"The larger cervical vertebrae weigh 250 pounds," said Phillip Fraley, the supervising assistant in charge of rebuilding specimens.
Beebe's observations were relayed up the phone line to be recorded by Gloria Hollister, his chief technical associate who was also in charge of preparing specimens obtained from dredging.
While at Furman he also acted as curator of the natural history museum, taking charge of summer specimen-collecting expeditions, played in the university band, swam for his college and ran the university newspaper.
Arrows indicate the direction of specimen electrons toward the positively charged region marked by a gray-shaded circular area.
In the LV mode, gas molecules surrounding the electron beam for specimen illumination are ionized and electrically neutralize charging of the specimen surface, thus, non conductive specimens can be observed without coating.
Hydrogen charging of some specimens was conducted by cathodic electrolysis using a 0.9 % NaCl aqueous solution at a current density of 10 A m−2 for 6 h at room temperature.
Prior to SEM imaging, bacteria were inactivated by acrolein (Sigma-Aldrich Co., St . Louis MO, USA) treatment and a thin layer (15 nm) of platinum-palladium (Pt-Pd) alloy film was deposited on the sample surfaces to prevent charging of the specimen.
The phenomenon is interpreted as resulting from radiolysis and positive charging of the specimen under electron-beam irradiation.
As the degree of charging of the specimen depends on its electrical conductivity, this parameter is expected to also play a role for the achievable resolution.
Two additional factors that have been attributed to information loss in cryo-EM images are poor detective quantum efficiency (DQE, a frequency-dependent measure for the signal-to-noise performance) of conventional recording devices, and beam-induced movement or charging of the specimen during imaging (Henderson, 1992).
