• 제목/요약/키워드: Dendritic

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The effect of process parameters on copper powder particle size and shape produced by electrolysis method

  • Boz, Mustafa;Hasheminiasari, Masood
    • Steel and Composite Structures
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    • 제15권2호
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    • pp.151-162
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    • 2013
  • In this study, an electrolyzing device for the production of metal powders was designed and fabricated. The production of copper powders was performed using a variety of current densities, anode-cathode distances and power removal times. The effect of these parameters on powder particle size and shape was determined. Particle size was measured using a laser diffraction unit while the powder shape was determined by SEM. Experimental results show that an increase in current density leads to a decrease in powder particle size. In addition particle shape changed from globular dendritic to acicular dendritic with increasing the current density. Distance between the cathode and anode also showed a similar influence on powder particle size and shape. An increase in time of powder removal led to an increase in powder particle size, as the shape changed from acicular dendritic to globular dendritic.

Self-Assembly of Helical Pores from Nonpolar Dendritic Dipeptides

  • Percec, Virgil
    • 한국고분자학회:학술대회논문집
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    • 한국고분자학회 2006년도 IUPAC International Symposium on Advanced Polymers for Emerging Technologies
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    • pp.29-30
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    • 2006
  • The synthesis of dendritic dipeptides $(4-3,4-3,5)12G2-CH_{2}-Boc-_{L}-Tyr-X-OMe\;where\;X\;=\;Gly,\;_{L}-Val,\;_{L}-Leu,\;_{L}-Ile,\;_{L}-Phe$, and L-Pro will be discussed. Their self-assembly in bulk and in solution and the structural and retrostructural analysis of their periodic assemblies will be compared to that of the previously reported and currently reinvestigated dendritic dipeptide with $X=_{L}-Ala$. All dendritic dipeptides containing as X nonpolar ${\alpha}-amino$ acids self-assemble into helical porous columns. The principles via which the aliphatic and aromatic substituents of X program the structure of the helical pores indicate synthetic pathways to helical pores with bioinspired functions based on artificial nonpolar ${\alpha}-amino$ acids will be discussed.

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Effect of Particles Drift on Dendritic Growth

  • Park, Min Sik;Im, Dongmin
    • Journal of Electrochemical Science and Technology
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    • 제5권2호
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    • pp.53-57
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    • 2014
  • With the use of diffusion-limited aggregation modeling, we have investigated the effect of particle drift for dendritic growth. It is found that the morphology of dendritic growth is sensitive to the particle drift, i.e., the larger drift effect results in the denser growth of dendrite. From the analysis using the correlation function, we found the fractional dimension of each dendrite increases as the particles drift increases. Furthermore, we showed the height of dendrite significantly decrease for the slight change of particles drift. Finally, we discussed the strategy to reduce dendritic growth by modifying the transport properties of electrolytes.

Expression of TNF-${\alpha}$ and IL-$1{\beta}$ in Splenic Dendritic Cells and Their Serum Levels in Mouse Sparganosis

  • Yang, Hyun-Jong
    • Parasites, Hosts and Diseases
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    • 제49권2호
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    • pp.191-194
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    • 2011
  • Sparganosis is a tissue invading helminthiasis infecting intermediate hosts, including humans. Strong immune responses are expected to occur in early phases of infection. Thus, we investigated cytokine expressions in splenic dendritic cells and in sera after experimental infection of mice. In splenic dendritic cells, TNF-${\alpha}$ and IL-$1{\beta}$ expression peaked at week 1 and week 3 post -infection (PI), respectively, and also early phase (week 2 PI) depressed cytokine expression was noticed. Serum IL-$1{\beta}$ concentration increased significantly at week 2 PI and peaked at week 6 PI, and that of TNF-${\alpha}$ peaked at week 6 PI. These results showed that pro-inflammatory cytokines, TNF-${\alpha}$ and IL-$1{\beta}$, are chronologically regulated in mouse sparganosis.

피부의 수상돌기 세포 ((Dendritic cells in the skin))

  • 이민걸
    • 대한화장품학회지
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    • 제25권2호
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    • pp.35-44
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    • 1999
  • 수상돌기 세포는 인체의 1차 면역반응을 일으키는 가장 강력한 항원 전달세포이다. 피부의 수상돌기 세포에는 표피의 랑게르한스 세포와 진피의 수상돌기 세포가 있으며, 이중 표피의 랑게르한스 세포에 관한 많은 연구가 이루어져 있다. 암, 자가면역 질환, 장기이식, 감염 등의 면역 반응에 가장 중요한 항원 전달 세포인 수상돌기 세포의 이해에 표피의 랑게르한스 세포가 중요한 역할을 하였다. 본 논문에서는 피부질환 중 알레르기성 접촉 피부염과 아토피성 피부염에서 랑게르한스 세포의 역할에 관하여 최근 알려진 사실들을 기초로 기술하였다. 그리고 랑게르한스 세포연구에 필요한 실험 방법을 간단히 기술하였다

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Immuno-modulation effects of cefodizime, a cephalosporin, in rat dendritic cells

  • Joo, Seong-Soo;Won, Tae-Joon;Lee, Do-Ik
    • 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.129.1-129.1
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    • 2003
  • According to recent reports, cefodizime (CEF), a third generation cephalosporin has the capability of chemotactic activity of neutrophils and monocytes and may act as the strong immuno-modulator. This study was planned to demonstrate whether CEF has the proposed effect on rat dendritic cells in vitro. Dendritic cells were taken from rat spleen tissue and cultured for a week. The obtained dendritic cells were treated with 10$\mu$g/ml, 50$\mu$g/ml, 100$\mu$g/ml cefodizime and 10IU/$m\ell$ IFN-Υ+1$\mu$g/ml LPS. (omitted)

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Resveratrol regulates naïve CD 8+ T-cell proliferation by upregulating IFN-γ-induced tryptophanyl-tRNA synthetase expression

  • Noh, Kyung Tae;Cho, Joon;Chun, Sung Hak;Jang, Jong-Hwa;Cha, Gil Sun;Jung, In Duk;Jang, Dong Deuk;Park, Yeong-Min
    • BMB Reports
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    • 제48권5호
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    • pp.283-288
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    • 2015
  • We found that resveratrol enhances interferon (IFN)-γ-induced tryptophanyl-tRNA-synthetase (TTS) expression in bone marrow-derived dendritic cells (BMDCs). Resveratrol-induced TTS expression is associated with glycogen synthase kinase-3β (GSK-3β) activity. In addition, we found that resveratrol regulates naive CD8+ T-cell polarization by modulating GSK-3β activity in IFN-γ-stimulated BMDCs, and that resveratol induces upregulation of TTS in CD8+ T-cells in the in vivo tumor environment. Taken together, resveratrol upregulates IFN-γ-induced TTS expression in a GSK-3β-dependent manner, and this TTS modulation is crucial for DC-mediated T-cell modulation. [BMB Reports 2015; 48(5): 283-288]

수지형 하천에서의 부정류 흐름의 해석 알고리즘 (Solution Algorithm of Unsteady Flow in a Dendritic Channel System)

  • 최계운
    • 대한토목학회논문집
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    • 제14권4호
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    • pp.839-846
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    • 1994
  • 본 논문에서 수지형 하천내 1차원 부정류 흐름해석을 위한 알고리즘을 개발하였다. 이 해석 알고리즘은 수지형 하천내 부정류의 흐름을 각각의 지류내 단면간에는 연속방정식과 모우멘트 방정식을 적용하고 합류점과 분류점에서는 연속방정식과 에너지방정식을 적용하여 유한차분화한후, 이에 적합한 순환방정식을 도출하여 적용하였으며, 이때 순환계수들은 합류하는 하천단면, 분류하는 하천단변, 합류점, 분류정에 따라 각각 다르게 결정토록 하였다. 이와같은 순환계수 및 순환방정식을 이용하여 수지형 하천내 흐름해석을 단일 하천내 흐름해석과 동일하게 전진법에서는 순환계수를 계산하고, 후진법에서는 순환방정식의 해를 구하는 것이 가능하도록 하였다. 이에 따라 흐름해석을 위한 컴퓨터 저장용량도 $2N{\times}2N$ 행렬로부터 $2N{\times}4$ 행렬로 줄이도록 하였고 계산시간도 상당히 절약하였으며 이때 N은 수지형 하천내 흐름특성인 유량 및 수위를 결정해야하는 절점을 나타낸다. 이와같이 제안된 알고리즘을 이용하여 수지형 하천내 부정류 흐름을 개인용 컴퓨터등을 이용하여 효율적이며 정확하게 해석할 수 있다.

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Imipramine Ameliorates Depressive Symptoms by Blocking Differential Alteration of Dendritic Spine Structure in Amygdala and Prefrontal Cortex of Chronic Stress-Induced Mice

  • Leem, Yea-Hyun;Yoon, Sang-Sun;Jo, Sangmee Ahn
    • Biomolecules & Therapeutics
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    • 제28권3호
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    • pp.230-239
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    • 2020
  • Previous studies have shown disrupted synaptic plasticity and neural activity in depression. Such alteration is strongly associated with disrupted synaptic structures. Chronic stress has been known to induce changes in dendritic structure in the basolateral amygdala (BLA) and medial prefrontal cortex (mPFC), but antidepressant effect on structure of these brain areas has been unclear. Here, the effects of imipramine on dendritic spine density and morphology in BLA and mPFC subregions of stressed mice were examined. Chronic restraint stress caused depressive-like behaviors such as enhanced social avoidance and despair level coincident with differential changes in dendritic spine structure. Chronic stress enhanced dendritic spine density in the lateral nucleus of BLA with no significant change in the basal nucleus of BLA, and altered the proportion of stubby or mushroom spines in both subregions. Conversely, in the apical and basal mPFC, chronic stress caused a significant reduction in spine density. The proportion of stubby or mushroom spines in these subregions overall reduced while the proportion of thin spines increased after repeated stress. Interestingly, most of these structural alterations by chronic stress were reversed by imipramine. In addition, structural changes caused by stress and blocking the changes by imipramine were corelated well with altered activation and expression of synaptic plasticity-promoting molecules such as phospho-CREB, phospho-CAMKII, and PSD-95. Collectively, our data suggest that imipramine modulates stress-induced changes in synaptic structure and synaptic plasticity-promoting molecules in a coordinated manner although structural and molecular alterations induced by stress are distinct in the BLA and mPFC.