Herndon model

Method of Qarbalena and Herndon The Garbalena and Herndon model applies to alkanes (C2-C15) [18], It is based on atom contribution and contributions of atom pairs in which the atoms are two bonds apart. The GCM equation is ... 

Simpson-Herndon model, and the conjugated-circuits model. The calculation of the KSC can be performed with recurrence relationships, matrix methods, and explicit combinatorial expressions derived for a large number of classes of conjugated hydrocarbons various classes of cata-condensed benzenoid hydrocarbons honeycomb lattice strips polymers. 

L17. Lubbesmeyer, H. J., Woodson, L., Traber, L. D., Flynn, J. T., Herndon, D. N., andTraber, D. L., Immunoreactive atrial natriuretic factor is increased in ovine model of endotoxemia. Am. J. Physiol. 254, R567-R571 (1988). 

Findlay JBC. Membrane Protein Models, Bios Scientific Publishers, Herndon, VA, 1996. 

Garbalena, M., and W. C. Herndon, Optimum Graph-Theoretical Models for Enthalpic Properties of Alkanes. J. Chem. Inf. Comput. Sci., 1992 32, 37-42. 

In fact Randic [73] proposed expressions like that of (6.2.4) independently of a development from the Herndon-Simpson model. His idea may have been to graph-theoretically quantify the qualitative classical aromatic-sextet ideas of Clar [74]. The coefficients of 6(G), i0(G) and that of a particular combination of the conjugated 14-circuit invariants were treated as empirical parameters. The derived parameters of Eq. (6.2.4) compare to only within a factor of 50% to Randic s parameters. But the comparison especially for the two larger parameters is even closer (to 20%) and is really somewhat remarkable considering that Randic s values were obtained by fitting to SCF-MO results [62],... 

A number of computational approaches to the (G) have been developed and there have been widespread applications of the conjugated-circuits model, motivated both from Herndon s and from Randic s approaches. The applications extend even much beyond benzenoids. This is reviewed elsewhere by Randic et al. [76],... 

Herndon and co-workers4 developed a model for predicting regioselectivity which has been adapted to periselectivity problems by Paddon-Row.64 It makes two assumptions (a) the two reaction partners approach in parallel planes and (b) the distance between these planes is the same in all reactions. The second is a serious constraint, which explains a success rate of 14 correct predictions out of 17 cases (82%). The model is more reasonable when applied to regioselectivity, where two different orientations of the same cycloaddition are compared (122 correct predicttions in 133 cases, i.e. 91.7%).5 Nonetheless, to the best of our knowledge, FO theory provides the only simple way to study periselectivity available at present. 

It must be admitted that 0-0 and a-n switch processes are of limited stereochemical interest. Given the prototypes (92) or (97), the reactions must be syw-stereospecific any other stereochemical result would in fact be used as a criterion of a multi-step mechanism. This is also true of the mixed types, (101)-(104). But these reactions are exceedingly useful as models for orbital-based calculations or estimates of free energies of activation, with the use of extended HMO theory. The four- or six-center process (92)-(104) does not appear to be more complex than the Diels-Alder reaction, which has been investigated theoretically (Herndon and Hall, 1967). 

Fig. 2 Graf ical modeling of the generation of permutation integrals of Herndon [12] structure-resonance theory in case of an ra-cene yj involves permutation of (4i + 2), pi-electtons.

Herndon, W.C. and Szentpaly, L.V. (1986) Theoretical model of activation of carcinogenic polycyclic benzenoid aromatic hydrocarbons. Possible new classes of carcinogenic aromatic hydrocarbons. 

D Amico TA, Massey M, Herndon JE 2d, Moore MB, Harpole DH Jr. A biologic risk model for stage I lung cancer immunohistochemical analysis of 408 patients with the use of ten molecular markers. J Thorac Cardiovasc Surg 1999 117 736-743. 

The extension of independent electron treatments—e.g. of the type proposed by Huckel for n systems —to sigma systems, and in particular to hydrocarbons, has a long and well-known history. The early treatments used an orthonormal basis of atomic or bond orbitals with parametrized coulomb energies and interaction matrix elements restricted to nearest neighbours only. The most attractive approximation of this kind, proposed by Hall and Lennard-Jones in 1951, is the equivalent bond orbital (EBO) model, which has been used extensively since, with variations due mainly to Lorquet, Brailsford and Ford, Herndon, Murrell and Schmidt, and Gimarc . The conceptual consequences of such a treatment, in particular the phenomenon of -conjugation in saturated hydrocarbons, have been discussed in detail by Dewar ... 

Although we shall not use them within the context of this chapter, one must mention the independent electron models of hydrocarbons, which use an AO basis. References to earlier work can be found in the papers by Klopman and Herndon and attention is drawn to Hoffmann s extended Huckel theory, which is by far the most important independent electron treatment available The latter has proved extremely useful for the interpretation of PE spectra, but is a bit cumbersome for perturbation treatments, because it makes use of a non-orthogonal basis of AOs. 

In 1973 William Herndon put forward a resonance-theoretical model, according to which he was able to calculate the resonance energies of benzenoid hydrocarbons with accuracy tantamount to the best (in that time) molecular-orbital theories [31]. Let it be mentioned that similar ideas were proposed by Simpson in 1953 [32], but in that time had little impact. 

Cox, C.S., Zwischenberger, J.B., Traber, L.D., Traber, D.L., and Herndon, D.N. 1991. Use of an intravascular oxygenator/carbon dioxide removal device in an ovine smoke inhalation injury model. ASAIO Tram. 37(3) M411-13. 

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