• Food Science and Biotechnology
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• 제15권3호
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• pp.441-446
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• 2006

The biological effects of heating and chemical treatment on castor meal were investigated in order to develop a procedure to inactivate its antigenic activity in a way that is suitable for industrial applications. A 1% solution of purified castor bean allergen (CB-1A) was heat-treated with or without exposure to NaOH and NaOCI (250 ppm each). CB-1A exhibited extreme stability when heat-treated alone. In the presence of NaOH and NaOCl, CB-1A showed a drastic decrease in antigenic activity as the temperature surpassed the critical level of $70^{\circ}C$. The gradual disappearance of disc gel electrophoresis bands presumably responsible for the allergenicity of CB-1A, along with the significant losses of the amino acids phenylalanine, methionine, arginine, histidine, and cysteine correlated with the loss of CB-1A activity. CB-1A showed a single symmetrical band in SDS acrylamide gel electrophoresis with an estimated molecular weight of 6,000 daltons. The chemical and heat treatments reduced the disulfide bond content of CB-1A by 9.1% with a coincident increase in sulfhydryl bonds.

• Journal of Ginseng Research
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• 제30권4호
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• pp.199-205
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• 2006

주기적인 고온환경 부가와 백삼 및 홍삼 추출물의 투여가 흰쥐의 체중, 식이섭취량, 혈액성분, 장기중량 및 간의 지질과 산화에 미치는 영향을 살펴보았다. 흰쥐를 이용한 동물모델 실험결과, 매일 $38^{\circ}C$에서 5시간씩 7일간 고온환경을 부가한 경우 주당 평균체중 증가률이 감소하는 현상이 관찰되었으나 뚜렷한 식이섭취량 변화는 없었다. 반면 고온환경 부가전후에 백삼과 홍삼 추출물을 투여한 경우에는 고온환경 부가에 따른 평균 체중증가률 감소가 억제되었다. 고온환경 부가에 의한 혈액성분 변화를 살펴본 결과에서는 적혈구수와 혈색소량은 큰 차이를 나타내지 않았으나 백혈구수는 다소 증가하는 경향을 나타내었으며 인삼 추출물 투여는 백혈구수 증가도 억제하는 효과를 나타내었다. 고온환경 부가에 따라 장기중 간장의 중량비가 감소하였고 간의 MDA 함량이 크게 증가하였다. 인삼 추출물 투여시에 고온환경부가에 따른 간의 중량감소 및 MDA 함량 증가 등의 변화도 억제되는 효과가 있었다. 특히 간의 중량변화 및 간의 지질과산화 억제효과에 있어서는 백삼보다 홍삼 추출물의 효과가 다소 우수하였으며 통계학적으로 유의적인 수준은 아니었다. 향후 인삼중의 유효성분 구명이나 관련 물질들의 활성 변화에 대한 연구가 필요할 것으로 판단되지만 고온 등 급격한 주위환경가 변화에 대한 인삼의 생체항상성 유지효과를 일부 증명할 수 있는 결과인 것으로 판단되었다.

• Fisheries and Aquatic Sciences
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• 제2권1호
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• pp.85-92
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• 1999

We examined the expression patterns of heat shock proteins in primary cultured hepatocytes from flounder (Paralichthys olivaceus) exposed to heat shock. The expression of hsp90, hsp70, hsp40, hsp30, and hsp27 was induced and major polypeptides were hsp70, hsp30 and hsp27. Northern blot analysis showed that expression of hsp70 was inhibited by transcriptional inhibitor actinomycin D, suggesting that expression of hsp70 gene is regulated at the transcriptional level. Prolonged exposure of cells to an elevated incubation temperature $(30^{\circ}C)$ induced the transient synthesis of hsp90, hsp70, hsp40, and hsp30 whereas maintenance of cells at a slightly higher incubation temperature $(32^{\circ}C)$ induced the continuous syntheses of these hsps. When cells were incubated at a higher temperatures $(35^{\circ}C\;or\;37^{\circ}C)$, the synthesis of hsps was almost similar to that of hsps in cells exposed to 32't except for the induction of hsp27 synthesis. These results that temperature and incubation time for optimum expression of each hsp during prolonged heat shock are different.

• 열처리공학회지
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• 제14권2호
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• pp.110-117
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• 2001

Artificial aging was performed to simulate the microstructural degradation in 2.25CrMo steel arising from long time exposure at $540^{\circ}C$. It was found that the carbides became coarser and spheroidized as aging time increased. An attempt was made to evaluate the microstructural degradation in artificially aging heat treated 2.25CrMo steel by the ultrasonic attenuation and velocity measurements. Ultrasonic velocity was found essentially insensitive to the microstructural changes resulting from aging heat treatment. However, the ultrasonic attenuation was observed to increase with increasing aging time. Also, it was noticed that the change of ultrasonic attenuation with aging time was more sensitive at high frequency regions.

• Asian-Australasian Journal of Animal Sciences
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• 제13권5호
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• pp.694-697
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• 2000

Laying hens kept in different light and dark periods of the day at high ambient temperature of maximum $35^{\circ}C$ were challenged to $38.5{\pm}0.5^{\circ}C$ acute heat 3 hours daily for 7 consecutive days. They were found to have a significant (p<0.01) acclimatization response (rectal temperature) to heat stress during the dark period compared to those exposed to the same temperature during the light period. The blood pH was not significantly different. The partial pressure of carbon dioxide ($PCO_2$) was significantly high (p<0.01) except in day 4. Similarly the blood bicarbonate ($HCO_3$) concentration was significantly high (p<0.05) except day three and day four. Acute heat exposure in the first day increased the body temperature in both groups (Light and Dark) reaching $44^{\circ}C$, followed by gradual reduction in body temperature. The dark treated birds showed rapid reduction in body temperature ($42.88^{\circ}C$) and adaptation to high temperature during days 2-4 but that this was lost to some extent in days 6-8. However this was not obvious in the light treated birds. It is concluded that darkness reduce hyperthermia and enhance acclimatization responses during acute heat stress.

• 열처리공학회지
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• 제23권2호
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• pp.83-89
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• 2010

Diamond-like carbon (DLC) coating was studied to be a good tribological problem-solver due to its low friction characteristics and high hardness. However, generally hydrogenated DLC film has shown a weak thermal stability above $300^{\circ}C$. However, the silicon doping DLC process by DC pulse plasma enhanced chemical vapor deposition (PECVD) for the new DLC coating which has a good characterization with thermal stability at high temperature itself has been observed. And we were discussed a process for optimizing silicon content to promote a good thermal stability using various tetramethylsilane (TMS) and methane gas at high-temperature. The chemical compositions of silicon-containing DLC film was analyzed using X-ray photoelectron spectroscopy (XPS) before and after heat treatment. Raman spectrum analysis showed the changed structure on the surface after the high-temperature exposure testing. In particular, the hardness of silicon-containing DLC film showed different values before and after the annealing treatment.

• Safety and Health at Work
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• 제11권1호
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• pp.1-9
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• 2020

Background: As the impact of climate change intensifies, exposure to heat stress will grow, leading to a loss of work capacity for vulnerable occupations and affecting individual labor decisions. This study estimates the future work capacity under the Representative Concentration Pathways 8.5 scenario and discusses its regional impacts on the occupational structure in the Republic of Korea. Methods: The data utilized for this study constitute the local wet bulb globe temperature from the Korea Meteorological Administration and information from the Korean Working Condition Survey from the Occupational Safety and Health Research Institute of Korea. Using these data, we classify the occupations vulnerable to heat stress and estimate future changes in work capacity at the local scale, considering the occupational structure. We then identify the spatial cluster of diminishing work capacity using exploratory spatial data analysis. Results: Our findings indicate that 52 occupations are at risk of heat stress, including machine operators and elementary laborers working in the construction, welding, metal, and mining industries. Moreover, spatial clusters with diminished work capacity appear in southwest Korea. Conclusion: Although previous studies investigated the work capacity associated with heat stress in terms of climatic impact, this study quantifies the local impacts due to the global risk of climate change. The results suggest the need for mainstreaming an adaptation policy related to work capacity in regional development strategies.

• 한국군사과학기술학회지
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• 제17권2호
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• pp.197-203
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• 2014

In this paper, the effect of unsteady radiation on the horizontal fin of an external fuel tank by flame of a flying flare was analysed to see the temperature increase of the fin and the thermal impact on the fin. Radiation between two surfaces was calculated using the concept of radiation resistance of surface and space including radiation, irradiation and shape factor for two flying trajectories of a flare, maximum temperature of 2200 K, emissivity of 0.95, flying velocity of 30 m/s, and thermal surface area of $0.01m^2$. The result shows that the temperature increase of the fin is 0.236 K, and the thermal effect on the fin is ignorable. And it was found that temperature is increased a little because small amount of heat energy can be radiated due to the short exposure time to the heat source.

• 한국콘텐츠학회논문지
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• 제16권8호
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• pp.419-426
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• 2016

본 연구는 PET-MRI를 다루는 방사선 작업 종사자들의 효과적인 피폭관리와 경과시간(24시간, 1주, 2주, 3주, 4주) 및 자기장에 따른 개인피폭선량계의 변화를 분석하고자 하였다. 그룹화된 TLD에 열처리 수행 및 방사선을 조사하여 각기 다른 노출 환경에 보관한 후 실험이 종료되면 판독을 수행하여 글로우 곡선 및 피폭 방사선량의 변화 추이를 관찰하였다. 그 결과, 24시간 경과한 TLD 그룹에서 글로우 곡선 및 방사선량의 차이가 있는 것으로 확인되었다. 이는 자기장 노출로 인한 변화인 것으로 해석할 수 있다. 또한 자기장에 노출되지 않은 TLD 그룹의 평균 피폭 방사선량은 15.41 mSv로 나타났으며, 자기장에 노출된 TLD 그룹의 평균 피폭 방사선량은 14.83 mSv로 나머지 그룹보다 가장 크게 감소(3.80%)하는 경향을 나타냈다. PET-MRI실에서 근무하는 방사선 작업 종사자가 개인피폭선량계로 TLD를 사용하는 경우, 정기 판독주기에 맞게 TLD 판독 시 자기장 노출로 인한 실제 피폭 방사선량과의 차이는 크게 없을 것으로 판단되어지나 정기 판독이 아닌 중간 판독을 수행하였을 경우, 실제 피폭 방사선량보다 낮은 피폭선량 값을 나타낼 것이다.

• 한국동물생명공학회지
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• 제34권3호
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• pp.240-246
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• 2019

The aim of this study was to investigate effect of heat stress on expression levels of plasminogen activators (PAs) related mRNAs and proteins, and changes of PAs activity in porcine endometrial explants. The endometrial explants (200 ± 50 mg) were isolated from middle part of uterine horn at follicular phase (Day 19-21) and were pre-incubated in serum-free culture medium at 38.5℃ in 5% CO₂ for 18 h. Then, the tissues were transferred into fresh medium and were cultured at different temperature (38.5, 39.5, 40.5 or 41.5℃) for 24 h. The expression level of urokinase-type PA (uPA), type-1 PA inhibitor (PAI-1), type-2 PAI (PAI-2), and heat shock protein-90 (HSP-90) mRNA were analysis by reverse-transcription PCR and proteins were measured by western blotting. The supernatant were used for measurement of PAs activity. In results, mRNA and protein levels of HSP-90 was higher in 41.5℃ treatment groups than other treatment groups (p < 0.05). The expression of uPA, PAI-1, and PAI-2 mRNA were slightly increased by heat stress, however, there were no significant difference. Heat stress condition suppressed expression of active uPA and PAI-2 proteins (p < 0.05), whereas PAI-1 protein was increased (p < 0.01). Although PAI-1 protein was increased and active uPA was decreased, PAs activity was greatly enhanced by exposure of heat stress (p < 0.05). These results suggest that heat stress condition could change intrauterine microenvironment through regulation of PAs activity and other factors regarding with activation of PAs might be regulate by heat stress. Therefore, more studies regarding with regulatory mechanism of PAs activation are needed.