The aim of this work was to investigate the effect of lithium chloride (LiCl) on the fibre length distribution, melting temperature and the rheological characteristics of high yield pulp fibre reinforced polyamide biocomposite. The inorganic salt lithium chloride (LiCl) was used to decrease the melting and processing temperature of bio-based polyamide 11. The extrusion method and Brabender mixer approaches were used to carry out the compounding process. The densities and fibre content were found to be increased after processing using both compounding methods. The HYP fibre length distribution analysis realized using the FQA equipment showed an important fibre-length reduction after processing by both techniques. The rheological properties of HYP-reinforced net and modified bio-based polyamide 11 “PA11” (HYP/PA11) composite were investigated using a capillary rheometer. The rheological tests were performed in function of the shear rate for different temperature conditions. The low-temperature process compounding had higher shear viscosity; this was because during the process the temperature was low and the mixing and melting were induced by the high shear rate created during compounding process. Experimental test results using the extrusion process showed a steep decrease in shear viscosity with increasing shear rate, and this melt-flow characteristic corresponds to shear-thinning behavior in HYP/PA11, and this steep decrease in the melt viscosity can be associated to the hydrolyse reaction of nylon for high pulp fibre moisture content at high temperature. In addition to the low processing temperature, the melt viscosity of the biocomposite using the Brabender mixer approach increases with increasing shear rate, and this stability in the increase even at high shear rate for high pulp moisture content is associated to the presence of inorganic salt lithium chloride which creates the hydrogen bonds with pulp during the compounding process.
{"title":"Effect of Lithium Chloride on the Fibre Length Distribution, Processing Temperature and the Rheological Properties of High-Yield-Pulp-Fibre-Reinforced Modified Bio-Based Polyamide 11 Composite","authors":"Robenson Cherizol, M. Sain, J. Tjong","doi":"10.4236/ANP.2017.62005","DOIUrl":"https://doi.org/10.4236/ANP.2017.62005","url":null,"abstract":"The aim of this work was to investigate the effect of lithium chloride (LiCl) on the fibre length distribution, melting temperature and the rheological characteristics of high yield pulp fibre reinforced polyamide biocomposite. The inorganic salt lithium chloride (LiCl) was used to decrease the melting and processing temperature of bio-based polyamide 11. The extrusion method and Brabender mixer approaches were used to carry out the compounding process. The densities and fibre content were found to be increased after processing using both compounding methods. The HYP fibre length distribution analysis realized using the FQA equipment showed an important fibre-length reduction after processing by both techniques. The rheological properties of HYP-reinforced net and modified bio-based polyamide 11 “PA11” (HYP/PA11) composite were investigated using a capillary rheometer. The rheological tests were performed in function of the shear rate for different temperature conditions. The low-temperature process compounding had higher shear viscosity; this was because during the process the temperature was low and the mixing and melting were induced by the high shear rate created during compounding process. Experimental test results using the extrusion process showed a steep decrease in shear viscosity with increasing shear rate, and this melt-flow characteristic corresponds to shear-thinning behavior in HYP/PA11, and this steep decrease in the melt viscosity can be associated to the hydrolyse reaction of nylon for high pulp fibre moisture content at high temperature. In addition to the low processing temperature, the melt viscosity of the biocomposite using the Brabender mixer approach increases with increasing shear rate, and this stability in the increase even at high shear rate for high pulp moisture content is associated to the presence of inorganic salt lithium chloride which creates the hydrogen bonds with pulp during the compounding process.","PeriodicalId":71264,"journal":{"name":"纳米粒子(英文)","volume":"06 1","pages":"48-61"},"PeriodicalIF":0.0,"publicationDate":"2017-03-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42545050","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Murad M. A. Abualrejal, H. Zou, Jie Chen, Yanhua Song, Ye Sheng
Controlled synthesis of functional photoluminescent materials are of particular interest due to their fascinating optical properties. Herein, highly uniform SiO2:xTb3+spherical nanoparticles are fabricated by a facile sol-gel method. The structure, morphology, compositions, and luminescence properties of As-prepared samples were well investigated using TEM, SEM, EDX, XRD, XPS and luminescence spectroscopy. The PL intensity of SiO2:xTb3+spherical nanoparticles is Tb3+ ions concentration dependent achieved a maximum at 3 mol % of Tb3+. Particularly, SiO2:xTb3+spherical nanoparticles exhibit a green emission corresponding to 5D4→7Fj transition (541 nm) of Tb3+. These results show that As-prepared phosphors may find potential application in solid-state lighting fields.
{"title":"A Facile Synthesis and Photoluminescence Properties of SiO 2 :Tb 3+ Spherical Nanoparticles","authors":"Murad M. A. Abualrejal, H. Zou, Jie Chen, Yanhua Song, Ye Sheng","doi":"10.4236/ANP.2017.62002","DOIUrl":"https://doi.org/10.4236/ANP.2017.62002","url":null,"abstract":"Controlled synthesis of functional photoluminescent materials are of particular interest due to their fascinating optical properties. Herein, highly uniform SiO2:xTb3+spherical nanoparticles are fabricated by a facile sol-gel method. The structure, morphology, compositions, and luminescence properties of As-prepared samples were well investigated using TEM, SEM, EDX, XRD, XPS and luminescence spectroscopy. The PL intensity of SiO2:xTb3+spherical nanoparticles is Tb3+ ions concentration dependent achieved a maximum at 3 mol % of Tb3+. Particularly, SiO2:xTb3+spherical nanoparticles exhibit a green emission corresponding to 5D4→7Fj transition (541 nm) of Tb3+. These results show that As-prepared phosphors may find potential application in solid-state lighting fields.","PeriodicalId":71264,"journal":{"name":"纳米粒子(英文)","volume":"06 1","pages":"11-21"},"PeriodicalIF":0.0,"publicationDate":"2017-03-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49099995","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The mixture of Nano-graphite and organic vehicles doped to Nano-diamond paste. The suitable paste proportion was found. Nano-diamond film (NDF) was prepared by sol-gel coating method on ITO glass at 3000/min. The field emission characteristics of luminance-current, luminance-voltage and luminance-power of Nano-diamond film were analyzed and tested. Comparing these tested curves, the luminance was well proportional to current was got. Theoretic, the inner resistance of NDF field emission display (FED) consumes electric energy and real voltage change between the cathode and the anode of NDF-FED was very small after electrons emit. So the characteristic of NDF-FED was preferable to describe by luminance-current linear relationship, which was advantageous to device tested and designed.
{"title":"Preparation Nano-Diamond Film by Sol-Gelled Coating Method for Field Emission Display","authors":"Xiuxia Zhang, Shuyi Wei, Qianyu Ji","doi":"10.4236/ANP.2017.61001","DOIUrl":"https://doi.org/10.4236/ANP.2017.61001","url":null,"abstract":"The mixture of Nano-graphite \u0000and organic vehicles doped to Nano-diamond paste. The suitable paste proportion \u0000was found. Nano-diamond film (NDF) was prepared by sol-gel coating method on ITO \u0000glass at 3000/min. The field emission characteristics of luminance-current, luminance-voltage and luminance-power of Nano-diamond film were analyzed and tested. \u0000Comparing these tested curves, the luminance was well proportional to current \u0000was got. Theoretic, the inner resistance of NDF field emission display (FED) \u0000consumes electric energy and real voltage change between the cathode and the anode \u0000of NDF-FED was very small after electrons emit. So the characteristic of NDF-FED was preferable to describe by \u0000luminance-current linear relationship, which was advantageous to device \u0000tested and designed.","PeriodicalId":71264,"journal":{"name":"纳米粒子(英文)","volume":"06 1","pages":"1-9"},"PeriodicalIF":0.0,"publicationDate":"2017-02-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43841988","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A numerical analysis is performed to investigate the laminar, free convection flow in an Open Enclosure Using Lattice Boltzmann Method (LBM) in the presence of Carbon nanotube and Cu nanoparticles. The problem is studied for different volume fractions of nanoparticles, and aspect ratio of the cavity for various Rayligh numbers. The volume fraction of added nanoparticles to water (as base fluid) is lower than 1% to make dilute suspensions. The study presents a numerical treatment based on LBM to model convection heat transfer of Carbon nanotube based nanofluids. Results show that adding a low value of Carbon nanotube to the base fluid led to significant enhancement of convection rate. Results show that adding nanoparticles to the base fluid enhances the rate of natural convection in a cavity. Make a comparison between Carbon nanotube and Cu-nanoparticles shows that the Carbon nanotube-nano- particle has better performance to enhance convection rate at comparison with Cu- nanoparticles.
{"title":"Simulation of Natural Convection Heat Transfer Enhancement by Nanoparticles in an Open-Enclosure Using Lattice Boltzmann Method","authors":"M. Keshtkar","doi":"10.4236/ANP.2016.54020","DOIUrl":"https://doi.org/10.4236/ANP.2016.54020","url":null,"abstract":"A numerical analysis is performed to investigate the laminar, free convection flow in an Open Enclosure Using Lattice Boltzmann Method (LBM) in the presence of Carbon nanotube and Cu nanoparticles. The problem is studied for different volume fractions of nanoparticles, and aspect ratio of the cavity for various Rayligh numbers. The volume fraction of added nanoparticles to water (as base fluid) is lower than 1% to make dilute suspensions. The study presents a numerical treatment based on LBM to model convection heat transfer of Carbon nanotube based nanofluids. Results show that adding a low value of Carbon nanotube to the base fluid led to significant enhancement of convection rate. Results show that adding nanoparticles to the base fluid enhances the rate of natural convection in a cavity. Make a comparison between Carbon nanotube and Cu-nanoparticles shows that the Carbon nanotube-nano- particle has better performance to enhance convection rate at comparison with Cu- nanoparticles.","PeriodicalId":71264,"journal":{"name":"纳米粒子(英文)","volume":"05 1","pages":"187-198"},"PeriodicalIF":0.0,"publicationDate":"2016-09-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70338611","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
According to the extent of fungal infections, to be chronic these such diseases and recently the emerging issue of increased antibiotic resistance in fungal infections, most of scientists are going to find a proper way to replace antibacterial agent by significant semiconductor ZnO nanoparticles (NPs). They are well known to be one of the most important and special metal oxide nanoparticles in pharmaceutical against the most common fungi. ZnO nanoparticles were synthesized using sol-gel, hydrothermal and functionalized surface methods and formulated in water solutions as nanofluids. XRD, FTIR and SEM techniques and UV-Vis absorbance spectroscopy characterized their ZnO modified nanostructures. Also antimycotic potential according to generally tests such as: (MIC) minimum inhibitory concentration, (MFC) minimum fungicidal concentration and normally well diffusion method with standard strains fungi were performed. Among five common fungi strains using in this research, new various ZnO nanofluids showed noticeable results for dermatophyte fungi like Trichophyton mentagrophytes, Microsporum gypseum, Microsporum canis, Candida albicans and Candid tropicalis which had un growth zones in order 70, 40, 35, 30 and 30 mm in comparing with Clotrimazole reference reagent: 30, 25, 25, 18 and 20 mm by well method. The performance of MIC for ZnO nanofluids on fungi was determined to be equal to 0.35, 3.12, 6.25, 6.25 and 6.25 μgr/ml and MFC of nanoproducts showed the 1.5, 12.5, 25, 25 and 25 μgr/ml. Therefore, the designed ZnO nanofluids could reveal the most effect on fungi which cause dermal (ringworm), mucosal (thrush) and vaginal infections, so we are able to apply these surface high energetic ZnO water-based nanofluid formulations as in vitro nanomedicine and nanohygiene for the first time.
{"title":"The Interesting of Antifungal Effects of Novel In Vitro Fabrics of Stabilized ZnO Nanofluids","authors":"F. Katouzian, Z. Fakhroueian, S. M. Bidhendi","doi":"10.4236/ANP.2016.54022","DOIUrl":"https://doi.org/10.4236/ANP.2016.54022","url":null,"abstract":"According to the extent of fungal infections, to be chronic these such diseases and recently the emerging issue of increased antibiotic resistance in fungal infections, most of scientists are going to find a proper way to replace antibacterial agent by significant semiconductor ZnO nanoparticles (NPs). They are well known to be one of the most important and special metal oxide nanoparticles in pharmaceutical against the most common fungi. ZnO nanoparticles were synthesized using sol-gel, hydrothermal and functionalized surface methods and formulated in water solutions as nanofluids. XRD, FTIR and SEM techniques and UV-Vis absorbance spectroscopy characterized their ZnO modified nanostructures. Also antimycotic potential according to generally tests such as: (MIC) minimum inhibitory concentration, (MFC) minimum fungicidal concentration and normally well diffusion method with standard strains fungi were performed. Among five common fungi strains using in this research, new various ZnO nanofluids showed noticeable results for dermatophyte fungi like Trichophyton mentagrophytes, Microsporum gypseum, Microsporum canis, Candida albicans and Candid tropicalis which had un growth zones in order 70, 40, 35, 30 and 30 mm in comparing with Clotrimazole reference reagent: 30, 25, 25, 18 and 20 mm by well method. The performance of MIC for ZnO nanofluids on fungi was determined to be equal to 0.35, 3.12, 6.25, 6.25 and 6.25 μgr/ml and MFC of nanoproducts showed the 1.5, 12.5, 25, 25 and 25 μgr/ml. Therefore, the designed ZnO nanofluids could reveal the most effect on fungi which cause dermal (ringworm), mucosal (thrush) and vaginal infections, so we are able to apply these surface high energetic ZnO water-based nanofluid formulations as in vitro nanomedicine and nanohygiene for the first time.","PeriodicalId":71264,"journal":{"name":"纳米粒子(英文)","volume":"05 1","pages":"206-223"},"PeriodicalIF":0.0,"publicationDate":"2016-09-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70338739","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A direct synthesis method is introduced to prepare nano-porous silicon-nickel nanocomposite (nPS/Ni) powder for thermal isolation applications. In this paper, we study the thermal stability of nanocomposites consisting of nanoparticles metal incorporated into the pores of a porous silicon by a very simple method. The nickel element is chemically deposited whereas the nanoparticles are precipitated on the pore surfaces. The (nPS) and (nPS/Ni) nano-materials are thermally measured under nitrogen at temperatures of 40℃ - 1000℃, noticeable, demonstrating better thermal stability of (nPS/Ni) until 900℃ than in the case of (nPS) at 600℃. Then, the improving of the thermal stability of the nPS powder is facilitated using it in many applications of the thermal insulation process.
{"title":"Enhanced Thermal Stability of Promising Nano-Porous Silicon Powder","authors":"M. Nabil, H. Motaweh","doi":"10.4236/ANP.2016.54021","DOIUrl":"https://doi.org/10.4236/ANP.2016.54021","url":null,"abstract":"A direct synthesis method is introduced to prepare nano-porous silicon-nickel nanocomposite (nPS/Ni) powder for thermal isolation applications. In this paper, we study the thermal stability of nanocomposites consisting of nanoparticles metal incorporated into the pores of a porous silicon by a very simple method. The nickel element is chemically deposited whereas the nanoparticles are precipitated on the pore surfaces. The (nPS) and (nPS/Ni) nano-materials are thermally measured under nitrogen at temperatures of 40℃ - 1000℃, noticeable, demonstrating better thermal stability of (nPS/Ni) until 900℃ than in the case of (nPS) at 600℃. Then, the improving of the thermal stability of the nPS powder is facilitated using it in many applications of the thermal insulation process.","PeriodicalId":71264,"journal":{"name":"纳米粒子(英文)","volume":"16 1","pages":"199-205"},"PeriodicalIF":0.0,"publicationDate":"2016-09-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70338657","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A. N. Geraldes, A. A. A. Silva, Jessica Leal, G. M. Estrada-Villegas, N. Lincopán, K. Katti, Ademar Benévolo Lug atildeo
The advantage of using plants in nanoparticles synthesis is that they are easily available, safe to handle and possess a broad variability of metabolites such as antioxidants, nucleotides and vitamins. The aim of this study was to investigate the effects of Green and Zimbro tea and also Green coconut water as a reducing and stabilizer agent in gold nanoparticle synthesis. The gold nanoparticles were characterized by UV-Vis absorption spectroscopy, X-ray diffraction (XRD), Dynamic light scattering (DLS) and Transmission electron microscopy (TEM) analysis. Their physical stability was determined using a UV-Vis spectrophotometer over several days during storage at room temperature. We observed that green chemical process to obtain gold nanoparticles did not require any external chemicals reagent for stabilization of nanoparticulate. Absorption measurements indicated that the plasmon resonance wavelength appears around 530 nm. X-ray diffracto-grams of gold nanoparticles evidenced the presence of Au-rich (fcc) phases. TEM analysis showed a homogeneous dispersion of nanoparticles and some agglomerates. Differences in size and shape of the nanoparticles were observed. Zeta potential of AuNPs synthetized in presence of Green tea was -33 mV indicating stability of the synthesized nanoparticles.
{"title":"Green nanotechnology from plant extracts: synthesis and characterization of gold nanoparticles","authors":"A. N. Geraldes, A. A. A. Silva, Jessica Leal, G. M. Estrada-Villegas, N. Lincopán, K. Katti, Ademar Benévolo Lug atildeo","doi":"10.4236/ANP.2016.53019","DOIUrl":"https://doi.org/10.4236/ANP.2016.53019","url":null,"abstract":"The advantage of using plants in nanoparticles synthesis is that they are easily available, safe to handle and possess a broad variability of metabolites such as antioxidants, nucleotides and vitamins. The aim of this study was to investigate the effects of Green and Zimbro tea and also Green coconut water as a reducing and stabilizer agent in gold nanoparticle synthesis. The gold nanoparticles were characterized by UV-Vis absorption spectroscopy, X-ray diffraction (XRD), Dynamic light scattering (DLS) and Transmission electron microscopy (TEM) analysis. Their physical stability was determined using a UV-Vis spectrophotometer over several days during storage at room temperature. We observed that green chemical process to obtain gold nanoparticles did not require any external chemicals reagent for stabilization of nanoparticulate. Absorption measurements indicated that the plasmon resonance wavelength appears around 530 nm. X-ray diffracto-grams of gold nanoparticles evidenced the presence of Au-rich (fcc) phases. TEM analysis showed a homogeneous dispersion of nanoparticles and some agglomerates. Differences in size and shape of the nanoparticles were observed. Zeta potential of AuNPs synthetized in presence of Green tea was -33 mV indicating stability of the synthesized nanoparticles.","PeriodicalId":71264,"journal":{"name":"纳米粒子(英文)","volume":"5 1","pages":"176-185"},"PeriodicalIF":0.0,"publicationDate":"2016-07-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70338913","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
To improve the activity for glycerol oxidation reaction (GOR) of Pt, PtAg (mole ratio of Pt/Ag = 3 and 1) alloy nanoparticle-loaded carbon black (Pt/CB, PtAg(3:1)/CB, PtAg(1:1)/CB) catalysts were prepared by a wet method. The resultant catalysts, moreover, were heat-treated in a N2 atmosphere at 200°C. The alloying of Pt with Ag for each PtAg/CB was confirmed by X-ray diffractometry and electron dispersive X-ray spectrometry. The heat-treatment did not change the crystal structure of the PtAg alloys and increased their particle size. X-ray photoelectron spectroscopy exhibited that stabilizers were completely removed from the PtAg alloy surface, and the Pt4f and Ag3d doublets due to metallic Pt and Ag, respectively, shifted to lower binding energies, supporting the alloying of Pt with Ag. Both PtAg/CB electrodes had two oxidation waves of glycerol irrespective of heat-treatment, which was different from the Pt/CB electrode. The onset potential of the first oxidation wave was -0.60 V, which was 0.20 V less positive than that for the Pt/CB electrode, indicating the alloying of Pt with Ag greatly improved the GOR activity of Pt. The heat-treated PtAg(3:1)/ CB electrode improved the GOR current density of the second oxidation peak. In the potentiostatic electrolysis at -0.1 and 0 V for both PtAg/CB electrodes, the ratio of oxidation current density at 60 min to that at 5 min (j60/j5), an indicator of the catalyst deterioration, at 0 V was higher than that at -0.1 V, because the adsorbed oxidation intermediates were greatly consumed at the larger overpotential. The heat-treatment of the PtAg(3:1)/CB electrode increased the j60/j5 value at -0.1 V but decreased that at 0 V. This could be attributed to the formation of high-order oxidation intermediates which might have stronger poisoning effect.
{"title":"PtAg Nanoparticle Electrocatalysts for the Glycerol Oxidation Reaction in Alkaline Medium","authors":"B. Lam, Masanobu Chiku, E. Higuchi, H. Inoue","doi":"10.4236/ANP.2016.53018","DOIUrl":"https://doi.org/10.4236/ANP.2016.53018","url":null,"abstract":"To improve the activity for glycerol oxidation reaction (GOR) of Pt, PtAg (mole ratio of Pt/Ag = 3 and 1) alloy nanoparticle-loaded carbon black (Pt/CB, PtAg(3:1)/CB, PtAg(1:1)/CB) catalysts were prepared by a wet method. The resultant catalysts, moreover, were heat-treated in a N2 atmosphere at 200°C. The alloying of Pt with Ag for each PtAg/CB was confirmed by X-ray diffractometry and electron dispersive X-ray spectrometry. The heat-treatment did not change the crystal structure of the PtAg alloys and increased their particle size. X-ray photoelectron spectroscopy exhibited that stabilizers were completely removed from the PtAg alloy surface, and the Pt4f and Ag3d doublets due to metallic Pt and Ag, respectively, shifted to lower binding energies, supporting the alloying of Pt with Ag. Both PtAg/CB electrodes had two oxidation waves of glycerol irrespective of heat-treatment, which was different from the Pt/CB electrode. The onset potential of the first oxidation wave was -0.60 V, which was 0.20 V less positive than that for the Pt/CB electrode, indicating the alloying of Pt with Ag greatly improved the GOR activity of Pt. The heat-treated PtAg(3:1)/ CB electrode improved the GOR current density of the second oxidation peak. In the potentiostatic electrolysis at -0.1 and 0 V for both PtAg/CB electrodes, the ratio of oxidation current density at 60 min to that at 5 min (j60/j5), an indicator of the catalyst deterioration, at 0 V was higher than that at -0.1 V, because the adsorbed oxidation intermediates were greatly consumed at the larger overpotential. The heat-treatment of the PtAg(3:1)/CB electrode increased the j60/j5 value at -0.1 V but decreased that at 0 V. This could be attributed to the formation of high-order oxidation intermediates which might have stronger poisoning effect.","PeriodicalId":71264,"journal":{"name":"纳米粒子(英文)","volume":"05 1","pages":"167-175"},"PeriodicalIF":0.0,"publicationDate":"2016-07-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70338859","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This study was concentrated on the biosynthesis of silver nanoparticles from Penicillium aurantiogresium (IMI 89372) with a focus on its cytotoxicity in MCF-7 and MCT cancer cell lines as well as Vero (normal) cell line that was assessed by crystal violet assay after treatment with various concentrations (0.44 – 145 μg/ml) for 24 h. The cell morphology was examined by inverted light microscopy. Further, the radiosensitizing effect of silver nanoparticles (AgNPs) on MCF-7 was also demonstrated by assessing cell morphology, cell proliferation of MTT assay, LDH activity and induction of apoptosis through checking of some apoptotic genes that altered during carcinogenesis, including caspase-3, Bax and Bcl-2. Caspase-3 activity was also estimated. Synthesis of AgNPs was determined by UV-Visible spectrum and it was further characterized by TEM, FT-IR and X-Ray analysis (EDX, XRD). The biosynthesized AgNPs were spherical and of 12.7 nm in size as recorded by direct electron microscopy visualization. The biosynthesized AgNPs showed variation in cytotoxicity against MCF-7, MCT and Vero cell lines in a concentration dependant response with a varied degree of alteration in cell morphology. The result showed that AgNPs were highly toxic towards MCF-7 with IC50 value of 10.5 μg/ml. Treatment of MCF-7 (10.5 μg/ml) prior to irradiation improved the effect of irradiation dose (6 Gy) via increasing alteration of cell morphology, inhibition of cell proliferation, activation of the lactate dehydrogenase (LDH) and caspase-3 leading to induction of apoptosis which was further confirmed through increasing nuclear DNA damage and up regulation of caspase 3 and Bax genes and downrgulation of Bcl-2 genes. In conclusion, the present findings clearly indicated that AgNPs showed dose dependant cytotoxicity and verified that AgNPs acted as a potent radiosensitizer and could enhance gamma irradiation induced killing of MCF-7 breast cancer cells.
{"title":"Preparation, Characterization and in Vitro Evaluation of the Antitumor Activity of the Biologically Synthesized Silver Nanoparticles","authors":"Omama E. Elshawy, E. Helmy, L. Rashed","doi":"10.4236/ANP.2016.52017","DOIUrl":"https://doi.org/10.4236/ANP.2016.52017","url":null,"abstract":"This study was concentrated on the \u0000biosynthesis of silver nanoparticles from Penicillium aurantiogresium (IMI \u000089372) with a focus on its cytotoxicity in MCF-7 and MCT cancer cell lines as \u0000well as Vero (normal) cell line that was assessed by crystal violet assay after \u0000treatment with various concentrations (0.44 – 145 μg/ml) for 24 h. The cell \u0000morphology was examined by inverted light microscopy. Further, the \u0000radiosensitizing effect of silver nanoparticles (AgNPs) on MCF-7 was also \u0000demonstrated by assessing cell morphology, cell proliferation of MTT assay, LDH \u0000activity and induction of apoptosis through checking of some apoptotic genes \u0000that altered during carcinogenesis, including caspase-3, Bax and Bcl-2. \u0000Caspase-3 activity was also estimated. Synthesis of AgNPs was determined by \u0000UV-Visible spectrum and it was further characterized by TEM, FT-IR and X-Ray \u0000analysis (EDX, XRD). The biosynthesized AgNPs were spherical and of 12.7 nm in \u0000size as recorded by direct electron microscopy visualization. The biosynthesized \u0000AgNPs showed variation in cytotoxicity against MCF-7, MCT and Vero cell lines \u0000in a concentration dependant response with a varied degree of alteration in \u0000cell morphology. The result showed that AgNPs were highly toxic towards MCF-7 \u0000with IC50 value of 10.5 μg/ml. Treatment of MCF-7 (10.5 μg/ml) prior to \u0000irradiation improved the effect of irradiation dose (6 Gy) via increasing \u0000alteration of cell morphology, inhibition of cell proliferation, activation of \u0000the lactate dehydrogenase (LDH) and caspase-3 leading to induction of apoptosis \u0000which was further confirmed through increasing nuclear DNA damage and up \u0000regulation of caspase 3 and Bax genes and downrgulation of Bcl-2 genes. In \u0000conclusion, the present findings clearly indicated that AgNPs showed dose dependant \u0000cytotoxicity and verified that AgNPs acted as a potent radiosensitizer and \u0000could enhance gamma irradiation induced killing of MCF-7 breast cancer cells.","PeriodicalId":71264,"journal":{"name":"纳米粒子(英文)","volume":"05 1","pages":"149-166"},"PeriodicalIF":0.0,"publicationDate":"2016-05-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70338708","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
S. Benzitouni, M. Zaabat, A. Khial, D. Rechem, A. Benaboud, D. Bouras, A. Mahdjoub, M. Toubane, Raphael Coste
Porous Cu-doped SnO2 thin films were synthesized by the sol-gel dip-coating method for enhancing methanol sensing performance. The effect of Cu doping concentration on the SnO2 sensibility was investigated. XRD data confirm that the fabricated SnO2 films are polycrystalline with tetragonal rutile crystal structure. AFM and SEM micrographs confirmed the roughness and the porosity of SnO2 surface, respectively. UV-Vis spectrum shows that SnO2 thin films exhibit high transmittance in the visible region ~95%. The band gap (3.80 - 3.92 eV) and the optical thickness (893 - 131 nm) of prepared films were calculated from transmittance data. The sensing results demonstrate that SnO2 films have a high sensitivity and a fast response to methanol. In particular, 3% Cu-SnO2 films have a higher sensitivity (98%), faster response (10-2 s) and shorter recovery time (18 s) than other films.
{"title":"High Sensitivity of Porous Cu-Doped SnO2 Thin Films to Methanol","authors":"S. Benzitouni, M. Zaabat, A. Khial, D. Rechem, A. Benaboud, D. Bouras, A. Mahdjoub, M. Toubane, Raphael Coste","doi":"10.4236/ANP.2016.52016","DOIUrl":"https://doi.org/10.4236/ANP.2016.52016","url":null,"abstract":"Porous \u0000Cu-doped SnO2 thin films were synthesized by the sol-gel dip-coating method for \u0000enhancing methanol sensing performance. The effect of Cu doping concentration \u0000on the SnO2 sensibility was investigated. XRD data confirm that the fabricated \u0000SnO2 films are polycrystalline with tetragonal rutile crystal structure. AFM \u0000and SEM micrographs confirmed the roughness and the porosity of SnO2 surface, \u0000respectively. UV-Vis spectrum shows that SnO2 thin films exhibit high \u0000transmittance in the visible region ~95%. The band gap (3.80 - 3.92 eV) and the \u0000optical thickness (893 - 131 nm) of prepared films were calculated from \u0000transmittance data. The sensing results demonstrate that SnO2 films have a high \u0000sensitivity and a fast response to methanol. In particular, 3% Cu-SnO2 films \u0000have a higher sensitivity (98%), faster response (10-2 s) and shorter recovery \u0000time (18 s) than other films.","PeriodicalId":71264,"journal":{"name":"纳米粒子(英文)","volume":"05 1","pages":"140-148"},"PeriodicalIF":0.0,"publicationDate":"2016-05-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70338443","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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