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Xudong Dong,1,2,&ast; Ailing Ding,2,&ast; Hong Hu,1 Fanping Xu,1 Lingyan Liu,1 Min Wu1,3 1The Obstetrical Department of the First People’s Hospital of Yunnan Province, The Affiliated Hospital of Kunming University of Science and Technology, Kunming, 650500, People’s Republic of China; 2Faculty of Life Science and Technology, Kunming University of Science & Technology, Kunming, 650500, People’s Republic of China; 3Yunnan Provincial Key Laboratory of Carbon Sequestration and Pollution Control in Soils, Faculty of Environmental Science & Engineering, Kunming University of Science & Technology, Kunming, 650500, People’s Republic of China&ast;These authors contributed equally to this workCorrespondence: Min Wu, Email minwupp@163.comPurpose: As two of the most severe and common medical disorders during pregnancy, gestational diabetes mellitus (GDM) and hypertensive disorder complicating pregnancy (HDCP) cause adverse effects on placental barrier function and thus may lead to a high risk of intrauterine exposure to toxic metals from mother to fetus. This study investigates the impact of the placental barrier on the transfer of cadmium (Cd) from mother to fetus and the relationship between pregnancy complications.Methods: A total of 107 pairs of samples were collected in Kunming, China; 29 were from healthy pregnant women, and 78 were from patients with pregnancy complications. Cd was measured in each mother’s placenta and maternal and umbilical cord blood. The expressions of MT and Cd-MT complex in blood and placental tissue samples were determined by enzyme-linked immunosorbent assay (ELISA).Results: The cesarean section rate in the whole pathological group (60.7%) was higher than that in the normal group (20.7%), and the ratio of the effective barrier (ratio of maternal blood to umbilical cord blood> 1) in the pathological group (74%) was lower than that in the normal group (79%). In addition, the proportion of practical placental barriers in women aged 20– 25 years was 83.3%, 76.3% in women aged 26– 30 years, 74.3% in women aged 31– 35 years, 70% in women aged 36– 40 years, and 71% in women aged 40– 45 years. The Cd content in the placenta of the three pathological groups was significantly higher than that in maternal and umbilical cord blood (P< 0.05), and the distribution of Cd was the same as that in the normal group. However, there was no significant difference between maternal and umbilical cord blood Cd concentrations in the pathological group. The Cd concentration in the normal group’s maternal blood was significantly higher than that in cord blood (P< 0.05). In addition, the expression levels of both metallothionein (MT) and Cd-MT complex in placenta is much higher than in maternal and umbilical blood, and which in normal group are significantly higher than those in pathological group.Conclusion: Both mothers and fetuses are at increased health risk for pregnancy disorders when maternal age, BMI, or body weight increases. Increased maternal age increases the likelihood of Cd transfer from the mother to the fetus. Pregnancy complications may induce lower expression of MT, thus reducing the Cd-MT complex in the placenta, weakening the placental barrier, and increasing the risk of Cd transfer and exposure to the fetus.Keywords: gestational diabetes mellitus, gestational hypertension, maternal blood, placenta barrier, pregnancy complication

Due to well-developed natural fractures, tight oil reservoirs always described as stress sensitive dual media reservoir. So far, the pressure distribution model for multi-stage fractured horizontal well (MFW) in stress sensitive reservoir is almost solved by numerical method. This paper gives the semi-analytical solution to this problem. Firstly, with consideration of stress sensitivity, a transient pressure behavior model of MFW was established. Using perturbation transform, Laplace transform, image theory and superposition principle the mathematical model was solved. Finally, by applying stehfest numerical inversion and perturbation inverse transform, we get the transient pressure for MFW in the time domain. According to the result of calculation, the flow process of MFW can be identified as six regimes: Ⅰ linear flow, Ⅱ the first radial flow, Ⅲ double radial flow, Ⅳ radial flow in the natural fractures system, Ⅴ cross flow, Ⅵ radial flow in the entire reservoir. Stress-sensibility primarily influences the latter five stages. The well bore dimensionless pressure drop is several times larger comparing with the situation that don't take the stress sensitive into account, and the dimensionless pressure drop derivative curve will tilte up in the later flow process, showing the characteristic of closed boundary. Accordingly, the calculating error will be larger and can mislead the interpretation of well testing.

Whether qualitative or quantitative, whether macroscopic or microscopic, Predecessors' research on the sealing ability of caprocks is concentrated on the static model of the caprock. A few scholars have also proposed the sealability evaluations of the caprock dynamic evolution process, they are all aimed at the dynamic evolution of geological historical periods, and there are few studies on the sealability of gas storage caprocks under periodic injection and production. In this paper, the characteristics of stress and strain under alternating loads of rock and non-rock materials are investigated and experimentally studied to clarify the law of fatigue failure of gas storage caprocks under periodic injection-production. The results show that it is possible that the microcracks may develop and propagate in the rock after the gas storage has experienced many periodic injections and productions, when the stress is far less than the rock strength limit, And then a macroscopic deformation is formed. The accumulated plastic deformation of the rock will increase, and the plastic deformation rate will gradually decrease, as the number of injection and production increases.

Rare earth conversion coating is one of the most promising substitutes to the toxic chromate coating. The corrosion resistance of lanthanum conversion coating modified with citric acid on hot dip galvanized (HDG) steel was investigated in aerated 1 M NaCl solution by means of electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization measurements. Equivalent circuits were subsequently developed from the measurements to elucidate the corrosion behavior of the coating. The surface morphology of the lanthanum conversion coating was observed by scanning electron microscopy (SEM), and the chemical composition of the coating was characterized by energy dispersive spectroscopy (EDS). The results showed that the corrosion process of the modified lanthanum conversion coating consisted of three stages. The overall corrosion resistance of the coating was excellent.