• Title/Summary/Keyword: membrane processes

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Role of tea catechins in prevention of aging and age-related disorders

  • Khanna, Arjun;Maurya, Pawan Kumar
    • CELLMED
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    • v.2 no.1
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    • pp.2.1-2.11
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    • 2012
  • Tea polyphenols especially catechins have long been studied for their antioxidant and radical scavenging properties. Scientists throughout the world have investigated the usefulness of the regular green tea consumption in several disease conditions. In-vitro and in-vivo experiments on catechins especially epigallocatechingallate have revealed a significant role in many ways. Reactive oxygen species have been increasingly implicated in the pathogenesis of many diseases and important biological processes. Toxic effects of these oxidants, commonly referred to as oxidative stress, can cause cellular damage by oxidizing nucleic acids, proteins, and membrane lipids. Oxidative stress has been related to aging and age related disorders. It is found that in a wide variety of pathological processes, including cancer, atherosclerosis, neurological degeneration, Alzheimer's disease, ageing and autoimmune disorders, oxidative stress has its implications. Catechins have been reported to be useful in combating aging and age related disorders like cancer, cardiovascular disorders and neurodegenerative diseases. In this mini review we will discuss such studies done across the globe.

Prediction of Earings in the Deep Drawing Processes of a Cylindrical Cup (원통컵 디프드로잉 공정의 귀발생 예측)

  • 이승열;이승열;금영탁;정관수;박진무
    • Transactions of Materials Processing
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    • v.4 no.3
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    • pp.222-232
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    • 1995
  • The planar anisotripic FEM analysis for predicting earing profiles and draw-in amounts in the deep-drawing process is introduced. An implicit, incremental, updated Lagrangian formulation with a rigid-viscoplastic constitutive equation is employed. Contact and friction are considered through the mesh-based unit vector and normal contact pressure. The consistent full set of governing relations, which is comprising euilbrium and geometric constraint equations, is appropriately linearized. Barlat's strain-rate potential is employed, whose in-plane anisotropic properties are taken into account with anisotropic coefficients and potential parameters. The linear triangular membrane elements are used for depicting the formed sheet. In the numerical simulations of deep drawing processes of a flat-top cylindrical cup for 2090-T3 aluminum alloy sheet show good agreement with experiments, although some discrepancies were observed in the directional trend of cup height and thickness strains.

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Using Polypyrrole for Drug Delivery System (폴리피롤을 이용한 약물전달시스템)

  • Lee, Sang-Jo;Lee, Seung-Ki;Oh, Myung-Hwan;Park, Jung-Ho
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2002.11a
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    • pp.448-451
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    • 2002
  • The possibility of using polypyrrole as a drug delivery system(DDS) has been studied using indicate (Phenol red) and substance with therapeutic activity(Sodium salicylate). In aqueous solution, negative potential is applied to polypyrrole then anion(with therapeutic activity) of sodium salicylate is released by redox processes of polypyrrole. The release amount of anionic drugs from polypyrrole is measured by UV-visible spectrometer which can measure UV-absorbance of materials. Electrode area that use for release amount measurement is$50mm^{2}(5{\times}10mm)$,and thickness of polypyrrole membrane is $15{\mu}m$. DC 1V applied in saline solution, the release amount according to time increased gradually. In various electrode area, release amount of anionic drug is directly to electrode area.

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Earing Predictions in the Deep-Drawing Process of Planar Anisotropic Sheet-Metal (평면 이방성 박판 딥드로잉 공정의 귀발생 예측)

  • 이승열;금영탁;정관수;박진무
    • Proceedings of the Korean Society for Technology of Plasticity Conference
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    • 1994.03a
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    • pp.118-128
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    • 1994
  • The planar anisotropic FEM analysis for predicting the earing profiles and draw-in amounts in the deep-drawing processes is introduced. An implicit, incremental, updated Lagrangian formulation with a rigid-viscoplastic constitutive equation is employed. Contact and friction are considered through the mesh-based unit vectors and the normal contact pressure. the consistent full set of governing relations, comprising equilibrium and geometric constraint equations, is appropriately linearized. Barlat's strain-rate potential is employed, whose in-plane anisotropic properties are taken into account with anisotropic coefficients and potential parameter. The linear triangular membrane elements are used for depicting the formed sheet. with the numerical simulations of deep drawing processes of flat-top cylindrical cup for the 2090-T3 aluminum effects on the earing behavior are examined. Earing predictions made for the 2090-T3 aluminum alloy sheet show good agreement with experiments, although some discrepancies were observed in the directional trend of cup height and thickness strains.

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Cost comparison of pretreatment processes in large SWRO desalination plant (대규모 해수담수화 플랜트에서의 전처리공정 비용 분석)

  • Kim, Youngmin;Kim, Jin-Ho;Lee, Sangho;Lee, Chang-Kyu;Park, Kwang Duk;Choi, June-Seok
    • Journal of Korean Society of Water and Wastewater
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    • v.27 no.5
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    • pp.555-560
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    • 2013
  • A cost analysis method for pretreament processes of a large scale seawater desalination plant was considered using a cost estimation model, WaTER (Water Treatment Estimation Routine). This model is based on cost functions of U.S. EPA to conduct economic analysis of water treatment facilities. A virtual seawater desalination plant which has pretreatment production capacity of $100,000m^3$ per day was chosen as a model plant. Dual media filtration and microfiltration systems were compared as pretreatment process, and the following reverse osmosis process was modeled. As a result, microfiltration showed a price competitiveness in condition of operating with reverse osmosis process by reducing the loads of water treatment and membrane cleaning despite it's high annual cost.

Cell signaling and therapeutic drug target for the treatment of liver cirrhosis

  • Kim, Sang-Geon
    • Proceedings of the PSK Conference
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    • 2002.10a
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    • pp.115-130
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    • 2002
  • Signal transduction refers to the processes by which cells perceive the environment and/or internal status. In many physiological responses, cellular signals are activated by the transducers attached to the cell surface plasma membrane in response to chemical modulators. Advances in information technology are required in the pharmaceutical sciences to screen and explore the potential therapeutic agents. (omitted)

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A General Tool Surface Contact Search and its Application to 3-D Sheet Forming (일반적인 금형면에서의 접촉탐색과 3차원 박판성형에의 응용)

  • 서의권;심현보
    • Proceedings of the Korean Society for Technology of Plasticity Conference
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    • 1997.03a
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    • pp.121-124
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    • 1997
  • In the present study, a general tool surface contac search ad check algorithm is proposed. A general tool surface is described by triangular FE mesh. To check a proposed algorithm, clover cup and L-shape cup deep drawing processes are calculated. The elastic-plastic FEM using SEAM (Shear Energy Augmented Membrane) element is adapted for numerical stability.

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Regulation of $Ca^{2+}$ Influx by Membrane Potential in Microglia

  • Lee, Jungsun;Uhm, Dae-Yong;Sungkwon Chung
    • Proceedings of the Korean Biophysical Society Conference
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    • 2002.06b
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    • pp.39-39
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    • 2002
  • Microglia are known to have an important function as brain macrophage during immunological processes, oncogenesis, and regeneration in the central nervous system (CNS). A wide variety of ion channels have been identified and characterized in microglia including inward rectifier $K^{+}$ channel (Kir), voltage dependent $K^{+}$ channel (Kv), $Ca^{2+}$-release activated $Ca^{2+}$ channel (CRAC).(omitted)

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Inhibitions of $H^+$-ATPases and Ion Channels by Lanthanum

  • Kim, Young-Kee;Cho, Kwang-Hyun;Park, Soo-Jin
    • Proceedings of the Korean Biophysical Society Conference
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    • 2001.06a
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    • pp.39-39
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    • 2001
  • Many physiological processes of plant cells, such as nutrient uptake, salt tolerance, and cell enlargement, are mediated by ion transports across the plasma membrane. H$^{+}$-ATPases on both plasma and vacuolar membranes play major roles on active transports and ion channels mediate passive transports of various ions. It has been known that these proteins involved in cellular osmotic regulation and salt tolerance in the salt-accumulated soils.(omitted)

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Targeting Cell-Cell and Cell-Matrix Interactions and Its Therapeutic Applications

  • Kim, In-San
    • Proceedings of the PSK Conference
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    • 2003.10a
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    • pp.100-101
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    • 2003
  • Cell-cell and cell-matrix interaction is clearly required for metazoans not only to hold their cells together but also to conduct more sophisticated biological processes. Each cell has adhesion molecules on its cell membrane to link extracellular matrix and adjacent cells to the intracellular cytoskeleton, and also to transduce signals. In complex metazoans, information is transmitted from one cell to another by mechanisms such as direct intercellular communication, soluble signal molecules among distant cells, and local cellular environments formed by highly specialized extracellular matrix. (omitted)

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