Quasi-living process

The synthesis of A2B miktoarm star polymers has been discussed and exemplified using PIB as a component. The synthesis involves a quasi living cationic polymerization of isobutylene from a monofunctional cationic initiator. This initiator also contains a blocked hydroxyl group. Eventually, the blocked hydroxyl group of the initiator is deblocked, and functionalized with a branching agent. This activated reagent is then used for an atom transfer radical polymerization process of /erf-butyl acrylate (18). 

To summarize, thisprovides one vision of a crucial bridge between the physicists claim of a fine-tuned universe (one predisposed to the production of water, carbon, and nitrogen) and the reality of life on earth. The existence of stable nanotube structures demonstrates how biochemical molecular fine-tuning could give rise to complex entities, presumably through a process of prebiotic molecular selection applied to primitive, quasi-living autocatalytic networks. 

The production of long-lived neutron-rich SH nuclei in collisions of transuranium ions seems to be quite possible due to a large mass and charge rearrangement in the "inverse quasi-fission" process caused by the Z = 82 and N = 126 nuclear shells. Radiochemical identification of isotopes, produced in the U -f Cm... 

Since the metal alkyl is only involved in initiation of chain growth while subsequent propagation and chain transfer (usually involving chain transfer to monomer via hydride abstraction ) are usually very rapid, it is generally not possible to determine the fate of the metal alkyl in such polymerizations. End-group analyses provide evidence for a cationic propagation and chain-transfer mechanism, but the initiator moiety is not detected unless the process is at least quasi-living under the conditions studied. 

These properties are likely to have an important influence on the behavior of intact biochemical systems, e.g., within the living cell, enzymes do not function in dilute homogeneous conditions isolated from one another. The postulates of the Michaelis-Menten formalism are violated in these processes and other formalisms must be considered for the analysis of kinetics in situ. The intracellular environment is very heterogeneous indeed. Many enzymes are now known to be localized within 2-dimensional membranes or quasi 1-dimensional channels, and studies of enzyme organization in situ [26] have shown that essentially all enzymes are found in highly organized states. The mechanisms are more complex, but they are still composed of elementary steps governed by fractal kinetics. 

Finally, reassociation of the broken oligomers occurs with time constants between 9 ps (dimers) and 14 ps (trimers) to a new thermal quasi-equilibrium (level 4) with lifetimes in the nanosecond region. The system does not return to the initial state (0) as a direct consequence of the deposited energy of the excitation process. The resulting temperature increase of the sample is small but produces measurable effects and is estimated from the long-lived amplitude of the signal transients to be below 1 K. 

Resonance phenomena have been shown to play a significant role in many electron collision and photoionization problems. The long lived character of these quasi-stationary states enables them to influence other dynamic processes such as vibrational excitation, dissociative attachment and dissociative recombination. We have shown it is possible to develop ab initio techniques to calculate the resonant wavefunctions, cross sections and dipole matrix elements required to characterize these processes. Our approach, which is firmly rooted in the R-matrix concept, reduces the scattering problem to a matrix problem. By suitable inversion or diagonalization we extract the required resonance parameters. 

The quasi-steady hypothesis is used when short-lived intermediates are formed as part of a relatively slow overall reaction. The short-lived molecules are hypothesized to achieve an approximate steady state in which they are created at nearly the same rate that they are consumed. Their concentration in this quasi-steady state is necessarily small. A typical use of the quasi-steady hypothesis is in chain reactions propagated by free radicals. Free radicals are molecules or atoms having an unpaired electron. Many common organic reactions such as thermal cracking and vinyl polymerization occur by free-radical processes. There are three steps to a typical free-radical reaction initiation, propagation, and termination. 

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