Pattern of heterogeneity

A large degree of heterogeneity means that it is often not possible to set the tight specifications normally seen with chemical NCEs and test limits may be wide. Therefore, it is important to characterize the pattern of heterogeneity and to demonstrate lot-to-lot consistency of the development batches. 

The form for the pattern of heterogeneity for the solid is assumed to be the same for all components, and this pattern is assumed to take the form... 

Heinze T., Erler U., Nehls 1., Klemm D., Detemunation of the substituent pattern of heterogeneously and homogeneously synthesized carboxymethyl cellulose by using high-performance liquid chromatography, Angew. Makrotnol. Chem., 215, 1994, 93-106. 

Heinze Th, Erler U, Nehls I, Klemm D (1994) Detrmnination of the substitution pattern of heterogeneously and homogenously synthesized earboxymethyl cellulose by using high-performance liquid chromatography. Angew Maknnnol Chem 215 93-106 Hon DNS (1996a) Cellulose and its derivatives. In Dumitriu S (ed) Polysaccharides in medicinal applications. Marcel Dekker, New York... 

While following the general pattern of heterogeneous chemical reactions, electrode reactions are additionally characterized by being associated with the transfer of electric charge across the interface between two conductive phases. This is why the energetics, hence, the rate of charge transfer from one phase to the other, depends on the electric potential difference between these phases. Thus, in addition to the variables commonly involved in chemical... 

In general, the multiphasic heterogenous nature of the impact grade styrene-based polymers is the root cause of their opaque-turbid nature. In determining the transparency of the blends, size and the size-distribution pattern of the dispersed phase along with the refractive index difference between the continuous and the dispersed phases are two very important criterion [133]. 

Computational chemistry has reached a level in which adsorption, dissociation and formation of new bonds can be described with reasonable accuracy. Consequently trends in reactivity patterns can be very well predicted nowadays. Such theoretical studies have had a strong impact in the field of heterogeneous catalysis, particularly because many experimental data are available for comparison from surface science studies (e.g. heats of adsorption, adsorption geometries, vibrational frequencies, activation energies of elementary reaction steps) to validate theoretical predictions. 

Lamina IV is composed of heterogeneous sized cells and is less densely packed than lamina III due to the number of nerve axons passing in this layer. At least three types of neurons have been identified in lamina IV, based on different dendritic projection patterns and these include SCT and PSDC cells. Another cell type has been described which has a dendritic pattern similar to SCT and PSDC, but with local axon terminations. Somas of STT cells are also found in lamina IV. 

In the recent past much ejperimental and theoretical effort has been undertaken to understand the microsoopic steps of heterogeneous surface reactions. Ihe main problem oonsists of evaluating the total energy of the reacting coponents (including tiie surface atoms ) as a function of all nuclear coordinates at any reaction time. The solution of this problem is extremely difficult. Detailed studies with model systems, however, can shed same light ipon the various steps of the interaction pattern. 

Lenhert, S., Sun, P., Wang, Y, Fichs, H. and Mirkin, C. A. (2007) Massively parallel dip-pen nanohthography of heterogeneous supported phospholipid multilayer patterns. Small, 3, 71-75. 

Wilson J., Nobrega J., Carroll M. et al. Heterogenous subregional binding patterns of 3H-WIN 35,428 and 3H-GBR 12,935 are differentially regulated by chronic cocaine self-administration. J. Neurosci. 14 2966, 1994. 

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