• Journal of The Korean Society of Grassland and Forage Science
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• v.17 no.3
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• pp.285-292
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• 1997

This study was conducted to obtain the transgenic Brnssica napus plants with tobacco Apase gene using the binary vector system of Agrobacteriurn fumefociens. The results obtained were summarized as follows: A repressible acid phosphatase gene of Saccharon~yces cerevisiae, pho105 was used for screening of tobacco Apase cDNA. In order to identify Apase gene in tobacco genome, Southern blot analysis was pcrformed and the Apase gcnc may be present as a single copy, or at most two or three copies, in tobacco genome. To isolate the tobacco Apase gene, tobacco cDNA library was constructed using purifed mRNA from -Pi treated tobacco root and the plaque forming unit of the library was 2.8 x $10^5$ pfu/m${\ell}$, therefore the library might cover all expressed mRNAs. Using pho5 as a probe. tobacco Apase cDNA was cloned, and restriction mapping and Southern blot analysis of cDNA insert were revealed that the 3.6 kb cDNA contained tobacco acid phosphatase cDNA. Plasmid pGA695 -tcAPl was constructed by subcloning tobacco Apase cDNA into the Hind site of pGA695 with 35s promoter which can be expressed constitutively in plants. The Brassica napus cotyledonary petioles were cocultivated with the ,4 grobacteriunz and transferred to the selection medium. The transformed and regenerated plants were transplanted to soil medium. Southern blot analysis was done on the transformed plants, and it was confirmed that a foregin gene was stably integrated into the genonies of B. nnpus plants.

• Journal of Environmental Science International
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• v.24 no.8
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• pp.1037-1043
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• 2015

Since single-use disposable plastic usage has steadily been increasing, recent trends in polymeric research point to increasing demand for eco-friend materials which reduce plastic waste. A huge amount of non-degradable polypropylene (PP)-based pots for seedling culture are discarded for transplantation. The purpose of this study is to investigate an eco-friendly biodegradable material as a possible substitute for PP pot. The blend of poly(lactic acid) (PLA) with poly(butylene adipate-co-terephthalate) (PBAT) was used because of its good mechanical and flexible properties as well as biodegradation. After landfill, various properties of the blend pot were investigated by UTM, SEM, NMR and TGA. The results showed the tensile strength of the blend film rapidly decreased after 5 weeks of landfill due to degradation. From NMR data after landfill, the composition of PLA in the blend was decreased. These results indicate that the biodegradation of the blend preferentially occurs in PLA component. To investigate the effect of holes in pot bottom and side on root growth, a plant in the pot was grown. Some roots came out through holes as landfill period increases. These results indicate that the eco-friendly pot can be directly planted without the removal of pot.

• Restorative Dentistry and Endodontics
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• v.45 no.2
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• pp.22.1-22.10
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• 2020

Objectives: This study investigated the influence of glide path size and operating kinetics on the time to reach the working length and the fracture resistance of Twisted File (TF) and Endostar E3 files. Materials and Methods: A total of 120 mandibular single-rooted premolars were selected. Two methods of kinetic motion (TF adaptive and continuous rotary motion) and file systems (TF and Endostar E3) were employed. The files were used in root canals prepared to apical glide path sizes of 15, 20, and 25. The time taken to reach the working length and the number of canals used before the instrument deformed or fractured were noted. Fractured instruments were examined with scanning electron microscopy. Results: The TF system took significantly more time to reach the working length than the Endostar E3 system. Both systems required significantly more time to reach the working length at the size 15 glide path than at sizes 20 and 25. A greater number of TFs than Endostar E3 files exhibited deformation, and a higher incidence of instrument deformation was observed in adaptive than in continuous rotary motion; more deformation was also observed with the size 15 glide path. One TF was fractured while undergoing adaptive motion. Conclusions: No significant difference was observed between continuous rotary and adaptive motion. The TF system and adaptive motion were associated with a higher incidence of deformation and fracture. Apical glide path sizes of 20 and 25 required significantly less time to reach the working length than size 15.

• Applied Microscopy
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• v.26 no.1
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• pp.79-93
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• 1996

The differentiation of nail matrix and fine structure of matrix cells were studied with light and electron microscope using specimens from nails of thumb finger in Korean fetuses 14 to 24 weeks old. Fetal nail matrix consisted of two horizontal layers, thicker ventral and thinner dorsal matrices, originating from invagination of epidermis in proximal nail field. Matrix being generally thicker in its distal region than the apex became gradually thickened with increase of the fetal age. Each matrix consisted of single layer of basal cells and multiple layers of squamous cells which are arranged close to and parallel to the central axis of the nail mairix. The process of keratinization of fetal nail matrix was noted to be occured concurrently in the ventral and dorsal matrices along the central axis of matrix toward distal and dorsal direction. Squamous cells became matured with accumulation of tonofilaments, increase of keratohyalin granules, discharge of membrane coating granules, and narrowing of intercellular spaces, thickening of plasma membrane and finally being transformed into horny cells of nail plate. Horny cells of nail plate filled with fibrous elements in the electron dense amorphous substance. These findings of keratinization process of fetal nail matrix appeared to be similar to those of keratinization in epidermis and inner root sheath of the hair. In the nail matrix, however, corresponding region to the keratogenous zone of growing hair follicle was not observed. Vacuolated squamous cells of nail matrix seen on light microscopy was considered to be artefactual product, but squamous cells with condensed small nuclei rarely found adjacent nail plate was considered to be one of the squamous cells with unknown function. Proximal end of nail plate was observed on dorsal surface of nail field distal to the proximal nail fold at 14 and 16 weeks old human embryos. Proximal prolongation of the proximal end of nail plate was occured with advancing fetal age and afterward 21 weeks nail plate invaded into nail matrix. Melanin granule containing cells and Merkel cells were present only on the basal layer of dorsal nail matirx.

• Journal of Soil and Groundwater Environment
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• v.22 no.6
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• pp.12-21
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• 2017

A pot experiment was conducted to investigate the transfer of As and cationic heavy metals (Fe, Mn, Zn, Cd and Pb) from soil to rice plant in soil condition with submerged and drained. During the ninety-day monitoring period for soil solution, solubility of reducible elements such as As, Fe and Mn in submerged condition were higher than that of Zn. On the contrary, concentration of Zn in drained condition was higher than that of reducible elements. The concentration of As, Cd, Pb and Zn in rice plant (root, stem, leaf and grain) showed similar pattern with soil solution. The As concentration in each part of rice plant, which cultivated in drained condition, measured 56%~94% lower than those in submerged condition. However, the contents of cationic heavy metals (Cd, Pb and Zn) were represented the opposite result with As. These results are due to mobility of As and cationic heavy metals under different soil drainage conditions which represent oxidation and reduction. Thus soil drainage control can be used as acceptable passive treatment methods to reduce transfer of inorganic contaminants from soil to rice plant. However more detailed examination on soil condition conversion is needed, because yield of rice was decreased when it cultivated in drained condition only. It also needed when soil is contaminated by As and cationic heavy metal because single drainage condition cannot reduce transfer of both kinds of contaminants all.

• The Plant Pathology Journal
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• v.21 no.4
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• pp.317-321
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• 2005

Since 2000 severe rots on aerial and underground parts of paprika (Capsicum annum L.) has occurred in most surveyed glasshouses throughout the country. A total of 56 isolates of a fungus were consistently isolated from various plant parts such as fruit, stem, branch, and root collected from 16 farms in five provinces. Anamorph stage of the fungus was identified as Fusarium solani based on its morphological characteristics. However, the fungus readily produced a sexual structure of perithecia on infected plant tissues and on agar media. Since the fungus formed abundant perithecium by a single isolate, it was considered as a homothallic strain of Nectria haematococca, the teleomorph of F. solani. Irregularly globose perithecia with orange to red color formed sparsely to gregariously on dead tissues of fruits and basal stems at the late infection stage, which is a diagnostic sign for the disease. Perithecia ranged from 125 to 220 ${\mu}m$ in diameter varied among isolates. Asci enveloping eight ascospores were cylindrical and measured 60-80x8-12 ${\mu}m$. Ellipsoid to obovate ascospores are two-celled and measured 11-18x4-7 ${\mu}m$. Ascospores were hyaline, slightly constricted at the central septum, and revealed longitudinal striations that is characteristic of the species. This fungus that has never been reported in Korea has previously become a threat to paprika cultivation because of its strong pathogenicity and nationwide distribution.

• The Plant Pathology Journal
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• v.36 no.6
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• pp.591-599
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• 2020

Phytophthora root and stem rot reduce soybean yields worldwide. The use of R-gene type resistance is currently crucial for protecting soybean production. The present study aimed to identify the genomic location of a gene conferring resistance to Phytophthora sojae isolate 2457 in the recombinant inbred line population developed by a cross of Daepung × Daewon. Singlemarker analysis identified 20 single nucleotide polymorphisms associated with resistance to the P. sojae isolate 2457, which explained ~67% of phenotypic variance. Daewon contributed a resistance allele for the locus. This region is a well-known location for Rps1 and Rps7. The present study is the first, however, to identify an Rps gene locus from a major soybean variety cultivated in South Korea. Linkage analysis also identified a 573 kb region on chromosome 3 with high significance (logarithm of odds = 13.7). This genomic region was not further narrowed down due to lack of recombinants within the interval. Based on the latest soybean genome, ten leucine-rich repeat coding genes and four serine/ threonine protein kinase-coding genes are annotated in this region, which all are well-known types of genes for conferring disease resistance in crops. These genes would be candidates for molecular characterization of the resistance in further studies. The identified R-gene locus would be useful in developing P. sojae resistant varieties in the future. The results of the present study provide foundational knowledge for researchers who are interested in soybean-P. sojae interaction.

• FLOWER RESEARCH JOURNAL
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• v.16 no.1
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• pp.71-75
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• 2008

The object of this study was to determine the optimum concentrations of boron and IBA and dipping time, and to investigate the effect of combined-treatment of boron and IBA for the improvement of rooting of semi-hardwood cutting of Styrax japonica. The rooting percentage and the number of roots of cuttings increased with short dipping treatment of $7,000mg{\cdot}L^{-1}$ IBA and combined treatment of $100mg{\cdot}L^{-1}$ IBA and $20mg{\cdot}L^{-1}$ boron or $100mg{\cdot}L^{-1}$ IBA and $60mg{\cdot}L^{-1}$ boron. The rooting percentage, no. of roots and fresh weight were higher in combined treatment of boron and IBA than treatment of IBA alone. Either $100mg{\cdot}L^{-1}$ or $200mg{\cdot}L^{-1}$ was regarded as in appropriate level of IBA and the optimal dipping time was three hour in single treatment of IBA. It is concluded that the combined treatment of low concentrations of IBA and boron could be substituted for the treatment of high concentration IBA.

• Journal of the Korean Society of Propulsion Engineers
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• v.17 no.2
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• pp.122-127
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• 2013

The paper includes the analytic results of pressure fluctuation data from the combustion of an oxidizer-rich preburner applicable to high-performance, closed-cycle liquid rocket engine systems. The combustion experiments went through two different steps of a chamber pressure during single run. Self-excited pressure fluctuations with a frequency of 78 Hz were observed only at the relatively low chamber pressure condition. These pressure fluctuations are regarded as a bulk mode. The intensity of pressure fluctuations by a root-mean-square value is 13.3% normalized by the chamber static pressure and no pressure excitation was observed at the design pressure condition. The bulk mode has an identical phase across the inside of the chamber and reveals the similar characteristics to the Helmholtz resonator.

• Proceedings of the Ginseng society Conference
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• 2002.10a
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• pp.467-476
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• 2002

A large number of individual ginseng plants have been selected in the farmer's fields to develop new ginseng varieties with desirable traits since 1970s. Among them, Hwangsukjong with green stem and yellow berry was selected as a ginseng germplasm. The phenotype of Hwangsukjong is quite different from Jakyungjong that has violet stem and red berry and has been cultivated in most of ginseng fields. Therefore, Hwangsukjong was crossed with Jakyungjong to clarify the inheritance of stem color and then the characteristics of $F_1\;and\;F_2$ hybrids were investigated. $F_1$ hybrid plants were similar to Jakyungjong in most of aerial part characters and showed hybrid vigor in fresh weight of root and weight of 100 seeds. In $F_2$ generation, the stem color was segregated in a ratio of 3 violet to 1 green. From this result, it was elucidated that violet color was controlled by single dominant gene. In another experiment, DNA was extracted from parents (Jakyungjong and Hwangsukjong) and $F_1$ hybrid. For each primer evaluated, multiple band profile was produced comprising from one to five major bands plus a varying number of minor bands and amplified bands were detected among most primers. In case of UBC primer number 13, 17, 30, 31, and 43, band patterns of parents and $F_1$ hybrid were very similar, but the others were not. Especially, in {\sharp}1$, {\sharp}4$, and {\sharp}33$, specific band was produced in Hwangsukjong and $F_1$ hybrid while in {\sharp}6$, another specific band was produced in Jakyungjong and $F_1$ hybrid. Therefore, $F_1$ hybrid had all specific bands at these primers. So, these selective markers could be used for identification of characteristics of $F_2$ hybrids