The osteoclastic activity in apical distal region of molar mesial roots affects orthodontic tooth movement and root resorption in rats

The utilization of optimal orthodontic force is crucial to prevent undesirable side effects and ensure efficient tooth movement during orthodontic treatment.However,the sensitivity of existing detection techniques is not sufficient,and the criteria for evaluating optimal force have not been yet established.Here,by employing 3D finite element analysis methodology,we found that the apical distal region(A-D region)of mesial roots is particularly sensitive to orthodontic force in rats.Tartrate-resistant acidic phosphatase(TRAP)-positive osteoclasts began accumulating in the A-D region under the force of 40 grams(g),leading to alveolar bone resorption and tooth movement.When the force reached 80 g,TRAP-positive osteoclasts started appearing on the root surface in the A-D region.Additionally,micro-computed tomography revealed a significant root resorption at 80 g.Notably,the A-D region was identified as a major contributor to whole root resorption.It was determined that 40 g is the minimum effective force for tooth movement with minimal side effects according to the analysis of tooth movement,inclination,and hyalinization.These findings suggest that the A-D region with its changes on the root surface is an important consideration and sensitive indicator when evaluating orthodontic forces for a rat model.Collectively,our investigations into this region would aid in offering valuable implications for preventing and minimizing root resorption during patients’orthodontic treatment.

Low intensity near-infrared light promotes bone regeneration via circadian clock protein cryptochrome 1

Bone regeneration remains a great clinical challenge. Low intensity near-infrared(NIR) light showed strong potential to promote tissue regeneration, offering a promising strategy for bone defect regeneration. However, the effect and underlying mechanism of NIR on bone regeneration remain unclear. We demonstrated that bone regeneration in the rat skull defect model was significantly accelerated with low-intensity NIR stimulation. In vitro studies showed that NIR stimulation could promote the osteoblast differentiation in bone mesenchymal stem cells(BMSCs) and MC3T3-E1 cells, which was associated with increased ubiquitination of the core circadian clock protein Cryptochrome 1(CRY1) in the nucleus. We found that the reduction of CRY1 induced by NIR light activated the bone morphogenetic protein(BMP) signaling pathways, promoting SMAD1/5/9 phosphorylation and increasing the expression levels of Runx2 and Osterix. NIR light treatment may act through sodium voltage-gated channel Scn4a, which may be a potential responder of NIR light to accelerate bone regeneration. Together, these findings suggest that low-intensity NIR light may promote in situ bone regeneration in a CRY1-dependent manner, providing a novel, efficient and non-invasive strategy to promote bone regeneration for clinical bone defects.

Fe-Mn-sepiolite as an effective heterogeneous Fenton-like catalyst for the decolorization of reactive brilliant blue

A study of the decolorization of reactive brilliant blue in an aqueous solution using Fe-Mn-sepiolite as a heterogeneous Fenton-like catalyst has been performed. The Fourier transform infrared （FTIR） spectra of the catalyst showed bending vibrations of the Fe-O. The Xray diffraction （XRD） patterns of the catalyst showed characteristic diffraction peaks of α-Fe203, γ-Fe203 and MnO. A four factor central composite design （CCD） coupled with response surface methodology （RSM） was applied to evaluate and optimize the important variables （catalyst addition, hydrogen peroxide dosage, initial pH value and initial dye concentration）. When the reaction conditions were catalyst dosage = 0.4 g, [H202]= 0.3 mL, pH= 2.5, [reactive brilliant blue]o = 50mg·L-1, and volume of solution = 500 mL at room temperature, the decolorization efficiency of reactive brilliant blue was 91.98% within 60min. Moreover, the Fe-Mn-sepiolite catalyst had good stability for the degradation of reactive brilliant blue even after six cycles. Leaching of iron ions （ 〈 0.4 mg·L-l） was observed. The decoloring process was reactive brilliant blue specific via a redox reaction. The benzene ring and naphthalene ring were first oxidized to open ring; these were then oxidized to the alcohol and carboxylic acid. The reactive brilliant blue was decom- posed mainly by the attack of .OH radicals including surface-bound .OH radicals generated on the catalyst surface.

Enantioselective Synthesis of Optically Active Bis(β-hydroxy) Sulfones through Asymmetric Hydrogenation of Corresponding Ketones Catalyzed by a Chiral Cationic Ruthenium Diamine Catalyst

Chiral molecules containing sulfonyl and 1,5-diol moieties are useful synthetic blocks for various asymmetric transformations.A protocol has been developed for the enantioselective synthesis of optically active bis(β-hydroxy)sulfones catalyzed by a chiral cationic ruthenium diamine catalyst.A series of bis(β-hydroxy)sulfones have been obtained in excellent yields(up to 99%)with excellent enantioselectivities(up to 99%)as well as good diastereoselectivities(up to 99∶1).