In order to measure the location of medical micro-devices in the gastrointestinal tract, electro-magnetic methods were developed considering the magnetic permeability of human bodies. Two varieties of electromagnetic ...In order to measure the location of medical micro-devices in the gastrointestinal tract, electro-magnetic methods were developed considering the magnetic permeability of human bodies. Two varieties of electromagnetic localization methods have been implemented: one uses direct current(DC) to generate the elec-tromagnetic field, and the other uses alternating current (AC). The two varieties of the localization principle were analyzed and relevant experiments were made. The experiments show that the alternating electromagnetic method acquires higher accuracy, higher stability and wider measurement range.展开更多
基金Project Vivafunded by the U.S. Environmental Protection Agency(RD83479801)the National Institutes of Health(K24 HD069408,R37 HD 034568, P01 ES009825)
文摘[背景]对成人的研究已表明,空气污染暴露与血压升高有关。[目的]研究产前暴露于空气污染物与新生儿收缩压(SBP)之间的关联。[方法]研究马萨诸塞州波士顿市地区出生前队列中的1 131对母婴,计算各妊娠期以及产前2~90 d在固定监测点测量的时间分辨的细颗粒物(≤2.5μm;PM2.5)、炭黑(BC)、一氧化氮(氮氧化合物)、二氧化氮(NO2)、臭氧(O3)和一氧化碳(CO)的平均暴露水平,并估计居住点水平上时空分辨的PM2.5和BC暴露。用自动仪器测量平均年龄为(30±18)h新生儿的收缩压,并使用混合效应模型检验空气污染物暴露与SBP之间的关联,分析中考虑了测量环境、孩子的出生体重、母亲的年龄、种族/族裔、社会经济地位、妊娠后期BP以及时间趋势。估计值表示为每一种污染物每增加一个四分位数间距(IQR)所致的SBP差异。[结果]在妊娠后期,较高的平均PM2.5和BC暴露与较高的SBP有关联[例如,居住地90 d BC平均值增加0.32μg/m3与SBP升高1.0(95%CI:0.1~1.8)mm Hg有关联]。相比之下,O3与SBP呈负相关[例如,产前90 d O3升高13.5×10-9与SBP降低2.3(95%CI:-4.4^-0.2)mm Hg有关联]。[结论]妊娠后期暴露于PM2.5和BC与新生儿SBP呈正相关,而O3与SBP呈负相关。纵向随访能够评估这些研究结果对这些新生儿随之的童年期和成年期的健康影响。
基金the Specialized Research Fundfor the Doctoral Program of Higher Education(No. 20040248033)the National High Technology Research and Development Program (863) of China(No. 2006AA04Z368)
文摘In order to measure the location of medical micro-devices in the gastrointestinal tract, electro-magnetic methods were developed considering the magnetic permeability of human bodies. Two varieties of electromagnetic localization methods have been implemented: one uses direct current(DC) to generate the elec-tromagnetic field, and the other uses alternating current (AC). The two varieties of the localization principle were analyzed and relevant experiments were made. The experiments show that the alternating electromagnetic method acquires higher accuracy, higher stability and wider measurement range.
