High pressure enables the creation of novel functional materials by modifying chemical bonding and crystal structure,opening avenues for the development of high-energy-density polynitrogen materials.We present the hig...High pressure enables the creation of novel functional materials by modifying chemical bonding and crystal structure,opening avenues for the development of high-energy-density polynitrogen materials.We present the high-pressure synthesis of three polynitrides P1 AgN7,P21/c AgN5,and P-1 AgN4,achieved through direct reactions between silver and nitrogen.Notably,the synthesis pressures required for the formation of N5 and N6 rings from metal–nitrogen reactions in this work represent the lowest values reported to date in high-pressure studies.At 15 GPa,isolated N5 rings are stabilized in P1 AgN7 and P21/c AgN5.At 26.3 GPa,P-1 AgN4 is synthesized,featuring infinite onedimensional nitrogen chains composed of alternating N2 and N6 rings,a unique catenation not observed in other polynitrides.In addition,AgN7,AgN5,and AgN4 possess significantly higher volumetric energy densities Ev than the conventional explosive TNT,making them promising high-energy-density materials.展开更多
Electrochemical conversion of CO_(2)to CO is an economically feasible method for mitigating greenhouse gas emissions.Among various electrochemical approaches,solid oxide electrolysis cells(SOECs)show high potential fo...Electrochemical conversion of CO_(2)to CO is an economically feasible method for mitigating greenhouse gas emissions.Among various electrochemical approaches,solid oxide electrolysis cells(SOECs)show high potential for CO_(2)reduction reaction(CO_(2)-RR)due to their ability to operate at high temperatures,resulting in fast reaction kinetics and increased efficiency.Considering their main energy loss is still associated with the large overpotential at the fuel electrode,the development of the highly efficient and durable cathode for SOECs has been extensively searched after.Here,we propose an A-site doping strategy to enhance the properties of Sr_(2)Fe_(1.5)Mo_(0.5)O_(6−δ)(SFM),which improve its performance as a cathode in SOECs for CO_(2)-RR,demonstrating favorable activity and durability.The structural and physiochemical characterizations,together with DFT calculations,show that the partial replacement of Sr by Bi in the SFM double perovskite not only improves CO_(2) adsorption capability at the catalyst surface but also enhances oxygen ionic conduction inside the bulk oxide,resulting in enhanced CO_(2)electrocatalysis performance in SOECs.Specifically,a La_(0.8)Sr_(0.2)Ga_(0.8)Mg_(0.2)O_(3−δ) (LSGM)electrolyte-supported single cell with the new Bi-doped SFM cathode demonstrates a large current density of 1620 mA cm^(−2) at a cell potential of 1.6 V at 850°C with good operational stability up to 200 h.Bi-doped SFM thus represents a highly promising cathode for ceramic CO_(2)electrolyzers and could accelerate our transition towards a carbon-neutral society.展开更多
Objective:To study correlation between the Xba I polymorphism of apoB gene and plasma lipid profiles in Li ethnic group.Methods:Total 1S1 cases of healthy Li people were recruited randomly by cluster sampling and 200 ...Objective:To study correlation between the Xba I polymorphism of apoB gene and plasma lipid profiles in Li ethnic group.Methods:Total 1S1 cases of healthy Li people were recruited randomly by cluster sampling and 200 Han people were recruited as control;blood was drawn to analyze Xba I polymorphism distribution of apoB gene and serum lipid levels.Results:There were lower serum total cholesterol(TC)and low density lipoprotein cholesterol(LDL-C)levels in serum of Li people;while,high density lipoprotein cholesterol(HDL-C),X^-/X^-genotype and X^+allele frequencies exhibited higher levels than Han people.Interestingly,HDL-C level was reduced,while LDL-C level was enhanced in subjects carrying heterozygous(X^-/X^-)genotype compared to homozygous(X^-/X^-)genotype.Additionally,there were no difference in serum level of triglyceride,TC,apoprotein A(apo A)and apoprotein B(apo B)between Li and Han people,the same results were showed between X^-/X^+and X^-/X^-genotype carriers.Conclusions:XbaⅠpolymorphism of apoB gene is correlated to the profiles of serum lipid level,X^-/X^+genotype carriers are phenotyped with higher LDL-C level and lower level of HDL-C in Li ethnic group.展开更多
[Objectives]To explore the use of Xiao’er Kechuanling Oral Liquid combined with Tulobuterol Patch on the basis of comprehensive treatment,compare it with the combined aerosol inhalation of terbutaline,ipratropium bro...[Objectives]To explore the use of Xiao’er Kechuanling Oral Liquid combined with Tulobuterol Patch on the basis of comprehensive treatment,compare it with the combined aerosol inhalation of terbutaline,ipratropium bromide and budesonide which are commonly used in clinic,and observe the curative effect in the treatment of acute bronchiolitis and the effect on serum IL-4 and IL-8.[Methods]80 children with acute bronchiolitis were randomly divided into observation group(n=40)and control group(n=40),and both groups were given routine comprehensive treatment.The observation group was treated with Xiao’er Kechuanling Oral Liquid combined with Tulobuterol Patch and budesonide,while the control group was treated with combined aerosol inhalation of terbutaline,ipratropium bromide and budesonide.The curative effect of the two groups was observed;the remission duration of cough,wheezing,dyspnea and nocturnal wheezing,and the disappearance time of wheezing rales and moist rales were observed in the two groups;the treatment course of intravenous infusion of methylprednisolone sodium succinate,oxygen inhalation time,sputum suction times and hospitalization time were observed in the two groups;the changes of serum IL-4 and IL-8 were observed before and after treatment in the two groups;the adverse drug reactions were observed.[Results](i)The total effective rate of the two groups was 100%(P>0.05),but the cure rate of the observation group(72.5%)was significantly higher than that of the control group(42.5%)(P<0.01).(ii)The disappearance time of cough,wheezing rales and moist rales and hospitalization time in the observation group were significantly shorter than those in the control group(P<0.01),the remission duration of nocturnal wheezing in the observation group was shorter than that in the control group(P<0.05),and the remission duration of wheezing and dyspnea in the control group was slightly longer than that in the control group(P>0.05).(iii)There was no significant difference(P>0.05)in serum IL-4 and serum IL-8 between the two groups before and after treatment.After treatment,the levels of serum IL-4 and IL-8 in the observation group and the control group were significantly lower than those before treatment in the observation group and the control group.[Conclusions]On the basis of comprehensive treatment,the use of Xiao’er Kechuanling Oral Liquid combined with Tulobuterol Patch in the treatment of acute bronchiolitis could reduce the effect of nocturnal wheezing on sleep,reduce the levels of serum IL-4 and IL-8,and significantly improve adverse symptoms.展开更多
The hybridization of fullerene and nanotube structures in newly isolated C;with the D;symmetric group(D;(1)-C;)provides an ideal model as a mediating allotrope of nanocarbon from zero-dimensional(OD)fullerene to one-d...The hybridization of fullerene and nanotube structures in newly isolated C;with the D;symmetric group(D;(1)-C;)provides an ideal model as a mediating allotrope of nanocarbon from zero-dimensional(OD)fullerene to one-dimensional nanotube.Raman and infrared spectroscopy combined with classical molecular dynamics simulation were used to investigate the structural evolution of D;(1)-C;at ambient and high pressure up to35.1 GPa.Interestingly,the high-pressure transformations of D;(1)-C;exhibit the features of both fullerene and nanotube.At around 2.5 GPa,the D;(1)-C;molecule in the crystal undergoes an orientational transition to a restricted rotation.At 6.6 GPa,the tubular hexagonal part occurs and transforms into a dumbbell-like structure at higher pressure.The material starts to amorphize above 13.9 GPa,and the transition is reversible until the pressure exceeds 25 GPa.The amorphization is probably correlated with both the intermolecular bonding and the morphology change.Our results enrich our understanding of structural changes in nano carbon from 0 D to1 D.展开更多
We investigate the behavior of the snowline in a protoplanetary disk and the relationship between the radius of the snowline and properties of molecular cloud cores.In our disk model,we consider mass influx from the g...We investigate the behavior of the snowline in a protoplanetary disk and the relationship between the radius of the snowline and properties of molecular cloud cores.In our disk model,we consider mass influx from the gravitational collapse of a molecular cloud core,irradiation from the central star,and thermal radiation from the ambient molecular cloud gas.As the protoplanetary disk evolves,the radius of the snowline increases first to a maximum value Rmax,and then decreases in the late stage of evolution of the protoplanetary disk.The value of Rmaxis dependent on the properties of molecular cloud cores(mass M;,angular velocity ω and temperature T;).Many previous works found that solid material tends to accumulate at the location of the snowline,which suggests that the snowline is the preferred location for giant planet formation.With these conclusions,we compare the values of R;with semimajor axes of giant planets in extrasolar systems,and find that Rmaxmay provide an upper limit for the locations of the formation of giant planets which are formed by the core accretion model.展开更多
Synthesis pressure and structural stability are two crucial factors for highly energetic materials,and recent investigations have indicated that cerium is an efficient catalyst for N2 reduction reactions.Here,we syste...Synthesis pressure and structural stability are two crucial factors for highly energetic materials,and recent investigations have indicated that cerium is an efficient catalyst for N2 reduction reactions.Here,we systematically explore Ce–N compounds through first-principles calculations,demonstrating that the cerium atom can weaken the strength of the N≡N bond and that a rich variety of cerium polynitrides can be formed under moderate pressure.Significantly,P1-CeN_(6) possesses the lowest synthesis pressure of 32 GPa among layered metal polynitrides owing to the strong ligand effect of cerium.The layered structure of P1-CeN_(6) proposed here consists of novel N_(14) ring.To clarify the formation mechanism of P1-CeN_(6),the reaction path Ce+3N2→trans-CeN_(6)→P1-CeN_(6) is proposed.In addition,P1-CeN_(6) possesses high hardness(20.73 GPa)and can be quenched to ambient conditions.Charge transfer between cerium atoms and N_(14) rings plays a crucial role in structural stability.Furthermore,the volumetric energy density(11.20 kJ/cm^(3))of P1-CeN_(6) is much larger than that of TNT(7.05 kJ/cm^(3)),and its detonation pressure(128.95 GPa)and detonation velocity(13.60 km/s)are respectively about seven times and twice those of TNT,and it is therefore a promising high-energy-density material.展开更多
We investigate the structural phase transitions and electronic properties of GaAs nanowires under high pressure by using synchrotron x-ray diffraction and infrared reflectance spectroscopy methods up to 26.2 GPa at ro...We investigate the structural phase transitions and electronic properties of GaAs nanowires under high pressure by using synchrotron x-ray diffraction and infrared reflectance spectroscopy methods up to 26.2 GPa at room temperature.The zinc-blende to orthorhombic phase transition was observed at around 20.0 GPa.In the same pressure range, pressureinduced metallization of GaAs nanowires was confirmed by infrared reflectance spectra.The metallization originates from the zinc-blende to orthorhombic phase transition.Decompression results demonstrated that the phase transition from zincblende to orthorhombic and the pressure-induced metallization are reversible.Compared to bulk materials, GaAs nanowires show larger bulk modulus and enhanced transition pressure due to the size effects and high surface energy.展开更多
High pressure structural phase transition of monoclinic paraotwayite type α-Ni(OH)2 nanowires with a diameter of15 nm–20 nm and a length of several micrometers were studied by synchrotron x-ray diffraction(XRD) and ...High pressure structural phase transition of monoclinic paraotwayite type α-Ni(OH)2 nanowires with a diameter of15 nm–20 nm and a length of several micrometers were studied by synchrotron x-ray diffraction(XRD) and Raman spectra.It is found that the α-Ni(OH)2 nanowires experience an isostructural phase transition associated with the amorphization of the H-sublattice of hydroxide in the interlayer spaces of the two-dimensional crystal structure at 6.3 GPa–9.3 GPa. We suggest that the isostructural phase transition can be attributed to the amorphization of the H-sublattice. The bulk moduli for the low pressure phase and the high pressure phase are 41.2(4.2) GPa and 94.4(5.6) GPa, respectively. Both the pressure-induced isostructural phase transition and the amorphization of the H-sublattice in the α-Ni(OH)2 nanowires are reversible upon decompression. Our results show that the foreign anions intercalated between the α-Ni(OH)2 layers play important roles in their structural phase transition.展开更多
In order to constrain whether the Lhasa–Qiangtang collision contributed to an early crustal thickening of the central Tibetan Plateau prior to the India–Asia collision,we present zircon LA–ICP–MS U–Pb ages,wholer...In order to constrain whether the Lhasa–Qiangtang collision contributed to an early crustal thickening of the central Tibetan Plateau prior to the India–Asia collision,we present zircon LA–ICP–MS U–Pb ages,wholerock geochemistry,and zircon Hf isotopic compositions of the newly discovered rhyolitic crystal tuffs from the Chuduoqu area in the eastern Qiangtang subterrane,central Tibet.Zircon U–Pb dating suggests that the Chuduoqu rhyolitic crystal tuffs were emplaced at ca.68 Ma.The Chuoduoqu rhyolitic crystal tuffs display high SiO_(2)and K2 O,and low MgO,Cr,and Ni.Combined with their zircon Hf isotopic data,we suggest that they were derived from partial melting of the juvenile lower crust,and the magma underwent fractional crystallization and limited upper continental crustal assimilation during its evolution prior to eruption.They should be formed in a post-collisional environment related to lithospheric mantle delamination.The Chuduoqu rhyolitic crystal tuffs could provide important constraints on the Late Cretaceous crustal thickening of the central Tibetan Plateau caused by the Lhasa–Qiangtang collision.展开更多
Nanog is a recently discovered homeodomain transcription factor that sustains the pluripotency of embryonic stem （ES） cells and blocks their differentiation into endoderm. The murine F9 embryonal carcinoma cell line...Nanog is a recently discovered homeodomain transcription factor that sustains the pluripotency of embryonic stem （ES） cells and blocks their differentiation into endoderm. The murine F9 embryonal carcinoma cell line is a well-documented model system for endoderm cell lineage differentiation. Here, we examined the function of Nanog in F9 cell endoderm differentiation. Over-expression of Nanog returns the F9 cells to the early status of ES cells and represses the differentiation of primitive endoderm and parietal endoderm in F9 cells, whereas it has no effect on the differentiation of visceral endoderm. In contrast, the expression of C-terminal domain-truncated Nanog spontaneously promotes endoderm differentiation in F9 cells. These data suggest that Nanog is required to sustain the proper undifferentiated status of F9 cells, and the C-terminal domain of Nanog transduces the most effects in repressing primitive endoderm and parietal endoderm differentiation in F9 cells.展开更多
Pentazolate compounds have attracted extensive attention as high energy density materials.The synthesis and recovery of pentazolate compounds is of great importance for their potential applications.Here,we report the ...Pentazolate compounds have attracted extensive attention as high energy density materials.The synthesis and recovery of pentazolate compounds is of great importance for their potential applications.Here,we report the synthesis of Pmn2_(1)-NaN_(5)and Pm-Na_(2)N_(5)through compressing and laser heating pure NaN_(3)at~60 GPa.Upon decompression,the pressureinduced structural transition from Pmn2_(1)-NaN_(5)into Cm-NaN_(5)is observed in the pressure range of 14-23 GPa for the first time.The cyclo-N_(5)^(-)can be traced down to 4.7 GPa at room temperature and recovered to ambient pressure under low temperature condition(up to 160 K).The Pm-Na_(2)N_(5)is suggested to decompose into the P4/mmm-NaN_(2)at 23 GPa,and be stable at ambient conditions.This work provides insight into the high-pressure behaviors of pentazolate compounds and an alternative way to stabilize energetic polynitrogen compounds.展开更多
Background:Gut microbiota exert an immense effect on host health and host environmental adaptation.Furthermore,the composition and structure of gut microbiota are determined by the environment and host genetic factors...Background:Gut microbiota exert an immense effect on host health and host environmental adaptation.Furthermore,the composition and structure of gut microbiota are determined by the environment and host genetic factors.However,the relative contribution of the environment and host genetic factors toward shaping the structure of gut microbiota has been poorly understood.Methods:In this study,we characterized the fecal microbial communities of the closely related voles Neodon fuscus,Lasiopodomys brandtii,and L.mandarinus after caged feeding in the laboratory for 6 months,through high-throughput sequencing and bioinformatics analysis.Results:The results of pairwise comparisons of N.fuscus vs.L.brandtii and L.mandarinus vs.L.brandtii revealed significant differences in bacterial diversity and composition after domestication.While 991 same operational taxonomic units(OTUs)were shared in three voles,there were 362,291,and 303 species-specific OTUs in N.fuscus,L.brandtii,and L.mandarinus,respectively.The relative abundances of Proteobacteria and Prevotella,which are reported to be enriched in high-altitude populations,were significantly higher in high-altitude N.fuscus than in low-altitude L.brandtii after domestication.Firmicutes,which produce various digestive enzymes for energy metabolism,and Spirochaetes,which can degrade cellulose,were found in higher abundance in subterranean L.mandarinus than that in L.brandtii which dwells on the earth surface.Conclusion:Our findings showed that some components of gut microbiota still maintained dominance even when different host species are reared under the same environmental conditions,suggesting that these bacteria are substantially influenced by host factors.展开更多
We propose a feasible strategy of intercepting the layered polymeric nitrogen(LP-N)and hexagonal layered polymeric nitrogen(HLP-N)at ambient conditions by using the confinement templates.The stable mechanism of confin...We propose a feasible strategy of intercepting the layered polymeric nitrogen(LP-N)and hexagonal layered polymeric nitrogen(HLP-N)at ambient conditions by using the confinement templates.The stable mechanism of confined LP-N and HLP-N at ambient conditions is revealed.展开更多
We propose a new CaN4 high pressure structure with the P21/m space group.The P21/m-CaN4 structure is constituted by the infinite armchair N-chain.The dynamical stability and mechanical stability are verified by the ca...We propose a new CaN4 high pressure structure with the P21/m space group.The P21/m-CaN4 structure is constituted by the infinite armchair N-chain.The dynamical stability and mechanical stability are verified by the calculations of phonon dispersion curves and elastic constants.The enthalpy difference calculation shows that the P21/m phase is more stable than the reported P41212 phase.The advantaged properties of P21/m-CaN4,such as high nitrogen content(58.3%) and low polymerization pressure(18.3 GPa),allow it to be a potential high energy materlal.Band structure calculation shows that the P21/m-CaN4 structure is a metallic phase.The nonpolar covalent single N-N bond is a sigma bond.The charge transfer between the Ca and N atoms results in an ionic bond interaction.展开更多
基金supported by the National Key R&D Program of China(Grant No.2023YFA1406200)the National Natural Science Foundation of China(NSFC)(Grant Nos.12174143 and 12404014)the Basic Science Center Project of the NSFC(Grant No.52388201).
文摘High pressure enables the creation of novel functional materials by modifying chemical bonding and crystal structure,opening avenues for the development of high-energy-density polynitrogen materials.We present the high-pressure synthesis of three polynitrides P1 AgN7,P21/c AgN5,and P-1 AgN4,achieved through direct reactions between silver and nitrogen.Notably,the synthesis pressures required for the formation of N5 and N6 rings from metal–nitrogen reactions in this work represent the lowest values reported to date in high-pressure studies.At 15 GPa,isolated N5 rings are stabilized in P1 AgN7 and P21/c AgN5.At 26.3 GPa,P-1 AgN4 is synthesized,featuring infinite onedimensional nitrogen chains composed of alternating N2 and N6 rings,a unique catenation not observed in other polynitrides.In addition,AgN7,AgN5,and AgN4 possess significantly higher volumetric energy densities Ev than the conventional explosive TNT,making them promising high-energy-density materials.
基金financially supported by the State Key Laboratory of Clean Energy Utilization(Open Fund Project No.ZJUCEU2021001)Natural Science Foundation of Jiangsu Province(No.BK20221312).
文摘Electrochemical conversion of CO_(2)to CO is an economically feasible method for mitigating greenhouse gas emissions.Among various electrochemical approaches,solid oxide electrolysis cells(SOECs)show high potential for CO_(2)reduction reaction(CO_(2)-RR)due to their ability to operate at high temperatures,resulting in fast reaction kinetics and increased efficiency.Considering their main energy loss is still associated with the large overpotential at the fuel electrode,the development of the highly efficient and durable cathode for SOECs has been extensively searched after.Here,we propose an A-site doping strategy to enhance the properties of Sr_(2)Fe_(1.5)Mo_(0.5)O_(6−δ)(SFM),which improve its performance as a cathode in SOECs for CO_(2)-RR,demonstrating favorable activity and durability.The structural and physiochemical characterizations,together with DFT calculations,show that the partial replacement of Sr by Bi in the SFM double perovskite not only improves CO_(2) adsorption capability at the catalyst surface but also enhances oxygen ionic conduction inside the bulk oxide,resulting in enhanced CO_(2)electrocatalysis performance in SOECs.Specifically,a La_(0.8)Sr_(0.2)Ga_(0.8)Mg_(0.2)O_(3−δ) (LSGM)electrolyte-supported single cell with the new Bi-doped SFM cathode demonstrates a large current density of 1620 mA cm^(−2) at a cell potential of 1.6 V at 850°C with good operational stability up to 200 h.Bi-doped SFM thus represents a highly promising cathode for ceramic CO_(2)electrolyzers and could accelerate our transition towards a carbon-neutral society.
基金supported by natural science foundation of Hainan province.Haikou,China(No.30726)
文摘Objective:To study correlation between the Xba I polymorphism of apoB gene and plasma lipid profiles in Li ethnic group.Methods:Total 1S1 cases of healthy Li people were recruited randomly by cluster sampling and 200 Han people were recruited as control;blood was drawn to analyze Xba I polymorphism distribution of apoB gene and serum lipid levels.Results:There were lower serum total cholesterol(TC)and low density lipoprotein cholesterol(LDL-C)levels in serum of Li people;while,high density lipoprotein cholesterol(HDL-C),X^-/X^-genotype and X^+allele frequencies exhibited higher levels than Han people.Interestingly,HDL-C level was reduced,while LDL-C level was enhanced in subjects carrying heterozygous(X^-/X^-)genotype compared to homozygous(X^-/X^-)genotype.Additionally,there were no difference in serum level of triglyceride,TC,apoprotein A(apo A)and apoprotein B(apo B)between Li and Han people,the same results were showed between X^-/X^+and X^-/X^-genotype carriers.Conclusions:XbaⅠpolymorphism of apoB gene is correlated to the profiles of serum lipid level,X^-/X^+genotype carriers are phenotyped with higher LDL-C level and lower level of HDL-C in Li ethnic group.
基金Supported by Scientific Research Project of the Department of Health of Guangxi Zhuang Autonomous Region(Z2015215)Development,Popularization and Application Project of Appropriate Medical and HealthTechnology in Guangxi(S2018015).
文摘[Objectives]To explore the use of Xiao’er Kechuanling Oral Liquid combined with Tulobuterol Patch on the basis of comprehensive treatment,compare it with the combined aerosol inhalation of terbutaline,ipratropium bromide and budesonide which are commonly used in clinic,and observe the curative effect in the treatment of acute bronchiolitis and the effect on serum IL-4 and IL-8.[Methods]80 children with acute bronchiolitis were randomly divided into observation group(n=40)and control group(n=40),and both groups were given routine comprehensive treatment.The observation group was treated with Xiao’er Kechuanling Oral Liquid combined with Tulobuterol Patch and budesonide,while the control group was treated with combined aerosol inhalation of terbutaline,ipratropium bromide and budesonide.The curative effect of the two groups was observed;the remission duration of cough,wheezing,dyspnea and nocturnal wheezing,and the disappearance time of wheezing rales and moist rales were observed in the two groups;the treatment course of intravenous infusion of methylprednisolone sodium succinate,oxygen inhalation time,sputum suction times and hospitalization time were observed in the two groups;the changes of serum IL-4 and IL-8 were observed before and after treatment in the two groups;the adverse drug reactions were observed.[Results](i)The total effective rate of the two groups was 100%(P>0.05),but the cure rate of the observation group(72.5%)was significantly higher than that of the control group(42.5%)(P<0.01).(ii)The disappearance time of cough,wheezing rales and moist rales and hospitalization time in the observation group were significantly shorter than those in the control group(P<0.01),the remission duration of nocturnal wheezing in the observation group was shorter than that in the control group(P<0.05),and the remission duration of wheezing and dyspnea in the control group was slightly longer than that in the control group(P>0.05).(iii)There was no significant difference(P>0.05)in serum IL-4 and serum IL-8 between the two groups before and after treatment.After treatment,the levels of serum IL-4 and IL-8 in the observation group and the control group were significantly lower than those before treatment in the observation group and the control group.[Conclusions]On the basis of comprehensive treatment,the use of Xiao’er Kechuanling Oral Liquid combined with Tulobuterol Patch in the treatment of acute bronchiolitis could reduce the effect of nocturnal wheezing on sleep,reduce the levels of serum IL-4 and IL-8,and significantly improve adverse symptoms.
基金supported fnancially by the National Key R&D Program of China(Grant No.2018YFA0305900)the National Natural Science Foundation of China(Grant Nos.12011530063 and 51822204)+3 种基金supported by NSF(DMR-0805056EAR 06–49658,COMPRES)DOE/NNSA(DE-FC03-03N00144,CDAC)supported by the DOE/BES(DEAC02-98CH10886)。
文摘The hybridization of fullerene and nanotube structures in newly isolated C;with the D;symmetric group(D;(1)-C;)provides an ideal model as a mediating allotrope of nanocarbon from zero-dimensional(OD)fullerene to one-dimensional nanotube.Raman and infrared spectroscopy combined with classical molecular dynamics simulation were used to investigate the structural evolution of D;(1)-C;at ambient and high pressure up to35.1 GPa.Interestingly,the high-pressure transformations of D;(1)-C;exhibit the features of both fullerene and nanotube.At around 2.5 GPa,the D;(1)-C;molecule in the crystal undergoes an orientational transition to a restricted rotation.At 6.6 GPa,the tubular hexagonal part occurs and transforms into a dumbbell-like structure at higher pressure.The material starts to amorphize above 13.9 GPa,and the transition is reversible until the pressure exceeds 25 GPa.The amorphization is probably correlated with both the intermolecular bonding and the morphology change.Our results enrich our understanding of structural changes in nano carbon from 0 D to1 D.
基金supported by the National Natural Science Foundation of China (Grant No. 11504150)
文摘We investigate the behavior of the snowline in a protoplanetary disk and the relationship between the radius of the snowline and properties of molecular cloud cores.In our disk model,we consider mass influx from the gravitational collapse of a molecular cloud core,irradiation from the central star,and thermal radiation from the ambient molecular cloud gas.As the protoplanetary disk evolves,the radius of the snowline increases first to a maximum value Rmax,and then decreases in the late stage of evolution of the protoplanetary disk.The value of Rmaxis dependent on the properties of molecular cloud cores(mass M;,angular velocity ω and temperature T;).Many previous works found that solid material tends to accumulate at the location of the snowline,which suggests that the snowline is the preferred location for giant planet formation.With these conclusions,we compare the values of R;with semimajor axes of giant planets in extrasolar systems,and find that Rmaxmay provide an upper limit for the locations of the formation of giant planets which are formed by the core accretion model.
基金This work was supported financially by the National Key R&D Program of China(Grant Nos.2018YFA0305900 and 2018YFA0703404)the National Natural Science Foundation of China under Grant Nos.21905159,11634004,51320105007,11604116,and 51602124,the Program for Changjiang Scholars and Innovative Research Team in the University of the Ministry of Education of China under Grant No.IRT1132+1 种基金the Higher Educational Youth Innovation Science and Technology Program Shandong Province(Grant No.2022KJ183)GHfund B(Grant No.202202026143).
文摘Synthesis pressure and structural stability are two crucial factors for highly energetic materials,and recent investigations have indicated that cerium is an efficient catalyst for N2 reduction reactions.Here,we systematically explore Ce–N compounds through first-principles calculations,demonstrating that the cerium atom can weaken the strength of the N≡N bond and that a rich variety of cerium polynitrides can be formed under moderate pressure.Significantly,P1-CeN_(6) possesses the lowest synthesis pressure of 32 GPa among layered metal polynitrides owing to the strong ligand effect of cerium.The layered structure of P1-CeN_(6) proposed here consists of novel N_(14) ring.To clarify the formation mechanism of P1-CeN_(6),the reaction path Ce+3N2→trans-CeN_(6)→P1-CeN_(6) is proposed.In addition,P1-CeN_(6) possesses high hardness(20.73 GPa)and can be quenched to ambient conditions.Charge transfer between cerium atoms and N_(14) rings plays a crucial role in structural stability.Furthermore,the volumetric energy density(11.20 kJ/cm^(3))of P1-CeN_(6) is much larger than that of TNT(7.05 kJ/cm^(3)),and its detonation pressure(128.95 GPa)and detonation velocity(13.60 km/s)are respectively about seven times and twice those of TNT,and it is therefore a promising high-energy-density material.
基金Project supported by the National Key R&D Program of China(Grant No.2018YFA0305900)the National Natural Science Foundation of China(Grant No.11604116)+1 种基金Beijing Municipal Natural Science Foundation,China(Grant No.1192017)Youth Innovation Promotion Association,Chinese Academy of Sciences(Grant No.2017156)
文摘We investigate the structural phase transitions and electronic properties of GaAs nanowires under high pressure by using synchrotron x-ray diffraction and infrared reflectance spectroscopy methods up to 26.2 GPa at room temperature.The zinc-blende to orthorhombic phase transition was observed at around 20.0 GPa.In the same pressure range, pressureinduced metallization of GaAs nanowires was confirmed by infrared reflectance spectra.The metallization originates from the zinc-blende to orthorhombic phase transition.Decompression results demonstrated that the phase transition from zincblende to orthorhombic and the pressure-induced metallization are reversible.Compared to bulk materials, GaAs nanowires show larger bulk modulus and enhanced transition pressure due to the size effects and high surface energy.
基金Project supported by the National Key Research and Development Program of China(Grant No.2018YFA0305900)the National Natural Science Foundation of China(Grant Nos.11874172,11374120,11634004,and 51320105007)the Fund from Jilin University for Science and Technology Innovative Research Team(Grant No.2017TD-01)
文摘High pressure structural phase transition of monoclinic paraotwayite type α-Ni(OH)2 nanowires with a diameter of15 nm–20 nm and a length of several micrometers were studied by synchrotron x-ray diffraction(XRD) and Raman spectra.It is found that the α-Ni(OH)2 nanowires experience an isostructural phase transition associated with the amorphization of the H-sublattice of hydroxide in the interlayer spaces of the two-dimensional crystal structure at 6.3 GPa–9.3 GPa. We suggest that the isostructural phase transition can be attributed to the amorphization of the H-sublattice. The bulk moduli for the low pressure phase and the high pressure phase are 41.2(4.2) GPa and 94.4(5.6) GPa, respectively. Both the pressure-induced isostructural phase transition and the amorphization of the H-sublattice in the α-Ni(OH)2 nanowires are reversible upon decompression. Our results show that the foreign anions intercalated between the α-Ni(OH)2 layers play important roles in their structural phase transition.
基金funded by the National Natural Science Foundation of China(41272093)the Geological Survey Project(12120114080901)of China Geological Survey+4 种基金the Self-determined Foundation of Key Laboratory of Mineral Resources Evaluation in Northeast Asia,Ministry of Natural Resources(DBY-ZZ-19-04)the Shandong Provincial Natural Science Foundation of China(No.ZR2019PD017)the Natural Science Foundation of Liaoning Province(2020-BS-258)the Department of Education of Liaoning Province(LJ2020JCL010)a Discipline Innovation Team Project of Liaoning Technical University(LNTU20TD-14)。
文摘In order to constrain whether the Lhasa–Qiangtang collision contributed to an early crustal thickening of the central Tibetan Plateau prior to the India–Asia collision,we present zircon LA–ICP–MS U–Pb ages,wholerock geochemistry,and zircon Hf isotopic compositions of the newly discovered rhyolitic crystal tuffs from the Chuduoqu area in the eastern Qiangtang subterrane,central Tibet.Zircon U–Pb dating suggests that the Chuduoqu rhyolitic crystal tuffs were emplaced at ca.68 Ma.The Chuoduoqu rhyolitic crystal tuffs display high SiO_(2)and K2 O,and low MgO,Cr,and Ni.Combined with their zircon Hf isotopic data,we suggest that they were derived from partial melting of the juvenile lower crust,and the magma underwent fractional crystallization and limited upper continental crustal assimilation during its evolution prior to eruption.They should be formed in a post-collisional environment related to lithospheric mantle delamination.The Chuduoqu rhyolitic crystal tuffs could provide important constraints on the Late Cretaceous crustal thickening of the central Tibetan Plateau caused by the Lhasa–Qiangtang collision.
文摘Nanog is a recently discovered homeodomain transcription factor that sustains the pluripotency of embryonic stem （ES） cells and blocks their differentiation into endoderm. The murine F9 embryonal carcinoma cell line is a well-documented model system for endoderm cell lineage differentiation. Here, we examined the function of Nanog in F9 cell endoderm differentiation. Over-expression of Nanog returns the F9 cells to the early status of ES cells and represses the differentiation of primitive endoderm and parietal endoderm in F9 cells, whereas it has no effect on the differentiation of visceral endoderm. In contrast, the expression of C-terminal domain-truncated Nanog spontaneously promotes endoderm differentiation in F9 cells. These data suggest that Nanog is required to sustain the proper undifferentiated status of F9 cells, and the C-terminal domain of Nanog transduces the most effects in repressing primitive endoderm and parietal endoderm differentiation in F9 cells.
基金Project supported by the National Key R&D Program of China(Grant No.2018YFA0305900)the National Nat-ural Science Foundation of China(Grant Nos.12174143,11634004,11847094,and 11804384)JLU Science and Technology Innovative Research Team(Grant No.2017TD-01)。
文摘Pentazolate compounds have attracted extensive attention as high energy density materials.The synthesis and recovery of pentazolate compounds is of great importance for their potential applications.Here,we report the synthesis of Pmn2_(1)-NaN_(5)and Pm-Na_(2)N_(5)through compressing and laser heating pure NaN_(3)at~60 GPa.Upon decompression,the pressureinduced structural transition from Pmn2_(1)-NaN_(5)into Cm-NaN_(5)is observed in the pressure range of 14-23 GPa for the first time.The cyclo-N_(5)^(-)can be traced down to 4.7 GPa at room temperature and recovered to ambient pressure under low temperature condition(up to 160 K).The Pm-Na_(2)N_(5)is suggested to decompose into the P4/mmm-NaN_(2)at 23 GPa,and be stable at ambient conditions.This work provides insight into the high-pressure behaviors of pentazolate compounds and an alternative way to stabilize energetic polynitrogen compounds.
基金National Natural Science Foundation of ChinaGrant/Award Number:U2004152+3 种基金China Postdoctoral Science FoundationGrant/Award Number:2020M672264Zhongyuan Science and Technology Innovation Leading Talent ProjectGrant/Award Number:224200510001。
文摘Background:Gut microbiota exert an immense effect on host health and host environmental adaptation.Furthermore,the composition and structure of gut microbiota are determined by the environment and host genetic factors.However,the relative contribution of the environment and host genetic factors toward shaping the structure of gut microbiota has been poorly understood.Methods:In this study,we characterized the fecal microbial communities of the closely related voles Neodon fuscus,Lasiopodomys brandtii,and L.mandarinus after caged feeding in the laboratory for 6 months,through high-throughput sequencing and bioinformatics analysis.Results:The results of pairwise comparisons of N.fuscus vs.L.brandtii and L.mandarinus vs.L.brandtii revealed significant differences in bacterial diversity and composition after domestication.While 991 same operational taxonomic units(OTUs)were shared in three voles,there were 362,291,and 303 species-specific OTUs in N.fuscus,L.brandtii,and L.mandarinus,respectively.The relative abundances of Proteobacteria and Prevotella,which are reported to be enriched in high-altitude populations,were significantly higher in high-altitude N.fuscus than in low-altitude L.brandtii after domestication.Firmicutes,which produce various digestive enzymes for energy metabolism,and Spirochaetes,which can degrade cellulose,were found in higher abundance in subterranean L.mandarinus than that in L.brandtii which dwells on the earth surface.Conclusion:Our findings showed that some components of gut microbiota still maintained dominance even when different host species are reared under the same environmental conditions,suggesting that these bacteria are substantially influenced by host factors.
基金financially supported by the National Key R&D Program of China(Grant No.2018YFA0305900)the National Natural Science Foundation of China(Grant Nos.12174143 and U2032215)the Natural Science Foundation Project of Liaoning Province(Grant No.2022-MS-377)。
文摘We propose a feasible strategy of intercepting the layered polymeric nitrogen(LP-N)and hexagonal layered polymeric nitrogen(HLP-N)at ambient conditions by using the confinement templates.The stable mechanism of confined LP-N and HLP-N at ambient conditions is revealed.
基金Supported by the National Key Technology Research and Development Program of China under Grant No.2018YFA0305900the National Natural Science Foundation of China under Grant Nos.11634004,51320105007,11604116 and 51602124the Program for Changjiang Scholars and Innovative Research Team in University of Ministry of Education of China under Grant No.IRT1132.
文摘We propose a new CaN4 high pressure structure with the P21/m space group.The P21/m-CaN4 structure is constituted by the infinite armchair N-chain.The dynamical stability and mechanical stability are verified by the calculations of phonon dispersion curves and elastic constants.The enthalpy difference calculation shows that the P21/m phase is more stable than the reported P41212 phase.The advantaged properties of P21/m-CaN4,such as high nitrogen content(58.3%) and low polymerization pressure(18.3 GPa),allow it to be a potential high energy materlal.Band structure calculation shows that the P21/m-CaN4 structure is a metallic phase.The nonpolar covalent single N-N bond is a sigma bond.The charge transfer between the Ca and N atoms results in an ionic bond interaction.
