Flow Analysis Research Articles

The impact of a variable-camber inlet guide vane on the performance of a highly loaded counter-rotating fan under variable working conditions

In this research, a variable-camber inlet guide vane (VIGV) is applied to a highly loaded counter-rotating fan for the first time at variable working conditions. Additionally, internal flow analysis of the highly loaded counter-rotating fan is performed to reveal the essential flow mechanism and determine its impact on overall performance. It is found that the through-flow capacity is improved with a decrease in the camber angle. At −10°VIGV, the through-flow capacity increases by 3.1% at the design speed, while the through-flow capacity is only increased by 0.7% at the low corrected speed. The main reason for this is that the through-flow capacity along the blade span of the high-pressure rotor can be increased at the design speed, while only part of the blade span can be increased at the low corrected speed. At the low corrected speed, with the increase in the camber angle, the isentropic efficiency can be effectively improved by the counter-rotating fan, and the isentropic efficiency increases by 1.43% at +20°VIGV. This is mainly due to the decrease in the camber angle reducing the low-pressure rotor's incidence angle along the blade span, which suppresses the flow separation of the low-pressure rotor's suction surface.

Abstract 009: Prototyping a Novel Balloon‐Stent Device for Treating Brain Aneurysms

Introduction Although neurointerventional technologies have advanced for aneurysms, current adjunctive devices such as stents and temporary balloons still present significant limitations. Balloons can provide a uniform surface and neck protection for improved coiling and embolic placement, but also occlude parent artery blood flow and increase the risk of intraoperative ischemia and thrombus formation. Further, their inflation and deflation processes often result in diffuse vessel trauma. Stent technologies can support the parent vessel at the aneurysm, but coils placed behind the stent during aneurysm treatment can become entangled. Additionality, permanent stent placement necessitates long‐term dual antiplatelet therapy (DAPT), presenting substantial bleeding risks to the patient. This project aimed to develop, build, and validate the Balloon‐Mesh (BM), a unique endovascular device that enhances aneurysm neck protection during embolic device placement while maintaining blood flow in the parent artery distal to the aneurysm. Doing so minimizes the risk of ischemia while providing excellent aneurysm neck protection, setting it apart from existing solutions. Aim 1 was to design and build BM prototypes for endovascular aneurysm treatment. Aim 2 was to assess the BM prototype in an in vitro aneurysm blood flow model. The impact of this study illustrates how a high‐density mesh device could be superior to current adjunctive devices, improving post‐operative outcomes and signaling a paradigm shift in stent‐assisted embolization technology. Methods Aim 1 Pressure drop across neurovascular stenosis greater than 25% is an ischemic risk. Fluid simulations showed that a BM device with a pore size of 200 does not pose significant ischemic risk while providing superior aneurysm neck protection. From simulations, three initial BM devices were created. They were designed to be self‐expanding, retrievable, and balloon‐shaped. Each prototype evaluated a different profile to identify the optimal shape for neck protection. Aim 2 The BM prototypes were deployed in aneurysm models with real‐time pressure recording. Fluoroscopy was utilized to visualize flow and record any variations or complications that might arise during device deployment. The prototype performance was directly compared to a control device (Pipeline Medtronic). Aneurysm neck coverage was evaluated through contrast injections. Results All BM prototypes were successfully tracked and deployed at the neck of the aneurysm. Flow analysis shows the BM does not pose an ischemic risk. Fluoroscopy indicates the control device did not significantly reduce the flow inside the aneurysm. By comparison, the BM prototypes significantly reduced flow into and out of the aneurysm while maintaining parent artery flow. Conclusion This project delivered on Aims 1 and 2 by developing three BM prototypes that optimized aneurysm neck protection while maintaining parent artery blood flow. The device performance was validated using multiple in vitro vessel models. We found that the BM successfully protected the neck of an aneurysm while maintaining parent artery blood flow, eliminating ischemic risk. Additionally, the BM prototypes outperformed the control at minimizing flow into the aneurysm. Future work includes modifying the BM size for various vessels, investigate compatibility with embolic devices (coil/liquid), and in vivo testing in preparation for an FDA submission.

A Type System for Data Flow and Alias Analysis in ReScript

A Type System for Data Flow and Alias Analysis in ReScript

HT-PGFV: Security-Aware Hardware Trojan Security Property Generation and Formal Security Verification Scheme

Property-driven hardware verification provides a promising way to uncover design vulnerabilities. However, developing security properties that check for highly concealed security vulnerabilities remains a significant challenge. In this paper, we propose a scheme, called HT-PGFV, to implement hardware Trojan security property assertion automatic generation and formal security verification for Trojan-infected designs. In our scheme, we develop a hardware Trojan security property assertion generation method for automated hardware which can extract hardware Trojan security properties from Trojan-infected designs by performing the three main steps of Trojan-infected signal identification based on feature matching, influence-cone-analysis-based Trojan path identification, and information flow trace mining, and formulate them as SystemVerilog assertions. In addition, we develop a formal security verification method based on information flow analysis which can formally verify hardware Trojan security properties and detect hardware Trojans violating information flow security policies by checking the security of information flows via our developed RT-level hardware information flow security models. The proposed method is demonstrated on several Trojan benchmarks from Trust-Hub. Experimental results show that our scheme can generate hardware Trojan security property assertions for Trojan-infected designs and detect information leakage and functionality change hardware Trojans activated by external inputs or internal conditions.

Optimization of The Role of Protocol and Communication of The Leadership of The Regional Secretary Office Sikka Regency in Public Information Services

This study aims to examine the optimization of the role of the Protocol and Communication of the Leadership (Prokompim) of the Sikka Regency Secretariat in providing public information services through the Sikka Buletin Facebook account. The focus of the study is to evaluate the effectiveness of social media content management and communication strategies to increase public involvement. A qualitative approach is used to describe content management based on observations, interviews, and documentation studies. Data were collected through interviews with the admin of the Sikka Buletin Facebook account and followers as well as analysis of published content. The data analysis technique adopted the Flow Analysis Models of Miles and Huberman, which include data reduction, data presentation, and verification to produce in-depth understanding. The results of the study indicate that although Prokompim has attempted to manage content using the 5W1H elements with a formal but relaxed communication style, there are still challenges in increasing audience engagement. The main findings include low public interaction with posted content and less than optimal time and collaboration in content management. This study recommends a more planned time management strategy, collaboration with related agencies to enrich content, and a focus on audience engagement to strengthen the relationship between the government and the community through social media.

Dynamic Analysis and Hazard Assessment of Debris Flows in Donghaolitaogao

Utilizing the FLO-2D software, the motion processes of debris flows in Donghaolitaogao under 20-year, 50-year, and 100-year return periods of rainfall are analyzed, revealing that as the rainfall return period increases, the debris flow velocity, accumulation depth, and accumulation area all significantly expand. Specifically, under the 20-year, 50-year, and 100-year rainfall conditions, the maximum debris flow velocities are 1.85 m/s, 1.95 m/s, and 1.99 m/s, respectively, while the maximum accumulation depths are 1.31 m, 1.33 m, and 1.35 m, and the total accumulation areas are 27,267.8 m2, 31,500.6 m2, and 33,901.3 m2, respectively. Using the depth of debris flow and the product of debris flow depth and velocity as evaluation indicators, the debris flow hazard assessment indicates that the Donghaolitaogao debris flow is primarily characterized by low- and medium-risk areas, with high-risk areas scattered sporadically along the central part of the channel. Moreover, as the rainfall return period increases, the area of high-risk zones continues to expand, gradually accounting for a larger proportion of the total hazard zone.

The comprehensive analysis of magnetohydrodynamic Casson fluid flow with rectangular porous medium through expanding/contracting channel

PurposeThis study examines fluid flow within a rectangular porous medium bounded by walls capable of expansion or contraction. It focuses on a non-Newtonian fluid with Casson characteristics, incompressibility, and electrical conductivity, demonstrating temperature-dependent impacts on viscosity.Design/methodology/approachThe flow is two-dimensional, unsteady, and laminar, influenced by a small electromagnetic force and electrical conductivity. The Hybrid Analytical and Numerical Method (HAN method) resolves the constitutive differential equations.FindingsThe fluid’s velocity is influenced by the Casson parameter, viscosity variation parameter, and resistive force, while the fluid’s temperature is affected by the radiation parameter, Prandtl number, and power-law index. Increasing the Casson parameter from 0.1 to 50 results in a 4.699% increase in maximum fluid velocity and a 0.123% increase in average velocity. Viscosity variation from 0 to 15 decreases average velocity by 1.42%. Wall expansion (a from −4 to 4) increases maximum velocity by 19.07% and average velocity by 1.09%. The average fluid temperature increases by 100.92% with wall expansion and decreases by 51.47% with a Prandtl number change from 0 to 7.Originality/valueUnderstanding fluid dynamics in various environments is crucial for engineering and natural systems. This research emphasizes the critical role of wall movements in fluid dynamics and offers valuable insights for designing systems requiring fluid flow and heat transfer. The study presents new findings on heat transfer and fluid flow in a rectangular channel with two parallel, porous walls capable of expansion and contraction, which have not been previously reported.

Holistic analysis of the dynamic stability of the Southern Cameroon Interconnected grid in contingency situations

The Southern Cameroon Interconnected Network (SIG) is depicted as a large-scale power system that has shown significant instability due to a series of blackouts in recent years. These blackouts are primarily attributed to major disruptions in transmission lines and energy deficits between supply and demand. The imbalance between power supply and demand necessitates the grid to operate near its stability limits, increasing the risk of blackouts. The necessity of investigating the dynamics of SIG behavior in response to observed contingency situations serves as the primary motivation for this study. To achieve this objective, the SIG was modeled using saturated generators with ZIP static loads. Through Newton-Raphson based power flow calculations, voltage magnitude profiles of the grid were obtained for each generation scenario. An N-1 contingency consisting of a standard Newton-based continuation power flow (CPF) analysis has identified line 5–6 as the most frequent worst case of line outage. Additionally, a short-term transient analysis was conducted under three-phase short-circuit, line outage and generator outage scenarios. In the event of a short-circuit, the Mangombe-225 bus experienced the most significant impact. Concerning line outages, line 1–5 had the most adverse effect on the grid's frequency stability. However, generation outages had a lesser impact on frequency stability compared to other disturbances. Lastly, modal analysis revealed that the grid exhibited weak stability with a critical mode identified at a frequency of 4.0267 Hz, exceeding typical values. This underscores the necessity of damping the grid oscillations for enhanced stability.

Modeling Population Mobility Flows: A Hybrid Approach Integrating a Gravity Model and Machine Learning

Population mobility between cities significantly affects traffic congestion, disease spread, and societal well-being. As globalization and urbanization accelerate, understanding the dynamics of population mobility becomes increasingly important. Traditional population migration models reveal the factors influencing migration, while machine learning methods provide effective tools for creating data-driven models to handle the nonlinear relationships between origin and destination characteristics and migration. To deepen the understanding of population mobility issues, this study presents GraviGBM, an expandable population mobility simulation model that combines the gravity model with machine learning, significantly enhancing simulation accuracy. By employing SHAPs (SHapley Additive exPlanations), we interpret the modeling results and explore the relationship between urban characteristics and population migration. Additionally, this study includes a case analysis of COVID-19, extending the model’s application during public health emergencies and evaluating the contribution of model variables in this context. The results show that GraviGBM performs exceptionally well in simulating inter-city population migration, with an RMSE of 4.28, far lower than the RMSE of the gravity model (45.32). This research indicates that distance emerged as the primary factor affecting mobility before the pandemic, with economic factors and population also playing significant roles. During the pandemic, distance remained dominant, but the significance of short distances gained importance. Pandemic-related indicators became prominent, while economics, population density, and transportation substantially lost their influence. A city-to-city flow analysis shows that when population sizes are comparable, economic factors prevail, but when economic profiles match, living conditions dictate migration. During the pandemic, residents from hard-hit areas moved to more distant cities, seeking normalcy. This research offers a comprehensive perspective on population mobility, yielding valuable insights for future urban planning, pandemic response, and decision-making processes.

Comprehensive literature review of material flow analysis (MFA) of plastics waste: recent trends, policy, management, and methodology

Comprehensive literature review of material flow analysis (MFA) of plastics waste: recent trends, policy, management, and methodology

Analysis of Unsteady Flow and Interstage Interference of Pressure Pulsation of Two-Stage Pump as Turbine Under Turbine Model

The process pump as turbine (PPAT) serves as a crucial component for recovering high-pressure energy from mediums used in chemical and refining processes. Ensuring the long-term safe and stable operation of PPAT in high-temperature and high-pressure environments is essential, with pressure pulsation being one of its most significant external characteristic indicators. This study investigates the evolution of vortex structure distribution and the generation and propagation mechanisms of pressure pulsation in a two-stage PPAT operating in turbine mode. Results indicate that the uniformity of the pressure coefficient (Cp) gradient distribution is poorer in the first stage runner compared to the second stage, with a larger distribution area of high-strength vortices. In the draft tube, vortex strength increases with rising flow rates, and the flow around the circular cylinder on one side gradually develops to both sides. In the two-stage diffusers, the primary source of pressure pulsation is the dynamic and static interference effect between the two impellers and the corresponding diffuser tongue. The interstage interference with a frequency of n*15fn is most pronounced in the inflow runner, gradually weakening along the flow direction, and ultimately disappearing in the draft tube. In addition, more low-frequency signals with a frequency of 0.5fn are captured in the draft tube under large flow conditions, which is mainly generated by the vortex band in the draft tube. The low-frequency pulsation energy is high and the attenuation is slow, which has a great destructive effect on the energy recovery system of the PPAT.

Optimal homotopy analysis of unsteady second-grade tri-hybrid nanofluid flow with radiative impact between parallel disks

The research explored the critical examination of unsteady second-grade Tri-hybrid nanofluid flow between parallel disks within a Darcy-Forchheimer medium with porosity. The study focusses on a fluid comprised of Au, TiO2, and Ag solid nanoparticles within blood, encompassing various shapes such as brick, blade, and platelet. It thoroughly investigated the impacts of Soret and Dufour effects in conjunction with MHD, joule heating, and the presence of a heat source. Furthermore, it elucidated thermally radiative effects and considers slip and convective boundary conditions, as well as mass transfer with a chemical reaction. The research also encompassed the influence of suction/injection on the squeezing flow. As the second-grade fluid parameter increases, the velocity of the fluid rises, especially when the η < 0.4. However, when η > 0.4, the velocity decreases. Additionally, the Biot numbers exhibit different effects depending on their application to the lower and upper disks. Specifically, Bi1 enhances the system's temperature, while Bi2 reduces it. The comprehensive mathematical formulation incorporates all these effects, later transformed into ODEs using similarity transformation conditions. Employing the optimal homotopy analysis technique in Mathematica software, the study graphically characterized velocity, temperature, and concentration profiles. The research's credibility is ascertained through validation against previous work by other researchers.

ANALISIS KETERSEDIAAN DAN KEBUTUHAN AIR BAKU DISTRIK BONGGO KABUPATEN SARMI

The development of an area will cause the demand for water to continue to increase along with thepopulation growth rate. The fulfillment of food needs and the activities of the population are always closely relatedto the need for water. The demands are unavoidable but must be predicted and planned for optimal utilization.The tendency that often occurs is the imbalance between water availability and water demand. To achieve abalance between water demand and availability in the future, efforts are needed to assess the components of rawwater availability and demand as clean water sources. The source of clean water for the people of Bonggo District, Sarmi Regency, comes from borehole pumps,shallow wells (pumps), and rainwater. The analysis results on the need for domestic and non-domestic clean waterin the Bonggo District in 2023 show a total requirement of 210.38 liters/day or 0.0024 m3/second. The need forclean water is expected to increase by 2043, with the total requirement for domestic and non-domestic clean waterreaching 285,820 liters/day or 0.0033 m3/second. The availability and need for clean water sourced from rawwater that can be utilized as clean water comes from pump bore wells as a suitable raw water source. In terms ofquantity, it is available 24 hours a day and throughout the year. The investigation results of the pump bore wellraw water source meet the clean water quality requirements according to Government Regulation No. 82 of 2001,Level II. This is supported by groundwater, obtained through the analysis of geological conditions, land cover,morphology, and river flow, which have a high to very high groundwater potential score, located in the northernpart of Bonggo District. Economically, in terms of quantity, rainwater can be used as clean water due to its sufficientavailability, with high rainfall (104,775 mm/year) and year-round service (continuity), and in terms of quality, theresults of rainwater quality tests meet the clean water standards according to quality standards.

LitChemPlast: An Open Database of Chemicals Measured in Plastics.

Plastics contain various chemical substances, which can impact human and ecosystem health and the transition to a circular economy. Meanwhile, information on the presence of individual substances in plastics is generally not made publicly available, but relies on extensive analytical efforts. Here, we review measurement studies of chemicals in plastics and compile them into a new LitChemPlast database. Over 3500 substances, stemming from all plastic life-cycle stages, have been detected in different plastics in 372 studies. Approximately 75% of them have only been detected in nontargeted workflows, while targeted analyses have focused on limited well-known substances, particularly metal(loid)s, brominated flame retardants, and ortho-phthalates. Some product categories have rarely been studied despite economic importance, e.g., consumer and industrial packaging (other than food packaging), building and construction, and automotive plastics. Likewise, limited studies have investigated recycled plastics, while existing measurements of recycled plastics show higher detection frequencies and median concentrations of regulated brominated flame retardants across many product categories. The LitChemPlast database may be further developed or utilized, e.g., for exposure assessment or substance flow analysis. Nonetheless, the plethora of relevant substances and products underscores the necessity for additional measures to enable the transition to a safe circular plastics economy.

Hypermobility of a Catastrophic Earthquake-Induced Loess Landslide

Landslide mobility refers to how far and fast a landslide can move downslope. It controls landslide impact areas and damage power. Highly mobile landslides are often initiated on slopes steeper than 30°. However, on 18 December 2023, an earthquake-induced landslide (35°52′54″N, 102°51′10″E) exhibited extraordinary mobility, with an overall travel angle of 1.5°, breaking an on-land landslide record. The landslide originated on a gentle slope (3.6°), eroded an earth dam along its travel path, and finally destroyed 51 houses and claimed 20 lives. Remote sensing and field surveys were conducted to provide morphological characteristics of the hazard chain. A numerical program, EDDA (Erosion–Deposition Debris Flow Analysis), was employed to reproduce the flow dynamics and investigate the causes of hypermobility. The findings reveal three primary causes of hypermobility: (1) liquefaction of the saturated silty loess stratum due to the combined effects of irrigation activity and seismic loading, (2) the loose and macro-pore structure of loess, and (3) confined topography and icy channel bed. The mechanisms revealed have broad implications for understanding fluidized mass movements on gentle slopes in seismically active regions.

Comparative Study on the Application Efficacy of Small Disturbance Equation versus One-Dimensional Euler Equation in Nozzle Flow Analysis

This paper presents a numerical simulation study of subsonic and supersonic nozzle flow regimes utilizing the Small Disturbance Equation (SDE), implemented through Python to analyze flow stability under various boundary conditions. The SDE, extensively applied in aerospace, meteorology, and fluid mechanics, offers a critical framework for examining aircraft stability and maneuverability, essential for ensuring flight safety. Additionally, its application extends to spacecraft stability and control in aerospace science. The findings from this study reveal that subsonic flows, characterized by their stability and smoothness, respond more predictably under varying boundary conditions compared to their supersonic counterparts. Conversely, supersonic flows demonstrate increased sensitivity to changes in boundary conditions, resulting in more complex flow patterns. This sensitivity underscores the need for precise control mechanisms in supersonic applications to maintain flow stability and ensure the safety and efficiency of aerospace operations. The simulations underscore the practical importance of the SDE in advancing the understanding of dynamic flow problems across different scientific and engineering disciplines.

Advanced Numerical Techniques for Supersonic Flow Analysis: From Euler Equations to Practical Applications in Aerospace and Turbomachinery Engineering

This paper explores advanced numerical techniques for analyzing supersonic flow, with a particular focus on the application of Euler equations in aerospace and turbomachinery engineering. Theoretical foundations such as boundary conditions, error evaluation, grid partitioning, and the Successive Over-Relaxation (SOR) method are thoroughly examined. Rigorous numerical simulations are conducted to investigate the final velocity field distribution and convergence characteristics under various conditions. The research underscores the precision and efficiency of these numerical methods, highlighting their practical applications in the aerodynamic design of aircraft and potential use in turbomachinery design. The findings contribute significantly to the advancement of computational fluid dynamics in supersonic flow regimes, providing valuable insights for engineers and researchers engaged in this specialized area. The study not only enhances understanding of complex flow dynamics but also supports the development of more effective engineering solutions in high-speed applications.

The Impact of a Non-Uniform and Transient Magnetic Field on Natural Convective Jeffrey Fluid Flowing over a Heated Porous Plate: A Comparitive Study

Examining the effects of varying transient magnetic fields and their orientations on boundary layers aids in understanding the flow in complex surface geometries, turbulence control, drag reduction, aircraft and ship design, groundwater management, and the study of construction and coastal engineering. The study introduces a novel dynamics of the boundary layer of a natural convective Jeffrey fluid flowing over an erect porous moving plate under the influence a non-uniform and transient magnetic field M ˜ that grows exponentially over time with α as an accelerating parameter. The governing partial differential equations (PDEs) were non-dimensionalized using similarity variables and then solved analytically using the perturbation technique. The impact of various thermosphysical properties including chemical reactions, thermal source, Jeffrey fluid parameter and plate permeability on the fluid flow were presented graphically utilizing finite difference approximation(FDA) technique in MATLAB ODE15s solver. The study highlighted a notable decrease in shear stress (skin friction) by introducing M ˜ to the vertical plate results in the reduction of momentum boundary layer, accompanied by an increment in thermal boundary layer. Also, the results shows that increasing the magnitude of α leads to decrease the velocity and increase the temperature distribution curve. Additionally, the concentration profile was also found to decrease with stronger chemical reactions. Furthermore, key parameters like heat and mass flux were estimated and discussed through comparison tables. Understanding the effects of unsteady and externally applied increasing magnetic field M ˜ on viscous fluid flow have potential applications in biomedical engineering, such as the design of magnetic drug delivery systems and the analysis of blood flow in human body.

Computational analysis of pulsatile blood flow and heat transport dynamics in middle cerebral artery aneurysms in different body physiologies

This paper presents a comprehensive hemodynamic evaluation of two endovascular techniques for treating cerebral aneurysms. Using the finite volume method, we simulated pulsatile blood flow and heat transport dynamics in two saccular aneurysms of varying sizes and shapes. We assessed hemodynamic factors under two coiling conditions with different porosities and deformation stages to identify the most effective treatment for each case. Our computational analysis reveals that stent and coiling applications are more efficient for aneurysms with low-sac volume. Notably, stent placement proves to be more effective than coiling in treating saccular aneurysms. Our findings indicate that stent-induced deformation sufficiently diverts the main blood flow, thereby reducing the risk of aneurysm rupture near the ostium region.

Impaired systemic microvascular function in patients with resistant arterial hypertension and microalbuminuria: an observational study

Abstract Background Systemic arterial hypertension (SAH) is one of the most prevalent diseases worldwide and is known to be associated with alterations of microvascular function. It is well known that microalbuminuria (MAU) is considered an early marker of renal and cardiac injury in SAH and is an independent risk factor for cardiovascular events in this population. Additionally, it is associated with altered endothelial function, which occurs from the early stages and can be considered an early marker. In some cases, SAH presents as resistant arterial hypertension (RAH), resulting in a worse prognosis compared to individuals with non-resistant hypertension. Moreover, MAU is associated with higher mortality, independent of glomerular filtration rate. Endothelial dysfunction is also a risk marker found in different conditions and can add to MAU in patients with RAH. Purpose To investigate systemic microvascular function in patients with RAH, with or without MAU. Methods 64 patients with RAH, of both genders (50% men), were evaluated, with 32 having MAU and 32 without MAU (defined as a urinary albumin/creatinine ratio between 30 and 300 mg/g in a routine urine sample). Microvascular function assessment was performed using a laser speckle system, allowing analysis of cutaneous microvascular flow. Flow measurements were expressed in arbitrary perfusion units (APU) divided by the mean arterial pressure to obtain cutaneous vascular conductance (CVC). A post-occlusive reactive hyperemia (PORH) test was performed, with brachial artery occlusion using a sphygmomanometer 50 mmHg above systolic pressure for 3 minutes; cutaneous flow was measured after release of the occlusion. Results Patients with or without MAU did not differ in terms of age, frequency of diabetes, and chronic kidney disease. The peak CVC values during PORH were 0.64 ± 0.15 and 0.55 ± 0.15 APU/mmHg in RH and RH + MAU patients, respectively (P=0.03). The delta values (peak – baseline) during PORH were 0.31 ± 0.11 and 0.25 ± 0.09 APU/mmHg in RH and RH + MAU patients, respectively (P=0.04)(Figure 1). Conclusions PORH-induced vasodilation was found to be reduced in patients with RAH and MAU compared to patients without MAU. This finding shows alteration of endothelium-dependent vasodilation mechanisms in these patients, indicating reduced systemic microvascular endothelial function. Endothelial dysfunction may be associated with glomerular permeability changes, contributing to MAU and further increasing the risk for these patients. This suggests the need for more intensive therapeutic interventions and better risk stratification for these patients, as endothelial dysfunction can be found in the early stages of the disease.Figure 1