• Title/Summary/Keyword: Heat exposure

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Suggestion on experimental animal model of the dermatitis with dampness-heat syndrome in the traditional Korean medicine

  • Lim, Dahae;Go, Jihyun;Hong, Sungwei;Kang, Sangwoo;Yoou, Myoung-Schook;Kim, Na-Rae;Nam, Sun-Young
    • CELLMED
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    • v.5 no.1
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    • pp.2.1-2.2
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    • 2015
  • According to the traditional Korean medicine, Dampness-heat (DH)is an abnormal state of the body that results in a pathological accumulation of dampness and heat. DH is caused by overeating fatty, sweet foods or overdrinking alcohol. Exposure to hot and humid atmospheres is another cause of DH. Although many experimental animal model on various diseases related with DH syndrome were established, DH syndrome dermatitis model is not established. Thus, we introduce the experimental animal model of the dermatitis with DH syndrome.

Study on the optimum hot forming temperature and solution heat treatment temperature for the super duplex stainless steel weld (수퍼 이상 스테인리스강 용접부의 최적 열간 성형온도 및 용체화 열처리 온도에 관한 연구)

  • Ji Chun-Ho;Choi Jun-Tae;Kim Dae-Sun
    • Proceedings of the KWS Conference
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    • 2006.05a
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    • pp.137-139
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    • 2006
  • In order to establish the optimum hot forming temperature and solution heat treatment temperature for 25% chromium super duplex stainless steel weld, a commercial 25%Cr-10%Ni-4%Mo weld metal for super duplex stainless steel(UNS S32750) with different solution heat treatment conditions at $1100^{\circ}C,\;1050^{\circ}C,\;1025^{\circ}C\;and\;1000^{\circ}C$ for 1.5 hours has been investigated by means of optical metallography, and estimated mechanical properties. It is found that exposure to elevated temperatures at $1050^{\circ}C,\;1025^{\circ}C\;and\;1000^{\circ}C$ except $1100^{\circ}C$ brings partial decomposition of ferrite to austenite and sigma phase, which deteriorates their properties and heat treatment at $1100^{\circ}C$ shows acceptable mechanical properties.

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Physiological Strains of Asbestos Abatement Work Wearing Protective Clothing in Hot-Humid Environments

  • Tochihara, Yutaka;Ohnaka, Tadakatsu
    • Fashion & Textile Research Journal
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    • v.2 no.5
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    • pp.411-415
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    • 2000
  • To be able to work safely and efficiency, the Threshold Limit Values (TLV) for work in the heat are widely used. Since these TLV are only applicable to workers in regular clothing, TLV should be adjusted when applied to the asbestos removal workers who wear extra impermeable protective clothing. Although abbreviated guidelines for heat stress exposure have been proposed, literature advocating their use in the asbestos removal industry is limited. Therefore, we planed a survey to evaluate the workload of asbestos abatement workers in summer, and an experiment with climatic chambers to evaluate the effects of resting in a cool environment between work periods. From these studies, we got following conclusions. There is a high risk of suffering from heat illness by asbestos abatement work in summer in Japan. It is proposed to create a cool room inside the workplace of asbestos abatement work to reduce thermal stress.

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Changes of Carbide Characteristics and Magnetic Properties in Artificially Aging Heat Treated 2.25CrMo Steel (경년열화 열처리된 2.25CrMo 강에서의 탄화물 특성 및 자기적 성질의 변화)

  • Byeon, Jal Won;Kwun, S.I.
    • Journal of the Korean Society for Heat Treatment
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    • v.14 no.6
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    • pp.323-329
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    • 2001
  • Artificial aging was performed to simulate the microstructural degradation in 2.25CrMo steel arising from long time exposure at $540^{\circ}C$. The carbide morphologies were classified as acicular, pipe and globular type, and the number of carbides per unit area was measured for each type of carbides. The fine acicular carbides were found to diminish drastically in the initial stage of aging. An attempt was made to evaluate the microstructural degradation in artificially aging heat treated 2.25CrMo steel by the magnetic property measurements such as saturation magnetization, coercivity and remanence. The saturation magnetization showed no distinct trend with aging time. However, the coercivity and remanence were observed to decrease rapidly in initial 920 hours of aging time and then decrease slowly afterwards.

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HSP70 and HSC70 gene Expression in Chironomus Tentans (Diptera, Chironomidae) larvae Exposed to Various Environmental Pollutants: Potential Biomarker for Environmental Monitoring

  • Lee Sun Mi;Choi Jin Hee
    • Environmental Mutagens and Carcinogens
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    • v.25 no.1
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    • pp.32-39
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    • 2005
  • In order to identify potential biomarkers of environmental monitoring, we evaluated heat shock genes expressions as effects of various environmental pollutants (nonylphenol, bisphenol-A, 17a­ethynyl estradiol, bis(2-ethylhexyl)phthalate, endosulfan, paraquat dichloride, chloropyriphos, fenitrothion, cadmium chloride, lead nitrate, potassium dichromate, benzo[a]pyrene and carbon tetrachloride) on larvae of aquatic midge Chironomus tentans (Diptera, Chironomidae). Heat shock protein 70 gene expression increased in most of chemicals treated larvae compared to control. The response was rapid and sensitive to low chemical concentrations but not stressor specific. In conjunction with stressor specific biomarkers, heat shock protein 70 gene expression in Chironomus might be developed for assessing exposure to environmental stressors in the fresh water ecosystem. Considering the potential of Chironomus larvae as biomonitoring species, heat shock gene expression has a considerable potential as a sensitive biomarker for environmental monitoring in Chironomus.

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Olive flounder (Paralichthys olivaceus) leukocytes stimulated with poly (I:C) could kill Miamiensis avidus (Ciliophora: Scuticociliatia) only when ciliates were immobilized by antiserum

  • Kang, Yue Jai;Kim, Ki Hong
    • Journal of fish pathology
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    • v.31 no.2
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    • pp.109-113
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    • 2018
  • The purpose of the present study was to determine whether the scuticocidal activity of olive flounder (Paralichthys olivaceus) head-kidney leucocytes can be enhanced by stimulation with polyinosine-polycytosine [poly (I:C)]. The growth of Miamiensis avidus was not affected by exposure to unstimulated or poly (I:C)-stimulated leucocytes alone, heat-inactivated immune serum alone, or unstimulated leucocytes plus heat-inactivated immune serum. However, leucocytes stimulated with poly (I:C) showed clearly high scuticocidal activity against M. avidus in the presence of heat-inactivated immune serum. Furthermore, numerous poly (I:C)-stimulated leucocytes occupied the surface of scuticociliates in the presence of the heat-inactivated immune serum, which led to lysis of scuticociliates. These results suggest that both of the stimulation of leukocytes and the immobilization of scuticociliates are necessary to kill scuticociliates by leukocytes.

A Study on Condensation Heat Transfer to Some Evaporated Metal Surface (각종증착금속면의 응축열전달에 관한 연구)

  • Jho Shi Gie;Lee Ki Woo;Park Young Jae;Cko Myong Jae
    • The Magazine of the Society of Air-Conditioning and Refrigerating Engineers of Korea
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    • v.15 no.2
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    • pp.188-195
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    • 1986
  • Condensation heat transfer can be classified in dropwise condensation and filmwise condensation, and for the industrial purpose, the former is more useful than the latter because of the higher heat transfer rate. But it is difficult to maintain the dropwise condensation continuously since most of the metal surfaces become wetted after exposure to a condensing vapor over an extended period of time. To maintain dropwise condensation continuously , various surface coatings and promoters have been used recently, but these methods must be reconsidered about the durability of condensing surface. Therefore, in this study, evaporating method of various pure metals on the condensing surface has been performed to maintain dropwise condensation. The results have showed that the heat transfer rate of silver evaporating surface is higher than any other metal evaporating in dropwise area. Transition temperature and filmwise condensation curves are uniform regardless of kinds of evaporating metals.

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Acceleration of heat shock-induced collagen breakdown in human dermal fibroblasts with knockdown of NF-E2-related factor 2

  • Park, Gunhyuk;Oh, Myung Sook
    • BMB Reports
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    • v.48 no.8
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    • pp.467-472
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    • 2015
  • Heat shock increases skin temperature during sun exposure and some evidence indicates that it may be involved in skin aging. The antioxidant response mediated by the transcription factor NF-E2-related factor 2 (Nrf2) is a critically important cellular defense mechanism that serves to limit skin aging. We investigated the effects of heat shock on collagenase expression when the antioxidant defense system was downregulated by knockdown of Nrf2. GSH and collagenases were analyzed, and the expression of inducible Nrf2, HO-1, and NQO1 was measured. HS68 cells were transfected with small interfering RNA against Nrf2. Heat shock induced the downregulation of Nrf2 in both the cytosol and nucleus and reduced the expression of HO-1, GSH, and NQO1. In addition, heat-exposed Nrf2-knockdown cells showed significantly increased levels of collagenase protein and decreased levels of procollagen. Our data suggest that Nrf2 plays an important role in protection against heat shock-induced collagen breakdown in skin. [BMB Reports 2015; 48(8): 467-472]

Effects of Heat Exposure and Restricted Feeding on Behavior, Digestibility and Growth Hormone Secretion in Goats

  • Hirayama, Takuji;Katoh, Kazuo
    • Asian-Australasian Journal of Animal Sciences
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    • v.17 no.5
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    • pp.655-658
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    • 2004
  • Heat stress is known to affect physiological systems in goats. This study investigated changes in nutrient digestibility, behavior and growth hormone secretion among goats in a hot environment (H; 35${\pm}$ 1.2$^{\circ}C$, [RH] 80${\pm}$7.2%, 13 d), and in a thermoneutral environment (T; 20${\pm}$0.6$^{\circ}C$, [RH] 80${\pm}$3.4%, 20 d), and accompanied by the same restricted diet as provided in the hot environment. The following results were obtained: rectal temperature and water intake were higher in the H treatment than in the T treatment or TR treatment, while hay consumption was lower. CP, NDF and ADF digestibility was highest in H treatment. Time spent eating in the H treatment was also the highest, followed in order by T treatment and TR treatment. Ruminating time was lower in H treatment than in T treatment or TR treatment, and reposing time was highest in the TR treatment. Growth hormone concentrations in T increased 4.5 h after feeding. In H, growth hormone concentrations increased 0.5 h after feeding. However, growth hormone concentrations were not changed following TR feeding. In conclusion, heat exposure in goats decreased feed intake, but increased digestibility. However, when goats in a thermoneutral environment received the same restricted feeding as they received in the hot environment, digestibility increased. Between the H treatment and TR treatment, the changes in digestibility were accomplished by coordinate changes in hormone secretion in order to maintain body homeostasis. To maintain energy balance under a hot temperature or a restricted feeding condition, goats may control their metabolism by changing growth hormone release.

Effect of Microwave Heat Treatment on Inhibition of Corn Seed Germination

  • Ambrose, Ashabahebwa;Lee, Wang-Hee;Cho, Byoung-Kwan
    • Journal of Biosystems Engineering
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    • v.40 no.3
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    • pp.224-231
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    • 2015
  • Purpose: Corn is a major commercial crop targeted for genetic modification owing to its high consumer demand as a foodstuff for humans and livestock, as well as its other industrial applications. However, the safety of genetically modified (GM) crops is controversial. Indeed, several countries have banned the importation of GM seeds that can germinate. Therefore, development of effective, convenient, and nondestructive methods to inhibit seed germination is required. Methods: This study aimed to examine the efficacy of microwave heat treatment for inhibition of germination of corn kernels and for optimization of power and exposure time required for effective aging treatment. Artificial inhibition was induced in corn kernels using microwave heat treatment. Seven power levels were examined (400, 500, 600, 700, 800, 900, and 1000 W) at each of the four exposure times (0.5, 1.0, 1.5, and 2.0 min). Results: Corn kernels could be aged effectively after heating for 0.5~1.0 min at powers greater than 800 W, with increasing efficacy observed at higher powers. Further analysis showed that the most effective inhibition of germination was observed at 1000 W for 40 s. This setting did not cause any physical damage to the corn kernels. Conclusions: Optimal inhibition of corn kernel germination was achieved using higher power for shorter times, which may be useful for industrial corn seed treatment.