The effects of molecular size of humic acid (HA) on the interaction affinity with60Co and241Am have been examined with respect to different molecular size fractions which were isolated from the Aldrich Chemical's HA into 5000-30000, 30000 -100000 and >100 000 in molecular weight (MW), while the functional groups of the molecular size fractions have been characterized with respect to their FTIR spectral characteristics. The HA of >100000 MW which was dominated with aliphatic functional groups did not take part in the interaction with60Co and241Am. The HA of 30000-100000 MW was dominated with both aromatic COOH and phenolic OH, and it perferentially interacted with60Co and241Am. However, 241Am did not interact with the HA of 5000-30000 MW which was mainly dominated with aromatic COON, while60Co interacted. Such effects of molecular size of HA may be caused by more than two different functional groups concerning to the complexation and/or steric hindrance around the functional groups.
Caatinger (Mimosa acutistipula Benth), which has been a popular wood among the people in north east part of Brazil, was analyzed using PIXE (proton induced X-ray emission) . The wood sample was divided into three parts, center, inner and outer side of the wood. Using the wood slice of each part, Na, Mg, Al, Si, P, S, Cl, K, Ca, Ti, Mn, Fe, Cu, Zn, As, Se, Br, Rb, Sr, Y, Ru and Pb were detected. When the wood slices were decomposed with nitric acid, Co and Ni were able to be determined. Two samples, non-destructive and chemically treated sample, of heartwood and sapwood showed the similar concentration of the elements. There was a discrete change of the accumulated elements between heartwood and sapwood. Most of the elements detected were tended to be concentrated at sapwood, whereas Ca, Cu and Sr were concentrated at heartwood. At center part, especially, Na, Mg, Fe and Sr were accumulated. Since most of the heartwood and sapwood is dead, discrete change of the element concentration suggests some element movement across the annual ring at heartwood formation.
In 1978, one of the authors (H. Oyamada) developed an apparatus which can remove131I from the urine on the basis of the action of anion exchange resin (IRA 400) after high dose radioiodine treatment for metastatic thyroid cancer patients. This apparatus has been slightly modified by applying a cartridge filled with IRA 400. This newly modified apparatus was tested for its efficiency in removing131I from the urine on 4 consecutive cases. The removal efficiency for an entire term of hospitalization of each patient ranged from 99.98% to 99.83%, indicating a very high efficiency.