Single-component molecular composites

Polyimide—Nylon 6 Copolymers Single-Component Molecular Composites... 

Also in relumped form, single-event microkinetics account for all reactions at molecular level [2,3,13], This requires a molecular composition of the lumps considered. The definition of the lumps in hydrocracking is such that thermodynamic equilibrium can be assumed within the lumps. Per carbon number 12 lumps are considered, i.e., normal, mono-, di- and tribranched alkanes, mono-, di-, tri- and tetracycloalkanes and mono-, di-, tri- and tetra-aromatic components. 

Over 300 peptides isolated in our laboratory were studied in one or more tumor or normal cell cultures [39-44]. Part of the results obtained is summarized in Table 2.3. Over 75% of the peptides showed pronounced proliferative or antiproliferative activity in at least one cell type (Fig. 2.3). As a rule, tumor cells are more sensitive to peptide action. Besides the cell type, experimental conditions such as cell density or composition of the culture medium also affected the overall effect. In several cases (13%, Fig. 2.3) even the sign of the effect was peptide concentration dependent. Generally, experiments with cell cultures conform with the view that the main physiological function of cell and tissue peptidomes is control of long term processes and the homeostatic balance (i.e. cell differentiation, proliferation and elimination). The overall effect of peptide pools is achieved by concerted action of total sets of peptides rather than by single components. The molecular mechanisms of peptide action in cells requires concrete study in each individual case and are the subject of current research. 

For multi-component systems it seems intuitive that single-component diffusion and adsorption data would enable one to predict which component would be selectively passed through a membrane. This is only the case where molecular sieving is observed for all other separations where the molecules interact with one another and with the zeolite framework their behavior is determined by these interactions. Differences in membrane properties such as quahty, microstructure, composition and modification can also play a large role in the observed separation characteristics. In many cases, these properties can be manipulated in order to tailor a membrane for a specific apphcation or separation. 

One might expect that vehicle emissions would be related to the composition of the fuel used, and a number of studies have confirmed this (e.g., see Schuet-zle et al., 1994 Siegl et al., 1992 and Kaiser et al., 1991, 1992, 1993). For example, emissions coming from a single-cylinder engine have shown that the mass emissions increase as the molecular weight of a single-component fuel increases and that benzene emissions decrease as the aromatic content of the fuel decreases (Schuetzle et al., 1994). 

Brooks and Cramer [91] extended this work on the single-component mass action model to competitive isotherms. The steric factor (tr) that they introduced to accoimt for this effect depends on the nature of the resin e.g., density of ions), the ionic strength and composition of the solution (which control the molecular structure of the protein), and the nature of the protein and its concentration (most proteins will probably have a larger apparent footprint at high dilution than at high concentration). Thus, the steric factor appears as an additional but empirical... 

The smallest value of x reported thus far in the polymer blend literature is obtained from the SPI(50)/SPB(78) system [system 54]. The x parameter is nearly zero over the entire temperature window. Such a blend is unique because it is predicted to be single phase regardless of composition and temperature. The phase diagram of this system is predicted to be blank, regardless of component molecular weights. 

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