Radiation Chemical Studies Research Articles

Formation of Hypophosphate in the Radiolysis of Phosphite Solution

Abstract The formation of hypophosphate and phosphate in the radiolysis of a phosphite solution was established by the anion-exchange chromatographic technique. The quantitative determination of their yields was made by colorimetry of the phosphate and hypophosphate with the Mo(V)+Mo(VI) reagent, which develops molybdenum-blue colors in two steps at different temperatures. The G values in an aerated condition are 0.01 molecules/100 eV in acid and 0.1 molecule/100 eV in neutral pH with respect to the hypophosphate formation, independent of the phosphite concentration. In a deaerated system much higher values are obtained, amounting to around 0.5 molecules/100 eV at a phosphite concentration of 10−3 m. The G values of hypophosphate plus phosphate are around 3.0; this is in agreement with the half-value of the primary radical yields, 1/2·(gred+gOH), reported in the data derived from the radiation-chemical studies in the aqueous system. The hypothesis that the hypophosphate (IV) ion radical is a transient species in the oxidation of phosphite to phosphate is supported by the results obtained in this work.

Radiation Chemical Studies with Cyclotron Beams, (I)

Systematic studies on the LET effect in the radiolysis of organic liquids have been initiated using various types of heavy ions accelerated by cyclotron. First, the effects of differences in irradiation conditions, in particular beam current, stirring speed and concentration of solutes have been examined. Aerated aqueous ferrous sulfate solutions (Fricke solutions) were subjected to irradiation by protons and He ions of various energies, to take advantage of the well-established reaction mechanism of the system. Experimental results obtained under various conditions were analyzed on the basis of the diffusion kinetics model. It was revealed that meticulous care must be taken to control the experimental conditions in studying radiolysis with heavy ions. The oxidation yields of ferrous ions were also determined as a function of linear energy transfer.

Radiation Chemical Studies with Cyclotron Beams, (I) Fricke Solution

Systematic studies on the LET effect in the radiolysis of organic liquids have been initiated using various types of heavy ions accelerated by cyclotron. First, the effects of differences in irradiation conditions, in particular beam current, stirring speed and concentration of solutes have been examined. Aerated aqueous ferrous sulfate solutions (Fricke solutions) were subjected to irradiation by protons and He ions of various energies, to take advantage of the well-established reaction mechanism of the system. Experimental results obtained under various conditions were analyzed on the basis of the diffusion kinetics model. It was revealed that meticulous care must be taken to control the experimental conditions in studying radiolysis with heavy ions. The oxidation yields of ferrous ions were also determined as a function of linear energy transfer.

Radiation chemical studies of protein reactions: Effect of amino acids on optical rotation

AbstractMonosodium 1‐glutamate, disodium inosine‐5′‐monophosphate, disodium guanosine‐5′‐monophosphate, calcium d‐pantothanate, 1‐arginine, and 1‐aspartic acid were found to protect the changes in the internal relationships of the atoms in the protein molecule from radiation damage. The behavior of the optical rotation was determined. The empirical equation for the protective effect is given by [α] f = b − a log X, where [α] f is the final specific rotation of the solution, X is the concentration of the amino acids, and a and b are adjustable constants.

Radiation chemical studies of protein reactions: Radiation dose and optical rotation

AbstractWhen protein was irradiated by gamma rays from a cobalt 60 sources, an activated state on the position of the groups in the vicinity of the asymmetric carbon atoms in the protein molecule was caused. An empirical equation for the change in optical rotation was obtained, and the phenomena were explained on the basis of the molecular mechanism. The general equation for the change in optical rotation is given by [α] = (b + a log R) (1 − e−kt), where [α] is the specific rotation of the solution, R is the gamma radiation dose, t is time, and a, b, and k are adjustable constants.

Radiation chemical studies of protein reactions: Effect of protectors on the breaking of secondary bonding in protein

AbstractRadiation protective effect of the breaking of secondary bonding in protein was examined with sodium benzoate, monosodium 1‐glutamate, 1‐arginine, and thiourea, and the behavior of viscosity against the protector was obtained. An experimental equation for the viscosity change is given by ηred = b − a log X, where ηred is the reduced viscosity of the solution, X is the protector concentration, and a and b are adjustable constants.

Radiation chemical studies of protein reactions: Effect of post‐irradiation on viscosity

AbstractProtein was irradiated by gamma rays from a cobalt 60 source. At different times after irradiation, the reactivity decay of the irradiated protein was examined. An empirical equation for the reactivity decay was obtained.

Radiation chemical studies of protein reactions: Effect of radiation on the breaking of secondary bonding in protein

AbstractThe effect of radiation on the breaking of secondary bonding in protein was studied by measuring the viscosity change at different radiation doses and urea concentrations. An experimental equation for the viscosity change was obtained, and the observed behavior was explained on the basis of the molecular mechanism. The general equation for the viscosity change is given by ηred = A(X − Be−kx) + C log R, where ηred is the reduced viscosity of the solution, R is the dose of γ‐radiation, X is the concentration of urea, and A, B, C, and k are adjustable constants.

Radiation chemical studies of protein reactions: Effect of irradiation liquid containing aromatic hydrocarbons and pH on viscosity

AbstractWhen protein is irradiated by γ‐rays from a 60Co source in various liquids containing aromatic hydrocarbons, such as benzene, naphthalene, and phenanthrene, the effect of the radiation varies with the irradiation liquids containing aromatic hydrocarbons. An empirical equation for the viscosity change was obtained. Protein irradiated by γ‐rays from a 60Co source in air showed the effect of pH on protein reactions. An empirical equation for the viscosity change was obtained.

Radiation chemical studies of protein reactions: Radiation dose and viscosity change

Journal of Applied Polymer ScienceVolume 12, Issue 12 p. 2747-2747 ErrataFree Access Radiation chemical studies of protein reactions: Radiation dose and viscosity change Mizuho Nisizawa, Mizuho Nisizawa Department of Chemistry, Defense Academy, Yokosuka, JapanSearch for more papers by this author Mizuho Nisizawa, Mizuho Nisizawa Department of Chemistry, Defense Academy, Yokosuka, JapanSearch for more papers by this author First published: December 1968 https://doi.org/10.1002/app.1968.070121222AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL No abstract is available for this article. Volume12, Issue12December 1968Pages 2747-2747 RelatedInformation

Radiation chemical studies of protein reactions: Effect of irradiation atmosphere on viscosity

AbstractWhen protein is irradiated by γ‐rays from a 60Co source in various atmospheres such as N2, CO2, H2, O2, and NH3, the effect of the radiation varies with the gases composing the irradiation atmosphere. An empirical equation for the viscosity change was obtained.

Radiation chemical studies of protein reactions: Effect of protectors against radiation

AbstractSodium glutamate and sodium benzoate were found to protect protein reactions from radiation damage. The behavior of the viscosity changes was determined. The experimental equation for the protective effect is given by ηred(∞) = a(log X)2 + b(log X) + c, where ηred(∞) is the reduced viscosity of the solution at infinite time X is the concentration of the radiation protectors, and a, b, and c are adjustable constants.

Radiation Chemical Studies with Particles of Very High Linear Energy Transfer

CHEMICAL substances have previously been irradiated by ion beams from high energy accelerators with particles of a maximum mean linear energy transfer (LET) (− dE/dx), in the irradiated material, of 20–30 eV/A, achieved with 4He ions of energy 1.0–1.5 MeV (refs. 1–3 and unpublished work by Burns and Reed) and with 12C ions of energy 50–100 MeV (ref. 4). The Harwell variable energy cyclotron5 can deliver ion beams that cover a very wide range in LET. We report the results of experiments done on this accelerator with 14N ions of 115 MeV and with 20Ne ions of 21 MeV. The mean LET of the latter particles in the substances used is ∼ 125 eV/A, about four times that of any previously reported radiation chemical study with ion beams. Results on benzene and cyclohexane with others for comparison are shown in Tables 1 and 2.

Radiation chemical studies of protein reactions: Radiation dose and viscosity change

AbstractWhen protein was irradiated by gamma rays from a cobalt 60 source, an activated state was caused. An empirical equation for the viscosity change was obtained, and the phenomena were explained on the basis of the molecular mechanism. The general equation for the viscosity change is given by ηred = (b + a log R)(1 − e−kt), where ηred is the reduced viscosity of the solution, R is the gamma radiation dose, and t is time.

Radiation chemical studies with heavy ion radiations

Radiation chemical studies with heavy ion radiations

Mass meter for an electromagnetic isotope separator

Laboratory isotope separators originated from the principles of mass spectrometry and have reached a level of sophistication sufficient for separating stable isotopes for use in many experiments and for separating radioactive isotopes of very short duration. There is continuous development of different components, such as ion sources, focusing elements, collection methods oriented to needs for high efficiency, less contamination, and high resolution. A separator in one form or other can perform the separation of isotopes and can be used as a low energy accelerator for other applications or as a high-intensity mass spectrometer. It is possible to interchange the components of a separator to use it as a high or low intensity machine and to use it as a separator or an accelerator. Its applications cover a broad area in physics, including atomic physics, solid-state physics, and nuclear physics. On-line isotope separators and separators for ion implantation are developing rapidly for fruitful research in nuclear physics and solid state electronics; the impact of the latter in the industrial field has shown promising results. Further applications of isotope separators in radiation damage studies, radiation chemistry and surface chemistry studies, and as injectors for accelerators illustrate the versatility of the instruments.

Energy-Partition Parameters in Radiation Studies of Molecular Gases

Ion-yield measurements in binary mixtures of 18 molecular gases are reported. They may be analyzed so as to yield a series of apparent molecular parameters, most generally interpreted as weighting coefficients for calculating dose partition in radiation chemistry studies of mixtures. The existence of a Jesse effect in an occasional molecular gas mixture is noted.

Reaction of OH radicals with nucleic acid bases--an E.S.R. study.

SummaryThe reactions of OH radicals with nucleic acid bases have been studied in aqueous solutions at pH 1 using electron-spin-resonance spectroscopy. It was found that the pyrimidine bases were more reactive than the purines and free radical products could only be detected in the pyrimidines. In thymine, cytosine and uracil, the OH radical added to the 5, 6 double bond. This confirms the conclusions of previous radiation chemical studies by other authors.

Measurement of absorbed dose of mixed-pile radiation in aqueous radiation chemistry

The problem of the measurement of the dose absorbed from mixed-pile radiations in aqueous radiation chemistry has been studied and the application of a calorimetric and chemical system has been considered in detail. The differential calorimeter described here permits simultaneous measurements of energy absorption in different materials. From these values it is possible to calculate the relative contributions of gammas and non-thermal neutrons to the total absorbed dose. The possibility of inserting a liquid sample into the calorimeter facilitates radiation chemical studies of aqueous solutions or, in general, liquid systems. The chemical system is oxalic acid in light- and heavy-water solutions. The radiation chemical yields have been measured under different working conditions. The possibility of using this chemical system for deriving relative contributions of different radiation components to the total absorbed dose is discussed.

Commentary on Scavenging Plots in Radiation Chemical Studies of Liquid Cyclohexane1

Commentary on Scavenging Plots in Radiation Chemical Studies of Liquid Cyclohexane¹