TiFe alloys are AB-based hydrogen storage materials with unique characteristics and a wide range of applications.However,the presence of impurity gases(such as O_(2),CO,CO_(2),and CH4)has a considerable impact on the ...TiFe alloys are AB-based hydrogen storage materials with unique characteristics and a wide range of applications.However,the presence of impurity gases(such as O_(2),CO,CO_(2),and CH4)has a considerable impact on the hydrogen storage capacity and kinetics of TiFe alloys,drastically limiting their practical application in hydrogen storage.Consequently,in this study,we investigated the hydrogen absorption kinetics and cycling performance of the TiFe_(0.9) alloy in the presence of common impurity gases(including CH4,CO,CO_(2),and O_(2))and determined the corresponding poisoning mechanisms.Specifically,we found that CH4 did not react with the alloy but acted through physical coverage.In contrast,CO and CO_(2) occupy the active sites for H_(2),significantly impeding the dissociation and absorption of H_(2).In addition,O_(2) reacts directly with the alloy to form a passivating layer that prevents hydrogen absorption.These findings were fur-ther corroborated by in situ Fourier transform infrared spectrometry(FTIR)and density functional theory(DFT).The relationship between the adsorption energies of the impurity gases and hydrogen obtained through DFT calculations complements the experimental results.Un-derstanding these poisoning behaviors is crucial for designing Ti-based high-entropy hydrogen storage alloy alloys with enhanced resist-ance to poisoning.展开更多
Although MgH_(2)is widely deemed to be the most promising solid-state hydrogen storage materials for the medium-high temperature fuelcell applications expected in the near future,the high-temperature desorption and sl...Although MgH_(2)is widely deemed to be the most promising solid-state hydrogen storage materials for the medium-high temperature fuelcell applications expected in the near future,the high-temperature desorption and sluggish hydrogen absorption/desorption kinetics are the major challenges for its applications.Herein,reduced graphene oxide/patronite nanoparticle composite(rGO@VS_(4))is successfully synthesized using an ionic liquid(IL)-assisted hydrothermal method,and superior catalytic effects originated from the rGO@VS_(4)composite precursor towards the hydrogen storage reaction of MgH_(2)are systematically investigated.The VS_(4)reacts with MgH_(2)leads to the in-situ formed and uniformly scattered of metallic V and MgS during both ball-milling and the initial hydrogen desorption,and the synergic catalytic effect of metallic V and MgS facilitates the improved hydrogen desorption of MgH_(2).The MgH_(2)-15 wt%rGO@VS_(4)composite starts releasing hydrogen at 180℃and peaks at 220℃,which is 145℃and 128℃lower than that of the Pristine MgH_(2),respectively.The energy required for H_(2)desorption from MgH_(2)is decreased to 63.8 kJ mol^(-1),58.9 kJ mol^(-1)lower than that of the Pristine MgH_(2).Furthermore,the MgH_(2)-15 wt%rGO@VS_(4)composite shows excellent cycling stability,of which reversible hydrogen capacity can stabilize at about 5.9 wt%with capacity retention of 98.2%at 300℃for 100 cycles.This study provides a deeper insight into metallic V and MgS to enhance the hydrogen desorption of solid-state hydrogen storage materials and also offers a perspective for the construction of high-activity catalysts for solid-state hydrogen storage materials.展开更多
The role of catalysts in enhancing the hydrogen storage kinetics of the Mg/MgH_(2)system is pivotal.However,the exploration of efficient catalysts and the underlying principles of their design remain both a prominent ...The role of catalysts in enhancing the hydrogen storage kinetics of the Mg/MgH_(2)system is pivotal.However,the exploration of efficient catalysts and the underlying principles of their design remain both a prominent focus and a significant challenge in current research.In this study,we present a bimetallic oxide of Bi_(2)Ti_(2)O_(7)hollow sphere as a highly effective catalyst for MgH_(2).As a result,the Bi_(2)Ti_(2)O_(7)-catalyzed Mg/MgH_(2)system lowers the hydrogen desorption initiation temperature to 194.3℃,reduces the peak desorption temperature to 245.6℃,decreases the dehydrogenation activation energy to 82.14 kJ·mol^(−1),and can absorb 5.4 wt.%of hydrogen within 60 s at 200℃,demonstrating outstanding hydrogen ab/desorption kinetics,compared to pure MgH_(2).Additionally,it can maintain a high hydrogen capacity of 5.2 wt.%,even after 50 dehydrogenation cycles,showing good cycle stability.The characterization results show that the high-valent Bi and Ti in Bi_(2)Ti_(2)O_(7)are reduced to their low-valent or even zero-valent metallic states during the dehydrogenation and hydrogenation process,thus establishing an in-situ multivalent and multi-element catalytic environment.Density functional theory calculations further reveal that the synergistic effects between Bi and Ti in the Bi-Ti mixed oxide facilitate the cleavage of Mg-H bonds and lower the kinetic barrier for the dissociation of hydrogen molecules,thereby substantially enhancing the kinetics of the Mg/MgH_(2)system.This study presents a strategic method for developing efficient catalysts for hydrogen storage materials by harnessing the synergistic effects of metal elements.展开更多
Owing to anionic redox,cathode materials containing layered Li-rich Mn-based oxides(LLOs)are promising for the development of next-generation lithium-ion batteries(LIBs)with a large energy density(~500–600 Wh·kg...Owing to anionic redox,cathode materials containing layered Li-rich Mn-based oxides(LLOs)are promising for the development of next-generation lithium-ion batteries(LIBs)with a large energy density(~500–600 Wh·kg^(−1)).However,these LLOs are easily degraded during cycling,which limits their lifespan.So far,the degradation mechanism is still under debate.Herein,LLOs are post-treated through implantation with energetic Ti ion flux(Ti-LLO),which modifies the structure of LLOs both at the surface and within the bulk.Unlike the dominant R3m phase(73.24%)observed in LLOs,the phase structure of Ti-LLO is altered,with Li-rich C2/m accounting for 67.72%in the bulk,alongside the formation of a thin(approximately 2 nm),uniform,and continuous Li-Ti-O spinel layer at the surface.Apart from phase structure changes,chemical valence states of transition metals and O,as well as their evolution,are analyzed and compared to charge transport kinetics to elucidate their contributions to the enhanced discharge capacity in Ti-LLOs.Besides,the role of the Li-Ti-O spinel layer at the surface in providing anticorrosion protection at the interface of LLOs/electrolyte during cycling is evaluated.As a result,we demonstrate that a superhigh discharge capacity(335.3 mAh·g^(−1))at 0.1 C can be achieved,along with prolonged cycling stability(showing capacity retention of approximately 80%after 500 cycles at 1 C)through these modifications.Moreover,we confirmed the universality of the strategy by implanting other ions,which offers practical strategies for achieving high performance in LLO cathode materials through thermodynamics and kinetics pathways.展开更多
Human induced pluripotent stem （iPS） cells are similar to embryonic stem （ES） cells, and can proliferate intensively and differentiate into a variety of cell types. However, the hepatic differentiation of human iP...Human induced pluripotent stem （iPS） cells are similar to embryonic stem （ES） cells, and can proliferate intensively and differentiate into a variety of cell types. However, the hepatic differentiation of human iPS cells has not yet been reported. In this report, human iPS cells were induced to differentiate into hepatic cells by a stepwise protocol. The expression of liver cell markers and liver-related functions of the human iPS cell-derived cells were monitored and compared with that of differentiated human ES cells and primary human hepatocytes. Approximately 60% of the differentiated human iPS cells at day 7 expressed hepatic markers alpha fetoprotein and Alb. The differentiated cells at day 21 exhibited liver cell functions including albumin Asecretion, glycogen synthesis, urea production and inducible cytochrome P450 activity. The expression of hepatic markers and fiver-related functions of the iPS cellderived hepatic ceils were comparable to that of the human ES cell-derived hepatic cells. These results show that human iPS cells, which are similar to human ES cells, can be efficiently induced to differentiate into hepatocyte-like cells.展开更多
Exploring highly active but inexpensive electrocatalysts for the hydrogen evolution reaction(HER)is of critical importance for hydrogen production from electrochemical water splitting.Herein,we report a multicomponent...Exploring highly active but inexpensive electrocatalysts for the hydrogen evolution reaction(HER)is of critical importance for hydrogen production from electrochemical water splitting.Herein,we report a multicomponent catalyst with exceptional activity and durability for HER,in which cobalt nanoparticles were in-situ confined inside bamboo-like carbon nanotubes(CNTs)while ultralow ruthenium loading(~2.6μg per electrode area~cm^(−2))is uniformly deposited on their exterior walls(Co@CNTsǀRu).The atomic-scale structural investigations and theoretical calculations indicate that the confined inner Co and loaded outer Ru would induce charge redistribution and a synergistic electron coupling,not only optimizing the adsorption energy of H intermediates(ΔGH*)but also facilitating the electron/mass transfer.The as-developed Co@CNTsǀRu composite catalyst requires overpotentials of only 10,32,and 63 mV to afford a current density of 10 mA cm^(−2) in alkaline,acidic and neutral media,respectively,representing top-level catalytic activity among all reported HER catalysts.The current work may open a new insight into the rational design of carbon-supported metal catalysts for practical applications.展开更多
Background:Xiaoqinglong decoction(XQLD)is a classic Chinese medicinal formula that is widely used to treat allergic asthma.Recently,the use of XQLD to treat allergic asthma has inspired research to determine its mecha...Background:Xiaoqinglong decoction(XQLD)is a classic Chinese medicinal formula that is widely used to treat allergic asthma.Recently,the use of XQLD to treat allergic asthma has inspired research to determine its mechanism of action.Because dendritic cells(DCs)and the T helper 1(Th1)/Th2 cytokine balance play important roles in allergic asthma,the present work aimed to assess how these immune system components are affected by XQLD.Methods:Thirty-six female BALB/C mice were randomly divided into three groups:an ovalbumin-based allergic asthma model group,a XQLD treatment group,and a control group.Histology was performed with haematoxylin and eosin staining and immunohistochemical staining.Bronchoalveolar lavage fluid and blood were collected from the animals and used to analyze the composition of inflammatory cells and expression levels of the cytokines interleukin(IL)-5 and IL-13.The thymic stromal lymphopoietin(TSLP)protein expression was assessed by western blot analysis,and the Gata3 and Tbx21 mRNA levels were assessed by polymerase chain reaction.Results:Compared with the OVA group,the levels of TSLP expression,IL-5,IL-13,and immunoglobulin E in the XQLD group were lower(all P<.01).The level of IL-4-expressing cells(Th2 cells)was lower(P=.0013),and the percentage of IFN-g-expressing cells(Th1 cells)was higher in the XQLD group compared with those in the OVA group(P=.0065).In addition,XQLD increased the expression of Tbx21 mRNA and decreased the expression of Gata3 mRNA in the lungs compared with the OVA group(both P<.01).Conclusion:These findings suggest that XQLD may ameliorate the course of allergic asthma by regulating the Gata3/Tbx21 balance and inhibiting TSLP expression,changes which are indicative of an altered Th1/Th2 balance.Thus,the clinical effectiveness of XQLD in treating allergic asthma may be due to its regulation of Th1/Th2 balance.展开更多
The construction of stable cathode electrolyte interphase(CEI)is the key to improve the NCM811 particle structure and interfacial stability via electrolyte engineering.In He’s work,lithium hexamethyldisilazide(LiHMDS...The construction of stable cathode electrolyte interphase(CEI)is the key to improve the NCM811 particle structure and interfacial stability via electrolyte engineering.In He’s work,lithium hexamethyldisilazide(LiHMDS)as the electrolyte additive is proposed to facilitate the generation of stable CEI on NCM811 cathode surface and eliminate H_(2)O and HF in the electrolyte at the same time,which boosts the cycling performance of Li||NCM811 battery up to 1000 or 500 cycles with 4.5 V cut-off voltage at 25 or 60℃.展开更多
Multifunctional composite catalyst for carbonyl sulfide hydrolysis under moderate temperature was prepared by impregnation method. The hydrolysis and deoxidization ability of the prepared catalyst was investigated in ...Multifunctional composite catalyst for carbonyl sulfide hydrolysis under moderate temperature was prepared by impregnation method. The hydrolysis and deoxidization ability of the prepared catalyst was investigated in a fixed bed reactor. It was found that deoxidization ability of the prepared catalyst was raised by the increase of the content of potassium loading catalyst and reaction temperature. And the concentration of H2S had no effect on deoxidization while COS improved the deoxidization ratio. And deoxidization rates were nearly scaled up with concentration of H2. The hydrolysis ability was decreased by the decrease of the surface basicity.展开更多
Electrocatalytic 5-hydroxymethylfurfural oxidation reaction(HMFOR)provides a promising strategy to convert biomass derivative to highvalue-added chemicals.Herein,a cascade strategy is proposed to construct Pd-NiCo_(2)...Electrocatalytic 5-hydroxymethylfurfural oxidation reaction(HMFOR)provides a promising strategy to convert biomass derivative to highvalue-added chemicals.Herein,a cascade strategy is proposed to construct Pd-NiCo_(2)O_(4)electrocatalyst by Pd loading on Ni-doped Co3O4 and for highly active and stable synergistic HMF oxidation.An elevated current density of 800 mA cm^(-2)can be achieved at 1.5 V,and both Faradaic efficiency and yield of 2,5-furandicarboxylic acid remained close to 100%over 10 consecutive electrolysis.Experimental and theoretical results unveil that the introduction of Pd atoms can modulate the local electronic structure of Ni/Co,which not only balances the competitive adsorption of HMF and OH-species,but also promote the active Ni^(3+)species formation,inducing high indirect oxidation activity.We have also discovered that Ni incorporation facilitates the Co2+pre-oxidation and electrophilic OH*generation to contribute direct oxidation process.This work provides a new approach to design advanced electrocatalyst for biomass upgrading.展开更多
We establish a general mapping from one-dimensional non-Hermitian mosaic models to their non-mosaic counterparts.This mapping can give rise to mobility edges and even Lyapunov exponents in the mosaic models if critica...We establish a general mapping from one-dimensional non-Hermitian mosaic models to their non-mosaic counterparts.This mapping can give rise to mobility edges and even Lyapunov exponents in the mosaic models if critical points of localization or Lyapunov exponents of localized states in the corresponding non-mosaic models have already been analytically solved.To demonstrate the validity of this mapping,we apply it to two non-Hermitian localization models:an Aubry-Andre-like model with nonreciprocal hopping and complex quasiperiodic potentials,and the Ganeshan-Pixley-Das Sarma model with nonreciprocal hopping.We successfully obtain the mobility edges and Lyapunov exponents in their mosaic models.This general mapping may catalyze further studies on mobility edges,Lyapunov exponents,and other significant quantities pertaining to localization in non-Hermitian mosaic models.展开更多
Rechargeable lithium metal batteries(LMBs)meet the demands of high-energy applications in electric vehicles and truck transportation[1-4].Yet,the low coulombic efficiency(CE)hinders the widespread application of Li an...Rechargeable lithium metal batteries(LMBs)meet the demands of high-energy applications in electric vehicles and truck transportation[1-4].Yet,the low coulombic efficiency(CE)hinders the widespread application of Li anode,which is closely related to the electrolytes[5-7].The CE of traditional electrolytes for Li anodes is closely related to the speciation of the plated Li during cycling,where fluorinated solvents with weakly solvated Li+usually exhibit larger Li deposition particles with higher CE[8,9].But the relationship between the morphological difference and CE in different electrolytes is less studied[10,11].There are three relationships between the deposition kinetics of interface Li and the cycling of the battery,no correlation,positive correlation[12,13],and negative correlation[14,15]have been reported on active Li anodes,which neglects the reactivity of Li metal in kinetics.Solid electrolyte interphase(SEl)was formed by the electrolytes reacting with Li,and Li deposition can occur on the Li/SEl interface or the fresh Li/electrolyte interface[16,17].Each pathway has different deposition kinetics.Therefore,in order to understand the relationship between electrolyte kinetics and lithium deposition morphology,it is important to solve the kinetics of the two ways in the electrolyte.展开更多
Epidermal growth factor receptor inhibitors have shown promise in the treatment of colorectal cancers. However, activating KRAS mutations cause primary resistance to these agents and contribute to cancer progression. ...Epidermal growth factor receptor inhibitors have shown promise in the treatment of colorectal cancers. However, activating KRAS mutations cause primary resistance to these agents and contribute to cancer progression. Downstream signaling of oncogenic KRAS induces activation of HIF-1α and HIF-2α which in turn activate genes that promote cell proliferation, obstruct cell death, and induce angiogenesis and metabolic adaptation. We will discuss clinical trial results with EGFR inhibitors, mechanism of resistance mediated by oncogenic KRAS, and strategies under clinical development to overcome KRAS-mediated resistance.展开更多
Nanocomposite membranes containing poly（m-phenylene isophthalamide）（PMIA） and organically modified montmorillonite（OMMT） were prepared by a combination of solution dispersion and wet-phase inversion methods, and...Nanocomposite membranes containing poly（m-phenylene isophthalamide）（PMIA） and organically modified montmorillonite（OMMT） were prepared by a combination of solution dispersion and wet-phase inversion methods, and the effects of OMMT addition on the properties and performance of fabricated nanofiltration membranes were investigated. The membranes were characterized by contact angle measurements, scanning electron microscopy（SEM）, atomic force microscopy（AFM）, thermogravimetric analysis, and zeta potential.The performance of the membranes was elucidated by the removal of perfluorooctane sulfonate（PFOS） at neutral p H. Increasing OMMT concentration improved the thermal stability and hydrophilicity of the membranes. The permeation and rejection of PFOS were significantly improved. The performance of fabricated nanofiltration membranes in removal of PFOS varied depending on the solute and membrane properties as well as solution conditions. Finally,a comparison between fabricated membranes and a commercial NF membrane（ESNA1-K1,Hydecanme） proved that the OMMT addition is a convenient procedure for producing nanocomposite membranes with superior properties and performance.展开更多
Erythropoiesis is a finely regulated and complex process that involves multiple transformations from hematopoietic stem cells to mature red blood cells at hematopoietic sites from the embryonic to adult stages.Investi...Erythropoiesis is a finely regulated and complex process that involves multiple transformations from hematopoietic stem cells to mature red blood cells at hematopoietic sites from the embryonic to adult stages.Investigations into its molecular mechanisms have generated a wealth of expression data,including bulk and single-cell RNA sequencing data.A comprehensively integrated and well-curated erythropoiesis-specific database will greatly facilitate the mining of gene expression data and enable large-scale research of erythropoiesis and erythroid-related diseases.Here,we present EryDB,an open-access and comprehensive database dedicated to the collection,integration,analysis,and visualization of transcriptomic data for erythropoiesis and erythroid-related diseases.Currently,the database includes expertly curated quality-assured data of 3803 samples and 1,187,119 single cells derived from 107 public studies of three species(Homo sapiens,Mus musculus,and Danio rerio),nine tissue types,and five diseases.EryDB provides users with the ability to not only browse the molecular features of erythropoiesis between tissues and species,but also perform computational analyses of single-cell and bulk RNA sequencing data,thus serving as a convenient platform for customized queries and analyses.EryDB v1.0 is freely accessible at https://ngdc.cncb.ac.cn/EryDB/home.展开更多
Knowledge of raindrop size distribution(RSD)is essential for understanding microphysical processes occurring within cloud and precipitation systems,as well as for enhancing the capabilities of numerical models and rad...Knowledge of raindrop size distribution(RSD)is essential for understanding microphysical processes occurring within cloud and precipitation systems,as well as for enhancing the capabilities of numerical models and radar-based quantitative precipitation estimation(QPE).However,observation and study of RSD,especially its temporal and spatial variability,remain quite limited in specific regions.One such region is Southeast China.In this paper,four years of disdrometer data from a south coastal plain site(CPS)and a north hilly inland site(HIS)in the Fujian Province of Southeast China are analyzed and compared to elucidate the characteristics and discrepancies of RSD between these two distinct climatological sites.On this basis,empirical relations between the parameters of Gamma distribution and between radar reflectivity factor(Z)and rain rate(R)are proposed.The results are summarized as follows.(1)In the cases of light to moderate rains,HIS exhibits a higher(lower)concentration of small-size(midsize and large)raindrops with diameters of D<1 mm(1≤3 and D≥3 mm),compared to CPS.Conversely,as the rain intensity increases,the raindrop concentrations across all size categories at CPS gradually exceed those at HIS.(2)RSDs at both sites broaden and exhibit elevated concentrations across most diameter categories as the rain rate increases.(3)For rainfalls with rain rates below 5 mm h^(-1),collision and coalescence dominate,resulting in unimodal rain spectra at both sites;whereas for stronger rainfalls,breakup intensifies,leading to the development of bimodal rain spectra.(4)HIS experiences more stratiform rains but fewer,weaker convective rains than CPS.Stratiform RSD at HIS possesses more small and large raindrops but fewer midsize raindrops compared to CPS,whereas convective RSD at CPS possesses higher concentrations across all diameter categories.(5)Accordingly,specific Z–R relations at these two sites are proposed and validated for two real cases,demonstrating that the accuracy of radar QPE is effectively improved based on the proposed Z–R relations.展开更多
基金supported by the National Key Research&Development Program of China(No.2022YFB4004301)the National Natural Science Foundation of China(Nos.52201274 and 52307250)the Shaanxi Province key research and development plan,China(No.2024CY2-GJHX-53).
文摘TiFe alloys are AB-based hydrogen storage materials with unique characteristics and a wide range of applications.However,the presence of impurity gases(such as O_(2),CO,CO_(2),and CH4)has a considerable impact on the hydrogen storage capacity and kinetics of TiFe alloys,drastically limiting their practical application in hydrogen storage.Consequently,in this study,we investigated the hydrogen absorption kinetics and cycling performance of the TiFe_(0.9) alloy in the presence of common impurity gases(including CH4,CO,CO_(2),and O_(2))and determined the corresponding poisoning mechanisms.Specifically,we found that CH4 did not react with the alloy but acted through physical coverage.In contrast,CO and CO_(2) occupy the active sites for H_(2),significantly impeding the dissociation and absorption of H_(2).In addition,O_(2) reacts directly with the alloy to form a passivating layer that prevents hydrogen absorption.These findings were fur-ther corroborated by in situ Fourier transform infrared spectrometry(FTIR)and density functional theory(DFT).The relationship between the adsorption energies of the impurity gases and hydrogen obtained through DFT calculations complements the experimental results.Un-derstanding these poisoning behaviors is crucial for designing Ti-based high-entropy hydrogen storage alloy alloys with enhanced resist-ance to poisoning.
基金supported by the National Key Research and Development Program of China(2022YFB3803801)National Natural Science Foundation of China(Grant No.52201275,52301287,52307250)+1 种基金Two-chain integration key project of Shaanxi Province(Grant No.2021LLRH-09)Young Talent Fund of Association for Science and Technology in Shaanxi,China(No.20220456).
文摘Although MgH_(2)is widely deemed to be the most promising solid-state hydrogen storage materials for the medium-high temperature fuelcell applications expected in the near future,the high-temperature desorption and sluggish hydrogen absorption/desorption kinetics are the major challenges for its applications.Herein,reduced graphene oxide/patronite nanoparticle composite(rGO@VS_(4))is successfully synthesized using an ionic liquid(IL)-assisted hydrothermal method,and superior catalytic effects originated from the rGO@VS_(4)composite precursor towards the hydrogen storage reaction of MgH_(2)are systematically investigated.The VS_(4)reacts with MgH_(2)leads to the in-situ formed and uniformly scattered of metallic V and MgS during both ball-milling and the initial hydrogen desorption,and the synergic catalytic effect of metallic V and MgS facilitates the improved hydrogen desorption of MgH_(2).The MgH_(2)-15 wt%rGO@VS_(4)composite starts releasing hydrogen at 180℃and peaks at 220℃,which is 145℃and 128℃lower than that of the Pristine MgH_(2),respectively.The energy required for H_(2)desorption from MgH_(2)is decreased to 63.8 kJ mol^(-1),58.9 kJ mol^(-1)lower than that of the Pristine MgH_(2).Furthermore,the MgH_(2)-15 wt%rGO@VS_(4)composite shows excellent cycling stability,of which reversible hydrogen capacity can stabilize at about 5.9 wt%with capacity retention of 98.2%at 300℃for 100 cycles.This study provides a deeper insight into metallic V and MgS to enhance the hydrogen desorption of solid-state hydrogen storage materials and also offers a perspective for the construction of high-activity catalysts for solid-state hydrogen storage materials.
基金supported by the National Key Research and Development Program of China(No.2024YFB4007204,2022YFB4004301)the National Natural Science Founda-tion of China(Grant Nos.52477220,52301287,22005353)+2 种基金the Two-chain Integration Key Project of Shaanxi Province(2021LLRH-09)the Key Research and Development Program of Shaanxi Province(No.2024CY2-GJHX-44,2024CY2-GJHX-53,2024GX-ZDCYL-04-06)the Key Industrial Chain Technology Research Program of Xi’an city(23LL-RHZDZX0017).
文摘The role of catalysts in enhancing the hydrogen storage kinetics of the Mg/MgH_(2)system is pivotal.However,the exploration of efficient catalysts and the underlying principles of their design remain both a prominent focus and a significant challenge in current research.In this study,we present a bimetallic oxide of Bi_(2)Ti_(2)O_(7)hollow sphere as a highly effective catalyst for MgH_(2).As a result,the Bi_(2)Ti_(2)O_(7)-catalyzed Mg/MgH_(2)system lowers the hydrogen desorption initiation temperature to 194.3℃,reduces the peak desorption temperature to 245.6℃,decreases the dehydrogenation activation energy to 82.14 kJ·mol^(−1),and can absorb 5.4 wt.%of hydrogen within 60 s at 200℃,demonstrating outstanding hydrogen ab/desorption kinetics,compared to pure MgH_(2).Additionally,it can maintain a high hydrogen capacity of 5.2 wt.%,even after 50 dehydrogenation cycles,showing good cycle stability.The characterization results show that the high-valent Bi and Ti in Bi_(2)Ti_(2)O_(7)are reduced to their low-valent or even zero-valent metallic states during the dehydrogenation and hydrogenation process,thus establishing an in-situ multivalent and multi-element catalytic environment.Density functional theory calculations further reveal that the synergistic effects between Bi and Ti in the Bi-Ti mixed oxide facilitate the cleavage of Mg-H bonds and lower the kinetic barrier for the dissociation of hydrogen molecules,thereby substantially enhancing the kinetics of the Mg/MgH_(2)system.This study presents a strategic method for developing efficient catalysts for hydrogen storage materials by harnessing the synergistic effects of metal elements.
基金supported by the National Key Research and Development Program of China(2022YFB2502000)the National Natural Science Foundation of China(52201277,52207244,52207245)+1 种基金the Xi'an Young Talent Lifting Program(959202413060)the National Outstanding Youth Foundation of China(52125104).
文摘Owing to anionic redox,cathode materials containing layered Li-rich Mn-based oxides(LLOs)are promising for the development of next-generation lithium-ion batteries(LIBs)with a large energy density(~500–600 Wh·kg^(−1)).However,these LLOs are easily degraded during cycling,which limits their lifespan.So far,the degradation mechanism is still under debate.Herein,LLOs are post-treated through implantation with energetic Ti ion flux(Ti-LLO),which modifies the structure of LLOs both at the surface and within the bulk.Unlike the dominant R3m phase(73.24%)observed in LLOs,the phase structure of Ti-LLO is altered,with Li-rich C2/m accounting for 67.72%in the bulk,alongside the formation of a thin(approximately 2 nm),uniform,and continuous Li-Ti-O spinel layer at the surface.Apart from phase structure changes,chemical valence states of transition metals and O,as well as their evolution,are analyzed and compared to charge transport kinetics to elucidate their contributions to the enhanced discharge capacity in Ti-LLOs.Besides,the role of the Li-Ti-O spinel layer at the surface in providing anticorrosion protection at the interface of LLOs/electrolyte during cycling is evaluated.As a result,we demonstrate that a superhigh discharge capacity(335.3 mAh·g^(−1))at 0.1 C can be achieved,along with prolonged cycling stability(showing capacity retention of approximately 80%after 500 cycles at 1 C)through these modifications.Moreover,we confirmed the universality of the strategy by implanting other ions,which offers practical strategies for achieving high performance in LLO cathode materials through thermodynamics and kinetics pathways.
基金We thank Dr Zicai Liang and Huang Huang （Institute of Molecular Medicine, Peking University） for their kind help with BioTek Multi-Detection Microplate Reader and Yizhe Zhang for technical support on real-time PCR. We also thank Chengyan Wang, Pengbo Zhang, Pingping Hou, Haisong Liu, Chun Liu and other colleagues in our laboratory for technical assistance and advice in carrying out these experiments. This study was supported by a Bill ＆ Melinda Gates Foundation Grant （37871）, a Ministry of Education grant （705001）, the National Basic Research Program of China （973 program, 2009CB522502, 2009CB941200 and 2007CB947901）, National Natural Science Foundation of China for Creative Research Groups （30421004）, the Chinese Science and Technology Key Project （2008zx10002-014, 2008zx10002- 011 and 2009ZX 10004-403） and a 111 Project to Deng H.
文摘Human induced pluripotent stem （iPS） cells are similar to embryonic stem （ES） cells, and can proliferate intensively and differentiate into a variety of cell types. However, the hepatic differentiation of human iPS cells has not yet been reported. In this report, human iPS cells were induced to differentiate into hepatic cells by a stepwise protocol. The expression of liver cell markers and liver-related functions of the human iPS cell-derived cells were monitored and compared with that of differentiated human ES cells and primary human hepatocytes. Approximately 60% of the differentiated human iPS cells at day 7 expressed hepatic markers alpha fetoprotein and Alb. The differentiated cells at day 21 exhibited liver cell functions including albumin Asecretion, glycogen synthesis, urea production and inducible cytochrome P450 activity. The expression of hepatic markers and fiver-related functions of the iPS cellderived hepatic ceils were comparable to that of the human ES cell-derived hepatic cells. These results show that human iPS cells, which are similar to human ES cells, can be efficiently induced to differentiate into hepatocyte-like cells.
基金supported by“Shuguang Program”supported by Shanghai Education Development Foundation and Shanghai Municipal Education Commission Shaanxi Outstanding Youth Fund(2020JC-49)Youth Innovation Team of University in Shaanxi Province(20SG03)+2 种基金State Key Laboratory of New Textile Materials and Advanced Processing Technologies(No.FZ2021001)Guangdong Basic and Applied Basic Research Foundation(2021A1515110496)the Natural Science Basic Research Plan in Shaanxi Province of China(No.2022JQ-438).
文摘Exploring highly active but inexpensive electrocatalysts for the hydrogen evolution reaction(HER)is of critical importance for hydrogen production from electrochemical water splitting.Herein,we report a multicomponent catalyst with exceptional activity and durability for HER,in which cobalt nanoparticles were in-situ confined inside bamboo-like carbon nanotubes(CNTs)while ultralow ruthenium loading(~2.6μg per electrode area~cm^(−2))is uniformly deposited on their exterior walls(Co@CNTsǀRu).The atomic-scale structural investigations and theoretical calculations indicate that the confined inner Co and loaded outer Ru would induce charge redistribution and a synergistic electron coupling,not only optimizing the adsorption energy of H intermediates(ΔGH*)but also facilitating the electron/mass transfer.The as-developed Co@CNTsǀRu composite catalyst requires overpotentials of only 10,32,and 63 mV to afford a current density of 10 mA cm^(−2) in alkaline,acidic and neutral media,respectively,representing top-level catalytic activity among all reported HER catalysts.The current work may open a new insight into the rational design of carbon-supported metal catalysts for practical applications.
基金the National Natural Science Foundation of China(816015085).
文摘Background:Xiaoqinglong decoction(XQLD)is a classic Chinese medicinal formula that is widely used to treat allergic asthma.Recently,the use of XQLD to treat allergic asthma has inspired research to determine its mechanism of action.Because dendritic cells(DCs)and the T helper 1(Th1)/Th2 cytokine balance play important roles in allergic asthma,the present work aimed to assess how these immune system components are affected by XQLD.Methods:Thirty-six female BALB/C mice were randomly divided into three groups:an ovalbumin-based allergic asthma model group,a XQLD treatment group,and a control group.Histology was performed with haematoxylin and eosin staining and immunohistochemical staining.Bronchoalveolar lavage fluid and blood were collected from the animals and used to analyze the composition of inflammatory cells and expression levels of the cytokines interleukin(IL)-5 and IL-13.The thymic stromal lymphopoietin(TSLP)protein expression was assessed by western blot analysis,and the Gata3 and Tbx21 mRNA levels were assessed by polymerase chain reaction.Results:Compared with the OVA group,the levels of TSLP expression,IL-5,IL-13,and immunoglobulin E in the XQLD group were lower(all P<.01).The level of IL-4-expressing cells(Th2 cells)was lower(P=.0013),and the percentage of IFN-g-expressing cells(Th1 cells)was higher in the XQLD group compared with those in the OVA group(P=.0065).In addition,XQLD increased the expression of Tbx21 mRNA and decreased the expression of Gata3 mRNA in the lungs compared with the OVA group(both P<.01).Conclusion:These findings suggest that XQLD may ameliorate the course of allergic asthma by regulating the Gata3/Tbx21 balance and inhibiting TSLP expression,changes which are indicative of an altered Th1/Th2 balance.Thus,the clinical effectiveness of XQLD in treating allergic asthma may be due to its regulation of Th1/Th2 balance.
基金the support from the National Natural Science Foundation of China(Grant No.51971090 and U21A20311)。
文摘The construction of stable cathode electrolyte interphase(CEI)is the key to improve the NCM811 particle structure and interfacial stability via electrolyte engineering.In He’s work,lithium hexamethyldisilazide(LiHMDS)as the electrolyte additive is proposed to facilitate the generation of stable CEI on NCM811 cathode surface and eliminate H_(2)O and HF in the electrolyte at the same time,which boosts the cycling performance of Li||NCM811 battery up to 1000 or 500 cycles with 4.5 V cut-off voltage at 25 or 60℃.
文摘Multifunctional composite catalyst for carbonyl sulfide hydrolysis under moderate temperature was prepared by impregnation method. The hydrolysis and deoxidization ability of the prepared catalyst was investigated in a fixed bed reactor. It was found that deoxidization ability of the prepared catalyst was raised by the increase of the content of potassium loading catalyst and reaction temperature. And the concentration of H2S had no effect on deoxidization while COS improved the deoxidization ratio. And deoxidization rates were nearly scaled up with concentration of H2. The hydrolysis ability was decreased by the decrease of the surface basicity.
基金financially supported by Key Research and Development Projects of Sichuan Province (2023YFG0222)“Tianfu Emei” Science and Technology Innovation Leader Program in Sichuan Province (2021)+3 种基金University of Electronic Science and Technology of China Talent Start-up Funds (A1098 5310 2360 1208)the Youth Innovation Promotion Association of CAS (2020458)National Natural Science Foundation of China (21464015, 21472235, 52122212, 12274391, 223210001)Beijing Natural Science Foundation (IS23045)
文摘Electrocatalytic 5-hydroxymethylfurfural oxidation reaction(HMFOR)provides a promising strategy to convert biomass derivative to highvalue-added chemicals.Herein,a cascade strategy is proposed to construct Pd-NiCo_(2)O_(4)electrocatalyst by Pd loading on Ni-doped Co3O4 and for highly active and stable synergistic HMF oxidation.An elevated current density of 800 mA cm^(-2)can be achieved at 1.5 V,and both Faradaic efficiency and yield of 2,5-furandicarboxylic acid remained close to 100%over 10 consecutive electrolysis.Experimental and theoretical results unveil that the introduction of Pd atoms can modulate the local electronic structure of Ni/Co,which not only balances the competitive adsorption of HMF and OH-species,but also promote the active Ni^(3+)species formation,inducing high indirect oxidation activity.We have also discovered that Ni incorporation facilitates the Co2+pre-oxidation and electrophilic OH*generation to contribute direct oxidation process.This work provides a new approach to design advanced electrocatalyst for biomass upgrading.
基金the National Natural Science Foundation of China(Grant No.12204406)the National Key Research and Development Program of China(Grant No.2022YFA1405304)the Guangdong Provincial Key Laboratory(Grant No.2020B1212060066)。
文摘We establish a general mapping from one-dimensional non-Hermitian mosaic models to their non-mosaic counterparts.This mapping can give rise to mobility edges and even Lyapunov exponents in the mosaic models if critical points of localization or Lyapunov exponents of localized states in the corresponding non-mosaic models have already been analytically solved.To demonstrate the validity of this mapping,we apply it to two non-Hermitian localization models:an Aubry-Andre-like model with nonreciprocal hopping and complex quasiperiodic potentials,and the Ganeshan-Pixley-Das Sarma model with nonreciprocal hopping.We successfully obtain the mobility edges and Lyapunov exponents in their mosaic models.This general mapping may catalyze further studies on mobility edges,Lyapunov exponents,and other significant quantities pertaining to localization in non-Hermitian mosaic models.
文摘Rechargeable lithium metal batteries(LMBs)meet the demands of high-energy applications in electric vehicles and truck transportation[1-4].Yet,the low coulombic efficiency(CE)hinders the widespread application of Li anode,which is closely related to the electrolytes[5-7].The CE of traditional electrolytes for Li anodes is closely related to the speciation of the plated Li during cycling,where fluorinated solvents with weakly solvated Li+usually exhibit larger Li deposition particles with higher CE[8,9].But the relationship between the morphological difference and CE in different electrolytes is less studied[10,11].There are three relationships between the deposition kinetics of interface Li and the cycling of the battery,no correlation,positive correlation[12,13],and negative correlation[14,15]have been reported on active Li anodes,which neglects the reactivity of Li metal in kinetics.Solid electrolyte interphase(SEl)was formed by the electrolytes reacting with Li,and Li deposition can occur on the Li/SEl interface or the fresh Li/electrolyte interface[16,17].Each pathway has different deposition kinetics.Therefore,in order to understand the relationship between electrolyte kinetics and lithium deposition morphology,it is important to solve the kinetics of the two ways in the electrolyte.
文摘Epidermal growth factor receptor inhibitors have shown promise in the treatment of colorectal cancers. However, activating KRAS mutations cause primary resistance to these agents and contribute to cancer progression. Downstream signaling of oncogenic KRAS induces activation of HIF-1α and HIF-2α which in turn activate genes that promote cell proliferation, obstruct cell death, and induce angiogenesis and metabolic adaptation. We will discuss clinical trial results with EGFR inhibitors, mechanism of resistance mediated by oncogenic KRAS, and strategies under clinical development to overcome KRAS-mediated resistance.
基金financially supported by the National Natural Science Foundation of China(Nos.21176245,21476248)the National Science and Technology Support Program of China(Nos.2012BAJ25B02,2012BAJ25B06)the special fund of the State Key Joint Laboratory of Environment Simulation and Pollution Control(No.12L02ESPC)
文摘Nanocomposite membranes containing poly（m-phenylene isophthalamide）（PMIA） and organically modified montmorillonite（OMMT） were prepared by a combination of solution dispersion and wet-phase inversion methods, and the effects of OMMT addition on the properties and performance of fabricated nanofiltration membranes were investigated. The membranes were characterized by contact angle measurements, scanning electron microscopy（SEM）, atomic force microscopy（AFM）, thermogravimetric analysis, and zeta potential.The performance of the membranes was elucidated by the removal of perfluorooctane sulfonate（PFOS） at neutral p H. Increasing OMMT concentration improved the thermal stability and hydrophilicity of the membranes. The permeation and rejection of PFOS were significantly improved. The performance of fabricated nanofiltration membranes in removal of PFOS varied depending on the solute and membrane properties as well as solution conditions. Finally,a comparison between fabricated membranes and a commercial NF membrane（ESNA1-K1,Hydecanme） proved that the OMMT addition is a convenient procedure for producing nanocomposite membranes with superior properties and performance.
基金supported by the National Key R&D Program of China(Grant No.2022YFC2406803)the Strategic Priority Research Program of the Chinese Academy of Sciences(Grant No.XDA16010602)the National Natural Science Foundation of China(Grant Nos.81870097,82070114,and 82270126).
文摘Erythropoiesis is a finely regulated and complex process that involves multiple transformations from hematopoietic stem cells to mature red blood cells at hematopoietic sites from the embryonic to adult stages.Investigations into its molecular mechanisms have generated a wealth of expression data,including bulk and single-cell RNA sequencing data.A comprehensively integrated and well-curated erythropoiesis-specific database will greatly facilitate the mining of gene expression data and enable large-scale research of erythropoiesis and erythroid-related diseases.Here,we present EryDB,an open-access and comprehensive database dedicated to the collection,integration,analysis,and visualization of transcriptomic data for erythropoiesis and erythroid-related diseases.Currently,the database includes expertly curated quality-assured data of 3803 samples and 1,187,119 single cells derived from 107 public studies of three species(Homo sapiens,Mus musculus,and Danio rerio),nine tissue types,and five diseases.EryDB provides users with the ability to not only browse the molecular features of erythropoiesis between tissues and species,but also perform computational analyses of single-cell and bulk RNA sequencing data,thus serving as a convenient platform for customized queries and analyses.EryDB v1.0 is freely accessible at https://ngdc.cncb.ac.cn/EryDB/home.
基金Supported by the National Key Research and Development Program of China(2023YFC3007501)Natural Science Foundation of Fujian Province of China(2023J011337)Innovation Ability Promotion Plan Project of Chengdu University of Information Technology(KYQN202307)。
文摘Knowledge of raindrop size distribution(RSD)is essential for understanding microphysical processes occurring within cloud and precipitation systems,as well as for enhancing the capabilities of numerical models and radar-based quantitative precipitation estimation(QPE).However,observation and study of RSD,especially its temporal and spatial variability,remain quite limited in specific regions.One such region is Southeast China.In this paper,four years of disdrometer data from a south coastal plain site(CPS)and a north hilly inland site(HIS)in the Fujian Province of Southeast China are analyzed and compared to elucidate the characteristics and discrepancies of RSD between these two distinct climatological sites.On this basis,empirical relations between the parameters of Gamma distribution and between radar reflectivity factor(Z)and rain rate(R)are proposed.The results are summarized as follows.(1)In the cases of light to moderate rains,HIS exhibits a higher(lower)concentration of small-size(midsize and large)raindrops with diameters of D<1 mm(1≤3 and D≥3 mm),compared to CPS.Conversely,as the rain intensity increases,the raindrop concentrations across all size categories at CPS gradually exceed those at HIS.(2)RSDs at both sites broaden and exhibit elevated concentrations across most diameter categories as the rain rate increases.(3)For rainfalls with rain rates below 5 mm h^(-1),collision and coalescence dominate,resulting in unimodal rain spectra at both sites;whereas for stronger rainfalls,breakup intensifies,leading to the development of bimodal rain spectra.(4)HIS experiences more stratiform rains but fewer,weaker convective rains than CPS.Stratiform RSD at HIS possesses more small and large raindrops but fewer midsize raindrops compared to CPS,whereas convective RSD at CPS possesses higher concentrations across all diameter categories.(5)Accordingly,specific Z–R relations at these two sites are proposed and validated for two real cases,demonstrating that the accuracy of radar QPE is effectively improved based on the proposed Z–R relations.
