Human lifespan

SWS/SWA, in particular, may play an important role in somatic and cognitive restoration, including the consolidation of certain forms of procedural and declarative memory. A substantial diminution in the amount of SWS/SWA occurs across the human lifespan. This decline is beginning already in adolescence and middle-aged adults have only 25% of the SWS observed in young adults, whereas the elderly have almost none. While the clinical importance of these phenomena is unknown, it is reasonable to speculate that they may be related to the increase of sleep complaints associated with aging. 

The multimedia model present in the 2 FUN tool was developed based on an extensive comparison and evaluation of some of the previously discussed multimedia models, such as CalTOX, Simplebox, XtraFOOD, etc. The multimedia model comprises several environmental modules, i.e. air, fresh water, soil/ground water, several crops and animal (cow and milk). It is used to simulate chemical distribution in the environmental modules, taking into account the manifold links between them. The PBPK models were developed to simulate the body burden of toxic chemicals throughout the entire human lifespan, integrating the evolution of the physiology and anatomy from childhood to advanced age. That model is based on a detailed description of the body anatomy and includes a substantial number of tissue compartments to enable detailed analysis of toxicokinetics for diverse chemicals that induce multiple effects in different target tissues. The key input parameters used in both models were given in the form of probability density function (PDF) to allow for the exhaustive probabilistic analysis and sensitivity analysis in terms of simulation outcomes [71]. 

Ohayon M, Carskadon M, Guilleminault C, Vitiello M (2004) Meta-Analysis of quantitative sleep parameters from childhood to old age in healthy individuals developing normative sleep values across the human lifespan. Sleep 21 1255-1273... 

In a recent review of the chronic diseases that contribute most importantly to limiting human lifespan, Fries and Crapo (1) list the six diseases shown in Table I. It is interesting that there is beginning to be evidence for an important contribution of free radical processes in many of these six diseases, and much of this evidence is quite new. I will briefly review the evidence for free radical involvement in each of these processes. 

Figure 16-1 shows most energy uses on earth except for nuclear, tidal, and geothermal power. All the energy shown is renewable. The top six categories are renewable within a human lifespan, but the bottom category, including... 

Beaudouin R, Micallef S, Brochot C (2010) A stochastic whole-body physiologically based pharmacokinetic model to assess the impact of inter-individual variability on tissue dosimetry over the human lifespan. Regul Toxicol Pharmacol 57 103-116... 

The principles to be discussed comprise the cornerstone of modern science, and their continuous application has resulted in many benefits of modern medicine that we all enjoy. Application of statistics to science and medicine has most likely contributed to the increased human lifespan observed in recent decades. However, more recently, it has also been responsible for much of the concern we have over adverse effects of modern chemicals and pesticides. Since all of the data to answer these issues are expressed as probabilities, using the language of statistics, what does using statistics really mean How should results be interpreted ... 

Accidental deaths are those that include diseases as well as traumatic injuries. As the BU matures, it will usually develop better defenses against diseases and better avoidanee of traumatic injuries. So, by the time the BU reaches maturity, the risk of death is usually minimal. Thereafter, the risk increases slowly as the BU ages. Deaths toward the end of the natural lifespan can usually be considered to be both accidental and genetic. Clearly, at least at this point, there are no known means to extend the human lifespan beyond 120 years. In the case of the annual plant, such as corn or marigolds, death begins shortly after the seeds ripen. 

Lehmer, 1. R, Gluck, J. and Laska, M. (1999). Odor identification, consistency of label use, olfactory threshold and their relationships to odor memory over the human lifespan. Chemical Senses, 24,337 6. 

To the contrary, there is significant likelihood that public funding of science will be reduced, since politicians will no longer see it as vital to national security. Since we all obviously believe that science has more to offer to the benefit of society now than it ever did in the past, we need to persuade the policy makers that peaceful international competition in non-military arenas, such as those listed earlier by Prof. Whitesides (manufacturing, information, environment), is at least as beneficial as providing national security by military means was in the past. Judging by mankind s past record, we only have a limited period of essentially effortless military security without major threats on the horizon, but one can hope that this period will be long on the scale of human lifespan, and science needs to adjust to the political conditions that will prevail in this period. 

Fig. 3 Proposal effect of flavonoids on human lifespan and the xenohormesis theory. The theory states that phytochemicals (e.g., flavonoids) can communicate a stress signal present in the plant to different organisms, when they are consumed as foocL This signal leads to the activation of sirtuins involved in lifespan...

Even if it should be impossible to extend the human lifespan much beyond 100 years, it would still be a great achievement to cut the incidences of the major degenerative diseases drastically, so that more people might live healthier and longer lives. Hence, the groups of people who have lower-than-normal rates of these diseases are noteworthy. 

---