Search results for "OXIDATION"

From Seeds to Islands: Growth of Oxidized Graphene by Two-Photon Oxidation

2016

The mechanism of two-photon induced oxidation of single-layer graphene on Si/SiO2 substrates is studied by atomic force microscopy (AFM) and Raman microspectroscopy and imaging. AFM imaging of areas oxidized by using a tightly focused femtosecond laser beam shows that oxidation is not homogeneous but oxidized and nonoxidized graphene segregate into separate domains over the whole irradiated area. The oxidation process starts from point-like “seeds” which grow into islands finally coalescing together. The size of islands before coalescence is 30–40 nm, and the density of the islands is on the order of 1011 cm–2. Raman spectroscopy reveals growth of the D/G band ratio along the oxidation. Sha…

Oxidation of silicon nanoparticles produced by ns laser ablation in liquids

2014

The investigation of nanoparticles produced by ns pulsed Nd:YAG laser ablation of silicon in liquids is reported. Combined characterization by morphological and structural techniques shows that these nanoparticles have a mean diameter of ~3 nm and a core-shell structure consisting of a Si-nanocrystal surrounded by a layer of oxidized Si. Time resolved luminescence spectra evidence visible and UV emissions: a broad band around 1.9 eV originates from Si-nanocrystals, while two bands centered at 2.7 eV and 4.4 eV are associated with oxygen deficient centers in the SiO2 shell.

Revealing lattice disorder, oxygen incorporation and pore formation in laser induced two-photon oxidized graphene

2019

Laser induced two-photon oxidation has proven to be a reliable method to pattern and control the level of oxidation of single layer graphene, which in turn allows the development of graphene-based electronic and optoelectronic devices with an all-optical method. Here we provide a full structural and chemical description of modifications of air-suspended graphene during the oxidation process. By using different laser irradiation doses, we were able to show via transmission electron microscopy, electron energy loss spectroscopy, electron diffraction and Raman spectroscopy how graphene develops from its pristine form up to a completely oxidized, porous and amorphous carbon layer. Furthermore, …

Immunoaffinity purification and characterization of mitochondrial membrane-bound D-3-hydroxybutyrate dehydrogenase from Jaculus orientalis.

2008

Abstract Background The interconversion of two important energy metabolites, 3-hydroxybutyrate and acetoacetate (the major ketone bodies), is catalyzed by D-3-hydroxybutyrate dehydrogenase (BDH1: EC 1.1.1.30), a NAD+-dependent enzyme. The eukaryotic enzyme is bound to the mitochondrial inner membrane and harbors a unique lecithin-dependent activity. Here, we report an advanced purification method of the mammalian BDH applied to the liver enzyme from jerboa (Jaculus orientalis), a hibernating rodent adapted to extreme diet and environmental conditions. Results Purifying BDH from jerboa liver overcomes its low specific activity in mitochondria for further biochemical characterization of the e…

FUEL CELL POWERED WITH CANOLA OIL EMULSION

2017

The paper presents possibility of using canola oil as active substance to fuel cell powering. For this purpose a prototype fuel cell was built. Cell was powered with canola oil emulsion. As a detergent Syntanol DS-10 was used. The mesh electrode with Pt catalyst was used as a anode, and mesh electrode with Ni-Co catalyst was used as a cathode. The measurements conducted in the temperature range 293-333K. The maximum current density reached the level of 2 mA/cm2, and maximum power reached the level of 21 mW (at temp. 333K). So, the possibility of delivery of canola oil (in emulsion form) directly to the anode was shown. The obtain power is low, but was shown that it is possible to build the …

ELECTROOXIDATION OF USED SYNTHETIC ENGINE OIL IN AQUEOUS SOLUTION OF H2SO4

2017

The paper presents possibility of using used synthetic engine oil to direct electricity production. The measurements conducted in the temperature range 293-333 K. Were measured electrooxidation of used synthetic engine oil emulsion on a smooth platinum electrode in an aqueous solution of H2SO4. The emulsion prepared on the basis of a nonionic surfactant Syntanol DS-10. The maximum current density reached the level of 22 mA/cm2 (temp. 333 K). Measurements shows possibility of direct electricity production from used synthetic engine oil emulsion, so powering fuel cell of this oil.

Reductive modification of genetically encoded 3-nitrotyrosine sites in alpha synuclein expressed in E.coli

2019

Tyrosine nitration is a post-translational protein modification relevant to various pathophysiological processes. Chemical nitration procedures have been used to generate and study nitrated proteins, but these methods regularly lead to modifications at other amino acid residues. A novel strategy employs a genetic code modification that allows incorporation of 3-nitrotyrosine (3-NT) during ribosomal protein synthesis to generate a recombinant protein with defined 3-NT-sites, in the absence of other post-translational modifications. This approach was applied to study the generation and stability of the 3-NT moiety in recombinant proteins produced in E.coli. Nitrated alpha-synuclein (ASYN) was…

Special issue: Exercise redox biology from health to performance

2020

Electrochemical Oxidation of Hf-Nb Alloys as a Valuable Route to Prepare Mixed Oxides of Tailored Dielectric Properties

2018

Metal oxides with high dielectric constant are extensively studied in the frame of substituting SiO2 as gate dielectric in nanoelectronic devices. Here, high-k mixed HfO2/Nb2O5 oxides are prepared by a facile electrochemical route starting from sputtering-deposited Hf–Nb alloys with several compositions. Transmission electron microscopy, grazing incidence X-ray diffraction, and glow discharge optical emission spectroscopy are employed to study the oxide structures, disclosing a crystalline–amorphous transition of the electrochemically prepared oxides by increasing the Nb content. Photo-electrochemical measurements allow the observation of optical transitions ascribed to localized states ins…

Ruta chalepensis L. (Rutaceae) leaf extract: chemical composition, antioxidant and hypoglicaemic activities.

2017

Ruta chalepensis L. (Rutaceae) leaf extract was investigated for its chemical profile and antioxidant and hypoglycaemic properties. The antioxidant effects were investigated by 2,2-diphenyl-1-picrylhydrazyl (DPPH), Chi-carotene bleaching, and metal chelating activity assays. The carbohydrate-hydrolysing enzymes inhibition assay was used to test the hypoglycaemic potential. R. chalepensis showed a high content of hesperidin and rutin with values of 591.9 and 266.7 mg/g dry extract, respectively. The extract exhibited a promising protection of lipid peroxidation (IC50 value of 16.9 mu g/mL) and inhibited both alpha-amylase and alpha-glucosidase enzymes in a concentration-dependent manner. The…