Search Results (587)

Histotripsy is an emerging nonthermal, nonionizing, and noninvasive focused ultrasound therapy that uses acoustic cavitation to mechanically disrupt targeted tissue. In the liver, histotripsy may offer several advantages over conventional locoregional therapies, including treatment without percutaneous probes, treatment of select tumors near vascular or biliary structures, and potential proposed preclinical immunomodulatory effects. Early clinical studies, such as the THERESA and #HOPE4LIVER trials, have demonstrated high technical success rates and relatively low rates of major complications; however, expanding real-world evidence has identified clinically important complications including vascular injury, portal vein thrombosis, and acute kidney injury. Additional prospective studies are needed to determine long-term local tumor control, survival benefits, optimal patient selection, and the role of histotripsy in combination with systemic therapies and other locoregional treatments. This narrative review summarizes the possible mechanism of action, clinical outcomes, safety profile, patient selection considerations, and future directions of histotripsy for the treatment of primary and metastatic liver tumors. Full article

Orange waste (OW) is an example of biomass that has a potential for nutrients and energy recovery. However, its use in biological processes, e.g., anaerobic digestion (AD), still poses a significant technological challenge due to the presence of hardly biodegradable lignin and compounds toxic to the microorganisms. To release its energetic potential, the use of an adequate pre-treatment method might be a solution. This research evaluated the efficacy of various pre-treatment strategies, i.e., acoustics (AC) and hydrodynamic cavitation (HC), microwave radiation (MR), and the impact of solidified carbon dioxide (SCD) in improving the properties of OW, including organic compound content, fiber components, morphological structure, and generation of toxic intermediates. The obtained results showed that HC might be considered as the most efficient pre-treatment strategy prior to its further AD decomposition. For this strategy, an over 2-fold increase in biodegradability index, expressed as the DOC/TOC (dissolved to total organic carbon) ratio, was found. In turn, the other analyzed parameters, i.e., removal of organic compounds and delignification degree, were established at the favorable level of 63 and 56%, respectively. This effect was achieved with the lowest energy demand of 0.35 MJ/kgVS. However, HC favored the generation of AD inhibitors. However, to fully assess the impact of selected methods on AD performance, further experiments should be conducted. Full article

Owing to their exceptional thermal insulation and protective capabilities, thermal barrier coatings (TBCs) are widely applied to critical hot-section components of aero-engines. However, under increasingly harsh service environments, internal defects such as delamination tend to form within the coatings, posing a severe threat to engine operational safety and service life. To effectively evaluate delamination defects in TBCs, this study employs the immersion ultrasonic pulse-echo technique to inspect specimens subjected to various thermal cycling treatments. Four specimens, subjected respectively to 21, 32, 43, and 54 thermal cycles at 1200 °C, were tested. Ultrasonic response data were systematically acquired via normal incidence scanning from both the superalloy substrate side and the ceramic top coat side. Combining Fast Fourier Transform (FFT), Continuous Wavelet Transform (CWT) based on the generalized Morse wavelet, Wavelet Packet Energy Entropy (WPEE), and peak-to-peak amplitude variations of the second echo, multi-dimensional features were extracted from ultrasonic signals across the frequency domain, joint time-frequency domain, and energy distribution profiles. Through comparative analysis, ultrasonic waveform and time-frequency characteristics representing defect evolution were obtained. A significant monotonically decreasing trend of WPEE with the aggravation of interfacial delamination was established, characterizing the acoustic energy confinement process induced by interfacial damage. Furthermore, a multilayer finite element (FE) model reasonably reproduced dynamic acoustic wave propagation; numerical results are in agreement with experimental data, validating the feasibility of the proposed detection method. The detection and evaluation framework established in this study provides a reference for safety monitoring and lifespan prediction of aero-engine TBCs. Full article

This study presents a configurable speech signal preprocessing and feature-extraction workflow for identifying candidate acoustic biomarkers in acute heart failure. The workflow was evaluated in 12 patients hospitalized with acute heart failure. Short recordings of repeated vowels /a/, /i/, and /o/ were acquired shortly after admission and again before discharge following treatment and clinical stabilization. The pipeline included active-RMS normalization, automatic segmentation of repeated vowels, optional edge trimming, alternative pitch-estimation variants, and extraction of three feature families: phonatory and temporal measures, spectral-shape descriptors, and MFCC-based cepstral features. Within-patient admission-to-discharge differences were evaluated using two-sided Wilcoxon signed-rank tests, with nominal p-values interpreted as exploratory. Phonatory and temporal measures produced the most consistent exploratory findings. The pause-duration trend for /a/ decreased between admission and discharge and was the most configuration-stable individual candidate. CPP maximum and CPP range for /o/ increased consistently across the evaluated phonatory configurations, indicating systematic changes in cepstral prominence. Shimmer-related measures provided additional exploratory findings. MFCC measures showed complementary changes, particularly in MFCC11 variability for /o/, whereas spectral-shape effects were generally weaker and less consistent. Because the study involved a small, single-center cohort without a control group or external validation, the findings should be regarded as hypothesis-generating candidate acoustic measures rather than clinically validated biomarkers. Full article

Background/Objectives: The aim of this study was to apply data-driven clustering techniques for the subtyping of tinnitus severity to a retrospective cross-sectional cohort of 564 subjects. Additionally, the response of the resulting phenotypes to an enriched acoustic environment (EAE) treatment was investigated. Methods: A hierarchical decision cascade was applied to classify the measured audiograms of participants into six hearing loss (HL) patterns. K-clustering techniques were applied to demographic (gender), hearing (average audiometric threshold, HL pattern), tinnitus (tinnitus onset age, duration, severity, lateralisation, type of sound, aetiology) and emotional variables. Subjects received customised EAE stimulus to be listened to for one hour daily over four months. Results: Five phenotypes were found by applying K-clustering techniques to numerical and categorical variables. EAE provided an average tinnitus severity reduction of 24.3 points, which was clinically relevant and statistically significant, in 78% of subjects who completed the four-month treatment. Conclusions: Analysis of the performance of EAE treatment in the different phenotypes afforded clear differences in the composition of excluded, dropped out, and not improved subjects. Absolute mean improvement of both severity and emotional scores was larger in phenotypes PH3 and PH4, as they had higher tinnitus distress and emotional symptoms at baseline. Nevertheless, relative change of severity score was notably smaller in PH4. Full article

Background/Objectives: The blood–brain barrier (BBB) remains a major obstacle to effective gene therapy for neurological disorders by limiting delivery of viral vectors, nanoparticles, and biologics to the central nervous system. Multiple strategies have been developed to transiently disrupt or bypass the BBB, including focused ultrasound (FUS) with microbubbles, osmotic agents, biochemical modulators, and receptor-mediated transport systems. Among these approaches, FUS-mediated BBB opening has emerged as the most spatially precise and clinically advanced strategy. Methods: This narrative review synthesizes recent preclinical and clinical literature on BBB microdisruption technologies for central nervous system gene therapy, with primary emphasis on FUS combined with microbubbles. We review BBB physiology, gene delivery platforms, the development of FUS technologies, optimization parameters, and translational evidence across neurological diseases from animal models through early-phase human studies. Results: FUS-mediated BBB opening has emerged as the leading method for transient barrier modulation. Preclinical studies in Parkinson’s disease, Alzheimer’s disease, Huntington’s disease, glioblastoma, amyotrophic lateral sclerosis, and lysosomal storage disorders demonstrate enhanced gene delivery, increased transgene expression, and improved functional outcomes. Large-animal studies and early clinical trials indicate that BBB opening is reversible, spatially controlled, and generally well tolerated. Clinical investigations have demonstrated successful delivery of therapeutic agents across neurological indications, with preliminary efficacy signals including improved drug penetration, metabolic changes, and potential survival benefits. Optimization of acoustic parameters, microbubble characteristics, and real-time cavitation monitoring remains critical for maximizing safety and therapeutic efficacy. Conclusions: BBB microdisruption, particularly through FUS with microbubbles, represents a transformative platform for central nervous system gene therapy. Continued research is needed to standardize treatment protocols, characterize long-term safety, and facilitate broader clinical translation. Full article

Mineral-scale deposition remains a persistent flow-assurance and asset-integrity constraint in oil and gas production. Calcium carbonate, calcium sulfate, barium sulfate, iron sulfide, and mixed inorganic scale deposits reduce tubing internal diameter. They also impair near-wellbore permeability, block safety-critical valves, reduce heat-transfer efficiency, and intensify under-deposit corrosion. Conventional management relies on prediction, chemical inhibition, squeeze treatments, acid dissolution, chelation, mechanical scraping, milling, jetting, and operational water management. These methods are indispensable, but each has a restricted operating envelope. Key limitations include mineral selectivity, corrosion risk, environmental discharge, intervention cost, debris generation, and poor effectiveness against chemically resistant sulfate scales, particularly BaSO₄. Ultrasound has therefore attracted interest as a non-chemical technology. Acoustic cavitation, microstreaming, pressure oscillation, mechanical vibration, and micro jetting may suppress nucleation, disturb boundary layers, weaken adhesion, and fragment brittle deposits. This review critically evaluates ultrasound-assisted scale prevention and removal, with emphasis on production tubing and oilfield relevance. Existing studies show credible mechanistic plausibility and promising laboratory performance for CaCO₃, CaSO₄/gypsum, KCl, NaCl, and membrane or heat-transfer fouling systems. It also compares performance metrics, field cases, and technology-readiness barriers. The evidence is less mature for long steel tubulars operating under high-pressure, high-temperature, multiphase production conditions. Current evidence positions ultrasound at technology-readiness level (TRL) 3–4 for CaCO₃ and CaSO₄ systems, where laboratory and bench-scale validation is established, and at TRL 2–3 for BaSO₄, where mechanistic plausibility exists but controlled experimental validation remains absent. The technology is not yet at the pilot–production transition for downhole tubing applications, but it is approaching that threshold for surface process equipment. Its most credible near-term role is as an intensifier paired with low-dose chemical inhibitors, where acoustic boundary-layer disruption can reduce the minimum inhibitory concentration threshold of inhibitors, and with mild chelating agents for early-stage BaSO₄ management, where ultrasound-enhanced mass transfer may accelerate chelant penetration into deposit microstructure. Advancing ultrasound from its current TRL toward field qualification requires targeted BaSO₄ scale validation in steel tubing systems, acoustic field mapping under HPHT multiphase conditions, mass-removal metrics, and a structured pilot programme. Full article

Hybrid structural materials (HSMs), such as nanoparticle-treated fabrics, have been shown to enhance acoustic and ballistic performance in multifunctional protective structures. They offer a promising means for low-frequency (<~1000 Hz) noise mitigation, which remains a critical challenge in aerospace and defense applications. The measurement and modeling of their sound transmission loss (TL) behavior using a coupled acoustic–poroelastic approach is explored in this study. A colloid-based soaking and drying process is used to impregnate nanoparticles into the fabric. Previous studies using SEM imaging have established that at low (<~20 wt.%) treatment levels, the nanoparticles agglomerate in the interstitial spaces between yarn crossover points, whereas at higher levels, they begin to coat the yarn bundle tops. TL was measured experimentally using normal-incidence impedance tube tests. Further, parameters such as static flow resistivity, porosity, flexural modulus, and density required to model the neat and treat samples as fluid-filled porous solids using the Biot–Allard model were obtained from experiments for a limited set of neat and treated cases. Static flow resistivity was measured using an air permeability tester as per ISO 9237, and a modified version of the Peirce’s cantilever beam test was used to obtain the flexural modulus for neat and treated samples. Porosity was estimated using digital image analytics. The poroelastic fabric model was implemented in finite element simulations, and the predicted TL was compared with experiments including those for uncalibrated treated cases. The model shows close alignment with measured TL at low frequencies (<~600 Hz) for all cases but deviates closer towards the theoretical mass law at higher frequencies, where flanking effects and the influence of the hierarchy of pores are expected to be dominant in experiments. Further studies are underway to incorporate such higher-order effects to improve predictions at higher frequencies. The development of this model provides a means to capture the influence of nanoparticle addition on the acoustic performance of Kevlar, enabling fast and efficient virtual design iterations. The approach helps optimize HSMs for noise mitigation in multifunctional applications for the aerospace, defense, and infrastructural sectors. Full article

High-precision, long-endurance navigation remains a central bottleneck for autonomous underwater vehicles (AUVs) operating in GNSS-denied, acoustically constrained, and dynamically disturbed marine environments. This manuscript examines the complete sensing-mapping-estimation chain for underwater geomagnetic navigation. It distinguishes scalar and vector measurements; compares shipborne, towed, and AUV-mounted survey configurations, calibration requirements, platform-interference mitigation, and uncertainty sources; reviews global, regional, and local magnetic models; and evaluates nonlinear map-aided positioning. Existing approaches are organized into map-based matching, filter-aided navigation, geomagnetic simultaneous localization and mapping (SLAM), and matching-area adaptability assessment. Their assumptions, data requirements, uncertainty treatment, accuracy evidence, and computational burden are critically compared. Persistent gaps include magnetic cleanliness, three-dimensional mapping, weak-feature-area observability, benchmark datasets, uncertainty quantification, and reproducible long-duration sea trials. Full article

The transition from internal combustion engine vehicles to battery electric vehicles has changed the acoustic design problem in automotive engineering. The absence of combustion-related masking increases the perceptibility of tonal and narrowband sources, including gear whine, electric motor orders, inverter-related components, tire cavity resonances, auxiliary system noise, and lightweight-panel radiation. At the same time, mass-based acoustic treatments conflict with electric vehicle lightweighting, range, cost, and sustainability targets. Vibroacoustic metamaterials offer an alternative route by manipulating elastic and acoustic wave propagation through architected geometries, local resonances, periodicity, membranes, lattice architectures, and adaptive or topological wave-control mechanisms. This review examines vibroacoustic metamaterials for low-frequency electric vehicle noise, vibration, and harshness (EV NVH) from an engineering perspective. It covers mechanisms, EV-specific NVH problems, component applications, materials, manufacturing, modeling, validation, AI-assisted design, sustainability, and technology readiness. Particular emphasis is placed on order-targeted, path-oriented, manufacturable, and experimentally validated solutions for electric-drive (e-drive) housings, wheel arches, battery enclosures, body panels, covers, and auxiliary systems. The review concludes that vibroacoustic metamaterials are most promising when integrated into conventional NVH workflows through order analysis, transfer path ranking, robust resonator tuning, durability validation, and multi-objective design optimization. Full article

Microbially Induced Carbonate Precipitation (MICP) and Enzyme-Induced Carbonate Precipitation (EICP) have emerged as promising sustainable alternatives to conventional ground improvement techniques. This paper presents a focused review of Cone Penetration Test (CPT)-based assessment of bio-cemented soils, synthesizing findings from studies spanning laboratory column tests, centrifuge models, and field trials. The review examines how CPT measurements, including tip resistance (q_c), sleeve friction (f_s), and pore pressure response (u), reflect the cementation mechanisms, treatment heterogeneity, soil-type effects, and scale dependency characteristic of MICP and EICP treatments. Key findings indicate that MICP and EICP produce distinct CPT responses: MICP-treated sands generally show stronger cementation-related stiffness signatures and more persistent improvement, whereas EICP-treated soils more commonly exhibit sharper near-surface q_c gains that may be more susceptible to reduction with time. However, long-term field CPT evidence for EICP durability remains limited. CPT interpretation is more uncertain in fine-grained and heterogeneous soils, where low permeability, preferential flow, localized cementation, and penetration-induced disturbance can produce irregular profiles that are difficult to interpret from q_c alone. Fundamental limitations of conventional q_c-based CPT interpretation in bio-cemented ground are identified, including its inability to decouple cementation effects from density, stress state, and environmental variability. Multi-sensor CPT platforms integrating shear-wave velocity probes, acoustic emission monitoring, and geochemical sensors are identified as the most promising pathway toward reliable characterization. Three priority developments are outlined: standardized CPT interpretation protocols with calibrated conversion functions for major soil types, validated multi-sensor platforms deployable under field conditions, and machine-learning tools for spatial treatment quality assessment. This review provides a structured CPT-based synthesis of bio-cemented ground and establishes an interpretive basis for future standardized assessment protocols in geotechnical practice. Full article

Focused ultrasound (FUS) comprises a diverse group of non-invasive, non-ionizing acoustic technologies that have evolved from tools for localized tissue destruction into platforms capable of influencing complex biological processes. In oncology, growing evidence suggests that the effects of focused ultrasound extend beyond direct tumor treatment to include modulation of the tumor microenvironment and anti-tumor immunity. This review examines the major FUS modalities currently under investigation for cancer therapy, including high-intensity focused ultrasound (HIFU), intrinsic threshold histotripsy, boiling histotripsy, shock-scattering histotripsy, and low-intensity focused ultrasound (LIFU), with emphasis on the distinct physical mechanisms that underlie their biological effects. Although these modalities differ in how they interact with tissue, they share the capacity to alter tumor biology through changes in antigen availability, inflammatory signaling, and immune cell activity. These responses have been associated with enhanced immune recognition of tumors, remodeling of immunosuppressive microenvironments, and improved therapeutic responsiveness in preclinical and emerging clinical studies. As interest in focused ultrasound continues to expand, understanding the relationship between modality-specific bioeffects and downstream immune outcomes has become increasingly important. Collectively, the literature highlights focused ultrasound as a versatile therapeutic platform capable of linking precise local intervention with broader biological and immunological consequences, supporting its continued development as both a tumor-directed and immune-modulating strategy in cancer therapy. Full article

Large sensor arrays are an increasingly popular sampling method among ecologists. To last in the field, sensor housing needs to be resistant to damage from both weather and animals. The popular AudioMoth acoustic recorder does not have integral weather-resistant housing and is deployed by users in a wide variety of protective cases. One inexpensive way to protect AudioMoths is to deploy them in plastic bags, which offer moderate weather resistance but are susceptible to chewing damage from small mammals. In this study, we test the effectiveness of commercially available mammal deterrents in preventing such chewing damage. We deployed 115 treatment-control pairs across two grids in temperate forests in Pennsylvania. Bag treatments consisted of Liquid Fence, Bonide, and a cayenne and Vaseline mixture. For all deterrents, there was no statistically significant difference in the proportion or severity of mammal chewing damage between treatments and controls. Counter to expectations, for all three treatments, more of the bags treated with a deterrent were damaged by mammal chewing than the paired control bags. Our results strongly suggest that single applications of these three deterrents have no useful effect on preventing mammal chewing damage to sensor housing in the field. Full article

Respiratory sound monitoring is a promising non-invasive tool for precision pig farming, but practical evidence from calibrated room-level deployment under degraded air-quality conditions remains limited. This study reports a 28-day exploratory room-level case study in which 52 growing pigs were housed in two rooms: one standard-ventilation room and one ventilation-restricted room, and monitored with one microphone per room emphasizing mixed room-level soundscape monitoring rather than individual pig cough counts or replicated treatment inference. Because the design lacked independent room-level replication, all room contrasts and p-values were interpreted as exploratory descriptive screening summaries rather than causal treatment effects. Airflow verification, playback calibration at multiple pen positions, and background-noise spectral analysis were performed to address measurement bias. Signal inspection showed that biologically relevant vocal energy was retained after 16 kHz resampling, while class imbalance was handled by inverse-frequency weighting and macro-F1-based model selection. The Audio Spectrogram Transformer (AST) pipeline was subjected to five-fold group-blocked cross-validation, and temporal validation. The model achieved a test macro-F1 of 0.937, five-fold macro-F1 of 0.928 ± 0.019, and three-day deployment validation macro-F1 of 0.914. In this two-room dataset, the ventilation-restricted room displayed higher room-level cough-like detections, aggressive vocalizations, normal vocalizations, lower silence, reduced growth, and poorer air quality. Cough-like detections showed recurring clock-time clustering, with the most sustained elevation during 19:00–22:00 and a smaller peak around 10:00 with the highest occurrences at 20.00 (2.84 room-level cough-like detections standardized to group size). Audio-only early-warning analysis flagged deteriorated air-quality windows with AUROC = 0.91 and AUPRC = 0.88 and provided a median 34 min lead time before environmental threshold exceedance, highlighting practical utility as an early inspection cue for farmers before air-quality deterioration becomes more pronounced. Cough-like events descriptively co-varied positively with NH₃, temperature, and CO₂. Overall, calibrated AST-based monitoring can summarize group-level acoustic changes associated with degraded room environments, while multi-room and multi-farm replication remains necessary for causal inference and generalization. Full article

Background: Coronary artery bypass grafting (CABG) is the standard revascularization procedure, and the left internal mammary artery (LIMA) is the most widely used conduit owing to its long-term patency and favorable impact on survival. Although fibrosis and calcification are comparatively infrequent in internal mammary artery (IMA) grafts, progressive remodeling may still compromise patency. Tumor necrosis factor-α (TNF-α) is a pro-inflammatory cytokine implicated in vascular remodeling and calcification, whereas L-arginine, a precursor of nitric oxide, may exert vasoprotective effects. Aim: To investigate the effects of ex vivo TNF-α and combined TNF-α plus L-arginine treatment on the morphology, calcification, elemental composition, and biomechanical properties of human LIMA grafts. Patients and Methods: LIMA graft segments from 18 male CABG patients were allocated to one control group (G0) and two ex vivo treatment groups. Grafts were assessed using hematoxylin and eosin and Masson’s Trichrome staining under brightfield microscopy, using Alizarin Red S fluorescence staining to measure calcification, and by scanning electron microscopy with energy-dispersive spectroscopy (SEM/EDS) to assess ultrastructure and elemental composition. Scanning acoustic microscopy (SAM) was used to derive acoustic impedance as a label-free index of tissue stiffness. Results: TNF-α treatment was associated with increased acoustic impedance, consistent with graft stiffening, together with greater calcification signatures, whereas combined TNF-α and L-arginine treatment shifted impedance toward control-like values and showed more organized tissue architectures with reduced calcification. Conclusions: In this preliminary ex vivo model, L-arginine attenuated TNF-α-associated remodeling and stiffening of LIMA grafts, suggesting a potential role in supporting graft durability; larger, statistically powered studies with molecular validation are required to confirm these findings. Full article