• BMB Reports
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• v.56 no.7
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• pp.392-397
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• 2023

In this study, recombinant Fc-fused Prostate acid phosphatase (PAP) proteins were produced in transgenic plants. PAP was fused to immunoglobulin (Ig) A and M Fc domain (PAP-IgA Fc and PAP-IgM Fc), which were tagged to the ER retention sequence KDEL to generate PAP-IgA FcK and PAP-IgM FcK. Agrobacterium-mediated transformation was performed to produce transgenic tobacco plants expressing four recombinant proteins. Genomic PCR and RT-PCR analyses confirmed the transgene insertion and mRNA transcription of PAP-IgA Fc, PAP-IgM Fc, PAP-IgA FcK, and PAP-IgM FcK in tobacco plant leaves. Western blot confirmed the expression of PAP-IgA Fc, PAP-IgM Fc, PAP-IgA FcK, and PAP-IgM FcK proteins. SEC-HPLC and Bio-TEM analyses were performed to confirm the size and shape of the plant-derived recombinant PAP-Fc fusion proteins. In mice experiments, the plant-derived IgA and IgM Fc fused proteins induced production of total IgGs including IgG1 against PAP. This result suggests that IgA and IgM Fc fusion can be applied to produce recombinant PAP proteins as a prostate cancer vaccine in plant expression system.

• Microbiology and Biotechnology Letters
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• v.34 no.4
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• pp.342-351
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• 2006

The aim of this study was to survey susceptibilities of Escherichia coli and Klebsiella pneumoniae isolates against cefotaxime and to determine the prevalences of CTX-M type extended-spectrum $\beta$-lactamases (ESBLs) producing E. coli and K. pneumoniae in Korea. During the period of February to July, 2005, 153 E. coli and 52 K. neumoniae isolates were collected from 2 hospitals in Busan. Antimicrobial susceptibilities to cefotaxime were tested by the disk diffusion method. ESBL production of E. coli and K. pneumoniae was determined by the double disk synergy test. MICs of $\beta$-lactam antibiotics were determined by the agar dilution method. Blac$_{CTX-M}$ genes of the organism were detected by PCR. Among 153 isolates of E. coli and 52 isolates of K. neumoniae, 27 (17.6%) and 25 (48.0%) were intermediate or resistant to cefotaxime, respectively. Twenty-three (15.0%) isolates out of 153 E. coli and 13 (25.0%) out of 52 K. neumoniae isolates showed positive results for ESBL by the double disk synergy test. Twenty isolates out of 23 ESBL producing E. coli and 12 out of 13 ESBL producing K. neumoniae isolates harbored biacTx-M gene,11 of ESBL producing E. coli and 12 of ESBL producing K. neuinoniae isolates harbored bla$_{CTX-M}$ gene, 11 of the ESBL producing E. coli and 2 of ESBL producing K. neumoniae isolates harbored bla$_{TEM}$ gene, and 1 of the ESBL producing E. coli and 12 of ESBL producing K. neumoniae isolates harbored bla$_{SHV}$ gene. E. coli and K. neumoniae isolates producing CTX-M-type ESBLs were not uncommon in Korea. It is thought that continuous survey are necessary for inspecting the spread and novel variants of CTX-M-type ESBL genes. Further me]'e investigation and research on ESBL producing strains are needed in order to prevent the spread of resistant bacteria.

• Journal of Pharmacopuncture
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• v.19 no.1
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• pp.37-44
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• 2016

Objectives: This study examined the relative efficacies of a derivative of betulinic acid (dBA) and its poly (lactide-co-glycolide) (PLGA) nano-encapsulated form in A549 lung cancer cells in vivo and in co-mutagen [sodium arsenite (SA) + benzo[a]pyrene (BaP)]-induced lung cancer in mice in vivo. Methods: dBA was loaded with PLGA nanoparticles by using the standard solvent displacement method. The sizes and morphologies of nano-dBA (NdBA) were determined by using transmission electron microscopy (TEM), and their intracellular localization was verified by using confocal microscopy. The binding and interaction of NdBA with calf thymus deoxyribonucleic acid (CT-DNA) as a target were analyzed by using conventional circular dichroism (CD) and melting temperature (Tm) profile data. Apoptotic signalling cascades in vitro and in vivo were studied by using an enzyme-linked immunosorbent assay (ELISA); the ability of NdBA to cross the blood-brain barrier (BBB) was also examined. The stage of cell cycle arrest was confirmed by using a fluorescence-activated cell-sorting (FACS) data analysis. Results: The average size of the nanoparticles was ~ 110 nm. Confocal microscopy images confirmed the presence of NdBA in the cellular cytoplasm. The bio-physical properties of dBA and NdBA ascertained from the CD and the Tm profiles revealed that NdBA had greater interaction with the target DNA than dBA did. Both dBA and NdBA arrested cell proliferation at G0/G1, NdBA showing the greater effect. NdBA also induced a greater degree of cytotoxicity in A549 cells, but it had an insignificant cytotoxic effect in normal L6 cells. The results of flow cytometric, cytogenetial and histopathological studies in mice revealed that NdBA caused less nuclear condensation and DNA damage than dBA did. TEM images showed the presence of NdBA in brain samples of NdBA fed mice, indicating its ability to cross the BBB. Conclusion: Thus, compared to dBA, NdBA appears to have greater chemoprotective potential against lung cancer.

• Fire Science and Engineering
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• v.28 no.1
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• pp.44-51
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• 2014

Smoke from fire is a mixture of combustion gases and particles which include micro-droplets formed from condensed organic vapors and carbonaceous agglomerates. The inhalation of smoke particles causes adverse health effects, and it is prerequisite for the hazard and risk analysis of the smoke particles to know how they behaviour in the respiratory tract. The characteristics of the absorption and adsorption of toxic gases and the amount and location of the particle deposition within the respiratory tract that determine the adverse health effects are related to the morphology and the size distribution of smoke particles. In the present work, as a preliminary study for the adverse health effects of smoke particles, the morphologies of the smoke particles from combustible materials were investigated for each fire stage: smouldering, well-ventilated flaming, small under-ventilated flaming, fully-developed under-ventilated fire. The steady-state tube furnace method given in ISO/TS 19700 was used for the generation of smoke particles. The fire stages were controlled by changing furnace temperature and equivalent ratio. The morphologies were analyzed by using Transmission Electron Microscope (Bio-TEM) by collecting the particles on TEM grids put on each stage of a cascade impactor.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.22 no.3
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• pp.13-19
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• 2021

This study examined the effects of stacking faults on the thermoelectric properties for n-type SiC semiconductors. Porous SiC semiconductors with 30~42 % porosity were fabricated by the heat treatment of pressed ��-SiC powder compacts at 1600~2100 ℃ for 20~120 min in an N2 atmosphere. XRD was performed to examine the stacking faults, lattice strain, and precise lattice parameters of the specimens. The porosity and surface area were analyzed, and SEM, TEM, and HRTEM were carried out to examine the microstructure. The electrical conductivity and the Seebeck coefficient were measured at 550~900 ℃ in an Ar atmosphere. The electrical conductivity increased with increasing heat treatment temperature and time, which might be due to an increase in carrier concentration and improvement in grain-to-grain connectivity. The Seebeck coefficients were negative due to nitrogen behaving as a donor, and their absolute values also increased with increasing heat treatment temperature and time. This might be due to a decrease in stacking fault density, i.e., a decrease in stacking fault density accompanied by grain growth and crystallite growth must have increased the phonon mean free path, enhancing the phonon-drag effect, leading to a larger Seebeck coefficient.

• Journal of Veterinary Clinics
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• v.28 no.6
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• pp.576-580
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• 2011

Silver has potent antibacterial activity against a variety of bacteria while maintaining low toxicity in mammalian cells. This study was conducted to investigate the possible mechanism underlying the bactericidal effects of silver ions against bovine mastitis pathogens using electron microscopy. We used two different bacterial strains, Escherichia coli and Staphylococcus aureus, which are primarily responsible for the majority of bovine mastitis cases. Interaction between the bacteria and silver ions (50 ${\mu}g/mL$, 2 hours) were studied using energy-filtering transmission electron microscopy (EFTEM). EFTEM images showed that E. coli and S. aureus cells treated with the silver ions had distorted plasma membranes, silver ions attached to the outer membranes, scattered electron-light material, and leakage of cell contents from disrupted cell membranes.

• Applied Microscopy
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• v.31 no.4
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• pp.367-374
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• 2001

Leaves of two developmental stages of Salsola species, young and mature, were examined to reveal the structural and functional relationships in the photosynthetic tissue using anatomical and ultrastructural criteria. Both young and mature leaves had Kranz anatomy of the Salsolid type with two layers of chlorenchyma on the leaf periphery: an outer layer of palisade mesophyll cells and an inner layer of compact bundle sheath cells with centripetally arranged organelles. The chlorenchyma was continuous in young leaves , while it was discontinuous in mature leaves. The main vascular bundle occupied the central position in the leaf. but the small peripheral vascular bundles were in contact with the chlorenchyma. Structural dimorphism of chloroplasts was obvious in bundle sheath cells of mature leaves exhibiting noticeable grana reduction, whereas mesophyll cell chloroplasts had well developed grana in all cases. Plasmodesmata were less numerous and rather simple in young leaves relative to well-developed secondary plasmodesmata of the later stage. According to the current data, features of two stages of Salsola leaves corresponded to NADP-ME bio-chemical subtype on the basis of photosynthetic cell ultrastructure. Implications of developing such anatomical and ultrastructural data of Sulsola species and biochemical characteristics reported in other C-4 species have been discussed.

• Korean Chemical Engineering Research
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• v.48 no.2
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• pp.178-184
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• 2010

The aim of this work is the fabrication of polyelectrolyte microcapsules composed of biocompatible polymers such as chitosan, heparin and alginate, to encapsulate the fluorescein isothiocyanate(FITC)-albumin, and to investigate the protein release behavior therefrom. Polyelectrolyte capsules with 4-layer structures could be prepared with biocompatible materials by oppositely charged adsorption using melamin-foramide as a template. Transmission electron microscope(TEM), scanning electron microscope(SEM) and optical microscope confirmed hollow capsule structures. Protein release before and after encapsulation was monitored with a UV-Vis spectrometer. Microcapsules have different behaviors depending on the kind of polyelectrolyte polymers, chitosan-heparin capsules or chitosan-alginate capsules. In conclusion, the polyelectrolyte multilayer shells can be switched between an open and closed state by means of tuning the pH value.

• Advances in nano research
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• v.4 no.1
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• pp.15-29
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• 2016

A low cost environmentally benign surface coating binder is highly desirable in the field of material science. In this report, castor oil based hyperbranched polyester/bitumen modified fly ash nanocomposites were fabricated to achieve the desired performance. The hyperbranched polyester resin was synthesized by a three-step one pot condensation reaction using monoglyceride of castor oil based carboxyl terminated pre-polymer and 2,2-bis (hydroxymethyl) propionic acid. Also, the bulk fly ash of paper industry waste was converted to hydrophilic nano fly ash by ultrasonication followed by transforming it to an organonano fly ash by the modification with bitumen. The synthesized polyester resin and its nanocomposites were characterized by different analytical and spectroscopic tools. The nanocomposite obtained in presence of 20 wt% styrene (with respect to polyester) was found to be more homogeneous and stable compared to nanocomposite without styrene. The performance in terms of tensile strength, impact resistance, scratch hardness, chemical resistance and thermal stability was found to be improved significantly after formation of nanocomposite compared to the pristine system after curing with bisphenol-A based epoxy and poly(amido amine). The overall results of transmission electron microscopic (TEM) analysis and performance showed good exfoliation of the nano fly ash in the polyester matrix. Thus the studied nanocomposites would open up a new avenue on development of low cost high performing surface coating materials.

• Advances in nano research
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• v.14 no.4
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• pp.391-397
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• 2023

This manuscript describes the one-step eco-friendly green fabrication of silver nanoparticles (AgNPs) through the in-situ bio-reduction of an aqueous solution of silver nitrate using Syzygium aromaticum leaf extract. UV-vis spectroscopy shows a characteristic SPR peak around 442 nm. FTIR spectroscopy showed that the AgNPs were capped with bioactive phyto-molecules. TEM images revealed oval and spherical particles with a mean diameter of ~12.6 nm. XRD analysis revealed crystalline and face-cantered cubic AgNPs. The phytosynthesized AgNPs showed broad-spectrum anti-microbial activity against two foodborne pathogenic bacteria, Listeria monocytogenes and Staphylococcus aureus. The AgNPs showed a prominent ability to inhibit biofilms formed by L. monocytogenes and S. aureus in laboratory conditions through a crystal violet assay. The results suggest that the AgNPs could be a novel nanotool to develop effective antimicrobial and anti-biofilm agents in food preservation.