• Title/Summary/Keyword: exposure duration

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Cadmium Toxicity on the Survival Rate and Activity of the Equilateral Venus, Gomphina veneriformis (Bivalvia: Veneridae) (대복 (Gomphina veneriformis)의 생존 및 운동성에 미치는 카드뮴 (cd)의 독성)

  • PARK Jung Jun;LEE Jung Sick
    • Korean Journal of Fisheries and Aquatic Sciences
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    • v.36 no.5
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    • pp.463-468
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    • 2003
  • This study observed change of survival rate, activity and foot structure of the equilateral venus (Gomphina veneriformis) exposed to cadmium. Survival rate and activity of the clam exposed to cadmium was reduced with increase of exposure duration and concentration. Change of survival rate and activity was observed in the early exposure time (7 days) in the condition of above 1 77 mg/L and 0.88 mg/L, respectively. Activity reduction of the clam exposed to cadmium seems to be caused by epidermal layer deformation, muscle fiber fragmentation and muscular layer collapse of the foot.

Metabolomic Response of Chlamydomonas reinhardtii to the Inhibition of Target of Rapamycin (TOR) by Rapamycin

  • Lee, Do Yup;Fiehn, Oliver
    • Journal of Microbiology and Biotechnology
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    • v.23 no.7
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    • pp.923-931
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    • 2013
  • Rapamycin, known as an inhibitor of Target of Rapamycin (TOR), is an immunosuppressant drug used to prevent rejection in organ transplantation. Despite the close association of the TOR signaling cascade with various scopes of metabolism, it has not yet been thoroughly investigated at the metabolome level. In our current study, we applied mass spectrometric analysis for profiling primary metabolism in order to capture the responsive dynamics of the Chlamydomonas metabolome to the inhibition of TOR by rapamycin. Accordingly, we identified the impact of the rapamycin treatment at the level of metabolomic phenotypes that were clearly distinguished by multivariate statistical analysis. Pathway analysis pinpointed that inactivation of the TCA cycle was accompanied by the inhibition of cellular growth. Relative to the constant suppression of the TCA cycle, most amino acids were significantly increased in a time-dependent manner by longer exposure to rapamycin treatment, after an initial down-regulation at the early stage of exposure. Finally, we explored the isolation of the responsive metabolic factors into the rapamycin treatment and the culture duration, respectively.

Several issues regarding the diagnostic imaging of medication-related osteonecrosis of the jaw

  • Kim, Jo-Eun;Yoo, Sumin;Choi, Soon-Chul
    • Imaging Science in Dentistry
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    • v.50 no.4
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    • pp.273-279
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    • 2020
  • This review presents an overview of some diagnostic imaging-related issues regarding medication-related osteonecrosis of the jaws(MRONJ), including imaging signs that can predict MRONJ in patients taking antiresorptive drugs, the early imaging features of MRONJ, the relationship between the presence or absence of bone exposure and imaging features, and differences in imaging features by stage, between advanced MRONJ and conventional osteomyelitis, between oncologic and osteoporotic patients with MRONJ, and depending on the type of medication, method of administration, and duration of medication. The early diagnosis of MRONJ can be made by the presence of subtle imaging changes such as thickening of the lamina dura or cortical bone, not by the presence of bone exposure. Most of the imaging features are relatively non-specific, and each patient's clinical findings and history should be referenced. Oral and maxillofacial radiologists and dentists should closely monitor plain radiographs of patients taking antiresorptive/antiangiogenic drugs.

A Study on the character of Urban Entertainment Center in multi-anchor and exposure time - Focusing on Cheongryanri station and Yongsan station - (집객시설과 노출시간에 따른 도심 엔터테인먼트형 복합상업시 설(UEC)의 특징에 관한 연구 - 청량리역과 용산역을 중심으로 -)

  • Kim, Hyeongjung
    • Korean Institute of Interior Design Journal
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    • v.22 no.1
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    • pp.283-290
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    • 2013
  • The change of shopping environment created new emerging type of shopping center after 1990's, Urban Entertainment Center(UEC) in northen America. One hand traditional shopping center was retail-centered, the other hand UEC is entertainment-centered and offers the trinity of synergy. Each components, that are retail, dining and entertainment, play a role of drawing people, extending duration of visiting and making people revisit then the synergy makes commercial profit in shopping center. As northen America many of shopping centers with complex have been built in Korea since 2000 and some projects is planning by the change of shopping environment and regenerating urban. Although the term of "UEC" is used in Korea, it seems to be added entertainment facilities to shopping center without considering on commercial strategy. This study will take a look at mix and duration of visit which ULI stresses in UEC development and comparing with those of Yongsan Station and Chyeongrangri Station which are built recently in seoul, it will get characters and situation of these UECs. Finally, the analysis is to be used as a planning data in UEC development.

Development of Copper Corrosion Products and Relation between Surface Appearance and Corrosion Rate

  • Tran, Thi Ngoc Lan;Nguyen, Thi Thanh Binh;Nguyen, Nhi Tru;Yoshino, Tsujino;Yasuki, Maeda
    • Corrosion Science and Technology
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    • v.7 no.2
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    • pp.99-111
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    • 2008
  • Copper was exposed unsheltered and sheltered in four humid tropical sites, representing urban, urban-industrial, urban-marine and rural environments. The corrosion rates and the sequence of corrosion product formation are presented and discussed in relation with climatic and atmospheric pollution parameters. Chemical compositions of corrosion products were found to depend on environments and duration of exposure. In all environments, cuprite was the predominating corrosion product that formed first and continuously increased during the exposure. Among the sulphur-containing corrosion products, posnjakite and brochantite were more frequently found and the first formed earlier. Nantokite was the most common chlorine-containing products for most cases, except the high-chloride environment, where atacamite was detected instead. The corrosion rate of copper was well indicated by the colour of patina. The red-purple colour corresponded to the high corrosion rate and the greenish grey colour corresponded to the low corrosion rate. Corrosion rate of sheltered copper in urban-marine environment increased with the exposure time.

Effect of a 20 kHz Sawtooth Magnetic Field Exposure on the Estrous Cycle in Mice

  • Jung, Kyung-Ah;Ahn, Hae-Sun;Lee, Yun-Sil;Gye, Myung-Chan
    • Journal of Microbiology and Biotechnology
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    • v.17 no.3
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    • pp.398-402
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    • 2007
  • Abstract Female mice post weaning were exposed to 20 kHz sawtooth electric and magnetic fields (EMF) with $6.25{\mu}T$ peak intensity for 6 weeks. Estrous cycles were checked using vaginal smears over the last 10 days of the experimental period. The vaginal smears from EMF-exposed mice revealed an increase in the frequency of one or two phases persisting. The number of estrous cycles less than 1 was more in the EMF-exposed group than in the sham control group. Furthermore, in the EMF-exposed group, the duration of proestrous and metestrous stages of the estrous cycle was significantly increased compared with the control group. In conclusion, our results suggest that exposure to 20 kHz sawtooth EMF may affect normal cycling of the estrous cycle by disrupting the female reproductive endocrine physiology. We should not disregard the possible adverse reproductive effect of the 20 kHz sawtooth EMF generated under the occupational exposure situation in females.

Effects of periodic air-exposure and nutrients on the competition of Ascophyllum nodosum and Fucus vesiculosus germlings

  • Park, Seo Kyoung;Choi, Han Gil;Nam, Ki Wan
    • Korean Journal of Environment and Ecology
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    • v.29 no.1
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    • pp.7-13
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    • 2015
  • To examine the relationship between competition and environmental factors, the germlings of Ascophyllum nodosum (L) Le Jolis and Fucus vesiculosus L. were cultured in monocultures and mixtures of the two species under two different exposure and nutrient levels. Both intra- and inter-specific competition were examined in comparison of the mortality and growth of germlings in monocultures and mixtures of the two species. The mortality of germlings increased with increasing density and emergence periods both in the monoculture and mixtures of the two species, and the mortality of Ascophyllum was significantly higher than that of Fucus both in submerged and emerged treatments. The growth of germlings of both species reduced with increasing density but F. vesiculosus always grew faster than Ascophyllum. The values of log output ratio were more than 0.1, indicating that Fucus 'won' in the competitive battles with Ascophyllum under two nutrient- and air-exposure levels. Log output ratio was greater in high than in low nutrients, indicating that the growth of Fucus is more enhanced than that of Ascophyllum in high nutrients. In the present study, the outcome of inter specific competition between germlings of Fucus vesiculosus and Ascophyllum nodosum was slightly altered by duration of emergence and nutrient concentration, but not to such an extent as to change the outcome.

Analysis of Chromosome Aberrations and Micronuclei in Peripheral Lymphocytes of Nurses in a Hospital (병원 근무 간호사들의 염색체 이상 및 소핵 빈도에 미치는 위험요인)

  • Jeon Hye Jeong;Kim Tae Hwan;Choi Soo Yong;Chung Hai won
    • Environmental Mutagens and Carcinogens
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    • v.25 no.4
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    • pp.150-156
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    • 2005
  • Analysis of chromosome aberration (CA) and cytokinesis-block micronucleus (CBMN) assay in peripheral lymphocytes of nurses exposed to low levels of anticancer drug and Ethylene Oxide(EO) gas in a hospital were performed. The frequency of CA was increased in the exposed compared to the controls whereas no increase of the frequency of MN was found. The frequencies of chromatid type CA were 1.2, 3.91 and 9.67 per 500 cells in the controls, workers exposed to anticancer drug and workers exposed to EO, respectively. Lower frequency of CA in nurses handling anticancer drugs with safety covers compared to those without safety covers was observed, but it was not statistically significant. The frequency of CA in nurses handling anticancer drugs increased by the frequency of mixing anticancer drugs. Poisson regression analysis showed a significant association of the frequency of chromatid type CA with age, duration of wort exposure to anticancer drug and EO gas exposure, but no association of the frequency of chromosome type CA with any variables. The results suggested that there were associations between CA and the occupational exposure to low levels of anticancer drug and EO gas.

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Chemical Inhibition of Cell Recovery after Irradiation with Sparsely and Densely Ionizing Radiation

  • Evstratova, Ekaterina S.;Kim, Jin-Hong;Lim, Young-Khi;Kim, Jin Kyu;Petin, Vladislav G.
    • Journal of Radiation Industry
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    • v.10 no.4
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    • pp.199-204
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    • 2016
  • The dependence of cell survival on exposure dose and the duration of the liquid-holding recovery (LHR) was obtained for diploid yeast cells irradiated with ionizing radiation of different linear energy transfer (LET) and recovering from radiation damage without and with various concentrations of cisplatin - the most widely used anticancer drug. The ability of yeast cells to recover from radiation damage was less effective after cell exposure to high-LET radiation, when cells were irradiated without drug. The increase in cisplatin concentration resulted in the disappearance of this difference whereas the fraction of irreversible damage was permanently enlarged independently of radiation quality. The probability of cell recovery was shown to be constant for various conditions of irradiation and recovery. A new mechanism of cisplatin action was suggested according with which the inhibition of cell recovery after exposure to ionizing radiations was completely explained by the production of irreversible damage.

The Measurement of Physical Properties of Outdoor Exposed Members

  • Kim, Gwang-Chul;Kim, Jun-Ho
    • Journal of the Korean Wood Science and Technology
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    • v.47 no.3
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    • pp.311-323
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    • 2019
  • The number of newly constructed traditional Korean houses, i.e., Hanoks, and light-frame buildings is increasing. However, related research is limited owing to the lack of awareness regarding safety evaluations. Therefore, this study conducted an outdoor exposure test to accurately evaluate wooden constructions. Spruce, pine, and fir (SPF) material was monitored for a year, wherein the SPF material was artificially dried under 18% moisture content, and its physical properties and color differences were measured once a month. Large differences were observed in the material's weight and moisture content, which are indexes sensitive to daily range and rainfall; however, no significant difference was found for other basic properties in the pre and post test results. Herein, $L^*$, $a^*$, and $b^*$ values represent color differences; these values exhibited a general decrease after the test. Such differences were attributed to the loss of lignin in the wood. The color difference value was high between the months of May and July, when the daily range and rainfall significantly fluctuated. Multiple regression analysis was performed on the $a^*$ value (redness indicator), daily range, rainfall, and ultraviolet index. The results indicated that the daily range influenced redness the most. According to the estimated regression equation, the daily range and redness are positively correlated. Based on the results, the types and influence of independent variables on color difference are expected to change as the wood's duration of outdoor exposure and the amount of data obtained both increase.