Physiological effects of extremely high X-ray intensities and dosages on mice

The physiological effects of high-intensity x-irradiation (2 x 105 r/min.) and dosages of 1 x 106 r on mice (head and abdomen) were investigated. An increase in pulmonary and heart rates were observed. Electrocardiographic recordings after irradiation demonstrated reversal of wave components and increase of amplitudes. Blood counts present no changes except for a drop in leukocyte counts. Hemoglobin remained unchanged. A considerable increase in serum potassium was noted and some indications of methemoglobin production. Head-irradiated animals yielded a higher incidence of auricular congestion and brain hemorrhage in contrast to animals receiving abdominal irradiation.

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Eds Of Radioactive Particles By Self-Induced Fluorescence

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s042482010013479x ◽

1990 ◽

Vol 48 (2) ◽

pp. 238-239

Author(s):

Gregory L. Finch ◽

Richard G. Cuddihy

Keyword(s):

Electron Beam Irradiation ◽

Nuclear Reactor ◽

X Rays ◽

Reactor Accident ◽

Internal Radiation ◽

X Ray ◽

External Sources ◽

X Irradiation ◽

Available Information ◽

Individual Particles

The elemental composition of individual particles is commonly measured by using energydispersive spectroscopic microanalysis (EDS) of samples excited with electron beam irradiation. Similarly, several investigators have characterized particles by using external monochromatic X-irradiation rather than electrons. However, there is little available information describing measurements of particulate characteristic X rays produced not from external sources of radiation, but rather from internal radiation contained within the particle itself. Here, we describe the low-energy (< 20 KeV) characteristic X-ray spectra produced by internal radiation self-excitation of two general types of particulate samples; individual radioactive particles produced during the Chernobyl nuclear reactor accident and radioactive fused aluminosilicate particles (FAP). In addition, we compare these spectra with those generated by conventional EDS.Approximately thirty radioactive particle samples from the Chernobyl accident were on a sample of wood that was near the reactor when the accident occurred. Individual particles still on the wood were microdissected from the bulk matrix after bulk autoradiography.

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Improvement of the Detection Sensitivity of Edxrf Trace Element Analysis by Means of Efficient X-Ray Focusing Based on Strongly Curved Hopg Crystals

Advances in X-ray Analysis ◽

10.1154/s0376030800022515 ◽

1995 ◽

Vol 39 ◽

pp. 109-117

Author(s):

Burkhard Beckhoff ◽

Birgit Kanngießer

Keyword(s):

High Intensity ◽

Focal Plane ◽

Bragg Reflection ◽

Pyrolytic Graphite ◽

Trace Element Analysis ◽

Detection Sensitivity ◽

Element Analysis ◽

X Ray ◽

Wide Range ◽

Very High

X-ray focusing based on Bragg reflection at curved crystals allows collection of a large solid angle of incident radiation, monochromatization of this radiation, and condensation of the beam reflected at the crystal into a small spatial cross-section in a pre-selected focal plane. Thus, for the Bragg reflected radiation, one can achieve higher intensities than for the radiation passing directly to the same small area in the focal plane. In that case one can profit considerably from X-ray focusing in an EDXRF arrangement. The 00 2 reflection at Highly Oriented Pyrolytic Graphite (HOPG) crystals offers a very high intensity of the Bragg reflected beam for a wide range of photon energies. Furthermore, curvature radii smaller than 10 mm can be achieved for HOPG crystals ensuring efficient X-ray focusing in EDXRF applications. For the trace analysis of very small amounts of specimen material deposited on small areas of thin-filter backings, HOPG based X-ray focusing may be used to achieve a very high intensity of monochromatic excitation radiation.

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A Small-Angle X-Ray Scattering Study on Pre-Irradiated Malate Synthase. The Influence of Formate, Superoxide Dismutase, and Catalase on the X-Ray Induced Aggregation of the Enzyme

Zeitschrift für Naturforschung C ◽

10.1515/znc-1985-5-614 ◽

1985 ◽

Vol 40 (5-6) ◽

pp. 364-372 ◽

Cited By ~ 7

Author(s):

P. Zipper ◽

R. Wilfing ◽

M. Kriechbaum ◽

H. Durchschlag

Keyword(s):

Aqueous Solution ◽

Superoxide Dismutase ◽

Small Angle ◽

Malate Synthase ◽

X Ray ◽

X Ray Scattering ◽

X Irradiation ◽

The Mean ◽

Induced Aggregation ◽

Ray Scattering

Abstract The sulfhydryl enzyme malate synthase from baker’s yeast was X-irradiated with 6 kGy in air-saturated aqueous solution (enzyme concentration: ≃ 10 mg/ml; volume: 120 μl), in the absence or presence of the specific scavengers formate, superoxide dismutase, and catalase. After X-irradiation, a small aliquot of the irradiated solutions was tested for enzymic activity while the main portion was investigated by means of small-angle X-ray scattering. Additionally, an unirradiated sample without additives was investigated as a reference. Experiments yielded the following results: 1. X-irradiation in the absence of the mentioned scavengers caused considerable aggregation, fragmentation, and inactivation of the enzyme. The dose Dt37 for total (= repairable + non-repayable) inactivation resulted as 4.4 kGy. The mean radius of gyration was found to be about 13 nm. The mean degree of aggregation was obtained as 5.7, without correction for fragmentation. An estimation based on the thickness factor revealed that about 19% of material might be strongly fragmented. When this amount of fragments was accordingly taken into account, a value of 7.1 was obtained as an upper limit for the mean degree of aggregation. The observed retention of the thickness factor and the finding of two different cross-section factors are in full accord with the two-dimensional aggregation model established previously (Zipper and Durchschlag, Radiat. Environ. Biophys. 18, 99 - 121 (1980)). 2. The presence of catalytic amounts of superoxide dismutase and/or catalase, in the absence of formate, during X-irradiation reduced both aggregation and inactivation significantly. 3. The presence of formate (10 or 100 mᴍ) during X-irradiation led to a strong decrease of aggregation and inactivation. This effect was more pronounced with the higher formate concentration or when superoxide dismutase and/or catalase were simultaneously present during X-irradiation. The presence of formate also reduced the amount of fragments significantly. 4. The results clearly show that the aggregation and inactivation of malate synthase upon X-irradiation in aqueous solution are mainly caused by OH·; to a minor extent O·̄2 and H2O2 are additionally involved in the damaging processes.

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