To reduce water consumption and potential formation damage associated with conventional water-based fracturing fluids while improving the proppant-carrying and flow adaptability of CO2-based systems without relying on specialized CO2 thickeners, a CO2–water polymer hybrid fracturing fluid was developed using an AM/AA copolymer (poly(acrylamide-co-acrylic acid), P(AM-co-AA)) as the thickening agent for the aqueous phase. Systematic experimental investigations were conducted under high-temperature and high-pressure conditions. Fluid-loss tests at different CO2 volume fractions show that the CO2–water polymer hybrid fracturing fluid system achieves a favorable balance between low fluid loss and structural continuity within the range of 30–50% CO2, with the most stable fluid-loss behavior observed at 40% CO2. Based on this ratio window, static proppant-carrying experiments indicate controllable settling behavior over a temperature range of 20–80 °C, leading to the selection of 60% polymer-based aqueous phase + 40% CO2 as the optimal mixing ratio. Rheological results demonstrate pronounced shear-thinning behavior across a wide thermo-pressure range, with viscosity decreasing systematically with increasing shear rate and temperature while maintaining continuous and reproducible flow responses. Pipe-flow tests further reveal that flow resistance decreases monotonically with increasing flow velocity and temperature, indicating stable transport characteristics. Phase visualization observations show that the CO2–water polymer hybrid fracturing fluid system exhibits a uniform milky dispersed appearance under moderate temperature or elevated pressure, whereas bubble-dominated structures and spatial phase separation gradually emerge under high-temperature and relatively low-pressure static conditions, highlighting the sensitivity of phase stability to thermo-pressure conditions. True triaxial hydraulic fracturing experiments confirm that the CO2–water polymer hybrid fracturing fluid enables stable fracture initiation and sustained propagation under complex stress conditions. Overall, the results demonstrate that the AM/AA copolymer-based aqueous phase can provide effective viscosity support, proppant-carrying capacity, and flow adaptability for CO2–water polymer hybrid fracturing fluid over a wide thermo-pressure range, confirming the feasibility of this approach without the use of specialized CO2 thickeners.

Abstract. Estimating runoff components, including surface flow, baseflow and total runoff is essential for understanding precipitation partition and runoff generation and facilitating water resource management. However, a general framework to quantify and attribute runoff components is still lacking. Here, we propose a general formulation through observational data analysis and theoretical derivation based on the two-stage Ponce-Shetty model (named as the MPS model). The MPS model characterizes mean annual runoff components as a function of available water with one parameter. The model is applied over 662 catchments across China and the contiguous United States. Results demonstrate that the model well depicts the spatial variability of runoff components with R2 exceeding 0.81, 0.44 and 0.80 for fitting surface flow, baseflow and total runoff, respectively. The model effectively simulates multi-year runoff components with R2 exceeding 0.97, and the proportion of runoff components relative to precipitation with R2 exceeding 0.94. By using this conceptual model, we elucidate the responses of surface flow and baseflow to available water and environmental factors for the first time. The surface flow is jointly controlled by precipitation and environmental factors, while baseflow is mainly influenced by environmental factors in most catchments. The universal and concise MPS model offers a new perspective on the long-term catchment water balance, facilitating broader application in large-sample investigations without complex parameterizations and providing an efficient tool to explore future runoff variations and responses under changing climate.

The acoustically excited vibrations of a micrometric object in a viscous liquid induce a net fluid flow known as microstreaming. This phenomenon can be harnessed for a variety of microscale applications, including particle transport, fluid mixing and the propulsion of micro-swimmers. Acoustic propulsion holds significant promise for in vivo manipulation due to its inherent biocompatibility and remote actuation capability, eliminating the need for an onboard energy source. However, designing steerable swimmers powered by vibrating tails requires a detailed understanding of the relationship between the input acoustic signal and the resulting streaming flow. In this paper, we characterise experimentally and model the microstreaming generated by a vertically standing micro-cantilever attached to a vibrating plate, as a function of the excitation frequency. Significant streaming is observed only at specific frequencies corresponding to the vibration modes of the support, which both translate and bend the cantilever. Computations based on a two-dimensional semi-analytical model enable quantitative predictions of the in-plane streaming flow structure and velocity magnitude, using as input the cantilever’s vibration profile, fully characterised by laser Doppler vibrometry. In particular, comparison between experiments and simulations allows us to rationalise the frequency-dependent emergence of dipolar, circular and elliptical streaming patterns, which are respectively induced by rectilinear, circular and elliptical translations of the cantilever. This analysis also explains the prevalence of elliptical streaming structures observed in our system. Beyond advancing our fundamental understanding of streaming generated by vibrating slender bodies, these results highlight the potential for frequency-based control of micro-swimmers through predictable, mode-specific flow responses.

Optical coherence tomography (OCT) enables visualization and quantification of the cutaneous microvasculature, yet no study has compared responses to distinct forms of heating in humans. We hypothesized that local skin heating (LH) would evoke larger responses in microvascular diameter, velocity, flow and density than passive whole-body heating (PH) or heated exercise (HE), and that HE responses would exceed PH. Twelve healthy young adults completed four interventions: baseline (33°C; BL), LH, PH (seated) and HE (ergometer cycling) in a climatic chamber (50min, 40°C, 50% relative humidity). OCT was used to quantify microvascular variables immediately after each intervention. Microvascular responses differed across conditions (P<0.001). LH induced the largest responses in all OCT indices (all P<0.001): diameter (67µm), velocity (195µm s-1), flow (687picolitres s-1) and density (56.0%), compared with BL (42µm, 106µm s-1,154picolitress-1 and 26.6%, respectively), PH (45µm, 99µm s-1, 165picolitress-1 and 34.4%, respectively) and HE (49µm, 105µm s-1, 208picolitress-1 and 34.5%, respectively). Although the diameter response was higher after HE (P=0.046), no differences were documented for PH and HE relative to 33°C BL for other OCT measures (all P>0.05). Comparable responses were observed between PH and HE across all variables (all P>0.05). Local heating elicited substantially greater increases in all OCT-derived microvascular metrics compared with PH and HE. Although both PH and HE activate the cutaneous microvasculature, neither stimulus approaches the magnitude of response achieved with local heating. These findings demonstrate that OCT provides quantifiable insights into the distinct ways in which the skin microvasculature responds to different heat exposures.

Mechanically interlocked polymers (MIPs) are a class of polymer structures in which the components are connected by mechanical bonds instead of covalent bonds. We measure the single-molecule rheological properties of polyrotaxanes, daisy chains, and polycatenanes under steady shear and steady uniaxial extension using coarse-grained Brownian dynamics simulations with hydrodynamic interactions. We obtain key rheological features, including tumbling dynamics, molecular extension, stress, and viscosity. By systematically varying structural features, we demonstrate how MIP topology governs flow response. Compared to linear polymers, all three MIP architectures exhibit enhanced tumbling in shear flow, weaker shear thinning, and lower normal stress differences in extensional flow. While polyrotaxanes show higher shear and extensional viscosities, polycatenanes and daisy chains have lower viscosities. In extensional and shear flows, MIPs typically extend more in the flow direction and at weaker flow strengths than linear polymers. These effects arise from the mechanically bonded rings in MIPs, which expand the polymer profile in the gradient direction and increase backbone rigidity due to ring-backbone repulsions. This study provides key insights into MIP flow properties, providing the foundation for their systematic development in engineering applications.

Understanding how nanocomposite gels regulate pore–throat structures and flow behavior is essential for improving profile control and flow diversion in deep-water tight reservoirs. In this study, a dual-structure-regulated nanocomposite gel (DSRC-NCG) was designed, and its structure–flow coupling behavior during gel injection, curing, and degradation was systematically investigated using multiscale flow configurations, including microfluidic models, artificial cores, and sandpack systems. Microstructural evolution and pore–throat connectivity were characterized using μCT imaging, mercury intrusion porosimetry, nitrogen adsorption, and image-based flow simulations, while macroscopic flow responses were evaluated through permeability variation, dominant-channel evolution, injectivity behavior, and quantitative indices including the structure regulation index (SRI) and pore–flow matching index (HCI). The results show that increasing SiO2 content induces a progressive optimization of pore–flow matching by refining critical throats and suppressing preferential flow channels, whereas excessive nanoparticle loading leads to aggregation and attenuation of these effects. This study proposes a multiscale structure–flow coupling framework that quantitatively connects pore–throat regulation with macroscopic flow responses during nanocomposite gel injection and degradation. These findings offer mechanistic insights and practical guidance for the design of nanocomposite gels with improved flow-regulation efficiency and reversibility in deep-water tight reservoir applications.

Magnetic fluid hyperthermia and magnetic drug delivery depend on accurate prediction of ferrofluid transport and heat transfer within tumour-surrounded blood vessels. Motivated by the need for physiologically realistic modelling of such therapies, the current study develops a mathematical model of ferrofluid flow and heat transfer in an inclined cylindrical vessel immersed in tumour tissue, taking into account temperature-dependent thermal conductivity and viscosity, as well as magnetic-field-induced body forces. This novel study integrates inclined flow within tumour-surrounded vessels, non-constant thermophysical properties, and magneto-thermal coupling. With the one-dimensional axisymmetric form of coupled momentum and energy equations, in tumour tissue, we describe a nonlinear thermal and flow response to excitation by a magnetic field. This creates a resulting boundary value problem that is non-dimensionalised using a similarity transformation and solved numerically with MATLAB’s bvp4c, allowing for a parametric study over the inclination angle, ferromagnetic interaction parameter, and nanoparticle concentration. The results show that temperature-dependent properties influence velocity gradients, skin friction, and heat transfer, particularly near the vessel tumour interface. Thermal transport is further intensified by radiative effects and internal heat generation, leading to a notable enhancement of the Nusselt number, while inclination and curvature introduce secondary but non-negligible modifications. Overall, the study provides quantitative insight into magneto-thermal interactions in ferrofluid-based therapies and offers a theoretical basis for improving magnetic hyperthermia and targeted drug delivery strategies.

Photobiomodulation causes an immediate increase in local blood flow. This study aimed to investigate the effect of 890 nm NIR exposure on local skin blood flow in young and middle-aged healthy subjects. In this placebo-controlled clinical trial, 12 young and 12 middle-aged subjects received either continuous or intermittent NIR exposure (890 nm, 5.1 mW/cm2, 4.6 J/cm2, and 35.9 J total energy) on the skin of the upper lateral arm. The continuous exposure experiment, performed in young subjects only, applied 30 min of continuous NIR light. The intermittent exposure experiment, conducted in both age groups, applied NIR light through 10 cycles of 3 min NIR exposure and 2 min OFF (for recording blood flow), resulting in a total duration of 50 min. Laser Doppler flowmetry and thermal images were used to monitor local blood flow and skin temperature. In young subjects, continuous NIR exposure significantly increased blood flow for the first 20 min post-exposure compared to placebo. Further, in young and middle-aged subjects, intermittent exposure increased blood flow during the whole exposure period and 15 min post-exposure. In young subjects, blood flow after continuous NIR exposure was significantly higher than intermittent NIR exposure only for the first 10 min. Comparing intermittent exposure between the two age groups, the blood flow was significantly higher in middle-aged subjects. We conclude that NIR PBM increases local skin blood flow in young and middle-aged subjects. The mode of NIR irradiation and the subjects’ age influenced the local skin blood flow response.

This study aimed to evaluate the feasibility and safety of a novel percutaneous left ventricular assist device CorVad 6.0, for mechanical circulatory support in an ovine model, focusing on device performance, hemocompatibility, and end-organ effects. The CorVad 6.0, which is a microaxial flow pump incorporating an integrated axial-flux motor, was implanted in six healthy sheep via descending aortic access. Animals were supported for 4 weeks, with pump speeds titrated to maintain flows of 1.5-5.0 L/min. All six animals survived the 4 week study period. The CorVad 6.0 was successfully implanted in all subjects with no device-related complications, demonstrating stable operation and a predictable flow response to speed changes. Key hematological and biochemical parameters, including plasma-free hemoglobin, remained within acceptable ranges throughout the study, showing no evidence of significant hemolysis or end-organ dysfunction. Macroscopic and histological analyses of the heart, liver, kidneys, and brain revealed no device-related pathological abnormalities. The CorVad 6.0 demonstrates stable hemodynamic performance and a favorable biocompatibility during a 4 week implantation period. Further study investigating chronic heart failure modes is needed.

Abstract Background: As the most common non-cutaneous form of cancer in males, metastatic prostate cancer is expected to claim the lives of approximately 35,000 Americans in 2025. Notably, the rate of cancer death is highly dependent upon the site of metastasis, and thus the organ site directly affected by this hormone dependent cancer. Despite its prevalence, clinically relevant models recapitulating the histological, phenotypic, and molecular diversity of metastases are scarce and are often done in immune compromised systems. This prevents a detailed evaluation of potential immune effects which is especially relevant in the context of hormone deprivation treatments which may modify immunity. Methods: We have humanized NSG immunocompromised mice that express human Stem Cell Growth Factor, human M-CSF and human IL-3 that have been engrafted with human CD34+ cells (NSG-SGM3). Using both an androgen receptor (AR)-positive adenocarcinoma (PDM136) and a neuroendocrine (NE) prostate cancer (PDMLym1) model, we assessed metastatic properties by inoculating each PDX, via intracardiac injection. Immune engraftment and competence was determined via flow cytometry and response to ovalbumin challenge. Growth of tumors was monitored via bioluminescent imaging of a luciferase transgene expressed in each cell line. Metastatic development was noted in multiple organs. Androgen deprivation was performed before systemic tumor burden exceeded 108 radiance units. Results and Conclusion s: We demonstrate successful adoption of human immune cells in the murine model and the successful growth of tumors at distant metastatic sites. We compared these metastatic tumors to immunocompromised controls, noting differences in human macrophage populations within immunogenic metastatic bone niches before and after removal of testosterone. Given the influence of hormones on immune response in prostate tumors, this immunogenic response varies based on tumor location and hormone exposure. These data provide insight into how we approach combination therapies involving hormone modulation and immune therapies, such as checkpoint inhibition and cytokine traps. Citation Format: John M. Fenimore, Juanjuan Yin, Shana Y. Trostel, Lucas Horn, Ross Lake, Claudia M. Palena, Adam G. Sowalsky. Modeling Human Immune Competent Patient-Derived Metastatic Prostate Cancer in Vivo [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: Innovations in Prostate Cancer Research and Treatment; 2026 Jan 20-22; Philadelphia PA. Philadelphia (PA): AACR; Cancer Res 2026;86(2_Suppl):Abstract nr B021.

A microfluidic approach to probing the first normal stress difference from single-point pressure measurements in transient shear flows is presented. Using an original experimental design, we examine the near-zero-mean pulsatile flow of polymeric solutions in a straight microchannel at low Reynolds and Womersley numbers. An important aspect of this work is that the enhanced fluid elastic stresses can be efficiently determined via the pressure shift measured from pressure-controlled pulsatile shear experiments. We find a scaling law that collapses pressure-shift data from viscoelastic fluids of different molecular weights onto a single master curve that can then be used to predict this phenomenology. Taken together, these results could help shed light on our understanding of the nonlinear normal stress responses in time-dependent flows.

Utilizing saline aquifers for carbon mineralization has proven to be a reliable approach for CO2 storage. However, less attention has been given to CO2 mineralization and geomechanical response at engineering durations and spatial scales. The objective of the study is to evaluate the feasibility of a potential CO2 sequestration site in the Ordos Basin, located at a depth of approximately 1100 m, using the CMG-GEM numerical simulator. A coupled hydraulic–mechanical–chemical model was formulated, accounting for multiphase fluid flow, geochemical reactions, and geomechanical response. The simulation results indicated the following: (1) When CO2 is injected into a saline formation, it can react with minerals. These chemical reactions may lead to the precipitation of certain minerals (e.g., calcite, kaolinite) and the dissolution of others (e.g., anorthite), potentially affecting the porosity and permeability of the storage formation; however, the study found that the effect on porosity is negligible, with only a 1.2% reduction observed. (2) The extent of ground uplift caused by CO2 injection is strongly influenced by the injection rate. The maximum vertical ground displacements after 25 years is 6.1 cm at an injection rate of 16,000 kg/day; when the rate is increased to 24,000 kg/day, the maximum displacement rises to 9.4 cm, indicating a 54% increase.

Quantifying differences between flow fields is a key challenge in fluid mechanics, particularly when evaluating the effectiveness of flow control or other problem parameters. Traditional vector metrics, such as the Euclidean distance, provide straightforward pointwise comparisons but can fail to distinguish distributional changes in flow fields. To address this limitation, we employ optimal transport (OT) theory, which is a mathematical framework built on probability and measure theory. By aligning Euclidean distances between flow fields in a latent space learned by an autoencoder with the corresponding OT geodesics, we seek to learn low-dimensional representations of flow fields that are interpretable from the perspective of unbalanced OT. As a demonstration, we utilise this OT-based analysis on separated flows past a NACA 0012 airfoil with periodic heat flux actuation near the leading edge. The cases considered are at a chord-based Reynolds number of 23 000 and a free-stream Mach number of 0.3 for two angles of attack (AoA) of $6^\circ$ and $9^\circ$ . For each angle of attack, we identify a two-dimensional embedding that succinctly captures the different effective regimes of flow responses and control performance, characterised by the degree of suppression of the separation bubble and secondary effects from laminarisation and trailing-edge separation. The interpretation of the latent representation was found to be consistent across the two AoA, suggesting that the OT-based latent encoding was capable of extracting physical relationships that are common across the different suites of cases. This study demonstrates the potential utility of optimal transport in the analysis and interpretation of complex flow fields.

Fluid-structure interaction analysis of multiphase flow and structural response during parallel water entry of multiple lifeboats

A Patient‐Specific 3D Printed Carotid Artery Model Integrating Vascular Structure, Flow, and Endothelium Responses (Adv. Healthcare Mater. 4/2026)

Satellite monitoring of Greenland wintertime buried lake drainage and potential ice flow response

The present work studies the complex dynamics of an oscillating shock impinging on a laminar/transitional supersonic boundary layer, with emphasis on the radiated post-shock waves and a coherent wave structure induced in the turbulent boundary layer (TBL) downstream of the separation bubble. Fully resolved direct numerical simulations (DNS) have been carried out at Mach 5, with imposed shock-oscillation frequency matching that predicted by earlier direct simulation Monte Carlo (DSMC) studies of the internal shock structure. Shock oscillations are found to produce a field of post-shock waves efficiently transmitted through the reattachment shock into the downstream TBL. The flow response consists of two-dimensional amplified planar waves propagating downstream with sustained amplitude. Increasing shock-oscillation amplitudes progressively enhance this phenomenon, while increasing frequencies, within the DSMC-predicted range, are found to promote a greater disturbance amplification, with amplitudes larger by 50% compared to lower frequencies. This indicates a high susceptibility of the wave transmission mechanism to the shock-oscillation frequencies. Conversely, the region between separation and reattachment shock is found to be sensitive to frequencies different from those of the shock oscillations. This previously unknown generation mechanism of a two-dimensional planar wave system within the TBL is altogether absent when the impinging shock is steady.

Take a breath and get your head around acute altitude adaptations: ventilatory and cerebral blood flow responses to carbon dioxide during hypoxia.

To optimize the flow stability and improve application accuracy of the PWM intermittent variable-rate spraying system, which suffers from insufficient flow stability and response delays during changes in travel speed, this study proposes an intelligent control method based on an improved Adaptive Neural Fuzzy Inference System (ANFIS). Flow characteristic data of the solenoid valve were collected under four pressure conditions (0.2–0.5 MPa), drive frequencies (5–20 Hz), and duty cycles (10–90%) using an indoor test system. An ANFIS controller architecture was constructed with target flow rate and actual travel speed as input variables and PWM frequency-duty cycle combinations as output variables. This controller enhances the traditional single-output mode of ANFIS by achieving multi-output collaborative optimization through shared premise parameters, thereby strengthening the system’s nonlinear modeling and control capabilities. To validate the system’s practical performance, a field simulation test platform based on a spraying robot was constructed. By analyzing preset prescription map information, the system achieved precise variable-rate spraying operations during movement. Test results demonstrate that the steady-state error remains within 5.03% under various speed-varying conditions. This research provides a high-precision intelligent control solution for variable-rate spraying systems, holding significant implications for reducing pesticide application rates and advancing precision agriculture.

To investigate the impact of venous stenting on blood flow and tissue growth, we utilized Computational Fluid Dynamics (CFD) modeling and animal experiments, assessing blood flow and tissue responses over 28 days. Our findings revealed a negative power law correlation, with low wall shear stress (WSS) identified as the primary driver of accelerated tissue growth. Unlike the focal narrowing typically observed in stented arteries, venous tissue growth exhibited greater variability. Additionally, the threshold for low WSS that triggered growth was smaller than previously reported in arteries. This study provides new insights into venous neointimal hyperplasia, emphasizing the need to consider venous-specific responses in stent-electrode design and clinical applications. Nonetheless, potential risks such as thrombosis and inflammatory responses should be further investigated to fully understand the long-term viability of these devices. Understanding the biomechanical environment of stents in cerebral veins can guide the development of next-generation neural interfaces and inform clinicians and device developers about potential impacts on long-term outcomes.