Sustainability science: an ecohealth perspective

Sustainability science is emerging as a transdisciplinary effort to come to grips with the much-needed symbiosis between human activity and the environment. While there is recognition that conventional economic growth must yield to policies that foster sustainable development, this has not yet occurred on any broad scale. Rather, there is clear evidence that the Earth’s ecosystems and landscapes continue to degrade as a consequence of the cumulative impact of human activities. Taking an ecohealth approach to sustainability science provides a unique perspective on both the goals and the means to achieve sustainability. The goals should be the restoration of full functionality to the Earth’s ecosystems and landscapes, as measured by the key indicators of health: resilience, organization, vitality (productivity), and the absence of ecosystem distress syndrome. The means should be the coordinated (spatially and temporally) efforts to modify human behaviors to reduce cumulative stress impacts. Achieving ecosystem health should become the cornerstone of sustainability policy—for healthy ecosystems are the essential precondition for achieving sustainable livelihoods, human health, and many other societal objectives, as reflected in the Millennium Development Goals.     

医用防护口罩测试装置的对比研究

结合医用防护口罩实际使用工况,设计了两种针对环境气溶胶过滤性能的测试方法与装置.采集部分常用的防护口罩,分别采用TSI CERTITEST Models 8130型自动过滤测试仪及本文研发的测试装置DHU-Ⅰ平板型口罩性能测试台和DHU-Ⅱ实况型口罩性能测试台进行测试.对结果进行对比分析发现,DHU-Ⅰ平板型口罩性能测试台和8130型自动过滤测试仪测定结果比较接近,能够反映出防护口罩在环境大气中使用的情况;而DHU-Ⅱ实况型口罩性能测试台相对前两者而言,在吸气阻力基本不变的情况下,测得过滤效率降低近40%,结果更接近实际工况.     

Screening for trisomy 21 in twin pregnancies in the first trimester: does chorionicity impact on maternal serum free β-hCG or PAPP-A levels?

In a study of 180 twin pregnancies I have examined the distribution of maternal serum free β-human chorionic gonadotrophin (β-hCG) and pregnancy-associated plasma protein-A (PAPP-A), in addition to fetal nuchal translucency thickness (NT), in twins classified as monochorionic or dichorionic, based on ultrasound appearance at 10–14 weeks of gestation. In 45 monochorionic and 135 dichorionic twin pregnancies the median MoM free β-hCG was not significantly different (1.00 vs 1.01), whilst that for PAPP-A was lower (0.89 vs 1.01) but again with no statistical significance. Previous reports of an increased fetal NT in monochorionic twins pregnancies could not be confirmed (1.03 vs 1.00). It is concluded that the existing pseudo risk twin correction algorithm is appropriate for both monochorionic and dichorionic twins in providing accurate first trimester risks for trisomy 21. Copyright © 2001 John Wiley & Sons, Ltd.     

Mesomelic campomelia,polydactyly and Dandy–Walker cyst in siblings

The present report describes two fetuses, one female and one male, with thus far undescribed skeletal malformations. The mother was a gravida 2, para 0. Both pregnancies were terminated in the second trimester because of multiple congenital anomalies diagnosed ultrasonographically resembling a short rib-polydactyly syndrome. Both fetuses were found to have postaxial hexadactyly of the hands and feet, marked bilateral campomelia of the forearm and shank bones, and a Dandy–Walker cyst. In addition, the fourth ventricle was dilated in the first sibling and the second sibling had an inverse intestinal malrotation. A literature search failed to reveal similar observations. Copyright © 2001 John Wiley & Sons, Ltd.     

Maternal serum levels of total activin-A in first-trimester trisomy 21 pregnancies

Maternal serum total activin-A concentration was measured in 45 pregnancies affected by trisomy 21 and 493 control unaffected pregnancies at 10–14 weeks of gestation. In the trisomy 21 pregnancies total activin-A concentration was significantly higher (1.36 MoM of the unaffected pregnancies) and in 16% of cases the level was above the 95th centile of normal. The log₁₀ SD for the control group and the trisomy 21 group were 0.17 and 0.22, respectively. The median pregnancy associated plasma protein-A (PAPP-A) in this trisomy 21 series was 0.49 and for free β-hCG was 2.05. In the trisomy group there were significant positive associations between total activin-A and PAPP-A (0.6071) and free β-hCG (0.4255). The low median difference and the high overlap in values between trisomic and unaffected pregnancies make total activin-A of little practical use in first-trimester screening for trisomy 21. Copyright © 2001 John Wiley & Sons, Ltd.