capillary pressure

Skin color observation provides a simple and non-invasive method to estimate the health status of patients. Capillary Refill Time (CRT) is widely used as an indicator of pathophysiological conditions, especially in emergency patients. While the measurement of CRT is easy to perform, its evaluation is highly subjective. This study proposes a method to aid quantified CRT measurement using an RGB camera. The procedure consists in applying finger compression to the forearm, and the CRT is calculated based on the skin color change after the pressure release...

PURPOSE: This study explored the relationship among microvascular parameters as delineated by optical coherence tomography angiography (OCTA) and retinal perfusion. Here, we introduce a versatile framework to examine the interplay between the retinal vascular structure and function by generating virtual vasculatures from central retinal vessels to macular capillaries. Also, we have developed a hemodynamics model that evaluates the associations between vascular morphology and retinal perfusion...

The sensitivity of the miniature mass spectrometer (mini-MS) is largely restricted by the ion transmission in rough vacuum region. Even though various "in-line" ion transfer devices have improved mini-MS sensitivity, the severe dynamic gas is still weakening the efficiency of ion transmission in this region. Inspired by the "off-axis" ion funnel design in the lab-scale mass spectrometers, a miniature orthogonal injection ion funnel (MO-IF) was developed in this study for the mini-MS with a continuous atmospheric pressure interface...

HYPOTHESIS: Microcapsules with osmotically-inflated elastic shells exhibit an ultrafast release of encapsulants while mechanically stimulating the microenvironments, akin to popping balloons. EXPERIMENTS: To prepare elastic shells with uniform thickness and size, monodisperse water-in-oil-in-water (W/O/W) double-emulsion drops are produced in a capillary microfluidic device. The polydimethylsiloxane (PDMS)-containing oil phase is thermally cured to create the elastic shell...

Diastolic dysfunction arising from alterations in myocardial structure and/or function is a central component of several cardiovascular disorders, including heart failure with preserved ejection fraction (HFpEF). Basic research aimed at understanding underlying mechanisms contributing to the development of diastolic dysfunction has generally centered upon models of left ventricular (LV) hypertrophy arising from persistent and severe elevations in myocardial afterload (e.g., aortic banding). Mechanisms of hypertrophy-independent diastolic dysfunction, on the other hand, have received less attention, even though overt anatomic LV hypertrophy is absent in many HFpEF patients...

The efficient removal of droplets on solid surfaces holds significant importance in the field of fog collection, condensation heat transfer, and so on. However, on current typical surfaces, droplets are characterized by a passive and single removal mode, contingent on the traction force (e.g., capillary force, Laplace pressure, etc.) generated by the surface's physics and chemistry design, posing challenges for enhancing the efficiency of droplet removal. In this paper, an effective active strategy based on different removal modes is demonstrated on magnetic responsive polydimethylsiloxane (PDMS) superhydrophobic microplates (RM-MPSM)...

In Proton Exchange Membrane Fuel Cells (PEMFCs), the presence of residual water within the Gas Diffusion Layer (GDL) poses challenges during cold starts and accelerates degradation. A computational model based on the Lattice Boltzmann Method (LBM) was developed to consider the capillary pressure inside the PEMFC and to analyze the exact geometries of the GDLs, which were obtained using the Computed Tomography scan. The novelty of this study is to suggest a methodology to compare the quantitative water removal performance of the GDLs without long-term experimental testing...

Aqueous phase trapping (APT), which is one of the most prominent damages, seriously restricts the natural gas production in tight gas sandstone with low permeability. Pore size and microscopic pore structures are the most important factors to determine the water blocking damage. In this paper, 9 core samples from tight gas sandstone with various physical properties were employed, and the pore size distribution (PSD) of the core samples were investigated by high pressure mercury intrusion tests (HPMI). Results showed that the porosity of core samples ranges from 5...

Pulmonary hypertension (PH) can arise from several distinct disease processes, with a percentage presenting with combined pre- and postcapillary pulmonary hypertension (cpcPH). Patients with cpcPH are unsuitable candidates for PH-directed therapies due to elevated pulmonary capillary wedge pressures (PCWPs); however, the PCWP is dynamic and is affected by both preload and afterload. Many patients that are diagnosed with cpcPH are hypertensive at the time of right heart catheterization which has the potential to increase the PCWP and, therefore, mimic a more postcapillary-predominant phenotype...

BACKGROUND: Janus kinase (JAK) inhibitors constitute a novel class of oral biologic disease-modifying antirheumatic drugs for patients with rheumatoid arthritis (RA). However, their use has been associated with increased risk of major cardiovascular events. We investigated whether treatment with JAK inhibitors exerts significant alterations in the micro- and microvasculature in RA patients. METHODS: Thirteen patients with RA initiating treatment with JAK inhibitors were prospectively studied...

Recent experiments have revealed that the macroscopic Kelvin equation remains surprisingly accurate even for nanoscale capillaries. This phenomenon was so far explained by the oscillatory behavior of the solid-liquid interfacial free energy. We here demonstrate thermodynamic and capillarity inconsistencies with this explanation. After revising the Kelvin equation, we ascribe its validity at nanoscale confinement to the effect of disjoining pressure. To substantiate our hypothesis, we employed molecular dynamics simulations to evaluate interfacial heat transfer and wetting properties...

The kidneys maintain fluid-electrolyte balance and excrete waste in the presence of constant fluctuations in plasma volume and systemic blood pressure. The kidneys perform these functions to control capillary perfusion and glomerular filtration by modulating the mechanisms of autoregulation. An effect of these modulations are spontaneous, natural fluctuations in nephron perfusion. Numerous other mechanisms can lead to fluctuations in perfusion and flow. The ability to monitor these spontaneous physiological fluctuations in vivo could facilitate the early detection of kidney disease...

Background: The evaluation of volume status is essential to clinical decision-making, yet multiple studies have shown that physical exam does not reliably estimate a patient's intravascular volume. Venous excess ultrasound score (VExUS) is an emerging volume assessment tool that utilizes inferior vena cava (IVC) diameter and pulse-wave Doppler waveforms of the portal, hepatic and renal veins to evaluate venous congestion. A point-of-care ultrasound exam initially developed by Beaubein-Souligny et al., VExUS represents a reproducible, non-invasive and accurate means of assessing intravascular congestion...

PURPOSE: To evaluate the influence of systemic factors on macular vessel density in quantitative Optical Coherence Tomography Angiography (OCTA) by sex. STUDY DESIGN: A cross-sectional study. METHODS: A total of 2018 adults were recruited in this study. Participants were excluded (n=964) due to missing data, eye-related problems, or low OCTA scan quality. Macular vessel densities were measured with OCTA using split-spectrum amplitude decorrelation angiography algorithm...

We propose a thermodynamic model that combines the Young-Laplace equation and perturbed chain-statistical associating fluid theory (PC-SAFT) equation of state to estimate capillary condensation pressure in microporous and mesoporous sorbents. We adjust the PC-SAFT dispersion-energy parameter when the pore size becomes comparable to the molecular dimension. This modelling framework is applied to diverse systems containing associating and non-associating gases, various sorbents, and a wide range of temperatures...

BACKGROUND: In acute respiratory distress syndrome (ARDS), respiratory drive often differs among patients with similar clinical characteristics. Readily observable factors like acid-base state, oxygenation, mechanics, and sedation depth do not fully explain drive heterogeneity. This study evaluated the relationship of systemic inflammation and vascular permeability markers with respiratory drive and clinical outcomes in ARDS. METHODS: ARDS patients enrolled in the multicenter EPVent-2 trial with requisite data and plasma biomarkers were included...

If glaucoma damage develops despite normal intraocular pressure or if the damage progresses despite well-controlled intraocular pressure, we usually find other risk factors. One important group are the vascular factors. We should focus not only on the classical risk factors of atherosclerosis, such as arterial hypertension or dyslipidaemia, but also on dysregulation of blood flow, especially on primary vascular dysregulation (PVD). Low blood pressure, either current or in adolescence, low body mass index or frequently cold hands and feet may provide important hints...

Capillary flow has garnered significant attention due to its unique dynamic characteristics that require no external force. Creating a quantitative analytical model to evaluate capillary flow behaviors in root-like networks is essential for enhancing fluid control properties in functional textiles. In this study, we explore the capillary dynamics within root-like networks under the influence of gravity and derive the most rapid capillary flow via structural optimization. The flow time in a capillary is dominated by the capillary pressure, viscous pressure loss, and gravity, each of which exhibits diverse sensitivities to the structures of root-like networks...

Plentiful studies have clarified miRNAs take on a key role in the sexual dysfunction of diabetic rats. This study aimed to figure out microRNA (miR)-503-5p/SYDE2 axis' latent mechanisms in streptozotocin-induced diabetic rat sexual dysfunction. A model of erectile dysfunction (ED) in diabetic rats was established by injecting streptozotocin. MiR-503-5p and SYDE2 in ED rats were altered by injection of miR-503-5p mimic or si/oe-SYDE2. The targeting link between miR-503-5p and SYDE2 was testified. ICP/MAP value was tested by pressure sensor; Penile capillary abundance was assessed; Penile cGMP and AGEs were detected; penile smooth muscle cell apoptosis was assessed; MiR-503-5p and SYDE2 were tested...

High-order harmonic generation (HHG) arising from the nonperturbative interaction of intense light fields with matter constitutes a well-established tabletop source of coherent extreme-ultraviolet and soft X-ray radiation, which is typically emitted as attosecond pulse trains. However, ultrafast applications increasingly demand isolated attosecond pulses (IAPs), which offer great promise for advancing precision control of electron dynamics. Yet, the direct generation of IAPs typically requires the synthesis of near-single-cycle intense driving fields, which is technologically challenging...