Treatment-by-center interaction

In a multicenter study, the results from the individual centers should be presented, and tests for treatment-by-center interactions should be performed. 

Kallen A (199 7) Treatment-by-center interaction What is the issue Drug Information Journal 31 ... 

Treatment-by-center interaction. This is the type of inconsistency that may cause an invalidation of the entire study. Here, the relative response to the different study treatments is different across centers. There are two situations that present qualitatively different levels of difficulties ... 

Figure 21.2 Treatment by center interaction quantitative interaction...

For multicenter studies, statistical models should include terms for center (study) effects, and treatment-by-study interaction (two-way models) should be tested and examined. 

Second, consider an experiment in which molecules are deflected by inhomogeneous electric field. According to the conventional description, the deflection is caused by the interaction between the field and the molecules represented by material points with permanent dipole moments. On the other hand, a rigorous quantum-mechanical treatment of this phenomenon calls for the consideration of the coupling between the overall motion of the center-of-mass and the perturbed spectroscopic states [24]. This coupling arises as a consequence of the fact that the total momenta of molecules are not conserved in the course of such an experiment. 

In the above treatment of exchange interactions we have eonsidered the magnetic electrons, i.e., the ones involved in the interaction, as essentially localized on a given magnetic center. Although this is usually a good approximation for systems formed either by identical or by completely... 

In 1950 Isihara proved a geometrical identity for convex bodies and pointed out the fact that the identity is useful for treatment of molecular interactions in uniform gases and liquid solutions. His work was improved and generalized by the present author. - For spherically symmetric molecules the intermolecular potential is a function of the distance between the molecular centers. The above-mentioned generalization was based on the supposition that the intermolecular potential was a function of the shortest distance between convex cores assumed within the molecules. On this supposition a useful expression for the second virial... 

To improve adhesion of binders to fibres, including carbon fibers, methods of surface treatment by cold plasma were developed. In the course of such treatment, the removal of a weak border layer of the fiber proceeds and the contact between the surface and a binder is improved. At the same time, the number of active centers capable of chemical interaction with a binder increases and the wetting becomes better. It may be expected that pol5mierization under plasma action may also serve as a tool adhesion improvement at the phase border. In spite of the existence of many ways of surface treatment of the reinforcement surface, no model of interaction was proposed which is effective in predicting the t5T)e of reinforcement by surface treatment of a given filler-matrix combination. According to Drzal, the major reason for this lack of theoretical developments is in the over-simplification of the composition and nature of the filler-matrix interface. 

Election nuclear dynamics theory is a direct nonadiababc dynamics approach to molecular processes and uses an electi onic basis of atomic orbitals attached to dynamical centers, whose positions and momenta are dynamical variables. Although computationally intensive, this approach is general and has a systematic hierarchy of approximations when applied in an ab initio fashion. It can also be applied with semiempirical treatment of electronic degrees of freedom [4]. It is important to recognize that the reactants in this approach are not forced to follow a certain reaction path but for a given set of initial conditions the entire system evolves in time in a completely dynamical manner dictated by the inteiparbcle interactions. 

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