Aging, theories

Carfagno and Gibson, A review of equipment ageing theory and technology, EPRI NP-1558, Electric Power Research Institute, Palo Alto, CA, USA, September 1980. 

Ya.B. s unpublished 1943 paper, The Age Theory of Neutron Moderation, is closely related to his studies of the war period. The age theory, developed independently of E. Fermi, forms the basis for calculation of a reactor by slow neutrons. It was in this paper that the famous age equation was obtained. 

Aigner T, Rose J, Martin J, Buckwalter J. Aging theories of primary osteoarthritis from epidemiology to molecular biology. Rejuvenation Res. 2004 7 134-145. 

Although it is true that abnormal proteins increase with age, most of them are a result of posttranslational changes. An example is the various isoforms of creatine kinase (CK). Here, the major isoenzyme, CK-MM (isoform CK-33), is normally synthesized in the heart and skeletal muscle. However, after its release into the circulation, carboxypeptidase hydrolyzes the terminal lysine from one of the M-peptides to form CK-32. Subsequent hydrolysis of the terminal lysine from the second M-peptide produces the third isoform, CK-3i (W8). Numerous similar posttranslational proteins are produced. Hence, the presence of abnormal proteins per se does not support this aging theory. 

It is also of importance to note that the major histocompatability complex is genetically linked with the antioxidant enzyme, superoxide dismutase (W9). Thus, it appears that there exists a relationship between the free radical and immune aging theories. As noted below, immunity is also influenced by the endocrine system. 

More recent studies also suggest that increased IL-6 production is associated with age-related depression (D6) and disability due to muscle atrophy and/or various specific diseases (F8). Moreover, Straub et al. (S30) suggest that increased IL-6 levels may be secondary to diminished levels of the steroid hormone, dehy-droepiandrosterone (see below under neuroendocrine aging theory). The pathophysiologic role of IL-6 in human disease has been recently reviewed (P7). 

Since various neuroendocrine abnormalities increase with age, the neuroendocrine aging theory has received considerable attention. Nevertheless, some of these abnormalities are secondary phenomena, and others are due to disorders... 

There are approaches to analyses of turbulent combustion that, although not deductively based on the Navier-Stokes equations, nevertheless appeal to concepts of coherent structures [68], [69]. We shall not have space here to present these approaches and must refer instead to reviews [18], [27], [40]. These methods share some aspects in common with age theories of stirred reactors [19], theories that we also shall forego discussing for the sake of brevity. Instead, we shall consider a promising approach to the theoretical analysis of turbulent diffusion flames. 

However, an alternative explanation may be found in the Sequential Aging Theory proposed by Chai and McCmm [1980]. The authors postulated that at a given T and t, the viscoelastic elements with relaxation times equivalent to t will be aging, but that elements with x < t will already have reached equilibrium and those with X > t will not yet have begun to move towards equilibrium. Thus in the PVME/PS case the more flexible PVME, which will also be closer to its own Tg, will possess more elements with shorter X than the PS. Consequently the PVME relaxation spectram will tend to move more rapidly towards equilibrium than the PS and so would age more rapidly. This idea will require further testing. 

Lipid oxidation in vivo is correlated with many diseases and is a base for the aging theory. The oxidation of food lipids depends on their FA composition but mostly on the pro- and antioxidant status in the food matrix, as well as on external factors such as light, oxygen pressure, and temperature. Lipid oxidation results in... 

Nevertheless, ever since the theory of evolution became popular, there have been attempts to harmonize the biblical account of Creation with evolution— what is known as"theistic evolution."ln short, theistic evolution holds that God used the evolutionary process to bring about creation. The two most common theories of theistic evolution are the Gap Theory and the Day-Age Theory. 

Proponents of this theory contend that the six days of Genesis 1 were actually long periods of time— ages—that correspond to the major periods of geological history, as defined by evolutionists. Day-Age Theory proponents apply the third definition of youm ("an indefinite period of time") to the days of Genesis 1, and support this with 2 Peter 3 8 "One day is with the Lord as a thousand years and a thousand years as one day."They also insist that too much activity took place on the sixth day (Genesis chapter 2) to fit into a single 24-hour day. 

Again, the Day-Age Theory satisfies neither the creationists nor the evolutionists. 

For more details on this subject, see Theistic Evolution and the Day-Age Theory, by Richard Niessen, published by the Institute for Creation Research. http //vmw. icr.org/pu bs/im p/i m p-081. htm... 

Robertson, R. E., Simha, R., and Curro, J. G., Multiple temperature steps a further test of an aging theory for polymer glasses. Macromolecules, 21,3216-3220 (1988). 

McCrum, N. G., The interpretation of physical ageing in creep and DMTA from sequential ageing theory, Plast. Rubber Compounds Proc. Appl., 18, 181-191 (1992). 

This paper, though written after Wigner came to Chicago, is largely based on calculations performed at Princeton in support of the experiments reported in papers 5-9. This is the earliest use by Wigner of Fermi s age theory for the slowing down of fast neutrons. 

Hemmerich, K., General Aging Theory and Simplified Protocol for Accelerated Aging of Medical Devices, Medical Plastics and Biomaterials, July/August 1998, pp. 16-23. 

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