Displaying publications 21 - 40 of 89 in total

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  1. Laboratory study of acoustic velocity in different types of rocks at seismic frequency band
    Suping Peng, Wenfeng Du, Xiaoming Tang, Zeng Hu, Yunlan He
    Sains Malaysiana, 2017;46:2187-2193.
    In order to understand the characteristics of acoustic wave propagation in rocks within seismic frequency band (<100
    Hz), the velocities of longitudinal and transverse waves of four different types of rocks were tested using low-frequency
    stress-strain method by means of the physical testing system of rock at low frequency and the experimental data of acoustic
    velocities of four different types of rocks at this frequency band were obtained. The experimental results showed that the
    acoustic velocities of four different types of rocks increased with the increase of temperature and pressure within the
    temperature and pressure ranges set by the experiment. The acoustic velocity of fine sandstone at 50% water saturation
    was smaller than that of dry sample. The acoustic velocities of four different types of rocks were different and the velocities
    of longitudinal waves of gritstone, fine sandstone, argillaceous siltstone and mudstone increased in turn under similar
    conditions and were smaller than those at ultrasonic frequency. Few of existing studies focus on the acoustic velocity at
    seismic frequency band, thus, further understanding of the acoustic characteristics at this seismic frequency band still
    requires more experimental data.
    Matched MeSH terms: Acoustics
  2. Lexical analyses of the function and phonology of Papuan Malay word stress
    Kaland C, Kluge A, van Heuven VJ
    Phonetica, 2021 04 27;78(2):141-168.
    PMID: 33892529 DOI: 10.1515/phon-2021-2003
    The existence of word stress in Indonesian languages has been controversial. Recent acoustic analyses of Papuan Malay suggest that this language has word stress, counter to other studies and unlike closely related languages. The current study further investigates Papuan Malay by means of lexical (non-acoustic) analyses of two different aspects of word stress. In particular, this paper reports two distribution analyses of a word corpus, 1) investigating the extent to which stress patterns may help word recognition and 2) exploring the phonological factors that predict the distribution of stress patterns. The facilitating role of stress patterns in word recognition was investigated in a lexical analysis of word embeddings. The results show that Papuan Malay word stress (potentially) helps to disambiguate words. As for stress predictors, a random forest analysis investigated the effect of multiple morpho-phonological factors on stress placement. It was found that the mid vowels /ɛ/ and /ɔ/ play a central role in stress placement, refining the conclusions of previous work that mainly focused on /ɛ/. The current study confirms that non-acoustic research on stress can complement acoustic research in important ways. Crucially, the combined findings on stress in Papuan Malay so far give rise to an integrated perspective to word stress, in which phonetic, phonological and cognitive factors are considered.
    Matched MeSH terms: Acoustics
  3. Fulltext Impact of cavitation on the structure and functional quality of extracted protein from food sources - An overview
    Kamal H, Ali A, Manickam S, Le CF
    Food Chem, 2023 May 01;407:135071.
    PMID: 36493478 DOI: 10.1016/j.foodchem.2022.135071
    Increasing protein demands directly require additional resources to those presently and recurrently available. Emerging green technologies have witnessed an escalating interest in "Cavitation Processing" (CP) to ensure a non-invasive, non-ionizing and non-polluting extraction. The main intent of this review is to present an integrated summary of cavitation extraction methods specifically applied to food protein sources. Along with a comparative assessment carried out for each type of cavitation model, protein extraction yield and implications on the extracted protein's structural and functional properties. The basic principle of cavitation is due to the pressure shift in the liquid flow within milliseconds. Hence, cavitation emerges similar to boiling; however, unlike boiling (temperature change), cavitation occurs due to pressure change. Characterization and classification of sample type is also a prime candidate when considering the applications of cavitation models in food processing. Generally, acoustic and hydrodynamic cavitation is applied in food applications including extraction, brewing, microbial cell disruption, dairy processing, emulsification, fermentation, waste processing, crystallisation, mass transfer and production of bioactive peptides. Micro structural studies indicate that shear stress causes disintegration of hydrogen bonds and Van der Waals interactions result in the unfolding of the protein's secondary and/or tertiary structures. A change in the structure is not targeted but rather holistic and affects the physicochemical, functional, and nutritional properties. Cavitation assisted extraction of protein is typically studied at a laboratory scale. This highlights limitations against the application at an industrial scale to obtain potential commercial gains.
    Matched MeSH terms: Acoustics
  4. Fulltext ChiroVox: a public library of bat calls
    Görföl T, Huang JC, Csorba G, Győrössy D, Estók P, Kingston T, et al.
    PeerJ, 2022;10:e12445.
    PMID: 35070499 DOI: 10.7717/peerj.12445
    Recordings of bat echolocation and social calls are used for many research purposes from ecological studies to taxonomy. Effective use of these relies on identification of species from the recordings, but comparative recordings or detailed call descriptions to support identification are often lacking for areas with high biodiversity. The ChiroVox website (https://www.chirovox.org) was created to facilitate the sharing of bat sound recordings together with their metadata, including biodiversity data and recording circumstances. To date, more than 30 researchers have contributed over 3,900 recordings of nearly 200 species, making ChiroVox the largest open-access bat call library currently available. Each recording has a unique identifier that can be cited in publications; hence the acoustic analyses are repeatable. Most of the recordings available through the website are from bats whose species identities are confirmed, so they can be used to determine species in recordings where the bats were not captured or could not be identified. We hope that with the help of the bat researcher community, the website will grow rapidly and will serve as a solid source for bat acoustic research and monitoring.
    Matched MeSH terms: Acoustics
  5. Fulltext Applications and advances in acoustic monitoring for infectious disease epidemiology
    Johnson E, Campos-Cerqueira M, Jumail A, Yusni ASA, Salgado-Lynn M, Fornace K
    Trends Parasitol, 2023 May;39(5):386-399.
    PMID: 36842917 DOI: 10.1016/j.pt.2023.01.008
    Emerging infectious diseases continue to pose a significant burden on global public health, and there is a critical need to better understand transmission dynamics arising at the interface of human activity and wildlife habitats. Passive acoustic monitoring (PAM), more typically applied to questions of biodiversity and conservation, provides an opportunity to collect and analyse audio data in relative real time and at low cost. Acoustic methods are increasingly accessible, with the expansion of cloud-based computing, low-cost hardware, and machine learning approaches. Paired with purposeful experimental design, acoustic data can complement existing surveillance methods and provide a novel toolkit to investigate the key biological parameters and ecological interactions that underpin infectious disease epidemiology.
    Matched MeSH terms: Acoustics
  6. Fulltext Influence of MHz-order acoustic waves on bacterial suspensions
    Chew NSL, Ooi CW, Yeo LY, Tan MK
    Ultrasonics, 2024 Mar;138:107234.
    PMID: 38171227 DOI: 10.1016/j.ultras.2023.107234
    The development of alternative techniques to efficiently inactivate bacterial suspensions is crucial to prevent transmission of waterborne illness, particularly when commonly used techniques such as heating, filtration, chlorination, or ultraviolet treatment are not practical or feasible. We examine the effect of MHz-order acoustic wave irradiation in the form of surface acoustic waves (SAWs) on Gram-positive (Escherichia coli) and Gram-negative (Brevibacillus borstelensis and Staphylococcus aureus) bacteria suspended in water droplets. A significant increase in the relative bacterial load reduction of colony-forming units (up to 74%) can be achieved by either increasing (1) the excitation power, or, (2) the acoustic treatment duration, which we attributed to the effect of the acoustic radiation force exerted on the bacteria. Consequently, by increasing the maximum pressure amplitude via a hybrid modulation scheme involving a combination of amplitude and pulse-width modulation, we observe that the bacterial inactivation efficiency can be further increased by approximately 14%. By combining this scalable acoustic-based bacterial inactivation platform with plasma-activated water, a 100% reduction in E. coli is observed in less than 10 mins, therefore demonstrating the potential of the synergistic effects of MHz-order acoustic irradiation and plasma-activated water as an efficient strategy for water decontamination.
    Matched MeSH terms: Acoustics
  7. Fulltext Acoustic emission monitoring of multicell reinforced concrete box girders subjected to torsion
    Bagherifaez M, Behnia A, Majeed AA, Hwa Kian C
    ScientificWorldJournal, 2014;2014:567619.
    PMID: 25180203 DOI: 10.1155/2014/567619
    Reinforced concrete (RC) box girders are a common structural member for road bridges in modern construction. The hollow cross-section of a box girder is ideal in carrying eccentric loads or torques introduced by skew supports. This study employed acoustic emission (AE) monitoring on multicell RC box girder specimens subjected to laboratory-based torsion loading. Three multicell box girder specimens with different cross-sections were tested. The aim is to acquire AE analysis data indicative for characterizing torsion fracture in the box girders. It was demonstrated through appropriate parametric analysis that the AE technique could be utilized to effectively classify fracture developed in the specimens for describing their mechanical behavior under torsion. AE events localization was presented to illustrate the trend of crack and damage propagation in different stages of fracture. It could be observed that spiral-like patterns of crack were captured through AE damage localization system and damage was quantified successfully in different stages of fracture by using smoothed b-value analysis.
    Matched MeSH terms: Acoustics/instrumentation
  8. Fulltext A magnetic resonance imaging study on the articulatory and acoustic speech parameters of Malay vowels
    Zourmand A, Mirhassani SM, Ting HN, Bux SI, Ng KH, Bilgen M, et al.
    Biomed Eng Online, 2014;13:103.
    PMID: 25060583 DOI: 10.1186/1475-925X-13-103
    The phonetic properties of six Malay vowels are investigated using magnetic resonance imaging (MRI) to visualize the vocal tract in order to obtain dynamic articulatory parameters during speech production. To resolve image blurring due to the tongue movement during the scanning process, a method based on active contour extraction is used to track tongue contours. The proposed method efficiently tracks tongue contours despite the partial blurring of MRI images. Consequently, the articulatory parameters that are effectively measured as tongue movement is observed, and the specific shape of the tongue and its position for all six uttered Malay vowels are determined.Speech rehabilitation procedure demands some kind of visual perceivable prototype of speech articulation. To investigate the validity of the measured articulatory parameters based on acoustic theory of speech production, an acoustic analysis based on the uttered vowels by subjects has been performed. As the acoustic speech and articulatory parameters of uttered speech were examined, a correlation between formant frequencies and articulatory parameters was observed. The experiments reported a positive correlation between the constriction location of the tongue body and the first formant frequency, as well as a negative correlation between the constriction location of the tongue tip and the second formant frequency. The results demonstrate that the proposed method is an effective tool for the dynamic study of speech production.
    Matched MeSH terms: Acoustics*
  9. Vocal fundamental frequency and perturbation measurements of vowels by normal Malaysian Chinese adults
    Ting HN, Chia SY, Kim KS, Sim SL, Abdul Hamid B
    J Voice, 2011 Nov;25(6):e311-7.
    PMID: 21376529 DOI: 10.1016/j.jvoice.2010.05.004
    The acoustic properties of vowel phonation vary across cultures. These specific characteristics, including vowel fundamental frequency (F(0)) and perturbation measures (Absolute Jitter [Jita], Jitter [Jitt], Relative Average Perturbation [RAP], five-point Period Perturbation Quotient [PPQ5], Absolute Shimmer [ShdB], Shimmer [Shim], and 11-point Amplitude Perturbation Quotient [APQ11]) are not well established for Malaysian Chinese adults. This article investigates the F(0) and perturbation measurements of sustained vowels in 60 normal Malaysian Chinese adults using acoustical analysis. Malaysian Chinese females had significantly higher F(0) than Malaysian males in all six vowels. However, there were no significant differences in F(0) across the vowels for each gender. Significant differences between vowels were observed for Jita, Jitt, PPQ5, ShdB, Shim, and APQ11 among Chinese males, whereas significant differences between vowels were observed for all the perturbation parameters among Chinese females. Chinese males had significantly higher Jita and APQ11 in the vowels than Chinese females, whereas no significant differences were observed between males and females for Jitt, RAP, PPQ5, and Shim. Cross-ethnic comparisons indicate that F(0) of vowel phonation varies within the Chinese ethnic group and across other ethnic groups. The perturbation measures cannot be simply compared, where the measures may vary significantly across different speech analysis softwares.
    Matched MeSH terms: Speech Acoustics*
  10. A direction-sensitive underwater blast detector and its application for managing blast fishing
    Woodman GH, Wilson SC, Li VY, Renneberg R
    Mar Pollut Bull, 2004 Dec;49(11-12):964-73.
    PMID: 15556182
    Little is known about the spatial and temporal distribution of blast fishing which hampers enforcement against this activity. We have demonstrated that a triangular array of hydrophones 1 m apart is capable of detecting blast events whilst effectively rejecting other sources of underwater noise such as snapping shrimp and nearby boat propellers. A total of 13 blasts were recorded in Sepangor bay, North of Kota Kinabalu, Sabah, Malaysia from 7th to 15th July 2002 at distances estimated to be up to 20 km, with a directional uncertainty of 0.2 degrees . With such precision, a network of similar hydrophone arrays has potential to locate individual blast events by triangulation to within 30 m at a range of 10 km.
    Matched MeSH terms: Acoustics/instrumentation*
  11. Direct airborne acoustic wave modulation of Fabry-Perot fiber laser (FPFL) over 100 kHz of operating bandwidth
    Pua CH, Ahmad H, Harun SW, De La Rue RM
    Appl Opt, 2012 May 20;51(15):2772-7.
    PMID: 22614578 DOI: 10.1364/AO.51.002772
    The idea of applying a simple Fabry-Perot fiber laser (FPFL) set-up in a free-running condition as an acoustic sensing medium is proposed. Conventional optical microphone requires a stringently aligned diaphragm to mediate the acoustic impedance mismatch between air and silica fiber. Motivated by the difficulty of optical sensing of airborne acoustic waves, a new sensing method is proposed to sense acoustic waves without the assistance of a diaphragm as transducer. By studying the output power fluctuation of the FPFL, the operating bandwidth and sensitivity of the proposed sensing method are determined. The tunability of the resonant frequency from 5 kHz to 85 kHz allows sensing of acoustic waves in the range of 100 Hz to 100 kHz. Tuning of the resonant frequency can be performed by changing the optical pumping power from as low as 10 mW to 68.5 mW or higher.
    Matched MeSH terms: Acoustics
  12. Fulltext Low-Slow-Small (LSS) Target Detection Based on Micro Doppler Analysis in Forward Scattering Radar Geometry
    Musa SA, Raja Abdullah RSA, Sali A, Ismail A, Rashid NEA
    Sensors (Basel), 2019 Jul 29;19(15).
    PMID: 31362452 DOI: 10.3390/s19153332
    The increase in drone misuse by civilian apart from military applications is alarming and need to be addressed. This drone is characterized as a low altitude, slow speed, and small radar cross-section (RCS) (LSS) target and is considered difficult to be detected and classified among other biological targets, such as insects and birds existing in the same surveillance volume. Although several attempts reported the successful drone detection on radio frequency-based (RF), thermal, acoustic, video imaging, and other non-technical methods, however, there are also many limitations. Thus, this paper investigated a micro-Doppler analysis from drone rotating blades for detection in a special Forward Scattering Radar (FSR) geometry. The paper leveraged the identified benefits of FSR mode over conventional radars, such as improved radar cross-section (RCS) value irrespective of radar absorbing material (RAM), direct signal perturbation, and high resolutions. To prove the concept, a received signal model for micro-Doppler analysis, a simulation work, and experimental validation are elaborated and explained in the paper. Two rotating blades aspect angle scenarios were considered, which are (i) when drone makes a turn, the blade cross-sectional area faces the receiver and (ii) when drone maneuvers normally, the cross-sectional blade faces up. The FSR system successfully detected a commercial drone and extracted the micro features of a rotating blade. It further verified the feasibility of using a parabolic dish antenna as a receiver in FSR geometry; this marked an appreciable achievement towards the FSR system performance, which in future could be implemented as either active or passive FSR system.
    Matched MeSH terms: Acoustics
  13. Digital noise reduction in hearing aids and its acoustic effect on consonants /s/ and /z/
    Chong FY, Jenstad LM
    Med J Malaysia, 2018 12;73(6):365-370.
    PMID: 30647205
    INTRODUCTION: Modulation-based noise reduction (MBNR) is one of the common noise reduction methods used in hearing aids. Gain reduction in high frequency bands may occur for some implementations of MBNR and fricatives might be susceptible to alteration, given the high frequency components in fricative noise. The main objective of this study is to quantify the acoustic effect of MBNR on /s, z/.

    METHODS: Speech-and-noise signals were presented to, and recorded from, six hearing aids mounted on a head and torso simulator. Test stimuli were nonsense words mixed with pink, cafeteria, or speech-modulated noise at 0 dB SNR. Fricatives /s, z/ were extracted from the recordings for analysis.

    RESULTS: Analysis of the noise confirmed that MBNR in all hearing aids was activated for the recordings. More than 1.0 dB of acoustic change occurred to /s, z/ when MBNR was turned on in four out of the six hearing aids in the pink and cafeteria noise conditions. The acoustics of /s, z/ by female talkers were affected more than male talkers. Significant relationships between amount of noise reduction and acoustic change of /s, z/ were found. Amount of noise reduction accounts for 42.8% and 16.8% of the variability in acoustic change for /s/ and /z/ respectively.

    CONCLUSION: Some clinically-available implementations of MBNR have measurable effects on the acoustics of fricatives. Possible implications for speech perception are discussed.

    Matched MeSH terms: Acoustics
  14. Lamb to Rayleigh Wave Conversion on Superstrates as a Means to Facilitate Disposable Acoustomicrofluidic Applications
    Wong KS, Lee L, Hung YM, Yeo LY, Tan MK
    Anal Chem, 2019 10 01;91(19):12358-12368.
    PMID: 31500406 DOI: 10.1021/acs.analchem.9b02850
    Rayleigh surface acoustic waves (SAWs) have been demonstrated as a powerful and effective means for driving a wide range of microfluidic actuation processes. Traditionally, SAWs have been generated on piezoelectric substrates, although the cost of the material and the electrode deposition process makes them less amenable as low-cost and disposable components. As such, a "razor-and-blades" model that couples the acoustic energy of the SAW on the piezoelectric substrate through a fluid coupling layer and into a low-cost and, hence, disposable silicon superstrate on which various microfluidic processes can be conducted has been proposed. Nevertheless, it was shown that only bulk vibration in the form of Lamb waves can be excited in the superstrate, which is considerably less efficient and flexible in terms of microfluidic functionality compared to its surface counterpart, that is, the SAW. Here, we reveal an extremely simple way that quite unexpectedly and rather nonintuitively allows SAWs to be generated on the superstrate-by coating the superstrate with a thin gold layer. In addition to verifying the existence of the SAW on the coated superstrate, we carry out finite-difference time domain numerical simulations that not only confirm the experimental observations but also facilitate an understanding of the surprising difference that the coating makes. Finally, we elucidate the various power-dependent particle concentration phenomena that can be carried out in a sessile droplet atop the superstrate and show the possibility for simply carrying out rapid and effective microcentrifugation-a process that is considerably more difficult with Lamb wave excitation on the superstrate.
    Matched MeSH terms: Acoustics
  15. Emotional speech acoustic model for Malay: iterative versus isolated unit training
    Mustafa MB, Ainon RN
    J Acoust Soc Am, 2013 Oct;134(4):3057-66.
    PMID: 24116440 DOI: 10.1121/1.4818741
    The ability of speech synthesis system to synthesize emotional speech enhances the user's experience when using this kind of system and its related applications. However, the development of an emotional speech synthesis system is a daunting task in view of the complexity of human emotional speech. The more recent state-of-the-art speech synthesis systems, such as the one based on hidden Markov models, can synthesize emotional speech with acceptable naturalness with the use of a good emotional speech acoustic model. However, building an emotional speech acoustic model requires adequate resources including segment-phonetic labels of emotional speech, which is a problem for many under-resourced languages, including Malay. This research shows how it is possible to build an emotional speech acoustic model for Malay with minimal resources. To achieve this objective, two forms of initialization methods were considered: iterative training using the deterministic annealing expectation maximization algorithm and the isolated unit training. The seed model for the automatic segmentation is a neutral speech acoustic model, which was transformed to target emotion using two transformation techniques: model adaptation and context-dependent boundary refinement. Two forms of evaluation have been performed: an objective evaluation measuring the prosody error and a listening evaluation to measure the naturalness of the synthesized emotional speech.
    Matched MeSH terms: Acoustics*; Speech Acoustics*
  16. Fulltext An Inventory of Vowel Phonemes of the Melanau Rajang dialect
    MARINA KAWI, DAYANG SARIAH ABANG SUHAI
    Trends in Undergraduate Research, 2018;1(1):0-0.
    MyJurnal
    The study aims to identify an inventory of vowel phonemes of Melanau Rajang dialect in Belawai under the administration of Tanjung Manis District, Sarawak. This study is a field survey using interview methods to obtain data. A total 250 Swadesh list (Samarin, 1967) are used as a guide for data collection. In this study, two infotmants of different genders aged between 40 and 60 years old were selected based on criteria of informant selections according to Asmah Haji Omar (2001). In analysis data, qualitative method is used based on structural approaches. The findings show that there are eight (8) vowel phonemes have been identified; four (4) front vowels [i, e, ε, a]; one (1) central vowel [ə]; and three (3) back vowels [u, o, ɔ]. Besides that, the distribution/alternation of all vowel phonemes of Melanau Rajang dialect in Belawai are also discussed in this study. The findings also indicate that active vowel phonemes are vowels [a, i, u], while inactive vocal phonemes are vowels [ɔ, o, ε, ə, e].
    Matched MeSH terms: Speech Acoustics
  17. Fulltext Effect of sea-bottom elasticity on the propagation of acoustic-gravity waves from impacting objects
    Kadri U
    Sci Rep, 2019 Jan 29;9(1):912.
    PMID: 30696934 DOI: 10.1038/s41598-018-37626-z
    Recent analysis of data, recorded on March 8th 2014 at the Comprehensive Nuclear-Test-Ban Treaty Organisation's hydroacoustic stations off Cape Leeuwin Western Australia, and at Diego Garcia, has led to the development of an inverse model for locating impacting objects on the sea surface. The model employs the phase velocity of acoustic-gravity waves that radiate during the impact, and only considers their propagation in the water layer. Here, we address a significant characteristic of acoustic-gravity waves: the ability to penetrate through the sea-bottom, which modifies the propagation speed and thus the arrival time of signals at the hydrophone station. Therefore, we revisit some signals that are associated with the missing Malaysian Aeroplane MH370, and illustrate the role of sea-bottom elasticity on determining impact locations.
    Matched MeSH terms: Acoustics
  18. Fulltext Game Theory-Based Cooperation for Underwater Acoustic Sensor Networks: Taxonomy, Review, Research Challenges and Directions
    Muhammed D, Anisi MH, Zareei M, Vargas-Rosales C, Khan A
    Sensors (Basel), 2018 Feb 01;18(2).
    PMID: 29389874 DOI: 10.3390/s18020425
    Exploring and monitoring the underwater world using underwater sensors is drawing a lot of attention these days. In this field cooperation between acoustic sensor nodes has been a critical problem due to the challenging features such as acoustic channel failure (sound signal), long propagation delay of acoustic signal, limited bandwidth and loss of connectivity. There are several proposed methods to improve cooperation between the nodes by incorporating information/game theory in the node's cooperation. However, there is a need to classify the existing works and demonstrate their performance in addressing the cooperation issue. In this paper, we have conducted a review to investigate various factors affecting cooperation in underwater acoustic sensor networks. We study various cooperation techniques used for underwater acoustic sensor networks from different perspectives, with a concentration on communication reliability, energy consumption, and security and present a taxonomy for underwater cooperation. Moreover, we further review how the game theory can be applied to make the nodes cooperate with each other. We further analyze different cooperative game methods, where their performance on different metrics is compared. Finally, open issues and future research direction in underwater acoustic sensor networks are highlighted.
    Matched MeSH terms: Acoustics
  19. A computational framework for the multiphysics simulation of microbubble-mediated sonothrombolysis using a forward-viewing intravascular transducer
    Tan ZQ, Ooi EH, Chiew YS, Foo JJ, Ng EYK, Ooi ET
    Ultrasonics, 2023 May;131:106961.
    PMID: 36812819 DOI: 10.1016/j.ultras.2023.106961
    Sonothrombolysis is a technique that utilises ultrasound waves to excite microbubbles surrounding a clot. Clot lysis is achieved through mechanical damage induced by acoustic cavitation and through local clot displacement induced by acoustic radiation force (ARF). Despite the potential of microbubble-mediated sonothrombolysis, the selection of the optimal ultrasound and microbubble parameters remains a challenge. Existing experimental studies are not able to provide a complete picture of how ultrasound and microbubble characteristics influence the outcome of sonothrombolysis. Likewise, computational studies have not been applied in detail in the context of sonothrombolysis. Hence, the effect of interaction between the bubble dynamics and acoustic propagation on the acoustic streaming and clot deformation remains unclear. In the present study, we report for the first time the computational framework that couples the bubble dynamic phenomena with the acoustic propagation in a bubbly medium to simulate microbubble-mediated sonothrombolysis using a forward-viewing transducer. The computational framework was used to investigate the effects of ultrasound properties (pressure and frequency) and microbubble characteristics (radius and concentration) on the outcome of sonothrombolysis. Four major findings were obtained from the simulation results: (i) ultrasound pressure plays the most dominant role over all the other parameters in affecting the bubble dynamics, acoustic attenuation, ARF, acoustic streaming, and clot displacement, (ii) smaller microbubbles could contribute to a more violent oscillation and improve the ARF simultaneously when they are stimulated at higher ultrasound pressure, (iii) higher microbubbles concentration increases the ARF, and (iv) the effect of ultrasound frequency on acoustic attenuation is dependent on the ultrasound pressure. These results may provide fundamental insight that is crucial in bringing sonothrombolysis closer to clinical implementation.
    Matched MeSH terms: Acoustics
  20. Acoustic evaluation of photobiomodulation effect on in vitro human blood samples
    Suardi N, Germanam SJ, Rahim NAYM
    Lasers Med Sci, 2023 Apr 14;38(1):99.
    PMID: 37059895 DOI: 10.1007/s10103-023-03766-6
    Although positive photobiomodulation response on wound healing, tissue repair, and therapeutic treatment has been widely reported, additional works are still needed to understand its effects on human blood. This research carried out acoustic measurements using A-scan (GAMPT) ultrasonic techniques to elucidate the photobiomodulation effects on in vitro human blood samples as therapeutic treatment measures. The human blood samples were irradiated using a 532-nm laser with different output laser powers (60 and 80 mW) at various exposure times. The ultrasonic velocity measured in the human blood samples after laser irradiation showed significant changes, most of which were within the acceptance limit for soft tissues (1570 [Formula: see text] 30 m/s). Abnormal cells (echinocyte and crenation) were observed due to excessive exposure during laser treatment.
    Matched MeSH terms: Acoustics
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