Acoustic manipulation for metal additive manufacturing powder sorting.

Assessment of the uncertainty of shear wave speed measurements in ultrasound elastography.

Acoustical particle conveyors via Bessel-beam superposition.

Optical radiation forces on Rayleigh spheres produced by focused vortex higher-order cosine-hyperbolic-Gaussian beams

Chemotherapy has been clinically used for cancer treatment. However, insufficient drug concentration at the target site limits the therapeutic effect. Here, we introduce an in vivo target drug enrichment method, which is based on spatiotemporal acoustic node modulation (STANM). In such a time-varying acoustic field, there are spatially-shifting acoustic radiation forces on the drug-loaded microparticles that move them toward the focus. Based on this mechanism, the enhanced enrichment by STANM showed an approximately 200-fold microparticle concentration increase compared with the control group of no acoustic enrichment. The in vivo test in mice bladders verifies that the target drug enrichment based on STANM decreased tumor weight by 72.43% compared to traditional chemotherapy. The proposed target drug enrichment method paves the way for enhanced cancer therapy.

Non-contact droplet breakup induced by acoustic potential wells.

BACKGROUNDStricture formation in Crohn’s disease (CD) poses a significant clinical challenge, often requiring differentiation between inflammatory and fibrotic components to guide appropriate therapy.AIMTo evaluate the utility of multimodal intestinal ultrasound - including small intestine contrast ultrasonography (SICUS), contrast-enhanced ultrasound (CEUS), and ultrasound-based elastography - in detecting and characterizing CD-related small bowel strictures.METHODSA review was conducted in accordance with Preferred Reporting Items for Systematic reviews and Meta-Analyses guidelines. A comprehensive search of PubMed and EMBASE databases from inception to June 2025 yielded 697 records, respectively. After screening and full-text assessment, 43 studies were included. Eligible studies reported on the use of SICUS, CEUS, and elastography for detecting or phenotyping CD strictures, with comparisons to cross-sectional imaging, histopathology, endoscopy, or surgical findings.RESULTSAcross heterogeneous study designs, SICUS demonstrated high sensitivity for stricture detection (typically approximately 88%-98%) with specificity that varied by cohort and criteria. Common thresholds included bowel wall thickness > 3 mm, luminal narrowing < 1 cm, and/or prestenotic dilation > 2.5 cm. CEUS effectively distinguished fibrotic from inflammatory strictures using time-intensity curve metrics: Fibrotic strictures showed reduced peak enhancement (e.g., 25 dB vs 38 dB), and lower perfusion area under the curve (AUC) values (e.g., 570 intensity time units vs 1168 intensity time units), reflecting diminished vascularity. Cutoffs such as peak enhancement < 30 dB and AUC < 700 units were associated with fibrosis. Elastography - particularly shear wave elastography achieved AUCs of 0.88-0.91 for fibrosis detection using cutoffs of 2.5-2.9 m/second (sensitivity 80%-88%, specificity 85%-100%). Strain ratio thresholds between 2.2 and 3.0 also differentiated fibrotic from inflammatory lesions with diagnostic AUCs up to 0.91. Among elastography modalities, shear wave elastography consistently outperformed strain elastography and acoustic radiation force impulse in accuracy and reproducibility.CONCLUSIONMultimodal intestinal ultrasound - including SICUS, CEUS, and elastography - offers a comprehensive, radiation-free framework to detect, localize, and phenotype CD strictures. While performance is promising, variability in thresholds and reference standards limits generalizability. Standardized acquisition, predefined cut-offs, and multicenter validation are priorities before widespread adoption in treatment algorithms.

Abstract. The number of ice crystals formed in nascent contrails strongly influences contrail-cirrus life cycle and radiative forcing. Previous studies on contrails from hydrogen combustion focused on microphysical processes that affect the ice crystal number. These studies, however, paid less attention to engine-related aspects. To fill this gap, we investigate how the exhaust plume evolution is thermodynamically influenced by (i) the overall efficiency of propulsion, (ii) the engine exit conditions due to varying ambient conditions, (iii) the engine size and exit jet speed, and (iv) the explicit treatment of kinetic energy dissipation and entrainment of enthalpy initially contained in the bypass flow of a turbofan engine. Based on simulations with the box model version of the Lagrangian Cloud Module, we investigate how these aspects influence the contrail formation process and derive suitable (scaling) relations for the number of ice crystals Nice,f formed on entrained ambient aerosols for hydrogen combustion. We find that the impact of a change in overall efficiency can be mimicked by adjusting the ambient pressure. Moreover, results from scenarios with different engine sizes or jet speeds can be scaled onto each other. Furthermore, for contrail formation on entrained ambient aerosols, a simplified modeling approach is sufficient, assuming that all emitted combustion heat is contained as static enthalpy in the core flow at engine exit. These relations help to derive an expression of Nice,f through a functional relationship that relies on a reduced set of input parameters, while ensuring a generalized parameterization of Nice,f in contrails from hydrogen combustion.

Abstract The boreal forest biome is warming rapidly, impacting disturbance regimes and global climate. Boreal forest fires have intensified, initiating both climate warming (positive) and climate cooling (negative) impacts across spatial and temporal scales. Here we estimate climate impacts from boreal fires in Alaska and western Canada between 2001 and 2019 using integrated net radiative forcing metrics combining greenhouse gas and aerosol emissions from combustion, vegetation recovery, greenhouse gas emissions from fire-induced permafrost thaw and changes in surface albedo over a 70-year period. We find that fires across Alaska contributed, on average, to net climate warming (0.35 ± 4.66 W m −2 of burned area; one standard deviation), while fires across Canada contributed to net cooling (−2.88 ± 4.17 W m −2 of burned area; one standard deviation). Climate-warming fires occur preferentially in dry, high-elevation, steep permafrost landscapes with high pre-fire black spruce coverage and combust more carbon per unit area. Climate-cooling fires are driven by longer spring snow exposure and occur more frequently in continental regions near the treeline. This fine-scale characterization of component and net radiative forcing advances our understanding of the biogeophysical impacts of fires on high-latitude climate and highlights the need to prioritize fire management in carbon-rich permafrost regions to curb long-term warming.

Abstract. The number of ice crystals formed during the contrail's jet phase has a long-lasting impact on the life cycle and radiative forcing of contrail cirrus clouds. For conventional kerosene combustion, suitable parameterizations for early ice crystal number have been developed and employed in general circulation models that are used to estimate the climate impact of contrail cirrus. However, a parameterization for the number of ice crystals formed is lacking for hydrogen combustion. To develop such a parameterization, we present a comprehensive set of contrail formation simulations using the particle-based Lagrangian Cloud Module in a box model approach. Unlike kerosene combustion, no soot particles are emitted. Thus, ice crystals are assumed to form on ambient aerosols entrained into the exhaust plume. The total number of entrained particles primarily governs the nonlinear depletion of water vapor. Consequently, the impact of coarse-mode particles is negligible due to their low abundance. Additionally, ice crystal formation from multiple aerosol populations can be reconstructed from single-population simulations using population-specific properties (size and hygroscopicity) and the total number concentration. We also identify atmospheric conditions where homogeneous droplet nucleation can be safely neglected as potential ice formation pathway. Based on more than 20 000 simulations covering a broad range of atmospheric conditions and aerosol properties, we identify a regime where ice crystal formation becomes nearly independent of ambient relative humidity, aerosol size, and hygroscopicity. Our results provide a basis for a data-driven parameterization of ice crystal number in contrails from hydrogen combustion, to be presented in a companion paper.

Abstract Ice cloud fraction (CF ice ) plays a critical role in the Earth's radiation budget and climate system. However, conventional cloud parameterizations in general circulation models are often inadequate to simulate CF ice and its vertical structure. This study evaluates the Neural Network‐Based Scale‐Adaptive cloud fraction scheme (NSA) in the Taiwan Earth System Model version 1 (TaiESM1), with a focus on its impact on ice cloud simulation and radiative processes. The NSA scheme, trained on CloudSat and ECMWF data, incorporates multiple environmental variables and cloud condensates. Two 10‐year AMIP simulations—one with the default scheme and the other with NSA—were conducted to assess differences in CF ice , cloud radiative forcing, and top‐of‐atmosphere (TOA) radiation. Versus the default scheme, the NSA scheme reduces the global annual mean CF ice , from 29.9% to 25.2%, which is closer to 22.4% based on MODIS‐COSP. The decrease in high‐cloud cover is significant, by 25% globally, and 50% in Antarctica. The NSA scheme also corrects the unrealistic glaciation of low‐level stratus clouds. As a result, the total cloud fraction (CF total ) is reduced from 56.3% to 48.6%, in much better agreement with the CloudSat‐COSP value of 49.8%. The associated changes in cloud radiative forcing and TOA radiation are also calculated to illustrate the effects of these cloud cover changes. Discussion on further improvement of cloud microphysics in TaiESM1 in conjunction with the NSA cloud cover scheme is presented.

Seasonal aerosol variations at the Land-Ocean boundary: Insights from a global AERONET network analysis.

Comparative study of black carbon mixing state characterization: Evaluating Only-SP2 and CPMA-SP2 techniques for enhanced accuracy.

Characterization of vertical confinement of Brownian-diffusive particles within quarter-wavelength ultrasonic standing wave fields in a cylindrical micro-resonator.

Study on acoustic radiation force of a viscoelastic spherical shell in a zero-order Mathieu beam

Amplified Arctic warming can induce strong ecosystem changes with adverse climate feedbacks through greenhouse gas (GHG) release. Shifting plant species and traits with permafrost thaw may contribute to the permafrost carbon feedback. How vegetation dynamics in thawing permafrost systems affect GHG release and how this varies with season, plant species, and soil conditions is poorly understood. Here, we assessed GHG emissions, redox potentials, and geochemical signatures as well as the carbon input in the form of root exudation along a vegetation density gradient and a permafrost thaw gradient over a growing season in Stordalen mire, Sweden. Ecosystem respiration and CH4 emissions increased along the thaw gradient from bog to fen, possibly due to high graminoid root carbon release rates into an anoxic soil, fuelling fast organic matter oxidation and lowering redox potentials to enhance methanogenesis. CH4 emissions increased seven-fold with increasing graminoid cover compared to non-vascular plant controls in the thawed soil. Plants may mediate CH4 transport, which was responsible for 80% of the graminoid-induced increase in CH4 emissions in the bog environment. In the fen environment, graminoid root carbon release stimulated CH4 formation, which dominated by contributing 70% of the graminoid-induced increase. Overall, photosynthesis-related CO2 fixation was substantial in the early and peak growing season, but when expressed as CO2 equivalents, CH4 release offset this uptake, resulting in net positive radiative forcings from graminoid-vegetated thawed soils throughout the growing season. Graminoids increased the net CO2-equivalent flux up to 8.9-fold compared to non-vascular plant locations with the strongest forcing toward late season in graminoid-vegetated fens. Our study showcases how fine-scaled, plant-mediated processes differently contribute to GHG emissions across a thawed bog and fen soil and how the time of growing season can overprint these effects to determine whether the system is a net GHG source or sink.

Abstract Methane (CH 4 ) is a potent greenhouse gas with high radiative forcing and a relatively short atmospheric lifetime of around a decade. We used a decade‐long data set (2011–2022) from the Fourier transform spectrometer at the California Laboratory for Atmospheric Remote Sensing (CLARS‐FTS) to quantify a dramatic increase in methane observed in 2020. We report a significant acceleration of the short‐term growth rate of 1.37 ± 0.20 ppb/month starting in 2020 until the end of 2021, a substantial increase relative to the near‐zero and negative rates of the preceding 4 years (2016–2019). The observed increase in methane concentrations in 2020 is of significant concern due to its potential contribution to global warming. The Total Carbon Column Observing Network (TCCON) is then used to examine the global geospatial variability of the increase in methane. The results suggest an approximately uniform rise in methane globally. Finally, results from a two‐box model used to simulate atmospheric chemical processes of methane production and loss indicate that changes in OH alone are insufficient to explain the rise in atmospheric methane. Recent data from 2022 suggest a deceleration in the methane growth rate, indicating a potential slowdown in the methane increase observed in 2020.

The interhemispheric thermal contrast, defined as the mean sea surface temperature difference between the northern and southern hemispheres, crucially influences tropical climate. Climate models show a positive interhemispheric thermal contrast trend since 1950, with more warming in the northern hemisphere compared to the southern hemisphere, contradicting the observed negative trend. Here we show this discrepancy stems from models overestimating greenhouse gas responses via wind-evaporation-sea surface temperature feedback, while anthropogenic and natural aerosols combine to produce the negative trend in observations. Consequently, models with high equilibrium climate sensitivity exhibit larger discrepancies with observations. Despite model failure to reproduce the trend, the modeled multidecadal interhemispheric thermal contrast variability aligns with observations, enabling a constrained estimate of effective radiative forcing due to aerosol-cloud interactions of , with a "likely" range 57% narrower than the latest IPCC report. Our study further suggests that future northward shifts of the tropical rain belt are likely to be less pronounced than predicted by climate models with high equilibrium climate sensitivity.

Abstract Peristaltic transport phenomena play a crucial role in microscale thermal and biological fluid systems; however, efficient regulation of heat transfer, entropy generation, and microorganism dynamics under combined electromagnetic and radiative effects remains inadequately understood. In this study, peristaltic transport of a conducting fluid in a wavy microchannel is analyzed by incorporating the dynamics of motile microorganisms, quadratic thermal radiation, and Lorentz forces. A nonlinear mathematical framework is formulated to capture the coupled behavior of velocity, temperature, microorganism concentration, and entropy generation, and the resulting system is solved numerically under long-wavelength and low-Reynolds-number assumptions relevant to microfluidic applications. Mathematical models are formulated via incorporating electro-kinetic effects, thermophoresis and Brownian motion, and rheological performance of hyperbolic tangent fluid. The governing nonlinear equations are formulated and solved numerically using a finite element method. The results reveal that the Lorentz force significantly suppresses the axial velocity and enhances flow resistance, leading to a notable reduction in pumping efficiency, while simultaneously increasing entropy generation due to intensified electromagnetic dissipation. Quadratic thermal radiation is found to markedly elevate the temperature field, which in turn amplifies thermal irreversibility and alters the spatial distribution of motile microorganisms. An increase in microorganism concentration strengthens bioconvective effects, stabilizing the flow structure but contributing to higher entropy production through enhanced mass transfer irreversibility.

Dynamic characteristics such as cancer stemness and the epithelial-to-mesenchymal transition (EMT) cause the spread of colorectal cancer (CRC). Although there are now few pharmaceutical approaches, therapeutically correcting these conditions may improve prognosis. Acoustic radiation force and other mechanical ultrasonic forces have become new, noninvasive methods for modifying tumor biology. Nevertheless, little is known about their molecular influence on CRC EMT-stemness pathways. The authors created a simulation pipeline to predict the effects of ultrasound-induced mechanical stress on CRC samples enriched for tumor-infiltrating T cells using transcriptome datasets (GSE108989). Heatmap visualizations, differential expression, pathway enrichment, principal component analysis (PCA), and EMT and stemness scores were computed using bulk RNA-seq. To evaluate mechanistic suppression, signaling axes such as TGF-β, Wnt/β-catenin, Notch, and yes-associated protein (YAP)/transcriptional coactivator with PDZ-binding motif (TAZ) were investigated. The potential ultrasonic sensitivity of key gene modules was assessed. Mesenchymal and stemness-associated transcriptional pathways were found to be downregulated in response to simulated acoustic modulation. Coherent clustering of decreased EMT/stemness genes was shown via heatmaps. Modified tumor groupings were identified by PCA. In the simulated postultrasound condition, canonical pathways associated with invasion, immunological evasion, and stemness maintenance were diminished. These results lend credence to the theory that CRC cellular plasticity may be reprogrammed by mechanical ultrasonic force. Early mechanistic understanding of how acoustic force-based ultrasound may inhibit EMT and stemness in CRC is provided by this transcriptome simulation. This data-driven approach presents ultrasound as a promising supplement to immune-oncology and antimetastatic methods and encourages more in vitro validation.