Search Results (498)

Background/Objectives: This study aimed to evaluate the clinical feasibility of a novel desktop micro-computed tomography (micro-CT) scanner for digital impressions through comprehensively assessing its dimensional trueness and morphological accuracy in comparison with other optical-based scanners. Methods: A modified reference model was used to create ten silicone impressions and corresponding plaster models. Four digitization protocols were evaluated: (1) direct scanning of impressions via micro-CT scanner (MCTI), (2) extraoral scanning of impressions via F8 scanner (F8I), (3) extraoral scanning of plaster models via F8 scanner (F8PM), and (4) intraoral scanning of plaster models using Trios 5 scanner (IOSPM). Dimensional trueness was quantified via six linear measurements, and morphological accuracy (trueness and precision) was assessed by 3D surface deviation analysis. Results: Statistically significant differences in linear measurements between the digital impressions and the reference model were observed (p < 0.05). MCTI, F8PM and IOSPM demonstrated higher dimensional trueness than F8I. Although all methods showed high morphological precision, F8I (398.5 ± 43.0 µm) exhibited significantly greater root mean square (RMS) deviations for morphological trueness than MCTI (114.8 ± 42.2 µm), F8PM (142.1 ± 27.7 µm) and IOSPM (134.6 ± 12.0 µm) (p < 0.01). MCTI also demonstrated the highest reliability for morphological trueness according to relative standard deviation (RSD) analysis, with RSD values of 30.83% for MCTI, 41.80% for F8I, 37.26% for F8PM, and 42.55% for IOSPM. Conclusions: The novel micro-CT scanner enables accurate and reliable direct digitization of dental impressions. Its performance is comparable to scanning plaster models with high-end scanners and significantly superior to direct optical scanning of impressions, making it a promising alternative in digital dental workflow. Full article

Background: Otitis media with effusion (OME) is a widespread condition that causes hearing impairment, particularly in pediatric populations. Existing non-absorbable tubes often require elective or unplanned removal surgery. Bioabsorbable polylactic acid (PLA) offers a promising alternative due to its inherent biocompatibility and tunable degradation characteristics. In this study, we designed, fabricated, and comprehensively evaluated a novel PLA middle-ear ventilation tube. Methods: Bioabsorbable PLA tubes were designed and fabricated based on commercial models. In vitro biocompatibility was assessed according to ISO 10993 guidelines. A guinea pig model was used to perform in vivo evaluations, including otoscopic examinations, auditory brainstem response (ABR) measurements, micro-computed tomography (micro-CT) imaging, and histological analyses. Results: The PLA tubes were successfully designed and fabricated, exhibiting dimensions comparable to those of commercially available products. In vitro testing confirmed their biocompatibility. In vivo observations revealed that the PLA segments remained stable, with no significant inflammation detected. ABR measurements revealed no adverse impacts on hearing function. Micro-CT imaging confirmed tube integrity and indicated initial signs of degradation over a 9-month period, as evidenced by radiographic morphology. Histological analyses indicated a favorable tissue response with minimal foreign body reaction. Conclusions: The developed PLA middle-ear ventilation tube represents a highly promising alternative to conventional non-absorbable tubes. It demonstrates excellent biocompatibility, preserves auditory function, and exhibits a controlled degradation profile. This preclinical study provides strong support for further investigation and subsequent clinical trials to validate its safety and efficacy in human patients. Full article

An IN738 alloy with a high Al and Ti contents induces a significant cracking tendency during laser powder bed fusion (LPBF) processing, leading to a mismatch between printability and mechanical properties. Modification of alloy compositions is an effective strategy to enhance the printability and mechanical properties of nickel-based superalloys via LPBF. In this study, the effects of adding 5 wt.%Co on the printability and mechanical properties of LPBF-fabricated IN738 were investigated by using three-dimensional high-resolution micro-computed tomography (micro-CT), electron backscatter diffraction (EBSD), and quasi-static room-temperature tensile tests. The results show that adding 5 wt.%Co can significantly reduce the defect rate and defect size of the LPBF-fabricated IN738 alloy, remarkably improve alloy densification, and optimize printability. Meanwhile, compared with the LPBF-fabricated IN738 alloy, the 5 wt.%Co-IN738 alloy exhibits an excellent balance of strength and ductility in horizontal and vertical directions, both LPBF-fabricated and heat-treated. These results are anticipated to offer valuable guidance for the development of LPBF-fabricated Ni-based superalloys that achieve a favorable balance between printability and mechanical properties. Full article

Diagnosing fractures in hummingbirds is challenging because of their small size. This study evaluated the diagnostic performance and inter-reviewer agreement of four imaging modalities—conventional radiography, dental radiography, micro-computed tomography (micro-CT), and three-dimensional (3D)-reconstructed images from micro-CT scans—for identifying fractures in 16 ruby-throated hummingbirds (Archilochus colubris) admitted to a wildlife hospital. Six independent reviewers, with or in training for a specialty in veterinary radiology or wildlife medicine, assessed randomized image sets. Gross dissection of the carcasses using dermestid beetle larvae established the gold standard. Diagnostic performance metrics—sensitivity, specificity, predictive values, and likelihood ratios—were calculated for each modality. Inter-reviewer agreement was assessed using Fleiss’ kappa. Our results demonstrated that advanced imaging techniques improved diagnostic performance and inter-reviewer agreement compared to traditional radiography. While specificity (>88%) was comparable to other small animal studies, the sensitivity did not exceed 50% across all modalities. This low sensitivity reflects the challenges posed by minimal fracture displacement and hummingbirds’ extremely small size. Only 3D images achieved high positive likelihood ratios and superior inter-reviewer agreement, highlighting the unique value of 3D visualization in complex anatomical evaluations. Overall, the minute structures of hummingbirds present inherent diagnostic limitations, underscoring that negative radiographic results must be interpreted cautiously, and the possibility of false negatives should prompt consideration of advanced or follow-up imaging when clinical suspicion persists. Full article

Lacustrine shale oil in the Chang 7 Member of the Ordos Basin is controlled by a multi-scale pore–throat system in which oil occurrence, spontaneous imbibition, and pore-structure evolution are tightly coupled. In this study, nitrogen adsorption and micro-computed tomography (μCT) were employed to characterize pore-size distribution and connectivity, whereas nuclear magnetic resonance (NMR) T₂ relaxation was utilized to classify oil occurrence states, and X-ray diffraction (XRD) and total organic carbon (TOC) analyses were performed to determine mineralogical and organic compositions. Spontaneous imbibition experiments were conducted at 60 °C and subsequently extended to temperature–pressure sequence tests. The Chang 7 shale exhibits a stratified pore system in which micropores, mesopores, and macropores jointly define a three-tier “micropore adsorption–mesopore confinement–macropore mobility” pattern. As pore size and connectivity increase, the equilibrium imbibed mass and initial imbibition rate both rise, while enhanced wettability (contact angle decreasing from 81.2° to 58.7°) further strengthens capillary uptake. Temperature elevation promotes imbibition, whereas increasing confining pressure suppresses it, revealing a “thermal enhancement–pressure suppression” behavior. μCT-based network analysis shows that imbibition activates previously ineffective pore–throat elements, increasing coordination number and connectivity and reducing tortuosity, which collectively represents a capillary-driven structural reconfiguration of the pore network. When connectivity exceeds a threshold of about 0.70, the flow regime shifts from interface-dominated to channel-dominated. Building on these observations, a multi-scalecoupling framework and a three-stage synergistic mechanism of “pore-throat activation–energy conversion–structural reconstruction” are established. These results provide a quantitative basis for predicting imbibition efficiency and optimizing capillary-driven development strategies in deep shale oil reservoirs. Full article

Periapical radiographs remain the first-line imaging modality in endodontics due to accessibility and low radiation dose, whereas cone-beam computed tomography (CBCT) is reserved for inconclusive cases or suspected anatomical complexity. We propose a physics- and geometry-aware preprocessing pipeline coupled with sliding-window Viterbi tracking to enhance canal visibility and recover plausible root canal trajectories directly from routine periapical images. The pipeline standardizes row-wise brightness, compensates for the cone-like tooth density profile (Tukey window), and suppresses noise prior to dynamic-programming inference, requiring only minimal operator input (two-point orientation and region of interest). In a retrospective evaluation against micro-computed tomography (micro-CT)/CBCT reference anatomy, the approach accurately localized canals on periapicals under study conditions, suggesting potential as a rapid, chairside aid when 3D imaging is unavailable or deferred. Full article

The repair of large segmental bone defects remains a major clinical challenge. Traditional bone repair materials often suffer from mismatched degradation rates, insufficient mechanical strength, or limited bioactivity. Biodegradable zinc alloys have emerged as potential alternatives due to their suitable degradation rate and good biocompatibility, though their bioactivity requires further enhancement. In this study, a zinc phosphate (ZnP) coating was applied on the surface of zinc–copper (Zn–Cu) alloy via a phosphate chemical conversion method, and the corrosion resistance, wear resistance, and osteogenic properties of the coating were systematically evaluated. Results showed that the ZnP coating prepared at pH = 2.5 exhibited a dense structure and high crystallinity, reducing the corrosion rate to 0.010 μm/year and increasing the ultimate tensile strength to 117.03 ± 0.78 MPa, significantly improving the wear and corrosion resistance of the alloy. In vivo experiments demonstrated that the material markedly promoted new bone formation and osseointegration. Micro-computed tomography (Micro-CT) revealed that key indicators such as bone volume fraction (approximately 50.26%) and trabecular number (approximately 161.31/mm³) were superior to those of the β-tricalcium phosphate (β-TCP) group and the control group. Histological analysis confirmed its excellent osteogenic activity and mineralization capacity. Biosafety assessments indicated no systemic toxic reactions. The ZnP-coated Zn-1Cu alloy showed promising application in treatment of bone defect. Full article

Estrogen deficiency is a primary cause of osteoporosis, compromising bone mineral density that may impair peri-implant healing. Given the compromised bone environment associated with estrogen deficiency, strategies such as particle reduction via sonochemistry are promising approaches to enhance regenerative outcomes. However, its effects in promoting bone formation remain insufficiently explored. Therefore, this study evaluated the potential of two sonicated biomaterials to improve peri-implant repair in ovariectomized rats. Fifty female rats were allocated into five groups: blood clot (CLOT), Biogran^® (BGN), sonicated Biogran^® (BGS), Bio-Oss^® (BON), and sonicated Bio-Oss^® (BOS). Tibial peri-implant defects were created 30 days after ovariectomy and analyzed 28 days later by removal torque, microcomputed tomography, and confocal microscopy. BGS exhibited the highest removal torque (6.28 Ncm), followed by BON (5.37 Ncm), BOS (3.92 Ncm), BGN (3.15 Ncm), and CLOT (2.58 Ncm). Micro-CT revealed bone volume fraction (BV/TV) values of 8.07% (CLOT), 6.47% (BOS), 6.02% (BGS), 5.55% (BGN), and 2.84% (BON). For the trabecular number (Tb.N), BGS (1.11 mm⁻¹) showed a significant increase compared with BGN (0.69 mm⁻¹), p < 0.05. These findings show that sonochemically modified bioactive glass improves mechanical stability and trabecular microarchitecture under estrogen-deficient conditions. However, further studies are needed to standardize sonication parameters for different biomaterials and expand their translational applicability. Full article

Short fibre-reinforced adhesives (SFRAs) are increasingly used in wind turbine blades to enhance stiffness and fatigue resistance, yet their heterogeneous microstructure poses significant challenges for predictive modelling. This study presents a fully automated digital workflow that integrates micro-computed tomography (µCT), image processing, and finite element modelling (FEM) to investigate the mechanical response of SFRAs. Our aim is also to establish a computational foundation for data-driven modelling and future AI surrogates of adhesive joints in wind turbine blades. High-resolution µCT scans were denoised and segmented using a hybrid non-local means and Gaussian filtering pipeline combined with Otsu thresholding and convex hull separation, enabling robust fibre identification and orientation analysis. Two complementary modelling strategies were employed: (i) 2D slice-based FEM models to rapidly assess microstructural effects on stress localisation and (ii) 3D voxel-based FEM models to capture the full anisotropic fibre network. Linear elastic simulations were conducted under inhomogeneous uniaxial extension and torsional loading, revealing interfacial stress hotspots at fibre tips and narrow ligaments. Fibre clustering and alignment strongly influenced stress partitioning between fibres and the matrix, while isotropic regions exhibited diffuse, matrix-dominated load transfer. The results demonstrate that image-based FEM provides a powerful route for structure–property modelling of SFRAs and establish a scalable foundation for digital twin development, reliability assessment, and integration with physics-informed surrogate modelling frameworks. Full article

Additive manufacturing (AM) has rapidly evolved due to its design flexibility, ability to enable personalized fabrication, and reduced material waste. In the medical field, fused filament fabrication (FFF) facilitates the production of individualized anatomical models for surgical preparation, education, medical imaging, and calibration. However, the lack of filaments with X-ray attenuation similar to that of biological hard tissues limits their use in radiological imaging. To address this limitation, a radiopaque filament was developed by incorporating gadolinium oxide (Gd₂O₃) into a biodegradable poly(lactic acid) (PLA) matrix at 1, 3, and 5 wt.%. Thermal and rheological properties were characterized using differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), and melt flow index (MFI) analyses, revealing minor variations that did not affect printability under standard FFF conditions (200 °C nozzle, 60 °C build plate, 0.12 mm layer height). Microstructural analysis via field emission scanning electron microscopy (FESEM), energy-dispersive X-ray spectroscopy (EDX), elemental mapping, and micro-computed tomography (micro-CT) confirmed homogeneous Gd₂O₃ dispersion without nozzle blockage. Radiopacity was evaluated using gyroid infill cubes, and increasing Gd₂O₃ content enhanced X-ray attenuation, with 3 wt.% Gd₂O₃ reaching Hounsfield Unit (HU) values comparable to cortical bone. Finally, the L1 vertebra phantom fabricated from the 3 wt.% Gd₂O₃ filament exhibited mean HU values of approximately +200 to +250 HU at 50% infill density (trabecular bone region) and around +1000 HU at 100% infill density (cortical bone region), demonstrating the filament’s potential for producing cost-effective, radiopaque, and biodegradable phantoms for computed tomography (CT) imaging. Full article

Advanced cell-based therapies, including immunotherapy, regenerative medicine, and other biotechnological applications, require large quantities of viable mammalian cells for research and clinical use. Conventional enzymatic harvesting methods, such as trypsini-zation, can compromise cell integrity and reduce viability. This study investigates an al-ternative temperature-responsive approach using alginate beads incorporated with poly(N-isopropylacrylamide) (PNIPAAm), a polymer exhibiting a lower critical solution temperature (LCST) of approximately 32 °C. This system enables temperature-controlled cell detachment while preserving cellular structure and extracellular matrix components, thereby potentially improving post-harvest viability compared to trypsin treatment. Ho-mogeneous alginate hydrogel beads were synthesized using a standard infusion pump and ionically crosslinked with calcium cations. The beads were characterized by scanning electron microscopy (SEM) for morphology and by Fourier-transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), and micro-computed tomography (µ-CT) for compositional and thermal analysis. Mouse fibroblast cells (L929 cell line) were cultured on the beads, and their proliferation and viability were assessed using CCK-8 and Live/Dead assays, demonstrating significant cell growth over seven days. The results suggest that PNIPAAm-modified alginate beads provide a promising, enzyme-free platform for efficient mammalian cell harvesting and delivery, with potential applications across advanced cell manufacturing and therapeutic technologies. Full article

Microneedle array-based drug delivery offers a minimally invasive and safe approach for breaching the skin barrier, enabling localized and targeted treatment—an advantage particularly valuable in chronic condition management, such as rheumatoid arthritis (RA). RA presents a multifaceted pathophysiology, often necessitating long-term pharmacological management. However, conventional oral administration may lead to systemic drug distribution, increasing the likelihood of adverse effects, and ultimately undermining therapeutic efficacy. In this study, a hollow microneedle array was employed for effective delivery of Tofacitinib and the antioxidant N-acetylcysteine (NAC). A comprehensive evaluation was conducted across multiple levels, in which inflammation and cartilage degradation were assessed histologically using hematoxylin-eosin (H&E) and Safranin O–Fast Green staining. Radiologically, micro-computed tomography (micro-CT) was employed to visualize bone structure alterations. On the molecular level, enzyme-linked immunosorbent assay (ELISA) was used to quantify inflammatory cytokines and oxidative stress markers. Furthermore, differentially expressed genes and enriched signaling pathways were identified through transcriptomic profiling pre- and post-treatment. And the potential regulatory targets and mechanistic insights into the therapeutic response were elucidated through correlation analyses between gene expression profiles and pathological indicators. This study provides a mechanistic and computational basis for precision targeted therapy, validates the efficacy and safety of microneedle delivery in a rheumatoid arthritis (RA) model, and demonstrates its potential application in local drug delivery strategies. Full article

Regeneration of jawbone defects poses major challenges. The combination of dental pulp stem cells (DPSCs) or DPSC-derived extracellular vesicles (EVs) with bone substitute materials shows promising potential for bone tissue engineering in vitro. This study evaluated the in vivo bone regeneration potential of DPSCs and EVs with bone graft substitutes in a novel intrabony defect model. DPSCs were isolated from 35 male Sprague–Dawley rat incisors, and EVs were collected from the cell culture medium. DPSCs were seeded onto alloplastic and xenogeneic bone graft materials and implanted into bone defects. Control groups received bone substitutes without DPSCs or EVs. Micro-computed tomography (µCT) was performed at 12 and 24 weeks post-implantation to assess bone volume (BV), bone density (BD), trabecular thickness (Tr.Th), bone growth rate (BGR), and bone-to-mineral ratio (BMR). Both graft types increased BV and BD, with no significant differences between them. Tr.Th increased across all treatments after 24 weeks, indicating ongoing bone remodeling. Notably, xenogeneic grafts combined with DPSCs and EVs significantly improved BGR (p = 0.034) and BMR (p = 0.021) compared to alloplastic grafts with DPSCs. Xenogeneic bone grafts combined with DPSCs and EVs appear to be a promising approach for bone regeneration of alveolar bone defects. Full article

X-ray micro-computed tomography (Micro-CT) is an advanced technique capable of non-destructive detection of internal defects in materials. Fiber-reinforced polymer (FRP) laminates are prone to forming defects such as pores during the manufacturing process, which significantly affect their mechanical properties. In this study, Micro-CT technology was employed to conduct non-destructive testing on carbon fiber (CFRP), glass fiber (GFRP) and carbon/glass hybrid (C/G) laminates. Combined with the U-Net++ deep learning model, precise segmentation and three-dimensional reconstruction of pores were achieved. A systematic quantitative analysis was carried out on the distribution, size, volume and porosity of pores in six specimens with two layup angles (0/90 and ±45). The research results show that the pores in CFRP are mainly dispersed micro-pores and are relatively evenly distributed; the porosity of GFRP is the highest, and large interlaminar pores are prone to forming. The porosity fluctuates sharply in the thickness direction, revealing that the interlaminar interface is a defect-sensitive area. This provides a reliable quantitative basis and theoretical support for optimization and defect assessment. Full article

This study presents a systematic approach to enhancing the mechanical performance of composite materials for submarine applications by quantitatively evaluating and controlling internal micro-voids generated during the manufacturing process. Three non-destructive evaluation techniques—ultrasonic testing, optical microscopy, and micro-computed tomography (Micro-CT)—were employed to assess the void content in fiber-reinforced composite specimens fabricated under various processing conditions. Tensile and flexural strength tests were conducted to investigate the correlation between the void content and mechanical properties. Among the methods, ultrasonic testing exhibited the strongest negative correlation (correlation coefficient = −0.703), confirming its effectiveness as a representative non-destructive evaluation technique. Furthermore, the statistical design of experiments, including factorial design, steepest ascent method, and response surface methodology (RSM), identified defoamer concentration and mixing time as the most influential process parameters in void reduction. The optimal processing conditions were determined to be 0.049% defoamer and 232 min of mixing. Under these conditions, the void content was minimized, and the mechanical properties were significantly improved. These findings offer practical guidance for void control and non-destructive evaluation in large-scale composite structures, contributing to improved reliability in underwater structural applications. Full article