• Proceedings of the KIEE Conference
• /
• 2001.07d
• /
• pp.2166-2168
• /
• 2001

Reactor Noise is defined as the fluctuations of measured instrumentation signals during full-power operation of reactor which have informations on reactor system dynamics such as neutron kinetics. The Reactor internal structures which consist of many complex components are subjected to flow-induced vibration due to high temperature and pressure in reactor coolant system. The above flow-induced vibration causes degradation of structural integrity of the reactor and may result in loosing mechanical binding component which might impact other equipment and component or cause flow blockage. It is important to analyze reactor noise signal for the early detection of potential problem or failure in order to diagnosis reactor integrity in the point of view of safety and plant economics. Detailed design of hardware diagnostic system reactor internal structures using neutron noise(RIDS).

• Proceedings of the Korean Environmental Sciences Society Conference
• /
• 2020.10a
• /
• pp.219-219
• /
• 2020

Kaempferol (3,4',5,7-tetrahydroxyflavone), a flavonoid found in beans, broccoli, garlic, etc., has been used in natural medicine as an anti-inflammatory and antioxidant. This experiment was carried out to evaluate the anti-apoptotic effect of kaempferol in 12-O-tetradecanoylphorbol 13-acetate (TPA)-treated Normal Human Dermal Fibroblast (NHDF). Kaempferol inhibited the production of intracellular Reactive Oxygen Species (ROS) induced by TPA in NHDF. Kaempferol significantly blocks the phosphorylation of extracellular signal-regulated kinase responsible for the activation of nuclear factor-kappa B. In addition, kaempferol significantly attenuated the expression of Bax and cleaved caspase-3 as regulated by the phosphorylation of nuclear factor-kappa B during its blockage of TPA-induced apoptotic cell death. These findings suggest that kaempferol protects the apoptotic signaling pathway induced by TPA through modulating intracellular ROS in NHDF.

• Journal of Applied Biological Chemistry
• /
• v.56 no.2
• /
• pp.61-67
• /
• 2013

Due to their diversity and abundancy, marine resources have emerged as important biological resources to compensate the limited sources of terrestrial biological materials. Phaeodactylum tricornutum (PT) is one of classical model diatoms most widely studied for its ecology, physiology, biochemistry and molecular biology. In this study, four different PT extracts on lipopolysaccharide (LPS)-stimulated macrophages were compared for anti-inflammatory effect and investigated for the underlying mechanisms. The extracts of PT inhibited nitric oxide production from LPS stimulated RAW 264.7 cells in a dose dependent manner. These extracts also inhibited the expression of mRNA and production of proteins of pro-inflammatory cytokines such as interleukin (IL)-$1{\beta}$, IL-6 and tumor necrosis factor-${\alpha}$. These inhibitory effects were found to be caused by blockage of nuclear factor-${\kappa}B$ activation and phosphorylation of p38 mitogen-activated protein kinases, extracellular signal-regulated kinases 1 and 2 and c-Jun N-terminal kinase.

• Asian Pacific Journal of Cancer Prevention
• /
• v.17 no.2
• /
• pp.667-671
• /
• 2016

Oridonin, an ent-kaurane diterpenoid compound isolated from the traditional Chinese herb Rabdosia rubescens, has shown various pharmacological and physiological effects such as anti-tumor, anti-bacterial, and anti-inflammatory properties. However, the effect of oridonin on human ovarian cancer cell lines has not been determined. In this study, we demonstrated that oridonin inhibited ovarian cancer cell proliferation, migration and invasion in a dose-dependent manner. Furthermore, we showed oridonin inhibited tumor growth of ovarian cancer cells (SKOV3) in vivo. We then assessed mechanisms and found that oridonin specifically abrogated the phosphorylation/activation of mTOR signaling. In summary, our results indicate that oridonin is a potential inhibitor of ovarian cancer by blocking the mTOR signaling pathway.

• Natural Product Sciences
• /
• v.15 no.1
• /
• pp.32-36
• /
• 2009

Glutamate causes neurotoxicity through formation of reactive oxygen species and activation of mitogen-activated protein kinase (MAPK) pathways. MAPK phosphatase-1 (MKP-1) is one of the phosphatases responsible for dephosphorylation/deactivation of three MAPK families: the extracellular signal-regulated kinase-1/2 (ERK-1/2), the c-Jun N-terminal kinase-1/2 (JNK-1/2), and the p38 MAPK. In this report, the potential involvement of MKP-1 in neuroprotective effects of curcumin, the active ingredient of turmeric (Curcuma longa), was examined using HT22 cells. Glutamate caused cell death and activation of ERK-1/2 but not p38 MAPK or JNK-1/2. Blockage of ERK-1/2 by its inhibitor protected HT22 cells against glutamate-induced toxicity. Curcumin attenuated glutamate-induced cell death and ERK-1/2 activation. Interestingly, curcumin induced MKP-1 activation. In HT22 cells transiently transfected with small interfering RNA against MKP-1, curcumin failed to inhibit glutamate-induced ERK-1/2 activation and to protect HT22 cells from glutamate-induced toxicity. These results suggest that curcumin can attenuate glutamate-induced neurotoxicity by activating MKP-1 which acts as the negative regulator of ERK-1/2. This novel pathway may contribute to and explain at least one of the neuroprotective actions of curcumin.

• KSBB Journal
• /
• v.11 no.2
• /
• pp.165-172
• /
• 1996

To obtain a correctly folded human proinsulin, export of proinsulin using Staphylococcal protein A signal sequence-mediated secretion pathway has been attempted in E.coli. A secretion operon for proinsulin was constructed by consecutively connecting T7 promoter, SPA ribosome binding site, SPA signal sequence gene, and human proinsulin gene. Little immunoreactive proinsulin was detected in the periplasmic space and. culture medium, and not even in cytoplasmic space. The qualitative analysis of transcribed proinsulin mRNA and the in vitro transcription/translation experiment suggests that the negligible level of proinsulin export appears to be due to intracellular degradation of proinsulin, rather than due to the blockage during translocation. However, expression of proinsulin fusion protein such as MBP-proinsulin could dramatically increase export of proinsulin in E.coli.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.18 no.9
• /
• pp.2298-2306
• /
• 2014

In this paper, we propose an open loop power control algorithm to control transmission power of the On-The-Move(OTM) Satcom terminal in GEO satellite communication environment. The proposed algorithm identifies the current channel state restricted by an obstacle or an antenna depointing loss based on the received beacon signal strength. On the basis of the determined signal attenuation causes, the OTM Satcom terminal turns off the RF output when an antenna tracking is failed. If the OTM Satcom terminal experiences a channel blockage by an obstacle, the terminal spreads the transmit data to increase data reception probability. To evaluate the performance of the proposed algorithm, we compare an adjacent satellite interference level and an outage probability. The results show the performance of the proposed algorithm is better than that of the conventional algorithm.

• Asian Pacific Journal of Cancer Prevention
• /
• v.15 no.1
• /
• pp.69-73
• /
• 2014

The effects of erlotinib combined with celecoxib in a lung cancer xenograft model were here explored with a focus on possible mechanisms. A xenotransplanted lung cancer model was established in nude mice using the human lung cancer cell A549 cell line and animals demonstrating tumour growth were randomly divided into four groups: control, erlotinib, celecoxib and combined (erotinib and celecoxib). The tumor major axis and short diameter were measured twice a week and after 40 days tissues were collected for immunohistochemical analyses of Bcl-2 and Bax positive cells and Western-blotting analyses for the epidermal growth factor recepto (EGFR), P-EGFR, and cyclooxygenase-2 (COX-2). Tumor size in the combined group was smaller than in the others (p<0.01) and the percentage of Bcl-2 positive cells was fewer in most cases (p<0.01), while that of Bax positive cells was greater than in the erlotinib and celecoxib groups (P>0.05). Western blotting showed decreased expression of P-EGFR and COX-2 with both erlotinib and celecoxib treatments, but most pronouncedly in the combined group (P<0.05). Simultaneous blockage of the EGFR and COX-2 signal pathways exerted stronger growth effects in our human xenotransplanted lung cancer model than inhibition of either pathway alone. The anti-tumor effects were accompanied by synergetic inhibition of tumor cell apoptosis, activation of p-EGFR and expression of COX-2.

• Journal of Positioning, Navigation, and Timing
• /
• v.1 no.1
• /
• pp.35-43
• /
• 2012

The UGV is one of the special field robot developed for mine detection, surveillance and transportation. To achieve successfully the missions of the UGV, the accurate and reliable navigation data should be provided. This paper presents design and implementation of multi-sensor-based open architecture integrated navigation for localization of UGV. The presented architecture hierarchically classifies the integrated system into four layers and data communications between layers are based on the distributed object oriented middleware. The navigation manager determines the navigation mode with the QoS information of each navigation sensor and the integrated filter performs the navigation mode-based data fusion in the filtering process. Also, all navigation variables including the filter parameters and QoS of navigation data can be modified in GUI and consequently, the user can operate the integrated navigation system more usefully. The conventional GPS/INS integrated system does not guarantee the long-term reliability of localization when GPS solution is not available by signal blockage and intentional jamming in outdoor environment. The presented integration algorithm, however, based on the adaptive federated filter structure with FDI algorithm can integrate effectively the output of multi-sensor such as 3D LADAR, vision, odometer, magnetic compass and zero velocity to enhance the accuracy of localization result in the case that GPS is unavailable. The field test was carried out with the UGV and the test results show that the presented integrated navigation system can provide more robust and accurate localization performance than the conventional GPS/INS integrated system in outdoor environments.

• Journal of the Korean Society for Aeronautical & Space Sciences
• /
• v.37 no.7
• /
• pp.678-684
• /
• 2009

Many researches on the GNSS integer ambiguity resolution methods for precise positioning and attitude determination applications have been done. However, by the time invariant property of the integer ambiguity, the reuse of integer ambiguity without performing time consuming integer search procedure is possible. In this paper, a new efficient integer ambiguity propagation method is proposed. The initial integer ambiguity can be determined using the famous LAMBDA method and it is propagated with the propagation method. The proposed method can reconfigure the integer ambiguity using the previous epoch's integer ambiguity and new carrier phase measurements under environmental variations such as geometry changes, signal blockage and reacquisition. Experiments with real measurements show the proposed method can determine an integer ambiguity effectively.