Search Results (303)

This study evaluated the effects of four cavity disinfection protocols on microtensile bond strength (µTBS) and failure mode of dentin bonded with a universal adhesive in self-etch mode. Sixty human third molars were assigned to five groups (n = 12): Control (Clearfil S3 Bond Universal), Clearfil SE Protect Bond (CPB, MDPB-containing), 2% chlorhexidine (CHX), 5.25% sodium hypochlorite (NaOCl), and 200 ppm hypochlorous acid (HOCl). After disinfectant application and bonding, composite build-ups were sectioned into beams (≈0.9 mm²) and tested as immediate (24 h) and thermocycled (10,000 cycles) subgroups. Data were analyzed using two-way ANOVA, Tukey HSD, and chi-square/Fisher’s exact tests (α = 0.05). At 24 h, NaOCl and CHX produced significantly lower µTBS than the control, HOCl, and CPB groups (p < 0.05). After thermocycling, Control, CPB, and NaOCl declined significantly, while CHX remained stable (p = 0.960) and HOCl showed non-significant reduction (p = 0.086). NaOCl yielded the highest adhesive failure rate and lowest bond strength. CHX reduced initial µTBS but maintained stability. HOCl and CPB produced values comparable to controls, though HOCl was more aging-susceptible. MDPB-containing adhesives may preserve bond durability while providing disinfection. Full article

This paper proposes a temperature measurement and system identification method for confined cavity explosions based on an improved type C thermocouple sensor. On the one hand, to address the extreme conditions caused by high-speed fragments and intense shock waves in an enclosed explosive environment, a thermocouple probe structure employing alloy strips of different widths with an alumina insulating layer in between is designed. By optimizing the strip width, the contact issues arising from edge-cutting burrs are effectively suppressed, thereby significantly enhancing the electrical insulation performance and overall reliability of the sensor. Additionally, a wedge-shaped alumina ceramic piece is designed to secure the thermocouple probe, further improving its structural stability under impact conditions. On the other hand, to tackle the highly nonlinear and multi-field coupled characteristics of the post-explosion temperature field, a system identification method based on the least square method is proposed. This method constructs a polynomial function in terms of radial distance and time variables, enabling effective reconstruction of the temperature field from limited measurement points. It provides a useful reference for understanding of the temperature distribution in confined cavity explosions and supports improved estimation of the temperature field. Finally, experimental results demonstrate that the improved sensor exhibits good survivability and measurement reliability under extreme explosive conditions. Meanwhile, the reconstructed temperature field model shows high fitting accuracy and good capability for describing the temperature distribution, confirming the effectiveness of the proposed identification method. Full article

This study investigates the breakdown of thermal symmetry in finned square cavities under natural convection, focusing on how the fin-to-fluid conductivity ratio governs heat-transfer redistribution and localization. A band-resolved statistical framework is employed to analyze hot- and cold-wall Nusselt number responses across conductivity ratios ($k_r$) ranging from symmetric to highly contrasting conditions. At $k_r=1$, the cavity exhibits a fully symmetric conduction–convection regime with complete wall-to-wall coupling and a unified thermal response. Increasing the conductivity ratio to $k_r=10$ introduces a transitional regime marked by mild but systematic asymmetry, with convective activity beginning to favor the cold wall. At $k_r=100$, the system undergoes a structural transition to a strongly asymmetric state, characterized by attenuation of hot-wall convection and sustained cold-wall dominance. Under extreme ratio ($k_r=1000$), convective heat transfer becomes highly localized at the cold wall, forming a directional thermal pathway. Joint Gaussian envelopes, regression scaling, principal component analysis, and Hotelling separation collectively demonstrate that symmetry breakdown proceeds through distinct, statistically separable stages, rather than emerging as a gradual shift in mean heat-transfer intensity. The results establish cold-wall localization as the governing physical mechanism and provide a unified framework for controlling convective heat transfer in fin-assisted natural-convection systems. Full article

Spectral demodulation is a crucial component of the extrinsic Fabry–Pérot interferometric (EFPI) sensing technology. In this study, a feedback-based linear spectral fitting demodulation method is proposed for interrogating EFPI sensors. This method utilizes a discrete function derivative and a feedback amplitude calibration technique to extract the complete spectral phase, and the cavity length of the EFPI sensor is determined by performing a linear fit to the relationship between the optical frequency and the spectral phase. The experimental results indicated a nonlinearity of 0.134% over a cavity length range of 50–260 μm, and the resolution was 6.6 nm at a cavity length of 170.210 μm. Pressure measurements obtained with the developed sensor exhibited a nonlinearity of 0.401%. Compared to traditional spectral minimum mean square error algorithms, the proposed method is simpler and faster, making it more suitable for implementation on commodity hardware and better aligned with the practical needs of engineering applications. Full article

In the optical fiber Fabry–Perot (FP) multi-dimensional acceleration sensing system, multi-dimensional acceleration measurement is realized based on a single optical path, resulting in the existence of multi-channel interference signals in the spectrum, and the traditional cavity length demodulation algorithm cannot achieve efficient separation of aliasing signals and high-precision demodulation of FP cavity length. To solve this problem, an adaptive filtering–multiple peaks–cooperative least squares algorithm (AF-MP-LS) is proposed for cavity length demodulation of optical fiber FP multi-dimensional accelerometer. The adaptive Gaussian filter is used to dynamically adjust the parameters according to the frequency difference in the aliasing optical signal, and the interference spectra of each channel are efficiently separated. The multiple peaks–least squares method is used to demodulate the separated signals, improve the demodulation resolution, and solve the problem of limited dynamic range of spectral signals. Furthermore, based on the multiplexing structure, a complementary correction method utilizing ‘triple-interferometric’ information—derived from the FP cavities and the auxiliary Michelson interference component—is proposed to improve the demodulation accuracy and stability of the system. The performance of the proposed method was verified through simulations, multi-angle vibration experiments and comparative algorithm analysis. The experimental results show that this algorithm can accurately demodulate multi-dimensional signals under different tilt angles of vibration excitation. Particularly, after compensating for the triple interference information, the mean square error (MSE) of the demodulated acceleration decreased by 0.0044 g, and the accuracy increased by 70.9% compared to before correction. Full article

We demonstrate an all-polarization-maintaining (PM) mode-locked thulium-doped fiber laser operating in the net-normal-dispersion regime based on a figure-9 nonlinear amplifying loop mirror (NALM) configuration. A chirped fiber Bragg grating (CFBG) and a commercial PM dispersion-compensating fiber (PM-DCF) are incorporated into the figure-9 cavity, providing a large normal net dispersion and enabling stable dissipative-soliton mode-locking. Under stable dissipative-soliton operation, the laser delivers a maximum output power of 53.6 mW at a repetition rate of 12.31 MHz, corresponding to a pulse energy of 4.3 nJ. The output spectrum has a central wavelength of ~1952 nm with a 3 dB bandwidth of ~11 nm. The all-PM laser oscillator directly generates a fs pulse without extra-cavity compression, achieving a pulse duration of 545 fs at the CFBG arm. Moreover, stable fundamental mode-locking is verified by a high radio-frequency signal-to-noise ratio (SNR) exceeding 82 dB and a long-term root-mean-square (RMS) power fluctuation of 0.45% over two hours. To the best of our knowledge, this represents the highest output power generated from an all-PM-fiber figure-9 laser oscillator in the 2 μm band, alongside fs-pulse operation. This high-power, compact, stable and environment-insensitive fs-pulsed laser source shows great potential as an ideal seed for biomedical imaging and mid-infrared frequency combs. Full article

Background: Pediatric oral mucosal lesions are common and may indicate local or systemic disease, yet their recognition in primary healthcare often depends on non-dental professionals. Aim: To assess the preparedness of dentists, pediatricians, and family/general practitioners for pediatric oral mucosal conditions based on self-assessed diagnostic confidence, clinical management, and referral behavior. Methods: An online cross-sectional survey was conducted among 632 primary healthcare professionals (dentists: n = 262; family/general practitioners: n = 278; pediatricians: n = 92). The questionnaire assessed clinical exposure, self-assessed knowledge, diagnostic confidence, management practices, and referral patterns. Data were analyzed using chi-square or Fisher’s exact test and the Kruskal–Wallis test (p < 0.05). Results: Dentists reported significantly higher self-assessed knowledge and diagnostic confidence than pediatricians and family/general practitioners (p < 0.001). Good self-assessed knowledge of pediatric oral health was reported by 26.3% of dentists, compared with 7.9% of family/general practitioners and 6.5% of pediatricians. While most pediatricians (80.4%) and family/general practitioners (77.0%) reported routinely examining the oral cavity in children, independent treatment of oral mucosal lesions was more frequently reported by dentists (75.2%) than by pediatricians (52.2%) or family/general practitioners (70.9%) (p < 0.001). Referral patterns differed between groups, and willingness to attend future pediatric oral health education was high across all professionals (75.0–84.2%). Conclusions: Dentists demonstrated higher diagnostic confidence in pediatric oral mucosal lesions than pediatricians and family/general practitioners, who more often relied on referral. These findings support the value of targeted education and strengthened interdisciplinary collaboration in primary pediatric healthcare. Full article

Terahertz (THz) technology is finding increasingly widespread applications in biosensing, high-speed communication, and stealth materials. Meanwhile, graphene, as a quintessential two-dimensional material, has emerged as a core component of THz devices due to its unique optoelectronic properties. However, the precise and non-destructive characterization of the complex conductivity of graphene at the microscopic scale remains a formidable challenge. Conventional measurement methods often suffer from limitations associated with contact resistance or intricate sample preparation processes. In this paper, we propose a non-invasive parameter inversion method based on deep learning. We design a tri-layer graphene-silica-copper metasurface structure featuring a central cavity and establish a high-fidelity scattering model that incorporates physical effects such as edge diffraction and multi-mode resonance. Utilizing the Radar Cross Section (RCS) data generated by this model, we train a Deep Enhanced Conductivity Predictor (DECP) network integrated with a Convolutional Block Attention Module (CBAM). Experimental results demonstrate that the proposed network can accurately reconstruct the complex conductivity of graphene from far-field RCS data. The coefficients of determination (R²) for the prediction of both real and imaginary parts exceed 0.99, with a Root Mean Square Error (RMSE) as low as the order of 10⁻⁵. This study not only validates the effectiveness of data-driven approaches in material characterization but also provides a novel paradigm for the real-time monitoring and intelligent design of terahertz metasurfaces. Full article

Introduction: Extranodal extension (ENE) is a well-established adverse prognostic factor in head and neck squamous cell carcinoma (HNSCC), associated with reduced survival and the need for intensified therapy. Nutritional status—commonly assessed using the Prognostic Nutritional Index (PNI) and Body Mass Index (BMI)—also influences outcomes in HNSCC. However, whether or not ENE correlates with nutritional status has not been previously investigated. Methods: We conducted a retrospective cohort study of 109 treatment-naïve HNSCC patients with pathologically confirmed nodal metastases who underwent primary tumor resection and neck dissection between 2014 and 2025 at a national tertiary center. ENE status was determined histologically. Nutritional status was evaluated using BMI, PNI, serum albumin, and percentage of weight loss at diagnosis. Statistical analyses included t-tests, Chi-square tests, ANOVA, Cox regression, Kaplan–Meier survival analysis, and Full Factorial General Linear Models. Results: ENE was present in 54.1% of patients and significantly reduced overall survival (Kaplan–Meier p = 0.006; Cox regression RR = 1.927, p = 0.008). No significant differences in BMI, PNI, weight loss, or serum albumin were observed between ENE-positive and ENE-negative groups. ENE prevalence varied significantly by tumor origin (p = 0.018), being highest in hypopharyngeal cancers (75.8%) and lowest in oral cavity tumors (25.0%). ENE status was independent of tobacco use, alcohol abuse, and all nutritional markers across TNM 8/9 subgroups. Conclusions: ENE is a strong prognostic marker in HNSCC, appearing to be independent of nutritional status. The demonstrated heterogeneity of ENE prevalence among tumor subsites supports the need for individualized management approaches. Full article

Laparoscopic surgery provides minimally invasive access to the abdominal cavity but poses control challenges for robotic systems due to the fulcrum constraint at the abdominal wall and the simultaneous interaction of the instrument with both the abdominal wall and internal soft tissue. While current clinical platforms (e.g., da Vinci) primarily rely on visual feedback and do not possess force sensors at the instrument tip, the transition to autonomous robotic surgery requires precise force feedback to ensure safety and effective tissue manipulation. Therefore, developing methods to decouple interaction forces using a single force sensor configuration is a critical enabling technology for future instrumented surgical robots. This paper presents a force-decoupling method that estimates, using only one force sensor, the individual forces applied to the abdominal wall and to internal soft tissue through a viscoelastic modeling approach based on Maxwell elements. Two configurations were evaluated, showing that a single-element Maxwell model provides the best trade-off between accuracy and computational complexity, achieving estimation errors of 9% and 13% for abdominal wall forces, with a root mean square error (RMSE) below 0.36 N. The method was implemented and experimentally validated in a force-controlled robotic system, demonstrating its effectiveness in improving force regulation and interaction safety without requiring additional sensors. Full article

Direct methods provide a model-free approach to solving the crystallographic phase problem and deliver unbiased atomic structures. However, conventional iterative projection algorithms such as Hybrid Input–Output (HIO) face two critical challenges: discontinuous density modification at the protein-solvent boundary and inaccurate molecular envelope reconstruction that fails to account for trapped solvent, particularly in crystals with solvent content approaching the lower limits of direct phasing applicability. We introduced four continuous iterative projection algorithms, including our improved continuous version, which implements smooth density modification at protein-solvent interfaces. To address envelope inaccuracy, we developed a two-step refined reconstruction scheme using sequential large-radius and small-radius Gaussian filters to identify trapped solvent molecules within surface cavities and internal channels. This scheme enhances the performance of both continuous and classical algorithms, including HIO, the difference map, and our improved versions. Benchmarking on 28 protein structures (solvent contents 55–78%, resolutions 1.46–3.2 Å, reported R-factor less than 0.22) showed that the refined envelope scheme increased average success rates of continuous algorithms by 45.7% and classical algorithms by 60.5%. The performance of continuous algorithms and improved classical algorithms proved comparable to the well-established HIO algorithm, forming a top-tier group that exceeded other classical algorithms. Integrating a genetic algorithm co-evolution strategy further enhanced average success rates by approximately 2.5-fold and accelerated convergence through population-wide information sharing. Although the success rate correlates with solvent content, our strategy improved success probability at any given solvent level, extending the practical boundaries of direct methods. The high success rate enabled averaging of multiple independent solutions, which reduced mean phase error by approximately 6.83° and yielded atomic models with backbone root-mean-square deviation (RMSD) typically below 0.5 Å relative to structures reported in the Protein Data Bank (PDB). This work introduces novel algorithms, a refined envelope reconstruction methodology, and an effective optimization strategy with genetic algorithm evolution. The complete framework enhances the capability and reliability of direct methods for phasing protein crystals with limited solvent content and provides a toolkit for addressing challenging cases in structural biology. Full article

Background/Objectives: Oral health-related quality of life (OHRQoL) is a complex topic, encompassing the medical, functional and psychosocial aspects of well-being, especially in the context of systemic conditions that can trigger oral cavity impairment. While this subject has been extensively investigated in adults, evidence remains limited in pediatric populations, particularly in children with leukemia who are at high risk for oral complications related to the disease itself and its treatment. Moreover, children and parent perceptions of oral health are essential for guiding preventive and personalized therapeutic strategies, yet they are poorly explored in this clinical context. The objective of this study was to assess OHRQoL in children with leukemia and gingival inflammation, and compare it with that of children without this systemic condition. Methods: This observational, cross-sectional, case–control study was conducted on 99 subjects, divided into two groups: the study group n = 49 leukemia subjects and the control group n = 50 subjects without oncologic pathology. Clinical examination of all subjects was performed and oral health status was evaluated using Oral Health Index-Simplified (OHI-S) and Gingival Index (GI). Parents filled out a personalized exploratory questionnaire, adapted after established scales, designed to capture the child’s perceived impact of certain leukemia-related gingivo-periodontal alterations, including pain, ulcerations, gingival bleeding and xerostomia. Data were analyzed using descriptive statistics, Pearson’s Chi-square test and comparative graphical analyses (IBM SPSS Statistics 26). Results: Children with leukemia reported higher frequencies of xerostomia, ulcerations and gingival bleeding compared to children in the control group, with xerostomia showing a suggestive association to gingival inflammation. Oral hygiene status of children in the leukemia group was generally better among children receiving parental assistance during brushing or those practicing dental flossing. Comparative graphical analyses showed differences in symptom reporting and oral hygiene support between groups. Conclusions: The results suggest that xerostomia seemed to align with gingival inflammation in children with leukemia, while parental assistance and dental flossing seemed to be associated with better oral hygiene status. Our findings also support the need for developing standardized, disease-oriented scales of evaluating OHRQoL, as well as individualized oral care and continuous monitoring in order to improve oral health-related quality of life in this vulnerable pediatric population. Full article

Modular construction refers to the use of factory prefabricated integrated module units. The modular steel construction unit SHS (Square Hollow Section) group column is a structure composed of four independent steel column units. Due to its compositional characteristics with voids, the fire resistance performance differs from ordinary steel columns, necessitating specific study. This paper employed a sequentially coupled thermal–mechanical analysis to investigate this. The effectiveness of the simulation model was first validated by comparing the simulated time–temperature curves and fire resistance limits with experimental results. A parametric analysis was then conducted to evaluate the influence of various factors, including the load ratio, cavity spacing, insulation type, gypsum board thickness, slenderness ratio, steel yield strength, and inner panel type, on the fire resistance limit. The results show that when the gypsum board thickness increased from 10 mm to 30 mm, the fire resistance limit correspondingly increased by 126%, 120%, 130%, and 130% for load ratios of 0.4, 0.5, 0.6, and 0.7, respectively. When the steel yield strength increased from 235 MPa to 690 MPa, the fire resistance limit increased by 20%, 21%, 24%, and 43% for load ratios ranging from 0.4 to 0.7. For inner panels of Glass Fiber, Rock Wool, Mineral Wool, and Plasterboard, the corresponding fire resistance limit ratios for load ratios of 0.4 to 0.7 were 1:1.13:1.24:1.45, 1:1.14:1.23:1.46, 1:1.11:1.2:1.42, and 1:1.08:1.18:1.41, respectively. It can be found that the best way to increase the fire resistance of the modular column is to increase the thickness of the gypsum board. A simplified calculation formula for the fire resistance limit of SHS group columns was derived through regression analysis, and recommendations for fire protection design were proposed, providing valuable insights for the future design and application of SHS group columns in steel modular construction. Full article

A comprehensive numerical analysis has been conducted to investigate unsteady natural convection (UNC), bifurcation behavior, and heat transfer (HT) in a rectangular enclosure containing thermally stratified air. The enclosure comprises a uniformly heated bottom wall, thermally stratified vertical sidewalls, and a cooled top wall. To assess thermal performance, square and rectangular cavities with identical boundary conditions and working fluid are considered. The finite volume method (FVM) is used to solve the governing equations over a wide range of Rayleigh numbers (Ra = 10¹ to 10⁹) for air with a Prandtl number (Pr) of 0.71. Flow dynamics and thermal performance are analyzed using temperature time series (TTS), limit point–limit cycle behavior, average Nusselt number (Nu_avg), average entropy generation (S_avg), average Bejan number (Be_avg), and the ecological coefficient of performance (ECOP). In the rectangular cavity, the transition from steady to chaotic flow exhibits three bifurcations: a pitchfork bifurcation at Ra = 3 × 10⁴–4 × 10⁴, a Hopf bifurcation at Ra = 3 × 10⁶–4 × 10⁶, and the onset of chaotic flow at Ra = 9 × 10⁷–2 × 10⁸. The comparative analysis indicates that Nu_avg remains nearly identical for both cavities within Ra = 10⁵ to 10⁷. However, at Ra = 10⁸, the HT rate in the rectangular cavity is 29.84% higher than that of the square cavity, while S_avg and Be_avg differ by 39.32% and 37.50%, respectively. Despite higher HT and S_avg in the rectangular enclosure, the square cavity demonstrates superior overall thermal performance by 13.52% at Ra = 10⁸. These results offer significant insights for optimizing cavity geometries in thermal system design based on energy efficiency and entropy considerations. Full article

This paper presents a 2D micro-conveyance device based on a 3 × 3 electromagnetic digital actuator array. This device allows the conveyed object to be moved between several discrete positions distributed in the xy-plane through a collaborative actuation of the digital actuators. Each digital actuator includes a mobile permanent magnet placed in a square cavity and can be moved between four discrete positions. An analytical model of the digital actuators was proposed and used to design the conveyance device. Then, a prototype was built using rapid prototyping techniques and was experimentally characterized. The reachable workspace of the conveyance device is 56 mm × 56 mm in the xy-plane, and the proposed architecture enables the workspace to be easily enlarged by adding elementary modules. The distance between two discrete positions is 4 mm, and the positioning repeatability was measured as 5.5 µm. The maximum conveyance velocity and transportable mass were found to be up to 16 mm.s⁻¹ and 15 g, respectively. Full article