Instructions for authors
Please provide a short abstract of 100 to 250 words. The abstract should not contain any undefined abbreviations or unspecified references.
Genes and Aging
Genes may be regarded in at least two quite distinct ways in relation to processes of aging. They are units of genetic transmission from parent to offspring and, also, intracellular agents whose products interact with environmental forces to control development, differentiation, metabolism, and degeneration. Much of this chapter will deal with the results of genetic transmission, that is, with genetic similarities and differences between individuals, present throughout their life-spans. I will attempt to demonstrate that the patterns of the aging of individuals carrying an identical array of genes will show greater similarity than will the patterns of the aging of individuals carrying different assortments of genes. To do this, I will have to deal mostly with genetically controlled animals, and I will try to bring home to you why and how these animals with specific genotypes have become important in research on the biology of aging.
DESIGN CONSIDERATION TO PPM KLYSTRONS FOR INDUSTRIAL LINAC
Toshiba has been developing the C-band and X-band Periodic Permanent Magnet (PPM) focused klystron in collaboration with KEK and manufactured prototypes for the JLC project. [1] The PPM klystron has an advantage to enhance the total efficiency as a result of eliminating the electric power for the focusing magnet. From experience on the development the PPM focused klystrons for the JLC project, we plan to apply the PPM focused klystron to the medical and industrial linac. The periodic magnet focusing scheme has some technical difficulties such as stop band voltage. To design the PPM klystron for the medical and industrial linac, it is necessary to give heed to electron beam instability; so that the tube parameters of the PPM focused klystrons have some constraints. The size of the accelerator system is substantially reduced if a PPM focused klystron is used. The majority of medical and industrial linacs use frequencies of S-band range. We discuss the availability of the S-band PPM focused klystron in this paper.