Ham factors

The Jahn-Teller community has lost one of our illustrious members with the death of Frank Ham on December 12, 2002. Phrases such as The Ham effect , Ham factors and Ham quenching are terms that frequently appear in any article in which the Jahn-Teller effect or vibronic coupling is involved. I would like to record my own personal thoughts about Frank and on behalf of the whole Jahn-Teller community. 

The beauty of Ham s theory is its simplicity. The Ham factors for any particular problem can be classified by symmetry. This means that any other operator which is a function of the Ua2 will be reduced by the same factor. Note that Ham s treatment implies that that the linear coupling is large compared to the additional terms in the Hamiltonian that are subsequently evaluated as perturbations of the ground vibronic energy levels. 

Hamamelis [84696-19-5] Hamamelis virginiana Ham curing Hammerhead ribozyme Hammer mills Hammett equation Hamposyl 0 Hamposyl C Hamposyl C-30 Hamposyl L Hamposyl L-30 Hand factor Hand lay-up... 

Fig. 1. Properties of foods near 2.45 GHz as a function of temperature, where A represents distilled water B, cooked carrots C, mashed potatoes D, cooked ham E, raw beef F, cooked beef and G, com oil (a) dielectric constants and (b) load factors, e = etan6 (32).

A review by Bailey and Swain ( ) cited several references which indicated nitrite was responsible for cured meat flavor. These same authors presented chromatograms of volatiles from cured and uncured hams and while the chromatograms were similar, some quantitative differences led to the conclusion that the major difference due to nitrite was its reactivity to retard lipid oxidation. Greene and Price ( ) suggested, however, that sodium chloride was the major factor responsible for cured meat flavor rather than sodium nitrite or an absence of lipid oxidation. It has been concluded from other recent work (2) that nitrite was necessary to produce a typical ham aroma and flavor as well as to retard the development of off-odors and flavors during storage of cooked cured meat. 

Kramer, H.J., W.A. van den Ham, W. Slob, and M.N. Pieters. 1996. Conversion factors estimating indicative chronic no-observed-adverse-effect levels from short-term toxicity data. Regul. Toxicol. Pharmacol. 23 249-255. 

Y, the Ham quenching factor, corresponds to the vibrational overlap of the displaced Jahn-Teller potentials. Assuming Harmonic potentials, Y is given by... 

It was observed that CHO cells which had entered a stationary phase in Ham s F10 medium could be stimulated to undergo a further round of division by changing the medium. The growth limitation was not a serum factor but was traced to a deficiency in isoleucine which is present in Ham s F10 medium at only about 5-10% its concentration in other media (Ley and Tobey, 1970 Tobey and Ley, 1970). 

The inverse-sixth-power van der Waals interaction is never likely to be strong compared with thermal energy. When surface-to-surface separations are small compared with particle size, these dispersion forces can become significant factors in organizing molecules. These spectral data give A Ham 2.5 kTroom 10 x 10 14 ergs or 10-20 J or 10 zj.10 Momentarily neglecting the limitations of a continuum picture, what would this A Ham mean for two parallel surfaces with an area L2 = 1 nm2, / = 0.22 nm = 2.5 A apart ... 

White JV, Ham RJ, Lipschitz DA, et al. Consensus of the Nutrition Screening Initiative Risk factors and indicators of poor nutritional status in older Americans. Journal of the American Diabetic Association 91 783-787,1991. 

Ham, R.G. 1981. Tissue growth factors. In Handbook of Experimental Pharmacology. R. Baserga, ed., Springer Verlag, New York, p. 13. 

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