• 제목/요약/키워드: free radical theory

검색결과 22건 처리시간 0.02초

Styren과 acrylonitrile의 과상 공중합을 위한 회분식 반응기의 모델링 및 모사 (Modeling and simulation of a batch reactor for bulk copolymerization of styrene and acrylonitirle)

  • 유기윤;황우현;백종은;이현구
    • 제어로봇시스템학회:학술대회논문집
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    • 제어로봇시스템학회 1994년도 Proceedings of the Korea Automatic Control Conference, 9th (KACC) ; Taejeon, Korea; 17-20 Oct. 1994
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    • pp.207-212
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    • 1994
  • A mathematical model is developed for a batch reactor in which the free radical bulk copolymerization of styrene and acrylonitrile takes place. In this model, we introduce the free volume theory to quantify the diffusion controlled termination and propagation reactions, and develop a model for the chain length dependent termination reaction in the context of the pseudo kinetic rate constant method(PKRCM). The simulation results from this model are found to be in good agreement with experimental data under different copolymerization conditions. The present model can predict both the copolymer composition and the number and weight average molecular weights. These kinetic approaches provide greater insight into the performance of the batch reactor used for the free radical bulk copolymerization of styrene and acrylonitirle.

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노화의 기전과 예방 (Mechanism of aging and prevention)

  • 김재식
    • IMMUNE NETWORK
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    • 제1권2호
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    • pp.104-108
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    • 2001
  • Aging is a senescence and defined as a normal physiologic and structural alterations in almost all organ systems with age. As Leonard Hayflick, one of the first gerontologists to propose a theory of biologic aging, indicated that a theory of aging or longevity satisfies the changes of above conditions to be universal, progressive, intrinsic and deleterious. Although a number of theories have been proposed, it is now clear that cell aging (cell senescence) is multifactorial. No single mechanism can account for the many varied manifestations of biological aging. Many theories have been proposed in attempt to understand and explain the process of aging. Aging is effected in individual by genetic factors, diet, social conditions, and the occurrence of age-related diseases as diabetes, hypertension, and arthritis. It involves an endogenous molecular program of cellular senescence as well as continuous exposure throughout life to adverse exogenous influences, leading to progressive infringement on the cell's survivability so called wear and tear. So we could say the basic mechanism of aging depends on the irreversible and universal processes at cellular and molecular level. The immediate cause of these changes is probably an interference in the function of cell's macromolecules-DNA, RNA, and cell proteins-and in the flow of information between these macromolecules. The crucial questions, unanswered at present, concerns what causes these changes in truth. Common theories of aging are able to classify as followings for the easy comprehension. 1. Biological, 1) molecular theories - a. error theory, b. programmed aging theory, c. somatic mutation theory, d. transcription theory, e. run-out-of program theory, 2) cellular theories - a. wear and tear theory, b. cross-link theory, c. clinker theory, d. free radical theory, e. waste product theory, 3) system level theory-a. immunologic/autoimmune theory, 4) others - a. telomere theory, b. rate of living theory, c. stress theory, etc. Prevention of aging is theoretically depending on the cause or theory of aging. However no single theory is available and no definite method of delaying the aging process is possible by this moment. The most popular action is anti-oxidant therapy using vitamin E and C, melatonin and DHEA, etc. Another proposal for the reverse of life-span is TCP-17 and IL-16 administration from the mouse bone marrow B cell line study for the immunoglobulin VDJ rearrangement with RAG-1 and RAG-2. Recently conclusional suggestion for the extending of maximum life-span thought to be the calory restriction.

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Density Functional Theory (DFT) Study of Gas-phase O.C Bond Dissociation Energy of Models for o-TEMPO-Bz-C(O)-Peptide: A Model Study for Free Radical Initiated Peptide Sequencing

  • Kwon, Gyemin;Kwon, Hyuksu;Lee, Jihye;Han, Sang Yun;Moon, Bongjin;Oh, Han Bin;Sung, Bong June
    • Bulletin of the Korean Chemical Society
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    • 제35권3호
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    • pp.770-774
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    • 2014
  • The bond dissociation energy (BDE) of the chemical bond between the carbon and oxygen atoms of a simple TEMPO-derivative is calculated by employing the density functional theory, the $2^{nd}$ order M${\phi}$ller-Plesset (MP2) perturbation theory, and complete basis set (CBS) methods. We find that BDE of the positive ion of the TEMPO-derivative is larger at least by 7 kcal/mol than that of the negative ion, which implies that the dissociation reaction rate of the positive ion should be slower than that of the negative ion. Such theoretical predictions are contrary to the results of our previous experiments (Anal. Chem. 2013, 85, 7044), in which the larger energy was required for negative o-TEMPO-Bz-C(O)-peptides to undergo the dissociation reactions than for the positive ones. By comparing our theoretical results to those of the experiments, we conclude that the dissociation reaction of o-TEMPO-Bz-C(O)-peptide should occur in a complicated fashion with a charge, either positive or negative, probably being located on the amino acid residues of the peptide.

Acanthopanax sessiliflorus stem confers increased resistance to environmental stresses and lifespan extension in Caenorhabditis elegans

  • Park, Jin-Kook;Kim, Chul-Kyu;Gong, Sang-Ki;Yu, A-Reum;Lee, Mi-Young;Park, Sang-Kyu
    • Nutrition Research and Practice
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    • 제8권5호
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    • pp.526-532
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    • 2014
  • BACKGROUND/OBJECTIVES: Acanthopanax sessiliflorus is a native Korean plant and used as a traditional medicine or an ingredient in many Korean foods. The free radical theory of aging suggests that cellular oxidative stress caused by free radicals is the main cause of aging. Free radicals can be removed by cellular anti-oxidants. MATERIALS/METHODS: Here, we examined the anti-oxidant activity of Acanthopanax sessiliflorus extract both in vitro and in vivo. Survival of nematode C. elegans under stress conditions was also compared between control and Acanthopanax sessiliflorus extract-treated groups. Then, anti-aging effect of Acanthopanax sessiliflorus extract was monitored in C. elegans. RESULTS: Stem extract significantly reduced oxidative DNA damage in lymphocyte, which was not observed by leaves or root extract. Survival of C. elegans under oxidative-stress conditions was significantly enhanced by Acanthopanax sessiliflorus stem extract. In addition, Acanthopanax sessiliflorus stem increased resistance to other environmental stresses, including heat shock and ultraviolet irradiation. Treatment with Acanthopanax sessiliflorus stem extract significantly extended both mean and maximum lifespan in C. elegans. However, fertility was not affected by Acanthopanax sessiliflorus stem. CONCLUSION: Different parts of Acanthopanax sessiliflorus have different bioactivities and stem extract have strong anti-oxidant activity in both rat lymphocytes and C. elegans, and conferred a longevity phenotype without reduced reproduction in C. elegans, which provides conclusive evidence to support the free radical theory of aging.

노화(老化)의 연구동향(硏究動向)에 관한 고찰(考察) (The Study on Aging Process Research)

  • 이홍민;서정철;김용석
    • Journal of Acupuncture Research
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    • 제18권1호
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    • pp.146-156
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    • 2001
  • Objectrve : To research the trends of the study related to aging process, and to establish the direction of the study on aging process. Method : We reviewed the journal and essay about the aging process which are published as well in Korea as in foreign country. Results : 1. The study on the Oriental Medicine field can be classfied with the fourth. first, the study of single herb medication's effect on the aging process. second, the study of multiple herb medication's effect on the aging process. third, the study of herb-acupuncture solution's effect on the aging process. fourth, journal review. We find the fact that the study on the Oriental Medicine is concerned with pathology of deficiency syndrome of the kidneys, retention of phlegm and fluid, blood stasis. 2. On the Western Medicine field, mechanism and pathology of aging pracess primarily has been studied. The mechanism of aging process is classified with 'Wear and tear theory' and 'Genome-based theory'. Among the mechanism of aging process, 'Free radical theory' is the most important. Additionally 'Senescence-Accelerated Mouse' has been studied. 3. We review the journal published in foreign country and its subject was the following: first, moxibustion combined with acu-area skin allograft therapy for the aging was effective, second, the traditional chinese medicine bu-zhong-yi-qi-tang in mice have anti-aging effect. third, the overview Preventive geriatrics of Traditional chinese medicine. 4. We researched anti-aging effect study in the journal of the Korean Acupuncture and Moxibustion, and we found a few journal of Herb-acupuncture solution's anti-aging effect. Hereafter, it is necessory that we will study about relationship between acupuncture-moxibustion therpy and anti-aging effect using Senescence-Accelerated Mouse.

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천연색 사진현상에서 은색소 표백법에 관한 고찰 (A Study on Silver Dye Bleach Process for the Development of Color-photography)

  • 박경환
    • 한국인쇄학회지
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    • 제1권1호
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    • pp.43-48
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    • 1983
  • For the development of colored-proto grapby, the silver dye blech processes were extensively studied. For the first time, the developed silver was main catalyst, but recently active organic compounds are widely used as organic catalyst. They were guinoxaline and phenazine derivatives and it may forrned protonated free radical(${AH_2}^+$) under the presence of strong acid. Herewith the chemical reaction involved those catalyst and it's kinetic theory were described. Also, properties of the product with organic catalyst and improved process was reviewed.

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경영학(經營學) (조직이론(組織理論)) 연구방법(硏究方法)에 있어서 변증법적(辨證法的) 접근(接近)에 대한 고찰(考察) - 인식논적(認識論的) 이해(理解)를 중심(中心)으로 - (A Study on Dialectical Theory for a Management Research - Epistemological Inquiry -)

  • 백광기
    • 산학경영연구
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    • 제4권
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    • pp.51-70
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    • 1991
  • For the past few decades functionalism have dominated the epistemological arena in organizational science. However, the positivist-inspired movement of functionalism have proved inadequate for explaining the radical transformations of organizations. During the last decade dialectical theory has been starting to be heard. This paper identifies the dialectic as the unifying principle of a broad and diffuse tradition of thought. Beginning with a excavation of the philosophical foundations of dialectical theory in the thought of Kant, Hegel, and Marx, this paper goes through the various twists and the turns of the dialectic in the major twentieth-century movements of neomarxism, phenomenology, and critical theory. Also, this paper presents the implications of the dialectical approach in organization science. The discipline of organization theory has been imprisoned by its functionalism, therefore, stimulating an awareness through which it can begin to set itself free has become imperative. Dialectical theory, be cause it is essentially a process perspective, focuses on the dimension currently missing in much organizational thought, It opens analysis to the processes through which actors carve out and stabilize a sphere to the processes through which actors carve out and stabilize a sphere of rationality and those through which such rationalized spheres dissolve.

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소음인(少陰人) 십이미관중탕(十二味寬中湯), 오수유부자이중탕(吳茱萸附子理中湯)이 흰쥐의 뇌(腦)와 간조직(肝組織)의 항산화(抗酸化) 기전(機轉)에 미치는 영향(影響) (A Study on Antioxidative Effects of Sipyimiguanjungtang and Osuyubujayijungtang, Korean Traditional Prescriptions for Soum Constitutes, in Brain and Liver of Rat)

  • 정봉연;송일병
    • 사상체질의학회지
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    • 제11권2호
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    • pp.227-250
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    • 1999
  • 소음인(少陰人) 십이미관중탕(十二味寬中湯)과 오수유부자이중탕(吳茱萸附子理中湯)의 항산화(抗酸化) 효능(效能)을 검증(檢證)하기 위해, 약재(藥材)의 항산화력(抗酸化力)을 측정(測定)하였으며, 흰쥐에 투여(投與)하여 뇌(腦)와 간(肝) 조직(組織)의 항산화력(抗酸化力) 증강(增强) 효과(效果)를 실험(實驗)한 결과 유의성(有意性) 있는 성적(成績)을 얻었기에 보고(報告)하는 바이다. 십이미관중탕(十二味寬中湯)과 오수유부자이중탕(吳茱萸附子理中湯)의 화학적(化學的) 항산화력(抗酸化力)을 검증(檢證)한 결과(結果) 비교적 높은 항산화(抗酸化) 활성(活性)을 보여주었다. HepG2 세포주(細胞株)와 적혈구(赤血球)를 이용한 항산화력(抗酸化力) 검증(檢證)에서도 높은 활성(活性)을 보여주었으며. 특히 십이미관중탕(十二味寬中湯)은 강한 수용성 항산화력제(抗酸化劑))로 알려진 vitamin C와 유사한 결과를 보였다. 실험용(實驗用) 흰쥐에게 탕제(湯劑) 추출물(抽出物)을 4주간(週間) 투여(投與)한 뒤 체중증가량(體重增加量)과 GOT 활성(活性)을 측정(測定)한 결과 탕제(湯劑) 비투여군(非投與群)과 유의적(有意的) 차이(差異)를 보이지 않아 탕제(湯劑) 투여(投與)에 의한 독성(毒性)은 없는 것으로 사료(思料)된다. 활성산소(活性酸素) 발생제(發生劑)인 2.2'-azobis(amidinopropane) dihydrochloride (AAPH)로 산화적(酸化的) 손상(損傷)을 유발(誘發)한 실험용(實驗用) 흰쥐에서 십이미관중탕(十二味寬中湯) 투여군(投與群)은 혈장(血漿) 총항산화력(總抗酸化力), 혈장(血漿) 지질과산화(脂質過酸化)가 억제(抑制)되었으며, 혈장(血漿) thiol 그룹의 감소(減少)도 억제(抑制)되었으나. 오수유부자이중탕(吳茱萸附子理中湯) 투여군(投與群)에서는 유의적(有意的) 차이(差異)가 나타나지 않았다. 십이미관중탕(十二味寬中湯) 투여군(投與群)은 간(肝) 및 뇌조직(腦組織)에서 AAPH로 유도(誘導)된 산화적(酸化的) 손상(損傷)을 유의적(有意的)으로 억제(抑制)하였으며, 체내(體內) 중요(重要) 항산화(抗酸化) 물질(物質)인 glutathione을 보호(保護)하여 체내(體內) 항산화(抗酸化) 능력(能力)을 증진(增進)시킨 것으로 사료(思料)된다. 오수유부자이중탕(吳茱萸附子理中湯) 투여군(投與群)은 제한적(制限的)인 효과(效果)만을 보였다. 십이미관중탕(十二味寬中湯)은 항산화(抗酸化) 효과(效果)가 높은 처방(處方)으로 볼 수 있는 바 임상(臨床)에서 노화방지(老化防止)에 널리 활용(活用)될 수 있을 것으로 사료(思料)된다.

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국내문헌(國內文獻)(35)에 나타난 항노화(抗老化) 및 항산화(抗酸化)의 실험적(實驗的) 연구(硏究)에 대(對)한 검색(檢索) (Search of Experimental Studies(35) on Anti aging and Anti oxidant in Korea)

  • 안상원;이철완
    • 대한한의학회지
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    • 제19권2호
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    • pp.373-390
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    • 1998
  • 35 theses conducted in Korea on the topic of senescence or anti-oxidant were classified on the basis of research methods, animals used for the experiments, and research items. Evaluating these research works with respect to the Free Radical Theory, the following conclusions were reached. 1. Of the 17 theses written in the Oriental medicine aspect, three theses used a single herb, nine theses used a complex prescription, four theses concentrated on the usage of the medicinal acupuncture, and one research paper focused on using scientific components. Common objection of these papers were on the verification of the efficacy of herbs. 2. Of the 18 these written in the Western medicine aspect, five theses used a single drug, seven theses conducted a research on the changes due to senescence, and 6 papers were on variety of topics. The main focus of these works were on the mechanism and pathology related to the senescence rather than on the suppression of senescence. 3. Among the theses written in the Oriental medicine perspective, a total of 48 herbs were utilized. 26 of these herbs has a tonification function on the Kidney. Six out of nine complex prescription mentioned above has a function of tonifying the Kidney. 4. With respect to the research subjects used on the experiments, 8 theses have used Senescence-Accelerated mice, 13 theses have used Sprague-Dawley mice, and remaining 7 papers have used human or other animals. 5. These are the categorization of the research items used: the weight (11) and weight changes of the visceral organs (9), the measurement of the content of peroxide-disease (9), the measurement of enzyme vitality (21), the blood and urine test (10), the experiment concerning immune system (3), the influence on the hepatic capability of metabolizing foreign substance (3), the effect on hepatic cell protection (3), the measurement of both the suppression of Free Radical and ability to create Free Radical (2), the measurement of effect of suppresing MDA(malondialdehyde) (4), the effect of eliminating DPPH Radical (2), and experiements about the functions (2). 6. The rate of vitalization of well known anti-oxidants such as Superoxide dismutase (SOD), Protein-bound SH, Nonprotein-bound SH, Glutathione(GSH), Catalase, and etc. were tested in 17 theses. Considering the conclusions mentioned above, the theses related to the senescence published in Korea elected different animals used for experiments, research items and the methods of research, the end result seems to be a lack of objectivity. Thus, I would argue that research methods to overcome such a deficiency need to be developed systematically.

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꼬마선충에서 메밀 추출물에 의한 산화성 스트레스 저항성 증가 및 수명 연장 효과 (Buckwheat Extract Increases Resistance to Oxidative Stress and Lifespan in Caenorhabditis elegans)

  • 김철규;박상규
    • 한국약용작물학회지
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    • 제21권1호
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    • pp.1-6
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    • 2013
  • Buckwheat (Fagopyrum esculentum) has been known for having strong anti-oxidant, anti-mutagenic, and anti-carcinogenic activities. The free radical theory of aging, also known as the oxidative stress theory of aging, claims that cellular oxidative damage accumulated with time is a major causal factor of aging. In the present study, we investigated the effect of buckwheat extracts on resistance to oxidative stress and aging using Caenorhabditis elegans as a model system. Survival under an oxidative-stress condition induced by paraquat increased markedly following 500mg/L buckwheat extracts treatment, suggesting lower cellular oxidative damage by buckwheat extracts. A lifespan assay also revealed that treatment of buckwheat extracts significantly extended both the mean and maximum lifespan in C. elegans. Interestingly, this lifespan-extension by buckwheat extracts was not accompanied by reduced fertility. These findings suggest that buckwheat extracts can confer longevity phenotype to C. elegans through its strong anti-oxidant activity and support the aging theory which emphasizes a pivotal role of oxidative stress during aging.