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Abstract  

Gamma-ray irradiations for various spin crossover iron/III/ complexes were performed in order to examine the spin transition mechanism. The difference of the spin transition mechanisms was reflected in the differences of the fractions that the electronic state of iron atoms changed to low-spin at low temperature and the results were explained by using a phenomenological model.

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Abstract  

Ash contents of some coal samples from Enugu mines in Nigeria were measured using gamma-ray irradiation technique. The method employed gamma-ray energies of 0.060, 0.662 and 1.33 MeV of241Am,137Cs and60Co, respectively, and a counting system with a scintillation detector, to obtain empirical relationships between the conventionally determined ash content and the measured gamma-attenuation coefficient in the sample. The sensitivity of the method was observed to decrease drastically with increase in ash content above 35% ash, and with increase in energy of the gamma-ray. Further analyses showed that the error in the ash content determination was due to iron content which was not constant, but increased with ash content, with vidth variation above a mean value of ±0.64% Fe2O3.

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biological activities. T. pallescens is one of the most widespread and probably the most abundant Algerian Thymus species. The main goal of the herein reported study is to institute the influence of gamma ray irradiation of dried leaves of T. pallescens

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Abstract  

A technique has been proposed to promote hydrogen production from water by increasing the energy deposition in water through the conversion of γ-ray to low-energy electrons, which is achieved by putting solid materials into water. Simulation studies by the MCNP code indicate that the average deposited energy in water can be increased by optimizing geometry of the materials. In the present experiments using Al2O3 particles of various average diameters, the maximum amount of hydrogen produced is 3.48 μmol/cm3 for the water containing Al2O3 particles of 3 μm diameter, which is more than two order of magnitude larger of the H2 produced in water-only configuration.

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Journal of Radioanalytical and Nuclear Chemistry
Authors: J. Baptista, D. Vieira, A. Galisteo-Júnior, P. Caproni, M. Casare, H. de Andrade-Júnior, P. Spencer, and N. Nascimento

Abstract  

We investigated the immunological behavior of BTHX-1, before and after irradiation. SDS-PAGE showed that BTHX-1 irradiated in the presence of NaNO3, had its structure preserved. Animals’ plasma immunized with native BTHX-1 had high IgG1 titers. The irradiated protein induced high titers of IgG2b. When the toxin was irradiated with t-butanol, there was a slight decrease in the production of IgG2b. Real-time PCR showed that both the IL-2 as for IL4 was more expression from the cells of the animals immunized with BTHX-1 irradiated. These results indicate that irradiation of proteins leads to significant structural modifications.

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Abstract  

Ionizing radiation is shown not to create any additional lattice defects in yttriumaluminium garnet (YAG) due to their high radiation stability. However, it generates different kinds of electron-hole centres that are stabilized on structural imperfections. In the temperature range 77–300 K three kinds of trapping centres in YAG irradiated by γ-rays have been identified by means of ESR and thermoluminescence technique, namely an electron centre of the first type with g=1.996, stable within the temperature range 77–150 K, a hole centre of the second type (g=2.018) existing up to 250 K and a hole centre of the third type (g=2.016) stable at 300 K. Localisation of these centres in the garnet lattice is discussed and their participation in the luminescence processes considered. The influence of the crystallochemical nature of doped ions (Nd, Ce, Cr) on the stabilization of each of these electron-hole centres has also been studied.

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Abstract  

The degradation and mineralization of dibutyl phthalate (DBP), one of endocrine disruptors, by g-ray irradiation were demonstrated. The degradation was enhanced by the effective energy conversion of g-rays to low-energy electrons and photons with the assistance of the interactions between g-rays and metals, which is especially in the case of high Z materials effective. Numerical simulations using EGS code supported the experimental results. Improvements of the energy conversion process are also suggested by controlling the shape of the metal and its spatial configuration in the DBP solution.

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Abstract  

The equilibirum sorption capacity of hydrous ferric oxide and ferric phosphate has been observed to increase on irradiation with γ-rays by 5.2 and 6.6%, respectively. The rate of sorption increases differently in the irradiated exchanger materials depending upon their characteristics nature; e.g., when the concentration of the Zn(ammine) solution is 0.10M, increase in the F-values, caused by irradiation is significantly more striking in the case of hydrous ferric oxide than in ferric phosphate. On the other hand, at lower external concentration of the Zn(ammine) ion (0.01M), the increase in F-values is more significant in the case of ferric phosphate.

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Abstract  

The behavior of the triterpenes friedelin and friedelan-3-ol, contained on the leaves ofMaytenus aquifolium Martius (Celastraceae), upon several doses of X- and -rays (10 to 100 kGy), was investigated by high resolution gas chromatography (HRGC) and high resolution, gas chromatography —mass spectrometry (HRGC-MS). The friedelin content has not changed with -irradiation, but the content of friedelan-3-ol decreased around 17% at doses of 10, 20 and 40 kGy and around 27% at doses of 60, 80 and 100 kGy. The levels of both triterpenes remained unchanged even, at higher X-ray doses. Lupen-3-one was detected by HRGC-MS.

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Journal of Radioanalytical and Nuclear Chemistry
Authors: J. Baptista, D. Vieira, A. Galisteo Júnior, O. Higa, M. Casare, C. Yonamine, P. Caproni, L. Campos, H. de Andrade Júnior, P. Spencer, and N. Nascimento

Abstract  

In this work, the authors investigated the immunological behavior of bothropstoxin-I (BTHX-1), before and after irradiation process, and also the influence of scavengers substances on protein alterations induced by free radical production. Structural modifications were investigated by SDS-PAGE in reducing or non-reducing conditions. In vitro cytotoxicity assay was performed to test average toxic activities of BTHX-I. BALB/c Isogenic mice were immunized with irradiated or non-irradiated (native) forms of BTHX-I and antibody titers and isotypes were determined by ELISA method. Expression of murine cytokines was analyzed by using expression data obtained by quantitative real-time PCR (qPCR) assays. The results indicate that irradiation of proteins leads to significant structural modifications, and also changes the cytokines profile during immunization process, regarding a suitable approach to new immunogenic production.

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