Search Results (5,071)

Background/Objectives: To compare mechanical behavior, shaping performance, and safety of an original reciprocating endodontic instrument (Reciproc^® Blue) with two visually similar replicas obtained from an online marketplace. Methods: The original Reciproc^® Blue and two replica (designated Replica 1 and Replica 2) instruments purchased from AliExpress were tested. Evaluations included torque resistance, bending resistance, cyclic fatigue resistance (all according to ISO 3630-1 standards, n = 10 per group per test), and an in vitro shaping procedure using artificial root canals in plastic blocks (5 canals per instrument, n = 10 instruments per group) were carried out. Preparation time, number of pecks, procedural errors (blockages, ledges, deformations), and instrument fractures were recorded. Surface characteristics of unused (n = 2) and used instruments (n = 2) were examined using scanning electron microscopy (SEM). Statistical analysis used one-way ANOVA, Welch ANOVA, or Kruskal–Wallis tests according to the distribution and variance pattern of each endpoint, followed by the corresponding post hoc test. Repeated use was analyzed with a linear mixed effects model and checked with a robust generalized estimating equation sensitivity analysis. Deformation-free and fracture-free event curves were compared with exploratory log rank tests. Results: The original instrument showed the highest Mf/D³ and Mt/D³ values. Overall group differences were significant for Mf/D³ (Welch p < 0.001) and Mt/D³ (Welch p = 0.001), with significant Games Howell contrasts between the original and Replica 2. Replicas showed longer cyclic fatigue life (Original 407.1 s, Replica 1 490.2 s, Replica 2 607.8 s; ANOVA p < 0.001). The original instrument had a lower average preparation time for each canal than both replicas (72.8 s vs. 95.8 s and 92.3 s; Kruskal–Wallis p < 0.001) and a lower average number of pecks (8.64 vs. 9.71 and 10.00; p = 0.008). Exploratory log rank comparisons also showed group differences in the deformation-free and fracture-free event curves (Holm adjusted p = 0.005 and p = 0.024, respectively). Both replicas failed to reach working length in 4 out of 10 cases each, with high rates of blockages (Replica 1: 7/10; Replica 2: 2/10), ledges (Replica 1 only), and deformations. The limited SEM subsample revealed severe wear of cutting edges in Replica 1. Conclusions: Both tested replicas exhibited significant deviations in mechanical behavior and markedly inferior shaping safety compared to the original Reciproc^® Blue instrument, despite superficial visual similarity. Therefore, dental practitioners should be aware that low-cost imitations may compromise clinical safety. Full article

Unmanned aerial vehicles (UAVs) extend geophysical measurements into terrain where ground access is difficult and crewed surveys are costly or operationally constrained. Their practical value, however, differs substantially among sensing methods and platform configurations. This narrative review compares UAV magnetometry, gravimetry, radiometric surveying, electromagnetic surveying, ground-penetrating radar (UAV-GPR), seismic surveying, and geological remote sensing. UAV magnetometry and geological surface mapping have the strongest evidence of established practice for defined tasks. Radiometric surveying, UAV-GPR, and several electromagnetic configurations have demonstrated field capability, but their performance depends on counting statistics, coupling, source geometry, and site conditions. UAV gravimetry has actual flight demonstrations, although large-aircraft results do not establish equivalent capability on compact platforms; UAV-assisted seismic systems remain application-specific. Across methods, useful performance depends on the complete measurement chain, particularly sensor clearance, motion and interference correction, timing, calibration, and independent validation. We identify requirements for multi-sensor interpretation and distinguish the roles and limitations of artificial intelligence in acquisition, processing, inversion, and quality control. Progress toward wider adoption should be assessed through reproducible survey performance and uncertainty, rather than payload integration alone. Full article

Conversational artificial intelligence can provide individual study support, but the educational significance of its responses depends on how they are examined and used. We develop a conceptual framework comparing Individual Chatbot Interaction and Standard Classroom Interaction, then specify a Virtual Tutor with Physical Presence as a situated implementation of shared AI inquiry. The framework draws on selected scholarship concerning mediated learning, educational dialogue, self-regulation, cognitive engagement, pedagogical agents, and AI literacy. We define the unit of analysis as an interaction episode and distinguish private consultation, shared instruction, and hybrid activities through observable criteria. The tutor is specified as an animated avatar projected by video-mapping onto a static volumetric surface in the classroom; perceived presence and learning are treated as outcomes requiring measurement. The proposed contribution is a design specification linking public AI responses, teacher orchestration, evidence-based scrutiny, and individual reflection. An explanatory pathway connects these conditions to possible cognitive and metacognitive processes, with four propositions and matched comparisons for future evaluation. A projected avatar is neither necessary nor sufficient for collective verification, and its incremental value must be tested against simpler shared interfaces. No empirical effectiveness is claimed. The framework provides a basis for investigating when a situated conversational tutor supports disciplinary understanding and critical AI use. Full article

Myelin basic protein (MBP) is released into cerebrospinal fluid during demyelination and is therefore a promising biomarker for the detection of neurodegenerative diseases such as multiple sclerosis. For the label-free detection of MBP, we developed an antifouling aptasensor based on thickness shear mode sensing. DNA aptamers were immobilized on gold-coated piezoelectric crystals functionalized with an engineered antifouling self-assembled monolayer based on 3-(2-mercaptoethoxy)propanoic acid (HS-MEG-COOH) combined with either 2-(2-mercaptoethoxy)ethanol (HS-MEG-OH) or dithiothreitol (DTT) as spacers. The binding of recombinant human MBP to the aptamer was confirmed with a corresponding decrease in resonance frequency in both phosphate-buffered saline (PBS) and artificial cerebrospinal fluid (aCSF). The aptasensor achieved a limit of detection of 11 ng mL⁻¹ in PBS and 2 ng mL⁻¹ in aCSF. PBS measurements were primarily applied to determine the aptasensor functionality, whereas experiments in aCSF evaluated MBP detection at concentrations relevant to reported levels in biological CSF. Selectivity was assessed with aptamer-free surfaces, cytochrome c, and human serum albumin (HSA) with much lower responses, while concentration-dependent MBP detection was maintained in aCSF despite the increased complexity of the matrix. The antifouling performance of the modified sensing surface was further demonstrated in aCSF by the significantly reduced frequency and dissipation responses compared to bare gold. With future validation in human cerebrospinal fluid (CSF) samples, the developed biosensor has the potential to enable sensitive, label-free detection of MBP in CSF for the identification and monitoring of neurodegenerative diseases. Full article

Bone radiopharmaceuticals have evolved from early palliative agents into integral components of targeted precision oncology and theranostics. This review comprehensively traces the historical trajectory, pathophysiological mechanisms, and clinical applications of bone-directed nuclear medicine. We contrast primary bone malignancies—which directly produce malignant osteoid matrix—with metastatic bone disease, which colonizes the endosteal niche via the RANK/RANKL/OPG axis and the metastatic vicious cycle. The molecular mechanisms governing skeletal radioisotope localization are systematically detailed, encompassing calcium mimetics (²²³Ra), inorganic phosphate integration (³²P), hydroxyapatite chemisorption (^99mTc-labeled diphosphonates), isomorphous surface exchange ([¹⁸F]NaF), and direct biomarker targeting. Furthermore, we highlight the therapeutic transition from medium-range beta-emitters to high-linear energy transfer (LET) targeted alpha therapy (²²⁵Ac), nanometer-scale Auger electron emitters, and cell-directed theranostic vectors. By unifying radiopharmaceutical chemistry, microdosimetry, and emerging artificial intelligence-driven personalized dosimetry, this review provides a strategic roadmap for advancing precision bone endoradiotherapy. Full article

This research investigates crater formation during laser ablation of polymerized UDMA–TEGDMA composites, focusing on the quantitative analysis of crater volume and depth under varying laser intensities. Two types of samples were examined: composites without gold nanorods (Au0, reference sample) and composites containing resonant gold nanorod dipole antennas (Au2, plasmonic sample), with the nanorod dimensions tuned to the frequency of the incident laser irradiation. These resonant plasmonic targets were originally developed and investigated within the NAPLIFE (Nano-Plasmonic Laser Induced Fusion Energy) Collaboration, initiated in 2019. The incorporation of resonant gold nanorods enhanced the laser-induced ablation response, resulting in larger crater volumes and greater crater depths at higher laser pulse energies. In contrast, gold nanorods with non-resonant dimensions did not exhibit comparable enhancement, demonstrating that the observed effect is associated with the resonant geometry of the nanorod dipole antennas rather than simply with the presence of gold nanoparticles. Reference-line values were used to establish baseline comparisons, while the average crater depth served as a key indicator of material removal. Building on these experimental findings, the study further integrates artificial intelligence for automated crater analysis. A deep transfer learning approach using a fine-tuned ResNet-18 model was implemented to classify high-resolution crater images of Au0 and Au2 samples. By retraining the final fully connected layer while freezing the convolutional feature extractor, the model achieved a validation accuracy of 98.7 percent, demonstrating stable convergence. The results confirm that deep learning offers a powerful and reproducible framework for high-precision classification and analysis of laser-induced surface structures, paving the way for intelligent materials diagnostics and laser-process optimization. Full article

Considering differences in the penetration and retention of polyethylene glycol with different molecular weights in waterlogged wood structures at different scales, artificially aged waterlogged wood served as the model material. A Box–Behnken response surface design was employed, using low-molecular-weight PEG with molecular weights of 400–800 and solution mass fractions of 29–41 wt.% and high-molecular-weight PEG with molecular weights of 4000–8000 and solution mass fractions of 28–44 wt.% as the independent variables, with volume shrinkage after freeze drying as the response variable for optimization. The quadratic model showed good fit and predictive reliability, with significant interactions between molecular weight and solution mass fraction in both ranges. The optimal two-stage treatment was 35.7 wt.% polyethylene glycol 600 followed by 37.5 wt.% polyethylene glycol 6000, with predicted and experimental volume shrinkage values of 2.34% and 2.43%, respectively. Polyethylene glycol 600 was distributed mainly in the cell wall regions, whereas polyethylene glycol 6000 was distributed in both the cell wall and some cell lumen regions, with relatively pronounced enrichment in some lumina; after two-stage treatment, polyethylene glycol exhibited a more uniform spatial distribution within the wood cellular structure. The optimized treatment achieved an anti-shrink efficiency of 82.91% relative to the water control group, a moisture uptake of 14.3% after 230 h at 85% relative humidity, and a bending strength of 12.97 MPa, 67.79% higher than the water control. Overall, the treatment improved dimensional stability after freeze drying while maintaining favorable moisture stability and relative bending performance. Full article

Steel surface defect detection is a critical component of industrial quality inspection based on artificial intelligence (AI). In recent years, deep learning has substantially improved the level of automation in this task. However, model performance in real production lines remains jointly affected by evaluation metrics, data organization strategies, inference and post-processing settings, and deployment conditions, resulting in limited comparability across studies, poor reusability of conclusions, and difficulties in engineering transfer. Focusing on AI-based industrial inspection scenarios, this paper presents a problem-driven narrative review of steel surface defect detection research, providing a systematic analysis centered on industrial-grade evaluation metrics, public datasets and data risks, key model mechanisms, and their industrial applicability. Particular attention is paid to recall evaluation under fixed false-positive constraints, tiling- and batch-level leakage, long-tail distributions, and annotation noise as well as issues related to input fidelity, representation against complex backgrounds, end-stage decision-making, and lightweight deployment. This review provides a problem-oriented reference framework for result interpretation, method comparison, and industrial deployment evaluation in steel surface defect detection research. Full article

Agricultural mulch films are utilized to optimize crop yields. However, their extensive use is linked to environmental drawbacks, including microplastics (MPs) formation due to aging and pesticide adsorption. This study integrated three connected aspects of mulch aging: (i) MPs’ formation from biodegradable (PBAT/PLA, TPS) and conventional (PE) films under natural/artificial aging, (ii) azoxystrobin (AZO) sorption/desorption dynamics on/from resulting MPs, and (iii) inhibitory effects of films with adsorbed AZO on Penicillium expansum growth and patulin production. MP surfaces were characterized using ATR-FTIR, SEM, and contact angle measurements. The one-year field experiment demonstrated the formation of biodegradable MPs (≥100 μm) from TPS and PBAT/PLA mulch films under the tested field conditions, while particles < 100 μm remained unquantified. Biodegradable MPs rapidly adsorbed over 85% of AZO and showed minimal desorption (<15%), with artificially aged MPs exhibiting the highest partition coefficients. By contrast, PE adsorbed AZO only after natural aging. Aged agricultural films inhibited P. expansum more strongly than pristine ones, with inhibition increasing alongside adsorbed AZO levels. Full article

This study investigates the wetting behavior of artificial substrates: polymers, metals, and glass, and natural freshwater-submerged substrata represented by Potamogeton lucens leaves, collected from shallow eutrophic lakes in northern Poland. Surface interactions were quantified by contact angle measurements and interpreted using the dynamic contact angle hysteresis formalism, with particular emphasis on the apparent surface free energy γ_SV, its polar and dispersive components, adhesive spreading pressure Π, work of adhesion W_A, and spreading W_S. These parameters characterize substrate-specific surface differences associated with aging and biofouling. Contact angles were measured using a previously developed captive bubble system, enabling the characterization of fully hydrated, heterogeneous submerged surfaces. Potential relationships between selected lake water characteristics and macrophyte surface wettability parameters were explored using Spearman’s rank correlation. Measurements of young and old leaves from three lakes revealed consistent age-associated changes in advancing contact angle and apparent surface energetic parameters. Exploratory analysis revealed potential relationships between the advancing contact angle and Secchi depth in both leaf-age groups, as well as between age-associated changes in wettability and ammonium concentration or conductivity. The results suggest that wettability analysis may help characterize submerged surface conditions and identify environmental relationships that warrant further investigation. Full article

This study evaluated the effects of dentin substrate, adhesive strategy, and resin composite type on microshear bond strength (μSBS), with particular emphasis on three-second selective dentin etching of artificially demineralized dentin (ADD). Flat midcoronal dentin surfaces from 144 human permanent third molars were allocated according to dentin substrate, adhesive strategy, and resin composite type. ADD was produced using a 14-day pH-cycling protocol. Etch-and-rinse (E&R), self-etch (SE), and three-second selective dentin etching (SDE) strategies were evaluated with a thermoviscous bulk-fill and an injectable resin composite. μSBS was tested after 24-h water storage. Data were analyzed using three-way analysis of variance and heteroscedasticity-robust HC3 tests, with Bonferroni-adjusted pairwise comparisons. Sound dentin showed higher μSBS than ADD (p < 0.001), and adhesive strategy had a significant effect (p = 0.006). SDE showed higher μSBS than SE after Bonferroni adjustment (p = 0.0246), whereas the E&R–SE difference did not meet the adjusted significance threshold (p = 0.0503). No statistically significant difference was detected between SDE and E&R. The resin composite main effect and interactions were not statistically significant. These findings concern immediate bond strength after 24-h water storage and do not establish long-term bonding performance. Full article

The Surface Water and Ocean Topography (SWOT) mission provides reservoir water surface elevation (WSE), but converting absolute WSE to storage remains sensitive to the relative reference and shape of hypsometric curves. Here, we evaluate a site-specific vertical alignment parameter and a hydrostatic-constrained extension for truncated hypsometric curves using 14 reservoirs with concurrent in-situ records and two hypsometric curves: GRDL (Global reservoir dataset through deep learning) and REGEOM (geometric approximation). Under the reference assumption that the maximum observed SWOT WSE corresponds to full capacity, the median capacity-normalized root mean square error (RMSE) is 14.9%. The reservoir-specific full-record calibration reduces this value to 2.9%, showing that effective vertical alignment is a major sensitivity. GRDL yields lower capacity-normalized RMSE than REGEOM. Artificial-truncation experiments show that the constrained extension reproduces withheld portions of tabulated curves with median reconstruction errors below 1% across the tested distances. A chronological 60/40 holdout test supports temporal generalization after local calibration: for the 11 reservoirs, the median capacity-normalized RMSE is 0.026 in both calibration and validation periods. In contrast, leave-one-reservoir-out tests find no statistically significant improvement over the reference assumption. The results therefore support locally calibrated, sampled storage retrieval while showing that transfer of a single alignment parameter to fully ungauged reservoirs remains unresolved. Full article

Exosomes are an evolved sub-type of extracellular vesicles (EVs) that have gained popularity in recent years as a novel biological nanocarrier system for targeted precision therapy in cancer owing to their excellent biocompatibility, low immunogenicity, and high stability. While other artificial systems can only deliver specific types of drug, exosomes have been found to effectively carry different types of therapeutic cargo, such as chemotherapeutic agents, proteins, peptides, mRNA, siRNA, miRNA, and even CRISPR/Cas gene editing elements. Recent progress in exosome engineering technologies, such as surface modification, donor cell modification, bionic hybrid vesicles, and stimuli-responsive exosomes, has improved their targeting efficacy, cargo-loading capacity, and controlled drug release properties. Apart from their therapeutic use, exosomes play an active role in promoting tumor development by regulating the tumor microenvironment, angiogenesis, metastasis, immune escape, maintenance of cancer stem cells, and drug resistance. This review provides a brief insight into the biological properties of exosomes, recent developments in isolation and characterization methods, engineering approaches, therapeutic cargo loading, and their uses in targeted chemotherapy, gene and RNA therapy, immunotherapy, phototherapy, sonodynamic therapy, chemo-dynamic therapy, and combinational therapy. Moreover, the existing issues in exosome research, such as exosome heterogeneity, large-scale production, quality control, and regulatory issues, are addressed. Finally, new approaches involving artificial intelligence, multi-omics technology, and personalized engineering of exosomes are presented as potential solutions to enhance the clinical use of exosomes. Full article

Pitting corrosion is a localized degradation mechanism that can significantly affect the structural integrity of steel components while remaining difficult to detect and characterize using conventional monitoring approaches. This work investigates the use of pulse-echo ultrasound and data-driven signal analysis for the observability and characterization of localized pitting in low-carbon steel. The ultrasonic response of two 20 MHz single-element contact transducers was investigated through laboratory measurements on artificial pits and physics-based k-Wave simulations spanning a wider range of pit sizes and morphologies. The results show that localized pits modify the received signal through attenuation, scattering, waveform distortion, and the generation of secondary reflections, with the observed ultrasonic response strongly dependent on pit morphology and transducer aperture. A signal-processing and feature-extraction framework was developed to analyze these changes and to evaluate pit observability prior to characterization. Using pit-free measurements, observability limits were quantified with an autoencoder trained on signal descriptors, demonstrating that pit observability is influenced predominantly by pit geometry, normalized pit width, and pit volume rather than by depth alone. For signals exhibiting sufficiently observable and specular pit reflections, time-of-flight measurements enabled pit-depth estimation for defects deeper than 300 µm. To account for propagation-path distortions affecting pit-related echoes, an empirically derived cross-path delay compensation approach was developed using Random Forest models trained on synthetic signals, reducing systematic depth-estimation errors in the synthetic dataset and providing a physics-informed framework for future quantitative characterization studies. Additional Random Forest models employing waveform descriptors and reflection-amplitude indicators were used to assess pit morphology and acoustic surface specularity. The proposed framework was evaluated using laboratory measurements and through preliminary long-term monitoring of two pre-pitted specimens deployed in the HarshLab offshore environment. In these deployments, the methodology enabled simultaneous tracking of localized pit-wall evolution and overall backwall thickness changes from the same pulse-echo measurements, illustrating the potential of the approach for monitoring localized corrosion activity alongside generalized specimen wall loss. Full article

Bisphenol A (BPA) release from polycarbonate (PC) samples representative for major outdoor applications under environmentally relevant conditions has been characterized by a recently developed artificial accelerated weathering method. It simulates typical environmental stressors through controlled exposure to UVA radiation, rain, temperature, and humidity variations in a weathering chamber. The weathering chamber was modified to a closed-loop water cycle, enabling detection of potential accumulated BPA releases from the investigated samples at ultra-trace levels and excluding contamination. Four PC materials, representative of major outdoor applications, were investigated: (i) Reference PC with low UV absorber content, (ii) coextruded PC sheet with a high UV-absorber content surface layer, (iii) UV-cured coating protected PC for automotive headlamps, (iv) thermally cured polysiloxane hard-coated PC sheet. The artificial weathering tests resulted in consistently low accumulated BPA releases of at most 0.34 mg m⁻² for samples with exposed PC surfaces. Samples with outer surfaces protected by commercial coatings revealed approximately two orders of magnitude lower releases, with cumulative BPA releases of 0.005 mg m⁻² for the UV-cured coating-protected PC and 0.003 mg m⁻² for the polysiloxane hard-coated PC. Across all cases examined, the release of BPA ceased after at most four to six weeks, corresponding to roughly 1–1.5 years of outdoor exposure in Central Europe if correlated based on applied UV radiation dose. Extended weathering for up to 11 weeks confirmed that no further BPA releases occurred after cessation. These results suggest that BPA releases from outdoor PC applications occur only during an initial weathering period and subsequently diminish to virtually zero. The observed release pattern can be plausibly explained by hydrolysis at the PC surface initially triggering minimal BPA releases, while progressive photo-degradation transforms the chemical composition in the topmost surface layer, which is hypothesized to cause the observed cessation of BPA releases. Full article