保密通信作为物联网安全的一项核心技术近些年受到了广泛关注。无人机(UAV)由于其高机动和灵活部署等特性,被认为是提高物联网通信安全的有力手段。针对当前物联网中UAV辅助保密通信频谱利用率问题,研究了UAV和地面设备到设备(Device-to...保密通信作为物联网安全的一项核心技术近些年受到了广泛关注。无人机(UAV)由于其高机动和灵活部署等特性,被认为是提高物联网通信安全的有力手段。针对当前物联网中UAV辅助保密通信频谱利用率问题,研究了UAV和地面设备到设备(Device-to-Device, D2D)通信系统频谱共享的系统保密容量最大化,提出了一种基于块坐标下降(Block Coordinate Descent, BCD)法的频谱共享算法,该算法通过联合优化系统中发送方(UAV和地面设备对)的传输功率和无人机轨迹,在确保地面设备对和UAV能够共存的情况下最大化接收方的保密容量。具体来说,该算法通过差分凸规划(Difference of Two Convex Functions, DC)方法优化固定轨迹下的系统功率,利用连续凸优化方法解决给定发射功率的UAV轨迹优化问题。仿真结果表明,所提方法在多种参数配置下都能有效提高系统的保密容量,并且和其他算法相比有更低的功率消耗。展开更多
BACKGROUND Colorectal cancer stem cells(CCSCs)are heterogeneous cells that can self-renew and undergo multidirectional differentiation in colorectal cancer(CRC)patients.CCSCs are generally accepted to be important sou...BACKGROUND Colorectal cancer stem cells(CCSCs)are heterogeneous cells that can self-renew and undergo multidirectional differentiation in colorectal cancer(CRC)patients.CCSCs are generally accepted to be important sources of CRC and are responsible for the progression,metastasis,and therapeutic resistance of CRC.Therefore,targeting this specific subpopulation has been recognized as a promising strategy for overcoming CRC.AIM To investigate the effect of VX-509 on CCSCs and elucidate the underlying mechanism.METHODS CCSCs were enriched from CRC cell lines by in conditioned serum-free medium.Western blot,Aldefluor,transwell and tumorigenesis assays were performed to verify the phenotypic characteristics of the CCSCs.The anticancer efficacy of VX-509 was assessed in HCT116 CCSCs and HT29 CCSCs by performing cell viability analysis,colony formation,sphere formation,flow cytometry,and western blotting assessments in vitro and tumor growth,immunohistochemistry and immunofluorescence assessments in vivo.RESULTS Compared with parental cells,sphere cells derived from HCT116 and HT29 cells presented increased expression of stem cell transcription factors and stem cell markers and were more potent at promoting migration and tumori-genesis,demonstrating that the CRC sphere cells displayed CSC features.VX-509 inhibited the tumor malignant biological behavior of CRC-stem-like cells,as indicated by their proliferation,migration and clonality in vitro,and suppressed the tumor of CCSC-derived xenograft tumors in vivo.Besides,VX-509 suppressed the CSC character-istics of CRC-stem-like cells and inhibited the progression of epithelial-mesenchymal transition(EMT)signaling in vitro.Nodal was identified as the regulatory factor of VX-509 on CRC stem-like cells through analyses of differen-tially expressed genes and CSC-related database information.VX-509 markedly downregulated the expression of Nodal and its downstream phosphorylated Smad2/3 to inhibit EMT progression.Moreover,VX-509 reversed the dedifferentiation of CCSCs and inhibited the progression of EMT induced by Nodal overexpression.CONCLUSION VX-509 prevents the EMT process in CCSCs by inhibiting the transcription and protein expression of Nodal,and inhibits the dedifferentiated self-renewal of CCSCs.展开更多
文摘保密通信作为物联网安全的一项核心技术近些年受到了广泛关注。无人机(UAV)由于其高机动和灵活部署等特性,被认为是提高物联网通信安全的有力手段。针对当前物联网中UAV辅助保密通信频谱利用率问题,研究了UAV和地面设备到设备(Device-to-Device, D2D)通信系统频谱共享的系统保密容量最大化,提出了一种基于块坐标下降(Block Coordinate Descent, BCD)法的频谱共享算法,该算法通过联合优化系统中发送方(UAV和地面设备对)的传输功率和无人机轨迹,在确保地面设备对和UAV能够共存的情况下最大化接收方的保密容量。具体来说,该算法通过差分凸规划(Difference of Two Convex Functions, DC)方法优化固定轨迹下的系统功率,利用连续凸优化方法解决给定发射功率的UAV轨迹优化问题。仿真结果表明,所提方法在多种参数配置下都能有效提高系统的保密容量,并且和其他算法相比有更低的功率消耗。
基金National Natural Science Foundation of China,No.82074298Chengdu Science and Technology Bureau Project,No.2021-YF05-01726-SN“Xinglin Scholars”Research Promotion Program of Chengdu University of Traditional Chinese Medicine,No.QJRC2022007.
文摘BACKGROUND Colorectal cancer stem cells(CCSCs)are heterogeneous cells that can self-renew and undergo multidirectional differentiation in colorectal cancer(CRC)patients.CCSCs are generally accepted to be important sources of CRC and are responsible for the progression,metastasis,and therapeutic resistance of CRC.Therefore,targeting this specific subpopulation has been recognized as a promising strategy for overcoming CRC.AIM To investigate the effect of VX-509 on CCSCs and elucidate the underlying mechanism.METHODS CCSCs were enriched from CRC cell lines by in conditioned serum-free medium.Western blot,Aldefluor,transwell and tumorigenesis assays were performed to verify the phenotypic characteristics of the CCSCs.The anticancer efficacy of VX-509 was assessed in HCT116 CCSCs and HT29 CCSCs by performing cell viability analysis,colony formation,sphere formation,flow cytometry,and western blotting assessments in vitro and tumor growth,immunohistochemistry and immunofluorescence assessments in vivo.RESULTS Compared with parental cells,sphere cells derived from HCT116 and HT29 cells presented increased expression of stem cell transcription factors and stem cell markers and were more potent at promoting migration and tumori-genesis,demonstrating that the CRC sphere cells displayed CSC features.VX-509 inhibited the tumor malignant biological behavior of CRC-stem-like cells,as indicated by their proliferation,migration and clonality in vitro,and suppressed the tumor of CCSC-derived xenograft tumors in vivo.Besides,VX-509 suppressed the CSC character-istics of CRC-stem-like cells and inhibited the progression of epithelial-mesenchymal transition(EMT)signaling in vitro.Nodal was identified as the regulatory factor of VX-509 on CRC stem-like cells through analyses of differen-tially expressed genes and CSC-related database information.VX-509 markedly downregulated the expression of Nodal and its downstream phosphorylated Smad2/3 to inhibit EMT progression.Moreover,VX-509 reversed the dedifferentiation of CCSCs and inhibited the progression of EMT induced by Nodal overexpression.CONCLUSION VX-509 prevents the EMT process in CCSCs by inhibiting the transcription and protein expression of Nodal,and inhibits the dedifferentiated self-renewal of CCSCs.
