Human umbilical cord mesenchymal stem cells,incorporated into an amnion carrier tubes,were assessed for nerve regeneration potential in a rat nerve defect model.Damaged nerves were exposed to human amnion carriers con...Human umbilical cord mesenchymal stem cells,incorporated into an amnion carrier tubes,were assessed for nerve regeneration potential in a rat nerve defect model.Damaged nerves were exposed to human amnion carriers containing either human umbilical cord mesenchymal stem cell (cell transplantation group)or saline(control group).At 8,12,16 and 20 weeks after cell implantation,the sciatic functional index was higher in the cell transplantation group compared with the control group.Furthermore,electrophysiological examination showed that threshold stimulus and maximum stimulus intensity gradually decreased while compound action potential amplitude gradually increased.Hematoxylin-eosin staining showed that regenerating nerve fibers were arranged in nerve tracts in the cell transplantation group and connective tissue between nerve tracts and amnion tissue reduced over time.Gastrocnemius muscle cell diameter,wet weight and restoration ratio were increased.These data indicate that transplanted human umbilical cord mesenchymal stem cells,using the amnion tube connection method,promote restoration of damaged sciatic nerves in rats.展开更多
Aims Vegetation type is important in determining variations in soil carbon(C)efflux under grassland managements.This study was conducted to examine the effects of mowing and nitrogen(N)addition on soil respiration and...Aims Vegetation type is important in determining variations in soil carbon(C)efflux under grassland managements.This study was conducted to examine the effects of mowing and nitrogen(N)addition on soil respiration and their dependences upon vegetation types in an oldfield grassland of northern China.Methods Soil respiration,temperature,moisture and aboveground net primary productivity(ANPP)and belowground net primary productivity(BNPP)were examined in response to mowing and N addition among the three patches dominated by different species(named as grass,forb and mixed patches,respectively)in the growing seasons(May–October)from 2006 to 2008.Important Findings Across the 3 years,soil respiration in the grass patch was greater than those in the forb and mixed patches,which could have been ascribed to the higher soil moisture(SM)in the grass patch.Mowing had no impact on soil respiration due to unaltered SM and plant growth.Soil respiration was stimulated by 6.53%under N addition,and the enhancement was statistically significant in 2006 but not in 2007 or 2008 because of the limited water availability in the later 2 years.There were no interactive effects between mowing and N addition on soil respiration.Soil respiration showed positive dependence upon SM,ANPP and BNPP across plots.The results suggest that soil water availability and plant growth could be the primary factors in controlling the temporal and spatial variations in soil respiration and its response to different treatments.Our observations indicate that grassland managements(i.e.mowing for hay once a year)may have little influence on soil respiration of the oldfield grassland in northern China.展开更多
As safe byproducts of drinking water treatment processes,ferric and alum water treatment residuals(FARs) have the potential to be new phosphate(P) immobilization materials.In this study,batch experiments were conducte...As safe byproducts of drinking water treatment processes,ferric and alum water treatment residuals(FARs) have the potential to be new phosphate(P) immobilization materials.In this study,batch experiments were conducted to investigate and compare the adsorption characteristics of three P species by FARs.The results showed that the kinetic processes of different P species' adsorption by FARs could be described by a pseudo second-order model.The ranking list of the initial adsorption rates with respect to different phosphates was pyrophosphate,phytate,orthophosphate,hexametaphosphate and glycerophosphate.Of the six models considered,the two-site Langmuir model most effectively described the adsorption characteristics of the various P species.Upon fitting the results,the maximum adsorption capacities were determined to be 40.24 mg/g for phytate,18.04 mg/g for pyrophosphate,17.14 mg/g for orthophosphate,15.86 mg/g for hexametaphosphate and 10.81 mg/g for glycerophosphate.In addition,the adsorption processes of the different P species were spontaneous endothermic processes and were favored at lower pH values.The pH dependency was found to be especially true for orthophosphate,where the adsorption capacity decreased by 1.22 mg/g with an increase in pH from 5 to 9.Fractionation of the adsorbed P species from the FARs demonstrated that Al-P and Fe-P were the dominating forms,constituting approximately 80%-90% of the total P fractions,which indicated that the adsorbed P species had a low leaching risk and could stably exist in the FARs.Therefore,the FARs could be effective in controlling pollution in water caused by different P species.展开更多
Fe/Al drinking water treatment residuals(WTRs), ubiquitous and non-hazardous by-products of drinking water purification, are cost-effective adsorbents for glyphosate. Given that repeated glyphosate applications could ...Fe/Al drinking water treatment residuals(WTRs), ubiquitous and non-hazardous by-products of drinking water purification, are cost-effective adsorbents for glyphosate. Given that repeated glyphosate applications could significantly decrease glyphosate retention by soils and that the adsorbed glyphosate is potentially mobile, high sorption capacity and stability of glyphosate in agricultural soils are needed to prevent pollution of water by glyphosate.Therefore, we investigated the feasibility of reusing Fe/Al WTR as a soil amendment to enhance the retention capacity of glyphosate in two agricultural soils. The results of batch experiments showed that the Fe/Al WTR amendment significantly enhanced the glyphosate sorption capacity of both soils(p < 0.001). Up to 30% of the previously adsorbed glyphosate desorbed from the non-amended soils, and the Fe/Al WTR amendment effectively decreased the proportion of glyphosate desorbed. Fractionation analyses further demonstrated that glyphosate adsorbed to non-amended soils was primarily retained in the readily labile fraction(Na HCO3-glyphosate). The WTR amendment significantly increased the relative proportion of the moderately labile fraction(HCl-glyphosate) and concomitantly reduced that of the Na HCO3-glyphosate, hence reducing the potential for the release of soil-adsorbed glyphosate into the aqueous phase. Furthermore, Fe/Al WTR amendment minimized the inhibitory effect of increasing solution p H on glyphosate sorption by soils and mitigated the effects of increasing solution ionic strength. The present results indicate that Fe/Al WTR is suitable for use as a soil amendment to prevent glyphosate pollution of aquatic ecosystems by enhancing the glyphosate retention capacity in soils.展开更多
Batch experiments were conducted to investigate the phosphorus(P)adsorption and desorption on five drinking water treatment residuals(WTRs)collected from different regions in China.The physical and chemical characteri...Batch experiments were conducted to investigate the phosphorus(P)adsorption and desorption on five drinking water treatment residuals(WTRs)collected from different regions in China.The physical and chemical characteristics of the five WTRs were determined.Combined with rotated principal component analysis,multiple regression analysis was used to analyze the relationship between the inherent properties of the WTRs and their P adsorption capacities.The results showed that the maximum P adsorption capacities of the five WTRs calculated using the Langmuir isotherm ranged from 4.17 to8.20 mg/g at a p H of 7 and further increased with a decrease in p H.The statistical analysis revealed that a factor related to Al and 200 mmol/L oxalate-extractable Al(Alox)accounted for 36.5%of the variations in the P adsorption.A similar portion(28.5%)was attributed to an integrated factor related to the p H,Fe,200 mmol/L oxalate-extractable Fe(Feox),surface area and organic matter(OM)of the WTRs.However,factors related to other properties(Ca,P and 5 mmol/L oxalate-extractable Fe and Al)were rejected.In addition,the quantity of P desorption was limited and had a significant negative correlation with the(Feox+Alox)of the WTRs(p<0.05).Overall,WTRs with high contents of Alox,Feoxand OM as well as large surface areas were proposed to be the best choice for P adsorption in practical applications.展开更多
Drinking water treatment residuals(WTRs) have a potential to realize eutrophication control objectives by reducing the internal phosphorus(P) load of lake sediments. Information regarding the ecological risk of dewate...Drinking water treatment residuals(WTRs) have a potential to realize eutrophication control objectives by reducing the internal phosphorus(P) load of lake sediments. Information regarding the ecological risk of dewatered WTR reuse in aquatic environments is generally lacking, however. In this study, we analyzed the eco-toxicity of leachates from sediments with or without dewatered WTRs toward algae Chlorella vulgaris via algal growth inhibition testing with algal cell density, chlorophyll content, malondialdehyde content, antioxidant enzyme superoxide dismutase activity, and subcellular structure indices. The results suggested that leachates from sediments unanimously inhibited algal growth, with or without the addition of different WTR doses(10% or 50% of the sediment in dry weight) at different p H values(8–9), as well as from sediments treated for different durations(10 or 180 days). The inhibition was primarily the result of P deficiency in the leachates owing to WTR P adsorption, however, our results suggest that the dewatered WTRs were considered as a favorable potential material for internal P loading control in lake restoration projects, as it shows acceptably low risk toward aquatic plants.展开更多
Aims Nitrogen(N)enrichment caused by human activities threatens bio-diversity and alters plant community composition and structure.It has been found that heavy and infrequent N inputs may over-estimate species extinct...Aims Nitrogen(N)enrichment caused by human activities threatens bio-diversity and alters plant community composition and structure.It has been found that heavy and infrequent N inputs may over-estimate species extinction,but it remains unclear whether plant community structure will equally respond to frequent reactive N enriched conditions.Methods We independently manipulated the rates and the frequencies of N addition in a temperate steppe,northern China,between 2008 and 2013.Important Findings We found that plant community structure changes,measured by‘Euclidean distance’involving species richness,composition and productivity,were significantly positively related to increasing N enrichment rates rather than frequencies.Changes in aboveground net primary productivity(ANPP),plant species richness and shifts in dominant species were observed.Community ANPP increased with N enrichment,whereas species richness reduced.The frequency of N enrichment increased species richness but had no impacts on community ANPP and the relative ANPP of the two dominant spe-cies,C3 perennial bunchgrass Stipa grandis and C3 perennial rhi-zome grass Leymus chinensis.The ANPP and relative ANPP of the two dominant species were significantly negatively correlated with each other.Moreover,changes in the relative ANPP of S.grandis was negatively associated with the changes in community structure.After 5 years’treatment,direct influence of the frequency of N en-richment on plant community structure was not observed,but the effects of the rate of N enrichment were apparent.Our results sug-gested that further study in various ecosystems and with long-term and well-controlled comparisons the frequency vs.the rate of N enrichment may still be needed.展开更多
在落叶之前,从衰老组织中重新吸收养分被认为是植物适应养分缺乏的一种策略。然而,养分重吸收如何调节植物体内氮(N)和磷(P)的平衡仍不清楚,特别是在土壤氮有效性增加的情况下。本文研究了不同速率(0、1、2、4、8、16、24和32 g N m^(-2...在落叶之前,从衰老组织中重新吸收养分被认为是植物适应养分缺乏的一种策略。然而,养分重吸收如何调节植物体内氮(N)和磷(P)的平衡仍不清楚,特别是在土壤氮有效性增加的情况下。本文研究了不同速率(0、1、2、4、8、16、24和32 g N m^(-2)yr^(-1))氮添加对中国北方盐渍化草地优势植物赖草(Leymus secalinus)叶片和茎秆养分回收的影响,以及养分回收在调控植物内部氮磷平衡的作用。研究结果表明:氮添加6年后,随着施氮量的增加,绿色和衰老组织(叶和茎)的N浓度和氮磷比均呈上升趋势。随着施氮量的增加,绿色组织中P浓度降低,而衰老组织中P浓度无显著变化。N重吸收效率(NRE)、P重吸收效率(PRE)和NRE:PRE比值沿N添加梯度显著降低。此外,我们发现衰老组织(叶和茎)氮磷比比绿色组织(叶和茎)氮磷比对氮素添加的响应更敏感,植物内在氮磷失衡的加剧主要是由于不成比例的减少养分重吸收,尤其是NRE。总的来说,我们的研究表明,NRE和PRE的差异进一步加剧了植物凋落物内部氮磷的失衡。展开更多
基金financially sponsored by the Natural Science Foundation of Liaoning Province,No.20102138
文摘Human umbilical cord mesenchymal stem cells,incorporated into an amnion carrier tubes,were assessed for nerve regeneration potential in a rat nerve defect model.Damaged nerves were exposed to human amnion carriers containing either human umbilical cord mesenchymal stem cell (cell transplantation group)or saline(control group).At 8,12,16 and 20 weeks after cell implantation,the sciatic functional index was higher in the cell transplantation group compared with the control group.Furthermore,electrophysiological examination showed that threshold stimulus and maximum stimulus intensity gradually decreased while compound action potential amplitude gradually increased.Hematoxylin-eosin staining showed that regenerating nerve fibers were arranged in nerve tracts in the cell transplantation group and connective tissue between nerve tracts and amnion tissue reduced over time.Gastrocnemius muscle cell diameter,wet weight and restoration ratio were increased.These data indicate that transplanted human umbilical cord mesenchymal stem cells,using the amnion tube connection method,promote restoration of damaged sciatic nerves in rats.
基金National Basic Research Program(2007CB106803)National Natural Science Foundation of China(30925009).
文摘Aims Vegetation type is important in determining variations in soil carbon(C)efflux under grassland managements.This study was conducted to examine the effects of mowing and nitrogen(N)addition on soil respiration and their dependences upon vegetation types in an oldfield grassland of northern China.Methods Soil respiration,temperature,moisture and aboveground net primary productivity(ANPP)and belowground net primary productivity(BNPP)were examined in response to mowing and N addition among the three patches dominated by different species(named as grass,forb and mixed patches,respectively)in the growing seasons(May–October)from 2006 to 2008.Important Findings Across the 3 years,soil respiration in the grass patch was greater than those in the forb and mixed patches,which could have been ascribed to the higher soil moisture(SM)in the grass patch.Mowing had no impact on soil respiration due to unaltered SM and plant growth.Soil respiration was stimulated by 6.53%under N addition,and the enhancement was statistically significant in 2006 but not in 2007 or 2008 because of the limited water availability in the later 2 years.There were no interactive effects between mowing and N addition on soil respiration.Soil respiration showed positive dependence upon SM,ANPP and BNPP across plots.The results suggest that soil water availability and plant growth could be the primary factors in controlling the temporal and spatial variations in soil respiration and its response to different treatments.Our observations indicate that grassland managements(i.e.mowing for hay once a year)may have little influence on soil respiration of the oldfield grassland in northern China.
基金supported by the National Natural Science Foundation of China (No. 51278055,51179008)
文摘As safe byproducts of drinking water treatment processes,ferric and alum water treatment residuals(FARs) have the potential to be new phosphate(P) immobilization materials.In this study,batch experiments were conducted to investigate and compare the adsorption characteristics of three P species by FARs.The results showed that the kinetic processes of different P species' adsorption by FARs could be described by a pseudo second-order model.The ranking list of the initial adsorption rates with respect to different phosphates was pyrophosphate,phytate,orthophosphate,hexametaphosphate and glycerophosphate.Of the six models considered,the two-site Langmuir model most effectively described the adsorption characteristics of the various P species.Upon fitting the results,the maximum adsorption capacities were determined to be 40.24 mg/g for phytate,18.04 mg/g for pyrophosphate,17.14 mg/g for orthophosphate,15.86 mg/g for hexametaphosphate and 10.81 mg/g for glycerophosphate.In addition,the adsorption processes of the different P species were spontaneous endothermic processes and were favored at lower pH values.The pH dependency was found to be especially true for orthophosphate,where the adsorption capacity decreased by 1.22 mg/g with an increase in pH from 5 to 9.Fractionation of the adsorbed P species from the FARs demonstrated that Al-P and Fe-P were the dominating forms,constituting approximately 80%-90% of the total P fractions,which indicated that the adsorbed P species had a low leaching risk and could stably exist in the FARs.Therefore,the FARs could be effective in controlling pollution in water caused by different P species.
基金supported by the National Natural Science Foundation of China (Nos.51278055, 51179008)the National Key Technology R&D Program (No.2012BAJ21B08)the National Public Benefit (Environmental) Research Foundation of China (No.201109009)
文摘Fe/Al drinking water treatment residuals(WTRs), ubiquitous and non-hazardous by-products of drinking water purification, are cost-effective adsorbents for glyphosate. Given that repeated glyphosate applications could significantly decrease glyphosate retention by soils and that the adsorbed glyphosate is potentially mobile, high sorption capacity and stability of glyphosate in agricultural soils are needed to prevent pollution of water by glyphosate.Therefore, we investigated the feasibility of reusing Fe/Al WTR as a soil amendment to enhance the retention capacity of glyphosate in two agricultural soils. The results of batch experiments showed that the Fe/Al WTR amendment significantly enhanced the glyphosate sorption capacity of both soils(p < 0.001). Up to 30% of the previously adsorbed glyphosate desorbed from the non-amended soils, and the Fe/Al WTR amendment effectively decreased the proportion of glyphosate desorbed. Fractionation analyses further demonstrated that glyphosate adsorbed to non-amended soils was primarily retained in the readily labile fraction(Na HCO3-glyphosate). The WTR amendment significantly increased the relative proportion of the moderately labile fraction(HCl-glyphosate) and concomitantly reduced that of the Na HCO3-glyphosate, hence reducing the potential for the release of soil-adsorbed glyphosate into the aqueous phase. Furthermore, Fe/Al WTR amendment minimized the inhibitory effect of increasing solution p H on glyphosate sorption by soils and mitigated the effects of increasing solution ionic strength. The present results indicate that Fe/Al WTR is suitable for use as a soil amendment to prevent glyphosate pollution of aquatic ecosystems by enhancing the glyphosate retention capacity in soils.
基金supported by the National Key Technology R&D Program(No.2012BAJ21B08)the National Natural Science Foundation of China(No.5127805551179008)
文摘Batch experiments were conducted to investigate the phosphorus(P)adsorption and desorption on five drinking water treatment residuals(WTRs)collected from different regions in China.The physical and chemical characteristics of the five WTRs were determined.Combined with rotated principal component analysis,multiple regression analysis was used to analyze the relationship between the inherent properties of the WTRs and their P adsorption capacities.The results showed that the maximum P adsorption capacities of the five WTRs calculated using the Langmuir isotherm ranged from 4.17 to8.20 mg/g at a p H of 7 and further increased with a decrease in p H.The statistical analysis revealed that a factor related to Al and 200 mmol/L oxalate-extractable Al(Alox)accounted for 36.5%of the variations in the P adsorption.A similar portion(28.5%)was attributed to an integrated factor related to the p H,Fe,200 mmol/L oxalate-extractable Fe(Feox),surface area and organic matter(OM)of the WTRs.However,factors related to other properties(Ca,P and 5 mmol/L oxalate-extractable Fe and Al)were rejected.In addition,the quantity of P desorption was limited and had a significant negative correlation with the(Feox+Alox)of the WTRs(p<0.05).Overall,WTRs with high contents of Alox,Feoxand OM as well as large surface areas were proposed to be the best choice for P adsorption in practical applications.
基金supported by the National Natural Science Foundation of China(No.51278055)the Specialized Research Fund for the Doctoral Program of Higher Education(No.2012003110027)the National Key Technology R&D Program(No.2012BAJ21B08)
文摘Drinking water treatment residuals(WTRs) have a potential to realize eutrophication control objectives by reducing the internal phosphorus(P) load of lake sediments. Information regarding the ecological risk of dewatered WTR reuse in aquatic environments is generally lacking, however. In this study, we analyzed the eco-toxicity of leachates from sediments with or without dewatered WTRs toward algae Chlorella vulgaris via algal growth inhibition testing with algal cell density, chlorophyll content, malondialdehyde content, antioxidant enzyme superoxide dismutase activity, and subcellular structure indices. The results suggested that leachates from sediments unanimously inhibited algal growth, with or without the addition of different WTR doses(10% or 50% of the sediment in dry weight) at different p H values(8–9), as well as from sediments treated for different durations(10 or 180 days). The inhibition was primarily the result of P deficiency in the leachates owing to WTR P adsorption, however, our results suggest that the dewatered WTRs were considered as a favorable potential material for internal P loading control in lake restoration projects, as it shows acceptably low risk toward aquatic plants.
基金National Natural Science Foundation of China(NSFC31570469)+2 种基金China Postdoctoral Science Foundation(2015T80153)to Y.Z.,National Key R&D program of China(2016YFC0500202)N.H.,NSFC(41573063)C.W.and National Key R&D program of China(2016YFC0500700)and NSFC(31430016)to X.H.
文摘Aims Nitrogen(N)enrichment caused by human activities threatens bio-diversity and alters plant community composition and structure.It has been found that heavy and infrequent N inputs may over-estimate species extinction,but it remains unclear whether plant community structure will equally respond to frequent reactive N enriched conditions.Methods We independently manipulated the rates and the frequencies of N addition in a temperate steppe,northern China,between 2008 and 2013.Important Findings We found that plant community structure changes,measured by‘Euclidean distance’involving species richness,composition and productivity,were significantly positively related to increasing N enrichment rates rather than frequencies.Changes in aboveground net primary productivity(ANPP),plant species richness and shifts in dominant species were observed.Community ANPP increased with N enrichment,whereas species richness reduced.The frequency of N enrichment increased species richness but had no impacts on community ANPP and the relative ANPP of the two dominant spe-cies,C3 perennial bunchgrass Stipa grandis and C3 perennial rhi-zome grass Leymus chinensis.The ANPP and relative ANPP of the two dominant species were significantly negatively correlated with each other.Moreover,changes in the relative ANPP of S.grandis was negatively associated with the changes in community structure.After 5 years’treatment,direct influence of the frequency of N en-richment on plant community structure was not observed,but the effects of the rate of N enrichment were apparent.Our results sug-gested that further study in various ecosystems and with long-term and well-controlled comparisons the frequency vs.the rate of N enrichment may still be needed.
基金This work Was supported by Chinese National Key Research and Development Program for Basic Research(2017YFA0604802)the National Natural Science Foundation of China(31770526,31872406and 31800402)the Research projects of Shanxi Province's doctoral graduates and postdoctoral researchers working in Shanxi Province(SXBYKY2021052).
基金supported by the Chinese National Key Development Program for Basic Research(grant no.2017YFA0604802 and 2016YFC0500703)National Natural Science Foundation of China(grant no.31770526 and 41573063)+1 种基金Strategic Priority Research Program on Soil and Microbes of the Chinese Academy of Sciences(grant no.XDB15010401)Key Laboratory of Vegetation Ecology,Ministry of Education.X.X.acknowledges the financial support from the San Diego State University and the CSU Program for Education&Research in Biotechnology.
基金This work was supported by National Natural Science Foundation of China(31770526,31872406)the Chinese National Key Development Program for Basic Research(2016YFC0500703).
基金This work was supported by National Natural Science Foundation of China(32371670)the High-Level Talents Project of Shanxi Agricultural University(2021XG008)+1 种基金Award Fund for Work of Excellent Researchers in Shanxi Province(SXBYKY2022042)Science and Technology Innovation Foundation of Shanxi Agricultural University(2021BQ64).
文摘在落叶之前,从衰老组织中重新吸收养分被认为是植物适应养分缺乏的一种策略。然而,养分重吸收如何调节植物体内氮(N)和磷(P)的平衡仍不清楚,特别是在土壤氮有效性增加的情况下。本文研究了不同速率(0、1、2、4、8、16、24和32 g N m^(-2)yr^(-1))氮添加对中国北方盐渍化草地优势植物赖草(Leymus secalinus)叶片和茎秆养分回收的影响,以及养分回收在调控植物内部氮磷平衡的作用。研究结果表明:氮添加6年后,随着施氮量的增加,绿色和衰老组织(叶和茎)的N浓度和氮磷比均呈上升趋势。随着施氮量的增加,绿色组织中P浓度降低,而衰老组织中P浓度无显著变化。N重吸收效率(NRE)、P重吸收效率(PRE)和NRE:PRE比值沿N添加梯度显著降低。此外,我们发现衰老组织(叶和茎)氮磷比比绿色组织(叶和茎)氮磷比对氮素添加的响应更敏感,植物内在氮磷失衡的加剧主要是由于不成比例的减少养分重吸收,尤其是NRE。总的来说,我们的研究表明,NRE和PRE的差异进一步加剧了植物凋落物内部氮磷的失衡。
