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PSL in space with
the ESA - 2000
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PSL have recently taken part in further trials of their new Miniature ICCD camera in zero-G conditions aboard an ESA Airbus.

Thirty zero-G sessions were accomplished during the flight, each lasting approximately 30 seconds.

 

The system used for parabolic experiments
is compact and battery-powered.
Each experiment aboard the flight is packaged as it would be on a satellite launch, and runs automatically.
The system is compact and battery-powered.

The PSL experiment, designed with the collaboration of the Phillips University (Marburg), studies the behaviour of osteoblasts in zero-G conditions.
A central controller of cellular activity is the metal ion calcium. It is possible that calcium ion regulation of biochemical activity was one of the first control systems when life started.
Some years ago it was found that, among the hormonal controls of osteoblasts, mechanical feedback was partially regulated by intracellular calcium. Mechanical feedback in bone increases strength when loaded and decreases strength when not loaded — as in osteoporosis — which can affect astronauts.
Keep in mind that there is no direct connection between the calcium that stiffens biological structures such as bone and the metabolic calcium that regulates cell activity.
While considering how bone reacts in space with little mechanical force acting on it, researchers performed space experiments on single cells that suggested that cells can sense the lack of gravity. Many scientists believe that cells can sense the small mechanical forces acting on them, although this is not our view.

Laboratory experiments show that the concentration of calcium in single cells changes in response to small deformations, such as those resulting from running. This discovery led to a proposal to NASA and the European Space Agency (ESA) that the intracellular calcium in osteoblasts in a microgravity environment should be measured.
In parabolic flights, a series of 30 parabolas are flown where microgravity is experienced for about 20 to 24 seconds, preceded and followed during the acceleration and pullout phases by forces of 1.8g. This is similar to the effects of a 3000m roller coaster.
Earlier in 2000, we flew our fourth parabolic experiment. This time the Micro-ICCD camera from Photonic Science, originally made to fit the helmets of air force pilots, was used. The camera is small, lightweight and ultrasensitive, combining high contrast with a resolution in the range of 20 to 40 line pairs per millimetre and a very good signal-to-noise ratio.
The camera functions in two modes: it can be used with manual gain for manned/zero-G experiments, or it can function completely automatically with gain management for rocket-based experiments. The Micro-ICCD also has a gating function for gain control in day and night imaging, as well as for applications-oriented functions. The next zero-G experiments will use gating for time-dependent imaging.
The camera was coupled to a minimal microscope, which uses optics but none of the traditional pieces, such as a stage, of laboratory microscopes. For excitation we used a 470nm light-emitting diode from Nichia of Japan, which delivered sufficient power to excite the Oregon Green dye from Molecular Probes of Leiden, The Netherlands. Although the dye has a maximum absorption at 490nm, this wavelength provided adequate emission. The camera showed very good sensitivity; in fact, we amplified the intensifier gain only to half range.
We were able to show with this system that microgravity did not affect the cells mechanically, nor did it affect the cells' response to fluid shear. By reducing the size and complexity of the experiment, ground-based control experiments can be conducted using clinostats and centrifuges, as well as fly-control centrifuges, which are technically simple, rugged, and require low power.
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