Topics

PubMed Journals Articles About "Effects Phase Modulated Excitation Focused Acoustic Field" RSS

23:45 EST 20th January 2020 | BioPortfolio

Effects Phase Modulated Excitation Focused Acoustic Field PubMed articles on BioPortfolio. Our PubMed references draw on over 21 million records from the medical literature. Here you can see the latest Effects Phase Modulated Excitation Focused Acoustic Field articles that have been published worldwide.

More Information about "Effects Phase Modulated Excitation Focused Acoustic Field" on BioPortfolio

We have published hundreds of Effects Phase Modulated Excitation Focused Acoustic Field news stories on BioPortfolio along with dozens of Effects Phase Modulated Excitation Focused Acoustic Field Clinical Trials and PubMed Articles about Effects Phase Modulated Excitation Focused Acoustic Field for you to read. In addition to the medical data, news and clinical trials, BioPortfolio also has a large collection of Effects Phase Modulated Excitation Focused Acoustic Field Companies in our database. You can also find out about relevant Effects Phase Modulated Excitation Focused Acoustic Field Drugs and Medications on this site too.

Showing "effects phase modulated excitation focused acoustic field" PubMed Articles 1–25 of 39,000+

The effects of phase modulated excitation on the focused acoustic field.

Various modulation approaches, such as amplitude and frequency modulation, have been applied widely to modify the acoustic field and improve the performance of ultrasound imaging and therapy. However, phase modulation has not been investigated extensively in the ultrasound applications, especially at long pulse duration. In this study, the effects of phase modulation on the acoustic field were investigated. The radiated acoustic pressure waveforms produced using different phase modulation strategies (i.e., ...


Dynamical diffraction effects on the geometric phase of inhomogeneous strain fields.

In specimens with an inhomogeneous displacement field in electron beam direction dynamical diffraction effects lead to complex non-linear properties of the diffracted electron wave. Consequently, the diffracted beam's phase contains information about the inhomogeneous displacement field. These phases are experimentally and theoretically investigated under different excitation errors and specimen thicknesses as well as for different depths of the displacement field. An inclined InGaAs layer with a larger lat...

Theoretically Estimating the Acoustic Intensity of High-Intensity Focused Ultrasound (HIFU) Using Infrared Thermography.

High-intensity focused ultrasound (HIFU) has been used successfully in clinics for the treatment of a variety of cancerous and benign tumors. Characterization of the focused acoustic field is of importance in the planning of ablation procedure and further development of HIFU technology. Quantitative estimation of acoustic intensity is feasible using the infrared thermography on an absorber. However, the current approach is limited to low power output. In this study, a theoretical model was established to de...


Raman Spectra of La3Ga5SiO14 Crystal Modulated by Bulk Acoustic Wave.

Influence of bulk acoustic wave excitation in langasite crystal on Raman spectra was studied. It was found that acoustic wave propagating in the crystal volume changes the intensity and position of the Raman scattering lines. Under bulk acoustic wave propagation conditions Raman peak intensity changes less than on 5% and peak position shifts on 0.5 cm-1. To detect such small changes principal component analysis of Raman spectra was used.

Generating Bessel beams with broad depth-of-field by using phase-only acoustic holograms.

We report zero-th and high-order acoustic Bessel beams with broad depth-of-field generated using acoustic holograms. While the transverse field distribution of Bessel beams generated using traditional passive methods is correctly described by a Bessel function, these methods present a common drawback: the axial distribution of the field is not constant, as required for ideal Bessel beams. In this work, we experimentally, numerically and theoretically report acoustic truncated Bessel beams of flat-intensity ...

Novel Acoustic Coupling Bath using Magnetite Nanoparticles for MR-Guided Transcranial Focused Ultrasound Surgery.

Acoustic coupling baths, nominally composed of degassed water, play important roles during transcranial focused ultrasound surgery. However, this large water bolus also degrades the quality of intraoperative magnetic resonance (MR) guidance imaging. In this study, we test the feasibility of using dilute, aqueous magnetite nanoparticle suspensions to suppress these image degradations while preserving acoustic compatibility. We examine the effects of these suspensions on metrics of image quality and acoustic ...

Heating of Polymer Films Induced by High-Intensity Focused Ultrasound: Study of Acoustic and Thermal Effects.

This paper presents the study of the thermal and acoustic effects occurring in polymer samples of different thicknesses receiving high-intensity focused ultrasound (HIFU). Whereas the heating mechanisms in polymer plates immersed in water are well known, the physical mechanisms enabling the heating of polymer films using a solid waveguide transducer remain not fully understood. A coupled acousto-thermal finite element simulation is conducted to model the sound field and the heat generation inside polymer sa...

Evaluation of magnetic resonance imaging acoustic noise reduction technology by magnetic gradient waveform control.

ComforTone is a noise reduction technology used in magnetic resonance imaging (MRI) systems; it suppresses acoustic noise by modifying pulse sequences, which appropriately changes the magnetic field gradient waveforms. Although ComforTone can be used to solve the acoustic noise problems that affect patients who are exposed to acoustic noise from MRI, to the best of our knowledge, the associated technical details have not been published and its effects on acoustic noise reduction remain unclear.

Experimental study on eliminating fire smokes using acoustic agglomeration technology.

Acoustic agglomeration is a process in which an intense sound field is applied to promote relative motion and rapid agglomeration among aerosol particles. This technology is able to improve significantly and rapidly the visibility of the smoke in a fire situation, and therefore assists the quick evacuation of evacuees. In this paper, the elimination effect of polystyrene smoke using acoustic agglomeration technology is experimentally investigated. The results show that the smoke transmittance will be increa...

Computational Phase-Modulated Eyeglasses.

We present computational phase-modulated eyeglasses, a see-through optical system that modulates the view of the user using phase-only spatial light modulators (PSLM). A PSLM is a programmable reflective device that can selectively retardate, or delay, the incoming light rays. As a result, a PSLM works as a computational dynamic lens device. We demonstrate our computational phase-modulated eyeglasses with either a single PSLM or dual PSLMs and show that the concept can realize various optical operations inc...

Linear phase design of piezoelectric transducers for acousto-optic dispersion delay lines using differential evolution for matching circuit optimization.

A numerical method for providing linear phase response of bulk acoustic wave (BAW) piezoelectric transducers of acousto-optic devices is developed. Our approach is based on analytic approximation of the phase response of the piezoelectric transducer with the matching electrical circuit and optimization with a differential evolution genetic algorithm. Simulations and experiments were performed for two typical BAW excitation schemes: direct and reflective. Variance of the group delay in the specified frequenc...

Acoustic vortex beams in synthetic magnetic fields.

We analyze propagation of acoustic vortex beams in longitudinal synthetic magnetic fields. We show how to generate two field configurations using a fluid contained in circulating cylinders: a uniform synthetic magnetic field hosting Laguerre-Gauss modes, and an Aharonov-Bohm flux tube hosting Bessel beams. For non-paraxial beams we find qualitative differences from the well-studied case of electron vortex beams in magnetic fields, arising due to the vectorial nature of the acoustic wave's velocity field. In...

Assembling and rotating erythrocyte aggregates by acoustofluidic pressure enabling full phase-contrast tomography.

The combined use of ultrasound radiation and microfluidics is a promising tool for aiding the development of lab-on-a-chip devices. In this study, we show that the rotation of linear aggregates of micro-particles can be achieved under the action of acoustic field pressure. This novel manipulation is investigated by tracking polystyrene beads of different sizes through the 3D imaging features of digital holography (DH). From our analysis it is understood that the positioning of the micro-particles and their ...

Topological phases and pumps in the Su-Schrieffer-Heeger model periodically modulated in time.

By the Floquet theory, we transform the Su-Schrieffer-Heeger model with the periodically modulated nearest-neighbor and next-nearest-neighbor interactions into an effective 2D model, which holds the total Chern number of ±1 modulated by the parameter θ. Under a staggered electric potential, the topological phase diagrams of the effective 2D model are reshaped and similar to the well-known Haldane model. While under a staggered Zeeman field, the topological phase diagram has the same shape as the former ca...

Analysis of velocity calculation methods of laser-induced surface acoustic wave.

The key to measuring residual stress by surface acoustic wave method is the accurate measurement of velocity. In this paper, the velocity of laser-induced broadband surface acoustic wave is studied, and three velocity calculation methods of surface acoustic wave, time domain method, phase method and wavelet method are compared. The calculation error of the time domain method under the condition of dispersion is analyzed. A recursive method for calculating phase difference is proposed to improve the efficien...

Three-dimensional acoustic impedance mapping of cultured biological cells.

The acoustic microscope is a powerful tool for the observation of biological matters. Non-invasive in-situ observation can be performed without any staining process. Acoustic microscopy is contrasted by elastic parameters like sound speed and acoustic impedance. We have proposed an acoustic microscope that can acquire three-dimensional acoustic impedance profile. The technique was applied to cell-size observation. Glial cells were cultured on a 70 μm-thick polypropylene film substrate. A highly focused u...

Excitation and detection of evanescent acoustic waves in piezoelectric plates: Theoretical and 2D FEM modeling.

This paper presents the results of the theoretical and 2D FEM modeling excitation and detection of evanescent acoustic waves in piezoelectric plates. By application of 2D ordinary differential equations derived by Auld, we obtained the dispersion curves of A and SH waves in YX LiNbO and YX KNbO plates in proximity to a zero group velocity point. The branches corresponding to evanescent acoustic waves are distinguished. A frequency range where real part of evanescent wave velocity is more than imaginary one ...

High Intensity Focused Electromagnetic Field (HIFEM) Devices in Dermatology“

Electromagnetic field devices, specifically high intensity focused electro-magnetic field (HIFEM), comprise the latest class of technologies being developed for dermatologic applications. The FDA clearance of these technologies includes such intended uses as “the stimulation of neuromuscular tissue for bulk muscle excitation in the legs or arms” and improvement of abdominal tone, strengthening of the abdominal muscles, development of firmer abdomen; strengthening, toning and firming of buttocks, thighs ...

Acoustic Shadowing Facilitates Ultrasound-guided Radial Artery Cannulation in Young Children.

Arterial cannulation in young children can be challenging. Ultrasound guidance using focused acoustic shadowing may be suitable for guiding radial artery puncture in young children. The present research tested the hypothesis that ultrasound guidance using focused acoustic shadowing helps increase the success rate of radial artery cannulation in this population.

The effect of transcranial focused ultrasound target location on the acoustic feedback control performance during blood-brain barrier opening with nanobubbles.

Real-time acoustic feedback control based on harmonic emissions of stimulated microbubbles may be important for facilitating the clinical adoption of focused ultrasound (FUS)-induced blood-brain barrier (BBB) opening, both to ensure safe acoustic exposures, and to achieve repeatable and consistent opening. Previously our group demonstrated that successful BBB opening was achievable with both commercially available microbubbles and custom-made nanobubbles under acoustic feedback control. In a recent study, w...

Noninvasive Induction of Muscle Fiber Hypertrophy and Hyperplasia: Effects of High-Intensity Focused Electromagnetic Field Evaluated in an In-Vivo Porcine Model: A Pilot Study.

High-intensity focused electromagnetic (HIFEM) field technology has been reported to increase muscle thickness and hypertrophy. However, this process has not yet been confirmed on a histologic level.

Ligand shell size effects on one- and two-photon excitation fluorescence of zwitterion functionalized gold nanoclusters.

Gold nanoclusters (Au NCs) are an emerging class of luminescent nanomaterials but still suffer from moderate photoluminescence quantum yields. Recent efforts have focused on tailoring their emission properties. Introducing zwitterionic ligands to cap the metallic kernel is an efficient approach to enhance their one-photon excitation fluorescence intensity. In this work, we extend this concept to the nonlinear optical regime, i.e., two-photon excitation fluorescence. For a proper comparison between theory an...

The origins of acoustic communication in vertebrates.

Acoustic communication is crucial to humans and many other tetrapods, including birds, frogs, crocodilians, and mammals. However, large-scale patterns in its evolution are largely unstudied. Here, we address several fundamental questions about the origins of acoustic communication in terrestrial vertebrates (tetrapods), using phylogenetic methods. We show that origins of acoustic communication are significantly associated with nocturnal activity. We find that acoustic communication does not increase diversi...

Laser-assisted MAL-PDT associated with acoustic pressure wave ultrasound with short incubation time for field cancerization treatment: a left-right comparison.

Laser-assisted MAL-PDT has been reported to increase the effectiveness of conventional PDT. Nonetheless, clinical effects of this association when reducing MAL incubation time is poorly discussed. Furthermore, the association of acoustic pressure wave ultrasound with laser-assisted MAL-PDT with short incubation time for field cancerization had not been reported before.

Ultrafast temporal-spatial dynamics of amorphous-to-crystalline phase transition in Ge2Sb2Te5 thin film triggered by multiple femtosecond laser pulses irradiation.

Studies have shown that the crystallization phase state of Ge2Sb2Te5 (GST) can be reversibly modulated by femtosecond (fs) laser multiple pulses, which have excellent applications in reconfigurable multilevel operation fields. In this study, the temporal-spatial crystalline evolution dynamics of amorphous GST film is investigated during two fs laser pulses excitation through a pump-probe shadowgraph imaging technique. A quasi-amorphous phase state, which is different from that in the initial as-deposited am...


Quick Search