Objective: To investigate the relationship between the transcription of ANRIL, P15, P14 and P16 at the same locus and the regulation mechanism of ANRIL.Methods: Publicly available database of Cancer Cell Line Encyclop...Objective: To investigate the relationship between the transcription of ANRIL, P15, P14 and P16 at the same locus and the regulation mechanism of ANRIL.Methods: Publicly available database of Cancer Cell Line Encyclopedia(CCLE) was used in bioinformatic analyses. Methylation of Cp G islands was detected by denaturing high performance liquid chromatography(DHPLC). Gene transcript levels were determined using quantitative real-time polymerase chain reaction(q RTPCR) assays. An engineered P16-specific transcription factor and DNA methyltransferase were used to induce P16-specific DNA demethylation and methylation.Results: The expression level of ANRIL was positively and significantly correlated with that of P16 but not with that of P15 in the CCLE database. This was confirmed in human cell lines and patient colon tissue samples. In addition, ANRIL was significantly upregulated in colon cancer tissues. Transcription of ANRIL and P16 was observed only in cell lines in which the P16 alleles were unmethylated and not in cell lines with fully methylated P16 alleles.Notably, P16-specific methylation significantly decreased transcription of P16 and ANRIL in BGC823 and GES1 cells. In contrast, P16-specific demethylation re-activated transcription of ANRIL and P16 in H1299 cells(P<0.001).Alteration of ANRIL expression was not induced by P16 expression changes.Conclusions: ANRIL and P16 are coordinately transcribed in human cells and regulated by the methylation status of the P16 Cp G islands around the transcription start site.展开更多
Deep-level defects in silicon carbide(SiC)are critical to the control of the performance of SiC electron devices.In this paper,deep-level defects in aluminumion-implanted 4H-SiC after high-temperature annealingwere st...Deep-level defects in silicon carbide(SiC)are critical to the control of the performance of SiC electron devices.In this paper,deep-level defects in aluminumion-implanted 4H-SiC after high-temperature annealingwere studied using electron paramagnetic resonance(EPR)spectroscopy at temperatures of 77 K and 123 K under different illumination conditions.Results showed that the main defect in aluminum ion-implanted 4H-SiC was the positively charged carbon vacancy(VC+),and the higher the doping concentration was,the higher was the concentration of VC+.Itwas found that the type of material defectwas independent of the doping concentration,although more VC+defects were detected during photoexcitation and at lower temperatures.These results should be helpful in the fundamental research of p-type 4H-SiC fabrication in accordance with functional device development.展开更多
Integrated use of statistical process control (SPC) and engineering process control (EPC) has better performance than that by solely using SPC or EPC. But integrated scheme has resulted in the problem of “Window of O...Integrated use of statistical process control (SPC) and engineering process control (EPC) has better performance than that by solely using SPC or EPC. But integrated scheme has resulted in the problem of “Window of Opportunity” and autocorrelation. In this paper, advanced T2 statistics model and neural networks scheme are combined to solve the above problems: use T2 statistics technique to solve the problem of autocorrelation;adopt neural networks technique to solve the problem of “Window of Opportunity” and identification of disturbance causes. At the same time, regarding the shortcoming of neural network technique that its algorithm has a low speed of convergence and it is usually plunged into local optimum easily. Genetic algorithm was proposed to train samples in this paper. Results of the simulation ex-periments show that this method can detect the process disturbance quickly and accurately as well as identify the dis-turbance type.展开更多
An adequate and uniform press wheel pressure is crucial for the homogeneous development of a crop,as it affects actual seeding depth and germination rate.The problems of uneven compaction of seed furrow and consistenc...An adequate and uniform press wheel pressure is crucial for the homogeneous development of a crop,as it affects actual seeding depth and germination rate.The problems of uneven compaction of seed furrow and consistency of seeding depth can be caused by the pressure fluctuation of the coil-spring pressure control device(CPCD)when the no-till planter is working on the unplowed ground.In this study,a pneumatic pressure control device(PPCD)was designed for the no-till planter,the key structural parameters of air spring for press wheel pressure(PWP)stability were determined by theoretical analysis and parameter calculation.Using the gas-structure coupling finite element simulation method(FESM),the piston radius,piston angle,and cord angle of the air spring are selected as the test factors,and the vertical stiffness was used as the test index to carry out the quadratic rotation orthogonal combination test to establish the regression model of test index and factor.The bench test of the PPCD was carried out under the optimal parameter combination,piston radius of 27.2 mm,piston angle of 11.7°,and cord angle of 30.0°.The vertical stiffness verification test showed that the simulation test was consistent with the bench test result,the vertical stiffness simulation error was 7.1%,and the internal air pressure simulation error was 3.0%;The control response test showed that the average response time of the air spring inflating and deflating was 0.80 s,the maximum overshoot was 4.33%during inflation,and no pressure overshoot during deflation;Under the condition of-40-40 mm surface relief height,the PPCD could effectively reduce the pressure fluctuation compared with the CPCD,and the average reduction of the pressure fluctuation was about 25.1%.展开更多
The deployment of mega constellations has had a significant effect on the compounding space debris environment,increasing the number of on-orbit objects in all conditions and damaging the stability of the space debris...The deployment of mega constellations has had a significant effect on the compounding space debris environment,increasing the number of on-orbit objects in all conditions and damaging the stability of the space debris environment.The increased density of space objects is associated with an increased risk of on-orbit collisions.Collision risk exists not only between a mega constellation and the space debris environment but also inside a mega constellation.In this study,we used the Starlink constellation to investigate the self-induced collision risk caused by malfunctioning satellites.First,we analyzed the conjunction condition between malfunctioning and operative satellites based on long-term orbital evolution characteristics.The collision probability was then calculated based on the conjunction analysis results.The results show that malfunctioning satellites in Phase 1 cause an 86.2%self-induced collision probability based on a malfunctioning rate of 1%,which is close to the collision probability caused by objects larger than 6 cm during five years of service.Therefore,self-induced collisions are another important risk factor for the Starlink constellation.展开更多
The natural environment provides material essentials for human survival and development. The characteristics,processes, regional differentiation and forcing mechanisms of the elements of the natural environment(e.g. g...The natural environment provides material essentials for human survival and development. The characteristics,processes, regional differentiation and forcing mechanisms of the elements of the natural environment(e.g. geomorphology,climate, hydrology, soil, etc.) are the main objects of research in physical geography. China has a complex natural environment and huge regional differentiation and therefore it provides outstanding reserach opportunities in physical geography. This review summarizes the most important developments and the main contributions of research in the physical geography and human living environment in China during the past 70 years. The major topics addressed are the uplift of the Tibetan Plateau and the evolution of its cryosphere, the development of fluvial systems, the acidification of the vast arid region of the Asian interior, variations in the monsoon and westerly climate systems on multiple timescales, the development of lakes and wetlands, the watershed system model, soil erosion, past human-environment interactions, biogeography, and physical geographic zonality. After briefly introducing international research developments, we review the history of research in physical geography in China, focusing on the major achievements and major academic debates, and finally we summarize the status of current research and the future prospects. We propose that in the context of the national demand for the construction of an ecological civilization, we should make full use of the research findings of physical geography, and determine the patterns and mechanisms of natural environmental processes in order to continue to promote the continued contribution of physical geography to national development strategies, and to further contribute to the theory of physical geography from a global perspective.展开更多
Although various coaly source rocks widely developed in the Carboniferous-Permian(C-P)of the Bohai Bay Basin,their geochemical characteristics and hydrocarbon generation potential are poorly understood.This study aims...Although various coaly source rocks widely developed in the Carboniferous-Permian(C-P)of the Bohai Bay Basin,their geochemical characteristics and hydrocarbon generation potential are poorly understood.This study aims to discriminate the contribution of hydrocarbon generation from different C-P coaly source rocks and clarify the differences within generated oils using organic geochemistry,organic petrology,and thermal simulation experiments.The coaly source rocks containt coal clarain and durain,carbonaceous shale,and shale deposited in deltaic and lagoonal environment.The results indicated that clarain,durain,and carbonaceous shale exhibited higher hydrogen index and liquid-gas hydrocarbon yields than lagoonal and deltaic shales,which was mainly associated with the concentrations of sporinite,cutinite,and hydrogen-rich collodetrinite.Aliphatic hydro-carbons originated firom coal and carbonaceous shale presented lower Ts/(Ts+Tm),Ga/17α(H)21β(H)-C_(30)hopane,18α(H)-oleanane/17α(H)21β(H)-C_(30)hopane ratios,and higher 17β3(H)21α(H)-C_(30)Morane/17α(H)21β(H)-C_(30)hopane than deltaic lagoonal shales.Parameters of aromatic hydrocarbons generated from five lithologies of coaly source rocks trended as clear group distribution,e.g.,clarain and durain showing lower MNR,DBT/Fluorene(F)ratios and higher DBF/F ratio than coaly shales.The distinct descending trend of hydrocarbon potential is obtained from clarain,durain,carbonaceous shale to lagoonal and deltaic shales,implying dominated the petroleum and natural gas supplement from coal and carbonaceous shale.The difference between aliphatic and aromatic hydrocarbons provides a significant contribution to analyze the generic relationship between coaly source rock and lacustrine shale.Our results illustrate the importance of coaly source rocks for the in-depth oil-gas exploration of the Bohai Bay Basin and understanding hydrocarbon generation potential of source rocks in coal bearing strata.展开更多
Soil arsenic(As)pollution from mining and industrial sources is a serious issue in China.Earthworms are considered ecosystem engineers and contribute to soil fertility development and maintenance of soil physico-chemi...Soil arsenic(As)pollution from mining and industrial sources is a serious issue in China.Earthworms are considered ecosystem engineers and contribute to soil fertility development and maintenance of soil physico-chemical properties.In this study,earthworms were exposed to soils with different sodium arsenite concentrations(0,5,20,and 80 mg As kg^(-1))for 60 d to investigate the changes in soil properties and the responses of the earthworms(e.g.,burrowing activity and respiration).Earthworm burrowing activity decreased with increasing arsenite concentrations,and earthworm respiration was significantly lower in soils with 20 and 80 mg As kg^(-1) compared to 0 mg As kg^(-1).Changes in soil properties were also observed after incubation of As-amended soil with earthworms.Specifically,soil pH decreased,while soil electrical conductivity and contents of soil NH3--N,Olsen-P,and available K increased.Our results suggest that arsenite negatively impacts the metabolic activity of earthworms,leading to reduced burrowing activity,which in turn modifies the effects of earthworms on soil fertility and remediation.展开更多
基金supported by the National Natural Science Foundation of China (No. 91640108)the 973 Program of China (No. 2015CB553902)
文摘Objective: To investigate the relationship between the transcription of ANRIL, P15, P14 and P16 at the same locus and the regulation mechanism of ANRIL.Methods: Publicly available database of Cancer Cell Line Encyclopedia(CCLE) was used in bioinformatic analyses. Methylation of Cp G islands was detected by denaturing high performance liquid chromatography(DHPLC). Gene transcript levels were determined using quantitative real-time polymerase chain reaction(q RTPCR) assays. An engineered P16-specific transcription factor and DNA methyltransferase were used to induce P16-specific DNA demethylation and methylation.Results: The expression level of ANRIL was positively and significantly correlated with that of P16 but not with that of P15 in the CCLE database. This was confirmed in human cell lines and patient colon tissue samples. In addition, ANRIL was significantly upregulated in colon cancer tissues. Transcription of ANRIL and P16 was observed only in cell lines in which the P16 alleles were unmethylated and not in cell lines with fully methylated P16 alleles.Notably, P16-specific methylation significantly decreased transcription of P16 and ANRIL in BGC823 and GES1 cells. In contrast, P16-specific demethylation re-activated transcription of ANRIL and P16 in H1299 cells(P<0.001).Alteration of ANRIL expression was not induced by P16 expression changes.Conclusions: ANRIL and P16 are coordinately transcribed in human cells and regulated by the methylation status of the P16 Cp G islands around the transcription start site.
基金supported by the National Natural Science Foundation of China (No. 51575389, 51761135106)the National Key Research and Development Program of China (2016YFB1102203)+2 种基金the State Key Laboratory of Precision Measurement Technology and Instruments (Pilt1705)the ‘111’ Project by the State Administration of Foreign Experts Affairsthe Ministry of Education of China (Grant No. B07014)
文摘Deep-level defects in silicon carbide(SiC)are critical to the control of the performance of SiC electron devices.In this paper,deep-level defects in aluminumion-implanted 4H-SiC after high-temperature annealingwere studied using electron paramagnetic resonance(EPR)spectroscopy at temperatures of 77 K and 123 K under different illumination conditions.Results showed that the main defect in aluminum ion-implanted 4H-SiC was the positively charged carbon vacancy(VC+),and the higher the doping concentration was,the higher was the concentration of VC+.Itwas found that the type of material defectwas independent of the doping concentration,although more VC+defects were detected during photoexcitation and at lower temperatures.These results should be helpful in the fundamental research of p-type 4H-SiC fabrication in accordance with functional device development.
文摘Integrated use of statistical process control (SPC) and engineering process control (EPC) has better performance than that by solely using SPC or EPC. But integrated scheme has resulted in the problem of “Window of Opportunity” and autocorrelation. In this paper, advanced T2 statistics model and neural networks scheme are combined to solve the above problems: use T2 statistics technique to solve the problem of autocorrelation;adopt neural networks technique to solve the problem of “Window of Opportunity” and identification of disturbance causes. At the same time, regarding the shortcoming of neural network technique that its algorithm has a low speed of convergence and it is usually plunged into local optimum easily. Genetic algorithm was proposed to train samples in this paper. Results of the simulation ex-periments show that this method can detect the process disturbance quickly and accurately as well as identify the dis-turbance type.
基金This work was supported by the National Natural Science Foundation of China(Grant No.52175260)Gratitude should be expressed to all the members of the Conservation Tillage Research Centre.
文摘An adequate and uniform press wheel pressure is crucial for the homogeneous development of a crop,as it affects actual seeding depth and germination rate.The problems of uneven compaction of seed furrow and consistency of seeding depth can be caused by the pressure fluctuation of the coil-spring pressure control device(CPCD)when the no-till planter is working on the unplowed ground.In this study,a pneumatic pressure control device(PPCD)was designed for the no-till planter,the key structural parameters of air spring for press wheel pressure(PWP)stability were determined by theoretical analysis and parameter calculation.Using the gas-structure coupling finite element simulation method(FESM),the piston radius,piston angle,and cord angle of the air spring are selected as the test factors,and the vertical stiffness was used as the test index to carry out the quadratic rotation orthogonal combination test to establish the regression model of test index and factor.The bench test of the PPCD was carried out under the optimal parameter combination,piston radius of 27.2 mm,piston angle of 11.7°,and cord angle of 30.0°.The vertical stiffness verification test showed that the simulation test was consistent with the bench test result,the vertical stiffness simulation error was 7.1%,and the internal air pressure simulation error was 3.0%;The control response test showed that the average response time of the air spring inflating and deflating was 0.80 s,the maximum overshoot was 4.33%during inflation,and no pressure overshoot during deflation;Under the condition of-40-40 mm surface relief height,the PPCD could effectively reduce the pressure fluctuation compared with the CPCD,and the average reduction of the pressure fluctuation was about 25.1%.
文摘The deployment of mega constellations has had a significant effect on the compounding space debris environment,increasing the number of on-orbit objects in all conditions and damaging the stability of the space debris environment.The increased density of space objects is associated with an increased risk of on-orbit collisions.Collision risk exists not only between a mega constellation and the space debris environment but also inside a mega constellation.In this study,we used the Starlink constellation to investigate the self-induced collision risk caused by malfunctioning satellites.First,we analyzed the conjunction condition between malfunctioning and operative satellites based on long-term orbital evolution characteristics.The collision probability was then calculated based on the conjunction analysis results.The results show that malfunctioning satellites in Phase 1 cause an 86.2%self-induced collision probability based on a malfunctioning rate of 1%,which is close to the collision probability caused by objects larger than 6 cm during five years of service.Therefore,self-induced collisions are another important risk factor for the Starlink constellation.
基金supported by the National Natural Science Foundation of China (Grant No. 41842050)
文摘The natural environment provides material essentials for human survival and development. The characteristics,processes, regional differentiation and forcing mechanisms of the elements of the natural environment(e.g. geomorphology,climate, hydrology, soil, etc.) are the main objects of research in physical geography. China has a complex natural environment and huge regional differentiation and therefore it provides outstanding reserach opportunities in physical geography. This review summarizes the most important developments and the main contributions of research in the physical geography and human living environment in China during the past 70 years. The major topics addressed are the uplift of the Tibetan Plateau and the evolution of its cryosphere, the development of fluvial systems, the acidification of the vast arid region of the Asian interior, variations in the monsoon and westerly climate systems on multiple timescales, the development of lakes and wetlands, the watershed system model, soil erosion, past human-environment interactions, biogeography, and physical geographic zonality. After briefly introducing international research developments, we review the history of research in physical geography in China, focusing on the major achievements and major academic debates, and finally we summarize the status of current research and the future prospects. We propose that in the context of the national demand for the construction of an ecological civilization, we should make full use of the research findings of physical geography, and determine the patterns and mechanisms of natural environmental processes in order to continue to promote the continued contribution of physical geography to national development strategies, and to further contribute to the theory of physical geography from a global perspective.
基金supported by the Certificate of National Science and Technology Major Project of the Ministry of Science and Technology of China(No.2016ZX05006-007-004)National Natural Science Foundation of China(Grant Nos.41702139,420772164,42072130,and U1762217)+2 种基金Natural Science Foundation of Shandong Province(No.ZR2017BD036)the Fundamental Research Funds for the Central Universities(No.18CX02008A)Taishan Scholar Program of Shandong Province(No.TSQN201812030).
文摘Although various coaly source rocks widely developed in the Carboniferous-Permian(C-P)of the Bohai Bay Basin,their geochemical characteristics and hydrocarbon generation potential are poorly understood.This study aims to discriminate the contribution of hydrocarbon generation from different C-P coaly source rocks and clarify the differences within generated oils using organic geochemistry,organic petrology,and thermal simulation experiments.The coaly source rocks containt coal clarain and durain,carbonaceous shale,and shale deposited in deltaic and lagoonal environment.The results indicated that clarain,durain,and carbonaceous shale exhibited higher hydrogen index and liquid-gas hydrocarbon yields than lagoonal and deltaic shales,which was mainly associated with the concentrations of sporinite,cutinite,and hydrogen-rich collodetrinite.Aliphatic hydro-carbons originated firom coal and carbonaceous shale presented lower Ts/(Ts+Tm),Ga/17α(H)21β(H)-C_(30)hopane,18α(H)-oleanane/17α(H)21β(H)-C_(30)hopane ratios,and higher 17β3(H)21α(H)-C_(30)Morane/17α(H)21β(H)-C_(30)hopane than deltaic lagoonal shales.Parameters of aromatic hydrocarbons generated from five lithologies of coaly source rocks trended as clear group distribution,e.g.,clarain and durain showing lower MNR,DBT/Fluorene(F)ratios and higher DBF/F ratio than coaly shales.The distinct descending trend of hydrocarbon potential is obtained from clarain,durain,carbonaceous shale to lagoonal and deltaic shales,implying dominated the petroleum and natural gas supplement from coal and carbonaceous shale.The difference between aliphatic and aromatic hydrocarbons provides a significant contribution to analyze the generic relationship between coaly source rock and lacustrine shale.Our results illustrate the importance of coaly source rocks for the in-depth oil-gas exploration of the Bohai Bay Basin and understanding hydrocarbon generation potential of source rocks in coal bearing strata.
基金This study was financed by the National Key R&D Program of China(No.2017Y FD 0501405)the National Natural Science Foundation of China(No.41471203)+1 种基金the Natural Science Projects of Henan University of Technology,China(No.2019BS037)the Key Projects of Shanghai Municipal Agricultural Commission,China(No.20166-3-2).
文摘Soil arsenic(As)pollution from mining and industrial sources is a serious issue in China.Earthworms are considered ecosystem engineers and contribute to soil fertility development and maintenance of soil physico-chemical properties.In this study,earthworms were exposed to soils with different sodium arsenite concentrations(0,5,20,and 80 mg As kg^(-1))for 60 d to investigate the changes in soil properties and the responses of the earthworms(e.g.,burrowing activity and respiration).Earthworm burrowing activity decreased with increasing arsenite concentrations,and earthworm respiration was significantly lower in soils with 20 and 80 mg As kg^(-1) compared to 0 mg As kg^(-1).Changes in soil properties were also observed after incubation of As-amended soil with earthworms.Specifically,soil pH decreased,while soil electrical conductivity and contents of soil NH3--N,Olsen-P,and available K increased.Our results suggest that arsenite negatively impacts the metabolic activity of earthworms,leading to reduced burrowing activity,which in turn modifies the effects of earthworms on soil fertility and remediation.
