• Title/Summary/Keyword: isothermal conditions

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Loop-mediated Isothermal Amplification (LAMP) for Detection of Streptococcus parauberis (Loop-mediated isothermal amplification (LAMP)법을 이용한 Streptococcus parauberis 의 신속 진단)

  • Moon, Kyung-Mi;Kim, Dong-Hwi;Heo, Moon-Soo
    • Journal of Life Science
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    • v.24 no.4
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    • pp.428-436
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    • 2014
  • Loop-mediated isothermal amplification (LAMP) technique relies on autocycling strand displacement DNA sysnthesis without template denaturation steps under isothermal conditions. LAMP has more advantages than modern PCR, as it requires only basic laboratory equipment like an isothermal water bath, oven, and heating cabinet. Hence, in this study, five random primers were designed with Streptococcus parauberis, shikimate kinase Arok gene sequences (Genbank accession number: CP0024711). Two primers were selected based on the ladder pattern. Other optimum reaction conditions like temperature, time, and sensitivity were established and confirmed with conventional SYBR-green PCR. Results confirmed that the designed random primers were species specific, without any non-target DNA amplification under isothermal conditions. Hence, this study suggests that LAMP techniques could be used in the diagnosis of fish pathogen, specifically S. parauberis.

Application of Layered System to the Outdoor Clothing - Through Water Vapor Permeability - (Layered System의 아웃도어 의류에의 적용 - 수분전달 특성을 중심으로 -)

  • Oh, Ae-Gyeong
    • Fashion & Textile Research Journal
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    • v.8 no.6
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    • pp.709-712
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    • 2006
  • The aim of this study is to find out comfortable combinations of layered system for outdoor activities through water vapor permeability. Layering fabrics is an effective way of controlling water transport properties in fabric systems for outdoor activities and analysis of these systems may be useful for designing comfortable clothing. Seven fabrics were chosen for the experiments: two fabrics for base layer, two for the middle layer and three for the shell layer. A total of 12 different layered systems, which are all possible combinations were established using selected fabrics. The water vapor permeability was measured using JIS L1099 under isothermal and non-isothermal conditions. It was found that layered system was working together as a whole having influence on each layer, though every layer offers varying degree of water vapor permeability. Furthermore, it was also found that an optimal combination of the three layered system does exist although the combination may differ according to the ways. The shell layer is the greatest effect of water vapor permeability under isothermal and non-isothermal conditions within layered system.

A Study on the Overlay Model for Description of Hysteresis Behavior of a Material under Non-isothermal Loading (변온 하중하에 있는 재료의 이력거동 예측을 위한 다층 모델에 관한 연구)

  • Kim, Sang-Ho;Seo, Dong-Hun;Yeo, Tae-In
    • Transactions of the Korean Society of Automotive Engineers
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    • v.18 no.3
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    • pp.133-142
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    • 2010
  • The present work focuses on the characterization of material parameters of the Overlay(multilinear hardening) model for analyzing the non-isothermal cyclic deformation. In the previous study, all the parameters were especially based on the Overlay theories, and a simple method was suggested to find out the best material parameters for the isothermal cyclic deformation analysis. Based on the previous research this paper f dther improves the isothermal parameters and suggests how to apply the isothermal parameters to the non-isothermal conditions especially for the description of TMF(Thermo-Mechanical Fatigue) hysteresis behavior. The parameters are determined and calibrated using 400 series stainless steel test data in the reference papers. For the implementation into ABAQUS, a user subroutine is developed by means of ABAQUS/UMAT. The finite element results show good agreement with test for the case of uniaxial non-isothermal cyclic loading, signifying the proposed method can be used in the TMF analysis of the converter-inserted heavy duty muffler system and the stainless steel exhaust-manifold system which are to be done in our future research.

Finite Element Analysis and Experimental Investigation of Non-isothermal Forming Processes for Aluminum-Alloy Sheet Metals (Part2:Analysis) (알루미늄 합금박판 비등온 성형공정의 유한요소 해석 및 실험적 연구 (제2부:해석))

  • 김성민;구본영;금영탁;김종호
    • Transactions of Materials Processing
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    • v.8 no.3
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    • pp.252-261
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    • 1999
  • The 3-dimensional finite element program is developed to analyze the non-isothermal forming processes of aluminum-alloy sheet metals. Bishop's method is introduced to solve the heat balance and force equilibrium equations. Also, Barlat's non-quadratic anisotropic yield function depicts the planar anisotropy of the aluminum-alloy sheet. To find an appropriate constitutive equation, four different forms are reviewed. For the verification of the reliability of the developed program, the computational try-outs of the non-isothermal cylindrical cupping processes of AL5052-H32 and Al1050-H16 are carried out. As results, the constitutive equation relating to strain and strain-rate, in which the constants are represented by the 5th-degree polynomials of temperature, is in good agreement with measurement. The computational try-outs can predict optimal forming conditions in non-isothermal forming processes.

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Experiments of Turbulent Thermal Mixing Phenomena Using Parallel Non-Isothermal Water Jets

  • Kim, Y.K.;Kim, J.M.;Lee, Y.B.;J.S. Hwang;H.Y. Nam
    • Proceedings of the Korean Nuclear Society Conference
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    • 1996.05b
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    • pp.36-41
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    • 1996
  • Turbulent thermal mixing experiments by the injection of two parallel non-isothermal water jets have been performed. The turbulent velocities and fluctuations under the isothermal conditions have been measured using LDV system. The velocity vectors have been plotted in two dimensions from the data measured at 29$\times$16 points. The thermal mixing experiments also have been conducted, where we used 45 K-type thermocouples with a sheath diameter of 0.020" which were fixed with 5 mm distance in a line at a measured height. The measured heights were 5, 10, 20, 30, 40 cm from the upper end of rectangular nozzles. We measured the turbulent temperatures under the various flow velocity conditions with 12$^{\circ}C$ $\leq$ $\Delta$T $\leq$4$0^{\circ}C$. The sampling frequency and sampling time were about 420 Hz and 10 seconds, respectively. The measured results of equal velocity parallel jets were analyzed axially and radially to obtain the variation of temperature fluctuation.tion.

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Detection of Salmonella typhi by Loop-mediated Isothermal Amplification Assay

  • Jo, Yoon-Kyung;Lee, Chang-Yeoul
    • Biomedical Science Letters
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    • v.14 no.2
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    • pp.115-118
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    • 2008
  • Salmonella typhi is frequent causes of foodborne illness and its detection is important for monitoring disease progression. In this study, by using general PCR and novel LAMP (Loop Mediated Isothermal Amplification) assay, we evaluated the usefulness of LAMP assay for detection of Salmonella typhi. In this LAMP assay, forward inner primer (FIP) and back inner primer (BIP) was specially designed for recognizing target invA gene. Target DNA was amplified and visualized as ladder-like pattern of bands on agarose gel within 60 min under isothermal conditions at $65^{\circ}C$. When the sensitivity and reproducibility of LAMP were compared to general PCR, there was no difference of reproducibility but sensitivity of LAMP assay was more efficient than PCR (the detection limit of LAMP assay was 30 fg, while the PCR assay was 3 pg). These results indicate that the LAMP assay is a potential and valuable means for detection of Salmonella typhi, especially for its rapidity, simplicity and low cost.

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A Study on Ventilation Effectiveness in the Non-isothermal Supply using Mixing and Displacement Ventilation Systems (비등온 급기조건에서 환기방식에 따른 환기효율 특성에 관한 연구)

  • 이재근;강태욱;윤석구;구재현;한정균;조민철
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.13 no.8
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    • pp.739-745
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    • 2001
  • The objective of this research is to analyze the ventilation effectiveness in the non-isothermal air supply using mixing and displacement ventilation systems for indoor air quality control and management. In this study, a ventilation effectiveness is evaluated in a simplified model chamber using a tracer gas technique of $CO^2$ gas injected into a supply duct as a function of ventilation rates, supply/extract sites and cooling/heating air supply. The ventilation effectiveness decreased with increasing ventilation rate on the cooling and heating conditions. And the ventilation effectiveness of case 3 (down supply and upper extract) was better thant that of case 1(upper supply and upper extract) and case 2(upper supply and down extract) with the cooling supply conditions. but for the heating supply air conditions, the ventilation effectiveness of case 2 was better than that of case 3 and case 1.

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Development of reverse-transcription loop-mediated isothermal amplification assays for point-of-care testing of human influenza virus subtypes H1N1 and H3N2

  • Ji-Soo Kang;Mi-Ran Seo;Yeun-Jun Chung
    • Genomics & Informatics
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    • v.20 no.4
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    • pp.46.1-46.7
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    • 2022
  • Influenza A virus (IAV) is the most widespread pathogen causing human respiratory infections. Although polymerase chain reaction (PCR)-based methods are currently the most commonly used tools for IAV detection, PCR is not ideal for point-of-care testing. In this study, we aimed to develop a more rapid and sensitive method than PCR-based tools to detect IAV using loop-mediated isothermal amplification (LAMP) technology. We designed reverse-transcriptional (RT)-LAMP primers targeting the hemagglutinin gene. RNAs from reference H1N1 and H3N2 showed specific RT-LAMP signals with the designed primers. We optimized the reaction conditions and developed universal reaction conditions for both LAMP assays. Under these conditions, the detection limit was 50 copies for both RT-LAMP assays. There was no non-specific signal to 19 non-IAV respiratory viruses, such as influenza B virus, coronaviruses, and respiratory syncytial viruses. Regarding the reaction time, a positive signal was detected within 25 min after starting the reaction. In conclusion, our RT-LAMP assay has high sensitivity and specificity for the detection of the H1 and H3 subtypes, making it suitable for point-of-care IAV testing.

Kinetics of Thermal Degradation of Polypropylene/Nanoclay/Wood Flour Nanocomposites

  • Mohan, D. Jagan;Lee, Sun-Young;Kang, In-Aeh;Doh, Geum-Hyun;Park, Byung-Dae;Wu, Qinglin
    • Journal of the Korean Applied Science and Technology
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    • v.24 no.3
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    • pp.278-286
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    • 2007
  • As a part of enhancing the performance of wood-plastic composites (WPC), polypropylene (PP)/ nanoclay (NC)/ wood flour (WF) nanocomposites were prepared using melt blending and injection molding process to evaluate their thermal stability. Thermogravimetric analysis (TGA) was employed to investigate thermal degradation kinetics of the nanocomposites both dynamic and isothermal conditions. Dynamic scans of the TGA showed an increased thermal stability of the nanocomposites at moderate wood flour concentrations (up to 20 phr, percentage based on hundred percent resin) while it decreased with the addition of 30 phr wood flour. The activation energy $(E_a)$ of thermal degradation of nanocomposites increased when nanoclay was added and the concentration of wood flour increased. Different equations were used to evaluate isothermal degradation kinetics using the rate of thermal degradation of the composites, expressed as weight loss (%) from their isothermal TGA curves. Degradation occurred at faster rate in the initial stages of about 60 min., and then proceeded in a gradual manner. However, nanocomposites with wood flour of 30 phr heated at $300^{\circ}C$ showed a drastic difference in their degradation behavior, and reached almost a complete decomposition after 40 min. of the isothermal heating. The degree of decomposition was greater at higher temperatures, and the residual weight of isothermal degradation of nanocomposites greatly varied from about 10 to 90%, depending on isothermal temperatures. The isothermal degradation of nanocomposites also increased their thermal stability with the addition of 1 phr nanoclay and of wood flour up to 20 phr. But, the degradation of PP100/NC1/MAPP3/WF30 nanocomposites with 30 phr wood flour occurs at a faster rate compared to those of the others, indicating a decrease in their thermal stability.

Effect of Isothermal Heat Treatment on the Microstructure and Mechanical Properties of Medium-Carbon Bainitic Steels (등온 열처리에 따른 중탄소 베이나이트강의 미세조직과 기계적 특성)

  • Lee, Ji-Min;Lee, Sang-In;Lim, Hyeon-Seok;Hwang, Byoungchul
    • Korean Journal of Materials Research
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    • v.28 no.9
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    • pp.522-527
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    • 2018
  • This study investigates the effects of isothermal holding temperature and time on the microstructure, hardness and Charpy impact properties of medium-carbon bainitic steel specimens. Medium-carbon steel specimens with different bainitic microstructures are fabricated by varying the isothermal conditions and their microstructures are characterized using OM, SEM and EBSD analysis. Hardness and Charpy impact tests are also performed to examine the correlation of microstructure and mechanical properties. The microstructural analysis results reveal that granular bainite, bainitic ferrite, lath martensite and retained austenite form differently in the specimens. The volume fraction of granular bainite and bainitic ferrite increases as the isothermal holding temperature increases, which decreases the hardness of specimens isothermally heat-treated at $300^{\circ}C$ or higher. The specimens isothermally heat-treated at $250^{\circ}C$ exhibit the highest hardness due to the formation of lath martensite, irrespective of isothermal holding time. The Charpy impact test results indicate that increasing isothermal holding time improves the impact toughness because of the increase in volume fraction of granular bainite and bainitic ferrite, which have a relatively soft microstructure compared to lath martensite for specimens isothermally heat-treated at $250^{\circ}C$ and $300^{\circ}C$.