Chemical toxicity of uranium hexafluoride compared to acute effects of radiation

Energy Technology Data Exchange (ETDEWEB)

McGuire, S.A.

1991-02-01

The chemical effects from acute exposures to uranium hexafluoride are compared to the nonstochastic effects from acute radiation doses of 25 rems to the whole body and 300 rems to the thyroid. The analysis concludes that an intake of about 10 mg of uranium in soluble form is roughly comparable, in terms of early effects, to an acute whole body dose of 25 rems because both are just below the threshold for significant nonstochastic effects. Similarly, an exposure to hydrogen fluoride at a concentration of 25 mg/m{sup 3} for 30 minutes is roughly comparable because there would be no significant nonstochastic effects. For times t other than 30 minutes, the concentration C of hydrogen fluoride considered to have the same effect can be calculated using a quadratic equation: C = 25 mg/m{sup 3} (30 min/t). The purpose of these analyses is to provide information for developing design and siting guideline based on chemical toxicity for enrichment plants using uranium hexafluoride. These guidelines are to be similar, in terms of stochastic health effects, to criteria in NRC regulations of nuclear power plants, which are based on radiation doses. 26 refs., 1 fig., 5 tabs.

Role of free radicals in radiation chemical aging

Energy Technology Data Exchange (ETDEWEB)

Greenstock, C L

1986-01-01

Ionizing radiation initiates chemical changes in DNA, phospholipid membranes and other critical cell targets, that, if allowed to accumulate unrepaired, may lead to aging and other chronic effects. The chemical effects are free radical mediated, the principal damaging species being radical OH and to a lesser extent O2-anion radical and the molecular product H/sub 2/O/sub 2/. Many compounds can act in combination with ionizing radiation, to amplify the potential oxidative stress. Chemicals, ultra-violet light, lipid peroxides and their breakdown products may increase the extent of acute and chronic radiobiological effects.

Radiation-chemical aspects of solid state hot atom chemistry

International Nuclear Information System (INIS)

Matsuura, T.; Collins, K.E.; Collins, C.H.

1984-01-01

The study of nuclear hot atom chemical (NHAC) processes occurring in solids is seriously limited by the lack of adequate methods for directly studying the chemical species containing hot atoms. In the present review the effects of ionizing radiation on parent and non-parent yields from solid state targets is surveyed and qualitative interpretations are given. After a few general remarks of the relationship of radiation chemistry to solid state NHAC, a detailed description of the radiation effects is given (radiation annealing, neutron activation, changes in separable yield). (Auth.)

Effect of nuclear radiation on the electrical properties of chemical double layer capacitors

International Nuclear Information System (INIS)

Laghari, J.R.; Hammoud, A.N.

1990-01-01

The effects of nuclear radiation on the electrical properties of chemical double layer capacitors are determined. The capacitors were irradiated in a 2-MW nuclear reactor to different fluence levels. The exposure rate was 2.2 x 10 10 n/cm 2 · s of thermal neutrons, 9.52 x 10 8 n/cm 2 · s of fast neutrons (> 2 MeV), and 1.47 x 10 6 rad/h of gamma radiation. The properties measured during and after irradiation included the capacitance, equivalent series resistance, and open-circuit voltage. The post-irradiation effect on the leakage current was also determined. It was found that while the capacitance increased during irradiation, the equivalent series resistance and the open-circuit voltage decreased slightly during irradiation. Changes in these properties were not permanent s was evident from post-irradiation measurements. The leakage current did not show any significant change with radiation. The results indicate that chemical double layer capacitors can be suitably used as backup power source in electronic equipment operating in a radiation environment with total fluences up to 4.05 x 10 14 n/cm 2

Biological radiation effects

International Nuclear Information System (INIS)

Gomes, R.A.

1976-01-01

The stages of processes leading to radiation damage are studied, as well as, the direct and indirect mechanics of its production. The radiation effects on nucleic acid and protein macro moleculas are treated. The physical and chemical factors that modify radiosensibility are analysed, in particular the oxygen effects, the sensibilization by analogues of nitrogen bases, post-effects, chemical protection and inherent cell factors. Consideration is given to restoration processes by excision of injured fragments, the bloching of the excision restoration processes, the restoration of lesions caused by ionizing radiations and to the restoration by genetic recombination. Referring to somatic effects of radiation, the early ones and the acute syndrome of radiation are discussed. The difference of radiosensibility observed in mammalian cells and main observable alterations in tissues and organs are commented. Referring to delayed radiation effects, carcinogeneses, alterations of life span, effects on growth and development, as well as localized effects, are also discussed [pt

Studies of radiation and chemical toxicity. Progress report

International Nuclear Information System (INIS)

1986-01-01

Annual report for the Studies of Radiation and Chemical Toxicity Program at the University of Rochester is presented. Progress is reported on four projects: Neurobehavorial Toxicity of Organometallic Fuel Additives, Mechanisms of Permanent and Delayed Pathologic Effects of Ionizing Radiation, Solid State Radiation Chemistry of the DNA Backbone, and Pulmonary Biochemistry

Radiation chemical synthesis

International Nuclear Information System (INIS)

Zagoretz, P.A.; Poluetkov, V.A.; Shostenko, A.G.

1986-01-01

The authors consider processes in radiation chemical synthesis which are being developed in various scientific-research organizations. The important advantages of radiation chlorination, viz. the lower temperature compared with the thermal method and the absence of dehydrochlorination products are discussed. The authors examine the liquid-phase chlorination of trifluorochloroethyltrichloromethyl ether to obtain the pentachloro-contining ether, trifluorodichloroethyltrichloromethyl ether. The authors discuss radiation synthesis processes that have be used formulated kinetic equations on which models have been based. It is concluded that the possibilities of preparative (micro- and low-tonnage) radiation synthesis are promising

Chemical protection against ionizing radiation

International Nuclear Information System (INIS)

Livesey, J.C.; Reed, D.J.

1987-01-01

Over 40 years have passed since the research of the Manhattan Project suggested the possibility of chemical protection against ionizing radiation. During that time, much has been learned about the nature of radiation-induced injury and the factors governing the expression of that injury. Thousands of compounds have been tested for radioprotective efficacy, and numerous theories have been proposed to account for these actions. The literature on chemical radioprotection is large. In this article, the authors consider several of the mechanisms by which chemicals may protect against radiation injury. They have chosen to accent this view of radioprotector research as opposed to that research geared toward developing specific molecules as protective agents because they feel that such an approach is more beneficial in stimulating research of general applicability. This paper describes the matrix of biological factors upon which an exogenous radioprotector is superimposed, and examines evidence for and against various mechanisms by which these agents may protect biological systems against ionizing radiation. It concludes with a brief outlook for research in chemical radioprotection

Radiation, chemicals, and occupational health research

International Nuclear Information System (INIS)

Turner, J.E.

1984-01-01

Radiation protection and its interplay with physical research programs are described. Differences and similarities between problems in health protection for chemicals and for radiation are discussed. The importance of dosimetry in radiation work and its relevance to chemicals are cited. A collaborative program between physical and biological scientists on the toxicity of metals is briefly described. It serves as an example of new research directed toward the development of fundamental concepts and principles as a basis for understanding and controlling occupational and population exposures to chemicals. 12 references, 4 figures

Chemical protection and sensitization to ionizing radiation:molecular investigations

International Nuclear Information System (INIS)

Badiello, R.

1980-01-01

Chemical radioprotection and radiosensitization are induced by the presence of certain chemical compounds, which reduce or enhance the effect of ionizing radiation on living organisms. Such substances are either naturally present or may be artificially introduced in the living cells. Chemical radioprotectors are interesting for possible application in the health protection of both professionally exposed workers and patients treated by radiation for diagnostic and thereapeutic purposes. Interest in chemical radiosensitization has increased recently because of its potential application in the radiotherapy of tumours. Both radioprotection and radiosensitization occur by means of complicated mechanisms, which at first correspond to very fast reactions. The mechanism of the interaction between such substances and radiation-induced biological radicals has been investigated by means of pulse radiolysis and rapid mixing techniques. Examples of the application of these techniques are given to illustrate how information has been obtained on the molecular basis of radiation chemical modi-fication at the cellular level. In particular some interactions between model systems of biological interest (DNA, DNA components, enzymes, amino acids, etc.) and sulphur-containing radioprotectors (glutathione, cysteine, etc.) and/or electroaffinic radiosensitizers, are described. (H.K.)

Effect of crosslinking on the physico-chemical properties of radiation grafted PEM fuel cell membranes

International Nuclear Information System (INIS)

Mohamed Mahmoud Nasef; Hamdani Saidi

2006-01-01

The effect of crosslinking on the physico-chemical properties of radiation grafted proton conducting membranes (PFA-g-PSSA) was investigated. The membranes were prepared by radiation induced grafting of styrene/divinylbenzene (DVB) mixtures onto poly (tetrafluoroethylene-co-perfluorovinyl either) (PFA) films followed by sulfonation reactions. The variation of DVB content in the grafting mixture was in the range of 1-4 vol %. The equivalent weight, swelling, behavior and the proton conductivity of crosslinked membranes having equal degrees of grafting prepared found to be dependent predominantly on the level of crosslinking. The obtained membranes were found to posses a good combination of physico-chemical properties that is matching the commercial Nation 117 membranes

Chemical effects and their consequences for individuals occupationally exposed to ionizing radiation

International Nuclear Information System (INIS)

Salvador, C.; Kahl, G.G.; Kühn, P.; Zottis, A.D.; Flôr, R.C.

2017-01-01

By legal determination, workers exposed to ionizing radiation should use individual dosimeters in the most exposed region of the body, designed to estimate the effective dose, as well as radiation protective clothing to minimize occupational exposures. Regarding dosimetry, in most cases it is perceived that the monthly values of exposure are within the limits of normality, however, even being below the limit can not rule out the possibility of damage that the low dose of ionizing radiation can cause. The objective of this article is to highlight the main chemical effects caused by exposure to ionizing radiation, especially biochemical damage in DNA, chromosomal aberrations and the correlation with the exposure of occupationally exposed individuals, as well as individuals from the public. A bibliographic search was carried out in indexed databases from February to April 2017 with the following descriptors: Radiation Ionizing, DNA Damage and Occupational Exposure. In the 'Science Direct' database were found 1205 articles, in the 'Scopus' 19 articles, in the 'Web of Science' 83 articles, in the 'PubMed' 22 articles and in the 'VHL' 60 articles related to the theme. It was concluded that exposure to ionizing radiation can affect the DNA molecule despite its repair mechanisms, which may result in genotoxicity. It has been reported a correlation between occupationally exposed individuals and chromosomal aberrations, demonstrating that even low doses of ionizing radiation can compromise the genetic material integrity of exposed workers, leading to the need for a periodic cytogenetic study for this group of workers

Is ionizing radiation regulated more stringently than chemical carcinogens

International Nuclear Information System (INIS)

Travis, C.C.; Pack, S.R.; Hattemer-Frey, H.A.

1989-01-01

It is widely believed that United States government agencies regulate exposure to ionizing radiation more stringently than exposure to chemical carcinogens. It is difficult to verify this perception, however, because chemical carcinogens and ionizing radiation are regulated using vastly different strategies. Chemical carcinogens are generally regulated individually. Regulators consider the risk of exposure to one chemical rather than the cumulative radiation exposure from all sources. Moreover, standards for chemical carcinogens are generally set in terms of quantities released or resultant environmental concentrations, while standards for ionizing radiation are set in terms of dose to the human body. Since chemicals and ionizing radiation cannot be compared on the basis of equal dose to the exposed individual, standards regulating chemicals and ionizing radiation cannot be compared directly. It is feasible, however, to compare the two sets of standards on the basis of equal risk to the exposed individual, assuming that standards for chemicals and ionizing radiation are equivalent if estimated risk levels are equitable. This paper compares risk levels associated with current standards for ionizing radiation and chemical carcinogens. The authors do not attempt to determine whether either type of risk is regulated too stringently or not stringently enough but endeavor only to ascertain if ionizing radiation is actually regulated more strictly than chemical carcinogens

Effects of radiation on the chemical environment surrounding waste canisters in proposed repository sites and possible effects on the corrosion process

International Nuclear Information System (INIS)

Glass, R.S.

1981-12-01

This report explores the interaction of ionizing radiation with various environments. In particular, worst case (aqueous) environments for the proposed nuclear waste repository sites are considered. Emphasis is on the fundamental chemical and physical processes involved. The identities of possible radiolysis products (both transient and stable) have been sought through a literature search. The effect of radiation on corrosion processes is discussed. The radiation-induced chemical environment in the worst case repository sites is not well defined. Attention should therefore be given to fundamental studies exploring the interaction of such environments with components of the nuclear waste package, including the canister materials and backfills. Identification and quantification of radiolysis products would be helpful in this regard

Chemical protection against ionizing radiation. Final report

International Nuclear Information System (INIS)

Livesey, J.C.; Reed, D.J.; Adamson, L.F.

1984-08-01

The scientific literature on radiation-protective drugs is reviewed. Emphasis is placed on the mechanisms involved in determining the sensitivity of biological material to ionizing radiation and mechanisms of chemical radioprotection. In Section I, the types of radiation are described and the effects of ionizing radiation on biological systems are reviewed. The effects of ionizing radiation are briefly contrasted with the effects of non-ionizing radiation. Section II reviews the contributions of various natural factors which influence the inherent radiosensitivity of biological systems. Inlcuded in the list of these factors are water, oxygen, thiols, vitamins and antioxidants. Brief attention is given to the model describing competition between oxygen and natural radioprotective substances (principally, thiols) in determining the net cellular radiosensitivity. Several theories of the mechanism(s) of action of radioprotective drugs are described in Section III. These mechanisms include the production of hypoxia, detoxication of radiochemical reactive species, stabilization of the radiobiological target and the enhancement of damage repair processes. Section IV describes the current strategies for the treatment of radiation injury. Likely areas in which fruitful research might be performed are described in Section V. 495 references

Chemical protection against ionizing radiation. Final report

Energy Technology Data Exchange (ETDEWEB)

Livesey, J.C.; Reed, D.J.; Adamson, L.F.

1984-08-01

The scientific literature on radiation-protective drugs is reviewed. Emphasis is placed on the mechanisms involved in determining the sensitivity of biological material to ionizing radiation and mechanisms of chemical radioprotection. In Section I, the types of radiation are described and the effects of ionizing radiation on biological systems are reviewed. The effects of ionizing radiation are briefly contrasted with the effects of non-ionizing radiation. Section II reviews the contributions of various natural factors which influence the inherent radiosensitivity of biological systems. Inlcuded in the list of these factors are water, oxygen, thiols, vitamins and antioxidants. Brief attention is given to the model describing competition between oxygen and natural radioprotective substances (principally, thiols) in determining the net cellular radiosensitivity. Several theories of the mechanism(s) of action of radioprotective drugs are described in Section III. These mechanisms include the production of hypoxia, detoxication of radiochemical reactive species, stabilization of the radiobiological target and the enhancement of damage repair processes. Section IV describes the current strategies for the treatment of radiation injury. Likely areas in which fruitful research might be performed are described in Section V. 495 references.

Radiation effects and radioprotectors

Energy Technology Data Exchange (ETDEWEB)

Purohit, R.K., E-mail: dr_rajendra_purohit@yahoo.co.in [Radiation Biology Laboratory, Department of Zoology, Govt. Dungar College, Bikaner (India); Bugalia, Saroj [Department of Zoology, S.K. Kalyan College, Sikar (India); Dakshene, Monika [Department of Chemistry, Govt. College, Kota (India)

2012-07-01

Radiation exposure causes damage to biological systems and these damages are mediated by the generation of free radicals and reactive oxygen species targeting vital cellular components such as DNA and membranes. DNA repair systems and the endogenous cellular biochemical defense mechanisms against reactive oxygen species and antioxidants enzymes like reduced Glutathione (GSH), Superoxide dismutase, Glutathione peroxidase catalase etc. fail upon exposures to higher as well as chronic radiation doses leading to alterations in cell functions, cell death or mutations. Radioprotectors prevent these alterations and protect cells and tissues from the deleterious effects of radiations. Radioprotectors are of great importance due to their possible and potential application during planned radiation exposures such as radiotherapy, diagnostic scanning, clean up operations in nuclear accidents, space expeditions etc. and Unplanned radiations exposures such as accidents in nuclear industry, nuclear terrorism, natural background radiation etc. Many of the available synthetic radioprotectors are toxic to mammalian system at doses required to be effective as radioprotector. Increasing uses of ionizing radiation have drawn the attention of many radiobiologists towards their undesired side effects produced in various tissues and for modifying them to facilitate the beneficial uses of radiation. Modification of radiation response is obtained by means of chemical substances that can significantly decrease the magnitude of response when present in a biological system during irradiation. Radioprotectors are chemicals that modify a cell's response to radiation. Radioprotectors are drugs that protect normal (non cancerous) cells from the damage caused by radiation therapy. These agents promote the repair of normal cells that are exposed to radiation. Various chemicals, like Cysteamine, MPG , WR-2721 have been tested for the protection against harmful effects of radiation. These radio

Radiation effects and radioprotectors

International Nuclear Information System (INIS)

Purohit, R.K.; Bugalia, Saroj; Dakshene, Monika

2012-01-01

Radiation exposure causes damage to biological systems and these damages are mediated by the generation of free radicals and reactive oxygen species targeting vital cellular components such as DNA and membranes. DNA repair systems and the endogenous cellular biochemical defense mechanisms against reactive oxygen species and antioxidants enzymes like reduced Glutathione (GSH), Superoxide dismutase, Glutathione peroxidase catalase etc. fail upon exposures to higher as well as chronic radiation doses leading to alterations in cell functions, cell death or mutations. Radioprotectors prevent these alterations and protect cells and tissues from the deleterious effects of radiations. Radioprotectors are of great importance due to their possible and potential application during planned radiation exposures such as radiotherapy, diagnostic scanning, clean up operations in nuclear accidents, space expeditions etc. and Unplanned radiations exposures such as accidents in nuclear industry, nuclear terrorism, natural background radiation etc. Many of the available synthetic radioprotectors are toxic to mammalian system at doses required to be effective as radioprotector. Increasing uses of ionizing radiation have drawn the attention of many radiobiologists towards their undesired side effects produced in various tissues and for modifying them to facilitate the beneficial uses of radiation. Modification of radiation response is obtained by means of chemical substances that can significantly decrease the magnitude of response when present in a biological system during irradiation. Radioprotectors are chemicals that modify a cell's response to radiation. Radioprotectors are drugs that protect normal (non cancerous) cells from the damage caused by radiation therapy. These agents promote the repair of normal cells that are exposed to radiation. Various chemicals, like Cysteamine, MPG , WR-2721 have been tested for the protection against harmful effects of radiation. These radio

The high pH chemical and radiation compatibility of various liner materials

International Nuclear Information System (INIS)

Whyatt, G.A.; Farnsworth, R.K.

1990-01-01

This paper reports on a flexible membrane liner that has been proposed to line a concrete vault in which liquid low-level radioactive waste will be solidified. High-density polyethylene (HDPE) and polypropylene liners were tested at the Pacific Northwest Laboratory in an EPA method 9090 format to determine their chemical compatibility with the waste. Radiation effects were also investigated. The liners were immersed in a highly caustic (pH>14), primarily inorganic solution at 90 degrees C. The liners were subjected to radiation doses up to 38.9 Mrad, which was the expected dose the liner would receive over a 30-year life inside the vault. Recent changes have placed the liner outside the vault. The acceptance criteria for judging the compatibility of the liner with radiation would be different that those used for judging chemical compatibility. The radiation damage over the life of the liner can be simulated in a short-term test. Both HDPE and polypropylene liners were judged to be acceptable from a chemical and radiation standpoint when placed outside of the vault, while several other liners were not compatible. Radiation did not have a significant effect on chemical degradation rates

The high pH chemical and radiation compatibility of various liner materials

International Nuclear Information System (INIS)

Whyatt, G.; Farnsworth, R.

1990-01-01

A flexible membrane liner has been proposed to line a concrete vault in which liquid low-level radioactive waste will be solidified. High-density polyethylene (HDPE) and polypropylene liners were tested at the Pacific Northwest Laboratory in an EPA method 9090 format to determine their chemical compatibility with the waste. Radiation effects were also investigated. The liners were immersed in a highly caustic (pH>14), primarily inorganic solution at 90 degrees C. The liners were subjected to radiation doses up to 38.9 Mrad, which was the expected dose the liner would receive over a 30-year life inside the vault. Recent changes have placed the liner outside the vault. The acceptance criteria for judging the compatibility of the liner with radiation should be different than those used for judging chemical compatibility. The radiation damage over the life of the liner can be simulated in a short-term test. Both HDPE and polypropylene liners were judged to be acceptable from a chemical and radiation standpoint when placed outside of the vault, while several other liners were not compatible. Radiation did not have a significant effect on chemical degradation rates

Biological Effects of Ionizing Radiation

Science.gov (United States)

Ingram, M.; Mason, W. B.; Whipple, G. H.; Howland, J. W.

1952-04-07

This report presents a review of present knowledge and concepts of the biological effects of ionizing radiations. Among the topics discussed are the physical and chemical effects of ionizing radiation on biological systems, morphological and physiological changes observed in biological systems subjected to ionizing radiations, physiological changes in the intact animal, latent changes following exposure of biological systems to ionizing radiations, factors influencing the biological response to ionizing radiation, relative effects of various ionizing radiations, and biological dosimetry.

The Effect of Gamma radiation, microwave radiation, their interaction and storage on chemical composition, antinutritional factors and the activities of trypsin inhibitor and lipoxygenase of soybean seeds

Energy Technology Data Exchange (ETDEWEB)

Abdel-Rahim, E A; Abdel-Fatah, O M [Dept. of Biochem., Faculty of Agric., Cairo University. (Egypt); El-Adawy, M; Badea, M Y [Food Technol. Dept., National Center for Research and Radiation Technol., Atomic Energy Authority (Egypt)

2000-07-01

The effect of gamma radiation, microwave radiation, interaction between them; and storage of radiated soybean seeds were investigated to find out the best treatment which had to the maximum reduction of antinutrional factors (Trypsin inhibitor and lipoxygenase activities) without significant effect on the chemical constituents. The gamma rays was used at three doses of 2.5, 5.0 and 8.0 kGy, microwave radiation was at 70 level power for 2 and 4 min; and the storage of seeds was at temperature, R.H. 50-55% for six months. The data revealed that, effects of interaction treatments were more effective than the treatment with microwave or gamma radiation alone.

The Effect of Gamma radiation, microwave radiation, their interaction and storage on chemical composition, antinutritional factors and the activities of trypsin inhibitor and lipoxygenase of soybean seeds

International Nuclear Information System (INIS)

Abdel-Rahim, E.A.; Abdel-Fatah, O.M.; El-Adawy, M.; Badea, M.Y.

2000-01-01

The effect of gamma radiation, microwave radiation, interaction between them; and storage of radiated soybean seeds were investigated to find out the best treatment which had to the maximum reduction of antinutrional factors (Trypsin inhibitor and lipoxygenase activities) without significant effect on the chemical constituents. The gamma rays was used at three doses of 2.5, 5.0 and 8.0 kGy, microwave radiation was at 70 level power for 2 and 4 min; and the storage of seeds was at temperature, R.H. 50-55% for six months. The data revealed that, effects of interaction treatments were more effective than the treatment with microwave or gamma radiation alone

Some chemical influence on genetic effects of ionizing radiation and biodosimetry problems

International Nuclear Information System (INIS)

Mosse, I.B.

2007-01-01

as by weak chemical mutagens or by many other factors and can change biodosimetry results. Some drugs, stress, virus diseases and so on can change biological effects of radiation too. So, many factors which are not under control can change significantly biological effects of radiation and by this way can be responsible for serious mistakes of individual biodosimetry. It is necessary to take into account that these factors are averaged over a population. That's why biological methods can be used for population radiation dose estimation but not for personal one.

Studies on chemical protectors against radiation, 18

International Nuclear Information System (INIS)

Shinoda, Masato; Ohta, Setsuko; Hayase, Yukitoshi

1978-01-01

Radiation protective effect of S,2-aminomethylisothiuronium bromide hydrobromide and 2-mercaptoethylamine hydrochloride was tested on mice irradiated with soft x-ray of 70 kVp, using life-prolongation effect as an index. These compounds showed a marked effect on mice irradiated with 11000--13000 R, using a 10 mm acrylate filter. This method seemed to be usable as a potency testing for chemical radioprotectors. (auth.)

Galaxy formation with radiative and chemical feedback

NARCIS (Netherlands)

Graziani, L.; Salvadori, S.; Schneider, R.; Kawata, D.; de Bennassuti, M.; Maselli, A.

Here we introduce GAMESH, a novel pipeline that implements self-consistent radiative and chemical feedback in a computational model of galaxy formation. By combining the cosmological chemical-evolution model GAMETE with the radiative transfer code CRASH, GAMESH can post-process realistic outputs of

Radiation-chemical alkylation of olefines with adamantane

International Nuclear Information System (INIS)

Podkhalyuzin, A.T.; Vikulin, V.V.; Morozov, V.A.; Nazarova, M.P.; Vereshchinskii, I.V.

1977-01-01

Radiation-chemical alkylation of C 2 to C 4 olefines with adamantane was studied in gas phase at temperatures 270 to 430 0 C. The main reaction product is monoalkyladamantane. The reaction proceeds by a free radical chain mechanism. The effective activation energy is of the order of 8 to 10 kcal/mole. Thermal alkylation was carried out for comparison and the contribution of the thermal component to the radiation-thermal process was estimated. Liquid phase alkylation of hexafluoropropylene with adamantane was studied in the presence of solvents. Under various conditions mono- and di-substituted adamantanes are produced containing fluorine in end groups. These compounds were converted to corresponding fluoroalkenyladamantanes by dehydrofluorination. The kinetic parameters were calculated and physical-chemical data concerning some of the resulting products were determined. (author)

Comparative efficiency of chemical and radiation mutagens on two Cicer arietinum Rhizobial strains

Energy Technology Data Exchange (ETDEWEB)

Khare, A K; Shinde, D A; Nayak, M L [Jawaharlal Nehru Krishi Vishwa Vidyalaya, Indore (India)

1982-03-01

A comparison of efficacy due to chemical and radiation mutagens on morphology, nutritional totipotence and symbiotic character of two Cicer arietinum rhizobia has been made. The mutants produced as a result of radiations (gamma and UV rays) differed from parents in that, the mutant colony size was bigger and gelatinase activity was higher. The mutants were not deficient nutritionally, had wider host range and the size and number of nodules produced were higher. Radiation mutagenic effects were more pronounced than chemical mutagens. The mutants derived from chemicals were not as efficient as radiation mutants although they were better than parents in total nodulation.

Effect of genes controlling radiation sensitivity on chemically induced mutations in Saccharomyces cerevisiae

International Nuclear Information System (INIS)

Prakash, L.

1976-01-01

The effect of 16 different genes (rad) conferring radiation sensitivity on chemically induced reversion in the yeast Saccharomyces cerevisiae was determined. The site of reversion used was a well-defined chain initiation mutant mapping in the structural gene coding for iso-1-cytochrome c. High doses of EMS and HNO 2 resulted in decreased reversion of cyc1-131 in rad6, rad9 and rad15 strains compared to the normal RAD + strains. In addition, rad52 greatly decreased EMS reversion of cyc1-131 but had no effect on HNO 2 -induced reversion; rad18, on the other hand, increased HNO 2 -induced reversion but did not alter EMS-induced reversion. When NQO was used as the mutagen, every rad gene tested, except for rad18, had an effect on reversion; rad6, rad9, rad15, rad17, rad18, rad22, rev1, rev2, and rev3 lowered NQO reversion while rad1, rad2, rad3, rad4, rad10, rad12, and rad16 increased it compared to the RAD + strain. The effect of rad genes on chemical mutagenesis is discussed in terms of their effect on uv mutagenesis. It is concluded that although the nature of the repair pathways may differ for uv- and chemically-induced mutations in yeast, a functional repair system is required for the induction of mutation by the chemical agents NQO, EMS, and HNO 2

Biological Effects of Radiation

International Nuclear Information System (INIS)

Jatau, B.D.; Garba, N.N.; Yusuf, A.M.; Yamusa, Y. A.; Musa, Y.

2013-01-01

In earlier studies, researchers aimed a single particle at the nucleus of the cell where DNA is located. Eighty percent of the cells shot through the nucleus survived. This contradicts the belief that if radiation slams through the nucleus, the cell will die. But the bad news is that the surviving cells contained mutations. Cells have a great capacity to repair DNA, but they cannot do it perfectly. The damage left behind in these studies from a single particle of alpha radiation doubled the damage that is already there. This proved, beyond a shadow of doubt, those there biological effects occur as a result of exposure to radiation, Radiation is harmful to living tissue because of its ionizing power in matter. This ionization can damage living cells directly, by breaking the chemical bonds of important biological molecules (particularly DNA), or indirectly, by creating chemical radicals from water molecules in the cells, which can then attack the biological molecules chemically. At some extent these molecules are repaired by natural biological processes, however, the effectiveness of this repair depends on the extent of the damage. The interaction of ionizing with the human body, arising either from external sources outside the body or from internal contamination of the body by radioactive materials, leads to the biological effects which may later show up as a clinical symptoms. Basically, this formed the baseline of this research to serve as a yardstick for creating awareness about radiation and its resulting effects.

Track models and radiation chemical yields

International Nuclear Information System (INIS)

Chatterjee, A.; Magee, J.L.

1987-01-01

The authors are concerned only with systems in which single track effects dominate and radiation chemical yields are sums of yields for individual tracks. The authors know that the energy deposits of heavy particle tracks are composed of spurs along the particle trajectory (about one-half of the energy) and a more diffuse pattern composed of the tracks of knock-on electrons, called the penumbra (about one-half of the energy). The simplest way to introduce the concept of a unified track model for heavy particles is to consider the special case of the track of a heavy particle with an LET below 0.2-0.3eV/A, which in practice limits us to protons, deuterons, or particles with energy above 100 MeV per nucleon. At these LET values, to a good approximation, spurs formed by the main particle track can be considered to remain isolated throughout the radiation chemical reactions

Effects of gamma radiations with or without chemical mutagens on rose seeds

International Nuclear Information System (INIS)

Lata, P.

1988-01-01

A preliminary experiment with seeds from 4 diploids, 17 tetraploids, 2 hexaploids and 1 octoploid roses confirmed that seed collection during early autumn under climatical conditions of London, gives a high percentage of viable seeds than those collected during late autumn. Seed stratification for about 100 days enhances germination when carried out under wet, purified sand. Harmful effects of radiations were recorded on seed germination, seedling survival, growth and flowering, after 0-120 Kr exposures of gamma rays. Rose cultivars were found to be more sensitive to radiations than the Rosa spp. The LD50 for diploid R. rugosa typica was between 20-30 Kr and for allo-tetraploid cultivar Aunty Dora, it was 8 Kr. No significant effect of radiations on seedling growth was recorded. Flowering in seedlings, raised from cultivar seeds, produced flowers during the first year of germination as compared with R. spp. seedlings which flowered after 3 to 4 years of germination. Among the chemical mutagens, Hydroxylamine produced least harmful effects on seed germination and survivals than those produced by Ethyl methane sulphonate; used alone or combined with low or high doses of radiations. The average seedling heights and number of leaves per seedlings were not affected. Mutagens were responsible for bringing about a loss in colour intensity which was more frequent when radiations and mutagens were used together. Real flower colour changes were rare and were attributed to the pollinating parent or mutagen or both. Present experiments indicate that although there are initial difficulties with seed germination but the resulting seedlings with increased genetic variability can generously reward a rose breeder in introducing new roses with rare combination of desirable characters which are difficult to accomplish merely by induced somatic mutations

Multiple stressor effects in Chlamydomonas reinhardtii--toward understanding mechanisms of interaction between effects of ultraviolet radiation and chemical pollutants.

Science.gov (United States)

Korkaric, Muris; Behra, Renata; Fischer, Beat B; Junghans, Marion; Eggen, Rik I L

2015-05-01

The effects of chemical pollutants and environmental stressors, such as ultraviolet radiation (UVR), can interact when organisms are simultaneously exposed, resulting in higher (synergistic) or lower (antagonistic) multiple stressor effects than expected based on the effects of single stressors. Current understanding of interactive effects is limited due to a lack of mechanism-based multiple stressor studies. It has been hypothesized that effect interactions may generally occur if chemical and non-chemical stressors cause similar physiological effects in the organism. To test this hypothesis, we exposed the model green alga Chlamydomonas reinhardtii to combinations of UVR and single chemicals displaying modes of action (MOA) similar or dissimilar to the impact of UVR on photosynthesis. Stressor interactions were analyzed based on the independent action model. Effect interactions were found to depend on the MOA of the chemicals, and also on their concentrations, the exposure time and the measured endpoint. Indeed, only chemicals assumed to cause effects on photosynthesis similar to UVR showed interactions with UVR on photosynthetic yield: synergistic in case of Cd(II) and paraquat and antagonistic in case of diuron. No interaction on photosynthesis was observed for S-metolachlor, which acts dissimilarly to UVR. However, combined effects of S-metolachlor and UVR on algal reproduction were synergistic, highlighting the importance of considering additional MOA of UVR. Possible mechanisms of stressor effect interactions are discussed. Copyright © 2015 Elsevier B.V. All rights reserved.

Multiple stressor effects in Chlamydomonas reinhardtii – Toward understanding mechanisms of interaction between effects of ultraviolet radiation and chemical pollutants

Energy Technology Data Exchange (ETDEWEB)

Korkaric, Muris [Eawag, Swiss Federal Institute of Aquatic Science and Technology, Department of Environmental Toxicology, 8600, Duebendorf (Switzerland); ETH Zürich, Institute of Biogeochemistry and Pollutant Dynamics, 8092 Zürich (Switzerland); Behra, Renata; Fischer, Beat B. [Eawag, Swiss Federal Institute of Aquatic Science and Technology, Department of Environmental Toxicology, 8600, Duebendorf (Switzerland); Junghans, Marion [Swiss Center for Applied Ecotoxicology Eawag-EPFL, 8600, Duebendorf (Switzerland); Eggen, Rik I.L., E-mail: rik.eggen@eawag.ch [Eawag, Swiss Federal Institute of Aquatic Science and Technology, Department of Environmental Toxicology, 8600, Duebendorf (Switzerland); ETH Zürich, Institute of Biogeochemistry and Pollutant Dynamics, 8092 Zürich (Switzerland)

2015-05-15

Highlights: • Systematic study of multiple stressor effects of UVR and chemicals in C. reinhardtii. • UVR and chemicals did not act independently on algal photosynthesis and reproduction. • Multiple stressor effects of UVR and chemicals depended on chemical MOA. • Synergistic effect interactions not limited to oxidative stress inducing chemicals. • Multiple MOAs of UVR may limit applicability of current prediction models. - Abstract: The effects of chemical pollutants and environmental stressors, such as ultraviolet radiation (UVR), can interact when organisms are simultaneously exposed, resulting in higher (synergistic) or lower (antagonistic) multiple stressor effects than expected based on the effects of single stressors. Current understanding of interactive effects is limited due to a lack of mechanism-based multiple stressor studies. It has been hypothesized that effect interactions may generally occur if chemical and non-chemical stressors cause similar physiological effects in the organism. To test this hypothesis, we exposed the model green alga Chlamydomonas reinhardtii to combinations of UVR and single chemicals displaying modes of action (MOA) similar or dissimilar to the impact of UVR on photosynthesis. Stressor interactions were analyzed based on the independent action model. Effect interactions were found to depend on the MOA of the chemicals, and also on their concentrations, the exposure time and the measured endpoint. Indeed, only chemicals assumed to cause effects on photosynthesis similar to UVR showed interactions with UVR on photosynthetic yield: synergistic in case of Cd(II) and paraquat and antagonistic in case of diuron. No interaction on photosynthesis was observed for S-metolachlor, which acts dissimilarly to UVR. However, combined effects of S-metolachlor and UVR on algal reproduction were synergistic, highlighting the importance of considering additional MOA of UVR. Possible mechanisms of stressor effect interactions are

Multiple stressor effects in Chlamydomonas reinhardtii – Toward understanding mechanisms of interaction between effects of ultraviolet radiation and chemical pollutants

International Nuclear Information System (INIS)

Korkaric, Muris; Behra, Renata; Fischer, Beat B.; Junghans, Marion; Eggen, Rik I.L.

2015-01-01

Highlights: • Systematic study of multiple stressor effects of UVR and chemicals in C. reinhardtii. • UVR and chemicals did not act independently on algal photosynthesis and reproduction. • Multiple stressor effects of UVR and chemicals depended on chemical MOA. • Synergistic effect interactions not limited to oxidative stress inducing chemicals. • Multiple MOAs of UVR may limit applicability of current prediction models. - Abstract: The effects of chemical pollutants and environmental stressors, such as ultraviolet radiation (UVR), can interact when organisms are simultaneously exposed, resulting in higher (synergistic) or lower (antagonistic) multiple stressor effects than expected based on the effects of single stressors. Current understanding of interactive effects is limited due to a lack of mechanism-based multiple stressor studies. It has been hypothesized that effect interactions may generally occur if chemical and non-chemical stressors cause similar physiological effects in the organism. To test this hypothesis, we exposed the model green alga Chlamydomonas reinhardtii to combinations of UVR and single chemicals displaying modes of action (MOA) similar or dissimilar to the impact of UVR on photosynthesis. Stressor interactions were analyzed based on the independent action model. Effect interactions were found to depend on the MOA of the chemicals, and also on their concentrations, the exposure time and the measured endpoint. Indeed, only chemicals assumed to cause effects on photosynthesis similar to UVR showed interactions with UVR on photosynthetic yield: synergistic in case of Cd(II) and paraquat and antagonistic in case of diuron. No interaction on photosynthesis was observed for S-metolachlor, which acts dissimilarly to UVR. However, combined effects of S-metolachlor and UVR on algal reproduction were synergistic, highlighting the importance of considering additional MOA of UVR. Possible mechanisms of stressor effect interactions are

Harmonization of risk management approaches: radiation and chemical exposures

Energy Technology Data Exchange (ETDEWEB)

Srinivasan, P. [Bhabha Atomic Research Centre, Radiation Safety Systems Div., Mumbai (India)

2006-07-01

Assessment of occupational and public risk from the environmental pollutants like chemicals, radiation, etc demands that the effects be considered not only from each individual pollutant, but from the combination of all the pollutants. An integrated risk assessment system needs to be in place to have an overall risk perspective for the benefit of policy makers and decision takers to try to achieve risk reduction in totality. The basis for risk-based radiation dose limits is derived from epidemiological studies, which provide a rich source of data largely unavailable to chemical risk assessors. In addition, use of the principle of optimization as expressed in the ALARA concept has resulted in a safety culture, which is much more than just complying with stipulated limits. The conservative hypothesis of no-threshold dose-effect relation (ICRP) is universally assumed. The end-points and the severity of different classes of pollutants and even different pollutants in a same class vary over a wide range. Hence, it is difficult to arrive at a quantitative value for the net detriment that weighs the various types of end-points and various classes of pollutants. Once the risk due to other pollutants is quantified by some acceptable methodology, it can be expressed in terms of the Risk Equivalent Radiation Dose (R.E.R.D.) for easy comparison with options involving radiation exposure. This paper is an effort to use to quantify and present the risk due to exposure to chemicals and radiation in a common scale for the purpose of easy comparison to facilitate decision taking. (authors)

Harmonization of risk management approaches: radiation and chemical exposures

International Nuclear Information System (INIS)

Srinivasan, P.

2006-01-01

Assessment of occupational and public risk from the environmental pollutants like chemicals, radiation, etc demands that the effects be considered not only from each individual pollutant, but from the combination of all the pollutants. An integrated risk assessment system needs to be in place to have an overall risk perspective for the benefit of policy makers and decision takers to try to achieve risk reduction in totality. The basis for risk-based radiation dose limits is derived from epidemiological studies, which provide a rich source of data largely unavailable to chemical risk assessors. In addition, use of the principle of optimization as expressed in the ALARA concept has resulted in a safety culture, which is much more than just complying with stipulated limits. The conservative hypothesis of no-threshold dose-effect relation (ICRP) is universally assumed. The end-points and the severity of different classes of pollutants and even different pollutants in a same class vary over a wide range. Hence, it is difficult to arrive at a quantitative value for the net detriment that weighs the various types of end-points and various classes of pollutants. Once the risk due to other pollutants is quantified by some acceptable methodology, it can be expressed in terms of the Risk Equivalent Radiation Dose (R.E.R.D.) for easy comparison with options involving radiation exposure. This paper is an effort to use to quantify and present the risk due to exposure to chemicals and radiation in a common scale for the purpose of easy comparison to facilitate decision taking. (authors)

Fabrication of radiation sources for educational purposes from chemical fertilizers using compressing and forming method

International Nuclear Information System (INIS)

Kawano, Takao

2008-01-01

Chemical fertilizers contain potassium, which is composed of a small amount of naturally occurring potassium-40. The potassium-40 radionuclide emits beta and gamma radiation. Three brands of chemical fertilizer were used to fabricate disk-shaped radiation sources and the fabricated radiation sources were examined for applicability to an educational radiation course. In the examination, tests to determine dependence of count rate on distance, shielding thickness, and shielding materials were conducted using the radiation sources. Results showed that radiation sources fabricated from the three brands of chemical fertilizer were equivalent for explaining radiation characteristics, particularly those related to the dependence of radiation strength on distance and shielding thickness. The relation between shielding effect and mass density can be explained qualitatively. Thus, chemical fertilizer radiation sources can be a useful teaching aid for educational courses to better promote understanding of radiation characteristics and the principles of radiation protection. (author)

Physical and chemical effects of ionizing radiation, application for conservation of food products

International Nuclear Information System (INIS)

Foos, J.

1986-01-01

The author sets about ''defining the parameters'' and ''describing the systems'' by means of which ionizing radiation can be used to conserve food products and make them more healthy. After defining the different types of radiation, he goes on to examine interactions between these types of radiation and the food to be processed, including the chemical reactions caused by the ionization and excitation processes [fr

Natural radiation sources fabricated from potassic chemical fertilizers and application to radiation education

International Nuclear Information System (INIS)

Kawano, Takao

2010-01-01

Potassic chemical fertilizers contain potassium, a small part of which is potassium-40. Since potassium-40 is a naturally occurring radioisotope, potassic chemical fertilizers are often used for demonstrations of the existence of natural radioisotopes and radiation. To fabricate radiation sources as educational tools, the compression and formation method developed by our previous study was applied to 13 brands of commercially available chemical fertilizers containing different amounts of potassium. The suitability (size, weight, and solidness) of thus fabricated sources was examined and 12 of them were selected as easy-to-use radiation sources at radiation educational courses. The radiation strength (radiation count rate measured by a GM survey meter) and potassium content of the 12 sources were examined. It was found that the count rate was wholly proportional to the percentage of potassium, and a new educational application was proposed and discussed for understanding that the substance emitting radiation must be the potassium present in the raw fertilizers. (author)

Human Genetic Marker for Resistance to Radiation and Chemicals

International Nuclear Information System (INIS)

Lieberman, Howard B.

2001-01-01

TO characterize the human HRDAD9 gene and evaluate its potential as a biomarker to predict susceptibility to the deleterious health effects potentially caused by exposure to radiations or chemicals present at DOE hazardous waste cleanup sites. HRAD9 is a human gene that is highly conserved throughout evolution. Related genes have been isolated from yeasts and mice, underscoring its biological significance. Most of our previous work involved characterization of the yeast gene cognate, wherein it was determined that the corresponding protein plays a significant role in promoting resistance of cells to radiations and chemicals, and in particular, controlling cell growth in response to DNA damage

Developmental effects of magnetic field (50 Hz) in combination with ionizing radiation and chemical teratogens.

Science.gov (United States)

Pafková, H; Jerábek, J; Tejnorová, I; Bednár, V

1996-11-01

The influence of a 50 Hz magnetic field (MF) on avian and mammalian embryogenesis, the MF level and vector, as well as the effect of exposure to MF (50 Hz, 10 mT) in combination with X-rays has been recently reported [2,3]. No significant alterations of chick or rat embryogenesis were found after repeated exposures to 50 Hz MF at 10 mT or 6 microT or with different vectors. However, X-ray chick embryotoxicity was significantly affected by repeated exposures of developing organisms to MF. A strong dependence of effect on the type of interaction was revealed. A decrease of X-ray induced teratogenicity was observed when MF preceded X-ray exposure (indirect interaction), while MF exposure applied immediately after X-ray radiation (direct interaction) non-significantly potentiated adverse developmental effects of ionizing radiation. This study deals with the effects of MF in combination with insulin or tetracycline. Exposure of chick embryos to MF influenced the sensitivity of embryonic morphogenetic systems to the subsequently administered chemical teratogens, insulin and/or tetracycline. A protective effect of MF was detected similarly as in the case of indirect interaction with ionizing radiation.

Radiation-chemical destruction of cellulose and other polysaccharides

International Nuclear Information System (INIS)

Ershov, B.G.

1998-01-01

The studies concerning the radiation-chemical destruction of cellulose, its ethers and some polysaccharides (xylan, starch, decstrans, chitin, chitosan and geparin) are discussed. Ionising irradiation causes the destruction of these compounds with the decay of pyranose ring, accompanied by the formation of compounds containing carbonyl or carboxyl groups, as well as hydrogen, carbon dioxide, and carbon oxide. The efficiency of radiation degradation increases with increasing the temperature and depends on the structure of polysaccharides and the nature of substituents. The mechanism of radiation-chemical transformations of cellulose and others polysaccharides is proposed. Prospects of the application of radiation-chemical methods of treatment of cellulose and other polysaccharides in industry and agriculture considered [ru

Radiation-dosimetry and chemical-toxicity considerations for 99Tc

International Nuclear Information System (INIS)

Coffey, J.L.; Hayes, R.L.; Rafter, J.J.; Watson, E.E.; Carlton, J.E.

1982-01-01

Technetium-99 (T/sub 1/2/ = 2.13 x 10 5 y) is produced in the fission of 235 U and 239 Pu. Technitium-99 has been found to contaminate some areas of the uranium re-enrichment process. ICRP-30 Part 2 gives the Annual Limit on Intake (ALI) for 99 Tc as 2 x 10 8 Bq (5.4 mCi) for class D inhaled material (IC80). The ICRP states clearly that ALIs are based on radiation risk only and that chemical toxicity is not considered (IC79). No data were found on the chemical toxicity of 99 Tc, possibly because there are no stable isotopes of technetium with which to study the toxicity, although, because of its long T/sub 1/2/, 99 Tc can, for all practical purposes, be considered stable. The ALI values for 99 Tc are based on data obtained using high specific activity /sup 99m/Tc (T/sub 1/2/ = 6 h) and /sup 95m/Tc (T/sub 1/2/ = 61 days). Since the specific activities of 99 Tc and Na 99 TcO 4 are quite low (17 mCi/g and 9 mCi/g, respectively) and 99 Tc is available in abundant supply, we have attempted to assess the relative radiation and chemical hazards that are associated with this radionuclide. The approach in this study was (1) to study the effect of chemical dose on the whole body retention of 99 Tc sodium pertechnetate in rats and to relate these effects to the radiation dose and the ALI and (2) to compare the chemical toxicity of 99 Tc sodium pertechnetate with the ALI at different chemical dose levels

How effects of chemicals might differ from those of radiations in giving rise to genetic ill-health in man

International Nuclear Information System (INIS)

Evans, H.J.

1980-01-01

Possible differences between the effects of the two groups of agents are considered. Two types of genetic damage are discussed. The first type involves mutational changes induced in germ cells or germ cell precursors which are then transmitted to the products of conception and to any resultant offspring and their descendants. The second kind is that damage sustained by the genome in somatic cells which is transmitted to daughter cells. Such somatic mutations are not heritable in the familiar sense, but they are transmitted to descendant cells within the body. It is concluded that a greater heterogeneity is expected in mutagenic response to chemical mutagens than to radiations in human populations, that the spectrum of mutations following chemical exposure may be quite different from that following radiation exposure, and that for many chemical agents, and in contrast to ionising radiations, one might expect a greater burden of genetic ill-health due to increased frequencies of mildly deleterious recessive and polygenic mutations. (Auth.)

Physical and chemical changes in water pollutants caused by ionizing radiations

International Nuclear Information System (INIS)

Vacek, K.

1978-01-01

Ionization and excitation as primary effects of ionizing radiation form secondary activated intermediary products (H and OH radicals and hydrated electrons esub(aq) - ) in water systems, which act on all in substances present in water. Physical and chemical changes speeding the sludge sedimentation in waste-water show complex dependences. It is, however, possible to prove them even at low radiation doses (0.07 to 0.35 kJ/kg). Chemical effects can be observed at higher radiation doses (1 to 10 kJ/kg) and are based on oxidative destruction of pollutants. Some of these reactions may be based on chain mechanisms (phenol oxidizing in water), but there are limited chances for application of these chain mechanisms in waste-water systems. Slight damage of biologically important macromolecules leads to changes, or even stops biological processes. Therefore, biological effects of ionizing radiation have the most remarkable impact. The utilization of these reactions in water management may be possible in suppressing biological ochration (ochre sedimentation) in wells and for ensuring hygienic conditions of sludge in waste-water processing for agrotechnical purposes. (author)

Climate-chemical interactions and greenhouse effects of trace gases

Science.gov (United States)

Shi, Guang-Yu; Fan, Xiao-Biao

1994-01-01

A completely coupled one-dimensional radiative-convective (RC) and photochemical-diffusion (PC) model has been developed recently and used to study the climate-chemical interactions. The importance of radiative-chemical interactions within the troposphere and stratosphere has been examined in some detail. We find that increases of radiatively and/or chemically active trace gases such as CO2, CH4 and N2O have both the direct effects and the indirect effects on climate change by changing the atmospheric O3 profile through their interaction with chemical processes in the atmosphere. It is also found that the climatic effect of ozone depends strongly on its vertical distribution throughout the troposphere and stratosphere, as well on its column amount in the atmosphere.

Effect of genes controlling radiation sensitivity on chemical mutagenesis in yeast

International Nuclear Information System (INIS)

Prakash, L.

1975-01-01

Ultraviolet radiation, x radiation, nitrogen mustard, methyl methanesulfonate, and dimethyl sulfate were found to revert all the tester strains with the same efficiency or without any dependence on simple types of base-pair changes, and it was concluded that these mutagens were nonspecific in the types of base-pair changes produced. The cycl-131 tester was used in studies designed to determine the genetic control of mutation induction using a variety of mutagens. The rad 6 and rad g genes greatly reduce the frequency of chemically induced reversion of cycl-131

Effects of ionizing radiations

International Nuclear Information System (INIS)

Gaussens, G.

1984-08-01

After recalling radiation-matter interaction, influence on radiation effects of chemical composition, structure, irradiation atmosphere, dose rate, temperature of organic materials and evolution of electrical, mechanical and physical properties are reviewed. Then behaviour under irradiation of main organic materials: elastomers, thermoplastics, thermosetting plastics, oils and paints are examined. 68 refs [fr

Radiation chemical studies on the electron-beam treatment of exhaust gases

International Nuclear Information System (INIS)

Washino, Masamitsu; Tokunaga, Okihiro; Nishimura, Koichi; Suzuki, Nobutake

1980-03-01

This report summarizes the radiation chemical studies on the synthetic models of exhaust gases which has been done in JAERI-Takasaki. Radiation-induced reactions of low concentrations of SO 2 and NO was studied in dry and moist mixtures of N 2 and O 2 . SO 2 was oxidized to H 2 SO 4 only in the moist mixtures. Oxidation of NO and reduction of NO 2 took place simultaneously and approached to a radiation-chemical stationary state in the dry N 2 -O 2 systems. NO was easily oxidized to NO 2 and finally to HNO 3 in the moist systems. Addition of NH 3 in the mixture enhanced the NO-removing reactions and suppressed the NO 2 - and HNO 3 -formations. A set of reaction mechanisms deduced is proposed. The reaction proceeds by the mechanism of such indirect effect of radiation as the energies absorbed by the main components are transferred and utilized effectively to the SO 2 - and NO sub(x)-removing reactions. (author)

Effects of ionizing radiation on plastic food packaging materials: a review. 1. Chemical and physical changes

International Nuclear Information System (INIS)

Buchalla, R.; Schuttler, C.; Bögl, K.W.

1993-01-01

Irradiation of prepackaged food causes chemical and physical changes in plastic packaging materials. The effects of ionizing radiation on these materials have been studied for almost 40 years; the respective literature is reviewed to provide the basis for a safety evaluation of plastics for use in food irradiation. Permeability of plastic films is generally not affected; deterioration of mechanical properties, that may occur with certain polymers, can usually be controlled with adequate stabilizers; and changes in infrared and UV/VIS spectra are slight at food irradiation doses. Gaseous radiolysis products include hydrogen, methane, CO 2 , CO, hydrocarbons, and for chlorine-containing polymers, hydrogen chloride. A range of volatile products, mainly hydrocarbons, alcohols, aldehydes, ketones, and carboxylic acids, has been characterized for low density polyethylene and polypropylene, other important materials, e.g., polystyrene and poly(vinyl chloride), are less well-investigated. Comparatively little is known on the effect of irradiation on multilayer structures. Radiation-induced changes are shown to depend on the chemical structure of the polymer, on the composition (additives) and processing history of the plastic, and on the irradiation conditions

Efficiency of interaction between various radiation and chemicals

International Nuclear Information System (INIS)

Kim, Jin Kyu; Song, H. S.; Kim, J. S.; Chun, K. J.; Lee, Y. K.; Lee, B. H.; Shin, H. S.; Lee, K. H.; Petin, Vladislav G.

2002-01-01

KAERI and INP (Poland) have been carried out parallel study and joint experiments on the major topics according to MOU about their cooperative project. Major experimental techniques were TSH assay, comet assay, and synergism assay. The research consisted of the following workscopes. 1) Application of TSH bioindicator for studying the biological efficiency of radiation, 2) Relative biological efficiency of californium-252 neutrons in the induction of gene and lethal mutations in TSH cells normal and enriched with boron compound, 3) Effect of pesticide on radiation-induced mutations in TSH cells, 4) Interaction of radiation with pesticide on DNA damage in human peripheral blood lymphocytes, 5) Radiomodifying effect of boron and gadolinium compounds in human peripheral blood lymphocytes, 6) Mathematical description of synergistic interactions, 7) General regularities of synergistic interactions, and 8) Determinant of synergistic interaction between radiation, heat and chemicals in cell killing. Both institutes have established wide variety of research techniques applicable to various radiation research through the cooperation. The results of research can make the role of fundamental basis for the better relationship between Korea and Poland

Chemical aspects of radiation damage processes: radiolysis

International Nuclear Information System (INIS)

Asmus, K.D.

1975-01-01

The formation of primary species and radiation chemical yields are discussed. In a section on chemical scavenging of primary species the author considers scavenging kinetics and competition reactions and gives a brief outline of some experimental methods. The radiation chemistry of aqueous solutions is discussed as an example for polar solvents. Cyclohexane is used as an example for non-polar solvents. The importance of excited states and energy transfer is considered. Reactions in the solid state are discussed and results on linear energy transfer and average ion pair formation for various kinds of radiation are surveyed. (B.R.H.)

Mechanism of Interaction between Ionizing Radiation and Chemicals

International Nuclear Information System (INIS)

Kim, Jin Kyu; Lee, B. H.; Shin, H. S.

2008-03-01

This research project has been carried out jointly with INP (Poland) to develop technologies for 'Mechanism of Interaction between ionizing radiation and chemicals . Several biological end-points were assessed in experimental organisms such as higher plants, rats, cell lines and yeast cells to establish proper bioassay techniques. The Tradescantia somatic cell mutation assay was carried out, and immunohistochemistry and hormone assays were done in Fisher 344 rats and cell lines to analyse the combined effect of ionizing radiation with mercury chloride. Using the common regularities of combined actions of two factors, a theoretical model was established, and applied to the thermo radiation action and synergism between two chemicals, as well. The model approach made it possible to predict the condition under which the maximum synergism could be attained. The research results were published in high standard journals and presented in the scientific conferences to verify KAERI's current technology level. The experience of collaboration can be used as a fundamental tool for multinational collaboration, and make the role of improving relationship between Korea and Poland

Mechanism of Interaction between Ionizing Radiation and Chemicals

Energy Technology Data Exchange (ETDEWEB)

Kim, Jin Kyu; Lee, B H; Shin, H S [and others

2008-03-15

This research project has been carried out jointly with INP (Poland) to develop technologies for 'Mechanism of Interaction between ionizing radiation and chemicals{sup .} Several biological end-points were assessed in experimental organisms such as higher plants, rats, cell lines and yeast cells to establish proper bioassay techniques. The Tradescantia somatic cell mutation assay was carried out, and immunohistochemistry and hormone assays were done in Fisher 344 rats and cell lines to analyse the combined effect of ionizing radiation with mercury chloride. Using the common regularities of combined actions of two factors, a theoretical model was established, and applied to the thermo radiation action and synergism between two chemicals, as well. The model approach made it possible to predict the condition under which the maximum synergism could be attained. The research results were published in high standard journals and presented in the scientific conferences to verify KAERI's current technology level. The experience of collaboration can be used as a fundamental tool for multinational collaboration, and make the role of improving relationship between Korea and Poland.

Mechanism of Interaction between Ionizing Radiation and Chemicals

Energy Technology Data Exchange (ETDEWEB)

Kim, Jin Kyu; Lee, B. H.; Shin, H. S. (and others)

2008-03-15

This research project has been carried out jointly with INP (Poland) to develop technologies for 'Mechanism of Interaction between ionizing radiation and chemicals{sup .} Several biological end-points were assessed in experimental organisms such as higher plants, rats, cell lines and yeast cells to establish proper bioassay techniques. The Tradescantia somatic cell mutation assay was carried out, and immunohistochemistry and hormone assays were done in Fisher 344 rats and cell lines to analyse the combined effect of ionizing radiation with mercury chloride. Using the common regularities of combined actions of two factors, a theoretical model was established, and applied to the thermo radiation action and synergism between two chemicals, as well. The model approach made it possible to predict the condition under which the maximum synergism could be attained. The research results were published in high standard journals and presented in the scientific conferences to verify KAERI's current technology level. The experience of collaboration can be used as a fundamental tool for multinational collaboration, and make the role of improving relationship between Korea and Poland.

Radiation effects in gases

International Nuclear Information System (INIS)

Leonhardt, J.W.

1985-01-01

Problems in the studies of radiation effects in gases are discussed. By means of ionization- excitation- and electron-capture yields various applications are characterized: ionization detectors, X-ray detectors, radionuclide battery, and radiation-induced chemical gas-phase reactions. Some new results of basic research in respect to the SO 2 oxidation are discussed. (author)

Synchrotron radiation facilities for chemical applications

International Nuclear Information System (INIS)

Hatano, Yoshihiko

1995-01-01

Synchrotron radiation (SR) research is of great importance in understanding radiation chemistry, physics, and biology. It is also clearly recognized in the international chemical community that chemical applications of SR are greatly advanced and divided into 1) Molecular Spectroscopy and Dynamics Studies-Gases, Surfaces, and Condensed Matter- , 2) Radiation Chemistry and Photochemistry, 3) X-ray Structural and XAFS Studies-Crystals, Surfaces, and Liquids- , 4) Analytical Chemistry, and 5) Synthesis or R and D of New Materials. In this paper, a survey is given of recent advances in the application of SR to the chemistry of excitation and ionization of molecules, i.e., SR chemistry, in the wavelength region between near-ultraviolet and hard X-rays. The topics will be chosen from those obtained at some leading SR facilities. (J.P.N.)

Transgenerational effects of radiation and chemicals in mice and humans

International Nuclear Information System (INIS)

Nomura, Taisei

2006-01-01

Parental exposure of mice to radiation and chemicals causes a variety of adverse effects (e.g., tumors, congenital malformations and embryonic deaths) in the progeny and the tumor-susceptibility phenotype is transmissible beyond the first post-radiation generation. The induced rates of tumors were 100-fold higher than those known for mouse specific locus mutations. There were clear strain differences in the types of naturally-occurring and induced tumors and most of the latter were malignant. Another important finding was that germ-line exposure elicited very weak tumorigenic responses, but caused persistent hypersensitivity in the offspring for the subsequent development of cancer by the postnatal environment. Activations of oncogenes, ras, mos, abl, etc. and mutations in tumor suppressor genes such as p53 were also detected in specific tumors in cancer-prone descendants. However, the majority of tumors observed in the progeny were those commonly observed in the strains that were used and oncogene activations were rarely observed in these tumors. It can be hypothesized that genetic instability modifies tumor occurrence in a transgenerational manner, but so far no links could be established between chromosomal and molecular changes and transmissible tumor risks. Our data are consistent with the hypothesis that cumulative changes in many normal but cancer-related genes affecting immunological, biochemical and physiological functions may slightly elevate the incidence of tumors or fasten the tumor development. This hypothesis is supported by our GeneChip analyses which showed suppression and/or over-expression of many such genes in the offspring of mice exposed to radiation. In humans, a higher risk of leukemia and birth defects has been reported in the children of fathers who had been exposed to radionuclides in the nuclear reprocessing plants and to diagnostic radiation. These findings have not been supported in the children of atomic bomb survivors in Hiroshima

State and tendencies of chemical protection against ionizing radiation

International Nuclear Information System (INIS)

Siegel, G.; Tapp, E.; Haehn, J.; Hannig, H.; Dlaske, R.; Martinek, K.

1977-01-01

Papers published in 1976 in the field of chemical protection against ionizing radiation are reviewed. Protection studies in vitro and in vivo, the biochemical, pharmacological and toxic effects, the mechanisms of protection of radioprotective agents and the trends in this field of research are described. (author)

State and tendencies of chemical protection against ionizing radiation

International Nuclear Information System (INIS)

Siegel, G.; Tapp, E.; Haehn, J.; Hannig, H.; Dlaske, R.

1976-03-01

Papers published in 1974 in the field of chemical protection against ionizing radiation are reviewed. Protection studies in vitro and in vivo, the biochemical, pharmacological and toxic effects, the mechanisms of protection of radioprotective agents and the trends in this field of research are described. (author)

State and tendencies of chemical protection against ionizing radiation

International Nuclear Information System (INIS)

Siegel, G.; Tapp, E.; Haehn, J.; Hannig, H.; Dlaske, R.; Martinek, K.

1977-01-01

Papers published in 1975 in the field of chemical protection against ionizing radiation are reviewed. Protection studies in vitro and in vivo, the biochemical, pharmacological and toxic effects, the mechanisms of protection of radioprotective agents and the trends in this field of research are described. (author)

Effects of ionizing radiation in the physico-chemical characteristics of red wine Cabernet Sauvignon

International Nuclear Information System (INIS)

Silva, Fellipe Souza da; Leiras, Anderson; Wagner, Walsan

2014-01-01

The oenology in the current days is increasingly aimed obtain improvements on wine quality produced without there the deterioration of characteristics of the same, using new technologies for such order. The objective of present work will be the application of the radiation ionizing in wines Cabernet Sauvignon, with the interest of analyzing its effects on physic-chemical characteristics of this wines, such as quality, aging and etc. Were analyzed the following strands: degree alcoholic; dry extract; density and absorbance with spectrometer (420, 520 and 620 nm). (author)

The ionising radiation effect on physico-chemical properties of organosilicon oils

International Nuclear Information System (INIS)

Krasnopyorova, A.P.

1998-01-01

The physico-chemical characteristics of organosilicon oils, as dielectric constant, viscosity, and refractive index, have been measured before and after the gamma irradiation with the doses of 10 3 to 10 6 Gray. The organosilicons studied were PMS-1, PMS-5, PMS-VV, and PMFS. All the measurements were performed with 60 Co in open test tubes as a source of gamma radiation. The structure modifications in oil molecules depending on irradiation dose have been studied with IR spectrometry. When comparing the main characteristics of the studied organosilicons before and after the irradiation one may arrange them into the following sequence with the increasing of their resistance to the gamma radiation: PMS-VV 6 GRay. For the liquids PMS-1 and PMS-VV it is found that the increasing of their viscosity with the dose absorbed obeys exponential law: ν ν 0 exp (K γ .D), where ν 0 and ν are the viscosities of the sample before and after the irradiation, respectively; D is the absorbed radiation dose; K γ is the radiation damage factor. (author)

Radiation-chemical hardening of phenol-formaldehyde oligomers

International Nuclear Information System (INIS)

Shlapatskaya, V.V.; Omel'chenko, S.I.

1978-01-01

Radiation-chemical hardening of phenol formaldehyde oligomers of the resol type has been studied in the presence of furfural and diallylphthalate diluents. The samples have been hardened on an electron accelerator at an electron energy of 1.0-1.1 MeV and a dose rate of 2-3 Mrad/s. The kinetics of hardening has been studied on the yield of gel fraction within the range of absorbed doses from 7 to 400 Mrad. Radiation-chemical hardening of the studied compositions is activated with sensitizers, namely, amines, metal chlorides, and heterocyclic derivatives of metals. Furfural and diallylphthalate compositions are suitable for forming glass-fibre plastic items by the wet method and coatings under the action of ionizing radiations

State and tendencies of chemical protection against ionizing radiation

International Nuclear Information System (INIS)

Siegel, G.; Tapp, E.; Hannig, H.; Dlaske, R.; Haehn, J.; Martinek, K.

1980-01-01

Papers published in 1978 in the field of chemical protection against ionizing radiation are reviewed. Protection studies in in-vivo and model systems, the biochemical, pharmacological and toxic effects, and modes of action of radioprotective agents are described and the trends in this field of research appreciated. (author)

Gamma radiation effects on some nutritional and physico-chemical characteristics of stored beans (Phaseolus vulgaris L.)

International Nuclear Information System (INIS)

Mancini Filho, J.

1990-01-01

The radiation effects on physico-chemical and nutritional characteristics of three Brazilian varieties of beans (Phaseolus vulgaris, L.) - Catu, Rajado and Carioca -were studied. The analytical parameters were obtained by the determination of soaking and cooking times, biological value in rats, protein electrophoretic profile, reductors sugars, oligosaccharides, fiber and fatty acids content. Also, amyloglucosidase, phytohemagglutinins, α-amylase and tryptic inhibitors activities were analysed. It was observed the gamma radiation until determined doses promotes changes on those parameters subsequently reducing substantially the cooking time without modification of the biological value of the proteins. This alteration was particularly noticed in the hard-to-cook beans. (author)

Effects of the Mt. Pinatubo eruption on the radiative and chemical processes in the troposphere and stratosphere

International Nuclear Information System (INIS)

Kinnison, D.E.; Grant, K.E.; Connell, P.S.; Wuebbles, D.J.

1992-01-01

The LLNL 2-D zonally averaged chemical-radiative transport model of the global atmosphere was used to study the effects of the June 15, 1991 eruption of the Mt. Pinatubo volcano on stratospheric processes. SAGE-11 time-dependent aerosol surface area density and optical extinction data were used as input into the model. By the winter solstice, 1991, a maximum change in column ozone was observed in the equatorial region of -2% (with heterogeneous chemical reactions on sulfuric acid aerosols) and -5.5% (including heterogeneous reactions plus radiative feedbacks). Maximum local ozone decreases of 12% were derived in the equatorial region, at 25 km, for winter solstice 1991. Column NO 2 peaked (-14%) at 30 S in October 1991. Local concentrations of NO x , Cl x , and HO x , in the lower stratosphere, were calculated to have changed between 30 S and 30 N by -40%, +80%, and +60% respectively

Influence of chemical inhibitors on cell recovery after exposure to different LET radiation

Energy Technology Data Exchange (ETDEWEB)

Evstratova, Ekaterina S.; Petin, Vladislav G. [Medical Radiological Research Center, Obninsk (Russian Federation); Kim, Jin Kyu; KIm, Jin Hong [Korea Atomic Energy Research Institute, Jeongeup (Korea, Republic of)

2016-12-15

Chemical radiosensitizers are often used to increase cell radiosensitivity. It is known that the ability of chemical drugs to increase cell radiosensitivity is related with inhibition of cell recovery from damage induced by ionizing radiation. However, there are little comparative investigations of cell sensitivity modification after exposure to radiation with high linear energy transfer (LET). Therefore, we studied the anticancer drugs cisplatin and endoxan and their impact on the ability of yeast cells to recover after cell exposure to radiations with different LET. The ability of cell recovery from radiation damage was less effective after exposure to high-LET radiation, when cells were irradiated without drug, with the increase in cisplatin concentration resulting in the disappearance of this difference. The increase of cisplatin concentration results in progressive increase in the fraction of irreversible damage independently of radiation quality.

Influence of chemical inhibitors on cell recovery after exposure to different LET radiation

International Nuclear Information System (INIS)

Evstratova, Ekaterina S.; Petin, Vladislav G.; Kim, Jin Kyu; KIm, Jin Hong

2016-01-01

Chemical radiosensitizers are often used to increase cell radiosensitivity. It is known that the ability of chemical drugs to increase cell radiosensitivity is related with inhibition of cell recovery from damage induced by ionizing radiation. However, there are little comparative investigations of cell sensitivity modification after exposure to radiation with high linear energy transfer (LET). Therefore, we studied the anticancer drugs cisplatin and endoxan and their impact on the ability of yeast cells to recover after cell exposure to radiations with different LET. The ability of cell recovery from radiation damage was less effective after exposure to high-LET radiation, when cells were irradiated without drug, with the increase in cisplatin concentration resulting in the disappearance of this difference. The increase of cisplatin concentration results in progressive increase in the fraction of irreversible damage independently of radiation quality.

State and tendencies of chemical protection against ionizing radiation

International Nuclear Information System (INIS)

Siegel, G.; Tapp, E.; Hannig, H.; Dlaske, R.; Papendieck, W.; Martinek, K.; Haehn, J.

1982-01-01

Papers published in 1979 and 1980 in the field of chemical protection against ionizing radiation are reviewed. Protection studies in in-vivo and model systems, the biochemical, pharmacological and toxic effects, and modes of action of radioprotective agents are described and the trends in this field of research estimated. (author)

Radiation effects in ice: New results

International Nuclear Information System (INIS)

Baragiola, R.A.; Fama, M.; Loeffler, M.J.; Raut, U.; Shi, J.

2008-01-01

Studies of radiation effects in ice are motivated by intrinsic interest and by applications in astronomy. Here we report on new and recent results on radiation effects induced by energetic ions in ice: amorphization of crystalline ice, compaction of microporous amorphous ice, electrostatic charging and dielectric breakdown and correlated structural/chemical changes in the irradiation of water-ammonia ices

Radiation chemical effects of X-rays on liquids

International Nuclear Information System (INIS)

Holroyd, R.A.; Preses, J.M.

1998-01-01

This review describes some of the chemical changes induced by photoelectrons which are released in liquids when X-rays are absorbed. Both experimental studies and theory are discussed. In part 1, the basic processes occurring upon absorption of X-rays are described. Parts 2 and 3 deal with hydrocarbon liquids; in part 2 the ion yields, including effects at K-edges, and in part 3, the yields of excited states. Part 4 discusses chemical effects of X-rays in aqueous solutions. The authors end with a summary of future needs and directions

Statistical trend of radiation chemical studies

International Nuclear Information System (INIS)

Yoshida, Hiroshi

1980-01-01

In the field of radiation chemistry, over 1,000 reports are published year after year. Attempt has been made to review the trends in this field for more than five years, by looking through the lists of papers statistically. As for the period from 1974 to 1978, Annual Cumulation with Keyword and Author Indexes in the Biweekly List of Papers on Radiation Chemistry was referred to. For 1979, because of the unavailability of the Cumulation, Chemical Abstracts Search by Japan Information Center of Science and Technology was referred to. The contents are as follows: how far radiation chemistry is studied, what the trends of radiation chemistry is in recent years, who contributes to the advance of radiation chemistry, and where, the trend radiation chemistry takes in 1979. (J.P.N.)

The relation between repair of DNA and radiation and chemical mutagenesis in Saccharomyces cerevisiae

International Nuclear Information System (INIS)

Prakash, L.

1976-01-01

The effect of various genes involved in DNA repair functions on radiation and chemical mutagenesis in Escherichia coli is discussed and compared to similar studies done in yeast. Results of the effect of various genes conferring radiation-sensitivty on mutation induction in yeast are presented and related to current ideas of mutagenesis

Chemical and kinetic equilibrations via radiative parton transport

International Nuclear Information System (INIS)

Zhang Bin; Wortman, Warner A

2011-01-01

A hot and dense partonic system can be produced in the early stage of a relativistic heavy ion collision. How it equilibrates is important for the extraction of Quark-Gluon Plasma properties. We study the chemical and kinetic equilibrations of the Quark-Gluon Plasma using a radiative transport model. Thermal and Color-Glass-Condensate motivated initial conditions are used. We observe that screened parton interactions always lead to partial pressure isotropization. Different initial pressure anisotropies result in the same asymptotic evolution. Comparison of evolutions with and without radiative processes shows that chemical equilibration interacts with kinetic equilibration and radiative processes can contribute significantly to pressure isotropization.

Radiobiology: Biologic effects of ionizing radiations

International Nuclear Information System (INIS)

Held, K.D.

1987-01-01

The biologic effects after exposure to ionizing radiation, such as cell death or tissue injury, result from a chain of complex physical, chemical, metabolic, and histologic events. The time scale of these radiation actions spans many orders of magnitude. The physical absorption of ionizing radiation occurs in about 10 -18 s, while late carcinogenic and genetic effects are expressed years or even generations later. Collectively, these effects form the science of radiobiology. Many of the concepts discussed in this chapter have been developed through the study of effects generated in tissues by external radiation sources, but they apply generally and often specifically to internally distributed radiopharmaceuticals which form the central topic of this book

Correlation and regression analyses of genetic effects for different types of cells in mammals under radiation and chemical treatment

International Nuclear Information System (INIS)

Slutskaya, N.G.; Mosseh, I.B.

2006-01-01

Data about genetic mutations under radiation and chemical treatment for different types of cells have been analyzed with correlation and regression analyses. Linear correlation between different genetic effects in sex cells and somatic cells have found. The results may be extrapolated on sex cells of human and mammals. (authors)

Cooperative biological effects between ionizing radiation and other physical and chemical agents.

Science.gov (United States)

Manti, Lorenzo; D'Arco, Annalisa

2010-01-01

Exposure to ionizing radiation (IR), at environmentally and therapeutically relevant doses or as a result of diagnostics or accidents, causes cyto- and genotoxic damage. However, exposure to IR alone is a rare event as it occurs in spatial and temporal combination with several physico-chemical agents. Some of these are of known noxiousness, as is the case with chemical compounds at high dose, hence additive/synergistic effects can be expected or have been demonstrated. Conversely, the cellular toxicity of other agents, such as non-ionizing electromagnetic fields (EMFs), is only presumed and their short- and long-term cooperation on IR-induced damage remains undetermined. In this review, we shall examine evidence in support of the interplay between spatially and/or temporally related environmentally relevant stressors. In vitro or animal-based studies as well as epidemiological surveys have generally examined the combined action of no more than a couple of known or potentially DNA-damaging agents. Moreover, most existing research mainly focused on short-term effects of combined exposures. Hence, it is important that quantitative research addresses the issue of the possible cooperation between chronic exposure to environmental trace contaminants and exposure to EMFs, examining not only the modulation of damage acutely induced by IR but also long-term genome stability. 2010 Elsevier B.V. All rights reserved.

Investigation into effects of ionizing radiations on physical-chemical properties of bulgarian sorts of peaches and grapes

International Nuclear Information System (INIS)

Dimitrov, D.; Kalinov, V.; Nikolova, M.; Pavlova, E.

1974-01-01

The aim of this study was to ascertain the degree and direction of those changes in physicochemical characteristics of irradiated peaches and grapes which determine their quality after irradiation and during storage. The following main conclusions are made: irradiation with doses of 200 to 300 krad does not cause significant alterations in the chemical composition and physicochemical characteristics of peaches and grapes; irradiation has a direct effect on the consistancy of peaches and grapes, leading to their softening which is proportional to the radiation dose used; radiation treatment is advisable in the case of peaches and grapes in tended for short-term rather than long-term storage at low temperatures

Comparative biological hazards of chemical pollutants and radiation

International Nuclear Information System (INIS)

Mukherjee, R.N.

1978-01-01

Chemical pollutants from conventional energy and industrial sources released to the environment presumably pose a hazard to man's health and environmental resources. Insufficient knowledge of their detailed mechanisms of interaction with the biological systems seems to provide the greatest drawback in current attempts for realistic assessment of the health risks of chemical pollutants in the short and long terms. Nevertheless, their detrimental health consequences are becoming more and more apparent as a result of recent epidemiological surveys of workers in conventional energy installations and of the chronically exposed general public. So far nuclear power has succeeded in achieving a remarkable health safety record. In view of its projected expansion, research on biological effects of low-level radiation and radionuclides should continue to re-evaluate the health safety consequences. However, a projection from past experiences together with continued efforts to improvements of health safety aspects seem to justify an expectation that the proposed expansions in the nuclear power programme should not have an unfavourable impact on the environment. The potential hazards and challenges from the associated radiation in man's environment have proved manageable. More attention now needs to be paid urgently to safeguard human health and environment against the chemical pollutants

Comparative biological hazards of chemical pollutants and radiation

Energy Technology Data Exchange (ETDEWEB)

Mukherjee, R N [International Atomic Energy Agency, Vienna (Austria). Div. of Life Sciences

1978-06-01

Chemical pollutants from conventional energy and industrial sources released to the environment presumably pose a hazard to man's health and environmental resources. Insufficient knowledge of their detailed mechanisms of interaction with the biological systems seems to provide the greatest drawback in current attempts for realistic assessment of the health risks of chemical pollutants in the short and long terms. Nevertheless, their detrimental health consequences are becoming more and more apparent as a result of recent epidemiological surveys of workers in conventional energy installations and of the chronically exposed general public. So far nuclear power has succeeded in achieving a remarkable health safety record. In view of its projected expansion, research on biological effects of low-level radiation and radionuclides should continue to re-evaluate the health safety consequences. However, a projection from past experiences together with continued efforts to improvements of health safety aspects seem to justify an expectation that the proposed expansions in the nuclear power programme should not have an unfavourable impact on the environment. The potential hazards and challenges from the associated radiation in man's environment have proved manageable. More attention now needs to be paid urgently to safeguard human health and environment against the chemical pollutants.

Test plan for Digface Chemical and Radiation Assay System

International Nuclear Information System (INIS)

Akers, D.W.

1993-07-01

The Digface Chemical and Radiation Assay System (CRAS) Project will develop a sensor using Prompt Gamma Neutron Activation Analysis (PGNAA) that can detect the present of hazardous chemicals and radioactive materials. The CRAS is being designed for in situ assay of closed drums and contaminated soils for gamma-ray emitting radionuclides and hazardous elements. The CRAS is based upon the use of 252 Cf PGNAA with a germanium gamma-ray spectrometer as the analyzer. Tasks being performed include determining detection limits for a number of hazardous chemicals and assessing matrix and transmission effects through soil. Initial analyses suggest that the technique is applicable to a number of hazardous materials such as trichloroethane and carbon tetrachloride

Chemical and radiation injuries

International Nuclear Information System (INIS)

Hugo, M.J.

1981-01-01

The paper is a discussion of radiation injuries and the treatment thereof. Radiation injuries are mainly caused as a result of nuclear leaks or nuclear bomb explosions. Such an explosion is usually accompanied by a light flash, noise, heat radiation and nuclear radiation which can all caurse various types of injuries. The general effect of radioactive radiation is discussed. The seriousness of the situation where the whole body was exposed to nuclear radiation, depends on the total radiation dose received and varies from person to person. The progress of radiation sickness is described. Mention is also made of long term radiation effects. The emergency treatment of the injured before specialised aid is available, is discussed. The primary aim of treatment is to save life and to prevent further injuries and complications. Injured people must be removed as far as possible from the point of maximum radiation. Attention must also be given to decontamination

Effects of radiation and chemicals on SV40 oncogenesis. Final progress report

International Nuclear Information System (INIS)

Coggin, J.H. Jr.

1982-05-01

This project is directed toward developing rapid, quantitative methods and immunologic markers which will permit the early detection of newly forming tumors induced or enhanced by x-irradiation, chemical carcinogens, viruses or combinations of the three. The projects under study in our ongoing collaborative program seek to develop the detailed understanding and precise methodology required for the early detection of embryonic antigens in transformed cells induced by the co-carcinogenic effects of viruses and low-level radiation. A new technique for assaying the earliest transformed cells appearing in a carcinogen treated population affords a unique tool for this study. Present plans involve efforts to purify embryonic determinants from fetal and transformed cells of hamsters and mice in order to define their role in the transformation process and in tumor development

Radiation protection in the pharmaceutical-chemical industry

International Nuclear Information System (INIS)

Griesser, R.

1992-01-01

Some aspects of the use of ionizing radiation in research in the pharmaceutical and chemical industries will be discussed, the emphasis being placed on the handling of open radioactive materials in research laboratories. The compliance with official regulations and the preparation of company internal radiation protection regulations are described. 1 tab., 9 refs

Gamma radiation effects on physico-chemical parameters of apple fruit during commercial post-harvest preservation

International Nuclear Information System (INIS)

Mostafavi, Hossein Ahari; Mirmajlessi, Seyed Mahyar; Mirjalili, Seyed Mohammad; Fathollahi, Hadi; Askari, Hadi

2012-01-01

The physico-chemical parameters (including moisture, total soluble solids, antioxidant activity, phenolic content and firmness) of cv. Red Delicious apple subjected to γ radiation were evaluated for their ability to avoid the post-harvest blue mold caused by Penicillium expansum during cold storage. Freshly harvested apples were inoculated with P. expansum. Treated fruits were irradiated at doses of 0, 300, 600, 900 and 1200 Gy and stored at 1 °C. Apples were evaluated at three month intervals. The results showed that there was a clear link between phenolic content and antioxidant activity, so that dose range of 900 Gy and higher significantly decreased phenolic content and antioxidant activity. The moisture percent of stored apples was more responsive to irradiation (at doses of 900–1200 Gy) than storage time and pathogen. Lesion diameter of pathogen-treated non-irradiated apples was significantly increased after three months. This means that storage at low temperature is not enough to avoid blue mold growth. As dose and storage time increased firmness decreased; also pathogen accelerated softening of stored apples. This study showed conclusively that low irradiation doses (300 and 600 Gy) combined with cold storage is a way to minimize apple quality losses during nine month storage period. - Highlights: ► A suitable method to reduce apple quality losses during nine month storage period. ► Effects of γ radiation and cold storage on physico-chemical parameters of the apple. ► Potential dual benefit of low irradiation dose combined with cold storage. ► Radiation dose determination for Penicillium expansum control.

Chemical decontamination solutions: Effects on PWR equipment

International Nuclear Information System (INIS)

Pezze, C.M.; Colvin, E.R.; Aspden, R.G.

1992-01-01

A critical objective for the nuclear industry is the reduction of personnel exposure to radiation. Reductions have been achieved through industry's radiation management programs including training and radiation awareness concepts. Increased plant maintenance and higher radiation fields at many sites continue to raise concerns. To alleviate the radiation exposure problem, the sources of radiation which contribute to personnel exposure must be removed from the plant. A feasible was of significantly reducing these sources from a Pressurized Water Reactor (PWR) is to chemically decontaminate the entire reactor coolant system (RCS). A program was conducted to determine the technical acceptability of using certain dilute chemical solvent processes for full RCS chemical decontamination. The two processes evaluated were CAN-DEREM and LOMI. The purpose of the program was to define and complete a systematic evaluation of the major issues that need to be addressed for the successful decontamination of the entire RCS and affected portions of the auxiliary systems of a four-loop PWR system. A test program was designed to evaluate the corrosion effects of the two decontamination processes under expected plant conditions. Materials and sample configurations dictated by generic PWR components were evaluated. The testing also included many standard corrosion coupons. The test data were then used to assess the impact of chemical decontamination on the physical condition and operability of the components, equipment and mechanical systems that make up the RCS. An overview of the test program, sample configurations, data and engineering evaluations is presented. The data demonstrate that through detailed engineering evaluations of corrosion data and equipment function, the impact of full RCS chemical decontamination on plant equipment is established

Radiation chemical transformations of some polyarylates by γ-radiation in vacuum

International Nuclear Information System (INIS)

Lyashevich, V.V.; Korshak, V.V.; Rodeh, V.V.; Timofeeva, G.I.

1976-01-01

A study was made of ageing by radiation of F-2 and D-9 polyarylates using γ-radiation in vacuum. Their high resistance to radiation was indicated. It was found that γ-radiation on polymers caused competing reactions to take place resulting in macromolecular breakdown and structure formation, which in the end produced threedimensional network formation. The initial formation of gel fractions was preceded by the formation of branched macromolecules. The radiation resistance of polyarylates depends on the type of lateral substituent at the central carbon atom of the initial bis-phenol and increases in the presence of a fluorene ring in the lateral chain. The radiation resistance of a lactone ring is lower than that of an ether bond of the main chain. It was shown that 0-hydroxy-ketone structures were formed in the polyarylates examined as a result of regrouping due to radiation. A basic system is proposed for chemical conversion of polyarylates by radiation

Pilot-industrial plant for radiation-chemical finishing of textiles

International Nuclear Information System (INIS)

Burov, V.K.; Vanyushkin, B.M.; Voskoboev, A.E.

1976-01-01

A pilot technological radiational-chemical line for liquid-phase radiational-chemical finish of fabrics is described, which is being mounted at the Glukhov cotton group of enterprises now. It is designed primarily for the anti-microbe finish of cotton fabrics by grafting copper polyacrylate. The technological scheme is built on the principle of direct (combined) irradiation of the fabric impregnated by a monomer solution. Graft of the monomer to the fabric is performed by the radiational method. As source of radiation, an electron accelerator with the beam power of 0.4-0.7 Mev and with a biological protection has been employed. Depending on the thickness of the material irradiated and irradiation conditions, the fabric drive mechanism permits to change a number of irradiated fabric layers from 1 to 9 and by this to utilize in the most complete manner the energy of the accelerated electron beam. The nominal width of the irradiated material is 1000 m, the transportation velocity can vary in the range from 10 through 100 m/min. The radiational-chemical method of fabric finish is economical, highly productive and easily controllable

Radiation-induced mammary carcinogenesis in rodent models. What's different from chemical carcinogenesis?

International Nuclear Information System (INIS)

Imaoka, Tatsuhiko; Nishimura, Mayumi; Iizuka, Daisuke; Daino, Kazuhiro; Takabatake, Takashi; Okamoto, Mieko; Kakinuma, Shizuko; Shimada, Yoshiya

2009-01-01

Ionizing radiation is one of a few well-characterized etiologic factors of human breast cancer. Laboratory rodents serve as useful experimental models for investigating dose responses and mechanisms of cancer development. Using these models, a lot of information has been accumulated about mammary gland cancer, which can be induced by both chemical carcinogens and radiation. In this review, we first list some experimental rodent models of breast cancer induction. We then focus on several topics that are important in understanding the mechanisms and risk modification of breast cancer development, and compare radiation and chemical carcinogenesis models. We will focus on the pathology and natural history of cancer development in these models, genetic changes observed in induced cancers, indirect effects of carcinogens, and finally risk modification by reproductive factors and age at exposure to the carcinogens. In addition, we summarize the knowledge available on mammary stem/progenitor cells as a potential target of carcinogens. Comparison of chemical and radiation carcinogenesis models on these topics indicates certain similarities, but it also indicates clear differences in several important aspects, such as genetic alterations of induced cancers and modification of susceptibility by age and reproductive factors. Identification of the target cell type and relevant translational research for human risk management may be among the important issues that are addressed by radiation carcinogenesis models. (author)

Effect of electromagnetic radiation on the physico-chemical properties of minerals; Efecto de la radiacion electromagnetica en las propiedades fisicoquimicas de los minerales

Energy Technology Data Exchange (ETDEWEB)

Lopez M, A.; Delgadillo G, J. A. [Universidad Autonoma de San Luis Potosi, Instituto de Metalurgia, Doctorado Institucional de Ingenieria y Ciencia de Materiales, Av. Sierra Leona 550, 78210 San Luis Potosi (Mexico); Vega C, H. R., E-mail: alopezm6@yahoo.com.mx [Universidad Autonoma de Zacatecas, Unidad Academica de Estudios Nucleares, Cipres No. 10, Fracc. La Penuela, 98068 Zacatecas (Mexico)

2014-08-15

The electromagnetic radiation effect represented by gamma rays was investigated through; chemical analysis, X-ray diffraction (XRD), scanning electron microscopy (Sem) and magnetization when applied at a dose of 0.5704 Gy (0.5704 J/ kg) at a feed relation of 18.40 ± 1.13 mGy/ h., in different minerals; in order to characterize the impact of the same from {sup 137}Cs in the physicochemical properties of these minerals. All the irradiated samples showed chemical stability at this stage undetectable other both in the XRD study and in the images analysis obtained by Sem; and at present almost the same chemical composition as the non-irradiated samples. So the same patterns of X-ray diffraction thereof, show a tendency to slightly lower the intensity of the most representative peaks of each mineral phase, which may be due to a decrease in crystallinity or preferential crystallographic orientation in crystals. In the micrographs analysis obtained by Sem on the irradiated samples, some holes (open pores) present in the particles were observed, mainly chalcopyrite and sphalerite lesser extent, seen this fact may be due to Compton Effect, in the radiation process. In relation to the magnetization property, a variation is obtained in the saturation magnetization (Ms) for the irradiated samples containing iron and more significantly in the chalcopyrite case. Therefore, with the radiation level used; slight changes occurring in the physical properties of minerals, whereas they remained stable chemically. These small changes may represent a signal that electromagnetic radiation applied at higher doses, is a viable option for improving the mineral processing. (author)

Investigation into radiation-chemical transformations of polyamide P-54

International Nuclear Information System (INIS)

Khabarov, V.N.; Kozlov, L.L.; Panchenkov, G.M.

1981-01-01

Investigation results of alcohol-soluble polyamide P-54 radiolysis by different physicochemical methods are presented. It has been established that under the effect of γ-radiation certain processes take place in polyamide, which are connected with branching, structurization and destruction of macromolecules. Radiation-chemical yields of gaseous products during irradiation in the air and in vacuum at irradiation temperatures from 273 to 393 K are calculated. The ratio of the rates of lacing and destruction processes is found and radiation yields of the processes are determined. Under irradiation in the air at temperatures >333 K chain oxidation of P-54 takes place and the growth of pe-- roxide compounds with 8 molecules/100 eV at 298 K up to 135 mole-- cules/100 eV at irradiation temperature 373 K testifies to the fact

Indirect radiation effects related to the environmental structure of targets

International Nuclear Information System (INIS)

Frankenberg, D.

1976-01-01

It is supposed, that in biological systems there are direct as well as indirect radiation effects. Their contributions to lethal effects depend mainly on two different kinds of structures within irradiated systems: the microscopic energy deposition patterns of radiation and the environmental structures of targets. The approach to determine these contributions of the lethal action of ionizing radiation in yeast cells was, to use chemical compounds, which specifically change the radical spectrum of water radiolysis. The efficiency of such chemical compounds in scavenging specifically water radicals was tested in aqueous solutions of thymine molecules, in which indirect radiation effects occur exclusively. The main result is, that the OH'-radical is by far the most effective radical to destroy thymine molecules. The relative contributions of direct and indirect radiation effects to lethal actions of ionizing radiation was investigated in yeast cells. The radical spectrum of water radiolysis was changed by bubbling the cell suspensions with different gases. The main result is, that there are no lethal radiation effects du to the action of water radicals

Comparison between cytogenetic damage induced in human lymphocytes by environmental chemicals or radiation

Energy Technology Data Exchange (ETDEWEB)

Cebulska-Wasilewska, A. [Institute of Nuclear Physics, Cracow (Poland)

1997-12-31

Author compared cytogenetic effects of chemicals (benzene and the member at benzene related compounds) and ionizing radiation on the human lymphocytes. Levels of various types of cytogenetic damage observed among people from petroleum plants workers groups are similar to the levels of damages detected in the blood of people suspected of the accidental exposure to a radiation source

Comparison between cytogenetic damage induced in human lymphocytes by environmental chemicals or radiation

International Nuclear Information System (INIS)

Cebulska-Wasilewska, A.

1997-01-01

Author compared cytogenetic effects of chemicals (benzene and the member at benzene related compounds) and ionizing radiation on the human lymphocytes. Levels of various types of cytogenetic damage observed among people from petroleum plants workers groups are similar to the levels of damages detected in the blood of people suspected of the accidental exposure to a radiation source

Effect of ionizing radiation on starch and cellulose

International Nuclear Information System (INIS)

Klenha, J.; Bockova, J.

1973-09-01

The investigation is reported of the effects of ionizing radiation both on macromolecular systems generally and on polysaccharides, starch and cellulose. Attention is focused on changes in the physical and physico-chemical properties of starch and cellulose, such as starch swelling, gelation, viscosity, solubility, reaction with iodine, UV, IR and ESR spectra, chemical changes resulting from radiolysis and from the effect of amylases on irradiated starch, changes in cellulose fibre strength, water absorption, stain affinity, and also the degradation of cellulose by radiation and the effect of cellulases on irradiated cellulose. Practical applications of the findings concerning cellulose degradation are discussed. (author)

Time-resolved studies of direct effects of radiation on DNA

International Nuclear Information System (INIS)

Fielden, E.M.; O'Neill, P.; Al-Kazwini, A.

1987-01-01

The biological changes induced by ionising radiation are a consequence of radiation-induced chemical events taking place at times <1s. These events are strongly influenced by the presence of chemical modifiers. Since DNA is a principle target for radiation-induced cell killing, DNA-free radicals are generated by direct ionisation of DNA moieties (direct effect) and by reaction with hydroxyl radicals formed by radiolysis of the water which is in the vicinity of the DNA (indirect effect). In order to study the 'direct' effects of radiation on DNA the following model approaches are discussed:- 1) Use of the technique of pulse radiolysis to investigate in aqueous solution the interactions of deoxynucleosides with SO/sub 4//sup .-/ whereby one-electron oxidised species of the bases are generated; and 2) time resolved, radiation-induced changes to solid DNA and related macromolecules (e.g. radiation-induced luminescence) in order to obtain an understanding of charge/energy migration as a result of ionisation of DNA. The influence of chemical modifiers and of environment is discussed in terms of the properties of the radiation-induced species produced. Since the properties of base radicals produced by SO/sub 4//sup .-/ are similar to those of the base OH-adducts oxidising properties, potential similarities between the 'direct' and 'indirect' effects of radiation are presented

Biological effects of radiation and estimation of risk to radiation workers

International Nuclear Information System (INIS)

Murthy, M.S.S.

1987-01-01

The biological effects of radiation have three stages: physical, chemical and biological. A precise mathematical description of biological effects and of one-to-one correspondence between the initial energy absorption and final effect has not been possible, because several factors are involved in biological effects and their manifestation period varies from less than one second to several years. The mechanism of biological radiation effects is outlined. The two groups of these effects are (1) immediate and (2) delayed. The main aim of radiation protection programme is to eliminate the risk of non-stochastic effects to an acceptable level. The mean annual dose for 30,000 radiation workers in India is 2.7 m Sv. Estimated risk of fatal cancer from this dose is about 50 cases of cancer per year per million workers which is well below the ICRP standard for safe occupation stipulated at fatality rate less than or equal to 100 per year per milion workers. When compared with risk in other occupations, the risk to radiation workers is much less. (M.G.B.)

Radiation effects on Fischer-Tropsch syntheses

International Nuclear Information System (INIS)

Hatada, M.; Matsuda, K.

1977-01-01

Radiation effects on Fischer-Tropsch synthesis has been examined using high dose rate electron beams and Fe-Cu-diatomaceous earth catalyst. Yields of saturated hydrocarbons were found to increase by irradiation, but the yields of these compounds were decreased by raising reaction temperature without irradiation, suggesting the presence of radiation chemical process in catalytic reactions. (author)

Biological effects of nuclear radiation

International Nuclear Information System (INIS)

Hotz, G.

1975-01-01

After a brief survey about the main radiobiological effects caused by ionizing radiation, human symptoms after irradiation and incorporation are shown. The special radiotoxic effect of radionuclides which are chemically associated with metabolism-specific elements such as calcium and potassium is shown and methods of treatment are indicated. (ORU) [de

Radiation-chemical disinfection of dissolved impurities and environmental protection

International Nuclear Information System (INIS)

Petrukhin, N.V.; Putilov, A.V.

1986-01-01

Radiation-chemical neutralization of dissolved toxic impurities formed in the production processes of different materials, while modern plants being in use, is considered. For the first time the processes of deep industrial waste detoxication and due to this peculiarities of practically thorough neutralization of dissolved toxic impurities are considered. Attention is paid to devices and economic factors of neutralization of dissolved toxic impurities. The role of radiation-chemical detoxication for environment protection is considered

Combined effects of a chemical mutagen and radiation sterilized diet in mutagenicity and reproduction studies in the same mouse

International Nuclear Information System (INIS)

Renner, H.W.

1975-01-01

The possible intensification of the mutagenic effect of cyclophosphamide (Endoxan) by the feeding of a radiation-sterilized diet (dose, 4.5 Mrad) was studied in 2000 NMRI/Han mice. In a dominant lethal test, males were pretreated with 100 mg Endoxan/kg body weight. The greatest sensitivity towards Endoxan was observed during the late-spermatid stage. No significant differences were detected between the control group (Endoxan plus non-irradiated diet) and the experimental group (Endoxan plus radiation-sterilized diet). In this test, radiation-sterilized feed showed no co-mutagenic effect when combined with Endoxan treatment. In a reproduction study of 7 months duration (continuous mating without lactation periods), the females were treated every 2 wk with 20 mg Endoxan/kg body weight. The decline in litter size with increasing number of litters (i.e. with advancing age of the females) was more pronounced after treatment with the chemical mutagen than in the untreated group. Increases in the frequency of abortions and in premature sterility resulted from Endoxan treatment. During the entire observation period, no effects from the intake of radiation-sterilized food were detected. (author)

Effect of Radiation on Microbial Contamination Activity and Chemical Composition of Antimicrobial Herbs

International Nuclear Information System (INIS)

Leelapattranuruk, Paveena

1999-01-01

The selected herbs which are known to have antimicrobial compounds i.e. garlic (Allium sativum Linn.) bulbs, pomegranate (Punica granatum Linn.) fruit rinds, roselle (Hibiscus sabdoriffa Linn.) calyxes, and tea (Camellia sinensis Linn.) leaves were exposed to gamma and ultraviolet (UV) radiations. After being irradiated with 1, 3 and 5 kGy of ionizing radiation from a cobalt-60 source for 5, 15 and 15 minutes and with non-ionizing radiation from ultraviolet source for 30, 60 and 120 minutes, the irradiated herbs were examined for number of contaminants and specified microorganisms i.e. Staphylococcus aureus, Pseudomonas aeruginosa, Escherichia coli. Salmonella spp. and Clostridium spp, as well as antimicrobial potency and components and compared to unirradiated herbs. The results showed that unirradiated garlic was most heavily contaminated with bacteria and fungi. The specified microorganisms were not detected in either unirradiated or irradiated samples. In comparison of radiated herbs, the reduction of microorganisms in UV treated herbs was less than that in gamma ray treated ones, especially at the treatment dose of 5 kGy. There was slight reduction of microbial number in UV treated herbs as compared to the untreated herbs. Gamma treatment at 5 kGy reduced the microbe contamination more than other doses and caused complete elimination in tea. The UV and gamma treatments had no effect on antimicrobial potency of herbs except for that of garlic. The preliminary chemical analysis to examine if there was any radiolytic components in these herbs by thin layer chromatography (TLC) revealed that no such compounds were detected in any tested herbs. This study indicated that gamma irradiation treatment was one of the physical methods to decontaminate microbes in herbs

Contribution of orientational effects into radiation-chemical properties of segregated block copolymers

International Nuclear Information System (INIS)

Bol'bit, N.M.; Korneev, Yu.N.

1992-01-01

Model of radiolysis of microphase-separated block copolymers of PS with PB is proposed. According this scheme the radiation-chemical yields of paramagnetic centres and crosslinks in PB domains differ from those for the PB homopolymer by the value proportional to the fraction of ordered chain segments. This orientational small-scale order arises as a result of the deformation of chains in a domain in the direction perpendicular to the interphase

Chemical and radiation environmental risk management at the crossroads: Case studies

International Nuclear Information System (INIS)

Tran, N.; Burke, T.; Locke, P.

1999-01-01

Although many of the major environmental risk management decisions we face today require the simultaneous evaluation and control of both radiological and chemical risks, the separation of radiation and chemical risk management persists along legal, regulatory, programmatic, training and professional practice levels. In June 1998, a panel of 40 chemical and radiation risk experts met at an interactive workshop entitled 'Addressing the Similarities and Differences in Chemical and Radiation Environmental Risk Management,' in Annapolis, Maryland to discuss several perspectives on harmonizing chemical and radiation risk management approaches. At the conclusion of the meeting, workshop participants recommended that case studies of clean-up sites at which radioactive materials and hazardous chemical risks were addressed, be developed to help educate participants in the harmonization dialogue about their counterpart's issues, stimulate discussion and sharpen issues in a way that they can be resolved. Several key risk management issues that were highlighted from the discussion at the Annapolis meeting are being evaluated in the case studies. They include: decision criteria, costs and public/stakeholder input. This paper presents these key issues and the approach taken in the case studies. (author)

Hydration-annealing of chemical radiation damage in calcium nitrate

International Nuclear Information System (INIS)

Nair, S.M.K.; James, C.

1984-01-01

The effect of hydration on the annealing of chemical radiation damage in anhydrous calcium nitrate has been investigated. Rehydration of the anhydrous irradiated nitrate induces direct recovery of the damage. The rehydrated salt is susceptible to thermal annealing but the extent of annealing is small compared to that in the anhydrous salt. The direct recovery of damage on rehydration is due to enhanced lattice mobility. The recovery process is unimolecular. (author)

Health effects of ionizing radiation

International Nuclear Information System (INIS)

Pathak, B.

1989-12-01

Ionizing radiation is energy that travels through space as electromagnetic waves or a stream of fast moving particles. In the workplace, the sources of ionizing radiation are radioactive substances, nuclear power plants, x-ray machines and nuclear devices used in medicine, research and industry. Commonly encountered types of radiation are alpha particles, beta particles and gamma rays. Alpha particles have very little penetrating power and pose a risk only when the radioactive substance is deposited inside the body. Beta particles are more penetrating than alpha particles and can penetrate the outer body tissues causing damage to the skin and the eyes. Gamma rays are highly penetrating and can cause radiation damage to the whole body. The probability of radiation-induced disease depends on the accumulated amount of radiation dose. The main health effects of ionizing radiation are cancers in exposed persons and genetic disorders in the children, grandchildren and subsequent generations of the exposed parents. The fetus is highly sensitive to radiation-induced abnormalities. At high doses, radiation can cause cataracts in the eyes. There is no firm evidence that ionizing radiation causes premature aging. Radiation-induced sterility is highly unlikely for occupational doses. The data on the combined effect of ionizing radiation and other cancer-causing physical and chemical agents are inconclusive

Effects of radiation and other influences on chemical lymphomagenesis

Energy Technology Data Exchange (ETDEWEB)

Seidel, H.J.

1987-06-01

Methylnitrosourea (MNU) or butylnitrosourea (BNU) was used to induce T cell lymphomas (thymomas) in BDF/sub 1/ mice. In addition to the chemical, X-rays in various dose schedules were applied. An effect of the irradiation (shortening of the latency period) was seen with 12 x 0.25 Gy in protocols with a prolonged median induction time in the controls as a result of a dose reduction of the chemical (median induction time 27-36 weeks instead of 16-18 weeks under optimal conditions using 50 mg kg/sup -1/ of MNU). Preirradiation 2-5 weeks before 40 mg kg/sup -1/ of MNU resulted in enhanced leukaemogenesis. Also, mice with regenerating lympho-haemopoiesis after lethal irradiation and bone marrow transplantation were more sensitive to the effect of both chemicals than were the controls. Treatment with anti-thy 1.2 and with corynebacterium parvum during the latency period had no influence.

Reduction of radiation effects by chemical protector (WR-2721)

International Nuclear Information System (INIS)

Lee, C.H.; Kim, Y.K.; Yun, T.K.; Koh, J.H.

1985-01-01

As a part studies on effect of radiation, the present report was carried out to evaluate the changes of leukocytes, lymphocytes percent of leukocytes and several organs in swiss webster (NIH-GP) mice by radiation protective agents prior to γ-ray exposure. The whole body irradiation after administration of a radiation protective agents was done in dose level of 25,50,100 and 300 rads by a single exposure of γ-ray delivered from 60 Co, source tele-irradiation unit at a dose rate of 100 rad/min. Mice of each experimental group were whole body γ-irradiated in plastic cage with special producted rotating machine. The radiation protective agent was employed WR-2721 and the amounts injected intraperitoneally were 400mg/kg of body weight. The leukocytes were counted with hemocytometer. Differential count of leukocytes was done with 200 cells every smear and lymphocyte percent of leukocyte were determined in relative proportion only. All major organ were examined grossly and weighted. After fixation with formalin solution, histo-pathological preparations were made for microscopical study. (Author)

Radiation-chemical degradation of chloroform in water solutions

International Nuclear Information System (INIS)

Ahmadov, S.A; Gurbanov, M.A; Iskenderova, Z.I; Abdullaev, E.T; Ibadov, N.A.

2006-01-01

Full text: Chloroform is the major chlorine-containing compound forming at chlorination of drinking water. As our basic water resources of Kur and Araz rivers are mostly polluted along the territory of the neighbor republics their chlorination for the purpose of biological purification can result in forming of chloroform. Unfortunately, there are only poor data about containing of chloroform in drinking water in the Republic, however the particular problem is to develop new methods of drinking water purification from chloroform, taking into account the high toxicity of this compounds. Appropriate works indicate that radiation-chemical processing can mostly reduce the concentration of chloroform in drinking water. The purification degree can achieve 95-98%. This work studies the tendency of chloroform decomposition at its radiolysis processes in percentage. Taking into account the dissolvability of chloroform in water solutions it can be said that examined water solutions are homogeneous. Following advancements are studied: b Determination of radiation-chemical yield of chloroform decomposition at its various initial concentrations;Impact of adsorbed dose on pH of solutions;Formation of by-products.It is set that radiation-chemical output of chloroform decomposition is equal to 3.10-3-125 mol 100ev.

Chernobyl health effects: radiation or stress?

International Nuclear Information System (INIS)

Grinkhal', G.

1996-01-01

Consideration is given to results of wide-scale examination of human population, subjected to the effect of radiation in result of Chernobyl accident. The examined contingents consisted of liquidators, evacuated from 30-km zone, people still living in contamination territories, children of irradiated parents and children, who received large radiation doses. High levels of respiratory system diseases, digestive system diseases, cardiovascular diseases and nervous system diseases were revealed for these people. It was revealed that stress, socio-economic and chemical factors played sufficient role in disease incidence. It is shown that fair of radiation may damage more, than radiation itself

Physical, chemical, and biological properties of radiocerium relevant to radiation protection guidelines

International Nuclear Information System (INIS)

Anon.

1978-01-01

Present knowledge of the relevant physical, chemical, and biological properties of radiocerium as a basis for establishing radiation protection guidelines is summarized. The first section of the report reviews the chemical and physical properties of radiocerium relative to the biological behavior of internally-deposited cerium and other lanthanides. The second section of the report gives the sources of radiocerium in the environment and the pathways to man. The third section of the report describes the metabolic fate of cerium in several mammalian species as a basis for predicting its metabolic fate in man. The fourth section of the report considers the biomedical effects of radiocerium in light of extensive animal experimentation. The last two sections of the report describe the history of radiation protection guidelines for radiocerium and summarize data required for evaluating the adequacy of current radiation protection guidelines. Each section begins with a summary of the most important findings that follow

Double stratification effects in chemically reactive squeezed Sutterby fluid flow with thermal radiation and mixed convection

Directory of Open Access Journals (Sweden)

S. Ahmad

2018-03-01

Full Text Available A current analysis is carried out to study theoretically the mixed convection characteristics in squeezing flow of Sutterby fluid in squeezed channel. The constitutive equation of Sutterby model is utilized to characterize the rheology of squeezing phenomenon. Flow characteristics are explored with dual stratification. In flowing fluid which contains heat and mass transport, the first order chemical reaction and radiative heat flux affect the transport phenomenon. The systems of non-linear governing equations have been modulating which then solved by mean of convergent approach (Homotopy Analysis Method. The graphs are reported and illustrated for emerging parameters. Through graphical explanations, drag force, rate of heat and mass transport are conversed for different pertinent parameters. It is found that heat and mass transport rate decays with dominant double stratified parameters and chemical reaction parameter. The present two-dimensional examination is applicable in some of the engineering processes and industrial fluid mechanics. Keywords: Squeezing flow, Sutterby fluid model, Mixed convection, Double stratification, Thermal radiation, Chemical reaction

Effect of Radiation processing on sensory and chemical characteristics of broad beans (Giza,2)(Vicia Faba)

International Nuclear Information System (INIS)

Mahmoud, A.A.; El-Niely, F.G.

2002-01-01

Broad bean is the important leguminous protein consumed in egypt as a source of protein diet. The most popular way of preparing beans is the stewd form (Fool Medames). However, great losses due to insect infestation occur during storage. To combat these losses radiation processing has been used as an effective alternative of chemical fumigants to combat insect pets. The beans were irradiated at 25.5, 10 and kgy. The effects of treatments were investigated on sensory and chemical characteristics and on the solubility of broad beans protein, the amino acids content and on the nutritive value of bean protein from the view of its amino acids profile. The results of study indicate that the sensory evaluation of sewed irradiated 2.5 and 5 kGy samples revealed no significantdiffference in hardness, gumminess and acceptability. moreover, no significant changes in adhesivess, between samples irradiated at 5, 10 and 20 KGy, irradiation up to 20 KGy was found to improve the hardness of stewed broad bean which would improve the quality of broad of bean

Chemically reactive and naturally convective high speed MHD fluid flow through an oscillatory vertical porous plate with heat and radiation absorption effect

Directory of Open Access Journals (Sweden)

S.M. Arifuzzaman

2018-04-01

Full Text Available This paper concerns with the modelling of an unsteady natural convective and higher order chemically reactive magnetohydrodynamics (MHD fluid flow with the effect of heat and radiation absorption. The flow is generated through a vertical oscillating porous plate. Boundary layer approximations is carried out to establish a flow model which represents the time dependent momentum, energy and diffusion balance equations. Before being solved numerically, the governing partial differential equations (PDEs were transformed into a set of nonlinear ordinary differential equation (ODEs by using non-similar technique. A very efficient numerical approach solves the obtained nonlinear coupled ODEs so called Explicit Finite Difference Method (EFDM. An algorithm is implemented in Compaq Visual Fortran 6.6a as a solving tool. In addition, the stability and convergence analysis (SCA is examined and shown explicitly. The advantages of SCA is its optimizes the accuracy of system parameters such as Prandtl number (Pr and Schmidt number (Sc.The velocity, temperature and concentration fields in the boundary layer region are studied in detail and the outcomes are shown in graphically with the influence of various pertinent parameters such as Grashof number (Gr, modified Grashof number (Gr, magnetic parameter (M, Darcy number (Da,Prandtl number (Pr, Schmidt number (Sc, radiation (R, heat sink (Q,radiation absorption (Q1, Eckert number (Ec, Dufour number (Du,Soret number (Sr, Schmidt number (Sc, reaction index (P and chemical reaction (Kr. Furthermore, the effect of skin friction coefficient (Cf, Nusselt number (Nu and Sherwood number (Sh are also examined graphically. Keywords: MHD, Oscillating porous plate, Radiation absorption, High order chemical reaction, EFDM

Oocyte toxicity: female germ-cell loss from radiation and chemical exposures

International Nuclear Information System (INIS)

Dobson, R.L.

1984-01-01

In some mammals, female germ cells are extraordinarily sensitive to killing by exposure to ionizing radiation, especially during development. Immature oocytes, which constitute the lifetime germ-cell pool of the female, have an LD 50 in juvenile mice of only 6 rad (compared with typical LD 50 s of 100-300 rad for most other cell types studied). Essentially, the entire germ-cell supply in female squirrel monkeys is destroyed prenatally by exposure of only 0.7 rad/day. Severe but lesser destruction has been found in other species. However, evidence suggests (though not ruled out for all developmental stages) that unusually high sensitivity probably does not occur in the human female. Germ cells can also be killed by certain chemicals, and similarities exist between chemical and radiation effects. More than 75 compounds have been quantitatively studied in mice, with determination of OTI values (OTI = oocyte toxicity index = mouse LD 50 /oocyte LD 50 ) to measure the degree of preferential oocyte killing. High sensitivity in mice does not mean necessarily high sensitivity in women. Of special interest is the recent discovery that the lethal target in the extremely sensitive mouse immature oocyte is probably the plasma membrane, not DNA. Since mouse data form the main basis from which human genetic hazard (for both radiation and chemicals) is estimated, this has important implications for the determination of genetic risk in women

Natural radiation, nuclear wastes and chemical pollutants

International Nuclear Information System (INIS)

Christensen, T.; Ehdwall, H.; Stranden, E.

1990-01-01

Doses from natural radiation to the population in the Nordic Countries are summarized and man made modifications of the natural radiation environment are discussed. An account is given of the radiological consequences of energy conservation by reduced ventilation. Risks from possible future releases of radioactivity from final repositories of spent nuclear fuel are compared to the risks from present natural radioactivity in the environment. The possibilities for comparison between chemical and radiological risks are discussed. (author) 13 refs

Trans-generational radiation-induced chromosomal instability in the female enhances the action of chemical mutagens

International Nuclear Information System (INIS)

Camats, Nuria; Garcia, Francisca; Parrilla, Juan Jose; Calaf, Joaquim; Martin, Miguel; Caldes, Montserrat Garcia

2008-01-01

Genomic instability can be produced by ionising radiation, so-called radiation-induced genomic instability, and chemical mutagens. Radiation-induced genomic instability occurs in both germinal and somatic cells and also in the offspring of irradiated individuals, and it is characterised by genetic changes including chromosomal rearrangements. The majority of studies of trans-generational, radiation-induced genomic instability have been described in the male germ line, whereas the authors who have chosen the female as a model are scarce. The aim of this work is to find out the radiation-induced effects in the foetal offspring of X-ray-treated female rats and, at the same time, the possible impact of this radiation-induced genomic instability on the action of a chemical mutagen. In order to achieve both goals, the quantity and quality of chromosomal damage were analysed. In order to detect trans-generational genomic instability, a total of 4806 metaphases from foetal tissues from the foetal offspring of X-irradiated female rats (5 Gy, acute dose) were analysed. The study's results showed that there is radiation-induced genomic instability: the number of aberrant metaphases and the breaks per total metaphases studied increased and were found to be statistically significant (p ≤ 0.05), with regard to the control group. In order to identify how this trans-generational, radiation-induced chromosomal instability could influence the chromosomal behaviour of the offspring of irradiated rat females in front of a chemical agent (aphidicolin), a total of 2481 metaphases were studied. The observed results showed that there is an enhancement of the action of the chemical agent: chromosomal breaks per aberrant metaphases show significant differences (p ≤ 0.05) in the X-ray- and aphidicolin-treated group as regards the aphidicolin-treated group. In conclusion, our findings indicate that there is trans-generational, radiation-induced chromosomal instability in the foetal cells

Trans-generational radiation-induced chromosomal instability in the female enhances the action of chemical mutagens

Energy Technology Data Exchange (ETDEWEB)

Camats, Nuria [Institut de Biotecnologia i Biomedicina (IBB), Universitat Autonoma de Barcelona, 08193 Barcelona (Spain); Departament de Biologia Cel.lular, Fisiologia i Immunologia, Universitat Autonoma de Barcelona, 08193 Barcelona (Spain); Garcia, Francisca [Institut de Biotecnologia i Biomedicina (IBB), Universitat Autonoma de Barcelona, 08193 Barcelona (Spain); Parrilla, Juan Jose [Servicio de Ginecologia y Obstetricia, Hospital Universitario Virgen de la Arrixaca, 30120 El Palmar, Murcia (Spain); Calaf, Joaquim [Servei de Ginecologia i Obstetricia, Hospital Universitari de la Santa Creu i Sant Pau, 08025 Barcelona (Spain); Martin, Miguel [Departament de Pediatria, d' Obstetricia i Ginecologia i de Medicina Preventiva, Universitat Autonoma de Barcelona, 08193 Barcelona (Spain); Caldes, Montserrat Garcia [Institut de Biotecnologia i Biomedicina (IBB), Universitat Autonoma de Barcelona, 08193 Barcelona (Spain); Departament de Biologia Cel.lular, Fisiologia i Immunologia, Universitat Autonoma de Barcelona, 08193 Barcelona (Spain)], E-mail: Montserrat.Garcia.Caldes@uab.es

2008-04-02

Genomic instability can be produced by ionising radiation, so-called radiation-induced genomic instability, and chemical mutagens. Radiation-induced genomic instability occurs in both germinal and somatic cells and also in the offspring of irradiated individuals, and it is characterised by genetic changes including chromosomal rearrangements. The majority of studies of trans-generational, radiation-induced genomic instability have been described in the male germ line, whereas the authors who have chosen the female as a model are scarce. The aim of this work is to find out the radiation-induced effects in the foetal offspring of X-ray-treated female rats and, at the same time, the possible impact of this radiation-induced genomic instability on the action of a chemical mutagen. In order to achieve both goals, the quantity and quality of chromosomal damage were analysed. In order to detect trans-generational genomic instability, a total of 4806 metaphases from foetal tissues from the foetal offspring of X-irradiated female rats (5 Gy, acute dose) were analysed. The study's results showed that there is radiation-induced genomic instability: the number of aberrant metaphases and the breaks per total metaphases studied increased and were found to be statistically significant (p {<=} 0.05), with regard to the control group. In order to identify how this trans-generational, radiation-induced chromosomal instability could influence the chromosomal behaviour of the offspring of irradiated rat females in front of a chemical agent (aphidicolin), a total of 2481 metaphases were studied. The observed results showed that there is an enhancement of the action of the chemical agent: chromosomal breaks per aberrant metaphases show significant differences (p {<=} 0.05) in the X-ray- and aphidicolin-treated group as regards the aphidicolin-treated group. In conclusion, our findings indicate that there is trans-generational, radiation-induced chromosomal instability in the foetal

Biopositive Effects of Ionizing Radiation?

International Nuclear Information System (INIS)

Broda, E.

1972-01-01

This paper was written for a talk given by E. Broda in Vienna for an event organised by the chemical physical society, the Austrian biochemical society and the Austrian biophysical society in December 1972. In this paper Broda analyses the question of biopositive effects of ionizing radiation. (nowak)

BYSTANDER EFFECTS, GENOMIC INSTABILITY, ADAPTIVE RESPONSE AND CANCER RISK ASSESSMENT FOR RADIATION AND CHEMICAL EXPOSURES

Science.gov (United States)

There is an increased interest in utilizing mechanistic data in support of the cancer risk assessment process for ionizing radiation and environmental chemical exposures. In this regard the use of biologically based dose-response models is particularly advocated. The aim is to pr...

Disk shaped radiation sources for education purposes made of chemical fertilizer

International Nuclear Information System (INIS)

Kawano, Takao

2008-01-01

A method for fabricating a disk-shaped radiation source from material containing natural radioisotopes was developed. In this compression and formation method, a certain amount of powdered material is placed in a stainless steel formwork and compressed to form a solid disk. Using this method, educational radiation sources were fabricated using commercially available chemical fertilizers that naturally contain the radionuclide, 40 K, which emits either beta or gamma rays, at each disintegration. The compression and formation method was evaluated by inspecting eleven radiation sources thus fabricated. Then the suitability of the fertilizer radiation source as an education aid was evaluated. The results showed that the method could be used to fabricate radiation sources without the need for learning special skills or techniques. It was also found that the potassium fertilizer radiation source could be used to demonstrate that the inverse-square law can be applied to the distance between the radiation source and detector, and that an exponential relationship can be seen between the shielding effectiveness and the total thickness of the shielding materials. It is concluded that a natural fertilizer radiation source is an appropriate aid for demonstrating the characteristics of radiation. (author)

Effects of Ramped Wall Temperature on Unsteady Two-Dimensional Flow Past a Vertical Plate with Thermal Radiation and Chemical Reaction

Directory of Open Access Journals (Sweden)

V. Rajesh

2014-08-01

Full Text Available The interaction of free convection with thermal radiation of a viscous incompressible unsteady flow past a vertical plate with ramped wall temperature and mass diffusion is presented here, taking into account the homogeneous chemical reaction of first order. The fluid is gray, absorbing-emitting but non-scattering medium and the Rosseland approximation is used to describe the radiative flux in the energy equation. The dimensionless governing equations are solved using an implicit finite-difference method of the Crank-Nicolson type, which is stable and convergent. The velocity profiles are compared with the available theoretical solution and are found to be in good agreement. Numerical results for the velocity, the temperature, the concentration, the local and average skin friction, the Nusselt number and Sherwood number are shown graphically. This work has wide application in chemical and power engineering and also in the study of vertical air flow into the atmosphere. The present results can be applied to an important class of flows in which the driving force for the flow is provided by combination of the thermal and chemical species diffusion effects.

Sulfate Aerosols from Non-Explosive Volcanoes: Chemical-Radiative Effects in the Troposphere and Lower Stratosphere

Directory of Open Access Journals (Sweden)

Giovanni Pitari

2016-06-01

Full Text Available SO2 and H2S are the two most important gas-phase sulfur species emitted by volcanoes, with a global amount from non-explosive emissions of the order 10 Tg-S/yr. These gases are readily oxidized forming SO42− aerosols, which effectively scatter the incoming solar radiation and cool the surface. They also perturb atmospheric chemistry by enhancing the NOx to HNO3 heterogeneous conversion via hydrolysis on the aerosol surface of N2O5 and Br-Cl nitrates. This reduces formation of tropospheric O3 and the OH to HO2 ratio, thus limiting the oxidation of CH4 and increasing its lifetime. In addition to this tropospheric chemistry perturbation, there is also an impact on the NOx heterogeneous chemistry in the lower stratosphere, due to vertical transport of volcanic SO2 up to the tropical tropopause layer. Furthermore, the stratospheric O3 formation and loss, as well as the NOx budget, may be slightly affected by the additional amount of upward diffused solar radiation and consequent increase of photolysis rates. Two multi-decadal time-slice runs of a climate-chemistry-aerosol model have been designed for studying these chemical-radiative effects. A tropopause mean global net radiative flux change (RF of −0.23 W·m−2 is calculated (including direct and indirect aerosol effects with a 14% increase of the global mean sulfate aerosol optical depth. A 5–15 ppt NOx decrease is found in the mid-troposphere subtropics and mid-latitudes and also from pole to pole in the lower stratosphere. The tropospheric NOx perturbation triggers a column O3 decrease of 0.5–1.5 DU and a 1.1% increase of the CH4 lifetime. The surface cooling induced by solar radiation scattering by the volcanic aerosols induces a tropospheric stabilization with reduced updraft velocities that produce ice supersaturation conditions in the upper troposphere. A global mean 0.9% decrease of the cirrus ice optical depth is calculated with an indirect RF of −0.08 W·m−2.

Radiation effects on ion exchange materials

Energy Technology Data Exchange (ETDEWEB)

Gangwer, T.E.; Goldstein, M.; Pillay, K.K.S.

1977-11-01

An extensive literature review and data compilation has been completed on the radiation-damage of ion exchange resins. The primary goal of the study has been to review the available literature on ion exchange materials used in, as well as those with potential for use in, the nuclear fuel and waste reprocessing areas. The physical and chemical properties of ion exchangers are reviewed. Experimental parameters useful in characterizing the effects of radiation on synthetic ion exchange resins are identified or defined. In compiling the diverse types of data, an effort was made to present the experimental data or experimentally based parameters in a format that would be useful for inter-comparing radiation effects on resins. When subject to radiation there are various general trends or qualitative effects displayed by the different types of resins. These radiation-trends and effects have been formulated into qualitative statements. The present day level of understanding of the behavior of resins under ionizing radiation is too limited to justify quantitative predictive modeling. The limitations and deficiencies of the literature are discussed and the experimentation needed to achieve quantitative modeling are outlined. 14 figs., 108 references.

Radiation effects on ion exchange materials

International Nuclear Information System (INIS)

Gangwer, T.E.; Goldstein, M.; Pillay, K.K.S.

1977-11-01

An extensive literature review and data compilation has been completed on the radiation-damage of ion exchange resins. The primary goal of the study has been to review the available literature on ion exchange materials used in, as well as those with potential for use in, the nuclear fuel and waste reprocessing areas. The physical and chemical properties of ion exchangers are reviewed. Experimental parameters useful in characterizing the effects of radiation on synthetic ion exchange resins are identified or defined. In compiling the diverse types of data, an effort was made to present the experimental data or experimentally based parameters in a format that would be useful for inter-comparing radiation effects on resins. When subject to radiation there are various general trends or qualitative effects displayed by the different types of resins. These radiation-trends and effects have been formulated into qualitative statements. The present day level of understanding of the behavior of resins under ionizing radiation is too limited to justify quantitative predictive modeling. The limitations and deficiencies of the literature are discussed and the experimentation needed to achieve quantitative modeling are outlined. 14 figs., 108 references

Chemical effects of ionizing radiation on the individual amino acids within intact and pure protein molecules. Final report

International Nuclear Information System (INIS)

Freidberg, F.

1977-01-01

Progress is reported on the following research projects: gamma radiation induced chemical and molecular weight changes in proteins; the free radical pattern for the irradiated protein; similarities in the mechanism of action of ionizing and of uv radiation; and spin trapping in the study of gamma radiolysis

Ionizing radiation biological effects and the proper protective measures against it's harmful effects

International Nuclear Information System (INIS)

Hhalel, A.M.

1990-01-01

This book intrduces a good knowledge in specifications of ionizing radiation biological effects and the proper protective measures againest harmful effectes. The book is devided in to five main sections, the first one introduces the hostorical bachground of the contributions of a number of scietists in the basic knolwledge of radiation and its biological effects. The second section deals with the physical and chemical principles of radiation the third one talks about radiation detection. While the fourth section talks (via seven chapter) about the effectes of ionizing radiation on living organisms molecules cells, tissues organs systems and the living organism the fifth section talks about the uses of radiation sources, the probability of radiation accidents, protective measures, international recommendations related to doses and safe use of ionizing radiation. (Abed Al-wali Al-ajlouni). 53 refs., 107 figs., 13 tabs

Kinetic theory of radiation effects

International Nuclear Information System (INIS)

Mansur, L.K.

1987-01-01

To help achieve the quantitative and mechanistic understanding of these processes, the kinetic theory of radiation effects has been developed in the DOE basic energy sciences radiation effects and fusion reactor materials programs, as well as in corresponding efforts in other countries. This discipline grapples with a very wide range of phenomena and draws on numerous sub-fields of theory such as defect physics, diffusion, elasticity, chemical reaction rates, phase transformations and thermodynamics. The theory is cast in a mathematical framework of continuum dynamics. Issues particularly relevant to the present inquiry can be viewed from the standpoints of applications of the theory and areas requiring further progress

Effects produced by nuclear radiation in powdery milk

International Nuclear Information System (INIS)

Urena N, F.; Reyes G, A.

1999-01-01

The objective of this work is to determine the chemical effects produced by the gamma rays and beta particles radiations on the powdery milk. This work treats on the Pre-dose analysis, sampling radiating, electron spin resonance, acidity, proteins, aminoacids, lactose, fatty acids, peroxides, as well as its experimental results. (Author)

Bystander effects and biota: implications of radiation-induced bystander effects for protection of the environment from ionising radiation

International Nuclear Information System (INIS)

Mothersill, C.E.; Seymour, C.B.

2003-01-01

Bystander effects are now known to be induced by both high and low LET in a variety of cells in culture. They have been proven to occur in vivo in mice following 0.5Gy total body irradiation and in blood from humans being treated for cancer by radiotherapy. Effects have also been detected in fish, crustacea and molluscs. The important questions now are not whether bystander effects occur but why and what implications they have, if any, for radiation protection. Different species and different genetic backgrounds within a species produce different types of bystander effect, different organs also produce different effects. This paper will review the data in this field and will discuss likely implications for protection of man and non-human biota. In particular it will look at the potential long-term outcomes for different organisational levels, from cell to ecosystem, of bystander mechanisms. In view of new concerns about the effects of low level radiation on non-human biota, emphasis will be placed on considering how bystander effects might operate at chronic low doses versus acute accidental low doses. Problems of radiation interaction with chemicals, whether chemicals can also induce 'bystander effects' , and how regulators might handle these situations which occur all the time in real environments, will be presented for discussion. Finally the paper will discuss likely implications of these mechanisms for evolutionary biology

Defence biochemical mechanisms of the organisms against chemical pollution and ionizing radiations

International Nuclear Information System (INIS)

Olinescu, Radu

2001-01-01

Acute exposure to high concentrations / doses of chemical pollutants and ionizing radiation usually kills giving no chance for survival, if not immediately, than later followed by specific diseases. Fortunately, this acute exposure is accidental, but chronic, low level exposure is also damaging. The involvement of pollution, especially of chemically produced, one in the etiology of several diseases is still under intensive research. Compared to other kinds of pollution (radioactive, microbiological), the chemical one seldom kills suddenly; it acts slowly, silently, by accumulation into the tissues, eventually inducing a failure of certain organ. The body is continuously adapting to low level concentrations of chemicals from environment until a certain threshold. All organisms, including humans, have a limited capacity of resisting the effects of various types of pollutants. Extensive laboratory research, demonstrated that most of damaging organic pollutants cause the formation of free radicals when they penetrate into the body and are metabolized. Free radicals are very reactive and are known to damage tissues with potentially fatal results. Substantial experimental evidence in recent years has demonstrated that all organisms are endowed with versatile, efficient antioxidant systems, that provide protection against the formation or effects of free radicals. However, the antioxidant systems are limited and when their capacity of protection is exceeded, injury resulting in illness or death occurs. In most cases, the harmful effects of chemicals on organisms depend on the biotransformation step, where free radicals are produced as byproducts of the metabolic reactions. The damaging effects of chemical pollutants are mostly restricted to an important organ depending on the way of penetration, nature of the compound and concentration. The organisms possess specific and nonspecific defense systems, which act from the exposure step, with attempt to block the entry of

Effect of physical, chemical and electro-kinetic properties of pumice samples on radiation shielding properties of pumice material

International Nuclear Information System (INIS)

Tapan, Mücip; Yalçın, Zeynel; İçelli, Orhan; Kara, Hüsnü; Orak, Salim; Özvan, Ali; Depci, Tolga

2014-01-01

Highlights: • Radiation shielding properties of pumice materials are studied. • The relationship between physical, chemical and electro-kinetic properties pumice samples is identified. • The photon atomic parameters are important for the absorber peculiarity of the pumices. - Abstract: Pumice has been used in cement, concrete, brick, and ceramic industries as an additive and aggregate material. In this study, some gamma-ray photon absorption parameters such as the total mass attenuation coefficients, effective atomic number and electronic density have been investigated for six different pumice samples. Numerous values of energy related parameters from low energy (1 keV) to high energy (100 MeV) were calculated using WinXCom programme. The relationship between radiation shielding properties of the pumice samples and their physical, chemical and electro-kinetic properties was evaluated using simple regression analysis. Simple regression analysis indicated a strong correlation between photon energy absorption parameters and density and SiO 2 , Fe 2 O 3 , CaO, MgO, TiO 2 content of pumice samples in this study. It is found that photon energy absorption parameters are not related to electro-kinetic properties of pumice samples

Chemical and catalytic effects of ion implantation

International Nuclear Information System (INIS)

Wolf, G.K.

1982-01-01

Energetic particles are used for inducing chemical reactions as well as for modifying the properties of materials with regard to their bulk and surface chemical behavior. The effects are partly caused by radiation damage or phase intermixing, partly by the chemical properties of the individual bombarding particles. In this contribution a survey of relevant applications of these techniques is presented: (1) Chemical reactions of implanted and recoil atoms and their use for syntheses, doping and labeling of compounds. (2) The formation of thin films by decomposing chemical compounds with ion beams. 3) Catalytic effects on substrates treated by sputtering or ion implantation. Recent results with nonmetallic substrates are reviewed. Mainly hydrogenation reactions at a solid/gas interface or redox reactions at an electrified solid/liquid interface are mentioned. The present status and future prospects of these kinds of investigations will be discussed. (author)

Harmful effects of ultraviolet radiation

International Nuclear Information System (INIS)

Anon.

1989-01-01

Tanning for cosmetic purposes by sunbathing or by using artificial tanning devices is widespread. The hazards associated with exposure to ultraviolet radiation are of concern to the medical profession. Depending on the amount and form of the radiation, as well as on the skin type of the individual exposed, ultraviolet radiation causes erythema, sunburn, photodamage (photoaging), photocarcinogenesis, damage to the eyes, alteration of the immune system of the skin, and chemical hypersensitivity. Skin cancers most commonly produced by ultraviolet radiation are basal and squamous cell carcinomas. There also is much circumstantial evidence that the increase in the incidence of cutaneous malignant melanoma during the past half century is related to increased sun exposure, but this has not been proved. Effective and cosmetically acceptable sunscreen preparations have been developed that can do much to prevent or reduce most harmful effects to ultraviolet radiation if they are applied properly and consistently. Other safety measures include (1) minimizing exposure to ultraviolet radiation, (2) being aware of reflective surfaces while in the sun, (3) wearing protective clothing, (4) avoiding use of artificial tanning devices, and (5) protecting infants and children

Analysis of mechanism of complex chemical reaction taking radiation chemical purification of gases from impurities as an example

International Nuclear Information System (INIS)

Gerasimov, G.Ya.; Makarov, V.N.

1997-01-01

Algorithm of selecting optimal mechanism of complex chemical reaction, enabling to reduce the number of its stages, is suggested. Main steps of constructing the kinetic model of the medium are considered, taking the radiation chemical purification (using fast electron radiation) of gases (N 2 , CO 2 , O 2 and others) from impurities as an example. 17 refs., 3 figs., 2 tabs

Effect of gamma-radiation on a water-insoluble arabinoxylan

International Nuclear Information System (INIS)

Ebringerová, A.; Pružinec, J.; Kačuráková, M.; Hromádková, Z.

1989-01-01

The effect of gamma radiation on a water-insoluble L-arabino-D-xylan has been studied by functional group and structural analysis using chemical methods and IR spectroscopy, by sugar composition analysis, and by viscosity measurements. The gamma irradiation has been shown to modify both sugar components of the arabinoxylan, accompanied by cleavage of the glycosidic linkages, depolymerization, and sugar decomposition, depending on the applied radiation dose, thus increasing the molecular and chemical heterogeneity of the polysaccharide. (author)

Action of certain chemical compounds on radiation haemolysis of erythrocytes

International Nuclear Information System (INIS)

Kolesnikov, Yu.A.; Shulgina, M.A.; Yartsev, E.I.; Novoseltseva, S.D.; Bogatyrev, G.P.

1975-01-01

A radioprotective action of a number of protective chemicals on radiation haemolysis of erythrocytes has been studied. S-bearing radioprotectors, serotonin and arginine possess the highest radioprotective activity. The same radioprotectors delivered to the medium after irradiation do not influence the development of the post-irradiation haemolysis. Certain amino acids, namely proline, serine and taurine have a pronounced radio-protective action when given to the medium after irradiation, taurine producing the strongest effect on the development of radiation haemolysis. The mechanism of action of these substances is unrelated to the increased osmotic pressure of the medium and might be explained by normalization of the functional state of cytomembranes and processes of cell metabolism

Effect of the gamma radiation on the chemical, rheological, baker and microbiological properties in wheat flour

International Nuclear Information System (INIS)

Agundez A, Z.; Fernandez R, M.V.; Arce C, M.E.; Cruz Z, E.; Chernov, V.; Barboza F, M.

2002-01-01

The gamma radiation has been used in several places of the World as a sterilization method, preservation and pasteurization of foodstuffs, effect which is achieved due to diminishing or elimination of the microorganisms, reaching every time more acceptance, moreover eliminates the uses of toxic and carcinogenic substances, of general use, but at the present, being in the process of being totally prohibited, due to the higher risk in the human health. In this work the related results with the effects of the gamma radiation are presented, coming from a 60 Co source, in commercial wheat flour exposed to a dose of 1.0 KGy. The used dose is that allowed according to the NOM-033-SSA1-1993 standard. It was determined that the chemical characteristics of humidity, protein and ashes were not affected by radiation. The rheological properties neither suffer severe effects as consequence of radiation; the pharynographic and alveographic parameters were lightly affected by the treatment. Significant changes were detected in the percentage of water absorption and in the tolerance index to mixing. However a diminish of 10% in the development time and an increase of 13% in the stability was observed, for the irradiated samples respect to the those samples not irradiated. In relation to the alveograph parameters it was only detected a diminish of 7% in the force parameter (w) without changes in the tenacity/blowing up index ratio (P/L). The fall number diminish 11% indicating a small diminution in viscosity. The bakering properties do not turn out modified by the irradiation treatment finding a specific weight of 4.6 and 4.5 (cm 3 /g) for the control and irradiated samples, respectively. In the mesophyll analysis it was found a diminish of 96% from the original charge in control samples, observing a diminution of 74 and 25% in yeasts and mushrooms respectively. Microbiologically it was determined absence of total coliforms bacteria and faecal coliforms in the control samples and of

Is radiation an appropriate model for chemical mutagenesis and carcinogenesis

International Nuclear Information System (INIS)

Bond, V.P.

1982-01-01

This chapter attempts to show why the quadratic, or ''linear quadratic,'' relationship holds for organ dose-single cell radiation effects, and to explore the extension of this relationship to chemical exposures in general. Demonstrates that although the ''αD + βD 2 relationship'' may be unexpected for normal pharmacologicalmedical dose-response relationships, a linear, no-threshold curve of this kind is expected for all stochastic-type (accidental or risk) situations with health consequences (e.g. all common accidents) including exposure to ''low-level radiation'' (LLR). Discusses the stochastic or risk approach, relevant radiobiology, and the stochastic for chemicals. Assumes that even though actual mutational rates cannot be expected to apply to the relevance of Tradescantia or any other single cell system as a predictor for mutagenesis and carcinogenesis in animals and man, the cardinal principles of genetics largely transcend species and the particular environment in which the cell is located. Concludes that with regard to LLR, the curve shapes and other relationships developed for Tradescantia would be expected to apply in principle to animal and human mutagenesis and carcinogenesis

Quantitative and qualitative changes in the lymphocytes of rats chronically exposed to radiation and chemical factors

International Nuclear Information System (INIS)

Ivanov, V.V.

1986-01-01

Quantitative and qualitative characteristics of lymphocytes in peripheral blood, thymus and spleen of rats chronically exposed to combined external γ-radiation trichlorfon pesticide effect have been studied. It is shown that chronical combined trichlorfon and γ irradiation effect is accompanied by suppression of lymphopoiesis already at the early stages of the experience. The observed effects are formed depending on both daily and cumulative doses of the effect. The development of the combined effect is based on the summation of effects of chronical effect of ionizing radiation and pesticide. The revealed changes in lymphocytes population exposed to radiation and chemical factors can lead to substantial decrease of natural immunity thereby decreasing to various diseases

The effects of acute joint exposure to radiation and certain pesticides on the peripheric blood in rats

International Nuclear Information System (INIS)

Ivanov, V.V.

1984-01-01

The effect of joint external γ-radiation and some pesticides on the peripheric blood is studied. Lindane, trichlorfon and tetramethylthiuram disulfide are used as toxic chemicals. It is shown that the combined effect has caused, like radiation, stable leukopenia, but less expressed than the effect of gamma radiation. It is especially obvious in the case of combining ionizing radiation and TMTD when the number of leukocytes averaged by 25% more than in the case of injury by radiation alone. Lymphocytes are most sensitive blood cell elements earily responsing to radiation and chemical organism injuries, both qualitatively and quantitatively. The results of analyzing the dynamics of the most qualitative and quantitative paramaters of leukocytes permit to state the summation of mutual effects of factors of radiation and chemical nature

Effect of radiation-induced modification in fluoroelastomer

International Nuclear Information System (INIS)

Zen, Heloisa Augusto; Lugao, Ademar Benevolo

2013-01-01

Polymers exposed to ionizing irradiation, even at low doses, often undergo structural changes accompanied by molecular crosslinking and chain scission (degradation) reactions. The general effect of the radiation on polymers is determined by the ratio of crosslinking to chain scission events. This ratio depends on parameters such as chemical structure, physical state, radicals stability and mobility, irradiation rate and irradiation atmosphere. The radiation process is a large used technique to promote modification in their structures to apply them in different areas and is well known for its merits and potential in modifying the chemical and the physical properties of polymeric materials without cause drastic changes in their inherent properties, depend on the dose irradiated. In this study was used fluoroelastomer with 70% - fluor that having excellent thermal, chemical and mechanical properties. Vulcanized and non-vulcanized samples of this material were submitted to gamma radiation under air atmosphere in order to observe the effect of atmosphere in the polymer matrix. The irradiated doses were 5, 10 and 20kGy, at room temperature. The characterization was made by scanning electron microscope (SEM), infrared spectroscopy using attenuate reflectance (ATR-IR) and X-ray diffraction. The results demonstrated which was expected, the degradation reactions were observed. (author)

Biochemical studies on the effect of radiation on plants

International Nuclear Information System (INIS)

Yonies, R.M.M.

1997-01-01

The effect of gamma radiation, microwave radiation, interaction between gamma and microwave radiation and storage of radiated oil seeds (soybean and sesame) were investigated in this study to find out the best treatment which have the maximum reduction of anti nutritional factors (Trypsin inhibitor and lipoxygenase activities) without significant effect on the chemical constituents. The gamma rays was used at three doses of 2.5, 5.0 and 8.0 K.Gy, microwave radiation was at 70 level power for 2 and 4 mins, and the storage of seeds was at rome temperature, R.H.50-55% for 6 months. The results showed no significant changes in the chemical constituents (ash, moisture, protein, carbohydrate, lipid) in both investigated seeds under all treatments. On the other hand, the best treatments which had highly significant reduction effects on the anti nutritional factors (trypsin inhibitor, tannins, phytic acis, phenols and lipoxygenase) were 8.0 K.Gy for 6 months, 4 mins M.W. for soybean, 2 mins M.W. for sesame and 8.0 K.Gy +4 mins M.W. at 6 months. 38 tabs., 39 figs., 279 refs

Physico-chemical effects of electron beam radiation on polypropylene film and its polyphenolic antioxydant

International Nuclear Information System (INIS)

Aymes-Chodur, C.; Legendre, B.; Yagoubi, N.; Betz, N.

2002-01-01

Complete text of publication follows. Even though plastics are widely used in various industrial applications, problems have occurred concerning the quality of the packaged products, due to the presence of potentially toxic additives that can migrate out of the polymer and thus contaminate the surrounding medium. This phenomenon is due to the fact that the additives are only mixed with the polymer powder before the plastic is molded, and as no chemical bond keeps them into the polymer matrix, additives are able to migrate as the plastic ages. In order to avoid this phenomenon, which can lead to the rejection of biomaterials, or food or drugs contamination problems, we intend to graft the additives into the polymer matrix by means of ionizing radiation. Indeed, previous studies have shown that radiation induces the formation of free radicals and hydroperoxides that can react with monomers to create covalent bonds. Our work deals with electron beam irradiation of polypropylene (PP) containing a known concentration of Irganox 1010, a polyphenolic antioxidant. High performance liquid chromatography (HPLC) measurements have been performed in order to evaluate the behavior of the additives under ionizing radiation, but the polymer matrix must also be characterized as a function of the absorbed radiation dose. This present study gives FTIR, high temperature size exclusion chromatography (SEC) and differential scanning calorimetry (DSC) results performed on both PP and Irganox 1010. They evidence the formation of oxidative groups such as free alcohols and hydroperoxides, and the formation of double bonds in the PP. SEC results highlight the scission of the polymer chains correlated to the degradation of the crystalline domains observed by DSC. Those physico-chemical modifications must be characterized for the understanding of the grafting and before the antioxidant activity is evaluated

Photo- and radiation-chemical stability of molecules. Reactions of monomolecular hydrogen atom splitting off

International Nuclear Information System (INIS)

Plotnikov, V.G.; Ovchinnikov, A.A.

1978-01-01

In the review of works published up to 1978 one of the main problems of radiation chemistry is discussed, namely the relationship between the structure of organic molecules and their resistance to the effect of ionizing radiation. Theoretical aspects of this problem are considered for reactions of monomolecular hydrogen atom splitting off. It is shown that the radical yield in low-temperature radiation-chemical experiments is connected with the position of lower triplet states of molecules, ionization potentials, polarity of medium and the energy of C-H bonds in cation radicals

Problems and solutions in the estimation of genetic risks from radiation and chemicals

International Nuclear Information System (INIS)

Russell, W.L.

1980-01-01

Extensive investigations with mice on the effects of various physical and biological factors, such as dose rate, sex and cell stage, on radiation-induced mutation have provided an evaluation of the genetics hazards of radiation in man. The mutational results obtained in both sexes with progressive lowering of the radiation dose rate have permitted estimation of the mutation frequency expected under the low-level radiation conditions of most human exposure. Supplementing the studies on mutation frequency are investigations on the phenotypic effects of mutations in mice, particularly anatomical disorders of the skeleton, which allow an estimation of the degree of human handicap associated with the occurrence of parallel defects in man. Estimation of the genetic risk from chemical mutagens is much more difficult, and the research is much less advanced. Results on transmitted mutations in mice indicate a poor correlation with mutation induction in non-mammalian organisms

Radiation treatment of toxic chemicals

International Nuclear Information System (INIS)

Lee, M.J.; Jung, I.H.; Jo, S.K.

2010-01-01

Polychlorinated biphenyls (PCBs) were commercially produced from 1920s as complex mixtures containing multiple isomers for a variety of applications. They are very toxic, chemically stable and resist microbial, photochemical, chemical, and thermal degradation. The public, legal, and scientific concerns about PCBs arose from research indicating they were environmental contaminants that had a potential to adversely impact the environment, and, therefore, were undesirable as commercial products. Eventually, most producers reduced or stopped production of PCBs in the 1970s. Stockholm convention on POPs (Persistent Organic Pollutants), which was effective on May 2004 and 151 nations including Korea were joined on June 2005, asked to dispose of PCBs by 2028 with environmental friendly methods. Korean government also has declared to conduct by 2015. According to the Environmental law of Korea, over 2 ppm of PCBs has to be decomposed by legal methods of incineration and thermal destruction. But those are inapplicable owing to the environmental groups. KAERI(Korea Atomic Energy Research Institute) has recently developed a remarkable technology for radiation treatment of toxic chemicals including chlorides using an electron beam accelerator. Electron beam accelerator of 2.5 MeV energy and 100 kW power capacity was used to decompose of PCBs having been used as a commercial transformer oil for more than 30 years. The oil were irradiated with ∼ 0.1 percent of TEA (Triethyl Amin) to make chloride ion aparted off from the PCBs into precipitate at the conditions of normal temperature and pressure. The concentrations of PCBs were measured by GC (Gas Chromatography) with ECD (Electron Capture Detector) following the KS (Korean Standard) test procedure. Electron beam should be a useful tool for environmental conservation. Residual concentrations of PCBs after irradiation were depended on the absorption dose of electron beam energy. Advantages comparing to other methods such as

CHEMICAL VAPOUR DEPOSITION FROM A RADIATION-SENSITIVE PRECURSOR

DEFF Research Database (Denmark)

2017-01-01

The present invention relates in one aspect to a method of depositing a thin film on a substrate by chemical vapour deposition (CVD) from a radiation-sensitive precursor substance. The method comprises the steps of: (i) placing the substrate in a reaction chamber of a CVD system; (ii) heating...... heating pulse followed by an idle period; (iii) during at least one of the idle periods, providing a pressure pulse of precursor substance inside the reaction chamber by feeding at least one precursor substance to the reaction chamber so as to establish a reaction partial pressure for thin film deposition...... is formed. According to a further aspect, the invention relates to a chemical vapour deposition (CVD) system for depositing a thin film onto a substrate using precursor substances containing at least one radiation sensitive species....

Recovery during radiation and chemical mutagenesis

International Nuclear Information System (INIS)

Deen, D.F.

1975-01-01

These investigations were directed toward the study of recovery in radiation and chemical mutagenesis in cultured mammalian cells. A mutagenesis system was established in which mutation of V79-17lb Chinese hamster cells to 8-azaguanine resistance was tested. The effects of split dose and postirradiation treatments upon both x-ray and EMS induced mutagenesis were determined. Increasing the cell inoculum by a factor of 5 (from 10 5 to 5 x 10 5 ) decreased both the spontaneous and x-ray induced mutation frequencies by two orders of magnitude. The x-ray induced mutation frequency was found to be higher for those cells allowed to attach for 5 hours before irradiation, in comparison to those allowed to attach for 2 hours. The uv spectrum of 8-azaguanine changes as a function of storage time at low temperature, but not when diluted to either 10 μg/ml or 30 μg/ml and maintained at 37 0 C. The optimal expression time required after irradiation is dose dependent and can be determined from the relationship: E.T. = 1.93(10 -2 )D + 15.5. (E.T. = hours; D = rads). The duration of the optimal expression time can be estimated by summing the cell cycle time and the radiation induced lag time

Cost effectiveness of dilute chemical decontamination

International Nuclear Information System (INIS)

LeSurf, J.E.; Weyman, G.D.

The basic principles of dilute chemical decontamination are described, as well as the method of application. Methods of computing savings in radiation dose and costs are presented, with results from actual experience and illustrative examples. It is concluded that dilute chemical decontamination is beneficial in many cases. It reduces radiation exposure of workers, saves money, and simplifies maintenance work

In vitro transformation: interactions of chemical carcinogens and radiation

International Nuclear Information System (INIS)

DiPaolo, J.A.

1976-01-01

The development of reproducible quantitative in vitro procedures resulting in neoplastic transformation of mammalian cells has made possible the separation of events related to the process leading to transformation from secondary events that interfere with the early recognition of transformation. The use of chemical carcinogens on Syrian hamster cell strains results in a dose-response relation consistent with a Poisson distribution, indicating that the transformation phenomenon is inductive. In some circumstances, the joint action or interaction of chemical carcinogens with other agents results in an increased incidence of transformation. The pretreatment of Syrian hamster cells with ionizing radiation (250 R) or alkylating chemicals enhances the frequency of transformation on a cell or colony basis ordinarily obtained with known chemical carcinogens. Pretreatment with non-ionizing irradiation (uv, 254 nm) did not have a similar effect. The two types of irradiation and the alkylating agents reduced the cloning efficiency of the cells. X ray alone produced no transformation; the alkylating chemicals produced transformations infrequently, whereas uv produced a significant number of transformations. The number of transformations associated with uv is increased by pretreatment of the cells by x-irradiation. The enhancement of transformation by x-ray or x-ray-type agents appears to be independent of the type of second carcinogen used

Physico-chemical studies of radiation effects in cells. Progress report, February 15, 1982-February 14, 1983

International Nuclear Information System (INIS)

Powers, E.L.

1982-01-01

Progress in studies investigating the chemical mechanisms involved in radiation-induced cellular damage is reported. Three organisms currently being tested are Bacillus megaterium, Bacillus subtilis, and Escherichia coli, silver and mercury have been used as radiosensitizers, and their interaction with DNA studied

The Effect of MHD on Free Convection with Periodic Temperature and Concentration in the Presence of Thermal Radiation and Chemical Reaction

Directory of Open Access Journals (Sweden)

Zigta B.

2017-12-01

Full Text Available This paper studies the effect of magneto hydrodynamics on unsteady free convection between a pair of infinite vertical Couette plates. The temperature of the plates and concentration between the plates vary with time. Convection between the plates is considered in the presence of thermal radiation and chemical reaction. The solution is obtained using perturbation techniques. These techniques are used to transform nonlinear coupled partial differential equations to a system of ordinary differential equations. The resulting equations are solved analytically. The solution is expressed in terms of power series with some small parameter. The effect of various parameters, viz., velocity, temperature and concentration, has been discussed. Mat lab code simulation study is carried out to support the theoretical results. The result shows that as the thermal radiation parameter R increases, the temperature decreases near the moving porous plate while it approaches to a zero in the region close to the boundary layer of the stationary plate. Moreover, as the modified Grashof number, i.e., based on concentration difference, increases, the velocity of the fluid flow increases hence the concentration decreases. An increase in both the chemical reaction parameter and Schmidt number results in decreased concentration.

The Effect of MHD on Free Convection with Periodic Temperature and Concentration in the Presence of Thermal Radiation and Chemical Reaction

Science.gov (United States)

Zigta, B.; Koya, P. R.

2017-12-01

This paper studies the effect of magneto hydrodynamics on unsteady free convection between a pair of infinite vertical Couette plates. The temperature of the plates and concentration between the plates vary with time. Convection between the plates is considered in the presence of thermal radiation and chemical reaction. The solution is obtained using perturbation techniques. These techniques are used to transform nonlinear coupled partial differential equations to a system of ordinary differential equations. The resulting equations are solved analytically. The solution is expressed in terms of power series with some small parameter. The effect of various parameters, viz., velocity, temperature and concentration, has been discussed. Mat lab code simulation study is carried out to support the theoretical results. The result shows that as the thermal radiation parameter R increases, the temperature decreases near the moving porous plate while it approaches to a zero in the region close to the boundary layer of the stationary plate. Moreover, as the modified Grashof number, i.e., based on concentration difference, increases, the velocity of the fluid flow increases hence the concentration decreases. An increase in both the chemical reaction parameter and Schmidt number results in decreased concentration.

Effects of Thermal Radiation and Chemical Reaction on MHD Free Convection Flow past a Flat Plate with Heat Source and Convective Surface Boundary Condition

OpenAIRE

E.Hemalatha; N. Bhaskar Reddy

2015-01-01

This paper analyzes the radiation and chemical reaction effects on MHD steady two-dimensional laminar viscous incompressible radiating boundary layer flow over a flat plate in the presence of internal heat generation and convective boundary condition. It is assumed that lower surface of the plate is in contact with a hot fluid while a stream of cold fluid flows steadily over the upper surface with a heat source that decays exponentially. The Rosseland approximation is used to desc...

Physico-chemical studies of radiation effects in cells. Progress report, November 15, 1980-February 14, 1984

International Nuclear Information System (INIS)

Powers, E.L.

1983-01-01

The primary interest is investigating and understanding the chemical mechanisms involved in radiation-induced cellular damage. Most recently the perturbating devices have been metals which increase, in various ways and modes, the radiation sensitivity of several cell types. While the chief cell type has been the bacterial spore, chosen because of its biological inertness and its hardiness, allowing it to survive the unphysiological conditions of the physical chemist and, thus, inquiry into the free radical mechanisms involved very soon after energy absorption, recently vegetative cells have been introduced. A number of metals have been used and practically all of them sensitize - but to varying degrees. Straight biological techniques such as the measurement of cell survival under various conditions in the different cells have been used, as well as parallel experiments in pulse radiolysis to attack the specific leads in a chemical fashion suggested by the biology

Influence of vitamins on cytostatic drugs: radiation-chemical and radiation-biological investigations in vitro

International Nuclear Information System (INIS)

Heinrich, E.

2002-03-01

Many environmental burdens (air pollution, formation of ozone etc.), humans nowadays are exposed to, in connection with unhealthy way of living promote the formation of free radicals e.g. OH and peroxylradicals in the organism. Those show an enormous cell-damaging effect, and can weaken the immune system or cause cancer diseases. The number of humans suffering from different forms of cancer is rising world-wide. Therefore it is necessary to find new and better therapy forms for this illness. The organism has its own protective system, which is able to capture free radicals and make them innocuous to a large extent. Apart from various enzyme systems the antioxidizing vitamins C (ascorbic acid), E (α-tocopherol) and β-carotin play an important role in this process. Now it was of interest whether vitamin B1 (thiamine) also possesses the ability to work as a radiation protector or to influence the effect of different cytostatic drugs. In the context of this thesis the radiation-chemical and radiation-biological behaviour of vitamin B1 was examined under different conditions (in presence and absence of oxygen as well as in media saturated with N 2 O). HPLC analysis were performed to establish radiolysis products. Furthermore the synergistic effect of vitamin B1 on cytostatic drugs (sanazole, mitomycin C) was studied alone or in combination with other vitamins (C, E and β-carotin) by using two different E. coli bacteria strains as a model for living systems. (author)

Application of spectroscopic methods to the study of ionizing radiation effects in polymers

International Nuclear Information System (INIS)

Jimenez P, G.

1995-01-01

In general the interaction of ionizing radiation with polymers generates physic-chemical changes. Aiming to quantity these changes, three spectroscopic analytical techniques were used (UV, IR and EPR) and the chemical corrosion technique was used for three DSTN (CR39, Lexan and Makrofol) which were exposed to two radiation types: electrons and gammas. The effects of radiation are compared. Also a correlation between the UV and Vg results in function of dose is presented. The possible causes of the increase in chemical corrosion are discussed. (Author)

Radiochemical problems of radiation chemical synthesis in n, γ-field of nuclear reactor

International Nuclear Information System (INIS)

Mironov, V.P.; Frejdus, N.V.; Bugaenko, L.T.; Kalyazin, E.P.; Petryaev, E.P.

1981-01-01

A wide applicability of products of radiation chemical synthesis (RCS), using n, γ-irradiation, is limited by possible contamination of the latter with long-lived radioactive isotopes of chemical elements included in the composition of the reagent and compounds syntesized (chemically non-separable radionuclides - CNR). A technique of the determination of the limit accumulation CNR on the basis of radiation chemical parameters of the synthesis (radiation-chemical yield, the dose rate absorbed, singleness of purpose of RCS etc.) and radiochemical parameters of formation and accumulation of CNR (radiochemical yields of CNR in the products of radiolysis, neutron fluence, the reagent purity etc.) is suggested. The radiochemical evaluation of CNR accumulation (tritium and carbon-14), formed at the expense of activation with neutrons of chemical elements of water and organic substances, consisting of hydrogen, carbon and oxygen has shown that at relatively low yields of final products (> or approximately 3 molecules/100 eV) no accumulation of radionuclides in concentrations reaching the average admissible concentration takes place [ru

Estimation of the optimal operating conditions for a radiation chemical neutralization unit

International Nuclear Information System (INIS)

Putilov, A.V.; Kamenetskaya, S.A.; Pshezhetskii, S.Ya.; Kazakov, M.S.; Kudryavtsev, S.L.; Petrukhin, N.V.; Misharin, B.A.; Koneev, V.Z.

1985-01-01

An estimate is made of the effect of the hydrodynamic conditions on the efficiency of foam units for the radiation chemical neutralization of impurities, taking into account the penetrating power of accelerated electrons having various energies. Expressions are obtained for calculating the efficiency of such units with sectionized operation of the chamber and taking account of the effect of incomplete mixing of the products of radiolysis through the height of the foam layer

Direct and indirect effects of radiation on polar solid solutions

International Nuclear Information System (INIS)

Ershov, V.G.; Gaponova, I.S.

1982-01-01

Radiation-chemical decomposition of a solute is due to the direct effect of ionizing radiation on it and also to its reaction with radical-ion products of radiolysis of the solution. At low temperature, the movement of the reagents is limited, and thus it is possible to isolate and evaluate the contribution of direct and indirect effects of radiation on the solute. The present paper is devoted to an investigation of the mechanism of formation of radicals from a solute (LiNO 2 ) in a polar solid solution (CH 3 OH) under the effect of γ-radiation

Chemical Modifications of Starch: Microwave Effect

Directory of Open Access Journals (Sweden)

Kamila Lewicka

2015-01-01

Full Text Available This paper presents basic methods of starch chemical modification, the effect of microwave radiation on the modification process, and the physicochemical properties of starch. It has been shown that the modifications contribute to improvement of the material performance and likewise to significant improvement of its mechanical properties. As a result, more and more extensive use of starch is possible in various industries. In addition, methods of oxidized starch and starch esters preparation are discussed. Properties of microwave radiation and its impact on starch (with particular regard to modifications described in literature are characterized.

Mutation induction in rice by radiation combined with chemical protectants and mutagens

Energy Technology Data Exchange (ETDEWEB)

Ando, A [Agricultural College, University of Sao Paulo, Sao Paulo (Brazil)

1970-03-01

Seeds of the rice variety 'Dourado Precoce' were treated with different combinations of gamma rays, cysteine and EMS or gamma rays, cysteine and dES. Cysteine showed some protection against the effects of gamma radiation and combined gamma-ray + chemical treatments with regard to germination, seedling height and fertility. There are also indications of changes in the spectra of chlorophyll mutations. (author)

Natural radiation, radioactive waste and chemical risk determinants

International Nuclear Information System (INIS)

Christensen, T.; Mustonen, R.; Edhwall, H.; Hansen, H.; Soerensen, A.; Stranden, E.

1990-01-01

Doses from natural radiation to the population in the Nordic countries are summarized, and man-made modifications of the natural radiation environment are discussed. An account is given for the radiological concequences of energy concervation by reduced ventilation. Risks from possible future releases of radioactivity from final depositories of spent nuclear fuel are compared to the risks from present natural radioactivity in the environment. The possibilities for comparison between chemical and radiological risks are discussed. 104 refs., 36 figs., 47 tabs

The effect of radiation-sterilization conditions and preservation procedures on physico-chemical and biological properties of bone allografts

International Nuclear Information System (INIS)

Goclawska, A.D.; Kaminski, A.; Wasilewska, M.

1999-01-01

Radiation-sterilization of connective tissue allografts (bone including) with a dose of 35 kGy is routinely used in the Central Tissue Bank in Warsaw since 1963. This method of sterilization offers many advantages: good penetration ability, relatively low temperature rise, and possibility of sterilization of grafts in closed beforehand vials, which protects against secondary contamination. It should be kept in mind, however that high doses of ionizing radiation (in the range of 20-35 kGy) used for sterilization evoke many chemical and physical changes which may influence biological properties of grafts. These changes have been studied using various methodological approaches. Using electron paramagnetic resonance (EPR) spectrometry it has been found that in radiation-sterilized bone two types of paramagnetic entities are generated: i/ coliagen radicals which are unstable and disappear completely in the presence of air oxygen, ii/ very stable at room temperature paramagnetic defects (centers) localized in the crystalline lattice of bone mineral. These stable paramagnetic defects have been treated as a new kind of markers and used for: a/ quantitative evaluation of remodeling process of radiation-sterilized bone allografts preserved by lyophilization or deep freezing; b/ estimation of the dose of ionizing radiation absorbed by living organism in the case of accidental exposure (skeleton serving as a dosimeter) and for control of radiation-sterilization process. The effect of radiation-sterilization and preservation procedures on bone allografts was studied using a model of heterotopically induced osteogenesis and measuring the solubility of bone collagen in vitro. It has been observed that lyophilized bone allografts irradiated at room temp. with doses of 35 and 50 kGy, respectively, were very quickly resorbed in vivo and did not induce osteogenesis, while lyophilized as well as deep-frozen matrices irradiated at -7OoC were slowly resorbed and induced de novo bone fon

Study the effect of chemical reaction and variable viscosity on free convection MHD radiating flow over an inclined plate bounded by porous medium

Energy Technology Data Exchange (ETDEWEB)

Ali, M., E-mail: ali.mehidi93@gmail.com [Department of Mathematics, Bangladesh University of Engineering and Technology, Dhaka-1000 (Bangladesh); Department of Mathematics, Chittagong University of Engineering and Technology, Chittagong-4349 (Bangladesh); Alim, M. A., E-mail: maalim@math.buet.ac.bd; Nasrin, R., E-mail: rehena@math.buet.ac.bd [Department of Mathematics, Bangladesh University of Engineering and Technology, Dhaka-1000 (Bangladesh); Alam, M. S., E-mail: shahalammaths@gmail.com [Department of Mathematics, Chittagong University of Engineering and Technology, Chittagong-4349 (Bangladesh)

2016-07-12

An analysis is performed to study the free convection heat and mass transfer flow of an electrically conducting incompressible viscous fluid about a semi-infinite inclined porous plate under the action of radiation, chemical reaction in presence of magnetic field with variable viscosity. The dimensionless governing equations are steady, two-dimensional coupled and non-linear ordinary differential equation. Nachtsgeim-Swigert shooting iteration technique along with Runge-Kutta integration scheme is used to solve the non-dimensional governing equations. The effects of magnetic parameter, viscosity parameter and chemical reaction parameter on velocity, temperature and concentration profiles are discussed numerically and shown graphically. Therefore, the results of velocity profile decreases for increasing values of magnetic parameter and viscosity parameter but there is no effect for reaction parameter. The temperature profile decreases in presence of magnetic parameter, viscosity parameter and Prandtl number but increases for radiation parameter. Also, concentration profile decreases for the increasing values of magnetic parameter, viscosity parameter and reaction parameter. All numerical calculations are done with respect to salt water and fixed angle of inclination of the plate.

Study the effect of chemical reaction and variable viscosity on free convection MHD radiating flow over an inclined plate bounded by porous medium

International Nuclear Information System (INIS)

Ali, M.; Alim, M. A.; Nasrin, R.; Alam, M. S.

2016-01-01

An analysis is performed to study the free convection heat and mass transfer flow of an electrically conducting incompressible viscous fluid about a semi-infinite inclined porous plate under the action of radiation, chemical reaction in presence of magnetic field with variable viscosity. The dimensionless governing equations are steady, two-dimensional coupled and non-linear ordinary differential equation. Nachtsgeim-Swigert shooting iteration technique along with Runge-Kutta integration scheme is used to solve the non-dimensional governing equations. The effects of magnetic parameter, viscosity parameter and chemical reaction parameter on velocity, temperature and concentration profiles are discussed numerically and shown graphically. Therefore, the results of velocity profile decreases for increasing values of magnetic parameter and viscosity parameter but there is no effect for reaction parameter. The temperature profile decreases in presence of magnetic parameter, viscosity parameter and Prandtl number but increases for radiation parameter. Also, concentration profile decreases for the increasing values of magnetic parameter, viscosity parameter and reaction parameter. All numerical calculations are done with respect to salt water and fixed angle of inclination of the plate.

Changes of some indicators of cellular immunity in rats under their chronic radiation and chemical exposure

International Nuclear Information System (INIS)

Shvedov, V.L.; Anisimova, G.G.

1989-01-01

The experiments on rats exposed separately and in combination to radiation and chemical substances showed that the time of body pesticide intake (the total dose) was the leading factor affecting the phagocytosis indices. A daily pesticide dose had a credible impact on some indices. The combined effect was formed primarily due to chemical compounds. In general the effect could be regarded as less than additive though at some time it was additive and more than that

The effect of preplanting gamma radiation on chemical constitutents of peppermint oil

International Nuclear Information System (INIS)

Eissa, A.I.; El-Kholei, S.A.; Ragab, M.A.; Abou El-Seoud, M.A.

1984-01-01

Uniformly selected stem cuttings of peppermint (Mentha piperita L) were exposed to 0, 0.5, 1.0, 2.0 and 4.0 Krad of gamma rays from a Co 60 source and subsequently grown in field. Irradiation dose of 1.0 Krad was the best stimulatory dose for enhancing herb fresh weight as it resulted in almost two folds yield as compared with control, whereas dose of 4.0 Krad did not affect plant growth. One Krad treated plants induced higher yield of essential oil as compared with other radiation treatments and control. The major chemical constitutents (menthol, menthone and menthyl acetate) were statistically affected by developmental stages, and by pre-planting irradiation treatments as expressed on the total content basis. Higher contents of menthol, menthone and menthyl acetate were found in plant cut during flowering stage. Pre-planting gamma irradiation did not seem to affect both chemical ''acid value, ester value and saponification value'' and physical properties ''specific gravity, solubility and refractive index'' of extracted mint oil

UV inactivation: Combined effects of UV radiation and xenobiotics in two strains of Saccharomyces

International Nuclear Information System (INIS)

Lochmann, E.R.; Lochmann, G.

1997-01-01

The effects of eight chemicals on the inactivation rate of ultraviolet radiation on the colony building capabilities of two strains of Saccharomyces cervisae - a wild type strain and a mutant deficient in excision repair - were studied. The insecticide methoxychlor, the herbicide 2,4-dichlorophenoxyacetic acid, the fungicide pentachlorophenol and its metabolite tetrachlorohydroquinone, as well as the chemicals acrylonitrile and 2,3-dichloro-1-propene have no significant impact on the effects of UV radiation in Saccharomyces cerevisae. Depending on the concentration, trichloroethylene increases the sensitivity to UV radiation. The herbicide paraquat provides efficient protection against UV radiation at concentrations where a toxic effect cannot be observed even without UV. The results were rather similar for both strains. (orig.) [de

Radiation-chemical yields of molecular hydrogen formation in cyclohexane based alcohols

International Nuclear Information System (INIS)

Val'ter, A.I.; Kovalev, G.V.

1988-01-01

Molecular hydrogen radiation-chemical yields in γ-irradiated cyclohexanol, 1.2-cis- and 1.2-trans-cyclohexandiols and inositol are determined within the general problem frameworks of radiolysis mechanism for cyclohexanering-base alcohols. Irradiation was conducted at 77 and 293 K, dose rate - 4 Gy/s. Hydrogen concentration in all irradiated alcohols depends linearly on the dose. Radiation-chemical yields of H 2 and of stabilized radicals, as well, in the irradiated crystalline alcohols are analyzed depending on the irradiation temperature, alcohol molecular structure

Germ cell toxicity: significance in genetic and fertility effects of radiation and chemicals

International Nuclear Information System (INIS)

Oakberg, E.F.

1983-01-01

The response of the male and female to radiation and chemicals is different. Any loss of oocytes in the female cannot be replaced, and if severe enough, will result in a shortening of the reproductive span. In the male, a temporary sterile period may be induced owing to destruction of the differentiating spermatogonia, but the stem cells are the most resistant spermatogonial type, are capable of repopulating the seminiferous epithelium, and fertility usually returns. The response of both the male and female changes with development of the embryonic to the adult gonad, and with differentiation and maturation in the adult. The primordial germ cells, early oocytes, and differentiating spermatogonia of the adult male are unusually sensitive to the cytotoxic action of noxious agents, but each agent elicits a specific response owing to the intricate biochemical and physiological changes associated with development and maturation of the gametes. The relationship of germ cell killing to fertility is direct, and long-term fertility effects can be predicted from histological analysis of the gonads. The relationship to genetic effects, on the other hand, is indirect, and acts primarily by limiting the cell stages available for testing, by affecting the distribution of mitotically active stem cells among the different stages of the mitotic cycle, and thereby, changing both the type and frequency of genetic effects observed. 100 references, 38 figures, 7 tables

Radiation, chemical and biological protection. Mass destruction weapons

International Nuclear Information System (INIS)

Janasek, D.; Svetlik, J.

2005-01-01

In this text-book mass destruction weapons and radiation, chemical and biological protection are reviewed. The text-book contains the following chapter: (1) Mass destruction weapons; (2) Matter and material; (3) Radioactive materials; (4) Toxic materials; (5) Biological resources; (6) Nuclear energetic equipment; Appendices; References.

Features of radiation chemical processes in ethylene-styrene copolymers

International Nuclear Information System (INIS)

Leshchenko, S.S.; Mal'tseva, A.P.; Iskakov, L.I.; Karpov, V.L.

1976-01-01

A study was made of statistical copolymers of ethylene with styrene to determine their structure and properties and radio-chemical transformations. The styrene content of the copolymers ranged from 1 to 85 mole%. The investigation covered non-irradiated copolymers and those irradiated with doses of 1-1000Mrad at room temperature and at liquid nitrogen temperature. It is shown that styrene units present in the CES inhibited all radio-chemical processes compared with PE irradiated under similar conditions. It is suggested that the radiation resistance of CES with styrene contents up to 10 mole % increases in the course of irradiation as a result of the formation of structures with a high degree of conjugation which are more capable of scattering absorbed energy than in the case of phenyl rings by themselves. The most promising of the CES examined is the one with a styrene content of 5 mole %. The mechanical properties of this copolymer are similar to those of PE, and its radiation resistance rises under service conditions in the presence of ionizing radiation

Study of the mechanism of radiation-chemical transformations in rubber-resinous materials

International Nuclear Information System (INIS)

Sharova, L.B.; Astakhova, L.G. Trufanova, N.D.; Persinen, A.A.; Vasil'ev, I.A.

1993-01-01

Materials based on butadiene-nitrile rubbers reinforced by phenol-formaldehyde resins presently find wide application as reliable heat-insulating coatings for various metallic constructions and are utilized under exposure to ionizing radiation. In this connection, when estimating the assured lifetime of heat-insulating coatings, it is necessary to take into account the character and degree of their radiation-chemical transformations. The aim of the present work was to study the radiation-chemical transformations of materials based on a composite of butadiene-nitrile rubber and phenol-formaldehyde resin. The investigations were carried out on model materials S-O, S-25, S-100, S-130, and S-150 based on the SKN-40M rubber with a varied content of SF-010A brand phenol-formaldehyde resin, the content of which in parts by weight per 100 parts by weight of rubber is indicated in the specifications of the materials. The possible directions of the radiation-chemical transformations in the rubber-resinous vulcanizates were studied by the method of disrupted total internal reflection (MDTIR) IR spectroscopy

Delayed effects of nuclear and chemical weapons in man

International Nuclear Information System (INIS)

Dienstbier, Z.

1984-01-01

Delayed radiation effects are discussed of the use of nuclear and chemical weapons (defoliants and herbicides). Attention is drawn to the development of delayed malignities in exposed subjects and their pathophysiologic causes are explained. The only prevention of these effects is to prohibit the use of weapons of mass destruction. (author)

Genetic effects of formaldehyde in yeast. Current status and limitations of the radiation equivalence concept

International Nuclear Information System (INIS)

Chanet, R.; Magana-Schwencke, N.; Moustacchi, E.

1980-01-01

Values of radiation equivalents of chemicals have been calculated for formaldehyde (FA) from detailed data on its genetic effects on yeast, Saccharomyces cerevisiae, and compared with the effects induced by gamma radiation. For the haploid yeast strain, 1 (mmol FA.ltr -1 ).min (i.e. 1 mM FA.min) is equivalent to 9.6 rad, and for diploid yeast it is equivalent to 33 rad. These values are within the range of values calculated for E. coli and mammalian cells. Some major differences in the response to FA and radiation are encountered, depending upon the cellular physiological conditions, the genetic background and the degree of ploidy (haploid versus diploid) and growth phase (exponential versus stationary), among others. Difficulties encountered in the estimation of rad-equivalent values for specific chemicals and for defined biological end-points (e.g. rate of reverse mutation in the specific biochemical loci) are discussed. It is concluded that by exercising appropriate caution relating to the differences in the mechanisms of action of the chemical mutagens and radiations, meaningful rad-equivalent values could be estimated that could help express the comparative biological effects of chemicals in terms of radiation unit. (author)

Gamma-radiation effect on thermal ageing of butyl rubber compounds

Energy Technology Data Exchange (ETDEWEB)

Scagliusi, Sandra R.; Cardoso, Elizabeth C.L.; Lugao, Ademar B., E-mail: srscagliusi@ipen.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

2015-07-01

Butyl rubber has a comprehensive use in sealing systems, especially in tires inner tubes, due to their low permeability to gases. So, it is required that butyl rubber compounds show a better performance, more and more. Butyl rubber is provided with excellent mechanical properties and oxidation resistance. Besides showing these properties, radiation exposures impart modifications in physical-chemical and morphological properties on butyl rubber materials. When exposed to gamma-radiation, rubbers suffer changes in their mechanical and physical properties, caused by material degradation. The major radiation effect in butyl rubbers is chain scission; besides, ageing promotes too the same effect with further build-up of free radicals. This work aims to the study of gamma-radiation in physical-chemical properties of butyl rubber subjected to thermal ageing. Doses used herein were: 25 kGy, 50 kGy, 100 kGy, 150 kGy and 200 KGy. Samples were evaluated before and after ageing according to traditional essays, such as: hardness, tensile strength and elongation at break. From accomplished assessments it is possible to affirm that at doses higher than 50 kGy it was observed a sharp decreasing in butyl rubber physical-chemical properties, before and after exposure to ageing. (author)

Gamma-radiation effect on thermal ageing of butyl rubber compounds

International Nuclear Information System (INIS)

Scagliusi, Sandra R.; Cardoso, Elizabeth C.L.; Lugao, Ademar B.

2015-01-01

Butyl rubber has a comprehensive use in sealing systems, especially in tires inner tubes, due to their low permeability to gases. So, it is required that butyl rubber compounds show a better performance, more and more. Butyl rubber is provided with excellent mechanical properties and oxidation resistance. Besides showing these properties, radiation exposures impart modifications in physical-chemical and morphological properties on butyl rubber materials. When exposed to gamma-radiation, rubbers suffer changes in their mechanical and physical properties, caused by material degradation. The major radiation effect in butyl rubbers is chain scission; besides, ageing promotes too the same effect with further build-up of free radicals. This work aims to the study of gamma-radiation in physical-chemical properties of butyl rubber subjected to thermal ageing. Doses used herein were: 25 kGy, 50 kGy, 100 kGy, 150 kGy and 200 KGy. Samples were evaluated before and after ageing according to traditional essays, such as: hardness, tensile strength and elongation at break. From accomplished assessments it is possible to affirm that at doses higher than 50 kGy it was observed a sharp decreasing in butyl rubber physical-chemical properties, before and after exposure to ageing. (author)

Effects of radiation on health and safety measures

International Nuclear Information System (INIS)

Bansal, J.K.; Chawla, Raman; Sharma, Rakesh Kumar

2007-01-01

The most striking aspect of the effects of ionizing radiation on the living organisms at various levels of organization, is the grave damage produced by relatively trivial amounts of absorbed energy. At the physical level the reason for this lies in the fact that the energy is deposited in concentrated packets along the tracks of the ionizing particles. Injury to living tissue results from the transfer of energy to atoms and molecules in the cellular structure. Ionizing radiation causes atoms and molecules to become ionized or excited. These excitations and ionizations produce free radicals causing breakage of chemical bonds, production of new chemical bonds and cross-linkage between macromolecules and molecules in a critical structure (e.g. DNA, RNA, membrane or other organelle). It initiates in the fraction of seconds from subatomic level eventually effects complete biosphere

Radiation-chemical concepts applied to the wholesomeness evaluation of irradiated foods

International Nuclear Information System (INIS)

Basson, R.A.

1977-06-01

Food irradiation has anomalously been classified as a food additive rather than as a processing method. The justification for this is that chemical changes take place during the process. However, most foodstuffs consist of a large number of constituents, most of which are present in small concentrations. As a result, the amounts of radiolysis products which may be formed are far too low for identification and measurement, even by conventional analytical methods. Radiation-chemical knowledge is applied to determine the probable nature and concentration of reaction products produced in fruits. Fruits consist mainly of water and carbohydrates, with small amounts of protein, fat, inorganic material and vitamins as 'contaminants'. The real situation is exceedingly complex, but, using this simple model as a first approximation, predictions which may be verified in a relatively simple experimental scheme are made on the radiation stability of a typical fruit. Calculations using known radiation-chemical data show that, in the case of the mango, only carbohydrates are present in sufficient concentration and of sufficient sensitivity to merit attention from a toxicological viewpoint. Experimentally, the radiation sensitivity of numerous constituents of the fruit has been compared with that of glucose and, apart from a few exceptions whose concentrations are minimal, results obtained agree well with predicted values [af

Radiation chemical behavior of Rh(III) in HClO4 and HNO3

International Nuclear Information System (INIS)

Vladimirova, M.V.; Khalkina, E.V.

1995-01-01

The radiation chemical behavior of Rh is very interesting since Rh accumulates in irradiated U but has not been reported in the literature. Scattered data do exist for the radiation chemical behavior of Rh(III) in weakly acidic and alkaline solutions. Pulsed radiolysis was used to investigate the formation of unstable oxidation states of Rh during reduction and oxidation of Rh(III) in neutral solutions. The rate constant of the reaction Rh(III) + e aq - was found to be 6·10 10 liter/mole·sec. The radiation chemical behavior of Rh(III) toward γ-radiolysis in neutral, weakly acidic (up to 0.1 N), and alkaline solutions was examined. In neutral solutions of [Rh(NH 3 ) 5 Cl]Cl 2 and RhCl 3 , metallic Rh is formed. The degree of reduction is ∼ 1%. In neutral and weakly acidic solutions of Rh(NO 3 ) 3 , Rh 2 O 3 ·xH 2 O is formed. Irradiation of Rh(ClO 4 ) 3 solutions produces no reduction. The radiation chemical behavior of Rh(III) in HClO 4 and HNO 3 solutions at concentrations > 1 M is studied in the present work

Radiation and man - evaluation of biological and environmental low level radiation effects

International Nuclear Information System (INIS)

Riklis, E.

1977-01-01

The harmful effects of acute radiation cannot be resolved by statistical means and require clearer knowledge of mechanisms of action and much wider collection of human experience before any definite sound stand can be taken. Much information has accumulated from animal experiments, and still the interpretations are not always clearcut, but for human experience it is only the occasional accident which can give a direct answer. Some of the phenomena attributed to low dose radiation are summarized. There are regions of radiation exposure about which we have only limited positive knowledge, an all low-dose risk estimates have been based on effects observed at relatively high doses. Much information has been gathered which does not support the severity of former basic principles, especially our knowledge of mechanisms of repair existing in most cells as natural defence against the damages caused by radiation as well as by many chemicals which act as mutagenic and carcinogenic agents. Understanding these mechanism, their scope of action and their availability to a damaged cell and organism will lead towards modification of the acceptable permissible exposures, in some cases towards severity, but in most cases towards leniency and higher values. For the evaluation of the effects of low level low dose-rate radiations, whether external, or from internal deposition of isotopes, only late somatic and genetic effects should be considered. (B.G.)

Effects of ionizing radiation in ginkgo and guarana

International Nuclear Information System (INIS)

Rabelo Soriani, Renata; Satomi, Lucilia Cristina; Pinto, Terezinha de Jesus A.

2005-01-01

Raw plant materials normally carry high bioburden due to their origin, offering potential hazards to consumers. The use of decontamination processes is therefore an important step towards the consumer safety and therapeutical efficiency. Several authors have reported the treatment of medicinal herbs with ionizing radiation. This work evaluated the effects of different radiation doses on the microbial burden and chemical constituents of ginkgo (Ginkgo biloba L.) and guarana (Paullinia cupana H.B.K.)

Effect of Radiation on Chromospheric Magnetic Reconnection: Reactive and Collisional Multi-fluid Simulations

Energy Technology Data Exchange (ETDEWEB)

Alvarez Laguna, A.; Poedts, S. [Centre for Mathematical Plasma-Astrophysics, KU Leuven, Leuven (Belgium); Lani, A.; Deconinck, H. [Aeronautics and Aerospace Department, von Karman Institute for Fluid Dynamics, Sint-Genesius-Rode (Belgium); Mansour, N. N. [NASA Ames Research Center, MS 230-3, Moffett Field, CA 94035 (United States)

2017-06-20

We study magnetic reconnection under chromospheric conditions in five different ionization levels from 0.5% to 50% using a self-consistent two-fluid (ions + neutrals) model that accounts for compressibility, collisional effects, chemical inequilibrium, and anisotropic heat conduction. Results with and without radiation are compared, using two models for the radiative losses: an optically thin radiation loss function, and an approximation of the radiative losses of a plasma with photospheric abundances. The results without radiation show that reconnection occurs faster for the weakly ionized cases as a result of the effect of ambipolar diffusion and fast recombination. The tearing mode instability appears earlier in the low ionized cases and grows rapidly. We find that radiative losses have a stronger effect than was found in previous results as the cooling changes the plasma pressure and the concentration of ions inside the current sheet. This affects the ambipolar diffusion and the chemical equilibrium, resulting in thin current sheets and enhanced reconnection. The results quantify this complex nonlinear interaction by showing that a strong cooling produces faster reconnections than have been found in models without radiation. The results accounting for radiation show timescales and outflows comparable to spicules and chromospheric jets.

Chemical implications of heat and radiation damage to rock salt

International Nuclear Information System (INIS)

Pederson, L.R.

1984-11-01

Chemical changes induced in Palo Duro and Paradox Basin natural rock salts and in synthetic NaCl by heat and gamma radiation were investigated. Heating of unirradiated natural rock salts to 300 0 C resulted in HCl (most prevalent), SO 2 , CO 2 , and H 2 S evolution, and increased the base content of the remaining salt by not more than 10 microequivalents per gram; whereas, heating of synthetic NaCl gave no product. Gamma irradiation produced sodium colloids and neutral chlorine in amounts similar to the results of Levy and coworkers. When the irradiated salts were heated, three reactions were apparent: (1) radiation-induced defects recombined; (2) neutral chlorine was evolved; and (3) HCl, SO 2 , CO 2 , and H 2 S were evolved, similar to results for unirradiated salts. Because reaction (1) appeared to dominate over reaction (2), it is expected that the influence of radiation damage to salt on the near-field chemical environment will be minor. 4 figures, 1 table

Modification of genetic effects of gamma radiation by laser radiation

International Nuclear Information System (INIS)

Khotyljova, L.V.; Khokhlova, S.A.; Khokhlov, I.V.

1988-01-01

Full text: Mutants obtained by means of ionizing radiation and chemical mutagens often show low viability and productivity that makes their use in plant breeding difficult. Methods reducing the destructive mutagen action on important functions of plant organism and increasing quality and practical value of induced mutants would be interesting. We believe that one method for increasing efficiency of experimental mutagenesis in plants is the application of laser radiation as a modificator of genetic effects of ionizing radiation and chemical mutagens. Combined exposure of wheat seedlings to a gamma radiation dose of 2 kR and to laser radiation with the wave length of 632.8 nm (power density - 20 mVt/cm 2 , exposure - 30 min.) resulted in reducing the chromosomal aberration percentage from 30.5% in the gamma version to 16.3% in the combined treatment version. A radiosensibilizing effect was observed at additional exposure of gamma irradiated wheat seeds to laser light with the wave length of 441.6 nm where chromosomal aberration percentage increased from 22% in the gamma-irradiation version to 31% in the combined treatment version. By laser radiation it is also possible to normalize mitotic cell activity suppressed by gamma irradiation. Additional seedling irradiation with the light of helium-neon laser (632.8 nm) resulted in recovery of mitotic cell activity from 21% to 62% and increasing the average content of DNA per nucleus by 10%. The influence of only laser radiation on plant variability was also studied and it was shown that irradiation of wheat seeds and seedlings with pulsed and continuous laser light of visible spectrum resulted in phenotypically altered forms in M 2 . Their frequencies was dependent upon power density, dose and radiation wave length. Number of altered forms increased in going from long-wave to short-wave spectrum region. In comparing efficiency of different laser types of pulsed and continuous exposure (dose - 180 J/cm 2 ) 2% of altered

Investigation of radiation-chemical behaviour of divalent palladium in perchloric acid solutions

International Nuclear Information System (INIS)

Vladimirova, M.V.; Kalinina, S.V.

1988-01-01

Gamma-radiolysis of divalent palladium in perchloric acid solutions is studied. Absorption spectra of intermediate palladium compounds formed in the irradiated solution are taken. The analysis of literature data as well as comparative analysis of the absorption spectra obtained under irradiation of palladium (2) perchloric acid solutions with absorption spectra of palladium chlorocomplexes allows to suppose that the mentioned compounds are chlorocomplexes of palladium (2) of different composition depending on HClO 4 concentration in the initial solution and absorbed radiation dose. Radiation-chemical reduction of palladium (2) up to metal is stated to take place in the whole studied range of initial concentrations of components of the system and dose rates. Kinetic dependences of metallic palladium formation are obtained. Values of radiation-chemical yields of metallic palladium formation depending on the initial concentrations of palladium (2) and perchloric acid are given. A mechanism of radiolytic reduction of palladium (2) in the investigated system is suggested based on the experimental data, and a theoretical value of the radiation-chemical yield of palladium (2) reduction being in a good agreement with experimentally found values is calculated

Possible preparation of wood-plastic composites based on unsaturated polyester resins and styrene by radiation and chemical methods in combination

International Nuclear Information System (INIS)

Pesek, M.; Pultar, F.; Jarkovsky, J.; Andr, J.

1983-01-01

Using the radiation chemical method it is possible to prepare wood-plastic composites using doses of 1 to 2.5 kGy. The impregnation mixture in the wood gelatinates and subsequent curing using chemical initiators takes place without outflow of the mixture from the wood and without formation of incrustations. The basic components of the impregnation mixtures used were unsaturated polyester resins; styrene or methyl methacrylate was used as the thinner. The proven initiator of polymerization was 2,2'-azobisisobutyronitrile. The technology is described of wood impregnation and radiation or chemical curing. The effects were monitored of viscosity, temperature, radiation dose and the concentrations of the individual components of the impregnation mixtures and initiators of polymerization on the process of the preparation of wood-plastic composites. (M.D.)

Chemical Modifications of Starch: Microwave Effect

OpenAIRE

Lewicka, Kamila; Siemion, Przemysław; Kurcok, Piotr

2015-01-01

This paper presents basic methods of starch chemical modification, the effect of microwave radiation on the modification process, and the physicochemical properties of starch. It has been shown that the modifications contribute to improvement of the material performance and likewise to significant improvement of its mechanical properties. As a result, more and more extensive use of starch is possible in various industries. In addition, methods of oxidized starch and starch esters preparation ...

Mathematical modeling of the radiation-chemical oxidation of U(IV) in HClO4

International Nuclear Information System (INIS)

Vladimirova, M.V.

1995-01-01

Mathematical modeling of U(IV) oxidation in 0.5-12 M HClO 4 upon α, γ-radiolysis, based on the proposed scheme of radiation-chemical reactions, has been performed. The rate constants of the U(VI) + HO 2 , U(IV) + HO 2 , U(IV) + ClO 2 , and U(IV) + ClO 2 - reactions have been determined by the comparison of the calculated and experimental kinetic and dose curves and radiation-chemical yields of U(IV) oxidation or U(VI) formation. General equations for uranium (IV) oxidation constants at various HClO 4 concentrations, based on the analysis of the rates of particular radiation-chemical reactions composing oxidation process, have been obtained

Effects of magnetic, radiation and chemical reaction on unsteady heat and mass transfer flow of an oscillating cylinder

Science.gov (United States)

Ahmed, Rubel; Rana, B. M. Jewel; Ahmmed, S. F.

2017-06-01

The effects of magnetic, radiation and chemical reaction parameters on the unsteady heat and mass transfer boundary layer flow past an oscillating cylinder is considered. The dimensionless momentum, energy and concentration equations are solved numerically by using explicit finite difference method with the help of a computer programming language Compaq visual FORTRAN 6.6a. The obtained results of this study have been discussed for different values of well-known parameters with different time steps. The effect of these parameters on the velocity field, temperature field and concentration field, skin-friction, Nusselt number, streamlines and isotherms has been studied and results are presented by graphically represented by the tabular form quantitatively. The stability and convergence analysis of the solution parameters that have been used in the mathematical model have been tested.

Chemical and physical conversion in cold atmosphere and the effect of radiation

Energy Technology Data Exchange (ETDEWEB)

Kulmala, M; Aalto, P; Korhonen, P; Laaksonen, A; Vesala, T [Helsinki Univ. (Finland). Dept. of Physics

1997-12-31

The project is focusing on the formation and growth mechanisms of atmospheric aerosol and cloud droplets. Both aerosol particles and cloud droplets affect strongly on the atmospheric radiation fluxes by scattering and absorption. The droplet formation results from physical and chemical processes occurring simultaneously. The studies concerning the tropospheric cloud droplet formation, laboratory experiments with a cloud chamber and stratospheric cloud formation are summarized. The recent studies summarized in this presentation indicate that both aerosol particles and cloud droplets have a significant role in climatic change and ozone depletion problems. The anthropogenic emissions of gaseous and particulate pollutants change the properties of atmospheric aerosols and cloud droplets. The research in this field will be continued and more quantitative understanding based both experimental and theoretical studies is required

Chemical and physical conversion in cold atmosphere and the effect of radiation

Energy Technology Data Exchange (ETDEWEB)

Kulmala, M.; Aalto, P.; Korhonen, P.; Laaksonen, A.; Vesala, T. [Helsinki Univ. (Finland). Dept. of Physics

1996-12-31

The project is focusing on the formation and growth mechanisms of atmospheric aerosol and cloud droplets. Both aerosol particles and cloud droplets affect strongly on the atmospheric radiation fluxes by scattering and absorption. The droplet formation results from physical and chemical processes occurring simultaneously. The studies concerning the tropospheric cloud droplet formation, laboratory experiments with a cloud chamber and stratospheric cloud formation are summarized. The recent studies summarized in this presentation indicate that both aerosol particles and cloud droplets have a significant role in climatic change and ozone depletion problems. The anthropogenic emissions of gaseous and particulate pollutants change the properties of atmospheric aerosols and cloud droplets. The research in this field will be continued and more quantitative understanding based both experimental and theoretical studies is required

Effects of radiation rays on construction materials

International Nuclear Information System (INIS)

Akkurt, I.; Kilicarslan, S.; Basyigit, C.; Kacar, A.

2006-01-01

Molecules that are bring into existence material determined as gas, liquid and stiff according to their internal structures and heat. Materials show various reaction to various effects that is result from all kind of materials have various internal structures. Radiation is covert materials' mechanical, physical and chemical properties. Nowadays in construction formation there isn't using only one material it is preferred that kind of materials composition because of there are run into some problems about choosing and decision sort of material. Material that using in construction is classified as metals, plastics and ceramics in three groups. About sixty percent of construction cost is being formed from construction materials. In this study effects of various radiations on construction materials are being investigated and the end of study it is being suggestion some useful construction materials according to usage land and radiation properties

Radiation-chemical degradation of chloroform in water solutions

International Nuclear Information System (INIS)

Ahmadov, S.A.; Gurbanov, M.A.; Iskenderova, Z.I.; Abdullayev, E.T.; Ibadov, N.A.

2006-01-01

Full text: Chloroform is the major chlorine-containing compound forming at chlorination of drinking water. As our basic water resources of Kur and Araz rivers are mostly polluted along the territory of the neighbour republics their chlorination for the purpose of biological purification can result in forming of chloroform. Unfortunately, there are only poor data about containing of chloroform in drinking water in the Republic, however the particular problem is to develop new methods of drinking water purification from chloroform, taking into account the high toxicity of this compounds. Appropriate works indicate that radiation-chemical processing can mostly reduce the concentration of chloroform in drinking water. The purification degree can achieve 95-98 percent. This work studies the tendency of chloroform decomposition at its radiolysis processes in water solutions. The concentration of chloroform changed in the range of 0,03-1 weight percentage. Taking into account the dissolvability of chloroform in water solutions it can be said that examined water solutions are homogeneous. Following advancements are studied: 1) Determination of radiation-chemical yield of chloroform decomposition at its various initial concentrations; 2) Impact of adsorbed dose on pH of solutions; 3) Formation of by-products. It is set that radiation-chemical output of chloroform decomposition is equal to 3 * 10 - 3 - 125 mol/100 ev. The high yield of chloroform decomposition can be connected with the chain process of oxidation with presence of dissolved oxygen. However, taking into account the fact that at its water radiolysis the yield of active particles of OH, e - aq, H-atoms does not exceed 6-7 particles/100 ev, the observed high yield can be explained only with the chain process with presence of dissolved oxygen

Effect of radiation resistance additives for insulation materials

International Nuclear Information System (INIS)

Yamamoto, Yasuaki; Yagyu, Hideki; Seguchi, Tadao.

1988-01-01

For the electric wires and cables used in radiation environment such as nuclear power stations and fuel reprocessing facilities, the properties of excellent radiation resistance are required. For these insulators and sheath materials, ethylene propylene rubber, polyethylene and other polymers have been used, but it cannot be said that they always have good radiation resistance. However, it has been well known that radiation resistance can be improved with small amount of additives, and heat resistance and burning retarding property as well as radiation resistance are given to the insulators of wires and cables for nuclear facilities by mixing various additives. In this research, the measuring method for quantitatively determining the effect of Anti-rad (radiation resistant additive) was examined. Through the measurement of gel fraction, radical formation and decomposed gas generation, the effect of Anti-rad protecting polymers from radiation deterioration was examined from the viewpoint of chemical reaction. The experimental method and the results are reported. The radiation energy for cutting C-H coupling is polymers is dispersed by Anti-rad, and the probability of cutting is lowered. Anti-rad catches and extinguishes radicals that start oxidation reaction. (K.I.)

Comparison of the concepts used to develop and apply occupational exposure limits for ionizing radiation and hazardous chemical substances

International Nuclear Information System (INIS)

Halton, D.M.

1988-01-01

The rationales used by the American Conference of Governmental Industrial Hygienists (AC-GIH) to recommend exposure limits for 10 chemicals were reviewed. The 10 chemicals chosen were known to produce chronic disease after prolonged overexposure in the workplace. The chemicals were toluene diisocyanate, hydrogen fluoride, n-hexane, carbon disulfide, cadmium, inorganic mercury, cobalt, nitroglycerol, silica, and vinyl chloride. The rationales used by the International Commission on Radiological Protection (ICRP) to recommend limits for workplace exposure to ionizing radiation were reviewed. The rationales used in occupational health by ACGIH were then compared with those used by ICRP in health physics. The comparison revealed a significant divergence in the underlying concepts and philosophies of the two approaches. This divergence cannot be solely attributed to differences in scientific knowledge about toxicological and radiological effects. In areas of scientific uncertainty, exposure limits for ionizing radiation are based on worst case or conservative assumptions. This approach favors human safety. Parallel approaches could not be found for any of the 10 chemicals reviewed. Other factors such as the costs incurred by industry in meeting the proposed standards played a more significant role in establishing limits for workplace chemicals than for ionizing radiation

Radiation-chemical behaviour of Rh(4) in perchlorate and nitrate solutions

International Nuclear Information System (INIS)

Vladimirova, M.V.; Khalkina, E.V.

1994-01-01

Kinetic of rhodium(4) reduction in the process of radiolysis in solutions of perchloric (0.6-3.2 mol/l) and nitric (2-9 mol/l) acids with rhodium (4) concentration (0.4-5)x10 -3 mol/l has been studied. Irradiation of the solutions was carried out using a 60 Co source with dose rate of 3.5 Gy/s in the absorbed dose range up to 10 4 Gy. A mechanism of radiation-chemical reduction of rhodium(4) in perchloric and nitric acid solutions in suggested, the reason for high radiation-chemical yields of reduction is discussed. 7 refs.; 9 figs.; 2 tabs

Effect of gamma radiation on the resistance of Staphylococcus aureus (Rosembach, 1884) and in the physical-chemical and sensory properties of 'minas frescal' cheese

International Nuclear Information System (INIS)

Gurgel, Maria Sylvia de Campos Carvalho do Amaral

2000-01-01

Among food poisoning of microbial origin, S. aureus stands as one of the most important, being a pathogenic bacteria for as human kind and of important occurrence in food products. Although 'Minas Frescal' cheese is typically Brazilian, there aren't in this country technical rules for its preparation and appropriate inspection. In the present work the effect of gamma radiation on the resistance of S. aureus and its ability to produce toxins in 'Minas Frescal' cheese were evaluated. The effects of the radiation in 'Minas Frescal' cheese physical-chemical and sensory properties will be determined, with the objective of studying the efficiency of the gamma radiation as method of conservation of this product. During the fabrication of 'Minas Frescal' cheese in the Laboratory of Irradiation of Foods (CENA/USP), S. aureus strains (ATCC 13565, ATCC 14458, ATCC 19095) with approximate count of 106 UFC/ml were inoculated. After irradiation with doses of O(control); 1; 2; 3 and 4 kGy, the cheeses were stored under refrigeration (+- 5 deg C) and analyzed at 1, 7 and 14 days. After irradiation with doses of O(control); 1; 2; 3 and 4 kGy, the cheeses were stored under refrigeration (+- 5 deg C) and analyzed at 1,7 and 14 days. 'Minas Frescal' cheese was evaluated through the determination of parameters of acidity, pH, moisture and lever of extension proteolysis, according to methodology of Association of Official Analytical Chemists (AO.AC.),1995, and sensory analysis by the ADQ (Quantitative Descriptive Analysis) method. The microbiological analysis determined the survival of S. aureus in the Baird-Parker a selective medium and its ability of producing enterotoxin by the Passive Reverse Agglutination with Latex method. the results analyzed through randomized blocks in a factorial design (5x3), revealed that 'Minas Frescal' cheese did not present significant differences among the radiation doses in relation to its physical-chemical and sensory properties. Dose of 3 kGy was

Environmental chemical mutagens and genetic risks: Lessons from radiation genetics

International Nuclear Information System (INIS)

Sankaranarayanan, K.

1996-01-01

The last three decades have witnessed substantial progress in the development and use of a variety of in vitro and in vivo assay systems for the testing of environmental chemicals which may pose a mutagenic hazard to humans. This is also true of basic studies in chemical mutagenesis on mechanisms, DNA repair, molecular dosimetry, structure-activity relationships, etc. However, the field of quantitative evaluation of genetic risks of environmental chemicals to humans is still in it infancy. This commentary addresses the question of how our experience in estimating genetic risks of exposure to ionizing radiation can be helpful in similar endeavors with environmental chemical mutagens. 24 refs., 3 tabs

Radiation preservation of maize

International Nuclear Information System (INIS)

Wasito.

1980-01-01

Radiation preservation of maize was carried out. Radiation doses and sources, shielding materials, packaging materials, chemical radiation effects, biological radiation effects, were discussed. Experimental methods, samples and accessories were also presented. (SMN)

Low environmental radiation background impairs biological defence of the yeast Saccharomyces cerevisiae to chemical radiomimetic agents

International Nuclear Information System (INIS)

Satta, L.; Augusti-Tocco, G.; Ceccarelli, R.; Paggi, P.; Scarsella, G.; Esposito, A.; Fiore, M.; Poggesi, I.; Ricordy, R.; Cundari, E.

1995-01-01

Background radiation is likely to constitute one of the factors involved in biological evolution since radiations are able to affect biological processes. Therefore, it is possible to hypothesize that organisms are adapted to environmental background radiation and that this adaptation could increase their ability to respond to the harmful effects of ionizing radiations. In fact, adaptive responses to alkylating agents and to low doses of ionizing radiation have been found in many organisms. In order to test for effects of adaptation, cell susceptibility to treatments with high doses of radiomimetic chemical agents has been studied by growing them in a reduced environmental radiation background. The experiment has been performed by culturing yeast cells (Saccharomyces cerevisiae D7) in parallel in a standard background environment and in the underground Gran Sasso National Laboratory, with reduced environmental background radiation. After a conditioning period, yeast cells were exposed to recombinogenic doses of methyl methanesulfonate. The yeast cells grown in the Gran Sasso Laboratory showed a higher frequency of radiomimetic induced recombination as compared to those grown in the standard environment. This suggests that environmental radiation may act as a conditioning agent

Physico-chemical evaluation of radiation effects on apple juice

International Nuclear Information System (INIS)

Blumer, Lucimara; Domarco, Rachel E.; Spoto, Maria H.F.; Walder, Julio M.M.; Matraia, Clarice

1997-01-01

Gala and Fuji varieties apple's juice were clarified with enzyme and irradiated aiming to extend the shelf-life without conservants and chemical additives. The juices were analysed for soluble solids, titrable acidity, pH and color. Results showed effect of storage periods in soluble solids, pH and color. The variety and storage period modified the titrable acidity. The pH was altered by irradiation dose and the storage period. (author). 9 refs., 6 figs

Aerosol direct radiative effects over the northwest Atlantic, northwest Pacific, and North Indian Oceans: estimates based on in-situ chemical and optical measurements and chemical transport modeling

Directory of Open Access Journals (Sweden)

T. S. Bates

2006-01-01

Full Text Available The largest uncertainty in the radiative forcing of climate change over the industrial era is that due to aerosols, a substantial fraction of which is the uncertainty associated with scattering and absorption of shortwave (solar radiation by anthropogenic aerosols in cloud-free conditions (IPCC, 2001. Quantifying and reducing the uncertainty in aerosol influences on climate is critical to understanding climate change over the industrial period and to improving predictions of future climate change for assumed emission scenarios. Measurements of aerosol properties during major field campaigns in several regions of the globe during the past decade are contributing to an enhanced understanding of atmospheric aerosols and their effects on light scattering and climate. The present study, which focuses on three regions downwind of major urban/population centers (North Indian Ocean (NIO during INDOEX, the Northwest Pacific Ocean (NWP during ACE-Asia, and the Northwest Atlantic Ocean (NWA during ICARTT, incorporates understanding gained from field observations of aerosol distributions and properties into calculations of perturbations in radiative fluxes due to these aerosols. This study evaluates the current state of observations and of two chemical transport models (STEM and MOZART. Measurements of burdens, extinction optical depth (AOD, and direct radiative effect of aerosols (DRE – change in radiative flux due to total aerosols are used as measurement-model check points to assess uncertainties. In-situ measured and remotely sensed aerosol properties for each region (mixing state, mass scattering efficiency, single scattering albedo, and angular scattering properties and their dependences on relative humidity are used as input parameters to two radiative transfer models (GFDL and University of Michigan to constrain estimates of aerosol radiative effects, with uncertainties in each step propagated through the analysis. Constraining the radiative

Chemical applications of synchrotron radiation: Workshop report

International Nuclear Information System (INIS)

1989-04-01

The most recent in a series of topical meetings for Advanced Photon Source user subgroups, the Workshop on Chemical Applications of Synchrotron Radiation (held at Argonne National Laboratory, October 3-4, 1988) dealt with surfaces and kinetics, spectroscopy, small-angle scattering, diffraction, and topography and imaging. The primary objectives were to provide an educational resource for the chemistry community on the scientific research being conducted at existing synchrotron sources and to indicate some of the unique opportunities that will be made available with the Advanced Photon Source. The workshop organizers were also interested in gauging the interest of chemists in the field of synchrotron radiation. Interest expressed at the meeting has led to initial steps toward formation of a Chemistry Users Group at the APS. Individual projects are processed separately for the data bases

Chemical applications of synchrotron radiation: Workshop report

Energy Technology Data Exchange (ETDEWEB)

1989-04-01

The most recent in a series of topical meetings for Advanced Photon Source user subgroups, the Workshop on Chemical Applications of Synchrotron Radiation (held at Argonne National Laboratory, October 3-4, 1988) dealt with surfaces and kinetics, spectroscopy, small-angle scattering, diffraction, and topography and imaging. The primary objectives were to provide an educational resource for the chemistry community on the scientific research being conducted at existing synchrotron sources and to indicate some of the unique opportunities that will be made available with the Advanced Photon Source. The workshop organizers were also interested in gauging the interest of chemists in the field of synchrotron radiation. Interest expressed at the meeting has led to initial steps toward formation of a Chemistry Users Group at the APS. Individual projects are processed separately for the data bases.

Mechanisms of chemical modification of neoplastic cell transformation by ionizing radiation

International Nuclear Information System (INIS)

Yang, T.C.; Tobias, C.A.

1985-01-01

During space travel, astronauts will be continuously exposed to ionizing radiation; therefore, it is necessary to minimize the radiation damage by all possible means. The authors' studies show that DMSO (when present during irradiation) can protect cells from being killed and transformed by X rays and that low concentration of DMSO can reduce the transformation frequency significantly when it is applied to cells, even many days after irradiation. The process of neoplastic cell transformation is a complicated one and includes at least two different stages: induction and expression. DMSO apparently can modify the radiation damage during both stages. There are several possible mechanisms for the DMSO effect: (1) changing the cell membrane structure and properties; (2) inducing cell differentiation by acting on DNA; and (3) scavanging free radicals in the cell. Recent studies with various chemical agents, e.g., 5-azacytidine, dexamethane, rhodamin-123, etc., indicate that the induction of cell differentiation by acting on DNA may be an important mechanism for the suppression of expression of neoplastic cell transformation by DMSO

U.S. Department of Energy Workers' mental models of radiation and chemical hazards in the workplace

International Nuclear Information System (INIS)

Quadrel, M.J.; Blanchard, K.A.; Lundgren, R.E.; McMakin, A.H.; Mosley, M.T.; Strom, D.J.

1994-05-01

A pilot study was performed to test the mental models methodology regarding knowledge and perceptions of U.S. Department of Energy contractor radiation workers about ionizing radiation and hazardous chemicals. The mental models methodology establishes a target population's beliefs about risks and compares them with current scientific knowledge. The ultimate intent is to develop risk communication guidelines that address information gaps or misperceptions that could affect decisions and behavior. In this study, 15 radiation workers from the Hanford Site in Washington State were interviewed about radiation exposure processes and effects. Their beliefs were mapped onto a science model of the same topics to see where differences occurred. In general, workers' mental models covered many of the high-level parts of the science model but did not have the same level of detail. The following concepts appeared to be well understood by most interviewees: types, form, and properties of workplace radiation; administrative and physical controls to reduce radiation exposure risk; and the relationship of dose and effects. However, several concepts were rarely mentioned by most interviewees, indicating potential gaps in worker understanding. Most workers did not discuss the wide range of measures for neutralizing or decontaminating individuals following internal contamination. Few noted specific ways of measuring dose or factors that affect dose. Few mentioned the range of possible effects, including genetic effects, birth defects, or high dose effects. Variables that influence potential effects were rarely discussed. Workers rarely mentioned how basic radiation principles influenced the source, type, or mitigation of radiation risk in the workplace

Health Effects of Exposure to Low Dose of Radiation

International Nuclear Information System (INIS)

Alatas, Zubaidah

2003-01-01

Human beings are exposed to natural radiation from external sources include radionuclides in the earth and cosmic radiation, and by internal radiation from radionuclides, mainly uranium and thorium series, incorporated into the body. Living systems have adapted to the natural levels of radiation and radioactivity. But some industrial practices involving natural resources enhance these radionuclides to a degree that they may pose risk to humans and the environment if they are not controlled. Biological effects of ionizing radiation are the outcomes of physical and chemical processes that occur immediately after the exposure, then followed by biological process in the body. These processes will involve successive changes in the molecular, cellular, tissue and whole organism levels. Any dose of radiation, no matter how small, may produce health effects since even a single ionizing event can result in DNA damage. The damage to DNA in the nucleus is considered to be the main initiating event by which radiation causes damage to cells that results in the development of cancer and hereditary disease. It has also been indicated that cytogenetic damage can occur in cells that receive no direct radiation exposure, known as bystander effects. This paper reviews health risks of low dose radiation exposure to human body causing stochastic effects, i.e. cancer induction in somatic cells and hereditary disease in genetic cells. (author)

Radiation-chemical sanitation of dissolved pollutants and environmental protection

International Nuclear Information System (INIS)

Petrukhin, N.V.; Putilov, A.V.

1986-01-01

Radiation-chemical sanitation of dissolved toxic pollutants resulted from the production processes of different substances and modern equipment operation is considered. The processes of fundamental industrial sewage processing and, as a result, features of practically total disposal of dissolved toxic agents are considered for the first time

Chemical structure and radiation stability of solid crystalline antibiotics: thiamphenicol and chloramphenicol

International Nuclear Information System (INIS)

Varshney, Lalit; Soe Nwe

1997-01-01

Antibiotics in solid state show significant radiation resistance and some of them are exposed to gamma or electron beam irradiation for sterilization. Even small radiation degradation in solid state antibiotics is not desirable. Two antibiotics namely thiamphenicol (TPL) and chloramphenicol (CPL) having similar chemical and solid state structure were irradiated at different graded radiation doses to study their stability. Differential scanning calorimetry (DSC) was used to evaluate purity, entropy of radiation processing, heat of fusion and melting point. (author). 3 refs., 1 tab

Report on NCI symposium: comparison of mechanisms of carcinogenesis by radiation and chemical agents. II. Cellular and animal models

International Nuclear Information System (INIS)

Fry, R.J.M.

1984-01-01

The point at which the common final pathway for induction of cancer by chemical carcinogens and ionizing radiation has not been identified. Although common molecular targets are suggested by recent findings about the role of oncogenes, the mechanism by which the deposition of radiation energy and the formation of adducts or other DNA lesions induced by chemicals affects the changes in the relevant targets may be quite different. The damage to DNA that plays no part in the transformation events, but that influences the stability of the genome, and therefore, the probability of subsequent changes that influence tumorigenesis may be more readily induced by some agents than others. Similarly, the degree of cytotoxic effects that disrupt tissue integrity and increase the probability of expression of initiated cells may be dependent on the type of carcinogen. Also, evidence was presented that repair of the initial lesions could be demonstrated after exposure to low-LET radiation but not after exposure to chemical carcinogens

Report on NCI symposium: comparison of mechanisms of carcinogenesis by radiation and chemical agents. II. Cellular and animal models

Energy Technology Data Exchange (ETDEWEB)

Fry, R.J.M.

1984-01-01

The point at which the common final pathway for induction of cancer by chemical carcinogens and ionizing radiation has not been identified. Although common molecular targets are suggested by recent findings about the role of oncogenes, the mechanism by which the deposition of radiation energy and the formation of adducts or other DNA lesions induced by chemicals affects the changes in the relevant targets may be quite different. The damage to DNA that plays no part in the transformation events, but that influences the stability of the genome, and therefore, the probability of subsequent changes that influence tumorigenesis may be more readily induced by some agents than others. Similarly, the degree of cytotoxic effects that disrupt tissue integrity and increase the probability of expression of initiated cells may be dependent on the type of carcinogen. Also, evidence was presented that repair of the initial lesions could be demonstrated after exposure to low-LET radiation but not after exposure to chemical carcinogens.

Radioprotection effects of TMG to radical scavenger effect of the mice in radiation

International Nuclear Information System (INIS)

Gu, Yeunhwa; Hasegawa, Takeo; Oshima, Masami

2002-01-01

Now there is many it, and the radiotherapy that is one of cancer therapy is used by single or anticancer drug and combination. A chemical material has been used as radioprotector, but the use is limited conventionally by a serious side effect. Vitamin E derivative[TMG 2- (α - D-Glucopyranosyl) Methyl-2,5,7,8-Teramethyl -chorman-6-OL] which we are water-soluble, And is the nature material as well for the fetal teratogenicity that I use ICR mouse used for a malformed experiment frequently in this study, and sensibility for radiation is the highest, we studied radiation protection effect of TMG. As a result, as for the fetal malformed incidence, it was admitted that it fell in shifts and changes by administering TMG before radiation exposure. Decrease depression of degradation of a skeletal malformation rate in particular and fetal weight was recognized, and an individual level made radiation protection indication of TMG clear. In addition, that there was radioprotection effect for embryonic death by radiation was made clear by premedication doing TMG equally, and that there was protection effect for radiation exposure in a cell level same as an individual level was proved, and TMG showed the potency that it was it in radioprotector promising in the future. Furthermore, by what we reviewed about congenital defect for radiation, effect for skeletal malformation incidence and sensibility of embryonic cell level in organogenesis, we analyzed mechanism of protection effect of TMG for fetal teratogenicity by radiation experimentally

Radioprotection effects of TMG to radical scavenger effect of the mice in radiation

Energy Technology Data Exchange (ETDEWEB)

Gu, Yeunhwa; Hasegawa, Takeo; Oshima, Masami [Suzuka Univ. of Medical Science, Suzuka (Japan)] [and others

2002-07-01

Now there is many it, and the radiotherapy that is one of cancer therapy is used by single or anticancer drug and combination. A chemical material has been used as radioprotector, but the use is limited conventionally by a serious side effect. Vitamin E derivative[TMG 2- ({alpha} - D-Glucopyranosyl) Methyl-2,5,7,8-Teramethyl -chorman-6-OL] which we are water-soluble, And is the nature material as well for the fetal teratogenicity that I use ICR mouse used for a malformed experiment frequently in this study, and sensibility for radiation is the highest, we studied radiation protection effect of TMG. As a result, as for the fetal malformed incidence, it was admitted that it fell in shifts and changes by administering TMG before radiation exposure. Decrease depression of degradation of a skeletal malformation rate in particular and fetal weight was recognized, and an individual level made radiation protection indication of TMG clear. In addition, that there was radioprotection effect for embryonic death by radiation was made clear by premedication doing TMG equally, and that there was protection effect for radiation exposure in a cell level same as an individual level was proved, and TMG showed the potency that it was it in radioprotector promising in the future. Furthermore, by what we reviewed about congenital defect for radiation, effect for skeletal malformation incidence and sensibility of embryonic cell level in organogenesis, we analyzed mechanism of protection effect of TMG for fetal teratogenicity by radiation experimentally.

Preparation of polymeric biomaterials with the aid of radiation-chemical methods

International Nuclear Information System (INIS)

Kabanov, Vitalii Ya

1998-01-01

The results of the application of radiation-chemical methods for the preparation of polymeric biomaterials are surveyed and treated systematically. The characteristic features of these methods and their advantages and disadvantages are indicated. The properties of polymeric biomaterials prepared using ionising radiation are examined. Particular attention is devoted to studies carried out during the last 10-15 years. The bibliography includes 492 references.

Estimation of Radiative Efficiency of Chemicals with Potentially Significant Global Warming Potential.

Science.gov (United States)

Betowski, Don; Bevington, Charles; Allison, Thomas C

2016-01-19

Halogenated chemical substances are used in a broad array of applications, and new chemical substances are continually being developed and introduced into commerce. While recent research has considerably increased our understanding of the global warming potentials (GWPs) of multiple individual chemical substances, this research inevitably lags behind the development of new chemical substances. There are currently over 200 substances known to have high GWP. Evaluation of schemes to estimate radiative efficiency (RE) based on computational chemistry are useful where no measured IR spectrum is available. This study assesses the reliability of values of RE calculated using computational chemistry techniques for 235 chemical substances against the best available values. Computed vibrational frequency data is used to estimate RE values using several Pinnock-type models, and reasonable agreement with reported values is found. Significant improvement is obtained through scaling of both vibrational frequencies and intensities. The effect of varying the computational method and basis set used to calculate the frequency data is discussed. It is found that the vibrational intensities have a strong dependence on basis set and are largely responsible for differences in computed RE values.

Genetic effects of ionizing radiation and repair processes

International Nuclear Information System (INIS)

Tuschl, H.

1986-11-01

Since DNA (=desoxyribonucleic acid) is the largest molecule within the cell it is the most important target for direct and indirect radiation effects. Within DNA the total genetic information is stored, thus damage to DNA in germ cells causes genetic disorders and damage in somatic cells is implicated in cancer and immunodeficiences. Alterations of DNA structure are not only due to ionizing radiation effects, but also to spontaneous DNA modifications and damage from interactions with environmental ultraviolet light and chemical agents. To maintain its genetic integrity, each organism had to develop different repair systems able to recognize and remove DNA damage. Repeated exposure to a DNA damaging agent can even lead to adaptation processes and increased resistance to the same agent. At normal function of repair systems it can be assumed that the capacity of those systems is adequate to scope with the effects of low radiation doses. (Author)

Effects of UV-B radiation on wax biosynthesis

International Nuclear Information System (INIS)

Barnes, J.; Paul, N.; Percy, K.; Broadbent, P.; McLaughlin, C.; Mullineaux, P.; Creissen, G.; Wellburn, A.

1994-01-01

Two genotypes of tobacco (Nicotiana tabacum L.) were exposed in controlled environment chambers to three levels of biologically effective ultraviolet-B radiation (UV-B BE ; 280-320nm): 0, 4.54 (ambient) and 5.66 (∼ 25% enhancement) kJ m -2 d -1 . After 28 days, the quantity of wax deposited on leaf surfaces was determined gravimetrically; epicuticular wax chemical composition was determined by capillary gas chromatography with homologue assignments confirmed by gas chromatography-mass spectrometry. Leaf wettability was assessed by measuring the contact angle of water droplets placed on leaf surfaces. Tobacco wax consisted of three major hydrocarbon classes: Straight-chain alkanes (C 27 -C 33 ) which comprised ∼ 59% of the hydrocarbon fraction, containing a predominance of odd-chain alkanes with C 31 as the most abundant homologue; branched-chain alkanes (C 25 -C 32 ) which comprised ∼38% of the hydrocarbon fraction with anteiso 3-methyltriacontane (C 30 ) as the predominant homologue; and fatty acids (C 14 -C 18 ) which comprised ∼ 3% of the wax. Exposure to enhanced UV-B radiation reduced the quantity of wax on the adaxial surface of the transgenic mutant, and resulted in marked changes in the chemical composition of the wax on the exposed leaf surface. Enhanced UV-B decreased the quantity of straight-chain alkanes, increased the quantity of branched-chain alkanes and fatty acids, and resulted in shifts toward shorter straight-chain lengths. Furthermore, UV-B-induced changes in wax composition were associated with increased wettability of tobacco leaf surfaces. Overall, the data are consistent with the view that UV-B radiation has a direct and fundamental effect on wax biosynthesis. Relationships between the physico-chemical nature of the leaf surface and sensitivity to UV-B radiation are discussed. (orig.)

Gamma radiation effects on polydimethylsiloxane rubber foams under different radiation conditions

Science.gov (United States)

Sui, H. L.; Liu, X. Y.; Zhong, F. C.; Li, X. Y.; Wang, L.; Ju, X.

2013-07-01

Polydimethylsiloxane rubber foams were irradiated by gamma ray under different radiation conditions designed by orthogonal design method. Compression set measurement, infrared attenuated total reflectance spectroscopy (ATR) and X-ray induced photoelectron spectroscopy (XPS) were used. Three aging factors' influence effects on the mechanical property and chemical structure were studied. It was found that among the three factors and the chosen levels, both properties were affected most by radiation dose, while radiation dose rate had no obvious influence on both properties. The stiffening of the rubber foams was caused by cross-linking reactions in the Si-CH3. At the same radiation dose, the rigidity of the foams irradiated in air was lower than that in nitrogen. When polydimethylsiloxane was irradiated at a high dose in sealed nitrogen atmosphere, carbon element distribution would be changed. Hydrocarbons produced by gamma ray in the sealed tube would make the carbon content in the skin-deep higher than that in the middle, which indicated that polydimethylsiloxane rubber foams storing in a sealed atmosphere filled with enough hydrocarbons should be helpful to extend the service life.

Gamma radiation effects on polydimethylsiloxane rubber foams under different radiation conditions

Energy Technology Data Exchange (ETDEWEB)

Sui, H.L. [Department of Physics, University of Science and Technology Beijing, Beijing 100083 (China); Institute of Chemical Materials, CAEP, Mianyang 621900 (China); Liu, X.Y.; Zhong, F.C. [Institute of Chemical Materials, CAEP, Mianyang 621900 (China); Li, X.Y. [Institute of Nuclear Physics and Chemistry, CAEP, Mianyang 621900 (China); Wang, L. [Institute of Chemical Materials, CAEP, Mianyang 621900 (China); Ju, X., E-mail: jux@ustb.edu.cn [Department of Physics, University of Science and Technology Beijing, Beijing 100083 (China)

2013-07-15

Polydimethylsiloxane rubber foams were irradiated by gamma ray under different radiation conditions designed by orthogonal design method. Compression set measurement, infrared attenuated total reflectance spectroscopy (ATR) and X-ray induced photoelectron spectroscopy (XPS) were used. Three aging factors’ influence effects on the mechanical property and chemical structure were studied. It was found that among the three factors and the chosen levels, both properties were affected most by radiation dose, while radiation dose rate had no obvious influence on both properties. The stiffening of the rubber foams was caused by cross-linking reactions in the Si–CH{sub 3}. At the same radiation dose, the rigidity of the foams irradiated in air was lower than that in nitrogen. When polydimethylsiloxane was irradiated at a high dose in sealed nitrogen atmosphere, carbon element distribution would be changed. Hydrocarbons produced by gamma ray in the sealed tube would make the carbon content in the skin-deep higher than that in the middle, which indicated that polydimethylsiloxane rubber foams storing in a sealed atmosphere filled with enough hydrocarbons should be helpful to extend the service life.

Biomarkers of DNA and cytogenetic damages induced by environmental chemicals or radiation

International Nuclear Information System (INIS)

1999-01-01

This paper presents and discusses results from the studies on various biomarkers of the DNA and cytogenetic damages induced by environmental chemicals or radiation. Results of the biomonitoring studies have shown that particularly in the condition of Poland, health hazard from radiation exposure is overestimated in contradistinction to the environmental hazard

Contribution of chemical radiation research to the general theory of oxidation of organic substances

International Nuclear Information System (INIS)

Ladygin, B.Ya.; Saraev, V.V.; Revin, A.A.; Zimina, G.M.

1996-01-01

Paper studies mechanisms and main elementary stages of liquid-phase oxidation of organic compounds at thermal and radiation initiation of this reaction. The results of investigations into radiation and chemical conversion of organic compounds at presence of oxygen and without it are discussed on the ground of data obtained by means of pulse radiolysis and EPR-spectroscopy. The bach-Engler theory of slow oxidation of organic compounds with participation of peroxides used as intermediate compounds is shown to be proved essentially and to enjoy further development due to the conducted radiation and chemical investigations. 68 refs., 2 figs., 4 tabs

Chemical films and monolayers on the water surface and their interactions with ultraviolet radiation: a pilot investigation

International Nuclear Information System (INIS)

Schouten, Peter; Lemckert, Charles; Underhill, Ian; Turner, Geoff; Turnbull, David; Parisi, Alfio; Downs, Nathan

2011-01-01

Over the past 50 years numerous types of chemical films and monolayers have been deployed on top of a wide variety of water reserves in an endeavour to reduce evaporation. To date very little knowledge has been assimilated on how these chemical films and monolayers, once applied to a water surface, influence the underwater UV light field and, in turn, the delicate ecosystems that exist in aquatic environments. This manuscript presents underwater UV exposure profiles weighted to the DNA damage action spectrum measured under an octadecanol/hexadecanol/lime chemical film mixture, a silicone-based chemical film and an octadecanol monolayer applied to the water surface. UV transmission and absorption properties were also evaluated for each of these chemical films and monolayers. From this it was found that when chemical films/monolayers are applied to surface water they can reduce the penetration of biologically effective UV into the water column by up to 85% at a depth as small as 1 cm. This could have a positive influence on the aquatic ecosystem, as harmful UV radiation may be prevented from reaching and consequently damaging a variety of life forms or it could have a negative effect by potentially stopping aquatic organisms from adapting to solar ultraviolet radiation over extended application intervals. Additionally, there is currently no readily applicable system or technique available to readily detect or visualize chemical films and monolayers on the water surface. To overcome this problem a new method of monolayer and chemical film visualization, using a UV camera system, is detailed and tested and its applicability for usage in both laboratory-based trials and real-world operations is evaluated

Chemical films and monolayers on the water surface and their interactions with ultraviolet radiation: a pilot investigation

Science.gov (United States)

Schouten, Peter; Lemckert, Charles; Turnbull, David; Parisi, Alfio; Downs, Nathan; Underhill, Ian; Turner, Geoff

2011-06-01

Over the past 50 years numerous types of chemical films and monolayers have been deployed on top of a wide variety of water reserves in an endeavour to reduce evaporation. To date very little knowledge has been assimilated on how these chemical films and monolayers, once applied to a water surface, influence the underwater UV light field and, in turn, the delicate ecosystems that exist in aquatic environments. This manuscript presents underwater UV exposure profiles weighted to the DNA damage action spectrum measured under an octadecanol/hexadecanol/lime chemical film mixture, a silicone-based chemical film and an octadecanol monolayer applied to the water surface. UV transmission and absorption properties were also evaluated for each of these chemical films and monolayers. From this it was found that when chemical films/monolayers are applied to surface water they can reduce the penetration of biologically effective UV into the water column by up to 85% at a depth as small as 1 cm. This could have a positive influence on the aquatic ecosystem, as harmful UV radiation may be prevented from reaching and consequently damaging a variety of life forms or it could have a negative effect by potentially stopping aquatic organisms from adapting to solar ultraviolet radiation over extended application intervals. Additionally, there is currently no readily applicable system or technique available to readily detect or visualize chemical films and monolayers on the water surface. To overcome this problem a new method of monolayer and chemical film visualization, using a UV camera system, is detailed and tested and its applicability for usage in both laboratory-based trials and real-world operations is evaluated.

Effects of chemical reaction in thermal and mass diffusion of micropolar fluid saturated in porous regime with radiation and ohmic heating

Directory of Open Access Journals (Sweden)

Kumar Hitesh

2016-01-01

Full Text Available The present paper analyzes the chemically reacting free convection MHD micropolar flow, heat and mass transfer in porous medium past an infinite vertical plate with radiation and viscous dissipation. The non-linear coupled partial differential equations are solved numerically using an implicit finite difference scheme known as Keller-box method. The results for concentration, transverse velocity, angular velocity and temperature are obtained and effects of various parameters on these functions are presented graphically. The numerical discussion with physical interpretations for the influence of various parameters also presented.

Effects of radiation treatment on foodstuffs

International Nuclear Information System (INIS)

Dehne, L.; Boegl, W.

1980-01-01

The purpose of this study is to discuss and compile methods and results of irradiation experiments carried out on 54 plant and animal foodstuffs in order to obtain a survey on chemical changes, in particular as regards the reduction of nutritional value and savoriness of irradiated foodstuffs. According to this task, microbiological aspects as well as an interpretation of the experimental results as to the physiology of nutrition and toxicology were not included. The results published by the authors of the original papers were compiled in a kind of dictionary which contains all relevant information such as radiation sources, irradiation conditions, investigation methods, results of chemical or organoleptical changes etc. The most important results were summarized in tables and can be found at the end of this study. Because of the abundance of existing literature the series 'Effects of radiation treatment on foodstuffs' will be continued in Part IV, and the final discussion of the results will be published separately after further data have been included. (orig.) [de

Safe storage of premature maize ears through gamma radiation and irradiation effect on chemical composition

International Nuclear Information System (INIS)

Gupta, H.O.; Singh, N.N.; Roy, M.K.

2003-01-01

Marked differences were observed between unirradiated and irradiated premature ears (early dough stage) of maize during storage. Some molds were developed on the grains and deterioration set in at the peduncle and stone of maize in the unirradiated ears, whereas no such symptoms were observed in the 3 kGy irradiated ears even after 45 days of storage. Changes in chemical constituents viz. starch, protein, total sugars were observed in the ears without adversely affecting the quality traits through radiation although 100 grains weight reduced slightly. (author)

Radiation chemical studies on the treatment of waste water

International Nuclear Information System (INIS)

Sakumoto, Akihisa; Miyata, Teijiro; Arai, Michimasa; Arai, Hidehiko

1982-10-01

The radiation induced reaction in aqueous solution was studied to develope the radiation treatment as a new technique for waste water and to elevate the effectiveness of radiation. The effectiveness of radiation was enhanced by combination of radiation induced reaction with conventional methods such as biological treatment and coagulation treatment. The synergistic effect of radiation and ozone was studied by using phenol and ethylene glycol. The chain reaction was observed in the radiation induced oxidation. The combination of radiation and ozone is considered to be one of the most useful method. In this report, the mechanism of each reaction and the applicability of the reaction to the treatment of waste water are discussed. (author)

Interaction mechanisms of radioactive, chemical and thermal releases from the nuclear industry: Methodology for considering co-operative effects

International Nuclear Information System (INIS)

Streffer, C.

1975-01-01

A number of chemicals are known which can modify radiation effects on cell killing, carcinogenesis and mutagenesis. In this paper data are reported for radiosensitizing agents. In order to discuss the interaction mechanisms of these synergistic effects, the action of radiation on DNA, on its biological functions and on its metabolism are explained briefly. Also it is indicated that part of the radiation effects in the DNA can be 'repaired' and that living cells can recover from radiation damage. One group of radiosensitizers interacts with cellular DNA or with the DNP-complex. These reactions change the configurational structure or metabolism of DNA and DNP. In this connection the action of antibiotics such as actinomycin D, and the action of SH-blocking agents such as iodoacetamide and NEM, as well as the action of alkylating agents, are discussed. A second group of radiosensitizers, especially with hypoxic cells, are the electron affinic chemicals like nitro-compounds, ketones and others. Data are also given on the modification of radiation effects by changes in temperature. Further, the problem of whether synergistic effects are to be expected arising from the chemicals and radiation originating in the nuclear industry is considered. Data show that repair and recovery processes especially are modified by radiosensitizers. The implications of this fact on sensitization at low radiation doses and at low dose rates, as well as the effect of high LET radiation, are considered. It is of interest that the dose modifying factor of some sensitizers can reach a magnitude of a factor of two to three. (author)

Radiation physical chemistry effects on organic detectors

International Nuclear Information System (INIS)

Mesquita, C.H.; Duarte, C.L.; Hamada, M.M.

2003-01-01

The radiation damage effect on a liquid scintillating system was evaluated in the PPO and POPOP solutes. Samples containing PPO (1%w/v) and POPOP (0.2%w/v) diluted in toluene were irradiated at different doses, using a 60 Co irradiator at 1.8 Gy/s. The transmittance and the chemical degradation of those solutes were evaluated as a function of dose. The PPO transmittance at 360 nm decayed exponentially with the dose, while the POPOP transmittance at 420 nm decayed linearly. The chemical degradation on the PPO and POPOP was fitted to a bi-exponential mathematical model as a function of dose. The first exponential (fast slope) was interpreted as damage produced by toluene radiolytics whereas the second exponential (slow slope) was interpreted as the damage caused by primary interaction of the γ-radiation with targets, i.e., γ photons that hit PPO and POPOP directly. The w (eV/damage molecule) and G (damaged molecules/100 eV) parameters were estimated in this paper

Protection against genetic hazards from environmental chemical mutagens: experience with ionizing radiation

International Nuclear Information System (INIS)

Sankaranarayanan, K.

1977-01-01

In radiation protection, the recurrent theme is, and always has been, dose limitation whether it is for occupational workers, individual members of the public or the population as a whole. The key words are 'dose' and 'limitation'. The quantitative system of dose limitation has been achieved because of a number of conceptual developments in our understanding of the mechanism of radiation action, development of radiation dosimetry, the accumulation of a vast body of quantitative information on dose-effect relationships and the effects of various biological and physical variables that affect these relationships of data on patterns and levels of exposures likely to be encountered to make estimates of the effects expected to result from such exposures, and balancing of risks to society against the benefits derived, the latter a matter of informed judgement. The philosophy has always been to avoid all unnecessary exposures and to limit the necessary exposures (justified by the benefits expected) to as low a level as reasonably achievable, social and economic factors being taken into acccount. The introduction of the concept that the system of dose limitation to the population should be based on genetic risks has stressed the need for careful planning to ensure that our genetic heritage is not endangered. Transfer of this knowledge to the field of chemical protection is discussed. (Auth.)

Somatic and genetic effects of low-level radiation

International Nuclear Information System (INIS)

Upton, A.C.

1974-01-01

Although the biological effects of ionizing radiation are probably better known than those of any other physical or chemical agent in the environment, our information about such effects has come from observations at doses and dose rates which are orders of magnitude higher than natural background environmental radiation levels. Whether, therefore biological effects occur in response to such low levels can be estimated only by extrapolation, based on assumptions about the dose-effect relationship and the mechanisms of the effects in question. Present knowledge suggests the possibility that several types of biological effects may result from low-level irradiation. The induction of heritable genetic changes in germ cells and carcinogenic changes in somatic cells are considered to be the most important from the standpoint of their potential threat to health. On the basis of existing data, it is possible to make only tentative upper limit estimates of the risks of these effects at low doses. The estimates imply that the frequency of such effects attributable to exposure at natural background radiation levels would constitute only a small fraction of their natural incidence. 148 references

Comparative experimental study of cancer induced by ionizing radiations or by chemical carcinogens

International Nuclear Information System (INIS)

Lafuma, J.

1983-01-01

Animal experiments have contributed to specify a number of parameters used in setting human safety limits for ionizing radiation. In the same way, comparisons have been made between cancers induced in man and in animals in well-defined conditions. In order to use the same experimental data for chemical carcinogens, the mechanisms of carcinogenesis should be the same, i.e. additivity of responses instead of synergy of effects, which requires the development of a new experimental method [fr

An investigation of the interactions of low doses of ionising radiation and chemical pollutants on Artemia Salina

International Nuclear Information System (INIS)

Danova, D.; Benova, K.; Hromada, R.; Falis, M.; Dvorak, P.

2004-01-01

Nuclear reactor failures present a risk of global contamination which can be affected by other environmental factors, such as chemicals. The present study has investigated the effect of low doses of gamma radiation in relation to the presence of low doses of Cr and Cd. (authors)

Chain radiation-chemical oxidation of aromatic amines in polyvinylchloride films

International Nuclear Information System (INIS)

Kolninov, O.V.; Lisovskaya, I.A.; Milinchuk, V.K.

1983-01-01

Radiation-chemical oxidation of tetramethyldiaminediphenylmethane in polyvinylchloride (PVC) and polystyrene (PS) films was investigated in the presence of CBr 4 at 300 K. Radiation yields (G) of 70 and 1 were obtained for an oxidized amine form (Am + ) in PVC and PS, resp. High yields of Am + in PVC matrix indicate the chain character of an oxidation reaction. Triplet states, which form exciplexes with CBr 4 were established to participate in oxidation reactions. The kinetic scheme suggested for the chain radiation oxidation of Am takes into account energy transfer, formation and degradation of the excited states of molecules resulting in the initiation and propagation of the chain on the account of active particles. (author)

Radiation Effects in III-V Nanowire Devices

Science.gov (United States)

2016-09-01

fabrication of an in-plane nanowire (NW) GaAs metal-oxide-semiconductor field- effect transistor (MOSFET) by focused -ion beam (FIB) etching and chemical...8725 John J. Kingman Road, MS 6201 Fort Belvoir, VA 22060-6201 T E C H N IC A L R E P O R T DTRA-TR-16-94 Radiation Effects in III-V...5f. WORK UNIT NUMBER 7. PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES) 8. PERFORMING ORGANIZATION REPORT NUMBER 9. SPONSORING / MONITORING AGENCY

Combined Effects of Radiation and Mercury on PLHC-1 Cells

Energy Technology Data Exchange (ETDEWEB)

Kim, Jin Kyu; Cha, Min Kyoung; Ryu, Tae Ho [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of); Han, Min [Hankook Samgong Co. Osan (Korea, Republic of); Nili, Mohammad [Dawnesh Radiation Research Institute, Barcelona (Spain)

2011-05-15

It is inevitable for living objects to expose themselves to multiple factors present in the environment. The combined effect of multi-factors is hard to estimate and predict in advance. Especially factors harmful to organisms can synergistically interact with each other. When the effect of the combined action is greater than expected additivity, it is called synergism or supra-additivity. Ionizing radiation can cause cell death, mainly due to its ability to produce reactive oxygen species in cells. Mercury is one of widespread environmental pollutants which is known to have toxic effects on organisms. There are many reports indicating its genotoxic potential in a variety of aquatic species. Synergistic effects of radiation and mercury on human cells was previously reported. Aerobically growing organisms suffer from exposure to oxidative stress, caused by partially reduced forms of molecular oxygen, known as reactive oxygen species. These are highly reactive and capable of damaging cellular constituents such as DNA, lipids and proteins. Consequently, cells from many different organisms have evolved mechanisms to protect their components against reactive oxygen species. Reactive oxygen species can also be formed by exposure of cells either to ionizing radiation or redox cycling chemicals present in the environment like heavy metals. PLHC-1 hepatoma cell line derived from top minnow (Poeciliopsis lucida) is the most commonly used cell line in toxicology. The PLHC-1 cells are easy to cultivate, and can be used for screening the toxicity of chemicals. The present study was done to evaluate the combined effects of radiation with mercury chloride on the PLHC-1 cells

Ionizing radiation effects of Cobalt-60 on the physical-chemical, sensorial and microbiological of bread with addition of linseed (Linum usitatissimum)

International Nuclear Information System (INIS)

Moura, Neila Camargo de

2011-01-01

The incorporation of functional ingredients on breading products has grown very much lately, because of the preoccupation with the consumers' health. The linseed has awakened the interest by its high level of fiber, lignin, omega-3 and antioxidants compounds. The objective of the present work is evaluate the ionizing radiation effect of 60 Co on the physical-chemical, sensorial and microbiological characteristics of bread with addition of different concentration of brown linseed. There were elaborated 3 types of bread: French roll, form bread prepared with the mixture and form bread produced with conventional ingredients. It was added smashed brown linseed on the bread dough, with concentrations of 8% and 12%. After the preparation, the three kinds of bread packed with polypropylene packages and taken to the IPEN/USP (Institute of Nuclear Energetic Research/University of São Paulo) and irradiated with doses of 6, 8 and 10 kGy. Treatments were elaborated without the addition of linseed and without irradiation, for control, totalizing 12 distinct treatments, to each bread formula tested. Chemical analyses were made (centesimal composition, anti-nutritional compounds, anti-oxidant activity, glycemic index, fat acids, complex B vitamins and minerals); physical analyses (cooking index, volume, color and water activity); sensorial analyses (preference tests and Descriptive Quantitative Analysis - ADQ); microbiological analysis and a survey about irradiated products. It could be seen that the addition of linseed was efficient to increase the level of alimentary fiber and the level of lipids on the 3 bread formula. The three kinds of bread that received the linseed addition and that were not irradiated presented increase on the level of total phenolic; however, when the samples which received the linseed addition were submitted to the irradiation process, it could be noticed the decrease of the antioxidant capacity. There was an increase on the level of omega-3

Radiation in complex exposure situations. Assessing health risks at low levels from concomitant exposures to radiation and chemicals

International Nuclear Information System (INIS)

Hornhardt, S.; Jung, T.; Burkart, W.

2000-01-01

Health effects from exposures to ionizing radiation are in general the result of complex multi-step reaction chains involving changes and responses on the level of molecules, cells, tissues and organisms. In environmental low dose exposure situations ionizing radiation only contributes a small fraction to the life-long attack on DNA by other exogenous and endogenous genotoxins. Nevertheless, efforts to assess and quantify deleterious effects at low exposure levels are directed mainly towards radiation as a single isolated agent, and rarely towards the concomitant presence of other natural and anthropogenic toxicants. Only these combined exposures may lead to observable health risk effects. In addition they might differ from those expected from simple addition of the individual risks due to interaction. The existing data base on combined effects is rudimentary, mainly descriptive and rarely covers exposure ranges large enough to make direct inferences to present day low dose exposure situations. Therefore, any risk assessment will have to consider the question whether combined effects, i.e. interaction between two or more agents will influence the health outcome from specific exposure situations in such a way that predictions derived from simple standard exposure situations would have to be revised. In view of the multitude of possible interactions between the large number of potentially harmful agents in the human environment, descriptive approaches will have to be supplemented by the use of mechanistic models for critical health endpoints such as cancer. Agents will have to be grouped depending on their physical or chemical mode of action at the molecular and cellular level, to generalize and predict the outcome of combined exposures at low exposure levels and the possibility of interactions. (author)

Development of a global 1-D chemically radiatively coupled model and an introduction to the development of a chemically coupled General Circulation Model

International Nuclear Information System (INIS)

Akiyoshi, H.

1997-01-01

A global one-dimensional, chemically and radiatively coupled model has been developed. The basic concept of the coupled model, definition of globally averaged zenith angles, the formulation of the model chemistry, radiation, the coupled processes, and profiles and diurnal variations of temperature and chemical species at a normal steady state are presented. Furthermore, a suddenly doubled CO 2 experiment and a Pinatubo aerosol increase experiment were performed with the model. The time scales of variations in ozone and temperature in the lower stratosphere of the coupled system in the doubled CO 2 experiment was long, due to a feedback process among ultra violet radiation, O(1D), NO y , NO x , and O 3 . From the Pinatubo aerosol experiment, a delay of maximum ozone decrease from the maximum aerosol loading is shown and discussed. Developments of 3-D chemical models with coupled processes are briefly described, and the ozone distribution from the first version of the 3-D model are presented. Chemical model development in National Institute for Environmental Studies (NIES) are briefly described. (author)

Effects of heat, radiation, and thermoradiation on the filterability of sewage sludge

International Nuclear Information System (INIS)

Carter, C.V.

1978-01-01

The effects of heat, radiation and thermoradiation processes on the dewatering properties of raw and primary digested sewage sludges were investigated. These effects were measured by observing the changes in filterability subsequent to treatment. Thermal treatment (40 0 to 95 0 C) of the sewage sludge resulted in decreased filterability. Radiation and thermoradiation treatment increased the filterability, the increase being dose and temperature dependent. These treatment methods are not as effective as chemical additives in increasing the filterability of sewage sludge. The combined use of radiation and organic polymer conditioner shows no significant improvement in the filterability of sewage sludge over the use of polymer alone. There appears to be some interaction; however, it shows no useful synergistic effect

Gamma radiation effects on vitamin C standard solutions

International Nuclear Information System (INIS)

Amaro, Jose Daniel V.; Mansur Netto, Elias

1995-01-01

This word shows the physical - chemical effects of gamma radiation on standard solutions of vitamin C. Samples with concentration of 50 mg/ml were exposed to different doses of gamma radiations: 1,0 2,5 and 5,0 kGy, using a cobalt-60 source, with storing periods of 0,15 and 30 days. The results showed a vitamin C concentration loss, with a minimum of 17% for the dose of 1,0 kGy immediately after irradiation and a maximum of 81% for the dose of 5 kGy and 30 days after irradiation. (author). 3 refs., 2 tabs

Patterning characteristics of a chemically-amplified negative resist in synchrotron radiation lithography

International Nuclear Information System (INIS)

Deguchi, Kimiyoshi; Miyoshi, Kazunori; Ishii, Tetsuyoshi; Matsuda, Tadahito

1992-01-01

To explore the applicability of synchrotron radiation X-ray lithography for fabricating sub-quartermicron devices, we investigate the patterning characteristics of the chemically-amplified negative resist SAL601-ER7. Since these characteristics depend strongly on the conditions of the chemical amplification process, the effects of post-exposure baking and developing conditions on sensitivity and resolution are examined. The resolution-limiting factors are investigated, revealing that pattern collapse during the development process and fog caused by Fresnel diffraction, photo-electron scattering, and acid diffusion in the resist determine the resolution and the maximum aspect ratio of the lines and spaces pattern. Using the model of a swaying beam supported at one end, it is shown that pattern collapse depends on the resist pattern's flexural stiffness. Patterning stability, which depends on the delay time between exposure and baking, is also discussed. (author)

Effects of increased solar ultraviolet radiation on biogeochemical cycles

International Nuclear Information System (INIS)

Zepp, R.G.; Callaghan, T.V.; Erickson, D.J.

1995-01-01

Increases in solar UV radiation could affect terrestrial and aquatic biogeochemical cycles thus altering both sources and sinks of greenhouse and chemically important trace gases (e.g., carbon dioxide (CO2), carbon monoxide (CO), carbonyl sulfide (COS). In terrestrial ecosystems, increased UV-B could modify both the production and decomposition of plant matter with concomitant changes in the uptake and release of atmospherically important trace gases. Decomposition processes can be accelerated when UV-B photodegrades surface litter, or retarded when the dominant effect involves changes in the chemical composition of living tissues that reduce the biodegradability of buried litter. These changes in decomposition can affect microbial production of CO2 and other trace gases and also may affect the availability of nutrients essential for plant growth. Primary production can be reduced by enhanced UV-B, but the effect is variable between species and even cultivars of some crops. Likewise, the effects of enhanced UV-B on photoproduction of CO from plant matter is species-dependent and occurs more efficiently from dead than from living matter. Aquatic ecosystems studies in several different locations have shown that reductions in current levels of solar UV-B result in enhanced primary production, and Antarctic experiments under the ozone hole demonstrated that primary production is inhibited by enhanced UV-B. In addition to its effects on primary production, solar UV radiation can reduce bacterioplankton growth in the upper ocean with potentially important effects on marine biogeochemical cycles. Decomposition processes can be retarded when bacterial activity is suppressed by enhanced UV-B radiation or stimulated when solar UV radiation photodegrades aquatic dissolved organic matter. Photodegradation of DOM results in loss of UV absorption and formation of dissolved inorganic carbon, CO, and organic substrates that are readily mineralized or taken up by aquatic

Initial events in the cellular effects of ionizing radiations: clustered damage in DNA

International Nuclear Information System (INIS)

Goodhead, D.T.

1994-01-01

Ionizing radiations produce many hundreds of different simple chemical products in DNA and also multitudes of possible clustered combinations. The simple products, including single-strand breaks, tend to correlate poorly with biological effectiveness. Even for initial double-strand breaks, as a broad class, there is apparently little or no increase in yield with increasing ionization density, in contrast with the large rise in relative biological effectiveness for cellular effects. Track structure analysis has revealed that clustered DNA damage of severity greater than simple double-strand breaks is likely to occur at biologically relevant frequencies with all ionizing radiations. Studies are in progress to describe in more detail the chemical nature of these clustered lesions and to consider the implications for cellular repair. (author)

Radiation Effects in Nuclear Waste Materials

International Nuclear Information System (INIS)

Weber, William J.; Wang, Lumin; Hess, Nancy J.; Icenhower, Jonathan P.; Thevuthasan, Suntharampillai

2003-01-01

The objective of this project is to develop a fundamental understanding of radiation effects in glasses and ceramics, as well as the influence of solid-state radiation effects on aqueous dissolution kinetics, which may impact the performance of nuclear waste forms and stabilized nuclear materials. This work provides the underpinning science to develop improved glass and ceramic waste forms for the immobilization and disposition of high-level tank waste, excess plutonium, plutonium residues and scrap, other actinides, and other nuclear waste streams. Furthermore, this work is developing develop predictive models for the performance of nuclear waste forms and stabilized nuclear materials. Thus, the research performed under this project has significant implications for the immobilization of High-Level Waste (HLW) and Nuclear Materials, two mission areas within the Office of Environmental Management (EM). With regard to the HLW mission, this research will lead to improved understanding of radiation-induced degradation mechanisms and their effects on dissolution kinetics, as well as development of predictive models for waste form performance. In the Nuclear Materials mission, this research will lead to improvements in the understanding of radiation effects on the chemical and structural properties of materials for the stabilization and long-term storage of plutonium, highly-enriched uranium, and other actinides. The research uses plutonium incorporation, ion-beam irradiation, and electron-beam irradiation to simulate the effects of alpha decay and beta decay on relevant glasses and ceramics. The research under this project has the potential to result in improved glass and ceramic materials for the stabilization and immobilization of high-level tank waste, plutonium residues and scraps, surplus weapons plutonium, highly-enriched uranium, other actinides, and other radioactive materials

Radiation Effects in Nuclear Waste Materials

International Nuclear Information System (INIS)

Weber, William J.

2005-01-01

The objective of this project is to develop a fundamental understanding of radiation effects in glasses and ceramics, as well as the influence of solid-state radiation effects on aqueous dissolution kinetics, which may impact the performance of nuclear waste forms and stabilized nuclear materials. This work provides the underpinning science to develop improved glass and ceramic waste forms for the immobilization and disposition of high-level tank waste, excess plutonium, plutonium residues and scrap, other actinides, and other nuclear waste streams. Furthermore, this work is developing develop predictive models for the performance of nuclear waste forms and stabilized nuclear materials. Thus, the research performed under this project has significant implications for the immobilization of High-Level Waste (HLW) and Nuclear Materials, two mission areas within the Office of Environmental Management (EM). With regard to the HLW mission, this research will lead to improved understanding of radiation-induced degradation mechanisms and their effects on dissolution kinetics, as well as development of predictive models for waste form performance. In the Nuclear Materials mission, this research will lead to improvements in the understanding of radiation effects on the chemical and structural properties of materials for the stabilization and long-term storage of plutonium, highly-enriched uranium, and other actinides. The research uses plutonium incorporation, ion-beam irradiation, and electron-beam irradiation to simulate the effects of alpha decay and beta decay on relevant glasses and ceramics. The research under this project has the potential to result in improved glass and ceramic materials for the stabilization and immobilization of high-level tank waste, plutonium residues and scraps, surplus weapons plutonium, highly-enriched uranium, other actinides, and other radioactive materials

Effect of MeV Electron Radiation on Europa’s Surface Ice Analogs

Science.gov (United States)

Gudipati, Murthy; Henderson, Bryana; Bateman, Fred

2017-10-01

MeV electrons that impact Europa’s trailing hemisphere and cause both physical and chemical alteration of the surface and near-surface. The trailing hemisphere receives far lower fluxes above 25 MeV as compared with lower energy particles, but can cause significant chemical and physical modifications at these energies. With NASA's planned Europa Clipper mission and a Europa Lander Concept on the horizon, it is critical to understand and quantify the effect of Europa’s radiation environment on the surface and near surface.Electrons penetrate through ice by far the deepest at any given energy compared to protons and ions, making the role of electrons very important to understand. In addition, secondary radiation - Bremsstrahlung, in X-ray wavelengths - is generated during high-energy particle penetration through solids. Secondary X-rays are equally lethal to life and penetrate even deeper than electrons, making the cumulative effect of radiation on damaging organic matter on the near surface of Europa a complex process that could have effects several meters below Europa’s surface. Other physical properties such as coloration could be caused by radiation.In order to quantify this effect under realistic Europa trailing hemisphere conditions, we devised, built, tested, and obtained preliminary results using our ICE-HEART instrument prototype totally funded by JPL’s internal competition funding for Research and Technology Development. Our Ice Chamber for Europa High-Energy Electron And Radiation-Environment Testing (ICE-HEART) operates at ~100 K. We have also implemented a magnet that is used to remove primary electrons subsequent to passing through an ice column, in order to determine the flux of secondary X-radiation and its penetration through ice.Some of the first results from these studies will be presented and their relevance to understand physical and chemical properties of Europa’s trailing hemisphere surface.This work has been carried out at Jet

Technical sheets of ionizing radiations. 2. Non-ionizing radiations

International Nuclear Information System (INIS)

Anon.

1975-01-01

The biological effects of different non-ionizing radiations are studied: ultra-violet radiation, visible radiation, infrared radiation, micrometric waves, ultrasonics. In spite of their apparent diversity these radiations are similar in their physico-chemical effects, but in view of their widely varying production methods and types of application each type is considered separately. It is pointed out that no organization resembling the CIPR exists in the field of non-ionizing radiations, the result being a great disparity amongst the different legislations in force [fr

Dose rate effect on material aging due to radiation. [Gamma radiation

Energy Technology Data Exchange (ETDEWEB)

Okamoto, Shin-ichi (Radiation Center of Osaka Prefecture, Sakai (Japan)); Hayakawa, Chikara; Takeya, Chikashi

1982-12-01

Although many reports have been presented on the radiation aging of the organic materials for electric cables, those have been based on the experiments carried out at high dose rate near 1 x 10/sup 6/ rad/h, assuming that aging effect depends on only radiation dose. Therefore, to investigate the aging behaviour in low dose rate range is an important subject to predict their practical life time. In this report, the results of having investigated the aging behaviour of six types of materials are described, (polyethylene for general insulation purpose, chemically cross-linked polyethylene, fire-retardant chemically cross-linked polyethylene, fire-retardant ethylene-propylene rubber, fire-retardant chloro-sulfonated polyethylene for sheaths, and fire-retardant, low hydrochloric acid, special heat-resistant vinyl for insulation purpose or chloroclean). They were irradiated with /sup 60/Co ..gamma..-ray at the dose from 5 x 10/sup 3/ to 1 x 10/sup 6/ rad/h, and their deterioration was tested for the items of elongation, tensile strength, resistivity, dielectric tangent and gel fraction. The aging mechanism and dose rate effect were also considered. The dose rate effect appeared or did not appear depending on the types of materials and also their properties. The materials that showed the dose rate effect included the typical ones whose characteristics degraded with the decreasing dose rate, and the peculiar ones whose deterioration of characteristics did not appear constantly. Aging mechanism may vary in the case of high dose rate and low dose rate. Also, if the life time at respective dose rate in relatively higher dose rate region is clarified, the life time in low dose rate region may possibly be predicted.

Effect of gamma radiation on graphite - PTFE dry lubrication system

Science.gov (United States)

Singh, Sachin; Tyagi, Mukti; Seshadri, Geetha; Tyagi, Ajay Kumar; Varshney, Lalit

2017-12-01

An effect of gamma radiation on lubrication behavior of graphite -PTFE dry lubrication system has been studied using (TR-TW-30L) tribometer with thrust washer attachment in plane contact. Different compositions of graphite and PTFE were prepared and irradiated by gamma rays. Gamma radiation exposure significantly improves the tribological properties indicated by decrease in coefficient of friction and wear properties of graphite -PTFE dry lubrication system. SEM and XRD analysis confirm the physico-chemical modification of graphite-PTFE on gamma radiation exposure leading to a novel dry lubrication system with good slip and anti friction properties.

Applications of synchrotron radiation to Chemical Engineering Science: Workshop report

International Nuclear Information System (INIS)

1991-07-01

This report contains extended abstracts that summarize presentations made at the Workshop on Applications of Synchrotron Radiation to Chemical Engineering Science held at Argonne National Laboratory (ANL), Argonne, IL, on April 22--23, 1991. The talks emphasized the application of techniques involving absorption fluorescence, diffraction, and reflection of synchrotron x-rays, with a focus on problems in applied chemistry and chemical engineering, as well as on the use of x-rays in topographic, tomographic, and lithographic procedures. The attendees at the workshop included experts in the field of synchrotron science, scientists and engineers from ANL, other national laboratories, industry, and universities; and graduate and undergraduate students who were enrolled in ANL educational programs at the time of the workshop. Talks in the Plenary and Overview Session described the status of and special capabilities to be offered by the Advanced Photon Source (APS), as well as strategies and opportunities for utilization of synchrotron radiation to solve science and engineering problems. Invited talks given in subsequent sessions covered the use of intense infrared, ultraviolet, and x-ray photon beams (as provided by synchrotrons) in traditional and nontraditional areas of chemical engineering research related to electrochemical and corrosion science, catalyst development and characterization, lithography and imaging techniques, and microanalysis

Applications of synchrotron radiation to Chemical Engineering Science: Workshop report

Energy Technology Data Exchange (ETDEWEB)

1991-07-01

This report contains extended abstracts that summarize presentations made at the Workshop on Applications of Synchrotron Radiation to Chemical Engineering Science held at Argonne National Laboratory (ANL), Argonne, IL, on April 22--23, 1991. The talks emphasized the application of techniques involving absorption fluorescence, diffraction, and reflection of synchrotron x-rays, with a focus on problems in applied chemistry and chemical engineering, as well as on the use of x-rays in topographic, tomographic, and lithographic procedures. The attendees at the workshop included experts in the field of synchrotron science, scientists and engineers from ANL, other national laboratories, industry, and universities; and graduate and undergraduate students who were enrolled in ANL educational programs at the time of the workshop. Talks in the Plenary and Overview Session described the status of and special capabilities to be offered by the Advanced Photon Source (APS), as well as strategies and opportunities for utilization of synchrotron radiation to solve science and engineering problems. Invited talks given in subsequent sessions covered the use of intense infrared, ultraviolet, and x-ray photon beams (as provided by synchrotrons) in traditional and nontraditional areas of chemical engineering research related to electrochemical and corrosion science, catalyst development and characterization, lithography and imaging techniques, and microanalysis.

physical, chemical, technological and biological properties of some mutant oil seeds induced by gamma radiation

International Nuclear Information System (INIS)

Ali, H.G.M.

2003-01-01

The present study has been undertaken to evaluated sesame, sunflower and safflower seeds induced by gamma rays, as plant breeding unit, plant research department, radioisotope application division, nuclear research center, atomic energy authority Inshas. the obtained results indicate the following : chemical composition of mutant seeds: the radiation mutation caused a significant increase in both oil and ash content total carbohydrates showed a significant decreased in sesame seeds. radiation mutation induced significant increase in oil and protein content of sunflower and safflower seeds. while the total carbohydrate showed a significant decrease. physiochemical properties of oils extracted mutant seeds: the radiation mutation had no real effect on the refractive index and A.V of oils extracted from control and mutant sesame, sunflower and safflower seeds. while it caused a slight increase in red color and P.V. of sesame oil, the thiobarbituric acid (TBA) value of mutant sesame oil was not alter upon radiation mutation, but it induced a slight decrease in TBA of mutant sunflower and safflower oils. the unsaponifiable matter percentage of oils extracted from mutant sesame, sunflower and safflower seeds were slightly increased by radiation mutation .radiation mutation of seeds had no real effect on the total SFA and USFA of sesame oil. however, radiation mutation induced a remarkable changes in fatty acid profiles of sunflower and safflower oil as total SFA decreased, while USFA increased. Uric acid was only detected in oil extracted from mutant sunflower seeds

The combined effect of the gamma radiations of 60 Co and different chemicals on the cells of the radicular vegetative tip of Allium sativum L

International Nuclear Information System (INIS)

Dumitrescu, Rodica; Popescu, D.; Andrei, M.

1999-01-01

The gamma ionizing radiations used alone in the treatment of Allium Sativum L. affected differently the cells belonging to the two zones of the root causing modifications of the cellular parameters which have been previously estimated. Data in the literature established that the damage of the interphasic nucleus of the cells determines the obstruction of the DNA synthesis and the delay of the cell mitosis. Sparrow, A. H., Miller, M. W. and Al-Rubeai confirmed the existence of a relationship between the nuclear volumes and the radiosensitivity of the different types of cells. The aim of this experiment was to counteract the harmful effect of gamma radiations at cellular level with the help of combined treatments, namely, the gamma radiations associated with different chemicals having radioprotective effects. The biological significance of the obtained values was established by statistical calculations with the help of the Student (t) test. The values of the estimated cellular parameters, NV, ICV, CV, NCR showed that, although there were certain fluctuations, their values were not always significant. (author)

Assessment of the biological effects of 'strange' radiation

International Nuclear Information System (INIS)

Pryakhin, E.A.; Tryapitsina, G.A.; Urutskoyev, L.I.; Akleyev, A.V.

2006-01-01

The results from studies of the effects produced by electrical explosions of foils made from super pure materials in water point to the emergence of new chemical elements. An additional finding was the discharge of 'strange' radiation accompanying the transformation of chemical elements. However, currently, the mechanism involved in the interaction between 'strange' radiation and a substance or a biological entity remains obscure. Therefore, the aim of the present research is to investigate the biological effects of the 'strange' radiation. Pilot studies were performed at the RECOM RRC 'Kurchatov Institute' in April-May of 2004. The animals used in the experiment were female mice of C57Bl/6 line aged 80 days with body weight 16-18 g. The animals were exposed to radiation discharged during explosions of Ti foils in water and aqueous solutions. The cages with animals were placed at 1 m from the epicenter of the explosion. Explosions were carried out on the 19. (3 explosions), 20. (4 explosions) and 22. (3 explosions) of April, 2004 (explosions No1373 - No1382, respectively). The animals were assigned to 4 experimental groups comprised of 17-20 mice per group. The animals received experimental exposure within 1, 2 and 3 days of the experiment. In total, the experimental groups were exposed to 3, 7 and 10 explosions, respectively. In order to identify the biological reactions, the following parameters were estimated: number of nucleated cells in the bone marrow, number of CFU in the spleen after additional gamma-irradiation (6 Gy), cell composition of the bone marrow, the rate of erythrocytes with the different level of maturation in the bone marrow, the rate of erythrocytes with the micronuclei in the bone marrow, the reaction of bone marrow cells to additional gamma-irradiation (2 Gy), number of leucocytes in the peripheral blood, and cell composition of the peripheral blood. The following conclusions were drawn from these studies: 1. 'strange' radiation resulting

Dosimetry of ionizing radiation

International Nuclear Information System (INIS)

Musilek, L.; Seda, J.; Trousil, J.

1992-01-01

The publication deals with a major field of ionizing radiation dosimetry, viz., integrating dosimetric methods, which are the basic means of operative dose determination. It is divided into the following sections: physical and chemical effects of ionizing radiation; integrating dosimetric methods for low radiation doses (film dosimetry, nuclear emulsions, thermoluminescence, radiophotoluminescence, solid-state track detectors, integrating ionization dosemeters); dosimetry of high ionizing radiation doses (chemical dosimetric methods, dosemeters based on the coloring effect, activation detectors); additional methods applicable to integrating dosimetry (exoelectron emission, electron spin resonance, lyoluminescence, etc.); and calibration techniques for dosimetric instrumentation. (Z.S.). 422 refs

Lethal and mutagenic effects of radiation and chemicals on cultured fish cells derived the erythrophoroma of goldfish (Carassius auratus)

Energy Technology Data Exchange (ETDEWEB)

Mitani, H. (Tokyo Univ. (Japan). Inst. of Zoology)

1983-01-01

GEM 199 cells derived from an eryhtrophoroma of goldfish (Carassius auratus), which had a high plating efficiency, were used to investigate the lethal and mutational effects of radiations (UV and ..gamma..-rays) and chemicals (4NQO and MNNG). The cells were more resistant to rays than mammalian cells and CAF-MM1 cells derived from the normal fin tissue of goldfish. They were also more resistant to UV-irradiation than CAF-MM1 cells. Photoreactivation after UV-irradiation was present in GEM 199 cells for both survival and mutation. The initial shoulder of the survival curve of UV-irradiated cells was reduced greatly by caffeine, suggesting a high activity of the post-replication repair. The spontaneous mutation frequency to ouabain resistance was 1-5x10/sup -6/ clones per viable cell. MNNG was effective in inducing ouabain-resistant mutation, while 4NQO and ..gamma..-rays did not induce mutation.

Effect of gamma radiation on polyvinylpyrrolidone hydrogels

International Nuclear Information System (INIS)

Oliveira, M.J.A.; Vásquez, P.A.S.; Alcântara, M.T.S.; Munhoz, M.M.L.; Lugão, A.B.

2017-01-01

Polyvinylpyrrolidone (PVP) hydrogels have been investigated as drug delivery matrices for the treatment of wounds, such as cutaneous leishmaniasis, and matrices with silver nanoparticles for chronic wounds and burns. The preparation of such hydrogels can occur by various cross-linking methods, such as gamma, chemical, physical, among others. The most feasible for wound dressings is gamma irradiation from cobalt-60, because gamma irradiation simultaneously promotes crosslinking and sterilization, leaving the wound dressing ready for use. The objective of this work was to investigate the effect on physico- chemical properties of gamma radiation on PVP hydrogel according to the radiation absorbed dose variation. The PVP hydrogels were irradiated with doses of 5, 15, 25, 35, 45, 55, 65, 75 and 95kGy at dose rate of 5 kGy/h and characterized by swelling, thermogravimetric and mechanical analysis. Results shown a favorable dose range window for processing of these hydrogels related to the application. The results showed that mechanical strength was affected at doses starting at 25 kGy. (author)

Effect of gamma radiation on polyvinylpyrrolidone hydrogels

Energy Technology Data Exchange (ETDEWEB)

Oliveira, M.J.A.; Vásquez, P.A.S.; Alcântara, M.T.S.; Munhoz, M.M.L.; Lugão, A.B., E-mail: mariajhho@yahoo.com.br, E-mail: pavsalva@ipen.br, E-mail: ablugao@ipen.br [Instituto de Pesquisas Energéticas e Nucleares (IPEN/CNEN-SP), São Paulo, SP (Brazil)

2017-07-01

Polyvinylpyrrolidone (PVP) hydrogels have been investigated as drug delivery matrices for the treatment of wounds, such as cutaneous leishmaniasis, and matrices with silver nanoparticles for chronic wounds and burns. The preparation of such hydrogels can occur by various cross-linking methods, such as gamma, chemical, physical, among others. The most feasible for wound dressings is gamma irradiation from cobalt-60, because gamma irradiation simultaneously promotes crosslinking and sterilization, leaving the wound dressing ready for use. The objective of this work was to investigate the effect on physico- chemical properties of gamma radiation on PVP hydrogel according to the radiation absorbed dose variation. The PVP hydrogels were irradiated with doses of 5, 15, 25, 35, 45, 55, 65, 75 and 95kGy at dose rate of 5 kGy/h and characterized by swelling, thermogravimetric and mechanical analysis. Results shown a favorable dose range window for processing of these hydrogels related to the application. The results showed that mechanical strength was affected at doses starting at 25 kGy. (author)

Effects of solar radiation on hair and photoprotection.

Science.gov (United States)

Dario, Michelli F; Baby, André R; Velasco, Maria Valéria R

2015-12-01

In this paper the negative effects of solar radiation (ultraviolet, visible and infrared wavelengths) on hair properties like color, mechanical properties, luster, protein content, surface roughness, among others, will be discussed. Despite knowing that radiation damages hair, there are no consensus about the particular effect of each segment of solar radiation on the hair shaft. The hair photoprotection products are primarily targeted to dyed hair, specially auburn pigments, and gray shades. They are usually based on silicones, antioxidants and quaternary chemical UV filters that have more affinity for negatively charged hair surface and present higher efficacy. Unfortunately, there are no regulated parameters, like for skin photoprotection, for efficacy evaluation of hair care products, which makes impossible to compare the results published in the literature. Thus, it is important that researchers make an effort to apply experimental conditions similar to a real level of sun exposure, like dose, irradiance, time, temperature and relative humidity. Copyright © 2015 Elsevier B.V. All rights reserved.

Thermal radiation and chemical reaction effects on MHD free convection heat and mass transfer in a micropolar fluid

International Nuclear Information System (INIS)

Srinivasacharya, D.; Mendu, Upendar

2011-01-01

The steady laminar free convection heat and mass transfer boundary layer flow of a thermomicropolar fluid past a non-isothermal vertical flat plate in the presence of a homogeneous first order chemical reaction and a radiation with transverse magnetic field has been reported. It has been established that the flow problem has similarity solutions when the variation in temperature of the plate and variation in concentration of the fluid are linear functions of the distance from the leading edge measured along the plate. The nonlinear governing equations of the flow along with their appropriate boundary conditions are initially cast into dimensionless forms using similarity transformations which are used to reduce the governing partial differential equations into ordinary differential equations. The resulting system of equations thus formed is then solved numerically by using the Keller-box method. The non-dimensional Nusselt number, Sherwood number and the skin friction coefficient and wall couple stress at the plate are derived, and a parametric study of the governing parameters, namely the magnetic field strength parameter, radiation parameter, chemical reaction parameter, Sherwood number profiles against to the coupling number as well as the skin friction coefficient, wall couple stress coefficient is conducted. (author)

The role of cellular and molecular studies in evaluation of health effects from combined radiation and chemical exposures

International Nuclear Information System (INIS)

Brooks, A.L.; Gilbert, E.S.; Kitchin, R.M.; Johnson, N.F.

1992-06-01

Additive models are currently used to predict risks following exposure to multiple agents or complex mixtures. Use of these models is questioned because different methods are used to derive risks for chemical and physical agents depending on the database used. Risks for the induction of cancer from radiation are based on large sets of human data, while standards are set for most chemical carcinogens using information derived from animal studies. However, it is not, from a scientific point of view, appropriate to add risks from physical and chemical agents to derive potential health impact from combined exposures. The range of safety factors built into the estimates, the large differences in the data sets used to evaluate and establish standards, and the differences in the basic philosophy for deriving risks for physical and chemical agents make the additive model unacceptable for estimating risks from combined exposures. To understand the potential health impacts from environmental exposure, it is important (1) to consider how risks were derived and (2) to determine if interactions exist between damage induced by the different agents to ensure that additive assumptions are valid. This presentation discusses a number of these safety factors for specific chemicals

Radiation equivalence of genotoxic chemicals - Validation in cultered mammalian cell lines

International Nuclear Information System (INIS)

Murthy, M.S.S.

1982-01-01

Published data on mutations induced by ionizing radiation and 6 monofunctional alkylating agents, namely EMS, MMS, ENNG, MNNG, ENU and MNU, in different cell lines (Chinese hamster ovary, Chinese hamster lung V79, mouse lymphoma L5178 and human cells) were analysed so that radiation-equivalent chemical (REC) values could be calculated. REC values thus obtained for a given alkylating agent with different cell lines fall within a narrow range suggesting its validation in cultured mammalian cell systems including human. (orig.)

POSSIBLE NATURE OF THE RADIATION-INDUCED SIGNAL IN NAILS: HIGH-FIELD EPR, CONFIRMING CHEMICAL SYNTHESIS, AND QUANTUM CHEMICAL CALCULATIONS

Science.gov (United States)

Tipikin, Dmitriy S.; Swarts, Steven G.; Sidabras, Jason W.; Trompier, François; Swartz, Harold M.

2016-01-01

Exposure of finger- and toe-nails to ionizing radiation generates an Electron Paramagnetic Resonance (EPR) signal whose intensity is dose dependent and stable at room temperature for several days. The dependency of the radiation-induced signal (RIS) on the received dose may be used as the basis for retrospective dosimetry of an individual's fortuitous exposure to ionizing radiation. Two radiation-induced signals, a quasi-stable (RIS2) and stable signal (RIS5), have been identified in nails irradiated up to a dose of 50 Gy. Using X-band EPR, both RIS signals exhibit a singlet line shape with a line width around 1.0 mT and an apparent g-value of 2.0044. In this work, we seek information on the exact chemical nature of the radiation-induced free radicals underlying the signal. This knowledge may provide insights into the reason for the discrepancy in the stabilities of the two RIS signals and help develop strategies for stabilizing the radicals in nails or devising methods for restoring the radicals after decay. In this work an analysis of high field (94 GHz and 240 GHz) EPR spectra of the RIS using quantum chemical calculations, the oxidation–reduction properties and the pH dependence of the signal intensities are used to show that spectroscopic and chemical properties of the RIS are consistent with a semiquinone-type radical underlying the RIS. It has been suggested that semiquinone radicals formed on trace amounts of melanin in nails are the basis for the RIS signals. However, based on the quantum chemical calculations and chemical properties of the RIS, it is likely that the radicals underlying this signal are generated from the radiolysis of L-3,4-dihydroxyphenylalanine (DOPA) amino acids in the keratin proteins. These DOPA amino acids are likely formed from the exogenous oxidation of tyrosine in keratin by the oxygen from the air prior to irradiation. We show that these DOPA amino acids can work as radical traps, capturing the highly reactive and unstable

Activation of chemical biological defense mechanisms and remission of vital oxidative injury by low dose radiation

International Nuclear Information System (INIS)

Yamaoka, K.; Nomura, T.; Kojima, S.

2000-01-01

Excessive active oxygen produced in vivo by various causes is toxic. Accumulation of oxidation injuries due to excessive active causes cell and tissue injuries, inducing various pathologic conditions such as aging and carcinogenesis. On the other hand, there are chemical defense mechanisms in the body that eliminate active oxygen or repair damaged molecules, defending against resultant injury. It is interesting reports that appropriate oxidation stress activate the chemical biological defense mechanisms. In this study, to elucidate these phenomena and its mechanism by low dose radiation, we studied on the below subjects. Activation of chemical biological defense mechanisms by low dose radiation: (1) The effects radiation on lipid peroxide (LPO) levels in the organs, membrane fluidity and the superoxide dismutase (SOD) activity were examined in rats and rabbits. Rats were irradiated with low dose X-ray over their entire bodies, and rabbits inhaled vaporized radon spring water, which primarily emitted α-ray. The following results were obtained. Unlike high dose X-ray, low dose X-ray and radon inhalation both reduced LPO levels and made the state of the SH-group on membrane-bound proteins closer to that of juvenile animals, although the sensitivity to radioactivity varied depending on the age of the animals and among different organs and tissues. The SOD activity was elevated, suggesting that low dose X-ray and radon both activate the host defensive function. Those changes were particularly marked in the organs related to immune functions of the animals which received low dose X-ray, while they were particularly marked in the brain after radon inhalation. It was also found that those changes continued for longer periods after low dose X-irradiation. (2) Since SOD is an enzyme that mediates the dismutation of O 2 - to H 2 O 2 , the question as to whether the resultant H 2 O 2 is further detoxicated into H 2 O and O 2 or not must still be evaluated. Hence, we studied

Some radiation chemical aspects of nuclear engineering

International Nuclear Information System (INIS)

Pikaev, A.K.; Kabakchi, S.A.; Egorov, G.F.

1988-01-01

Some radiation chemical aspects of nuclear engineering are discussed (predominantly on the base of the works performed in the Soviet Union). The data on the influence of temperature within the range of 0-300 0 C on the yields of water radiolysis products are considered. The results obtained from the study of reactivity of actinide ions towards inorganic free radicals in acid aqueous solutions are summarized. The information on composition and properties of the products of radiolytic transformations of different extragents and diluents and on their influence on the behaviour of extraction systems during processing of irradiated nuclear fuel is presented. (author)

Double stratification effects in chemically reactive squeezed Sutterby fluid flow with thermal radiation and mixed convection

Science.gov (United States)

Ahmad, S.; Farooq, M.; Javed, M.; Anjum, Aisha

2018-03-01

A current analysis is carried out to study theoretically the mixed convection characteristics in squeezing flow of Sutterby fluid in squeezed channel. The constitutive equation of Sutterby model is utilized to characterize the rheology of squeezing phenomenon. Flow characteristics are explored with dual stratification. In flowing fluid which contains heat and mass transport, the first order chemical reaction and radiative heat flux affect the transport phenomenon. The systems of non-linear governing equations have been modulating which then solved by mean of convergent approach (Homotopy Analysis Method). The graphs are reported and illustrated for emerging parameters. Through graphical explanations, drag force, rate of heat and mass transport are conversed for different pertinent parameters. It is found that heat and mass transport rate decays with dominant double stratified parameters and chemical reaction parameter. The present two-dimensional examination is applicable in some of the engineering processes and industrial fluid mechanics.

Chemical composition effects of methylene containing polymers on gas emission under γ-irradiation

Energy Technology Data Exchange (ETDEWEB)

Ferry, M., E-mail: muriel.ferry@cea.fr [CEA, DEN, DPC, SECR, LRMO, F-91191 Gif-sur-Yvette (France); Dannoux-Papin, A. [CEA, DEN, DPC, SECR, LRMO, F-91191 Gif-sur-Yvette (France); Dély, N. [CEA, DSM, IRAMIS, LIDYL, PCR, F-91191 Gif-sur-Yvette (France); Legand, S.; Durand, D.; Roujou, J.L.; Lamouroux, C.; Dauvois, V. [CEA, DEN, DPC, SECR, LRMO, F-91191 Gif-sur-Yvette (France); Coignet, P.; Cochin, F. [AREVA NC DOR/RDP, 1 place Jean Millier, 92084 La Défense (France); Esnouf, S. [CEA, DEN, DPC, SECR, LRMO, F-91191 Gif-sur-Yvette (France); CEA, DSM, IRAMIS, LIDYL, PCR, F-91191 Gif-sur-Yvette (France)

2014-09-01

The presence of different chemical groups in methylene containing polymers can lead to very different behaviors under ionizing radiation. To better understand the effect of these groups on gas production under γ-irradiation, especially on hydrogen formation, and to study the efficiency of energy transfer between chemical groups, several methylene containing polymers with different controlled group concentrations were studied in inert atmosphere. We analyzed the influence of the nature and position of the chemical group using methylene containing copolymers with aliphatic side-chains (different lengths), ester groups in the side-chains (different concentrations) and ester groups in the polymer backbone (different concentrations). Radiation chemical yields of H{sub 2}, CO, CO{sub 2} and CH{sub 4} were determined at room temperature by high resolution mass spectrometry. On the basis of these results, we attempt to obtain a better understanding of the mechanisms involved. It can be observed that crystallinity and aliphatic side-chain have no effect on hydrogen formation. On contrary, esters on side-chain and in the backbone have an important influence on hydrogen formation, with the most important effect when esters groups are in the backbone. In these two kind of materials, energy fraction transferred from methylene to ester groups has been quantified and only 10 wt% (or less) of ester groups are sufficient to protect effectively the aliphatic moiety.

Effect of Gamma Radiation on Microbial load, Chemical and Sensory Properties of Sheesh Tawoq, Prepared Chilled Meal

International Nuclear Information System (INIS)

Al-Bachir, M.

2011-01-01

Locally prepared meal Sheesh Tawoq was treated with 0, 2, 4 or 6 kGy doses of gamma irradiation. Treated and untreated Sheesh Tawoq were kept in a refrigerator (1 and 4 mC). Microbiological, chemical and sensory characteristics of Sheesh Tawoq were evaluated at 0, 4, 8, 12, 16 and 20th week of storage. The results indicate that 4 and 6 kGy doses of gamma irradiation decreased the total counts of mesophilic aerobic bacteria, total coliform and yeast. Thus the microbiological shelf-life of Sheesh Tawoq was significantly extended from 12 weeks (control) to more than 20 weeks (samples treated with 4 or 6 kGy). Irradiation doses did not have a significant effect on the major constituents of Sheesh Tawoq (moisture, protein and fats). The radiation doses required to reduce the microorganisms load one log cycle (D 1 0 ) in Sheesh Tawoq were 435 and 385 Gy for the Salmonella and E. coli , respectively. The chemical parameters, total acidity and volatile basic nitrogen, which were chosen as the indices of freshness, were all well within the acceptable limit for up to 12 weeks for Sheesh Tawoq treated with 0 and 2 kGy, and for up to 20 weeks at 1 and 4 mC for samples treated with 4 and 6 kGy. Sensory evaluation showed no significant differences between irradiated and non-irradiated samples. (author)

The chemical basis of DNA damage by the direct pathway of ionizing radiation

International Nuclear Information System (INIS)

Sharma, Kiran Kumar K.

2013-01-01

Free radicals in living system has been implicated as playing a major role in the etiology of variety of diseases. The mechanism of free radicals in vivo involves predominantly the reaction with the DNA, producing different types of damage to the DNA. These lesions induced to the DNA could lead to mutation and even cell death. Radiolysis techniques, which uses ionizing radiation has proven to be one of the most advanced and excellent tool for studying the free radical reaction mechanisms as it can produce a host of well characterized free radicals. The effects of ionizing radiation on DNA have been studied for many years. Ionizing radiation interacts with DNA in vivo by two pathways, direct and indirect. The indirect accounts for 50-60% while the direct effect accounts for 40-50%. The chemical mechanism of the former reaction arising mainly from the reactive species produced by radiolysis of water has been extensively studied, however with respect to the later pathway, which creates holes and electrons to the DNA molecule using DNA films and crystals is an active area of research as both the pathways plays important roles in DNA damage in vivo particularly in chromosomal DNA which are tightly bound with histones and compartmentalized

Gamma radiation effects on chemical composition and color of raspberries (Rubus Idaeus L.) and blueberries (Vaccinium Corymbosum) cultivated in South of Chile

International Nuclear Information System (INIS)

Urbina P, M.C.; Manquian T, N.

1988-01-01

Raspberries and blueberries grown in the X th Region, Valdivia, were irradiated in a 137 Cs irradiador BPCDI (Brookhaven Portable Cesium Development irradiator) with dosis of 1,5 KGy and 2,5 KGy in order to measure the effect on the chemical composition and the changes of color due to pigments damage using a colorimetric method. Analysis of pH, soluble solids, titratable acidity, dry matter, total sugar and vitamin C were made. Color was analized comparing the pink color of the diluted fruit juice with a color scale of different concentrations of a cobalt scale of different concentrations of cobalt chloride. Results demonstrated that the radurization treatment does not affect chemical composition with dosis up to 2,5 KGy. It was possible to detect differences of color in raspberries and not in blueberries because of the less sensitivity of color pigments to radiation. (author)

Decomposition of halogenated organic chemicals in ionic liquid by ionizing radiation

International Nuclear Information System (INIS)

Kimura, A.; Taguchi, M.; Kojima, T.; Nagaishi, R.; Hiratsuka, H.

2006-01-01

as electron scavenger under γ-ray irradiation. CP in RTILs, therefore, is considered to be reduced to phenol by solvated electron. Formation yields of phenol estimated by the ratios of G(Phenol)/G(-CP) are 17 to 82% in the alcohols, which differ by the position of chlorine on aromatic ring. On the contrary, the yields are 66% to 73% in RTILs for all types of CP. Dimers of CP were observed after irradiation in methanol but not in RTILs. These results can be explained in terms of the stabilization of solvated electron and the cage effect related to high polarity and high viscosity of RTIL, leading the longer lifetime of solvated electron. Decompositions of CP were investigated in aromatic RTILs having different viscosity. Both G(-CP) and G(Phenol) in aromatic RTILs was lower than those in alphatic ones. Decomposition of CP, therefore, is suppressed by the aromatic group scavenging the solvated electron. The G(Phenol) increased in ascending order of their viscosities.. Advanced reduction technique combined ionizing radiation with RTILs should be a promising method for halogenated organic chemicals treatment. (authors)

Radiation purification of the chemical industry effluents and possibilities of realization of this method

International Nuclear Information System (INIS)

Petryaev, E.P.; Kovalevskaya, A.M.; Shlyk, V.G.; Savushkin, I.A.; Kazazyan, V.T.

1977-01-01

Radiation-chemical methods for synthetic fibre industry effluents purification from cyanides, sulphides and monomers, as well as for disinfection of circulation water and improvement in sedimental and filtering properties of waste active slurry in petrochemical industry are described. Chemical plant effluents are purified by 70-90% from cyanides at the dose rate of 0,3 - 0,5 Mrad, by 60 - 70% from sulphides and monomers at the dose of 0,2 Mrad. Circulation water of petroleum processing plant is disinfected at the dose of 0,08 Mrad; the rates of filtration and sedimentation of waste active slurry increase two and three fold, correspondingly, at the dose of 0,6 Mrad. The power of radiation sources required for the industrial realization of radiation purification of liquid wastes has been calculated

Surgical treatment of delayed radiation effects in the skin and its indication

International Nuclear Information System (INIS)

Tilkorn, H.; Drepper, H.

1987-01-01

Since 1960 a total of 1200 patients with skin disease as delayed radiation effects were treated at the Hornheide special clinic, 40% of whom received plastic surgery. This requires knowledge of the type of radiation applied and when it was applied, additional harmful influences, exposure, differentiation in cases of ulcers between primary, cumulative, and combination effect, early radiation effects, and late radiation effects. Secondary factors leading possibly to necrosis may be: recidivation of the primary tumours, benign or malignant neoplasms, traumatic injuries such as injections, sampling, tight clothing, chemical factors like therapeuticals for local application, allergies, infections of the skin with bacteria or fungi, osteomyelitis, non-infections skin disease, and internal disease. A precondition for successful dermatological and surgical treatment are a careful review of the previous case history and exact diagnosis. Some clinical cases serve to illustrate the theoretical explanations and point out possibilities for surgical treatment. (TRV) [de

Climate-chemical interactions and effects of changing atmospheric trace gases

Science.gov (United States)

Ramanathan, V.; Callis, L.; Cess, R.; Hansen, J.; Isaksen, I.

1987-01-01

The paper considers trace gas-climate effects including the greenhouse effect of polyatomic trace gases, the nature of the radiative-chemical interactions, and radiative-dynamical interactions in the stratosphere, and the role of these effects in governing stratospheric climate change. Special consideration is given to recent developments in the investigations of the role of oceans in governing the transient climate responses, and a time-dependent estimate of the potential trace gas warming from the preindustrial era to the early 21st century. The importance of interacting modeling and observational efforts is emphasized. One of the problems remaining on the observational front is the lack of certainty in current estimates of the rate of growth of CO, O3, and NOx; the primary challenge is the design of a strategy that will minimize the sampling errors.

Radiation-chemical discussion on inverse dose-rate effect observed in radiation-induced strand breaks of plasmid DNA

International Nuclear Information System (INIS)

Masuda, Takahiro

1994-01-01

Experimental results of inverse dose-rate effect, so-called Kada Effects, which was published by Takakura and her coworkers on radiation-induced strand breaks of plasmid DNA in aerated aqueous solution, have been kinetically analyzed and discussed on the basis of radiation chemistry. the kinetic analysis indicates that there are two possible mechanisms; 1) equilibrium mixture of O 2 - and HO 2 is responsible for strand breaks of DNA, and 2) peroxyl radical produced from citrate is effective for the strand breaks. However, the detailed kinetic analysis revealed that the latter is improbable because unimolecular decay of the peroxyl radical must be assumed to be negligible for its participation despite fast decay of analogous organic peroxyl radicals. The analysis has also given 9.93±0.10 dm 3 mol -1 s -1 per nucleotide unit, which corresponds to 7.62 x 10 4 dm 3 mol -1 s -1 per DNA molecule, as the rate constant for the reaction of the equilibrium mixture with plasmid pBR 322 DNA. Furthermore the probability that the reaction of the mixture with a nucleotide unit of DNA leads to strand breaks was obtained to be 3.36 x 10 -3 for gamma-irradiated system and 1.98 x 10 -3 for beta-irradiated system, respectively. (author)

Biophysical radiation effects

International Nuclear Information System (INIS)

Fidorra, J.

1982-07-01

The biological effectiveness of ionizing radiation is based upon the absorption of energy in molecular structures of a cell. Because of the quantum nature of radiation large fluctuations of energy concentration in subcellulare regions has to be considered. In addition both the spatial distribution of a sensitive molecular target and cellulare repair processes has to be taken into consideration for an assessment of radiation action. In radiation protection the difference between the quality factor and the Relative Biological Effectiveness has a fundamental meaning and will be discussed in more detail. The present report includes a short review on some relevant models on radiation action and a short discussion on effects of low dose irradiation. (orig.) [de

Effect of radiation on preservation of convenient dish 'bowl-shape packed pig elbow'

International Nuclear Information System (INIS)

Wang Keqin; Chen Jingping; Li Wenge; Peng Weizheng

2005-01-01

The suitable parameters for radiation processing were investiqated by analyzing the microload of material and product, and radiation effect on the preservation of convenient dish 'bowl-shape packed pig elbow'. The results showed the store period of the product could be extended 2-6 month by 4.0-6.0 kGy radiation at different storage temperature. The sensory, physical and chemical index of the products met the requirement of relevant national standard of food hygiene. (authors)

A research program on radiative, chemical, and dynamical feedback progresses influencing the carbon dioxide and trace gases climate effects

International Nuclear Information System (INIS)

1989-07-01

This report summarizes the up-to-date progress. The program includes two tasks: atmospheric radiation and climatic effects and their objective is to link quantitatively the radiation forcing changes and the climate responses caused by increasing greenhouse gases. Here, the objective and approach are described. We investigate the combined atmospheric radiation characteristics of the greenhouse gases (H 2 O, CO 2 , CH 4 , N 2 O, CFCs, and O 3 ), aerosols and clouds. Since the climatic effect of increasing atmospheric greenhouse gases is initiated by perturabtion to the longwave thermal radiation, it is critical to understand better the radiation characteristics of the greenhouse gases and their relationship to radiatively-important aerosols and clouds; the latter reflect solar radiation (a cooling of the surface) and provide a greenhouse effect (a warming to the surface). Therefore, aerosol and cloud particles are an integral part of the radiation field in the atmosphere. 9 refs

Roles of radiation chemistry in development and research of radiation biology

International Nuclear Information System (INIS)

Min Rui

2009-01-01

Radiation chemistry acts as a bridge connecting radiation physics with radiation biology in spatial and temporal insight. The theory, model, and methodology coming from radiation chemistry play an important role in the research and development of radiation biology. The chemical changes induced by ionizing radiation are involved not only in early event of biological effects caused by ionizing radiation but in function radiation biology, such as DNA damage and repair, sensitive modification, metabolism and function of active oxygen and so on. Following the research development of radiation biology, systems radiation biology, accurate quality and quantity of radiation biology effects need more methods and perfect tools from radiation chemistry. (authors)

Gamma radiation physical-chemical effects on vitamin C contents in white and red guavas

International Nuclear Information System (INIS)

Amaro, Jose Daniel V.; Mansur Netto, Elias

1995-01-01

Guava (Psidium guajava L.) is valuable tropical fruit because its high C vitamin content. Red an white are the most common species of guava found in tropical areas. The ionizing radiation is normally used as a ripen ring retardant for longer storage periods. This work studies gamma radiation effects on the C vitamin concentration in white and red guava. Samples of juices were irradiated using a source of Cobalt-60, with doses of 1,0 2,5 and 5,0 kGy and storing periods of 0,15 and 30 days. The white guava juice showed a 49% loss in the C vitamin concentration with 5 kGy radiation dose, while the red guava juice showed 33% under the same condition. This shows that the juice of white guava is more sensitive to gamma radiations than the red guava. This results suggests a protection mechanism by colour pigments we believe is associated to the aromatic structures in the red specie. (author). 4 refs., 2 tabs

Protective Effect of Anthocyanins from Lingonberry on Radiation-induced Damages

Directory of Open Access Journals (Sweden)

Shuang-Qi Tian

2012-12-01

Full Text Available There is a growing concern about the serious harm of radioactive materials, which are widely used in energy production, scientific research, medicine, industry and other areas. In recent years, owing to the great side effects of anti-radiation drugs, research on the radiation protectants has gradually expanded from the previous chemicals to the use of natural anti-radiation drugs and functional foods. Some reports have confirmed that anthocyanins are good antioxidants, which can effectively eliminate free radicals, but studies on the immunoregulatory and anti-radiation effects of anthocyanins from lingonberry (ALB are less reported. In this experiment, mice were given orally once daily for 14 consecutive days before exposure to 6 Gy of gamma-radiation and were sacrificed on the 7th day post-irradiation. The results showed that the selected dose of extract did not lead to acute toxicity in mice; while groups given anthocyanins orally were significantly better than radiation control group according to blood analysis; pretreatment of anthocyanins significantly (p < 0.05 enhanced the thymus and spleen indices and spleen cell survival compared to the irradiation control group. Pretreatment with anthocyanins before irradiation significantly reduced the numbers of micronuclei (MN in bone marrow polychromatic erythrocytes (PCEs. These findings indicate that anthocyanins have immunostimulatory potential against immunosuppression induced by the radiation.

POSSIBLE NATURE OF THE RADIATION-INDUCED SIGNAL IN NAILS: HIGH-FIELD EPR, CONFIRMING CHEMICAL SYNTHESIS, AND QUANTUM CHEMICAL CALCULATIONS.

Science.gov (United States)

Tipikin, Dmitriy S; Swarts, Steven G; Sidabras, Jason W; Trompier, François; Swartz, Harold M

2016-12-01

Exposure of finger- and toe-nails to ionizing radiation generates an Electron Paramagnetic Resonance (EPR) signal whose intensity is dose dependent and stable at room temperature for several days. The dependency of the radiation-induced signal (RIS) on the received dose may be used as the basis for retrospective dosimetry of an individual's fortuitous exposure to ionizing radiation. Two radiation-induced signals, a quasi-stable (RIS2) and stable signal (RIS5), have been identified in nails irradiated up to a dose of 50 Gy. Using X-band EPR, both RIS signals exhibit a singlet line shape with a line width around 1.0 mT and an apparent g-value of 2.0044. In this work, we seek information on the exact chemical nature of the radiation-induced free radicals underlying the signal. This knowledge may provide insights into the reason for the discrepancy in the stabilities of the two RIS signals and help develop strategies for stabilizing the radicals in nails or devising methods for restoring the radicals after decay. In this work an analysis of high field (94 GHz and 240 GHz) EPR spectra of the RIS using quantum chemical calculations, the oxidation-reduction properties and the pH dependence of the signal intensities are used to show that spectroscopic and chemical properties of the RIS are consistent with a semiquinone-type radical underlying the RIS. It has been suggested that semiquinone radicals formed on trace amounts of melanin in nails are the basis for the RIS signals. However, based on the quantum chemical calculations and chemical properties of the RIS, it is likely that the radicals underlying this signal are generated from the radiolysis of L-3,4-dihydroxyphenylalanine (DOPA) amino acids in the keratin proteins. These DOPA amino acids are likely formed from the exogenous oxidation of tyrosine in keratin by the oxygen from the air prior to irradiation. We show that these DOPA amino acids can work as radical traps, capturing the highly reactive and unstable sulfur

Chemical chaperones reduce ionizing radiation-induced endoplasmic reticulum stress and cell death in IEC-6 cells

Energy Technology Data Exchange (ETDEWEB)

Lee, Eun Sang; Lee, Hae-June; Lee, Yoon-Jin [Division of Radiation Effects, Korea Institute of Radiological and Medical Sciences, Seoul 139-706 (Korea, Republic of); Jeong, Jae-Hoon [Division of Radiotherapy, Korea Institute of Radiological and Medical Sciences, Seoul 139-706 (Korea, Republic of); Kang, Seongman [Division of Life Sciences, Korea University, Seoul 136-701 (Korea, Republic of); Lim, Young-Bin, E-mail: yblim@kirams.re.kr [Division of Radiation Effects, Korea Institute of Radiological and Medical Sciences, Seoul 139-706 (Korea, Republic of)

2014-07-25

Highlights: • UPR activation precedes caspase activation in irradiated IEC-6 cells. • Chemical ER stress inducers radiosensitize IEC-6 cells. • siRNAs that targeted ER stress responses ameliorate IR-induced cell death. • Chemical chaperons prevent cell death in irradiated IEC-6 cells. - Abstract: Radiotherapy, which is one of the most effective approaches to the treatment of various cancers, plays an important role in malignant cell eradication in the pelvic area and abdomen. However, it also generates some degree of intestinal injury. Apoptosis in the intestinal epithelium is the primary pathological factor that initiates radiation-induced intestinal injury, but the mechanism by which ionizing radiation (IR) induces apoptosis in the intestinal epithelium is not clearly understood. Recently, IR has been shown to induce endoplasmic reticulum (ER) stress, thereby activating the unfolded protein response (UPR) signaling pathway in intestinal epithelial cells. However, the consequences of the IR-induced activation of the UPR signaling pathway on radiosensitivity in intestinal epithelial cells remain to be determined. In this study, we investigated the role of ER stress responses in IR-induced intestinal epithelial cell death. We show that chemical ER stress inducers, such as tunicamycin or thapsigargin, enhanced IR-induced caspase 3 activation and DNA fragmentation in intestinal epithelial cells. Knockdown of Xbp1 or Atf6 with small interfering RNA inhibited IR-induced caspase 3 activation. Treatment with chemical chaperones prevented ER stress and subsequent apoptosis in IR-exposed intestinal epithelial cells. Our results suggest a pro-apoptotic role of ER stress in IR-exposed intestinal epithelial cells. Furthermore, inhibiting ER stress may be an effective strategy to prevent IR-induced intestinal injury.

Radiological equivalent of chemical pollutants

International Nuclear Information System (INIS)

Medina, V.O.

1982-01-01

The development of the peaceful uses of nuclear energy has caused continued effort toward public safety through radiation health protection measures and nuclear management practices. However, concern has not been focused on the development specifically in the operation of chemical pestrochemical industries as well as other industrial processes brought about by technological advancements. This article presents the comparison of the risk of radiation and chemicals. The methods used for comparing the risks of late effects of radiation and chemicals are considered at three levels. (a) as a frame of reference to give an impression of resolving power of biological tests; (b) as methods to quantify risks; (c) as instruments for an epidemiological survey of human populations. There are marked dissimilarities between chemicals and radiation and efforts to interpret chemical activity may not be achieved. Applicability of the concept of rad equivalence has many restrictions and as pointed out this approach is not an established one. (RTD)

Radiation hazards and their effects

International Nuclear Information System (INIS)

Lunu, Shyam; Kumar, Hemant; Joshi, Pankaj Kumar; Songara, Venkteshwer

2012-01-01

Radiation can be classified into ionizing radiation and non-ionizing radiation, based on whether it is capable of ionizing atoms and breaking chemical bonds. Ultraviolet and higher frequency such as X-rays, gamma rays are ionizing. These pose their own special hazards. Non ionizing radiation is associated with two major potential hazards. i.e. electrical and biological. Additionally includes electric current caused by radiation can generate sparks and create a fire or explosive hazards. Strong radiation can induce current capable of delivering an electric shock. Extremely high power electromagnetic radiation can cause electric currents strong enough to create sparks when an induced voltage exceeds the breakdown voltage of surrounding mediums. A 2009 study at the University of Basal in Switzerland found that intermitted exposure of human cells to a 50 Hz electromagnetic field at a flux density of 10 Gy induced a slight but significant increase of DNA fragmentation in the comet assay. Mobile phones radiation and health concerns have been raised, especially following the enormous increase in the use of wireless mobile telephony throughout the world. Mobile phones use electromagnetic radiation in the microwaves range and some believes this may be harmful to human health. (author)

Radiation-chemical behaviour of actinides in extraction systems

International Nuclear Information System (INIS)

Vladimirova, M.V.; Fedoseev, D.A.; Bojkova, I.A.; Milovanova, A.S.

1987-01-01

Radiation-chemical behaviour of Pu(4) in γ-irradiated triisoamyl phosphate (TIAP) solutions in n-dodecane with metal concentration of 9.5x10 -3 mol/l is investigated by spectrophotometric and extraction methods within the interval of γ-irradiation absorbed dose values from 1.5x10 4 to 1.0x10 5 Gy. Absorption spectra of Pu(4) complexes with TIAP and diisoamylphosphoric acid (DIAPA) are taken for the first time and their extinction molar coefficients (e.m.c.) are determined. Apparent stability constants of Pu(4) complexes with DIAPA with molar ratio of acid to metal of 1:1 and 2:1 are determined. It is as certained, that in the result of organic solution γ-irradiation Pu(4) does not change its valent state, but forms complexes with DIAPA. Radiation-chemical yield of these complexes formation G D practically does not differ from G D for Pu(4) dibutylphosphate complexes and makes up 1.0±0.2 molec./100 eV. It is shown, that coefficients of Pu(4) distribution between γ-irradiated TIAP solutions in n-dodecane and HNO 3 aqueous solutions (0.1 ml/l) linearly increase with E γ growth. Absorption spectrum configuration and e.m.c. values of Pu(4) organic solutions after fourfold re-extraction testify to the fact, that nonextractable Pu(4) constitutes complexes with DIAPA with molar ratio of acid to metal of 1:1 and 2:1

Radiation effects on cell membranes

International Nuclear Information System (INIS)

Koeteles, G.J.

1982-01-01

The recent developments in the field of membrane biology of eukaryotic cells result in revival of relevant radiobiological studies. The spatial relations and chemical nature of membrane components provide rather sensitive targets. Experimental data are presented concerning the effects of relatively low doses of X-irradiation and low concentration of tritiated water (HTO) on various receptor functions - concanavalin A, cationized ferritin, poliovirus - of plasma membranes of animal and human cells which point to early and temporary disturbances of the composite structures and functions of membranes. References are given to the multifold roles of radiationinduced membrane phenomena on the development and regeneration of radiation injuries. (orig.)

Radiation effects on cell membranes

Energy Technology Data Exchange (ETDEWEB)

Koeteles, G.J.

1982-11-01

The recent developments in the field of membrane biology of eukaryotic cells result in revival of relevant radiobiological studies. The spatial relations and chemical nature of membrane components provide rather sensitive targets. Experimental data are presented concerning the effects of relatively low doses of X-irradiation and low concentration of tritiated water (HTO) on various receptor functions - concanavalin A, cationized ferritin, poliovirus - of plasma membranes of animal and human cells which point to early and temporary disturbances of the composite structures and functions of membranes. References are given to the multifold roles of radiationinduced membrane phenomena on the development and regeneration of radiation injuries.

The radiation protection effects of TMG to the embryonic effects on the organogenesis stage in ICR mice

International Nuclear Information System (INIS)

Santokuya, Takumi; Gu, Yeunhwa; Suzuki, Ikukatsu; Hasegawa, Takeo; Yamamoto, Youichi; Iwasa, Toshihiro; Yanagisawa, Takaharu

1999-01-01

The Organogenesis stage is the most important from the viewpoint of ionizing protection. Many physical and chemical agents in the environment can effect an embryo. Fetal deaths were classified as Preimplantation, Embryonic and Fetal. We studied an excuse as a radio protective agent of the high malformation of the sensitivity most by using TMG to the radiation. This study aimed at obtaining the information to provide it for the fetus' protection to the various environmental radiations. As for Preimplantation death, there was a statistical difference the 2.0Gy Group in comparison with the control group (p<0.05). Embryonic death, a statistical difference was recognized as in all the treatment groups (p<0.001). But, as for the TMG+radiation group, Malformation rate decreased to 1/2. As for Fetal body weight, a statistical difference was recognized in radiation group, the radiation+TMG infusion group chisels for medical use (p<0.05). Therefore, TMG protecting effect to the radiation was made clear by this research

A study of the direct effects of ionising and far ultraviolet radiation on nucleic acids

International Nuclear Information System (INIS)

Shaw, A.A.

1987-03-01

This thesis reports the results of a study of the direct effects of gamma and far UV radiation on nucleic acid model systems. For the gamma study, frozen aqueous solutions of 2'-deoxyribonucleosides were chosen as the model systems which best mimic possible radiation chemical events via the direct effects occuring in DNA in vivo. In Chapter I, we report and discuss the results of the study of the direct effects of gamma radiation on thymidine including the isolation and identification of the chemical modifications induced, and describe experiments designed to probe the mechanisms involved in their formation. In Chapters II and III, we extend the study to other 2'-deoxyribo-nucleosides, 2'-deoxycytidine and 2'-deoxyadenosine. Chapter IV presents the results of the study of the direct effects of far UV light on thymidine, a project designed to complement the gamma study and hopefully to bring additional insight into the mechanisms of formation of those products common to both radiation energies. In particular, the mechanisms of the formation of the spore photoproduct, a lesion known to be formed in DNA in vivo, have been elucidated. The study of the direct effects of gamma radiation on thymidine and 2'-deoxycytidine revealed the formation of several new products. Chapter V reports an analysis of the configurational and conformational properties of these molecules. (author)

Animal experiment studies on biological and chemical radiation protection - the combined effects of serotonin and erythropoletin

International Nuclear Information System (INIS)

Sasse, U.

1975-01-01

The influence of a prophylactic combination treatment with serotonin and erythropoietin on the inhibited erythropoiesis of whole-body irradiated mice (500 R) was studied. Both erythropoietin and serotonin turned out to compensate the radiation-induced inhibition of the formation rate for erythrocytes to a small extent. However, only the enhancement of erythropoiesis due to serotonin indicated significant values. Yet the combined application of the named substances yielded a distinct and significant effect in radiation protection which even exceeded the simple addition of the protective effect yielded by serotonin and erythropoietin alone. But despite of this considerable success the radiation damage in the erythropoietic system was not even half compensated for. (orig./MG) [de

Application of large radiation sources in chemical processing industry

International Nuclear Information System (INIS)

Krishnamurthy, K.

1977-01-01

Large radiation sources and their application in chemical processing industry are described. A reference has also been made to the present developments in this field in India. Radioactive sources, notably 60 Co, are employed in production of wood-plastic and concrete-polymer composites, vulcanised rubbers, polymers, sulfochlorinated paraffin hydrocarbons and in a number of other applications which require deep penetration and high reliability of source. Machine sources of electrons are used in production of heat shrinkable plastics, insulation materials for cables, curing of paints etc. Radiation sources have also been used for sewage hygienisation. As for the scene in India, 60 Co sources, gamma chambers and batch irradiators are manufactured. A list of the on-going R and D projects and organisations engaged in research in this field is given. (M.G.B.)

Evaluation Of Yield And Chemical Properties Of Some Faba Bean (Vicia FABA L.) Mutants Induced By GAMMA Radiation And Ethyl Methane Sulphonate

International Nuclear Information System (INIS)

Sallam, E.M.; Nasr, E.H.; Attia, Z.M.; Shawki, H.A.

2013-01-01

This investigation aims to study the effect of physical and chemical mutagens on the yield and chemical properties as well as amino acids composition of defatted faba bean (Vicia faba L.) seeds meal as a control (Giza 2) compared with mutants produced by gamma radiation and ethyl methane sulphonate (EMS). Also, the functional properties of these samples were determined. The results indicated high differences between mutation for seed yield and its components than the untreated samples. In addition, radiation mutation of faba bean seeds showed slight increase in protein content as the main constituent of faba bean seeds as well as total oil percentages in some mutant of these seeds in return of decreasing in total carbohydrate. Furthermore, radiation mutation had detectable effects on the total amino acids contents of faba bean seeds meal which had a higher percentages on essential amino acids (EAA) and non-essential amino acids (NEAA) and mutant 3 was the highest values of EAA and NEAA as compared to the control. On the other hand, radiation mutation improved the protein functional properties of some mutant of faba bean meal flour than the other mutant samples as compared to local commercial variety

Biological effects of ionizing radiation

International Nuclear Information System (INIS)

Heribanova, A.

1995-01-01

The basic principles and pathways of effects of ionizing radiation on living organisms and cells are outlined. The following topics are covered: effects of radiation on living matter (direct effects, radical or indirect effects, dual radiation action, and molecular biological theories); effects of radiation on cells and tissues (cell depletion, changes in the cytogenetic information, reparation mechanisms), dose-response relationship (deterministic effects, stochastic effects), and the effects of radiation on man (acute radiation sickness, acute local changes, fetus injuries, non-tumorous late injuries, malignant tumors, genetic changes). (P.A.). 3 tabs., 2 figs., 5 refs

Synergistic effects in radiation-induced particle ejection from solid surfaces

International Nuclear Information System (INIS)

Itoh, Noriaki

1990-01-01

A description is given on radiation-induced particle ejection from solid surfaces, emphasizing synergistic effects arising from multi-species particle irradiation and from irradiation under complex environments. First, it is pointed out that synergisms can be treated by introducing the effects of material modification on radiation-induced particle ejection. As examples of the effects of surface modification on the sputtering induced by elastic encounters, sputtering of alloys and chemical sputtering of graphite are briefly discussed. Then the particle ejection induced by electronic encounters is explained emphasizing the difference in the behaviors from materials to materials. The possible synergistic effects of electronic and elastic encounters are also described. Lastly, we point out the importance of understanding the elementary processes of material-particle interaction and of developing computer codes describing material behaviors under irradiation. (author)

Radiation degradation and the consequent decrease in the efficacy of some dilute chemical decontaminant formulations

Energy Technology Data Exchange (ETDEWEB)

Kamal Kishore; Dey, G.R.; Naik, D.B.; Moorthy, P.N. [Applied Chemistry Division, Bhabha Atomic Research Centre, Trombay, Mumbai-400 085 (India)

1998-12-31

Constituents of dilute chemical decontaminant formulations such as ascorbic acid, EDTA, picolinic acid (PA) and 2,6-pyridine dicarboxylic acid (PDCA), also known as dipicolinic acid, are highly reactive with primary species produced from water radiolysis. Picolinic acid and PDCA however, are less sensitive to radiation dose due to their aromatic nature. They also help in protecting ascorbic acid when in a mixture. The efficacy for dissolution of magnetite was found to reduce drastically on irradiation in the case of EDTA/oxalic acid/citric acid while it was unaffected in the case of picolinic acid/ascorbic acid. In the case of EDTA/ascorbic acid/citric acid or PDCA/ascorbic acid formulations, there was only a marginal effect of radiation on the efficacy of the formulations. (author)

Ionising radiation effects on food packaging

International Nuclear Information System (INIS)

Ragni, P.; Segre, A. L.; Capitani, D.; Danesi, P.R.

2001-01-01

The main aim of any food irradiation treatment is to guarantee the best safe quality of the products, reducing the spreading risk ( c ross-contamination ) for several food-associated diseases. Actually, over 40 countries provide clearances for the treatment of about 45 different types of foodstuffs. EU has to homogenise the situation within the associated States. With the European directive 1999/2/EC Italy, as other EU countries, already has brought into force their regulations to comply. The current Italian regulation on irradiation treatment of foodstuffs is referred since 1996 as follows: a) potatoes, onions and garlic; b) spices, herbs and condiments microbial. The new (April 2001) Italian law allows the possibility to ask for special permission of treatment for other foodstuff which is possible to treat in other E.U. countries. Large majority of foods are submitted to irradiation treatment after they have been packaged. In Dutch cases the study of radiation effects on the package becomes crucial, also because polymeric materials may be affected by ionizing radiation. We performed our studies on several materials employed in food packaging, with a particular care to the role of anti-oxidant additives present in food packaging materials. The attention is pointed on the possible chemical-physical effects induced by radiation on foodstuff packaging. After irradiation in plastic materials two main effects may occur: degradation and cross-linking. The result depending on the comparative rates of the two actions. This kind of information was successfully obtained using NMR methods on a large number of polymers effectively used for the food packaging procedures

Effect of gamma radiation on graphite – PTFE dry lubrication system

International Nuclear Information System (INIS)

Singh, Sachin; Tyagi, Mukti; Seshadri, Geetha; Tyagi, Ajay Kumar; Varshney, Lalit

2017-01-01

An effect of gamma radiation on lubrication behavior of graphite -PTFE dry lubrication system has been studied using (TR-TW-30L) tribometer with thrust washer attachment in plane contact. Different compositions of graphite and PTFE were prepared and irradiated by gamma rays. Gamma radiation exposure significantly improves the tribological properties indicated by decrease in coefficient of friction and wear properties of graphite -PTFE dry lubrication system. SEM and XRD analysis confirm the physico-chemical modification of graphite-PTFE on gamma radiation exposure leading to a novel dry lubrication system with good slip and anti friction properties. - Highlights: • Novel dry lubrication system of graphite -PTFE using gamma radiation. • Gamma radiation processing. • Reduction in coefficient of friction, frictional torque and wear loss of developed dry lubrication system.

Health effects of occupational exposure to hazardous chemicals: a comparative assessment with notes on ionizing radiation. Executive summary. Vol. 1

International Nuclear Information System (INIS)

Zanetos, M.A.; Warling, J.C.; Marsh, G.M.

1983-09-01

This three-part report provides quantitative estimates of the risk of cancer and other diseases among persons exposed to hazardous substances in the workplace. The risk estimates presented are based on a comprehensive review of recent epidemiologic studies. Primary emphasis was placed on studies of workers exposed to hazardous chemicals under conditions typical of a given industry over a working lifetime. Despite finding over 100 chemicals associated with increased incidence of disease, convincing dose-response trends existed for only a few. Although there were notable exceptions (arsenic, asbestos, PAH's, etc.), it was generally impossible to estimate risk-per-unit of dose in a manner analogous to calculations which exist for radiation exposure. The principal reason for this is the lack of adequate environmental monitoring data for the specific chemicals, locations, and time periods needed to estimate individual cumulative doses. In addition to analyzing risk in terms of increased incidence of specific diseases, we also examined life expectancy and years of life lost due to cancer in four selected occupational groups via a life table model which allowed for competing risks. The resulting estimates indicated that the overall life expectancy of these groups was generally greater than that of the general population but that the workers suffered greater loss of life expectancy (LLE) due to cancer than their counterparts in the general population. Published estimates of LLE due to radiation induced cancer indicate that at doses of less than or equal to 0.5 rem/y, radiation workers are projected to suffer less LLE than any of the four non-nuclear cohorts examined. At 5 rem/y (the MPD) or higher, LLE may be greater than one or more of the cohorts examined. This is Volume I of a three volume series. 12 references

Atoms, radiation, and radiation protection

International Nuclear Information System (INIS)

Turner, J.E.

1986-01-01

This book describes basic atomic and nuclear structure, the physical processes that result in the emission of ionizing radiations, and external and internal radiation protection criteria, standards, and practices from the standpoint of their underlying physical and biological basis. The sources and properties of ionizing radiation-charged particles, photons, and neutrons-and their interactions with matter are discussed in detail. The underlying physical principles of radiation detection and systems for radiation dosimetry are presented. Topics considered include atomic physics and radiation; atomic structure and radiation; the nucleus and nuclear radiation; interaction of heavy charged particles with matter; interaction of beta particles with matter; phenomena associated with charged-particle tracks; interaction of photons with matter; neutrons, fission and criticality; methods of radiation detection; radiation dosimetry; chemical and biological effects of radiation; radiation protection criteria and standards; external radiation protection; and internal dosimetry and radiation protection

Study of the radiation effects on nucleic acids and related compounds. Annual progress report, August 15, 1974--August 14, 1975

International Nuclear Information System (INIS)

Wang, S.Y.

1975-01-01

Interest is being centered on the chemical and physical nature of radiation-induced lesions to nucleic acids and their components. These investigations have revealed the enormous complexity of chemical events in these systems and the possible degradation of nucleic acids by strand breakage. Therefore, work in the ionizing radiation of DNA and its components has proceeded along a dual course. For chemical studies, our prime concern is the stepwise isolation and identification of the radiation products of derivatives of pyrimidines and the study of the actual mechanisms of their formation. For biological studies, H. influenzae cells, the Chinese hamster V79B-1 cell line, and the Dunn osteosarcoma lung colony system were used. During the last year, the method of synthesis of 5-hydroperoxymethyluracil (T/sub α/OOH) was greatly improved. Large-scale preparation of 5-hydroxy-6-hydroperoxy-5,6-dihydrothymine (T 6 OOH) were carried out in order to study the action of T 6 OOH on neighboring bases, glycosidic bond-breakage, cell mutagenesis, chromosomal aberrations, and possible synergistic effects on x radiation. These results allow one to relate radiobiological effects with radiation chemical changes in DNA

The late biological effects of ionizing radiation

Energy Technology Data Exchange (ETDEWEB)

NONE

1978-06-15

surveillance. As far as medical exposure is concerned, current practices involving radiation exposure seems well justified in most of the cases, except some where radiation is used for diagnostic purposes of benign disorders. Cytological, histological and physiological studies were reported on experimental animals, apart from cancer induction, on the effect of neonatal exposure and effects on central nervous system. These provided basic data by which human data can be interpreted and analysed. Several novel approaches were reported for prediction of late effects, e.g. DNA repair capability, and some cytogenetic and physiological parameters which are expected to be of practical merit in future. The dose-effect relationship, by which human risk estimates at low doses are derived by extrapolation, was another topic of lively discussion. Several new models based on theoretical analysis or experimental data were proposed and compared with the available human and animal data. Although the validity of these awaits further research, some shed a new light on the problems of extrapolation. Radiation effects in practice are complicated by other environmental factor;, such chemical pollutants which may be additional causal agents. The importance of theoretical approach for prediction of such combined effects was stressed. Of interest was the combined effect of smoking and radon-222 in lung cancer induction. Lung cancer incidence was significantly elevated by combination of the two in the rat, which was also substantiated by the observation in Hiroshima-Nagasaki study where incidence of lung cancer in the smoking population was shown to be higher than the non-smoking population, suggesting synergistic effects of radiation and smoking. This meeting brought together people with a remarkably wide range of interests including the practicalities of radiological protection, epidemiology, medical practices and theoretical and experimental radiobiology. It was stressed that research co

Fundamental radiation effect on polymers energy transfer from radiation to polymer

International Nuclear Information System (INIS)

Seguchi, T.

2007-01-01

Polymer modification as cross-link, chain scission, and graft-polymerization by radiation is initiated by the quantum energy transferred from radiation to polymers. The active species for chemical reactions are produced through ionization or activation of polymer molecules for any radiation source. The energy transfer occurs mainly by ionic interaction between radiation and polymer molecule, and the contribution from the collision interaction is miner. The radiation of electromagnetic wave as X-ray or γ-ray generates the energetic electron which induces ionic interaction with polymer molecule. The energy loss profile along the penetration to polymer material is much different among the radiation sources of EB, γ-ray, and ion beams in the macroscopic mechanism. In this article, the behavior of single event, that is, the event induced by one electron, γ-ray, ion, and neutron is described by the macroscopic mechanism and by the microscopic mechanism. (authors)

Enhancement of chemically induced reactive oxygen species production and DNA damage in human SH-SY5Y neuroblastoma cells by 872 MHz radiofrequency radiation

Energy Technology Data Exchange (ETDEWEB)

Luukkonen, Jukka [Department of Environmental Science, University of Kuopio, Bioteknia 2, P.O. Box 1627, FI-70211 Kuopio (Finland)], E-mail: Jukka.Luukkonen@uku.fi; Hakulinen, Pasi; Maeki-Paakkanen, Jorma [Department of Environmental Health, National Public Health Institute, P.O. Box 95, FI-70701 Kuopio (Finland); Juutilainen, Jukka; Naarala, Jonne [Department of Environmental Science, University of Kuopio, Bioteknia 2, P.O. Box 1627, FI-70211 Kuopio (Finland)

2009-03-09

The objective of the study was to investigate effects of 872 MHz radiofrequency (RF) radiation on intracellular reactive oxygen species (ROS) production and DNA damage at a relatively high SAR value (5 W/kg). The experiments also involved combined exposure to RF radiation and menadione, a chemical inducing intracellular ROS production and DNA damage. The production of ROS was measured using the fluorescent probe dichlorofluorescein and DNA damage was evaluated by the Comet assay. Human SH-SY5Y neuroblastoma cells were exposed to RF radiation for 1 h with or without menadione. Control cultures were sham exposed. Both continuous waves (CW) and a pulsed signal similar to that used in global system for mobile communications (GSM) mobile phones were used. Exposure to the CW RF radiation increased DNA breakage (p < 0.01) in comparison to the cells exposed only to menadione. Comparison of the same groups also showed that ROS level was higher in cells exposed to CW RF radiation at 30 and 60 min after the end of exposure (p < 0.05 and p < 0.01, respectively). No effects of the GSM signal were seen on either ROS production or DNA damage. The results of the present study suggest that 872 MHz CW RF radiation at 5 W/kg might enhance chemically induced ROS production and thus cause secondary DNA damage. However, there is no known mechanism that would explain such effects from CW RF radiation but not from GSM modulated RF radiation at identical SAR.

Enhancement of chemically induced reactive oxygen species production and DNA damage in human SH-SY5Y neuroblastoma cells by 872 MHz radiofrequency radiation

International Nuclear Information System (INIS)

Luukkonen, Jukka; Hakulinen, Pasi; Maeki-Paakkanen, Jorma; Juutilainen, Jukka; Naarala, Jonne

2009-01-01

The objective of the study was to investigate effects of 872 MHz radiofrequency (RF) radiation on intracellular reactive oxygen species (ROS) production and DNA damage at a relatively high SAR value (5 W/kg). The experiments also involved combined exposure to RF radiation and menadione, a chemical inducing intracellular ROS production and DNA damage. The production of ROS was measured using the fluorescent probe dichlorofluorescein and DNA damage was evaluated by the Comet assay. Human SH-SY5Y neuroblastoma cells were exposed to RF radiation for 1 h with or without menadione. Control cultures were sham exposed. Both continuous waves (CW) and a pulsed signal similar to that used in global system for mobile communications (GSM) mobile phones were used. Exposure to the CW RF radiation increased DNA breakage (p < 0.01) in comparison to the cells exposed only to menadione. Comparison of the same groups also showed that ROS level was higher in cells exposed to CW RF radiation at 30 and 60 min after the end of exposure (p < 0.05 and p < 0.01, respectively). No effects of the GSM signal were seen on either ROS production or DNA damage. The results of the present study suggest that 872 MHz CW RF radiation at 5 W/kg might enhance chemically induced ROS production and thus cause secondary DNA damage. However, there is no known mechanism that would explain such effects from CW RF radiation but not from GSM modulated RF radiation at identical SAR

Long-term biological effects induced by ionizing radiation--implications for dose mediated risk.

Science.gov (United States)

Miron, S D; Astărăstoae, V

2014-01-01

Ionizing radiations are considered to be risk agents that are responsible for the effects on interaction with living matter. The occurring biological effects are due to various factors such as: dose, type of radiation, exposure time, type of biological tissue, health condition and the age of the person exposed. The mechanisms involved in the direct modifications of nuclear DNA and mitochondrial DNA are reviewed. Classical target theory of energy deposition in the nucleus that causes DNA damages, in particular DNA double-strand breaks and that explanation of the biological consequences of ionizing radiation exposure is a paradigm in radiobiology. Recent experimental evidences have demonstrated the existence of a molecular mechanism that explains the non-targeted effects of ionizing radiation exposure. Among these novel data, genomic instability and a variety of bystander effects are discussed here. Those bystander effects of ionizing radiation are fulfilled by cellular communication systems that give rise to non-targeted effects in the neighboring non irradiated cells. This paper provides also a commentary on the synergistic effects induced by the co-exposures to ionizing radiation and various physical agents such as electromagnetic fields and the co-exposures to ionizing radiation and chemical environmental contaminants such as metals. The biological effects of multiple stressors on genomic instability and bystander effects are also discussed. Moreover, a brief presentation of the methods used to characterize cyto- and genotoxic damages is offered.

Treatment of spices with ionizing radiation - chemical, organoleptical, microbiological and toxicological analyses. Pt. 2

International Nuclear Information System (INIS)

Schuettler, C.; Boegl, W.

1984-09-01

In the present second part of a study of the relevant literature the results of tests on 14 radiation treated spices and 2 radiation treated spice-mixtures were evaluated. The tests in this part contain mainly toxicological but also chemical and sensorial analyses. Most of the spices were treated with gamma radiation from cobalt-60 sources with doses between 80 Gy and 60 kGy. This part contains a cumulated subject index for part 1 and part 2. (orig./AJ) [de

BYSTANDER EFFECTS GENOMIC INSTABILITY, ADAPTIVE RESPONSE AND CANCER RISK ASSESSMENT FOR RADIAION AND CHEMICAL EXPOSURES

Science.gov (United States)

BYSTANDER EFFECTS, GENOMIC INSTABILITY, ADAPTIVE RESPONSE AND CANCER RISK ASSESSMENT FOR RADIATION AND CHEMICAL EXPOSURESR. Julian PrestonEnvironmental Carcinogenesis Division, U.S. Environmental Protection Agency, Research Triangle Park, N.C. 27711, USAThere ...

Isoparaffin diluents for tri-n-butyl phosphate. Chemical, radiation-chemical stability, effect on solvent extraction of tetravalet plutonium and thorium

International Nuclear Information System (INIS)

Renard, Eh.V.; Pyatibratov, Yu.P.; Neumoev, N.V.

1988-01-01

45-90% conversion degree of n-paraffin into branched isoparaffin with mono- and dimethyl structure is achieved by means of catalytic hydroisomerization of n-paraffin raw material in reactor with alumoplatinum catalyser. Isoparaffin (99%) concentrates with constant molecular mass from iso-C 10 to iso-C 15 are produced of a batch of deeply isomerized n-paraffins. Plutonium and thorum nitrate solubility in 30% TBP solutions in iso-paraffins (iso-paraffin mixtures with similar C atom number) increases with the reduction of iso-paraffin molecular mass; system with 30% TBP in isodecane mixture is practically not stratified (∼ 104 g Pu/l, 22-25 deg C). By the main requirements to diluents for radiochemical extraction operations, including density, viscosity, boiling point flashed and freezines, chemical and radiation stability, radioruthenium and radiozirconium confinement systems, synthetic isoparaffin-containing solvents are as good as n-paraffins

Radiation effects on foodstuffs. Pt. 1

International Nuclear Information System (INIS)

Kuehl, M.; Boegl, W.; Stockhausen, K.

1980-01-01

In this report, results of irradiation experiments at about 30 foodstuffs are compiled and analyzed. The only objective was to obtain a survey of the chemical changes of irradiated foodstuffs; therefore, neither microbiological nor toxicological aspects were considered. The results were taken from the original publications and compiled in a type of dictionary of foodstuffs listing all relevant data for each substance (foodstuff, irradiation conditions, investigation procedures, results etc.) in a defined order. The main radiation source was Co 60, and the doses ranged between 0,006 and 10 Mrad. The investigations were related not only to the effects of irradiation (in some cases using different absorbed doses per foodstuff), but also to the effects of storage after irradiation (for 16 foodstuffs) and the effects of temperature (for 3 foodstuffs). (orig./MG) [de

Gamma radiation and temperature influence on the chemical effect produced by isomeric transition in the telluric acid

International Nuclear Information System (INIS)

Muriel G, M.

1976-01-01

When the gamma radiation due to the isomeric transition is internally converted an autoionization is produced. For atoms with a high atomic number this autoionization can be a large one and produce a fragmentation in a molecule. In the specific case of the solid state these fragments remain trapped in different places of the crystalline system. This can be considered as chemical change in the original molecule. These damages produced by the nuclear transformation can be measured by different methods: heating, gamma rays, pressure, etc. In this work the results of an experimental measurement of the behavior of the crystalline telluric acid molecule fragments under gamma radiation (0 to 20 Mrads) with controlled temperature of 2 0 C (-196 0 C to 50 0 C) it is presented. It was observed that the values of the mentioned behavior vary rapidly at first for relatively low doses and that for larger doses these values remained constant. Besides with a lower temperature these variation are progressively lower. (author)

Calculation and construction of radioisotopic radiation chemical installations. [Book (reference text); In Russian]. Raschet i konstruirovanie radioizotopnykh radiatsionno-khimicheskikh ustanovok

Energy Technology Data Exchange (ETDEWEB)

Kulisha, E E

1975-01-01

A discussion is given of the development of radiation sources and the uses of gamma sources. The chemical and radiation characteristics of the sources are considered, and the fabrication methods are described for different types of sources used for radiation-induced chemical processes in condensed phase and in two-phase systems. Technological dosimetry, industrial and radiation safety, and economic aspects of gamma sources are examined. The text serves as a reference for physicists, chemistry technologists, engineers, and other scientific workers.

Effect of temperature and gamma radiation on pupae of tenebrio molitor LINNE

International Nuclear Information System (INIS)

Arthur, Valter; Arthur, Paula Bergamin

2001-01-01

Among insect pests of grains and stored products Tenebrio molitor (Coleoptera : Tenebriodae) is one of the species of insects that attack flours, corn meal, rations, macaronis and damages grains. Chemical treatment is not always the remedy because it causes problems of residue on treated food. One alternative method of control is the application of ionization radiations as suggested by Hunter, some others recommended the use of gamma radiation to control insects that attack grains and stored products. Arthur and Wiendl reported that the sterilizing dose to adults of this species is 60 Gy. The effect of temperature after and before the gamma radiation to Laemophleous spp. Zabrotes subfasciatus and Sitophilus oryzae has been studied by many workers. Since no study with radiological effects in combination with temperature is reported on T. molitor, research work has been carried out to study the synergistic effects of gamma radiation and temperature on pupae of this insect

Comparative analysis of changes in protein and lipid metabolism, lipid peroxidation, and hemostasis under the effects of polychlorinated dibenzo-p-dioxins and radiation

International Nuclear Information System (INIS)

Kuntsevich, A.D.; Baulin, S.I.; Golovkov, V.F.; Rembovskii, V.R.; Smirnova, L.A.; Troshkin, N.M.

1994-01-01

Polychlorinated dibenzo-p-dioxins (PCDD) and ionizing radiation are among the most hazardous environmental factors causing ecological catastrophes and mass afflications in various accidents involving nuclear power plants and chemical industrial enterprises. The authors previously established that the simultaneous action of a toxic dose of PCDD and ionizing radiation increases the combined toxic effect. The effects of these chemical and physical factors were superadditive (the biological potentiation effect). Here, the authors compare the effects of PCDD and irradiation on protein and lipid metabolism, lipid peroxidation, and hemostasis in order to learn more about biochemical mechanisms mediating the potentiation effect. The experimental evidence suggests that PCDD can modify the biological effects of ionizing radiation through the generation of free radicals and activation of the chain reactions of free-radical lipid peroxidation, such as the formation of peroxides or malonic dialdehyde. The toxic effects of PCDD and ionizing radiation are based on free-radical reactions and chemical pathology. In other words, the chemical and physical factors directly and selectively hit the same biological target, thereby increasing their combined toxic effects. The results can partially explain the observed potentiating effect of the combined action of ionizing radiation and PCDD on the body. This phenomenon is based on biochemical processes generating an abundance of products of lipid peroxidation and the decrease in the body's defenses caused by disorders in protein and lipid metabolism and blood coagulation

Inventory and systematization of data on radiation-chemical contamination of rivers running along Bryansk-Belarusian 'cesium spot'

International Nuclear Information System (INIS)

Germenchuk, M.G.; Zhukova, O.M.; Bakarykava, Zh.; Popova, E.; Gorbatova, G.

2005-01-01

Inventory and systematization of the data on radioactive-chemical contamination of rivers are made. Systematization of the data on chemical and radiation contamination component of rivers was made with using the index of integrated radiation-chemical surface waters contamination (IRCCI=WCI+RCI). Chemical contamination of surface water has been estimated using water contamination index (WCI). It constitutes an integrated magnitude considering ratios of six more significant pollutants to their maximum concentration limits. In dependence on WCI surface water can be attributed to one of seven classes: from 'clean' (with WCI≤1) to 'extremely dirty' (with WCI>10). At present for estimation of radioactive contamination of surface water only comparison with Republican permissible levels are used. But it is not enough for complex estimation of water quality because it does not enable to estimate the extent of radionuclide exceeding over their permissible levels. Therefore for estimation of radioactive pollution level, water radioactive contamination index (RCI) was applied. It is a sum of ratios of main radionuclide concentrations to their permissible levels. Application of RCI enabled to compare radioactive contamination before and after the Chernobyl accident. Application of the index of integrated radiation-chemical surface water contamination enabled to obtain the most complete and impartial estimate of surface water quality of some rivers. Retrospective estimation of the water quality shows that in 1990 surface waters of some rivers should be considered as belonging to more contaminated category of quality if radiation component would have been considered. (authors)

Physical chemical radiation effects in scintillator solutions content PPO and POPOP

International Nuclear Information System (INIS)

Fernandes Neto, Jose Mari; Hamada, Margarida Mizue; Duarte, Celina Lopes; Mesquita, Carlos Henrique de

2005-01-01

Samples containing PPO (1%, g/mL), diluted in toluene, were irradiated in a 60 Co irradiator (6.46 kGy/h) at different doses. The PPO concentration decay bi-exponentially with the dose, generating the degradation products: benzoic acid, benzamide and benzilic alcohol. The liquid scintillator system was not sensitive to the radiation damage until 20 kGy. Otherwise, the pulse height analysis showed that doses between 30 and 40 kGy generated significant loss of quality of the sensor (scintillating liquid) and the light yield was reduced in half with the dose of (34.04 ± 0.80) kGy. This value was confirmed by the photopeak position analysis that resulted in D1/2 = (31.7 ± 1.4) kGy. The transmittance, at 360 nm, of the irradiated solution decreased exponentially. The compartmental model using five compartments (fast decay PPO, slow decay PPO, benzamide, benzoic acid and benzilic alcohol) was satisfactory to explain the decay of the PPO in its degradation products as a function of the dose. The explanation coefficient r2 = 0.985636 demonstrates that the model was capable to explain 98.6% of the experimental variations. The energies involved in the chemical reactions were w = (0.239 ± 0.031) eV/damage (fast decay) and w (1.834 ± 0.301) eV/damage (slow decay). (author)

The biological effects of low doses of radiation: medical, biological and ecological aspects

International Nuclear Information System (INIS)

Gun-Aajav, T.; Ajnai, L.; Manlaijav, G.

2007-01-01

Full text: The results of recent studies show that low doses of radiation make many different structural and functional changes in a cell and these changes are preserved for a long time. This phenomenon is called as effects of low doses of radiation in biophysics, radiation biology and radiation medicine. The structural and functional changes depend on doses and this dependence has non-linear and bimodal behaviour. More detail, the radiation effect goes up and reaches its maximum (Low doses maximum) in low doses region, then it goes down and takes its stationary means (there is a negative effect in a few cases). With increases in doses and with further increases it goes up. It is established that low dose's maximum depends on physiological state of a biological object, radiation quality and dose rate. During the experiments another special date was established. This specialty is that many different physical and chemical factors are mutually connected and have synergetic behaviour. At present, researches are concentrating their attention on the following three directions: 1. Direct and indirect interaction of radiation's low doses: 2. Interpretation of its molecular mechanism, regulation of the positive effects and elaboration of ways o removing negative effects: 3. Application of the objective research results into practice. In conclusion the authors mention the current concepts on interpretation of low doses effect mechanism, forward their own views and emphasize the importance of considering low doses effects in researches of environmental radiation pollution, radiation medicine and radiation protection. (author)

Repair of human DNA: radiation and chemical damage in normal and xeroderma pigmentosum cells

International Nuclear Information System (INIS)

Regan, J.D.; Setlow, R.B.

1976-01-01

We present the experimental evidence we have gathered, using a particular assay for DNA repair in human cells, the photolysis of bromodeoxyuridine (BrdUrd) incorporated during repair. This assay characterizes the sequence of repair events that occur in human cells after radiation, both ultraviolet and ionizing, and permits an estimation of the size of the average repaired region after these physical insults to DNA. We will discuss chemical insults to DNA and attempt to liken the repair processes after chemical damages of various kinds to those repair processes that occur in human DNA after damage from physical agents. We will also show results indicating that, under certain conditions, repair events resembling those seen after uv-irradiation can be observed in normal human cells after ionizing radiation. Furthermore the XP cells, defective in the repair of uv-induced DNA damage, show defective repair of these uv-like DNA lesions induced by ionizing radiation

Impact of radiation treatment on chemical, biochemical and sensory properties, and microbiological quality of mackerel

Science.gov (United States)

Pinter, Nino; Maltar-Strmečki, Nadica; Kozačinski, Lidija; Njari, Bela; Cvrtila Fleck, Željka

2015-12-01

The effect of gamma radiation on shelf-life of mackerel (Scomber scombrus) was studied. Changes in raw fish stored at 4 °C were investigated simultaneously, by performing sensory evaluation, chemical analysis (pH value and NH3 concentration), and biochemical analyses of histamine concentration and microbiological quality. Analyses showed that preservation by gamma irradiation prolonged the freshness and sustainability without any unintended sensory changes. Furthermore, increasing the dose during the 10 days of storage considerably reduced the concentration of histamine, but only slightly reduced the concentration of ammonia (NH3). Bacterial examinations showed that gamma radiation decreased the total number of bacteria. Our results indicated that the shelf-life of mackerel stored at 4 °C can be prolonged by irradiation with a dose of 3 kGy.

Chemical protection from high LET radiation

International Nuclear Information System (INIS)

Ando, Koichi; Koike, Sachiko; Matsushita, Satoru; Kanai, Tatsuaki; Ohara, Hiroshi

1992-01-01

Radioprotection by WR151327 from high LET fast neutrons was investigated and compared with that from low LET radiation. Radiation damage in bone marrow, intestine, skin and leg length were all protected by a pretreatment with 400 mg/kg WR151327. Most prominent protection was observed for bone marrow, which gave a Dose Modifying Factor (DMF) of 2.2 against γ rays. Identical protection was observed between early and late radiation damage. WR151327 protected fast neutrons less efficiently than γ rays; 40% for bone marrow and 80% for skin leg. Pathological findings indicated that hyperplastic change in both dermis and epidermis associated with late skin shrinkage. Laser doppler flow-metry showed a good relationship between reduction of blood flow and late skin shrinkage. Irradiation of skin by heavy particle Carbon-12 indicated that skin shrinkage was modified by unirradiated surrounding normal tissues, which proposed a significant role of 'Volume Effect' in radiation damage. Tumor tissues were less protected by WR151327 than normal tissues. Dependence of radioprotection by WR151327 on tissue oxygen concentration is a probable reason to explain the difference between normal and tumor tissues. (author)

Chemical shift of U L3 edges in different uranium compounds obtained by X-ray absorption spectroscopy with synchrotron radiation

International Nuclear Information System (INIS)

Joseph, D.; Jha, S.N.; Nayak, C.; Bhattacharyya, D.; Babu, P. Venu

2014-01-01

Uranium L 3 X-ray absorption edge was measured in various compounds containing uranium in U 4+ , U 5+ and U 5+ oxidation states. The measurements have been carried out at the Energy Dispersive EXAFS beamline (BL-08) at INDUS-2 synchrotron radiation source at RRCAT, Indore. Energy shifts of ∼ 2-3 eV were observed for U L 3 edge in the U-compounds compared to their value in elemental U. The different chemical shifts observed for the compounds having the same oxidation state of the cation but different anions or ligands show the effect of different chemical environments surrounding the cations in determining their X-ray absorption edges in the above compounds. The above chemical effect has been quantitatively described by determining the effective charges on U cation in the above compounds. (author)

Introduction to radiation biology

International Nuclear Information System (INIS)

Uma Devi, P.; Satish Rao, B.S.; Nagarathnam, A.

2000-01-01

This book is arranged in a logical sequence, starting from radiation physics and radiation chemistry, followed by molecular, subcellular and cellular effects and going on to the level of organism. Topics covered include applied radiobiology like modifiers of radiosensitivity, predictive assay, health physics, human genetics and radiopharmaceuticals. The topics covered are : 1. Radiation Physics, 2. Detection and Measurement of Radiation, 3. Radiation Chemistry, 4. DNA Damage and Repair, 5. Chromosomal Aberrations and Gene Mutations, 6. Cellular Radiobiology 7. Acute Radiation Effects, 8. Delayed Effects of Radiation, 9. Biological Basis of Radiotherapy, 10. Chemical Modifiers of Radiosensitivity, 11. Hyperthermia, 12. High LET Radiations in Cancer, Therapy, 13. Predictive Assays, 14. Radiation Effects on Embryos, 15. Human Radiation Genetics, 16. Radiolabelled Compounds in Biology and Medicine and 17. Radiological Health

Effect of alpha and gamma radiation on the near-field chemistry and geochemistry of high-level waste packages

International Nuclear Information System (INIS)

Reed, D.T.

1985-12-01

Ionizing radiation can potentially alter geochemical and chemical processes in a geologic system. These effects can either enhance or reduce the performance of the waste package in a deep geologic repository. Current indications are that, in a repository located in basalt, ionizing radiation significantly affects geochemical/chemical processes but does not appear to significantly affect factors important to the long-term performance of the repository. The experimental results presented in this paper were obtained as part of an ongoing effort by the Basalt Waste Isolation Project to determine the effect of ionizing radiation on chemical and geochemical processes in the environment of the waste package. Gamma radiolysis experiments were done by subjecting samples of synthetic basalt groundwater in the presence of various waste package components (basalt/packing/low-carbon steel) to high levels of gamma radiation from a 60 Co source. Post-irradiation analysis was done on the gas, liquid, and solid components of the basalt system. The results obtained are important in evaluating waste package performance during the containment period. The effect of alpha radiation on the basalt groundwater system in the presence of waste package components is important in evaluating waste package performance during the isolation period. The experimental work in this area is in a very preliminary stage. Results from two experiments are reported. 9 refs., 4 figs., 7 tabs

Treatment of wastewater and sludge, and decomposition of endocrine disrupting chemicals with radiation

International Nuclear Information System (INIS)

Kudo, Hisaaki

2006-01-01

This country report describes the past and current research activities in Japan on radiation treatment of wastewater and sludge carried out by early 90s, and decomposition of endocrine disrupting chemicals that is going-on. (author)

Ionizing radiation effects in Brazilian grape tree wine

Energy Technology Data Exchange (ETDEWEB)

Harder, Marcia N.C.; Gutierrez, Érika M.R., E-mail: marcia.harder@fatec.sp.gov.br, E-mail: emrgutierrez@hotmail.com [Faculdade de Tecnologia de Piracicaba (FATEC), Piracicaba, SP (Brazil). Curso de Tecnologia em Alimentos. Dep. Roque Trevisan; Pires, Juliana A., E-mail: juliana.angelo@gmail.com [Instituto de Pesquisas Energéticas e Nucleares (IPEN/CNE-SP), São Paulo, SP (Brazil); Arthur, Valter; Silva, Lúcia C.A.S., E-mail: arthur@cena.usp.br, E-mail: lcasilva@cena.usp.br [Centro de Energia Nuclear na Agricultura (CENA/USP), Piracicaba, SP (Brazil)

2017-07-01

The aim of this work was to irradiate brazilian grape tree wines with gamma radiation (Co{sup 60}) to investigate the effect of radiation on its components and to create a new product for the superior quality fermented beverages market. For this wine was produced in an artisan way, but with all the care of hygiene and sanitation. The brazilian grape tree was fermented for five days and the wine was then filtered and stored in inert material containers then irradiated at 2.5 and 5 kGy doses. The samples were evaluated in relation to the radiation doses used. Physical and chemical analyzes of pH; total and volatile acidity; alcohol content; anthocyanins; tannins and colorimetry were performed. As a result, in most product analysis, had little effect on irradiation, except for anthocyanins and tannins. For this can be concluded that it is possible to develop a new fermented drink based on brazilian grape tree, according to the standards required by the legislation and that the irradiation at the dose of 5kGy was the sample that shown to have the most effect on the color because it was the one that degraded most molecules of anthocyanins and tannins. (author)

Ionizing radiation effects in Brazilian grape tree wine

International Nuclear Information System (INIS)

Harder, Marcia N.C.; Gutierrez, Érika M.R.; Arthur, Valter; Silva, Lúcia C.A.S.

2017-01-01

The aim of this work was to irradiate brazilian grape tree wines with gamma radiation (Co 60 ) to investigate the effect of radiation on its components and to create a new product for the superior quality fermented beverages market. For this wine was produced in an artisan way, but with all the care of hygiene and sanitation. The brazilian grape tree was fermented for five days and the wine was then filtered and stored in inert material containers then irradiated at 2.5 and 5 kGy doses. The samples were evaluated in relation to the radiation doses used. Physical and chemical analyzes of pH; total and volatile acidity; alcohol content; anthocyanins; tannins and colorimetry were performed. As a result, in most product analysis, had little effect on irradiation, except for anthocyanins and tannins. For this can be concluded that it is possible to develop a new fermented drink based on brazilian grape tree, according to the standards required by the legislation and that the irradiation at the dose of 5kGy was the sample that shown to have the most effect on the color because it was the one that degraded most molecules of anthocyanins and tannins. (author)

Influence of density on radiation-chemical yield of molecular hydrogen formed at radiolysis of aqueous solution of NaOH

International Nuclear Information System (INIS)

Jafarov, Y.D.; Hajiyeva, S.R.; Ramazanova, N.K.; Aliyev, S.M.; Alasgarov, A.M.

2014-01-01

Full text : In atom and nuclear energy the specialists knowledge about radiation-chemical yield of the initial products formed under the influence of ionizing rays on water is of great importance from the point of security. The radiation-chemical yields of molecular hydrogen have been defined according to the graph and the obtained results

The mechanism for the primary biological effects of ionizing radiation

International Nuclear Information System (INIS)

Byakov, Vsevolod M; Stepanov, Sergei V

2006-01-01

The primary biological response of living organisms to the passage of fast charged particles is traditionally believed to be dominated by the chemical reactions of the radical products from the radiolysis of cellular water (OH, H, e aq - , O 2 - , H 2 O 2 ) and by the bioradicals that they produce (and which can also result from the direct electronic activation of biomolecules). This understanding has provided insight into how ionizing radiations affect biological systems and, most importantly, what radioprotection and radiosensibilizing effects are produced by chemical compounds introduced into an organism. However, a number of key radiobiological facts remain unexplained by the current theory, stimulating a search for other biologically active factors that may be triggered by radiation. This review examines a fact that is usually ignored in discussing the biological impact of ionizing radiation: the local increase in acidity in the water solution along the track of a charged particle. The acidity in the track is very different from its value for cellular water in a living organism. Biological processes are well-known to be highly sensitive to changes in the environmental acidity. It seems that the biological impact of ionizing radiations is dominated not by the water radiolysis products (mostly radicals) listed above but particles of a different nature, hydroxonium ions H 3 O + , where the term hydroxonium refer to protonated water molecules. This modification of the mechanism of primary radiobiological effects is in good agreement with experimental data. In particular, the extremal dependence of the relative biological efficiency (RBE) of radiations on their ionizing energy losses is accounted for in quantitative terms, as is the increase in the RBE in the relativistic energy range. (reviews of topical problems)

Effects of the Mt. Pinatubo eruption on the chemistry, radiative, and transport processes in the stratosphere

International Nuclear Information System (INIS)

Wuebbles, D.J.; Kinnison, D.E.; Grant, K.E.; Connell, P.S.

1992-09-01

Volcanic eruptions can significantly impact trace gas distribution in the upper troposphere and lower stratosphere. Massive eruptions, produce large quantities of SO 2 , H 2 O, chlorine compounds, and particulates. Modeling the effects of these impulsive increases in traces gases and comparing the results with observations from ground and satellite measurements provide unique opportunities to test current multi-dimensional chemical-radiative-transport models of the global atmosphere. Since these models are currently being used in assessment studies for future anthropogenic emissions of trace gases quantitative understanding of the accuracy of these models is essential. In this study, we have used observed data from the Stratospheric Aerosol and Gas Experiment II (SAGE II) aboard the Earth Radiation Budget Satellite (ERBS) to realistically represent both the time dependent change in aerosol surface area density and wavelength dependent extinction values from the Mt. Pinatubo Eruption. Increases in the aerosol loading increase the rate of important heterogeneous chemical reactions converting odd nitrogen in both ClONO 2 and N 2 O 5 to HNO 3 . Radiative effects of increases aerosol optical thickness include changes to net radiative heating rates and to actinic fluxes. Changes to heating rates will indirectly change chemical reaction rates via changes in atmospheric temperatures. changes in actinic fluxes will directly modify photodissociation rates

RADIATION EFFECTS IN NUCLEAR WASTE MATERIALS

International Nuclear Information System (INIS)

Weber, William J.

2000-01-01

The objective of this research was to develop fundamental understanding and predictive models of radiation effects in glasses and ceramics at the atomic, microscopic, and macroscopic levels, as well as an understanding of the effects of these radiation-induced solid-state changes on dissolution kinetics (i.e., radionuclide release). The research performed during the duration of this project has addressed many of the scientific issues identified in the reports of two DOE panels [1,2], particularly those related to radiation effects on the structure of glasses and ceramics. The research approach taken by this project integrated experimental studies and computer simulations to develop comprehensive fundamental understanding and capabilities for predictive modeling of radiation effects and dissolution kinetics in both glasses and ceramics designed for the stabilization and immobilization of high-level tank waste (HLW), plutonium residues and scraps, surplus weapons plutonium, other actinides, and other highly radioactive waste streams. Such fundamental understanding is necessary in the development of predictive models because all experimental irradiation studies on nuclear waste materials are ''accelerated tests'' that add a great deal of uncertainty to predicted behavior because the damage rates are orders of magnitude higher than the actual damage rates expected in nuclear waste materials. Degradation and dissolution processes will change with damage rate and temperature. Only a fundamental understanding of the kinetics of all the physical and chemical processes induced or affected by radiation will lead to truly predictive models of long-term behavior and performance for nuclear waste materials. Predictive models of performance of nuclear waste materials must be scientifically based and address both radiation effects on structure (i.e., solid-state effects) and the effects of these solid-state structural changes on dissolution kinetics. The ultimate goal of this

Chemical structure and physical properties of radiation-induced crosslinking of polytetrafluoroethylene

International Nuclear Information System (INIS)

Oshima, Akihiro; Ikeda, Shigetoshi; Katoh, Etsuko; Tabata, Yoneho

2001-01-01

The chemical structure and physical properties of polytetrafluoroethylene (PTFE) that has been crosslinked by radiation have been studied by various methods. It has been found that a Y-type crosslinking structure and a Y-type structure incorporating a double bond (modified Y-type) is formed in PTFE by radiation-crosslinking in the molten state. In addition, various types of double bond structures, excluding the crosslinking site, have been identified. The crosslinked PTFE has a good light transparency due to the loss of crystallites, whilst it retains the excellent properties of electrical insulation and heat resistance. The coefficient of abrasion and the permanent creep are also greatly improved by crosslinking

Study the effect of gamma radiation pretreatment of sugarcane bagasse on its physcio-chemical morphological and structural properties

Science.gov (United States)

Kapoor, Khushboo; Garg, Neelima; Diwan, R. K.; Varshney, Lalit; Tyagi, Ajay K.

2017-12-01

Sugarcane bagasse was exposed to gamma radiation at different doses i.e. 100, 500, 1000 and 2000 kGy at a dose rate of 2.5 kGy/h and characterized for physical, chemical, morphological and structural properties. Results showed that on exposure of sugarcane bagasse, hemicellulose content reduced from 31% to 12.4% at 2000 kGy dose. The cellulose content of bagasse did not get affected much upto 1000 kGy exposure; however at 2000 kGy dose it decreased considerably. XRD study shows an initial increase in crystallinity index of bagasse at a dose level of 100 kGy while on further increase in radiation dose from 100 kGy to 2000 kGy the crystallinity index of bagasse decreases. Pores in the SEM photograph were observed on the surface of irradiated bagasse. UV-Vis spectra of bagasse showed a red shift indicating internal changes caused by radiation exposure. Study shows that the irradiation of bagasse results in disrupton of the lignocellulosic structure of Bagasse which opens up for easy accessibility of acids and hydrolytic enzymes for cellulosic hydrolysis resulting into fermentable sugars.

Detection and measurement of ionizing radiation

International Nuclear Information System (INIS)

Anon.

1990-01-01

All detection or measurement of radiation rests in the possibility of recognizing the interactions of radiation with matter. When radiation passes through any kind of material medium, all or a portion of its energy is transferred to this medium. This transferred energy produces an effect in the medium. In principle, the detection of radiation is based on the appearance and the observation of this effect. In theory, all of the effects produced by radiation may be used in detecting it: in practice, the effects most commonly employed are: (1) ionization of gases (gas detectors), or of some chemical substance which is transformed by radiation (photographic or chemical dosimeters); (2) excitations in scintillators or semiconductors (scintillation counters, semiconductor counters); (3) creation of structural defects through the passage of radiation (transparent thermoluminescent and radioluminescent detectors); and (4) raising of the temperature (calorimeters). This study evaluates in detail, instruments based on the ionization of gases and the production of luminescence. In addition, the authors summarize instruments which depend on other forms of interaction, used in radiation medicine and hygiene (radiology, nuclear medicine)

Biological effects of ionizing radiation

International Nuclear Information System (INIS)

Marko, A.M.

1981-05-01

In this review radiation produced by the nuclear industry is placed into context with other sources of radiation in our world. Human health effects of radiation, derivation of standards and risk estimates are reviewed in this document. The implications of exposing the worker and the general population to radiation generated by nuclear power are assessed. Effects of radiation are also reviewed. Finally, gaps in our knowledge concerning radiation are identified and current research on biological effects, on environmental aspects, and on dosimetry of radiation within AECL and Canada is documented in this report. (author)

Radiation protection in clinical chemical laboratories

International Nuclear Information System (INIS)

Jacob, K.

1980-01-01

In the clinical-chemical laboratory, the problems of the personal radiation protection can be handled relatively simply. Important conditions are certain requirements as far as the building is concerned and the keeping to protection measures to invoid ingestion, inhalation, and resorption of open radioactive substances. Very intensive attention must be paid to a clean working technique in order to be able to exclude the danger of contamination which is very disturbing during the extremely sensitive measurements. The higgest problem in the handling of open radioactive substances, however, is in our opinion the waste management because it requires which space and personnel this causing high costs. Furthermore, since 1 January 1979, the permission for the final storage of radioactive waste in the shut down mine ASSE was taken back from the county collection places and it cannot be said yet if and when this permission will be given again. (orig./HP) [de

Effects of radiation-counselling convergence education on radiation awareness

International Nuclear Information System (INIS)

Seoung, Youl Hun

2017-01-01

The purpose of study was to analysis on the effects of radiation-counselling convergence education on radiation awareness. The survey objects were students of radiation-counselling convergence education from 12th May to 22th June in 2016. The questionnaires were education satisfactions and radiation awareness (risk, benefit, control) by Likert-type 5 scales. The analysis results revealed that education satisfactions of men students showed a significant higher female students and correlation coefficient of education satisfactions were the best high in the benefit and control of radiation. Finally radiation-counselling convergence education had a significant effect on radiation benefit. This convergence education influenced positive recognition on radiation benefit and it was indicated that radiation-counselors could treat clients on the basis of radiation benefit

Effects of radiation-counselling convergence education on radiation awareness

Energy Technology Data Exchange (ETDEWEB)

Seoung, Youl Hun [Dept. of Radiological Science, College of Health Science, Cheongju University, Cheongju (Korea, Republic of)

2017-06-15

The purpose of study was to analysis on the effects of radiation-counselling convergence education on radiation awareness. The survey objects were students of radiation-counselling convergence education from 12th May to 22th June in 2016. The questionnaires were education satisfactions and radiation awareness (risk, benefit, control) by Likert-type 5 scales. The analysis results revealed that education satisfactions of men students showed a significant higher female students and correlation coefficient of education satisfactions were the best high in the benefit and control of radiation. Finally radiation-counselling convergence education had a significant effect on radiation benefit. This convergence education influenced positive recognition on radiation benefit and it was indicated that radiation-counselors could treat clients on the basis of radiation benefit.

Biological efficiency of interaction between various radiation and chemicals

International Nuclear Information System (INIS)

Kim, Jin Kyu; Yu, Dong Han; Lee, Byoung Hun; Petin, Vladislav G.; Geras'kin, Stanislav A.; Cebulska-Wasilewska, Antonina; Panek, Agnieszka; Wiechec, Anna

2004-06-01

This research project has been carried out jointly with INP (Poland) to develop technologies to assess the biological efficiency of interaction between radiation and chemicals. Through the cooperative project, KAERI and INP have established wide variety of bioassay techniques applicable to radiation bioscience, human monitoring, molecular epidemiology and environmental science. The joint experiment, in special, made it possible to utilize the merits of both institutes and to upgrade and verify KAERI's current technology level. All results of the cooperative research will be jointly published in high standard scientific journals listed in the Science Citation Index (SCI), which can make the role of fundamental basis for improving relationship between Korea and Poland. Research skills such as Trad-MCN assay, SCGE assay, immunohistochemical assay and molecular assay developed through joint research will be further elaborated and will be continuously used for the collaboration between two institutes

Genetic effects of combined chemical-X-ray treatments in male mouse germ cells

International Nuclear Information System (INIS)

Cattanach, B.M.; Rasberry, C.

1987-01-01

Several studies have shown that the yield of genetic damage induced by radiation in male mouse germ cells can be modified by chemical treatments. Pre-treatments with radio-protecting agents have given contradictory results but this appears to be largely attributable to the different germ cell stages tested and dependent upon the level of radiation damage induced. Pre-treatments which enhance the yield of genetic damage have been reported although, as yet, no tests have been conducted with radio-sensitizers. Another form of interaction between chemicals and radiation is specifically found with spermatogonial stem cells. Chemicals that kill cells can, by population depletion, substantially and predictably modify the genetic response to subsequent radiation exposure over a period of several days, or even weeks. Enhancement and reduction in the genetic yield can be attained, dependent upon the interval between treatments, with the modification also varying with the type of genetic damage scored. Post-treatment with one chemical (TEM) has been shown to reduce the genetic response to radiation exposure. (author)

Radiation and DNA

Energy Technology Data Exchange (ETDEWEB)

Riabchenko, N I

1979-01-01

Consideration is given to the effects of ionizing radiation on the structure of DNA. Physical and chemical methods of determining radiation damage to the primary (polynucleotide chain and nitrogenous base) and secondary (helical) structure of DNA are discussed, and the effects of ionizing radiation on deoxyribonucleoprotein complexes are considered. The radiolysis of DNA in vitro and in bacterial and mammalian cells is examined and cellular mechanisms for the repair of radiation-damaged DNA are considered, taking into account single-strand and double-strand breaks, gamma-radiation damage and deoxyribonucleoprotein-membrane complex damage. Postradiation DNA degradation in bacteria and lymphatic cells is also discussed.

Human genetic marker for resistance to radiations and chemicals. 1998 annual progress report

International Nuclear Information System (INIS)

Lieberman, H.B.

1998-01-01

'The broad objective of the project is to understand the molecular basis for the response of cells to radiations and chemicals, with the pragmatic goal of being able to identify human subpopulations that are exceptionally sensitive to DNA damaging agents. The project focuses on HRAD9, a human orthologue of the fission yeast Schizosaccharomyces pombe gene rad9. S. pombe rad9::ura4+ mutant cells are highly sensitive to ionizing radiation, UV and many chemicals, such as the DNA synthesis inhibitor hydroxyurea. They also lack the ability to delay cycling transiently in S phase or in G2 following a block in DNA replication or after incurring DNA damage, respectively -i.e., they lack checkpoint controls. The attempt by mutant cells to progress through mitosis in the absence of fully intact DNA accounts at least in part for their sensitivity to DNA damaging agents. Cells bearing rad9::ura4+ also aberrantly regulate UVDE, an enzyme that participates in a secondary DNA excision repair pathway. The key role played by S. pombe rad9 in promoting resistance to chemicals and radiations suggests that the evolutionarily conserved human cognate also has important functions in mammals. The first set of aims in this proposal centers on characterizing the structure and expression of HRAD9, to assess structure/function relationships and potentially link protein activity to a specific tissue. The next set of aims focuses on determining the role of HRAD9 in radio/chemoresponsiveness and cancer.'

The effect of the diazepam to the free radical under the brain radiation injury

International Nuclear Information System (INIS)

Huo Hongmei; Wang Chen; Zhang Zhilin

2007-01-01

Objective: To study the effect of the diazepam on free radical under in the brain radiation injury in the early stage. Methods: A model of whole brain radiation injury in wakefulness was established in the Sprague-Dawley rat. Diazepam was given intraperitoneally 30 minutes before radiation. The brain tissue homogenate was prepared respectively while the rats were executed 6 hours, 1 day, 1 week, 1 month after irradiation. The contents of the superoxide dismutase (SOD) and the malondialdehyde (MDA) in the tissue homogenate were measured by chemical colorimetry. Results: Diazepam could increase the vigor of SOD and reduce the MDA contents after irradiated. Conclusions: Diazepam has certain neuroprotection effect on radiation injury and decreasing the level of the free radicals. (authors)

Studies on chemical protectors against radiation, 31

International Nuclear Information System (INIS)

Sato, Yushi; Ohta, Setsuko; Shinoda, Masato

1990-01-01

Protective effects of Aloe arborescens (AA) on mouse skin injury induced by soft X-irradiation were examined. The mechanisms on radiation protection by measuring scavenge activity of activated oxygen, protective effects of nucleic acid, induction of antioxidative protein and so on were further investigated. Consequently a significant protective effect of skin injury was observed in AA S6-3-b. As the mechanisms of radiation protection in AA, the following matters were found. AA S6-3-b showed scavenge activity of hydroxyl radicals generated by Haber-Weiss reaction. AA S6-3-b suppressed the changes of activity in superoxide dismutase and gluthathione peroxidase at 7d after soft X-irradiation. Metallothionein was induced in the skin and liver against normal mice at 24 h after administration of AA S6-3-b. (author)

Radiation-induced effects in organic systems. Final report

International Nuclear Information System (INIS)

Johnsen, R.H.

1982-01-01

This project, which is of twenty-seven years duration, has been devoted to furthering our basic understanding of the processes involved in the absorption and distribution of high-energy radiation in organic molecules. The early phases of the work were concerned with the gross chemical effects of radiation and included studies in a number of important classes of organic compounds including alcohols, aliphatic acids, aliphatic hydrocarbons, and aromatic hydrocarbons. Basic information was acquired through these studies that has led to a better understanding of the effects of high-energy radiation on condensed media. During this period the so-called protective effect of low concentrations of aromatic hydrocarbons was also studied. A contribution of lasting significance at this time was the development of a technique for the post-radiolysis analysis of trapped free radicals by photochemical means. A comprehensive series of papers on the reactions of thermal hydrogen atoms with frozen organic substrates represented the beginning of a new phase in the approach to the problems of radiation chemistry in this laboratory. Since that time the general philosophy guided the research has been to single out events or processes suspected of contributing to the gross-radiation effect and study them in isolation. Thus from 1970 on efforts were devoted to charge-exchange processes, ionization efficiencies (w-values), radical decay process in solids and ion-dissociation reactions. The first by means of a modified time-of-flight mass spectrometer, the second utilizing an ionization chamber constructed in the FSU shops, the third using electron spin resonance detection, and the last involving the use of a dual mass spectrometer, solid target system invented in our laboratory. The most productive of these efforts has been the radical decay work

Effect of solar radiation on the functional components of mulberry (Morus alba L.) leaves.

Science.gov (United States)

Sugiyama, Mari; Katsube, Takuya; Koyama, Akio; Itamura, Hiroyuki

2016-08-01

The functional components of mulberry leaves have attracted the attention of the health food industry, and increasing their concentrations is an industry goal. This study investigated the effects of solar radiation, which may influence the production of flavonol and 1-deoxynojirimycin (DNJ) functional components in mulberry leaves, by comparing a greenhouse (poor solar radiation) and outdoor (rich solar radiation) setting. The level of flavonol in leaves cultivated in the greenhouse was markedly decreased when compared with those cultivated outdoors. In contrast, the DNJ content in greenhouse-cultivated plants was increased only slightly when compared with those cultivated outdoors. Interestingly, the flavonol content was markedly increased in the upper leaves of mulberry trees that were transferred from a greenhouse to the outdoors compared with those cultivated only in the outdoors. Solar radiation conditions influence the synthesis of flavonol and DNJ, the functional components of mulberry leaves. Under high solar radiation, the flavonol level becomes very high but the DNJ level becomes slightly lower, suggesting that the impact of solar radiation is great on flavonol but small on DNJ synthesis. © 2016 Society of Chemical Industry. © 2016 Society of Chemical Industry.

Biological effects of concomitant influence of radioactive and chemical factors. (Experimental research)

International Nuclear Information System (INIS)

Meshkov, N.A.

1995-01-01

Remote consequences of concomitant influence of radioactive and chemical hazards substances, modeling the ecological situation at the territory of the Altaj region after the nuclear tests at the Semipalatinsk test site is studied on the mice. Negative effect of the concomitant impact of radioactive and hazardous chemical substances on the basic morpho-functional systems of animals is revealed; the reproduction function proved to be the most sensitive one. It is noted that the radiation factor constitutes the basis of all violations of bone marrow blood-producing function by concomitant influence

Chemical systems in aqueous solutions for using in the holographic ionizing radiation

International Nuclear Information System (INIS)

Nicolau-Rebigan, S.

1979-01-01

Some types of chemical systems in aqueous solutions for utilization as active media in holographic ionizing radiation dosimeter are presented. One discussed some advantages of the holographic dosimeter comparatively with another existing types. It is outlined the advantages of using aqueousss solutions as active media in holographic dosimeter. (author)

Chemical stress relaxation of ethylene-propylene copolymer rubber by heat and radiation

International Nuclear Information System (INIS)

Ito, M.; Okada, S.; Kuriyama, I.

1980-01-01

An attempt was made to shorten the evaluation time for the deterioration under various conditions caused by chemical reactions by extending the time-temperature superposition principle for the stress relaxation of rubber. In the case of deterioration by radiation instead of by heat, a time-dose rate reduction is proposed and the master curves obtained for chemical-stress relaxation of rubber. A new method which contains a numerical analysis of stress decay curves is proposed to obtain the rate of crosslinking and scission under irradiation for already crosslinked samples. (author)

[Pulse-modulated Electromagnetic Radiation of Extremely High Frequencies Protects Cellular DNA against Damaging Effect of Physico-Chemical Factors in vitro].

Science.gov (United States)

Gapeyev, A B; Lukyanova, N A

2015-01-01

Using a comet assay technique, we investigated protective effects of. extremely high frequency electromagnetic radiation in combination with the damaging effect of X-ray irradiation, the effect of damaging agents hydrogen peroxide and methyl methanesulfonate on DNA in mouse whole blood leukocytes. It was shown that the preliminary exposure of the cells to low intensity pulse-modulated electromagnetic radiation (42.2 GHz, 0.1 mW/cm2, 20-min exposure, modulation frequencies of 1 and 16 Hz) caused protective effects decreasing the DNA damage by 20-45%. The efficacy of pulse-modulated electromagnetic radiation depended on the type of genotoxic agent and increased in a row methyl methanesulfonate--X-rays--hydrogen peroxide. Continuous electromagnetic radiation was ineffective. The mechanisms of protective effects may be connected with an induction of the adaptive response by nanomolar concentrations of reactive oxygen species formed by pulse-modulated electromagnetic radiation.

Effects of combined exposure of F344 rats to inhaled Plutonium-239 dioxide and a chemical carcinogen (NNK)

Energy Technology Data Exchange (ETDEWEB)

Lundgren, D.L.; Carlton, W.W. [Purdue Univ., Lafayette, IN (United States); Griffith, W.C. [and others

1995-12-01

Workers in nuclear weapons facilities have a significant potential for exposure to chemical carcinogens and to radiation from external sources or from internally deposited radionuclides such as {sup 239}Pu. Although the carcinogenic effects of inhaled {sup 239}Pu and many chemicals have been studied individually, very little information is available on their combined effects. One chemical carcinogen that workers could be exposed to via tobacco smoke is the tobacco-specific nitrosamine 4-(N-methyl-n-nitrosamino)-1-(3-pyridyl)-1(3-pyridyl)-1-butanone (NNK), a product of tobacco curing and the pyrolysis of nicotine in tobacco. NNK causes lung tumors in rats, regardless of the route of administration and to a lesser extent liver, nasal, and pancreatic tumors. From the results presented, it can be concluded that exposure to a chemical carcinogen (NNK) in combination with {alpha}-particle radiation from inhaled {sup 239}PuO{sub 2} acts in, at best, an additive manner in inducing lung cancer in rats.

Gamma-radiation effect on the parameters of the population recovery of plants

Directory of Open Access Journals (Sweden)

N.I. Ivanishvili

2016-12-01

Full Text Available Investigation of the effects of different physic-chemical factors on the ecosystems is one of the important scientific tasks. From this perspective, it is to be mentioned an effect of such a strong damaging factor as ionizing radiation. Radiation damage is reflected differently in relation to the levels of organization of living organisms. On the relatively early stage of radiation damage determination of post-irradiation regeneration indicators on population level gives possibility to forecast the sustainability of ecosystems. In order to determine the indicators of post-irradiation regeneration of plant populations we have used as a model water plant – Lemna minor L. During the exposure of radiation on different levels of organization differences are identified not only according to qualitative features but also by the character of direction of the development of the processes of postradiation regeneration. A conclusion is made that if during the acute radiation it is possible to determine radioresistance of certain plants, which is based on the plant potential to post-radiation regeneration, the investigation carried out through chronic irradiation gives the possibility to determine the indicators of the ability of the plant to adapt to the radiation.

Biological radiation effects

International Nuclear Information System (INIS)

Kiefer, J.

1989-01-01

The book covers all aspects of biological radiation effects. The physical basis is dealt with in some detail, and the effects at the subcellular and the cellular level are discussed, taking into account modern developments and techniques. The effects on the human organism are reviewed, both from the point of view of applications in medicine as well as with regard to radiation hazards (teratogenic, gonadal and carcinogenic effects)

First picosecond in radiation chemistry

International Nuclear Information System (INIS)

Bednar, J.

1983-01-01

The early processes of absorption by matter of ionizing radiation are discussed on the level of collision processes of electrons of the degradation spectrum of radiation with molecules of the medium. A short survey of the processes of initial excitations, superexcitations and ionizations is given occurring during absorption and relaxation processes. Collisions of fast charged particles with atoms and molecules are discussed within the first Bethe-Born approximation. A short theoretical description is given of the basic radiation chemical quantities, such as primary radiation chemical yield g and total absorbed energy Q/sub tot/ due to energy absorption from the totality of fast and slow electrons of the degradation spectrum. A short survey of current chemical and physical models of the track of a fast electron in condensed media is given together with some comments on the effect of the chemical composition of the medium on its initial radiation chemical decomposition. The model of the molecule in a high Rydberg state is sketched briefly together with some implications for radiation chemistry of formation and decay of this kind of highly excited matter. In conclusion, a survey of the initial yields of products in gases and track entities in liquids is presented and a few remarks are made concerning the intrinsic problems of radiation sciences, i.e. radiation physics, chemistry, dosimetry and biology

Toxic effects of ultraviolet radiation on the skin

International Nuclear Information System (INIS)

Matsumura, Yasuhiro; Ananthaswamy, Honnavara N.

2004-01-01

Ultraviolet (UV) irradiation present in sunlight is an environmental human carcinogen. The toxic effects of UV from natural sunlight and therapeutic artificial lamps are a major concern for human health. The major acute effects of UV irradiation on normal human skin comprise sunburn inflammation (erythema), tanning, and local or systemic immunosuppression. At the molecular level, UV irradiation causes DNA damage such as cyclobutane pyrimidine dimers and (6-4) photoproducts, which are usually repaired by nucleotide excision repair (NER). Chronic exposure to UV irradiation leads to photoaging, immunosuppression, and ultimately photocarcinogenesis. Photocarcinogenesis involves the accumulation of genetic changes, as well as immune system modulation, and ultimately leads to the development of skin cancers. In the clinic, artificial lamps emitting UVB (280-320 nm) and UVA (320-400 nm) radiation in combination with chemical drugs are used in the therapy of many skin diseases including psoriasis and vitiligo. Although such therapy is beneficial, it is accompanied with undesirable side effects. Thus, UV radiation is like two sides of the same coin--on one side, it has detrimental effects, and on the other side, it has beneficial effects

Establishing exposure limits for chemical pollutants

International Nuclear Information System (INIS)

Drosselmeyer, E.

1979-05-01

In addition to toxic effects, chemical pollutants may produce cancer and genetic damage as radiation does. Some of these effects have been known since a very long time. Inspite of this fact, the knowledge of the basic processes in damage formation, of dose-effect relationships, and of possible threshold values seem to be at least comparable in the field of radiation protection. The attempt is made to give an introduction into the problems by a literature survey of the effects on man of heavy metals, especially of lead. Subsequently the exposure limits for different groups of the population and the legal national and international standards are considered. Efforts to quantify the relationship existing between different pollutants by the definition of a 'radiation equivalent' dose for chemicals deserve particular interest. (orig.) [de

Immunobiological, biochemical, and physico-chemical characteristics of Brucella lipopolysaccharide subjected to various doses of gamma radiation

Energy Technology Data Exchange (ETDEWEB)

Dranovskaya, E A; Shibaeva, I V [Akademiya Meditsinskikh Nauk SSSR, Moscow. Inst. Ehpidemiologii i Mikrobiologii; Khabakpasheva, N A; Rostovtseva, N A [Institut Vaktsin i Syvorotok, Moscow (USSR)

1975-01-01

A comparative study is presented of toxicity, serological activity, some biochemical and physico-chemical properties of the highly toxic Brucella lipopolysaccharide (LPS) and of preparations obtained as a result of gamma irradiation in doses of 1, 3, and 10 mrad on the antigen. The toxicity of LPS was found to decrease with increasing radiation dose. Irradiation with a dose of 3 mrad produced a marked decrease in the toxicity of the antigen without essentially changing its serological properties. The process of LPS detoxication under the effect of irradiation was accompanied by changes in certain biochemical and physico-chemical indices suggestive of a modification of the primary structure of the LPS molecule and of an impairment especially of its polysaccharide side chains.

Immunobiological, biochemical and physico-chemical characteristics of Brucella lipopolysaccharide subjected to various doses of gamma radiation

International Nuclear Information System (INIS)

Dranovskaya, E.A.; Shibaeva, I.V.

1975-01-01

A comparative study is presented of toxicity, serological activity, some biochemical and physico-chemical properties of the highly toxic Brucella lipopolysaccharide (LPS) and of preparations obtained as a result of gamma irradiation in doses of 1, 3, and 10 mrad on the antigen. The toxicity of LPS was found to decrease with increasing radiation dose. Irradiation with a dose of 3 mrad produced a marked decrease in the toxicity of the antigen without essentially changing its serological properties. The process of LPS detoxication under the effect of irradiation was accompanied by changes in certain biochemical and physico-chemical indices suggestive of a modification of the primary structure of the LPS molecule and of an impairment especially of its polysaccharide side chains. (author)

Biological effects of particle radiation

International Nuclear Information System (INIS)

Sakamoto, Kiyohiko

1988-01-01

Conventional radiations such as photons, gamma rays or electrons show several physical or biological disadvantages to bring tumors to cure, therefore, more and more attentions is being paid to new modalitie such as fast neutrons, protons, negative pions and heavy ions, which are expected to overcome some of the defects of the conventional radiations. Except for fast neutrons, these particle radiations show excellet physical dose localization in tissue, moreover, in terms of biological effects, they demonstrate several features compared to conventional radiations, namely low oxygen enhancement ratio, high value of relative biological effectiveness, smaller cellular recovery, larger therapeutic gain factor and less cell cycle dependency in radiation sensitivity. In present paper the biological effects of particle radiations are shown comparing to the effects of conventional radiations. (author)

Near-field photochemical and radiation-induced chemical fabrication of nanopatterns of a self-assembled silane monolayer

Directory of Open Access Journals (Sweden)

Ulrich C. Fischer

2014-09-01

Full Text Available A general concept for parallel near-field photochemical and radiation-induced chemical processes for the fabrication of nanopatterns of a self-assembled monolayer (SAM of (3-aminopropyltriethoxysilane (APTES is explored with three different processes: 1 a near-field photochemical process by photochemical bleaching of a monomolecular layer of dye molecules chemically bound to an APTES SAM, 2 a chemical process induced by oxygen plasma etching as well as 3 a combined near-field UV-photochemical and ozone-induced chemical process, which is applied directly to an APTES SAM. All approaches employ a sandwich configuration of the surface-supported SAM, and a lithographic mask in form of gold nanostructures fabricated through colloidal sphere lithography (CL, which is either exposed to visible light, oxygen plasma or an UV–ozone atmosphere. The gold mask has the function to inhibit the photochemical reactions by highly localized near-field interactions between metal mask and SAM and to inhibit the radiation-induced chemical reactions by casting a highly localized shadow. The removal of the gold mask reveals the SAM nanopattern.

Radioprotective effect of sulphydryl group containing triazole derivative to modulate the radiation-induced clastogenic effects

International Nuclear Information System (INIS)

Suchetha Kumari, N.; Madhu, L.N.

2012-01-01

Protection of biological systems against radiation damage is of paramount importance during accidental and unavoidable exposure to radiation. Several physico-chemical and biological factors collectively contribute to the damage caused by radiation and are, therefore, targets for developing radioprotectors. Chemicals capable of scavenging free radicals, relieving oxidative stress, promoting antioxidant activity and modulating immune response have been some of the radioprotectors extensively investigated with limited success. It has long been known that some of the most effective radioprotective agents are those which contain sulphydryl groups. The present study reports an evaluation of radical scavenging property and radioprotective property of sulphydryl group containing triazole derivative. The lethal dose of Electron beam radiation (EBR) was studied by survival assay. The dose reduction factor (DRF) of 4-amino-5-mercapto-3-methyl-1,2,4-triazole (TR1) was calculated by taking the ratio between LD 50 of EBR with and without TR1 treatment. Radical scavenging property of TR1 was assessed by DPPH radical scavenging assay. The clastogenic effects of EBR were recorded by Micronucleus test in bone marrow cells and DNA fragmentation assay in hepatic cells of mice. The survival assay results showed that 10Gy was the LD 50 of EBR. The calculated DRF for TR1 was found to be 1.2. DPPH radical scavenging assay showed a positive result when it compared with the standard glutathione. Treatment of mice with 100 mg of TR1 for 15 days before irradiation significantly (P<0.05) reduced the frequency of micronucleus formation in bone marrow cells and also reduced the DNA fragmentation in hepatic cells. The result obtained in the present study concludes that TR1 has a protective effect against the EBR-induced mortality and clastogenicity. (author)

Evaluation of ionizing radiation effects in bone tissue by FTIR spectroscopy and dynamic mechanical analysis

International Nuclear Information System (INIS)

Veloso, Marcelo N.; Santin, Stefany P.; Benetti, Carolina; Pereira, Thiago M.; Mattor, Monica B.; Politano, Rodolfo; Zezell, Denise M.

2013-01-01

In many medical practices the bone tissue exposure to ionizing radiation is necessary. However, this radiation can interact with bone tissue in a molecular level, causing chemical and mechanical changes related with the dose used. The aim of this study was verify the changes promoted by different doses of ionizing radiation in bone tissue using spectroscopy technique of Attenuate Total Reflectance - Fourier Transforms Infrared (ATR-FTIR) and dynamic mechanical analysis. Samples of bovine bone were irradiated using irradiator of Cobalt-60 with five different doses between 0.01 kGy, 0.1 kGy,1 kGy, 15 kGy and 75 kGy. To study the effects of ionizing irradiation on bone chemical structure the sub-bands of amide I and the crystallinity index were studied. The mechanical changes were evaluated using the elastic modulus and the damping value. To verify if the chemical changes and the bone mechanic characteristics were related, it was made one study about the correlation between the crystallinity index and the elastic modulus, between the sub-bands ratio and the damping value and between the sub-bands ratio and the elastic modulus. It was possible to evaluate the effects of different dose of ionizing radiation in bone tissue. With ATR-FTIR spectroscopy analysis, it was possible observe changes in the organic components and in the hydroxyapatite crystals organization. Changes were also observed in the mechanical properties. A good correlation between the techniques was found, however, it was not possible to establish a linear or exponential dependence between dose and effect. (author)

The effective use of physical and chemical mutagen in the induction of mutation for crop improvement in Malaysia

International Nuclear Information System (INIS)

Abdul Rahim Harun

2001-01-01

The earliest work of induced mutations breeding program in Malaysia was reported in 1967. The project was carried out by Rubber Research Institute of Malaysia using x-radiation in an attempt to improve rubber trees for dwarfism and disease resistance. Subsequently, more efforts were taken up by the universities to promote the technology for genetic changes and creation of new genetic resources, particularly in crops that are not easily achievable through conventional techniques. Gamma radiation is always been used as physical mutagen, while ethyl methane sulfonate (EMS) was a popular chemical mutagen used in induced mutation breeding in the country. Gamma rays is an effective mutagen to which more than 30 potential mutants were produced up to now through mutagenesis of several important food crops and ornamental plants. Although chemical mutagen such as EMS were reported being used, the result is not so convincing as compared to gamma radiation. Malaysian Institute for Nuclear Technology Research (MINT) has initiated and promoted nuclear technique in mutation breeding for the improvement of importance food crops such as rice, legume and other potential crops for export, like fruit trees and ornamentals. Gamma radiation is the main source of mutagen used in mutation-breeding programme at MINT. The effectiveness of these two mutagens were verified with mutants derived through induced mutation breeding in the country which some mutant has shown outstanding improvement and released as new varieties and cultivars. This paper summarises and discuss the effects as well as achievement attained through the use of ionizing radiation and chemical mutagen in plant mutation breeding in Malaysia. (author)

The effective use of physical and chemical mutagen in the induction of mutation for crop improvement in Malaysia

Energy Technology Data Exchange (ETDEWEB)

Abdul Rahim Harun [Malaysian Institute for Nuclear Technology Research, Bangi, Selangor (Malaysia)

2001-03-01

The earliest work of induced mutations breeding program in Malaysia was reported in 1967. The project was carried out by Rubber Research Institute of Malaysia using x-radiation in an attempt to improve rubber trees for dwarfism and disease resistance. Subsequently, more efforts were taken up by the universities to promote the technology for genetic changes and creation of new genetic resources, particularly in crops that are not easily achievable through conventional techniques. Gamma radiation is always been used as physical mutagen, while ethyl methane sulfonate (EMS) was a popular chemical mutagen used in induced mutation breeding in the country. Gamma rays is an effective mutagen to which more than 30 potential mutants were produced up to now through mutagenesis of several important food crops and ornamental plants. Although chemical mutagen such as EMS were reported being used, the result is not so convincing as compared to gamma radiation. Malaysian Institute for Nuclear Technology Research (MINT) has initiated and promoted nuclear technique in mutation breeding for the improvement of importance food crops such as rice, legume and other potential crops for export, like fruit trees and ornamentals. Gamma radiation is the main source of mutagen used in mutation-breeding programme at MINT. The effectiveness of these two mutagens were verified with mutants derived through induced mutation breeding in the country which some mutant has shown outstanding improvement and released as new varieties and cultivars. This paper summarises and discuss the effects as well as achievement attained through the use of ionizing radiation and chemical mutagen in plant mutation breeding in Malaysia. (author)

Biological effects of ionising radiation

International Nuclear Information System (INIS)

Anon.

1987-01-01

The paper reports the proceedings of a conference organised jointly by Friends of the Earth (U.K.) and Greenpeace (International). The aim of the conference was to discuss the effects of low level radiation, particularly on man, within the terms of dose/risk relationships. The topics discussed included: sources of radiation, radiation discharges from nuclear establishments, predictive modelling of radiation hazards, radiation effects at Hiroshima, low dose effects and ICRP dose limits, variation in sensitivity to radiation, and the link between childhood cancer and nuclear power. (U.K.)