Structural and Biochemical Studies Reveal a Putative FtsZ Recognition Site on the Z-ring Stabilizer ZapD

Hyungho Lee,Hwajung Choi,민경진,Bunzo Mikami,윤혜진 한국분자세포생물학회 2016 Molecules and cells Vol.39 No.11

FtsZ, a tubulin homologue, is an essential protein of the Z-ring assembly in bacterial cell division. It consists of two domains, the N-terminal and C-terminal core domains, and has a conserved C-terminal tail region. Lateral interactions between FtsZ protofilaments and several Z-ring associated proteins (Zaps) are necessary for modulating Z-ring formation. ZapD, one of the positive regulators of Z-ring assembly, directly binds to the C-terminal tail of FtsZ and promotes stable Z-ring formation during cytokinesis. To gain structural and functional insights into how ZapD interacts with the C-terminal tail of FtsZ, we solved two crystal structures of ZapD proteins from Salmonella typhimurium (StZapD) and Escherichia coli (EcZapD) at a 2.6 and 3.1 Å resolution, respectively. Several conserved residues are clustered on the concave sides of the StZapD and EcZapD dimers, the suggested FtsZ binding site. Modeled structures of EcZapD-EcFtsZ and subsequent binding studies using bio-layer interferometry also iden-tified the EcFtsZ binding site on EcZapD. The structural insights and the results of bio-layer interferometry assays suggest that the two FtsZ binding sites of ZapD dimer might be responsible for the binding of ZapD dimer to two protofilaments to hold them together.

Energy Prices and Risk Exposure To The Budget of Korean Households

Hyungho Youn,Byung In Lim,Eui Young Lee,YoungRok Choi 인하대학교 정석물류통상연구원 2009 인하대학교 정석물류통상연구원 학술대회 Vol.2009 No.10

The abrupt increase in the energy prices in 2007 and 2008 impinged economic hardship on a low income Korean household. Especially it caused a low income household to spend more on energy out of total budget as well as prevented it from buying energy enough for living. Consequently, our household economy faces risk associated with energy prices. There are established government policies such as unemployment insurance and various subsidy plans to help households in poverty. However there are no public measures that alleviate their financial difficulty when a low income household is squeezed by high energy prices. The purpose of this study is to see how high energy prices influence Korean households and how seriously they cause risk to household economy. We develop a risk measure by employing variance of ratios of energy expenditure to current income. Then we use the risk measure to see how differently high energy prices generate risk across expenditure segments during energy prices hike. Also we use it to shed a light on how diverse income brackets are exposed to risk. We find energy experienced an increase in risk faster than other expenditures. Also we notice that a low income household faced the same result compared to upper income households. Base on these findings, we recommend additional energy subsidy be provided to a low income family automatically if energy price index rises above a certain level. The measure will mitigate energy risk the society faces.

Wireless LAN with Medical-Grade QoS for E-Healthcare

Hyungho Lee,박경준,Young-Bae Ko,최종호 한국통신학회 2011 Journal of communications and networks Vol.13 No.2

In this paper, we study the problem of how to design a medical-grade wireless local area network (WLAN) for healthcare facilities. First, unlike the IEEE 802.11e MAC, which categorizes traffic primarily by their delay constraints, we prioritize medical applications according to their medical urgency. Second,we propose a mechanism that can guarantee absolute priority to each traffic category, which is critical for medical-grade quality of service (QoS), while the conventional 802.11e MAC only provides relative priority to each traffic category. Based on absolute priority,we focus on the performance of real-time patient monitoring applications, and derive the optimal contention window size that can significantly improve the throughput performance. Finally, for proper performance evaluation from a medical viewpoint, we introduce the weighted diagnostic distortion (WDD) as a medical QoS metric to effectively measure the medical diagnosability by extracting the main diagnostic features of medical signal. Our simulation result shows that the proposed mechanism, together with medical categorization using absolute priority, can significantly improve the medical-grade QoS performance over the conventional IEEE 802.11e MAC.

ULTRASIM<SUP>R</SUP> Integrative Simulation Technology on the Development of Automotive Plastic Parts

HyungHo Jae,Zeidam Rachib de Matos,Minoug Kim,Stefan Glaser,Andreas Wuest 한국소음진동공학회 2012 한국소음진동공학회 학술대회논문집 Vol.2012 No.4

To enhance the CAE accuracy, the definition of material behavior is one of key influence on the result. In case of plastic material with fiber reinforcement, the anisotropic material behavior should be taken into account to increase of CAE accuracy. BASF has developed an innovative CAE tool, ULTRASIM<SUP>R</SUP>, which is capable of generating material models of thermoplastic materials for structural simulation. ULTRASIM<SUP>R</SUP>, not only the glass fiber orientation effect, but also the weld line effect, tensile-compression anisotropy, strain rate effect are combined in a non-linear material law, which will be evaluated in a unique failure criterion, thus resulting in an highly accurate CAE approach.

Differential Effects of Negative Publicity on Beef Consumption according to Household Characteristics

Hyungho Youn,Byung In Lim,Hyun Joung Jin 한국유통학회 2012 한국유통학회 학술대회 발표논문집 Vol.2012 No.6

Output Diffusion of the Monopolist over Time and Space

Hyungho Youn,Patrick De Leenheer,Victor Tremblay 한국재정학회 2015 한국재정학회 학술대회 논문집 Vol.2015 No.3

In this paper, we develop an output diffusion model in which a monopoly firm faces a cost of adjusting output over time and across geographic regions. First, we investigate a dynamic monopoly model and a simple spatial model with only regional adjustment costs. Then, we explore how the firm maximizes profits over time and space, a problem of calculus of variation. The Euler equation yields a partial differential equation, the output diffusion model. It extends the traditional inter-temporal output path into output diffusion over time and space. As long as regional adjustment costs exist, steady-state output in the diffusion model is less than the static monopoly output level. This model suggests that a policy designed to lower regional adjustment costs can increase supply in all geographic regions.

The Effect of Price Upsurge on Energy Expenditure Ratio

Hyungho Youn,Byung-In Lim 한국재정학회(구 한국재정·공공경제학회) 2009 한국재정학회 학술대회 논문집 Vol.2009 No.3

The purpose of this study is to see how energy price upsurge in 2008 affects energy expenditure ratio by income group. We develop a theoretical model to show that the ratio moves inversely with income while together with price. From these theoretical results, we infer that a low income household falls into energy poverty if prices rise abruptly. In fact, we can observe such an event in Korea in 2008. Next, we test the theoretical results by building an empirical model. The empirical results coincide with theoretical ones.

Analysis of Participation by Female Seniors in the Korean Job Creation Program for the Elderly

Hyungho Youn,Jin Su Hwang 숙명여자대학교 아시아여성연구원 2010 Asian Women Vol.26 No.1

The high aging rate in Korea is unprecedented in the history of the nation. However, the public system for supporting old people financially is insufficient. As a way of coping with rapid aging, the government of Korea launched a job creation program for the elderly in 2004. Five years after its inception, it has now taken the position as a full-scale public labor project. The previous researches on the program were mainly concerned with two issues from gender-neutral perspective, building a system of the program and evaluating its performance. Their findings are also limited as they used the surveys of small sample size collected at a particular time and location, and their methodology relied mainly on subjective opinions by the program participants. The present research is based on more reliable and comprehensive data for empirical analysis and investigates socio-economic conditions of the participants, their participation motives, work types, and also their participation frequency a from gender perspective. Female participants were less educated, economically weak, and lived alone. Because of their disadvantaged socio-economic status, they were more likely to choose public service over education in work type. Also, they tended to participate repeatedly in the program to earn income rather than for self-development or social participation. Considering the behavior of female participants, we would suggest that the program be redesigned to fortify income function so that females who have participated for longer periods can be benefited with higher wages and extended work days.

Differential Effects of Negative Publicity on Beef Consumption according to Household Characteristics in South Korea

Hyungho Youn,Byung-In Lim,Hyun-Jung Jin 한국재정학회 2012 한국재정학회 학술대회 논문집 Vol.2012 No.춘계

This paper examines how South Korean households responded to an unprecedented boycott campaign against US beef from spring through summer of 2008, and investigates differential responses in relation to households' characteristics. It was found that beef consumption reduced by 4.8% immediately after the so-called candle-light demonstration. Instead, pork and chicken consumption increased by 17.2% and 16.6%, respectively. This confirms a substitution effect due to the negative publicity concerning US beef. It also was found that the negative publicity effect was transitory and the reactions of consumers were not uniform; they differed depending on their socio-economic characteristics. The econometric model revealed that younger, less-educated, and/or lower-income households were more susceptible to the negative publicity, and reduced their beef consumption more than other households.

Multibody approach for tolerance analysis andoptimization of mechanical systems

Hyungho Chun,권상직,Taeoh Tak 대한기계학회 2008 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.22 No.2

A multibody approach is suitable for tolerance analysis of mechanical systems since multibody formulation can directly consider part-level tolerance variables. In this study, procedures for performing tolerance analysis and corresponding sensitivity analysis for spatial multibody systems are proposed. First, statistical formulation for performing multibody system tolerance analysis is developed to obtain system level tolerance for given part-level tolerances. One very useful aspect of the proposed formulation is that in the process of computing system tolerance, the sensitivity of system tolerance with respect to part-level tolerances can be additionally obtained. The kinematics of spatial multibody systems has been redefined in terms of both generalized coordinates and part-level tolerance variables. Tolerances in geometry of a body are specified in terms of the variations in relative locations of joint definition points and relative distance between them. Tolerances in the joint kinematics are defined through variations in vector closure equations and orthogonality equations that are two fundamental constraint equations for most kinematic joints. To demonstrate the validity and effectiveness of the proposed tolerance analysis procedure, tolerance analysis of a spatial 4-bar mechanism and tolerance optimization are performed.