scholarly journals A multi-center clinical study comparing Sansure Magb and CAP/CTM HBV tests in the quantitative detection of HBV DNA

2016 ◽  
Vol 10 (07) ◽  
pp. 755-761 ◽  
Author(s):  
Xiaoyu Fu ◽  
Deming Tan ◽  
Xiaoguang Dou ◽  
Jinjun Chen ◽  
Juan Wu
Keyword(s):  
Developing Countries ◽  
Accurate Method ◽  
Magnetic Bead ◽  
Hbv Dna ◽  
Quantitative Detection ◽  
Plot Analysis ◽  
Highly Sensitive ◽  
Data Points ◽  
Quantitative Results ◽  
Chinese Company

Introduction: As the most reliable means of diagnosing hepatitis (HBV) infection and predicting the prognosis of HBV-related chronic liver disease, the COBAS AmpliPrep/COBAS TaqMan real-time polymerase chain reaction (PCR) (CAP/CTM) assay provides a highly sensitive and accurate method for quantifying HBV DNA. However, the high cost of the COBAS reagents is prohibitive in many developing countries. Thus, we compared the Sansure magnetic bead (Magb) assay, a novel technology developed by a Chinese company, with the CAP/CTM assay. Methodology: The reproducibility and sensitivity of the Sansure Magb assay were first validated using HBV DNA reference samples. Next, the quantitative results for the two assays using 635 blood samples collected from chronic hepatitis B patients and 10 healthy controls were compared. Results: The Sansure Magb assay showed high reproducibility and was at least as sensitive and specific as the CAP/CTM assay. Among the patient samples, 407 tested positive by both methods, with 386 (94.84%) showing quantitative differences of less than 1 log unit and 21 (5.16%) showing quantitative differences of between 1 and 2 log units. The results from the assays were closely correlated. Bland-Altman plot analysis showed that only 6.6% of the data points fell outside the 95% limits of agreement, which suggests that the differences between methods are clinically acceptable. Conclusions: This study demonstrates that the Sansure Magb assay is highly sensitive and reproducible. Based on its reduced cost, the Sansure Magb assay may be more applicable than the CAP/CTM assay for HBV diagnosis in developing countries such as China.

scholarly journals Quantitative Detection of Hepatitis B Virus DNA in Two International Reference Plasma Preparations

1999 ◽  
Vol 37 (1) ◽  
pp. 68-73 ◽  
Author(s):  
Klaus-Hinrich Heermann ◽  
Wolfram H. Gerlich ◽  
Michael Chudy ◽  
Stephan Schaefer ◽  
Reiner Thomssen
Keyword(s):  
Quality Control ◽  
Hepatitis B Virus ◽  
Hbv Dna ◽  
Quantitative Detection ◽  
Dna Molecules ◽  
B Virus ◽  
Quantitative Results ◽  
Genotype A ◽  
Limiting Dilution ◽  
Hybridization Assays

Quantitative detection of hepatitis B virus (HBV) in serum or plasma is of significance for monitoring of therapy and establishment of the prognosis of the disease, as well as for infectivity assessment and quality control of the diagnosis. Unfortunately, various commercially available test kits for HBV DNA yielded conflicting quantitative results, with differences of up to a factor of 120. The Eurohep Pathobiology Group has established two reference samples of plasma from HBV carriers and determined as accurately as possible the number of HBV DNA molecules in these samples. Plasma donations from two single highly viremic carriers of HBV genotype A (HBV surface antigen subtype adw2) and genotype D (ayw2/3), respectively, were collected, and coded dilutions of these samples were analyzed by members of the Eurohep Pathobiology Group. Quantitative results from the seven laboratories reporting consistent results were initially divergent. Limiting dilution and nested PCR assays suffered from incomplete DNA extraction. Hybridization assays used inaccurately quantitated cloned DNA as a reference. Two hybridization assays could not be calibrated directly with cloned HBV DNA, because virion-derived DNA reacted much less efficiently. After identification and elimination of these problems, limiting-dilution assays from three laboratories and hybridization assays from two producers generated consistent and concordant results: 2.7 × 109 HBV DNA molecules/ml (range, 2.1 × 109 to 3.4 × 109 HBV DNA molecules/ml) in the plasma from the carrier of genotype A and 2.6 × 109 HBV DNA molecules/ml (range, 2.1 × 109 to 3.0 × 109 HBV DNA molecules/ml in the plasma from the carrier of genotype D. The two Eurohep reference plasma samples have already been used for the standardization of test kits and in quality control trials, and the plasma from the carrier of genotype A will probably be the basis of a World Health Organization reference sample.

scholarly journals Magnetic Bead-Based Immunoassay Allows Rapid, Inexpensive, and Quantitative Detection of Human SARS-CoV-2 Antibodies

ACS Sensors ◽  
2021 ◽  
Author(s):  
Luciano F. Huergo ◽  
Khaled A. Selim ◽  
Marcelo S. Conzentino ◽  
Edileusa C. M. Gerhardt ◽  
Adrian R. S. Santos ◽  
...  
Keyword(s):  
Magnetic Bead ◽  
Quantitative Detection

Rapid, highly sensitive and quantitative detection of interleukin 6 based on SERS magnetic immunoassay

2021 ◽  
Vol 13 (15) ◽  
pp. 1823-1831
Author(s):  
Xiaomei Wang ◽  
Li Ma ◽  
Shijiao Sun ◽  
Tingwei Liu ◽  
Hao Zhou ◽  
...  
Keyword(s):  
Interleukin 6 ◽  
High Sensitivity ◽  
Quantitative Detection ◽  
Detection Time ◽  
Highly Sensitive ◽  
Sandwich Method

We have developed a SERS magnetic immunoassay method based on the principle of sandwich method for rapid and quantitative detection of IL-6. The developed SERS method has the advantages of high sensitivity and detection time is only 15 min.

scholarly journals On the mechanism of boundary lubrication. II. Wear prevention by addition agents

1940 ◽  
Vol 177 (968) ◽  
pp. 103-118 ◽  
Keyword(s):  
High Pressures ◽  
Preceding Paper ◽  
Accurate Method ◽  
Polar Compounds ◽  
Experimental Conditions ◽  
Group V ◽  
Highly Sensitive ◽  
Local Pressures ◽  
Steel Balls ◽  
Long Chain

If two metal surfaces slide over each other in the presence of a lubricant and under high load, high pressures and temperatures prevail a t those isolated spots which actually carry the load, leading to wear and possibly to breakdown. The action of wear preventing agents under these conditions has been studied in detail and it has been found that such agents are effective through their chemical polishing action, by which the load becomes distributed over a larger surface and local pressures and temperatures are decreased. Especially effective are compounds containing phosphorus or other elements of group V of the periodic system. These have been found to form a metal phosphide or homolog on the surface which is able to alloy with the metal surface, lowering its melting point markedly, and by this action aiding greatly in maintaining a polish. The wear experiments were carried out with a highly sensitive and accurate method which uses metal-plated steel balls as its sliding elements. Under the experimental conditions additions of 1.5% triphenyl phosphine or triphenyl arsine in white oil gave wear prevention factors of 7.2 and 12.2 respectively (relative to pure white oil). A further addition of 1% of a long chain polar compound is able to double the wear prevention factor obtained with the polishing agents and wear prevention factors as high as 17.6 have been observed. The specifically physical action of the long-chain polar compounds is discussed in the preceding paper.

A rapid and accurate method for screening T-2 toxin in food and feed using competitive AlphaLISA

2021 ◽  
Vol 368 (6) ◽  
Author(s):  
Liwen Zhang ◽  
Qingyu Lv ◽  
Yuling Zheng ◽  
Xuan Chen ◽  
Decong Kong ◽  
...  
Keyword(s):  
High Sensitivity ◽  
Accurate Method ◽  
Detection Methods ◽  
Cereal Crops ◽  
Detection Range ◽  
Highly Sensitive ◽  
Food And Feed ◽  
Good Repeatability ◽  
Feed Samples ◽  
Better Than

ABSTRACT T-2 is a common mycotoxin contaminating cereal crops. Chronic consumption of food contaminated with T-2 toxin can lead to death, so simple and accurate detection methods in food and feed are necessary. In this paper, we establish a highly sensitive and accurate method for detecting T-2 toxin using AlphaLISA. The system consists of acceptor beads labeled with T-2-bovine serum albumin (BSA), streptavidin-labeled donor beads and biotinylated T-2 antibodies. T-2 in the sample matrix competes with T-2-BSA for antibodies. Adding biotinylated antibodies to the test well followed by T-2 and T-2-BSA acceptor beads yielded a detection range of 0.03–500 ng/mL. The half-maximal inhibitory concentration was 2.28 ng/mL and the coefficient of variation was <10%. In addition, this method had no cross-reaction with other related mycotoxins. This optimized method for extracting T-2 from food and feed samples achieved a recovery rate of approximately 90% in T-2 concentrations as low as 1 ng/mL, better than the performance of a commercial ELISA kit. This competitive AlphaLISA method offers high sensitivity, good specificity, good repeatability and simple operation for detecting T-2 toxin in food and feed.

scholarly journals Quantitative Determination of Cd in Soil Using Laser-Induced Breakdown Spectroscopy in Air and Ar Conditions

Molecules ◽  
2018 ◽  
Vol 23 (10) ◽  
pp. 2492 ◽  
Author(s):  
Xiaodan Liu ◽  
Fei Liu ◽  
Weihao Huang ◽  
Jiyu Peng ◽  
Tingting Shen ◽  
...  
Keyword(s):  
Heavy Metal ◽  
Least Squares ◽  
Three Dimensional ◽  
Accurate Method ◽  
Laser Induced Breakdown Spectroscopy ◽  
Quantitative Detection ◽  
Support Vector ◽  
Least Squares Regression ◽  
Breakdown Spectroscopy ◽  
Laser Induced Breakdown

Rapid detection of Cd content in soil is beneficial to the prevention of soil heavy metal pollution. In this study, we aimed at exploring the rapid quantitative detection ability of laser- induced breakdown spectroscopy (LIBS) under the conditions of air and Ar for Cd in soil, and finding a fast and accurate method for quantitative detection of heavy metal elements in soil. Spectral intensity of Cd and system performance under air and Ar conditions were analyzed and compared. The univariate model and multivariate models of partial least-squares regression (PLSR) and least-squares support vector machine (LS-SVM) of Cd under the air and Ar conditions were built, and the LS-SVM model under the Ar condition obtained the best performance. In addition, the principle of influence of Ar on LIBS detection was investigated by analyzing the three-dimensional profile of the ablation crater. The overall results indicated that LIBS combined with LS-SVM under the Ar condition could be a useful tool for the accurate quantitative detection of Cd in soil and could provide reference for environmental monitoring.

Interference-free SERS tags for ultrasensitive quantitative detection of tyrosinase in human serum based on magnetic bead separation

2020 ◽  
Vol 1138 ◽  
pp. 150-157
Author(s):  
Dechan Lu ◽  
Xueliang Lin ◽  
Cairou Chen ◽  
Yudong Lu ◽  
Shangyuan Feng ◽  
...  
Keyword(s):  
Human Serum ◽  
Magnetic Bead ◽  
Quantitative Detection ◽  
Magnetic Bead Separation ◽  
Sers Tags

scholarly journals DETERMINISTIC INITIALIZATION OF THE K-MEANS ALGORITHM USING HIERARCHICAL CLUSTERING

2012 ◽  
Vol 26 (07) ◽  
pp. 1250018 ◽  
Author(s):  
M. EMRE CELEBI ◽  
HASSAN A. KINGRAVI
Keyword(s):  
Clustering Algorithm ◽  
Large Data ◽  
Large Data Sets ◽  
Data Sets ◽  
Partitional Clustering ◽  
Highly Sensitive ◽  
Data Points ◽  
Initial Placement ◽  
Random Initialization ◽  
Common Deficiency

K-means is undoubtedly the most widely used partitional clustering algorithm. Unfortunately, due to its gradient descent nature, this algorithm is highly sensitive to the initial placement of the cluster centers. Numerous initialization methods have been proposed to address this problem. Many of these methods, however, have superlinear complexity in the number of data points, making them impractical for large data sets. On the other hand, linear methods are often random and/or order-sensitive, which renders their results unrepeatable. Recently, Su and Dy proposed two highly successful hierarchical initialization methods named Var-Part and PCA-Part that are not only linear, but also deterministic (nonrandom) and order-invariant. In this paper, we propose a discriminant analysis based approach that addresses a common deficiency of these two methods. Experiments on a large and diverse collection of data sets from the UCI machine learning repository demonstrate that Var-Part and PCA-Part are highly competitive with one of the best random initialization methods to date, i.e. k-means++, and that the proposed approach significantly improves the performance of both hierarchical methods.

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