Changes In Velocity Research Articles

Comparison of the imaging performance of time-of-flight MRA and ultrashort echo time MRA in flow diverters: A phantom study.

Flow diverters (FD) are innovative treatments for wide-neck intracranial aneurysms. After-treatment verification of embolization and parent vessel patency is crucial. While evaluation using time-of-flight magnetic resonance angiography (TOF-MRA) is useful, it suffers from signal loss within the FD due to susceptibility effects. This study evaluates the usefulness of ultrashort echo time MRA (UTE-MRA) for after-FD assessment compared to TOF-MRA. Vascular phantom experiments were conducted using FDs (FRED®, Pipeline®, Surpass Streamline®). TOF-MRA and UTE-MRA were performed under steady (10, 30, 50 cm/s) and pulsatile (17-61 cm/s, mean 34 cm/s) flow conditions using a 3 T MRI system. As evaluation metrics, relative in-FD signal (RIS) was calculated by comparing the signal intensity inside the FD to that without the FD to assess signal retention, and FD luminal to background signal ratio (FD-LBR) was calculated by comparing the signal intensity inside the FD to that of the surrounding background to evaluate vessel visibility. UTE-MRA showed higher FD-LBR values than TOF-MRA for all FDs (p < 0.01). For RIS, UTE-MRA was significantly higher for FRED® (p < 0.01), but different for other FDs except at 50 cm/s. FRED® exhibited the highest RIS and FD-LBR values under all conditions, followed by Pipeline® and Surpass Streamline®. Flow velocity changes resulted in minimal variations in RIS and FD-LBR values. UTE-MRA provides superior image quality for after-FD assessment, particularly in terms of FD-LBR, compared to TOF-MRA. Differences in FD materials and structures affect image quality. These findings suggest UTE-MRA's clinical utility in follow-up after-FD assessment.

Thermodynamic and Kinetic Behavior Study of Gas Bubbles in High‐Temperature Steel Melts

This study provides an exhaustive exploration of the thermal expansion of low‐temperature argon bubbles in high‐temperature molten steel and the resulting dynamic effects. The energy equation of compressible fluid simultaneously with the volume of fluid model under the Euler framework is solved. The generation and rising behavior of bubbles are validated through rigorous physical water model experiments. Findings reveal that, within a heating time of 0.2–0.45 ms, gas bubbles already complete 65–90% of their internal energy increase. The total heat transfer time and heat transfer coefficient of bubbles exhibit distinctive patterns influenced by the initial diameter and temperature of the bubbles. Specifically, under the conditions studied, bubbles exhibit a total heat transfer time of ≈20–60 ms, accompanied by a heat transfer coefficient ranging from 500 to 2600 W (m2 * K)−1. During the thermal expansion process, gas bubbles experience energy transfer and conversion within the two‐phase flow. This article establishes a dynamic model describing bubble thermal expansion in steel melts based on underwater bubble dynamics’ first principles. The model provides a quantitative depiction of instantaneous changes in bubble size, velocity, and kinetic energy under specific conditions.

Investigation of heat and mass transfer properties of the wave staggered round table cooling flow field with a three-stage forked distribution zone

Research on proton exchange membrane fuel cells (PEMFC) has mainly focused on the design of gas channels, often neglecting the effects of distribution zones and cooling flow fields (CFF) on the cell. Therefore, a novel bipolar plate (BP) structure of metallic material is proposed in this paper, which adopts a three-stage forked distribution zone and a wave staggered round table cooling flow field (WSRTCFF). This study systematically investigates the effects of WSRTCFF presence or absence, flow direction, velocity, and inlet temperature on heat and mass transfer as well as PEMFC performance. The results show that introducing WSRTCFF significantly improves temperature distribution in the flow field. Compared to hydrogen flow direction, oxygen flow direction not only effectively mitigates local hot spot effects but enhances current density by 12.55 % compared to no cooling. When coolant flow velocity is below 0.1 m/s, increasing velocity promotes system heat dissipation, enhancing working efficiency and cell stability. However, when velocity exceeds 0.1 m/s, the change in the flow velocity has minimal effect on PEMFC performance. Furthermore, comparative analysis of different coolant temperatures indicates that at 333.15 K, maximum temperature remains below 348.2 K, maintaining membrane hydration and achieving a good balance of substances, temperatures, and performance.

A simple model incorporating foam rheology to quantify foam penetration behaviour in EPB shield tunnelling

Fulfilling the role of a soil conditioner, foam plays a pivotal role in Earth Pressure Balance (EPB) shield tunnelling by enhancing soil properties such as lowering permeability and increasing flowability. This study introduces a macro-model designed to quantify foam penetration behaviour in saturated sand, utilising rheological properties. To validate this model, experiments were conducted to replicate the foam penetration behaviour. Six sand beds characterised by varying particle sizes, along with foam having an expansion ratio of fifteen, were employed for penetration tests under different hydraulic conditions utilising a sand column device. The rheological profile of the foam is described by the power-law model, as also found by rheometer tests, although with different parameters. The flow behaviour of foam within the sand column conforms to the flow equation that governs power-law fluids in porous media. The developed model effectively predicts the foam penetration process under varying hydraulic conditions compared with the experimental results. Furthermore, the fitting results of the experimental data indicate that the flow behaviour index of the foam remains approximately 0.09 across all tests, regardless of the type of sand used. In contrast, the model-derived generalised permeability coefficient strongly correlates with the effective particle size (d10) of the sand bed. Overall, the model effectively quantifies the foam penetration behaviour, accounting for changes in infiltration velocity and pore water pressure, which is essential for understanding the transfer of support pressure in EPB shield tunnelling.

Kinetic description and macroscopic limit of swarming dynamics with continuous leader–follower transitions

In this paper, we derive a kinetic description of swarming particle dynamics in an interacting multi-agent system featuring emerging leaders and followers. Agents are classically characterized by their position and velocity plus a continuous parameter quantifying their degree of leadership. The microscopic processes ruling the change of velocity and degree of leadership are independent, non-conservative and non-local in the physical space, so as to account for long-range interactions. Out of the kinetic description, we obtain then a macroscopic model under a hydrodynamic limit reminiscent of that used to tackle the hydrodynamics of weakly dissipative granular gases, thus relying in particular on a regime of small non-conservative and short-range interactions. Numerical simulations in one- and two-dimensional domains show that the limiting macroscopic model is consistent with the original particle dynamics and furthermore can reproduce classical emerging patterns typically observed in swarms.

Association of mid-regional pro-adrenomedullin with office and 24-h ambulatory blood pressure in a Swiss general population sample.

Adrenomedullin (ADM) is a potent vasodilator. The association between plasma ADM levels and blood pressure (BP) remains unclear. We assessed the association between mid-regional-pro-ADM (MR-proADM) and BP in a multicenter population- and family-based cohort. We used data from the Swiss Kidney Project on Genes in Hypertension (SKIPOGH). We included participants present at both baseline and 3-year follow-up (N = 843). We examined the association of baseline MR-proADM with baseline office and 24 h ambulatory BP as well as the 3-year change in office BP. In secondary analyses, we studied the association between baseline MR-proADM and 3-year changes in pulse wave velocity (PWV), renal resistive index (RRI) and augmentation index (AI). Mixed-effects linear regression models were used. In cross-sectional analyses, MR-proADM was negatively associated with office, 24-h and daytime diastolic BP (DBP). MR-proADM was positively associated with nighttime systolic BP (SBP). In longitudinal analyses, baseline MR-proADM was associated with an increase in office SBP and pulse pressure (PP) over 3 years [β (95% CI): 8.2 (0.4, 15.9) and β (95% CI): 6.4 (0.3, 12.4), respectively] but not with changes in PWV, RRI and AI. The cross-sectional negative association of MR-proADM with DBP is in line with known vasodilatory properties of ADM. The positive association between MR-proADM and nighttime SBP at baseline may reflect endothelial dysfunction believed to be part of the pathogenesis of nocturnal hypertension. The association of higher baseline MR-proADM levels with increased SBP and PP at 3-year follow-up suggests that ADM levels could be a marker of cardiovascular risk.

Design of bypass structure and dynamic motion simulation for ultra-large diameter pipeline inspection gauge

Aiming at the problem of controlling the operating velocity of a large-diameter heavy-duty pipeline inspection gauge (PIG), this paper designs the bypass structure to study the velocity change and flow field state when the Ø1219 mm PIG is operating in pipeline with different bypass rates. Fluent is applied to numerical simulation of the fluid-structure interaction flow field based on the dynamic mesh method. The results show that: the bypass rate of 2%–3% can satisfy the velocity of PIG in 3–5 m/s reasonable interval. The larger the bypass rate is, the larger the turbulence intensity is, and the gradual increase of the pressure difference suffered by the PIG. The operating velocity of the PIG can be regulated more accurately by corresponding to the bypass rate and the pressure difference front and rear. Comparing the experimental and simulation results, the error rate of the velocity decrease with bypass rate of 1%–3% is 12.8 %.

Efficient navigation of cargo-towing microswimmer in non-uniform flow fields

The vision of deploying miniature vehicles within the human body for intricate tasks holds tremendous promise across engineering and medical domains. Herein, optimal navigation of a cargo-towing swimmer under an applied zig-zag flow is studied by employing direct numerical simulations coupled with a deep reinforcement learning algorithm. Tasks include navigation in flow and shear-gradient directions. We initially explore combinations of state inputs, finding that optimal navigation necessitates swimmers to perceive hydrodynamics and alignment, surpassing reliance solely on hydrodynamic signals while considering their memories. Next, we study combinations of action spaces, allowing dynamic changes in swimming and/or rotational velocities by tuning B1 and C1 parameters of the squirmer model, respectively. By keeping both parameters fixed, cargo-towing swimmers demonstrate superior performance in the flow direction compared to swimmers without load due to tumbling movements influenced by shear flow. In the shear-gradient direction, swimmers without load outperform cargo-towing swimmers, with performance decreasing as load length increases. Across the combination of allowing B1 and C1 to change, the policies from solely dynamic B1 actions demonstrate superior navigation. The policies are then used as a showcase against naive cargo-towing and inert colloidal chains. A t-distributed stochastic neighbor embedding analysis reveals the complex interplay between perceived hydrodynamic signals and swimmer position. In the flow direction, swimmers align effectively with regions of maximum velocity, while in the shear-gradient direction, periodic transitions from minimum to maximum state values occur. Comparing pullers, pushers, and neutral swimmers, cargo-towing swimmers show a reversal in swimming velocity trends, with pullers outpacing neutral and pusher swimmers, irrespective of load lengths. Published by the American Physical Society 2024

Numerical Simulation Study on Rotary Air Preheater Considering the Influences of Steam Soot Blowing

The ash deposition is a general problem that needs to be solved effectively for the rotary air preheater of the coal-fired boiler. Taking the rotary air preheater of a 600 MW power station as the object, the mesh model of the flue gas side of the air preheater, considering the influences of steam soot blowing, is established using the Gambit 2.4.6 software. Based on the SIMPLE algorithm, the velocity field and the temperature field in the air preheater under varied working conditions are simulated using the software of Ansys Fluent 2021R1, and the influences of the boiler load, the operation parameters of the steam soot blower, and the running and outage of the soot blower on the flue gas velocity distribution in the depth direction of the corrugated plates, the soot-blowing coverage area, the inlet flue gas velocity, and the inlet flue gas temperature of the corrugated plates are analyzed. Under the base working condition, the flue gas velocity on the axis of the steam nozzle first decreases rapidly with increasing the corrugated plate depth (Z &lt; 1.0 m), and then it decreases slowly with an almost equal slope. The longitudinal flue gas velocity has a positive correlation with the boiler load. The longitudinal flue gas velocity obviously decreases when the boiler load is decreased, and its reduction increases as the corrugated plate depth increases. It is one reason that the ash deposition is prone to occur on the cold end surface of corrugated plates under the condition of low boiler load. The longitudinal flue gas velocity increases with the soot-blowing steam velocity increasing when the corrugated plate depth is less than 1.5 m, but after that, it is almost not affected by the change in soot-blowing steam velocity. The soot-blowing coverage area has a negative correlation with the boiler load but a slight positive correlation with the steam velocity of the soot blower on the whole. The inlet flue gas velocity of the corrugated plates has a positive correlation with the boiler load and the inlet steam velocity of the soot blower. The average inlet flue gas velocity decreases by 21.7% when the boiler load is reduced by 50%. For every 5 m/s variation in the inlet steam velocity, the inlet flue gas velocity changes by about 10–14% whether the steam soot blower is put into operation or not, which has an obvious effect on the inlet gas velocity of the corrugated plates. The inlet flue gas temperature of the corrugated plates is, respectively, positively correlated with the boiler load and the inlet steam temperature of the soot blower. When the boiler load is reduced from 100% BMCR to 50% BMCR, the average inlet flue gas temperature of the corrugated plates is reduced by 44.2 K; however, when the soot-blowing steam temperature varies by 20 K, the average inlet flue gas temperature of the corrugated plates varies by only about 1.8 K. It means that it is difficult to enhance the cold end flue gas temperature of the corrugated plates only by raising the soot-blowing steam temperature at low boiler load. Adding a soot blower using high-temperature steam or hot air at the outlet of the corrugated plates may be an option to solve the ash deposition of the corrugated plates.

Study on the propagation characteristics of shockwave in dense crowd in corner passage

Crowd shockwaves are prone to occur when evacuating dense crowds, especially in areas with corner passages, leading to congestion and accidents. The characteristics of shockwaves in corner passages need further exploration. This study used AnyLogic software based on the social force model to construct scenarios. The propagation mechanism of crowd shockwaves was revealed through simulation analysis of the changes in wave amplitude, duration, and propagation velocity of crowd density waves under different corner angles (0–90°). It was found that a 45° corner passage has advantages compared to other corner passages for evacuation. At higher desired velocities, pedestrians form a bottleneck-like area at the corner of the passage, resulting in crowd shockwaves. Because of social forces, congestion occurs primarily in the corner area. To alleviate this pressure, pedestrians actively adjust the distance between themselves and others. The time interval between the two shockwaves decreases as the desired velocity increases. The propagation time of crowd shockwaves before the corner is generally more significant than the duration after the corner. This study could guide the elimination or reduction of crowd shockwaves, improving pedestrians' evacuation efficiency and safety in evacuation passages.

Hydrodynamic Modelling in a Mediterranean Coastal Lagoon—The Case of the Stagnone Lagoon, Marsala

Coastal lagoons are important wetland sites for migratory species and the local flora and fauna population. The Stagnone Lagoon is a coastal lagoon located on the west edge of Sicily between the towns of Marsala and Trapani. The area is characterized by salt-harvesting plants and several archaeological sites and is affected by microtidal excursion. Two mouths allow exchange with the open sea: one smaller and shallower in the north and one larger and deeper in the south. This study aims to understand the lagoon’s hydrodynamics, in terms of circulation and involved forces. The circulation process appears to be dominated mainly by tide excursions and wind forces. Wind velocity, water levels, and water velocity were recorded during different field campaigns in order to obtain a benchmark value. The hydrodynamic circulation has been studied with a 2DH (two-dimensional in the horizontal plane) unstructured mesh model, calibrated with data collected during the 2006 field campaign and validated with the data of the 2007 campaign. Rapid changes in averaged velocity have been found both in Vx and Vy components, showing the strong dependence on seiches. This study tries to identify the main factor that domains the evolution of the water circulation. Sensitivity analyses were conducted to estimate the correct energy transfer between the forcing factors and dissipating ones. A Gauckler–Strickler roughness coefficient between 20 and 25 m1/3/s is found to be the most representative in the lagoon. To enhance the knowledge of this peculiar lagoon, the MIKE 21 model has been used, reproducing all the external factors involved in the circulation process. Nash–Sutcliffe coefficient of efficiency (NSE) values up to 0.92 and 0.79 are reached with a Gauckler–Strickler coefficient equal to 20 m1/3/s related to water depth and the Vy velocity component. The Vx velocity component NSE has never been satisfying, showing the limits of the 2D approach in reproducing the currents induced by local morphological peculiarities. Comparing the NSE value of water depth, there is a loss of up to 70% in model predictivity capability between the southern and the northern lagoon areas. This study aims to support the local decision-makers to improve the management of the lagoon itself.

Theoretical and experimental modeling of geodynamiс processes in uplift slopes

The flow structure created in a viscous medium at a constant inclination angle of the free surface of the uplift slope is analyzed. The velocity field in a high-viscosity uplift slope is determined under conditions of a horizontal pressure gradient. This pressure gradient occurs when the slope height decreases with distance from the main ridge. With a constant dynamic viscosity of the uplift slope, the flow velocity in it decreases with distance from the axis of the main ridge. In this case, the uplift slope is in conditions of compressive stresses, the consequence of which are thrusts and compression folds. Tensile stresses in the uplift slope exist with an increase in the flow velocity in the layer with distance from the main ridge axis. The flow velocity increases with decreasing viscosity of the layer with distance from the main ridge. The viscosity distribution on the base of the uplift slope at a distance from the axis of the main ridge is determined using the tension condition in the uplift slope. Expressions are presented for the forces causing the formation of a disruption between the blocks of the uplift slope. The magnitudes of these forces are estimated. A relation representing the condition for the formation of a disruption between the blocks is obtained. The formation of disruptions is governed by the change in viscosity along the uplift slope and the change in the flow velocity in it. When the disruption between the uplift slope is formed, free vertical boundaries of the blocks appear. The motion of a highly viscous liquid during the formation of a free vertical boundary of the block has been studied experimentally when the liquid flows out from a rectangular vessel. The experiments have revealed two outflow regimes: (i) the regime of constant thickness of the liquid layer; (ii) the regime of decreasing layer thickness. On the basis of experimental modeling the time of the first period after the formation of the slope rupture and the formation of the free volume between the blocks is estimated. During this period the height of the layer (slope) is practically constant and the layer length increases. The process of filling the free volume between the blocks with a high-viscosity slope material is considered. As the modeling shows, the filling rate of the free volume between the diverging blocks of the uplift slope is much higher than the formation rate of the free volume between these blocks. The parameters of the uplift slope blocks are determined. Among these parameters are block viscosity, slope height, flow velocity and forces acting on the blocks. The time-varying structure of the surface of the uplift slope is presented. There is a qualitative correspondence between the modeling results and the profile of the uplift slope for the north-western Caucasus.

Research on the impact of overflow well shut-in on wellbore integrity and safety

If an overflow occurs, the well must be closed immediately. To ensure the safety of the drilling wellbore in ultra-deep wells, it is critical to analyze the transient flow process and pressure fluctuations of the fluid in the annular space of the overflow well shut-in. This paper investigates the pressure fluctuation model of multi-phase fluid in the annular space after overflow occurs during gas well drilling, analyzes the influence factors of multi-phase fluid's pressure wave velocity, and simulates and analyses pressure fluctuation changes in the annular space in light of the impact of overflow well shut-in on wellbore safety. The model's correctness is verified by comparing it to experimental data published in the literature. The model is developed and examined using the example of a genuine gas well in western China. According to the study, as soon as the BOP closes, pressure rapidly increases to a high of 6.09 MPa at 5.89 s before falling to a valley of 4.68 MPa at 35.36 s. When the mild shut-in time lasts 20 s, the wellhead annular pressure reaches a maximum of 5.8 MPa. If the wellhead equipment can withstand the annular space's first pressure wave, a hard shut-in is recommended. To optimize the overflow well shut-in system and ensure wellbore safety, the change in pressure in the wellhead annular space as a result of varied shut-in timings and drilling fluid displacement is studied.

Preparation of protective coatings for the leading edge of wind turbine blades and investigation of their water droplet erosion behavior

The damage caused by rain droplet erosion to the leading edge of wind turbine blades is extremely severe. To reduce this issue, in this study, hydroxyl-terminated polybutadiene (HTPB) and isophorone diisocyanate (IPDI) were used as the polyurethane (PU) polyol and curing agent, respectively, to prepare a PU coating with a high resistance to water droplet erosion (WDE) for the protection of the leading edge of wind turbine blades. The effect of n (–NCO):n (–OH) (R-value, n is the molar ratio) on the mechanical properties and WDE resistance of PU coatings, the relationship between the two performances, and the influence of the erosion conditions on the WDE behavior were investigated for the first time. The results show the existence of a correlation between the mechanical properties (hardness, impact, flexibility, and tensile strength) and WDE resistance of the coating. While, a better abrasion resistance is found not to result in a better WDE resistance. The PU coating with an R-value of 1.2 shows an optimal WDE resistance in both atomization and jet erosion experiments. In atomized droplet erosion (ADE) experiments, the change in erosion velocity accelerates the incubation period of coating erosion damage and increases the erosion rate. In jet droplet erosion (JDE) experiments, the damage to the coating is closely related to the erosion angle, reaching a maximum at an impact angle of 60°. Furthermore, in the ADE experiments, various erosion morphologies, such as pits, grooves, cracks, and stepped texture, are observed on the damaged coating surface. While, regarding the JDE experiments, holes, grooves, and cracks are observed. Such damage is caused by the combined effects of water hammer pressure, lateral jets, and local permeation.

Numerical Simulation and Experimental Research of Spatial Volume Distribution and Velocity Changes of Abrasive Suspension Jet Based on LES + VOF + DEM

The machining accuracy and cutting ability of abrasive suspension jet (ASJ) are affected by the spatial volume distribution and velocity changes of jet flow and abrasives in the free jet area outside the nozzle. In this paper, large eddy simulation (LES) flow model, volume of fluid (VOF) multiphase flow model and discrete element model (DEM) were used to simulate the flow field characteristics of ASJ. The spatial volume distribution and velocity changes of jet flow and abrasives under 10[Formula: see text]MPa jet pressure were studied and the model validation experiments were carried out. In the comparison between the numerical simulation results and the experimental results, it was found that the average error of the percentage of central jet flow is 3.4%, the percentage of central abrasive particles is 3.0% and the velocity of abrasive particles is 4.2%. The physical structure of the numerical model is fixed (so it does not support abrasive injection jet (AIJ)), and the material physical parameters, initial conditions and boundary conditions are editable. Therefore, it can be used to predict the degree of water divergence, abrasives divergence and abrasives velocity attenuation of ASJ with different jet pressure and abrasive types. This numerical model can provide guidance for the parameter setting of ASJ machining process in order to obtain better machining accuracy and cutting ability.

Effect of Positional Changes on Cerebral Perfusion in Parkinson's Disease Patients With Orthostatic Hypotension.

Orthostatic hypotension (OH) is one of the most common autonomic dysfunctions in Parkinson's disease (PD) patients. However, many patients with OH are asymptomatic. Conversely, orthostatic dizziness (OD) is not always associated with OH. We investigated the effects of positional changes on cerebral perfusion in patients with PD and OH. We enrolled 42 patients, comprising 31 PD patients and 11 healthy controls. All the subjects underwent the following clinical assessments: the OH questionnaire, head-up tilt test (HUTT) with transcranial Doppler (TCD), near-infrared spectroscopy, measurement of the change in oxygenated hemoglobin (ΔHboxy) during the squat-to-stand test (SST), measurement of the time derivative of total hemoglobin (DHbtot), and time taken to reach the peak (peak time [PT]) of DHbtot after restanding. The mean flow velocity change (ΔMFV) in the TCD during the HUTT failed to differentiate between the PD-OH(+) and PD-OH(-) groups. The change in oxygenated hemoglobin ΔHboxy was greater in the PD-OH(+) group, which persisted for 9 min until the end of the HUTT only in the left hemisphere. During SST, PT was significantly delayed in the left hemisphere in PD-OH(+) patients. Although TCD demonstrated no significant difference in ΔMFV, the parameters measured by near-infrared spectroscopy, such as ΔHboxy during HUTT and PT during the SST, significantly increased ΔHboxy or delayed PT in the left hemisphere of PD-OH(+). Positional changes have a detrimental effect on cerebral hemodynamics in patients with PD and OH, especially in the left hemisphere.

Wetting and Dewetting Behaviors of Droplets on the Nanoring Surface

AbstractThis study uses molecular dynamics simulations to investigate the wetting behavior of water droplets on a gold substrate with annular grooves. The research finds that droplet size and substrate hydrophilicity similarly affect wetting behavior. Enhanced hydrophilicity changes the velocity trend of droplet contact line movement, while droplet size impacts the magnitude of velocity change. Contact angle fluctuations are observed and analyzed theoretically based on Young's equation. The results provide insights into the relationship between droplet dynamics and surface structure, contributing to a better understanding of wetting processes at the microscopic level.

Cerebrovascular hemodynamics association with brain structure and function in Multiple Sclerosis

BackgroundVascular risk factors seem to contribute to disease progression in Multiple Sclerosis (MS), but the mechanistic connection between vascular risk and MS is unknown. Understanding cerebrovascular hemodynamics (CVH) in MS may help advance our understanding of the link between vascular risk and MS. ObjectivesExamine the relationship between CVH [dynamic cerebral autoregulation (dCA) and vasoreactivity (VR)] and brain structure (MRI) and function (cognition, and gait) in individuals with MS. MethodsTranscranial Doppler ultrasound (TCD) was utilized to assess two key markers of CVH: dCA and VR. dCA (reported as phase and gain) is calculated from the spontaneous blood pressure and flow velocity oscillations. VR is calculated as the slope of change in cerebral blood flow velocity in response to end-tidal CO2. Global gray matter (GM), white matter (WM), WM hyperintensity (WMH) volumes and WM lesion counts were measured from brain MRI. All participants underwent detailed cognitive and gait assessments. ResultsEighty participants were included (age 44 ± 11, 26 % male); 75 had relapsing-remitting MS (94 %), with disease duration of 8 (11) years [median (IQR)] since MS diagnosis and an Expanded Disability Status Scale (EDSS) of 2.0 (4.0). Higher phase (better dCA) was associated with greater GM volume, lower WHM burden and higher cognitive scores in the memory and global cognitive domains (all P values <0.05). There was no relationship between CVH and gait speed in our study participants. There was no relationship between VR and any measures of brain structure and function. ConclusionsMore efficient cerebral autoregulation is associated with better brain structure (larger GM and lower WMH volumes) and function (cognition, but not gait) in patients with MS.

Tangzu granule alleviate neuroinflammation in diabetic peripheral neuropathy by suppressing pyroptosis through P2X7R /NLRP3 signaling pathway

Ethnopharmacological relevanceDiabetic peripheral neuropathy (DPN) is a common complication of diabetes mellitus, mainly manifested as paresthesia. Tangzu granule (TZG) is derived from famous traditional Chinese medicine decoctions and optimized by long-term temporary practice. TZG has good efficacy in improving numbness, pain and pruritus of the lower extremities of DPN patients. However, the overall regulatory mechanisms underlying its effects on DPN remain unclear. Aim of the studyThis study aims to explore the potential mechanism of TZG for treating DPN. Materials and methodsSprague-Dawley (SD) rats were used to establish an in vivo model of DPN with streptozotocin (STZ) injection and high-fat diet (HFD) feeding. Additionally, sciatic glial RSC96 cells were induced with high glucose in vitro. SD rats in intervention group received TZG treatment for 12 weeks. After 12 weeks of treatment, sciatic nerve function was evaluated by intelligent hot plate meter and neuro electrophysiology detector. The morphological changes of sciatic nerve cells were observed by hematoxylin-eosin staining and transmission electron microscope. IL-1β, IL-18 inflammatory cytokines, pyroptosis and P2X7R/NLRP3 signaling pathway were observed by Western blotting, immunofluorescence staining and ELISA. ResultsTZG improved nerve conduction velocity and sciatic neuropathy rational structural changes in DPN rats. It also inhibited RSC96 inflammatory response and cell death that induced by high glucose. This may be related to TZG inhibiting P2X7R, decreasing the activation of NLRP3 inflammasomes, down-regulating the levels of pyroptosis proteins such as caspase-1, cleaved caspase-1, gasdermin D (GSDMD), and GSDMD-N, and inhibiting the release of interleuki (IL)-18 and IL-1β inflammatory cytokines. ConclusionsTZG inhibited pyroptosis through P2X7R/NLRP3 signaling pathway, alleviated neuroinflammation, and showed protective effect in the treatment of DPN.

Analisis Deformasi di Lampung dan Selat Sunda berdasarkan Data GNSS tahun 2018 hingga 2021

The Lampung Province and Sunda Strait have a seismic gap zone with the potential for major earthquakes in the future. This study analyzes the deformation occurring in this region using continuous Global Navigation Satellite System (GNSS) station data from Indonesia Continuously Operating Reference Station (InaCORS) and Sumatran GPS Array (SuGAr) from 2018 to 2021.5. The GNSS data was processed using the Bernese 5.2 scientific software, applying least squares for velocity changes and statistical tests to analyze significance. The data processing was carried out in two schemes: the first scheme covering 2018-2020, and the second covering 2019-2021. The results of the deformation analysis from 2018 to 2021, using two continuous GNSS data processing schemes, showed velocity changes relative to the Sundaland Plate ranging from ~2 mm/year to ~20 mm/year. In the eastern region of the Sumatra fault, the velocity changes were smaller, around ~5 mm/year, due to the minimal influence of tectonic activity. However, in the Sunda Strait region, the deformation was influenced by volcanic activity. The deformation occurring in Lampung Province and the Sunda Strait, based on GNSS velocity changes, significantly contributes to tectonic and volcanic activities.