Search Results (104)

Background: High-quality chest compressions are considered a fundamental component of effective cardiopulmonary resuscitation (CPR). Although body mass index (BMI) has been suggested to be associated with chest compression performance, the available evidence remains unclear, particularly among healthcare professionals evaluated under standardized training conditions. This study aimed to investigate the association between BMI and chest compression quality following standardized Basic Life Support (BLS) training in nurses. Methods: This prospective simulation study included 284 nurses who completed a standardized 45 min BLS training program. Chest compression performance was assessed individually using an AmbuMan^® Basic CPR manikin during two minutes of uninterrupted chest compressions. Adequate compression rate, adequate compression depth, and complete chest recoil were evaluated according to the manufacturer’s performance criteria based on current ERC and AHA guidelines. Participants were classified into three BMI groups: <18.5, 18.5–24.9, and ≥25 kg/m². Multivariable logistic regression was performed to evaluate the independent association between BMI and each chest compression quality parameter, adjusting for age, sex, nursing experience, previous BLS training, and working in an intensive care unit. Results: Participants with a BMI < 18.5 kg/m² had significantly lower rates of adequate compression rate (15.0%) and adequate compression depth (45.0%) than those in the other two BMI groups (both p < 0.001). Complete chest recoil also differed significantly among BMI groups (p = 0.004). After adjustment for age, sex, nursing experience, previous BLS training, and working in an intensive care unit, BMI remained independently associated with adequate compression rate (adjusted OR 1.32, 95% CI 1.18–1.49; p < 0.001) and adequate compression depth (adjusted OR 1.29, 95% CI 1.14–1.47; p < 0.001), but not with complete chest recoil (adjusted OR 1.12, 95% CI 0.99–1.26; p = 0.072). Conclusions: Following standardized BLS training, nurses with a BMI < 18.5 kg/m² showed lower rates of adequate compression rate and depth than those with higher BMI values, while BMI was not independently associated with complete chest recoil. These findings suggest an association between lower BMI and poorer performance in selected chest compression parameters within this simulation setting. Full article

Droplet impact on curved porous media involves coupled spreading, wrapping, recoiling, and penetration. A three-dimensional level set model was developed in COMSOL and validated using high-speed imaging experiments to quantify axial and circumferential spreading lengths, central liquid film height, penetration depth, and energy partitioning at maximum spreading. As the We increased from 10 to 40, the maximum axial and circumferential spreading factors increased by 15.58% and 25.80%, respectively, while viscous dissipation increased by 17.32% and the recoiling-stage peak central liquid film height decreased by 16.70%. Increasing porosity from 0.4 to 0.6 had little effect on macroscopic spreading but raised the penetration peak and reduced the recoiling-stage liquid film height by 18.25%; similarly, increasing particle diameter from 0.15 to 0.25 mm increased the penetration depth at 20 ms by 49.75%, by reducing Darcy–Forchheimer resistance. Increasing surface tension from 0.0273 to 0.1092 N/m reduced the peak axial and circumferential spreading factors by 26.08% and 36.49%, respectively, whereas increasing viscosity from 0.003 to 0.009 Pa·s reduced the peak axial spreading factor and penetration peak by 15.96% and 45.95%. These results demonstrate that pore-scale parameters and liquid properties jointly regulate droplet impact on curved porous media, with pore structure affecting penetration and liquid properties controlling spreading and recoiling. Full article

Boron neutron capture therapy (BNCT) is a radiotherapeutic modality that enables tumor-targeted cell killing. The nuclear capture reaction between boron-10 (¹⁰B) and low-energy thermal neutrons produces high linear energy transfer (LET) particles (α-particles and recoiling lithium nuclei), each of which have short path lengths within the diameter of a single mammalian cell. The deposited energy creates clustered DNA double-strand breaks that are cytotoxic in these tumor cells while sparing the surrounding healthy tissues. This advantage makes BNCT a highly attractive treatment modality compared to conventional radiotherapy. Nevertheless, despite its theoretical precision, the clinical translation of BNCT remains constrained by suboptimal tumor-selective boron delivery; insufficient intracellular accumulation; and heterogeneous biodistribution profiles associated with conventional small-molecule-based boron agents, such as boronophenylalanine (BPA) and sodium borocaptate (BSH). While the development of new accelerator-based neutron sources (ABNSs) has renewed interest in BNCT, effective ¹⁰B delivery remains a major challenge. To address this, nanomedicine has been steadily on the rise in cancer research. In recent years, nanocarrier-based delivery systems have emerged as a transformative alternative delivery strategy. Nanodrugs offer several advantages over conventional small-molecule drugs, such as improved solubility, increased plasma half-life, enhanced permeability and retention in tumors, and active targeting, as well as decreased systemic toxicity and drug resistance. In recent years, nanocarrier-based delivery systems have emerged as a transformative strategy for ¹⁰B delivery. In this focused review, we will discuss various types of nanocarriers used for boron drug delivery that enhance boron loading efficiency and evaluate what enables their selective delivery to and accumulation within tumor cells. Full article

Background: Actinium-225 (²²⁵Ac) is receiving major attention as the radionuclide of choice for targeted alpha therapy (TAT) due to its outstanding physical properties such as a long physical half-life of 9.9 days and a short range of alpha (α)-particles which are responsible for the destruction of malignant tumors, whilst sparing normal surrounding tissues. Although the physical properties of ²²⁵Ac make it a desirable radionuclide for TAT, its application is challenging due to the lack of chelators available to stabilize its daughter radionuclides, resulting in the recoil effect. This occurs when there is a breakdown between the radionuclide and the chelator, therefore minimizing the therapeutic effects of the radiopharmaceutical. Nanodrug delivery systems (NDDSs) may minimize the challenge of ²²⁵Ac’s recoiling daughters and increase tumor penetration. Aim: This study aimed at using poly(lactic-co-glycolic)acid (PLGA) and chitosan (CS) nanoparticles as a delivery vehicle for targeted alpha therapy of prostate cancer in order to increase the therapeutic effect of ²²⁵Ac PSMA617-TFA. Methods and Results: PLGA nanoparticles were prepared using a nanoprecipitation method, after which they were functionalized with chitosan and folic acid. Following synthesis of ²²⁵Ac PSMA617-TFA, the radiopharmaceutical was loaded onto the nanoparticles. SEM analysis and FTIR were performed for characterization of the nanoparticles, and in-vitro drug release of ²²⁵Ac PSMA617-TFA at pH = 6.5 and pH = 7.4, respectively, was measured. The nanoparticles prepared had an average size of 200 nm and had a positive charge. This was further confirmed using a zetasizer and with scanning electron microscope (SEM) analysis. The PLGA-CS nanoparticles indicated a high encapsulation efficiency after 24 h. The results also showed a controlled release of ²²⁵Ac PSMA617-TFA over 72 h. The results of this study indicate that PLGA-CS nanoparticles are suitable for retaining ²²⁵Ac and its recoiling daughters (²²¹Fr and ²¹³Bi) at the tumor site, potentially providing a platform for future therapeutic evaluation. Conclusions: The results of this study indicate that PLGA-CS nanoparticles demonstrate feasibility as a drug delivery vehicle for ²²⁵Ac PSMA617-TFA, with effective retention of ²²⁵Ac and its decay daughters. However, biological validation through in vitro cellular studies and in vivo preclinical models is required before therapeutic effectiveness can be established. Full article

Geant4 (version 11.3.2) simulations were used to study particle-dependent radiation interaction in MAPbI₃ under electron, photon, and neutron irradiation. The analysis focused on spatial distributions of interaction events, released energy, secondary-particle generation, and process-specific contributions. A 1 mm single-layer MAPbI₃ target was used to identify the intrinsic material response, while multilayer MAPbI₃ containing detector geometries were considered to assess device-like effects. Electrons produced extended charged particle tracks governed by direct energy loss and secondary-electron cascades. Photons showed weak direct energy deposition, with the response mainly controlled by secondary electrons generated in discrete electromagnetic interactions. Neutrons produced sparse but locally intense energy-release patterns dominated by recoil particles and nuclear-reaction products. The results show that total released energy alone is insufficient to describe radiation response in MAPbI₃; spatial morphology and the balance between primary and secondary contributions are essential for interpreting both detector operation and possible radiation-induced degradation. Full article

Effective thoracic surgery requires timely, predictable operative lung collapse. During one-lung ventilation (OLV), lung collapse is not merely a mechanical consequence of nonventilated lumen opening but a phase-dependent physiological process. Rapid phase I collapse is driven by elastic recoil and passive gas venting, whereas slower phase II collapse depends on residual alveolar gas absorption. Communication between the operative-side airway and the atmosphere before pleural opening may permit tidal gas movement, ambient air entrainment, and nitrogen re-entry during the closed-chest period, delaying subsequent absorption collapse. This narrative review reorganizes lung collapse strategies, including denitrogenation, operative-side airway occlusion, preemptive OLV, disconnection, bronchial suction, and the open-clamp airway technique, according to timing and physiological target. Before pleural opening, alveolar nitrogen should be reduced and ambient air entrainment prevented. Around the pleural opening, airway patency and brief suspension of positive-pressure ventilation may preserve elastic recoil venting. During OLV maintenance, re-clamping or limiting atmospheric communication may support residual gas absorption. This phase-based framework interprets recent clinical findings as interventions acting before, during, and after pleural opening. This may help clinicians select strategies according to the lung isolation device, oxygenation reserve, and surgical environment, although standardized endpoints and component-level validation remain necessary. Full article

Premature structural failure of biodegradable vascular stents (BVSs) induced by stress corrosion cracking (SCC) remains a critical challenge. Heterogeneous plaques compress the stent, leading to inadequate expansion and inducing stress concentration that exacerbates SCC. This study proposes variable-stiffness stents to improve radial support and mitigate non-uniform degradation. The stents were designed with shortened axial ring segments and selective strut widening at the stenotic regions for targeted stiffness enhancement. They were virtually deployed in arteries with non-calcified and calcified plaques to evaluate immediate performance, while long-term service behavior was assessed via degradation simulation under combined electrochemical corrosion and SCC effects. The results show that variable-stiffness stents exhibited comparable residual stenosis to uniform-stiffness stents with identical local structures at plaque regions. Dual-stiffness designs yielded a smoother luminal profile than uniform-stiffness counterparts, and gradient-stiffness designs achieved further improvements. Local strut widening extended full recoil time, with a more marked effect on high-stiffness segments, by 52.6% and 41.2% in non-calcified and calcified plaques, while simultaneously increasing volume loss to mitigate non-uniform degradation. In addition, widened gradient-stiffness designs further prolonged the stable support time by 9.7%. These findings show variable-stiffness stents with widened gradient-stiffness design exhibit a more favorable immediate and long-term performance. Full article

Background: Out-of-hospital cardiac arrest (OHCA) remains a major public health problem. Many patients contact primary health care (PHC) services shortly before cardiac arrest, yet data on PHC staff preparedness to provide guideline-concordant basic life support (BLS) remain limited. This study assessed BLS knowledge and chest compression quality among medical and non-medical PHC staff. Methods: This multicentre cross-sectional simulation-based study was conducted in Poznań and Poznań County, Poland. PHC staff with direct patient contact were included (n = 162). Assessment comprised an author-developed 15-item knowledge test based on European Resuscitation Council guidelines and a two-minute continuous chest compression trial on a Resusci Anne QCPR manikin. Correlations were analysed using Spearman’s rank correlation coefficient, group differences using the Kruskal–Wallis test with Dunn–Bonferroni post hoc comparisons, and predictors using multivariable linear regression. Results: The median BLS knowledge score was 9/15 points (mean 8.74). Mean chest compression depth was 41.3 mm, below the recommended range, with only 23.5% of compressions meeting depth criteria. Correct compression rate was maintained in 30.2% of compressions, and full chest recoil was observed in 55.0% of attempts. Age was negatively correlated with compression rate. In participant-level regression, higher BLS knowledge was associated with better QCPR performance; however, this association was attenuated and no longer statistically significant in mixed-effects models accounting for clustering by practice. Conclusions: PHC staff demonstrated gaps in BLS knowledge and inadequate simulated chest compression performance, particularly regarding compression depth and rate. These findings support recurrent, simulation-based BLS training for all PHC personnel. Full article

Al₂O₃ single beads were deposited on a Ti-6Al-4V (Ti64) substrate by laser-directed energy deposition (DED-LB) to establish baseline process conditions for ceramic protective layers and future Ti64/Al₂O₃ functionally graded materials (FGMs). These ceramic-containing surface layers are applicable to titanium components requiring improved oxidation, wear, and thermal resistance in aerospace, automotive, and high-temperature structural applications. Laser power (300–700 W) and scan speed (300–700 mm/min) were varied, and bead geometry was quantified from cross-sectional observations; energy density and dilution ratio were calculated. Melt pool depth increased with higher power and lower speed, indicating increased heat input and substrate melting. Crack formation in the melt zone was more sensitive to laser power than to scan speed. In contrast, bead height showed a non-monotonic response to energy density, which may be associated with possible coupled effects such as recoil pressure-driven melt pool disturbance, powder scattering, and insufficient powder melting at high scan speeds. Dilution-based optimization identified 300 W laser power and 400 mm/min scan speed, with a powder feed rate of 3 g/min, as the most suitable condition within the investigated process window, giving the lowest practical dilution ratio of approximately 40.27%. SEM–EDS and XRD analyses were conducted to examine the interfacial microstructure and phase characteristics under the selected condition. Overall, this study provides fundamental process guidelines and mechanistic insight into bead formation, dilution behavior, and interface formation, supporting the future application of DED-LB-based ceramic protective or graded layers on Ti64 surfaces. Full article

We study the projected sensitivities of the Jiangmen Underground Neutrino Observatory (JUNO) and the Deep Underground Neutrino Experiment (DUNE) to cosmic-ray-produced dark mesons in a confining dark sector with a leptophobic vector portal. Using the same atmospheric dark meson flux framework as in our previous JUNO study, which includes proton bremsstrahlung, Standard Model meson decays, and Drell–Yan production followed by dark hadronization described by a modified Quark Combination Model, we perform a controlled comparison between JUNO and DUNE within a common source-side setup. Our results indicate that JUNO achieves stronger overall sensitivity across most of the parameter space, primarily because its inclusive event-level visible-energy criterion efficiently retains soft elastic recoils. In contrast, DUNE demonstrates systematically larger visible effective cross sections in the deep-inelastic scattering (DIS) channel, where energetic final states readily exceed its particle-level hadronic thresholds. Moreover, kinematic hardening of elastic recoils at heavier mediator masses ($m_{Z^{\prime }}\gtrsim 1$ GeV) and higher incident energies ($E_{K_D}\gtrsim 1$ GeV) further enhances DUNE’s elastic acceptance. Nevertheless, over most of the benchmark parameter space considered here, JUNO yields a larger total signal rate because the incident dark meson flux peaks sharply at low energies, favoring the soft elastic regime. Consequently, this interplay between flux distribution and detector thresholds causes the sensitivity gap between JUNO and DUNE to narrow significantly in the heavy-mediator regime. Full article

The surface properties and electrical behavior of carbon-based materials can be effectively modified by energetic ion irradiation. In the present study, graphene oxide (GO) and cyclic olefin copolymer foils (COC, Topas 112 and 011, respectively) were irradiated with 1 MeV Au ions using a 3 MV Tandetron accelerator at fluences of 1 × 10¹⁴, 1 × 10¹⁵, and 2.5 × 10¹⁵ cm⁻². The irradiation induced systematic modifications in surface chemistry, morphology, wettability, and electrical properties. Composition changes were investigated using Rutherford backscattering spectrometry (RBS) and elastic recoil detection analysis (ERDA), while surface morphology and roughness were characterized by atomic force microscopy (AFM). This revealed a clear fluence-dependent evolution of nanoscale topography. The vibrational characteristics were assessed through Raman spectroscopy, and the chemical composition of the surface layers was analyzed by X-ray photoelectron spectroscopy (XPS). The surface wettability was evaluated by static contact angle measurements, and surface free energy was determined using the Owens–Wendt–Rabel–Kaelble (OWRK) method. These measurements showed a consistent decrease in water contact angle and an increase in surface free energy with increasing ion fluence in the COC substrates, whereas GO exhibited a distinct response. Electrical characterization demonstrated a pronounced fluence-dependent decrease in sheet resistivity in polymers. The results show that 1 MeV Au ion irradiation enables systematic and fluence-dependent modification of both surface and electrical properties. Full article

The present work uses numerical methods to explore the impact of spatial orientation on the behavior of molten pool and thermal responses during the laser–Cold Metal Transfer (CMT) hybrid additive manufacturing of metallic cladding layers. Based on the traditional double-ellipsoidal heat source model, an adaptive CMT arc heat source model was developed and optimized using experimentally calibrated parameters to accurately represent the coupled energy distribution of the laser and CMT arc. The improved model was employed to simulate temperature and velocity fields under horizontal, transverse, vertical-up, and vertical-down orientations. The results revealed that variations in gravity direction had a limited effect on the overall molten pool morphology due to the dominant role of vapor recoil pressure, while significantly influencing the local convection patterns and temperature gradients. The simulations further demonstrated the formation of keyholes, dual-vortex flow structures, and Marangoni-driven circulation within the molten pool, as well as the redistribution of molten metal under different orientations. In multi-layer deposition simulations, optimized heat input effectively mitigated excessive thermal stresses, ensured uniform interlayer bonding, and maintained high forming accuracy. This work establishes a comprehensive numerical framework for analyzing orientation-dependent heat and mass transfer mechanisms and provides a solid foundation for the adaptive control and optimization of laser–CMT hybrid additive manufacturing processes. Full article

Background/Objectives: The ¹⁰³Pd/^103mRh in vivo generator represents a promising Auger electron-emitting system, in which both parent and daughter radionuclides emit predominantly Auger electrons with minimal accompanying radiation. This study investigates the release dynamics of daughter radionuclides from the ¹⁰³Pd/^103mRh in vivo generator and evaluates the underlying mechanisms governing bond rupture and daughter retention. Methods: Cyclotron irradiation of rhodium foils was performed in two separate batches, followed by radionuclide separation using conventional wet chemistry and a novel dry distillation technique. The purified ¹⁰³Pd radionuclide was used to radiolabel DOTA-TATE, phthalocyanine-TATE, and DOTA-TOC chelators. The resulting complexes were immobilized on Strata-X and Strata-C18 solid-phase extraction columns. Scheduled elution experiments were conducted to quantify the release of the ^103mRh daughter radionuclide. Results: The measured ^103mRh release rates were 9.8 ± 3.0% and 9.6 ± 2.7% from Strata-X columns with DOTA-TATE and phthalocyanine-TATE, respectively, and 10.5 ± 2.7% and 12.0 ± 0.5% from Strata-X and Strata-C18 columns, respectively, with DOTA-TOC. These values are significantly lower than the ~100% release predicted based on the reported Auger electron yield of 186%. One explanation for this difference could be potential inconsistencies in decay data that may require correction; this needs further investigation. The results further demonstrated that delocalized π-electrons, introduced via phthalocyanine-based chelation, did not mitigate daughter release. Conclusions: The low observed daughter nuclide release represents a favorable characteristic for the future clinical translation of the ¹⁰³Pd/^103mRh Auger emitter pair. The findings support the conclusion that Auger electron cascades, rather than nuclear recoil energy, dominate bond rupture processes. Full article

Background/objectives: Tropoelastin is a highly hydrophobic extracellular matrix protein responsible for the extensibility and elastic recoil of various organs. The Windkessel effect in blood vessels dampens pressure variations during the cardiac cycle to provide continuous perfusion of tissues, such as the fragile gill capillaries in fish. The teleost-specific whole-genome duplication was followed by structural and functional divergence of the duplicated tropoelastins, of which ElnB confers the uniquely low stiffness of the bulbus arteriosus. Methods: We have examined the diversity of tropoelastins in all major fish clades by searching for tropoelastin (eln) genes in the sequenced genomes. Duplication of eln genes in tetraploid salmonids and cyprinids was examined by maximum likelihood phylogenetic analysis, and cardiac eln expression in rainbow trout was quantified by qPCR. Results: The tetraploid salmonid genomes harbor two elna genes but a single elnb, except for the tandem duplicated elnb genes in sockeye salmon and lake whitefish, while the tetraploid common carp possesses four elna and elnb genes on separate chromosomes. Rainbow trout showed strong elastin staining in the larval bulbus and ventral aorta, and the bulbar expression of elnb was 15 times higher than the ventricular levels in juvenile fish. The expression of elna1 and elna2 was also significantly higher in the bulbus, and together their transcript levels were almost similar as the elnb levels. The overall hydrophobicity of the fish tropoelastins differed considerably among the species ranging from 28.6% in Emerald rockcod ElnB to 56.3% in lesser devil ray Eln, but showed no significant difference with the tetrapods examined, except for the lower hydrophobicity of teleost ElnB. Conclusions: The inclusion of tetrapods in the analysis revealed a positive relationship between ventral aortic blood pressure and tropoelastin hydrophobicity. Full article

Cardiopulmonary resuscitation (CPR) is a vital skill for healthcare professionals, crucial in life-saving situations. More than 80% of cardiac arrest cases occur out of hospital. As the demand for competent CPR practitioners grows, the effectiveness of training methods becomes increasingly important, especially for undergraduate students preparing to enter the healthcare field. The primary objective of our study is to investigate the effectiveness of simulation-based teaching methods and by integrating innovative technologies, such as the OMNI2 simulator, to enhance practitioners’ performance and to improve the precision and objectivity of CPR instruction. A cohort of 144 undergraduate students from the Nursing School Department of the National Kapodistrian University of Athens participated in an 8 h Basic Life Support Seminar. It consisted of a 5 h theoretical instruction followed by 3 h of practical training using the OMNI2 simulator. Each student was tasked to identify cardiac arrest and to perform two cycles of CPR according to the 2021 guidelines. Metrics, including total session time, cycles performed, compression-to-ventilation ratio, compression depth, compressions and ventilations per minute, full recoil, peak inspiratory pressure, and ventilation duration, were measured and compared against the simulator’s preset targets. Statistically significant differences (p < 0.05) were observed for all outcomes. In conclusion, while simulation-based teaching has conventionally been proven effective for CPR proficiency, real-time data collected in this study reveal a disparity between anticipated and actual performance. Our research underscores the necessity of refining instructional methods to enhance skill acquisition, potentially leading to improved patient outcomes in the future. Full article