Stress, and
stress response, are complex multi-level phenomena with internal as well as
external components but for our purposes we can say that any configurational
shift or change imposed on matter is the result of a stress, and that change
or adjustment is its response. Stress response adjustment usually occurs in
a hierarchical sequence or cascade, unless the stress is very mild and fleeting.
Response cascades unfold in a time sequence, the initial protective nonspecific
response being a rapid one of flight or when possible, erection of an impervious
shield. This is then followed by a more leisurely specific sensing and analysis
of the stress, allowing its effects to be absorbed and a corresponding configurational
adjustment to be made. The stress is thereby integrated into the particle’s
structural memory. At that point, if the stress is disturbing enough and if
the stressed particle can muster a requisite amount of energy, it can broadcast
a message back in a directed reaction utilizing the data about the stressor
it has just absorbed. This can alter the stressor so as to either render it
less disturbing or neutralize it by forcing it to partake in a state of equilibrium.
Further levels of response could see the stressor absorbed in its entirety to
become part not only of the stressed particle’s structural memory but also of
its energy/matter resources, a metabolic response. So much for theory – now
how does this relate to the radiogenic micro-environments of the Early Archaean
Earth?
As there is little we can find in the literature relevant to
evolutionary high pressure radiochemistry or radiophysics, we shall be obliged
to proceed largely by analogy. Clearly therefore we are entering the realm of
speculation, and it is particularly from this point on that experimental investigation
is required. The principal feature of confined radiogenic deposits is obviously
the extremely high energy environment which totally dominates and drives all
reactions. Under these circumstances, although molecular bonding may be strongly
encouraged, bonds will tend to be disrupted almost as soon as they are formed,
the perfect paradigm for a stressful environment leading, as in the biological
realm, to rapid evolutionary species divergence. The result will be fierce darwinian
competition, survivors in the short term being molecules which can rapidly attain
stability for reasonable periods while effectively absorbing beta and gamma
radiation. There are in fact two possible adaptive responses dealing with such
an attack: one would be to assume a configuration able to store excess energy,
in other words to tolerate considerable instability, without disintegrating.
Another method would be to adopt a structure which rapidly ejects surplus energy
in a controlled and directed action, without suffering damage or alteration
in the process. The ideal structure would combine both responses, as in a catalytic
reaction. An interesting, perhaps essential, characteristic of such existing
structures is that they preserve their integrity by constantly metabolising
energetic particles, maintaining what one could term a state of controlled instability,
a more appropriate term might be dynamic stability, which is arguably the defining
state characterizing biological systems. Molecules of this type have been synthesized
for industrial purposes and are therefore convenient in order to draw comparisons
with natural analogs.
Industrial application of such structures in recent years has
focused on design and production of organic electro-optic (EO) materials and
devices based on chromophores with a large dipole moment. Organic EO chromophores
are dipolar charge-transfer (transduction)
molecules consisting of an electron donor, an electron acceptor, and a pi-electron
bridge providing communication between the two moieties but more significantly
also providing a variable energy storage structure. These molecules are of interest
to science because they act as antennae, absorbing photons of specific wavelengths
which can be precisely selected by effecting appropriate structural adjustments.
This means that precise amounts of energy can be introduced simply by irradiation
and stored, transported or channelled for delivery in the required form to a
designated location. Examples of such uses are numerous and surprisingly diverse,
including memory storage, switching and logic devices, optical fiber communications,
electro-optic circuitry, photoactive polymer films and dyes, bio-sensors and
many others. One of the most remarkable features of this effort to develop efficient
synthetic chromophores is the consistent emergence of the same small number
of almost identical structures in the various labs around the world and their
striking resemblance to forms found in nature. Among the chromophores with the
greatest polarizability and absorption
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