Secondary interaction hypothesis

What could cause this disagreement Is the whole short-circuiting hypothesis erroneous The answer is that because of the mixing of two such different waters, it is possible that secondary interactions took place, affecting some of the dissolved ions. An example for such secondary reactions in a disposed slaughterhouse effluent is discussed in section 16.3.15. 

The establishment of plant integrated defenses involves the preferential evolutionary retention and production of those SCs exerting synergistic toxic effects and is possible only if a diversification of secondary metabolism in a given plant has previously occurred. This preliminary diversification of secondary metabolism could be mediated via the classical reciprocal co-evolutionary interactions between a host plant and its major pests, as predicted by the chemical arms race model (Beren-baum and Zangerl, 1996). The PICD hypothesis is consequently not an exclusive evolutionary hypothesis because it is compatible with and dependent on other evolutionary processes. The contribution of the PICD hypothesis is to provide both a functional explanation for the diversity of SCs within plants (Romeo et al, 1996) and a reconciliation between different evolutionary models. 

These results suggest that in the pentitols and hexitols, at least, the intermolecular H-bonds have only a secondary influence on the shape of the molecules in the solid state. The observed conformations in the solid state can be rationalized (16) in terms of the intramolecular interactions between hydroxyls which are believed to involve energies of the order of several kilocalories (27) (the interpretation of the NMR spectra of acetylated acyclic sugar derivatives in solution is based on the same type of hypothesis (29)). 

Quantum mechanis (QM) calculations showed that the interaction energy between strontium and amide carbonyl groups increased in the expected sequence primary < secondary < tertiary amides, but could not explain the difference of complexation between (CA1) and (CA2), in particular in chloroform.129 Another hypothesis based on the loss of internal H-bonds with the NH2 protons was also rejected. MD simulations of Sr(Pic)2 complexes of (CA1) and (CA2) for 1 ns at the water/chloroform... 

Nevertheless, the RNA World hypothesis would seem to answer most of the questions raised above how can an essentially linear molecule be autocatalytic, how can it synthesize proteins, and how can it replicate Autocatalysis can occur because RNA can adopt a wide range of secondary and tertiary structures that position RNA monomers into a preorganized sequence and link them together, it can apply the same flexibility to bind other small molecules and catalyse their polymerization, and it could form weakly interacting sense and antisense duplexes. The main problem is... 

Abstract Understanding the origin of chirality in nature has been an active area of research since the time of Pasteur. In this chapter we examine one possible route by which this asymmetry could have arisen, namely chiral-specific chemistry induced by spin-polarized electrons. The various sources of spin-polarized electrons (parity violation, photoemission, and secondary processes) are discussed. Experiments aimed at exploring these interactions are reviewed starting with those based on the Vester-Ulbricht hypothesis through recent studies of spin polarized secondary electrons from a magnetic substrate. We will conclude with a discussion of possible new avenues of research that could impact this area. 

Ghosh etal. also used CD spectroscopy to assess the association affinities of peptide coils in the absence and presence of bound Hg + or Cd +. These authors constmcted a family of peptides having secondary stmctures that bind metal ions in a trigonal thiolate coordination environment, even metal ions like Hg + and Cd + that prefer tetrahedral coordination geometries. Their results indicate increased stability of coUed-coU peptide structures upon addition and binding of the metal ions, and support the hypothesis that favorable tertiary interactions within the protein systems allow for stabilizing the non-preferred coordination geometry of the bound metal ions. 

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