They try to understand the nature of aging and they develop treatments to reverse aging processes or to at least slow them down, for the improvement of health and the maintenance of youthful vigor at every stage of life. Those who take advantage of life extension findings and seek to apply them upon themselves are called "life extensionists" or "longevists". The primary life extension strategy currently is to apply available anti-aging methods in the hope of living long enough to benefit from a complete cure to aging once it is developed. Location
Before about 1930, most people in Western countries died in their own homes, surrounded by family, and comforted by clergy, neighbors, and doctors making house calls. By the mid-20th century, half of all Americans died in a hospital. By the start of the 21st century, only about 20–25% of people in developed countries died outside of a medical institution. The shift away from dying at home towards dying in a professional medical environment has been termed the "Invisible Death". This shift occurred gradually over the years, until most deaths now occur outside the home. Psychology
Death studies is a field within psychology. Many people are afraid of dying. Discussing, thinking about, or planning for their own deaths causes them discomfort. This fear may cause them to put off financial planning, preparing a will and testament, or requesting help from a hospice organization. Different people have different responses to the idea of their own deaths.
Each PBGS subunit consists of a ~300 residue αβ-barrel domain, which houses the enzymes active site in its center, and a >25 residue N-terminal arm domain. Allosteric regulation of PBGS can be described in terms of the orientation of the αβ-barrel domain with respect to the N-terminal arm domain. Each N-terminal arm has up to two interactions with other subunits in a PBGS multimer. One of these interactions helps to stabilize a "closed" conformation of the active site lid. The other interaction restricts solvent access from the other end of the αβ-barrel. In the inactive multimeric state, the N-terminal arm domain is not involved in the lid-stabilizing interaction, and in the crystal structure of the inactive assembly, the active site lid is disordered. Allosteric regulators
As a nearly universal enzyme with a highly conserved active site, PBGS would not be a prime target for the development of antimicrobials and/or herbicides. To the contrary, allosteric sites can be much more phylogenetically variable than active sites, thus presenting more drug development opportunities.Phylogenetic variation in PBGS allostery leads to the framing of discussion of PBGS allosteric regulation in terms of intrinsic and extrinsic factors. Intrinsic allosteric regulators
Magnesium
The allosteric magnesium ion lies at the highly hydrated interface of two pro-octamer dimers. It appears to be easily dissociable, and it has been shown that hexamers accumulate when magnesium is removed in vitro.