X-Message-Number: 21110
Date: Mon, 10 Feb 2003 07:33:50 -0500
From: Thomas Donaldson <>
Subject: CryoNet #21092 - #21100

For Mr. Kluytmans:

In my final (?) message on these questions I point out that living
systems presently provided the ONLY WORKING EXAMPLE we have of 
complete nanosystems. They should be regarded not with indifference
but as examples of the successes and problems for nanosize design.

I am surprized that you haven't even looked up in any biochemistry
book the kind of bonds which tie enzymes or other living nanomachines
together. I recommend Lehninger, BIOCHEMISTRY. Your arguments, good
or bad, would have been stronger if you had done so.

When you speak about nanotech systems designed for a particular 
purpose I immediately thought of enzymes. Most enzymes aren't
designed to do one particular reaction under one specific set of
circumstances. It is that which makes them more complex than a 
chemical with only one response and one function. Usually enzymes
respond differently depending on their milieu. And enzymes really
do constitute nanomachines, with the right size and consitution.
Cells are much larger and are "devices" composed of nanomachines,
so that their behavior cannot be equated with that of nanomachines.

As for red blood cells, they are more than bags of hemoglobin. They
also act to control blood viscosity, convert CO2 to bicarbonate,
and have their own metabolic system to do these functions. Their
flat shape gives a much larger surface for gas to diffuse in and
out of them. They also cause turbulence in the blood stream, which
helps them diffuse out oxygen and intake CO2. No, they have no
nucleus and are created in our marrow from other cells (do Freitas's
versions self-reproduce? How are they made?). 

If your nanomachines perform only one function, then you will have
to have many more to do the tasks of an enzyme. I would say the
same for devices which transport oxygen and remove CO2. And don't
come back at me saying that the other functions of red blood cells
would no longer be needed: unless you give me the complete 
metabolism of the entire system you want to build with your 
diamandoid nanosystems then you haven't established that even 
Freitas's "blood cells" would really work when tried as a 
substitute... or in a complete system.

More later.

            Best wishes and long long life for all,

                  Thomas Donaldson

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