Search Results (1,438)

Silica-based bioceramics are promising bone substitutes with tunable degradation and mechanical properties. We aimed to assess bone response in critical-size calvarial defects in rats, empty or filled with 3D-printed sphene ceramic (CaTiSiO₅) scaffolds produced using direct ink writing from preceramic polymers and reactive fillers. Scaffold characterization was performed using scanning electron microscopy, X-ray diffraction, porosity analysis, and compressive strength testing. Bilateral cylindrical 5 mm calvarial defects were created in 20 rats: one was randomly filled with sphene scaffold, while the contralateral remained empty. Ten animals were killed at 4 weeks, the rest at 8 weeks. Specimens were collected for micro-X-ray computed tomography (micro-CT) analysis, followed by undecalcified histology. The scaffolds exhibited porous structure with complete sphene phase purity and compressive strength of 17.91 MPa (SD 4.6). In vivo, no adverse event was noted during healing. Overall bone regeneration—as measured by BV/TV—was comparable between groups: Bone volume/total volume (BV/TV) increased over time in the empty and sphene groups, reaching ~40%, with no significant differences between groups or time points. BV/TV was significantly higher in the external regions of the defects compared to the internal areas in both groups at the two time points. The sphene group showed a significantly greater volume of new bone extending beyond the original cortical boundary at both 4 and 8 weeks (p = 0.013). In the sphene group histology revealed partial bone ingrowth within the scaffold, while bone in the control group was limited to defect edges. After 8 weeks, new bone adjacent to the cortical surface was thicker in the sphene group (p < 0.05). These initial findings are consistent with prior preclinical studies, supporting the biocompatibility and osteoconductive nature of sphene ceramic scaffolds. Full article

Background: Post-traumatic osteoarthritis (PTOA) lacks effective disease-modifying therapies that preserve joint structure while promoting tissue repair. This study aimed to evaluate the therapeutic efficacy and underlying mechanism of Biluo Qianyuan Formula (BLQYF), a standardized herbal formulation derived from clinical practice, as a potential disease-modifying alternative to celecoxib in a murine model of PTOA. Methods: A murine PTOA model was established and treated with BLQYF at different doses, with celecoxib serving as a pharmacological comparator. Safety was assessed by hepatic and renal toxicity analyses. Therapeutic effects were evaluated using micro-computed tomography (micro-CT) and histological staining. Network-based integrative analyses were conducted to identify key regulatory targets, followed by experimental validation in fibroblast-like synoviocytes. Results: BLQYF was well tolerated under the experimental conditions, with no detectable hepatic or renal toxicity at therapeutic doses. Micro-CT and histological analyses demonstrated that BLQYF dose-dependently mitigated subchondral bone deterioration, enhanced cartilage regeneration, and restored collagen deposition. At higher doses, BLQYF showed therapeutic efficacy comparable to celecoxib, with superior outcomes regarding cartilage reparation. Mechanistically, integrative analyses identified fibronectin 1 (FN1) as a central regulatory hub. Validation experiments confirmed that BLQYF suppressed FN1, MMP3, and TGF-β expression in fibroblast-like synoviocytes, thereby attenuating inflammation and extracellular matrix degradation. Conclusions: These findings support BLQYF as a promising disease-modifying therapeutic candidate for PTOA and highlight the fibroblast–FN1 axis as a novel pharmacological target for intervention. Full article

This study examines the carbonation behavior and CO₂ storage potential of a Ca-rich alkali-activated binder produced entirely from industrial residues-ladle furnace slag (LFS), coal ash (CA), and cement kiln dust (CKD). The system was designed as a one-part alkali-activated material (AAM), with CKD acting as an internal activator, and subjected to ambient curing, water curing, and accelerated CO₂ curing at ambient pressure. Phase evolution, microstructural development, and pore-structure characteristics were investigated using X-ray diffraction, FTIR spectroscopy, DSC–TG analysis, scanning electron microscopy, and X-ray micro-computed tomography, together with measurements of density, water absorption, and compressive strength. Loss-on-ignition measurements combined with chemical analysis were further used to quantify CO₂ uptake and evaluate the degree of carbonation of the binder system. CO₂ curing fundamentally altered the reaction pathway of the binder, shifting it from hydration-dominated to carbonation-controlled phase evolution, leading to the decomposition of calcium-bearing hydrates and complete carbonation of non-hydraulic γ-belite with the formation of vaterite, aragonite, and calcite. These transformations induced pronounced microstructural densification, reflected in a near-doubling of compressive strength (>48 MPa), increased apparent density, reduced water absorption, and simplified pore-network topology. A preliminary carbon footprint assessment indicates that the production of 1 m³ of the developed LFS–CA–CKD concrete generates about 14.36 kg CO₂-eq, while the carbonation process enables significant CO₂ sequestration, resulting in a net negative carbon balance. The results demonstrate that controlled carbonation is an effective post-treatment strategy for waste-derived alkali-activated binders, enabling simultaneous performance enhancement and permanent CO₂ sequestration. Full article

Background/Objectives: Root canal procedures on multi-rooted teeth, including first molars, depend on experience, tactile perception, and anatomical knowledge to avoid perforation in the furcation region. Studies using various methodologies and populations have reported discrepant findings on pulpal floor thickness. No study using micro-computed tomography (Micro-CT), the gold standard, has been conducted on a Black South African sample to evaluate pulpal floor thickness. Methods: In this cross-sectional, descriptive, quantitative study, Micro-CT scans of 91 maxillary and 77 mandibular first molars were reconstructed in 3D and oriented according to a reference plane along the cemento-enamel junction using Avizo software. Measurements were taken from the midpoint of the pulpal chamber floor to the perpendicular point on the furcation. In maxillary molars, an additional measurement between the mesiobuccal and distobuccal roots was taken. The effects of arch, side, age, and sex were assessed. Results: Neither sex, arch, nor side had a significant influence on the pulpal floor thickness. The central mandibular and maxillary pulpal floor thicknesses increased significantly with aging, while the effect on the buccal maxillary pulpal floor thickness was not significant. The mean central mandibular and maxillary pulpal floor thicknesses were 2.66 and 2.83 mm, respectively, while the buccal maxillary pulpal floor thickness was significantly smaller at 2.37 mm. Conclusions: More accurate and repeatable findings compared to the literature could be attributed to the use of Micro-CT, which provides higher resolution images, and to Avizo, which enables precise localization of 3D points. Variations from the literature might also be explained by differences in the age and geographical origin of the samples. Full article

Objectives: To determine the most favourable Micro-Implant (MI) insertion site along the mandibular buccal shelf (MBS), using Cone Beam Computed Tomography (CBCT). Methods: This retrospective study assessed CBCT scans from 90 Portuguese patients (32 males and 58 females, aged 14 to 40 years). Paired MBS sites were determined. Comparative and correlation analyses were performed at p < 0.05. Results: A significant increase in MBS width was observed from the mesial to the distal direction (p < 0.001). Conversely, both the MBS steepness and cortical bone thickness significantly decreased from mesial to distal (p < 0.001). Significant negative correlation was also found between age and cortical bone thickness adjacent to the distobuccal cusp and distal tangent of both mandibular second molars (r ≤ −0.373, p ≤ 0.007). Furthermore, significant asymmetric differences were identified between the right and left MBS steepness as well as in the paired cortical bone thickness at the mesiobuccal cusp, buccal groove, and distobuccal cusp of the mandibular second molar (p ≤ 0.016). Conclusions: The results indicate that although there are sufficient MBS width and cortical bone thickness, vestibular to the mandibular second molar for MI insertion, the sites towards the distal root of the mandibular second molar are more favourable when considering MBS steepness. These findings are consistent for both sexes and apply to young and old individuals. Full article

This paper investigates the fatigue and residual strength behavior of recycled carbon fiber reinforced plastics (rCFRPs) with different fiber architectures in an epoxy resin matrix: a unidirectional (UD) rCFRP and a non-crimp fabric (NCF) composite. Due to the research gap in fatigue testing of recycled carbon fiber-reinforced plastics with quasi-continuous fiber reinforcement, their fatigue properties are investigated in this article. The objective of the present study is to contribute to the broader goal of integrating recycled carbon fibers as quasi-continuous fiber reinforcement in structural applications by understanding their failure behavior. To determine suitable stress levels for fatigue testing, quasi-static tensile tests are conducted first. Subsequently, fatigue tests are performed with a stress ratio of 0.1. Damage evolution is documented by a continuous recording of the stiffness degradation. For the unidirectional material, an S-N_f curve is created based on three stress levels. The curve can be described with a logarithmic equation. Fatigue testing of the NCF laminate is performed at a single stress level. Subsequent residual strength tests using standard specimens show no clear correlation between the number of load cycles of pre-cycling and residual strength, but indicate a sudden-death behavior for both composites. For further investigation of the damage behavior, in situ residual strength tests are carried out using a combination of acoustic emission analysis and micro-computed tomography (µCT) imaging. This investigation is intended to illustrate crack initiation and propagation three-dimensionally after pre-cycling and during residual strength tests. The results demonstrate a significant influence of the microstructure on the failure behavior. Full article

Fracture healing is a multistage regenerative process requiring the coordinated regulation of inflammation, osteogenesis, and bone remodeling, yet pharmacological agents that effectively modulate these processes remain limited. Adenophorae Radix (AR), a traditional medicinal herb used for tissue repair, has not been mechanistically investigated in skeletal regeneration. In this study, a mouse femoral fracture model was employed to evaluate the effects of short-term (7 days) and long-term (5 weeks) oral administration of AR. Bone regeneration was assessed using micro-computed tomography, histological staining, and quantitative real-time polymerase chain reaction. Network pharmacology and molecular docking were applied to predict bioactive AR constituents and their target pathways, followed by in vivo validation. Short-term AR treatment significantly upregulated osteogenic markers, including RUNX2 and osteocalcin, in the bone marrow, indicating early activation of osteoblast differentiation. Long-term administration enhanced bone mineral density, trabecular organization, and callus maturation. Network pharmacology analysis identified cycloartenol acetate, β-sitosterol, and mandenol as major active compounds targeting osteogenesis- and osteoclast-related pathways, converging on HIF1A, PTGS2, and PPARG. Molecular docking demonstrated strong binding affinities between these compounds and their predicted targets, which was supported by increased expression of HIF1A, PTGS2, and PPARG in AR-treated femora. Collectively, these findings suggest that AR promotes fracture healing by regulating osteogenic differentiation and bone remodeling through multi-target transcriptional networks. Full article

Mitochondria play a crucial role in cellular bioenergetics, signaling, and metabolism; yet, many fundamental mechanisms such as the proton transfer along the membranes, the link between membrane curvature and oxidative phosphorylation, and the nanoscale organization of enzyme supercomplexes remain poorly understood due to the limitations of classical biochemical approaches. This review addresses this gap by systematically analyzing the contemporary physical methods used to investigate the mitochondrial structure and function from the micro to nano scale. It covers advanced fluorescence and super-resolution microscopy, electron and volume electron microscopy, and scanning probe techniques, as well as cryo-electron tomography for resolving supramolecular assemblies in near-native conditions. The review highlights the applications of the modern fluorescent probes, expansion and phase microscopy, and machine-learning-based image analysis for a quantitative assessment of the mitochondrial morphology, membrane potential, and dynamics in living cells and tissues. Complementary spectroscopic and scattering methods, including Raman spectroscopy, NMR, and X-ray and neutron scattering, are discussed as tools for probing the redox state, metabolite composition, and membrane organization. Emphasis is placed on integrating high-resolution experimental data with advanced computational frameworks to test competing models of mitochondrial function and pathology, and to guide the development of biomimetic and biomedical technologies. Full article

The implant–abutment connection (IAC) is a critical determinant of the mechanical and biological performance of dental implants. Connection design and insertion torque may influence fatigue resistance, micromovement, and microgap formation, thereby affecting long-term implant success. This in vitro study evaluated a novel conical implant–abutment connection under controlled mechanical loading conditions. Methods: A sequential in vitro protocol was applied. Mechanical testing was conducted according to ISO 14801:2016 and included static and cyclic loading tests of the KS implant system inserted at two different torque values (35 Ncm and 70 Ncm). High-resolution micro-computed tomography (micro-CT) was performed after mechanical loading to evaluate implant–abutment interface integrity, microstructural alterations, and microgap behavior. Results: Static and cyclic loading tests revealed no observable differences between implants inserted at 35 Ncm and 70 Ncm, with all specimens completing the loading protocols without mechanical failure. Micro-CT analysis showed no evidence of microfractures, permanent deformation, or clinically relevant alterations at the implant–abutment interface. A stable and well-sealed connection was observed for both torque values following mechanical loading. Conclusions: Within the limitations of this in vitro study, the investigated conical implant–abutment connection demonstrated stable mechanical performance and preserved interface integrity after static and cyclic loading, regardless of whether implants were placed at 35 Ncm or 70 Ncm. These findings indicate that, under the present experimental conditions, both torque levels were associated with comparable structural integrity and mechanical stability of the investigated implant–abutment connection. This study should be interpreted as a preliminary experimental investigation, designed to provide descriptive and mechanistic insights rather than statistically powered comparative conclusions. Further long-term clinical trials are required to confirm these preliminary results. Full article

The inevitable pore defects generated in the preparation process have a great impact on the mechanical properties of the ceramic matrix composites. However, the pore defects on the composites were ignored to a large extent in models established in the previous research. In this study, in order to investigate the bending damage behaviors of SiC_f/SiC (SiC fiber-reinforced SiC matrix) angle-interlock (2.5D) woven composites prepared by the precursor immersion pyrolysis (PIP) method, a more precise full-scale model of composites was established by finite element (FE) method with taking into account of random pore defects generated by Monte Carlo algorithm. Micro-computed tomography (Micro-CT) was employed to acquire the statistical data of the yarns and pores of SiC_f/SiC 2.5D woven composites. A bending test was conducted to study the damage behaviors of the composite and compared with the prediction of the FE model. The result shows that the proposed model with random pores can predict the mechanical damage behavior of SiC_f/SiC 2.5D woven composites effectively under three-point bending. The simulated bending strength shows a good agreement with the experimental data, with a relative error of approximately 4.6%. Full article

This study investigates whether detector materials with an effective atomic number (Z_eff), density, and light output higher than cesium iodide (CsI) could provide images of better quality in dual-energy cone beam computed tomography (CBCT) breast examinations. Seven different detector material configurations were applied in a simulated micro-CBCT system using GATE v.9.2.1 (GEANT4 application for tomographic emission). Four breast phantoms, containing microcalcifications of Type I and Type II, were imaged. Planar images and tomographic data were analyzed. Microcalcification CNRs (contrast-to-noise ratios) were calculated for each configuration. CZT (cadmium zinc telluride) and GAGG (gadolinium aluminum gallium garnet) materials show a 3–17% increase in relative HAp (hydroxyapatite)-CNR values towards CsI. Full article

This study focuses on porous polyimide (PPI) lubricating materials for high-speed aerospace bearings. Based on their real microstructure, three-dimensional digital model reconstruction and mesoscale seepage characteristics were investigated. First, a sequence of two-dimensional slice images of PPI was obtained using micro-focus X-ray computed tomography (CT). Through image filtering, threshold segmentation, and three-dimensional reconstruction, a highly faithful digital model of the pore structure was constructed, and a quantified pore-network model was further extracted. Second, a multiple-relaxation-time lattice Boltzmann model based on the D3Q27 discrete scheme was established, and its accuracy and stability in complex boundaries and pressure-driven flows were verified using classic benchmark cases. Subsequently, the validated numerical model was applied to the reconstructed PPI pore structure to simulate and systematically analyze the single-phase seepage behavior of lubricating oil. The results show that the lubricant seepage exhibits a strong “preferential flow path” effect, with most of the flow transported through a small number of large-size throats. A clear quantitative relationship exists between the microscopic flow field structure—including velocity distribution, flow paths, and pressure gradient—and the pore-topology features, such as throat-size distribution, connectivity, and tortuosity. This verifies the mesoscale mechanism that “structure governs flow.” The complete technical chain established in this work—“real-structure reconstruction–numerical model validation–seepage mechanism analysis”—provides a reliable theoretical and numerical tool for gaining deeper insight into the lubricant transport behavior in porous polyimide and offers guidance for the microstructural design and optimization of this material. Full article

Background: Joint inflammation is significantly connected with progressive joint deterioration, potentially increasing the incidence of persistent major clinical challenges and global disability. Nutrient-based preventive strategies have been explored to investigate the interventive efficacy of the proposed prescribed formula for joint inflammation. However, the synergistic ameliorative effects of the nutritional formula should be evaluated to investigate its impact on joint inflammation. Methods: A prescribed formula including turmeric (T), N-acetylglucosamine (G), enzymatically hydrolyzed bone powder (E), and undenatured type II collagen (U) was comprehensively evaluated for its synergistic effects on joint inflammation and the underlying mechanisms. A rat model established using the Hulth method was used to evaluate the interventive effects in vivo. Moreover, in vitro analysis using the murine chondrogenic cell line ATDC5 was performed to validate the intervention and its mechanism of action. Results: The prescribed formula was shown to synergistically reduce levels of inflammation-related cytokines, reduce oxidative stress, and enhance bone metabolism to promote joint regeneration. Micro-Computed Tomography (Micro-CT) analysis revealed restoration of joint architecture and ameliorated physiological status upon formula intervention. In vitro analysis further validated the synergistic alleviation of inflammation and oxidation, as well as reductions in MMP13 and CTX-1 levels, which implies that modulating bone metabolism alleviates the deterioration and inflammation of joint architecture. Conclusions: The synergistic formula in this study achieves synchronous modulation of several core pathological pathways, yielding synergistic modulation of joint inflammation. Nutrient-based interventions or preventive strategies show promising effects against joint inflammation and progressive mechanistic deterioration. Full article

The placement technique of resin composites may significantly influence marginal integrity, wear resistance, and operative efficiency. This in vitro study evaluated the influence of different placement techniques for a bulk-fill resin composite on marginal integrity, wear behavior, and application time. Standardized Class I cavities were prepared in extracted human molars and restored using the same bulk-fill composite (Filtek One Bulk Fill, 3M, USA) applied with four techniques: incremental placement, incremental placement with a modeling liquid (GC Modeling Liquid, GC Corp., Tokyo, Japan), bulk placement, and the stamp technique. Application time was recorded in seconds. All specimens underwent combined mechanical and thermal aging (SD Mechatronik, Germany). Marginal integrity was assessed three-dimensionally using micro-computed tomography, while surface wear was quantified through computer-based digital analysis with OraCheck software (Dentsply Sirona, Germany). Bulk placement exhibited significantly higher microleakage scores than the other techniques while demonstrating the shortest application time. Incremental placement, incremental placement with modeling liquid, and the stamp technique showed comparable microleakage results (p > 0.05). Although the use of modeling liquid did not increase microleakage, it resulted in significantly greater wear. Placement technique significantly influences marginal integrity, wear behavior, and application time of bulk-fill composite restorations. Full article

Background/Objectives: Cells derived from direct chemical reprogramming into osteoblasts represent a promising source for bone regeneration, but the efficiency needs improvement. Here, we systematically evaluated whether the natural compound psoralen (Psr) could enhance this process and explored its therapeutic potential and mechanism of action. Methods: Mouse embryonic fibroblasts (MEFs) were treated with a cocktail of forskolin and phenamil (FP), supplemented with Psr. In vitro differentiation was assessed by alkaline phosphatase and Alizarin Red S staining, reverse transcription quantitative PCR, immunofluorescence and Western blot. The bone-regenerative potential of the derived chemically induced osteoblast-like cells (ciOBs) was evaluated in critical-sized calvarial defects, femoral cortical defects and a subcutaneous ectopic implantation model, using micro-computed tomography and histology. Mechanistic insights of Psr were gained by analyzing the adenylyl cyclase 9 (ADCY9)/cyclic adenosine monophosphate (cAMP)/protein kinase A (PKA)/cAMP response element-binding protein (CREB) axis using inhibitor SQ22536. Results: Psr acted synergistically with the FP cocktail to drive efficient osteogenic reprogramming of MEFs. At an optimal concentration of 25 μM, Psr enabled the most robust induction of early osteogenic markers and generation of mature, mineralizing ciOBs in vitro. In vivo, FP + Psr-induced ciOBs repaired critical-sized calvarial and femoral cortical defects and generated substantial, vascularized bone tissue in ectopic sites. Mechanistically, Psr co-treatment potently activated the ADCY9/cAMP/PKA/CREB pathway, and pharmacological inhibition of this pathway completely abolished the pro-osteogenic effects of Psr. Conclusions: Psr acts as a potent synergistic enhancer of direct chemical reprogramming, generating functional osteoblast-like cells with robust bone-regenerative capacity via activation of the ADCY9/cAMP/PKA/CREB pathway. Full article