• 한국수정란이식학회지
• /
• 제25권2호
• /
• pp.111-116
• /
• 2010

Sperm chromatin integrity is essential for successful fertilization and development of an embryo. Reported here is a quantification of DNA fragments which is intimately associated with reproductive potential to provide one of criteria for sperm chromatin integrity. Three sperm populations were considered: CONTROL (no treatment), UV irradiation (48mW/$cm^2$, 1h) and $H_2O_2$ (oxidative stress induced by hydrogen peroxide, 10 mM, 50 mM and 100 mM). DNA fragments in boar sperm were evaluated by using ligation-mediated quantitative real-time polymerase chain reaction (LM-qPCR) assay, which relies on real-time qPCR to provide a measure of blunt 5' phosphorylated double strand breaks in genomic DNA. The results in agarose gel electrophoresis showed no significant DNA fragmentation and no dose-dependent response to $H_2O_2$. However, the remarkable difference in shape and position was observed in melting curve of LM-qPCR. This result supported that the melting curve analysis of LM-qPCR presented here, could be more sensitive and accurate than previous DNA fragmentation assay method.

• 한국수소및신에너지학회논문집
• /
• 제13권2호
• /
• pp.151-158
• /
• 2002

The hydorgen storage alloys were produced by melting in arc melting furnace and then solution heat treated at $1,100^{\circ}C$ followed by pulverization. The chemical analysis on the samples showed that the major elements of misch metal(Mm) were La, Ce, Pr and Nd with impurity less than 1wt.%. X-ray diffraction indicated that the structure for these samples were a single phase of hexagonal with $CaCu_5$ type. Compared to the initial particle size $100{\sim}110{\mu}m$, the many fine cracks were found and particle size decreased to $14{\mu}m$ for $MmNi_{4.5}Mn_{0.5}$ after hydriding/dehydring test run. To activate the sample the vessel filled with hydrogen storage alloys was first evacuated for for at $70^{\circ}C$ and then treated for 10.5hr under hydrogen pressure of 20atm for $MmNi_{4.5}Mn_{0.5}$ alloy. The experimental data showed that the hydrogen storage alloy of $MmNi_{4.5}Mn_{0.5}$ had superior adsorption and description properties within a temperature rang of $40^{\circ}C{\sim}80^{\circ}C$ and also they had a good P-C-T curve.

• 접착 및 계면
• /
• 제3권3호
• /
• pp.15-21
• /
• 2002

Poly(ethylene-co-methylacrylate)(PEMA)를 KOH, 암모니아 수용액과 반응시켜 측쇄에 -COOK, $-CONH_2$, -COOH를 갖는 변성 폴리에틸렌 수분산액을 제조하였다. 수분산액을 캐스팅하여 필름으로 제조한 후 열적, 기계적, 열접착 특성을 조사하였다. 변성 폴리에틸렌 필름은 열이력에 따라 유리전이온도는 변화하지 않았으나 용융피크는 큰 변화가 관찰 되었다. 1차 가열 시 3개의 용융피크가 관찰되었으나 2차 가열 시에는 1개의 용융 피크가 관찰되었다. 아마이드 그룹의 함량을 증가시키면 인장 모듈러스가 증가하였으며 -COOK를 증가시키면 측기 중의 70 몰% 부근에서 최저의 인장강도를 나타내었다. 변성 폴리에틸렌 필름의 열접착은 폴리에틸렌 필름 보다 낮은 약 $80^{\circ}C$부터 가능하였으며 $90^{\circ}C$에서의 열접착 강도는 측기 중 약 70 몰% -COOK 농도에서 최저값을 나타내었다.

• 대한기계학회논문집B
• /
• 제24권9호
• /
• pp.1277-1284
• /
• 2000

To enhance heat transfer characteristics of water, micro-encapsulated octadecane of about $10{\mu}m$ diameter was added to water. Viscosity of the slurry was measured by using a capillary tube viscometer. The measured viscosity decreased as the temperature of the slurry increased, and it increased as the fraction of the capsules in the slurry increased. Thermal characteristics of the octadecane were studied by using a differential scanning calorimeter. The melting temperature and the melting energy of the octadecane were found to be $28.6^{\circ}$ and 34.4kcal/kg, respectively. The convective heat transfer characteristics of the slurry were investigated in a flow loop with a constant heat flux test section. Friction factor of the slurry flow was found to be similar to the expected curve by Petukhov. The Nusselt number of the slurry flow was highest when the octadecane melted. Effective thermal capacity of the 14.2% slurry was found to have 1.67 times of the thermal capacity of water.

• Journal of Applied Biological Chemistry
• /
• 제49권4호
• /
• pp.143-147
• /
• 2006

A rapid PCR-based assay for detecting hepatitis B viral DNA(HBV DNA) in serum and plasma was developed using a new PCR instrument named GenSpector(TMC-1000, Samsung electronics). PCR was carried out using a chip-based platform, which enabled 50 PCR cycles with internal controls, and melting-curve analysis in 30 minutes. Verification of the amplified HBV DNA product and the internal control was based on specific melting temperatures(Tm) analysis, executed by the GenSpector software. Primers were designed within the region conserved through HBV genotypes A to F. The lower limit of detection was 840 copies/ml serum, conducted with serial dilutions of a HBV DNA positive control(ACCURUN 325 series 700, Boston Biomedica Inc.). The assay was also compared to another assay for HBV DNA(Versant HBV DNA 3.0 assay, Bayer HealthCare) for 200 samples(each 100 clinical negative and positive samples). The sensitivity and specificity were 100% matched. This rapid PCR-based assay is specific, reproducible, and enables qualitative detection of HBV DNA.

• Applied Microscopy
• /
• 제45권2호
• /
• pp.95-100
• /
• 2015

The in-situ heating transmission electron microscopy experiment allows us to observe the time- and temperature-dependent dynamic processes in nanoscale materials by examining the same specimen. The temperature, which is a major experimental parameter, must be measured accurately during in-situ heating experiments. Therefore, calibrating the thermocouple readout of the heating holder prior to the experiment is essential. The calibration can be performed using reference materials whose phase-transformation (melting, oxidation, reduction, etc.) temperatures are well-established. In this study, the calibration experiment was performed with four reference materials, i.e., pure Sn, Al-95 wt%Zn eutectic alloy, NiO/carbon nanotube composite, and pure Al, and the calibration curve and formula were obtained. The thermocouple readout of the holder used in this study provided a reliable temperature value with a relative error of <4%.

• Nuclear Engineering and Technology
• /
• 제55권3호
• /
• pp.902-907
• /
• 2023

To understand the eutectic reaction mechanism and the relocation behavior of the core debris is indispensable for the safety assessment of core disruptive accidents (CDAs) in sodium-cooled fast reactors (SFRs). This paper addresses reaction products and their distribution of the eutectic melting/solidifying reaction of boron carbide (B₄C) and stainless-steel (SS). The influence of the existence of carbon on the B₄C-SS eutectic reaction was investigated by comparing the iron boride (FeB)-SS reaction by Raman spectroscopy with Multivariate Curve Resolution (MCR) analysis. The scanning electron microscopy with dispersive X-ray spectrometer was also used to investigate the elemental information of the pure metals such as Cr, Ni, and Fe. In the B₄C-SS samples, a new layer was formed between B₄C/SS interface, and the layer was confirmed that the formed layer corresponded to amorphous carbon (graphite) or FeB or Fe₂B. In contrast, a new layer was not clearly formed between FeB and SS interface in the FeB-SS samples. All samples observed the Cr-rich domain and Fe and Ni-rich domain after the reaction. These domains might be formed during the solidifying process.

• 한국약용작물학회지
• /
• 제23권6호
• /
• pp.439-445
• /
• 2015

Background : Correct identification of Panax species is important to ensure food quality, safety, authenticity and health for consumers. This paper describes a high resolution melting (HRM) analysis based method using internal transcribed spacer (ITS) and 5.8S ribosomal DNA barcoding regions as target (Bar-HRM) to obtain barcoding information for the major Panax species and to identify the origin of ginseng plant. Methods and Results : A PCR-based approach, Bar-HRM was developed to discriminate among Panax species. In this study, the ITS1, ITS2, and 5.8S rDNA genes were targeted for testing, since these have been identified as suitable genes for use in the identification of Panax species. The HRM analysis generated cluster patterns that were specific and sensitive enough to detect small sequence differences among the tested Panax species. Conclusion : The results of this study show that the HRM curve analysis of the ITS regions and 5.8S rDNA sequences is a simple, quick, and reproducible method. It can simultaneously identify three Panax species and screen for variants. Thus, ITS1HRM and 5.8SHRM primer sets can be used to distinguish among Panax species.

• Journal of Plant Biotechnology
• /
• 제45권1호
• /
• pp.9-16
• /
• 2018

DNA 바코딩 기술은 다양한 약용식물 종들의 기원을 확인하기 위해 폭넓게 이용되고 있는 연구방법이다. 그러나, 시중에 판매되고 있는 유사 식물종을 재료로 사용한 상품이나 혼재되어 있는 상품에서 확인하고자 하는 약용식물을 선별 가능한 실질적인 기술의 개발은 아직 많이 미흡한 실정이다. 최근에는 보다 신속하고 정확도가 높은 기술을 개발하고자 DNA barcoding (Bar) 기술과 high-resolution melting (HRM) curve pattern 분석기술을 혼합한 Bar-HRM 분석기술을 이용한 연구가 진행 중에 있다. 본 리뷰논문에서는 국제적인 시장에서 다양한 기원의 약용식물 판별에 실질적으로 적용 가능한 Bar-HRM 기술의 최근의 발전 과정과 그 이용에 대해서 정리하였다. 다양한 연구들을 통해서 일부 성공적인 결과들이 보고되고 있지만, 제한된 DNA 바코드 및 단일염기다형성(Single Nucleotide Polymorphism, SNP) 등 아직 해결되어야 할 과제들이 많다. 특히, 핵 내 바코드로는 ribosomal DNA의 internal transcribed sequence (ITS)단편 이외에는 보고된 사례가 한건도 없었다. 또한, 약용식물을 끓는 물로 추출하여 가공한 약탕, 잼, 젤리, 쥬스 등의 제품은 DNA 단편이 분해되어 분리가 안 되는 경우에는 DNA바코딩 기술을 적용하기가 곤란한 것으로 알려져 있으나 비교적 짧은 DNA단편이 요구되는 Bar-HRM 분석기술을 이용하여 일부 성공한 보고도 있어 향후 그 응용사례가 증가할 것으로 전망된다.

• Parasites, Hosts and Diseases
• /
• 제57권1호
• /
• pp.9-15
• /
• 2019

Melting temperature shift ($T_m-shift$) is a new detection method that analyze the melting curve on real-time PCR thermocycler using SYBR Green I fluorescent dye. To establish a $T_m-shift$ method for the detection of Ancylostoma ceylanicum and A. tubaeforme in cats, specific primers, with GC tail of unequal length attached to their 5' end, were designed based on 2 SNP loci (ITS101 and ITS296) of the internal transcribed spacer 1 (ITS1) sequences. The standard curve of $T_m-shift$ was established using the standard plasmids of A. ceylanicum (AceP) and A. tubaeforme (AtuP). The $T_m-shift$ method stability, sensitivity, and accuracy were tested with reference to the standard curve, and clinical fecal samples were also examined. The results demonstrated that the 2 sets of primers based on the 2 SNPs could accurately distinguish between A. ceylanicum and A. tubaeforme. The coefficient of variation (CV) of $T_m$- values of AceP and AtuP was 0.07% and 0.06% in ITS101 and was 0.06% and 0.08% in ITS296, respectively. The minimum detectable DNA concentration was $5.22{\times}10^{-6}$ and $5.28{\times}10^{-6}ng/{\mu}l$ samples of AceP and AtuP, respectively. The accuracy of $T_m-shift$ method reached 100% based on examination of 10 hookworm DNA samples with known species. In the clinical detection of hookworm in 69 stray cat fecal sample, the $T_m-shift$ detection results were consistent with the microscopic examination and successfully differentiated between the 2-hookworm species. In conclusion, the developed method is a rapid, sensitive and accurate technique and can provide a promising tool for clinical detection and epidemiological investigation of cat-derived hookworms.