• Title/Summary/Keyword: exposure time

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Application of 'Sponge Model' with Disinfectants for the Inhibition of Listeria monocytogenes (Listeria monocytogenes의 증식억제를 위한 살균제 'Sponge model'의 응용)

  • LEE Myung-Suk
    • Korean Journal of Fisheries and Aquatic Sciences
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    • v.29 no.5
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    • pp.595-602
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    • 1996
  • The antimicrobial effects of two disinfectants commonly used in food industry on Listeria monocytogenes ATCC 15313 were studied. The two disinfectants tested were commercial benzalkonium chloride (BAC) and sodium hypochlorite (NaOCl). Their effects were studied on cells suspended in disinfectants (in vitro) and in the sponge model with the disinfectants (in vivo). When cells were exposed to $0\~0.1\%$ BAC and $0\~150\;ppm$ NaOCL for 20 minutes, BAC and NaOCl concentration more than $0.25\%$ and 100 ppm showed the antimicrobial effects respectively. This organism decreased rapidly during the first $0.5\~1$ minute followed by a slower decrease during the rest of the exposure time. Fifteen ml of cell solution $(about\;10^7\;CFU/ml\;in\;the\;TSB)$ was mixed with 15 ml of disinfectants in the sponge $(6.0{\times}4.0{\times}4.0cm)$, BAC and NaOCl concentration more than $0.1\%$ and 300 ppm showed the antimicrobial effects, and at $0.25\%$ and 800 ppm diminished in cell numbers 3-log cycles during the first 20 minutes. In the case of sponge model, 15 ml of cell solution and 15 ml of disinfectants $(0.25\%\;of\;BAC,\;800\;ppm\;of\;NaOCl)$ were suspended in the sponge during 20 minutes, washing with 200 ml of sterilized distilled water, and this sponge was transfered in the 100 ml TBS, and then incubated at various temperature. The cells were increased about 1-log cycle during 24 hrs at $5\~15^{\circ}C$. And the others temperature, the cells growth was in proporation to storage tepmerature and the cells were about $10^9\;CFU/ml$ after $1\~3$ days incubations.

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Studies on Restoration of Forest-Floor Vegetation Devastated by Recreational Trampling (I) -Seeding, Fertilizing and Soil Surface Treatment Effect on Restoration of Forest-Floor Vegetation- (답압(踏壓)으로 훼손(毁損)된 임간나지(林間裸地)의 임상식생복원(林床植生復元)에 관한 연구(硏究)(I) -임상식생복원(林床植生復元)에 미치는 파종(播種), 시비(施肥) 및 표토처리효과 (表土處理效果)-)

  • Oh, Koo Kyoon;Woo, Bo Myeong
    • Journal of Korean Society of Forest Science
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    • v.81 no.1
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    • pp.53-65
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    • 1992
  • For elucidating effective methods of restoration of forest recreational sites where management goals are maintaining naturalness and conserving natural ecosystem, seeding, fertilization and soil surface treatment were used for four years at the devastated forest-floor. For restoration of forest-floor vegetation, factorial experiment was used with a split plot design(main plot : fertilization, subplot : soil surface${\times}$seeding) and a randomized complete block design (fertilization${\times}$seeding) at the Kwanaksan Aboretum, Anyang, Kyonggido. Results were summarized as follows : Soil surface softening with tipping and ripping and straw-mat mulching (70% coverage) treatment was effective on germination, survival and growth of seeded vegetation at devastated forest-floor. Especially, straw-mat mulching treatment was effective on soil surface stabilization and seedling's survival at eroded soil surface, while complete soil surface softening treatment was effective on germination, survival and early growth of tree species of late-successional series. Introducing seeds of native species of pioneer or early-successional series, with good growth capability in barren soil was effective on rapid restoration in devastated forest-floor with its soil surface previously compacted and its surviving seeds washed away. When the seeding and straw-mat mulching after partial soil surface softening with tipping and ripping treatment were employed, it took about three years to restore the devastated forest-floor where surface erosion had been undertaken for an extended period of time and where naturally surviving seeds of native species had been washed away. Softening treatment of soil surface was effective for about two years, and seeding and soil surface treatment increased number of seedlings and improved soil surface environment through fixing of movement of the fallen leaves. Fertilizing effect was not oberserved, mainly due to seeding exposure and poor physical condition including soil surface erosion, low soil water potential and drought, etc, at the field experimental site. However, application of nitrogen and phosphate fertilizers was effective on seedling survival of the species in late-successional series, while lime application adversely affected the seedling survival.

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Characterization of Arsenic Immobilization in the Myungbong Mine Tailing (명봉광산의 광미 내 비소의 고정화 특성 연구)

  • Lee, Woo-Chun;Jeong, Jong-Ok;Kim, Ju-Yong;Kim, Soon-Oh
    • Economic and Environmental Geology
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    • v.43 no.2
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    • pp.137-148
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    • 2010
  • The Myoungbong mine located in Boseong-gun, Jellanamdo consists of Au-Ag bearing quartz veins which filled the fissures of Bulguksa granitic rocks of Cretaceous. The tailings obtained from the Myungbong mine were used to investigate the effects of various processes, such as oxidation of primary sulfides and formation(alteration) of secondary and/or tertiary minerals, on arsenic immobilization in tailings. This study was conducted via both mineralogical and chemical methods. Mineralogical methods used included gravity and magnetic separation, ultrasonic cleaning, and instrumental analyses(X-ray diffractometry, energy-dispersive spectroscopy, and electron probe microanalyzer) and aqua regia extraction technique for soils was applied to determine the elemental concentrations in the tailings. Iron (oxy)hydroxides formed as a result of oxidation of tailings were identified as three specific forms. The first form filled in rims and fissures of primary pyrites. The second one precipitated and coated the surfaces of gangue minerals and the final form was altered into yukonites. Initially, large amounts of acid-generating minerals, such as pyrite and arsenopyrite, might make the rapid progress of oxidation reactions, and lots of secondary minerals including iron (oxy)hydroxides and scorodite were formed. The rate of pH decrease in tailings diminished, in addition, as the exposure time of tailings to oxidation environments was prolonged and the acid-generating minerals were depleted. Rather, it is speculated that the pH of tailings increased, as the contribution of pH neutralization reactions by calcite contained in surrounding parental rocks became larger. The stability of secondary minerals, such as scorodite, were deteriorated due to the increase in pH, and finally arsenic might be leached out. Subsequently, calcimn and arsenic ions dissociated from calcites and scorodites were locally concentrated, and yukonite could be grown tertiarily. It is confirmed that this tertiary yukonite which is one of arsenate minerals and contains arsenic in high level plays a crucial role in immobilizing arsenic in tailings. In addition to immobilization of arsenic in yukonites, the results indicate that a huge amount of iron (oxy)hydroxides formed by weathering of pyrite which is one of typical primary minerals in tailings can strongly control arsenic behavior as well. Consequently, this study elucidates that through a sequence of various processes, arsenic which was leached out as a result of weathering of primary minerals, such as arsenopyrite, and/or redissolved from secondary minerals, such as scorodite, might be immobilized by various sorption reactions including adsorption, coprecipiation, and absorption.

Expression profile of defense-related genes in response to gamma radiation stress (방사선 스트레스 반응 방어 유전자의 탐색 및 발현 분석)

  • Park, Nuri;Ha, Hye-Jeong;Subburaj, Saminathan;Choi, Seo-Hee;Jeon, Yongsam;Jin, Yong-Tae;Tu, Luhua;Kumari, Shipra;Lee, Geung-Joo
    • Journal of Plant Biotechnology
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    • v.43 no.3
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    • pp.359-366
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    • 2016
  • Tradescantia is a perennial plant in the family of Commelinaceae. It is known to be sensitive to radiation. In this study, Tradescantia BNL 4430 was irradiated with gamma radiation at doses of 50 to 1,000 mGy in a phytotron equipped with a $^{60}Co$ radiation source at Korea Atomic Energy Research Institute, Korea. At 13 days after irradiation, we extracted RNA from irradiated floral tissues for RNA-seq. Transcriptome assembly produced a total of 77, 326 unique transcripts. In plantlets exposed to 50, 250, 500, and 1000 mGy, the numbers of up-regulated genes with more than 2-fold of expression compared that in the control were 116, 222, 246, and 308, respectively. Most of the up-regulated genes induced by 50 mGy were heat shock proteins (HSPs) such as HSP 70, indicating that protein misfolding, aggregation, and translocation might have occurred during radiation stress. Similarly, highly up-regulated transcripts of the IQ-domain 6 were induced by 250 mGy, KAR-UP oxidoreductase 1 was induced by 500 mGy, and zinc transporter 1 precursor was induced by 1000 mGy. Reverse transcriptase (RT) PCR and quantitative real time PCR (qRT-PCR) further validated the increased mRNA expression levels of selected genes, consistent with DEG analysis results. However, 2.3 to 97- fold higher expression activities were induced by different doses of radiation based on qRT-PCR results. Results on the transcriptome of Tradescantia in response to radiation might provide unique identifiers to develop in situ monitoring kit for measuring radiation exposure around radiation facilities.

Predictive Value for Vesicoureteral Reflux in Children with Urinary Tract Infection (요로감염 환아에서 방광요관 역류를 예측할 수 있는 인자에 대한 연구)

  • Lee, Seung-Hyun;Noh, Sung-Hoon;Oh, Jeung-Eun;Kim, Min-Sun;Lee, Dae-Yeol
    • Childhood Kidney Diseases
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    • v.12 no.1
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    • pp.62-69
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    • 2008
  • Purpose: The most concerning issue in children with urinary tract infection(UTI) is the probability of underlying genitourinary anomalies and vesicoureteral reflux (VUR), which is frequently associated with renal scarring and eventually end-stage renal disease. Therefore, voiding cystourethrography(VCUG) is usually recommended at the earliest convenient time for children with UTI. However, VCUG is an invasive procedure that requires catheterization and exposure to X-ray. In this study, we aimed to determine the predictability of clinical, laboratory and imaging parameters for VUR in children with UTI. Methods: Data of children with bacteriologically proven UTI who underwent VCUG were evaluated retrospectively for clinical(age, gender, fever), laboratory(leukocytosis, ESR, CRP, pyuria, blood urea nitrogen, serum creatinine) and imaging(renal ultrasound and DMSA renal scan) findings. First, children with UTI were divided into two groups according to the presence of VUR as non-VUR group and with VUR group, and clinical, laboratory variables were compared between these groups. Second, patients who had VUR were reclassified as low-grade VUR(grade I-II) group and high-grade(grade III-V) VUR group according to grading of VUR, and clinical, laboratory and imaging variables were compared between these groups. Results: Among 410 children with UTI, 137 had VUR and 78 high-grade VUR. Fever, leukocytosis, ESR, CRP, pyuria were associated with VUR. In addition, abnormal findings of ultrasonography and DMSA renal scan were closely related to VUR. However, these clinical and laboratory variable in patients with high grade VUR were not different significantly, compared to those with low-grade VUR group. Conclusion: Fever, leukocytosis, ESR, CRP seems to be potentially useful predictors of VUR in pediatric patients with UTI. In addition, renal ultrasonography and DMSA renal scan findings supported the presence of VUR. Further study of these findings could limit unnecessary VCUG in patients with UTI.

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A Study on Total Mercury and Methylmercury in Commercial Tuna, Billfish, and Deep-sea Fish in Seoul Metropolitan City (서울시 유통 다랑어류, 새치류 및 심해성 어류의 총수은 및 메틸수은 축적에 대한 고찰)

  • Kim, Jin-Ah;Yuk, Dong-Hyun;Park, Young-Ae;Choi, Hee-Jin;Kim, Youn-Cheon;Kim, Moo-Sang
    • Korean Journal of Food Science and Technology
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    • v.45 no.3
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    • pp.376-381
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    • 2013
  • In this study, we monitored total mercury and methylmercury concentrations in tuna, billfish, and deep-sea fish distributed in Seoul city. With the acquired data, we carried out statistical analysis and an exposure assessment for intake. The mean concentrations (mg/kg) of total mercury and methylmercury were $0.32{\pm}0.31/0.20{\pm}0.20$ for tuna, $0.43{\pm}0.48/0.20{\pm}0.17$ for patagonian toothfish, $0.99{\pm}0.72/0.51{\pm}0.40$ for billfish and $1.20{\pm}0.70/0.95{\pm}0.51$ for sharks, respectively. We found that sharks, billfish, patagonian toothfish, and tuna were more contaminated with total mercury and methylmercury, in sequence, and that 66% of the total mercury concentration consisted of methylmercury, on average. Although the estimated weekly intakes of methylmercury from commercial deep-sea fish were lower than the weekly intakes recommended by the Joint FAO/WHO Expert Committee on Food Additives (JECFA), we identified that the total mercury and methylmercury concentrations in tuna, billfish, and deep-sea fish continued to increase with the passage of time. Therefore, we confirmed the necessity of continuous monitoring and comprehensive analysis for general safety.

Effect of Resveratrol on the Induction of Cdk Inhibitor p21 and Pro-apoptotic Bax Expression by amyloid-β in Astroglioma C6 Cells (신경교 세포에서 resveratrol이 amyloid-β에 의해 유도되는 Cdk inhibitor p21 및 Bax 발현의 감소 효과)

  • Kim Young Ae;Lim Sun-Young;Ko Woo Shin;Choi Byung Tae;Lee Yong Tae;Rhee Sook-Hee;Park Kun-Young;Lee Won-Ho;Choi Yung Hyun
    • Journal of Life Science
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    • v.15 no.2 s.69
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    • pp.169-175
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    • 2005
  • Resveratrol (3,4',5-trihydroxy-trans-stilbene), a phytoalexin found in grape skins, peanuts, and red wine, has been reported to have a wide range of biological and pharmacological properties. $Amyloid-\beta$ deposition and senile plaque-associated astrocytes are common neuropathological features of Alzheimer's disease. In this study, we have explored the effects of resveratrol on $amyloid-\beta-peptide-mediated$ cytotoxicity in vitro and modulation of cell growth-regulatory gene products in astroglioma C6 cells to elucidate its possible mechanism for anti-cytotoxicity. Exposure of C6 cells to $Amyloid-\beta$ resulted in dose-dependent growth inhibition and morphological changes of C6 cells, which were recovered by pre-treatment with resveratrol. The anti-proliferative effect of $amyloid-\beta$ was associated with the induction of tumor suppressor p53 and cyclin-dependent kinase (Cdk) inhibitor p21 (WAF1/CIP1) expression assessed by RT-PCR and Western blot analysis in time-dependent manner in C6 cells. In addition, the pro-apoptotic Bax expression was also up-regulated in $amyloid-\beta-treated$ C6 cells without alteration of anti-apoptotic Bcl-2 and $Bcl-X_L$ expression. However, pre-treatment of resveratrol significantly inhibited $amyloid-\beta-induced$ p53, p21 and Bax levels, suggesting that the modulation of p53, p21 and Bax levels could be one of the possible pathways by which resveratrol functions as anti-cytotoxic agent. Our results demonstrate that resveratrol may enhance the protection against $amyloid-\beta-induced$ cytotoxicity by promoting the survival of glial cells.

A Survey on the Effect of Crate Type and Harvest Season on Preslaughter Condition and Mortality of Broiler (어리장 형태와 계절이 육계 출하환경 및 폐사에 미치는 영향)

  • Kim Dong-Hun;Park Beom-Young;Hwang In-Ho;Cho Soo-Hyun;Kim Jin-Hyung;Lee Jong-Moon
    • Food Science of Animal Resources
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    • v.26 no.1
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    • pp.37-42
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    • 2006
  • The current study was conducted to investigate the effect of types of crate and season on transport condition and mortality, and ultimately to identify the best practice for reducing economic lose. Total loading weight stocking density, transport and lairage times and mortality were surveyed from the management data sheet of two companies for each first week of January, April, August and October, An average loading weight, length of transport and lairage times and mortality were 3.9 ton, 96 min, 478 min and 0.6%, respectively. Mortality after lairage was not significant between two types of crate. In addition, container type crate showed higher loading weight and stocking density than box type one. Spring and winter had significantly higher mortality with 0.7 and 0.8%, respectively, then summer and fell of 0.5%. An interaction between crate type and season on mortality showed that mortality for box type on was higher in spring and winter with 0.8 and 0.7%, respectively, compared to summer and fall of 0,3 and 0.4% respectively. In the case of container type crate, spring, fall and winter had greatly different death into with 0.7, 0.5 and 0.8%, respectively, while there was no difference between spring and summer, and between summer and winter, Mortality after transportation was similar between both crate type, with higher rate for spring and winder than other seasons. The result was likely related to death of exposure due to extended waiting time without heating facility.

Consideration on Measured Patients Dose of Three-Dimensional and Four-Dimensional Computer Tomography when CT-Simulation to Radiation Therapy (방사선치료를 위한 CT 검사 시 3DCT와 4DCT에 대한 피폭선량 고찰)

  • Park, Ryeong-Hwang;Kim, Min-Jung;Lee, Sang-Kyu;Park, Kwang-Woo;Jeon, Byeong-Cheol;Cho, Jeong-Hee;Yoo, Beong-Gyu;Lee, Jong-Seok
    • Journal of radiological science and technology
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    • v.34 no.4
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    • pp.341-349
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    • 2011
  • This study was to measure the patient dose difference between 3D treatment planning CT and 4D respiratory gating CT. Study was performed with each 10 patients who have lung and liver cancer for measured patient exposure dose by using SOMATON SENSATION OPEN(SIMENS, GERMANY). CTDIvol and DLP value was used to analyze patient dose, and actual dose was measured in the location of liver and kidney for abdominal examination and lung, heart and spinal cord for chest examination. Rando phantom were used for the experiment. OSLD was used for in-vitro and in-vivo dosimetry. Increasing overall actual dose in 4D respiratory gated CT-simulation using OSLD increase the dose by 5.5 times for liver cancer patients and 6 times for lung cancer patients. In CT simulation of 10 lung cancer patients, CTDIvol value was increased by 5.7 times and DLP 2.4 times. For liver cancer patients, CTDIvol was risen by 3.8 times and DLP 1.6 times. The accuracy of treatment volume could be increased in 4D CT planning for position change due to the breaths of patient in the radiation therapy. However, patients dose was increased in 4D CT than 3D CT. In conclusion, constant efforts is required to reduce patients dose by reducing scan time and scan range.

A Study on the Total Mercury (Hg) Monitoring and Methylmercury (MeHg) Analysis method and Exposure Assessment of Methylmercury (MeHg) in Marine Products (수산물 중 총수은 모니터링 및 메틸수은 분석법 고찰)

  • Kwak, Shin-Hye;Kim, Ki-Cheol;Kim, Kyung-A;Kang, Suk-Ho;Kwon, Hye-Jung;Cho, Yun-Sik;Kang, Kyung-Ja;Lee, Pil-Suk;Cho, Wook-Hyun;Moh, Ara;Park, Yong-Bae;Yoon, Mi-Hye
    • Journal of Food Hygiene and Safety
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    • v.33 no.3
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    • pp.168-175
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    • 2018
  • The use of microwave-assisted extraction and an acid-base clean-up process to determine the amount of methylmercury (MeHg) in marine products was suggested in order to improve the complicated sample preparation process. The optimal conditions for microwave-assisted extraction was developed by using a 10% NaCl solution as an extraction solution, setting the extraction temperature at $50^{\circ}C$, and holding for 15 minutes to extract the MeHg in marine products. A NaOH solution was selected as a clean-up substitute instead of L-cysteine solution. Overall, 670 samples of marine products were analyzed for total mercury (Hg). Detection levels were in the range of $0.0006{\sim}0.3801{\mu}g/kg$. MeHg was analyzed and compared using the current food code and the proposed method for 49 samples which contained above 0.1 mg/kg of Hg. Detection ranges of methylmercury followed by the Korea Food Code and the proposed method were $75.25(ND{\sim}516.93){\mu}g/kg$ and $142.07(100.14{\sim}244.55){\mu}g/kg$, respectively. The total analytical time of proposed method was reduced by more than 25% compared with the current food code method.