Search Results (1,298)

Background: The pterygoid plates serve as crucial reference points for posterior maxillary surgery and the placement of pterygoid implants; however, population-specific morphometric reference values remain underexplored for adults of Asir region (Abha city) of Saudi Arabia. Methods: This retrospective cross-sectional cone beam computed tomography (CBCT) study analyzed the archived scans obtained at King Khalid University Dental Hospital. Of 100 randomly selected adult CBCT scans collected between June and October 2025, 50 images met the eligibility criteria. The analyses were conducted using OnDemand3D software to measure the bilateral pterygoid plates’ length, thickness at the maximum diameter, and medial-lateral divergence angle. Styloid process length was measured as an exploratory variable. Three calibrated examiners performed the measurements, and the reliability was assessed using interclass correlation coefficients. Results: Fifty CBCT scans met the inclusion criteria (30 males, 20 females). The mean lateral pterygoid plate length was 14.61 ± 3.69 mm on the right and 13.83 ± 3.93 mm on the left, while the mean medial plate length was 11.27 ± 3.52 mm (right) and 11.98 ± 3.82 mm (left). Side to side paired comparisons showed no significant right–left differences in lateral plate length (mean R–L 0.79 mm, 95% CI −0.48 to 2.06), lateral thickness (mean 0.04 mm, 95% CI −0.14 to 0.22), medial thickness (mean 0.01 mm, 95% CI −0.19 to 0.21), or pterygoid angulation (mean 1.99°, 95% CI −1.07 to 5.05), supporting bilateral symmetry. Bilateral correlations were strong for medial plate length (r = 0.729, p < 0.001) and angulation (r = 0.632, p < 0.001). Males had a longer right lateral plate than females (15.74 ± 3.55 mm vs. 12.93 ± 3.31 mm; mean difference 2.81 mm, 95% CI 0.80–4.82; p = 0.007), whereas other measurements did not differ by sex. Plate thickness ranged from approximately 1.33 to 1.46 mm and left medial plate thickness correlated negatively with left medial plate length (r = −0.399, p = 0.004). Styloid process length averaged 22.99 ± 9.76 mm and showed no significant association with pterygoid plate measures. Conclusions: CBCT-derived findings demonstrated overall bilateral symmetry and limited dimorphism in relation to sex. These region-specific morphometries support individualized preoperative posterior maxillary surgery and pterygoid implant planning. Full article

Bipolar plates are critical components in high-efficiency energy conversion devices such as electrolyzers, fuel cells, and flow batteries, and their durability directly affects the overall performance and lifespan of the system. Although graphite bipolar plates exhibit excellent electrical conductivity and corrosion resistance, their inherent brittleness and porous structure render them prone to thermal-stress-induced damage under dynamic temperature conditions. In this study, a self-designed thermal shock testing system was utilized to perform 16,000 cycles of accelerated aging tests on graphite bipolar plates, alternating between high-temperature (90 °C) and low-temperature (30 °C) water bath environments. Systematic analysis was conducted on the performance degradation behaviors under such thermal cycling conditions using multi-scale characterization techniques, including scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), electrical conductivity, contact angle, surface roughness, and corrosion current density analysis. The results demonstrate that the degradation in electrical conductivity, loss of hydrophobicity, and increased surface roughness were primarily attributed to thermal-stress-induced microcrack initiation and propagation, surface oxidation, and physical structural deterioration. Notably, the corrosion current density did not increase significantly after 16,000 thermal cycles, but slightly decreased in the later stage, indicating that the aging of graphite bipolar plates is dominated by physical fatigue damage, and the graphite matrix has excellent chemical stability. The novelty of this study lies in the construction of a thermal shock testing system under long-cycle conditions, revealing the synergistic mechanism of thermal cycle-induced performance degradation of graphite bipolar plates, which provides experimental evidence and theoretical guidance for the material selection, structural design, and protection strategies of highly durable bipolar plates. Full article

Y-branched TiO₂ nanotubes (NTs) were produced by anodizing titanium plates derived from aerospace production leftovers and subsequently engineered to develop an enhanced TiO₂-based photocatalytic system. The NTs were electrochemically reduced to obtain reduced TiO₂ nanotubes (rTN) with a narrowed bandgap, followed by surface modification with polydopamine (PD) and silk fibroin-derived quantum dots (QDs) to promote enhanced UV and visible-light photocatalysis for wastewater treatment. The QDs were hydrothermally synthesized from Bombyx mori silk fibroin. Scanning Electron Microscopy (SEM) revealed spherical QD agglomerates encapsulated within the PD layer, while Energy Dispersive X-ray Spectroscopy (EDX) confirmed the presence of carbon and nitrogen originating from both PD and QD. The resulting rNT/PD/QD photocatalyst exhibited a significantly reduced bandgap (1.03 eV), increased Urbach energy (1.35 eV), and moderate hydrophilicity. A high double-layer capacitance (C_dl) indicated an enlarged electrochemically active surface due to the combination of treatments. Electrochemical characterization demonstrated reduced electrical resistance, higher charge density, and lower electron–hole recombination, leading to improved interfacial charge transfer efficiency and electrochemical stability during multi-cycle cyclic voltammetry measurements. Preliminary photocatalytic tests show that the rNT/PD/QD photocatalyst achieved a degradation efficiency of 79.26% for methyl orange (MO) and 35% for tetracycline (TC). Full article

Elemental arsenic (As) is essential for diverse industrial applications. Most elemental As in China is produced by reducing gaseous arsenic trioxide (As₂O₃) with carbonaceous materials in steel reactors. This study aimed to extend the reactor lifespan through corrosion experiments and analysis. In this study, corroded regions of steel reactors were inspected after each production batch, and the corrosion process was examined. X-ray diffraction (XRD) was used to identify the major corrosion products, X-ray fluorescence (XRF) was used to measure the composition of corroded area, scanning electron microscopy (SEM) and energy-dispersive spectroscopy (EDS) were used to inspect the features and elemental distributions of the corroded steel-plate cross-sections. The results revealed that the steel wall near the charcoal zone exhibited the highest corrosion rate. Tin (Sn), selenium (Se), and antimony (Sb) did not promote the corrosion process, whereas carbon (C) accelerated it by forming an Fe–As–C system at the grain boundaries of the steel matrix, characterized by a low melting temperature. The important source of C responsible for initiating corrosion was solid-state C particles originating from reused materials from previous batches. Additionally, owing to the high processing temperature, oxygen (O) was transferred to the inner side of the steel wall before the dramatical corrosion of the matrix by elemental As and C. Results of this study provide references to increase the lifespan of steel reactors for elemental As production. Full article

To evaluate the influence of different surface conditioning protocols—sandblasting (SB), tribochemical silica coating (TBC), CO₂ laser irradiation, and plasma-enhanced chemical vapor deposition (PECVD-Si coating for 49 min) on surface roughness (Ra), surface morphology, and composite-to-zirconia shear bond strength (SBS). Eighty 3Y-TZP plates were randomly allocated into four groups (n = 20) based on surface conditioning protocol: Group 1 (SB), Group 2 (CO₂ laser), Group 3 (TBC), and Group 4 (PECVD-Si coating for 49 min). From each group, five specimens underwent Ra assessment using a contact profilometer, and five specimens were examined for surface morphology via scanning electron microscopy (SEM). The remaining ten specimens received resin composite buildup, followed by artificial aging. Subsequently, SBS testing was performed using a universal testing machine, and failure modes were evaluated under a stereomicroscope. Statistical analysis was conducted using one-way ANOVA with post hoc Tukey test and chi-square for fracture assessment(α = 0.05). Group 1 (SB) demonstrated the lowest Ra (0.844 ± 0.063 µm) and SBS (12.21 ± 4.6 MPa), whereas Group 4 (PECVD-Si coating for 49 min) exhibited the highest Ra (1.388 ± 0.098 µm) and SBS (30.48 ± 2.5 MPa). Intergroup comparison revealed no statistically significant differences between Groups 2 and 3 for both Ra and SBS values (p > 0.05). However, Groups 1 and 4 differed significantly in both parameters (p < 0.05). PECVD-based silica coating for 49 min demonstrated superior surface conditioning efficacy for 3Y-TZP, yielding significantly higher Ra and SBS values compared to sandblasting, tribochemical silica coating, and CO₂ laser irradiation. Full article

This study evaluated the thermal properties, crystallinity, particle size, morphology, and in vivo local inflammation and persistence of two poly-L-lactic acid (PLLA) injectable implants, Sculptra^® (PLLA-SCA) and GANA V^® (PLLA-GA). PLLA-SCA and PLLA-GA underwent differential scanning calorimetry and X-ray powder diffraction to evaluate their thermal properties and degree of crystallinity. X-ray powder diffraction spectra displayed a sharper, more intense peak for PLLA-GA than PLLA-SCA, with smaller peaks on either side of the main peak of PLLA-GA but not PLLA-SCA. Differential scanning calorimetry thermograms indicated three thermal events for both PLLA-SCA and PLLA-GA. For PLLA-SCA, the first two events occurred between 65 °C and 90 °C, and the third event occurred at 165 °C. For PLLA-GA all three events occurred between 156 °C and 169 °C. Heating samples to 120 °C and cooling to room temperature prior to differential scanning calorimetry resulted in no thermal events being observed between 65–90 °C with either product, while three events were observed with PLLA-GA and one event with PLLA-SCA between 156 °C and 169 °C. The median volume distribution diameter was 46.4 µm for PLLA-SCA and 31.7 µm for PLLA-GA. Scanning electron microscopy showed PLLA-GA particles were irregular in shape, had no sharp edges and had a wrinkled and crimped surface, while PLLA-SCA particles displayed plate-like shapes and had smoother surfaces. In vivo inflammatory reactivity scores indicated a slight reaction for PLLA-SCA at all time points (3.7 ± 1.1, 6.1 ± 1.6, 5.7 ± 1.2 and 6.2 ± 1.2 at 2, 12, 26 and 52 weeks, respectively), while for PLLA-GA, a moderate reaction was observed at 12 and 26 weeks (2.9 ± 1.5, 10.1 ± 1.0, 9.4 ± 0.7 and 7.1 ± 1.3 at 2, 12, 26 and 52 weeks, respectively). PLLA-SCA and PLLA-GA had similar persistence scores at 2, 12 and 26 weeks, while at 52 weeks the score was markedly higher for PLLA-SCA versus PLLA-GA (1.9 ± 0.2 versus 0.7 ± 0.2). In conclusion, PLLA-SCA is more amorphous than PLLA-GA. The single melting point of PLLA-SCA contrasts with the broader spectrum of melting points for PLLA-GA suggests a more homogenous formulation of PLLA-SCA. This, and its less crystalline structure, result in the slower degradation rate and more sustained biological response of PLLA-SCA compared with PLLA-GA. The physiochemical properties of PLLAs affect the biological response in clinical practice and should be taken into consideration when selecting a PLLA treatment for aesthetic use. Full article

Background: Non-absorbable polyvinyl alcohol sponges (Merocel) are widely used in otolaryngology for nasal and ear packing but are prone to bacterial colonization and biofilm formation, which may increase infection risk and drive frequent use of systemic antibiotics. Sustained-release drug delivery systems enable prolonged local antiseptic activity at the site of packing while minimizing systemic exposure. Methods: We developed a sustained-release varnish containing chlorhexidine (SRV-CHX) and coated sterile Merocel sponges. Antibacterial, in vitro, activity against Staphylococcus aureus and Pseudomonas aeruginosa was evaluated using kinetic diffusion assays on agar, optical density (OD₆₀₀) measurements of planktonic cultures, drop plate, ATP-based viability assays, biofilm analysis by MTT metabolic assay, crystal violet bio-mass staining, high-resolution scanning electron microscopy (HR-SEM), and spinning disk confocal microscopy. Results: SRV-CHX-coated sponges produced sustained zones of inhibition on agar plates for up to 37 days against S. aureus and 39 days against P. aeruginosa, far exceeding the usual 3–5 days of clinical sponge use. Planktonic growth was significantly reduced compared with SRV-placebo, and a bactericidal effect persisted for up to 16 days for S. aureus and 5 days for P. aeruginosa before becoming predominantly bacteriostatic. Biofilm formation was markedly inhibited, with suppression of metabolic activity and biomass for at least 33 days for S. aureus and up to 16 days for P. aeruginosa. HR-SEM and confocal imaging confirmed sparse, discontinuous biofilms and predominance of non-viable bacteria on SRV-CHX-coated sponges compared with dense, viable biofilms on the placebo controls. Conclusions: Coating Merocel sponges with SRV-CHX provides prolonged antibacterial and anti-biofilm activity against clinically relevant pathogens. This strategy may reduce dependence on systemic antibiotics and improve infection control in nasal and ear packing applications in otolaryngology. Full article

Carbon-reinforced epoxy laminated composite (CREC) structures are increasingly utilized in high-speed marine vehicles (HSMVs) due to their high specific strength and stiffness; however, they are frequently subjected to impact loads like slamming and aggressive environmental agents during operation. This study experimentally investigates the Compression After Impact (CAI) behavior of CREC plates with varying lamination sequences under both atmospheric and accelerated aging conditions. The samples were produced using the vacuum-assisted resin infusion method with three specific orientation types: quasi-isotropic, cross-ply, and angle-ply. To simulate the marine environment, specimens were subjected to accelerated aging in a salt fog and cyclic corrosion cabin for periods of 2, 4, and 6 weeks. Before and following the aging process, low-velocity impact tests were conducted at an energy level of 30 J, after which the residual compressive strength was measured by CAI tests. At the end of the aging process, after the sixth week, the performance of plates with different layer configuration characteristics can be summarized as follows: Plates 1 and 2, which are quasi-isotropic, exhibit opposite behavior. Plate 1, with an initial toughness of 23,000 mJ, increases its performance to 27,000 mJ as it ages, while these values are around 27,000 and 17,000 mJ, respectively, for Plate 2. It is thought that the difference in configurations creates this difference, and the presence of the 0° layer under the effect of compression load at the beginning and end of the configuration has a performance-enhancing effect. In Plates 3 and 4, which have a cross-ply configuration, almost the same performance is observed; the performance, which is initially 13,000 mJ, increases to around 23,000 mJ with the effect of aging. Among the options, angle-ply Plates 5 and 6 demonstrate the highest performance with values around 35,000 mJ, along with an undefined aging effect. Scanning Electron Microscopy (SEM) and Energy-Dispersive X-ray Spectroscopy (EDS) analyses confirmed the presence of matrix cracking, fiber breakage, and salt accumulation (Na and Ca compounds) on the aged surfaces. The study concludes that the impact of environmental aging on CRECs is not uniformly negative; while it degrades certain configurations, it can enhance the toughness and energy absorption of brittle, cross-ply structures through matrix plasticization. Full article

This work presents the fabrication and a systematic evaluation of an ionic polymer-metal composite (IPMC) sensor, focusing on its potential for human motion monitoring and human–computer interaction. The sensor was fabricated via a solution casting and electroless plating process, and its morphology characterized using scanning electron microscopy. The sensing performance was comprehensively assessed, revealing high sensitivity (1.059 mV/N) in the low-pressure region, a fast response time (~50 ms), and reliable stability over prolonged cyclic testing. Furthermore, the sensor can respond to both the magnitude and rate of applied mechanical stimuli. To explore its application potential, the IPMC was tested in scenarios ranging from input pattern recognition—including distinguishing mouse-click patterns, handwritten letters, and binary-encoded presses—to human motion monitoring, where it effectively captured and differentiated signals from facial expressions, swallowing, breathing, and joint movements. The results suggest that the developed IPMC sensor is a promising candidate for applications in wearable health monitoring and flexible interactive systems. Full article

In order to determine the causes of crack defects in Mn18Cr2 high-manganese wear-resistant steel plates, this paper conducted a systematic analysis of the steel plates’ microstructure, chemical composition, and hardness via metallographic microscopy, field-emission scanning electron microscopy, and Vickers hardness tester. The results indicated that there were folded cracks on the surface of the steel plate. The interior of the cracks was oxidized, and inclusions were observed in the crack gaps. A significant difference in the contents of Mn and Cr elements was detected at the defect locations, indicating that very obvious long-range diffusion of Mn and Cr elements had occurred during long-term high-temperature oxidation. The crack defects on the surface of the steel plate were related to the inheritance of the original cracks on the surface of the cast billet before rolling. There were cracks on the surface of the cast billet; the oxide scale and inclusions inside the cracks had not been completely removed. Multiple passes of rolling led to the cracks and oxide scale being pressed into the steel surface, thereby forming folding defects. The fine grain strengthening and deformation twinning generated by rolling deformation formed the hardened layer on the surface, resulting in higher surface hardness than core hardness. The austenite grain size inside the steel plate was in the range of 23–30 μm, and the hardness was around 275 HV. The grain size near the surface of the steel plate was around 10 μm. The surface hardness was 351 HV, which was higher than the core hardness of the steel plate. Full article

The increasing threat posed by micrometeoroids and orbital debris to in-orbit spacecraft necessitates the development of lightweight and deformable shielding systems capable of withstanding hypervelocity impacts. Ultra-high-molecular-weight polyethylene (UHMWPE) films, owing to their high specific strength and energy-absorption capacity, present a promising candidate for such applications. However, the hypervelocity impact response of thin, highly oriented UHMWPE films—distinct from bulk plates or composites—remains poorly understood, particularly for micron-scale particles at velocities relevant to space debris (≥8 km/s). In this study, we systematically investigate the impact resistance of 0.1 mm UHMWPE films using a plasma-driven microparticle accelerator and a hypervelocity dust gun to simulate impacts by micron-sized Al₂O₃ and Fe particles at velocities up to ~8.5 km/s. Through detailed analysis of crater morphology via scanning electron microscopy, we identify three distinct damage modes: plastic-dominated craters (Type I), fracture-melting craters (Type II), and perforations (Type III). These modes are correlated with impact energy and particle size, revealing the material’s transition from large-scale plastic deformation to localized thermal softening and eventual penetration. Crucially, we provide quantitative penetration thresholds (e.g., 2.25 μm Al₂O₃ at 8.5 km/s) and establish a microstructure-informed damage classification that advances the fundamental understanding of UHMWPE film behavior under extreme strain rates. Our findings not only elucidate the energy-dissipation mechanisms in oriented polymer films but also offer practical guidelines for the design of next-generation, flexible spacecraft shielding systems. Full article

Objectives: Against common belief, mandibular condyle fractures are not that rare, with morbidity rates ranging from 19 to 52%, depending on actual literature sources. Practitioners try to improve the surgical techniques applied to obtain the most satisfactory anatomical and functional effect. The purpose of this study is to identify the relationships that affect bone loss around screws and plates in mandibular condylar process fractures treated surgically using the Open Reduction and Internal Fixation (ORIF) technique. Materials and Methods: Our research covered 276 fractures of the base, low and high neck of the condylar process. No formal sample size calculation was performed; the study enrolled patients treated at the Department during the last 4 years, based on informed consent granted both prospectively and retrospectively compares to the actual treatment time. The study group was selected based on injury type and the ability to implement surgical treatment. The imaging modality selected for the study was computed tomography (CT), which was assessed in each case by the same operator. Therefore, there was no need to account for inter-rater variability in the results. Based on CT scans, we studied various parameters, including bone healing in the fracture area, bone loss in the screws and plates area, change in the length of the mandibular ramus following osteosynthesis and on the opposite side after 12 months, as well as deformities of the mandibular head. Results: Using screws and plates is the gold standard for treating mandibular condylar process fractures. The number of screws used affects the bone loss ratio around head of the screw. Another factor that impacts the results achieved is the distance from the plate edge to the lateral pole of the mandibular head. Statistical evaluation indicated that proximity to the lateral pole is a risk factor for bone resorption at the plate edge. Conclusions: Based on the collected data, it is possible to predict bone loss, determine the location and selection of plates and screws, as well as to plan the procedure, achieving the lowest possible loss rates. Full article

Background/Objectives: Down Syndrome (DS) is frequently associated with oral-motor dysmorphologies, like oral hypotonia, tongue protrusion, short palate, and malocclusion, compromising the oral functions of sucking, chewing, swallowing, and speech production. Therapeutic interventions with stimulating palatal plates (SPP) have been proposed to prevent and improve oral-motor dysmorphologies in DS. This study proposes a new digital workflow for the manufacturing and use of a modified SPP. Methods: We report the application of the new workflow to five clinical cases, all infants with DS showing oral-motor disorders, aged between 5 and 11 months. The workflow is described step-by-step, from the mouth scanning protocol and model printing to SPP manufacturing and delivering, and assessment of oral-morphological features and language abilities via video captures and parental questionnaires. Key novel features include an SPP with an acrylic extension with a pacifier terminal and, importantly, the use of an infant-friendly intraoral scanner. Results: The new workflow had good acceptability by infants and parents, offering a safe, easy-to-implement, and feasible solution for SPP design, as it avoided the high risks associated with impression materials. It also supported the use of the SPP to promote tongue stimulation, retraction, and overall oral-muscle function in oral-motor disorders in children with DS, especially in infants. Conclusions: Within the limitations of the current study, it was shown that the proposed digital workflow constitutes a viable and infant-friendly approach to the production and use of a modified SPP, and thus promises to contribute to improving oral morphology and auditory-motor language abilities. Full article

Background: Several minimally invasive techniques have been introduced to augment horizontal ridge volume for prosthetically driven implant placement, utilizing different biomaterials to enhance regenerative outcomes. This article presents two clinical cases illustrating a tunneling approach for horizontal alveolar ridge augmentation using a combination of xenogeneic bone graft, hyaluronic acid, and an acellular dermal matrix. Methods: A single vertical incision was made mesial to the bone defect and a dermal matrix was suitably shaped and positioned into the subperiosteal tunnel. Subsequently, the bone graft was inserted between the dermal matrix and the buccal bone plate. Primary wound closure was achieved. After six months, implants were placed. For each patient, an optical scan was performed at baseline (T₀), at six months post-operative ridge augmentation surgery (T₁) and at two months post-implant insertion (T₂). A digital measurement of the horizontal ridge thickness was performed at each inserted implant site. Clinical parameters and patient postoperative morbidity were recorded. Results: The procedure was well tolerated by the patients. No postoperative clinical complications were observed. The mean tissue thickness achieved at T1 was recorded to be 13.3 mm. The same value was recorded at T2. Conclusions: This technique allowed the placement of prosthetically guided implants, with minimal morbidity and no observed complications. Further studies analyzing the histology of newly formed bone and performing three-dimensional radiological examinations to confirm the effectiveness of the surgical technique are warranted to validate these preliminary findings. Clinical Trial Number (NIH): NCT06424223 Full article

Background/Objectives: Three-dimensional (3D) cell cultures are increasingly used because 3D cell aggregates better mimic tissue-level biological mechanisms and support studies of tissue physiology and drug screening. However, existing laboratory methods and commercial microwell platforms often yield inconsistent results and can be error-prone, time-consuming, or costly. The objective of this work was to develop a reproducible, high-yield, and cost-effective approach for generating homogeneous cell aggregates using custom 3D-printed microwell stamps. Methods: Custom conical and semi-spherical microwell stamps were fabricated using 3D printing. Stamp resolution was characterized by scanning electron microscopy (SEM). Negative imprints were cast in polydimethylsiloxane (PDMS), a biocompatible and hydrophobic polymer conducive to cell aggregation. These PDMS microwells were then used to generate pluripotent stem cell aggregates (embryoid bodies, EBs) and tumor spheroids from adherent cancer cell lines. Results: The 3D-printed stamps produced high-resolution conical and semi-spherical microwells in PDMS. Semi-spherical microwells enabled rapid, simple, and cost-effective formation of pluripotent stem cell aggregates that were homogeneous in size and shape. These aggregates outperformed those produced using commercial microwell plates and ultra-low attachment plates. The fabricated microwells also generated uniform tumor spheroids from adherent cancer cells, demonstrating their versatility. Conclusions: The in-house 3D-printed microwell stamps offer a reproducible, efficient, and economical platform for producing homogeneous cell aggregates. This system improves upon commercial alternatives and supports a broad range of applications, including pluripotent stem cell embryoid body formation and tumor spheroid generation. Full article