Increase In Pressure Research Articles

Corticosteroids and glaucoma: How do treatments trigger ocular nerve damage? - A systematic literature review

Corticosteroids are steroid hormone derivatives produced by the adrenal glands. Corticosteroids in the health sector have been widely utilized as anti-inflammatory agents because of their strong and rapid effects. This study aimed to identify the impact of long-term corticosteroid use on eye damage. This study uses a systematic literature review, which is guided by the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) to the article screening process. The data of this study, in the form of demographic variables, route of administration, steroid type, comorbidities, and patient risk factors, were descriptively analyzed. As a result, 15 of the 22 articles were selected for analysis. Chronic corticosteroid administration may precipitate optic neuropathy, manifesting as glaucoma, which is characterized by progressive structural degeneration of retinal ganglion cells (RGCs) and concomitant visual function deterioration. The locus of primary pathological insult in glaucomatous conditions is the optic nerve head, specifically at the optic disc. This anatomical site is notable for the abrupt 90-degree angular deviation of RGC axons as they transition from the retinal nerve fiber layer to their trajectory within the optic nerve proper. The use of corticosteroids can damage ocular nerve tissue through an increase in intraocular pressure (IOP) beyond 21 mmHg. This increase in IOP is due to changes in the microstructure of the trabeculum webbing, resulting in increased obstruction to the outflow of aqueous humor.

Electroencephalographic depression after abruptly increasing partial pressure of end-tidal carbon dioxide: a case series

BackgroundProlonged electroencephalographic depression during surgery is associated with poor outcomes for patients. However, the published literature on electroencephalographic depression caused by a sudden increase in the partial pressure of end-tidal carbon dioxide (PETCO2) is lacking.Case presentationWe report four patients who were scheduled for laparoscopic liver surgery under general anesthesia. During the process of EEG monitoring with Sedline, four patients experienced electroencephalographic depression closely after a sudden increase in PETCO2. The four patients showed that electroencephalographic depression mainly manifested as a slow in EEG frequency, a reduction in the amplitude and power of EEG, and a decrease in spectral edge frequency. Patient state index was elevated in three cases.ConclusionsTo summarize, our patients showed EEG depression when PETCO2 suddenly increased, which suggests that clinical doctors should be alert to electroencephalographic depression when the PETCO2 abruptly increases. EEG monitoring devices should be applied in patients with possible hypercapnia. Anesthesiologists must comprehensively interpret the raw EEG, spectral edge frequency, and density spectral array data, in addition to patient sedation index values.

Molecular simulation study of adsorption-diffusion of CH4, CO2 and H2O in gas-fat coal

In order to clarify the microscopic dynamics mechanism of CH4, CO2 and H2O adsorption and diffusion in coal, and to reveal the mechanism of the influence of different temperatures and pressures on the adsorption and diffusion characteristics of coal adsorbed CH4, CO2 and H2O molecules. In this paper, the macromolecular structure model of Jixi gas-fat coal was constructed, based on the Giant Canonical Monte Carlo (GCMC) and Molecular Dynamics (MD) methods. The adsorption-diffusion characteristics of CH4,CO2 and H2O single-component gases in the gas-fat coal macromolecule model at temperatures ranging from 273.15 K to 313.15 K and pressures ranging from 0.01 MPa to 15 MPa were investigated by using Material Studio software. The research results indicated that: The adsorption of three gases, CH4, CO2 and H2O, increased with the increase of equilibrium pressure, and the adsorption isotherms conformed to Langmuir type I isotherms. The amount of saturated adsorption of CH4 ranged from 11.18 to 14.37 ml/g, the saturated adsorption of CO2 ranged from 20.40 to 24.70 ml/g, and the saturated adsorption of H2O ranged from 66.61 to 84.21 ml/g. With the increase of temperature, the saturated adsorption of CH4 and CO2 both decreased, and the saturated adsorption of H2O firstly increased and then decreased, and the adsorption of H2O by low temperature and high temperature had both an inhibitory effect on the adsorption of H2O. The potential energy distributions of CH4, CO2 and H2O molecules are poisson distributed. The absolute values of the most available interaction energies are, from highest to lowest: H2O > CO2 > CH4; the activation energies for diffusion of CH4, CO2 and H2O are 12.20 kJ/mol, 3.36 kJ/mol, and 8.47 kJ/mol, respectively, and the diffusion of CO2 is the more likely to occur. The adsorption of CH4 and CO2 in coal is physical adsorption, while the adsorption process of H2O molecules is beyond the scope of physical adsorption. The absolute value of the interaction energy is H2O > CO2 > CH4 in descending order.

Study on combustion and emission characteristics of hydrogen/air mixtures in a constant volume combustion bomb

Hydrogen is an environmentally-friendly fuel with the characteristics of low carbon, high calorific value, and extensive combustible range, making it an optimal alternative fuel for internal combustion engines. In this study, an experiment using a spherical constant volume combustion bomb (CVCB) was conducted to investigate the combustion and emission characteristics of hydrogen/air mixtures. The results shows that the flame propagation velocity of hydrogen laminar flow initially increases and then decreases with the excess air coefficient (λ), reaching peak at λ = 0.6, and the flame becomes unstable on the side of lean burning (λ > 1.0). Both the NOx emissions and the average temperature in the CVCB initially rise before eventually declining with the λ, the peak values for both NOx emission and mean temperature are reached at λ = 1.0. The dilution of N2 inhibits the laminar combustion and emission of hydrogen. As the dilution rate of N2 increases, little change occurs in the Markstein length, while flame propagation velocity, NOx emission, and average temperature all decrease. An increase in initial pressure hinders the development of the initial flame, while promoting the formation of cellular structure within the flame. Consequently, unstable combustion leads to a rapid increase in flame propagation speed during later stages. The average temperature inside the CVCB and the NOx emission increase by 6.6 % and 25.9 %, respectively, with the initial pressure increasing from 0.1 MPa to 0.5 MPa. On the other hand, an increase in initial temperature can facilitate flame development and results in an increased flame propagation speed. Especially, Markstein length is less sensitive to changes in initial temperature than to changes in initial pressure. The average temperature and NOx emission present a pattern of increasing first and decreasing then with the increase in initial temperature. These results have provided empirical evidence for optimizing the combustion and emission control of hydrogen engines.

Numerical investigation of the flow characteristics inside a supersonic vapor ejector

Integrating a vapor ejector with an air-cooled absorption cooling system (ACS) requires understanding how the ejector responds to varying condenser conditions and how the geometrical parameters affect the system's performance. This study provides a numerical investigation of the flow characteristics inside supersonic vapor ejectors. The primary objectives were identifying the best nozzle design for ACS and explaining how the secondary flow responds to different back pressures. The developed model was validated against experimental data and a one-dimensional model. Despite exhibiting increased flow fluctuations, the convex nozzle achieved an entrainment ratio of 0.4. This value was 4.9 % and 7 % higher than the values obtained by the straight and the concave nozzles, respectively. In contrast, the concave nozzle exhibits better flow stability and pressure recovery, which are considered appealing for the air-cooled ACS. The straight nozzle emerged as a balanced alternative, offering moderate entrainment alongside favorable flow stability. Moreover, secondary flow behavior at different operating modes was elaborated. Secondary flow choked at back pressures between 60–70 kPa, indicating optimal entrainment. However, at 75–80 kPa, while the secondary flow was entrained, it failed to reach sonic speed due to high-pressure waves, resulting in the sub-critical condition. Further increases in back pressure to 85–90 kPa induced back-flow due to elevated local static pressure. Mach number profiles at the mixing tube entrance remained consistent under critical operation but deviated post-critical back pressure, reflecting altered flow characteristics downstream of the mixing tube. Such elaboration of flow dynamics within ejectors paves the way for innovative designs of vapor ejectors, potentially developing ACS.

Efficacy of Molding Helmet Therapy following Suturectomy for Craniosynostosis: A Single-center, Retrospective Analysis in Japan

Craniosynostosis limits normal cranial growth, significantly affecting the growth and development of children. This increase in intracranial pressure results in significant cosmetic and functional losses. This study investigated the efficacy of combining molding helmets with suturectomy for craniosynostosis. Patients who underwent suturectomy and molding helmet therapy for craniosynostosis at a single institution between 2017 and 2024 were included. Changes in cephalic index (CI) and cranial vault asymmetry index (CVAI) were analyzed. A total of 14 patients (12 males, 2 females) were included, with a median age of 4.5 months (2–6 mo). The affected sutures were as follows: sagittal (n=8), bilateral coronal (n=4), unilateral coronal (n=1), and lambdoid (n=1) sutures. The median duration of postoperative molding helmet therapy was 44.5 weeks. For the sagittal suture group, the median preoperative CI, median postoperative CI, and rate of change were 72.0 (68.3–85.8), 77.0 (72.1–86.4), and 0.0646, respectively. For the bilateral coronal suture group, measurements for the same parameters were 104.0 (99.3–110.0), 92.5 (89.1–94.5), and 0.1114, respectively. For the unilateral coronal group, the measured parameters were 89.0 (87.7–91.2), 84.0 (81.2–87.1), and 0.059, respectively. Although all suture types showed improvement in cranial shape, with sagittal synostosis showing the most significant change, our findings did not support the added benefit of molding helmet therapy. Overall, the study suggests that suturectomy is a crucial first step in craniosynostosis treatment, leading to improvements in cranial morphology and growth.

Application of the K-Nearest Neighbor Method for Classification of Hypertension Diseases (Case Study: Stabat Health Center)

Globally, the WHO (World Health Organization) estimates that non-communicable diseases cause about 60% of deaths and 43% of diseases worldwide. Hypertension is a disease that occurs due to an increase in blood pressure in humans. It is difficult to know if a person has hypertension, without measuring the patient's blood pressure. According to the American Heart Association (AHA), the number of Americans over the age of 20 suffering from hypertension has reached 74.5 million, but nearly 90-95% of cases have no known cause. It is estimated that about 80% of the increase in hypertension cases will occur mainly in developing countries by 2025, from 639 million cases in 2000. This number is expected to increase to 1.15 billion cases in 2023. This study uses a quantitative approach with experimental methods to test the application of K-Nearest Neighbor (KNN) in the classification of hypertension diseases at the Stabat Health Center. The description of the results obtained is to make the right decision regarding when and how to treat the disease to prevent the worst possibility for patients by classifying the severity of hypertension both in normal circumstances, prehypertension, stage 1 hypertension, and stage 2 hypertension. The results of the trial show that the KNN model is able to provide accurate predictions based on patient history data available at Stabat Health Center.

GEOMECHANICAL MODELING OF RESERVOIR DYNAMICS ASSOCIATED WITH SHALLOW INJECTION AND PRODUCTION IN THE DELAWARE BASIN

The Permian Basin is an area of active hydrocarbon production and saltwater disposal, as well as associated induced seismicity and other geomechanical responses that threaten the surface environment. Among the important but not yet fully answered questions are: (i) what are the temporal and spatial changes in stress and pore pressure in response to fluid injection and production, and (ii) how do these changes relate to slip on pre-existing faults and surface deformation? We simulate stress and pore pressure responses to saltwater injection in the Delaware Mountain Group and production from the Wolfcamp and Bone Spring Formations with the aid of 2D geomechanical simulations that capture key mechanical stratigraphic units and representative faults. Primary loading consists of localized pore pressure changes that represent fluid injection into the Delaware Mountain Group and production from the lowermost portion of the Bone Spring Formation, the entire Wolfcamp A Formation, and the uppermost portion of the Wolfcamp B Formation. Injection leads to pore pressure increase, vertical extension, reduction in mean stress, and increase in differential stress in the Delaware Mountain Group. Production leads to decrease in pore pressure, vertical contraction, increase in mean stress, and increase in differential stress in the Bone Spring and Wolfcamp A and B Formations. The net effect of injection and production in our generalized simulations is normal faulting slip on faults that are relatively shallow in the subsurface, similar to faults that are known to have produced seismogenic rupture. The combination of injection and production reproduces a spatially-variant trend in uplift and subsidence, consistent with regional patterns measured in the study area via InSAR analysis. The modeled scenarios with shallow injection and/or production caused only small (lt;0.2 MPa) stress perturbations to propagate downward to basement, which would be unlikely to cause instability of deep-seated seismogenic faults.

Emergence of topological phase and non-trivial surface states in rare-earth semimetal GdSb with pressure

Abstract We study the evolution of band topology under external pressure in rare-earth gadolinium mono-antimonide (GdSb) using first-principles calculations. This material crystallizes in a rocksalt-type structure and shows a structural phase transition (SPT) to a CsCl-type structure at 26.1 GPa. The phonon dispersions are analyzed to ascertain the dynamical stability of this material. We use hybrid density functional theory with the inclusion of spin–orbit coupling to investigate the structural, electronic, and topological phase transitions (TPTs). At ambient pressure, GdSb shows a topologically trivial state which is in agreement with existing experimental reports. The first TPT is observed at 6 GPa of hydrostatic pressure (at the high symmetry X-point) which is verified with the help of single-band inversion and surface state analysis along the (001) plane. The non-zero value of the first Z2 topological invariant and the presence of the Dirac cone also confirm the topological phase of this material. A further increase in pressure to 12 GPa results in two band inversions at Γ- as well as X-points, which corresponds to the trivial nature of GdSb. The same is also verified with (0; 000) values of Z2 topological invariants and a pair of Dirac cones in surface states. It is noted that the crystal symmetries are preserved throughout the study and the TPT values are much lower than the SPT pressure, i.e. 26.1 GPa.

Analysis of causes of traffic accidents for taxi drivers based on MIMIC and machine learning

Through questionnaire survey, information on individual attributes, physical fatigue perception, work pressure, risky driving behavior and traffic accident experience of 2391 taxi drivers was collected. The multi-indicator multi-cause (MIMIC) model was used for path analysis to explore the inducing effect of physical fatigue perception and risky driving behavior on traffic accidents, and to verify the influence of gender, age and work pressure on physical fatigue perception and distracted driving behavior. Four machine learning algorithms, logistic regression, naive Bayes, support vector machine and random forest, were selected to predict taxi accidents. The results show that the increase of physical fatigue perception, negligent driving behavior, aggressive driving behavior and distracted driving behavior can lead to an increase in accident rate, and gender, age and work pressure will affect the frequency of physical fatigue perception and distracted driving behavior. The accident prediction model based on machine learning has excellent effect, among which the random forest has the best prediction effect. The prediction accuracy of using single feature variables "risky driving behavior", "distracted driving behavior" and "physical fatigue perception" is acceptable. When the personal attribute indicators of "work pressure", "age" and "gender" are introduced, the prediction accuracy is further improved.

Research on Temperature–Pressure Coupling Model of Gas Storage Well during Injection Production

Periodic changes in wellbore temperature and pressure caused by the cyclic injecting and producing of gas storage wells affect wellbore integrity. To explore the distribution and influencing factors of wellbore temperature and pressure during gas storage well injection-production processes, based on energy conservation, momentum theorem, and the transient heat transfer mechanism of the wellbore, a temperature and pressure coupling model for gas storage injection-production wellbores was established, and a piecewise iterative method was used to solve the model equations. Compared with the field data, the predicted relative errors of the wellhead temperature and pressure were 2.30% and 2.07%, respectively, indicating that the coupling model has a high predictive accuracy. The influences of the injection-production conditions, tubing diameter, and overall heat transfer coefficient on the wellbore temperature and pressure distributions were analyzed through an example. When the gas injection flow rate increased by 1.5 times, the bottomhole temperature decreased by 37%. Doubling the overall heat transfer coefficient resulted in a 10% rise in the bottomhole temperature. An increase of 0.3 times in the gas injection pressure led to a 31% increase in bottomhole pressure. With a 1.5-fold increase in the gas production flow rate, the wellhead temperature rose by 28%, and the wellhead pressure dropped by 20%. The research in this paper can serve as a guide for the optimization design and safe operation of gas storage wells.

MTOR in the Development of Hypoxic Pulmonary Hypertension Associated with Cardiometabolic Risk Factors.

The pathophysiology of pulmonary hypertension is complex and multifactorial. It is a disease characterized by increased pulmonary vascular resistance at the level due to sustained vasoconstriction and remodeling of the pulmonary arteries, which triggers an increase in the mean pulmonary artery pressure and subsequent right ventricular hypertrophy, which in some cases can cause right heart failure. Hypoxic pulmonary hypertension (HPH) is currently classified into Group 3 of the five different groups of pulmonary hypertensions, which are determined according to the cause of the disease. HPH mainly develops as a product of lung diseases, among the most prevalent causes of obstructive sleep apnea (OSA), chronic obstructive pulmonary disease (COPD), or hypobaric hypoxia due to exposure to high altitudes. Additionally, cardiometabolic risk factors converge on molecular mechanisms involving overactivation of the mammalian target of rapamycin (mTOR), which correspond to a central axis in the development of HPH. The aim of this review is to summarize the role of mTOR in the development of HPH associated with metabolic risk factors and its therapeutic alternatives, which will be discussed in this review.

Periodontitis accelerates the onset of hypertension in spontaneously hypertensive rats, while the electrical activation of the carotid sinus nerve delays the beginning of the increase in blood pressure.

We have previously demonstrated that electrical stimulation of the carotid sinus nerve (CSN) protects the development of periodontitis. In the current study, we evaluated whether periodontitis accelerates the onset of hypertension in spontaneously hypertensive rats (SHR); and whether electrical stimulation of the CSN would delay the onset of hypertension. Three-week old SHR were implanted with electrodes around the CSN for electrical stimulation for 13 days. Bilateral ligation of the first molar and oral administration of Porphyromonas gingivalis induced periodontitis. The femoral artery of the SHR was cannulated, and 24 h later, in a conscious state, the blood pressure was recorded. Five-week old sham SHR (subjects without electrical stimulation of the CSN) did not demonstrate hypertension. However, when the SHR were submitted to periodontitis they exhibited hypertension at 5 weeks of age. Nevertheless, the stimulation of the CSN prevented the onset of hypertension. Periodontitis promoted alveolar bone loss in SHR; but, electrical stimulation of the CSN prevented this undesirable outcome following the exposure to periodontitis. Periodontitis accelerated the onset of hypertension in SHR; while the electrical stimulation of the CSN delayed the onset of hypertension.

HYPERTENSIVE CRISES: HYPERTENSIVE EMERGENCY AND CRISIS MANAGEMENT DURING ANESTHESIA

Introduction: hypertensive crisis is characterized by an acute and massive increase in blood pressure. Hypertensive crises encompass several clinical situations with different severity and prognosis, including hypertensive urgency and hypertensive emergency. The difference between the latter depends on whether the situation is life-threatening for the affected individual. Objective: to detail current information related to hypertensive crises, especially hypertensive emergency, definition, differentiation, etiology, epidemiology, pathophysiology, histology, clinical history, physical examination, management, differential diagnosis, prognosis and complications. Methodology: a total of 28 articles were analyzed in this review, including review and original articles, as well as clinical cases, of which 15 bibliographies were used because the other articles were not relevant to this study. The sources of information were PubMed, Google Scholar and Cochrane; the terms used to search for information in Spanish, Portuguese and English were: hypertensive crises, hypertensive emergencies, hypertensive emergencies, arterial hypertension. Results: approximately 1-2% of adults with hypertension suffer hypertensive crises. Multiple case series show that short-term treatment of hypertensive emergencies has good results; however, long-term results are unknown. The main drawback is that follow-up of individuals is lost and the medication regimen is frequently modified. Untreated hypertensive emergencies have very high morbidity and mortality and if the patient does not receive adequate education about the severity of hypertension, this trend is likely to continue. Conclusions: given the high prevalence of hypertension, it is crucial that health care professionals are able to differentiate between hypertensive emergencies and hypertensive emergencies to provide appropriate and timely treatment. Rapid blood pressure reduction is critical in the treatment of hypertensive emergencies. The choice of medications should consider both efficacy and safety to avoid further complications. A detailed clinical evaluation can help identify the underlying cause and guide treatment, highlighting the importance of an individualized approach. Lack of timely treatment can lead to severe consequences, emphasizing the need for proper management in critical situations. Constant training in the management of hypertensive emergencies is essential to reduce the morbidity and mortality associated with this condition.The management of hypertension during anesthesia is critical, as its prompt detection and control are fundamental to prevent serious complications. Despite the lack of specific criteria to suspend surgery in hypertensive patients, it is essential to evaluate each case individually, prioritizing target organ damage over blood pressure levels. KEY WORDS: crisis, emergency, urgency, hypertension.

Turbulent flow and wall forces in staggered square cylinder porous media: An LES Analysis

Abstract The Wall-Modeled-Large Eddy Simulation (WMLES) technique was used to analyze turbulent flow in a porous medium composed of a staggered arrangement of square cylinders. The study focused on a porosity range of 0.3 to 0.8 at a pore Reynolds number of 10×103. The research provides novel information on pressure and shear force distributions around the cylinders and time-averaged values of particle drag and fluctuating lift coefficients. Results indicate that the flow physics are mainly driven by an expansion region in front of the central particle and another in the rear, where the flow is contracted and strongly accelerated. In the first region, velocities, turbulence kinetic energy (k), and its dissipation rate (e) are attenuated by a sudden pressure increase, while in the contraction region, the effect is the opposite. As porosity decreases, flow gradients and the overall levels of k, e, and Reynolds stresses become more significant. Turbulent anisotropy increases as porosity decreases below 0.6. Hydrodynamic stresses in the last interval present relatively uniform levels, which is a unique feature that may be considered in designing dedicated engineering devices with controlled stresses.

Pressure-induced anomaly of transport properties and structural transition in layered ferromagnetic metal TlCo2S2

In this work, the structural and transport properties of ferromagnetic metal TlCo2S2 with ThCr2Si2-type crystal structure are systematically studied using high-pressure synchrotron x-ray powder diffraction, electrical transport measurements and first-principles calculations. All the resistances of TlCo2S2 between 1.4 GPa and 5.2 GPa exhibit an upturn at TS and an obvious hysteresis is observed below TS when measured in the cooling and heating processes. As the pressure increases, TS gradually increases and the resistances display a metallic behavior without any anomaly in the whole temperature region above 5.2 GPa, indicating that a possible structural phase transition occurs at TS and is beyond the room temperature above 5.2 GPa. High-pressure x-ray diffraction measurements combined with crystal structure prediction indicate that at room temperature TlCo2S2 undergoes a structural phase transition from a tetragonal phase (I4/mmm) to an orthorhombic structure (Bmab) at Pc ≈6.8 GPa, which is consistent with the results of the resistances under high pressure. Our results indicate that a first-order structural phase transition of TlCo2S2 is induced by high pressure and then results in the anomaly of the electrical transport properties.

Simulation and experimental research on the propagation mechanisms of acoustic energy inside the pipeline to detect the leakage

Leakage from pipelines has negative impacts on property and environment. The diameters of internal acoustic detectors in pipelines are small and not easily blocked, making it suitable for pipelines under various working conditions. Studying the characteristics of pipeline leakage sound signal and the propagation mechanisms within pipelines is crucial for timely detection of small leaks. In this study, a 3D simulation model of pipeline leakage was established, and a CFD/CAA hybrid calculation method was used to obtain effective leakage flow field information via LES. The equivalent sound sources in the flow field were extracted based on the Lighthill acoustic analogy theory. Determine the characteristic frequency range of the leakage sound signal was 1–2 kHz. This study founded that an increase in the leakage pressure and aperture size both lead to an enhancement in the leakage sound signal, and the propagation of leakage sound signal in pipelines is affected by background flow. An experimental pipeline leakage system was designed, and the accuracy of the simulation results was verified experimentally.

Dural arteriovenous fistula may be occluded through recanalization of impaired venous sinuses.

To investigate the effect and safety of recanalization of stenosed or occluded venous sinuses for dural arteriovenous fistulas (DAVFs) and possible mechanism of DAVF formation, patients with DAVF accompanied by venous sinus stenosis or occlusion treated with balloon angioplasty and/or stenting were retrospectively enrolled. The clinical data, treatment outcomes and complications were analyzed. In 7 patients enrolled, the DAVF was Cognard IIa grade in 3 (42.9% or 3/7) and IIa + b in 4 (57.1% or 4/7) patients, including complex DAVFs in 2 (28.6% or 2/7). The angioplasty procedure was successful in all (100%) patients, including complete cure in 3 (42.9% or 3/7) patients with the initial Cognard grade IIa, transformation from Cognard grade IIa + b to I in 2 (28.6% or 2/7) patients, and unchanged Cognard grade IIa + b in 2 (28.6% or 2/7) patients. The symptoms were all improved. At 3-month angiographic follow-up, 5 (71.4% or 5/7) cases were cured, whereas 2 cases still had grade I fistulas but no clinical symptoms. Staged embolization in 2 patients resulted in significant symptom improvement. At the last follow-up of a median 4 years, no clinical symptoms were present in 5 (71.4% or 5/7) patients, intermittent headache in 1 (14.3% or 1/7), and death from trauma in 1 (14.3% or 1/7). In conclusion, endovascular recanalization of occluded or stenosed venous sinuses using balloon angioplasty and stenting is able to induce occlusion of DAVFs and is a safe and efficient treatment approach for DAVFs which are possibly caused by significant pressure increase.

Outcomes of the Modified Warden Procedure for Partial Anomalous Pulmonary Venous Connection Drainage to a High Location in the Superior Vena Cava

To report the safety and effectiveness of a modified Warden procedure. Twenty-six (26) patients underwent modified Warden surgery at our centre from September 2017 to September 2021. In all patients, the superior vena cava (SVC) was reconstructed by turning the atrial wall in the main body of the right atrium upwards and applying fresh autologous pericardial patches. There were 13 male patients and 13 female patients, and the median age of the patients was 7.0 (range, 0.3-47.0) years. The median follow-up time after surgery was 47.0 (range, 32.0-80.0) months. The aortic cross-clamp time was 108.50±34.72 minutes, the cardiopulmonary bypass time was 154.81±41.65 minutes, the median postoperative mechanical ventilation time was 8.5 (range, 0.0-91.0) hours, the median intensive care unit stay was 43.5 (range, 15.0-352.0) hours, and the median length of postoperative hospital stay was 7.0 (range, 6.0-19.0) days. All patients were safely and successfully discharged from the hospital. No deaths or sinus node dysfunction occurred during the follow-up period. The mean gradient of the reconstructed SVC and/or the right pulmonary vein (PV) increased in eight patients and decreased to less than 1 mmHg in six patients. One (1) adult patient had already undergone two vascular interventions, and one child had persistent stenosis but did not undergo reoperation at the time of the study. In addition, two patients were subjected to pericardial windowing. A modified Warden technique using a right atrial flap and autologous pericardium effectively corrected the high-plane connection between the PVs and SVC. This technique effectively avoids sinus node dysfunction; however, a short-term increase in the differential pressure of the re-established SVC or PV after the procedure is acceptable, and reintervention is required only in rare cases.

Generalisation of the yield stress measurement in three point bending collapse tests: application to 3D printed flax fibre reinforced hydrogels

This paper describes the extrusion pressure's effect on composite hydrogel inks' filaments subjected to three point bending collapse tests. The composite considered in this work consists of an alginate-poloxamer hydrogel reinforced with flax fibres. Increased extrusion pressure resulted in more asymmetrical filaments between the support pillars. Furthermore, the material and printing conditions used in the present study led to the production of curved specimens. These two characteristics implicitly limit the validity of the yield stress equations commonly used in open literature. Therefore, a new system of equations was derived for the case of asymmetrical and curved filaments. A post-processing method was also created to obtain the properties required to evaluate this yield stress. This new equation was then implemented to identify the strength of failed hydrogels without flax fibre reinforcement. A statistical analysis showed this new equation's significance, which yielded statistically higher (i.e. 1.15 times larger) strength values compared to the numbers obtained with the open literature equations. At larger extrusion pressures, longer periods were needed for the material to converge towards its final shape. Larger extrusion pressure values led to lower yield stresses within the composite hydrogel filament: a 5 kPa increase in extrusion pressure lowered the yield stress by 19%. In comparison, a 15 kPa increase led to a 29% decrease in the yield stress. Overall this study provides guidelines to standardize three point bending collapse tests and analysis comparison between different materials.