This study presents a fully coupled thermo-hydro-mechanical (THM) constitutive model for clay rocks. The model is formulated within the elastic-viscoplasticity framework, which considers nonlinearity and softening aft...This study presents a fully coupled thermo-hydro-mechanical (THM) constitutive model for clay rocks. The model is formulated within the elastic-viscoplasticity framework, which considers nonlinearity and softening after peak strength, anisotropy of stiffness and strength, as well as permeability variation due to damage. In addition, the mechanical properties are coupled with thermal phenomena and accumulated plastic strains. The adopted nonlocal and viscoplastic approaches enhance numerical efficiency and provide the possibility to simulate localization phenomena. The model is validated against experimental data from laboratory tests conducted on Callovo-Oxfordian (COx) claystone samples that are initially unsaturated and under suction. The tests include a thermal phase where the COx specimens are subjected to different temperature increases. A good agreement with experimental data is obtained. In addition, parametric analyses are carried out to investigate the influence of the hydraulic boundary conditions (B.C.) and post-failure behavior models on the THM behavior evolution. It is shown that different drainage conditions affect the thermally induced pore pressures that, in turn, influence the onset of softening. The constitutive model presented constitutes a promising approach for simulating the most important features of the THM behavior of clay rocks. It is a tool with a high potential for application to several relevant case studies, such as thermal fracturing analysis of nuclear waste disposal systems.展开更多
Green and atom-economic depolymerization of lignin remains a great challenge due toits complex non-repetitive structure and the inert property for chemo-digestion. A redoxneutrallignin depolymerization system without ...Green and atom-economic depolymerization of lignin remains a great challenge due toits complex non-repetitive structure and the inert property for chemo-digestion. A redoxneutrallignin depolymerization system without the use of extra oxidant and/or reductantover a Co-NC catalyst has been developed in this work, providing the first non-noble metalheterogeneous catalytic system for redox-neutral valorization of lignin. Mechanistic studiesbased on control reactions and deuterium labeling experiments suggest that the reactionproceeds via ametal-catalyzed dehydrogenation of C_(α)-OH to afford a carbonyl intermediate,followed by C_(β)-O bond cleavage (via hydrogenolysis) to afford monophenols and aromaticketone products. The hydrogen used for the cleavage of the C_(β)-O bond originates from thealcoholmoiety in the substrate, and the cascade dehydrogenation and hydrogenolysis stepsare highly coupled, rendering it an efficient and atom-economic process.展开更多
The effect of prenatal exposure to ambient particulate matter(PM)on birth weight varies considerably across studies,and the findings remain inconclusive.In this study,we conducted a meta-analysis to assess the associa...The effect of prenatal exposure to ambient particulate matter(PM)on birth weight varies considerably across studies,and the findings remain inconclusive.In this study,we conducted a meta-analysis to assess the associations between exposure to PM_(2.5) and PM10 and birth weight.A total of 74 studies were identified through searches in Web of Science,PubMed,Embase,and Ovid Medline,as well as manual searches,up to October 2024.We found that for each 10μg/m^(3) increase in PM_(2.5),the risk of low birth weight(LBW)increased significantly during the entire pregnancy(odds ratio[OR]=2.41,95%confidence interval[CI]:1.99–2.91)and in all trimesters.Similarly,for every 10μg/m^(3) increase in PM10 concentration,the risk of LBW increased significantly during the entire pregnancy(OR=1.46,95%CI:1.16–1.84).Subgroup analysis by maternal age for PM_(2.5) showed that mothers aged 30 and above had a significantly higher risk of LBW(OR=3.69,95%CI:2.81–4.84),compared with those under 30.In conclusion,maternal exposure to PM_(2.5) and PM_(10) is associated with an increased risk of LBW across all trimesters.Additionally,mothers aged 30 and above are at a higher risk of LBW,compared with younger mothers.Further research is needed to clarify the biological mechanisms by which PM pollution may contribute to LBW.展开更多
The seepage of groundwater and the strain-softening of rock mass in a submarine tunnel expand the plastic region of rock,thereby affecting its overall stability.It is therefore essential to study the stress and strain...The seepage of groundwater and the strain-softening of rock mass in a submarine tunnel expand the plastic region of rock,thereby affecting its overall stability.It is therefore essential to study the stress and strain fields in the rocks surrounding the submarine tunnel by considering the coupled effect of strainsoftening and seepage.However,the evolution equation for the hydro-mechanical parameters in the existing fully coupled solution is a uniform equation that is unable to reproduce the characteristics of rock mass in practice.In this study,an updated numerical procedure for the submarine tunnel is derived by coupling strain-softening and seepage effect based on the experimental results.According to the hydro-mechanical coupling theory,the hydro-mechanical parameters such as elastic modulus,Poisson's ratio,Biot's coefficient and permeability coefficient of rocks are characterized by the fitting equations derived from the experimental data.Then,the updated numerical procedure is deduced with the governing equations,boundary conditions,seepage equations and fitting equations.The updated numerical procedure is verified accurately compared with the previous analytical solution.By utilizing the updated numerical procedure,the characteristics of stress field and the influences of initial pore water pressure,Biot's coefficient,and permeability coefficient on the stress,displacement and water-inflow of the surrounding rocks are discussed.Regardless of the variations in hydro-mechanical parameters,the stress distribution has a similar trend.The initial permeability coefficient exerts the most significant influence on the stress field.With the increases in initial pore water pressure and Biot's coefficient,the plastic region expands,and the water-inflow and displacement increase accordingly.Given the fact that the stability of the tunnel is more sensitive to the seepage force controlled by the hydraulic parameters,it is suggested to dewater the ground above the submarine tunnel to control the initial pore water pressure.展开更多
N-participated lignin depolymerization is of great importance for the transformation of waste lignin into value-added chemicals.The vast majority of developed strategies employ organic amines as nitrogen source,and co...N-participated lignin depolymerization is of great importance for the transformation of waste lignin into value-added chemicals.The vast majority of developed strategies employ organic amines as nitrogen source,and considerablemethods rely on excessive use of strong base,which suffers severe environmental issues.Herein,benzonitrile derivatives are synthesized from oxidized ligninβ-O-4 model compounds in the presence of solid nitrogen source(NH_(4))_(2)CO_(3)under mild,base-free conditions over commercially available copper catalyst.Mechanism studies suggest the transformation undergoes a one-pot,highly coupled cascade reaction path involving oxidative C-C bond cleavage and in-situ formation of C≡N bond.Of which,Cu(OAc)2 catalyzes the transfer of hydrogen from C_(β)(C_(β)-H)to C_(α),leading to the cleavage of C_(α)-C_(β)bonds to offer benzaldehyde derivative,this intermediate then reacts in-situ with(NH_(4))_(2)CO_(3)to afford the targeted aromatic nitrile product.Tetrabutylammonium iodide(TBAI),acting as a promoter,plays a key role in breaking the C_(α)-C_(β)bonds to form the intermediate benzaldehyde derivative.With this protocol,the feasibility of the production of value-added syringonitrile from birchwood lignin has been demonstrated.This transformation provides a sustainable approach to benzonitrile chemicals from renewable source of lignin.展开更多
Biodegradable magnesium(Mg)alloys exhibit excellent biocompatibility,adequate mechanical properties,and osteogenic effect.They can contribute to complete recovery of damaged tissues without concerns about a second sur...Biodegradable magnesium(Mg)alloys exhibit excellent biocompatibility,adequate mechanical properties,and osteogenic effect.They can contribute to complete recovery of damaged tissues without concerns about a second surgery and have achieved clinical applications in orthopedic and cardiovascular fields.Porous scaffolds can provide functions such as bone integration and adjustable mechanical properties,thus widely used for bone repair.Additive manufacturing(AM)offers the advantages of design freedom and high precision,enabling the reliable production of porous scaffolds with customized structures.The combination of biodegradable Mg alloys,porous scaffolds,and AM processes has created tremendous opportunities for the precision treatment of bone defects.This article reviews the current development in the additive manufacturing process and design of Mg alloy biodegradable orthopedic implants,fo-cusing on chemical compositions,structural design,surface treatment,and their effects on mechanical properties,degradation behavior,and biocompatibility.Finally,the future perspective of porous Mg alloy biodegradable orthopedic implants is proposed.展开更多
Laser powder bed fusion(L-PBF)has been employed to additively manufacture WE43 magnesium(Mg)alloy biodegradable implants,but WE43 L-PBF samples exhibit excessively rapid corrosion.In this work,dense WE43 L-PBF samples...Laser powder bed fusion(L-PBF)has been employed to additively manufacture WE43 magnesium(Mg)alloy biodegradable implants,but WE43 L-PBF samples exhibit excessively rapid corrosion.In this work,dense WE43 L-PBF samples were built with the relativity density reaching 99.9%.High temperature oxidation was performed on the L-PBF samples in circulating air via various heating temperatures and holding durations.The oxidation and diffusion at the elevated temperature generated a gradient structure composed of an oxide layer at the surface,a transition layer in the middle and the matrix.The oxide layer consisted of rare earth(RE)oxides,and became dense and thick with increasing the holding duration.The matrix was composed ofα-Mg,RE oxides and Mg_(24)RE_(5) precipitates.The precipitates almost disappeared in the transition layer.Enhanced passivation effect was observed in the samples treated by a suitable high temperature oxidation.The original L-PBF samples lost 40%weight after 3-day immersion in Hank’s solution,and broke into fragments after 7-day immersion.The casted and solution treated samples lost roughly half of the weight after 28-day immersion.The high temperature oxidation samples,which were heated at 525℃ for 8 h,kept the structural integrity,and lost only 6.88%weight after 28-day immersion.The substantially improved corrosion resistance was contributed to the gradient structure at the surface.On one hand,the outmost dense layer of RE oxides isolated the corrosive medium;on the other hand,the transition layer considerably inhibited the corrosion owing to the lack of precipitates.Overall,high temperature oxidation provides an efficient,economic and safe approach to inhibit the corrosion of WE43 L-PBF samples,and has promising prospects for future clinical applications.展开更多
Laser powder bed fusion(L-PBF)has been used to fabricate biodegradable Mg implants of WE43 alloy,but the degradation is too fast compared with the term bone reconstruction.Previous studies show that high temperature o...Laser powder bed fusion(L-PBF)has been used to fabricate biodegradable Mg implants of WE43 alloy,but the degradation is too fast compared with the term bone reconstruction.Previous studies show that high temperature oxidation(HTO)can successfully inhibit the degradation of WE43 alloy.In this work,the influence of HTO on L-PBF samples of WE43 alloy was investigated regarding tensile,compressive,and abrasive resistance,as well as in vitro cytotoxicity,cell proliferation,hemolysis,and osteogenesis.Compared with the as-built L-PBF samples,HTO increased grain size and grain texture,stabilized and coarsened precipitates,and caused discontinuous static recrystallization in the matrix.The oxide layer at the surface of the HTO samples improved surface roughness,hydrophilia,hardness,and abrasive resis-tance.The tensile strength decreased slightly from 292 to 265 MPa,while the elongation substantially increased from 10.97%to 16.58%after HTO.The in vitro cell viability,cell proliferation,hemolysis,and osteogenic effect were considerably enhanced due to the improvement of surface quality and the initial inhibition of excessive Mg^(2+)releasement.Overall,HTO is of great benefit to the surface performance,ductility,and biocompatibility of WE43 alloy fabricated by L-PBF for biodegradable applications.展开更多
A Johann-type X-ray spectrometer was successfully developed at the hard X-ray branch(in-vacuum undulator with a 24-mm periodic length)of the energy material beamline(E-line)at the Shanghai Synchrotron Radiation Facili...A Johann-type X-ray spectrometer was successfully developed at the hard X-ray branch(in-vacuum undulator with a 24-mm periodic length)of the energy material beamline(E-line)at the Shanghai Synchrotron Radiation Facility(SSRF).This spectrometer was utilized to implement X-ray emission spectroscopy(XES),high-energy resolution fluorescence-detected X-ray absorption spectroscopy(HERFD-XAS),and resonant inelastic X-ray scattering.Seven spherically bent crystals were positioned on the respective vertical 500-mm-diameter Rowland circles,adopting an area detector to increase the solid angle to 1.75%of 4πsr,facilitating the study of low-concentrate systems under complex reaction conditions.Operated under the atmosphere pressure,the spectrometer covers the energy region from 3.5 to 18 keV,with the Bragg angle ranging from 73°to 86°during vertical scanning.It offers a promised energy resolution of sub-eV(XES)and super-eV(HERFD-XAS).Generally,these comprehensive core-level spectroscopy methods based on hard X-rays at the E-line with an extremely high photon flux can meet the crucial requirements of a green energy strategy.Moreover,they provide substantial support for scientific advances in fundamental research.展开更多
Monosescinol A(1),the first example of sesquiterpene–polycyclic polyprenylated acylphloroglucinol(PPAP)adduct,which represented a new subclass of PPAP-type natural products,along with two new congeners with normal sp...Monosescinol A(1),the first example of sesquiterpene–polycyclic polyprenylated acylphloroglucinol(PPAP)adduct,which represented a new subclass of PPAP-type natural products,along with two new congeners with normal spiro 6/6/5 tricyclic architecture,were isolated from Hypericum longistylum.Monosescinol A possessed an unprecedented 6/5/5/6/6 pentacyclic carbon skeleton that might be assembled from the 6/6/5 carbon skeleton,via the splitting decomposition of C-3/C-14,and the attack from the C-3 in the PPAP core to C-28 in sesquiterpene section.In addition,we have firstly confirmed that 24R configuration was existed in sec–Bu containing PPAPs by single crystal diffraction data analysis of monosescinol B(2),that might provide an enlightenment in the configurational determination of sec–Bu containing PPAPs.Significantly,further pharmacological research has found that compound 1 exhibited remarkable pharmacological effects against acute myeloid leukemia(AML)cell lines,with direct inhibition of mitochondrial complex V and an increase in mitochondrial membrane potential,and led to an induction of oxidative stress,endogenous inflammation,and apoptosis of AML cells.展开更多
基金funded by the European Union's Horizon 2020 research and innovation programme under a grant agreement (Grant No.847593)partially supported by the Fundamental Research Funds for the Central Universities (Grant No.22120240029).
文摘This study presents a fully coupled thermo-hydro-mechanical (THM) constitutive model for clay rocks. The model is formulated within the elastic-viscoplasticity framework, which considers nonlinearity and softening after peak strength, anisotropy of stiffness and strength, as well as permeability variation due to damage. In addition, the mechanical properties are coupled with thermal phenomena and accumulated plastic strains. The adopted nonlocal and viscoplastic approaches enhance numerical efficiency and provide the possibility to simulate localization phenomena. The model is validated against experimental data from laboratory tests conducted on Callovo-Oxfordian (COx) claystone samples that are initially unsaturated and under suction. The tests include a thermal phase where the COx specimens are subjected to different temperature increases. A good agreement with experimental data is obtained. In addition, parametric analyses are carried out to investigate the influence of the hydraulic boundary conditions (B.C.) and post-failure behavior models on the THM behavior evolution. It is shown that different drainage conditions affect the thermally induced pore pressures that, in turn, influence the onset of softening. The constitutive model presented constitutes a promising approach for simulating the most important features of the THM behavior of clay rocks. It is a tool with a high potential for application to several relevant case studies, such as thermal fracturing analysis of nuclear waste disposal systems.
基金supported by the National Key R&D Program of China(No.2023YFA1507902)the Science and Technology Bureau of Dalian City(No.2021RT04)+3 种基金the Shaanxi Provincial Science and Technology Department(Nos.2024JC-YBQN-0100 and QCYRCXM-2023-079)the Youth innovation team project of Shaanxi Province Education Department(No.23JP199)the Science and Technology Plan Project of Yulin Government(No.2023-CXY-137)the Initial Scientific Research Fund of High Level Talents in Yulin University(No.2023GK44).
文摘Green and atom-economic depolymerization of lignin remains a great challenge due toits complex non-repetitive structure and the inert property for chemo-digestion. A redoxneutrallignin depolymerization system without the use of extra oxidant and/or reductantover a Co-NC catalyst has been developed in this work, providing the first non-noble metalheterogeneous catalytic system for redox-neutral valorization of lignin. Mechanistic studiesbased on control reactions and deuterium labeling experiments suggest that the reactionproceeds via ametal-catalyzed dehydrogenation of C_(α)-OH to afford a carbonyl intermediate,followed by C_(β)-O bond cleavage (via hydrogenolysis) to afford monophenols and aromaticketone products. The hydrogen used for the cleavage of the C_(β)-O bond originates from thealcoholmoiety in the substrate, and the cascade dehydrogenation and hydrogenolysis stepsare highly coupled, rendering it an efficient and atom-economic process.
文摘The effect of prenatal exposure to ambient particulate matter(PM)on birth weight varies considerably across studies,and the findings remain inconclusive.In this study,we conducted a meta-analysis to assess the associations between exposure to PM_(2.5) and PM10 and birth weight.A total of 74 studies were identified through searches in Web of Science,PubMed,Embase,and Ovid Medline,as well as manual searches,up to October 2024.We found that for each 10μg/m^(3) increase in PM_(2.5),the risk of low birth weight(LBW)increased significantly during the entire pregnancy(odds ratio[OR]=2.41,95%confidence interval[CI]:1.99–2.91)and in all trimesters.Similarly,for every 10μg/m^(3) increase in PM10 concentration,the risk of LBW increased significantly during the entire pregnancy(OR=1.46,95%CI:1.16–1.84).Subgroup analysis by maternal age for PM_(2.5) showed that mothers aged 30 and above had a significantly higher risk of LBW(OR=3.69,95%CI:2.81–4.84),compared with those under 30.In conclusion,maternal exposure to PM_(2.5) and PM_(10) is associated with an increased risk of LBW across all trimesters.Additionally,mothers aged 30 and above are at a higher risk of LBW,compared with younger mothers.Further research is needed to clarify the biological mechanisms by which PM pollution may contribute to LBW.
基金supported by the National Natural Science Foundation of China(Grant Nos.52279118 and U21A20159)Sub-project of National Key Research and Development(Grant No.2023YFC3007403).
文摘The seepage of groundwater and the strain-softening of rock mass in a submarine tunnel expand the plastic region of rock,thereby affecting its overall stability.It is therefore essential to study the stress and strain fields in the rocks surrounding the submarine tunnel by considering the coupled effect of strainsoftening and seepage.However,the evolution equation for the hydro-mechanical parameters in the existing fully coupled solution is a uniform equation that is unable to reproduce the characteristics of rock mass in practice.In this study,an updated numerical procedure for the submarine tunnel is derived by coupling strain-softening and seepage effect based on the experimental results.According to the hydro-mechanical coupling theory,the hydro-mechanical parameters such as elastic modulus,Poisson's ratio,Biot's coefficient and permeability coefficient of rocks are characterized by the fitting equations derived from the experimental data.Then,the updated numerical procedure is deduced with the governing equations,boundary conditions,seepage equations and fitting equations.The updated numerical procedure is verified accurately compared with the previous analytical solution.By utilizing the updated numerical procedure,the characteristics of stress field and the influences of initial pore water pressure,Biot's coefficient,and permeability coefficient on the stress,displacement and water-inflow of the surrounding rocks are discussed.Regardless of the variations in hydro-mechanical parameters,the stress distribution has a similar trend.The initial permeability coefficient exerts the most significant influence on the stress field.With the increases in initial pore water pressure and Biot's coefficient,the plastic region expands,and the water-inflow and displacement increase accordingly.Given the fact that the stability of the tunnel is more sensitive to the seepage force controlled by the hydraulic parameters,it is suggested to dewater the ground above the submarine tunnel to control the initial pore water pressure.
基金supported by the National Key R&D Program of China(No.2023YFA1507902)the National Natural Science Foundation of China(Nos.21721004 and 21878288)+1 种基金the science and technology bureau of Dalian city(No.2021RT04)the Strategic Priority Research Program of the Chinese Academy of Sciences(No.XDB17020100).
文摘N-participated lignin depolymerization is of great importance for the transformation of waste lignin into value-added chemicals.The vast majority of developed strategies employ organic amines as nitrogen source,and considerablemethods rely on excessive use of strong base,which suffers severe environmental issues.Herein,benzonitrile derivatives are synthesized from oxidized ligninβ-O-4 model compounds in the presence of solid nitrogen source(NH_(4))_(2)CO_(3)under mild,base-free conditions over commercially available copper catalyst.Mechanism studies suggest the transformation undergoes a one-pot,highly coupled cascade reaction path involving oxidative C-C bond cleavage and in-situ formation of C≡N bond.Of which,Cu(OAc)2 catalyzes the transfer of hydrogen from C_(β)(C_(β)-H)to C_(α),leading to the cleavage of C_(α)-C_(β)bonds to offer benzaldehyde derivative,this intermediate then reacts in-situ with(NH_(4))_(2)CO_(3)to afford the targeted aromatic nitrile product.Tetrabutylammonium iodide(TBAI),acting as a promoter,plays a key role in breaking the C_(α)-C_(β)bonds to form the intermediate benzaldehyde derivative.With this protocol,the feasibility of the production of value-added syringonitrile from birchwood lignin has been demonstrated.This transformation provides a sustainable approach to benzonitrile chemicals from renewable source of lignin.
基金funded by the National Key Research and Devel-opment Program of China(2018YFE0104200)the National Natural Science Foundation of China(52175274,82172065,and 51875310)+1 种基金the Tsinghua-Toyota Joint Research Fund,the Tsinghua Precision Medicine Foundationthe Cross-Strait Tsinghua Research Insti-tute Fund.
文摘Biodegradable magnesium(Mg)alloys exhibit excellent biocompatibility,adequate mechanical properties,and osteogenic effect.They can contribute to complete recovery of damaged tissues without concerns about a second surgery and have achieved clinical applications in orthopedic and cardiovascular fields.Porous scaffolds can provide functions such as bone integration and adjustable mechanical properties,thus widely used for bone repair.Additive manufacturing(AM)offers the advantages of design freedom and high precision,enabling the reliable production of porous scaffolds with customized structures.The combination of biodegradable Mg alloys,porous scaffolds,and AM processes has created tremendous opportunities for the precision treatment of bone defects.This article reviews the current development in the additive manufacturing process and design of Mg alloy biodegradable orthopedic implants,fo-cusing on chemical compositions,structural design,surface treatment,and their effects on mechanical properties,degradation behavior,and biocompatibility.Finally,the future perspective of porous Mg alloy biodegradable orthopedic implants is proposed.
基金funded by the National Key Research and Development Program of China (2018YFE0104200)National Natural Science Foundation of China (51875310, 52175274, 82172065)Tsinghua Precision Medicine Foundation
文摘Laser powder bed fusion(L-PBF)has been employed to additively manufacture WE43 magnesium(Mg)alloy biodegradable implants,but WE43 L-PBF samples exhibit excessively rapid corrosion.In this work,dense WE43 L-PBF samples were built with the relativity density reaching 99.9%.High temperature oxidation was performed on the L-PBF samples in circulating air via various heating temperatures and holding durations.The oxidation and diffusion at the elevated temperature generated a gradient structure composed of an oxide layer at the surface,a transition layer in the middle and the matrix.The oxide layer consisted of rare earth(RE)oxides,and became dense and thick with increasing the holding duration.The matrix was composed ofα-Mg,RE oxides and Mg_(24)RE_(5) precipitates.The precipitates almost disappeared in the transition layer.Enhanced passivation effect was observed in the samples treated by a suitable high temperature oxidation.The original L-PBF samples lost 40%weight after 3-day immersion in Hank’s solution,and broke into fragments after 7-day immersion.The casted and solution treated samples lost roughly half of the weight after 28-day immersion.The high temperature oxidation samples,which were heated at 525℃ for 8 h,kept the structural integrity,and lost only 6.88%weight after 28-day immersion.The substantially improved corrosion resistance was contributed to the gradient structure at the surface.On one hand,the outmost dense layer of RE oxides isolated the corrosive medium;on the other hand,the transition layer considerably inhibited the corrosion owing to the lack of precipitates.Overall,high temperature oxidation provides an efficient,economic and safe approach to inhibit the corrosion of WE43 L-PBF samples,and has promising prospects for future clinical applications.
基金National Key Research and Development Program of China(No.2018YFE0104200)National Natural Science Foundation of China(Nos.52175274,82172065,51875310)Tsinghua Precision Medicine Foundation and Tsinghua-Toyota Joint Research Fund.
文摘Laser powder bed fusion(L-PBF)has been used to fabricate biodegradable Mg implants of WE43 alloy,but the degradation is too fast compared with the term bone reconstruction.Previous studies show that high temperature oxidation(HTO)can successfully inhibit the degradation of WE43 alloy.In this work,the influence of HTO on L-PBF samples of WE43 alloy was investigated regarding tensile,compressive,and abrasive resistance,as well as in vitro cytotoxicity,cell proliferation,hemolysis,and osteogenesis.Compared with the as-built L-PBF samples,HTO increased grain size and grain texture,stabilized and coarsened precipitates,and caused discontinuous static recrystallization in the matrix.The oxide layer at the surface of the HTO samples improved surface roughness,hydrophilia,hardness,and abrasive resis-tance.The tensile strength decreased slightly from 292 to 265 MPa,while the elongation substantially increased from 10.97%to 16.58%after HTO.The in vitro cell viability,cell proliferation,hemolysis,and osteogenic effect were considerably enhanced due to the improvement of surface quality and the initial inhibition of excessive Mg^(2+)releasement.Overall,HTO is of great benefit to the surface performance,ductility,and biocompatibility of WE43 alloy fabricated by L-PBF for biodegradable applications.
基金supported by the National Key Research and Development Program of China(Nos.2022YFA1503801,2021YFA1600800)the Photon Science Center for Carbon Neutrality of Chinese Academy of Sciences+2 种基金Shanghai Science and Technology Development Funds(Nos.22YF1454500,23ZR1471400)the CAS Project for Young Scientists in Basic Research(No.YSBR-022)the National Natural Science Foundation of China(No.12305375)。
文摘A Johann-type X-ray spectrometer was successfully developed at the hard X-ray branch(in-vacuum undulator with a 24-mm periodic length)of the energy material beamline(E-line)at the Shanghai Synchrotron Radiation Facility(SSRF).This spectrometer was utilized to implement X-ray emission spectroscopy(XES),high-energy resolution fluorescence-detected X-ray absorption spectroscopy(HERFD-XAS),and resonant inelastic X-ray scattering.Seven spherically bent crystals were positioned on the respective vertical 500-mm-diameter Rowland circles,adopting an area detector to increase the solid angle to 1.75%of 4πsr,facilitating the study of low-concentrate systems under complex reaction conditions.Operated under the atmosphere pressure,the spectrometer covers the energy region from 3.5 to 18 keV,with the Bragg angle ranging from 73°to 86°during vertical scanning.It offers a promised energy resolution of sub-eV(XES)and super-eV(HERFD-XAS).Generally,these comprehensive core-level spectroscopy methods based on hard X-rays at the E-line with an extremely high photon flux can meet the crucial requirements of a green energy strategy.Moreover,they provide substantial support for scientific advances in fundamental research.
基金supported financially by the National Natural Science Foundation for Distinguished Young Scholars(No.81725021)the National Natural Science Foundation of China(Nos.82003633 and 82104043)the National Natural Science Foundation of Hubei Province(No.2023AFB791)。
文摘Monosescinol A(1),the first example of sesquiterpene–polycyclic polyprenylated acylphloroglucinol(PPAP)adduct,which represented a new subclass of PPAP-type natural products,along with two new congeners with normal spiro 6/6/5 tricyclic architecture,were isolated from Hypericum longistylum.Monosescinol A possessed an unprecedented 6/5/5/6/6 pentacyclic carbon skeleton that might be assembled from the 6/6/5 carbon skeleton,via the splitting decomposition of C-3/C-14,and the attack from the C-3 in the PPAP core to C-28 in sesquiterpene section.In addition,we have firstly confirmed that 24R configuration was existed in sec–Bu containing PPAPs by single crystal diffraction data analysis of monosescinol B(2),that might provide an enlightenment in the configurational determination of sec–Bu containing PPAPs.Significantly,further pharmacological research has found that compound 1 exhibited remarkable pharmacological effects against acute myeloid leukemia(AML)cell lines,with direct inhibition of mitochondrial complex V and an increase in mitochondrial membrane potential,and led to an induction of oxidative stress,endogenous inflammation,and apoptosis of AML cells.
