• 반도체디스플레이기술학회지
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• 제4권3호
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• pp.11-15
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• 2005

This paper shows that carbon nanotubes can be applied to a nanopipette. Nano space in atomic force microscope multi wall carbon nanotube tips is filled with molecules and atoms with charges and then, the tips can be applied to nanopipette when the encapsulated media flow off under applying electrostatic farces. Since the nano space inside the tips can be refilled, the tips can be permanently used in ideal conditions of no chemical reaction and no mechanical deformation. Molecular dynamics simulations for nanopipette applications demonstrated the possibility of nano-lithography or single-metallofullerene-transistor array fabrication.

• 대한기계학회논문집
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• 제13권4호
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• pp.764-770
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• 1989

This paper analyze the steady state performance of a self-acting air lubricated slider bearing in hard disk/head system. Modified Reynolds' equation is derived from the steady state compressible Navier-Stokes equation, under slip-flow conditions. Finite difference technique and numerical procedure are described by using Newton-Raphson iteration method to slove the non-linear equations. These techniques are applied to conventional slider bearings and the effects of molecular mean free path(MMFP) for a recording surface of hard disk are shown. The calculation procedure developed here, wide applicabilities in practical head design procedures, and converges rapidly.

• E2M - 전기 전자와 첨단 소재
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• 제7권5호
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• pp.425-429
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• 1994

In this paper, we study on the plasma polymerized styrene as a negative electron-beam resist. Plasma polymerized thin film was prepared using an interelectrode inductively coupled gas-flow type reactor. We show that polymerization parameters of thin film affect sensitivity and etching resistance of the resist. Molecular weight distribution of plasma polymerized styrene is 1.41-3.93, and deposition rates of that are 32-383[.angs./min] with discharge power. Swelling and etching resistance becomes . more improved with increasing discharge power during plasma polymerization. Etch rate by RIE is higher than that by plasma etching.

• Molecules and Cells
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• 제39권1호
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• pp.26-30
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• 2016

Peroxiredoxins are ubiquitous thiol proteins that catalyse the breakdown of peroxides and regulate redox activity in the cell. Kinetic analysis of their reactions is required in order to identify substrate preferences, to understand how molecular structure affects activity and to establish their physiological functions. Various approaches can be taken, including the measurement of rates of individual steps in the reaction pathway by stopped flow or competitive kinetics, classical enzymatic analysis and measurement of peroxidase activity. Each methodology has its strengths and they can often give complementary information. However, it is important to understand the experimental conditions of the assay so as to interpret correctly what parameter is being measured. This brief review discusses different kinetic approaches and the information that can be obtained from them.

• FOCUS: LIFE SCIENCE
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• 제1호
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• pp.9.1-9.5
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• 2024

Method development for complex low molecular mass (LMM) samples using reversed-phase (RP) separation conditions presents significant challenges due to the presence of many unknown analytes over wide concentration ranges. This guide aims to optimize method parameters-column length (L), temperature (T), flow rate (F), and final mobile phase conditions (Øfinal)-to maximize separation peak capacity. Validated by prior research, this protocol benefits laboratories dealing with metabolomics, natural products, and contaminant screening. This practical guide provides a structured approach to maximizing peak capacity for complex LMM separations. It complements computational optimization strategies and offers a step-by-step method development process. The Snyder-Dolan test is highlighted as essential for determining the need for gradient or isocratic elution and guiding column length decisions. The decision tree framework helps analysts prioritize variable optimization to develop effective separation methods for complex samples.

• Nuclear Medicine and Molecular Imaging
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• 제43권5호
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• pp.487-494
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• 2009

목적: 작은 크기의 재조합 단일사슬 항체는 빠른 혈중 제거율과 종양의 항체 집적율이 증가되는 등의 장점을 가지고 있다. 반면에 항체의 작은 크기는 방사성 또는 형광물질의 표지를 위한 킬레이터 결합에 중요한 아미노산 그룹의 감소를 의미하기도 한다. 본 연구에서는 단일사슬 lym-1 염기서열 C-말단에 lysine 아미노산 태그를 삽입하여 형광 물질의 직접표지 및 그 표지수율 증가를 확인하고자 하였다. 대상 및 방법: 대장균 pET-22b (+) 벡터에 재조합 된 lysine 삽입 단일사슬 lym-1유전자는 대장균 BL21 (DE3)에 형질전환하여 발현하였다. 생산된 lysine lym-1 항체는 Ni-NTA 컬럽과 분자량 컬럼을 사용해 정제하였고. 단백질 전기 영동과 western blot을 통해 확인하였다. lysine lym-1 항체에 방사성 동위원소인 I-124, I-125, I-131 과 Tc-99m를 표지하여 그 수율을 확인하였으며 유세포계측기를 사용해 형광물질인 FITC가 직접표지된 라이신 lym-1 항체의 면역반응성을 사람의 버킷 림프종 세포주인 Raji 세포주에서 면역반응성을 확인하였다. 결과 Lysine도입 단일사슬 lym-1 항체는 두 과정의 정제를 통하여 획득하였으며 그 크기는 약 48 KDa이었고, 방사성동위원소인 I-124, I-125, I-131과 Tc-99m의 표지수율은 각각 >99%, >99%, >95%, >99%로 확인되었다. 유세포계측을 통한 lysine 도입 단일사슬 lym-1항체의 면역반응성은 기존의 단일사슬 lym-1항체와 유사함을 확인하였다. 결론: 재조합 lym-1 항체에 형광 물질을 직접 표지하기 위한 lysine 아미노산의 도입은 항체의 면역반응성 감소를 최소화 시키면서 직접표지 수율을 증가시킬 수 있는 유용한 방법임을 확인하였다.

• Journal of Microbiology and Biotechnology
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• 제26권4호
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• pp.790-798
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• 2016

Chlamydiae, obligate intracellular bacteria, are associated with a variety of human diseases. The chlamydial life cycle undergoes a biphasic development: replicative reticulate bodies (RBs) phase and infectious elementary bodies (EBs) phase. At the end of the chlamydial intracellular life cycle, EBs have to be released to the surrounded cells. Therefore, the interactions between Chlamydiae and cell death pathways could greatly influence the outcomes of Chlamydia infection. However, the underlying molecular mechanisms remain elusive. Here, we investigated host cell death after Chlamydia infection in vitro, in L929 cells, and showed that Chlamydia infection induces cell necrosis, as detected by the propidium iodide (PI)-Annexin V double-staining flow-cytometric assay and Lactate dehydrogenase (LDH) release assay. The production of reactive oxygen species (ROS), an important factor in induction of necrosis, was increased after Chlamydia infection, and inhibition of ROS with specific pharmacological inhibitors, diphenylene iodonium (DPI) or butylated hydroxyanisole (BHA), led to significant suppression of necrosis. Interestingly, live-cell imaging revealed that Chlamydia infection induced lysosome membrane permeabilization (LMP). When an inhibitor upstream of LMP, CA-074-Me, was added to cells, the production of ROS was reduced with concomitant inhibition of necrosis. Taken together, our results indicate that Chlamydia infection elicits the production of ROS, which is dependent on LMP at least partially, followed by induction of host-cell necrosis. To our best knowledge, this is the first live-cell-imaging observation of LMP post Chlamydia infection and report on the link of LMP to ROS to necrosis during Chlamydia infection.

• 공업화학
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• 제9권7호
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• pp.950-955
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• 1998

본 연구는 두 종류의 Polyethlene Glycol(PEG, Mw; 8000, 20000)을 cross-flow로 한외여과(막; 분획분자량 6000, 20000)함에 있어서 시간, 운전압력, 유입농도, 그리고 순환유량의 변화에 따라 투과유속과 제거율의 관계를 조사하는데 목적을 두고 있다. 실험진행에 있어서 운전압력은 7, 14, 28 psi의 3단계로, 순환유량은 1000 mL/min와 2000 mL/min 두 가지로, 그리고 유입농도도 100 mg/L과 1000 mg/L의 두가지로 하여 실행하였다. 투과유속은 PEG의 분자량과 농도가 작을수록 압력증가와 함께 증가하였으며, 겉보기제거율($R_o$)은 PEG의 분자량과 농도가 클수록 증가하였다. 그러나 압력이 증가되었을 때 $R_o$는 감소하였다. 일정한 압력하에서 PEG수용액의 투과유속과 $R_o$는 시간변화(8 h)에 관계없이 일정하였다. 순환유량의 변화에 있어서 투과유속에는 거의 영향이 없었으나, $R_o$는 순환유량이 큰 경우가 높게 나타났으며, 두 순환유량의 경우 모두 압력증가와 함께 $R_o$는 감소하였다. 한편, 투과유속과 조작압력의 거동을 분석하기 위해 사용된 투과도비($\alpha$)는 조작압력과 순환유량의 증가와 함께 증가하였으며, 모든 경우에서 1보다 작게 나타났기 때문에 농도분극현상을 분석할 수 있었다. 그리고 물질전달계수로부터 얻은 진제거율(R)은 압력증가와 함께 감소하였으며, 선유속과 PEG의 분자량이 클수록 높게 나타났다.

• 한국진공학회지
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• 제19권4호
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• pp.249-255
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• 2010

터보분자펌프(TMP)의 특성평가는 ISO, PNEUROP, DIN, JIS, AVS 등 세계 여러 나라의 표준제정기구에서 제정한 국제규격에 그 근거를 두고 있다. 한국표준과학연구원에서는 이러한 국제규격에 기반을 둔 터보분자펌프의 특성평가시스템을 자체 설계/제작하여 그 신뢰성을 확인하기 위해 개발품 및 상용품의 평가에 주력하고 있다. 터보분자펌프의 배기속도 측정방법으로서 기체흐름 영역에 따른 throughput method와 orifice method를 적용하고 있으나 측정게이지, 유량계 및 orifice conductance의 불확도 등 실질적으로 정확한 배기속도를 제시하기 위한 조건들의 제약 때문에 많은 측정오차를 포함하고 있다고 볼 수 있다. 이러한 배기속도의 측정오차를 줄이기 위한 하나의 고찰로서 본 논문에서는 $10^{-1}$ Pa-L/s 영역까지의 유량 주입범위를 가지는 기 구축된 정적법을 이용한 유량주입에 기반을 둔 throughput method를 이용하여 1000 L/s TMP의 측정 능력을 검증하고자 한다. 또한 분자류 영역인 orifice method를 사용할 경우 고진공영역, 미세유량 주입영역으로 진입할수록 커질 수밖에 없는 배기속도 측정 불확도를 최소화시키기 위해 검증된 유량을 이용한 conductance 값을 제시하여, 기 언급한 두 가지 배기 속도 측정 방법의 연속성을 유지하기 위한 실험적인 방법론을 제기하고자 한다.

• Journal of Acupuncture Research
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• 제17권2호
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• pp.169-186
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• 2000

To study anti-cancer effect and molecular biological mechanism of bee venom for aqua-acupuncture, the effects of bee venom on cell viability, apoptosis, and cell cycle were analyzed using MTT assay, tryphan blue assay, [3H]thymidine release assay, flow cytometric analysis, activity of caspase-3 protease activity assay, and immunocytometric analysis of PCNA. To explore whether anti-cancer effects of bee venom are associated with the transcriptional control of gene expression, quantitative RT-PCR analysis of apoptosis- and cell cycle-related genes was performed. The obtained results are summarized as follows: 1. The MTT assay demonstrated that cell viability was decreased by bee venom in a dose-dependant manner. 2. Significant induction of apoptosis was identified using tryphan blue assay, [$^3H$]thymidine release assay, and flow cytometric analysis of sub $G_1$ fraction. 3. In analysis of caspase-3 protease activity, the activity had increased significantly, in a dose-dependant manner. 4. Quantitative RT-PCR analysis of the apoptosis-related genes showed that Bcl-2 and $Bcl-X_L$ were down-regulated whereas Bax was up-regulated by bee venom treatment. 5. In flow cytometric analysis of cell cycle and immunocytometric analysis of PCNA expression, cell numbers of $G_1$ phase was increased by a dose-dependant manner. 6. In quantitative RT-PCR analysis of the cell cycle-related genes, p21, p27, and p57 were increased, while Cyclin D1, CDK4, c-Myc, c-Fos, and Histone H3 were decreased. In contrast, there were no remarkable changes in expression levels of CDC2 and c-Jun.