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In skeleton‐based action recognition, the graph convolutional network (GCN) has achieved great success. Modelling skeleton data in a suitable spatial‐temporal way and designing the adjacency matrix are crucial aspects for GCN‐based methods to capture joint relationships. In this study, we propose the spatial‐temporal slowfast graph convolutional network (STSF‐GCN) and design the adjacency matrices for the skeleton data graphs in STSF‐GCN. STSF‐GCN contains two pathways: (1) the fast pathway is in a high frame rate, and joints of adjacent frames are unified to build 'small' spatial‐temporal graphs. A new spatial‐temporal adjacency matrix is proposed for these 'small' spatial‐temporal graphs. Ablation studies verify the effectiveness of the proposed adjacency matrix. (2) The slow pathway is in a low frame rate, and joints from all frames are unified to build one 'big' spatial‐temporal graph. The adjacency matrix for the 'big' spatial‐temporal graph is obtained by computing self‐attention coefficients of each joint. Finally, outputs from two pathways are fused to predict the action category. STSF‐GCN can efficiently capture both long‐range and short‐range spatial‐temporal joint relationships. On three datasets for skeleton‐based action recognition, STSF‐GCN can achieve state‐of‐the‐art performance with much less computational cost. [ABSTRACT FROM AUTHOR]

In the Yangtze River Delta, natural lacquer has been used as coating and adhesive since the Neolithic. At Jingtoushan Neolithic site, the earliest, deepest buried prehistoric shell mound site discovered in China's coastal areas, where stratigraphic age lies between 7,800–8,300 cal BP, we discovered the earliest lacquerwares of China. The relics are a piece of dowelled wood and an oblate wooden stick. The black coatings on the two relics were studied by using non‐destructive infrared analysis, pyrolysis‐gas chromatography/mass spectrometry (Py‐GC/MS), and enzyme‐linked immune sorbent assay (ELISA), and the analysis determined that black coating on the two relics is natural lacquer. This discovery refreshes the history of natural lacquer used by humans in the Yangtze River Delta to more than 8,000 years ago and also complements the history of organic coatings used during the Neolithic period in China. [ABSTRACT FROM AUTHOR]

Objective: This study aimed to investigate how mechanical force affects the proliferation of human periodontal ligament stem cells (hPDLSCs). Methods: CCK‐8 assays and staining of ki67 were performed to evaluate hPDLSCs proliferation. qRT‐PCR, ELISA, or Western blot analysis were used to measure the expression levels of interleukin (IL)‐6, miR‐31 host gene (MIR31HG), DNA methyltransferase 1 (DNMT1), and DNA methyltransferase 3B (DNMT3B). Dual‐luciferase reporter assays and chromatin immunoprecipitation (ChIP) assays were conducted to determine whether MIR31HG was targeted by DNMT1 and DNMT3B. MassARRAY mass spectrometry was used to quantify DNA methylation levels of the MIR31HG promoter. Results: Mechanical force inhibited hPDLSCs proliferation with the downregulation of MIR31HG and upregulation of IL‐6, DNMT1 and DNMT3B. Knockdown of MIR31HG suppressed hPDLSCs proliferation, and knockdown of DNMT1 or DNMT3B reversed mechanical force‐induced downregulation of MIR31HG. Dual‐luciferase and ChIP assays revealed DNMT1 and DNMT3B bound MIR31HG promoter in the region 1,015 bp upstream of the transcriptional start site. Treatment with 5'‐aca‐2'‐deoxycytidine downregulated DNA methylation level in MIR31HG gene promoter, while mechanical force promoted the methylation of MIR31HG gene promoter. Conclusions: These findings elucidated how mechanical force affects proliferation via MIR31HG in hPDLSCs, providing clues for possible MIR31HG‐based orthodontic therapeutic approaches. [ABSTRACT FROM AUTHOR]

Circular RNAs(circRNAs) are a large family of RNAs shaping covalently closed ring-like molecules and have become a hotspot with thousands of newly published studies. Stem cells are undifferentiated cells and have great potential in medical treatment due to their self-renewal ability and differentiation capacity. Abundant researches have unveiled that circRNAs have unique expression profile during the differentiation of stem cells and could serve as promising biomarkers of these cells. There are key circRNAs relevant to the differentiation, proliferation, and apoptosis of stem cells with certain mechanisms such as sponging miRNAs, interacting with proteins, and interfering mRNA translation. Moreover, several circRNAs have joined in the interplay between stem cells and lymphocytes. Our review will shed lights on the emerging roles of circRNAs in regulating the fate of diverse stem cells. [ABSTRACT FROM AUTHOR]

Objective: Secondary alveolar bone grafting is an essential part in the treatment of alveolar cleft deformity. Autologous iliac bone is the most favorable grafting source. However, the factors regulating postoperative bone formation are unclear. Investigations are needed to found whether the alveolar bone niche and bone marrow mesenchymal stem cells (BMSCs) derived from the jaw bone (BMSCs‐J) affected the osteogenesis of BMSCs from the ilium (BMSCs‐I). Materials and Methods: The effect of BMSCs‐J on BMSCs‐I was investigated using a co‐culture model. The exosomes were purified by sequential centrifugation. The osteoblastic differentiation of BMSCs was analyzed in vitro and in vivo. Results: Co‐culture with BMSCs‐J increased the alkaline phosphatase (ALP) activity, Alizarin Red S (ARS) staining, and osteogenic gene expression in BMSCs‐I. Transmission electron microscopy and nanoparticle tracking analysis verified the presence of exosomes in the culture supernatants of BMSCs. Exosomes secreted by BMSCs‐J enhanced the ALP activity, ARS staining, osteogenic gene expression of BMSCs‐I in vitro, and new bone formation in vivo. Blocking the secretion of exosomes using siRNA for Rab27a inhibited the effect of BMSCs‐J. Conclusion: Exosomes played a role in the interaction between BMSCs‐J and BMSCs‐I, thereby leading to the enhanced osteogenic capacity of BMSCs‐I and bone formation. [ABSTRACT FROM AUTHOR]