Search Results (670)

Ultraviolet sensitivity in birds is generally attributed to short-wavelength-sensitive type 1 single cones, but ultraviolet radiation may influence the retina through several additional pathways. We reviewed molecular, optical, physiological, and behavioral evidence for canonical and putative noncanonical ultraviolet detection in the avian retina. Under photopic conditions, short-wavelength-sensitive type 1 cones provide an established chromatic pathway, whereas secondary ultraviolet absorption bands of other cone pigments may contribute at high irradiance. Under scotopic conditions, particularly in rod-dominated owls lacking functional ultraviolet- or violet-sensitive type 1 cones, the secondary ultraviolet absorption band of rhodopsin provides a plausible achromatic pathway. Ultraviolet-sensitive opsin 5 in inner-retinal neurons and Müller glia may mediate local regulatory or non-image-forming responses. We also examine fluorescence of oil droplets in double cones as a possible route into the luminance system. Previous reports described ultraviolet-induced visible fluorescence in chicken retinal oil droplets and fluorescence of chicken double-cone droplets under blue excitation, although physiological activation of the adjacent visual pigment by droplet fluorescence has not been established. These mechanisms are not mutually exclusive, and their relative contributions probably depend on irradiance, adaptation state, ocular-media transmission, receptor abundance, and behavioral context. Receptor-specific physiological and behavioral experiments are required to distinguish between them. Full article

Background and Objectives: Residual filling material may persist on the walls of oval root canals after mechanical retreatment, and the influence of sodium hypochlorite (NaOCl) concentration and supplementary irrigation procedures on its removal remains unclear. This laboratory study used scanning electron microscopy (SEM) to evaluate the effects of three NaOCl concentrations and five final irrigation protocols on residual filling material in retreated oval canals of mandibular premolars. The protocols tested were conventional needle irrigation (CNI), EDDY, passive ultrasonic irrigation (PUI), XP-endo Finisher R (XPFR), and Shock Wave Enhanced Emission Photoacoustic Streaming (SWEEPS). Materials and Methods: One hundred twenty extracted mandibular premolars with a single root and an oval canal were instrumented with Reciproc R25 and filled with CeraSeal and a matching gutta-percha cone using the single-cone technique. Root canal retreatment was performed using ProTaper Universal Retreatment instruments followed by Reciproc R40. The teeth were then distributed among 15 experimental subgroups according to the final irrigation protocol and NaOCl concentration used: 2.5%, 5.25%, or 8.25% (n = 8). After irrigation, each root was divided longitudinally, and one undamaged canal half was randomly chosen for SEM evaluation. Residual filling material was scored in the coronal, middle, and apical regions using an ordinal scale ranging from 1 to 5. Examiner agreement was determined with quadratically weighted Cohen’s kappa, while treatment effects were examined using a cumulative link mixed model (CLMM). Results: Residual filling material scores differed significantly according to the final irrigation protocol (p < 0.001) and root canal region (p = 0.007), but not according to NaOCl concentration (p = 0.236). The interaction between protocol and canal region was also significant (p = 0.036). In the overall comparisons, CNI produced the highest scores, whereas SWEEPS produced the lowest, and EDDY, PUI, and XPFR did not differ significantly from one another. Apical scores were higher than coronal and middle scores in the EDDY, PUI, and SWEEPS protocols, while XPFR showed no significant variation among canal regions. Conclusions: Residual filling material scores after retreatment were influenced by the final irrigation protocol and root canal region, whereas NaOCl concentration had no significant main effect. SWEEPS resulted in the lowest overall residual filling material scores and CNI in the highest, while EDDY, PUI, and XPFR showed comparable overall performance, although protocol performance varied across root canal regions. Full article

Tooth-bearing structures are commonly involved in the spread of various odontogenic lesions. Radicular and dentigerous cysts are among the most common odontogenic cysts, exhibiting significant variations in size and morphology within the jawbones. On the other hand, the influence of dental caries, periodontal diseases, and periapical lesions extends beyond tooth-bearing bone and also affects adjacent anatomical structures, especially the maxillary sinuses. In addition to untreated odontogenic lesions, treatment-related complications in the posterior maxilla may also disturb the sinus environment, particularly when oroantral communication is not recognized or adequately managed. The etiology of sinusitis is multifactorial; however, tooth-related infections are the primary cause of odontogenic sinusitis (ODS). Routine upper posterior tooth extraction may also become clinically significant when pre-existing sinus mucosal changes, close sinus floor proximity, or persistent oroantral communication are overlooked. When ODS is undiagnosed or overlooked on a classic computed tomography or a cone beam computed tomography (CBCT) scan, it is frequently inadequately managed by otolaryngological interventions alone; this leaves the underlying dental pathology unaddressed. Consequently, the utilization of CT/CBCT and close collaboration between dentists, oral surgeons, and otolaryngologists are essential for the successful management of these conditions. In advanced cases of ODS, isolated intranasal otolaryngological procedures are often insufficient. Comprehensive management relies on the elimination of all sources of odontogenic infection through endodontic therapy, dental extractions, and localized bone curettage. While the traditional Caldwell–Luc approach (CLA) is not commonly used nowadays, it remains an important surgical option in select cases, especially when infection spreads beyond tooth-bearing structures or soft tissue abscesses are present. This paper presents the radiological and clinical findings of two ODS cases with different etiologies and demonstrates how these findings influenced surgical planning. The aim is not to introduce the Caldwell–Luc approach as a novel technique but to illustrate its selective role when the direct treatment of the odontogenic source and oroantral defect is required. Full article

Background: Infrazygomatic crest (IZC) miniscrews provide reliable extra-alveolar skeletal anchorage for orthodontic tooth movement while minimizing dependence on patient compliance. Although guided insertion techniques have been proposed to improve placement accuracy, freehand insertion remains widely used because of its simplicity and clinical practicality. This retrospective study evaluated the clinical performance and survival of freehand-placed IZC miniscrews over a minimum follow-up period of 30 months. Materials and Methods: A retrospective observational study was conducted on 23 consecutive patients receiving a total of 30 IZC miniscrews between January 2022 and July 2024. All miniscrews were placed freehand by the same experienced orthodontist following individualized radiographic planning based on panoramic radiography and/or cone-beam computed tomography (CBCT), according to the patient’s anatomical requirements. Miniscrews were immediately loaded using light orthodontic forces (<100 g), with progressive force increases during subsequent appointments based on treatment objectives. Patients were reviewed at approximately 30–35-day intervals. Clinical records were analyzed to assess miniscrew survival, timing of failure, and procedure-related complications using descriptive statistical analysis. Results: Twenty-seven of the 30 miniscrews remained clinically stable throughout treatment, corresponding to an overall success rate of 90.0%. Three failures occurred during the early treatment phase, while no late failures were observed. Because of the limited number of failure events, potential contributing factors—including screw dimensions, mechanical interference, and deterioration of oral hygiene during treatment—were evaluated descriptively and should be interpreted with caution. No major surgical or radiographic complications were detected during follow-up. Conclusions: Within the limitations of this retrospective observational study, freehand placement of IZC miniscrews demonstrated favorable clinical performance when performed by an experienced operator following appropriate radiographic planning. However, the relatively small sample size, absence of a control group, and descriptive nature of the analysis preclude definitive conclusions regarding factors influencing miniscrew failure or the comparative effectiveness of freehand versus guided insertion. Larger prospective controlled studies are warranted to validate these preliminary findings. Clinical relevance Manual IZC miniscrew insertion represents a predictable, efficient, and cost-effective alternative to guided approaches in orthodontic practice. Full article

As a widely used encapsulant for power electronic devices, silicone gel is continuously exposed to high voltage and high temperature during service, which seriously impairs the reliability and service lifetime of power modules. This work investigates the electrothermal coupling failure mechanism of conventional silicone gel under high-voltage and high-temperature environments; the influences of different pulse electric field edge times and aging stages on various properties of the material are investigated, including electrical treeing characteristics, breakdown field strength, amplitude of charge-excited molecular vibration, leakage current, and cone penetration. It is revealed that the failure mechanism of silicone gel is attributed to the synergistic effect between dynamic charge damage induced by the pulse edge electric field and the degradation of the solid–liquid two-phase structure at high temperatures. This research provides theoretical support and experimental basis for material composition modification, structural optimization, and improving the encapsulation life of power electronic devices. Full article

Micro-Newton cold-gas thrusters are promising actuators for precision space missions, but their performance is strongly influenced by the integrated head architecture. This study presents the design, fabrication, and experimental validation of a piezoelectrically controlled cold-gas microthruster head for space-based gravitational-wave detection missions. The proposed head integrates a cone-needle throttle, a micro-orifice interface, and a downstream micro-nozzle, thereby converting actuator displacement into a regulated mass flow and ultimately into thrust. One-dimensional theory was first used for preliminary sizing, and Direct Simulation Monte Carlo (DSMC) analysis of the complete throttle-nozzle geometry was then applied to determine the final design parameters under rarefied-flow conditions. The selected design uses a throat radius of 29 μm and a needle half-angle of 10 degrees. Following fabrication and structural characterization, the integrated device was validated through mass-flow calibration and vacuum thrust testing. The experimental results show that the pressure-decay-based calibration provides a consistent mapping between actuation command, calibrated flow rate, and thrust output. The measured flow–thrust relation preserves the high linearity predicted by simulation, while the experimentally evaluated specific impulse meets the specified design target over the tested range. In addition, thrust-resolution testing at a baseline thrust of approximately 98.4 micro-Newton demonstrates a minimum resolvable step of 50 nano-Newton, and the measured thrust-noise amplitude spectral density remains below 0.07 micro-Newton/sqrt(Hz) over the 10 mHz–1 Hz band for the tested thrust levels. These results support the feasibility of the proposed integrated cold-gas microthruster head and its device-level validation approach for future space-based gravitational-wave detection applications. Full article

Triply periodic minimal surfaces (TPMSs) are increasingly used in thermal management systems due to their high surface area and interconnected porous architecture. However, how TPMS geometry influences fire growth remains poorly understood. Herein, Gyroid, Diamond, and Schwarz-P PLA structures were fabricated through additive manufacturing, and their fire behavior was characterized via cone calorimetry. Univariate experiments demonstrate that flame propagation is primarily governed by cell structure, rather than porosity or specific surface area. The orthogonal array L₉(3³), covering three factors of wall thickness, cell size and cell type (Gyroid, Diamond, and Schwarz-P), indicates that their effects on the flame growth index (FGI) rank as: cell size > unit cell > thickness. Meanwhile, a multivariate regression model was developed to predict the FGI of TPMS porous PLA, exhibiting high prediction accuracy (R² = 0.95) and low residual standard deviation. These results provide quantitative insights into the correlation between TPMS geometric features and fire growth, which facilitates the design of safer porous structures for thermal management applications. Full article

This study investigates marine sand collected from the southeastern coast of China through laboratory calibration chamber model tests under varying relative densities and consolidation stresses. The consolidation characteristics and cone penetration test (CPT) penetration response of soil specimens were examined, and interpretation models relating CPT parameters to soil unit weight, relative density, and shear wave velocity were established. Results show that shear wave velocity increases with relative density, with consolidation exerting a stronger enhancement. Lateral earth pressure exhibits a pronounced distance attenuation effect, with stress differences most prominent near-field and diminishing with distance. Cone tip resistance increases with both relative density and consolidation stress, with consolidation stress exerting a more significant influence on low-density specimens; sleeve friction increases linearly with relative density. The interpretation models achieve good correlations with unit weight (R² = 0.78), normalized cone tip resistance with the square of relative density (R² = 0.72), and shear wave velocity (R² = 0.85), and field validation confirms higher prediction accuracy than conventional empirical formulas for terrigenous sands. The models enable rapid, cost-effective parameter estimation from routine CPT data, though they remain site-specific, being based on nine chamber tests and validated against six field layers from a single site. Full article

This paper introduces a temperature-based design method for determining the tensile concrete cone capacity of anchors subjected to fire exposure. Current prescriptive approaches, most notably Eurocode 2, rely solely on embedment depth and fire duration for fire exposure from one or more directions on one concrete face with and without edge effects. The purpose of this work is to develop a temperature-based design method for predicting tensile concrete cone failure of anchors under fire conditions. Through an experimental program, this study demonstrates that anchor capacity can be conservatively described by temperature associated with embedment depth. A parametric analysis on the influence of concrete strength, anchor group effect, edge effect, concrete cracking, anchor type and heating orientation on different concrete faces defines the scope of application of the design method. The proposed method incorporates measured temperature profiles, offering a more precise alternative to the existing design method in Eurocode 2 and enabling flexible design for different structural configurations and fire scenarios. Optimized design is enabled in comparison to the existing prescriptive method (EN 1992-4) exclusively based on embedment depth and fire duration. Research findings demonstrate that anchor capacity correlates strongly with the temperature at the effective embedment depth under varying conditions. Full article

This study develops a mathematical model for non-Darcian flow toward a fully penetrating pumping well in a confined aquifer, explicitly incorporating both well skin effects and non-Darcian flow behavior, which are conventionally neglected in classical models. A two-zone radial flow model consisting of a skin zone and a background region is established to account for hydraulic property differences caused by well construction. The Izbash equation is adopted to describe the nonlinear velocity-gradient relationship, and the transformed differential quadrature method (TDQM) is employed for the efficient solution. By combining the Laplace transform, differential quadrature discretization, and Stehfest numerical inversion, transient drawdown responses are obtained. The model is verified against benchmark solutions and field pumping-test data, showing good agreement. Parametric analyses reveal that (1) increasing the non-Darcian parameter intensifies near-well flow resistance, producing a steeper and more localized drawdown cone; (2) a larger skin factor (improved near-well hydraulic conductivity) significantly reduces drawdown and enhances well efficiency; and (3) increasing skin thickness primarily improves near-field hydraulic response with limited far-field influence. The proposed framework provides an effective tool for analyzing nonlinear pumping behavior in radially heterogeneous aquifers. Full article

Upstream–downstream nutrient connectivity strongly regulates water-quality risk in reservoir cascades, yet its quantification remains difficult where discharge, reservoir release, and hydraulic residence-time records are unavailable. This study developed a causal–explainable framework to diagnose total nitrogen (TN) connectivity between the upstream Shimantan Reservoir and downstream Banqiao Reservoir in the Huai River Basin, China. Long-term water-quality records, meteorological variables, land-cover indicators, seasonal descriptors, and lagged upstream predictors were integrated within a leakage-safe analytical workflow combining nonlinear causal inference, time–frequency coupling diagnostics, predictive modeling, SHAP-based attribution, and counterfactual analysis. Convergent Cross Mapping identified statistically significant asymmetric bidirectional nonlinear coupling, with a CCM skill of ρ = 0.746 for Shimantan TN → Banqiao TN and p = 0.730 for the reverse direction (p = 0.002 for both directions). Wavelet coherence showed that upstream–downstream TN coupling was concentrated mainly at short temporal scales, with a cone-of-influence-restricted mean squared coherence of 0.7114 in the 2–6-month intra-seasonal band. The validation-selected Gradient Boosting model provided interpretable test-period predictive skill, on independent source-derived observations from 2021–2023, achieving R² = 0.567, RMSE = 0.391 mg/L, and MAE = 0.312 mg/L. The GAN-generated 2024–2025 segment was excluded from empirical model evaluation and retained only for exploratory future-scenario assessment. SHAP decomposition indicated that upstream-related predictors accounted for 77.04% of the total absolute model attribution during high-TN events, while seasonal conditioned counterfactual upstream neutralization produced mean model-predicted changes of 0.162 mg/L across all test observations and 0.807 mg/L during high-TN events. Together, these results demonstrate that hidden upstream-downstream TN connectivity can be diagnosed through convergent causal, temporal, predictive, and model-attribution evidence in data-limited reservoir cascades. The findings support asymmetric coupled dynamics and downstream inheritance of upstream information but should not be interpreted as proof of exclusively one-way physical nutrient transport. The proposed framework offers a diagnostic decision-support approach for reservoir systems with sufficiently long monitoring records where direct hydraulic observations are unavailable. Full article

Bioceramic sealers have gained widespread acceptance in contemporary endodontics due to their favorable biological properties, dimensional stability, and bioactivity. However, their strong adhesion to dentinal walls and penetration into dentinal tubules may complicate removal during endodontic retreatment procedures. Additionally, the obturation technique may influence both the retreatability of root canal filling materials and the bond strength of sealers and resins to radicular dentin. Methods: One hundred extracted human single-rooted teeth were instrumented using the WaveOne Gold system and obturated with a bioceramic sealer using two techniques: single-cone (Group A, n = 50) and warm vertical compaction (Group B, n = 50). After sealer setting, retreatment procedures were performed using ProTaper Universal Retreatment files combined with passive ultrasonic irrigation. Scanning electron microscopy was used to evaluate smear layer removal and dentinal tubule obstruction. Eighty specimens were subsequently re-obturated with a bioceramic sealer and divided into four subgroups according to the obturation technique used before and after retreatment. A push-out bond strength test was performed on coronal, middle, and apical root sections. Statistical analysis was conducted using SPSS software with a significance level set at p ≤ 0.05. Results: No statistically significant differences were observed between the groups regarding the working time required for root filling removal (p > 0.05). However, significant differences were found in push-out bond strength values among the experimental groups (p < 0.05). Specimens obturated using warm vertical compaction showed significantly higher bond strength compared with the single-cone technique. Scanning electron microscopy observations revealed less residual bioceramic sealer on dentinal walls in the warm vertical compaction group. Conclusions: Within the limitations of this in vitro study, the warm vertical compaction technique demonstrated superior bonding performance and resulted in less residual bioceramic sealer after retreatment compared with the single-cone technique. Full article

Background/Objectives: Obstructive sleep apnea (OSA) is highly prevalent in children with unilateral cleft lip and palate (UCLP) due to maxillary retrusion and upper airway compromise. While palatal morphology may influence pediatric OSA, three-dimensional (3D) evaluations in this population remain limited. This study evaluated palatal dimensions and maxillary widths in UCLP children with and without OSA using cone-beam computed tomography (CBCT) and examined their associations with OSA severity (apnea–hypopnea index, AHI). Methods: Forty CBCT scans of Thai children with non-syndromic UCLP (mean age 8.98 ± 1.99 years) were analyzed. Participants were categorized into OSA (n = 20; AHI ≥ 1) and non-OSA (n = 20; AHI < 1) groups. Reconstructed palatal structures were measured for surface area, volume, height, and transverse maxillary widths. Group differences were assessed using independent t-tests, and associations with AHI were examined via Pearson’s correlation and linear regression (p < 0.05). Results: Children with OSA exhibited significantly reduced palatal surface area, volume, height, and buccal alveolar crest width compared with those without OSA (p < 0.05). Other transverse widths showed no significant intergroup differences. Linear regression identified palatal volume as the only variable independently associated with AHI (β = −0.631, p < 0.001). Conclusions: Children with UCLP and OSA exhibit significantly constricted palatal morphology. Among the measured parameters, reduced three-dimensional palatal volume was the only variable independently associated with increased OSA severity in this sample. Thus, CBCT-based palatal volume assessment may serve as a preliminary screening parameter to help identify OSA risk within multidisciplinary cleft care, though further validation is needed. Full article

Hydraulic nozzles are widely utilized for dust removal, cooling, and waste heat recovery in mining production. Nevertheless, the influence of co-flow disturbance on the atomization characteristics within the downstream region of droplet fields remains inadequately understood. In this study, three typical hydraulic nozzles were selected, and the atomization characteristics of the downstream region under different co-flow disturbance intensities were experimentally investigated. The results reveal that increasing co-flow disturbance velocity does not intensify the reduction in sauter mean diameter (SMD), but markedly reduces the dispersed phase fraction (DPF). Under four co-flow disturbance velocities (1.5, 3.0, 4.5, and 6.0 m/s), the relative reduction rates of mean SMD are 6.77%, 3.27%, 4.42% and 2.60%, while those of mean DPF are 13.86%, 35.85%, 52.88%, and 61.86% (e.g., hollow-cone nozzle), respectively. The variation in SMD is achieved through the redistribution of cumulative volume among CV₁, CV₂, CV₃, and CV₄. As the velocity increases from 0 to 3 m/s, the mean SMD of the three hydraulic nozzles exhibits a decreasing trend, which can be directly attributed to the continuous increase in the total cumulative volume of CV₁ and CV₂, and the continuous decrease in those of CV₃ and CV₄. For the hollow-cone and solid square-cone nozzles, the SMD first decreases and then increases, with the turning point occurring at 3.0 m/s, consistent with the variation trend of cumulative volume fractions. In contrast, for the solid-cone nozzle, the SMD continues to decrease at velocities exceeding 3.0 m/s. This work provides both a fundamental understanding of atomization characteristics in the downstream region of hydraulic nozzles under co-flow disturbance and practical guidance for velocity control in mine spray systems. Full article

Background: Impacted maxillary canines frequently cause external root resorption of adjacent lateral incisors, a complication that may compromise tooth survival and orthodontic outcomes. Cone-beam computed tomography (CBCT) enables precise three-dimensional assessment of canine position and resorption severity, yet the quantitative relationship between canine angulation and resorption remains incompletely characterized. Objectives: The objectives were to quantify the correlation between impacted maxillary canine angulation relative to the vertical reference line and the severity of adjacent lateral incisor root resorption using CBCT and to evaluate the influence of crown position on resorption prevalence. Materials and Methods: This retrospective cross-sectional study was conducted at the Department of Oral Radiology, King Abdulaziz University Dental Hospital (KAUDH), Jeddah, Saudi Arabia, using CBCT scans acquired between January 2018 and December 2023. CBCT scans of 262 patients with impacted maxillary canines were analyzed. A total of 108 impacted canines from 88 patients were evaluated. Canine angulation was measured as the acute angle between the canine long axis and a vertical reference line on coronal CBCT sections. Crown position was classified as palatal, buccal, or center. Lateral incisor root resorption was graded using the modified Kaley and Phillips classification (Grade 0–4), where Grade 4 represents side resorption. Statistical analyses included Spearman rank correlation, Mann–Whitney U test, chi-square test, and Kruskal–Wallis test with post hoc comparisons (α = 0.05). Results: Lateral incisor root resorption was detected in 17 of 108 canines (15.7%). Mean canine angulation was significantly higher in the resorption group (45.5° ± 21.4°) compared with the no-resorption group (32.7° ± 18.0°; Mann–Whitney U = 809.5, p = 0.019). Spearman correlation revealed a significant positive association between angulation and resorption grade (ρ = +0.243, p = 0.019). Canines angled ≥ 45° exhibited a 3.5-fold higher resorption rate (32.1% vs. 9.2%; OR = 4.66, Fisher’s Exact p = 0.012). Palatal crown position was associated with significantly higher resorption prevalence (25.5%) compared with center (5.1%) and buccal (11.1%) positions (χ² = 7.258, p = 0.027). Unilateral impaction was associated with significantly higher resorption prevalence than bilateral (22.4% vs. 4.9%; p = 0.031). Conclusions: Larger canine angulation from the vertical reference line is significantly correlated with increased severity of adjacent lateral incisor root resorption. Palatal crown position, angulation ≥ 45°, and unilateral impaction pattern are important risk indicators. CBCT-based angulation measurement provides clinically relevant quantitative data to inform early intervention and treatment planning. Full article