PDGFRαreporter activity identifies periosteal progenitor cells critical for bone formation and fracture repair

The outer coverings of the skeleton,which is also known as the periosteum,are arranged in concentric layers and act as a reservoir for tissue-specific bone progenitors.The cellular heterogeneity within this tissue depot is being increasingly recognized.Here,inducible PDGFRαreporter animals were found to mark a population of cells within the periosteum that act as a stem cell reservoir for periosteal appositional bone formation and fracture repair.During these processes,PDGFRαreporter^(+)progenitors give rise to Nestin+periosteal cells before becoming osteoblasts and osteocytes.The diphtheria toxin-mediated ablation of PDGFRαreporter^(+)cells led to deficits in cortical bone formation during homeostasis and a diminutive hard callus during fracture repair.After ossicle transplantation,both mouse PDGFRαreporter^(+)periosteal cells and human Pdgfrα+periosteal progenitors expand,ossify,and recruit marrow to a greater extent than their counterpart periosteal cells,whereas PDGFRαreporter^(−)periosteal cells exhibit a predisposition to chondrogenesis in vitro.Total RNA sequencing identified enrichment of the secreted factors Fermt3 and Ptpn6 within PDGFRαreporter^(+)periosteal cells,which partly underlie the osteoblastogenic features of this cell population.

Comparison of skeletal and soft tissue pericytes identifies CXCR4+ bone forming mural cells in human tissues

Human osteogenic progenitors are not precisely defined,being primarily studied as heterogeneous multipotent cell populations and termed mesenchymal stem cells(MSCs).Notably,select human pericytes can develop into bone-forming osteoblasts.Here,we sought to define the differentiation potential of CD146 f human pericytes from skeletal and soft tissue sources,with the underlying goal of defining cell surface markers that typify an osteoblastogenic pericyte.CD146+CD31~CD45_pericytes were derived by fluorescence-activated cell sorting from human periosteum,adipose,or dermal tissue.Periosteal CD146+CD31—CD45 cells retained canonical features of pericytes/MSC.Periosteal pericytes demonstrated a striking tendency to undergo osteoblastogenesis in vitro and skeletogenesis in vivo,while soft tissue pericytes did not readily.Transcriptome analysis revealed higher CXCR4 signaling among periosteal pericytes in comparison to their soft tissue counterparts,and CXCR4 chemical inhibition abrogated ectopic ossification by periosteal pericytes.Conversely,enrichment of CXCR4+pericytes or stromal cells identified an osteoblastic/non-adipocytic precursor cell.In sum,human skeletal and soft tissue pericytes differ in their basal abilities to form bone.Diversity exists in soft tissue pericytes,however,and CXCR4+pericytes represent an osteoblastogenic,non-adipocytic cell precursor.Indeed,enrichment for CXCR4-expressing stromal cells is a potential new tactic for skeletal tissue engineering.

A Preprocessing Method for Gait Recognition

The results of image preprocessing may directly affect gait feature extraction in the area of gait recognition. Due to the influence of light, shelter and other external factors of gait image, some problems such as loss of information,image shadows, and improper threshold of image preprocessing may occur. In order to solve these problems, an image preprocessing method of gait recognition is proposed. Firstly, background image is extracted by background modeling, secondly, the target profile is extracted by the direct difference method; thirdly, the shadow elimination based on the HSV color model is carried out on the target profile map; Finally, the complete target profile is obtained by threshold segmentation. Experimental results on CASIA_A database demonstrate that this proposed method is quite effective on both target profile extraction and proportion comparison with the real area.

幻数团簇丝氨酸八聚体:结构和手性特征

自从2001年丝氨酸八聚体第一次在质谱中被观察到,这种奇特的幻数团簇就受到研究者们的广泛关注。丝氨酸八聚体具有显著的同手性优势,而且它的手性能够通过对映选择性取代反应传递给其他分子。一些研究者提出这种丝氨酸八聚体的同手性优势很可能与生命的同手性起源相关。本文综述了丝氨酸八聚体的产生、结构和手性特征等方面的研究结果和进展,其中包括运用串联质谱(MS/MS),气相H/D交换,离子淌度,红外解离光谱等多种实验方法以及理论计算对丝氨酸八聚体及含有取代单元的八聚体的相关研究。这些结果逐步地揭示了丝氨酸八聚体的结构特点和性质,进一步加深了人们对其在手性识别和手性传递方面的作用的理解。然而,由于体系的复杂性,真正地理解其结构、同手性选择性的原因以及其在生物分子同手性起源中的作用仍是一个非常具有挑战性的问题。

Beyond fundamental resonance mode:high-order multi-band ALN PMUT for in vivo photoacoustic imaging

This paper reports on an aluminum nitride(AlN)piezoelectric micromachined ultrasound transducer(PMUT)array for photoacoustic(PA)imaging,where the high-order resonance modes of the PMUT are utilized to improve imaging resolution.A flexural vibration mode(FVM)PMUT is fabricated and applied in a photoacoustic imaging(PAI)system.Specifically,the microelectromechanical system(MEMS)-based PMUT is suitable for PA endoscopic imaging of blood vessels and bronchi due to its miniature size and high sensitivity.More importantly,AlN is a nontoxic material,which makes it harmless for biomedical applications.In the PAI system,the AlN PMUT array is used to detect PA signals,and the acousto–mechanical response is designed and optimized at the PMUT’s fundamental resonance.In this work,we focus on the high-order resonance performance of the PMUT PAI beyond the fundamental resonance.The acoustic and electrical responses of the PMUT’s high-order resonance modes are characterized and analyzed.The fundamental and three high-order resonance bandwidths are 2.2,8.8,18.5,and 48.2 kHz.Compared with the resolution at the fundamental resonance mode,the resolutions at third-and fourth-order resonance modes increase by 38.7%and 76.9%in a phantom experiment.The high-order resonance modes of the AlN PMUT sensor array provide higher central frequency and wider bandwidth for PA signal detection,which increase the resolution of PAI compared to the PMUT working at the fundamental resonance mode.

A giant step forward: chimeric antigen receptor T-cell therapy for lymphoma

The combination of the immunotherapy(i.e.,the use of monoclonal antibodies)and the conventional chemotherapy increases the long-term survival of patients with lymphoma.However,for patients with relapsed or treatment-resistant lymphoma,a novel treatment approach is urgently needed.Chimeric antigen receptor T(CAR-T)cells were introduced as a treatment for these patients.Based on recent clinical data,approximately 50%of patients with relapsed or refractory B-cell lymphoma achieved complete remission after receiving the CD19 CAR-T cell therapy.Moreover,clinical data revealed that some patients remained in remission for more than two years after the CAR-T cell therapy.Other than the CD19-targeted CAR-T,the novel target antigens,such as CD20,CD22,CD30,and CD37,which were greatly expressed on lymphoma cells,were studied under preclinical and clinical evaluations for use in the treatment of lymphoma.Nonetheless,the CAR-T therapy was usually associated with potentially lethal adverse effects,such as the cytokine release syndrome and the neurotoxicity.Therefore,optimizing the structure of CAR,creating new drugs,and combining CAR-T cell therapy with stem cell transplantation are potential solutions to increase the effectiveness of treatment and reduce the toxicity in patients with lymphoma after the CAR-T cell therapy.