Search Results (1,402)

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

This study investigates graphene oxide/carboxymethyl cellulose composite membranes containing 3 wt.% graphene oxide. The influence of the carboxymethyl cellulose content on the structural organization, mechanical properties, electrical resistivity, and humidity-dependent conductivity was systematically analyzed using Fourier transform infrared spectroscopy, scanning electron microscopy, X-ray diffraction, tensile testing, and electrical measurements. Fourier transform infrared spectroscopy indicated intermolecular interactions between graphene oxide and carboxymethyl cellulose functional groups. X-ray diffraction analysis showed gradual inter-layer expansion from 0.71 to 0.87 nm together with crystallite size reduction after polymer incorporation. Scanning electron microscopy observations demonstrated the increasing structural uniformity and polymer encapsulation of graphene oxide sheets with the increasing carboxymethyl cellulose content. Mechanical testing revealed improvement in the tensile strength from 6.6 to 17.8 MPa with the increasing carboxymethyl cellulose concentration. Simultaneously, the dry-state electrical resistivity increased from 5.8 × 10⁶ to 2.32 × 10⁷ Ω·m due to increasing dielectric separation between graphene oxide domains. Humidity-sensing experiments demonstrated reversible resistance changes in the 20–90% relative humidity range, associated with proton-assisted conduction through adsorbed water layers. The obtained results demonstrate that polymer incorporation strongly influences both the structural organization and electrophysical behavior of graphene oxide/carboxymethyl cellulose composite membranes. Full article

In view of the fact that there are few reports on the preparation of NbC coating by high-power pulsed magnetron sputtering (HiPIMS) technology. In this study, the effects of NbC interlayer thickness on the microstructure, corrosion resistance and electrical conductivity of Nb/NbC/C multilayer coatings for proton exchange membrane fuel cell (PEMFC) bipolar plates were studied by using the high ionization characteristics of HiPIMS technology. A series of Nb/NbC/C multilayer coatings with varying NbC interlayer thicknesses was deposited via HiPIMS by modulating the deposition time (20, 40, and 60 min). The microstructure and properties of the coatings were characterized using scanning electron microscopy (SEM), Raman spectroscopy, interfacial contact resistance (ICR), and corrosion current, among other methods. The results indicate that as the NbC interlayer thickness increases, the total coating thickness increases from 0.43 μm to 1.42 μm. All coatings exhibit a uniform and dense microstructure lacking typical coarse columnar structures. Raman and XPS analyses show that the I_D/I_G ratio increases from 1.98 to 4.04, indicating an increase in sp²-hybridized bond content and a decrease in sp³ content. At a deposition time of 60 min, the coating achieved optimal performance, yielding a critical load (Lc1) of 31.9 N, the lowest average friction coefficient (0.27), the minimum corrosion current density, and an interfacial contact resistance of 7.5 mΩ·cm². These results demonstrate that the NbC interlayer thickness significantly governs the structure and properties of the Nb/NbC/C multilayer coatings. Specifically, an appropriate increase in the NbC interlayer thickness optimizes the sp²/sp³ hybrid bond ratio, thereby enhancing the overall coating performance. Full article

Proton exchange membrane fuel cell–battery hybrid power systems provide an effective solution to overcome the limited endurance of battery-powered multirotor unmanned aerial vehicles. However, the highly transient power demands of quadcopter platforms, combined with balance-of-plant losses and operational constraints, create significant challenges for reliable energy management. This study proposes a degradation-aware stress-mitigation model predictive control-based energy management framework to maximize mission endurance under realistic conditions. A control-oriented, physics-consistent model is developed using manufacturer polarization data from a 500 W Aerostak proton exchange membrane fuel cell. The model captures polarization behavior, balance-of-plant loads, battery dynamics, and direct current-bus power balance. The model predictive control strategy optimally allocates power by maintaining direct current-bus stability, regulating battery state-of-charge within safe limits, and constraining fuel cell power ramp rates to mitigate degradation. High-fidelity simulations are conducted under stochastic wind disturbances and mission-dependent load profiles, including takeoff, climb, cruise, and maneuvering phases. The results show continuous power delivery without unmet load demand. The hybrid system achieves a flight endurance of 220–224 min, consuming a total of 89.99 g of hydrogen at an average rate of 0.398–0.412 g/min, indicating a notable reduction under the considered operating conditions. Additionally, long-term analysis indicates that over 97% of initial endurance is preserved after 100 cycles, demonstrating robustness against fuel cell aging. An analytical real-time feasibility assessment further indicates that the control-oriented formulation is compatible with the computational resources of typical unmanned aerial vehicle-class onboard processors, while the integration of adaptive and robust predictive control techniques is identified as a direction for future work. Full article

Open-cathode Proton Exchange Membrane Fuel Cells (PEMFCs) are a promising technology for increasing the endurance of small Unmanned Aerial Vehicles (UAVs), ground robots, e-bikes, and light electric vehicles. However, their performance under realistic operating conditions is strongly influenced by rapid variations in load, temperature, and ambient pressure, which are often neglected in design-oriented or quasi-steady-state analyses. This study experimentally investigates a 1 kW open-cathode PEMFC system, including its balance of plant and a passive supercapacitor buffer, under a representative UAV flight power profile. Steady-state and dynamic tests were conducted to assess polarization characteristics, thermal behavior, parasitic power consumption, and hydrogen utilization. Results revealed significant thermal inertia and hysteresis effects during load transients, causing voltage deviations from steady-state performance and stabilization times exceeding 90 s. The supercapacitor effectively reduced stack current ramp rates, although some high-frequency oscillations remained. Under flight-representative conditions, the system achieved stable operation with average voltaic efficiency ranging from 55.3% to 60.7% and net efficiency ranging from 50.2% to 54.2%. Auxiliary components had a measurable impact on overall performance: cooling fans accounted for 2–6% of stack power during steady operation and approximately 2.5% of total mission energy, while hydrogen purge losses can significantly reduce vehicle endurance. The findings demonstrate the importance of energy-based performance assessment, including auxiliary loads and purge losses, to obtain realistic estimates of efficiency and endurance in dynamic PEMFC-powered applications. Full article

Template removal represents a critical yet often underexplored step in the fabrication of electropolymerized molecularly imprinted polymers (e-MIPs), directly influencing cavity integrity, selectivity, and sensor performance. In this review, we provide a comprehensive analysis of the most commonly employed template removal strategies, including immersion-based methods and electrochemical cleaning, with a particular focus on systems based on polypyrrole (PPy) and poly(o-phenylenediamine) (PoPD). We examine how template removal conditions, such as solvent composition, pH, and applied potential, affect polymer structure, doping state, swelling behavior, and electrochemical properties. Special attention is given to mechanistic aspects such as protonation/deprotonation, overoxidation, and polymer–template interactions, which govern both remotion efficiency and potential degradation pathways. By comparing PPy and PoPD systems, we highlight how intrinsic polymer properties dictate the suitability of specific removal strategies. Additionally, we discuss emerging approaches, including multi-step template removal protocols and the incorporation of conductive nanomaterials to mitigate performance loss. This work aims to provide a mechanistic perspective on how template removal conditions affect polymer structure, electrochemical properties, and the overall performance of e-MIP-based sensors. Full article

Polymer electrolyte membranes serving in proton exchange membrane fuel cells (PEMFCs) and direct methanol fuel cells (DMFCs) must possess sufficient mechanical–dimensional stability and excellent proton conducting capacity. Derived from the successful syntheses of two different sulfonated poly(aryl ether ketone)s bearing functional amine groups, two series of novel epoxy-crosslinked and silane-crosslinked sulfonated poly(aryl ether ketone) electrolyte networks are constructed for highly conductive and mechanically stable proton exchange membranes. The designed multi-component architecture, which integrates a moderate-ion-exchange-capacity sulfonated poly(aryl ether ketone) (moderate-IEC SPAEK), a high-IEC SPAEK, and a tailored crosslinker (epoxy or silane), enables a breakthrough in decoupling the traditional trade-off between conductivity and stability. The resulting membranes exhibit an outstanding combination of properties: exceptional proton conductivity exceeding 0.18 S cm⁻¹ at 100 °C, tensile strength above 28.80 MPa, and enhanced chemical resistance, thermo-oxidative stability, and competitive direct methanol fuel cell performance. This work establishes a rational design strategy for crosslinked multi-component membranes as a promising platform for next-generation high-performance fuel cells. Full article

Expansion of the operational temperature range for polymer-electrolyte membrane fuel cells (PEMFCs) above 200 °C significantly reduces hydrogen purification requirements. Here, we report a hybrid composite of poly(2,5-benzimidazole) (ABPBI) and CsH₂PO₄, doped with H₃PO₄, as a PEM for PEMFC operation at >200 °C up to 250 °C and beyond. The optimal ratio of ABPBI repeating units to CsH₂PO₄ is 1:1 (mol/mol). Materials are extensively characterized by elemental analysis, scanning electron microscopy, HAADF STEM, elemental mapping, electrochemical impedance spectroscopy, proton conductivity, mechanical testing, and Fourier transform infrared spectroscopy. It is suggested that PEMFCs with the extended operational temperature range (>220 °C) might be categorized as ultrahigh-temperature polymer-electrolyte membrane fuel cells (UT-PEMFCs). Full article

Purpose: To develop an accelerator neutron source suitable for boron neutron capture therapy—a new promising method for treating malignant tumors—and to develop dosimetry tools and methods. Methods: Research into the transport and acceleration of a beam of charged particles, development and manufacture of an accelerator neutron source, study of the radiation generated, and development and implementation of dosimetry tools and methods. Results: A facility called VITA has been created, which includes a tandem electrostatic accelerator of an original design for producing a 2.3 MeV 10 mA proton beam, a lithium target for generating neutrons in the ⁷Li(p,n)⁷Be reaction, and a beam shaping assembly for forming a therapeutic neutron beam. The facility at the institute is used for scientific research, the facility in Xiamen (China) is used for clinical trials, and the facility in Moscow (Russia) will soon be used for clinical trials. Also, new tools and methods for measuring the boron dose, γ-ray dose, and sum of the fast neutron dose and the nitrogen dose have been proposed and implemented. The conducted studies demonstrated the high efficiency of the VITA^® facility, the first possibility of implementing prompt γ-ray spectroscopy for boron imaging, and the first possibility of implementing lithium neutron capture therapy, which has advantages over BNCT, and also presented the results of the development of new tools and methods for measuring the boron dose, γ-ray dose, and the sum of the fast neutron dose and the nitrogen dose. Conclusions: The authors strongly recommend using prompt γ-ray spectroscopy in treatment and developing lithium neutron capture therapy, including in combination with BNCT, and note the high efficiency, reliability and compactness of the VITA^® facility. Full article

The electrochemical performance of hydrogen compressors (EHCs) depends critically on the hierarchical microstructure of their catalyst layers (CLs), where platinum, carbon, and ionomer phases govern coupled charge and mass transport across nanometric (Nano) and mesoporous (Meso) scales, the latter characterized by agglomerate and pore phases. This work presents an experimental–computational framework to establish quantitative microstructure–transport–performance relationships in EHC CLs. CLs were fabricated by electrospray deposition on Nafion^® 117 membranes and characterized by scanning electron microscopy, from which 33 representative Meso MCs were extracted and used to assemble an EHC cell for experimental polarization curves. Statistically equivalent Nano MCs resolved phase connectivity within the agglomerate phase and determined the effective catalyst area from neighboring phase configurations. Effective transport coefficients for electronic conductivity, protonic conductivity, and H₂ diffusivity were computed via the finite volume method and multiscale-coupled into an analytical polarization model. Electronic and protonic conductivities are controlled by conductive-phase connectivity at the Nano scale, while H₂ diffusivity is governed by the pore fraction and spatial distribution at the Meso scale, with variations exceeding three orders of magnitude. Multiscale transport coupling factors obtained via inverse calibration reduced model–experiment discrepancies to 0.05 V, validating the framework for EHC electrode design. Full article

Hydrogen peroxide fuel cells have emerged as a promising class of electrochemical energy conversion device owing to the dual redox character of H₂O₂, its liquid-phase storage, and its ability to operate in air-free environments. In this work, a dual-compartment direct H₂O₂ fuel cell using a Prussian Blue cathode and a tantalum anode, separated by a Nafion 115 proton exchange membrane, was systematically characterized and optimized with respect to electrolyte pH and ionic composition. The influence of pH on OCV was investigated independently in each compartment across the range of pH 2 to 12. In the tantalum compartment, OCV increased non-linearly with pH from 573 mV to 808 mV, driven by the enhanced electrochemical reactivity of the system under alkaline conditions. In the Prussian Blue compartment, OCV decreased from 676 mV to 199 mV with increasing pH, reflecting the instability of the material in alkaline conditions. The effect of the electrolyte ionic composition on average current density was subsequently investigated by varying the concentrations of NaCl and Dy(NO₃)₃. Increasing NaCl from 0 to 2.5 M produced an increase in current density from 0.414 mA/cm² to 0.973 mA/cm², consistent with ohmic resistance reduction through improved ionic conductivity. The addition of Dy(NO₃)₃ produced a positive response with an optimal concentration of $0.05$ M, at which current density reached 1.08 mA/cm², before declining sharply. Under the fully optimized conditions, pH 12 in the tantalum compartment, pH 2 in the Prussian Blue compartment, 0.3 M H₂O₂, 2.0 M NaCl, and 0.05 M Dy(NO₃)₃, the cell produced an OCV of 724 mV and a peak power density of 0.283 mW/cm² at a current density of 0.8 mA/cm². These results demonstrate that meaningful electrochemical performance can be achieved in a dual-compartment H₂O₂ fuel cell without the use of precious metal catalysts and highlight electrolyte engineering as an effective strategy for improving cell output in this class of device. Full article

This study aims to investigate the performance and mechanism of N′-[(E)-phenylmethylidene] furan-2-carbohydrazide (FNH), a hydrazone Schiff base, as a corrosion inhibitor for carbon steel in 1.0 M HCl. The research was conducted by coupling electrochemical testing (Tafel analysis and Impedance spectroscopy) with surface characterization (SEM and AFM) and advanced computational tools, including quantum-chemical modeling and classical molecular dynamics (MD) simulations. Tafel analysis revealed that FNH acts as a mixed-type inhibitor, concurrently slowing iron oxidation and hydrogen reduction. Impedance data showed that the Faradaic resistance grew monotonically with FNH dosage, reaching 95% protection at 1 × 10⁻⁴ M. Fitting the results to the Langmuir model indicated a joint physical–chemical anchoring pathway, further confirmed by SEM/AFM inspection which disclosed a uniform organic deposit. Quantum-chemical modeling revealed that protonated species broaden the molecule’s capacity for bidirectional electron exchange, while MD simulations on the Fe (110) slab confirmed a flat-lying geometry that maximizes heteroatom–metal contact. The consistency between laboratory observables and atomic-scale predictions provides a detailed, mechanism-oriented picture of how this organic protective layer curtails acid corrosion. Full article

Background and Objectives: Head and neck cancers are heterogeneous malignancies with variable biological behavior and treatment response, contributing to high morbidity and mortality. Conventional imaging techniques are limited in their ability to capture tumor biology, highlighting the need for advanced functional imaging. This review aims to evaluate the role of multiparametric magnetic resonance imaging (MRI) in characterizing the tumor microenvironment. Materials and Methods: A narrative review was conducted based on a targeted literature search of databases, including PubMed and Google Scholar. Studies addressing advanced MRI techniques for assessing tumor cellularity, vascularity, molecular features, and oxygenation were selected and analyzed. Results: Perfusion techniques, such as dynamic contrast-enhanced MRI (DCE-MRI) and arterial spin labeling (ASL), provide a quantitative assessment of tumor vascularity and show value in predicting treatment response. Diffusion-based methods, including diffusion-weighted imaging (DWI), intravoxel incoherent motion (IVIM), and diffusion kurtosis imaging (DKI), enable evaluation of tissue cellularity and heterogeneity. Molecular approaches, such as chemical exchange saturation transfer (CEST) and amide proton transfer (APT), offer insights into protein content and proliferation. Oxygenation-sensitive techniques, such as blood oxygenation level dependent MRI (BOLD MRI) and oxygen-enhanced MRI (OE-MRI), allow non-invasive assessment of tumor hypoxia. Conclusions: Multiparametric MRI provides a comprehensive and biologically relevant evaluation of the tumor microenvironment in head and neck cancer, with potential to improve treatment prediction and support personalized therapeutic strategies. Full article

The widespread use of proton pump inhibitors (PPIs) in clinical practice has increased the number of related hypersensitivity reactions (HSRs). The active ingredient is not always responsible for the reaction. In some cases, HSRs may be related to the excipients contained in the drug. The adverse reactions to anti-SARS-CoV-2 vaccines have drawn the scientific community’s attention to the potential roles of excipients such as polyethylene glycol (PEG) and polysorbate 80. We present a case of a patient with three anaphylactic reactions following the administration of the anti-SARS-CoV-2 vaccine and a history of HSR to omeprazole. Through an in-depth medical history and allergy testing, we found that the patient was sensitized to PEG contained in the vaccine and to the omeprazole formulation used. We also conducted a mini-review of the literature, reporting all cases of reactions to PPIs, both related to the active ingredient and to excipients. Adverse reactions to PPIs are rare but still increasing. To our knowledge, this is the first reported case of anaphylaxis to PPI-related PEG. Some excipients are widely used in commonly used products, including non-pharmaceuticals. Therefore, in patients with multiple episodes of anaphylaxis, it appears necessary to exclude a possible allergy to excipients. This could ensure a greater safety and a better quality of life. Full article

Proton exchange membrane fuel cells (PEMFCs) exhibit high energy efficiency and rapid load response, but challenges are faced in membrane fabrication, including the need for renewable resources and cost-effective, non-toxic solvents. This study analyzes the morphological and structural properties of perfluorosulfonic acid (PFSA) ionomer membranes, FS-930 and F-14100, after the dissolution of membranes via ratios of 50:50, 80:20, and 20:80 by volume of dimethyl sulfoxide (DMSO) and water. Bode plot analysis indicates that membranes rich in DMSO show lower frequency phase angle peaks, suggesting better segmental motion and ionic conductivity. Additionally, higher DMSO content correlates with broader FTIR peaks, reflecting enhanced solute–solvent interactions. The untreated FS-930 membrane demonstrates significant intensity peaks linked to semi-crystalline domains, indicating strong baseline conductivity. SEM analysis revealed surface roughness variations in FS-930 linked to different water-to-DMSO volume ratios. DMSO-rich mixtures produced dense, hydrophobic PFSA membrane structures, whereas water-rich mixtures increased water uptake and ionic conductivity. Fumapem F-14100 showed superior hydration and proton conductivity compared to FS-930 because it contains more sulfonic acid groups. These findings are critical to understanding how membrane properties relate to solvent composition, aiding in the optimization of membrane fabrication for better performance and durability in fuel cells. Full article