35. The purpose of raising the stage temperature above room
temperature is to prevent condensation when the liquid nitrogen is attached. For instructions on profile programming, refer
to the Linksys32 User Guide. After changing any value in the
temperature profile table, always use the “Enter” key, or alternatively, use the mouse to click in a different table cell; this
ensures that the system controller registers the updated value.
36. Push the fitting in firmly until the valve clicks open. If properly
inserted, it should not be possible to pull the fitting out of the
gas port.
37. Inspect the dewar before adding liquid nitrogen: the dewar
interior must be free of particulates, condensation, frost, or ice,
as these can cause the siphon inlet filter to clog. If there is frost
or significant condensation on the interior surfaces of the
dewar, it may be necessary to warm up the dewar using a
handheld blow-dryer.
38. Ensure that the brass intake filter at the end of the dewar lid
siphon tubing is at or above room temperature before submerging it in the liquid nitrogen; if the metal is cold (e.g., if the
dewar was recently in use), then condensation may form, causing the filter to be blocked by ice when immersed into the
liquid nitrogen. Do not close the lid too quickly after lowering
the siphon into the liquid, as the boil-off may cause pressure
buildup that can result in ejection of liquid nitrogen through
the capillary tube. Whenever handling the lid, take care not to
damage the black siphon capillary tubing; for example, when
setting the lid down, always turn it upside-down (interior
side up).
39. It is possible to directly modify the hold temperature of the
currently active ramp (which is highlighted in blue in the
temperature profile table). Simply revise temperature value in
the “Limit” column, and then press “Enter.”
40. The sample loading temperature is the temperature at which
the sample will be held before the freezing process starts. This
temperature should be above room temperature (to prevent
condensation) and often corresponds to the normal incubation
temperature for the cell type under study (e.g., 37
C for
mammalian cells).
41. The seeding temperature is the temperature at which extracellular ice crystallization will be induced, at the start of the cell
freezing experiment. This temperature should be near (typically within Æ1
C) the melting point of the solution. If the
seeding temperature is too high, the time of contact required
between the sample and the seeding cold-spot to achieve ice
formation may become very long, resulting in (uncontrolled)
cooling of large parts of the sample. Furthermore, if the
High-Speed Video Cryomicroscopy
251
temperature is to prevent condensation when the liquid nitrogen is attached. For instructions on profile programming, refer
to the Linksys32 User Guide. After changing any value in the
temperature profile table, always use the “Enter” key, or alternatively, use the mouse to click in a different table cell; this
ensures that the system controller registers the updated value.
36. Push the fitting in firmly until the valve clicks open. If properly
inserted, it should not be possible to pull the fitting out of the
gas port.
37. Inspect the dewar before adding liquid nitrogen: the dewar
interior must be free of particulates, condensation, frost, or ice,
as these can cause the siphon inlet filter to clog. If there is frost
or significant condensation on the interior surfaces of the
dewar, it may be necessary to warm up the dewar using a
handheld blow-dryer.
38. Ensure that the brass intake filter at the end of the dewar lid
siphon tubing is at or above room temperature before submerging it in the liquid nitrogen; if the metal is cold (e.g., if the
dewar was recently in use), then condensation may form, causing the filter to be blocked by ice when immersed into the
liquid nitrogen. Do not close the lid too quickly after lowering
the siphon into the liquid, as the boil-off may cause pressure
buildup that can result in ejection of liquid nitrogen through
the capillary tube. Whenever handling the lid, take care not to
damage the black siphon capillary tubing; for example, when
setting the lid down, always turn it upside-down (interior
side up).
39. It is possible to directly modify the hold temperature of the
currently active ramp (which is highlighted in blue in the
temperature profile table). Simply revise temperature value in
the “Limit” column, and then press “Enter.”
40. The sample loading temperature is the temperature at which
the sample will be held before the freezing process starts. This
temperature should be above room temperature (to prevent
condensation) and often corresponds to the normal incubation
temperature for the cell type under study (e.g., 37
C for
mammalian cells).
41. The seeding temperature is the temperature at which extracellular ice crystallization will be induced, at the start of the cell
freezing experiment. This temperature should be near (typically within Æ1
C) the melting point of the solution. If the
seeding temperature is too high, the time of contact required
between the sample and the seeding cold-spot to achieve ice
formation may become very long, resulting in (uncontrolled)
cooling of large parts of the sample. Furthermore, if the
High-Speed Video Cryomicroscopy
251