• Title/Summary/Keyword: Dendritic growth

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Brain-Derived Neurotrophic Factor and Brain Plasticity: Non-Pharmacological Intervention (뇌유래신경영양인자와 뇌 신경가소성: 비약물적 개입)

  • Nak-Young Kim;Hyun Kook Lim
    • Korean Journal of Biological Psychiatry
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    • v.30 no.1
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    • pp.1-6
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    • 2023
  • Many psychiatric disorders are associated with brain functional dysfunctions and neuronal degeneration. According to the research so far, enhanced brain plasticity reduces neurodegeneration and recovers neuronal damage. Brain-derived neurotrophic factor (BDNF) is one of the most extensively studied neurotrophins in the mammalian brain that plays major roles in neuronal survival, development, growth, and maintenance of neurons in brain circuits related to emotion and cognitive function. Also, BDNF plays an important role in brain plasticity, influencing dendritic spines in the hippocampus neurogenesis. Changes in neurogenesis and dendritic density can improve psychiatric symptoms and cognitive functions. BDNF has potent effects on brain plasticity through biochemical mechanisms, cellular signal pathways, and epigenetic changes. There are pharmacological and non-pharmacological interventions to increase the expression of BDNF and enhance brain plasticity. Non-pharmacological interventions such as physical exercise, nutritional change, environmental enrichment, and neuromodulation have biological mechanisms that increase the expression of BDNF and brain plasticity. Non-pharmacological interventions are cost-effective and safe ways to improve psychiatric symptoms.

A Study on Microstructure Formation during Directional Solidification of a Hypoeutectic Al-11.3Si-3.5Cu alloy (아공정 Al-11.3Si-3.5Cu 합금의 응고조직 형성거동에 관한 연구)

  • Seo, Heesik;Gu, Jiho;Park, Kyungmi;Lee, Jeongseok;Lee, Jehyun;Chung, Wonsub
    • Korean Journal of Metals and Materials
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    • v.50 no.12
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    • pp.897-905
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    • 2012
  • Directional solidification experiments were carried out in a hypoeutectic Al-11.3Si-3.5Cu system to investigate the microstructural evolution with the solidification rate. At a fixed temperature gradient, a dendritic microstructure was observed at a constant speed of more than $25{\mu}ms^{-1}$, a cellular interface developed at $5{\mu}ms^{-1}$ and the growth rate of $0.5{\mu}ms^{-1}$ led to the stability of the planar interface. The results revealed that primary silicon phases formed among cells, even though the studied Al-Si alloy system formed the composition within a hypoeutectic silicon composition. This suggests that the liquid concentration among cells during solidification reached a higher concentration, i.e., the eutectic concentration. It is, however, interesting that primary silicon phases did not form during a dendritic growth of more than $25{\mu}ms^{-1}$. These experimental observations are explained using the theoretical models on the interface temperatures.

The Effects of Echinacea Extract on the Gene Expression of Monocytes and Monocyte-derived Dendritic Cells (Echinacea 추출물이 단구와 단구유래 수지상세포의 유전자발현에 미치는 효과)

  • Park, Jun Eun;Choi, Kang Duk;Kim, Sung Hwan;Hahm, Dae-Hyun;Seo, Jong Jin
    • Clinical and Experimental Pediatrics
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    • v.48 no.7
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    • pp.779-788
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    • 2005
  • Purpose : Echinacea, a traditional plant medicine has been used as immune-stimulant. Recent studies have revealed that extract of Echinacea has immunostimulatory effects on human blood mononuclear cells. This study was designed for the purpose of screening the genes associated with immunologic effects of Echinacea on monocytes and dendritic cells using a cDNA microarray chip. Methods : $CD14^+$ monocyte cells were cultured for one day with Echinacea extract(final concentration : $50{\mu}g/mL$) in experiment 1, but were cultured without Echinacea in experiment 2. The gene expression of these cultured monocytes was analyzed using the cDNA microarray chip. Dendritic cells produced from $CD14^+$ monocyte were cultured for five days with GM-CSF and IL-4, and then cultured for one day with Echinacea in experiment 3, but were done without Echinacea in experiment 4. Results : In experiments 1 and 2, there were 17 significantly expressed genes with average expression ratios above 2.5, including interferon gamma-inducible protein 30(IFI 30), CDC(cell-division-cylcle)-like kinase 2(CLK 2), syndecan binding protein(syntenin), superoxide dismutase 2, etc. In experiments 3 and 4, there were 24 gene, with significantly expressed genes were 24 genes, which were insulin-like growth factor 2(somatomedin A), methyl-CpG binding domain protein 3, IFI 30, small inducible cytokine subfamily A, member 22, etc. The genes encoding CD44, IFI 30, mannose receptor C type 1(MRC 1), chemokine receptor 7(CCR 7), CLK 2, syntenin and cytochrome C oxidase subunit VIII were significantly expressed in both monocytes and dendritic cells cultured with Echinacea. Conclusion : This study employed a cDNA microarray chip to elicit the immune-associated gene profile; the expression was enhanced by Echinacea in CD14+ monocytes and dendritic cells. Thus we laid the basis for the quantitative and functional analysis of genes induced by Echinacea in monocytes and monocyte-derived dendritic cells.

LPS Stimulated B Lymphocytes Inhibit the Differentiation of Th1 Lymphocytes (LPS에 의해 자극된 B 림프구에 의한 Th1 림프구 분화 억제)

  • Kim, Ha-Jeong
    • Journal of Life Science
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    • v.25 no.12
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    • pp.1425-1431
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    • 2015
  • The lymphocyte component of the immune system is divided into B lymphocytes and T lymphocytes. B lymphocytes produce antibodies (humoral immunity) via maturation into plasma cells, and T lymphocytes kill other cells or organisms (cellular immunity). A traditional immunological paradigm is that B lymphocyte and T lymphocyte interactions are a one-way phenomenon, with T lymphocytes helping to induce the terminal differentiation of B lymphocytes into immunoglobulin class-switched plasma cells. A deficiency of T lymphocytes was reported to result in defective B lymphocyte function. However, evidence for a reciprocal interaction between B and T lymphocytes is emerging, with B lymphocytes influencing the differentiation and effector function of T lymphocytes. For example, B lymphocytes have been shown to induce direct tolerance of antigen-specific CD8+ T lymphocytes and induce T lymphocytes anergy via transforming growth factor-beta (TGF-β) production. The present study showed that LPS-stimulated B lymphocytes inhibited the differentiation of Th1 lymphocytes by inhibiting the production of interleukin-12 (IL-12) from dendritic cells. An interaction between the B lymphocytes and dendritic cells was not needed for this inhibition, and the B lymphocytes did not alter dendritic cell maturation. B lymphocyte-derived soluble factor (BDSF) suppressed the LPS-induced IL-12p35 transcription in the dendritic cells. Overall, these results point to a novel B lymphocyte- mediated immune suppressive mechanism. The findings cast doubt on the traditional paradigm of immunological interactions involving B lymphocyte and T lymphocyte interactions.

Effects of Woohwangcheongsim-won on Gene Expression in a Hypoxic Model of Cultured Rat Cortical Cells (배양한 흰쥐 대뇌세포의 저산소증 모델에서 우황청심원이 유전자 표현에 미치는 영향)

  • Park Dong-Wan;Kim Wan-Sik;Bae Cheol-hwan;Jeong Sung-Hyun;Shin Gil-Cho;Lee Won-Chul
    • The Journal of Korean Medicine
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    • v.25 no.3
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    • pp.123-136
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    • 2004
  • Objectives : The purpose of this investigation is to evaluate the effects of Woohwangcheongsim-won (WC) on the in vitro neuronal development and alteration in gene expression in a hypoxia model using cultured rat cortical cells. Methods : E/sub 18/ rat cortical cells were grown in a neurobasal medium containing B27 supplement and various concentration of WC. Initial development of growth cone was investigated by phase-contrast microscopy, while dendritic spine formation and synaptogenesis were investigated by immunocytochemistry with SynGAPα(a postsynaptic marker) and synaptophysin (presynaptic marker) antibodies. Alteration in gene expression was analyses by microarray using rat 5K-TwinChips. Results : WC suppressed the development of growth cones and WC increased the number of dendritic spines at 20 and 50㎍/mL concentration but there was no statistical significance. Instead, it significantly decreased the number at 100㎍/mL. The expression of anti-apoptosis gene Bcl2-like 1 (Bcl211) increased (Global M=0.46), while Akt1 decreased. Proapoptosis genes Bad and PDCD2 increased. The expression of hemoglobin alpha 1 (probably neuroglobin) increased (Global M=0.93). The expression of antioxidants such as catalase, heme oxygenase (HO), and PRKAG2 gene increased. The expression PKC gene increased. The expression of retinoic acid receptor alpha (RARα) increased significantly (Global M=1.0). Conclusions : These data suggest that WC trends to suppress cellular activity slightly in normoxia and increases the expression of apoptosis-, antioxidation-, oxygen capture-related genes in hypoxia, but increases Bcl111 that anti-apoptosis gene, on the other hand increases Bad, PDCD2 that pro-apoptosis genes, too..

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Synergistic Anti-Tumor Effect by the Combination of Cyclophosphamide and Dendritic Cell Vaccination in Murine Tumor Model that CEA Expressing (CEA 발현 마우스 종양모델에서 Cyclophosphamide와 수지상세포 백신의 병합치료에 의한 상승적인 항종양 효과)

  • Park, Mi-Young
    • Korean Journal of Clinical Laboratory Science
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    • v.54 no.1
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    • pp.38-48
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    • 2022
  • Carcinoembryonic antigen (CEA) is an oncofetal antigen primarily detected in the peripheral blood of cancer patients, particularly in those with colorectal cancer. CEA is considered a valuable target for antigen-specific immunotherapy. In this study, we induced the anti-tumor immunity for CEA through the administration of a dendritic cell (DC) vaccine. However, there was a limitation in inducing tumor regression in the DC vaccinated mice. To enhance the efficacy of anti-tumor immunity in MC38/CEA2 tumor-bearing mice, we evaluated the effects of DC vaccine in combination with cyclophosphamide (CYP). Administration of CYP 100 mg/kg in mice resulted in significant inhibition of tumor growth in the 2-day tumor model, whereas a lower inhibition of tumor growth was seen in the 10-day tumor model. Therefore, the 10-day tumor model was selected for testing chemo-immunotherapy. The combined CYP and DC vaccine not only increased tumor antigen-specific immune responses but also induced synergistic anti-tumor immunity. Furthermore, the adverse effects of CYP such as weight loss and immunosuppression by regulatory T cells and myeloid-derived suppressor cells showed a significant reduction in the combined chemo-immunotherapy treatment compared with CYP alone. Our data suggest that chemoimmunotherapy with the DC vaccine may offer a new therapeutic strategy to induce a potent anti-tumor effect and reduce the adverse effects of chemotherapy.

Numerical Simulation of Dendritic Growth of the Multiple Seeds with Fluid Flow (유체 유동을 동반한 다핵 수치상결정의 미세구조성장에 대한 수치해석적 연구)

  • Yoon, Ik-Roh;Shin, Seung-Won
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.33 no.7
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    • pp.469-476
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    • 2009
  • Most material of engineering interest undergoes solidification process from liquid state. Identifying the underlying mechanism during solidification process is essential to determine the microstructure of material thus the physical properties of final product. In this paper, effect of fluid convection on the dendrite solidification morphology is studied using Level Contour Reconstruction Method. Sharp interface technique is used to implement correct boundary condition for moving solid interface. The results showed good agreement with exact boundary integral solution and compared well with other numerical techniques. Effects of Peclet number and undercooling on growth of dendrite tip of both single and multiple seeds have been also investigated.

Effects of Hydrostatic Pressure on Solidification Phenomena of Al-Si binary alloys(I);Metallurgical Study (Al-Si이원계 합금의 응고현상에 미치는 정수압의 영향(I);금속 조직적 연구)

  • Han, Y.S.;Kim, D.H.;Lee, H.I.
    • Journal of Korea Foundry Society
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    • v.6 no.2
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    • pp.116-121
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    • 1986
  • The effects of pressure during solidification on macro-and micro-structures have been studied in pure aluminium and Al-Si alloys. The application of pressure during solidifcation accelerated both equiaxed and columnar dendritic-growth due to stimulating of equiaxed survival and faster preferential growth of primary dendrites against the parallel direction of heat flow. Burden-Hunt model was modified to express the significant changes of CET behaviours under pressure. A further point to be noted was that greatly fine eutectic silicon flakes ($0.5\;{\times}\;13{\mu}m$) with the decrease of halo layers ($7{\mu}m$) of aluminium riched phases in the periphery of primary silicon particles were observed when pressure was applied during solidification.

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Study on the Phase Interface Tracking Numerical Schemes by Level Set Method (Level Set 방법에 의한 상경계 추적 수치기법 연구)

  • Kim, Won-Kap;Chung, Jae-Dong
    • Proceedings of the SAREK Conference
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    • 2006.06a
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    • pp.116-121
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    • 2006
  • Numerical simulations for dendritic growth of crystals are conducted in this study by the level set method. The effect of order of difference is tested for reinitialization error in simple problems and authors founded in case of 1st order of difference that very fine grids have to be used to minimize the error and higher order of difference is desirable to minimize the reinitialization error The 2nd and 4th order Runge-Kutta scheme in time and 3rd and 5th order of WENO schemes with Godunov scheme are applied for space discretization. Numerical results are compared with the analytical theory, phase-field method and other researcher's level set method.

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Morphology of Methane/Propane Clathrate Hydrate Crystal (메탄/프로판 포접 하이드레이트 결정의 성장 특성)

  • Lee, Ju Dong;Englezos, Peter;Yoon, Yong Seok;Song, Myungho
    • Korean Chemical Engineering Research
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    • v.45 no.4
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    • pp.400-409
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    • 2007
  • Morphology of methane/propane clathrate hydrate crystal was investigated under different undercooling conditions. After the water pressurized with compound guest gas was fully saturated by agitation, medium within the vessel was rapidly undercooled and maintained at the constant temperature while the visual observations using microscope revealed detailed features of subsequent crystal nucleation, migration, growth and interference occurring within liquid pool. The growth of hydrate was always initiated with film formations at the bounding surface between bulk gas and liquid regions under all tested experimental conditions. Then a number of small crystals ascended, some of which settled beneath the hydrate film. When undercooling was relatively small, some of the settled crystals slowly grew into faceted columns. As the undercooling increased, the downward growth of crystals underneath the hydrate film became dendritic and occurred with greater rate and with finer arm spacing. The shapes of the floating crystals within liquid pool were diverse and included octahedron and triangular or hexagonal platelet. When the undercooling was small, the octahedral crystals were found dominant. As the undercooling increased, the shape of the floating crystals also became dendritic. The detailed growth characteristics of floating crystals are reported focused on the influences caused by undercooling and memory effect.