Depression is a prevalent mental disorder in contemporary society. Symbolic phase transfer entropy can quantify the dynamic interaction and information flow between electroencephalogram (EEG) signals in depressed patients and healthy groups, which can help diagnose and treat depression. However, the traditional symbolization process of symbolic phase transfer entropy adopts the basic template method, which makes the symbolic phase transfer entropy unable to express the characteristics and changes of time series in different time periods in detail. Therefore, this paper proposes an improved symbolic phase transfer entropy algorithm, which adopts the adaptive template method in the symbolization process of the symbolic phase transfer entropy algorithm so that it can capture the dynamic changes of time series more finely. It was verified on the task EEG signals of 40 depressed patients and 40 healthy people. The experimental results show that the improved symbolic phase transfer entropy can more accurately distinguish depressed patients from healthy people in lead F4 and lead O1, which is helpful for the study of the EEG pathological characteristics of depression. The improved symbolic phase transfer entropy algorithm makes up for the shortcomings of the traditional symbolic phase transfer entropy in capturing the dynamic changes of time series and provides help for the study of dynamic changes in complex systems.
目的 通过三维有限元方法分析下颌骨囊性病变在咬合状态和外伤因素中颌骨骨折的致伤机制,为下颌骨骨折的预防和治疗提供参考.方法 选择1 名健康志愿者的颌骨CT图像资料,建立下颌骨囊性病变三维模型.分别模拟咬合与非咬合状态下,不同外力分别作用于下颌体左侧、正中处、右侧时下颌骨囊性病变的应力变化.结果 仅有外力作用下,当外力增大为1000N时,创伤位点位于下颌体右侧、正中处和左侧的应力值分别为85.81 MPa、73.47 MPa、80.32 MPa,囊性病变区域的应力逐渐增大.在咬合状态下,当外力为 200 N时,下颌体右侧、正中处和左侧的最大应力值分别达到了 84.50 MPa、85.52 MPa、80.6 MPa,应力主要集中于磨牙区和囊性病变区域.结论 无咬合状态时下颌体右侧受到外伤时易导致骨折,咬合状态下下颌骨受到外伤时骨折发生的风险较高,且下颌体右侧和正中处受到外伤时更易导致骨折.
1 故障现象 iCT 机器无钥匙框,拧开机钥匙无反应. 2 故障分析及维修 iCT 在开机时机架上电无钥匙框,初步判断是机器通信自检没通过.iCT 采用的是CAN 通信实时控制的串行通信网络,其不同节点可同时接收到相同的数据,保证了实时数据通信.iCT 通信由机架、扫描床、束光器、探测器和旋转部分5 个模块组成,任一模块有故障就会导致机架开机后无钥匙框.
目的 评估B型主动脉夹层在不同撕裂口条件下真、假腔的腔间压力功能参数变化,量化撕裂口对主动脉夹层血流动力学的影响.方法 基于1 例B型主动脉夹层患者的CTA数据进行三维血管重建,利用3D打印技术构建6 种不同撕裂口大小、位置、数量的主动脉夹层血管模型.借助体外仿生循环系统和多通道同步压力监测装置,完成对血管真假腔间压力的同步采集,分析不同撕裂口工况下的血管内压力并计算真假腔间压力差.结果 对比 4mm的小撕裂口、大撕裂口(10 mm)模型的真假腔间压力差减小,最大变化幅度为1.5 mmHg;撕裂口位置改变导致真腔与假腔内压力相对大小发生反转(-1.7 mmHg vs 1.6 mmHg;-1.1 mmHg vs 2.3 mmHg);相对于单个撕裂口,两个撕裂口使真假腔压力趋于平衡,压力差维持在0 mmHg附近.结论 B型主动脉夹层中撕裂口的大小、位置和数量对真假腔间压力差均有显著影响,临床中需根据不同撕裂口形态及风险水平确定最佳的手术干预决策.
1 故障现象 西门子Avanto 型核磁扫描仪扫描停止,重启设备后又可继续扫描,严重时需要多次重启. 2 故障分析及维修 首先更换梯度接口转换板,此时梯度小信号系统所有电源电压上调+4％,测试射频控制接口正常.
