Pressure Resistance Research Articles

Study of the Correlation between Pressuremeter Limit Pressure and Dynamic Resistance obtained by the Dynamic Probing Super Heavy (DPSH) of the Sands of Lome in Togo

The design of building foundations relies on a good understanding of the bearing capacity of soils, which is determined by various in situ testing methods, such as pressuremeter and penetrometer tests. The pressuremeter test provides valuable information on the strength and deformability of soils at depth, while the dynamic cone penetrometer more easily assesses the dynamic resistance of the soil under dynamic loads. In this study, correlations were established between the dynamic resistance qd measured with the dynamic probing super heavy and the limit pressure pL obtained with the Menard pressuremeter. The data collected come from geotechnical investigations carried out on sandy soils of Lome in Togo. For these soils, the ratio is in the following interval: 8.27 ≤ qd/pL ≤ 9.74. Keywords: correlation, dynamic resistance, limit pressure, sand.

Evaluation of intestinal wall closure using vessel-sealing technology versus conventional closure: an in vivo study.

Anastomotic leakage is a major postoperative complication of colorectal surgery. LigaSure™ is used commonly for vessel-sealing, but its use for intestinal anastomosis or closure, particularly the healing process, is underreported. We conducted this study to evaluate the feasibility of using LigaSure™ for intestinal wall closure, compared with hand-sewn methods. We performed intestinal wall closure of the cecum in rat laparotomy procedures, dividing subjects into a LigaSure™ group (LS) and a hand-sewn group (HS). We compared operation times, tissue structure changes, and pressure resistance from immediately post-operatively to postoperative day (POD) 14. No postoperative dehiscence or mortality occurred in either group. The LS group required significantly less closure time (113s) than the HS group (321 s, p < 0.001). The adhesion rates for a midline incision were not significantly different between the groups (LS: 26.7% vs. HS: 6.7%; p = 0.142), with adhesions at the closure site seen in all subjects. The LS group had a lower burst pressure than the HS group until POD 3, with no significant differences thereafter. Structural continuity was established by POD 5 in both groups. LigaSure™ provides effective intestinal wall closure with a more distinct healing process than with hand-sewn methods, suggesting the potential for staple-free anastomosis.

Superhydrophobicity With Self-Adaptive Water Pressure Resistance and Adhesion of Pistia Stratiotes Leaf.

Superhydrophobic surfaces are promising for optimizing amphibious aircraft by minimizing water drag and adhesion. Achieving this involves ensuring these surfaces can resist high liquid pressure caused by deep water and fluid flow. Maximizing the solid-liquid contact area is a common strategy to improve liquid pressure resistance. However, this approach inevitably increases solid-liquid adhesion, making it challenging to guarantee a trade-off between the two wetting characteristics. Here, it is found that the Pistia stratiotes leaf exhibits superhydrophobicity with high water pressure resistance and low adhesion, attributed to its self-adaptive deformable microstructure with unique re-entrant features. Under pressure, these microstructures deform to increase the solid-liquid contact area, thereby enhancing water pressure resistance. The re-entrant features elevate the deformation threshold, enabling higher modulus microstructures to achieve adaptive response. This facilitates the recovery of deformed microstructures, restoring the air layer and maintaining low adhesion. Following these concepts, Pistia stratiotes leaf-inspired surfaces are fabricated, achieving an 183% improvement in water impact resistance and an ≈80% reduction in adhesion after overpressure compared to conventional superhydrophobic surfaces. The design principles inspired by Pistia stratiotes promise significant advancements in amphibious aircraft and other trans-media vehicles.

Numerical and experimental study on the mechanism of added resistance in stepped moonpool under different waves

To study the additional resistance effect of the moonpool during the navigation of the drilling vessel, this paper explores the variation of the drilling vessel resistance under different waves based on a model test and numerical simulation. The difference between the model test and the numerical simulation results is compared, and the mechanism of the added resistance of the moonpool under different waves is revealed. The results show that the technology of numerical simulation is able to accurately simulate the navigation resistance of the drilling vessel in waves. The numerical simulation results closely correspond to the experiment results, and the error range can be controlled within 10%. In the components of the total resistance of the hull, pressure resistance plays a dominant role when the drilling vessel sails in waves. The pressure resistance accounts for about 60%–70% of the total resistance, while the friction resistance accounts for about 30%–40% of the total resistance. At low speed, the average resistance reduction rate of the dissipative equipment is 4.4%; under the condition of medium speed, it is 7.5%; at high speed, it is 9.6%; and the resistance reduction efficiency of the dissipative equipment increases with the increase in speed. The dissipative equipment partially suppresses the eddy's action stage and prevents eddy shedding from entering and directly hitting the back wall, thereby reducing the moonpool's additional pressure resistance. The research results can provide a reference for energy savings and emission reductions in drilling vessels.

Design and Characterization of a New Quartz Smog Chamber System for Studying the Atmospheric Effects of Vehicle Emissions on Plateaus

Since the 1960s, smog chambers have been an important tool for studying air pollution, and many indoor and outdoor smog chambers have been developed both domestically and internationally. However, all of these chambers are located at altitudes below 1500 meters, only simulating atmospheric conditions in low-altitude plains. Moreover, most are made of polytetrafluoroethylene (PTFE), resulting in a higher wall deposition effect. To simulate the evolution of atmospheric pollution in high-altitude regions, we developed the world's highest-altitude quartz smog chamber, located in Kunming at an elevation of 1900 meters. The chamber is a 3.375m³ cube constructed from 5mm quartz glass and features controlled temperature (0°C to 40°C) and relative humidity (2%-95%). We conducted a comprehensive characterization of the chamber, including tests for temperature and humidity stability, mixing stability, pressure resistance and sealing, light intensity measurement and environmental light matching, and background pollutant and wall loss assessments. The characterization results indicate excellent performance in simulating sunlight and controlling background pollutants. The NO2 photolysis rate is adjustable, ranging from 2.03×10⁻³s⁻1 to 5.87×10⁻³s⁻1. Under dry conditions, after 6 hours of photooxidation, the detected O3 formation rate was approximately 1.05 ppb/h, with a particulate mass concentration around 0.12 μg/m³. The reactor withstands pressures exceeding 1.5 bar, and at this pressure, the leak rate was measured at 1.1‰. Validation using the toluene-NO₂ system showed that indoor mixing reached equilibrium in about four minutes. The wall loss rate for SWFU-HAP particles at 25°C and RH <10% was 0.066 h⁻1, which is 70% lower compared to other chambers, while at RH = 50%, the wall loss rate was 0.137 h⁻1. These results demonstrate the superior performance of our system, meeting the high standards required for high-altitude vehicle exhaust aerosol emissions research and the investigation of the formation mechanisms of vehicle exhaust in high-altitude atmospheric environments.

Cardiovascular responses to experimental weight gain in humans: a feasibility study.

Obesity and hypertension share a well known association. However, the mechanisms underlying their relationship are not well understood. Our goal was to assess the feasibility of a longitudinal, interventional weight gain study with detailed cardiovascular measurements in humans. Sixteen healthy, normotensive, young, male volunteers (28 ± 7 years) were enrolled. Body composition, biochemical and cardiovascular data were obtained at baseline, and after an 8-week period of overfeeding (800-1000 kcal/day). Blood pressure (BP), cardiac output (CO) and peripheral vascular resistance (PVR) were determined, as were the minimum forearm vascular resistance (MFVR), forearm blood flow (FBF) response to mental stress and heart rate variability (HRV) parameters. Overfeeding resulted in a median weight gain of 5.6 kg [interquartile range (IQR) 4.6-6.4 kg; P < 0.001]. Seated systolic and diastolic BP were significantly increased by 10 ± 9 and 4 ± 6 mmHg, respectively, after weight gain ( P < 0.001 and P = 0.011, respectively). CO also increased and PVR decreased significantly as a result of weight gain ( P = 0.032 and P = 0.044, respectively). MFVR was also significantly decreased after weight gain ( P = 0.023). The FBF response to mental stress was blunted significantly ( P = 0.002), and sympathovagal balance and responsiveness to orthostatic challenge altered moderately after weight gain. Our overfeeding regimen resulted in moderate weight gain and significant increases in BP. An increase in CO is likely to be the dominant mechanism underlying the observed BP changes, with decreases in PVR partially compensating for these effects. Experimental weight gain, coupled with detailed cardiovascular phenotyping, is a feasible model to examine potential mechanisms underlying obesity-associated hypertension in young adults.

Research on the wind pressure resistance and fracture capacity of windshield glass for rail vehicles

Research on the wind pressure resistance and fracture capacity of windshield glass for rail vehicles

Estimation of Undrained Shear Strength of Soil from CPTu Data

The estimation of undrained shear strength ( ) from Cone Penetration Test with pore pressure measurement (CPTu) for two sites was investigated in this research. The CPTu cone parameters: net cone resistance ( ), excess pore pressure ( ) and effective cone resistance ( ) were used to estimate the for the two sites and the values obtained were compared with the undrained shear strength in triaxial compression ( calculated from Anisotropically Consolidated Undrained Compression (CAUC) triaxial test results. For the clayey silt site, the undrained shear strength from the CAUC tests are higher compared to the values obtained from the CPTu, and the highest correlation was obtained from the effective cone resistance parameter . For the quick clay test site, the value and were relatively the same and showed stronger correlation as compared to the clayey silt site. The measured from the cone parameter had the highest correlation. It was concluded that and yields good correlation with the CAUC results for the clayey silt and quick clay test sites respectively as compared to the other con parameters.

Physical pressure resistance of gastrointestinal anastomotic site via plate of polyglycolic acid promoting fibrosis

Anastomotic-leakage incidence has been reported to be reduced on using polyglycolic acid (PGA) sheets as reinforcing materials; however, there is insufficient evidence regarding the reinforcement mechanism. Therefore, we investigated effects of PGA sheets on gastrointestinal anastomoses in rats. In the first approach, five rats underwent laparotomy; the PGA sheet was pasted onto the normal cecal wall. After five days, the cecum was removed and histologically evaluated. In the second approach, ten rats were randomly divided into two groups of five animals each. The rats underwent laparotomy; the cecal wall was sutured after a full-thickness incision. In the PGA group, a PGA sheet was used to cover the suture area. After 5 days, the cecum was removed, and the physical pressure resistance was evaluated. We confirmed the growth of a fibrous capsule measuring 855 (648–1048) µm outside the cecal serosa in the first approach. The median pressure resistance in the second approach was 57.0 (45.0–90.0) and 90.0 (82.5–94.5) mmHg in Control and PGA groups, respectively. The pressure resistance was significantly higher in the PGA group (p = 0.046). In summary, the PGA sheet may form a barrier of fibrosis on the intestinal wall and provide reinforcement to prevent anastomotic leakage.

Echocardiographic profiles of patients with CPCPH and IPCPH in HFpEF: insights from the PHHF study

Abstract Background The 2022 ESC/ERS guidelines changed the definition of post-capillary pulmonary hypertension (pcPH) in heart failure (HF) by lowering the level of mean pulmonary arterial pressure (mPAP) and pulmonary vascular resistance (PVR). Yet, the echocardiographic profile of HF with preserved ejection fraction (PEF) patients according to their mPAP and RVP is not known. Objectives To investigate the echocardiographic profile of HFPEF patients according to their mPAP and RVP. Methods Stable HF patients with the need for right heart catheterization were enrolled from 2010 to 2018 and prospectively followed-up in this multicenter study. All patients had a right heart catheterization and an echocardiography within the 24 hours. PcPH was characterized by a pulmonary wedge pressure exceeding 20 mm Hg and mean mPAP greater than 20 mm Hg, from an isolated state when PVR was less than 2 Wood units (WU, IpcPH) to a combined form when PVR exceeded 2 WU (CpcPH). Results Out of 662 HF patients included in PHHF study, 268 (40%) were classified as having HFpEF (35% male, median age 71 yo). Compared to IpcPH patients, CpcPH patients had higher tricuspid regurgitation peak velocity (sPAP, 3.53 vs 3.00 m/s, p&amp;lt;0.01), lower S tricuspid tissue Doppler velocity (10 vs. 11 cm/s, p 0.01) and TAPSE (18 vs. 21 mm, p&amp;lt; 0.01) and lower TAPSE/sPAP ratio (0.3 vs. 0.4, p&amp;lt;0.01). There were no differences between groups regarding both right ventricle and right atrial diameter and area. Conclusion In HFpEF patients with PH, CpcPH patients had worse right ventricular function despite similar remodeling when compared to IpcPH patients

3D Vortex-Energetics in the Left Pulmonary Artery for Differentiating Pulmonary Arterial Hypertension and Pulmonary Venous Hypertension Groups Using 4D Flow MRI.

Pulmonary hypertension (PH) is a life-threatening. Differentiation pulmonary arterial hypertension (PAH) from pulmonary venous hypertension (PVH) is important due to distinct treatment protocols. Invasive right heart catheterization (RHC) remains the reference standard but noninvasive alternatives are needed. To evaluate 4D Flow MRI-derived 3D vortex energetics in the left pulmonary artery (LPA) for distinguishing PAH from PVH. Prospective case-control. Fourteen PAH patients (11 female) and 18 PVH patients (9 female) diagnosed from RHC, 23 healthy controls (9 female). 1.5 T; gradient recalled echo 4D flow and balanced steady-state free precession (bSSFP) cardiac cine sequences. LPA 3D vortex cores were identified using the lambda2 method. Peak vortex-contained kinetic energy (vortex-KE) and viscous energy loss (vortex-EL) were computed from 4D flow MRI. Left and right ventricular (LV, RV) stroke volume (LVSV, RVSV) and ejection fraction (LVEF, RVEF) were computed from bSSFP. In PH patients, mean pulmonary artery pressure (mPAP), pulmonary capillary wedge pressure (PCWR) and pulmonary vascular resistance (PVR) were determined from RHC. Mann-Whitney U test for group comparisons, Spearman's rho for correlations, logistic regression for identifying predictors of PAH vs. PVH and develop models, area under the receiver operating characteristic curve (AUC) for model performance. Significance was set at P < 0.05. PAH patients showed significantly lower vortex-KE (37.14 [14.68-78.52] vs. 76.48 [51.07-120.51]) and vortex-EL (9.93 [5.69-25.70] vs. 24.22 [12.20-32.01]) than PVH patients. The combined vortex-KE and LVEF model achieved an AUC of 0.89 for differentiating PAH from PVH. Vortex-EL showed significant negative correlations with mPAP (rho = -0.43), PCWP (rho = 0.37), PVR (rho = -0.64). In the PAH group, PVR was significantly negatively correlated with LPA vortex-KE (rho = -0.73) and vortex-EL (rho = -0.71), and vortex-KE significantly correlated with RVEF (rho = 0.69), RVSV, (rho = 0.70). In the PVH group, vortex-KE (rho = 0.52), vortex-EL significantly correlated with RVSV (rho = 0.58). These preliminary findings suggest that 4D flow MRI-derived LPA vortex energetics have potential to noninvasively differentiate PAH from PVH and correlate with invasive hemodynamic parameters. 1 TECHNICAL EFFICACY: Stage 3.

Parathyroid hormone exacerbates pulmonary hypertension via parathyroid hormone receptors on pulmonary artery smooth muscle cells

Abstract Background Pulmonary hypertension (PH) is a right heart failure disease and can be fatal. Parathyroid hormone (PTH) is a bone metabolism hormone and regulates calcium and phosphorus homeostasis. Previous studies have suggested that PTH affects the cardiovascular system and influences cardiovascular diseases. We hypothesized that PTH may play a role in the pathogenesis of PH. Purpose This study aimed to investigate whether PTH has a critical role in pulmonary hemodynamics. Method Serum PTH levels were measured in patients with PH or suspected PH undergoing right heart catheterization. We tested whether the regulation of PTH and the PTH receptor (PTH1R) affected PH in hypoxia (Hx)-induced PH model mice and Sugen/hypoxia (SuHx)-induced PH model ras. Hx mice were treated with PTH daily for 3 weeks or with an inhaled AAV-shRNA system to knockdown PTH1R expression in the lung. SuHx rats underwent parathyroidectomy (PTx). We measured physical data and right ventricular systolic pressure (RVSP) in these models. Human pulmonary artery smooth muscle cells (PASMCs) were cultured and treated with PTH to examine the direct effects of PTH. Result In the clinical study, we enrolled 30 participants and found serum PTH levels correlated with mean pulmonary artery pressure (r = 0.67) and pulmonary vascular resistance (r = 0.62). The ROC curve showed a cut-off PTH level of 46.0 pg/mL (68.2% sensitivity, 100% specificity) to predict PH. In animal models, PTH treatment exacerbated right ventricular hypertrophy and increased right ventricular systolic pressure (RVSP) in Hx mice compared with non-treated Hx mice (Figure 1). In contrast, knockdown of PTH1R in the lungs improved PH in Hx mice, and PTx significantly suppressed PH in SuHx rats (Figure 2). PTH promoted migration and proliferation through PTH receptor-ERK signaling in PASMCs. Conclusion Our clinical and experimental data showed that PTH exacerbates PH and suggest that PTH/PTH1R signaling would be a new target for PH treatment.

Left atrial strain demonstrates the ability to distinguish patients with pre and post-capillary pulmonary hypertension

Abstract Background The characterization of pulmonary hypertension (PH) patients into pre or postcapillary (pcPH)phenotypes poses a challenge during screening due to the ambiguity surrounding their comorbidities. This distinction is crucial as it influences treatment decisions and prognostication. Purpose Investigating Left Atrial Strain as a Discriminant Marker for Distinguishing Pre and Post-Capillary PH. Methods Out of 164 patients exhibiting both pre- and post-capillary phenotypes, 97 had optimal left atrial 2D strain. Left atrial 2D strain was performed with a GE Vivid9 ultrasound machine equipped with dedicated software, ensuring meticulous attention to image quality and region of interest thickness restricted to a maximum of 6 mm. Subsequently, the peak left atrial strain during reservoir function was quantified as part of the investigation. To determine the optimal cut-off value, ROC curve analysis was employed. Results 60 patients had pcPH while 37 had pre-capillary PH. Mean age was 65±12y. Mean pulmonary artery pressure, wedge pressure, cardiac output and pulmonary vascular resistance averaged 40,9±10,7 mm Hg, 15,7±8,7 mm Hg, 5,9±2,0 l/min and 4,7±3,1 WU, respectively. Left atrial 2D strain ranged from +2,5% to 60%, with a mean of +18,2±11,2%. From ROC cure analysis, patients with LA 2D strain &amp;gt; +19,1% had a precapillary phenotype with a sensitivity and a specifity of 93% and 88% respectively (Fig 1). Left atrial 2D strain demonstrates higher sensitivity compared to various parameters, such as scores from the European Society of Respiratory Disease, left ventricular end-diastolic pressure estimation from the American Society of Echocardiography, HFA-PEFF score, and H2FPEF from the AHA. Conclusion Left atrial 2D strain demonstrates superior sensitivity in distinguishing between patients with pre and post-capillary pulmonary hypertension compared to other assessment methods.FIG 1:Left atrial 2D strainFig 2:SENS of parameters and scores

TAPSE/sPAP by echocardiography to detect elevated pulmonary vascular resistance&amp;gt; 4 WU in postcapillary pulmonary hypertension patients: insights from the French PH HF registry

Abstract Background Post-capillary pulmonary hypertension (pcPH) lacks effective treatment options. Patients with a PVR &amp;gt; 4 WU, known as combined pcPH (cpcPH), may benefit from investigational drugs like sotatercept. Identifying cpcPH patients suitable for vasodilation therapy in echocardiography labs is critical. Purpose To pinpoint an echocardiographic parameter capable of detecting cpcPH patients with a PVR above 4WU, addressing a common challenge in clinical practice. Methods In this study, 225 participants from the French PH-HF registry, all diagnosed with heart failure and a preserved ejection fraction, were examined. These patients underwent right heart catheterization and got ultrasound examinations within a 24-hour timeframe. The pulmonary vascular resistance were calculated using previously established methods, and data from standard echocardiography, including assessments of diastolic function, were gathered. Results 69 patients exhibited a pulmonary vascular resistance (PVR) greater than 4 WU, while 156 patients had a PVR ≤ 4 WU. Age averaged 69±12 years. Mean pulmonary artery pressure, wedge pressure, cardiac output, and pulmonary vascular resistance were 39±9 mm Hg, 22±4 mm Hg, 5.1±1.7 l/min, and 3.5±2.0 WU, respectively. Comparative analysis between patients with PVR ≤ 4 WU and those with PVR &amp;gt; 4 WU revealed similar ejection fraction (EF), left atrial volume index, and E/A ratio by echocardiography (p=0.97, p=0.69, p=0.43, respectively). However, patients with PVR &amp;gt; 4 WU showed elevated E/e’ (p=0.008), higher systolic pulmonary artery pressure (sPAP, p=0.001), but reduced myocardial S and e’ tissue Doppler velocities (p=0.001) and tricuspid annular plane systolic excursion (TAPSE) (p=10^-5). Notably, the relationship between TAPSE/sPAP and PVR &amp;gt; 4 was curvilinear and strong (p=0.001, FIG 1). Using ROC curve analysis, patients with TAPSE/sPAP &amp;lt; 0.38 mm/mmHg were identified to have PVR &amp;gt; 4 WU with a sensitivity and specificity of 68%. Conclusion Within the scope of postcapillary pulmonary hypertension, right ventricular arterial coupling is a simple ultrasound parameter potentially effective in identifying individuals exhbiting PVR &amp;gt; 4 WU with a good sensitivityFigure 1:PRV and coupling plotFigure 2:RV coupling ROC

Effect of rPET Content and Preform Heating/Cooling Conditions in the Stretch Blow Molding Process on Microcavitation and Solid-State Post-Condensation of vPET-rPET Blend: Part I-Research Methodology and Results.

Polyethylene terephthalate (PET) is widely used in bottle production due to its cost-effectiveness and low environmental impact. The first part of this article describes the research and statistical analysis methodology of the influence of the virgin PET (vPET) and recycled PET (rPET) content in the vPET-rPET blend, as well as the preform heating/cooling conditions in the stretch blow molding (SBM) process on the microscopic bottle properties. Microscopic properties such as crystallinity, density, viscosity, relaxation degree of the amorphous phase, and microcavitation in PET were examined. This study reveals that microcavity and solid-state post-condensation effects occur during PET deformation in the SBM process. The increase in free volume, indicating microcavitation, was confirmed by measuring positron annihilation lifetime spectroscopy (PALS). PALS and density of the amorphous phase studies prove a reduction in the dimensions of the free volumes, with a simultaneous significant increase in their number and ellipsoidization. It can be associated with crystallite rotation in a temperature-dependent non-crystalline matrix. The occurrence of solid-state post-condensation effects was confirmed by measuring the intrinsic viscosity. The conclusions resulting from the analysis of the microstructure affecting the mechanical strength of the material were validated by pressure resistance tests of the bottles.

Origin of Pressure Resistance in Deep-Sea Lactate Dehydrogenase.

High hydrostatic pressure has a dramatic effect on biochemical systems, as exposure to high pressure can result in structural perturbations ranging from dissociation of protein complexes to complete denaturation. The deep ocean presents an interesting paradox since it is teeming with life despite the high-pressure environment. This is due to evolutionary adaptations in deep-sea organisms, such as amino acid substitutions in their proteins, which aid in resisting the denaturing effects of pressure. However, the physicochemical mechanism by which these substitutions can induce pressure resistance remains unknown. Here, we use molecular dynamics simulations to study pressure-adapted lactate dehydrogenase from the deep-sea abyssal grenadier (Coryphaenoides armatus), in comparison with that of the shallow-water Atlantic cod (Gadus morhua). We examined structural, thermodynamic and volumetric contributions to pressure resistance, and report that the amino acid substitutions result in a decrease in volume of the deep-sea protein accompanied by a decrease in thermodynamic stability of the native protein. Our simulations at high pressure also suggest that differences in compressibility may be important for understanding pressure resistance in deep-sea proteins.

IMPACT OF ADVANCED HEMODYNAMIC MONITORING ON MYOCARDIAL REVASCULARIZATION SURGERY IN HIGH-RISK PATIENTS

Coronary artery bypass grafting is a critical procedure for patients with advanced coronary disease, especially those classified as high risk due to comorbidities such as heart failure, hypertension and diabetes. Advanced hemodynamic monitoring has proved essential in this context, allowing continuous and accurate surveillance of cardiac and vascular parameters, which can reduce intra- and post-operative complications. This abstract aims to assess the impact of advanced hemodynamic monitoring during coronary artery bypass graft surgery in high-risk patients. The aim is to explore the advantages of this type of monitoring, the technologies used and the benefits in terms of clinical outcomes and reduction of complications. This is a literature review with a qualitative approach, carried out in the PubMed, SciELO, LILACS, BVS and Google Scholar databases. In order to optimize the search, descriptors such as Hemodynamic Monitoring, Cardiac Surgery, High Risk Patients and Fluid Management were used. For time delimitation, the research considered publications between the years 2019 and 2022, a period that reflects the latest advances in hemodynamic monitoring technologies in high-risk cardiac surgeries. Advanced hemodynamic monitoring includes the use of devices such as the pulmonary artery catheter and non-invasive bioimpedance systems, which provide real-time data on cardiac output, blood pressure, oxygen saturation and systemic vascular resistance. In high-risk patients, these devices allow for precise adjustments in the administration of fluids and vasoactive drugs, promoting better hemodynamic stability. Studies indicate that this approach reduces the incidence of serious complications, such as cardiogenic shock and arrhythmias, optimizing post-operative recovery. Therefore, advanced hemodynamic monitoring is a crucial tool in CABG surgeries, especially for high-risk patients. Its implementation improves intraoperative management, reducing the risk of complications and promoting better clinical outcomes. Therefore, its use should be considered an integral part of strategies for complex cardiac surgeries.

Durable Superhydrophobic Coatings with Attapulgite for Inhibiting 5G Radome Rain Attenuation.

5G radomes are easily wetted and stained by rainfall, which greatly reduces the quality of signal transmission. Superhydrophobic coatings are expected to solve this problem because of their unique wettability, but it is still challenging to develop robust superhydrophobic coatings via simple methods. Here, we report the design of robust superhydrophobic coatings containing oxalic acid-modified attapulgite (MDP) for inhibiting rain attenuation of 5G radomes. First, a homogeneous suspension was prepared by nonsolvent-induced phase separation of a silicone-modified polyester adhesive (SMPA) solution containing fluorinated MDP (F-MDP) nanorods. Superhydrophobic coatings can be easily prepared by spraying the suspension. The effects of phase separation and the SMPA/F-MDP ratio on the surface morphology, superhydrophobicity, and stability of the coatings were systematically investigated. The micro-/nanostructure and low surface energy endow the coatings with excellent static and dynamic superhydrophobicity. Compared with previous studies, the coatings exhibit excellent mechanical stability, flexibility, chemical stability, and pressure resistance due to the combined effects of adhesion by SMPA, self-similar micro-/nanostructures, reinforcement by the MDP nanorods, etc. Consequently, the coatings show good performance in preventing rain attenuation of 5G radomes, an emerging application of Superhydrophobic coatings. We believe that the coatings have great application potential in various fields, including 5G communication.

Enhancing barrier properties of cellulose propionate films through the integration of ionic liquid: A study on water pressure resistance

This study pioneers the production of porous cellulose propionate (CP) films enhanced with tetrabutylammonium styrenesulfonate ([N4444][SS]), an ionic liquid, to bolster their resistance against water pressure. In contrast to polymer films with ionic liquids that have high moisture permeability, the CP/[N4444][SS] films exhibit remarkable water resistance even under 8 bar pressure. This is due to the physical cross-linking between the [N4444] ions and CP's polar groups, limiting CP chain mobility and thus reducing water interaction. Fourier-transform infrared spectroscopy confirmed these interactions, while scanning electron microscopy revealed a dense, unconnected porous structure. Thermogravimetric and differential scanning calorimetry analyses showed that adding [N4444][SS] increases the CP film's glass transition temperature, indicating enhanced thermal stability. Overall, the study demonstrates that integrating an ionic liquid into CP films significantly improves their barrier capabilities against water and pressure, which has broad implications for various industrial applications.

Analysis of aerodynamic characteristics of drone wing based on CFD

In order to improve the aerodynamic characteristics of the drone wings, CFD method was used to simulate and calculate the lift coefficient, drag coefficient, and lift-drag ratio under different relative inflow velocities, as well as the velocity and pressure fields under different attack angles. Modal calculations were conducted on the wing to obtain the first four modal shapes, providing a basis for analyzing flutter characteristics. An iterative calculation method of incompressible potential flow-boundary layer based on surface element method was combined with the software XFOIL to optimize the airfoil at low wind speeds. The results indicate that the airfoil is susceptible to stall at high angles of attack, with the pressure of the separation flow being nearly equivalent to that at the separation point. Subsequent to separation, there is an increase in differential pressure resistance, resulting in a marked rise in the drag coefficient. At the optimized angle of attack, the lift-drag ratio of the optimized wing increases by 12.58 %, while there is a decrease of 0.084 % in lift coefficient and an increase of 11.21 % in drag coefficient.