Multicenter clinical experience with non-invasive cell-free DNA screening for monosomy X and related X-chromosome variants

Objective

We aimed to investigate how the presence of fetal anomalies and different X chromosome variants influences Cell-free DNA (cfDNA) screening results for monosomy X.

Methods

From a multicenter retrospective survey on 673 pregnancies with prenatally suspected or confirmed Turner syndrome, we analyzed the subgroup for which prenatal cfDNA screening and karyotype results were available. A cfDNA screening result was defined as true positive (TP) when confirmatory testing showed 45,X or an X-chromosome variant.

Results

We had cfDNA results, karyotype, and phenotype data for 55 pregnancies. cfDNA results were high risk for monosomy X in 48/55, of which 23 were TP and 25 were false positive (FP). 32/48 high-risk cfDNA cases did not show fetal anomalies. Of these, 7 were TP. All were X-chromosome variants. All 16 fetuses with high-risk cfDNA result and ultrasound anomalies were TP. Of fetuses with abnormalities, those with 45,X more often had fetal hydrops/cystic hygroma, whereas those with “variant” karyotypes had different anomalies.

Conclusion

Both, 45,X or X-chromosome variants can be detected after a high-risk cfDNA result for monosomy X. When there are fetal anomalies, the result is more likely a TP. In the absence of fetal anomalies, it is most often an FP or X-chromosome variant.     

The practice of valuing the environment in cost-benefit analyses in transport and spatial projects

Scientific debates on environmental impacts in cost-benefit analysis (CBA) focus on methodological questions. The literature, however, contains very little information on the influence of these debates on CBAs made in spatial planning practice. In this paper, this gap is filled by a qualitative analysis of 67 CBAs made in the Netherlands between 2000 and 2011. From the literature on environmental valuation, we derive criteria to evaluate the quality of CBA practice, such as completeness and the inclusion of uncertainties. The analysis shows that in many cases relevant environmental effects are omitted or not monetised. Moreover, non-monetised effects are often not included in CBA conclusions. If impacts are monetised, the methods used are frequently not very sophisticated. The consequences of assumptions are often not communicated, for example, where high discount rates make long-term effects seem unimportant. In this research we identify four main points for good practice.     

The missing pieces for better future predictions in subarctic ecosystems: A Torneträsk case study

Arctic and subarctic ecosystems are experiencing substantial changes in hydrology, vegetation, permafrost conditions, and carbon cycling, in response to climatic change and other anthropogenic drivers, and these changes are likely to continue over this century. The total magnitude of these changes results from multiple interactions among these drivers. Field measurements can address the overall responses to different changing drivers, but are less capable of quantifying the interactions among them. Currently, a comprehensive assessment of the drivers of ecosystem changes, and the magnitude of their direct and indirect impacts on subarctic ecosystems, is missing. The Torneträsk area, in the Swedish subarctic, has an unrivalled history of environmental observation over 100 years, and is one of the most studied sites in the Arctic. In this study, we summarize and rank the drivers of ecosystem change in the Torneträsk area, and propose research priorities identified, by expert assessment, to improve predictions of ecosystem changes. The research priorities identified include understanding impacts on ecosystems brought on by altered frequency and intensity of winter warming events, evapotranspiration rates, rainfall, duration of snow cover and lake-ice, changed soil moisture, and droughts. This case study can help us understand the ongoing ecosystem changes occurring in the Torneträsk area, and contribute to improve predictions of future ecosystem changes at a larger scale. This understanding will provide the basis for the future mitigation and adaptation plans needed in a changing climate.Electronic supplementary materialThe online version of this article (10.1007/s13280-020-01381-1) contains supplementary material, which is available to authorized users.     

Nitrated monoaromatic hydrocarbons (nitrophenols,nitrocatechols, nitrosalicylic acids) in ambient air: levels,mass size distributions and inhalation bioaccessibility

Environmental Science and Pollution Research - Nitrated monoaromatic hydrocarbons (NMAHs) are ubiquitous in the environment and an important part of atmospheric humic-like substances (HULIS) and...     

Plant growth regulators and EDTA improve phytoremediation potential and antioxidant response of Dysphania ambrosioides (L.) Mosyakin & Clemants in a Cd-spiked soil

Environmental Science and Pollution Research - Soil pollution due to potentially toxic elements is a worldwide challenge for health and food security. Chelate-assisted phytoextraction along with...     

Measurements,Theories and Simulations of Particle Deposits on Super-Heater Tubes in a CFB Biomass Boiler

The present investigation involves theories, simulations and experiments on deposit layers on super-heater tubes in a circulating fluidised bed in Västerås in Sweden. Simulation of particle trajectories in the vicinity of two super-heater tubes is conducted in a Eulerian-Lagrangian mode for the flue gas and the ash particles from the combustion process. Particle impingements on the tubes are investigated for different particle sizes. Measurements of the buildup of deposit layers in the super-heater environment are conducted using a deposit probe. Deposit layer growth and growth rate is analysed for different probe temperatures, as well as the aspect of sintering on the probe ring surface. Analysis of the probe deposit material and deposits from the super-heaters and from textile filters are chemically analysed. The temperature dependence of the deposit materials viscosity is predicted from the chemical analysis of the samples. A model is included to simulate the effect of the deposit layer thickness on the tube heat exchange. The results from the particle trajectory simulations show that particle larger than 10 mm will mainly impinge on the front of the first tube and that smaller particles are more dispersed due to turbulence and thermophorectic forces, enabling a more even impingement on the whole surface of the tubes. The probe deposit layer growth measurements show significant temperature dependence. The deposit material sintering and distribution is proven to be dependent on; temperature, particle size and exposure time. The stickiness of the deposit material is shown to be dependent on the SiO₂ and alkali relation in the samples, estimated through a viscosity model.     

电偶极辐射场的另一种计算方法

研究电偶极辐射问题的出发点是推迟势公式,本文先用格林函数法求解达朗贝尔方程组,得出推迟势公式;再用特殊函数理论对推迟势公式作展开,得出电偶极辐射场,并对远场和近场分别进行讨论。这种计算方法既能对电偶极辐射问题有一个较全面而且准确的认识,又能将数学思想与物理理论相结合,做到学以自用,融会贯通。