International Journal of PIXE

Trace elements play important roles in cells. Nuclear techniques as traditional PIXE, SPM and SR-XRM provide solid tools for quantitative element analysis. The article presents element-distribution maps of endometrium, nerve cell and relative quantity tables. Advantages of PIXE, SPM and SR-XRM techniques, especially in application to cell biology, are discussed. PIXE has a large beam and is convenient in measuring a large quantity of samples. SPM gives element-distribution maps owing to its high resolution. SR-XRM tells quantity of elements by its good sensitivity and nondestructive irradiation. The combination of PIXE, SPM and SR-XRM demonstrates that Zn is a component of cell membrane and is proved to be a complementary way which will open vast vistas for cell analysis.

Thick targets of Li₂B₄O₇ containing different concentrations of S have been irradiated with 0.8 to 3.0 MeV protons and 1.0 to 5.0 MeV Ar ions and the K X-ray yields of the S and one projectile (Ar) measured. The K X-ray production cross sections deduced from the measured yields, show a strong dependence on the S concentration in the case of the Ar bombardments. This effect is interpreted as being a consequence of the double-scattering mechanism occurring in the Ar-S collision system.

Cu K X-ray spectra for a copper target bombarded with ion beams of 1.4 ions, 2. 8 ions, and 3.0 MeV-Si⁺ ions have been measured with a Si(Li) detector. It is found that the Cu K X-ray spectrum for ion bombardments is almost same as that for C⁺ ion bombardments, whereas the spectrum for Si⁺ ion bombardments has a broad peak of MO X-rays in the low-energy region. The values of K_α/K_α+β for the Cu K X-rays are very close each other within the experimental uncertainty in these three cases. Thus, no multi-ionization effect is observed in the K X-ray emission by beam bombardments.

Ca-DTPA and Zn-DTPA were injected intraperitoneally into rats with a dose of 30 or 300 µmol/kg. The blood was collected from the tail vein just before the injection, 3, 6 and 24 hours after the injection. and centrifuged 10 separate the plasma. These plasma samples were analyzed by PIXE at Nishina Memorial Cyclotron Center.

Sodium, potassium, calcium, iron, copper and zinc were detected in the plasma. Ca-DTPA significantly lowered the concentration of zinc, while no significant changes were observed in the other metals. Zn-DTPA did not lower any metal concentrations, but a significant increase of plasma zinc was observed.

In conclusion, Ca-DTPA was confirmed to induce hypozincemia, which may be the cause of fetal injuries such as abortion, fetal death and malformation. Zn-DTPA was suggested not to induce any deficiencies of essential metals.

Vascular cell adhesion molecule-1 (VCAM-1) is transiently expressed on vascular endothelial cells in response to cytokines. It plays a major role in the adhesion of leucocytes to the endothelium by interaction with its ligand VLA-4, a member of the β1 integrin family. We measured the serum concentration of the soluble VCAM-1 (sVCAM-1) in 114 patients with acute myocardial infarction (AMI) and 37 normal controls by enzyme-linked immunoassay in comparison with trace element concentration. sVCAM-1 levels were markedly higher (mean± SD=833.2±328.9 ng/ml) in the sera of patients with AMI than in normal controls (mean±SD= 549.5±188.8 ng/ml, p<0.001). Using PIXE we also determined concentration of magnesium, manganese, iron, copper, zinc, selenium, and calcium in sera of 43 patients with AMI. There were no clear correlation between the sVCAM-1 concentration and the magnesium, manganese, copper, selenium. But there were significant correlation between the sVCAM-1 concentration and the zinc, calcium (p<0.05).

Concentration of In impurity doped in GaAs semiconductor was determined by PIXE method non-destructively using a plate target. The concentration of In in the range from 0.05 to 1 wt.% in GaAs crystals is given from PIXE peak intensities by [In] (wt.%)=(0.39±0.06)×In Kα/ (Ga Kβ+As Kα).

Aerosols collected in Seville during the winter of 1985 have been analyzed by PIXE, and the concentrations of elements heavier than Mg have been obtained. A preliminary principal component analysis has been performed on a limited data set, and three main sources of contamination have been identified. The correlation of these sources with meteorological variables has been studied.

Partial K-x ray production cross sections of dysprosium, erbium and lutetium by proton and ³He-ion impact have been measured over the incident energy range of 3-40 MeV/amu. It is found that the measured ionization cross sections become larger in comparison with the prediction of PWBA theory and agree well with the ECPSSR theory in the wide energy region. This fact means that relativistic effect of inner-shell electrons is the most predominant among many effects such as the energy loss and the Coulomb deflection of the projectile and also the effects of polarization and increased binding energy of orbital electrons in the perturbed stationary states.