• Nuclear Engineering and Technology
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• v.33 no.1
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• pp.12-24
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• 2001

The post-LOCA long term cooling (LTC) performance of the Korean Standard Nuclear Power Plant (KSNPP) is analyzed for both small break loss-of-coolant accidents (LOCA) and large break LOCA at cold leg. The RELAP5/MOD3.2.2 beta code is used to calculate the LTC sequences based on the LTC plan of the Korean Standard Nuclear Power Plants (KSNPP). A standard input model is developed such that LOCA and the followed LTC sequence can be calculated in a single run for both small break LOCA and large break LOCA. A spectrum of small break LOCA ranging from \ulcorner.02 to 0.5 k2 of break area and a double-ended guillotine break are analyzed. Through the code calculations, the thermal-hydraulic behavior and the boron behavior are evaluated and the effect of the important action including the safety injection tank (SIT isolation and the simultaneous injection in LTC procedure is investigated. As a result, it is found that the sufficient margin is available in avoiding the boron precipitation in the core. It is also found that a further specific condition for the SIT isolation action need to be setup and it is recommended that the early initiation of the simultaneous injection be taken for larger break LTC sequences.

• YAKHAK HOEJI
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• v.56 no.1
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• pp.26-34
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• 2012

Mast cells play an important role in early and late phase allergic reactions through allergen and IgE-dependent release of histamine, proteases, prostaglandins, and several multifunctional cytokines. In this study, we investigated whether Cudrania tricuspidata extract (CTE) suppresses IgE-mediated allergic responses in mast cells, an allergic animal model, and its mechanism of action in mast cells. We found that CTE inhibited IgE-mediated degranulation and cytokine production in rat basophilic leukemia (RBL)-2H3 mast cells and bone marrow-derived mast cells (BMMC), as well as passive cutaneous anaphylaxis (PCA) in mice. With regard to its mechanism of action, CTE suppressed the activating phosphorylation of spleen tyrosine kinase (Syk), a key enzyme in mast cell signaling processes and that of LAT, a downstream adaptor molecule of Syk in $Fc{\varepsilon}RI$-mediated signal pathways. CTE also suppressed the activating phosphorylation of mitogen-activated protein (MAP) kinases and Akt. The present results strongly suggest that the anti-allergic activity of CTE is mediated through inhibiting degranulation and allergic cytokine secretion by inhibition of Syk kinase in mast cells. Therefore, CTE may be useful for the treatment of allergic diseases.

• The Korean Journal of Physiology
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• v.30 no.1
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• pp.97-104
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• 1996

Different neural substrates have been reported to be implicated in analgesic mechanisms in the acute phasic and the sustained tonic pains. To explore the differential antinociceptive action of diphenylhydantoin (DPH) and carbamazepine (CBZ) on the acute phasic and the tonic pains, changes in tail flick latency, hot plate latency and the formalin-induced nociceptive score were assessed prior to and after intraperitoneal administration of DPH (20 & 40 mg/Kg) and CBZ (20 mg/Kg). In 11 rats, CBZ was administered repeatedly for 6 days at the dose of 20 mg/Kg/day. Also studied were the effects of strychnine and picrotoxin (1 mg/Kg, i.p.) on the CBZ-produced changes in the formalin-induced pain behaviors. The tail flick and hot plate ltencies were not changes after administration of DPH and CBZ. However DPH strongly suppressed the formalin-induced tonic pain. A single and the repeated administration of CBZ inhibited both the early phasic and the late tonic pain responses to formalin in n similar manner. On the other hand, the antinociceptive actions of CBZ were not altered by strychnine or picrotoxin. These experimental findings lead to the conclusion that DPH and CBZ have differential antinociceptive action on the acute and the tonic pains and that their antinociceptive actions are independent of the GABA- and glycine-receptors.

• Molecules and Cells
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• v.38 no.3
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• pp.236-242
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• 2015

Intake of caffeine during pregnancy can cause retardation of fetal development. Although the significant influence of caffeine on animal development is widely recognized, much remains unknown about its mode of action because of its pleiotropic effects on living organisms. In the present study, by using Caenorhabditis elegans as a model organism, the effects of caffeine on development were examined. Brood size, embryonic lethality, and percent larval development were investigated, and caffeine was found to inhibit the development of C. elegans at most of the stages in a dosage-dependent fashion. Upon treatment with 30 mM caffeine, the majority ($86.1{\pm}3.4%$) of the L1 larvae were irreversibly arrested without further development. In contrast, many of the late-stage larvae survived and grew to adults when exposed to the same 30 mM caffeine. These results suggest that early-stage larvae are more susceptible to caffeine than later-stage larvae. To understand the metabolic responses to caffeine treatment, the levels of expression of cytochrome P450 (cyp) genes were examined with or without caffeine treatment using comparative microarray, and it was found that the expression of 24 cyp genes was increased by more than 2-fold (p < 0.05). Among them, induction of the cyp-35A gene family was the most prominent. Interestingly, depletion of the cyp-35A family genes one-by-one or in combination through RNA interference resulted in partial rescue from early larval developmental arrest caused by caffeine treatment, suggesting that the high-level induction of cyp-35A family genes can be fatal to the development of early-stage larvae.

• Molecules and Cells
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• v.40 no.1
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• pp.17-23
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• 2017

Mitogen-activated protein kinase (MAPK) signaling cascades play critical roles in various cellular events in plants, including stress responses, innate immunity, hormone signaling, and cell specificity. MAPK-mediated stress signaling is also known to negatively regulate nitrogen-fixing symbiotic interactions, but the molecular mechanism of the MAPK signaling cascades underlying the symbiotic nodule development remains largely unknown. We show that the MtMKK5-MtMPK3/6 signaling module negatively regulates the early symbiotic nodule formation, probably upstream of ERN1 (ERF Required for Nodulation 1) and NSP1 (Nod factor Signaling Pathway 1) in Medicago truncatula. The overexpression of MtMKK5 stimulated stress and defense signaling pathways but also reduced nodule formation in M. truncatula roots. Conversely, a MAPK specific inhibitor, U0126, enhanced nodule formation and the expression of an early nodulation marker gene, MtNIN. We found that MtMKK5 directly activates MtMPK3/6 by phosphorylating the TEY motif within the activation loop and that the MtMPK3/6 proteins physically interact with the early nodulation-related transcription factors ERN1 and NSP1. These data suggest that the stress signaling-mediated MtMKK5/MtMPK3/6 module suppresses symbiotic nodule development via the action of early nodulation transcription factors.

• The Journal of the Convergence on Culture Technology
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• v.7 no.3
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• pp.19-25
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• 2021

The purpose of this study is to explore the effectiveness of teacher education using applications. To do this, we conducted research on pre-school teachers. To summarize the performance of the study, it is as follows. Teacher training was conducted through music creation activities. The subjects of the study were 56 students(29 experimental group, 27 control group) in early childhood education of A University located at Gyeonggi, Korea. The music creation activities using the application were conducted on the 10th week and the experimental research was carried out. Analysis of the difference between the experimental and control groups in the pre-test and post-test, showed a statistically significant effect on belief in musical teaching efficacy of the control group. The results showed that the teachers' positive attitude toward the role of teacher in the teacher education program using the application was positively influenced. The results of this study by taking advantage of new educational media of applications in teacher education and to provide a basis for exploring concrete action plans for utilizing the application in the teacher training curriculum for future educational.

• Journal of Embryo Transfer
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• v.12 no.3
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• pp.229-246
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• 1997

Implantation is a most important biological process during pregnancy whereby conceptus establishes its survival as well as maintenance of pregnancy. During the periimplantation period, both uterine endometriurn and conceptus synthesize and secrete a host of growth factors and cytokines which mediate the actions of estrogen and /or progesterone and also exert their steroid-independent actions. Growth factors expressed by the materno-conceptal unit en masse have important roles in cell migration, stimulation or inhibition of cell proliferation, cellular differentiation, maintenance of pregnancy and materno-conceptal communications in an autorcrine /paracrine manner. The present review focuses on the role of the intrauterine IGF system during periimplantation conceptus development. The IGF system comprises of IGF- I and IGF- II ligands, types I and II IGF receptors and six or more IGF-binding proteins(IGFBPs). IGFs and IGFBPs are expressed and secreted by uterine endometrium with tissue, pregnancy stage and species specificities under the influence of estrogen, progesterone and other growth factor(s). Conceptus also synthesizes components of the IGF system beginning from a period between 2-cell and blastocyst stages. Maternal IGFs are utilized by both maternal and conceptal tissues; conceptus-derived growth factors are believed to be taken up primarily by conceptus. IGFs enhance the development of both maternal and conceptal compartments in a wide range of biological processes. They stimulate proliferation and differentiation of endometrial cells and placental precursor cells including decidual transformation from stromal cells, placental formation and the synthesis of some steroid and protein hormones by differentiated endometrial cells or placenta. It is also well-documented in a number of experimental settings that both IGFs stimulate preimplantation embryo development. In slight contrast to these, prenatal mice carrying a null mutation of IGF and /or IGF receptor gene do not exhibit any apparent growth retardation until after implantation. Reason (s) for this discrepancy between the knock-out result and the in vitro ones, however, is not known. IGFBPs, in general, are believed to inhibit IGF action within the materno-conceptal unit, thereby allowing endometrial stromal cell differentiation as well as dampening ex cessive placental invasion into maternal tissue. There is evidence, however, indicating that IGFBP can enhance IGF action depending on environrnental conditions perhaps by directioning IGF ligand to the target cell. There is also a third possibility that certain IGFBPs and their proteolytic fragments may have their own biological activities independent of the IGF. In addition to IGFBPs, IGFBP proteases including those found within the uterine tissue or lumen are thought to enhance IGF bioavailability by degrading their substrates without affecting their bound ligand. In this regard, preliminary results in early pregnant pigs suggest that a partially characterized IGFBP protease activity in uterine luminal fluid enhances intrauterine IGF bioavailability during conceptus morphological development. In summary, a number of in vitro results indicate that IGFs stimulates the development of the rnaterno-conceptal unit during the periimplantation period. IGFBPs appear to inhibit IGF action by sequestering their ligands, whereas IGFBP proteases are thought to enhance intrauterine bioavailability of IGFs. Much is remaining to be clarified, however, regarding the roles of the individual IGF system components. These include in vivo evidence for the role of IGFs in early conceptus development, identification of IGF-regulated genes and their functions, specific roles for individual IGFBPs, identification and characterization of IGFBP proteases. The intrauterine IGF club house thus will be paying a lot of attention to forthcoming results in above and other areas, with its door wide-open!

• KOREAN JOURNAL OF CROP SCIENCE
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• v.30 no.2
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• pp.131-139
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• 1985

Breeders have concerned with the nature of gene action controlling the duration of grain filling period to combine early maturity and acceptable grain yield to fit wheat into multiple cropping systems. The 4 x 4 complete diallel set of F$_1$, F$_2$ and 1/2 (BC$_1$ + BC$_2$) in crosses of winter and spring wheat cultivars was made to determine the nature of gene action involved for duration of grain filling period. Using the Jinks-Hayman model, no maternal effects were noted nor were any non-allelic interactions observed for total duration of grain filling and lag period. The actual grain filling period was influenced to some degree by such interactions. The spring cultivars Red Bobs and Siete Cerros also appeared to have more dominant genes for longer total duration of grain filling and lag period. In contrast, the winter parents Yamhill and Hyslop had more dominant genes for the longer actual grain filling period. The genes appeared to be independently distributed among the parents.

• Plant Resources
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• v.4 no.3
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• pp.161-170
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• 2001

A major portion of drugs used in Ayurvedic system of medicine which has been practiced since the early human civilization in Indian subcontinent were of plant origin. It should be noted that 70% of the population in this region depends on Ayurveda for their medical treatment and 60% of the drug resources are obtained from the Himalayan region. Therefore, Nepal becomes a potential source of plant drug resource since it occupies a major portion of the Himalaya. In the present paper, in general a current status of medicinal plant resources of Himalayan region especially Nepal will be discussed. In addition to this, a typical example of antidiabetic activity of Shilajit will be taken for the discussion. Shilajit is one of the crucial elements in several formulations including those of Rasayana, a therapy in Ayurveda, which has been practiced in the prevention of ageing and mental disorder. Although, Shilajit is widely used for the treatment of diabetes, no satisfactory scientific reports are available up to now. The crude Shilajit in the market is a dark brown or black rock-like substance collected from the Himalayan region with a strong smell of cow's stale urine. In our studies, Shilajit (collected in the central Himalayan region) prevented the diabetes in nonobese diabetic (NOD) mice model. Shilajit also prevented the diabetes in the rats against the action of multiple low-dose (10 mg/kg, i.v., 5 times) of streptozotocin. On the other hand, Shilajit did not show antioxidative activity. The preventive action of Shilajit on diabetes is mainly focused on the Thl and Th2 cell activities, since Th2 cells activity was found to be significantly upregulated. Shilajit, however, showed a mild action in controlling the blood sugar level in young, old, and mild diabetic rats, but not in the severe diabetic rats. It also stimulated the nitric oxide production in macrophages. Based on these evidences, the antidiabetic activities of Shilajit appear to be immunomodulative probably by protecting or strengthening insulin-producing b-cells in the pancreas. Further systematic research on constituents of Shilajit and its quality evaluation is necessary to enable the use of natural medicines in the treatment of diabetes.

• The Journal of Korean Medicine
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• v.16 no.2 s.30
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• pp.100-114
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• 1995

This bibliographic study was designed to research indications of the Moschus which was representatively used for resuscitation in acute stage of stroke throughout successive books of oriental medicine. Especially, in this study, severe cases with disturbance of consciousness and acute stage of stroke were investigated. The results were summarized as the followings: 1. The Moschus was dried material which secreted from aromatic vescicle of Moschus moschiferus L.. which was pungent in flavor, warm in nature, nontoxic and strongly aromatic. The Moschus removed the obstruction in the channels and used to early stage of stroke. 2. The Moschus was aromatic resuscitatable medicine, which recovered disturbance of consciousness due to stroke. 3. The Moschus had excitatory actions of respirtory center and vascular motor center, heart stimulating action, inhibitatory action of the platelet aggregation and anti thrombin action and recovered cerebral ischemic change. According to these actions, the Moschus could be used cerebral infarction. 4. Prescriptions included the Moschus was used to symptoms of unconsciousness, secretion, stuporous mental state, dysarthria, facial palsy and hemiplegia. That was Angungwoohwangh wan(安宮牛黃丸), Woohwangchungshimwon(牛黃淸心元), Sahyangsohaphangwon(麝香蘇合香元), etc. According to the above mentioned results, the Moschus was aromatic resuscitatable medicine which was used for symptoms of conscius disturbance, convulsion, sudden fainting etc., promoted cerebral blood flow and had good effect on acute stage of stroke and severe cases with conscious disturbance. Therefore, it is considered that the Moschus must be studied for effect of cerebral infarction and hemorrhage in clinic with animal's and pharmacological experimental results.