Pressure Difference Research Articles

Kinetic study of the reaction of thiophene-tocopherols with peroxyl radicals enlightenings the role of O˙⋯S noncovalent interactions in H-atom transfer.

Three new α-tocopherol thiophene derivatives were efficiently synthesized, characterized and used for the first time as chain-breaking antioxidants for the inhibition of the autoxidation of reference oxidizable substrates. The rate constant of the reaction with alkylperoxyl (ROO˙) radicals and the stoichiometry of radical trapping (n) for the thiophene-tocopherol compounds were determined by measuring the oxygen consumption during the autoxidation of styrene or isopropylbenzene, using a differential pressure transducer. The measurement of the reaction with ROO˙ radicals in an apolar solvent at 30 °C showed inhibition rate constants (kinh) in the order of 104 M-1 s-1. To rationalise the kinetic results, the effect of the thiophene ring on the H-atom donation by O-H groups of the functionalized tocopherols was investigated by theoretical calculations. The importance of noncovalent interactions (including an unusual O˙⋯S bond) for the stability of the conformers has been shown, and the O-H bond dissociation enthalpy (BDE(OH)) of these derivatives was determined. Finally, the photophysical properties of these new compounds were investigated to understand if the addition of thiophene groups changes the absorption or emission spectra of the tocopherol skeleton for their possible application as luminescent molecular probes.

Measurement of Air-Water Counter-Current Flow Rates in Vertical Annulus Using Multiple Differential Pressure Signals and Machine Learning

Measurement of Air-Water Counter-Current Flow Rates in Vertical Annulus Using Multiple Differential Pressure Signals and Machine Learning

Mixed convective flow analysis of a Maxwell fluid with double diffusion theory on a vertically exponentially stretching surface

It observers that an object is submerged in a liquid, more pressure is applied to its bottom surface than its top surface, as a result pressure rises within depth of fluids. A buoyancy force is generated due to the pressure difference. In the current investigation, the mathematical formulation of bio-convective stagnation point flow of a radiative Maxwell fluid with multiple slip effect on an exponentially porous stretching surface is analyzed thoroughly. The buoyancy assisting and opposing conditions with magnetic field are discussed in the current investigation. Moreover, the energy and concertation equations are formulated by the utilization of Cattaneo–Christov theory and non-uniform heat source/sink. The flow model is developed in the form of partial derivatives, then use the similarity variables to convert the physical system into nonlinear ordinary derivative. The nonlinear system is tackled numerically with the help of Bvp4c approach on the MATLAB. The graphical upshots for various emerging parameter are observed with two aspects: buoyancy assisting λ>0\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\left( {\\lambda > 0} \\right)$$\\end{document} and buoyancy opposing λ<0\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\left( {\\lambda < 0} \\right)$$\\end{document}. The observation shows that the greater values of mixed convection parameter improves the fluid velocity for assisting flow λ>0\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\left( {\\lambda > 0} \\right)$$\\end{document}, while declining trend is noticing for opposing flow situation λ>0\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\left( {\\lambda > 0} \\right)$$\\end{document}. Further, it is worth noticing that stronger inputs of thermal and concentration relaxation parameter yield lesser thermal and concentration diffusivity, which reduces the temperature and nanoparticles concentration.

Association between early pregnancy maternal blood pressure and risk of congenital heart disease in offspring

Objective: To analyze the association between maternal blood pressure and congenital heart disease (CHD) in offspring. Methods: From February 2018 to December 2020, pregnant women who participated in the China birth cohort study in Beijing Obstetrics and Gynecology Hospital, Shenzhen Maternal and Child Healthcare Hospital and Chengdu Women's and Children's Central Hospital were enrolled in this study. The baseline and follow-up information were collected using an electronic data collection system. Stepwise logistic regression model was used to analyze the association between maternal blood pressure including systolic blood pressure (SBP), diastolic blood pressure (DBP), mean arterial pressure (MAP) and pulse pressure difference (PP) in the first trimester of pregnancy and the risk of CHD in the offspring. A restrictive cubic spline curve was used to draw the dose-response curve between maternal blood pressure and CHD. Results: A total of 55 552 participants were included in this study. Of them, 31 038, 15 375 and 9 139 pregnant women were enrolled in Beijing Obstetrics and Gynecology Hospital, Shenzhen Maternal & Child Healthcare Hospital and Chendu Women's and Children's Central Hospital, respecitively. The age of pregnant women was (31.3±4.0) and the incidence of CHD in the offspring was 0.78% (435/55 552). Multivariable logistic regression model analysis showed that the increase of SBP (OR=1.01, 95%CI: 1.00-1.02), DBP (OR=1.01, 95%CI: 1.00-1.03) and MAP (OR=1.02, 95%CI: 1.00-1.03) in the first trimester were significantly associated with the risk of CHD in the offspring. The restrictive cubic spline analysis showed a positive linear association of SBP (Ptotal<0.001; Pnon-liear=0.315), DBP (Ptotal<0.001; Pnon-liear=0.928) and MAP (Ptotal<0.001; Pnon-liear=0.929) with the risk of CHD in the offspring. Conclusion: Maternal SBP, DBP and MAP in the first trimester of pregnancy were positively associated with the risk of CHD in the offspring.

Effect of Fentanyl Compared to Morphine on Pain Score and Cardiorespiratory Vital Signs in Out-of-Hospital Adult STEMI Patients

Objective: ST-elevation myocardial infarction (STEMI) is a leading cause of mortality in Australia. Paramedics treating adults with STEMI in the out-of-hospital environment can use fentanyl or morphine to manage the patient’s pain, although there is little research comparing the efficacy and safety of these drugs. Therefore, the objective of this study was to compare the effects of fentanyl to morphine on cardiac chest pain and cardiorespiratory vital signs in adult STEMI patients in the out-of-hospital environment. Methods: We conducted a retrospective analysis of records of 1902 STEMI cases attended by Queensland Ambulance Service paramedics during the 4-year interval from 2013 to 2016. We compared pain score, blood pressure, respiratory rate, and pulse rate between patients administered intravenous fentanyl and intravenous morphine. We used a two-way mixed effects model (drug, time) to assess for main and interaction effects, and where the interaction effect was significant, applied Mann-Whitney U tests to further analyze between-group differences at each time point. Results: We observed a significant main effect of time on pain score (p &lt; 0.001), respiratory rate (p &lt; 0.05), and pulse rate (p = 0.025), such that these variables all decreased over time. Additionally, we observed a significant drug-time interaction for systolic and diastolic blood pressures (both p &lt; 0.01), such that blood pressures decreased over time in the morphine, but not fentanyl, group. Conclusion: We compared the effects of fentanyl to morphine on cardiac chest pain and cardiorespiratory vital signs in out-of-hospital adult STEMI patients and observed differences in blood pressures only. Morphine appeared to have a depressive effect on systolic and diastolic blood pressure, whereas fentanyl did not. An unanticipated behavioural finding of this research is that, in the absence of a definitive guideline, paramedics appear to use fentanyl when patients may be at risk of developing hypotension.

Inertia from radiation. A semiclassical approach

Abstract Starting from a thought experiment based on an accelerated reflecting cavity that contains a radiation bath, is evaluated the cavity-radiation dynamical interaction. The radiation is considered as a monochromatic flux of photons that bouncing onward and backward in the direction of acceleration. For this case, in each reflection, the delay originated by the time of flight of photons causes a difference of velocity between the receiving and emitting reflecting faces in the opposite ends of cavity, and consequently, a Doppler shift. Despite to the ends of the cavity are at rest relative to each other, this phenomenon generates a difference of radiation pressure between these, that behave as the inertia of the radiation bath and verifies the Newton’s 2nd Law for non-relativistic conditions. This result has interesting implications on the current theoretical pictures of dynamical properties of photons.

Design and dynamic characterization of a phototunable optofluidic lens

Optofluidic devices that dynamically respond to light stimuli have the potential to impart modern adaptive optics with intrinsic optical logic without the need for external power sources or feedback control. While photo actuation is typically associated with low energy efficiency compared with alternative modes of actuation, fluid lenses can be tuned with minimal work by generating small differential pressures across the surface of the lens to drive a change in focal length. In this study, we developed a wide aperture (9.5 mm) photothermally actuated lens that leverages spatially and thermodynamically informed design principles developed for resistively heated thermo-pneumatically actuated lenses. Using experimentally validated models to describe the curvature of pressurized elastomer-bound interfaces, we demonstrated phototunable modulation of the focal length from 124 mm to 90 mm in real time using 233 mW of 405 nm light over 30 s of irradiation with an estimated 8.2 µJ of mechanical work (10−4% efficiency). The initial focal length recovered after 60 s in the dark over three consecutive cycles of actuation. Additionally, the photoactuated response is shown to correlate well with the light intensity.

Multi-Objective Optimization Design of Dynamic Performance of Hydrofoil with Gurney Flap

The horizontal axis tidal turbine, as a crucial device for capturing tidal energy, has gained significant attention because it has better energy efficiency performance. Enhancing the performance of foils, a vital part of tidal turbine blades, can significantly improve tidal turbine performance. Among numerous methods to enhance the foil performance, the Gurney flap has gained significant attention due to its avoidance of complex structural design. Currently, there is limited research on optimizing the design of Gurney flaps while considering the dynamic performance of foils. In this study, the S809 foil with a blade cross-section was selected as the research subject, a multi-objective optimization design platform was created by integrating a multi-objective optimization algorithm with Computational Fluid Dy-namics (CFD) numerical simulation techniques. The objective of this platform is to enhance the dynamic performance of the hydrofoil by optimizing the geometric structure of the Gurney flap. The improvement of dynamic lift and the size of the dynamic stall hysteresis loop are used as objective variables in this study to evaluate the hydrofoil’s dynamic performance. The optimal Latin hypercube design method is used in the optimization process to choose sample locations, and the Kriging approximation model is used to determine the relationship between the design variables and the objective variables. Meanwhile, the Non-Dominated Sorting Genetic Algorithm-II (NSGA-II) is used to create a multi-objective optimization platform for solving the optimization problem, and the optimized results are validated using CFD. Comparative validation results show that quantifying the dynamic performance during hydrofoil pitching oscillation and using the optimal Latin hypercube design method and Kriging approximation model for optimizing the Gurney flap structure is rational and accurate. This study explores the mechanism of the Gurney flap through in-depth CFD numerical simulations and finds that the Gurney flap affects the flow characteristics at the hydrofoil’s trailing edge, thereby influencing the performance. It increases the pressure difference between the pressure and suction surfaces, thus enhancing the hydrofoil’s lift. Finally, this article provides three recommended parameters to improve the dynamic performance of the hydrofoil. This research can serve as a reference for the application of Gurney flaps in tidal turbine blade design.

Vortex safety when flying at an assigned flight level

Air traffic intensity between countries and within individual countries is increasing year by year. As a rule, airways follow the same routes. As a result, so-called “roads in the sky” are formed. And where there are roads, there are bumps by the time, in the form of CAT, updraughts and downdraughts and increased turbulence. Horizontal and vertical separation plays an important role in ensuring flight safety on route. Currently, a variety of regulatory documents, defining safe separation at the flight level, has been adopted. Thus, provided there is turbulence in the vortex wake, longitudinal separation is based on the arrangement of aircraft types by three categories according to their maximum certified take-off weight. Since November 2011, the Western standard of vertical separation RVSM (Reduced Vertical Separation Minimum) has been introduced in Russia. Vertical separation is the distance between the vertical flight levels on route. Previously, this distance amounted to 600 m (2000 ft), but due to the increasing intensity of air traffic, it was decided to reduce the vertical separation to 300 m (1000 ft). Hence, at the most common flight level, the vertical separation is 300 m. The question arises if this separation ensures the safety of air transportation? The fact is that the altitude of the flight level does not necessarily coincide with the actual aircraft height. Aircraft altimeters are, inherently, calibrated barometers, that calculate the altitude by the difference in pressure on the ground and in the air. To calculate the height above ground, it would be necessary to constantly input atmospheric pressure data to altimeters at each waypoint and take into consideration the waypoint altitude above the sea level. Consequently, it is customary to use standard pressure. If the same pressure values are set on the altimeter on all aircraft, then, altitude readings on the instrument at an assigned point of airspace will be similar. Therefore, from a certain moment during the climb (transition level) to a certain moment during the descent (transition level), the aircraft height is calculated according to the standard pressure. The value of the standard pressure (QNE) is the same all over the world and amounts to 760 mmHg (1013.2 hectopascals). Thus, the flight on route is controlled by an altimeter, a barometric altimeter, which is comprised into the integrated flight and navigation system. An analysis of the instrument accuracy shows that when atmospheric pressure drops, altimeter readings may differ from true reading by ±100 m. It is known that a trailing vortex forms behind a flying plane. By the time, the trailing vortex descends and may be found at another flight level. May this cause air bump at the flight level? To answer this question, the A-380 aircraft was chosen as the object of research. This is one of the largest aircraft in the world. Therefore, the study of a trailing vortex behind the A-380 at the flight level, as the most dangerous in terms of the impact of its trailing vortex on other aircraft, will allow us to understand how safe and reasonable the accepted vertical and horizontal separation is. For the study, the special computational software system, based on the discrete vortex method, was used. This complex has passed the evaluation test and the state registration.

Diagnostic value of reversed differential cyanosis in (supra)cardiac total anomalous pulmonary venous return.

To investigate the occurrence of reversed differential cyanosis (RDC) in case of (supra)cardiac total anomalous pulmonary venous return (TAPVR), we explored the hemodynamic changes and oxygen saturation levels during the fetal-to-neonatal transition in (supra)cardiac TAPVR, thereby revealing determinant factors of RDC. A computational model was used to simulate the cardiovascular fetal-to-neonatal transition up to 24 h after birth. Abnormalities associated with TAPVR, like patent ductus arteriosus (PDA) and persistent pulmonary hypertension of the neonate (PPHN), were imposed on the model. Hemodynamic impact on flow distribution and right-sided pressures as well as oxygen saturations were assessed. Model findings demonstrated that RDC in (supra)cardiac TAPVR was dependent on two key factors: (1) the type of pulmonary venous connection being supracardiac or cardiac, and (2) the presence of a patent ductus arteriosus exhibiting right-to-left shunting. Persistence of RDC was mainly determined by the latter; an increase in pulmonary-to-systemic pressure difference by PPHN or PDA-induced pulmonary over-circulation contributed to persistence of RDC. This study highlights the significance of RDC in (supra)cardiac TAPVR and suggests to incorporate early screening ( < 24 h after birth) and to consider RDC as an immediate fail in screening protocols to ensure prompt detection of (supra)cardiac TAPVR. Utilizing a validated computational model for the cardiovascular fetal-to-neonatal transition, this study sheds light on the complex hemodynamics in neonates with (supra)cardiac Total Anomalous Pulmonary Venous Return (TAPVR). Model findings suggest that the often-present pulmonary over-circulation in neonates with TAPVR might significantly contribute to the anomaly's frequent omission during pulse-oximetry screening beyond the first 24 h after birth. This study highlights the diagnostic value of reversed differential cyanosis in early screenings within the first 24 h after birth. By including RDC as an immediate fail in early pulse-oximetry screenings, the likelihood of missing (supra)cardiac TAPVR cases could be reduced.

Sundowner Winds at Montecito during the Sundowner Winds Experiment

This study investigates the predictability of downslope windstorms located in Santa Barbara County, California, locally referred to as Sundowner winds, from both observed relationships and a high-resolution, operational numerical weather prediction model. We focus on April 2022, during which the Sundowner Winds Experiment (SWEX) was conducted. We further refine our study area to the Montecito region owing to some of the highest wind measurements occurring at or near surface station MTIC1, situated on the coast-facing slope overlooking the area. Fires are not uncommon in this area, and the difficulty of egress makes the population particularly vulnerable. Area forecasters often use the sea-level pressure difference (ΔSLP) between Santa Barbara Airport (KSBA) and locations to the north such as Bakersfield (KBFL) to predict Sundowner windstorm occurrence. Our analysis indicates that ΔSLP by itself is prone to high false alarm rates and offers little information regarding downslope wind onset, duration, or magnitude. Additionally, our analysis shows that the high-resolution rapid refresh (HRRR) model has limited predictive skill overall for forecasting winds in the Montecito area. The HRRR, however, skillfully predicts KSBA-KBFL ΔSLP, as does GraphCast, a machine learning weather prediction model. Using a logistic regression model we were able to predict the occurrence of winds exceeding 9 m s−1 with a high probability of detection while minimizing false alarm rates compared to other methods analyzed. This provides a refined and easily computed algorithm for operational applications.

Importance of Fluid/Fluid Interactions in Enhancing Oil Recovery by Optimizing Low-Salinity Waterflooding in Sandstones

Low-salinity waterflooding/smart waterflooding (LSWF/SWF) is a technique involving the injection of water with a modified composition to alter the equilibrium between rock and fluids within porous media to enhance oil recovery. This approach offers significant advantages, including environmental friendliness and economic efficiency. Rock/fluid mechanisms such as wettability alteration and fines migration and fluid/fluid mechanisms such as a change in interfacial tension and viscoelasticity are considered active mechanisms during LSWF/SWF. In this study, we evaluated the effect of these mechanisms, by LSWF/SWF, on sandstones. To investigate the dominant mechanisms, coreflooding studies were performed using different injected fluid composition/salinity and wettability states. A comparative analysis of the recovery and mobility reduction factor was performed to clarify the conditions at which fluid/fluid mechanisms are also effective. Our studies showed that wettability alteration is the most dominant mechanism during LSWF/SWF, but, for weak oil-wet cases, optimizing brine compositions may activate fluid/fluid mechanisms. Brine composition significantly influences interface stability and performance, with sulfate content playing a crucial role in enhancing interface properties. This was observed via mobility behavior. A comparative analysis of pressure differentials showed that fines migration may act as a secondary mechanism and not a dominant one. This study highlights the importance of tailored brine compositions in maximizing oil recovery and emphasizes the complex interplay between rock and fluid properties in enhanced oil recovery strategies.

Interfacial exchange of airflow and bacteria-carrying particles induced by door opening and foot traffic in an operating room

Maintaining high air cleanliness in operating rooms (ORs) can reduce surgical site infections (SSIs). However, door openings and foot traffic during surgery may allow the intrusion of contaminated air and increase microbial contamination in ORs. In this study, numerical methods were applied to investigate the dynamic airflow and bacteria-carrying particle (BCP) dispersion during sliding door opening and foot traffic in an OR. The door movement and realistic human walking were modeled by the dynamic mesh technique. The interfacial exchange of airflow and BCPs was evaluated as the medical staff entered and exited the OR under fixed supply air temperatures and various differential pressures, respectively. Results showed that walking across the door interface caused a sharp increase in airflow exchange between the OR and the anteroom (ANT). An average walking speed of 1.2 m/s induced a maximum inflow rate of approximately 1.32 times greater when entering the OR than when leaving the OR. Once the door was open, the temperature difference convection effect was more significant than the pressure difference outflow effect. Differential pressure outflow indirectly affected airflow exchange at the door interface by changing the direction and temperature of airflow in the ANT. Whether entering or leaving the OR, the BCP intrusion ratios were on average 1.5 times higher at high pressure differentials (15 and 20 Pa) than at low pressure differentials (5 Pa and 10 Pa). This study is expected to improve the understanding of the impact of door opening and foot traffic on OR air quality during surgery.

Correlation between oral muscle pressure and malocclusion in mixed dentition: a cross-sectional study.

To investigate the relationship between oral muscle pressure and malocclusion in the mixed dentition. Maximum tongue, lip and cheek pressure was measured using the Iowa Oral Performance Instrument (IOPI) in 3 patient cohorts: patients with (1) posterior crossbite, (2) class II relationship and (3) a control group of patients without malocclusion. Linear models were used to compare the mean differences in muscle pressure between groups, with correction for age and gender. The imbalance between lips and tongue and between lips and cheeks was calculated by the Delta z-scores of each group. A total of 146 participants were included, 46 (mean age 8.71±0.85), 41 (mean age 11.74±1.17) and 35 (mean age 10.71±1.92) in groups 1, 2 and 3 respectively. Patients with malocclusion showed significantly higher lip and lower cheek pressure and imbalance favouring the lips over the tongue compared to controls. Class II,1 patients showed significantly higher tongue pressure than Class II,2. No differences were found in muscle pressure or imbalance between crossbite and Class II nor between crossbite types. These findings suggest that oral muscle pressure may be associated with malocclusion. This highlights the importance of functional diagnosis and its implications on the prevention and treatment of malocclusion, as well as on orthodontic stability.

New insight into enhanced carbon recovery from anaerobic fermentation of waste activated sludge with cation exchange resin coupled with NaCl pretreatment

Carbon recovery from waste activated sludge has been attracting considerable attention. However, the migration and transformation patterns of carbon sources between the phases have rarely been reported. In this study, a novel strategy using cation exchange resin (CER) coupled with sodium chloride (NaCl) to enhance carbon recovery through anaerobic fermentation (AF) was proposed. The results demonstrated that CER coupled with NaCl destroyed OH and CO stretching in amide I while promoting the formation of β-sheet and random coil structures, leading to sludge disintegration. This significantly improved the kinetics of endogenous carbon release, resulting in the release of 1146.33 mg/L of carbon from the solid sludge into the liquid phase. Approximately 75.61 % of the initial carbon source was bio-transformed into short-chain fatty acids. Correspondingly, carbon recovery was significantly increased up to 852.23 mg C/L, 4.57 times that of the control. Mechanism exploration revealed that carbon source recovery was significantly elevated by the synergistic effect of CER and NaCl. CER effectively removed high-valence cations from extracellular polymeric substance (EPS), weakening its bridging and adsorption-electro neutralization capabilities, promoting protein deflocculation, and triggering EPS disruption to release extracellular carbon sources. NaCl disrupted the ionic strength and distribution inside and outside microbial cells, creating an osmotic pressure difference that resulted in cell plasmolysis and lysis, ultimately inducing the release of intracellular carbon sources. Economic and carbon emission reduction benefit analyses verified that the CER coupled with NaCl pretreatment is a cost-effective sludge treatment strategy. This study illustrates the carbon source migration and transformation pathways in the CER coupled with NaCl-assisted AF process, providing guidance for sustainable sludge management.

COMPUTATIONAL AND EXPERIMENTAL STUDY OF THE STRESS-STRAIN STATE OF A PIPE UNDER EXTERNAL RADIAL LOAD, INTERNAL PRESSURE AND TEMPERATURE DIFFERENCE

Oil and gas pipelines are subjected to complex of loads and impacts during operation. The purpose of this article is an experimental assessment of the stress-strain state of a pipe under the action of external radial force on a laboratory bench by the strain gauge method, as well as a computational and experimental assessment of the stress-strain state under the combined action of radial force, internal pressure and temperature difference. Accounting for internal pressure and temperature difference (other factors affecting the pipeline) is carried out using well-known theoretical formulas which are confirmed by practice. The total stresses from the effects of several factors of influence are determined due to the principle of superposition.Experimental and computational studies of the stress-strain state of the pipe cross section under the influence of external radial force corresponding to the pipe deflection from 0 to 8 mm; internal pressure from 0 to 14 MPa; temperature difference from minus 60 C to 60 C have been carried out. Graphs of the dependence of maximum stresses on the factors of influence are constructed. Empirical formulas have been obtained for calculating the maximum equivalent von Mises stress of the cross-section of the pipe with a diameter of 325 mm under various loading options, they are necessary to assess the strength of the pipeline structure.

Prospective validation of a mobile health application for blood pressure management in patients with hypertensive disorders of pregnancy: study protocol for a randomized controlled trial

BackgroundHypertensive disorders of pregnancy (HDP) pose significant risks to both maternal and fetal health, contributing to global morbidity and mortality. Management of HDP is complex, particularly because of concerns regarding potential negative effects on utero-placental circulation and limited therapeutic options due to fetal safety. Our study investigates whether blood pressure monitoring through a mobile health (mHealth) application can aid in addressing the challenges of blood pressure management in pregnant individuals with HDP. Additionally, we aim to assess whether this intervention can improve short-term maternal and fetal outcomes and potentially mitigate long-term cardiovascular consequences.MethodsThis prospective, randomized, single-center trial will include 580 pregnant participants who meet the HDP criteria or who have a heightened risk of pregnancy-related hypertension due to factors such as multiple pregnancies, obesity, diabetes, or a history of HDP in prior pregnancies leading to preterm birth. Participants will be randomized to either the mHealth intervention group or the standard care group. The primary endpoint is the difference in systolic blood pressure from enrollment to 1 month after childbirth. The secondary endpoints include various blood pressure parameters, obstetric outcomes, body mass index trajectory, step counts, mood assessment, and drug adherence.ConclusionsThis study emphasizes the potential of mHealth interventions, such as the Heart4U application, to improve blood pressure management in pregnant individuals with HDP. By leveraging technology to enhance engagement, communication, and monitoring, this study aims to positively impact maternal, fetal, and postpartum outcomes associated with HDP. This innovative approach demonstrates the potential of personalized technology-driven solutions for managing complex health conditions.Trial registrationClinicalTrials.gov NCT05995106. Registered on 16 August 2023.

Early elastic and viscoelastic corneal biomechanical changes after photorefractive keratectomy and small incision lenticule extraction.

To compare early changes in the corneal biomechanical parameters after photorefractive keratectomy (PRK) and small incision lenticule extraction (SMILE) and their correlations with corneal shape parameters. One hundred twenty four eyes received myopic PRK and SMILE for similar amounts of myopia. Corneal tomography with Pentacam HR, biomechanical parameters using Corvis ST, and Ocular Response Analyzer (ORA) were evaluated before and 2weeks after surgery. The change in each parameter was compared between groups, while the difference in central corneal thickness and cornea-compensated intraocular pressure measured before and after surgery were considered as covariates. A significant reduction was seen in the corneal stiffness parameter at first applanation, and an increase in deformation amplitude ratio (DAR), and integrated inverse radius (IIR) in both groups after surgery (p < 0.001) Changes in DAR, and IIR were significantly greater in the SMILE than in the PRK group (p < 0.001) Corneal hysteresis (CH) and corneal resistance factor(CRF) decreased in both SMILE and PRK groups after surgery, (p < 0.001) with no statistically significant difference between groups (p > 0.05) Among new Corvis ST parameters, DAR showed a significant correlation with changes in Ambrosio relational thickness in both groups (p < 0.05). Both techniques caused significant changes in corneal biomechanics in the early postoperative period, with greater elastic changes in the SMILE group compared to the PRK group, likely due to lower tension in the SMILE cap and thinner residual stromal bed in SMILE. There were no differences in viscoelastic changes between them, so the lower CH may reflect the volume of tissue removed.

Toward Acid and Heparin-Free Dialysis: The Regional Anticoagulation Approach

Abstract Background and hypothesis In chronic intermittent hemodialysis, heparin is the standard anticoagulant as is the use of acid-containing dialysate. Regional anticoagulation (RA) with a calcium-free, citrate-containing dialysate has been developed. We compared RA using a calcium-free, citrate-free dialysate, routinely used in our centre, to systemic heparinization. Methods In a retrospective, observational, single-centre, cross-over study, we examined 15 patients undergoing chronic hemodialysis who were at high risk of bleeding and temporarily unable to use heparin. These patients received temporary treatment with RA involving calcium-free and citrate-free dialysate. We compared the dialysis session success rates during two distinct periods: standard heparinization and RA procedure with a calcium-free and citrate-free dialysate. Results In our study of 15 patients on chronic hemodialysis which compared 30 RA sessions to 28 heparin-based anticoagulation session, we observed a 100% success rate with a median session duration of 240 minutes in both RA and heparin groups. No early extracorporeal circulation (ECC) loss was reported. However, we noted significant differences in the post-dialysis ECC thrombosis scores, with higher Global Thrombosis Index (GTI) and higher membrane coagulation scores in the RA group (p &amp;lt; 0.007 and p &amp;lt; 0.02, respectively). No hypocalcaemia or hypercalcemia symptoms occurred. Median post-filter ionized calcium levels were 0.32 [0.29–0.39] mmol/L at 30 minutes and median patient ionized calcium levels was 1.19 [1.135–1.28] mmol/L at 60 minutes. No significant difference in per-dialysis arterial blood pressure was observed between groups. Conclusion Our study evaluated the RA approach using a calcium-free, citrate-free acetate dialysate in a chronic hemodialysis centre and found it effective. Although an acid-free dialysate was not used in this study, our findings suggest it could be the next frontier in the evolution of advanced dialysis techniques.

Fast stiffness variation gripper with efficient adhesion control

The mushroom-shape gecko-inspired adhesive has been extensively studied and applied in a wide range of fields. However, current research primarily focuses on enhancing its adhesion properties, necessitating further exploration in strategies of detachment and adaptation, which significantly constrain its practical applications. In this study, a stiffness variable gripper with controllable adhesion and fast response is developed by integrating mushroom-shape adhesive with granular jamming technology. A theoretical model for the detachment of the gripper is established, indicating the effect of backing stiffness on adhesion performance, which is verified through contact area observations and adhesion experiments. The proposed modulation method demonstrates an impressive adhesion-to-detachment ratio of 92.8, with adhesion capacity of up to 41.023 N and detachment force of only 0.442 N. The switch time is remarkably fast at just 0.5 s. Additionally, the designed gripper, under pressure difference of 60 kPa, is able to stably grasp smooth objects with various shapes weighing over 2 kg, with a load-to-weight ratio of approximately 8, and a minimal power consumption of only 4.404 W. The work here presents a comprehensive understanding of adhesion modulation of fibrillar adhesive through granular jamming, and provides new insights into robust reversible adhesion design for related technologies.