scholarly journals A Homogeneous, Nonradioactive High-Throughput Fluorogenic Protein Phosphatase Assay

2004 ◽  
Vol 9 (3) ◽  
pp. 223-231 ◽  
Author(s):  
Kevin Kupcho ◽  
Kevin Hsiao ◽  
Bob Bulleit ◽  
Said A. Goueli
Keyword(s):  
Dynamic Range ◽  
Signal To Noise Ratio ◽  
Protein Phosphatases ◽  
High Signal ◽  
Cellular Regulation ◽  
Peptide Substrates ◽  
Cellular Processes ◽  
Low Concentrations ◽  
Critical Components ◽  
Phosphatase Assay

Protein phosphatases are critical components in cellular regulation; they do not only act as antioncogenes by antagonizing protein kinases, but they also play a positive regulatory role in a variety of cellular processes that require dephosphorylation. Thus, assessing the function of these enzymes necessitates the need for a robust, sensitive assay that accurately measures their activities. The authors present a novel, homogeneous, and nonradioactive assay to measure the enzyme activity of low concentrations of several protein phosphatases (phosphoserine/phosphothreonine phosphatases and phosphotyrosine phosphatases). The assay is based on the use of fluorogenic peptide substrates (rhodamine 110, bis-phosphopeptide amide) that do not fluoresce in their conjugated form, which is resistant to cleavage by aminopeptidases. However, upon dephosphorylation by the phosphatase of interest, the peptides become cleavable by the protease and release the highly fluorescent-free rhodamine 110. The assay is rapid, can be completed in less than 2 h, and can be carried out in multiwell plate formats such as 96-, 384-, and 1536-well plates. The assay has an excellent dynamic range, high signal-to-noise ratio, and a Z′ of more than 0.8, and it is easily adapted to a robotic system for drug discovery programs targeting protein phosphatases.

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.

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 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 Genetically Encoded Fluorescent Indicators for Imaging Brain Chemistry

Biosensors ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 116
Author(s):  
Xiaoke Bi ◽  
Connor Beck ◽  
Yiyang Gong
Keyword(s):  
Dynamic Range ◽  
Signal To Noise Ratio ◽  
Spatial Scales ◽  
High Signal ◽  
Spatiotemporal Resolution ◽  
Brain Chemistry ◽  
Fluorescent Indicators ◽  
Recent Developments

Genetically encoded fluorescent indicators, combined with optical imaging, enable the detection of physiologically or behaviorally relevant neural activity with high spatiotemporal resolution. Recent developments in protein engineering and screening strategies have improved the dynamic range, kinetics, and spectral properties of genetically encoded fluorescence indicators of brain chemistry. Such indicators have detected neurotransmitter and calcium dynamics with high signal-to-noise ratio at multiple temporal and spatial scales in vitro and in vivo. This review summarizes the current trends in these genetically encoded fluorescent indicators of neurotransmitters and calcium, focusing on their key metrics and in vivo applications.

A FPGA-PC Based Acoustic Emission System with Logarithmic Preamplifier for Fracture Monitoring

2013 ◽  
Vol 592-593 ◽  
pp. 541-544 ◽  
Author(s):  
Marek Vondra ◽  
Gabriel Cséfalvay ◽  
Petr Sedlak
Keyword(s):  
Acoustic Emission ◽  
Dynamic Range ◽  
Signal To Noise Ratio ◽  
Quantization Noise ◽  
High Signal ◽  
Source Characterization ◽  
Nondestructive Technique ◽  
Emission System ◽  
Low Levels ◽  
Input Gain

Acoustic emission (AE) is one of the most used nondestructive technique since it offers a great potential due to its ability of quantitative evaluation such as source location and source characterization. A common set of recorded acoustic emission signals has an extraordinarily wide dynamic range. Thus, the input gain of the A/D converter plays a key role due in information loss considering limitation of high signal amplitudes and domination of quantization noise at low levels. The usage of a logarithmic preamplifier extends the dynamic range of conventional A/D converters, thus increases the accuracy and signal-to-noise ratio of weak acoustic emission signals.

scholarly journals Synchrotron X-ray diffraction experiments with a prototype hybrid pixel detector

2011 ◽  
Vol 45 (1) ◽  
pp. 38-47 ◽  
Author(s):  
C. Le Bourlot ◽  
P. Landois ◽  
S. Djaziri ◽  
P.-O. Renault ◽  
E. Le Bourhis ◽  
...  
Keyword(s):  
Dynamic Range ◽  
Signal To Noise Ratio ◽  
High Dynamic Range ◽  
High Signal ◽  
Pixel Detector ◽  
X Ray Diffraction ◽  
X Ray ◽  
Area Detector ◽  
Duplex Steel ◽  
Scientific Results

A prototype X-ray pixel area detector (XPAD3.1) has been used for X-ray diffraction experiments with synchrotron radiation. The characteristics of this detector are very attractive in terms of fast readout time, high dynamic range and high signal-to-noise ratio. The prototype XPAD3.1 enabled various diffraction experiments to be performed at different energies, sample-to-detector distances and detector angles with respect to the direct beam, yet it was necessary to perform corrections on the diffraction images according to the type of experiment. This paper is focused on calibration and correction procedures to obtain high-quality scientific results specifically developed in the context of three different experiments, namely mechanical characterization of nanostructured multilayers, elastic–plastic deformation of duplex steel and growth of carbon nanotubes.

scholarly journals Bioluminescent Sensors for Ca++ Flux Imaging and the Introduction of a New Intensity-Based Ca++ Sensor

2021 ◽  
Vol 9 ◽  
Author(s):  
Jie Yang ◽  
Carl Hirschie Johnson
Keyword(s):  
Dynamic Range ◽  
Cultured Cells ◽  
Signal To Noise Ratio ◽  
Dynamic Change ◽  
Living Cells ◽  
High Signal ◽  
Pros And Cons ◽  
Rapid Kinetics

Sensitive detection of biological events is a goal for the design and characterization of sensors that can be used in vitro and in vivo. One important second messenger is Ca++ which has been a focus of using genetically encoded Ca++ indicators (GECIs) within living cells or intact organisms in vivo. An ideal GECI would exhibit high signal intensity, excellent signal-to-noise ratio (SNR), rapid kinetics, a large dynamic range within relevant physiological conditions, and red-shifted emission. Most available GECIs are based on fluorescence, but bioluminescent GECIs have potential advantages in terms of avoiding tissue autofluorescence, phototoxicity, photobleaching, and spectral overlap, as well as enhancing SNR. Here, we summarize current progress in the development of bioluminescent GECIs and introduce a new and previously unpublished biosensor. Because these biosensors require a substrate, we also describe the pros and cons of various substrates used with these sensors. The novel GECI that is introduced here is called CalBiT, and it is a Ca++ indicator based on the functional complementation of NanoBiT which shows a high dynamic change in response to Ca++ fluxes. Here, we use CalBiT for the detection of Ca++ fluctuations in cultured cells, including its ability for real-time imaging in living cells.

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