Fernandez-Moran (refs. [ref.163]-[ref.165]), at the University of
Chicago, has devised a new multielectrode electrostatic lens which he
has incorporated into an electron microscope. This necessitated the
development of a novel high-voltage power source and voltage regulator
of extreme stability and accuracy. Some promising work has now been done
on superconducting lenses. In a series of experiments with a simple
electron microscope without pole pieces, using high-field
superconducting niobium-zirconium solenoid lenses in an open air core,
liquid helium Dewar, electron microscopic images of test specimens have
been recorded while operating at 32 200 gauss in a persistent current
mode, with regulated accelerating potentials of 4 to 8 kilovolts. These
preliminary experiments have demonstrated the exceptional stability of
the images (both short term and long term) over a period of 4 to 8 hours
and the relatively high quality of the images.
Progress has been made on the viscosimeter for high intrinsic
viscosities. This is now working, and the viscosity of DNA preparations
has been measured. It is hoped to use the viscosimeter to study the
variation in DNA viscosity as a function of the cell cycle.
An instrument is under development by Wald at the University of
Pittsburgh to automatically analyze cytogenetic material and, thus,
extend cytogenetic methodology both for research and as a biological
monitoring procedure, using automatic electronic scanning and computer
analysis of chromosomes. Chromosomal aberrations can thus be monitored
under unusual and abnormal conditions such as weightlessness and
radiation, since chromosomes are very sensitive to stress situations. In
this device a sample will be prepared and automatically inserted under a
microscope lens. The device will then scan, identify, and photograph on
35-mm film a predetermined number of mitotic cells and process the film.
The data will be recorded under the direct control of a digital
computer. The computer will perform a detailed quantitative analysis of
the pictorial data.
Significant effort has been expended in the development of
instrumentation for measuring and recording electrophysiological
information. One such instrument, developed by the Franklin Institute,
Philadelphia, Pa., is a temperature-sensing microprobe. This microprobe
is an implantable and remote broadcasting instrument. These developments
are associated, in part, with training programs so that competent
individuals may be trained not only in electronics but also in the
biological uses of the devices they construct.
A project of interest, conducted at the Stanford Research Institute, is
the investigation of the uses of an extremely sensitive method for
measuring magnetic susceptibility having the possibility of detecting
macroscopic quantum effects in macromolecules of biological interest.
Good progress has been made in the first 15 months of a project devoted
to the development and initial use of equipment specifically designed
for this purpose. A new superconducting circuit, together with
superconducting magnetic shields, has been constructed. This apparatus
can measure the magnetic susceptibility of small organic samples at
temperatures between 1° and 300° K in fields up to 40 000 gauss. It can
detect flux changes of 10⁷ gauss-cm², which is equivalent to detecting a
change in specific susceptibility of 1 in 10⁹ in a 100-mg sample under
an applied field of 10 000 gauss.
Several hundred preliminary measurements were made on samples of
coronene. The most reliable of these were in agreement with published
values of the magnetic susceptibility of coronene. Experience during
these measurements led to changes which have resulted in an apparatus
well suited to the measurements on macromolecules. An improved version
of the superconducting circuit now available shows promise of a further
improvement in sensitivity by a factor of more than a thousand
([ref.166]).
Living organisms possess many unique processes and systems which are
complex and poorly understood. The new theoretical approaches, combined
with laboratory studies, are expected to result in advances which will
expand both our scientific and technological horizons.
chapter 6
_Flight Programs_