• 제목/요약/키워드: Action Potential

검색결과 1,313건 처리시간 0.036초

RADIOACTIVE SOURCE SECURITY: WHY DO WE NOT YET HAVE A GLOBAL PROTECTION SYSTEM?

  • Englefield, C.
    • Nuclear Engineering and Technology
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    • 제46권4호
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    • pp.461-466
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    • 2014
  • Security of radioactive sources has been an issue since the earliest days of safety regulation of such materials. Since the events of September 11 2001, some governments and regulatory bodies have been much more focussed on these issues and have introduced extensive and enhanced security arrangements. International organisations like the IAEA and WINS have worked hard to help States in this regard. However, only a minority of States have implemented statutory security systems for radioactive source security. Why have so many States still to take action? What can be done to encourage and support these changes? This paper will offer some possible explanations for the lack of action in so many States and some potential answers to these questions.

Biological roles and an evolutionary sketch of the GRF-GIF transcriptional complex in plants

  • Kim, Jeong Hoe
    • BMB Reports
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    • 제52권4호
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    • pp.227-238
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    • 2019
  • GROWTH-REGULATING FACTORs (GRFs) are sequence-specific DNA-binding transcription factors that regulate various aspects of plant growth and development. GRF proteins interact with a transcription cofactor, GRF-INTERACTING FACTOR (GIF), to form a functional transcriptional complex. For its activities, the GRF-GIF duo requires the SWITCH2/SUCROSE NONFERMENTING2 chromatin remodeling complex. One of the most conspicuous roles of the duo is conferring the meristematic potential on the proliferative and formative cells during organogenesis. GRF expression is post-transcriptionally down-regulated by microRNA396 (miR396), thus constructing the GRF-GIF-miR396 module and fine-tuning the duo's action. Since the last comprehensive review articles were published over three years ago, many studies have added further insight into its action and elucidated new biological roles. The current review highlights recent advances in our understanding of how the GRF-GIF-miR396 module regulates plant growth and development. In addition, I revise the previous view on the evolutionary origin of the GRF gene family.

Programmed Cell Death in Bacterial Community: Mechanisms of Action, Causes and Consequences

  • Lee, Heejeong;Lee, Dong Gun
    • Journal of Microbiology and Biotechnology
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    • 제29권7호
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    • pp.1014-1021
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    • 2019
  • In the bacterial community, unicellular organisms act together as a multicellular being. Bacteria interact within the community and programmed cell death (PCD) in prokaryotes is a sort of altruistic action that enables the whole population to thrive. Genetically, encoded cell death pathways are triggered by DNA damage or nutrient starvation. Given the environmental and bacterial diversity, different PCD mechanisms are operated. Still, their biochemical and physiological aspects remain unrevealed. There are three main pathways; thymineless death, apoptosis-like death, and toxin-antitoxin systems. The discovery of PCD in bacteria has revealed the possibility of developing new antibiotics. In this review, the molecular and physiological characteristics of the three types of PCD and their development potential as antibacterial agents are addressed.

Intracellular $Ca^{2+}$ release mediates apoptosis induced by ascorbic acid (vitamin C) in HepG2 human hepatoma cells

  • Kang, Young-Shin;Lee, Yong-Soo
    • 대한약학회:학술대회논문집
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    • 대한약학회 2003년도 Proceedings of the Convention of the Pharmaceutical Society of Korea Vol.2-2
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    • pp.88.2-88.2
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    • 2003
  • Ascorbic acid (vitamin C) has been shown to have anti-cancer actions. However, the exact mechanism of this action is not fully understood. In this study we investigated the possible mechanism of anti-cancer action of ascorbic acid in HepG2 human hepatoblastoma cells. Ascorbic acid induced apoptotic cell death in a dose-dependent manner in the HepG2 cells, assessed by the flow cytometric analysis of hypodiploid nuclei stained with propodium iodide. In addition, ascorbic acid increased intracellular Ca$\^$2+/ concentration, whereas the level of reactive oxygen species was not significantly changed, suggesting that ascorbic acid may not alter cellular redox potential in the cells. (omitted)

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Effects of pyrethroid compounds on alkaline phosphatase activity in estrogen receptor positive human breast cancer cells

  • Kim, In-Young;Kang, Il-Hyun;Shin, Jae-Ho;Kim, Hyung-Sik;Lee, Su-Jung;Moon, Hyun-Ju;Kim, Tae-Sung;Shim, Eun-Youn;Moon, A-Ree;Choi, Kwang-Sik;Han, Soon-Young
    • 대한약학회:학술대회논문집
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    • 대한약학회 2002년도 Proceedings of the Convention of the Pharmaceutical Society of Korea Vol.2
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    • pp.292.2-293
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    • 2002
  • Pyrethroids are one of the most commonly used insecticides in worldwide. but it remains unclear whether pyrethroid compounds possess endocrine disrupting activity or not. T47D cells, an estrogen receptor positive human breast cancer cell line. is known to induce alkaline phosphatase (AlkP) only in response to progestins. Because the action of estrogen may be changed by the action of progestins (Kraus et al. 1995), it is important to examine the potential to produce progestin-mediated effects for determining endocrine disrupting activity of chemicals(LiLorenzo et al. 1991). (omitted)

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The Long Search for Pharmacologically Useful Anti-Inflammatory Flavonoids and Their Action Mechanisms: Past, Present, and Future

  • Kim, Hyun Pyo
    • Biomolecules & Therapeutics
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    • 제30권2호
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    • pp.117-125
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    • 2022
  • Flavonoids are known to exert anti-inflammatory effects. Their pharmacological activities have been proved using various in vitro and in vivo models. Although their action spectrum and potencies are not adequate to alleviate acute inflammatory disorders, they have the potential to treat chronic inflammatory diseases. Recent investigations have revealed that inflammatory processes are involved in many disease processes and conditions. Some examples are skin disorders, cartilage diseases, metabolic inflammatory diseases, and aging. The effects of flavonoids on these disorders have been examined. Several possible application areas for flavonoids have been studied. Local treatment of these disorders with flavonoids is favorable to avoid systemic transformation. In this review, the findings based on the experimental results from my laboratory are summarized and the future possibility of using flavonoids clinically is discussed.

억제적 통제 및 행동 감시간의 관계: 사건관련전위 연구 (The Relationships between Inhibitory Control and Action Monitoring; Event-related Potential Study)

  • 강승석;박성근;하태현;노규식;김명선;권준수
    • 인지과학
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    • 제14권4호
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    • pp.1-7
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    • 2003
  • 본 연구는 집행기능의 범주에 속하는 행동적 억제(behavioral inhibition) 기능과 행동 감시(action monitoring) 기능의 공통점을 사건관련전위 요소 및 그 뇌 신경원 분석을 통해 비교 분석하였다. 피험자들에게 Go/NoGo 과제를 수행시키면서 측정, 분석한 사건관련전위인 N200 및 P300 요소는 NoGo 조건의 경우 전두엽 쪽에서 더욱 큰 진폭을 보였다는 점에서 NoGo 조건에서 요구되는 행동적 억제기능을 반영한다고 볼 수 있었다. 또한 전두엽 영역에서 오류반응 후에 관찰되는 부적 전위인 ERN 정반응 이후 관찰되는 CRN에 비해 보다 큰 진폭과 빠른 잠재기를 보였다는 점에서 행동감시의 신호가 오류반응에 대해 보다 크게 요구되는 것이라 추론할 수 있었다. 행동적 억제의 지표인 NoGo 조건에서의 N200과 P300 요소의 잠재기와 행동감시의 지표인 ERN 요소의 진폭간에는 유의미한 부적상관이 발견되었는데, 이는 행동적 억제의 효율성이 높은 피험자일수록 행동감시의 정도 또한 크게 나타냄을 시사하는 결과라 볼 수 있었다. 이러한 집행기능 지표들간의 관련성은 이들 사건관련전위 요소들의 신경원이 거의 유사한 위치인 전대상피질(anterior cingulate cortex)에서 나타난 뇌 신경원 국소화법 결과를 통해서도 지지되었으며, 이러한 결과를 전대상피질의 집행적 통제기능이라는 맥락에서 논의하였다.

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『충북국제무예액션영화제』의 가치와 장기적 발전방안에 관한 연구 (A Study on the Value and Long-term Development of 『Chungbuk International Martial Arts and Action Film Festival』)

  • 김경식;곽상원
    • 한국엔터테인먼트산업학회논문지
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    • 제13권8호
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    • pp.303-311
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    • 2019
  • 『충북국제무예액션영화제-Chungbuk International Martial Arts and Action Film Festival』는 『충주세계무예마스터십 ChungJu World Martial Arts Masterships』과 연계 하여 진행되는 영화제로서 25개국 약 50여편의 작품을 상영하였다. 8월 30일부터 9월 6일까지인 행사 기간 총 6일 동안 장편 32편, 단편 24편의 무예액션영화를 선보이게 되면서 명실상부(名實相符)한 국내에 진행되고 있는 유일에 무예 액션 영화제가 되었다. 『충북국제무예액션영화제』는 '무예, 영화의 역사를 바꾸다!'라는 슬로건 아래 무예액션영화를 통해 무예(武藝), 무도(武道), 무술(武術)의 핵심가치인 삼재(三才: 하늘(天), 땅(地), 사람(人))를 중심으로 무예 정신이 추구하는 삶의 가치를 조명하고 점(點), 선(線), 면(面)의 공간을 중심으로 펼쳐지는 무예의 움직임을 통해 인간이 펼칠 수 있는 가장 아름다운 몸짓의 미적 가치를 탐구하였다. 그리고 이번 영화제를 통해 세계인과 함께하는 축제로 성장시킬 가능성을 엿보게 되었다. 이번 영화제를 계기로 『충북국제무예액션영화제』의 아이덴티티를 확고히 함으로써 단발성으로 사라져 버리는 영화제가 아닌 지속 가능한 영화제로의 정체성을 확립시키고 그동안 장르 영화의 한 갈래인 무예 액션 영화에 대한 이미지를 고취 시키며, 이런 이미지의 확실성을 통해 영화제만의 고유한 색깔을 가지고 국내 그리고 국제영화제들과의 차별성을 분명하게 하고, 국내에 머물지 않고 동북아(한·중·일), 동남아, 중아 아시아 아울러 세계 모든 국가가 참여할 수 있는 축제의 장을 마련하려고 한다. 그렇다면 이번 영화제의 결과를 통해 미래의 가치를 연구해 보도록 한다.

위약효과와 신경정신약물의 임상시험 (Placebo Effects and Clinical Trials of Neuropsychiatric Drugs)

  • 김성완;장지은;윤진상
    • 생물정신의학
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    • 제19권4호
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    • pp.164-171
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    • 2012
  • The placebo effect, a response observed during the placebo arm of a clinical trial, is produced by the psychobiological action of the placebo as well as by other potential contributors to symptom amelioration such as spontaneous improvement, regression to the mean, biases, concurrent treatments, and study design. From a psychological viewpoint, there are many mechanisms that contribute to placebo effects, including expectations, conditioning, learning, and anxiety reduction. Placebo responses are also mediated by opioid and non-opioid mechanisms including dopamine, serotonin, cholecystokinin, and immune mediators. During recent years, a trend towards increased placebo effects in clinical trials of neuropsychiatric drugs has been noted. Indeed, the placebo effects observed in clinical trials constitute an increasing problem and interfere with signal-detection analyses of potential treatments. Several potential factors including protocol/study design and conduct related factors may account for the placebo effect observed in clinical trials. This paper reviews key issues related to this problem and aims to identify potential solutions.

심근세포내 칼슘 이온 활용도에 미치는 Vanadate 의 효과 (Effects of Vanadate on the intracellular Calcium ion activities in mvocardial cells)

  • 이정렬;김우겸
    • Journal of Chest Surgery
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    • 제21권2호
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    • pp.291-298
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    • 1988
  • The effect of Vanadate on the isometric contraction, membrane potential and intracellular calcium ion activities of rabbit myocardial cells were investigated, using calcium selective microelectrode, filled with neutral calcium ion carrier, ETH-1001. The resting tension, the membrane potential and the intracellular calcium ion activities were recorded in normal Tyrode solution and compared with those in the contracture induced by 10 mM Vanadate. The following results were obtained: 1. The dose-response relationship between the contraction of Vanadate and twitch tension showed near-maximum response in 5mM with no corresponding changes in action potential. 2. The resting tension increased up to the amplitude of a control twitch in 10mM Vanadate with resting membrane potential, hyperpolarized. 3. Increase in intracellular calcium ion activities proceeded the contracture by 10mM Vanadate which were restored to the control level in accordance with a decrease of intracellular calcium ion activities. 4. The amplitude of contractures by 10mM Vanadate were 90-120% of the control twitch tension in which the intracellular calcium ion activities were increased about 70 times from p Ca, 7.1 in the control to p Ca, 5.8 in contractures.

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