目的评估高分辨率CT(HRCT)检查在耳硬化症诊断中的价值。方法回顾性分析经手术确诊且资料完整的21例(31耳)耳硬化症患者的临床资料,年龄21~62岁,平均38.2±11.4岁。所有患者术前接受0.625 mm薄层HRCT检查,依据HRCT检查结果分为三组...目的评估高分辨率CT(HRCT)检查在耳硬化症诊断中的价值。方法回顾性分析经手术确诊且资料完整的21例(31耳)耳硬化症患者的临床资料,年龄21~62岁,平均38.2±11.4岁。所有患者术前接受0.625 mm薄层HRCT检查,依据HRCT检查结果分为三组(因拟单侧手术,故以单侧21耳分组):HRCT阴性组(4耳)、窗前型组(11耳)和混合型组(6耳),与术中确诊比较HRCT诊断耳硬化症的检出率,比较各组术前和术后3个月的纯音气导(air conduction,AC)、骨导(bone conduction,BC)阈值和气骨导差(air bone gap,ABG)值。结果手术确诊为耳硬化症的21例患者中有17例患者术前HRCT检查发现耳硬化病变,检出率80.95%(17/21),其中10例(10/17,58.82%)为双侧耳硬化症。CT阴性组、窗前型组和混合型组术前平均AC阈值分别为52.8±13.9、57.7±10.0和62.7±16.7 dB HL,差异无统计学意义(P>0.05);三组术后3个月平均AC阈值分别为26.6±11.6、40.3±27.0和58.8±8.8 dB HL,差异有统计学意义(P<0.05);三组术前平均BC阈值分别为25.6±10.1、30.5±6.5和37.1±14.4 dB HL,术后分别为25.3±10.7、29.9±17.6和45.0±13.0 dB HL,均无统计学差异(P>0.05)。术前三组间ABG差异无统计学意义(P>0.05),术后HRCT阴性组ABG明显小于混合型组(P<0.05),与CT阴性组和窗前型组相比,混合型组患者术前和术后气、骨导阈值均较高;CT阴性组(P=0.014)和窗前型组(P=0.044)术后的AC听力较混合型组明显提高。术后混合型组和窗前型组中各有1耳发生感音神经性听力损失。结论 HRCT对于耳硬化症的诊断有较高的阳性率,尤其是窗前型;HCRT诊断为混合型耳硬化症者听力下降严重,术后听力改善不如CT阴性及窗前型者。展开更多
Using a combination of analytical and numerical methods, the paper studies bifurcations and chaotic motions of a two-dimensional airfoil with cubic nonlinearity in incompressible flow. One type of critical points (cha...Using a combination of analytical and numerical methods, the paper studies bifurcations and chaotic motions of a two-dimensional airfoil with cubic nonlinearity in incompressible flow. One type of critical points (characterized by a negative eigenvalue, a simple zero eigenvalue and a pair of purely imaginary eigenvalues) for the bifurcation response equations is considered. With the aid of the normal form theory, the explicit expressions of the critical bifurcation lines leading to incipient and secondary bifurcations are obtained. The stability of the bifurcation solutions is also investigated. By using the undetermined coefficient method, the homoclinic orbit is found, and the uniform convergence of the homoclinic orbit series expansion is proved. It analytically demonstrates that there exists a homoclinic orbit joining the initial equilibrium point to itself, therefore Smale horseshoe chaos occurs for this system via Si'lnikov criterion. The system evolves into chaotic motion through period-doubling bifurcation, and is periodic again as the dimensionless airflow speed increases. Numerical simulations are also given, which confirm the analytical results.展开更多
文摘目的评估高分辨率CT(HRCT)检查在耳硬化症诊断中的价值。方法回顾性分析经手术确诊且资料完整的21例(31耳)耳硬化症患者的临床资料,年龄21~62岁,平均38.2±11.4岁。所有患者术前接受0.625 mm薄层HRCT检查,依据HRCT检查结果分为三组(因拟单侧手术,故以单侧21耳分组):HRCT阴性组(4耳)、窗前型组(11耳)和混合型组(6耳),与术中确诊比较HRCT诊断耳硬化症的检出率,比较各组术前和术后3个月的纯音气导(air conduction,AC)、骨导(bone conduction,BC)阈值和气骨导差(air bone gap,ABG)值。结果手术确诊为耳硬化症的21例患者中有17例患者术前HRCT检查发现耳硬化病变,检出率80.95%(17/21),其中10例(10/17,58.82%)为双侧耳硬化症。CT阴性组、窗前型组和混合型组术前平均AC阈值分别为52.8±13.9、57.7±10.0和62.7±16.7 dB HL,差异无统计学意义(P>0.05);三组术后3个月平均AC阈值分别为26.6±11.6、40.3±27.0和58.8±8.8 dB HL,差异有统计学意义(P<0.05);三组术前平均BC阈值分别为25.6±10.1、30.5±6.5和37.1±14.4 dB HL,术后分别为25.3±10.7、29.9±17.6和45.0±13.0 dB HL,均无统计学差异(P>0.05)。术前三组间ABG差异无统计学意义(P>0.05),术后HRCT阴性组ABG明显小于混合型组(P<0.05),与CT阴性组和窗前型组相比,混合型组患者术前和术后气、骨导阈值均较高;CT阴性组(P=0.014)和窗前型组(P=0.044)术后的AC听力较混合型组明显提高。术后混合型组和窗前型组中各有1耳发生感音神经性听力损失。结论 HRCT对于耳硬化症的诊断有较高的阳性率,尤其是窗前型;HCRT诊断为混合型耳硬化症者听力下降严重,术后听力改善不如CT阴性及窗前型者。
基金supported by the National Natural Science Foundation of China (Grant Nos. 10972099, 10632040)China Postdoctoral Science Foundation (Grant No. 20090450765)the Natural Science Foundation of Tianjin, China (Grant No. 09JCZDJC26800)
文摘Using a combination of analytical and numerical methods, the paper studies bifurcations and chaotic motions of a two-dimensional airfoil with cubic nonlinearity in incompressible flow. One type of critical points (characterized by a negative eigenvalue, a simple zero eigenvalue and a pair of purely imaginary eigenvalues) for the bifurcation response equations is considered. With the aid of the normal form theory, the explicit expressions of the critical bifurcation lines leading to incipient and secondary bifurcations are obtained. The stability of the bifurcation solutions is also investigated. By using the undetermined coefficient method, the homoclinic orbit is found, and the uniform convergence of the homoclinic orbit series expansion is proved. It analytically demonstrates that there exists a homoclinic orbit joining the initial equilibrium point to itself, therefore Smale horseshoe chaos occurs for this system via Si'lnikov criterion. The system evolves into chaotic motion through period-doubling bifurcation, and is periodic again as the dimensionless airflow speed increases. Numerical simulations are also given, which confirm the analytical results.
