• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.44 no.3
• /
• pp.216-224
• /
• 2011

Capsosiphon fulvescens is well-known green sea algae that, in recent years, has been proposed as a potential anticancer drug. In this study, we found that C. fulvescens glycoprotein (Cf-GP) had pro-apoptotic effects on human gastric carcinoma cells. By SDS-PAGE, we confirmed that C. fulvescens extract contained a glycoprotein. Using H33342 staining, we found that the Cf-GP caused cell death in a does-dependent manner, while an MTS assay showed decreased cellular viability due to induction of apoptosis. To determine the effect of Cf-GP on apoptosis-related cellular events, cells were treated with Cf-GP and the expression of several apoptosis-related protein was determined by Western blotting. Our results indicate that Cf-GP activated both a caspase cascade and PARP, which is a substrate of caspase-3, caspase-8 and the Bcl-2 family proteins. In addition, we assessed caspase-3, and -8 activation and annexin V staining. Our results revealed a cell cycle arrest, itself leading to an increased percentage of sub-G1 cells. Our findings indicate that Cf-GP may be a source of bio-functional material with therapeutic effects on human gastrointestinal cancer.

• The Transactions of the Korean Institute of Electrical Engineers B
• /
• v.55 no.8
• /
• pp.416-422
• /
• 2006

With the increasing demand for renewable energy, distributed power included in fuel cells have been studied and developed as a future energy source. For this system, a power conversion circuit is necessary to interface the generated power to the utility. In many cases, a high step-up dc/dc converter is needed to boost low input voltage to high voltage output. Conventional methods using cascade dc/dc converters cause extra complexity and higher cost. The conventional topologies to get high output voltage use flyback dc/dc converters. They have the leakage components that cause stress and loss of energy that results in low efficiency. This paper presents a high boost converter with a voltage multiplier and a coupled inductor. The secondary voltage of the coupled inductor is rectified using a voltage multiplier and series-connected with the boost voltage of primary voltage of the coupled inductor. Therefore, high boost voltage is obtained with low duty cycle. Theoretical analysis and experimental results verify the proposed solutions using a 300W prototype.

• JSTS:Journal of Semiconductor Technology and Science
• /
• v.14 no.6
• /
• pp.760-767
• /
• 2014

This paper describes a high-radix crossbar switch design with low latency and power dissipation for Network-on-Chip (NoC) applications. The reduction in latency and power is achieved by employing a folded-clos topology, implementing the switch organized as three stages of low-radix switches connected in cascade. In addition, to facilitate the uniform placement of wires among the sub-switch stages, this paper proposes a Mux-Matrix-Mux structure, which implements the first and third switch stages as multiplexer-based crossbars and the second stage as a matrix-type crossbar. The proposed 256-radix, 8-bit crossbar switch designed in a 65nm CMOS has the simulated power dissipation of 1.92-W and worst-case propagation delay of 0.991-ns while operating at 1.2-V supply and 500-MHz frequency. Compared with the state-of-the-art designs in literature, the proposed crossbar switch achieves the best energy-delay-area efficiency of $0.73-fJ/cycle{\cdot}ns{\cdot}{\lambda}^2$.

• Journal of the Society of Naval Architects of Korea
• /
• v.55 no.5
• /
• pp.415-420
• /
• 2018

The development of sail gas has increased the production of ethane as well as natural gas. The decline in the market price for ethane has led to a change in the petroleum-based ethylene production process into an ethane-based ethylene production process and an increase in the ethane/ethylene trade volume. Large-scale ethane/ethylene carrier have been needed due to an increase in long-distance trade from the US, and cargo type change have leaded to consider a liquefaction process to re-liquefy Boil-Off gas generated during the voyage. In this paper, the liquefaction system of Liquefied Ethane Gas carrier was evaluated with Low-GWP (Low-Global Warming Potential) refrigerant and process parameters, Boil-Off Gas pressure and expansion valve outlet pressure, were optimized. Low-GWP refrigerants were propane (R290), propylene(R1270), carbon dioxide(R744) was considered at two type of liquefaction process such as Linde and cascade cycle. The results show that the optimal pressure point depends on the individual refrigerant and the highest liquefaction efficiency of carbon dioxide (R744) - propane (R290) refrigerant.

• Journal of Life Science
• /
• v.25 no.5
• /
• pp.607-614
• /
• 2015

Cancers are the largest cause of mortality and morbidity all over the world. Cordycepin, an adenosine analog, is a major functional component of the Cordyceps species, which has been widely used in traditional Oriental medicine. Over the last decade, this compound has been reported to possess many pharmacological properties, such as an ability to enhance immune function, as well as anti-inflammatory, antioxidant and anti-cancer effects. Recently, numerous studies have reported interesting properties of cordycepin as a chemopreventive agent as well. There is an accumulating body of experimental evidences suggesting that cordycepin impedes cancer progression by promoting apoptosis, inducing cell cycle arrest, modulating intracellular signaling pathways, and inhibiting invasion and metastasis of cancer cells. In many cancer cell lines, cordycepin inhibits growth and cell cycle progression by inducing arrest of the G2/M phase, resulting from the inhibition of retinoblastoma protein phosphorylation and induction of cyclin-dependent kinase inhibitors. To induce apoptosis, cordycepin activates the extrinsic and intrinsic pathways, which promotes reactive oxygen species generation and the downstream activation of kinase cascades. Cordycepin also can activate alternative pathways to cell death such autophagy. In addition, cordycepin can inhibit the pro-metastatic processes of cancer cell detachment, migration, and invasion through a variety of mechanisms, including the nuclear factor-kappa B and activated protein-1 signaling pathways. In this review, we summarized the variety of action mechanisms by which cordycepin may mediate chemopreventive effects on cancer and discussed the potential of this natural product as a promising therapeutic inhibitor of cancer development.

• The Journal of the Institute of Internet, Broadcasting and Communication
• /
• v.11 no.4
• /
• pp.147-156
• /
• 2011

Though a dozen of different software life cycle models are suggested, there is no universal model which can satisfy all the characteristics of software. Organizations mix and match different life cycle models to develop a model more tailored for their systems and capabilities. We suggest overlapped-concurrent development life cycle model that is more suitable in various software development environment. Firstly, we divided the development process into abstract and implementation stage. Abstract stage is from software concept phase to detailed design starting time, and implementation stage is from detailed design phase to system testing phase. Next, the abstract stage introduced the overlapped phase concept that begins the next phase when the step is completed 20% by applying pareto's law. In the implementation stage, we introduced the concurrent development which the several phases are performed some time as when one use-case (UC) is completed the next development phase is started immediately. The proposed model has an advantage that it can reduce the inefficiency of development resource greatly. This model can increase the customer satisfaction with a great product at a low cost and on a short schedule. Also, this model can contribute to increase the software development success rate.

• Herbal Formula Science
• /
• v.15 no.2
• /
• pp.127-137
• /
• 2007

The purpose of this study was to investigate the effect of Yong-dam-sa-gan-tang (YST) on apoptosis in HepG2 cells, First of all. to study the cytotoxic effect of methanol extract of YST on HepG2 cells, the cells were treated with various concentrations of YST and then cell viability was determined by XTT reduction method and trypan blue exclusion assay. YST reduced proliferation of HepG2 cells in a dose-dependent manner. To confirm the induction of apoptosis, HepG2 cells were treated with various concentrations of YST. The cleavage of poly AD P-ribose polymerase (P ARP), a substrate for caspase-3 and a typical sign of apoptosis, and the activation of caspase-3, procaspase-8 and procaspase-8 were examined by western blot analysis. YST decreased procaspase-3, procaspase-8 and procaspase-9 levels in a dose-dependent manner and induced the clevage of PARP. YST triggered the mitochondrial apoptotic signaling by increasing the release of cytochrome c from mitochondria to cytosol. Furthermore, YST also downregulated the anti-apoptotic Bcl-2 and upregulated the pro-apoptotic-Bax. Therefore, this result suggest that YST induced HepG2 cell death through the mitochondrial pathway. Sustained activation of the Ras/Raf/MEK/ERK cascade in cells results in a cell cycle arrest and has been implicated in the differentiation of certain cell types, in many cases acting to promote differentiation. YST decreased the activation of Ras/Raf/MEK/ERK cascade in a dose-dependent manner. These results suggest that YST is potentially useful as a chemo-therapeutic agent in HepG2.

• Proceedings of the Korea Water Resources Association Conference
• /
• 2015.05a
• /
• pp.231-231
• /
• 2015

Rapid development in the upper reaches of the Mekong River, in the form of construction of large hydropower dams and reservoirs, large irrigation schemes, and rapid urban development, is putting water resources under stress. Many scientific reports have pointed out that cascade dams along the Mekong River lead to serious problems: not only hydrologically but also a decline of agricultural productivity due to a decrease of sediment supply in the Mekong Delta and a change of fish amount due to drastic change of the water environment. Cambodia and Vietnam, located in the lowest Mekong basin, are gravely affected by radical changes of hydrologic regime due to Mekong River developments. In particular, the Tonle Sap Lake in Cambodia is very sensitive to the flood cycle and flow variation of the Mekong River as well as inflow water quality from the Mekong River. More than 50% of Cambodian GDP depends on the primary industries such as agriculture, fishing, and forestry, and the Tonle Sap Lake plays an important role to support the national economy in Cambodia. In addition, Cambodian people usually take nourishment from the fish of Tonle Sap Lake. This research aims to assess the impacts of the Mekong river flow alternation on the hydrologic regime of the Mekong River - Tonle Sap Lake. We carried out rainfall-runoff-inundation simulation using CAESER-LISFLOOD for integrated water resource management in the Tonle Sap Basin and then analyze flood inundation variation of the Tonle Sap Lake due to the scenarios. Furthermore, the simulated inundation maps were compared to MODIS satellite images for model verification and hydrologic prediction.

• BMB Reports
• /
• v.54 no.10
• /
• pp.516-521
• /
• 2021

Although arginase primarily participates in the last reaction of the urea cycle, we have previously demonstrated that arginase II is an important cytosolic calcium regulator through spermine production in a p32-dependent manner. Here, we demonstrated that rhaponticin (RPT) is a novel medicinal-plant arginase inhibitor and investigated its mechanism of action on Ca²⁺-dependent endothelial nitric oxide synthase (eNOS) activation. RPT was uncompetitively inhibited for both arginases I and II prepared from mouse liver and kidney. It also inhibited arginase activity in both aorta and human umbilical vein endothelial cells (HUVECs). Using both microscope and FACS analyses, RPT treatments induced increases in cytosolic Ca²⁺ levels using Fluo-4 AM as a calcium indicator. Increased cytosolic Ca²⁺ elicited the phosphorylations of both CaMKII and eNOS Ser1177 in a time-dependent manner. RPT incubations also increased intracellular L-arginine (L-Arg) levels and activated the CaMKII/AMPK/Akt/eNOS signaling cascade in HUVECs. Treatment of L-Arg and ABH, arginase inhibitor, increased intracellular Ca²⁺ concentrations and activated CaMKII-dependent eNOS activation in ECs of WT mice, but, the effects were not observed in ECs of inositol triphosphate receptor type 1 knockout (IP3R1^-/-) mice. In the aortic endothelium of WT mice, RPT also augmented nitric oxide (NO) production and attenuated reactive oxygen species (ROS) generation. In a vascular tension assay using RPT-treated aortic tissue, cumulative vasorelaxant responses to acetylcholine (Ach) were enhanced, and phenylephrine (PE)-dependent vasoconstrictive responses were retarded, although sodium nitroprusside and KCl responses were not different. In this study, we present a novel mechanism for RPT, as an arginase inhibitor, to increase cytosolic Ca²⁺ concentration in a L-Arg-dependent manner and enhance endothelial function through eNOS activation.

• The Korean Journal of Physiology and Pharmacology
• /
• v.26 no.5
• /
• pp.367-375
• /
• 2022

Gastric cancer stem cells (GCSCs) are a major cause of radioresistance and chemoresistance in gastric cancer (GC). Therefore, targeting GCSCs is regarded as a powerful strategy for the effective treatment of GC. Atorvastatin is a widely prescribed cholesterol-lowering drug that inhibits 3-hydroxy-3-methylglutaryl-coenzyme A reductase, a rate-limiting enzyme in the mevalonate pathway. The anticancer activity of atorvastatin, a repurposed drug, is being investigated; however, its therapeutic effect and molecular mechanism of action against GCSCs remain unknown. In this study, we evaluated the anticancer effects of atorvastatin on MKN45-derived GCSCs. Atorvastatin significantly inhibited the proliferative and tumorsphere-forming abilities of MKN45 GCSCs in a mevalonate pathway-independent manner. Atorvastatin induced cell cycle arrest at the G0/G1 phase and promoted apoptosis by activating the caspase cascade. Furthermore, atorvastatin exerted an antiproliferative effect against MKN45 GCSCs by inhibiting the expression of cancer stemness markers, such as CD133, CD44, integrin α6, aldehyde dehydrogenase 1A1, Oct4, Sox2, and Nanog, through the downregulation of β-catenin, signal transducer and activator of transcription 3, and protein kinase B activities. Additionally, the combined treatment of atorvastatin and sorafenib, a multi-kinase targeted anticancer drug, synergistically suppressed not only the proliferation and tumorsphere formation of MKN45 GCSCs but also the in vivo tumor growth in a chick chorioallantoic membrane model implanted with MKN45 GCSCs. These findings suggest that atorvastatin can therapeutically eliminate GCSCs.