Tracing PRX1+cells during molar formation and periodontal ligament reconstruction

Neural crest-derived mesenchymal stem cells(MSCs)are known to play an essential function during tooth and skeletal development.PRX1+cells constitute an important MSC subtype that is implicated in osteogenesis.However,their potential function in tooth development and regeneration remains elusive.In the present study,we first assessed the cell fate of PRX1+cells during molar development and periodontal ligament(PDL)formation in mice.Furthermore,single-cell RNA sequencing analysis was performed to study the distribution of PRX1+cells in PDL cells.The behavior of PRX1+cells during PDL reconstruction was investigated using an allogeneic transplanted tooth model.Although PRX1+cells are spatial specific and can differentiate into almost all types of mesenchymal cells in first molars,their distribution in third molars is highly limited.The PDL formation is associated with a high number of PRX1+cells;during transplanted teeth PDL reconstruction,PRX1+cells from the recipient alveolar bone participate in angiogenesis as pericytes.Overall,PRX1+cells are a key subtype of dental MSCs involved in the formation of mouse molar and PDL and participate in angiogenesis as pericytes during PDL reconstruction after tooth transplantation.

Primary cilia support cartilage regeneration after injury

In growing children,growth plate cartilage has limited self-repair ability upon fracture injury always leading to limb growth arrest.Interestingly,one type of fracture injuries within the growth plate achieve amazing self-healing,however,the mechanism is unclear.Using this type of fracture mouse model,we discovered the activation of Hedgehog(Hh)signaling in the injured growth plate,which could activate chondrocytes in growth plate and promote cartilage repair.

Research on Surface Roughness of Supersonic Vibration Auxiliary Side Milling for Titanium Alloy

The processed surface contour shape is extracted with the finite element simulation software.The difference value of contour shape change is used as the parameters of balancing surface roughness to construct finite element model of supersonic vibration milling in cutting stability domain.The surface roughness trial scheme is designed in the orthogonal test design method to analyze the surface roughness test result in the response surface methodology.The surface roughness prediction model is established and optimized.Finally,the surface roughness finite element simulation prediction model is verified by experiments.The research results show that,compared with the experiment results,the error range of the finite element simulation model is 27.5%–30.9%,and the error range of the empirical model obtained by the response surface method is between 4.4%and 12.3%.So,the model in this paper is accurate and will provide the theoretical basis for the optimization study of the auxiliary milling process of supersonic vibration.

Role of pre-vertical compression in deformation behavior of Mg alloy AZ31B during super-high reduction hot rolling process

Mg alloy AZ31 B plates were processed by hot rolling with different thickness reductions per pass and prevertical compression followed by super-high reduction hot rolling（PVCR）, respectively. Microstructure evolution, rolling formability variation and mechanical responses were investigated. As reduction per pass increased, the number of shear bands deflecting toward rolling direction increased, resulting in easy crack initiation in and around the bands. With increasing reduction per pass up to 80%, twinning and twinning-induced dynamic recrystallization（DRX） dominated the deformation of the edge material at350℃, resulting in local recrystallization with coarse grains and further largest edge-crack degree. Preinduced {101^-2} tensile twins by pre-vertical compression（PVC） increased number density of nucleation sites for dynamic recrystallization during the subsequent severe rolling, which enhanced the dominant role of continuous dynamic recrystallization. Designed PVCR-b was proved to be a relatively effective method to improve rolling formability of rolled Mg alloy AZ31 B plates. With this method, mean grain size of AZ31 B plate was significantly refined from ~600 mm to ~14.1 mm and more homogeneous grain size distribution along transverse direction（TD） was achieved. In addition, basal texture intensity was greatly weakened. As a result, tensile anisotropy was distinctly decreased and fracture elongation increased dramatically.