巨灾风险的评估与政策

2006年3月．在美国内华达州大学召开了巨大自然灾害风险减轻政策管理顾问论坛会议．会议主题涉及美国巨灾发生发展的趋势、巨灾风险的识别分析评估及其管理政策等。本文主要介绍地震巨灾的风险研究评估和提出的管理政策方案。     

构建和谐社会做好服务与保障

沿海城市厦门市政府坚持“以人为本”的理念,切实把防震减灾工作纳入经济建设和社会发展的总体规划,努力营造全社会关心支持防震减灾工作的良好氛围,全面提高防震减灾能力,为构建和谐社会提供了有力的服务与保障。     

如何做好城市防震避险工作

对于生活在城市的居民来说,当遇到有感地震和破坏性地震时该如何识别、避险和逃生尤为重要。深入宣传教育,做好防震减灾准备工作心理承受能力与准备的程度成正比。地震知识掌握越多,防震物资准备越充分,思想准备越到位,震时就能够坦然面对,地震发生时就越能做到遇震不慌。反之,对地震常识一无所知,缺乏必要的思想与物资准备,     

水土气污染与人类自身生产

我国现实之患是旱涝沙,潜在之忧是水土气污染。这里水是指江河湖海和地下水,土是土壤,气为大气。水土气是养育人类的基本环境要素。即使是人类需要的生存环境,也得不到应有的珍惜和保护,这是人类的最大悲哀。960万平方公里陆地和300多万平方公里海洋足以让我国人民活得潇洒自在,健康快     

Prenatal diagnosis of congenital head,face, and neck malformations—Is complementary fetal MRI of value?

Objectives

The aim of this study was to evaluate the role of fetal magnetic resonance imaging (MRI) as a complement to ultrasound (US) in the prenatal diagnosis of craniofacial anomalies.

Methods

A historical cohort study including all pregnant women who were referred for fetal MRI because of antenatal diagnosis of craniofacial anomalies on screening US. Prenatal diagnostic US, MRI, and postnatal diagnosis were compared for consistencies and discrepancies.

Results

Forty-five pregnant women with 73 suspected fetal craniofacial anomalies diagnosed by US underwent MRI. In 40 out of 73 anomalies (54.8%), US and MRI findings were in complete agreement with postnatal diagnoses. MRI correctly ruled out the diagnosis of 24 anomalies suspected on US and diagnosed four additional pathologies that were not demonstrated by US. Out of the 85 anomalies (suspected by imaging or confirmed postnatally), confident diagnosis could be made by MRI in 68 anomalies (80%), not diagnosed in 10 (11.8%), and over-diagnosed in seven (8.2%). By US, confident diagnosis could be made in 44 anomalies (51.8%), not diagnosed in 11 (12.9%), and over-diagnosed in 30 (35.3%).

Conclusion

MRI is valuable in the antenatal evaluation of fetal craniofacial anomalies and may be useful as an adjunct to US in the prenatal work-up of craniofacial anomalies.     

The fragmentation patterns of maternal plasma cell-free DNA and its applications in non-invasive prenatal testing

The discovery of cell-free DNA (cfDNA) in maternal plasma has opened up new promises for the development of non-invasive prenatal testing (NIPT). Application of cfDNA in NIPT of fetus diseases and abnormalities is restricted by the low amount of fetal DNA molecules in maternal plasma. Fetus-derived cfDNA in maternal plasma are shorter than maternal DNA, thus leveraging the maternal and fetus-derived cfDNA molecules size difference has become a novel and more accurate method for NIPT. However, multiple biological properties such as size distribution of plasma DNA, proportion of fetal-derived DNA and methylation levels in maternal plasma across different gestational ages still remain largely unknown. Further insights into the size distribution and fragmentation pattern of circulating plasma cfDNA will shed light on the origin and fragmentation mechanisms of cfDNA during physiological and pathological processes in prenatal diseases and enhance our ability to take the advantage of plasma cfDNA as a molecular diagnostic tool. In the review, we start by summarizing the research techniques for the determination of the fragmentation profiles of cfDNA in maternal plasma. We then summarize the main progress and findings in size profiles of maternal plasma cfDNA and cffDNA. Finally, we discuss the potential diagnostic applications of plasma cfDNA size profiling.     

In situ electron-induced reduction of NOx via CNTs activated by DBD at low temperature

• An in situ electron-induced deNO_x process with CNT activated by DBD was achieved. • Carbon atoms on CNT surface were verified to be excited by plasma in DBD-CNT system. • Reactions between NO_x and excited C result in synergistic effect of DBD-CNT system. In this study, a new in situ electron-induced process is presented with carbon nanotubes (CNTs) as a reduction agent activated by dielectric barrier discharge (DBD) for nitrogen oxide (NO_x) abatement at low temperature (<407 K). Compared with a single DBD system and a DBD system with activated carbon (DBD-AC), a DBD system with carbon nanotubes (DBD-CNT) showed a significant promotion of NO_x removal efficiency and N₂ selectivity. Although the O₂ content was 10%, the NO_x conversion and N₂ selectivity in the DBD-CNT system still reached 64.9% and 81.9% at a specific input energy (SIE) of 1424 J/L, and these values decreased to 16.8%, 31.9% and 43.2%, 62.3% in the single DBD system and the DBD-AC system, respectively. X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM) were utilized to investigate surface changes in the CNTs after activation by DBD to explore the NO_x reduction abatement mechanism of this new process. Furthermore, the outlet gas components were also observed via Fourier transform infrared spectroscopy (FTIR) to help reveal the NO_x reduction mechanism. Experimental results verified that carbon atoms excited by DBD and the structure of CNTs contributed to the synergistic activity of the DBD-CNT system. The new deNO_x process was accomplished through in situ heterogenetic reduction reactions between the NO_x and carbon atoms activated by the plasma on the CNTs. In addition, further results indicated that the new deNO_x process exhibited acceptable SO₂ tolerance and water resistance.