Oscillator strength spectra in the region of B 1s and C 1s excitation of three isomeric carborane cage compounds [closo-1,2-orthocarborane, closo-1,7-metacarborane, closo-1,12-paracarborane (C2B10H12)] have been derived from inner-shell electron energy loss spectra (ISEELS) recorded under electric dipole-scattering conditions. Total ion yield spectra recorded at high resolution with synchrotron radiation are also reported. The spectral features are assigned on the basis of comparisons with spectral predictions derived from the results of ab initio and semiempirical (extended Hückel) molecular orbital calculations. The isomeric and core level variations in the discrete core excitations are related to changes in orbital symmetries as well as variations in electron localization in these isomers. The ionization efficiency in the region of the B 1s and C 1s edges is derived.

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A theoretical study of several new classes of polyhedral-based molecules has shown that these species display large calculated nonlinear optical responses. These new classes of molecules are based on charged aromatic subunits connected through polyhedral cluster bridges, such as closo-[1-(C(7)H(6))-12-(C(5)Me(4))C(2)B(10)H(10)]. These compounds show calculated first hyperpolarizabilities (beta) ranging from 6.5 to 8413.9 x 10(-30) cm(5) esu(-1). A basis for understanding the origin of these large responses is proposed based on the two-state model and consideration of the orbital and electronic features of the molecules. In general, the highest occupied molecular orbitals for these species are localized on the aromatic donor rings, such as the cyclopentadienyl system, while the lowest unoccupied molecular orbitals are largely on the aromatic acceptor rings, such as the tropylium system. The electronic properties of these polyhedral-based systems appear to be significantly different from the analogous organic [5.6.7]quinarene system (tropyliumcyclopentadienylbenzene). The organic quinarene appears to behave as a completely electron-delocalized system over all three rings while the polyhedral-based compounds can best be described as consisting of two relatively independent, highly polarized regions.

This paper is the report of a study of 300 patients with symptoms or findings indicative of the presence of inner ear disease who were studied and tested by lipoprotein phenotyping, and an incidence of 42.33 percent was found to have clearly defined hyperlipoproteinemia (HLP) on the basis of the laboratory tests with an additional 8.66 percent whose tests were presumptive enough to permit their classification as being hyperlipoproteinemic. Hyperlipoproteinemia has its greatest clinical significance in that its correlation with coronary artery disease (CAD) makes its early detection and subsequent treatment, at least by dietary control, most important in preventing the excessive mortality from atherosclerosis and its complications. The statistically high incidence of HLP in the 300 patients reported in this paper, who had either or both cochlear and vestibular symptoms, adds further credence to the work, observations, and reports of Rosen, whose epidemiological studies show a high correlation of hearing loss with elevated cholesterol, atherosclerosis, and coronary artery disease in those population groups whose dietary intake of saturated fats is high. Otologists now need to join hands with the internists and pediatricians in seeking an early diagnosis of hyperlipoproteinemia. In so doing, a metabolic abnormality which apparently leads to labyrinthine dysfunction, coronary artery disease, and other related illnesses may be better controlled. May nutritionists also take note, as it is very apparent that what people are eating may not be good for them for, as Lucretius wrote in 55 B.C. in his treatise, “De Rerum Natura,” “One man's meat is another man's poison.”

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