No abstract

Heavy metal pollution is a widespread problem and strongly affects human health through the food chain. In this study, the overall pollution situation and source apportionment of heavy metals in soil (Hg, Cd, As, Pb, Ni, Zn, Cu and Cr) were evaluated using various methods including geo-accumulation index (I geo), potential ecological risk index (RI) and positive matrix factorization combined with Geographical Information System (GIS) to quantify and identify the possible sources to these heavy metals in soils. The results of I geo showed that this farmland top soil moderate contaminated by Hg, other selected elements with noncontamination level. And the average RI in the top soil was 259.89, indicating a moderate ecological risk, of which Hg and Cd attributed 88.87% of the RI. The results of the PMF model showed that the relative contributions of heavy metals due to atmospheric depositions (18.70%), sewage irrigations (21.17%), soil parent materials (19.11%), industrial and residential coal combustions (17.43%) and agricultural and lithogenic sources (23.59%), respectively. Of these elements, Pb and Cd were came from atmospheric deposition. Cr was attributed to sewage irrigations. As was mainly derived from the soil parent materials. Hg originated from industrial and residential coal combustions, and most of the Cu, Zn and Ni, except for Pb, were predominantly derived from agricultural and lithogenic sources. These results are important in considering management plans to control the aggravation of heavy metal pollution and ultimately to protect soil resources in this region. In addition, this study enhances the understanding of heavy metal contamination occurrence in agroecosystem that helps predicting and limiting the potential of heavy metal exposure to people and ecosystem.

In this study, the whey protein of fresh mare's milk was used as raw material. The antioxidant peptide liquid XMNDT was extracted from fresh mare's milk solution and purified. The peptide had a molecular weight of 1594.89 kDa and was mainly composed of VAPFPQPVVPYPQR. Antioxidant peptide XMNDT could inhibit the proliferation of A549 lung cancer cells in the G1 phase, accelerate cell apoptosis, increase the activity of SOD and the amount of GSH, and reduce the secretion of MDA. It also exhibited certain antioxidant capacity and free radical scavenging. These data can provide a basis for research on new antioxidant properties by reducing the inflammation caused by aging.

Land degradation and desertification are the great concern of arid and semiarid areas. In Euphrates poplar forest, there exists large number of bare spots which have been considered as representative of desertification. In this study, Unmanned Aerial Vehicle (UAV) technology was used to determine the spatial distribution and extract the bare spots area and morphological characteristics of Populus euphratica stands. Besides, the physical and chemical properties between soils inside and outside of these spots were compared. We found that: (1) the UAV method could be reliably used to extract the area of bare spots and the morphological characteristics of Populus euphratica stands;(2) with Pearson correlation coefficients of 0.673 and 0.894, there were a strong correlation relationship between bare spots area and canopy area in both measured and estimated data rather than other morphological characteristics;(3) electrical conductivity, pH, soil water content, total nitrogen, total phosphorus and soil organic matter has great differences between soils inside and outside of bare spots. These results not only could contribute to further understanding of spatial distribution of bare spots, but also helps to the sustainable management of Populus euphratica forest in arid regions.