Search

Objective: To determine whether Povidone-iodine was toxic to brain tissues by rinsing the cerebral cortex of New Zealand rabbits with Povidone-iodine Solution of different concentrations. Methods: 12 New Zealand rabbits were randomly divided into 4 groups (Group A, B, C and D, 3 rabbits each group). In each group, the left cerebral cortex of rabbits was rinsed with physiological saline after the craniotomy; in Group A and B, the right cerebral cortex of rabbits was also locally rinsed with Povidone-iodine Solution (0.01%), in Group C and D, the right cerebral cortex of rabbits was also locally rinsed with Povidone-iodine Solution (0.05%). In Group A and C, the rabbits were sacrificed at D3 after the operation, and the brain was taken out; and in Group B and D, the rabbits were sacrificed at D7 after the operation, and the brain was taken out. Under the optical and electron microscope, the change in micro-structure of brain tissues was observed in each group. Results: In each group, there was no epilepsy or paralysis during and after the operation. At the treatment side of physiological saline, there was no significant cell damage in the local brain tissues. At the treatment side of Povidone-iodine Solution, there was no cell apoptosis or degeneration in the local brain tissues. Conclusion: The Povidone-iodine Solution (0.05% and 0.01%) was toxic to brain tissues, with a more obvious damage of brain tissues for the former concentration. The histological sign was more serious at D7 than that at D3.

The single electron impact ionization cross sections of Ar+, Kr+, In+ and Ge+ were measured on the improved electron-ion impact apparatus at Fudan University. The Ar+, Kr+ and In+ experimental results are in good agreement with data from other laboratories. The cross section of Ge+ was measured for the first time. The experimental results indicate that the indirect ionization process gives a larger contribution to the total ionization cross section of In+, as compared to the other three targets. The experimental data were compared with our Distorted-Wave-Born-Exchange-Approximation (DWBEA) calculation, the Lotz formula, and Configuration-Averaged-Distorted-Wave (CADW) calculations.

A C+60 ion beam was extracted from a hollow cathode ion source (model 911A). The mass spectra of 6 keV C60 and its fragments have been measured. Only those clusters with an even number of C atoms were observed and the largest one was C84. The result shows that the fragment ion beam has an exponential distribution, which is similar to that of C+60–H2(He) collision experiments. We also have extracted C‐cluster negative‐ion beams from a Middleton 860 sputtering source. With a graphite cathode, we have observed many cluster ions which were not previously reported. For a C60/C70 cathode, we have obtained a stable C−60 ion beam with current of about 1 nA. The spectra of the negative ions are complicated due to the existence of the Cs–Cn clusters.

By using a distorted-wave Born exchange approximation, the direct ionizarion cross section of boron-like ions by electron impact have been calculated. The interferences between direct and exchange amplitudes make important contribution in the process of ionization. The calculated results indicate that the "Natural Phase" approximation is better than the "Maximum Interference" approximation, while the latter agrees better with experiments for some other species of ions. Compared with Coulomb-Born approximation of Moores et al., our calculation gives better agreement with the experiment data available.

The C60+ fragmentation caused by electron collision has been studied with a 911A ion source of a mini-separator at the Accelerator Laboratory of Fudan University. The mass spectrum of the fragments has been measured. We found that the fragments contain even number of carbon atoms and the strength of the beam current shows an exponential distribution. Our results show that the fragmentation caused by electron collision has some similarities to that of atomic collision at the energy about 300 keV.