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A primary wideband calibration method for noise hydrophones is developed, which can be applied to obtain noise acoustic spectral density sensitivity in the free-field. In this method, a wideband three-transducer spherical wave reciprocity calibration method is proposed in the frequency domain. A lowpass spatial domain filter is utilized to eliminate the reflecting acoustic waves from boundaries and water surface, and the wideband frequency responses of the transducer pair are calculated. Wideband calibrations are performed in a laboratory anechoic water tank, and two hydrophones with different reference sensitivities are calibrated in the frequency range of 250 Hz to 20 kHz using noise signals. The decidecade band sensitivities are obtained by the primary wideband calibration, which is in agreement with the single frequency sensitivities. The expended uncertainty of the primary wideband calibration is analyzed and estimated to be 8.9% (k = 2). [ABSTRACT FROM AUTHOR]

Ectropis grisescens is a notorious pest in tea plantations. The control of E. grisescens relies on synesthetic pesticides but the resurgence is always accompanied by increasing resistance. Therefore, it is crucial to use biological control to reduce the damage caused by E. grisescens. Here, we collected soil from a tea plantation, used Galleria mellonella as a bait insect and successfully isolated one entomopathogenic fungus. The isolated colony was initially identified as Cordyceps sp. using morphological observation. ITS‐rDNA sequence amplification and sequencing, molecular database comparisons, and phylogenetic analysis proved this fungus as a new species and thus named Cordyceps sp. WZFW1. Further virulence test of Cordyceps sp. WZFW1 against E. grisescens was evaluated under laboratory conditions. Lethal concentration was 5.74 × 106 spore/mL with a confidence level of 2.32 × 106 ~ 1.79 × 107 and lethal time was 2.98 days at 108 spore/mL and 7.47 days at 107 spore/mL, indicating Cordyceps sp. WZFW1 was effective at controlling E. grisescens. Our findings are significant as they contribute to the application of new entomopathogenic fungi (EPF) species as biocontrol agents, promoting eco‐friendly pest management practices. Research Highlights: A novel species, Cordyceps sp. WZFW1, was isolated from soil in a tea plantation in China. Cordyceps sp. WZFW1 caused up to 79% mortality to second‐instar Ectropis grisescens larvae after 7‐day treatment, indicating its potential in E. grisescens control. [ABSTRACT FROM AUTHOR]

As an innovative neural modulation technique, the transcranial magneto-acousto-electric (MAE) stimulation (TMAES) realizes the synergistic regulation of neuronal discharge through the ultrasonic mechanical and inductive electric effects, offering significant prospects in biomedical applications. However, the stimulation accuracy is still limited by the unidirectional distribution of MAE field intensity. A method of constructing center-converging MAE field by coupling the helical wave fronts of focused acoustic-vortex (FAV) beams with a coaxial magnetic field is proposed. By describing FAVs with Laguerre–Gaussian functions, the theory of MAE field construction is derived in explicit formulae and the spatiotemporal characteristics of MAE fields in the focal region are analyzed. It is theoretically and experimentally demonstrated that the MAE field generated by the FAV of lth order is determined by those of (l − 1)th and (l + 1)th orders. The center-converging phase-rotating MAE field can only be generated by the FAV of first order, maintaining a constant peak intensity at the vortex center. Experimental distributions of MAE fields for FAVs of different orders show good agreements with numerical simulations. With the peak pressure of 0.86 MPa and the magnetic intensity of 0.3 T, the peak intensity of 62.1 mV/m reaching the electric stimulation threshold is achieved. The center-converging MAE field constructed by FAV may develop a new synergistic neural modulation scheme for TMAES with enhanced precision and flexibility while ensuring safety and efficacy, thereby exhibiting significant scientific and practical implications. [ABSTRACT FROM AUTHOR]

Acute focal bacterial nephritis (AFBN) is a kidney disease characterized by a localized bacterial infection that manifests as an inflammatory mass. Most children with AFBN have nonspecific symptoms including fever, vomiting, and abdominal discomfort, and some develop neurological symptoms such as meningeal irritation, unconsciousness, and seizures as their condition worsens. This was 2 cases of AFBN with central nervous system manifestations in children, and we analyzed its possible mechanisms of the clinical and radiographic features. We experience 2 very unusual cases of AFBN which were linked to central nervous system abnormalities. A 6-year-old boy with AFBN and clinically moderate ncephalitis/encephalopathy with a reversible splenial lesion (MERS) presented with neurological symptoms, including unconsciousness and convulsions. The second case involved an 8-year-old child with AFBN-associated acute encephalopathy who exhibited neurological symptoms, including unconsciousness. According to previous research, AFBN is linked to central nervous system impairment. As a result, when a clinician meets a patient with an inexplicable fever caused by a neurological condition, he should pay attention to this diagnosis of AFBN and follow it in the abdominal graph. [ABSTRACT FROM AUTHOR]

Multi-parameter fitting algorithms, which are currently used for the characterization of coated-bubbles, inevitably introduce uncertainty into the results. Therefore, a better technique that can accurately determine the microbubbles׳ mechanical properties is urgently needed. A comprehensive technology combining atomic force microscopy, optical, and acoustic measurements with simulations of coated-bubble dynamics was developed. Using this technique, the mechanical parameters (size distribution, shell thickness, elasticity, and viscosity) of hybrid (ultrasound/magnetic-resonance-imaging) contrast microbubbles and their structure–property relationship were determined. The measurements indicate that when more superparamagnetic iron oxide nanoparticles are embedded in the microbubbles׳ shells, their mean diameter and effective viscosity increase, and their elastic modulus decreases. This reduces the microbubbles׳ resonance frequency and thus enhances acoustic scattering and attenuation effects. [ABSTRACT FROM AUTHOR]

The aluminum foil erosion method is widely used in cavitation activity studies of ultrasonic cleaners. However, owing to its limited sensitivity, it is difficult to observe the effects of various experimental parameters on the cavitation activity using this method. In the present work, a higher-sensitivity method for quantifying cavitation activity as a cavitation dose based on passive cavitation detection was presented. The influences of various factors (e.g., insonation duration, driving power, gas content, temperature and cleaning agents) were studied for this system. The results showed that the cavitation dose became unstable over long insonation times, and that the instability was more significant at high power. Generally, the cavitation activity could be enhanced by increasing the power, gas content, and the concentration of a cleaning agent. However, due to the exhaustion of the cavitation gas nuclei, the cavitation activity might tune to saturate of even decrease slightly when some impact parameters (e.g., acoustic driving power, gas content and the concentration of the cleaning agent) are above a certain level of each of these parameters. [ABSTRACT FROM AUTHOR]

Wilson's disease (WD) is an autosomal recessive disorder, and has a variety of presentations. We reported a case of 9-year-old girl who presented with a history of recurrent gross hematuria, renal histological changes of IgA nephropathy, and finally had been confirmed to be Wilson's disease-associated IgA nephropathy. [ABSTRACT FROM AUTHOR]

High intensity focused ultrasound (HIFU)-induced hyperthermia is a promising tool for cancer therapy. Three-dimensional nonlinear acoustic-bioheat transfer-blood flow-coupling model simulations and in vivo thermocouple measurements were performed to study hyperthermia effects in rabbit auricular vein exposed to pulsed HIFU (pHIFU) at varied duty cycles (DCs). pHIFU-induced temperature elevations are shown to increase with increasing DC. A critical DC of 6.9% is estimated for temperature at distal vessel wall exceeding 44 °C, although different tissue depths and inclusions could affect the DC threshold. The results demonstrate clinic potentials of achieving controllable hyperthermia by adjusting pHIFU DCs, while minimizing perivascular thermal injury. [ABSTRACT FROM AUTHOR]

Hyperthermia effects (39-44 °C) induced by pulsed high-intensity focused ultrasound (HIFU) have been regarded as a promising therapeutic tool for boosting immune responses or enhancing drug delivery into a solid tumor. However, previous studies also reported that the cell death occurs when cells are maintained at 43 °C for more than 20 minutes. The aim of this study is to investigate thermal responses inside in vivo rabbit auricular veins exposed to pulsed HIFU (1.17 MHz, 5300 W/cm2, with relatively low-duty ratios (0.2%-4.3%). The results show that: (1) with constant pulse repetition frequency (PRF) (e.g., 1 Hz), the thermal responses inside the vessel will increase with the increasing duty ratio; (2) a temperature elevation to 43 °C can be identified at the duty ratio of 4.3%; (3) with constant duty ratios, the change of PRF will not significantly affect the temperature measurement in the vessel; (4) as the duty ratios lower than 4.3%, the presence of microbubbles will not significantly enhance the thermal responses in the vessel, but will facilitate HIFU-induced inertial cavitation events. [ABSTRACT FROM AUTHOR]

The dynamic behaviour of SonoVue microbubbles, a new generation ultrasound contrast agent, is investigated in real time with light scattering method. Highly diluted SonoVue microbubbles are injected into a diluted gel made of xanthan gum and water. The responses of individual SonoVue bubbles to driven ultrasound pulses are measured. Both linear and nonlinear bubble oscillations are observed and the results suggest that SonoVue microbubbles can generate strong nonlinear responses. By fitting the experimental data of individual bubble responses with Sarkar's model, the shell coating parameter of the bubbles and dilatational viscosity is estimated to be 7.0 nm*s*Pa. [ABSTRACT FROM AUTHOR]

Abstract: Previous in vivo studies have demonstrated that vascular endothelial damage can result when vessels containing gas-based microbubble ultrasound contrast agent (UCA) are exposed to MHz-frequency pulsed ultrasound (US) of sufficient pressure amplitudes, presumably as a result of inertial cavitation (IC). The hypothesis guiding this research was that IC is the primary mechanism by which the vascular endothelium (VE) is damaged when a vessel is exposed to pulsed 1-MHz frequency US in the presence of circulating UCA. The expectation was that a correlation should exist between the magnitude and duration of IC activity and the degree of VE damage. Rabbit auricular vessels were exposed in vivo to 1.17-MHz focused US of variable peak rarefaction pressure amplitude (1, 3, 6.5 or 9 MPa), using low duty factors (0.04% or 0.4%), pulse lengths of 500 or 5000 cycles, with varying treatment durations and with or without infusion of a shelled microbubble contrast agent. A broadband passive cavitation detection system was used to measure IC activity in vivo within the targeted segment of the blood vessel. The magnitude of the detected IC activity was quantified using a previously reported measure of IC dose. Endothelial damage was assessed via scanning electron microscopy image analysis. The results supported the hypothesis and demonstrate that the magnitude of the measured IC dose correlates with the degree of VE damage when UCA is present. These results have implications for therapeutic US-induced vascular occlusion. (E-mail: jooha@u.washington.edu) [Copyright &y& Elsevier]

Abstract: Inertial cavitation (IC) is an important mechanism by which ultrasound (US)-induced bioeffects can be produced. It has been reported that US-induced in vitro mechanical bioeffects with the presence of ultrasound contrast agents (UCAs) are highly correlated with quantified IC “dose” (ICD: cumulated root-mean-squared broadband noise amplitude in the frequency domain). The ICD has also been used to quantify IC activity in ex vivo perfused rabbit ear vessels. The in vivo experiments reported here using a rabbit ear vessel model were designed to: (1) detect and quantify IC activity in vivo within the constrained environment of rabbit auricular veins with the presence of Optison and (2) measure the temporal evolution of microbubble IC activity and the ICD generated during insonation treatment, as a function of acoustic parameters. Preselected regions-of-interest (ROI) in the rabbit ear vein were exposed to pulsed focused US (1.17 MHz, 1 Hz PRF). Experimental acoustic variables included peak rarefaction pressure amplitude ([PRPA]: 1.1, 3.0, 6.5 or 9.0 MPa) and pulse length (20, 100, 500 or 1000 cycles). ICD was quantified based on passive cavitation detection (PCD) measurements. The results show that: (1) after Optison injection, the time to onset of measurable microbubble IC activity was relatively consistent, approximately 20 s; (2) after reaching its peak value, the IC activity decayed exponentially and the half-life decay coefficient (t1/2) increased with increasing PRPA and pulse length; and (3) the normalized ICD generated by pulsed US exposure increased significantly with increasing PRPA and pulse length. (E-mail: juantu@u.washington.edu) [Copyright &y& Elsevier]

Abstract: Previous in vitro studies have shown that ultrasound-induced mechanical bioeffects with contrast agents present are highly correlated with inertial cavitation (IC) “dose” (). The ex vivo experiments conducted here addressed the following hypotheses: 1. IC activity can be generated by insonating perfused rabbit ear blood vessel, and 2. the IC “dose” developed during insonation treatment can be reliably measured and will vary with varying acoustic parameters and Optison® concentration. Ex vivo rabbit auricular arteries were perfused with Optison® suspensions and then exposed to 1.1-MHz pulsed focused ultrasound. Experimental variables included peak negative acoustic pressure (0.2 MPa to 5.2 MPa), pulse-repetition frequency (5, 50 or 500 Hz), pulse length (50, 100, 500 or 1000 cycles), and Optison® volume concentration (0, 0.2, 0.5 or 1%). Cavitation activity was quantified as IC dose, based on passive cavitation detection measurements. The results show that: 1. The IC pressure threshold decreases with higher concentrations of Optison®, and 2. IC dose increases significantly with increasing acoustic pressure, Optison® concentration, pulse length or with decreasing pulse-repetition frequency. (E-mail: juantu@u.washington.edu) [Copyright &y& Elsevier]

This Letter investigates the spatiotemporal evolution from a pair of like polarity solitons to chaos. We reported a particular top oscillation phenomenon occurring during the evolution which has not been noticed in previous work. The experimental observation and the numerical calculation agree with each other qualitatively. [Copyright &y& Elsevier]

The regional boom in digital economy has provided people with remote conversations and socialization while reducing the risk of depression. This study aims to elucidate whether regional digital economy can be a savior for individual depression. The multi-source dataset collects 11,845 individuals from the China Health and Retirement Longitudinal Study 2018 (CHARLS), with the combination of corresponding regional data from China City Statistical Yearbooks. A series of regressions with integrated mediation and moderation analyses are employed to bridge the link between the digital economy and depression. The results suggest that people living in areas with a higher level of digital economy are less likely to suffer from depression. The development of the digital economy helps people find solace or air grievances more easily, thereby reducing the risk of depression. Individual information and communications technology (ICT) engagement is found to mediate the relationship between the regional digital economy and individual depression. Residence type moderates the association between the three casual pairs of digital economy, ICT engagement, and depression. Improved digitization stimulates personal engagement with ICTs, which in turn expands social connections and support. Strengthened social interactions naturally keep depression away. Moreover, the urban-rural differences further confirm the underlying mechanism. Properly embracing the new digital world can therefore benefit from the transformative potential and mitigate depressive outcomes. • This study empirically examines the impacts of regional digital economy on individual depression risk. • Enhanced digitization boosts ICT use, expanding social connections and support, which naturally helps reduce depression. • The urban-rural differences moderate the associations among digital economy, ICT engagement, and depression. [ABSTRACT FROM AUTHOR]

Owing to the dense extracellular matrix and high interstitial fluid pressure in the tumor microenvironment, methods which enhance the permeation and retention of nano drugs into liver tumors remain unsatisfactory for successful tumor treatment. We designed a near-infrared (NIR)- and ultrasound (US)-triggered Pt/Pd-engineered "cluster bomb" (Pt/Pd-CB) which actively penetrates liver cancer cell membranes and achieves photothermal and sonodynamic therapy (SDT). The physical forces generated by the fast expansion and collapse of perfluoropentane nanodroplets eject "sub bombs" (Pt/Pd nanoalloys) into liver cancer cells upon activation by NIR and US. Pt/Pd nanoalloys can then convert H 2 O 2 into O 2 to alleviate hypoxia and boost SDT efficiency while exhibiting a highly efficient photothermal response under NIR irradiation. Our findings might especially be promising for the treatment of solid tumors. [Display omitted] [ABSTRACT FROM AUTHOR]

The purpose of this study is to evaluate the efficacy and safety of belimumab combined with the standard regimen in treating children with active lupus nephritis. This single-center, retrospective cohort study used clinical data of children with newly active lupus nephritis hospitalized in the Department of Nephrology between December 2004 and February 2023. Patients were divided into a belimumab or traditional treatment group according to whether or not they received belimumab. Renal remission and recurrence rates and glucocorticoid dose were compared between groups. Forty-seven children (median age 11 years) were enrolled, including 30 and 17 children in the traditional treatment and belimumab groups, respectively. The Systemic Lupus Erythematosus Disease Activity Index-2000 (SLEDAI-2000) score of children in the belimumab group (23.59 ± 7.78) was higher than that in the traditional treatment group (19.13 ± 6.10) (P = 0.035). The two groups showed no significant difference in the frequency of pyuria, gross hematuria, and the levels of 24-h proteinuria and estimated glomerular filtration rate. The complement C3/C4 in the belimumab group recovered faster than that in the traditional treatment group (P < 0.05). There were no between-group differences in the complete renal remission rate at 6 or 12 months (P = 0.442, P = 0.759). There were no between-group differences in 1-year recurrence rate (P = 0.303). Furthermore, 6 and 12 months after treatment, glucocorticoid doses were lower in the belimumab than the traditional treatment group (17.87 ± 6.96 mg/d vs. 27.33 ± 8.40 mg/d, P = 0.000; 10.00 (5.3) mg/d vs. 13.75 (10.0) mg/d, P = 0.007), respectively. Conclusion: With an equivalent renal remission rate, belimumab combined with the standard traditional regimen might promote the tapering of glucocorticoids, and the incidence of adverse events is low. What is known: • Belimumab is documented as an adjunctive treatment with systemic lupus erythematosus (c-SLE) LN with efficacy. • Due to the paucity of studies, its effects and side effects in children with LN remain unclear. What is new: • This single-center, retrospective cohort study evaluated the efficacy and safety of belimumab combined with the standard regimen in treating children with proliferative LN. • Belimumab combined with the standard traditional treatment might promote the tapering of glucocorticoids, while exhibiting a low occurrence of adverse events. [ABSTRACT FROM AUTHOR]

Depression is a relevant mental illness affecting hundreds of millions of people worldwide. As urbanization accelerates, agglomeration of populations has altered individual social network distances and life crowding, which in turn affects depressive prevalence. However, the association between depression and population agglomeration (PA) remains controversial. This study aims to explore whether and how PA could influence individual depression. Based on the China Health and Retirement Longitudinal Study (CHARLS) 2018, the empirical results showed that there was a U-shaped association between PA and individual CES-D scores. As PA increases, the risk of depression first decreases and then increases. CES-D was lowest at moderate aggregation. Dialect diversity (DD) was positively related to the incidence of individual depression. The higher the DD, the higher the risk of depression. Meanwhile, DD also played a moderating role in the association between PA and individual depression. Our observations suggest that the optimistic level of agglomeration for individual mental health is within 1500 to 2000 persons per square kilometer. [ABSTRACT FROM AUTHOR]

The article presents a case a study of a 9-year-old girl who was admitted to the hospital due to gross hematuria without any other complaints. Information about her perinatal history, past medical history, and family historyis mentioned. Also mentioned is the patient's urinary analysis, blood tests and urinary protein excretion.

Rapid urbanization is a major trend in global population migration. There is growing debate about whether this urban-rural disparity exacerbate depression at the individual level. This study aims to investigate how urban living has a beneficial impact on individual mental health. Based on the data of 15,764 participants in the 2018 China Health and Retirement Longitudinal Study (CHARLS), we perform analysis of variance to identify the gap in depression levels between urban and rural areas. Extensive comparisons and detailed statistical analyses are carried out to demonstrate the differences in social participation between urban and rural residents. Finally, we conduct a series of mediation and moderation analyses to reveal the underlying mechanisms of depressive disorder benefits of cities. The results indicate that those who lived in urban areas were less likely to suffer from depression (β = −1.461, 95 % CI = [−1.691, −1.235], p < 0.001). Social engagement is found to mediate the relationship between residence type (β = 0.164, 95 % CI = [0.136, 0.193], p < 0.001) and individual depression (β = −0.462, 95 % CI = [−0.587, −0.337], p < 0.001). City size plays a moderating role in the association between urban living and social engagement. The mechanism is conducted through cross-sectional data. Self-reported depression status is accessed in this study, which could lead to measurement error. This study demonstrates the beneficial effects of urban living on individual depression, and reveals the mechanism by which urbanization at different scales affects the prevalence of depression. • This study fueled the debate about depressive disorder from growing cities with a nationwide empirical analysis. • We identified the underlying mechanism by which urban living could protect residents from the obnoxious depression. • Our observation also revealed the contingency of the protective effect of cities against depression. [ABSTRACT FROM AUTHOR]

Based on the acoustic radiation of point source, a phase-coded approach is proposed as a general technology to generate controllable acoustical vortices. For N sources, acoustical vortices can be generated with the phase difference of 2πm/N for the source topological charge m. It is proved that more circular pressure distributions of acoustical vortices with higher pressure peak amplitude can be generated for more sources. The number and spiral direction of phase twists are demonstrated to be determined by m and the maximum topological charge of acoustical vortices is |L|=Fix[(N-1)/2], where Fix(x) rounds the element x toward zero. To produce acoustical vortices with a maximum topological charge L, the minimum source number of Nmin=max(2|L|+1,4) should be employed with the phase difference of 2πL/Nmin and the phase difference resolution is also demonstrated to be π. The phase-coded approach has been verified by a 6-source experiment. The measured distributions of pressure and phase as well as the topological charge of acoustical vortices agree well with theoretical results, which suggest the feasibility of the phase-coded approach for controllable generation of acoustical vortices. [ABSTRACT FROM AUTHOR]

Contactless manipulation of hard-to-reach objects, especially those behind obstacles, is highly demanded in many applications. In this work, auto-focusing acoustic-vortex (A-FAV) tweezers are developed based on-axis-symmetrically arranged and azimuthally phase-coded Half-Bessel (HB) beams, which can self-bend themselves along an arc-shaped trajectory and, hence, circumvent obstacles that are located on the beam path. To build such tweezers, active phase control and passive binary phase modulation for a simplified ring-array of sectorial planar transducers are integrated to build A-FAV beams of arbitrary order. Both theoretical and experimental results prove that the zero-force of A-FAV tweezers enables the stable object manipulation at the focus with improved axial and radial resolutions. Benefiting from the non-diffracting self-bending of HB beams, the enclosed bullet-shaped cavity whose inside pressure is close-to-zero can be created around the beam axis, defining the upper size limit of obstacles that can be bypassed. Moreover, A-FAV beams are capable of self-healing even parts of the mainlobes that are blocked. More importantly, the A-FAV tweezer with an obstacle-circumvention cavity is easily adjustable, exhibiting prosperous perspectives in obstacle-avoidant ultrasound imaging, ultrasound therapy, acoustic levitation, and object manipulation. [ABSTRACT FROM AUTHOR]

As a special kind of tweezers, the acoustic-vortex (AV) beam with a bent or inclined trajectory shows its great significance in contactless manipulations, especially for objects behind obstacles. By introducing additional phase delays to the traditional single-side ring-array of planar transducers, directional off-axis acoustic-vortex (OA-AV) beams passing through a preassigned point are constructed. Numerical simulations and experimental measurements of the axial and cross-sectional profiles for OA-AV beams of different orders with various radial offsets are conducted for transducers of various radiation patterns. An approximately linear trajectory of OA-AV beams with the slope determined by the preassigned point is demonstrated. The axial distribution of OA-AV beams formed by the main-lobes and side-lobes with corresponding zero-pressure nodes is decided by the directivity of the sources, while the vortex radius can be adjusted by the topological charge. By combining with the technologies of ultrasonic imaging, acoustic treatment, particle assembly, and targeted drug delivery, the precise positioning and flexible regulation of tilted OA-AV beams can be applied to accurately route acoustic packets along a predictable trajectory in three dimensions, suggesting more promising potentials of obstacle-avoidant object manipulation in biomedical applications. [ABSTRACT FROM AUTHOR]

The trapping capability of focused acoustic vortex (FAV) beams along the radial and axial directions has significant potential in biomedical applications. However, analyses based on the acoustic gradient force are only applicable to tiny particles when acoustic scattering is neglected, and the ideal Bessel beams are still difficult to implement in experiments. In the present work, the axial acoustic radiation force (A-ARF) exerted on objects at the focus for FAV beams is calculated based on an annular spherical transducer with a continuous phase spiral. Through a partial wave series expansion, a recursive algorithm based on acoustic scattering is proposed to calculate the acoustic field for FAV beams with arbitrary order. The A-ARF distributions exerted on rigid spheres with respect to k0a (the product of the wave number and the sphere radius) are simulated. The results demonstrate that the A-ARF created by on-axis acoustic reflection is mainly manifested as a pushing force for FAV beams of all orders. The pulling force produced by off-axis scattering is more likely to be exerted on spheres with a smaller k0a in higher-order FAV beams constructed by narrower transducers. The A-ARF generated by a ring-array of sectorial transducers with more than 16 sources can be estimated from the equivalent result produced by the continuous model. The favorable results demonstrate the validity of the recursive algorithm for solving the A-ARF of FAV beams and the feasibility of experimental ring-arrays of spherical sources, suggesting the potential for the application of dual-directional object manipulation in biomedical fields. [ABSTRACT FROM AUTHOR]

Sonoporation mediated by microbubbles is being extensively studied as a promising technology to facilitate gene/drug delivery to cells. However, the theoretical study regarding the mechanisms involved in sonoporation is still in its infancy. Microstreaming generated by pulsating microbubble near the cell membrane is regarded as one of the most important mechanisms in the sonoporation process. Here, based on an encapsulated microbubble dynamic model with considering nonlinear rheological effects of both shell elasticity and viscosity, the microstreaming velocity field and shear stress generated by an oscillating microbubble near the cell membrane are theoretically simulated. Some factors that might affect the behaviors of microstreaming are thoroughly investigated, including the distance between the bubble center and cell membrane (d), shell elasticity (χ), and shell viscosity (κ). The results show that (i) the presence of cell membrane can result in asymmetric microstreaming velocity field, while the constrained effect of the membrane wall decays with increasing the bubble-cell distance; (ii) the bubble resonance frequency increases with the increase in d and χ, and the decrease in κ, although it is more dominated by the variation of shell elasticity; and (iii) the maximal microstreaming shear stress on the cell membrane increases rapidly with reducing the d, χ, and κ. The results suggest that microbubbles with softer and less viscous shell materials might be preferred to achieve more efficient sonoporation outcomes, and it is better to have bubbles located in the immediate vicinity of the cell membrane. [ABSTRACT FROM AUTHOR]

For enhanced energy utilization with improved flexibility and capability for object manipulation, a focused acoustic vortex (FAV) is devised by installing a spherical acoustic lens on a circular array of planar sector transducers. Based on the acoustic refraction of a concave spherical acoustic lens, numerical simulations show that an FAV with considerable pressure gain and strengthened acoustic gradient force (AGF) can be produced by the effective concentration of acoustic waves. The performance of rotational object trapping is shown by the axial and radial distributions of the AGF for FAVs of different orders. Elastic objects of nanometer, micrometer, millimeter, and even larger-than-wavelength size can be captured with the trapping radius determined by the topological charge. With the established 16-channel experimental system, FAVs of different orders are verified by their clear pressure circles and phase spirals. The trapping radius and rotation speed of object capture are demonstrated using polyethylene particles of various sizes and FAVs of different orders. The favorable results provide an experimentally applicable method of FAV generation using the simplified circular transducer array to accomplish more accurate, stable, and flexible object manipulations with strengthened AGFs. Also, FAVs could offer an efficient means of high-intensity focused ultrasound therapy to improve the therapeutic effect of tumor treatments by accumulating drug particles, thereby enabling more potential applications in clinical practice. [ABSTRACT FROM AUTHOR]

As the main way of underwater data transmission, acoustic communication is still limited by the low-level signal-to-noise ratio and channel capacity. The orbital angular momentum (OAM) based acoustic communication of acoustic vortex (AV) provides a new dimension to data transmission with an expanded channel capacity. Theoretical analyses and experimental measurements for the OAM communication of AV beams based on single-ring transceiver arrays are studied in air. Coaxial multi-OAM AV beams are generated with multiple topological charges encoded by the binary ASCII codes of various letters. The OAM modes of the AV beams are decoded with limited acoustic pressures detected by the single-ring receiver array around the vortex center based on the orthogonal property. It is proven that the channel capacity of the communication system can be increased effectively by the OAM modes of AVs, which are beneficial to data encryption and transmission without mutual interference of AVs of different orders. The favorable results provide theoretical bases and technical support to data transmission and OAM decoding for the OAM communication of AV beams using simplified single-ring transceiver arrays. [ABSTRACT FROM AUTHOR]

Based on the analysis of the wave vector of an acoustic-vortex (AV) spanner, the radiation torque of object rotation is investigated. It is demonstrated that the rotation of an axisymmetric disk centered on the AV spanner is mainly driven by the acoustic radiation force. The radiation torque exerted on a small-radius object is inversely associated with the topological charge in the center AV, and it is enhanced significantly for a larger AV with a higher topological charge. With the sixteen-source experimental setup, radius dependencies of radiation torque for AV spanners with different topological charges are verified by quantitative laser-displacement measurements using disks with different radii. The favorable results demonstrate that the radiation torque is more applicable than the orbital angular momentum in describing the driving capability of an AV spanner and can be used as an effective tool in clinical applications to manipulate objects with a feature size at the wavelength-scale inside body. [ABSTRACT FROM AUTHOR]

Weak ties are becoming mainstream in daily relationships and play an essential role in the improvement of individuals' mental health. Despite growing concerns on depression, inclusion of weak ties is limited. To address the gap, this study empirically shed light on the role of weak ties on individual depression in the context of economic development. A cross-sectional study was conducted based on 2018 China Health and Retirement Longitudinal Study (CHARLS) with a sample of 16,545 individuals. A moderated mediation model is constructed to evaluate the impact of economic development (GDP) on the degrees of depression, the mediating effect of weak ties, and the moderating effect of residents' residence types (living in urban or rural areas). Economic development exerts a significant direct impact on depression (β = − 1.027 , p <0.001). Weak ties are significantly negatively correlated with depression (β = − 0.574 , p <0.001), and act as a mediator between economic development and local individual depression. In addition, the residence type plays a moderating role between economic development and weak ties (β = 0.193 , p <0.001). That is, living in urban areas would introduce the higher the level of weak ties. Higher economic development is largely conducive to alleviating the degrees of depression, weak ties play a mediating role between economic development and depression, and residence types exert a positive moderating effect on the economic development and weak ties. • This study empirically shed light on the role of weak ties on individual depression based on 2018 CHARLS. • Economic development could significantly affect degrees of individual depression through the mediating effect of weak ties. • Residence types play a moderating role between economic development and weak ties. [ABSTRACT FROM AUTHOR]

The inevitability of age-related degeneration makes research on degradation mitigation attractive to humans, while exercise is considered an effective means due to its powerful impact on life and health. Caenorhabditis elegans is a model animal with a short life cycle and is widely used in health and aging studies. In this work, ultrasonic stimuli in the form of surface acoustic waves (SAWs) were used to induce behavioral activities in worms. As the worms grew, ultrasound-elicited behavioral responses started to decrease in the early adulthood stage. However, this situation was significantly ameliorated when ultrasonic training sessions at an effective acoustic pressure of 1.1 MPa were performed four times per day for 5 or 7 days, while ultrasonic responses in trained nematodes were stronger than those in untrained ones. These results suggest that long-term ultrasonic training might positively intervene in aging-related degeneration. Besides, it was found that exercise driven by long-term ultrasonic training had insignificant effects on the lifespan of worms. A preliminary exploration of the neural mechanisms underlying the sensation of SAWs was also conducted. The results show that, apart from touch receptor neurons (TRNs), polymodal nociceptors FLP and PVD neurons may also be involved in the perception of ultrasound in C. elegans. The results of this study may inspire related studies on other animals or humans. • An age-related decrease in ultrasound-elicited behavioral responses in C. elegans was observed. • This degeneration of ultrasonic responses could be significantly ameliorated when 5- or 7-day ultrasonic exercise trainings were carried out. • Such long-term training had insignificant effects on the lifespan of worms [ABSTRACT FROM AUTHOR]

Background: As a novel non‐invasive multi‐physics imaging methodology, the magneto‐acousto‐electrical (MAE) technology is capable of detecting electric conductivity changes for biological tissues, exhibiting prosperous perspectives in medical applications. However, the acoustic beam was often simplified to a straight line or a focused one, being perpendicular to layered boundaries of tissues in previous studies. Linear‐scanning measurements were carried out to reconstruct B‐mode MAE images for layered models without considering the radiation pattern of transducers. Obvious image distortions in both shape and brightness were observed in experiments without any reasonable explanation. Purpose: This study aims to establish a general physical model for MAE measurements and solve the problem of B‐mode image distortion, and hence provide theoretical and technical supports for the improvement of MAE imaging in practical applications. Methods: By considering the radiation pattern of actual transducers and the inclined angle of electric conductivity boundaries, a general principal of MAE measurements applicable for objects of arbitrary shapes is proposed based on the theories of acoustic radiation, Hall Effect and electrical detection. The influences of inclined conductivity boundaries and transducer directivities are numerically analyzed with Matlab programming and also demonstrated by experimental measurements. To evaluate the degree of B‐mode image distortion, the deformation length (3 dB amplitude decrease) of approximate straight lines for a circular model is defined as L = dtan(βm/2), with d and βm being the measurement distance and the half radiation angle of the main‐lobe, respectively. The rotary‐scanning‐based MAE tomography (MAET) is employed to reduce the image distortion, and the rotation angle step is further optimized based on the criterion of the boundary radius fluctuation coefficient <0.01 mm. Results: The experimental results of MAE signals and B‐mode images as well as MAETs show good agreements with simulations. It is demonstrated that, as the increase of the inclined angle, the MAE decreases rapidly with an extended time interval and reaches the 20 dB amplitude decrease when the angle exceeds 12°. Meanwhile, the deformation length of B‐mode MAE imaging increases with the increase of the radiation angle for the transducer with a weaker radiation pattern, and hence results in a more serious image distortion. A smaller rotation angle step should be adopted to the MAET system with a longer deformation length, and the optimized maximum angle step of 12° is also achieved for the omnidirectional radiation of point sources with a long deformation length. Conclusion: The image distortion is originated from the amplitude decrease, the time shift and the time interval expansion of MAE signals introduced by the deformation length and the incident angle. The favorable results demonstrate that the fast high‐resolution imaging can be accomplished by the minimum rotations of the rotary‐scanning‐based MAET using an actual transducer, and also provide an optimized scheme for the rotary‐based MAET without scanning using a linear array of point sources. [ABSTRACT FROM AUTHOR]

The high-intensity focused ultrasound (HIFU) has become an attractive therapeutic tool for the noninvasive tumor treatment. The ultrasonic transducer is the key component in HIFU treatment to generate the HIFU energy. The dimension of focal region generated by the transducer is closely relevant to the safety of HIFU treatment. Therefore, it is essential to numerically investigate the focal region of the transducer. Although the conventional acoustic wave equations have been used successfully to describe the acoustic field, there still exist some inherent drawbacks. In this work, we presented an axisymmetric isothermal multi-relaxation-time lattice Boltzmann method (MRT-LBM) model with the Bouzidi-Firdaouss-Lallemand (BFL) boundary condition in cylindrical coordinate system. With this model, some preliminary simulations were firstly conducted to determine a reasonable value of the relaxation parameter. Then, the validity of the model was examined by comparing the results obtained with the LBM results with the Khokhlov-Zabolotskaya-Kuznetsov (KZK) equation and the Spheroidal beam equation (SBE) for the focused transducers with different aperture angles, respectively. In addition, the influences of the aperture angle on the focal region were investigated. The proposed model in this work will provide significant references for the parameter optimization of the focused transducer for applications in the HIFU treatment or other fields, and provide new insights into the conventional acoustic numerical simulations. [ABSTRACT FROM AUTHOR]

Benefiting from their minimally or noninvasive nature, thermal therapies are becoming increasingly important in tumor treatment, in which real-time monitoring of in vivo temperature based on ultrasonic imaging has shown great promise. In this work, an improved dynamic frame selection algorithm and a modified adaptive filtering method were combined with a thermal expansion model, and in vivo temperature monitoring with improved accuracy was achieved. The ultimate aim being the use of thermometry in the thermal treatment of hypertension, experiments targeting the perirenal fat of living pigs were carried out, in which microwaves were applied as a heat source at different power levels. By comparing the echo shift of the ultrasound (US) and the temperature—sensed via a thermocouple—a constant temperature evaluation coefficient was determined. As the tissue was raised to 6.4, 9.8, and 19.3 °C above its base temperature, the root-mean-square evaluation error (ɛrms) was about 0.3, 0.5, and 0.8 °C, respectively. High precision and a high signal-to-noise ratio can help US thermometry play a more important role in monitoring the application of thermal therapies. [ABSTRACT FROM AUTHOR]

Oat bran polysaccharide (OBP), which can lower serum lipid levels and was developed as a safe and effective functional diet to treat cardiovascular diseases, was obtained using ultrasonic-microwave assisted extraction (UME). A maximum OBP extraction efficiency could be achieved when oat bran was processed with 639 W of microwave power, 36:1 of liquid-solid ratio, pH value of 10, and 18 min of UME processing time, according to statistical screening and optimization experiments. When UME was used instead of the standard hot water extraction method, the extraction time was slashed by 6.67 times, the yield of OBP nearly doubled, and OBP activity was unaffected. In vivo rat results showed that the significant anti-hyperlipidaemia activity of OBP was attributed to a decline in triglycerides, total cholesterol, and LDL-C as well as a rise in HDL-C. This is comparable to the positive group outcomes from the use of commercial β-glucan and simvastatin treated group, which may lessen liver fatty lesions and prevent the storage of fat. In conclusion, it is proposed that OBP extraction utilizing UME is a feasible method for anti-hyperlipidemic foods. [Display omitted] • Oat bran polysaccharide (OBP) extraction yield was maximized. • The UME's OBP extraction was 6.67 times faster than the hot water extraction method. • When using UME instead of hot water extraction, the OBP yield was twice as high. • OBP efficiently lowered blood lipid levels, similar to the effects of simvastatin. [ABSTRACT FROM AUTHOR]

• This article presents an innovative approach for real-time monitoring of microwave ablation (MWA) therapy. • By analyzing the acoustic scattering properties of gas generated in ablation areas, this method enables real-time monitoring of the ablation zone. • Validation through ex vivo experiments on porcine liver showed a relative error of about 7% in monitoring the ablation area size. • This technique provide an effective tool and robust support for real-time adjustments and improvements in intraoperative MWA strategies. • The SVD-based real-time monitoring method significantly enhances the precision and safety of ablation therapy. Microwave ablation (MWA) can rapidly lead to tumor cell necrosis by heating local tissues using electromagnetic field energy, making it a highly efficient modality widely utilized in clinical ablation surgeries. However, the lack of timely and accurate intraoperative monitoring methods is a critical issue that urgently needs to be addressed in MWA. This article introduces an innovative approach for real-time monitoring of ablation therapies by the combination of ultrasound radio frequency (RF) signal acquisition and singular value decomposition (SVD), which breaks through the limitations of current monitoring techniques during MWA procedures. Due to the difference in acoustic scattering properties between the gas generated in high-temperature ablated region and the non-ablated tissues, the current new method aimed to apply SVD analyses to ultrasound RF signals scattered from the tissues, through which the range of gas generation could be determined and then the ablation area could be estimated. Eventually, high-precision differentiation between ablated and non-ablated tissues could be achieved, enabling real-time adjustment and improvement of MWA strategies. Validated through ex vivo experiments on pig liver, this technique demonstrated a relative error in monitoring the size of ablation region of approximately 7%, indicating a strong correlation with actual ablation outcomes. The study indicated the proposed method should have great potential to improve the precision and safety of MWA therapy. [ABSTRACT FROM AUTHOR]

Acoustic cavitation plays a critical role in various biomedical applications. However, uncontrolled cavitation can lead to undesired damage to healthy tissues. Therefore, real-time monitoring and quantitative evaluation of cavitation dynamics is essential for understanding underlying mechanisms and optimizing ultrasound treatment efficiency and safety. The current research addressed the limitations of traditionally used cavitation detection methods by developing introduced an adaptive time-division multiplexing passive cavitation imaging (PCI) system integrated into a commercial diagnostic ultrasound platform. This new method combined real-time cavitation monitoring with B-mode imaging, allowing for simultaneous visualization of treatment progress and 2D quantitative evaluation of cavitation dosage within targeted area. An improved delay-and-sum (DAS) algorithm, optimized with a minimum variance (MV) beamformer, is utilized to minimize the side lobe effect and improve the axial resolution typically associated with PCI. In additional to visualize and quantitatively assess the cavitation activities generated under varied acoustic pressures and microbubble concentrations, this system was specifically applied to perform 2D cavitation evaluation for ultrasound thrombolysis mediated by different solutions, e.g. , saline, nanodiamond (ND) and nitrogen-annealed nanodiamond (N-AND). This research aims to bridge the gap between laboratory-based research systems and real-time spatiotemporal cavitation evaluation demands in practical uses. Results indicate that this improved 2D cavitation monitoring and evaluation system could offer a useful tool for comprehensive evaluating cavitation-mediated effects (e.g. , ultrasound thrombolysis), providing valuable insights into in-depth understanding of cavitation mechanisms and optimization of cavitation applications. [ABSTRACT FROM AUTHOR]

• A new MAE model is established based on the coupling of helical wave fronts of Bessel beams in a coaxial toroidal magnet. • The MAE field induced by the Bessel beam of l th order is determined by those of (l -1)th and (l + 1)th orders. • The center-converging rotary MAE field with a constant peak-intensity at the center can only be constructed by the Bessel beam of 1st order. • The MAE field may advance a new synergistic stimulation strategy assisted by center-captured drug particles, with improved accuracy and reduced acoustic energy. The magneto-acousto-electric (MAE) effect shows great significance in neural modulation, whereas the high-precision stimulation cannot be realized by the unidirectional electric distribution perpendicular to the orthogonal acoustic and magnetic fields. A new MAE model is established based on helical wave fronts of Bessel beams in a coaxial magnetic field. Numerical and experimental studies are conducted for quasi-Bessel beams constructed by the saw-tooth phase modulation for a sectorial planar transducer array in a coaxial toroidal magnet. The MAE field induced by the Bessel beam of l th order is determined by those of (l -1)th and (l + 1)th orders. The rotary MAE field with a constant peak-intensity center can only be constructed by the Bessel beam of 1st order, which is effective for neural stimulation. Assisted by therapeutic effects of center-captured drug particles by acoustic-vortex tweezers, the center-converging MAE field may advance a new collaborative stimulation strategy with improved accuracy and reduced acoustic energy. [ABSTRACT FROM AUTHOR]

Understanding the dynamics of coated-microbubble oscillating in an elastic microvessel is important for effective and safe applications of ultrasound contrast agents (UCAs) in imaging and therapy. Numerical simulations are performed based on a two-dimensional (2D) asymmetric finite element model to investigate the influences of both acoustic driving parameters (e.g., pressure and frequency) and material properties (vessel size, microbubble shell visco-elastic parameters and fluid viscosity) on the dynamic interactions in the bubble–blood–vessel system. The results show that, the constrained effect of the blood vessel along the radial direction will induce the asymmetric bubble oscillation and vessel deformation, as well as shifting the bubble resonance frequency toward the higher frequency range. For a bubble (1.5-μm radius) activated by 1-MHz ultrasound pulses in a microvessel with a radius varying between 2 and 6.5 μm, up to 26.95 kPa shear stress could be generated on the vessel wall at a driving pressure of 0.2 MPa, which should be high enough to damage the vascular endothelial cells. The asymmetrical oscillation ratio of the bubble can be aggravated from 0.12% to 79.94% with the increasing acoustic driving pressure and blood viscosity, or the decreasing vessel size and microbubble shell visco-elastic properties. The maximum compression velocity on the bubble shell will be enhanced from 0.19 to 22.79 m/s by the increasing vessel size and acoustic pressure, or the decreasing microbubble shell visco-elasticity and blood viscosity. As the results, the peak values of microstreaming-induced shear stress on the vessel wall increases from 0.003 to 26.95 kPa and the deformation degree of vessel is raised from 1.01 to 1.49, due to the enhanced acoustic amplitude, or the decreasing vessel size, blood viscosity and microbubble shell visco-elasticity. Moreover, it also suggests that, among above impact parameters, microbubble resonance frequency and UCA shell elasticity might play more dominant roles in dynamic interactions of the bubble–blood–vessel system. [ABSTRACT FROM AUTHOR]

Encapsulated microbubbles coupled with magnetic nanoparticles, one kind of hybrid agents that can integrate both ultrasound and magnetic resonance imaging/therapy functions, have attracted increasing interests in both research and clinic communities. However, there is a lack of comprehensive understanding of their dynamic behaviors generated in diagnostic and therapeutic applications. In the present work, a hybrid agent was synthesized by integrating superparamagnetic iron oxide nanoparticles (SPIOs) into albumin-shelled microbubbles (named as SPIO-albumin microbubbles). Then, both the stable and inertial cavitation thresholds of this hybrid agent were measured at varied SPIO concentrations and ultrasound parameters (e.g., frequency, pressure amplitude, and pulse length). The results show that, at a fixed acoustic driving frequency, both the stable and inertial cavitation thresholds of SPIO-albumin microbubble should decrease with the increasing SPIO concentration and acoustic driving pulse length. The inertial cavitation threshold of SPIO-albumin microbubbles also decreases with the raised driving frequency, while the minimum sub- and ultra-harmonic thresholds appear at twice and two thirds resonance frequency, respectively. It is also noticed that both the stable and inertial cavitation thresholds of SonoVue microbubbles are similar to those measured for hybrid microbubbles with a SPIO concentration of 114.7 μg/ml. The current work could provide better understanding on the impact of the integrated SPIOs on the dynamic responses (especially the cavitation activities) of hybrid microbubbles, and suggest the shell composition of hybrid agents should be appropriately designed to improve their clinical diagnostic and therapeutic performances of hybrid microbubble agents. [ABSTRACT FROM AUTHOR]

In treating a circular point-source array using the phase-coded method, a composite acoustic field of multiple off-axis acoustic vortices (AVs) with a centered quasi-plane wave is proposed which is superimposed by an AV beam and a co-axial non-AV beam generated by the even- and odd-numbered source arrays, respectively. The acoustic pressure and the phase of the composite acoustic field are derived using explicit formulae and demonstrated by numerical simulations. Off-axis sub-AVs (SAVs) are shown to be formed at the intersections of the radial pressure distributions of the AV and non-AV beams for the same pressure amplitude and opposite phases. Off-axis SAVs can be generated on a circumference centered with a regular polygon of quasi-plane waves. The radii and azimuthal angles of the off-axis AVs and the radius of the centered quasi-plane wave are determined by the topological charge and the initial phase difference of the acoustic beams. With the established 16-source experimental system, the generation of multiple off-axis SAVs with a centered quasi-plane wave is demonstrated by scanning measurements of the composite field with a topological charge of 1, 2, or 3, which is also proved by the qualitatively consistent simulations for N = 16. The proposed model may be applied to multi-point vortex trapping with homogeneous particle dispersion within a finite area around the central axis. These favorable results provide the feasibility of controllable manipulation for drug particles or cells and suggest wide potential applications in the fields of sonochemistry and biomedical engineering. [ABSTRACT FROM AUTHOR]

Although predicting temperature variation is important for designing treatment plans for thermal therapies, research in this area is yet to investigate the applicability of prevalent thermal conduction models, such as the Pennes equation, the thermal wave model of bio-heat transfer, and the dual phase lag (DPL) model. To address this shortcoming, we heated a tissue phantom and ex vivo bovine liver tissues with focused ultrasound (FU), measured the temperature response, and compared the results with those predicted by these models. The findings show that, for a homogeneous-tissue phantom, the initial temperature increase is accurately predicted by the Pennes equation at the onset of FU irradiation, although the prediction deviates from the measured temperature with increasing FU irradiation time. For heterogeneous liver tissues, the predicted response is closer to the measured temperature for the non-Fourier models, especially the DPL model. Furthermore, the DPL model accurately predicts the temperature response in biological tissues because it increases the phase lag, which characterizes microstructural thermal interactions. These findings should help to establish more precise clinical treatment plans for thermal therapies. [ABSTRACT FROM AUTHOR]

Although the application of high intensity focused ultrasound (HIFU) has been demonstrated to be a non-invasive treatment technology for tumor therapy, the real-time temperature monitoring is still a key issue in the practical application. Based on the temperature-impedance relation, a fixed-point magnetically induced magnetoacoustic measurement technology of treatment efficacy evaluation for tissue thermocoagulation during HIFU therapy is developed with a sensitive indicator of critical temperature monitoring in this study. With the acoustic excitation of a focused transducer in the magnetoacoustic tomography with the magnetic induction system, the distributions of acoustic pressure, temperature, electrical conductivity, and acoustic source strength in the focal region are simulated, and the treatment time dependences of the peak amplitude and the corresponding amplitude derivative under various acoustic powers are also achieved. It is proved that the strength peak of acoustic sources is generated by tissue thermocoagulation with a sharp conductivity variation. The peak amplitude of the transducer collected magnetoacoustic signal increases accordingly along with the increase in the treatment time under a fixed acoustic power. When the temperature in the range with the radial and axial widths of about ± 0.46 mm and ±2.2mm reaches 69 °C, an obvious peak of the amplitude derivative can be achieved and used as a sensitive indicator of the critical status of treatment efficacy. The favorable results prove the feasibility of real-time non-invasive temperature monitoring and treatment efficacy evaluation for HIFU ablation using the magnetically induced magnetoacoustic measurement, and might provide a new strategy for accurate dose control during HIFU therapy. [ABSTRACT FROM AUTHOR]

In order to improve the capability of particle trapping close to the source plane, theoretical and experimental studies on near-field multiple traps of paraxial acoustic vortices (AVs) with a strengthened acoustic gradient force (AGF) generated by a sector transducer array were conducted. By applying the integration of point source radiation, numerical simulations for the acoustic fields generated by the sector transducer array were conducted and compared with those produced by the circular transducer array. It was proved that strengthened AGFs of near-field multiple AVs with higher peak pressures and smaller vortex radii could be produced by the sector transducer array with a small topological charge. The axial distributions of the equivalent potential gradient indicated that the AGFs of paraxial AVs in the near field were much higher than those in the far field, and the distances at the near-field vortex antinodes were also proved to be the ideal trapping positions with relatively higher AGFs. With the established 8-channel AV generation system, theoretical studies were also verified by the experimental measurements of pressure and phase for AVs with various topological charges. The formation of near-field multiple paraxial AVs was verified by the cross-sectional circular pressure distributions with perfect phase spirals around central pressure nulls, and was also proved by the vortex nodes and antinodes along the center axis. The favorable results demonstrated the feasibility of generating near-field multiple traps of paraxial AVs with strengthened AGF using the sector transducer array, and suggested the potential applications of close-range particle trapping in biomedical engineering. [ABSTRACT FROM AUTHOR]

Tea, Camellia sinensis (L) O. Kuntze, is the most popular non‐alcohol beverage and has over a thousand years of cultivation history. Sustainable tea cultivation is hampered by insect and mite pests and heavily relies on conventional pesticides. However, such management strategies can cause environmental pollution and insect resistance. Well‐planted tea ecosystem naturally provides a suitable micro‐climatic condition for the prosperity of natural enemies, especially entomopathogenic fungi (EPF) that are susceptible to moisture, temperature and sunlight. Hence, EPF have been widely used in tea plantations for pest management. Here, we summarized the approaches of research pertaining to EPF diversity in ecosystems. We also describe the general infection process and discuss the environmental factors that impact EPF efficiency. Finally, we listed the successful cases of EPF in tea pest management. Overall, this review has provided the application status and biological potential of EPF, which will contribute to agricultural productivity, and ecological, economic and social sustainability in the tea ecosystem. [ABSTRACT FROM AUTHOR]

Background: Combined with thrombolytic drugs and/or microbubbles, ultrasound (US) has been regarded as a useful tool for thrombolysis treatment by taking its advantages of noninvasive, non‐ionization, low cost, and accurate targeting of tissues deep in body. Recently, low‐intensity pulsed US, which can cause fewer complications by stable cavitation and acoustic streaming other than more violent effects, has attracted broad attention. Purpose: However, the thrombolysis effect in practice might not achieve expectation because there is not an ideal parallel multilayered structure between the skin and the targeted vessel. Therefore, the current work aims to better elucidate the influence of US incident angle on the generation of acoustic streaming and thrombolysis effect. Methods: Systemic numerical and experimental studies, namely, finite element modeling (FEM), particle image velocimetry (PIV), and in vitro thrombolysis measurements, were performed to estimate the acoustical/streaming field pattern, maximum flow velocity, and shear stress on the surface of thrombus, as well as the lysis rate generated at different conditions. These methods aim at verifying the hypothesis that streaming‐induced vortices can further accelerate the dissolution of the thrombus and optimized thrombolysis effected can be achieved by adjusting US incident angles. Results: The pool data results showed that the variation trends of the flow velocity and shear stress obtained from FEM simulation and PIV experiments are qualitatively consistent with each other. There exists an optimal incident angle that can maximize the flow velocity and shear stress on the surface of thrombus, so that superior stirring and mixing effect can be generated. Furthermore, as the flow velocity and shear stress on thrombus surface are both highly correlated with the thrombolysis effect (the correlation coefficient R1 = 0.988, R2 = 0.958, respectively), the peak value of lysis rate (increase by at least 5.02%) also occurred at 10°. Conclusions: The current results demonstrated that, with appropriately determined incident angle, higher thrombolysis rate could be achieved without increasing the driving pressure. It may shed the light on future US thrombolysis planning strategy that, if combined with other advanced technologies (e.g., machine‐learning‐based image analysis and image‐guided adaptive US emission modulation), more efficient thrombolytic effect could be realized while minimizing undesired side‐effects caused by excessively high pressure. [ABSTRACT FROM AUTHOR]

Ultrasonic linear arrays have great potential to generate high-quality three-dimensional (3D) images by scanning the array. However, the generated images suffer from low resolution in the elevation plane, limiting the image quality for a reliable 3D Non-Destructive Testing (NDT) inspection. Although several ultrasonic imaging methods have been implemented to inspect different types of defects, there has been limited research to characterise surface-breaking cracks (SBCs) in 3D quantitatively. To improve the characterisation of surface-breaking cracks (SBCs), a 3D hybrid imaging method is proposed by combining the Half Skip Total Focusing Method (HSTFM) and the Synthetic Aperture Focusing Technique (SAFT) using a linear array. This paper proposed the implementation of an array with a reduced element length for full matrix capture (FMC) data acquisition. In conjunction with the hybrid imaging method, a reduced element array enables the utilisation of the information from a broad ultrasonic beam in the elevation direction to achieve improved image resolution. The imaging capability is assessed via a point spread function (PSF) as well as numerical simulations. From the PSF measurements, the image resolution is shown to improve with the smaller element length of the array, which is attributable to the combination of wide beamwidth and hybrid imaging method. Thereafter, experimental validation was performed with arrays of different elevation lengths, where an excellent match with the numerical results was observed. Furthermore, the crack sizing was performed using a 6-dB-drop rule, which assisted in accurately predicting the shape and size of the SBCs and is shown to measure the depth of SBCs with greater confidence. It is shown that a reduced array elevation with the hybrid imaging method and sizing method yields improved image resolution contrary to conventional linear arrays. This approach can offer a significant improvement in manifesting complete comprehension of the spatial defect relationship, enabling NDT engineers to analyse the inspection results quantitatively in 3D for progressive reliability. • 3D ultrasonic imaging of surface-breaking cracks. • Improved image capability with a hybrid technique combining Half Skip Total Focusing Method (HSTFM) and Synthetic Aperture Focusing Technique (SAFT). • Image resolution improved with reduced array elevation. [ABSTRACT FROM AUTHOR]

• A circular pressure modulation approach for steerable ultrasonic propulsion of rigid objects is developed based on the simplified sector-array of focused transducers. • The general theory of ARF exerting on on-axis rigid spheres is derived in explicit formula for traditional and inclined focused fields based on acoustic scattering. • The ARF acting on on-axis spheres by focused fields exhibits an axial distribution of increasing followed by decreasing with the peak slightly beyond the focus. • Inclined propulsion is realized by adjusting the angle of power-on sources, with the maximum deflection angle determined by the F-number and element number of the sector-array. • This study provides an applicable technique for steerable propulsion of calculi using an ultrasonic power supply without the complex control in amplitude and phase for the sector-array. As a common disease of human urinary system, the high prevalence and incidence rate of renal calculus have brought heavy burden to society. Traditional ultrasonic lithotripsy struggles with the comprehensive elimination of residual fragments and may inadvertently inflict renal damage. Although focused ultrasound can propel stones by the acoustic radiation force (ARF) with minimal tissue damage and enhanced passage rate, it is still lack of the accurate control for calculi at different locations. A circular pressure modulation approach for steerable ultrasonic propulsion of rigid objects is developed based on a sector-array of focused transducers. The ARF exerted on on-axis rigid spheres (stones) is derived based on acoustic scattering. It is proved that the ARF of focused fields exhibits an axial distribution of increasing followed by decreasing with the peak slightly beyond the focus. As the sphere radius increases, the ARF exerted on spheres at the focus increases accordingly with a decreasing growth rate. Inclined propulsion can be realized by the circular binary pressure modulation with the deflection increased by expanding the angle of power-off sector sources. The maximum deflection angle approaching 60° is determined by the F-number and element number of the sector-array. Experimental propulsions of steel balls are conducted using an 8-element sector-array with motion trajectories captured by a high-speed camera. Distributions of the motion speed and acceleration for steel balls of different radii are calculated through image processing. The ARF of mN level and the deflection angle of 12° are demonstrated by the successful propulsion of steel balls. This research provides an effective and flexible approach of steerable stone propulsion using an ultrasonic power supply without the complex control in amplitude or phase and the high-precision motion of the sector-array, hence promoting the practical application in non-invasive treatment of stones. [ABSTRACT FROM AUTHOR]

In traditional Chinese medicine, Ligusticum wallichii (Chuan Xiong) and its bioactive ingredient, tetramethylpyrazine (TMP), have been used to treat cardiovascular diseases and to relieve various neurological symptoms, such as those associated with ischemic injury. In the present study, we investigated whether ultrasound (US) exposure could enhance the protective effect of TMP against cerebral ischemia/reperfusion (I/R) injury. Glutamate-induced toxicity to pheochromocytoma (PC12) cells was used to model I/R injury. TMP was paired with US to examine whether this combination could alleviate glutamate-induced cytotoxicity. The administration of TMP effectively protected cells against glutamate-induced apoptosis, which could be further enhanced by US-mediated sonoporation. The anti-apoptotic effect of TMP was associated with the inhibition of oxidative stress and a change in the levels of apoptosis-related proteins, Bcl-2 and Bax. Furthermore, TMP reduced the expression of proinflammatory cytokines such as TNF-α and IL-8, which likely also contributes to its cytoprotective effects. Taken together, our findings suggest that ultrasound-enhanced TMP treatment might be a promising therapeutic strategy for ischemic stroke. Further study is required to optimize ultrasound treatment parameters. [ABSTRACT FROM AUTHOR]

Abstract: Tissue inhomogeneity might have an important effect on the treatment accuracy of therapeutic ultrasound. Both computer simulation and measurement were performed to study the influence of tissue inhomogeneity on the temperature distribution and tissue lesion formation induced by focused ultrasound. The inhomogeneous tissue is considered a combination of a homogeneous medium and a phase aberration screen in this article. Temperature distributions and lesion dimensions were predicted using the combination of acoustic non-linear and bio-heat transfer equations. To verify the theoretical predictions, polyethylene plates with phase distributions of different correlation lengths and standard deviations were made to mimic inhomogeneous tissues such as human abdominal tissue, and a series of experiments were performed, including acoustic and thermal measurements. The results indicate that the tissue inhomogeneity caused phase aberration of the ultrasound beam. With increasing standard deviation and correlation length of phase aberration, the scattering level of the acoustic field increased, while ultrasound-induced peak temperature and lesion size decreased. This study provides a theoretical and experimental basis for future development of accurate treatment plans for high-intensity focused ultrasound. [Copyright &y& Elsevier]