无线信道建模对于理解、设计和优化无线通信系统具有重要意义,是无线通信领域中不可或缺的一部分。为了满足车联网(vehicle to everything,V2X)环境中的通信需求,研究空间中障碍物的分布对信道衰落特性的影响,本文提出了一种新的随机散...无线信道建模对于理解、设计和优化无线通信系统具有重要意义,是无线通信领域中不可或缺的一部分。为了满足车联网(vehicle to everything,V2X)环境中的通信需求,研究空间中障碍物的分布对信道衰落特性的影响,本文提出了一种新的随机散射簇生成算法,即通过把Matérn硬核点过程和泊松簇过程相结合来模拟真实V2X信道中的障碍物。在算法中,依据真实环境障碍物的方位设置散射簇的坐标位置,根据周围障碍物密度合理设置簇内散射点数量。利用传播图论进行仿真,考虑直射路径和单跳散射路径,基于信道冲激响应(channel impulse response,CIR)分别研究了功率延迟分布(power delay profile,PDP)和多普勒功率谱密度(Doppler power spectrum density,DPSD),并分析了不同移动轨迹下的均方根(root mean square,RMS)时延扩展的累计分布函数(cumulative distribution function,CDF),以及莱斯K因子的分布特性和角度功率谱(power angular spectrum,PAS)的分布。本文研究验证得到,所提出的模型有助于分析车辆-基础设施(vehicle to infrastructure,V2I)通信场景下的时域非平稳特性,为V2X通信系统的设计和优化提供了重要参考。展开更多
目的:观察高选择性钠-葡萄糖协同转运蛋白2抑制剂(SGLT2i)对2型糖尿病(T2DM)伴射血分数降低心衰(HFrEF)患者的治疗效果。方法:选取某院2023年1月—2024年1月收治的T2DM伴HFrEF患者86例为研究对象,采用随机数字表法分为观察组和对照组,...目的:观察高选择性钠-葡萄糖协同转运蛋白2抑制剂(SGLT2i)对2型糖尿病(T2DM)伴射血分数降低心衰(HFrEF)患者的治疗效果。方法:选取某院2023年1月—2024年1月收治的T2DM伴HFrEF患者86例为研究对象,采用随机数字表法分为观察组和对照组,各43例。对照组常规降糖和抗心衰治疗,观察组在对照组基础上联合SGLT2i治疗。比较2组血糖指标[空腹血糖(FPG)、餐后2 h血糖(2 h PBG)、糖化血红蛋白(HbA1c)]、血清心功能指标[N末端B型钠尿肽前体(NT-proBNP)、可溶性生长刺激表达基因2蛋白(sST2)]、左心功能指标[左心室射血分数(LVEF)、左心室舒张末期内径(LVEDD)、左心室收缩末期内径(LVESD)]及不良反应发生率。结果:治疗3个月后,观察组FPG[(6.91±1.45)mmol/L]、HbA1c[(6.72±1.40)%]水平低于对照组[(7.50±1.17)mmol/L、(7.25±1.17)%](P<0.05),2组2h PBG水平比较差异无统计学意义(P>0.05);观察组NT-proBNP[(1551.04±567.79)pg/mL]、sST2[(22.15±4.38)ng/mL]水平低于对照组[(1845.75±482.22)pg/mL、(25.79±6.34)ng/mL](P<0.05);观察组LVESD[(46.19±5.18)mm]、LVEDD[(52.02±5.12)mm]低于对照组[(48.58±5.29)mm、(54.89±5.98)mm],LVEF[(36.36±1.76)%]高于对照组[(35.49±2.15)%],差异均有统计学意义(P<0.05)。2组不良反应发生率比较差异无统计学意义(P>0.05)。结论:SGLT2i对T2DM伴HFrEF治疗效果良好,可有效降低患者血糖水平,减少心肌纤维化和心肌重构,使心脏获益。展开更多
The Global Position System(GPS)is a reliable method for positioning in most scenarios,but it falls short in harsh environments like urban vehicular scenarios,where numerous trees or flyovers obstruct the signals.This ...The Global Position System(GPS)is a reliable method for positioning in most scenarios,but it falls short in harsh environments like urban vehicular scenarios,where numerous trees or flyovers obstruct the signals.This presents an unprecedented challenge for autonomous vehicles or applications requiring high accuracy.Fortunately,vehicular ad-hoc networks(VANET)offer an effective solution,where vehicle-to-vehicle(V2V)and vehicle-to-infrastructure(V2I)communications are used to enhance location awareness.In V2I communications,the roadside units(RSU)transmit beacon packets,and the vehicle receives numerous packets from different RSUs to establish communication.To further improve localization accuracy,a cross-covariance matrices-alternating least square(CCM-ALS)algorithm is proposed.The algorithm relies on ALS of the CCM for obtaining the position of vehicles in V2I communications.The algorithm is highly precise compared to traditional angle of arrival(AOA)positioning and not inferior to direct position determination(DPD)approaches while being low in complexity,which is crucial for moving vehicles.The numerical results verify the superiority of the proposed method.展开更多
The evolution of severe acute respiratory syndrome coronavirus 2(SARS-CoV-2)has resulted in mutations not only in the spike protein,aiding immune evasion,but also in the NSP3/4/6 proteins,crucial for regulating double...The evolution of severe acute respiratory syndrome coronavirus 2(SARS-CoV-2)has resulted in mutations not only in the spike protein,aiding immune evasion,but also in the NSP3/4/6 proteins,crucial for regulating double-membrane vesicle(DMV)formation.However,the functional consequences of these NSP3/4/6 mutations remain poorly understood.In this study,a systematic analysis was conducted to investigate the evolutionary patterns of NSP3/4/6 mutations and their impact on DMV formation.The findings revealed that the NSP4 T492I mutation,a prevalent mutation found in all Delta and Omicron sub-lineages,notably enhances DMV formation.Mechanistically,the NSP4 T492I mutation enhances its homodimerization,leading to an increase in the size of puncta induced by NSP3/4,and also augments endoplasmic reticulum(ER)membrane curvature,resulting in a higher DMV density per fluorescent puncta.This study underscores the significance of the NSP4 T492I mutation in modulating DMV formation,with potential implications for the transmission dynamics of SARS-CoV-2.It contributes valuable insights into how these mutations impact viral replication and pathogenesis.展开更多
车联网对于超高可靠与低时延通信(Ultra-Reliable and Low Latency Communications,URLLC)具有严格的要求,特别对于车到基础设施(Vehicle to Infrastructure,V2I)场景,URLLC对传输管理交通状况至关重要.3GPP Cellular-V2X(C-V2X)作为现...车联网对于超高可靠与低时延通信(Ultra-Reliable and Low Latency Communications,URLLC)具有严格的要求,特别对于车到基础设施(Vehicle to Infrastructure,V2I)场景,URLLC对传输管理交通状况至关重要.3GPP Cellular-V2X(C-V2X)作为现在支撑车联网URLLC主流的无线技术,仍存在技术挑战.为进一步提升通信性能,本文在V2I场景下,基于车载终端、路侧单元(Road Side Unit,RSU)与边缘计算车联网服务器(Internet of Vehicles Server,IoV Server)的交互,设计了一种基于C-V2I规范的智能信道估计框架.在IoV Server中,本文提出了一种基于深度学习的信道估计算法,该算法利用一维卷积神经网络(One Dimensional Convolution Neural Network,1D CNN)完成频域插值和条件循环单元(Conditional Recurrent Unit,CRU)进行时域状态预测,通过引入额外的速度编码矢量和多径编码矢量跟踪环境的变化,对不同移动环境下的信道数据进行精确训练.最后通过系统仿真与分析表明,所提算法能够通过信道参数编码追踪不同高速移动环境下的信道变化,实现对信道数据的精确训练.与车联网代表性信道估计算法相比,所提算法提升了信道估计精度,降低了误码率和增强了鲁棒性.展开更多
文摘无线信道建模对于理解、设计和优化无线通信系统具有重要意义,是无线通信领域中不可或缺的一部分。为了满足车联网(vehicle to everything,V2X)环境中的通信需求,研究空间中障碍物的分布对信道衰落特性的影响,本文提出了一种新的随机散射簇生成算法,即通过把Matérn硬核点过程和泊松簇过程相结合来模拟真实V2X信道中的障碍物。在算法中,依据真实环境障碍物的方位设置散射簇的坐标位置,根据周围障碍物密度合理设置簇内散射点数量。利用传播图论进行仿真,考虑直射路径和单跳散射路径,基于信道冲激响应(channel impulse response,CIR)分别研究了功率延迟分布(power delay profile,PDP)和多普勒功率谱密度(Doppler power spectrum density,DPSD),并分析了不同移动轨迹下的均方根(root mean square,RMS)时延扩展的累计分布函数(cumulative distribution function,CDF),以及莱斯K因子的分布特性和角度功率谱(power angular spectrum,PAS)的分布。本文研究验证得到,所提出的模型有助于分析车辆-基础设施(vehicle to infrastructure,V2I)通信场景下的时域非平稳特性,为V2X通信系统的设计和优化提供了重要参考。
文摘目的:观察高选择性钠-葡萄糖协同转运蛋白2抑制剂(SGLT2i)对2型糖尿病(T2DM)伴射血分数降低心衰(HFrEF)患者的治疗效果。方法:选取某院2023年1月—2024年1月收治的T2DM伴HFrEF患者86例为研究对象,采用随机数字表法分为观察组和对照组,各43例。对照组常规降糖和抗心衰治疗,观察组在对照组基础上联合SGLT2i治疗。比较2组血糖指标[空腹血糖(FPG)、餐后2 h血糖(2 h PBG)、糖化血红蛋白(HbA1c)]、血清心功能指标[N末端B型钠尿肽前体(NT-proBNP)、可溶性生长刺激表达基因2蛋白(sST2)]、左心功能指标[左心室射血分数(LVEF)、左心室舒张末期内径(LVEDD)、左心室收缩末期内径(LVESD)]及不良反应发生率。结果:治疗3个月后,观察组FPG[(6.91±1.45)mmol/L]、HbA1c[(6.72±1.40)%]水平低于对照组[(7.50±1.17)mmol/L、(7.25±1.17)%](P<0.05),2组2h PBG水平比较差异无统计学意义(P>0.05);观察组NT-proBNP[(1551.04±567.79)pg/mL]、sST2[(22.15±4.38)ng/mL]水平低于对照组[(1845.75±482.22)pg/mL、(25.79±6.34)ng/mL](P<0.05);观察组LVESD[(46.19±5.18)mm]、LVEDD[(52.02±5.12)mm]低于对照组[(48.58±5.29)mm、(54.89±5.98)mm],LVEF[(36.36±1.76)%]高于对照组[(35.49±2.15)%],差异均有统计学意义(P<0.05)。2组不良反应发生率比较差异无统计学意义(P>0.05)。结论:SGLT2i对T2DM伴HFrEF治疗效果良好,可有效降低患者血糖水平,减少心肌纤维化和心肌重构,使心脏获益。
基金supported by the National Natural Science Foundation of China(62371225).
文摘The Global Position System(GPS)is a reliable method for positioning in most scenarios,but it falls short in harsh environments like urban vehicular scenarios,where numerous trees or flyovers obstruct the signals.This presents an unprecedented challenge for autonomous vehicles or applications requiring high accuracy.Fortunately,vehicular ad-hoc networks(VANET)offer an effective solution,where vehicle-to-vehicle(V2V)and vehicle-to-infrastructure(V2I)communications are used to enhance location awareness.In V2I communications,the roadside units(RSU)transmit beacon packets,and the vehicle receives numerous packets from different RSUs to establish communication.To further improve localization accuracy,a cross-covariance matrices-alternating least square(CCM-ALS)algorithm is proposed.The algorithm relies on ALS of the CCM for obtaining the position of vehicles in V2I communications.The algorithm is highly precise compared to traditional angle of arrival(AOA)positioning and not inferior to direct position determination(DPD)approaches while being low in complexity,which is crucial for moving vehicles.The numerical results verify the superiority of the proposed method.
基金supported by the National Natural Science Foundation of China(92469107 to Z.Li)the R&D Program of Guangzhou National Laboratory(ZL-SRPG2200205 to Z.Li)the Guangdong Province High-level Talent Youth Project(2021QN02Y939 to Z.Li).
文摘The evolution of severe acute respiratory syndrome coronavirus 2(SARS-CoV-2)has resulted in mutations not only in the spike protein,aiding immune evasion,but also in the NSP3/4/6 proteins,crucial for regulating double-membrane vesicle(DMV)formation.However,the functional consequences of these NSP3/4/6 mutations remain poorly understood.In this study,a systematic analysis was conducted to investigate the evolutionary patterns of NSP3/4/6 mutations and their impact on DMV formation.The findings revealed that the NSP4 T492I mutation,a prevalent mutation found in all Delta and Omicron sub-lineages,notably enhances DMV formation.Mechanistically,the NSP4 T492I mutation enhances its homodimerization,leading to an increase in the size of puncta induced by NSP3/4,and also augments endoplasmic reticulum(ER)membrane curvature,resulting in a higher DMV density per fluorescent puncta.This study underscores the significance of the NSP4 T492I mutation in modulating DMV formation,with potential implications for the transmission dynamics of SARS-CoV-2.It contributes valuable insights into how these mutations impact viral replication and pathogenesis.
