scholarly journals A High-Through Technique to Measure DNA Methylation

2010 ◽  
Vol 3 ◽  
pp. GEG.S5035 ◽  
Author(s):  
Zhiming Zhang ◽  
Jian Gao ◽  
Cheng Qin ◽  
Li Liu ◽  
Haijian Lin ◽  
...  
Keyword(s):  
Dna Methylation ◽  
High Efficiency ◽  
Simple Procedure ◽  
Point Mutations ◽  
Low Frequency ◽  
High Sensitivity ◽  
Snp Analysis ◽  
Allelic Series ◽  
Low Frequencies ◽  
Powerful Approach

MethyLight is a sodium-bisulfite-dependent, quantitative, fluorescence-based, real-time PCR strategy that is used to detect and quantify DNA methylation in genomic DNA. High-throughput MethyLight allows the rapid and sensitive detection of very low frequencies of hypermethylated alleles in populations of alternated individuals. The high sensitivity and specificity of MethyLight can be applied not only to make it uniquely suited disease clinical but also quantitatively assessed of these low-frequency methylation events. Owing to its full of advantages of simple procedure, high efficiency and high sensitivity, MethyLight provides a powerful approach for clinical examination, Gene expression analysis, SNP analysis and allele analysis. Coupled with other techniques, MethyLight can be used immediately in identifying allelic alterations in genes exhibiting expressions correlating with phenotypes, Locating an allelic series of induced point mutations in genes of interest. The development of this technique should considerably enhance our ability to rapidly and accurately generate epigenetic profiles of samples.

Low-frequency multiplex CARS microscopy with a high-repetition near-infrared supercontinuum laser

2021 ◽  
Author(s):  
Yusuke Arashida ◽  
Atsushi Taninaka ◽  
Takayuki Ochiai ◽  
Hiroyuki Mogi ◽  
Shoji YOSHIDA ◽  
...  
Keyword(s):  
Near Infrared ◽  
High Efficiency ◽  
Signal To Noise Ratio ◽  
Low Frequency ◽  
High Sensitivity ◽  
High Repetition ◽  
Spectrum Shaping ◽  
Crystal Phase Transition ◽  
Wavenumber Region ◽  
Anti Stokes

Abstract We have developed a multiplex Coherent anti-Stokes Raman scattering (CARS) microscope effective for low-wavenumber measurement by combining a high-repetition supercontinuum light source of 1064 nm and an infrared high-sensitivity InGaAs diode array. This system could observe the low-wavenumber region down to 55 cm-1 with high sensitivity. In addition, using spectrum shaping and spectrum modulation techniques, we simultaneously realized a wide bandwidth (<1800 cm-1), high wavenumber resolution (9 cm-1), high efficiency, and increasing signal to noise ratio by reducing the effect of the background shape in low-wavenumber region. Spatial variation of a sulfur crystal phase transition with metastable states was visualized.

scholarly journals Bioinspired Low-Frequency Material Characterisation

2012 ◽  
Vol 2012 ◽  
pp. 1-12 ◽  
Author(s):  
C. Hopper ◽  
S. Assous ◽  
P. B. Wilkinson ◽  
D. A. Gunn ◽  
P. D. Jackson ◽  
...  
Keyword(s):  
Sound Velocity ◽  
Medical Physics ◽  
Low Frequency ◽  
High Sensitivity ◽  
Prediction Errors ◽  
Low Frequencies ◽  
Longitudinal Sound Velocity ◽  
Velocity Prediction ◽  
Thickness Measurements

New-coded signals, transmitted by high-sensitivity broadband transducers in the 40–200 kHz range, allow subwavelength material discrimination and thickness determination of polypropylene, polyvinylchloride, and brass samples. Frequency domain spectra enable simultaneous measurement of material properties including longitudinal sound velocity and the attenuation constant as well as thickness measurements. Laboratory test measurements agree well with model results, with sound velocity prediction errors of less than 1%, and thickness discrimination of at least wavelength/15. The resolution of these measurements has only been matched in the past through methods that utilise higher frequencies. The ability to obtain the same resolution using low frequencies has many advantages, particularly when dealing with highly attenuating materials. This approach differs significantly from past biomimetic approaches where actual or simulated animal signals have been used and consequently has the potential for application in a range of fields where both improved penetration and high resolution are required, such as nondestructive testing and evaluation, geophysics, and medical physics.

Effects of Frequency on the Directional Auditory Sensitivity of Northern Saw-Whet Owls (Aegolius acadicus)

2021 ◽  
pp. 1-11
Author(s):  
Eileanor P. LaRocco ◽  
Glenn A. Proudfoot ◽  
Megan D. Gall
Keyword(s):  
Auditory Evoked Potentials ◽  
Transfer Functions ◽  
Low Frequency ◽  
High Sensitivity ◽  
Directional Hearing ◽  
Directional Sensitivity ◽  
Low Frequencies ◽  
Aegolius Acadicus ◽  
Spatial Locations ◽  
Prey Items

Many animals use sound as a medium for detecting or locating potential prey items or predation threats. Northern saw-whet owls (<i>Aegolius acadicus</i>) are particularly interesting in this regard, as they primarily rely on sound for hunting in darkness, but are also subject to predation pressure from larger raptors. We hypothesized that these opposing tasks should favor sensitivity to low-frequency sounds arriving from many locations (potential predators) and high-frequency sounds below the animal (ground-dwelling prey items). Furthermore, based on the morphology of the saw-whet owl skull and the head-related transfer functions of related species, we expected that the magnitude of changes in sensitivity across spatial locations would be greater for higher frequencies than low frequencies (i.e., more “directional” at high frequencies). We used auditory-evoked potentials to investigate the frequency-specific directional sensitivity of Northern saw-whet owls to acoustic signals. We found some support for our hypothesis, with smaller-magnitude changes in sensitivity across spatial locations at lower frequencies and larger-magnitude changes at higher frequencies. In general, owls were most sensitive to sounds originating in front of and above their heads, but at 8 kHz there was also an area of high sensitivity below the animals. Our results suggest that the directional hearing of saw-whet owls should allow for both predator and prey detection.

scholarly journals Testing the Annular Mode Autocorrelation Time Scale in Simple Atmospheric General Circulation Models

2008 ◽  
Vol 136 (4) ◽  
pp. 1523-1536 ◽  
Author(s):  
Edwin P. Gerber ◽  
Sergey Voronin ◽  
Lorenzo M. Polvani
Keyword(s):  
Time Scale ◽  
General Circulation ◽  
Simple Procedure ◽  
Low Frequency ◽  
General Circulation Models ◽  
Low Frequencies ◽  
Annular Mode ◽  
Fluctuation Dissipation ◽  
Low Frequency Variability ◽  
Autocorrelation Time

Abstract A new diagnostic for measuring the ability of atmospheric models to reproduce realistic low-frequency variability is introduced in the context of Held and Suarez’s 1994 proposal for comparing the dynamics of different general circulation models. A simple procedure to compute τ, the e-folding time scale of the annular mode autocorrelation function, is presented. This quantity concisely quantifies the strength of low-frequency variability in a model and is easy to compute in practice. The sensitivity of τ to model numerics is then studied for two dry primitive equation models driven with the Held–Suarez forcings: one pseudospectral and the other finite volume. For both models, τ is found to be unrealistically large when the horizontal resolutions are low, such as those that are often used in studies in which long integrations are needed to analyze model variability on low frequencies. More surprising is that it is found that, for the pseudospectral model, τ is particularly sensitive to vertical resolution, especially with a triangular truncation at wavenumber 42 (a very common resolution choice). At sufficiently high resolution, the annular mode autocorrelation time scale τ in both models appears to converge around values of 20–25 days, suggesting the existence of an intrinsic time scale at which the extratropical jet vacillates in the Held and Suarez system. The importance of τ for computing the correct response of a model to climate change is explicitly demonstrated by perturbing the pseudospectral model with simple torques. The amplitude of the model’s response to external forcing increases as τ increases, as suggested by the fluctuation–dissipation theorem.

scholarly journals Validation of the Point-EXACCT method in non-small cell lung carcinomas

1998 ◽  
Vol 44 (7) ◽  
pp. 1404-1409 ◽  
Author(s):  
Veerle A M C Somers ◽  
Darcy A Leimbach ◽  
Paul H M H Theunissen ◽  
James J Murtagh ◽  
Brian Holloway ◽  
...  
Keyword(s):  
Squamous Cell ◽  
Point Mutations ◽  
Low Frequency ◽  
High Sensitivity ◽  
Large Cell ◽  
Small Cell ◽  
Squamous Cell Carcinomas ◽  
Small Cell Lung ◽  
Lung Carcinomas ◽  
Highly Sensitive

Abstract K-ras point mutations are often detected in part of the lung carcinomas. For the validation of a highly sensitive and rapid assay for known point mutations, Point-EXACCT (Biochim Biophys Acta 1998; 1379:42–52), we analyzed 89 non-small cell lung carcinomas and compared the results with two sequencing methods. No point mutations were found with double-stranded sequencing. Single-stranded sequencing detected six patients positive for K-ras codon 12. When Point-EXACCT was used, K-ras codon 12 mutations were detected in 8 of 52 patients with squamous cell carcinomas, 10 of 29 patients with adenocarcinomas, and 3 of 8 patients with large cell carcinomas. The finding of K-ras mutations in squamous cell carcinomas is explained by the high sensitivity of the method. Therefore, Point-EXACCT may be applicable to detection of those alterations occurring at a low frequency among an excess of cells with wild-type DNA.

scholarly journals Hydrodynamic and Energy Capture Properties of a Cylindrical Triboelectric Nanogenerator for Ocean Buoy

2021 ◽  
Vol 11 (7) ◽  
pp. 3076
Author(s):  
Hengxu Liu ◽  
Feng Yan ◽  
Yeqing Jin ◽  
Weiqi Liu ◽  
Hailong Chen ◽  
...  
Keyword(s):  
High Efficiency ◽  
Low Frequency ◽  
Practical Significance ◽  
Triboelectric Nanogenerator ◽  
Low Frequencies ◽  
Energy Capture ◽  
Finite Element Software ◽  
Ocean Wave Energy ◽  
Electromagnetic Power ◽  
Power Generation Technology

It is rather challenging to collect ocean wave energy at high efficiency because of its ultra-low frequencies and variable amplitudes. Triboelectric Nanogenerator (TENG) technology is more suitable for harvesting low-frequency than electromagnetic power generation technology. In this work, we designed a built-in cylindrical Triboelectric Nanogenerator (C-TENG) installed inside the ocean buoy (BUOY-41). The hydrodynamic properties of the C-TENG are consistent with the ocean buoy, which are calculated by CFD software (Star-CCM+). The Energy Capture Properties of the C-TENG are established by the finite element software (COMSOL). The C-TENG has high power density (30 mW/m2) and can meet the power demand of the ocean buoy (10 mW). The implementation of the present work is of great academic value and practical significance for the development of efficient marine renewable energy conversion technology, enhancement of marine equipment energy replenishment, enrichment of hydrodynamic theories and revealing of the complex mechanisms.

scholarly journals The Low frequency Space Array (LFSA)

1988 ◽  
Vol 129 ◽  
pp. 459-460
Author(s):  
K. W. Weiler ◽  
B. K. Dennison ◽  
K. J. Johnston ◽  
R. S. Simon ◽  
J. H. Spencer ◽  
...  
Keyword(s):  
High Resolution ◽  
Milky Way ◽  
Low Frequency ◽  
High Sensitivity ◽  
Electromagnetic Spectrum ◽  
Low Frequencies ◽  
Frequency Space ◽  
Physical Limit ◽  
Path Lengths ◽  
Fundamental Physical

At the lowest radio frequencies (≤30 MHz), the Earth's ionosphere transmits poorly or not at all. This relatively unexplored region of the electromagnetic spectrum is thus an area where high resolution, high sensitivity observations can open a new window for astronomical investigations. Also, extending observations down to very low frequencies brings astronomy to a fundamental physical limit where the Milky Way becomes optically thick over relatively short path lengths due to diffuse free-free absorption.

scholarly journals Properties and magnetic origins of solar S-bursts

2019 ◽  
Vol 622 ◽  
pp. A204 ◽  
Author(s):  
Brendan P. Clarke ◽  
Diana E. Morosan ◽  
Peter T. Gallagher ◽  
Vladimir V. Dorovskyy ◽  
Alexander A. Konovalenko ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Solar Activity ◽  
Solar Radio ◽  
Low Frequency ◽  
High Sensitivity ◽  
Coronal Magnetic Field ◽  
Solar Radio Emission ◽  
Radio Bursts ◽  
Burst Source ◽  
Low Frequencies

Context. Solar activity is often accompanied by solar radio emission, consisting of numerous types of solar radio bursts. At low frequencies (<100 MHz) radio bursts with short durations of milliseconds, such as solar S-bursts, have been identified. To date, their origin and many of their characteristics remain unclear. Aims. We report observations from the Ukrainian T-shaped Radio telescope, (UTR-2), and the LOw Frequency ARray (LOFAR) which give us new insight into their nature. Methods. Over 3000 S-bursts were observed on 9 July 2013 at frequencies of 17.4–83.1 MHz during a period of low solar activity. Leading models of S-burst generation were tested by analysing the spectral properties of S-bursts and estimating coronal magnetic field strengths. Results. S-bursts were found to have short durations of 0.5–0.9 s. Multiple instruments were used to measure the dependence of drift rate on frequency which is represented by a power law with an index of 1.57. For the first time, we show a linear relation between instantaneous bandwidth and frequency over a wide frequency band. The flux calibration and high sensitivity of UTR-2 enabled measurements of their fluxes, which yielded 11 ± 3 solar flux units (1 SFU ≡ 104 Jy). The source particle velocities of S-bursts were found to be ∼0.07 c. S-burst source heights were found to range from 1.3 R⊙ to 2 R⊙. Furthermore, a contemporary theoretical model of S-burst generation was used to conduct remote sensing of the coronal magnetic field at these heights which yielded values of 0.9–5.8 G. Within error, these values are comparable to those predicted by various relations between magnetic field strength and height in the corona.

DEDICATED INSTRUMENTATION FOR HIGH SENSITIVITY, LOW FREQUENCY NOISE MEASUREMENT SYSTEMS

2004 ◽  
Vol 04 (02) ◽  
pp. L385-L402 ◽  
Author(s):  
C. CIOFI ◽  
G. GIUSI ◽  
G. SCANDURRA ◽  
B. NERI
Keyword(s):  
Background Noise ◽  
Flicker Noise ◽  
Low Frequency ◽  
High Sensitivity ◽  
Design Guidelines ◽  
Low Noise ◽  
Frequency Noise ◽  
Low Frequency Noise ◽  
Low Frequencies ◽  
Noise Measurements

Low Frequency Noise Measurements (LFNM) can be used as very sensitive tool for the characterization of the quality and the reliability of electron devices. However, especially in those cases in which the frequency range of interest extends below 1 Hz, instrumentation with an acceptable low level of background noise is not easily found on the market. In fact, at very low frequencies, the flicker noise introduced by the electronic components which make up the instrumentation becomes predominant and several interesting phenomena which could be detected by means of LFNM may result completely hidden in the background noise. This consideration is not limited to the case of input preamplifiers but does extend to any piece of instrumentation that contributes to the LFNM systems, and in particular to the power supplies used for biasing the Device Under Test. During the last few years, our research groups have been strongly involved in the design of very low noise instrumentation for application in the field of LFNM. In this work we report the main results which we have obtained together with a discussion of the design guidelines that have allowed us, in a few cases, to reach noise levels not to be equalled by any instrumentation available on the market.

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