렬의 분석

김민석(Min-Seok Kim),정석원(Seok-Won Chung),황창주(Changju Hwang),이춘기(Choon-Ki Lee),장봉순(Bong-Soon Chang) 대한정형외과학회 2005 대한정형외과학회지 Vol.40 No.7

목적: 양팔의 자세 변화에 따르는 척추의 시상면 정렬의 차이를 분석하고, 환자에게서 가장 기능적인 시상면 정렬을 재현 할 수 있는 측면 기립 방사선 촬영 자세를 제시하고자 하였다. 대상 및 방법: 정상 성인 남자 30명에 대해 제7 경추와 제1 천추의 피부 표면에 표식자를 부착시킨 후 전 척추측면 기립 방사선 촬영을 시행하였다. 팔을 내리고 서있는 자세(자세 A), 견관절을 각각 30°, 90° 굴곡한 자세(자세 B, C), 양팔을 끌어안은 자세(cross-arm position) (자세 D), 견관절을 90° 굴곡시킨 후 팔을 수평봉에 얹은 자세(자세 E)를 취하게 하여, 자세 변화에 따른 시상 수직축(sagittal vertical axis), 흉추 후만각, 요추 전만각, 천추 전경각의 차이에 대해 분석하였다. 결과: 자세 A에서 E의 평균 시상 수직축은 각각 +1.47±2.06 cm, -0.58±2.96 cm, -2.11±2.67 cm, +0.16±2.38 cm, -0.51±2.70 cm으로 일차원 분산분석(one-way ANOVA)을 시행한 결과 그룹간의 유의한 차이를 보였고(p<0.001), Duncan의 사후검증결과 자세 A와 D는 차이가 없는 것으로 판단되어 자세 D가 자세 A에 대해 가장 유사한 자세로 나타났다. 흉추 후만각, 요추 전만각, 천추 전경각은 자세간의 유의한 차이를 보이지 않았다. 결론: 양팔을 끌어안은 자세(crosss-arm position)는 평상시 서있는 자세와 가장 유사한 기능적인 시상면 정렬을 구현할 수 있는 자세로 생각된다. Purpose: To analyze the difference in sagittal balance based on different positions of both arms and to promote the proper lateral spine view which can reconstruct the most functional posture of sagittal balance. Materials and Methods: We applied X-rays to thirty healthy male adults with no spinal diseases after application of marks on the skin surface at the location of the C7 and S1 vertebrae with the following five postures, standing lateral position with both arms neutral (posture A) with both shoulders flexed thirty degrees and ninety degrees (postures B and C) with both arms crossed (posture D) with both shoulders flexed ninety degrees and with both arms on a parallel bar (posture E). We analyzed the differences of the sagittal vertical axis, thoracic kyphotic angle, lumbar lordotic angle, and sacral inclination angle after the postural changes. Results: The average sagittal vertical axis value from posture A to E was 1.47±2.06 cm, -0.58±2.96 cm, -2.11±2.67 cm, 0.16±2.38 cm, and -0.51±2.70 cm. We discovered that five postures were statistically different (one-way ANOVA, p<0.001) and that posture D was the closest to posture A (Duncan's multiple comparison test). However we did not observe any statistical differences among the thoracic kyphotic angle, the lumbar lordotic angle, and sacral inclination angle postures. Conclusion: We can reconstruct the functional sagittal alignment in the cross-arm position, which is the closest to the normal standing position.

신정부 과학기술정책 방향 모색

홍성주(Sung Joo Hong),이다은(Da Eun Lee),홍창의(Chang Ui Hong),강민지(Min Ji Kang),우청원(Chung Won Woo),강홍렬,전찬미 과학기술정책연구원 2017 정책연구 Vol.- No.-

With the presidential election in 2017 as a momentum, many people in science and engineering and social organizations gave various science and technology policy proposals. Most of them were reflected in each party’s election pledges. The media also covered lots of science and technology policy issues, which mainly included agendas reflecting the voices of the fields of R&D like research autonomy and people-oriented investment. This task aims to understand how the landscape of science and technology policies changed in an era of political change. To achieve this, we pursued to answer three research questions. First, how are we going to look at the vitalization of science and technology policy issues that occurred in the presidential election and its results? Second, what was it like in the past? Did the previous governments faithfully carry out their science and technology pledges in their science and technology policies? Third, what is the blind spot of policies that failed to attract attention or became a dilemma despite the change in science and technology policies? In order to answer these questions, the research team analyzed the way of establishing the window for science and technology policies during the presidential election in 2017, while also looked at the path taken for science and technology pledges to be implemented as policies during the past 15 years after the Rho Moo Hyun Government. The analysis results showed that we need to take largely four different approaches to science and technology issues. From the medium and long term perspective, it can be divided into issues that need access, issues that need enhancement, issues that need to gain political interests and issues that need to improve rationality. The research team’s results presented important perspective and methodology of looking at science and technology policy by not only being applied as a standard and means, but also provided a framework for devising various methods and means by policy issue. Hopefully, our researches are helpful in the planning and implementation of science and technology policy by the new government, which will be inaugurated in May 2017.

Using Real-Time Electron Microscopy To Explore the Effects of Transition-Metal Composition on the Local Thermal Stability in Charged Li_<i>x</i>Ni_<i>y</i>Mn_<i>z</i>Co_{1–<i>y</i>–<i>z</i>}O<sub>2</sub

Hwang, Sooyeon,Kim, Seung Min,Bak, Seong-Min,Kim, Se Young,Cho, Byung-Won,Chung, Kyung Yoon,Lee, Jeong Yong,Stach, Eric A.,Chang, Wonyoung American Chemical Society 2015 Chemistry of materials Vol.27 No.11

<P>In this work, we use in situ transmission electron microscopy (TEM) to investigate the thermal decomposition that occurs at the surface of charged LixNiyMnzCo1-y-zO2 (NMC) cathode materials of different composition (with y, z = 0.8, 0.1, and 0.6, 0.2, and 0.4,and 0.3), after they have been charged to their practical upper limit voltage (4.3 V). By heating these materials inside the TEM, we are able to directly characterize near surface changes in both their electronic structure (using electron energy loss spectroscopy) and crystal structure and morphology (using electron diffraction and bright-field imaging). The most Ni-rich material (y, z = 0.8, 0.1) is found to be thermally unstable at significantly lower temperatures than the other compositionsthis is manifested by changes in both the electronic structure and the onset of phase transitions at temperatures as low as 100 degrees C. Electron energy loss spectroscopy indicates that (i) the thermally induced reduction of Ni ions drives these changes, and (ii) this is exacerbated by the presence of an additional redox reaction that occurs at 4.2 V in the y, z = 0.8, 0.1 material. Exploration of individual particles shows that there are substantial variations in the onset temperatures and overall extent of these changes. Of the compositions studied, the composition of y, z = 0.6, 0.2 has the optimal combination of high energy density and reasonable thermal stability. The observations herein demonstrate that real-time electron microscopy provide direct insight into the changes that occur in cathode materials with temperature, allowing optimization of different alloy concentrations to maximize overall performance.</P>

우황청심원 관련 최근 연구 동향 : 국내 논문에 대한 고찰

이제원,백경민,백영두,임은영,장우석,전우현,정인권,Lee, Je-Won,Baek, Kyung-Min,Baek, Young-Doo,Im, Eun-Young,Chang, Woo-Seok,Cheon, Woo-Hyun,Chung, In-Kwon 대한한방내과학회 2010 大韓韓方內科學會誌 Vol.31 No.4

Objectives : Woohwangchungsim-won has been used for acute diseases such as cerebrovascular disease (stroke), heart disease. The aim of this study was to determine the effects, significance & necessity of Woohwangchungsim-won in acute stages of these disease by reviewing Korean articles about Woohwangchungsim-won. Methods : Article searches were performed on 8 major Korean web article search engine from January 1980 to August 2010. There were no restrictions on the types of publication, including grey articles. Results : Forty-three articles were included. Twenty one were efficacy tests, thirteen were comparative efficacy tests, eight were toxicity tests, and one was new method development. Eighteen articles were multicenter studies and twenty five were single center studies. Thirty two articles were animal testing, only ten articles were clinical articles. Thirty seven articles presented the composition and quantity of Woohwangchungsim-won, but six did not. Conclusions : The results of Korean articles about Woohwangchungsim-won can not strongly support the effects, significance & necessity of Woohwangchungsim-won. More rigorous studies are required for determination of the effects of Woohwangchungsim-won.