Membrane technology has become the mainstream process for the production of electronic grade hydrogen peroxide(H_(2)O_(2)).But due to the oxidation degradation of the organic membranes(e.g.polyamide)by the strong oxid...Membrane technology has become the mainstream process for the production of electronic grade hydrogen peroxide(H_(2)O_(2)).But due to the oxidation degradation of the organic membranes(e.g.polyamide)by the strong oxidative radicals(e.g.OH)generated via the activation of H_(2)O_(2)by iron ions(Fe^(3+)),the short effective lifetime of membranes remains a challenge.Inorganic nano tin oxide(SnO_(2))has great potential for the removal of Fe^(3+)in strongly oxidative H_(2)O_(2)because of its ability to stabilize H2O_(2)and preferentially adsorb Fe^(3+).Herein,we have designed for the first time a flower-like robust SnO_(2)membrane on the ceramic support by in situ template-free one-step hydrothermal method.The three-dimensional loose pore structure in the membrane built by interlacing SnO_(2)nanosheets endows the SnO_(2)membrane with a high specific surface area and abundant adsorption sites(AOH).Based on the coordination complexation and electrostatic attraction between the SnO_(2)surface and Fe^(3+),the membrane shows a high Fe3+removal efficiency(83%)and permeability(24 L·m^(-2)·h^(-1)·MPa^(-1))in H_(2)O_(2).This study provides an innovative and simple approach to designing robust SnO_(2)membranes for highly efficient removal of Fe^(3+)in harsh environments,such as strong oxidation conditions.展开更多
In this study,the perovskite nanocomposite PrFe_(x)Co_(1-x)O_(3)(Pr(S))was successfully synthesized by the sol-gel method;PrFe_(x)Co_(1-x)O_(3)/Al-pillared montmorillonite(Pr(S)/Mt)catalysts were prepared by impregnat...In this study,the perovskite nanocomposite PrFe_(x)Co_(1-x)O_(3)(Pr(S))was successfully synthesized by the sol-gel method;PrFe_(x)Co_(1-x)O_(3)/Al-pillared montmorillonite(Pr(S)/Mt)catalysts were prepared by impregnation(D)method and solid-melting(G)method,respectively,with Pr(S)as the active component and Al-pillared montmorillonite as the carrier.The catalysts were applied to treat the 2-hydroxybenzoic acid(2-HA)-simulated wastewater by catalytic wet peroxide oxidation(CWPO)technique,and the chemical oxygen demand(COD)removal rate and the 2-HA degradation rate were used as indicators to evaluate the catalytic performance.The results of the experiment indicated that the solid-melting method was more conducive to preparing the catalyst when the Co/Fe molar ratio of 7:3 and the optimal structural properties of the catalysts were achieved.The influence of operating parameters,including reaction temperature,catalyst dosage,H_(2)O_(2)dosage,pH,and initial 2-HA concentration,were optimized for the degradation of 2-HA by CWPO.The results showed that 97.64%of 2-HA degradation and 75.23%of COD removal rate were achieved under more suitable experimental conditions.In addition,after the catalyst was used five times,the degradation rate of 2-HA could still reach 76.93%,which implied the high stability and reusability of the catalyst.The high catalytic activity of the catalyst was due to the doping of Co into PrFeO_(3),which could promote the generation of HO·,and the high stability could be attributed to the loading of Pr(S)onto Al-Mt,which reduced the leaching of reactive metals.The study of reaction mechanism and kinetics showed that the whole degradation process conformed to the pseudo-firstorder kinetic equation,and the Langmuir-Hinshelwood method was applied to demonstrate that catalysis was dominant in the degradation process.展开更多
Norovirus(NoV)is regarded as one of the most common causes of foodborne diarrhea in the world.It is urgent to identify the pathogenic microorganism of the diarrhea in short time.In this work,we developed an electroche...Norovirus(NoV)is regarded as one of the most common causes of foodborne diarrhea in the world.It is urgent to identify the pathogenic microorganism of the diarrhea in short time.In this work,we developed an electrochemical and colorimetric dual-mode detection for NoV based on the excellent dual catalytic properties of copper peroxide/COF-NH_(2)nanocomposite(CuO_(2)@COF-NH_(2)).For the colorimetric detection,NoV can be directly detected by the naked eye based on CuO_(2)@COF-NH_(2)as a laccase-like nonazyme using“peptide-NoV-antibody”recognition mode.The colorimetric assay displayed a wide and quality linear detection range from 1 copy/mL to 5000 copies/mL of NoV with a low limit of detection(LOD)of 0.125 copy/mL.For the electrochemical detection of NoV,CuO_(2)@COF-NH_(2)showed an oxidation peak of copper ion from Cu^(+)to Cu^(2+)using“peptide-NoV-antibody”recognition mode.The electrochemical assay showed a linear detection range was 1-5000 copies/mL with a LOD of 0.152 copy/mL.It's worthy to note that this assay does not need other electrical signal molecule,which provide the stable and sensitive electrochemial detection for NoV.The electrochemical and colorimetric dual-mode detection was used to detect NoV in foods and faceal samples,which has the potential for improving food safety and diagnosing of NoV-infected diarrhea.展开更多
An environmentally benign,sustainable,and cost-effective supply of H_(2)O_(2)as a rapidly expanding consumption raw material is highly desired for chemical industries,medical treatment,and household disinfection.The e...An environmentally benign,sustainable,and cost-effective supply of H_(2)O_(2)as a rapidly expanding consumption raw material is highly desired for chemical industries,medical treatment,and household disinfection.The electrocatalytic production route via electrochemical oxygen reduction reaction(ORR)offers a sustainable avenue for the onsite production of H_(2)O_(2)from O2 and H2O.The most crucial and innovative part of such technology lies in the availability of suitable electrocatalysts that promote two-electron(2e^(–))ORR.In recent years,tremendous progress has been achieved in designing efficient,robust,and cost-effective catalyst materials,including noble metals and their alloys,metalfree carbon-based materials,single-atom catalysts,and molecular catalysts.Meanwhile,innovative cell designs have significantly advanced electrochemical applications at the industrial level.This review summarizes fundamental basics and recent advances in H_(2)O_(2)production via 2e^(–)-ORR,including catalyst design,mechanistic explorations,theoretical computations,experimental evaluations,and electrochemical cell designs.Perspectives on addressing remaining challenges are also presented with an emphasis on the large-scale synthesis of H_(2)O_(2)via the electrochemical route.展开更多
The mercury species in the ocean(MeHg,Hg^(2+))will be enriched in marine organisms and threaten human health through the food chain.While the excessive H_(2)O_(2)in the metabolic process will produce hydroxyl radicals...The mercury species in the ocean(MeHg,Hg^(2+))will be enriched in marine organisms and threaten human health through the food chain.While the excessive H_(2)O_(2)in the metabolic process will produce hydroxyl radicals and accelerate the aging of human cells,causing a series of diseases.Hence,the cost-effective and rapid detection of mercury and H_(2)O_(2)is of urgent requirement and significance.Here,we synthesized emerging graphitic carbon nitride quantum dots(g-CNQDs)with high fluorescence quantum yield(FLQY)of 42.69%via a bottom-up strategy by a facile one-step hydrothermal method.The g-CNQDs can detect the H_(2)O_(2)and Hg^(2+)through the fluorescence quenching effect between g-CNQDs and detected substances.With the presence of KI,g-CNQDs show concentration-dependent fluorescence toward H_(2)O_(2),with a wide detection range of 1–1000μmolL^(-1)and a low detection limit of 0.23μmolL^(-1).The g-CNQDs also show sensitivity toward Hg^(2+)with a detection range of 0–0.1μmolL^(-1)and a detection limit of 0.038μmolL^(-1).This dual-function detection of g-CNQDs has better practical application capability compared to other quantum dot detection.This study may provide a new strategy for g-CNQDs preparation and construct a fluorescence probe that can be used in various systems involving H_(2)O_(2)and Hg^(2+),providing better support for future bifunctional or multifunction studies.展开更多
Enargite is typically associated with chalcocite.Owing to the similarity in the flotation behaviors of these minerals,both minerals are reported to concentrate in the conventional flotation circuit.However,inorganic a...Enargite is typically associated with chalcocite.Owing to the similarity in the flotation behaviors of these minerals,both minerals are reported to concentrate in the conventional flotation circuit.However,inorganic arsenic in enargite can decrease the copper concentrate quality and increase the operating cost of processing this concentrate.Separating these minerals is important for cleaner copper production to avoid these effects.In this context,this study investigated the effect of hydrogen peroxide(H_(2)O_(2))treatment on the flotation behavior of chalcocite and enargite.Flotation tests of pure and mixed minerals indicated that H_(2)O_(2)treatment reduced the floatability of chalcocite and enargite by forming sulfate and copper hydroxide on their surfaces.Despite the detrimental effect of the H_(2)O_(2)treatment,there was a narrow window of H_(2)O_(2)concentration for separating both minerals,in which enargite floated and chalcocite was depressed.This selective flotation behavior was caused by the rapid adsorption of potassium amyl xanthate(KAX)and lower surface oxidation of enargite compared with that of chalcocite.展开更多
Copper was extracted from methylchlorosilane slurry residue by a direct hydrogen peroxide leaching method.A number of experimental parameters were analyzed to determine the extraction efficiency of copper.The extracti...Copper was extracted from methylchlorosilane slurry residue by a direct hydrogen peroxide leaching method.A number of experimental parameters were analyzed to determine the extraction efficiency of copper.The extraction efficiency of copper reached 98.5%under the optimal leaching conditions,such as the hydrogen peroxide concentration of 1.875 mol·L^(-1),the leaching temperature of 323 K,the liquid–solid ratio of 20 ml·g^(-1),and the stirring speed of 300 r·min^(-1).The leaching kinetics of the copper extraction process was then described by the shrinking core model.There were two stages.The first stage was controlled by chemical reactions,while the second stage was controlled by interface transfer and product layer diffusion.The activation energy and kinetic control equations were determined,as well as an explanation of the leaching mechanism of copper extraction based on kinetic analysis and materials characterization.Copper resources can be recovered from the methylchlorosilane slurry residue efficiently and inexpensively with the methods used in this study.展开更多
It is of great interest to develop the novel transition metal-based electrocatalysts with high selectivity and activity for two electron oxygen reduction reaction(2e^(-) ORR).Herein,the nickel ditelluride(NiTe_(2)) wi...It is of great interest to develop the novel transition metal-based electrocatalysts with high selectivity and activity for two electron oxygen reduction reaction(2e^(-) ORR).Herein,the nickel ditelluride(NiTe_(2)) with layered structure was explored as the 2e^(-) ORR electrocatalyst,which not only showed the highest 2e^(-) selectivity more than 97%,but also delivered a slight activity decay after 5000 cycles in alkaline media.Moreover,when NiTe_(2) was assembled as the electrocatalyst in H-type electrolyzer,the on-site yield of H_(2)O_(2) could reach up to 672 mmol h^(-1)g^(-1) under 0.45 V vs.RHE.Further in situ Raman spectra,theoretical calculation and post microstructural analysis synergistically unveiled that such a good 2e^(-) ORR performance could be credited to the intrinsic layered crystal structure,the high compositional stability,as well as the electron modulation on the active site Ni atoms by neighboring Te atoms,leading to the exposure of active sites as well as the optimized adsorption free energy of Ni to –OOH.More inspiringly,such telluride electrocatalyst has also been demonstrated to exhibit high activity and selectivity towards 2e^(-) ORR in neutral media.展开更多
A series of CoPd/KIT-6 bimetallic catalysts with various Co:Pd molar ratios at different calcination temperatures were prepared and used for the direct synthesis of H_(2)O_(2) from H_(2) and O_(2).These catalysts were...A series of CoPd/KIT-6 bimetallic catalysts with various Co:Pd molar ratios at different calcination temperatures were prepared and used for the direct synthesis of H_(2)O_(2) from H_(2) and O_(2).These catalysts were characterized by nitrogen adsorption-desorption,low and wide-angle X-ray diffraction(XRD),X-ray photoelectron spectroscopy(XPS),transmission electron microscopy(TEM),scanning electron microscopy(SEM),elemental mapping and energy-dispersive X-ray(EDX)methods.It was found that the particle size,electronic interactions,morphology,and textural properties of these catalysts as well as their catalytic activity in the reaction of H_(2) with O_(2) were affected by Co addition and different calcination temperatures.Also,the results showed that while the H_(2)O_(2) selectivity depends on Pd^(2+) species,the H_(2) conversion is related to Pd0 active sites.Among these catalysts,CoPd/KIT-6 calcined at 350℃(CoPd/KIT-350 catalyst)showed the best catalytic activity with 50%of H_(2)O_(2) selectivity and 51%conversion of H_(2).展开更多
Platinum-based materials show excellent electrocatalytic performance and have good potential for use in fuel cells.However,the high cost and scarce reserves have restricted their wide application.Therefore,it is a cha...Platinum-based materials show excellent electrocatalytic performance and have good potential for use in fuel cells.However,the high cost and scarce reserves have restricted their wide application.Therefore,it is a challenging task to reduce the amount of Pt as well as ensure good catalytic performance.Herein,anchoring of Pt single atoms(0.21 wt‰)with ultra-low content on g-C_(3)N_(4)nanosheets(Pt_(0.21)/CN)has been successfully achieved.The obtained Pt_(0.21)/CN catalyst shows excellent two-electron oxygen reduction(2e-ORR)capability for hydrogen peroxide(H_(2)O_(2)).Compared with CN,its H_(2)O_(2)selectivity increased from 80%to 98%in 0.1M KOH,surpassing those in most of the reported studies.Besides,the H_(2)O_(2)production rate of Pt_(0.21)/CN is 767 mmol gcat^(-1)h-1,which is 11.1 times that of CN.This work may pave the way toward the development of an effective method for the design of noblemetal electrocatalysts with low metal loading and high catalytic activity.展开更多
Seborrheic keratosis has a varying degree of pigmentation. In pigmented seborrheic keratosis, the proliferating keratinocytes trigger the activation of neighboring melanocytes by secreting melanocyte-stimulating cytok...Seborrheic keratosis has a varying degree of pigmentation. In pigmented seborrheic keratosis, the proliferating keratinocytes trigger the activation of neighboring melanocytes by secreting melanocyte-stimulating cytokines. The etiology of seborrheic keratosis is not known. Epidermal growth factors or their receptors have been implicated in the development of seborrheic keratosis. Seborrheic keratoses can safely be left alone, but ugly or easily traumatized ones can be removed with cryotherapy, electrodesiccation, curettage, or shave excision. The present work aims to compare two modalities of treatment for seborrheic keratosis, namely cryotherapy and hydrogen peroxide (30%). Methods: 30 patients with seborrheic keratosis were included in this study. They were divided into two groups, each with 15 patients. The treatment modalities that have been used include cryotherapy and hydrogen peroxide in three different concentrations (30%, 35%, and 40%). Result: The cryotherapy group consisted of 15 patients, 7 males and 8 females. Their ages ranged from 38 to 80 years, with a mean of 56.1 ± 11.4. Clinical and photographic assessments showed complete removal in all 15 patients in this group (100%). As regards the hydrogen peroxide group, this group included 15 patients, distributed among 7 males and 8 females. Their ages ranged from 39 to 90 years, with a mean of 53.9 ± 14.4. Clinical and photographic assessments showed response in only one small superficial lesion in one patient (6.7%) and no response in 14 patients (93.3%). Conclusion: Cryotherapy is an effective, easy, and relatively cheap method for treating seborrheic keratosis.展开更多
In this study,an amine-coordinated cobalt phthalocyanine(CoPc)-based anodic catalyst was fabricated by a facile process,to enhance the performance of hydrogen peroxide fuel cells(HPFCs) and enzymatic biofuel cells(EBC...In this study,an amine-coordinated cobalt phthalocyanine(CoPc)-based anodic catalyst was fabricated by a facile process,to enhance the performance of hydrogen peroxide fuel cells(HPFCs) and enzymatic biofuel cells(EBCs).For this purpose,polyethyleneimine(PEI) was added onto the reduced graphene oxide and CoPc composite(RGO/CoPc) to create abundant NH2 axial ligand groups,for anchoring the Co core within the CoPc.Owing to the PEI addition,the onset potential of the hydrogen peroxide oxidation reaction was shifted by 0.13 V in the negative direction(0.02 V) and the current density was improved by 1.92 times(1.297 mA cm^(-2)),compared to those for RGO/CoPc(0.15 V and 0.676 mA cm^(-2),respectively),due to the formation of donor-acceptor dyads and the prevention of CoPc from leaching out.The biocatalyst using glucose oxidase(GOx)([RGO/CoPc]/PEI/GOx) showed a better onset potential and catalytic activity(0.15 V and 318.7 μA cm^(-2)) than comparable structures,as well as significantly improved operational durability and long-term stability.This is also attributed to PEI,which created a favorable microenvironment for the enzyme.The maximum power densities(MPDs) and open-circuit voltages(OCVs) obtained for HPFCs and EBCs using the suggested catalyst were 105.2±1.3 μW cm^(-2)(0.317±0.003 V) and 25.4±0.9 μW cm^(-2)(0.283±0.007 V),respectively.This shows that the amine axial ligand effectively improves the performance of the actual driving HPFCs and EBCs.展开更多
In the present paper, blood lipids peroxide(LPO) level and activities of glutathione peroxidase(GSH-Px) and superoxide dismutase(SOD) were investigated before and after combined treatment of acupuncture and moxibustio...In the present paper, blood lipids peroxide(LPO) level and activities of glutathione peroxidase(GSH-Px) and superoxide dismutase(SOD) were investigated before and after combined treatment of acupuncture and moxibustion and Chinese drugs in patients of vascular dementia(VD), and their results were compared with those in healthy persons with the similar ages to the patients. The results showed that the blood LPO level increased significantly, and the activities of SOD and GSH-Px reduced significantly in patients of VD as compared with those in the control group. Degrees of patient’s condition were related with amplitudes of the increase of LPO and the reduction of activities of GSHPx and SOD. Combined treatment of acupuncture and moxibustion and Chinese drugs could raise markedly activitles of blood GSH-Px and SOD, and lowered LPO level in the patients of VD, which are related to clinical therapeutic effects. It is considered that combination of acupuncture and moxibustion with Chinese drugs can increase the action of the antiperoxidative system in the patients of VD, exerting anti-peroxidative ability and clearing LPO and reducing the oxidative injury of the organism by oxygen free radical, which is one of mechanisms of combined treatment of acupuncture and moxibustion with Chinese drugs.展开更多
The level of lipid peroxides (LPO) and copper-zinc containing superoxide dismutase (SOD-Ⅰ) in the gastric mucosa and serum was determined in 141 samples from 25 patients after con-ventional subtotal gastrectomy (11 c...The level of lipid peroxides (LPO) and copper-zinc containing superoxide dismutase (SOD-Ⅰ) in the gastric mucosa and serum was determined in 141 samples from 25 patients after con-ventional subtotal gastrectomy (11 cases of Billroth Ⅰ and 14 cases of Billroth Ⅱ) and 11 patientsafter pylorus and antroseromuscular flap preserving gastrectomy (PAFPG).Those of 11 normal subjects were examined likewise to serve as control.It was found that:(1) The average LPO levelwas much higher and the average SOD-Ⅰ level much lower in the gastric mucosa of the patientsafter conventional subtotal gastrectomy especially the Billroth Ⅱ type than in that of those afterPAFPG.(2) In 36 specimens of stump mucosa,the average LPO level was significantly higher inthe tissue around the anastomotic ring than in that of the body of the stump;no marked differ-ence of SOD-Ⅰ level between the 2 was revealed.(3) The LPO value in the stump mucosa waspositively correlated to and the SOD-Ⅰ value negatively correlated to the pH value of gastric juice.These rindings suggest that the reation of oxygen free radicals in the stump mucosa may be influ-enced by the intragastric pH or by the type of digestive continuity reconstruction,and that thereaction of oxygen free radicals especially the lipid peroxidation may play a role in the pathogenesisof the lesions in the anastomotic stoma.展开更多
Objective:To evaluate the anti-apoptotic and radical scavenging activities of dietary phenolics, namely ascorbic acid,a-tocopherol acetate,citric acid,salicylic acid,and estimate H_2O_2induced apoptosis in renal cell ...Objective:To evaluate the anti-apoptotic and radical scavenging activities of dietary phenolics, namely ascorbic acid,a-tocopherol acetate,citric acid,salicylic acid,and estimate H_2O_2induced apoptosis in renal cell carcinoma cells.Methods:The intracellular antioxidant potency of antioxidants was investigated.H_2O-2-induced apoptosis in RCC-26 was assayed with the following parameters:cell viability(%apoptosis),nucleosomal damage and DNA fragmentation, bcl-2 levels and flow cytometery analysis(ROS production evaluation).Results:Ine anticancer properties of antioxidants such as ascorbic acid,a- tocopherol acetate,citric acid,salicylic acid with perdurable responses were investigated.It was observed that these antioxidants had protective effect(anti-apoptotic activity) against hydrogen peroxide(H_2O_2) in renal cell carcinoma(RCC-26) cell line.Conclusions:This study reveals and proves the anticancer properties.However,in cancer cell lines anti-apoptotic activity can indirectly reflect the cancer promoter activity through radicals scavenging,and significantly protect nucleus and bcl-2.展开更多
Objective:To investigate thein vitroantioxidant potential of Carica papaya(C. papaya) leaf extract and its effect on hydrogen peroxide-induced erythrocyte damage assessed by haemolysis and lipid peroxidation.Methods:H...Objective:To investigate thein vitroantioxidant potential of Carica papaya(C. papaya) leaf extract and its effect on hydrogen peroxide-induced erythrocyte damage assessed by haemolysis and lipid peroxidation.Methods:Hydroxyl radical scavenging activities, hydrogen ion scavenging activity, metal chelating activity, and the ferrous ion reducing ability were assessed as antioxidant indices. In the other experiment, human erythrocytes were treated with hydrogen peroxide to induce erythrocyte damage. The extract(at various concentrations) was subsequently incubated with the erythrocytes and later analysed for haemolysis and lipid peroxidation as indices for erythrocyte damage.Results:Preliminary investigation of the extract showed that the leaf possessed significant antioxidant and free radical scavenging abilities usingin vitro models in a concentration dependent manner(P<0.05). The extract also reduced hydrogen peroxide induced erythrocyte haemolysis and lipid peroxidation significantly when compared with ascorbic acid(P<0.05). The IC50values were 7.33 mg/mL and 1.58 mg/mL for inhibition of haemolysis and lipid peroxidation, respectively. In all cases, ascorbic acid(the reference antioxidant) possessed higher activity than the extract.Conclusions:The findings show that C. papayaleaves possess significant bioactive potential which is attributed to the phytochemicals which act in synergy.Thus, the leaves can be exploited for pharmaceutical and nutritional purposes.展开更多
Alpinia oxyphylla,a traditional herb,is widely used for its neuroprotective,antioxidant and memory-improving effects.However,the neuroprotective mechanisms of action of its active ingredients are unclear.In this study...Alpinia oxyphylla,a traditional herb,is widely used for its neuroprotective,antioxidant and memory-improving effects.However,the neuroprotective mechanisms of action of its active ingredients are unclear.In this study,we investigated the neuroprotective effects of various organic extracts of Alpinia oxyphylla on PC12 cells exposed to hydrogen peroxide-induced oxidative injury in vitro.Alpinia oxyphylla was extracted three times with 95%ethanol(representing extracts 1–3).The third 95%ethanol extract was dried and resuspended in water,and then extracted successively with petroleum ether,ethyl acetate and n-butanol(representing extracts 4–6).The cell counting kit-8 assay and microscopy were used to evaluate cell viability and observe the morphology of PC12 cells.The protective effect of the three ethanol extracts(at tested concentrations of 50,100 and 200μg/mL)against cytotoxicity to PC12 cells increased in a concentration-dependent manner.The ethyl acetate,petroleum ether and n-butanol extracts(each tested at 100,150 and 200μg/mL)had neuroprotective effects as well.The optimum effective concentration ranged from 50–200μg/mL,and the protective effect of the ethyl acetate extract was comparatively robust.These results demonstrate that organic extracts of Alpinia oxyphylla protect PC12 cells against apoptosis induced by hydrogen peroxide.Our findings should help identify the bioactive neuroprotective components in Alpinia oxyphylla.展开更多
Electrochemical synthesis of hydrogen peroxide(H2 O2)provides a clean and safe technology for large-scale H2 O2 production.The core of this project is the development of highly active and highly selective catalysts.Re...Electrochemical synthesis of hydrogen peroxide(H2 O2)provides a clean and safe technology for large-scale H2 O2 production.The core of this project is the development of highly active and highly selective catalysts.Recent studies demonstrate that carbonaceous materials are favorable catalysts because of their low-cost and tunable surface structures.This brief review first summarizes the strategies of carbonaceous material engineering for selective two-electron O2 reduction reaction and discusses potential mechanisms.In addition,several device designs using carbonaceous materials as catalysts for H2 O2 production are introduced.Finally,research directions are proposed for practical application and performance improvement.展开更多
Nitric oxide is now universally recognized as an extracellular signaling molecule. Nitric oxide, produced in one cell, diffuses across the extracellular space and acts with targets in an adjoining cell. In this study,...Nitric oxide is now universally recognized as an extracellular signaling molecule. Nitric oxide, produced in one cell, diffuses across the extracellular space and acts with targets in an adjoining cell. In this study, we present proof that hydrogen peroxide - like nitric oxide - acts as a true first (intercellular) messenger for a multitude of pro-inflammatory ligands. RAW 264.7 macrophages were activated with three different ligands, lipopolysaccharide, interferon-gamma or advanced glycation end products in the presence of increasing concentrations of (hydrogen peroxide scavenging) catalase. As inflammatory readouts, nitric oxide and tumor necrosis factor were determined. We hypothesize that hydrogen peroxide travels between cells propagating the signal, then a certain percentage of the readout should be inhibited by catalase in a concentration- dependent manner. The experiment showed concentration-dependent inhib让ion of nitric oxide and tumor necrosis factor-a production in response to all three ligands/ligand combinations (interferon-gamma, lipopolysaccharide, and chicken egg albumin-derived advanced glycation end product) in the presence of increasing concentration of catalase. For example, catalase inhibited 100% of nitric oxide and 40% of tumor necrosis factor-a production at its highest concentration. Our results suggest that hydrogen peroxide travels through cell membranes into the extracellular space and enters and activates ad;acent cells. Like rdtric oxide, we suggest that it is a ubiquitous first messenger, able to transmit cell-to-cell pro-inflammatory signals such as nitric oxide and tumor necrosis factor-a. In a therapeutic setting, our data suggest that compounds acting as hydrogen peroxide scavengers might not even need to enter the cell to act as anti-inflammatory drugs.展开更多
基金support from the National Key Research and Development Program(2021YFB3801303)the National Natural Science Foundation of China(21838005,21921006)+1 种基金the State Key Laboratory of Materials-Oriented Chemical Engineering(SKL-MCE-22A03)the Key Research and Development Program of Jiangsu Provincial Department of Science and Technology(BE2022033-3).
文摘Membrane technology has become the mainstream process for the production of electronic grade hydrogen peroxide(H_(2)O_(2)).But due to the oxidation degradation of the organic membranes(e.g.polyamide)by the strong oxidative radicals(e.g.OH)generated via the activation of H_(2)O_(2)by iron ions(Fe^(3+)),the short effective lifetime of membranes remains a challenge.Inorganic nano tin oxide(SnO_(2))has great potential for the removal of Fe^(3+)in strongly oxidative H_(2)O_(2)because of its ability to stabilize H2O_(2)and preferentially adsorb Fe^(3+).Herein,we have designed for the first time a flower-like robust SnO_(2)membrane on the ceramic support by in situ template-free one-step hydrothermal method.The three-dimensional loose pore structure in the membrane built by interlacing SnO_(2)nanosheets endows the SnO_(2)membrane with a high specific surface area and abundant adsorption sites(AOH).Based on the coordination complexation and electrostatic attraction between the SnO_(2)surface and Fe^(3+),the membrane shows a high Fe3+removal efficiency(83%)and permeability(24 L·m^(-2)·h^(-1)·MPa^(-1))in H_(2)O_(2).This study provides an innovative and simple approach to designing robust SnO_(2)membranes for highly efficient removal of Fe^(3+)in harsh environments,such as strong oxidation conditions.
基金supported by the Key Research and Development Program of Shaanxi,China(2018GY-067).
文摘In this study,the perovskite nanocomposite PrFe_(x)Co_(1-x)O_(3)(Pr(S))was successfully synthesized by the sol-gel method;PrFe_(x)Co_(1-x)O_(3)/Al-pillared montmorillonite(Pr(S)/Mt)catalysts were prepared by impregnation(D)method and solid-melting(G)method,respectively,with Pr(S)as the active component and Al-pillared montmorillonite as the carrier.The catalysts were applied to treat the 2-hydroxybenzoic acid(2-HA)-simulated wastewater by catalytic wet peroxide oxidation(CWPO)technique,and the chemical oxygen demand(COD)removal rate and the 2-HA degradation rate were used as indicators to evaluate the catalytic performance.The results of the experiment indicated that the solid-melting method was more conducive to preparing the catalyst when the Co/Fe molar ratio of 7:3 and the optimal structural properties of the catalysts were achieved.The influence of operating parameters,including reaction temperature,catalyst dosage,H_(2)O_(2)dosage,pH,and initial 2-HA concentration,were optimized for the degradation of 2-HA by CWPO.The results showed that 97.64%of 2-HA degradation and 75.23%of COD removal rate were achieved under more suitable experimental conditions.In addition,after the catalyst was used five times,the degradation rate of 2-HA could still reach 76.93%,which implied the high stability and reusability of the catalyst.The high catalytic activity of the catalyst was due to the doping of Co into PrFeO_(3),which could promote the generation of HO·,and the high stability could be attributed to the loading of Pr(S)onto Al-Mt,which reduced the leaching of reactive metals.The study of reaction mechanism and kinetics showed that the whole degradation process conformed to the pseudo-firstorder kinetic equation,and the Langmuir-Hinshelwood method was applied to demonstrate that catalysis was dominant in the degradation process.
基金financially supported by National Key Research and Development Program of China(2022YFC2601604)Major science and technology project of Yunnan Province(202202AE090085)+9 种基金the National Natural Science Foundation of China(3216059732160236)Science and technology talent and platform plan of YunnanKey Scientific and Technology Project of Yunnan(202203AC100010)Spring City Plan:the High-level Talent Promotion and Training Project of Kunming(2022SCP001)the second phase of“Double-First Class”program construction of Yunnan Universitygrants from State Key Laboratory for Conservation and Utilization of Bio-Resources in Yunnan,Yunnan University(2021KF005)Key Scientific and Technology Project of Yunnan(202002AE320005)Program for Excellent Young Talents of Yunnan Universitythe Program for Donglu Scholars of Yunnan University。
文摘Norovirus(NoV)is regarded as one of the most common causes of foodborne diarrhea in the world.It is urgent to identify the pathogenic microorganism of the diarrhea in short time.In this work,we developed an electrochemical and colorimetric dual-mode detection for NoV based on the excellent dual catalytic properties of copper peroxide/COF-NH_(2)nanocomposite(CuO_(2)@COF-NH_(2)).For the colorimetric detection,NoV can be directly detected by the naked eye based on CuO_(2)@COF-NH_(2)as a laccase-like nonazyme using“peptide-NoV-antibody”recognition mode.The colorimetric assay displayed a wide and quality linear detection range from 1 copy/mL to 5000 copies/mL of NoV with a low limit of detection(LOD)of 0.125 copy/mL.For the electrochemical detection of NoV,CuO_(2)@COF-NH_(2)showed an oxidation peak of copper ion from Cu^(+)to Cu^(2+)using“peptide-NoV-antibody”recognition mode.The electrochemical assay showed a linear detection range was 1-5000 copies/mL with a LOD of 0.152 copy/mL.It's worthy to note that this assay does not need other electrical signal molecule,which provide the stable and sensitive electrochemial detection for NoV.The electrochemical and colorimetric dual-mode detection was used to detect NoV in foods and faceal samples,which has the potential for improving food safety and diagnosing of NoV-infected diarrhea.
基金supported by an Australian Research Council(ARC)Discovery Project(DP210103266)This research was supported by an AINSE Ltd.Postgraduate Research Award(PGRA).
文摘An environmentally benign,sustainable,and cost-effective supply of H_(2)O_(2)as a rapidly expanding consumption raw material is highly desired for chemical industries,medical treatment,and household disinfection.The electrocatalytic production route via electrochemical oxygen reduction reaction(ORR)offers a sustainable avenue for the onsite production of H_(2)O_(2)from O2 and H2O.The most crucial and innovative part of such technology lies in the availability of suitable electrocatalysts that promote two-electron(2e^(–))ORR.In recent years,tremendous progress has been achieved in designing efficient,robust,and cost-effective catalyst materials,including noble metals and their alloys,metalfree carbon-based materials,single-atom catalysts,and molecular catalysts.Meanwhile,innovative cell designs have significantly advanced electrochemical applications at the industrial level.This review summarizes fundamental basics and recent advances in H_(2)O_(2)production via 2e^(–)-ORR,including catalyst design,mechanistic explorations,theoretical computations,experimental evaluations,and electrochemical cell designs.Perspectives on addressing remaining challenges are also presented with an emphasis on the large-scale synthesis of H_(2)O_(2)via the electrochemical route.
基金support from the Natural Science Foundation of Shandong Province(No.ZR2021 MB075)National Natural Science Foundation of China(No.51602297)the Opening Fund of State Key Laboratory of High-Efficiency Utilization of Coal and Green Chemical Engineering(No.2021-K53).
文摘The mercury species in the ocean(MeHg,Hg^(2+))will be enriched in marine organisms and threaten human health through the food chain.While the excessive H_(2)O_(2)in the metabolic process will produce hydroxyl radicals and accelerate the aging of human cells,causing a series of diseases.Hence,the cost-effective and rapid detection of mercury and H_(2)O_(2)is of urgent requirement and significance.Here,we synthesized emerging graphitic carbon nitride quantum dots(g-CNQDs)with high fluorescence quantum yield(FLQY)of 42.69%via a bottom-up strategy by a facile one-step hydrothermal method.The g-CNQDs can detect the H_(2)O_(2)and Hg^(2+)through the fluorescence quenching effect between g-CNQDs and detected substances.With the presence of KI,g-CNQDs show concentration-dependent fluorescence toward H_(2)O_(2),with a wide detection range of 1–1000μmolL^(-1)and a low detection limit of 0.23μmolL^(-1).The g-CNQDs also show sensitivity toward Hg^(2+)with a detection range of 0–0.1μmolL^(-1)and a detection limit of 0.038μmolL^(-1).This dual-function detection of g-CNQDs has better practical application capability compared to other quantum dot detection.This study may provide a new strategy for g-CNQDs preparation and construct a fluorescence probe that can be used in various systems involving H_(2)O_(2)and Hg^(2+),providing better support for future bifunctional or multifunction studies.
基金Sumitomo Metal Mining Co.,Ltd.,Japan International Cooperation Agency(JICA),and a Grant-inAid for Science Research(JSPS KAKENHI)from the Japan Society for the Promotion of Science(JSPS)(Nos.JP22K14636,JP22H00310 and JP19H02659)This work was partly supported by Advanced Research Infrastructure for Materials and Nanotechnology(No.JPMXP1222KU1009)in Japan sponsored by the Ministry of Education,Culture,Sports,Science and Technology(MEXT),Japan.
文摘Enargite is typically associated with chalcocite.Owing to the similarity in the flotation behaviors of these minerals,both minerals are reported to concentrate in the conventional flotation circuit.However,inorganic arsenic in enargite can decrease the copper concentrate quality and increase the operating cost of processing this concentrate.Separating these minerals is important for cleaner copper production to avoid these effects.In this context,this study investigated the effect of hydrogen peroxide(H_(2)O_(2))treatment on the flotation behavior of chalcocite and enargite.Flotation tests of pure and mixed minerals indicated that H_(2)O_(2)treatment reduced the floatability of chalcocite and enargite by forming sulfate and copper hydroxide on their surfaces.Despite the detrimental effect of the H_(2)O_(2)treatment,there was a narrow window of H_(2)O_(2)concentration for separating both minerals,in which enargite floated and chalcocite was depressed.This selective flotation behavior was caused by the rapid adsorption of potassium amyl xanthate(KAX)and lower surface oxidation of enargite compared with that of chalcocite.
基金supported by the National Key Research and Development Program of China (2018YFC1901804 and 2018YFC1901805)the National Natural Science Foundation of China (21978045 and U1902219)。
文摘Copper was extracted from methylchlorosilane slurry residue by a direct hydrogen peroxide leaching method.A number of experimental parameters were analyzed to determine the extraction efficiency of copper.The extraction efficiency of copper reached 98.5%under the optimal leaching conditions,such as the hydrogen peroxide concentration of 1.875 mol·L^(-1),the leaching temperature of 323 K,the liquid–solid ratio of 20 ml·g^(-1),and the stirring speed of 300 r·min^(-1).The leaching kinetics of the copper extraction process was then described by the shrinking core model.There were two stages.The first stage was controlled by chemical reactions,while the second stage was controlled by interface transfer and product layer diffusion.The activation energy and kinetic control equations were determined,as well as an explanation of the leaching mechanism of copper extraction based on kinetic analysis and materials characterization.Copper resources can be recovered from the methylchlorosilane slurry residue efficiently and inexpensively with the methods used in this study.
基金supported by the National MCF Energy R&D Program of China (2018YFE0306105)the National Key R&D Program of China (2020YFA0406104, 2020YFA0406101)+8 种基金the Innovative Research Group Project of the National Natural Science Foundation of China (51821002)the National Natural Science Foundation of China (52201269, 52302296, 51972216)the Natural Science Foundation of Jiangsu Province (BK20220028, BK20210735)the Natural Science Foundation of the Higher Education Institutions of Jiangsu Province (21KJB430043)the Collaborative Innovation Center of Suzhou Nano Science & Technology, the 111 Projectthe Suzhou Key Laboratory of Functional Nano & Soft Materials, the Jiangsu Key Laboratory for Advanced Negative Carbon Technologiesthe Science and Technology Development Fund, Macao SAR (0009/2022/ITP)the funding from Gusu leading talent plan for scientific and technological innovation and entrepreneurship (ZXL2022487)China Scholarship Council (CSC) for the Ph.D. fellowship。
文摘It is of great interest to develop the novel transition metal-based electrocatalysts with high selectivity and activity for two electron oxygen reduction reaction(2e^(-) ORR).Herein,the nickel ditelluride(NiTe_(2)) with layered structure was explored as the 2e^(-) ORR electrocatalyst,which not only showed the highest 2e^(-) selectivity more than 97%,but also delivered a slight activity decay after 5000 cycles in alkaline media.Moreover,when NiTe_(2) was assembled as the electrocatalyst in H-type electrolyzer,the on-site yield of H_(2)O_(2) could reach up to 672 mmol h^(-1)g^(-1) under 0.45 V vs.RHE.Further in situ Raman spectra,theoretical calculation and post microstructural analysis synergistically unveiled that such a good 2e^(-) ORR performance could be credited to the intrinsic layered crystal structure,the high compositional stability,as well as the electron modulation on the active site Ni atoms by neighboring Te atoms,leading to the exposure of active sites as well as the optimized adsorption free energy of Ni to –OOH.More inspiringly,such telluride electrocatalyst has also been demonstrated to exhibit high activity and selectivity towards 2e^(-) ORR in neutral media.
基金the financial support(Research Council Grant)provided by Isfahan University of Technology(Iran).
文摘A series of CoPd/KIT-6 bimetallic catalysts with various Co:Pd molar ratios at different calcination temperatures were prepared and used for the direct synthesis of H_(2)O_(2) from H_(2) and O_(2).These catalysts were characterized by nitrogen adsorption-desorption,low and wide-angle X-ray diffraction(XRD),X-ray photoelectron spectroscopy(XPS),transmission electron microscopy(TEM),scanning electron microscopy(SEM),elemental mapping and energy-dispersive X-ray(EDX)methods.It was found that the particle size,electronic interactions,morphology,and textural properties of these catalysts as well as their catalytic activity in the reaction of H_(2) with O_(2) were affected by Co addition and different calcination temperatures.Also,the results showed that while the H_(2)O_(2) selectivity depends on Pd^(2+) species,the H_(2) conversion is related to Pd0 active sites.Among these catalysts,CoPd/KIT-6 calcined at 350℃(CoPd/KIT-350 catalyst)showed the best catalytic activity with 50%of H_(2)O_(2) selectivity and 51%conversion of H_(2).
基金This work was financially supported by the Gansu Provincial Natural Science Foundation of China(Nos.21JR7RA493,17JR5RA198,2020HZ‐2,21JR7RA470)the Cooperation project of Gansu Academy of Sciences(2020HZ‐2)+6 种基金the Fundamental Research Funds for the Central Universities(Nos.lzujbky‐2018‐119,lzujbky‐2018‐ct08,lzujbky‐2019‐it23)Key Areas Scientific and Technological Research Projects in Xinjiang Production and Construction Corps(No.2018AB004)Hubei University of Arts and Science(No.2020kypytd002)Xiangyang Science and Technology Research and Development(No.2020YL09)the Science and Technology Research Project of Hubei Provincial Department of Education(No.D20212603)All the DFT calculations were supported by the Supercomputing Center of Lanzhou UniversityAll SEM,TEM,and HAADFSTEM were supported by the Electron Microscopy Centre of Lanzhou University.
文摘Platinum-based materials show excellent electrocatalytic performance and have good potential for use in fuel cells.However,the high cost and scarce reserves have restricted their wide application.Therefore,it is a challenging task to reduce the amount of Pt as well as ensure good catalytic performance.Herein,anchoring of Pt single atoms(0.21 wt‰)with ultra-low content on g-C_(3)N_(4)nanosheets(Pt_(0.21)/CN)has been successfully achieved.The obtained Pt_(0.21)/CN catalyst shows excellent two-electron oxygen reduction(2e-ORR)capability for hydrogen peroxide(H_(2)O_(2)).Compared with CN,its H_(2)O_(2)selectivity increased from 80%to 98%in 0.1M KOH,surpassing those in most of the reported studies.Besides,the H_(2)O_(2)production rate of Pt_(0.21)/CN is 767 mmol gcat^(-1)h-1,which is 11.1 times that of CN.This work may pave the way toward the development of an effective method for the design of noblemetal electrocatalysts with low metal loading and high catalytic activity.
文摘Seborrheic keratosis has a varying degree of pigmentation. In pigmented seborrheic keratosis, the proliferating keratinocytes trigger the activation of neighboring melanocytes by secreting melanocyte-stimulating cytokines. The etiology of seborrheic keratosis is not known. Epidermal growth factors or their receptors have been implicated in the development of seborrheic keratosis. Seborrheic keratoses can safely be left alone, but ugly or easily traumatized ones can be removed with cryotherapy, electrodesiccation, curettage, or shave excision. The present work aims to compare two modalities of treatment for seborrheic keratosis, namely cryotherapy and hydrogen peroxide (30%). Methods: 30 patients with seborrheic keratosis were included in this study. They were divided into two groups, each with 15 patients. The treatment modalities that have been used include cryotherapy and hydrogen peroxide in three different concentrations (30%, 35%, and 40%). Result: The cryotherapy group consisted of 15 patients, 7 males and 8 females. Their ages ranged from 38 to 80 years, with a mean of 56.1 ± 11.4. Clinical and photographic assessments showed complete removal in all 15 patients in this group (100%). As regards the hydrogen peroxide group, this group included 15 patients, distributed among 7 males and 8 females. Their ages ranged from 39 to 90 years, with a mean of 53.9 ± 14.4. Clinical and photographic assessments showed response in only one small superficial lesion in one patient (6.7%) and no response in 14 patients (93.3%). Conclusion: Cryotherapy is an effective, easy, and relatively cheap method for treating seborrheic keratosis.
基金supported by the National Research Foundation of Korea(NRF)grant funded by the Korea government(MSIT)(Nos.2017R1D1A1B03032033 and 2020R1C1C1010386)“Leaders in INdustry-university Cooperation+”project supported by the Ministry of Education and National Research Foundation of Korea。
文摘In this study,an amine-coordinated cobalt phthalocyanine(CoPc)-based anodic catalyst was fabricated by a facile process,to enhance the performance of hydrogen peroxide fuel cells(HPFCs) and enzymatic biofuel cells(EBCs).For this purpose,polyethyleneimine(PEI) was added onto the reduced graphene oxide and CoPc composite(RGO/CoPc) to create abundant NH2 axial ligand groups,for anchoring the Co core within the CoPc.Owing to the PEI addition,the onset potential of the hydrogen peroxide oxidation reaction was shifted by 0.13 V in the negative direction(0.02 V) and the current density was improved by 1.92 times(1.297 mA cm^(-2)),compared to those for RGO/CoPc(0.15 V and 0.676 mA cm^(-2),respectively),due to the formation of donor-acceptor dyads and the prevention of CoPc from leaching out.The biocatalyst using glucose oxidase(GOx)([RGO/CoPc]/PEI/GOx) showed a better onset potential and catalytic activity(0.15 V and 318.7 μA cm^(-2)) than comparable structures,as well as significantly improved operational durability and long-term stability.This is also attributed to PEI,which created a favorable microenvironment for the enzyme.The maximum power densities(MPDs) and open-circuit voltages(OCVs) obtained for HPFCs and EBCs using the suggested catalyst were 105.2±1.3 μW cm^(-2)(0.317±0.003 V) and 25.4±0.9 μW cm^(-2)(0.283±0.007 V),respectively.This shows that the amine axial ligand effectively improves the performance of the actual driving HPFCs and EBCs.
文摘In the present paper, blood lipids peroxide(LPO) level and activities of glutathione peroxidase(GSH-Px) and superoxide dismutase(SOD) were investigated before and after combined treatment of acupuncture and moxibustion and Chinese drugs in patients of vascular dementia(VD), and their results were compared with those in healthy persons with the similar ages to the patients. The results showed that the blood LPO level increased significantly, and the activities of SOD and GSH-Px reduced significantly in patients of VD as compared with those in the control group. Degrees of patient’s condition were related with amplitudes of the increase of LPO and the reduction of activities of GSHPx and SOD. Combined treatment of acupuncture and moxibustion and Chinese drugs could raise markedly activitles of blood GSH-Px and SOD, and lowered LPO level in the patients of VD, which are related to clinical therapeutic effects. It is considered that combination of acupuncture and moxibustion with Chinese drugs can increase the action of the antiperoxidative system in the patients of VD, exerting anti-peroxidative ability and clearing LPO and reducing the oxidative injury of the organism by oxygen free radical, which is one of mechanisms of combined treatment of acupuncture and moxibustion with Chinese drugs.
文摘The level of lipid peroxides (LPO) and copper-zinc containing superoxide dismutase (SOD-Ⅰ) in the gastric mucosa and serum was determined in 141 samples from 25 patients after con-ventional subtotal gastrectomy (11 cases of Billroth Ⅰ and 14 cases of Billroth Ⅱ) and 11 patientsafter pylorus and antroseromuscular flap preserving gastrectomy (PAFPG).Those of 11 normal subjects were examined likewise to serve as control.It was found that:(1) The average LPO levelwas much higher and the average SOD-Ⅰ level much lower in the gastric mucosa of the patientsafter conventional subtotal gastrectomy especially the Billroth Ⅱ type than in that of those afterPAFPG.(2) In 36 specimens of stump mucosa,the average LPO level was significantly higher inthe tissue around the anastomotic ring than in that of the body of the stump;no marked differ-ence of SOD-Ⅰ level between the 2 was revealed.(3) The LPO value in the stump mucosa waspositively correlated to and the SOD-Ⅰ value negatively correlated to the pH value of gastric juice.These rindings suggest that the reation of oxygen free radicals in the stump mucosa may be influ-enced by the intragastric pH or by the type of digestive continuity reconstruction,and that thereaction of oxygen free radicals especially the lipid peroxidation may play a role in the pathogenesisof the lesions in the anastomotic stoma.
基金Supported by All India Council for Technical Education
文摘Objective:To evaluate the anti-apoptotic and radical scavenging activities of dietary phenolics, namely ascorbic acid,a-tocopherol acetate,citric acid,salicylic acid,and estimate H_2O_2induced apoptosis in renal cell carcinoma cells.Methods:The intracellular antioxidant potency of antioxidants was investigated.H_2O-2-induced apoptosis in RCC-26 was assayed with the following parameters:cell viability(%apoptosis),nucleosomal damage and DNA fragmentation, bcl-2 levels and flow cytometery analysis(ROS production evaluation).Results:Ine anticancer properties of antioxidants such as ascorbic acid,a- tocopherol acetate,citric acid,salicylic acid with perdurable responses were investigated.It was observed that these antioxidants had protective effect(anti-apoptotic activity) against hydrogen peroxide(H_2O_2) in renal cell carcinoma(RCC-26) cell line.Conclusions:This study reveals and proves the anticancer properties.However,in cancer cell lines anti-apoptotic activity can indirectly reflect the cancer promoter activity through radicals scavenging,and significantly protect nucleus and bcl-2.
文摘Objective:To investigate thein vitroantioxidant potential of Carica papaya(C. papaya) leaf extract and its effect on hydrogen peroxide-induced erythrocyte damage assessed by haemolysis and lipid peroxidation.Methods:Hydroxyl radical scavenging activities, hydrogen ion scavenging activity, metal chelating activity, and the ferrous ion reducing ability were assessed as antioxidant indices. In the other experiment, human erythrocytes were treated with hydrogen peroxide to induce erythrocyte damage. The extract(at various concentrations) was subsequently incubated with the erythrocytes and later analysed for haemolysis and lipid peroxidation as indices for erythrocyte damage.Results:Preliminary investigation of the extract showed that the leaf possessed significant antioxidant and free radical scavenging abilities usingin vitro models in a concentration dependent manner(P<0.05). The extract also reduced hydrogen peroxide induced erythrocyte haemolysis and lipid peroxidation significantly when compared with ascorbic acid(P<0.05). The IC50values were 7.33 mg/mL and 1.58 mg/mL for inhibition of haemolysis and lipid peroxidation, respectively. In all cases, ascorbic acid(the reference antioxidant) possessed higher activity than the extract.Conclusions:The findings show that C. papayaleaves possess significant bioactive potential which is attributed to the phytochemicals which act in synergy.Thus, the leaves can be exploited for pharmaceutical and nutritional purposes.
基金financially supported by the National Natural Science Foundation of China,No.81574038(to ZZW)the Natural Science Foundation of Guangdong Province of China,No.2017A030313842(to LHD)+1 种基金the Science and Technology Foundation of Guangdong Province of China,No.2017A050506007(to YHL)the Technology Research Foundation of Basic Research Project of Shenzhen City of China,No.JCYJ20170412161254416(to ZZW)
文摘Alpinia oxyphylla,a traditional herb,is widely used for its neuroprotective,antioxidant and memory-improving effects.However,the neuroprotective mechanisms of action of its active ingredients are unclear.In this study,we investigated the neuroprotective effects of various organic extracts of Alpinia oxyphylla on PC12 cells exposed to hydrogen peroxide-induced oxidative injury in vitro.Alpinia oxyphylla was extracted three times with 95%ethanol(representing extracts 1–3).The third 95%ethanol extract was dried and resuspended in water,and then extracted successively with petroleum ether,ethyl acetate and n-butanol(representing extracts 4–6).The cell counting kit-8 assay and microscopy were used to evaluate cell viability and observe the morphology of PC12 cells.The protective effect of the three ethanol extracts(at tested concentrations of 50,100 and 200μg/mL)against cytotoxicity to PC12 cells increased in a concentration-dependent manner.The ethyl acetate,petroleum ether and n-butanol extracts(each tested at 100,150 and 200μg/mL)had neuroprotective effects as well.The optimum effective concentration ranged from 50–200μg/mL,and the protective effect of the ethyl acetate extract was comparatively robust.These results demonstrate that organic extracts of Alpinia oxyphylla protect PC12 cells against apoptosis induced by hydrogen peroxide.Our findings should help identify the bioactive neuroprotective components in Alpinia oxyphylla.
基金supported by Tianjin Science and Technology Project(No.19YFSLQY00070)Foundation for State Key Laboratory of Organic–Inorganic Composites,Beijing University of Chemical Technology(No.oic-201901004)Hundred Talent Program of the Chinese Academy of Sciences。
文摘Electrochemical synthesis of hydrogen peroxide(H2 O2)provides a clean and safe technology for large-scale H2 O2 production.The core of this project is the development of highly active and highly selective catalysts.Recent studies demonstrate that carbonaceous materials are favorable catalysts because of their low-cost and tunable surface structures.This brief review first summarizes the strategies of carbonaceous material engineering for selective two-electron O2 reduction reaction and discusses potential mechanisms.In addition,several device designs using carbonaceous materials as catalysts for H2 O2 production are introduced.Finally,research directions are proposed for practical application and performance improvement.
基金Australian Postgraduate Award(APA)Ph.D. fellowship by Western Sydney University to DG
文摘Nitric oxide is now universally recognized as an extracellular signaling molecule. Nitric oxide, produced in one cell, diffuses across the extracellular space and acts with targets in an adjoining cell. In this study, we present proof that hydrogen peroxide - like nitric oxide - acts as a true first (intercellular) messenger for a multitude of pro-inflammatory ligands. RAW 264.7 macrophages were activated with three different ligands, lipopolysaccharide, interferon-gamma or advanced glycation end products in the presence of increasing concentrations of (hydrogen peroxide scavenging) catalase. As inflammatory readouts, nitric oxide and tumor necrosis factor were determined. We hypothesize that hydrogen peroxide travels between cells propagating the signal, then a certain percentage of the readout should be inhibited by catalase in a concentration- dependent manner. The experiment showed concentration-dependent inhib让ion of nitric oxide and tumor necrosis factor-a production in response to all three ligands/ligand combinations (interferon-gamma, lipopolysaccharide, and chicken egg albumin-derived advanced glycation end product) in the presence of increasing concentration of catalase. For example, catalase inhibited 100% of nitric oxide and 40% of tumor necrosis factor-a production at its highest concentration. Our results suggest that hydrogen peroxide travels through cell membranes into the extracellular space and enters and activates ad;acent cells. Like rdtric oxide, we suggest that it is a ubiquitous first messenger, able to transmit cell-to-cell pro-inflammatory signals such as nitric oxide and tumor necrosis factor-a. In a therapeutic setting, our data suggest that compounds acting as hydrogen peroxide scavengers might not even need to enter the cell to act as anti-inflammatory drugs.
