Antitumor Activity of the Ganoderma Lucidum Spore Alcohol Extract in Vitro

Several cancer cell lines(epithelioma cells or leukemia cells)from human being or mouse were first used to study the antitumor activity of the Ganoderma lucidum spore alcohol extract(GLSAE)in vitro by the MTT test A comparision was made between the sporodermbroken(SB)and sporoderm nonbroken(SN)GLSAE It was showed that both GLSAE SB and GLSAE SN could inhibit the proliferation of these cancer cells,but the activity of GLSAE SB was much higher than that of GLSAE SN These results suggested that Ganoderma lucidum spore could probably be used for tumor treatment

阳图热敏CTP版涂层中树脂种类对润版液的影响

目前,阳图热敏CTP版材在印刷行业中已经广泛使用,为了指导其在印刷过程中的正确使用,提高耐印力,本文研究了专利中介绍的阳图热敏CTP版材的感光涂层组分中不同种类的成膜树脂和添加树脂在异丙醇中的溶解速率和溶解度差异,主要研究了以上不同种类的树脂按照一定配方制成版材后的抗醇性、耐磨性模拟耐印力检测实验的方法和抗醇性、耐磨性和模拟耐印力实验检测的性能差异。实验结果表明:不同种类的成膜树脂和添加树脂在异丙醇中的溶解速率和溶解度不同,制成版材后版材的抗醇性也不同,溶解速率和溶解度大的树脂制成的版材抗醇性差,但是耐磨性和醇中的溶解性并无直接关系。通过对以上结果分析,影响阳图热敏CTP版材耐印的因素中抗醇性和耐磨性是两个重要的方面,其中耐醇性占主要作用。不同种类的阳图热敏CTP版材在印刷过程中对使用的润版液的异丙醇耐受力不同,根据溶解度参数理论,指导研发过程中树脂种类的筛选和优化,同时指导正确使用润版液,尤其控制好醇类使用量可以克服版材在印刷过程中掉版和耐印力低的问题。指出了阳图热敏CTP版材在印刷过程中向着使用无醇润版液的趋势发展,于此同时阳图热敏CTP版材的研制向着提高抗醇性的方向发展,为印刷业的发展提供更宽广的选择性。

Gold nanoparticle stabilization within tailored cubic mesoporous silica:Optimizing alcohol oxidation activity

Stabilizing gold nanoparticles（AuNPs） within a desired size range is critical to realize their promising catalytic performance in many important reactions.Herein,we investigate the anti-sintering properties of cubic mesoporous silica（FDU-12） as a function of pore entrance size.Simple adjustments to the type of organic template and reaction temperature enable the successful synthesis of FDU-12 with controllable entrance sizes（ 3,3-5 and 7 nm）.Excellent anti-sintering properties are observed for FDU-12 with a sub-5-nm entrance size（3-5 nm） over a wide loading concentration（1.0-8.3 wt%） and the AuNPs can be stabilized within a 4.5-5.0-nm range after calcination at 550 ℃in air for 5 h.Smaller entrance size（ 3 nm） prevents ingress of 3-nm AuNPs to the mesopores and results in low loading capacity and sintering.Conversely,FDU-12 possessing a larger entrance size（7 nm） shows promising anti-sintering properties at high loading concentrations,although catalytic performance is significantly lost at lower concentrations（e.g.2.1 wt%,14.2 ± 5.5 nm）.Different anti-sintering mechanisms are proposed for each of the different FDU-12 entrance sizes.Additionally,catalytic data indicates that the obtained 4.5-nm AuNPs supported on FDU-12 with a sub-5-nm entrance size exhibit excellent mass-specific activity（1544 mmol g_（Au）^（-1） h^（-1）） and selectivity（ 99%）at 230 ℃ for the gas-phase selective oxidation of cyclohexanol.

Severe ulcerative colitis: At what point should we define resistance to steroids?

Corticoesteroids are still the first-line treatment for active ulcerative colitis more than 50 years after the publication of trials assessing their beneficial effect, with about a 50% remission rate in cases of severe disease. The mortality related to severe attacks of ulcerative colitis has decreased dramatically, to less than 1%, in experienced centers, due to the appropriate use of intensive therapeutic measures (intravenous steroids, fluids and electrolytes, artificial nutritional support, antibiotics, etc), along with timely decision-making about second-line medical therapy and early identification of patients requiring colectomy. One of the most difficult decisions in the management of severe ulcerative colitis is knowing for how long corticosteroids should be administered before deciding that a patient is a non-responder. Studies assessing the outcome of acute attacks after steroid initiation have demonstrated that, in steroid-sensitive patients, the response generally occurs early on, in the first days of treatment. Different indexes to predict treatment failure, when applied on the third day of treatment, have demonstrated a high positive predictive value for colectomy. In contrast to this resolute approach, which is the most widely accepted, other authors have suggested that in some patients a completeand prolonged response to steroids may take longer. Either way, physicians taking care of these patients need to recognize that severe ulcerative colitis may be life-threatening, and they need to be careful with excessively prolonged medical treatment and delayed surgery.

Eradication of Helicobacter pylori significantly reduced gastric damage in nonsteroidal anti-inflammatory drug-treated Mongolian gerbils

AIM: To examine the effect of eradication of Hellcobacter pylori prior to usage of NSAIDs, by investigating gastric inflammatory activity, myeloperoxidase (MPO) activity, prostaglandin (PG) E_2 synthesis in H Pylori-infected, and H pylori-eradicated gerbils followed by administration of indomethacin and rofecoxib. METHODS: Six-week-old male gerbils were orally inoculated with H pylori. Seven weeks later, anti-H pylori triple therapy and vehicle were given to gerbils respectively and followed by oral indomethacin (2 mg/kg·d) or rofecoxib (10 mg/kg·d) for 2 wk. We examined the area of lesions, gastric inflammatory activity, PGE_2 synthesis and MPO activity in the stomach. RESULTS: In indomethacin and rofecoxib-treated gerbils, the following results were obtained in H pylori-infected group vs H pylori-eradicated group respectively: hyperplasia area of the stomach (mm^2): 82.4±9.2 vs 13.9±3.5 (P＜0.05), 30.5±5.1 vs 1.3±0.6 (P＜0.05); erosion and ulcer area (mm^2): 14.4±4.9 vs 0.86±0.5 (P＜0.05), 1.3±0.6 vs0.4±0.3 (P＜0.05); score of gastritis: 7.0±0.0 vs3.6±0.5 (P＜0.05), 7.0±0.0 vs 2.7±0.5 (P＜0.05); MPO activity (μmol H_2O_2/min/g tissue): 104.7±9.2 vs9.0±2.3(P＜0.05), 133.5±15.0 vs2.9±0.7 (P＜0.05); PGE_2 synthesis (pg/mg wet weight/min): 299.2±81.5 vs102.8±26.2 (P＜0.05), 321.4±30.3 vs 11.9±4.8(P＜0.05). CONCLUSION: Eradication of H pylori reduced gastric damage of NSAID-treated Mongolian gerbils. Rofecoxib caused less severe gastric damage than indomethacin in H pylori-eradicated gerbils.

Determination of the Content of Total Alkaloids in Different Solvent Extracts from Climbing Groundsel Herb Produced in Guizhou Province and Their Antibacterial Activity

[Objective] This study aimed to compare the contents of total alkaloids in different solvent extracts from climbing groundsel herb produced in Guizhou Province and their antibacterial activity. [Method] The content of total alkaloids was measured by UV spectrophotometry, and Oxford cups were used to investigate the antibacterial activity of each solvent extract. [Result] There was a good linear correlation between the absorbance measured by the UV spectrophotometer and the content of total al- kaloids within the concentration of 0.011 0-0.054 8 mg/ml at 207 nm, and the re- gression equation was Y=23.654X＋0.021, R=0. 999 7 and the average recovery rate was 99.2%. The contents of total alkaloids in 60% ethanol extract, 95% ethanol and water ethanol were 38.71, 52.25 and 60.50 mg/g, respectively. The 60% ethanol ex- tract had strong antibacterial activity against Streptococcus pneumoniae, Staphylo- coccus aureus and Escherichia coil; the water extractive had stronger antibacterial activity against Escherichia colr, 95% ethanol extract had weak antibacterial activity, with no inhibition of Pseudomonas aeruginosa. [Conclusion] This method is accurate, simple, with good repeatability, which can be used for the determination of alkaloids content of the climbing groundsel herb; there is no positive correlation between the content of total alkaloids in different solvent extracts of climbing groundsel herb and their antibacterial activity.

Anticancer activity of resveratrol on implanted human primary gastric carcinoma cells in nude mice

AIM: To investigate the apoptosis of implanted primary gastric cancer cells in nude mice induced by resveratrol and the relation between this apoptosis and expression of bcl-2 and bax. METHODS: A transplanted tumor model was established by injecting human primary gastric cancer cells into subcutaneous tissue of nude mice. Resveratrol (500 mg/kg, 1 000 mg/kg and 1 500 mg/kg) was directly injected beside tumor body 6 times at an interval of 2 d. Then changes of tumor volume were measured continuously and tumor inhibition rate of each group was calculated. We observed the morphologic alterations by electron microscope, measured the apoptotic rate by TUNEL staining method, detected the expression of apoptosis-regulated genes bcl-2 and baxby immunohistoch-emical staining and PT-PCR. RESULTS: Resveratrol could significantly inhibit carcinoma growth when it was injected near the carcinoma. An inhibitory effect was observed in all therapeutic groups and the inhibition rate of resveratrol at the dose of 500 mg/kg, 1 000 mg/kg and 1 500 mg/kg was 10.58%, 29.68% and 39.14%, respectively. Resveratrol induced implanted tumor cells to undergo apoptosis with apoptotic characteristics, including morphological changes of chromatin condensation, chromatin crescent formation, nucleus fragmentation. The inhibition rate of 0.2 mL of normal saline solution, 1 500 mg/kg DMSO, 500 mg/kg resveratrol, 1 000 mg/kg resveratrol, and 1 500 mg/kg resveratrol was 13.68±0.37%, 13.8±0.43%, 48.7±1.07%, 56.44±1.39% and 67±0.96%, respectively. The positive rate of bd-2 protein of each group was 29.48±0.51%, 27.56±1.40%, 11.86±0.97%, 5.7±0.84% and 3.92±0.85%, respectively by immunohistochemical staining. The positive rate of bax protein of each group was 19.34±0.35%, 20.88±0.91%, 40.02±1.20%, 45.72±0.88% and 52.3±1.54%, respectively by immunohistochemical staining. The density of bcl-2 mRNA in 0.2 mL normal saline solution, 1 500 mg/kg DMSO, 500 mg/kg resveratrol, 1 000 mg/kg resveratrol, and 1 500 mg/kg resveratrol decreased progressively and the density of bax mRNA in 0.2 mL normal saline solution, 1 500 mg/kg DMSO, 500 mg/kg resveratrol, 1 000 mg/kg resveratrol, and 1 500 mg/kg increased progressively with elongation of time by RT-PCR. CONCLUSION: Resveratrol is able to induce apoptosis of transplanted tumor cells. This apoptosis may be mediated by down-regulating apoptosis-regulated gene bcl-2 and up-regulating the expression of apoptosis-regulated gene bax.

Synthesis and Antifungal Activity of 1-(1H-1,2,4-Triazole)-2-(2,4-diflurophenyl)-3-(N-methyl-N-substituted benzylamino)-2-propanols

Eleven 1-(1H-1,2,4-triazole)-2-(2,4-diflurophenyl)-3-(N-methyl-N-substituted benzylamino)-2-propanols were designed and synthesized, on the basis of the crystal structure of P450 cytochrome 14α-sterol demethylase(CYP51) and the docking results of inhibitors to the active site of the enzyme. All title compounds were first by reported. Results of preliminary biological tests showed that most of title compounds exhibited activity against the seven common pathogenic fungi. Compound 11 showed best antifungal activity with broad antifungal spectrum and proved to be more active against Cryptococcus neoformans, Candida albicans, Microsporum lanosum and Trichophyton rubrum than ketoconazole. Compounds 3, 10 and 4 also had high activities.

Relationships between Different Preparations of Cotton Hollow Yarn and Water Soluble PVA Extraction

In this paper cotton hollow yarns were obtained from the core spun yams which were produced on a little modified conventional experiment ring frame with water soluble staple PVA yam as the core. For comparison, yams with same linear densities, same twists of the sheath, different linear densities, different twist directions of the core were prepared. The results show that the tensile strengths of the hollow yarns decrease first, then increase and decrease again, at last the tensile strength trends to reach a steady state with the soluble PVA core extraction proceeding. And when the sheath linear densities of the core spun yams are constant, their twist and twist direction are same as that of the core it will be easier to remove the core of the yam with a higher core size. When the linear densities of the sheath and the core are all constant, the twists of them are same, it will be easier to remove the core of the yam with a different twist direction of core to the sheath.

Relationship between Ethanol and 2-phenylethanol Stress Tolerance and Fatty Acid Compositions of Saccharomyces cerevisiae

In the present study, we investigated of the ethanol （Eth）, 2-phenylethanol （2-PE） and ethanol/2-phenylethanol （Eth/2-PE） stress tolerance and established relationship between stress tolerance and fatty acid compositions of wine yeast strain S. cerevisiae UCM Y-524 in relation to different cultivation factors. Changes in cell membrane fatty acid profiles studied under different temperature and media. The active oxygenation, semi-aerobic cultivation supplemented Tween 80 conditions were used in different combinations. The concentrations of 2-PE and Eth, the fatty acids methyl esters （FAMES） in the media were measured by GC-MS analyses. 2-PE, Eth, FAMES were identified by NIST02 MS database at the 2-PE and Eth standard solution （Merck, Germany）, bacterial FAMES standard （Supelco）. Palmitoleic and oleic acid were dominated for S. cerevisiae UCM Y-524. The unsaturated/saturated fatty acid （UFA/SFA） ratio was higher than five for S. cerevisiae UCM Y-524 at 14 ~C in simple medium and about more than three for other conditions. It has been found that yeast cells grown in the presence of the 2-PE, Eth and Eth/2-PE appear to increase the amount of unsaturated fatty acids, especially oleic acid, in cellular lipids especially under active oxygenation supplemented with Tween 80. S. cerevisiae UCM Y-524 has a higher tolerance under 2-PE, Eth and Eth/2-PE stress at 28 ~C in a simple medium under aerobic conditions. A higher concentration of unsaturated fatty acids in the membrane S. cerevisiae UCM Y-524 and a lower temperature under aerobic conditions, has been considered to have a positive influence on the excretion of 2-phenylethanol.

Comparison of Antioxidant and Antimicrobial Activities of Methanolic Extracts of the Artemisia sp.Recovered by Different Extraction Techniques

The polyphenol content,antioxidant and antimicrobial activities of the extracts obtained by classical, ultrasonic and Soxhlet extractions from dry aerial parts of two Artemisia species(Artemisia vulgaris and Artemisia campestris)were compared.Ultrasound positively affected the yield of extractive substance and the kinetics of extraction,but the extract obtained by the classical extraction showed the highest antioxidant activities and contained higher total contents of phenolic compounds and flavonoids than the extracts obtained by two other extraction techniques.Both flavonoid aglycones(apigenin,quercetin,quercetin 3,3′-dimethyl ether)and flavonoid glycosides(rutin,hyperoside and kaempferol 3-rhamnoside)were identified by thin layer chromatograph(TLC)analysis in the extracts from both species.A.campestris extracts were richer in quercetin than A.vulgaris and its antimicrobial activity was also better than A.vulgaris.Extracts obtained from both species were found to be more effective on the tested yeasts than bacteria.The kinetics of the total extractive substances,such as phenolic,flavonoids and quercetin extraction,was successfully described by the model of unsteady-state diffusion.

Antioxidant Activity of Ethanol Extract of Pomegranate Seed

In this study, the ethanol extract of pomegranate seed was prepared and its antioxidant activities were investigated. It was found the total phenolic content in the extract was as high as 41.791 mg GAE/g. And the extract showed high antioxidant activity measured as scavenging of DPPH radicals, hydroxyl radicals. It also exhibited strong antioxidant activity in reducing power and Rancimat test. These results demonstrated Pomegranate seeds could serve as a new source of natural antioxidant.

Chemical Composition, Antioxidant and Antibacterial Activities of the Essential Oil and Methanol Extract from Mentha Iongifolia L. Hudson from North of Iran

This study was designed to evaluate antimicrobial and antioxidant activities of the essential oil and methanol extract from Mentha longifolia L. hudson. Antioxidant activity was evaluated through 2,2-diphenyl-l-picrylhydrazyl （DPPH） assay and β-carotene/linoleic acid assay. The essential oil and methanol extract were individually tested [disc-diffusion assay and evaluating minimum inhibition concentration （MIC）] against a number of bacteria. The essential oil showed strong antimicrobial activity against bacteria tested whereas the methanol extract almost remained inactive. In contrast, the extract showed much better activity than the essential oil in antioxidant activity assays employed, e.g. in the inhibition of free radical DPPH and β-carotene/linolcic acid systems. In the former, the extract was able to reduce the stable free radical DPPH with an IC50 of 55.3μg/mL while that of the oils were 10,630μg/mL. When compared to BHT （butylated hydroxytoluene）, a synthetic antioxidant, both showed weaker antioxidative potential. Similarly, in β-carotene/linoleic acid assay, these samples were not effectively able to inhibit the linoleic acid oxidation; exhibiting only 24% and 36% inhibitions at 2 mg/mL, respectively; both were far below than that of BHT. Total phenolic constituent of the extract was approximately 4.5 g/100 g as gallic acid equivalent. Gas chromatography-mass spectroscopy （GC-MS） analysis of the oil resulted in the identification of 45 constituents, ei^-piperitone epoxide, pulegone and piperitenone oxide being the main components. The results indicate that essential oil and extract ofM. longifolia L. hudson may be used as natural preservative in food against the agents of foodborne diseases and food spoilage.

Inhibition of Ehrlich Ascites Carcinoma by Lactuca serriola in Swiss Albino Mice

To evaluate the antitumor activity of Lactuca serriola against EAC （Ehrlich ascites carcinoma） in Swiss albino mice. The in vivo antitumor activity of the methanol extract of plant Lactuca serriola was evaluated at （100 mg/kg and 200 mg/kg of hole plant and 200 mg/kg, 400 mg/kg of fruit bw） against EAC using mean survival time. After administration of the extracts of Lactuca serriola, viable EAC cell count and body weight in the EAC tumor hosts were observed. The animal was also observed for improvement in the hematological parameters （e.g., hemoglobin content, red and white blood cells count and differential cell count） after treatment of plant extract. Intraperitoneal administration of plant extracts reduced viable EAC cells, increased the survival time and restored altered hematological parameters. Significant efficacy was observed for fruit extract at high concentration 400 mg/kg dose （P 〈 0.05）. It can be concluded that the methyl extract ofLactuca serriola possesses significant antitumor activity.

Anti-Inflammatory Activity of Ferruginol from Prumnupitys andina

Ferruginol, a phenolic diterpenoid, was isolated from Prumnupitys andina, a Chilean native plant, as the main compound. Ferruginol has displayed an interesting range of biological activities such as in vitro anti-inflammatory activity. Aim of this research is to evaluate the dermal anti-inflammatory activity of ferruginol, using in vivo models at first time. Ferruginol was subjected to topical assays for the inhibition of inflammation elicited by AA （arachidonic acid） or TPA （phorbol ester） in the murine model. The topical anti-inflammatory activity was evaluated in vivo using groups of 8 animals were treated with a single dose of ferruginol, equimolar doses with regard to the reference drugs, indomethacin and nimesulide. We showed a chemical data were consistent with a type-abietane diterpenoid known as ferruginol. Ferruginol showed topical anti-inflammatory activity at 21.0% and 20.5% in AA and TPA models, respectively. Our results provide data to support further investigations about ferruginol, a type-abietane diterpenoid, as a potential anti-inflammatory agent.

Antioxidant Activity and Anti-Hyperglycemic Effect of Lagenaria Siceraria Fruit Extract

Lagenaria siceraria （Molina） Standl., known as bottle gourd is widely available throughout Vietnam as an edible vegetable. Bottle gourd is a commonly fruit but there are little reports about its biological activities. The aim of the present study was to evaluate antioxidant activity and anti-hyperglycemic potential of ethanolic extract of bottle gourd. The ethanolic extract was tested for its antioxidant activity on chelating power, the ferric reducing/antioxidant power assay （FRAP） and the 1, 1-diphenyl-2-picryl-hydrazyl （DPPH） free radical scavenging assay. The results showed that chelating activity was 80.02%, FRAP value was 92.84 μmol Fe^2＋/g and active radical scavenging which showed an IC50 was 49.50 μg/ml. The five different doses of ethanolic extract were treated by oral tolerance to mice body before oral glucose tolerance and blood glucose level was measured using glucose oxidase method. The result indicated that inhibition percentage of ethanolic extract of bottle gourd at the dose of 400 mg/kg in glucose-induced hyperglycemic mice was effectively similar to standard drug glibenclamide. The results obtained indicate that ethanolic extract from bottle gourd is the potential antioxidant and anti-hyperglycemic agent.

Antinociceptive and Anti-inflammatory Activities of Methanol Extract of Ormosia coccinea （Aubl,） Jacks in vivo

The present study was conducted to evaluate the antinociceptive and anti-inflammatory activities of methanol extract of rachis of Ormosia coccinea （Aubl.） Jacks （MEOC） using animal models of nociception and inflammation. The antinociceptive activity of the extract was assessed using acetic acid-induced abdominal writhing, hot-plate, and formalin tests. Oral administration of MEOC （500 mg/kg） produced significant （t7 〈 0.05） antinociceptive effects when tested in mice using acetic acid-induced abdominal writhing test and on the inflammatory phase of the formalin test. It was also demonstrated that MEOC had no significant effect on the response latency time to the heat stimulus in the thermal model of the hot plate test. The anti-inflammatory activity of the extract was assessed using carrageenan, histamine and serotonin induced oedema in rat paw. The oral administration of MEOC showed maximum inhibition （64.29%） at 1 h on carrageenan edema, but it did not modify the edema induced by histamine and serotonin. The present results suggest that MEOC has a peripheral antinoeiceptive and anti-inflammatory action.

Polyphenols Content, Antioxidant and Antimicrobial Activity of Ethanol Extracts from the Aerial Part of Rock Rose （Hefianthemum nummularium） Species

This study aimed to evaluate polyphenols content, antioxidant and antimicrobial activities of ethanol extract from rock rose （Helianthemum nummularium （L.） Mill.）. Plant material has been harvested in July from Romanian Carpathian Mountains. The ethanolic extract （70%, v/v） was prepared from the aerial part of rock rose species. High performance thin layer chromatography （HPTLC） analysis of ethanol extract and subsequently hydrolysed sample indicated that quercetin glycosides were the major polyphenolic compounds, and kaempferol derivates, chlorogenic and gallic phenylcarboxylic acids are also being present in the polar extracts. Chemiluminescence assay in luminol/H：O2 system indicated very high antioxidant activity of the ethanolic type of extract （ICs0 = 1.27 ~tg/mL）, while microbiological studies （cylinder method in plates） indicated certain antimicrobial activity （measuring from 12.5 mm to 21.5 mm of the diameter of the inhibition zone） of the propylene glycol （20%, v/v） standardized extract （5 mg gallic acid equivalents/mL sample） against several standard bacterial strains, Staphylococcus aureus ATCC 6538 and Escherichia coli ATCC 8739, Salmonella typhimurium ATCC 14028 and Salmonella enterritidis ATCC 13076, respectively. Therefore, based on the augmented antioxidant effect of the rock rose polar extracts, there can be found numerous applications in the pharmaceutical industry, but also in non-pharmaceutical fields, for example in cosmetic and hygiene products areas, due to certain antimicrobial properties.

Comparative Study on the Antibacterial Activity of Fresh and Fallen Leaves of Terminalia catappa L.

In the work reported here, the potential of different methods （cold and hot water, and ethanolic） of extraction of Indian almond （Terminalia catappa L.）, fresh and fallen leaves as an anti-bacterial agent was investigated. The hot water extract did not show any spectrum of activity against the selected bacteria while the cold water extract showed slight antibacterial activity suggesting that the effective components are heat labile. The ethanolic extracts of the leaves have higher antibiotic spectrum of activity than the cold water extract showing ethanol to be a better solvent in extracting the effective component. The fallen leaves seem to have a higher concentration of the effective component against the bacteria while ethanolic extract of the fresh leaves have similar spectrum of activity to Ciprofloxacin and Nitrofuratoin. These suggest that some effective components are lost when leaves fall off while some seem to increase in concentration. Fresh and fallen leaves contain tannin and flavonoids. In addition, the fallen leaves contain flavones. This might be responsible for the higher activity of fallen leaves extract observed against Pseudomonas and Staphylococcus spp. in our study. Combined use of extracts from fresh and fallen leaves broadened the spectrum of activity.

银纳米材料的形貌可控制备及电催化氧还原性能

应用多元醇法通过调控NaCl(间接晶种)的量,快捷方便地制备出银纳米线(SNWs)和银纳米粒子(SNPs),采用SEM、EDS、XRD和UV-Vis表征了纳米材料的形貌、元素组成、晶相结构和尺寸分布范围。结果表明,两种银纳米材料形貌均一,均为面心立方晶体结构。通过线性电位扫描法测定发现,SNWs和SNPs在碱性条件下对氧还原反应(ORR)具有不同的电催化活性,SNWs与SNPs对比,其起始还原电位正移70 mV,峰电位正移50 mV,还原峰电流前者是后者的1.8倍。SNWs表现出更好的催化性能。抗醇性能研究表明,SNWs对甲醇具有较好的抗醇性能,而SNPs对乙醇具有较好的抗醇性能,2种纳米材料均对异丙醇的抗醇性能均较差。