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Enhancement of electrocatalytic activity of gold nanoparticles by sonochemical treatment
Lee, Yang-Hee,Kim, Gunn,Joe, Minwoong,Jang, Ji-Hoon,Kim, Juyeong,Lee, Kwang-Ryeol,Kwon, Young-Uk Royal Society of Chemistry 2010 Chemical communications Vol.46 No.31
<P>We demonstrate that gold nanoparticles can become catalytically active for the electrochemical hydrogen oxidation reaction by a sonication treatment. Experimental data and theoretical calculations indicate that the activity arises from the supercooled molten state of gold nanoparticles which are enriched with coordinatively unsaturated gold atoms.</P> <P>Graphic Abstract</P><P>Gold nanoparticles can become an active electrocatalyst for the oxidation of hydrogen by sonochemical treatment. <IMG SRC='http://pubs.rsc.org/services/images/RSCpubs.ePlatform.Service.FreeContent.ImageService.svc/ImageService/image/GA?id=c0cc00950d'> </P>
Intensity Histogram-Based Reliable Image Analysis Method for Bead-Based Fluorescence Immunoassay
Lee Sanghyun,Kim Juyeong,Bae Pan Kee,Lee Sangmin,김호진 한국바이오칩학회 2024 BioChip Journal Vol.18 No.1
Bead-based fluorescence immunoassay is drawing attention as a next-generation technology in disease diagnosis owing to its high sensitivity and multiplexing capability. Fluorescence imaging of beads is typically used to determine their mean fluorescence intensity. However, the mean intensity can be evaluated differently depending on the analysis methods [such as the shape and size of the region of interest (ROI)]. To address these problems, this study proposes a highly reliable and reproducible image analysis method utilizing a fluorescence intensity-based effective pixel extraction technique. Various potential sources of defective signals (e.g., fluorescence aggregation, non-specific antigen–antibody reactions, and bead defects) can be prevented from contributing to the average value by selectively extracting pixels representing the specific reactions of antigens and antibodies in the ROI. In this study, we fabricated a microfluidic chip composed of multiple bead- based detection lines, performed fluorescence immunoassay, and then compared the mean fluorescence intensity calculated from the fluorescence images with that of a conventional analysis method. Using the conventional method, the evaluated average mean intensity value of beads varied significantly based on the size of the ROI with the coeffi cients of variation ranging from approximately 29–95%. In contrast, the effective pixel extraction method resulted in a coefficient of variation of approximately 3–7% under varying ROI size. Furthermore, the coefficients of variation for four detection lines containing various types of defective signals signifi cantly decreased from approximately 7.1% to 2.6%. The proposed technique will help in minimizing the analysis deviation caused by different ROI selections or defective signals in fluorescent image-based immunoassays.
불레기말 추출물이 난소를 절제한 갱년기 장애 모델의 혈청 지질 변화 및 골 형성에 미치는 영향
이주영(Juyeong Lee),김보경(Bokyung Kim),박미화(Mi-Hwa Park),최경하(Kyung-Ha Choi),공창숙(Changsuk Kong),이상현(Sang-Hyeon Lee),김육용(Yuck Yong Kim),유기환(Ki Hwan Yu),김미향(Mihyang Kim) 한국식품영양과학회 2016 한국식품영양과학회지 Vol.45 No.4
본 연구에서는 갱년기 장애를 유발한 흰쥐의 혈중 지질 농도, 항혈소판 응집능, 혈중 alkaline phosphatase(ALP) 활성 및 collagen 함량 검토를 통하여 갈조류인 불레기말 추출물의 효과를 검토하고자 하였다. 9주령 흰쥐를 각 군당 6마리씩 난소절제 모의 수술군(SHAM군), 난소절제군(OVXCON군), 난소절제 후 불레기말 추출물 50 mg/kg bw 투여군(OVX-CS50군) 및 200 mg/kg bw 투여군(OVX-CS200군)의 4군으로 나누어 시술 후 6주간 추출물을 투여하며 사육하였다. 혈청 중 총콜레스테롤 및 LDL-콜레스테롤의 경우 난소절제군이 비 난소절제군과 비교해 증가하는 경향을 나타내었으나, 난소절제 후 불레기말 추출물 200 mg/kg bw의 투여로 인해 유의적으로 감소하는 결과를 나타내었다. 또한, 난소절제로 인해 증가한 중성지질 함량은 불레기말 추출물의 투여로 인해 OVX-CS50군 및 OVX-CS200군 모두에서 유의적으로 감소하는 결과가 나타났다. 항혈소판 응집력을 검토한 결과 난소절제에 의해 혈소판 응집력이 증가하였으나 불레기말 추출물 50 mg/kg bw 투여로 인해 응집시간이 지연되는 결과를 나타내었다. 한편 골아세포 분화의 초기 표지자인 혈중 ALP 활성은 난소절제로 인해 증가하였으나, 불레기말 추출물을 투여한 결과 감소하는 경향이 나타났다. 결합조직 중의 collagen 함량은 연골, 뼈, 피부에서 난소절제로 인해 감소한 콜라겐 함량이 불레기말 추출물 투여로 인해 유의적으로 증가하였다. 이상과 같이 불레기말 추출물을 이용하여 난소절제로 갱년기를 유발한 동물에 대한 지질변화 및 골 형성에 대한 영향을 검토한 결과 불레기말 추출물이 지질 및 혈소판 응집능에 개선 효과를 나타내었으며, 결합조직 중 콜라겐 합성을 촉진하는 결과가 나타났으므로 이를 활용하여 식품 소재 및 기능성 식품 개발에 접목해 이용할 수 있을 것으로 생각된다. In this study, the effects of Colpomenia sinuosa (CS) extract on serum lipid level and bone formation in an ovariectomized animal model were investigated. Twenty four nine-week old female Sprague-Dawley rats were randomly assigned to four groups: sham-operated rats (SHAM), ovariectomized control rats (OVX-CON), and ovariectomized rats supplemented with CS extract at 50 mg/kg bw (OVX-CS50) or 200 mg/kg bw (OVX-CS200). Three OVX groups were surgically ovariectomized while the SHAM group was sham-operated. CS extract was orally administrated at 1 mL per day. Analysis of serum lipid contents found that the total cholesterol, triglyceride, and low density lipoprotein cholesterol levels in the OVX-CON group were higher than those in the SHAM group. Notably, upon administration of CS extract after ovariectomy, triglyceride levels tended to significantly decrease. In addition, platelet aggregation ability decreased in groups treated with CS extract compared to the OVX-CON group. Serum alkaline phosphatase activity as an indicator of bone formation was lower in the CS extract group compared to the OVX-CON group. Collagen contents in bone and cartilage were reduced by ovariectomy, whereas the CS extract-supplemented groups exhibited higher concentrations in bone. According to these results, CS extract improved serum lipid parameters and osteogenesis in ovariectomized rats.
실험계획법을 이용한 GDI연료펌프의 맥동저감을 위한 댐퍼 최적설계
김주영(Juyeong Kim),노진이(Jinyee Noh),이종욱(Jongwook Lee),김경남(Kyungnam Kim),박형종(Hyoungjong Park),황재근(Jaekeun Hwang),이연홍(Yeonhong Lee),윤길호(Gilho Yoon) 한국자동차공학회 2011 한국자동차공학회 학술대회 및 전시회 Vol.2011 No.11
This study optimizes the profile of the diaphragm of a pressure pulsation damper structure in a high-pressure GDI engine system which is now under development by applying the design of experiment (DOE). As a high pressure pulsation ranging from 0 to 10 Bar deteriorates the performance of GDI engine, it is necessary to attenuate the large amplitude of fluid pulsation pressure of Gasoline fuel directly injected into GDI engine. In the development of this pressure damper, it becomes an issue to design optimal profiles of the enveloping diaphragms in terms of pulsation efficiency and mechanical stress for the sake of safety. Thus, this research develops a new finite element procedure considering the internal pressure variation by assuming the isoenthalpy state of the enveloped Helium gas inside the damper and integrates the iterative finite element procedure with the design of experiment (DOE).
이주영(Juyeong Lee),홍용근(Yong-guen Hong),이현석(Hyunseok Lee) 대한전자공학회 2015 전자공학회논문지 Vol.52 No.2
이 논문은 SIMD 구조를 갖는 프로세서에서 FFT 연산을 효과적으로 처리하는 방법에 대한 것이다. FFT는 디지털 신호처리 분야에서 널리 사용되는 범용 알고리즘으로 이의 효과적인 처리는 성능 향상에 있어서 매우 중요하다. Bruun 알고리즘은 반복적인 인수분해를 통해 구현되는 FFT 알고리즘으로, 널리 사용되는 Cooley-Tukey 알고리즘에 비해 복소수 곱셈이 아닌 실수 곱셈으로 대부분의 동작을 수행하는 장점을 가지고 있으나, SIMD 프로세서에서 구현하는 데는 벡터 데이터의 정렬 형태가 복잡하고 연산에 필요한 계수들을 저장할 메모리를 더 필요로 하는 단점이 있다. 실험 결과에 따르면 길이 1024인 FFT 연산을 SIMD 프로세서에서 수행하는데 있어서 Bruun 알고리즘은 Cooley-Tukey 알고리즘에 비해서 약 1.2배의 더 높은 처리 성능을 보이지만, 약 4 배 더 큰 데이터 메모리를 필요로 한다. 따라서 데이터 메모리에 대한 제약이 큰 경우가 아니라면 SIMD 프로세서에서 Bruun 알고리즘이 FFT 연산에 적합하다. This paper discusses the implementation of Bruun’s FFT on a SIMD processor. FFT is an algorithm used in digital signal processing area and its effective processing is important in the enhancement of signal processing performance. Bruun"s FFT algorithm is one of fast Fourier transform algorithms based on recursive factorization. Compared to popular Cooley-Tukey algorithm, it is advantageous in computations because most of its operations are based on real number multiplications instead of complex ones. However it shows more complicated data alignment patterns and requires a larger memory for storing coefficient data in its implementation on a SIMD processor. According to our experiment result, in the processing of the FFT with 1024 complex input data on a SIMD processor, The Bruun’s algorithm shows approximately 1.2 times higher throughput but uses approximately 4 times more memory (20 Kbyte) than the Cooley-Tukey algorithm. Therefore, in the case with loose constraints on silicon area, the Bruun’s algorithm is proper for the processing of FFT on a SIMD processor.