Changes In Pressure Research Articles

Endobronchial Phenylephrine in Airway Bleeding During Bronchoscopy Does not Cause Hypertension: A Retrospective Observational Study.

Bleeding is a known complication during bronchoscopy, with increased incidence in patients undergoing a more invasive procedure. Phenylephrine is a potent vasoconstrictor that can control airway bleeding when applied topically and has been used as an alternative to epinephrine. The clinical effects of endobronchial phenylephrine on systemic vasoconstriction have not been clearly evaluated. Here, we compared the effects of endobronchial phenylephrine versus cold saline on systemic blood pressure. In all, 160 patients who underwent bronchoscopy and received either endobronchial phenylephrine or cold saline from July 1, 2017 to June 30, 2022 were included in this retrospective observational study. Intra-procedural blood pressure absolute and percent changes were measured and compared between the 2 groups. There were no observed statistical differences in blood pressure changes between groups. The median absolute change between the median and the maximum intra-procedural systolic blood pressure in the cold saline group was 29mmHg (IQR 19 to 41) compared with 31.8mmHg (IQR 18 to 45.5) in the phenylephrine group. The corresponding median percent changes in SBP were 33.6 % (IQR 18.8 to 39.4) and 28% (IQR 16.8 to 43.5) for the cold saline and phenylephrine groups, respectively. Similarly, there were no statistically significant differences in diastolic and mean arterial blood pressure changes between both groups. We found no significant differences in median intra-procedural systemic blood pressure changes comparing patients who received endobronchial cold saline to those receiving phenylephrine. Overall, this argues for the vascular and systemic safety of phenylephrine for airway bleeding as a reasonable alternative to epinephrine.

Role of Vitamin D in Management of Diabetes and Unresolved Cardiovascular Diseases.

Vitamin D deficiency is becoming a widely recognized global health issue. Serum values of 25-(OH) vitamin D (<20 ng/ml) are used to identify vitamin D deficiency. By prompting vascular endothelial cells to activate their nuclear receptor in cardio-myocytes, Vitamin D regulates obesity, Renin-angiotensin system (RAS), energy consumption, and pancreatic cell function. Vitamin D deficiency has been associated with diabetes, asthma, hyperlipidaemia, and pulmonary hypertension in humans. PubMed and Google Scholar databases were utilised to search the literature on vitamin D and related diseases. It is also linked to an elevated risk of death and heart disease. On the other hand, metaanalyses of vitamin D intervention and trials have found no substantial changes in insulin sensitivity, lipid markers, or blood pressure, which result in the association between deficiency of vitamin D and cardiovascular disease. In this review, we present the most recent research on the effects of Vitamin D therapy on various cardiovascular diseases and diabetes, and explain the underlying mechanisms.

Research on the Coordinated Development of Digital Economy, Green Technology Innovation, and Ecological Environment Quality—A Case Study of China

Based on panel data from 285 prefecture-level cities in China from 2019 to 2023, the synergistic effects of the digital economy, green technology innovation, and ecological environment quality were analyzed. First, using the entropy method, the measurement dimensions of the indicators of the digital economy, green technology innovation, and ecological environment quality were obtained. Second, employing a neural network model with these measurements as input variables, the interactive relationship among the digital economy, green technology innovation, and ecological environment quality was explored. Finally, based on the calculation results of the neural network model, the importance and impact of each input parameter on ecological environment quality were determined using weight analysis methods. The research findings indicate: (1) Utilizing the entropy method, the measurement dimensions of the indicators of the digital economy, green technology innovation, and ecological environment quality were obtained. Analysis of each indicator measurement reveals that environmental pressure has a significant impact on ecological environment quality, with significant differences in environmental pressure among different regions. Industrial digitization emerges as the core factor influencing the digital economy, being the most significant driving effect, followed by digital industrialization. Green technology innovation is crucial for promoting environmental protection and achieving high-quality green economic development. (2) Based on the neural network model, the interactive relationship among the digital economy, green technology innovation, and ecological environment quality was revealed. The results indicate that the digital economy has a direct impact on improving ecological environment quality. The relationship between the digital economy and the ecological environment exhibits nonlinear effects, with the rate of change in environmental pressure and environmental status measurements initially increasing significantly and then gradually slowing down as the measurement levels of digital industrialization and industrial digitization increase. Improvement in digital governance and data value measurement levels will contribute to enhancing environmental status and environmental governance levels. (3) Through weight analysis, it was found that in terms of direct effects, industrial digitization, and digital industrialization have the most significant impact on environmental pressure, with importance coefficients of 0.45 and 0.3, respectively, while data valorization has the least impact. Regarding intermediary effects, industrial digitization and green technology innovation have the most significant impact on environmental pressure, while digital governance and green technology innovation have a relatively clear impact on environmental status and environmental governance. These results lay the foundation for promoting the coordinated cooperation between the digital economy and green technology innovation and for advancing the establishment of a win–win situation between economic development and environmental protection.

How effective is proximal fibular osteotomy in redistributing joint pressures? Insights from an HTO comparative in-silico study

BackgroundKnee osteoarthritis (KOA) represents a widespread degenerative condition among adults that significantly affects quality of life. This study aims to elucidate the biomechanical implications of proximal fibular osteotomy (PFO), a proposed cost-effective and straightforward intervention for KOA, comparing its effects against traditional high tibial osteotomy (HTO) through in-silico analysis.MethodsUsing medical imaging and finite element analysis (FEA), this research quantitatively evaluates the biomechanical outcomes of a simulated PFO procedure in patients with severe medial compartment genu-varum, who have undergone surgical correction with HTO. The study focused on evaluating changes in knee joint contact pressures, stress distribution, and anatomical positioning of the center of pressure (CoP). Three models are generated for each of the five patients investigated in this study, a preoperative original condition model, an in-silico PFO based on the same original condition data, and a reversed-engineered HTO in-silico model.ResultsThe novel contribution of this investigation is the quantitative analysis of the impact of PFO on the biomechanics of the knee joint. The results provide mechanical evidence that PFO can effectively redistribute and homogenize joint stresses, while also repositioning the CoP towards the center of the knee, similar to what is observed post HTO. The findings propose PFO as a potentially viable and simpler alternative to conventional surgical methods for managing severe KOA, specifically in patients with medial compartment genu-varum.ConclusionThis research also marks the first application of FEA that may support one of the underlying biomechanical theories of PFO, providing a foundation for future clinical and in-silico studies.

Noradrenaline-induced changes in cerebral blood flow in health, traumatic brain injury and critical illness: a systematic review with meta-analysis.

Noradrenaline is a standard treatment for hypotension in acute care. The precise effects of noradrenaline on cerebral blood flow in health and disease remain unclear. We systematically reviewed and synthesised data from studies examining changes in cerebral blood flow in healthy participants and patients with traumatic brain injury and critical illness. Twenty-eight eligible studies were included. In healthy subjects and patients without critical illness or traumatic brain injury, noradrenaline did not significantly change cerebral blood flow velocity (-1.7%, 95%CI -4.7-1.3%) despite a 24.1% (95%CI 19.4-28.7%) increase in mean arterial pressure. In patients with traumatic brain injury, noradrenaline significantly increased cerebral blood flow velocity (21.5%, 95%CI 11.0-32.0%), along with a 33.8% (95%CI 14.7-52.9%) increase in mean arterial pressure. In patients who were critically ill, noradrenaline significantly increased cerebral blood flow velocity (20.0%, 95%CI 9.7-30.3%), along with a 32.4% (95%CI 25.0-39.9%) increase in mean arterial pressure. Our analyses suggest intact cerebral autoregulation in healthy subjects and patients without critical illness or traumatic brain injury., and impaired cerebral autoregulation in patients with traumatic brain injury and who were critically ill. The extent of mean arterial pressure changes and the pre-treatment blood pressure levels may affect the magnitude of cerebral blood flow changes. Studies assessing cerebral blood flow using non-transcranial Doppler methods were inadequate and heterogeneous in enabling meaningful meta-analysis. Noradrenaline significantly increases cerebral blood flow in humans with impaired, not intact, cerebral autoregulation, with the extent of changes related to the severity of functional impairment, the extent of mean arterial pressure changes and pre-treatment blood pressure levels.

A computational fluid dynamics study to assess the impact of coughing on cerebrospinal fluid dynamics in Chiari type 1 malformation

Chiari type 1 malformation is a neurological disorder characterized by an obstruction of the cerebrospinal fluid (CSF) circulation between the brain (intracranial) and spinal cord (spinal) compartments. Actions such as coughing might evoke spinal cord complications in patients with Chiari type 1 malformation, but the underlying mechanisms are not well understood. More insight into the impact of the obstruction on local and overall CSF dynamics can help reveal these mechanisms. Therefore, our previously developed computational fluid dynamics framework was used to establish a subject-specific model of the intracranial and upper spinal CSF space of a healthy control. In this model, we emulated a single cough and introduced porous zones to model a posterior (OBS-1), mild (OBS-2), and severe posterior-anterior (OBS-3) obstruction. OBS-1 and OBS-2 induced minor changes to the overall CSF pressures, while OBS-3 caused significantly larger changes with a decoupling between the intracranial and spinal compartment. Coughing led to a peak in overall CSF pressure. During this peak, pressure differences between the lateral ventricles and the spinal compartment were locally amplified for all degrees of obstruction. These results emphasize the effects of coughing and indicate that severe levels of obstruction lead to distinct changes in intracranial pressure.

Interplay Between Fluid Intrusion and Aseismic Stress Perturbations in the Onset of Earthquake Swarms Following the 2020 Alex Extreme Rainstorm

AbstractThe 2020 Alex storm in southern France led to localized extreme rainfall exceeding 600 mm in less than 24 hr. In the 100 days following the storm, a series of small earthquakes swarm occurred beneath the Tinée valley, a region characterized by a low background deformation. To gain insight into the mechanisms controlling swarm evolution, we used an enhanced seismic catalog to detect 188 events. These events exhibited magnitudes comprised between −1.03 and 2.01, and 78 of them were relocated using relative locations at an average depth of 3–4 km. Additionally, we estimated the directions and velocities of seismicity migration. Our analyses reveal multiple episodes of hypocenter expansion and migration within a fluid‐saturated fault system. Observations provide evidence of a bi‐directional seismicity migration marked by dual velocities within a swarm. The northward seismicity migration aligns with velocities indicative of aseismic slip (∼130 m/hr), while the southward migration corresponds to velocities associated with fluid pressure diffusion (∼5 m/hr). This migration pattern underscores the interplay of multiple physical mechanisms in both triggering and driving earthquakes. A stress‐driven model based on rate‐and‐state friction successfully explains the overall evolution of observed seismicity, whereas a fluid‐driven model fails to reproduce the data. Our observations and models suggest that fluid pressure changes resulting from intense rainfall caused aseismic slip in the shallow portion of the crust. We hypothesize that aseismic deformation serves as the driving force for the earthquake swarms, coupled with the invasion of pressurized fluid due to diffusing rainfall.

Ophthalmic artery Doppler in women with hypertensive disorders of pregnancy: relationship to blood pressure control and renal dysfunction at 6-9 weeks postnatally.

To examine the postnatal course of ophthalmic artery (OA) Doppler in women with hypertensive disorders of pregnancy (HDP) and to evaluate the correlation between OA Doppler parameters and poor postnatal blood pressure control and renal dysfunction at 2-3 weeks and 6-9 weeks postnatally. This was a prospective cohort study of women with a singleton pregnancy and HDP seen at a tertiary pregnancy hypertension clinic between 2019 and 2021. Three visits were included: Visit 1, the last visit to the antenatal hypertension clinic within 2 weeks prior to delivery; Visit 2, at 2-3 weeks postnatally; and Visit 3, at 6-9 weeks postnatally. At each visit, maternal demographic characteristics, medical history, blood pressure and OA Doppler were obtained. In addition, fetal growth and fetal Dopplers were examined antenatally and, at 6-9 weeks postnatally, estimated glomerular filtration rate and proteinuria were quantified. Study participants were divided into four hypertension groups, according to longitudinal changes in blood pressure at the three visits. For the postnatal visits, hypertension was defined as systolic blood pressure (SBP) ≥ 140 mmHg and/or diastolic blood pressure (DBP) ≥ 90 mmHg in the absence of antihypertensive medication, and SBP ≥ 130 mmHg and/or DBP ≥ 80 mmHg whilst taking antihypertensives. Group 1 was hypertensive at all three visits; Group 2 was hypertensive at Visits 1 and 2 but normotensive at Visit 3; Group 3 was hypertensive at Visits 1 and 3 but normotensive at Visit 2; and Group 4 was hypertensive at Visit 1 but normotensive at Visits 2 and 3. The longitudinal changes in mean arterial pressure (MAP), peak systolic velocity (PSV) 1, PSV2 and the ratio of PSV2/PSV1 over the three timepoints were examined by a repeated-measures, multilevel, linear mixed-effects analysis, controlling for maternal age, weight at presentation and use of antihypertensive medication. In addition, we examined the longitudinal change in OA Doppler parameters in women with different degrees of postnatal blood pressure control and in those with and those without renal dysfunction at 6-9 weeks postnatally. A total of 108 women were recruited to the study, of whom 86 had new-onset hypertension and 22 had chronic hypertension. When controlling for maternal age, weight at presentation and use of antihypertensive medication, a significant decline in log10 MAP (P < 0.001), log10 PSV1 (P < 0.001) and log10 PSV2 (P = 0.01) was seen between Visits 1 and 3. Log10 PSVR did not change with time. When assessing OA Doppler against hypertension group, log10 PSV1 and log10 PSV2 did not differ between the hypertension groups, whilst Group 4 had a lower log10 PSVR compared with Group 1 (P < 0.01), Group 2 (P = 0.03) and Group 3 (P < 0.01). At 6-9 weeks postnatally, log10 PSVR was lower in those without compared to those with renal dysfunction (-0.021, P = 0.01), whilst log10 MAP, log10 PSV1 and log10 PSV2 values did not differ. Log10 PSVR did not change with time and remained at -0.12 (95% CI, -0.13 to -0.11) across the three visits. In women with HDP, the OA-PSVR was significantly higher in those with labile or persistently raised blood pressure postnatally compared to women whose blood pressure normalized. Similarly, the OA-PSVR at 6-9 weeks postnatally was significantly higher in women with renal dysfunction vs those without dysfunction. © 2023 International Society of Ultrasound in Obstetrics and Gynecology.

Methods Used to Estimate Reservoir Pressure Performance: A Review

Reservoir pressure plays a significant role in all reservoir and production engineering studies. It is crucial to characterize petroleum reservoirs: by detecting fluid movement, computing oil in place, and calculating the recovery factor. Knowledge of reservoir pressure is essential for predicting future production rates, optimizing well performance, or planning enhanced oil recovery strategies. However, applying the methods to investigate reservoir pressure performance is challenging because reservoirs are large, complex systems with irregular geometries in subsurface formations with numerous uncertainties and limited information about the reservoir's structure and behavior. Furthermore, many computational techniques, both numerical and analytical, have been utilized to examine reservoir pressure performance. This paper summarizes the concepts and applications of traditional and novel ways to investigate reservoir pressure changes over time. It provides a comprehensive review that assists the reader in recognizing and distinguishing between various techniques for obtaining an accurate description of reservoir pressure behavior during production, such as the reservoir simulation method, material balance equation approach, time-lapse seismic data, and modern artificial intelligence methods. Thus, the central concept of these procedures and a list of the authors' research are discussed.

Effects of intrarenal pelvic infusion of tumour necrosis factor-α and interleukin 1-β on reno-renal reflexes in anaesthetised rats.

Reno-renal reflexes are disturbed in cardiovascular and hypertensive conditions when elevated levels of pro-inflammatory mediators/cytokines are present within the kidney. We hypothesised that exogenously administered inflammatory cytokines tumour necrosis factor alpha (TNF-α) and interleukin (IL)-1β modulate the renal sympatho-excitatory response to chemical stimulation of renal pelvic sensory nerves. In anaesthetised rats, intrarenal pelvic infusions of vehicle [0.9% sodium chloride (NaCl)], TNF-α (500 and 1000 ng/kg) and IL-1β (1000 ng/kg) were maintained for 30 min before chemical activation of renal pelvic sensory receptors was performed using randomized intrarenal pelvic infusions of hypertonic NaCl, potassium chloride (KCl), bradykinin, adenosine and capsaicin. The increase in renal sympathetic nerve activity (RSNA) in response to intrarenal pelvic hypertonic NaCl was enhanced during intrapelvic TNF-α (1000 ng/kg) and IL-1β infusions by almost 800% above vehicle with minimal changes in mean arterial pressure (MAP) and heart rate (HR). Similarly, the RSNA response to intrarenal pelvic adenosine in the presence of TNF-α (500 ng/kg), but not IL-1β, was almost 200% above vehicle but neither MAP nor HR were changed. There was a blunted sympatho-excitatory response to intrapelvic bradykinin in the presence of TNF-α (1000 ng/kg), but not IL-1β, by almost 80% below vehicle, again without effect on either MAP or HR. The renal sympatho-excitatory response to renal pelvic chemoreceptor stimulation is modulated by exogenous TNF-α and IL-1β. This suggests that inflammatory mediators within the kidney can play a significant role in modulating the renal afferent nerve-mediated sympatho-excitatory response.

Design of smoke detection system using deep learning and sensor fusion with recursive feature elimination cross-validation

The fire safety system is an important component that controls material and immaterial losses. Fire disasters are generally indicated by the appearance of excess smoke and changes in temperature, pressure, and changes in other parameters in the environment. Conventional smoke sensors are limited in reading parameter changes around their environment, making them less effective in early fire detection. This study aims to design a smoke detection system as an early fire detection system, using sensor fusion based on deep learning using the recursive feature elimination method with cross-validation (RFECV) using a random forest classifier used to select optimal parameters from public datasets as the basis for determining the sensor to be used. Based on the RFECV optimal feature, a deep learning algorithm was performed and obtained an accuracy of 0.99, a precision of 0.99, a recall of 1.00, and an F1 score of 0.99, with a latency time of 34.02 μs, which is 71.76% times faster than the original model.

25-GAUGE VERSUS 27-GAUGE VITRECTOMY FOR MANAGEMENT OF VITREORETINAL DISEASES: A Large Prospective Randomized Trial.

To compare the safety and performance clinical outcomes of the 27-gauge (G) two-dimensional cutting vitrectomy probe versus a standard 25-G probe for retinal procedures. In this large randomized prospective study, all candidates for epiretinal membrane or macular hole surgery were randomized to the 27-G group or 25-G group. Outcome measures included surgery time, changes in best-corrected distance visual acuity, intraocular pressure, and central macular thickness between baseline and 1-month and 3-month follow-up time points. Moreover, intraoperative and postoperative complications were evaluated as well as the rate of sutureless vitrectomy. A total of 463 patients were included in this study, 227 patients in the 27-G group and 236 patients in the 25-G group. A similar total surgery time was found between both groups ( P = 0.0911). Similar best-corrected distance visual acuity and central macular thickness changes were observed between baseline and the 1-month and 3-month follow-up visits. No significant differences were reported in intraoperative and postoperative complications rates. The rate of sutureless vitrectomy was 96.5% for the 27-G group and 91.1% for the 25-G group ( P = 0.0170). These results suggest that 27-G vitrectomy probe is similar to 25-G probe in surgery time and complications, while decreasing the need for vitrectomy sutures.

Asymmetric Dimethylarginine and NT-proBNP Levels Provide SynergisticInformation in PulmonaryArterial Hypertension.

Plasma asymmetric dimethylarginine (ADMA) is elevated in pulmonary arterial hypertension (PAH) and is associated with unfavorable outcomes. The aim of this study was to assess changes in ADMA plasma levels for monitoring disease progression and outcomes during PAH-specific therapy. ADMA was measured at baseline and after at least 6months of follow-up using enzyme-linked immunosorbent assay and high-performance liquid chromatography. Changes in ADMA were analyzed in relation to changes in established PAH markers, including hemodynamic status, N-terminal pro-brain natriuretic peptide (NT-proBNP) and risk assessment scores. Impact on survival was assessed using Kaplan-Meier curves and Cox proportional hazards models. Between 2008 and 2019, ADMA samples were collected prospectively from 215 patients with PAH. Change in ADMA plasma level was a predictor of disease progression and survival. ΔADMA (median-0.03μmol/L; 95%CI:-0.145 to 0.0135) was correlated with change in mean pulmonary arterial pressure (P< 0.005; rS=0.287) but was not significantly correlated with ΔNT-proBNP (P=0.056; rS=0.135). Patients with decreased ADMA plasma levels at follow-up had better 3-year and 5-year survival rates (88% and 80%, respectively, vs 72% and 53% in those without decreases in ADMA) (P< 0.005; pulmonary hypertension-related mortality or lung transplantation). Patients with decreases in both ADMA and NT-proBNP had better survival rates compared with patients in whom only 1 parameter improved (P< 0.005). ΔADMA was a significant predictor of survival in Cox regression analysis and also when corrected for ΔNT-proBNP (HRs: 1.27 and 1.35, respectively; P< 0.005). ADMA and NT-proBNP provide synergistic prognostic information for patients with PAH. ADMA could be used as an objective and distinct biomarker for monitoring treatment response in PAH.

Evaluation of a 4-week interdisciplinary primary care cardiovascular health programme: impact on knowledge, Mediterranean Diet adherence and biomarkers

BackgroundCardiovascular disease (CVD) is the second-leading cause of death among Canadians. Clinical practice guidelines suggest that improvements to lifestyle, including dietary intake, can reduce the risk of CVD.ObjectivesThe primary aim...

The impact of hypovolemia and PEEP on recirculation in venovenous ECMO: an experimental porcine model

BackgroundRecirculation is a common problem in venovenous extracorporeal membrane oxygenation (VV ECMO) and may limit the effect of ECMO treatment due to less efficient blood oxygenation or unfavorable ECMO and ventilator settings. The impact of hypovolemia and positive end expiratory pressure (PEEP) on recirculation is unclear and poorly described in guidelines, despite clinical importance. The aim of this study was to investigate how hypovolemia, autotransfusion and PEEP affect recirculation in comparison to ECMO cannula distance and circuit flow.MethodsIn anesthetized and mechanically ventilated pigs (n = 6) on VV ECMO, we measured recirculation fraction (RF), changes in recirculation fraction (∆RF), hemodynamics and ECMO circuit pressures during alterations in PEEP (5 cmH2O vs 15 cmH2O), ECMO flow (3.5 L/min vs 5.0 L/min), cannula distance (10–14 cm vs 20–26 cm intravascular distance), hypovolemia (1000 mL blood loss) and autotransfusion (1000 mL blood transfusion).ResultsRecirculation increased during hypovolemia (median ∆RF 43%), high PEEP (∆RF 28% and 12% with long and short cannula distance, respectively), high ECMO flow (∆RF 49% and 28% with long and short cannula distance, respectively) and with short cannula distance (∆RF 16%). Recirculation decreased after autotransfusion (∆RF − 45%).ConclusionsIn the present animal study, hypovolemia, PEEP and autotransfusion were important determinants of recirculation. The alterations were comparable to other well-known factors, such as ECMO circuit flow and intravascular cannula distance. Interestingly, hypovolemia increased recirculation without significant change in ECMO drainage pressure, whereas high PEEP increased recirculation with less negative ECMO drainage pressure. Autotransfusion decreased recirculation. The findings are interesting for clinical studies.

Mass–Radius Relationships and Contraction of Condensed Planets by Cooling or Despinning

Condensed planets contract or expand as their temperature changes. With the exception of the effect of phase changes, this phenomenon is generally interpreted as being solely related to the thermal expansivity of the planet’s components. However, changes in density affect pressure and gravity and, consequently, the planet’s compressibility. A planet’s radius is also linked to its rate of rotation. Here again, changes in pressure, gravity, and compressibility are coupled. In this article we clarify how the radius of a condensed planet changes with temperature and rotation, using a simple and rigorous thermodynamic model. We consider condensed materials to obey a simple equation of state which generalizes a polytopic EoS as temperature varies. Using this equation, we build simple models of condensed planet’s interiors including exoplanets, derive their mass–radius relationships, and study the dependence of their radius on temperature and rotation rate. We show that it depends crucially on the value of ρ s gR/K s (ρ s being surface density, g gravity, R radius, K s surface incompressibility). This nondimensional number is also the ratio of the dissipation number which appears in compressible convection and the Gruneïsen mineralogic parameter. While the radius of small planets depends on temperature, this is not the case for large planets with large dissipation numbers; Earth and a super-Earth like CoRoT-7b are in something of an intermediate state, with a moderately temperature-dependent radius. Similarly, while the radius of these two planets is a function of their rotation rates, this is not the case for smaller or larger planets.

Investigation of Crack Propagation and Failure of Liquid-Filled Cylindrical Shells Damaged in High-Pressure Environments

Cylindrical shell structures have excellent structural properties and load-bearing capacities in fields such as aerospace, marine engineering, and nuclear power. However, under high-pressure conditions, cylindrical shells are prone to cracking due to impact, corrosion, and fatigue, leading to a reduction in structural strength or failure. This paper proposes a static modeling method for damaged liquid-filled cylindrical shells based on the extended finite element method (XFEM). It investigated the impact of different initial crack angles on the crack propagation path and failure process of liquid-filled cylindrical shells, overcoming the difficulties of accurately simulating stress concentration at crack tips and discontinuities in the propagation path encountered in traditional finite element methods. Additionally, based on fluid‒structure interaction theory, a dynamic model for damaged liquid-filled cylindrical shells was established, analyzing the changes in pressure and flow state of the fluid during crack propagation. Experimental results showed that although the initial crack angle had a slight effect on the crack propagation path, the crack ultimately extended along both sides of the main axis of the cylindrical shell. When the initial crack angle was 0°, the crack propagation path was more likely to form a through-crack, with the highest penetration rate, whereas when the initial crack angle was 75°, the crack propagation speed was slower. After fluid entered the cylindrical shell, it spurted along the crack propagation path, forming a wave crest at the initial ejection position.

Ventilatory response of peripheral chemoreceptors to hypercapnia during exercise above the respiratory compensation point.

Peripheral hypercapnic chemosensitivity (PHC) is assessed as the change in ventilation in response to a rapid change in carbon dioxide pressures (PCO2). The increase in chemoresponse from rest to sub-respiratory compensation point (RCP) exercise intensities is well-defined but less clear at intensities above the RCP when changes in known ventilatory stimulants occur. Twenty healthy subjects (n=10 females) completed a maximal exercise test on one day and on a subsequent day, transient hypercapnia was used to test PHC at multiple exercise stages. The transient hypercapnia involved two breaths of 10% CO2 repeated five times during each of the following: sitting at rest on the cycle ergometer, cycling at 40% Wmax, cycling at 85% Wmax, at rest on the cycle ergometer immediately following the 85% stage, and cycling at 40% Wmax again following the post-exercise rest. The PHC was not different across exercise intensities (0.98±0.37 vs. 0.91±0.39 vs. 0.92±0.42 L min-1 mmHg-1 for 1st 40% Wmax, 85% Wmax, and 2nd 40% Wmax, respectively (p=0.45). There were no differences in PHC between pre-supra-RCP exercise rest and post-supra-RCP exercise rest (0.52±0.23 vs. 0.53±0.24 L min-1 mmHg-1, p=0.8003). Using a repeated measures correlation to account for within participants changes, there was a significant relationship between the end-tidal PCO2 and PHC for the 85% intensity (r=0.5, p<0.0001) when end-tidal PCO2 was dynamic between the trials. We conclude that the physiological changes (e.g. metabolic milieu, temperature, etc) produced with supra-RCP exercise do not further augment PHC, and that the pre-stimulus end-tidal PCO2 modulates the PHC.

Associations of prenatal blood pressure trajectory and variability with child neurodevelopment at 2 years old

BackgroundThe patterns of blood pressure (BP) change throughout the pregnancy were related to adverse birth outcomes. However, little is known about the long-term effect of BP change patterns on child neurodevelopment. This study aimed to explore the relationship between the BP trajectory and BP variability during pregnancy and early childhood neurodevelopment.MethodA total of 2797 mother-newborn pairs were derived from the Wuhan Healthy Baby Cohort Study. BP was measured during each antenatal visit, and Mental and Psychomotor Development Indexes (MDI and PDI) were assessed using the Bayley Scales of Infant Development (BSID) when the children were 2 years old. Delayed neurodevelopment was defined as scores of PDI or MDI less than − 1SD relative to the mean score of the study population. A group-based multi-trajectory model was adopted to identify multi-trajectories of systolic blood pressure (SBP) and diastolic blood pressure (DBP). Visit-to-visit BP variability was assessed by the coefficient of variation (CV), standard deviation (SD), and average real variability (ARV). Generalized linear models and multivariate logistic regressions were used to assess the associations of BP trajectories and variability with BSID scores and delayed neurodevelopment, respectively.ResultsFive distinct trajectories for SBP and DBP were identified, namely, “Low-increasing,” “Low-stable,” “Moderate-decreasing,” “Moderate-increasing,” and “High-stable” groups. Compared with the “Low-stable” group, the children whose mothers’ BP fell into the other four groups had lower PDI scores, and mothers in the “Low-increasing,” “Moderate-increasing,” and “Moderate-decreasing” groups had 43% (OR: 1.43, 95% CI: 1.01, 2.03), 48% (OR: 1.48, 95% CI: 1.05, 2.08) and 45% (OR:1.45, 95% CI: 1.03, 2.04) higher risk of having offspring with delayed psychomotor neurodevelopment, respectively. High DBP variability was associated with lower BSID scores, and delayed psychomotor neurodevelopment (OR = 1.46, 95% CI: 1.10, 1.92 for DBP-SD; OR = 1.53, 95% CI: 1.16, 2.02 for DBP-CV).ConclusionOur findings suggest that BP change patterns assessed by multi-trajectory and visit-to-visit variability were associated with lower BSID scores and delayed neurodevelopment. Health professionals should be aware of the influence of BP level and its oscillations during pregnancy on the risk of delayed neurodevelopment.

Associations of Anxiety Symptoms With 6-Year Blood Pressure Changes and Incident Hypertension: Results From the Hispanic Community Health Study/Study of Latinos.

Despite the high burden of anxiety and hypertension in Hispanic/Latino adults, little is known about their association in this population. To examine the associations of anxiety symptoms with 6-year changes in blood pressure (BP) and incident hypertension in Hispanic/Latino adults. We examined data from a probability sample of 10,881 Hispanic/Latino persons aged 18-74 who attended visits 1 (V1; 2008-2011) and 2 (V2; 2014-2017) of the Hispanic Community Health Study/Study of Latinos (HCHS/SOL), a prospective cohort study. Anxiety symptoms were assessed at V1 using the 10-item Spielberger Trait Anxiety Scale (M = 17.1; Range = 10-40) and dichotomized using a cut-point of 20, the highest quartile in this cohort. BP was measured at both visits using a standardized protocol. Adults with elevated anxiety symptoms had a 1.02 mm Hg greater increase in systolic (p = .02) and a 0.75 mm Hg greater increase in diastolic BP (p = .02) over 6.1 years than those with lower symptoms, after adjusting for sociodemographic and clinical covariates. These associations differed by sex. Elevated anxiety was associated with a greater increase in systolic and diastolic BP in men only. Among persons without hypertension at V1 (N = 7,412), those with elevated anxiety symptoms at V1 had a 22% higher incidence of hypertension (p = .02) 6.1 years later. Our findings underscore the importance of screening for and treating elevated anxiety symptoms to help prevent hypertension. Further research on the role of sex and underlying mechanisms is warranted.