Extension of xMAP Food Allergen Detection Assay to Include Sesame

2019 ◽  
Vol 83 (1) ◽  
pp. 129-135 ◽  
Author(s):  
CHUNG Y. CHO ◽  
KATHERINE O. IVENS ◽  
WILLIAM L. NOWATZKE ◽  
JASON ROBOTHAM ◽  
MANSOUR SAMADPOUR ◽  
...  
Keyword(s):  
Food Allergen ◽  
Canola Oil ◽  
Dynamic Range ◽  
Signal To Noise Ratio ◽  
Sesame Oil ◽  
High Signal ◽  
North American Population ◽  
Detection Assay ◽  
Allergen Detection ◽  
Limit Of Quantitation

ABSTRACT An estimated 0.1 to 0.2% of the North American population is allergic to sesame, and deaths due to anaphylactic shock have been reported. Detecting and quantifying sesame in various food samples is critical to safeguard the allergic population by ensuring accurate ingredient labeling. Because of the modular nature of the xMAP Food Allergen Detection Assay (FADA), it was possible through method extension to add sesame as a validated additional analyte. Because raw and toasted sesame are both commonly used and the two display significantly different antigenicity, three antibodies, one monoclonal and two polyclonal, were conjugated to bead sets to ensure reliable detection. The modified xMAP FADA successfully detected sesame incurred or spiked in baked muffins, spice mix, canola oil, and in both raw and toasted sesame oils with limit of quantitation values ≤ 1.3 ppm of sesame. Canola oil, sesame oil, toasted sesame oil, and olive oil inhibited sesame detection, as did the detection of sesame incurred in foods containing oil (e.g., hummus). Despite this inhibition, the xMAP FADA was still able to reliably detect sesame at levels throughout the dynamic range of the assay (22 to 750 ng of protein per mL) in all the foods examined. Further, the high signal-to-noise ratio of the lowest calibration standard and preliminary studies conjugating the antibodies at higher concentrations indicate an ability to increase the sensitivity of the assay should the need arise. HIGHLIGHTS

scholarly journals Ab initiostructure determination of nanocrystals of organic pharmaceutical compounds by electron diffraction at room temperature using a Timepix quantum area direct electron detector

2016 ◽  
Vol 72 (2) ◽  
pp. 236-242 ◽  
Author(s):  
E. van Genderen ◽  
M. T. B. Clabbers ◽  
P. P. Das ◽  
A. Stewart ◽  
I. Nederlof ◽  
...  
Keyword(s):  
Electron Diffraction ◽  
Room Temperature ◽  
Dynamic Range ◽  
Signal To Noise Ratio ◽  
Three Dimensional ◽  
Direct Methods ◽  
Liquid Nitrogen Temperature ◽  
High Dynamic Range ◽  
Electron Diffraction Data ◽  
High Signal

Until recently, structure determination by transmission electron microscopy of beam-sensitive three-dimensional nanocrystals required electron diffraction tomography data collection at liquid-nitrogen temperature, in order to reduce radiation damage. Here it is shown that the novel Timepix detector combines a high dynamic range with a very high signal-to-noise ratio and single-electron sensitivity, enablingab initiophasing of beam-sensitive organic compounds. Low-dose electron diffraction data (∼0.013 e− Å−2 s−1) were collected at room temperature with the rotation method. It was ascertained that the data were of sufficient quality for structure solution using direct methods using software developed for X-ray crystallography (XDS,SHELX) and for electron crystallography (ADT3D/PETS,SIR2014).

scholarly journals Methods for Voltage-Sensitive Dye Imaging of Rat Cortical Activity With High Signal-to-Noise Ratio

2007 ◽  
Vol 98 (1) ◽  
pp. 502-512 ◽  
Author(s):  
Michael T. Lippert ◽  
Kentaroh Takagaki ◽  
Weifeng Xu ◽  
Xiaoying Huang ◽  
Jian-Young Wu
Keyword(s):  
Dynamic Range ◽  
Signal To Noise Ratio ◽  
Field Potential ◽  
High Sensitivity ◽  
High Dynamic Range ◽  
High Signal ◽  
Blue Dye ◽  
Voltage Sensitive Dye ◽  
Imaging Device

We describe methods to achieve high sensitivity in voltage-sensitive dye (VSD) imaging from rat barrel and visual cortices in vivo with the use of a blue dye RH1691 and a high dynamic range imaging device (photodiode array). With an improved staining protocol and an off-line procedure to remove pulsation artifact, the sensitivity of VSD recording is comparable with that of local field potential recording from the same location. With this sensitivity, one can record from ∼500 individual detectors, each covering an area of cortical tissue 160 μm in diameter (total imaging field ∼4 mm in diameter) and a temporal resolution of 1,600 frames/s, without multiple-trial averaging. We can record 80–100 trials of intermittent 10-s trials from each imaging field before the VSD signal reduces to one half of its initial amplitude because of bleaching and wash-out. Taken together, the methods described in this report provide a useful tool for visualizing evoked and spontaneous waves from rodent cortex.

scholarly journals A compact lightweight multipurpose ground-penetrating radar for glaciological applications

2011 ◽  
Vol 57 (206) ◽  
pp. 1113-1118 ◽  
Author(s):  
E.V. Vasilenko ◽  
F. Machío ◽  
J.J. Lapazaran ◽  
F.J. Navarro ◽  
K. Frolovskiy
Keyword(s):  
Dynamic Range ◽  
Time Window ◽  
Signal To Noise Ratio ◽  
High Signal ◽  
Peak Voltage ◽  
Recording Time ◽  
Single Person ◽  
Radio Echo Sounding ◽  
Power Peak ◽  
Ground Penetrating

AbstractWe describe a compact lightweight impulse radar for radio-echo sounding of subsurface structures designed specifically for glaciological applications. The radar operates at frequencies between 10 and 75 MHz. Its main advantages are that it has a high signal-to-noise ratio and a corresponding wide dynamic range of 132 dB due mainly to its ability to perform real-time stacking (up to 4096 traces) as well as to the high transmitted power (peak voltage 2800 V). The maximum recording time window, 40 μs at 100 MHz sampling frequency, results in possible radar returns from as deep as 3300 m. It is a versatile radar, suitable for different geophysical measurements (common-offset profiling, common midpoint, transillumination, etc.) and for different profiling set-ups, such as a snowmobile and sledge convoy or carried in a backpack and operated by a single person. Its low power consumption (6.6 W for the transmitter and 7.5 W for the receiver) allows the system to operate under battery power for >7 hours with a total weight of <9 kg for all equipment, antennas and batteries.

scholarly journals Special features of radio pulse spectral density analysis

2020 ◽  
Vol 27 (4) ◽  
pp. e103
Author(s):  
Andrew Chubykalo ◽  
Augusto Espinoza ◽  
Victor Kuligin
Keyword(s):  
Spectral Density ◽  
Dynamic Range ◽  
Signal To Noise Ratio ◽  
Radio Pulse ◽  
High Signal ◽  
Large Dynamic Range ◽  
High Duty Cycle ◽  
Radio Signals ◽  
Large Period ◽  
Density Analysis

The spectrum analysis of the periodic sequence radio pulses is often described in textbooks. However, if this method is applied to short radio pulses with a large period between them, then large errors occur. In this article, we described a new method of pulse gating. This method allows us to measure the spectral density of radio signals with high duty cycle. The main advantages of our method are a high signal-to-noise ratio, a large dynamic range of measurements, and a higher accuracy of spectral density measurements.

scholarly journals High sensitivity fluorescence up-conversion spectroscopy of 3MLCT emission of metal-organic complexes

2019 ◽  
Vol 205 ◽  
pp. 09009 ◽  
Author(s):  
Li Liu ◽  
Damianos Agathangelou ◽  
Thomas Roland ◽  
Olivier Crégut ◽  
Thibaud Duchanois ◽  
...  
Keyword(s):  
Dynamic Range ◽  
Signal To Noise Ratio ◽  
Emission Spectra ◽  
High Sensitivity ◽  
High Signal ◽  
Triplet States ◽  
Organic Complexes ◽  
Metal Organic ◽  
Set Up ◽  
Weak Luminescence

We demonstrate the implementation of a broadband fluorescence up-conversion set-up with high signal-to-noise ratio and dynamic range allowing for the detection of weak luminescence from triplet states in Fe(II) NHC complexes. Based on the experimentally determined radiative rates and the emission spectra, these states have dominant MLCT character.

scholarly journals Multi-laboratory validation of the xMAP—Food Allergen Detection Assay: A multiplex, antibody-based assay for the simultaneous detection of food allergens

PLoS ONE ◽  
2020 ◽  
Vol 15 (7) ◽  
pp. e0234899
Author(s):  
Eric A. E. Garber ◽  
Chung Y. Cho ◽  
Prasad Rallabhandi ◽  
William L. Nowatzke ◽  
Kerry G. Oliver ◽  
...  
Keyword(s):  
Food Allergen ◽  
Simultaneous Detection ◽  
Food Allergens ◽  
Detection Assay ◽  
Allergen Detection

Robustness Testing of the xMAP Food Allergen Detection Assay: A Multiplex Assay for the Simultaneous Detection of Food Allergens

2020 ◽  
Vol 83 (6) ◽  
pp. 1050-1056 ◽  
Author(s):  
PRASAD RALLABHANDI ◽  
CHUNG Y. CHO ◽  
WILLIAM L. NOWATZKE ◽  
KERRY G. OLIVER ◽  
ERIC A. E. GARBER
Keyword(s):  
Food Allergen ◽  
Incubation Temperature ◽  
Simultaneous Detection ◽  
Multiplex Assay ◽  
Food Allergens ◽  
Assay Procedure ◽  
Extraction Buffer ◽  
Detection Assay ◽  
Assay Performance ◽  
Allergen Detection

ABSTRACT The xMAP food allergen detection assay (xMAP FADA) can simultaneously detect 15 analytes (14 food allergens plus gluten) in one analysis. The xMAP FADA typically employs two antibody bead sets per analyte, providing built-in confirmation that is not available with other antibody-based assays. Before an analytical method can be used, its reliability must be assessed when conditions of the assay procedure are altered. This study was conducted to determine the effects on assay performance associated with changes in incubation temperature, amounts of the antibody bead cocktail, and concentrations of detection antibody and β-mercaptoethanol in the reduced-denatured extraction buffer. The analysis of buffered-detergent extracts revealed lower responses at 22°C than at 37°C, but temperature had no effect on the analysis of reduced-denatured extracts. Changes in β-mercaptoethanol and detection antibody concentrations had an effect on the detection of only milk in the reduced-denatured extracts. A slight change in the measured bead count was observed when one-fourth of the bead cocktail was used, and a large decrease in the bead count was noted when one-eighth of the recommended amount was used, but this number (≥25) was still sufficient to provide reliable results. Overall, the xMAP FADA was very robust to changes in the assay procedure, which may inadvertently occur. HIGHLIGHTS

Cross-reactivity profiles of legumes and tree nuts using the xMAP® multiplex food allergen detection assay

2017 ◽  
Vol 409 (25) ◽  
pp. 5999-6014 ◽  
Author(s):  
Chung Y. Cho ◽  
Carolyn Oles ◽  
William Nowatzke ◽  
Kerry Oliver ◽  
Eric A.E. Garber
Keyword(s):  
Food Allergen ◽  
Cross Reactivity ◽  
Tree Nuts ◽  
Detection Assay ◽  
Allergen Detection
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