Adapting the RUSLE and GIS to model soil erosion risk in a mountains karst watershed, Guizhou Province, China.

Soil erosion is a serious environmental problem in Guizhou Province, which is located in the centre of the karst areas of southwestern China. Unfortunately, Guizhou Province suffers from a lack of financial resources to research, monitor and model soil erosion at large watershed. In order to assess the soil erosion risk, soil erosion modeling at the watershed scale are urgently needed to be undertaken. This study integrated the Revised Universal Soil Loss Equation (RUSLE) with a Geographic Information System (GIS) to estimate soil loss and identify the risk erosion areas in the Maotiao River watershed, which is a typical rural watershed in Guizhou Province. All factors used in the RUSLE were calculated for the watershed using local data. It was classified into five categories ranging from minimal risk to extreme erosion risk depending on the calculated soil erosion amount. The soil erosion map was linked to land use, elevation and slope maps to explore the relationship between soil erosion and environmental factors and identify the areas of soil erosion risk. The results can be used to advice the local government in prioritizing the areas of immediate erosion mitigation. The integrated approach allows for relatively easy, fast, and cost-effective estimation of spatially distributed soil erosion. It thus indicates that RUSLE-GIS model is a useful and efficient tool for evaluating and mapping soil erosion risk at a large watershed scale in Guizhou Province.

Effect of hemodialysis with plasma-based dialysate plus high volume hemofiltration on plasma cytokines in patients with liver failure / 中华肾脏病杂志

Objective To propose a new blood purification modality-hemodialysis with plasma- based dialysate (HD-PBD) plus high volume hemofiltration (HVHF) for patients with liver failure, and to evaluate the effect of this treatment on plasma cytokines.Methods Twelve patients with liver failure were included in this study.All patients received HD-PBD therapy in the first 6 hours,and then were treated with HVHF for 24 hours with the same filter (AV600).The levels of TNF-?,IL-1?, IL-6 and IL-8 in plasma before and after HD-PBD plus HVHF for 6 and 24 hours were examined respectively by ELISA,and changes of clinical parameters were observed at the same time point. Serum bilirubin,total bile acids (TBA),serum ammonia,blood urea nitrogen (BUN) and serum creatinine (Scr) were detected before and after treatment.Arterial blood gas analysis and the concentration of electrolytes were monitored before and after treatment.Results (1)HD-PBD for 6 hours was more effective than HVHF for 24 hours in removal of serum bilirubin and TBA(P＜0.05). (2)Serum ammonia,BUN,Ser,arterial blood HCO_3~-,PCO_2,PO_2 and electrolytes did not show significant difference before and after HD-PBD (P＞0.05),but these parameters significantly changed before and after HVHF (P＜0.05).(3)The average level of serum bilirubin was sharply decreased after HVHF for 24 h following HD-PBD(P＜0.05).(4)After HD-PBD plus HVHF,there was a marked reduction of the plasma levels of TNF-?,IL-6 and IL-8.Conclusions HD-PBD plus HVHF,a newly proposed modality for patients with liver failure,can effectively decrease serum bilirubin,TBA,BUN,Scr,ammonia and cytokines,and adjust water-electrolyte as well as acid- alkali balance.It is a low-cost,safe,simple and convenient therapy.