BACKGROUND Hypertension is prevalent in the general population and is regarded as the second leading cause of renal damage and dysfunction,outnumbered only by diabetes.However,the mechanisms remain unclear.AIM To inve...BACKGROUND Hypertension is prevalent in the general population and is regarded as the second leading cause of renal damage and dysfunction,outnumbered only by diabetes.However,the mechanisms remain unclear.AIM To investigate podocyte injury induced by hypertension in the early course without massive proteinuria or renal dysfunction.METHODS The hypertension group comprised 18 patients with hypertension accompanied by microalbuminuria,diagnosed with hypertensive renal injury according to biopsy results.For a comparison of pathological changes in renal tissue,control group 1 comprised 10 healthy volunteers,and control group 2 comprised 16 patients who underwent surgery for renal trauma.RESULTS The hypertension group had significantly higher blood pressure(P=0.000)and microalbuminuria(P=0.000)compared with control group 1.In the hypertension group,urinary podocytes were detected following positive staining of podocytespecific nephrin and/or CD2-associated protein(CD2AP)in urine sediment.Podocyte foot process fusion and a significant decrease in nephrin and/or CD2AP expression in glomeruli were observed in the hypertension group compared with control group 2.This indicated that hypertension caused podocyte injury and detachment from the glomerular basement membrane,which was consistent with urinary detection of podocytes.CONCLUSION Our results suggest that podocyturia appears early in the course of hypertensive renal injury,and may be a sensitive marker for early prediction of hypertensive renal injury.展开更多
Compared with retail prices of state-owned companies used in almost all existing studies,China’s refined oil wholesale prices of private enterprises and local refineries are more affected by the market and better ref...Compared with retail prices of state-owned companies used in almost all existing studies,China’s refined oil wholesale prices of private enterprises and local refineries are more affected by the market and better reflect the real supply-demand situation.For the first time,this paper applies own-monitored dailyfrequency wholesale prices of China’s private enterprises and local refineries during 2013-2020 to derive spillover effects of international crude oil prices on China’s refined oil prices through the VAR-BEKKGARCH(vector autoregression-Baba,Engle,Kraft,and Kroner-generalized autoregressive conditional heteroscedasticity)model,and then tries to forecast wholesale prices through the PCA-BP(principal component analysis-back propagation)neural network model.Results show that international crude oil prices have significant mean spillover and volatility spillover effects on China’s refined oil wholesale prices.Changes in crude oil prices are the Granger cause of changes in refined oil wholesale prices.With the improvement of China’s oil-pricing mechanism in 2016,the volatility spillover from the international crude oil market to China’s refined oil market gradually increases,and the BRENT price variation has an increasing impact on the refined oil wholesale price variation.The PCA-BP model could serve as a candidate tool for forecasting China’s refined oil wholesale prices.展开更多
The role of hydrogen in the transition to carbon-neutral energy systems will be influenced by key factors such as carbon neutrality pathways,hydrogen production technology costs,and hydrogen transportation costs.Exist...The role of hydrogen in the transition to carbon-neutral energy systems will be influenced by key factors such as carbon neutrality pathways,hydrogen production technology costs,and hydrogen transportation costs.Existing studies have not comprehensively analyzed and compared the impact of these key factors on the development of hydrogen supply and demand under China's carbon neutrality pathways.This study uses the Global Change Assessment Model(GCAM)with an upgraded hydrogen module to evaluate the development potential of China's hydrogen industry,considering various carbon neutrality pathways as well as hydrogen production and transportation costs.The findings indicate that,by 2050,hydrogen could account for 8%-14%of final energy,averting 1.0-1.7 Bt of carbon emissions annually at an average mitigation cost of 85-183 USD t^(-1) CO_(2).The total hydrogen production is projected to reach 75-135 Mt,with 34%-56%from renewable energy electrolysis and about 15%-29%from fossil fuel-based CCS.On a sectoral level,by 2050,the hydrogen demand in the industrial and transportation sectors is expected to reach 37-63 Mt and 30-42 Mt,with a potential reduction of about 0.6-0.9 BtCO_(2) and 0.5-0.6 BtCO_(2).The share of hydrogen in the final energy of the steel and chemical sectors is estimated to be 9%-19%and 17%-25%,collectively accounting for 36%-42%of total hydrogen demand and 46%-50%of total emission reduction potential.Realizing hydrogen's emission reduction potential relies on the rapid development of hydrogen production,transportation,and utilization technologies.Firstly,the development of on-site electrolysis for hydrogen production and early deployment of industrial hydrogen applications should be prioritized to stimulate overall growth of hydrogen industry and cost reduction.Secondly,vigorous development of renewable energy electrolysis and hydrogen end-use technologies like fuel cells should be pursued,along with the demonstration and promotion of hydrogen transportation technologies.Lastly,further advancement of carbon market mechanisms is essential to support the widespread adoption of hydrogen technologies.展开更多
Objective To isolate and identify bioactive constituents from the stem barks of I//icium difengpi. Methods The chemical constituents were isolated and purified by repeated silica gel, Sephadex LH-20, recrystallization...Objective To isolate and identify bioactive constituents from the stem barks of I//icium difengpi. Methods The chemical constituents were isolated and purified by repeated silica gel, Sephadex LH-20, recrystallization, and preparative HPLC techniques. The structures of the compounds were identified on the basis of spectral data including NMR, MS, and IR. Results Two sesquiterpene lactones, majucin （I） and anisatin （2）, two steroids, l^-sitosterol （3） and daucosterol （4）, three carboxylic acids, 2-ethyldecanoic acid （5）, shikimic acid （6）, and 3,4-dihydrobenzoic acid （7）, and a flavonoid, quercetin （8）, were successively isolated from the stem barks of L difengpL Conclusion Apart from compound 3, other seven compounds are reported in this plant for the first time. The results suggested that the current studies on L difengpi is still far from being well known and therefore more studies need to be done for better understanding of this plant.展开更多
基金Supported by the Natural Science Foundation of Liaoning Provincial Department of Science and Technology,No.2017225020
文摘BACKGROUND Hypertension is prevalent in the general population and is regarded as the second leading cause of renal damage and dysfunction,outnumbered only by diabetes.However,the mechanisms remain unclear.AIM To investigate podocyte injury induced by hypertension in the early course without massive proteinuria or renal dysfunction.METHODS The hypertension group comprised 18 patients with hypertension accompanied by microalbuminuria,diagnosed with hypertensive renal injury according to biopsy results.For a comparison of pathological changes in renal tissue,control group 1 comprised 10 healthy volunteers,and control group 2 comprised 16 patients who underwent surgery for renal trauma.RESULTS The hypertension group had significantly higher blood pressure(P=0.000)and microalbuminuria(P=0.000)compared with control group 1.In the hypertension group,urinary podocytes were detected following positive staining of podocytespecific nephrin and/or CD2-associated protein(CD2AP)in urine sediment.Podocyte foot process fusion and a significant decrease in nephrin and/or CD2AP expression in glomeruli were observed in the hypertension group compared with control group 2.This indicated that hypertension caused podocyte injury and detachment from the glomerular basement membrane,which was consistent with urinary detection of podocytes.CONCLUSION Our results suggest that podocyturia appears early in the course of hypertensive renal injury,and may be a sensitive marker for early prediction of hypertensive renal injury.
基金the financial support from the Science Foundation of China University of Petroleum,Beijing(2462020YXZZ038)
文摘Compared with retail prices of state-owned companies used in almost all existing studies,China’s refined oil wholesale prices of private enterprises and local refineries are more affected by the market and better reflect the real supply-demand situation.For the first time,this paper applies own-monitored dailyfrequency wholesale prices of China’s private enterprises and local refineries during 2013-2020 to derive spillover effects of international crude oil prices on China’s refined oil prices through the VAR-BEKKGARCH(vector autoregression-Baba,Engle,Kraft,and Kroner-generalized autoregressive conditional heteroscedasticity)model,and then tries to forecast wholesale prices through the PCA-BP(principal component analysis-back propagation)neural network model.Results show that international crude oil prices have significant mean spillover and volatility spillover effects on China’s refined oil wholesale prices.Changes in crude oil prices are the Granger cause of changes in refined oil wholesale prices.With the improvement of China’s oil-pricing mechanism in 2016,the volatility spillover from the international crude oil market to China’s refined oil market gradually increases,and the BRENT price variation has an increasing impact on the refined oil wholesale price variation.The PCA-BP model could serve as a candidate tool for forecasting China’s refined oil wholesale prices.
基金supported by Science and Technology Project of SGCC(Key Technology Research and Application of Multi-Regional Collaborative Emission Reduction Simulation Considering Interprovincial Carbon Emission Transfer,1400-202357320A-1-1-ZN).
文摘The role of hydrogen in the transition to carbon-neutral energy systems will be influenced by key factors such as carbon neutrality pathways,hydrogen production technology costs,and hydrogen transportation costs.Existing studies have not comprehensively analyzed and compared the impact of these key factors on the development of hydrogen supply and demand under China's carbon neutrality pathways.This study uses the Global Change Assessment Model(GCAM)with an upgraded hydrogen module to evaluate the development potential of China's hydrogen industry,considering various carbon neutrality pathways as well as hydrogen production and transportation costs.The findings indicate that,by 2050,hydrogen could account for 8%-14%of final energy,averting 1.0-1.7 Bt of carbon emissions annually at an average mitigation cost of 85-183 USD t^(-1) CO_(2).The total hydrogen production is projected to reach 75-135 Mt,with 34%-56%from renewable energy electrolysis and about 15%-29%from fossil fuel-based CCS.On a sectoral level,by 2050,the hydrogen demand in the industrial and transportation sectors is expected to reach 37-63 Mt and 30-42 Mt,with a potential reduction of about 0.6-0.9 BtCO_(2) and 0.5-0.6 BtCO_(2).The share of hydrogen in the final energy of the steel and chemical sectors is estimated to be 9%-19%and 17%-25%,collectively accounting for 36%-42%of total hydrogen demand and 46%-50%of total emission reduction potential.Realizing hydrogen's emission reduction potential relies on the rapid development of hydrogen production,transportation,and utilization technologies.Firstly,the development of on-site electrolysis for hydrogen production and early deployment of industrial hydrogen applications should be prioritized to stimulate overall growth of hydrogen industry and cost reduction.Secondly,vigorous development of renewable energy electrolysis and hydrogen end-use technologies like fuel cells should be pursued,along with the demonstration and promotion of hydrogen transportation technologies.Lastly,further advancement of carbon market mechanisms is essential to support the widespread adoption of hydrogen technologies.
文摘Objective To isolate and identify bioactive constituents from the stem barks of I//icium difengpi. Methods The chemical constituents were isolated and purified by repeated silica gel, Sephadex LH-20, recrystallization, and preparative HPLC techniques. The structures of the compounds were identified on the basis of spectral data including NMR, MS, and IR. Results Two sesquiterpene lactones, majucin （I） and anisatin （2）, two steroids, l^-sitosterol （3） and daucosterol （4）, three carboxylic acids, 2-ethyldecanoic acid （5）, shikimic acid （6）, and 3,4-dihydrobenzoic acid （7）, and a flavonoid, quercetin （8）, were successively isolated from the stem barks of L difengpL Conclusion Apart from compound 3, other seven compounds are reported in this plant for the first time. The results suggested that the current studies on L difengpi is still far from being well known and therefore more studies need to be done for better understanding of this plant.
