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Different land uses have different impacts on the water quality of the region. Multiple isotopes (δD-H2O, δ18O-H2O, δ15N-NO3-, and δ18O-NO3-) and the SIAR (stable isotope analysis in R) model were applied to identify the nitrate sources and estimate the proportional contributions of multiple nitrate sources in a river in a typical urban area (the Grand Canal, Hangzhou) and a river in a typical forest and agricultural area (Yuying Riveri). The results indicated that there were different degrees of nitrogen pollution in the Grand Canal and Yuying River; NO3--N and NH4+-N are the predominant forms of nitrogen in the Grand Canal, and the primary form of nitrogen in Yuying River was NO3--N. There was an obvious linear relationship between the hydrogen and oxygen isotopes (R2=0.78). The δD-H2O and δ18O-H2O values for the Grand Canal and Yuying River were distributed along the local meteoric waterline, indicating that precipitation served as the primary water source in these rivers. All of the δ18O-NO3- values of the Grand Canal and Yuying River were lower than 15 ‰. It was revealed that nitrification, rather than denitrification, was the primary N cycling process in the two rivers. The δ15N-NO3-/δ18O-NO3- ratios of some of the samples from the Grand Canal ranged from 1.3 to 2.1, accompanied by low concentrations of DO and NO2-, indicating that denitrification existed in some sections of the Grand Canal. The δ15N-NO3- values of the samples from the Grand Canal (average:6.1‰) were higher than those from the Yuying River (average:2.3‰). The NO3- source contributions differed significantly between the Grand Canal and Yuying River. The contributions of NO3- sources in the Grand Canal were sewage/manure (37.0%) > soil nitrogen (35.7%) > chemical fertilizer (19.1%) > precipitation (8.2%), and those in the Yuying River were chemical fertilizer (46.1%) > soil nitrogen (22.8%) > precipitation (17.3%) > sewage/manure (13.8%). The contribution of the sewage/manure was substantially increased in the Grand Canal in the urban area with stronger human activities primarily due to the sporadic discharge of domestic sewage and urban runoff. Chemical fertilizer is the main NO3- source in the Yuying River near the forest and agricultural area, suggesting that the nitrogen pollution caused by agricultural non-point sources was extremely serious. The contribution of precipitation decreased in the areas of substantial human activities. The isotopic fractionation produced by denitrification was affected by the contributions of the NO3- sources, which were calculated by SIAR model. Sewage/manure and chemical fertilizer produced significant impacts, followed by soil nitrogen and precipitation.

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OBJECTIVE: This paper is to investigate the effects of steroid or IFN alpha-2b on apoptosis and cell pathway of fibroblasts from keloids, hypertrophic scars and normal skins and different responses of different fibroblasts. METHODS: 6 samples from keloid, hypertrophic scar and normal skin were collected respectively and fibroblasts from different sources were cultured in vitro. After different fibroblasts were treated with dexamethasone (0.1 mg/ml) or IFN alpha-2b (1000 U/ml), Bax and Bcl-2 protein expressions were detected in situ by immunohistochemical staining; DNA ladders of different fibroblasts were observed by gel electrophoresis; and relative activated (phospho-) ERK1/2 and JNK pathways were detected by method of FACE ELISA. RESULTS: Dexamethasone could induce apoptosis of fibroblasts from keloids, hypertrophic scars and normal skins through activating (phospho-) ERK1/2 and JNK pathways; IFN alpha-2b could not induce apoptosis of fibroblasts from different sources. IFN alpha-2b could inhibit (phospho-) ERK1/2 pathway and could not affect (phospho-) JNK pathways of fibroblasts from keloid and hypertrophic scar. IFN alpha-2b could affect neither (phospho-) ERK1/2 pathway nor (phospho-) JNK pathways of fibroblasts from normal skin. CONCLUSIONS: The responses of different fibroblasts to steroid or IFN alpha-2b were different.

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OBJECTIVE: To observe the effect of the early transplantation of double rectus abdominis musculo-cutaneous flaps on the repair of electrical injury of the wrist. METHODS: The study involved six patients suffering from circumferential deep electrical burn with only small amount of normal skin left on the dorsal side. The wounds were covered with double rectus abdominis musculo-cutaneous flaps raised from the upper abdomen with pedicles in both proximal and distal ends at an early postburn stage. The postoperative recovery of wrist function and wound repair were evaluated. RESULTS: The wrist wounds in all the 6 patients were primarily healed, with perfect function and appearance. CONCLUSION: Early application of double rectus abdominis musculocutaneous flaps on the electrically injured wrists can promote the wound healing processes and plays important roles in the preservation of wrist function.

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