High Pressure Research Articles

The Diagnostic Accuracy of Using Borderline High Office Blood Pressure Thresholds to Diagnose Masked Hypertension According to the 2017 American College of Cardiology / American Heart Association Blood Pressure Guideline.

The 2017 American College of Cardiology (ACC)/American Heart Association (AHA) BP guideline recommends ambulatory BP monitoring (ABPM) for diagnosing masked hypertension among adults not taking antihypertensive medication with borderline office BP (i.e., office systolic BP [SBP] 120 to <130 mmHg or diastolic BP [DBP] 75 to <80 mmHg). Using data from the Improving the Detection of Hypertension Study, sensitivity (SN), specificity (SP), positive predictive value (PPV), negative predictive value (NPV), and likelihood ratios for a positive and negative test of having borderline office BP (i.e. office SBP 120 to <130 mmHg or DBP 75 to <80 mmHg) for diagnosing masked hypertension (i.e. mean awake SBP ≥130 mmHg or mean awake DBP ≥80 mmHg) were determined among 263 participants who had a mean office SBP <130 mmHg and mean DBP <80 mmHg. Likelihood ratios for a positive test >10, 5 to 10, and <5 were considered strong, moderate, and weak, respectively. Likelihood ratios for a negative test <0.1, 0.1 to 0.2, and >0.2 were considered strong, moderate, and weak, respectively. Among the 263 participants, mean±SD age was 39.2±12.8 years, 62.4% were female, 38.4% had borderline office BP, and 26.2% had masked hypertension. SN, SP, PPV, and NPV were 0.754, 0.747, 0.515, and 0.895, respectively. The likelihood ratios for a positive and negative test were 2.984 (weak) and 0.330 (weak), respectively. The use of borderline office BP thresholds recommended in the 2017 ACC/AHA BP guideline did not sufficiently rule in or rule out masked hypertension.

High-pressure and low-temperature behaviour of organic ferroelectric (R)-3-quinuclidinol.

High-pressure and low-temperature structural changes in the ferroelectric phase of (R)-3-quinuclidinol are analysed. The changes in unit-cell volume and parameters are continuous both on cooling and under increasing pressure. The anisotropy of the structural strain, however, is found to be different. At high pressures, the shortest possible distances for H...H contacts are achieved. Since the deformation along the polarization axis can be related to spontaneous polarization, different piezoelectric responses may be expected on cooling and under hydrostatic compression.

Early detection of high blood pressure from natural speech sounds with graph diffusion network.

This study presents an innovative approach to cuffless blood pressure prediction by integrating speech and demographic features. With a focus on non-invasive monitoring, especially in remote regions, our model harnesses speech signals and demographic data to accurately estimate blood pressure. We found a strong correlation between our predictive model and early-stage high blood pressure, highlighting its potential for early detection. Central to our investigation is the Graph Diffusion Network (GDN) model, achieving exceptional performance with an R2 score of 0.96 and a Pearson correlation coefficient (PCC) of 0.98. In early-stage hypertension detection, the GDN model achieved an F1-Score of 0.8735±0.10 and accuracy of 0.8896±0.11. Additionally, without considering demographic features, the model still performed well, with an R2 of 0.740 and PCC of 0.764 when used alone. These results emphasize the value of combining speech and demographic features, offering a promising, non-invasive solution for blood pressure monitoring.

Effects of high hydrostatic pressure on the structural, physicochemical, and functional characteristics of buffalo milk casein.

This study applied high hydrostatic pressure (HHP) treatment to buffalo milk casein to assess the influence of different pressure levels on its structural characteristics, physicochemical properties, and functional properties. The results showed that although HHP had no marked impact on the zeta potential and secondary structure, it altered the protein's spatial structure (primarily its tertiary structure), and improved dispersion properties (such as particle size, solubility, and turbidity), as well as foaming properties. Additionally, HHP improved the antioxidant activity and antibacterial activity against Escherichia coli. However, HHP treatment negatively affected the water-holding capacity, emulsion stability, and antibacterial activity against Staphylococcus aureus. These findings suggest that HHP treatment is a potential method for modifying buffalo milk casein and provides a theoretical basis for its comprehensive utilization.

Bangia fusco-purpurea polysaccharide with ultra-high pressure assisted extraction alleviates dyslipidemia in high-fat diet induced mice.

Bangia fusco-purpurea polysaccharide (UBFP) with ultra-high pressure assisted extraction has good in vitro hypolipidemic activity. To be explored as a natural hypolipidemic agent, the alleviation effect of UBFP on in vivo dyslipidemia in high-fat diet (HFD) induced mice was further investigated. Compared with native polysaccharide (BFP), UBFP was better to reduce weight gain, fat accumulation, serum and hepatic lipid abnormalities for HFD induced mice. This might be caused by the factor that UBFP was more effective to improve the diversity and structure of gut microbiota especially with SCFAs-producing bacteria (e.g., Allprevotella and Akkermansia) increased. Moreover, UBFP could up-regulate tryptophan, 5-hydroxyindoleacetic acid, leptin and N-arachidonic acid glutamate levels, and exhibited significant differential enrichment in the pathways of lysine biosynthesis, arginine biosynthesis, and tryptophan metabolism. In addition, UBFP could regulate energy metabolism and enhance fatty acid oxidation by inhibiting PPARγ protein expression and activating AMPK and ACC signaling pathways. Overall, with ultra-high pressure assisted extraction, UBFP possessed better function of regulating lipid homeostasis, which resulted from the altered structure of polysaccharides, improved intestinal flora and metabolites. The findings can lay the theoretical foundation for the design and development of desirable polysaccharides on regulating lipid homeostasis through ultra-high pressure modification.

Nanotwinned alloys under high pressure

Nanotwinned alloys under high pressure

High pressure and high temperature synthesis of a new boron carbide phase

The dense boron carbide (B-C) phases with diamond structure are predicted to be superhard, with hardness close to that of a cubic boron nitride (c-BN). At ambient conditions, graphite-like BC3 is well characterized, firstly reported by Kouvetakis et al. In this work, we have synthesized a new B-C phase from the graphite-like BC3 in a laser-heated diamond anvil cell. Interestingly, this phase could be recoverable to ambient pressure due to dynamic stabilities. The Raman spectrum and X-ray diffraction patterns give the possible structure of this new phase.

First-principles calculations on structural stability and electronic properties of the Strontium-Argon System at High Pressure

First-principles calculations on structural stability and electronic properties of the Strontium-Argon System at High Pressure

An experimental speciation study of DME, OME1, and OME2 in a single-pulse shock tube at high pressures

The pyrolysis of dimethyl ether (DME), oxymethylene ether-1 (OME1), and oxymethylene ether-2 (OME2) and their oxidation with oxygen under three different equivalence ratios (φ = 0.5, 1.0, and 2.0) have been studied experimentally in a customized single-pulse shock tube. The measurements were carried out highly diluted in argon over a wide temperature range between 975 K and 1400 K at initial pressures behind reflected shock waves p5(t = 0) of about 16 bar. The classical single-pulse mode involving a dump tank was not employed. Instead, post-shock gas samples were extracted through a fast-acting solenoid valve located inside the end flange of the driven section of the shock tube, to reduce measurement errors from thermal boundary layers. Thirteen stable species were identified and quantified by three different gas chromatographs simultaneously, in detail, DME, OME1, OME2, methane, ethane, ethene, acetylene, carbon monoxide, carbon dioxide, molecular hydrogen, formaldehyde, methanol, and methyl formate. The temperature dependent, measured, and normalized species concentration profiles were compared with the predicted species profiles obtained by using two different chemical kinetic reaction mechanisms from the literature and an updated version of the in-house reaction model DLR Concise. In addition, speciation data of 1,1,1-trifluoroethane and nitrous oxide at elevated pressures are presented, which were used as external chemical thermometers to validate the calculated temperature behind the reflected shock wave of the single-pulse shock tube. Novelty and SignificanceIn this work, a series of more than 300 single-pulse shock tube experiments have been performed, to investigate the decomposition products of oxygenated fuels at pressures around 16 bar. To the best of our knowledge, no speciation data is yet available for this pressure regime. By comparing the data with chemical-kinetic reaction mechanisms from the literature, opportunities for model improvement have been identified, particularly regarding methanol formation, which could be further developed in the future.The presented high-pressure validation data contributes to the development of chemical-kinetic reaction models for new oxygenated fuels derived from renewable sources. By incorporating these reaction mechanisms into CFD codes, advancements in combustors and engine technology are facilitated, promoting cleaner combustion processes.

Simultaneous photocatalytic CO2 reduction and C-C coupling of benzyl alcohol under high pressure and supercritical conditions

Simultaneous photocatalytic CO2 reduction and C-C coupling of benzyl alcohol under high pressure and supercritical conditions

Advancing the C[formula omitted] low-temperature oxidation chemistry through species measurements in a rapid compression machine. Part B: n-Butane

Studying the oxidation of n-butane, a major component of LNG, is critical to improve the efficiency of transportation engines. Furthermore, its negative temperature coefficient (NTC) behavior provides insights into the oxidation of larger hydrocarbons. Several studies have investigated n-butane oxidation at engine-operating pressures using various methods, including ignition delay time (IDT) measurements in rapid compression machines (RCMs) and shock tubes, flame velocities, and species concentrations in flow reactors. While these species measurements provide deeper insights into oxidation networks than IDTs, they are limited to either low-pressure or highly diluted conditions. To address this gap, this study measures species concentrations during n-butane oxidation at 30 bar in the NTC region (742 K and 855 K, respectively), at stoichiometric and moderate dilution levels in an RCM. A novel two-valve setup allowed gas sample extraction for off-line gas chromatography-mass spectrometry analysis. Complementary IDT data were obtained in the temperature range of 680−910 K, at pressures of 15 and 30 bar, and equivalence ratios of 0.5, 1.0, and 2.0. The results suggest that while current n-butane models reasonably predict its autoignition characteristics, they fall short in predicting the formation of key oxidation intermediates at engine-relevant conditions. In this context, the n-butane submechanism within the NUIGMech1.3 framework was updated. Modifications involve recently computed thermochemical data for critical intermediates and adjustments to rate constants, using analogies with structurally similar molecules such as n-propane and n-pentane. The present model reproduces reasonably well both the measured IDT and species concentrations documented herein and data from the literature. Nevertheless, the model slightly underestimates the reactivity within the NTC domain and the formation of some intermediates at the NTC peak. This study highlights the importance of integrating species concentration and IDT measurements at application-relevant conditions to refine kinetic mechanisms and significantly advances the understanding of C4 hydrocarbon oxidation chemistry.Novelty and Significance StatementThe novelty of this research lies in the measurement of species concentrations during the ignition delay of n-butane mixtures in an RCM at high pressures near the NTC minimum and maximum using a novel two-valve gas sampling setup. This, in combination with new thermochemical data and rate rules based on analogies with propane and n-pentane, allowed the refinement of the n-butane sub-mechanism within the NUIGMech1.3 framework.By combining species concentration measurements with ignition delay times in the RCM, this study examines the oxidation of n-butane, a major component of LPG, under conditions that closely mimic engine environments, overcoming the limitations of previous studies limited to highly dilute conditions. This research is part of a broader investigation of C4 oxidation chemistry, along with our companion work on 1-butene. The resulting kinetic model is capable of reproducing most of the available n-butane and 1-butene validation targets.

Urban green spaces as regulators of thermal comfort for different age groups in the context of heat waves

ABSTRACT This study aims to bolster the resilience of cities in the face of heat wave disasters by considering climate regulation and residents’ thermal sensation. We chose a humid-hot climatic region for the experiment and used blend of objective climatic measurements and subjective questionnaires to analyze the thermal environment characteristics of different spatial forms of green spaces and the thermal sensation of people from different socio-demographic groups. The results demonstrate that (1) waterfront vegetation (semi-enclosed spaces) and mixed vegetation area (semi-open spaces) are the most effective in regulating urban microclimate effects and improving subjective thermal experience, (2) the subjective thermal sensation ranges reported by individuals consistently exceed the corresponding grading criteria under high heat pressure defined by the Wet Bulb Globe Temperature (WBGT), and (3) both elders (>65 years old) and children (<14 years old) exhibit weaker thermal sensitivity and a gentler response to temperature changes than people in other age groups. These results imply that green spaces with different structures and compositions have different effects on people’s thermal perception and people from different age groups respond heat waves differently. Consequently, it is necessary to implement real-time temperature monitoring in areas where these individuals gather, and to strengthen the early warning systems and guidance for their outdoor activities. These findings provide a reference for optimizing urban spatial forms and developing integrated ‘Heat-Health Action Plan’ in humid-hot regions around the world.

Debris production, transport, and sedimentation at high fluid pressures in subglacial conduits

Debris production, transport, and sedimentation at high fluid pressures in subglacial conduits

Low friction hydrogel with diclofenac eluting ability for dry eye therapeutic contact lenses.

When placed in the eye, contact lenses (CLs) disturb the tear fluid and affect the natural tribological behaviour of the eye. The disruption in the contact mechanics between the ocular tissues can increase frictional shear stress and ocular dryness, causing discomfort. Ultimately, continuous CLs wear can trigger inflammation which is particularly critical for people suffering from dry eye. In this work, a double strategy was followed to obtain therapeutic daily disposable CLs for dry eye: a hydroxyethyl methacrylate (HEMA) based hydrogel was coated with two natural polysaccharides, chitosan (CHI) and hyaluronic acid (HA) and posteriorly loaded with an anti-inflammatory drug (diclofenac, DCF). Material sterilisation was carried out by high hydrostatic pressure (HHP) combined with moderate temperature. The friction coefficient (μ) was determined in the presence of different tear biomolecules (cholesterol, lysozyme and albumin) using a nanotribometer. Drug release experiments were performed in static and in hydrodynamic conditions. The material was extensively characterised, regarding surface morphology/topography, optical properties, water content and swelling behaviour, wettability, ionic and oxygen permeability and mechanical properties. It was found that the coating did not impair the physico-chemical properties relevant for the material's application in CLs. Besides, it also ensured a sustained release of DCF for 24h in tests performed in hydrodynamic conditions that simulate those found in the eye, increasing significantly the amount of drug released. It reduced friction, improving the lubrication ability of the hydrogel, and presented antibacterial properties against S. aureus, P. aeruginosa and B. Cereus. The coated samples did not reveal any signs of cytotoxicity or potential eye irritation. Overall, the coating of the hydrogel may be useful to produce daily CLs able to alleviate dry eye symptoms and the discomfort of CLs wearers.

Tissue oxygenation in response to low-load and high-load back squats with continuous blood flow restriction in athletes

ABSTRACT To determine muscle oxygenation with continuous blood flow restriction (BFR) training in high load (HL), 80% one-repetition maximum (1RM) and low load (LL), 30% 1RM squat exercises. In week-2 of a 4-week resistance training programme as part of their 3-set training routine, two groups of athletes (n = 4 each), one performing HL training with low cuff pressure (20% arterial occlusion pressure (AOP)), the other LL training with high cuff pressure (60% AOP) had muscle oxygenation assessed with near-infrared spectrophotometry (NIRS), arterial oxygen saturation (SPO2), heart rate (HR), barbell velocity and ratings of perceived exertion (RPE) during barbell back squats (BBS). Changes in the vastus lateralis oximetry were compared to pre- and post-training squat (1RM). Across athletes, there were significant associations between two pre-set-3 exercise variables and post-training 1RM, Tissue Saturation Index (TSI) (R2 = 0.92, p < 0.0002) and HHb concentration (R2 = 0.79, p < 0.003). Generalised regression models indicated that TSI % and HHb concentrations before and after set 3 timepoints were significant predictors of post-training 1RM in the LL group (R2 = 0.99, BIC = −24.9). Well-tolerated continuous LL-BFR training provided greater increases in strength than HL-BFR in athletes.

Study on the effect of occupational exposure on hypertension of steelworkers based on Lasso-Logistic regression model.

This study aimed to use a stable and predictive method: Lasso regression model to analyze hypertension's influencing factors and explore the interactions between occupational exposures. This has been a nested case-control study. The case group consisted of 959 patients with high blood pressure found during the study. 959 hypertensive patients, matched 1:1 from the cohort based on the age ±2 years and same gender distribution, served as the control group. Logistic regression has been performed to analyze the relationship between occupational exposures and hypertension after the variables were screened by the Lasso regression model and to explore the interactions between the various occupational exposures. The incidence rate of hypertension among steelworkers was 33.95%. Noise, dust, high temperature, carbon monoxide (CO), and shift work have been found to be significantly associated with the risk of hypertension, which is 1.329, 1.370, 1.900, 1.309, and 1.427 times higher than that of the control group, respectively. In addition, a multiplicative interaction between dust and noise has been found (P=0.038). The study suggested that exposure to dust, high temperature, CO, noise, and shift work increases the risk of hypertension among steelworkers and that the risk of hypertension is more pronounced among workers exposed to both dust and noise.

Abstract TP117: Efficacy And Safety Of Ambulance-Based Prehospital Transdermal Glyceryl Trinitrate In Patients With Acute Presumed Stroke. A Meta-Analysis Of Randomized Controlled Trials.

Background: Uncontrolled high blood pressure is a risk factor for acute stroke and a predictor of poor stroke outcomes. Less is known about the efficacy and safety of early ambulance-delivered blood pressure reduction on clinical and functional outcomes in patients with undifferentiated acute stroke. Methods: PubMed, Scopus, and Cochrane databases were searched for randomized controlled trials that compared intervention (with glyceryl trinitrate) to usual blood pressure care or sham in patients with undifferentiated acute stroke; the outcomes of day 90 modified Rankin scale (mRS) maximum score of 6, EuroQol-5D score, National Institutes of Health Stroke Scale (NIHSS ) score at hospital admission, death within 90 days, Barthel index at 90 days, and home time. Heterogeneity was examined using I 2 statistics. Results: We included 3 RCTs with 3547 Patients, of whom 388 received intervention with glyceryl trinitrate. The pooled results of the included 3 RCTs comparing Intervention with glyceryl trinitrate to usual care or sham treatment showed that the death within 90 days (21.9% vs 21.1% respectively; OR = 1.05; 95% CI [0.89, 1.24]; I 2 = 0%; p = 0.546), EuroQol-5D-5L score (MD = -0.00; 95% CI [-0.03, 0.03]; I 2 = 0%; p = 0.98), NIHSS score at hospital admission (MD = 0.18; 95% CI [-0.70, 1.06]; I 2 = 0%; p = 0.69), day 90 mRS maximum score at 6 (MD = 0.01; 95% CI [-0.25, 0.27]; I 2 = 0%; p = 0.94), NIHSS score at 24 hours (MD = 0.56; 95% CI [-0.16, 1.27]; I 2 = 0%; p = 0.13), Barthel index at 90 days (MD = -2.56; 95% CI [-7.90, 2.78]; I 2 = 0%; p = 0.35), and home time (MD = 0.22 days; 95% CI [-5.02, 5.46]; I 2 = 0%; p = 0.93) were not statistically different between the intervention and the usual care groups. Conclusion: These findings suggest that early ambulance-delivered blood pressure reduction does not have superior efficacy and safety profiles for clinical and functional outcomes compared with usual care or sham treatment in patients with undifferentiated acute stroke.

Modelling hydrogen deblending from natural gas using Pd-based dense metallic membranes with an empirical polarization model

Low carbon hydrogen can be produced using excess of electric power and further stored into the existing natural gas grid. Deblending processes are required at the end-users side. However, conventional technologies such as adsorption methods can be complex, especially at the small scales, making the investment not convenient. Membrane technology is gaining interest. In scientific literature, Pd-based dense metallic membranes were already identified as a potential solution to separate high purity hydrogen. They can also be coupled with electrochemical hydrogen pump and TSA. However, Pd-based membrane potentiality had not yet been deeply investigated. In this article, a new empirical correlation for concentration polarization losses is found. Thanks to its simplicity and flexibility, it is used to show how an appropriate design of the separation modules can lead to outperform benchmark performance. Different scenarios, with blending at 5%, 10% and 20% and at low (8 bar), mid (40 bar) and high (66 bar) grid pressure are studied to separate 25 kg/day of pure hydrogen. Separation costs obtained with 10% hydrogen blending are below 4.44 €/kg even at low pressure, outperforming benchmark estimations using PSA, that resulted 7.64 €/kg. Polarization correlation is recommended to further improve module design in H2 deblending.

Juggle Between Work, Home, and Stress; A Qualitative Analysis Using Nvivo-12 on Working Women During the COVID-19 Pandemic

Background: India and other parts of the world have witnessed a health emergency due to COVID-19 that immensely affected the globe. These infectious diseases changed the lives of people, and the condition of working women worsened due to the responsibility of work, home, children, family, house, etc., altogether simultaneously. In a patriarchal society like India, where women are considered as ‘nurturing sex’ where domestic chores and care giving responsibilities are shouldered on women, the juggle between work and home elevated the work demand and heightened the level of stress. Based on the background discussed above, this research is an attempt to address the condition of working women the juggling between work and home elevated stress, work pressure amid COVID-19. Introduction: The world has been struggling with the greatest health crisis for the last two and a half years, affecting everyone’s life, especially working women. The condition of working women has worsened by bearing the heap of responsibilities of work, home, children, family, house, etc., which undoubtedly results in stress, frustration, and anger affecting women’s physical and mental health. This paper is to study the condition of working women who are juggling between work and home amid this COVID-19 pandemic. Methods: For conducting the comprehensive study, a questionnaire was designed, which consisted of 14 questions excluding the demographic information, namely Name, Age, Gender, Profession, Experience, etc. Questionnaires were floated to 60 working women under different job profiles. Convenience Sampling was used to collect the data. Out of a sample of 60, 50 women recorded their responses via Google Sheets, and 38 questionnaires were finally used for analysis. The authors have utilized qualitative data analysis techniques to address the issue with the help of computer-assisted qualitative data analysis software NVIVO. For analyzing the qualitative data, NVIVO 12 was used by applying three tools Word Cloud Analysis, thematic analysis, and sentiments analysis. Results: The findings of the study show that working women are facing continuous challenges and are under stress due to multiple roles, responsibilities, and work demands since the onset of COVID-19. It is supported by Word Cloud Analysis, thematic analysis, and sentiment analysis. Conclusion: The outbreak of this COVID-19 pandemic, and its exceptional impact on lives, has generated an array of challenges in everyone’s life, but it shattered the lives of working women. The objective of this research is to unearth the stress in working women’s life amid COVID-19 due to the juggling between personal and professional life simultaneously. Results show that amid COVID-19, working women are under stress due to familial responsibility, household chores, work demands, caregiving, etc., all simultaneously without any breather. This societal stereotype lays high pressure and exceptions on working women leading to stress affecting the personal well-being and health of the woman.

Influence of high pressure on structural, electronic, magnetic, optical, mechanical and thermoelectric properties of rare-earth nitrides RE3+N3− (RE3+ = Sm3+, Eu3+, Gd3+)

Influence of high pressure on structural, electronic, magnetic, optical, mechanical and thermoelectric properties of rare-earth nitrides RE3+N3− (RE3+ = Sm3+, Eu3+, Gd3+)