• BMB Reports
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• v.46 no.4
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• pp.219-224
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• 2013

The cell-fate specification of the anchor cell (AC) and a ventral uterine precursor cell (VU) in Caenorhabditis elegans is initiated by a stochastic interaction between LIN-12/Notch receptor and LAG-2/Delta ligand in two neighboring Z1.ppp and Z4.aaa cells. Both cells express lin-12 and lag-2 before specification, and a small difference in LIN-12 activity leads to the exclusive expressions of lin-12 in VU and lag-2 in the AC, through a feedback mechanism of unknown nature. Here we show that the expression pattern of lag-1/CSL, a transcriptional repressor itself that turns into an activator upon binding of the intracellular domain of Notch, overlaps with that of lin-12. Site-directed mutagenesis of LAG-1 binding sites in lag-1 maintains its expression in the AC, and eliminates it in the VU. Thus, AC/VU cell-fate specification appears to involve direct regulation of lag-1 expression by the LAG-1 protein, activating its transcription in VU cells, but repressing it in the AC.

• Geomechanics and Engineering
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• v.2 no.3
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• pp.213-227
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• 2010

Compacted layers of sand-bentonite mixtures have been proposed and used in a variety of geotechnical projects as engineered barriers for the enhancement of impervious landfill liners, cores of zoned earth dams and radioactive waste repository systems. This paper presents a study on the valorization of local materiel such as dune sand from Laghouat region and mine bentonite intended for the realization of liner base layers in the conception of insulation barriers for hazardous waste centers. In the practice we try to get an economical mixture that satisfies the hydraulic and mechanical properties specified by regulation rules. The effect of the bentonite additions on the mixture is reflected by its capability of clogging the matrix pores upon swelling. In order to get an adequate dune sand-bentonite mixture, an investigation on hydraulic and mechanical behaviours is carried out in this study for different mixtures. Using oedometer test, the adequate bentonite addition to the mixture, which satisfies the conditions on permeability, is found to be around 12% to 15%. These results are also confirmed by direct measurement using triaxial cell.

• International Commerce and Information Review
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• v.8 no.1
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• pp.125-141
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• 2006

It is no unnecessary to tell the importance of foreign trade in Korea economics. Nevertheless, government's direct support is impossible owing to WTO's regulation. Accordingly, government have brought focus into trade facilitation as paperless trade. e-Trade document repositary building by government's budget and private sector's cooperation is a part of e-Trade platform and necessary function in connection with relay and certification of e-Trade document. This study examined the estimated operational problems of e-Trade document repositary as compared Licensed Electronic Document Repositary. Firstly, the operator of e-Trade document repositary undertake multiple role and function as Licensed Certification Authorities(e-sign Act), Licensed Electronic Document Repositary(Framework Act on Electronic Transaction) etc. Secondly, sufficient levy that meet operating cost of the e-trade document is the key point of e-Trade document repositary's success, because additional budget invest in that operation is too hard to do. Thirdly, the operator of the e-Trade document repositary have to keep fairness, objectivity and transparency because the operational right is exclusive.

• Korean Journal of Occupational Health Nursing
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• v.14 no.1
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• pp.34-43
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• 2005

Purpose: The purpose of this study is to develop the curriculum model for occupational health nurse specialist in Korea. Method: Internet searching was conducted to analyze the type of master program for occupational health nurses in the U. S. To identify the importance of occupational health nurse specialist (OHNS)'s role, self-administrative questionnaire survey was done to335 occupational health nurses through postal mail and continuing education in 2003. SPSSWIN 10.0 was used for data analysis. Results: In the U. S., two main types of nurse practitioner program and nurse manager program are separately operated for occupational health nurses as master level. Under the governmental support, geographical and financial barrier can be decreased through the distance learning and the appointment of regional ERC. Most occupational health nurses recognized importantly the role of OHNS as direct care provider, educator, consultant, and manager. Conclusion: It is recommended that the job standard for OHNS needs to be developed, and regulation has to be changed for the diverse curriculum based on the need of occupational health nurses, and governmental support must be strengthened for occupational health nurses to apply more easily to the program.

• Molecules and Cells
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• v.39 no.4
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• pp.292-298
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• 2016

Aquaporin 1 (AQP1) is expressed in most microvasculature endothelial cells and forms water channels that play major roles in a variety of physiologic processes. This study aimed to delineate the transcriptional regulation of AQP1 by Mef2c in endothelial cells. Mef2c cooperated with Sp1 to activate human AQP1 transcription by binding to its proximal promoter in human umbilical cord vein endothelial cells (HUVEC). Over-expression of Mef2c, Sp1, or Mef2c/Sp1 increased HUVEC migration and tube-forming ability, which can be abolished AQP1 knockdown. These data indicate that AQP1 is a direct target of Mef2c in regulating angiogenesis and vasculogenesis of endothelial cells.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 1999.11a
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• pp.66-70
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• 1999

In this paper we explored a framework on technical regulations of telecommunication in UK. and pointed out essental element of thier success. After exploring the trend of UK, we also provide some policy suggestion on buiding of technical regulations of telecommunications in Korea

• Transactions of the Korean Society of Automotive Engineers
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• v.22 no.7
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• pp.98-106
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• 2014

Emission standards for passenger diesel engines are becoming more and more stringent. Especially, Europe started the regulation of nano-particles from 2011 with EURO 5b. The objective of this study is to investigate the effect of fuel injection strategy on combustion and nano-particle emission in a small diesel engine. In this study, we conducted combustion analysis and measured both the weight of PM and number of nano-particels. At first, the optimum injection timing was determined with fixed engine operating conditions, such as engine speed, load, and fuel injection quantity. After that, the injection timing was controlled, and the effect of pilot injection was investigated. The number of nano-particles increased as engine load decreases, and it increased up to 10 times depending on the change of injection timing. The weight of PM emissions was increased at low load, and the PM emissions increased with increasing the number of pilot injections.

• Journal of Electrical Engineering and Technology
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• v.13 no.3
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• pp.1265-1274
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• 2018

This paper proposes a virtual flux (VF) and positive-sequence power based control strategy to improve the performance of grid-interfaced three-phase voltage source converters against unbalanced and distorted grid conditions. By using a second-order generalized integrator (SOGI) based VF observer, the proposed strategy achieves an AC voltage sensorless and grid frequency adaptive control. Aiming to realize a balanced sinusoidal line current operation, the fundamental positive-sequence component based instantaneous power is utilized as the control variable. Moreover, the fundamental negative-sequence VF feedforward and the harmonic attenuation ability of a sequence component generator are employed to further enhance the unbalance regulation ability and the harmonic tolerance of line currents, respectively. Finally, the proposed scheme is completed by combining the foregoing two elements with a predictive direct power control (PDPC). In order to verify the feasibility and validity of the proposed SOGI-VFPDPC, the scenarios of unbalanced voltage dip, higher harmonic distortion and grid frequency deviation are investigated in simulation and experimental studies. The corresponding results demonstrate that the proposed strategy ensures a balanced sinusoidal line current operation with excellent steady-state and transient behaviors under general grid conditions.

• Journal of Electrical Engineering and Technology
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• v.13 no.3
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• pp.1060-1068
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• 2018

Droop control schemes have been widely employed in the control strategies for Multi-Terminal Direct Current (MTDC) system for its high reliability. Under the conventional DC voltage-active power droop control, the droop slope applies a proportional relationship between DC voltage error and active power error for power sharing. Due to the existence of DC network impedance and renewable resource fluctuation, there is inevitably a DC voltage deviation from the droop characteristic, which in turn results in inaccurate control of converter's power. To tackle this issue, a piecewise droop control with DC voltage dead band or active power dead band is implemented into controller design. Besides, an advanced droop control scheme with versatile function is proposed, which enables the converter to regulate DC voltage and AC voltage, control active and reactive power, get participated into frequency control, and feed passive network. The effectiveness of the proposed control method has been verified by simulation results.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.19 no.1
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• pp.1-12
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• 2015

This paper discusses current internet interconnection issues according to radical changes of internet traffic pattern. In this context, the recovery of network investment cost for network provider becomes hot issue. For recovery issues of investment cost, there are many disputes among stake holders. Therefore, it is necessary to investigate this issues in the context of internet interconnection. Also, it is important to develop the current regulation about internet interconnection under traffic changing environments. This paper selects four issues to deal with and analyzes the present situations and problems about these issues, and provides alternatives for internet interconnection corresponding to these four issues.