Cropland (CP),native grassland (NG) and two shrub land treatments which were converted from cropland in 1985:seabuckthorn (Hippophae rhamnoides L.) (ST),and branchytamarisk (Tamarix ramosissima) (BT) were investigated...Cropland (CP),native grassland (NG) and two shrub land treatments which were converted from cropland in 1985:seabuckthorn (Hippophae rhamnoides L.) (ST),and branchytamarisk (Tamarix ramosissima) (BT) were investigated to evaluate effects of land use conversion on soil organic carbon (SOC) and soil nutrients in the semi-arid region of the Loess Plateau of China.Total organic carbon (TOC),light fraction organic carbon (LFOC),heavy fraction organic carbon (HFOC),total N (TN),nitrate nitrogen (NO 3-N) and nitrite nitrogen (NO 2-N),ammonium nitrogen (NH + 4-N),total P,and available P (AP) were measured.The results showed that SOC in NG,ST and BT were 12.7%,27.7% and 34.8% higher than that of the cropland,respectively.LFOC,light fraction (LF) dry matter,ratio of TOC to TN (C/N) and the ratio of TOC to AP (C/P) were higher in the shrub land or native grassland than in the cropland.Cropland had the highest TN,the sum of NO 3-N and NO 2-N,TP and AP due to the use of chemical fertilizers.TOC significantly correlated with LFOC,HFOC and C/N.LFOC significantly correlated with dry matter of the LF and C/N.TN,the sum of NO 3-N and NO 2-N and AP were significantly negatively correlated with TOC and LFOC.Therefore,land use conversion from cropland to shrub land,or maybe grassland,contributed to SOC sequestration and improved soil nutrients stabilization.展开更多
BACKGROUND:Budd-Chiari syndrome (B-CS) refers to post-hepatic portal hypertension and/or inferior vena cava hypertension caused by obstruction of blood flow at the portal cardinal hepatic vein.The treatments of B-CS i...BACKGROUND:Budd-Chiari syndrome (B-CS) refers to post-hepatic portal hypertension and/or inferior vena cava hypertension caused by obstruction of blood flow at the portal cardinal hepatic vein.The treatments of B-CS include operations on pathological membrane lesions,shunting and combined operations.Studies have shown that China,Japan,India and South Africa have a high incidence of B-CS.In China,the Yellow River Basin in Henan,Shandong,Jiangsu and Anhui Provinces also have a high incidence,around 10 per 100 000.METHODS:The clinical data of 221 B-CS patients were analyzed retrospectively.We focused on pathological types,surgical methods,effectiveness and complications of treatment,and follow-up.RESULTS:Based on imaging findings such as color ultrasonography,angiography or magnetic resonance angiography,the 221 patients were divided into 3 types (five subtypes):type Ia (72 patients),type Ib (20),type II (72),type IIIa (33),and type IIIb (24).Surgical procedures included balloon membranotomy with or without stent (65 patients),improved splenopneumopexy (18),radical resection of membrane and thrombus (17),inferior vena cava bypass [29,with cavocaval transflow (13) and cavoatrial transflow (16)],mesocaval shunt (41),splenocaval shunt (25),splenoatrial shunt (12),splenojugular shunt (6),and combined methods (8).The complication rate was 9.05% (20/221) and the perioperative death rate was 2.26% (5/221).All of the patients were followed up from 6 months to 5 years.The success rate was 84.6% (187/221),and the recurrence rate was 8.9% (9/101) and 13.5% (13/96) after 1-and 5-year follow-up,respectively.CONCLUSION:The rational choice of surgical treatment based on B-CS pathological typing may increase the success rate and decrease the recurrence.展开更多
Dynamic microwave-assisted extraction（DMAE） of flavonoids from Radix Scutellarie was described in this article. A TM010 microwave resonant cavity was used as the energy coupler. Several parameters of DMAE, including...Dynamic microwave-assisted extraction（DMAE） of flavonoids from Radix Scutellarie was described in this article. A TM010 microwave resonant cavity was used as the energy coupler. Several parameters of DMAE, including concentration, flow rate, volume of the extraction solvent, and irradiation power, were optimized. The extraction was performed under the optimum conditions for the extraction of total flavonoids. The total flavonoids were determined by UV-Vis spectrophotometry. The main bioactive components, including baicalin, baicalein, and wogonin, were determined by HPLC. The extraction yields of the tlavonoids obtained by DMAE were compared with those obtained by pressurized microwave assisted extraction （ PMAE）, ultrasonic extraction （ UE ）, soxhlet extraction （ SE ）, and reflux extraction（ RE）, and these results indicate that DMAE is a good alternative method for the extraction of flavonoids from Radix Scutellade.展开更多
As an important pilot target for shale gas exploration and development in China,the Longmaxi Formation shale in the Dianqianbei Area is characterized by high content of nitrogen,which severely increases exploration ri...As an important pilot target for shale gas exploration and development in China,the Longmaxi Formation shale in the Dianqianbei Area is characterized by high content of nitrogen,which severely increases exploration risk.Accordingly,this study explores the genesis of shale gas reservoir and the mechanism of nitrogen enrichment through investigating shale gas compositions,isotope features,and geochemical characteristics of associated gases.The high-nitrogen shale gas reservoir in the Longmaxi Formation is demonstrated to be a typical dry gas reservoir.Specifically,the alkane carbon isotope reversal is ascribed to the secondary cracking of crude oil and the Rayleigh fractionation induced by the basalt mantle plume.Such a thermogenic oil-type gas reservoir is composed of both oil-cracking gas and kerogen-cracking gas.The normally high nitrogen content(18.05%-40.92%) is attributed to organic matter cracking and thermal ammoniation in the high-maturity stage.Specifically,the high heat flow effect of the Emeishan mantle plume exacerbates the thermal cracking of organic matter in the Longmaxi Formation shale,accompanied by nitrogen generation.In comparison,the abnormally high nitrogen content(86.79%-98.54%) is ascribed to the communication between the atmosphere and deep underground fluids by deep faults,which results in hydrocarbon loss and nitrogen intrusion,acting as the key factor for deconstruction of the primary shale gas reservoir.Results of this study not only enrich research on genetic mechanism of high-maturity N_@ shale gas reservoirs,but also provide theoretical guidance for subsequent gas reservoir resource evaluation and well-drilling deployment in this area.展开更多
基金Project supported by the National Basic Research Program (973 Program) of China (No. 2007CB106804)the International S&T Cooperation Program (ISTCP) of China (No. 2006DFA31070)the International Foundation for Sciences(No. C/3313-2)
文摘Cropland (CP),native grassland (NG) and two shrub land treatments which were converted from cropland in 1985:seabuckthorn (Hippophae rhamnoides L.) (ST),and branchytamarisk (Tamarix ramosissima) (BT) were investigated to evaluate effects of land use conversion on soil organic carbon (SOC) and soil nutrients in the semi-arid region of the Loess Plateau of China.Total organic carbon (TOC),light fraction organic carbon (LFOC),heavy fraction organic carbon (HFOC),total N (TN),nitrate nitrogen (NO 3-N) and nitrite nitrogen (NO 2-N),ammonium nitrogen (NH + 4-N),total P,and available P (AP) were measured.The results showed that SOC in NG,ST and BT were 12.7%,27.7% and 34.8% higher than that of the cropland,respectively.LFOC,light fraction (LF) dry matter,ratio of TOC to TN (C/N) and the ratio of TOC to AP (C/P) were higher in the shrub land or native grassland than in the cropland.Cropland had the highest TN,the sum of NO 3-N and NO 2-N,TP and AP due to the use of chemical fertilizers.TOC significantly correlated with LFOC,HFOC and C/N.LFOC significantly correlated with dry matter of the LF and C/N.TN,the sum of NO 3-N and NO 2-N and AP were significantly negatively correlated with TOC and LFOC.Therefore,land use conversion from cropland to shrub land,or maybe grassland,contributed to SOC sequestration and improved soil nutrients stabilization.
文摘BACKGROUND:Budd-Chiari syndrome (B-CS) refers to post-hepatic portal hypertension and/or inferior vena cava hypertension caused by obstruction of blood flow at the portal cardinal hepatic vein.The treatments of B-CS include operations on pathological membrane lesions,shunting and combined operations.Studies have shown that China,Japan,India and South Africa have a high incidence of B-CS.In China,the Yellow River Basin in Henan,Shandong,Jiangsu and Anhui Provinces also have a high incidence,around 10 per 100 000.METHODS:The clinical data of 221 B-CS patients were analyzed retrospectively.We focused on pathological types,surgical methods,effectiveness and complications of treatment,and follow-up.RESULTS:Based on imaging findings such as color ultrasonography,angiography or magnetic resonance angiography,the 221 patients were divided into 3 types (five subtypes):type Ia (72 patients),type Ib (20),type II (72),type IIIa (33),and type IIIb (24).Surgical procedures included balloon membranotomy with or without stent (65 patients),improved splenopneumopexy (18),radical resection of membrane and thrombus (17),inferior vena cava bypass [29,with cavocaval transflow (13) and cavoatrial transflow (16)],mesocaval shunt (41),splenocaval shunt (25),splenoatrial shunt (12),splenojugular shunt (6),and combined methods (8).The complication rate was 9.05% (20/221) and the perioperative death rate was 2.26% (5/221).All of the patients were followed up from 6 months to 5 years.The success rate was 84.6% (187/221),and the recurrence rate was 8.9% (9/101) and 13.5% (13/96) after 1-and 5-year follow-up,respectively.CONCLUSION:The rational choice of surgical treatment based on B-CS pathological typing may increase the success rate and decrease the recurrence.
基金the Development Program of the Science and Technology Department of Jilin Province(No20050560)
文摘Dynamic microwave-assisted extraction（DMAE） of flavonoids from Radix Scutellarie was described in this article. A TM010 microwave resonant cavity was used as the energy coupler. Several parameters of DMAE, including concentration, flow rate, volume of the extraction solvent, and irradiation power, were optimized. The extraction was performed under the optimum conditions for the extraction of total flavonoids. The total flavonoids were determined by UV-Vis spectrophotometry. The main bioactive components, including baicalin, baicalein, and wogonin, were determined by HPLC. The extraction yields of the tlavonoids obtained by DMAE were compared with those obtained by pressurized microwave assisted extraction （ PMAE）, ultrasonic extraction （ UE ）, soxhlet extraction （ SE ）, and reflux extraction（ RE）, and these results indicate that DMAE is a good alternative method for the extraction of flavonoids from Radix Scutellade.
基金financially supported by the National Science and Technology Major Project (2017ZX05063002–009)National Natural Science Foundation of China (41772150)+1 种基金Sichuan Province’s Key Project of Research and Development (18ZDYF0884)Qian Ke He Platform Talents [2017]5789-16。
文摘As an important pilot target for shale gas exploration and development in China,the Longmaxi Formation shale in the Dianqianbei Area is characterized by high content of nitrogen,which severely increases exploration risk.Accordingly,this study explores the genesis of shale gas reservoir and the mechanism of nitrogen enrichment through investigating shale gas compositions,isotope features,and geochemical characteristics of associated gases.The high-nitrogen shale gas reservoir in the Longmaxi Formation is demonstrated to be a typical dry gas reservoir.Specifically,the alkane carbon isotope reversal is ascribed to the secondary cracking of crude oil and the Rayleigh fractionation induced by the basalt mantle plume.Such a thermogenic oil-type gas reservoir is composed of both oil-cracking gas and kerogen-cracking gas.The normally high nitrogen content(18.05%-40.92%) is attributed to organic matter cracking and thermal ammoniation in the high-maturity stage.Specifically,the high heat flow effect of the Emeishan mantle plume exacerbates the thermal cracking of organic matter in the Longmaxi Formation shale,accompanied by nitrogen generation.In comparison,the abnormally high nitrogen content(86.79%-98.54%) is ascribed to the communication between the atmosphere and deep underground fluids by deep faults,which results in hydrocarbon loss and nitrogen intrusion,acting as the key factor for deconstruction of the primary shale gas reservoir.Results of this study not only enrich research on genetic mechanism of high-maturity N_@ shale gas reservoirs,but also provide theoretical guidance for subsequent gas reservoir resource evaluation and well-drilling deployment in this area.
