• Title/Summary/Keyword: Disruption

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Site-specific Disruption of Glyoxylate Bypass and Its Effect in Lysine-producing Corynebacterium lactofermentum Strain

  • Kim, Youn-Hee;Lee, Heung-Shick
    • Journal of Microbiology and Biotechnology
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    • v.6 no.5
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    • pp.315-320
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    • 1996
  • The role of glyoxylate bypass in a lysine-producing Corynebacterium lactofermentum strain was analyzed. Unlike the wild type, the strain expressed enzymes of glyoxylate bypass during growth in the fermentation broth containing glucose as the carbon source. To evaluate the importance of glyoxylate bypass in the strain, we disrupted chromosomal aceA by using a cloned fragment of the gene. Site-specific disruption of aceA which codes for the isocitrate lyase, the first enzyme of the bypass, was confirmed by Southern blot analysis. The aceA mutant strain completely lost isocitrate lyase activity and ability to grow in a minimal medium containing acetate as the sole carbon source. The mutant strain was similar to its parental strain in growth characteristics and produced comparable amounts of lysine in shake flasks containing glucose as the carbon source. The amount of oxaloacetate accumulated in the fermentation medium was similar for both strains, suggesting that expression of glyoxylate bypass does not necessarily lead to the increase in intracellular oxaloacetate. These data clearly demonstrate that glyoxylate bypass does not function as one of the routes of carbon supply for lysine production in the strain. It appears that the leakiness of the glyoxylate bypass in the strain might be the result of a secondary mutation which arose during previous strain development by random mutagenesis.

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A Seamless Handover Scheme for High-Speed Trains using Dual Mobile Routers (고속철도 환경에서 이중 이동 라우터를 이용한 끊김없는 핸드오버 방안)

  • Park Hee-Dong;Kwon Yong-Ha;Lee Kang-Won;Lee Sung-Hyub;Cho You-Ze;Yoon Yong-Ki
    • Journal of KIISE:Information Networking
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    • v.33 no.3
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    • pp.269-276
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    • 2006
  • This paper proposes a seamless handover scheme for high-speed trains using dual mobile routers to minimize service disruption time and packet loss during handovers. In the proposed scheme, each of the dual mobile routers is located at each end of the moving network for space diversity. One of the two mobile routers can continuously receive packets from its home agent, while the other is undergoing a handover, but they act as one logical mobile router. Analytical and simulation results showed that the proposed scheme could provide no service disruption or packet losses during handovers.

Custody Transfer of Bundle layer in Security Mechanism for Under water Inter net of Things (UIoT)

  • Urunov, Khamdamboy;Namgung, Jung-Il;Park, Soo-Hyun
    • Journal of Korea Multimedia Society
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    • v.18 no.4
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    • pp.506-523
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    • 2015
  • The intent is to determine whether or not the custody transfer is helpful for data transmission in challenging underwater communications when running Bundle protocol or underwater protocols. From the point of view defending side, Underwater Acoustic Network (UAN) will be a serious threat for its strong functionality long rang and high precision of surveillance and detection. Therefore, countermeasures must be taken to weaken its effect. Our purpose is analyzed that how to benefit from the UIoT to learn from, exploit and preserve the natural underwater resources. Delay/Disruption Tolerant Network (DTN) is essential part of the network heterogeneity communication network. The vulnerability and potential security factors of UIoT are studied thereafter. Security mechanisms for an underwater environment are difficult to apply owing to the limited bandwidth. Therefore, for underwater security, appropriate security mechanisms and security requirements must be defined simultaneously. The paper consists of mathematical and security model. Most important point of view in the security challenges of effective Buffer and Storage management in DTN.

Effects of Pride and Shame on Interactive Peer Play of Young Children: Focusing on the Mediating Effects of Their Daily Stress (유아의 자부심과 수치심이 또래놀이행동에 미치는 영향: 일상적 스트레스의 매개효과를 중심으로)

  • Choi, Song Yi;Shin, Nary
    • Korean Journal of Childcare and Education
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    • v.13 no.1
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    • pp.107-124
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    • 2017
  • Objectives: The purpose of this study was to investigate the effects of children's pride and shame on their interactive peer play, mediated by their daily stress. Methods: The participants of this study were 172 five-year-old children (80 boys and 92 girls) attending kindergartens or child-care centers in Chungbuk, Korea. The data were analyzed by descriptive and correlational analyses, and structural equation modeling using SPSS 19.0 and AMOS 21.0. Results: Children's shame had a significant indirect effect on their interactive peer play, including play-disruption, play-disconnection and play-interactions, mediated by daily stress; children's shame had a significant direct effect on play interaction. However, children's pride did not have a direct effect on daily stress and an indirect effect on their interactive peer play. In other words, high levels of shame among children led to high perceived daily stress. In turn, perceived daily stress increased play-disconnection and play-disruption, while it decreased play-interactions. Meanwhile children's shame led to a low level of play-interaction among young children. Conclusion/Implications: The results imply that children's perceived shame would influence their behaviors in social contexts as well as their psychological wellbeing such as the level of daily stress.

Relationships between Preschoolers' Negative Emotionality and Peer Play Behaviors by the Mediation of Behavioral Problems: Focusing on Gender Difference (유아의 부정적 정서성과 또래놀이행동 간 관계에서 행동문제의 매개적 역할: 성차를 중심으로)

  • Sung, Miyoung
    • Korean Journal of Childcare and Education
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    • v.13 no.3
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    • pp.1-17
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    • 2017
  • Objective: The purpose of this study was to analyze the effects of preschoolers' negative emotionality on their peer play behaviors, focusing on the mediation of behavioral problems. Methods: The study sample included 287 preschoolers aged 3 to 5 attending child care centers located in Seoul, Korea. The instruments used in this study were the Child Behavior Questionnaires (CBQ), Child Behavior Checklist (CBCL), and Penn Interactive Peer Play Scale (PIPPS). Results: The main results of this study are as follows: First, boys and girls' negative emotionality exerted positive effects on their behavioral problems. Second, boys and girls' negative emotionality had a positive influence on their play interaction, play disruption, and play disconnection. Further, the effect of boys' negative emotionality on their play disruption and play disconnection was totally mediated by their behavioral problems, and girls' negative emotionality on their play interaction and play disconnection was totally mediated by their behavioral problems. Conclusion/Implications: These findings provide preliminary evidence that the relationships between preschoolers' negative emotionality and peer play behaviors may be mediated by their behavioral problems.

Sleep and Anger (수면과 분노)

  • Seo, Yumin;Kim, Seog Ju
    • Sleep Medicine and Psychophysiology
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    • v.26 no.2
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    • pp.67-74
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    • 2019
  • Anger is a multi-dimensional concept ranging from feeling irritable to violent aggression. A growing body of literature suggests the relevance of sleep in regard to anger. The current study aims to review previous studies on the association between anger and diverse aspects of sleep including sleep disruption, chronotype, sleep disorders and sleep deprivation. An association between sleep and anger has been observed starting in the early stage of life, with sleep of infants or toddlers affecting emotional and behavioral aspects of anger. However, the association between anger and sleep is not clear in adolescents and might be due to the effects of psychosocial factors on both sleep and anger during adolescence. Subjective but not objective sleep disturbances of adults have been also associated with anger. Evening types showed more anger, which might be mediated by psychological characteristics or social jet lag of evening people. Increased anger has also been found in those with insomnia, sleep apnea, or experimental sleep-deprivation. Previous studies have reported that diverse sleep disturbances are related to anger. Future study assessing the various sleep or circadian indices and considering the multidimensional aspects of anger are needed.