• Title/Summary/Keyword: Formation Factors

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Effects of Nutritional and Environmental Conditions on Planktonic Growth and Biofilm Formation of Citrobacter werkmanii BF-6

  • Zhou, Gang;Li, Long-Jie;Shi, Qing-Shan;Ouyang, You-Sheng;Chen, Yi-Ben;Hu, Wen-Feng
    • Journal of Microbiology and Biotechnology
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    • v.23 no.12
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    • pp.1673-1682
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    • 2013
  • Citrobacter sp. is a cause of significant opportunistic nosocomial infection and is frequently found in human and animal feces, soil, and sewage water, and even in industrial waste or putrefaction. Biofilm formation is an important virulence trait of Citrobacter sp. pathogens but the process and characteristics of this formation are unclear. Therefore, we employed in vitro assays to study the nutritional and environmental parameters that might influence biofilm formation of C. werkmanii BF-6 using 96-well microtiter plates. In addition, we detected the relative transcript levels of biofilm formation genes by RT-PCR. Our results indicated that the capacity of C. werkmanii BF-6 to form biofilms was affected by culture temperature, media, time, pH, and the osmotic agents glucose, sucrose, NaCl, and KCl. Confocal laser scanning microscopy results illustrated that the structure of biofilms and extracellular polysaccharide was influenced by 100 mM NaCl or 100 mM KCl. In addition, nine biofilm formation genes (bsmA, bssR, bssS, csgD, csgE, csgF, mrkA, mrkB, and mrkE) were found to contribute to planktonic and biofilm growth. Our data suggest that biofilm formation by C. werkmanii BF-6 is affected by nutritional and environmental factors, which could pave the way to the prevention and elimination of biofilm formation using proper strategies.

A Study for Formation Principles of Dynamic Connection Structure between Stocks in Korean Stock Market (주식간 동적 연결구조의 형성원칙에 관한 연구)

  • Kim, Seung-Hwan;Lee, Un-Cheol;Um, Cheol-Jun
    • The Korean Journal of Financial Management
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    • v.21 no.1
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    • pp.183-204
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    • 2004
  • This paper introduces an observable connection structure between stocks in Korean stock market and investigates the formation principles of the observed connection structure between stocks in economic views. Several recent studies have been attempting to explain that the connection structure between stocks is organized by Power-Law distribution, this implies that most stocks have a few links, but only a few stocks have very large number of links. Therefore, we want to investigate the reason about why the connection structure between stocks exhibited by Mantegna's approach is Power-Law distribution. As a result we found that the number of connection between stocks is determined by market factors and specific firm factors among many other factors. In addition, if a stock is more affected by common factors(market) than specific firm factors, the stock has large number of links with other stocks, otherwise more affected by specific firm factors, the stock has a few links.

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Microstructure and Mechanical Properties of Hardmaterials

  • Hayashi, Koji
    • Proceedings of the Korean Powder Metallurgy Institute Conference
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    • 1994.04c
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    • pp.6-6
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    • 1994
  • Har dmaterials such as cemented carbides with or without coated layer, cermets, ceramics and diamond or c-BN high pressure sintered compact are used for cutting tools, wear -resistant parts, rock drilling bits and/or high pressure vessels. These hardmaterials contain not only hard phase, but also second consituent as the element for forming ductile phase and/or sintering aid, and the mechanical properties of each material depend on (1) the amount of the second constituent as well as (2) the grain size of the hard phase. The hardness of each material mainly depends on these two factors. The fracture strength, however, largely depends on other microstructur a1 factors as well as the above two factors. For all hardmaterials, the fracture strength is consider ably affected by (3) the size of microstructur a1 defect which acts as the fracture source. In cemented carbides, the following factors which are generated mainly due to the addition of the second constituent are also important; (4) the variation of the carbon content in the normal phase region free from V-phase and graphite phase, (5) the precipitation of $Co_3$ during heating at about $800^{\circ}C$,(6) the domain size of binder phase, and (7) the formation of ${\beta}$-free layer or Co-rich layer near the surface of sintered compacts. For cemented carbides coated with thin hard substance, the important factors are as follows; (8) the kind of coated substance, (9) the formation of ${\eta}$-phase layer at the interface between coated layer and substrate, (10) the type of residual stress (tension or compression) in the coated layer which depends on the kind of coating method (CVD or PVD), and (11) the properties of the substrate, and (12) the combination, coherency and periodicity of multi-layers. In the lecture, the details of these factors and their effect on the strength will be explained.

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The Effect of Sleeve and Skirt Width . Length Variation of Dress on Impression Formation (원피스드레스의 소매와 스커트폭.길이변화가 인상형성에 미치는 영향)

  • 이웅희;강경자
    • Journal of the Korean Society of Clothing and Textiles
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    • v.21 no.6
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    • pp.1060-1071
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    • 1997
  • The purpose of this study is to identify the effect of clothing cues(sleeve and skirt width, length) on female impressions. The experimental materials developed for this study are a set of stimuli and response scales. The stimuli are 16 pictures manipulated with sleeve and skirt width · length variations by computer drawing. The experimental design consists of 3 factorial design: (1) sleeve shapes(plain, upper expanded, below expanded, all expanded) (2) skirt width (wide, narrow) (3) skirt length(long, short) The 7-point semantic differential response scale designed for visual evaluation of female' s impression formation on sleeve shape and skirt width · length is 27 bipolar adjectives. The results of this study are as follows: 1. When we analize the impressions of female figure by sleeve shape and width · length of skirt, it becomes clear that maturity, modernity, attention, elegance and tenderness are proved to be important. Among these five factors, maturity, modernity and attention are identified as more important ones. 2. Sleeve shape have an effect on all factors except maturity and the effects of sleeve on the four factors are not striking. ' Width of skirt are most influential to the maturity and attention, but it does not have any effect on modernity. However two factor, that is width of skirt and sleeve have an effects on modernity, attention and tenderness. ' The length of skirt has an effects on the tenderness, elegance and modernity, but it dose not have any effect on attention. But width and length of skirt have an effects on attention, tenderness and modernity The length of skirt and sleeve have an effect on tenderness.

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Understanding the formation mechanism of SNS addiction and its prevention strategy (SNS 사용자 중독 형성 매커니즘과 중독 예방 전략)

  • Kim, Byoungsoo
    • The Journal of Information Systems
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    • v.28 no.4
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    • pp.27-47
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    • 2019
  • Purpose The study examined the key factors influencing the formation mechanism of SNS addiction. Based on the use and gratification theory, we considered relationship maintenance, perceived enjoyment, and self-expression as main desires to induce SNS addiction. The characteristics of SNS users were also considered as major factors affecting SNS addiction. In particular, self-control and subjective well-beings were considered to be prevention factors that could reduce SNS addiction, while SNS relational intimacy was considered to be a facilitator that would increase SNS addiction. Design/Methodology/Approach A structural equation modeling (SEM) method was used to test the theoretical framework based on a sample of 224 Facebook users who have used it more than 6 months. Confirmation factor analysis was conducted to check the reliability, convergent validity, and discriminant validity. Findings Relationship maintenance had a significant effect on self-disclosure intention and SNS addiction, respectively. Perceived enjoyment was significantly related to self-disclosure intention, while it was insignificantly associated with SNS addiction. However, self-expression was not significantly related to both self-disclosure intention and SNS addiction. Consistent with our expectations, both self-control and subjective well-beings had negative effects on SNS addiction. The analysis results found that SNS relational intimacy was positively related to SNS addiction.