ý.,,: V. ý ýý . - Nottingham eTheses - University of Nottingham

-ý- ----
,. r. __-_-. ___. r.
ýý-
_ __
---
--
--
E
F
G
12345678g 10.11 12
Figure 4.4 HTAP - assay in a 96 well microtitre plate. The low contrast between negative and
positive samples means that analysis for this plate is difficult. However, direct visual analysis can be
more effective at discerning positive from negative, the following were considered positive, A 12, B7,
C4, D3, D6, D10, D12, E5, E8, F3, F5, F6, F10, G4, G8, H7, H10.
of the light box to prevent radiated heat from the light source altering the temperature of
the samples. Visual observations were recorded and a digital photograph was taken of
each plate.
This protocol was used when in the field; however, as previously stated, a dedicated
cold room was not always available and as such the freeze plate apparatus had to be
stored in a 4°C cold room and the metal surface of the plate sealed from the external
environment. A polystyrene ice-box was used to isolate the air space above the cold plate
and the air temperature was recorded using a thermometer. When the internal temperature
had reached -10°C, the microtitre plates were taken from the -70°C
freezer and quickly
placed on the cold-plate. On average, the internal temperature rose only 4°C. After the
plates were placed on the block, the temperature control was set at -6°C and the apparatus
was left for 5 days. Observation and recording of results was carried out in the cold room
by quickly placing the microtitre plate onto a light source. making a rapid visual
assessment of the refraction status of each sample, then taking a photograph using a
119