本文研究并比较了基于MMAe赋权的模型平均下,Wald置信区间,MATA置信区间,及Bootstrap置信区间的覆盖率、区间长度、左右错误率等各方面的表现性能。不同信噪比水平下的模拟显示,Wald置信区间在低信噪比时有更好的覆盖率,高信噪比下,三...本文研究并比较了基于MMAe赋权的模型平均下,Wald置信区间,MATA置信区间,及Bootstrap置信区间的覆盖率、区间长度、左右错误率等各方面的表现性能。不同信噪比水平下的模拟显示,Wald置信区间在低信噪比时有更好的覆盖率,高信噪比下,三者覆盖率相近,MATA置信区间相对长度更短。在与MMA等其他模型平均方法的横向比较中,MMAe的赋权在Wald、MATA及Bootstrap三种置信区间的构建下,均比其他赋权方式在更低的样本量下更早达到名义覆盖率。最后在实例中考察MMAe在不同置信区间下的表现,与模拟表现一致。This article studies and compares the performance of models based on MMAe weighting in terms of coverage, interval length, left and right error rates under average, Wald confidence interval, MATA confidence interval, and Bootstrap confidence interval. Simulations at different levels of signal show that the Wald confidence interval has better coverage at low signal, while at high signal, the three’s confidence interval has similar coverage, and the MATA confidence interval is relatively shorter in length. In the horizontal comparison with other model averaging methods such as MMA, the weighting of MMAe reached nominal coverage earlier than other weighting methods at lower sample sizes under the construction of Wald, MATA, and Bootstrap confidence intervals. Finally, the performance of MMAe at different confidence intervals was examined in the example, which was consistent with the simulation results.展开更多
目的探讨单核细胞单层实验(monocyte monolayer assay,MMA)是否能够用于IgG抗-M相关胎儿新生儿溶血病(hemolytic disease of fetus and newborn,HDFN)的预测。方法选取8例含有IgG抗-M的孕妇并采集血浆标本,其中有胎儿水肿等严重临床症...目的探讨单核细胞单层实验(monocyte monolayer assay,MMA)是否能够用于IgG抗-M相关胎儿新生儿溶血病(hemolytic disease of fetus and newborn,HDFN)的预测。方法选取8例含有IgG抗-M的孕妇并采集血浆标本,其中有胎儿水肿等严重临床症状及无明显临床症状的各4例;8份血浆用二硫苏糖醇(dithiothreitol,DTT)灭活,与M抗原阳性红细胞孵育致敏后,将致敏红细胞与单核细胞混合进行吞噬试验,同时设立阳性及阴性对照,并计算吞噬率;采用t检验对2组吞噬率进行比较。结果4例发生严重抗-M相关HDFN的孕妇的MMA吞噬率分别为15.37%、13.05%、9.17%和24.50%,均值为15.52%;检出IgG抗-M但未发生HDFN的孕妇,其MMA吞噬率分别为8.74%、11.07%、5.12%和6.23%,均值为7.79%,2组吞噬率无差异(P>0.05)。2组吞噬率分别与阴性对照比较均无差异(P>0.05),但均明显低于阳性对照(P<0.05)。结论IgG抗-M介导单核细胞吞噬的能力较低,提示抗-M导致胎儿水肿的机制可能并非红细胞被吞噬破坏而发生的溶血,因此体外单核细胞单层实验可能不适用于IgG抗-M相关HDFN的预测。对于检出IgG抗-M的孕妇,现仍需通过定期监测胎儿大脑中动脉血流,来判断胎儿宫内贫血情况。展开更多
The waterborne polyurethane-acrylate hybrid emulsions modified by methyl methacrylate(MMA)and butyl acrylate(BA)copolymer were synthesized by using 1,4-butanediol(BDO),dimethylopropionic(DMPA)and adipic dihyrazide(ADH...The waterborne polyurethane-acrylate hybrid emulsions modified by methyl methacrylate(MMA)and butyl acrylate(BA)copolymer were synthesized by using 1,4-butanediol(BDO),dimethylopropionic(DMPA)and adipic dihyrazide(ADH)as chain extenders.The effects of the amounts of BA and diacetone acrylamide(DAAM)on the properties of hybrid emulsions,films and adhesive were studied.The structure of the hybrid emulsions was characterized with Fourier transform infrared(FTIR).The experiment results showed that when the amount of BA was 4.0%—6.0%,that of DAAM was 2.0%—3.0%,the properties of the hybrid emulsion,films and adhesive were satisfactory.The adhesive which was made by polyurethane-acrylate hybrid emulsion with a better adhesive for wood.展开更多
文摘本文研究并比较了基于MMAe赋权的模型平均下,Wald置信区间,MATA置信区间,及Bootstrap置信区间的覆盖率、区间长度、左右错误率等各方面的表现性能。不同信噪比水平下的模拟显示,Wald置信区间在低信噪比时有更好的覆盖率,高信噪比下,三者覆盖率相近,MATA置信区间相对长度更短。在与MMA等其他模型平均方法的横向比较中,MMAe的赋权在Wald、MATA及Bootstrap三种置信区间的构建下,均比其他赋权方式在更低的样本量下更早达到名义覆盖率。最后在实例中考察MMAe在不同置信区间下的表现,与模拟表现一致。This article studies and compares the performance of models based on MMAe weighting in terms of coverage, interval length, left and right error rates under average, Wald confidence interval, MATA confidence interval, and Bootstrap confidence interval. Simulations at different levels of signal show that the Wald confidence interval has better coverage at low signal, while at high signal, the three’s confidence interval has similar coverage, and the MATA confidence interval is relatively shorter in length. In the horizontal comparison with other model averaging methods such as MMA, the weighting of MMAe reached nominal coverage earlier than other weighting methods at lower sample sizes under the construction of Wald, MATA, and Bootstrap confidence intervals. Finally, the performance of MMAe at different confidence intervals was examined in the example, which was consistent with the simulation results.
文摘目的探讨单核细胞单层实验(monocyte monolayer assay,MMA)是否能够用于IgG抗-M相关胎儿新生儿溶血病(hemolytic disease of fetus and newborn,HDFN)的预测。方法选取8例含有IgG抗-M的孕妇并采集血浆标本,其中有胎儿水肿等严重临床症状及无明显临床症状的各4例;8份血浆用二硫苏糖醇(dithiothreitol,DTT)灭活,与M抗原阳性红细胞孵育致敏后,将致敏红细胞与单核细胞混合进行吞噬试验,同时设立阳性及阴性对照,并计算吞噬率;采用t检验对2组吞噬率进行比较。结果4例发生严重抗-M相关HDFN的孕妇的MMA吞噬率分别为15.37%、13.05%、9.17%和24.50%,均值为15.52%;检出IgG抗-M但未发生HDFN的孕妇,其MMA吞噬率分别为8.74%、11.07%、5.12%和6.23%,均值为7.79%,2组吞噬率无差异(P>0.05)。2组吞噬率分别与阴性对照比较均无差异(P>0.05),但均明显低于阳性对照(P<0.05)。结论IgG抗-M介导单核细胞吞噬的能力较低,提示抗-M导致胎儿水肿的机制可能并非红细胞被吞噬破坏而发生的溶血,因此体外单核细胞单层实验可能不适用于IgG抗-M相关HDFN的预测。对于检出IgG抗-M的孕妇,现仍需通过定期监测胎儿大脑中动脉血流,来判断胎儿宫内贫血情况。
文摘The waterborne polyurethane-acrylate hybrid emulsions modified by methyl methacrylate(MMA)and butyl acrylate(BA)copolymer were synthesized by using 1,4-butanediol(BDO),dimethylopropionic(DMPA)and adipic dihyrazide(ADH)as chain extenders.The effects of the amounts of BA and diacetone acrylamide(DAAM)on the properties of hybrid emulsions,films and adhesive were studied.The structure of the hybrid emulsions was characterized with Fourier transform infrared(FTIR).The experiment results showed that when the amount of BA was 4.0%—6.0%,that of DAAM was 2.0%—3.0%,the properties of the hybrid emulsion,films and adhesive were satisfactory.The adhesive which was made by polyurethane-acrylate hybrid emulsion with a better adhesive for wood.
