Regulation with nitrogen and oxygen co-doping on growth and properties of boron doped diamond films is studied by using laughing gas as dopant. As the concentration of laughing gas(N2O/C) increases from 0 to 10%, the ...Regulation with nitrogen and oxygen co-doping on growth and properties of boron doped diamond films is studied by using laughing gas as dopant. As the concentration of laughing gas(N2O/C) increases from 0 to 10%, the growth rate of diamond film decreases gradually, and the nitrogen-vacancy(NV) center luminescence intensity increases first and then weakens. The results show that oxygen in laughing gas has a strong inhibitory effect on formation of NV centers, and the inhibitory effect would be stronger as the concentration of laughing gas increases. As a result, the film growth rate and nitrogen-related compensation donor decrease, beneficial to increase the acceptor concentration(~3.2×10^(19)cm^(-3)) in the film. Moreover, it is found that the optimal regulation with the quality and electrical properties of boron doped diamond films could be realized by adding appropriate laughing gas, especially the hole mobility(~700cm^(2)/V·s), which is beneficial to the realization of high-quality boron doped diamond films and high-level optoelectronic device applications in the future.展开更多
Radiation induced reactive oxygen/nitrogen species (ROS/RNS) are reported to cause lung injuries such as pneumonitis and fibrosis which may be fatal at times. Current study is designed to analyse the radioprotective e...Radiation induced reactive oxygen/nitrogen species (ROS/RNS) are reported to cause lung injuries such as pneumonitis and fibrosis which may be fatal at times. Current study is designed to analyse the radioprotective efficacy of P. hexandrum active principles (G-002M) on lungs of mice exposed to high dose of gamma irradiation (7 Gy). Cellular profiles and inflammatory cell infiltrates of irradiated bronchoalveolar lavage fluid (BALF) have shown correlations with lung pathology. Cell counts were determined in BALF of control, 7 Gy radiation exposed and radiation with G-002M pretreated mice. ROS/Nitric Oxide (NO) production was measured by 2,7?dichlorodihydrofluorescein diacetate (DCF-DA) and diaminofluorescein diacetate (DAF-2DA) through microscopy and flow cytometry respectively. Immunostaining of inducible nitric oxide synthase (iNOS) in BALF cells and lung sections was also observed microscopically. iNOS ex- pression was observed in lungs by western blotting. BALF was also processed to estimate total protein, LDH, and phospholipids content. Catalase, reduced Glutathione (GSH), Glutathione reductase (GR) and lipid peroxidation were estimated in lung tissues. Pre-administration of G-002M significantly decreased radiation mediated neutrophils count in BALF of irradiated mice. ROS generation, iNOS expression, total protein, LDH and phospholipids were found less affected in G-002M pretreated group in comparison to radiation alone group. Radiation exposure to mice was found apparently leading to parenchymal fibrosis, an architectural distortion of the lung tissue with edema, infiltration of inflammatory blood cells with increased immunolabeling of iNOS. G-002M pretreatment significantly countered radiation mediated increased lipid peroxidation and decreased GR, catalase and GSH in mice. Current study demonstrates possible role of P. hexandrum (G-002M) in minimizing lung damage induced by radiation mediated ROS/RNS generation.展开更多
Rational design and construction of oxygen reduction reaction(ORR)electrocatalysts with high activity,good stability,and low price are essential for the practical applications of renewable energy conversion devices,su...Rational design and construction of oxygen reduction reaction(ORR)electrocatalysts with high activity,good stability,and low price are essential for the practical applications of renewable energy conversion devices,such as metal-air batteries.Electronic modification through constructing metal/semiconductor Schottky heterointerface represents a powerful strategy to enhance the electrochemical performance.Herein,we demonstrate a concept of Schottky electrocatalyst composed of uniform Co nanoparticles in situ anchored on the carbon nanotubes aligned on the carbon nanosheets(denoted as Co@N-CNTs/NSs hereafter)toward ORR.Both experimental findings and theoretical simulation testify that the rectifying contact could impel the voluntary electron flow from Co to N-CNTs/NSs and create an internal electric field,thereby boosting the electron transfer rate and improving the intrinsic activity.As a consequence,the Co@N-CNTs/NSs deliver outstanding ORR activity,impressive long-term durability,excellent methanol tolerance,and good performance as the air-cathode in the Zn-air batteries.The design concept of Schottky contact may provide the innovational inspirations for the synthesis of advanced catalysts in sustainable energy conversion fields.展开更多
Eutrophication caused by inputs of excess nitrogen(N) has become a serious environmental problem in Hangzhou Bay(China),but the sources of this nitrogen are not well understood.In this study,the August 2019 distributi...Eutrophication caused by inputs of excess nitrogen(N) has become a serious environmental problem in Hangzhou Bay(China),but the sources of this nitrogen are not well understood.In this study,the August 2019 distributions of salinity,nutrients [nitrate(NO_(3)^(-)),nitrite,ammonium,and phosphate],and the stable isotopic composition of NO_(3)^(-)(δ^(15)N and δ^(18)O) were used to investigate sources of dissolved inorganic nitrogen(DIN) to Hangzhou B ay.Spatial distributions of nitrate,salinity,and nitrate δ^(18)O indicate that the Qiantang River,the Changjiang River,and nearshore coastal waters may all contribute nitrate to the bay.Based on the isotopic compositions of nitrate in these potential source waters and conservative mixing of nitrate in our study area,we suggest that the NO_(3)^(- )in Hangzhou B ay was likely derived mainly from soils,synthetic N fertilizer,and manure and sewage.End-member modeling indicates that in the upper half of the bay,the Qiantang River was a very important DIN source,possibly contributing more than 50% of DIN in the bay head area.In the lower half of the bay,DIN was sourced mainly from strongly intruding coastal water.DIN coming directly from the Changjiang River made a relatively small contribution to Hangzhou Bay DIN in August 2019.展开更多
Transition metal-nitrogen-carbon(M-N-C)as a promising substitute for the conventional noble metalbased catalyst still suffers from low activity and durability for oxygen reduction reaction(ORR)in proton exchange membr...Transition metal-nitrogen-carbon(M-N-C)as a promising substitute for the conventional noble metalbased catalyst still suffers from low activity and durability for oxygen reduction reaction(ORR)in proton exchange membrane fuel cells(PEMFCs).To tackle the issue,herein,a new type of sulfur-doped ironnitrogen-hard carbon(S-Fe-N-HC)nanosheets with high activity and durability in acid media were developed by using a newly synthesized precursor of amide-based polymer with Fe ions based on copolymerizing two monomers of 2,5-thiophene dicarboxylic acid(TDA)as S source and 1,8-diaminonaphthalene(DAN)as N source via an amination reaction.The as-synthesized S-Fe-N-HC features highly dispersed atomic Fe Nxmoieties embedded into rich thiophene-S doped hard carbon nanosheets filled with highly twisted graphite-like microcrystals,which is distinguished from the majority of M-N-C with soft or graphitic carbon structures.These unique characteristics endow S-Fe-N-HC with high ORR activity and outstanding durability in 0.5 M H_(2)SO_(4).Its initial half-wave potential is 0.80 V and the corresponding loss is only 21 m V after 30,000 cycles.Meanwhile,its practical PEMFC performance is a maximum power output of 628.0 mW cm^(-2)and a slight power density loss is 83.0 m W cm^(-2)after 200-cycle practical operation.Additionally,theoretical calculation shows that the activity of Fe Nxmoieties on ORR can be further enhanced by sulfur doping at meta-site near FeN_(4)C.These results evidently demonstrate that the dual effect of hard carbon substrate and S doping derived from the precursor platform of amid-polymers can effectively enhance the activity and durability of Fe-N-C catalysts,providing a new guidance for developing advanced M-N-C catalysts for ORR.展开更多
The interaction between metal and support is critical in oxygen catalysis as it governs the charge transfer between these two entities,influences the electronic structures of the supported metal,affects the adsorption...The interaction between metal and support is critical in oxygen catalysis as it governs the charge transfer between these two entities,influences the electronic structures of the supported metal,affects the adsorption energies of reaction intermediates,and ultimately impacts the catalytic performance.In this study,we discovered a unique charge transfer reversal phenomenon in a metal/carbon nanohybrid system.Specifically,electrons were transferred from the metal-based species to N-doped carbon,while the carbon support reciprocally donated electrons to the metal domain upon the introduction of nickel.This led to the exceptional electrocatalytic performances of the resulting Ni-Fe/Mo_(2)C@nitrogen-doped carbon catalyst,with a half-wave potential of 0.91 V towards oxygen reduction reaction(ORR)and a low overpotential of 290 m V at 10 mA cm^(-2)towards oxygen evolution reaction(OER)under alkaline conditions.Additionally,the Fe-Ni/Mo_(2)C@carbon heterojunction catalyst demonstrated high specific capacity(794 mA h g_(Zn)~(-1))and excellent cycling stability(200 h)in a Zn-air battery.Theoretical calculations revealed that Mo_(2)C effectively inhibited charge transfer from Fe to the support,while secondary doping of Ni induced a charge transfer reversal,resulting in electron accumulation in the Fe-Ni alloy region.This local electronic structure modulation significantly reduced energy barriers in the oxygen catalysis process,enhancing the catalytic efficiency of both ORR and OER.Consequently,our findings underscore the potential of manipulating charge transfer reversal between the metal and support as a promising strategy for developing highly-active and durable bi-functional oxygen electrodes.展开更多
Controlling the local electronic structure of active ingredients to improve the adsorption desorption characteristics of oxygen-containing intermediates over the electrochemical liquid-solid interfaces is a critical c...Controlling the local electronic structure of active ingredients to improve the adsorption desorption characteristics of oxygen-containing intermediates over the electrochemical liquid-solid interfaces is a critical challenge in the field of oxygen reduction reaction(ORR)catalysis.Here,we offer a simple approach for modulating the electronic states of metal nanocrystals by bimetal co-doping into carbon-nitrogen substrate,allowing us to modulate the electronic structure of catalytic active centers.To test our strategy,we designed a typical bimetallic nanoparticle catalyst(Fe-Co NP/NC)to flexibly alter the reaction kinetics of ORR.Our results from synchrotron Xray absorption spectroscopy and X-ray photoelectron spectroscopy showed that the co-doping of iron and cobalt could optimize the intrinsic charge distribution of Fe-Co NP/NC catalyst,promoting the oxygen reduction kinetics and ultimately achieving remarkable ORR activity.Consequently,the carefully designed Fe-Co NP/NC exhibits an ultra-high kinetic current density at the operating voltage(71.94 mA/cm^(2)at 0.80 V),and the half-wave potential achieves 0.915 V,which is obviously better than that of the corresponding controls including Fe NP/NC,Co NP/NC.Our findings provide a unique perspective for optimizing the electronic structure of active centers to achieve higher ORR catalytic activity and faster kinetics.展开更多
Metal-free carbon-based materials offer a promising alternative to Pt-based catalysts for the oxygen reduction reaction (ORR).However,challenges persist due to its sluggish kinetics and poor acid ORR performance.Here,...Metal-free carbon-based materials offer a promising alternative to Pt-based catalysts for the oxygen reduction reaction (ORR).However,challenges persist due to its sluggish kinetics and poor acid ORR performance.Here,we introduce a novel nitrogen-doped porous carbon with rich defects sites (such as pentagons,edge and vacancy defects)(PV/HPC) via a simple etching strategy.The PV/HPC demonstrates long-term stability and exceptional catalytic activity with half-wave potential of 0.9 V and average electron transfer number of 3.98 in alkaline solution while 0.78 V and 3.78 in acidic solution,indicating its efficiency and robustness as an ORR catalyst.Additionally,it achieves a higher kinetic current density of 91.9 m A cm^(-2)at 0.8 V,which is 1.75 times that of Pt/C (52.5 mA cm^(-2)).Furthemore,it enables Al-air battery to attain a maximum power density of 487 mW cm^(-2),compared to 477 mW cm^(-2) for the Pt/C catalyst.Density functional theory (DFT) calculations elucidate that the introduction of multifunctional defects in nitrogen-doped porous carbon collectively reduces the reaction energy barrier of the departure of OH*and boosts the oxygen reduction reaction kinetics.This work presents a simple method to design durable and effective carbon-based ORR catalysts.展开更多
Catalyst–support interaction plays a crucial role in improving the catalytic activity of oxygen evolution reaction(OER).Here we modulate the catalyst–support interaction in polyaniline-supported Ni_(3)Fe oxide(Ni_(3...Catalyst–support interaction plays a crucial role in improving the catalytic activity of oxygen evolution reaction(OER).Here we modulate the catalyst–support interaction in polyaniline-supported Ni_(3)Fe oxide(Ni_(3)Fe oxide/PANI)with a robust hetero-interface,which significantly improves oxygen evolution activities with an overpotential of 270 mV at 10 mA cm^(-2)and specific activity of 2.08 mA cm_(ECSA)^(-2)at overpotential of 300 mV,3.84-fold that of Ni_(3)Fe oxide.It is revealed that the catalyst–support interaction between Ni_(3)Fe oxide and PANI support enhances the Ni–O covalency via the interfacial Ni–N bond,thus promoting the charge and mass transfer on Ni_(3)Fe oxide.Considering the excellent activity and stability,rechargeable Zn-air batteries with optimum Ni_(3)Fe oxide/PANI are assembled,delivering a low charge voltage of 1.95 V to cycle for 400 h at 10 mA cm^(-2).The regulation of the effect of catalyst–support interaction on catalytic activity provides new possibilities for the future design of highly efficient OER catalysts.展开更多
Although poly(lactic acid)(PLA)is a good environmentally-friendly bio-degradable polymer which is used to substitute traditional petrochemical-based polymer packaging films,the barrier properties of PLA films are stil...Although poly(lactic acid)(PLA)is a good environmentally-friendly bio-degradable polymer which is used to substitute traditional petrochemical-based polymer packaging films,the barrier properties of PLA films are still insufficient for high-barrier packaging applications.In this study,oxygen scavenger hydroxyl-terminated polybutadiene(HTPB)and cobalt salt catalyst were incorporated into the PLA/poly(butylene adipate-co-terephthalate)(PLA/PBAT),followed by melting extrusion and three-layer co-extrusion blown film process to prepare the composite films.The oxygen permeability coefficient of the composite film combined with 6 wt%oxygen scavenger and 0.4 wt%catalyst was decreased significantly from 377.00 cc·mil·m^(-2)·day^(-1)·0.1 MPa^(-1) to 0.98 cc·mil·m^(-2)·day^(-1)·0.1 MPa^(-1),showing a remarkable enhancement of 384.69 times compared with the PLA/PBAT composite film.Meanwhile,the degradation behavior of the composite film was also accelerated,exhibiting a mass loss of nearly 60%of the original mass after seven days of degradation in an alkaline environment,whereas PLA/PBAT composite film only showed a mass loss of 32%.This work has successfully prepared PLA/PBAT composite films with simultaneously improved oxygen barrier property and degradation behavior,which has great potential for high-demanding green chemistry packaging industries,including food,agricultural,and military packaging.展开更多
The rich resources and unique environment of the Moon make it an ideal location for human expansion and the utilization of extraterrestrial resources.Oxygen,crucial for supporting human life on the Moon,can be extract...The rich resources and unique environment of the Moon make it an ideal location for human expansion and the utilization of extraterrestrial resources.Oxygen,crucial for supporting human life on the Moon,can be extracted from lunar regolith,which is highly rich in oxygen and contains polymetallic oxides.This oxygen and metal extraction can be achieved using existing metallurgical techniques.Furthermore,the ample reserves of water ice on the Moon offer another means for oxygen production.This paper offers a detailed overview of the leading technologies for achieving oxygen production on the Moon,drawing from an analysis of lunar resources and environmental conditions.It delves into the principles,processes,advantages,and drawbacks of water-ice electrolysis,two-step oxygen production from lunar regolith,and one-step oxygen production from lunar regolith.The two-step methods involve hydrogen reduction,carbothermal reduction,and hydrometallurgy,while the one-step methods encompass fluorination/chlorination,high-temperature decomposition,molten salt electrolysis,and molten regolith electrolysis(MOE).Following a thorough comparison of raw materials,equipment,technology,and economic viability,MOE is identified as the most promising approach for future in-situ oxygen production on the Moon.Considering the corrosion characteristics of molten lunar regolith at high temperatures,along with the Moon's low-gravity environment,the development of inexpensive and stable inert anodes and electrolysis devices that can easily collect oxygen is critical for promoting MOE technology on the Moon.This review significantly contributes to our understanding of in-situ oxygen production technologies on the Moon and supports upcoming lunar exploration initiatives.展开更多
Anion-exchange membrane water electrolyzers(AEMWEs)for green hydrogen production have received intensive attention due to their feasibility of using earth-abundant NiFe-based catalysts.By introducing a third metal int...Anion-exchange membrane water electrolyzers(AEMWEs)for green hydrogen production have received intensive attention due to their feasibility of using earth-abundant NiFe-based catalysts.By introducing a third metal into NiFe-based catalysts to construct asymmetrical M-NiFe units,the d-orbital and electronic structures can be adjusted,which is an important strategy to achieve sufficient oxygen evolution reaction(OER)performance in AEMWEs.Herein,the ternary NiFeM(M:La,Mo)catalysts featured with distinct M-NiFe units and varying d-orbitals are reported in this work.Experimental and theoretical calculation results reveal that the doping of La leads to optimized hybridization between d orbital in NiFeM and 2p in oxygen,resulting in enhanced adsorption strength of oxygen intermediates,and reduced rate-determining step energy barrier,which is responsible for the enhanced OER performance.More critically,the obtained NiFeLa catalyst only requires 1.58 V to reach 1 A cm^(−2) in an anion exchange membrane electrolyzer and demonstrates excellent long-term stability of up to 600 h.展开更多
Binary composites(ZIF-67/rGO)were synthesized by one-step precipitation method using cobalt nitrate hexahydrate as metal source,2-methylimidazole as organic ligand,and reduced graphene oxide(rGO)as carbon carrier.Then...Binary composites(ZIF-67/rGO)were synthesized by one-step precipitation method using cobalt nitrate hexahydrate as metal source,2-methylimidazole as organic ligand,and reduced graphene oxide(rGO)as carbon carrier.Then Ru3+was introduced for ion exchange,and the porous Ru-doped Co_(3)O_(4)/rGO(Ru-Co_(3)O_(4)/rGO)composite electrocatalyst was prepared by annealing.The phase structure,morphology,and valence state of the catalyst were analyzed by X-ray powder diffraction(XRD),scanning electron microscope(SEM),transmission electron microscopy(TEM),and X-ray photoelectron spectroscopy(XPS).In 1 mol·L^(-1)KOH,the oxygen evolution reaction(OER)performance of the catalyst was measured by linear sweep voltammetry,cyclic voltammetry,and chronoamperometry.The results show that the combination of Ru doping and rGO provides a fast channel for collaborative electron transfer.At the same time,rGO as a carbon carrier can improve the electrical conductivity of Ru-Co_(3)O_(4)particles,and the uniformly dispersed nanoparticles enable the reactants to diffuse freely on the catalyst.The results showed that the electrochemical performance of Ru-Co_(3)O_(4)/rGO was much better than that of Co_(3)O_(4)/rGO,and the overpotential of Ru-Co_(3)O_(4)/rGO was 363.5 mV at the current density of 50 mA·cm^(-2).展开更多
This study presents a detailed investigation of the microstructure of the oxygen-deficient perovskite material Ca2FeGaO6-δ using Scanning Electron Microscopy (SEM). The material exhibits significant porosity and irre...This study presents a detailed investigation of the microstructure of the oxygen-deficient perovskite material Ca2FeGaO6-δ using Scanning Electron Microscopy (SEM). The material exhibits significant porosity and irregular grain morphology, with variations in grain size and growth. Unlike conventional perovskite structures, Ca2FeGaO6-δ shows non-uniform grain development, which can be attributed to the presence of oxygen vacancies (δ). SEM analysis reveals that the irregularities in grain size and shape, coupled with the porous nature of the material, are likely to influence its functional properties. These findings provide valuable insights into the structural features of Ca2FeGaO6-δ, offering a foundation for understanding its potential applications in catalysis, sensors, and other technologies. The study highlights the critical role of microstructural characteristics in determining the material’s performance.展开更多
This work aims to study the dependence of the antibacterial activity on the crystal plane of Cu. The generation of reactive oxygen species (ROS) on the thin film of Cu with grains oriented in the plane (100) was evalu...This work aims to study the dependence of the antibacterial activity on the crystal plane of Cu. The generation of reactive oxygen species (ROS) on the thin film of Cu with grains oriented in the plane (100) was evaluated by chemiluminescence (CL). The authors proposed the generation mechanism of these three ROS on the outermost surface consisting of Cu2O thin film, CuO layer and bulk Cu.展开更多
This case report examines the impact of mild hyperbaric oxygen therapy (mHBOT) on cognitive function and symptom relief in a 35-year-old male presenting with concussive symptoms (CS) following a motor vehicle accident...This case report examines the impact of mild hyperbaric oxygen therapy (mHBOT) on cognitive function and symptom relief in a 35-year-old male presenting with concussive symptoms (CS) following a motor vehicle accident (MVA). The patient underwent 10 mHBOT sessions over five weeks (40 minutes per session at 1.5 ATA with 32% oxygen). Post-treatment assessments revealed significant improvements, including an increase in P300 voltage from 4.2 µV to 9.2 µV, aligning with the normative range of 8 - 21 µV. Electroencephalogram (EEG) analysis demonstrated enhanced alpha and theta band activity, reflecting improved cognitive processing and attentional regulation. Clinically, the patient reported reduced headache severity, improved sleep quality, and decreased pain intensity. These findings suggest that mHBOT may support neuroplasticity, mitigate inflammation, and restore cognitive function in patients with CS. Further research, including randomized controlled trials (RCTs), is warranted to validate mHBOT’s efficacy and explore its long-term benefits in traumatic brain injury (TBI) rehabilitation.展开更多
BACKGROUND:Soft tissue damage induced by cobalt nanoparticles is currently the most noticeable complication in patients with artificial joint prostheses.Therefore,an effective therapeutic strategy is needed to limit t...BACKGROUND:Soft tissue damage induced by cobalt nanoparticles is currently the most noticeable complication in patients with artificial joint prostheses.Therefore,an effective therapeutic strategy is needed to limit the toxicity of cobalt nanoparticles.OBJECTIVE:To investigate the protective effect of a ferroptosis inhibitor on cobalt nanoparticles-induced cytotoxicity.METHODS:To evaluate the detoxification effect of ferroptosis inhibitor on mouse fibroblasts(Balb/3T3),Balb/3T3 cells were treated with cobalt nanoparticles and ferroptosis inhibitor for 24 hours.The cell viabilities were measured by cell viability assay.Based on the results of the cell viability assay,the concentrations of cobalt nanoparticles and deferiprone were determined.The experiment was divided into four groups:the cobalt nanoparticles group(400μmol/L cobalt nanoparticles),the cobalt nanoparticles+deferiprone group(400μmol/L cobalt nanoparticles and 25μmol/L deferiprone),the deferiprone group(25μmol/L deferiprone),and the control group.The expressions of glutathione peroxidase 4 and solute carrier family 7 member 11 protein were examined by western blot assay.RESULTS AND CONCLUSION:(1)The cell viability assay results showed that as the exposure time or the drug concentration increased,cell viability decreased further,indicating that the cytotoxic effect of cobalt nanoparticles was time-and dose-dependent.Additionally,after 24 hours of exposure,cobalt nanoparticles significantly reduced cell viability and glutathione levels compared with the control group(P<0.05).At the same time,compared with the control group,there was an increase in reactive oxygen species production,intracellular iron levels,and the expression of inflammatory cytokines such as tumor necrosis factorα,interleukin-1β,and interleukin-6.After the addition of deferiprone,compared with the cobalt nanoparticles group,cell viability significantly improved,and reactive oxygen species production,intracellular iron levels,and the expression of inflammatory cytokines(tumor necrosis factorα,interleukin-1β,and interleukin-6)significantly decreased(P<0.05).This demonstrated that deferiprone had a protective effect on cells exposed to cobalt nanoparticles.(2)Western blot assay results showed that cobalt nanoparticles reduced the expression of glutathione peroxidase 4 and solute carrier family 7 member 11 protein(P<0.05),while deferiprone inhibited this effect(P<0.05).(3)The above findings verify that cobalt nanoparticles are highly cytotoxic and ferroptosis inhibitor deferiprone has a detoxification effect on cytotoxicity induced by cobalt nanoparticles.Ferroptosis plays an important role in the process by which cobalt nanoparticles induce cytotoxicity.The inhibitory effect of ferroptosis inhibitors on the toxicity of cobalt nanoparticles may provide valuable insights for further research into the mechanisms of cobalt nanoparticle toxicity and potential detoxification strategies.展开更多
Climate change impacts soil nitrogen, influencing plant responses to elevated atmospheric [CO2]. Understanding the interaction between nitrogen supply and elevated [CO2] is crucial for predicting plant future performa...Climate change impacts soil nitrogen, influencing plant responses to elevated atmospheric [CO2]. Understanding the interaction between nitrogen supply and elevated [CO2] is crucial for predicting plant future performance. This study examined the interactive effects of elevated [CO2] and nitrogen supply on the eco-physiological performance of yellow birch. Seedlings were exposed to two [CO2] levels and five nitrogen supply levels for 4 months. Growth parameters such as seedling height and root collar diameter increased with higher nitrogen supply and elevated [CO2], while specific leaf area decreased. [CO2] elevation and increasing nitrogen supply also increased the total and stem, and leaf biomass. The elevated [CO2] increased the stem mass ratio but decreased the root-to-shoot ratio and root mass ratio. However, decreases in nitrogen supply increased root mass ratio and root-to-shoot ratio. The elevated [CO2] increased the maximum rate of Rubisco carboxylation (Vcmax) and photosynthetic electron transport (Jmax), but the effect on Jmax was statistically significant only at the two highest nitrogen supply levels. The results indicate that yellow birch may increase photosynthetic capacity, biomass, and growth in the future when [CO2] is higher.展开更多
The nitrogen-coordinated metal single-atom catalysts(M−N−C SACs)with an ultra-high metal loading synthetized by direct high-temperature pyrolysis have been widely reported.However,most of metal single atoms in these c...The nitrogen-coordinated metal single-atom catalysts(M−N−C SACs)with an ultra-high metal loading synthetized by direct high-temperature pyrolysis have been widely reported.However,most of metal single atoms in these catalysts were buried in the carbon matrix,resulting in a low metal utilization and inaccessibility for adsorption of reactants during the catalytic process.Herein,we reported a facile synthesis based on the hard-soft acid-base(HSAB)theory to fabricate Co single-atom catalysts with highly exposed metal atoms ligated to the external pyridinic-N sites of a nitrogen-doped carbon support.Benefiting from the highly accessible Co active sites,the prepared Co−N−C SAC exhibited a superior oxygen reduction reactivity comparable to that of the commercial Pt/C catalyst,showing a high turnover frequency(TOF)of 0.93 e^(−)·s^(-1)·site^(-1)at 0.85 V vs.RHE,far exceeding those of some representative SACs with a ultra-high metal content.This work provides a rational strategy to design and prepare M−N−C single-atom catalysts featured with high site-accessibility and site-density.展开更多
基金Project supported by the National Key R&D Program of China (Grant Nos. 2018YFB0406502, 2017YFF0210800, and 2017YFB0403003)the National Natural Science Foundation of China (Grant Nos. 61974059, 61674077, and 61774081)+1 种基金the Natural Science Foundation of Jiangsu Province (Grant No. BK20160065)the Fundamental Research Funds for the Central Universities。
文摘Regulation with nitrogen and oxygen co-doping on growth and properties of boron doped diamond films is studied by using laughing gas as dopant. As the concentration of laughing gas(N2O/C) increases from 0 to 10%, the growth rate of diamond film decreases gradually, and the nitrogen-vacancy(NV) center luminescence intensity increases first and then weakens. The results show that oxygen in laughing gas has a strong inhibitory effect on formation of NV centers, and the inhibitory effect would be stronger as the concentration of laughing gas increases. As a result, the film growth rate and nitrogen-related compensation donor decrease, beneficial to increase the acceptor concentration(~3.2×10^(19)cm^(-3)) in the film. Moreover, it is found that the optimal regulation with the quality and electrical properties of boron doped diamond films could be realized by adding appropriate laughing gas, especially the hole mobility(~700cm^(2)/V·s), which is beneficial to the realization of high-quality boron doped diamond films and high-level optoelectronic device applications in the future.
文摘Radiation induced reactive oxygen/nitrogen species (ROS/RNS) are reported to cause lung injuries such as pneumonitis and fibrosis which may be fatal at times. Current study is designed to analyse the radioprotective efficacy of P. hexandrum active principles (G-002M) on lungs of mice exposed to high dose of gamma irradiation (7 Gy). Cellular profiles and inflammatory cell infiltrates of irradiated bronchoalveolar lavage fluid (BALF) have shown correlations with lung pathology. Cell counts were determined in BALF of control, 7 Gy radiation exposed and radiation with G-002M pretreated mice. ROS/Nitric Oxide (NO) production was measured by 2,7?dichlorodihydrofluorescein diacetate (DCF-DA) and diaminofluorescein diacetate (DAF-2DA) through microscopy and flow cytometry respectively. Immunostaining of inducible nitric oxide synthase (iNOS) in BALF cells and lung sections was also observed microscopically. iNOS ex- pression was observed in lungs by western blotting. BALF was also processed to estimate total protein, LDH, and phospholipids content. Catalase, reduced Glutathione (GSH), Glutathione reductase (GR) and lipid peroxidation were estimated in lung tissues. Pre-administration of G-002M significantly decreased radiation mediated neutrophils count in BALF of irradiated mice. ROS generation, iNOS expression, total protein, LDH and phospholipids were found less affected in G-002M pretreated group in comparison to radiation alone group. Radiation exposure to mice was found apparently leading to parenchymal fibrosis, an architectural distortion of the lung tissue with edema, infiltration of inflammatory blood cells with increased immunolabeling of iNOS. G-002M pretreatment significantly countered radiation mediated increased lipid peroxidation and decreased GR, catalase and GSH in mice. Current study demonstrates possible role of P. hexandrum (G-002M) in minimizing lung damage induced by radiation mediated ROS/RNS generation.
基金This study was financially supported by the National Natural Science Foundation of China(Grant/Award Number:22232004,22272179,21972068,and 22072067).
文摘Rational design and construction of oxygen reduction reaction(ORR)electrocatalysts with high activity,good stability,and low price are essential for the practical applications of renewable energy conversion devices,such as metal-air batteries.Electronic modification through constructing metal/semiconductor Schottky heterointerface represents a powerful strategy to enhance the electrochemical performance.Herein,we demonstrate a concept of Schottky electrocatalyst composed of uniform Co nanoparticles in situ anchored on the carbon nanotubes aligned on the carbon nanosheets(denoted as Co@N-CNTs/NSs hereafter)toward ORR.Both experimental findings and theoretical simulation testify that the rectifying contact could impel the voluntary electron flow from Co to N-CNTs/NSs and create an internal electric field,thereby boosting the electron transfer rate and improving the intrinsic activity.As a consequence,the Co@N-CNTs/NSs deliver outstanding ORR activity,impressive long-term durability,excellent methanol tolerance,and good performance as the air-cathode in the Zn-air batteries.The design concept of Schottky contact may provide the innovational inspirations for the synthesis of advanced catalysts in sustainable energy conversion fields.
基金The Zhejiang Provincial Natural Science Foundation of China under contract No.LZ22D060002the Key R&D Program of Zhejiang under contract No.2022C03044the National Key Research and Development Program of China under contract No.2021YFC3101702。
文摘Eutrophication caused by inputs of excess nitrogen(N) has become a serious environmental problem in Hangzhou Bay(China),but the sources of this nitrogen are not well understood.In this study,the August 2019 distributions of salinity,nutrients [nitrate(NO_(3)^(-)),nitrite,ammonium,and phosphate],and the stable isotopic composition of NO_(3)^(-)(δ^(15)N and δ^(18)O) were used to investigate sources of dissolved inorganic nitrogen(DIN) to Hangzhou B ay.Spatial distributions of nitrate,salinity,and nitrate δ^(18)O indicate that the Qiantang River,the Changjiang River,and nearshore coastal waters may all contribute nitrate to the bay.Based on the isotopic compositions of nitrate in these potential source waters and conservative mixing of nitrate in our study area,we suggest that the NO_(3)^(- )in Hangzhou B ay was likely derived mainly from soils,synthetic N fertilizer,and manure and sewage.End-member modeling indicates that in the upper half of the bay,the Qiantang River was a very important DIN source,possibly contributing more than 50% of DIN in the bay head area.In the lower half of the bay,DIN was sourced mainly from strongly intruding coastal water.DIN coming directly from the Changjiang River made a relatively small contribution to Hangzhou Bay DIN in August 2019.
基金finically supported by the National Natural Science Foundation of China(22075055)the Guangxi Science and Technology Project(AB16380030)。
文摘Transition metal-nitrogen-carbon(M-N-C)as a promising substitute for the conventional noble metalbased catalyst still suffers from low activity and durability for oxygen reduction reaction(ORR)in proton exchange membrane fuel cells(PEMFCs).To tackle the issue,herein,a new type of sulfur-doped ironnitrogen-hard carbon(S-Fe-N-HC)nanosheets with high activity and durability in acid media were developed by using a newly synthesized precursor of amide-based polymer with Fe ions based on copolymerizing two monomers of 2,5-thiophene dicarboxylic acid(TDA)as S source and 1,8-diaminonaphthalene(DAN)as N source via an amination reaction.The as-synthesized S-Fe-N-HC features highly dispersed atomic Fe Nxmoieties embedded into rich thiophene-S doped hard carbon nanosheets filled with highly twisted graphite-like microcrystals,which is distinguished from the majority of M-N-C with soft or graphitic carbon structures.These unique characteristics endow S-Fe-N-HC with high ORR activity and outstanding durability in 0.5 M H_(2)SO_(4).Its initial half-wave potential is 0.80 V and the corresponding loss is only 21 m V after 30,000 cycles.Meanwhile,its practical PEMFC performance is a maximum power output of 628.0 mW cm^(-2)and a slight power density loss is 83.0 m W cm^(-2)after 200-cycle practical operation.Additionally,theoretical calculation shows that the activity of Fe Nxmoieties on ORR can be further enhanced by sulfur doping at meta-site near FeN_(4)C.These results evidently demonstrate that the dual effect of hard carbon substrate and S doping derived from the precursor platform of amid-polymers can effectively enhance the activity and durability of Fe-N-C catalysts,providing a new guidance for developing advanced M-N-C catalysts for ORR.
基金financially supported by the Outstanding Youth Scientific Research Project for Colleges and Universities of Anhui Province of China (2022AH020054)the Anhui Provincial Natural Science Foundation (2208085Y06)+2 种基金the National Natural Science Foundation of China (Nos.21975001 and U2002213)the Support Program of Excellent Young Talents in Anhui Provincial Colleges and Universities (gxyq ZD2022034)the Double Tops Joint Fund of the Yunnan Science and Technology Bureau and Yunnan University (2019FY003025)。
文摘The interaction between metal and support is critical in oxygen catalysis as it governs the charge transfer between these two entities,influences the electronic structures of the supported metal,affects the adsorption energies of reaction intermediates,and ultimately impacts the catalytic performance.In this study,we discovered a unique charge transfer reversal phenomenon in a metal/carbon nanohybrid system.Specifically,electrons were transferred from the metal-based species to N-doped carbon,while the carbon support reciprocally donated electrons to the metal domain upon the introduction of nickel.This led to the exceptional electrocatalytic performances of the resulting Ni-Fe/Mo_(2)C@nitrogen-doped carbon catalyst,with a half-wave potential of 0.91 V towards oxygen reduction reaction(ORR)and a low overpotential of 290 m V at 10 mA cm^(-2)towards oxygen evolution reaction(OER)under alkaline conditions.Additionally,the Fe-Ni/Mo_(2)C@carbon heterojunction catalyst demonstrated high specific capacity(794 mA h g_(Zn)~(-1))and excellent cycling stability(200 h)in a Zn-air battery.Theoretical calculations revealed that Mo_(2)C effectively inhibited charge transfer from Fe to the support,while secondary doping of Ni induced a charge transfer reversal,resulting in electron accumulation in the Fe-Ni alloy region.This local electronic structure modulation significantly reduced energy barriers in the oxygen catalysis process,enhancing the catalytic efficiency of both ORR and OER.Consequently,our findings underscore the potential of manipulating charge transfer reversal between the metal and support as a promising strategy for developing highly-active and durable bi-functional oxygen electrodes.
基金supported by the Natural Science Foundation of Anhui Province(No.2208085J01 and No.2208085QA28).
文摘Controlling the local electronic structure of active ingredients to improve the adsorption desorption characteristics of oxygen-containing intermediates over the electrochemical liquid-solid interfaces is a critical challenge in the field of oxygen reduction reaction(ORR)catalysis.Here,we offer a simple approach for modulating the electronic states of metal nanocrystals by bimetal co-doping into carbon-nitrogen substrate,allowing us to modulate the electronic structure of catalytic active centers.To test our strategy,we designed a typical bimetallic nanoparticle catalyst(Fe-Co NP/NC)to flexibly alter the reaction kinetics of ORR.Our results from synchrotron Xray absorption spectroscopy and X-ray photoelectron spectroscopy showed that the co-doping of iron and cobalt could optimize the intrinsic charge distribution of Fe-Co NP/NC catalyst,promoting the oxygen reduction kinetics and ultimately achieving remarkable ORR activity.Consequently,the carefully designed Fe-Co NP/NC exhibits an ultra-high kinetic current density at the operating voltage(71.94 mA/cm^(2)at 0.80 V),and the half-wave potential achieves 0.915 V,which is obviously better than that of the corresponding controls including Fe NP/NC,Co NP/NC.Our findings provide a unique perspective for optimizing the electronic structure of active centers to achieve higher ORR catalytic activity and faster kinetics.
基金financially supported by the Joint Funds of the National Natural Science Foundation of China (U20A20280)the Joint Funds of the National Natural Science Foundation of China(U22A20170)。
文摘Metal-free carbon-based materials offer a promising alternative to Pt-based catalysts for the oxygen reduction reaction (ORR).However,challenges persist due to its sluggish kinetics and poor acid ORR performance.Here,we introduce a novel nitrogen-doped porous carbon with rich defects sites (such as pentagons,edge and vacancy defects)(PV/HPC) via a simple etching strategy.The PV/HPC demonstrates long-term stability and exceptional catalytic activity with half-wave potential of 0.9 V and average electron transfer number of 3.98 in alkaline solution while 0.78 V and 3.78 in acidic solution,indicating its efficiency and robustness as an ORR catalyst.Additionally,it achieves a higher kinetic current density of 91.9 m A cm^(-2)at 0.8 V,which is 1.75 times that of Pt/C (52.5 mA cm^(-2)).Furthemore,it enables Al-air battery to attain a maximum power density of 487 mW cm^(-2),compared to 477 mW cm^(-2) for the Pt/C catalyst.Density functional theory (DFT) calculations elucidate that the introduction of multifunctional defects in nitrogen-doped porous carbon collectively reduces the reaction energy barrier of the departure of OH*and boosts the oxygen reduction reaction kinetics.This work presents a simple method to design durable and effective carbon-based ORR catalysts.
基金Research Institute for Smart Energy(CDB2)the grant from the Research Institute for Advanced Manufacturing(CD8Z)+4 种基金the grant from the Carbon Neutrality Funding Scheme(WZ2R)at The Hong Kong Polytechnic Universitysupport from the Hong Kong Polytechnic University(CD9B,CDBZ and WZ4Q)the National Natural Science Foundation of China(22205187)Shenzhen Municipal Science and Technology Innovation Commission(JCYJ20230807140402006)Start-up Foundation for Introducing Talent of NUIST and Natural Science Foundation of Jiangsu Province of China(BK20230426).
文摘Catalyst–support interaction plays a crucial role in improving the catalytic activity of oxygen evolution reaction(OER).Here we modulate the catalyst–support interaction in polyaniline-supported Ni_(3)Fe oxide(Ni_(3)Fe oxide/PANI)with a robust hetero-interface,which significantly improves oxygen evolution activities with an overpotential of 270 mV at 10 mA cm^(-2)and specific activity of 2.08 mA cm_(ECSA)^(-2)at overpotential of 300 mV,3.84-fold that of Ni_(3)Fe oxide.It is revealed that the catalyst–support interaction between Ni_(3)Fe oxide and PANI support enhances the Ni–O covalency via the interfacial Ni–N bond,thus promoting the charge and mass transfer on Ni_(3)Fe oxide.Considering the excellent activity and stability,rechargeable Zn-air batteries with optimum Ni_(3)Fe oxide/PANI are assembled,delivering a low charge voltage of 1.95 V to cycle for 400 h at 10 mA cm^(-2).The regulation of the effect of catalyst–support interaction on catalytic activity provides new possibilities for the future design of highly efficient OER catalysts.
基金financial support of this work by the National Natural Science Foundation of China(Nos.22378332,52003219)the Open Fund of Zhejiang Key Laboratory of Flexible Electronics(No.2022FE008)+1 种基金the Natural Science Foundation of Ningbo(NO.2022J058)Ministry of Industry and Information Technology high quality development project(TC220A04A-206).
文摘Although poly(lactic acid)(PLA)is a good environmentally-friendly bio-degradable polymer which is used to substitute traditional petrochemical-based polymer packaging films,the barrier properties of PLA films are still insufficient for high-barrier packaging applications.In this study,oxygen scavenger hydroxyl-terminated polybutadiene(HTPB)and cobalt salt catalyst were incorporated into the PLA/poly(butylene adipate-co-terephthalate)(PLA/PBAT),followed by melting extrusion and three-layer co-extrusion blown film process to prepare the composite films.The oxygen permeability coefficient of the composite film combined with 6 wt%oxygen scavenger and 0.4 wt%catalyst was decreased significantly from 377.00 cc·mil·m^(-2)·day^(-1)·0.1 MPa^(-1) to 0.98 cc·mil·m^(-2)·day^(-1)·0.1 MPa^(-1),showing a remarkable enhancement of 384.69 times compared with the PLA/PBAT composite film.Meanwhile,the degradation behavior of the composite film was also accelerated,exhibiting a mass loss of nearly 60%of the original mass after seven days of degradation in an alkaline environment,whereas PLA/PBAT composite film only showed a mass loss of 32%.This work has successfully prepared PLA/PBAT composite films with simultaneously improved oxygen barrier property and degradation behavior,which has great potential for high-demanding green chemistry packaging industries,including food,agricultural,and military packaging.
基金financially supported by the National Natural Science Foundation of China(Nos.52404328,52274412,and 52374418)the China Postdoctoral Science Foundation(No.2024M753248)。
文摘The rich resources and unique environment of the Moon make it an ideal location for human expansion and the utilization of extraterrestrial resources.Oxygen,crucial for supporting human life on the Moon,can be extracted from lunar regolith,which is highly rich in oxygen and contains polymetallic oxides.This oxygen and metal extraction can be achieved using existing metallurgical techniques.Furthermore,the ample reserves of water ice on the Moon offer another means for oxygen production.This paper offers a detailed overview of the leading technologies for achieving oxygen production on the Moon,drawing from an analysis of lunar resources and environmental conditions.It delves into the principles,processes,advantages,and drawbacks of water-ice electrolysis,two-step oxygen production from lunar regolith,and one-step oxygen production from lunar regolith.The two-step methods involve hydrogen reduction,carbothermal reduction,and hydrometallurgy,while the one-step methods encompass fluorination/chlorination,high-temperature decomposition,molten salt electrolysis,and molten regolith electrolysis(MOE).Following a thorough comparison of raw materials,equipment,technology,and economic viability,MOE is identified as the most promising approach for future in-situ oxygen production on the Moon.Considering the corrosion characteristics of molten lunar regolith at high temperatures,along with the Moon's low-gravity environment,the development of inexpensive and stable inert anodes and electrolysis devices that can easily collect oxygen is critical for promoting MOE technology on the Moon.This review significantly contributes to our understanding of in-situ oxygen production technologies on the Moon and supports upcoming lunar exploration initiatives.
基金financially supported by the National Natural Science Foundation of China(22309137,22279095)Open subject project State Key Laboratory of New Textile Materials and Advanced Processing Technologies(FZ2023001).
文摘Anion-exchange membrane water electrolyzers(AEMWEs)for green hydrogen production have received intensive attention due to their feasibility of using earth-abundant NiFe-based catalysts.By introducing a third metal into NiFe-based catalysts to construct asymmetrical M-NiFe units,the d-orbital and electronic structures can be adjusted,which is an important strategy to achieve sufficient oxygen evolution reaction(OER)performance in AEMWEs.Herein,the ternary NiFeM(M:La,Mo)catalysts featured with distinct M-NiFe units and varying d-orbitals are reported in this work.Experimental and theoretical calculation results reveal that the doping of La leads to optimized hybridization between d orbital in NiFeM and 2p in oxygen,resulting in enhanced adsorption strength of oxygen intermediates,and reduced rate-determining step energy barrier,which is responsible for the enhanced OER performance.More critically,the obtained NiFeLa catalyst only requires 1.58 V to reach 1 A cm^(−2) in an anion exchange membrane electrolyzer and demonstrates excellent long-term stability of up to 600 h.
文摘Binary composites(ZIF-67/rGO)were synthesized by one-step precipitation method using cobalt nitrate hexahydrate as metal source,2-methylimidazole as organic ligand,and reduced graphene oxide(rGO)as carbon carrier.Then Ru3+was introduced for ion exchange,and the porous Ru-doped Co_(3)O_(4)/rGO(Ru-Co_(3)O_(4)/rGO)composite electrocatalyst was prepared by annealing.The phase structure,morphology,and valence state of the catalyst were analyzed by X-ray powder diffraction(XRD),scanning electron microscope(SEM),transmission electron microscopy(TEM),and X-ray photoelectron spectroscopy(XPS).In 1 mol·L^(-1)KOH,the oxygen evolution reaction(OER)performance of the catalyst was measured by linear sweep voltammetry,cyclic voltammetry,and chronoamperometry.The results show that the combination of Ru doping and rGO provides a fast channel for collaborative electron transfer.At the same time,rGO as a carbon carrier can improve the electrical conductivity of Ru-Co_(3)O_(4)particles,and the uniformly dispersed nanoparticles enable the reactants to diffuse freely on the catalyst.The results showed that the electrochemical performance of Ru-Co_(3)O_(4)/rGO was much better than that of Co_(3)O_(4)/rGO,and the overpotential of Ru-Co_(3)O_(4)/rGO was 363.5 mV at the current density of 50 mA·cm^(-2).
文摘This study presents a detailed investigation of the microstructure of the oxygen-deficient perovskite material Ca2FeGaO6-δ using Scanning Electron Microscopy (SEM). The material exhibits significant porosity and irregular grain morphology, with variations in grain size and growth. Unlike conventional perovskite structures, Ca2FeGaO6-δ shows non-uniform grain development, which can be attributed to the presence of oxygen vacancies (δ). SEM analysis reveals that the irregularities in grain size and shape, coupled with the porous nature of the material, are likely to influence its functional properties. These findings provide valuable insights into the structural features of Ca2FeGaO6-δ, offering a foundation for understanding its potential applications in catalysis, sensors, and other technologies. The study highlights the critical role of microstructural characteristics in determining the material’s performance.
文摘This work aims to study the dependence of the antibacterial activity on the crystal plane of Cu. The generation of reactive oxygen species (ROS) on the thin film of Cu with grains oriented in the plane (100) was evaluated by chemiluminescence (CL). The authors proposed the generation mechanism of these three ROS on the outermost surface consisting of Cu2O thin film, CuO layer and bulk Cu.
文摘This case report examines the impact of mild hyperbaric oxygen therapy (mHBOT) on cognitive function and symptom relief in a 35-year-old male presenting with concussive symptoms (CS) following a motor vehicle accident (MVA). The patient underwent 10 mHBOT sessions over five weeks (40 minutes per session at 1.5 ATA with 32% oxygen). Post-treatment assessments revealed significant improvements, including an increase in P300 voltage from 4.2 µV to 9.2 µV, aligning with the normative range of 8 - 21 µV. Electroencephalogram (EEG) analysis demonstrated enhanced alpha and theta band activity, reflecting improved cognitive processing and attentional regulation. Clinically, the patient reported reduced headache severity, improved sleep quality, and decreased pain intensity. These findings suggest that mHBOT may support neuroplasticity, mitigate inflammation, and restore cognitive function in patients with CS. Further research, including randomized controlled trials (RCTs), is warranted to validate mHBOT’s efficacy and explore its long-term benefits in traumatic brain injury (TBI) rehabilitation.
文摘BACKGROUND:Soft tissue damage induced by cobalt nanoparticles is currently the most noticeable complication in patients with artificial joint prostheses.Therefore,an effective therapeutic strategy is needed to limit the toxicity of cobalt nanoparticles.OBJECTIVE:To investigate the protective effect of a ferroptosis inhibitor on cobalt nanoparticles-induced cytotoxicity.METHODS:To evaluate the detoxification effect of ferroptosis inhibitor on mouse fibroblasts(Balb/3T3),Balb/3T3 cells were treated with cobalt nanoparticles and ferroptosis inhibitor for 24 hours.The cell viabilities were measured by cell viability assay.Based on the results of the cell viability assay,the concentrations of cobalt nanoparticles and deferiprone were determined.The experiment was divided into four groups:the cobalt nanoparticles group(400μmol/L cobalt nanoparticles),the cobalt nanoparticles+deferiprone group(400μmol/L cobalt nanoparticles and 25μmol/L deferiprone),the deferiprone group(25μmol/L deferiprone),and the control group.The expressions of glutathione peroxidase 4 and solute carrier family 7 member 11 protein were examined by western blot assay.RESULTS AND CONCLUSION:(1)The cell viability assay results showed that as the exposure time or the drug concentration increased,cell viability decreased further,indicating that the cytotoxic effect of cobalt nanoparticles was time-and dose-dependent.Additionally,after 24 hours of exposure,cobalt nanoparticles significantly reduced cell viability and glutathione levels compared with the control group(P<0.05).At the same time,compared with the control group,there was an increase in reactive oxygen species production,intracellular iron levels,and the expression of inflammatory cytokines such as tumor necrosis factorα,interleukin-1β,and interleukin-6.After the addition of deferiprone,compared with the cobalt nanoparticles group,cell viability significantly improved,and reactive oxygen species production,intracellular iron levels,and the expression of inflammatory cytokines(tumor necrosis factorα,interleukin-1β,and interleukin-6)significantly decreased(P<0.05).This demonstrated that deferiprone had a protective effect on cells exposed to cobalt nanoparticles.(2)Western blot assay results showed that cobalt nanoparticles reduced the expression of glutathione peroxidase 4 and solute carrier family 7 member 11 protein(P<0.05),while deferiprone inhibited this effect(P<0.05).(3)The above findings verify that cobalt nanoparticles are highly cytotoxic and ferroptosis inhibitor deferiprone has a detoxification effect on cytotoxicity induced by cobalt nanoparticles.Ferroptosis plays an important role in the process by which cobalt nanoparticles induce cytotoxicity.The inhibitory effect of ferroptosis inhibitors on the toxicity of cobalt nanoparticles may provide valuable insights for further research into the mechanisms of cobalt nanoparticle toxicity and potential detoxification strategies.
文摘Climate change impacts soil nitrogen, influencing plant responses to elevated atmospheric [CO2]. Understanding the interaction between nitrogen supply and elevated [CO2] is crucial for predicting plant future performance. This study examined the interactive effects of elevated [CO2] and nitrogen supply on the eco-physiological performance of yellow birch. Seedlings were exposed to two [CO2] levels and five nitrogen supply levels for 4 months. Growth parameters such as seedling height and root collar diameter increased with higher nitrogen supply and elevated [CO2], while specific leaf area decreased. [CO2] elevation and increasing nitrogen supply also increased the total and stem, and leaf biomass. The elevated [CO2] increased the stem mass ratio but decreased the root-to-shoot ratio and root mass ratio. However, decreases in nitrogen supply increased root mass ratio and root-to-shoot ratio. The elevated [CO2] increased the maximum rate of Rubisco carboxylation (Vcmax) and photosynthetic electron transport (Jmax), but the effect on Jmax was statistically significant only at the two highest nitrogen supply levels. The results indicate that yellow birch may increase photosynthetic capacity, biomass, and growth in the future when [CO2] is higher.
基金supported by Shanxi Province Science Foundation for Youths(202203021212300)Taiyuan University of Science and Technology Scientific Research Initial Funding(20212064)Outstanding Doctoral Award Fund in Shanxi Province(20222060).
文摘The nitrogen-coordinated metal single-atom catalysts(M−N−C SACs)with an ultra-high metal loading synthetized by direct high-temperature pyrolysis have been widely reported.However,most of metal single atoms in these catalysts were buried in the carbon matrix,resulting in a low metal utilization and inaccessibility for adsorption of reactants during the catalytic process.Herein,we reported a facile synthesis based on the hard-soft acid-base(HSAB)theory to fabricate Co single-atom catalysts with highly exposed metal atoms ligated to the external pyridinic-N sites of a nitrogen-doped carbon support.Benefiting from the highly accessible Co active sites,the prepared Co−N−C SAC exhibited a superior oxygen reduction reactivity comparable to that of the commercial Pt/C catalyst,showing a high turnover frequency(TOF)of 0.93 e^(−)·s^(-1)·site^(-1)at 0.85 V vs.RHE,far exceeding those of some representative SACs with a ultra-high metal content.This work provides a rational strategy to design and prepare M−N−C single-atom catalysts featured with high site-accessibility and site-density.
