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Alveolar bone (AB) remodeling, including formation and absorption, is the foundation of orthodontic tooth movement (OTM). However, the sources and mechanisms underlying new bone formation remain unclear. Therefore, we aimed to understand the potential mechanism of bone formation during OTM, focusing on the leptin receptor+ (Lepr+) osteogenitors and periodontal ligament cells (PDLCs). We demonstrated that Lepr+ cells activated by force-induced PDLC apoptosis served as distinct osteoprogenitors during orthodontic bone regeneration. We investigated bone formation both in vivo and in vitro. Single-cell RNA sequencing analysis and lineage tracing demonstrated that Lepr represents a subcluster of stem cells that are activated and differentiate into osteoblasts during OTM. Targeted ablation of Lepr+ cells in a mouse model disrupted orthodontic force–guided bone regeneration. Furthermore, apoptosis and sequential fluorescent labeling assays revealed that the apoptosis of PDLCs preceded new bone deposition. We found that PDL stem cell–derived apoptotic vesicles activated Lepr+ cells in vitro. Following apoptosis inhibition, orthodontic force–activated osteoprogenitors and osteogenesis were significantly downregulated. Notably, we found that bone formation occurred on the compression side during OTM; this has been first reported here. To conclude, we found a potential mechanism of bone formation during OTM that may provide new insights into AB regeneration. [ABSTRACT FROM AUTHOR]

In this study, a closed-cell aluminum foam was filled into the interspaces of a sandwich panel with corrugated cores to form a composite structure. The novel structure is expected to have enhanced foam-filled cores with high specific strength and energy absorption capacity. An out-of-plane compressive load under low-velocity impact was experimentally and numerically carried out on both the empty and foam-filled sandwich panels as well as on the aluminum foam. It is found that the empty corrugated sandwich panel has poor energy absorption capacity due to the core member buckling compared to that of the aluminum foam. However, by the filling of the aluminum foam, the impact load resistance of the corrugated panel was increased dramatically. The loading-time response of the foam-filled panel performs a plateau region like the aluminum foam, which has been proved to be an excellent energy absorption material. Numerical results demonstrated that the aluminum foam filling can decrease the corrugated core member defects sensitivity and increase its stability dramatically. The plastic energy dissipation of the core member for the foam-filled panel is much higher than that of the empty one due to the reduced buckling wavelength caused by the aluminum foam filling. [ABSTRACT FROM AUTHOR]

With samples made of composite prepared by adding nickel powder (NP) as a functional filler into cement based material, experiments are carried out to study the piezoresistivity of this NP filled cement based composite (NPCC) under single compressive loading to destruction and within elastic regime. Experimental results indicate that the electrical resistivity of NP filled cement based composite exhibits a three-stage variation trend of fast decrease, slow decrease and steady increase as compressive stress and strain increase under single compressive loading to destruction, and its fractional change goes up to 79·28% maximum. The electrical resistivity of the piezoresistive NPCC decreases 74·67% within elastic regime, and the sensitivity of this composite to compressive stress, compressive strain and transverse tensile strain goes up to 0·158 MPa-1, 1228·2 and 7580 maximum respectively. It therefore can be concluded that the developed piezoresistive NPCC has high sensitivity to stress/strain. [ABSTRACT FROM AUTHOR]

Tumor necrosis factor-alpha-converting enzyme (TACE) is a metalloprotease which can shed several cytokines from the cell membrane, including receptor activator of NF-kappaB ligand (RANKL). This study aimed to investigate the hypothesis that TACE would be elevated in the gingival crevicular fluid (GCF) of persons with periodontitis. Total TACE amounts in GCF were higher in persons with chronic and aggressive periodontitis than in those with gingivitis or in healthy persons. TACE concentrations in GCF were higher in persons with chronic and aggressive periodontitis than in those with gingivitis, although not significantly higher than in healthy persons. Persons with chronic periodontitis receiving immunosuppressive treatment exhibited over 10-fold lower TACE levels than the other periodontitis groups. TACE was positively correlated with probing pocket depth, clinical attachment levels, and RANKL concentrations in GCF. In conclusion, the increased GCF TACE levels in persons with periodontitis and their positive correlation with RANKL may indicate an association of this enzyme with alveolar bone loss, and may warrant special attention in future therapeutic approaches. [ABSTRACT FROM AUTHOR]

Nanoparticles possess a wide range of exceptional properties applicable to biology and medicine. In particular, nanodiamonds (NDs) are being studied extensively because they possess unique characteristics that make them suitable as platforms for diagnostics and therapeutics. This carbon-based material (2–8 nm) is medically relevant because it unites several key properties necessary for clinical applications, such as stability and compatibility in biological environments, and scalability in production. Research by the Ho group and others has yielded ND particles with a variety of capabilities ranging from delivery of chemotherapeutic drugs to targeted labeling and uptake studies. In addition, encouraging new findings have demonstrated the ability for NDs to effectively treat chemoresistant tumors in vivo. In this review, we highlight the progress made toward bringing nanodiamonds from the bench to the bedside. [ABSTRACT FROM PUBLISHER]