• Journal of Microbiology and Biotechnology
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• v.15 no.1
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• pp.175-182
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• 2005

Abstract Salmonella pathogenicity island 1 (SPI1) gene expression is regulated by many environmental signals such as oxygen, osmolarity, and pH. Here, we examined changes in the expression level of various regulatory proteins encoded within SPI1 in response to three different concentrations of NaCl, using primer extension analysis. Transcription of all the regulatory genes tested was activated most when Salmonella were grown in Luria Broth (LB) containing 0.17 M NaCl. The expression of hilA, invF, and hilD was decreased in the presence of 0.47 M NaCl or in the absence of NaCl, while hilC expression was almost constant regardless of the NaCl concentration when Salmonella were grown to exponential phase under low-oxygen condition. The reduced expression of hilA, invF, and hilD resulted in lower invasion of hilC mutant to the cultured animal cells when the mutant was grown in the presence of 0.47 M NaCl or in the absence of NaCl prior to infection. Among the proteins secreted via the SPI1-type III secretion system (TTSS), the level of sopE2 expression was not influenced by medium osmolarity. Various effects of osmolarity on virulence gene regulation observed in this study is one example of multiple regulatory pathways used by Salmonella to cause infection.

• Journal of dental hygiene science
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• v.5 no.2
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• pp.83-88
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• 2005

In spite of relatively low level of radiation dose used at dental clinics, long term exposure may be harmful, so radiation workers at dental clinics must be well aware of its danger. This study was radiation safety management by dental hygienists in order to take preventive measures for dental hygienists and suggest ideas to develop radiation safety training programs. For this, we contacted dental hygienists working at the local dental clinics for 4 months from December of 2003 to march of 2004 and obtained the following findings. 1. Regarding the intraoral radiographic method, the average daily photographing frequency of standard films stood at one to five pieces (47.5%), and the average weekly photographing frequency of digital radiation medicine stood at less than one piece (69.8%), and the average weekly photographing frequency of bitewing films stood at less than one piece (67.7%), and and the average weekly photographing frequency of occlusal films stood at less than one piece (95.5%), and the dentistries whose average weekly photographing frequency of pediatric films stood at one to five pieces accounted for 47.1 percent. 2. Regarding the extraoral radiographic method, the average weekly photographing frequency of panorama film stood at one to five pieces (63.7%), and less than one piece (20.9%), the average weekly photographing frequency of cephalometric film stood at less than one piece (72.3%), and one to five pieces (20.1%). 3. Concerning the radiation safety management training program, only 18.7% of total 278 surveyed attended the training progra., Attendance tendency of the training program by general characteristics showed statistically significant difference according to age (p<0.01), working experience (p<0.001), and marital status (p<0.01). 4. When asked about the protective equipments against radiation exposure, 40.6% of them said "modest", and 71.1% appeared equipped with led apron as a protective tool.

• Journal of Society of Preventive Korean Medicine
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• v.20 no.1
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• pp.145-159
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• 2016

Objectives : The aim was to investigate the characteristics of low dose effect and non monotonic dose responses(NMDRs) and to predict the influence it might have on the health and medicine, traditional Korean medicine. Methods : By investigating recently published major literatures related to low dose effect and NMDRs, the definition, mechanism, major related fields, and the influence on public health and medicine has been categorized and summarized. Results : Although there are still heated debates about the definition of low dose, it implies the biological responses in environmental exposure level and the NDMDRs means the nonlinear relationship between the dose-response in the slope sign change. Also, it implies the new form of the curve showing a U, reverse U shape, and the slop sign constantly changing showing various forms. This mechanism is because the two acceptor shows opposing effects to toxic materials and the affinity is different along with the numerical value that increase and decrease being different. These characteristics generally appear in endocrine disrupters such as bisphenol A, agricultural pesticides, metal, and radiation. The research field in the public health and medical treatment is obesity, problems in metabolism, growth hormone treatment, climacteric treatment, breast cancer, intake of Korean traditional medicine for pregnancy, menopause and phytoestrogen. Conclusions : As a result of discussing implications, NMDRs is a particular effect in low dose and heated debates surround this response, research is being conducted surrounding the field of obesity, problems in metabolism, growth hormone treatment, climacteric treatment, breast cancer, intake of Korean traditional medicine for pregnancy, menopause, and phytoestrogen. More research and interest in needed as it can have a massive influence in the public health and medicine.

• Korean Journal of Environmental Agriculture
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• v.19 no.4
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• pp.309-313
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• 2000

To investigate the effects of different UV-B levels on growth and biochemical defense response in plants, cucumber plants were subjected to three levels of biologically effective ultraviolet-B $(UV-B_{BE})$ radiation [daily dose: 0.03 (No), 6.40 (Low) and $11.30\;(High)\;kJ{\cdot}m^{-2}$, $UV-B_{BE}$] in the growth chambers for 3 weeks during the early growth period. Enhanced UV-B radiation drastically decreased both dry weight and leaf area of cucumber. With increasing UV-B intensity, chlorophyll content was decreased, however the level of malondialdehyde was highly increased linearly. Total contents of ascorbic acid and glutathione were tended to increase by UV-B, while the ratios of dehydroascorbate/ascorbate and oxidized glutathione/reduced glutathione were significantly increased with increasing UV-B intensity in cucumber. All the enzyme activities investigated (superoxide dismutase, ascorbate peroxidase, dehydroascorbate reductase, guaiacol peroxidase etc.) in cucumber were increased by the UV-B enhancement. These results suggested that enhanced UV-B irradiation caused photooxidative stress in cucumber plant and resulted in significant reduction in plant growth. Biochemical protection responses might be activated to prevent the leaves from damaging effects of oxidative stress generated by UV-B irradiation.

• The Journal of Fisheries Business Administration
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• v.50 no.2
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• pp.23-40
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• 2019

The main purpose of this study is to analyze and examine the problems of the law systems of the safety and maintenance of nuclear facilities and to propose the improvements with respect to the related problems especialy focused on safety management of aquatic products. Therefore, the results of the paper would be helpful to build an effective management law system of safety and maintenance of nuclear facilities and fisheries products. The research methods are longitudinal and horizontal studies. This study compares domestic policies with foreign policies of nuclear plants and aquatic products. Using the above methods, examining the current system of nuclear-related laws and regulations, we have found that there exist 13 Acts including "Nuclear Safety Act", etc. Safety laws related on nuclear facilities have seven Acts including "Nuclear Safety Act", "the Act on Physical Protection and Radiological Emergency", "Radioactive waste control Act", "Act on Protective Action Guidelines against Radiation in the Natural Environment", "Special Act on Assistance to the locations of facilities for disposal low and intermediate level radioactive waste", "Korea Institute of Nuclear Safety Act". "Act on Establishment and Operation of the Nuclear Safety and Security Commission". The seven laws are composed of 119 legislations. They have 112 lower statute of eight Presidential Decrees, six Primeministrial Decrees and Ministrial Decrees, 92 administrative rules (orders), 6 legislations of local self-government aself-governing body. The concluded proposals of this paper are as follows. Firstly, we propose that the relationship between the special law and general law should be re-established. Secondly, the terms with respect to law system of safety and maintenance of nuclear plants should be redefined and specified. Thirdly, it is advisable to re-examine and re-establish the Law System for Safety and Maintenance of Nuclear Facilities. and environmental rights like the French Nuclear Safety Legislation. Lastly, inadequate legislation on the aquatic pollution damage should be re-established. It is necessary to ensure sufficient transparency as well as environmental considerations in the policy decisions of the Korean government and legislation of the National Assembly. It is necessary to further study the possibilities of accepting the implications of the French legal system as a legal system in Korea. In conclusion, the safety management of nuclear facilities is not only focused on the secondary industry and the tertiary industry centering on power generation and supply, but also on the primary industry, which is the food of the people. It is necessary to prevent damage to be foreseen. Therefore, it is judged that there should be no harm to the people caused by contaminated marine products even if the "Food Safety Law for Prevention of Radiation Pollution Damage" is enacted.

• Journal of Radiation Protection and Research
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• v.35 no.3
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• pp.117-123
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• 2010

Plutonium is by far the most important of the transuranic elements which have been released into the environment due to radio-toxicity and long term radiation effects on humans. And Pu isotope ratio ($^{240}Pu/^{239}Pu$) is of great interest because this ratio is used as a fingerprint for different sources. Mass spectrometry has been used as an useful atom counting technique with several advantages over decay counting techniques for the determination of Pu isotopes. It enables a determination of Pu isotope ratio in the environmental samples with a low detection limit and a short determination time. An ICP-MS is the representative mass spectrometry for Pu determination. In this study, the precision of $^{240}Pu/^{239}Pu$ isotope ratio was improved by using 4 multiple ion counters of MC-ICP-MS. The detection limit of $^{239}Pu$ and $^{240}Pu$ were $0.10\;fg\;ml^{-1}$ ($0.24\;{\mu}Bq\;ml^{-1}$), $0.12\;fg\;ml^{-1}$ ($0.97\;{\mu}Bq\;ml^{-1}$), respectively. The relative standard deviation of $^{240}Pu/^{239}Pu$ isotope ratio was less than 1 % in trace level. The various reference materials (seawater, soil and sediment) were analyzed to verify this method and their analytical results were in good agreement with the certified (or recommended value) value.

• Korean Journal of Veterinary Research
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• v.42 no.1
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• pp.1-6
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• 2002

The frequencies of gamma-ray-induced micronuclei (MN) in cytokinesis-blocked (CB) lymphocytes at several doses were measured in three donors of three species (human, rabbit, dog). Measurements performed after irradiation showed a dose-related increases in MN frequency in each of the donors studied. When analysed by linear-quadratic model the line of best fit was : human : $y=0.1184D+0.01867D^2+0.01$, rabbit : $y=0.0387D+0.00528D^2+0.01$ (y = number of MN/CB cells and D = irradiation dose in Gy). The relative sensitivity of rabbit lymphocytes compared with human lymphocytes was estimated by best fitting linear-quadratic model based on the radiation-induced MN data over the range from 0 Gy to 4 Gy. In the case of MN frequency with 0.2, the relative sensitivities of rabbit lymphocytes was 0.39. These data indicate that the induction of MN in rabbit CB cells following irradiation was much less sensitive to the MN induction effects of gamma-irradiation than those from human. The MN assay with dog lymphocytes was very difficult and time-consumed because the dog PHA-stimulated lymphocytes yielded cultures with very low level of CB cells formation in the condition of this experiment. Our in vitro radiobiological study confirmed that the cytogenetic response obtained in blood from rabbit can be utilized for application in environmental studies.

• Journal of IKEEE
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• v.23 no.2
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• pp.743-746
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• 2019

In this paper we proposed a new ocean radiation automatic monitoring system. The proposed system has the following characteristics: First, using NaI + PVT mixed detectors, the response speed is fast and precision analysis is possible. Second, the application of temperature compensation algorithm to scintillator-type sensors does not require additional cooling devices and enables stable operation in the changing ocean environment. Third, since cooling system is not needed, electricity consumption is low, and electricity can be supplied reliably by utilizing solar energy, which can be installed at the observation deck of ocean environment. Fourth, using GPS and wireless communications, accurate location information and real-time data transmission function for measurement areas enables immediate warning response in the event of nuclear accidents such as those involving neighboring countries. The results tested by the authorized testing agency to assess the performance of the proposed system were measured in the range of $5{\mu}Sv/h$ to 15mSv/h, which is the highest level in the world, and the accuracy was determined to be ${\pm}8.1%$, making normal operation below the international standard ${\pm}15%$. The internal environmental grade (waterproof) was achieved, and the rate of variation was measured within 5% at operating temperature of $-20^{\circ}C$ to $50^{\circ}C$ and stability was verified. Since the measured value change rate was measured within 10% after the vibration test, it was confirmed that there will be no change in the measured value due to vibration in the ocean environment caused by waves.

• Journal of the Korean Society of Radiology
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• v.4 no.4
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• pp.5-10
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• 2010

The $Ca_2SiO_4$ phosphors doped by La with 0.1 wt%, 0.3 wt%, 0.5 wt%, and 1.0 wt% concentration were prepared by sintering at $1000^{\circ}C$ for 90 minutes in N2 atmosphere. The phosphors were ground in powdered form and were grouped in $100{\mu}m$ size, then the samples had been exposed to low energy X-ray and UV light. The TL glow curves were measured by heating the phosphors at $10^{\circ}C/s$ rate. There was no significantly meaningful correlation between the TL intensity and the doping level. The intensities of the TL peak measured from X-ray irradiated samples doped with 0.1 wt% were relatively strong. The activation energy and the frequency factor were 0.434 ~ 0.516 eV and 0.5 ~ 0.56, respectively. The intensities of the TL peak measured from UV irradiated samples doped with 0.3 wt% were relatively strong. The activation energy and frequency factor were 0.415 ~ 0.477 eV and 0.5 ~ 0.53, respectively. The TL process were found to be the 2nd order for both X-ray and UV irradiation. The TL intensity was increased linearly with the increase of the radiation dose. In summary, the $Ca_2SiO_4 phosphors developed in this study showed good TL characteristics at low energy X-ray and UV light. We believe they will be used as TLDs in near future for personal and environmental radiation detection dosimetry.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.45 no.8
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• pp.686-696
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• 2017

The major objective of this study is to develop and verify the KAUSAT-5 based on the modular 3U CubeSat standard platform. In the mechanical system design of a 3U standard platform, subsystem and micro equipment functions/performance should be integrated and miniaturized on micro-sized PCBs and electrical capability was maximized to accommodate multiple payloads. KAUSAT-5 is 3U-sized Cubesat which will be operated in Low Earth Orbit(LEO), which implements mainly two scientific missions; one is to observe the Earth through infrared camera and the other is to measure space radiation with a Geiger Muller tube. An additional mission is to verify the equipment(device) such as VSCMG and fuzzy logic-based MPPT internally developed. The results of ETB, qualification and acceptance level environmental tests were shown to verify standard platform and KAUSAT-5 Cubesat.