• Asian Pacific Journal of Cancer Prevention
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• v.15 no.12
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• pp.5043-5047
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• 2014

Nowadays increasing effectiveness in cancer therapy and investigation of formation of new strategies that enhance antiproliferative activity against target organs has become a subject of interest. Although the molecular mechanisms of apoptosis can not be fully explained, it is known that cell suicide program existing in their memory genetically is activated by pathophysiological conditions and events such as oxidative stress. Low pressure (hypobaric) conditions that create hypoxia promote apoptosis by inhibiting cell cycling. In this study, determination of the effects of fractional hypobaric applications at different times on HeLa cells at cellular and molecular levels were targeted. Experiments were carried out under hypobaric conditions (35.2 kPa) in a specially designed hypobaric cabin including 2% $O_2$ and 98% N. Application of fractional hypobaric conditions was repeated two times for 3 hours with an interval of 24 hours. At the end of the implementation period cells were allowed to incubate for 24 hours for activation of repair mechanisms. Cell kinetic parameters such as growth rate (MTT) and apoptotic index were used in determination of the effect of hypobaric conditions on HeLa cells. Also in our study expression levels of the Bcl-2 gene family that have regulatory roles in apoptosis were determined by the RT-PCR technique to evaluate molecular mechanisms. The results showed that antiproliferative effect of hypobaric conditions on HeLa cells started three hours from the time of application and increased depending on the period of exposure. While there was a significant decrease in growth rate values, there was a significant increase in apoptotic index values (p<0.01). Also molecular studies showed that hypobaric conditions caused a significant increase in expression level of proapoptotic gene Bax and significant decrease in antiapoptotic Bfl-1. Consequently fractional application of hypobaric conditions on HeLa cell cultures increased both antiproliferative and apoptotic effects and these effects were triggered by the Bax gene.

• KOREAN JOURNAL OF PACKAGING SCIENCE & TECHNOLOGY
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• v.26 no.2
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• pp.53-60
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• 2020

A concept of household container to create and keep the modified atmosphere (MA) beneficial for fresh produce mix was devised and tested under typical chilled storage conditions of 3℃. The container system containing mixed products is initialized by applying weak hypobaric condition (0.9 atm) and subsequently injecting CO₂ gas at an appropriate low level (0.03 atm). The passive atmosphere modification by produce respiration is then induced to reach a target until gas diffusion tube of proper dimension starts to open. The design was made to attain quasi-steady state mass balance of O₂, CO₂ and N₂ to maintain the desired MA through the storage. Interrupted opening for taking out or placing some products was to reinitialize the loop of control logic. The developed concept was tested by the container which held commodities of spinach, pak choi, oyster mushroom, peeled onion, strawberry and cut carrot. The target optimum MA of 11% O₂ and 10% CO₂ (0.11 and 0.10 atm, respectively) was set to avoid injurious range of O₂ and CO₂ concentrations for any commodities. The developed container system could work to reach and maintain beneficial MA of 0.10-0.12 atm O₂ and 0.07-0.10 atm CO₂ close to the target during the storage contributing to quality retention of products measured in weight loss, chlorophyll content of spinach, ascorbic acid content of pak choi, color of onion, texture of oyster mushroom, bacterial count of strawberry and carotenoids of carrot. The container system shows potential to improve current preservation practice of fresh produce mix on consumers' level.

• Journal of the Korean Society for Aviation and Aeronautics
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• v.20 no.2
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• pp.58-63
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• 2012

An altitude chamber, also known as a hypobaric chamber, is a device used during aerospace or high terrestrial altitude research or training to simulate the effects of high altitude on the human body. Although data from altitude chamber researches using experimental animals have been accumulated, studies in the humans exposed to hypobaric conditions are seldomly reported. Despite the importance of altitude chamber flight training in the field of aviation physiology, the hematological analysis of post-flight physiological changes has rarely been performed. The aims of the present study were to investigate the alterations in blood components during altitude chamber flight and to determine whether the differences between pre- and post-flight values are significant. Sixty experienced pilots in the Republic of Korea Air Force were enrolled in the altitude chamber flight training. Venous blood samples were obtained before and immediately after the flight. Compared with the pre-flight values($6.32{\times}10^3/mm^3$, $5.02{\times}10^6/mm^3$, 15.61 g/dL, respectively), white blood cell count, red blood cell count and hemoglobin level were significantly increased after the flight($6.77{\times}10^3/mm^3$, $5.44{\times}10^6/mm^3$, 16.26 g/dL; p=0.006, p=0.012, p<0.001, respectively). These alterations may be attributable to the exposure to hypobaric hypoxia, 100% oxygen supply for denitrogenation, considerable rise and fall in altitude and psychophysical stress due to these factors. In further studies, experimental groups and methods should be individualized to ensure objectivity and diversification. In addition, multiple time-frame analyses regarding the changing pattern of each blood component are also required to elucidate the physiological process for adapting to the high terrestrial altitude exposure.