Polyvinyl acetate-based soil stabilization for rock slope ecological restoration.

External-soil spray seeding (ESSS) is a method often used for the ecological restoration of bare rock slopes. However, the direct use of ESSS is normally less satisfactory due to the erosion of sprayed soil and low survival rate of the plants on rock slopes. This study proposes a novel approach to addressing this issue through the combined use of ESSS with polyvinyl acetate (PVA) based soil stabilization. The PVA solutions are added to the soil to stabilize soil and improve soil strength while possessing high water and nutrient retention favorable for plant growth. A series of experimental tests on the mechanical properties, water stability, erosion resistance, water retention, and plant growth of the PVA-stabilized soil were conducted to assess the efficacy of the proposed method. The results showed that the proposed method could be promising for rock slope ecological restoration. A proper curing time (e.g., >3 days) was required to achieve beneficial effects of PVA on the soil properties. A shorter curing time would otherwise result in the decrease in the strength with the increased PVA content. It was found that the optimum PVA content was 3% for achieving the maximum water stability, erosion resistance, water retention, and plant growth. The cohesion increased by up to 50% and the internal friction angle increased by 3.5° compared to the natural soil. The disintegration rate of the stabilized soil was generally < 3e-3%/min. The maximum reduction in erosion was up to 83% when the PVA content ≥3%. The mechanisms behind the findings are also discussed.

Structural Transformation Pathways of Alkaline Earth Family Coordination Polymers Containing 3,3',5,5'-Biphenyl Tetracarboxylic Acid.

The understanding of crystal stepwise transformation is very important to enclose the "black box" in the preparation of crystal materials. In this work, different structural intermediates were isolated prior to the formation of the final alkali earth coordination polymers (CPs) during the preparation of three pairs of alkali earth CPs through solvothermal method and convenient oil-bath reactions. Single crystal X-ray diffraction analysis demonstrated the structural transformation from a 0 D to 1 D inorganic connectivity for the Ca-CPs and Sr-CPs, but a 1 D to 0 D inorganic connectivity for Ba-CPs, involving the breakage/formation of chemical bonds in the reaction solutions. Further analyses indicated that these two different structural transformation pathways are determined by the deprotonation of organic acid, competitive balance between the inorganic and organic connectivity, and the twist of the linker. FT-IR spectra, thermogravimetric and luminescence behaviors agree with their structural characteristics.

DACT1 is involved in human placenta development by promoting Wnt signaling.

OBJECTIVE: The aim of this study was to evaluate the expression of DACT1 in human placenta tissue and the relationship between DACT1 and target genes of the Wnt signaling pathway. METHOD: Real-time PCR and western blotting were used to detect the expression of DACT1 and the target genes of Wnt signaling pathway in human placenta tissue. And the relationship between them was analyzed using SPSS 19. RESULTS: Real-time PCR results showed that DACT1 expression was significantly higher in 49- to 71-day placenta tissues (mean value = 0.020) than that in 39- to 48-day (the mean value = 0.009). The mRNA expressions of the Wnt signaling pathway target genes, CCND1, CCND2, FOSL1, DAB2 and JUN, were also increased expressed in human placenta tissues. Significant positive associations between DACT1 and CCND1, CCND2, FOSL1, DAB2 and JUN were observed. Western blotting analysis showed that the protein expression of DACT1, CCND1, CCND2, FOSL1, DAB2 and JUN displayed the increasing trend in 43-, 49- and 71-day placenta samples. CONCLUSION: DACT1 might play an important role in human placenta development via promoting Wnt signaling.

[Seasonal variation of bioavailable phosphorus in sediments in northeast part of Taihu Lake].

The concentrations of total phosphorus (TP), bioavailable phosphorus (BAP) and their seasonal changes in the surface sediments (0-10 cm) from three different regions of northeast of Taihu Lake were investigated. The results show that the concentrations of TP and BAP in the sediment are coincided with the corresponding trophic level of the overlying water. The concentrations of TP and BAP in the sediments varied widely not only between sampling sites but also between seasons. There is a significant correlation between BAP and TP in surface sediments, and their regression analysis equation varies with seasons. It is suggested to evaluate potential phosphorus-release risk of the sediment based on the TP concentration of the corresponding seasons.

[Structure and ecological environmental efficiency of urban forestation].

It is proposed that a new pattern of forestation, arbor-shrub-lawn composite construction, based on analyzing the form and the actual state of the urban forestation. The arbor-shrub-lawn is superior by comparing with the urban lawn as for ecological environmental function including landscape. It is suggested that forestation's ecological saving efficiency and management, maintaining and reducing cost should be thought over simultaneously.