• Title/Summary/Keyword: pre-transition

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Depletion of the Pre-RC Proteins Induces Chk1/Chk2 Independent Checkpoint Responses and Apoptotic Cell Death in HeLa Cells

  • Im, Jun-Sub;Lee, Joon-Kyu
    • Animal cells and systems
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    • v.11 no.2
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    • pp.129-134
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    • 2007
  • The initiation of eukaryotic DNA replication requires assembly of the pre-replicative complex (Pre-RC) through the concerted action of Orc, Cdc6, Cdt1 and Mcm2-7 complex during G1 phase. The pre-RC assembly licenses individual replication origins for the initiation of DNA replication and sufficient number of the pre-RC is essential for proper progression of S phase. However, it is not well known how cells recognize the completion of the pre-RC assembly before G1-S transition. In order to understand the cellular responses to the defects in pre-RC assembly, we depleted the known components of pre-RC proteins using the small interference RNAs in HeLa cells. Although the defects of pre-RC assembly by the depletion of the pre-RC proteins such as Orc2, Cdt1, Mcm2 & Mcm10 did not elicit the activation of Chk1- or Chk2-dependent checkpoint pathways, these cells still showed significant decrease in the cellular level of Cdc25A proteins. These results suggests that a novel checkpoint pathway exist in HeLa cells, which is not dependent upon Chk1 or Chk2 proteins and play essential roles in the cellular responses to the defects in the pre-RC assembly. Also, among those four proteins tested in this study, the depletion of Mcm10 and Cdt1 proteins significantly increased the apoptotic cell death in HeLa cells, suggesting that these proteins not only play roles in the pre-RC assembly, but also are involved in the checkpoint responses to the defects in the pre-RC assembly.

Transmission Electron Microscopy Characterization of Early Pre-Transition Oxides Formed on ZIRLOTM

  • Bae, Hoyeon;Kim, Taeho;Kim, Ji Hyun;Bahn, Chi Bum
    • Corrosion Science and Technology
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    • v.14 no.6
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    • pp.301-312
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    • 2015
  • Corrosion of zirconium fuel cladding is known to limit the lifetime and reloading cycles of fuel in nuclear reactors. Oxide layers formed on ZIRLO4^{TM}$ cladding samples, after immersion for 300-hour and 50-day in a simulated primary water chemistry condition ($360^{\circ}C$ and 20 MPa), were analyzed by using the scanning transmission electron microscopy (STEM), in-situ transmission electron microscopy (in-situ TEM) with the focused ion beam (FIB) technique, and X-ray diffraction (XRD). Both samples (immersion for 300 hours and 50 days) revealed the presence of the ZrO sub-oxide phase at the metal/oxide interface and columnar grains developed perpendicularly to the metal/oxide interface. Voids and micro-cracks were also detected near the water/oxide interface, while relatively large lateral cracks were found just above the less advanced metal/oxide interface. Equiaxed grains were mainly observed near the water/oxide interface.

Effects of Smoking Cessation Education for Male College Students (남자 대학생에 대한 금연교육의 효과)

  • Kwon, Mi-Kyung;Bang, Kyung-Sook
    • The Journal of Korean Academic Society of Nursing Education
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    • v.19 no.4
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    • pp.640-647
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    • 2013
  • Purpose: The purpose of this study was to identify the effectiveness of smoking cessation education using the transtheoretical model on the process of change, smoking temptation, decisional balance and stage change transition. Methods: A nonequivalent control group non-synchronized design was used for this study. The study population was 44 male college students in the experimental group and 66 students in the control group. Smoking cessation education was administered to the experimental group at one university. Descriptive analysis, t-test, and ANCOVA were used with the SPSS 19.0 program to analyze the data. Results: After providing a smoking cessation program, the experimental group showed significantly higher scores for self-efficacy for smoking cessation, process of change, and a lower score in decisional balance for pros of smoking and nicotine dependancy compared to the control group two weeks after the pre-test. However, no significant differences were found at four weeks after the pre-test. Conclusion: The findings indicate that this program could have a positive effect on process of change, decisional balance and stage transition for college student smokers.

Novel Two Stage AC-to-DC Converter with Single Switched Zero Voltage Transition Boost Pre-Regulator using DC-Linked Energy Feedback (새로운 영전압 스위칭 이단방식의 고역률 컨버터)

  • Roh, Chung-Wook;Moon, Gun-Woo;Jung, Young-Seok;Youn, Myung-Joong
    • Proceedings of the KIEE Conference
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    • 1996.07a
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    • pp.385-387
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    • 1996
  • A novel two stage soft-switching ac-to-dc convener with power factor correction is proposed. The proposed convener provides zero-voltage-switching (ZVS) condition to main switch of boost pre-regulator without auxiliary switch. Comparing to the conventional two stage approach(ZVS-PWM boost rectifier followed by off-line ZVS dc-dc step down converter), the proposed approach is simple and reducing EMI noise problem. A new simple DC-linked energy feedback circuit provides zero-voltage-switching condition to boost pre-regulator without imposing additional voltage and current stresses and loss of PWM capability. Operational principle, analysis, control of the proposed converter together with the simulation results of 1KW prototype are presented.

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A Study of the Pre-Resistance Effects on the Optimization For Performance of the Ignition System with the Breaker Point Type (Breaker Point 型 점火裝置 性能 을 極大化하기 위한 Pre - Resistance 효果 에 對한 硏究)

  • 손병진;신영철
    • Transactions of the Korean Society of Mechanical Engineers
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    • v.6 no.2
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    • pp.133-139
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    • 1982
  • One of factors that affect combustion in the cylinder of the engine is to keep a greater energy in the ignition system to minimize pollutant emissions and to increase its performance of the low temperature. This paper reviews theoretically the state and input variables of the ignition system from the state transition equation. Effects on characteristics of the system such as primary current, secondary available voltage and spark duration by reducing the pre-resistance from 3.5 to 0 ohm in 12V system is experimentally investigated when the ignition coil has a primary resistance of 1.5 ohms ad the dwell angle of the breaker point is 43.2 degrees (0.75 radian). Advantages and limitations for using the low resistance of the primary circuit are also presented to optimize the performance of the ignition system with the breaker point.

A New Pre-Emphasis Driver Circuit for a Packet-Based DRAM (패킷 방식의 DRAM에 적용하기 위한 새로운 강조 구동회로)

  • Kim, Jun-Bae;Kwon, Oh-Kyong
    • The Transactions of the Korean Institute of Electrical Engineers C
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    • v.50 no.4
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    • pp.176-181
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    • 2001
  • As the data rate between chip-to-chip gets high, the skin effect and load of pins deteriorate noise margin. With these, noise disturbances on the bus channel make it difficult for receiver circuits to read the data signal. This paper has proposed a new pre-emphasis driver circuit which achieves wide noise margin by enlarging the signal voltage range during data transition. When data is transferred from a memory chip to a controller, the output boltage of the driver circuit reaches the final values through the intermediate voltage level. The proposed driver supplies more currents applicable to a packet-based memory system, because it needs no additional control signal and realizes very small area. The circuit has been designed in a 0.18 ${\mu}m$ CMOS process, and HSPICE simulation results have shown that the data rate of 1.32 Gbps be achieved. Due to its result, the proposed driver can achieved higher speed than conventional driver by 10%.

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Inhibitory Effects of Cultivated Wild Ginseng on the Differentiation of 3T3-L1 Pre-adipocytes

  • Mollah, Mohammad Lalmoddin;Cheon, Yong-Pil;In, Jun-Gyo;Yang, Deok-Chun;Kim, Young-Chul;Song, Jae-Chan;Kim, Kil-Soo
    • Journal of Ginseng Research
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    • v.35 no.1
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    • pp.45-51
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    • 2011
  • Wild ginseng has been used as a traditional medicine for thousands of years and for increase physical strength in Korea, China and Japan. This study reports that cultivated wild ginseng (CWG) inhibits adipocyte differentiation of 3T3-L1 pre-adipocytes in a concentration-dependent manner. Inhibition of adipocyte differentiation is one possible anti-obesity strategy. CWG inhibits the expression of the adipocyte differentiation regulator peroxisome proliferators-activated receptor (PPAR)${\gamma}$ and CCAAT/enhancer-binding protein ${\alpha}$mRNA. It also inhibited the expression of PPAR${\gamma}$ and adiponectin at the protein level during the differentiation of pre-adipocytes into adipocytes. Additionally, CWG blocked the cell cycle at the sub-$G_1$ phase transition, causing cells to remain in the pre-adipocyte state. These results indicate that CWG inhibits adipocyte differentiation and adipogenesis through pre-adipocyte cell cycle arrest in cultured 3T3-L1 cells.

Pre-Natal Epigenetic Influences on Acute and Chronic Diseases Later in Life, such as Cancer: Global Health Crises Resulting from a Collision of Biological and Cultural Evolution

  • Trosko, James E.
    • Preventive Nutrition and Food Science
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    • v.16 no.4
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    • pp.394-407
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    • 2011
  • Better understanding of the complex factors leading to human diseases will be necessary for both long term prevention and for managing short and long-term health problems. The underlying causes, leading to a global health crisis in both acute and chronic diseases, include finite global health care resources for sustained healthy human survival, the population explosion, increased environmental pollution, decreased clean air, water, food distribution, diminishing opportunities for human self-esteem, increased median life span, and the interconnection of infectious and chronic diseases. The transition of our pre-human nutritional requirements for survival to our current culturally-shaped diet has created a biologically-mismatched human dietary experience. While individual genetic, gender, and developmental stage factors contribute to human diseases, various environmental and culturally-determined factors are now contributing to both acute and chronic diseases. The transition from the hunter-gatherer to an agricultural-dependent human being has brought about a global crisis in human health. Initially, early humans ate seasonally-dependent and calorically-restricted foods, during the day, in a "feast or famine" manner. Today, modern humans eat diets of caloric abundance, at all times of the day, with foods of all seasons and from all parts of the world, that have been processed and which have been contaminated by all kinds of factors. No longer can one view, as distinct, infectious agent-related human acute diseases from chronic diseases. Moreover, while dietary and environmental chemicals could, in principle, cause disease pathogenesis by mutagenic and cytotoxic mechanisms, the primary cause is via "epigenetic", or altered gene expression, modifications in the three types of cells (e.g., adult stem; progenitor and terminally-differentiated cells of each organ) during all stages of human development. Even more significantly, alteration in the quantity of adult stem cells during early development by epigenetic chemicals could either increase or decrease the risk to various stem cell-based diseases, such as cancer, later in life. A new concept, the Barker hypothesis, has emerged that indicates pre-natal maternal dietary exposures can now affect diseases later in life. Examples from the studies of the atomic bomb survivors should illustrate this insight.

Improving printability by designing a multi-layered coating structure (I) - The effect of binder properties in the pre-coating layer on the characteristics of the top-coating layer - (다층도공층의 설계에 의한 인쇄적성 개선 (제1보) - 프리코팅층의 바인더 물성이 탑코팅층의 특성에 미치는 영향 -)

  • Kim, Sun-Kyung;Won, Jong Myoung;Lee, Yong-Kyu
    • Journal of Korea Technical Association of The Pulp and Paper Industry
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    • v.48 no.1
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    • pp.27-33
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    • 2016
  • This study was carried out in order to investigate the effect of binder properties in pre-coating layer on the characteristics of top-coating layer and print mottle of coated paper. Four different latices were used as a binder in pre-coating layer, and coating color prepared with a same formulation was applied for top-coating. The properties and print mottle of coated paper were evaluated. It was found that glass transition temperature (Tg) was the important factor to control the properties of pre- and top-coating layer. PPS roughness of coated paper was decreased and paper gloss was increased with applying binder which has lower Tg. Properties of top-coating layer were affected by the binder used in pre-coating layer. Print mottle of coated paper was improved with using binder which has lower Tg in pre-coating layer. These results indicate that final printability and properties of top-coating layer can be improved with using suitable binder in pre-coating layer.

A study on changes in physician behavior after enforcing pre-review system (사전심사제도 도입에 다른 의사의 진료행태 변화)

  • Kim Sera;Kim Jin Hee
    • Health Policy and Management
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    • v.14 no.4
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    • pp.88-113
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    • 2004
  • Starting from April, 2003, new pre-review system has been introduced and implemented to reduce unnecessary conflict with medical care organizations caused by current retrospective claim review system and to enhance efficiency of review system. The main purpose of pre-review system is to educate doctors to contrive adequacy of medical services. This research mainly focuses on effectiveness of pre-review system's influence on physicians' behavior changes. The analysis-participants were drawn from 1,449 clinics which implemented pre-review system, since April of 2003. The research results are as followings. First, the amount per claim has reduced by $\\3,154$, days of visit per claim by 0.1 day, and amount per visit by $\\412$, which were statistically significant. Second, anesthesiologists have decreased in three indicators the most, and the internists had least of changes. Third, the amount per claim and days of visit per claims has dropped significantly on physicians with less periods of practice and physicians with more ages. Fourth, the clinics without the expensive medical equipments, the city clinics showed significant decrease on days of visit per claim. Fifth, in intervention methods, the one-to-one education showed more significant decrease on amount per visit rather than information feedback by paper. In conclusion, the pre-review system have an impact on self-imposed physician behavioral change. The outcome of this research may be utilized for future extension implementation of pre-review system. Furthermore, it is showed that ability of transitions in medical services review system according to the future transition of payment system and context of health service policy.