MicroRNA(miR)-200b-3p has been associated with many tumors,but its involvement in pituitary adenoma is unclear.This study investigated the molecular mechanism underlying miR-200b-3p regulation in pituitary adenomas to...MicroRNA(miR)-200b-3p has been associated with many tumors,but its involvement in pituitary adenoma is unclear.This study investigated the molecular mechanism underlying miR-200b-3p regulation in pituitary adenomas to provide a theoretical basis for treatment.Bioinformatics was used to analyze pituitary adenoma-related genes and screen new targets related to RECK and miRNA.As well,the relationship between miR-200b-3p and RECK protein was verified using a double-luciferase reporter gene assay.The expression of miR-200b-3p in clinical samples was analyzed by in situ hybridization.Transfection of the miR-200b-3p inhibitor and small interfering-RECK(si-RECK)was verified by qPCR.GH3 cell viability and proliferation were detected using CCK8 and EdU assays.Apoptosis was detected by flow cytometry and western blotting.Wound healing and Transwell assays were used to detect cell migration and invasion.The effects of miR-200b-3p and RECK on GH3 cells were verified using salvage experiments.miR-200b-3p was highly expressed in pituitary tumor tissue.Inhibitors of miR-200b-3p inhibited cell proliferation promoted cell apoptosis,inhibited invasion and migration,and inhibited the expression of matrix metalloproteinases.Interestingly,miR-200b-3p negatively regulated RECK.The expression of RECK in pituitary adenoma tissues was lower than that in neighboring tissues.Si-RECK rescued the function of miR-200b-3p inhibitors in the above cellular behaviors,and miR-200b-3p accelerated the development of pituitary adenoma by negatively regulating RECK expression.In summary,this study investigated the molecular mechanism by which miR-200b-3p regulates the progression of pituitary adenoma through the negative regulation of RECK.The findings provide a new target for the treatment of pituitary adenoma.展开更多
Previous studies have shown that leak electro ns in cusped field thrusters can move along the channel axis to the anode after crossing the magnetic cusp on the exit.In this paper,a onedimensional fluid model is built ...Previous studies have shown that leak electro ns in cusped field thrusters can move along the channel axis to the anode after crossing the magnetic cusp on the exit.In this paper,a onedimensional fluid model is built along two typical electron paths to study the influence of leak electrons on the discharge characteristics of a cusped field thruster,considering the electron temperature equation.It is found that the frequencies of low-frequency oscillations increase with a decrease in the proportion of leak electrons,which is related to an increase in the ion speed in the channel.Simulation results show that the position of the peak electron temperature is near the magnetic cusp on the exit and the position of the peak electron density is located downstream from the middle magnetic tip.With a decrease in the proportion of the leak electrons,the peak electron temperature and peak electron density decrease and the position of the peak electron density moves away from the exit,which is related to a decrease in the potential fall on the exit and an increase in confinement of electrons to the middle magnetic cusp.展开更多
Litter decomposition and ecological stoichiometry of nutrient release is an important part of material cycling and energy flow in forest ecosystems.In a study of the ecological stoichiometry and nutrient release durin...Litter decomposition and ecological stoichiometry of nutrient release is an important part of material cycling and energy flow in forest ecosystems.In a study of the ecological stoichiometry and nutrient release during litter decomposition in a pine–oak forest ecosystem of the Grain to Green Program(GTGP)area of northern China,a typical pine and oak species(PDS:Pinus densiflora Sieb.,QAC:Quercus acutissima Carr.)were selected in the Taiyi Mountain study area.The ecological stoichiometry characteristics of carbon(C),nitrogen(N)and phosphorus(P)and litter decomposition dynamics were studied by field sampling and quantitative analyses.The results showed the following.(1)The decomposition dynamics of both litters was slow-fast-slow.The most important climatic factor affecting the litter decomposition rate from May to October was precipitation and temperature from November to April of the following year.(2)Throughout the 300-day study,in both litters,C of the two litters was released,N first accumulated and was then released,and P exhibited a release-accumulate-release pattern.(3)C:P was significantly higher than C:N and N:P(p<0.05);the C:N of PSD litter was higher than that of QAC(p<0.05),but the N:P of QAC litter was higher than that of PSD litter(p<0.05).The C:N of both litters was very high in the study area,indicating that the nutrient release ability during litter decomposition in the two typical pine–oak forest ecosystems was relatively weak;therefore,more attention should be paid to nitrogen-fixing species and mixed forests in the GTGP area of northern China.展开更多
Many high-precision space missions need thrusters to produce thrust with low noise to compensate for disturbances and ensure satellite platform stability. Microwave ion thruster is characterized with a wide thrust ran...Many high-precision space missions need thrusters to produce thrust with low noise to compensate for disturbances and ensure satellite platform stability. Microwave ion thruster is characterized with a wide thrust range and potential for these missions. A cost-effective and accurate mathematical model is crucial for mHz-frequency thrust noise analysis and feedback controller design. The Particle-In-Cell(PIC) and global models are two common simulation tools. The PIC model is characterized with high accuracy but huge computation cost, which is difficult to analyze long-time performance characteristics. Now, the global model is only used for the discharge chamber with low accuracy and cannot reflect ion extraction properties. In this paper, an integrative mathematical model is built for a 1-cm microwave ion thruster and can reflect ion beamlet divergence and impingement on the Accelerator Grid(AG). Simulation results show good agreement with experiments at 0.06 sccm. However, the model demonstrates worse consistency with experiments when the flux increases to 0.1 sccm, which may be because the influence of neutral gas on the Electron Cyclotron Resonance(ECR) is not considered in the model. A long-time(1000 s) simulation is conducted with this model under 35 μN. It takes 3 hrs, and the thrust noise reaches 1 μN/Hz^(0.5) at 1 mHz.展开更多
(Ba_(1-x)Sr_(x))(MnyTi1-y)O_(3)(BSMT)ceramics with x=35,40 mol%and y=0,0.1,0.2,0.3,0.4,0.5 mol%were prepared using a conventional solid-state reaction approach.The dielectric and ferroelectric properties were characte...(Ba_(1-x)Sr_(x))(MnyTi1-y)O_(3)(BSMT)ceramics with x=35,40 mol%and y=0,0.1,0.2,0.3,0.4,0.5 mol%were prepared using a conventional solid-state reaction approach.The dielectric and ferroelectric properties were characterized using impedance analysis and polarization-electric field(P-E)hysteresis loop measurements,respectively.The adiabatic temperature drop was directly measured using a thermocouple when the applied electric field was removed.The results indicate that high permittivity and low dielectric losses were obtained by doping 0.1-0.4 mol%of manganese ions in(BaSr)TiO_(3)(BST)specimens.A maximum electrocaloric effect(ECE)of 2.75 K in temperature change with electrocaloric strength of 0.55 K·(MV/m)^(-1)was directly obtained at~21℃and 50 kV/cm in Ba_(0.6)Sr_(0.4)Mn_(0.001)Ti_(0.999)O_(3) sample,offering a promising ECE material for practical refrigeration devices working at room temperature.展开更多
Solid-state cooling technology based on electrocaloric effect(ECE)has been advanced as an alternative to replace the vapour-compression approach to overcome the releasing of the global warming gases.However,the develo...Solid-state cooling technology based on electrocaloric effect(ECE)has been advanced as an alternative to replace the vapour-compression approach to overcome the releasing of the global warming gases.However,the development in high ECE materials is still a challenge.In this work,polarization merging strategy was proposed to achieve a large ECE in xBa(Sn_(0.07)Ti_(0.93))O_(3)–(1−x)Ba(Hf_(0.1)Ti_(0.9))O_(3) ferroelectric ceramics,where x=0,0.2,0.4,0.6,0.8,and 1.Ba(Sn_(0.07)Ti_(0.93))O_(3) with an orthorhombic phase and Ba(Hf_(0.1)Ti_(0.9))O_(3) with a rhombohedral phase at room temperature were prepared beforehand as precursors,and phase-coexisted xBSnT–(1−x)BHfT ceramics were formed via a solid-state reaction approach.Phase coexisting structures were confirmed using the X-ray diffraction.The merged polarization was confirmed by the dielectric and ferroelectric properties.Optimal ECEs were obtained for 0.2BSnT–0.8BHfT ceramics,i.e.,adiabatic temperature change DT=2.16±0.08 K at 80℃and 5 MV/m,and DT=3.35±0.09 K at 80℃and 7 MV/m.展开更多
The electrocaloric effect(ECE),known for its environmentally friendly characteristics,holds significant promise for advancing next-generation solid-state refrigeration technologies.Achieving a large ECE along with a w...The electrocaloric effect(ECE),known for its environmentally friendly characteristics,holds significant promise for advancing next-generation solid-state refrigeration technologies.Achieving a large ECE along with a wide working temperature range near room temperature remains a key developmental goal.In this study,we successfully obtained a substantial ECE of 1.78 K and an extensive working temperature range of 103 K(AT>1.52 K)near room temperature in CaZrO_(3)-modified BaTiO_(3) lead-free ferroelectric ceramics.Furthermore,this achievement was verified using direct methods.The piezoresponse force microscopy(PFM)results suggest that the broad temperature range is attributed to the formation of ferroelectric microdomains and polar nanoregions(PNRs).Furthermore,X-ray photoelectron spectroscopy(XPS)and ultraviolet-visible(UV-Vis)spectroscopy reveal a decrease in the oxygen vacancy concentration and an increase in the bandgap for higher CaZrO_(3) doping levels.These changes synergistically enhance the maximum applied electric field,helping to achieve a high-performance EcE near room temperature.This research presents a straightforward and effective approach for achieving high-performance ECEs in BaTiOg lead-free ceramics,offering promising prospects for application in next-generation solid-state refrigeration technologies.展开更多
基金supported by Correlation between RECK and GH-type pituitary adenomas(No.21JR11RE027).
文摘MicroRNA(miR)-200b-3p has been associated with many tumors,but its involvement in pituitary adenoma is unclear.This study investigated the molecular mechanism underlying miR-200b-3p regulation in pituitary adenomas to provide a theoretical basis for treatment.Bioinformatics was used to analyze pituitary adenoma-related genes and screen new targets related to RECK and miRNA.As well,the relationship between miR-200b-3p and RECK protein was verified using a double-luciferase reporter gene assay.The expression of miR-200b-3p in clinical samples was analyzed by in situ hybridization.Transfection of the miR-200b-3p inhibitor and small interfering-RECK(si-RECK)was verified by qPCR.GH3 cell viability and proliferation were detected using CCK8 and EdU assays.Apoptosis was detected by flow cytometry and western blotting.Wound healing and Transwell assays were used to detect cell migration and invasion.The effects of miR-200b-3p and RECK on GH3 cells were verified using salvage experiments.miR-200b-3p was highly expressed in pituitary tumor tissue.Inhibitors of miR-200b-3p inhibited cell proliferation promoted cell apoptosis,inhibited invasion and migration,and inhibited the expression of matrix metalloproteinases.Interestingly,miR-200b-3p negatively regulated RECK.The expression of RECK in pituitary adenoma tissues was lower than that in neighboring tissues.Si-RECK rescued the function of miR-200b-3p inhibitors in the above cellular behaviors,and miR-200b-3p accelerated the development of pituitary adenoma by negatively regulating RECK expression.In summary,this study investigated the molecular mechanism by which miR-200b-3p regulates the progression of pituitary adenoma through the negative regulation of RECK.The findings provide a new target for the treatment of pituitary adenoma.
文摘Previous studies have shown that leak electro ns in cusped field thrusters can move along the channel axis to the anode after crossing the magnetic cusp on the exit.In this paper,a onedimensional fluid model is built along two typical electron paths to study the influence of leak electrons on the discharge characteristics of a cusped field thruster,considering the electron temperature equation.It is found that the frequencies of low-frequency oscillations increase with a decrease in the proportion of leak electrons,which is related to an increase in the ion speed in the channel.Simulation results show that the position of the peak electron temperature is near the magnetic cusp on the exit and the position of the peak electron density is located downstream from the middle magnetic tip.With a decrease in the proportion of the leak electrons,the peak electron temperature and peak electron density decrease and the position of the peak electron density moves away from the exit,which is related to a decrease in the potential fall on the exit and an increase in confinement of electrons to the middle magnetic cusp.
基金The study was subsidized by Grants from the Natural Science Foundation of Shandong Province of China(No.ZR2016CM49)the Special Fund for Forestry Scientific Research in the Public Interest(No.201404303-08).This work was supported by CFERN and BEIJING TECHNO SOLUTIONS Award Funds for excellent academic achievements.
文摘Litter decomposition and ecological stoichiometry of nutrient release is an important part of material cycling and energy flow in forest ecosystems.In a study of the ecological stoichiometry and nutrient release during litter decomposition in a pine–oak forest ecosystem of the Grain to Green Program(GTGP)area of northern China,a typical pine and oak species(PDS:Pinus densiflora Sieb.,QAC:Quercus acutissima Carr.)were selected in the Taiyi Mountain study area.The ecological stoichiometry characteristics of carbon(C),nitrogen(N)and phosphorus(P)and litter decomposition dynamics were studied by field sampling and quantitative analyses.The results showed the following.(1)The decomposition dynamics of both litters was slow-fast-slow.The most important climatic factor affecting the litter decomposition rate from May to October was precipitation and temperature from November to April of the following year.(2)Throughout the 300-day study,in both litters,C of the two litters was released,N first accumulated and was then released,and P exhibited a release-accumulate-release pattern.(3)C:P was significantly higher than C:N and N:P(p<0.05);the C:N of PSD litter was higher than that of QAC(p<0.05),but the N:P of QAC litter was higher than that of PSD litter(p<0.05).The C:N of both litters was very high in the study area,indicating that the nutrient release ability during litter decomposition in the two typical pine–oak forest ecosystems was relatively weak;therefore,more attention should be paid to nitrogen-fixing species and mixed forests in the GTGP area of northern China.
基金the National Key R&D Program of China (No. 2020YFC22 01000)the National Natural Science Foundation of China (No. 11927812)。
文摘Many high-precision space missions need thrusters to produce thrust with low noise to compensate for disturbances and ensure satellite platform stability. Microwave ion thruster is characterized with a wide thrust range and potential for these missions. A cost-effective and accurate mathematical model is crucial for mHz-frequency thrust noise analysis and feedback controller design. The Particle-In-Cell(PIC) and global models are two common simulation tools. The PIC model is characterized with high accuracy but huge computation cost, which is difficult to analyze long-time performance characteristics. Now, the global model is only used for the discharge chamber with low accuracy and cannot reflect ion extraction properties. In this paper, an integrative mathematical model is built for a 1-cm microwave ion thruster and can reflect ion beamlet divergence and impingement on the Accelerator Grid(AG). Simulation results show good agreement with experiments at 0.06 sccm. However, the model demonstrates worse consistency with experiments when the flux increases to 0.1 sccm, which may be because the influence of neutral gas on the Electron Cyclotron Resonance(ECR) is not considered in the model. A long-time(1000 s) simulation is conducted with this model under 35 μN. It takes 3 hrs, and the thrust noise reaches 1 μN/Hz^(0.5) at 1 mHz.
基金This work was supported by the National Natural Science Foundation of China(Grant Nos.51372042 and 51872053)the Guangdong Provincial Natural Science Foundation(Grant No.2015A030308004)+2 种基金the NSFC–Guangdong Joint Fund(Grant No.U1501246)the Dongguan City Frontier Research Project(Grant No.2019622101006)the Advanced Energy Science and Technology Guangdong Provincial Laboratory Foshan Branch-Foshan Xianhu Laboratory Open Fund-Key Project(Grant No.XHT2020-011).
文摘(Ba_(1-x)Sr_(x))(MnyTi1-y)O_(3)(BSMT)ceramics with x=35,40 mol%and y=0,0.1,0.2,0.3,0.4,0.5 mol%were prepared using a conventional solid-state reaction approach.The dielectric and ferroelectric properties were characterized using impedance analysis and polarization-electric field(P-E)hysteresis loop measurements,respectively.The adiabatic temperature drop was directly measured using a thermocouple when the applied electric field was removed.The results indicate that high permittivity and low dielectric losses were obtained by doping 0.1-0.4 mol%of manganese ions in(BaSr)TiO_(3)(BST)specimens.A maximum electrocaloric effect(ECE)of 2.75 K in temperature change with electrocaloric strength of 0.55 K·(MV/m)^(-1)was directly obtained at~21℃and 50 kV/cm in Ba_(0.6)Sr_(0.4)Mn_(0.001)Ti_(0.999)O_(3) sample,offering a promising ECE material for practical refrigeration devices working at room temperature.
基金supported by the National Natural Science Foundation of China(Grant Nos.51872053,52272105,and 52202130)the Guangdong Provincial Natural Science Foundation(Grant No.2015A030308004)+3 种基金the NSFC–Guangdong Joint Fund(Grant No.U1501246)the Dongguan City Frontier Research Project(Grant No.2019622101006)the Advanced Energy Science and Technology Guangdong Provincial Laboratory Foshan Branch–Foshan Xianhu Laboratory Open Fund-Key Project(Grant No.XHT2020-011)the Open Project Program of Guangdong Provincial Key Laboratory of Electronic Functional Materials and Devices,Huizhou University(Grant No.EFMD2022004Z).
文摘Solid-state cooling technology based on electrocaloric effect(ECE)has been advanced as an alternative to replace the vapour-compression approach to overcome the releasing of the global warming gases.However,the development in high ECE materials is still a challenge.In this work,polarization merging strategy was proposed to achieve a large ECE in xBa(Sn_(0.07)Ti_(0.93))O_(3)–(1−x)Ba(Hf_(0.1)Ti_(0.9))O_(3) ferroelectric ceramics,where x=0,0.2,0.4,0.6,0.8,and 1.Ba(Sn_(0.07)Ti_(0.93))O_(3) with an orthorhombic phase and Ba(Hf_(0.1)Ti_(0.9))O_(3) with a rhombohedral phase at room temperature were prepared beforehand as precursors,and phase-coexisted xBSnT–(1−x)BHfT ceramics were formed via a solid-state reaction approach.Phase coexisting structures were confirmed using the X-ray diffraction.The merged polarization was confirmed by the dielectric and ferroelectric properties.Optimal ECEs were obtained for 0.2BSnT–0.8BHfT ceramics,i.e.,adiabatic temperature change DT=2.16±0.08 K at 80℃and 5 MV/m,and DT=3.35±0.09 K at 80℃and 7 MV/m.
基金This work was financially supported by the Science and Technology Plan of Guangxi(Nos.AA21238001,ZY22096019,AA21077012,AA22068080,and AA23023027l)the Key R&D Program of Shandong Province(No.2022CXGC020203)+8 种基金the National Natural Science Foundation of China(Nos.12264012,62271362,and 12304120)the Young Elite Scientists Sponsorship Program by China Association for Science and Technology(CAST)(No.2021QNRC001)the Natural Science Foundation of Guangdong Province(No.2022A1515111013)the Science and Technology Plan of Guilin(Nos.2022H03 and ZY20220101)the Guangxi Key Laboratory of Manufacturing System&Advanced Manufacturing Technology(No.22-35-4-S011)the National Natural Science Foundation of China(Nos.52272105 and 52202130)the NSFC-Guangdong Joint Fund(No.U1501246)the Dongguan City Frontier Research Project(No.2019622101006)the Advanced Energy Science and Technology Guangdong Provincial Laboratory Foshan Branch-Foshan Xianhu Laboratory Open Fund-Key Project(No.XHT2020-011).
文摘The electrocaloric effect(ECE),known for its environmentally friendly characteristics,holds significant promise for advancing next-generation solid-state refrigeration technologies.Achieving a large ECE along with a wide working temperature range near room temperature remains a key developmental goal.In this study,we successfully obtained a substantial ECE of 1.78 K and an extensive working temperature range of 103 K(AT>1.52 K)near room temperature in CaZrO_(3)-modified BaTiO_(3) lead-free ferroelectric ceramics.Furthermore,this achievement was verified using direct methods.The piezoresponse force microscopy(PFM)results suggest that the broad temperature range is attributed to the formation of ferroelectric microdomains and polar nanoregions(PNRs).Furthermore,X-ray photoelectron spectroscopy(XPS)and ultraviolet-visible(UV-Vis)spectroscopy reveal a decrease in the oxygen vacancy concentration and an increase in the bandgap for higher CaZrO_(3) doping levels.These changes synergistically enhance the maximum applied electric field,helping to achieve a high-performance EcE near room temperature.This research presents a straightforward and effective approach for achieving high-performance ECEs in BaTiOg lead-free ceramics,offering promising prospects for application in next-generation solid-state refrigeration technologies.
