Search Results (46)

Electrical storm (ES) is a life-threatening clinical condition characterized by recurrent ventricular arrhythmias within a 24 h period, carrying a high mortality rate. Despite conventional therapies, including hemodynamic optimization, antiarrhythmic drugs, implantable cardioverter-defibrillator (ICD) reprogramming, and catheter ablation, a subset of patients develop refractory ventricular arrhythmias. In this setting, cardiac sympathetic neuromodulation can interrupt arrhythmic circuits by reducing efferent sympathetic outflow to the myocardium. Stellate ganglion block (SGB) with local anaesthetic (LA) is a temporary pharmacological blockade used as rescue therapy; in the largest prospective series (the STAR study), 92% of treated patients achieved at least a 50% reduction in arrhythmic events in the 12 h following the procedure. Because the effect of anaesthetic blockade is transient, more durable interventions have been explored, including percutaneous radiofrequency or chemical neurolysis and surgical cardiac sympathetic denervation (CSD), although current evidence is largely confined to small, uncontrolled case series. This narrative review synthesizes the available evidence on cardiac sympathetic neuromodulation—spanning SGB, percutaneous neurolysis, and surgical CSD—in refractory ES, positioning these interventions primarily as a means of stabilizing patients and bridging to definitive therapy rather than as established survival-modifying treatments. Furthermore, this review describes the primary anatomical foundations of the cervicothoracic sympathetic nervous system and the various techniques for SGB, along with their most relevant clinical indications. The risks and complications associated with these interventions are also addressed. Finally, clinical implications and potential future research directions in this field are discussed, with the aim of providing guidance for the comprehensive management of critically ill patients with refractory ES. Full article

To address the low efficiency and unclear internal loss mechanisms of azimuth waterjet propulsion (AWP) systems operating under shallow and complex flow conditions, this study investigates an AWP unit at 950 rpm with a thrust of 1.63 kN. Steady numerical simulations are conducted under mooring and low-speed conditions, focusing on thrust coefficient, impeller efficiency, pump efficiency, and diffuser flow characteristics, with comparisons to a conventional mixed-flow pump. The results show that the propeller hydraulic efficiency at the design condition is approximately 52%, significantly lower than the 80–93% typical of mixed-flow pumps. The diffuser contributes nearly 80% of the total hydraulic loss, dominated by secondary flow effects. From the perspective of radial equilibrium in the guide vanes, secondary flow development is closely linked to spanwise momentum non-uniformity and deviation from equilibrium. The inclined outflow from the impeller induces strong spanwise imbalance, while the nearly 180° turning in the diffuser suppresses conventional force terms and establishes a pressure-gradient-dominated inertial balance associated with streamline curvature. This mechanism drives transverse migration and entrainment, promoting the formation of counter-rotating vortex pairs and secondary flows. Four major vortex concentration regions are identified, where interactions between secondary flow and recirculation generate complex three-dimensional vortex structures, including induced and spiral separation vortices. These vortices locally block the flow passage, causing pressure fluctuations and energy dissipation. The mid-span region of the guide vanes is identified as the primary location of loss accumulation. These findings provide theoretical and engineering guidance for diffuser optimization in AWP systems. It should be noted that the present study is based solely on numerical simulations, and no experimental validation for the investigated AWP configuration is currently available. Future experimental studies are needed to further verify the predicted hydraulic performance and flow structures. Full article

Water scarcity is an increasingly urgent global challenge, prompting the development of new water purification technologies that surpass conventional solutions. Decentralized greywater treatment is emerging as a viable option for enhancing water reuse in multifunctional systems that contribute to microclimate regulation, cooling, and urban climate adaptation. In this context, water-storage mats have been identified as a form of decentralized, roof-based biofilter for greywater treatment. The aim of this study was to assess the performance of newly developed, innovative, bio-based textile mats and assess their effectiveness in treating pre-treated greywater from a canteen (CGW) with a high organic content, in both laboratory- and pilot-scale experiments. The findings from the lab-scale testing revealed that the mats made from polyethylene terephthalate (PET) nonwoven fabric materials had the highest water storage capacity and dried out more slowly in outdoor conditions than mats made from polylactide (PLA) spunbonded fabric and polyhydroxyalkanoate (PHA) spunbonded nonwoven fabric. The PET hydroentangled nonwoven fabric mat (PET-WS) performed better than the other sample mats in the lab-scale experiment, and also outperformed the PHA mat consistently in the pilot-scale experiment when treating CGW. Apparent reductions in the concentration of the macro-pollutant parameters were observed at the outflow of the PET-WS mat compared to the inflow (p < 0.05) at the pilot-scale. Mean concentration reductions were comparatively higher for the five-day biochemical oxygen demand (BOD₅), chemical oxygen demand (COD), total nitrogen (TN), and total suspended solids (TSS), with mean reductions of 64%, 54%, 39% and 60%, respectively. This indicated the superior treatment performance of the PET-WS mat compared to the PHA mat, with mean reductions of only 36%, 25%, 6%, and 32%, respectively. However, the lower E. coli counts of 1.1 and 0.5 log reduction for the PET-WS and PHA mats, respectively, indicated that an additional disinfection unit was necessary. The findings of this study may help to determine the performance, stability and reliability of using lightweight, nonwoven fabric mats to treat high-strength GW, which is currently considered as an intermediate treatment step. The study also provides recommendations for process optimization. Additional post-treatment steps are required to produce high-quality treated effluent for non-potable reuse, particularly in urban areas facing high water scarcity, provided that the relevant reuse regulations or discharge criteria are met. Full article

This study presents the development and field testing of a Pressurized Driving-Down Air Multilevel Sampler (PDA-MLS), an integrated groundwater sampling device designed for depth-discrete sampling in boreholes affected by floating non-aqueous phase liquids (NAPLs). Conventional sampling methods—such as low-flow pumps, bailers, and packer-isolated systems—often fail under these conditions due to limited accessibility, cross-contamination, or disturbance of the water column. The proposed system addresses these limitations through a controlled pressurized-gas actuation mechanism that transfers groundwater from multiple PTFE-membrane chambers installed at discrete depths. This configuration enables low-disturbance sampling below floating contaminant layers. The use of chemically inert materials (stainless steel and PTFE) minimizes sampling artifacts and ensures compatibility with volatile organic compound (VOC) analyses. A simplified hydraulic conceptual framework describing inflow, outflow, and pressure-driven displacement was developed to support purge-duration estimation and operational parameter definition. The device was tested in a 90 m deep fractured limestone aquifer contaminated by tetrachloroethylene (PCE), where floating hydrocarbons limited the applicability of conventional sampling techniques. Field testing showed stable discharge conditions (~145–160 mL/min), repeatable sampling cycles, and successful collection of depth-discrete groundwater samples under the investigated site conditions. No evidence of sampler-related hydrocarbon entrainment was observed in the collected samples within the analytical detection limits of the adopted laboratory methods. To the authors’ knowledge, the PDA-MLS represents one of the few groundwater sampling systems specifically designed to combine low-disturbance multilevel sampling with operation in wells affected by floating NAPL. These features make it a promising tool for environmental monitoring, high-resolution characterization of fractured aquifers, and long-term assessment of contaminated sites. Full article

This study develops an analytical and computational framework for coupled transient gas redistribution induced by simultaneous localized injection and withdrawal in transmission pipelines. The aim is to describe source–sink interactions within a single transmission system, unlike conventional approaches that treat inflow and outflow processes independently. The governing equations of one-dimensional non-stationary isothermal compressible gas flow are transformed into a diffusion-type formulation using Charny regularization. The pipeline is divided into three interacting regions connected through pressure-continuity and mass-flux coupling conditions. Closed-form Laplace-domain solutions are derived for the dimensionless pressure field, and a practical Laplace-domain approximation is used for computational evaluation of transient pressure profiles. The results reveal a characteristic balancing point separating injection-dominated and withdrawal-dominated regions and show rapid convergence toward a quasi-steady redistribution regime. A pressure-deviation-based objective function is introduced to evaluate hydraulic disturbance, and the optimization analysis shows that the minimum disturbance occurs under a near-balanced source–sink operating condition. The obtained pressure profiles, asymptotic behavior, and regional redistribution patterns confirm the physical consistency of the proposed model. The framework provides a mathematically interpretable basis for analyzing coupled redistribution dynamics, hydraulic stabilization, and asymptotic equilibrium in gas transmission systems. Full article

Cardiopulmonary exercise testing (CPET) is the reference method for the objective assessment of exercise capacity because it provides an integrated appraisal of cardiovascular, respiratory and metabolic responses to exertion. However, CPET alone quantifies the magnitude of functional impairment without fully resolving the central and peripheral mechanisms that determine exercise intolerance. The integration of CPET with exercise stress echocardiography and near-infrared spectroscopy (NIRS) has therefore emerged as a clinically relevant multimodal strategy. Stress echocardiography provides real-time information on ventricular reserve, filling pressures, pulmonary pressure response, valvular function, pulmonary congestion and dynamic outflow obstruction, whereas NIRS provides continuous insight into skeletal muscle oxygen delivery, extraction and utilization. This narrative review summarizes the physiological rationale, practical workflow, methodological limitations and clinical applications of combined CPET, stress echocardiography and NIRS across heart failure, pulmonary hypertension, peripheral artery disease, cardiomyopathies and sports cardiology. By linking systemic gas exchange, central hemodynamics and peripheral oxygen handling, this approach may move exercise evaluation from a descriptive measure of performance toward a mechanism-based framework for phenotyping, risk stratification and individualized therapeutic decision-making. Further studies are needed to harmonize protocols, validate reproducible multimodal indices and demonstrate incremental prognostic value over conventional testing. Full article

Background: Transcatheter mitral valve implantation (TMVI) represents an evolving therapeutic strategy for patients with severe mitral valve disease who are at high or prohibitive risk for conventional surgery. Since the first human implantation in 2012, multiple dedicated and adapted devices have entered clinical investigation, yet only one dedicated system—the Tendyne prosthesis (Abbott Structural)—holds regulatory approval. This systematic review evaluates the current landscape of available and emerging TMVI devices, examines the clinical outcome data, discusses key indications and limitations, analyses the role of computed tomography (CT) in predicting left ventricular outflow tract (LVOT) obstruction caused by the unopposed anterior mitral leaflet, and compares TMVI outcomes with conventional surgical mitral valve replacement (SMVR) in the specific context of severe mitral annular calcification (MAC). Methods: A systematic search of PubMed, EMBASE, Cochrane Central, and Web of Science was performed for studies published from January 2010 to March 2025 reporting outcomes of TMVI in native valve disease, valve-in-valve (ViV), valve-in-ring (ViR), or valve-in-MAC (ViMAC) procedures. Studies reporting CT-based LVOT planning, neo-LVOT quantification, and LVOT obstruction outcomes were specifically sought. Meta-analyses comparing TMVI with redo surgical mitral valve replacement were included. A total of 63 studies (n > 12,000 patients across all subgroups) were included in the qualitative synthesis; 28 studies were included in the quantitative synthesis. Results: Nine dedicated TMVI devices are currently under clinical investigation, with only Tendyne holding CE Mark and FDA approval. In ViV/ViR cohorts, TMVI was associated with significantly lower in-hospital mortality (OR 0.72, 95% CI 0.57–0.92; p = 0.008) and 30-day mortality (OR 0.49; p = 0.04) compared with redo SMVR, with no significant difference at one year (OR 1.03; p = 0.91). In ViMAC cohorts, 30-day mortality ranged from 14 to 24%, which was substantially higher than in the ViV outcomes. CT-based virtual simulation of the neo-LVOT area—the residual outflow tract created by anterior mitral leaflet displacement—is the most validated predictor of LVOT obstruction, with a threshold of ≤1.7 cm² yielding 96% sensitivity and 92% specificity. The LAMPOON technique (laceration of the anterior mitral leaflet to prevent outflow obstruction) has expanded the eligibility for patients who were previously excluded due to LVOT risk. Surgical MVR in severe MAC carries a median 30-day mortality of 6.3% (range 0–27.3%), while ViMAC TMVI with dedicated devices yields 6.8% 30-day mortality, without a definitive randomised comparison. Conclusions: TMVI offers a viable alternative to redo surgery in high-risk patients with failed bioprostheses or rings. In severe MAC, both surgical and transcatheter approaches carry significant risk; patient selection, CT-guided LVOT planning, and use of dedicated devices are critical to optimising outcomes. The ongoing SUMMIT randomised controlled trial will provide the first high-quality comparative data. Future developments in transseptal delivery and LVOT-safe device architectures are expected to broaden the eligible population. Full article

Degenerative mitral stenosis (MS) secondary to extensive mitral annular calcification (MAC) represents a growing clinical challenge in an aging population. These patients are often elderly, frail, and harbor a significant burden of comorbidities, rendering conventional mitral valve surgery prohibitively high-risk. While transcatheter mitral valve replacement (TMVR) has emerged as a potential alternative, the current evidence is only derived from single-arm observational registries. Therefore, the transition toward randomized controlled trials to define optimal patient selection and long-term prosthetic durability is necessary. This review examines the current landscape of TMVR for degenerative MS, focusing on the role of multimodal pre-procedural planning, procedural technique, and prevention of the principal complications. The integration of echocardiography and multi-slice computed tomography (MSCT) is essential for evaluating anatomical feasibility, particularly in predicting neo left ventricle outflow tract (neo-LVOT) obstruction, the primary determinant of procedural mortality. However, it is limited due to the absence of standardized protocol. We are showing the outcomes of off-label balloon-expandable aortic prostheses and dedicated TMVR system, which are the only two devices which data in patients with MS are available. Despite high technical success rates in specialized centers, complications, including paravalvular leak, valve thrombosis, and device migration, remain more prevalent than in aortic interventions. We present some tips and tricks to prevent and manage adverse events. TMVR represents a transformative frontier for inoperable patients with severe MAC. However, its routine clinical adoption requires further refinement of dedicated technologies and standardized imaging protocols to improve safety and bridge the gap between palliative medical therapy and definitive intervention. Full article

Primary open angle glaucoma (POAG) is one of the leading causes of irreversible blindness and is associated with dysfunction of the trabecular meshwork (TM), a three-dimensional (3D) structure that regulates aqueous humor outflow and, consequently, intraocular pressure (IOP). IOP is the only modifiable factor for glaucoma. Outflow facility is the inverse of aqueous humor outflow resistance caused by the presence of the TM and adjacent tissues, and reflects the TM’s central role in IOP control, representing the most physiologically relevant measure of human trabecular meshwork (HTM) function. Therefore, development of ex vivo systems to study outflow facility and IOP regulation is critical for advancing glaucoma research. We present a comprehensive review of bioengineering approaches to generation of 3D HTM models using synthetic, natural, and hybrid hydrogels, micro- and nanofabricated synthetic substrates or porous scaffolds, and microfluidic devices. These 3D HTM systems have been designed to capture key features such as topography, stiffness, and fluid flow in the conventional outflow pathway. In particular, we highlight HTM models that recapitulate IOP regulation and allow measurement of outflow facility, which directly reflect pressure-dependent outflow resistance in dynamic HTM physiology and glaucoma pathophysiology. By integrating these bioengineering approaches with emerging stem cell technologies, this review offers an evidence-based landscape overview and framework for designing next-generation 3D human-relevant TM models for outflow physiological studies and IOP-modulating drug discovery. Full article

Background: Secondary glaucoma in children results from congenital or acquired ocular abnormalities, systemic diseases, or syndromes. These conditions impair aqueous humor outflow despite an open iridocorneal angle, causing elevated intraocular pressure (IOP). Micropulse transscleral cyclophotocoagulation (MP-TSCPC) reduces aqueous humor production by targeting the ciliary body and restores the aqueous humor’s circulation balance. The aim of the study was to evaluate the safety and efficacy of MP-TSCPC in pediatric secondary glaucoma. Methods: This retrospective study included 59 children who underwent MP-TSCPC procedures. The mean age was 7.2 years (range 4 months–17 years). Data on IOP, prior glaucoma treatments, medication use, and adverse events were analyzed. The mean follow-up was 10.4 months. Results: The mean preoperative IOP was 34.0 mmHg, which significantly decreased to 25.8 mmHg after MP-TSCPC, representing a mean reduction of 20.8% (p < 0.0001). Satisfactory IOP lowering was achieved in 69.6% of procedures. Eyes without prior glaucoma surgery showed a numerically greater IOP reduction (22%) compared to previously treated eyes (19%), though the difference was not statistically significant (p = 0.628). Among repeated MP-TSCPC treatments, 57.1% were successful, with a mean IOP reduction of 7.3%. The mean number of glaucoma medications decreased significantly from 2.42 to 2.02 (p = 0.0002). A sustained reduction in medication use was observed in 33.3% of cases. Conclusions: MP-TSCPC effectively lowers IOP in pediatric secondary glaucoma and has a favorable safety profile. The option for repeated treatments and reduced medication needs supports its use as a less invasive alternative to conventional surgery. Full article

Global climate change and spatiotemporal heterogeneity in water resources exacerbate supply-demand imbalances. Accurate outflow simulation for joint reservoir group operations thus becomes critical for scientific water resources management. Existing data-driven models like the Long Short-Term Memory (LSTM) lack the robust integration of physical constraints. Traditional mechanistic methods, by contrast, lack generality and stability under complex hydrological conditions. To address this limitation, we propose MDUPLEX-KG-LSTM—a physically constrained data-driven model for reservoir outflow simulation. The model incorporates multi-round DUPLEX (MDUPLEX) data partitioning, which ensures statistical homogeneity across training, validation, and test datasets. It also features a Knowledge-Guided (KG) loss function that embeds core physical constraints: water balance, dead water level, flood season restricted water level, and inter-reservoir re-regulation mechanisms. Additionally, it adopts an LSTM network optimized via Particle Swarm Optimization (PSO) for enhanced predictive performance. We validate the model using daily hydrological data from 2010 to 2025 for three reservoirs in the Wujiaqu Irrigation District of Xinjiang, China. The model exhibits exceptional stability and predictive accuracy across key evaluation metrics: Nash–Sutcliffe Efficiency (NSE) ≥ 0.82, Pearson correlation coefficient (r) > 0.94, Root Mean Square Error (RMSE) ≤ 1.50 m³/s, and Water Balance Index (WBI) ≤ 0.016. It outperforms conventional data-driven and mechanistic models in extreme flow simulation scenarios. It also eliminates unphysical negative outflow values in all predictive results. The model achieves 100% compliance with flood control standards and an irrigation guarantee rate of no less than 86%. This study advances the development of physically constrained data-driven modeling for water resources engineering. It provides reliable methodological support for the intelligent operation of reservoir groups in smart water conservancy systems. The model also balances training cost and inference efficiency effectively. It demonstrates verified scalability for reservoir groups of varying scales, fully meeting the operational deployment requirements of smart water systems. Full article

Background: Catheter ablation is a validated treatment for ventricular arrhythmias (VA), but conventional radiofrequency (RF) energy may cause collateral injury due to non-selective thermal damage. Pulsed Field Ablation (PFA), a non-thermal modality based on irreversible electroporation, offers myocardial tissue selectivity and enhanced safety. While PFA is widely adopted for atrial arrhythmias’ ablation, its application in the ventricles remains an evolving frontier. Methods: We report a single-center experience using the Centauri PFA system integrated with a focal, contact-force sensing irrigated catheter (Tacticath™ SE, Abbott Laboratories, St. Paul, MN, USA) in four consecutive patients with drug-refractory VA. Two patients presented with frequent premature ventricular complexes (PVC) arising from the right and left ventricular outflow tract, respectively, while two had ischemic cardiomyopathy with recurrent scar-related ventricular tachycardia (VT). All procedures were guided by high-density mapping using the EnSite X system (Abbott Laboratories, St. Paul, MN, USA). Procedural safety, acute efficacy, and early follow-up outcomes were assessed. Results: All ablations achieved acute procedural success without complications. In both PVC cases, PFA led to immediate and complete suppression of ectopy, with a ≥95% reduction in arrhythmic burden at 12- and 9-months follow-up, respectively. In the VT cases, the arrhythmogenic substrate was effectively modified, rendering the clinical VT non-inducible. ICD interrogation during a 9-month follow-up showed complete absence of recurrent sustained VT. No coronary spasm, atrioventricular block, pericardial effusion, or other adverse events occurred. Conclusions: In this initial experience, focal PFA using a contact-force sensing catheter appeared feasible and effective for both focal and scar-related VA. This system provides an intuitive workflow similar to RF ablation. While our data suggest a favourable safety profile, larger studies are required to definitively confirm safety margins near critical structures. Full article

Accurately forecasting traffic congestion on urban expressways remains challenging, especially under unstable flow conditions where conventional machine learning models often suffer from reduced accuracy and interpretability. This study introduces a domain-theoretic machine learning framework designed for real-time congestion prediction on the Chalong Rat Expressway in Bangkok, Thailand. Feature engineering incorporates principles from the macroscopic cell transmission model, Kerner’s three-phase theory, and Helbing’s microscopic dynamics to capture key interactions such as density–flow relationships, jam propagation, and driver response gradients. A hybrid random forest–XGBoost ensemble is developed and evaluated against standard machine learning baselines. The results demonstrate that the proposed ensemble achieved superior performance across mean absolute error (MAE), root mean square error (RMSE), coefficient of determination (R²), and prediction interval coverage (PICP), particularly near congestion transition boundaries. SHapley Additive exPlanations (SHAP) analysis confirmed corrected outflow, jam speed, and repulsive force as dominant predictors, underscoring the model’s interpretability. By integrating traffic theory with interpretable machine learning, this framework enables accurate, explainable, and deployable real-time congestion forecasting for intelligent transportation systems. Full article

The optimization of pump setting depth in low-permeability oil wells remains a persistent challenge, as conventional inflow performance relationship (IPR) curves fail to capture the coupled effects of downhole pump intake depth and reservoir productivity. To address this limitation, this study proposes a novel Low-Permeability Intake Inflow Performance Relationship (LIIPR) framework. The method establishes a theoretical link between pump depth and production by integrating low-permeability reservoir inflow models with multiphase wellbore flow calculations. On this basis, a series of derivative concepts and analytical tools are introduced, including (i) a three-zone classification of inflow curves to distinguish effective, inefficient, and abnormal production regimes; (ii) a multi-pump-depth analysis to determine the feasible range and optimal boundaries of pump setting depth; and (iii) a three-dimensional deep-pumping limit map that couples inflow and outflow dynamics through nodal analysis, providing a comprehensive criterion for system optimization. The proposed LIIPR methodology enables accurate identification of optimal pump depth and intake pressure conditions, overcoming the ambiguity of traditional IPR-based approaches. Unlike previous IPR- or EIPR-based methods, LIIPR introduces for the first time a unified inflow–outflow coupling framework that quantitatively links pump intake depth with well productivity. This integration represents a novel theoretical and computational advance for deep-pumping optimization in low-permeability reservoirs. Applications for field cases in Shengli Oilfield confirm the theoretical findings and demonstrate the practical potential of the method for guiding efficient deep pumping operations in low-permeability reservoirs. Full article

To mitigate persistent urban–rural disparities and facilitate comprehensive rural development, the Chinese government institutionalized the Rural Revitalization Strategy. This national policy framework systematically addresses five critical domains of rural development: (1) industrial revitalization, (2) talent revitalization, (3) organizational capacity building, (4) cultural heritage preservation, and (5) ecological conservation. Among them, talent cultivation serves as both a fundamental objective and critical resource for the sustainable rural economic transformation. However, the existing research and practice have disproportionately emphasized industrial and ecological aspects, largely neglecting the acute talent shortage. This study bridges this gap by adopting a population mobility lens to categorize young talent types contributing to Chinese rural economic transformation and analyze their mobility trajectories and resource exchange dynamics. Drawing on an integrated theoretical framework combining Push–Pull Theory and Existence–Relatedness–Growth Theory, as well as empirical evidences from Yuan Village in Shaanxi Province, this research has four key findings. First, there are three distinct young talent categories that have emerged in Chinese rural economic transformation: urban-to-rural young talents, native young talents, and rural-to-rural young talents. It is noteworthy that the rural-to-rural young talent represents a novel flow pattern that can expand our conventional understandings of Chinese population mobility. Second, differential push–pull factors shape each category’s migration decisions, subsequently influenced by their existence needs, social relatedness, and growth requirements as outlined in ERG Theory. Third, through heterogeneous resource exchanges with villagers, committees, and communities, these talents negotiate their positions and satisfy their expectations within the rural socio-economic system. Fourth, unmet exchange expectations may precipitate talent outflow, which will further pose sustainability challenges to revitalization efforts. Additionally, the long-term impacts of the intensified social interactions between talent groups and local residents, as well as their generalizability, require further examination. Full article