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For 1–3 piezoelectric composite high-power transducers applied to FUS surgery, avoiding the electro-acoustic output performance fluctuating with the temperature is an important task. In this work, 1–3 type piezocomposites were fabricated with dice and fill method. The PZT4 piezoceramic was used as active phase, and mica powder modified epoxy resin E51 was used as passive phase: the mass ratio of the epoxy and mica powder was 10: x . Those composites were evaluated for power transducer applications with air backing and without front layer. The effect of mica powder modified polymer filler on the electro-acoustic output behavior and thermal stability of the transducer were detailed investigated. The results show that mica power could increase the storage modulus and the toughness of the polymer. As a result, an elevated k t of 0.7 was observed when the adding amount was 50 wt%. The electro-acoustic conversion efficiency ( η ea ) of the transducer substantial increased to 81–83% and with good thermal stability when x  = 1–5. The research results show that adding mica powder in the filler materials was one of the potential methods to prepare high-power piezocomposite transducer.

The emergence of high-intensity focused ultrasound applications brings great potential to establish noninvasive therapeutic treatment in place of conventional surgery. However, the development of ultrasonic technology also poses challenges to the design and manufacture of high-power ultrasound transducers with sufficient acoustic pressure. Here, the design of a sector vortex Archimedean spiral phased array transducer that is able to enhance focal acoustic pressure is proposed by maximizing the filling factor of the piezoelectric array. The transducer design was experimentally verified by hydrophone measurements and matched well with acoustic simulation studies. The focal deflection was shown to be feasible up to ±9 mm laterally and up to ±20 mm axially, where the effective focal acoustic pressure can be maintained above 50% and the level of the grating lobe below 30%. Furthermore, a homogeneous pressure distribution without secondary focus was observed in the pre-focal region of the transducer. The rational design of a high-intensity focused ultrasound transducer indicates promising development in the treatment of deep tissue thermal ablation for clinical applications.

Porcine epidemic diarrhea virus (PEDV) has emerged in American countries, and it has reemerged in Asia and Europe, causing significant economic losses to the pig industry worldwide. In the present study, the 17GXCZ-1ORF3d strain, which has a naturally large deletion at the 172–554 bp position of the ORF3 gene, together with the 17GXCZ-1ORF3c strain, was serially propagated in Vero cells for up to 120 passages. The adaptability of the two strains gradually increased through serial passages in vitro. Genetic variation analysis of the variants of the two strains from different generations revealed that the naturally truncated ORF3 gene in the 17GXCZ-1ORF3d variants was stably inherited. Furthermore, the survival, viral shedding and histopathological lesions following inoculation of piglets demonstrated that the virulence of 17GXCZ-1ORF3d-P120 was significantly attenuated. These results indicate that the naturally truncated ORF3 gene may accelerate the attenuation of virulence and is involved in PEDV virulence together with mutations in other structural genes. Importantly, immunization of sows with G2b 17GXCZ-1ORF3d-P120 increased PEDV-specific IgG and IgA antibody levels in piglets and conferred partial passive protection against heterologous G2a PEDV strains. Our findings suggest that an attenuated strain with a truncated ORF3 gene may be a promising candidate for protection against PEDV.

Based on the acousto-optic interaction, we propose a laser deflection method for rapidly, non-invasively and quantitatively measuring the peak positive pressure of HIFU fields. In the characterization of HIFU fields, the effect of nonlinear propagation is considered. The relation between the laser deflection length and the peak positive pressure is derived. Then the laser deflection method is assessed by comparing it with the hydrophone method. The experimental results show that the peak positive pressure measured by laser deflection method is little higher than that obtained by the hydrophone, confirming that they are in reasonable agreement. Considering that the peak pressure measured by hydrophones is always underestimated, the laser deflection method is assumed to be more accurate than the hydrophone method due to the absence of the errors in hydrophone spatial-averaging measurement and the influence of waveform distortion on hydrophone corrections. Moreover, noting that the Lorentz formula still remains applicable to high-pressure environments, the laser deflection method exhibits a great potential for measuring HIFU field under high-pressure amplitude. Additionally, the laser deflection method provides a rapid way for measuring the peak positive pressure, without the scan time, which is required by the hydrophones.

Background Acoustic cavitation plays an important role in the medical treatment using high-intensity focused ultrasound (HIFU), but unnecessarily strong cavitation also could deform the morphology and enlarge the size of lesions. It is known that the increase of ambient hydrostatic pressure ( P stat ) can control the acoustic cavitation. But the question of how the decrease of P stat and dissolved oxygen concentration (DOC) influence the strength of cavitation has not been thoroughly answered. In this study, we aimed to investigate the relationship among the P stat , DOC and the strength of cavitation. Methods Ex vivo bovine liver tissues were immersed in degassed water with different DOC of 1.0 mg/L, 1.5 mg/L and 2.0 mg/L. Ultrasound (US) of 1 MHz and the spatial and temporal average intensity ( I sata ) of 6500 W/cm 2 was used to expose two groups of in vitro bovine livers for 2 s; one group was under atmospheric pressure ( P stat  = 1 bar) and the other was under sub-atmospheric pressure ( P stat  = 0.1 bar). Acoustic cavitation was detected by a passive cavitation detector (PCD) during the exposure process. Echo signals at the focal zone of HIFU were monitored by B-mode ultrasound imaging before and after exposure. The difference between two pressure groups was tested using paired sample t -test. The difference among different DOC groups was evaluated by one-way analysis of variance (ANOVA). Results The results demonstrated a significant difference of broadband acoustic emissions from the cavitation bubbles, echo signals on B-mode image, morphology of lesions under various conditions of ambient pressure and DOC. The lesion volume in tissue was increased with the increase of ambient pressure and DOC. Conclusion Cavitation could be suppressed through sub-atmospheric pressure and low DOC level in liver tissue, which could provide a method of controlling cavitation in HIFU treatment to avoid unpredictable lesions.

To build up a combined therapy strategy to address limitations of the enhanced permeability and retention (EPR) effect and improve the efficiency of tumor therapy. : A pH-sensitive nanocomplex for co-delivery of doxorubicin (DOX) and all-trans retinoic acid (ATRA) was developed based on nanodiamonds (DOX/ATRA-NDs) to enhance intracellular retention of drugs. Meanwhile, ultrasound was employed to enhance tumor vascular penetration of DOX-ATRA-NDs. The distribution of DOX/ATRA-NDs in the tumor tissues increased threefold when ultrasound was applied at 1 MHz and 0.6 W/cm . Comparing with unmodified chemotherapeutics, the combined therapy induced more tumor cells apoptosis and greater tumor growth inhibition in both liver and breast tumor models. DOX-ATRA-NDs demonstrate great potential in clinical applications.

Circular RNAs (circRNAs) are covalently closed, stable non‐coding RNAs that regulate diverse cellular processes. Here, we identify circTspan3 — derived from exons 2–6 of the Tspan3 gene — as a key regulator of cartilage development. The expression of circTspan3 is significantly downregulated in X‐box binding protein 1 ( Xbp1 ) conditional knockout (cKO) mice displaying chondrodysplasia and positively correlates with anabolic markers of cartilage. The XBP1 spliced (XBP1s) transcriptionally upregulates circTspan3 , which in turn promotes anabolic activity in chondrocytes while suppressing both apoptosis and ferroptosis. Mechanistically, phosphorylation of ANNEXIN A2 (ANXA2) at Ser26 facilitates the cytoplasmic translocation of circTspan3 , where ANXA2 mediates its packaging into exosomes for paracrine signalling. Exosomal circTspan3 enhances growth‐plate expansion and effectively repairs cartilage defects in vivo. These findings highlight circTspan3 as a key modulator of growth‐plate homeostasis and suggest its translational potential in treating cartilage injury and growth‐associated skeletal disorders.

Harmonic rejection ability and reflection coefficient are the most important factors in the design of impedance matching network. However, stability of impedance matching should be taken into account in applications existing load impedance variation and component deviation due to tolerance and process variation. This paper investigates variability of Pi network impedance matching analytically. The relationships between resulting reflection coefficient with component deviation and load impedance variation are theoretically derived on the basis of Q-based design method. The deviation from perfect match due to component deviation is proportional to quality factor. Higher quality factor probably means poorer quality in terms of variability. The resulting reflection coefficient caused by load impedance variation increases rapidly when the load reflection coefficient is larger than 0.66. A small variation in the load impedance will cause a large deviation from perfect match when the impedance difference between load and source is quite large.

Background Social frailty has not been comprehensively studied in China. Our objective is to investigate the prevalence of social frailty among the older population in China, as well as identify relevant factors and urban-rural differences. Methods We obtained data from the Fourth Sample Survey of the Aged Population in Urban and Rural China (SSAPUR) database. The study employed a multistage, stratified, cluster-sampling method, recruiting a total of 224,142 adults aged 60 years or older. Participants were interviewed to gather demographic data and information on family, health and medical conditions, health care service status, living environment conditions, social participation, protected rights status, spiritual and cultural life, and health. Social frailty was assessed using the HALFE Social Frailty Index. A score of three or above indicated social frailty. Results We analyzed a total of 222,179 cases, and the overall prevalence of social frailty was found to be 15.2%. The highest prevalence was observed among participants aged 75–79 years (18.0%). The prevalence of social frailty was higher in rural older populations compared to urban older populations (19.9% in rural vs. 10.9% in urban, P < 0.0001). In urban areas, women had a higher prevalence than men (11.7% in women vs. 9.9% in men, P < 0.0001), while in rural areas, men had a higher prevalence than women (20.6% in men vs. 19.2% in women, P < 0.0001). Multivariate regression analysis revealed that living in a rural/urban environment (OR 1.789, 95% CI 1.742–1.837), absence of a spouse/spousal presence (OR 4.874, 95% CI 4.743–5.009), self-assessed unhealthy/health status (OR 1.696, 95% CI 1.633–1.761), and housing dissatisfaction/satisfaction (OR 2.303, 95% CI 2.233–2.376) were all significantly associated with social frailty. Conclusions Using the HALFE social frailty index, we found a prevalence of 15.2% among older people in China, with the highest prevalence observed in the 75–79 age group. Social frailty was more prevalent in rural areas than in urban areas. Various factors, including spousal presence, housing satisfaction, health status, and urban-rural residential differences, were significantly associated with social frailty. These findings highlight the modifiable and non-modifiable factors that contribute to social frailty among older individuals in China.

Current research lacks an in-depth exploration of ensemble learning and factor engineering applications in regard to landslide susceptibility modeling. In the Three Gorges Reservoir area of China, a region prone to frequent landslides that endanger lives and infrastructure, this study advances landslide susceptibility prediction by integrating ensemble learning with systematic factor engineering. Four homogeneous ensemble models (random forest, XGBoost, LightGBM, and CatBoost) and two heterogeneous ensembles (bagging and stacking) were implemented to evaluate 14 influencing factors. The key results demonstrate the Digital Elevation Model (DEM) as the dominant factor, while the stacking ensemble achieved superior performance (AUC = 0.876), outperforming single models by 4.4%. Iterative factor elimination and hyperparameter tuning increased the high-susceptibility zones in the stacking predictions to 42.54% and enhanced XGBoost’s low-susceptibility classification accuracy from 12.96% to 13.57%. The optimized models were used to generate a high-resolution landslide susceptibility map, identifying 23.8% of the northern and central regions as high-susceptibility areas, compared to only 9.3% as eastern and southern low-susceptibility zones. This methodology improved the prediction accuracy by 12–18% in comparison to a single model, providing actionable insights for landslide risk mitigation.