Relative reactivities of polyhalofluoroalkanes toward bromophilic or chlorophilic attacks have been evaluated for the first time by comparing the rates of halophilic attacks by a carbanion derived from the addition of...Relative reactivities of polyhalofluoroalkanes toward bromophilic or chlorophilic attacks have been evaluated for the first time by comparing the rates of halophilic attacks by a carbanion derived from the addition of a nucleophile to an olefin with the rate of β-elimination of the same carbanion intermediate. Relative reactivity orders of some polybromofluoroalkanes and polychlorofluoroalkanes are CF_2Br_2>CF_3CFBr_2 ～ CF_2BrCF_2Br>CF_3CBr_3, and CCl_4 > CF_3CCl_3 > CF_2ClCCl_3 > CFCl_3 > CFCl_2CFCl2 ～ CF_2ClCFCl_2. Early transition states for halophilic attacks are speculated.展开更多
It is generally recognized that the formation and accumulation of iron oxides on the surface of zero-valent iron(Fe^(0))resulting in significant decrease of contaminant degradation rates during the long-term reactions...It is generally recognized that the formation and accumulation of iron oxides on the surface of zero-valent iron(Fe^(0))resulting in significant decrease of contaminant degradation rates during the long-term reactions.However,in this study,we found that the removal efficiencies of p-nitrophenol(PNP)by micro zero-valent iron(mFe^(0))could maintain at the satisfactory level in the process of continuous reactions(20 cycles).The removal rate constant(0.1779 min^(-1))of the 5th cycle was 6.74 times higher than that of the 1streaction(0.0264 min^(-1)),even the 20th cycle(0.0371 min^(-1))was higher than that of the 1st reaction.Interestingly,almost no dissolved iron was detected in the solution,and the total iron concentrations decreased dramatically with the process of continuous reactions.The results of scanning electron microscope and energy dispersive spectrometry(SEM-EDS)and X-ray diffraction(XRD)revealed that the structure and composition of corrosion products change from amorphous to highly crystal with the increase of the number of cycles.The corrosion products were mainly magnetite(Fe_(3)O_(4))and a small part of maghemite(γ-Fe_(2)O_(3)),which were in the form of micro sphe res on the surface of mFe^(0).The formation of surface oxidation shell hindered the release of Fe^(2+).X-ray photoelectron spectroscopy(XPS)results illustrated that partial Fe3O_(4) could be converted into y-Fe_(2)O_(3).Electrochemical analysis proved that the electron transfer rate of mFe^(0) increased with the formation of the oxides shell.However,the consumption of iron core and thicker oxide film weakened the electron transfer rate.Besides,the quenching experiments indicated that the reaction activity of mFe^(0) could be enhanced with the addition of scavengers.This study deepened the understanding of the structural transformation and radical production of mFe^(0) in continuous reactions.展开更多
We have generated one possible active site structure of Oxyhemocyanin (Oxy-Hc) and two possible active site structures of Oxytyrosinase (Oxy-Ty) using the EHMO method. Oxy-Hc active site has a plane configuration, whi...We have generated one possible active site structure of Oxyhemocyanin (Oxy-Hc) and two possible active site structures of Oxytyrosinase (Oxy-Ty) using the EHMO method. Oxy-Hc active site has a plane configuration, while Oxy-Ty has boat configuration. When there exist water molecules, two water molecules are connected with the Oxy-Ty active site weakly. Calculations for the reactions of Oxy-Hc and Oxy-Ty (the water-off) with phenol demonstrate that the former reaction is thermodynamically forbidden, while the latter Is realizable.展开更多
Five Shenfu char samples were prepared from Shenfu raw coal at different temperatures （950, 1100, 1200, 1300 and 1400℃） using a muffle furnace. Demineralization of the char samples was performed by treating them wi...Five Shenfu char samples were prepared from Shenfu raw coal at different temperatures （950, 1100, 1200, 1300 and 1400℃） using a muffle furnace. Demineralization of the char samples was performed by treating them with 10% nitric acid for 10 min in a CEM Discover microwave reactor. The gasification of the chars, and corresponding demineralized chars, in a carbon dioxide （CO2） atmosphere was conducted in a Netzsch STA 409Cl31F tempera- ture-programmed thermogravimetry apparatus. The effects of charring temperature and demineralization on the gasification reactivity of chars were systematically investigated. The results show that a char formed at a lower temperature is more reactive except for demineralized char formed at 1100℃, which is less reactive than char formed at 1200℃. Demineralization decreases the char reactivities toward gasification with CO2 to a small extent.展开更多
Considerable efforts have been devoted to characterising the chemical components of vehicle exhaust.However,these components may not accurately reflect the contribution of vehicle exhaust to atmospheric reactivity bec...Considerable efforts have been devoted to characterising the chemical components of vehicle exhaust.However,these components may not accurately reflect the contribution of vehicle exhaust to atmospheric reactivity because of the presence of species not accounted for(“missing species”)given the limitations of analytical instruments.In this study,we improved the laser photolysis–laser-induced fluorescence(LP-LIF)technique and applied it to directly measure the total OH reactivity(TOR)in exhaust gas from light-duty gasoline vehicles in China.The TOR for China Ⅰ to Ⅵ-a vehicles was 15.6,16.3,8.4,2.6,1.5,and 1.6×10^(4) sec^(-1),respectively,reflecting a notable drop as emission standards were upgraded.The TOR was comparable between cold and warm starts.The missing OH reactivity(MOR)values for China Ⅰ to Ⅳ vehicles were close to zero with a cold start but were much higher with a warm start.The variations in oxygenated volatile organic compounds(OVOCs)under different emission standards and for the two start conditions were similar to those of the MOR,indicating that OVOCs and the missing species may have similar production processes.Online measurement revealed that the duration of the stable driving stage was the primary factor leading to the production of OVOCs and missing species.Our findings underscore the importance of direct measurement of TOR from vehicle exhaust and highlight the necessity of adding OVOCs and other organic reactive gases in future upgrades of emission standards,such that the vehicular contribution to atmospheric reactivity can be more effectively controlled.展开更多
Amyloid-β(Aβ)aggregation and metal ion dyshomeostasis are found to be pathological features upon the progress of Alzheimer’s disease(AD).In addition,Aβand metal ions are reported to interact with each other formin...Amyloid-β(Aβ)aggregation and metal ion dyshomeostasis are found to be pathological features upon the progress of Alzheimer’s disease(AD).In addition,Aβand metal ions are reported to interact with each other forming metal–Aβcomplexes,which can affect the aggregation of Aβand cause oxidative stress via the production of reactive oxygen species(ROS).To disrupt metal coordination to Aβand control the reactivities of metal–Aβ,metal chelating agents have been tested.Herein,a series of azamacrocyclic compounds with different properties of Cu(Ⅱ)and Zn(Ⅱ)binding and Aβinteraction were rationally selected under criteria based on structural and functional variations on the backbone of Cyclam.The series contains Cyclam,its N-methylated and cross-bridged(N-methylated or not)analogs,as well as their C-appended hydroxyethyl derivatives,and some of them have been newly synthesized.The reactivities of the cyclam derivatives towards the aggregation of metal–Aβand the generation of ROS mediated by metal–Aβwere evaluated.Their modulative reactivities towards metal–Aβcould be achieved by generat-ing a ternary complex with metal–Aβand chelating the metal ion from metal–Aβ.Moreover,the toxicity induced by metal–Aβin living cells was alleviated by the cyclam derivatives capable of regulating metal–Aβaggregation and metal–Aβ-triggered ROS formation.Overall,our studies illustrate new examples of azamacrocyclic metal chelators that alter the interactions between metal ions and Aβand subsequently modify the reactivities of metal–Aβ,with an indication of how the slight structure–property difference can influence such effects of small molecules.展开更多
Stroke is the leading cause of mortality globally,ultimately leading to severe,lifelong neurological impairments.Patients often suffer from a secondary cascade of damage,including neuroinflammation,cytotoxicity,oxidat...Stroke is the leading cause of mortality globally,ultimately leading to severe,lifelong neurological impairments.Patients often suffer from a secondary cascade of damage,including neuroinflammation,cytotoxicity,oxidative stress,and mitochondrial dysfunction.Regrettably,there is a paucity of clinically available therapeutics to address these issues.Emerging evidence underscores the pivotal roles of astrocytes,the most abundant glial cells in the brain,throughout the various stages of ischemic stroke.In this comprehensive review,we initially provide an overview of the fundamental physiological functions of astrocytes in the brain,emphasizing their critical role in modulating neuronal homeostasis,synaptic activity,and blood-brain barrier integrity.We then delve into the growing body of evidence that highlights the functional diversity and heterogeneity of astrocytes in the context of ischemic stroke.Their well-established contributions to energy provision,metabolic regulation,and neurotransmitter homeostasis,as well as their emerging roles in mitochondrial recovery,neuroinflammation regulation,and oxidative stress modulation following ischemic injury,are discussed in detail.We also explore the cellular and molecular mechanisms underpinning these functions,with particular emphasis on recently identified targets within astrocytes that offer promising prospects for therapeutic intervention.In the final section of this review,we offer a detailed overview of the current therapeutic strategies targeting astrocytes in the treatment of ischemic stroke.These astrocyte-targeting strategies are categorized into traditional small-molecule drugs,microRNAs(miRNAs),stem cell-based therapies,cellular reprogramming,hydrogels,and extracellular vesicles.By summarizing the current understanding of astrocyte functions and therapeutic targeting approaches,we aim to highlight the critical roles of astrocytes during and after stroke,particularly in the pathophysiological development in ischemic stroke.We also emphasize promising avenues for novel,astrocyte-targeted therapeutics that could become clinically available options,ultimately improving outcomes for patients with stroke.展开更多
Activation of neutrophil membrane receptors initiates intracellular signal transduction cascades that orchestrate the cell's effector functions,including phagocytosis,production of reactive oxygen and halogen spec...Activation of neutrophil membrane receptors initiates intracellular signal transduction cascades that orchestrate the cell's effector functions,including phagocytosis,production of reactive oxygen and halogen species,degranulation,and NETosis(formation of neutrophil extracellular traps[NETs]).NETs,which contain antimicrobial compounds such as myeloperoxidase(MPO),represent a strategy to combat infection.However,excessive production of NETs promotes thrombosis,diabetes mellitus,and other diseases.Therefore,investigations into the mechanisms of NETosis and the identification of modulators of this process are critical for developing strategies to address NETosis-related disorders.Here,we identified a novel NETosis inducer,human serum albumin(HSA)modified by the MPO product hypochlorous acid(HSAHOCl),whose accumulation in vivo was correlated with inflammatory processes.Using human blood neutrophils,we investigated HSAHOCl-induced NETosis and detected NET formation by flow cytometry.The results showed that the mechanism of HSAHOClinduced NETosis involved MPO,NADPH oxidase,and phosphatidylinositol 3-kinases(PI3Ks),and that HSAHOCl activated a reactive oxygen species-dependent suicidal type of NETosis.Moreover,HSAHOCl-induced NETosis was inhibited by an anti-HSAHOCl monoclonal antibody.Thus,our findings may facilitate the development of strategies to modulate NETosis in inflammation associated with elevated MPO activity.展开更多
Ischemia–reperfusion injury is a common pathophysiological mechanism in retinal degeneration.PANoptosis is a newly defined integral form of regulated cell death that combines the key features of pyroptosis,apoptosis,...Ischemia–reperfusion injury is a common pathophysiological mechanism in retinal degeneration.PANoptosis is a newly defined integral form of regulated cell death that combines the key features of pyroptosis,apoptosis,and necroptosis.Oligomerization of mitochondrial voltage-dependent anion channel 1 is an important pathological event in regulating cell death in retinal ischemia–reperfusion injury.However,its role in PANoptosis remains largely unknown.In this study,we demonstrated that voltage-dependent anion channel 1 oligomerization-mediated mitochondrial dysfunction was associated with PANoptosis in retinal ischemia–reperfusion injury.Inhibition of voltage-dependent anion channel 1 oligomerization suppressed mitochondrial dysfunction and PANoptosis in retinal cells subjected to ischemia–reperfusion injury.Mechanistically,mitochondria-derived reactive oxygen species played a central role in the voltagedependent anion channel 1-mediated regulation of PANoptosis by promoting PANoptosome assembly.Moreover,inhibiting voltage-dependent anion channel 1 oligomerization protected against PANoptosis in the retinas of rats subjected to ischemia–reperfusion injury.Overall,our findings reveal the critical role of voltage-dependent anion channel 1 oligomerization in regulating PANoptosis in retinal ischemia–reperfusion injury,highlighting voltage-dependent anion channel 1 as a promising therapeutic target.展开更多
Oxygen carriers play a fundamental role in chemical looping combustion(CLC).Iron-based carriers have been extensively investigated owing to their abundance and environmentally friendly.However,the reactivity and separ...Oxygen carriers play a fundamental role in chemical looping combustion(CLC).Iron-based carriers have been extensively investigated owing to their abundance and environmentally friendly.However,the reactivity and separability of iron-based carriers require further enhancement.This study investigates the effect of the concentration of Mn doping on reactivity,elastic properties and magnetic properties based on density functional theory(DFT)calculations.Theoretical results demonstrate that Mn doping effectively enhances reactivity by reducing the oxygen vacancy formation energy(E_(vac))from 2.33 to 0.87 eV.However,Mn doping introduces HV/EV Ms lattice distortions that deteriorate elastic properties,thereby reducing wear resistance,as evidenced by a 54.54%decrease in the hardness-to-Young's modulus ratio(H_(v)/E_(v))forα-Fe_(2)O_(3)and an 83.33%reduction for Fe_(3)O_(4).Furthermore,Mn doping also modifies magnetic properties.The maximum of saturation magnetization(M_(s))of Fe_(3)O_(4)reaches 121.02 emu/g at 33.33%Mn doping concentration.Finally,systematic evaluation identifies 33.33%as the optimal Mn doping concentration,achieving a balance in enhanced reactivity,superior magnetic performance,and retained elastic stability.展开更多
After injury,bone tissue initiates a reparative response to restore its structure and function.The failure to initiate or delay this response could result in fracture nonunion.The molecular mechanisms underlying the o...After injury,bone tissue initiates a reparative response to restore its structure and function.The failure to initiate or delay this response could result in fracture nonunion.The molecular mechanisms underlying the occurrence of fracture nonunion are not yet established.We propose that hypoxia-triggered signaling pathways,mediated by reactive oxygen species(ROS)homeostasis,control Bmp2 expression and fracture healing initiation.The excessive ROS leads to oxidative stress and,ultimately,fracture nonunion.In this study,we silenced Apex1,the final ROS signaling transducer that mediates the activation of key transcription factors by their cysteines oxidoreduction,evaluating its role during endochondral ossification and fracture repair.Silencing Apex1 in limb bud mesenchyme results in transient metaphyseal dysplasia derived from impaired chondrocyte differentiation.During bone regeneration,Apex1 silencing induces a fracture nonunion phenotype,characterized by delayed fracture repair initiation,impaired periosteal response,and reduced chondrocyte and osteoblast differentiation.This compromised chondrocyte differentiation hampers callus vascularization and healing progression.Our findings highlight a critical mechanism where hypoxia-driven ROS signaling in mesenchymal progenitors through APEX1 is essential for fracture healing initiation.展开更多
The reactive materials filled structure(RMFS)is a structural penetrator that replaces high explosive(HE)with reactive materials,presenting a novel self-distributed initiation,multiple deflagrations behavior during pen...The reactive materials filled structure(RMFS)is a structural penetrator that replaces high explosive(HE)with reactive materials,presenting a novel self-distributed initiation,multiple deflagrations behavior during penetrating multi-layered plates,and generating a multipeak overpressure behind the plates.Here analytical models of RMFS self-distributed energy release and equivalent deflagration are developed.The multipeak overpressure formation model based on the single deflagration overpressure expression was promoted.The impact tests of RMFS on multi-layered plates at 584 m/s,616 m/s,and819 m/s were performed to validate the analytical model.Further,the influence of a single overpressure peak and time intervals versus impact velocity is discussed.The analysis results indicate that the deflagration happened within 20.68 mm behind the plate,the initial impact velocity and plate thickness are the crucial factors that dominate the self-distributed multipeak overpressure effect.Three formation patterns of multipeak overpressure are proposed.展开更多
Human health is seriously jeopardized by infections caused by pathogenic microorganisms.The current traditional disinfection technologies have many defects,such as producing harmful by-products,being affected by water...Human health is seriously jeopardized by infections caused by pathogenic microorganisms.The current traditional disinfection technologies have many defects,such as producing harmful by-products,being affected by water turbidity,and high energy consumption.The growing concern for microbial safety has brought non-thermal plasma(NTP)disinfection technology into the spotlight.NTP is a promising disinfection technology with advantages such as environmental protection,safety,room temperature disinfection,short disinfection cycle,and wide applicability.Researchers are continuously optimizing NTP reactions to improve disinfection efficiency.This paper provides an integrated analysis of both plasma disinfection in water and plasma-activated water(PAW)disinfection on object surfaces.NTP can directly treat bacterial contaminated water,and can also be employed to produce PAW as a disinfectant for treating bacteria on surfaces.This review introduces the fundamental concepts and commonly used equipment related to NTP technology,analyzes the influencing factors and mechanisms of disinfection,and concludes by outlining the future directions of NTP technology in the field of disinfection.We hope to provide a reference for the research and practice of bacterial pollution issues.展开更多
Single-atom catalysts for alkyne semi-hydrogenation have been extensively investigated due to their high metal utilization and improved olefin selectivity.However,their reactivity is hindered by the sluggish activatio...Single-atom catalysts for alkyne semi-hydrogenation have been extensively investigated due to their high metal utilization and improved olefin selectivity.However,their reactivity is hindered by the sluggish activation of reactants on isolated sites.Herein,a non-precise metal catalyst consisting of Ni-Cu hetero-diatomic pairs was prepared using a sequential deposition method.The diatomic sites catalyst exhibited an unprecedented activity among non-precious catalysts with over 98%conversion and 77 mol_(C2H2) mol_(metal)^(-1) h^(-1) at 180℃,whereas the single-atom catalysts of Cu/C and Ni/C were almost inert under the same conditions.Experimental and theoretical results revealed the crucial diatomic synergy between the Ni-Cu pairs,wherein acetylene was adsorbed on Ni sites and hydrogen was adsorbed on Cu sites,and the diatomic site enabled spontaneous desorption of ethylene.The superior activity of the diatomic catalyst was observed,resulting from the enhanced dominance of d-electrons of Ni near the Fermi level.The research demonstrates an approach to designing non-precise metal catalysts with extraordinary catalytic performance for alkyne hydrogenation.展开更多
Elaidic acid(EA)is a typical trans fatty acid(TFA)that emerges during the processing of various fatty foods.In this study,we found that EA induced renal injury with necroptosis.Pretreatment with a reactive oxygen spec...Elaidic acid(EA)is a typical trans fatty acid(TFA)that emerges during the processing of various fatty foods.In this study,we found that EA induced renal injury with necroptosis.Pretreatment with a reactive oxygen species(ROS)inhibitor and a RIPK3 inhibitor alleviated EA-induced necroptosis.The data indicated that EA induced renal necroptosis through ROS/RIPK3/MLKL pathway.In mechanistic studies,we explored how EA induced ROS production.Results indicated that EA caused mitochondrial damage by testing MMP,MFN1,VDAC,and FIS1.Further,EA suppressed mitophagy by testing the levels of LC3,p62,PINK1,Parkin,colocalization of LC3 and Mito-Tracker Red.Mitophagy is a process of selective degradation of damaged mitochondria.A large number of damaged mitochondria couldn't be cleared by mitophagy in time,which increased ROS levels in renal cells.Pretreatment with a mitophagy activator decreased EA-induced ROS levels and mitochondrial damage.Taken together,our data identified that EA induced renal necroptosis by destroying mitochondria and inhibiting mitophagy,thereby activating the ROS/RIPK3/MLKL pathway.展开更多
Objective:To investigate the potential of oral probiotics to improve sperm motility and decrease DNA fragmentation in men diagnosed with asthenozoospermia.Methods:Men diagnosed with asthenozoospermia,aged between 18 a...Objective:To investigate the potential of oral probiotics to improve sperm motility and decrease DNA fragmentation in men diagnosed with asthenozoospermia.Methods:Men diagnosed with asthenozoospermia,aged between 18 and 40 years,were randomly assigned to receive probiotic or placebo for 10 weeks.Sperm parameters(count,motility,and morphology)and seminal fluid biochemical markers were assessed using light microscopy and Diff-Quik staining.Intracellular reactive oxygen species levels were measured using the malondialdehyde(MDA)technique,while DNA fragmentation index(DFI)was evaluated through acidic aniline blue staining.Data from both groups were compared to determine the effects of probiotic supplementation.Results:Sixteen men were included.The probiotic group(n=8)showed a significant increase in total sperm motility(P<0.001)and progressive motility(P=0.003)compared to the placebo group(n=8).Additionally,sperm count in the probiotic group was significantly higher than in the placebo group,although other sperm parameters did not show significant changes.Notably,levels of MDA(P=0.027)and DFI(P=0.004)were significantly reduced in the probiotic group,indicating a decrease in oxidative stress and DNA damage.Conclusions:Probiotic supplementation effectively enhances sperm quality by mitigating oxidative stress and reducing DNA damage,thereby improving sperm motility in men with asthenozoospermia.Study registration:The trial was registered with the Iranian Registry of Clinical Trials(IRCT20220119053769N1).展开更多
Knowing the precise relationship between fuel loading and reactivity is essential for guiding reactor criticality extrapolation and online refueling in molten salt reactors(MSRs).This study aims to explore and explain...Knowing the precise relationship between fuel loading and reactivity is essential for guiding reactor criticality extrapolation and online refueling in molten salt reactors(MSRs).This study aims to explore and explain the linear relationship between reactivity and the reciprocal of uranium concentration in thermal-spectrum MSRs.By applying neutron balance theory,we analyzed the neutron absorption cross sections of various nuclides in single-lattice models with varying fuel concentrations.Our findings reveal a simple linear correlation between reactivity and the reciprocal of uranium concentration,which can be explained from the perspective of nuclear reaction cross sections that adhere to the 1/v law in the thermal neutron spectrum.Furthermore,we identified that the neutron absorption single-group cross sections of structural materials and carrier salts exhibit an approximately linear relationship with the fission single-group cross section of ^(235) U;similarly,the reciprocal of ^(235)U’s fission cross section exhibits an approximately linear relationship with uranium concentration.This linear relationship deviates as the volume fraction of molten salt increases,due to a greater proportion of neutrons being captured in the resonance energy spectrum.However,it remains valid for molten salt volume fractions up to 25%and demonstrates broad applicability in the physical design and operation of thermal molten salt reactors.展开更多
Hybrid commutation converters(HCCs)utilizing reverse-blocking integrated gate commutation thyristors(IGCTs)have gained significant attention due to their immunity to commutation failure.Leveraging the recovery enhance...Hybrid commutation converters(HCCs)utilizing reverse-blocking integrated gate commutation thyristors(IGCTs)have gained significant attention due to their immunity to commutation failure.Leveraging the recovery enhancement characteristics of IGCTs,HCCs demonstrate superior performance at reduced extinction angles,thereby minimizing reactive power consumption.This study presents a comprehensive investigation into reactive power control strategies for HCCs operating at small extinction angles.First,the topological configuration and commutation principle of HCC are elucidated.Subsequently,the mechanism of HCC reactive power control is analyzed,and a reactive power control strategy is proposed by combining the converter transformer taps with extinction angles.Moreover,the relationship between transformer taps and reactive power exchange under different rated extinction angles is calculated,and the theoretically rated extinction angle is proposed.Finally,to validate the proposed control strategy,a four-terminal ultra-high voltage direct current power grid incorporating HCC technology is modeled and sim-ulated using PSCAD/EMTDC.The simulation results demonstrate that the proposed strategy effectively supports AC systems by reducing reactive power absorption in HCCs,while simultaneously exhibiting enhanced reli-ability and economic efficiency.展开更多
Overproduction of reactive oxygen species(ROS) following ischemic injury triggers an inflammatory response,significantly impeding neurological functional recovery.Nanozymes with potent antioxidative and anti-inflammat...Overproduction of reactive oxygen species(ROS) following ischemic injury triggers an inflammatory response,significantly impeding neurological functional recovery.Nanozymes with potent antioxidative and anti-inflammatory effects thus offer great potential for ischemic stroke treatment.In this study,we developed an ischemia-homing nanozyme by combining melatonin(MT)-loaded honeycomb manganese dioxide(MnO_(2)) nanoflowers with M2-type microglia membranes to rescue the ischemic penumbra.The surface-engineered M2-type microglia membranes provided intrinsic ischemia-homing and blood-brain barrier(BBB)-crossing properties to the biomimetic nanozymes.This nanozyme can not only transforms harmfulsuperoxide anion radicals(^(·)O^(2-)) and hydrogen peroxide(H_(2)O_(2)) into harmless water and oxygen but also scavenges highly toxic hydroxyl radicals(^(·)OH),dramatically lowering intracellular ROS levels.More importantly,the biomimetic nanoparticles reduce cerebral infarct areas and provide significant neuroprotection against ischemic stroke by lowering oxidative stress,inhibiting cell apoptosis,and decreasing inflammation.This study may offer a viable approach for the use of nanozymes in treating ischemic stroke.展开更多
文摘Relative reactivities of polyhalofluoroalkanes toward bromophilic or chlorophilic attacks have been evaluated for the first time by comparing the rates of halophilic attacks by a carbanion derived from the addition of a nucleophile to an olefin with the rate of β-elimination of the same carbanion intermediate. Relative reactivity orders of some polybromofluoroalkanes and polychlorofluoroalkanes are CF_2Br_2>CF_3CFBr_2 ～ CF_2BrCF_2Br>CF_3CBr_3, and CCl_4 > CF_3CCl_3 > CF_2ClCCl_3 > CFCl_3 > CFCl_2CFCl2 ～ CF_2ClCFCl_2. Early transition states for halophilic attacks are speculated.
基金the financial support from China Postdoctoral Science Foundation(No.2019T120843)Sichuan Science and Technology Program(No.2019YJ0091)。
文摘It is generally recognized that the formation and accumulation of iron oxides on the surface of zero-valent iron(Fe^(0))resulting in significant decrease of contaminant degradation rates during the long-term reactions.However,in this study,we found that the removal efficiencies of p-nitrophenol(PNP)by micro zero-valent iron(mFe^(0))could maintain at the satisfactory level in the process of continuous reactions(20 cycles).The removal rate constant(0.1779 min^(-1))of the 5th cycle was 6.74 times higher than that of the 1streaction(0.0264 min^(-1)),even the 20th cycle(0.0371 min^(-1))was higher than that of the 1st reaction.Interestingly,almost no dissolved iron was detected in the solution,and the total iron concentrations decreased dramatically with the process of continuous reactions.The results of scanning electron microscope and energy dispersive spectrometry(SEM-EDS)and X-ray diffraction(XRD)revealed that the structure and composition of corrosion products change from amorphous to highly crystal with the increase of the number of cycles.The corrosion products were mainly magnetite(Fe_(3)O_(4))and a small part of maghemite(γ-Fe_(2)O_(3)),which were in the form of micro sphe res on the surface of mFe^(0).The formation of surface oxidation shell hindered the release of Fe^(2+).X-ray photoelectron spectroscopy(XPS)results illustrated that partial Fe3O_(4) could be converted into y-Fe_(2)O_(3).Electrochemical analysis proved that the electron transfer rate of mFe^(0) increased with the formation of the oxides shell.However,the consumption of iron core and thicker oxide film weakened the electron transfer rate.Besides,the quenching experiments indicated that the reaction activity of mFe^(0) could be enhanced with the addition of scavengers.This study deepened the understanding of the structural transformation and radical production of mFe^(0) in continuous reactions.
文摘We have generated one possible active site structure of Oxyhemocyanin (Oxy-Hc) and two possible active site structures of Oxytyrosinase (Oxy-Ty) using the EHMO method. Oxy-Hc active site has a plane configuration, while Oxy-Ty has boat configuration. When there exist water molecules, two water molecules are connected with the Oxy-Ty active site weakly. Calculations for the reactions of Oxy-Hc and Oxy-Ty (the water-off) with phenol demonstrate that the former reaction is thermodynamically forbidden, while the latter Is realizable.
基金Projects 2004CB217704 supported by the Special Fund for Major State Basic Research Project, 104031 by the Key Project of Chinese Ministry of Education JHB05-33 by the Program of the Universities in Jiangsu Province for Development of High-Tech Industries
文摘Five Shenfu char samples were prepared from Shenfu raw coal at different temperatures （950, 1100, 1200, 1300 and 1400℃） using a muffle furnace. Demineralization of the char samples was performed by treating them with 10% nitric acid for 10 min in a CEM Discover microwave reactor. The gasification of the chars, and corresponding demineralized chars, in a carbon dioxide （CO2） atmosphere was conducted in a Netzsch STA 409Cl31F tempera- ture-programmed thermogravimetry apparatus. The effects of charring temperature and demineralization on the gasification reactivity of chars were systematically investigated. The results show that a char formed at a lower temperature is more reactive except for demineralized char formed at 1100℃, which is less reactive than char formed at 1200℃. Demineralization decreases the char reactivities toward gasification with CO2 to a small extent.
基金supported by the National Natural Science Foundation of China(Nos.91644221 and 41627809)the National Key Research and Development Program of China(Nos.2016YFC0202201 and 2018YFC0213904)the Key-Area Research and Development Program of Guangdong Province(No.2019B110206001).
文摘Considerable efforts have been devoted to characterising the chemical components of vehicle exhaust.However,these components may not accurately reflect the contribution of vehicle exhaust to atmospheric reactivity because of the presence of species not accounted for(“missing species”)given the limitations of analytical instruments.In this study,we improved the laser photolysis–laser-induced fluorescence(LP-LIF)technique and applied it to directly measure the total OH reactivity(TOR)in exhaust gas from light-duty gasoline vehicles in China.The TOR for China Ⅰ to Ⅵ-a vehicles was 15.6,16.3,8.4,2.6,1.5,and 1.6×10^(4) sec^(-1),respectively,reflecting a notable drop as emission standards were upgraded.The TOR was comparable between cold and warm starts.The missing OH reactivity(MOR)values for China Ⅰ to Ⅳ vehicles were close to zero with a cold start but were much higher with a warm start.The variations in oxygenated volatile organic compounds(OVOCs)under different emission standards and for the two start conditions were similar to those of the MOR,indicating that OVOCs and the missing species may have similar production processes.Online measurement revealed that the duration of the stable driving stage was the primary factor leading to the production of OVOCs and missing species.Our findings underscore the importance of direct measurement of TOR from vehicle exhaust and highlight the necessity of adding OVOCs and other organic reactive gases in future upgrades of emission standards,such that the vehicular contribution to atmospheric reactivity can be more effectively controlled.
基金supported by the National Research Foundation of Korea(NRF)grant funded by the Korean government[NRF-2017R1A2B3002585(to M.H.L.)]the Institute for Basic Science(IBS-R010-D1)in Korea.
文摘Amyloid-β(Aβ)aggregation and metal ion dyshomeostasis are found to be pathological features upon the progress of Alzheimer’s disease(AD).In addition,Aβand metal ions are reported to interact with each other forming metal–Aβcomplexes,which can affect the aggregation of Aβand cause oxidative stress via the production of reactive oxygen species(ROS).To disrupt metal coordination to Aβand control the reactivities of metal–Aβ,metal chelating agents have been tested.Herein,a series of azamacrocyclic compounds with different properties of Cu(Ⅱ)and Zn(Ⅱ)binding and Aβinteraction were rationally selected under criteria based on structural and functional variations on the backbone of Cyclam.The series contains Cyclam,its N-methylated and cross-bridged(N-methylated or not)analogs,as well as their C-appended hydroxyethyl derivatives,and some of them have been newly synthesized.The reactivities of the cyclam derivatives towards the aggregation of metal–Aβand the generation of ROS mediated by metal–Aβwere evaluated.Their modulative reactivities towards metal–Aβcould be achieved by generat-ing a ternary complex with metal–Aβand chelating the metal ion from metal–Aβ.Moreover,the toxicity induced by metal–Aβin living cells was alleviated by the cyclam derivatives capable of regulating metal–Aβaggregation and metal–Aβ-triggered ROS formation.Overall,our studies illustrate new examples of azamacrocyclic metal chelators that alter the interactions between metal ions and Aβand subsequently modify the reactivities of metal–Aβ,with an indication of how the slight structure–property difference can influence such effects of small molecules.
基金supported by the National Natural Science Foundation of China,No.82001325Visiting Scholar Foundation of Shandong Province,No.20236-01(both to CS).
文摘Stroke is the leading cause of mortality globally,ultimately leading to severe,lifelong neurological impairments.Patients often suffer from a secondary cascade of damage,including neuroinflammation,cytotoxicity,oxidative stress,and mitochondrial dysfunction.Regrettably,there is a paucity of clinically available therapeutics to address these issues.Emerging evidence underscores the pivotal roles of astrocytes,the most abundant glial cells in the brain,throughout the various stages of ischemic stroke.In this comprehensive review,we initially provide an overview of the fundamental physiological functions of astrocytes in the brain,emphasizing their critical role in modulating neuronal homeostasis,synaptic activity,and blood-brain barrier integrity.We then delve into the growing body of evidence that highlights the functional diversity and heterogeneity of astrocytes in the context of ischemic stroke.Their well-established contributions to energy provision,metabolic regulation,and neurotransmitter homeostasis,as well as their emerging roles in mitochondrial recovery,neuroinflammation regulation,and oxidative stress modulation following ischemic injury,are discussed in detail.We also explore the cellular and molecular mechanisms underpinning these functions,with particular emphasis on recently identified targets within astrocytes that offer promising prospects for therapeutic intervention.In the final section of this review,we offer a detailed overview of the current therapeutic strategies targeting astrocytes in the treatment of ischemic stroke.These astrocyte-targeting strategies are categorized into traditional small-molecule drugs,microRNAs(miRNAs),stem cell-based therapies,cellular reprogramming,hydrogels,and extracellular vesicles.By summarizing the current understanding of astrocyte functions and therapeutic targeting approaches,we aim to highlight the critical roles of astrocytes during and after stroke,particularly in the pathophysiological development in ischemic stroke.We also emphasize promising avenues for novel,astrocyte-targeted therapeutics that could become clinically available options,ultimately improving outcomes for patients with stroke.
文摘Activation of neutrophil membrane receptors initiates intracellular signal transduction cascades that orchestrate the cell's effector functions,including phagocytosis,production of reactive oxygen and halogen species,degranulation,and NETosis(formation of neutrophil extracellular traps[NETs]).NETs,which contain antimicrobial compounds such as myeloperoxidase(MPO),represent a strategy to combat infection.However,excessive production of NETs promotes thrombosis,diabetes mellitus,and other diseases.Therefore,investigations into the mechanisms of NETosis and the identification of modulators of this process are critical for developing strategies to address NETosis-related disorders.Here,we identified a novel NETosis inducer,human serum albumin(HSA)modified by the MPO product hypochlorous acid(HSAHOCl),whose accumulation in vivo was correlated with inflammatory processes.Using human blood neutrophils,we investigated HSAHOCl-induced NETosis and detected NET formation by flow cytometry.The results showed that the mechanism of HSAHOClinduced NETosis involved MPO,NADPH oxidase,and phosphatidylinositol 3-kinases(PI3Ks),and that HSAHOCl activated a reactive oxygen species-dependent suicidal type of NETosis.Moreover,HSAHOCl-induced NETosis was inhibited by an anti-HSAHOCl monoclonal antibody.Thus,our findings may facilitate the development of strategies to modulate NETosis in inflammation associated with elevated MPO activity.
基金supported by the National Natural Science Foundation of China,Nos.82172196(to KX),82372507(to KX)the Natural Science Foundation of Hunan Province,China,No.2023JJ40804(to QZ)the Key Laboratory of Emergency and Trauma(Hainan Medical University)of the Ministry of Education,China,No.KLET-202210(to QZ)。
文摘Ischemia–reperfusion injury is a common pathophysiological mechanism in retinal degeneration.PANoptosis is a newly defined integral form of regulated cell death that combines the key features of pyroptosis,apoptosis,and necroptosis.Oligomerization of mitochondrial voltage-dependent anion channel 1 is an important pathological event in regulating cell death in retinal ischemia–reperfusion injury.However,its role in PANoptosis remains largely unknown.In this study,we demonstrated that voltage-dependent anion channel 1 oligomerization-mediated mitochondrial dysfunction was associated with PANoptosis in retinal ischemia–reperfusion injury.Inhibition of voltage-dependent anion channel 1 oligomerization suppressed mitochondrial dysfunction and PANoptosis in retinal cells subjected to ischemia–reperfusion injury.Mechanistically,mitochondria-derived reactive oxygen species played a central role in the voltagedependent anion channel 1-mediated regulation of PANoptosis by promoting PANoptosome assembly.Moreover,inhibiting voltage-dependent anion channel 1 oligomerization protected against PANoptosis in the retinas of rats subjected to ischemia–reperfusion injury.Overall,our findings reveal the critical role of voltage-dependent anion channel 1 oligomerization in regulating PANoptosis in retinal ischemia–reperfusion injury,highlighting voltage-dependent anion channel 1 as a promising therapeutic target.
基金Supported by National Natural Science Foundation of China(50976032,51776070)。
文摘Oxygen carriers play a fundamental role in chemical looping combustion(CLC).Iron-based carriers have been extensively investigated owing to their abundance and environmentally friendly.However,the reactivity and separability of iron-based carriers require further enhancement.This study investigates the effect of the concentration of Mn doping on reactivity,elastic properties and magnetic properties based on density functional theory(DFT)calculations.Theoretical results demonstrate that Mn doping effectively enhances reactivity by reducing the oxygen vacancy formation energy(E_(vac))from 2.33 to 0.87 eV.However,Mn doping introduces HV/EV Ms lattice distortions that deteriorate elastic properties,thereby reducing wear resistance,as evidenced by a 54.54%decrease in the hardness-to-Young's modulus ratio(H_(v)/E_(v))forα-Fe_(2)O_(3)and an 83.33%reduction for Fe_(3)O_(4).Furthermore,Mn doping also modifies magnetic properties.The maximum of saturation magnetization(M_(s))of Fe_(3)O_(4)reaches 121.02 emu/g at 33.33%Mn doping concentration.Finally,systematic evaluation identifies 33.33%as the optimal Mn doping concentration,achieving a balance in enhanced reactivity,superior magnetic performance,and retained elastic stability.
基金supported by funds of the Ministerio de Ciencia, Innovación y Universidadesco-financed by European Regional Development Fund-FEDER “A way to make Europe” (Project Ref:PID2023-153309OB-I00) supported by MCIN/AEl/ 10.13039/501100011033/ FEDER, UE+10 种基金Ministerio de Ciencia, Innovación y Universidades through Instituto de Salud Carlos Ⅲ and European Regional Development Funds “A way to make Europe” (PI17/00136, PI20/00076)European Union Horizon 2020 program (grant agreement #874889, HEALIKICK) to F. Granero-MoltóNext Generation EU, Plan de Recuperación, Transformación y Resiliencia RICORS TERAV ISCIII (RD21/0017/0009)H2020-MSCA-RISE-2019 (grant agreement #872648, MEPHOS) to F. Próspersupported by a fellowship from “Asociación de Amigos de la Universidad de Navarra”supported by a fellowship CIMA AC from “Fundación para la Investigación Médica Aplicada”funded by grants PID2022-104776RB-100 and CB16/11/00399 (CIBER CV) from MCIN/AEI/10.13039/501100011033La Caixa Research Health Foundation (Ref. HR23-00084)supported by a fellowship of “Asociación de Amigos de la Universidad de Navarra” and “Obra Social La Caixa”the research leading to these results has received funding from “la Caixa” Banking Foundationsupported by a Sara Borrell grant (CD22/00027) from the Instituto Carlos Ⅲ and Next Generation EU。
文摘After injury,bone tissue initiates a reparative response to restore its structure and function.The failure to initiate or delay this response could result in fracture nonunion.The molecular mechanisms underlying the occurrence of fracture nonunion are not yet established.We propose that hypoxia-triggered signaling pathways,mediated by reactive oxygen species(ROS)homeostasis,control Bmp2 expression and fracture healing initiation.The excessive ROS leads to oxidative stress and,ultimately,fracture nonunion.In this study,we silenced Apex1,the final ROS signaling transducer that mediates the activation of key transcription factors by their cysteines oxidoreduction,evaluating its role during endochondral ossification and fracture repair.Silencing Apex1 in limb bud mesenchyme results in transient metaphyseal dysplasia derived from impaired chondrocyte differentiation.During bone regeneration,Apex1 silencing induces a fracture nonunion phenotype,characterized by delayed fracture repair initiation,impaired periosteal response,and reduced chondrocyte and osteoblast differentiation.This compromised chondrocyte differentiation hampers callus vascularization and healing progression.Our findings highlight a critical mechanism where hypoxia-driven ROS signaling in mesenchymal progenitors through APEX1 is essential for fracture healing initiation.
基金the support received from the National Natural Science Foundation of China(Grant No.12302460)the State Key Laboratory of Explosion Science and Safety Protection(Grant No.YBKT24-02)。
文摘The reactive materials filled structure(RMFS)is a structural penetrator that replaces high explosive(HE)with reactive materials,presenting a novel self-distributed initiation,multiple deflagrations behavior during penetrating multi-layered plates,and generating a multipeak overpressure behind the plates.Here analytical models of RMFS self-distributed energy release and equivalent deflagration are developed.The multipeak overpressure formation model based on the single deflagration overpressure expression was promoted.The impact tests of RMFS on multi-layered plates at 584 m/s,616 m/s,and819 m/s were performed to validate the analytical model.Further,the influence of a single overpressure peak and time intervals versus impact velocity is discussed.The analysis results indicate that the deflagration happened within 20.68 mm behind the plate,the initial impact velocity and plate thickness are the crucial factors that dominate the self-distributed multipeak overpressure effect.Three formation patterns of multipeak overpressure are proposed.
基金support by National Natural Science Foundation of China(No.22006069)Natural Science Foundation of Jiangsu Province in China(No.BK20200801)Jiangsu Special Foundation on Technology Innovation of Carbon Dioxide Peaking and Carbon Neutrality(No.BK20220016).
文摘Human health is seriously jeopardized by infections caused by pathogenic microorganisms.The current traditional disinfection technologies have many defects,such as producing harmful by-products,being affected by water turbidity,and high energy consumption.The growing concern for microbial safety has brought non-thermal plasma(NTP)disinfection technology into the spotlight.NTP is a promising disinfection technology with advantages such as environmental protection,safety,room temperature disinfection,short disinfection cycle,and wide applicability.Researchers are continuously optimizing NTP reactions to improve disinfection efficiency.This paper provides an integrated analysis of both plasma disinfection in water and plasma-activated water(PAW)disinfection on object surfaces.NTP can directly treat bacterial contaminated water,and can also be employed to produce PAW as a disinfectant for treating bacteria on surfaces.This review introduces the fundamental concepts and commonly used equipment related to NTP technology,analyzes the influencing factors and mechanisms of disinfection,and concludes by outlining the future directions of NTP technology in the field of disinfection.We hope to provide a reference for the research and practice of bacterial pollution issues.
基金supported by the National Key R&D Program of China(Grant No.2021YFA1501803)the National Natural Science Foundation of China(NSFC,Grant No.21978148&52206156)。
文摘Single-atom catalysts for alkyne semi-hydrogenation have been extensively investigated due to their high metal utilization and improved olefin selectivity.However,their reactivity is hindered by the sluggish activation of reactants on isolated sites.Herein,a non-precise metal catalyst consisting of Ni-Cu hetero-diatomic pairs was prepared using a sequential deposition method.The diatomic sites catalyst exhibited an unprecedented activity among non-precious catalysts with over 98%conversion and 77 mol_(C2H2) mol_(metal)^(-1) h^(-1) at 180℃,whereas the single-atom catalysts of Cu/C and Ni/C were almost inert under the same conditions.Experimental and theoretical results revealed the crucial diatomic synergy between the Ni-Cu pairs,wherein acetylene was adsorbed on Ni sites and hydrogen was adsorbed on Cu sites,and the diatomic site enabled spontaneous desorption of ethylene.The superior activity of the diatomic catalyst was observed,resulting from the enhanced dominance of d-electrons of Ni near the Fermi level.The research demonstrates an approach to designing non-precise metal catalysts with extraordinary catalytic performance for alkyne hydrogenation.
基金supported by National Key Research and Development Program of China(2023YFD1800902).
文摘Elaidic acid(EA)is a typical trans fatty acid(TFA)that emerges during the processing of various fatty foods.In this study,we found that EA induced renal injury with necroptosis.Pretreatment with a reactive oxygen species(ROS)inhibitor and a RIPK3 inhibitor alleviated EA-induced necroptosis.The data indicated that EA induced renal necroptosis through ROS/RIPK3/MLKL pathway.In mechanistic studies,we explored how EA induced ROS production.Results indicated that EA caused mitochondrial damage by testing MMP,MFN1,VDAC,and FIS1.Further,EA suppressed mitophagy by testing the levels of LC3,p62,PINK1,Parkin,colocalization of LC3 and Mito-Tracker Red.Mitophagy is a process of selective degradation of damaged mitochondria.A large number of damaged mitochondria couldn't be cleared by mitophagy in time,which increased ROS levels in renal cells.Pretreatment with a mitophagy activator decreased EA-induced ROS levels and mitochondrial damage.Taken together,our data identified that EA induced renal necroptosis by destroying mitochondria and inhibiting mitophagy,thereby activating the ROS/RIPK3/MLKL pathway.
基金supported by Kashan University of Medical Science,Kashan,Iran(Grant No.40001).
文摘Objective:To investigate the potential of oral probiotics to improve sperm motility and decrease DNA fragmentation in men diagnosed with asthenozoospermia.Methods:Men diagnosed with asthenozoospermia,aged between 18 and 40 years,were randomly assigned to receive probiotic or placebo for 10 weeks.Sperm parameters(count,motility,and morphology)and seminal fluid biochemical markers were assessed using light microscopy and Diff-Quik staining.Intracellular reactive oxygen species levels were measured using the malondialdehyde(MDA)technique,while DNA fragmentation index(DFI)was evaluated through acidic aniline blue staining.Data from both groups were compared to determine the effects of probiotic supplementation.Results:Sixteen men were included.The probiotic group(n=8)showed a significant increase in total sperm motility(P<0.001)and progressive motility(P=0.003)compared to the placebo group(n=8).Additionally,sperm count in the probiotic group was significantly higher than in the placebo group,although other sperm parameters did not show significant changes.Notably,levels of MDA(P=0.027)and DFI(P=0.004)were significantly reduced in the probiotic group,indicating a decrease in oxidative stress and DNA damage.Conclusions:Probiotic supplementation effectively enhances sperm quality by mitigating oxidative stress and reducing DNA damage,thereby improving sperm motility in men with asthenozoospermia.Study registration:The trial was registered with the Iranian Registry of Clinical Trials(IRCT20220119053769N1).
基金supported by the Youth Innovation Promotion Association of the Chinese Academy of Sciences(No.2020261)the Strategic Priority Research Program of the Chinese Academy of Sciences(No.XDA02010000)the Young Potential Program of the Shanghai Institute of Applied Physics,Chinese Academy of Sciences(No.SINAP-YXJH-202412)。
文摘Knowing the precise relationship between fuel loading and reactivity is essential for guiding reactor criticality extrapolation and online refueling in molten salt reactors(MSRs).This study aims to explore and explain the linear relationship between reactivity and the reciprocal of uranium concentration in thermal-spectrum MSRs.By applying neutron balance theory,we analyzed the neutron absorption cross sections of various nuclides in single-lattice models with varying fuel concentrations.Our findings reveal a simple linear correlation between reactivity and the reciprocal of uranium concentration,which can be explained from the perspective of nuclear reaction cross sections that adhere to the 1/v law in the thermal neutron spectrum.Furthermore,we identified that the neutron absorption single-group cross sections of structural materials and carrier salts exhibit an approximately linear relationship with the fission single-group cross section of ^(235) U;similarly,the reciprocal of ^(235)U’s fission cross section exhibits an approximately linear relationship with uranium concentration.This linear relationship deviates as the volume fraction of molten salt increases,due to a greater proportion of neutrons being captured in the resonance energy spectrum.However,it remains valid for molten salt volume fractions up to 25%and demonstrates broad applicability in the physical design and operation of thermal molten salt reactors.
文摘Hybrid commutation converters(HCCs)utilizing reverse-blocking integrated gate commutation thyristors(IGCTs)have gained significant attention due to their immunity to commutation failure.Leveraging the recovery enhancement characteristics of IGCTs,HCCs demonstrate superior performance at reduced extinction angles,thereby minimizing reactive power consumption.This study presents a comprehensive investigation into reactive power control strategies for HCCs operating at small extinction angles.First,the topological configuration and commutation principle of HCC are elucidated.Subsequently,the mechanism of HCC reactive power control is analyzed,and a reactive power control strategy is proposed by combining the converter transformer taps with extinction angles.Moreover,the relationship between transformer taps and reactive power exchange under different rated extinction angles is calculated,and the theoretically rated extinction angle is proposed.Finally,to validate the proposed control strategy,a four-terminal ultra-high voltage direct current power grid incorporating HCC technology is modeled and sim-ulated using PSCAD/EMTDC.The simulation results demonstrate that the proposed strategy effectively supports AC systems by reducing reactive power absorption in HCCs,while simultaneously exhibiting enhanced reli-ability and economic efficiency.
基金supported by National Key R&D Program of China (No.2022YFC3501700)National Natural Science Foundation of China (No.82274059)+3 种基金Naval Military Medical University,Far East Talent Project (No.SL-33)Talent Project established by Chinese Pharmaceutical Association Hospital Pharmacy department (No.CPA-Z05-ZC-2024-003)Shanghai Oriental Talent Plan Youth Program (formerly Shanghai Young Top-Notch Talent) (2023)the Baoshan District Medical Key Science (Specialty) and Specialty Brand Construction Project (No.BSZK-2023-A12)。
文摘Overproduction of reactive oxygen species(ROS) following ischemic injury triggers an inflammatory response,significantly impeding neurological functional recovery.Nanozymes with potent antioxidative and anti-inflammatory effects thus offer great potential for ischemic stroke treatment.In this study,we developed an ischemia-homing nanozyme by combining melatonin(MT)-loaded honeycomb manganese dioxide(MnO_(2)) nanoflowers with M2-type microglia membranes to rescue the ischemic penumbra.The surface-engineered M2-type microglia membranes provided intrinsic ischemia-homing and blood-brain barrier(BBB)-crossing properties to the biomimetic nanozymes.This nanozyme can not only transforms harmfulsuperoxide anion radicals(^(·)O^(2-)) and hydrogen peroxide(H_(2)O_(2)) into harmless water and oxygen but also scavenges highly toxic hydroxyl radicals(^(·)OH),dramatically lowering intracellular ROS levels.More importantly,the biomimetic nanoparticles reduce cerebral infarct areas and provide significant neuroprotection against ischemic stroke by lowering oxidative stress,inhibiting cell apoptosis,and decreasing inflammation.This study may offer a viable approach for the use of nanozymes in treating ischemic stroke.
