• Wind and Structures
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• v.14 no.5
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• pp.383-411
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• 2011

Roof is an integral part of building envelope. It protects occupants from environmental forces such as wind, rain, snow and others. Among those environmental forces, wind is a major factor that can cause structural roof damages. Roof due to wind actions can exhibit either flexible or rigid system responses. At present, a dynamic test procedure available is CSA A123.21-04 for the wind uplift resistance evaluation of flexible membrane-roofing systems and there is no dynamic test procedure available in North America for wind uplift resistance evaluation of rigid membrane-roofing system. In order to incorporate rigid membrane-roofing systems into the CSA A123.21-04 testing procedure, this paper presents the development of a load cycle. For this process, the present study compared the wind performance of rigid systems with the flexible systems. Analysis of the pressure time histories data using probability distribution function and power spectral density verified that these two roofs types exhibit different system responses under wind forces. Rain flow counting method was applied on the wind tunnel time histories data. Calculated wind load cycles were compared with the existing load cycle of CSA A123.21-04. With the input from the roof manufacturers and roofing associations, the developed load cycles had been generalized and extended to evaluate the ultimate wind uplift resistance capacity of rigid roofs. This new knowledge is integrated into the new edition of CSA A123.21-10 so that the standard can be used to evaluate wind uplift resistance capacity of membrane roofing systems.

• The Journal of Internal Korean Medicine
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• v.27 no.1
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• pp.149-165
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• 2006

Objectives: This study was done to evaluate the effects of Saengkankunbi-tang on cell-viability, proliferation, cell-cycle, apoptosis and DNA replication on HepG2 cell and to find out by which molecular-biological mechanism by which Saengkankunbi-tang operates. Methods : The MTT assay, cell counting assay, [3H]-thymidine incorporation assay, flow cytometric analysis, tryphan blue exclusion assay, western blot analysis, quantative RT-PCR were taken. Results : Saengkankunbi-tang had no effect on proliferation, cell-cycle and DNA replications of HepG2 cells, while it improved cell viability and reduced apoptosis, and it activated Akt and NFKB. But, it did not produce an effect on cell viability and apoptosis when P13K/Akt pathway was blocked by LY294002 nor when $NF{\kapa}B$ activation was blocked by DN-$I{\kapa}B$. Conclusion : These results suggests that Saengkankunbi-tang improves cell viability and reduces apoptosis of HepG2 cells, by activating $NF{\kapa}B$ through PI3K/Akt pathway.

• Korean Journal of Animal Reproduction
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• v.20 no.2
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• pp.143-153
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• 1996

To improve the efficiency of nuclear transplantation in the rabbit, this study were evaluated the influence of celly cycle of donor nuclei on the in vitro developmental potential in the nuclear transplant embryos. The embryos of 16-cell stage were collected from the mated does at 48h post-hCG injection and they were synchronized to G1 phase of 32-cell stage. Synchronization of the cell cylce of blastomeres were induced, first, using an microtubules polymerization inhibitor, 0.5$\mu\textrm{g}$/ml colcemid for 10h to arrest blastomeres in metaphase, and secondly, using a DNA synthesis inhibitor, 0.1$\mu\textrm{g}$/ml aphidicolin for 1.5 to 2h to cleave to 32-cell stage and arrest them in G1 phase. The separated G1 phase blastomeres of 32-cell stage were injectied into enucleated recipient cytoplasms by micromanipulation. After culture until 20h post-hCG injection, the nuclear transplant oocytes were electrofused and activated by electrical stimulation. The nuclear transplant embryos were co-cultured for 120h. In vitro cultured embryos were monitored every 24h to assess for development rate. After in vitro cultue for 120h, the nuclear transplant embryos developed to blastocyst stage were stained with Hoechst 33342 dye for counting the number of blastomeres under a fluorescence microscopy. The cleavage rate of blastomeres from 16-cell stage stage rabbit embryos treated with colcemid for 10h or aphidicolin for 6h following colcemid for 10h were not significantly different. The electrofusion rate was similar by high in S and G1 phase donor nuclei as 80.6 and 79.1%, respectively. However, the nuclear transplant embryos using G1 phase donor nuclei were developed to blastocyst at high rate(60.3%) than those using S phase donor nuclei(26.0%). Moreover, the mean blastocyst stage were increased significantly(P<0.05) with the G1 phase donor nuclei(176.6 cells and 1.50 cycles), as compared with the S phase donor nuclei(136.6 cells and 1.42 cycles). These results show that the blastomeres of G1 phase were more successful as donor nuclei in the nuclear transplant procedure, compared with S phase.

• Journal of Physiology & Pathology in Korean Medicine
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• v.17 no.3
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• pp.819-825
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• 2003

pharbitis nil and Taraxacum mongolicum are representative herbs that have been used for cancer treatment in Korean traditional medicine. To understand the molecular basis of the antitumor function, we analyzed the effect of these herbs on proliferation and apoptosis of tumor cells using a gastric cancer cell line AGS. Cell counting assay showed that pharbitis nil strongly inhibit cell proliferation Of AGS whereas Taraxacum mongolicum exhibit no detectable effect on cellular growth. [³H]thymidine uptake analysis also demonstrated that DNA replication of AGS is suppressed in a dose-dependent manner by treatment with pharbitis nil. Additionally, tryphan blue exclusion assay showed that Pharbitis nil induce apoptotic cell death of AGS in a dose-dependent. To explore whether anti antiproliferative and/or proapototic property of Pharbitis nil is associated with their effect on gene expression, we performed RT-PCR analysis of cell cycle- and apoptosis-related genes. Interestingly, mRNA expression levels of c-Jun, c-Fos, c-Myc, and Cyclin D1 were markedly reduced by Pharbitis nil. Taraxacum mongolicum also showed inhibitory action on expression of these growth-promoting protooncogene but there effects are less significant, as compared to Pharbitis nil. Furthermore, it was also found that Pharbitis nil activates expression of the p53 tumor suppressor and its downstream effector p21Waf1, which induce G1 cell cycle arrest and apoptosis. Collectively, our data demonstrate that Pharbitis nil induce growth inhibition and apoptosis of human gastric cancer cells and these effects are accompanied with down-and up-regulation of growth-regulating protooncogenes and tumor suppressor genes, respectively. This observation thus suggests that the anticancer effect of Pharbitis nil might be associated with its regulatory capability of tumor-related gene expression.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.29 no.9 s.240
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• pp.1235-1242
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• 2005

A district heating(DH) system supplies environmentally-friend heat and is appropriate for reduction of energy consumption and/or air pollutions. The DH transmission pipe, composed of supply and return pipes, has been used to transmit the heat and prevent heat loss during transportation. The two types of pipes are operated at a temperature of $75\~115^{\circ}C\;and\;40\~65^{\circ}C$, respectively, with an operating pressure of less than 1.568MPa. The objectives of this paper are to systematize data processing of transition temperature and investigate its effects on fatigue life of DH pipes. For the sake of this, about 5 millions temperature data were measured during one year at ten locations, and then available fatigue lift estimation schemes were examined and applied to quantify the specific thermal fatigue life of each pipe. As a result, a relational database management system as well as reliable fatigue lift evaluation procedures is established for Korean DH pipes. Also, since the prototypal evaluation results satisfied both cycle-based and stress-based fatigue criteria, those can be used as useful information in the future fer optimal design, operation and energy saving via setting of efficient condition and stabilization of water temperature.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.14
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• pp.5667-5672
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• 2014

Folate receptor alpha ($FR{\alpha}$) mediates folate uptake by endocytosis, and while folate is essential to DNA methylation and synthesis and may have an important role in proliferating cells. $FR{\alpha}$ is known to be expressed in rapidly proliferating cells, including many cancer cell lines, but there has been no systematic assessment of expression in cervical cancer cell lines. The aim of the present study was to evaluate the effects of $FR{\alpha}$ on proliferation and apoptosis of cervical cells and correlation mechanism. In this study, we investigated the biological function of $FR{\alpha}$ in Hela cells using RNA interference. Cell proliferation was evaluated by Cell Counting Kit-8 (CCK8) assay, while cell cycling and apoptosis were assessed by flow cytometry, mRNA levels by real time-PCR and protein levels of $FR{\alpha}$, c-Fos and c-Jun by Western blotting. The results revealed that $FR{\alpha}$ was highly expressed in Hela cells and its silencing with a small interfering RNA (siRNA) inhibited cell proliferation and induced cell apoptosis, arresting the cell cycle in G0/G1 stages while decreasing the proportion in S and G2/M stages, and suppressed the expression levels of c-Fos and c-Jun. In conclusion, the results of this study indicated that $FR{\alpha}$ down-regulation might be capable of suppressing cervical cancer cell proliferation and promoting apoptosis. It suggested that $FR{\alpha}$ might be a novel therapeutic target for cervical cancer.

• Transactions of the Korean Society of Pressure Vessels and Piping
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• v.13 no.2
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• pp.1-18
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• 2017

Metal fatigue is an important aging mechanism that material characteristics can be deteriorated when even a small load is applied repeatedly. An accurate fatigue evaluation is very important for component structural integrity and reliability. In the design stage of a nuclear power plant, the fatigue evaluations of the Class 1 components have to be performed. However, operating experience shows that the design evaluation can be very conservative due to conservatism in the transient severity and number of occurrence. Therefore, the fatigue monitoring system has been considered as a practical mean to ensure safe operation of the nuclear power plants. The fatigue monitoring system can quantify accumulated fatigue damage up to date for various plant conditions. The purpose of this paper is to describe the fatigue monitoring procedure and to introduce the fatigue monitoring program developed by the authors. The feasibility of the fatigue monitoring program is demonstrated by comparing with the actual operating data and finite element analysis results.

• BMB Reports
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• v.48 no.10
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• pp.583-588
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• 2015

Microtubule actin crosslinking factor 1 (MACF1), a widely expressed cytoskeletal linker, plays important roles in various cells by regulating cytoskeleton dynamics. However, its role in osteoblastic cells is not well understood. Based on our previous findings that the association of MACF1 with F-actin and microtubules in osteoblast-like cells was altered under magnetic force conditions, here, by adopting a stable MACF1-knockdown MC3T3-E1 osteoblastic cell line, we found that MACF1 knockdown induced large cells with a binuclear/multinuclear structure. Further, immunofluorescence staining showed disorganization of F-actin and microtubules in MACF1-knockdown cells. Cell counting revealed significant decrease of cell proliferation and cell cycle analysis showed an S phase cell cycle arrest in MACF1-knockdown cells. Moreover and interestingly, MACF1 knockdown showed a potential effect on cellular MTT reduction activity and mitochondrial content, suggesting an impact on cellular metabolic activity. These results together indicate an important role of MACF1 in regulating osteoblastic cell morphology and function.

• Korean Journal of Agricultural Science
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• v.49 no.2
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• pp.269-284
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• 2022

The development of radish collectors has the potential to increase radish yields while decreasing the time and dependence on human labor in a variety of field activities. Stress and fatigue analyses are essential to ensure the optimal design and machine life of any agricultural machinery. The objectives of this research were to analyze the stress and fatigue of major components of a tractor-mounted radish collector under dynamic load conditions in an effort to increase the design dependability and dimensions of the materials. An experiment was conducted to measure the shaft torque of stem-cutting and transferring conveyor motors using rotary torque sensors at different tractor ground speeds with and without a load. The Smith-Watson-Topper mean stress equation and the rain-flow counting technique were utilized to determine the required shear stress with the distribution of the fatigue life cycle. The severity of the operation was assessed using Miner's theory. All running conditions produced more than 10⁷ of high cycle fatigue strength. Furthermore, the highest severity levels for motor shafts used for stem cutting and transferring and for transportation joints and cutting blades were 2.20, 4.24, 2.07, and 1.07, and 1.97, 3.81, 1.73, and 1.07, respectively, with and without a load condition, except for 5.24 for a winch motor shaft under a load. The stress and fatigue analysis presented in this study can aid in the selection of the most appropriate design parameters and material sizes for the successful construction of a tractor-mounted radish collector, which is currently under development.

• Journal of Microbiology and Biotechnology
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• v.33 no.4
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• pp.449-462
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• 2023

Previously, we confirmed that Mychonastes sp. 246 methanolic extract (ME) markedly reduced the viability of BxPC-3 human pancreatic cancer cells. However, the underlying mechanism ME remained unclear. Hence, we attempted to elucidate the anticancer effect of ME on BxPC-3 human pancreatic cancer cells. First, we investigated the components of ME and their cytotoxicity in normal cells. Then, we confirmed the G1 phase arrest mediated growth inhibitory effect of ME using a cell counting assay and cell cycle analysis. Moreover, we found that the migration-inhibitory effect of ME using a Transwell migration assay. Through RNA sequencing, Gene Ontology-based network analysis, and western blotting, we explored the intracellular mechanisms of ME in BxPC-3 cells. ME modulated the intracellular energy metabolism-related pathway by altering the mRNA levels of IGFBP3 and PPARGC1A in BxPC-3 cells and reduced PI3K and mTOR phosphorylation by upregulating IGFBP3 and 4E-BP1 expression. Finally, we verified that ME reduced the growth of three-dimensional (3D) pancreatic cancer spheroids. Our study demonstrates that ME suppresses pancreatic cancer proliferation through the IGFBP3-PI3K-mTOR signaling pathway. This is the first study on the anticancer effect of the ME against pancreatic cancer, suggesting therapeutic possibilities and the underlying mechanism of ME action.