• 제목/요약/키워드: limit of detection

검색결과 2,409건 처리시간 0.241초

Chemiluminescence immunochromatographic analysis for the quantitative determination of algal toxins

  • Pyo, Dongjin;Kim, Taehoon
    • ALGAE
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    • 제28권3호
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    • pp.289-296
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    • 2013
  • For the quantitative detection of algal toxin, microcystin, a chemiluminescence immunochromatographic assay method was developed. The developed system consists of four parts, chemiluminescence assay strip (nitrocellulose membrane), horse radish peroxidase labeled microcystin monoclonal antibodies, chemiluminescence substrate (luminol and hydrogen peroxide), and luminometer. The performance of the chemiluminescence immunochromatographic assay system was compared with high performance liquid chromatography (HPLC) detection. The detection limit of chemiluminescence immunochromatographic assay system is several orders of magnitude lower than with HPLC. The chemiluminescence immunochromatography and HPLC results correlated very well with the correlation coefficient ($r^2$) of 0.979.

Syntheses of 3-Pyrimidyl- and 3-Pyranyl-5,6-benzocoumarin Derivatives

  • El-Deen, Ibrahim M.;Al-Wakeel, El-Sayed I.;El-Mawla, Ahmed G.
    • Bulletin of the Korean Chemical Society
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    • 제23권4호
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    • pp.610-612
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    • 2002
  • A competitive enzyme-linked immunosorbent assay (ELISA) was developed for the quantitative detection of organophosphorus insecticide cyanophos. An analogue (hapten) of cyanophos was synthesized and was coupled to BSA to produce polyclonal antibodi es from rabbits. The antisera were screened against another hapten coupled to ovalbumin (OVA). Using the sera of highest specificity, an antigen-coated ELISA was developed, which showed an I50 of 310 ng/mL with the detection limit of 20 ng/mL. The antibodies showed negligible cross-reactivities with other organophosphorus pesticides except for parathion-methyl, which makes the assay suitable for the selective detection of cyanophos.

Motion Sensor Fault Detection and Failsafe Logic for Vehic1e Stability Control Systems (VSCs)

  • Yi, Kyongsu;Min, Kyongchan
    • Journal of Mechanical Science and Technology
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    • 제18권11호
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    • pp.1961-1968
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    • 2004
  • The design of a reliable and failsafe control system requires that sensor failures be detected and identified within acceptable time limit so that system malfunction can be prevented. This paper presents a model-based approach to sensor fault detection with applications to vehicle stability control systems. The effectiveness of the proposed method is illustrated through test data-based evaluation. Vehicle test data-based evaluation results show that the proposed fault management scheme can be used for the design of a failsafe VSCs.

Rhodamine Cyclen-based Fluorescent Chemosensor for the Detection of Cd2+

  • Shim, So-Young;Tae, Jin-Sung
    • Bulletin of the Korean Chemical Society
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    • 제32권spc8호
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    • pp.2928-2932
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    • 2011
  • A chemosensor based on a rhodamine-hydroxamate platform containing a pyridine and a cyclen binding units has been developed for the detection of $Cd^{2+}$ in aqueous solutions. The probe responds selectively toward $Cd^{2+}$ over other biologically relevant metal ions. The fluorescent probe shows 1:1 binding stoichiometry and the detection limit for $Cd^{2+}$ in water proved to be as low as 25 nM.

랜덤하프변환과 코너추출을 이용한 경사면의 장애물 위치 탐색 (Obstacle Position Detection on an Inclined Plane Using Randomized Hough Transform and Corner Detection)

  • 황선민;이민철
    • 제어로봇시스템학회논문지
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    • 제17권5호
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    • pp.419-428
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    • 2011
  • This paper suggests a judgement method for an inclined plane before entrance of it and the detection of obstacle position. Main idea is started from the assumption that obstacle is always on the bottom plane, and corner appears at this position. The process to detect the obstacle consists of three steps. First the 3D data using stereo matching is acquired to detect an obstacle. Second a bottom plane is extracted by using limit condition. Last the obstacle position is found by using Harris corner detection. Obstacle position detection on an inclined plane was verified by outdoor and indoor experiment. In error analysis, it is confirmed that an average error of obstacle detection in outdoor was larger than the error in indoor but the error are within about 0.030 m. This method will be applied to unmanned vehicles to navigate under various environment.

Evaluation of Various Real-Time Reverse Transcription Quantitative PCR Assays for Norovirus Detection

  • Yoo, Ju Eun;Lee, Cheonghoon;Park, SungJun;Ko, GwangPyo
    • Journal of Microbiology and Biotechnology
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    • 제27권4호
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    • pp.816-824
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    • 2017
  • Human noroviruses are widespread and contagious viruses causing nonbacterial gastroenteritis. Real-time reverse transcription quantitative PCR (real-time RT-qPCR) is currently the gold standard for the sensitive and accurate detection of these pathogens and serves as a critical tool in outbreak prevention and control. Different surveillance teams, however, may use different assays, and variability in specimen conditions may lead to disagreement in results. Furthermore, the norovirus genome is highly variable and continuously evolving. These issues necessitate the re-examination of the real-time RT-qPCR's robustness in the context of accurate detection as well as the investigation of practical strategies to enhance assay performance. Four widely referenced real-time RT-qPCR assays (Assays A-D) were simultaneously performed to evaluate characteristics such as PCR efficiency, detection limit, and sensitivity and specificity with RT-PCR, and to assess the most accurate method for detecting norovirus genogroups I and II. Overall, Assay D was evaluated to be the most precise and accurate assay in this study. A ZEN internal quencher, which decreases nonspecific fluorescence during the PCR, was added to Assay D's probe, which further improved the assay performance. This study compared several detection assays for noroviruses, and an improvement strategy based on such comparisons provided useful characterizations of a highly optimized real-time RT-qPCR assay for norovirus detection.

Development of a lateral flow dipstick test for the detection of 4 strains of Salmonella spp. in animal products and animal production environmental samples based on loop-mediated isothermal amplification

  • Wirawan Nuchchanart;Prapasiri Pikoolkhao;Chalermkiat Saengthongpinit
    • Animal Bioscience
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    • 제36권4호
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    • pp.654-670
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    • 2023
  • Objective: This study aimed to develop loop-mediated isothermal amplification (LAMP) combined with lateral flow dipstick (LFD) and compare it with LAMP-AGE, polymerase chain reaction (PCR), and standard Salmonella culture as reference methods for detecting Salmonella contamination in animal products and animal production environmental samples. Methods: The SalInvA01 primer, derived from the InvA gene and designed as a new probe for LFD detection, was used in developing this study. Adjusting for optimal conditions by temperature, time, and reagent concentration includes evaluating the specificity and limit of detection. The sampling of 120 animal product samples and 350 animal production environmental samples was determined by LAMP-LFD, comparing LAMP-AGE, PCR, and the culture method. Results: Salmonella was amplified using optimal conditions for the LAMP reaction and a DNA probe for LFD at 63℃ for 60 minutes. The specificity test revealed no cross-reactivity with other microorganisms. The limit of detection of LAMP-LFD in pure culture was 3×102 CFU/mL (6 CFU/reaction) and 9.01 pg/μL in genomic DNA. The limit of detection of the LAMP-LFD using artificially inoculated in minced chicken samples with 5 hours of pre-enrichment was 3.4×104 CFU/mL (680 CFU/reaction). For 120 animal product samples, Salmonella was detected by the culture method, LAMP-LFD, LAMP-AGE, and PCR in 10/120 (8.3%). In three hundred fifty animal production environmental samples, Salmonella was detected in 91/350 (26%) by the culture method, equivalent to the detection rates of LAMP-LFD and LAMP-AGE, while PCR achieved 86/350 (24.6%). When comparing sensitivity, specificity, positive predictive value, and accuracy, LAMP-LFD showed the best results at 100%, 95.7%, 86.3%, and 96.6%, respectively. For Kappa index of LAMP-LFD, indicated nearly perfect agreement with culture method. Conclusion: The LAMP-LFD Salmonella detection, which used InvA gene, was highly specific, sensitive, and convenient for identifying Salmonella. Furthermore, this method could be used for Salmonella monitoring and primary screening in animal products and animal production environmental samples.

초음파 디지털 자동 동조회로에 대한 연구 (A Study On The Ultrasonic Digital Auto-Tuning Circuit)

  • 신원철;이명호
    • 한국컴퓨터정보학회논문지
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    • 제7권1호
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    • pp.80-87
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    • 2002
  • 본 논문에서는 초음파를 이용한 동력을 활용하는 기기에 필요한 자동 주파수 추적 장치를 연구하고, 이를 개발하는 데 있다. 지금까지의 초음파 자동 주파수 추적은 아날로그 방식으로 이루어져 있으며 보다 정밀한 제어를 필요로 하는 분야에는 이 방식의 한계를 극복할 수 있는 새로운 방식의 추적장치를 필요로 한다.

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Automatic crack detection of dam concrete structures based on deep learning

  • Zongjie Lv;Jinzhang Tian;Yantao Zhu;Yangtao Li
    • Computers and Concrete
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    • 제32권6호
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    • pp.615-623
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    • 2023
  • Crack detection is an essential method to ensure the safety of dam concrete structures. Low-quality crack images of dam concrete structures limit the application of neural network methods in crack detection. This research proposes a modified attentional mechanism model to reduce the disturbance caused by uneven light, shadow, and water spots in crack images. Also, the focal loss function solves the small ratio of crack information. The dataset collects from the network, laboratory and actual inspection dataset of dam concrete structures. This research proposes a novel method for crack detection of dam concrete structures based on the U-Net neural network, namely AF-UNet. A mutual comparison of OTSU, Canny, region growing, DeepLab V3+, SegFormer, U-Net, and AF-UNet (proposed) verified the detection accuracy. A binocular camera detects cracks in the experimental scene. The smallest measurement width of the system is 0.27 mm. The potential goal is to achieve real-time detection and localization of cracks in dam concrete structures.

Simple and Ultrasensitive Chemically Amplified Electrochemical Detection of Ferrocenemethanol on 4-Nitrophenyl Grafted Glassy Carbon Electrode

  • Koh, Ahyeon;Lee, Junghyun;Song, Jieun;Shin, Woonsup
    • Journal of Electrochemical Science and Technology
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    • 제7권4호
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    • pp.286-292
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    • 2016
  • Chemically amplified electrochemical detection, redox-active probe being amplified its electrochemical anodic current by a sacrificial electron donor presenting in solution, holds great potential for simple and quantitative bioanalytical analysis. Herein, we report the chemically amplified electrochemical analysis that drastically enhanced a detection of ferrocenemethanol (analyte) by ferrocyanide (chemical amplifier) on 4-nitrophenyl grafted glassy carbon electrodes at $60^{\circ}C$. The glassy carbon electrode grafted with a 4-nitrophenyl group using an electrochemical reduction suppressed the oxidation of ferrocyanide and thus enabled detection of ferrocenemethanol with excellent selectivity. The ferrocenemethanol was detected down to an nM range using a linear sweep voltammetry under kinetically optimized conditions. The detection limit was improved by decreasing the concentration of the ferrocyanide and increasing temperature.