Decomposition of hydrogen peroxide on nickel(II) oxide irradiated by γ-radiation and by neutrons

1976 ◽  
Vol 41 (8) ◽  
pp. 2159-2163 ◽  
Author(s):  
V. Múčka
Keyword(s):  
Hydrogen Peroxide ◽  
Γ Radiation

Electron Spin Resonance Studies of Reactions of Photo-generated Organic Radicals with Hydrogen Peroxide in Aqueous Solution

1971 ◽  
Vol 49 (24) ◽  
pp. 4005-4016 ◽  
Author(s):  
C. E. Burchill ◽  
P. W. Jones
Keyword(s):  
Aqueous Solution ◽  
Hydrogen Peroxide ◽  
Free Radicals ◽  
Electron Spin Resonance ◽  
Organic Radicals ◽  
Chain Reaction ◽  
Direct Photolysis ◽  
Ketyl Radical ◽  
Γ Radiation ◽  
Spin Resonance

The reactions with H2O2 of free radicals derived from 2-propanol, methanol, dimethoxymethane, and tetrahydrofuran have been investigated by e.s.r. using in-cavity photolysis with acetone photosensitization to generate the radicals in flowing aqueous solutions. The variation in the concentrations of the radicals derived from a particular solute with addition of H2O2 is attributed to the selective oxidation of one radical by H2O2, propagating a secondary chain reaction, e.g.,[Formula: see text]The rate constant for the oxidation of the acetone ketyl radical ((CH3)2ĊOH) by H2O2 is estimated to be 5 × 105 M−1 s−1.The results and conclusions of this study are demonstrated to be consistent with the results of previous investigations employing γ-radiation, photolysis, and the reaction of Ti(III) with H2O2 for initiation.Results are also reported for the direct photolysis of aqueous malonic acid in the presence of H2O2.

Effect of External Gamma Irradiation on Dissolution of the UO2 Matrix

2004 ◽  
Vol 824 ◽  
Author(s):  
C. Jégou ◽  
B. Muzeau ◽  
V. Broudic ◽  
S. Peuget ◽  
A. Poulesquen ◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
Gamma Radiation ◽  
Gamma Irradiation ◽  
Dose Rate ◽  
Homogeneous Solution ◽  
Water Radiolysis ◽  
Γ Radiation ◽  
Alpha Emitters ◽  
Leaching Experiments ◽  
Alpha Radiolysis

AbstractLeaching experiments were done on UO2 pellets doped with alpha-emitters (238/239Pu, 1500 - year batch), in the presence of an external gamma irradiation source (A60Co = 260 Ci, γ dose rate = 650 Gy h−1). The effects of α and γ radiation and the nature of the cover gas (air or Ar + 4% H2) on water radiolysis, and on oxidizing dissolution of the UO2 matrix, are quantified and discussed. The cover gas clearly has a major role in the effect of γ radiolysis. The dissolution rate in an aerated medium is 83 mg m−2 d−1 compared with only 6 mg m−2 d−1 in Ar + 4% H2. The rate drop is accompanied by a reduction of about four orders of magnitude in the hydrogen peroxide concentrations in the homogeneous solution. The UO2 alteration rate under gamma radiation in Ar + 4% H2 is comparable to the rate obtained in the presence of alpha radiolysis alone for the doped UO2 pellets with the highest alpha activities (4.75 × 108 Bq/g UO2, 15 - year batch).

Peroxidase Localization in Hartmanella Trophozoites

1971 ◽  
Vol 29 ◽  
pp. 346-347 ◽  
Author(s):  
George E. Childs ◽  
Joseph H. Miller
Keyword(s):  
Hydrogen Peroxide ◽  
Ultrastructural Localization ◽  
Pathogenic Strain ◽  
Oxidative Enzymes ◽  
Differential Centrifugation ◽  
Electron Microscopic ◽  
Microscopic Studies ◽  
The Subject ◽  
Axenic Cultures

Biochemical and differential centrifugation studies have demonstrated that the oxidative enzymes of Acanthamoeba sp. are localized in mitochondria and peroxisomes (microbodies). Although hartmanellid amoebae have been the subject of several electron microscopic studies, peroxisomes have not been described from these organisms or other protozoa. Cytochemical tests employing diaminobenzidine-tetra HCl (DAB) and hydrogen peroxide were used for the ultrastructural localization of peroxidases of trophozoites of Hartmanella sp. (A-l, Culbertson), a pathogenic strain grown in axenic cultures of trypticase soy broth.

Fluorescent proteins for in vivo imaging, where's the biliverdin?

2020 ◽  
Vol 48 (6) ◽  
pp. 2657-2667
Author(s):  
Felipe Montecinos-Franjola ◽  
John Y. Lin ◽  
Erik A. Rodriguez
Keyword(s):  
Hydrogen Peroxide ◽  
In Vivo Imaging ◽  
Near Infrared ◽  
Fluorescent Protein ◽  
Fluorescent Proteins ◽  
Fluorescent Imaging ◽  
Infrared Light ◽  
Red Fluorescent Protein ◽  
Color Palette

Noninvasive fluorescent imaging requires far-red and near-infrared fluorescent proteins for deeper imaging. Near-infrared light penetrates biological tissue with blood vessels due to low absorbance, scattering, and reflection of light and has a greater signal-to-noise due to less autofluorescence. Far-red and near-infrared fluorescent proteins absorb light >600 nm to expand the color palette for imaging multiple biosensors and noninvasive in vivo imaging. The ideal fluorescent proteins are bright, photobleach minimally, express well in the desired cells, do not oligomerize, and generate or incorporate exogenous fluorophores efficiently. Coral-derived red fluorescent proteins require oxygen for fluorophore formation and release two hydrogen peroxide molecules. New fluorescent proteins based on phytochrome and phycobiliproteins use biliverdin IXα as fluorophores, do not require oxygen for maturation to image anaerobic organisms and tumor core, and do not generate hydrogen peroxide. The small Ultra-Red Fluorescent Protein (smURFP) was evolved from a cyanobacterial phycobiliprotein to covalently attach biliverdin as an exogenous fluorophore. The small Ultra-Red Fluorescent Protein is biophysically as bright as the enhanced green fluorescent protein, is exceptionally photostable, used for biosensor development, and visible in living mice. Novel applications of smURFP include in vitro protein diagnostics with attomolar (10−18 M) sensitivity, encapsulation in viral particles, and fluorescent protein nanoparticles. However, the availability of biliverdin limits the fluorescence of biliverdin-attaching fluorescent proteins; hence, extra biliverdin is needed to enhance brightness. New methods for improved biliverdin bioavailability are necessary to develop improved bright far-red and near-infrared fluorescent proteins for noninvasive imaging in vivo.

Protective effect of chitooligosaccharides on hydrogen peroxide-induced PC-12 cells death by inhibition of oxidative damage

2010 ◽  
Vol 34 (8) ◽  
pp. S27-S27
Author(s):  
Xueling Dai ◽  
Ping Chang ◽  
Ke Xu ◽  
Changjun Lin ◽  
Hanchang Huang ◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
Oxidative Damage ◽  
Protective Effect ◽  
Pc 12 Cells ◽  
Cells Death
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