High-Sensitivity Method for Counting Low Concentrations of Particles in Liquids Using Centrifugation and Image Analysis

2000 ◽  
Vol 39 (Part 1, No. 6A) ◽  
pp. 3641-3644 ◽  
Author(s):  
Katsumi Yabusaki ◽  
Naoko Saitoh ◽  
Taisuke Hirono ◽  
Hiroki Matsui ◽  
Hiraki Okada
Keyword(s):  
Image Analysis ◽  
High Sensitivity ◽  
Low Concentrations ◽  
Sensitivity Method

scholarly journals A High-Sensitivity Method Based on Advanced Optical Waveguide Technology to Detect HBsAg

2021 ◽  
Vol 2021 ◽  
pp. 1-8
Author(s):  
Pingping Xiao ◽  
Xiaoxiong Hu
Keyword(s):  
Hepatitis B ◽  
Hepatitis B Surface Antigen ◽  
High Sensitivity ◽  
Lower Region ◽  
Minimum Value ◽  
Guided Mode ◽  
Gray Area ◽  
Low Concentrations ◽  
Measurement Results ◽  
Sensitivity Method

A novel method for the detection of the hepatitis B surface antigen (HBsAg) at low concentrations, using the ultrahigh-order guided mode acting as the probe excited by a symmetrical metal-cladding waveguide, is proposed. The method using the fact of the minimum value of the absorption peaks is proportional to the concentration of the sample to be detected to realize the detection of the hepatitis B virus at extremely low concentrations. It is realized that the low concentration of the HBsAg measurement relied on the principle of the minimum value of the absorption peak and the concentration having a good linear relationship. The measurement results indicate that this new method can precisely detect HBsAg at the concentrations in the lower region of the clinical gray area (i.e., below 20 ng/mL), the lower region of the current clinical gray area of HBsAg (below 20 ng/ml) can be measured, and the resolution can be reached (2 ng/mL).

scholarly journals All-Dielectric Metasurface for Sensing Microcystin-LR

Electronics ◽  
2021 ◽  
Vol 10 (11) ◽  
pp. 1363
Author(s):  
Binze Ma ◽  
Ao Ouyang ◽  
Juechen Zhong ◽  
Pavel A. Belov ◽  
Ravindra Kumar Sinha ◽  
...  
Keyword(s):  
Quality Factor ◽  
Bound States ◽  
High Sensitivity ◽  
Concentration Limit ◽  
Specific Recognition ◽  
Low Concentrations ◽  
Freshwater Bodies ◽  
Toxic Pollutant ◽  
Small Change ◽  
Dielectric Metasurface

Sensing Microcystin-LR (MC-LR) is an important issue for environmental monitoring, as the MC-LR is a common toxic pollutant found in freshwater bodies. The demand for sensitive detection method of MC-LR at low concentrations can be addressed by metasurface-based sensors, which are feasible and highly efficient. Here, we demonstrate an all-dielectric metasurface for sensing MC-LR. Its working principle is based on quasi-bound states in the continuum mode (QBIC), and it manifests a high-quality factor and high sensitivity. The dielectric metasurface can detect a small change in the refractive index of the surrounding environment with a quality factor of ~170 and a sensitivity of ~788 nm/RIU. MC-LR can be specifically identified in mixed water with a concentration limit of as low as 0.002 μg/L by a specific recognition technique for combined antigen and antibody. Furthermore, the demonstrated detection of MC-LR can be extended to the identification and monitoring of other analytes, such as viruses, and the designed dielectric metasurface can serve as a monitor platform with high sensitivity and high specific recognition capability.

scholarly journals The Double Face of Ketamine—The Possibility of Its Identification in Blood and Beverages

Molecules ◽  
2021 ◽  
Vol 26 (4) ◽  
pp. 813
Author(s):  
Magdalena Świądro ◽  
Paweł Stelmaszczyk ◽  
Irena Lenart ◽  
Renata Wietecha-Posłuszny
Keyword(s):  
Date Rape ◽  
Signal To Noise Ratio ◽  
High Sensitivity ◽  
Heroin Addiction ◽  
Assisted Extraction ◽  
Low Concentrations ◽  
High Concentrations ◽  
Rosé Wine ◽  
Tof Ms

The purpose of this study was to develop and validate a high-sensitivity methodology for identifying one of the most used drugs—ketamine. Ketamine is used medicinally to treat depression, alcoholism, and heroin addiction. Moreover, ketamine is the main ingredient used in so-called “date-rape” pills (DRP). This study presents a novel methodology for the simultaneous determination of ketamine based on the Dried Blood Spot (DBS) method, in combination with capillary electrophoresis coupled with a mass spectrometer (CE-TOF-MS). Then, 6-mm circles were punched out from DBS collected on Whatman DMPK-C paper and extracted using microwave-assisted extraction (MAE). The assay was linear in the range of 25–300 ng/mL. Values of limits of detection (LOD = 6.0 ng/mL) and quantification (LOQ = 19.8 ng/mL) were determined based on the signal to noise ratio. Intra-day precision at each determined concentration level was in the range of 6.1–11.1%, and inter-day between 7.9–13.1%. The obtained precision was under 15.0% (for medium and high concentrations) and lower than 20.0% (for low concentrations), which are in accordance with acceptance criteria. Therefore, the DBS/MAE/CE-TOF-MS method was successfully checked for analysis of ketamine in matrices other than blood, i.e., rose wine and orange juice. Moreover, it is possible to identify ketamine in the presence of flunitrazepam, which is the other most popular ingredient used in DRP. Based on this information, the selectivity of the proposed methodology for identifying ketamine in the presence of other components of rape pills was checked.

scholarly journals Measuring Thiols in Single Cultivar South African Red Wines Using 4,4-Dithiodipyridine (DTDP) Derivatization and Ultraperformance Convergence Chromatography-Tandem Mass Spectrometry

Foods ◽  
2018 ◽  
Vol 7 (9) ◽  
pp. 138 ◽  
Author(s):  
Mpho Mafata ◽  
Maria Stander ◽  
Baptiste Thomachot ◽  
Astrid Buica
Keyword(s):  
South African ◽  
Red Wine ◽  
High Sensitivity ◽  
White Wine ◽  
Wine Aroma ◽  
Low Concentrations ◽  
Varietal Thiols ◽  
Cultivar Differentiation ◽  
First Time ◽  
Ionization Methods

Wine varietal thiols are important contributors to wine aroma. The chemical nature of thiols makes them difficult to measure due to low concentrations, high sensitivity to oxidation, and low ionization. Methods for the measurement of thiols usually consist of multiple steps of sample preparation followed by instrumental measurement. Studies have collected large datasets of thiols in white wine but not in red wine, due to the lack of availability of suitable methods. In this study, for the first time, convergence chromatography was used to measure thiols in red wine at ultratrace levels with improved sensitivity compared to previous methods. Performance parameters (selectivity, linearity, limits of detection, precision, accuracy) were tested to demonstrate the suitability of the method for the proposed application. Red wine thiols were measured in South African Pinotage, Shiraz, and Cabernet Sauvignon wines (n = 16 each). Cultivar differentiation using the thiol profile was demonstrated.

scholarly journals Fast quantification of fluoroquinolones in environmental water samples using molecularly imprinted polymers coupled with internal extractive electrospray ionization mass spectrometry

RSC Advances ◽  
2018 ◽  
Vol 8 (31) ◽  
pp. 17293-17299 ◽  
Author(s):  
Wei Kou ◽  
Hua Zhang ◽  
Aisha Bibi ◽  
Mufang Ke ◽  
Jing Han ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Molecularly Imprinted Polymers ◽  
Water Samples ◽  
High Sensitivity ◽  
Environmental Water ◽  
Environmental Water Samples ◽  
Ionization Mass ◽  
Molecularly Imprinted ◽  
Imprinted Polymers ◽  
Sensitivity Method

A simple, fast and high-sensitivity method for quantification of fluoroquinolones in environmental water samples using MIPs-iEESI-MS.

scholarly journals Yohkoh Observations of Coronal Structures Surrounding Dark Filaments

1998 ◽  
Vol 167 ◽  
pp. 163-170
Author(s):  
Yutaka Uchida
Keyword(s):  
Image Analysis ◽  
High Latitude ◽  
Dynamic Range ◽  
High Sensitivity ◽  
Event Structure ◽  
Point Of View ◽  
Coronal Structure ◽  
Wide Dynamic Range ◽  
Proper Understanding ◽  
Coronal Structures

AbstractWe describe in this paper some of the findings of the Yohkoh satellite about the coronal structure surrounding dark filaments in the pre-event and initial phases of high latitude arcade formation events. The knowledge of pre-event structure and its change is essential for the proper understanding of the arcade flaring process from the causality point of view. The wide dynamic range and high sensitivity obervations by Yohkoh allow us to look into the faint structures and their changes with the use of a faint-feature-enhancing technique in the image analysis.

scholarly journals Prognostic Performance of a High-Sensitivity Cardiac Troponin I Assay in Patients with Non–ST-Elevation Acute Coronary Syndrome

2014 ◽  
Vol 60 (1) ◽  
pp. 158-164 ◽  
Author(s):  
Erin A Bohula May ◽  
Marc P Bonaca ◽  
Petr Jarolim ◽  
Elliott M Antman ◽  
Eugene Braunwald ◽  
...  
Keyword(s):  
Cardiac Troponin ◽  
Troponin I ◽  
High Sensitivity ◽  
Cardiovascular Death ◽  
Cardiac Troponin I ◽  
Fourth Generation ◽  
Prognostic Performance ◽  
Coronary Syndrome ◽  
Low Concentrations ◽  
Increased Risk

Abstract BACKGROUND High-sensitivity assays for cardiac troponin enable more precise measurement of very low concentrations and improved diagnostic accuracy. However, the prognostic value of these measurements, particularly at low concentrations, is less well defined. METHODS We evaluated the prognostic performance of a new high-sensitivity cardiac troponin I (hs-cTnI) assay (Abbott ARCHITECT) compared with the commercial fourth generation cTnT assay in 4695 patients with non–ST-segment elevation acute coronary syndromes (NSTE-ACS) from the EARLY-ACS (Early Glycoprotein IIb/IIIa Inhibition in NSTE-ACS) and SEPIA-ACS1-TIMI 42 (Otamixaban for the Treatment of Patients with NSTE-ACS) trials. The primary endpoint was cardiovascular death or new myocardial infarction (MI) at 30 days. Baseline cardiac troponin was categorized at the 99th percentile reference limit (26 ng/L for hs-cTnI; 10 ng/L for cTnT) and at sex-specific 99th percentiles for hs-cTnI. RESULTS All patients at baseline had detectable hs-cTnI compared with 94.5% with detectable cTnT. With adjustment for all other elements of the TIMI risk score, patients with hs-cTnI ≥99th percentile had a 3.7-fold higher adjusted risk of cardiovascular death or MI at 30 days relative to patients with hs-cTnI <99th percentile (9.7% vs 3.0%; odds ratio, 3.7; 95% CI, 2.3–5.7; P < 0.001). Similarly, when stratified by categories of hs-cTnI, very low concentrations demonstrated a graded association with cardiovascular death or MI (P-trend < 0.001). Use of sex-specific cutpoints did not improve prognostic performance. Patients with negative fourth generation cTnT (<10 ng/L) but hs-cTnI ≥26 ng/L were at increased risk of cardiovascular death/MI compared to those with hs-cTnI <26 ng/L (9.2% vs 2.9%, P = 0.002). CONCLUSIONS Application of this hs-cTnI assay identified a clinically relevant higher risk of recurrent events among patients with NSTE-ACS, even at very low troponin concentrations.

scholarly journals Use of Sodium Lauroyl Sarcosinate in a High-Sensitivity Protein Assay by Resonance Light Scattering Technique

2006 ◽  
Vol 11 (4) ◽  
pp. 400-406 ◽  
Author(s):  
Zhanguang Chen ◽  
Jinbin Liu ◽  
Yizeng Liang ◽  
Fenglian Ren
Keyword(s):  
Light Scattering ◽  
Serum Albumin ◽  
High Sensitivity ◽  
Resonance Light Scattering ◽  
Protein Assay ◽  
Sensitivity Method ◽  
Lauroyl Sarcosinate ◽  
Resonance Light Scattering Technique ◽  
Sodium Lauroyl Sarcosinate

A simple and high-sensitivity method has been developed for the determination of proteins in aqueous solutions by resonance light scattering (RLS) technique. At pH 3.4 and ionic strength 1.2 × 10-3, the weak RLS intensity of sodium lauroyl sarcosinate was greatly enhanced by the addition of proteins with the maximum peak located at 391 nm. Under the optimum conditions, the enhanced RLS intensities were in proportion to the concentrations of proteins in the range of 0.04 to 2.1 μg/mL for lysozyme, 0.0025 to 1.2 μg/mL for bovine serum albumin, 0.0075 to 0.9 μg/mL for human serum albumin, 0.02 to 1.4 μg/mL for γ-globulin, 0.02 to 0.8 μg/mL for egg albumin, and 0.01 to 0.6 μg/mL for hemoglobin. Low detection limits ranging from 0.8 ng/mL to 4.3 ng/mL depending on the kind of proteins that have been achieved. The protein concentrations in synthetic samples and real biochemical samples were determined with satisfactory results. This method presented here is not only sensitive and simple but also reliable and suitable for practical bioassay applications.

Sign in / Sign up

Export Citation Format

Share Document