• Journal of Plant Biology
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• v.29 no.2
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• pp.129-133
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• 1986

Transections of the stem region close to the shoot apex show the occurrence of an outer, complete ring of procambium and an inner group of discrete procambial strands. From the outer ring, small, discrete vascular bundles and vascular cambium originate, while the inner group forms the discrete, medullary vascular bundles with intrafascicular cambium. Secondary thickening is essentially due to the activity of the cylinder or complete ring of vascular cambium that originates from the procambium. The medullary intrafascicular cambia also form some secondary tissues. The vascular cambium produces secondary xylem inwards and secondary phloem outwards as in the normal secondary thickening process. The distinctive feature, however, is perpetual discreteness of the medullary vascular bundles. No successive series of cambia or secondary vascular bundles are found.

• Applied Microscopy
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• v.50
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• pp.27.1-27.6
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• 2020

Transition metal dichalcogenides (TMD), which is composed of a transition metal atom and chalcogen ion atoms, usually form vacancies based on the knock-on threshold of each atom. In particular, when electron beam is irradiated on a monolayer TMD such as MoS₂ and WS₂, S vacancies are formed preferentially, and they are aligned linearly to constitute line defects. And then, a hole is formed at the point where the successively formed line defects collide, and metal clusters are also formed at the edge of the hole. This study reports a process in which the line defects formed in a monolayer WS₂ sheet expends into holes. Here, the process in which the W cluster, which always occurs at the edge of the formed hole, goes through a uniform intermediate phase is explained based on the line defects and the formation behavior of the hole. Further investigation confirms the atomic structure of the intermediate phase using annular dark field scanning transition electron microscopy (ADF-STEM) and image simulation.

• Journal of Ocean Engineering and Technology
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• v.18 no.5
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• pp.57-63
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• 2004

Various propulsion systems, applicable for a G/T 47,000 class mid-size cruise ship, are discussed and a comparative study on stern forms and hull resistance characteristics is carried out, in relation to these propulsion systems. Based on shipyard production logs on similar cruise ships, a reference hull form of a single shaft propulsion system with center-skeg, is generated. Then two new stern hull forms are derived by using a hull transform technique: consisting of one stern form using a twin-skeg system and the other using the Azipod system. Using a CFD-based commercial flaw analysis program, WAVIS (WAve and VIScous flaw analysis system for hull form development), various hydrodynamic characteristics, including wave profiles and ship hull resistance, are compared for three hull forms.

• Current Research on Agriculture and Life Sciences
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• v.11
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• pp.111-120
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• 1993

We investigated in the existential forms of heavy metals and their distribution in plant and soil surrounding ruined mine in Daduk area. The content of heavy metals in soils was more plentiful in A soil than that in another soil, excepting only Mn. The content of Mn in soils was greater in B soil than those in another soils. The content of each heavy metals, according to existential form, had different patterns on the comparision of each elements ; organic-form on Cd and As, Carbonate-form Cu, Pb and Mn and Residual-form on Fe and Zn. The popularity ration of M. senensis and J. decipiens were about 65% and 72%, respectively, and which means that these plants had resistances to heavy metals. The contents of heavy metals absorbed in root was higher than those of stem except Mn, In M. sinensis, the contents of Zn in root was similar to that of stem. To study the heavy metal contents in water, the highest content of heavy metal, mainly Fe, Mn and Zn, were calculated in extracting water.

• Clinical and Experimental Reproductive Medicine
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• v.35 no.1
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• pp.39-48
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• 2008

Objective: The aim of this study was to investigate whether multipotent germline stem cells (MGSCs) can be established from neonatal mouse testis. Methods: Various cells containing MGSCs were collected from neonatal testis of ICR mice and allocated to plates for in vitro culture. After 7 days in culture, the cells were passed to a fresh culture plate and continuously cultured. From the third or fourth passage, the presumed MGSCs were cultured and maintained on mitomycin C-inactivated STO feeder cells. The MGSCs were cultured in a condition where mouse embryonic stem cells (ESCs) are cultured. Characteristics of the MGSCs were evaluated by RT-PCR, immunocytochemistry, alkaline phosphatase activity, karyotyping, and transmission electron microscopy. Results: Two MGSCs lines were established from 9 pooled sets of neonatal testicular cells. MGSCs colonies were morphologically undistinguishable from ESCs colonies and both MGSC lines as well as ESCs expressed undifferentiated stem cell markers, such as Thy-1, Oct-4, Nanog, Sox2 and alkaline phosphatase. Fine structure of undifferentiated MGSCs were similar to those of ESCs and 60% of MGSCs (12/20) had normal karyotype at passage 10. They were able to form embryoid bodies (EBs) and MGSC-derived EBs expressed marker genes of three germ layers. Conclusion: We could establish the MGSCs from neonatal mouse testis and they were differentiated to multipotent lineages of three germ layers. Molecular characteristics of MGSCs were similar to those of ESCs. Our results suggest a possibility that multipotent stem cells derived from testis, the MGSCs, could replace the ESCs in biotechnology and regenerative medicine.

• Journal of Korean Society of Forest Science
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• v.90 no.3
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• pp.331-337
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• 2001

This study was performed to develope stem analysis program(Stemwin1.0) which can be used in PC with MS-Windows operating system. Stemwin1.0 uses width of annual tree ring measured with 1/100mm unit, and calculate increments of several growth factors such as DBH, height and volume with various methods. Mean DBH can be calculated by arithmetic and quadratic mean methods. Height can be estimated by parallel line, line extending and height curve methods. Volume can be estimated by Huber, Smalian, and Spline functions. Not only Total growth, Mean Annual Increment(MAI) and Current Annual Increment(CAI) of growth factors, but also merchantable volume and height, form factor, growth rate, and merchantable volume rate are automatically calculated. Stemwin1.0 can also output accurate stem taper curve with various scale, and prepare stem taper data(diameter at different disk heights) for statistical analysis for deriving stem taper model. Stemwin1.0 can export output data and graph to Excel for more compatible use of it.

• Microbiology and Biotechnology Letters
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• v.41 no.3
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• pp.320-326
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• 2013

In a previous study, we investigated the antioxidative and cellular protective effects of Parthenocissus tricuspidata stem extracts. In this study, we prepared nano-emulsion containing P. tricuspidata stem extract to improve skin permeation. The particle size of the nano-emulsion using the microfluidizer was 302 nm. Its loading efficiency was over 86%. The size distribution of the nano-emulsion took a monodispersed form and the nano-emulsion was more stable than typical emulsion without using microfluidizer during a 2 week period. In vitro skin permeation study of nano-emulsion containing P. tricuspidata stem extracts was carried out using Franz diffusion cell. The 1,3-butylene glycol used as a control group had 32.59% skin permeation efficiency. The skin permeation efficiency of the nano-emulsion was 42.47%. Also, we observed the antibacterial activity of the ethyl acetate fraction on skin flora for prospective applications as a natural antimicrobial. The ethyl acetate fraction had antibacterial activities higher than methyl paraben on Staphylococcus aureus, and Bacillus subtilis. These results indicate that nano-emulsion containing P. tricuspidata stem extracts could possess valued applications in cosmetic formulations for improving skin permeation. Also, based on the antibacterial activities on skin flora, antioxidative and cellular protective effects shown in our previous study, we suggest that P. tricuspidata stem extracts could be used as functional cosmetic materials.

• International Journal of Oral Biology
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• v.38 no.4
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• pp.161-167
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• 2013

Human dental pulp stem cells (DPSCs) are multi-potent mesenchymal stem cells that have several differentiation potentials. An understanding of thetissues that differentiate from these cells can provide insights for future regenerative therapeutics and tissue engineering strategies. The mesiodens is the most frequent form of supernumerary tooth from which DPSCs can differentiate into several lineages similar to cells from normal deciduous teeth. Recently, it has been shown that nanoscale structures can affect stem cell differentiation. In our presentstudy, we investigated the effects of a 250-nm nanoscale ridge/groove pattern array on the osteogenic and adipogenic differentiation of dental pulp cells from mesiodenscontaining human DPSCs. To this end, the expression of lineage specific markers after differentiation induction was analyzed by lineage specific staining and RT-PCR. The nanoscale pattern arrayed surface showed apositive effect on the adipogenic differentiation of DPSCs. There was no difference between nanoscale pattern arrayed surface and conventional surface groups onosteogenic differentiation. In conclusion, the nanoscale ridge/groove pattern arrayed surface can be used to enhance the adipogenic differentiation of DPSCs derived from mesiodens. This finding provides an improved understanding of the effects of topography on cell differentiation as well as the potential use of supernumerary tooth in regenerative dental medicine.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.43 no.4
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• pp.40-48
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• 2011

In this study, we investigated the usability of new powdered additives in the paperboard industry. We manufactured the powdered additives from peanut husks and garlic stems by grinding. The chemical composition, particle size, particle size distribution, and particle shape were investigated to identify the basic properties of the powdered raw materials. To determine the effect of the powdered additives on paper properties, handsheets were prepared by adding the powdered additives to the pulp slurry. The chemical composition, such as the contents of holocellulose, lignin, and ash, showed similar values to those of other biomass materials. The particles of peanut husk powder were irregularly shaped, smaller, and had a broader particle size distribution than those of the garlic stem powder, which had the fibril form. The particles of the two powdered raw materials showed a positioning of expansion in the fiber network, resulting in increased bulk and a loss of strength. Handsheets containing garlic stem particles were stronger than handsheets containing peanut husk particles. Finally, the new powdered additives are beneficial to the bulk of paperboard.

• BMB Reports
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• v.53 no.8
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• pp.425-430
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• 2020

Tumor necrosis factor-inducible gene 6 protein (TSG-6) is a cytokine secreted by mesenchymal stem cells (MSCs) and regulates MSC stemness. We previously reported that TSG-6 changes primary human hepatic stellate cells (pHSCs) into stem-like cells by activating yes-associated protein-1 (YAP-1). However, the molecular mechanism behind the reprogramming action of TSG-6 in pHSCs remains unknown. Cluster of differentiation 44 (CD44) is a transmembrane protein that has multiple functions depending on the ligand it is binding, and it is involved in various signaling pathways, including the Wnt/β-catenin pathway. Given that β-catenin influences stemness and acts downstream of CD44, we hypothesized that TSG-6 interacts with the CD44 receptor and stimulates β-catenin to activate YAP-1 during TSG-6-mediated transdifferentiation of HSCs. Immunoprecipitation assays showed the interaction of TSG-6 with CD44, and immunofluorescence staining analyses revealed the colocalization of TSG-6 and CD44 at the plasma membrane of TSG-6-treated pHSCs. In addition, TSG-6 treatment upregulated the inactive form of phosphorylated glycogen synthase kinase (GSK)-3β, which is a negative regulator of β-catenin, and promoted nuclear accumulation of active/nonphosphorylated β-catenin, eventually leading to the activation of YAP-1. However, CD44 suppression in pHSCs following CD44 siRNA treatment blocked the activation of β-catenin and YAP-1, which inhibited the transition of TSG-6-treated HSCs into stem-like cells. Therefore, these findings demonstrate that TSG-6 interacts with CD44 and activates β-catenin and YAP-1 during the conversion of TSG-6-treated pHSCs into stem-like cells, suggesting that this novel pathway is an effective therapeutic target for controlling liver disease.