The purpose of this study was to determine the effectiveness of a fetal anatomy survey in conjunction with first-trimester nuchal translucency (NT) screening ultrasound in an unselected pregnant population performed b...The purpose of this study was to determine the effectiveness of a fetal anatomy survey in conjunction with first-trimester nuchal translucency (NT) screening ultrasound in an unselected pregnant population performed by sonographers. Study design: This was a prospective observational study of women presenting for NT screening for chromosomal defects. An anatomic survey was performed after a standardized protocol with a maximum scan time of 30 minutes. Results: Three hundred twenty-five singleton fetuses (11+ 0 to 13+ 6 weeks)- were examined and pregnancy outcome was available for 300 (92.3% ) of cases. In 89 (24.6% ) cases, transvaginal ultrasound was performed. The following fetal structures were seen in 95% of cases: cranium and intracranial anatomy, face, cord insertion, stomach, and all 4 limbs. The bladder was visualized in 89.5% of cases, the cardiac 4 chamber view in 84% , and the spine in only 45% of cases. Complete anatomy was seen in 109 (33% ). Crown rump length greater than 55 mm and sonographer experience were important factors contributing to anatomic visibility. Of a total of 6 congenital defects in this cohort, 1 was detected in the first trimester (neural tube defect), 4 at the 18- to 20- week anatomic scan, and 1 postnatally. Conclusion: A complete anatomy survey was successful in 33% of first-trimester fetuses in a time-limited sonographer based screening program. Since some anomalies are not evident in the first trimester, the 18- to 20- week scan remains the gold standard.展开更多
目的探讨结核感染T细胞酶联免疫斑点试验(T cells spot test of tuberculosis infection,T-SPOT.TB)与结核蛋白芯片检测在结核性脑膜炎(tuberculous meningitis,TBM)中的辅助诊断价值。方法采集TBM患者血标本分别进行T-SPOT.TB与结核蛋...目的探讨结核感染T细胞酶联免疫斑点试验(T cells spot test of tuberculosis infection,T-SPOT.TB)与结核蛋白芯片检测在结核性脑膜炎(tuberculous meningitis,TBM)中的辅助诊断价值。方法采集TBM患者血标本分别进行T-SPOT.TB与结核蛋白芯片检测,并对2种方法进行评价分析。结果 T-SPOT.TB检测TBM的敏感度和准确度分别为71.88%、77.97%,高于结核蛋白芯片检测的48.78%、60.29%(P<0.05或<0.01),TSPOT.TB和结核蛋白芯片检测TBM的特异度差异无统计学意义(85.19%vs 77.78%,P>0.05)。结论在辅助诊断TBM方面T-SPOT.TB检测方法优于结核蛋白芯片检测。展开更多
Corner detection is a chief step in computer vision. A new corner detection algorithm in planar curves is proposed. Firstly, from the human perception, two key characteristics are given as an amendment of the traditio...Corner detection is a chief step in computer vision. A new corner detection algorithm in planar curves is proposed. Firstly, from the human perception, two key characteristics are given as an amendment of the traditional corner properties. Based on the two properties, the concept of the fuzzy set is introduced into a detection. Secondly, the extracted-formulae of three groups including the features of the corner subject degree are derived. Through synthesizing the features of three groups, the judgments of the corner detection, location, and optimization are obtained. Finally, by using the algorithm the detection results of several examples and feature curves for some interested parts, as well as the detection results for the test images history in references are given. Results show that the algorithm is easily realized after adopting the fuzzy set, and the detection effect is very ideal.展开更多
The evolution of stresses due to inhomogeneity in metal injection molding （MIM） parts during sintering was investigated. The sintering model of porous materials during densification process was developed based on th...The evolution of stresses due to inhomogeneity in metal injection molding （MIM） parts during sintering was investigated. The sintering model of porous materials during densification process was developed based on the continuum mechanics and thermal elasto-viseoplastic constitutive law. Model parameters were identified from the dilatometer sintering experiment. The real density distribution of green body was measured by X-ray computed tomography （CT）, which was regarded as the initial condition of sintering model. Numerical calculation of the above sintering model was carried out with the finite element soRware Abaqus, through the user-defined material mechanical behavior （UMAT）. The calculation results showed that shrinkages of low density regions were faster than those of high density regions during sintering, which led to internal stresses. Compressive stresses existed in high density regions and tensile stresses existed in low density regions. The densification of local regions depended on not only the initial density, but also the evolution of stresses during the sintering stage.展开更多
文摘The purpose of this study was to determine the effectiveness of a fetal anatomy survey in conjunction with first-trimester nuchal translucency (NT) screening ultrasound in an unselected pregnant population performed by sonographers. Study design: This was a prospective observational study of women presenting for NT screening for chromosomal defects. An anatomic survey was performed after a standardized protocol with a maximum scan time of 30 minutes. Results: Three hundred twenty-five singleton fetuses (11+ 0 to 13+ 6 weeks)- were examined and pregnancy outcome was available for 300 (92.3% ) of cases. In 89 (24.6% ) cases, transvaginal ultrasound was performed. The following fetal structures were seen in 95% of cases: cranium and intracranial anatomy, face, cord insertion, stomach, and all 4 limbs. The bladder was visualized in 89.5% of cases, the cardiac 4 chamber view in 84% , and the spine in only 45% of cases. Complete anatomy was seen in 109 (33% ). Crown rump length greater than 55 mm and sonographer experience were important factors contributing to anatomic visibility. Of a total of 6 congenital defects in this cohort, 1 was detected in the first trimester (neural tube defect), 4 at the 18- to 20- week anatomic scan, and 1 postnatally. Conclusion: A complete anatomy survey was successful in 33% of first-trimester fetuses in a time-limited sonographer based screening program. Since some anomalies are not evident in the first trimester, the 18- to 20- week scan remains the gold standard.
文摘目的探讨结核感染T细胞酶联免疫斑点试验(T cells spot test of tuberculosis infection,T-SPOT.TB)与结核蛋白芯片检测在结核性脑膜炎(tuberculous meningitis,TBM)中的辅助诊断价值。方法采集TBM患者血标本分别进行T-SPOT.TB与结核蛋白芯片检测,并对2种方法进行评价分析。结果 T-SPOT.TB检测TBM的敏感度和准确度分别为71.88%、77.97%,高于结核蛋白芯片检测的48.78%、60.29%(P<0.05或<0.01),TSPOT.TB和结核蛋白芯片检测TBM的特异度差异无统计学意义(85.19%vs 77.78%,P>0.05)。结论在辅助诊断TBM方面T-SPOT.TB检测方法优于结核蛋白芯片检测。
文摘Corner detection is a chief step in computer vision. A new corner detection algorithm in planar curves is proposed. Firstly, from the human perception, two key characteristics are given as an amendment of the traditional corner properties. Based on the two properties, the concept of the fuzzy set is introduced into a detection. Secondly, the extracted-formulae of three groups including the features of the corner subject degree are derived. Through synthesizing the features of three groups, the judgments of the corner detection, location, and optimization are obtained. Finally, by using the algorithm the detection results of several examples and feature curves for some interested parts, as well as the detection results for the test images history in references are given. Results show that the algorithm is easily realized after adopting the fuzzy set, and the detection effect is very ideal.
基金Project(2011CB606306)supported by the National Basic Research Program of ChinaProject(FRF-TP-10-003B)supported by the Fundamental Research Funds for the Central Universities,ChinaProject(51274040)supported by the National Natural Science Foundation of China
文摘The evolution of stresses due to inhomogeneity in metal injection molding （MIM） parts during sintering was investigated. The sintering model of porous materials during densification process was developed based on the continuum mechanics and thermal elasto-viseoplastic constitutive law. Model parameters were identified from the dilatometer sintering experiment. The real density distribution of green body was measured by X-ray computed tomography （CT）, which was regarded as the initial condition of sintering model. Numerical calculation of the above sintering model was carried out with the finite element soRware Abaqus, through the user-defined material mechanical behavior （UMAT）. The calculation results showed that shrinkages of low density regions were faster than those of high density regions during sintering, which led to internal stresses. Compressive stresses existed in high density regions and tensile stresses existed in low density regions. The densification of local regions depended on not only the initial density, but also the evolution of stresses during the sintering stage.
