Flow Algorithm Research Articles (Page 1)

The aim of this study is to evaluate a deep variational network, FlowVN, for the reconstruction of heavily undersampled 4D Flow MRI across multiple sites. FlowVN was trained on fully sampled 4D Flow MRI datasets of healthy volunteers from one site. The model was tested on retrospective undersampled data (R = 6-22) of six normal volunteers from the same site and six from another site, prospectively undersampled data (R = 12.4-13.8) of six healthy volunteers from the second site and six patients with aortic stenosis from first Site. Performance was evaluated using nRMSE, relative and angular error, average and maximum velocity, flow rate, volumetric flow, and turbulent kinetic energy (TKE), with a Wilcoxon signed-rank test to assess the difference from ground truth. FlowVN showed minimal sensitivity to the number of training datasets and performed well even when trained on a single dataset. FlowVN also demonstrated good generalizability across sites. No significant difference in average and maximum velocity was observed up to R = 16. Total TKE was preserved up to R = 10 in the normal volunteers, but was well preserved even at higher acceleration factors in the aortic stenosis patients. Flow volumes through the ascending and descending aorta were well preserved for all acceleration factors, although ascending aorta flow volumes for data from one site were significantly different from ground truth for AF > 16. FlowVN accurately reconstructs highly undersampled 4D Flow MRI from multiple sites using a model trained on a single dataset, maintaining excellent quantitative image quality even at very high acceleration factors.

A residual-coupled segregated algorithm for three-fluid flow in pipelines: Enhanced stability and computational efficiency

To compare the perioperative outcomes, efficacy, and safety of modified transurethral thulium laser enucleation-resection (ThuLERP) versus standard anatomic thulium laser enucleation (ThuLEP) for large-volume benign prostatic hyperplasia (BPH) (> 80 ml), with a primary focus on early urinary continence recovery. We retrospectively analyzed 215 patients with large-volume BPH treated between January 2021 and December 2024. Patients were segregated into the ThuLERP group (n = 110), receiving anatomical enucleation of the middle and lateral lobes combined with vaporization cutting at the prostatic apex and anterior commissure, or the ThuLEP group (n = 105), undergoing traditional 3-lobe anatomical enucleation. Baseline characteristics, including prostate volume (102.5 ± 21.3 ml vs 104.1 ± 22.5 ml), were comparable between groups. Primary outcomes assessed continence at 1 week, 1 month, and 3 months; secondary outcomes evaluated perioperative metrics and functional recovery at 6 months. All procedures were successful. The ThuLERP group demonstrated significantly shorter total operation time (65.2 ± 18.5 minutes vs 79.4 ± 20.1 minute, P < .01) and enucleation time (48.1 ± 15.3 minutes vs 62.5 ± 17.8 minutes, P < .01) compared to ThuLEP. Safety outcomes favored ThuLERP, showing a lower incidence of postoperative hematuria requiring intervention (6.4% vs 12.4%, P < .05) and no reoperations for bleeding in the ThuLERP group compared to 1.9% in the ThuLEP group, although this difference was not statistically significant (P > .05). Notably, ThuLERP resulted in superior early continence: incontinence rates were significantly lower at 1 week (8.2% vs 21.9%, P < .01) and 1 month (2.7% vs 9.5%, P < .05). By 3 months, continence rates were comparable (> 98%). Both groups achieved similar significant improvements in International Prostate Symptom Score, quality of life, maximum urinary flow rate, and post-void residual at 6 months. Modified ThuLERP is as effective as standard ThuLEP regarding long-term functional outcomes for large-volume BPH. However, it offers distinct advantages by reducing operative time, improving hemostasis, and significantly accelerating the recovery of early urinary continence.

To identify predictors of voiding impairment following transperineal prostate biopsy (TPPB) and evaluate the effect of alpha-blocker pretreatment: METHODS: A prospective observational study was conducted between June 2022 and May 2024, enrolling 279 patients undergoing TPPB. Patients were stratified into four groups according to the duration of alpha-blocker pretreatment. Baseline characteristics and voiding parameters were collected, including the international prostate symptom score (IPSS), quality of life, maximal flow rate (Qmax), and post-void residual urine. Follow-up assessments were performed at 7 and 30 days post-biopsy. The rate of voiding impairment and post-biopsy voiding parameters were compared across groups. Logistic regression analyses were conducted to identify independent predictors of post-biopsy voiding impairment. Baseline characteristics were comparable among all groups. At 7 days post-biopsy, patients with alpha-blocker pretreatment duration of < 12 months exhibited a lower voiding impairment rate, lower IPSS scores, and higher Qmax compared with patients without alpha-blocker pretreatment (p < 0.05). In contrast, patients with alpha-blocker pretreatment duration of > 12 months showed no differences in voiding impairment rate or voiding parameters compared to those without alpha-blocker pretreatment (p > 0.05). Logistic regression analyses demonstrated that diabetes mellitus (DM) was independently associated with post-biopsy voiding impairment, whereas alpha-blocker pretreatment for < 12 months exerted a protective effect (p < 0.01). TPPB is associated with voiding impairment. DM may serve as a predictor of post-biopsy voiding impairment, while alpha-blocker pretreatment for < 12 months may play a protective role.

Microphysiological systems (MPSs) have emerged as promising platforms for drug discovery and in vitro pharmacological testing. MPSs aid to reproduce physiologically relevant microenvironments, in which controlled perfusion can play important role. In this study, an on-chip AC electrothermal (ACET) pump was developed for pulsatile perfusion in microfluidic cell culture systems. The proposed pump generates fluid motion through the interaction between an applied electric field and temperature-dependent gradients in the electrical properties of the fluid. Pulsatile perfusion was produced by periodic application of an AC voltage to the electrode array, and the pulsation cycle could be controlled electrically. The maximum flow velocity increased with the applied AC voltage, demonstrating tunable flow generation by the ACET pump. To evaluate the applicability of the developed system to cell culture, human mesenchymal stem cells (hMSCs) were cultured under pulsatile perfusion conditions for five days. The results showed that osteogenic differentiation under pulsatile perfusion was higher than that under static culture conditions. These findings demonstrate the potential of the proposed on-chip ACET pump as a simple and effective platform for generating physiologically relevant pulsatile perfusion in microphysiological systems.

This study aimed to evaluate the diagnostic value of pressure-flow study parameters in female patients with anatomical bladder outlet obstruction (BOO) and to investigate the association between obstruction location and urodynamic findings. A total of 72 women with anatomical BOO who underwent urodynamic examination between January 2007 and October 2023 were retrospectively analyzed. Based on obstruction location, patients were categorized into 3 groups: external urethral meatus stenosis (n=18), urethral stricture (n=49), and bladder neck obstruction (n=5). Urodynamic assessments included free-flow maximum flow rate (Qmax), postvoid residual urine volume, filling cystometry, and a pressure-flow study. Statistically significant differences were observed between groups in free-flow Qmax, urethral caliber, and pressure-flow parameters. Bladder Outlet Obstruction Index - Female, Dybowski index, urethral resistance factor, obstruction coefficient (OCO), and Woman Obstruction Index values were significantly higher in the urethral stricture group than in the other groups (P=0.022, P=0.025, P=0.031, P=0.031, and P=0.031, respectively). The Blaivas-Groutz nomogram classified all patients as obstructed, regardless of obstruction location. Diagnostic accuracy exceeded 90% when using the Barco-Castillo, Dybowski, and OCO indices; however, the accuracy varied by obstruction location. In women with anatomical BOO, the diagnostic performance of pressure-flow studies varies by the anatomical location of the obstruction. While urethral strictures yield high diagnostic rates, external urethral meatus stenosis may be underdiagnosed by urodynamic assessment alone. This variability remains a challenge in standardizing BOO diagnosis in women.

While omalizumab has demonstrated clinical efficacy in severe allergic asthma, its impact on small airway function and structural changes remains underexplored. We aimed to evaluate the multidimensional effects of omalizumab using physiological, symptomatic, and quantitative CT (QCT) measures. This prospective observational study included 25 patients with severe allergic asthma treated with omalizumab for 16 weeks. Assessments included blood eosinophils, fractional exhaled nitric oxide (FeNO), spirometry, body plethysmography, Asthma Control Test (ACT), modified Medical Research Council (mMRC) dyspnea scale, 6-minute walk test (6MWT), inspiratory and expiratory quantitative computed tomography (QCT) scans. Changes before and after treatment were analyzed using paired Student’s t-tests, and Pearson’s correlation was used to explore inter-domain relationships. After 16 weeks of omalizumab treatment, patients showed significant reductions in airway inflammation, with Eosinophil counts showing a downward trend. FeNO decreasing from 69.3 ± 33.3 to 44.8 ± 23.8 ppb (p < 0.001). Maximal expiratory flow at 50% of forced vital capacity (MEF₅₀) increased from 1.89 ± 1.31 to 2.20 ± 1.19 L/s (p = 0.001), and maximal expiratory flow at 25% of forced vital capacity (MEF₂₅) increased from 0.61 ± 0.41 to 0.75 ± 0.52 L/s (p = 0.002). The residual volume/total lung capacity (RV/TLC) ratio decreased from 48.7 ± 10.2% to 41.7 ± 9.3% (p < 0.001). Asthma Control Test (ACT) scores improved from 17.4 ± 0.8 to 20.3 ± 1.2 (p < 0.001). Physical capacity increased, with 6MWT from 296.3 ± 54.5 to 327.9 ± 54.1 m (p < 0.001). QCT revealed a significant reduction in expiratory gas trapping volume from 382.4 ± 248.7 to 285.4 ± 176.1 mL (p = 0.004). Omalizumab was associated with short-term (16-week) improvements in type 2 inflammatory markers, pulmonary function, symptom control, and QCT-derived structural measures in patients with severe allergic asthma. QCT imaging showed reduced gas trapping over 16 weeks, suggesting that quantitative imaging may complement symptom-based assessment of biologic response. However, larger studies with longer follow-up are also needed to confirm the durability of these changes and their long-term clinical relevance.

Abstract The Evershed flow (EF), since its discovery in 1909, represents a longstanding issue in solar physics, with its three-dimensional velocity fields and underlying physical mechanisms still not fully understood. We present a comprehensive analysis of the velocity fields for 20 sunspots, using the full-disk spectroscopic observations from the Chinese H α Solar Explorer (CHASE). The height-dependent velocity fields are derived from the bisector analysis of the Si i 6560.58 Å, Fe i 6569.21 Å, and H α 6562.81 Å spectral lines, which are formed from the deep photosphere (∼70 km) to the upper chromosphere (∼1340 km). The statistical results based on CHASE observations reveal that the photospheric EF manifests as a nearly horizontal outflow with the maximum radial flow velocities of 2.5–2.9 km s −1 at the outer penumbral boundaries, and the inverse EF (IEF) at the chromosphere shows predominant inward flows of 1.6–3.5 km s −1 , with substantial downward flows. EF-like flows above the penumbra are found in all sunspots in the H α far wings, with a velocity reversal shown by the bisector analysis at H α ±0.65 Å (corresponding to a normalized line depth intensity of ∼0.6) in the limb-side region, and a small reversal in the center-side region, suggesting the coexistence of the EF outflows and IEF downflows at the flow reversal layers. We finally construct a three-dimensional schematic of the EF and IEF above sunspots, depicting the height-dependent flows from the deep photosphere to the upper chromosphere.

Comparative analysis of numerical algorithms for modeling complex solid-liquid flow in a vertical conveying system with ceramic and expanded polystyrene particles

We present a reference-free computational wavefront sensor based on binary amplitude modulation and phase retrieval. The method employs a Digital Micromirror Device as a programmable amplitude modulator and reconstructs the complex optical field from multiple far-field intensity measurements using the Reweighted Amplitude Flow algorithm with Optimal Spectral Initialization. Unlike classical pupil-plane wavefront sensors, the proposed architecture contains no wavelength-specific optical elements, enabling straightforward adaptation across a broad spectral range. The achievable spatial resolution of the reconstructed wavefront scales directly with the modulator resolution. We experimentally demonstrate wavefront reconstruction at 650 nm and at 2116 nm, a wavelength regime where commercial wavefront sensors are scarce. At 650 nm, the reconstructed wavefront is validated against a commercial lateral shearing interferometer, and the sensor is further integrated into a closed-loop adaptive optics system using a deformable mirror. The proposed approach is particularly suited for applications requiring high spatial resolution and large dynamic range in slowly varying or quasi-static laser fields, where computational reconstruction speed is not a primary concern.

Next-generation FVIIIa-mimetic bispecific antibody NXT007: evaluation in preclinical models of hemostasis and thrombosis.

Sediment accumulation in the drainage systems of mountain tunnels is a typical issue threatening operational safety. To explore the sedimentation behavior under the coupling of multiple factors, this study systematically analyzes the coupled effects of sediment content, flow rate, slope, and cross-sectional shape on sedimentation through full-scale experiments and numerical simulations. The results indicate that: (1) the sediment accumulation is linearly positively correlated with sediment concentration (fitting slope of 0.87) and exponentially negatively correlated with flow rate and slope (R2 &gt; 0.90); (2) for drainage trenches with different cross-sectional shapes under the same boundary conditions, the maximum flow velocity and anti-sedimentation capacity rank as narrow rectangular &gt; semi-circular ≈ inverted trapezoidal &gt; rectangular; (3) the study proposes engineering anti-sedimentation strategies, such as moderately increasing the slope and adopting a periodic concentrated discharge model to enhance sediment transport capacity using peak flow; (4) under the premise of meeting drainage and flood control standards, the inverted trapezoidal or semi-circular cross-sections are preferred. The bottom waterway width can be reduced to increase flow velocity, thereby achieving a synergistic optimization of drainage efficiency and operational reliability. This provides a quantitative basis for the structural selection and anti-sedimentation design of tunnel drainage systems.

Transperineal prostate biopsy (TP-Bx) is increasingly preferred due to its lower infection risk and improved clinically significant prostate cancer detection rates. Its feasibility under local anesthesia provides both clinical and economic advantages. However, acute urinary retention (AUR) remains a significant post-procedure concern. This study aims to evaluate the impact of transperineal prostate biopsy performed under local anesthesia on voiding function using uroflowmetry parameters. A prospective observational study was conducted with 74 patients. TP-Bx was performed under local anesthesia using a freehand technique. Uroflowmetry parameters, including maximum urinary flow rate (Qmax, mL/s), average urinary flow rate (Qave, mL/s), voided volume (Vv, mL), and post-void residual volume (PVR), were assessed before and after the procedure to evaluate its impact on voiding function. The average changes in Qmax and Qave between pre and post procedure were 1.78 ± 4.33 and 0.63 ± 1.70, respectively. A significant reduction in Qmax and Qave was observed after TP-Bx (p < 0.001). PVR increased after TP-Bx (p < 0.001); however, these changes were mild and did not require catheterization. With increasing experience, TP-Bx has become safer. The use of local anesthesia reduces anesthesia-related complications, and the historically feared risk of AUR appears lower than previously assumed. These findings support TP-Bx as a safe and effective diagnostic approach.

This study aimed to evaluate the prevalence and risk factors of small airway dysfunction (SAD) in patients with pneumoconiosis and to emphasize its role in early stage and disease monitoring. Data including demographics, ILO pneumoconiosis classification, and pulmonary function tests were analyzed. SAD was defined by at least two pulmonary function parameters—maximal mid-expiratory flow (MMEF), forced expiratory flow at 50% (FEF50), and 75% (FEF75)—below 65% of predicted values. SAD was identified in 59% of patients (n = 118). Compared to stage 1, the risk of SAD was fourfold higher in stage 2 (p = 0.037, OR = 4.119) and nearly 14-fold higher in stage 3 pneumoconiosis (p = 0.008, OR = 13.714). Progressive massive fibrosis increased SAD risk by nearly seven times (p = 0.010, OR = 6.884). These results highlight that SAD is common and may occur early in pneumoconiosis, underscoring its importance in patient monitoring protocols.

Velocity measurement from schlieren images of subsonic flows using a wavelet-based optical flow algorithm

The International Geomagnetic Reference Field (IGRF) model is a series of models that describe the large scale magnetic field measured at the Earth's surface. It is used by a wide range of scientists and industries, including in navigation, space weather applications, and resource exploration. The 14th generation, IGRF-14, is the result of an international collaboration over 19 different lead research groups. This new generation provides a definitive model of the main magnetic field (MF) for the epoch 2020.0, a prediction of the MF for 2025.0, and a predicted average annual time variation of the magnetic field for 2025.0 2030.0. The first time derivative of the magnetic field, known as secular variation, (SV) is linked to the flow at the top of Earth's outer core. As such, the ensemble of IGRF-14 candidate models can be used to investigate predicted core flow variability between 2020.0 and 2030.0. We use the pygeodyn Python package using the AR-1 'dense' methodology, the 71% geodynamo prior, and keep all inversion parameters fixed to ensure that differences in inferred flow arise solely from variations from the IGRF candidate models. Our results demonstrate that while all candidates produce broadly similar flow spectra for all degrees, candidates that deviate most from the median IGRF model also show the largest differences in flow. In all cases, the flow speed difference remains below 25% of the maximum flow speed of the Huber-weighted mean model in space, with most discrepancies occurring at small spatial scales. The greatest flow uncertainty appears over the Pacific and in the polar regions, where constraints are weaker. Finally, we assess the impact of the maximum spherical harmonic degree truncation of the SV candidate models by comparing two SV candidates truncated at spherical harmonic degree 13 instead of 8. Increasing the truncation degree of SV alters the flow spectral energy at all degrees and increases the maximum flow speed by up to 31%, despite the flow maps remaining highly correlated. This study supports the idea of raising the spherical harmonic truncation degree to 13 for the SV predictioncomponent of theIGRF.

Abstract The one-way model of quantum computation is an alternative to the circuit model. A one-way computation is driven entirely by successive adaptive measurements of a pre-prepared entangled resource state. For each measurement, only one outcome is desired; hence a fundamental question is whether some intended measurement scheme can be performed in a robustly deterministic way. So-called flow structures witness robust determinism by providing instructions for correcting undesired outcomes. Pauli flow is one of the broadest of these structures and has been studied extensively. It is known how to find flow structures in polynomial time when they exist; nevertheless, their lengthy and complex definitions often hinder working with them. We simplify these definitions by providing a new algebraic formulation of Pauli flow. This involves defining two matrices arising from the adjacency matrix of the underlying graph: the flow-demand matrix M and the order-demand matrix N . We show that Pauli flow exists if and only if there is a right inverse C of M such that the product NC forms the adjacency matrix of a directed acyclic graph. From the newly defined algebraic formulation, we obtain O ( n 3 ) algorithms for finding Pauli flow, improving on the previous O ( n 4 ) bound for finding generalised flow, a weaker variant of flow, and O ( n 5 ) bound for finding Pauli flow. We also introduce a first lower bound for the Pauli flow-finding problem, by linking it to the matrix invertibility and multiplication problems over F 2 .

This study aims to analyze the impact of side friction on traffic performance along MP Mangkunegara Street, Palembang City, using the PKJI 2023 method and the Greenshields model. Observed side friction factors include parked/stopped vehicles, pedestrians, entering/exiting vehicles, and street vendors, with a very high intensity reaching 811.8 events/hour on Saturday and 890.4 events/hour on Tuesday. These conditions contribute to a significant reduction in free-flow speed and road capacity. Based on the Greenshields model analysis, the free-flow speed (Vf) decreased significantly from 38.833 km/h to 26.028 km/h, while the jam density (Dj) increased from 69.90 smp/km to 158.128 smp/km. Although the maximum flow (Qmax) increased due to rising density, the speed at maximum capacity declined. The peak-hour degree of saturation ranged from 0.44 to 0.78, indicating a level of service between B and D.

In this paper we propose an approach for automatically building real-time emulations of large scale cyber-physical energy systems. An end-to-end methodology is presented, starting from the system description, continuing with automatic model and interface generation, and finally completing with deployment and real-time execution. The intended target use of the proposed solution is the validation of massively distributed smart-grid software applications. The goal is to provide an automated testing framework that can be integrated in modern software development tool-chains. In this manner, complex software ecosystems that act on critical infrastructure can be exhaustively evaluated and validated before being deployed in the field. <p xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">A prototypical implementation is also presented. This relies on a commercially available real-time simulator whose digital interfacing capabilities were extended in order to meet our automation requirements. As a showcase we consider the problem of generator dispatch using a distributed optimal power flow algorithm. For this example application we consider two test scenarios: one consisting of a smaller network where 13 software agents are deployed, and a larger one involving 123 software agents. Using the proposed framework, scaling the test setup is automated, considerably reducing the required time and errors that typically appear during this process.

Background. Benign obstructive jaundice (BOJ) remains one of the most pressing problems in modern surgery and radiology. The increasing incidence of cholelithiasis, the growing number of surgical interventions on the biliary tract, and the associated iatrogenic injuries to the biliary system contribute to the high prevalence of this pathology. Timely diagnosis and selection of optimal treatment strategies largely determine the prognosis and quality of life for patients. Objective: to improve the outcomes of comprehensive treatment of patients with obstructive jaundice through the priority application of minimally invasive technologies based on modern radiological diagnostic methods. Materials and Methods. The study included 428 patients with obstructive jaundice treated from 2015 to 2024 at the Departments of Surgical Diseases and Radiology of Samarkand State Medical University based at the multidisciplinary clinic of SamSMU. All patients underwent comprehensive clinical, laboratory, and instrumental examination, including ultrasound with Doppler imaging, magnetic resonance cholangiopancreatography, endoscopic retrograde cholangiopancreatography, and percutaneous transhepatic cholangiography. Results. A comprehensive diagnostic algorithm was developed to determine the etiology of obstructive jaundice and the degree of hepatic insufficiency. Doppler studies revealed a significant decrease in maximum blood flow velocity in the portal vein by 1.3 and 1.7 times in obstructive jaundice class B and C, respectively. The application of differentiated surgical tactics using minimally invasive decompressive interventions contributed to a reduction in the rate of postoperative complications from 26.6% to 19.5% and mortality from 6.5% to 4.05%. Conclusion. A comprehensive approach to diagnosing obstructive jaundice using modern radiological methods and a differentiated treatment strategy with priority use of minimally invasive technologies can improve treatment outcomes for this category of patients.