The oxygen evolution reaction(OER)serves as a fundamental half–reaction in the electrolysis of water for hydrogen production,which is restricted by the sluggish OER reaction kinetics and unable to be practically appl...The oxygen evolution reaction(OER)serves as a fundamental half–reaction in the electrolysis of water for hydrogen production,which is restricted by the sluggish OER reaction kinetics and unable to be practically applied.The traditional lattice oxygen oxidation mechanism(LOM)offers an advantageous route by circumventing the formation of M-OOH^(*)in the adsorption evolution mechanism(AEM),thus enhancing the reaction kinetics of the OER but resulting in possible structural destabilization due to the decreased M–O bond order.Fortunately,the asymmetry of tetrahedral and octahedral sites in transition metal spinel oxides permits the existence of non-bonding oxygen,which could be activated by rational band structure design for direct O-O coupling,where the M–O bond maintains its initial bond order.Here,non-bonding oxygen was introduced into NiFe_(2)O_(4)via annealing in an oxygen-deficient atmosphere.Then,in-situ grown sulfate species on octahedral nickel sites significantly improved the reactivity of the non-bonding oxygen electrons,thereby facilitating the transformation of the redox center from metal to oxygen.LOM based on non-bonding oxygen(LOMNB)was successfully activated within NiFe_(2)O_(4),exhibiting a low overpotential of 206 mV to achieve a current density of 10 mA cm^(-2)and excellent durability of stable operation for over 150 h.Additionally,catalysts featuring varying band structures were synthesized for comparative analysis,and it was found that the reversible redox processes of non-bonding oxygen and the accumulation of non-bonding oxygen species containing 2p holes are critical prerequisites for triggering and sustaining the LOMNB pathway in transition metal spinel oxides.These findings may provide valuable insights for the future development of spinel-oxide-based LOM catalysts.展开更多
Water electrolysis,a process for producing green hydrogen from renewable energy,plays a crucial role in the transition toward a sustainable energy landscape and the realization of the hydrogen economy.Oxygen evolution...Water electrolysis,a process for producing green hydrogen from renewable energy,plays a crucial role in the transition toward a sustainable energy landscape and the realization of the hydrogen economy.Oxygen evolution reaction(OER)is a critical step in water electrolysis and is often limited by its slow kinetics.Two main mechanisms,namely the adsorbate evolution mechanism(AEM)and lattice oxygen oxidation mechanism(LOM),are commonly considered in the context of OER.However,designing efficient catalysts based on either the AEM or the LOM remains a topic of debate,and there is no consensus on whether activity and stability are directly related to a certain mechanism.Considering the above,we discuss the characteristics,advantages,and disadvantages of AEM and LOM.Additionally,we provide insights on leveraging the LOM to develop highly active and stable OER catalysts in future.For instance,it is essential to accurately differentiate between reversible and irreversible lattice oxygen redox reactions to elucidate the LOM.Furthermore,we discuss strategies for effectively activating lattice oxygen to achieve controllable steady-state exchange between lattice oxygen and an electrolyte(OH^(-)or H_(2)O).Additionally,we discuss the use of in situ characterization techniques and theoretical calculations as promising avenues for further elucidating the LOM.展开更多
Selective oxidation of propane by lattice oxygen of vanadium-phosphorus oxide(VPO) catalysts was investigated with a pulse reactor in which the oxidation of propane and there-oxidation of catalyst were implemented alt...Selective oxidation of propane by lattice oxygen of vanadium-phosphorus oxide(VPO) catalysts was investigated with a pulse reactor in which the oxidation of propane and there-oxidation of catalyst were implemented alternately in the presence of water vapor. The principalproducts are acrylic acid (AA), acetic acid (HAc), and carbon oxides. In addition, small amounts ofC_1 and C_2 hydrocarbons were also found, molar ratio of AA to HAc is 1.4-2.2. The active oxygenspecies are those adsorbed on catalyst surface firmly and/or bound to catalyst lattice, i.e. latticeoxygen; the selective oxidation of propane on VPO catalysts can be carried out in a circulatingfluidized bed (CFB) riser reactor. For propane oxidation over VPO catalysts, the effects of reactiontemperature in a pulse reactor were found almost the same as in a steady-state flow reactor. Thatis, as the reaction temperature increases, propane conversion and the amount of C_1+C_2 hydrocarbonsin the product increase steadily, while selectivity to acrylic acid and to acetic acid increaseprior to 350℃ then begin to drop at temperatures higher than 350℃, and yields of acrylic acid andof acetic acid attained maximum at about 400℃. The maximum yields of acrylic acid and of aceticacid for a single-pass are 7.50% and 4.59% respectively, with 38.2% propane conversion. When theamount of propane pulsed decreases or the amount of catalyst loaded increases, the conversionincreases but the selectivity decreases. Increasing the flow rate of carrier gases causes theconversion pass through a minimum but selectivity and yields pass through a maximum. In a fixed bedreactor, it is hard to obtain high selectivity at a high reaction conversion due to the furtherdegradation of acrylic acid and acetic acid even though propane was oxidized by the lattice oxygen.The catalytic performance can be improved in the presence of excess propane. Propylene can beoxidized by lattice oxygen of VPO catalyst at 250℃, nevertheless, selectivity to AA and to HAc areeven lower, much more acetic acid was produced (molar ratio of AA to HAc is 0.19:1-0.83:1) thoughthe oxidation products are the same as from propane.展开更多
Transition metal chalcogenides(TMCs)are recognized as pre-catalysts,and their(oxy)hydroxides derived from electrochemical reconstruction are the active species in the water oxidation.However,understanding the role of ...Transition metal chalcogenides(TMCs)are recognized as pre-catalysts,and their(oxy)hydroxides derived from electrochemical reconstruction are the active species in the water oxidation.However,understanding the role of the residual chalcogen in the reconstructed layer is lacking in detail,and the corresponding catalytic mechanism remains controversial.Here,taking Cu_(1-x)Co_(x)S as a platform,we explore the regulating effect and existence form of the residual S doped into the reconstructive layer for oxygen evolution reaction(OER),where a dual-path OER mechanism is proposed.First-principles calculations and operando~(18)O isotopic labeling experiments jointly reveal that the residual S in the reconstructive layer of Cu_(1-x)Co_(x)S can wisely balance the adsorbate evolution mechanism(AEM)and lattice oxygen oxidation mechanism(LOM)by activating lattice oxygen and optimizing the adsorption/desorption behaviors at metal active sites,rather than change the reaction mechanism from AEM to LOM.Following such a dual-path OER mechanism,Cu_(0.4)Co_(0.6)S-derived Cu_(0.4)Co_(0.6)OSH not only overcomes the restriction of linear scaling relationship in AEM,but also avoids the structural collapse caused by lattice oxygen migration in LOM,so as to greatly reduce the OER potential and improved stability.展开更多
In recent decade, Au nanoclusters of atomic precision （AunLm, where L= organic ligand： thiolate andphosphine） have been shown as a new promising nanogold catalyst. The well-defined AunLm catalystspossess unique ele...In recent decade, Au nanoclusters of atomic precision （AunLm, where L= organic ligand： thiolate andphosphine） have been shown as a new promising nanogold catalyst. The well-defined AunLm catalystspossess unique electronic properties and frameworks, providing an excellent opportunity to correlate theintrinsic catalytic behavior with the cluster＇s framework as well as to study the catalytic mechanismsover gold nanoclusters. In this review, we only demonstrate the important roles of the gold nanoclustersin the oxygen activation （e.g., 302 to 102） and their selective oxidations in the presence of oxygen （e.g., COto C02, sulfides to sulfoxides, alcohol to aldehyde, styrene to styrene epoxide, amines to imines, andglucose to gluconic acid）. The size-specificity （Au25 （1.3 nm）, Au38 （].5 nm）, Au144 （1.9 nm）, etc.）, ligandengineering （e.g., aromatic vs aliphatic）, and doping effects （e.g., copper, silver, palladium, and platinum）are discussed in details. Finally, the proposed reactions＇ mechanism and the relationships of clusters＇structure and activity at the atomic level also are presented.展开更多
This study was focused on the influence of active oxygen on the performance of Pt/CeO2 catalysts for CO oxidation. A series of CeO2 supports with different contents of active oxygen were obtained by adding surfactant ...This study was focused on the influence of active oxygen on the performance of Pt/CeO2 catalysts for CO oxidation. A series of CeO2 supports with different contents of active oxygen were obtained by adding surfactant at different synthesis steps. 0.25 wt% Pt was loaded on these CeO2 supports by incipientwetness impregnation methods. The catalysts were characterized by N2 adsorption, X-ray diffraction（XRD）, high-resolution transmission electron microscopy（HRTEM）, H2 temperature-programmed reduction（H2-TPR）, dynamic oxygen storage capacity（DOSC） and in-situ DRIFTS technologies. For S-f supports, the surfactant was added into the solution before spray-drying in the synthesis process, which facilitates more active oxygen formation on the surface of CeO2. After loading Pt, the more active oxygen on CeO2 contributes to dispersing Pt species and enhancing the CO oxidation activity. As for the aged samples,Pt-R-h shows the highest activity above 190 ℃ because of the presence of more partly oxidized Pt^（δ＋） species. Thus the activity is also influenced by the states of Pt and the Pt^（δ＋） species may contribute to the high activity at elevated temperature.展开更多
Kinetics of oxygen adsorption on single crystal Mn<sub>5</sub>Si<sub>3</sub> （111） surface and initial surface oxidation were investigated. Oxygen chemisorbs dissociatively at room temperatur...Kinetics of oxygen adsorption on single crystal Mn<sub>5</sub>Si<sub>3</sub> （111） surface and initial surface oxidation were investigated. Oxygen chemisorbs dissociatively at room temperature on Mn and Si atoms. A fast oxidation of Si atoms occurs followed by oxidation of Mn atoms at RT. The MnO<sub>2</sub> was reduced by Si atoms and the SiO was oxidized further to SiO<sub>2</sub> during the sample heating.展开更多
The oxidizing behavior of Si-containing steel was investigated in an O2 and N2 binary-component gas with oxygen contents ranging between 0.5 vol% and 4.0 vol% under anisothermal-oxidation conditions. A simultaneous th...The oxidizing behavior of Si-containing steel was investigated in an O2 and N2 binary-component gas with oxygen contents ranging between 0.5 vol% and 4.0 vol% under anisothermal-oxidation conditions. A simultaneous thermal analyzer was employed to simulate the heating process of Si-containing steel in industrial reheating furnaces. The oxidation gas mixtures were introduced from the commencement of heating. The results show that the oxidizing rate remains constant in the isothermal holding process at high temperatures; therefore, the mass change versus time presents a linear law. A linear relation also exists between the oxidizing rate and the oxygen content. Using the linear regression equation, the oxidation rate at different oxygen contents can be predicted. In addition, the relationship between the total mass gain and the oxygen content is linear; thus, the total mass gain at oxygen contents between 0.5 vol%–4.0 vol% can be determined. These results enrich the theoretical studies of the oxidation process in Si-containing steels.展开更多
With the objectives of enhancing the stability,optical properties and visible-light photocatalytic activity of photocatalysts,we modified oxygen vacancy-rich zinc oxide（Vo-ZnO） with graphitic carbon nitride（g-C3N4...With the objectives of enhancing the stability,optical properties and visible-light photocatalytic activity of photocatalysts,we modified oxygen vacancy-rich zinc oxide（Vo-ZnO） with graphitic carbon nitride（g-C3N4）. The resulting g-C3N4/Vo-ZnO hybrid photocatalysts showed higher visible-light photocatalytic activity than pure Vo-ZnO and g-C3N4. The hybrid photocatalyst with a g-C3N4 content of 1 wt% exhibited the highest photocatalytic degradation activity under visible-light irradiation（λ≥ 400 nm）. In addition,the g-C3N4/Vo-ZnO photocatalyst was not deactivated after five cycles of methyl orange degradation,indicating that it is stable under light irradiation. Finally,a Z-scheme mechanism for the enhanced photocatalytic activity and stability of the g-C3N4/Vo-ZnO hybrid photocatalyst was proposed. The fast charge separation and transport within the g-C3N4/Vo-ZnO hybrid photocatalyst were attributed as the origins of its enhanced photocatalytic performance.展开更多
The oxygen evolution reaction(OER)is the essential module in energy conversion and storage devices such as electrolyzer,rechargeable metal–air batteries and regenerative fuel cells.The adsorption energy scaling relat...The oxygen evolution reaction(OER)is the essential module in energy conversion and storage devices such as electrolyzer,rechargeable metal–air batteries and regenerative fuel cells.The adsorption energy scaling relations between the reaction intermediates,however,impose a large intrinsic overpotential and sluggish reaction kinetics on OER catalysts.Developing advanced electrocatalysts with high activity and stability based on non-noble metal materials is still a grand challenge.Central to the rational design of novel and high-efficiency catalysts is the development and understanding of quantitative structure–activity relationships,which correlate the catalytic activities with structural and electronic descriptors.This paper comprehensively reviews the benchmark descriptors for OER electrolysis,aiming to give an in-depth understanding on the origins of the electrocatalytic activity of the OER and further contribute to building the theory of electrocatalysis.Meanwhile,the cutting-edge research frontiers for proposing new OER paradigms and crucial strategies to circumvent the scaling relationship are also summarized.Challenges,opportunities and perspectives are discussed,intending to shed some light on the rational design concepts and advance the development of more efficient catalysts for enhancing OER performance.展开更多
The lattice oxygen oxidation mechanism(LOM)provides an efficient pathway for accelerating the oxygen evolution reaction(OER)in certain electrocatalysts by activating and involving lattice oxygen in the catalytic OER p...The lattice oxygen oxidation mechanism(LOM)provides an efficient pathway for accelerating the oxygen evolution reaction(OER)in certain electrocatalysts by activating and involving lattice oxygen in the catalytic OER process.We investigated the potential of disordered rocksalts as catalysts for accelerating the OER through the LOM process,leveraging their unique metastable Li-O-Li bond states.Theoretical calculations were employed to predict the catalytic pathways and activities of disordered rocksalts(DRX),such as Li_(1.2)Co_(0.4)Ti_(0.5)O_(2)(LCTO).The results revealed that benefiting from the unhybridized Li-O electronic orbitals and the resulting metastable states of Li-O-Li bonds in DRX,LCTO exhibited a typical LOM pathway,and the lattice oxygen was easily activated and participated in the OER.The experimental results showed that LCTO exhibited a remarkable pH-dependent OER activity through the LOM pathway,with an overpotential of 241 mV at a current density of 10 mA/cm^(2),and excellent long-term stability.This work provides a novel chemical space for designing highly active and stable OER electrocatalysts by leveraging the LOM reaction pathway.展开更多
Selective oxidation of saturated hydrocarbons with molecular oxygen has been of great interest in catalysis, and the development of highly efficient catalysts for this process is a crucial challenge. A new kind of het...Selective oxidation of saturated hydrocarbons with molecular oxygen has been of great interest in catalysis, and the development of highly efficient catalysts for this process is a crucial challenge. A new kind of heterogeneous catalyst, cobalt-doped carbon nitride polymer(g-C_3N_4),was harnessed for the selective oxidation of cyclohexane. X-ray diffraction, Fourier transform infrared spectra and high resolution transmission electron microscope revealed that Co species were highly dispersed in g-C_3N_4 matrix and the characteristic structure of polymeric g-C_3N_4 can be retained after Co-doping, although Co-doping caused the incomplete polymerization to some extent. Ultraviolet-visible, Raman and X-ray photoelectron spectroscopy further proved the successful Co doping in g-C_3N_4 matrix as the form of Co(Ⅱ)-N bonds. For the selective oxidation of cyclohexane, Co-doping can markedly promote the catalytic performance of g-C_3N_4 catalyst due to the synergistic effect of Co species and gC_3N_4 hybrid. Furthermore, the content of Co largely affected the activity of Co-doped g-C_3N_4 catalysts, among which the catalyst with 9.0 wt%Co content exhibited the highest yield(9.0%) of cyclohexanone and cyclohexanol, as well as a high stability. Meanwhile, the reaction mechanism over Co-doped g-C_3N_4 catalysts was elaborated.展开更多
In this work, the influence of trivalent rare-earth dopants（Sm and La） on the structure-activity properties of CeO2 was thoroughly studied for diesel soot oxidation. For this, an optimized 40% of Sm and La was incor...In this work, the influence of trivalent rare-earth dopants（Sm and La） on the structure-activity properties of CeO2 was thoroughly studied for diesel soot oxidation. For this, an optimized 40% of Sm and La was incorporated into the CeO2 using a facile coprecipitation method from ultra-high dilute aqueous solutions. A systematic physicochemical characterization was carried out using X-ray diffraction（XRD）, transmission electron microscopy（TEM）, Brumauer-Emmett-teller method（BET） surface area, X-ray photoelectron spectroscopy（XPS）, Raman, and H2-temperature programmed reduction（TPR） techniques. The soot oxidation efficiency of the catalysts was investigated using a thermogravimetric method. The XRD results suggested the formation of nanocrystalline single phase CeO2-Sm2O3 and CeO2-La2O3 solid solutions. The Sm- and La-doped CeO2 materials exhibited smaller crystallite size and higher BET surface area compared with the pure CeO2. Owing to the difference in the oxidation states of the dopants（Sm3＋ and La3＋） and the Ce4＋, a number of oxygen vacancies were generated in CeO2-Sm2O3 and CeO2-La2O3 samples. The H2-TPR studies evidenced the improved reducible nature of the CeO2-Sm2O3 and CeO2-La2O3 samples compared with the CeO2. It was found that the addition of Sm and La to the CeO2 outstandingly enhanced its catalytic efficiency for the oxidation of diesel soot. The observed 50% soot conversion temperatures for the CeO2-Sm2O3, CeO2-La2O3 and CeO2 were ~790, 843 and 864 K（loose contact）, respectively, and similar activity order was also found under the tight contact condition. The high soot oxidation efficacy of the CeO2-Sm2O3 sample was attributed to numerous catalytically favourable properties, like smaller crystallite size, larger surface area, abundant oxygen vacancies, and superior reducible nature.展开更多
Postoperative cognitive dysfunction is a crucial public health issue that has been increasingly studied in efforts to reduce symptoms or prevent its occurrence. However, effective advances remain lacking. Hyperbaric o...Postoperative cognitive dysfunction is a crucial public health issue that has been increasingly studied in efforts to reduce symptoms or prevent its occurrence. However, effective advances remain lacking. Hyperbaric oxygen preconditioning has proved to protect vital organs, such as the heart, liver, and brain. Recently, it has been introduced and widely studied in the prevention of postoperative cognitive dysfunction, with promising results. However, the neuroprotective mechanisms underlying this phenomenon remain controversial. This review summarizes and highlights the definition and application of hyperbaric oxygen preconditioning, the perniciousness and pathogenetic mechanism underlying postoperative cognitive dysfunction, and the effects that hyperbaric oxygen preconditioning has on postoperative cognitive dysfunction. Finally, we conclude that hyperbaric oxygen preconditioning is an effective and feasible method to prevent, alleviate, and improve postoperative cognitive dysfunction, and that its mechanism of action is very complex, involving the stimulation of endogenous antioxidant and anti-inflammation defense systems.展开更多
An efficient and convenient tert-butyl nitrite-catalyzed selective aerobic oxidation of thiols has been developed. Under the optimal reaction conditions, a number of thiol derivatives including aromatic thiols, hetero...An efficient and convenient tert-butyl nitrite-catalyzed selective aerobic oxidation of thiols has been developed. Under the optimal reaction conditions, a number of thiol derivatives including aromatic thiols, heteroaromatic thiols and aliphatic thiols can be converted into their corresponding disulfides in good to excellent yields.展开更多
Economic concentrations of Fe–Ti oxides occurring as massive layers in the middle and upper parts of the Hongge intrusion are different from other layered intrusions(Panzhihua and Baima) in the Emeishan large igneous...Economic concentrations of Fe–Ti oxides occurring as massive layers in the middle and upper parts of the Hongge intrusion are different from other layered intrusions(Panzhihua and Baima) in the Emeishan large igneous province, SW China. This paper reports on the new mineral compositions of magnetite and ilmenite for selected cumulate rocks and clinopyroxene and plagioclase for basalts. We use these data to estimate the oxidation state of parental magmas and during ore formation to constrain the factors leading to the abundant accumulation of Fe–Ti oxides involved with the Hongge layered intrusion. The results show that the oxygen fugacities of parental magma are in the range of FMQ-1.56 to FMQ+0.14, and the oxygen fugacities during the ore formation of the Fe–Ti oxides located in the lower olivine clinopyroxenite zone(LOZ) and the middle clinopyroxenite zone(MCZ) of the Hongge intrusion are in the range of FMQ-1.29 to FMQ-0.2 and FMQ-0.49 to FMQ+0.82, respectively.The MELTS model demonstrates that, as the oxygen fugacity increases from the FMQ-1 to FMQ+1, the proportion of crystallization magnetite increases from 11 % to 16 % and the crystallization temperature of the Fe–Ti oxides advances from 1134 to 1164 °C. The moderate oxygen fugacities for the Hongge MCZ indicate that the oxygen fugacity was not the only factor affecting the crystallization of Fe–Ti oxides. We speculated that theinitial anhydrous magma that arrived at the Hongge shallow magma chamber became hydrous by attracting the H_2O of the strata. In combination with increasing oxygen fugacities from the LOZ(FMQ-1.29 to FMQ-0.2) to the MCZ(FMQ-0.49 to FMQ+0.82), these two factors probably account for the large-scale Fe–Ti oxide ore layers in the MCZ of the Hongge intrusion.展开更多
Pd@Zr/Ce O2 core-shell catalyst prepared by hydrothermal method was applied in CO oxidation reaction, exhibiting high CO oxidation activity at low temperature.XRD（X-ray diffraction） analysis demonstrated that the re...Pd@Zr/Ce O2 core-shell catalyst prepared by hydrothermal method was applied in CO oxidation reaction, exhibiting high CO oxidation activity at low temperature.XRD（X-ray diffraction） analysis demonstrated that the remarkable enhancement of catalytic performance was found to depend on the presence of more oxygen vacancies in the core-shell structure, which contributed higher content of and ready release of active oxygen species at low temperature, confirmed by H2-TPR（temperature programed reduction） results.Interestingly, introducing a small amount of zirconium（0.5 wt.%） exhibited a significant improvement of catalytic activity because the introduction of Zr further improved the amount of crystal defects and promoted the migration of oxygen species.展开更多
We describe here a one-step method for the synthesis of Au/TiO2 nanosphere materials,which were formed by layered deposition of multiple anatase TiO2 nanosheets.The Au nanoparticles were stabilized by structural defec...We describe here a one-step method for the synthesis of Au/TiO2 nanosphere materials,which were formed by layered deposition of multiple anatase TiO2 nanosheets.The Au nanoparticles were stabilized by structural defects in each TiO2 nanosheet,including crystal steps and edges,thereby fixing the Au-TiO2 perimeter interface.Reactant transfer occurred along the gaps between these TiO2 nanosheet layers and in contact with catalytically active sites at the Au-TiO2 interface.The doped Au induced the formation of oxygen vacancies in the Au-TiO2 interface.Such vacancies are essential for generating active oxygen species（-＊O^-） on the TiO2 surface and Ti^3＋ ions in bulk TiO2.These ions can then form Ti^3＋-O^--Ti^4＋species,which are known to enhance the catalytic activity of formaldehyde（HCHO） oxidation.These studies on structural and oxygen vacancy defects in Au/TiO2 samples provide a theoretical foundation for the catalytic mechanism of HCHO oxidation on oxide-supported Au materials.展开更多
The functionalization of multi-walled carbon nanotubes （MWCNTs） by ozone treatment has been sys- tematically investigated by using Raman spectroscopy, transmission electron microscopy （TEM）, Fourier transform inha...The functionalization of multi-walled carbon nanotubes （MWCNTs） by ozone treatment has been sys- tematically investigated by using Raman spectroscopy, transmission electron microscopy （TEM）, Fourier transform inhared spectroscopy （FTIR）, X-ray photoelectron spectroscopy （XPS）, organic elemental anal- ysis （OEA） and Boehm titration. The results showed that the functionalization process occurred at defective sites （opened mouths, tube caps, debris, etc.） before opening caps and truncating walls, and finally the graphitic structure was deteriorated. The surface oxygen content first increased with the treatment time but kept at around 8.0 wt% after 5 h. The analysis of the distribution of oxygen-containing groups re- vealed that phenolic hydroxyl was gradually converted to carboxyl and lactone, The carboxyl was found to play a pivotal role to reduce the over-potentials when we used the functionalized MWCNTs as the cat- alyst for oxygen reduction reaction （ORR）.展开更多
Objective: To observe the effect of acupuncture on blood oxygen free radical (OFR) and nitric oxide (NO) levels in the treatment of apoplectic sequelae. Methods: A total of 61 cases of apoplectic patients were subject...Objective: To observe the effect of acupuncture on blood oxygen free radical (OFR) and nitric oxide (NO) levels in the treatment of apoplectic sequelae. Methods: A total of 61 cases of apoplectic patients were subjected into this study and randomly divided into "JIN San Zhen" group (n=30) and control group (n=31). Blood lipid peroxidase (LPO), superoxide dismutase (SOD), glutathione peroxidase(GSH Px) and nitric oxide (NO) contents before and after acupuncture treatment were determined with radioimmunoassay. In both groups, acupuncture was given once daily, six times a week, with 4 weeks being a therapeutic course and with the interval between two weeks being a week, 3 courses all together. In "JIN San Zhen" group, acupoints of "JIN San Zhen" were used predominately, while in control group, scalp point Motor Sensory Area (MS 8) was used as the main point. Results: Self comparison showed that after 3 courses of treatment, in both groups, LPO and NO levels decreased significantly (P<0.05-0.01), SOD and GST Px values increased considerably (P<0.05-0.01). Comparison between two groups indicated that the effects of "JIN San Zhen" group are significantly superior to those of control group in raising blood SOD and GST Px levels (P<0.05-0.01) and in lowering blood NO content (P<0.01). Analysis on the correlation between the restoration of neural function and the changes of LPO, SOD and GST Px levels suggested that the effect of acupuncture in improving neural function may be related to changes of the aforementioned indexes. Conclusion: Acupuncture therapy can significantly lower blood LPO and NO levels and evidently raise blood SOD and GST Px levels in stroke patients.展开更多
文摘The oxygen evolution reaction(OER)serves as a fundamental half–reaction in the electrolysis of water for hydrogen production,which is restricted by the sluggish OER reaction kinetics and unable to be practically applied.The traditional lattice oxygen oxidation mechanism(LOM)offers an advantageous route by circumventing the formation of M-OOH^(*)in the adsorption evolution mechanism(AEM),thus enhancing the reaction kinetics of the OER but resulting in possible structural destabilization due to the decreased M–O bond order.Fortunately,the asymmetry of tetrahedral and octahedral sites in transition metal spinel oxides permits the existence of non-bonding oxygen,which could be activated by rational band structure design for direct O-O coupling,where the M–O bond maintains its initial bond order.Here,non-bonding oxygen was introduced into NiFe_(2)O_(4)via annealing in an oxygen-deficient atmosphere.Then,in-situ grown sulfate species on octahedral nickel sites significantly improved the reactivity of the non-bonding oxygen electrons,thereby facilitating the transformation of the redox center from metal to oxygen.LOM based on non-bonding oxygen(LOMNB)was successfully activated within NiFe_(2)O_(4),exhibiting a low overpotential of 206 mV to achieve a current density of 10 mA cm^(-2)and excellent durability of stable operation for over 150 h.Additionally,catalysts featuring varying band structures were synthesized for comparative analysis,and it was found that the reversible redox processes of non-bonding oxygen and the accumulation of non-bonding oxygen species containing 2p holes are critical prerequisites for triggering and sustaining the LOMNB pathway in transition metal spinel oxides.These findings may provide valuable insights for the future development of spinel-oxide-based LOM catalysts.
基金the support from the National Key R&D Program of China(2020YFA0710000)the National Natural Science Foundation of China(Nos.22008170,22278307,22222808,21978200)+1 种基金the Haihe Laboratory of Sustainable Chemical Transformationsthe Tianjin Research Innovation Project for Postgraduate Students(2022B KYZ035)。
文摘Water electrolysis,a process for producing green hydrogen from renewable energy,plays a crucial role in the transition toward a sustainable energy landscape and the realization of the hydrogen economy.Oxygen evolution reaction(OER)is a critical step in water electrolysis and is often limited by its slow kinetics.Two main mechanisms,namely the adsorbate evolution mechanism(AEM)and lattice oxygen oxidation mechanism(LOM),are commonly considered in the context of OER.However,designing efficient catalysts based on either the AEM or the LOM remains a topic of debate,and there is no consensus on whether activity and stability are directly related to a certain mechanism.Considering the above,we discuss the characteristics,advantages,and disadvantages of AEM and LOM.Additionally,we provide insights on leveraging the LOM to develop highly active and stable OER catalysts in future.For instance,it is essential to accurately differentiate between reversible and irreversible lattice oxygen redox reactions to elucidate the LOM.Furthermore,we discuss strategies for effectively activating lattice oxygen to achieve controllable steady-state exchange between lattice oxygen and an electrolyte(OH^(-)or H_(2)O).Additionally,we discuss the use of in situ characterization techniques and theoretical calculations as promising avenues for further elucidating the LOM.
基金The work is supported by The Department of Education of Heilongjiang Province.
文摘Selective oxidation of propane by lattice oxygen of vanadium-phosphorus oxide(VPO) catalysts was investigated with a pulse reactor in which the oxidation of propane and there-oxidation of catalyst were implemented alternately in the presence of water vapor. The principalproducts are acrylic acid (AA), acetic acid (HAc), and carbon oxides. In addition, small amounts ofC_1 and C_2 hydrocarbons were also found, molar ratio of AA to HAc is 1.4-2.2. The active oxygenspecies are those adsorbed on catalyst surface firmly and/or bound to catalyst lattice, i.e. latticeoxygen; the selective oxidation of propane on VPO catalysts can be carried out in a circulatingfluidized bed (CFB) riser reactor. For propane oxidation over VPO catalysts, the effects of reactiontemperature in a pulse reactor were found almost the same as in a steady-state flow reactor. Thatis, as the reaction temperature increases, propane conversion and the amount of C_1+C_2 hydrocarbonsin the product increase steadily, while selectivity to acrylic acid and to acetic acid increaseprior to 350℃ then begin to drop at temperatures higher than 350℃, and yields of acrylic acid andof acetic acid attained maximum at about 400℃. The maximum yields of acrylic acid and of aceticacid for a single-pass are 7.50% and 4.59% respectively, with 38.2% propane conversion. When theamount of propane pulsed decreases or the amount of catalyst loaded increases, the conversionincreases but the selectivity decreases. Increasing the flow rate of carrier gases causes theconversion pass through a minimum but selectivity and yields pass through a maximum. In a fixed bedreactor, it is hard to obtain high selectivity at a high reaction conversion due to the furtherdegradation of acrylic acid and acetic acid even though propane was oxidized by the lattice oxygen.The catalytic performance can be improved in the presence of excess propane. Propylene can beoxidized by lattice oxygen of VPO catalyst at 250℃, nevertheless, selectivity to AA and to HAc areeven lower, much more acetic acid was produced (molar ratio of AA to HAc is 0.19:1-0.83:1) thoughthe oxidation products are the same as from propane.
基金supported by the Science and Technology Research Program of Chongqing Municipal Education Commission(KJQN202200550)the Natural Science Foundation Joint Fund for Innovation and Development of Chongqing Municipal Education Commission(CSTB2022NSCQ-LZX0077)+4 种基金the National Natural Science Foundation of China(No.52100065)the Science and Technology Research Program of Natural Science Foundation of Chongqing(cstc2021ycjh-bgzxm0037)the Science and Technology Research Program of Chongqing Municipal Education Commission(KJZD-M202200503)the Chongqing Innovation Research Group Project(No.CXQT21015)the Doctor Start/Talent Introduction Program of Chongqing Normal University(No.02060404/2020009000321)。
文摘Transition metal chalcogenides(TMCs)are recognized as pre-catalysts,and their(oxy)hydroxides derived from electrochemical reconstruction are the active species in the water oxidation.However,understanding the role of the residual chalcogen in the reconstructed layer is lacking in detail,and the corresponding catalytic mechanism remains controversial.Here,taking Cu_(1-x)Co_(x)S as a platform,we explore the regulating effect and existence form of the residual S doped into the reconstructive layer for oxygen evolution reaction(OER),where a dual-path OER mechanism is proposed.First-principles calculations and operando~(18)O isotopic labeling experiments jointly reveal that the residual S in the reconstructive layer of Cu_(1-x)Co_(x)S can wisely balance the adsorbate evolution mechanism(AEM)and lattice oxygen oxidation mechanism(LOM)by activating lattice oxygen and optimizing the adsorption/desorption behaviors at metal active sites,rather than change the reaction mechanism from AEM to LOM.Following such a dual-path OER mechanism,Cu_(0.4)Co_(0.6)S-derived Cu_(0.4)Co_(0.6)OSH not only overcomes the restriction of linear scaling relationship in AEM,but also avoids the structural collapse caused by lattice oxygen migration in LOM,so as to greatly reduce the OER potential and improved stability.
基金financial support by the Program for the Outstanding Innovative Teams of Higher Learning Institutions of Shanxi(OIT)Shanxi Province Hundred Talent Project
文摘In recent decade, Au nanoclusters of atomic precision （AunLm, where L= organic ligand： thiolate andphosphine） have been shown as a new promising nanogold catalyst. The well-defined AunLm catalystspossess unique electronic properties and frameworks, providing an excellent opportunity to correlate theintrinsic catalytic behavior with the cluster＇s framework as well as to study the catalytic mechanismsover gold nanoclusters. In this review, we only demonstrate the important roles of the gold nanoclustersin the oxygen activation （e.g., 302 to 102） and their selective oxidations in the presence of oxygen （e.g., COto C02, sulfides to sulfoxides, alcohol to aldehyde, styrene to styrene epoxide, amines to imines, andglucose to gluconic acid）. The size-specificity （Au25 （1.3 nm）, Au38 （].5 nm）, Au144 （1.9 nm）, etc.）, ligandengineering （e.g., aromatic vs aliphatic）, and doping effects （e.g., copper, silver, palladium, and platinum）are discussed in details. Finally, the proposed reactions＇ mechanism and the relationships of clusters＇structure and activity at the atomic level also are presented.
基金Project supported by the National key research and development program(2016YFC0204901)the National Natural Science Foundation of China(21576207)+1 种基金the Introduction Of Talent and Technology Cooperation Plan Of Tianjin(14RCGFGX00849)GM Global Research&Development(GAC 1539)
文摘This study was focused on the influence of active oxygen on the performance of Pt/CeO2 catalysts for CO oxidation. A series of CeO2 supports with different contents of active oxygen were obtained by adding surfactant at different synthesis steps. 0.25 wt% Pt was loaded on these CeO2 supports by incipientwetness impregnation methods. The catalysts were characterized by N2 adsorption, X-ray diffraction（XRD）, high-resolution transmission electron microscopy（HRTEM）, H2 temperature-programmed reduction（H2-TPR）, dynamic oxygen storage capacity（DOSC） and in-situ DRIFTS technologies. For S-f supports, the surfactant was added into the solution before spray-drying in the synthesis process, which facilitates more active oxygen formation on the surface of CeO2. After loading Pt, the more active oxygen on CeO2 contributes to dispersing Pt species and enhancing the CO oxidation activity. As for the aged samples,Pt-R-h shows the highest activity above 190 ℃ because of the presence of more partly oxidized Pt^（δ＋） species. Thus the activity is also influenced by the states of Pt and the Pt^（δ＋） species may contribute to the high activity at elevated temperature.
文摘Kinetics of oxygen adsorption on single crystal Mn<sub>5</sub>Si<sub>3</sub> （111） surface and initial surface oxidation were investigated. Oxygen chemisorbs dissociatively at room temperature on Mn and Si atoms. A fast oxidation of Si atoms occurs followed by oxidation of Mn atoms at RT. The MnO<sub>2</sub> was reduced by Si atoms and the SiO was oxidized further to SiO<sub>2</sub> during the sample heating.
基金financially supported by the National Natural Science Foundation of China(No.51274154)The Major Projects of Technology Innovation of Hubei Province,China(No.2017AAA116)the Special Fund of Wuhan University of Science and Technology for Master Student’s Short-Term Studying Abroad
文摘The oxidizing behavior of Si-containing steel was investigated in an O2 and N2 binary-component gas with oxygen contents ranging between 0.5 vol% and 4.0 vol% under anisothermal-oxidation conditions. A simultaneous thermal analyzer was employed to simulate the heating process of Si-containing steel in industrial reheating furnaces. The oxidation gas mixtures were introduced from the commencement of heating. The results show that the oxidizing rate remains constant in the isothermal holding process at high temperatures; therefore, the mass change versus time presents a linear law. A linear relation also exists between the oxidizing rate and the oxygen content. Using the linear regression equation, the oxidation rate at different oxygen contents can be predicted. In addition, the relationship between the total mass gain and the oxygen content is linear; thus, the total mass gain at oxygen contents between 0.5 vol%–4.0 vol% can be determined. These results enrich the theoretical studies of the oxidation process in Si-containing steels.
基金supported by the National Basic Research Program of China(2011CB933700)the National Natural Science Foundation of China(21271165)~~
文摘With the objectives of enhancing the stability,optical properties and visible-light photocatalytic activity of photocatalysts,we modified oxygen vacancy-rich zinc oxide（Vo-ZnO） with graphitic carbon nitride（g-C3N4）. The resulting g-C3N4/Vo-ZnO hybrid photocatalysts showed higher visible-light photocatalytic activity than pure Vo-ZnO and g-C3N4. The hybrid photocatalyst with a g-C3N4 content of 1 wt% exhibited the highest photocatalytic degradation activity under visible-light irradiation（λ≥ 400 nm）. In addition,the g-C3N4/Vo-ZnO photocatalyst was not deactivated after five cycles of methyl orange degradation,indicating that it is stable under light irradiation. Finally,a Z-scheme mechanism for the enhanced photocatalytic activity and stability of the g-C3N4/Vo-ZnO hybrid photocatalyst was proposed. The fast charge separation and transport within the g-C3N4/Vo-ZnO hybrid photocatalyst were attributed as the origins of its enhanced photocatalytic performance.
基金support from the U.S.Department of the Army and U.S.Army Future Commandsupport from the U.S.Army Research Laboratory Senior Research Fellowship Program。
文摘The oxygen evolution reaction(OER)is the essential module in energy conversion and storage devices such as electrolyzer,rechargeable metal–air batteries and regenerative fuel cells.The adsorption energy scaling relations between the reaction intermediates,however,impose a large intrinsic overpotential and sluggish reaction kinetics on OER catalysts.Developing advanced electrocatalysts with high activity and stability based on non-noble metal materials is still a grand challenge.Central to the rational design of novel and high-efficiency catalysts is the development and understanding of quantitative structure–activity relationships,which correlate the catalytic activities with structural and electronic descriptors.This paper comprehensively reviews the benchmark descriptors for OER electrolysis,aiming to give an in-depth understanding on the origins of the electrocatalytic activity of the OER and further contribute to building the theory of electrocatalysis.Meanwhile,the cutting-edge research frontiers for proposing new OER paradigms and crucial strategies to circumvent the scaling relationship are also summarized.Challenges,opportunities and perspectives are discussed,intending to shed some light on the rational design concepts and advance the development of more efficient catalysts for enhancing OER performance.
基金supported by the National Natural Science Foundation of China(Nos.52177220,52231008)Key Research and Development Program of Hainan Province(ZDYF2022GXJS006)。
文摘The lattice oxygen oxidation mechanism(LOM)provides an efficient pathway for accelerating the oxygen evolution reaction(OER)in certain electrocatalysts by activating and involving lattice oxygen in the catalytic OER process.We investigated the potential of disordered rocksalts as catalysts for accelerating the OER through the LOM process,leveraging their unique metastable Li-O-Li bond states.Theoretical calculations were employed to predict the catalytic pathways and activities of disordered rocksalts(DRX),such as Li_(1.2)Co_(0.4)Ti_(0.5)O_(2)(LCTO).The results revealed that benefiting from the unhybridized Li-O electronic orbitals and the resulting metastable states of Li-O-Li bonds in DRX,LCTO exhibited a typical LOM pathway,and the lattice oxygen was easily activated and participated in the OER.The experimental results showed that LCTO exhibited a remarkable pH-dependent OER activity through the LOM pathway,with an overpotential of 241 mV at a current density of 10 mA/cm^(2),and excellent long-term stability.This work provides a novel chemical space for designing highly active and stable OER electrocatalysts by leveraging the LOM reaction pathway.
基金supported financially by the National Natural Science Foundation of China (91545103,21103048)
文摘Selective oxidation of saturated hydrocarbons with molecular oxygen has been of great interest in catalysis, and the development of highly efficient catalysts for this process is a crucial challenge. A new kind of heterogeneous catalyst, cobalt-doped carbon nitride polymer(g-C_3N_4),was harnessed for the selective oxidation of cyclohexane. X-ray diffraction, Fourier transform infrared spectra and high resolution transmission electron microscope revealed that Co species were highly dispersed in g-C_3N_4 matrix and the characteristic structure of polymeric g-C_3N_4 can be retained after Co-doping, although Co-doping caused the incomplete polymerization to some extent. Ultraviolet-visible, Raman and X-ray photoelectron spectroscopy further proved the successful Co doping in g-C_3N_4 matrix as the form of Co(Ⅱ)-N bonds. For the selective oxidation of cyclohexane, Co-doping can markedly promote the catalytic performance of g-C_3N_4 catalyst due to the synergistic effect of Co species and gC_3N_4 hybrid. Furthermore, the content of Co largely affected the activity of Co-doped g-C_3N_4 catalysts, among which the catalyst with 9.0 wt%Co content exhibited the highest yield(9.0%) of cyclohexanone and cyclohexanol, as well as a high stability. Meanwhile, the reaction mechanism over Co-doped g-C_3N_4 catalysts was elaborated.
基金supported by the Department of Science and Technology,New Delhi,under SERB Scheme(SB/S1/PC-106/2012)
文摘In this work, the influence of trivalent rare-earth dopants（Sm and La） on the structure-activity properties of CeO2 was thoroughly studied for diesel soot oxidation. For this, an optimized 40% of Sm and La was incorporated into the CeO2 using a facile coprecipitation method from ultra-high dilute aqueous solutions. A systematic physicochemical characterization was carried out using X-ray diffraction（XRD）, transmission electron microscopy（TEM）, Brumauer-Emmett-teller method（BET） surface area, X-ray photoelectron spectroscopy（XPS）, Raman, and H2-temperature programmed reduction（TPR） techniques. The soot oxidation efficiency of the catalysts was investigated using a thermogravimetric method. The XRD results suggested the formation of nanocrystalline single phase CeO2-Sm2O3 and CeO2-La2O3 solid solutions. The Sm- and La-doped CeO2 materials exhibited smaller crystallite size and higher BET surface area compared with the pure CeO2. Owing to the difference in the oxidation states of the dopants（Sm3＋ and La3＋） and the Ce4＋, a number of oxygen vacancies were generated in CeO2-Sm2O3 and CeO2-La2O3 samples. The H2-TPR studies evidenced the improved reducible nature of the CeO2-Sm2O3 and CeO2-La2O3 samples compared with the CeO2. It was found that the addition of Sm and La to the CeO2 outstandingly enhanced its catalytic efficiency for the oxidation of diesel soot. The observed 50% soot conversion temperatures for the CeO2-Sm2O3, CeO2-La2O3 and CeO2 were ~790, 843 and 864 K（loose contact）, respectively, and similar activity order was also found under the tight contact condition. The high soot oxidation efficacy of the CeO2-Sm2O3 sample was attributed to numerous catalytically favourable properties, like smaller crystallite size, larger surface area, abundant oxygen vacancies, and superior reducible nature.
基金supported by the Special Research Foundation of Doctoral Course in Colleges and Universities of China in 2013,No.20133420110009
文摘Postoperative cognitive dysfunction is a crucial public health issue that has been increasingly studied in efforts to reduce symptoms or prevent its occurrence. However, effective advances remain lacking. Hyperbaric oxygen preconditioning has proved to protect vital organs, such as the heart, liver, and brain. Recently, it has been introduced and widely studied in the prevention of postoperative cognitive dysfunction, with promising results. However, the neuroprotective mechanisms underlying this phenomenon remain controversial. This review summarizes and highlights the definition and application of hyperbaric oxygen preconditioning, the perniciousness and pathogenetic mechanism underlying postoperative cognitive dysfunction, and the effects that hyperbaric oxygen preconditioning has on postoperative cognitive dysfunction. Finally, we conclude that hyperbaric oxygen preconditioning is an effective and feasible method to prevent, alleviate, and improve postoperative cognitive dysfunction, and that its mechanism of action is very complex, involving the stimulation of endogenous antioxidant and anti-inflammation defense systems.
基金financially supported by the National Natural Science Foundation of China (Nos. 21376224, 21206147)
文摘An efficient and convenient tert-butyl nitrite-catalyzed selective aerobic oxidation of thiols has been developed. Under the optimal reaction conditions, a number of thiol derivatives including aromatic thiols, heteroaromatic thiols and aliphatic thiols can be converted into their corresponding disulfides in good to excellent yields.
基金supported by the National 973 Program of China (2012CB416804 and 2014CB440906)CAS/SAFEA International Partnership Program for Creative Research Teams (KZZD-EW-TZ-20)National Natural Sciences Foundations of China (41473051) to Tao yan
文摘Economic concentrations of Fe–Ti oxides occurring as massive layers in the middle and upper parts of the Hongge intrusion are different from other layered intrusions(Panzhihua and Baima) in the Emeishan large igneous province, SW China. This paper reports on the new mineral compositions of magnetite and ilmenite for selected cumulate rocks and clinopyroxene and plagioclase for basalts. We use these data to estimate the oxidation state of parental magmas and during ore formation to constrain the factors leading to the abundant accumulation of Fe–Ti oxides involved with the Hongge layered intrusion. The results show that the oxygen fugacities of parental magma are in the range of FMQ-1.56 to FMQ+0.14, and the oxygen fugacities during the ore formation of the Fe–Ti oxides located in the lower olivine clinopyroxenite zone(LOZ) and the middle clinopyroxenite zone(MCZ) of the Hongge intrusion are in the range of FMQ-1.29 to FMQ-0.2 and FMQ-0.49 to FMQ+0.82, respectively.The MELTS model demonstrates that, as the oxygen fugacity increases from the FMQ-1 to FMQ+1, the proportion of crystallization magnetite increases from 11 % to 16 % and the crystallization temperature of the Fe–Ti oxides advances from 1134 to 1164 °C. The moderate oxygen fugacities for the Hongge MCZ indicate that the oxygen fugacity was not the only factor affecting the crystallization of Fe–Ti oxides. We speculated that theinitial anhydrous magma that arrived at the Hongge shallow magma chamber became hydrous by attracting the H_2O of the strata. In combination with increasing oxygen fugacities from the LOZ(FMQ-1.29 to FMQ-0.2) to the MCZ(FMQ-0.49 to FMQ+0.82), these two factors probably account for the large-scale Fe–Ti oxide ore layers in the MCZ of the Hongge intrusion.
基金Project supported by the Introduction of Talent and Technology Cooperation Plan of Tianjin
文摘Pd@Zr/Ce O2 core-shell catalyst prepared by hydrothermal method was applied in CO oxidation reaction, exhibiting high CO oxidation activity at low temperature.XRD（X-ray diffraction） analysis demonstrated that the remarkable enhancement of catalytic performance was found to depend on the presence of more oxygen vacancies in the core-shell structure, which contributed higher content of and ready release of active oxygen species at low temperature, confirmed by H2-TPR（temperature programed reduction） results.Interestingly, introducing a small amount of zirconium（0.5 wt.%） exhibited a significant improvement of catalytic activity because the introduction of Zr further improved the amount of crystal defects and promoted the migration of oxygen species.
基金supported by the National Natural Science Foundation of China (21107124, 21337003)the Youth Innovation Promotion Association (2011037)Science Promotion Program of Research Center for Eco-Environmental Sciences, Chinese Academic Sciences (No. 121311RCEES-QN-20130046F)
文摘We describe here a one-step method for the synthesis of Au/TiO2 nanosphere materials,which were formed by layered deposition of multiple anatase TiO2 nanosheets.The Au nanoparticles were stabilized by structural defects in each TiO2 nanosheet,including crystal steps and edges,thereby fixing the Au-TiO2 perimeter interface.Reactant transfer occurred along the gaps between these TiO2 nanosheet layers and in contact with catalytically active sites at the Au-TiO2 interface.The doped Au induced the formation of oxygen vacancies in the Au-TiO2 interface.Such vacancies are essential for generating active oxygen species（-＊O^-） on the TiO2 surface and Ti^3＋ ions in bulk TiO2.These ions can then form Ti^3＋-O^--Ti^4＋species,which are known to enhance the catalytic activity of formaldehyde（HCHO） oxidation.These studies on structural and oxygen vacancy defects in Au/TiO2 samples provide a theoretical foundation for the catalytic mechanism of HCHO oxidation on oxide-supported Au materials.
基金financially supported by the National Natural Science Foundation of China(Nos.21307142 and 21403261)Ningbo Science and Technology Bureau(No.2014D10004)
文摘The functionalization of multi-walled carbon nanotubes （MWCNTs） by ozone treatment has been sys- tematically investigated by using Raman spectroscopy, transmission electron microscopy （TEM）, Fourier transform inhared spectroscopy （FTIR）, X-ray photoelectron spectroscopy （XPS）, organic elemental anal- ysis （OEA） and Boehm titration. The results showed that the functionalization process occurred at defective sites （opened mouths, tube caps, debris, etc.） before opening caps and truncating walls, and finally the graphitic structure was deteriorated. The surface oxygen content first increased with the treatment time but kept at around 8.0 wt% after 5 h. The analysis of the distribution of oxygen-containing groups re- vealed that phenolic hydroxyl was gradually converted to carboxyl and lactone, The carboxyl was found to play a pivotal role to reduce the over-potentials when we used the functionalized MWCNTs as the cat- alyst for oxygen reduction reaction （ORR）.
文摘Objective: To observe the effect of acupuncture on blood oxygen free radical (OFR) and nitric oxide (NO) levels in the treatment of apoplectic sequelae. Methods: A total of 61 cases of apoplectic patients were subjected into this study and randomly divided into "JIN San Zhen" group (n=30) and control group (n=31). Blood lipid peroxidase (LPO), superoxide dismutase (SOD), glutathione peroxidase(GSH Px) and nitric oxide (NO) contents before and after acupuncture treatment were determined with radioimmunoassay. In both groups, acupuncture was given once daily, six times a week, with 4 weeks being a therapeutic course and with the interval between two weeks being a week, 3 courses all together. In "JIN San Zhen" group, acupoints of "JIN San Zhen" were used predominately, while in control group, scalp point Motor Sensory Area (MS 8) was used as the main point. Results: Self comparison showed that after 3 courses of treatment, in both groups, LPO and NO levels decreased significantly (P<0.05-0.01), SOD and GST Px values increased considerably (P<0.05-0.01). Comparison between two groups indicated that the effects of "JIN San Zhen" group are significantly superior to those of control group in raising blood SOD and GST Px levels (P<0.05-0.01) and in lowering blood NO content (P<0.01). Analysis on the correlation between the restoration of neural function and the changes of LPO, SOD and GST Px levels suggested that the effect of acupuncture in improving neural function may be related to changes of the aforementioned indexes. Conclusion: Acupuncture therapy can significantly lower blood LPO and NO levels and evidently raise blood SOD and GST Px levels in stroke patients.
