Hildebrand hypothesis

High yield, high selectivity (HY/HS) catalysts, 20 536, 537, 544 Hildebrand-Scatchard hypothesis, 23 97 Hill climbing, 7 400... 

In support of the theory that in brown soln. a complex of solute and solvent is formed, F. Dolezalek 1 having shown that the partial press, of each form of a substance in a soln. is proportional to the molecular proportion of it present in the mixture, P. Wantig found that boiling soln. of iodine in ether, carbon disulphide, carbon tetrachloride, chloroform, and benzene agree with the assumption that even at the b.p. there is a considerable amount of association between iodine and the solvents which form brown soln. With this hypothesis also before them, J. H. Hildebrand and B. L. Glascock measured the depression of the f.p. of certain neutral solvents—bromoform and ethylene dibromide—produce by iodine and certain liquids separately and together. With mixtures which produce violet soln. the total depression of the mixture in the constituents are considered separately or together with mixtures which produce brown soln. the total depression with the mixture is less than the sum of the separate depressions. This is taken as a proof... 

Considerable evidence concerning the central olfactory pathways of insects is available and may be used to draw a reasonable hypothesis as to the organization and physiology (Hansson and Anton, 2000). In these model dipteran and lepidopteran systems, electrical activity in the form of action potentials that arise in response to the signal transduction events initiated by the olfactory stimulus is directed along ORN axons to the AL where synaptic connections are made that mediate signaling to higher centers within the insect CNS (Hildebrand and... 

The molecular weight of a solvent is a standard but underutilized component of the information on properties of solvents. Many solvent properties depend directly on their molecular weights. The hypothesis of Hildebrand-Scratchard states fliat solvent-solute interaction occurs when solvent and polymer segment have similar molecular weights. This is related to the hole theory according to which a solvent occupying a certain volume leaves the same volume free when it is displaced. This free volume should be sufficient to fit the polymer segment which takes over the position formerly occupied by the solvent molecule. 

It has been reported thata-naphthaleneacetic acid (NAA) or indoleacetic acid can induce the expression of acidic LOXs in cultured immature soybean cotyledons [32]. Further studies showed that one of NAA-induced LOXs is LOX-4 (C. Wang and D.F. Hildebrand, unpublished work). LOX-4 is expressed in germinable somatic embryos, but not in non-germinable ones [33]. The fact that exogenous auxin can induce LOX-4 expression in cultured soybean cotyledons ([32], C. Wang and D.F. Hildebrand, unpublished work) supports the hypothesis that auxin may play a role in induction of seedling LOX expression in germinating soybeans. 

Charge transfer spectra of the carbazole polymer with TCNQ were measured in several solvents and compared to the model compound. The results are shown in Table 1. K and e were calculated using the Benesi-Hildebrand equation.is almost independent of whether the material is polymer or model compound, e is higher for the polymer while A max is unchanged. This is difficult to explain at present. One hypothesis is that the polymer may form a DDA complex, which will increase e and may not increase X max or K. 

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