Understanding xylem embolism formation is challenging due to dynamic changes and multiphase interactions in conduits. Here, we hypothesise that embolism spread involves gas diffusion in xylem, and is affected by time. We measured hydraulic conductivity (Kh) in flow-centrifuge experiments over 1 h at a given pressure and temperature for stem samples of three angiosperm species. Temporal changes in Kh at 5, 22, and 35°C, and at various pressures were compared to modelled gas concentration changes in a recently embolised vessel in the centre of a centrifuge sample. Temporal changes in Kh were logarithmic and species-specific. Maximum relative increases of Kh between 6% and 40% happened at 22°C for low centrifugal speed (<3250 RPM), while maximum decreases between 41% and 61% occurred at higher speeds. These reductions in Kh were experimentally shown to be associated with a temporal increase of embolism at the centre of centrifuge samples, which was likely associated with gas concentration increases in recently embolized vessels. Although embolism is mostly pressure-driven, our experimental and modelled data indicate that time, conduit characteristics, and temperature are involved due to their potential role in gas diffusion. Gas diffusion, however, does not seem to cover the entire process of embolism spread.

UNASSIGNED: To characterize the gas production phenomenon in the animal model of left ventricular assist device (LVAD), and study its mechanism.
UNASSIGNED: An in vitro bubble precipitation experiment was conducted, and the blood samples of Parma spp. animals were divided into ordinary group and oxygen-enriched group according to whether they were oxygenated or not at the time of blood collection, and a static control group was set up respectively. Blood gases were drawn and analyzed before and after the experiment. Activate the pump, and the number of air bubbles in the loop was measured by ultrasound at different rotational speeds; CFD was applied to simulate the flow field in the blood pump, and pressure, fluid velocity vector and shear force diagrams were plotted, and a thrombus model was constructed and the flow field was simulated and plotted as a cloud diagram.
UNASSIGNED: There was a statistical difference in the number of bubbles in the inflow and outflow tubes of the blood pump (P values of 0.04 and 0.023, respectively), and the number of bubbles in the outflow tubes of both groups was significantly higher than the number of bubbles in the inflow tubes. The number of bubbles in the tubes of both the oxygen-enriched and normal groups was significantly higher than that in the inflow group. In both the normal and oxygen-enriched groups, more gas was produced at higher speeds than at lower speeds. Blood gas analysis showed that the reduced gas composition in the blood was mainly oxygen. Flow field simulation results: the high rotation speed group had lower central pressure and greater scalar shear. The thrombus simulation group was more prone to turbulence, sudden pressure changes, and greater shear than the normal group.
UNASSIGNED: Blood gas production is associated with higher partial pressures of blood oxygen, higher rotation speed, and intrapump thrombosis, and the mechanism of pump gas production is degassing of dissolved gases rather than cavitation of water, and the gas released is most likely to have oxygen. The degassing phenomenon is an warning factor for pump thrombosis.

The tumor microenvironment is increasingly acknowledged as a critical contributor to cancer progression, mediating genetic and epigenetic alterations. Beyond diverse cellular interactions from the microenvironment, physicochemical factors such as tumor acidosis also significantly affect cancer dynamics. Recent research has highlighted that tumor acidosis facilitates invasion, immune escape, metastasis, and resistance to therapies. Thus, noninvasive measurement of tumor acidity and the development of targeted interventions represent promising strategies in oncology. Techniques like contrast-enhanced ultrasound (CEUS) can effectively assess blood perfusion, while ultrasound-stimulated microbubble cavitation (USMC) has proven to enhance tumor blood perfusion. We therefore aimed to determine whether CEUS assesses tumor acidity and whether USMC treatment can modulate tumor acidity. Firstly, we tracked CEUS perfusion parameters in MCF7 tumor models and compared them with in vivo tumor pH recorded by pH microsensors. We found that the peak intensity and area under curve of tumor contrast-enhanced ultrasound correlated well with tumor pH. We further conducted USMC treatment on MCF7 tumor-bearing mice, tracked changes of tumor blood perfusion and tumor pH in different perfusion regions before and after the USMC treatment to assess its impact on tumor acidity and optimize therapeutic ultrasound pressure. We discovered that USMC with 1.0 Mpa significantly improved tumor blood perfusion and tumor pH. Furthermore, tumor vascular pathology and PGI2 assays indicated that improved tumor perfusion was mainly due to vasodilation rather than angiogenesis. More importantly, analysis of glycolysis-related metabolites and enzymes demonstrated USMC treatment can reduce tumor acidity by reducing tumor glycolysis. These findings support that CEUS may serve as a potential biomarker to assess tumor acidity and USMC is a promising therapeutic modality for reducing tumor acidosis.

OBJECTIVE: Perfluorocarbon nanodroplets (NDs) have been widely investigated as both diagnostic and therapeutic agents. There remains, however, a challenge in generating NDs that do not vaporize spontaneously but can be activated at ultrasound pressures that do not produce unwanted bioeffects. In previous work, it has been shown that phospholipid-coated perfluorobutane (PFB) NDs can potentially overcome this challenge. The aim of this study was to investigate whether these NDs can promote drug delivery.
METHODS: A combination of high-speed optical imaging and passive cavitation detection was used to study the acoustic properties of the PFB-NDs in a tissue mimicking phantom. PFB-NDs were exposed to ultrasound at frequencies from 0.5 to 1.5 MHz and peak negative pressures from 0.5 to 3.5 MPa. In addition, the penetration depth of two model drugs (Nile Red and 200 nm diameter fluorescent polymer spheres) into the phantom was measured.
RESULTS: PFB NDs were found to be stable in aqueous suspension at both 4°C and 37°C; their size remaining unchanged at 215 ± 11 nm over 24 h. Penetration of both model drugs in the phantom was found to increase with increasing ultrasound peak negative pressure and decreasing frequency and was found to be positively correlated with the energy of acoustic emissions. Extravasation depths >1 mm were observed at 0.5 MHz with pressures <1 MPa.
CONCLUSIONS: The results of the study thus suggest that PFB NDs can be used both as drug carriers and as nuclei for cavitation to enhance drug delivery without the need for high intensity ultrasound.

Lichens are a mutualistic symbiosis between a fungus and one or more photosynthetic partners. They are photosynthetically active during desiccation until relative water contents (RWC) as low as 30% (on dry mass). Experimental evidence suggests that during desiccation, the photobionts have a higher hydration level than the surrounding fungal pseudo-tissues. Explosive cavitation events in the hyphae might cause water movements towards the photobionts. This hypothesis was tested in two foliose lichens by measurements of ultrasonic acoustic emissions (UAE), a method commonly used in vascular plants but never in lichens, and by measurements of photosystem II efficiency, water potential and RWC. Thallus structural changes were characterised by low-temperature scanning electron microscopy. The thalli were silent between 380% and 30% RWCs, i.e. when explosive cavitation events should cause movements of liquid water. Nevertheless, the thalli emitted UAE at approximately 5% RWC. Accordingly, the medullary hyphae were partially shrunk at about 15% RWC, whereas they were completely shrunk below 5% RWC. These results do not support the hypothesis of hyphal cavitation and suggest that the UAE originate from structural changes at hyphal level. The shrinking of hyphae is proposed as an adaptation to avoid cell damage at very low RWCs.

The nicotinamide adenine dinucleotide phosphate (NADPH) oxidase 4 (NOX4) protein plays an essential role in the cisplatin (CDDP)-induced generation of reactive oxygen species (ROS). In this study, we evaluated the suitability of ultrasound-mediated lysozyme microbubble (USMB) cavitation to enhance NOX4 siRNA transfection in vitro and ex vivo. Lysozyme-shelled microbubbles (LyzMBs) were constructed and designed for siNOX4 loading as siNOX4/LyzMBs. We investigated different siNOX4-based cell transfection approaches, including naked siNOX4, LyzMB-mixed siNOX4, and siNOX4-loaded LyzMBs, and compared their silencing effects in CDDP-treated HEI-OC1 cells and mouse organ of Corti explants. Transfection efficiencies were evaluated by quantifying the cellular uptake of cyanine 3 (Cy3) fluorescein-labeled siRNA. In vitro experiments showed that the high transfection efficacy (48.18%) of siNOX4 to HEI-OC1 cells mediated by US and siNOX4-loaded LyzMBs significantly inhibited CDDP-induced ROS generation to almost the basal level. The ex vivo CDDP-treated organ of Corti explants of mice showed an even more robust silencing effect of the NOX4 gene in the siNOX4/LyzMB groups treated with US sonication than without US sonication, with a marked abolition of CDDP-induced ROS generation and cytotoxicity. Loading of siNOX4 on LyzMBs can stabilize siNOX4 and prevent its degradation, thereby enhancing the transfection and silencing effects when combined with US sonication. This USMB-derived therapy modality for alleviating CDDP-induced ototoxicity may be suitable for future clinical applications.

UNASSIGNED: The present study aimed to construct and validate a nomogram based on clinical metrics to identify CPTB.
UNASSIGNED: The present study retrospectively recruited pulmonary tuberculosis (PTB) patients admitted to Jiashan County First People\'s Hospital in China from November 2018 to September 2023. PTB patients were classified into the CPTB group and the non-CPTB group based on chest computed tomography findings, and were randomly allocated to the training set (70%) and the validation cohort (30%). The training set and validation set were used to establish and validate nomogram, respectively. Multivariate logistic regression analysis (MLSA) was used to identify the independent risk factors for CPTB in patients with PTB. Statistically significant variables in the MLSA were then used to construct a nomogram predicting CPTB in patients with PTB. The receiver operating characteristic (ROC) curve, calibration curve analysis (CCA), and decision curve analysis (DCA) were used for the evaluation of the nomogram.
UNASSIGNED: A total of 293 PTB patients, including 208 in the training set (85 CPTB) and 85 in the validation set (33 CPTB\\), were included in this study. Stepwise MLSA showed that sputum smear (≥2+), smoking(yes), glycosylated hemoglobin A1c(HbA1c), hemoglobin (HB), and systemic inflammatory response index (SIRI) were independent risk factors for the development of cavitation in patients with PTB. The nomogram identifying the high-risk CPTB patients was successfully established and showed a strong predictive capacity, with area under the curves (AUCs) of 0.875 (95% CI:0.806-0.909) and 0.848 (95% CI:0.751-0.946) in the training set and validation set respectively. In addition, the CCA and DCA corroborated the nomogram\'s high level of accuracy and clinical applicability within both the training and validation sets.
UNASSIGNED: The constructed nomogram, consisting of sputum smear positivity, smoking, HbA1C, HB, and SIRI, serves as a practical and effective tool for early identification and personalized management of CPTB.

UNASSIGNED: Drought-induced embolism formation in conifers is associated with several tracheid and pit traits, which vary in parallel from stem apex to base. We tested whether this axial anatomical variability is associated with a progressive variation in embolism vulnerability along the stem from apex to base.
UNASSIGNED: We assessed the tracheid hydraulic diameter (Dh), mean pit membrane area (PMA) and the xylem pressure at 50% loss of conductivity (P50) on longitudinal stem segments extracted at different distances from the stem apex (DFA) in a Picea abies and an Abies alba tree.
UNASSIGNED: In both trees, Dh and PMA scaled with DFA 0.2. P50 varied for more than 3 MPa from the treetop to the stem base, according to a scaling of -P50 with DFA-0.2 . The largest Dh, PMA and P50 variation occurred for DFA<1.5 m. PMA and Dh scaled more than isometrically (exponent b=1.2). Pit traits vary proportionally with tracheid lumen diameter.
UNASSIGNED: Apex-to-base trends in tracheid and pit traits, along with variations in P50, suggest a strong structure-function relationship that is influenced by DFA. Although the effect of DFA on P50 has not been extensively explored previously, we propose that analyzing the relationship between P50 and DFA could be crucial for a comprehensive assessment of embolism vulnerability at the individual level.

Resource allocation theory posits that organisms distribute limited resources across functions to maximize their overall fitness. In plants, the allocation of resources among maintenance, reproduction, and growth influences short-term economics and long-term evolutionary processes, especially during resource scarcity. The evolution of specialized structures to divide labor between reproduction and growth can create a feedback loop where selection can act on individual organs, further increasing specializaton and  resource allocation. Ferns exhibit diverse reproductive strategies, including dimorphism, where leaves can either be sterile (only for photosynthesis) or fertile (for spore dispersal). This dimorphism is similar to processes in seed plants (e.g., the production of fertile flowers and sterile leaves), and presents an opportunity to investigate divergent resource allocation between reproductive and vegetative functions in specialized organs. Here, we conducted anatomical and hydraulic analyses on Onoclea sensibilis L., a widespread dimorphic fern species, to reveal significant structural and hydraulic divergences between fertile and sterile leaves. Fertile fronds invest less in hydraulic architecture, with nearly 1.5 times fewer water-conducting cells and a nearly 0.5 times less drought-resistant xylem compared to sterile fronds. This comes at the increased relative investment in structural support, which may help facilitate spore dispersal. These findings suggest that specialization in ferns-in the form of reproductive dimorphism-can enable independent selection pressures on each leaf type, potentially optimizing spore dispersal in fertile fronds and photosynthetic efficiency in sterile fronds. Overall, our study sheds light on the evolutionary implications of functional specialization and highlights the importance of reproductive strategies in shaping plant fitness and evolution.

The Doppler ultrasound twinkling artifact, a rapid color shift, appears on pathological mineralizations and is theorized to arise from scattering off micron-sized crevice microbubbles. However, the influence of crevice number and size as well as the bubble dynamics on twinkling is not well-understood. Cylinders with diameters of 0.8-1.2 µm and depths of 1 µm were etched into a silicon wafer and crevice bubbles were driven at 0.75, 2.5, and 5.0 MHz while monitoring with high-speed photography. Experimental results were compared to a derived crevice bubble model. On three separate wafers, cylindrical crevices (10 or 100) with diameters of 1, 10, or 100 µm and depths of 10 µm were etched and imaged with a research ultrasound system in Doppler mode at 5, 7.8, and 18.5 MHz. Within the pressure ranges studied here (∼1MPa), no bubble oscillation was observed for the 0.8-1.2 µm crevice bubbles which matched computational results. Crevices with 1 and 10 µm diameters produced more twinkling than 100 µm crevices at 5 and 7.8 MHz. In contrast, 100 µm crevices produced more twinkling than 1 or 10 µm crevices at 18.5 MHz (p < 0.001 in all cases). These results provide better insight into how crevice bubbles cause twinkling on pathological mineralizations.