Half-life measurements at the National Institute of Standards and Technology

Unterweger, Michael P.

doi:10.1016/s0969-8043(01)00177-4

Cited by 116 publications

(24 citation statements)

References 4 publications

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“…The 134 Cs emission inventory should be almost the same as that of 137 Cs, i.e., 1.2 × 10 16 Bq (12 PBq; Steinhauser et al 2014) because the activity ratio of these two isotopes was almost united in the case of the FDNPP accident (e.g., Merz et al 2013). There have been concerns that the deposited radiocesium will influence the contaminated area for an extended period, in contrast to the effects of radioiodine, because the half-lives of 134 Cs and 137 Cs are relatively long: 2.06 years and 30.17 years, respectively (Dietz and Pachucki 1973;Unterweger 2002). Figure 1 shows the contaminated deposition density map for 134,137 Cs (the unit of deposition density is Bq m − 2 ) measured from October to November 2011 by the Ministry of Education, Culture, Sports, Science and Technology, Japan (MEXT) (2011).…”

Section: Introductionmentioning

confidence: 99%

The seasonal variations of atmospheric 134,137Cs activity and possible host particles for their resuspension in the contaminated areas of Tsushima and Yamakiya, Fukushima, Japan

Kinase

Kita

Igarashi

et al. 2018

Prog Earth Planet Sci

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A large quantity of radionuclides was released by the Fukushima Daiichi Nuclear Power Plant accident in March 2011, and those deposited on ground and vegetation could return to the atmosphere through resuspension processes. Although the resuspension has been proposed to occur with wind blow, biomass burning, ecosystem activities, etc., the dominant process in contaminated areas of Fukushima is not fully understood. We have examined the resuspension process of radiocesium ( 134,137 Cs) based on long-term measurements of the atmospheric concentration of radiocesium activity (the radiocesium concentration) at four sites in the contaminated areas of Fukushima as well as the aerosol characteristic observations by scanning electron microscopy (SEM) and the measurement of the biomass burning tracer, levoglucosan. The radiocesium concentrations at all sites showed a similar seasonal variation: low from winter to early spring and high from late spring to early autumn. In late spring, they showed positive peaks that coincided with the wind speed peaks. However, in summer and autumn, they were correlated positively with atmospheric temperature but negatively with wind speed. These results differed from previous studies based on data at urban sites. The difference of radiocesium concentrations at two sites, which are located within a 1 km range but have different degrees of surface contamination, was large from winter to late spring and small in summer and autumn, indicating that resuspension occurs locally and/or that atmospheric radiocesium was not well mixed in winter/spring, and it was opposite in summer/autumn. These results suggest that the resuspension processes and the host particles of the radiocesium resuspension changed seasonally. The SEM analyses showed that the dominant coarse particles in summer and autumn were organic ones, such as pollen, spores, and microorganisms. Biological activities in forest ecosystems can contribute considerably to the radiocesium resuspension in these seasons. During winter and spring, soil, mineral, and vegetation debris were predominant coarse particles in the atmosphere, and the radiocesium resuspension in these seasons can be attributed to the wind blow of these particles. Any proofs that biomass (Continued on next page)

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Section: Introductionmentioning

confidence: 99%

The seasonal variations of atmospheric 134,137Cs activity and possible host particles for their resuspension in the contaminated areas of Tsushima and Yamakiya, Fukushima, Japan

Kinase

Kita

Igarashi

et al. 2018

Prog Earth Planet Sci

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“…Crystallographic studies showed that the coordination sphere consisted of the Ga 3+ centre, three N atoms (from the macrocycle) and three O atoms (two from the pendant COOH groups and one from the amide group), forming a distorted octahedral geometry. HSF values after 1 h incubation with CHO and CT-26 cell lines were 1.8 and 1.5, respectively for 78, and 5.6 and 2.6, respectively, for 79, comparable to those of Ga nitroimidazole complexes (77)(78)(79).…”

Section: The Ligand Of Choice For 67mentioning

confidence: 59%

Bifunctional Metal – Nitroimidazole Complexes for Hypoxia Theranosis in Cancer

Ricardo¹,

Kumar²,

Wiebe³

2015

J Diagn Imaging Ther

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Oxygen supply -demand imbalances can render proliferating cells acutely or chronically hypoxic. In cancer cells, hypoxia-induced pathophysiological changes give rise to genetic changes that lead to treatment-resistant, aggressive phenotypes. The reduced curability of hypoxic tumours by radiotherapy is one of consequent challenges, but their hypoxia also offers unique, exploitable properties. Nitroimidazoles, for example, capitalize on oxygen-sensitive reductive activation to achieve hypoxiaselective localization for theranostic consequence. The discovery of 2-nitroimidazole (azomycin) heralded the development of many drugs, including effective radiosensitizers of hypoxic cells. These electron-affinic, reductively bioactivated nitroheterocyclics undergo initial oxygen-reversible, enzymatic one-electron reductions that lead to the formation of molecular adducts that impair vital

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“…Telecobalt machines are prominently used for cancer treatment; cobalt-60 is a synthetic radioactive isotope of cobalt with a half-life of 5.27 years. The use of cobalt-60 in irradiation demands the calculus of absorbed dose constant; allowing the calculation of the equivalent dose, which depends on distance and source activity [3] . The biological reactions to ionizing radiation appear as a natural response of the body to a physical agent causing a chemical effect resulting in a biological effect.…”

Section: Introductionmentioning

confidence: 99%

Feed variation and biometrical factors in tilapias (Oreochromis niloticus) exposed to 60Co gamma radiation

Giarola

Borin

Hormaza

et al. 2016

AIP Conference Proceedings

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Abstract. Ionizing radiation has been widely used for cancer treatment and diagnostic exams in medicine, besides being used in the fields of energy generation and industry. This work aimed to verify the occurrence of biological effects of high doses of gamma radiation using biometric tests in Nile tilapia. 32 fishes where divided into four groups: a control group and three groups irradiated with different values of absorbed dose (20 Gy, 40 Gy and 80 Gy). The fish showed high resistance to the deleterious effects of gamma radiation. Future studies may prove the use of fish for monitoring radiation contaminated environments.

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Half-life measurements at the National Institute of Standards and Technology

Cited by 116 publications

References 4 publications

The seasonal variations of atmospheric 134,137Cs activity and possible host particles for their resuspension in the contaminated areas of Tsushima and Yamakiya, Fukushima, Japan

The seasonal variations of atmospheric 134,137Cs activity and possible host particles for their resuspension in the contaminated areas of Tsushima and Yamakiya, Fukushima, Japan

Bifunctional Metal – Nitroimidazole Complexes for Hypoxia Theranosis in Cancer

Feed variation and biometrical factors in tilapias (Oreochromis niloticus) exposed to 60Co gamma radiation

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