Automated production of 64Cu prepared by 18?MeV cyclotron

⁶⁴Cu (T_1/2?=?12,7?h, ??^? 37,1?%, ??⁺ 17,9?%, EC 41?%) is a useful radioisotopes for positron emission tomography radiopharmaceutical. We used the reaction route ⁶⁴Ni(p,n)⁶⁴Cu for the ⁶⁴Cu preparation. A basic disadvantage of this route, a high price of the enriched target material, was eliminated by using very simple recycling procedure. Compact solid target irradiation system was installed at the end of the external beam line of the IBA Cyclone 18/9 cyclotron. In this paper, the irradiation of ⁶⁴Ni target and separation of ⁶⁴Cu from a target material is described. The separation was achieved by anion exchange chromatography with HCl as a elution solution. The distribution ratio for different HCl concentrations on Bio-Rad AG1-X8 and elution profile of ⁶⁴Cu were investigated. ⁶⁴Cu production rate for 100?mg ⁶⁴Ni of 99.09?% purity (ISOFLEX) on gold target was 104?MBq/??Ah. The activity of the product was checked by ionisation chamber (Curiementor), gamma spectrometry using a HPGe detector and liquid scintillation counting using the triple-to-double coincidence ratio method. The separation process of ⁶⁴Cu was made in a home-made separation module.     

Interactions and Encapsulation of Vitamins C,B3, and B6 with Dendrimers in Water

Titrations of commercial diaminobutane (DAB) and polyamidoamine (PAMAM) dendrimers by vitamins C (ascorbic acid, AA), B₃ (nicotinic acid), and B₆ (pyridoxine) were monitored by ¹H NMR spectroscopy using the chemical shifts of both dendrimer and vitamin protons and analyzed by comparison with the titration of propylamine. Quaternarizations of the terminal primary amino groups and intradendritic tertiary amino groups, which are nearly quantitative with vitamin C, were characterized by more or less sharp variations (Δδ) of the ¹H chemical shift (δ) at the equivalence points. The peripheral primary amino groups of the DAB dendrimers were quaternarized first, but not selectively, whereas a sharp chemical‐shift variation was recorded for the inner methylene protons near the tertiary amines, thereby indicating encapsulation, when all the dendritic amines were quaternarized. With DAB‐G5‐64‐NH₂, some excess acid is required to protonate the inner amino groups, presumably because of basicity decrease due to excess charge repulsion. On the other hand, this selectivity was not observed with PAMAM dendrimers. The special case of the titration of the dendrimers by vitamin B₆ indicates only dominant supramolecular hydrogen‐bonding interactions and no quaternarization, with core amino groups being privileged, which indicates the strong tendency to encapsulate vitamins. With vitamin B₃, a carboxylic acid, titration of DAB‐G3‐16‐NH₂ shows that only six peripheral amino groups are protonated on average, even with excess vitamin B₃, because protonation is all the more difficult due to increased charge repulsion, as positive charges accumulate around the dendrimer. Inner amino groups interact with this vitamin, however, thus indicating encapsulation presumably with supramolecular hydrogen bonding without much charge transfer.     

Preparation and characterization of nickel targets for cyclotron production of <Superscript>64</Superscript>Cu

The reaction route ⁶⁴Ni(p,n)⁶⁴Cu is very popular for the preparation of ⁶⁴Cu because its entrance channel is accessible at low energies and yield of reaction is quite high. However, a high price of the enriched ⁶⁴Ni is a disadvantage of this reaction path; hence, preparation of a chemically pure nickel targets for the production of ⁶⁴Cu using COSTIS (Compact Solid Target Irradiation System) is of a great research interest. In this paper, effects of boric acid, composition of electrolytic bath and electrochemical process conditions on the quality of nickel films deposited on 2 mm thick gold or platinum disc targets were investigated. Chemical purity of the electrodeposited nickel was measured by the Auger electron spectroscopy and the surface quality of targets was studied microscopically (SEM). A SRIM program was used for a thickness target calculation. COSTIS target station was installed at the end of the external beam line of the IBA Cyclone 18/9 cyclotron, and the irradiation surface of target was optimized. The target station has been equipped with Al or Nb window foil in the front of the target to degrade the beam energy to an optimal value.     

On estimations of dispersion of ratio block sequences

Using new characteristics of an infinite subset of positive integers we give some estimations of the dispersion of the related block sequence. Supported by VEGA Grant no. 1/4006/07.