Background Relatively few studies have been made on neurobehavioral outcomes of prenatal maternal stress during the newborn period, and little research has focused on umbilical cord stress hormones including cortisol, adrenocorticotropic hormone (ACTH), norepinephrine, and epinephrine. Our objective was to investigate the effects of prenatal maternal life stressors on neonatal birth outcomes, neurobehavioral development, and stress-related hormones levels. Methods Participants were 142 mothers and their infants; 71 were selected as the prenatal life stressor exposed group and 71 as the control group matched on maternal age, gestational week, delivery type, socioeconomic and education status, and newborns' sex. Maternal life stressors during pregnancy were determined using the Life Events Scale for Pregnant Women. Neonatal neurobehavioral development was assessed with the Neonatal Behavioral Neurological Assessment. Umbilical cord plasma stress-related hormones, including ACTH, cortisol, norepinephrine, and epinephrine were measured using an enzyme-linked immunosorbent assay. Results In the prenatal life stressors exposed group, newborns had significantly lower birth weight, smaller head circumference (p < 0.01, p < 0.01, respectively). Scores of Neonatal Behavioral Neurological Assessment were significantly reduced (p < 0.001). Cord plasma ACTH, norepinephrine, and epinephrine levels were significantly increased (p < 0.001), but cortisol levels were reduced (p < 0.001). Conclusion Prenatal maternal stress may negatively affect fetal birth outcomes, neurobehavioral development and affect neonates' cord plasma ACTH, cortisol, norepinephrine, and epinephrine.

Three problems remained to be solved in the analysis of the seismic stability of high-fill embankment:the pseudo-static method was defective, the embankment damage model was not clear, and the stability evaluation index wasstill to be discussed. It analyzed the dynamic response of a typical transect of high embankment with FEM to find out its instability mechanism. Thenit chose the most dangerous sliding surface and analyzed its stability. The selection of the evaluation index of the seismic stability of high-fill embankment was discussed at last. The results show thatthe upper embankment, especially the shoulder is easily to be damaged. It is too conservative to use the safety factor as the involution index of the seismic stability of high-fill embankment, and the permanent displacement is a better choice.

Subway shield lining segments are highly sensitive to peripheral soil disturbance. Shield displacement may destroy the whole structure which can not be repaired, and directly affects the subway operation safety at the worst. Therefore, it is necessary to reasonably determine the construction technology, in order to avoid the unfavorable influences caused by construction disturbance. According to the pile-board subgrade scheme which is adopted by the comparison of schemes, also considering the high risk of over-shallow-embedded metro construction, we put forward the key construction technique of pile-board subgrade, including: technique of casing tube bored pile, construction process of pile-board structure and monitoring of settlement and deformation which are important to guide the similar projects.

The paper took Taiyuan-Zhongwei-Yinchuan Railway as a background and the study focused on the frost damage there. First of all, the influence on the line operation was mentioned, discussing the status quo and the characteristics of the damage; next, by means of on-site investigation and testing, the phenomenon in the typical frost damage zone along the Railway was analyzed with the damages being classified; simultaneously, taking the track bed and the subgrade bed as the objectives, the damages were studied from the aspect of soil, water and temperature; last, the genesis and mechanism of the frost damage to the Lanzhou-Xinjiang Railway subgrade was generalized, offering the basis of the treatment.

Lanzhou-Xinjiang passenger dedicated line is the first high speed railway on china's northwestern Gobi where the temperature range is large and the wind is huge. Most road section of Lan-Xin passenger dedicated line is subgrade. This paper researches the ballastless track subgrade settlement observation scheme and assessment method on area where climatic conditions is harsh and geologic conditions is complex. The result shows that: the observation accuracy of subgrade settlement tests satisfies the requirement by using Layered settlement instrument, intelligent static force level and high-accuracy Hydraulic settlement instrument; Subgrade lies upon bedrock or Gobi soil with great bearing capacity in gale area, and distance between observation sections could be increased seemly. The space between observation sections generally should be less than 100m in areas where bedrock exposed, thick gravel soil distribute commonly; the distance between observation sections should be less than 50m in pre-mountain Alluvial-pluvial plain areas; hyperbolic method adapt the estimate of subgrade settlement on Gobi area, and the correlation coefficient is 0.97; Subgrade settlement deformation curve converges quickly and the settlement value after 40 days reaches 85% of ultimate settlement.

The criterion for residual deformation of Substructure of ballasteless track on railway passenger dedicated line is extremely strict in order to satisfy the safety and comfort requirements of the high-speed train during operation period, urgent need to strengthen the ballastless track lines settlement deformation observation, prediction and assessment technology. Based on Chengdu-Guanxian line, this paper puts forward observation programs of subgrade settlement combined with the characteristics of Subgrade Settlement through the analysis of the influence factors of subgrade settlement deformation and key consideration about the factors of nighttime observation precision. It shows that the monitoring and assessment technology could meet the requirements through the analysis of field data, it can be guidance of railway management departments to make maintenance plan. Some advices provide reference for the monitoring and assessment of high-speed railway subgrade settlement during operation period.

To investigate the effect of foundation slope on stability of embankment upon the slope in permafrost area, 3 groups of model tests with different foundation slope are designed using the mechanical similarity based on geotechnical centrifuge modeling, when the freezing-thawing depth of the embankment reaches the greatest. The results show that: (1) The foundation slope has effect on the stability of the embankment. The deformation mainly concentrates on the soil layers above the freezing-thawing interface, and the deformation mutation point takes place at the freezing-thawing interface. (2) According to fracture characteristics and failure severity of the embankment, failure modes can be divided into the cracking failure in shallow layer and in deep layer. (3) The cause of unstable failure is the deficiency of shear resistance strength of the weak belt, the soil layers above the freezing-thawing interface slips along the freezing-thawing interface under gravity load. (4) Under the experimental conditions, the critical value of the foundation slope influencing on the stability of the embankment is about 1:6 when the height of the slope embankment is 5.0 m.