• 제목/요약/키워드: growth modification

검색결과 347건 처리시간 0.023초

전기-경련 시술후의 혈장 HGH 반응 (A Study on the Human Growth Hormone Response Following Electro Convulsion Therapy)

  • 김동주;성호경;이상돈
    • The Korean Journal of Physiology
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    • 제10권1호
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    • pp.67-71
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    • 1976
  • Effect of Electro Convulsion Therapy (ECT) on the Human Growth Hormone (HGH) response was observed in 32 cases of various mental illness. The patients were fasting overnight and ECT was induced in the morning by application of $90{\sim}120V$ for a period of $0.1{\sim}0.5\;sec$. In all patients, venous blood samples were taken prior to simultaneously with 1 and 4 hours after the ECT. Plasma was immediately seperated and stored in $-20^{\circ}C$ refrigerator. HGH concentrantion was determined by means of radioimmunoassay Results were as follows: 1. Application of electric current was not followed by a significant change in mean plasma HGH of 52 cases. 2 Increases of plasma HGH following ECT were observed in about half cases showing low initial level but in 20 other cases with high initial level of plasma HGH, reasonable decreases after therapy were not found. 3. Plasma concentration of HGH one hour after application of current were always higher than just after the current. 4. There were no differences between HGH responses to a 1st, 2nd or 5th ECT. 5. Discussions were made on the possible modification of HGH response following ECT by the autoregulatory control mechanism.

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Ethyl Silicate를 이용한 고순도 $\beta$-SiC미분말 합성에 관한 연구(II) (분말의 특성, 반응형식 및 활성화에너지) (A Studyon Synthesis of High Purity $\beta$-SiC Fine Particles from Ethyl Silicate(II) (Powder Properties, Reaction Type and Activation Energy))

  • 최용식;박금철
    • 한국세라믹학회지
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    • 제26권2호
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    • pp.195-200
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    • 1989
  • The Silica-Carbon mixture was made with addition of carbon black in the composition which monodispersed spherical fine silica was formed by the hydrolysis of ethylsilicate, mole ratio of Carbon/Alkoxide was 3.1 and $\beta$-SiC powder was synthesized by reacting this mixture at 1,350~1,50$0^{\circ}C$ in Ar atmosphere. The results of this study are as follow : (1) The purity of synthesized $\beta$-SiC powder was above 99.98% and it was in cubic modification with lattice constant of 4.3476$\AA$. (2) The rate-controlling steps varied with the reaction temperature for the syntehsis of $\beta$-SiC in this study ; nucleation and growth of $\beta$-SiC at 1,350~1,40$0^{\circ}C$, interfacial reaction at 1,45$0^{\circ}C$ and diffusion described by Jander Equation at 1,50$0^{\circ}C$. (3) When the rate-determining step was nucleation and growth, the activation energy was about 87.8kcal/mol.

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Enhanced Expression of High-affinity Iron Transporters via H-ferritin Production in Yeast

  • Kim, Kyung-Suk;Chang, Yu-Jung;Chung, Yun-Jo;Park, Chung-Ung;Seo, Hyang-Yim
    • BMB Reports
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    • 제40권1호
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    • pp.82-87
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    • 2007
  • Our heterologous expression system of the human ferritin H-chain gene (hfH) allowed us to characterize the cellular effects of ferritin in yeasts. The recombinant Saccharomyces cerevisiae (YGH2) evidenced impaired growth as compared to the control, which was correlated with ferritin expression and with the formation of core minerals. Growth was recovered via the administration of iron supplements. The modification of cellular iron metabolism, which involved the increased expression of high-affinity iron transport genes (FET3 and FTR1), was detected via Northern blot analysis. The findings may provide some evidence of cytosolic iron deficiency, as the genes were expressed transcriptionally under iron-deficient conditions. According to our results examining reactive oxygen species (ROS) generation via the fluorescence method, the ROS levels in YGH2 were decreased compared to the control. It suggests that the expression of active H-ferritins reduced the content of free iron in yeast. Therefore, present results may provide new insights into the regulatory network and pathways inherent to iron depletion conditions.

Aspergillus phoenicis를 이용한 steroid의 변형 (Steroid modification with aspergillus phoenices)

  • 김말남;이영종
    • 미생물학회지
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    • 제23권4호
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    • pp.297-301
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    • 1985
  • The dependence of activities of Aspergillus phoenicis on the culture conditions in the progesterone transformation reaction was investigated. In the beginning of the reaction, $6{\beta},\;11{\alpha}-dihydroxyprogesterone$ was not produced even at high concentration of $11{\alpha}-hydroxyprogesterone$. However, large amount of the product was obtained after the complete exhaustion of progesterone. When spores of A.phoenicis replaced mycelia as enzyme source, $11{\alpha}-hydroxyprogesterone$ was produced after a considerably long indyction period, and its maximum production rate followed the exponential growth phase. The $6{\beta}-hydroxylation\;of\;11{\alpha}-hydroxyprogesterone$ continued, even after the stationary growth phase. A. phoenicis showed high enzyme activity for these reactions when the phosphate buffer solutions were used in place of the ordinary culture medium. The buffer solutions of low pH gave more yield of $11{\alpha}-hydroxyprogesterone$ than those of high pH. However, the addition of flucose to the buffer solutions did not activate the transformation reaction. The presence of progesterone seems to be necessary for the induction of enzymes for the $6{\beta}-hydroxylation\;of\;11{\alpha}-hydroxyprogesterone\;since\;6{\beta},\;11{\alpha}-dihydroxyprogesterone$ is not produced in the reaction medium containing only $11{\alpha}-hydroxyprogesterone$ as a substrate.

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ECAP 강가공에 의한 마그네슘 AZ31합금의 결정립 미세화 및 미세조직 불안정성 (Grain Refinement and Microstructural Instability of an AZ31 Mg Alloy by Severe Plastic Deformation Using ECA Pressing)

  • 김호경;정강;현창용
    • 열처리공학회지
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    • 제17권3호
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    • pp.139-145
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    • 2004
  • Equal channel angular pressing (ECAP) technique had been adapted to the Mg alloy (AZ31) for achieving effective grain refinement through severe deformation. The average grain size of $2.5{\mu}m$ could be obtained after 4 passes. The stability of the ECAPed structure at elevated temperatures was examined by annealing the ECAPed materials over a wide range of temperature between 473 and 748 K. The average activation energy, Q, for static grain growth of 1, 2 and 3 passes was 33.7 kJ/mole (=0.25QL, activation for lattice diffusion). The abnormally low Q value in the lower temperature range may indicate that grain growth occurs in the unrecrystallized microstructure where non-equilibrium grain boundaries containing a large number of extrinsic dislocations exist. The yield stresses of the ECAPed alloys decreased whereas the elongations increased after the ECAP process. These results should be related to the modification of texture for easier slip on basal plane.

A Cohesive Surface Separation Potential

  • Lee, Youngseog;Kim, Kwang-Soo
    • Journal of Mechanical Science and Technology
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    • 제16권11호
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    • pp.1435-1439
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    • 2002
  • This paper presents a form of the cohesive surface separation potential, which can produce potential curves by varying a single dimensionless parameter. Results show that a partial modification of Xu and Needleman's (1994) cohesive surface separation potential makes it possible to present the other potential corves as a special case as long as the normal separation is concerned. The proposed potential may describe interfacial debonding-crack initiation and growth-character of materials and, through numerical simulation, provide an insight for the effect of different cohesive surface separation potentials on the interfacial debonding.

AI 5182 합금 판재의 회전압연 집합조직과 미세조직 (Clock Rolling texture and Microstructure in AA5182)

  • 마종완;이강노;김훈동;허무영
    • 한국소성가공학회:학술대회논문집
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    • 한국소성가공학회 2001년도 추계학술대회 논문집
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    • pp.147-149
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    • 2001
  • In order to understand the influence of the modification of deformation texture on the formation of annealing texture, the evolution of texture during the clock rolling and the subsequent annealing was investigated by employing X-ray texture measurements and microstructure observation. The $\beta$-fiber orientations were proved to be quite unstable during the clock rolling. The clock rolled texture having uniform orientation densities along $\{011\}//ND$ fiber resulted in the randomization of annealing texture. This indicated that the operation of both the oriented nucleation and the oriented growth was effectively suppressed in the clock-rolled specimen during recrystallization.

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회전속도 증가에 의한 광디스크의 파괴현상에 관한 연구 (A Study on the Fracture Phenomena in Optical Disks Due to Increase of the Rotating Speed)

  • 조은형;좌성훈;정진태
    • 소음진동
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    • 제11권3호
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    • pp.437-442
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    • 2001
  • In this study, the fracture phenomena of optical disks are discussed by theoretical and experimental approaches and then some recommendations are presented to prevent the fracture. Linear equations of motion are discretized by using the Galerkin approximation. From the discretized equations, the dynamic responses are computed by the generalized- time integration method. As a fracture criterion for optical disks, the critical crack length is presented. From experimental methods, the fracture procedure is analyzed. The fracture occurs when disks have crack on the inner radius of the disks. Since the crack growth and the fracture result from the stress concentration on the tip of the crack, a measure should be taken to overcome the stress concentration. This problem can be resolved by the structural modification of a disk. This study proposes 3 types of improved optical disks.

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Characteristics of 14-3-3 Proteins and Their Role in Plant Immunity

  • Oh, Chang-Sik
    • The Plant Pathology Journal
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    • 제26권1호
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    • pp.1-7
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    • 2010
  • Phosphorylation is a major post-translational modification of proteins that regulate diverse signal transduction pathways in eukaryotic cells. 14-3-3 proteins are regulatory proteins that bind to target proteins in a phosphorylation-dependent manner and have been shown to play an important role in plant growth and development, primary metabolism, and signal transduction. Because phosphorylation plays a critical role in signal transduction pathways to trigger plant immunity, involvement of 14-3-3 proteins in plant immunity has been suggested for a long time. Recent studies have provided new evidence to support a role for 14-3-3 proteins in plant immunity. This review will briefly discuss general characteristics of 14-3-3 proteins and their involvement in plant immunity.