We report a novel double-shelled nanoboxes photocatalyst architecture with tailored interfaces that accelerate quantum efficiency for photocatalytic CO_(2) reduction reaction(CO_(2)RR)via Mo–S bridging bonds sites in...We report a novel double-shelled nanoboxes photocatalyst architecture with tailored interfaces that accelerate quantum efficiency for photocatalytic CO_(2) reduction reaction(CO_(2)RR)via Mo–S bridging bonds sites in S_(v)–In_(2)S_(3)@2H–MoTe_(2).The X-ray absorption near-edge structure shows that the formation of S_(v)–In_(2)S_(3)@2H–MoTe_(2) adjusts the coordination environment via interface engineering and forms Mo–S polarized sites at the interface.The interfacial dynamics and catalytic behavior are clearly revealed by ultrafast femtosecond transient absorption,time-resolved,and in situ diffuse reflectance–Infrared Fourier transform spectroscopy.A tunable electronic structure through steric interaction of Mo–S bridging bonds induces a 1.7-fold enhancement in S_(v)–In_(2)S_(3)@2H–MoTe_(2)(5)photogenerated carrier concentration relative to pristine S_(v)–In_(2)S_(3).Benefiting from lower carrier transport activation energy,an internal quantum efficiency of 94.01%at 380 nm was used for photocatalytic CO_(2)RR.This study proposes a new strategy to design photocatalyst through bridging sites to adjust the selectivity of photocatalytic CO_(2)RR.展开更多
The Hot Dry Rock(HDR)is considered as a clean and renewable energy,poised to significantly contribute to the global energy decarbonization agenda.Many HDR projects worldwide have accumulated valuable experience in eff...The Hot Dry Rock(HDR)is considered as a clean and renewable energy,poised to significantly contribute to the global energy decarbonization agenda.Many HDR projects worldwide have accumulated valuable experience in efficient drilling and completion,reservoir construction,and fracture simulation.In 2019,China Geological Survey(CGS)initiated a demonstration project of HDR exploration and production in the Gonghe Basin,aiming to overcome the setbacks faced by HDR projects.Over the ensuing four years,the Gonghe HDR project achieved the first power generation in 2021,followed by the second power generation test in 2022.After establishing the primary well group in the initial phase,two directional wells and one branch well were drilled.Noteworthy progress was made in successfully constructing the targeted reservoir,realizing inter-well connectivity,power generation and grid connection,implementing of the real-time micro-seismic monitoring.A closed-loop technical validation of the HDR exploration and production was completed.However,many technical challenges remain in the process of HDR industrialization,such as reservoir fracture network characterization,efficient drilling and completion,multiple fracturing treatment,continuous injection and production,as well as mitigation of induced seismicity and numerical simulation technology.展开更多
Proliferation and differentiation of intestinal stem cell(ISC)to replace damaged gut mucosal epithelial cells in inflammatory states is a critical step in ameliorating gut inflammation.However,when this disordered pro...Proliferation and differentiation of intestinal stem cell(ISC)to replace damaged gut mucosal epithelial cells in inflammatory states is a critical step in ameliorating gut inflammation.However,when this disordered proliferation continues,it induces the ISC to enter a cancerous state.The gut microbiota on the free surface of the gut mucosal barrier is able to interact with ISC on a sustained basis.Micro-biota metabolites are able to regulate the proliferation of gut stem and progenitor cells through transcription factors,while in steady state,differentiated colono-cytes are able to break down such metabolites,thereby protecting stem cells at the gut crypt.In the future,the gut flora and its metabolites mediating the regulation of ISC differentiation will be a potential treatment for enteropathies.展开更多
Intermittent new energy delivery requires increasing the flexibility of ultra-high voltage direct current(DC)power adjustment.Based on a converter steady-state model and a DC power model,the control angle constraints ...Intermittent new energy delivery requires increasing the flexibility of ultra-high voltage direct current(DC)power adjustment.Based on a converter steady-state model and a DC power model,the control angle constraints of a converter valve are relaxed for power regulation.In this paper,a flexible DC power control method based on a fixed tap changer position is proposed.The initial ratio of the converter transformer is optimized.The effects of the fixed-tap changer position control on the control angle,reactive power compensation,and commutation failure are analyzed.The new control method allows a DC system to operate at a large angle and increase the additional reactive power loss while improving the commutation security margin.Steady-state and electromagnetic transient simulations in the CIGRE test system verify the validity of the method proposed in this paper and the correctness of the analysis conclusions.展开更多
This paper presents a subspace identification method for closed-loop systems with unknown deterministic disturbances.To deal with the unknown deterministic disturbances,two strategies are implemented to construct the ...This paper presents a subspace identification method for closed-loop systems with unknown deterministic disturbances.To deal with the unknown deterministic disturbances,two strategies are implemented to construct the row space that can be used to approximately represent the unknown deterministic disturbances using the trigonometric functions or Bernstein polynomials depending on whether the disturbance frequencies are known.For closed-loop identification,CCF-N4SID is extended to the case with unknown deterministic disturbances using the oblique projection.In addition,a proper Bernstein polynomial order can be determined using the Akaike information criterion(AIC)or the Bayesian information criterion(BIC).Numerical simulation results demonstrate the effectiveness of the proposed identification method for both periodic and aperiodic deterministic disturbances.展开更多
Hot dry rock(HDR)is a kind of clean energy with significant potential.Since the 1970s,the United States,Japan,France,Australia,and other countries have attempted to conduct several HDR development research projects to...Hot dry rock(HDR)is a kind of clean energy with significant potential.Since the 1970s,the United States,Japan,France,Australia,and other countries have attempted to conduct several HDR development research projects to extract thermal energy by breaking through key technologies.However,up to now,the development of HDR is still in the research,development,and demonstration stage.An HDR exploration borehole(with 236℃ at a depth of 3705 m)was drilled into Triassic granite in the Gonghe Basin in northwest China in 2017.Subsequently,China Geological Survey(CGS)launched the HDR resources exploration and production demonstration project in 2019.After three years of efforts,a sequence of significant technological breakthroughs have been made,including the genetic model of deep heat sources,directional drilling and well completion in high-temperature hard rock,large-scale reservoir stimulation,reservoir characterization,and productivity evaluation,reservoir connectivity and flow circulation,efficient thermoelectric conversion,monitoring,and geological risk assessment,etc.Then the whole-process technological system for HDR exploration and production has been preliminarily established accordingly.The first power generation test was completed in November 2021.The results of this project will provide scientific support for HDR development and utilization in the future.展开更多
Programmed DNA double-strand break(DSB)formation is a crucial step in meiotic recombination,yet techniques for highefficiency and precise mapping of the 3’ends of DSBs are still in their infancy.Here,we report a nove...Programmed DNA double-strand break(DSB)formation is a crucial step in meiotic recombination,yet techniques for highefficiency and precise mapping of the 3’ends of DSBs are still in their infancy.Here,we report a novel technique,named DNA End tailing and sequencing(DEtail-seq),which can directly and ultra-efficiently characterize the 3’ends of meiotic DSBs with near single-nucleotide resolution in a variety of species,including yeast,mouse,and human.We find that the 3’ends of meiotic DSBs are stable without significant resection in budding yeast.Meiotic DSBs are strongly enriched in de novo H3K4me3 peaks in the mouse genome at leptotene stage.We also profile meiotic DSBs in human and find DSB hotspots are enriched near the common fragile sites during human meiosis,especially at CCCTC-binding factor(CTCF)-associated enhancers.Therefore,DEtail-seq provides a powerful method to detect DSB ends in various species,and our results provide new insights into the distribution and regulation of meiotic DSB hotspots.展开更多
Here we report a TiHfNbTa bulk medium-entropy alloy(MEA)superconductor crystallized in the body-centered cubic structure with the unit cell parameter a=3.35925?,which is synthesized by an arc melting method.Supercondu...Here we report a TiHfNbTa bulk medium-entropy alloy(MEA)superconductor crystallized in the body-centered cubic structure with the unit cell parameter a=3.35925?,which is synthesized by an arc melting method.Superconducting properties of the TiHfNbTa are studied by employing magnetic susceptibility,resistivity,and specific heat measurements.Experimental results show a bulk superconducting transition temperature(Tc)of around 6.75 K.The lower and upper critical fields for TiHfNbTa are45.8 m T and 10.46 T,respectively.First-principles calculations show that the d electrons of Ti,Hf,Nb,and Ta are the main contribution to the total density of states near the Fermi level.Our results indicate that the superconductivity is a conventional swave type with extremely strong coupling(△C_(el)/γ_(n)T_(c)=2.88,2△_(0)/k_(B)T_(c)=5.02,and λ_(ep)=2.77).The extremely strong coupling behavior in the s-wave type Ti Hf Nb Ta MEA superconductor is unusual because it generally happens in cuprates,pnictides,and other unconventional superconductors.展开更多
This essay, through comparing venture capital in China＇s modernization with U.S.A., Japan, summarizes the different characteristics of venture capital of the United States and Japan, and thinks that China＇s present ...This essay, through comparing venture capital in China＇s modernization with U.S.A., Japan, summarizes the different characteristics of venture capital of the United States and Japan, and thinks that China＇s present modernization, as a flag of developing countries, has already entered middle period of industrialization, according to the experience of U.S.A., Japan and reality of China. The technological progress mode has already been changed from technology import to technological innovation stage at this time. In order to encourage innovations, we must develop venture capital in a more effective manner. The national conditions have determined the technology import of China, which must start with a high points, this is the most important condition of target to choose. The venture capital of China in system transitional period should use U.S.A.＇s experience for reference even more on the capital source to pay close attention to the capital sources of the government and bank. Once the government guides and starts the market, the folk capital will show the natural instinct of the capital automatically Risk investment is the embodiment capitalized personality spirit, in order to dispose such ambitious culture. We need the reform of the system as well as dispose risk investor＇s stratum at present.展开更多
Background： Intermittent hypoxia （IH） is a key element of obstructive sleep apnea （OSA） that can lead to disorders in the liver. In this study, IH was established in a rat model to examine its effects on the expr...Background： Intermittent hypoxia （IH） is a key element of obstructive sleep apnea （OSA） that can lead to disorders in the liver. In this study, IH was established in a rat model to examine its effects on the expression of hepatic cytochrome P450 （CYP） and CYP regulators, including nuclear receptors. Methods： Hematoxylin and eosin staining was conducted to analyze the general pathology of the liver of rats exposed to IH. The messenger RNA （mRNA） expression levels of inflammatory cytokines, CYPs, nuclear factor-κB （NF-κB）, and nuclear factors in the liver were measured by quantitative reverse transcription polymerase chain reaction. Results： We found inflammatory infiltrates in the liver of rats exposed to IH. The mRNA expression level of interleukin-1beta was increased in the liver of the IH-exposed rats （0.005 ± 0.001 vs. 0.038 ± 0.008, P = 0.042）, whereas the mRNA expression level of Cyp1a2 was downregulated （0.022 ± 0.002 vs. 0.0050 ± 0.0002, P = 0.029）. The hepatic level of transcription factor NF-κB was also reduced in the IH group relative to that in the control group, but the difference was not statistically significant and was parallel to the expression of the pregnane X receptor and constitutive androstane receptor. However, the decreased expression of the glucocorticoid receptor upon IH treatment was statistically significant （0.056 ± 0.012 vs. 0.032 ± 0.005, P = 0.035）. Conclusions： These results indicate a decrease in expression of hepatic CYPs and their regulator GR in rats exposed to IH. Therefore, this should be noted for patients on medication, especially those on drugs metabolized via the hepatic system, and close attention should be paid to the liver function of patients with OSA-associated IH.展开更多
Objective:The aim of this study is to discover the possible working mechanisms of Ardisiae Japonicae Herba(AJH)on hepatoma carcinoma(HCC).Methods:In this study,ethanol extract of AJH was prepared and used to treat HCC...Objective:The aim of this study is to discover the possible working mechanisms of Ardisiae Japonicae Herba(AJH)on hepatoma carcinoma(HCC).Methods:In this study,ethanol extract of AJH was prepared and used to treat HCC cell in vitro.Furthermore,a genomic wide RNA sequencing(RNA-seq)was performed to screen deregulated genes in HCC cells after the treatment of AJH extract.The gene and protein expression related to lipid metabolism in HCC cells were also investigated to validate the results obtained from RNA-seq.Results:AJH extract could inhibit HCC cell proliferation in vitro.RNA-seq analysis has identified 1,601 differentially expressed genes(DEGs,fold change≥2.0 or fold change≤0.5,P<0.05)in HCC after AJH extract treatment,which included 225 up-regulated genes and 1,376 down-regulated genes.KEGG pathway analysis of DEGs demonstrated that lipid metabolism was a potential pathway related to AJH treatment.In agreement with the RNA-seq data,q PCR and Western-blot analysis indicated that expression of genes and proteins related to lipid metabolism(SREBP1,ACC,ACLY and FASN)were significantly downregulated in AJH treatment group as compared with the control group.Furthermore,AJH extract could also decrease lipid contents and cellular free fatty acid levels in HCC cells.Conclusion:Ethanol extract of AJH could inhibit HCC cell proliferation in vitro,the possible mechanism may be related to the inhibition of lipid metabolism.展开更多
R-loops are chromatin structures consisting of anRNA:DNA hybrid and the other single-stranded DNA,which widely exist among genomes from bacteria to higher eukaryotes and participate in a variety of biological processe...R-loops are chromatin structures consisting of anRNA:DNA hybrid and the other single-stranded DNA,which widely exist among genomes from bacteria to higher eukaryotes and participate in a variety of biological processes(Zhou et al.,2022).Currently,a variety of approaches to detect genome-wide R-loops have been developed,and ssDRIP-seq(single-strand DNA ligation-based library preparation from DNA:RNA hybrid immunoprecipitation,followed by sequencing)is one of the widely utilized methods(Xu et al.,2022).However,there are many limitations to genome-wide R-loop mapping based on high-throughput methods.For example,the activity of restriction enzymes for genomic DNA fragmentation.展开更多
Chemical doping is a critical factor in the development of new superconductors or optimizing the superconducting transition temperature(T_(c))of the parent superconducting materials.Here,a new simple urea approach is ...Chemical doping is a critical factor in the development of new superconductors or optimizing the superconducting transition temperature(T_(c))of the parent superconducting materials.Here,a new simple urea approach is developed to synthesize the N-dopedα-Mo_(2)C.Benefiting from the simple urea method,a broad superconducting dome is found in the Mo_(2)C_(1−x)N_(x)(0≤x≤0.49)compositions.X-ray diffraction results show that the structure of𝛼α-Mo_(2)C remains unchanged and there is a variation of lattice parameters with nitrogen doping.Resistivity,magnetic susceptibility,and heat capacity measurement results confirm that T_(c)was strongly increased from 2.68K(x=0)to 7.05K(x=0.49).First-principles calculations and our analysis indicate that increasing nitrogen doping leads to a rise in the density of states at the Fermi level and doping-induced phonon softening,which enhances electron–phonon coupling.This results in an increase in𝑇T_(c)and a sharp rise in the upper critical field.Our findings provide a promising strategy for fabricating transition metal carbonitrides and provide a material platform for further study of the superconductivity of transition metal carbides.展开更多
This research investigated a pavement system on steel bridge decks that use epoxy resin(EP)bonded ultra-high performance concrete(UHPC).Through FEM analysis and static and dynamic bending fatigue tests of the composit...This research investigated a pavement system on steel bridge decks that use epoxy resin(EP)bonded ultra-high performance concrete(UHPC).Through FEM analysis and static and dynamic bending fatigue tests of the composite structure,the influences of the interface of the pavement layer,reinforcement,and different paving materials on the structural performance were compared and analyzed.The results show that the resin bonded UHPC pavement structure can reduce the weld strain in the steel plate by about 32%and the relative deflection between ribs by about 52%under standard axial load conditions compared to traditional pavements.The EP bonding layer can nearly double the drawing strength of the pavement interface from 1.3 MPa,and improve the bending resistance of the UHPC structure on steel bridge decks by about 50%;the bending resistance of reinforced UHPC structures is twice that of unreinforced UHPC structure,and the dynamic deflection of the UHPC pavement structure increases exponentially with increasing fatigue load.The fatigue life is about 1.2×10^(7) cycles under a fixed force of 9 kN and a dynamic deflection of 0.35 mm,which meets the requirements for fatigue performance of pavements on steel bridge decks under traffic conditions of large flow and heavy load.展开更多
A synergistic catalysis combination of chiral-at-metal rhodium complex and amine catalyst was developed for enantioselective alkylation of aldehydes with α,β-unsaturated 2-acyl imidazoles. The corresponding adducts ...A synergistic catalysis combination of chiral-at-metal rhodium complex and amine catalyst was developed for enantioselective alkylation of aldehydes with α,β-unsaturated 2-acyl imidazoles. The corresponding adducts were obtained in good yields with excellent enantioselectivities （up to 99% ee）.展开更多
基金the Natural Science Foundation of China(11922415,12274471)Guangdong Basic and Applied Basic Research Foundation(2022A1515011168,2019A1515011718,2019A1515011337)the Key Research and Development Program of Guangdong Province,China(2019B110209003).
文摘We report a novel double-shelled nanoboxes photocatalyst architecture with tailored interfaces that accelerate quantum efficiency for photocatalytic CO_(2) reduction reaction(CO_(2)RR)via Mo–S bridging bonds sites in S_(v)–In_(2)S_(3)@2H–MoTe_(2).The X-ray absorption near-edge structure shows that the formation of S_(v)–In_(2)S_(3)@2H–MoTe_(2) adjusts the coordination environment via interface engineering and forms Mo–S polarized sites at the interface.The interfacial dynamics and catalytic behavior are clearly revealed by ultrafast femtosecond transient absorption,time-resolved,and in situ diffuse reflectance–Infrared Fourier transform spectroscopy.A tunable electronic structure through steric interaction of Mo–S bridging bonds induces a 1.7-fold enhancement in S_(v)–In_(2)S_(3)@2H–MoTe_(2)(5)photogenerated carrier concentration relative to pristine S_(v)–In_(2)S_(3).Benefiting from lower carrier transport activation energy,an internal quantum efficiency of 94.01%at 380 nm was used for photocatalytic CO_(2)RR.This study proposes a new strategy to design photocatalyst through bridging sites to adjust the selectivity of photocatalytic CO_(2)RR.
基金Funded by the“Investigation and Evaluation of the Hot Dry Rock Resources in the Guide-Dalianhai Area of the Gonghe Basin,Qinghai”(DD20211336,DD20211337,DD20211338)“Hot Dry Rock Resources Exploration and Production Demonstration Project”(DD20230018)of the China Geological Survey。
文摘The Hot Dry Rock(HDR)is considered as a clean and renewable energy,poised to significantly contribute to the global energy decarbonization agenda.Many HDR projects worldwide have accumulated valuable experience in efficient drilling and completion,reservoir construction,and fracture simulation.In 2019,China Geological Survey(CGS)initiated a demonstration project of HDR exploration and production in the Gonghe Basin,aiming to overcome the setbacks faced by HDR projects.Over the ensuing four years,the Gonghe HDR project achieved the first power generation in 2021,followed by the second power generation test in 2022.After establishing the primary well group in the initial phase,two directional wells and one branch well were drilled.Noteworthy progress was made in successfully constructing the targeted reservoir,realizing inter-well connectivity,power generation and grid connection,implementing of the real-time micro-seismic monitoring.A closed-loop technical validation of the HDR exploration and production was completed.However,many technical challenges remain in the process of HDR industrialization,such as reservoir fracture network characterization,efficient drilling and completion,multiple fracturing treatment,continuous injection and production,as well as mitigation of induced seismicity and numerical simulation technology.
基金Supported by Scientific Research Fund Project of Education Department of Yunnan Province,No.2023J0346the Kunming Health Commission Kunming Health Science and Technology Personnel Training Project,No.2021-SW-75the Medical and Health Science and Technology Project of Kunming Health Committee,No.2022-03-09-008.
文摘Proliferation and differentiation of intestinal stem cell(ISC)to replace damaged gut mucosal epithelial cells in inflammatory states is a critical step in ameliorating gut inflammation.However,when this disordered proliferation continues,it induces the ISC to enter a cancerous state.The gut microbiota on the free surface of the gut mucosal barrier is able to interact with ISC on a sustained basis.Micro-biota metabolites are able to regulate the proliferation of gut stem and progenitor cells through transcription factors,while in steady state,differentiated colono-cytes are able to break down such metabolites,thereby protecting stem cells at the gut crypt.In the future,the gut flora and its metabolites mediating the regulation of ISC differentiation will be a potential treatment for enteropathies.
基金an independent research project from the Shandong Electric Power Research Institute,“Research on the control method of DC power under fixed converter transformer tap-changer position”(ZY-2020-01)Based on the achievement,a national invention patent(No.2020112240143)has been applied.
文摘Intermittent new energy delivery requires increasing the flexibility of ultra-high voltage direct current(DC)power adjustment.Based on a converter steady-state model and a DC power model,the control angle constraints of a converter valve are relaxed for power regulation.In this paper,a flexible DC power control method based on a fixed tap changer position is proposed.The initial ratio of the converter transformer is optimized.The effects of the fixed-tap changer position control on the control angle,reactive power compensation,and commutation failure are analyzed.The new control method allows a DC system to operate at a large angle and increase the additional reactive power loss while improving the commutation security margin.Steady-state and electromagnetic transient simulations in the CIGRE test system verify the validity of the method proposed in this paper and the correctness of the analysis conclusions.
基金partially supported by National Key Research and Development Program of China(2019YFC1510902)National Natural Science Foundation of China(62073104)+1 种基金Natural Science Foundation of Heilongjiang Province(LH2022F024)China Postdoctoral Science Foundation(2022M710965)。
文摘This paper presents a subspace identification method for closed-loop systems with unknown deterministic disturbances.To deal with the unknown deterministic disturbances,two strategies are implemented to construct the row space that can be used to approximately represent the unknown deterministic disturbances using the trigonometric functions or Bernstein polynomials depending on whether the disturbance frequencies are known.For closed-loop identification,CCF-N4SID is extended to the case with unknown deterministic disturbances using the oblique projection.In addition,a proper Bernstein polynomial order can be determined using the Akaike information criterion(AIC)or the Bayesian information criterion(BIC).Numerical simulation results demonstrate the effectiveness of the proposed identification method for both periodic and aperiodic deterministic disturbances.
基金funded by the“Hot Dry Rock Resources Exploration and Production Demonstration Project”of the China Geological Survey(DD20190131,DD20190135,DD20211336).
文摘Hot dry rock(HDR)is a kind of clean energy with significant potential.Since the 1970s,the United States,Japan,France,Australia,and other countries have attempted to conduct several HDR development research projects to extract thermal energy by breaking through key technologies.However,up to now,the development of HDR is still in the research,development,and demonstration stage.An HDR exploration borehole(with 236℃ at a depth of 3705 m)was drilled into Triassic granite in the Gonghe Basin in northwest China in 2017.Subsequently,China Geological Survey(CGS)launched the HDR resources exploration and production demonstration project in 2019.After three years of efforts,a sequence of significant technological breakthroughs have been made,including the genetic model of deep heat sources,directional drilling and well completion in high-temperature hard rock,large-scale reservoir stimulation,reservoir characterization,and productivity evaluation,reservoir connectivity and flow circulation,efficient thermoelectric conversion,monitoring,and geological risk assessment,etc.Then the whole-process technological system for HDR exploration and production has been preliminarily established accordingly.The first power generation test was completed in November 2021.The results of this project will provide scientific support for HDR development and utilization in the future.
基金supported by the National Natural Science Foundation of China (91740105,31822028,32071437,31900302)Central Public-interest Scientific Institution Basal Research Fund (Y2022QC33)。
文摘Programmed DNA double-strand break(DSB)formation is a crucial step in meiotic recombination,yet techniques for highefficiency and precise mapping of the 3’ends of DSBs are still in their infancy.Here,we report a novel technique,named DNA End tailing and sequencing(DEtail-seq),which can directly and ultra-efficiently characterize the 3’ends of meiotic DSBs with near single-nucleotide resolution in a variety of species,including yeast,mouse,and human.We find that the 3’ends of meiotic DSBs are stable without significant resection in budding yeast.Meiotic DSBs are strongly enriched in de novo H3K4me3 peaks in the mouse genome at leptotene stage.We also profile meiotic DSBs in human and find DSB hotspots are enriched near the common fragile sites during human meiosis,especially at CCCTC-binding factor(CTCF)-associated enhancers.Therefore,DEtail-seq provides a powerful method to detect DSB ends in various species,and our results provide new insights into the distribution and regulation of meiotic DSB hotspots.
基金supported by the National Natural Science Foundation of China(Grant Nos.12274471,and 11922415)the Guangdong Basic and Applied Basic Research Foundation(Grant Nos.2022A1515011168,and 2019A1515011718)+6 种基金the Key Research and Development Program of Guangdong Province,China(Grant No.2019B110209003)supported by the Foreign Young Talents Program of China(Grant No.22KW041C211)supported by the Key-Area Research and Development Program of Guangdong Province(Grant No.2020B0101340002)supported by the NKRDPC(Grant Nos.2022YFA1402802,and 2018YFA0306001)the National Natural Science Foundation of China(Grant Nos.11974432,and 92165204)the Leading Talent Program of Guangdong Special Projects(Grant No.201626003)the Shenzhen International Quantum Academy(Grant No.SIQA202102)。
文摘Here we report a TiHfNbTa bulk medium-entropy alloy(MEA)superconductor crystallized in the body-centered cubic structure with the unit cell parameter a=3.35925?,which is synthesized by an arc melting method.Superconducting properties of the TiHfNbTa are studied by employing magnetic susceptibility,resistivity,and specific heat measurements.Experimental results show a bulk superconducting transition temperature(Tc)of around 6.75 K.The lower and upper critical fields for TiHfNbTa are45.8 m T and 10.46 T,respectively.First-principles calculations show that the d electrons of Ti,Hf,Nb,and Ta are the main contribution to the total density of states near the Fermi level.Our results indicate that the superconductivity is a conventional swave type with extremely strong coupling(△C_(el)/γ_(n)T_(c)=2.88,2△_(0)/k_(B)T_(c)=5.02,and λ_(ep)=2.77).The extremely strong coupling behavior in the s-wave type Ti Hf Nb Ta MEA superconductor is unusual because it generally happens in cuprates,pnictides,and other unconventional superconductors.
文摘This essay, through comparing venture capital in China＇s modernization with U.S.A., Japan, summarizes the different characteristics of venture capital of the United States and Japan, and thinks that China＇s present modernization, as a flag of developing countries, has already entered middle period of industrialization, according to the experience of U.S.A., Japan and reality of China. The technological progress mode has already been changed from technology import to technological innovation stage at this time. In order to encourage innovations, we must develop venture capital in a more effective manner. The national conditions have determined the technology import of China, which must start with a high points, this is the most important condition of target to choose. The venture capital of China in system transitional period should use U.S.A.＇s experience for reference even more on the capital source to pay close attention to the capital sources of the government and bank. Once the government guides and starts the market, the folk capital will show the natural instinct of the capital automatically Risk investment is the embodiment capitalized personality spirit, in order to dispose such ambitious culture. We need the reform of the system as well as dispose risk investor＇s stratum at present.
文摘Background： Intermittent hypoxia （IH） is a key element of obstructive sleep apnea （OSA） that can lead to disorders in the liver. In this study, IH was established in a rat model to examine its effects on the expression of hepatic cytochrome P450 （CYP） and CYP regulators, including nuclear receptors. Methods： Hematoxylin and eosin staining was conducted to analyze the general pathology of the liver of rats exposed to IH. The messenger RNA （mRNA） expression levels of inflammatory cytokines, CYPs, nuclear factor-κB （NF-κB）, and nuclear factors in the liver were measured by quantitative reverse transcription polymerase chain reaction. Results： We found inflammatory infiltrates in the liver of rats exposed to IH. The mRNA expression level of interleukin-1beta was increased in the liver of the IH-exposed rats （0.005 ± 0.001 vs. 0.038 ± 0.008, P = 0.042）, whereas the mRNA expression level of Cyp1a2 was downregulated （0.022 ± 0.002 vs. 0.0050 ± 0.0002, P = 0.029）. The hepatic level of transcription factor NF-κB was also reduced in the IH group relative to that in the control group, but the difference was not statistically significant and was parallel to the expression of the pregnane X receptor and constitutive androstane receptor. However, the decreased expression of the glucocorticoid receptor upon IH treatment was statistically significant （0.056 ± 0.012 vs. 0.032 ± 0.005, P = 0.035）. Conclusions： These results indicate a decrease in expression of hepatic CYPs and their regulator GR in rats exposed to IH. Therefore, this should be noted for patients on medication, especially those on drugs metabolized via the hepatic system, and close attention should be paid to the liver function of patients with OSA-associated IH.
基金supported by a grant from the Natural Science Foundation of Tianjin(No.17JCYBJC42800)National Natural Science Fundation of China(No.81560772,81703828)。
文摘Objective:The aim of this study is to discover the possible working mechanisms of Ardisiae Japonicae Herba(AJH)on hepatoma carcinoma(HCC).Methods:In this study,ethanol extract of AJH was prepared and used to treat HCC cell in vitro.Furthermore,a genomic wide RNA sequencing(RNA-seq)was performed to screen deregulated genes in HCC cells after the treatment of AJH extract.The gene and protein expression related to lipid metabolism in HCC cells were also investigated to validate the results obtained from RNA-seq.Results:AJH extract could inhibit HCC cell proliferation in vitro.RNA-seq analysis has identified 1,601 differentially expressed genes(DEGs,fold change≥2.0 or fold change≤0.5,P<0.05)in HCC after AJH extract treatment,which included 225 up-regulated genes and 1,376 down-regulated genes.KEGG pathway analysis of DEGs demonstrated that lipid metabolism was a potential pathway related to AJH treatment.In agreement with the RNA-seq data,q PCR and Western-blot analysis indicated that expression of genes and proteins related to lipid metabolism(SREBP1,ACC,ACLY and FASN)were significantly downregulated in AJH treatment group as compared with the control group.Furthermore,AJH extract could also decrease lipid contents and cellular free fatty acid levels in HCC cells.Conclusion:Ethanol extract of AJH could inhibit HCC cell proliferation in vitro,the possible mechanism may be related to the inhibition of lipid metabolism.
基金supported by the Science and Technology Program of Inner Mongolia Autonomous Region of China (2021GG0307,2020GG0126)the Science and Technology Major Project of Inner Mongolia Autonomous Region of China (2021ZD0011-1).
基金supported by the Digitalization,Development,and Application of Biotic Resource Project(202002AA100007 to C.Z.)the National Natural Science Foundation of China(grant nos.31822028 and 91940306 to Q.S.and 32100428 to J.Z.)and the Ministry of Science and Technology of the People’s Republic of China(2016YFA0500800 to Q.S.).We greatly appreciate the useful discussions by all the members from the Zhang lab and the Sun lab.The Zhang Lab is supported by the Yunnan Young&Elite Talents Project(YNWR-QNBJ-2019-268).J.Z.is supported by the postdoctoral fellowship from Tsinghua-Peking Center for Life Sciences.
文摘R-loops are chromatin structures consisting of anRNA:DNA hybrid and the other single-stranded DNA,which widely exist among genomes from bacteria to higher eukaryotes and participate in a variety of biological processes(Zhou et al.,2022).Currently,a variety of approaches to detect genome-wide R-loops have been developed,and ssDRIP-seq(single-strand DNA ligation-based library preparation from DNA:RNA hybrid immunoprecipitation,followed by sequencing)is one of the widely utilized methods(Xu et al.,2022).However,there are many limitations to genome-wide R-loop mapping based on high-throughput methods.For example,the activity of restriction enzymes for genomic DNA fragmentation.
基金supported by the National Natural Science Foundation of China(Grant Nos.12274471 and 11922415)Guangdong Basic and Applied Basic Research Foundation(Grant No.2022A1515011168)+3 种基金the Key Research&Development Program of Guangdong Province,China(Grant No.2019B110209003)the Guangdong Provincial Key Laboratory of Magnetoelectric Physics and Devices(Grant Nos.2022B1212010008)Lingyong Zeng was supported by the Postdoctoral Fellowship Program of CPSF(Grant Nos.GZC20233299)Fundamental Research Funds for the Central Universities,Sun Yat-Sen University(Grant Nos.29000-31610058)。
文摘Chemical doping is a critical factor in the development of new superconductors or optimizing the superconducting transition temperature(T_(c))of the parent superconducting materials.Here,a new simple urea approach is developed to synthesize the N-dopedα-Mo_(2)C.Benefiting from the simple urea method,a broad superconducting dome is found in the Mo_(2)C_(1−x)N_(x)(0≤x≤0.49)compositions.X-ray diffraction results show that the structure of𝛼α-Mo_(2)C remains unchanged and there is a variation of lattice parameters with nitrogen doping.Resistivity,magnetic susceptibility,and heat capacity measurement results confirm that T_(c)was strongly increased from 2.68K(x=0)to 7.05K(x=0.49).First-principles calculations and our analysis indicate that increasing nitrogen doping leads to a rise in the density of states at the Fermi level and doping-induced phonon softening,which enhances electron–phonon coupling.This results in an increase in𝑇T_(c)and a sharp rise in the upper critical field.Our findings provide a promising strategy for fabricating transition metal carbonitrides and provide a material platform for further study of the superconductivity of transition metal carbides.
基金This work is jointly supported by the Natural Science Foundation of Jiangsu Province(Nos.BK20180113 and BK20181112)the Jiangsu Provincial Programme for High-Level Talents in Six Areas(No.XCL-CXTD-007)+1 种基金the Youth Programme of National Natural Science Foundation of China(Grant No.51908285)the Transformation Project of Scientific and Technological Achievements of Qinghai Province(No.2017-SF-134).
文摘This research investigated a pavement system on steel bridge decks that use epoxy resin(EP)bonded ultra-high performance concrete(UHPC).Through FEM analysis and static and dynamic bending fatigue tests of the composite structure,the influences of the interface of the pavement layer,reinforcement,and different paving materials on the structural performance were compared and analyzed.The results show that the resin bonded UHPC pavement structure can reduce the weld strain in the steel plate by about 32%and the relative deflection between ribs by about 52%under standard axial load conditions compared to traditional pavements.The EP bonding layer can nearly double the drawing strength of the pavement interface from 1.3 MPa,and improve the bending resistance of the UHPC structure on steel bridge decks by about 50%;the bending resistance of reinforced UHPC structures is twice that of unreinforced UHPC structure,and the dynamic deflection of the UHPC pavement structure increases exponentially with increasing fatigue load.The fatigue life is about 1.2×10^(7) cycles under a fixed force of 9 kN and a dynamic deflection of 0.35 mm,which meets the requirements for fatigue performance of pavements on steel bridge decks under traffic conditions of large flow and heavy load.
文摘A synergistic catalysis combination of chiral-at-metal rhodium complex and amine catalyst was developed for enantioselective alkylation of aldehydes with α,β-unsaturated 2-acyl imidazoles. The corresponding adducts were obtained in good yields with excellent enantioselectivities （up to 99% ee）.
