Endogenous elicitor, termed cellulase-degraded cell wall (CDW), was prepared from the cell wall of suspension-cultured ginseng (Panax ginseng C.A. Meyer) cells via cellulase degradation. CDW activated the NADPH oxidas...Endogenous elicitor, termed cellulase-degraded cell wall (CDW), was prepared from the cell wall of suspension-cultured ginseng (Panax ginseng C.A. Meyer) cells via cellulase degradation. CDW activated the NADPH oxidase activity of isolated plasma membranes and stimulated in vivo H2O2 generation in ginseng cell suspensions. CDW also increased the activity of phenylalanine ammonia lyase (PAL), expression of a P. ginseng squalene epoxidase (sqe) gene and saponin synthesis. NADPH oxidase inhibitors inhibited both in vitro NADPH oxidase activity and in vivo H2O2 generation. Induction of PAL activity, saponin synthesis and sqe gene expression were all inhibited by such inhibitor treatments and reduced by incubation with catalase and HA scavengers. These data indicate that activation of NADPH oxidase and generation of H2O2 are essential signalling events mediating defence responses induced by the endogenous elicitor(s) present in CDW.展开更多
设计了一种电流增益和跨导均可线性调节的电调谐电流差分跨导放大器(ECDTA)。电路改变了电流单位增益传输的固有模式,采用工作于弱反型区的MOS管跨导线性环,得到了可电调谐的电流增益;跨导放大级采用CMOS对管和浮地电源交叉耦合放大器,...设计了一种电流增益和跨导均可线性调节的电调谐电流差分跨导放大器(ECDTA)。电路改变了电流单位增益传输的固有模式,采用工作于弱反型区的MOS管跨导线性环,得到了可电调谐的电流增益;跨导放大级采用CMOS对管和浮地电源交叉耦合放大器,在传输特性的非线性误差不大于1%时,电路的差动输入电压范围可达±2.8 V。采用SMIC 60 nm CMOS工艺进行设计,在±0.9 V电源电压下仿真表明,电流传输增益可在0.105~8.98范围内线性调节,跨导值可在0.056 m S^0.204 m S范围内线性调节;电路总功耗仅为0.31 m W。展开更多
The ratio of nitrogen/phosphorus （N/P） is known to affect cell proliferation of some marine micro algae. We evaluated the effect of N/P ratios on the proliferation and succession of phytoplankton using five marine m...The ratio of nitrogen/phosphorus （N/P） is known to affect cell proliferation of some marine micro algae. We evaluated the effect of N/P ratios on the proliferation and succession of phytoplankton using five marine micro algae species. We used two sources of nitrogen, NH4Cl （N1） and urea （N2）, and a single source of phosphorous, NaH2PO4（P）. The optimal N/P ratio that differed among the five species was affected by the source of nitrogen, being as follows （N1/P, N2/P in order）： Thalassiosira sp. （30/1, 20/1）, Heterosigma akashiwo （30/1, 30/1）, Chroornonas salina （20/1, 30/1）, Chaetoceros gracilis （40/1, 60/1）, and A lexandrium sp. （10/1, 30/1）. Thus, the source of nitrogen must be considered when analyzing the N/P ratio. Our results provide insight for predicting phytoplankton succession in coastal waters and may be used to forecast the potential risk of harmful algal blooms.展开更多
Most of the bauxite resources in China are kaolinite-diaspore bauxite of middle to low grade, with a fine dissemination, and are difficultly separated. Direct flotation de-silication has been shown to be an effec- tiv...Most of the bauxite resources in China are kaolinite-diaspore bauxite of middle to low grade, with a fine dissemination, and are difficultly separated. Direct flotation de-silication has been shown to be an effec- tive method for de-silication of diaspore. In this study the effect of different factors, including pulp tem- perature, density, pH value, depressant, and collector dosage, on direct flotation of diaspore were investigated by laboratory experiments. The optimum conditions were identified and the flotation perfor- mance was improved. The results show that under optimum conditions （a pulp temperature around 40℃, a pulp density from 30% to 33g, a pH value from 9.0 to 10.0, an air flow rate of 0.5 m3/（m2 rain）, a dispersant level from 35 to 70 g/t, and a collector level around 1000 g/t） an AI/Si ratio of 6.97 is obtained starting from an initial Al/Si ratio of about 4.71. The recovery of A1203 under these conditions was 86.94%.展开更多
North and west China has abundant coal resources, however, such resources make these regions prone to serious mine fire disasters. Although the copious sand and fly ash resources found in these areas can be used as fi...North and west China has abundant coal resources, however, such resources make these regions prone to serious mine fire disasters. Although the copious sand and fly ash resources found in these areas can be used as fire-fighting materials, conventional grouting is expensive because of water shortage and loess particles. A new compound material(i.e., a sand-suspended colloid), which comprises a mineral inorganic gel and an organic polymer, is developed in the current study to improve the quality of sand injection and reduce water wastage when grouting. The new material can steadily suspend the sand, through the addition of a small amount of colloid yielding steady sand-suspended slurry. The process of producing the slurry is convenient and quick, overcoming the shortage of sand-suspending thickeners which need heat and are difficult to produce. The space work model based on the theory of the double-electric layer is established to study the suspended mechanism of the solid particles in the sand-suspended colloid.The dispersion effect of the sand-suspended colloid is demonstrated by the incorporation of the electrostatic effect by the double-electric layer and the steric hindrance effect on the sand particles, ensuring the stability of the colloid system and the steady suspension of sand particles in the sand-suspended colloid.Mechanical analysis indicates that the sand is suspended steadily under the condition that the rock sand particles stress on the lower part of the fluid is less than the yield stress of the colloid. Finally, the fireprevention technology of sand suspension was applied and tested in the Daliuta Coal Mine, achieving successful results.展开更多
The goal of this project was to design, build, and test a pilot-scale floating modular treatment system for total phosphorus （TP） removal from nutrient-impaired lakes in central Florida, USA. The treatment sys-tem c...The goal of this project was to design, build, and test a pilot-scale floating modular treatment system for total phosphorus （TP） removal from nutrient-impaired lakes in central Florida, USA. The treatment sys-tem consisted of biological and physical-chemical treatment modules. First, investigations of prospective biological and physical-chemical treatment processes in mesocosms and in bench-scale experiments were conducted. Thirteen different mesocosms were constructed with a variety of substrates and combi-nations of macrophytes and tested for TP and orthophosphate （PO4-^3） removal efficiencies and potential areal removal rates. Bench-scale jar tests and column tests of seven types of absorptive media in addition to three commercial resins were conducted in order to test absorptive capacity. Once isolated process testing was complete, a floating island treatment system （FITS） was designed and deployed for eight months in a lake in central Florida. Phosphorus removal efficiencies of the mesocosm systems averaged about 40%-50%, providing an average uptake of 5.0 g.m ^2.a ^1 across all mesocosms. The best-performing mesocosms were a submerged aquatic vegetation （SAV） mesocosm and an algae scrubber （AGS）, which removed 20 and 50 mg.m ^2.d ^1, respectively, for an average removal of 5.5 and 12.0 g.m ^2.a ^1 for the SAV and AGS systems, Of the absorptive media, the best performance was alum residual （AR）, which reduced PO4-^3 concentrations by about 75% after 5 min of contact time. Of the commercial resins tested, the PhosX resin was superior to the others, removing about 40% of phosphorus after 30 rain and 60% after 60min. Under baseline operation conditions during deployment, the FITS exhibited mean PO4-^3 removal efficiencies of 53%; using the 50th and 90th percentile of PO4-^3 removal during deployment, and the footprint of the FITS system, yielded efficiencies for the combined FITS system of 56% and 86%, respectively, and areal phosphorus removal rates between 8.9 and 16.5 g.m ^2.a ^1展开更多
In recent years,due to the widespread application of flotation,a large number of plant remains related to the origin of rice agriculture have been found in the middle and lower reaches of the Yangtze River.Through the...In recent years,due to the widespread application of flotation,a large number of plant remains related to the origin of rice agriculture have been found in the middle and lower reaches of the Yangtze River.Through the study of these new findings,it has been discovered that the origin of rice agriculture was a long and gradual process lasting for thousands of years.This process can be divided into four stages:the stage of gestation took place around 10,000 years ago—human society was still in the hunting and gathering phase,but archaeological evidence of human-used or even cultivated Oryza plants from that time has been discovered;the early stage of transition took place around 9000–7000 years ago—archaeological evidence of rice farming from that time has been found,such as villages,domesticated rice,farming tools,etc.,but subsistence then was still mainly based on hunting and gathering,whereas rice farming and pig breeding,which fall into the agricultural production category,were only auxiliary production activities;the late stage of transition took place around 7000–5000 years ago,when the proportion of subsistence attained by hunting and gathering gradually declined while the proportion of rice farming increased day by day;and the stage of completion took place about 5000 years ago,when hunting and gathering was replaced by rice agriculture in the middle and lower reaches of the Yangtze River successively.展开更多
Retention efficiencies (RE) of scallop (Chlamys farreri),oyster (Crassostrea gigas) and mussel (Mytilus edulis) in a flow-through system were measured to understand the short-term response to various particle and orga...Retention efficiencies (RE) of scallop (Chlamys farreri),oyster (Crassostrea gigas) and mussel (Mytilus edulis) in a flow-through system were measured to understand the short-term response to various particle and organic matter concentrations.By comparing the RE of C.farreri with that of C.gigas and M.edulis,we gained further knowledge on the feeding physiological characteristics of C.farreri and ascertained the possible cause of high summer mortalities of this species.The experimental feeding conditions included natural differences in the abundance and composition of suspended seston,as well as conditions in which seston abundance and composition were manipulated by adding natural silt or cultured microalgae.The results show that in natural sea water,the minimum particle size for maximal retention in M.edulis,C.gigas and C.farreri was approximately 4,6,and 8 μm,respectively;the RE of 2-μm (equivalent spherical diameter) particles was 17%,19%,and 8%,respectively;and the relative standardized RE was 58%,49%,and 18%,respectively.In C.gigas and M.edulis,the minimal particle size for maximal retention did not change with food quality (organic content).C.farreri was more sensitive to fluctuations in particle concentration and organic content.With particle concentration increase,the minimal particle size for maximal retention in scallop shifted to large particles and the RE for 2-μm particle decreased from 8% in natural seawater to 1.6%-6% in silt-enriched groups.With organic content increase,the minimal particle size for maximal retention shifted from 8 to 5 μm in natural seawater.Variation in RE of C.farreri with food conditions and the relationship between lower RE and smaller particle size may hamper C.farreri from food taking due to the decrease in the size distribution of phytoplankton in Sungo Bay.展开更多
文摘Endogenous elicitor, termed cellulase-degraded cell wall (CDW), was prepared from the cell wall of suspension-cultured ginseng (Panax ginseng C.A. Meyer) cells via cellulase degradation. CDW activated the NADPH oxidase activity of isolated plasma membranes and stimulated in vivo H2O2 generation in ginseng cell suspensions. CDW also increased the activity of phenylalanine ammonia lyase (PAL), expression of a P. ginseng squalene epoxidase (sqe) gene and saponin synthesis. NADPH oxidase inhibitors inhibited both in vitro NADPH oxidase activity and in vivo H2O2 generation. Induction of PAL activity, saponin synthesis and sqe gene expression were all inhibited by such inhibitor treatments and reduced by incubation with catalase and HA scavengers. These data indicate that activation of NADPH oxidase and generation of H2O2 are essential signalling events mediating defence responses induced by the endogenous elicitor(s) present in CDW.
文摘设计了一种电流增益和跨导均可线性调节的电调谐电流差分跨导放大器(ECDTA)。电路改变了电流单位增益传输的固有模式,采用工作于弱反型区的MOS管跨导线性环,得到了可电调谐的电流增益;跨导放大级采用CMOS对管和浮地电源交叉耦合放大器,在传输特性的非线性误差不大于1%时,电路的差动输入电压范围可达±2.8 V。采用SMIC 60 nm CMOS工艺进行设计,在±0.9 V电源电压下仿真表明,电流传输增益可在0.105~8.98范围内线性调节,跨导值可在0.056 m S^0.204 m S范围内线性调节;电路总功耗仅为0.31 m W。
基金Supported by the Initial Fund for Introduced Talent from the Tianjin University of Science and Technology (No. 20090413) the National Key Technology R&D Program (No. 2010BAC68B04)
文摘The ratio of nitrogen/phosphorus （N/P） is known to affect cell proliferation of some marine micro algae. We evaluated the effect of N/P ratios on the proliferation and succession of phytoplankton using five marine micro algae species. We used two sources of nitrogen, NH4Cl （N1） and urea （N2）, and a single source of phosphorous, NaH2PO4（P）. The optimal N/P ratio that differed among the five species was affected by the source of nitrogen, being as follows （N1/P, N2/P in order）： Thalassiosira sp. （30/1, 20/1）, Heterosigma akashiwo （30/1, 30/1）, Chroornonas salina （20/1, 30/1）, Chaetoceros gracilis （40/1, 60/1）, and A lexandrium sp. （10/1, 30/1）. Thus, the source of nitrogen must be considered when analyzing the N/P ratio. Our results provide insight for predicting phytoplankton succession in coastal waters and may be used to forecast the potential risk of harmful algal blooms.
基金financial support from the National Key Technology R&D Program in the 11th Five Year Plan of China (No. 2008BAB31B02)the National Natural Science Foundation of China (No. 51174205)
文摘Most of the bauxite resources in China are kaolinite-diaspore bauxite of middle to low grade, with a fine dissemination, and are difficultly separated. Direct flotation de-silication has been shown to be an effec- tive method for de-silication of diaspore. In this study the effect of different factors, including pulp tem- perature, density, pH value, depressant, and collector dosage, on direct flotation of diaspore were investigated by laboratory experiments. The optimum conditions were identified and the flotation perfor- mance was improved. The results show that under optimum conditions （a pulp temperature around 40℃, a pulp density from 30% to 33g, a pH value from 9.0 to 10.0, an air flow rate of 0.5 m3/（m2 rain）, a dispersant level from 35 to 70 g/t, and a collector level around 1000 g/t） an AI/Si ratio of 6.97 is obtained starting from an initial Al/Si ratio of about 4.71. The recovery of A1203 under these conditions was 86.94%.
基金support of the research funds provided by the National Natural Science Foundation of China (Nos. 51304071, 51304073)the Open Projects of State Key Laboratory of Coal Resources and Safe Mining, China University of Mining & Technology of China (No. 12KF02)
文摘North and west China has abundant coal resources, however, such resources make these regions prone to serious mine fire disasters. Although the copious sand and fly ash resources found in these areas can be used as fire-fighting materials, conventional grouting is expensive because of water shortage and loess particles. A new compound material(i.e., a sand-suspended colloid), which comprises a mineral inorganic gel and an organic polymer, is developed in the current study to improve the quality of sand injection and reduce water wastage when grouting. The new material can steadily suspend the sand, through the addition of a small amount of colloid yielding steady sand-suspended slurry. The process of producing the slurry is convenient and quick, overcoming the shortage of sand-suspending thickeners which need heat and are difficult to produce. The space work model based on the theory of the double-electric layer is established to study the suspended mechanism of the solid particles in the sand-suspended colloid.The dispersion effect of the sand-suspended colloid is demonstrated by the incorporation of the electrostatic effect by the double-electric layer and the steric hindrance effect on the sand particles, ensuring the stability of the colloid system and the steady suspension of sand particles in the sand-suspended colloid.Mechanical analysis indicates that the sand is suspended steadily under the condition that the rock sand particles stress on the lower part of the fluid is less than the yield stress of the colloid. Finally, the fireprevention technology of sand suspension was applied and tested in the Daliuta Coal Mine, achieving successful results.
基金the Lake Jesup Total Phosphorus Removal Treatment Technologies Floating Island Pilot Project (25104) of St. Johns River Water Management District Palatka+1 种基金 FL USA
文摘The goal of this project was to design, build, and test a pilot-scale floating modular treatment system for total phosphorus （TP） removal from nutrient-impaired lakes in central Florida, USA. The treatment sys-tem consisted of biological and physical-chemical treatment modules. First, investigations of prospective biological and physical-chemical treatment processes in mesocosms and in bench-scale experiments were conducted. Thirteen different mesocosms were constructed with a variety of substrates and combi-nations of macrophytes and tested for TP and orthophosphate （PO4-^3） removal efficiencies and potential areal removal rates. Bench-scale jar tests and column tests of seven types of absorptive media in addition to three commercial resins were conducted in order to test absorptive capacity. Once isolated process testing was complete, a floating island treatment system （FITS） was designed and deployed for eight months in a lake in central Florida. Phosphorus removal efficiencies of the mesocosm systems averaged about 40%-50%, providing an average uptake of 5.0 g.m ^2.a ^1 across all mesocosms. The best-performing mesocosms were a submerged aquatic vegetation （SAV） mesocosm and an algae scrubber （AGS）, which removed 20 and 50 mg.m ^2.d ^1, respectively, for an average removal of 5.5 and 12.0 g.m ^2.a ^1 for the SAV and AGS systems, Of the absorptive media, the best performance was alum residual （AR）, which reduced PO4-^3 concentrations by about 75% after 5 min of contact time. Of the commercial resins tested, the PhosX resin was superior to the others, removing about 40% of phosphorus after 30 rain and 60% after 60min. Under baseline operation conditions during deployment, the FITS exhibited mean PO4-^3 removal efficiencies of 53%; using the 50th and 90th percentile of PO4-^3 removal during deployment, and the footprint of the FITS system, yielded efficiencies for the combined FITS system of 56% and 86%, respectively, and areal phosphorus removal rates between 8.9 and 16.5 g.m ^2.a ^1
文摘In recent years,due to the widespread application of flotation,a large number of plant remains related to the origin of rice agriculture have been found in the middle and lower reaches of the Yangtze River.Through the study of these new findings,it has been discovered that the origin of rice agriculture was a long and gradual process lasting for thousands of years.This process can be divided into four stages:the stage of gestation took place around 10,000 years ago—human society was still in the hunting and gathering phase,but archaeological evidence of human-used or even cultivated Oryza plants from that time has been discovered;the early stage of transition took place around 9000–7000 years ago—archaeological evidence of rice farming from that time has been found,such as villages,domesticated rice,farming tools,etc.,but subsistence then was still mainly based on hunting and gathering,whereas rice farming and pig breeding,which fall into the agricultural production category,were only auxiliary production activities;the late stage of transition took place around 7000–5000 years ago,when the proportion of subsistence attained by hunting and gathering gradually declined while the proportion of rice farming increased day by day;and the stage of completion took place about 5000 years ago,when hunting and gathering was replaced by rice agriculture in the middle and lower reaches of the Yangtze River successively.
基金Supported by the National Natural Science Foundation of China (No. 40676093)European Community INCO-DC Project ERBIC18CT980291+2 种基金National Basic Research Program of China (973 Program) (2006CB400608)National High Technology Research and Development Program of China (863 Program) (No. 2006AA100307)National High Technology Research and Development Program of China (863 Program)(No.2006BAD09A09)
文摘Retention efficiencies (RE) of scallop (Chlamys farreri),oyster (Crassostrea gigas) and mussel (Mytilus edulis) in a flow-through system were measured to understand the short-term response to various particle and organic matter concentrations.By comparing the RE of C.farreri with that of C.gigas and M.edulis,we gained further knowledge on the feeding physiological characteristics of C.farreri and ascertained the possible cause of high summer mortalities of this species.The experimental feeding conditions included natural differences in the abundance and composition of suspended seston,as well as conditions in which seston abundance and composition were manipulated by adding natural silt or cultured microalgae.The results show that in natural sea water,the minimum particle size for maximal retention in M.edulis,C.gigas and C.farreri was approximately 4,6,and 8 μm,respectively;the RE of 2-μm (equivalent spherical diameter) particles was 17%,19%,and 8%,respectively;and the relative standardized RE was 58%,49%,and 18%,respectively.In C.gigas and M.edulis,the minimal particle size for maximal retention did not change with food quality (organic content).C.farreri was more sensitive to fluctuations in particle concentration and organic content.With particle concentration increase,the minimal particle size for maximal retention in scallop shifted to large particles and the RE for 2-μm particle decreased from 8% in natural seawater to 1.6%-6% in silt-enriched groups.With organic content increase,the minimal particle size for maximal retention shifted from 8 to 5 μm in natural seawater.Variation in RE of C.farreri with food conditions and the relationship between lower RE and smaller particle size may hamper C.farreri from food taking due to the decrease in the size distribution of phytoplankton in Sungo Bay.
