Pressure Modulation Research Articles

Lumen Pressure Modulation in Chicken Embryos.

Pressure exerted by fluid contained within a lumen plays a crucial role in the growth, morphogenesis, and patterning of epithelial organs. Accurate modulation of lumen pressure in the developing embryo requires sensitive and robust methods that can detect and vary pressure in the range of tens to hundreds of Pascals (Pa). Here we describe a simple, cost-effective protocol for setting up a pressure modulation apparatus combining a high-sensitivity pressure sensor and a water column whose height can be finely tuned. We demonstrate lumen pressure control using the developing brain of early chicken embryos.

Biomimetic Curved Artificial Compound Eyes: A Review

Natural compound eyes (NCEs) are the most abundant and successful eye designs in the animal kingdom. An NCE consists of a number of ommatidia, which are distributed along a curved surface to receive light. This curved feature is critical to the functions of NCE, and it ensures that different ommatidia point to slightly different directions and thus enables panoramic vision, depth perception, and efficient motion tracking while minimizing aberration. Consequently, biomimetic curved artificial compound eyes (BCACEs) have garnered substantial research attention in replicating the anatomical configuration of their natural counterparts by distributing ommatidia across a curved surface. The reported BCACEs could be briefly categorized into 2 groups: fixed focal lengths and tunable focal lengths. The former could be further subcategorized into simplified BCACEs, BCACEs with photodetector arrays within curved surfaces, and BCACEs with light guides. The latter encompasses other tuning techniques such as fluidic pressure modulation, thermal effects, and pH adjustments. This work starts with a simple classification of NCEs and then provides a comprehensive review of main parameters, operational mechanisms, recent advancements, fabrication methodologies, and potential applications of BCACEs. Finally, discussions are provided on future research and development. Compared with other available review articles on artificial compound eyes, our work is distinctive since we focus especially on the “curved” ones, which are difficult to fabricate but closely resemble the architecture and functions of NCEs, and could potentially revolutionize the imaging systems in surveillance, machine vision, and unmanned vehicles.

Using blast energy as an effective technology to provide subgrade stability in road construction

Drilling and blasting technology is considered to be one of the most efficient and cost-effective ways to increase the bearing capacity of soft soils which form the subgrade of road embankments. This study investigates blast energy as a means of creating vertical sand drains in a section of Moscow-Saint-Petersburg Motorway M-11 (construction 2018) which crosses the Kolomenka River and is located in a swampy area. Geophysical and geological engineering tests were conducted, they included monitoring of pore pressure modification in soft soils as well as geodetic monitoring of settlement levels. The findings showed that the applied technology quickly allowed a large bulk of sandy soils (more than 500 thousand cubic meters) to compact in the subgrade of the road as a result of generation of excessive pore pressure. No other technology could have been used due to the presence of an embedded bulk of soft soils and swampiness of the site. Decreasing deformations of the subgrade and CPTU data revealed that the subgrade of the road embankment was compacted. This fact was also confirmed by geophysical tests. Drilling and blasting technology is very effective from an ecological and economic perspective in comparison with other technologies. In addition, this study highlights the importance of preserving swamp systems in order to protect river sources.

Portosystemic shunting prevents hepatocellular carcinoma in non-alcoholic fatty liver disease mouse models.

Non-alcoholic fatty liver disease (NAFLD) is one of the leading cause of hepatocellular carcinoma (HCC). This association is supported by the translocation of bacteria products into the portal system, which acts on the liver through the gut-liver axis. We hypothesize that portosystemic shunting can disrupt this relationship, and prevent NAFLD-associated HCC. HCC carcinogenesis was tested in C57BL/6 mice fed a high-fat high-sucrose diet (HFD) and injected with diethylnitrosamine (DEN) at two weeks of age, and in double transgenic LAP-tTA and TRE-MYC (LAP-Myc) mice fed a methionine-choline-deficient diet. Portosystemic shunts were established by transposing the spleen to the sub-cutaneous tissue at eight weeks of age. Spleen transposition led to a consistent deviation of part of the portal flow and a significant decrease in portal pressure. It was associated with a decrease in the number of HCC in both models. This effect was supported by the presence of less severe liver steatosis after 40 weeks, and lower expression levels of liver fatty acid synthase. Also, shunted mice exhibited lower liver oxygen levels, a key factor in preventing HCC as confirmed by the development of less HCCs in mice with hepatic artery ligation. The present data show that portosystemic shunting prevents NAFLD-associated HCC, utilizing two independent mouse models. This effect is supported by the development of less steatosis, and a restored liver oxygen level. Portal pressure modulation and shunting deserve further exploration as potential prevention/treatment options for NAFLD and HCC.

Wireless Micropump and Pressure Monitoring System for Inducing Bone Formation Through Intramedullary Pressure Modulation

Wireless Micropump and Pressure Monitoring System for Inducing Bone Formation Through Intramedullary Pressure Modulation

Relationships among gut microbes, the interleukin family, and hypertension: a mediation Mendelian randomization study

PurposeObservational studies have increasingly recognized the influence of gut microbes on blood pressure modulation. Despite these findings, a direct causal link between gut flora and hypertension remains unestablished due to inherent confounders and the challenges of reverse causality in observational research. In this study, we sought to elucidate the causal relationship between specific gut flora and hypertension and its intermediary mediators.MethodsWe employed a two-sample Mendelian randomization (MR) and mediation MR analysis, analyzing 211 species of gut bacteria, with a focus on the interleukin family as potential mediators and hypertension as the primary outcome. The central methodological technique was inverse variance-weighted estimation, supplemented by various other estimators.ResultsOur findings revealed that two bacterial species positively correlated with hypertension risk, while five exhibited a negative association. Further validation was conducted using sensitivity analyses. Notably, our mediation MR results suggest interleukin-1 receptor type 2 (IL-1R2) as a mediator for the effect of the genus Clostridium innocuum group on hypertension, accounting for a mediation proportion of 14.07% [mediation effect: (b = 0.0007, 95%CI: 0.0002–0.0011); proportion mediation = 14.07% (4.26–23.40%)].ConclusionOur research confirms a genetic causal relationship between specific gut microbes and hypertension, emphasizing the potential mediating role of interleukin-1 receptor type 2 (IL-1R2) and offering insights for clinical hypertension interventions.

Post-Harvest Atmospheric Pressure and Composition Modify the Concentration and Bioaccessibility of α- and β-Carotene in Carrots and Sweet Potatoes.

Provitamin A (proVA) carotenoid synthesis and degradation are strongly influenced by environmental factors, including during post-harvest storage. Hypobaric and hyperbaric storages increase the shelf-life of many crops, but their effects on proVA carotenoids are not known. Our aim was to investigate the effects of modifications of atmospheric pressure and composition on α- and β-carotene concentration and bioaccessibility during the post-harvest storage of carrots and sweet potatoes. Vegetables were stored for 11-14 days at 20 °C in the dark in chambers with modified pressure and O2 concentrations. In carrots, α- and β-carotene concentrations increased significantly during storage, but compared to the control, they were significantly lower in hyperbaria (-23 and -26%, respectively), whereas they did not differ significantly in hypoxia and hypobaria. In sweet potatoes, α- and β-carotene concentrations decreased significantly during storage, but neither hypoxia, hypobaria nor hyperbaria led to any significant change compared to the control. There was a significant increase for carrot α- and β-carotene bioaccessibility in hypobaria and hyperbaria, while there was a significant decrease for sweet potato β-carotene bioaccessibility in hypobaria/hypoxia and normobaria/hypoxia (-45% and -65% vs. control, respectively). Atmospheric pressure and composition during the post-harvest storage of carrots and sweet potatoes modified the concentration and bioaccessibility of proVA carotenoids.

A novel textile drying technique via pulsed vacuum method

Drying is a time-consuming and energy-intensive process linked to environmental thermodynamic properties. Conventional methods often use high temperatures for long durations, potentially harming textiles. This article introduces an innovative vacuum textile drying technique utilizing pressure pulsation. Experimental validation reveals that pulsed vacuum drying (PVD) accelerates drying rates and lowers operational temperatures for cotton samples. Compared to constant vacuum drying, PVD achieves a 23% faster reduction to 5% moisture content while maintaining quality. PVD reduces drying temperature from 80 to 60 °C for the same drying time at atmospheric pressure. This article presents a numerical model to analyze fabric drying properties. Simulation results align with experimental results, with deviations in a range of 10 °C for critical temperatures and 2% for moisture content and drying time. The experimental and computational results helped to identify dryer performance key variables: chamber pressure, temperature, and vacuum pulse modulation. A series of experiments reveal optimized vacuum modulation that enhances average drying rate and minimizes drying time.

Dual-phase La0.5Sr0.5Fe0.8Co0.2O3−δ-Ce0.8Sm0.2O2-δ hollow fiber membranes for oxygen separation

In this work, the dual-phase La0.5Sr0.5Fe0.8Co0.2O3-δ-Ce0.8Sm0.2O2-δ (LSCF-SDC) (65–35 wt%) hollow fiber membranes were prepared via combined method of phase inversion and sintering technique. In situ X-ray diffraction (XRD) experiments showed that the structure of LSCF-SDC is stable in air and vacuum (pO2 ∼ 10−4 atm) in the temperature range of 30–900 °C. Moreover, the effect of temperature, oxygen partial pressure and surface modification on the oxygen fluxes across LSCF-SDC hollow fiber membranes were studied. The results obtained indicate that the oxygen fluxes through dual-phase LSCF-SDC hollow fiber membranes are limited by surface exchange reactions. LSCF-SDC hollow fiber membranes also demonstrated high resistance to CO2 in short-term stability test.

Optomechanical assessment of photorefractive corneal cross-linking via optical coherence elastography.

Purpose: Corneal cross-linking (CXL) has recently been used with promising results to positively affect corneal refractive power in the treatment of hyperopia and mild myopia. However, understanding and predicting the optomechanical changes induced by this procedure are challenging. Methods: We applied ambient pressure modulation based optical coherence elastography (OCE) to quantify the refractive and mechanical effects of patterned CXL and their relationship to energy delivered during the treatment on porcine corneas. Three different patterned treatments were performed, designed according to Zernike polynomial functions (circle, astigmatism, coma). In addition, three different irradiation protocols were analyzed: standard Dresden CXL (fluence of 5.4J/cm2), accelerated CXL (fluence of 5.4J/cm2), and high-fluence CXL (fluence of 16.2J/cm2). The axial strain distribution in the stroma induced by ocular inflation (Δp = 30mmHg) was quantified, maps of the anterior sagittal curvature were constructed and cylindrical refraction was assessed. Results: Thirty minutes after CXL, there was a statistically significant increase in axial strain amplitude (p < 0.050) and a reduction in sagittal curvature (p < 0.050) in the regions treated with all irradiation patterns compared to the non-irradiated ones. Thirty-6hours later, the non-irradiated regions showed compressive strains, while the axial strain in the CXL-treated regions was close to zero, and the reduction in sagittal curvature observed 30minutes after the treatment was maintained. The Dresden CXL and accelerated CXL produced comparable amounts of stiffening and refractive changes (p = 0.856), while high-fluence CXL produced the strongest response in terms of axial strain (6.9‰ ± 1.9‰) and refractive correction (3.4 ± 0.9 D). Tripling the energy administered during CXL resulted in a 2.4-fold increase in the resulting refractive correction. Conclusion: OCE showed that refractive changes and alterations in corneal biomechanics are directly related. A patient-specific selection of both, the administered UV fluence and the irradiation pattern during CXL is promising to allow customized photorefractive corrections in the future.

Synchronous pressure-induced enhancement in the photoresponsivity and response speed of BiOBr

The development of the optoelectronics industry relies on the constant exploration and improvement of the photoelectric properties of functional materials. Responsivity and response speed are two key performance indicators of photodetectors. However, these parameters are often mutually suppressed, and ensuring both simultaneously is challenging. Herein, we developed a viable strategy to enhance the overall photodetection performance by applying pressure to improve both the photoresponsivity and the response speed of BiOBr simultaneously. The results showed that the responsivity of BiOBr at a pressure of 3.8 GPa was more than an order of magnitude higher than that measured at the initial pressure (0.2 GPa) under Xenon-light illumination. More importantly, the response speed of BiOBr was improved by almost an order of magnitude under 3.7 GPa and 405 nm laser illumination. The considerably enhanced photoresponsivity and photoresponse speed suggest that pressure effectively reduces the effective mass of carriers and promotes charge transfer between Bi-O atoms. Our findings reveal that comprehensive enhancement of optoelectronic properties in layered compounds can be achieved through pressure modulation of the electronic structure, providing a promising approach for materials design toward extraordinary properties.

Electrical stimulation of the ventromedial prefrontal cortex modulates muscle sympathetic nerve activity and blood pressure.

We recently showed that transcranial alternating current stimulation of the dorsolateral prefrontal cortex modulates spontaneous bursts of muscle sympathetic nerve activity, heart rate, and blood pressure (Sesa-Ashton G, Wong R, McCarthy B, Datta S, Henderson LA, Dawood T, Macefield VG. Stimulation of the dorsolateral prefrontal cortex modulates muscle sympathetic nerve activity and blood pressure in humans. Cereb Cortex Comm. 2022:3:2tgac017.). Stimulation was delivered between scalp electrodes placed over the nasion and electroencephalogram (EEG) electrode site F3 (left dorsolateral prefrontal cortex) or F4 (right dorsolateral prefrontal cortex), and therefore the current passed within the anatomical locations underlying the left and right ventromedial prefrontal cortices. Accordingly, we tested the hypothesis that stimulation of the left and right ventromedial prefrontal cortices would also modulate muscle sympathetic nerve activity, although we predicted that this would be weaker than that seen during dorsolateral prefrontal cortex stimulation. We further tested whether stimulation of the right ventromedial prefrontal cortices would cause greater modulation of muscle sympathetic nerve activity, than stimulation of the left ventromedial prefrontal cortices. In 11 individuals, muscle sympathetic nerve activity was recorded via microelectrodes inserted into the right common peroneal nerve, together with continuous blood pressure, electrocardiogram, and respiration. Stimulation was achieved using transcranial alternating current stimulation, +2 to -2mA, 0.08Hz, 100cycles, applied between electrodes placed over the nasion, and EEG electrode site FP1, (left ventromedial prefrontal cortices) or FP2 (right ventromedial prefrontal cortices); for comparison, stimulation was also applied over F4 (right dorsolateral prefrontal cortex). Stimulation of all three cortical sites caused partial entrainment of muscle sympathetic nerve activity to the sinusoidal stimulation, together with modulation of blood pressure and heart rate. We found a significant fall in mean blood pressure of ~6mmHg (P = 0.039) during stimulation of the left ventromedial prefrontal cortices, as compared with stimulation of the right. We have shown, for the first time, that transcranial alternating current stimulation of the ventromedial prefrontal cortices modulates muscle sympathetic nerve activity and blood pressure in awake humans at rest. However, it is unclear if this modulation occurred through the same brain pathways activated during transcranial alternating current stimulation of the dorsolateral prefrontal cortex.

Economical Configuration of Oxygen-Enriched Air Production Process Using Polysulfone-Based Composite Membranes

Oxygen-enriched combustion technology is an emerging incineration method suitable for waste treatment. In this study, we investigated an economical modular configuration method for oxygen-enriched air production using gas separation membrane technology. Various module configurations were examined based on input pressure, gas temperature, sweep, and multistage module arrangement, and an optimal economically viable configuration was proposed. Using a polysulfone-based polymer membrane module, oxygen-enriched air with an oxygen concentration of 40–65% was produced. Even in cases of low input pressures achieved using a vacuum pump at the permeate side, oxygen-enriched air with concentrations &gt;40% was achieved, with an approximately 20% increase in the permeation flow rate. As the permeation rate increased with increasing temperature, the oxygen recovery efficiency decreased. When the membrane area was increased, the corresponding increase in the input pressure did not result in a proportional increase in the permeation rate compared with single-module setups. Through multistage module arrangements, oxygen-enriched air with a maximum oxygen concentration of 66% was produced. By employing sweep that recirculated a portion of input air to the permeate side, the production of oxygen-enriched air was enhanced by approximately 38%. Therefore, the proposed process involving low input pressure, vacuum pumps, and sweeping was optimal for oxygen-enriched air production.

Abstract 201: 3D-Printed Automated Pressure-Cycled Resuscitator Maintains Respiratory Homeostasis in Swine With Normal to Moderately Low Lung Compliance

Background: During resuscitation, manual ventilation is commonly used. However, the effectiveness of this approach heavily relies on the skills of the individuals performing, often leading to inconsistent tidal volumes and respiratory rates. Such variations in ventilation can disrupt the removal of CO 2 resulting in altered pH. To address this problem, we leveraged advancements in fluidics and 3D printing to develop a miniature, automated, pressure-cycled resuscitator (inVent) that operates without any moving parts or settings. Hypothesis: The inVent will be able to maintain a pH of 7.2 or higher in swine with a dynamic compliance (Cdyn) of 25-50 ml/cmH 2 O. Goals/Aims: To assess the inVent’s performance in an animal model with normal to severe lung injury. Methods: Hybrid Landrace swine were studied under a protocol approved by the Institutional Animal Care and Use Committee. All swine were anesthetized, and underwent oral intubation. Breath by breath measurements were obtained using the NM3 Monitor (Phillips). All 3 inVent (fluidIQ) resuscitators pressure modules were used pre and post lung injury to fully characterize how each of the modules would react in different lung conditions. Lung injury was induced through a repeated bronchoalveolar lavage. ABG analysis was performed using the epoc system (Siemens). pH values 7.2 or less were considered acidotic while those over 7.2 were considered acceptable. Results: 8 swine with an average weight of 36 (5.8) Kg were studied. 7 swine contributed to 39,770 breaths of pulmonary mechanics and 33 ABGs recorded. Mean Cdyn was lower than anticipated at 25.8 (14.7) mL/cmH 2 O and a pH 7.32 (0.16). Figure 1 demonstrates a linear relationship with compliance and pH. Conclusions: The inVent resuscitator was able to maintain a pH of at least 7.2 in moderate compliance ranges, however struggled to maintain pH of 7.2 or higher in the severely injured. Higher lung compliance ranges are needed to explore possible hyperventilation events.

Development of last stage blade of 13K215 turbine intermediate pressure module

Development of last stage blade of 13K215 turbine intermediate pressure module

Genetic diversity and natural selection of apical membrane antigen-1 (ama-1) in Cameroonian Plasmodium falciparum isolates

Antigenic variation associated with genetic diversity in global Plasmodium falciparum apical membrane antigen-1 (PfAMA-1) is a major impediment to designing an effective malaria vaccine. Here, we report the first study on genetic diversity and natural selection of the Pfama-1 gene in P. falciparum isolates from Cameroon. A total of 328 P. falciparum positive samples collected during 2016 and 2019 from five localities of Cameroon were analysed. The ectodomain coding fragment of Pfama-1 gene was amplified for polymorphism profiling and natural selection analysis. A total of 108 distinct haplotypes were found in 203 P. falciparum isolates with considerable nucleotide diversity (π = 0.016) and haplotype diversity (Hd = 0.976). Most amino acid substitutions detected were scattered in ectodomain-I and few specific mutations viz P145L, K148Q, K462I, L463F, N471K, S482L, E537G, K546R and I547F were seen only in Cameroonian isolates. A tendency of natural selection towards positive diversifying selection was observed (Taj-D = 2.058). Five positively selected codon sites (P145L, S283L, Q308E/K, P330S and I547F) were identified, which overlapped with predicted B-cell epitopes and red blood cell (RBC) binding sites, suggesting their potential implication in host immune pressure and parasite-RBC binding complex modulation. The Cameroonian P. falciparum populations indicated a moderate level of genetic differentiation when compared with global sequences, with few exceptions from Vietnam and Venezuela. Our findings provide baseline data on existing Pfama-1 gene polymorphisms in Cameroonian field isolates, which will be useful information for malaria vaccine design.

Electron beam irradiation modification of ultra-high pressure treated broad bean starch: Improvement of multi-scale structure and functional properties.

To investigate the synergistic effect of electron beam irradiation (EBI) on the ultra-high pressure (UHP) modification of broad bean starch, various pressures (200, 400, 600MPa) combined with different irradiation doses (3, 6, 12kGy) were used to modify the structure-properties of broad bean starch in this study. The results showed that both UHP and EBI induced a reduction of amylopectin molecular weight (Mw) and depolymerization of long chains, caused the loss of short-range ordered structure and imperfection of crystal structure, and improved starch viscosity, solubility and enzyme sensitivity. Furthermore, the applied pressure causes changes in starch granule structure, upon which EBI promotes further degradation and depolymerization of starch by affecting the crystalline and amorphous regions. Hence, appropriate doses of EBI treatment can impart more desirable processing properties to UHP-modified starches, and EBI can be used as a promising way to promote starch modification further.

Association of activin A and postpartum blood pressure in peripartum cardiomyopathy

BackgroundActivin A has been implicated in the pathogenesis of patients with chronic hypertension and heart failure as well as patients with hypertensive disorders of pregnancy (HDP). Whether activin A correlates with blood pressure in patients with peripartum cardiomyopathy (PPCM) and HDP history has not previously been explored. Methods and results82 women with PPCM w/ and w/out HDP or hypertension history were selected for analysis from the Investigations in Pregnancy Associated Cardiomyopathy (IPAC) study. Serum biomarkers and blood pressure were assessed at the time of enrollment (median postpartum day 24). Levels of both sFlt-1 (SBP: r 0.47, p = 0.008; DBP: r 0.57, p < 0.001) and activin A (SBP: r 0.59, p < 0.001;DBP: r 0.68, p < 0.001) were noted to significantly correlate with blood pressure in patients with a history of HDP who went on to develop PPCM, but not in patients with chronic hypertension or no hypertensive history. The strongest correlation was between activin A levels and postpartum diastolic blood pressure for the subset with preeclampsia (DBP: r0.82, p < 0.001). This remained significant in multivariable linear regression analysis (DBP: β = 0.011, p = 0.015). ConclusionIn patients with PPCM, activin A and sFlt-1 levels had direct correlations with both systolic (SBP) and diastolic blood pressures (DBP), but only in participants with history of HDP. This correlation was more evident for activin A and strongest with a history of preeclampsia. Our findings suggest that activin A may play an important role in blood pressure modulation in women with HDP who subsequently develop PPCM.

Enhancing cord blood stem cell-derived NK cell growth and differentiation through hyperosmosis

BackgroundNatural killer (NK) cells hold great promise in treating diverse hematopoietic and solid tumors. Despite their availability from peripheral blood and cord blood, stem cell-derived NK cells offer an 'off-the-shelf' solution. Hematopoietic stem and progenitor cells (HSPCs) derived from cord blood pose no risk to the newborn or mother and are virtually ideal sources for NK cell differentiation.MethodsWe developed a modified protocol to differentiate HSPCs to NK cells under serum-free conditions using defined factors. The HSPC-derived NK (HSC-NK) cells could be expanded in a K562 feeder cell-dependent manner. Furthermore, using lentivirus transduction, chimeric antigen receptor (CAR)-modified HSPCs could be differentiated into NK cells, leading to the establishment of CAR-NK cells.ResultsThe efficiency of NK cell differentiation from HSPCs was increased through the simple modulation of osmotic pressure by the addition of sodium chloride or glucose. Furthermore, the hyperosmosis-primed HSC-NK cells exhibited enhanced proliferation capacity and maintained normal functional characteristics, including transcriptome and antitumor efficacy. The optimized protocol yielded approximately 1.8 million NK cells from a single CD34-positive cell within a 28-day cycle, which signifies more than a ten-fold increase in efficiency relative to the conventional methods. This optimized protocol was also suitable for generating CAR-NK cells with high yields compared to standard conditions.ConclusionsThe results of this study establish high osmotic pressure as a simple yet powerful adjustment that significantly enhances the efficiency and functionality of HSC-NK cells, including CAR-NK cells. This optimized protocol could lead to cost-effective, high-yield NK cell therapies, potentially revolutionizing cancer immunotherapy strategies.

Enhanced carrier mobility in MoSe2 by pressure modulation

Enhanced carrier mobility in MoSe2 by pressure modulation