Weak interaction critical control

The above result unequivocally demonstrates that the seemingly weak solvation effect can play a decisive role, which controls and even switches the stereochemical outcome of the enantiodifferentiating photoisomerization. Temperature, pressure, and solvation, which function as environmental factors to control the enantiodifferentiation in the excited state, are all entropic in nature. Probably the key is the critical control of the weak interactions involved in the exciplex intermediate, as with the biological and supramolecular interactions in... 

Photochemistry also has drawbacks the excited-state interactions are weak and short-lived and are therefore difficult to control also the detection/observation of transient species and the subsequent elucidation of the reaction mechanism are in general more difficult [17]. Consequently, it has long been believed that the critical and precise control of asymmetric photoreactions is a hard task, and that the optical yields obtained therefrom are low. To overcome this, two strategies have been developed in the evolution of asymmetric photochemistry, or photo-... 

One of the basic principles of controlling the properties of adhesives considered here is inclusion of surface-active substances (surfactants) capable of chemical interaction with the adhesive components and entering into the adhesives composition. Such reactive surface-active (RS) substances differ radically from chemically indifferent surface-active (IS) substances. In the course of polymerization of oligomers containing IS substances there is a decrease of the critical concentration for micelle formation (CCMF) and formation of substanti d quantities of large micelles of surfactant, which results in weak layers on the boundary between the adhesive and substrate and in decrease of the adhesion strength. 

Success in protein voltammetry depends critically upon the electrode and how it is prepared and modified. The current response may stem from protein molecules free in solution and undergoing a reaction upon diffusing to the electrode surface, or it may stem from molecules that are already bound tightly (adsorbed) to the electrode. Quasi-reversible diffusion-controlled electrochemistry has been documented for a wide range of proteins, mostly the smaller variety (molecular mass <15kDa) that function as mobile electron carriers [3], Diffusion-controlled electrochemistry requires that the protein interacts with the electrode in a transient manner, that is, weakly, so that the electrode does not become blocked. Increasingly, however, attention has turned to electrodes that bind protein molecules tightly, so that the sample is studied as a stable monolayer that typically comprises less than a picomole [1]. 

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