Pt-based catalysts are the typical industrial catalysts for propane dehydrogenation(PDH),which still suffer from insufficient lo ng-term durability due to the structu ral instability and coke deposition.A commercial ...Pt-based catalysts are the typical industrial catalysts for propane dehydrogenation(PDH),which still suffer from insufficient lo ng-term durability due to the structu ral instability and coke deposition.A commercial γ-Al_(2)O_(3) supported thermally robust sub-nanometer Pt2In3intermetallic catalyst with atomically ordered structure and rigorously separated Pt single atoms was fabricated,which showed outstanding robustness in 240 h long-term operation at 600℃ with the deactivation rate constant kdas low as0.00078 h^(-1), ranking among the lowest reported values.Based on various in situ characterizations and theoretical calculations,it was proved that the catalyst stability not only resulted from the separated Pt single-atom sites but also significantly affected by the distance of adjacent Pt atoms.An increasing distance to 3.25 A in the Pt_(2)In_(3)could induce a weak π-adsorption configuration of propylene on Pt sites,which facilitated the desorption of propylene and restrained the side reactions like coking.展开更多
Cu catalysts,known for their unparalleled catalytic capabilities due to their unique electronic structure,have faced inherent challenges in maintaining long-term effectiveness under harsh hydrogenation conditions.Here...Cu catalysts,known for their unparalleled catalytic capabilities due to their unique electronic structure,have faced inherent challenges in maintaining long-term effectiveness under harsh hydrogenation conditions.Here,we demonstrate a molybdenum-mediated redispersion behavior of Cu under hightemperature oxidation conditions.The oxidized Cu nanoparticles with rich metal-support interfaces tend to dissolve into the MoO_(3)support upon heating to 600℃,which facilitates the subsequent regeneration in a reducing atmosphere.A similar redispersion phenomenon is observed for Cu nanoparticles supported on Zn O-modified MoO_(3).The modification of ZnO significantly improves the performance of the Cu catalyst for CO_(2)hydrogenation to methanol,with the high activity being well maintained after four repeated oxidation-reduction cycles.In situ spectroscopic and theoretical analyses suggest that the interaction involved in the formation of the copper molybdate-like compound is the driving force for the redispersion of Cu.This method is applicable to various Mo-based oxide supports,offering a practical strategy for the regeneration of sintered Cu particles in hydrogenation applications.展开更多
The selective hydrogenolysis of glycerol to 1,3-propanediol is a highly important reaction for both improving the profitability of biodiesel and valorization of biomass.While intensive research efforts have been devot...The selective hydrogenolysis of glycerol to 1,3-propanediol is a highly important reaction for both improving the profitability of biodiesel and valorization of biomass.While intensive research efforts have been devoted to enhancing the catalytic activity and selectivity,little is focused on the stability although the latter is of paramount importance to practical applications.In this work,we investigated the stability of Pt/WO3/Al2O3 and observed a continuous deactivation trend during a 700 h time-on-stream run.Neither the leaching of active W nor the coking was responsible for the deactivation.Instead,XRD,HAADF-STEM and CO chemisorption results clearly showed the occurrence of significant aggregation of Pt particles,which caused a remarkable decrease of Pt-WOx interfacial sites.As a consequence,strong Br?nsted acid sites which were in situ formed by H2 dissociation at the Pt-WOx interfacial sites were reduced,leading to the deactivation of the catalyst.展开更多
Green and economical CO_(2)utilization is significant for CO_(2)emission reduction and energy development.Here,the 1D Mo_(2)C nanowires with dominant(101)crystal surfaces were modified by the deposition of atomic func...Green and economical CO_(2)utilization is significant for CO_(2)emission reduction and energy development.Here,the 1D Mo_(2)C nanowires with dominant(101)crystal surfaces were modified by the deposition of atomic functional components Rh and K.While unmodifiedβMo_(2)C could only convert CO_(2)to methanol,the designed catalyst of K_(0.2)Rh_(0.2)/β-Mo_(2)C exhibited up to 72.1%of ethanol selectivity at 150℃.It was observed that the atomically dispersed Rh could form the bifunctional active centres with the active carrierβMo_(2)C with the synergistic effects to achieve highly specific controlled C–C coupling.By promoting the CO_(2)adsorption and activation,the introduction of an alkali metal(K)mainly regulated the balanced performance of the two active centres,which in turn improved the hydrogenation selectivity.Overall,the controlled modification ofβMo_(2)C provides a new design strategy for the highly efficient,lowtemperature hydrogenation of CO_(2)to ethanol with single-atom catalysts,which provides an excellent example for the rational design of the complex catalysts.展开更多
Selective aerobic oxidation of alcohols under mild conditions is of great importance yet challenging,with the activation of molecular oxygen(O2)as a crucial capability of the catalysts.Herein,we demonstrate that an Al...Selective aerobic oxidation of alcohols under mild conditions is of great importance yet challenging,with the activation of molecular oxygen(O2)as a crucial capability of the catalysts.Herein,we demonstrate that an Al2O3-supported Pd single-atom catalyst leads to higher activity and selectivity compared to Pd nanoparticles for the oxidation of cinnamyl alcohol.The Al2O3 support used in this study is rich in coordinately unsaturated Al3+sites,which are apt for binding to Pd atoms through oxygen bridges and present a distinct metal-support interaction(MSI).The suitable MSI then leads to a unique electronic characteristic of the Pd single atoms,which can be confirmed via X-ray photoelectron spectroscopy,normalized X-ray absorption near-edge structure,and diffuse reflectance Fourier transform infrared spectroscopy.Moreover,this unique electronic state is proposed to be responsible for its high catalytic activity.With the help of in-situ UV-vis spectra and electron spin resonance spectra,a specific alcohol oxidation route with O2 activation mechanism is then identified.Active oxygen species behaving chemically like singlet-O2 are generated from the interaction of O2 with Pd1/Al2O3,and then oxidize the partially dehydrogenated intermediates produced by the adsorbed allylic alcohols and Pd atoms to the desired alkenyl aldehyde.This work provides a promising path for the design and development of high-activity catalysts for aerobic oxidation reactions.展开更多
Catalytic ethane dehydrogenation(EDH) to ethylene over Pt-based catalysts has received increasing interests in recent years as it is a potential alternative route to conventional steam cracking. However, the catalysts...Catalytic ethane dehydrogenation(EDH) to ethylene over Pt-based catalysts has received increasing interests in recent years as it is a potential alternative route to conventional steam cracking. However, the catalysts used in this reaction often suffer from rapid deactivation due to serious coke deposition and metal sintering. Herein, we reported the effects of Zn modification on the stability of Pt/Al2 O3 for EDH.The Zn-modified sample(PtZn2/Al2 O3) exhibits stable ethane conversion(20%) with over 95% ethylene selectivity. More importantly, it exhibits a significantly low deactivation rate of only 0.003 h-1 at 600 °C for70 h, which surpasses most of previously reported catalysts. Detailed characterizations including in situ FT-IR, ethylene adsorption microcalorimetry, and HAADF-STEM etc. reveal that Zn modifier reduces the number of Lewis acid sites on the catalyst surface. Moreover, it could modify Pt sites and preferentially cover the step sites, which decrease surface energy and retard the sintering of Pt particle, then prohibiting the further dehydrogenation of ethylene to ethylidyne. Consequently, the good stability is realized due to anti-sintering and the decrease of coke formation on the Pt Zn2/Al2 O3 catalyst.展开更多
The performance of lignin depolymerization is basically determined by the interunit C–O and C–C bonds.Numerous C–O bond cleavage strategies have been developed, while the cleavage of C–C bond between the primary a...The performance of lignin depolymerization is basically determined by the interunit C–O and C–C bonds.Numerous C–O bond cleavage strategies have been developed, while the cleavage of C–C bond between the primary aromatic units remains a challenging task due to the high dissociation energy of C–C bond.Herein, a multifunctional Ru Re alloy catalyst was designed, which exhibited exceptional catalytic activity for the cleavage of both C–O and C–C linkages in a broad range of lignin model compounds(β-1, a-5, 5–5,β-O-4, 4-O-5) and two stubborn lignins(kraft lignin and alkaline lignin), affording 97.5% overall yield of monocyclic compounds from model compounds and up to 129% of the maximum theoretical yield of monocyclic products based on C–O bonds cleavage from realistic lignin. Scanning transmission electron microscopy(STEM) characterization showed that Ru Re(1:1) alloy particles with hexagonal close-packed structure were homogeneously dispersed on the support. Quasi-in situ X-ray photoelectron spectroscopy(XPS), and X-ray absorption spectroscopy(XAS) indicate that Ru species were predominantly metallic state, whereas Re species were partially oxidized;meanwhile, there was a strong interaction between Ru and Re, where the electron transfer from Re to Ru was occurred, resulting in great improvement on the capability of C–O and C–C bonds cleavage in lignin conversion.展开更多
This paper reports a new strategy for the structural reconstruction of biomass carbon sulfonic acid(BCSA)to its solid superacid counterpart.In this approach,a cheap layered biomass carbon(BC)source is chemically exfol...This paper reports a new strategy for the structural reconstruction of biomass carbon sulfonic acid(BCSA)to its solid superacid counterpart.In this approach,a cheap layered biomass carbon(BC)source is chemically exfoliated by cetyltrimethyl ammonium bromide and then converted to silica-isolated carbon nanosheets(CNSs)by a series of conversion steps.The state of the silica-isolated CNSs and the stacking density of their nanoparticles are regulated by the dehydration temperature.Only the highly isolated and non-crosslinked CNSs with loose particle stacking structures obtained upon dehydration at 250℃ can be turned into superacid sites(with stronger acidity than that of 100%H2 SO4)after sulfonation.This is accompanied by the creation of abundant hierarchical slit pores with high external surface area,mainly driven by the strong hydrogen bonding interactions between the introduced sulfonic acid groups.In typical acid-catalyzed esterification,etherification,and hydrolysis reactions,the newly formed superacid exhibits superior catalytic activity and stability compared to those of common BCSA and commercial Amberlyst-15 catalysts,owing to its good structural stability,highly exposed stable superacidic sites,and abundance of mesoporous/macroporous channels with excellent mass transfer rate.This groundbreaking work not only provides a novel strategy for fabricating bio-based solid superacids,but also overcomes the drawbacks of BCSA,i.e.,unsatisfactory structural stability,acidity,and porosity.展开更多
Thermochemical two-step CO_(2) splitting is a potential approach that fixes the sustainable resource into transportable liquid fuels.However,the harsh CO_(2) splitting conditions,the limited oxygen release kinetics an...Thermochemical two-step CO_(2) splitting is a potential approach that fixes the sustainable resource into transportable liquid fuels.However,the harsh CO_(2) splitting conditions,the limited oxygen release kinetics and capacity of metal oxides block further promoted the CO yield and solar-to-fuel energy efficiency.Here,we propose a different carbon cycle assisted by Ni/La_(2)O_(3) via coupling methane decomposition with thermochemical CO_(2) splitting,replacing conventional metal oxides cycle.Superior performance was demonstrated with methane conversion reached around 94%with almost pure H_(2) generation.Encouragingly,CO_(2) conversion of 98%and CO yield of 6.9 mmol g^(-1) derived from CO_(2) were achieved,with peak CO evolution rate(402 mL min^(-1) g^(-1))of orders of magnitude higher than that in metal oxide process and outstanding thermodynamic solar-to-fuel energy efficiency(55.5%vs.18.5%).This was relevant to the synergistic activation of La_(2)O_(3) and Ni for CO_(2) in carbon cycle,thus improving CO_(2) splitting reaction with carbon species.展开更多
The efficacy of adaptive immune responses in cancer treatment relies heavily on the state of the T cells.Upon antigen exposure,T cells undergo metabolic reprogramming,leading to the development of functional effectors...The efficacy of adaptive immune responses in cancer treatment relies heavily on the state of the T cells.Upon antigen exposure,T cells undergo metabolic reprogramming,leading to the development of functional effectors or memory populations.However,within the tumor microenvironment(TME),metabolic stress impairs CD8+T cell anti-tumor immunity,resulting in exhausted differentiation.Recent studies suggested that targeting T cell metabolism could offer promising therapeutic opportunities to enhance T cell immunotherapy.In this review,we provide a comprehensive summary of the intrinsic and extrinsic factors necessary for metabolic reprogramming during the development of effector and memory T cells in response to acute and chronic inflammatory conditions.Furthermore,we delved into the different metabolic switches that occur during T cell exhaustion,exploring how prolonged metabolic stress within the TME triggers alterations in cellular metabolism and the epigenetic landscape that contribute to T cell exhaustion,ultimately leading to a persistently exhausted state.Understanding the intricate relationship between T cell metabolism and cancer immunotherapy can lead to the development of novel approaches to improve the efficacy of T cell-based treatments against cancer.展开更多
Abstract To date, we still lack disease-modifying thera- pies for Alzheimer＇s disease （AD）. Here, we report that long-term administration of benfotiamine improved the cognitive ability of patients with AD. Five pat...Abstract To date, we still lack disease-modifying thera- pies for Alzheimer＇s disease （AD）. Here, we report that long-term administration of benfotiamine improved the cognitive ability of patients with AD. Five patients with mild to moderate AD received oral benfotiamine （300 mg daily） over 18 months. All patients were examined by positron emission tomography with Pittsburgh compound B （PiB-PET） and exhibited positive imaging with β- amyloid deposition, and three received PiB-PET imaging at follow-up. The five patients exhibited cognitive improve- ment as assayed by the Mini-Mental Status Examination （MMSE） with an average increase of 3.2 points at month 18 of benfotiamine administration. The three patients who received follow-up PiB-PET had a 36.7% increase in the average standardized uptake value ratio in the brain com- pared with that in the first scan. Importantly, the MMSE scores of these three had an average increase of 3 points during the same period. Benfotiamine significantly improved the cognitive abilities of mild to moderate AD patients independently of brain amyloid accumulation. Ourstudy provides new insight to the development of disease- modifying therapy.展开更多
The mitogen-activated protein kinase(MAPK)/extracellular signal-regulated kinase 1/2(ERK1/2) signaling pathway is widely activated by a variety of extracellular stimuli, and its dysregulation is associated with the pr...The mitogen-activated protein kinase(MAPK)/extracellular signal-regulated kinase 1/2(ERK1/2) signaling pathway is widely activated by a variety of extracellular stimuli, and its dysregulation is associated with the proliferation, invasion, and migration of cancer cells. ERK1/2 is located at the distal end of this pathway and rarely undergoes mutations, making it an attractive target for anticancer drug development. Currently, an increasing number of ERK1/2 inhibitors have been designed and synthesized for antitumor therapy, among which representative compounds have entered clinical trials. When ERK1/2 signal transduction is eliminated, ERK5 may provide a bypass route to rescue proliferation, and weaken the potency of ERK1/2 inhibitors. Therefore, drug research targeting ERK5 or based on the compensatory mechanism of ERK5 for ERK1/2 opens up a new way for oncotherapy. This review provides an overview of the physiological and biological functions of ERKs, focuses on the structure-activity relationships of small molecule inhibitors targeting ERKs, with a view to providing guidance for future drug design and optimization, and discusses the potential therapeutic strategies to overcome drug resistance.展开更多
Heterogenization of the homogeneous catalysis has been studied for almost 50 years.Single-atom catalysis has the advantages of both homo-and heterogeneous catalysis.It has been proposed,and subsequently experimentally...Heterogenization of the homogeneous catalysis has been studied for almost 50 years.Single-atom catalysis has the advantages of both homo-and heterogeneous catalysis.It has been proposed,and subsequently experimentally verified that single-atom catalysis is able to bridge homo-and heterogeneous catalysis,thus providing a new avenue to realize the heterogenization of homogeneous catalysis.Alkoxycarbonylation of aryl halides is an effective method for the direct synthesis of carboxylic acid derivatives,and is commonly catalyzed by Pd-based homogeneous complexes with N/P-containing ligands and organic/inorganic base.Herein,we firstly reported that Pd1/CeO2 single-atom catalyst showed good performance in the alkoxycarbonylation of aryl iodides reaction.Under base-free and ligand-free conditions,Pd1/CeO2 single-atom catalyst can transfer different aryl iodides to corresponding products.The catalyst can be easily recovered and reused four times without significant loss of reactivity.展开更多
Non-alcoholic fatty liver disease (NAFLD) is emerging as the most common chronic liver disease worldwide. It refers to a range of liver conditions affecting people who drink little or no alcohol. NAFLD comprises non-a...Non-alcoholic fatty liver disease (NAFLD) is emerging as the most common chronic liver disease worldwide. It refers to a range of liver conditions affecting people who drink little or no alcohol. NAFLD comprises non-alcoholic fatty liver and non-alcoholic steatohepatitis (NASH), the more aggressive form of NAFLD. NASH is featured by steatosis, lobular inflammation, hepatocyte injury, and various degrees of fibrosis. Although much progress has been made over the past decades, the pathogenic mechanism of NAFLD remains to be fully elucidated. Hepatocyte nuclear factor 4α (HNF4α) is a nuclear hormone receptor that is highly expressed in hepatocytes. Hepatic HNF4α expression is markedly reduced in NAFLD patients and mouse models of NASH. HNF4α has been shown to regulate bile acid, lipid, glucose, and drug metabolism. In this review, we summarize the recent advances in the understanding of the pathogenesis of NAFLD with a focus on the regulation of HNF4α and the role of hepatic HNF4α in NAFLD. Several lines of evidence have shown that hepatic HNF4α plays a key role in the initiation and progression of NAFLD. Recent data suggest that hepatic HNF4α may be a promising target for treatment of NAFLD.展开更多
Thiamine metabolism is critical for glucose metabolism and also vital for brain function, which is susceptible to decline in the elderly. This study aimed to investigate whether thiamine metabolites correlate with cog...Thiamine metabolism is critical for glucose metabolism and also vital for brain function, which is susceptible to decline in the elderly. This study aimed to investigate whether thiamine metabolites correlate with cognitive function in the non-demented elderly and their impact factors. Volunteers 〉60 years old were recruited and their blood thiamine metabolites and Mini-Mental State Examination （MMSE） scores were measured. The apolipoprotein E （APOE） genotype, routine blood parameters, liver and kidney function, and levels of fasting blood glucose and triglycerides were also measured. The results showed that the thiamine diphosphate （TDP） level weakly correlated with MMSE score in the non-demented elderly. Participants with high TDP levels performed better in Recall and Attention and Calculation than those with low TDP. TDP levels were associated with the APOE E2 allele, body mass index, hemoglobin level, fasting blood glucose, and triglycerides. Our results suggest that TDP, which is easily affected by many factors, impacts cognitive function in the elderly.展开更多
The physiological functions of endogenous amyloid-β(Aβ),which plays important role in the pathology of Alzheimer's disease(AD),have not been paid enough attention.Here,we review the multiple physiological effect...The physiological functions of endogenous amyloid-β(Aβ),which plays important role in the pathology of Alzheimer's disease(AD),have not been paid enough attention.Here,we review the multiple physiological effects of Aβ,particularly in regulating synaptic transmission,and the possible mechanisms,in order to decipher the real characters of Aβunder both physiological and pathological conditions.Some worthy studies have shown that the deprivation of endogenous Aβgives rise to synaptic dysfunction and cognitive deficiency,while the moderate elevation of this peptide enhances long term potentiation and leads to neuronal hyperexcitability.In this review,we provide a new view for understanding the role of Aβin AD pathophysiology from the perspective of physiological meaning.展开更多
Alzheimer’s disease(AD),the most common type of dementia,is a devastating neurodegenerative disorder that seriously afflicts millions of patients and their families due to the lack of effective therapeutic drugs and ...Alzheimer’s disease(AD),the most common type of dementia,is a devastating neurodegenerative disorder that seriously afflicts millions of patients and their families due to the lack of effective therapeutic drugs and methods.Elucidating the pathogenesis of this disease has always been a great challenge because AD is complicated with multiple pathophysiological features,including neurodegeneration characterized by progressive synaptic/neuronal loss leading to brain atrophy,brain Aβ deposition forming plaques,Tau hyperphosphorylation constituting neurofibrillary tangles,glial activation and neuroinflammation,and glucose hypometabolism.展开更多
基金financially supported by the DNL Cooperation Fund,CAS (DNL202002)the National Natural Science Foundation of China (22102180)+3 种基金the CAS Project for Young Scientists in Basic Research,(YSBR-022)the Key Research Program of Frontier Sciences,CAS (ZDBS-LY-7012)Liao Ning Revitalization Talents Program (XLYC2007070)the Fundamental Research Funds for the Central Universities (20720220009)。
文摘Pt-based catalysts are the typical industrial catalysts for propane dehydrogenation(PDH),which still suffer from insufficient lo ng-term durability due to the structu ral instability and coke deposition.A commercial γ-Al_(2)O_(3) supported thermally robust sub-nanometer Pt2In3intermetallic catalyst with atomically ordered structure and rigorously separated Pt single atoms was fabricated,which showed outstanding robustness in 240 h long-term operation at 600℃ with the deactivation rate constant kdas low as0.00078 h^(-1), ranking among the lowest reported values.Based on various in situ characterizations and theoretical calculations,it was proved that the catalyst stability not only resulted from the separated Pt single-atom sites but also significantly affected by the distance of adjacent Pt atoms.An increasing distance to 3.25 A in the Pt_(2)In_(3)could induce a weak π-adsorption configuration of propylene on Pt sites,which facilitated the desorption of propylene and restrained the side reactions like coking.
基金the National Key Research and Development Program of China[No.2021YFB4000700]the CAS Project for Young Scientists in Basic Research[YSBR-022]+1 种基金the National Natural Science Foundation of China[22008136,21925803]the Welsh Government funded Taith Research Mobility Programme[No.524339]。
文摘Cu catalysts,known for their unparalleled catalytic capabilities due to their unique electronic structure,have faced inherent challenges in maintaining long-term effectiveness under harsh hydrogenation conditions.Here,we demonstrate a molybdenum-mediated redispersion behavior of Cu under hightemperature oxidation conditions.The oxidized Cu nanoparticles with rich metal-support interfaces tend to dissolve into the MoO_(3)support upon heating to 600℃,which facilitates the subsequent regeneration in a reducing atmosphere.A similar redispersion phenomenon is observed for Cu nanoparticles supported on Zn O-modified MoO_(3).The modification of ZnO significantly improves the performance of the Cu catalyst for CO_(2)hydrogenation to methanol,with the high activity being well maintained after four repeated oxidation-reduction cycles.In situ spectroscopic and theoretical analyses suggest that the interaction involved in the formation of the copper molybdate-like compound is the driving force for the redispersion of Cu.This method is applicable to various Mo-based oxide supports,offering a practical strategy for the regeneration of sintered Cu particles in hydrogenation applications.
文摘The selective hydrogenolysis of glycerol to 1,3-propanediol is a highly important reaction for both improving the profitability of biodiesel and valorization of biomass.While intensive research efforts have been devoted to enhancing the catalytic activity and selectivity,little is focused on the stability although the latter is of paramount importance to practical applications.In this work,we investigated the stability of Pt/WO3/Al2O3 and observed a continuous deactivation trend during a 700 h time-on-stream run.Neither the leaching of active W nor the coking was responsible for the deactivation.Instead,XRD,HAADF-STEM and CO chemisorption results clearly showed the occurrence of significant aggregation of Pt particles,which caused a remarkable decrease of Pt-WOx interfacial sites.As a consequence,strong Br?nsted acid sites which were in situ formed by H2 dissociation at the Pt-WOx interfacial sites were reduced,leading to the deactivation of the catalyst.
基金financially supported by the National Natural Science Foundation of China(21925803,U19A2015)the Strategic Priority Research Program of the Chinese Academy of Sciences(XDB36030200)the Liao Ning Revitalization Talents Program(XLYC1907170).
文摘Green and economical CO_(2)utilization is significant for CO_(2)emission reduction and energy development.Here,the 1D Mo_(2)C nanowires with dominant(101)crystal surfaces were modified by the deposition of atomic functional components Rh and K.While unmodifiedβMo_(2)C could only convert CO_(2)to methanol,the designed catalyst of K_(0.2)Rh_(0.2)/β-Mo_(2)C exhibited up to 72.1%of ethanol selectivity at 150℃.It was observed that the atomically dispersed Rh could form the bifunctional active centres with the active carrierβMo_(2)C with the synergistic effects to achieve highly specific controlled C–C coupling.By promoting the CO_(2)adsorption and activation,the introduction of an alkali metal(K)mainly regulated the balanced performance of the two active centres,which in turn improved the hydrogenation selectivity.Overall,the controlled modification ofβMo_(2)C provides a new design strategy for the highly efficient,lowtemperature hydrogenation of CO_(2)to ethanol with single-atom catalysts,which provides an excellent example for the rational design of the complex catalysts.
文摘Selective aerobic oxidation of alcohols under mild conditions is of great importance yet challenging,with the activation of molecular oxygen(O2)as a crucial capability of the catalysts.Herein,we demonstrate that an Al2O3-supported Pd single-atom catalyst leads to higher activity and selectivity compared to Pd nanoparticles for the oxidation of cinnamyl alcohol.The Al2O3 support used in this study is rich in coordinately unsaturated Al3+sites,which are apt for binding to Pd atoms through oxygen bridges and present a distinct metal-support interaction(MSI).The suitable MSI then leads to a unique electronic characteristic of the Pd single atoms,which can be confirmed via X-ray photoelectron spectroscopy,normalized X-ray absorption near-edge structure,and diffuse reflectance Fourier transform infrared spectroscopy.Moreover,this unique electronic state is proposed to be responsible for its high catalytic activity.With the help of in-situ UV-vis spectra and electron spin resonance spectra,a specific alcohol oxidation route with O2 activation mechanism is then identified.Active oxygen species behaving chemically like singlet-O2 are generated from the interaction of O2 with Pd1/Al2O3,and then oxidize the partially dehydrogenated intermediates produced by the adsorbed allylic alcohols and Pd atoms to the desired alkenyl aldehyde.This work provides a promising path for the design and development of high-activity catalysts for aerobic oxidation reactions.
基金supported by the National Natural Science Foundation of China (NNSFC 21573232, 21576251, 21676269, 21878283)the Strategic Priority Research Program of Chinese Academy of Sciences Grant No. XDB17000000+2 种基金National Key Projects for Fundamental Research and Development of China (2016YFA0202801)The Youth Innovation Promotion Association CAS (2017223)Department of Science and Technology of Liaoning province under contract of 2015020086-101。
文摘Catalytic ethane dehydrogenation(EDH) to ethylene over Pt-based catalysts has received increasing interests in recent years as it is a potential alternative route to conventional steam cracking. However, the catalysts used in this reaction often suffer from rapid deactivation due to serious coke deposition and metal sintering. Herein, we reported the effects of Zn modification on the stability of Pt/Al2 O3 for EDH.The Zn-modified sample(PtZn2/Al2 O3) exhibits stable ethane conversion(20%) with over 95% ethylene selectivity. More importantly, it exhibits a significantly low deactivation rate of only 0.003 h-1 at 600 °C for70 h, which surpasses most of previously reported catalysts. Detailed characterizations including in situ FT-IR, ethylene adsorption microcalorimetry, and HAADF-STEM etc. reveal that Zn modifier reduces the number of Lewis acid sites on the catalyst surface. Moreover, it could modify Pt sites and preferentially cover the step sites, which decrease surface energy and retard the sintering of Pt particle, then prohibiting the further dehydrogenation of ethylene to ethylidyne. Consequently, the good stability is realized due to anti-sintering and the decrease of coke formation on the Pt Zn2/Al2 O3 catalyst.
基金The National Natural Science Foundation of China(22078317,21878288,21721004,21690083)。
文摘The performance of lignin depolymerization is basically determined by the interunit C–O and C–C bonds.Numerous C–O bond cleavage strategies have been developed, while the cleavage of C–C bond between the primary aromatic units remains a challenging task due to the high dissociation energy of C–C bond.Herein, a multifunctional Ru Re alloy catalyst was designed, which exhibited exceptional catalytic activity for the cleavage of both C–O and C–C linkages in a broad range of lignin model compounds(β-1, a-5, 5–5,β-O-4, 4-O-5) and two stubborn lignins(kraft lignin and alkaline lignin), affording 97.5% overall yield of monocyclic compounds from model compounds and up to 129% of the maximum theoretical yield of monocyclic products based on C–O bonds cleavage from realistic lignin. Scanning transmission electron microscopy(STEM) characterization showed that Ru Re(1:1) alloy particles with hexagonal close-packed structure were homogeneously dispersed on the support. Quasi-in situ X-ray photoelectron spectroscopy(XPS), and X-ray absorption spectroscopy(XAS) indicate that Ru species were predominantly metallic state, whereas Re species were partially oxidized;meanwhile, there was a strong interaction between Ru and Re, where the electron transfer from Re to Ru was occurred, resulting in great improvement on the capability of C–O and C–C bonds cleavage in lignin conversion.
基金financial support for this work by the National Natural Science Foundation of China(21690080,21676079,21546010,21690083,21878288)the Strategic Priority Research Program of Chinese Academy of Sciences(XDB17020100)+2 种基金DNL Cooperation Fund CAS(DNL180302)the Natural Science Foundation of Hunan Province(2018JJ3335)the Innovation Platform Open Fund of Hunan College(18K016)~~
文摘This paper reports a new strategy for the structural reconstruction of biomass carbon sulfonic acid(BCSA)to its solid superacid counterpart.In this approach,a cheap layered biomass carbon(BC)source is chemically exfoliated by cetyltrimethyl ammonium bromide and then converted to silica-isolated carbon nanosheets(CNSs)by a series of conversion steps.The state of the silica-isolated CNSs and the stacking density of their nanoparticles are regulated by the dehydration temperature.Only the highly isolated and non-crosslinked CNSs with loose particle stacking structures obtained upon dehydration at 250℃ can be turned into superacid sites(with stronger acidity than that of 100%H2 SO4)after sulfonation.This is accompanied by the creation of abundant hierarchical slit pores with high external surface area,mainly driven by the strong hydrogen bonding interactions between the introduced sulfonic acid groups.In typical acid-catalyzed esterification,etherification,and hydrolysis reactions,the newly formed superacid exhibits superior catalytic activity and stability compared to those of common BCSA and commercial Amberlyst-15 catalysts,owing to its good structural stability,highly exposed stable superacidic sites,and abundance of mesoporous/macroporous channels with excellent mass transfer rate.This groundbreaking work not only provides a novel strategy for fabricating bio-based solid superacids,but also overcomes the drawbacks of BCSA,i.e.,unsatisfactory structural stability,acidity,and porosity.
基金supported by the Strategic Priority Research Program of the Chinese Academy of Sciences(XDB17020100)the National Key R&D Program of China(2016YFA0202-801)+1 种基金the National Natural Science Foundation of China(NSFC)grants(21676269,21706254,21878283,22022814)the Dalian Institute of Chemical Physics,CAS(DICP I201916)。
文摘Thermochemical two-step CO_(2) splitting is a potential approach that fixes the sustainable resource into transportable liquid fuels.However,the harsh CO_(2) splitting conditions,the limited oxygen release kinetics and capacity of metal oxides block further promoted the CO yield and solar-to-fuel energy efficiency.Here,we propose a different carbon cycle assisted by Ni/La_(2)O_(3) via coupling methane decomposition with thermochemical CO_(2) splitting,replacing conventional metal oxides cycle.Superior performance was demonstrated with methane conversion reached around 94%with almost pure H_(2) generation.Encouragingly,CO_(2) conversion of 98%and CO yield of 6.9 mmol g^(-1) derived from CO_(2) were achieved,with peak CO evolution rate(402 mL min^(-1) g^(-1))of orders of magnitude higher than that in metal oxide process and outstanding thermodynamic solar-to-fuel energy efficiency(55.5%vs.18.5%).This was relevant to the synergistic activation of La_(2)O_(3) and Ni for CO_(2) in carbon cycle,thus improving CO_(2) splitting reaction with carbon species.
基金National Natural Science Foundation of China(Nos.81788101,82271775,and 81972875)Chinese Academy of Medical Sciences Innovation Fund for Medical Sciences(Nos.2021-I2M-1-021,2021-I2M-1-061,and 2022-I2M-1-047)+1 种基金Haihe Laboratory of Cell Ecosystem Innovation Fund(No.22HHXBSS00009)Natural Science Foundation Outstanding Youth Fund of Jiangsu Province(Nos.BK20220049 and BK20211505)
文摘The efficacy of adaptive immune responses in cancer treatment relies heavily on the state of the T cells.Upon antigen exposure,T cells undergo metabolic reprogramming,leading to the development of functional effectors or memory populations.However,within the tumor microenvironment(TME),metabolic stress impairs CD8+T cell anti-tumor immunity,resulting in exhausted differentiation.Recent studies suggested that targeting T cell metabolism could offer promising therapeutic opportunities to enhance T cell immunotherapy.In this review,we provide a comprehensive summary of the intrinsic and extrinsic factors necessary for metabolic reprogramming during the development of effector and memory T cells in response to acute and chronic inflammatory conditions.Furthermore,we delved into the different metabolic switches that occur during T cell exhaustion,exploring how prolonged metabolic stress within the TME triggers alterations in cellular metabolism and the epigenetic landscape that contribute to T cell exhaustion,ultimately leading to a persistently exhausted state.Understanding the intricate relationship between T cell metabolism and cancer immunotherapy can lead to the development of novel approaches to improve the efficacy of T cell-based treatments against cancer.
基金supported by the Key Fund for Developing New Drugs from the Ministry of Science and Technology of China(2014ZX09101005-005)the National Natural Science Foundation of China(81071019)+2 种基金the National Key Basic Research Program of China(2011CBA00400)the Natural Science Foundation of Shanghai Municipality,China(13JC1401500)the Fund for Medical Emerging Cutting-Edge Technology in Shanghai of China (SHDC12012114)
文摘Abstract To date, we still lack disease-modifying thera- pies for Alzheimer＇s disease （AD）. Here, we report that long-term administration of benfotiamine improved the cognitive ability of patients with AD. Five patients with mild to moderate AD received oral benfotiamine （300 mg daily） over 18 months. All patients were examined by positron emission tomography with Pittsburgh compound B （PiB-PET） and exhibited positive imaging with β- amyloid deposition, and three received PiB-PET imaging at follow-up. The five patients exhibited cognitive improve- ment as assayed by the Mini-Mental Status Examination （MMSE） with an average increase of 3.2 points at month 18 of benfotiamine administration. The three patients who received follow-up PiB-PET had a 36.7% increase in the average standardized uptake value ratio in the brain com- pared with that in the first scan. Importantly, the MMSE scores of these three had an average increase of 3 points during the same period. Benfotiamine significantly improved the cognitive abilities of mild to moderate AD patients independently of brain amyloid accumulation. Ourstudy provides new insight to the development of disease- modifying therapy.
基金supported by grants from the National Natural Science Foundation of China (Grants 22177083,81922064,81874290,and 81803755)Sichuan Science and Technology Program (Grant No.2020JDRC0053,China)+1 种基金Fundamental Research Funds for the Central Universities (Grant No.2682020CX56,China)National Clinical Research Center for Geriatrics,West China Hospital,Sichuan University (Grant Z20201004,China)。
文摘The mitogen-activated protein kinase(MAPK)/extracellular signal-regulated kinase 1/2(ERK1/2) signaling pathway is widely activated by a variety of extracellular stimuli, and its dysregulation is associated with the proliferation, invasion, and migration of cancer cells. ERK1/2 is located at the distal end of this pathway and rarely undergoes mutations, making it an attractive target for anticancer drug development. Currently, an increasing number of ERK1/2 inhibitors have been designed and synthesized for antitumor therapy, among which representative compounds have entered clinical trials. When ERK1/2 signal transduction is eliminated, ERK5 may provide a bypass route to rescue proliferation, and weaken the potency of ERK1/2 inhibitors. Therefore, drug research targeting ERK5 or based on the compensatory mechanism of ERK5 for ERK1/2 opens up a new way for oncotherapy. This review provides an overview of the physiological and biological functions of ERKs, focuses on the structure-activity relationships of small molecule inhibitors targeting ERKs, with a view to providing guidance for future drug design and optimization, and discusses the potential therapeutic strategies to overcome drug resistance.
基金financially supported by the National Natural Science Foundation of China (21776270)the Strategic Priority Research Program of the Chinese Academy of Sciences(XDB17020100)+3 种基金China Postdoctoral Science Foundation(2017M621170)DICP Outstanding Postdoctoral Foundation(2017YB02)Liaoning Revitalization Talents Programdedicated funds for methanol conversion from DICP
文摘Heterogenization of the homogeneous catalysis has been studied for almost 50 years.Single-atom catalysis has the advantages of both homo-and heterogeneous catalysis.It has been proposed,and subsequently experimentally verified that single-atom catalysis is able to bridge homo-and heterogeneous catalysis,thus providing a new avenue to realize the heterogenization of homogeneous catalysis.Alkoxycarbonylation of aryl halides is an effective method for the direct synthesis of carboxylic acid derivatives,and is commonly catalyzed by Pd-based homogeneous complexes with N/P-containing ligands and organic/inorganic base.Herein,we firstly reported that Pd1/CeO2 single-atom catalyst showed good performance in the alkoxycarbonylation of aryl iodides reaction.Under base-free and ligand-free conditions,Pd1/CeO2 single-atom catalyst can transfer different aryl iodides to corresponding products.The catalyst can be easily recovered and reused four times without significant loss of reactivity.
基金This work is supported by the grants from National Institutes of Health(R01DK102619, R01DK118941, R01DK118805, and R0DK121548)。
文摘Non-alcoholic fatty liver disease (NAFLD) is emerging as the most common chronic liver disease worldwide. It refers to a range of liver conditions affecting people who drink little or no alcohol. NAFLD comprises non-alcoholic fatty liver and non-alcoholic steatohepatitis (NASH), the more aggressive form of NAFLD. NASH is featured by steatosis, lobular inflammation, hepatocyte injury, and various degrees of fibrosis. Although much progress has been made over the past decades, the pathogenic mechanism of NAFLD remains to be fully elucidated. Hepatocyte nuclear factor 4α (HNF4α) is a nuclear hormone receptor that is highly expressed in hepatocytes. Hepatic HNF4α expression is markedly reduced in NAFLD patients and mouse models of NASH. HNF4α has been shown to regulate bile acid, lipid, glucose, and drug metabolism. In this review, we summarize the recent advances in the understanding of the pathogenesis of NAFLD with a focus on the regulation of HNF4α and the role of hepatic HNF4α in NAFLD. Several lines of evidence have shown that hepatic HNF4α plays a key role in the initiation and progression of NAFLD. Recent data suggest that hepatic HNF4α may be a promising target for treatment of NAFLD.
基金supported by the National Basic Research Development Program (973 Program) of China (2011CBA00400)the National Natural Science Foundation of China (91332201)+1 种基金the Natural Science Foundation of Shanghai Municipality, China (13JC1401501)the Fund for Medical Emerging Cutting-edge Technology of Shanghai Municipality, China (SHDC12012114)
文摘Thiamine metabolism is critical for glucose metabolism and also vital for brain function, which is susceptible to decline in the elderly. This study aimed to investigate whether thiamine metabolites correlate with cognitive function in the non-demented elderly and their impact factors. Volunteers 〉60 years old were recruited and their blood thiamine metabolites and Mini-Mental State Examination （MMSE） scores were measured. The apolipoprotein E （APOE） genotype, routine blood parameters, liver and kidney function, and levels of fasting blood glucose and triglycerides were also measured. The results showed that the thiamine diphosphate （TDP） level weakly correlated with MMSE score in the non-demented elderly. Participants with high TDP levels performed better in Recall and Attention and Calculation than those with low TDP. TDP levels were associated with the APOE E2 allele, body mass index, hemoglobin level, fasting blood glucose, and triglycerides. Our results suggest that TDP, which is easily affected by many factors, impacts cognitive function in the elderly.
基金supported by grants from the Shanghai Municipal Science and Technology Major Project,the National Key Research and Development Program Foundation of China(2016YFC1306403)the National Natural Science Foundation of China(81870822,91332201,81901081,81600930,82171408,82171411)the Natural Science Foundation of Fujian Province(2020CXB049).
文摘The physiological functions of endogenous amyloid-β(Aβ),which plays important role in the pathology of Alzheimer's disease(AD),have not been paid enough attention.Here,we review the multiple physiological effects of Aβ,particularly in regulating synaptic transmission,and the possible mechanisms,in order to decipher the real characters of Aβunder both physiological and pathological conditions.Some worthy studies have shown that the deprivation of endogenous Aβgives rise to synaptic dysfunction and cognitive deficiency,while the moderate elevation of this peptide enhances long term potentiation and leads to neuronal hyperexcitability.In this review,we provide a new view for understanding the role of Aβin AD pathophysiology from the perspective of physiological meaning.
基金This research highlight was supported by the National Natural Science Foundation of China(81870822,91332201,81901081,and 81600930)the National Key Research and Development Program of China(2016YFC1306403)a Shanghai Municipal Science and Technology Major Project(2018SHZDZX01).
文摘Alzheimer’s disease(AD),the most common type of dementia,is a devastating neurodegenerative disorder that seriously afflicts millions of patients and their families due to the lack of effective therapeutic drugs and methods.Elucidating the pathogenesis of this disease has always been a great challenge because AD is complicated with multiple pathophysiological features,including neurodegeneration characterized by progressive synaptic/neuronal loss leading to brain atrophy,brain Aβ deposition forming plaques,Tau hyperphosphorylation constituting neurofibrillary tangles,glial activation and neuroinflammation,and glucose hypometabolism.
