Search Results (9,929)

Emergency Medical Services (EMS) personnel require exceptional spatial awareness and rapid decision-making within the confined environment of an ambulance. While Virtual Reality (VR) offers a safe alternative to traditional training, the lack of high-fidelity, regionally accurate, and VR-optimized 3D ambulance models limits its application. This study presents a scenario-driven methodology for developing a VR-ready 3D ambulance environment prototype tailored for Emergency Medical Technician (EMT) training. Utilizing reality-capture techniques, terrestrial laser scanning was performed to accurately document the interior of a standard Hungarian ambulance simulator. The resulting point cloud underwent systematic processing, manual retopology, PBR shading, and the implementation of a custom dual-rigging animation system to optimize complex mechanical movements—such as stretcher operations—for standalone VR platforms. The workflow successfully reduced the vertex count to 25,373 while maintaining millimeter-level spatial fidelity. Technical evaluation confirmed that geometrical, functional, and material objectives were fulfilled, whereas pedagogical implementation remains incomplete. Structural accuracy and animation readiness were verified through preliminary inspection within Blender’s VR viewport inspector. However, interactive game-engine integration remains future work, and educational effectiveness has not yet been tested with EMT learners. Overall, this workflow delivers a 3D asset foundation that establishes the necessary technical basis for subsequent software implementation and clinical evaluation. Full article

Laser powder bed fusion (L-PBF) enables the integral fabrication of thrust chamber–nozzle and injector assemblies, eliminating some assembly and welding interfaces and reducing structural redundancy. However, under this manufacturing route, as-built geometric deviations act more directly on functional features, creating new challenges for dimensional accuracy and performance stability. To address this issue, this study investigates an additively manufactured 200 N monopropellant thruster and conducts geometric-deviation characterization, deviation–performance mapping, precision allocation, and performance validation. Key forming deviations were characterized using a coordinate measuring machine, industrial CT, micro-focus CT, and confocal microscopy. A first-order geometric deviation–performance mapping model was established through CFD-based sensitivity analysis, and Monte Carlo simulation was used to evaluate performance risk. A priority evaluation system combining the process capability index (Cpk) and performance sensitivity was then developed to guide differentiated finish-machining allowance allocation, CAD model pre-compensation, and process optimization. After two closed-loop iterations, the Monte Carlo-predicted thrust nonconformance probability decreased from 8.5% to 1.2%, and the simulated injection-flow non-uniformity narrowed from ±8.7% to ±4.2%. Cold-flow measurements showed that injection-flow non-uniformity decreased from ±9.3% to ±4.8%. In the rated-condition hot-fire test of the compensated thruster, the measured steady-state thrust deviation was controlled within ±1.5%, while the throat-diameter Cpk increased from 0.56 to 1.45. These results demonstrate that the proposed “inspection–analysis–allocation–compensation” closed-loop method can integrate performance sensitivity with actual manufacturing capability and provide an implementable route for precision-resource allocation and engineering optimization of integrated additively manufactured propulsion components. Full article

Graphene nanoplatelets (GNPs)-reinforced AlSi10Mg composites were fabricated by selective laser melting (SLM), and their corrosion resistance was systematically investigated as a function of GNPs content (0, 0.1, 0.3, and 0.5 wt.%) and corrosion duration. In the short term (≤30 days), the corrosion resistance followed the order: 0.1 wt.% GNPs/AlSi10Mg > 0.3 wt.% GNPs/AlSi10Mg > 0.5 wt.% GNPs/AlSi10Mg > AlSi10Mg. The 0.1 wt.% composite exhibited the best performance, attributed to the uniform dispersion of GNPs that filled micropores and microcracks to form a physical barrier against corrosive ions, along with favorable interfacial bonding that hindered crack growth and reduced corrosion pathways. After 60 days of exposure, however, the ranking reversed to: AlSi10Mg > 0.1 wt.% GNPs/AlSi10Mg > 0.3 wt.% GNPs/AlSi10Mg > 0.5 wt.% GNPs/AlSi10Mg. EIS analysis revealed a porous electrode behavior in the low-frequency response, captured by the constant phase element in the equivalent circuit. The long-term deterioration arose from the gradual penetration of corrosive media through micropores and microcracks, which triggered galvanic corrosion between GNPs and the matrix and rendered the barrier effect ineffective. These findings demonstrate that GNPs addition increases both the number and the total area of cathodic sites in the matrix alloy, thereby accelerating corrosion under prolonged exposure. In essence, GNPs serve as a protective barrier in the short term but transition to corrosion accelerators under long-term exposure. Full article

This work examines the response of Ti-6Al-4V fabricated by wire-laser directed energy deposition (DED) to heat inputs between 175 and 350 J/mm. Microstructure, tensile behavior, and rotating-bending fatigue were evaluated. As input increased, the transverse size of columnar prior β grains rose from about 642 to 1079 μm and the mean α-lath width increased from 0.65 to 1.32 μm. The α structure consequently changed from a fine acicular/basketweave form to a coarser lamellar form with clearer colonies. Tensile and yield strengths stayed near 900 and 840 MPa, whereas elongation fell from 14.3% to 10.3%. After a 600 °C, 4 h stress relief, fully reversed fatigue tests were performed at 500 MPa (R = −1). Specimens with 175 J/mm heat input reached about 3 × 10⁷ cycles, while one with 350 J/mm fractured at roughly 1 × 10⁵ cycles. The longer life of H175 coincided with its finer interwoven α structure, closer striations, more secondary cracks, and a more tortuous crack route. Full article

This study investigated the corrosion resistance of laser-cladded AlCoCrFeNi high-entropy alloy coatings with varying TiO₂ content (0 wt.%, 0.5 wt.%, 1.0 wt.%, and 1.5 wt.%) in 3.5 wt.% NaCl solution. Optimal cladding parameters (1500 W, 40 mm/s, 11.9 g/min) were determined via orthogonal experiments. TiO₂ promoted Ti-rich BCC2-phase precipitation, increased corrosion potential (from −1.4185 V to −0.6841 V), decreased corrosion current density (from 2.33 × 10⁻⁴ to 2.28 × 10⁻⁶ A/cm²), and enhanced charge-transfer resistance. XPS analysis demonstrated that TiO₂ promoted the enrichment of FeO, Cr₂O₃, and TiO₂ components in the passive film while reducing the Al₂O₃ fraction, leading to the formation of a dense and stable composite passive film that effectively inhibited chloride ion attack. In summary, an appropriate amount of TiO₂ doping significantly enhances the corrosion resistance of laser-cladded AlCoCrFeNi HEA coatings, with the 1.5 wt.% addition being the best-performing among the investigated compositions. Full article

In this study, a stepwise strategy was adopted to regulate and control the complexing agent system of the cyanide-free alkaline zinc–nickel (Zn-Ni) electroplating solution. A Zn-Ni coating containing a quaternary complexing agent was successfully prepared on the surface of low-carbon steel to enhance the flatness and corrosion resistance of the coating. The investigated complexing agents included triethanolamine (TEA), tetraethylenepentamine (TEPA), ethylene diaminetetraacetic acid (EDTA), and potassium sodium tartrate (PST). By fixing other parameters and testing the four complexing agents one by one, TEA was finally determined to be the best single complexing agent. This substance can effectively stabilize the metal-ion deposition process. The synergistic effects of TEPA, EDTA and PST were systematically studied, and the independent contributions of each complexing agent to performance were clarified. This design enables performance differences to be directly attributed to the inherent characteristics of each complexing agent category. The surface morphology of the sample was characterized by scanning electron microscopy (SEM). The cross-sectional morphological characteristics were analyzed by a laser scanning confocal microscope (LSCM). The chemical composition and phase composition of the samples were determined by X-ray diffraction (XRD), while the corrosion behavior of the samples was studied by electrochemical techniques, including electrochemical impedance spectroscopy (EIS) and Tafel curves. Characterization shows that when the molar ratio of EDTA to PST is 1:4 and TEA and TEPA are used in combination, the grain size of the coating is smaller, the surface is smoother, and the number of surface micropores is significantly reduced compared with coatings prepared by other complexation systems, thereby improving the flatness and corrosion resistance of the coating. Full article

Objective: Implantoplasty smoothens exposed implant surfaces but disrupts the titanium oxide layer, reducing corrosion resistance, increasing ion release, and facilitating bacterial colonization. Restoring a stable and biologically favorable surface is therefore critical. Chemical agents capable of repassivating titanium may enhance surface integrity and antibacterial performance, yet the optimal agent remains unclear. This study evaluated the repassivation effects of common disinfectants on corrosion resistance, ion release, cytotoxicity, and antibacterial activity. Methods: One hundred twenty-eight discs underwent manual implantoplasty and were treated with citric acid (CA), ethylenediaminetetraace acid (EDTA), hydrogen peroxide (H₂O₂) or saline (S). Surface topography and wettability were analyzed using white-light interferometry and contact angle measurements. Corrosion behavior was assessed via open-circuit potential monitoring and potentiodynamic polarization in Hank’s solution. Titanium ion release was quantified over 21 days using inductively coupled plasma mass spectrometry. Cytotoxicity was evaluated in human fibroblast and osteoblast cultures exposed to sample extracts. Bacterial adhesion and viability of Streptococcus sanguinis and Pseudomonas aeruginosa were analyzed by scanning electron microscopy and confocal laser scanning microscopy after 24 h and 48 h. Results: H₂O₂ increased surface roughness, while CA and EDTA showed no effect. All agents enhanced hydrophilicity, with CA and H₂O₂ producing the greatest increase in surface energy. CA showed the highest corrosion resistance and lowest ion release. No treatment exhibited cytotoxicity, and all reduced bacterial adhesion, with CA and H₂O₂ showing superior bactericidal activity. Conclusions: CA and H₂O₂ improved surface properties after implantoplasty, with CA providing the most favorable combination of corrosion resistance, minimal ion release and antibacterial effect. Full article

Background & Objectives: Laser lithotripsy is the standard energy source for mini-percutaneous nephrolithotomy (mini-PCNL). Although Holmium:YAG (Ho:YAG), Thulium Fiber Laser (TFL), and pulsed Thulium:YAG (p-Tm:YAG) are currently available for clinical use, direct comparisons among all three laser technologies are lacking. This study aimed to compare the efficacy, safety, and procedural performance of Ho:YAG, TFL, and p-Tm:YAG during mini-PCNL. The primary endpoint was the stone-free rate (SFR). Secondary outcomes included complications, operative time, lasing time, total energy delivered, and laser-related procedural metrics. Methods: Consecutive patients treated with p-Tm:YAG during mini-PCNL for renal stones were prospectively enrolled and compared with two cohorts from our institutional database treated with Ho:YAG or TFL. All procedures were performed using the same mini-PCNL technique and predefined laser settings selected to achieve the closest technically feasible match among the three platforms. Results: Ninety patients were included (30 per group). No significant differences in SFR were observed among Ho:YAG, TFL, and p-Tm:YAG (p = 0.93), or in overall complication rates (p = 0.93). After adjusting for stone volume, density, composition, and location, the laser platform was not independently associated with SFR, whereas stone volume was the only independent predictor of stone-free status. TFL exhibited a significantly longer operative time than Ho:YAG and a longer lasing time than both Ho:YAG and p-Tm:YAG, and was associated with greater total energy delivery, lower ablation efficiency, and lower ablation speed. Conversely, p-Tm:YAG demonstrated a significantly shorter lasing time than TFL and an ablation efficiency similar to that of Ho:YAG, with lasing time and ablation speed values between those observed with Ho:YAG and TFL under the evaluated settings. Laser efficacy did not differ significantly among the three groups. Conclusions: No significant differences in stone-free or safety outcomes were observed among the three laser platforms in mini-PCNL. Although significant differences were observed in lasing time, ablation speed, and energy utilization, p-Tm:YAG demonstrated an intermediate procedural profile under the operating parameters evaluated in this study. Overall, the present findings suggest that p-Tm:YAG represents a feasible treatment option for mini-PCNL, although larger randomized studies are needed before firm conclusions regarding relative platform performance can be drawn. Full article

Despite extensive research on iron-based metal matrix composites (Fe-based MMCs), an integrated assessment linking fabrication methods, reinforcement architectures, interface engineering, and strengthening mechanisms remains limited. This review summarizes recent advances in Fe-based MMCs, with emphasis on the relationships among processing routes, microstructural evolution, reinforcement characteristics, and mechanical performance. Powder metallurgy, casting, and additive manufacturing are critically compared in terms of their processing characteristics, advantages, limitations, and suitability for iron-based systems. The effects of reinforcement size, morphology, distribution, and volume fraction on composite performance are discussed. Particular attention is given to interface engineering strategies and architectured core–shell reinforcements produced through in situ reactions and solid-state diffusion, infiltration, laser cladding, sol–gel coating combined with additive manufacturing, electrochemical synthesis, and high-energy ball milling. Recent studies indicate that core–shell architectures can offer enhanced control of reinforcement–matrix interactions by combining hard ceramic or carbide phases with more ductile metallic components. Rod-like Me@MeC/Fe (Me = Ta, Nb, W) architectures and dispersed core–shell particles show promising combinations of strength, toughness, and wear resistance, although their performance depends strongly on shell architecture, interface characteristics, and processing conditions. Remaining challenges include reproducible and scalable fabrication, shell architecture control, interface stability, and long-term performance. Further progress may benefit from advanced reinforcement design, additive manufacturing, modelling, and AI-assisted optimization of high-performance Fe-based MMCs. Full article

Background: Genitourinary syndrome of menopause (GSM) is a common consequence of hypoestrogenism that negatively affects vulvovaginal health, sexual function, and quality of life. Evidence comparing non-hormonal treatment options in women with hormone-dependent malignancies remains limited. This study evaluated patient-reported outcomes following non-ablative Er:YAG laser therapy or hyaluronic acid vaginal gel in women with hormone-dependent cancer and GSM. Methods: In this prospective randomized pilot study, 65 women with hormone-dependent malignancies and GSM were randomized to receive either three sessions of non-ablative Er:YAG vaginal laser therapy (n = 34) or 0.2% hyaluronic acid vaginal gel applied intravaginally every 72 h for two months (n = 31). The primary outcome was change in the total Vulvovaginal Symptom Questionnaire (VSQ) score; change in the total Female Sexual Function Index (FSFI) score was a secondary outcome, and domain-level analyses were exploratory. Outcomes were assessed at baseline and one month after treatment. Wilcoxon signed-rank and Mann–Whitney U tests were used for the principal analyses; adjusted analyses were performed using ANCOVA. The study was retrospectively registered at ClinicalTrials.gov (Identifier: NCT07420647; first posted on 19 February 2026). Results: Within-group improvements were observed under both active interventions. The primary between-group comparison showed no difference in total VSQ change (p = 0.398). Total FSFI change favored laser therapy in the unadjusted between-group comparison (p = 0.034), and the exploratory baseline-adjusted difference was 2.72 points (95% CI, 0.19–5.25; p = 0.036). Domain-level analyses were exploratory and were not adjusted for multiplicity. Conclusions: In this active-comparator pilot study, total VSQ change was comparable between groups and the adjusted total FSFI estimate favored laser therapy. Without a sham or untreated control, within-group changes cannot establish intervention-specific efficacy; these comparative findings require confirmation in larger controlled trials. Full article

Laser-assisted trophectoderm (TE) biopsy is typically performed with millisecond diode lasers, where thermal effects remain a major safety concern. Femtosecond lasers offer a fundamentally different interaction regime, but their safety profile for TE biopsy has not been evaluated. This study aimed to assess the potential of a femtosecond laser as a tool for TE biopsy in CD1 mouse blastocysts. Biopsies were performed using single pulses at a wavelength of 514 nm with peak intensities of 5.3–16 TW/cm². The number of pulses required to separate TE samples of different isthmus widths was quantified. The study of biological effects included reactive oxygen species (ROS) and heat-shock proteins (HSP70). Laser exposure at 16 TW/cm² enabled an efficient TE biopsy within a clinically relevant number of pulses, without increasing ROS levels and with only limited HSP70 elevation, consistent with an adaptive stress response. A total of 417 embryos were transferred to pseudopregnant females to assess implantation and developmental outcomes. Implantation rates (25.8% vs. 29.6%) and the distribution of developmental outcomes (normal embryos, developmental delay and resorption) did not differ significantly between biopsied and non-exposed blastocysts in the control groups. This supports the further evaluation of femtosecond source as a tool for preimplantation genetic testing procedures. Full article

Background/Objectives: Electrotherapy encompasses diverse therapeutic modalities used in Physical and Rehabilitation Medicine, but pediatric evidence varies substantially across modality–indication pairs. This structured narrative review mapped the available pediatric clinical evidence and provided a clinically structured synthesis of clinical applications, treatment parameters, reported therapeutic outcomes, safety, and evidence gaps in pediatric rehabilitation. Methods: PubMed, Scopus, and Web of Science were searched for publications from 1 January 2000 to 17 July 2026. Evidence was synthesized by electrotherapy modality and clinical indication and classified using Oxford Centre for Evidence-Based Medicine (OCEBM) Levels of Evidence. Formal methodological quality and risk-of-bias appraisal using A Measurement Tool to Assess Systematic Reviews 2 (AMSTAR 2) and Risk of Bias 2 (RoB 2) was performed for the evidence underpinning OCEBM Level 1 classifications; no formal GRADE certainty-of-evidence assessment was performed. Results: A comparatively more developed pediatric evidence base was identified for radial extracorporeal shock wave therapy (rESWT) in cerebral palsy-related spasticity; transcutaneous electrical nerve stimulation (TENS) and interferential current therapy (IFC) in bladder and bowel dysfunction; and neuromuscular electrical stimulation (NMES)/functional electrical stimulation (FES), repetitive transcranial magnetic stimulation (rTMS), and transcranial direct current stimulation (tDCS) for selected motor rehabilitation outcomes. Photobiomodulation (PBM)/low-level laser therapy (LLLT), pulsed electromagnetic field therapy (PEMF), and high-intensity laser therapy (HILT) showed promising but indication-specific evidence, whereas Transfer of Energy Capacitive and Resistive (TECAR) had preliminary adjunctive evidence. Therapeutic ultrasound and Deep Oscillation Therapy were supported by insufficient pediatric clinical evidence, while several modalities lacked eligible pediatric clinical studies. Short-term tolerability was generally favorable, but long-term safety data remain limited. Conclusions: Electrotherapy has an adjunctive role in selected pediatric rehabilitation indications, but prescription should be based on specific modality–indication pairs. The available evidence does not support comparative effectiveness conclusions between modalities. Standardized multicenter trials and long-term safety studies are required. Full article

Water-jet guided laser (WJGL) technology has gained significant attention in precision manufacturing due to its extremely small heat-affected zone. However, laser-induced water breakdown severely constrains the achievable laser power and processing efficiency. This paper presents and validates an optical solution employing a custom-designed rotationally symmetric aspheric lens. The lens is designed to generate a sequence of discrete focal points distributed along the optical axis. This configuration maintains a high average laser power while suppressing the peak power density at each individual focus below the water breakdown threshold. Theoretical modeling and ray tracing simulations confirm the superior performance of the lens in creating a controllable multi-focal beam. Experimental results demonstrate that a WJGL system incorporating the six-focus aspheric lens operates stably at 350 W. This represents a 300 W increase compared to the conventional spherical lens, which had a stable operating power limit of approximately 50 W within this experimental system. In microgroove machining experiments on NiTi alloy, the new system achieved an approximately 3.5-fold increase in groove depth and a 2.7-fold reduction in taper angle. This study provides a practical and effective beam shaping strategy to overcome the fundamental power limitation in WJGL technology. Full article

Binder-jetted metallic components retain residual porosity after sintering, which can substantially affect their mechanical and tribological performance. This study clarifies how sintering-induced pore evolution and Cu infiltration influence the wear mechanisms of binder-jetted STS316L. STS316L specimens were sintered at 1100, 1200, and 1300 °C, and corresponding Cu/STS316L composites were fabricated by molten Cu infiltration. Their microstructures and wear behavior were analyzed using Filed-emission scanning electron microscopy (FE-SEM), Energy-dispersive X-ray spectroscopy (EDS), Confocal laser scanning microscopy (CLSM), X-ray diffraction (XRD), and cross-sectional Transmission electron microscopy (TEM). As the sintering temperature increased, the relative density and hardness of the sintered specimens increased from 72.75% to 80.69% and from 194 to 243.8 HV, respectively. Nevertheless, their average coefficient of friction increased from approximately 0.25 to 0.71, while the wear width and maximum depth increased from 932.8 to 1492.0 μm and from 24.7 to 60.3 μm, respectively. Abrasive and adhesive wear predominated at 1100 and 1200 °C, whereas repeated formation, cracking, and delamination of an approximately 2.5 μm thick oxygen-rich tribolayer caused severe oxidative delamination at 1300 °C. Cu infiltration increased the relative density to 90.68–95.69%. The composites exhibited similar friction behavior, with an average coefficient of friction of approximately 0.6, and were governed primarily by adhesive wear associated with Cu transfer and plastic deformation. These results demonstrate that increased densification does not necessarily improve wear resistance and that pore structure and Cu transfer critically determine the dominant wear mechanisms. Full article

Background and Objectives: The aim of this study was to evaluate the penetration of laser-activated irrigation solutions into dentinal tubules in root canals with different degrees of curvature and different coronal flaring. Materials and Methods: Seventy-six maxillary first molar teeth previously extracted for various reasons were included in the present study. The specimens were divided into two main groups according to distal root canal curvature, determined using the Schneider method: straight (<10°) and curved (20–40°). These groups were further classified into two subgroups according to whether a coronal flaring procedure was performed (n = 19). Following root canal preparation of all specimens, final irrigation was performed using a laser activation method and an irrigation solution prepared with the fluorescent dye Rhodamine B. Horizontal apical, middle, and coronal sections of 1 ± 0.1 mm thickness were obtained from the specimens at 2 mm, 5 mm, and 8 mm from the apical foramen, respectively. The effect of the irrigation solution on dentinal tubule penetration in the root canals was evaluated in the obtained sections using confocal laser scanning microscopy. Following evaluation, the mean and maximum penetration distances into the dentinal tubules were measured. The obtained data were statistically analyzed using Generalized Estimating Equations and Bonferroni correction for multiple comparisons, with the significance level set at p < 0.05. Results: The analysis revealed that only the region factor had a statistically significant effect on mean penetration values (p < 0.001), whereas canal curvature (p = 0.010), coronal flaring (p = 0.002), and region (p < 0.001) had statistically significant effects on maximum penetration values. However, none of the two-way or three-way interactions were significant (p > 0.05). Conclusions: Coronal flaring did not affect mean dentinal tubule penetration but increased maximum penetration depth. Maximum penetration was higher in straight canals than in curved canals, while both mean and maximum penetration were significantly affected by the root canal region. Full article