Substances radiation effects

Radiation, of course, affects specific chemical substances present in biological systems. It appears evident that when the enzymic and hormonal levels of two individuals differ markedly in pattern by inheritance, there will be corresponding differences (as there are in mice) to radiation effects. 

All chemical reactions, whether of the hydrolysis, acid-base, or combustion type, take place at a definite rate and depend on the conditions of the system. The most important of these conditions are the concentration of the reactants, the temperature, radiation effects, and the presence of a catalyst or inhibitor. The rate of the reaction may be expressed in terms of the concentration of any of the reacting substances or of any reaction product that is, the rate may be expressed as the rate of decrease of the concentration of a reactant or the rate of increase of a reaction product. 

Inelastic photon scattering processes are also possible. In 1928, the Indian scientist C. V. Raman (who won the Nobel Prize in 1930) demonstrated a type of inelastic scattering that had already been predicted by A. Smekal in 1923. This type of scattering gave rise to a new type of spectroscopy, Raman spectroscopy, in which the light is inelastically scattered by a substance. This effect is in some ways similar to the Compton effect, which occurs as a result of the inelastic scattering of electromagnetic radiation by free electrons. 

The so-called first law of photochemistry stating that only the radiation absorbed by a molecular entity or substance is effective in producing a photochemical change. 

The density of a liquid is hundreds of times greater than that of a gas. The spatial inhomogeneity in the distribution of reagents is more pronounced here, the remains for quite a long time, therefore, the diffusion processes in condensed media proceed more slowly. As a result, the kinetics of reactions in a substance in the condensed phase is different than it is in gases, and gives a different final radiation effect. 

In view of the increasing ecological concern and crop production requirements, future research should be directed to understanding the role of plant growth substances in controlling or modifying 1) radiation effects, 2) mineral deficiences,... 

Krypton, Xenon, and Radon. Krypton and xenon, which occur in very small quantities in the air, have not found any significant use. Radon, which is produced steadily by radium, is used in the treatment of cancer. It has been found that the rays given off by radioactive substances are effective in controlling this disease. A convenient way ol administering this radiation is to pump the radon that has been produced by a sample of radium into a small gold tube, which is tlien placed in proximity to the tissues to be treated. 

Provides reviewed and summarized information on the reproductive risk of hundreds of chemical substances. Includes coverage of industrial and environmental chemicals, drugs, nutritional agents, and radiation. Effects noted on fertility (male and female), pregnancy, development, and lactation. Produced by the Reproductive Toxicology Center (RTC) of the Columbia Hospital for Women, Washington, DC (available by direct access to the RTC). 

Using the counter current ion migration process (1 -6), all the actinides in the waste are separated as group or individual in one stage yielding a high decontamination factor ( 5 10 ). The separation takes place in aqueous medium, which is less sensitive to the radiation effects than organic substances. The radiation products of the carboxylic acid solution (mainly acetic... 

Radiation Effects on Solutions of Polymyxin. The decrease in the content of polymyxin and its biological activity, as well as the results of analyses for free and amide-like ammonia, total content of carbonyl substances, and the content of individual amino acids in the hydrolysates of irradiated samples are summarized in Table I. 

Labeled compounds experience self-radiolysis induced by the radioactive decay. The extent of such radiation effects depends on the half-life, the decay energy, the specific activity of the sample, and the G-value for decomposition. The presence of other substances can considerably affect the amoimt of damage. Aromatic compounds such as benzene (as a solvent) can serve as a protective medium to minimize radiation self-decomposition, whereas water or oxygen enhance it. 

Mid-IR radiation corresponds to fundamental transitions in which one vibrational mode is excited from its lowest energy state to its first excited state. For routine analysis a spectrum is normally taken from 400 to 4000 cm The mid-IR spectrum of a substance is effectively a unique fingerprint that can be used for the purpose of identification by comparison with a reference spectrum. When no reference spectrum is available, an IR spectrum can be used to identify the presence of certain structural units that, irrespective of their molecular environment, give rise to characteristic spectral features in a narrow frequency range. 

A number of chemical substances are effective at blocking UV radiation. An opaque cream of zinc oxide and titanium dioxide is the most effective type of sunscreen. In addition, para-aminobenzoic acid (PABA), benzophenone, and cinnamates are commonly used to block UV radiation. Recently, there has been a move away from the use of PABA, though. It s somewhat toxic, and a significant number of individuals are allergic to it. 

One of the most important parameters controlling iodine volatility is sump water pH not only will the I2 hydrolysis equilibrium and the iodine partition coefficient be affected by this parameter, but the product yields of radiolytic reactions and the extent of formation of organoiodine compounds as well. Because of the lack of practical experience, the sump water pH to be expected under severe accident conditions has to be calculated on the basis of assumed concentrations of potential sump water ingredients. In Table 7.17. (according to Beahm et al., 1992) an overview of substances to be expected in the sump water, which would effect a shift in solution pH either to lower or to higher values, is given. Besides these chemical substances, radiation may also affect sump water pH irradiation of trisodium phosphate solution (5.3 kGy/h) was reported to decrease the pH from an initial value of 9.0 to about 4.0 after 60 hours of irradiation (Beahm et al., 1992). It is obvious that in such a complicated system definition of the sump water pH to be expected in a real severe reactor accident is a difficult task. Nonetheless, a model for calculation has been developed by Weber et al. (1992). 

There is considerable evidence that protection against radiation effects by sulfhydryl substances is a fairly general phenomenon and that both destructive and regenerative processes may be modified under these conditions (1). This is apparent particularly when protective effects can be quantitated in terms of radiation dose— biological response parameters. 

The concentrations of various substances in water in dissolved, colloidal, or suspended form are typically low but vary considerably. A hardness value of up to 400 ppm of calcium carbonate, for example, is sometimes tolerated in public supplies, whereas 1 ppm of dissolved iron would be imacceptable. In treated water for high-pressure boilers or where radiation effects are important, as in nuclear reactors, impurities are measured in very small units such as parts per billion (ppb) or 1 /ig of contaminant per hter of water. Water analysis for drinldng water supplies is concerned mainly with pollution and bacteriological tests. For industrial supphes a mineral analysis is of more interest The important constituents can be classified as follows [9] ... 

Solvent a substance that dissolves or disperses another substance Somatic effects the effects of radiation that are limited to the exposed person Source means either laser or laser-illuminated reflecting surface... 

Fukano K and Kageyama E, Study of radiation-induced polymerization of vinyl monomers adsorbed on inorganic substances. VII. Effect of pretreatment temperature of silica gel on styrene-silica gel system , J Polym Sci Polym Chem... 

Radiation, both in the uv and in the visible region, can have a highly destmctive effect by decomposing the dye molecule. Other substances, particularly water, can reinforce the photochemical effect of light. Once the dyed material fades, its original condition usually cannot be restored. 

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