• Analytical Science and Technology
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• v.24 no.3
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• pp.193-199
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• 2011

The purpose of this experiment is to evaluate the stability of products according to the storage methods, the period of use, and the diurnal variations through the short term stability experiment of recombinunt protein A (rProtein A) produced in AP Tech Co. That is, we investigated how long the stability of the products would last, when we used the samples frozen at $-20^{\circ}C$, which is one of the storage conditions of the produced rProtein A and then kept them refrigerated at $4^{\circ}C$. The experiment was conducted for 8 weeks and 6 experiment points were established. The experiment was done by thawing the samples frozen at $-20^{\circ}C$ at room temperature, and then refrigerating them at $4^{\circ}C$. In addition, experiments for endotoxin, bioburden, HPLC purity, and concentration were conducted. As a result of the experiment, 0.5 EU/mg endotoxin was detected both at the beginning and at the 8th week and bioburden was not analyzed. In the case of purity, it showed 99.23~99.90% at 210 nm (RSD% 0.23%) and 100% at 280 nm, which meant the change into other materials didn't happen and there was no material degradation characteristics. Finally, we also found the fact that the concentration stayed stable at 55.15 mg/mL (RSD% 0.55%) both at the beginning and at the end. From the experiment results, we were able to conclude that the stability at the condition to store rProtein A at 4 oC for 8 weeks was procured without producing microorganisms or having material degradation characteristics.

• Economic and Environmental Geology
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• v.53 no.4
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• pp.413-423
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• 2020

Over the wide area, King Sejong Station and the nearby land are uncovered with snow and ice conditions. Therefore, the active layer on the permafrost has been formed to be much thicker than the other Antarctica region. Electrical resistivity survey of Wenner and dipole-dipole arrays was undertaken at a series of time in the freezing season at the King Sejong Station to delineate subsurface structure and to monitor active layer in permafrost terrain. Time-lapse resistivity structures are well in terms of the vegetation distribution, ground surface temperature, and snow depth. Horizontal high resistivity belt(>1826 Ωm) at very shallow depth is thickening with the lapse of time, probably caused by the freezing of the water in the pore spaces with decrease of ground temperature. Subsurface structures for the area of low snow-cover and vegetated zone area are comprised of 0~0.5 m deep high-resistive gravel-rich soil, 0.5~3 m deep low-resistive active layer, and the underlying permafrost. In contrast, the unvegetated area and high snow-buildup is characterized with high resistivities larger than approximately 2000 Ωm due to freezing of the soil throughout the year. Data interpretation and correlation schemes explored in this paper can be applied to confirm the active layer, which is expected to get thinner in additional survey during the thawing season.