WorldWideScience

Sample records for acoustic 4f imaging

  1. Acoustical Imaging

    CERN Document Server

    Litniewski, Jerzy; Kujawska, Tamara; 31st International Symposium on Acoustical Imaging

    2012-01-01

    The International Symposium on Acoustical Imaging is a unique forum for advanced research, covering new technologies, developments, methods and theories in all areas of acoustics. This interdisciplinary Symposium has been taking place continuously since 1968. In the course of the years the proceedings volumes in the Acoustical Imaging Series have become a reference for cutting-edge research in the field. In 2011 the 31st International Symposium on Acoustical Imaging was held in Warsaw, Poland, April 10-13. Offering both a broad perspective on the state-of-the-art as well as  in-depth research contributions by the specialists in the field, this Volume 31 in the Series contains an excellent collection of papers in six major categories: Biological and Medical Imaging Physics and Mathematics of Acoustical Imaging Acoustic Microscopy Transducers and Arrays Nondestructive Evaluation and Industrial Applications Underwater Imaging

  2. Acoustical Imaging

    CERN Document Server

    Akiyama, Iwaki

    2009-01-01

    The 29th International Symposium on Acoustical Imaging was held in Shonan Village, Kanagawa, Japan, April 15-18, 2007. This interdisciplinary Symposium has been taking place every two years since 1968 and forms a unique forum for advanced research, covering new technologies, developments, methods and theories in all areas of acoustics. In the course of the years the volumes in the Acoustical Imaging Series have developed and become well-known and appreciated reference works. Offering both a broad perspective on the state-of-the-art in the field as well as an in-depth look at its leading edge research, this Volume 29 in the Series contains again an excellent collection of seventy papers presented in nine major categories: Strain Imaging Biological and Medical Applications Acoustic Microscopy Non-Destructive Evaluation and Industrial Applications Components and Systems Geophysics and Underwater Imaging Physics and Mathematics Medical Image Analysis FDTD method and Other Numerical Simulations Audience Researcher...

  3. 4F-based optical phase imaging system

    DEFF Research Database (Denmark)

    2013-01-01

    The invention relates to 4F-based optical phase imaging system and in particular to reconstructing quantitative phase information of an object when using such systems. The invention applies a two-dimensional, complex spatial light modulator (SLM) to impress a complex spatial synthesized modulation...... in addition to the complex spatial modulation impressed by the object. This SLM is arranged so that the synthesized modulation is superimposed with the object modulation and is thus placed at an input plane to the phase imaging system. By evaluating output images from the phase imaging system, the synthesized...... modulation is selected to optimize parameters in the output image which improves the reconstruction of qualitative and quantitative object phase information from the resulting output images....

  4. Acoustic imaging system

    Science.gov (United States)

    Smith, Richard W.

    1979-01-01

    An acoustic imaging system for displaying an object viewed by a moving array of transducers as the array is pivoted about a fixed point within a given plane. A plurality of transducers are fixedly positioned and equally spaced within a laterally extending array and operatively directed to transmit and receive acoustic signals along substantially parallel transmission paths. The transducers are sequentially activated along the array to transmit and receive acoustic signals according to a preestablished sequence. Means are provided for generating output voltages for each reception of an acoustic signal, corresponding to the coordinate position of the object viewed as the array is pivoted. Receptions from each of the transducers are presented on the same display at coordinates corresponding to the actual position of the object viewed to form a plane view of the object scanned.

  5. 30th International Acoustical Imaging Symposium

    CERN Document Server

    Jones, Joie; Lee, Hua

    2011-01-01

    The International Symposium on Acoustical Imaging is a unique forum for advanced research, covering new technologies, developments, methods and theories in all areas of acoustics. This interdisciplinary Symposium has been taking place every two years since 1968. In the course of the years the proceedings volumes in the Acoustical Imaging Series have become a reference for cutting-edge research in the field. In 2009 the 30th International Symposium on Acoustical Imaging was held in Monterey, CA, USA, March 1-4. Offering both a broad perspective on the state-of-the-art as well as  in-depth research contributions by the specialists in the field, this Volume 30 in the Series contains an excellent collection of forty three papers presented in five major categories: Biomedical Imaging Acoustic Microscopy Non-Destructive Evaluation Systems Analysis Signal Analysis and Image Processing Audience Researchers in medical imaging and biomedical instrumentation experts.

  6. Homotopy Based Reconstruction from Acoustic Images

    DEFF Research Database (Denmark)

    Sharma, Ojaswa

    with known geometry. The results of the methods shown here can be used to gain objective knowledge about the reconstructed features. It is envisioned that due to the generic nature of the algorithms developed in this research, domains other than fisheries research can benefit from the reconstruction...... are reconstruction from an organised set of linear cross sections and reconstruction from an arbitrary set of linear cross sections. The first problem is looked upon in the context of acoustic signals wherein the cross sections show a definite geometric arrangement. A reconstruction in this case can take advantage...... of the inherent arrangement. The problem of reconstruction from arbitrary cross sections is a generic problem and is also shown to be solved here using the mathematical tool of continuous deformations. As part of a complete processing, segmentation using level set methods is explored for acoustic images and fast...

  7. 28th International Acoustical Imaging Symposium

    CERN Document Server

    André, Michael P; Andre, Michael; Arnold, Walter; Bamber, Jeff; Burov, Valentin; Chubachi, Noriyoshi; Erikson, Kenneth; Ermert, Helmut; Fink, Mathias; Gan, Woon S; Granz, Bernd; Greenleaf, James; Hu, Jiankai; Jones, Joie P; Khuri-Yakub, Pierre; Laugier, Pascal; Lee, Hua; Lees, Sidney; Levin, Vadim M; Maev, Roman; Masotti, Leonardo; Nowicki, Andrzej; O’Brien, William; Prasad, Manika; Rafter, Patrick; Rouseff, Daniel; Thijssen, Johan; Tittmann, Bernard; Tortoli, Piero; Steen, Anton; Waag, Robert; Wells, Peter; Acoustical Imaging

    2007-01-01

    The International Acoustical Imaging Symposium has been held continuously since 1968 as a unique forum for advanced research, promoting the sharing of technology, developments, methods and theory among all areas of acoustics. The interdisciplinary nature of the Symposium and the wide international participation are two of its main strengths. Scientists from around the world present their papers in an informal environment conducive to lively discussion and cross-fertilization. The fact that a loyal community of scientists has supported this Series since 1968 is evidence of its impact on the field. The Symposium Series continues to thrive in a busy calendar of scientific meetings without the infrastructure of a professional society. It does so because those who attend and those who rely on the Proceedings as a well-known reference work acknowledge its value. This Volume 28 of the Proceedings likewise contains an excellent collection of papers presented in six major categories, offering both a broad perspective ...

  8. Nonlinear ultrasound imaging of nanoscale acoustic biomolecules

    Science.gov (United States)

    Maresca, David; Lakshmanan, Anupama; Lee-Gosselin, Audrey; Melis, Johan M.; Ni, Yu-Li; Bourdeau, Raymond W.; Kochmann, Dennis M.; Shapiro, Mikhail G.

    2017-02-01

    Ultrasound imaging is widely used to probe the mechanical structure of tissues and visualize blood flow. However, the ability of ultrasound to observe specific molecular and cellular signals is limited. Recently, a unique class of gas-filled protein nanostructures called gas vesicles (GVs) was introduced as nanoscale (˜250 nm) contrast agents for ultrasound, accompanied by the possibilities of genetic engineering, imaging of targets outside the vasculature and monitoring of cellular signals such as gene expression. These possibilities would be aided by methods to discriminate GV-generated ultrasound signals from anatomical background. Here, we show that the nonlinear response of engineered GVs to acoustic pressure enables selective imaging of these nanostructures using a tailored amplitude modulation strategy. Finite element modeling predicted a strongly nonlinear mechanical deformation and acoustic response to ultrasound in engineered GVs. This response was confirmed with ultrasound measurements in the range of 10 to 25 MHz. An amplitude modulation pulse sequence based on this nonlinear response allows engineered GVs to be distinguished from linear scatterers and other GV types with a contrast ratio greater than 11.5 dB. We demonstrate the effectiveness of this nonlinear imaging strategy in vitro, in cellulo, and in vivo.

  9. Magneto-acoustic imaging by continuous-wave excitation.

    Science.gov (United States)

    Shunqi, Zhang; Zhou, Xiaoqing; Tao, Yin; Zhipeng, Liu

    2017-04-01

    The electrical characteristics of tissue yield valuable information for early diagnosis of pathological changes. Magneto-acoustic imaging is a functional approach for imaging of electrical conductivity. This study proposes a continuous-wave magneto-acoustic imaging method. A kHz-range continuous signal with an amplitude range of several volts is used to excite the magneto-acoustic signal and improve the signal-to-noise ratio. The magneto-acoustic signal amplitude and phase are measured to locate the acoustic source via lock-in technology. An optimisation algorithm incorporating nonlinear equations is used to reconstruct the magneto-acoustic source distribution based on the measured amplitude and phase at various frequencies. Validation simulations and experiments were performed in pork samples. The experimental and simulation results agreed well. While the excitation current was reduced to 10 mA, the acoustic signal magnitude increased up to 10-7 Pa. Experimental reconstruction of the pork tissue showed that the image resolution reached mm levels when the excitation signal was in the kHz range. The signal-to-noise ratio of the detected magneto-acoustic signal was improved by more than 25 dB at 5 kHz when compared to classical 1 MHz pulse excitation. The results reported here will aid further research into magneto-acoustic generation mechanisms and internal tissue conductivity imaging.

  10. Transthoracic Cardiac Acoustic Radiation Force Impulse Imaging

    Science.gov (United States)

    Bradway, David Pierson

    This dissertation investigates the feasibility of a real-time transthoracic Acoustic Radiation Force Impulse (ARFI) imaging system to measure myocardial function non-invasively in clinical setting. Heart failure is an important cardiovascular disease and contributes to the leading cause of death for developed countries. Patients exhibiting heart failure with a low left ventricular ejection fraction (LVEF) can often be identified by clinicians, but patients with preserved LVEF might be undetected if they do not exhibit other signs and symptoms of heart failure. These cases motivate development of transthoracic ARFI imaging to aid the early diagnosis of the structural and functional heart abnormalities leading to heart failure. M-Mode ARFI imaging utilizes ultrasonic radiation force to displace tissue several micrometers in the direction of wave propagation. Conventional ultrasound tracks the response of the tissue to the force. This measurement is repeated rapidly at a location through the cardiac cycle, measuring timing and relative changes in myocardial stiffness. ARFI imaging was previously shown capable of measuring myocardial properties and function via invasive open-chest and intracardiac approaches. The prototype imaging system described in this dissertation is capable of rapid acquisition, processing, and display of ARFI images and shear wave elasticity imaging (SWEI) movies. Also presented is a rigorous safety analysis, including finite element method (FEM) simulations of tissue heating, hydrophone intensity and mechanical index (MI) measurements, and thermocouple transducer face heating measurements. For the pulse sequences used in later animal and clinical studies, results from the safety analysis indicates that transthoracic ARFI imaging can be safely applied at rates and levels realizable on the prototype ARFI imaging system. Preliminary data are presented from in vivo trials studying changes in myocardial stiffness occurring under normal and abnormal

  11. Laser-induced acoustic imaging of underground objects

    Science.gov (United States)

    Li, Wen; DiMarzio, Charles A.; McKnight, Stephen W.; Sauermann, Gerhard O.; Miller, Eric L.

    1999-02-01

    This paper introduces a new demining technique based on the photo-acoustic interaction, together with results from photo- acoustic experiments. We have buried different types of targets (metal, rubber and plastic) in different media (sand, soil and water) and imaged them by measuring reflection of acoustic waves generated by irradiation with a CO2 laser. Research has been focused on the signal acquisition and signal processing. A deconvolution method using Wiener filters is utilized in data processing. Using a uniform spatial distribution of laser pulses at the ground's surface, we obtained 3D images of buried objects. The images give us a clear representation of the shapes of the underground objects. The quality of the images depends on the mismatch of acoustic impedance of the buried objects, the bandwidth and center frequency of the acoustic sensors and the selection of filter functions.

  12. Optimization of a Biometric System Based on Acoustic Images

    Directory of Open Access Journals (Sweden)

    Alberto Izquierdo Fuente

    2014-01-01

    Full Text Available On the basis of an acoustic biometric system that captures 16 acoustic images of a person for 4 frequencies and 4 positions, a study was carried out to improve the performance of the system. On a first stage, an analysis to determine which images provide more information to the system was carried out showing that a set of 12 images allows the system to obtain results that are equivalent to using all of the 16 images. Finally, optimization techniques were used to obtain the set of weights associated with each acoustic image that maximizes the performance of the biometric system. These results improve significantly the performance of the preliminary system, while reducing the time of acquisition and computational burden, since the number of acoustic images was reduced.

  13. Optimization of a Biometric System Based on Acoustic Images

    Science.gov (United States)

    Izquierdo Fuente, Alberto; Del Val Puente, Lara; Villacorta Calvo, Juan J.; Raboso Mateos, Mariano

    2014-01-01

    On the basis of an acoustic biometric system that captures 16 acoustic images of a person for 4 frequencies and 4 positions, a study was carried out to improve the performance of the system. On a first stage, an analysis to determine which images provide more information to the system was carried out showing that a set of 12 images allows the system to obtain results that are equivalent to using all of the 16 images. Finally, optimization techniques were used to obtain the set of weights associated with each acoustic image that maximizes the performance of the biometric system. These results improve significantly the performance of the preliminary system, while reducing the time of acquisition and computational burden, since the number of acoustic images was reduced. PMID:24616643

  14. Acoustic-noise-optimized diffusion-weighted imaging.

    Science.gov (United States)

    Ott, Martin; Blaimer, Martin; Grodzki, David M; Breuer, Felix A; Roesch, Julie; Dörfler, Arnd; Heismann, Björn; Jakob, Peter M

    2015-12-01

    This work was aimed at reducing acoustic noise in diffusion-weighted MR imaging (DWI) that might reach acoustic noise levels of over 100 dB(A) in clinical practice. A diffusion-weighted readout-segmented echo-planar imaging (EPI) sequence was optimized for acoustic noise by utilizing small readout segment widths to obtain low gradient slew rates and amplitudes instead of faster k-space coverage. In addition, all other gradients were optimized for low slew rates. Volunteer and patient imaging experiments were conducted to demonstrate the feasibility of the method. Acoustic noise measurements were performed and analyzed for four different DWI measurement protocols at 1.5T and 3T. An acoustic noise reduction of up to 20 dB(A) was achieved, which corresponds to a fourfold reduction in acoustic perception. The image quality was preserved at the level of a standard single-shot (ss)-EPI sequence, with a 27-54% increase in scan time. The diffusion-weighted imaging technique proposed in this study allowed a substantial reduction in the level of acoustic noise compared to standard single-shot diffusion-weighted EPI. This is expected to afford considerably more patient comfort, but a larger study would be necessary to fully characterize the subjective changes in patient experience.

  15. Near-field acoustic imaging based on Laplacian sparsity

    DEFF Research Database (Denmark)

    Fernandez Grande, Efren; Daudet, Laurent

    2016-01-01

    We present a sound source identification method for near-field acoustic imaging of extended sources. The methodology is based on a wave superposition method (or equivalent source method) that promotes solutions with sparse higher order spatial derivatives. Instead of promoting direct sparsity......, and the validity of the wave extrapolation used for the reconstruction is examined. It is shown that this methodology can overcome conventional limits of spatial sampling, and is therefore valid for wide-band acoustic imaging of extended sources....

  16. Interpreting underwater acoustic images of the upper ocean boundary layer

    Energy Technology Data Exchange (ETDEWEB)

    Ulloa, Marco J [Departamento de Fisica, Centro Universitario de Ciencias Exactas e IngenierIas, Universidad de Guadalajara, Avenida Revolucion 1500, Sector Reforma, 44420 Guadalajara, Jal. (Mexico)

    2007-03-15

    A challenging task in physical studies of the upper ocean using underwater sound is the interpretation of high-resolution acoustic images. This paper covers a number of basic concepts necessary for undergraduate and postgraduate students to identify the most distinctive features of the images, providing a link with the acoustic signatures of physical processes occurring simultaneously beneath the surface of the sea. Sonars are so sensitive that they detected a new acoustic signature at the breaking of surface gravity waves in deep water, which resembles oblique motion-like vortices.

  17. Vibro-acoustic Imaging at the Breazeale Reactor

    Energy Technology Data Exchange (ETDEWEB)

    Smith, James Arthur [Idaho National Lab. (INL), Idaho Falls, ID (United States); Jewell, James Keith [Idaho National Lab. (INL), Idaho Falls, ID (United States); Lee, James Edwin [Idaho National Lab. (INL), Idaho Falls, ID (United States)

    2016-09-01

    The INL is developing Vibro-acoustic imaging technology to characterize microstructure in fuels and materials in spent fuel pools and within reactor vessels. A vibro-acoustic development laboratory has been established at the INL. The progress in developing the vibro-acoustic technology at the INL is the focus of this report. A successful technology demonstration was performed in a working TRIGA research reactor. Vibro-acoustic imaging was performed in the reactor pool of the Breazeale reactor in late September of 2015. A confocal transducer driven at a nominal 3 MHz was used to collect the 60 kHz differential beat frequency induced in a spent TRIGA fuel rod and empty gamma tube located in the main reactor water pool. Data was collected and analyzed with the INLDAS data acquisition software using a short time Fourier transform.

  18. Imaging acoustic sources moving at high-speed

    Science.gov (United States)

    Bodony, Daniel; Papanicolaou, George

    2006-11-01

    In the quantification of the noise radiated by a turbulent flow the source motion is important. It is well known that moving acoustic sources radiate sound preferrentially in the direction of motion in a phenomenon termed `convective amplification.' Modern acoustic theories have utilized this behavior in their predictions. In the inverse problem the imaging of noise sources, by techniques such as beam forming, the source motion is not explicitly taken into account. In this talk we consider the imaging of acoustic sources moving at speeds on the order of the the ambient speed of sound, as typical of high-speed jets, for which the D"oppler shift approximation is not appropriate. An analysis will be presented that can be used to estimate the source motion based on the radiated acoustic field.

  19. Synthetic Aperture Acoustic Imaging for Roadside Detection of Solid Objects

    Science.gov (United States)

    2014-11-20

    Testing I I I I Cinderblock Foam block Isometric and translucent view of the weighted foam block . .-.-; Weighted foam block Figure 2.3... concrete block (CB, Fig. 2.4). Conven- tional methods for identifying targets in a radar or acoustic imaging system (also known as Automatic Target...and curb, or than the grass-covered hill beyond the sidewalk. However, there is a strong acoustic return from a seam in the sidewalk concrete that runs

  20. Quantitative Determination of Lateral Mode Dispersion in Film Bulk Acoustic Resonators through Laser Acoustic Imaging

    Energy Technology Data Exchange (ETDEWEB)

    Ken Telschow; John D. Larson III

    2006-10-01

    Film Bulk Acoustic Resonators are useful for many signal processing applications. Detailed knowledge of their operation properties are needed to optimize their design for specific applications. The finite size of these resonators precludes their use in single acoustic modes; rather, multiple wave modes, such as, lateral wave modes are always excited concurrently. In order to determine the contributions of these modes, we have been using a newly developed full-field laser acoustic imaging approach to directly measure their amplitude and phase throughout the resonator. This paper describes new results comparing modeling of both elastic and piezoelectric effects in the active material with imaging measurement of all excited modes. Fourier transformation of the acoustic amplitude and phase displacement images provides a quantitative determination of excited mode amplitude and wavenumber at any frequency. Images combined at several frequencies form a direct visualization of lateral mode excitation and dispersion for the device under test allowing mode identification and comparison with predicted operational properties. Discussion and analysis are presented for modes near the first longitudinal thickness resonance (~900 MHz) in an AlN thin film resonator. Plate wave modeling, taking account of material crystalline orientation, elastic and piezoelectric properties and overlayer metallic films, will be discussed in relation to direct image measurements.

  1. Performance Evaluation of a Biometric System Based on Acoustic Images

    Directory of Open Access Journals (Sweden)

    Juan J. Villacorta

    2011-10-01

    Full Text Available An acoustic electronic scanning array for acquiring images from a person using a biometric application is developed. Based on pulse-echo techniques, multifrequency acoustic images are obtained for a set of positions of a person (front, front with arms outstretched, back and side. Two Uniform Linear Arrays (ULA with 15 l/2-equispaced sensors have been employed, using different spatial apertures in order to reduce sidelobe levels. Working frequencies have been designed on the basis of the main lobe width, the grating lobe levels and the frequency responses of people and sensors. For a case-study with 10 people, the acoustic profiles, formed by all images acquired, are evaluated and compared in a mean square error sense. Finally, system performance, using False Match Rate (FMR/False Non-Match Rate (FNMR parameters and the Receiver Operating Characteristic (ROC curve, is evaluated. On the basis of the obtained results, this system could be used for biometric applications.

  2. Imaging of Acoustic Waves in Piezoelectric Ceramics by Coulomb Coupling

    Science.gov (United States)

    Habib, Anowarul; Shelke, Amit; Pluta, Mieczyslaw; Kundu, Tribikram; Pietsch, Ullrich; Grill, Wolfgang

    2012-07-01

    The transport properties of bulk and guided acoustic waves travelling in a lead zirconate titanate (PZT) disc, originally manufactured to serve as ultrasonic transducer, have been monitored by scanned Coulomb coupling. The images are recorded by excitation and detection of ultrasound with local electric field probes via piezoelectric coupling. A narrow pulse has been used for excitation. Broadband coupling is achieved since neither mechanical nor electrical resonances are involved. The velocities of the traveling acoustic waves determined from the images are compared with characteristic velocities calculated from material properties listed by the manufacturer of the PZT plate.

  3. Acoustic Angiography: A New Imaging Modality for Assessing Microvasculature Architecture

    Directory of Open Access Journals (Sweden)

    Ryan C. Gessner

    2013-01-01

    Full Text Available The purpose of this paper is to provide the biomedical imaging community with details of a new high resolution contrast imaging approach referred to as “acoustic angiography.” Through the use of dual-frequency ultrasound transducer technology, images acquired with this approach possess both high resolution and a high contrast-to-tissue ratio, which enables the visualization of microvascular architecture without significant contribution from background tissues. Additionally, volumetric vessel-tissue integration can be visualized by using b-mode overlays acquired with the same probe. We present a brief technical overview of how the images are acquired, followed by several examples of images of both healthy and diseased tissue volumes. 3D images from alternate modalities often used in preclinical imaging, contrast-enhanced micro-CT and photoacoustics, are also included to provide a perspective on how acoustic angiography has qualitatively similar capabilities to these other techniques. These preliminary images provide visually compelling evidence to suggest that acoustic angiography may serve as a powerful new tool in preclinical and future clinical imaging.

  4. Systematic Error of Acoustic Particle Image Velocimetry and Its Correction

    Directory of Open Access Journals (Sweden)

    Mickiewicz Witold

    2014-08-01

    Full Text Available Particle Image Velocimetry is getting more and more often the method of choice not only for visualization of turbulent mass flows in fluid mechanics, but also in linear and non-linear acoustics for non-intrusive visualization of acoustic particle velocity. Particle Image Velocimetry with low sampling rate (about 15Hz can be applied to visualize the acoustic field using the acquisition synchronized to the excitation signal. Such phase-locked PIV technique is described and used in experiments presented in the paper. The main goal of research was to propose a model of PIV systematic error due to non-zero time interval between acquisitions of two images of the examined sound field seeded with tracer particles, what affects the measurement of complex acoustic signals. Usefulness of the presented model is confirmed experimentally. The correction procedure, based on the proposed model, applied to measurement data increases the accuracy of acoustic particle velocity field visualization and creates new possibilities in observation of sound fields excited with multi-tonal or band-limited noise signals.

  5. Combination of acoustical radiosity and the image source method

    DEFF Research Database (Denmark)

    Koutsouris, Georgios I; Brunskog, Jonas; Jeong, Cheol-Ho

    2013-01-01

    A combined model for room acoustic predictions is developed, aiming to treat both diffuse and specular reflections in a unified way. Two established methods are incorporated: acoustical radiosity, accounting for the diffuse part, and the image source method, accounting for the specular part....... The model is based on conservation of acoustical energy. Losses are taken into account by the energy absorption coefficient, and the diffuse reflections are controlled via the scattering coefficient, which defines the portion of energy that has been diffusely reflected. The way the model is formulated...... allows for a dynamic control of the image source production, so that no fixed maximum reflection order is required. The model is optimized for energy impulse response predictions in arbitrary polyhedral rooms. The predictions are validated by comparison with published measured data for a real music...

  6. Monitoring of rapid sand filters using an acoustic imaging technique

    NARCIS (Netherlands)

    Allouche, N.; Simons, D.G.; Rietveld, L.C.

    2012-01-01

    A novel instrument is developed to acoustically image sand filters used for water treatment and monitor their performance. The instrument consists of an omnidirectional transmitter that generates a chirp with a frequency range between 10 and 110 kHz, and an array of hydrophones. The instrument was

  7. Near-field acoustic imaging based on Laplacian sparsity

    DEFF Research Database (Denmark)

    Fernandez Grande, Efren; Daudet, Laurent

    2016-01-01

    We present a sound source identification method for near-field acoustic imaging of extended sources. The methodology is based on a wave superposition method (or equivalent source method) that promotes solutions with sparse higher order spatial derivatives. Instead of promoting direct sparsity...

  8. Acoustic property measurements in a photoacoustic imager

    NARCIS (Netherlands)

    Willemink, Rene; Manohar, Srirang; Slump, Cornelis H.; van der Heijden, Ferdinand; van Leeuwen, Ton; Depeursinge, C.D.

    2007-01-01

    Photoacoustics is a hybrid imaging technique that combines the contrast available to optical imaging with the resolution that is possessed by ultrasound imaging. The technique is based on generating ultrasound from absorbing structures in tissue using pulsed light. In photoacoustic (PA) computerized

  9. Polymer Optical Fibre Sensors for Endoscopic Opto-Acoustic Imaging

    DEFF Research Database (Denmark)

    Broadway, Christian; Gallego, Daniel; Woyessa, Getinet

    2015-01-01

    Opto-acoustic imaging (OAI) shows particular promise for in-vivo biomedical diagnostics. Its applications include cardiovascular, gastrointestinal and urogenital systems imaging. Opto-acoustic endoscopy (OAE) allows the imaging of body parts through cavities permitting entry. The critical parameter...... is the physical size of the device, allowing compatibility with current technology, while governing flexibility of the distal end of the endoscope based on the needs of the sensor. Polymer optical fibre (POF) presents a novel approach for endoscopic applications and has been positively discussed and compared...... in existing publications. A great advantage can be obtained for endoscopy due to a small size and array potential to provide discrete imaging speed improvements. Optical fibre exhibits numerous advantages over conventional piezo-electric transducers, such as immunity from electromagnetic interference...

  10. A Parallel Tracking Method for Acoustic Radiation Force Impulse Imaging

    Science.gov (United States)

    Dahl, Jeremy J.; Pinton, Gianmarco F.; Mark, L; Agrawal, Vineet; Nightingale, Kathryn R.; Trahey, Gregg E.

    2007-01-01

    Radiation force-based techniques have been developed by several groups for imaging the mechanical properties of tissue. Acoustic Radiation Force Impulse (ARFI) imaging is one such method that uses commercially available scanners to generate localized radiation forces in tissue. The response of the tissue to the radiation force is determined using conventional B-mode imaging pulses to track micron-scale displacements in tissue. Current research in ARFI imaging is focused on producing real-time images of tissue displacements and related mechanical properties. Obstacles to producing a real-time ARFI imaging modality include data acquisition, processing power, data transfer rates, heating of the transducer, and patient safety concerns. We propose a parallel receive beamforming technique to reduce transducer heating and patient acoustic exposure, and to facilitate data acquisition for real-time ARFI imaging. Custom beam sequencing was used with a Siemens SONOLINE AntaresTM scanner to track tissue displacements with parallel-receive beam-forming in tissue-mimicking phantoms. Using simulations, the effects of material properties on parallel tracking are observed. Transducer and tissue heating for parallel tracking are compared to standard ARFI beam sequencing. The effects of tracking beam position and size of the tracked region are also discussed in relation to the size and temporal response of the region of applied force, and the impact on ARFI image contrast and signal-to-noise ratio are quantified. PMID:17328327

  11. Acoustic and photoacoustic microscopy imaging of single leukocytes

    Science.gov (United States)

    Strohm, Eric M.; Moore, Michael J.; Kolios, Michael C.

    2016-03-01

    An acoustic/photoacoustic microscope was used to create micrometer resolution images of stained cells from a blood smear. Pulse echo ultrasound images were made using a 1000 MHz transducer with 1 μm resolution. Photoacoustic images were made using a fiber coupled 532 nm laser, where energy losses through stimulated Raman scattering enabled output wavelengths from 532 nm to 620 nm. The laser was focused onto the sample using a 20x objective, and the laser spot co-aligned with the 1000 MHz transducer opposite the laser. The blood smear was stained with Wright-Giemsa, a common metachromatic dye that differentially stains the cellular components for visual identification. A neutrophil, lymphocyte and a monocyte were imaged using acoustic and photoacoustic microscopy at two different wavelengths, 532 nm and 600 nm. Unique features in each imaging modality enabled identification of the different cell types. This imaging method provides a new way of imaging stained leukocytes, with applications towards identifying and differentiating cell types, and detecting disease at the single cell level.

  12. A combined parabolic-integral equation approach to the acoustic simulation of vibro-acoustic imaging.

    Science.gov (United States)

    Malcolm, A E; Reitich, F; Yang, J; Greenleaf, J F; Fatemi, M

    2008-11-01

    This paper aims to model ultrasound vibro-acoustography to improve our understanding of the underlying physics of the technique thus facilitating the collection of better images. Ultrasound vibro-acoustography is a novel imaging technique combining the resolution of high-frequency imaging with the clean (speckle-free) images obtained with lower frequency techniques. The challenge in modeling such an experiment is in the variety of scales important to the final image. In contrast to other approaches for modeling such problems, we break the experiment into three parts: high-frequency propagation, non-linear interaction and the propagation of the low-frequency acoustic emission. We then apply different modeling strategies to each part. For the high-frequency propagation we choose a parabolic approximation as the field has a strong preferred direction and small propagation angles. The non-linear interaction is calculated directly with Fourier methods for computing derivatives. Because of the low-frequency omnidirectional nature of the acoustic emission field and the piecewise constant medium we model the low-frequency field with a surface integral approach. We use our model to compare with experimental data and to visualize the relevant fields at points in the experiment where laboratory data is difficult to collect, in particular the source of the low-frequency field. To simulate experimental conditions we perform the simulations with the two frequencies 3 and 3.05 MHz with an inclusion of varying velocity submerged in water.

  13. Photo acoustic imaging: technology, systems and market trends

    Science.gov (United States)

    Faucheux, Marc; d'Humières, Benoît; Cochard, Jacques

    2017-03-01

    Although the Photo Acoustic effect was observed by Graham Bell in 1880, the first applications (gas analysis) occurred in 1970's using the required energetic light pulses from lasers. During mid 1990's medical imaging research begun to use Photo Acoustic effect and in vivo images were obtained in mid-2000. Since 2009, the number of patent related to Photo Acoustic Imaging (PAI) has dramatically increased. PAI machines for pre-clinical and small animal imaging have been being used in a routine way for several years. Based on its very interesting features (non-ionizing radiation, noninvasive, high depth resolution ratio, scalability, moderate price) and because it is able to deliver not only anatomical, but functional and molecular information, PAI is a very promising clinical imaging modality. It penetrates deeper into tissue than OCT (Optical Coherence Tomography) and provides a higher resolution than ultrasounds. The PAI is one of the most growing imaging modality and some innovative clinical systems are planned to be on market in 2017. Our study analyzes the different approaches such as photoacoustic computed tomography, 3D photoacoustic microscopy, multispectral photoacoustic tomography and endoscopy with the recent and tremendous technological progress over the past decade: advances in image reconstruction algorithms, laser technology, ultrasound detectors and miniaturization. We analyze which medical domains and applications are the most concerned and explain what should be the forthcoming medical system in the near future. We segment the market in four parts: Components and R&D, pre-clinical, analytics, clinical. We analyzed what should be, quantitatively and qualitatively, the PAI medical markets in each segment and its main trends. We point out the market accessibility (patents, regulations, clinical evaluations, clinical acceptance, funding). In conclusion, we explain the main market drivers and challenges to overcome and give a road map for medical

  14. Imaging of acoustic attenuation and speed of sound maps using photoacoustic measurements

    NARCIS (Netherlands)

    Willemink, Rene; Manohar, Srirang; Purwar, Y.; van der Heijden, Ferdinand; Slump, Cornelis H.; van Leeuwen, Ton; McAleavey, S.A.; D'Hooge, J.

    Photoacoustic imaging is an upcoming medical imaging modality with the potential of imaging both optical and acoustic properties of objects. We present a measurement system and outline reconstruction methods to image both speed of sound and acoustic attenuation distributions of an object using only

  15. a Three-Dimensional Acoustical Imaging System for Zooplankton Observations

    Science.gov (United States)

    McGehee, Duncan Ewell

    This dissertation describes the design, testing, and use of a three-dimensional acoustical imaging system, called Fish TV, or FTV, for tracking zooplankton swimming in situ. There is an increasing recognition that three -dimensional tracks of individual plankters are needed for some studies in behavioral ecology including, for example, the role of individual behavior in patch formation and maintenance. Fish TV was developed in part to provide a means of examining zooplankton swimming behavior in a non-invasive way. The system works by forming a set of 64 acoustic beams in an 8 by 8 pattern, each beam 2 ^circ by 2^circ , for a total coverage of 16^circ by 16^circ. The 8 by 8 beams form two dimensions of the image; range provides the third dimension. The system described in the thesis produces three-dimensional images at the rate of approximately one per second. A set of laboratory and field experiments is described that demonstrates the capabilities of the system. The final field experiment was the in situ observation of zooplankton swimming behavior at a site in the San Diego Trough, 15 nautical miles southwest of San Diego. 314 plankters were tracked for one minute. It was observed that there was no connection between the acoustic size of the animals and their repertoire of swimming behaviors. Other contributions of the dissertation include the development of two novel methods for generating acoustic beams with low side lobes. The first is the method of dense random arrays. The second is the optimum mean square quantized aperture method. Both methods were developed originally as ways to "build a better beam pattern" for Fish TV, but also have general significance with respect to aperture theory.

  16. Mutual conversion between B-mode image and acoustic impedance image

    Science.gov (United States)

    Chean, Tan Wei; Hozumi, Naohiro; Yoshida, Sachiko; Kobayashi, Kazuto; Ogura, Yuki

    2017-07-01

    To study the acoustic properties of a B-mode image, two ways of analysis methods were proposed in this report. The first method is the conversion of an acoustic impedance image into a B-mode image (Z to B). The time domain reflectometry theory and transmission line model were used as reference in the calculation. The second method is the direct a conversion of B-mode image into an acoustic impedance image (B to Z). The theoretical background of the second method is similar to that of the first method; however, the calculation is in the opposite direction. Significant scatter, refraction, and attenuation were assumed not to take place during the propagation of an ultrasonic wave. Hence, they were ignored in both calculations. In this study, rat cerebellar tissue and human cheek skin were used to determine the feasibility of the first and second methods respectively. Some good results are obtained and hence both methods showed their possible applications in the study of acoustic properties of B-mode images.

  17. Full-field imaging of nonclassical acoustic nonlinearity

    Science.gov (United States)

    Sarens, Bart; Kalogiannakis, Georgios; Glorieux, Christ; Van Hemelrijck, Danny

    2007-12-01

    The feasibility of full field shearographic detection of nonclassical acoustic nonlinearity is investigated. Traditional frequency analysis of the sinusoidally excited sample, as used in scanning techniques, turns out to be not practical due to the inherent optical detection nonlinearity of the shearography system itself. An alternative method, based on determining the asymmetry between shearographic images stroboscopically obtained for positive and negative displacements, is proposed. This approach allows us to easily and rapidly detect the tension-compression asymmetry which typically arises where nonbounded contact interface defects are present.

  18. Acoustic Radiation Force Impulse (ARFI) Imaging-Based Needle Visualization

    Science.gov (United States)

    Rotemberg, Veronica; Palmeri, Mark; Rosenzweig, Stephen; Grant, Stuart; Macleod, David; Nightingale, Kathryn

    2011-01-01

    Ultrasound-guided needle placement is widely used in the clinical setting, particularly for central venous catheter placement, tissue biopsy and regional anesthesia. Difficulties with ultrasound guidance in these areas often result from steep needle insertion angles and spatial offsets between the imaging plane and the needle. Acoustic Radiation Force Impulse (ARFI) imaging leads to improved needle visualization because it uses a standard diagnostic scanner to perform radiation force based elasticity imaging, creating a displacement map that displays tissue stiffness variations. The needle visualization in ARFI images is independent of needle-insertion angle and also extends needle visibility out of plane. Although ARFI images portray needles well, they often do not contain the usual B-mode landmarks. Therefore, a three-step segmentation algorithm has been developed to identify a needle in an ARFI image and overlay the needle prediction on a coregistered B-mode image. The steps are: (1) contrast enhancement by median filtration and Laplacian operator filtration, (2) noise suppression through displacement estimate correlation coefficient thresholding and (3) smoothing by removal of outliers and best-fit line prediction. The algorithm was applied to data sets from horizontal 18, 21 and 25 gauge needles between 0–4 mm offset in elevation from the transducer imaging plane and to 18G needles on the transducer axis (in plane) between 10° and 35° from the horizontal. Needle tips were visualized within 2 mm of their actual position for both horizontal needle orientations up to 1.5 mm off set in elevation from the transducer imaging plane and on-axis angled needles between 10°–35° above the horizontal orientation. We conclude that segmented ARFI images overlaid on matched B-mode images hold promise for improved needle visibility in many clinical applications. PMID:21608445

  19. Multi-crack imaging using nonclassical nonlinear acoustic method

    Science.gov (United States)

    Zhang, Lue; Zhang, Ying; Liu, Xiao-Zhou; Gong, Xiu-Fen

    2014-10-01

    Solid materials with cracks exhibit the nonclassical nonlinear acoustical behavior. The micro-defects in solid materials can be detected by nonlinear elastic wave spectroscopy (NEWS) method with a time-reversal (TR) mirror. While defects lie in viscoelastic solid material with different distances from one another, the nonlinear and hysteretic stress—strain relation is established with Preisach—Mayergoyz (PM) model in crack zone. Pulse inversion (PI) and TR methods are used in numerical simulation and defect locations can be determined from images obtained by the maximum value. Since false-positive defects might appear and degrade the imaging when the defects are located quite closely, the maximum value imaging with a time window is introduced to analyze how defects affect each other and how the fake one occurs. Furthermore, NEWS-TR-NEWS method is put forward to improve NEWS-TR scheme, with another forward propagation (NEWS) added to the existing phases (NEWS and TR). In the added phase, scanner locations are determined by locations of all defects imaged in previous phases, so that whether an imaged defect is real can be deduced. NEWS-TR-NEWS method is proved to be effective to distinguish real defects from the false-positive ones. Moreover, it is also helpful to detect the crack that is weaker than others during imaging procedure.

  20. Description and validation of a combination of acoustical radiosity and the image source method

    DEFF Research Database (Denmark)

    Marbjerg, Gerd Høy; Jeong, Cheol-Ho; Brunskog, Jonas

    2014-01-01

    to model both specular and diffuse reflections with complex-valued acoustical descriptions of the surfaces. This paper mainly describes the combination of the two models and the implementation of the angle dependent surface descriptions both in the image source model and in acoustical radiosity......A model that combines image source modelling and acoustical radiosity with complex boundary con- ditions, thus including phase shifts on reflection, has been developed. The model is denoted Phased Acoustical Radiosity and Image Source Model (PARISM). It has been developed in order to be able...

  1. Ultrasonic phased array with surface acoustic wave for imaging cracks

    Directory of Open Access Journals (Sweden)

    Yoshikazu Ohara

    2017-06-01

    Full Text Available To accurately measure crack lengths, we developed a real-time surface imaging method (SAW PA combining an ultrasonic phased array (PA with a surface acoustic wave (SAW. SAW PA using a Rayleigh wave with a high sensitivity to surface defects was implemented for contact testing using a wedge with the third critical angle that allows the Rayleigh wave to be generated. Here, to realize high sensitivity imaging, SAW PA was optimized in terms of the wedge and the imaging area. The improved SAW PA was experimentally demonstrated using a fatigue crack specimen made of an aluminum alloy. For further verification in more realistic specimens, SAW PA was applied to stainless-steel specimens with a fatigue crack and stress corrosion cracks (SCCs. The fatigue crack was visualized with a high signal-to-noise ratio (SNR and its length was measured with a high accuracy of better than 1 mm. The SCCs generated in the heat-affected zones (HAZs of a weld were successfully visualized with a satisfactory SNR, although responses at coarse grains appeared throughout the imaging area. The SCC lengths were accurately measured. The imaging results also precisely showed complicated distributions of SCCs, which were in excellent agreement with the optically observed distributions.

  2. Quantifying Image Quality Improvement Using Elevated Acoustic Output in B-Mode Harmonic Imaging.

    Science.gov (United States)

    Deng, Yufeng; Palmeri, Mark L; Rouze, Ned C; Trahey, Gregg E; Haystead, Clare M; Nightingale, Kathryn R

    2017-10-01

    Tissue harmonic imaging has been widely used in abdominal imaging because of its significant reduction in acoustic noise compared with fundamental imaging. However, tissue harmonic imaging can be limited by both signal-to-noise ratio and penetration depth during clinical imaging, resulting in decreased diagnostic utility. A logical approach would be to increase the source pressure, but the in situ pressures used in diagnostic ultrasound are subject to a de facto upper limit based on the U.S. Food and Drug Administration guideline for the mechanical index (harmonic imaging using a transmit frequency of 1.8 MHz. The results indicate that harmonic imaging using elevated acoustic output leads to modest improvements (3%-7%) in contrast-to-noise ratio of hypo-echoic hepatic vessels and increases in imaging penetration depth on the order of 4 mm per mechanical index increase of 0.1 for a given focal depth. Difficult-to-image patients who suffer from poor ultrasound image quality exhibited larger improvements than easy-to-image study participants. Copyright © 2017 World Federation for Ultrasound in Medicine & Biology. Published by Elsevier Inc. All rights reserved.

  3. Comparison of sonochemiluminescence images using image analysis techniques and identification of acoustic pressure fields via simulation.

    Science.gov (United States)

    Tiong, T Joyce; Chandesa, Tissa; Yap, Yeow Hong

    2017-05-01

    One common method to determine the existence of cavitational activity in power ultrasonics systems is by capturing images of sonoluminescence (SL) or sonochemiluminescence (SCL) in a dark environment. Conventionally, the light emitted from SL or SCL was detected based on the number of photons. Though this method is effective, it could not identify the sonochemical zones of an ultrasonic systems. SL/SCL images, on the other hand, enable identification of 'active' sonochemical zones. However, these images often provide just qualitative data as the harvesting of light intensity data from the images is tedious and require high resolution images. In this work, we propose a new image analysis technique using pseudo-colouring images to quantify the SCL zones based on the intensities of the SCL images and followed by comparison of the active SCL zones with COMSOL simulated acoustic pressure zones. Copyright © 2016 Elsevier B.V. All rights reserved.

  4. From acoustic segmentation to language processing: evidence from optical imaging

    Directory of Open Access Journals (Sweden)

    Hellmuth Obrig

    2010-06-01

    Full Text Available During language acquisition in infancy and when learning a foreign language, the segmentation of the auditory stream into words and phrases is a complex process. Intuitively, learners use ‘anchors’ to segment the acoustic speech stream into meaningful units like words and phrases. Regularities on a segmental (e.g., phonological or suprasegmental (e.g., prosodic level can provide such anchors. Regarding the neuronal processing of these two kinds of linguistic cues a left hemispheric dominance for segmental and a right hemispheric bias for suprasegmental information has been reported in adults. Though lateralization is common in a number of higher cognitive functions, its prominence in language may also be a key to understanding the rapid emergence of the language network in infants and the ease at which we master our language in adulthood. One question here is whether the hemispheric lateralization is driven by linguistic input per se or whether non-linguistic, especially acoustic factors, ‘guide’ the lateralization process. Methodologically, fMRI provides unsurpassed anatomical detail for such an enquiry. However, instrumental noise, experimental constraints and interference with EEG assessment limit its applicability, pointedly in infants and also when investigating the link between auditory and linguistic processing. Optical methods have the potential to fill this gap. Here we review a number of recent studies using optical imaging to investigate hemispheric differences during segmentation and basic auditory feature analysis in language development.

  5. Using a Planar Array of MEMS Microphones to Obtain Acoustic Images of a Fan Matrix

    Directory of Open Access Journals (Sweden)

    Lara del Val

    2017-01-01

    Full Text Available This paper proposes the use of a signal acquisition and processing system based on an 8×8 planar array of MEMS (Microelectromechanical Systems microphones to obtain acoustic images of a fan matrix. A 3×3 matrix of PC fans has been implemented to perform the study. Some tests to obtain the acoustic images of the individual fans and of the whole matrix have been defined and have been carried out inside an anechoic chamber. The nonstationary signals received by each MEMS microphone and their corresponding spectra have been analyzed, as well as the corresponding acoustic images. The analysis of the acoustic signals spectra reveals the resonance frequency of the individual fans. The obtained results reveal the feasibility of the proposed system to obtained acoustic images of a fan matrix and of its individual fans, in this last case, in order to estimate the real position of the fan inside the matrix.

  6. Standing tree decay detection by using acoustic tomography images

    Science.gov (United States)

    Espinosa, Luis F.; Arciniegas, Andres F.; Prieto, Flavio A.; Cortes, Yolima; Brancheriau, Loïc.

    2015-04-01

    The acoustic tomographic technique is used in the diagnosis process of standing trees. This paper presents a segmentation methodology to separate defective regions in cross-section tomographic images obtained with Arbotom® device. A set of experiments was proposed using two trunk samples obtained from a eucalyptus tree, simulating defects by drilling holes with known geometry, size and position and using different number of sensors. Also, tomographic images from trees presenting real defects were studied, by testing two different species with significant internal decay. Tomographic images and photographs from the trunk cross-section were processed to align the propagation velocity data with a corresponding region, healthy or defective. The segmentation was performed by finding a velocity threshold value to separate the defective region; a logistic regression model was fitted to obtain the value that maximizes a performance criterion, being selected the geometric mean. Accuracy segmentation values increased as the number of sensors augmented; also the position influenced the result, obtaining improved results in the case of centric defects.

  7. Frequency-Modulated Magneto-Acoustic Detection and Imaging: Challenges, Experimental Procedures, and B-Scan Images

    CERN Document Server

    Aliroteh, Miaad S; Arbabian, Amin

    2016-01-01

    Magneto-acoustic tomography combines near-field radio-frequency (RF) and ultrasound with the aim of creating a safe, high resolution, high contrast hybrid imaging technique. We present continuous-wave magneto-acoustic imaging techniques, which improve SNR and/or reduce the required peak-to-average excitation power ratio, to make further integration and larger fields of view feasible. This method relies on the coherency between RF excitation and the resulting ultrasound generated through Lorentz force interactions, which was confirmed by our previous work. We provide detailed methodology, clarify the details of experiments, and explain how the presence of magneto-acoustic phenomenon was verified. An example magneto-acoustic B-scan image is acquired in order to illustrate the capability of magneto-acoustic tomography in highlighting boundaries where electrical conductivity alters, such as between different tissues.

  8. Dual Frequency Acoustic Droplet Vaporization Detection for Medical Imaging

    Science.gov (United States)

    Arena, Christopher B.; Novell, Anthony; Sheeran, Paul S.; Puett, Connor; Moyer, Linsey C.; Dayton, Paul A.

    2017-01-01

    Liquid-filled perfluorocarbon droplets emit a unique acoustic signature when vaporized into to gas-filled microbubbles using ultrasound. Here, we conducted a pilot study in a tissue-mimicking flow phantom to explore the spatial aspects of droplet vaporization and investigate the effects of applied pressure and droplet concentration on image contrast and axial and lateral resolution. Control microbubble contrast agents were used for comparison. A confocal dual-frequency transducer was used to transmit at 8 MHz and passively receive at 1 MHz. Droplet signals were of significantly higher energy than microbubble signals. This resulted in improved signal separation and high contrast-to-tissue ratios (CTR). Specifically, with a peak negative pressure (PNP) of 450 kPa applied at the focus, the CTR of B-mode images was 18.3 dB for droplets and −0.4 for microbubbles. The lateral resolution was dictated by the size of the droplet activation area, with lower pressures resulting in smaller activation areas and improved lateral resolution (0.67 mm at 450 kPa). The axial resolution in droplet images was dictated by the size of the initial droplet and independent of the properties of the transmit pulse (3.86 mm at 450 kPa). In post-processing, time-domain averaging (TDA) improved droplet and microbubble signal separation at high pressures (640 kPa and 700 kPa). Taken together, these results indicate that it is possible to generate high-sensitivity, high-contrast images of vaporization events. In the future, this has the potential to be applied in combination with droplet-mediated therapy to track treatment outcomes or as a stand-alone diagnostic system to monitor the physical properties of the surrounding environment. PMID:26415125

  9. Auralizations with loudspeaker arrays from a phased combination of the image source method and acoustical radiosity

    DEFF Research Database (Denmark)

    Marbjerg, Gerd Høy; Brunskog, Jonas; Jeong, Cheol-Ho

    2017-01-01

    In order to create a simulation tool that is well-suited for small rooms with low diffusion and highly absorbing ceilings, a new room acoustic simulation tool has been developed that combines a phased version of the image source with acoustical radiosity and that considers the angle dependence of...

  10. Detection of Breast Microcalcifications Under Ultrasound Using Power Doppler and Acoustic Resonance Imaging

    National Research Council Canada - National Science Library

    Weinstein, Susan

    2003-01-01

    .... Our goal with our current project was to utilize breast sonography coupled with the technique of acoustic resonance to image and evaluate the breast micorcalcifications in patients prior to biopsy...

  11. Demonstration of acoustic source localization in air using single pixel compressive imaging

    Science.gov (United States)

    Rogers, Jeffrey S.; Rohde, Charles A.; Guild, Matthew D.; Naify, Christina J.; Martin, Theodore P.; Orris, Gregory J.

    2017-12-01

    Acoustic source localization often relies on large sensor arrays that can be electronically complex and have large data storage requirements to process element level data. Recently, the concept of a single-pixel-imager has garnered interest in the electromagnetics literature due to its ability to form high quality images with a single receiver paired with shaped aperture screens that allow for the collection of spatially orthogonal measurements. Here, we present a method for creating an acoustic analog to the single-pixel-imager found in electromagnetics for the purpose of source localization. Additionally, diffraction is considered to account for screen openings comparable to the acoustic wavelength. A diffraction model is presented and incorporated into the single pixel framework. In this paper, we explore the possibility of applying single pixel localization to acoustic measurements. The method is experimentally validated with laboratory measurements made in an air waveguide.

  12. Evaluating Image Precision of Acoustical Imaging Diffraction by Focused Ultrasound Beam

    National Research Council Canada - National Science Library

    Jinwen Ding; Dewen Zheng; Han Ding; Kang Li; Qichen Ma; Guochao He; Jingjing Liu; Junhua Chen

    2017-01-01

      The paper concisely reveals an acoustic behavior - acoustic diffraction (scattering) phenomena, which arises between a spherical cavity of acoustic lens and the microstructure of an object in immersion...

  13. Functional analysis of voice using simultaneous high-speed imaging and acoustic recordings.

    Science.gov (United States)

    Yan, Yuling; Damrose, Edward; Bless, Diane

    2007-09-01

    We present a comprehensive, functional analysis of clinical voice data derived from both high-speed digital imaging (HSDI) of the larynx and simultaneously acquired acoustic recordings. The goals of this study are to: (1) correlate dynamic characteristics of the vocal folds derived from direct laryngeal imaging with indirectly acquired acoustic measurements; (2) define the advantages of using a combined imaging/acoustic approach for the analysis of voice condition; and (3) identify new quantitative measures to evaluate the regularity of the vocal fold vibration and the complexity of the vocal output -- these measures will be key to successful diagnosis of vocal abnormalities. Image- and acoustic-based analyses are performed using an analytic phase plot approach previously introduced by our group (referred to as 'Nyquist' plot). Fast Fourier Transform (FFT) spectral analyses are performed on the same data for a comparison. Clinical HSDI and acoustic recordings from subjects having normal and specific voice pathologies, including muscular tension dysphonia (MTD) and recurrent respiratory papillomatosis (RRP) were analyzed using the Nyquist plot approach. The results of these analyses show that a combined imaging/acoustic analysis approach provides better characterization of the vibratory behavior of the vocal folds as it correlates with vocal output and pathology.

  14. Auralisations with loudspeaker arrays from a phased combination of the image source method and acoustical radiosity

    DEFF Research Database (Denmark)

    Marbjerg, Gerd Høy

    2017-01-01

    In order to create a simulation tool that is well-suited for small rooms with low diffusion and highly absorbing ceilings, a new room acoustic simulation tool has been developed that combines a phased version of the image source with acoustical radiosity and that considers the angle dependence...... with PARISM are described and compared to implementations of auralisations with another geometrical acoustic simulation tool, i.e. ODEON and the LoRA toolbox that applies Ambisonics to ODEON simulations. In opposition to the LoRA toolbox, higher order Ambisonics are also applied to the late part of the PARISM...

  15. Reconstructed imaging of acoustic cloak using time-lapse reversal method

    Science.gov (United States)

    Zhou, Chen; Cheng, Ying; Xu, Jian-yi; Li, Bo; Liu, Xiao-jun

    2014-08-01

    We proposed and investigated a solution to the inverse acoustic cloak problem, an anti-stealth technology to make cloaks visible, using the time-lapse reversal (TLR) method. The TLR method reconstructs the image of an unknown acoustic cloak by utilizing scattered acoustic waves. Compared to previous anti-stealth methods, the TLR method can determine not only the existence of a cloak but also its exact geometric information like definite shape, size, and position. Here, we present the process for TLR reconstruction based on time reversal invariance. This technology may have potential applications in detecting various types of cloaks with different geometric parameters.

  16. A combination of the acoustic radiosity and the image source method

    DEFF Research Database (Denmark)

    Koutsouris, Georgios I.; Brunskog, Jonas; Jeong, Cheol-Ho

    2012-01-01

    A combined model for room acoustic predictions is developed, aiming to treat both diffuse and specular reflections in a unified way. Two established methods are incorporated: acoustical radiosity, accounting for the diffuse part, and the image source method, accounting for the specular part....... The model is based on conservation of acoustical energy. Losses are taken into account by the energy absorption coefficient, and the diffuse reflections are controlled via the scattering coefficient, which defines the portion of energy that has been diffusely reflected. The way the model is formulated...

  17. Comparing a phased combination of acoustical radiosity and the image source method with other simulation tools

    DEFF Research Database (Denmark)

    Marbjerg, Gerd Høy; Brunskog, Jonas; Jeong, Cheol-Ho

    2015-01-01

    A phased combination of acoustical radiosity and the image source method (PARISM) has been developed in order to be able to model both specular and diffuse reflections with angle-dependent and complex-valued acoustical descriptions of the surfaces. It is of great interest to model both specular...... and diffuse reflections when simulating the acoustics of small rooms with non-diffuse sound fields, since scattering from walls add to the diffuseness in the room. This room type is often seen in class rooms and offices, as they are often small rectangular rooms with most of the absorption placed...

  18. Sensitivity improvement of optical fiber acoustic probe for all-optical photoacoustic imaging system

    Science.gov (United States)

    Seki, Atsushi; Iwai, Katsumasa; Katagiri, Takashi; Matsuura, Yuji

    2017-07-01

    An acoustic probe based on a Fabry-Perot interferometer composed of a polymer film attached to the end of an optical fiber was designed and fabricated for an endoscopic, all-optical photoacoustic imaging system. The finesse of the interferometer was improved by forming a half-mirror at the end of the fiber and a partial reflection mirror on the outer surface of the polymer film. A photoacoustic imaging system was constructed by combining the fiber-optic acoustic probe with a bundle of hollow optical fibers used for the excitation of the photoacoustic wave, and an image of blood capillaries in a fish ovarian membrane was successfully obtained.

  19. Acoustic noise reduction in T 1- and proton-density-weighted turbo spin-echo imaging.

    Science.gov (United States)

    Ott, Martin; Blaimer, Martin; Breuer, Felix; Grodzki, David; Heismann, Björn; Jakob, Peter

    2016-02-01

    To reduce acoustic noise levels in T 1-weighted and proton-density-weighted turbo spin-echo (TSE) sequences, which typically reach acoustic noise levels up to 100 dB(A) in clinical practice. Five acoustic noise reduction strategies were combined: (1) gradient ramps and shapes were changed from trapezoidal to triangular, (2) variable-encoding-time imaging was implemented to relax the phase-encoding gradient timing, (3) RF pulses were adapted to avoid the need for reversing the polarity of the slice-rewinding gradient, (4) readout bandwidth was increased to provide more time for gradient activity on other axes, (5) the number of slices per TR was reduced to limit the total gradient activity per unit time. We evaluated the influence of each measure on the acoustic noise level, and conducted in vivo measurements on a healthy volunteer. Sound recordings were taken for comparison. An overall acoustic noise reduction of up to 16.8 dB(A) was obtained by the proposed strategies (1-4) and the acquisition of half the number of slices per TR only. Image quality in terms of SNR and CNR was found to be preserved. The proposed measures in this study allowed a threefold reduction in the acoustic perception of T 1-weighted and proton-density-weighted TSE sequences compared to a standard TSE-acquisition. This could be achieved without visible degradation of image quality, showing the potential to improve patient comfort and scan acceptability.

  20. Segmentation of the spinous process and its acoustic shadow in vertebral ultrasound images.

    Science.gov (United States)

    Berton, Florian; Cheriet, Farida; Miron, Marie-Claude; Laporte, Catherine

    2016-05-01

    Spinal ultrasound imaging is emerging as a low-cost, radiation-free alternative to conventional X-ray imaging for the clinical follow-up of patients with scoliosis. Currently, deformity measurement relies almost entirely on manual identification of key vertebral landmarks. However, the interpretation of vertebral ultrasound images is challenging, primarily because acoustic waves are entirely reflected by bone. To alleviate this problem, we propose an algorithm to segment these images into three regions: the spinous process, its acoustic shadow and other tissues. This method consists, first, in the extraction of several image features and the selection of the most relevant ones for the discrimination of the three regions. Then, using this set of features and linear discriminant analysis, each pixel of the image is classified as belonging to one of the three regions. Finally, the image is segmented by regularizing the pixel-wise classification results to account for some geometrical properties of vertebrae. The feature set was first validated by analyzing the classification results across a learning database. The database contained 107 vertebral ultrasound images acquired with convex and linear probes. Classification rates of 84%, 92% and 91% were achieved for the spinous process, the acoustic shadow and other tissues, respectively. Dice similarity coefficients of 0.72 and 0.88 were obtained respectively for the spinous process and acoustic shadow, confirming that the proposed method accurately segments the spinous process and its acoustic shadow in vertebral ultrasound images. Furthermore, the centroid of the automatically segmented spinous process was located at an average distance of 0.38 mm from that of the manually labeled spinous process, which is on the order of image resolution. This suggests that the proposed method is a promising tool for the measurement of the Spinous Process Angle and, more generally, for assisting ultrasound-based assessment of scoliosis

  1. Segmentation and classification of shallow subbottom acoustic data, using image processing and neural networks

    Science.gov (United States)

    Yegireddi, Satyanarayana; Thomas, Nitheesh

    2014-06-01

    Subbottom acoustic profiler provides acoustic imaging of the subbottom structure constituting the upper sediment layers of the seabed, which is essential for geological and offshore geo-engineering studies. Delineation of the subbottom structure from a noisy acoustic data and classification of the sediment strata is a challenging task with the conventional signal processing techniques. Image processing techniques utilise the spatial variability of the image characteristics, known for their potential in medical imaging and pattern recognition applications. In the present study, they are found to be good in demarcating the boundaries of the sediment layers associated with weak acoustic reflectivity, masked by noisy background. The study deals with application of image processing techniques, like segmentation in identification of subbottom features and extraction of textural feature vectors using grey level co-occurrence matrix statistics. And also attempted classification using Self Organised Map, an unsupervised neural network model utilising these feature vectors. The methodology was successfully demonstrated in demarcating the different sediment layers from the subbottom images and established the sediments constituting the inferred four subsurface sediment layers differ from each other. The network model was also tested for its consistency, with repeated runs of different configuration of the network. Also the ability of simulated network was tested using a few untrained test images representing the similar environment and the classification results show a good agreement with the anticipated.

  2. Time-domain imaging of gigahertz surface waves on an acoustic metamaterial

    Science.gov (United States)

    Otsuka, Paul H.; Mezil, Sylvain; Matsuda, Osamu; Tomoda, Motonobu; Maznev, Alexei A.; Gan, Tian; Fang, Nicholas; Boechler, Nicholas; Gusev, Vitalyi E.; Wright, Oliver B.

    2018-01-01

    We extend time-domain imaging in acoustic metamaterials to gigahertz frequencies. Using a sample consisting of a regular array of ∼1 μm diameter silica microspheres forming a two-dimensional triangular lattice on a substrate, we implement an ultrafast technique to probe surface acoustic wave propagation inside the metamaterial area and incident on the metamaterial from a region containing no microspheres, which reveals the acoustic metamaterial dispersion, the presence of band gaps and the acoustic transmission properties of the interface. A theoretical model of this locally resonant metamaterial based on normal and shear-rotational resonances of the spheres fits the data well. Using this model, we show analytically how the sphere elastic coupling parameters influence the gap widths.

  3. Acoustical cross-talk in row–column addressed 2-D transducer arrays for ultrasound imaging

    DEFF Research Database (Denmark)

    Christiansen, Thomas Lehrmann; Jensen, Jørgen Arendt; Thomsen, Erik Vilain

    2015-01-01

    The acoustical cross-talk in row–column addressed 2-D transducer arrays for volumetric ultrasound imaging is investigated. Experimental results from a 2.7 MHz, λ/2-pitch capacitive micromachined ultrasonic transducer (CMUT) array with 62 rows and 62 columns are presented and analyzed in the frequ......The acoustical cross-talk in row–column addressed 2-D transducer arrays for volumetric ultrasound imaging is investigated. Experimental results from a 2.7 MHz, λ/2-pitch capacitive micromachined ultrasonic transducer (CMUT) array with 62 rows and 62 columns are presented and analyzed...

  4. Development and validation of a combined phased acoustical radiosity and image source model for predicting sound fields in rooms

    DEFF Research Database (Denmark)

    Marbjerg, Gerd Høy; Brunskog, Jonas; Jeong, Cheol-Ho

    2015-01-01

    A model, combining acoustical radiosity and the image source method, including phase shifts on reflection, has been developed. The model is denoted Phased Acoustical Radiosity and Image Source Method (PARISM), and it has been developed in order to be able to model both specular and diffuse reflec...

  5. Imaging acoustic vibrations in an ear model using spectrally encoded interferometry

    Science.gov (United States)

    Grechin, Sveta; Yelin, Dvir

    2018-01-01

    Imaging vibrational patterns of the tympanic membrane would allow an accurate measurement of its mechanical properties and provide early diagnosis of various hearing disorders. Various optical technologies have been suggested to address this challenge and demonstrated in vitro using point scanning and full-field interferometry. Spectrally encoded imaging has been previously demonstrated capable of imaging tissue acoustic vibrations with high spatial resolution, including two-dimensional phase and amplitude mapping. In this work, we demonstrate a compact optical apparatus for imaging acoustic vibrations that could be incorporated into a commercially available digital otoscope. By transmitting harmonic sound waves through the otoscope insufflation port and analyzing the spectral interferograms using custom-built software, we demonstrate high-resolution vibration imaging of a circular rubber membrane within an ear model.

  6. A combined microphone and camera calibration technique with application to acoustic imaging.

    Science.gov (United States)

    Legg, Mathew; Bradley, Stuart

    2013-10-01

    We present a calibration technique for an acoustic imaging microphone array, combined with a digital camera. Computer vision and acoustic time of arrival data are used to obtain microphone coordinates in the camera reference frame. Our new method allows acoustic maps to be plotted onto the camera images without the need for additional camera alignment or calibration. Microphones and cameras may be placed in an ad-hoc arrangement and, after calibration, the coordinates of the microphones are known in the reference frame of a camera in the array. No prior knowledge of microphone positions, inter-microphone spacings, or air temperature is required. This technique is applied to a spherical microphone array and a mean difference of 3 mm was obtained between the coordinates obtained with this calibration technique and those measured using a precision mechanical method.

  7. Damage imaging in nonlinear vibro-acoustic modulation tests

    Science.gov (United States)

    Pieczonka, Lukasz; Klepka, Andrzej; Uhl, Tadeusz; Staszewski, Wieslaw J.

    2015-03-01

    The paper deals with the nonlinear vibro-acoustic modulation technique (VAM) used for nondestructive damage detection in composites. In its original form the technique allows only for the determination of the presence of damage in a structure. This paper presents an enhancement of the technique that allows also for the determination of damage location. Experimental testing of the proposed procedure is performed on carbon fiber/epoxy laminated composite plates with barely visible impact damage that was generated in an impact test. Shearography was used to verify damage location. Piezoceramic actuators are used for vibration excitation and a scanning laser vibrometer is used for data acquisition.

  8. Biologically relevant photoacoustic imaging phantoms with tunable optical and acoustic properties

    Science.gov (United States)

    Vogt, William C.; Jia, Congxian; Wear, Keith A.; Garra, Brian S.; Joshua Pfefer, T.

    2016-10-01

    Established medical imaging technologies such as magnetic resonance imaging and computed tomography rely on well-validated tissue-simulating phantoms for standardized testing of device image quality. The availability of high-quality phantoms for optical-acoustic diagnostics such as photoacoustic tomography (PAT) will facilitate standardization and clinical translation of these emerging approaches. Materials used in prior PAT phantoms do not provide a suitable combination of long-term stability and realistic acoustic and optical properties. Therefore, we have investigated the use of custom polyvinyl chloride plastisol (PVCP) formulations for imaging phantoms and identified a dual-plasticizer approach that provides biologically relevant ranges of relevant properties. Speed of sound and acoustic attenuation were determined over a frequency range of 4 to 9 MHz and optical absorption and scattering over a wavelength range of 400 to 1100 nm. We present characterization of several PVCP formulations, including one designed to mimic breast tissue. This material is used to construct a phantom comprised of an array of cylindrical, hemoglobin-filled inclusions for evaluation of penetration depth. Measurements with a custom near-infrared PAT imager provide quantitative and qualitative comparisons of phantom and tissue images. Results indicate that our PVCP material is uniquely suitable for PAT system image quality evaluation and may provide a practical tool for device validation and intercomparison.

  9. Biologically relevant photoacoustic imaging phantoms with tunable optical and acoustic properties.

    Science.gov (United States)

    Vogt, William C; Jia, Congxian; Wear, Keith A; Garra, Brian S; Joshua Pfefer, T

    2016-10-01

    Established medical imaging technologies such as magnetic resonance imaging and computed tomography rely on well-validated tissue-simulating phantoms for standardized testing of device image quality. The availability of high-quality phantoms for optical-acoustic diagnostics such as photoacoustic tomography (PAT) will facilitate standardization and clinical translation of these emerging approaches. Materials used in prior PAT phantoms do not provide a suitable combination of long-term stability and realistic acoustic and optical properties. Therefore, we have investigated the use of custom polyvinyl chloride plastisol (PVCP) formulations for imaging phantoms and identified a dual-plasticizer approach that provides biologically relevant ranges of relevant properties. Speed of sound and acoustic attenuation were determined over a frequency range of 4 to 9 MHz and optical absorption and scattering over a wavelength range of 400 to 1100 nm. We present characterization of several PVCP formulations, including one designed to mimic breast tissue. This material is used to construct a phantom comprised of an array of cylindrical, hemoglobin-filled inclusions for evaluation of penetration depth. Measurements with a custom near-infrared PAT imager provide quantitative and qualitative comparisons of phantom and tissue images. Results indicate that our PVCP material is uniquely suitable for PAT system image quality evaluation and may provide a practical tool for device validation and intercomparison.

  10. A line array based near field imaging technique for characterising acoustical properties of elongated targets

    NARCIS (Netherlands)

    Driessen, F.P.G.

    1995-01-01

    With near field imaging techniques the acoustical pressure waves at distances other than the recorded can be calculated. Normally, acquisition on a two dimensional plane is necessary and extrapolation is performed by a Rayleigh integral. A near field single line instead of two dimensional plane

  11. Method and system to synchronize acoustic therapy with ultrasound imaging

    Science.gov (United States)

    Owen, Neil (Inventor); Bailey, Michael R. (Inventor); Hossack, James (Inventor)

    2009-01-01

    Interference in ultrasound imaging when used in connection with high intensity focused ultrasound (HIFU) is avoided by employing a synchronization signal to control the HIFU signal. Unless the timing of the HIFU transducer is controlled, its output will substantially overwhelm the signal produced by ultrasound imaging system and obscure the image it produces. The synchronization signal employed to control the HIFU transducer is obtained without requiring modification of the ultrasound imaging system. Signals corresponding to scattered ultrasound imaging waves are collected using either the HIFU transducer or a dedicated receiver. A synchronization processor manipulates the scattered ultrasound imaging signals to achieve the synchronization signal, which is then used to control the HIFU bursts so as to substantially reduce or eliminate HIFU interference in the ultrasound image. The synchronization processor can alternatively be implemented using a computing device or an application-specific circuit.

  12. Photo-Acoustic Ultrasound Imaging to Distinguish Benign from Malignant Prostate Cancer

    Science.gov (United States)

    2016-09-01

    High Frequency Pulsed Electric Fields and X-Ray Irradiation, IEEE Transactions on Biomedical Engineering, Under Review, acknowledgment of federal...University Page 2 of 13 1. INTRODUCTION: Ultrasound imaging uses sound waves at frequencies above the human hearing range to image organs within the body...An ultrasound transducer delivers a pulse of acoustic energy into the area of interest and listens for the echoes which return as the sound waves

  13. 77 FR 42802 - Section 4(f) Policy Paper

    Science.gov (United States)

    2012-07-20

    ...) Section 4(f) Statement and Determination for Independent Bikeway or Walkway Construction Projects (2... delayed due to Section 4(f) processing is minimized. Ideally, applicants should strive to make the...

  14. 77 FR 321 - Section 4(f) Policy Paper

    Science.gov (United States)

    2012-01-04

    ... Federal Highway Administration Section 4(f) Policy Paper AGENCY: Federal Highway Administration (FHWA... draft Section 4(f) Policy Paper that will provide guidance on the procedures the FHWA will follow when... practicable. Background A copy of the proposed Section 4(f) Policy Paper is available for download and public...

  15. Design and Evaluation of a Scalable and Reconfigurable Multi-Platform System for Acoustic Imaging

    Directory of Open Access Journals (Sweden)

    Alberto Izquierdo

    2016-10-01

    Full Text Available This paper proposes a scalable and multi-platform framework for signal acquisition and processing, which allows for the generation of acoustic images using planar arrays of MEMS (Micro-Electro-Mechanical Systems microphones with low development and deployment costs. Acoustic characterization of MEMS sensors was performed, and the beam pattern of a module, based on an 8 × 8 planar array and of several clusters of modules, was obtained. A flexible framework, formed by an FPGA, an embedded processor, a computer desktop, and a graphic processing unit, was defined. The processing times of the algorithms used to obtain the acoustic images, including signal processing and wideband beamforming via FFT, were evaluated in each subsystem of the framework. Based on this analysis, three frameworks are proposed, defined by the specific subsystems used and the algorithms shared. Finally, a set of acoustic images obtained from sound reflected from a person are presented as a case study in the field of biometric identification. These results reveal the feasibility of the proposed system.

  16. Modern Techniques in Acoustical Signal and Image Processing

    Energy Technology Data Exchange (ETDEWEB)

    Candy, J V

    2002-04-04

    Acoustical signal processing problems can lead to some complex and intricate techniques to extract the desired information from noisy, sometimes inadequate, measurements. The challenge is to formulate a meaningful strategy that is aimed at performing the processing required even in the face of uncertainties. This strategy can be as simple as a transformation of the measured data to another domain for analysis or as complex as embedding a full-scale propagation model into the processor. The aims of both approaches are the same--to extract the desired information and reject the extraneous, that is, develop a signal processing scheme to achieve this goal. In this paper, we briefly discuss this underlying philosophy from a ''bottom-up'' approach enabling the problem to dictate the solution rather than visa-versa.

  17. Acoustic rhinometry (AR): An Alternative Method to Image Nasal Airway Geometry

    DEFF Research Database (Denmark)

    Straszek, Sune; Pedersen, O.F.

    animals. Future prospects therefore could include development of new algorithms for computing data, more sensitive microphones measuring higher frequencies and optimal relationship between sound tube dimensions and the cavity measured. Achieving that may improve measurements, making pharmacological......  ACOUSTIC RHINOMETRY (AR): AN ALTERNATIVE METHOD TO IMAGE NASAL AIRWAY GEOMETRY.  INTRODUCTION AND BACKGROUND:  In human studies the acoustic reflection technique was first applied to describe the area-distance relationship of the lower airways, but later the acoustic reflection technique appeared...... Fourier transform. Based on the Ware and Aki algorithm measurements are displayed as an area-distance curve where cross-sectional area of the nasal cavity is a function of distance travelled by the sound wave.     DEMONSTRATION[OFP2] : Current problems using AR are demonstrated based on results from a few...

  18. Photo-acoustic imaging of coronary arteries with polymer optical fibers

    DEFF Research Database (Denmark)

    Woyessa, Getinet; Broadway, Christian; Lamela, Horacio

    2014-01-01

    Coronary artery disease (CAD) is one of the most common types of heart disease which happens when the arteries that supply blood to heart muscle become hardened and narrowed. This is caused by the building of cholesterol plaques on the inner walls of arteries. The gradual growth of plaques cause...... less blood to flow through the arteries hence the heart muscle can't get the blood or oxygen it needs. Worse, a plaque can suddenly rupture. As a result, blood clot over the rapture and suddenly cut off the hearts’ blood supply, causing permanent heart dama ge or stroke [1]. Photo-acoustic imaging...... relies on exposing lipids to a laser capable of inducing photo-acoustic effect and a sensor affected by the induced pressure. Polymer optical fibre Bragg grating and Fabry-Perot sensors will be developed for detection of photo-acoustic signal in collaboration of Optoelectronics and Laser technology group...

  19. Terahertz Spectroscopy and Brewster Angle Reflection Imaging of Acoustic Tiles

    Directory of Open Access Journals (Sweden)

    Patrick Kilcullen

    2017-01-01

    Full Text Available A Brewster angle reflection imaging apparatus is demonstrated which is capable of detecting hidden water-filled voids in a rubber tile sample. This imaging application simulates a real-world hull inspection problem for Royal Canadian Navy Victoria-class submarines. The tile samples represent a challenging imaging application due to their large refractive index and absorption coefficient. With a rubber transmission window at approximately 80 GHz, terahertz (THz sensing methods have shown promise for probing these structures in the laboratory. Operating at Brewster’s angle allows for the typically strong front surface reflection to be minimized while also conveniently making the method insensitive to air-filled voids. Using a broadband THz time-domain waveform imaging system (THz-TDS, we demonstrate satisfactory imaging and detection of water-filled voids without complicated signal processing. Optical properties of the tile samples at low THz frequencies are also reported.

  20. Analysis list: E4f1 [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available E4f1 Embryonic fibroblast + mm9 http://dbarchive.biosciencedbc.jp/kyushu-u/mm9/target/E4f1....1.tsv http://dbarchive.biosciencedbc.jp/kyushu-u/mm9/target/E4f1.5.tsv http://dbarchive.biosciencedb...c.jp/kyushu-u/mm9/target/E4f1.10.tsv http://dbarchive.biosciencedbc.jp/kyushu-u/mm9/colo/E4f1.Embryonic_fibr

  1. Structural changes and imaging signatures of acoustically sensitive microcapsules under ultrasound.

    Science.gov (United States)

    Sridhar-Keralapura, Mallika; Thirumalai, Shruthi; Mobed-Miremadi, Maryam

    2013-07-01

    The ultrasound drug delivery field is actively designing new agents that would obviate the problems of just using microbubbles for drug delivery. Microbubbles have very short circulation time (minutes), low payload and large size (2-10μm), all of these aspects are not ideal for systemic drug delivery. However, microbubble carriers provide excellent image contrast and their use for image guidance can be exploited. In this paper, we suggest an alternative approach by developing acoustically sensitive microcapsule reservoirs that have future applications for treating large ischemic tumors through intratumoral therapy. We call these agents Acoustically Sensitized Microcapsules (ASMs) and these are not planned for the circulation. ASMs are very simple in their formulation, robust and reproducible. They have been designed to offer high payload (because of their large size), be acoustically sensitive and reactive (because of the Ultrasound Contrast Agents (UCAs) encapsulated) and mechanically robust for future injections/implantations within tumors. We describe three different aspects - (1) effect of therapeutic ultrasound; (2) mechanical properties and (3) imaging signatures of these agents. Under therapeutic ultrasound, the formation of a cavitational bubble was seen prior to rupture. The time to rupture was size dependent. Size dependency was also seen when measuring mechanical properties of these ASMs. % Alginate and permeability also affected the Young's modulus estimates. For study of imaging signatures of these agents, we show six schemes. For example, with harmonic imaging, tissue phantoms and controls did not generate higher harmonic components. Only ASM phantoms created a harmonic signal, whose sensitivity increased with applied acoustic pressure. Future work includes developing schemes combining both sonication and imaging to help detect ASMs before, during and after release of drug substance. Copyright © 2013 Elsevier B.V. All rights reserved.

  2. Three dimensional full-wave nonlinear acoustic simulations: Applications to ultrasound imaging

    Energy Technology Data Exchange (ETDEWEB)

    Pinton, Gianmarco [Joint Department of Biomedical Engineering, University of North Carolina - North Carolina State University, 348 Taylor Hall, Chapel Hill, NC 27599, USA gfp@unc.edu (United States)

    2015-10-28

    Characterization of acoustic waves that propagate nonlinearly in an inhomogeneous medium has significant applications to diagnostic and therapeutic ultrasound. The generation of an ultrasound image of human tissue is based on the complex physics of acoustic wave propagation: diffraction, reflection, scattering, frequency dependent attenuation, and nonlinearity. The nonlinearity of wave propagation is used to the advantage of diagnostic scanners that use the harmonic components of the ultrasonic signal to improve the resolution and penetration of clinical scanners. One approach to simulating ultrasound images is to make approximations that can reduce the physics to systems that have a low computational cost. Here a maximalist approach is taken and the full three dimensional wave physics is simulated with finite differences. This paper demonstrates how finite difference simulations for the nonlinear acoustic wave equation can be used to generate physically realistic two and three dimensional ultrasound images anywhere in the body. A specific intercostal liver imaging scenario for two cases: with the ribs in place, and with the ribs removed. This configuration provides an imaging scenario that cannot be performed in vivo but that can test the influence of the ribs on image quality. Several imaging properties are studied, in particular the beamplots, the spatial coherence at the transducer surface, the distributed phase aberration, and the lesion detectability for imaging at the fundamental and harmonic frequencies. The results indicate, counterintuitively, that at the fundamental frequency the beamplot improves due to the apodization effect of the ribs but at the same time there is more degradation from reverberation clutter. At the harmonic frequency there is significantly less improvement in the beamplot and also significantly less degradation from reverberation. It is shown that even though simulating the full propagation physics is computationally challenging it

  3. Synthetic aperture acoustic imaging of canonical targets with a 2-15 kHz linear FM chirp

    Science.gov (United States)

    Vignola, Joseph F.; Judge, John A.; Good, Chelsea E.; Bishop, Steven S.; Gugino, Peter M.; Soumekh, Mehrdad

    2011-06-01

    Synthetic aperture image reconstruction applied to outdoor acoustic recordings is presented. Acoustic imaging is an alternate method having several military relevant advantages such as being immune to RF jamming, superior spatial resolution, capable of standoff side and forward-looking scanning, and relatively low cost, weight and size when compared to 0.5 - 3 GHz ground penetrating radar technologies. Synthetic aperture acoustic imaging is similar to synthetic aperture radar, but more akin to synthetic aperture sonar technologies owing to the nature of longitudinal or compressive wave propagation in the surrounding acoustic medium. The system's transceiver is a quasi mono-static microphone and audio speaker pair mounted on a rail 5meters in length. Received data sampling rate is 80 kHz with a 2- 15 kHz Linear Frequency Modulated (LFM) chirp, with a pulse repetition frequency (PRF) of 10 Hz and an inter-pulse period (IPP) of 50 milliseconds. Targets are positioned within the acoustic scene at slant range of two to ten meters on grass, dirt or gravel surfaces, and with and without intervening metallic chain link fencing. Acoustic image reconstruction results in means for literal interpretation and quantifiable analyses. A rudimentary technique characterizes acoustic scatter at the ground surfaces. Targets within the acoustic scene are first digitally spotlighted and further processed, providing frequency and aspect angle dependent signature information.

  4. Observations of Brine Pool Surface Characteristics and Internal Structure Through Remote Acoustic and Structured Light Imaging

    Science.gov (United States)

    Smart, C.; Roman, C.; Michel, A.; Wankel, S. D.

    2015-12-01

    Observations and analysis of the surface characteristics and internal structure of deep-sea brine pools are currently limited to discrete in-situ observations. Complementary acoustic and structured light imaging sensors mounted on a remotely operated vehicle (ROV) have demonstrated the ability systematically detect variations in surface characteristics of a brine pool, reveal internal stratification and detect areas of active hydrocarbon activity. The presented visual and acoustic sensors combined with a stereo camera pair are mounted on the 4000m rated ROV Hercules (Ocean Exploration Trust). These three independent sensors operate simultaneously from a typical 3m altitude resulting in visual and bathymetric maps with sub-centimeter resolution. Applying this imaging technology to 2014 and 2015 brine pool surveys in the Gulf of Mexico revealed acoustic and visual anomalies due to the density changes inherent in the brine. Such distinct changes in acoustic impedance allowed the high frequency 1350KHz multibeam sonar to detect multiple interfaces. For instance, distinct acoustic reflections were observed at 3m and 5.5m below the vehicle. Subsequent verification using a CDT and lead line indicated the acoustic return from the brine surface was the signal at 3m, while a thicker muddy and more saline interface occurred at 5.5m, the bottom of the brine pool was not located but is assumed to be deeper than 15m. The multibeam is also capable of remotely detecting emitted gas bubbles within the brine pool, indicative of active hydrocarbon seeps. Bubbles associated with these seeps were not consistently visible above the brine while using the HD camera on the ROV. Additionally, while imaging the surface of brine pool the structured light sheet laser became diffuse, refracting across the main interface. Analysis of this refraction combined with varying acoustic returns allow for systematic and remote detection of the density, stratification and activity levels within and

  5. Near-Field Imaging with Sound: An Acoustic STM Model

    Science.gov (United States)

    Euler, Manfred

    2012-01-01

    The invention of scanning tunneling microscopy (STM) 30 years ago opened up a visual window to the nano-world and sparked off a bunch of new methods for investigating and controlling matter and its transformations at the atomic and molecular level. However, an adequate theoretical understanding of the method is demanding; STM images can be…

  6. Contrast Enhancement for Thermal Acoustic Breast Cancer Imaging via Resonant Stimulation

    Science.gov (United States)

    2010-03-01

    Amplitude distortion is mainly due to the interferences caused by multipath, which is inevitable in the heterogeneous medium: refraction occurs due to...resonance imaging (MRI), has improved the ability to visualize and accurately locate the breast tumor without the need for surgery [7]. This has led to...that the temperature rise is about 0.1 mK and the acoustic pressure change is only about 100 Pa in the microwave- induced TAI system. The shock

  7. Improvement of the imaging of moving acoustic sources by the knowledge of their motion

    Science.gov (United States)

    Hay, J.

    1981-03-01

    An analytical and experimental study is presented showing that, due to a more precise definition of nonstationary noises of a certain class, and to the preprocessing of microphone signals (termed 'coherent dedopplerization'), one can obtain acoustic imaging for sources whose velocity is greater than may be processed by conventional methods without the generation of blurrs of the same order as the antenna field. A useful application of these techniques would be to two-dimensional antennas.

  8. Underwater Acoustic Matched Field Imaging Based on Compressed Sensing

    Directory of Open Access Journals (Sweden)

    Huichen Yan

    2015-10-01

    Full Text Available Matched field processing (MFP is an effective method for underwater target imaging and localizing, but its performance is not guaranteed due to the nonuniqueness and instability problems caused by the underdetermined essence of MFP. By exploiting the sparsity of the targets in an imaging area, this paper proposes a compressive sensing MFP (CS-MFP model from wave propagation theory by using randomly deployed sensors. In addition, the model’s recovery performance is investigated by exploring the lower bounds of the coherence parameter of the CS dictionary. Furthermore, this paper analyzes the robustness of CS-MFP with respect to the displacement of the sensors. Subsequently, a coherence-excluding coherence optimized orthogonal matching pursuit (CCOOMP algorithm is proposed to overcome the high coherent dictionary problem in special cases. Finally, some numerical experiments are provided to demonstrate the effectiveness of the proposed CS-MFP method.

  9. Frequency-space prediction filtering for acoustic clutter and random noise attenuation in ultrasound imaging

    Science.gov (United States)

    Shin, Junseob; Huang, Lianjie

    2016-04-01

    Frequency-space prediction filtering (FXPF), also known as FX deconvolution, is a technique originally developed for random noise attenuation in seismic imaging. FXPF attempts to reduce random noise in seismic data by modeling only real signals that appear as linear or quasilinear events in the aperture domain. In medical ultrasound imaging, channel radio frequency (RF) signals from the main lobe appear as horizontal events after receive delays are applied while acoustic clutter signals from off-axis scatterers and electronic noise do not. Therefore, FXPF is suitable for preserving only the main-lobe signals and attenuating the unwanted contributions from clutter and random noise in medical ultrasound imaging. We adapt FXPF to ultrasound imaging, and evaluate its performance using simulated data sets from a point target and an anechoic cyst. Our simulation results show that using only 5 iterations of FXPF achieves contrast-to-noise ratio (CNR) improvements of 67 % in a simulated noise-free anechoic cyst and 228 % in a simulated anechoic cyst contaminated with random noise of 15 dB signal-to-noise ratio (SNR). Our findings suggest that ultrasound imaging with FXPF attenuates contributions from both acoustic clutter and random noise and therefore, FXPF has great potential to improve ultrasound image contrast for better visualization of important anatomical structures and detection of diseased conditions.

  10. Determining anisotropic conductivity using diffusion tensor imaging data in magneto-acoustic tomography with magnetic induction

    Science.gov (United States)

    Ammari, Habib; Qiu, Lingyun; Santosa, Fadil; Zhang, Wenlong

    2017-12-01

    In this paper we present a mathematical and numerical framework for a procedure of imaging anisotropic electrical conductivity tensor by integrating magneto-acoutic tomography with data acquired from diffusion tensor imaging. Magneto-acoustic tomography with magnetic induction (MAT-MI) is a hybrid, non-invasive medical imaging technique to produce conductivity images with improved spatial resolution and accuracy. Diffusion tensor imaging (DTI) is also a non-invasive technique for characterizing the diffusion properties of water molecules in tissues. We propose a model for anisotropic conductivity in which the conductivity is proportional to the diffusion tensor. Under this assumption, we propose an optimal control approach for reconstructing the anisotropic electrical conductivity tensor. We prove convergence and Lipschitz type stability of the algorithm and present numerical examples to illustrate its accuracy and feasibility.

  11. Invariant correlation filter with linear phase coefficient holographic realization in 4-F correlator

    Science.gov (United States)

    Evtikhiev, Nickolay N.; Starikov, Sergey N.; Shaulskiy, Dmitriy V.; Starikov, Rostislav S.; Zlokazov, Evgeny Yu.

    2011-06-01

    Realization of distortion invariant correlation filters in optical image correlators open possibilities for object identification with remarkably high computational capabilities. Application of the linear phase coefficient composite filter (LPCCF) is attractive for recognition of binary edged images. We use methods of digital holographic synthesis to realize LPCCF in a coherent 4-F correlator as a computer-generated amplitude holographic filter. A high resolution spatial light modulator (SLM) has to be implemented for such a filter representation. Transparency limitations of high frame rate and high resolution SLM's and its effect on recognition performance of holographic filter in the 4-F correlator are discussed in the given paper.

  12. Passive element enriched photoacoustic computed tomography (PER PACT) for simultaneous imaging of acoustic propagation properties and light absorption

    NARCIS (Netherlands)

    Jose, Jithin; Jose, J.; Willemink, Rene; Willemink, Rene G.H.; Resink, Steffen; Piras, D.; van Hespen, Johannes C.G.; van Hespen, J.C.G.; Slump, Cornelis H.; Steenbergen, Wiendelt; van Leeuwen, Ton; Manohar, Srirang

    2011-01-01

    We present a ‘hybrid’ imaging approach which can image both light absorption properties and acoustic transmission properties of an object in a two-dimensional slice using a computed tomography (CT) photoacoustic imager. The ultrasound transmission measurement method uses a strong optical absorber of

  13. Passive element enriched photoacoustic computed tomography (PER PACT) for simultaneous imaging of acoustic propagation properties and light absorption

    NARCIS (Netherlands)

    Jose, J.; Willemink, R.G.H.; Resink, S.; Piras, D.; van Hespen, J.C.G.; Slump, C.H.; van Steenbergen, W.; van Leeuwen, T.G.; Manohar, S.

    2011-01-01

    We present a 'hybrid' imaging approach which can image both light absorption properties and acoustic transmission properties of an object in a two-dimensional slice using a computed tomography (CT) photoacoustic imager. The ultrasound transmission measurement method uses a strong optical absorber of

  14. Estimation of fracture roughness from the acoustic borehole televiewer image

    Energy Technology Data Exchange (ETDEWEB)

    Bae, Dae Soek; Kim, Chun Soo; Kim, Kyung Soo; Park, Byung Yoon; Koh, Yong Kweon

    2000-12-01

    Estimation of fracture roughness - as one of the basic hydraulic fracture parameters - is very important in assessing ground water flow described by using discrete fracture network modeling. Former manual estimation of the roughness for each fracture surface of drill cores is above all a tedious, time-consuming work and will often cause some ambiguities of roughness interpretation partly due to the subjective judgements of observers, and partly due to the measuring procedure itself. However, recently, indebt to the highly reliable Televiewer data for the fracture discrimination, it has led to a guess to develop a relationship between the traditional roughness method based on a linear profiles and the method from the Televiewer image based on a ellipsoidal profile. Hence, the aim of this work is to develop an automatic evaluation algorithm for measuring the roughness from the Televiewer images. A highly reliable software named 'FRAFA' has been developed and realized to the extent that its utility merits. In the developing procedure, various problems - such as the examination of a new base line(ellipsoidal) for measuring the unevenness of fracture, the elimination of overlapping fracture signatures or noise, the wavelet estimation according to the type of fractures and the digitalization of roughness etc. - were considered. With these consideration in mind, the newly devised algorithm for the estimation of roughness curves showed a great potential not only for avoiding ambiguities of roughness interpretation but also for the judgement of roughness classification.

  15. A comparison of traffic estimates of nocturnal flying animals using radar, thermal imaging, and acoustic recording.

    Science.gov (United States)

    Horton, Kyle G; Shriver, W Gregory; Buler, Jeffrey J

    2015-03-01

    There are several remote-sensing tools readily available for the study of nocturnally flying animals (e.g., migrating birds), each possessing unique measurement biases. We used three tools (weather surveillance radar, thermal infrared camera, and acoustic recorder) to measure temporal and spatial patterns of nocturnal traffic estimates of flying animals during the spring and fall of 2011 and 2012 in Lewes, Delaware, USA. Our objective was to compare measures among different technologies to better understand their animal detection biases. For radar and thermal imaging, the greatest observed traffic rate tended to occur at, or shortly after, evening twilight, whereas for the acoustic recorder, peak bird flight-calling activity was observed just prior to morning twilight. Comparing traffic rates during the night for all seasons, we found that mean nightly correlations between acoustics and the other two tools were weakly correlated (thermal infrared camera and acoustics, r = 0.004 ± 0.04 SE, n = 100 nights; radar and acoustics, r = 0.14 ± 0.04 SE, n = 101 nights), but highly variable on an individual nightly basis (range = -0.84 to 0.92, range = -0.73 to 0.94). The mean nightly correlations between traffic rates estimated by radar and by thermal infrared camera during the night were more strongly positively correlated (r = 0.39 ± 0.04 SE, n = 125 nights), but also were highly variable for individual nights (range = -0.76 to 0.98). Through comparison with radar data among numerous height intervals, we determined that flying animal height above the ground influenced thermal imaging positively and flight call detections negatively. Moreover, thermal imaging detections decreased with the presence of cloud cover and increased with mean ground flight speed of animals, whereas acoustic detections showed no relationship with cloud cover presence but did decrease with increased flight speed. We found sampling methods to be positively correlated when comparing mean nightly

  16. [Preliminary design for a VI system combining the voice acoustic analyzing and glottal image analyzing].

    Science.gov (United States)

    Pan, Yan; Liu, Yan; Cai, Xiaolan; Li, Qiao; Meng, Yan; Xu, Xin; Sun, Wenhong; Zhang, Yuhua; Li, Xin; Qi, Yan

    2008-04-01

    This work is directed at developing a virtual instrument system as an accessorial diagnostic instrument for laryngeal diseases. Programmed with LabWindows/CVI, the system combines the voice acoustic analyzing function with the glottal image measuring function. The voice acoustic analyzing system can sample, store and replay vocal signals; can extract and analyze parameters, including fundamental frequency (F0), frequency perturbation quotient (FPQ), amplitude perturbation quotient(APQ), harmonics-to-noise ratio (HNR), jitter frequency (JF), Shimmer; and can do 3D sound graph analysis. The glottal image analyzing system can sample and store the image observed by the laryngostroboscope; can display any phase in one cycle of the vibration of the vocal cords or a slow and continuous movement of vibrating vocal cords; can snap and save the diagnostic frame of image; and can extract the parameters of the image such as the length and area of the glottis, the length and area of the vocal cords and the diseased part.

  17. Spectroscopic study of the interaction of Nd{sup +3} with amino acids: phenomenological 4f-4f intensity parameters

    Energy Technology Data Exchange (ETDEWEB)

    Jerico, Soraya; Carubelli, Celia R.; Massabni, Ana M.G.; Stucchi, Elizabeth B.; Leite, Sergio R. de A. [UNESP, Araraquara, SP (Brazil). Inst. de Quimica; Malta, Oscar [Pernambuco Univ., Recife, PE (Brazil). Dept. de Quimica Fundamental

    1998-10-01

    We have studied behaviour of the phenomenological 4f-4f intensity parameters in compounds of the Nd{sup 3+} ion with glycine, L-aspartic acid, L-glutamic acid, L-histidine, DL-malic acid and Aspartame{sup TM} in aqueous solution, as function of the pK values and partial charges on the oxygens of the carboxylate groups of these molecules. The results are discussed and qualitatively interpreted in terms of the forced electric dipole and dynamic coupling mechanisms of the 4f-4f intensities, thus indicating that the forced electric dipole mechanism is dominant. (author)

  18. Imaging of heart acoustic based on the sub-space methods using a microphone array.

    Science.gov (United States)

    Moghaddasi, Hanie; Almasganj, Farshad; Zoroufian, Arezoo

    2017-07-01

    Heart disease is one of the leading causes of death around the world. Phonocardiogram (PCG) is an important bio-signal which represents the acoustic activity of heart, typically without any spatiotemporal information of the involved acoustic sources. The aim of this study is to analyze the PCG by employing a microphone array by which the heart internal sound sources could be localized, too. In this paper, it is intended to propose a modality by which the locations of the active sources in the heart could also be investigated, during a cardiac cycle. In this way, a microphone array with six microphones is employed as the recording set up to be put on the human chest. In the following, the Group Delay MUSIC algorithm which is a sub-space based localization method is used to estimate the location of the heart sources in different phases of the PCG. We achieved to 0.14cm mean error for the sources of first heart sound (S1) simulator and 0.21cm mean error for the sources of second heart sound (S2) simulator with Group Delay MUSIC algorithm. The acoustical diagrams created for human subjects show distinct patterns in various phases of the cardiac cycles such as the first and second heart sounds. Moreover, the evaluated source locations for the heart valves are matched with the ones that are obtained via the 4-dimensional (4D) echocardiography applied, to a real human case. Imaging of heart acoustic map presents a new outlook to indicate the acoustic properties of cardiovascular system and disorders of valves and thereby, in the future, could be used as a new diagnostic tool. Copyright © 2017. Published by Elsevier B.V.

  19. Spatial distribution of macroalgae along the shores of Kongsfjorden (West Spitsbergen using acoustic imaging

    Directory of Open Access Journals (Sweden)

    Kruss Aleksandra

    2017-06-01

    Full Text Available The identification of macroalgal beds is a crucial component for the description of fjord ecosystems. Direct, biological sampling is still the most popular investigation technique but acoustic methods are becoming increasingly recognized as a very efficient tool for the assessment of benthic communities. In 2007 we carried out the first acoustic survey of the littoral areas in Kongsfjorden. A 2.68 km2 area comprised within a 12.40 km2 euphotic zone was mapped along the fjord’s coast using single- and multi-beam echosounders. The singlebeam echosounder (SBES proved to be a very efficient and reliable tool for macroalgae detection in Arctic conditions. The multibeam echosounder (MBES was very useful in extending the SBES survey range, even though it’s ability in discriminating benthic communities was limited. The final result of our investigation is a map of the macroalgae distribution around the fjord, showing 39% macroalgae coverage (1.09 km2 of investigated area between isobaths -0.70 m and -30 m. Zonation analysis showed that most of the studied macroalgae areas occur up to 15 m depth (93%. These results were confirmed by biological sampling and observation in key areas. The potential of acoustic imaging of macrophytes, and a proposed methodology for the processing of acoustic data, are presented in this paper along with preliminary studies on the acoustic reflectivity of macroalgae, also highlighting differences among species. These results can be applied to future monitoring of the evolution of kelp beds in different areas of the Arctic, and in the rest of the world.

  20. Bond-selective photoacoustic imaging by converting molecular vibration into acoustic waves

    Directory of Open Access Journals (Sweden)

    Jie Hui

    2016-03-01

    Full Text Available The quantized vibration of chemical bonds provides a way of detecting specific molecules in a complex tissue environment. Unlike pure optical methods, for which imaging depth is limited to a few hundred micrometers by significant optical scattering, photoacoustic detection of vibrational absorption breaks through the optical diffusion limit by taking advantage of diffused photons and weak acoustic scattering. Key features of this method include both high scalability of imaging depth from a few millimeters to a few centimeters and chemical bond selectivity as a novel contrast mechanism for photoacoustic imaging. Its biomedical applications spans detection of white matter loss and regeneration, assessment of breast tumor margins, and diagnosis of vulnerable atherosclerotic plaques. This review provides an overview of the recent advances made in vibration-based photoacoustic imaging and various biomedical applications enabled by this new technology.

  1. Sensing the delivery and endocytosis of nanoparticles using magneto-photo-acoustic imaging

    Directory of Open Access Journals (Sweden)

    M. Qu

    2015-09-01

    Full Text Available Many biomedical applications necessitate a targeted intracellular delivery of the nanomaterial to specific cells. Therefore, a non-invasive and reliable imaging tool is required to detect both the delivery and cellular endocytosis of the nanoparticles. Herein, we demonstrate that magneto-photo-acoustic (MPA imaging can be used to monitor the delivery and to identify endocytosis of magnetic and optically absorbing nanoparticles. The relationship between photoacoustic (PA and magneto-motive ultrasound (MMUS signals from the in vitro samples were analyzed to identify the delivery and endocytosis of nanoparticles. The results indicated that during the delivery of nanoparticles to the vicinity of the cells, both PA and MMUS signals are almost linearly proportional. However, accumulation of nanoparticles within the cells leads to nonlinear MMUS-PA relationship, due to non-linear MMUS signal amplification. Therefore, through longitudinal MPA imaging, it is possible to monitor the delivery of nanoparticles and identify the endocytosis of the nanoparticles by living cells.

  2. Sensing the delivery and endocytosis of nanoparticles using magneto-photo-acoustic imaging

    Science.gov (United States)

    Qu, M.; Mehrmohammadi, M.; Emelianov, S.Y.

    2015-01-01

    Many biomedical applications necessitate a targeted intracellular delivery of the nanomaterial to specific cells. Therefore, a non-invasive and reliable imaging tool is required to detect both the delivery and cellular endocytosis of the nanoparticles. Herein, we demonstrate that magneto-photo-acoustic (MPA) imaging can be used to monitor the delivery and to identify endocytosis of magnetic and optically absorbing nanoparticles. The relationship between photoacoustic (PA) and magneto-motive ultrasound (MMUS) signals from the in vitro samples were analyzed to identify the delivery and endocytosis of nanoparticles. The results indicated that during the delivery of nanoparticles to the vicinity of the cells, both PA and MMUS signals are almost linearly proportional. However, accumulation of nanoparticles within the cells leads to nonlinear MMUS-PA relationship, due to non-linear MMUS signal amplification. Therefore, through longitudinal MPA imaging, it is possible to monitor the delivery of nanoparticles and identify the endocytosis of the nanoparticles by living cells. PMID:26640773

  3. Acoustic property reconstruction of a neonate Yangtze finless porpoise's (Neophocaena asiaeorientalis) head based on CT imaging.

    Science.gov (United States)

    Wei, Chong; Wang, Zhitao; Song, Zhongchang; Wang, Kexiong; Wang, Ding; Au, Whitlow W L; Zhang, Yu

    2015-01-01

    The reconstruction of the acoustic properties of a neonate finless porpoise's head was performed using X-ray computed tomography (CT). The head of the deceased neonate porpoise was also segmented across the body axis and cut into slices. The averaged sound velocity and density were measured, and the Hounsfield units (HU) of the corresponding slices were obtained from computed tomography scanning. A regression analysis was employed to show the linear relationships between the Hounsfield unit and both sound velocity and density of samples. Furthermore, the CT imaging data were used to compare the HU value, sound velocity, density and acoustic characteristic impedance of the main tissues in the porpoise's head. The results showed that the linear relationships between HU and both sound velocity and density were qualitatively consistent with previous studies on Indo-pacific humpback dolphins and Cuvier's beaked whales. However, there was no significant increase of the sound velocity and acoustic impedance from the inner core to the outer layer in this neonate finless porpoise's melon.

  4. Prediction of the acoustical performance of enclosures using a hybrid statistical energy analysis: image source model.

    Science.gov (United States)

    Sgard, Franck; Nelisse, Hugues; Atalla, Noureddine; Amedin, Celse Kafui; Oddo, Remy

    2010-02-01

    Enclosures are commonly used to reduce the sound exposure of workers to the noise radiated by machinery. Some acoustic predictive tools ranging from simple analytical tools to sophisticated numerical deterministic models are available to estimate the enclosure acoustical performance. However, simple analytical models are usually valid in limited frequency ranges because of underlying assumptions whereas numerical models are commonly limited to low frequencies. This paper presents a general and simple model for predicting the acoustic performance of large free-standing enclosures which is capable of taking into account the complexity of the enclosure configuration and covering a large frequency range. It is based on the statistical energy analysis (SEA) framework. The sound field inside the enclosure is calculated using the method of image sources. Sound transmission across the various elements of the enclosure is considered in the SEA formalism. The model is evaluated by comparison with existing methods and experimental results. The effect of several parameters such as enclosure geometry, panel materials, presence of noise control treatments, location of the source inside the enclosure, and presence of an opening has been investigated. The comparisons between the model and the experimental results show a good agreement for most of the tested configurations.

  5. Time domain localization technique with sparsity constraint for imaging acoustic sources

    Science.gov (United States)

    Padois, Thomas; Doutres, Olivier; Sgard, Franck; Berry, Alain

    2017-09-01

    This paper addresses source localization technique in time domain for broadband acoustic sources. The objective is to accurately and quickly detect the position and amplitude of noise sources in workplaces in order to propose adequate noise control options and prevent workers hearing loss or safety risk. First, the generalized cross correlation associated with a spherical microphone array is used to generate an initial noise source map. Then a linear inverse problem is defined to improve this initial map. Commonly, the linear inverse problem is solved with an l2 -regularization. In this study, two sparsity constraints are used to solve the inverse problem, the orthogonal matching pursuit and the truncated Newton interior-point method. Synthetic data are used to highlight the performances of the technique. High resolution imaging is achieved for various acoustic sources configurations. Moreover, the amplitudes of the acoustic sources are correctly estimated. A comparison of computation times shows that the technique is compatible with quasi real-time generation of noise source maps. Finally, the technique is tested with real data.

  6. Sparsity-based acoustic inversion in cross-sectional multiscale optoacoustic imaging

    Energy Technology Data Exchange (ETDEWEB)

    Han, Yiyong; Tzoumas, Stratis; Nunes, Antonio; Ntziachristos, Vasilis [Institute for Biological and Medical Imaging, Technische Universitaet Muenchen and Helmholtz Zentrum Muenchen, Ingoldstaedter Landstrasse 1, Neuherberg D-85764 (Germany); Rosenthal, Amir, E-mail: amir.r@ee.technion.ac.il [Institute for Biological and Medical Imaging, Technische Universitaet Muenchen and Helmholtz Zentrum Muenchen, Ingoldstaedter Landstrasse 1, Neuherberg D-85764, Germany and Department of Electrical Engineering, Technion–Israel Institute of Technology, Haifa 32000 (Israel)

    2015-09-15

    Purpose: With recent advancement in hardware of optoacoustic imaging systems, highly detailed cross-sectional images may be acquired at a single laser shot, thus eliminating motion artifacts. Nonetheless, other sources of artifacts remain due to signal distortion or out-of-plane signals. The purpose of image reconstruction algorithms is to obtain the most accurate images from noisy, distorted projection data. Methods: In this paper, the authors use the model-based approach for acoustic inversion, combined with a sparsity-based inversion procedure. Specifically, a cost function is used that includes the L1 norm of the image in sparse representation and a total variation (TV) term. The optimization problem is solved by a numerically efficient implementation of a nonlinear gradient descent algorithm. TV–L1 model-based inversion is tested in the cross section geometry for numerically generated data as well as for in vivo experimental data from an adult mouse. Results: In all cases, model-based TV–L1 inversion showed a better performance over the conventional Tikhonov regularization, TV inversion, and L1 inversion. In the numerical examples, the images reconstructed with TV–L1 inversion were quantitatively more similar to the originating images. In the experimental examples, TV–L1 inversion yielded sharper images and weaker streak artifact. Conclusions: The results herein show that TV–L1 inversion is capable of improving the quality of highly detailed, multiscale optoacoustic images obtained in vivo using cross-sectional imaging systems. As a result of its high fidelity, model-based TV–L1 inversion may be considered as the new standard for image reconstruction in cross-sectional imaging.

  7. [Quantification and improvement of speech transmission performance using headphones in acoustic stimulated functional magnetic resonance imaging].

    Science.gov (United States)

    Yamamura, Ken ichiro; Takatsu, Yasuo; Miyati, Tosiaki; Kimura, Tetsuya

    2014-10-01

    Functional magnetic resonance imaging (fMRI) has made a major contribution to the understanding of higher brain function, but fMRI with auditory stimulation, used in the planning of brain tumor surgery, is often inaccurate because there is a risk that the sounds used in the trial may not be correctly transmitted to the subjects due to acoustic noise. This prompted us to devise a method of digitizing sound transmission ability from the accuracy rate of 67 syllables, classified into three types. We evaluated this with and without acoustic noise during imaging. We also improved the structure of the headphones and compared their sound transmission ability with that of conventional headphones attached to an MRI device (a GE Signa HDxt 3.0 T). We calculated and compared the sound transmission ability of the conventional headphones with that of the improved model. The 95 percent upper confidence limit (UCL) was used as the threshold for accuracy rate of hearing for both headphone models. There was a statistically significant difference between the conventional model and the improved model during imaging (p < 0.01). The rate of accuracy of the improved model was 16 percent higher. 29 and 22 syllables were accurate at a 95% UCL in the improved model and the conventional model, respectively. This study revealed the evaluation system used in this study to be useful for correctly identifying syllables during fMRI.

  8. Imaging of Acoustically Coupled Oscillations Due to Flow Past a Shallow Cavity: Effect of Cavity Length Scale

    Energy Technology Data Exchange (ETDEWEB)

    P. Oshkai; M. Geveci; D. Rockwell; M. Pollack

    2002-12-12

    Flow-acoustic interactions due to fully turbulent inflow past a shallow axisymmetric cavity mounted in a pipe are investigated using a technique of high-image-density particle image velocimetry in conjunction with unsteady pressure measurements. This imaging leads to patterns of velocity, vorticity, streamline topology, and hydrodynamic contributions to the acoustic power integral. Global instantaneous images, as well as time-averaged images, are evaluated to provide insight into the flow physics during tone generation. Emphasis is on the manner in which the streamwise length scale of the cavity alters the major features of the flow structure. These image-based approaches allow identification of regions of the unsteady shear layer that contribute to the instantaneous hydrodynamic component of the acoustic power, which is necessary to maintain a flow tone. In addition, combined image analysis and pressure measurements allow categorization of the instantaneous flow patterns that are associated with types of time traces and spectra of the fluctuating pressure. In contrast to consideration based solely on pressure spectra, it is demonstrated that locked-on tones may actually exhibit intermittent, non-phase-locked images, apparently due to low damping of the acoustic resonator. Locked-on flow tones (without modulation or intermittency), locked-on flow tones with modulation, and non-locked-on oscillations with short-term, highly coherent fluctuations are defined and represented by selected cases. Depending on which of,these regimes occur, the time-averaged Q (quality)-factor and the dimensionless peak pressure are substantially altered.

  9. Combining passive acoustics and imaging sonar techniques to study sperm whales' foraging strategies.

    Science.gov (United States)

    Giorli, Giacomo; Au, Whitlow W L

    2017-09-01

    Sperm whales forage in the deep ocean, hunting for squid. An innovative approach for the study of sperm whale foraging behavior and habitat selection is reported in this letter. A DIDSON imaging sonar mounted on a profiler with a conductivity, temperature, and depth sensor was used to count and measure potential prey in the deep ocean during sperm whales' acoustical foraging encounters in Hawaii. Preliminary results show how this technique can be applied to the study of deep diving whale foraging and habitat selection. Sperm whales foraged where the density of prey decreased with depth and where the size of prey increased with depth.

  10. Investigating the emotional response to room acoustics: A functional magnetic resonance imaging study.

    Science.gov (United States)

    Lawless, M S; Vigeant, M C

    2015-10-01

    While previous research has demonstrated the powerful influence of pleasant and unpleasant music on emotions, the present study utilizes functional magnetic resonance imaging (fMRI) to assess the positive and negative emotional responses as demonstrated in the brain when listening to music convolved with varying room acoustic conditions. During fMRI scans, subjects rated auralizations created in a simulated concert hall with varying reverberation times. The analysis detected activations in the dorsal striatum, a region associated with anticipation of reward, for two individuals for the highest rated stimulus, though no activations were found for regions associated with negative emotions in any subject.

  11. Ultrasound-Mediated Biophotonic Imaging: A Review of Acousto-Optical Tomography and Photo-Acoustic Tomography

    Directory of Open Access Journals (Sweden)

    Lihong V. Wang

    2004-01-01

    Full Text Available This article reviews two types of ultrasound-mediated biophotonic imaging–acousto-optical tomography (AOT, also called ultrasound-modulated optical tomography and photo-acoustic tomography (PAT, also called opto-acoustic or thermo-acoustic tomography–both of which are based on non-ionizing optical and ultrasonic waves. The goal of these technologies is to combine the contrast advantage of the optical properties and the resolution advantage of ultrasound. In these two technologies, the imaging contrast is based primarily on the optical properties of biological tissues, and the imaging resolution is based primarily on the ultrasonic waves that either are provided externally or produced internally, within the biological tissues. In fact, ultrasonic mediation overcomes both the resolution disadvantage of pure optical imaging in thick tissues and the contrast and speckle disadvantages of pure ultrasonic imaging. In our discussion of AOT, the relationship between modulation depth and acoustic amplitude is clarified. Potential clinical applications of ultrasound-mediated biophotonic imaging include early cancer detection, functional imaging, and molecular imaging.

  12. Acoustic noise in functional magnetic resonance imaging reduces pain unpleasantness ratings.

    Science.gov (United States)

    Boyle, Y; Bentley, D E; Watson, A; Jones, A K P

    2006-07-01

    Functional magnetic resonance imaging (fMRI) is increasingly used in cognitive studies. Unfortunately, the scanner produces acoustic noise during the image acquisition process. Interference from acoustic noise is known to affect auditory, visual and motor processing, raising the possibility that acoustic interference may also modulate processing of other sensory modalities such as pain. With the increasing use of fMRI in the investigation of the mechanisms of pain perception, particularly in relation to attention, this issue has become highly relevant. Pain is a complex experience, composed of sensory-discriminative, affective-motivational and cognitive-evaluative components. The aim of this experiment was to assess the effect of MRI scanner noise, compared to white noise, on the affective (unpleasantness) and the sensory-discriminative (localisation) components of pain. Painful radiant heat from a CO(2) laser was delivered to the skin of the right forearm in 24 healthy volunteers. The volunteers attended to either pain location or pain unpleasantness during three conditions: i) no noise, ii) exposure to MRI scanner noise (85 dB) or iii) exposure to white noise (85 dB). Both MRI scanner noise and white noise significantly reduced unpleasantness ratings (from 5.1 +/- 1.6 in the control condition to 4.7 +/- 1.5 (P = 0.002) and 4.6 +/- 1.6 (P white noise respectively), whereas the ability to localise pain was not significantly affected (from 85.4 +/- 9.2% correct in the control condition to 83.1 +/- 10.3% (P = 0.06) and 83.9 +/- 9.5% (P = 0.27) with MRI scanner and white noise respectively). This phenomenon should be taken into account in the design of fMRI studies into human pain perception.

  13. Direct imaging of delayed magneto-dynamic modes induced by surface acoustic waves.

    Science.gov (United States)

    Foerster, Michael; Macià, Ferran; Statuto, Nahuel; Finizio, Simone; Hernández-Mínguez, Alberto; Lendínez, Sergi; Santos, Paulo V; Fontcuberta, Josep; Hernàndez, Joan Manel; Kläui, Mathias; Aballe, Lucia

    2017-09-01

    The magnetoelastic effect-the change of magnetic properties caused by the elastic deformation of a magnetic material-has been proposed as an alternative approach to magnetic fields for the low-power control of magnetization states of nanoelements since it avoids charge currents, which entail ohmic losses. Here, we have studied the effect of dynamic strain accompanying a surface acoustic wave on magnetic nanostructures in thermal equilibrium. We have developed an experimental technique based on stroboscopic X-ray microscopy that provides a pathway to the quantitative study of strain waves and magnetization at the nanoscale. We have simultaneously imaged the evolution of both strain and magnetization dynamics of nanostructures at the picosecond time scale and found that magnetization modes have a delayed response to the strain modes, adjustable by the magnetic domain configuration. Our results provide fundamental insight into magnetoelastic coupling in nanostructures and have implications for the design of strain-controlled magnetostrictive nano-devices.Understanding the effects of local dynamic strain on magnetization may help the development of magnetic devices. Foerster et al. demonstrate stroboscopic imaging that allows the observation of both strain and magnetization dynamics in nickel when surface acoustic waves are driven in the substrate.

  14. Stress-Induced Fracturing of Reservoir Rocks: Acoustic Monitoring and μCT Image Analysis

    Science.gov (United States)

    Pradhan, Srutarshi; Stroisz, Anna M.; Fjær, Erling; Stenebråten, Jørn F.; Lund, Hans K.; Sønstebø, Eyvind F.

    2015-11-01

    Stress-induced fracturing in reservoir rocks is an important issue for the petroleum industry. While productivity can be enhanced by a controlled fracturing operation, it can trigger borehole instability problems by reactivating existing fractures/faults in a reservoir. However, safe fracturing can improve the quality of operations during CO2 storage, geothermal installation and gas production at and from the reservoir rocks. Therefore, understanding the fracturing behavior of different types of reservoir rocks is a basic need for planning field operations toward these activities. In our study, stress-induced fracturing of rock samples has been monitored by acoustic emission (AE) and post-experiment computer tomography (CT) scans. We have used hollow cylinder cores of sandstones and chalks, which are representatives of reservoir rocks. The fracture-triggering stress has been measured for different rocks and compared with theoretical estimates. The population of AE events shows the location of main fracture arms which is in a good agreement with post-test CT image analysis, and the fracture patterns inside the samples are visualized through 3D image reconstructions. The amplitudes and energies of acoustic events clearly indicate initiation and propagation of the main fractures. Time evolution of the radial strain measured in the fracturing tests will later be compared to model predictions of fracture size.

  15. A NEW, OTHER THAN ACOUSTIC, QUANTIFICATION METHOD FOR ENDOCARDIUM DETECTION IN ECHOCARDIOGRAPHIC IMAGES

    Directory of Open Access Journals (Sweden)

    Leszek Wojnar

    2011-05-01

    Full Text Available A new, semiautomatic algorithm for tracing outlines of endocardium of newborns that are detectable in echocardiographic images is presented. The main advantage of the method proposed is its low sensitivity to operator errors. Moreover, in contrast to the acoustic quantification method (AQ, an analysis of archive and low quality images is available, as well as the traces obtained are smooth and free of artefacts. Thus, the new solution allows for further, fully automatic, quantitative characterization of the shape and size of the ventricle. The results are compared with manual tracings in order to demonstrate the advantage of the newly developed method. Some results from massive research on newborns with various heart defects are also presented.

  16. Optical-resolution photoacoustic imaging through thick tissue with a thin capillary as a dual optical-in acoustic-out waveguide

    CERN Document Server

    Simandoux, Olivier; Gateau, Jerome; Huignard, Jean-Pierre; Moser, Christophe; Psaltis, Demetri; Bossy, Emmanuel

    2015-01-01

    We demonstrate the ability to guide high-frequency photoacoustic waves through thick tissue with a water-filled silica-capillary (150 \\mu m inner diameter and 30 mm long). An optical-resolution photoacoustic image of a 30 \\mu m diameter absorbing nylon thread was obtained by guiding the acoustic waves in the capillary through a 3 cm thick fat layer. The transmission loss through the capillary was about -20 dB, much lower than the -120 dB acoustic attenuation through the fat layer. The overwhelming acoustic attenuation of high-frequency acoustic waves by biological tissue can therefore be avoided by the use of a small footprint capillary acoustic waveguide for remote detection. We finally demonstrate that the capillary can be used as a dual optical-in acoustic-out waveguide, paving the way for the development of minimally invasive optical-resolution photoacoustic endoscopes free of any acoustic or optical elements at their imaging tip.

  17. Green's Function Retrieval and Marchenko Imaging in a Dissipative Acoustic Medium.

    Science.gov (United States)

    Slob, Evert

    2016-04-22

    Single-sided Marchenko equations for Green's function construction and imaging relate the measured reflection response of a lossless heterogeneous medium to an acoustic wave field inside this medium. I derive two sets of single-sided Marchenko equations for the same purpose, each in a heterogeneous medium, with one medium being dissipative and the other a corresponding medium with negative dissipation. Double-sided scattering data of the dissipative medium are required as input to compute the surface reflection response in the corresponding medium with negative dissipation. I show that each set of single-sided Marchenko equations leads to Green's functions with a virtual receiver inside the medium: one exists inside the dissipative medium and one in the medium with negative dissipation. This forms the basis of imaging inside a dissipative heterogeneous medium. I relate the Green's functions to the reflection response inside each medium, from which the image can be constructed. I illustrate the method with a one-dimensional example that shows the image quality. The method has a potentially wide range of imaging applications where the material under test is accessible from two sides.

  18. Interferometric imaging of acoustical phenomena using high-speed polarization camera and 4-step parallel phase-shifting technique

    Science.gov (United States)

    Ishikawa, K.; Yatabe, K.; Ikeda, Y.; Oikawa, Y.; Onuma, T.; Niwa, H.; Yoshii, M.

    2017-02-01

    Imaging of sound aids the understanding of the acoustical phenomena such as propagation, reflection, and diffraction, which is strongly required for various acoustical applications. The imaging of sound is commonly done by using a microphone array, whereas optical methods have recently been interested due to its contactless nature. The optical measurement of sound utilizes the phase modulation of light caused by sound. Since light propagated through a sound field changes its phase as proportional to the sound pressure, optical phase measurement technique can be used for the sound measurement. Several methods including laser Doppler vibrometry and Schlieren method have been proposed for that purpose. However, the sensitivities of the methods become lower as a frequency of sound decreases. In contrast, since the sensitivities of the phase-shifting technique do not depend on the frequencies of sounds, that technique is suitable for the imaging of sounds in the low-frequency range. The principle of imaging of sound using parallel phase-shifting interferometry was reported by the authors (K. Ishikawa et al., Optics Express, 2016). The measurement system consists of a high-speed polarization camera made by Photron Ltd., and a polarization interferometer. This paper reviews the principle briefly and demonstrates the high-speed imaging of acoustical phenomena. The results suggest that the proposed system can be applied to various industrial problems in acoustical engineering.

  19. Role of 4 f electrons in crystallographic and magnetic complexity

    Science.gov (United States)

    Pathak, Arjun K.; Paudyal, Durga; Mudryk, Yaroslav; Pecharsky, Vitalij K.

    2017-08-01

    The functionality of many magnetic materials critically depends on first manipulating and then taking advantage of highly nonlinear changes of properties that occur during phase transformations. Unique to lanthanides, property-defining 4 f electrons are highly localized and, as commonly accepted, play little to no role in chemical bonding. Yet here we demonstrate that the competition between 4 f -electron energy landscapes of Dy (4 f9 ) and Er (4 f11 ) is the key element of the puzzle required to explain complex interplay of magnetic and structural features observed in E r1 -xD yxC o2 , and likely many other mixed lanthanide systems. Unlike the parent binaries—DyC o2 and ErC o2 —E r1 -xD yxC o2 exhibits two successive magnetostructural transitions: a first order at TC, followed by a second order in the ferrimagnetically ordered state. Supported by first-principles calculations, our results offer new opportunities for targeted design of magnetic materials with multiple functionalities, and also provide a critical insight into the role of 4 f electrons in controlling the magnetism and structure of lanthanide intermetallics.

  20. Spatial Prediction Filtering of Acoustic Clutter and Random Noise in Medical Ultrasound Imaging.

    Science.gov (United States)

    Shin, Junseob; Huang, Lianjie

    2017-02-01

    One of the major challenges in array-based medical ultrasound imaging is the image quality degradation caused by sidelobes and off-axis clutter, which is an inherent limitation of the conventional delay-and-sum (DAS) beamforming operating on a finite aperture. Ultrasound image quality is further degraded in imaging applications involving strong tissue attenuation and/or low transmit power. In order to effectively suppress acoustic clutter from off-axis targets and random noise in a robust manner, we introduce in this paper a new adaptive filtering technique called frequency-space (F-X) prediction filtering or FXPF, which was first developed in seismic imaging for random noise attenuation. Seismologists developed FXPF based on the fact that linear and quasilinear events or wavefronts in the time-space (T-X) domain are manifested as a superposition of harmonics in the frequency-space (F-X) domain, which can be predicted using an auto-regressive (AR) model. We describe the FXPF technique as a spectral estimation or a direction-of-arrival problem, and explain why adaptation of this technique into medical ultrasound imaging is beneficial. We apply our new technique to simulated and tissue-mimicking phantom data. Our results demonstrate that FXPF achieves CNR improvements of 26% in simulated noise-free anechoic cyst, 109% in simulated anechoic cyst contaminated with random noise of 15 dB SNR, and 93% for experimental anechoic cyst from a custom-made tissue-mimicking phantom. Our findings suggest that FXPF is an effective technique to enhance ultrasound image contrast and has potential to improve the visualization of clinically important anatomical structures and diagnosis of diseased conditions.

  1. Imaging of human tooth using ultrasound based chirp-coded nonlinear time reversal acoustics.

    Science.gov (United States)

    Dos Santos, Serge; Prevorovsky, Zdenek

    2011-08-01

    Human tooth imaging sonography is investigated experimentally with an acousto-optic noncoupling set-up based on the chirp-coded nonlinear time reversal acoustic concept. The complexity of the tooth internal structure (enamel-dentine interface, cracks between internal tubules) is analyzed by adapting the nonlinear elastic wave spectroscopy (NEWS) with the objective of the tomography of damage. Optimization of excitations using intrinsic symmetries, such as time reversal (TR) invariance, reciprocity, correlation properties are then proposed and implemented experimentally. The proposed medical application of this TR-NEWS approach is implemented on a third molar human tooth and constitutes an alternative of noncoupling echodentography techniques. A 10 MHz bandwidth ultrasonic instrumentation has been developed including a laser vibrometer and a 20 MHz contact piezoelectric transducer. The calibrated chirp-coded TR-NEWS imaging of the tooth is obtained using symmetrized excitations, pre- and post-signal processing, and the highly sensitive 14 bit resolution TR-NEWS instrumentation previously calibrated. Nonlinear signature coming from the symmetry properties is observed experimentally in the tooth using this bi-modal TR-NEWS imaging after and before the focusing induced by the time-compression process. The TR-NEWS polar B-scan of the tooth is described and suggested as a potential application for modern echodentography. It constitutes the basis of the self-consistent harmonic imaging sonography for monitoring cracks propagation in the dentine, responsible of human tooth structural health. Copyright © 2011 Elsevier B.V. All rights reserved.

  2. Ion chemistry in octafluorocyclobutane, c-C 4F 8

    Science.gov (United States)

    Jiao, C. Q.; Garscadden, A.; Haaland, P. D.

    1998-11-01

    Cross-sections for electron impact ionization of octafluorocyclobutane ( c-C 4F 8) have been measured from 10 to 200 eV by Fourier transform mass spectrometry. No parent ion is observed, and over half of the dissociative ionization yields C 2F 4+ and C 3F 5+. Eleven other fluorocarbon cations are produced with smaller cross-sections, giving a total ionization cross-section of (1.6±0.2)×10 -15 cm 2 between 80 and 200 eV. Only CF 2+ and C 2F 3+ react further with the parent molecule to yield C 3F 5+ as the primary product. No evidence of cationic polymerization was found. F - and C 4F 8- are formed by electron attachment at energies below 10 eV, but neither reacts further with c-C 4F 8.

  3. Non-Imaging Acoustical Properties in Monitoring Arteriovenous Hemodialysis Access. A Review

    Directory of Open Access Journals (Sweden)

    Anas Mohd Noor

    2015-12-01

    Full Text Available The limitations of the gold standard angiography technique in arteriovenous access surveillance have opened a gap for researchers to find the best way to monitor this condition with low-cost, non-invasive and continuous bedside monitoring. The phonoangiography technique has been developed prior to these limits. This measurement and monitoring technique, associated with intelligence signal processing, promises better analysis for early detection of hemodialysis access problems, such as stenosis and thrombosis. Some research groups have shown that the phonoangiography technique could identify as many as 20% of vascular diameter changes and also its frequency characteristics due to hemodialysis access problems. The frequency characteristics of these acoustical signals are presented and discussed in detail to understand the association with the stenosis level, blood flows, sensor locations, fundamental frequency bands of normal and abnormal conditions, and also the spectral energy produced. This promising technique could be used in the near future as a tool for pre-diagnosis of arteriovenous access before any further access correction by surgical techniques is required. This paper provides an extensive review of various arteriovenous access monitoring techniques based on non-imaging acoustical properties.

  4. A cross-correlation objective function for least-squares migration and visco-acoustic imaging

    KAUST Repository

    Dutta, Gaurav

    2014-08-05

    Conventional acoustic least-squares migration inverts for a reflectivity image that best matches the amplitudes of the observed data. However, for field data applications, it is not easy to match the recorded amplitudes because of the visco-elastic nature of the earth and inaccuracies in the estimation of source signature and strength at different shot locations. To relax the requirement for strong amplitude matching of least-squares migration, we use a normalized cross-correlation objective function that is only sensitive to the similarity between the predicted and the observed data. Such a normalized cross-correlation objective function is also equivalent to a time-domain phase inversion method where the main emphasis is only on matching the phase of the data rather than the amplitude. Numerical tests on synthetic and field data show that such an objective function can be used as an alternative to visco-acoustic least-squares reverse time migration (Qp-LSRTM) when there is strong attenuation in the subsurface and the estimation of the attenuation parameter Qp is insufficiently accurate.

  5. Comparison of ultrasound B-mode, strain imaging, acoustic radiation force impulse displacement and shear wave velocity imaging using real time clinical breast images

    Science.gov (United States)

    Manickam, Kavitha; Machireddy, Ramasubba Reddy; Raghavan, Bagyam

    2016-04-01

    It has been observed that many pathological process increase the elastic modulus of soft tissue compared to normal. In order to image tissue stiffness using ultrasound, a mechanical compression is applied to tissues of interest and local tissue deformation is measured. Based on the mechanical excitation, ultrasound stiffness imaging methods are classified as compression or strain imaging which is based on external compression and Acoustic Radiation Force Impulse (ARFI) imaging which is based on force generated by focused ultrasound. When ultrasound is focused on tissue, shear wave is generated in lateral direction and shear wave velocity is proportional to stiffness of tissues. The work presented in this paper investigates strain elastography and ARFI imaging in clinical cancer diagnostics using real time patient data. Ultrasound B-mode imaging, strain imaging, ARFI displacement and ARFI shear wave velocity imaging were conducted on 50 patients (31 Benign and 23 malignant categories) using Siemens S2000 machine. True modulus contrast values were calculated from the measured shear wave velocities. For ultrasound B-mode, ARFI displacement imaging and strain imaging, observed image contrast and Contrast to Noise Ratio were calculated for benign and malignant cancers. Observed contrast values were compared based on the true modulus contrast values calculated from shear wave velocity imaging. In addition to that, student unpaired t-test was conducted for all the four techniques and box plots are presented. Results show that, strain imaging is better for malignant cancers whereas ARFI imaging is superior than strain imaging and B-mode for benign lesions representations.

  6. Effect of Genetic Variability in the CYP4F2, CYP4F11, and CYP4F12 Genes on Liver mRNA Levels and Warfarin Response

    Directory of Open Access Journals (Sweden)

    J. E. Zhang

    2017-05-01

    Full Text Available Genetic polymorphisms in the gene encoding cytochrome P450 (CYP 4F2, a vitamin K oxidase, affect stable warfarin dose requirements and time to therapeutic INR. CYP4F2 is part of the CYP4F gene cluster, which is highly polymorphic and exhibits a high degree of linkage disequilibrium, making it difficult to define causal variants. Our objective was to examine the effect of genetic variability in the CYP4F gene cluster on expression of the individual CYP4F genes and warfarin response. mRNA levels of the CYP4F gene cluster were quantified in human liver samples (n = 149 obtained from a well-characterized liver bank and fine mapping of the CYP4F gene cluster encompassing CYP4F2, CYP4F11, and CYP4F12 was performed. Genome-wide association study (GWAS data from a prospective cohort of warfarin-treated patients (n = 711 was also analyzed for genetic variations across the CYP4F gene cluster. In addition, SNP-gene expression in human liver tissues and interactions between CYP4F genes were explored in silico using publicly available data repositories. We found that SNPs in CYP4F2, CYP4F11, and CYP4F12 were associated with mRNA expression in the CYP4F gene cluster. In particular, CYP4F2 rs2108622 was associated with increased CYP4F2 expression while CYP4F11 rs1060467 was associated with decreased CYP4F2 expression. Interestingly, these CYP4F2 and CYP4F11 SNPs showed similar effects with warfarin stable dose where CYP4F11 rs1060467 was associated with a reduction in daily warfarin dose requirement (∼1 mg/day, Pc = 0.017, an effect opposite to that previously reported with CYP4F2 (rs2108622. However, inclusion of either or both of these SNPs in a pharmacogenetic algorithm consisting of age, body mass index (BMI, gender, baseline clotting factor II level, CYP2C9∗2 rs1799853, CYP2C9∗3 rs1057910, and VKORC1 rs9923231 improved warfarin dose variability only by 0.5–0.7% with an improvement in dose prediction accuracy of ∼1–2%. Although there is complex

  7. Application of pulse acoustic microscopy technique for 3D imaging bulk microstructure of carbon fiber-reinforced composites.

    Science.gov (United States)

    Liu, Songping; Guo, Enming; Levin, V M; Liu, Feifei; Petronyuk, Yu S; Zhang, Qianlin

    2006-12-22

    Impulse acoustic microscopy technique is applied for 3D imaging of bulk microstructure of composite materials. Short pulses of focused high-frequency ultrasound have been employed for layer-by-layer imaging of internal microstructure of carbon fiber-reinforced composite (CFRC) laminates. The method provides spatial resolution of 60 microm and in-depth resolution of 80 microm, approximately. Echo signals reflected from structural units--plies, fiber bundles; and microflaws form acoustic images of microstructure at different depth inside samples. The images make it possible to see ply arrays, packing of bundles in plies; binding material distribution over the specimen body. They reveal failure of interply adhesion, buckling of single plies and fiber bundles, internal defoliations and disbonds, voids in the specimen body. The series of successive images offer outstanding possibilities to reconstruct the bulk structure, to estimate local variations of properties, topological and geometrical characteristics of structural components. The imaging technique has been applied to study different types of fiber packing--unidirectional, cross-ply and woven laminates. Mechanisms of ultrasonic contrast for diverse elements in acoustic images of CFRC laminate bulk microstructure and structural defects are discussed.

  8. Acoustic radiation- and streaming-induced microparticle velocities determined by microparticle image velocimetry in an ultrasound symmetry plane

    DEFF Research Database (Denmark)

    Barnkob, Rune; Augustsson, Per; Laurell, Thomas

    2012-01-01

    We present microparticle image velocimetry measurements of suspended microparticles of diameters from 0.6 to 10μm undergoing acoustophoresis in an ultrasound symmetry plane in a microchannel. The motion of the smallest particles is dominated by the Stokes drag from the induced acoustic streaming...

  9. High-Resolution Acoustic-Radiation-Force-Impulse Imaging for Assessing Corneal Sclerosis

    Science.gov (United States)

    Shih, Cho-Chiang; Zhou, Qifa; Shung, K. Kirk

    2013-01-01

    In ophthalmology, detecting the biomechanical properties of the cornea can provide valuable information about various corneal pathologies, including keratoconus and the phototoxic effects of ultraviolet radiation on the cornea. Also, the mechanical properties of the cornea can be used to evaluate the recovery from corneal refractive surgeries. Therefore, noninvasive and high-resolution estimation of the stiffness distribution in the cornea is important in ophthalmic diagnosis. The present study established a method for high-resolution acoustic-radiation-force-impulse (ARFI) imaging based on a dual-frequency confocal transducer in order to obtain a relative stiffness map, which was used to assess corneal sclerosis. An 11-MHz pushing element was used to induce localized displacements of tissue, which were monitored by a 48-MHz imaging element. Since the tissue displacements are directly correlated with the tissue elastic properties, the stiffness distribution in a tiny region of the cornea can be found by a mechanical B/D scan. The experimental system was verified using tissue-mimicking phantoms that included different geometric structures. Ex vivo cornea experiments were carried out using fresh porcine eyeballs. Corneas with localized sclerosis were created artificially by the injection of a formalin solution. The phantom experiments showed that the distributions of stiffness within different phantoms can be recognized clearly using ARFI imaging, and the measured lateral and axial resolutions of this imaging system were 177 and 153 μm, respectively. The ex vivo experimental results from ARFI imaging showed that a tiny region of localized sclerosis in the cornea could be distinguished. All of the obtained results demonstrate that high-resolution ARFI imaging has considerable potential for the clinical diagnosis of corneal sclerosis. PMID:23584258

  10. High-resolution acoustic-radiation-force-impulse imaging for assessing corneal sclerosis.

    Science.gov (United States)

    Shih, Cho-Chiang; Huang, Chih-Chung; Zhou, Qifa; Shung, K Kirk

    2013-07-01

    In ophthalmology, detecting the biomechanical properties of the cornea can provide valuable information about various corneal pathologies, including keratoconus and the phototoxic effects of ultraviolet radiation on the cornea. Also, the mechanical properties of the cornea can be used to evaluate the recovery from corneal refractive surgeries. Therefore, noninvasive and high-resolution estimation of the stiffness distribution in the cornea is important in ophthalmic diagnosis. The present study established a method for high-resolution acoustic-radiation-force-impulse (ARFI) imaging based on a dual-frequency confocal transducer in order to obtain a relative stiffness map, which was used to assess corneal sclerosis. An 11-MHz pushing element was used to induce localized displacements of tissue, which were monitored by a 48-MHz imaging element. Since the tissue displacements are directly correlated with the tissue elastic properties, the stiffness distribution in a tiny region of the cornea can be found by a mechanical B/D scan. The experimental system was verified using tissue-mimicking phantoms that included different geometric structures. Ex vivo cornea experiments were carried out using fresh porcine eyeballs. Corneas with localized sclerosis were created artificially by the injection of a formalin solution. The phantom experiments showed that the distributions of stiffness within different phantoms can be recognized clearly using ARFI imaging, and the measured lateral and axial resolutions of this imaging system were 177 and 153 μ m, respectively. The ex vivo experimental results from ARFI imaging showed that a tiny region of localized sclerosis in the cornea could be distinguished. All of the obtained results demonstrate that high-resolution ARFI imaging has considerable potential for the clinical diagnosis of corneal sclerosis.

  11. Global acoustic daylight imaging in a stratified Earth-like model

    Science.gov (United States)

    de Hoop, Maarten V.; Garnier, Josselin; Sølna, Knut

    2018-01-01

    We present an analysis of acoustic daylight imaging in an Earth-like model assuming a random distribution of noise sources spatially supported in an annulus located away from the surface. We assume a situation with scalar wave propagation and that the measurements are of the wave field at the surface. Then, we obtain a relation between the autocorrelation function of the measurements and the trace of the scattered field generated by an impulsive source localized just below the surface. From this relation it is, for example, clear that the eigenfrequencies can be recovered from the autocorrelation. Moreover, the complete scattering operator can be extracted under the additional assumption that the annulus is close to the surface and has a thickness smaller than the typical wavelength.

  12. Measuring soft tissue elasticity by monitoring surface acoustic waves using image plane digital holography

    Science.gov (United States)

    Li, Shiguang; Oldenburg, Amy L.

    2011-03-01

    The detection of tumors in soft tissues, such as breast cancer, is important to achieve at the earliest stages of the disease to improve patient outcome. Tumors often exhibit a greater elastic modulus compared to normal tissues. In this paper, we report our first study to measure elastic properties of soft tissues by mapping the surface acoustic waves (SAWs) with image plane digital holography. The experimental results show that the SAW velocity is proportional to the square root of elastic modulus over a range from 3.7-122kPa in homogeneous tissue phantoms, consistent with Rayleigh wave theory. This technique also permits detection of the interface of two-layer phantoms 10mm deep under surface and the interface depth by quantifying the SAW dispersion.

  13. Imaging of Acoustically Coupled Oscillations Due to Flow Past a Shallow Cavity: Effect of Cavity Length Scale

    Energy Technology Data Exchange (ETDEWEB)

    P Oshkai; M Geveci; D Rockwell; M Pollack

    2004-05-24

    Flow-acoustic interactions due to fully turbulent inflow past a shallow axisymmetric cavity mounted in a pipe, which give rise to flow tones, are investigated using a technique of high-image-density particle image velocimetry in conjunction with unsteady pressure measurements. This imaging leads to patterns of velocity, vorticity, streamline topology, and hydrodynamic contributions to the acoustic power integral. Global instantaneous images, as well as time-averaged images, are evaluated to provide insight into the flow physics during tone generation. Emphasis is on the manner in which the streamwise length scale of the cavity alters the major features of the flow structure. These image-based approaches allow identification of regions of the unsteady shear layer that contribute to the instantaneous hydrodynamic component of the acoustic power, which is necessary to maintain a flow tone. In addition, combined image analysis and pressure measurements allow categorization of the instantaneous flow patterns that are associated with types of time traces and spectra of the fluctuating pressure. In contrast to consideration based solely on pressure spectra, it is demonstrated that locked-on tones may actually exhibit intermittent, non-phase-locked images, apparently due to low damping of the acoustic resonator. Locked-on flow tones (without modulation or intermittency), locked-on flow tones with modulation, and non-locked-on oscillations with short-term, highly coherent fluctuations are defined and represented by selected cases. Depending on which of these regimes occur, the time-averaged Q (quality)-factor and the dimensionless peak pressure are substantially altered.

  14. Pulse shaping and characterization with a 4f system

    CSIR Research Space (South Africa)

    Botha, N

    2010-10-01

    Full Text Available . 3. References [1] A. M. Weiner, Review of Scientific Instruments, Volume 71, Number 5, p. 1929-1960 [2] M. Cavallari, G.M. Gale, F. Hache, L.I. Pavlov, E. Rousseau, Optics Communication, Volume 114, p. 329 - 332 Fig.1: 4f pulse shaper...

  15. Reproducibility of shear wave velocity measurements by acoustic radiation force impulse imaging of the liver: a study in healthy volunteers.

    Science.gov (United States)

    Guzmán-Aroca, Florentina; Reus, Manuel; Berná-Serna, Juan D; Serrano, Laura; Serrano, Cristina; Gilabert, Amparo; Cepero, Angela

    2011-07-01

    The purposes of this study were to investigate interobserver reproducibility using acoustic radiation force impulse imaging and to develop an acoustic radiation force impulse scoring system. Fifty healthy volunteers with normal liver function test values were selected for the study. Shear wave velocity measurements, expressed in meters per second, were taken in a deep portion of liver segment 6. Two observers with different levels of experience performed the measurements independently and blindly. All of the measurements taken by the 2 observers were valid, even in volunteers with a body mass index of greater than 28 kg/m(2). The results point to very good interobserver reproducibility of shear wave velocity measurements, with an intraclass coefficient correlation of 0.86 (P measurements using the acoustic radiation force impulse technique and a standardized protocol are accurate and reproducible.

  16. Effect of MRI acoustic noise on cerebral fludeoxyglucose uptake in simultaneous MR-PET imaging.

    Science.gov (United States)

    Chonde, Daniel B; Abolmaali, Nasreddin; Arabasz, Grae; Guimaraes, Alexander R; Catana, Ciprian

    2013-05-01

    Integrated scanners capable of simultaneous positron emission tomography (PET) and magnetic resonance imaging (MRI) data acquisition are now available for human use. Although the scanners' manufacturers have made substantial efforts to understand and minimize the mutual electromagnetic interference between the 2 modalities, the potential physiological inference has not been evaluated. In this study, we have studied the influence of the acoustic noise produced by the magnetic resonance (MR) gradients on brain fludeoxyglucose (FDG) uptake in the Siemens MR-BrainPET prototype. Although particular attention was paid to the primary auditory cortex (PAC), a brain-wide analysis was also performed. The effects of the MR on the PET count rate and image quantification were first investigated in phantoms. Next, 10 healthy volunteers underwent 2 simultaneous FDG-PET/MR scans in the supine position with the FDG injection occurring inside the MR-BrainPET, alternating between a "quiet" (control) environment in which no MR sequences were run during the FDG uptake phase (the first 40 minutes after radiotracer administration) and a "noisy" (test) environment in which MR sequences were run for the entire time. Cortical and subcortical regions of interest were derived from the high-resolution morphological MR data using FreeSurfer. The changes in the FDG uptake in the FreeSurfer-derived regions of interest between the 2 conditions were analyzed from parametric and static PET images, and on a voxel-by-voxel basis using SPM8 and FreeSurfer. Only minimal to no electromagnetic interference was observed for most of the MR sequences tested, with a maximum drop in count rate of 1.5% and a maximum change in the measured activity of 1.1% in the corresponding images. The region of interest-based analysis showed statistically significant increases in the right PAC in both the parametric (9.13% [4.73%]) and static (4.18% [2.87%]) images. The SPM8 analysis showed no statistically significant

  17. Magneto acoustic tomography with short pulsed magnetic field for in-vivo imaging of magnetic iron oxide nanoparticles.

    Science.gov (United States)

    Mariappan, Leo; Shao, Qi; Jiang, Chunlan; Yu, Kai; Ashkenazi, Shai; Bischof, John C; He, Bin

    2016-04-01

    Nanoparticles are widely used as contrast and therapeutic agents. As such, imaging modalities that can accurately estimate their distribution in-vivo are actively sought. We present here our method Magneto Acoustic Tomography (MAT), which uses magnetomotive force due to a short pulsed magnetic field to induce ultrasound in the magnetic nanoparticle labeled tissue and estimates an image of the distribution of the nanoparticles in-vivo with ultrasound imaging resolution. In this study, we image the distribution of superparamagnetic iron oxide nanoparticles (IONP) using MAT method. In-vivo imaging was performed on live, nude mice with IONP injected into LNCaP tumors grown subcutaneously within the hind limb of the mice. Our experimental results indicate that the MAT method is capable of imaging the distribution of IONPs in-vivo. Therefore, MAT could become an imaging modality for high resolution reconstruction of MNP distribution in the body. Many magnetic nanoparticles (MNPs) have been used as contrast agents in magnetic resonance imaging. In this study, the authors investigated the use of ultrasound to detect the presence of MNPs by magneto acoustic tomography. In-vivo experiments confirmed the imaging quality of this new approach, which hopefully would provide an alternative method for accurate tumor detection. Copyright © 2015 Elsevier Inc. All rights reserved.

  18. Temperature-dependent differences in the nonlinear acoustic behavior of ultrasound contrast agents revealed by high-speed imaging and bulk acoustics.

    Science.gov (United States)

    Mulvana, Helen; Stride, Eleanor; Tang, Mengxing; Hajnal, Jo V; Eckersley, Robert

    2011-09-01

    Previous work by the authors has established that increasing the temperature of the suspending liquid from 20°C to body temperature has a significant impact on the bulk acoustic properties and stability of an ultrasound contrast agent suspension (SonoVue, Bracco Suisse SA, Manno, Lugano, Switzerland). In this paper the influence of temperature on the nonlinear behavior of microbubbles is investigated, because this is one of the most important parameters in the context of diagnostic imaging. High-speed imaging showed that raising the temperature significantly influences the dynamic behavior of individual microbubbles. At body temperature, microbubbles exhibit greater radial excursion and oscillate less spherically, with a greater incidence of jetting and gas expulsion, and therefore collapse, than they do at room temperature. Bulk acoustics revealed an associated increase in the harmonic content of the scattered signals. These findings emphasize the importance of conducting laboratory studies at body temperature if the results are to be interpreted for in vivo applications. Copyright © 2011 World Federation for Ultrasound in Medicine & Biology. Published by Elsevier Inc. All rights reserved.

  19. Imaging surface acoustic wave dynamics in semiconducting polymers by scanning ultrafast electron microscopy.

    Science.gov (United States)

    Najafi, Ebrahim; Liao, Bolin; Scarborough, Timothy; Zewail, Ahmed

    2018-01-01

    Understanding the mechanical properties of organic semiconductors is essential to their electronic and photovoltaic applications. Despite a large volume of research directed toward elucidating the chemical, physical and electronic properties of these materials, little attention has been directed toward understanding their thermo-mechanical behavior. Here, we report the ultrafast imaging of surface acoustic waves (SAWs) on the surface of the Poly(3-hexylthiophene-2,5-diyl) (P3HT) thin film at the picosecond and nanosecond timescales. We then use these images to measure the propagation velocity of SAWs, which we then employ to determine the Young's modulus of P3HT. We further validate our experimental observation by performing a semi-empirical transient thermoelastic finite element analysis. Our findings demonstrate the potential of ultrafast electron microscopy to not only probe charge carrier dynamics in materials as previously reported, but also to measure their mechanical properties with great accuracy. This is particularly important when in situ characterization of stiffness for thin devices and nanomaterials is required. Copyright © 2017 Elsevier B.V. All rights reserved.

  20. TU-F-CAMPUS-I-04: Head-Only Asymmetric Gradient System Evaluation: ACR Image Quality and Acoustic Noise

    Energy Technology Data Exchange (ETDEWEB)

    Weavers, P; Shu, Y; Tao, S; Bernstein, M [Mayo Clinic, Rochester, Minnesota (United States); Lee, S; Piel, J; Foo, T [GE Global Research, Niskayuna, NY (United States); Mathieu, J-B [GE Healthcare, Florence, SC (Italy)

    2015-06-15

    Purpose: A high-performance head-only magnetic resonance imaging gradient system with an acquisition volume of 26 cm employing an asymmetric design for the transverse coils has been developed. It is able to reach a magnitude of 85 mT/m at a slew rate of 700 T/m/s, but operated at 80 mT/m and 500 T/m/s for this test. A challenge resulting from this asymmetric design is that the gradient nonlinearly exhibits both odd- and even-ordered terms, and as the full imaging field of view is often used, the nonlinearity is pronounced. The purpose of this work is to show the system can produce clinically useful images after an on-site gradient nonlinearity calibration and correction, and show that acoustic noise levels fall within non-significant risk (NSR) limits for standard clinical pulse sequences. Methods: The head-only gradient system was inserted into a standard 3T wide-bore scanner without acoustic damping. The ACR phantom was scanned in an 8-channel receive-only head coil and the standard American College of Radiology (ACR) MRI quality control (QC) test was performed. Acoustic noise levels were measured for several standard pulse sequences. Results: Images acquired with the head-only gradient system passed all ACR MR image quality tests; Both even and odd-order gradient distortion correction terms were required for the asymmetric gradients to pass. Acoustic noise measurements were within FDA NSR guidelines of 99 dBA (with assumed 20 dBA hearing protection) A-weighted and 140 dB for peak for all but one sequence. Note the gradient system was installed without any shroud or acoustic batting. We expect final system integration to greatly reduce noise experienced by the patient. Conclusion: A high-performance head-only asymmetric gradient system operating at 80 mT/m and 500 T/m/s conforms to FDA acoustic noise limits in all but one case, and passes all the ACR MR image quality control tests. This work was supported in part by the NIH grant 5R01EB010065.

  1. Enlarging the angle of view in Michelson-interferometer-based shearography by embedding a 4f system

    Science.gov (United States)

    Wu, Sijin; He, Xiaoyuan; Yang, Lianxiang

    2011-07-01

    Digital shearography based on Michelson interferometers suffers from the disadvantage of a small angle of view due to the structure. We demonstrate a novel digital shearography system with a large angle of view. In the optical arrangement, the imaging lens is in front of the Michelson interferometer rather than behind it as in traditional digital shearography. Thus, the angle of view is no longer limited by the Michelson interferometer. The images transmitting between the separate lens and camera are accomplished by a 4f system in the new style of shearography. The influences of the 4f system on shearography are also discussed.

  2. Heterometallic 3d-4f single molecule magnets

    OpenAIRE

    Rosado Piquer, Lidia; Sañudo Zotes, Eva Carolina

    2015-01-01

    The promising potential applications, such as information processing and storage or molecular spintronics, of single-molecule magnets (SMMs) have spurred on the research of new, better SMMs. In this context, lanthanide ions have been seen as ideal candidates for new heterometallic transition metal-lanthanide SMMs. This perspective reviews 3d-4f SMMs up to 2014 and highlights the most significant advances and challenges of the field.

  3. Acoustic Imaging of Microstructure and Evaluation of the Adhesive's Physical, Mechanical and Chemical Properties Changes at Different Cure States

    Science.gov (United States)

    Severina, I. A.; Fabre, A. J.; Maeva, E. Yu.

    Epoxy thermoset adhesives transform during cure from liquid state into the highly cross-linked solid. Cure state of the material depends on condition of the reaction (temperature, pressure, time etc.) and resin/hardener ratio. It is known that the cure degree of the adhesive correlates with adhesion strength, which is critical for structural adhesives used in automotive, aerospace and marine industries. In this work, characterization of cure process of the adhesive with acoustic methods is presented. Evolution of the acoustic and elastic properties (attenuation, sound velocity, density, elastic moduli) during cure reaction was monitored in relation to the substantial physical and chemical changes of the material. These macro parameters of the adhesive were compared with the material's microstructure obtained by high-resolution acoustic microscopy technique in frequencies range of 50-400 MHz. Development of the microstructure of the adhesive as it cures at different conditions has been investigated. Appearance and development of the granular structure on the adhesive interface during cure reaction has been demonstrated. Acoustic images were analyzed by mathematical method to quantitatively characterize distribution of the adhesive's components. Statistical analysis of such images provides an accurate quantitative measure of the degree of cure of such samples. Research results presented in this paper can be useful as a basis for non-destructive evaluation of the adhesive materials

  4. Efficient modeling of flat and homogeneous acoustic treatments for vibroacoustic finite element analysis. Finite size correction by image sources

    Science.gov (United States)

    Alimonti, L.; Atalla, N.

    2017-02-01

    This work is concerned with the hybrid finite element-transfer matrix methodology recently proposed by the authors. The main assumption behind this hybrid method consists in neglecting the actual finite lateral extent of the acoustic treatment. Although a substantial increase of the computational efficiency can be achieved, the effect of the reflected field (i.e. finite size effects) may be sometimes important, preventing the hybrid model from giving quantitative meaningful results. For this reason, a correction to account for wave reflections at the lateral boundaries of the acoustic treatment is sought. It is shown in the present paper that the image source method can be successfully employed to retrieve such finite size effects. Indeed, such methodology is known to be effective when the response of the system is a smooth function of the frequency, like in the case of highly dissipative acoustic treatments. The main concern of this paper is to assess accuracy and feasibility of the image source method in the context of acoustic treatments modeling. Numerical examples show that the performance of the standard hybrid model can be substantially improved by the proposed correction without deteriorating excessively the computational efficiency.

  5. Correlation Time of Ocean Ambient Noise Intensity in San Diego Bay and Target Recognition in Acoustic Daylight Images

    Science.gov (United States)

    Wadsworth, Adam J.

    A method for passively detecting and imaging underwater targets using ambient noise as the sole source of illumination (named acoustic daylight) was successfully implemented in the form of the Acoustic Daylight Ocean Noise Imaging System (ADONIS). In a series of imaging experiments conducted in San Diego Bay, where the dominant source of high-frequency ambient noise is snapping shrimp, a large quantity of ambient noise intensity data was collected with the ADONIS (Epifanio, 1997). In a subset of the experimental data sets, fluctuations of time-averaged ambient noise intensity exhibited a diurnal pattern consistent with the increase in frequency of shrimp snapping near dawn and dusk. The same subset of experimental data is revisited here and the correlation time is estimated and analysed for sequences of ambient noise data several minutes in length, with the aim of detecting possible periodicities or other trends in the fluctuation of the shrimp-dominated ambient noise field. Using videos formed from sequences of acoustic daylight images along with other experimental information, candidate segments of static-configuration ADONIS raw ambient noise data were isolated. For each segment, the normalized intensity auto-correlation closely resembled the delta function, the auto-correlation of white noise. No intensity fluctuation patterns at timescales smaller than a few minutes were discernible, suggesting that the shrimp do not communicate, synchronise, or exhibit any periodicities in their snapping. Also presented here is a ADONIS-specific target recognition algorithm based on principal component analysis, along with basic experimental results using a database of acoustic daylight images.

  6. Differential diagnosis of idiopathic granulomatous mastitis and breast cancer using acoustic radiation force impulse imaging.

    Science.gov (United States)

    Teke, Memik; Teke, Fatma; Alan, Bircan; Türkoğlu, Ahmet; Hamidi, Cihad; Göya, Cemil; Hattapoğlu, Salih; Gumus, Metehan

    2017-01-01

    Differentiation of idiopathic granulomatous mastitis (IGM) from carcinoma with routine imaging methods, such as ultrasonography (US) and mammography, is difficult. Therefore, we evaluated the value of a newly developed noninvasive technique called acoustic radiation force impulse imaging in differentiating IGM versus malignant lesions in the breast. Four hundred and eighty-six patients, who were referred to us with a presumptive diagnosis of a mass, underwent Virtual Touch tissue imaging (VTI; Siemens) and Virtual Touch tissue quantification (VTQ; Siemens) after conventional gray-scale US. US-guided percutaneous needle biopsy was then performed on 276 lesions with clinically and radiologically suspicious features. Malignant lesions (n = 122) and IGM (n = 48) were included in the final study group. There was a statistically significant difference in shear wave velocity marginal and internal values between the IGM and malignant lesions. The median marginal velocity for IGM and malignant lesions was 3.19 m/s (minimum-maximum 2.49-5.82) and 5.05 m/s (minimum-maximum 2.09-8.46), respectively (p < 0.001). The median internal velocity for IGM and malignant lesions was 2.76 m/s (minimum-maximum 1.14-4.12) and 4.79 m/s (minimum-maximum 2.12-8.02), respectively (p < 0.001). The combination of VTI and VTQ as a complement to conventional US provides viscoelastic properties of tissues, and thus has the potential to increase the specificity of US.

  7. Quantitative Enhancement of Fatigue Crack Monitoring by Imaging Surface Acoustic Wave Reflection in a Space-Cycle Domain

    Science.gov (United States)

    Connolly, G. D.; Rokhlin, S. I.

    2011-06-01

    The surface wave acoustic method is applied to the in-situ monitoring of fatigue crack initiation and evolution on tension specimens. A small low-frequency periodic loading is also applied, resulting in a nonlinear modulation of reflected pulses. The acoustic wave reflections are collected for: each experimental cycle; a range of applied tension and modulation load levels; and a range of spatial propagation positions, and are presented in image form to aid pattern identification. Salient features of the image are then extracted and processed to evaluate the initiation time of the crack and its subsequent size evolution until sample failure. Additionally, a method for enhancing signal to noise ratio in Ti-6242 alloy samples is demonstrated.

  8. Acoustic radiation force impulse imaging for evaluation of the thyroid gland.

    Science.gov (United States)

    Calvete, Angela Cepero; Mestre, J Dios Berná; Gonzalez, Jose Manuel Rodriguez; Martinez, Elena Sáez; Sala, Begoña Torregrosa; Zambudio, Antonio Rios

    2014-06-01

    To study acoustic radiation force impulse (ARFI) imaging as a new quantitative and noninvasive tool for evaluating thyroid nodules and to compare ARFI imaging with other tools for studying thyroid nodules: sonography, real-time elastography, and fine-needle aspiration biopsy. We conducted a prospective study from June 2011 to June 2012, which analyzed 157 thyroid nodules (129 benign and 28 malignant) using the ARFI technique and a 9-MHz probe. Shear wave velocities (SWVs) were obtained while the patients held their breath to avoid respiratory movement artifacts. All nodules underwent conventional sonography and real-time elastography of the thyroid gland. All patients received either a cytologic examination using fine-needle aspiration biopsy or a histologic examination from thyroid surgery to verify the diagnosis (reference standard). The mean SWV ± SD on ARFI imaging in healthy, nodule-free thyroid glands was 2.04 ± 0.51 m/s (range, 0.76-3.63 m/s). The mean SWV in benign thyroid nodules was 1.70 ± 0.55 m/s (range, 0.50-2.80 m/s), and the mean SWV in malignant nodules was 3.39 ± 1.15 m/s (range, 1.50-6.08 m/s). When we used an SWV greater than 2.50 m/s for the diagnosis of malignant nodules and less than 2.50 m/s for the diagnosis of benign nodules, the sensitivity and specificity of ARFI imaging were 85.7% and 96.0%, respectively. We found that SWVs were substantially higher in malignant nodules than benign ones. Perhaps if ARFI imaging is used in conjunction with sonographic findings and patient demographics, it will be possible to find a combination of factors that would yield a negative predictive value high enough to distinguish benign from malignant nodules with confidence, which may lead to a decrease in the biopsy rate for benign nodules. © 2014 by the American Institute of Ultrasound in Medicine.

  9. Non-intrusive, high-resolution, real-time, two-dimensional imaging of multiphase materials using acoustic array sensors

    Science.gov (United States)

    Cassiède, M.; Shaw, J. M.

    2015-04-01

    Two parallel multi-element ultrasonic acoustic arrays combined with sets of focal laws for acoustic signal generation and a classical tomographic inversion algorithm are used to generate real-time two-dimensional micro seismic acoustic images of multiphase materials. Proof of concept and calibration measurements were performed for single phase and two phase liquids, uniform polyvinyl chloride (PVC) plates, and aluminum cylinders imbedded in PVC plates. Measurement artefacts, arising from the limited range of viewing angles, and the compromise between data acquisition rate and image quality are discussed. The angle range of scanning and the image resolution were varied, and the effects on the quality of the reproduction of the speed of sound profiles of model solids and liquids with known geometries and compositions were analysed in detail. The best image quality results were obtained for a scanning angle range of [-35°, 35°] at a step size of 2.5° post processed to generate images on a 40 μm square grid. The data acquisition time for high quality images with a 30 mm × 40 mm view field is 10 min. Representation of two-phase solids with large differences in speed of sound between phases and where one phase is dispersed in the form of macroscopic objects (greater than 1 mm in diameter) proved to be the most difficult to image accurately. Liquid-liquid and liquid-vapor phase boundaries, in micro porous solids by contrast, were more readily defined. Displacement of air by water and water by heptane in natural porous limestone provides illustrative kinetic examples. Measurement results with these realistic cases demonstrate the feasibility of the technique to monitor in real time and on the micrometer length scale local composition and flow of organic liquids in inorganic porous media, one of many envisioned engineering applications. Improvement of data acquisition rate is an area for future collaborative study.

  10. Breast Lesions Evaluated by Color-Coded Acoustic Radiation Force Impulse (ARFI) Imaging.

    Science.gov (United States)

    Zhou, JianQiao; Yang, ZhiFang; Zhan, WeiWei; Zhang, JingWen; Hu, Na; Dong, YiJie; Wang, YingYing

    2016-07-01

    The goal of our study was to investigate the value of color-coded Virtual Touch tissue imaging (VTI) using acoustic radiation force impulse (ARFI) technology in the characterization of breast lesions and to compare it with conventional ultrasound (US). Conventional US and color-coded VTI were performed in 196 solid breast lesions in 196 consecutive women (age range 17-91 y; mean 48.17 ± 14.46 y). A four-point scale VTI score was assigned for each lesion according to the color pattern both in the lesion and in the surrounding breast tissue. The mean VTI score was significantly higher for malignant lesions (3.80 ± 0.66, range 1-4) than for benign ones (2.02 ± 1.20, range 1-4) (p breast lesions. Copyright © 2016 World Federation for Ultrasound in Medicine & Biology. Published by Elsevier Inc. All rights reserved.

  11. Detecting crack profile in concrete using digital image correlation and acoustic emission

    Directory of Open Access Journals (Sweden)

    Loukili A.

    2010-06-01

    Full Text Available Failure process in concrete structures is usually accompanied by cracking of concrete. Understanding the cracking pattern is very important while studying the failure governing criteria of concrete. The cracking phenomenon in concrete structures is usually complex and involves many microscopic mechanisms caused by material heterogeneity. Since last many years, fracture or damage analysis by experimental examinations of the cement based composites has shown importance to evaluate the cracking and damage behavior of those heterogeneous materials with damage accumulation due to microcracks development ahead of the propagating crack tip; and energy dissipation resulted during the evolution of damage in the structure. The techniques used in those experiments may be the holographic interferometry, the dye penetration, the scanning electron microscopy, the acoustic emission etc. Those methods offer either the images of the material surface to observe micro-features of the concrete with qualitative analysis, or the black-white fringe patterns of the deformation on the specimen surface, from which it is difficult to observe profiles of the damaged materials.

  12. Optically and acoustically triggerable sub-micron phase-change contrast agents for enhanced photoacoustic and ultrasound imaging

    Directory of Open Access Journals (Sweden)

    Shengtao Lin

    2017-06-01

    Full Text Available We demonstrate a versatile phase-change sub-micron contrast agent providing three modes of contrast enhancement: 1 photoacoustic imaging contrast, 2 ultrasound contrast with optical activation, and 3 ultrasound contrast with acoustic activation. This agent, which we name ‘Cy-droplet’, has the following novel features. It comprises a highly volatile perfluorocarbon for easy versatile activation, and a near-infrared optically absorbing dye chosen to absorb light at a wavelength with good tissue penetration. It is manufactured via a ‘microbubble condensation’ method. The phase-transition of Cy-droplets can be optically triggered by pulsed-laser illumination, inducing photoacoustic signal and forming stable gas bubbles that are visible with echo-ultrasound in situ. Alternatively, Cy-droplets can be converted to microbubble contrast agents upon acoustic activation with clinical ultrasound. Potentially all modes offer extravascular contrast enhancement because of the sub-micron initial size. Such versatility of acoustic and optical ‘triggerability’ can potentially improve multi-modality imaging, molecularly targeted imaging and controlled drug release.

  13. Optically and acoustically triggerable sub-micron phase-change contrast agents for enhanced photoacoustic and ultrasound imaging.

    Science.gov (United States)

    Lin, Shengtao; Shah, Anant; Hernández-Gil, Javier; Stanziola, Antonio; Harriss, Bethany I; Matsunaga, Terry O; Long, Nicholas; Bamber, Jeffrey; Tang, Meng-Xing

    2017-06-01

    We demonstrate a versatile phase-change sub-micron contrast agent providing three modes of contrast enhancement: 1) photoacoustic imaging contrast, 2) ultrasound contrast with optical activation, and 3) ultrasound contrast with acoustic activation. This agent, which we name 'Cy-droplet', has the following novel features. It comprises a highly volatile perfluorocarbon for easy versatile activation, and a near-infrared optically absorbing dye chosen to absorb light at a wavelength with good tissue penetration. It is manufactured via a 'microbubble condensation' method. The phase-transition of Cy-droplets can be optically triggered by pulsed-laser illumination, inducing photoacoustic signal and forming stable gas bubbles that are visible with echo-ultrasound in situ . Alternatively, Cy-droplets can be converted to microbubble contrast agents upon acoustic activation with clinical ultrasound. Potentially all modes offer extravascular contrast enhancement because of the sub-micron initial size. Such versatility of acoustic and optical 'triggerability' can potentially improve multi-modality imaging, molecularly targeted imaging and controlled drug release.

  14. Toward Molecular 4f Single-Ion Magnet Qubits.

    Science.gov (United States)

    Pedersen, Kasper S; Ariciu, Ana-Maria; McAdams, Simon; Weihe, Høgni; Bendix, Jesper; Tuna, Floriana; Piligkos, Stergios

    2016-05-11

    Quantum coherence is detected in the 4f single-ion magnet (SIM) Yb(trensal), by isotope selective pulsed EPR spectroscopy on an oriented single crystal. At X-band, the spin-lattice relaxation (T1) and phase memory (Tm) times are found to be independent of the nuclei bearing, or not, a nuclear spin. The observation of Rabi oscillations of the spin echo demonstrates the possibility to coherently manipulate the system for more than 70 rotations. This renders Yb(trensal), a sublimable and chemically modifiable SIM, an excellent candidate for quantum information processing.

  15. Selective magnetic resonance imaging of magnetic nanoparticles by acoustically induced rotary saturation

    National Research Council Canada - National Science Library

    Zhu, Bo; Witzel, Thomas; Jiang, Shan; Huang, Susie Y; Rosen, Bruce R; Wald, Lawrence L

    2016-01-01

    The goal of this study was to introduce a new method to selectively detect iron oxide contrast agents using an acoustic wave to perturb the spin-locked water signal in the vicinity of the magnetic particles...

  16. Seeing Sound - Image Analysis of the Lift-off Acoustic Field Project

    Data.gov (United States)

    National Aeronautics and Space Administration — A launch vehicle and its launch facilities are subjected to intense acoustic loads generated by the vehicle's propulsion system. The vehicle, its payload, and...

  17. Using auditory classification images for the identification of fine acoustic cues used in speech perception.

    Directory of Open Access Journals (Sweden)

    Léo eVarnet

    2013-12-01

    Full Text Available An essential step in understanding the processes underlying the general mechanism of perceptual categorization is to identify which portions of a physical stimulation modulate the behavior of our perceptual system. More specifically, in the context of speech comprehension, it is still a major open challenge to understand which information is used to categorize a speech stimulus as one phoneme or another, the auditory primitives relevant for the categorical perception of speech being still unknown. Here we propose to adapt technique relying on a Generalized Linear Model with smoothness priors technique, already used in the visual domain for estimation of so-called classification images, to auditory experiments. This statistical model offers a rigorous framework for dealing with non-Gaussian noise, as it is often the case in the auditory modality, and limits the amount of noise in the estimated template by enforcing smoother solution. By applying this technique to a specific two-alternative forced choice experiment between stimuli ‘aba’ and ‘ada’ in noise with an adaptive SNR, we confirm that the second formantic transition is a key for classifying phonemes into /b/ or /d/ in noise, and that its estimation by the auditory system is a relative measurement across spectral bands and in relation to the perceived height of the second formant in the preceding syllable. Through this example, we show how the GLM with smoothness priors approach can be applied to the identification of fine functional acoustic cues in speech perception. Finally we discuss some assumptions of the model in the specific case of speech perception.

  18. The screening of 4f moments and delocalization in the compressed light rare earths

    OpenAIRE

    McMahan, A.K.; Scalettar, R. T.; Jarrell, M.

    2009-01-01

    Spin and charge susceptibilities and the 4f^n, 4f^{n-1}, and 4f^{n+1} configuration weights are calculated for compressed Ce (n=1), Pr (n=2), and Nd (n=3) metals using dynamical mean field theory combined with the local-density approximation. At ambient and larger volumes these trivalent rare earths are pinned at sharp 4f^n configurations, their 4f moments assume atomic-limiting values, are unscreened, and the 4f charge fluctuations are small indicating little f state density near the Fermi l...

  19. Apparatus for real-time acoustic imaging of Rayleigh-Bénard convection

    Energy Technology Data Exchange (ETDEWEB)

    Kuehn, Kerry, K.

    2008-10-28

    We have successfully designed, built and tested an experimental apparatus which is capable of providing the first real-time ultrasound images of Rayleigh-B\\'{e}nard convection in optically opaque fluids confined to large aspect ratio experimental cells. The apparatus employs a modified version of a commercially available ultrasound camera to capture images (30 frames per second) of flow patterns in a fluid undergoing Rayleigh Bénard convection. The apparatus was validated by observing convection rolls in 5cSt polydimethylsiloxane (PDMS) polymer fluid. Our first objective, after having built the apparatus, was to use it to study the sequence of transitions from diffusive to time--dependent heat transport in liquid mercury. The aim was to provide important information on pattern formation in the largely unexplored regime of very low Prandtl number fluids. Based on the theoretical stability diagram for liquid mercury, we anticipated that straight rolls should be stable over a range of Rayleigh numbers, between 1708 and approximately 1900. Though some of our power spectral densities were suggestive of the existence of weak convection, we have been unable to unambiguously visualize stable convection rolls above the theoretical onset of convection in liquid mercury. Currently, we are seeking ways to increase the sensitivity of our apparatus, such as (i) improving the acoustic impedance matching between our materials in the ultrasound path and (ii) reducing the noise level in our acoustic images due to turbulence and cavitation in the cooling fluids circulating above and below our experimental cell. If we are able to convincingly improve the sensitivity of our apparatus, and we still do not observe stable convection rolls in liquid mercury, then it may be the case that the theoretical stability diagram requires revision. In that case, either (i) straight rolls are not stable in a large aspect ratio cell at the Prandtl numbers associated with liquid mercury, or (ii

  20. A single-sided homogeneous Green's function representation for holographic imaging, inverse scattering, time-reversal acoustics and interferometric Green's function retrieval

    NARCIS (Netherlands)

    Wapenaar, C.P.A.; Thorbecke, J.W.; van der Neut, J.R.

    2016-01-01

    Green's theorem plays a fundamental role in a diverse range of wavefield imaging applications, such as holographic imaging, inverse scattering, time-reversal acoustics and interferometric Green's function retrieval. In many of those applications, the homogeneous Green's function (i.e. the Green's

  1. ACOUSTICAL IMAGING AND MECHANICAL PROPERTIES OF SOFT ROCK AND MARINE SEDIMENTS

    Energy Technology Data Exchange (ETDEWEB)

    Thurman E. Scott, Jr., Ph.D.; Younane Abousleiman, Ph.D.; Musharraf Zaman, Ph.D., P.E.

    2001-07-01

    Mechanically weak formations, such as chalks, high porosity sandstones, and marine sediments, pose significant problems for oil and gas operators. Problems such as compaction, subsidence, and loss of permeability can affect reservoir production operations. For example, the unexpected subsidence of the Ekofisk chalk in the North Sea required over one billion dollars to re-engineer production facilities to account for losses created during that compaction (Sulak 1991). Another problem in weak formations is that of shallow water flows (SWF). Deep water drilling operations sometimes encounter cases where the marine sediments, at shallow depths just below the seafloor, begin to uncontrollably flow up and around the drill pipe. SWF problems created a loss of $150 million for the Ursa development project in the U.S. Gulf Coast SWF (Furlow 1998a,b; 1999a,b). The goal of this project is to provide a database on both the rock mechanical properties and the geophysical properties of weak rocks and sediments. These could be used by oil and gas companies to detect, evaluate, and alleviate potential production and drilling problems. The results will be useful in, for example, pre-drill detection of events such as SWF's by allowing a correlation of seismic data (such as hazard surveys) to rock mechanical properties. The data sets could also be useful for 4-D monitoring of the compaction and subsidence of an existing reservoir and imaging the zones of damage. During the second quarter of the project the research team has: (1) completed acoustic sensor construction, (2) conducted reconnaissance tests to map the deformational behaviors of the various rocks, (3) developed a sample assembly for the measurement of dynamic elastic and poroelastic parameters during triaxial testing, and (4) conducted a detailed review of the scientific literature and compiled a bibliography of that review. During the first quarter of the project the research team acquired several rock types for

  2. Integration of acoustic radiation force and optical imaging for blood plasma clot stiffness measurement.

    Directory of Open Access Journals (Sweden)

    Caroline W Wang

    Full Text Available Despite the life-preserving function blood clotting serves in the body, inadequate or excessive blood clot stiffness has been associated with life-threatening diseases such as stroke, hemorrhage, and heart attack. The relationship between blood clot stiffness and vascular diseases underscores the importance of quantifying the magnitude and kinetics of blood's transformation from a fluid to a viscoelastic solid. To measure blood plasma clot stiffness, we have developed a method that uses ultrasound acoustic radiation force (ARF to induce micron-scaled displacements (1-500 μm on microbeads suspended in blood plasma. The displacements were detected by optical microscopy and took place within a micro-liter sized clot region formed within a larger volume (2 mL sample to minimize container surface effects. Modulation of the ultrasound generated acoustic radiation force allowed stiffness measurements to be made in blood plasma from before its gel point to the stage where it was a fully developed viscoelastic solid. A 0.5 wt % agarose hydrogel was 9.8-fold stiffer than the plasma (platelet-rich clot at 1 h post-kaolin stimulus. The acoustic radiation force microbead method was sensitive to the presence of platelets and strength of coagulation stimulus. Platelet depletion reduced clot stiffness 6.9 fold relative to platelet rich plasma. The sensitivity of acoustic radiation force based stiffness assessment may allow for studying platelet regulation of both incipient and mature clot mechanical properties.

  3. Acoustic profiles and images of the Palos Verdes margin: implications concerning deposition from the White's Point outfall

    Science.gov (United States)

    Hampton, Monty A.; Karl, Herman A.; Murray, Christopher J.

    2002-05-01

    Subbottom profiles and sidescan-sonar images collected on and around the Palos Verdes Shelf show a surficial deposit interpreted to contain effluent from the White's Point diffusers, as well as showing several geologic features that affect the deposit's distribution. The effluent-affected deposit is visible in high-resolution subbottom profiles on the shelf and the adjacent San Pedro basin slope to water depths of 170 m. It has a maximum thickness of 75 cm and was mapped acoustically over an area of 10.8 km 2, which encompasses a volume of about 3.2 million m 3. The deposit's basal reflector is acoustically distinct over most of the mapped area, implying that the deposit has not been extensively mixed across its base, perhaps being relatively free of reworking since its initial deposition. Nearshore, the basal reflector is weak and fades away toward land, which could result from syndepositional intermixing of coarse native sediment (particularly from the Portuguese Bend landslide) with effluent in the high-energy nearshore zone, or postdepositionally by physical (wave) or biological mixing across the interface. The geometry of the deposit implies that effluent is dispersed primarily in a northwesterly and seaward direction from the diffusers. Dispersal across the shelf break is in some places strongly affected by topography, particularly by submarine canyons. The deposit overlies stratified and unstratified Quaternary sediment, up to 30 m thick, that in turn overlies the irregular erosional surface of deformed Miocene bedrock that crops out in places on the shelf and upper basin slope. The effluent-affected deposit rests on potentially unstable landslide deposits on the San Pedro basin slope. The acoustic profiles and side-scan images show evidence for active and inactive vents, probably of hot water and gas, some of which are within the boundary of the effluent-affected sediment deposit and could disrupt it if seepage occurs.

  4. Evaluating the Benefit of Elevated Acoustic Output in Harmonic Motion Estimation in Ultrasonic Shear Wave Elasticity Imaging.

    Science.gov (United States)

    Deng, Yufeng; Palmeri, Mark L; Rouze, Ned C; Haystead, Clare M; Nightingale, Kathryn R

    2018-02-01

    Harmonic imaging techniques have been applied in ultrasonic elasticity imaging to obtain higher-quality tissue motion tracking data. However, harmonic tracking can be signal-to-noise ratio and penetration depth limited during clinical imaging, resulting in decreased yield of successful shear wave speed measurements. A logical approach is to increase the source pressure, but the in situ pressures used in diagnostic ultrasound have been subject to a de facto upper limit based on the Food and Drug Administration guideline for the mechanical index (MI harmonic motion tracking for hepatic shear wave elasticity imaging. The studies indicate that high-MI harmonic tracking increased shear wave speed estimation yield by 27% at a focal depth of 5 cm, with larger yield increase in more difficult-to-image patients. High-MI tracking improved harmonic tracking data quality by increasing the signal-to-noise ratio and decreasing jitter in the tissue motion data. We conclude that there is clinical benefit to use of elevated acoustic output in shear wave tracking, particularly in difficult-to-image patients. Copyright © 2018 World Federation for Ultrasound in Medicine and Biology. Published by Elsevier Inc. All rights reserved.

  5. Investigation of energy shift of 4f3 and 4f5d levels in Nd-doped YLF and LLF crystals

    Directory of Open Access Journals (Sweden)

    André Felipe Henriques Librantz

    2006-01-01

    Full Text Available We observed ultraviolet (UV luminescence from 4f25d and 4f3 configuration in Nd-doped YLiF4 (YLF and LuLiF4 (LLF crystals induced by multiphotonic excitation of the three photons (532 nanometers [nm]. The LLF lattice is more compact than the YLF crystal and favours an absorption and emission shift of the main peaks due to crystal field strength. The red and blue shifts of the emission bands towards to lower (and higher energy are different for the transitions from 4f3 and 4f25d levels. The 4f3 transitions have smaller shift (~5 times smaller than the shift of the 4f25d due to 5s25p6 closed-shell shielding effect. On the other hand the 4f25d transitions are more susceptible to lattice change. The effect of the crystalline field was compared for both lattice. The result shows that these emission bands from 4f25d configuration always shift to lower energy when substituting the Y3+ by Lu3+ (i.e., the last one has the ionic radius 5% smaller than Y3+.

  6. The progressive role of acoustic cavitation for non-invasive therapies, contrast imaging and blood-tumor permeability enhancement.

    Science.gov (United States)

    Aw, Moom Sinn; Paniwnyk, Larysa; Losic, Dusan

    2016-10-01

    Drug delivery pertaining to acoustic cavitation generated from ultrasonic (US) irradiation is advantageous for devising smarter and more advanced therapeutics. The aim is to showcase microbubbles as drug carriers and robust theranostic for non-invasive therapies across diverse biomedical disciplines, highlighting recent technologies in this field for overcoming the blood-brain barrier (BBB) to treat cancers and neurological disorders. This article reviews work on the optimized tuning of ultrasonic parameters, sonoporation, transdermal and responsive drug delivery, acoustic cavitation in vasculature and oncology, contrast imaging for real-time magnification of cell-microbubble dynamics and biomolecular targeting. Scholarly literature was sought through database search on key terminology, latest topics, reputable experts and established journals over the last five years. Cavitation offers immense promise in overcoming current diffusion and convection limitations for treating skull/brain/vascular/tissue injuries and ablating tumors to minimize chronic/acute effects. Since stable cavitation facilitates the restoration of US-opened BBB and the modulation of drug concentration, US equipment with programmable imaging modality and sensitivity are envisaged to create safer miniaturized devices for personalized care. Due to differing biomedical protocols with regard to specific medical conditions, quantitative and qualitative controls are mandatory before translation to real-life clinical applications can be accomplished.

  7. Simultaneous observation of cavitation bubbles generated in biological tissue by high-speed optical and acoustic imaging methods

    Science.gov (United States)

    Suzuki, Kai; Iwasaki, Ryosuke; Takagi, Ryo; Yoshizawa, Shin; Umemura, Shin-ichiro

    2017-07-01

    Acoustic cavitation bubbles are useful for enhancing the heating effect in high-intensity focused ultrasound (HIFU) treatment. Many studies were conducted to investigate the behavior of such bubbles in tissue-mimicking materials, such as a transparent gel phantom; however, the detailed behavior in tissue was still unclear owing to the difficulty in optical observation. In this study, a new biological phantom was developed to observe cavitation bubbles generated in an optically shallow area of tissue. Two imaging methods, high-speed photography using light scattering and high-speed ultrasonic imaging, were used for detecting the behavior of the bubbles simultaneously. The results agreed well with each other for the area of bubble formation and the temporal change in the region of bubbles, suggesting that both methods are useful for visualizing the bubbles.

  8. Experimental Study of High-Range-Resolution Medical Acoustic Imaging for Multiple Target Detection by Frequency Domain Interferometry

    Science.gov (United States)

    Kimura, Tomoki; Taki, Hirofumi; Sakamoto, Takuya; Sato, Toru

    2009-07-01

    We employed frequency domain interferometry (FDI) for use as a medical acoustic imager to detect multiple targets with high range resolution. The phase of each frequency component of an echo varies with the frequency, and target intervals can be estimated from the phase variance. This processing technique is generally used in radar imaging. When the interference within a range gate is coherent, the cross correlation between the desired signal and the coherent interference signal is nonzero. The Capon method works under the guiding principle that output power minimization cancels the desired signal with a coherent interference signal. Therefore, we utilize frequency averaging to suppress the correlation of the coherent interference. The results of computational simulations using a pseudoecho signal show that the Capon method with adaptive frequency averaging (AFA) provides a higher range resolution than a conventional method. These techniques were experimentally investigated and we confirmed the effectiveness of the proposed method of processing by FDI.

  9. Applications of Lorentz force in medical acoustics: Lorentz force hydrophone, Lorentz Force Electrical Impedance Tomography, Imaging of shear waves induced by Lorentz force

    CERN Document Server

    Grasland-Mongrain, Pol

    2014-01-01

    The ability of the Lorentz force to link a mechanical displacement to an electrical current presents a strong interest for medical acoustics, and three applications were studied in this thesis. In the first part of this work, a hydrophone was developed for mapping the particle velocity of an acoustic field. This hydrophone was constructed using a thin copper wire and an external magnetic field. A model was elaborated to determine the relationship between the acoustic pressure and the measured electrical current, which is induced by Lorentz force when the wire vibrates in the acoustic field of an ultrasound transducer. The built prototype was characterized and its spatial resolution, frequency response, sensitivity, robustness and directivity response were investigated. An imaging method called Lorentz Force Electrical Impedance Tomography was also studied. In this method, a biological tissue is vibrated by ultrasound in a magnetic field, which induces an electrical current by Lorentz force. The electrical imp...

  10. Evidence from acoustic imaging for submarine volcanic activity in 2012 off the west coast of El Hierro (Canary Islands, Spain)

    Science.gov (United States)

    Pérez, Nemesio M.; Somoza, Luis; Hernández, Pedro A.; de Vallejo, Luis González; León, Ricardo; Sagiya, Takeshi; Biain, Ander; González, Francisco J.; Medialdea, Teresa; Barrancos, José; Ibáñez, Jesús; Sumino, Hirochika; Nogami, Kenji; Romero, Carmen

    2014-12-01

    We report precursory geophysical, geodetic, and geochemical signatures of a new submarine volcanic activity observed off the western coast of El Hierro, Canary Islands. Submarine manifestation of this activity has been revealed through acoustic imaging of submarine plumes detected on the 20-kHz chirp parasound subbottom profiler (TOPAS PS18) mounted aboard the Spanish RV Hespérides on June 28, 2012. Five distinct "filament-shaped" acoustic plumes emanating from the flanks of mounds have been recognized at water depth between 64 and 88 m on a submarine platform located NW El Hierro. These plumes were well imaged on TOPAS profiles as "flares" of high acoustic contrast of impedance within the water column. Moreover, visible plumes composed of white rafts floating on the sea surface and sourcing from the location of the submarine plumes were reported by aerial photographs on July 3, 2012, 5 days after acoustic plumes were recorded. In addition, several geophysical and geochemical data support the fact that these submarine vents were preceded by several precursory signatures: (i) a sharp increase of the seismic energy release and the number of daily earthquakes of magnitude ≥2.5 on June 25, 2012, (ii) significant vertical and horizontal displacements observed at the Canary Islands GPS network (Nagoya University-ITER-GRAFCAN) with uplifts up to 3 cm from June 25 to 26, 2012, (iii) an anomalous increase of the soil gas radon activity, from the end of April until the beginning of June reaching peak values of 2.7 kBq/m3 on June 3, 2012, and (iv) observed positive peak in the air-corrected value of 3He/4He ratio monitored in ground waters (8.5 atmospheric 3He/4He ratio ( R A)) at the northwestern El Hierro on June 16, 2012. Combining these submarine and subaerial information, we suggest these plumes are the consequence of submarine vents exhaling volcanic gas mixed with fine ash as consequence of an event of rapid rise of volatile-rich magma beneath the NW submarine ridge

  11. Inspection of copper canisters for spent nuclear fuel by means of ultrasound. Nonlinear acoustics, synthetic aperture imaging

    Energy Technology Data Exchange (ETDEWEB)

    Lingvall, Fredrik; Ping Wu; Stepinski, Tadeusz [Uppsala Univ., (Sweden). Dept. of Materials Science

    2003-03-01

    This report contains results concerning inspection of copper canisters for spent nuclear fuel by means of ultrasound obtained at Signals and Systems, Uppsala University in year 2001/2002. The first chapter presents results of an investigation of a new method for synthetic aperture imaging. The new method presented here takes the form of a 2D filter based on minimum mean squared error (MMSE) criteria. The filter, which varies with the target position in two dimensions includes information about spatial impulse response (SIR) of the imaging system. Spatial resolution of the MMSE method is investigated and compared experimentally to that of the classical SAFT and phased array imaging. It is shown that the resolution of the MMSE algorithm, evaluated for imaging immersed copper specimen is superior to that observed for the two above-mentioned methods. Extended experimental and theoretical research concerning the potential of nonlinear waves and material harmonic imaging is presented in the second chapter. An experimental work is presented that was conducted using the RITEC RAM-5000 ultrasonic system capable of providing a high power tone-burst output. A new method for simulation of nonlinear acoustic waves that is a combination of the angular spectrum approach and the Burger's equation is also presented. This method was used for simulating nonlinear elastic waves radiated by the annular transducer that was used in the experiments.

  12. Structural relationships among LiNaMg[PO4]F and Na2M[PO4]F (M = Mn-Ni, and Mg), and the magnetic structure of LiNaNi[PO4]F.

    Science.gov (United States)

    Ben Yahia, Hamdi; Shikano, Masahiro; Kobayashi, Hironori; Avdeev, Maxim; Liu, Samuel; Ling, Chris D

    2014-02-07

    The new compound LiNaMg[PO4]F has been synthesized by a wet chemical reaction route. Its crystal structure was determined from single-crystal X-ray diffraction data. LiNaMg[PO4]F crystallizes with the monoclinic pseudomerohedrally twinned LiNaNi[PO4]F structure, space group P2(1)/c, a = 6.772(4), b = 11.154(6), c = 5.021(3) Å, β = 90.00(1)° and Z = 4. The structure contains [MgO3F]n chains made up of zigzag edge-sharing MgO4F2 octahedra. These chains are interlinked by PO4 tetrahedra forming 2D-Mg[PO4]F layers. The alkali metal atoms are well ordered in between these layers over two atomic positions. The use of group-subgroup transformation schemes in the Bärnighausen formalism enabled us to determine precise phase transition mechanisms from LiNaNi[PO4]F- to Na2M[PO4]F-type structures (M = Mn-Ni, and Mg) (see video clip 1 and 2). The crystal and magnetic structure and properties of the parent LiNaNi[PO4]F phase were also studied by magnetometry and neutron powder diffraction. Despite the rather long interlayer distance, d(min)(Ni(+2)-Ni(+2)) ~ 6.8 Å, the material develops a long-range magnetic order below 5 K. The magnetic structure can be viewed as antiferromagnetically coupled ferromagnetic layers with moments parallel to the b-axis.

  13. Effects of tissue mechanical and acoustic anisotropies on the performance of a cross-correlation-based ultrasound strain imaging method

    Science.gov (United States)

    Li, He; Lee, Wei-Ning

    2017-02-01

    The anisotropic mechanical properties (mechanical anisotropy) and view-dependent ultrasonic backscattering (acoustic anisotropy) of striated muscle due to the underlying myofiber arrangement have been well documented, but whether they impact on ultrasound strain imaging (USI) techniques remains unclear. The aim of this study was therefore to investigate the performance of a cross-correlation-based two-dimensional (2D) USI method in anisotropic media under controlled quasi-static compression in silico and in vitro. First, synthetic pre- and post-deformed 2D radiofrequency images of anisotropic phantoms were simulated in two scenarios to examine the individual effect of the mechanical and acoustic anisotropies on strain estimation. In the first scenario, the phantom was defined to be transversely isotropic with the scatterer amplitudes following a zero-mean Gaussian distribution, while in the second scenario, the phantom was defined to be mechanically isotropic with Gaussian distributed scatterer amplitudes correlated along the principal directions of pre-defined fibers. These two anisotropies were then jointly incorporated into the ultrasound image simulation model with additional depth-dependent attenuation. Three imaging planes—the fiber plane with the fiber direction perpendicular to the ultrasound beam (TISperp_fb), the fiber plane with the fiber direction parallel to the beam (TISpara), and the transverse fiber plane (TISperp_cfb)—were studied. The absolute relative error (ARE) of the lateral strain estimates in TISperp_fb (20.99  ±  15.65%) was much higher than that in TISperp_cfb (4.14  ±  3.17%). The ARE in TISpara was unavailable owing to the large spatial extent of false peaks. The effect of tissue anisotropy on the performance of the 2D USI was further confirmed in an in vitro porcine skeletal muscle phantom. The best in-plane strain quality was again shown in TISperp_cfb (elastographic signal-to-noise ratio, or SNRe:  >25 d

  14. VHMPID RICH prototype using pressurized C4F8O radiator gas and VUV photon detector

    Science.gov (United States)

    Acconcia, T. V.; Agócs, A. G.; Barile, F.; Barnaföldi, G. G.; Bellwied, R.; Bencédi, G.; Bencze, G.; Berényi, D.; Boldizsár, L.; Chattopadhyay, S.; Chinellato, D. D.; Cindolo, F.; Cossyleon, K.; Das, D.; Das, K.; Das-Bose, L.; Dash, A. K.; D`Ambrosio, S.; De Cataldo, G.; De Pasquale, S.; Di Bari, D.; Di Mauro, A.; Futó, E.; Garcia-Solis, E.; Hamar, G.; Harton, A.; Iannone, G.; Jimenez, R. T.; Kim, D. W.; Kim, J. S.; Knospe, A.; Kovács, L.; Lévai, P.; Markert, C.; Martinengo, P.; Molnár, L.; Nappi, E.; Oláh, L.; Paić, G.; Pastore, C.; Patimo, G.; Patino, M. E.; Peskov, V.; Pinsky, L.; Piuz, F.; Pochybová, S.; Sgura, I.; Sinha, T.; Song, J.; Takahashi, J.; Timmins, A.; Van Beelen, J. B.; Varga, D.; Volpe, G.; Weber, M.; Xaplanteris, L.; Yi, J.; Yoo, I.-K.

    2014-12-01

    A small-size prototype of a new Ring Imaging Cherenkov (RICH) detector using for the first time pressurized C4F8O radiator gas and a photon detector consisting of MWPC equipped with a CsI photocathode has been built and tested at the PS accelerator at CERN. It contained all the functional elements of the detector proposed as Very High Momentum Particle Identification (VHMPID) upgrade for the ALICE experiment at LHC to provide charged hadron track-by-track identification in the momentum range starting from 5 potentially up to 25 GeV/c. In the paper the equipment and its elements are described and some characteristic test results are shown.

  15. Mainstream Smoke Chemistry and in Vitro and In Vivo Toxicity of the Reference Cigarettes 3R4F and 2R4F

    Directory of Open Access Journals (Sweden)

    Roemer E

    2014-12-01

    Full Text Available A new reference cigarette, the 3R4F, has been developed to replace the depleting supply of the 2R4F cigarette. The present study was designed to compare mainstream smoke chemistry and toxicity of the two reference cigarettes under the International Organization for Standardization (ISO machine smoking conditions, and to further compare mainstream smoke chemistry and toxicological activity of the 3R4F cigarette by two different smoking regimens, i.e., the machine smoking conditions specified by ISO and the Health Canada intensive (HCI smoking conditions.

  16. Maximum Likelihood Deconvolution of Beamformed Images with Signal-Dependent Speckle Fluctuations from Gaussian Random Fields: With Application to Ocean Acoustic Waveguide Remote Sensing (OAWRS

    Directory of Open Access Journals (Sweden)

    Ankita D. Jain

    2016-08-01

    Full Text Available Wide area acoustic remote sensing often involves the use of coherent receiver arrays to determine the spatial distribution of sources and scatterers at any instant. The resulting acoustic intensity images are typically corrupted by signal-dependent noise from Gaussian random field fluctuations arising from the central limit theorem and have a spatial resolution that depends on the incident direction, sensing array aperture and wavelength. Here, we use the maximum likelihood method to deconvolve the intensity distribution measured on a coherent line array assuming a discrete angular distribution of incident plane waves. Instantaneous wide area population density images of fish aggregations measured with Ocean Acoustic Waveguide Remote Sensing (OAWRS are deconvolved to illustrate the effectiveness of this approach in improving angular resolution over conventional planewave beamforming.

  17. Detecting the activation of a self-healing mechanism in concrete by acoustic emission and digital image correlation.

    Science.gov (United States)

    Tsangouri, E; Aggelis, D G; Van Tittelboom, K; De Belie, N; Van Hemelrijck, D

    2013-01-01

    Autonomous crack healing in concrete is obtained when encapsulated healing agent is embedded into the material. Cracking damage in concrete elements ruptures the capsules and activates the healing process by healing agent release. Previously, the strength and stiffness recovery as well as the sealing efficiency after autonomous crack repair was well established. However, the mechanisms that trigger capsule breakage remain unknown. In parallel, the conditions under which the crack interacts with embedded capsules stay black-box. In this research, an experimental approach implementing an advanced optical and acoustic method sets up scopes to monitor and justify the crack formation and capsule breakage of concrete samples tested under three-point bending. Digital Image Correlation was used to visualize the crack opening. The optical information was the basis for an extensive and analytical study of the damage by Acoustic Emission analysis. The influence of embedding capsules on the concrete fracture process, the location of capsule damage, and the differentiation between emissions due to capsule rupture and crack formation are presented in this research. A profound observation of the capsules performance provides a clear view of the healing activation process.

  18. Detecting the Activation of a Self-Healing Mechanism in Concrete by Acoustic Emission and Digital Image Correlation

    Directory of Open Access Journals (Sweden)

    E. Tsangouri

    2013-01-01

    Full Text Available Autonomous crack healing in concrete is obtained when encapsulated healing agent is embedded into the material. Cracking damage in concrete elements ruptures the capsules and activates the healing process by healing agent release. Previously, the strength and stiffness recovery as well as the sealing efficiency after autonomous crack repair was well established. However, the mechanisms that trigger capsule breakage remain unknown. In parallel, the conditions under which the crack interacts with embedded capsules stay black-box. In this research, an experimental approach implementing an advanced optical and acoustic method sets up scopes to monitor and justify the crack formation and capsule breakage of concrete samples tested under three-point bending. Digital Image Correlation was used to visualize the crack opening. The optical information was the basis for an extensive and analytical study of the damage by Acoustic Emission analysis. The influence of embedding capsules on the concrete fracture process, the location of capsule damage, and the differentiation between emissions due to capsule rupture and crack formation are presented in this research. A profound observation of the capsules performance provides a clear view of the healing activation process.

  19. 4f?4f absorption spectra and hypersensitivity in nine-coordinate Ho(III) and Er(III) complexes in different environments

    Science.gov (United States)

    Khan, Azad A.; Hussain, H. A.; Iftikhar, K.

    2004-07-01

    The effect of change in the environment upon 4f-4f absorption spectra of nine-coordinate Ho(III) and Er(III) complexes with thiocyanate and 2,2'-bipyridyl in methanol, DMSO, DMF and pyridine have been investigated. The oscillator strength for hypersensitive and non-hypersensitive transitions have been calculated and variation in the intensity and band shape with respect to solvent type is rationalized in terms of solvent structure and coordinating properties. A comparison with 1,10-phenanthroline complexes is investigated and has been found that phen has a larger impact on the transition intensities for these ions. Pyridine has been found most effective in promoting 4f-4f intensity. The results indicate that it is important to consider both the static and dynamic coupling mechanism while analysing the oscillator strength of hypersensitive transition.

  20. Ocean acoustic reverberation tomography.

    Science.gov (United States)

    Dunn, Robert A

    2015-12-01

    Seismic wide-angle imaging using ship-towed acoustic sources and networks of ocean bottom seismographs is a common technique for exploring earth structure beneath the oceans. In these studies, the recorded data are dominated by acoustic waves propagating as reverberations in the water column. For surveys with a small receiver spacing (e.g., ocean acoustic reverberation tomography, is developed that uses the travel times of direct and reflected waves to image ocean acoustic structure. Reverberation tomography offers an alternative approach for determining the structure of the oceans and advancing the understanding of ocean heat content and mixing processes. The technique has the potential for revealing small-scale ocean thermal structure over the entire vertical height of the water column and along long survey profiles or across three-dimensional volumes of the ocean. For realistic experimental geometries and data noise levels, the method can produce images of ocean sound speed on a smaller scale than traditional acoustic tomography.

  1. In situ imaging of the dynamics of photo-induced structural phase transition at high pressures by picosecond acoustic interferometry

    Science.gov (United States)

    Kuriakose, Maju; Chigarev, Nikolay; Raetz, Samuel; Bulou, Alain; Tournat, Vincent; Zerr, Andreas; Gusev, Vitalyi E.

    2017-05-01

    Picosecond acoustic interferometry is used to monitor in time the motion of the phase transition boundary between two water ice phases, VII and VI, coexisting at a pressure of 2.15 GPa when compressed in a diamond anvil cell at room temperature. By analyzing the time-domain Brillouin scattering signals accumulated for a single incidence direction of probe laser pulses, it is possible to access ratios of sound velocity values and of the refractive indices of the involved phases, and to distinguish between the structural phase transition and a recrystallization process. Two-dimensional spatial imaging of the phase transition dynamics indicates that it is initiated by the pump and probe laser pulses, preferentially at the diamond/ice interface. This method should find applications in three-dimensional monitoring with nanometer spatial resolution of the temporal dynamics of low-contrast material inhomogeneities caused by phase transitions or chemical reactions in optically transparent media.

  2. Enhanced delivery of gold nanoparticles by acoustic cavitation for photoacoustic imaging and photothermal therapy

    Science.gov (United States)

    Wang, Yu-Hsin; Liao, Ai-Ho; Lin, Jia-Yu; Lee, Cheng-Ru; Wu, Cheng-Ham; Liu, Tzu-Min; Wang, Churng-Ren; Li, Pai-Chi

    2013-03-01

    Gold-nanorods incorporated with microbubbles (AuMBs) were introduced as a photoacoustic/ultrasound dual- modality contrast agent in our previous study. The application can be extended to theragnosis purpose. With the unique physical characteristics of AuMBs, we propose an enhanced delivery method for the encapsulated particles. For example, laser thermotherapy mediated by plasmonic nanoparticles can be made more effective by using microbubbles as a targeted carrier and acoustic cavitation for enhanced sonoporation. The hypothesis was experimentally tested. Firts, these AuMBs first act as molecular probes with binding to specific ligands. The improved targeting efficacy was macroscopically observed by an ultrasound system. The extended retention of targeted AuMB was observed and recorded for 30 minutes in a CT-26 tumor bearing mouse. Secondly, cavitation induced by time-varying acoustic field was also applied to disrupt the microbubbles and cause increased transient cellular permeability (a.k.a., sonoporation). Multimodal optical microscope based on a Cr:forsterite laser was used to directly observe these effects. The microscope can acquired third-harmonic generation (THG) and two-photon fluorescent (2PF) signals produced by the AuMBs. In vitro examination shows approximately a 60% improvement in terms of fluorescence signals from the cellular uptake of gold nanoparticles after sonoporation treatment. Therefore, we conclude that the controlled release is feasible and can further improve the therapeutic effects of the nanoparticles.

  3. Assessing hepatic fibrosis: comparing the intravoxel incoherent motion in MRI with acoustic radiation force impulse imaging in US

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Chih-Horng; Liang, Po-Chin; Shih, Tiffany Ting-Fang [National Taiwan University Hospital, Department of Medical Imaging, Taipei (China); National Taiwan University College of Medicine, Department of Radiology, Taipei (China); Ho, Ming-Chih; Hu, Rey-Heng; Lai, Hong-Shiee [National Taiwan University Hospital and College of Medicine, Department of Surgery, Taipei (China); Jeng, Yung-Ming [National Taiwan University Hospital and College of Medicine, Department of Pathology, Taipei (China)

    2015-12-15

    This study compared the diagnostic performance of intravoxel incoherent motion (IVIM) in magnetic resonance imaging (MRI) and acoustic radiation force impulse imaging (ARFI) in ultrasound (US) for liver fibrosis (LF) evaluation. A total of 49 patients scheduled for liver surgery were recruited. LF in the non-tumorous liver parenchyma at the right lobe was estimated using a slow diffusion coefficient, fast diffusion coefficient (D{sub fast}), perfusion fraction (f) of the IVIM parameters, the total apparent diffusion coefficient of conventional diffusion-weighted imaging and the shear wave velocity (Vs) of ARFI. LF was graded using the Metavir scoring system on histological examination. The Spearman rank correlation coefficient for correlation and analysis of variance was used for determining difference. The diagnostic performance was compared using receiver operating characteristic curve analysis. LF exhibited significant correlation with the three parameters D{sub fast}, f, and Vs (r = -0.528, -0.337, and 0.481, respectively, P < 0.05). The D{sub fast} values in the F4 group were significantly lower than those in the F0, F1 and F2 groups. D{sub fast} exhibited a non-inferior performance for diagnosing all fibrosis grades compared with that of Vs. Both IVIM and ARFI provide reliable estimations for the noninvasive assessment of LF. (orig.)

  4. Targeting Synthetic Lethal Interactions between Myc and the eIF4F Complex Impedes Tumorigenesis

    Directory of Open Access Journals (Sweden)

    Chen-Ju Lin

    2012-04-01

    Full Text Available The energetically demanding process of translation is linked to multiple signaling events through mTOR-mediated regulation of eukaryotic initiation factor (eIF4F complex assembly. Disrupting mTOR constraints on eIF4F activity can be oncogenic and alter chemotherapy response, making eIF4F an attractive antineoplastic target. Here, we combine a newly developed inducible RNAi platform and pharmacological targeting of eIF4F activity to define a critical role for endogenous eIF4F in Myc-dependent tumor initiation. We find elevated Myc levels are associated with deregulated eIF4F activity in the prelymphomatous stage of the Eμ-Myc lymphoma model. Inhibition of eIF4F is synthetic lethal with elevated Myc in premalignant pre-B/B cells resulting in reduced numbers of cycling pre-B/B cells and delayed tumor onset. At the organismal level, eIF4F suppression affected a subset of normal regenerating cells, but this was well tolerated and rapidly and completely reversible. Therefore, eIF4F is a key Myc client that represents a tumor-specific vulnerability.

  5. Localized Acoustic Surface Modes

    KAUST Repository

    Farhat, Mohamed

    2015-08-04

    We introduce the concept of localized acoustic surface modes (ASMs). We demonstrate that they are induced on a two-dimensional cylindrical rigid surface with subwavelength corrugations under excitation by an incident acoustic plane wave. Our results show that the corrugated rigid surface is acoustically equivalent to a cylindrical scatterer with uniform mass density that can be represented using a Drude-like model. This, indeed, suggests that plasmonic-like acoustic materials can be engineered with potential applications in various areas including sensing, imaging, and cloaking.

  6. Inherited and induced fractures characterized from acoustic and electric boreholes images; Fracturation heritee et induite caracterisee a partir d`images acoustiques et electriques de parois de forages

    Energy Technology Data Exchange (ETDEWEB)

    Dezayes, C.; Genter, A. [Savoie Univ., 73 - Chambery (France); Villemin, T. [Bureau de Recherches Geologiques et Minieres (BRGM), 45 - Orleans (France)

    1996-12-31

    In the framework of a European Geothermal Project, three boreholes were drilled at Soultz-sous-Forets, Rhinegraben, which reached the hot and fractured granitic basement. Fresh water will be injected into one borehole, and recovered hot from the other. To design this reservoir, a knowledge of both the paleo-fracture pattern in the granite and the orientation of the present-day stress field is required. Fracture analysis was carried out on borehole images coming from different boreholes. Two types of logging tools were used to produce theses images: acoustic tools (BHTV, UBI) and electric tools (FMI, FMS). Fractures observed have two origins: pre-existing and induced. Pre-existing fractures showed a symmetrical pattern with a principally N-S direction. These fractures have been created during the tectonic history of the massif since the Visean. This fracture pattern appears to be related to the graben opening which took place during the E-W extensional Oligocene regime. The strike-slip fractures created from other tectonic regimes seem under-sampled by the borehole. However, another fracture set (N50 deg. E) exists but is visible on the acoustic image only. The N-S set is in the present-day horizontal stress direction and locally contains natural fluid. Electric tools are very sensitive to the occurrence of fluid. Fractures with offset are easily detected by acoustic tools. The analysis of induced fractures indicates directly the present-day stress field. Their direction is parallel to the maximum stress in the plane perpendicular to the borehole axis. This direction is N125 deg. E in the EPS1 well and N160 deg. E in the upper part of the GPK1 well, located 500 m apart, but N180 deg. E in the lower part of the GPK1 well and N170 deg. E in GPK2 well. These variations are due to a variation of the present-day stress field at the site scale and at the borehole scale. The results of other in situ present-day stress measurements confirm this variation. This stress

  7. High-speed imaging of an ultrasound-driven bubble in contact with a wall: ``Narcissus'' effect and resolved acoustic streaming

    Science.gov (United States)

    Marmottant, Philippe; Versluis, Michel; de Jong, Nico; Hilgenfeldt, Sascha; Lohse, Detlef

    2006-08-01

    We report microscopic observations of the primary flow oscillation of an acoustically driven bubble in contact with a wall, captured with the ultra high-speed camera Brandaris 128 (Chin et al. 2003). The driving frequency is up to 200 kHz, and the imaging frequency is up to 25 MHz. The details of the bubble motion during an ultrasound cycle are thus resolved, showing a combination of two modes of oscillations: a radius oscillation and a translation oscillation, perpendicular to the wall. This motion is interpreted using the theory of acoustic images to account for the presence of the wall. We conclude that the bubble is subjected to a periodic succession of attractive and repulsive forces, exerted by its own image. Fast-framing recordings of a tracer particle embedded in the liquid around the particle are performed. They fully resolve the acoustic streaming flow induced by the bubble oscillations. This non-linear secondary flow appears as a tiny drift of the particle position cycle after cycle, on top of the primary back and forth oscillation. The high oscillation frequency accounts for a fast average particle velocity, with characteristic timescales in the millisecond range at the lengthscale of the bubble. The features of the bubble motion being resolved, we can apply the acoustic streaming theory near a wall, which provides predictions in agreement with the observed streaming velocity.

  8. ACOUSTICAL IMAGING AND MECHANICAL PROPERTIES OF SOFT ROCK AND MARINE SEDIMENTS

    Energy Technology Data Exchange (ETDEWEB)

    Thurman E. Scott, Jr., Ph.D.; Younane Abousleiman, Ph.D.; Musharraf Zaman, Ph.D., P.E.

    2002-04-30

    Three major goals were accomplished during this phase. First, a study was completed of the effects of stress-induced changes in anisotropic elastic moduli in sandstone. Second, a new method for measuring the anisotropic poroelastic moduli from acoustic data was developed. Third, a series of triaxial experiments were conducted on unconsolidated sands to identify pressure/stress conditions where liquefaction occurs under high confining pressures. Stress-induced changes in anisotropic Young's moduli and shear moduli were observed during deformational pathway experiments. A new method was made for the acquisition of compressional and shear wave velocities along a series of 3-dimensional raypaths through a core sample as it is subjected to deformation. Three different deformational pathway experiments were conducted. During the hydrostatic deformation experiment, little or no anisotropy was observed in either the Young's moduli or shear moduli. Significant deformational anisotropies were observed in both moduli during the uniaxial strain test and the triaxial compression experiment but each had a different nature. During the triaxial experiment the axial and lateral Young's moduli and shear moduli continued to diverge as load was applied. During the uniaxial strain experiment the anisotropy was ''locked in'' early in the loading phase but then remained steady as both the confining pressure and axial stress were applied. A new method for measuring anisotropic Biot's effective stress parameters has also been developed. The method involves measuring the compressional and shear wave velocities in the aforementioned acoustic velocity experiments while varying stress paths. For a stress-induced transversely isotropic medium the acoustic velocity data are utilized to calculate the five independent elastic stiffness components. Once the elastic stiffness components are determined these can be used to calculate the anisotropic Biot

  9. Comparison of analytical and numerical approaches for CT-based aberration correction in transcranial passive acoustic imaging

    Science.gov (United States)

    Jones, Ryan M.; Hynynen, Kullervo

    2016-01-01

    Computed tomography (CT)-based aberration corrections are employed in transcranial ultrasound both for therapy and imaging. In this study, analytical and numerical approaches for calculating aberration corrections based on CT data were compared, with a particular focus on their application to transcranial passive imaging. Two models were investigated: a three-dimensional full-wave numerical model (Connor and Hynynen 2004 IEEE Trans. Biomed. Eng. 51 1693-706) based on the Westervelt equation, and an analytical method (Clement and Hynynen 2002 Ultrasound Med. Biol. 28 617-24) similar to that currently employed by commercial brain therapy systems. Trans-skull time delay corrections calculated from each model were applied to data acquired by a sparse hemispherical (30 cm diameter) receiver array (128 piezoceramic discs: 2.5 mm diameter, 612 kHz center frequency) passively listening through ex vivo human skullcaps (n  =  4) to emissions from a narrow-band, fixed source emitter (1 mm diameter, 516 kHz center frequency). Measurements were taken at various locations within the cranial cavity by moving the source around the field using a three-axis positioning system. Images generated through passive beamforming using CT-based skull corrections were compared with those obtained through an invasive source-based approach, as well as images formed without skull corrections, using the main lobe volume, positional shift, peak sidelobe ratio, and image signal-to-noise ratio as metrics for image quality. For each CT-based model, corrections achieved by allowing for heterogeneous skull acoustical parameters in simulation outperformed the corresponding case where homogeneous parameters were assumed. Of the CT-based methods investigated, the full-wave model provided the best imaging results at the cost of computational complexity. These results highlight the importance of accurately modeling trans-skull propagation when calculating CT-based aberration corrections

  10. Inspection of copper canisters for spent nuclear fuel by means of ultrasound. Ultrasonic imaging, FSW monitoring with acoustic emission

    Energy Technology Data Exchange (ETDEWEB)

    Stepinski, Tadeusz (ed.); Olofsson, Tomas; Wennerstroem, Erik [Uppsala Univ., Dept. of Technical Sciences (Sweden). Signals and Systems

    2006-12-15

    This report contains the research results concerning advanced ultrasound for the inspection of copper canisters for spent nuclear fuel obtained at Signals and Systems, Uppsala University in years 2005/2006. In the first part of the report we propose a concept of monitoring of the friction stir welding (FSW) process by means of acoustic emission (AE) technique. First, we introduce the AE technique and then we present the principle of the system for monitoring the FSW process in cylindrical symmetry specific for the SKB canisters. We propose an omnidirectional circular array of ultrasonic transducers for receiving the AE signals generated by the FSW tool and the releases of the residual stress at canister's circumference. Finally, we review the theory of uniform circular arrays. The second part of the report is concerned with synthetic aperture focusing technique (SAFT) characterized by enhanced spatial resolution. We evaluate three different approaches to perform imaging with less computational cost than that of the extended SAFT (ESAFT) method proposed in our previous reports. First, a sparse version of ESAFT is presented, which solves the reconstruction problem only for a small set of the most probable scatterers in the image. A frequency domain the {omega}-k SAFT algorithm, which relies on the far-field approximation is presented in the second part. Finally, a detailed analysis of the most computationally intense step in the ESAFT and the sparse 2D deconvolution is presented. In the final part of the report we introduce basics of the 3D ultrasonic imaging that has a great potential in the inspection of the FSW welds. We discuss in some detail the three interrelated steps involved in the 3D ultrasonic imaging: data acquisition, 3D reconstruction, and 3D visualization.

  11. Do marine substrates 'look' and 'sound' the same? Supervised classification of multibeam acoustic data using autonomous underwater vehicle images

    Science.gov (United States)

    Lucieer, Vanessa; Hill, Nicole A.; Barrett, Neville S.; Nichol, Scott

    2013-01-01

    In this study we outline the techniques used to transform multibeam acoustic data into spatial layers that can be used for predictive habitat modelling. The results allow us to identify multibeam attributes which may act as potential surrogates for environmental variables that influence biodiversity and define which variables may be reliable for predicting the distribution of species in temperate waters. We explore a method for analysing the spatially coincident multibeam bathymetric and backscatter data from shallow coastal waters to generate spatial data products that relate to the classes derived from fine-scale visual imagery obtained using an autonomous underwater vehicle (AUV). Classifications of the multibeam data are performed for substrate, rugosity and sponge cover. Overall classification accuracies for the classes associated with substratum, rugosity and sponge structure were acceptable for biodiversity assessment applications. Accuracies were highest for rugosity classes at 65%, followed by substratum classes at 64% and then sponge structure classes at 57%. Random forest classifiers at a segmentation scale of 30 performed best in classifying substratum and rugosity, while K-nearest neighbour classifiers performed best for sponge structure classes, with no difference in accuracy between scale 30 and 60. Incorporating backscatter variables using segmentation improved the overall accuracy achieved by the best performing model by between 1% (rugosity) and 9% (substratum) above using topographic variables only in the grid-based analyses. Results suggest that image-based backscatter classification show considerable promise for the interpretation of multibeam sonar data for the production of substrate maps. A particular outcome of this research is to provide appropriate and sufficiently fine-scale physical covariates from the multibeam acoustic data to adequately inform models predicting the distribution of biodiversity on benthic reef habitats.

  12. Modeling the chemical shift of lanthanide 4f electron binding energies

    NARCIS (Netherlands)

    Dorenbos, P.

    2012-01-01

    Lanthanides in compounds can adopt the tetravalent [Xe]4fn?1 (like Ce4+, Pr4+, Tb4+), the trivalent [Xe]4fn (all lanthanides), or the divalent [Xe]4f n+1 configuration (like Eu2+, Yb2+, Sm2+, Tm2+). The 4f-electron binding energy depends on the charge Q of the lanthanide ion and its chemical

  13. Interference effects in the autoionization of 4F7H and 6DNI states of Barium

    NARCIS (Netherlands)

    van Leeuwen, R.; Ubachs, W.M.G.; Hogervorst, W.; Aymar, M.; Luckoenig, E.

    1995-01-01

    In a two-step pulsed laser experiment 4f5/27h J=4,5,6, autoionizing levels of Ba were excited. The 4f5/27h levels interact with 6d5/2ni levels resulting in complex interference patterns. The excitation spectra were calculated using the eigenchannel R-matrix method in combination with multichannel

  14. Experimental Investigation on the Fracture Behavior of Black Shale by Acoustic Emission Monitoring and CT Image Analysis during Uniaxial Compression

    Science.gov (United States)

    Wang, Y.; Li, C. H.; Hu, Y. Z.

    2018-01-01

    Plenty of mechanical experiments have been done to investigate the deformation and failure characteristics of shale; however, the anisotropic failure mechanism has not been well studied. Here, laboratory Uniaxial Compressive Strength (UCS) tests on cylindrical shale samples obtained by drilling at different inclinations to bedding plane were performed. The failure behaviors of the shale samples were studied by real-time acoustic emission (AE) monitoring and post-test X-ray computer tomography (CT) analysis. The experimental results suggest that the pronounced bedding planes of shale have a great influence on the mechanical properties and AE patterns. The AE counts and AE cumulative energy release curves clearly demonstrate different morphology, and the `U' shaped curve relationship between the AE counts, AE cumulative energy release and bedding inclination was first documented. The post-test CT image analysis shows the crack patterns via 2D image reconstructions, an index of stimulated fracture density is defined to represent the anisotropic failure mode of shale. What is more, the most striking finding is that the AE monitoring results are in good agreement with the CT analysis. The structural difference in the shale sample is the controlling factor resulting in the anisotropy of AE patterns. The pronounced bedding structure in the shale formation results in an anisotropy of elasticity, strength, and AE information from which the changes in strength dominate the entire failure pattern of the shale samples.

  15. Architectural acoustics

    National Research Council Canada - National Science Library

    Long, Marshall

    2014-01-01

    .... Beginning with a brief history, it reviews the fundamentals of acoustics, human perception and reaction to sound, acoustic noise measurements, noise metrics, and environmental noise characterization...

  16. Nonlinear acoustic enhancement in photoacoustic imaging with wideband absorptive nanoemulsion beads

    Science.gov (United States)

    Wei, Chen-wei; Lombardo, Michael; Xia, Jinjun; Pelivanov, Ivan; Perez, Camilo; Larson-Smith, Kjersta; Matula, Thomas J.; Pozzo, Danilo; O'Donnell, Matthew

    2014-03-01

    A nanoemulsion contrast agent with a perfluorohexane core and optically absorptive gold nanospheres (GNSs) assembled on the surface, is presented to improve the specificity of photoacoustic (PA) molecular imaging in differentiating targeted cells or aberrant regions from heterogeneous background signals. Compared to distributed GNSs, clustered GNSs at the emulsion oil-water interface produce a red-shifted and broadened absorption spectrum, exhibiting fairly high absorption in the near-infrared region commonly used for deep tissue imaging. Above a certain laser irradiation fluence threshold, a phase transition creating a microbubble in the emulsion core leads to more than 10 times stronger PA signals compared with conventional thermal-expansion-induced PA signals. These signals are also strongly non-linear, as verified by a differential scheme using recorded PA images at different laser fluences. Assuming a linear relation between laser fluence and the PA signal amplitude, differential processing results in nearly perfect suppression of linear sources, but retains a significant residue for the non-linear nanoemulsion with more than 35 dB enhancement. This result demonstrates that contrast specificity can be improved using the nanoemulsion as a targeting agent in PA molecular imaging by suppressing all background signals related to a linear PA response. Furthermore, combined with a system providing simultaneous laser/ultrasound excitation, cavitation-generated bubbles have the potential to be a highly specific contrast agent for ultrasound molecular imaging and harmonic imaging, as well as a targeted means for noninvasive ultrasound-based therapies.

  17. A chimeric design of heterospin 2p-3d, 2p-4f, and 2p-3d-4f complexes using a novel family of paramagnetic dissymmetric compartmental ligands.

    Science.gov (United States)

    Patrascu, Andrei A; Calancea, Sergiu; Briganti, Matteo; Soriano, Stéphane; Madalan, Augustin M; Cassaro, Rafael A Allão; Caneschi, Andrea; Totti, Federico; Vaz, Maria G F; Andruh, Marius

    2017-06-13

    End-off bicompartmental ligands bearing a nitronyl-nitroxide arm have been designed for synthesizing various heterospin molecular systems. These ligands can selectively interact with 3d and 4f metal ions, leading to 2p-4f, 2p-3d, and 2p-3d-4f complexes. The magnetic properties of the 2p-4f and 2p-3d-4f complexes have been investigated and rationalized by theoretical calculations.

  18. Development of Acoustic Model-Based Iterative Reconstruction Technique for Thick-Concrete Imaging

    Energy Technology Data Exchange (ETDEWEB)

    Almansouri, Hani [Purdue University; Clayton, Dwight A [ORNL; Kisner, Roger A [ORNL; Polsky, Yarom [ORNL; Bouman, Charlie [Purdue University; Santos-Villalobos, Hector J [ORNL

    2016-01-01

    Ultrasound signals have been used extensively for non-destructive evaluation (NDE). However, typical reconstruction techniques, such as the synthetic aperture focusing technique (SAFT), are limited to quasi-homogenous thin media. New ultrasonic systems and reconstruction algorithms are in need for one-sided NDE of non-homogenous thick objects. An application example space is imaging of reinforced concrete structures for commercial nuclear power plants (NPPs). These structures provide important foundation, support, shielding, and containment functions. Identification and management of aging and degradation of concrete structures is fundamental to the proposed long-term operation of NPPs. Another example is geothermal and oil/gas production wells. These multi-layered structures are composed of steel, cement, and several types of soil and rocks. Ultrasound systems with greater penetration range and image quality will allow for better monitoring of the well's health and prediction of high-pressure hydraulic fracturing of the rock. These application challenges need to be addressed with an integrated imaging approach, where the application, hardware, and reconstruction software are highly integrated and optimized. Therefore, we are developing an ultrasonic system with Model-Based Iterative Reconstruction (MBIR) as the image reconstruction backbone. As the first implementation of MBIR for ultrasonic signals, this paper document the first implementation of the algorithm and show reconstruction results for synthetically generated data.

  19. Development of acoustic model-based iterative reconstruction technique for thick-concrete imaging

    Science.gov (United States)

    Almansouri, Hani; Clayton, Dwight; Kisner, Roger; Polsky, Yarom; Bouman, Charles; Santos-Villalobos, Hector

    2016-02-01

    Ultrasound signals have been used extensively for non-destructive evaluation (NDE). However, typical reconstruction techniques, such as the synthetic aperture focusing technique (SAFT), are limited to quasi-homogenous thin media. New ultrasonic systems and reconstruction algorithms are in need for one-sided NDE of non-homogenous thick objects. An application example space is imaging of reinforced concrete structures for commercial nuclear power plants (NPPs). These structures provide important foundation, support, shielding, and containment functions. Identification and management of aging and degradation of concrete structures is fundamental to the proposed long-term operation of NPPs. Another example is geothermal and oil/gas production wells. These multi-layered structures are composed of steel, cement, and several types of soil and rocks. Ultrasound systems with greater penetration range and image quality will allow for better monitoring of the well's health and prediction of high-pressure hydraulic fracturing of the rock. These application challenges need to be addressed with an integrated imaging approach, where the application, hardware, and reconstruction software are highly integrated and optimized. Therefore, we are developing an ultrasonic system with Model-Based Iterative Reconstruction (MBIR) as the image reconstruction backbone. As the first implementation of MBIR for ultrasonic signals, this paper document the first implementation of the algorithm and show reconstruction results for synthetically generated data.1

  20. Combined acoustic-photoacoustic and fluorescence imaging catheter for the detection of the atherosclerotic plaque

    Science.gov (United States)

    Abran, Maxime; Matteau-Pelletier, Carl; Zerouali-Boukhal, Karim; Tardif, Jean-Claude; Lesage, Frédéric

    2011-03-01

    In industrialized countries, cardiovascular diseases remain the main cause of mortality. The detection of atherosclerosis and its associated plaque using imaging techniques allows studying the efficacy of new drugs in vivo. Intravascular ultrasound (IVUS) imaging has been demonstrated to be a powerful tool to uncover structural information of atherosclerotic plaques. Recently, intravascular photoacoustic (IVPA) has been combined with IVUS imaging to add functional and/or molecular information. The IVPA/IVUS combination has been demonstrated in phantoms and ex vivo tissues to provide relevant information about the composition of the plaque, as well as its vulnerability. In this work, we extend previous work by developing a combined IVPA/IVUS system using a rotating ultrasound transducer in a catheter to which an optical fiber is attached. In addition, a third modality was included through fluorescence detection in the same fiber at a distinct wavelength from PA, opening the door to complementary information using fluorescence activatable probes. Cylindrical silicon phantoms with inclusions containing fluorophores or ink were used to validate the system. Bleaching of the fluorophore by the pulsed laser used for photoacoustic was quantified. IVUS images were obtained continuously and used to co-register photoacoustic and fluorescence signals.

  1. Development of Acoustic Model-Based Iterative Reconstruction Technique for Thick-Concrete Imaging

    Energy Technology Data Exchange (ETDEWEB)

    Almansouri, Hani [Purdue University; Clayton, Dwight A [ORNL; Kisner, Roger A [ORNL; Polsky, Yarom [ORNL; Bouman, Charlie [Purdue University; Santos-Villalobos, Hector J [ORNL

    2015-01-01

    Ultrasound signals have been used extensively for non-destructive evaluation (NDE). However, typical reconstruction techniques, such as the synthetic aperture focusing technique (SAFT), are limited to quasi-homogenous thin media. New ultrasonic systems and reconstruction algorithms are in need for one-sided NDE of non-homogenous thick objects. An application example space is imaging of reinforced concrete structures for commercial nuclear power plants (NPPs). These structures provide important foundation, support, shielding, and containment functions. Identification and management of aging and degradation of concrete structures is fundamental to the proposed long-term operation of NPPs. Another example is geothermal and oil/gas production wells. These multi-layered structures are composed of steel, cement, and several types of soil and rocks. Ultrasound systems with greater penetration range and image quality will allow for better monitoring of the well s health and prediction of high-pressure hydraulic fracturing of the rock. These application challenges need to be addressed with an integrated imaging approach, where the application, hardware, and reconstruction software are highly integrated and optimized. Therefore, we are developing an ultrasonic system with Model-Based Iterative Reconstruction (MBIR) as the image reconstruction backbone. As the first implementation of MBIR for ultrasonic signals, this paper document the first implementation of the algorithm and show reconstruction results for synthetically generated data.

  2. Virtual Acoustics

    Science.gov (United States)

    Lokki, Tapio; Savioja, Lauri

    The term virtual acoustics is often applied when sound signal is processed to contain features of a simulated acoustical space and sound is spatially reproduced either with binaural or with multichannel techniques. Therefore, virtual acoustics consists of spatial sound reproduction and room acoustics modeling.

  3. Poliovirus proteinase 2A induces cleavage of eucaryotic initiation factor 4F polypeptide p220.

    Science.gov (United States)

    Kräusslich, H G; Nicklin, M J; Toyoda, H; Etchison, D; Wimmer, E

    1987-01-01

    Poliovirus infection of HeLa cells induces rapid shutoff of host protein synthesis, whereas translation of poliovirus RNA is not inhibited. It is presumed that shutoff is the result of proteolytic cleavage of component p220 of eucaryotic initiation factor 4F. To study whether poliovirus proteinase 2A is involved in this cleavage, we translated synthetic RNAs that contained the coding region for poliovirus-specific polypeptides P1 and 2A in vitro and assayed for cleavage of p220. We report here that cleavage of p220 occurred in all cases when active proteinase 2A was translated and that disruption of the coding sequence of 2A by linker insertion or deletion prevented processing of p220 in vitro. Activity of 2A was determined by its ability to cleave at the P1-P2 site of a segment of the poliovirus polyprotein. We also constructed a plasmid in which the 3'-most 500 nucleotides of the nontranslated region of encephalomyocarditis virus were linked to the coding sequence for poliovirus polypeptide 2A. Translation of the RNA transcript of this clone was very efficient and yielded a fusion protein that included 2A; this polypeptide also induced cleavage of p220. In vitro translation in the presence of antibodies against 2A specifically inhibited processing of p220, whereas incubation of in vitro translation products with antibodies against 2A after translation was completed did not prevent proteolysis of p220. Images PMID:3039165

  4. Virtual touch tissue quantification of acoustic radiation force impulse: a new ultrasound elastic imaging in the diagnosis of thyroid nodules.

    Directory of Open Access Journals (Sweden)

    Yi-Feng Zhang

    Full Text Available OBJECTIVE: Virtual touch tissue quantification (VTQ of acoustic radiation force impulse (ARFI is a new quantitative technique to measure tissue stiffness. The study was aimed to assess the usefulness of VTQ in the diagnosis of thyroid nodules. METHODS: 173 pathologically proven thyroid nodules in 142 patients were included and all were examined by conventional ultrasound (US, conventional elasticity imaging (EI and VTQ of ARFI. The tissue stiffness for VTQ was expressed as shear wave velocity (SWV (m/s. Receiver-operating characteristic curve (ROC analyses were performed to assess the diagnostic performance. Intra- and inter-observer reproducibility of VTQ measurement was assessed. RESULTS: The SWVs of benign and malignant thyroid nodules were 2.34±1.17 m/s (range: 0.61-9.00 m/s and 4.82±2.53 m/s (range: 2.32-9.00 m/s respectively (P20 mm and lowest for those ≤10 mm. The correlation coefficients were 0.904 for intraobserver measurement and 0.864 for interobserver measurement. CONCLUSIONS: VTQ of ARFI provides quantitative and reproducible information about the tissue stiffness, which is useful for the differentiation between benign and malignant thyroid nodules. The diagnostic performance of VTQ is higher than that of conventional EI.

  5. Acoustic radiation force impulse imaging (ARFI) for differentiation of benign and malignant thyroid nodules--A meta-analysis.

    Science.gov (United States)

    Zhan, Jia; Jin, Jia-Mei; Diao, Xue-Hong; Chen, Yue

    2015-11-01

    Work-up of thyroid nodules remains challenging. Acoustic radiation force impulse imaging (ARFI)-generated shear wave elastography, which can measure quantitatively tissue stiffness (virtual touch tissue quantification) is used as a complement to conventional sonography for improving the diagnosis of thyroid nodules. This meta-analysis was performed to expand on a previous meta-analysis to assess the diagnostic power of ARFI in differentiating benign and malignant thyroid nodules. The MEDLINE, PubMed, SpringerLink databases up to December 31, 2014, were searched. The pooled sensitivity, specificity, and summary receiver operating characteristic curve were obtained from individual studies with a random effects model. Sixteen studies that included a total of 2436 nodules in 2147 patients for ARFI studies were analyzed. The overall mean sensitivity and specificity of ARFI for differentiation of thyroid nodules were 0.80 (95% confidence interval [CI], 0.73-0.87) and 0.85 (95% CI, 0.80-0.90), respectively. A significant heterogeneity was found for both sensitivity and specificity of the different studies (P<0.001). The area under the curve for the ARFI was 0.91. ARFI has high sensitivity and specificity for identification of thyroid. This technique might be useful to select patients with thyroid nodules for surgery. Copyright © 2015. Published by Elsevier Ireland Ltd.

  6. Tetranuclear 3d/4f coordination clusters as highly efficient catalysts for Friedel Crafts alkylation

    OpenAIRE

    Griffiths, Kieran; Kumar, Prashant; Akien, Geoffrey R.; Chilton, Nicholas F; Abdul-Sada, Alaa; Tizzard, Graham J; Simon J. Coles; Kostakis, George E.

    2016-01-01

    A series of custom-designed, high yield, isoskeletal tetranuclear Zn/4f coordination clusters showing high efficiency as catalysts with low catalytic loadings in Friedel-Crafts alkylation are described for the first time. The possibility of altering the 4f centers in these catalysts without altering the core topology allows us to further confirm their stability via EPR and NMR, as well to gain insights into the plausible reaction mechanism, showcasing the usefulness of these bimetallic system...

  7. Tetranuclear Zn/4f coordination clusters as highly efficient catalysts for Friedel–Crafts alkylation

    OpenAIRE

    Griffiths, Kieran; Kumar, Prashant; Akien, Geoffrey R.; Chilton, Nicholas F; Abdul-Sada, Alaa; Tizzard, Graham; Coles, Simon; Kostakis, George E.

    2016-01-01

    A series of custom-designed, high yield, isoskeletal tetranuclear Zn/4f coordination clusters showing high efficiency as catalysts with low catalytic loadings in Friedel–Crafts alkylation are described for the first time. The possibility of altering the 4f centers in these catalysts without altering the core topology allows us to further confirm their stability via EPR and NMR, as well to gain insights into the plausible reaction mechanism, showcasing the usefulness of these bimetallic system...

  8. Acoustic performance of mesh compression paddles for a multimodality breast imaging system.

    Science.gov (United States)

    LeCarpentier, Gerald L; Goodsitt, Mitchell M; Verweij, Sacha; Li, Jie; Padilla, Frederic R; Carson, Paul L

    2014-07-01

    A system incorporating automated 3-D ultrasound and digital X-ray tomosynthesis is being developed for improved breast lesion detection and characterization. The goal of this work is to develop and test candidates for a dual-modality mesh compression paddle. A Computerized Imaging Reference Systems (Norfork, VA, USA) ultrasound phantom with tilted low-contrast cylindrical objects was used. Polyester mesh fabrics (1- and 2-mm spacing), a high-density polyethylene filament grid (Dyneema, DSM Dyneema, Stanley, NC, USA) and a solid polymethylpentene (TPX; Mitsui Plastics, Inc., White Plains, NY) paddle were compared with no overlying structures using a GE Logic 9 with M12L transducer. A viscous gel provided coupling. The phantom was scanned 10 times over 9 cm for each configuration. Image volumes were analyzed for signal strength, contrast and contrast-to-noise ratio. X-ray tests confirmed X-ray transparency for all materials. By all measures, both mesh fabrics outperformed TPX and Dyneema, and there were essentially no differences between 2-mm mesh and unobstructed configurations. Copyright © 2014 World Federation for Ultrasound in Medicine & Biology. Published by Elsevier Inc. All rights reserved.

  9. CYP4F18-Deficient Neutrophils Exhibit Increased Chemotaxis to Complement Component C5a

    Directory of Open Access Journals (Sweden)

    Rachel Vaivoda

    2015-01-01

    Full Text Available CYP4Fs were first identified as enzymes that catalyze hydroxylation of leukotriene B4 (LTB4. CYP4F18 has an unusual expression in neutrophils and was predicted to play a role in regulating LTB4-dependent inflammation. We compared chemotaxis of wild-type and Cyp4f18 knockout neutrophils using an in vitro assay. There was no significant difference in the chemotactic response to LTB4, but the response to complement component C5a increased 1.9–2.25-fold in knockout cells compared to wild-type (P < 0.01. This increase was still observed when neutrophils were treated with inhibitors of eicosanoid synthesis. There were no changes in expression of other CYP4 enzymes in knockout neutrophils that might compensate for loss of CYP4F18 or lead to differences in activity. A mouse model of dextran sodium sulfate colitis was used to investigate the consequences of increased C5a-dependent chemotaxis in vivo, but there was no significant difference in weight loss, disease activity, or colonic tissue myeloperoxidase between wild-type and Cyp4f18 knockout mice. This study demonstrates the limitations of inferring CYP4F function based on an ability to use LTB4 as a substrate, points to expanding roles for CYP4F enzymes in immune regulation, and underscores the in vivo challenges of CYP knockout studies.

  10. Communication Acoustics

    DEFF Research Database (Denmark)

    Blauert, Jens

    Communication Acoustics deals with the fundamentals of those areas of acoustics which are related to modern communication technologies. Due to the advent of digital signal processing and recording in acoustics, these areas have enjoyed an enormous upswing during the last 4 decades. The book chapt......: acoustics, cognitive science, speech science, and communication technology.......Communication Acoustics deals with the fundamentals of those areas of acoustics which are related to modern communication technologies. Due to the advent of digital signal processing and recording in acoustics, these areas have enjoyed an enormous upswing during the last 4 decades. The book...... the book a source of valuable information for those who want to improve or refresh their knowledge in the field of communication acoustics - and to work their way deeper into it. Due to its interdisciplinary character Communication Acoustics is bound to attract readers from many different areas, such as...

  11. Communication Acoustics

    DEFF Research Database (Denmark)

    Blauert, Jens

    Communication Acoustics deals with the fundamentals of those areas of acoustics which are related to modern communication technologies. Due to the advent of digital signal processing and recording in acoustics, these areas have enjoyed an enormous upswing during the last 4 decades. The book...... the book a source of valuable information for those who want to improve or refresh their knowledge in the field of communication acoustics - and to work their way deeper into it. Due to its interdisciplinary character Communication Acoustics is bound to attract readers from many different areas, such as......: acoustics, cognitive science, speech science, and communication technology....

  12. Communication Acoustics

    DEFF Research Database (Denmark)

    Blauert, Jens

    the book a source of valuable information for those who want to improve or refresh their knowledge in the field of communication acoustics - and to work their way deeper into it. Due to its interdisciplinary character Communication Acoustics is bound to attract readers from many different areas, such as......Communication Acoustics deals with the fundamentals of those areas of acoustics which are related to modern communication technologies. Due to the advent of digital signal processing and recording in acoustics, these areas have enjoyed an enormous upswing during the last 4 decades. The book......: acoustics, cognitive science, speech science, and communication technology....

  13. Communication Acoustics

    DEFF Research Database (Denmark)

    Blauert, Jens

    Communication Acoustics deals with the fundamentals of those areas of acoustics which are related to modern communication technologies. Due to the advent of digital signal processing and recording in acoustics, these areas have enjoyed an enormous upswing during the last 4 decades. The book......: acoustics, cognitive science, speech science, and communication technology....... the book a source of valuable information for those who want to improve or refresh their knowledge in the field of communication acoustics - and to work their way deeper into it. Due to its interdisciplinary character Communication Acoustics is bound to attract readers from many different areas, such as...

  14. Photoacoustic imaging with an acoustic lens detects prostate cancer cells labeled with PSMA-targeting near-infrared dye-conjugates

    Science.gov (United States)

    Dogra, Vikram; Chinni, Bhargava; Singh, Shalini; Schmitthenner, Hans; Rao, Navalgund; Krolewski, John J.; Nastiuk, Kent L.

    2016-06-01

    There is an urgent need for sensitive and specific tools to accurately image early stage, organ-confined human prostate cancers to facilitate active surveillance and reduce unnecessary treatment. Recently, we developed an acoustic lens that enhances the sensitivity of photoacoustic imaging. Here, we report the use of this device in conjunction with two molecular imaging agents that specifically target the prostate-specific membrane antigen (PSMA) expressed on the tumor cell surface of most prostate cancers. We demonstrate successful imaging of phantoms containing cancer cells labeled with either of two different PSMA-targeting agents, the ribonucleic acid aptamer A10-3.2 and a urea-based peptidomimetic inhibitor, each linked to the near-infrared dye IRDye800CW. By specifically targeting cells with these agents linked to a dye chosen for optimal signal, we are able to discriminate prostate cancer cells that express PSMA.

  15. Acoustic field modulation in regenerators

    Science.gov (United States)

    Hu, J. Y.; Wang, W.; Luo, E. C.; Chen, Y. Y.

    2016-12-01

    The regenerator is a key component that transfers energy between heat and work. The conversion efficiency is significantly influenced by the acoustic field in the regenerator. Much effort has been spent to quantitatively determine this influence, but few comprehensive experimental verifications have been performed because of difficulties in modulating and measuring the acoustic field. In this paper, a method requiring two compressors is introduced and theoretically investigated that achieves acoustic field modulation in the regenerator. One compressor outputs the acoustic power for the regenerator; the other acts as a phase shifter. A RC load dissipates the acoustic power out of both the regenerator and the latter compressor. The acoustic field can be modulated by adjusting the current in the two compressors and opening the RC load. The acoustic field is measured with pressure sensors instead of flow-field imaging equipment, thereby greatly simplifying the experiment.

  16. Controlling sound with acoustic metamaterials

    DEFF Research Database (Denmark)

    Cummer, Steven A. ; Christensen, Johan; Alù, Andrea

    2016-01-01

    -scale metamaterial structures and converting laboratory experiments into useful devices. In this Review, we outline the designs and properties of materials with unusual acoustic parameters (for example, negative refractive index), discuss examples of extreme manipulation of sound and, finally, provide an overview......Acoustic metamaterials can manipulate and control sound waves in ways that are not possible in conventional materials. Metamaterials with zero, or even negative, refractive index for sound offer new possibilities for acoustic imaging and for the control of sound at subwavelength scales....... The combination of transformation acoustics theory and highly anisotropic acoustic metamaterials enables precise control over the deformation of sound fields, which can be used, for example, to hide or cloak objects from incident acoustic energy. Active acoustic metamaterials use external control to create...

  17. Experiments for possible hydroacoustic discrimination of free-swimming juvenile gadoid fish by analysis of broadband pulse spectra as well as 3D fish position form video images and split beam acoustics

    DEFF Research Database (Denmark)

    Lundgren, Bo; Nielsen, J. Rasmus

    2002-01-01

    Measurements were made of the broad-bandwidth (80–220 kHz) acoustic backscattering from free-swimming juvenile gadoids at various orientations and positions in an acoustic beam, under controlled conditions. The experimental apparatus consisted of a stereo-video camera system, a broad-bandwidth ec......Measurements were made of the broad-bandwidth (80–220 kHz) acoustic backscattering from free-swimming juvenile gadoids at various orientations and positions in an acoustic beam, under controlled conditions. The experimental apparatus consisted of a stereo-video camera system, a broad......, alignment of acoustic and optical-reference frames, and automatic position-fitting of fish models to manually marked fix-points on fish images. The software also performs Fourier spectrum analysis and pulse-shape analysis of broad-bandwidth echoes. Therefore, several measurement series on free...

  18. Acoustic Neuroma

    Science.gov (United States)

    An acoustic neuroma is a benign tumor that develops on the nerve that connects the ear to the brain. ... can press against the brain, becoming life-threatening. Acoustic neuroma can be difficult to diagnose, because the ...

  19. Apolipoprotein A-I mimetic peptide 4F blocks sphingomyelinase-induced LDL aggregation

    DEFF Research Database (Denmark)

    Nguyen, Su Duy; Javanainen, Matti; Rissanen, Sami

    2015-01-01

    Lipolytic modification of LDL particles by SMase generates LDL aggregates with a strong affinity for human arterial proteoglycans and may so enhance LDL retention in the arterial wall. Here, we evaluated the effects of apoA-I mimetic peptide 4F on structural and functional properties of the SMase......-modified LDL particles. LDL particles with and without 4F were incubated with SMase, after which their aggregation, structure, and proteoglycan binding were analyzed. At a molar ratio of L-4F to apoB-100 of 2.5 to 20:1, 4F dose-dependently inhibited SMase-induced LDL aggregation. At a molar ratio of 20......:1, SMase-induced aggregation was fully blocked. Binding of 4F to LDL particles inhibited SMase-induced hydrolysis of LDL by 10% and prevented SMase-induced LDL aggregation. In addition, the binding of the SMase-modified LDL particles to human aortic proteoglycans was dose-dependently inhibited...

  20. m6A Facilitates eIF4F-Independent mRNA Translation.

    Science.gov (United States)

    Coots, Ryan A; Liu, Xiao-Min; Mao, Yuanhui; Dong, Leiming; Zhou, Jun; Wan, Ji; Zhang, Xingqian; Qian, Shu-Bing

    2017-10-23

    In eukaryotic cells, protein synthesis typically begins with the binding of eIF4F to the 7-methylguanylate (m7G) cap found on the 5' end of the majority of mRNAs. Surprisingly, overall translational output remains robust under eIF4F inhibition. The broad spectrum of eIF4F-resistant translatomes is incompatible with cap-independent translation mediated by internal ribosome entry sites (IRESs). Here, we report that N6-methyladenosine (m6A) facilitates mRNA translation that is resistant to eIF4F inactivation. Depletion of the methyltransferase METTL3 selectively inhibits translation of mRNAs bearing 5' UTR methylation, but not mRNAs with 5' terminal oligopyrimidine (TOP) elements. We identify ABCF1 as a critical mediator of m6A-promoted translation under both stress and physiological conditions. Supporting the role of ABCF1 in m6A-facilitated mRNA translation, ABCF1-sensitive transcripts largely overlap with METTL3-dependent mRNA targets. By illustrating the scope and mechanism of eIF4F-independent mRNA translation, these findings reshape our current perceptions of cellular translational pathways. Copyright © 2017 Elsevier Inc. All rights reserved.

  1. RADIATION ACOUSTICS

    OpenAIRE

    Lyamshev, L.

    1990-01-01

    Radiation acoustics is a new branch of acoustics. Its' fundamentals are lying in the research of acoustical effects due to the interaction of a radiation with matter. The sound excitation in liquids and solids by modulated or pulsed particle beams (electron, proton, ion beams, γ-radiation and single high-energy elementary particles) and some practical applications are discussed.

  2. Pou4f2-GFP knock-in mouse line: A model for studying retinal ganglion cell development.

    Science.gov (United States)

    Zheng, Dongwang; Yang, Xiaoyan; Sheng, Donglai; Yu, Dongliang; Liang, Guoqing; Guo, Luming; Xu, Mei; Hu, Xu; He, Daqiang; Yang, Yang; Wang, Yuying

    2016-10-01

    Pou4f2 acts as a key node in the comprehensive and step-wise gene regulatory network (GRN) and regulates the development of retinal ganglion cells (RGCs). Accordingly, deletion of Pou4f2 results in RGC axon defects and apoptosis. To investigate the GRN involved in RGC regeneration, we generated a mouse line with a POU4F2-green fluorescent protein (GFP) fusion protein expressed in RGCs. Co-localization of POU4F2 and GFP in the retina and brain of Pou4f2-GFP/+ heterozygote mice was confirmed using immunofluorescence analysis. Compared with those in wild-type mice, the expression patterns of POU4F2 and POU4F1 and the co-expression patterns of ISL1 and POU4F2 were unaffected in Pou4f2-GFP/GFP homozygote mice. Moreover, the quantification of RGCs showed no significant difference between Pou4f2-GFP/GFP homozygote and wild-type mice. These results demonstrated that the development of RGCs in Pou4f2-GFP/GFP homozygote mice was the same as in wild-type mice. Thus, the present Pou4f2-GFP knock-in mouse line is a useful tool for further studies on the differentiation and regeneration of RGCs. © 2016 Wiley Periodicals, Inc.

  3. Comments on the thermoelectric power of intermetallic rare-earth compounds with well localized 4f shells

    Energy Technology Data Exchange (ETDEWEB)

    Szukiel, A.E., E-mail: ghbsqx@gmail.com

    2016-05-01

    The anomalous temperature variation of the thermoelectric power in the metallic rare-earth compounds with well-localized 4f shells is sometimes interpreted as resulting from the conduction electrons scattering in the Born approximation on the acoustic phonons and on the localized spins in the s–f exchange interaction. Such an interpretation relies on the results of some theoretical works where the sign reversal and the maxima of the thermoelectric power were obtained within these simple models. In the present paper we prove that neither the electron–phonon scattering nor the magnetic s–f scattering in the Born approximation (nor both of them) do lead to the effects mentioned above. - Highlights: • We reveal an errant theory for thermopower (TEP) of f-electron systems. • The theory pretends to explain the TEP maxima and its sign changes. • The theory was used in many works to interpret the TEP experiment. • We correct the errors, presenting detailed and strict calculations. • Electron-phonon and s-f scattering in Born approximation give only nearly linear TEP.

  4. 4f hybridization and band dispersion in gadolinium thin films and compounds

    Energy Technology Data Exchange (ETDEWEB)

    Komesu, Takashi; Jeong, H.K.; Dowben, P.A. [Department of Physics and Astronomy, Nebraska Center for Materials and Nanoscience, University of Nebraska-Lincoln, Lincoln, NE (United States); Wooton, David; Petrosky, J. [Air Force Institute of Technology, Wright Patterson Air Force Base, OH (United States); Losovyj, Ya.B. [Department of Physics and Astronomy, Nebraska Center for Materials and Nanoscience, University of Nebraska-Lincoln, Lincoln, NE (United States); Center for Advanced Microstructures and Devices, Louisiana State University, Jefferson Highway, Baton Rouge, LA (United States); Crain, J.N.; Himpse, F.J. [Department of Physics, University of Wisconsin-Madison, Madison, WI (United States); Bissen, M. [Synchrotron Radiation Center, Stoughton, WI (United States); Tang, Jinke; Wang, Wendong [Department of Physics and Astronomy, University of Wyoming, Laramie, WY (United States); Yakovkin, I.N. [National Academy of Science of Ukraine, Institute of Physics, Kiev (Ukraine)

    2009-05-15

    There is interplay between intra-atomic orbital hybridization and extra-atomic hybridization in various gadolinium systems, which affects magnetic coupling and electron itinerancy (localization). The results do not always follow expectation. The experimental band structure of thin Gd(0001) films, grown on the Mo(112) surface, along the anti {gamma}- anti M does not agree with expectations even qualitatively. In particular, the dispersion of the gadolinium band, with strong 5d weight near 2 eV binding energy provides considerable evidence to support the case for 4f-5d hybridization, with increasing 5d localization. On the other hand, there is also evidence of extra-atomic Gd 4f hybridization leading band dispersion in the occupied 4f levels in Gd{sub 2}O{sub 3}. (copyright 2009 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  5. Magnetic x-ray linear dichroism in resonant and non-resonant Gd 4f photoemission

    Energy Technology Data Exchange (ETDEWEB)

    Mishra, S.; Gammon, W.J.; Pappas, D.P. [Virginia Commonwealth Univ., Richmond, VA (United States)] [and others

    1997-04-01

    The enhancement of the magnetic linear dichroism in resonant 4f photoemission (MLDRPE) is studied from a 50 monolayer film of Gd/Y(0001). The ALS at beamline 7.0.1 provided the source of linearly polarized x-rays used in this study. The polarized light was incident at an angle of 30 degrees relative to the film plane, and the sample magnetization was perpendicular to the photon polarization. The linear dichroism of the 4f core levels is measured as the photon energy is tuned through the 4d-4f resonance. The authors find that the MLDRPE asymmetry is strongest at the resonance. Near the threshold the asymmetry has several features which are out of phase with the fine structure of the total yield.

  6. Synthesis and evaluation of 4-[F-18]fluoro thalidomide for the in vivo studies of angiogenesis

    Energy Technology Data Exchange (ETDEWEB)

    Kim, D. H.; Choi, Y. S.; Jeong, K. H.; Lee, K. H.; Choi, Y.; Kim, B. T. [Samsung Medical Center, Seoul (Korea, Republic of)

    2005-07-01

    Thalidomide has been recently rediscovered for its possible utility as an antitumor agent, although it was marketed as a sedative in the 1950s and later found to be a potent teratogen. In this study, therefore, F-18 labeled thalidomide was synthesized and evaluated for the in vivo studies of angiogenesis. 4-[F-18]Fluoro thalidomide ([F-18]1) was prepared by labeling of 4-trimethylammonium thalidomide triflate with TBA[F-18]F in DMSO (90 .deg. C, 10 min) and purified by HPLC. The triflate salt was prepared from 3-fluoro phthalic anhydride in 3 steps. [F-18]1 was incubated with HUVEC cells at 37 .deg. C for 15, 30, 60, and 120 min, respectively. Dynamic PET images of [F-18]1 was obtained in mice implanted with LLC cells. In vitro metabolism study of [F-18]1 was carried out using mouse, rabbit, or human liver microsomes in the presence of NADPH, and the metabolites obtained from the mouse liver microsomal incubation of 1 were analyzed using LC-MS. Radiochemical yield of [F-18]1 was 50-60%, and the specific activity was 42-120 GBq/imol. The HUVEC cell uptake of [F-18]1 increased with time (100% at 15 min and 241% at 120 min). PET images showed that the radioactivity was accumulated in the liver, the kidneys and the bladder of the mice, and brain uptake was shown from 40 min postinjection. However, there was low level of radioactivity uptake in tumor. [F-18]1 was not metabolized by mouse, rabbit, or human liver microsomes but was hydrolyzed significantly at physiological pH. The hydrolyzed product was further analyzed by LC-MS, showing a mass peak corresponding to that of 4-fluoro-N-(o-carboxybenzoyl)glutamic acid imide. This result suggests that [F-18]1 is easily hydrolyzed at physiological pH and thus may not be suitable for the in vivo studies of tumor angiogenesis at least in rodents, although it was reported that the hydrolysis product of thalidomide may be responsible for its angiogenesis activity in humans.

  7. Eukaryotic initiation factor 4F-sidestepping resistance mechanisms arising from expression heterogeneity.

    Science.gov (United States)

    Chu, Jennifer; Cajal, Santiago Ramon Y; Sonenberg, Nahum; Pelletier, Jerry

    2017-11-20

    There is enormous diversity in the genetic makeup and gene expression profiles between and within tumors. This heterogeneity leads to phenotypic variation and is a major mechanism of resistance to molecular targeted therapies. Here we describe a conceptual framework for targeting eukaryotic initiation factor (eIF) 4F in cancer-an essential complex that drives and promotes multiple Cancer Hallmarks. The unique nature of eIF4F and its druggability bypasses several of the heterogeneity issues that plague molecular targeted drugs developed for cancer therapy. Copyright © 2017 Elsevier Ltd. All rights reserved.

  8. In vitro assessment of the relationship between acoustic properties and bone mass density of the calcaneus by comparison of ultrasound parametric imaging and quantitative computed tomography.

    Science.gov (United States)

    Laugier, P; Droin, P; Laval-Jeantet, A M; Berger, G

    1997-02-01

    This in vitro study aimed to add new experimental evidence to clarify the relation between acoustic properties of bone and bone mineral density (BMD) of the human calcaneus. Parametric images of normalized broadband ultrasonic attenuation (nBUA) and ultrasound bone velocity (UBV) were compared with quantitative computed tomography (QCT) images of the calcaneus. The experimental protocol was designed to control the different potential sources of error in acoustic measurements, including the shape and thickness of the samples, intervening soft tissues and cortical bone, boundary effects, and variation in location of the regions of interest (ROIs) analyzed by ultrasound and X-ray. The present study was based on bone specimens from calcaneus removed from 15 cadavers (six male and nine female donors ranging from 69 to 89 years of age). Immersion ultrasonic measurements were performed in the through-thickness direction at normal incidence using a pair of focused broad-band 0.5-MHz transducers. QCT of the specimens was performed using standard 10-mm-thick slices with the Cann-Genant calibration standard. Identical, site-matched ROIs were selected for quantitative analysis on the three images. The pattern of acoustic parameters was similar to that of BMD with QCT. The relationships between nBUA and BMD (r2 = 0.75), between UBV and BMD (r2 = 0.88) and between nBUA and UBV (r2 = 0.84) were highly significant (p < 10(-4). From this study, it appears that ultrasound parameters as measured with current transmission techniques reflect mainly bone quantity and only reflect microarchitecture to a small extent and that BUA and UBV reflect the same bone property.

  9. Imaging and quantitative data acquisition of biological cell walls with Atomic Force Microscopy and Scanning Acoustic Microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Tittmann, B. R. [Penn State; Xi, X. [Penn State

    2014-09-01

    This chapter demonstrates the feasibility of Atomic Force Microscopy (AFM) and High Frequency Scanning Acoustic Microscopy (HF-SAM) as tools to characterize biological tissues. Both the AFM and the SAM have shown to provide imaging (with different resolution) and quantitative elasticity measuring abilities. Plant cell walls with minimal disturbance and under conditions of their native state have been examined with these two kinds of microscopy. After descriptions of both the SAM and AFM, their special features and the typical sample preparation is discussed. The sample preparation is focused here on epidermal peels of onion scales and celery epidermis cells which were sectioned for the AFM to visualize the inner surface (closest to the plasma membrane) of the outer epidermal wall. The nm-wide cellulose microfibrils orientation and multilayer structure were clearly observed. The microfibril orientation and alignment tend to be more organized in older scales compared with younger scales. The onion epidermis cell wall was also used as a test analog to study cell wall elasticity by the AFM nanoindentation and the SAM V(z) feature. The novelty in this work was to demonstrate the capability of these two techniques to analyze isolated, single layered plant cell walls in their natural state. AFM nanoindentation was also used to probe the effects of Ethylenediaminetetraacetic acid (EDTA), and calcium ion treatment to modify pectin networks in cell walls. The results suggest a significant modulus increase in the calcium ion treatment and a slight decrease in EDTA treatment. To complement the AFM measurements, the HF-SAM was used to obtain the V(z) signatures of the onion epidermis. These measurements were focused on documenting the effect of pectinase enzyme treatment. The results indicate a significant change in the V(z) signature curves with time into the enzyme treatment. Thus AFM and HF-SAM open the door to a systematic nondestructive structure and mechanical property

  10. Substituting mouse transcription factor Pou4f2 with a sea urchin orthologue restores retinal ganglion cell development.

    Science.gov (United States)

    Mao, Chai-An; Agca, Cavit; Mocko-Strand, Julie A; Wang, Jing; Ullrich-Lüter, Esther; Pan, Ping; Wang, Steven W; Arnone, Maria Ina; Frishman, Laura J; Klein, William H

    2016-03-16

    Pou domain transcription factor Pou4f2 is essential for the development of retinal ganglion cells (RGCs) in the vertebrate retina. A distant orthologue of Pou4f2 exists in the genome of the sea urchin (class Echinoidea) Strongylocentrotus purpuratus (SpPou4f1/2), yet the photosensory structure of sea urchins is strikingly different from that of the mammalian retina. Sea urchins have no obvious eyes, but have photoreceptors clustered around their tube feet disc. The mechanisms that are associated with the development and function of photoreception in sea urchins are largely unexplored. As an initial approach to better understand the sea urchin photosensory structure and relate it to the mammalian retina, we asked whether SpPou4f1/2 could support RGC development in the absence of Pou4f2. To answer this question, we replaced genomic Pou4f2 with an SpPou4f1/2 cDNA. In Pou4f2-null mice, retinas expressing SpPou4f1/2 were outwardly identical to those of wild-type mice. SpPou4f1/2 retinas exhibited dark-adapted electroretinogram scotopic threshold responses, indicating functionally active RGCs. During retinal development, SpPou4f1/2 activated RGC-specific genes and in S. purpuratus, SpPou4f2 was expressed in photoreceptor cells of tube feet in a pattern distinct from Opsin4 and Pax6. Our results suggest that SpPou4f1/2 and Pou4f2 share conserved components of a gene network for photosensory development and they maintain their conserved intrinsic functions despite vast morphological differences in mouse and sea urchin photosensory structures. © 2016 The Authors.

  11. SUM-RULES FOR MAGNETIC DICHROISM IN RARE-EARTH 4F-PHOTOEMISSION

    NARCIS (Netherlands)

    THOLE, BT; VANDERLAAN, G

    1993-01-01

    We present new sum rules for magnetic dichroism in spin polarized photoemission from partly filled shells which give the expectation values of the orbital and spin magnetic moments and their correlations in the ground state. We apply this to the 4f photoemission of rare earths, where the

  12. LI and LIII x-ray absorption in dysprosium and location of 4f levels

    Science.gov (United States)

    Agarwal, B. K.; Balakrishnan, V.

    1983-09-01

    The LI x-ray absorption-edge and near-edge structure in dysprosium are reported along with the first measurement of LI extended x-ray-absorption fine structure in metal and compounds. The location of 4f levels is discussed on the basis of the observed near-edge structure in the Dy LIII edge.

  13. 77 FR 64836 - Notice of Availability of Draft Environmental Impact Statement (DEIS), Draft Section 4(f...

    Science.gov (United States)

    2012-10-23

    ...), Draft Section 4(f) Evaluation, Notice of ANILCA Title XI evaluation, and Notice of Public Comment Period... and public hearing. ] SUMMARY: In accordance with the National Environmental Policy Act of 1969 (NEPA... prepared and is available for public review and comment. Included in the DEIS is a draft evaluation...

  14. Fluoride Bridges as Structure-Directing Motifs in 3d-4f Cluster Chemistry

    DEFF Research Database (Denmark)

    Birk, Torben; Pedersen, Kasper; Thuesen, Christian Aa.

    2012-01-01

    The use of kinetically robust chromium(III) fluorido complexes as synthons for mixed 3d-4f clusters is reported. The tendency toward linear {CrIII–F–LnIII} units dictates the cluster topology. Specifically, we show that reaction of cis-[CrIIIF2(NN)2]NO3 (NN = 1,10-phenanthroline (“phen”) or 2,2′-...

  15. Uterine artery embolisation for uterine fibroids using a 4F Rosch inferior mesenteric catheter

    Energy Technology Data Exchange (ETDEWEB)

    Ho, Simon S.M. [Chinese University of Hong Kong, Department of Diagnostic Radiology and Organ Imaging, Hong Kong (China); Cowan, Nigel C. [Churchill Hospital, Department of Radiology, Oxford (United Kingdom)

    2005-06-01

    Purpose:To evaluate in a prospective study the use of a 4F Rosch inferior mesenteric (RIM) catheter for uterine artery embolisation (UAE). UAE was performed in 72 women over a 37-month period. A 4F RIM braided J-curve 65-cm catheter was used in combination with an angled hydrophilic 150 cm, 0.035'' flexible tip guide-wire to catheterise the horizontal portion of both uterine arteries (UA) from a right common femoral artery (CFA) approach. Technical success was defined as successful catheterisation and embolisation of both uterine arteries. Fluoroscopic and procedure times were recorded. Mean subject age=43.7 years (range=25-57 years). Technical success was 98.6% (n=71/72). A single approach via the right CFA was used in 88.9% (n=64/72) and a bilateral CFA approach in 11.1% (n=8/72). Bilateral uterine artery catheterisation using a single 4F RIM catheter via the right CFA approach was successful in 79.2% (n=57/72). Microcatheters were used in 2.8% of patients (n=2/72). Mean fluoroscopic time=13.6{+-}5.3 min (mean{+-}SD). Mean procedure time=44.2{+-}16.5 min. High technical success rate for UAE is possible using a single 4F RIM catheter via a unilateral right CFA approach, which obviates the need for Waltman loop formation, reversed curve catheters and complex suture-catheter arrangements. (orig.)

  16. Electron swarm parameter measurements of perfluorobut-2-ene (2-C4F8)

    OpenAIRE

    Chachereau, Alise; Franck, Christian M.

    2015-01-01

    In this contribution, the electron swarm parameters of perfluorobut-2-ene (2-C4F8) mixtures with the buffer gases N2, CO2 and Argon are experimentally investigated. The effective ionization rate constant and electron drift velocity are measured in the entire E/N range up to the critical density-reduced electric field.

  17. Surface shift of the occupied and unoccupied 4f levels of the rare-earth metals

    DEFF Research Database (Denmark)

    Aldén, Magnus; Johansson, Börje; Skriver, Hans Lomholt

    1995-01-01

    The surface energy shifts of the occupied and unoccupied 4f levels for the lanthanide metals have been calculated from first principles by means of a Green’s-function technique within the tight-binding linear muffin-tin orbitals method. We use the concept of complete screening to identify the occ...

  18. The strong correlation of the 4f electrons of erbium in silicon

    CERN Document Server

    Fu Yu Rui; Wang Xun; Ye Lin

    2003-01-01

    The local spin density approximation (LSDA) with the Hubbard model correction is adopted to describe the electronic structures of O-codoped Er-Si systems. The electrons in the 4f orbitals of Er atoms are taken as localized electrons in the framework of an all-electron treatment. The total density of states (DOS) and the partial densities of states for Si(3s, 3p), Er(4f), Er(5d), Er(6s), O(2s), and O(2p) in this ErSiO system are calculated. It is found that the inclusion of the Hubbard U greatly influences the partial DOS of the Er 4f electrons. The separation between the spin-up and the spin-down states of the highly localized 4f orbitals is larger than that of the LSDA results obtained without considering the Hubbard U-parameter. The calculation results provide possible explanations of the experimentally observed erbium-induced impurity energy levels in Si detected by deep-level transient spectroscopy.

  19. Low temperature synthesis, structure and magnetic properties of Mn2[VO4]F

    Directory of Open Access Journals (Sweden)

    Daisuke Mori

    2017-12-01

    Full Text Available The compound Mn2[VO4]F was synthesized using a hydrothermal synthesis route at low temperature and its crystal structure was determined from single crystal X-ray diffraction data. Mn2[VO4]F was characterized by magnetic susceptibility and specific heat capacity measurements. Mn2[VO4]F crystallizes with the triplite-type structure, space group C2/c, a = 13.451(3 Å, b = 6.6953(16 Å, c = 10.126(3 Å, β = 116.587(4°, V = 815.6(3 Å3 and Z = 8. The structure consists of a 3D-framework built up of VO4 tetrahedra, and manganese (II polyhedra which form chains running along the [101] and [010] directions. The coordination of the manganese cations and the connectivity between the manganese polyhedra are not defined clearly due to the disorder of the fluoride anions which form zigzag chains along [001]. The magnetic susceptibility follows a Curie–Weiss behavior above 50 K with Θ = −88 K indicating that predominant magnetic interactions are antiferromagnetic. The specific heat capacity and magnetization measurements show that Mn2[VO4]F undergoes a three-dimensional magnetic ordering at TN = 30 K and a canted weak ferromagnetism due to mixed-anion effect.

  20. VHMPID RICH prototype using pressurized C{sub 4}F{sub 8}O radiator gas and VUV photon detector

    Energy Technology Data Exchange (ETDEWEB)

    Acconcia, T.V. [UNICAMP, University of Campinas, Campinas (Brazil); Agócs, A.G. [Wigner RCP of the HAS, Budapest (Hungary); Barile, F. [INFN Sezione di Bari and Universitá degli Studi di Bari, Dipartimento Interateneo di Fisica M. Merlin, Bari (Italy); Barnaföldi, G.G. [Wigner RCP of the HAS, Budapest (Hungary); Bellwied, R. [University of Houston, Houston (United States); Bencédi, G. [Wigner RCP of the HAS, Budapest (Hungary); Bencze, G., E-mail: Gyorgy.Bencze@cern.ch [Wigner RCP of the HAS, Budapest (Hungary); Berényi, D.; Boldizsár, L. [Wigner RCP of the HAS, Budapest (Hungary); Chattopadhyay, S. [Saha Institute, Kolkata (India); Chinellato, D.D. [University of Houston, Houston (United States); Cindolo, F. [University of Salerno, Salerno (Italy); Cossyleon, K. [Chicago State University, Chicago, IL (United States); Das, D.; Das, K.; Das-Bose, L. [Saha Institute, Kolkata (India); Dash, A.K. [UNICAMP, University of Campinas, Campinas (Brazil); D' Ambrosio, S. [University of Salerno, Salerno (Italy); De Cataldo, G. [INFN Sezione di Bari and Universitá degli Studi di Bari, Dipartimento Interateneo di Fisica M. Merlin, Bari (Italy); De Pasquale, S. [University of Salerno, Salerno (Italy); and others

    2014-12-11

    A small-size prototype of a new Ring Imaging Cherenkov (RICH) detector using for the first time pressurized C4F8O radiator gas and a photon detector consisting of MWPC equipped with a CsI photocathode has been built and tested at the PS accelerator at CERN. It contained all the functional elements of the detector proposed as Very High Momentum Particle Identification (VHMPID) upgrade for the ALICE experiment at LHC to provide charged hadron track-by-track identification in the momentum range starting from 5 potentially up to 25 GeV/c. In the paper the equipment and its elements are described and some characteristic test results are shown.

  1. Influence of Acoustic Overstimulation on the Central Auditory System: An Functional Magnetic Resonance Imaging (fMRI) Study.

    Science.gov (United States)

    Wolak, Tomasz; Cieśla, Katarzyna; Rusiniak, Mateusz; Piłka, Adam; Lewandowska, Monika; Pluta, Agnieszka; Skarżyński, Henryk; Skarżyński, Piotr H

    2016-11-28

    BACKGROUND The goal of the fMRI experiment was to explore the involvement of central auditory structures in pathomechanisms of a behaviorally manifested auditory temporary threshold shift in humans. MATERIAL AND METHODS The material included 18 healthy volunteers with normal hearing. Subjects in the exposure group were presented with 15 min of binaural acoustic overstimulation of narrowband noise (3 kHz central frequency) at 95 dB(A). The control group was not exposed to noise but instead relaxed in silence. Auditory fMRI was performed in 1 session before and 3 sessions after acoustic overstimulation and involved 3.5-4.5 kHz sweeps. RESULTS The outcomes of the study indicate a possible effect of acoustic overstimulation on central processing, with decreased brain responses to auditory stimulation up to 20 min after exposure to noise. The effect can be seen already in the primary auditory cortex. Decreased BOLD signal change can be due to increased excitation thresholds and/or increased spontaneous activity of auditory neurons throughout the auditory system. CONCLUSIONS The trial shows that fMRI can be a valuable tool in acoustic overstimulation studies but has to be used with caution and considered complimentary to audiological measures. Further methodological improvements are needed to distinguish the effects of TTS and neuronal habituation to repetitive stimulation.

  2. Latest Trends in Acoustic Sensing

    Directory of Open Access Journals (Sweden)

    Cinzia Caliendo

    2014-03-01

    Full Text Available Acoustics-based methods offer a powerful tool for sensing applications. Acoustic sensors can be applied in many fields ranging from materials characterization, structural health monitoring, acoustic imaging, defect characterization, etc., to name just a few. A proper selection of the acoustic wave frequency over a wide spectrum that extends from infrasound (<20 Hz up to ultrasound (in the GHz–band, together with a number of different propagating modes, including bulk longitudinal and shear waves, surface waves, plate modes, etc., allow acoustic tools to be successfully applied to the characterization of gaseous, solid and liquid environments. The purpose of this special issue is to provide an overview of the research trends in acoustic wave sensing through some cases that are representative of specific applications in different sensing fields.

  3. IMAGING APPARATUS AND METHOD

    NARCIS (Netherlands)

    Manohar, Srirang; van Leeuwen, A.G.J.M.

    2008-01-01

    A thermoacoustic imaging apparatus comprises an electromagnetic radiation source configured to irradiate a sample area and an acoustic signal detection probe arrangement for detecting acoustic signals. A radiation responsive acoustic signal generator is added outside the sample area. The detection

  4. Imaging Apparatus And Method

    NARCIS (Netherlands)

    Manohar, Srirang; van Leeuwen, A.G.J.M.

    2010-01-01

    A thermoacoustic imaging apparatus comprises an electromagnetic radiation source configured to irradiate a sample area and an acoustic signal detection probe arrangement for detecting acoustic signals. A radiation responsive acoustic signal generator is added outside the sample area. The detection

  5. Optimization of real-time acoustical and mechanical monitoring of high intensity focused ultrasound (HIFU) treatment using harmonic motion imaging for high focused ultrasound (HMIFU).

    Science.gov (United States)

    Hou, Gary Y; Marquet, Fabrice; Wang, Shutao; Konofagou, Elisa E

    2013-01-01

    Harmonic Motion Imaging (HMI) for Focused Ultrasound (HMIFU) is a recently developed high-intensity focused ultrasound (HIFU) treatment monitoring method with feasibilities demonstrated in silica, in vitro and in vivo. Its principle is based on emission of an Amplitude-modulated therapeutic ultrasound beam utilizing a therapeutic transducer to induce an oscillatory radiation force while tracking the focal tissue mechanical response during the HIFU treatment using a confocally-aligned diagnostic transducer. In order to translate towards the clinical implementation of HMIFU, a complete assessment study is required in order to investigate the optimal radiation force threshold for reliable monitoring the local tissue mechanical property changes, i.e., the estimation HMIFU displacement under thermal, acoustical, and mechanical effects within focal medium (i.e., boiling, cavitation, and nonlinearity) using biological specimen. In this study, HMIFU technique is applied on HIFU treatment monitoring on freshly excised ex vivo canine liver specimens. In order to perform the multi-characteristic assessment, the diagnostic transducer was operated as either a pulse-echo imager or Passive Cavitation Detector (PCD) to assess the acoustic and mechanical response, while a bare-wire thermocouple was used to monitor the focal temperature change. As the acoustic power of HIFU treatment was ranged from 2.3 to 11.4 W, robust HMI displacement was observed across the entire range. Moreover, an optimized range for high quality displacement monitoring was found to be between 3.6 to 5.2W, where displacement showed an increase followed by significant decrease, indicating a stiffening of focal medium due to thermal lesion formation, while the correlation coefficient was maintained above 0.95.

  6. Contribution of the 4f-core-excited states in determination of atomic properties in the promethium isoelectronic sequence

    Science.gov (United States)

    Safronova, U. I.; Safronova, A. S.; Beiersdorfer, P.

    2013-09-01

    The atomic properties of Pm-like ions were comprehensively studied using relativistic atomic codes. Excitation energies of the 4f14nl (with nl=5s, 6s, 5p, 6p, 5d, 6d, and 5f) states in Pm-like ions with nuclear charge Z ranging from 74 to 100 are evaluated within the framework of relativistic many-body theory (RMBPT). First- and second-order Coulomb energies and first- and second-order Breit corrections to the energies are calculated. Two alternative treatments of the Breit interaction are investigated. In the first approach we omit Breit contributions to the Dirac-Fock potential and evaluate Coulomb and Breit-Coulomb corrections through second order perturbatively. In the second approach were included both Coulomb and Breit contributions on the same footing via the Breit-Dirac-Fock potential and then treat the residual Breit and Coulomb interactions perturbatively. The results obtained from the two approaches are compared and discussed. The important question of what is the ground state in Pm-like ions was answered. Properties of the 4f-core-excited states are evaluated using the multiconfiguration relativistic Hebrew University Lawrence Livermore atomic code (hullac code) and the Hartree-Fock-relativistic method (cowan code). We evaluate excitation energies and transition rates in Pm-like ions with nuclear charge Z ranging from 74 to 92. Our large scale calculations include the following set of configurations: 4f145s, 4f145p, 4f135s2, 4f135p2, 4f135s5p, 4f125s25p, 4f125s5p2, and 4f125p3. Trends of excitation energies as function of Z are shown graphically for selected states. Excitation energies, transition rates, and lifetimes in Pm-like tungsten are evaluated with additional inclusion of the 4f115s25p2, 4f115s5p3, 4f105s25p3, and 4f105s5p4 configurations. This represents an unusual example of an atomic system where the even-parity complex [4f145s+4f135s5p+4f125s5p2+4f115s5p3+4f105s5p4] and the odd-parity complex [4f145p+4f135s2+4f125s25p+4f115s25p2+4f105s25p3

  7. Acoustic textiles

    CERN Document Server

    Nayak, Rajkishore

    2016-01-01

    This book highlights the manufacturing and applications of acoustic textiles in various industries. It also includes examples from different industries in which acoustic textiles can be used to absorb noise and help reduce the impact of noise at the workplace. Given the importance of noise reduction in the working environment in several industries, the book offers a valuable guide for companies, educators and researchers involved with acoustic materials.

  8. Is the lateral angle of the internal acoustic canal sexually dimorphic in non-adults? An investigation by routine cranial magnetic resonance imaging.

    Science.gov (United States)

    Afacan, G O; Onal, T; Akansel, G; Arslan, A S

    2017-10-01

    The lateral angle of the internal acoustic canal is one of the measurements of petrous bone that has been previously studied for sex estimation, mostly in adults. We aimed at evaluating the effects of age, side, and sex on the lateral angle of the internal acoustic canal in pediatric patients. Pediatric routine cranial MRI studies were retrospectively investigated for this study. The lateral angle was measured on T2-weighted axial images when the anterior and posterior lips of the meatus and the cochlea were clearly visible on the same image. The data were evaluated for age, side and sex-related changes. Although 552 temporal bones from 273 patients were inspected, due to exclusion criteria lateral angle could be satisfactorily measured only in 101 temporal bones from 58 patients. The measurements did not differ significantly between sexes. An age-related, statistically significant decrease was observed for the entire pediatric sample studied, as well as for the males, but not for females. The measurements did not differ from side to side. The significant age-related decrease in lateral angle in male pediatric patients that was not detected in female counterparts may be the reflection of a sex-related difference in temporal bone development during childhood. Routine cranial MRI data may help investigators study age and sex-related changes in lateral angle in children. Copyright © 2017 Elsevier GmbH. All rights reserved.

  9. Ion Acoustic Microscopy

    Science.gov (United States)

    1985-07-01

    Murphy and L. C. Aamodt , "Signal Enhancement in Photothermal Imaging Produced by Three Dimensional Heat Flow", Appl. Phys. Lett. 39, 519 (1981); L. C... Aamodt and J. C. Murphy, "Photothermal Measurements Using a Localized Excitation Source", J. Appl. Phys. 52, 4903 (1981) (9) R. L. Thomas, L. D. Favro...25 (23) J. C. Murphy, F. G. Satkiewicz and L. C. Aamodt , "Ion Acoustic Imaging of Buried Flaws in Aluminum", Review of Progress in Quantitative NDE

  10. A rail system for circular synthetic aperture sonar imaging and acoustic target strength measurements: design/operation/preliminary results.

    Science.gov (United States)

    Kennedy, J L; Marston, T M; Lee, K; Lopes, J L; Lim, R

    2014-01-01

    A 22 m diameter circular rail, outfitted with a mobile sonar tower trolley, was designed, fabricated, instrumented with underwater acoustic transducers, and assembled on a 1.5 m thick sand layer at the bottom of a large freshwater pool to carry out sonar design and target scattering response studies. The mobile sonar tower translates along the rail via a drive motor controlled by customized LabVIEW software. The rail system is modular and assembly consists of separately deploying eight circular arc sections, measuring a nominal center radius of 11 m and 8.64 m arc length each, and having divers connect them together in the underwater environment. The system enables full scale measurements on targets of interest with 0.1° angular resolution over a complete 360° aperture, without disrupting target setup, and affording a level of control over target environment conditions and noise sources unachievable in standard field measurements. In recent use, the mobile cart carrying an instrumented sonar tower was translated along the rail in 720 equal position increments and acoustic backscatter data were acquired at each position. In addition, this system can accommodate both broadband monostatic and bistatic scattering measurements on targets of interest, allowing capture of target signature phenomena under diverse configurations to address current scientific and technical issues encountered in mine countermeasure and unexploded ordnance applications. In the work discussed here, the circular rail apparatus is used for acoustic backscatter testing, but this system also has the capacity to facilitate the acquisition of magnetic and optical sensor data from targets of interest. A brief description of the system design and operation will be presented along with preliminary processed results for data acquired from acoustic measurements conducted at the Naval Surface Warfare Center, Panama City Division Test Pond Facility. [Work Supported by the U.S. Office of Naval Research and

  11. Musical Acoustics

    Science.gov (United States)

    Gough, Colin

    This chapter provides an introduction to the physical and psycho-acoustic principles underlying the production and perception of the sounds of musical instruments. The first section introduces generic aspects of musical acoustics and the perception of musical sounds, followed by separate sections on string, wind and percussion instruments.

  12. Long-lived transient anion of c-C4F8O

    Science.gov (United States)

    Kočišek, J.; Janečková, R.; Fedor, J.

    2018-02-01

    We report partial cross sections for electron attachment to c-C4F8O, a gas with promising technological applications in free-electron-rich environments. The dissociative electron attachment leads to a number of anionic fragments resulting from complex bond-breaking and bond-forming processes. However, the anion with the highest abundance is the non-dissociated (transient) parent anion which is formed around 0.9 eV electron energy. Its lifetime reaches tens of microseconds. We discuss the origin of this long lifetime, the anion's strong interactions with other molecules, and the consequences for electron-scavenging properties of c-C4F8O in denser environments, in particular for its use in mixtures with CO2 and N2.

  13. Synthetic and Computational Approach on novel Transitional metal and 3d-4f Molecular Magnetic Materials

    OpenAIRE

    Radhakrishnan, Vignesh Kuduva

    2017-01-01

    This thesis deals with the design, synthesis, structures and modeling of spin-Hamiltonian parameters (such as J, D and g–tensors) in manganese complexes and mixed transition metal-lanthanide (3d-4f) based complexes using both experimental and computational tools. Certain mononuclear/polynuclear complexes are capable of retaining their magnetization even in the absence of magnetic field which gives rise to magnetic hysteresis at a molecular level and an ability to act as m...

  14. The structure of NH4F as determined by neutron and X-ray diffraction

    NARCIS (Netherlands)

    Adrian, H.W.W.; Feil, D.

    1969-01-01

    Neutron and X-ray intensities of NH4F were measured at -196°C and -155°C respectively. The wurtzite type structure and space group P63mc were confirmed. The displacement of the two h.c.p. sublattices, formed by each of the F-- and NH+4- ions, is such that all bond-distances are equivalent. The N-H

  15. Onderzoek naar de toepasbaarheid van Flow Field Flow Fractionation (4F) voor biopolymeeranalyse

    OpenAIRE

    Goewie; C.E.

    1986-01-01

    Flow Field Flow Fractionation (4F), een veelbelovende experimentele scheidingstechniek voor (bio)polymeren met massas 10-3-10-6, werd aan de Universiteit van Utah uitgetest op bruikbaarheid voor het RIVM. Met deze techniek zijn de globale molmassaverdelingen bepaald van een aantal humusmonsters en grondwaterextracten waarvoor bij derden (LAC en KIWA) belangstelling bestond. De techniek is in principe goed bruikbaar, theoretisch onderbouwd en eenvoudig te hanteren. Constructie van de apparatuu...

  16. Communication Acoustics

    DEFF Research Database (Denmark)

    Blauert, Jens

    Communication Acoustics deals with the fundamentals of those areas of acoustics which are related to modern communication technologies. Due to the advent of digital signal processing and recording in acoustics, these areas have enjoyed an enormous upswing during the last 4 decades. The book...... chapters represent review articles covering the most relevant areas of the field. They are written with the goal of providing students with comprehensive introductions. Further they offer a supply of numerous references to the relevant literature. Besides its usefulness as a textbook, this will make...... the book a source of valuable information for those who want to improve or refresh their knowledge in the field of communication acoustics - and to work their way deeper into it. Due to its interdisciplinary character Communication Acoustics is bound to attract readers from many different areas, such as...

  17. The Transcription Factor E4F1 Coordinates CHK1-Dependent Checkpoint and Mitochondrial Functions

    Directory of Open Access Journals (Sweden)

    Geneviève Rodier

    2015-04-01

    Full Text Available Recent data support the notion that a group of key transcriptional regulators involved in tumorigenesis, including MYC, p53, E2F1, and BMI1, share an intriguing capacity to simultaneously regulate metabolism and cell cycle. Here, we show that another factor, the multifunctional protein E4F1, directly controls genes involved in mitochondria functions and cell-cycle checkpoints, including Chek1, a major component of the DNA damage response. Coordination of these cellular functions by E4F1 appears essential for the survival of p53-deficient transformed cells. Acute inactivation of E4F1 in these cells results in CHK1-dependent checkpoint deficiency and multiple mitochondrial dysfunctions that lead to increased ROS production, energy stress, and inhibition of de novo pyrimidine synthesis. This deadly cocktail leads to the accumulation of uncompensated oxidative damage to proteins and extensive DNA damage, ending in cell death. This supports the rationale of therapeutic strategies simultaneously targeting mitochondria and CHK1 for selective killing of p53-deficient cancer cells.

  18. Pb 4f photoelectron spectroscopy on mass-selected anionic lead clusters at FLASH

    Science.gov (United States)

    Bahn, J.; Oelßner, P.; Köther, M.; Braun, C.; Senz, V.; Palutke, S.; Martins, M.; Rühl, E.; Ganteför, G.; Möller, T.; von Issendorff, B.; Bauer, D.; Tiggesbäumker, J.; Meiwes-Broer, K.-H.

    2012-07-01

    4f core level photoelectron spectroscopy has been performed on negatively charged lead clusters, in the size range of 10-90 atoms. We deploy 4.7 nm radiation from the free-electron laser FLASH, yielding sufficiently high photon flux to investigate mass-selected systems in a beam. A new photoelectron detection system based on a hemispherical spectrometer and a time-resolving delayline detector makes it possible to assign electron signals to each micro-pulse of FLASH. The resulting 4f binding energies show good agreement with the metallic sphere model, giving evidence for a fast screening of the 4f core holes. By comparing the present work with previous 5d and valence region data, the paper presents a comprehensive overview of the energetics of lead clusters, from atoms to bulk. Special care is taken to discuss the differences of the valence- and core-level anion cluster photoionizations. Whereas in the valence case the escaping photoelectron interacts with a neutral system near its ground state, core-level ionization leads to transiently highly excited neutral clusters. Thus, the photoelectron signal might carry information on the relaxation dynamics.

  19. Radiation-force-based estimation of acoustic attenuation using harmonic motion imaging (HMI) in phantoms and in vitro livers before and after HIFU ablation.

    Science.gov (United States)

    Chen, Jiangang; Hou, Gary Y; Marquet, Fabrice; Han, Yang; Camarena, Francisco; Konofagou, Elisa

    2015-10-07

    Acoustic attenuation represents the energy loss of the propagating wave through biological tissues and plays a significant role in both therapeutic and diagnostic ultrasound applications. Estimation of acoustic attenuation remains challenging but critical for tissue characterization. In this study, an attenuation estimation approach was developed using the radiation-force-based method of harmonic motion imaging (HMI). 2D tissue displacement maps were acquired by moving the transducer in a raster-scan format. A linear regression model was applied on the logarithm of the HMI displacements at different depths in order to estimate the acoustic attenuation. Commercially available phantoms with known attenuations (n = 5) and in vitro canine livers (n = 3) were tested, as well as HIFU lesions in in vitro canine livers (n = 5). Results demonstrated that attenuations obtained from the phantoms showed a good correlation (R² = 0.976) with the independently obtained values reported by the manufacturer with an estimation error (compared to the values independently measured) varying within the range of 15-35%. The estimated attenuation in the in vitro canine livers was equal to 0.32   ±   0.03 dB cm(-1) MHz(-1), which is in good agreement with the existing literature. The attenuation in HIFU lesions was found to be higher (0.58   ±   0.06 dB cm(-1) MHz(-1)) than that in normal tissues, also in agreement with the results from previous publications. Future potential applications of the proposed method include estimation of attenuation in pathological tissues before and after thermal ablation.

  20. Radiation-force-based estimation of acoustic attenuation using harmonic motion imaging (HMI) in phantoms and in vitro livers before and after HIFU ablation

    Science.gov (United States)

    Chen, Jiangang; Hou, Gary Y.; Marquet, Fabrice; Han, Yang; Camarena, Francisco; Konofagou, Elisa

    2015-10-01

    Acoustic attenuation represents the energy loss of the propagating wave through biological tissues and plays a significant role in both therapeutic and diagnostic ultrasound applications. Estimation of acoustic attenuation remains challenging but critical for tissue characterization. In this study, an attenuation estimation approach was developed using the radiation-force-based method of harmonic motion imaging (HMI). 2D tissue displacement maps were acquired by moving the transducer in a raster-scan format. A linear regression model was applied on the logarithm of the HMI displacements at different depths in order to estimate the acoustic attenuation. Commercially available phantoms with known attenuations (n=5 ) and in vitro canine livers (n=3 ) were tested, as well as HIFU lesions in in vitro canine livers (n=5 ). Results demonstrated that attenuations obtained from the phantoms showed a good correlation ({{R}2}=0.976 ) with the independently obtained values reported by the manufacturer with an estimation error (compared to the values independently measured) varying within the range of 15-35%. The estimated attenuation in the in vitro canine livers was equal to 0.32   ±   0.03 dB cm-1 MHz-1, which is in good agreement with the existing literature. The attenuation in HIFU lesions was found to be higher (0.58   ±   0.06 dB cm-1 MHz-1) than that in normal tissues, also in agreement with the results from previous publications. Future potential applications of the proposed method include estimation of attenuation in pathological tissues before and after thermal ablation.

  1. High-Frequency Underwater Acoustic Propagation in a Port Modeled as a Three-Dimensional Duct Closed at One End Using the Method of Images

    Directory of Open Access Journals (Sweden)

    Pierre-Philippe J. Beaujean

    2012-01-01

    Full Text Available A computer-efficient model for underwater acoustic propagation in a shallow, three-dimensional rectangular duct closed at one end has been developed using the method of images. The duct simulates a turning basin located in a port, surrounded with concrete walls, and filled with sea water. The channel bottom is composed of silt. The modeled impulse response is compared with the impulse response measured between 15 kHz and 33 kHz. Despite small sensor-position inaccuracies and an approximated duct geometry, the impulse response can be modeled with a relative echo magnitude error of 1.62 dB at worst and a relative echo location error varying between 0% and 4% when averaged across multiple measurements and sensor locations. This is a sufficient level of accuracy for the simulation of an acoustic communication system operating in the same frequency band and in shallow waters, as time fluctuations in echo magnitude commonly reach 10 dB in this type of environment.

  2. Acoustics Research

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Fisheries acoustics data are collected from more than 200 sea-days each year aboard the FRV DELAWARE II and FRV ALBATROSS IV (decommissioned) and the FSV Henry B....

  3. Room Acoustics

    Science.gov (United States)

    Kuttruff, Heinrich; Mommertz, Eckard

    The traditional task of room acoustics is to create or formulate conditions which ensure the best possible propagation of sound in a room from a sound source to a listener. Thus, objects of room acoustics are in particular assembly halls of all kinds, such as auditoria and lecture halls, conference rooms, theaters, concert halls or churches. Already at this point, it has to be pointed out that these conditions essentially depend on the question if speech or music should be transmitted; in the first case, the criterion for transmission quality is good speech intelligibility, in the other case, however, the success of room-acoustical efforts depends on other factors that cannot be quantified that easily, not least it also depends on the hearing habits of the listeners. In any case, absolutely "good acoustics" of a room do not exist.

  4. Acoustic Neuroma

    Science.gov (United States)

    ... in June 1969 at Karolinska Hospital in Stockholm, Sweden. Since then, more than 10,000 acoustic neuroma ... of neurosurgeons, radiation oncologists, medical physicists and a nursing staff. Specialists in neuroimaging join the team when ...

  5. Battlefield acoustics

    CERN Document Server

    Damarla, Thyagaraju

    2015-01-01

    This book presents all aspects of situational awareness in a battlefield using acoustic signals. It starts by presenting the science behind understanding and interpretation of sound signals. The book then goes on to provide various signal processing techniques used in acoustics to find the direction of sound source, localize gunfire, track vehicles, and detect people. The necessary mathematical background and various classification and fusion techniques are presented. The book contains majority of the things one would need to process acoustic signals for all aspects of situational awareness in one location. The book also presents array theory, which is pivotal in finding the direction of arrival of acoustic signals. In addition, the book presents techniques to fuse the information from multiple homogeneous/heterogeneous sensors for better detection. MATLAB code is provided for majority of the real application, which is a valuable resource in not only understanding the theory but readers, can also use the code...

  6. A Study of the Reaction Between Quinone and 2R4F Cigarette Smoke Condensate

    Directory of Open Access Journals (Sweden)

    Coleman WM

    2014-12-01

    Full Text Available A study using atomic emission detection (AED as an approach to explore the fate of quinone added into 2R4F cigarette smoke condensate (CSC have been performed. Both natural isotope quinone and 13C labeled quinone were used in the study. When coupled with a gas chromatographic separation (GC/AED, the AED provided informative new data on 13C isotope enriched products generated following reactions between 2R4F CSC and the quinone. Two 13C containing species were detected by GC/AED. Matching chromatographic separation using gas chromatography/mass selective detection (GC/MSD allowed for a structural assignment of a relatively minor CSC 13C 6quinone reaction product as nitrohydroquinone (13C6NO2HQ. The chemical mechanism accounting for the formation of 13C6NO2HQ in the CSC was envisioned to be a reaction product between HONO and 13C 6Quinone (13C6Q to form 13C6NO2Q, followed by reduction of 13C6NO2Q to 13C6NO2HQ. The amount of 13C6NO2HQ accounted for ~6% of the added 13C6Q. Identical trends in reaction chemistries were found for experiments with 12C6Q. The major reaction product detected upon addition of 13C6Q to the 2R4F CSC sample was 13C6HQ. 13C6HQ accounted for, on average, ~47% of the initial 13C6Q concentration. Identical trends in reaction chemistries were found for experiments with 12C6Q. No additional 13C containing species were detected. A 13C AED compound independent calibration (CIC approach under the operating conditions was not possible. This work further expands the knowledge regarding possible reactions of quinone and hydroquinone in CSC.

  7. Red nucleus and rubrospinal tract disorganization in the absence of Pou4f1

    Directory of Open Access Journals (Sweden)

    Jesus E. eMartinez-Lopez

    2015-02-01

    Full Text Available The red nucleus is a neuronal population that plays an important role in forelimb motor control and locomotion. Histologically it is subdivided into two subpopulations, the parvocellular red nucleus located in the diencephalon and the magnocellular red nucleus in the mesencephalon. The red nucleus integrates signals from motor cortex and cerebellum and projects to spinal cord interneurons and motor neurons through the rubrospinal tract. Pou4f1 is a transcription factor highly expressed in this nucleus that has been related to its specification. Here we profoundly analyzed consequences of Pou4f1 loss-of-function in development, maturation and axonal projection of the red nucleus. Surprisingly, red nucleus neurons are specified and maintained in the mutant, no cell death was detected. Nevertheless, the nucleus appeared disorganized with a strong delay in radial migration and with a wider neuronal distribution; the neurons did not form a compacted population as they do in controls, Robo1 and Slit2 were miss-expressed. Cplx1 and Npas1, expressed in the red nucleus, are transcription factors involved in neurotransmitter release, neuronal maturation and motor function processes among others. In our mutant mice, both transcription factors are lost, suggesting an abnormal maturation of the red nucleus. The resulting altered nucleus occupied a wider territory. Finally, we examined rubrospinal tract development and found that the red nucleus neurons were able to project to the spinal cord but their axons appeared defasciculated. These data suggest that Pou4f1 is necessary for the maturation of red nucleus neurons but not for their specification and maintenance.

  8. Red nucleus and rubrospinal tract disorganization in the absence of Pou4f1

    Science.gov (United States)

    Martinez-Lopez, Jesus E.; Moreno-Bravo, Juan A.; Madrigal, M. Pilar; Martinez, Salvador; Puelles, Eduardo

    2015-01-01

    The red nucleus (RN) is a neuronal population that plays an important role in forelimb motor control and locomotion. Histologically it is subdivided into two subpopulations, the parvocellular RN (pRN) located in the diencephalon and the magnocellular RN (mRN) in the mesencephalon. The RN integrates signals from motor cortex and cerebellum and projects to spinal cord interneurons and motor neurons through the rubrospinal tract (RST). Pou4f1 is a transcription factor highly expressed in this nucleus that has been related to its specification. Here we profoundly analyzed consequences of Pou4f1 loss-of-function in development, maturation and axonal projection of the RN. Surprisingly, RN neurons are specified and maintained in the mutant, no cell death was detected. Nevertheless, the nucleus appeared disorganized with a strong delay in radial migration and with a wider neuronal distribution; the neurons did not form a compacted population as they do in controls, Robo1 and Slit2 were miss-expressed. Cplx1 and Npas1, expressed in the RN, are transcription factors involved in neurotransmitter release, neuronal maturation and motor function processes among others. In our mutant mice, both transcription factors are lost, suggesting an abnormal maturation of the RN. The resulting altered nucleus occupied a wider territory. Finally, we examined RST development and found that the RN neurons were able to project to the spinal cord but their axons appeared defasciculated. These data suggest that Pou4f1 is necessary for the maturation of RN neurons but not for their specification and maintenance. PMID:25698939

  9. System and method to create three-dimensional images of non-linear acoustic properties in a region remote from a borehole

    Science.gov (United States)

    Vu, Cung; Nihei, Kurt T.; Schmitt, Denis P.; Skelt, Christopher; Johnson, Paul A.; Guyer, Robert; TenCate, James A.; Le Bas, Pierre-Yves

    2013-01-01

    In some aspects of the disclosure, a method for creating three-dimensional images of non-linear properties and the compressional to shear velocity ratio in a region remote from a borehole using a conveyed logging tool is disclosed. In some aspects, the method includes arranging a first source in the borehole and generating a steered beam of elastic energy at a first frequency; arranging a second source in the borehole and generating a steerable beam of elastic energy at a second frequency, such that the steerable beam at the first frequency and the steerable beam at the second frequency intercept at a location away from the borehole; receiving at the borehole by a sensor a third elastic wave, created by a three wave mixing process, with a frequency equal to a difference between the first and second frequencies and a direction of propagation towards the borehole; determining a location of a three wave mixing region based on the arrangement of the first and second sources and on properties of the third wave signal; and creating three-dimensional images of the non-linear properties using data recorded by repeating the generating, receiving and determining at a plurality of azimuths, inclinations and longitudinal locations within the borehole. The method is additionally used to generate three dimensional images of the ratio of compressional to shear acoustic velocity of the same volume surrounding the borehole.

  10. Inspection of copper canisters for spent nuclear fuel by means of ultrasound. NDE of friction stir welds, nonlinear acoustics, ultrasonic imaging

    Energy Technology Data Exchange (ETDEWEB)

    Stepinski, Tadeusz (ed.); Lingvall, Fredrik; Wennerstroem, Erik; Ping Wu [Uppsala Univ., Dept. of Materials Science (Sweden). Signals and Systems

    2004-01-01

    This report contains results concerning advanced ultrasound for the inspection of copper canisters for spent nuclear fuel obtained at Signals and Systems, Uppsala University in years 2002/2003. After a short introduction a review of the NDE techniques that have been applied to the assessment of friction stir welds (FSW) is presented. The review is based on the results reported by the specialists from the USA, mostly from the aerospace industry. A separate chapter is devoted to the extended experimental and theoretical research concerning potential of nonlinear waves in NDE applications. Further studies concerning nonlinear propagation of acoustic and elastic waves (classical nonlinearity) are reported. Also a preliminary investigation of the nonlinear ultrasonic detection of contacts and interfaces (non-classical nonlinearity) is included. Report on the continuation of previous work concerning computer simulation of nonlinear propagations of ultrasonic beams in water and in immersed solids is also presented. Finally, results of an investigation concerning a new method of synthetic aperture imaging (SAI) and its comparison to the traditional phased array (PA) imaging and to the synthetic aperture focusing technique (SAFT) are presented. A new spatial-temporal filtering method is presented that is a generalization of the previously proposed filter. Spatial resolution of the proposed method is investigated and compared experimentally to that of classical SAFT and PA imaging. Performance of the proposed method for flat targets is also investigated.

  11. Investigation of contact acoustic nonlinearity in delaminations by shearographic imaging, laser doppler vibrometric scanning and finite difference modeling.

    Science.gov (United States)

    Sarens, Bart; Verstraeten, Bert; Glorieux, Christ; Kalogiannakis, Georgios; Van Hemelrijck, Danny

    2010-06-01

    Full-field dynamic shearography and laser Doppler vibrometric scanning are used to investigate the local contact acoustic nonlinear generation of delamination-induced effects on the vibration of a harmonically excited composite plate containing an artificial defect. Nonlinear elastic behavior caused by the stress-dependent boundary conditions at the delamination interfaces of a circular defect is also simulated by a 3-D second-order, finite-difference, staggered-grid model (displacement-stress formulation). Both the experimental and simulated data reveal an asymmetric motion of the layer above the delamination, which acts as a membrane vibrating with enhanced displacement amplitude around a finite offset displacement. The spectrum of the membrane motion is enriched with clapping-induced harmonics of the excitation frequency. In case of a sufficiently thin and soft membrane, the simulations reveal clear modal behavior at sub-harmonic frequencies caused by inelastic clapping.

  12. Seismo-acoustic imaging of marine hard substrate habitats: a case study from the German Bight (SE North Sea)

    Science.gov (United States)

    Papenmeier, Svenja; Hass, H. Christian

    2016-04-01

    The detection of hard substrate habitats in sublittoral environments is a considerable challenge in spite of modern high resolution hydroacoustic techniques. In offshore areas those habitats are mainly represented by either cobbles and boulders (stones) often located in wide areas of soft sediments or by glacial relict sediments (heterogeneous mixture of medium sand to gravel size with cobbles and boulders). Sediment classification and object detection is commonly done on the basis of hydroacoustic backscatter intensities recorded with e.g. sidescan sonar (SSS) and multibeam echo sounder (MBES). Single objects lying on the sediment such as stones can generally be recognized by the acoustic shadow behind the object. However, objects close to the sonar's nadir may remain undetected because their shadows are below the data resolution. Further limitation in the detection of objects is caused by sessile communities that thrive on the objects. The bio-cover tends to absorb most of the acoustic signal. Automated identification based on the backscatter signal is often not satisfactory, especially when stones are present in a setting with glacial deposits. Areas characterized by glacial relict sediments are hardly differentiable in their backscatter characteristics from rippled coarse sand and fine gravel (rippled coarse sediments) without an intensive ground-truthing program. From the ecological point of view the relict and rippled coarse sediments are completely different habitats and need to be distinguished. The case study represents a seismo-acoustic approach in which SSS and nonlinear sediment echo sounder (SES) data are combined to enable a reliable and reproducible differentiation between relict sediments (with stones and coarse gravels) and rippled coarse sediments. Elevated objects produce hyperbola signatures at the sediment surface in the echo data which can be used to complement the SSS data. The nonlinear acoustic propagation of the SES sound pulses produces a

  13. Electron attachment, ionization and drift in c-C4F8

    Science.gov (United States)

    de Urquijo, J.; Basurto, E.

    2001-05-01

    The pulsed Townsend method has been used to measure the drift velocity ve and the density-normalized effective ionization coefficient (α-η)/N, (α and η are the ionization and attachment coefficients, respectively) in c-C4F8 over the density-normalized electric field strength E/N, 12 Td≤E/N≤43 Td and 330 Td≤E/N≤600 Td (1 Td = 10-17 V cm2), at pressures between 1 and 7.5 Torr (1 Torr = 133.3 Pa). For 12 Td≤E/N≤43 Td, the above parameters were found to be pressure independent, while for the range 330 Td≤E/N≤600 Td an inverse dependence of the above coefficients was found for gas pressures less than 2 Torr. Such dependence is believed to be due to the autodetachment of the originally formed, unstable parent negative ion c-C4F8-*. At low E/N, no previous data for ve or (α-η)/N were found for comparison with the present data. A critical field strength of E/Ncrit = 439.5 Td, for which α = η, was found to be in good agreement with previous data.

  14. Hexameric polyoxometalates decorated by six 3d-4f heterometallic clusters.

    Science.gov (United States)

    Zhang, Zhi-Ming; Li, Yang-Guang; Yao, Shuang; Wang, En-Bo

    2011-06-28

    Two nanosized hexameric polyoxometalate-based solid state assemblies (H(2)en)(6)Na(15)K(9)[Dy(6)Fe(6)(H(2)O)(12)(SiW(10)O(38))(6)]·34H(2)O (1) and K(13)Na(17)[H(2)en](3)[Tb(6)Fe(6)(H(2)O)(12)(SiW(10)O(38))(6)]·40H(2)O (2) (en = 1,2-ethylenediamine), decorated by six [Ln-(μ(3)-O)(3)-Fe] 3d-4f heterometallic clusters, have been synthesized by the hydrothermal method, and characterized by IR, element analysis, magnetic studies and the single-crystal X-ray analyses. The detailed study of the synthetic conditions reveals that the use of the organic ligands, pH value and the reaction temperature all play important roles in the synthesis of the 3d-4f heterometallic POMs. Magnetic study suggests the presence of antiferromagnetic interactions in these two compounds. This journal is © The Royal Society of Chemistry 2011

  15. Charge transport through a 4f spin state in a single molecule magnet

    Science.gov (United States)

    Hirjibehedin, Cyrus F.; Warner, Ben; Seibt, Philipp; Waters, Michael; Fisher, Andrew J.; van Slageren, Joris; El Hallak, Fadi

    2014-03-01

    The coupling between charge and spin in nano-scale systems is of fundamental interest and also key for creating novel devices at this scale. There may be advantages in utilizing magnetism produced by f-shell states, especially in controlled local environments such as molecules. Recently, it has been shown that charge transport through a molecule can access f-shell states despite their localization. Here we show that for charge transport through DyPc2 that is strongly coupled to a copper surface it is possible to directly access the 4f spin. Spatially resolved scanning tunneling spectroscopy shows a variation in the amplitude of a Fano line shape near the Fermi energy, indicative of a Kondo effect due to screening of a localized spin coupled to a metallic continuum. The spin is attributed to the 4f states on Dy rather than the delocalized spin of an electron on the Pc ligands. This work demonstrates that the coupling to the surface can define which spins are present on a molecule as well as whether the spin state can be accessed in transport.

  16. 4 f occupancy and magnetism of rare-earth atoms adsorbed on metal substrates

    Science.gov (United States)

    Singha, Aparajita; Baltic, Romana; Donati, Fabio; Wäckerlin, Christian; Dreiser, Jan; Persichetti, Luca; Stepanow, Sebastian; Gambardella, Pietro; Rusponi, Stefano; Brune, Harald

    2017-12-01

    We report x-ray absorption spectroscopy and x-ray magnetic circular dichroism measurements as well as multiplet calculations for Dy, Ho, Er, and Tm atoms adsorbed on Pt(111), Cu(111), Ag(100), and Ag(111). In the gas phase, all four elements are divalent and we label their 4 f occupancy as 4 fn . Upon surface adsorption, and depending on the substrate, the atoms either remain in that state or become trivalent with 4 fn -1 configuration. The trivalent state is realized when the sum of the atomic correction energies (4 f →5 d promotion energy Ef d+ intershell coupling energy δ Ec ) is low and the surface binding energy is large. The latter correlates with a high substrate density of states at the Fermi level. The magnetocrystalline anisotropy of trivalent RE atoms is larger than the one of divalent RE atoms. We ascribe this to the significantly smaller covalent radius of the trivalent state compared to the divalent one for a given RE element. For a given valency of the RE atom, the anisotropy is determined by the overlap between the s p d states of the RE and the d states of the surface. For all investigated systems, the magnetization curves recorded at 2.5 K show absence of hysteresis indicating that magnetic relaxation is faster than about 10 s.

  17. WE-EF-210-07: Development of a Minimally Invasive Photo Acoustic Imaging System for Early Prostate Cancer Detection

    Energy Technology Data Exchange (ETDEWEB)

    Sano, M; Yousefi, S; Xing, L [Stanford University School of Medicine, Stanford, CA (United States)

    2015-06-15

    Purpose: The objective of this work is to design, implement and characterize a catheter-based ultrasound/photoacoustic imaging probe for early-diagnosis of prostate cancer and to aid in image-guided radiation therapy. Methods: The need to image across 6–10cm of tissue to image the whole prostate gland limits the resolution achievable with a transrectal ultrasound approach. In contrast, the urethra bisects the prostate gland, providing a minimally invasive pathway for deploying a high resolution ultrasound transducer. Utilizing a high-frequency (20MHz) ultrasound/photoacoustic probe, high-resolution structural and molecular imaging of the prostate tissue is possible. A custom 3D printed probe containing a high-frequency single-element ultrasound transducer is utilized. The diameter of the probe is designed to fit inside a Foley catheter and the probe is rotated around the central axis to achieve a circular B-scan. A custom ultrasound amplifier and receiver was set up to trigger the ultrasound pulse transmission and record the reflected signal. The reconstructed images were compared to images generated by traditional 5 MHz ultrasound transducers. Results: The preliminary results using the high-frequency ultrasound probe show that it is possible to resolve finely detailed information in a prostate tissue phantom that was not achievable with previous low-frequency ultrasound systems. Preliminary ultrasound imaging was performed on tissue mimicking phantom and sensitivity and signal-to-noise ratio of the catheter was measured. Conclusion: In order to achieve non-invasive, high-resolution, structural and molecular imaging for early-diagnosis and image-guided radiation therapy of the prostate tissue, a transurethral catheter was designed. Structural/molecular imaging using ultrasound/photoacoustic of the prostate tissue will allow for localization of hyper vascularized areas for early-stage prostate cancer diagnosis.

  18. Dynamic changes in eIF4F-mRNA interactions revealed by global analyses of environmental stress responses.

    Science.gov (United States)

    Costello, Joseph L; Kershaw, Christopher J; Castelli, Lydia M; Talavera, David; Rowe, William; Sims, Paul F G; Ashe, Mark P; Grant, Christopher M; Hubbard, Simon J; Pavitt, Graham D

    2017-10-27

    Translation factors eIF4E and eIF4G form eIF4F, which interacts with the messenger RNA (mRNA) 5' cap to promote ribosome recruitment and translation initiation. Variations in the association of eIF4F with individual mRNAs likely contribute to differences in translation initiation frequencies between mRNAs. As translation initiation is globally reprogrammed by environmental stresses, we were interested in determining whether eIF4F interactions with individual mRNAs are reprogrammed and how this may contribute to global environmental stress responses. Using a tagged-factor protein capture and RNA-sequencing (RNA-seq) approach, we have assessed how mRNA associations with eIF4E, eIF4G1 and eIF4G2 change globally in response to three defined stresses that each cause a rapid attenuation of protein synthesis: oxidative stress induced by hydrogen peroxide and nutrient stresses caused by amino acid or glucose withdrawal. We find that acute stress leads to dynamic and unexpected changes in eIF4F-mRNA interactions that are shared among each factor and across the stresses imposed. eIF4F-mRNA interactions stabilised by stress are predominantly associated with translational repression, while more actively initiating mRNAs become relatively depleted for eIF4F. Simultaneously, other mRNAs are insulated from these stress-induced changes in eIF4F association. Dynamic eIF4F-mRNA interaction changes are part of a coordinated early translational control response shared across environmental stresses. Our data are compatible with a model where multiple mRNA closed-loop complexes form with differing stability. Hence, unexpectedly, in the absence of other stabilising factors, rapid translation initiation on mRNAs correlates with less stable eIF4F interactions.

  19. Acoustic biosensors.

    Science.gov (United States)

    Fogel, Ronen; Limson, Janice; Seshia, Ashwin A

    2016-06-30

    Resonant and acoustic wave devices have been researched for several decades for application in the gravimetric sensing of a variety of biological and chemical analytes. These devices operate by coupling the measurand (e.g. analyte adsorption) as a modulation in the physical properties of the acoustic wave (e.g. resonant frequency, acoustic velocity, dissipation) that can then be correlated with the amount of adsorbed analyte. These devices can also be miniaturized with advantages in terms of cost, size and scalability, as well as potential additional features including integration with microfluidics and electronics, scaled sensitivities associated with smaller dimensions and higher operational frequencies, the ability to multiplex detection across arrays of hundreds of devices embedded in a single chip, increased throughput and the ability to interrogate a wider range of modes including within the same device. Additionally, device fabrication is often compatible with semiconductor volume batch manufacturing techniques enabling cost scalability and a high degree of precision and reproducibility in the manufacturing process. Integration with microfluidics handling also enables suitable sample pre-processing/separation/purification/amplification steps that could improve selectivity and the overall signal-to-noise ratio. Three device types are reviewed here: (i) bulk acoustic wave sensors, (ii) surface acoustic wave sensors, and (iii) micro/nano-electromechanical system (MEMS/NEMS) sensors. © 2016 The Author(s). Published by Portland Press Limited on behalf of the Biochemical Society.

  20. A pilot study of the characterization of hepatic tissue strain in children with cystic-fibrosis-associated liver disease (CFLD) by acoustic radiation force impulse imaging

    Energy Technology Data Exchange (ETDEWEB)

    Behrens, Christopher B.; Langholz, Juliane H.; Eiler, Jessika; Jenewein, Raphael; Fuchs, Konstantin; Alzen, Gerhard F.P. [University Hospital Giessen, Department of Pediatric Radiology, Giessen (Germany); Naehrlich, Lutz [University Hospital Giessen, Department of Pediatrics, Giessen (Germany); Harth, Sebastian; Krombach, Gabriele A. [University Hospital Giessen, Department of Radiology, Giessen (Germany)

    2013-03-15

    Progressive fibrotic alterations of liver tissue represent a major complication in children with cystic fibrosis. Correct assessment of cystic-fibrosis-associated liver disease (CFLD) in clinical routine is a challenging issue. Sonographic elastography based on acoustic radiation force impulse imaging (ARFI) is a new noninvasive approach for quantitatively assessing in vivo elasticity of biological tissues in many organs. To characterize ARFI elastography as a diagnostic tool to assess alteration of liver tissue elasticity related to cystic fibrosis in children. ARFI elastography and B-mode US imaging were performed in 36 children with cystic fibrosis. The children's clinical history and laboratory parameters were documented. According to the findings on conventional US, children were assigned to distinct groups indicating severity of hepatic tissue alterations. The relationship between US findings and respective elastography values was assessed. Additionally, differences between ARFI elastography values of each US group were statistically tested. Children with sonomorphologic characteristics of fibrotic tissue remodeling presented significantly increased values for tissue elasticity. Children with normal B-mode US or discrete signs of hepatic tissue alterations showed a tendency toward increased tissue stiffness indicating early tissue remodeling. Assessment of children with CFLD by means of ARFI elastography yields adequate results when compared to conventional US. For detection of early stages of liver disease with mild fibrotic reactions of hepatic tissue, ARFI elastography might offer diagnostic advantages over conventional US. Thus, liver stiffness measured by means of elastography might represent a valuable biological parameter for evaluation and follow-up of CFLD. (orig.)

  1. Scrutinising magnetic disorder through metastable 3d- and 4f-nanostructured alloys

    Energy Technology Data Exchange (ETDEWEB)

    Fernandez Barquin, L., E-mail: barquinl@unican.es [CITIMAC, Universidad de Cantabria, Santander 39005 (Spain); Alba Venero, D.; Echevarria-Bonet, C.; Garcia Calderon, R. [CITIMAC, Universidad de Cantabria, Santander 39005 (Spain); Rojas, D.P. [CITIMAC, Universidad de Cantabria, Santander 39005 (Spain); Dpto. Fisica, Universidad Carlos III de Madrid, Leganes 28911 (Spain); Rodriguez-Carvajal, J. [Lab. Leon Brillouin, CE-Saclay, Gif-sur-Yvette 91191, France and Inst. Laue-Langevin, BP156, Grenoble 38042 (France); Pankhurst, Q.A. [Royal Inst. Great Britain, Davy Faraday Res. Lab., London W1S 4BS (United Kingdom)

    2012-09-25

    Highlights: Black-Right-Pointing-Pointer Mechanical milling has been employed to produce 3d- and 4f-alloys in large quantities. Black-Right-Pointing-Pointer In FeCuAg, we show a multipattern Rietveld. It is formed by Fe(Cu) nanoparticles in a Ag matrix as a super spin glass. Black-Right-Pointing-Pointer The exchange of Ag by Au results in larger particles and the behaviour resembles that of a reentrant spin glass state. Black-Right-Pointing-Pointer 150 h milled TbAl{sub 2} shows a disordered Curie transition and a freezing associated to the nanostructure. - Abstract: Mechanical milling of magnetic alloys 3d-(Fe) and 4f-based (Tb) results in the promotion of magnetic disorder. In Fe{sub 22}Cu{sub 14}Ag{sub 64} the nanoscopic arrangement has been revealed by a very comprehensive multipattern Rietveld analysis using a combination of four sets of data including X-ray and neutron diffraction. The nanostructure is formed by Fe{sub 61}Cu{sub 39} particles of D = 4.6 nm with a collinear ferromagnetic structure in a metallic matrix constituted by D = 11.9 nm Ag nanoparticles. The creation of an ensemble of nanoparticles is favoured by the immiscible character of the starting metals. The nanostructured alloy presents a magnetic transition at around 160 K which cannot be considered as a pure single-domain blocking but affected by interparticle dipolar interactions. The latter is confirmed by the spin dynamics, displaying a critical slowing down of the AC-susceptibility and a definite peak of the non-linear susceptibility. When the matrix is alternatively formed by Au nanoparticles in the Fe{sub 14}Au{sub 86} (D = 77 nm) and Fe{sub 10}Cu{sub 10}Au{sub 80} (D = 35 nm) alloys, the magnetic response resembles that of a reentrant state as the milling time is not enough to reduce the particle size, triggering ferromagnetic interparticle coupling enhanced by a multidomain magnetic structure. In milled 4f-alloys formed by miscible Tb and Al, as TbAl{sub 2}, the production process

  2. Magnetism and superconductivity driven by identical 4f states in a heavy-fermion metal

    Energy Technology Data Exchange (ETDEWEB)

    Thompson, Joe E [Los Alamos National Laboratory; Nair, S [MAX PLANCK INST.; Stockert, O [MAX PLANCK INST.; Witte, U [INST. FUR FESTKORPERPHYSIK; Nicklas, M [MAX PLANCK INST.; Schedler, R [HELMHOLTZ - ZENTRUM; Bianchi, A [UC, IRVINE; Fisk, Z [UC, IRVINE; Wirth, S [MAX PLANCK INST.; Steglich, K [HELMHOLTZ - ZENTRUM

    2009-01-01

    The apparently inimical relationship between magnetism and superconductivity has come under increasing scrutiny in a wide range of material classes, where the free energy landscape conspires to bring them in close proximity to each other. Particularly enigmatic is the case when these phases microscopically interpenetrate, though the manner in which this can be accomplished remains to be fully comprehended. Here, we present combined measurements of elastic neutron scattering, magnetotransport, and heat capacity on a prototypical heavy fermion system, in which antiferromagnetism and superconductivity are observed. Monitoring the response of these states to the presence of the other, as well as to external thermal and magnetic perturbations, points to the possibility that they emerge from different parts of the Fermi surface. Therefore, a single 4f state could be both localized and itinerant, thus accounting for the coexistence of magnetism and superconductivity.

  3. Caliciviruses differ in their functional requirements for eIF4F components

    DEFF Research Database (Denmark)

    Chaudhry, Y.; Nayak, A.; Bordeleau, M-E.

    2006-01-01

    proteins can interact directly with the initiation factors eIF4E and eIF3. Translation initiation on feline calicivirus (FCV) RNA requires eIF4E because it is inhibited by recombinant 4E-BP1. However, to date, there have been no functional studies carried out with respect to norovirus translation...... initiation, because of a lack of a suitable source of VPg-linked viral RNA. We have now used the recently identified murine norovirus (MNV) as a model system for norovirus translation and have extended our previous studies with FCV RNA to examine the role of the other eIF4F components in translation...

  4. Active elastic metamaterials with applications in acoustics

    OpenAIRE

    Pope, Simon; Laalej, Hatim; Daley, Steve

    2012-01-01

    International audience; Elastic metamaterials provide a new approach to solving existing problems in acoustics. They have also been associated with novel concepts such as acoustic invisibility and subwavelength imaging. To be applied to many of the proposed applications a metamaterial would need to have the desired mass density and elastic moduli over a wide frequency band. To minimise scatter in acoustics applications the impedance of solid elastic metamaterials also need to be matched to th...

  5. Controlling sound with acoustic metamaterials

    Science.gov (United States)

    Cummer, Steven A.; Christensen, Johan; Alù, Andrea

    2016-03-01

    Acoustic metamaterials can manipulate and control sound waves in ways that are not possible in conventional materials. Metamaterials with zero, or even negative, refractive index for sound offer new possibilities for acoustic imaging and for the control of sound at subwavelength scales. The combination of transformation acoustics theory and highly anisotropic acoustic metamaterials enables precise control over the deformation of sound fields, which can be used, for example, to hide or cloak objects from incident acoustic energy. Active acoustic metamaterials use external control to create effective material properties that are not possible with passive structures and have led to the development of dynamically reconfigurable, loss-compensating and parity-time-symmetric materials for sound manipulation. Challenges remain, including the development of efficient techniques for fabricating large-scale metamaterial structures and converting laboratory experiments into useful devices. In this Review, we outline the designs and properties of materials with unusual acoustic parameters (for example, negative refractive index), discuss examples of extreme manipulation of sound and, finally, provide an overview of future directions in the field.

  6. Electronic and magnetic states of Ce 4f electrons in CeRh{sub 3}B{sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    Imada, S. [Graduate School of Engineering Science, Osaka University, Toyonaka 560-8531 (Japan)], E-mail: imada@mp.es.osaka-u.ac.jp; Yamasaki, A. [Faculty of Science and Engineering, Konan University, Kobe 658-8501 (Japan); Tsunekawa, M. [Graduate School of Engineering Science, Osaka University, Toyonaka 560-8531 (Japan); Higashiya, A. [SPring-8/RIKEN 1-1-1 Kouto, Mikazuki, Sayo, Hyogo 679-5148 (Japan); Sekiyama, A. [Graduate School of Engineering Science, Osaka University, Toyonaka 560-8531 (Japan); Sugawara, H. [Faculty of Integrated Arts and Sciences, Tokushima University, Tokushima 770-8502 (Japan); Sato, H. [Graduate School of Science, Tokyo Metropolitan University, Hachioji 192-0397 (Japan); Suga, S. [Graduate School of Engineering Science, Osaka University, Toyonaka 560-8531 (Japan)

    2007-05-15

    CeRh{sub 3}B{sub 2} is a ferromagnet with exceptionally high Curie temperature (T{sub C}=115 K) among the Ce compounds with no transition metal magnetic element. Magnetic circular dichroism of soft X-ray photoabsorption (XMCD) has revealed that the orbital angular momentum of Ce 4f electron is quenched to some extent. In addition, preferential occupation of the Ce 4f orbital pointing to the c-axis has been confirmed by the soft X-ray photoabsorption measurements with different geometries. On the other hand, resonant photoemission around the Ce 3d {yields} 4f photoabsorption edge has been adopted in order to disentangle the Ce 4f and Rh 4d components in the valence band. The Rh 4d spectrum is qualitatively consistent with the band structure calculation. Although the Ce 4f spectrum has a peak near the Fermi level, the spectral shape is qualitatively different from that of the typical Kondo materials and is rather similar to that of itinerant Ce 4f systems.

  7. Clinical application of Acoustic Radiation Force Impulse Imaging with Virtual Touch IQ in breast ultrasound: diagnostic performance and reproducibility of a new technique.

    Science.gov (United States)

    Kapetas, Panagiotis; Pinker-Domenig, Katja; Woitek, Ramona; Clauser, Paola; Bernathova, Maria; Spick, Claudio; Helbich, Thomas; Baltzer, Pascal A

    2017-02-01

    Background Virtual Touch IQ (VTIQ) is a novel technique of quantitative sonoelastography that applies acoustic radiation force impulse (ARFI). Purpose To evaluate breast ARFI imaging with VTIQ in the clinical setting, with regard to reproducibility and diagnostic performance, and to specify cutoff limits for the differentiation of benign and malignant lesions. Material and Methods This retrospective study included 83 patients with 85 breast lesions (51 benign, 34 malignant) who received ARFI imaging with VTIQ. Two independent ARFI measurements of each lesion were performed and shear wave velocities (SWV) of the lesion and the adjacent tissues were measured. A lesion-to-fat velocity ratio (L/F Ratio) was calculated for each lesion. Diagnostic performance of SWV measurements and L/F Ratios was evaluated with receiver operating curve (ROC) analysis. The intraclass correlation coefficient and Bland-Altman plots were used to evaluate measurement reproducibility. Results All measurements showed equal diagnostic performance, as measured by the area under the ROC curve (0.853 for SWV, 0.882 for the L/F Ratio). At a cutoff value of 3.23 m/s, sensitivity and specificity were 82.4% and 80.4%, respectively. An L/F Ratio cutoff value of 2.23 revealed a sensitivity and specificity of 89.7% and 76.5%. The reproducibility of the SWV measurements was moderate (limits of agreement, 40.3-44.4%) and higher than that of the L/F Ratios (54.5-60.2%). Conclusion ARFI imaging with VTIQ is a novel, moderately reproducible, quantitative elastography technique, which provides useful information for the differentiation of benign and malignant breast lesions in the clinical setting.

  8. Acoustic microscopy

    CERN Document Server

    Briggs, Andrew

    2010-01-01

    For many years 'Acoustic Microscopy' has been the definitive book on the subject. A key development since it was first published has been the development of ultrasonic force microscopy. This edition has a major new chapter on this technique and its applications.

  9. PVT Degradation Studies: Acoustic Diagnostics

    Energy Technology Data Exchange (ETDEWEB)

    Dib, Gerges [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Tucker, Brian J. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Kouzes, Richard T. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Smith, Philip J. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

    2017-04-01

    Under certain environmental conditions, polyvinyl toluene (PVT) plastic scintillator has been observed to undergo internal fogging. This document reports on a study of acoustic techniques to determine whether they can provide a diagnostic for the fogging of PVT. Different ultrasound techniques were employed for detecting the level of internal fogging in PVT, including wave velocity measurements, attenuation, nonlinear acoustics, and acoustic microscopy. The results indicate that there are linear relations between the wave velocity and wave attenuation with the level of internal fogging. The effects of fogging on ultrasound wave attenuation is further verified by acoustic microscopy imaging, where regions with fog in the specimen demonstration higher levels of attenuation compared to clear regions. Results from the nonlinear ultrasound measurements were inconclusive due to high sensitivities to transducer coupling and fixture variabilities.

  10. Acoustic Characterization of Mesoscale Objects

    Energy Technology Data Exchange (ETDEWEB)

    Chinn, D; Huber, R; Chambers, D; Cole, G; Balogun, O; Spicer, J; Murray, T

    2007-03-13

    This report describes the science and engineering performed to provide state-of-the-art acoustic capabilities for nondestructively characterizing mesoscale (millimeter-sized) objects--allowing micrometer resolution over the objects entire volume. Materials and structures used in mesoscale objects necessitate the use of (1) GHz acoustic frequencies and (2) non-contacting laser generation and detection of acoustic waves. This effort demonstrated that acoustic methods at gigahertz frequencies have the necessary penetration depth and spatial resolution to effectively detect density discontinuities, gaps, and delaminations. A prototype laser-based ultrasonic system was designed and built. The system uses a micro-chip laser for excitation of broadband ultrasonic waves with frequency components reaching 1.0 GHz, and a path-stabilized Michelson interferometer for detection. The proof-of-concept for mesoscale characterization is demonstrated by imaging a micro-fabricated etched pattern in a 70 {micro}m thick silicon wafer.

  11. Holograms for acoustics.

    Science.gov (United States)

    Melde, Kai; Mark, Andrew G; Qiu, Tian; Fischer, Peer

    2016-09-22

    Holographic techniques are fundamental to applications such as volumetric displays, high-density data storage and optical tweezers that require spatial control of intricate optical or acoustic fields within a three-dimensional volume. The basis of holography is spatial storage of the phase and/or amplitude profile of the desired wavefront in a manner that allows that wavefront to be reconstructed by interference when the hologram is illuminated with a suitable coherent source. Modern computer-generated holography skips the process of recording a hologram from a physical scene, and instead calculates the required phase profile before rendering it for reconstruction. In ultrasound applications, the phase profile is typically generated by discrete and independently driven ultrasound sources; however, these can only be used in small numbers, which limits the complexity or degrees of freedom that can be attained in the wavefront. Here we introduce monolithic acoustic holograms, which can reconstruct diffraction-limited acoustic pressure fields and thus arbitrary ultrasound beams. We use rapid fabrication to craft the holograms and achieve reconstruction degrees of freedom two orders of magnitude higher than commercial phased array sources. The technique is inexpensive, appropriate for both transmission and reflection elements, and scales well to higher information content, larger aperture size and higher power. The complex three-dimensional pressure and phase distributions produced by these acoustic holograms allow us to demonstrate new approaches to controlled ultrasonic manipulation of solids in water, and of liquids and solids in air. We expect that acoustic holograms will enable new capabilities in beam-steering and the contactless transfer of power, improve medical imaging, and drive new applications of ultrasound.

  12. Detection of non-alcoholic steatohepatitis in patients with morbid obesity before bariatric surgery: preliminary evaluation with acoustic radiation force impulse imaging

    Energy Technology Data Exchange (ETDEWEB)

    Guzman-Aroca, F.; Reus, M.; Dios Berna-Serna, Juan de [Virgen de la Arrixaca University Hospital, Department of of Radiology, El Palmar, Murcia (Spain); Frutos-Bernal, M.D.; Lujan-Mompean, J.A.; Parrilla, P. [Virgen de la Arrixaca University Hospital, Department of Surgery, El Palmar, Murcia (Spain); Bas, A. [Virgen de la Arrixaca University Hospital, Department of Pathology, El Palmar, Murcia (Spain)

    2012-11-15

    To investigate the utility of acoustic radiation force impulse (ARFI) imaging, with the determination of shear wave velocity (SWV), to differentiate non-alcoholic fatty liver disease (NAFLD) from non-alcoholic steatohepatitis (NASH) in patients with morbid obesity before bariatric surgery. Thirty-two patients with morbid obesity were evaluated with ARFI and conventional ultrasound before bariatric surgery. The ARFI and ultrasound results were compared with liver biopsy findings, which is the reference standard. The patients were classed according to their histological findings into three groups: group A, simple steatosis; group B, inflammation; and group C, fibrosis. The median SWV was 1.57 {+-} 0.79 m/s. Hepatic alterations were observed in the histopathological findings for all the patients in the study (100 %), with the results of the laboratory tests proving normal. Differences in SWV were also observed between groups A, B and C: 1.34 {+-} 0.90 m/s, 1.55 {+-} 0.79 m/s and 1.86 {+-} 0.75 m/s (P < 0.001), respectively. The Az for differentiating NAFLD from NASH or fibrosis was 0.899 (optimal cut-off value 1.3 m/s; sensitivity 85 %; specificity 83.3 %). The ARFI technique is a useful diagnostic tool for differentiating NAFLD from NASH in asymptomatic patients with morbid obesity. (orig.)

  13. Regulation of the orphan nuclear receptor Nr2f2 by the DFNA15 deafness gene Pou4f3.

    Directory of Open Access Journals (Sweden)

    Chrysostomos Tornari

    Full Text Available Hair cells are the mechanotransducing cells of the inner ear that are essential for hearing and balance. POU4F3--a POU-domain transcription factor selectively expressed by these cells--has been shown to be essential for hair cell differentiation and survival in mice and its mutation in humans underlies late-onset progressive hearing loss (DFNA15. The downstream targets of POU4F3 are required for hair cell differentiation and survival. We aimed to identify such targets in order to elucidate the molecular pathways involved in hair cell production and maintenance. The orphan thyroid nuclear receptor Nr2f2 was identified as a POU4F3 target using a subtractive hybridization strategy and EMSA analysis showed that POU4F3 binds to two sites in the Nr2f2 5' flanking region. These sites were shown to be required for POU4F3 activation as their mutation leads to a reduction in the response of an Nr2f2 5' flanking region reporter construct to POU4F3. Immunocytochemistry was carried out in the developing and adult inner ear in order to investigate the relevance of this interaction in hearing. NR2F2 expression in the postnatal mouse organ of Corti was shown to be detectable in all sensory epithelia examined and characterised. These data demonstrate that Nr2f2 is a direct target of POU4F3 in vitro and that this regulatory relationship may be relevant to hair cell development and survival.

  14. Inspection of copper canisters for spent nuclear fuel by means of ultrasound. Phased arrays, ultrasonic imaging and nonlinear acoustics

    Energy Technology Data Exchange (ETDEWEB)

    Stepinski, Tadeusz (ed.); Ping Wu; Wennerstroem, Erik [Uppsala Univ. (Sweden). Signals and Systems

    2004-09-01

    This report contains the research results concerning advanced ultrasound for the inspection of copper canisters for spent nuclear fuel obtained at Signals and Systems, Uppsala University in years 2003/2004. After a short introduction a review of beam forming fundamentals required for proper understanding phased array operation is included. The factors that determine lateral resolution during ultrasonic imaging of flaws in solids are analyzed and results of simulations modelling contact inspection of copper are presented. In the second chapter an improved synthetic aperture imaging (SAI) technique is introduced. The proposed SAI technique is characterized by an enhanced lateral resolution compared with the previously proposed extended synthetic aperture focusing technique (ESAFT). The enhancement of imaging performance is achieved due to more realistic assumption concerning the probability density function of scatterers in the region of interest. The proposed technique takes the form of a two-step algorithm using the result obtained in the first step as a prior for the second step. Final chapter contains summary of our recent experimental and theoretical research on nonlinear ultrasonics of unbounded interfaces. A new theoretical model for rough interfaces is developed, and the experimental results from the copper specimens that mimic contact cracks of different types are presented. Derivation of the theory and selected measurement results are given in appendix.

  15. Non-intrusive telemetry applications in the oilsands: from visible light and x-ray video to acoustic imaging and spectroscopy

    Science.gov (United States)

    Shaw, John M.

    2013-06-01

    While the production, transport and refining of oils from the oilsands of Alberta, and comparable resources elsewhere is performed at industrial scales, numerous technical and technological challenges and opportunities persist due to the ill defined nature of the resource. For example, bitumen and heavy oil comprise multiple bulk phases, self-organizing constituents at the microscale (liquid crystals) and the nano scale. There are no quantitative measures available at the molecular level. Non-intrusive telemetry is providing promising paths toward solutions, be they enabling technologies targeting process design, development or optimization, or more prosaic process control or process monitoring applications. Operation examples include automated large object and poor quality ore during mining, and monitoring the thickness and location of oil water interfacial zones within separation vessels. These applications involve real-time video image processing. X-ray transmission video imaging is used to enumerate organic phases present within a vessel, and to detect individual phase volumes, densities and elemental compositions. This is an enabling technology that provides phase equilibrium and phase composition data for production and refining process development, and fluid property myth debunking. A high-resolution two-dimensional acoustic mapping technique now at the proof of concept stage is expected to provide simultaneous fluid flow and fluid composition data within porous inorganic media. Again this is an enabling technology targeting visualization of diverse oil production process fundamentals at the pore scale. Far infrared spectroscopy coupled with detailed quantum mechanical calculations, may provide characteristic molecular motifs and intermolecular association data required for fluid characterization and process modeling. X-ray scattering (SAXS/WAXS/USAXS) provides characteristic supramolecular structure information that impacts fluid rheology and process

  16. Imaging feedback for histotripsy by characterizing dynamics of acoustic radiation force impulse (ARFI)-induced shear waves excited in a treated volume.

    Science.gov (United States)

    Wang, Tzu-Yin; Hall, Timothy L; Xu, Zhen; Fowlkes, J Brian; Cain, Charles A

    2014-07-01

    Our previous study indicated that shear waves decay and propagate at a lower speed as they propagate into a tissue volume mechanically fractionated by histotripsy. In this paper, we hypothesize that the change in the shear dynamics is related to the degree of tissue fractionation, and can be used to predict histotripsy treatment outcomes. To test this hypothesis, lesions with different degrees of tissue fractionation were created in agar-graphite tissue phantoms and ex vivo kidneys with increasing numbers of therapy pulses, from 0 to 2000 pulses per treatment location. The therapy pulses were 3-cycle 750-kHz focused ultrasound delivered at a peak negative/positive pressure of 17/108 MPa and a repetition rate of 50 Hz. The shear waves were excited by acoustic radiation force impulse (ARFI) focused at the center of the lesion. The spatial and temporal behavior of the propagating shear waves was measured with ultrasound plane wave imaging. The temporal displacement profile at a lateral location 10 mm offset to the shear excitation region was detected with M-mode imaging. The decay and delay of the shear waves were quantitatively characterized on the temporal displacement profile. Results showed significant changes in two characteristics on the temporal displacement profile: the peak-to-peak displacement decayed exponentially with increasing numbers of therapy pulses; the relative time-to-peak displacement increased with increasing numbers of therapy pulses, and appeared to saturate at higher numbers of pulses. Correspondingly, the degree of tissues fractionation, as indicated by the percentage of structurally intact cell nuclei, decreased exponentially with increasing numbers of therapy pulses. Strong linear correlations were found between the two characteristics and the degree of tissue fractionation. These results suggest that the characteristics of the shear temporal displacement profile may provide useful feedback information regarding the treatment outcomes.

  17. Implementation and Comparison of Acoustic Travel-Time Measurement Procedures for the Helioseismic and Magnetic Imager Time-Distance Helioseismology Pipeline

    Science.gov (United States)

    Couvidat, S.; Zhao, J.; Birch, A. C.; Kosovichev, A. G.; Duvall, T. L., Jr.; Parchevsky, K.; Scherrer, P. H.

    2009-01-01

    The Helioseismic and Magnetic Imager (HMI) instrument on board the Solar Dynamics Observatory (SDO) satellite is designed to produce high-resolution Doppler velocity maps of oscillations at the solar surface with high temporal cadence. To take advantage of these high-quality oscillation data, a time-distance helioseismology pipeline has been implemented at the Joint Science Operations Center (JSOC) at Stanford University. The aim of this pipeline is to generate maps of acoustic travel times from oscillations on the solar surface, and to infer subsurface 3D flow velocities and sound-speed perturbations. The wave travel times are measured from cross covariances of the observed solar oscillation signals. For implementation into the pipeline we have investigated three different travel-time definitions developed in time-distance helioseismology: a Gabor wavelet fitting (Kosovichev and Duvall, 1997), a minimization relative to a reference cross-covariance function (Gizon and Birch, 2002), and a linearized version of the minimization method (Gizon and Birch, 2004). Using Doppler velocity data from the Michelson Doppler Imager (MDI) instrument on board SOHO, we tested and compared these definitions for the mean and difference travel-time perturbations measured from reciprocal signals. Although all three procedures return similar travel times in a quiet Sun region, the method of Gizon and Birch (2004) gives travel times that are significantly different from the others in a magnetic (active) region. Thus, for the pipeline implementation we chose the procedures of Kosovichev and Duvall (1997) and Gizon and Birch (2002). We investigated the relationships among these three travel-time definitions, their sensitivities to fitting parameters, and estimated the random errors they produce

  18. Implementation and Comparison of Acoustic Travel-Time Measurement Procedures for the Solar Dynamics Observatory-Helioseismic and Magnetic Imager Time-Distance Helioseismology Pipeline

    Science.gov (United States)

    Couvidat, S.; Zhao, J.; Birch, A. C.; Kosovichev, A. G.; Duvall, Thomas L., Jr.; Parchevsky, K.; Scherrer, P. H.

    2010-01-01

    The Helioseismic and Magnetic Imager (HMI) instrument onboard the Solar Dynamics Observatory (SDO) satellite is designed to produce high-resolution Doppler-velocity maps of oscillations at the solar surface with high temporal cadence. To take advantage of these high-quality oscillation data, a time - distance helioseismology pipeline (Zhao et al., Solar Phys. submitted, 2010) has been implemented at the Joint Science Operations Center (JSOC) at Stanford University. The aim of this pipeline is to generate maps of acoustic travel times from oscillations on the solar surface, and to infer subsurface 3D flow velocities and sound-speed perturbations. The wave travel times are measured from cross-covariances of the observed solar oscillation signals. For implementation into the pipeline we have investigated three different travel-time definitions developed in time - distance helioseismology: a Gabor-wavelet fitting (Kosovichev and Duvall, SCORE'96: Solar Convection and Oscillations and Their Relationship, ASSL, Dordrecht, 241, 1997), a minimization relative to a reference cross-covariance function (Gizon and Birch, Astrophys. J. 571, 966, 2002), and a linearized version of the minimization method (Gizon and Birch, Astrophys. J. 614, 472, 2004). Using Doppler-velocity data from the Michelson Doppler Imager (MDI) instrument onboard SOHO, we tested and compared these definitions for the mean and difference traveltime perturbations measured from reciprocal signals. Although all three procedures return similar travel times in a quiet-Sun region, the method of Gizon and Birch (Astrophys. J. 614, 472, 2004) gives travel times that are significantly different from the others in a magnetic (active) region. Thus, for the pipeline implementation we chose the procedures of Kosovichev and Duvall (SCORE'96: Solar Convection and Oscillations and Their Relationship, ASSL, Dordrecht, 241, 1997) and Gizon and Birch (Astrophys. J. 571, 966, 2002). We investigated the relationships among

  19. Comparative study of Nd(3+) emission from 4f{sup 2} 5d and 4f{sup 3} configurations induced by multiphotonic process in YLF, GLF and LLF crystals; Estudo comparativo das emissoes do Nd(3+) nas configuracoes de 4f{sup 2} 5d e 4f{sup 3} induzidas pela excitacao multifotonica em cristais de YLF, GLF e LLF

    Energy Technology Data Exchange (ETDEWEB)

    Librantz, Andre Felipe Henriques

    2000-07-01

    Nd{sup 3+} ultraviolet fluorescence induced by multiphotonic laser excitations was studied in Nd-doped YLiF{sub 4} (YLF) and LuLiF{sub 4} (LLF) crystals by using the time resolved spectroscopy technique. The UV luminescences are due to transitions between the 4f {sup 2}5d and the 4f{sup 3} electronic configurations of Nd{sup 3+} ions. The 4f{sup 2}5d configuration can be reached by direct pumping the UV transition or by multiphotonic excitation, both processes give raise to the UV emission band with a structure due to the strong phonon coupling, expected for a 5d orbital involvement in the transition. The multiphotonic excitation process is due to three photons (532 nm) sequential absorptions of 532 nm-photons by metastable levels of the 4f{sup 3} configuration splitted by crystalline local field. The sequential excitation of Nd by the pumping laser is attributed to the {sup 4}I{sub 9/2}+532nm {yields}{sup 4}G{sub 7/2} ground state absorption followed by the{sup 4}G{sub 7/2} +532 nm {yields}2{sup F}{sub 5/2} and 2{sup F}{sub 5/2} +532 nm {yields} 4f {sup 2}5d excited state absorptions. The UV emissions due to 4f {sup 2}5d configuration are parity allowed, having lifetime of 35 ns in contrast to UV emissions from 4f{sup 3} configuration which are induced by two absorption steps and are parity forbidden showing longer lifetime of 8{mu}s and narrow tines. The polarization effects of the UV emissions were studied and their behavior are dependent on the excited state configuration involving or not the 5d orbital. The allowed UV emissions positions were affected by the host variation more than the ones originating from the 4f{sup 3} configuration as expected. The electronic energy of the 4f {sup 2}5d configuration shifts to lower energy when increasing the crystal field. (author)

  20. Acoustic Territoriality

    DEFF Research Database (Denmark)

    Kreutzfeldt, Jacob

    2011-01-01

    Under the heading of "Gang i København" a number of initiatives was presented by the Lord Mayer and the Technical and Environmental Mayer of Copenhagen in May 2006. The aim of the initiative, which roughly translates to Lively Copenhagen, was both to make Copenhagen a livelier city in terms of ci...... this article outline a few approaches to a theory of acoustic territoriality....

  1. Acoustic chaos

    Energy Technology Data Exchange (ETDEWEB)

    Lauterborn, W.; Parlitz, U. [Drittes Physikalisches Institut, Universitaet Goettingen, D-37073 Goettingen (Germany); Holzfuss, J.; Billo, A. [Institut fuer Angewandte Physik, Technische Hochschule Darmstadt, D-64289 Darmstadt (Germany); Akhatov, I. [Department of Continuous Media Mechanics, Bashkir State University, Ufa 450074 (Russia)

    1996-06-01

    Acoustic cavitation, a complex, spatio-temporal dynamical system, is investigated with respect to its chaotic properties. The sound output, the {open_quote}{open_quote}noise{close_quote}{close_quote}, is subjected to time series analysis. The spatial dynamics of the bubble filaments is captured by high speed holographic cinematography and subsequent digital picture processing from the holograms. Theoretical models are put forward for describing the pattern formation. {copyright} {ital 1996 American Institute of Physics.}

  2. A 4F2-cross-point phase change memory using nano-crystalline doped GeSbTe material

    Science.gov (United States)

    Takaura, Norikatsu; Kinoshita, Masaharu; Tai, Mitsuharu; Ohyanagi, Takasumi; Akita, Kenichi; Morikawa, Takahiro

    2015-04-01

    This paper reports on the use of nano-crystalline doped GeSbTe, or nano-GST, to fabricate a cross-point phase change memory with 4F2 cell size and test results obtained for it. We show the characteristics of a poly-Si diode select device with a high on-off ratio and data writing in a 4F2 memory cell array. The advantages of nano-GST over conventional GeSbTe are presented in terms of neighboring disturbance and 4F2 cross-point array formation. The memory cells’ high drivability, low power, and selective write and read performances are demonstrated. The scalability of the diode current density is also presented.

  3. Photoelectron spectroscopy of Ce(η-C 5H 5) 3 - Accessing two ion states on 4f ionization

    Science.gov (United States)

    Coreno, Marcello; de Simone, Monica; Green, Jennifer C.; Kaltsoyannis, Nikolas; Narband, Naima; Sella, Andrea

    2006-12-01

    Valence PES have been measured for Ce(η-C 5H 5) 3 in the gas phase with photon energies of 24-135 eV. Two ion states arising from ionization of the single 4f electron are unambiguously characterized by the intensity behaviour of the associated bands. Assignment is made using a VBCI model where purely ionic components are allowed to mix under configuration interaction. Thus the ground state of the [Ce(η-C 5H 5) 3] + cation is described as a mixture of two configurations of 1A 1 symmetry, one with no 4f electron, Lf 0 and one with a single 4f electron interacting strongly with a hole of the same symmetry in the ligand shell, L -1f 1.

  4. Acoustic Neuroma Association

    Science.gov (United States)

    ... EVENTS DONATE NEWS Home Learn Back Learn about acoustic neuroma AN Facts What is acoustic neuroma? Diagnosing ... Brain Freeze ? READ MORE Read More What is acoustic neuroma? Identifying an AN Learn More Get Info ...

  5. Differentiating malignant from benign breast tumors on acoustic radiation force impulse imaging using fuzzy-based neural networks with principle component analysis

    Science.gov (United States)

    Liu, Hsiao-Chuan; Chou, Yi-Hong; Tiu, Chui-Mei; Hsieh, Chi-Wen; Liu, Brent; Shung, K. Kirk

    2017-03-01

    Many modalities have been developed as screening tools for breast cancer. A new screening method called acoustic radiation force impulse (ARFI) imaging was created for distinguishing breast lesions based on localized tissue displacement. This displacement was quantitated by virtual touch tissue imaging (VTI). However, VTIs sometimes express reverse results to intensity information in clinical observation. In the study, a fuzzy-based neural network with principle component analysis (PCA) was proposed to differentiate texture patterns of malignant breast from benign tumors. Eighty VTIs were randomly retrospected. Thirty four patients were determined as BI-RADS category 2 or 3, and the rest of them were determined as BI-RADS category 4 or 5 by two leading radiologists. Morphological method and Boolean algebra were performed as the image preprocessing to acquire region of interests (ROIs) on VTIs. Twenty four quantitative parameters deriving from first-order statistics (FOS), fractal dimension and gray level co-occurrence matrix (GLCM) were utilized to analyze the texture pattern of breast tumors on VTIs. PCA was employed to reduce the dimension of features. Fuzzy-based neural network as a classifier to differentiate malignant from benign breast tumors. Independent samples test was used to examine the significance of the difference between benign and malignant breast tumors. The area Az under the receiver operator characteristic (ROC) curve, sensitivity, specificity and accuracy were calculated to evaluate the performance of the system. Most all of texture parameters present significant difference between malignant and benign tumors with p-value of less than 0.05 except the average of fractal dimension. For all features classified by fuzzy-based neural network, the sensitivity, specificity, accuracy and Az were 95.7%, 97.1%, 95% and 0.964, respectively. However, the sensitivity, specificity, accuracy and Az can be increased to 100%, 97.1%, 98.8% and 0.985, respectively

  6. Spatiotemporally resolved granular acoustics

    Science.gov (United States)

    Owens, Eli; Daniels, Karen

    2011-03-01

    Acoustic techniques provide a non-invasive method of characterizing granular material properties; however, there are many challenges in formulating accurate models of sound propagation due to the inherently heterogeneous nature of granular materials. In order to quantify acoustic responses in space and time, we perform experiments in a photoelastic granular material in which the internal stress pattern (in the form of force chains) is visible. We utilize two complementary methods, high-speed imaging and piezoelectric transduction, to provide particle-scale measurements of the amplitude of the acoustic wave. We observe that the average wave amplitude is largest within particles experiencing the largest forces. The force-dependence of this amplitude is in qualitative agreement with a simple Hertzian-like model for contact area. In addition, we investigate the power spectrum of the propagating signal using the piezoelectric sensors. For a Gaussian wave packet input, we observe a broad spectrum of transmitted frequencies below the driving frequency, and we quantify the characteristic frequencies and corresponding length scales of our material as the system pressure is varied.

  7. Description of an optimized ChIP-seq analysis pipeline dedicated to genome wide identification of E4F1 binding sites in primary and transformed MEFs

    Directory of Open Access Journals (Sweden)

    Thibault Houlès

    2015-09-01

    To identify this program, we performed E4F1 ChIP-seq analyses in primary Mouse Embryonic Fibroblasts (MEF and in p53−/−, H-RasV12-transformed MEFs. The program directly controlled by E4F1 was obtained by intersecting the lists of E4F1 genomic targets with the lists of genes differentially expressed in E4F1 KO and E4F1 WT cells (Rodier et al., 2015. We describe hereby how we improved our ChIP-seq analyses workflow by applying prefilters on raw data and by using a combination of two publicly available programs, Cisgenome and QESEQ.

  8. R and D studies of a RICH detector using pressurized C{sub 4}F{sub 8}O radiator gas and a CsI-based gaseous photon detector

    Energy Technology Data Exchange (ETDEWEB)

    Agócs, A.G. [Wigner RCP of the HAS, Budapest (Hungary); Barile, F. [INFN Sezione di Bari and Universitá degli Studi di Bari, Dipartimento Interateneo di Fisica M. Merlin, Bari (Italy); Barnaföldi, G.G. [Wigner RCP of the HAS, Budapest (Hungary); Bellwied, R. [University of Houston, Houston (United States); Bencédi, G.; Bencze, G.; Berényi, D.; Boldizsár, L. [Wigner RCP of the HAS, Budapest (Hungary); Chattopadhyay, S. [Saha Institute, Kolkata (India); Chinellato, D.D. [University of Houston, Houston (United States); Cindolo, F. [University of Salerno, Salerno (Italy); Das, D.; Das, K.; Das-Bose, L. [Saha Institute, Kolkata (India); De Cataldo, G.; Di Bari, D. [INFN Sezione di Bari and Universitá degli Studi di Bari, Dipartimento Interateneo di Fisica M. Merlin, Bari (Italy); Di Mauro, A., E-mail: antonio.di.mauro@cern.ch [CERN, CH1211 Geneva 23 (Switzerland); Futó, E. [Wigner RCP of the HAS, Budapest (Hungary); Garcia, E. [Chicago State University, Chicago, IL (United States); Hamar, G. [Wigner RCP of the HAS, Budapest (Hungary); and others

    2013-12-21

    We report on studies of layout and performance of a new Ring Imaging Cherenkov detector using for the first time pressurized C{sub 4}F{sub 8}O radiator gas and a photon detector consisting of a MWPC equipped with a CsI photocathode. In particular, we present here the results of beam tests of a MWPC having an adjustable anode–cathode gap, aiming at the optimization of single photoelectron detection and Cherenkov angle resolution. This system was proposed as a Very High Momentum Particle Identification (VHMPID) upgrade for the ALICE experiment at LHC to provide charged hadron track-by-track identification in the momentum range 5–25 GeV/c. -- Highlights: •The concept and design of a novel RICH counter operated with pressurized gaseous Cherenkov radiator have been validated. •We used for the first time C{sub 4}F{sub 8}O gaseous Cherenkov radiator pressurized up to 3.5 atm in a RICH counter. •The refractive index of C{sub 4}F{sub 8}O in the UV range is similar to the per-mil level to that of C{sub 4}F{sub 10}. •A variable gap MWPC has been used to optimize the layout of the gaseous photon counter, based on CsI photocathodes and MWPC, for the detection of single photoelectrons.

  9. Acoustic Imaging of Selected Areas of Gdansk Bay with the Aid of Parametric Echosounder and Side-Scan Sonar

    Directory of Open Access Journals (Sweden)

    Grelowska Grażyna

    2017-12-01

    Full Text Available The article presents and analyses the data recorded during sounding of the Gdansk Bay seabed with the aid of a parametric echosounder and a side-scan sonar. The accuracy of seabed structure examination, as a condition for obtaining valuable results, requires correct configuration of echolocation devices and proper calibration of peripheral devices, such as the survey unit geographical position sensor - GPS, the navigation unit, the MRU-Z sensor of pitch, roll and heave, and the sound velocity meter, which deliver the data to the bathymetric measurement system. Parametric seabed profilers deliver two types of data: the envelope, and the detailed echo signal without processing. The envelope is used for data visualisation in the form of online echograms, while the echo signal is stored for further analyses, to be performed using dedicated software or, after relevant conversion, in arbitrary programming environment1. The presented data analysis is illustrated by selected sample images recorded by the parametric echosounder and the side-scan sonar during Gdansk Bay sounding.

  10. Normal values of liver shear wave velocity in healthy children assessed by acoustic radiation force impulse imaging using a convex probe and a linear probe.

    Science.gov (United States)

    Fontanilla, Teresa; Cañas, Teresa; Macia, Araceli; Alfageme, Marta; Gutierrez Junquera, Carolina; Malalana, Ana; Luz Cilleruelo, Maria; Roman, Enriqueta; Miralles, Maria

    2014-03-01

    Acoustic radiation force impulse (ARFI) is an image-guided ultrasound elastography method that allows quantification of liver stiffness by measurement of shear wave velocity. One purpose of the work described in this article was to determine the normal liver stiffness values of healthy children using ARFI with two different probes, 4 C1 and 9 L4. Another purpose was to evaluate the effects of site of measurement, age, gender and body mass index on liver stiffness values. This prospective study included 60 healthy children (newborn to 14 y) divided into four age groups. One thousand two hundred ARFI measurements were performed, that is, 20 measurements per patient (5 measurements in each lobe, with each probe). Means, standard deviations (SD) and confidence intervals for velocity were calculated for each hepatic lobe and each probe in each age group and for the whole group. Mean shear wave velocity measured in the right lobe was 1.19 ± 0.04 m/s (SD = 0.13) with the 4 C1 transducer and 1.15 ± 0.04 m/s (SD = 0.15) with the 9 L4 transducer. Age had a small effect on shear wave measurements. Body mass index and sex had no significant effects on ARFI values, whereas site of measurement had a significant effect, with lower ARFI values in the right hepatic lobe. ARFI is a non-invasive technique that is feasible to perform in children with both the 4 C1 and 9 L4 probes. The aforementioned velocity values obtained in the right lobe may be used as reference values for normal liver stiffness in children. Published by Elsevier Inc.

  11. CLEC4F is an inducible C-type lectin in F4/80-positive cells and is involved in alpha-galactosylceramide presentation in liver.

    Directory of Open Access Journals (Sweden)

    Chih-Ya Yang

    Full Text Available CLEC4F, a member of C-type lectin, was first purified from rat liver extract with high binding affinity to fucose, galactose (Gal, N-acetylgalactosamine (GalNAc, and un-sialylated glucosphingolipids with GalNAc or Gal terminus. However, the biological functions of CLEC4F have not been elucidated. To address this question, we examined the expression and distribution of murine CLEC4F, determined its binding specificity by glycan array, and investigated its function using CLEC4F knockout (Clec4f-/- mice. We found that CLEC4F is a heavily glycosylated membrane protein co-expressed with F4/80 on Kupffer cells. In contrast to F4/80, CLEC4F is detectable in fetal livers at embryonic day 11.5 (E11.5 but not in yolk sac, suggesting the expression of CLEC4F is induced as cells migrate from yolk cells to the liver. Even though CLEC4F is not detectable in tissues outside liver, both residential Kupffer cells and infiltrating mononuclear cells surrounding liver abscesses are CLEC4F-positive upon Listeria monocytogenes (L. monocytogenes infection. While CLEC4F has strong binding to Gal and GalNAc, terminal fucosylation inhibits CLEC4F recognition to several glycans such as Fucosyl GM1, Globo H, Bb3∼4 and other fucosyl-glycans. Moreover, CLEC4F interacts with alpha-galactosylceramide (α-GalCer in a calcium-dependent manner and participates in the presentation of α-GalCer to natural killer T (NKT cells. This suggests that CLEC4F is a C-type lectin with diverse binding specificity expressed on residential Kupffer cells and infiltrating monocytes in the liver, and may play an important role to modulate glycolipids presentation on Kupffer cells.

  12. Air-coupled acoustic thermography for in-situ evaluation

    Science.gov (United States)

    Zalameda, Joseph N. (Inventor); Winfree, William P. (Inventor); Yost, William T. (Inventor)

    2010-01-01

    Acoustic thermography uses a housing configured for thermal, acoustic and infrared radiation shielding. For in-situ applications, the housing has an open side adapted to be sealingly coupled to a surface region of a structure such that an enclosed chamber filled with air is defined. One or more acoustic sources are positioned to direct acoustic waves through the air in the enclosed chamber and towards the surface region. To activate and control each acoustic source, a pulsed signal is applied thereto. An infrared imager focused on the surface region detects a thermal image of the surface region. A data capture device records the thermal image in synchronicity with each pulse of the pulsed signal such that a time series of thermal images is generated. For enhanced sensitivity and/or repeatability, sound and/or vibrations at the surface region can be used in feedback control of the pulsed signal applied to the acoustic sources.

  13. Carbothermal reduction synthesis of carbon coated Na2FePO4F for lithium ion batteries

    Science.gov (United States)

    Cui, Dongming; Chen, Shasha; Han, Chang; Ai, Changchun; Yuan, Liangjie

    2016-01-01

    Carbon coated spherical Na2FePO4F particles with typical diameters from 500 nm to 1 μm have been synthesized through an economical carbothermal reduction method with a simple apparatus. Mixed carbon source consists of citric acid and phenolic resin can form highly graphitized carbon and remarkably improve the electrical conductivity. When cycled against lithium, Na2FePO4F/C cathodes deliver maximum discharge capacity of 119 mAh g-1 at a low rate of 0.05 C. Reversible capacity of 110 mAh g-1, 74 mAh g-1 and 52 mAh g-1 can be obtained at 0.1 C, 1 C and 2 C rates, respectively. And after 30 cycles at 0.1 C, 91% of the discharge capacity can still be maintained. The electrochemical kinetic characteristic of electrode material is investigated by EIS and the apparent Li+ diffusion coefficient in the Li/Na2FePO4F system is evaluated to be as high as 1.152 × 10-11 cm2 s-1. This study demonstrates that the practical and economical synthesis process can be a promising way for industrial production of high performance Na2FePO4F/C electrode material for large-scale lithium ion batteries.

  14. 4f fine-structure levels as the dominant error in the electronic structures of binary lanthanide oxides.

    Science.gov (United States)

    Huang, Bolong

    2016-04-05

    The ground-state 4f fine-structure levels in the intrinsic optical transition gaps between the 2p and 5d orbitals of lanthanide sesquioxides (Ln2 O3 , Ln = La…Lu) were calculated by a two-way crossover search for the U parameters for DFT + U calculations. The original 4f-shell potential perturbation in the linear response method were reformulated within the constraint volume of the given solids. The band structures were also calculated. This method yields nearly constant optical transition gaps between Ln-5d and O-2p orbitals, with magnitudes of 5.3 to 5.5 eV. This result verifies that the error in the band structure calculations for Ln2 O3 is dominated by the inaccuracies in the predicted 4f levels in the 2p-5d transition gaps, which strongly and non-linearly depend on the on-site Hubbard U. The relationship between the 4f occupancies and Hubbard U is non-monotonic and is entirely different from that for materials with 3d or 4d orbitals, such as transition metal oxides. This new linear response DFT + U method can provide a simpler understanding of the electronic structure of Ln2 O3 and enables a quick examination of the electronic structures of lanthanide solids before hybrid functional or GW calculations. © 2015 Wiley Periodicals, Inc.

  15. A novel frameshift mutation of POU4F3 gene associated with autosomal dominant non-syndromic hearing loss

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Hee Keun [Department of Biology, College of Natural Sciences, Kyungpook National University, Daegu (Korea, Republic of); Park, Hong-Joon [Soree Ear Clinic, Seoul (Korea, Republic of); Lee, Kyu-Yup [Vestibulocochlear Research Center, College of Medicine, Wonkwang University, Iksan (Korea, Republic of); Park, Rekil, E-mail: rkpark@wku.ac.kr [Department of Otorhinolaryngology-Head and Neck Surgery, College of Medicine, Kyungpook National University, Daegu (Korea, Republic of); Kim, Un-Kyung, E-mail: kimuk@knu.ac.kr [Department of Biology, College of Natural Sciences, Kyungpook National University, Daegu (Korea, Republic of)

    2010-06-04

    Autosomal dominant mutations in the transcription factor POU4F3 gene are associated with non-syndromic hearing loss in humans; however, there have been few reports of mutations in this gene worldwide. We performed a mutation analysis of the POU4F3 gene in 42 unrelated Koreans with autosomal dominant non-syndromic hearing loss, identifying a novel 14-bp deletion mutation in exon 2 (c.662del14) in one patient. Audiometric examination revealed severe bilateral sensorineural hearing loss in this patient. The novel mutation led to a truncated protein that lacked both functional POU domains. We further investigated the functional distinction between wild-type and mutant POU4F3 proteins using in vitro assays. The wild-type protein was completely localized in the nucleus, while the truncation of protein seriously affected its nuclear localization. In addition, the mutant failed to activate reporter gene expression. This is the first report of a POU4F3 mutation in Asia, and moreover our data suggest that further investigation will need to delineate ethnicity-specific genetic background for autosomal dominant non-syndromic hearing loss within Asian populations.

  16. Atmospheric chemistry of 4:2 fluorotelomer alcohol (n-C4F9CH2CH2OH)

    DEFF Research Database (Denmark)

    Andersen, Mads Peter Sulbæk; Nielsen, Ole John; Hurley, M. D.

    2005-01-01

    Smog chamber/FTIR techniques were used to study the Cl atom initiated oxidation of 4:2 fluorotelomer alcohol (C4F9CH2CH2OH, 4:2 FTOH) in the presence of NOx in 700 Torr of N-2/O-2 diluent at 296 K. Chemical activation effects play an important role in the atmospheric chemistry of the peroxy...

  17. R&D studies of a RICH detector using pressurized C$_{4}$F$_{8}$O radiator gas and a CsI-based gaseous photon detector

    CERN Document Server

    Agócs, A.G; Barnaföldi, G.G; Bellwied, R; Bencédi, G; Bencze, G; Berényi, D; Boldizsár, L; Chattopadhyay, S; Chinellato, D.D; Cindolo, F; Das-Bose, L; Das, D; Das, K; De Cataldo, G; Di Bari, D; Di Mauro, A; Futó, E; Garcia, E; Hamar, G; Harton, A; Jimenez, R.T; Kim, D.W; Kim, J.S; Knospe, A; Kovacs, L; Lévai, P; Markert, C; Martinengo, P; Molnar, L; Nappi, E; Olah, L; Paic, G; Pastore, C; Patino, M.E; Peskov, V; Pinsky, L; Piuz, F; Pochybova, S; Sgura, I; Sinha, T; Song, J; Timmins, A; Van Beelen, J.B; Varga, D; Volpe, G; Weber, M; Xaplanteris, L; Yi, J; Yoo, I.-K

    2013-01-01

    We report on studies of layout and performance of a new Ring Imaging Cherenkov detector using for the fi rst time pressurized C 4 F 8 O radiator gas and a photon detector consisting of a MWPC equipped with a CsI photocathode. In particular, we present here the results of beam tests of a MWPC having an adjustable anode – cathode gap, aiming at the optimization of single photoelectron detection and Cherenkov angle resolution. This system was proposed as a Very High Momentum Particle Identi fi cation (VHMPID) upgrade for the ALICE experiment at LHC to provide charged hadron track-by-track identi fi cation in the momentum range 5 – 25 GeV/c.

  18. R&D studies of a RICH detector using pressurized C4F8O radiator gas and a CsI-based gaseous photon detector

    Science.gov (United States)

    Agócs, A. G.; Barile, F.; Barnaföldi, G. G.; Bellwied, R.; Bencédi, G.; Bencze, G.; Berényi, D.; Boldizsár, L.; Chattopadhyay, S.; Chinellato, D. D.; Cindolo, F.; Das, D.; Das, K.; Das-Bose, L.; De Cataldo, G.; Di Bari, D.; Di Mauro, A.; Futó, E.; Garcia, E.; Hamar, G.; Harton, A.; Jimenez, R. T.; Kim, D. W.; Kim, J. S.; Knospe, A.; Kovacs, L.; Lévai, P.; Markert, C.; Martinengo, P.; Molnar, L.; Nappi, E.; Olah, L.; Paić, G.; Pastore, C.; Patino, M. E.; Peskov, V.; Pinsky, L.; Piuz, F.; Pochybová, S.; Sgura, I.; Sinha, T.; Song, J.; Timmins, A.; Van Beelen, J. B.; Varga, D.; Volpe, G.; Weber, M.; Xaplanteris, L.; Yi, J.; Yoo, I.-K.

    2013-12-01

    We report on studies of layout and performance of a new Ring Imaging Cherenkov detector using for the first time pressurized C4F8O radiator gas and a photon detector consisting of a MWPC equipped with a CsI photocathode. In particular, we present here the results of beam tests of a MWPC having an adjustable anode-cathode gap, aiming at the optimization of single photoelectron detection and Cherenkov angle resolution. This system was proposed as a Very High Momentum Particle Identification (VHMPID) upgrade for the ALICE experiment at LHC to provide charged hadron track-by-track identification in the momentum range 5-25 GeV/c.

  19. The acoustic force density acting on inhomogeneous fluids in acoustic fields

    CERN Document Server

    Karlsen, Jonas T; Bruus, Henrik

    2016-01-01

    We present a theory for the acoustic force density acting on inhomogeneous fluids in acoustic fields on time scales that are slow compared to the acoustic oscillation period. The acoustic force density depends on gradients in the density and compressibility of the fluid. For microfluidic systems, the theory predicts a relocation of the inhomogeneities into stable field-dependent configurations, which are qualitatively different from the horizontally layered configurations due to gravity. Experimental validation is obtained by confocal imaging of aqueous solutions in a glass-silicon microchip.

  20. Synthesis and structural characterization of the hexagonal anti-perovskite Na{sub 2}CaVO{sub 4}F

    Energy Technology Data Exchange (ETDEWEB)

    Green, Robert L., E-mail: rgreen@flpoly.org [Chemistry, Florida Polytechnic University, Lakeland, FL 33805 (United States); Avdeev, Maxim [Australian Science and Technology Organisation, Locked Bag 2001, Kirrawee DC, NSW 2232 (Australia); School of Chemistry, The University of Sydney, Sydney, NSW 2006 (Australia); Vogt, Thomas [NanoCenter and Department of Chemistry and Biochemistry, University of South Carolina, Columbia, SC 29208 (United States)

    2017-06-15

    The structural details of the ordered hexagonal oxyfluoride Na{sub 2}CaVO{sub 4}F prepared by solid-state synthesis using stoichiometric amounts of V{sub 2}O{sub 5}, CaCO{sub 3}, Na{sub 2}CO{sub 3} and NaF were characterized using high-resolution neutron powder diffraction. The structural changes between 25 °C and 750 °C revealed that the two structural subunits in this material behave different when heated: there is an expansion of the face-shared FNa{sub 4}Ca{sub 2} octahedra while the VO{sub 4} tetrahedra due to increased thermal disorder reveal marginal bond contractions. Bond valences and the global instability index point to significant structural disorder at 750 °C. - Graphical abstract: The structure of the novel oxyfluoride Na{sub 2}CaVO{sub 4}F is studied at room temperature and high-temperatures. The structure can be viewed as layers of compression and elongation of polyhedral subunits, which change as a function of temperature. - Highlights: • The novel oxyfluoride, Na{sub 2}CaVO{sub 4}F, is synthesized via solid-state method. • High-resolution neutron diffraction data is used to analyze the structure of Na{sub 2}CaVO{sub 4}F. • Structural subunits exhibit expansion and contraction with increasing temperature. • Higher temperatures increase instability within the structure of Na{sub 2}CaVO{sub 4}F.

  1. Acoustics and Hearing

    CERN Document Server

    Damaske, Peter

    2008-01-01

    When one listens to music at home, one would like to have an acoustic impression close to that of being in the concert hall. Until recently this meant elaborate multi-channelled sound systems with 5 or more speakers. But head-related stereophony achieves the surround-sound effect in living rooms with only two loudspeakers. By virtue of their slight directivity as well as an electronic filter the limitations previously common to two-speaker systems can be overcome and this holds for any arbitrary two-channel recording. The book also investigates the question of how a wide and diffuse sound image can arise in concert halls and shows that the quality of concert halls decisively depends on diffuse sound images arising in the onset of reverberation. For this purpose a strong onset of reverberation is modified in an anechoic chamber by electroacoustic means. Acoustics and Hearing proposes ideas concerning signal processing in the auditory system that explain the measured results and the resultant sound effects plea...

  2. Density-near-zero using the acoustically induced transparency of a Fano acoustic resonator

    KAUST Repository

    Elayouch, A.

    2017-01-05

    We report experimental results of near-zero mass density involving an acoustic metamaterial supporting Fano resonance. For this, we designed and fabricated an acoustic resonator with two closely coupled modes and measured its transmission properties. Our study reveals that the phenomenon of acoustically induced transparency is accompanied by an effect of near-zero density. Indeed, the dynamic effective parameters obtained from experimental data show the presence of a frequency band where the effective mass density is close to zero, with high transmission levels reaching 0.7. Furthermore, we demonstrate that such effective parameters lead to wave guiding in a 90-degrees-bent channel. This kind of acoustic metamaterial can, therefore, give rise to acoustic functions like controlling the wavefront, which may lead to very promising applications in acoustic cloacking or imaging.

  3. Acoustic transducer

    Science.gov (United States)

    Drumheller, Douglas S.

    2000-01-01

    An active acoustic transducer tool for use down-hole applications. The tool includes a single cylindrical mandrel including a shoulder defining the boundary of a narrowed portion over which is placed a sandwich-style piezoelectric tranducer assembly. The piezoelectric transducer assembly is prestressed by being placed in a thermal interference fit between the shoulder of the mandrel and the base of an anvil which is likewise positioned over the narrower portion of the mandrel. In the preferred embodiment, assembly of the tool is accomplished using a hydraulic jack to stretch the mandrel prior to emplacement of the cylindrical sandwich-style piezoelectric transducer assembly and anvil. After those elements are positioned and secured, the stretched mandrel is allowed to return substantially to its original (pre-stretch) dimensions with the result that the piezoelectric transducer elements are compressed between the anvil and the shoulder of the mandrel.

  4. Use of acoustic vortices in acoustic levitation

    DEFF Research Database (Denmark)

    Cutanda Henriquez, Vicente; Santillan, Arturo Orozco; Juhl, Peter Møller

    2009-01-01

    Acoustic fields are known to exert forces on the surfaces of objects. These forces are noticeable if the sound pressure is sufficiently high. Two phenomena where acoustic forces are relevant are: i) acoustic levitation, where strong standing waves can hold small objects at certain positions......, counterbalancing their weight, and ii) acoustic vortices, spinning sound fields that can impinge angular momentum and cause rotation of objects. In this contribution, both force-creating sound fields are studied by means of numerical simulations. The Boundary Element Method is employed to this end. The simulation...... of acoustical vortices uses an efficient numerical implementation based on the superposition of two orthogonal sound fields with a delay of 90° between them. It is shown that acoustic levitation and the use of acoustic vortices can be combined to manipulate objects in an efficient and controlled manner without...

  5. Acoustic telemetry.

    Energy Technology Data Exchange (ETDEWEB)

    Drumheller, Douglas Schaeffer; Kuszmaul, Scott S.

    2003-08-01

    Broadcasting messages through the earth is a daunting task. Indeed, broadcasting a normal telephone conversion through the earth by wireless means is impossible with todays technology. Most of us don't care, but some do. Industries that drill into the earth need wireless communication to broadcast navigation parameters. This allows them to steer their drill bits. They also need information about the natural formation that they are drilling. Measurements of parameters such as pressure, temperature, and gamma radiation levels can tell them if they have found a valuable resource such as a geothermal reservoir or a stratum bearing natural gas. Wireless communication methods are available to the drilling industry. Information is broadcast via either pressure waves in the drilling fluid or electromagnetic waves in the earth and well tubing. Data transmission can only travel one way at rates around a few baud. Given that normal Internet telephone modems operate near 20,000 baud, these data rates are truly very slow. Moreover, communication is often interrupted or permanently blocked by drilling conditions or natural formation properties. Here we describe a tool that communicates with stress waves traveling through the steel drill pipe and production tubing in the well. It's based on an old idea called Acoustic Telemetry. But what we present here is more than an idea. This tool exists, it's drilled several wells, and it works. Currently, it's the first and only acoustic telemetry tool that can withstand the drilling environment. It broadcasts one way over a limited range at much faster rates than existing methods, but we also know how build a system that can communicate both up and down wells of indefinite length.

  6. Acoustic backscatter from turbulent microstructure

    Energy Technology Data Exchange (ETDEWEB)

    Seim, H.E.; Gregg, M.C.; Miyamoto, R.T. [Univ. of Washington, Seattle, WA (United States)

    1995-04-01

    Acoustic backscatter has produced spectacular images of internal ocean processes for nearly two decades, but interpretation of the images remains ambiguous because several mechanisms can generate measurable backscatter. The authors present what is thought to be the first simultaneous measurements of calibrated acoustic returns and turbulent microstructure, collected in a set of 20-m-tall billows. The observations are from Admiralty Inlet, a salt-stratified tidal channel near Puget Sound. Scattering due to turbulent microstructure alone is strong enough to explain the measured backscatter at specific sites within the billows. Existing formulations underestimate the strength of acoustic backscatter from turbulent microstructure. Due to a misinterpretation of the high-wavenumber temperature spectrum, some previous formulations underestimate the differential scattering cross section (sigma) when scattering from the viscous-convective subrange. Also, the influence of salinity on refractive-index fluctuations can be as large as or greater than that of temperature when the density stratification is dominated by salinity. Using temperature alone to estimate sigma in coastal and estuarine waters may lead to significant underestimates. A simple formulation is derived that takes these two factors into account. Because of high ambient scattering from zooplankton in Admiralty Inlet, the acoustic data are conditionally sampled along modeled profiler trajectories to avoid using bulk statistics.

  7. The revised human liver cytochrome P450 "Pie": absolute protein quantification of CYP4F and CYP3A enzymes using targeted quantitative proteomics.

    Science.gov (United States)

    Michaels, Scott; Wang, Michael Zhuo

    2014-08-01

    The CYP4F subfamily of enzymes has been identified recently to be involved in the metabolism of endogenous compounds (arachidonic acid and leukotriene B4), nutrients (vitamins K1 and E), and xenobiotics (pafuramidine and fingolimod). CYP4F2 and CYP4F3B are reported to be expressed in the human liver. However, absolute concentrations of these enzymes in human liver microsomes (HLMs) and their interindividual variability have yet to be determined because of the lack of specific antibodies. Here, an liquid chromatography with tandem mass spectrometry (LC-MS/MS)-based targeted quantitative proteomic approach was employed to determine the absolute protein concentrations of CYP4F2 and CYP4F3B compared with CYP3A in two panels of HLMs (n = 31). As a result, the human hepatic cytochrome P450 (P450) "pie" has been revised to include the contribution of CYP4F enzymes, which amounts to 15% of the total hepatic cytochrome P450 enzymes. CYP4F3B displayed low interindividual variability (3.3-fold) in the HLM panels whereas CYP4F2 displayed large variability (21-fold). However, CYP4F2 variability decreased to 3.4-fold if the two donors with the lowest expression were excluded. In contrast, CYP3A exhibited 29-fold interindividual variability in the same HLM panels. The proposed marker reaction for CYP4F enzymes pafuramidine/DB289 M1 formation did not correlate with CYP4F protein content, suggesting alternate metabolic pathways for DB289 M1 formation in HLMs. In conclusion, CYP4F enzymes are highly expressed in the human liver and their physiologic and pharmacologic roles warrant further investigation. Copyright © 2014 by The American Society for Pharmacology and Experimental Therapeutics.

  8. Novel features in filled skutterudites containing rare-earth elements with a plural number of 4f-electrons

    Energy Technology Data Exchange (ETDEWEB)

    Sato, H., E-mail: sato@phys.mrtro-u.ac.j [Department of Physics, Tokyo Metropolitan University, Tokyo 192-0397 (Japan); Aoki, Y.; Kikuchi, D. [Department of Physics, Tokyo Metropolitan University, Tokyo 192-0397 (Japan); Sugawara, H. [Faculty of Integrated Arts and Science, University of Tokushima, Tokushima 770-8502 (Japan); Higemoto, W.; Ohishi, K.; Ito, T.U.; Heffner, R. [Advanced Science Research Center, Japan Atomic Energy Agency, Tokai, Ibaraki 319-1195 (Japan); Saha, S.R.; Koda, A.; Satoh, K.H.; Nishiyama, K.; Kadono, R. [Institute of Materials Structure Science, High Energy Accelerator Research Organization, Tsukuba, Ibaraki 305-0801 (Japan); Nishida, N. [Department of Physics, Tokyo Institute of Technology, Meguro, Tokyo 152-8551 (Japan); Shu Lei; MacLaughlin, D.E. [Department of Physics and Astronomy, University of California, Riverside, CA 92521 (United States)

    2009-04-15

    Wide varieties of strongly correlated electron phenomena are performed on the stage of a 'filled skutterudite structure'. Especially when one of the players contains a plural number of 4f electrons, the orbital degrees of freedom play a major role as a new type of nonmagnetic and/or weak-magnetic phenomena. Several examples found in Pr- and Sm-based filled skutterudites are introduced in relation to muon spin relaxation (muSR) experiments.

  9. Frequency steerable acoustic transducers

    Science.gov (United States)

    Senesi, Matteo

    Structural health monitoring (SHM) is an active research area devoted to the assessment of the structural integrity of critical components of aerospace, civil and mechanical systems. Guided wave methods have been proposed for SHM of plate-like structures using permanently attached piezoelectric transducers, which generate and sense waves to evaluate the presence of damage. Effective interrogation of structural health is often facilitated by sensors and actuators with the ability to perform electronic, i.e. phased array, scanning. The objective of this research is to design an innovative directional piezoelectric transducer to be employed for the localization of broadband acoustic events, or for the generation of Lamb waves for active interrogation of structural health. The proposed Frequency Steerable Acoustic Transducers (FSATs) are characterized by a spatial arrangement of active material which leads to directional characteristics varying with frequency. Thus FSATs can be employed both for directional sensing and generation of guided waves without relying on phasing and control of a large number of channels. The analytical expression of the shape of the FSATs is obtained through a theoretical formulation for continuously distributed active material as part of a shaped piezoelectric device. The FSAT configurations analyzed in this work are a quadrilateral array and a geometry which corresponds to a spiral in the wavenumber domain. The quadrilateral array is experimentally validated, confirming the concept of frequency-dependent directionality. Its limited directivity is improved by the Wavenumber Spiral FSAT (WS-FSAT), which, instead, is characterized by a continuous frequency dependent directionality. Preliminary validations of the WS-FSAT, using a laser doppler vibrometer, are followed by the implementation of the WS-FSAT as a properly shaped piezo transducer. The prototype is first used for localization of acoustic broadband sources. Signal processing

  10. High-resolution electron spectroscopy of lanthanide (Ce, Pr, and Nd) complexes of cyclooctatetraene: the role of 4f electrons.

    Science.gov (United States)

    Kumari, Sudesh; Roudjane, Mourad; Hewage, Dilrukshi; Liu, Yang; Yang, Dong-Sheng

    2013-04-28

    Cerium, praseodymium, and neodymium complexes of 1,3,5,7-cyclooctatetraene (COT) complexes were produced in a laser-vaporization metal cluster source and studied by pulsed-field ionization zero electron kinetic energy spectroscopy and quantum chemical calculations. The computations included the second-order Møller-Plesset perturbation theory, the coupled cluster method with single, double, and perturbative triple excitations, and the state-average complete active space self-consistent field method. The spectrum of each complex exhibits multiple band systems and is assigned to ionization of several low-energy electronic states of the neutral complex. This observation is different from previous studies of M(COT) (M = Sc, Y, La, and Gd), for which a single band system was observed. The presence of the multiple low-energy electronic states is caused by the splitting of the partially filled lanthanide 4f orbitals in the ligand field, and the number of the low-energy states increases rapidly with increasing number of the metal 4f electrons. On the other hand, the 4f electrons have a small effect on the geometries and vibrational frequencies of these lanthanide complexes.

  11. Optical and electrical study of CdZnTe surfaces passivated by KOH and NH{sub 4}F solutions

    Energy Technology Data Exchange (ETDEWEB)

    Zázvorka, J., E-mail: zazvorka.jakub@gmail.com [Institute of Physics, Faculty of Mathematics and Physics, Charles University in Prague, Ke Karlovu 5, 121 16 Prague (Czech Republic); Franc, J.; Statelov, M.; Pekárek, J.; Veis, M.; Moravec, P. [Institute of Physics, Faculty of Mathematics and Physics, Charles University in Prague, Ke Karlovu 5, 121 16 Prague (Czech Republic); Mašek, K. [Department of Surface and Plasma Science, Faculty of Mathematics and Physics, Charles University in Prague, V Holešovičkách 2, CZ, 18000 Prague (Czech Republic)

    2016-12-15

    Highlights: • Surface of CdZnTe samples was passivated after chemical etching. • KOH and NH{sub 4}F solutions were used as passivation agents. • Growth of surface oxide after passivation is observed. • Surface oxide thickness was evaluated over time after chemical treatment. • Oxidation of the sample correlates with decreased leakage current. - Abstract: Performance of CdZnTe-based detectors is highly related to surface preparation. Mechanical polishing, chemical etching and passivation are routinely employed for this purpose. However, the relation between these processes and the detector performance in terms of underlying physical phenomena has not been fully explained. The dynamics and properties of CdZnTe surface oxide layers, created by passivation with KOH and NH4F/H2O2 solutions, were studied by optical ellipsometry and X-ray photoelectron spectroscopy (XPS). Thicknesses and growth rates of the surface oxide layers differed for each of the passivation methods. Leakage currents which influence the final spectral resolution of the detector were measured simultaneously with ellipsometry. Results of both optical and electrical investigation showed the same trends in the time evolution and correlated to each other. NH4F/H2O2 passivation showed to be a method which produces the most desirable properties of the surface oxide layer.

  12. Responsive acoustic surfaces

    DEFF Research Database (Denmark)

    Peters, Brady; Tamke, Martin; Nielsen, Stig Anton

    2011-01-01

    Acoustic performance is defined by the parameter of reverberation time; however, this does not capture the acoustic experience in some types of open plan spaces. As many working and learning activities now take place in open plan spaces, it is important to be able to understand and design...... for the acoustic conditions of these spaces. This paper describes an experimental research project that studied the design processes necessary to design for sound. A responsive acoustic surface was designed, fabricated and tested. This acoustic surface was designed to create specific sonic effects. The design...... was simulated using custom integrated acoustic software and also using Odeon acoustic analysis software. The research demonstrates a method for designing space- and sound-defining surfaces, defines the concept of acoustic subspace, and suggests some new parameters for defining acoustic subspaces....

  13. Springer Handbook of Acoustics

    CERN Document Server

    Rossing, Thomas D

    2007-01-01

    Acoustics, the science of sound, has developed into a broad interdisciplinary field encompassing the academic disciplines of physics, engineering, psychology, speech, audiology, music, architecture, physiology, neuroscience, and others. The Springer Handbook of Acoustics is an unparalleled modern handbook reflecting this richly interdisciplinary nature edited by one of the acknowledged masters in the field, Thomas Rossing. Researchers and students benefit from the comprehensive contents spanning: animal acoustics including infrasound and ultrasound, environmental noise control, music and human speech and singing, physiological and psychological acoustics, architectural acoustics, physical and engineering acoustics, signal processing, medical acoustics, and ocean acoustics. This handbook reviews the most important areas of acoustics, with emphasis on current research. The authors of the various chapters are all experts in their fields. Each chapter is richly illustrated with figures and tables. The latest rese...

  14. Dual, Hyperfast Spectral Decompositions for Sound Propagation on the Continental Shelf: Acoustic Lensing, Imaging, Communication and ’Seeing’ Inside Shadow Zones

    Science.gov (United States)

    2006-09-30

    wave equation (PE) [ Hardin and Tappert, 1970], well known as one of the most important wave-theoretic, range-dependent propagation models [ Jensen ...5- REFERENCES F. B. Jensen , W. A. Kuperman, M. B. Porter and H. Schmidt, Computation Ocean Acoustics, Springer, 2000. PUBLICATIONS A. R

  15. Acoustic Neurinomas

    Directory of Open Access Journals (Sweden)

    Mohammad Faraji Rad

    2011-01-01

    Full Text Available Acoustic neuromas (AN are schwann cell-derived tumors that commonly arise from the vestibular portion of the eighth cranial nerve also known as vestibular schwannoma(VS causes unilateral hearing loss, tinnitus, vertigo and unsteadiness. In many cases, the tumor size may remain unchanged for many years following diagnosis, which is typically made by MRI. In the majority of cases the tumor is small, leaving the clinician and patient with the options of either serial scanning or active treatment by gamma knife radiosurgery (GKR or microneurosurgery. Despite the vast number of published treatment reports, comparative studies are few. The predominant clinical endpoints of AN treatment include tumor control, facial nerve function and hearing preservation. Less focus has been put on symptom relief and health-related quality of life (QOL. It is uncertain if treating a small tumor leaves the patient with a better chance of obtaining relief from future hearing loss, vertigo or tinnitus than by observing it without treatment.   In this paper we review the literature for the natural course, the treatment alternatives and the results of AN. Finally, we present our experience with a management strategy applied for more than 30 years.

  16. Acoustic Spatiality

    Directory of Open Access Journals (Sweden)

    Brandon LaBelle

    2012-06-01

    Full Text Available Experiences of listening can be appreciated as intensely relational, bringing us into contact with surrounding events, bodies and things. Given that sound propagates and expands outwardly, as a set of oscillations from a particular source, listening carries with it a sensual intensity, whereby auditory phenomena deliver intrusive and disruptive as well as soothing and assuring experiences. The physicality characteristic of sound suggests a deeply impressionistic, locational "knowledge structure" – that is, the ways in which listening affords processes of exchange, of being in the world, and from which we extend ourselves. Sound, as physical energy reflecting and absorbing into the materiality around us, and even one's self, provides a rich platform for understanding place and emplacement. Sound is always already a trace of location.Such features of auditory experience give suggestion for what I may call an acoustical paradigm – how sound sets in motion not only the material world but also the flows of the imagination, lending to forces of signification and social structure, and figuring us in relation to each other. The relationality of sound brings us into a steady web of interferences, each of which announces the promise or problematic of being somewhere.

  17. Optoacoustic endoscopy with optical and acoustic resolution

    Science.gov (United States)

    He, Hailong; Wissmeyer, Georg; Ovsepian, Saak V.; Buehler, Andreas; Ntziachristos, Vasilis

    2017-03-01

    A hybrid optical and acoustic resolution optoacoustic endoscopy is proposed. Laser light is transmitted to tissue by two types of illumination for optical and acoustic resolution imaging respectively. An unfocused ultrasound detector is used for recording optoacoustic signals. The endoscopy probe attains 3.6 mm diameter and is fully encapsulated into a catheter system. We examine the performance of the hybrid endoscope with phantoms and tissue sample, which shows that the hybrid endoscopy can obtain optical resolution in superficial microscopic imaging and ultrasonic tomography reconstruction resolution when imaging at greater depths.

  18. PT-Symmetric Acoustics

    Directory of Open Access Journals (Sweden)

    Xuefeng Zhu

    2014-09-01

    Full Text Available We introduce here the concept of acoustic parity-time (PT symmetry and demonstrate the extraordinary scattering characteristics of the acoustic PT medium. On the basis of exact calculations, we show how an acoustic PT-symmetric medium can become unidirectionally transparent at given frequencies. Combining such a PT-symmetric medium with transformation acoustics, we design two-dimensional symmetric acoustic cloaks that are unidirectionally invisible in a prescribed direction. Our results open new possibilities for designing functional acoustic devices with directional responses.

  19. Acoustic source for generating an acoustic beam

    Science.gov (United States)

    Vu, Cung Khac; Sinha, Dipen N.; Pantea, Cristian

    2016-05-31

    An acoustic source for generating an acoustic beam includes a housing; a plurality of spaced apart piezo-electric layers disposed within the housing; and a non-linear medium filling between the plurality of layers. Each of the plurality of piezoelectric layers is configured to generate an acoustic wave. The non-linear medium and the plurality of piezo-electric material layers have a matching impedance so as to enhance a transmission of the acoustic wave generated by each of plurality of layers through the remaining plurality of layers.

  20. Phase retrieval with background compensation in 4f configuration: advanced augmented Lagrangian technique for amplitude object

    CERN Document Server

    Migukin, Artem; Katkovnik, Vladimir

    2012-01-01

    Generally, wave field reconstructions obtained by phase-retrieval algorithms are noisy, blurred and corrupted by various artifacts such as irregular waves, spots, etc. These disturbances, arising due to many factors such as non-idealities of optical system (misalignment, focusing errors), dust on optical elements, reflections, vibration, are hard to be localized and specified. It is assumed that there is a generalized pupil function at the object plane which describes aberrations in the coherent imaging system manifested at the sensor plane. Here we propose a novel two steps phase-retrieval algorithm to compensate these distortions. We first estimate the cumulative disturbance, called background, using special calibration experiments. Then, we use this background for reconstruction of the object amplitude and phase. The second part of the algorithm is based on the maximum likelihood approach and, in this way, targeted on the optimal amplitude and phase reconstruction from noisy data. Numerical experiments dem...

  1. Holographic acoustic elements for manipulation of levitated objects

    Science.gov (United States)

    Marzo, Asier; Seah, Sue Ann; Drinkwater, Bruce W.; Sahoo, Deepak Ranjan; Long, Benjamin; Subramanian, Sriram

    2015-10-01

    Sound can levitate objects of different sizes and materials through air, water and tissue. This allows us to manipulate cells, liquids, compounds or living things without touching or contaminating them. However, acoustic levitation has required the targets to be enclosed with acoustic elements or had limited manoeuvrability. Here we optimize the phases used to drive an ultrasonic phased array and show that acoustic levitation can be employed to translate, rotate and manipulate particles using even a single-sided emitter. Furthermore, we introduce the holographic acoustic elements framework that permits the rapid generation of traps and provides a bridge between optical and acoustical trapping. Acoustic structures shaped as tweezers, twisters or bottles emerge as the optimum mechanisms for tractor beams or containerless transportation. Single-beam levitation could manipulate particles inside our body for applications in targeted drug delivery or acoustically controlled micro-machines that do not interfere with magnetic resonance imaging.

  2. A family of three-dimensional 3d-4f and 4d-4f heterometallic coordination polymers based on mixed isonicotinate and 2-sulfobenzoate ligands: syntheses, structures and photoluminescent properties.

    Science.gov (United States)

    Li, Xinfa; Huang, Yuanbiao; Cao, Rong

    2012-05-28

    Hydrothermal reactions of isonicotinic acid (Hina), 2-sulfobenzoic acid (H(2)sba), d-block metal salts and lanthanide oxides/hydroxides yielded 17 three-dimensional (3D) 3d-4f and 4d-4f heterometallic coordination polymers (HCPs). They are formulated as [LaAg(sba)(ina)(2)](n) (1), [Ln(2)Ag(2)(sba)(2)(ina)(4)(H(2)O)(2)](n) [Ln = Pr (2), Nd (3), Sm (4), Eu (5), Gd (6), Tb (7), Dy (8), Ho (9), Er (10)] and [Ln(2)Cu(2)(sba)(2)(ina)(4)(H(2)O)(2)](n) [Ln = La (11), Pr (12), Nd (13), Sm (14), Eu (15), Gd (16), Tb (17)]. Their structures were characterized by single crystal X-ray diffraction, powder X-ray diffraction (XRD), infrared (IR) spectroscopy, elemental analysis (EA), and thermogravimetric analysis (TGA). It reveals that they represent two structural types of 3D HCPs. Furthermore, the investigations of their solid-state photoluminescent (PL) property demonstrate the extraordinary emission behaviors. HCP 1(La-Ag) exhibits tunable blue-to-green PL emissions by variation of excitation light. HCPs 6(Gd-Ag), 11(La-Cu), 12(Pr-Cu) and 16(Gd-Cu) show d(10)-metal-based ligand-to-metal charge transfer (LMCT) or metal-to-ligand charge transfer (MLCT) emissions. HCPs 3(Nd-Ag), 4(Sm-Ag), 5(Eu-Ag), 7(Tb-Ag), 8(Dy-Ag), 13(Nd-Cu), 14(Sm-Cu), 15(Eu-Cu) and 17(Tb-Cu) display characteristic PL emissions of the corresponding Ln(III) ions, while both d(10)-metal-based and 4f-metal-centered emissions are observed in the emission spectra of 4(Sm-Ag), 8(Dy-Ag), 14(Sm-Cu) and 17(Tb-Cu).

  3. A4F-SAXS online-coupling for the investigation of nanoparticles and polymers; Die A4F-SAXS Online-Kopplung zur Untersuchung von Nanopartikeln und Polymeren

    Energy Technology Data Exchange (ETDEWEB)

    Knappe, Patrick

    2012-07-13

    In the present thesis the online-coupling of asymmetric flow field-flow fractionation (A4F) with small-angle X-ray scattering (SAXS) as a versatile analytical tool is introduced and applied to current challenges in nanoparticle analysis as well as to model systems of technically relevant polymers. The A4F provides size separation of sample solutions and suspensions. Due to the separation principle only low shear forces are applied which appear in competing methods. Therefore, this method allows processing of very sensitive sample materials. SAXS allows non-destructive probing of nanoscale structures in the range of about one to one hundred nanometers. By coupling with A4F, the complexity of sample systems with broad size distributions, which are therefore frequently hard to characterize, is reduced significantly prior to further analysis. Applying this approach, detailed information about sample properties can be gained accurately with respect to the shape, size and size distribution of particles or conformation of macromolecules in short time. Addition of a dynamic light scattering detector to the setup allows a further conclusion. With the latter, a nanoparticles suspension was characterized rapidly and with good precision with respect to the core properties of the particles as well as the thickness of the stabilizer's shell in a single online run. These parameters are important when dealing not only with functionality but also with the bioavailability or toxicity of nanoparticles. This methodology was also successfully applied to polymer systems for the first time, namely poly(vinyl pyrrolidone)s as well as strong and weak polyelectrolytes. Additionally, due to the applied separation method samples with broad molar mass distributions were processable which otherwise tend to interfere with stationary phase-based chromatography. Furthermore, using SAXS, structural properties can be resolved from smaller polymer size-fractions which are hardly accessible with

  4. Acoustic Imaging Evaluation of Juvenile Salmonid Behavior in the Immediate Forebay of the Water Temperature Control Tower at Cougar Dam, 2010

    Energy Technology Data Exchange (ETDEWEB)

    Khan, Fenton; Johnson, Gary E.; Royer, Ida M.; Phillips, Nathan RJ; Hughes, James S.; Fischer, Eric S.; Ploskey, Gene R.

    2011-10-01

    This report presents the results of an evaluation of juvenile Chinook salmonid (Oncorhynchus tshawytscha) behavior in the immediate forebay of the Water Temperature Control (WTC) tower at Cougar Dam in 2010. The study was conducted by the Pacific Northwest National Laboratory for the U.S. Army Corps of Engineers. The overall goal of the study was to characterize juvenile salmonid behavior and movement patterns in the immediate forebay of the WTC tower for fisheries resource managers to use to make decisions on bioengineering designs for long-term structures and/or operations to facilitate safe downstream passage for juvenile salmonids. We collected acoustic imaging (Dual-Frequency Identification Sonar; DIDSON) data from February 1, 2010 through January 31, 2011 to evaluate juvenile salmonid behavior year-round in the immediate forebay surface layer of the WTC tower (within 20 m, depth 0-5 m). From October 28, 2010 through January 31, 2011 a BlueView acoustic camera was also deployed in an attempt to determine its usefulness for future studies as well as augment the DIDSON data. For the DIDSON data, we processed a total of 35 separate 24-h periods systematically covering every other week in the 12-month study. Two different 24-hour periods were processed for the BlueView data for the feasibility study. Juvenile salmonids were present in the immediate forebay of the WTC tower throughout 2010. The juvenile salmonid abundance index was low in the spring (<200 fish per sample-day), began increasing in late April and peaked in mid-May. Fish abundance index began decreasing in early June and remained low in the summer months. Fish abundance increased again in the fall, starting in October, and peaked on November 8-9. A second peak occurred on December 22. Afterwards, abundance was low for the rest of the study (through January 2011). Average fish length for juvenile salmonids during early spring 2010 was 214 {+-} 86 mm (standard deviation). From May through early November

  5. Acoustic Neuroma Educational Video

    Medline Plus

    Full Text Available ... more... LOGIN CALENDAR DONATE NEWS Home Learn Back Learn about acoustic neuroma AN Facts What is acoustic ... Stories Keywords Shop ANA Discussion Forum About Back Learn more about ANA About ANA Mission, Vision & Values ...

  6. Tethys Acoustic Metadata Database

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Tethys database houses the metadata associated with the acoustic data collection efforts by the Passive Acoustic Group. These metadata include dates, locations...

  7. Acoustic Neuroma Educational Video

    Medline Plus

    Full Text Available ... is acoustic neuroma? Diagnosing Symptoms Side Effects Keywords Questions to ask Choosing a healthcare provider Request a ... What is acoustic neuroma Diagnosing Symptoms Side effects Question To Ask Treatment Options Back Overview Observation Radiation ...

  8. Acoustic Neuroma Educational Video

    Medline Plus

    Full Text Available ... Facts What is acoustic neuroma? Diagnosing Symptoms Side Effects Keywords Questions to ask Choosing a healthcare provider ... Surgery What is acoustic neuroma Diagnosing Symptoms Side effects Question To Ask Treatment Options Back Overview Observation ...

  9. Acoustic Neuroma Educational Video

    Medline Plus

    Full Text Available ... resource Click to learn more... LOGIN CALENDAR DONATE NEWS Home Learn Back Learn about acoustic neuroma AN ... sponsors Become a Sponsor Acoustic Neuroma Association Latest News Join / Renew Login Contact Us Become a Sponsor ...

  10. Atlantic Herring Acoustic Surveys

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The NEFSC Advanced Sampling Technologies Research Group conducts annual fisheries acoustic surveys using state-of-the-art acoustic, midwater trawling, and underwater...

  11. Acoustic Neuroma Educational Video

    Medline Plus

    Full Text Available ... more Click to learn more... LOGIN CALENDAR DONATE NEWS Home Learn Back Learn about acoustic neuroma AN ... a Sponsor Patient Events Acoustic Neuroma Association Latest News Join / Renew Login Contact Us Become a Sponsor ...

  12. AP-4F, antennapedia peptide linked to an amphipathic alpha helical peptide, increases the efficiency of Lipofectamine-mediated gene transfection in endothelial cells.

    Science.gov (United States)

    Ou, Jingsong; Geiger, Tracy; Ou, Zhijun; Ackerman, Allan W; Oldham, Keith T; Pritchard, Kirkwood A

    2003-06-06

    Typically, endothelial cells are difficult to transfect. In this study, we report that antennapedia peptide (AP) linked to L-4F, a water-soluble, amphipathic alpha helical peptide that avidly binds lipids (AP-4F) increases Lipofectamine 2000-mediated transfection of bovine coronary endothelial cell cultures. Transfection efficiency was monitored by flow cytometry and fluorescent microscopy. Lipofectamine 2000 transfection of endothelial cell cultures with green fluorescence protein (GFP)-DNA typically yields transfection efficiencies of 35.4+/-3.3% with low levels of cell death (8.1+/-1.0%). Pre-treatment of the Lipofectamine 2000-GFP-DNA complexes with AP-4F for 5 min increased transfection to 58.2+/-2.8% without increasing cell death. AP-4F increases Lipofectamine 2000-mediated transfection in a time-dependent fashion (within 10-20 min). Systematic studies reveal that the individual components of AP-4F, i.e., AP and L-4F alone, are ineffective in increasing Lipofectamine 2000-mediated transfection and that AP-4F must be directly associated with DNA liposomes prior to transfection for optimal uptake by endothelial cells. These observations demonstrate that AP-4F may be useful for increasing the transfection efficiency of endothelial cell cultures with standard commercially available reagents.

  13. Observation of Marine Animals Using Underwater Acoustic Camera

    Science.gov (United States)

    Iida, Kohji; Takahashi, Rika; Tang, Yong; Mukai, Tohru; Sato, Masanori

    2006-05-01

    An underwater acoustic camera enclosed in a pressure-resistant case was constructed to observe underwater marine animals. This enabled the measurement of the size, shape, and behavior of living marine animals in the detection range up to 240 cm. The transducer array of the acoustic camera was driven by 3.5 MHz ultrasonic signals, and B-mode acoustic images were obtained. Observations were conducted for captive animals in a water tank and for natural animals in a field. The captive animals, including fish, squid and jellyfish, were observed, and a three-dimensional internal structure of animals was reconstructed using multiple acoustical images. The most important contributors of acoustic scattering were the swimbladder and vertebra of bladdered fish, and the liver and reproductive organs of invertebrate animals. In a field experiment, the shape, size, and swimming behavior of wild animals were observed. The possibilities and limitations of the underwater acoustic camera for fishery applications were discussed.

  14. Tutorial on architectural acoustics

    Science.gov (United States)

    Shaw, Neil; Talaske, Rick; Bistafa, Sylvio

    2002-11-01

    This tutorial is intended to provide an overview of current knowledge and practice in architectural acoustics. Topics covered will include basic concepts and history, acoustics of small rooms (small rooms for speech such as classrooms and meeting rooms, music studios, small critical listening spaces such as home theatres) and the acoustics of large rooms (larger assembly halls, auditoria, and performance halls).

  15. Acoustic Neuroma Educational Video

    Medline Plus

    Full Text Available Acoustic Neuroma Association 600 Peachtree Parkway Suite 108 Cumming, GA 30041 770-205-8211 info@ANAUSA.org The world's #1 acoustic ... Shop ANA Leadership & Staff Annual Reports Acoustic Neuroma Association 600 Peachtree Parkway Suite 108 Cumming, GA 30041 ...

  16. Order-disorder phase transition in the antiperovskite-type structure of synthetic kogarkoite, Na3SO4F

    Science.gov (United States)

    Avdontceva, Margarita S.; Zolotarev, Andrey A.; Krivovichev, Sergey V.

    2015-11-01

    High-temperature phase transition of synthetic kogarkoite, Na3SO4F, has been studied by high-temperature X-ray powder and single-crystal diffraction. The temperature of the phase transition can be estimated as 112.5±12.5 °C. The low-temperature phase, α-Na3SO4F, at 293 K, is monoclinic, P21/m, a=18.065(3), b=6.958(1), c=11.446(1) Å, β=107.711(1)°, Z=12. The structure contains thirteen symmetrically independent Na sites with coordination numbers varying from 6 to 8, and six independent S sites. The high-temperature β-phase at 423 K is rhombohedral, R-3m, a=6.94(1), c=24.58(4) Å, Z=9. The crystal structure of both polymorphs of Na3SO4F can be described as a 9R antiperovskite polytype based upon triplets of face-sharing [FNa6] octahedra linked into a three-dimensional framework by sharing corners. In the α-modification, the SO4 tetrahedra are completely ordered and located in the framework cavities. In the β-modification, there are only two symmetrically independent Na atoms in the structure. The main difference between the structures of the α- and β-phases is the degree of ordering of the SO4 tetrahedra: in the α-modification, they are completely ordered, whereas, in the β-modification, the complete disorder is observed, which is manifested in a number of low-occupied O sites around fully occupied S sites. The phase transition is therefore has an order-disorder character and is associated with the decrease of structural complexity measured as an information content per unit cell [577.528 bits for the low- (α) and 154.830 bits for the high- (β) temperature modifications].

  17. The apolipoprotein-AI mimetic peptide L4F at a modest dose does not attenuate weight gain, inflammation, or atherosclerosis in LDLR-null mice.

    Directory of Open Access Journals (Sweden)

    Michelle M Averill

    Full Text Available High density lipoprotein (HDL cholesterol levels are inversely related to cardiovascular disease risk and associated with a reduced risk of type 2 diabetes. Apolipoprotein A-I (apoA-I; major HDL protein mimetics have been reported to reduce atherosclerosis and decrease adiposity. This study investigated the effect of L4F mimetic peptide and apoA-I overexpression on weight gain, insulin resistance, and atherosclerosis in an LDL receptor deficient (Ldlr-/- model fed a high fat high sucrose with cholesterol (HFHSC diet.Studies in differentiated 3T3-L1 adipocytes tested whether L4F could inhibit palmitate-induced adipocyte inflammation. In vivo studies used male Ldlr-/- mice fed a HFHSC diet for 12 weeks and were injected daily with L4F (100 µg/mouse subcutaneously during the last 8 weeks. Wild-type and apoA-I overexpressing Ldlr-/- mice were fed HFHSC diet for 16 weeks.Neither L4F administration nor apoA-I overexpression affected weight gain, total plasma cholesterol or triglycerides in our studies. While pre-treatment of 3T3-L1 adipocytes with either L4F or HDL abolished palmitate-induced cytokine expression in vitro, L4F treatment did not affect circulating or adipose tissue inflammatory markers in vivo. Neither L4F administration nor apoA-I overexpression affected glucose tolerance. ApoA-I overexpression significantly reduced atherosclerotic lesion size, yet L4F treatment did not affect atherosclerosis.Our results suggest that neither L4F (100 µg/day/mouse nor apoA-I overexpression affects adiposity or insulin resistance in this model. We also were unable to confirm a reduction in atherosclerosis with L4F in our particular model. Further studies on the effect of apoA-I mimetics on atherosclerosis and insulin resistance in a variety of dietary contexts are warranted.

  18. Prospecting Lighting Applications with Ligand Field Tools and Density Functional Theory: A First-Principles Account of the 4f(7)-4f(6)5d(1) Luminescence of CsMgBr3:Eu(2+).

    Science.gov (United States)

    Ramanantoanina, Harry; Cimpoesu, Fanica; Göttel, Christian; Sahnoun, Mohammed; Herden, Benjamin; Suta, Markus; Wickleder, Claudia; Urland, Werner; Daul, Claude

    2015-09-08

    The most efficient way to provide domestic lighting nowadays is by light-emitting diodes (LEDs) technology combined with phosphors shifting the blue and UV emission toward a desirable sunlight spectrum. A route in the quest for warm-white light goes toward the discovery and tuning of the lanthanide-based phosphors, a difficult task, in experimental and technical respects. A proper theoretical approach, which is also complicated at the conceptual level and in computing efforts, is however a profitable complement, offering valuable structure-property rationale as a guideline in the search of the best materials. The Eu(2+)-based systems are the prototypes for ideal phosphors, exhibiting a wide range of visible light emission. Using the ligand field concepts in conjunction with density functional theory (DFT), conducted in nonroutine manner, we develop a nonempirical procedure to investigate the 4f(7)-4f(6)5d(1) luminescence of Eu(2+) in the environment of arbitrary ligands, applied here on the CsMgBr3:Eu(2+)-doped material. Providing a salient methodology for the extraction of the relevant ligand field and related parameters from DFT calculations and encompassing the bottleneck of handling large matrices in a model Hamiltonian based on the whole set of 33,462 states, we obtained an excellent match with the experimental spectrum, from first-principles, without any fit or adjustment. This proves that the ligand field density functional theory methodology can be used in the assessment of new materials and rational property design.

  19. [Ru(III)(valen)(CN)2](-): a New Building Block To Design 4d-4f Heterometallic Complexes.

    Science.gov (United States)

    Marinescu, Gabriela; Maxim, Catalin; Clérac, Rodolphe; Andruh, Marius

    2015-06-15

    New 4d-4f heterometallic complexes with a one-dimensional structure, (1)∞[{Ru(valen)(CN)2KRu(valen)(CN)2}{Ln(O2NO)2(CH3OH)3}]·2CH3OH (Ln = Gd, Tb, Dy), have been assembled from the reaction of [K(H2O)2Ru(III)(valen)(CN)2]·H2O with lanthanide nitrates. The exchange interaction between Ru(III) and Gd(III) mediated by the cyanido ligand was determined for the first time and found to be weak and of antiferromagnetic nature.

  20. Acoustic tomography. Laboratory technique Implementation.

    Science.gov (United States)

    Galvis, Jorge; Carvajal, Jenny

    2010-05-01

    From geomechanical tests carried out on rocks it is possible to determine its physico-mechanical properties, which relate the strain and applied stress; even so, conventional tests do not allow to identify how stress is distributed and how it has affected porous media. Today, techniques like acoustic tomography widely used in medicine, geophysics and others sciences, generates images by sections of the interior of a body. Acoustic tomography allows inferring the stress state within porous media; since wave velocities are closely related to media density, if a stress is applied to a rock, it will generate grains compaction and this will be showed by an increase of wave velocity. Implementation was conducted on rock plugs under diverse stress fields, simultaneously recording P-wave velocities (Compressional) on perpendicular planes to sample vertical axis. Transmission and reception of acoustic waves through porous media were done by piezoelectric crystals (PZT) used as sensors. A transmitting crystal excited by a voltage pulse causes a mechanical vibration, which travels across media; this is known as inverse piezoelectric effect. This vibration is recorded by a receiving crystal in which the direct piezoelectric effect appears; which dictates that if a piezoelectric is disturbed mechanically, an electrical signal between its terminals will appear. This electrical signal is used to obtain the wave velocity. Nevertheless, acoustic tomography corresponds to one of those called inverse Problems that arise when from observed data the model parameters must be obtained; in this way, tomography involves iterative reconstruction techniques (ART or SIRT) which are projections of observed data and its later inversion. Obtained results are cross-sectional images of velocity within the rock. In these images it is possible to identify where stress has a greater concentration observing the color map generated; thus, a greater velocity density area corresponding to a greater

  1. Real-time virtual room acoustic simulation

    Science.gov (United States)

    Carneal, James P.; Johnson, Jan; Johnson, Troge; Johnson, Marty

    2003-10-01

    A realistic virtual room acoustic simulation has been implemented on a PC-based computer in near real-time. Room acoustics are calculated by the image source method using realistic absorption coefficients for a variety of realistic surfaces and programmed in MATLAB. The resulting impulse response filters are then applied in near real-time using fast convolution DSP techniques using data being read from a CD-ROM. The system was implemented in a virtual acoustic room facility. Optimizations have been performed to retain the realistic virtual room effect while minimizing computations through limited psycho-acoustic testing. In general, realistic anechoic to reverberant virtual rooms have been re-created with six 8192 coefficient filters. To provide realistic simulations, special care must be taken to accurately reproduce the low frequency acoustics. Since the virtual room acoustic facility was not totally anechoic (as are most anechoic chambers), inverse filters were applied to compensate for over-amplified acoustics at frequencies below 350 Hz.

  2. A sound future for acoustic metamaterials.

    Science.gov (United States)

    Cummer, Steven

    2017-05-01

    The field of acoustic metamaterials borrowed ideas from electromagnetics and optics to create engineered structures that exhibit desired fluid or fluid-like properties for the propagation of sound. These metamaterials offer the possibility of manipulating and controlling sound waves in ways that are challenging or impossible with conventional materials. Metamaterials with zero, or negative, refractive index for sound offer new possibilities for acoustic imaging and for the control of sound at subwavelength scales. The combination of transformation acoustics theory and highly anisotropic acoustic metamaterials enables precise control over the deformation of sound fields, which can be used, for example, to hide or cloak objects from incident acoustic energy. And active acoustic metamaterials use external control and power to create effective material properties that are fundamentally not possible with passive structures. Challenges remain, including the development of efficient techniques for fabricating large-scale metamaterial structures and, critically, converting exciting laboratory experiments into practically useful devices. In this presentation, I will outline the recent history of the field, describe some of the designs and properties of materials with unusual acoustic parameters, discuss examples of extreme manipulation of sound, and finally, provide a personal perspective on future directions in the field.

  3. Acoustic metamaterial design and applications

    Science.gov (United States)

    Zhang, Shu

    The explosion of interest in metamaterials is due to the dramatically increased manipulation ability over light as well as sound waves. This material research was stimulated by the opportunity to develop an artificial media with negative refractive index and the application in superlens which allows super-resolution imaging. High-resolution acoustic imaging techniques are the essential tools for nondestructive testing and medical screening. However, the spatial resolution of the conventional acoustic imaging methods is restricted by the incident wavelength of ultrasound. This is due to the quickly fading evanescent fields which carry the subwavelength features of objects. By focusing the propagating wave and recovering the evanescent field, a flat lens with negative-index can potentially overcome the diffraction limit. We present the first experimental demonstration of focusing ultrasound waves through a flat acoustic metamaterial lens composed of a planar network of subwavelength Helmholtz resonators. We observed a tight focus of half-wavelength in width at 60.5 KHz by imaging a point source. This result is in excellent agreement with the numerical simulation by transmission line model in which we derived the effective mass density and compressibility. This metamaterial lens also displays variable focal length at different frequencies. Our experiment shows the promise of designing compact and light-weight ultrasound imaging elements. Moreover, the concept of metamaterial extends far beyond negative refraction, rather giving enormous choice of material parameters for different applications. One of the most interesting examples these years is the invisible cloak. Such a device is proposed to render the hidden object undetectable under the flow of light or sound, by guiding and controlling the wave path through an engineered space surrounding the object. However, the cloak designed by transformation optics usually calls for a highly anisotropic metamaterial, which

  4. Acoustic Imaging Evaluation of Juvenile Salmonid Behavior in the Immediate Forebay of the Water Temperature Control Tower at Cougar Dam, 2010

    Energy Technology Data Exchange (ETDEWEB)

    Khan, Fenton; Johnson, Gary E.; Royer, Ida M.; Phillips, Nathan RJ; Hughes, James S.; Fischer, Eric S.; Ham, Kenneth D.; Ploskey, Gene R.

    2012-04-01

    This report presents the results of an evaluation of juvenile Chinook salmon (Oncorhynchus tshawytscha) behavior at Cougar Dam on the south fork of the McKenzie River in Oregon in 2010. The study was conducted by the Pacific Northwest National Laboratory for the U.S. Army Corps of Engineers (USACE). The overall goal of the study was to characterize juvenile salmonid behavior and movement patterns in the immediate forebay of the Water Temperature Control (WTC) tower of the dam for USACE and fisheries resource managers use in making decisions about bioengineering designs for long-term structures and/or operations to facilitate safe downstream passage for juvenile salmonids. We collected acoustic imaging (Dual-Frequency Identification Sonar; DIDSON) data from March 1, 2010, through January 31, 2011. Juvenile salmonids (hereafter, called 'fish') were present in the immediate forebay of the WTC tower throughout the study. Fish abundance index was low in early spring (<200 fish per sample-day), increased in late April, and peaked on May 19 (6,039 fish). A second peak was observed on June 6 (2904 fish). Fish abundance index decreased in early June and remained low in the summer months (<100 fish per sample-day). During the fall and winter, fish numbers varied with a peak on November 10 (1881 fish) and a minimum on December 7 (12 fish). A second, smaller, peak occurred on December 22 (607 fish). A univariate statistical analysis indicated fish abundance index (log10-transformed) was significantly (P<0.05) positively correlated with forebay elevation, velocity over the WTC tower intake gate weirs, and river flows into the reservoir. A subsequent multiple regression analysis resulted in a model (R2=0.70) predicting fish abundance (log-transformed index values) using two independent variables of mean forebay elevation and the log10 of the forebay elevation range. From the approximate fish length measurements made using the DIDSON imaging software, the average fish

  5. Design and Synthesis of Thiazolo[5,4-f]quinazolines as DYRK1A Inhibitors, Part II

    Directory of Open Access Journals (Sweden)

    Alicia Foucourt

    2014-09-01

    Full Text Available The convenient synthesis of a focused library (forty molecules of novel 6,6,5-tricyclic thiazolo[5,4-f]quinazolines was realized mainly under microwave irradiation. A novel 6-aminobenzo[d]thiazole-2,7-dicarbonitrile (1 was used as a versatile molecular platform for the synthesis of various derivatives. Kinase inhibition, of the obtained final compounds, was evaluated on a panel of two kinases (DYRK1A/1B together with some known reference DYRK1A and DYRK1B inhibitors (harmine, TG003, NCGC-00189310 and leucettine L41. Compound IC50 values were obtained and compared. Five of the novel thiazolo[5,4-f]quinazoline derivatives prepared, EHT 5372 (8c, EHT 6840 (8h, EHT 1610 (8i, EHT 9851 (8k and EHT 3356 (9b displayed single-digit nanomolar or subnanomolar IC50 values and are among the most potent DYRK1A/1B inhibitors disclosed to date. DYRK1A/1B kinases are known to be involved in the regulation of various molecular pathways associated with oncology, neurodegenerative diseases (such as Alzheimer disease, AD, or other tauopathies, genetic diseases (such as Down Syndrome, DS, as well as diseases involved in abnormal pre-mRNA splicing. The compounds described in this communication constitute a highly potent set of novel molecular probes to evaluate the biology/pharmacology of DYR1A/1B in such diseases.

  6. Design and Synthesis of Thiazolo[5,4-f]quinazolines as DYRK1A Inhibitors, Part I

    Directory of Open Access Journals (Sweden)

    Alicia Foucourt

    2014-09-01

    Full Text Available The convenient synthesis of a library of novel 6,6,5-tricyclic thiazolo[5,4-f] quinazolines (forty molecules was achieved mainly under microwave irradiation. Dimroth rearrangement and 4,5-dichloro-1,2,3,-dithiazolium chloride (Appel salt chemistry were associated for the synthesis of a novel 6-aminobenzo[d]thiazole-2,7-dicarbonitrile (16 a versatile molecular platform for the synthesis of various bioactive derivatives. Kinase inhibition of the final compounds was evaluated on a panel of four Ser/Thr kinases (DYRK1A, CDK5, CK1 and GSK3 chosen for their strong implications in various regulation processes, especially Alzheimer’s disease (AD. In view of the results of this preliminary screening, thiazolo[5,4-f]quinazoline scaffolds constitutes a promising source of inspiration for the synthesis of novel bioactive molecules. Among the compounds of this novel chemolibrary, 7i, 8i and 9i inhibited DYRK1A with IC50 values ranging in the double-digit nanomolar range (40, 47 and 50 nM, respectively.

  7. 3d-4f coupling and multiferroicity in frustrated Cairo Pentagonal oxide DyMn2O5.

    Science.gov (United States)

    Chattopadhyay, S; Petit, S; Ressouche, E; Raymond, S; Balédent, V; Yahia, G; Peng, W; Robert, J; Lepetit, M-B; Greenblatt, M; Foury-Leylekian, P

    2017-11-06

    In solid state science, multifunctional materials and especially multiferroics have attracted a great deal of attention, as they open the possibility for next generation spintronic and data storage devices. Interestingly, while many of them host coexisting 3d and 4f elements, the role of the coupling between these two magnetic entities has remained elusive. By means of single crystal neutron diffraction and inelastic neutron scattering experiments we shed light on this issue in the particular case of the multiferroic oxide DyMn2O5. This compound undergoes a first order magnetic transition from a high temperature incommensurate phase to a low temperature commensurate one. Our investigation reveals that although these two phases have very different magnetic structures, the spin excitations are quite similar indicating a fragile low temperature ground state with respect to the high temperature one. Such a rare scenario is argued to be a manifestation of the competition between the exchange interaction and 4f magnetic anisotropy present in the system. It is concluded that the magnetic structure, hence the ferroelectricity, can be finely tuned depending on the anisotropy of the rare earth.

  8. Acoustic droplet vaporization is initiated by superharmonic focusing

    NARCIS (Netherlands)

    Shpak, O.; Verweij, M.; Vos, H.J.; de Jong, N.; Lohse, Detlef; Versluis, Michel

    2014-01-01

    Acoustically sensitive emulsion droplets composed of a liquid perfluorocarbon have the potential to be a highly efficient system for local drug delivery, embolotherapy, or for tumor imaging. The physical mechanisms underlying the acoustic activation of these phase-change emulsions into a bubbly

  9. Prospects of Passive Element enRiched PhotoAcoustic Computed Tomography (PER-PACT)

    NARCIS (Netherlands)

    Jose, J.

    2012-01-01

    This thesis describes the design and development of a hybrid photoacoustic-ultrasound transmission tomographic imager optimised for small animal imaging (mice). The system allows imaging of ultrasound transmission properties (speed of sound (SOS) and acoustic attenuation (AA) ) simultaneously with

  10. Integrated acoustic-resolution and optical-resolution photoacoustic microscopy using a single multifunctional acoustic lens

    Science.gov (United States)

    Guo, Heng; Xi, Lei

    2016-10-01

    With the rapid development of photoacoustic imaging, it has been widely used in various research fields such as biology, medicine and nanotechnology. Due to the huge difference among photoacoustic imaging systems, it is hard to integrate them in one platform. To solve this problem, we propose to develop a new universal photoacoustic imaging platform that integrates acoustic-resolution photoacoustic microscopy and optical-resolution photoacoustic microscopy through a multifunctional liquid lens. This lens takes advantage of an inherently low acoustic impedance and a tunable focal length that was characterized by the infusion volume of the liquid. In this paper, the liquid lens was used to realize confocal of laser illumination and acoustic detection for both acoustic-resolution and optical-resolution photoacoustic microscopy. The home-made polyvinylidene fluoride (PVDF) acoustic transducer had a center frequency of 10MHz and -6dB frequency spectrum from 4MHz to 15MHz which yielded to an axial resolution of 70 μm. The lateral resolutions of acoustic- and optical-resolution photoacoustic microscopy were evaluated to be 180 μm and 4.8 μm, respectively. The vasculature of rat ears was carried out to evaluate the performance of optical-resolution photoacoustic microscopy.

  11. A new acoustic lens material for large area detectors in photoacoustic breast tomography

    NARCIS (Netherlands)

    Xia, W.; Piras, D.; van Hespen, Johannes C.G.; Steenbergen, Wiendelt; Manohar, Srirang

    2013-01-01

    Objectives We introduce a new acoustic lens material for photoacoustic tomography (PAT) to improve lateral resolution while possessing excellent acoustic acoustic impedance matching with tissue to minimize lens induced image artifacts. Background A large surface area detector due to its high

  12. AST Launch Vehicle Acoustics

    Science.gov (United States)

    Houston, Janice; Counter, D.; Giacomoni, D.

    2015-01-01

    The liftoff phase induces acoustic loading over a broad frequency range for a launch vehicle. These external acoustic environments are then used in the prediction of internal vibration responses of the vehicle and components which result in the qualification levels. Thus, predicting these liftoff acoustic (LOA) environments is critical to the design requirements of any launch vehicle. If there is a significant amount of uncertainty in the predictions or if acoustic mitigation options must be implemented, a subscale acoustic test is a feasible pre-launch test option to verify the LOA environments. The NASA Space Launch System (SLS) program initiated the Scale Model Acoustic Test (SMAT) to verify the predicted SLS LOA environments and to determine the acoustic reduction with an above deck water sound suppression system. The SMAT was conducted at Marshall Space Flight Center and the test article included a 5% scale SLS vehicle model, tower and Mobile Launcher. Acoustic and pressure data were measured by approximately 250 instruments. The SMAT liftoff acoustic results are presented, findings are discussed and a comparison is shown to the Ares I Scale Model Acoustic Test (ASMAT) results.

  13. Synthesis and spectral investigations of Cu(II) ion-doped NaCaAlPO4 F3 phosphor.

    Science.gov (United States)

    Manjari, V Pushpa; Krishna, Ch Rama; Reddy, Ch Venkata; Ravikumar, R V S S N

    2014-12-01

    Cu(II) ion-doped NaCaAlPO(4)F(3) phosphor has been synthesized using a solid state reaction method. The prepared sample is characterized by powder X-ray diffraction, scanning electron microscope, optical absorption, electron paramagnetic resonance photoluminescence and Fourier transform infrared spectroscopy techniques. The crystallite size evaluated from x-ray diffraction data is in nanometers. Scanning electron microscopy micrographs showed the presence of several irregular shaped particles. From optical absorption and electron paramagnetic resonance spectral data the doped Cu(II) ions are ascribed to distorted octahedral site symmetry. The synthesized phosphor exhibits emission bands in ultraviolet, blue and green regions under the excitation wavelength of 335 nm. The CIE chromaticity coordinates (x = 0.159, y = 0.204) also calculated for the prepared sample from the emission spectrum. The Fourier transform infrared spectroscopy spectrum revealed the characteristic vibrational bands of the prepared phosphor material. Copyright © 2014 John Wiley & Sons, Ltd.

  14. Sistema Óptico de Encriptación de Doble Máscara de Fase bajo Arquitectura 4f

    Directory of Open Access Journals (Sweden)

    Carlos A. Ríos

    2010-12-01

    Full Text Available Nowadays the area of optical encryption of information concentrates the efforts of many researchers in laboratories around the world, mainly because contributions presented in the last two decades have shown the reliability, versatility and applicability of such systems. One of the most successful systems, which is currently protected by several patents, is based on the use of two random phase masks and a 4f architecture. In this contribution we do a review of this optical encryption system. We present the theory and the basic procedure explaining the setups and techniques that allow its experimental implementation, andwe present results obtained by computational simulations of the optical virtual system to show the validity of the method.

  15. Images

    Data.gov (United States)

    National Aeronautics and Space Administration — Images for the website main pages and all configurations. The upload and access points for the other images are: Website Template RSW images BSCW Images HIRENASD...

  16. Springer handbook of acoustics

    CERN Document Server

    2014-01-01

    Acoustics, the science of sound, has developed into a broad interdisciplinary field encompassing the academic disciplines of physics, engineering, psychology, speech, audiology, music, architecture, physiology, neuroscience, and electronics. The Springer Handbook of Acoustics is also in his 2nd edition an unparalleled modern handbook reflecting this richly interdisciplinary nature edited by one of the acknowledged masters in the field, Thomas Rossing. Researchers and students benefit from the comprehensive contents. This new edition of the Handbook features over 11 revised and expanded chapters, new illustrations, and 2 new chapters covering microphone arrays  and acoustic emission.  Updated chapters contain the latest research and applications in, e.g. sound propagation in the atmosphere, nonlinear acoustics in fluids, building and concert hall acoustics, signal processing, psychoacoustics, computer music, animal bioacousics, sound intensity, modal acoustics as well as new chapters on microphone arrays an...

  17. Vibro-acoustics

    CERN Document Server

    Nilsson, Anders

    2015-01-01

    This three-volume book gives a thorough and comprehensive presentation of vibration and acoustic theories. Different from traditional textbooks which typically deal with some aspects of either acoustic or vibration problems, it is unique of this book to combine those two correlated subjects together. Moreover, it provides fundamental analysis and mathematical descriptions for several crucial phenomena of Vibro-Acoustics which are quite useful in noise reduction, including how structures are excited, energy flows from an excitation point to a sound radiating surface, and finally how a structure radiates noise to a surrounding fluid. Many measurement results included in the text make the reading interesting and informative. Problems/questions are listed at the end of each chapter and the solutions are provided. This will help the readers to understand the topics of Vibro-Acoustics more deeply. The book should be of interest to anyone interested in sound and vibration, vehicle acoustics, ship acoustics and inter...

  18. Deep Water Ocean Acoustics

    Science.gov (United States)

    2016-08-03

    for including this in acoustic models . Experimental analysis is combined with model development to isolate specific physics and improve our...under- ice scattering, bathymetric diffraction and the application of the ocean acoustic Parabolic Equation to infrasound. 2. Tasks a. Task 1: Basin...of Japan received at the CTBTO HA03 station in Juan Fernandez Chile , are a treasure trove of long-range low frequency acoustic propagation. In

  19. Acoustic shadows help gleaning bats find prey, but may be defeated by prey acoustic camouflage on rough surfaces.

    Science.gov (United States)

    Clare, Elizabeth L; Holderied, Marc W

    2015-09-01

    Perceptual abilities of animals, like echolocating bats, are difficult to study because they challenge our understanding of non-visual senses. We used novel acoustic tomography to convert echoes into visual representations and compare these cues to traditional echo measurements. We provide a new hypothesis for the echo-acoustic basis of prey detection on surfaces. We propose that bats perceive a change in depth profile and an 'acoustic shadow' cast by prey. The shadow is more salient than prey echoes and particularly strong on smooth surfaces. This may explain why bats look for prey on flat surfaces like leaves using scanning behaviour. We propose that rather than forming search images for prey, whose characteristics are unpredictable, predators may look for disruptions to the resting surface (acoustic shadows). The fact that the acoustic shadow is much fainter on rougher resting surfaces provides the first empirical evidence for 'acoustic camouflage' as an anti-predator defence mechanism.

  20. Bioeffects due to acoustic droplet vaporization

    Science.gov (United States)

    Bull, Joseph

    2015-11-01

    Encapsulated micro- and nano-droplets can be vaporized via ultrasound, a process termed acoustic droplet vaporization. Our interest is primarily motivated by a developmental gas embolotherapy technique for cancer treatment. In this methodology, infarction of tumors is induced by selectively formed vascular gas bubbles that arise from the acoustic vaporization of vascular microdroplets. Additionally, the microdroplets may be used as vehicles for localized drug delivery, with or without flow occlusion. In this talk, we examine the dynamics of acoustic droplet vaporization through experiments and theoretical/computational fluid mechanics models, and investigate the bioeffects of acoustic droplet vaporization on endothelial cells and in vivo. Early timescale vaporization events, including phase change, are directly visualized using ultra-high speed imaging, and the influence of acoustic parameters on droplet/bubble dynamics is discussed. Acoustic and fluid mechanics parameters affecting the severity of endothelial cell bioeffects are explored. These findings suggest parameter spaces for which bioeffects may be reduced or enhanced, depending on the objective of the therapy. This work was supported by NIH grant R01EB006476.

  1. Laboratory for Structural Acoustics

    Data.gov (United States)

    Federal Laboratory Consortium — FUNCTION: Supports experimental research where acoustic radiation, scattering, and surface vibration measurements of fluid-loaded and non-fluid-loaded structures are...

  2. Shallow Water Acoustic Laboratory

    Data.gov (United States)

    Federal Laboratory Consortium — FUNCTION: Supports experimental research where high-frequency acoustic scattering and surface vibration measurements of fluid-loaded and non-fluid-loaded structures...

  3. Handbook of Engineering Acoustics

    CERN Document Server

    Möser, Michael

    2013-01-01

    This book examines the physical background of engineering acoustics, focusing on empirically obtained engineering experience as well as on measurement techniques and engineering methods for prognostics. Its goal is not only to describe the state of art of engineering acoustics but also to give practical help to engineers in order to solve acoustic problems. It deals with the origin, the transmission and the methods of the abating different kinds of air-borne and structure-borne sounds caused by various mechanisms – from traffic to machinery and flow-induced sound. In addition the modern aspects of room and building acoustics, as well as psychoacoustics and active noise control, are covered.

  4. Acoustic Technology Laboratory

    Data.gov (United States)

    Federal Laboratory Consortium — This laboratory contains an electro-magnetic worldwide data collection and field measurement capability in the area of acoustic technology. Outfitted by NASA Langley...

  5. A new acoustic lens material for large area detectors in photoacoustic breast tomography

    CERN Document Server

    Xia, Wenfeng; van Hespen, Johan C G; Steenbergen, Wiendelt; Manohar, Srirang

    2013-01-01

    Acoustic lenses made of acrylic plastic (PMMA) have been used to enlarge the acceptance angle of sensitive large surface area detectors and improve lateral resolution. However, PMMA lenses introduce image artifacts due to ultrasound internal reflections within the lenses. In this work we investigated this issue proposing a new lens material Stycast 1090SI. We characterized the acoustic properties of the proposed material in comparison with PMMA. Detector performance using negative lenses with the two materials, was tested using finite element simulation and experiment. Further the image quality of a photoacoustic tomography system was studied using k-Wave simulation and experiment. Our acoustic characterization showed that Stycast 1090SI has tissue-like acoustic impedance, high speed of sound and low acoustic attenuation. Both acoustic lenses show significant enlargement of detector acceptance angle and lateral resolution improvement. However, image artifacts induced by acoustic lenses are reduced using the p...

  6. THE EFFECT OF SINGING TRAINING ON ACOUSTIC PARAMETERS OF VOICE

    Directory of Open Access Journals (Sweden)

    F.Sibel Jagoda

    2016-09-01

    Full Text Available The aim of the present study is to analyze the impact of singing training on the acoustic properties of students’ voices. The participants of the stuy were 20 students between 19 and 32 without absenteeism ranging from the 1st to the 4th grade. The voices of 12 female and 8 male students, enrolled at Selcuk University Dilek Sabancı State Conservatory Opera Main-department, Sub-department of Vocal Arts were recorded throughout 2014-2015 academic year using Shure Sm 48 model microphone in order to determine their acoustic properties using CSL (Computerized Speech Laboratory 4500 to the computer with Kay Elemetrics MDVP (Multi Dimensional Voice Program. In order to determine changes in the acoustic parameters and evaluate the effectiveness of the singing training given, a single sample -pre and post-test research design was used. Hence, among the acoustic properties, F0, (Fundamental Frequency F1, F2, F3, F4, F5, formant frequencies, jitter (%, shimmer (%, NHR (Ratio of harmonic noise parameters were evaluated. The statistical analyses made for the comparison of MDVP parameters before and after the vocal training revealed no statistically significant difference in the students’ F0, Jitter, Shimmer, NHR, F1, F2, F3, and F4 acoustic parameters. However, the F5 formant value revealed statistically significant differences in all the students and a statistically significant difference was seen in the F0 parameter and F5 formant values of female students. Fundamental frequency (F0 is an important parameter changing throughout the singing training process among the female students’ acoustic characteristics. The increase in the F5 formant values of female students and the acoustic properties of all students within normal ranges could be considered as an indicator of the positive impact of the singing training received.

  7. Parametric Room Acoustic Workflows

    DEFF Research Database (Denmark)

    Parigi, Dario; Svidt, Kjeld; Molin, Erik

    2017-01-01

    The paper investigates and assesses different room acoustics software and the opportunities they offer to engage in parametric acoustics workflow and to influence architectural designs. The first step consists in the testing and benchmarking of different tools on the basis of accuracy, speed...

  8. Cochlear bionic acoustic metamaterials

    Science.gov (United States)

    Ma, Fuyin; Wu, Jiu Hui; Huang, Meng; Fu, Gang; Bai, Changan

    2014-11-01

    A design of bionic acoustic metamaterial and acoustic functional devices was proposed by employing the mammalian cochlear as a prototype. First, combined with the experimental data in previous literatures, it is pointed out that the cochlear hair cells and stereocilia cluster are a kind of natural biological acoustic metamaterials with the negative stiffness characteristics. Then, to design the acoustic functional devices conveniently in engineering application, a simplified parametric helical structure was proposed to replace actual irregular cochlea for bionic design, and based on the computational results of such a bionic parametric helical structure, it is suggested that the overall cochlear is a local resonant system with the negative dynamic effective mass characteristics. There are many potential applications in the bandboard energy recovery device, cochlear implant, and acoustic black hole.

  9. Acoustic Signals and Systems

    DEFF Research Database (Denmark)

    2008-01-01

    The Handbook of Signal Processing in Acoustics will compile the techniques and applications of signal processing as they are used in the many varied areas of Acoustics. The Handbook will emphasize the interdisciplinary nature of signal processing in acoustics. Each Section of the Handbook...... will present topics on signal processing which are important in a specific area of acoustics. These will be of interest to specialists in these areas because they will be presented from their technical perspective, rather than a generic engineering approach to signal processing. Non-specialists, or specialists...... from different areas, will find the self-contained chapters accessible and will be interested in the similarities and differences between the approaches and techniques used in different areas of acoustics....

  10. Computational Ocean Acoustics

    CERN Document Server

    Jensen, Finn B; Porter, Michael B; Schmidt, Henrik

    2011-01-01

    Since the mid-1970s, the computer has played an increasingly pivotal role in the field of ocean acoustics. Faster and less expensive than actual ocean experiments, and capable of accommodating the full complexity of the acoustic problem, numerical models are now standard research tools in ocean laboratories. The progress made in computational ocean acoustics over the last thirty years is summed up in this authoritative and innovatively illustrated new text. Written by some of the field's pioneers, all Fellows of the Acoustical Society of America, Computational Ocean Acoustics presents the latest numerical techniques for solving the wave equation in heterogeneous fluid–solid media. The authors discuss various computational schemes in detail, emphasizing the importance of theoretical foundations that lead directly to numerical implementations for real ocean environments. To further clarify the presentation, the fundamental propagation features of the techniques are illustrated in color. Computational Ocean A...

  11. Photoacoustic imaging platforms for multimodal imaging

    Directory of Open Access Journals (Sweden)

    Jeesu Kim

    2015-04-01

    Full Text Available Photoacoustic (PA imaging is a hybrid biomedical imaging method that exploits both acoustical Epub ahead of print and optical properties and can provide both functional and structural information. Therefore, PA imaging can complement other imaging methods, such as ultrasound imaging, fluorescence imaging, optical coherence tomography, and multi-photon microscopy. This article reviews techniques that integrate PA with the above imaging methods and describes their applications.

  12. Acoustic Force Density Acting on Inhomogeneous Fluids in Acoustic Fields

    DEFF Research Database (Denmark)

    Karlsen, Jonas Tobias; Augustsson, Per; Bruus, Henrik

    2016-01-01

    We present a theory for the acoustic force density acting on inhomogeneous fluids in acoustic fields on time scales that are slow compared to the acoustic oscillation period. The acoustic force density depends on gradients in the density and compressibility of the fluid. For microfluidic systems...

  13. Parametric Room Acoustic workflows with real-time acoustic simulation

    DEFF Research Database (Denmark)

    Parigi, Dario

    2017-01-01

    The paper investigates and assesses the opportunities that real-time acoustic simulation offer to engage in parametric acoustics workflow and to influence architectural designs from early design stages......The paper investigates and assesses the opportunities that real-time acoustic simulation offer to engage in parametric acoustics workflow and to influence architectural designs from early design stages...

  14. Epitope-tagging Math5 and Pou4f2: new tools to study retinal ganglion cell development in the mouse.

    Science.gov (United States)

    Fu, Xueyao; Kiyama, Takae; Li, Renzhong; Russell, Mark; Klein, William H; Mu, Xiuqian

    2009-09-01

    Although immunological detection of proteins is used extensively in retinal development, studies are often impeded because antibodies against crucial proteins cannot be generated or are not readily available. Here, we overcome these limitations by constructing genetically engineered alleles for Math5 and Pou4f2, two genes required for retinal ganglion cell (RGC) development. Sequences encoding a peptide epitope from haemagglutinin (HA) were added to Math5 or Pou4f2 in frame to generate Math5(HA) and Pou4f2(HA) alleles. We demonstrate that the tagged alleles recapitulated the wild-type expression patterns of the two genes, and that the tags did not interfere with the function of the cognate proteins. In addition, by co-staining, we found that Math5 and Pou4f2 were transiently co-expressed in newly born RGCs, unequivocally demonstrating that Pou4f2 is immediately downstream of Math5 in RGC formation. The epitope-tagged alleles provide new and useful tools for analyzing gene regulatory networks underlying RGC development.

  15. Superconductivity induced by external pressure in Eu3-x Sr x Bi2S4F4 (x = 1, 2) compounds

    Science.gov (United States)

    Kannan, M.; Kalai Selvan, G.; Haque, Z.; Thakur, Gohil S.; Wang, B.; Ishigaki, K.; Uwatoko, Y.; Gupta, L. C.; Ganguli, A. K.; Arumugam, S.

    2017-11-01

    We have studied the temperature-pressure phase diagram of two materials Eu3-x Sr x Bi2S4F4 (x = 1 and x = 2) by electrical resistivity and magnetic measurements down to 2 K. Semiconducting resistive behavior observed in both the materials under ambient conditions transforms into metallic behavior as externally applied pressure gradually increases. Superconductivity is observed in both the materials at and above applied pressure P = 2.37 GPa. Under the highest pressure P ˜ 2.9 GPa applied in our measurements, T c is ˜9.8 K in Eu2SrBi2S4F4 (x = 1) and 8.2 K in EuSr2Bi2S4F4 (x = 2). Upper critical field H c2(0) ˜ 3.04 T (x = 1) and 1.17 T (x = 2) is estimated from magnetic field dependent resistivity measurements at 2.9 GPa. Using the Arrhenius equation, we estimate the thermally activated flux flow activation energy U 0 as 116 K in Eu2SrBi2S4F4 and 39 K in EuSr2Bi2S4F4. At 2 K, DC magnetic susceptibility measurements indicate S-type paramagnetic behavior.

  16. An Air Coupled Transmission Mode Acoustic Microscope for On-Line Non-Destructive Evaluation

    Science.gov (United States)

    1989-08-01

    Transducers, Imaging, Laminates , Graphite-Epoxy Laminates Acoustic Impedance, Acoustic Microscope 19 ABSTRACT (Continue on reverse if necesary and identify...there is sufficient dynamic range to provide useful images of graphite- epoxy laminates . A material with close to the correct acoustic impedance for...matrix. Microballoons were added to epoxy until the mixture got to the consistency of bread dough . Then this mixture was outgassed and cured. Sample

  17. Investigation into the Effect of Acoustic Radiation Force and Acoustic Streaming on Particle Patterning in Acoustic Standing Wave Fields

    Science.gov (United States)

    Yang, Yanye; Ni, Zhengyang; Guo, Xiasheng; Luo, Linjiao; Tu, Juan; Zhang, Dong

    2017-01-01

    Acoustic standing waves have been widely used in trapping, patterning, and manipulating particles, whereas one barrier remains: the lack of understanding of force conditions on particles which mainly include acoustic radiation force (ARF) and acoustic streaming (AS). In this paper, force conditions on micrometer size polystyrene microspheres in acoustic standing wave fields were investigated. The COMSOL® Mutiphysics particle tracing module was used to numerically simulate force conditions on various particles as a function of time. The velocity of particle movement was experimentally measured using particle imaging velocimetry (PIV). Through experimental and numerical simulation, the functions of ARF and AS in trapping and patterning were analyzed. It is shown that ARF is dominant in trapping and patterning large particles while the impact of AS increases rapidly with decreasing particle size. The combination of using both ARF and AS for medium size particles can obtain different patterns with only using ARF. Findings of the present study will aid the design of acoustic-driven microfluidic devices to increase the diversity of particle patterning. PMID:28753955

  18. Investigation into the Effect of Acoustic Radiation Force and Acoustic Streaming on Particle Patterning in Acoustic Standing Wave Fields

    Directory of Open Access Journals (Sweden)

    Shilei Liu

    2017-07-01

    Full Text Available Acoustic standing waves have been widely used in trapping, patterning, and manipulating particles, whereas one barrier remains: the lack of understanding of force conditions on particles which mainly include acoustic radiation force (ARF and acoustic streaming (AS. In this paper, force conditions on micrometer size polystyrene microspheres in acoustic standing wave fields were investigated. The COMSOL® Mutiphysics particle tracing module was used to numerically simulate force conditions on various particles as a function of time. The velocity of particle movement was experimentally measured using particle imaging velocimetry (PIV. Through experimental and numerical simulation, the functions of ARF and AS in trapping and patterning were analyzed. It is shown that ARF is dominant in trapping and patterning large particles while the impact of AS increases rapidly with decreasing particle size. The combination of using both ARF and AS for medium size particles can obtain different patterns with only using ARF. Findings of the present study will aid the design of acoustic-driven microfluidic devices to increase the diversity of particle patterning.

  19. Translational illusion of acoustic sources by transformation acoustics.

    Science.gov (United States)

    Sun, Fei; Li, Shichao; He, Sailing

    2017-09-01

    An acoustic illusion of creating a translated acoustic source is designed by utilizing transformation acoustics. An acoustic source shifter (ASS) composed of layered acoustic metamaterials is designed to achieve such an illusion. A practical example where the ASS is made with naturally available materials is also given. Numerical simulations verify the performance of the proposed device. The designed ASS may have some applications in, e.g., anti-sonar detection.

  20. Predicting Acoustics in Class Rooms

    DEFF Research Database (Denmark)

    Christensen, Claus Lynge; Rindel, Jens Holger

    2005-01-01

    Typical class rooms have fairly simple geometries, even so room acoustics in this type of room is difficult to predict using today's room acoustic computer modeling software. The reasons why acoustics of class rooms are harder to predict than acoustics of complicated concert halls might...

  1. Experimental observation of temperature and magnetic-field evolution of the 4 f states in CeFe2 revealed by soft x-ray magnetic circular dichroism

    Science.gov (United States)

    Saitoh, Y.; Yasui, A.; Fuchimoto, H.; Nakatani, Y.; Fujiwara, H.; Imada, S.; Narumi, Y.; Kindo, K.; Takahashi, M.; Ebihara, T.; Sekiyama, A.

    2017-07-01

    We revisit the delocalized character of the 4 f states of CeFe2 in the ferromagnetically ordered phase by x-ray magnetic circular dichroism (XMCD) in x-ray absorption spectroscopy (XAS) with improved data quality using single crystals. Surprisingly, the Ce M4 ,5 XMCD spectral shape changes significantly as a function of temperature and applied magnetic field, with no concomitant changes in the spectral shape of the Ce M4 ,5 XAS as well as the Fe L2 ,3 XAS and XMCD. This unusual behavior is characterized by the J =7 /2 states in a 4 f1 configuration mixed into the J =5 /2 ground state. Such extreme sensitivity of the Ce 4 f states to the external perturbations can be related to the magnetic instability toward an antiferromagnetic phase in CeFe2. Our experimental data presented here provide valuable insights into the underlying physics in strongly hybridized ferromagnetic Ce compounds.

  2. Shaping the intensity and degree of coherence of a partially coherent beam by a 4f optical system with an amplitude filter

    Science.gov (United States)

    Wu, Tengfei; Liang, Chunhao; Wang, Fei; Cai, Yangjian

    2017-12-01

    It is known that a 4f optical system with an amplitude filter can be adopted to shape the intensity of a coherent Gaussian beam. In this paper, we investigate the propagation of a typical kind of partially coherent beam called a Gaussian Schell-model (GSM) beam through a 4f optical system with an amplitude filter in the frequency plane. It is demonstrated both numerically and experimentally that the 4f optical system with an amplitude filter can be used to shape the intensity and degree of coherence of a GSM beam simultaneously. The shaped beam displays interesting properties and forms controllable far-field intensity lattices, which may be useful for particle trapping and information transfer.

  3. Imaging Fractures Through Relative Velocity Change Using Ambient Seismic Noise And Distributed Acoustic Sensing (DAS): A SUBTER Pilot Study At Blue Canyon Dome, Socorro NM

    Science.gov (United States)

    James, S. R.; Knox, H. A.; Ajo Franklin, J. B.; Johnson, T. C.; Morris, J.; Grubelich, M. C.; King, D. K.

    2016-12-01

    Knowledge of fracture systems, including locations, morphology, and evolution, is critical for groundwater management, contaminant transport, and energy applications such as reservoir development (i.e. tight shale and geothermal) and reservoir management (i.e. carbon sequestration and wastewater injection). It has long been understood that the presence of fractures reduces bulk seismic velocity, with waves traveling perpendicular to fracture planes experiencing the strongest velocity reduction. We present results from seismic interferometry using ambient seismic noise to detect velocity changes following fracture emplacement from two energetic stimulations. Distributed Acoustic Sensing (DAS) using fiber optic cables was used to record seismic arrivals at high spatial resolution ( 3 ft). Cables were grouted in the annulus of four cased monitoring boreholes surrounding the stimulation borehole at a radius of 4 feet. Ambient noise was recorded before and after each stimulation for 12-hour time periods. We used the Python package MSNoise to compute cross-correlations of all near-horizontal (less than 60°) channel pairs between boreholes and calculated the velocity change of each time period relative to initial conditions prior to stimulation. Results show an average velocity decrease of approximately 6% following the first fracturing event. Variations between channel pairs suggest some are more strongly affected than others, which is supported by evaluation of other geophysical data. These results show promise for locating fractures based on spatial variation in velocity changes. Unsurprisingly, results following the second stimulation are generally more scattered. Some velocities are further reduced compared to those after the first stimulation while others show a relative velocity increase. These results are roughly consistent with time-lapse seismic measurements conducted using active sources and classical sensors (e.g. hydrophones). Sandia National Laboratories is

  4. Acoustic streaming in microchannels

    DEFF Research Database (Denmark)

    Tribler, Peter Muller

    , the acoustic streaming flow, and the forces on suspended microparticles. The work is motivated by the application of particle focusing by acoustic radiation forces in medical, environmental and food sciences. Here acoustic streaming is most often unwanted, because it limits the focusability of particles...... oscillating plates. Furthermore, under general thermodynamic conditions, we derive the time-dependent first- and second-order equations for the conservation of mass, momentum, and energy. The coupling from fluid equations to particle motion is achieved through the expressions for the streaming-induced drag...

  5. Comparative secretome analysis of Trichoderma asperellum S4F8 and Trichoderma reesei Rut C30 during solid-state fermentation on sugarcane bagasse

    Science.gov (United States)

    2013-01-01

    Background The lignocellulosic enzymes of Trichoderma species have received particular attention with regard to biomass conversion to biofuels, but the production cost of these enzymes remains a significant hurdle for their commercial application. In this study, we quantitatively compared the lignocellulolytic enzyme profile of a newly isolated Trichoderma asperellum S4F8 strain with that of Trichoderma reesei Rut C30, cultured on sugarcane bagasse (SCB) using solid-state fermentation (SSF). Results Comparison of the lignocellulolytic enzyme profiles of S4F8 and Rut C30 showed that S4F8 had significantly higher hemicellulase and β-glucosidase enzyme activities. Liquid chromatography tandem mass spectrometry analysis of the two fungal secretomes enabled the detection of 815 proteins in total, with 418 and 397 proteins being specific for S4F8 and Rut C30, respectively, and 174 proteins being common to both strains. In-depth analysis of the associated biological functions and the representation of glycoside hydrolase family members within the two secretomes indicated that the S4F8 secretome contained a higher diversity of main and side chain hemicellulases and β-glucosidases, and an increased abundance of some of these proteins compared with the Rut C30 secretome. Conclusions In SCB SSF, T. asperellum S4F8 produced a more complex lignocellulolytic cocktail, with enhanced hemicellulose and cellobiose hydrolysis potential, compared with T. reesei Rut C30. This bodes well for the development of a more cost-effective and efficient lignocellulolytic enzyme cocktail from T. asperellum for lignocellulosic feedstock hydrolysis. PMID:24286470

  6. Comparative secretome analysis of Trichoderma asperellum S4F8 and Trichoderma reesei Rut C30 during solid-state fermentation on sugarcane bagasse.

    Science.gov (United States)

    Marx, Isa Jacoba; van Wyk, Niël; Smit, Salome; Jacobson, Daniel; Viljoen-Bloom, Marinda; Volschenk, Heinrich

    2013-11-29

    The lignocellulosic enzymes of Trichoderma species have received particular attention with regard to biomass conversion to biofuels, but the production cost of these enzymes remains a significant hurdle for their commercial application. In this study, we quantitatively compared the lignocellulolytic enzyme profile of a newly isolated Trichoderma asperellum S4F8 strain with that of Trichoderma reesei Rut C30, cultured on sugarcane bagasse (SCB) using solid-state fermentation (SSF). Comparison of the lignocellulolytic enzyme profiles of S4F8 and Rut C30 showed that S4F8 had significantly higher hemicellulase and β-glucosidase enzyme activities. Liquid chromatography tandem mass spectrometry analysis of the two fungal secretomes enabled the detection of 815 proteins in total, with 418 and 397 proteins being specific for S4F8 and Rut C30, respectively, and 174 proteins being common to both strains. In-depth analysis of the associated biological functions and the representation of glycoside hydrolase family members within the two secretomes indicated that the S4F8 secretome contained a higher diversity of main and side chain hemicellulases and β-glucosidases, and an increased abundance of some of these proteins compared with the Rut C30 secretome. In SCB SSF, T. asperellum S4F8 produced a more complex lignocellulolytic cocktail, with enhanced hemicellulose and cellobiose hydrolysis potential, compared with T. reesei Rut C30. This bodes well for the development of a more cost-effective and efficient lignocellulolytic enzyme cocktail from T. asperellum for lignocellulosic feedstock hydrolysis.

  7. Three-dimensional Bose-Einstein condensation in the spin-1/2 ferromagnetic-leg ladder 3-Br-4-F-V

    Science.gov (United States)

    Kono, Yohei; Yamaguchi, Hironori; Hosokoshi, Yuko; Sakakibara, Toshiro

    2017-09-01

    The critical exponent of the phase boundary has been examined on the three-dimensional incommensurate ordering phase in the spin-1/2 ferromagnetic-leg ladder 3-Br-4-F-V [=3-(3-bromo-4-fluorophenyl)-1,5-diphenylverdazyl]. Using the temperature-window fitting technique, we obtained the critical exponents which agreed with the three-dimensional (3D) Bose-Einstein condensation (BEC) universality class at both sides of the lower critical field and the saturation field. 3-Br-4-F-V thus becomes a new member of the quantum magnets which prove the universality of the 3D BEC exponent.

  8. Acoustic Neuroma Educational Video

    Medline Plus

    Full Text Available ... Back Learn more about ANA About ANA Mission, Vision & Values Shop ANA Leadership & Staff Annual Reports Acoustic ... 205-8211 info@ANAUSA.org About ANA Mission, Vision & Values Leadership & Staff Annual Reports Shop ANA Home ...

  9. Acoustic Neuroma Educational Video

    Medline Plus

    Full Text Available ... Provider List Member Portal Back Webinar Library Newsletter Library ... About Back Learn more about ANA About ANA Mission, Vision & Values Shop ANA Leadership & Staff Annual Reports Acoustic Neuroma Association 600 Peachtree ...

  10. Acoustic Neuroma Educational Video

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    Full Text Available ... a patient kit Treatment Options Overview Observation Radiation Surgery What is acoustic neuroma Diagnosing Symptoms Side effects ... To Ask Treatment Options Back Overview Observation Radiation Surgery Choosing a healthcare provider Request a patient kit ...

  11. Diagnosing Acoustic Neuroma

    Science.gov (United States)

    ... Values Leadership & Staff Annual Reports Shop ANA Home Learn Diagnosing English English Arabic Catalan Chinese (Simplified) Chinese (Traditional) Danish French German Greek Haitian Creole Hebrew Hindi Italian Japanese Korean Portuguese Romanian Spanish Diagnosing The diagnosis of an acoustic ...

  12. Acoustic Neuroma Educational Video

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    Full Text Available ... Click to learn more... LOGIN CALENDAR DONATE NEWS Home Learn Back Learn about acoustic neuroma AN Facts ... Vision & Values Leadership & Staff Annual Reports Shop ANA Home Learn Educational Video Ronson and Kerri Albany Support ...

  13. Acoustic Neuroma Educational Video

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    Full Text Available ... Click to learn more... LOGIN CALENDAR DONATE NEWS Home Learn Back Learn about acoustic neuroma AN Facts ... Vision & Values Leadership & Staff Annual Reports Shop ANA Home Learn Educational Video Howard of NJ Gloria hiking ...

  14. Acoustic Igniter Project

    Data.gov (United States)

    National Aeronautics and Space Administration — An acoustic igniter eliminates the need to use electrical energy to drive spark systems to initiate combustion in liquid-propellant rockets. It does not involve the...

  15. Acoustic Neuroma Educational Video

    Medline Plus

    Full Text Available ... Choosing a healthcare provider Request a patient kit Treatment Options Overview Observation Radiation Surgery What is acoustic neuroma Diagnosing Symptoms Side effects Question To Ask Treatment Options Back Overview Observation Radiation Surgery Choosing a ...

  16. Acoustic Neuroma Educational Video

    Medline Plus

    Full Text Available ... Mission, Vision & Values Shop ANA Leadership & Staff Annual Reports Acoustic Neuroma Association 600 Peachtree Parkway Suite 108 ... About ANA Mission, Vision & Values Leadership & Staff Annual Reports Shop ANA Home Learn Educational Video English English ...

  17. Acoustics Noise Test Cell

    Data.gov (United States)

    Federal Laboratory Consortium — The Acoustic Noise Test Cell at the NASA/Caltech Jet Propulsion Laboratory (JPL) is located adjacent to the large vibration system; both are located in a class 10K...

  18. Principles of musical acoustics

    CERN Document Server

    Hartmann, William M

    2013-01-01

    Principles of Musical Acoustics focuses on the basic principles in the science and technology of music. Musical examples and specific musical instruments demonstrate the principles. The book begins with a study of vibrations and waves, in that order. These topics constitute the basic physical properties of sound, one of two pillars supporting the science of musical acoustics. The second pillar is the human element, the physiological and psychological aspects of acoustical science. The perceptual topics include loudness, pitch, tone color, and localization of sound. With these two pillars in place, it is possible to go in a variety of directions. The book treats in turn, the topics of room acoustics, audio both analog and digital, broadcasting, and speech. It ends with chapters on the traditional musical instruments, organized by family. The mathematical level of this book assumes that the reader is familiar with elementary algebra. Trigonometric functions, logarithms and powers also appear in the book, but co...

  19. Acoustic Neuroma Educational Video

    Medline Plus

    Full Text Available ... ANA About ANA Mission, Vision & Values Shop ANA Leadership & Staff Annual Reports Acoustic Neuroma Association 600 Peachtree ... info@ANAUSA.org About ANA Mission, Vision & Values Leadership & Staff Annual Reports Shop ANA Home Learn Educational ...

  20. Acoustic Neuroma Educational Video

    Medline Plus

    Full Text Available ... Learn more about ANA About ANA Mission, Vision & Values Shop ANA Leadership & Staff Annual Reports Acoustic Neuroma ... 8211 info@ANAUSA.org About ANA Mission, Vision & Values Leadership & Staff Annual Reports Shop ANA Home Learn ...

  1. Acoustic Neuroma Educational Video

    Medline Plus

    Full Text Available ... Educational Video Scott at the Grand Canyon Proton Center load more hold SHIFT key to load all load all Stay Connected with ANA Newly Diagnosed Living with AN Healthcare Providers Acoustic Neuroma Association Donate Now Newly Diagnosed ...

  2. Acoustic Neuroma Educational Video

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    Full Text Available ... Click to learn more... LOGIN CALENDAR DONATE NEWS Home Learn Back Learn about acoustic neuroma AN Facts ... Vision & Values Leadership & Staff Annual Reports Shop ANA Home Learn Educational Video English English Arabic Catalan Chinese ( ...

  3. Acoustic Neuroma Educational Video

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    Full Text Available ... Click to learn more... LOGIN CALENDAR DONATE NEWS Home Learn Back Learn about acoustic neuroma AN Facts ... Vision & Values Leadership & Staff Annual Reports Shop ANA Home Learn Educational Video Keck Medicine of USC ANWarriors ...

  4. Acoustic Neuroma Educational Video

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    Full Text Available ... Suite 108 Cumming, GA 30041 770-205-8211 info@ANAUSA.org The world's #1 acoustic neuroma resource ... List Member Portal Webinar Library Newsletter Library Patient Info Booklets Member Login Research ANA Survey/Registry AN ...

  5. Acoustic Neuroma Educational Video

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    Full Text Available ... Click to learn more... LOGIN EVENTS DONATE NEWS Home Learn Back Learn about acoustic neuroma AN Facts ... Vision & Values Leadership & Staff Annual Reports Shop ANA Home Learn Educational Video Scott at the Grand Canyon ...

  6. Autonomous Acoustic Receiver System

    Data.gov (United States)

    Federal Laboratory Consortium — FUNCTION: Collects underwater acoustic data and oceanographic data. Data are recorded onboard an ocean buoy and can be telemetered to a remote ship or shore station...

  7. Acoustic ambient noise recorder

    Digital Repository Service at National Institute of Oceanography (India)

    Saran, A.K.; Navelkar, G.S.; Almeida, A.M.; More, S.R.; Chodankar, P.V.; Murty, C.S.

    with a robust outfit that can withstand high pressures and chemically corrosion resistant materials. Keeping these considerations in view, a CMOS micro-controller-based marine acoustic ambient noise recorder has been developed with a real time clock...

  8. Acoustic Neuroma Educational Video

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    Full Text Available ... Request a patient kit Treatment Options Overview Observation Radiation Surgery What is acoustic neuroma Diagnosing Symptoms Side ... Question To Ask Treatment Options Back Overview Observation Radiation Surgery Choosing a healthcare provider Request a patient ...

  9. Thermal Acoustic Fatigue Apparatus

    Data.gov (United States)

    Federal Laboratory Consortium — The Thermal Acoustic Fatigue Apparatus (TAFA) is a progressive wave tube test facility that is used to test structures for dynamic response and sonic fatigue due to...

  10. Acoustic MIMO signal processing

    CERN Document Server

    Huang, Yiteng; Chen, Jingdong

    2006-01-01

    A timely and important book addressing a variety of acoustic signal processing problems under multiple-input multiple-output (MIMO) scenarios. It uniquely investigates these problems within a unified framework offering a novel and penetrating analysis.

  11. Acoustic Neuroma Educational Video

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    Full Text Available ... provider Request a patient kit Treatment Options Overview Observation Radiation Surgery What is acoustic neuroma Diagnosing Symptoms ... effects Question To Ask Treatment Options Back Overview Observation Radiation Surgery Choosing a healthcare provider Request a ...

  12. Acoustic Neuroma Educational Video

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    Full Text Available ... Vision & Values Leadership & Staff Annual Reports Shop ANA ... AN Healthcare Providers Acoustic Neuroma Association Donate Now Newly Diagnosed What is AN? Request a Patient Kit Treatment Options Get Support Find a Provider Discussion Forum Contact ANA Join ...

  13. Anal acoustic reflectometry

    DEFF Research Database (Denmark)

    Mitchell, Peter J; Klarskov, Niels; Telford, Karen J

    2011-01-01

    Anal acoustic reflectometry is a new technique of assessing anal sphincter function. Five new variables reflecting anal canal function are measured: the opening and closing pressure, the opening and closing elastance, and hysteresis.......Anal acoustic reflectometry is a new technique of assessing anal sphincter function. Five new variables reflecting anal canal function are measured: the opening and closing pressure, the opening and closing elastance, and hysteresis....

  14. Deep Water Ocean Acoustics

    Science.gov (United States)

    2016-12-22

    Final Report 3. DATES COVERED (From - To) 7/1/15 to 12/22/16 4. TITLE AND SUBTITLE Deep Water Ocean Acoustics 5a. CONTRACT NUMBER...shortening of the water column); 2.) Explicitly defined the geo-acoustics so that both models had the same sponge ; 3.) Output the complete computational...chosen because this VLA was spaced at /2 at 250Hz and is therefore beamforming capable, covering the conjugate depth. An ambient noise model was

  15. High-temperature order-disorder phase transition in nacaphite, Na2CaPO4F

    Science.gov (United States)

    Avdontceva, Margarita S.; Krzhizhanovskaya, Maria G.; Krivovichev, Sergey V.; Yakovenchuk, Viktor N.

    2015-09-01

    The thermal behavior of nacaphite, Na2CaPO4F, was studied by the powder high-temperature X-ray diffraction method. A monoclinic-to-orthorhombic phase transition has been observed at 330 °C associated with the appearance of the Ca/Na disorder at one of the two crystallographically inequivalent Na sites. At room temperature, nacaphite is monoclinic, P21 /c, a = 13.3185(14), b = 7.0964(8), c = 10.6490(11) Å, β = 113.526(1)°, V = 922.81(17) Å3. The structure is based upon one-dimensional antiperovskite units consisting of face-sharing [FNa4Ca2]7+ anion-centered octahedra running parallel to the c axis. The structure is fully ordered and contains two Ca and four Na sites. The crystal structure of the high-temperature modification [refined by Rietveld method ( R B 0.025) at 400 °C from the powder X-ray diffraction data] is orthorhombic, Pnma, a = 5.4123(1), b = 7.1196(1), c = 12.3171(1) Å, V = 474.62(1) Å3. The structure has one fully occupied Na1 site and one mixed occupied Na2 site, the latter being equally occupied by Na and Ca. The Na1 and Na2 sites are coordinated by two F- and four O2- anions each. The phase transition has an order-disorder character and is associated with the decrease of structural complexity measured as an information content per unit cell (300.235 bits for the low- and 98.117 bits for the high-temperature modifications). Thermal expansion of both modifications has an anisotropic character with the degree of anisotropy increasing from the low- to the high-temperature phase. The direction of the strongest thermal expansion is parallel to the direction of chains of face-sharing anion-centered octahedra that can be explained by the temperature-induced expansion of the F-Na/Ca bonds.

  16. Fracture analysis and determination of in-situ stress direction from resistivity and acoustic image logs and core data in the Wenchuan Earthquake Fault Scientific Drilling Borehole-2 (50-1370 m)

    Science.gov (United States)

    Nie, Xin; Zou, Changchun; Pan, Li; Huang, Zhaohui; Liu, Dongming

    2013-05-01

    After the Wenchuan Earthquake on May 12th, 2008, the Wenchuan Earthquake Fault Scientific Drilling Project (WFSD) was initiated in order to investigate the structure of the fault zones and the mechanism of the earthquake. The WFSD contains four boreholes (WFSD-1, WFSD-2, WFSD-3 and WFSD-4) lying at the maximum displacement locations along the Yingxiu-Beichuan fault zone and the Guanxian-Anxian fault zone, and WFSD-2 is the second borehole and is still being drilled. Core samples, resistivity and acoustic image logging data were acquired from 50 to 1370 m. The natural fractures, borehole breakouts, drilling-induced fractures and drilling-enhanced natural fractures were identified from the cores and the image logs and were statistically analyzed. The strikes of the natural fractures systematically vary and can be sorted into four groups according to depth: (1) above 637 m, mainly striking ENE-WSW; (2) in the interval of 637-932.6 m, striking NNE-SSW; (3) in the interval of 932.6-1200 m, directed ENE-WSW then to WNW-ESE, while striking NE-SW from 1030 m to 1150 m; (4) from 1200 m to 1370 m, maintaining a strike of WNW-ESE. The natural fractures from 50 m to 637 m seem to be reverse faults which strike approximately parallelly to the main fault. Two sets of conjugate fractures around 1002.4 m indicating subvertical maximum principal paleo-stress direction may be a subordinate structure of the main fault caused by a local stress field, and it reveals the complex stress field of Yingxiu-Beichuan fault zone when the fractures formed. A total of 12 BOs, 2 sets of DIFs and one set of DEFs with an overall length of 30.4 m were interpreted from 960 m to 1370 m in WFSD-2. The average SHmax orientation interpreted for WFSD-2 (960-1370 m) is 120.7°-300.7°N (i.e. WNW-ESE) with the standard deviation of 9.2° and it is consistent with the stress status of Yingxiu-Beichuan fault zone which is one of the main fault zones in the 2008 Wenchuan Earthquake. Well logging data and

  17. External validation of the KORA S4/F4 prediction models for the risk of developing type 2 diabetes in older adults : the PREVEND study

    NARCIS (Netherlands)

    Abbasi, Ali; Corpeleijn, Eva; Peelen, Linda M.; Gansevoort, Ronald; de Jong, Paul E.; Gans, Reinold; Rathmann, Wolfgang; Kowall, Bernd; Meisinger, Christine; Hillege, Hans L.; Stolk, Ronald P.; Navis, Gerarda; Beulens, Joline W. J.; Bakker, Stephanus

    Recently, prediction models for type 2 diabetes mellitus (T2DM) in older adults (aged a parts per thousand yen55 year) were developed in the KORA S4/F4 study, Augsburg, Germany. We aimed to externally validate the KORA models in a Dutch population. We used data on both older adults (n = 2,050; aged

  18. 4f-5d Transitions of Tb3+ in Cs2NaYF6: The Effect of Distortion of the Excited-State Configuration

    NARCIS (Netherlands)

    Duan, C.K.; Tanner, P.A.; Meijerink, A.; Makhov, V.

    2011-01-01

    The low-temperature absorption and excitation spectra of interconfigurational 4f–5d transitions of Tb3+ in a cubic fluoride host demonstrate the appearance of a first-order linear Jahn–Teller effect for the high-spin excited states of the excited electronic configuration 4f75d involving 5d t2g

  19. Generation of human iPSC line GRX-MCiPS4F-A2 from adult peripheral blood mononuclear cells (PBMCs with Spanish genetic background

    Directory of Open Access Journals (Sweden)

    Sonia Cabrera

    2015-09-01

    Full Text Available We have generated iPSCs from peripheral blood mononuclear cells (PBMCs of a healthy man using heat sensitive and non-integrative Sendai virus containing Sox2, Oct3/4, c-Myc and Klf4. Human GRX-MCiPS4F-A2 cell line was established and characterized through this study.

  20. Synthesis of carbon-coated Na2MnPO4F hollow spheres as a potential cathode material for Na-ion batteries

    Science.gov (United States)

    Wu, Ling; Hu, Yong; Zhang, Xiaoping; Liu, Jiequn; Zhu, Xing; Zhong, Shengkui

    2018-01-01

    Hollow sphere structure Na2MnPO4F/C composite is synthesized through spray drying, following in-situ pyrolytic carbon coating process. XRD results indicate that the well crystallized composite can be successfully synthesized, and no other impurity phases are detected. SEM and TEM results reveal that the Na2MnPO4F/C samples show intact hollow spherical architecture, and the hollow spherical shells with an average thickness of 150 nm-250 nm are composed of nanosized primary particles. Furthermore, the amorphous carbon layer is uniformly coated on the surface of the hollow sphere, and the nanosized Na2MnPO4F particles are well embedded in the carbon networks. Consequently, the hollow sphere structure Na2MnPO4F/C shows enhanced electrochemical performance. Especially, it is the first time that the obvious potential platforms (∼3.6 V) are observed during the charge and discharge process at room temperature.

  1. Audiometric characteristics of a Dutch family linked to DFNA15 with a novel mutation (p.L289F) in POU4F3.

    NARCIS (Netherlands)

    Pauw, R.J.; Drunen, FJ van; Collin, R.W.J.; Huygen, P.L.; Kremer, H.; Cremers, C.W.R.J.

    2008-01-01

    OBJECTIVE: To report on the audiometric characteristics of a large Dutch family linked to DFNA15 with a novel mutation (p.L289F) in POU4F3 (OMIM 602460). DESIGN: Clinical investigation. SETTING: Tertiary referral center. PATIENTS: Family members from a large 5-generation pedigree with sensorineural

  2. Thermal ionization and thermally activated crossover quenching processes for 5d-4f luminescence in Y3 A l5-x G ax O12 : P r3+

    NARCIS (Netherlands)

    Ueda, J.; Meijerink, Andries; Dorenbos, P.; Bos, A.J.J.; Tanabe, Setsuhisa

    2017-01-01

    We investigated thermally activated ionization and thermally activated crossover as the two possibilities of quenching of 5d luminescence in Pr3+-doped Y3Al5-xGaxO12. Varying the Ga content x gives the control over the relative energy level location of the 5d and 4f2:PJ3 states of Pr3+ and the

  3. Pharmacokinetic modelling of N-(4-[F-18]fluorobenzoyl)interleukin-2 binding to activated lymphocytes in an xenograft model of inflammation

    NARCIS (Netherlands)

    Di Gialleonardo, Valentina; Signore, Alberto; Willemsen, Antoon T. M.; Sijbesma, Jurgen W. A.; Dierckx, Rudi A. J. O.; de Vries, Erik F. J.

    2012-01-01

    N-(4-[F-18]Fluorobenzoyl)interleukin-2 ([F-18]FB-IL2) specifically binds to interleukin-2 receptors (IL-2R) and thus may be used to detect inflammation processes using positron emission tomography (PET). We now validated whether [F-18]FB-IL2 can be used to quantify activated human peripheral blood

  4. Acoustically induced transparency using Fano resonant periodic arrays

    KAUST Repository

    El-Amin, Mohamed

    2015-10-22

    A three-dimensional acoustic device, which supports Fano resonance and induced transparency in its response to an incident sound wave, is designed and fabricated. These effects are generated from the destructive interference of closely coupled one broad- and one narrow-band acoustic modes. The proposed design ensures excitation and interference of two spectrally close modes by locating a small pipe inside a wider and longer one. Indeed, numerical simulations and experiments demonstrate that this simple-to-fabricate structure can be used to generate Fano resonance as well as acoustically induced transparency with promising applications in sensing, cloaking, and imaging.

  5. Safety of MR Imaging at 1.5 T in Fetuses: A Retrospective Case-Control Study of Birth Weights and the Effects of Acoustic Noise.

    Science.gov (United States)

    Strizek, Brigitte; Jani, Jacques C; Mucyo, Eugène; De Keyzer, Frederik; Pauwels, Inge; Ziane, Samir; Mansbach, Anne-Laure; Deltenre, Paul; Cos, Teresa; Cannie, Mieke M

    2015-05-01

    To evaluate the effects of exposure to routine magnetic resonance (MR) imaging at 1.5 T during pregnancy on fetal growth and neonatal hearing function in relation to the dose and timing of in utero exposure in a group of newborns at low risk for congenital hearing impairment or deafness. This retrospective case-control study was approved by the local ethics committee, and written informed consent was waived. Between January 2008 and December 2012, a group of 751 neonates exposed to MR imaging in utero and a group of control subjects comprising 10 042 nonexposed neonates, both groups with no risk factors for hearing impairment at birth, were included. Neonatal hearing screening was performed by means of otoacoustic emission testing and auditory brain stem response according to national guidelines, and the prevalence of hearing impairment in the two groups was compared by using a noninferiority test with Wilson score confidence intervals. The effect of MR exposure on birth weight percentile was examined between the singleton neonates in the exposed group and a randomly chosen subset of 1805 singleton newborns of the nonexposed group by performing an analysis of variance. The rate of hearing impairment or deafness was found to be 0% (0 of 751) in the neonates in the exposed group and was not inferior to that in the nonexposed group (34 of 10 042 [0.34%], P percentiles (50.6% for exposed vs 48.4% for nonexposed; P = .22). This study showed no adverse effects of exposure to 1.5-T MR imaging in utero on neonatal hearing function or birth weight percentiles. (©) RSNA, 2015.

  6. Optical coherence elastography based on high speed imaging of single-hot laser-induced acoustic waves at 16 kHz frame rate

    Science.gov (United States)

    Song, Shaozhen; Hsieh, Bao-Yu; Wei, Wei; Shen, Tueng; Pelivanov, Ivan; O'Donnell, Matthew; Wang, Ruikang K.

    2016-03-01

    Shear wave OCE (SW-OCE) is a novel technique that relies on the detection of the localized shear wave speed to map tissue elasticity. In this study, we demonstrate high speed imaging to capture single-shot transient shear wave propagation for SW-OCE. The fast imaging speed is achieved using a Fourier domain mode-locked (FDML) high-speed swept-source OCT (SS-OCT) system. The frame rate of shear wave imaging is 16 kHz, at an A-line rate of ~1.62 MHz, enabling the detection of high-frequency shear waves up to 8 kHz in bandwidth. Several measures are taken to improve the phase-stability of the SS-OCT system, and the measured displacement sensitivity is ~10 nanometers. To facilitate non-contact elastography, shear waves are generated with the photo-thermal effect using an ultra-violet pulsed laser. High frequency shear waves launched by the pulsed laser contain shorter wavelengths and carry rich localized elasticity information. Benefiting from single-shot acquisition, each SWI scan only takes 2.5 milliseconds, and the reconstruction of the elastogram can be performed in real-time with ~20 Hz refresh rate. SW-OCE measurements are demonstrated on porcine cornea ex vivo. This study is the first demonstration of an all-optical method to perform real-time 3D SW-OCE. It is hoped that this technique will be applicable in the clinic to obtain high-resolution localized quantitative measurements of tissue biomechanical properties.

  7. Low-intensity focused ultrasound (LIFU)-induced acoustic droplet vaporization in phase-transition perfluoropentane nanodroplets modified by folate for ultrasound molecular imaging.

    Science.gov (United States)

    Liu, Jianxin; Shang, Tingting; Wang, Fengjuan; Cao, Yang; Hao, Lan; Ren, JianLi; Ran, Haitao; Wang, Zhigang; Li, Pan; Du, Zhiyu

    2017-01-01

    The commonly used ultrasound (US) molecular probes, such as targeted microbubbles and perfluorocarbon emulsions, present a number of inherent problems including the conflict between US visualization and particle penetration. This study describes the successful fabrication of phase changeable folate-targeted perfluoropentane nanodroplets (termed FA-NDs), a novel US molecular probe for tumor molecular imaging with US. Notably, these FA-NDs can be triggered by low-intensity focused US (LIFU) sonication, providing excellent US enhancement in B-mode and contrast-enhanced US mode in vitro. After intravenous administration into nude mice bearing SKOV3 ovarian carcinomas, 1,1'-dioctadecyl-3,3,3',3' -tetramethylindotricarbocya-nine iodide-labeled FA-NDs were found to accumulate in the tumor region. FA-NDs injection followed by LIFU sonication exhibited remarkable US contrast enhancement in the tumor region. In conclusion, combining our elaborately developed FA-NDs with LIFU sonication provides a potential protocol for US molecular imaging in folate receptor-overexpressing tumors.

  8. Identification of eukaryotic mRNAs that are translated at reduced cap binding complex eIF4F concentrations using a cDNA microarray

    Science.gov (United States)

    Johannes, Gregg; Carter, Mark S.; Eisen, Michael B.; Brown, Patrick O.; Sarnow, Peter

    1999-01-01

    Although most eukaryotic mRNAs need a functional cap binding complex eIF4F for efficient 5′ end- dependent scanning to initiate translation, picornaviral, hepatitis C viral, and a few cellular RNAs have been shown to be translated by internal ribosome entry, a mechanism that can operate in the presence of low levels of functional eIF4F. To identify cellular mRNAs that can be translated when eIF4F is depleted or in low abundance and that, therefore, may contain internal ribosome entry sites, mRNAs that remained associated with polysomes were isolated from human cells after infection with poliovirus and were identified by using a cDNA microarray. Approximately 200 of the 7000 mRNAs analyzed remained associated with polysomes under these conditions. Among the gene products encoded by these polysome-associated mRNAs were immediate-early transcription factors, kinases, and phosphatases of the mitogen-activated protein kinase pathways and several protooncogenes, including c-myc and Pim-1. In addition, the mRNA encoding Cyr61, a secreted factor that can promote angiogenesis and tumor growth, was selectively mobilized into polysomes when eIF4F concentrations were reduced, although its overall abundance changed only slightly. Subsequent tests confirmed the presence of internal ribosome entry sites in the 5′ noncoding regions of both Cyr61 and Pim-1 mRNAs. Overall, this study suggests that diverse mRNAs whose gene products have been implicated in a variety of stress responses, including inflammation, angiogenesis, and the response to serum, can use translational initiation mechanisms that require little or no intact cap binding protein complex eIF4F. PMID:10557283

  9. Genetic Variation of VKORC1 and CYP4F2 Genes Related to Warfarin Maintenance Dose in Patients with Myocardial Infarction

    Directory of Open Access Journals (Sweden)

    Marianne K. Kringen

    2011-01-01

    Full Text Available The aim of this study was to investigate whether the VKORC1*3 (rs7294/9041 G > A, VKORC1*4 (rs17708472/6009 C > T, and CYP4F2 (rs2108622/1347 C > T polymorphisms were associated with elevated warfarin maintenance dose requirements in patients with myocardial infarction (n=105 from the Warfarin Aspirin Reinfarction Study (WARIS-II. We found significant associations between elevated warfarin dose requirements and VKORC1*3 and VKORC1*4 polymorphisms (P=.001 and P=.004, resp., whereas CYP4F2 (1347 C > T showed a weak association on higher warfarin dose requirements (P=.09. However, analysing these variant alleles in a regression analysis together with our previously reported data on VKORC1*2, CYP2C9*2 and CYP2C9*3 polymorphisms, gave no significant associations for neither VKORC1*3, VKORC1*4 nor CYP4F2 (1347 C > T. In conclusion, in patients with myocardial infarction, the individual contribution to warfarin dose requirements from VKORC1*3, VKORC1*4, and CYP4F2 (1347 C > T polymorphisms was negligible. Our results indicate that pharmacogenetic testing for VKORC1*2, CYP2C9*2 and CYP2C9*3 is more informative regarding warfarin dose requirements than testing for VKORC1*3, VKORC1*4, and CYP4F2 (1347 C > T polymorphisms.

  10. Toxicological comparisons of three styles of a commercial U.S. cigarette (Marlboro with the 1R4F reference cigarette.

    Science.gov (United States)

    Patskan, George J; Podraza, Kenneth F; Meurrens, Kris; Coggins, Christopher R E; Friedrichs, Bärbel; Gerstenberg, Birgit; Gomm, Willy; Schnell, Peter; Stabbert, Regina; Veltel, Detlef; Weber, Susanne; Terpstra, Piter

    2008-05-01

    Toxicological comparisons were made of three commercial cigarettes, namely Marlboro full flavor, Marlboro Lights, and Marlboro Ultra Lights, with the 1R4F reference cigarette. The main comparison was a 90-d inhalation study with mainstream smoke at 150 mg total particulate matter per cubic meter, in Sprague-Dawley rats using 6 h/d and 7 d/w exposures. The principal endpoint was histopathology of the respiratory tract, along with examinations of free lung cell counts after broncho-alveolar lavage. Additional studies on mainstream smoke included Salmonella mutagenicity, cytotoxicity of particulate and gas/vapor phases, and analytical chemistry. The exposures produced effectively the same responses in each of the four groups, and the histopathology results in the commercial cigarette groups were also effectively the same. The 1R4F was also tested at 75 and 200 mg/m(3), and most of the histopathology results obtained here showed dose-response relationships. The free lung cell responses were similar in the 1R4F/commercial cigarette comparison, and there were dose-related changes in the 1R4F groups, most notably for neutrophils. Most of the changes produced in the 90-d of exposure were resolved in a 42-d post-inhalation period. Responses in the in vitro and analytical assays for the four cigarettes were in general similar, when data were expressed either per mg TPM or per mg tar yield. There were judged to be no toxicologically meaningful differences between the profiles evaluated at similar smoke concentrations for the three commercial cigarettes and for the 1R4F using these assays.

  11. Translation initiation complex eIF4F is a therapeutic target for dual mTOR kinase inhibitors in non-Hodgkin lymphoma.

    Science.gov (United States)

    Demosthenous, Christos; Han, Jing Jing; Stenson, Mary J; Maurer, Matthew J; Wellik, Linda E; Link, Brian; Hege, Kristen; Dogan, Ahmet; Sotomayor, Eduardo; Witzig, Thomas; Gupta, Mamta

    2015-04-20

    Deregulated mRNA translation has been implicated in disease development and in part is controlled by a eukaryotic initiation complex eIF4F (composed of eIF4E, eIF4G and eIF4A). We demonstrate here that the cap bound fraction from lymphoma cells was enriched with eIF4G and eIF4E indicating that lymphoma cells exist in an activated translational state. Moreover, 77% (110/142) of diffuse large B cell lymphoma tumors expressed eIF4E and this was associated with an inferior event free survival. Over-expression of wild-type eIF4E (eIF4E(WT)) but not cap-mutant eIF4E (eIF4E(cap mutant)) increased the activation of the eIF4F complex. Treatment with the active-site dual mTOR inhibitor CC214-1 reduced the level of the eIF4F complex by decreasing the cap bound fraction of eIF4G and increasing the levels of 4E-BP1. CC214-1 inhibited both the cap dependent and global protein translation. CC214-1 inhibited c-Myc, and cyclin D3 translation by decreasing polysomal fractions from lymphoma cells. Inhibition of eIF4E with shRNA further decreased the CC214-1 induced inhibition of the eIF4F complex, c-Myc, cyclin D3 translation, and colony formation. These studies demonstrate that the eIF4F complex is deregulated in aggressive lymphoma and that dual mTOR therapy has therapeutic potential in these patients.

  12. Measuring acoustic habitats.

    Science.gov (United States)

    Merchant, Nathan D; Fristrup, Kurt M; Johnson, Mark P; Tyack, Peter L; Witt, Matthew J; Blondel, Philippe; Parks, Susan E

    2015-03-01

    1. Many organisms depend on sound for communication, predator/prey detection and navigation. The acoustic environment can therefore play an important role in ecosystem dynamics and evolution. A growing number of studies are documenting acoustic habitats and their influences on animal development, behaviour, physiology and spatial ecology, which has led to increasing demand for passive acoustic monitoring (PAM) expertise in the life sciences. However, as yet, there has been no synthesis of data processing methods for acoustic habitat monitoring, which presents an unnecessary obstacle to would-be PAM analysts. 2. Here, we review the signal processing techniques needed to produce calibrated measurements of terrestrial and aquatic acoustic habitats. We include a supplemental tutorial and template computer codes in matlab and r, which give detailed guidance on how to produce calibrated spectrograms and statistical analyses of sound levels. Key metrics and terminology for the characterisation of biotic, abiotic and anthropogenic sound are covered, and their application to relevant monitoring scenarios is illustrated through example data sets. To inform study design and hardware selection, we also include an up-to-date overview of terrestrial and aquatic PAM instruments. 3. Monitoring of acoustic habitats at large spatiotemporal scales is becoming possible through recent advances in PAM technology. This will enhance our understanding of the role of sound in the spatial ecology of acoustically sensitive species and inform spatial planning to mitigate the rising influence of anthropogenic noise in these ecosystems. As we demonstrate in this work, progress in these areas will depend upon the application of consistent and appropriate PAM methodologies.

  13. Acoustic comfort in eating establishments

    DEFF Research Database (Denmark)

    Svensson, David; Jeong, Cheol-Ho; Brunskog, Jonas

    2014-01-01

    The subjective concept of acoustic comfort in eating establishments has been investigated in this study. The goal was to develop a predictive model for the acoustic comfort, by means of simple objective parameters, while also examining which other subjective acoustic parameters could help explain...... the feeling of acoustic comfort. Through several layers of anal ysis, acoustic comfort was found to be rather complex, and could not be explained entirely by common subjective parameters such as annoyance, intelligibility or privacy. A predictive model for the mean acoustic comfort for an eating establishment...

  14. Interactions in an acoustic world

    CERN Document Server

    Simaciu, Ion; Borsos, Zoltan; Bradac, Mariana

    2016-01-01

    The present paper aims to complete an earlier paper where the acoustic world was introduced. This is accomplished by analyzing the interactions which occur between the inhomogeneities of the acoustic medium, which are induced by the acoustic vibrations traveling in the medium. When a wave packet travels in a medium, the medium becomes inhomogeneous. The spherical wave packet behaves like an acoustic spherical lens for the acoustic plane waves. According to the principle of causality, there is an interaction between the wave and plane wave packet. In specific conditions the wave packet behaves as an acoustic black hole.

  15. Millimeter waves: acoustic and electromagnetic.

    Science.gov (United States)

    Ziskin, Marvin C

    2013-01-01

    This article is the presentation I gave at the D'Arsonval Award Ceremony on June 14, 2011 at the Bioelectromagnetics Society Annual Meeting in Halifax, Nova Scotia. It summarizes my research activities in acoustic and electromagnetic millimeter waves over the past 47 years. My earliest research involved acoustic millimeter waves, with a special interest in diagnostic ultrasound imaging and its safety. For the last 21 years my research expanded to include electromagnetic millimeter waves, with a special interest in the mechanisms underlying millimeter wave therapy. Millimeter wave therapy has been widely used in the former Soviet Union with great reported success for many diseases, but is virtually unknown to Western physicians. I and the very capable members of my laboratory were able to demonstrate that the local exposure of skin to low intensity millimeter waves caused the release of endogenous opioids, and the transport of these agents by blood flow to all parts of the body resulted in pain relief and other beneficial effects. Copyright © 2012 Wiley Periodicals, Inc.

  16. CUDA based Level Set Method for 3D Reconstruction of Fishes from Large Acoustic Data

    DEFF Research Database (Denmark)

    Sharma, Ojaswa; Anton, François

    2009-01-01

    identification is highly desirable for planning sustainable fisheries. Main hurdles in analysing acoustic images are the presence of speckle noise and the vast amount of acoustic data. This paper presents a level set formulation for simultaneous fish reconstruction and noise suppression from raw acoustic images......Acoustic images present views of underwater dynamics, even in high depths. With multi-beam echo sounders (SONARs), it is possible to capture series of 2D high resolution acoustic images. 3D reconstruction of the water column and subsequent estimation of fish abundance and fish species....... Despite the presence of speckle noise blobs, actual fish intensity values can be distinguished by extremely high values, varying exponentially from the background. Edge detection generally gives excessive false edges that are not reliable. Our approach to reconstruction is based on level set evolution...

  17. [Acoustic characteristics of classrooms].

    Science.gov (United States)

    Koszarny, Zbigniew; Chyla, Andrzej

    2003-01-01

    Quality and usefulness of school rooms for transmission of verbal information depends on the two basic parameters: form and quantity of the reverberation time, and profitable line measurements of school rooms from the acoustic point of view. An analysis of the above-mentioned parameters in 48 class rooms and two gymnasiums in schools, which were built in different periods, shows that the most important problem is connected with too long reverberation time and inappropriate acoustic proportions. In schools built in the 1970s, the length of reverberation time is mostly within a low frequency band, while in schools built contemporarily, the maximum length of disappearance time takes place in a quite wide band of 250-2000 Hz. This exceeds optimal values for that kind of rooms at least twice, and five times in the newly built school. A long reverberation time is connected with a low acoustic absorption of school rooms. Moreover, school rooms are characterised by inappropriate acoustic proportions. The classrooms, in their relation to the height, are too long and too wide. It is connected with deterioration of the transmission of verbal information. The data show that this transmission is unequal. Automatically, it leads to a speech disturbance and difficulties with understanding. There is the need for adaptation of school rooms through increase of an acoustic absorption.

  18. Photo-acoustic and video-acoustic methods for sensing distant sound sources

    Science.gov (United States)

    Slater, Dan; Kozacik, Stephen; Kelmelis, Eric

    2017-05-01

    , doing so requires overcoming significant limitations typically including much lower sample rates, reduced sensitivity and dynamic range, more expensive video hardware, and the need for sophisticated video processing. The ATCOM real time image processing software environment provides many of the needed capabilities for researching video-acoustic signal extraction. ATCOM currently is a powerful tool for the visual enhancement of atmospheric turbulence distorted telescopic views. In order to explore the potential of acoustic signal recovery from video imagery we modified ATCOM to extract audio waveforms from the same telescopic video sources. In this paper, we demonstrate and compare both readout techniques for several aerospace test scenarios to better show where each has advantages.

  19. Sea Turtle Acoustic Telemetry Data

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Acoustic transmitters attached to sea turtles captured in various fishing gear enable the animals to be passively tracked. Acoustic receivers set up in an array...

  20. A Century of Acoustic Metrology

    DEFF Research Database (Denmark)

    Rasmussen, Knud

    1998-01-01

    The development in acoustic measurement technique over the last century is reviewed with special emphasis on the metrological aspect.......The development in acoustic measurement technique over the last century is reviewed with special emphasis on the metrological aspect....

  1. Advanced Active Acoustics Lab (AAAL)

    Data.gov (United States)

    Federal Laboratory Consortium — The Advanced Active Acoustics Lab (AAAL) is a state-of-the-art Undersea Warfare (USW) acoustic data analysis facility capable of both active and passive underwater...

  2. Collimator with compensated filtration: clinical adaptation for recommendation 4f of the EU about the radiation protection in oral dental radiology; Colimador con filtracion compensada: adaptacion clinica para alcanzar la recomendacion 4F de la Union Europea sobre proteccion radiologica al paciente en radiologia odontologica

    Energy Technology Data Exchange (ETDEWEB)

    Alcaraz, M.; Garcia-Vera, C.; Bravo, C. La; Morant, J. J.; Armedo, D. Y.; Canteras, M.

    2006-07-01

    Recent recommendations by the European Union (2004) for performing lateral cranial cephalometry (LCC) state that collimation should be maximized so that only those tissues necessary are irradiated when performing clinical diagnoses, although the fact that many manufacturers do not incorporate these elements in their equipment design has been recognised (recommendations 4f). Aim: the manufacture and utilization of a collimator with a pre-patient compensating filter for LLC which may be used in most extraoraldental radiology units, as well as determining the reduction in the dose of radiation absorbed by more sensitive tissues exposed to said clinical exploration. Making use of mannequins, phantom and craniums, we constructed a collimator with a compensating filter and established the necessary technical, dosimetric and quality specifications for its clinical use. Subsequently, we studied 16 patients referred for cephalometric study, determining the radiation dose (TLDs) in both the patients (crystalline lens, frontal lobe, parotid/submaxillary/thyroid glands and brain) and in the radiographic film, as well as in different parts of the collimator/filter. Al presented we are aiming for its clinical use by carrying out LCC in another 16 patients referred of orthodontic treatment but with the pre-a patient introduction of the tested collimator with the compensating filter as a substitute for the usual technique. The collimation reduced the field or radiation by some 40% and with that, so too the radiated tissues. The compensating filter reduced the dose in tissues by some 34.2. Our collimator has allowed the radiological image to be obtained with only one third the usual radiation dose. The dose reaching the film shies only between 17% less than in the usual technique and didn't alter its diagnostic capacity. A reduction of 61,6% of the dose administered to the patient is achieved by incorporating the collimator and filter to most radiological equipment without the

  3. Practical acoustic emission testing

    CERN Document Server

    2016-01-01

    This book is intended for non-destructive testing (NDT) technicians who want to learn practical acoustic emission testing based on level 1 of ISO 9712 (Non-destructive testing – Qualification and certification of personnel) criteria. The essential aspects of ISO/DIS 18436-6 (Condition monitoring and diagnostics of machines – Requirements for training and certification of personnel, Part 6: Acoustic Emission) are explained, and readers can deepen their understanding with the help of practice exercises. This work presents the guiding principles of acoustic emission measurement, signal processing, algorithms for source location, measurement devices, applicability of testing methods, and measurement cases to support not only researchers in this field but also and especially NDT technicians.

  4. Seamount acoustic scattering

    Science.gov (United States)

    Boehlert, George W.

    The cover of the March 1 issue of Eos showed a time series of acoustic scattering above Southeast Hancock Seamount (29°48‧N, 178°05‧E) on July 17-18, 1984. In a comment on that cover Martin Hovland (Eos, August 2, p. 760) argued that gas or “other far reaching causes” may be involved in the observed acoustic signals. He favors a hypothesis that acoustic scattering observed above a seeping pockmark in the North Sea is a combination of bubbles, stable microbubbles, and pelagic organisms and infers that this may be a more general phenomenon and indeed plays a role in the attraction of organisms to seamounts

  5. Acoustics waves and oscillations

    CERN Document Server

    Sen, S.N.

    2013-01-01

    Parameters of acoustics presented in a logical and lucid style Physical principles discussed with mathematical formulations Importance of ultrasonic waves highlighted Dispersion of ultrasonic waves in viscous liquids explained This book presents the theory of waves and oscillations and various applications of acoustics in a logical and simple form. The physical principles have been explained with necessary mathematical formulation and supported by experimental layout wherever possible. Incorporating the classical view point all aspects of acoustic waves and oscillations have been discussed together with detailed elaboration of modern technological applications of sound. A separate chapter on ultrasonics emphasizes the importance of this branch of science in fundamental and applied research. In this edition a new chapter ''Hypersonic Velocity in Viscous Liquids as revealed from Brillouin Spectra'' has been added. The book is expected to present to its readers a comprehensive presentation of the subject matter...

  6. Acoustic and seismic imaging of the Adra Fault (NE Alboran Sea: in search of the source of the 1910 Adra earthquake

    Directory of Open Access Journals (Sweden)

    E. Gràcia

    2012-11-01

    Full Text Available Recently acquired swath-bathymetry data and high-resolution seismic reflection profiles offshore Adra (Almería, Spain reveal the surficial expression of a NW–SE trending 20 km-long fault, which we termed the Adra Fault. Seismic imaging across the structure depicts a sub-vertical fault reaching the seafloor surface and slightly dipping to the NE showing an along-axis structural variability. Our new data suggest normal displacement of the uppermost units with probably a lateral component. Radiocarbon dating of a gravity core located in the area indicates that seafloor sediments are of Holocene age, suggesting present-day tectonic activity. The NE Alboran Sea area is characterized by significant low-magnitude earthquakes and by historical records of moderate magnitude, such as the Mw = 6.1 1910 Adra Earthquake. The location, dimension and kinematics of the Adra Fault agree with the fault solution and magnitude of the 1910 Adra Earthquake, whose moment tensor analysis indicates normal-dextral motion. The fault seismic parameters indicate that the Adra Fault is a potential source of large magnitude (Mw ≤ 6.5 earthquakes, which represents an unreported seismic hazard for the neighbouring coastal areas.

  7. Acoustic Liners for Turbine Engines

    Science.gov (United States)

    Jones, Michael G (Inventor); Grady, Joseph E (Inventor); Kiser, James D. (Inventor); Miller, Christopher (Inventor); Heidmann, James D. (Inventor)

    2016-01-01

    An improved acoustic liner for turbine engines is disclosed. The acoustic liner may include a straight cell section including a plurality of cells with straight chambers. The acoustic liner may also include a bent cell section including one or more cells that are bent to extend chamber length without increasing the overall height of the acoustic liner by the entire chamber length. In some cases, holes are placed between cell chambers in addition to bending the cells, or instead of bending the cells.

  8. Good acoustics central to recovery.

    Science.gov (United States)

    Budd, Richard

    2009-04-01

    Good acoustic conditions in hospitals and other healthcare facilities are known not only to benefit patients by creating an environment that facilitates rest, sleeping, consultation and treatment, but also clinical and nursing staff. At the recent Healthcare Estates conference, Richard Budd of acoustic engineering and noise and vibration consultants Sound Research Laboratories, discussed the revised guidance on good acoustic design in a recently published Health Technical Memorandum, HTM 08-01-Acoustics.

  9. Acoustically Induced Vibration of Structures: Reverberant Vs. Direct Acoustic Testing

    Science.gov (United States)

    Kolaini, Ali R.; O'Connell, Michael R.; Tsoi, Wan B.

    2009-01-01

    Large reverberant chambers have been used for several decades in the aerospace industry to test larger structures such as solar arrays and reflectors to qualify and to detect faults in the design and fabrication of spacecraft and satellites. In the past decade some companies have begun using direct near field acoustic testing, employing speakers, for qualifying larger structures. A limited test data set obtained from recent acoustic tests of the same hardware exposed to both direct and reverberant acoustic field testing has indicated some differences in the resulting structural responses. In reverberant acoustic testing, higher vibration responses were observed at lower frequencies when compared with the direct acoustic testing. In the case of direct near field acoustic testing higher vibration responses appeared to occur at higher frequencies as well. In reverberant chamber testing and direct acoustic testing, standing acoustic modes of the reverberant chamber or the speakers and spacecraft parallel surfaces can strongly couple with the fundamental structural modes of the test hardware. In this paper data from recent acoustic testing of flight hardware, that yielded evidence of acoustic standing wave coupling with structural responses, are discussed in some detail. Convincing evidence of the acoustic standing wave/structural coupling phenomenon will be discussed, citing observations from acoustic testing of a simple aluminum plate. The implications of such acoustic coupling to testing of sensitive flight hardware will be discussed. The results discussed in this paper reveal issues with over or under testing of flight hardware that could pose unanticipated structural and flight qualification issues. Therefore, it is of paramount importance to understand the structural modal coupling with standing acoustic waves that has been observed in both methods of acoustic testing. This study will assist the community to choose an appropriate testing method and test setup in

  10. Acoustic classification of dwellings

    DEFF Research Database (Denmark)

    Berardi, Umberto; Rasmussen, Birgit

    2014-01-01

    insulation performance, national schemes for sound classification of dwellings have been developed in several European countries. These schemes define acoustic classes according to different levels of sound insulation. Due to the lack of coordination among countries, a significant diversity in terms...... of descriptors, number of classes, and class intervals occurred between national schemes. However, a proposal “acoustic classification scheme for dwellings” has been developed recently in the European COST Action TU0901 with 32 member countries. This proposal has been accepted as an ISO work item. This paper...

  11. Beam aperture modifier design with acoustic metasurfaces

    Science.gov (United States)

    Tang, Weipeng; Ren, Chunyu

    2017-10-01

    In this paper, we present a design concept of acoustic beam aperture modifier using two metasurface-based planar lenses. By appropriately designing the phase gradient profile along the metasurface, we obtain a class of acoustic convex lenses and concave lenses, which can focus the incoming plane waves and collimate the converging waves, respectively. On the basis of the high converging and diverging capability of these lenses, two kinds of lens combination scheme, including the convex-concave type and convex-convex type, are proposed to tune up the incoming beam aperture as needed. To be specific, the aperture of the acoustic beam can be shrunk or expanded through adjusting the phase gradient of the pair of lenses and the spacing between them. These lenses and the corresponding aperture modifiers are constructed by the stacking ultrathin labyrinthine structures, which are obtained by the geometry optimization procedure and exhibit high transmission coefficient and a full range of phase shift. The simulation results demonstrate the effectiveness of our proposed beam aperture modifiers. Due to the flexibility in aperture controlling and the simplicity in fabrication, the proposed modifiers have promising potential in applications, such as acoustic imaging, nondestructive evaluation, and communication.

  12. Ultrathin Acoustic Metasurface-Based Schroeder Diffuser

    Directory of Open Access Journals (Sweden)

    Yifan Zhu

    2017-06-01

    Full Text Available “Schroeder diffuser” is a classical design, proposed over 40 years ago, for artificially creating optimal and predictable sound diffuse reflection. It has been widely adopted in architectural acoustics, and it has also shown substantial potential in noise control, ultrasound imaging, microparticle manipulation et al. The conventional Schroeder diffuser, however, has a considerable thickness on the order of one wavelength, severely impeding its applications for low-frequency sound. In this paper, a new class of ultrathin and planar Schroeder diffusers are proposed based on the concept of an acoustic metasurface. Both numerical and experimental results demonstrate satisfactory sound diffuse reflection produced from the metasurface-based Schroeder diffuser despite it being approximately 1 order of magnitude thinner than the conventional one. The proposed design not only offers promising building blocks with great potential to profoundly impact architectural acoustics and related fields, but it also constitutes a major step towards real-world applications of acoustic metasurfaces.

  13. The diagnostic performances of conventional strain elastography (SE), acoustic radiation force impulse (ARFI) imaging and point shear-wave speed (pSWS) measurement for non-calcified thyroid nodules.

    Science.gov (United States)

    Chen, Bao-Ding; Xu, Hui-Xiong; Zhang, Yi-Feng; Liu, Bo-Ji; Guo, Le-Hang; Li, Dan-Dan; Zhao, Chong-Ke; Li, Xiao-Long; Wang, Dan; Zhao, Shuang-Shuang

    2017-01-01

    Non-calcified thyroid nodules are relatively difficult to diagnose only relying on features of at conventional US images. To investigate the diagnostic performances of conventional strain elastography (SE), acoustic radiation force impulse (ARFI) SE and point shear-wave speed (pSWS) measurement for non-calcified thyroid nodules. A total of 201 non-calcified thyroid nodules in 195 patients were studied. They were examined with conventional ultrasound (US), conventional SE, ARFI SE and pSWS measurement. Their diagnostic performances and multivariable models were assessed with receiver operating characteristic (ROC) curve and logistic regression analyses respectively. There were 156 benign and 45 malignant non-calcified nodules proven by histopathology or cystology. The mean diameters of the nodules were 21.2±10.8 mm. Areas under receiver operating characteristic curve (AUCs) of elastography features (ranged, 0.488-0.745) were all greater than that of US (ranged, 0.111-0.332). At multivariate analysis, there were three predictors of malignancy for non-calcified nodules, including pSWS of nodule (odds ratio [OR], 34.960; 95% CI, 11.582-105.529), marked hypoechogenicity (OR, 16.223; 95% CI, 1.761-149.454) and ARFI SE grade (OR, 10.900; 95% CI, 3.567-33.310). US+SE+pSWS owned the largest AUC (0.936; 95% CI, 0.887-0.985; P < 0.05), followed by US+pSWS (0.889; 95% CI, 0.823-0.955), and the poorest was US (0.727; 95% CI, 0.635-0.819). ARFI SE and pSWS measurement had better diagnostic performances than conventional SE and US. When US combined with SE and pSWS measurement, it could achieve an excellent diagnostic performance and might contribute a better decision-making of FNA for non-calcified thyroid nodules.

  14. Carbon Nanotube Underwater Acoustic Thermophone

    Science.gov (United States)

    2016-09-23

    material (such as a piezoelectric ceramic , piezocomposite, or a magnetostrictive ferromagnetic compound). This electrical excitation creates a...Traditional acoustic transduction typically begins with the generation of electrical excitation pulsed through an amplifier into an electro-acoustic...mechanical vibration that is then converted into an acoustic wave to produce sound. The lower the preferred transmitting frequency (and hence a longer

  15. Inspection of copper canister for spent nuclear fuel by means of ultrasound. Copper characterization, FSW monitoring with acoustic emission and ultrasonic imaging

    Energy Technology Data Exchange (ETDEWEB)

    Stepinski, Tadeusz (ed.); Engholm, Marcus; Olofsson, Tomas (Uppsala Univ., Signals and Systems, Dept. of Technical Sciences, Uppsala (Sweden))

    2009-08-15

    This report contains the research results concerning advanced ultrasound for the inspection of copper canisters for spent nuclear fuel obtained at Signals and Systems, Uppsala University in 2008. The first part of the report is concerned with aspects related to ultrasonic attenuation of copper material used for canisters. We present results of attenuation measurement performed for a number of samples taken from a real canister; two from the lid and four from different parts of canister wall. Ultrasonic attenuation of the material originating from canister lid is relatively low (less that 50 dB/m) and essentially frequency independent in the frequency range up to 5 MHz. However, for the material originating from the extruded canister part considerable variations of the attenuation are observed, which can reach even 200 dB/m at 3.5 MHz. In the second part of the report we present further development of the concept of the friction stir welding process monitoring by means of multiple sensors formed into a uniform circular array (UCA). After a brief introduction into modeling Lamb waves and UCA we focus on array processing techniques that enable estimating direction of arrival of multimodal Lamb waves. We consider two new techniques, the Capon beamformer and the broadband multiple signal classification technique (MUSIC). We present simulation results illustrating their performance. In the final part we present the phase shift migration algorithm for ultrasonic imaging of layered media using synthetic aperture concept. We start from explaining theory of the phase migration concept, which is followed by the results of experiments performed on copper blocks with drilled holes. We show that the proposed algorithm performs well for immersion inspection of metal objects and yields both improved spatial resolution and suppressed grain noise

  16. Fundamentals of Acoustics. Psychoacoustics and Hearing. Acoustical Measurements

    Science.gov (United States)

    Begault, Durand R.; Ahumada, Al (Technical Monitor)

    1997-01-01

    These are 3 chapters that will appear in a book titled "Building Acoustical Design", edited by Charles Salter. They are designed to introduce the reader to fundamental concepts of acoustics, particularly as they relate to the built environment. "Fundamentals of Acoustics" reviews basic concepts of sound waveform frequency, pressure, and phase. "Psychoacoustics and Hearing" discusses the human interpretation sound pressure as loudness, particularly as a function of frequency. "Acoustic Measurements" gives a simple overview of the time and frequency weightings for sound pressure measurements that are used in acoustical work.

  17. First-principles study on surface properties of t-LiFeSO4F: Showing a potential way to enhance electronic conductivity

    Science.gov (United States)

    Xie, Weina; Yang, Xiaoling; Lin, Yanyun; Zhuang, Weiling; Luo, Qiong

    2017-09-01

    Systematic theoretical investigation on the surface properties of t-LiFeSO4F based on the stoichiometric (1 0 0), (0 1 0), and (0 0 1) surfaces at the lowest energy termination has been performed within the GGA+U framework. The surface energies of (1 0 0), (0 1 0), and (0 0 1) surfaces are 1.10, 1.64 and 1.04 J/m2 respectively. The (1 0 0) and (0 1 0) surfaces are charge transfer insulators with band gaps of 2.92 and 1.95 eV, respectively. The predicted (0 0 1) surface exhibits metallic-like character. This study suggests that increasing the percentage of (0 0 1) surface on t-LiFeSO4F crystals is an effective solution to enhance its electronic conductivity.

  18. Validation and application of Acoustic Mapping Velocimetry

    Science.gov (United States)

    Baranya, Sandor; Muste, Marian

    2016-04-01

    The goal of this paper is to introduce a novel methodology to estimate bedload transport in rivers based on an improved bedform tracking procedure. The measurement technique combines components and processing protocols from two contemporary nonintrusive instruments: acoustic and image-based. The bedform mapping is conducted with acoustic surveys while the estimation of the velocity of the bedforms is obtained with processing techniques pertaining to image-based velocimetry. The technique is therefore called Acoustic Mapping Velocimetry (AMV). The implementation of this technique produces a whole-field velocity map associated with the multi-directional bedform movement. Based on the calculated two-dimensional bedform migration velocity field, the bedload transport estimation is done using the Exner equation. A proof-of-concept experiment was performed to validate the AMV based bedload estimation in a laboratory flume at IIHR-Hydroscience & Engineering (IIHR). The bedform migration was analysed at three different flow discharges. Repeated bed geometry mapping, using a multiple transducer array (MTA), provided acoustic maps, which were post-processed with a particle image velocimetry (PIV) method. Bedload transport rates were calculated along longitudinal sections using the streamwise components of the bedform velocity vectors and the measured bedform heights. The bulk transport rates were compared with the results from concurrent direct physical samplings and acceptable agreement was found. As a first field implementation of the AMV an attempt was made to estimate bedload transport for a section of the Ohio river in the United States, where bed geometry maps, resulted by repeated multibeam echo sounder (MBES) surveys, served as input data. Cross-sectional distributions of bedload transport rates from the AMV based method were compared with the ones obtained from another non-intrusive technique (due to the lack of direct samplings), ISSDOTv2, developed by the US Army

  19. ImagingSIMS

    Energy Technology Data Exchange (ETDEWEB)

    2017-11-06

    ImagingSIMS is an open source application for loading, processing, manipulating and visualizing secondary ion mass spectrometry (SIMS) data. At PNNL, a separate branch has been further developed to incorporate application specific features for dynamic SIMS data sets. These include loading CAMECA IMS-1280, NanoSIMS and modified IMS-4f raw data, creating isotopic ratio images and stitching together images from adjacent interrogation regions. In addition to other modifications of the parent open source version, this version is equipped with a point-by-point image registration tool to assist with streamlining the image fusion process.

  20. A 1.9 μW 4.4 fJ/conversion-step, 10 bit, 1 MS/s charge redistribution ADC

    NARCIS (Netherlands)

    van Elzakker, Michel; van Tuijl, Adrianus Johannes Maria; Geraedts, P.F.J.; Schinkel, Daniel; Klumperink, Eric A.M.; Nauta, Bram

    2008-01-01

    A 10b SAR ADC uses a charge redistribution DAC, a two-stage comparator, and a delay-line-based controller. The ADC does not use any static bias current and power consumption is proportional to sample rate. At 1MS/s, the ADC uses 1.9μW. With 8.75 ENOB, the resulting FOM is 4.4fJ/conversion-step.

  1. Comparison of calculated curves of profiling for induction probes 4I1, 4F0. 75, and 6F1 against bed composites without considering the skin effect

    Energy Technology Data Exchange (ETDEWEB)

    Afenino, N.M.; Plyusnin, M.I.; Putsyato, L.A.; Vaksman, K.G.

    1981-01-01

    Described are curves of profiling of probes 4I1, 4F0.75, and 6F1, calculated for models of bed composites which correspond to the most typical cross sections of oil exploration boreholes of Western Siberia, and the possibilities of these probes are discussed in connection with the classification of the cross section and determination of the specific electric resistance of individual beds.

  2. Detergent-induced stabilization and improved 3D map of the human heteromeric amino acid transporter 4F2hc-LAT2.

    Directory of Open Access Journals (Sweden)

    Marcel Meury

    Full Text Available Human heteromeric amino acid transporters (HATs are membrane protein complexes that facilitate the transport of specific amino acids across cell membranes. Loss of function or overexpression of these transporters is implicated in several human diseases such as renal aminoacidurias and cancer. HATs are composed of two subunits, a heavy and a light subunit, that are covalently connected by a disulphide bridge. Light subunits catalyse amino acid transport and consist of twelve transmembrane α-helix domains. Heavy subunits are type II membrane N-glycoproteins with a large extracellular domain and are involved in the trafficking of the complex to the plasma membrane. Structural information on HATs is scarce because of the difficulty in heterologous overexpression. Recently, we had a major breakthrough with the overexpression of a recombinant HAT, 4F2hc-LAT2, in the methylotrophic yeast Pichia pastoris. Microgram amounts of purified protein made possible the reconstruction of the first 3D map of a human HAT by negative-stain transmission electron microscopy. Here we report the important stabilization of purified human 4F2hc-LAT2 using a combination of two detergents, i.e., n-dodecyl-β-D-maltopyranoside and lauryl maltose neopentyl glycol, and cholesteryl hemisuccinate. The superior quality and stability of purified 4F2hc-LAT2 allowed the measurement of substrate binding by scintillation proximity assay. In addition, an improved 3D map of this HAT could be obtained. The detergent-induced stabilization of the purified human 4F2hc-LAT2 complex presented here paves the way towards its crystallization and structure determination at high-resolution, and thus the elucidation of the working mechanism of this important protein complex at the molecular level.

  3. Lanthanide 4f-level location in lanthanide doped and cerium-lanthanide codoped NaLaF4 by photo- and thermoluminescence

    NARCIS (Netherlands)

    Krumpel, A.H.; Van der Kolk, E.; Zeelenberg, D.; Bos, A.J.J.; Krämer, K.W.; Dorenbos, P.

    2008-01-01

    Photo- and thermoluminescence (TL) spectra of NaLaF4:Ln3+ (Ln = Ce,Pr,Nd,Sm,Eu,Gd,Tb,Dy,Ho,Er,Tm) and NaLaF4:Ce3+, Ln3+ (Ln = Nd,Sm,Ho,Er,Tm) are presented and used together with the empirical Dorenbos model in order to establish the 4f energy level positions of all tri- and divalent lanthanide ions

  4. Temporal variation of the electron density in afterglow of high-density CF_4, C_4F_8, and CF_4--H2 plasmas

    Science.gov (United States)

    Sasaki, K.; Kadota, K.

    1998-10-01

    The kinetics of electrons in electronegative plasmas is greatly affected by dissociative attachment to neutral molecules, which is a major process for the formation of negative ions. In fluorocarbon plasmas, negative fluorine ions (F^-) are produced by electron attachment to various reaction products as well as the parent gas. In the present work, we have measured the temporal variation of the electron density in the afterglow of high-density CF_4, C_4F_8, and CF_4--H2 plasmas. A conventional microwave interferometer at 35 GHz was adopted for the measurement. The electron loss frequency was evaluated from the temporal variation of the electron density which was calculated from the interferometry signal digitized with a high sampling rate of 100 MHz. In CF4 plasmas, the variation of the electron loss frequency roughly corresponded to that of the neutral radical densities. In C_4F8 plasmas, the electron loss frequency was higher for the discharge condition with lower dissociation degree. These results indicates that reaction products play important roles for the production of F^- in CF4 plasmas, while in C_4F8 plasmas, the production of F^- is governed by the parent gas. No correlations were found between the electron loss frequency and the F atom density in CF_4--H2 plasmas, which suggests that the production of F^- from F2 is nearly negligible.

  5. Picosecond spin dynamics of Gd(0001) studied by linear dichroism of 4f shell. A time-resolved experiment combined laser and synchrotron radiation

    Energy Technology Data Exchange (ETDEWEB)

    Garcia, Helena Prima; Schmidt, Roland; Weinelt, Martin [Max-Born-Institute, Berlin (Germany); Melnikov, Alexev; Lisowski, Martin; Bovensiepen, Uwe [Freie Universitaet, Berlin (Germany)

    2007-07-01

    We have studied ultrafast magnetization dynamics in Gd(0001) films alignment by time-resolved X-ray photoemission spectroscopy. Absorption of a 50 fs laser-pump-pulse at 800 nm leads to optical excitation of the Gd valence electrons. We probe the relaxation dynamics by linear dichroism in photoemission from the Gd 4f electrons using a 60 eV, 50 ps probe-pulse at the synchrotron user facility BESSY, Germany. Linear dichroism in photoemission is proportional to the magnetic moment of the 4f{sup 7} electrons. The breakdown of the magnetic ordering upon fs laser excitation has been reported basedmagneto-optical studies to occur within 100 fs. The recovery of the equilibrium magnetization is driven by cooling of the lattice and spinlattice interaction. It proceeds on a 100 ps time scale. Here we show the breakdown of the magnetic moment after laser excitation within the probe pulse duration and the subsequent recovery to the equilibrium value. As linear dichroism is a measure of the alignment of the Gd 4f moments, its breakdown is a further proof of laser-induced demagnetization.

  6. Inhibition of VEGF-dependent angiogenesis by the anti-CD82 monoclonal antibody 4F9 through regulation of lipid raft microdomains

    Energy Technology Data Exchange (ETDEWEB)

    Nomura, Sayaka; Iwata, Satoshi; Hatano, Ryo [Division of Clinical Immunology, Advanced Clinical Research Center, The Institute of Medical Science, The University of Tokyo, 4-6-1 Shirokanedai, Minato-ku, Tokyo, 108-8639 (Japan); Komiya, Eriko [Department of Therapy Development and Innovation for Immune Disorders and Cancers, Graduate School of Medicine, Juntendo University, 2-1-1, Hongo, Bunkyo-ku, Tokyo, 113-8421 (Japan); Dang, Nam H. [Division of Hematology/Oncology, University of Florida, 1600 SW Archer Road- Box 100278, Room MSB M410A, Gainesville, FL, 32610 (United States); Iwao, Noriaki [Department of Hematology, School of Medicine, Juntendo University, 2-1-1, Hongo, Bunkyo-ku, Tokyo, 113-8421 (Japan); Ohnuma, Kei, E-mail: kohnuma@juntendo.ac.jp [Department of Rheumatology and Allergy, IMSUT Hospital, The Institute of Medical Science, The University of Tokyo, 4-6-1 Shirokanedai, Minato-ku, Tokyo, 108-8639 (Japan); Morimoto, Chikao [Division of Clinical Immunology, Advanced Clinical Research Center, The Institute of Medical Science, The University of Tokyo, 4-6-1 Shirokanedai, Minato-ku, Tokyo, 108-8639 (Japan); Department of Rheumatology and Allergy, IMSUT Hospital, The Institute of Medical Science, The University of Tokyo, 4-6-1 Shirokanedai, Minato-ku, Tokyo, 108-8639 (Japan)

    2016-05-20

    CD82 (also known as KAI1) belongs to the tetraspanin superfamily of type III transmembrane proteins, and is involved in regulating cell adhesion, migration and proliferation. In contrast to these well-established roles of CD82 in tumor biology, its function in endothelial cell (EC) activity and tumor angiogenesis is yet to be determined. In this study, we show that suppression of CD82 negatively regulates vascular endothelial growth factor (VEGF)-induced angiogenesis. Moreover, we demonstrate that the anti-CD82 mAb 4F9 effectively inhibits phosphorylation of VEGF receptor 2 (VEGFR2), which is the principal mediator of the VEGF-induced angiogenic signaling process in tumor angiogenesis, by regulating the organization of the lipid raft microdomain signaling platform in human EC. Our present work therefore suggests that CD82 on EC is a potential target for anti-angiogenic therapy in VEGFR2-dependent tumor angiogenesis. -- Highlights: •Knockdown of CD82 decreases EC migration, proliferation and angiogenesis. •Anti-CD82 mAb 4F9 inhibits EC migration, proliferation and angiogenesis. •4F9 inhibits VEGFR2 phosphorylation via control of CD82 distribution in lipid rafts.

  7. Acoustic approximations of elastic media with fast variations

    Science.gov (United States)

    Cance, P.; Capdeville, Y.

    2013-12-01

    Imaging the Earth using seismic waveforms is an intensive computational problem. Reducing numerical cost of the forward problem is therefore an important objective. At the exploration seismic imaging scale, a common practical method relies on using only P-waves information. In such case, an acoustic approximation of the elastic forward problem is often used, which reduces drastically the numerical cost, not only because the problem is smaller but mainly because the expense of correctly sampling slow S-waves is not present anymore. If this approximation is valid for slowly varying isotropic media, this is not the case in general. The present work focuses on acoustic approaches of heterogeneous elastic media with heterogeneity sizes much smaller than the propagating wavelength as well as acoustic anisotropy. A useful tool to study those rapidly varying heterogeneous media is the non periodic homogenization for waves (Capdeville et al. 2009;2010). This homogenization procedure has been adapted and applied to acoustic media. While upscaling the elastic wave equation induces elastic apparent anisotropy, we show that in the acoustic case, it is the density that becomes anisotropic. Unfortunately the induced anisotropy is not of the same nature between elastic cases and acoustic cases (in the acoustic case it proves to remain only an elliptic anisotropy) which prevent to use acoustic anisotropy to mimic elastic anisotropy. If building the acoustic media from the elastic one is obvious for slowly varying isotropic media, it is not the case anymore for rapidly varying media nor for anisotropic media. To check if these difficulties can be overcome and if at least P-waves first arrivals can be correctly reproduced we propose here two methods for building the acoustic media from the elastic one. We will refer to the first method as the 'physical method' as it tends to keep track of the physical parameters of the original medium, and to the second method as the 'mathematical

  8. Evoked acoustic emission

    DEFF Research Database (Denmark)

    Elberling, C; Parbo, J; Johnsen, N J

    1985-01-01

    Stimulated acoustic emissions were recorded in response to tonal stimuli at 60 dB p.e. SPL in a small group of normal-hearing adults. Power spectral analysis reveals that the evoked activity from each ear contains energy in preferential frequency bands and the change of stimulus frequency has only...

  9. Underwater Acoustic Networking Techniques

    CERN Document Server

    Otnes, Roald; Casari, Paolo; Goetz, Michael; Husøy, Thor; Nissen, Ivor; Rimstad, Knut; van Walree, Paul; Zorzi, Michele

    2012-01-01

    This literature study presents an overview of underwater acoustic networking. It provides a background and describes the state of the art of all networking facets that are relevant for underwater applications. This report serves both as an introduction to the subject and as a summary of existing protocols, providing support and inspiration for the development of network architectures.

  10. Intelligent Engine Systems: Acoustics

    Science.gov (United States)

    Wojno, John; Martens, Steve; Simpson, Benjamin

    2008-01-01

    An extensive study of new fan exhaust nozzle technologies was performed. Three new uniform chevron nozzles were designed, based on extensive CFD analysis. Two new azimuthally varying variants were defined. All five were tested, along with two existing nozzles, on a representative model-scale, medium BPR exhaust nozzle. Substantial acoustic benefits were obtained from the uniform chevron nozzle designs, the best benefit being provided by an existing design. However, one of the azimuthally varying nozzle designs exhibited even better performance than any of the uniform chevron nozzles. In addition to the fan chevron nozzles, a new technology was demonstrated, using devices that enhance mixing when applied to an exhaust nozzle. The acoustic benefits from these devices applied to medium BPR nozzles were similar, and in some cases superior to, those obtained from conventional uniform chevron nozzles. However, none of the low noise technologies provided equivalent acoustic benefits on a model-scale high BPR exhaust nozzle, similar to current large commercial applications. New technologies must be identified to improve the acoustics of state-of-the-art high BPR jet engines.

  11. Deep Water Ocean Acoustics

    Science.gov (United States)

    2015-07-17

    Society of America 125 (4), 1394-1402 (2008). 2 J.W. Goodman , Introduction to Fourier Optics . (Roberts & Company, 2005). 3 George L Pickard and William...3 1. Introduction ...Report No. QSR-14C0172-Ocean Acoustics-063015 Technical Progress Report 1. Introduction The goal of this research is to increase our understanding

  12. Acoustic Neuroma Educational Video

    Medline Plus

    Full Text Available ... Surgery What is acoustic neuroma Diagnosing Symptoms Side effects ... Groups Is a support group for me? Find a Group Upcoming Events Video Library Photo Gallery One-on-One Support ANetwork Peer Support Program Community Connections Overview Find a Meeting ...

  13. Select Internet Resources on Acoustics

    Directory of Open Access Journals (Sweden)

    Angela R. Davis

    2016-12-01

    Full Text Available Merriam-Webster (2016 defines acoustics as, “a science that deals with the production, control, transmission, reception, and effects of sounds.” According to Rossing (2014, the study of acoustics began in ancient Greece with Pythagoras’ study of vibrating strings on musical instruments. Since those early beginnings, famous scientists including Rayleigh, Alexander Graham Bell, and Thomas Edison, have helped expand the field of acoustics to include architectural, physical, engineering, structural, underwater, physiological and psychological, musical acoustics, and speech. Acoustics is a highly interdisciplinary field and researchers may need resources from physics, medicine, and engineering to understand all aspects of their research.

  14. Development of Optical Measurement Techniques for Thermo-Acoustic Diagnostics: Fibre-Optic Microphone, Rayleigh-Scattering, and Acoustic PIV

    Directory of Open Access Journals (Sweden)

    H. Konle

    2009-06-01

    Full Text Available Thermo-acoustic investigations require reliable measurement techniques in hot environments for pressure, density fluctuations with a high dynamic range and acoustic particle velocity. This paper presents recent developments of optical measurement techniques in combustion diagnostics. A fibre-optic microphone based on the interferometric detection of membrane deflections was designed to measure acoustic pressure oscillations. Due to the heat resistant design, the sensor has an upper temperature limitation of approximately 970 K. Rayleigh-Scattering measurements, using the density dependent intensity of scattered light were performed in an unconfined flame with approximately 1600 K to study amplitude and phase distribution of the flame pulsation. Acoustic particle velocity can be determined applying acoustic PIV (particle image velocimetry technique. This paper shows a way to measure simultaneously the acoustic particle velocity and the locally resolved mean flow velocity of a turbulent flow. Together these non-invasive techniques are applicable to study thermo-acoustic processes and sound generation in combustion chambers or turbines.

  15. Classroom Materials from the Acoustical Society of America

    Science.gov (United States)

    Adams, W. K.; Clark, A.; Schneider, K.

    2013-09-01

    As part of the new education initiatives of the Acoustical Society of America (ASA), an activity kit for teachers that includes a variety of lessons addressing acoustics for a range of students (K-12) has been created. The "Sound and Music Activity Kit" is free to K-12 teachers. It includes materials sufficient to teach a class of 30 students plus a USB thumb drive containing 47 research-based, interactive, student-tested lessons, laboratory exercises, several assessments, and video clips of a class using the materials. ASA has also partnered with both the Optical Society of America (OSA) and the American Association of Physics Teachers. AAPT Physics Teaching Resource Agents (PTRA) have reviewed the lessons along with members of the ASA Teacher Activity Kit Committee. Topics include basic learning goals for teaching the physics of sound with examples and applications relating to medical imaging, animal bioacoustics, physical and psychological acoustics, speech, audiology, and architectural acoustics.

  16. Hemorrhage and abnormal veins in acoustic neurinoma. MR findings

    Energy Technology Data Exchange (ETDEWEB)

    Ishii, Kiyoshi; Takahashi, Shoki; Matsumoto, Ko; Ishibashi, Tadashi; Sakamoto, Kiyohiko; Hashimoto, Sho; Katakura, Ryuichi; Ogawa, Akira [Tohoku Univ., Sendai (Japan). School of Medicine; Yuasa, Ryo

    1996-03-01

    We reviewed the MR imaging findings of 57 acoustic neurinomas which were verified at surgery or diagnosed on the basis of neuroradiological and neurootological data. Two uncommon MR findings of acoustic neurinoma were found. First, hypointense areas were observed on T{sub 2}-weighted images in five of the 12 tumors larger than 25 mm in diameter. These hypointense areas represented hemosiderin deposition secondary to occult intratumoral hemorrhage. Second, curvilinear or round signal voids were noted at the periphery of 11 large or medium-sized tumors, and these corresponded to `abnormal veins` seen on angiographic studies. (author)

  17. Acoustic precursor wave propagation in viscoelastic media.

    Science.gov (United States)

    Zhu, Guangran Kevin; Mojahedi, Mohammad; Sarris, Costas D

    2014-03-01

    Precursor field theory has been developed to describe the dynamics of electromagnetic field evolution in causally attenuative and dispersive media. In Debye dielectrics, the so-called Brillouin precursor exhibits an algebraic attenuation rate that makes it an ideal pulse waveform for communication, sensing, and imaging applications. Inspired by these studies in the electromagnetic domain, the present paper explores the propagation of acoustic precursors in dispersive media, with emphasis on biological media. To this end, a recently proposed causal dispersive model is employed, based on its interpretation as the acoustic counterpart of the Cole¿Cole model for dielectrics. The model stems from the fractional stress¿strain relation, which is consistent with the empirically known frequency power-law attenuation in viscoelastic media. It is shown that viscoelastic media described by this model, including human blood, support the formation and propagation of Brillouin precursors. The amplitude of these precursors exhibits a sub-exponential attenuation rate as a function of distance, actually being proportional to z(-p), where z is the distance traveled within the medium and 0.5

    acoustic-pulse-based communication and imaging systems.

  18. Order–disorder phase transition in the antiperovskite-type structure of synthetic kogarkoite, Na{sub 3}SO{sub 4}F

    Energy Technology Data Exchange (ETDEWEB)

    Avdontceva, Margarita S.; Zolotarev, Andrey A. [Department of Crystallography, Institute of Earth Sciences, St. Petersburg State University, University Emb. 7/9, 199034 St. Petersburg (Russian Federation); Krivovichev, Sergey V., E-mail: s.krivovichev@spbu.ru [Department of Crystallography, Institute of Earth Sciences, St. Petersburg State University, University Emb. 7/9, 199034 St. Petersburg (Russian Federation); Institute of Silicate Chemistry, Russian Academy of Sciences, Makarova Emb. 6, 199034 St. Petersburg (Russian Federation)

    2015-11-15

    High-temperature phase transition of synthetic kogarkoite, Na{sub 3}SO{sub 4}F, has been studied by high-temperature X-ray powder and single-crystal diffraction. The temperature of the phase transition can be estimated as 112.5±12.5 °C. The low-temperature phase, α-Na{sub 3}SO{sub 4}F, at 293 K, is monoclinic, P2{sub 1}/m, a=18.065(3), b=6.958(1), c=11.446(1) Å, β=107.711(1)°, Z=12. The structure contains thirteen symmetrically independent Na sites with coordination numbers varying from 6 to 8, and six independent S sites. The high-temperature β-phase at 423 K is rhombohedral, R-3m, a=6.94(1), c=24.58(4) Å, Z=9. The crystal structure of both polymorphs of Na{sub 3}SO{sub 4}F can be described as a 9R antiperovskite polytype based upon triplets of face-sharing [FNa{sub 6}] octahedra linked into a three-dimensional framework by sharing corners. In the α-modification, the SO{sub 4} tetrahedra are completely ordered and located in the framework cavities. In the β-modification, there are only two symmetrically independent Na atoms in the structure. The main difference between the structures of the α- and β-phases is the degree of ordering of the SO{sub 4} tetrahedra: in the α-modification, they are completely ordered, whereas, in the β-modification, the complete disorder is observed, which is manifested in a number of low-occupied O sites around fully occupied S sites. The phase transition is therefore has an order–disorder character and is associated with the decrease of structural complexity measured as an information content per unit cell [577.528 bits for the low- (α) and 154.830 bits for the high- (β) temperature modifications]. - Graphical abstract: High-temperature phase transition of synthetic kogarkoite, Na{sub 3}SO{sub 4}F, revealed the existence of the monoclinic-to-rhombohedral phase transition at 112.5±12.5 °C. The phase transition has an order–disorder character and is associated with the decrease of structural complexity. - Highlights

  19. Combining electronic structure and many-body theory with large databases: A method for predicting the nature of 4 f states in Ce compounds

    Science.gov (United States)

    Herper, H. C.; Ahmed, T.; Wills, J. M.; Di Marco, I.; Björkman, T.; Iuşan, D.; Balatsky, A. V.; Eriksson, O.

    2017-08-01

    Recent progress in materials informatics has opened up the possibility of a new approach to accessing properties of materials in which one assays the aggregate properties of a large set of materials within the same class in addition to a detailed investigation of each compound in that class. Here we present a large scale investigation of electronic properties and correlated magnetism in Ce-based compounds accompanied by a systematic study of the electronic structure and 4 f -hybridization function of a large body of Ce compounds. We systematically study the electronic structure and 4 f -hybridization function of a large body of Ce compounds with the goal of elucidating the nature of the 4 f states and their interrelation with the measured Kondo energy in these compounds. The hybridization function has been analyzed for more than 350 data sets (being part of the IMS database) of cubic Ce compounds using electronic structure theory that relies on a full-potential approach. We demonstrate that the strength of the hybridization function, evaluated in this way, allows us to draw precise conclusions about the degree of localization of the 4 f states in these compounds. The theoretical results are entirely consistent with all experimental information, relevant to the degree of 4 f localization for all investigated materials. Furthermore, a more detailed analysis of the electronic structure and the hybridization function allows us to make precise statements about Kondo correlations in these systems. The calculated hybridization functions, together with the corresponding density of states, reproduce the expected exponential behavior of the observed Kondo temperatures and prove a consistent trend in real materials. This trend allows us to predict which systems may be correctly identified as Kondo systems. A strong anticorrelation between the size of the hybridization function and the volume of the systems has been observed. The information entropy for this set of systems is

  20. Atmospheric histories and growth trends of C4F10, C5F12, C6F14, C7F16 and C8F18

    Directory of Open Access Journals (Sweden)

    R. F. Weiss

    2012-05-01

    Full Text Available Atmospheric observations and trends are presented for the high molecular weight perfluorocarbons (PFCs: decafluorobutane (C4F10, dodecafluoropentane (C5F12, tetradecafluorohexane (C6F14, hexadecafluoroheptane (C7F16 and octadecafluorooctane (C8F18. Their atmospheric histories are based on measurements of 36 Northern Hemisphere and 46 Southern Hemisphere archived air samples collected between 1973 to 2011 using the Advanced Global Atmospheric Gases Experiment (AGAGE "Medusa" preconcentration gas chromatography-mass spectrometry systems. A new calibration scale was prepared for each PFC, with estimated accuracies of 6.8% for C4F10, 7.8% for C5F12, 4.0% for C6F14, 6.6% for C7F16 and 7.9% for C8F18. Based on our observations the 2011 globally averaged dry air mole fractions of these heavy PFCs are: 0.17 parts-per-trillion (ppt, i.e., parts per 1012 for C4F10, 0.12 ppt for C5F12, 0.27 ppt for C6F14, 0.12 ppt for C7F16 and 0.09 ppt for C8F18. These atmospheric mole fractions combine to contribute to a global average radiative forcing of 0.35 mW m−2, which is 6% of the total anthropogenic PFC radiative forcing (Montzka and Reimann, 2011; Oram et al., 2012. The growth rates of the heavy perfluorocarbons were largest in the late 1990s peaking at 6.2 parts per quadrillion (ppq, i.e., parts per 1015 per year (yr for C4F10, at 5.0 ppq yr−1 for C5F12 and 16.6 ppq yr−1 for C6F14 and in the early 1990s for C7F16 at 4.7 ppq yr−1 and in the mid 1990s for C8F18 at 4.8 ppq yr−1. The 2011 globally averaged mean atmospheric growth rates of these PFCs are subsequently lower at 2.2 ppq yr−1 for C4F10, 1.4 ppq yr−1 for C5F12, 5.0 ppq yr−1 for C6F14, 3.4 ppq yr−1 for C7F16 and 0.9 ppq yr−1 for C8F18. The more recent slowdown in the growth rates suggests that emissions are declining as compared to the 1980s and 1990s.