In primitive societies, old age was frequently valued. (Simmons, 1945). Older persons often provided knowledge, experience and institutional memory that was of adaptive – even survival – value to their societies. Although nomadic groups in various parts of the world abandoned the old and disabled when safety and security were at stake, overall older people were venerated. However, as the number and percentage of older persons, especially the frail and demented, increased, the perception grew that they were burdens to their families and society. This perception became widespread as societies shifted from agrarian economies, where older men had traditionally owned the land, to industrialized economies, where work was no longer centered in the home and older persons lost their authority.

Since 1955, when I first became involved in the field, there has been much progress in geriatric psychiatry. I would like to add here some general, even philosophic, considerations to this very important discipline; I offer these as a series of messages to keep in mind as we approach the 21st century. While we pursue our specific interests as psychogeriamcians, we must also keep in mind these more general issues and work toward a philosophy of individual and societal aging and longevity, drawing on both Eastern and Western thought.

Nanocrystalline diamond thin films of sub-micron thickness have been covalently modified with DNA oligonucleotides. Quantitative studies of hybridization of surface-bound oligonucleotides with fluorescently tagged complementary and non-complementary oligonucleotides were performed. The results show no detectable nonspecific adsorption, with extremely good selectivity between matched and mismatched sequences. Impedance spectroscopy measurements were made of DNA-modified boron-doped nanocrystalline diamond films. The results show that exposure to non-complementary sequences induce only small changes in impedance, while complementary DNA sequences produce a pronounced decrease in impedance. The combination of high stability, selectivity, and the ability to directly detect DNA hybridization via electrical means suggest that diamond may be an ideal substrate for continuously-monitoring biological sensors.