Reduce Background Noise Research Articles

Efficiency of synthetic excitation obtained by interference of ultrasonic waveforms for reducing background noise for laryngeotomee

Interference pattern of simulated ultrasonic waves using Matlab(free version R2010a) using the laws of acoustics has been used to get excitation in the audio frequency range. Preliminary experiments have been done using different high frequencies and the recordings have been done in Goldwave 5.1 version and then subsequent analysis have been done in Praat to analyze the beat frequency obtained by interfering two high frequency (above 15 kHz) waves. The output thus obtained has been then subjected to Hilbert Transform for envelope detection using Matlab(free version R2010a) to get the audio excitations. These audio excitations are further articulated by the glottal passage for speech synthesis for laryngeotomee or for producing alaryngeal speech. The results of simulation have been further utilised to fabricate a electronic circuit for generation of two continuous ultrasonic waves which are focussed to interfere inside the glottal tract, thereby producing a beat frequency in the audible range and reduce background noise. Index Terms: speech synthesis, ultrasonic waves, laryngeotomee Hilbert transform

Periodic power spectrum with applications in detection of latent periodicities in DNA sequences.

Periodic elements play important roles in genomic structures and functions, yet some complex periodic elements in genomes are difficult to detect by conventional methods such as digital signal processing and statistical analysis. We propose a periodic power spectrum (PPS) method for analyzing periodicities of DNA sequences. The PPS method employs periodic nucleotide distributions of DNA sequences and directly calculates power spectra at specific periodicities. The magnitude of a PPS reflects the strength of a signal on periodic positions. In comparison with Fourier transform, the PPS method avoids spectral leakage, and reduces background noise that appears high in Fourier power spectrum. Thus, the PPS method can effectively capture hidden periodicities in DNA sequences. Using a sliding window approach, the PPS method can precisely locate periodic regions in DNA sequences. We apply the PPS method for detection of hidden periodicities in different genome elements, including exons, microsatellite DNA sequences, and whole genomes. The results show that the PPS method can minimize the impact of spectral leakage and thus capture true hidden periodicities in genomes. In addition, performance tests indicate that the PPS method is more effective and efficient than a fast Fourier transform. The computational complexity of the PPS algorithm is [Formula: see text]. Therefore, the PPS method may have a broad range of applications in genomic analysis. The MATLAB programs for implementing the PPS method are available from MATLAB Central ( http://www.mathworks.com/matlabcentral/fileexchange/55298 ).

Coupling and control in coherently driven and asymmetrically synchronized hybrid electron-nuclear spin system

We study the coupling and control adaptation of a hybrid electron-nuclear spin system using the laser mediated proton beam in MeV energy regime. The asymmetric control mechanism is based on exact optimization of both: the measure of exchange interaction and anisotropy of the hyperfine interaction induced in the resonance with optimal channeled protons (CP) superfocused field, allowing manipulation over arbitrary localized spatial centers while addressing only the electron spin. Using highly precise and coherent proton channeling regime we have obtained efficient pulse shaping separator technique aimed for spatio-temporal engineering of quantum states, introducing a method for control of nuclear spins, which are coupled via anisotropic hyperfine interactions in isolated electron spin manifold, without radio wave (RW) pulses. The presented method can be efficiently implemented in synchronized spin networks with the purpose to facilitate preservation and efficient transfer of experimentally observed quantum particle states, contributing to the overall background noise reduction.

Reducing the risk of music-induced hearing loss from overuse of portable listening devices: understanding the problems and establishing strategies for improving awareness in adolescents.

Hearing loss from the overuse of portable listening devices (PLDs), such as MP3 players or iPods, is of great concern in the popular media. This review aims to discuss the current state of scientific knowledge about music-induced hearing loss from PLD use. This report evaluates the literature on the risk to hearing from PLD use, the individual and psychological factors that influence PLD usage, and strategies for reducing exposure to music through PLDs. Specific interventions are reviewed, and several recommendations for designing interventions and for individual intervention in clinical practice are presented. Clinical recommendations suggested include the “80–90 rule” and the use of isolator-style earphones to reduce background noise.

Rapid determination of sildenafil and its analogues in dietary supplements using gas chromatography–triple quadrupole mass spectrometry

Application of gas chromatography–triple quadrupole mass spectrometry for identification, confirmation and quantification of 6 phosphodiesterase-5 (PDE-5) inhibitors (sildenafil, dimethylsildenafil, homosildenafil, thiosildenafil, thiodimethylsildenafil and thiohomosildenafil) in dietary supplements was investigated. The MS was operated in multiple reaction monitoring mode, for better sensitivity and selectivity. In this manner, the method is adequate to reduce background noise with less interference from co-eluting compounds in the samples. Two different ionisation techniques, electron ionisation (EI) and chemical ionisation (CI), were studied and compared. The chromatographic separation was performed on a short 10m non-polar capillary column without any derivatisation step. This permitted fast analysis for all analogues with retention time less than 11min, for both techniques. Use of backflushing can aid method retention time reduction and improves column maintenance. Evaluation of method validation included limit of detection (LOD), lower limit of quantitation (LLOQ), linearity, precision and recovery were performed for both EI and CI techniques. The LOD obtained varied from 0.03 to 1.50μg/g and the LLOQ ranged from 0.10 to 5.00μg/g. Good calibration linearity was obtained for all analogues for both techniques, with correlation coefficients (r2) higher than 0.99. Mean recoveries of all analogues using CI show higher values (83.4–108.8%) than that of EI (61.9–91.1%). The intra- and inter-assay precisions were evaluated for all analogues at spiked concentration of 10μg/g and the relative standard deviation was less than 15% for both methods. These methods were then successfully applied to dietary supplement samples without prior derivatisation, confirming that the samples were adulterated with sildenafil and/or its analogues.

Miniature in vivo MEMS-based line-scanned dual-axis confocal microscope for point-of-care pathology.

There is a need for miniature optical-sectioning microscopes to enable in vivo interrogation of tissues as a real-time and noninvasive alternative to gold-standard histopathology. Such devices could have a transformative impact for the early detection of cancer as well as for guiding tumor-resection procedures. Miniature confocal microscopes have been developed by various researchers and corporations to enable optical sectioning of highly scattering tissues, all of which have necessitated various trade-offs in size, speed, depth selectivity, field of view, resolution, image contrast, and sensitivity. In this study, a miniature line-scanned (LS) dual-axis confocal (DAC) microscope, with a 12-mm diameter distal tip, has been developed for clinical point-of-care pathology. The dual-axis architecture has demonstrated an advantage over the conventional single-axis confocal configuration for reducing background noise from out-of-focus and multiply scattered light. The use of line scanning enables fast frame rates (16 frames/sec is demonstrated here, but faster rates are possible), which mitigates motion artifacts of a hand-held device during clinical use. We have developed a method to actively align the illumination and collection beams in a DAC microscope through the use of a pair of rotatable alignment mirrors. Incorporation of a custom objective lens, with a small form factor for in vivo clinical use, enables our device to achieve an optical-sectioning thickness and lateral resolution of 2.0 and 1.1 microns respectively. Validation measurements with reflective targets, as well as in vivo and ex vivo images of tissues, demonstrate the clinical potential of this high-speed optical-sectioning microscopy device.

Cochlear implant features and listening effort induction: measurement of the mental workload experienced during a word in noise recognition task

Cochlear implant features and listening effort induction: measurement of the mental workload experienced during a word in noise recognition task

Single-molecule detection at high concentrations with optical aperture nanoantennas.

Single-molecule detection has become an indispensable technology in life science, and medical research. In order to get meaningful information on many biological processes, single-molecule analysis is required in micro-molar concentrations. At such high concentrations, it is very challenging to isolate a single molecule with conventional diffraction-limited optics. Recently, optical aperture nanoantennas (OANs) have emerged as a powerful tool to enhance the single-molecule detection under a physiological environment. The OANs, which consist of nano-scale apertures on a metallic film, have the following unique properties: (1) nanoscale light confinement; (2) enhanced fluorescence emission; (3) tunable radiation pattern; (4) reduced background noise; and (5) massive parallel detection. This review presents the fundamentals, recent developments and future perspectives in this emerging field.

低次の誤差関数を用いた外積展開による背景雑音推定

This paper shows a new denoising algorithm based on the outer product expansion with lower norms for the background noise. We have proposed novel source separation methods using the outer product expansion with L1 norm minimization. Effectiveness of outer product expansions for artificial signals and an electromagnetic wave data was represented. However, the denoising performance is decreasing with an increasing of local signals. In this paper, we propose the outer product expansion with lower norms (0.1 ∼ 0.9). Simulation results show that the proposed method produces the accurate background noise reduction.

An enhance excavation equipments classification algorithm based on acoustic spectrum dynamic feature

Underground pipeline network surveillance system attracts increasingly attentions recently due to severe breakages caused by external excavation equipments in the mainland of China. In this paper, we study excavation equipments classification algorithm based on acoustic signal processing and machine learning algorithms. A cross-layer microphone array with four elements is designed to collect the acoustic database of representative excavation equipments on real construction sites. The generalized sidelobe canceller algorithm is employed for background noise reduction. The improved spectrum dynamic feature extraction algorithm is then implemented for the benchmark acoustic feature database construction of excavation equipments. To perform classification and background noise identification, the single hidden layer feedforward neural network is employed as the classifier. An improved algorithm based on the popular extreme learning machine (ELM) is proposed for classifier learning. The leave-one-out cross validation strategy is adopted for the regularization parameter optimization in ELM. Comprehensive experiments are conducted to test the effectiveness of the proposed algorithm. Comparisons with state-of-art classifiers and the Mel-frequency cepstrual coefficients acoustic features are also provided to demonstrate the superiority of our approach.

Rapid protocol for visualization of rust fungi structures using fluorochrome Uvitex 2B.

BackgroundHistological examination using fluorochromes is one of the standard methods for observation of microorganisms in tissues and other compartments. In the study of fungi, especially those that cannot be cultured in axenic media such as biotrophic fungi, histological examination of processes associated with the fungal growth, differentiation, infection and other cellular functions can lead to the better understanding of host-parasite interactions. Fluorescence microscopy coupled with Fluorochrome Uvitex 2B have been extensively utilized to study rust fungi structures and host-pathogen interactions. In this study, we report development of a rapid staining protocol of the rust fungus Puccinia triticina using fluorochrome Uvitex 2B. The newly developed rapid procedure was compared with a standard staining technique to observe in planta fungal infection structures development during the wheat—Puccinia triticina interaction.ResultsWhile significantly reducing the time for staining, the rapid protocol described here was equally efficient or better compared to standard procedure in detecting fungal infection structures using Uvitex 2B. In the rapid staining procedure, pre-heating of the stain increased efficiency to detect all the infection structures including haustoria with highly reduced background noise from plant tissue.ConclusionThis staining process described here is simple and quick. It can be completed in 4 h, which is of 6 times faster than the standard Uvitex 2B staining procedure.Electronic supplementary materialThe online version of this article (doi:10.1186/s13007-015-0096-0) contains supplementary material, which is available to authorized users.

Vibration sensor approaches for the sand detection in gas–sand two phases flow

The real-time measurement of solid phase in gas–sand flow is significant in the process of industrial production, especially for the economic benefit of natural gas production. Aiming to improve the existing limitations in solid particle detection of a gas conveying system, a vibration detection device for gas–solid flow has been developed and its evaluation test is conducted indoor. This paper illustrates the application of special wideband vibration sensor and sand mass flow computing method to monitor gas–sand flow in pipeline. In this work, a real-time computational formula for sand mass flow rate was firstly proposed. Both of the gas background noise reduction and the calibrated reference sand signals were considered in this formula. Besides, time–frequency analysis and characteristic sand frequency band digital filter methods were proposed to enhance the ability of sand detection in heavy gas flow background noise. The experimental investigation considered gas–sand flow both with sand content ranging from 0.0156vol.‰ to 0.1vol.‰ and sand size ranging from 45μm to 180μm. The results showed that there was a good correlation (less than ±8% uncertainties) between vibration energy and sand mass flow rate. Accordingly, the vibration technology provides a method for the detection of tiny particle size and dilute solid phase in solid–gas system, which lays the foundation for the quantitative particles detection in more complex multiphase flow.

Probing the Translation Dynamics of Ribosomes Using Zero-Mode Waveguides.

In order to coordinate the complex biochemical and structural feat of converting triple-nucleotide codons into their corresponding amino acids, the ribosome must physically manipulate numerous macromolecules including the mRNA, tRNAs, and numerous translation factors. The ribosome choreographs binding, dissociation, physical movements, and structural rearrangements so that they synergistically harness the energy from biochemical processes, including numerous GTP hydrolysis steps and peptide bond formation. Due to the dynamic and complex nature of translation, the large cast of ligands involved, and the large number of possible configurations, tracking the global time evolution or dynamics of the ribosome complex in translation has proven to be challenging for bulk methods. Conventional single-molecule fluorescence experiments on the other hand require low concentrations of fluorescent ligands to reduce background noise. The significantly reduced bimolecular association rates under those conditions limit the number of steps that can be observed within the time window available to a fluorophore. The advent of zero-mode waveguide (ZMW) technology has allowed the study of translation at near-physiological concentrations of labeled ligands, moving single-molecule fluorescence microscopy beyond focused model systems into studying the global dynamics of translation in realistic setups. This chapter reviews the recent works using the ZMW technology to dissect the mechanism of translation initiation and elongation in prokaryotes, including complex processes such as translational stalling and frameshifting. Given the success of the technology, similarly complex biological processes could be studied in near-physiological conditions with the controllability of conventional in vitro experiments.

Design of an experimental platform to investigate the effects of audible sounds on plant growth

An experimental platform was developed to investigate the effects of audible sound (20 Hz to 20 MHz) on plant growth promotion, which included a microcontroller-based embedded system for audible sound adjustment and analysis. The direct digital frequency synthesis (DDFS) method was used to generate various waveforms of sound in the platform. Soundproof glass and mufflers were used to reduce background noise. The developed system was tested on various plants, including hydroponic tomatoes, celery and mung bean. The testing results showed that the developed platform could produce pure tone and mixing audible sound with high stability and accuracy, make octave analysis of the sound under experimental environments, and the background noise in the testing chamber of the platform was lower than 55 dB(A) when the compression engine was working. The developed experimental platform has a great potential on facilitating scientific research on acoustic biology effects on plants and collecting real-time experimental data. Keywords: plant growth, background noise, acoustic biology effect, direct digital frequency synthesis, sound sensor DOI: 10.3965/j.ijabe.20150805.1556 Citation: Cai W M, Zhu S M, Wang N, He H N, Ying B H. Design of an experimental platform to investigate the effects of audible sounds on plant growth. Int J Agric & Biol Eng, 2015; 8(5): 162－169.

Rapid detection of multiple foodborne pathogens using a nanoparticle-functionalized multi-junction biosensor.

Real-time identification of multiple bacterial pathogens in food is urgently needed to ensure food safety. Although rapid and sensitive detection methods offering simplicity, accuracy, and multiplexity are highly desirable for industrial food applications, the development of a biosensor that meets all criteria remains a challenge. In this study, a single walled carbon nanotube- (SWCNT) based multi-junction sensor was designed for potential multiplexed detection of foodborne pathogens. Gold tungsten wires (Ø: 50 μm) coated with polyethylenimine (PEI) and SWCNTs were aligned to form a 2 × 2 junction array, functionalized with streptavidin and biotinylated antibodies specific for Escherichia coli K-12 and Staphylococcus aureus. Electric current (I) measurements in response to target binding events in pure serial diluted samples of E. coli and S. aureus at each junction within the 2 × 2 array were monitored to create calibration curves. An inverse correlation between I signals and bacterial concentrations was observed. Changes in I (∆I) were also calculated to reduce background noise and emphasize the SWCNT-based sensor's response to the biorecognition reactions between antibody and antigens. A linear regression was observed for both the E. coli and S. aureus functionalized array sensors, R(2)=0.978 and R(2)=0.992, in range of 10(2)-10(5)CFU/mL. The calibration curves were used to evaluate the sensor's multiplexing capabilities to detect E. coli and S. aureus in 10 µL and 100 µL batch microbial cocktail samples.Isignal responses exhibited similar measurement trends indicating that the developed SWCNT-based multi-junction biosensor has potential for sensitive, simple, and multiplexed applications.

Improvement of a Pound-Drever-Hall Technique to Measure Precisely the Free Spectral Range of a Fabry-Perot Etalon

We examine the principle of a modified Pound-Drever-Hall (PDH) technique to measure the free spectral range of a Fabry-Perot etalon (FPE). The FPE's periodic transmission of phase-modulated light allows us to adopt a sampling theorem to develop a new relationship for the PDH error signal. This leads us to find the key parameters governing the measurement accuracy: the phase modulation index ${\beta}$ and the FPE finesse. Without any additional complexity for background noise reduction, we achieve a measurement accuracy of 0.5 ppm. The improvement is mainly attributed to the wide-band phase modulation approaching ${\beta}=10$ , and partly to the use of both reflected and transmitted light from the FPE and good FPE finesse.

Direct optical nanoscopy with axially localized detection

Evanescent light excitation is widely used in super-resolution fluorescence microscopy to confine light and reduce background noise. Herein we propose a method of exploiting evanescent light in the context of emission. When a fluorophore is located in close proximity to a medium with a higher refractive index, its near-field component is converted into light that propagates beyond the critical angle. This so-called Supercritical Angle Fluorescence (SAF) can be captured using a hig-NA objective and used to determine the axial position of the fluorophore with nanometer precision. We introduce a new technique for 3D nanoscopy that combines direct STochastic Optical Reconstruction Microscopy (dSTORM) imaging with dedicated detection of SAF emission. We demonstrate that our approach of a Direct Optical Nanoscopy with Axially Localized Detection (DONALD) yields a typical isotropic 3D localization precision of 20 nm.

Predicting the intrusiveness of noise through sparse coding with auditory kernels

This paper presents a novel approach to predicting the intrusiveness of background noises in speech signals as it is perceived by human listeners. This problem is of particular interest in telephony, where the recently widened range of transmitted audio frequencies has increased the importance of appropriate background noise reduction strategies. Current approaches predict the average noise intrusiveness score that would be obtained in a subjective listening test by combining different signal features related to physical properties (e.g., signal energy, spectral distribution) or psychoacoustic estimations (e.g., loudness) of noise. The combination and/or implementation of such features requires expert knowledge or the availability of training data. We present a novel approach that is based on a model of efficient sound coding, using a sparse spike coding representation of noise. We show that the sparsity of these representations implicitly models several factors in the perception of noise, and yields predictions of noise intrusiveness scores that compare to or outperform traditional features, without the use of training data. Our evaluation datasets and used performance metrics are based on standardized methods for the evaluation of quality prediction models.

The treatment of tendon injury with electromagnetic fields evidenced by advanced ultrasound image processing

This article presents a novel modality for accelerating the repair of tendon and ligament lesions by means of a specifically designed electromagnetic field in an equine model. This novel therapeutic approach employs a delivery system that induces a specific electrical signal from an external magnetic field derived from Superconductive QUantum Interference Device (SQUID) measurements of injured vs. healthy tissue. Evaluation of this therapy technique is enabled by a proposed new technology described as Predictive Analytical Imagery (PAI™). This technique examines an ultrasound grayscale image and seeks to evaluate it by means of look-ahead predictive algorithms and digital signal processing. The net result is a significant reduction in background noise and the production of a high-resolution grayscale or digital image.

Sound source measurement by using a passive sound insulation and a statistical approach

This paper describes a measurement technique developed by the authors that allows carrying out acoustic measurements inside noisy environments reducing background noise effects. The proposed method is based on the integration of a traditional passive noise insulation system with a statistical approach. The latter is applied to signals picked up by usual sensors (microphones and accelerometers) equipping the passive sound insulation system. The statistical approach allows improving of the sound insulation given only by the passive sound insulation system at low frequency. The developed measurement technique has been validated by means of numerical simulations and measurements carried out inside a real noisy environment. For the case-studies here reported, an average improvement of about 10dB has been obtained in a frequency range up to about 250Hz. Considerations on the lower sound pressure level that can be measured by applying the proposed method and the measurement error related to its application are reported as well.