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        검색결과 9

        1.
        2023.11 구독 인증기관·개인회원 무료
        When decommissioning a nuclear power plant, it is expected that clearance or radioactive waste (e.g., soil, concrete, metal, etc.) below the low-level will be generated in a short period on a large scale. Among the various types of waste, most of the contaminated soil is known to be classified as clearance or the (very) low-level radioactive waste. Accordingly, an accurate measurement and classification of contaminated soil in real-time during the decommissioning process can efficiently reduce the amount of soil waste and the possibility of contamination diffusion. However, in order to apply a system that measures and classifies contaminated soil in real-time according to the level of contamination to the decommissioning site, a demonstration is required to evaluate whether the system is applicable to the site. In this study, to establish requirements for determining the applicability of the system to the decommissioning site, preceding cases from countries with abundant decommissioning experience were investigated. For example, MACTEC of the U.S. demonstrated the developed system at the Saxton nuclear power plant in the U.S. and confirmed that the amount of soil that can be analyzed per hour in the system is affected by radionuclides, minimum detectable activity (MDA), and applicable volume. In the future, therefore, we will utilize the result of this study to develop the requirements of demonstrating the system for measurement and classification of contaminated soil in real-time.
        2.
        2018.11 구독 인증기관·개인회원 무료
        Until recently, there have been many researches about the freezing methods and several methods of cryopreservation. Hypothermic preservation has been used to complement the embryo freezing technology. There is a study to show the successful results for long-term hypothermic preservation. For that reason, FBS and BSA are commonly added to the culture medium to support embryo development. We investigated the effectiveness of hypothermic preservation method at 4℃ according to embryonic developmental stages for Hanwoo embryos and evaluated the effect of FBS and BSA on Hanwoo embryos as a supplemental reagent in hypothermic preservation medium after recovering preserved embryos from hypothermic preservation. The present study reported that survival and hatching rates of embryos at morula stage following storage at 4℃ is Day 7 group was significantly higher (p < 0.05) compared than those of other groups (p < 0.05). As a result, the survival and hatching rates of embryos at the blastocyst stage following storage at 4℃ result is showed that significantly higher (p < 0.05) survival rates than those of other groups an Day 6. The result showed that hatching rate at Day 6 and 7 were significantly lower (p < 0.05) compared with other groups. The result regarding the survival and hatching rates of bovine embryos following storage at 4℃ for 72 h in various concentrations of BSA are shown The results showed that survival rate of 1% BSA group was not significantly different (p < 0.05) compare with control (FBS) group. Also, the results showed that hatching rate of control (FBS) and 1% BSA were significantly different (p < 0.05) compared with other groups. In conclusion, our result demonstrated that the hypothermic preservation did not effect on the survival and hatching rates of embryos after recovering. In addition, the supplementation of BSA in preservation medium showed no difference in the embryo developmental competence after hypothermic preservation compared to FBS treatment. With that, BSA can be an alternative reagent for the hypothermic preservation medium as an energy source and pH buffer.
        3.
        2018.11 구독 인증기관·개인회원 무료
        Cryopreservation of bovine embryos is used to efficiently implant surrogate mothers. It has been widely accepted that high lipid content in the oocyte interrupts its survival during freeze-thaw cycles. Serum component in the culture medium is thought to increase the embryo`s lipid contents. Conversely, L-carnitine stimulates lipid metabolism by transporting long chain fatty acids into the mitochondria. Objective of this study was to analyze the effect of L-carnitine supplementation in IVM medium and defined IVC medium on the development, lipid contents and the cryosurvival of bovine IVF embryos. 0.0, 1.5, 3.0 and 6.0 mM L-carnitine was supplemented in IVM medium, respectively (IVM-LC 0.0, LC 1.5, LC 3.0 and LC 6.0). Development rate from the 2cell to the morula stages was higher in IVM-LC 3.0 groups than those of IVM-LC 6.0 (p<0.05). But there were no significant differences among the other groups in the blastocyst rates and lipid content results. When 0.0, 1.5, 3.0 and 6.0 mM L-carnitine were supplemented in IVC medium (IVC-LC 0.0, LC 1.5, LC 3.0 and LC 6.0), development competence was not significantly different between those embryos. Lipid contents of embryos treated L-carnitine (IVC-LC 1.5, 3.0 and 6.0) were significantly lower than embryos of non-treated group. L-carnitine was supplemented 0.0, 1.5, 3.0, 6.0 mM during IVM and 3.0 mM during IVC (LC 0.0 - 3.0, LC 1.5 – 3.0, LC 3.0 – 3.0, LC 6.0 – 3.0) and cryosurvival of blastocysts confirmed after freezing-thawing. There were no significant differences on development, but LC 3.0 – 3.0 was significantly lower lipid contents than other groups. And LC 3.0 – 3.0 had better survival rates and hatched rates of blastocysts than LC 0.0 – 0.0. In conclusion, supplementation of L-carnitine in defined IVC medium decreases lipid contents. And L-carnitine supplementation improves cryosurvival and developmental ability of bovine IVF embryos.
        4.
        2018.11 구독 인증기관·개인회원 무료
        The early-onset familial Alzheimer's disease (EOFAD/ FAD), the less common type of Alzheimer's disease (AD) currently affects a vast number of individuals worldwide. This type is being inherited as an autosomal dominant fashion. Missense mutations on Amyloid precursor protein (APP) and Presenilins 1 and 2 (PSEN1 & PSEN2) are known as major genetic factors in FAD. Conversely, missense mutations on microtubule-associated protein tau (MAPT) are also thought to involve. Up to date, several triple-transgenic animal models with muted forms of the human APP, PSENs and MAPT have been reported. Compared to other animals, canines are more emotional and their disease signs can be easily diagnosed. This attempt was to develop a triple transgenic canine model for the AD. We have obtained the coding sequences of APP, PSEN1 and MAPT from Dana-Farber/Harvard Cancer Center DNA resource core at HMS and incorporated several common AD mutations. The transgenic construct is composed of hNSE (ENO2) promoter-driven three AD genes fused together with modified 2A sequences. It was transfected into the canine fetal fibroblasts which were then used to perform somatic cell nuclear transfer (SCNT). The viable transgenic embryos were obtained after in vitro culture and the GFP was detected. In this study, we have successfully produced viable triple transgenic canine cloned embryos using SCNT technique. These transgenic canine embryos will be further developed into canines with FAD. The transgenic canines will be a good candidate in the AD research field.
        5.
        2017.05 구독 인증기관·개인회원 무료
        Oocyte is the central factor in the bi-directional communication axis in the ovarian follicles. It controls the cumulus or granulosa cells to perform functions which are beneficial for its own development via secreting paracrine growth factors, including GDF9 and BMP15. The aim of this study was to investigate whether the recombinant GDF9 and BMP15 are able to promote meiotic resumption and cumulus expansion of canine COCs during IVM, as well as to demonstrate the actions of GDF9 and BMP15 in regulating the expression of connexin transcripts in the ovarian granulosa cells. As results, GDF9 and BMP15 significantly improved the meiotic resumption rate and cumulus expansion by activating ERK1/2 signaling. Treatments with GDF9 significantly improved the expression of CyclinB1 but inhibited the expression of Cx43 transcripts. In addition, cumulus expansion genes (MAPK1, Ptgs2, Tnfaip6 and Ptx3) were differentially improved by GDF9 and BMP15. In the ovarian granulosa cells, GDF9 suppressed the expression of Cx43 transcripts by binding ALK4/5/7 receptors and activation Smad2/3 signaling, whereas, BMP15 stimulated the expression of Cx43 transcripts by binding ALK2/3/6 receptors and activating Smad1/5/8 signaling. In conclusion, by regulating functions of granulosa/cumulus cells, oocyte has the potential to enhance the growth and maturation of itself.
        6.
        2017.05 구독 인증기관 무료, 개인회원 유료
        Oocyte is the central factor in the bi-directional communication axis in the ovarian follicles. It controls the cumulus or granulosa cells to perform functions which are beneficial for its own development via secreting paracrine growth factors, including GDF9 and BMP15. The aim of this study was to investigate whether the recombinant GDF9 and BMP15 are able to promote meiotic resumption and cumulus expansion of canine COCs during IVM, as well as to demonstrate the actions of GDF9 and BMP15 in regulating the expression of connexin transcripts in the ovarian granulosa cells. As results, GDF9 and BMP15 significantly improved the meiotic resumption rate and cumulus expansion by activating ERK1/2 signaling. Treatments with GDF9 significantly improved the expression of CyclinB1 but inhibited the expression of Cx43 transcripts. In addition, cumulus expansion genes (MAPK1, Ptgs2, Tnfaip6 and Ptx3) were differentially improved by GDF9 and BMP15. In the ovarian granulosa cells, GDF9 suppressed the expression of Cx43 transcripts by binding ALK4/5/7 receptors and activation Smad2/3 signaling, whereas, BMP15 stimulated the expression of Cx43 transcripts by binding ALK2/3/6 receptors and activating Smad1/5/8 signaling. In conclusion, by regulating functions of granulosa/cumulus cells, oocyte has the potential to enhance the growth and maturation of itself.
        4,000원
        7.
        2016.10 구독 인증기관·개인회원 무료
        A self-powered time-temperature indicator (TTI) was optimized to enhance the performance of the TTI by modifying a biofuel cell using different immobilization, redox mediators, and status of electrode. The performance of the TTI was measured by output voltage of the TTI. The enzymes and combinations of lacasse mediators (HBT (1-hydroxybenzotriazole), Rupy (Bis-(bipyridine)-(5-aminophenanthroline) ruthenium bis (hexafluorophosphate)), MB (Methylene blue), SDP (4,4- sulfonyldiphenol)) and glucose oxidase mediators (FA (Ferroceneboxaldehyde), DBQ(2,5-dihydroxybenzoquinone), HQS (8-hydroxyquinoline-5sulfonic acid hydrate), FHFP (Ferrocenium hexafluorophosphate)) were immobilized with stabilizers (pyrrole) on a glassy carbon electrode by electrodeposition by applying a square wave, cross-linking and physical immobilization. MWCNTs were used to modify glassy carbon electrodes. MWCNTs coated electrodes produced higher output voltage than uncoated electrodes. The optimum and stable performance of the self-powered TTI was that the output voltage of 64 mV and duration time was 3hr at 25°C, when the combination of Rupy, MB for laccase mediators and HQS, FHFP for glucose oxidase mediators were immobilized on MWCNTs coated electrodes by applying a square wave method. In the application, the concentrations of enzyme and glucose were adjusted to prolong the shelf-life of TTI at much lower output voltage.
        8.
        2016.10 구독 인증기관·개인회원 무료
        The pasteurization is employed for extending shelf-life and keeping the quality of products constant. However the pasteurization undesirably accelerates the oxidation of beer which renders volatile compounds concerning off-flavor. The pasteurization conditions was optimized to avoid off-flavor of beer during pasteurization. Under the isothermal condition, thermal destruction kinetics such as D and Z value of Lactobacillus brevis which is reported the most common beer spoilage, was determined. The binomial data (detected or non-detected of off-flavor) was treated with logistic regression to estimate off-flavor development (OFD) times. The temperature dependence of OFD times was established in terms of Arrhenius relationships. Optimized pasteurization temperature and time were found at which OFD times was not detected. The constraint for optimization was that the pasteurization degree should be larger than 5 decimal reduction time. The optimization was conducted through mathematical simulation using kinetics and temperature-dependent models for microbial death and OFD times. The optimized results were validated by the corresponding experimentations, which met the requirements that the concentration of Lactobacillus brevis was 5-Log reduction and the OFD times not detected.
        9.
        2016.10 구독 인증기관·개인회원 무료
        Time-temperature indicators or integrators (TTIs) indicate food quality changes based on time-temperature history. Whilst many types of TTIs have been developed and commercialized, educated consumers often refuse to purchase food products with attached TTI labels showing even a slight color change. In this study, a novel on-off diffusion-based TTI coupled with polydiacetylene/silica nanocomposites has been proposed. The prototype TTI tag has a multilayer structure comprised of a self-adhesive base layer, a middle microporous sheet, and an upper opaque white layer coupled with a square reservoir of Tween 20 attached to an activation stripe. At the end of the diffusion path, polydiacetylene/silica nanocomposites were injected into a loading site as a fine blue stripe. After activation, Tween 20 diffused and reached the loading site, where it rapidly changed from blue-to-red via solvatochromism. This alternative and innovative TTI continuously showed a blue color until reaching the end point, at which stage a red color rapidly appeared, indicating product rejection. Thus, this novel TTI it is of great benefit to the brand owner. The developed prototype was characterized and evaluated for its ability to monitor microbial quality based on published, isothermal, microbial growth data of modified-atmosphere packaged minced beef, Mediterranean fish, and ground pork. The diffusion of Tween 20 in the TTI system was measured under various isothermal conditions and a kinetic model, based on the association between diffusion and time-temperature, was investigated. The Gaussian-estimated activation energy value was 51.082kJ mol-1. Tween 20 diffusion of 6.10, 5.15 and 6.15mm along the TTI systems were considered to be end points and the 95% confidence interval between the times taken for TTI to display OFF and for the foods to reach their deterioration thresholds were 23.30-23.70, 23.00-23.50 and 23.44-24.05h for total aerobic bacteria, Shewanella putrefaciens, and Pseudomonas spp. respectively. The TTI performance test for reproducibility and accuracy revealed a normal frequency distribution with 35004.90, 1200.254.82 and 549.811.09min at 0, 11 and 25C, respectively in accordance with the investigation of diffusion in the TTI.