Search Results (2,542)

Background: Continuous-flow left ventricular assist devices (LVADs) generate non-pulsatile circulation, rendering conventional oscillometric blood pressure measurements unreliable. Accurate monitoring is critical to prevent complications including stroke, pump thrombosis, and aortic regurgitation. Doppler-based measurement is widely used as a non-invasive alternative, yet its accuracy relative to invasive arterial pressure remains insufficiently characterized. Methods: In this prospective single-centre study, 32 adult continuous-flow LVAD patients underwent simultaneous invasive radial artery and Doppler blood pressure measurements twice daily over three consecutive days (192 paired readings; Day 3: n = 27 due to technical recording issues). Pulsatility was assessed by means of peripheral pulse palpation and transthoracic echocardiography. Spearman’s rho, Wilcoxon signed-rank test, and Bland–Altman analysis were applied. Results: Median invasive MAP was 73.0 [IQR 66–80] mmHg and median Doppler pressure was 75.0 [IQR 70–80] mmHg. Doppler measurements demonstrated strong-to-excellent correlation with invasive MAP across all time points (r = 0.78–0.91, p < 0.001), with no significant paired differences (all p > 0.05). Bland–Altman analysis revealed a bias of −0.35 mmHg with limits of agreement of −9.10 to +8.40 mmHg, within the accepted ±10 mmHg threshold. Correlation with systolic pressure was lower (r = 0.66–0.89, p < 0.001), with a positive bias of +13.47 mmHg and wide limits of agreement (+1.28 to +25.67 mmHg), indicating clinically unacceptable agreement. Conclusions: Doppler-derived blood pressure may provide a reliable estimate of invasive MAP in continuous-flow LVAD patients, whereas its utility for systolic pressure estimation appears limited. Doppler measurement represents a practical, non-invasive tool for routine MAP monitoring in both inpatient and outpatient settings. Full article

Increasing pressure on surface water resources in intensive agricultural regions has driven the search for sustainable alternatives for irrigation supply, especially in areas where water quality limits crop safety and export opportunities. In this context, riverbank filtration (RBF) systems offer a nature-based solution by utilizing physical, chemical, and biological processes associated with river–aquifer exchange. However, their implementation depends on suitable site selection supported by hydrogeological, geomorphological, and hydraulic criteria. This study developed an integrated methodology to identify zones with potential for implementing RBF systems in the Roldanillo–Unión–Toro irrigation district, located in northern Valle del Cauca, Colombia. This region requires irrigation water over 10,256 ha of agricultural land (mainly sugarcane, maize, grapes, and guava). We combined geophysical methods (vertical electrical soundings, 2D electrical resistivity tomography, and passive seismic), geotechnical methods (CPTu tests), and hydraulic characterization of the river reach to evaluate subsurface stratigraphy, preliminary hydrogeological suitability, inferred river–aquifer connectivity conditions, and channel stability. The evaluation covered four sectors along an approximately 21 km stretch of the Cauca River’s left-bank alluvial valley. The results revealed pronounced lateral and vertical heterogeneity of alluvial materials. However, the “El Palmar” sector was identified as the best-supported priority sector for future RBF validation, due to the presence of profile-scale evidence of potentially permeable sandy and gravelly units with intermediate resistivity values (52–61 Ω·m), favorable stratigraphic organization, and stable river-reach conditions during the field campaign. In contrast, the other three sectors (La Esperanza, Candelaria, and Cayetana) showed more fine-grained sediments with deeper permeable strata. River-flow measurements during the July 2025 field campaign indicated high discharge conditions at the evaluated reach, while river-channel observations showed active fine-sediment transport; these findings provide hydraulic and sedimentary context for the future evaluation of induced infiltration and potential clogging, but do not constitute direct evidence of river–aquifer exchange. This study highlights the value of integrated screening approaches for prioritizing candidate RBF sites in agricultural alluvial settings, while indicating that pumping tests, piezometric monitoring, hydraulic-gradient analysis, and water-quality validation remain necessary before engineering implementation. Full article

Accurate fault classification of electro-hydrostatic actuators (EHAs) remains challenging because multivariate fault signals contain local transient variations, inter-variable coupling, and dynamic temporal dependencies that are difficult to capture simultaneously using a single model. To address this problem, this paper proposes a multi-view temporal feature collaborative heterogeneous ensemble learning model (MTF-HEM) for EHA multivariate time series fault classification. MTF-HEM integrates a representative subsequence-guided time series forest (RSG-TSF), XGBoost, and a lightweight LSTM to extract local morphological, global statistical, and temporal dependency features, respectively. The outputs of these heterogeneous base learners are fused using a bootstrap-driven out-of-bag probability binning stacking (BOPB-stacking) strategy. The proposed method was evaluated on an AMESim-based simulated EHA plunger pump fault dataset containing one normal condition and six fault conditions. Under the present simulation setting, MTF-HEM achieved an accuracy of 99.52% and outperformed the tested deep time series classification models, ensemble models, and individual base learners. These results suggest that multi-view heterogeneous feature fusion can improve the classification of simulated EHA fault time series and provide a methodological reference for intelligent actuator fault diagnosis. However, the current validation is based on data generated from a single AMESim simulation model, and further evaluation on real EHA systems is needed to assess the practical applicability and generalizability of the proposed approach. Full article

Background/Objectives: Neisseria gonorrhoeae is a high-priority pathogen for the development of new therapeutic alternatives. Efflux pumps are attractive drug targets because their inactivation influences N. gonorrhoeae susceptibility to multiple antimicrobials. Since most gonococcal efflux systems are energy-dependent, interference with energy metabolism and membrane transport may indirectly compromise efflux activity. Efflux inhibitors may increase intracellular antibiotic concentration, although this requires validation in resistant strains. The most effective efflux inhibitors interfere with energy metabolism, affecting several physiological processes, including efflux. In this work, we used an in silico drug repurposing strategy targeting proteins involved in membrane transport and energy metabolism in N. gonorrhoeae. A subset of candidate drugs were subsequently evaluated in vitro using only the reference strain N. gonorrhoeae ATCC 49226. Methods: Predicted drug–target interactions were identified using publicly available databases such as DrugBank and STITCH. Minimum inhibitory concentrations (MICs) of selected drugs against N. gonorrhoeae were determined by microdilution. Changes in intracellular ethidium bromide accumulation were assessed by real-time fluorometry as an indirect indicator of possible efflux-related interference. Results: In silico analysis identified 32 predicted targets associated with 57 approved drugs. Triclabendazole and dequalinium showed the lowest MIC values of the tested compounds (2 and 4 mg/L, respectively). Ketotifen and verapamil demonstrated activity consistent with possible efflux interference, as indicated by increased ethidium bromide accumulation. Atovaquone showed adjuvant-like effects in combination assays, suggesting that mechanisms other than efflux-related interference may contribute to its activity. Conclusions: Overall, this preliminary study identifies approved drugs with antimicrobial or adjuvant activity against a single N. gonorrhoeae reference strain, supporting further investigation in clinically relevant and efflux-variant strains. Full article

To address the bottlenecks of conventional valve-controlled marine steering systems—characterized by high throttling losses, low efficiency, and high leakage risk—as well as the insufficient power density and impact resistance of electro-mechanical actuators (EMAs) for high-load steering of large vessels, this paper proposes and validates a high-performance integrated solution for an electro-hydrostatic actuator (EHA) for ship steering. First, a fifth-order electro–hydraulic–mechanical coupled dynamic model comprising a permanent magnet synchronous motor, hydraulic pump, hydraulic cylinder, and load is established. The validity and applicability boundaries of three simplifying assumptions—neglecting leakage, pipeline pressure losses, and steady-state fluid compressibility effects—are quantitatively analysed, with a total introduced error ≤3%. These assumptions are justified under medium-pressure, short-pipeline, and well-sealed conditions typical of marine EHA systems. Second, a composite control architecture combining outer-loop sliding mode control with inner-loop motor PID dual-loop control is proposed. Parameter tuning is performed using pole placement for the sliding surface and the Ziegler–Nichols critical ratio method for the inner loops, effectively suppressing hydraulic system parameter perturbations and random wave-induced load disturbances. Quantitative comparisons show that the proposed method reduces overshoot by 11.63% and improves sinusoidal tracking accuracy by 90.13% compared to conventional single-loop PID control. An integrated drive-control structure is designed, and a three-phase full-bridge inverter main circuit with wide-voltage input capability—including EMI filtering, soft-start, and LC filtering—is developed to accommodate the ±20% voltage fluctuations typical of ship power grids, thereby enhancing system integration and grid adaptability. Phased bench tests demonstrate that the settling time from no-load start-up to 200 r/min is only 0.01 s. When a sudden 20 N·m load is applied, the speed drop is less than 3%, and the recovery time is less than 0.025 s. The steady-state steering angle error does not exceed 0.12°, the maximum average steering rate reaches 3.33°/s, and the steering response time is within 0.3 s. All core performance indicators exceed the general technical standards for marine steering systems, with a 65.7% improvement in steady-state accuracy and a 62.5% improvement in response speed over conventional PID control. The research findings provide an effective general technical solution and experimental data support for the performance optimization and engineering application of marine EHA systems. Full article

Introduction: The declining efficacy of standard triple therapy for Helicobacter pylori (H. pylori) eradication, largely driven by increasing antibiotic resistance, has highlighted the need for alternative treatment strategies. Vonoprazan–amoxicillin dual therapy (VDT) has emerged as a promising regimen due to the potent and sustained acid suppression provided by vonoprazan. This meta-analysis aims to compare the efficacy and safety of VDT versus clarithromycin-based standard triple therapy (STT) for H. pylori eradication in adults. Methods: A systematic search of PubMed, Scopus, and the Cochrane Library was conducted from inception to 15 March 2026 for randomized controlled trials (RCTs) comparing VDT (vonoprazan plus amoxicillin) with STT (proton pump inhibitor, amoxicillin, and clarithromycin) for H. pylori eradication (PROSPERO “CRD420261357715”). Heterogeneity was assessed using the I² statistic and Cochran’s Q test. Risk ratios (RRs) with 95% confidence intervals (CIs) were calculated using the Mantel–Haenszel method within a restricted maximum-likelihood random-effects model. Results: Five RCTs were included with 1363 patients (VDT: 680, STT: 683). VDT demonstrated a significantly higher H. pylori eradication rate compared with STT (RR 1.17; 95% CI [1.07; 1.27]; p = 0.007; I² = 11%). Conclusions: This meta-analysis suggests that VDT may be associated with higher H. pylori eradication rates than clarithromycin-based STT. Further large, well-designed RCTs are needed before firm first-line recommendations can be made. Full article

Nanocolloid research has undergone a complete transformation, renouncing the empirical estimation of properties and relying on real case scenarios. The main objective of this paper is to compare a large number of samples that were experimentally studied in terms of thermophysical properties in order to be able to draw a conclusion in terms of the heat transfer efficiency of a certain surfactant addition to a 2 wt.% TiO₂ nanoparticle-enhanced fluid. The analysis discusses both the advantages and drawbacks in terms of surfactant type and concentration influence over the Prandtl number, thermal diffusivity, and Nusselt number, as well as the heat transfer coefficient for different Reynolds numbers in laminar flow. The investigation also includes a different figure of merits and performance evaluation criteria that are extensively employed in the literature in order to have a complete overview of the efficiency of surfactants in improving nanocolloids. In conclusion, even if surfactants are considered for improving nanocolloid stability, their drawbacks have not been debated in depth in the open literature. The main conclusion that arises from this study outlines that among all tested samples, F127 at a concentration of 0.25 wt.% consistently demonstrates the best overall performance, achieving an optimal balance between enhanced thermal properties and acceptable pumping requirements. 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

The development of age-appropriate pediatric dosage forms remains an important challenge, particularly for acid-labile drugs requiring gastro-resistant protection. Pantoprazole, a proton pump inhibitor, must be protected from gastric acid until intestinal absorption; however, conventional enteric-coated tablets may be difficult to use in younger children, while manipulation of dosage forms or mixing with food can compromise dose accuracy and drug release performance. Multiparticulate systems, such as minitablets, pellets, or granules, offer flexible dosing but may still require a suitable vehicle to improve acceptability, handling, and ease of swallowing. In this study, enteric-coated pantoprazole minitablets were developed and evaluated after dispersion in selected hydrogel vehicles intended to serve as standardized alternatives to food-based carriers. Hydrogels based on hypromellose (HPMC), carbomer (CAR), and sodium alginate (SA) were characterized in terms of pH, rheological properties, firmness, acid penetration, and their effect on pantoprazole release. Dissolution performance was assessed using both conventional pharmacopoeial testing and dynamic non-pharmacopoeial conditions. Low-concentration gels prepared from high-viscosity HPMC grades showed the most favorable performance, combining suitable spoonable consistency with limited impact on drug release. Among them, 5% HPMC 65SH4000 was particularly promising, as it did not markedly delay pantoprazole release in either pharmacopoeial or dynamic dissolution testing. CAR gels provided advantageous rheological properties, including high viscosity at rest and shear-thinning behavior, and allowed efficient pantoprazole release after transition to buffer conditions; however, their interaction with enteric-coated minitablets should be further optimized with respect to gel amount, concentration, and neutralization strategy. SA gel showed strong structural persistence and delayed release under pharmacopoeial conditions, although this effect was less pronounced in the dynamic model. Overall, the findings indicate that appropriately selected hydrogels may improve the practical use of pediatric multiparticulate formulations, but their composition, pH, rheology, and interaction with enteric coatings must be carefully evaluated. Full article

Small intestinal bacterial overgrowth (SIBO) refers to an abnormal increase in the number of bacteria in the small intestine and is observed in various diseases. SIBO can also develop after long-term use of proton pump inhibitors (drug-induced SIBO), bariatric surgery, gastrectomy, and other surgeries (postoperative SIBO). The aim of this narrative review is to summarize all of the published information on the treatment of SIBO in as much detail as possible and present it separately for each specific disease and intervention associated with SIBO. The most extensively studied drug for the treatment of SIBO is rifaximin. It eliminates SIBO in 63% of cases; however, most studies lack a control group. Small RCTs assessing the effects of this antibiotic on SIBO have reported conflicting results, and a meta-analysis showed no effect. A large RCT is required to verify the results of uncontrolled studies. Neomycin and norfloxacin showed efficacy in the treatment of SIBO in single RCTs, with elimination rates of 20 and 100%, respectively. Ciprofloxacin, rifamycin, metronidazole, and other antibiotics, as well as ursodeoxycholic acid, showed positive effects for the treatment of SIBO, but only in uncontrolled studies or in comparison with rifaximin or other drugs. The reported elimination rates were 54%, 67%, 79%, and 75%, respectively. Eradication therapy for Helicobacter pylori infection eliminated SIBO at a rate of approximately 70%. Probiotics have been tested for treatment of SIBO in various diseases. VSL#3 and Saccharomyces boulardii CNCM I-745 were effective in RCTs, with elimination rates of 58% and 80%, respectively. In conclusion, when selecting SIBO treatment regimens, those that have demonstrated the greatest efficacy for a specific concomitant disease should be preferred, despite the generally low level of evidence supporting these approaches in most cases. Full article

In industrial applications such as in situ leaching and uranium mining, permanent magnet synchronous motors (PMSMs) for submersible pumps are frequently connected to frequency converters via long cables. During this long-distance transmission, traveling wave reflections induced by high-frequency pulse width modulation (PWM) generate severe transient overvoltages that threaten motor insulation. Because installation space at deep-well motor terminals is severely restricted, overvoltage suppression must be implemented at the inverter output. Here, the parameter design and optimization of a passive LC filter specifically developed for 250 Hz high-frequency PMSMs are presented. The optimal inductance and capacitance parameters were determined by balancing multiple operational constraints, including fundamental voltage drop, high-frequency harmonic attenuation, and the avoidance of low-order harmonic resonance. Furthermore, the anti-saturation performance of the magnetic core material, evaluated thermal characteristics through electromagnetic-thermal co-simulation, and analyzed the risk of self-excited oscillation between the filter capacitors and the motor was analyzed. Finally, hardware experiments conducted on a 20 m cable test bench validate that the designed LC filter effectively mitigates terminal overvoltage. The peak terminal voltage was reduced from 900 V to 505 V, and total harmonic distortion (THD) was limited to below 5%. This design provides a highly reliable, space-efficient solution for overvoltage suppression in high-speed, long-cable motor drive systems. Full article

This study presents a novel investigation into the coupled effects of ambient temperature and compressor frequency on frosting behavior and thermal performance of inverter-driven air-source heat pumps (ASHPs) under low-temperature, high-humidity conditions. Unlike previous studies that focused on single environmental parameters, this work systematically explores temperature–frequency coupling. Experiments were conducted on a 3-HP DC inverter low-ambient-temperature ASHP unit using a multi-climate simulated enthalpy difference test bench. Single-factor analysis shows that frosting is most severe at 0 °C, where the frost growth rate peaks. Regarding compressor frequency, the coefficient of performance (COP) initially increases and then decreases with frequency. The maximum COP occurs near 45 Hz, representing the optimal energy efficiency balance in this experimental system. Sensitivity analysis demonstrates that relative humidity contributes less than 5% to performance degradation at the critical 10% COP reduction point. Thus, ambient temperature and compressor frequency are the core determinants of defrosting timing. A dual-factor prediction model for the critical defrosting air-to-coil temperature difference (∆T) is developed using temperature (t) and frequency (f) as independent variables. Validation confirms that the model maintains prediction error within 10% under both single-factor and multi-factor coupling conditions. Collectively, this research quantifies the coupled effects of ambient temperature and compressor frequency on frosting performance and provides a novel theoretical framework for precise defrosting control in inverter ASHPs based on performance attenuation. Full article

Bacopa monnieri (BM) is a traditional medicinal herb that has been reported to have neuroprotective and cognitive-enhancing properties. In this study, the antioxidant, safety, and neuroprotective properties of BM extract (BME) were assessed in a lipopolysaccharide (LPS) model of cognitive impairment. Ethanol was used for extraction, after which the ethanolic extract was profiled to characterize total phenolic and flavonoid content and major bioactive constituents. The assessment of antioxidant activity was done through several in vitro tests (DPPH, ABTS, FRAP, NBT, OARC, and metal chelation). Toxicity was assessed in Caenorhabditis elegans using pharyngeal pumping and food clearance tests. For in vivo evaluation, rats were pre-treated with BME, and then LPS was administered, followed by evaluation of cognitive performance by the Morris water maze and Y-maze test. Phytochemical examination revealed the existence of phenolics and flavonoids, as well as bacoside A components. The extract showed good antioxidant activity, mainly via hydrogen atom transfer and single-electron transfer, suggesting effective radical scavenging and reducing ability, but no metal chelating activity was observed. Toxicity tests demonstrated that lower concentrations of the extract were well tolerated, and higher concentrations resulted in temporary inhibition of feeding behavior, indicating mild, dose-dependent effects. In the LPS-induced rat model, the inflammatory challenge produced significant cognitive deficits relative to normal controls, validating the model. Pre-treatment with BME at 70 mg/kg did not produce statistically significant rescue of any behavioral endpoint compared with the LPS-only group, although small-to-medium effect sizes in the protective direction were observed for several measures. Additionally, BME modulated LPS-induced neuroinflammatory responses by reducing cortical IL-1β, TNF-α, iNOS, and COX-2 levels while enhancing hippocampal AChE and PGE2 activity, suggesting region-specific anti-inflammatory and cholinergic regulatory effects. The most robust positive findings of this study are therefore the phytochemical characterization and the in vitro antioxidant profile of this standardized extract, which support its potential as a candidate for further investigation in inflammation-related cognitive impairment; the in vivo findings are preliminary and warrant confirmation in larger-scale, dose-ranging studies. Full article

High-speed permanent magnet synchronous motors (PMSMs) used in electric pump-fed liquid rocket engines require stator shielding sleeves to prevent corrosive propellants from causing harm under cyclic pressure. However, metallic sleeves suffer significant losses due to eddy currents. Conversely, pure carbon fiber reinforced polymer (CFRP) sleeves have failed when exposed to 98% H₂O₂. Micro-CT analysis of a failed pump sleeve reveals a four-stage failure mechanism. Manufacturing defects caused matrix cracking, which propagated under pressure and thermal cycling. This progression resulted in the formation of through-thickness leakage paths, which ultimately triggered catalytic decomposition and explosion. To address these issues, an improved dual-layer sleeve is proposed, featuring a 2.5 mm PEEK 450G liner and a 2.0 mm T700S/epoxy CFRP overwrap. Finite Element Analysis (FEA) indicates peak von-Mises stresses of 86.25 MPa and 112.16 MPa, yielding Tsai–Wu safety factors of 2.9 and 1.7. Furthermore, various tests, including immersion, fatigue, burst, hydraulic, and thermal evaluations, demonstrate a burst margin of 2.37× at 7.12 MPa, with only 0.19% increase in mass. This design effectively eliminates leakage pathways while preserving zero eddy-current loss and ensuring a low weight. Full article

Geothermal energy, a clean and reliable renewable resource, is attracting growing global attention. Predicting geothermal productivity is essential for the sustainable management of geothermal systems in conventional pumping tests, but the water level has a highly nonlinear correlation with reservoir physical conditions, and traditional numerical simulation methods fail to capture their intrinsic relationship. This study proposes a novel hybrid deep learning model of Graph Convolutional Networks (GCN) and Transformers for geothermal pumping tests, which efficiently predicts water level under nonlinear physical constraints: GCN learns the nonlinear mapping between water level depth and physical constraints, while Transformer preserves the temporal sequence correlations of production data via self-attention mechanism. Validation with test data showed that the model achieved an R² of 0.97 and an RMSE of 0.1635 m for production wells, and an R² of 0.94 and an RMSE of 3.9057 m for reinjection wells under different geological conditions. Its R² showed improvements of 13.82%, 7.83%, and 5.95% compared with the LSTM, Transformer, and GCN–LSTM models, respectively. This study provides an accurate and efficient technical approach for geothermal productivity prediction, supporting the optimization of pumping test schemes and production capacity evaluation in preliminary geothermal resource development. Full article