• Journal of Embryo Transfer
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• v.27 no.3
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• pp.189-192
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• 2012

Although embryonic stem cells (ESCs) or ES-like cells are reported from many mammalian species other than the mouse, the culture system for murine ESCs may not be suitable to the other species. Previously many other research groups have modified either human or mouse ESC culture systems for bovine ESC culture. In this study, we compared three different culture mediums consisting of DMEM, ${\alpha}$-MEM or KnockOut$^{TM}$-DMEM (KO), which are modified from human or mouse ESC culture system, for the generation of bovine ESCs. In this study, some pre-requisite events which are important for establishment and long-term propagation of ESCs such as inner cell mass (ICM) attachment on feeder cells, primary colony formation and sustainability after passaging. Once the ICM clumps attached on feeder cells, this was designated as passage 0. In regards to the rate of ICM attachment, ${\alpha}$-MEM was superior to the other systems. For primary colony formation, there was no difference between DMEM and ${\alpha}$-MEM whereas KO showed lower formation rate than the other groups. For passaging, the colonies were split into 2~4 pieces and passed every 5~6 days. From passage 1 to passage 3, DMEM system seemed to be appropriate for maintaining putative bovine ESCs. On the other hand, ${\alpha}$-MEM tended to be more suitable after passage 6. Although ${\alpha}$-MEM support to maintain a ES-like cell progenies to passage 15, all three culture systems which are modified from human or mouse ESC culture media failed to retain the propagation and long-term culture of putative bovine ESCs. Our findings imply that more optimized alternative culture system is required for establishing bovine ESC lines.

• International Journal of Oral Biology
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• v.42 no.4
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• pp.203-211
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• 2017

The aim of this study was to evaluate the role of demineralized and particulate autogenous tooth, and interleukin-6 in bone regeneration. A demineralized and particulate autogenous tooth was prepared and human osteoblast-like cells (MG63) and human osteosarcoma cells were inoculated into the culture. The rate of cell adhesion, proliferation and mineralization were examined, and the appearance of cellular attachment was observed. An 8 mm critical size defect was created in the cranium of rabbits. Nine rabbits were divided into three groups including: An experimental group A (3 rabbits), in which a demineralised and particulate autogenous tooth was grafted; an experimental group B (3 rabbits), in which a demineralized, particulate autogenous tooth was grafted in addition to interleukin-6 (20 ng/mL); and a control group. The rabbits were sacrificed at 1, 2, 4 and 6 weeks for histopathological examination with H-E and Masson's Trichrome, and immunohistochemistry with osteocalcin. The cell-based assay showed a higher rate of cell adhesion, mineralization and cellular attachment in the experimental group A compared with the control group. The animal study revealed an increased number of osteoclasts, newly formed and mature bones in the experimental group A compared with the control group. Eventually, a higher number of osteoclasts were observed in the experimental group B. However, the emergence of newly formed and mature bone was lower than in the experimental group A. The current results suggest that treatment with demineralized and particulate autogenous tooth and interleukin-6 is not effective in stimulating bone regeneration during the bone grafting procedure.

• Journal of Periodontal and Implant Science
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• v.49 no.2
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• pp.90-104
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• 2019

Purpose: The aim of this study was to evaluate clinical and radiographic changes and the survival rate after periodontal surgery using deproteinized bovine bone mineral (DBBM) with 10% collagen or DBBM with a collagen membrane in endo-periodontal lesions. Methods: A total of 52 cases (41 patients) with at least 5 years of follow-up were included in this study. After scaling and root planing with or without endodontic treatment, periodontal regenerative procedures with DBBM with 10% collagen alone or DBBM with a collagen membrane were performed, yielding the DBBM + 10% collagen and DBBM + collagen membrane groups, respectively. Changes in clinical parameters including the plaque index, bleeding on probing, probing pocket depth, gingival recession, relative clinical attachment level, mobility, and radiographic bone gains were evaluated immediately before periodontal surgical procedures and at a 12-month follow-up. Results: At the 12-month follow-up after regenerative procedures, improvements in clinical parameters and radiographic bone gains were observed in both treatment groups. The DBBM + 10% collagen group showed greater probing pocket depth reduction ($4.52{\pm}1.06mm$) than the DBBM + collagen membrane group ($4.04{\pm}0.82mm$). However, there were no significant differences between the groups. Additionally, the radiographic bone gain in the DBBM + 10% collagen group ($5.15{\pm}1.54mm$) was comparable to that of the DBBM + collagen membrane group ($5.35{\pm}1.84mm$). The 5-year survival rate of the teeth with endo-periodontal lesions after periodontal regenerative procedures was 92.31%. Conclusions: This study showed that regenerative procedures using DBBM with 10% collagen alone improved the clinical attachment level and radiographic bone level in endo-periodontal lesions. Successful maintenance of the results after regenerative procedures in endo-periodontal lesions can be obtained by repeated oral hygiene education within strict supportive periodontal treatment.

• Journal of Korean Society of Water and Wastewater
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• v.23 no.6
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• pp.703-709
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• 2009

In this study, an artificial-waterway experiment was conducted, using an attachment plate, on which algae from Nanakita river was placed, to examine the influence exerted by the variation of the dissolved-silicon concentration on the river periphyton. As a result, the variation of the dissolved-silicon concentration was found to exert an influence on the density of the adhesion diatom, and the mole ratio limits of the silica were about $Si/P{\fallingdotseq}182$ and $Si/N{\fallingdotseq}16.4$ or less. Moreover, the mole ratio that is necessary for proliferation was found to be larger than the value of the oceanic algae. Senedesmus sp. and Ankistrodesmus sp., which used silica in adhesion chlorophyta, received the influence of the silicon concentration strongly, and the twowere found to be superior in the environment, making silica a restriction factor.

• Journal of Environmental Health Sciences
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• v.21 no.2
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• pp.20-26
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• 1995

The objective of this study is to estimate the effect of the bed expansion and the characteristics of attached biomass in the start-up in the anaerobic fluidized bed reactor(AFBR). The fluidized bed reactor was operated with bacteria supported on the bed of granular activated carbon(GAC). The reactor was operated at 35$\circ$C, 5 kg $COD/m^3\cdot day$ at bed expansion varying from 0 to 100% with soluble glucose wastewater(5,000 mg/l). When the effluent reached a steady state at 100% of bed expansion, maximum COD removal efficiency of 87.3% and 0.031 $m^3CH_4/kg COD_{removed}$ were obtained. At higher bed expansion, COD removal efficiency, methane production rate and biogas production rate increased. Especially, at 50% of bed expansion, the efficiency of the treatment increasedg rapidly in the AFBR. The biomass colonized in the pits and crevices of the GAC particle and no complete biofilm was established in the bioreactor during the experiment.

• Journal of Environmental Health Sciences
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• v.27 no.3
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• pp.27-34
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• 2001

This paper discussed the shape effect of ceramic support carrier in order to facilitate biomass immobilization. The shape of ceramic support carrier was modified hollow pipe type into hollow gear type. After seeding, microorganisms were attached in crevices where protection from shear forces or surfaces where easy to contact with support carrier surface. In case of hollow gear type carrier, initial attachment rate was faster than that of hollow pipe type and obtained thick biofilm. Synthetic wastewater(COD:75~880 mg/L, organic loading rate:0.36~4.22 kgCOD/㎥.d) was treated aerobic fixed bed biofilm reactor where 100% of the volume was filled with the ceramic carrier. COD removal efficiency of reactor filled with gear type support carrier was a little high withing 70 days, and then showed similar removal efficiency. It was found that highly loaded operation with up to 4.22 kgCOD/㎥.d was possible in both reactor. Total biomass amounts of pipe type was higher than gear type, however, attached biomass of gear type was higher than that of pipe type.

• Korean Journal of Culture and Social Issue
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• v.26 no.4
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• pp.479-499
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• 2020

The present study explored psychological factors related to the desire to have children of young adults who had yet to marry and begin a family. To do so, the present study investigated the relationships among the desire to have children, adult attachment styles and belief in a just world (DJ-self, PJ-self, DJ-others, and PJ-others). This study analyzed the self-reported data of 260 adults aged 20 to 39. Hierarchical regression analysis revealed that after controlling for gender, individuals with more avoidant models of close adult relationships showed less desire to have children. Moreover, the belief in a just world accounted for an additional variance. Specifically, participants' PJ-others positively predicted their desire to have children. These results suggest that individuals' expectations about close relationships and justice of their society might explain a part of their desire to have children. The implications, limitations, and future directions of the study were discussed.

• Tunnel and Underground Space
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• v.32 no.6
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• pp.373-385
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• 2022

The drum cutter, which is used in the form of an attachment of a excavator, is very useful in that it can be used in connection with a excavator that can perform various tasks in the field. This study estimated the load and torque acting on the drum cutter attachment by measuring the hydraulic pressure and strain that appear during excavation on the exposed rock slope using the drum cutter installed in the excavator. Working conditions such as the operation angle between the boom and arm of the excavator were divided into eight working modes. And as a result of analyzing the variations in hydraulic pressure and action force according to the working mode, it was confirmed that the hydraulic pressure and flow rate can be driven without any problems within the range considered in the manufacturing specifications of the drum cutter. The average load and torque acting on the drum cutter were within the range of the manufacturing specifications, but the maximum load was up to four times the specification. Because sumping was not properly performed due to the high ground strength and the ground included discontinuous surfaces in some locations, no trend of load and torque was found depending on the angle between the boom and arm of the excavator. However, it is believed that this result can be used to determine the range of loads and torques that appear on the drum cutter when excavating a high-intensity rock.

• Korean journal of applied entomology
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• v.44 no.2
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• pp.145-150
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• 2005

Three Korean isolates of entomopathogenic nematodes, Steinernema carpocapsae KCTC 0981BP (ScK), S. glaseri Dongrae (SgD), and Heterorhabditis sp. KCTC 0991BP (HsK), were evaluated for the control of a turfgrass pest, Popillia quadriguttata. Three days after treatment, all nematodes showed high pathogenicity to adult P. quadriguttata with $97.5\%$ mortality by ScK, $90.8\%$ by HsK, and $80\%$ by SgD at the concentration of 900 infective juveniles per adult. Nematode attachment and infection rate to adult P. quadriguttata were various depending on nematode species and inoculation density. The rate of nematode attachment was $90.8\%$ in HsK, $90.6\%$ in SgD, and $35\%$ in ScK, resfectively at the concentration of 900 infective juveniles per adult. The infection rate that represents the rate of detected nematode from inside insect of body was $97.5\%$ in ScK, $ 80\%$ in both HsK and SgD at the 900 concentration of infected juveniles. The infection rate, however, was decreased to $27.5\%$ in ScK, $72.5\%$ in SgD, but no nematodes was detected in HsK at the concentration of 90 infective juveniles.

• International Journal of Fluid Machinery and Systems
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• v.3 no.2
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• pp.129-136
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• 2010

The attachment of inducer upstream of main impeller is an effective method to improve the suction performance of turbopump. However, various types of cavitation instabilities are known to occur even at the designed flow rate as well as in the partial flow rate region. The cavitation surge occurring at partial flow rates is known to be strongly associated with the inlet back flow. In the present study, in order to understand the detailed structure of internal flow of inducer, we firstly carried out the experimental and numerical studies of non-cavitating flow, focusing on the flow field near the inlet throat section and inside the blade passage of a two bladed inducer at a partial flow rate. The steady flow simulation with cavitation model was also made to investigate the difference of flow field between in the cavitating and no-cavitating conditions.