• Journal of Microbiology
• /
• v.42 no.2
• /
• pp.69-73
• /
• 2004

Vibrio vulnificus, a Gram-negative bacterium found in estuarine waters, is responsible for over 95％ of all seafood-related deaths in the United States. As a result of a temperature downshift to 5$^{\circ}C$, this organism enters the viable but nonculturable (VBNC) state. Changes in the membrane fatty acid (FA) composition of V. vulnificus may be a contributing factor to the ability of this organism to enter into and survive in the VBNC state. This hypothesis was tested by incubating the organism at 5$^{\circ}C$ in arti-ficial sea water and analyzing the cells' FAs during the initial hours of temperature and nutrient down-shift. Prior to downshift, the predominant FAs were 16:0, 16:1 and 18:0. During the first four hours of downshift, statistically significant changes occurred in 15:0, 16:1, 16:0, 17:0, and 18:0. These results indicate that changes in FA composition occur prior to entry of V. vulnificus into the VBNC state, suggesting that the ability to maintain membrane fluidity may be a factor in this physiological response. Cells in which fatty acid synthesis was inhibited did not survive, indicating that active fatty acid metab-olism is essential for entry of cells into the VBNC state.

• Journal of Microbiology
• /
• v.42 no.2
• /
• pp.74-79
• /
• 2004

Ingestion of shellfish-associated Vibrio parahaemolyticus is the primary cause of potentially severe gas-troenteritis in many countries. However, only Kanagawa phenomenon (hemolysin) positive (KP$\^$+/) strains of V. parahaemolyticus are isolated from patients, whereas >99％ of strains isolated from the environment do not produce this hemolysin (i.e. are KP$\^$-/). The reasons for these differences are not known. Following a temperature downshift, Vibrio parahaemolyticus enters the viable but noncultur-able (VBNC) state wherein cells maintain viability but cannot be cultured on routine microbiological media. We speculated that KP$\^$+/ and KP$\^$-/ strains may respond differently to the temperature and salinity conditions of seawater by entering into this state which might account for the low numbers of cul-turable KP$\^$+/ strains isolated from estuarine waters. The response of eleven KP$\^$+/ and KP$\^$-/ strains of V. parahaemolyticus following exposure to a nutrient and temperature downshift in different salinities, similar to conditions encountered in their environment, was examined. The strains included those from which the KP$\^$+/ genes had been selectively removed or added. Our results indicated that the ability to produce hemolysin did not affect entrance into the VBNC state. Further, VBNC cells of both biotypes could be restored to the culturable state following an overnight temperature upshift.

• Journal of Construction Engineering and Project Management
• /
• v.8 no.1
• /
• pp.1-9
• /
• 2018

US transportation agencies are dealing with shrinking budgets, limited work forces, and deteriorating infrastructure. In order to cope with funding uncertainty, state highway agencies are now looking into their own organizations and identifying programs, practices, and processes that have potential for cost saving. A quality assurance (QA) program is an integral part of highway construction and ensures a project's contracted level of quality. The cost of quality (conforming and nonconforming) can constitute a sizable part of total construction cost. As the quality assurance programs evolved, various practices and processes were developed over time and later adopted by state highway agencies. These practices and processes include different QA standards and specifications, varying testing methods, central testing lab vs. on site testing, performance based vs. prescribed quality assurance practices, implementation of innovative quality assurance practices, etc. Therefore, there is an opportunity to assess different QA strategies and recommend those practices that are effective and cost efficient. A national survey was conducted by the authors, which provided a detailed mapping of various QA practices and processes used as part of QA programs and identified areas where agencies can focus on for cost savings. The survey found that QA sampling and testing plans, optimization of sampling plans, optimization of QA standards and specifications, and implementation of innovative test methods and processes are the main areas the agencies should focus to lean the current QA programs.

• KIEE International Transactions on Electrophysics and Applications
• /
• v.5C no.6
• /
• pp.264-269
• /
• 2005

The electrostatic comb drive actuator is one of the main building blocks in the field of micro electro-mechanical systems (MEMS). Most of the comb actuators presented previously have fingers that are rectangular in shape which produce a stable, constant force output during actuation. The use of sawtooth fixed fingers in a comb drive, which were presumed to produce an increasing force output with displacement due to the increased number of regions where fringing force, the driving force of comb actuators, appear. The dimensions of the sawtooth were derived from finite element analysis (FEA) of simplified finger models with sawtooth type fingers of various dimension and were compared to the rectangular finger model that showed that the sawtooth type fingers have $7\~9$ times stronger driving force. Finally, comb drive actuators with sawtooth type and rectangular fingers were fabricated and although the gap was bigger, the comb actuator with sawtooth type fingers showed about 1.7 times greater electrostatic force than the one with rectangular fingers at equal driving voltages. In conclusion, using the proposed sawtooth type comb fingers in a comb drive makes it possible to increase its displacement or reduce the driving voltage.

• Journal of the Korean Data and Information Science Society
• /
• v.25 no.3
• /
• pp.493-499
• /
• 2014

The Pythagorean won-loss formula postulated by James (1980) indicates the percentage of games as a function of runs scored and runs allowed. Several hundred articles have explored variations which improve RMSE by original formula and their fit to empirical data. This paper considers a variation on the formula which allows for variation of the Pythagorean exponent. We provide the most suitable optimal exponent in the Pythagorean method. We compare it with other methods, such as the Pythagenport by Davenport and Woolner, and the Pythagenpat by Smyth and Patriot. Finally, our results suggest that proposed method is superior to other tractable alternatives under criterion of RMSE.

• Journal of Microbiology and Biotechnology
• /
• v.16 no.4
• /
• pp.543-549
• /
• 2006

DNA microarray was used to study the transcription profiling of Escherichia coli adapting to acetate as a sole carbon source. Bacteria grown in glucose minimal media were used as a reference. The dynamic expression levels of 3,497 genes were monitored at seven time points during this adaptation. Among the central metabolic genes, the glycolytic and glucose phosphotransferase genes were repressed as the bacteria entered stationary phase, whereas the glyoxylate pathway, TCA cycle, and gluconeogenic genes were induced. Distinct induction or repression patterns were recognized among different pathway genes. For example, the repression of glycolytic genes and the induction of gluconeogenic ones started immediately after glucose was depleted. On the other hand, the regulation of the pentose phosphate pathway genes and glyoxylate genes gradually responded to the glucose depletion or was more related to growth in acetate. When the whole genome was considered, many of the CRP, FadR, and Cra regulons were immediately responsive to the glucose depletion, whereas the $\sigma^s$, Lrp, and IHF regulons were gradually responsive to the glucose depletion. The expression profiling also provided differential regulations between isoenzymes; for example, malic enzymes A (sfcA) and B (maeB). The expression profiles of three genes were confirmed with RT-PCR.

• Advances in Energy Research
• /
• v.1 no.2
• /
• pp.117-126
• /
• 2013

In this paper, core-shell semiconductor quantum dots (QDs) CdSeS/ZnS with emission at 490 nm and 450 nm were investigated for their use in luminescent down-shifting (LDS) layers. Luminescent quantum yield (LQY) of the QDs measurements in solution proposed that they were suitable candidates for inclusion in LDS layers. QDs were encapsulated in poly(methyl,methacrylate) (PMMA) polymer matrix and films were fabricated of $134{\pm}0.05$ microns. Selections of organic dyes from BASF Lumogen F range were also investigated for their use as LDS layers; Violet 570 and Yellow 083. The addition of LDS layers containing Violet 570 dye demonstrated a unity LQY when encapsulated within a PMMA matrix. A PV device of an LDS layer of Lumogen Violet 570 deposited on top of a crystalline silicon cell was fabricated where it was demonstrated to increase the efficiency of the cell by 34.5% relative.

• Journal of the Korean Institute of Landscape Architecture
• /
• v.23 no.1
• /
• pp.189-214
• /
• 1995

본 연구는 미국의 건축 및 조경공간 형성에 미친 일본문화를 파악하기 위한 기초연구로서, 일본문화 및 공간디자인의 특성과 미국건축 및 조경에 나타난 그 면모에 관한 것이다. 1853년 미국과 일본의 문화교류를 시작으로 일본의 예술과 건축이 미국에 소개되었고, 특히 1893년 Chicago에서 열렸던 Wor1ds Columbian Exposition에서 선보인 일본의 건축물은 당시 미국의 건축가들에게 영향을 주었다. 그후 일본의 공간디인은 건축뿐만 아니라 조경분야에도 영향을 미쳐 현재 미국의 공간디자인을 구성하고 있는 특성 가운데 하나로 자리잡고 있다. 필자는 미국의 공간디자인에 영향을 준 일본문화의 실재를 파악하기 위하여 한국과 중국의 문화와 구별되는 일본만의 독특한 문화적 특성을 고찰해보고, 미국 현대건축의 선구자인 Frank Lloyd Wright, Greece and Greene, Philip Johnson, Richard J. Neutra의 작품 및 조경디자이너인 Ethelbert E. Furlong, James C. Rose의 작품속에 나타난 일본식 공간디자인의 면모를 살펴보았다. 장래 이 분야의 연구에서는 미국문화의 특성이 고찰되어 미국과 일본의 두 문화가 비교 파악되기 위한 개념적 근거가 마련되고, 일본식 공간디자인이 미국에서 어떻게 이해되고 해석되어졌으며 미국식 공간 디자인으로 전환되었는지 살펴보며, 어떤 이유에서 일본의 공간디자인 양식이 미국의 건축 및 조경분야에서 문화적으로 일본보다 오랜 역사를 지닌 한국과 중국의 공간디자인 양식보다 커다란 영향을 주고 있는지에 관해 이해를 구하는 방향으로 연구가 수행되어야 함을 제안한다.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2001.11a
• /
• pp.141-144
• /
• 2001

An accurate cross sections set are necessary for the quantitatively understanding and modeling of plasma phenomena. By using the electron swarm method, we determine an accurate electron cross sections set for objective atoms or molecule at low electron energy range. In previous paper, we calculated the electron transport coefficients in pure CF$_4$ molecular gas by using two-term approximation of the Boltzmann equation. And by using this simulation method, we confirmed erroneous calculated results of transport coefficients for CF$_4$ molecule treated in this paper having 'C2v symmetry'as C$_3$H$_{8}$ and C$_3$F$_{8}$ which have large vibrational excitation cross sections which may exceed elastic momentum transfer cross section. Therefore, in this paper, we calculated the electron transport coefficients(W and ND$_{L}$) in pure CF$_4$ gas by using multi-term approximation of the Boltzmann equation by Robson and Ness which was developed at James-Cook university, and discussed an application and/or validity of the calculation method by comparing the calculated results by two-term and multi-term approximation code.e.

• The Transactions of the Korea Information Processing Society
• /
• v.6 no.5
• /
• pp.1241-1252
• /
• 1999

It is proposed in TINA, the open information telecommunication network architecture, that the definition of object group which is collection of objects provides a decrease of complex networking and a facility of object managing by service executing of application on distributed computing environment. Based on a new distributed object group model[13] we have been researched according to TINA specification, this paper proposed the object group model with the scheduler object and objects management mechanisms that can support real-time services on CORBA. To do this, we described the definition of object grouping and the requirements to suggest the object group model supporting real-time service, designed the object group structure and functional components containing in an object group using James Rumbaugh's modelling[12], and showed a class diagram of components in an object group. This paper designed IDLs of an object group manager and scheduler among the components, and finally showed the procedures of management and service interconnections between objects in the different object groups vi ETD.