• Title/Summary/Keyword: cell morphology

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Recent Developments of Metal-N-C Catalysts Toward Oxygen Reduction Reaction for Anion Exchange Membrane Fuel Cell: A Review

  • Jong Gyeong Kim;Youngin Cho;Chanho Pak
    • Journal of Electrochemical Science and Technology
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    • v.15 no.2
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    • pp.207-219
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    • 2024
  • Metal-N-C (MNC) catalysts have been anticipated as promising candidates for oxygen reduction reaction (ORR) to achieve low-cost polymer electrolyte membrane fuel cells. The structure of the M-Nx moiety enabled a high catalytic activity that was not observed in previously reported transition metal nanoparticle-based catalysts. Despite progress in non-precious metal catalysts, the low density of active sites of MNCs, which resulted in lower single-cell performance than Pt/C, needs to be resolved for practical application. This review focused on the recent studies and methodologies aimed to overcome these limitations and develop an inexpensive catalyst with excellent activity and durability in an alkaline environment. It included the possibility of non-precious metals as active materials for ORR catalysts, starting from Co phthalocyanine as ORR catalyst and the development of methodologies (e.g., metal-coordinated N-containing polymers, metal-organic frameworks) to form active sites, M-Nx moieties. Thereafter, the motivation, procedures, and progress of the latest research on the design of catalyst morphology for improved mass transport ability and active site engineering that allowed the promoted ORR kinetics were discussed.

Gintonin influences the morphology and motility of adult brain neurons via LPA receptors

  • Kim, Do-Geun;Kim, Hyeon-Joong;Choi, Sun-Hye;Nam, Sung Min;Kim, Hyoung-Chun;Rhim, Hyewhon;Cho, Ik-Hyun;Rhee, Man Hee;Nah, Seung-Yeol
    • Journal of Ginseng Research
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    • v.45 no.3
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    • pp.401-407
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    • 2021
  • Background: Gintonin is an exogenous ginseng-derived G-protein-coupled lysophosphatidic acid (LPA) receptor ligand. LPA induces in vitro morphological changes and migration through neuronal LPA1 receptor. Recently, we reported that systemic administration of gintonin increases blood-brain barrier (BBB) permeability via the paracellular pathway and its binding to brain neurons. However, little is known about the influences of gintonin on in vivo neuron morphology and migration in the brain. Materials and methods: We examined the effects of gintonin on in vitro migration and morphology using primary hippocampal neural precursor cells (hNPC) and in vivo effects of gintonin on adult brain neurons using real time microscopic analysis and immunohistochemical analysis to observe the morphological and locational changes induced by gintonin treatment. Results: We found that treating hNPCs with gintonin induced morphological changes with a cell rounding following cell aggregation and return to individual neurons with time relapses. However, the in vitro effects of gintonin on hNPCs were blocked by the LPA1/3 receptor antagonist, Ki16425, and Rho kinase inhibitor, Y27632. We also examined the in vivo effects of gintonin on the morphological changes and migration of neurons in adult mouse brains using anti-NeuN and -neurofilament H antibodies. We found that acute intravenous administration of gintonin induced morphological and migrational changes in brain neurons. Gintonin induced some migrations of neurons with shortened neurofilament H in the cortex. The in vivo effects of gintonin were also blocked by Ki16425. Conclusion: The present report raises the possibility that gintonin could enter the brain and exert its influences on the migration and morphology of adult mouse brain neurons and possibly explains the therapeutic effects of neurological diseases behind the gintonin administration.

Effect of the polyols and blowing agents on properties of rigid polyurethane foam (폴리올과 발포제에 따른 경질 폴리우레탄 폼의 물성 변화 연구)

  • Kim S. B.;Son Y. J.;Kim Y H.;Lee Y B.;Choi S. H.;Choe K. H.;Kim W. N.
    • Journal of the Korean Institute of Gas
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    • v.5 no.4 s.16
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    • pp.79-84
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    • 2001
  • In this study, the effect of polyol structure(OH-value, functionality) on the reactivity, mechanical property and cell morphology of polyurethane foam and the possibility of replacing HFC-36smfc was examined by evaluating how each blowing agent(CFC-11, HCFC-l4lb, HFC-36smfc) affects the reactivity, mechanical property and cell morphology. Results of the experiment showed that as the functionality and OH-value of polyol increased, there was an increase in the temperature profile, reaction rate, density and compressive strength. However. as the functionality and OH-value increased. the ceil size became smaller The use of different kinds of blowing agents did not appear to have and significant influence on the temperature profile, reaction rate, density and compressive strength. The foam using HFC-365mfc produced more uniform cells compared to the foam using HCFC-l4lb.

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Effect of irradiation on the Streptococcus mutans (방사선조사가 Streptococcus mutans에 미치는 영향)

  • Ahn, Ki-Dong;Kim, Gyu-Tae;Choi, Yong-Suk;Hwang, Eui-Hwan
    • Imaging Science in Dentistry
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    • v.37 no.1
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    • pp.35-43
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    • 2007
  • Purpose : To observe direct effect of irradiation on cariogenic Streptooccus mutans. Materials and Methods : S. mutans GS5 was exposed to irradiation with a single absorbed dose of 10, 20, 30, and 40Gy. Viability and changes in antibiotic sensitivity, morphology, transcription of virulence factors, and protein profile of bacterium after irradiation were examined by pour plate, disc diffusion method, transmission electron microscopy, RT-PCR, and SDS-PAGE, respectively. Results : After irradiation with 10 and 20Gy, viability of S. mutans was reduced. Further increase in irradiation dose, however, did not affect the viability of the remaining cells of S. mutans. Irradiated 5. mutans was found to have become sensitive to antibiotics. In particular, the bacterium irradiated with 40Gy increased its susceptibility to cefotaxime, penicillin, and tetracycline. Under the transmission electron microscope, number of morphologically abnormal cells was increased as the irradiation dose was increased. S. mutans irradiated with 10 Gy revealed a change in the cell wall and cell membrane. As irradiation dose was increased, a higher number of cells showed thickened cell wall and cell membrane and Iysis, and appearance of ghost cells was noticeable. In RT-PCR, no difference was detected in expression of gtfB and spap between cells with and without irradiation of 40Gy. In SDS-PAGE, proteins with higher molecular masses were gradually diminished as irradiation dose was increased. Conclusion : These results suggest that irradiation affects the cell Integrity of S. mutans, as observed by SDS-PAGE, and as manifested by the change in cell morphology, antibiotic sensitivity, and eventually viability of the bacterium.

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Construction of Artificial Epithelial Tissues Prepared from Human Normal Fibroblasts and C9 Cervical Epithelial Cancer Cells Carrying Human Papillomavirus Type 18 Genes

  • Eun Kyung Yang;Seu
    • Biotechnology and Bioprocess Engineering:BBE
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    • v.3 no.1
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    • pp.1-5
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    • 1998
  • One cervical cancer cell line, C9, carrying human papillomavirus type 18 (HPV18) genes that is one of the major etiologic concoviruses for cervical cancer was characterized. This cell line was further characterized for its capacity related to the epithelial cell proliferation, stratification and differentiation in reconstituted artificial epithelial tissue. The in vitro construction of three dimensional artificial cervical opithelial tissue has been engineered using C9 epithelial cancer cells, human foreskin fibroblasts and a matrix made of type I collagen by organotypic culture of epithelial cells. The morphology of paraffin embedded artificial tissue was examined by histochemical staining. The artificial epithelial tissues were well developed having multilayer. However, the tissue morphology was similar to the cervical tissus having displasia induced by HPV infection. The characteristics of the artificial tissues were examined by determinining the expression of specific marker proteins. In the C9 derived artificial tissues, the expression of EGF receptor, as epithelial proliferation marker proteins for stratum basale was observed up to the stratum spinosum. Another epithelial proliferation marker for stratum spinosum, cytokerations 5/6/18, were observed well over the stratum spinosum. For the differentiation markers, the expression of involucrin and filaggrin were observed while the terminal differentiation marker, cytokeratins 10/13 was not detected at all. Therefore the reconstituted artificial epithelial tissues expressed the same types of differentiation marker proteins that are expressed in normal human cervical epithelial tissues but lacked the final differentiation capacity representing characteristics of C9 cell line as a cancer tissue devived cell line. Expression of HPV18 E6 oncoprotein was also observed in this artifical cervical opithelial tissue though the intensity of the staining was weak. Thus this artificial epithelial tissue could be used as a useful model system to examine the relationship between HPV-induced cervical oncogenesis and epithelial cell differentiation.

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Parallelization of Cell Contour Line Extraction Algorithm (세포 외곽선 추출 알고리즘의 병렬화)

  • Lee, Ho Seok;Yu, Suk Hyun;Kwon, Hee Yong
    • Journal of Korea Multimedia Society
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    • v.18 no.10
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    • pp.1180-1188
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    • 2015
  • In this paper, a parallel cell contour line extraction algorithm using CUDA, which has no inner contour lines, is proposed. The contour of a cell is very important in a cell image analysis. It could be obtained by a conventional serial contour tracing algorithm or parallel morphology operation. However, the cell image has various damages in acquisition or dyeing process. They could be turn into several inner contours, which make a cell image analysis difficult. The proposed algorithm introduces a min-max coordinates table into each CUDA thread block, and removes the inner contour in parallel. It is 4.1 to 7.6 times faster than a conventional serial contour tracing algorithm.

Cytotoxicity Assessments of Portulaca oleracea and Petroselinum sativum Seed Extracts on Human Hepatocellular Carcinoma Cells (HepG2)

  • Farshori, Nida Nayyar;Al-Sheddi, Ebtesam Saad;Al-Oqail, Mai Mohammad;Musarrat, Javed;Al-Khedhairy, Abdulaziz Ali;Siddiqui, Maqsood Ahmed
    • Asian Pacific Journal of Cancer Prevention
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    • v.15 no.16
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    • pp.6633-6638
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    • 2014
  • The Pharmacological potential, such as antioxidant, anti-inflammatory, and antibacterial activities of Portulaca oleracea (PO) and Petroselinum sativum (PS) extracts are well known. However, the preventive properties against hepatocellular carcinoma cells have not been explored so far. Therefore, the present investigation was designed to study the anticancer activity of seed extracts of PO and PS on the human hepatocellular carcinoma cells (HepG2). The HepG2 cells were exposed with $5-500{\mu}g/ml$ of PO and PS for 24 h. After the exposure, cell viability by 3-(4,5-dimethylthiazol-2yl)-2,5-biphenyl tetrazolium bromide (MTT) assay, neutral red uptake (NRU) assay, and cellular morphology by phase contrast inverted microscope were studied. The results showed that PO and PS extracts significantly reduced the cell viability of HepG2 in a concentration dependent manner. The cell viability was recorded to be 67%, 31%, 21%, and 17% at 50, 100, 250, and $500{\mu}g/ml$ of PO, respectively by MTT assay and 91%, 62%, 27%, and 18% at 50, 100, 250, and $500{\mu}g/ml$ of PO, respectively by NRU assay. PS exposed HepG2 cells with $100{\mu}g/ml$ and higher concentrations were also found to be cytotoxic. The decrease in the cell viability at 100, 250, and $500{\mu}g/ml$ of PS was recorded as 70%, 33%, and 15% by MTT assay and 63%, 29%, and 17%, respectively by NRU assay. Results also showed that PO and PS exposed cells reduced the normal morphology and adhesion capacity of HepG2 cells. HepG2 cells exposed with $50{\mu}g/ml$ and higher concentrations of PO and PS lost their typical morphology, become smaller in size, and appeared in rounded bodies. Our results demonstrated preliminary screening of anticancer activity of Portulaca oleracea and Petroselinum sativum extracts against HepG2 cells, which can be further used for the development of a potential therapeutic anticancer agent.

Role of Mesophyll Morphology in Determination of Leaf Photosynthesis in Field Grown Soybeans (포장생육대두의 엽광합성과정에서 엽육세포 형태의 역할)

  • Yun, Jin Il;Lauer, Michael J.;Taylo, S.Elwynn
    • KOREAN JOURNAL OF CROP SCIENCE
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    • v.36 no.6
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    • pp.560-567
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    • 1991
  • Photosynthetic variation in field grown soybean [Glycine max (L.) Merr. cv Hodgson78] was studied in relation to leaf anatomical variation. Variations in mesophyll morphology were accentuated by manipulating source and sink size. At R3 stage, two treatments were started: one was thinning and continu-ous debranching(6. 5 plants rather than 26 plants per m of row and remaining plants were debranched weekly), and the other was continuous partial depodding (allowing only one pod to develop at each mainstem node). Gas exchange characteristics, mesophyll cell volume and surface area per unit leaf surface, and microclimatic parameters were measured on the intact terminal leaflet at the 10th node. Observations were made 5 times with 3 to 4 day intervals starting R4 stage. Two models were used to compute leaf photosynthetic rates: one considered no effect of mesophyll morphology on photosynthesis, and the other considered potential effects of variations in mesophyll cell volume and surface area on diffusion and biochemical processes. Seventy nine percent of total photosynthetic variations observed in the experiment was explained by the latter, while 69% of the same variations was explained by the former model. By incorporating the mesophyll morphology concept, the predictability was improved by 14.6% in the field condition. Additional Index Words: photosynthesis model, leaf anatomy, Glycine max (L.) Merr., mesophyll surface area, mesophyll cell volume.

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Production and Characterizations of Somatic Hybrids between Brassica campestris L. ssp pekinensis and Brassica of oleracea L. var capitata

  • Lian, Yu-Ji;Lim, Hak-Tae
    • Journal of Plant Biotechnology
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    • v.3 no.1
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    • pp.33-38
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    • 2001
  • Protoplasts isolated from inbred lines of Brassica oleracea L. var capitata (cabbage) and Brassica campestris L. ssp. pekinensis (Chinese cabbage) were fused by PEG-mediated method, and somatic hybrid cells were differentiated into plants. for the identification of somatic hybrid plants, ploidy level, plant morphology, and cytological analysis were performed. All of the regenerated plants derived from fused protoplasts were shown to be 2X-4X, or higher ploidy level, presumably due to somatic hybridization or chromosome doubling. The morphology of leaves, petioles, and flowers showed an intermediate phenotype between Chinese cabbage and cabbage. Chromosome numbers in these somatic hybrids ranged mostly from 33 to 38. According to Genomic in situ hybridization (GISH) pattern, signals from both fusion parents of B.campestris or B.oleracea were detected in different colors when chromosomes of putative somatic hybrids were observed.

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Developmental Morphology of Osmundea crispa (Ceramiales, Rhodophyta) from California

  • Nam Ki Wan;Choi Han Gil
    • Fisheries and Aquatic Sciences
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    • v.2 no.1
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    • pp.25-31
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    • 1999
  • Developmental morphology of the red alga, Osmundea crispa (Hollenberg) Nam from California was studied on the basis of liquid-preserved and herbarium specimens. Vegetative axial segment of the species produces two pericentral cells and one trichoblast. Spermatangial filaments (branches) are derived from apical and epidermal cells in pocket-shaped apical pit with an ostiole-like upper opening. Procarp-bearing segment of female trichoblast produces five pericentral cells, of which the fifth functions as supporting cell of carpogonial branch. Tetrasporangial production occurs in random epidermal cells in apical pit of branchlets, and two presporangial cover cells show parallel arrangement to stichidial axis. As this vegetative and reproductive development is included in the generic delineation of Osmundea Stackhouse, O. crispa among the known Osmundea species is characterized by habit forming compact cushion-like clump with angular to terete thallus. It is also distinguished from O. hybrida (AP. de Candolle) Nam without the compressed thallus by the number of pericentral cells in procarp-bearing segment and shape of spermatangial pit. Taxonomic implication of the shape of spermatangial pit is also included.

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