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        검색결과 21

        1.
        2024.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Since rice is the main food in Korea, there are no regulations on corn milling yet. Corn is known as one of the world's top three food crops along with wheat and rice, and it is known that 3.5 billion people worldwide use corn for food. In addition, corn mills are not developed or sold in Korea, but the use of corn mills is increasing significantly in many countries in Southeast Asia. In the Philippines, as Korea's rice mill import increases, Korea's KAMICO (Korea Agricultural Machinery Industry Cooperative) and domestic company A agreed to develop a corn mill jointly with PHilMech, an organization affiliated with the Philippine Ministry of Agriculture. However, research on corn milling was very insignificant, so the development was carried out based on the technology of Korea's rice mill. Rice milling is performed by peeling off the skin of rice and producing brown or white rice, so it is carried out by removing the skin and cutting the skin. On the other hand, in the corn mill, the skin of the corn is peeled, pulverized and selected to produce main products suitable for edible use. Therefore, in order to develop a corn mill, processes such as peeling, transfer, grinding, sorting, and by-product separation are required, and suitable parts must be developed. In addition, the performance must be gradually improved through experiments in which corn is repeatedly milled. The Philippines produces 7.98 million tons/year of corn, which is about 100 times that of Korea, and is mostly consumed as a staple food. This is about 10% of the total crop production in the Philippines. In addition, the main cultivation complexes of corn are the mountainous regions of Tarlac or Pangasinan, and the produced corn is 72.4% of the so-called yellow corn called Arabel and Sarangani, and the remaining 27.6% are known as white corn. In this study, it was intended to produce grains of 2.5 mm or less suitable for food for yellow corn and to develop a corn mill for 200 kg per hour. Detailed conditions for development are stipulated as more than 55% of the main product recovery rate, more than 31% of the by-product recovery rate, less than 5% of the raw material loss rate, and more than 80% of the embryo dislocation rate. In this study, to achieve this, the overall process of the corn mill was developed, and the optimal conditions for the corn mill were obtained through the development of parts and empirical tests to improve performance. In addition, it was intended to achieve the development goal by evaluating and analyzing the performance of each part so that it did not conflict.
        4,800원
        2.
        2023.11 구독 인증기관·개인회원 무료
        EU taxonomy requires to solve problems for safe management of radioactive waste and disposal of spent fuel, which is a precondition for growing demand for nuclear power plant. Currently, Korea manages about 18,000 tons of high-level radioactive waste at temporary storage facilities in nuclear power plant sites, but such temporary storage facilities are expected to become saturated sequentially from 2031. Therefore, it is necessary to secure a permanent disposal facility to safely treat high-level radioactive waste. In accordance with the second basic plan for high-level radioactive waste management in 2021, it is necessary to establish requirements for regulatory compliance for the site selection and site acquisition, investigation and evaluation, and construction for the establishment of a deep geological disposal facility. In this study, we analyzed the regulatory policies and cases of leading foreign countries related to deep geological disposal facilities for high-level radioactive waste disposal waste such as IAEA, USA, Sweden, and Finland using data analysis methodology. To analyze a large amount of textbased document data, text mining is applied as a major technology and a verification standard that secures validity and safety based on the regulatory laws described so far is developed to establish a regulatory base suitable for domestic deep geological disposal status. Based on the collected data, preprocessing and analysis with Python were performed. Keywords and their frequency were extracted from the data through keyword analysis. Through the measured frequency values, the contents of the objects and elements to be regulated in the statutory items were grasped. And through the frequency values of words co-occurring among different sections through the analysis of related words, the association was obtained, and the overall interpretation of the data was performed. The results of analyzing regulations of major foreign countries using text mining are visualized in charts and graphs. Word cloud can intuitively grasp the contents by extracting the main keywords of the contents of the regulations. Through the network connection graph, the relationship between related words can be visually structured to interpret data and identify the causal relationship between words. Based on the result data, it is possible to compare and analyze the factors to be supplemented by analyzing domestic nuclear safety case and regulations.
        4.
        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.
        5.
        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.
        6.
        2019.10 KCI 등재 서비스 종료(열람 제한)
        소아의 선천적 심장질환 진단을 위해 High Pitch Mode를 사용하여 획득한 소아 심장 CT 영상과 Wide Co verage Volume Axial Mode를 사용하여 획득한 소아 심장 CT 영상으로부터 환자의 피폭선량과 각 영상의 화질을 비교 및 분석하여 Wide Coverage Volume Axial Mode의 유용성을 평가해보고자 한다. 소아 심장 CT 검사 시 High Pitch Mode와 Wide Coverage Volume Axial Mode를 각각 50명 총 100명의 환자를 대상으로 시행하였으며, 각 프로토콜로부터 얻은 영상을 이용하여 환자의 피폭선량을 비교하였다. 각 영상에 ROI를 설정해 SNR과 CNR을 산출하여 영상의 화질을 비교하였다. High Pitch Mode에 비해 Wide Coverage Volume Axial Mode를 사용하여 검사하였을 때 환자의 피폭선량이 13.07% 감소하였고, SNR과 CNR이 향상되었다. Wide Coverage Volume Axial Mode는 고속 회전 스캐너를 이용하여 조사시간을 줄이고, 저선량 기술인 ASi R-V를 통해 High Pitch Mode를 사용했을 때보다 환자의 피폭선량이 감소하고 영상의 화질 또한 향상되는 유용한 검사라 할 수 있다.
        7.
        2017.08 서비스 종료(열람 제한)
        Spatiotemporal expressions of microRNAs (miRNAs) are altered by the physiological states of cells which could be influenced by microenvironment. Function of miRNAs has been focused as a new regulator of gene expressions and cell differentiation in human health and diseases. We found and identified the several miRNAs, which were related to developmental competence of preimplantation and implantation process of mouse blastocysts and outgrowth embryos by microarray-based bioinformatical studies. In this study, we evaluated three miRNAs expressions related to third cleavage event in conditioned media (CM) and blastocysts. Mouse 2-cell stage embryos were collected and monitored for 9 hours. The embryos were divided two groups as early third cleavage before 9 hours of collection and late third cleavage after 9 hours of collection. They were cultured to blastocyst stage up to day-5 after hCG injection. The total number of cells and the number of cells with fragmented DNA were assessed in blastocysts by terminal dUTP nick-end labelling (TUNEL) staining and DAPI staining. Mean cell number of early third cleavage group was significantly higher than that of late third cleavage group (105.3±8.0 vs 81.8±7.0, p<0.05), but apoptotic index was not different. The miRNAs of CM and blastocysts from early and late group were prepared, and quantified by qRT-PCR with TaqMan probes. The expression levels of three miRNAs (mmu-let-7b, mmu-miR-183, and mmu-miR-429) in CM and blastocysts were slightly upregulated in late third cleavage group. Our study suggested that the expression level of miRNAs could be altered with embryo quality, and miRNAs in CM may be used to predict miRNAs expression of embryos and developmental competence.
        8.
        2016.10 서비스 종료(열람 제한)
        Background : Senna tora L. is a herbaceous plant affiliated to legumes. It has many components good for health with emodin, chrysophanol, aloe-emodin, physicion, rhein, obtusin. It is believed to have many medicine effects, as well as to good for the eyes. This study carried to find ou t the difference of characteristics on the growth according to the planting date used plugs. Plu g plants are very useful for transplanting. It gives well-management effects to the farmer such a s time, plant health, and maximum potential state during the raised time. Methods and Results : Plug plants had 30 days in raising seeding. The planting date was five time. Fist planting date was late April. The last planting date was early July. In their raising seeding period they were taken care of in the green house. And after 30 days, they were planted on the ground in planting density of 50*40cm sized area with three repeat treatments. When the raising seeding period, the length of plant and the length of leaf were the highest at the middle May, respectively. The number of leaf per plant was highest in late May as 11. In the planting period, the length of plant was highest at early July. The lowest was the length of plant at late May. Except the stem diameter in early April, they were no differences among other treatments and the stem diameter was the highest in early April. The number of node per plant could be found the most in middle May and late April. The number of node per plant was the lowest in early July. In the respect of yield, middle May had the highest yield than that of other treatments. It was 849.0kg/10a. The lowest was 740.6kg/10a in the early May. Conclusion : About the characteristics on the growth of Senna tora L. according to the planting date, the yield of middle May was highest than that of other date in this study. The planting date of late May had also shown strong tendency of optimum planting date. Therefore middle May and late May of planting date would be optimum planting date.
        9.
        2015.09 서비스 종료(열람 제한)
        The blastocyst should initiate the dynamic changes in morphology and gene expression during hatching and implantation. Blastocyst morphogenesis includes two major events as the formation of blastocoel cavity for lineage differentiation into trophectoderm and inner cell mass, and the blastocyst hatching for implantation. However, there is little known about the relation of dynamic morphogenesis in blastocyst with hatching and implantation potential. In this study, we investigated effects of the dynamic morphogenesis in blastocyst on hatching and implantation potential by outgrowth assay. The cumulative time between each stages was calculated and analyzed. The feature of contraction was evaluated as follows: the number of contractions and the period of circumference was measured. The percentage of reduction during contraction was classified as weak when it was less than 20% and as strong when 20% or more. Compared to embryos of hatching group, embryos of non-hatching group were significantly delayed time at the compacted morula stage by 375.3 min (p<0.05) and at the early blastocyst stage by 650.1 min (p<0.01), respectively. Compared to blastocysts of outgrowth group, blastocysts of non-outgrowth group were significantly delayed at the compacted morula by 404.0 min (p<0.01) and at the early blastocyst stage by 535.4 min (p<0.01), respectively. There is no significant difference in the feature of contraction between hatching and non-hatching groups. However, blastocyst of outgrowth group showed more number of weak contraction and less number of strong contractions, compared with blastocysts of non-outgrowth group (p<0.01). Period of circumference was not significantly different in hatching and outgrowth process. These results suggested that time of blastocoel formation and number of weak contraction in blastocysts were closely related to hatching and outgrowth potential. Dynamic changes of blastocyst formation and contraction could be useful markers to select embryos for predicting the success implantation and pregnancy in human ART program.
        10.
        2014.09 서비스 종료(열람 제한)
        The aim of this study was to evaluate the efficacy of tenofovir in HBV patients at 12 months after treatment. A total of 122chronic hepatitis B patients who took tenofovir for at least 12 months were enrolled. We measured ALT levels, HBeAg, anti-HBe, HBV DNA, and serum creatinine at six and 12 months after treatment. The virological response rate at six and 12 months after treatment in naïve patients was 27.1% and 41.7%, respectively. High virological response rate at six and 12months after treatment showed an association with initial low HBV DNA titer and initial negative HBeAg status.
        11.
        2014.09 서비스 종료(열람 제한)
        The aim of this study was to analyze the effect of antifreeze proteins (AFPs) on vitrification of mouse mature (MII) oocytes. We studied about 3 types of AFPs from different origins (FfIBP, LeIBPand Type III AFP). The MII oocytes were obtained from 4-week-old BD-F1 mice. Vitrification of oocyte was performed by 2 steps using the Cryotop (equilibration: 7.5% EG + 7.5% PROH for 5 min, vitrification: 15% EG + 15% PROH + 0.5M sucrose for 1 min). The concentrations of AFPs added to these solutions were 0.05 mg/ml for FfIBP and 0.1 mg/ml for LeIBP and Type III AFP. After fertilization, embryo development was assessed up to 5 days. Through immunostaining of vitrified-warmed oocytes, we assessed the normal meiotic spindle. Also, intracellular ROS and mitochondrial activity was analyzed. In the developmental stages, FfIBP and LeIBP groups showed significantly higher survival rates. In the blastocyst and apoptotic blastomere rates were significant differences in AFPs treated groups. AFPs treated groups were significantly higher in blastocyst cell numbers than control group. Among the AFPs treated groups, FfIBP, LeIBP groups were significantly higher rates. And, in cleavage rates, FfIBP group was significantly higher rates than the other groups. In vitrified-warmed MII oocytes, the normal meiotic spindle organization and chromosome alignment rate was significantly higher in FfIBP and LeIBP groups. And in intracellular ROS levels, control group was significantly increased than AFPs treated groups. However, in the mitochondrial activity, LeIBP group was significantly higher than control, FfIBP and LeIBP groups. AFPs treated groups were significant differences in development, meiotic spindle organization and intracellular ROS levels. And in the AFPs treated groups, FfIBP and LeIBP groups were significantly higher rates in normal meiotic spindle and mitochondrial activity than Type III AFP group respectively. In conclusion, FfIBP and LeIBP can be thought to improve oocyte cryopreservation efficiency.
        12.
        2014.09 서비스 종료(열람 제한)
        The follicle loss of transplanted ovarian tissue (OT) is caused by ischemia and slow revascularization. To shorten the ischemic period and promote angiogenesis, some angiogenic factors have been treated for transplanted tissues. Angiopoietin-2 (ANG-2) is one of the major angiogenic factors and has been reported to promote blood vessels and increase vascular permeability in the ischemic and/or hypoxic environment. So, this study was designed to assess the impact of ANG-2 on follicle integrity and revascularization of mouse OT grafts. The 5-week-old B6D2F1 female mice were divided into 3 groups (a control and 2 ANG-2 groups) followed by ovary collection and vitrification. After warming, the ovaries were autotransplanted into kidney capsules with/without ANG-2 injection (50 or 500 ng/kg), and then killed at day(D)2, 7, 21 and 42 after transplantation. Total 2,437 follicles in OT grafts were assessed for the follicular density, integrity and classification by H&E staining. Apoptosis, revascularization, and serum FSH levels were evaluated by TUNEL assay, CD31 immunohistochemistry, and ELISA respectively. All the ANG-2 groups showed remarkable increase of morphologically intact follicle ratio across all the grafting duration except D21 (no statistical difference). The numbers of CD31(+) vessels (the sum of 3 fields at ×400 magnification) were significantly increased in both ANG-2 groups compared with the control group at all the grafting duration. Especially at D42, the 500ng ANG-2 group showed significantly more vessels than the 50 ng ANG-2 group as well as the control group. However the mean follicle numbers of grafts, apoptosis ratio and serum FSH levels showed no significant difference among the groups. In this study, remarkably well preserved follicles and larger amount of vessels were appeared in ANG-2 treated groups. So we thought that ANG-2 treatment is effective for OT transplantation and improve transplantation outcomes.
        13.
        2014.09 서비스 종료(열람 제한)
        Polyethyleneglycol-adsorbed–superoxide dismutase (PEG-SOD), has been proposed as an effective agent for reducing free radical-mediated injury. The objective of this study was to investigate a protective effect of PEG-SOD supplementation on ovarian tissue during transplantation. Ovaries from F-1 mice were collected and vitrified. After warming, ovaries were autotransplanted under kidney capsule. Mice were randomly divided into four groups according to dose of PEG-SOD, (0 U/ml, 100 U/ml, 1,000 U/ml and 10,000 U/ml respectively). Grafted ovaries were retrieved 2, 7 and 21 days later. PEG-SOD was treated by intraperitoneal injection once every 48 hours and especially for 21 days group, after first week treatment, PEG-SOD was treated once every 4 days. Morphology of ovaries was assessed histological analysis and ELISA for FSH was performed to evaluate restoration of ovarian function. In 2 days groups, morphologically intact follicle ratio of 10,000 U/ml group was significantly higher than other groups. In 7 days groups, morphologically intact follicle ratio was significantly higher in all treatment groups. In 21 days groups, there was no significant difference of intact follicle ratio in total follicles in all groups but intact primordial, primary and secondary follicles ratio was higher in 10,000 U/ml group. FSH levels in blood serum were decrease as time goes on, but there is no statistical difference in each groups. In conclusion, the data of the present study show that PEG-SOD has a beneficial effect on preservation of the morphologically intact follicle.
        14.
        2014.09 서비스 종료(열람 제한)
        Ovarian tissue cryopreservation and transplantation causes follicle depletion. To overcome this problem, we investigate the effect of Anti-Müllerian hormone (AMH), a follicle recruitment control hormone, supplementation before and/or after mouse ovarian transplantation. A total of 120 5-week-aged BD F-1 female mice were used. The mice were randomly divided into four groups according to AMH doses (0, 5, 25, 125 μg/mL, respectively). AMH was injected intraperitoneally on every other day for a week before, after, or before and after transplantation of ovaries under kidney capsules was performed. One week after transplantation, follicular normality was evaluated by histological analysis and TUNEL assay. In Group A and C, morphologically intact follicle (G1) ratios of AMH treated groups showed no statistically significant difference. In Group B, G1 ratios of 25 and 125 μg/mL of AMH treated groups were higher than those of 5 μg/mL treated group, but there was no improvement in G1 ratio after AMH treatment. In every group, apoptotic follicle ratios did not show any trend according to AMH treatment. Proportions of primordial follicle were not significantly different according to AMH treatment in all groups. The result of the present study demonstrated that AMH treatment during on transplantation of cryopreserved ovaries has no significant effect on follicle survival and prevention of follicle depletion.
        15.
        2014.09 서비스 종료(열람 제한)
        Objective : To investigate the effects of Simvastatin and Methylprednisolone on ovarian tissue cryopreservation and transplantation using mouse models. Methods : The mice were randomly distributed into 1 control and 3 experimental groups. The B6D2F1 mice were given oral Simvastatin (5 mg/kg), intravenous Methylprednisolone (15 mg/kg), or a combination of both at 2 hours before ovariectomy. Same volume of normal saline was given perorally in the control group at 2 hours before ovariectomy. The ovarian tissues were vitrified accrording to our protocols. The vitrified ovaries were warmed 1 week later and auto-transplanted under bilateral kidney capsules. The ovaries and blood sera were collected at 2, 7 or 21 days after transplantation. Histological analysis, TUNEL assay, immuno-histochemistry for CD31, serum AMH level and embryonic development after in vitro fertilization were assessed for evaluation. Results : With regard to the total grade 1 follicle rate, both Simvastatin or Methylprednisolone treated groups were significantly increased at 2, 7 or 21 days after transplantation (except Simvastatin treated group at 7 days). A combination of Simvastatin and Methylprednisolone group was significantly improved in terms of the total G1 follicle rate, apoptotic follicle rate, CD31 positive area and serum AMH after ovarian tissue transplantation. However, there were no statistically difference with respect to the oocyte maturation rate, blastulation rate, and the other embryonic development parameters after in vitro fertilization procedure among the four groups. Conclusion : Our results suggest that combined donor Simvastatin and Methylprednisolone have beneficial effects on the quality and function of transplanted ovarian tissues.
        16.
        2014.09 서비스 종료(열람 제한)
        Study question: What is the optimal vitrification protocol according to the cryoprotective agent (CPA) for ovarian tissue (OT) cryopreservation? Summary answer: The two-step protocol with 7.5% ethylene glycol (EG) and 7.5% dimethyl sulfoxide (DMSO) for 10 min then 20% EG, 20% DMSO and 0.5 M sucrose for 5 min showed the best results in mouse OT vitrification. What is known already: Establishing the optimal cryopreservation protocol is one of the most important steps to improve OT survival. However, only a few studies have compared vitrification protocols with different CPAs and investigated the effect of in vitro culture (IVC) on vitrified–.warmed OT survival. Some recent papers proposed that a combination of CPAs has less toxicity than one type of CPA. However, the efficacy of different types and concentrations of CPA are not yet well documented. Study design, size, duration: A total of 644 ovaries were collected from 4-week-old BDF1 mice, of which 571 ovaries were randomly assigned to 8 groups and vitrified using different protocols according to CPA composition and the remaining 73 ovaries were used as controls. After warming, each of the eight groups of ovaries was further randomly divided into four subgroups and in vitro cultured for 0, 0.5, 2 and 4 h, respectively. Ovaries of the best two groups among the eight groups were autotransplanted after IVC. Participants/materials, setting, methods: The CPA solutions for the eight groups were composed of EDS, ES, ED, EPS, EF, EFS, E and EP, respectively (E, EG; D, DMSO; P, propanediol; S, sucrose; F, Ficoll). The IVC medium was composed of a-minimal essential medium, 10% fetal bovine serum and 10 mIU/ml follicle-stimulating hormone (FSH). Autotransplantation of vitrified–.warmed OTs after IVC (0 to 4 h) using the EDS or ES protocol was performed, and the grafts were recovered after 3 weeks. Ovarian follicles were assessed for morphology, apoptosis, proliferation and FSH level. Main results and the role of chance: The percentages of the morphologically intact (G1) and apoptotic follicles in each group at 0, 0.5, 2 and 4 h of IVC were compared. For G1 follicles at 0 and 4 h of IVC, the EDS group showed the best results at 63.8 and 46.6%, respectively, whereas the EP group showed the worst results at 42.2 and 12.8%, respectively. The apoptotic follicle ratio was lowest in the EDS group at 0 h (8.1%) and 0.5 h (12.7%) of IVC. All of the eight groups showed significant decreases in G1 follicles and increases in apoptotic follicles as IVC duration progressed. After autotransplantation, the EDS 0 h group showed a significantly higher G1 percentage (84.9%) than did the other groups (42.4–.58.8%), while only the ES 4 h group showed a significant decrease in the number of proliferative cells (80.6%, 87.6–.92.9%). However, no significant differences in apoptotic rates and FSH levels were observed between the groups after autotransplantation. Limitations, reasons for caution: The limitation of this study was the absence of in vitro fertilization using oocytes obtained from OT grafts, which should be performed to confirm the outcomes of ovarian cryopreservation and transplantation. Wider implications of the findings: We compared eight vitrification protocols according to CPA composition and found the EDS protocol to be the optimal method among them. The data presented herein will help improve OT cryopreservation protocols for humans or other animals.
        17.
        2012.09 서비스 종료(열람 제한)
        Human embryonic stem cells (hESCs) are promising cell source because of their unique self-renewal and pluripotency. Although hESC-derived cardiac cells are currently generated worldwide, cryopreservation of these cells is still limited due to low rate of post-thaw survival. Cryopreservation of hESC-derived cardiac cells is critical in that their long-term storage can accelerate their use in regenerative medicine. However, to date, there are few reports on efficient cryopreservation and post-thaw survival of hESC-derived cardiac cells. In this study, we evaluated the effects of ginsenoside, which is known to improve survival of rat embryonic cardiomyocytes against myocardial ischemia injury in diabetic rats (Wu et al., 2011), on the survival of hESC-derived cardiac cells after thawing. We induced differentiation into cardiac cells using our previously reported method (Kim et al., 2011). Differentiated, pre-beating stage cardiac cells were cryopreserved using either mass cryopreservation or vitrification. To evaluate the effects of ginsenoside (Re, Rb), we compared three sets: pre- and post-thaw treatment, pre- or post-thaw treatment only. The survival of post-thaw cardiac cells were evaluated using Trypan-blue and Annexin V staining. In addition, the three groups were treated with ROCK inhibitor Y-27632, and compared with non-treatment groups. The effect of ginsenoside was significant in post-thaw treatment group, i.e, thawed cells expressed cardiac specific genes and showed specific functionality such as spontaneous beating. Taken together, we demonstrated favorable effects of ginsenoside on the survival of hESC-derived cardiac cells after cryopreservation and thawing. These results suggest a possible application of well-known cardioprotectant ginsenoside in cell-based tissue engineering using hESC-derived cardiac cells.
        18.
        2012.07 서비스 종료(열람 제한)
        Development of transgenic plant with desirable traits to cultivated plant is one of the important procedures in plant molecular breeding. However, applicable assessment of transgenic plant in laboratorial scale is not much except cultivating transgenic plant for a whole life in field condition. Here, we analyzed chlorophyll fluorescence in three transgenic soybean lines with AtMYB44 transcription factor for assessment of photosynthetic activity under abiotic stresses such as drought. Soybean varieties used in this study were ‘Bert’ and ‘Bert’ derived three transgenic soybeans, ‘AtMYB44 CM35101’, ‘AtMYB44 CM2471’, and ‘AtMYB44 CM4481’. Analyzed five different chlorophyll fluorescence variables are maximum PSII quantum yield (QY_max), steady state PSII quantum yield (QY_Lss), steady state non-photochemical quenching (NPQ_Lss), coefficient of photochemical quenching in steady-state (Qp_Lss), and fluorescence declineratio in steady-state (Rfd_Lss). To determine main chlorophyll fluorescence variable affected by abiotic stress, principal component analysis (PCA) was conducted with five chlorophyll fluorescence variables measured from four varieties. QY_Lss and NPQ_Lss were main chlorophyll fluorescence variables to evaluate abiotic stress, particularly in drought stress. In comparison with transgenic soybean lines based on chlorophyll fluorescence variables, ‘AtMYB44 CM2471’ and ‘AtMYB44 CM4481’ are more tolerant to drought than the others. Interestingly, three transgenic soybean lines which have a same AtMYB44 gene with different regions of chromosome revealed the quite different responses of chlorophyll fluorescence to drought treatment.
        19.
        2011.09 서비스 종료(열람 제한)
        Human embryonic stem cells (hESCs) have the potential for use in regenerative medicine and in the field of basic research. Therefore, effective cryopreservation and storage of hESCs are important for preservation of newly established cell line for various purposes. Despite poor survival and slow recovery after thawing, the conventional slow freezing method is most commonly used for cryopreservation of hESCs due to its simplicity and ease of use for freezing a large number of hESCs appropriate to clinical applications. Here we controlled the clump size (Group Ⅰ; 400~450 ㎛, Group Ⅱ; 800~900 ㎛, and Group Ⅲ; 1500~1700 ㎛) of hESCs at 5 days after plating using a glass pipette during cryopreservation in order to obtain a larger amount of hESCs after thawing. Attachment rates differed significantly (P<0.05) in each of the three groups and the average of attachment rate of GroupⅡ was highest in SNUhES4 and H1. In particular, the attachment rate of Group Ⅱ in SNUhES3 showed a significant improvement with ROCK inhibitor Y-27632. These results indicate that clump size and cell-cell adhesions of GroupⅡ are appropriate for cryopreservation compared to the Group Ⅰ and Group Ⅲ. This method increased cell viability and reduced the recovery time leading to various experiments, and therefore has an advantage for use with hESCs like newly established in particular. We demonstrated that use of this effective cryopreservation method with control of the clump size of hESCs can effectively improve the attachment rate and survival of post-thaw hESCs with and without Y-27632.
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