Adjustment For Pressure Research Articles

Impact of abdominal compliance on surgical stress and postoperative recovery in laparoscopic groin hernia repair: a retrospective cohort study

PurposeThe role of abdominal compliance in pneumoperitoneum is not fully understood. This study aimed to clarify the association between abdominal wall stretching tendency and surgical stress in laparoscopic groin hernia repair.MethodsWe conducted a retrospective single-center cohort study, evaluating 51 patients who underwent elective transabdominal preperitoneal groin hernia repair. Abdominal compliance was assessed using the abdominal compliance index (ACI; insufflated intra-abdominal volume [L] / body surface area [m²]) at 8 mmHg intra-abdominal pressure. Surgical stress and recovery were evaluated with patient-reported outcome measures (PROMs), including QOR-15 and pain visual analog scale (VAS) scores. Associations between ACI, PROMs, and clinical outcomes were analyzed.ResultsThe median ACI was 1.229 L/m² (0.369–2.091). Eleven patients (21.6%) above the 75th percentile cutoff (1.576 L/m²) were categorized as high ACI. While body constitution was similar between groups, the high ACI group had significantly greater insufflated intra-abdominal volume (2.88 L vs. 1.89 L, P < 0.0001). Pre-operative QOR-15 scores were similar. However, on postoperative day 1, the high ACI group had significantly lower QOR-15 scores (90.2 vs. 110.1, P = 0.017), with subcategory analysis showing reduced physical well-being. Multivariate analysis indicated that high ACI was a significant predictor of poorer QOR. The high ACI group also reported higher, though not statistically significant, postoperative pain.ConclusionAbdominal walls with greater elasticity, which stretch excessively under pneumoperitoneum, were more susceptible to surgical stress. Further studies are warranted to evaluate the efficacy of tailored pneumoperitoneum pressure adjustment based on abdominal compliance to mitigate surgical stress.

Changes of endotracheal tube cuff pressure and its indicators in laparoscopic resection of colorectal neoplasms: an observational prospective clinical trial

BackgroundLaparoscopic surgery is a popular alternative for resection of colorectal neoplasms. Carbon dioxide pneumoperitoneum and Trendelenburg positioning in procedure can significantly increase airway pressure, when endotracheal tube cuff pressure is not monitored. This prospective observational study aimed to evaluate indicators, changes and its correlation factors of endotracheal tube cuff pressure during laparoscopic resection of colorectal neoplasms.Methods122 patients scheduled for laparoscopic resection of colorectal neoplasms under propofol/remifentanil total intravenous anesthesia with orotracheal intubation were included. Tracheal tube cuff pressure was monitored continuously by calibrated pressure transducers. The ability of several predictors to predict out-of-range tracheal tube cuff pressure at different time points and its correlation factors were assessed.ResultsROC analysis showed that waist-to-hip ratio has the highest AUC for predicting out-of-range tracheal cuff pressure (AUC: 0.86 [95% CI: 0.77–0.95]); Tracheal tube cuff pressure provided by palpation was 41.0 (29.0−53.3) cmH20. Cuff pressure was 33.7 ± 2.9 cmH20 at 15 min and comparable at 30 and 45 min after insufflation, all values were significantly higher than 25 cmH20 (p < 0.001). Multiple linear regression showed tracheal tube cuff pressure was associated with peak airway pressure (p < 0.001).ConclusionsPatients with normal BMI undergoing laparoscopic resection of colorectal neoplasms require continuous monitoring and timely adjustments of tracheal tube cuff pressure. Compared with BMI, waist-to-hip ratio is a better predictor of out-of-range tracheal tube cuff pressure.Trial registrationChinese Clinical Trial Registry, identifier: ChiCTR2100054089, Date: 08/12/2021.

A cluster randomized trial on inspiratory effort-targeted pressure support adjustment strategy in patients undergoing assisted mechanical ventilation: protocol for the IT-PSV study.

Pressure support ventilation (PSV) is one of the most frequently used ventilator modes in the intensive care unit (ICU). The successful implementation of PSV depends on matching the patient's inspiratory effort with the ventilator support. In clinical practice, the pressure support level is usually set and adjusted according to tidal volume and respiratory rate. However, these parameters may not fully represent the patient's effort. Previous studies have shown that pressure muscle index (PMI), which is measured as the difference between the peak and plateau airway pressure during an end-inspiratory airway occlusion, could reliably determine the low and high inspiratory effort during PSV. Herein we present the study protocol for the Inspiratory effort-Targeted Pressure Support Ventilation (IT-PSV) trial to determine the effect of a PMI-targeted pressure support setting strategy on clinical outcomes in patients undergoing PSV. This is a cluster randomized controlled trial. Sixteen ICUs in academic hospitals will be included, eight of which will be randomly allocated to the PMI-targeted group and eight to the tidal volume/respiratory rate-targeted group. Before the initiation of the study, a four-week comprehensive training program, which includes courses of PSV initiation, pressure support adjustment, and weaning process, will be conducted for all staff in the participating ICUs. Adult patients with acute hypoxic respiratory failure and undergoing PSV within 24 h will be included. Pressure support setting and adjustment will follow the strategy according to the grouping. The primary outcome is the ventilator-free days at 28 days after enrollment. The patients will be followed up until successful weaning or separation of mechanical ventilation, death, hospital discharge, or until 28 days after randomization, whichever comes first. The IT-PSV trial will examine the effect of an inspiratory effort-targeted PSV setting strategy on the duration of mechanical ventilation. If positive, it will provide a new physiological-based PSV management that could potentially facilitate protective assisted ventilation. ClinicalTrials.gov, identifier NCT06526598.

Deployment dynamics of fluidic origami tubular structures

The application of origami in engineering has offered innovative solutions for deployable structures, such as in space exploration, civil construction, robotics, and medical devices, due to its ability to enable compact folding and expansive deployment. Despite its great potential, prior studies have predominantly focused on the static or kinematic aspects of the origami, leaving the dynamic deployment behaviors underexplored. This research addresses this gap by, for the first time, investigating the dynamics of deployment of origami tubular structures actuated by fluidic pressure induced by air or liquids. We introduce a novel dynamic model that incorporates and combines panel inertia and elastic properties, critical for capturing the complex behaviors of origami deployment that rigid kinematic models overlook, as well as the fluidic pressure effects on the structural mechanics and dynamics. Our findings, derived from non-dimensionalized models, reveal the profound influences of the structural and input parameters on the dynamic responses, marking a significant new advancement in origami research. Our study on fluidic origami tubes, where internal pressure is varied, uncovers how the pressurization level and rate affect the transient dynamics and final configuration of the system. The introduction of a space-invariant fluidic pressure, applied as either a step or ramp function, demonstrates the system's sensitivity to pressure adjustments, affecting its stiffness, damping ratio, and transient response. This feature leads to a rich multistability landscape, offering the ability to achieve various stable configurations through input pressure control, and uncovering unique dynamic responses such as snap-through and snap-back actions that have not been observed in the past. All these outcomes and insights are especially valuable in raising awareness of nontraditional behaviors and expanding our comfort zone in origami engineering.Overall, the research efforts not only propel new understanding of pressure actuated tubular origami's dynamic behaviors but also lay a novel foundational framework for developing origami-based systems for a wide array of applications, which will greatly enhance the design and operational possibilities of reconfigurable and deployable adaptive structures.

Quantitative analysis of pressure levels in manual lymphatic drainage across stages of breast cancer-related lymphedema: implications for optimized treatment protocols.

To quantify the pressure levels necessary for effective Manual Lymphatic Drainage (MLD) in managing Breast Cancer-Related Lymphedema (BCRL) across various stages, and to contribute to the development of standardized protocols for MLD therapy. The study included 42 patients with BCRL (Stages I-III) and 14 certified lymphedema therapists. Forearms and upper arm circumferences were measured pre and post a 21-day MLD intervention. A tactile sensor system recorded the applied pressure during treatment. The data were preprocessed and statistically analyzed to assess pressure patterns and their stage-specific impacts on lymphedema. The mean age of the patients was 52.4years, and that of the therapists was 39.1years. A statistically significant reduction in arm circumference was observed post-MLD treatment (P < 0.05). The pressure applied varied across stages: I forearm 16.5-20.1mmHg, I upper arm 16.1-20.7mmHg; II forearm 16.6-19.8mmHg, II upper arm 19.7-23.8mmHg; III forearm 29.3-34.3mmHg, III upper arm 29.7-34.3mmHg. No statistically significant difference was found between forearm and upper arm treatment pressures within Stages I (P = 0.283) and III (P = 0.08), while Stage II exhibited a significant difference (P < 0.001). Across the same treatment area, pressures for Stages I and II in the forearm were significantly lower than those in Stage III (P < 0.001). The treatment pressure differences between forearm stages I and II were not statistically significant (P > 0.05). Differences in upper arm treatment pressures across Stages I, II, and III were also statistically significant (P < 0.001). The study provides quantitative evidence on the pressure ranges needed for MLD across different stages of BCRL. It highlights the importance for stage-specific pressure adjustments to optimize treatment outcomes. These findings contribute to the existing body of knowledge on MLD and offer valuable data that could inform the development of rehabilitation technologies, including intelligent robots and visualization systems, as well as enhance therapist training programs.

Extraction of rhodium from supported liquid-phase hydroformylation catalysts with supercritical carbon dioxide

The continuous extraction of the rhodium inventory in supported liquid-phase (SLP) catalytic materials utilized in the hydroformylation (HyFo) of 1-butene was investigated by supercritical carbon dioxide (scCO2). Optimization of extraction efficiency involved varying parameters such as temperature (90 and 120 °C), pressure (10, 20 and 30 MPa), and the addition of methanol as a polar co-feed to the extraction medium (0–20 vol%). The results underscored the critical role of methanol in facilitating extraction, as experiments employing pure scCO2 yielded no rhodium recovery. Furthermore, extraction performance demonstrated sensitivity to temperature and pressure adjustments during the process. Notably, the use of 10 vol% methanol at 120 °C and 30 MPa achieved complete rhodium extraction from the grained SLP materials, which was identified as the optimum extraction condition. This study highlights the potential for scaling up in-situ rhodium extraction processes within HyFo production plants based on SLP catalysts, emphasizing significant implications for industrial applications.

Adaptive control of airway pressure during the expectoration process in a cough assist system.

Existing Mechanical Insufflation-Exsufflation (MI-E) devices often overlook the impact of cough airflow pressure on mucus clearance, particularly lacking in control over airway pressure during the expiratory phase, which can lead to airway collapse and other types of airway damage. This study optimizes the design of cough assist system and explores the effectiveness of PID and adaptive control methods in regulating airway pressure. The adaptive control method compensates for hose pressure drop by online estimation of the ventilatory hose characteristics. It achieves precise tracking of target pressure and ensures the generation of peak flow rates effective for mucus clearance, even in the absence of known patient lung physiological states and unknown hose leakage parameters. Through a series of comparative experiments, this paper confirms the significant advantages of adaptive control in reducing oscillations and overshoot, capable of more stable and precise airway pressure adjustments. This improved control strategy not only enhances clinical safety but also significantly improves therapeutic outcomes and reduces the risk of complications. The findings indicate that the revamped cough assist system, employing an adaptive control strategy, can effectively prevent airway damage during assisted coughing, offering a safer and more effective sputum clearance solution for critically ill patients with expectoration disorders.

Elevated Blood Pressure and Culprit Aneurysm Rebleeding During the Unsecured Period of Aneurysmal Subarachnoid Hemorrhage: A Systematic Review.

In aneurysmal subarachnoid hemorrhage, rebleeding prior to securing the culprit aneurysm leads to significant morbidity and mortality. Elevated blood pressure has been identified as a possible risk factor. In this systematic review, we evaluated the association between elevated blood pressure and aneurysm rebleeding during the unsecured period. We searched MEDLINE, Embase + Embase Classic, and CENTRAL, from inception to March 8th, 2024. We included studies of adults with aneurysmal subarachnoid hemorrhage reporting at least one blood pressure measurement during the unsecured period and a measure of association with rebleeding. Results were stratified by blood pressure thresholds, effect measure, and adjustment for confounding. Separate meta-analyses were performed for each of these groups. Our search identified 5,209 citations. After screening, 15 studies were included in our review. All studies were observational in design and at moderate or high risk of bias. Meta-analysis of the unadjusted results produced mixed findings across the systolic blood pressure (SBP) thresholds: SBP > 140mmHg, unadjusted odds ratio (uOR) 1.03 (95% confidence interval [CI] 0.55-1.93; I2 = 66%); SBP > 160mmHg, uOR 3.35 (95% CI 1.44-7.81; I2 = 83%); SBP > 180mmHg, uOR 1.52 (95% CI 0.40-5.81; I2 = 89%); and SBP > 200mm Hg, uOR 7.99 (95% CI 3.60-17.72; I2 = 0%). Meta-analysis of adjusted results was only possible at an SBP > 160mmHg; adjusted hazard ratio 1.13 (95% CI 0.98-1.31; I2 = 0%). The overall quality of evidence as assessed by the Grading of Recommendations, Assessment, Development, and Evaluations tool was rated as very low. Based on very low quality evidence, our systematic review failed to determine whether there is an association between elevated blood pressure during the unsecured period and increased risk of culprit aneurysm rebleeding.

Influence of back pressure adjustment of porous media on cavity flow noise control

Control of self-sustained oscillation and noise reduction poses a significant challenge. The present study employs Implicit Large Eddy Simulation at a Mach number of 0.85 to investigate the influence of a porous cavity floor on flow dynamics. By substituting the solid floor with porous media, the fundamental pressure–velocity relationship within the medium is established according to Darcy's law. Findings reveal marked suppression of wall pulsations, accompanied by a 10 dB decrease in sound pressure levels. The porous medium induces blowing and suction effects, effectively modulating large-scale re-circulation and mitigating shear layer instability, thereby approximating free mixing layer characteristics and suppressing cavity flow oscillations. At an optimized porosity for maximum noise reduction, altering back pressure at the cavity floor induces a transition in the local flow regime from suction-dominated to blowing-dominated state. Excessive reduction of back pressure promotes suction; conversely, increased pressure intensifies blowing, further attenuating feedback mechanisms and enhancing noise reduction. To explore noise reduction mechanisms, mode decomposition analyses demonstrate the efficacy of porous media in disrupting large-scale coherence structures within shear layer and redistributing energy from dominant modes to a broader frequency spectrum that engages smaller flow structures. This energy reallocation mechanism contributes to the mitigation of cavity flow noise and deepens insights into the role of porous media in flow modulation and noise control.

Influence of Processing Parameters in Injection Molding on the Properties of Short Carbon and Glass Fiber Reinforced Polypropylene Composites

Short-fiber reinforcement is a potent approach to improving the material properties of injection-molded parts. The main consideration in such reinforced materials is to preserve the fiber length, as this is the major influence on the properties of a given composite. The aim of this work was to investigate the different influencing parameters in injection molding processing on the properties of short carbon and glass fiber-reinforced polypropylene. We investigated parameters like melt temperature and back pressure, but also machine size and pre-heating regarding their influence on the tensile properties. We found that adjustments of melt temperature and back pressure only yield small improvements in the fiber length and the tensile properties, also depending on machine size, but a pre-heating step of the granules can significantly improve the properties.

A multi-mode self-centering piezo actuator: design, analysis and its application in full-stroke microscopic imaging

Parasitic piezo dive is a primary method for cross-scale positioning, which can adjust the locking force appropriately to increase the service life but bring radial fluctuations, backward motion, and bi-directional inconsistency issues. In this work, a multi-mode self-centering piezo actuator is proposed, a theoretical analysis model of the transmission mechanism is established, and parameterized design is conducted using the finite element method. The actuator features normal pressure adjustment, parallel drive, parasitic drive, and rectangular drive modes. Under the first mode, a bias voltage of 50 Vp-p achieved a locking force adjustment of 2.5 N. Furthermore, the characteristics of the remaining modes were compared. It was observed that the parallel trajectory drive mode exhibited a higher velocity of 31.68 mm/s, while the rectangular trajectory drive mode suppressed the backward motion to achieve smooth driving, with a linear correlation coefficient R2 of the displacement reaching 0.9999. Compared to the traditional parasitic actuator, the radial fluctuations in these two drive modes were reduced by up to 98.4 %, and the bidirectional consistency were improved to 97 %. Finally, we completed convenient imaging of various specimens across the full-stroke of microscopes by integrated circuit design and Bluetooth communication on mobile phones.

Optimized strategies for efficient CO2 trapping using hydrate technology by pressure adjustment

The hydrate-based method enhances oceanic CO2 storage capacity and is deemed beneficial for controlling greenhouse gas emissions. However, the non-uniform CO2 hydrate crystal interface in the sub-seabed storage layer acts as a barrier, slowing down mass transfer kinetics. This work employed in-situ nuclear magnetic resonance (NMR) technology to compare three different pressure adjustment strategies and observe CO2 bubble dispersion after hydrate dissociation, secondary nucleation, and crystal growth mechanism, along with pore water changes. The presence of micro/nano CO2 bubbles with high internal pressure and high specific surface area in the dissociation liquid significantly accelerated secondary micro-structural phase transition rates. The optimal hydrate-based CO2 storage efficiency reached up to 81.7 %. Moreover, the secondary formation of CO2 hydrates distributed more uniformly within the large, medium, and small pores and led to a significantly increased residual water conversion rate (reaching up to 88 %) in medium pores. The post-secondary formation of high-density hydrates resulted in low fluid mobility (T1/T2 mostly distributed in the range of 0 ∼ 10) and exhibited a mixed wettability state between pore fluids. Utilizing the “memory effects” of CO2 hydrate effectively overcame late-stage mass transfer barriers of solid hydrates films. Our findings extend the understanding of CO2 hydrate formation kinetics under pressure adjustment strategies.

Orthostatic hypotension and cerebral small vessel disease: A systematic review.

Orthostatic hypotension(OH) is highly prevalent in ageing populations and may contribute to cognitive decline through cerebral small vessel disease(CSVD). Research on the association between OH and CSVD is fragmented and inconsistent. We systematically reviewed the literature for studies assessing the association between OH and CSVD, published until December 1st 2023 in MEDLINE, PubMed or Web of Science. We included studies with populations aged ≥60, that assessed OH in relation to CSVD including white matter hyperintensities(WMH), lacunes and cerebral microbleeds. Modified JBI checklist was used to assess risk of bias. A narrative synthesis of the results was presented. Of 3180 identified studies, eighteen were included. Fifteen studies reported on WMH, four on lacunes, seven on microbleeds. Six of fifteen studies on WMH found that OH was related to an increased burden of WMH, neither longitudinal studies found associations with WMH progression. Findings were inconsistent across studies concerning lacunes and microbleeds. Across outcomes, adequate adjustment for systolic blood pressure tended to coincide with smaller effect estimates. Current evidence on the OH-CSVD association originates mostly from cross-sectional studies, providing inconsistent and inconclusive results. Longitudinal studies using standardized and fine-grained assessment of OH and CSVD and adequate adjustment for supine blood pressure are warranted.

Laboratory systems for detonation research

Decarbonizing global energy systems is among the most pertinent challenges in the climate crisis. Tightly tied to the economic prosperity of a nation and responsible for more than 75% of global emissions, decarbonization of the energy sector will require well-developed solutions. The emergence of detonation engines can reduce emissions in aviation and gas-fired power generation, with theoretical efficiencies 40% lower than conventional engines. These efficiencies have yet to be realized in practice, due to our lack of understanding of detonation propagation and its instabilities. This project aimed to develop the laboratory systems required to study detonations. To this end, a long rectangular channel was manufactured and outfitted with a gas handling system to inject a mixture, an ignition system, pressure transducers to capture the propagation characteristics, and an optical system enabling Schlieren photography. The gas handling system uses sonic nozzles, thus flow rate is a linear function of upstream line pressure. Each line contains a pressure transducer, microcontroller to process signals, LCD for pressure readout, and a regulator for adjustment of the line pressure. The ignition system uses an ignition box that steps up a 12 V supply to 400 V, an ignition coil raising the voltage to 15-40 kV, and a spark plug to ignite the mixture. Ignition, pressure transducer signal acquisition, and Schlieren photography are all synchronized using a NI-6356 DAQ with LabVIEW. The DAQs analog input ports receive readings from the pressure transducers along the channel, the timing of which and known distance between transducers allows for velocity calculations. The schlieren system utilizes the digital output channels to synchronize camera shutter with an LED driver, and parabolic mirrors, positioned to optimize schlieren imaging. The LED driver requires greater current than produced by the DAQ thus a current amplifier circuit is used to bridge the DAQ and driver.

Effect of different patient positions on endotracheal tube cuff pressure in patients undergoing urological procedures: a prospective study.

The endotracheal tube (ETT) contains a cuff that is placed in the trachea to prevent gas leakage and aspiration of secretions and gastric contents. However, patient positioning after intubation may cause ETT displacement and changes in cuff pressure. Evaluate the effect of different patient positions on ETT cuff pressure in patients undergoing urological procedures in supine, prone, lateral flank, and lithotomy positions. Prospective and observational study. A university hospital in Turkey. Patients who underwent surgeries under general anesthesia in different patient positions were involved. After intubation (T0), the cuff pressure was checked with a manometer and adjusted to 25 cmH2O and continuously monitored. The cuff pressure was checked before (T1) and after achieving the final position (T2) and then at 5, (T3), 10, (T4), 15 minutes (T5) of the position, at the end of the procedure (T6) and before extubation (T7). At postoperative 2nd and 12th hours, the patients were interviewed for sore throat, hoarseness, and cough. The effect of different patient positions on the ETT cuff pressure. 200 patients. The cuff pressure increased significantly at T2 in the lithotomy, lateral flank, and prone groups (P<.001 each). The highest increase in cuff pressure occurred in the prone group (34.3 [7.5] cmH2O). Over time, the cuff pressure decreased in all groups during surgery. Postoperative complications at the 2nd postoperative hour were similar in all groups; however, the mean cuff pressure was significantly higher in the patients with postoperative sore throat or cough (sore throat: P=.003; cough: P=.047). ETT cuff pressures are affected by different patient positioning; therefore, regular recording and adjustment of cuff pressure are necessary for patient safety. We used ETT of a single manufacturer. Therefore, our findings may not be applicable to other types of ETT.

O107 A LONGITUDINAL STUDY ON THE IMPACT OF CHILDHOOD ELEVATED BLOOD PRESSURE ON TARGET ORGAN HEALTH IN ADOLESCENCE: THE EXAMIN YOUTH SA STUDY

Background and objective: Primary hypertension in children is becoming a global threat for the growing economic burden of hypertension management in adulthood and sustainable healthcare. We determined the associations of adolescent blood pressure (BP) with target organ damage markers (carotid intima-media thickness (CIMT) and left ventricular mass index (ilVM)) over a four year period, stratified by childhood BP status at baseline. Methods: We included 421 Black and 307 White South African adolescents (mean age: 11.04 years) with complete follow-up data for BP, CIMT and iLVM. Standard anthropometric measures and basic demographic information were collected. Results: Children were stratified by baseline BP status, i.e., normotensive; n=454 (57.5% Black and 57.7% female) and elevated BP; n=274 (58.4% Black and 52.2% female), with comparable proportions of ethnicity (p=0.81) and sex (p=0.15). Systolic BP (by 6mmHg; p&lt;0.001), diastolic BP (by 3mmHg; p&lt;0.001) and perfusion pressure (by 4mmHg; p&lt;0.001) as well as sex-specific body mass index for age z-scores (BAZ; p&lt;0.001) were all higher in the elevated BP compared to normotensive group. Groups were comparable for age (p=0.78), CIMT (p=0.28) and iLVM (p=0.64). In partial regression analysis (adjusting for ethnicity, sex, follow-up age and BAZ), systolic BP correlated positively with CIMT (r=0.125; p=0.041) and iLVM (r=0.184; p=0.002) in the elevated BP group only. Backward multiple adjusted linear regression analysis (adjustment for perfusion pressure at baseline, age, sex, ethnicity and BAZ) showed adverse associations of systolic BP with CIMT (β=0.126; p=0.046) and iLVM (β=0.199; p=0.001), and diastolic BP with iLVM (β=0.130; p=0.002), only in children with elevated BP at baseline. Conclusion: Elevated BP in early childhood contributes to the long-term impact on target organ health during adolescence independent of sex and ethnicity, while the association of BP with iLVM seems to be moderated by excess adiposity.

A grey target performance evaluation model for aeroengine pressure test bench

PurposeThis paper aims to optimize the air pressure regulation scheme of the aeroengine pressure test bench.Design/methodology/approachBased on the requirements of pressure regulation process and the operating mechanism of aeroengine pressure test bench, a grey performance evaluation index system is constructed. The combination of principal component analysis and grey theory is employed to assign weights to grey indexes. The grey target evaluation model is introduced to evaluate the performance of historical regulation processes, and the evaluation results are analyzed to derive optimization mechanism for pressure regulating schemes.FindingsA case study based on monitoring data from nearly 300 regulation processes verifies the feasibility of the proposed method. On the one hand, the improved principal component analysis method can achieve rational weighting for grey indexes. On the other hand, the method comparison intuitively shows that the proposed method performs better.Originality/valueThe pressure test bench is a fundamental technical equipment in the aviation industry, serving the development and testing of aircraft engines. Due to the complex system composition, the pressure and flow adjustment of the test bench heavily rely on manual experience, leading to issues such as slow adjustment speed and insufficient accuracy. This paper proposes a performance evaluation method for the regulation process of pressure test bench, which can draw knowledge from historical regulation processes, provide guidance for the pressure regulation of test benches, and ultimately achieve the goal of reducing equipment operating costs.

Measurement of the water vapor transmission rate at temperatures above 100 °C

ABSTRACT Water vapor transmission rate (WVTR) and water vapor permeability coefficient were measured at temperatures between 110 and 138°C using the modified cup method. The cup, placed in a Highly Accelerated Stress Test chamber, allowed water vapor to permeate the sample film attached to the cup. The WVTR was determined based on the increase in mass of the cup. To prevent sample damage during measurement, a cup with a pressure adjustment mechanism was utilized. Carrier-incorporated phosphorus pentoxide was used as the desiccant instead of anhydrous calcium chloride to ensure a consistent moisture absorption rate, especially at high temperatures. The water vapor permeability coefficients for the polycarbonate, polyimide, and adhesive films were distributed on an approximately straight line in the Arrhenius plot. Additionally, the Arrhenius plots for the polyethylene terephthalate and polyethylene naphthalate films captured the permeability bending point near the glass transition temperature. To accurately measure the high-temperatureWVTR, upper and lower limits were established for the weighing interval, cup mass gain, and WVTR measurement range.

Racial Differences in Age-Related Changes in Left Ventricular Structural and Functional Echocardiographic Measurements Among Healthy Japanese and American Participants - A Subanalysis of the World Alliance Society of Echocardiography Normal Values Study.

Age-related changes in left ventricular (LV) structure and function lower the threshold for the onset of heart failure with preserved ejection fraction (HFpEF). LV parameters change also with race; however, the racial differences in age-related changes in LV parameters with and without adjustment for body mass index (BMI), heart rate (HR), and blood pressure (BP) remain unclear. We performed a subanalysis of the World Alliance Society of Echocardiography Normal Values Study, an international cross-sectional study that examined normal echocardiographic values in 15 countries. The age-related changes in 2-dimensional echocardiographic derived parameters including LV size, systolic function, and mass, were compared between healthy Japanese (n=227) and healthy White (n=98) and Black (n=69) American participants. In men, age-related changes in all parameters did not differ significantly among races. However, compared with Japanese women, White American women had a smaller body surface area (BSA)-indexed LV volume, BSA-indexed LV internal dimension at end-systole, BSA-indexed LV stroke volume, and LV mass index to BSA, and a larger LV ejection fraction with age, even after adjusting for BMI, HR, and BP. Age-related changes in LV structure and function, which are important for the pathophysiology of HFpEF, may differ by race. Therefore, future studies examining echocardiographic reference values for each age group in each race are needed.

Omitting the Escalating Dosage of Alpha-adrenergic Blockade Before Pheochromocytoma Resection: Implementation of a Treatment Strategy in Discordance With Current Guidelines.

This study describes the effects of introducing a protocol omitting preoperative α-blockade dose-escalation (de-escalation) in a prospective patient group. The decline of mortality and morbidity associated with pheochromocytoma resection is frequently attributed to the introduction of preoperative α-blockade. Current protocols require preoperative α-blockade dose-escalation and multiple-day hospital admissions. However, correlating evidence is lacking. Moreover, recent data suggest equal perioperative safety regardless of preoperative α-blockade escalation. Single-institution evaluation of protocol implementation, including patients who underwent adrenalectomy for pheochromocytoma between 2015 and 2023. Intraoperative hemodynamic control was regulated by active adjustment of blood pressure using vasoactive agents. The primary outcome was intraoperative hypertension, defined as the time-weighted average of systolic blood pressure (TWA-SBP) above 200mmHg. Secondary outcomes included perioperative hypotension, postoperative blood pressure support requirement, hospital stay duration, and complications. Of 102 pheochromocytoma patients, 82 were included; 44 in the de-escalated preoperative α-adrenergic protocol and 38 following the previous dose-escalation protocol. Median [IQR] TWA-SBP above 200mmHg was 0.01 [0.0-0.4]mmHg in the de-escalated group versus 0.0 [0.0-0.1]mmHg in the dose-escalated group ( P =0.073). The median duration of postoperative continuous norepinephrine administration was 0.3 hours [0.0-5.5] versus 5.1 hours [0.0-14.3], respectively ( P =0.003). Postoperative symptomatic hypotension occurred in 34.2% versus 9.1% of patients ( P =0.005). Median hospital stay was 2.5 days [1.9-3.6] versus 7.1 days [6.0-11.9] ( P <0.001). No significant differences in complication rates were observed. Our data suggest that adrenalectomy for pheochromocytoma employing a de-escalated preoperative α-blockade protocol is safe and results in a shorter hospital stay.