Effect of Organic Substances on the γ-Ray Oxidation of Ferrous Sulfate

Dewhurst, H. A.

doi:10.1063/1.1748051

Cited by 36 publications

(13 citation statements)

References 10 publications

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“…In our work, there are several possible reasons for the observation of less damage and an enhanced degree of whiteness when ethanol–water mixtures are used during the bleaching process. Firstly, ethanol may accelerate the initial oxidation of ferrous ions during the oxidative bleaching process [66,67]. The effect of ethanol may be interpreted based on the mechanism given below.…”

Section: Resultsmentioning

confidence: 99%

Protective Bleaching of Camel Hair in a Neutral Ethanol–Water System

Xia

Zhang

et al. 2018

Polymers

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As conventional bleaching under alkaline conditions is chemically damaging to protein fibers, a three-stage protective bleaching process in neutral ethanol-water mixtures was proposed for camel hair using mordanting with ferrous salts, oxidative bleaching with hydrogen peroxide, and reductive bleaching with sodium hydrosulfite. The aim of this work was to improve the whiteness degree of camel hair without substantial tenacity loss. In addition, the roles of ethanol during the bleaching treatment were also examined by characterizing the fibers using scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier transform infrared (FTIR) spectroscopy, and X-ray diffraction. The whiteness degree and mechanical properties of camel hair bleached in the neutral ethanol-water system were significantly superior to those of fibers bleached by a conventional method. SEM images showed no visible cracks on the scales of fibers bleached in the ethanol-water system, whereas large grooves were observed on fibers bleached in aqueous solution. TEM images confirmed the positive influence of ethanol on the mordanting process, and FTIR spectra suggested that ethanol reduced the breakage of hydrogen bonds in the fibers during the oxidative bleaching process. These findings indicate the potential of this protective bleaching method for application to a broad range of other natural protein fibers.

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Section: Resultsmentioning

confidence: 99%

Protective Bleaching of Camel Hair in a Neutral Ethanol–Water System

Xia

Zhang

et al. 2018

Polymers

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“…Ethanol also enhances some radiationinduced reactions. Among these are the oxidation of ferrous sulfate (43) and the reduction of ceric sulfate (44), potassium dichromate (35), and diphosphopyridine nucleotide (41). In these cases, however, no change in the reactiondose relationship was observed, the reaction remaining a linear function of time.…”

Section: Discussionmentioning

confidence: 96%

The Inactivation of Dilute Solutions of Crystalline Trypsin by X-Radiation

McDonald

1955

The Journal of General Physiology

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Previous studies in this laboratory (1) on the inactivation of dilute solutions of crystalline trypsin in 0.005 N hydrochloric acid by x-radiation at room temperature showed that the reaction yield, that is, the number of micromoles of trypsin per liter inactivated per 1000 roentgens (r), increases markedly as the initial concentration of trypsin is increased from 0.1 to 200 micromolar (~) . On the other hand, Dale and his coworkers (2) demonstrated that the reaction yield for the inactivation of aqueous solutions of crystalline carboxypeptidase by x-rays is constant for concentrations of enzyme between 6 and 600 /~M. Only a slight rise in the reaction field for the inactivation of aqueous solutions of crystalline pepsin by high voltage electrons was observed by Bellamy and Lawton (3) when the concentration of pepsin was increased from 2.8 to 140 ~s. These are the only pure enzymes that have been studied extensively over a wide concentration range.Fricke's observations (4) on the reactivity of hydrochloric acid in radiation studies raised the question whether the continuous rise in reaction field with increasing concentration of trypsin obtained in the previous studies (1) was due to the presence of hydrochloric acid in the solutions. A detailed study was therefore made of the inactivation by x-radiation of dilute solutions of trypsin in diverse media under various experimental conditions. This showed that the chemical nature of the medium in which the trypsin is irradiated markedly affects the reaction field. When solutions of trypsin of various concentrations in 0.005 N hydrochloric, sulfuric, or nitric acid were irradiated, the reaction yields were found to increase as the concentration of enzyme was increased. The rise was less pronounced in the presence of sulfuric or nitric acid, however, than in the presence of hydrochloric acid. With concentrations of trypsin between 1 and 10/~M, the reaction yields obtained in 0.005 N hydrochloric acid

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“…Sensitivity is dependent on the pH of the Fricke solution also because pH affects the chemical yield of the water radiolytic products and the radiochemical yield of ferrous to ferric ion conversion. The radiochemical yield can be increased by the addition of aliphatic alcohols and benzoic acid [58,176]. Fricke solutions require high doses for the radiation-induced changes to be readily observed; however, these doses can be delivered in a short time with modern LINACs.…”

Section: Magnetic Resonance Imagingmentioning

confidence: 99%

Hydrogels for Three-Dimensional Ionizing-Radiation Dosimetry

Marrale

D’Errico

2021

Gels

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Radiation-sensitive gels are among the most recent and promising developments for radiation therapy (RT) dosimetry. RT dosimetry has the twofold goal of ensuring the quality of the treatment and the radiation protection of the patient. Benchmark dosimetry for acceptance testing and commissioning of RT systems is still based on ionization chambers. However, even the smallest chambers cannot resolve the steep dose gradients of up to 30–50% per mm generated with the most advanced techniques. While a multitude of systems based, e.g., on luminescence, silicon diodes and radiochromic materials have been developed, they do not allow the truly continuous 3D dose measurements offered by radiation-sensitive gels. The gels are tissue equivalent, so they also serve as phantoms, and their response is largely independent of radiation quality and dose rate. Some of them are infused with ferrous sulfate and rely on the radiation-induced oxidation of ferrous ions to ferric ions (Fricke-gels). Other formulations consist of monomers dispersed in a gelatinous medium (Polyacrylamide gels) and rely on radiation-induced polymerization, which creates a stable polymer structure. In both gel types, irradiation causes changes in proton relaxation rates that are proportional to locally absorbed dose and can be imaged using magnetic resonance imaging (MRI). Changes in color and/or opacification of the gels also occur upon irradiation, allowing the use of optical tomography techniques. In this work, we review both Fricke and polyacrylamide gels with emphasis on their chemical and physical properties and on their applications for radiation dosimetry.

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Effect of Organic Substances on the γ-Ray Oxidation of Ferrous Sulfate

Cited by 36 publications

References 10 publications

Protective Bleaching of Camel Hair in a Neutral Ethanol–Water System

Protective Bleaching of Camel Hair in a Neutral Ethanol–Water System

The Inactivation of Dilute Solutions of Crystalline Trypsin by X-Radiation

Hydrogels for Three-Dimensional Ionizing-Radiation Dosimetry

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