• Journal of Sensor Science and Technology
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• v.25 no.4
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• pp.275-279
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• 2016

Chemical vapor deposited (CVD) polycrystalline graphene is widely used for various sensor application because of its extremely large surface-to-volume ratio. The electrical properties of CVD-graphene is significantly affected by the grain size and boundaries (GGBs), but evaluation of GGB of continuous monolayer graphene is difficult. Although several evaluation methods such as tunneling electron microscopy, confocal Raman, UV/ozone-oxidation are typically used, they still have issues in evaluation efficiency and accuracy. In this paper, we suggest an improved evaluation method for precise and simple GGB evaluation which is based on UV/ozone-oxidation and chemical etching process. Using this method, we could observe clear GGBs of CVD-graphene layers grown by different process conditions and statistically evaluate average grain sizes varying from $1.69{\sim}4.43{\mu}m$. This evaluation method can be used for analyzing the correlation between the electrical properties and grain size of CVD-graphene, which is essential for the development of graphene-based sensor devices.

• Korean Journal of Pharmacognosy
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• v.35 no.2 s.137
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• pp.105-109
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• 2004

The effect of MeOH extract of Cibotium barometz (or Cibaro) on nogo-A expression was studied by neurite cone collapse and neurite outgrowth assay. The degrees of mRNA expression of BDNF, GDNF, and Caspase-3 in nogo-A were also examined with SK-N-SH cell lines using RT-PCR and confocal microscopy methods. We have shown that Cibaro treatment inhibits nogo-A activation in SK-N-SH cell lines. It has been shown that Cibaro increases the expression rates of neurofilament and enhances neurite outgrowth in neuroblastoma cells as increasing the amount of Cibaro. It has been also shown that Cibaro increases the expression rates of BDNF, GDNF mRNA in neuroblastoma cells as increasing the amount of Cibaro. These results suggest that Cibaro induces neutrite outgrowth by nogo-A inactivation and is, therefore, crucial for the treatments against anaplastic disc and spinal neuronal anesthesia.

• Journal of Radiopharmaceuticals and Molecular Probes
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• v.5 no.2
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• pp.101-112
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• 2019

Herein, 2-nitroimidazole-fluorophore conjugates were synthesized by linking 2-nitroimidazole and FITC or RITC via thiourea bonds. The prepared derivatives were stable for 2 h in Dulbecco's modified Eagle's medium (DMEM) at 37 ℃. The novel conjugates were studied for their in vitro uptake under hypoxic conditions using U87MG and CT-26 cell lines, showing significantly higher uptakes in hypoxic than normoxic cells. Immunohistochemical analysis confirmed hypoxia in U87MG and CT-26 xenografted tumor tissues. Moreover, the prepared conjugates were evaluated by in vivo experiments after intravenous injection in U87MG and CT-26 xenografted mice. Hypoxia was confirmed by immunohistochemistry of the prepared derivatives with co-injected pimonidazole. Confocal microscopy of the prepared derivatives showed strong fluorescence in hypoxic tumor tissues correlated with the pimonidazole distribution. This suggested that the 2-nitroimidazole-fluorophore conjugates are promising optical imaging probes for tumor hypoxia and are promising substitutes for pimonidazole immunohistochemistry, which requires a multi-step procedure of incubation involving antibody, second antibody, dye, hydrogen peroxide, and multiple washing steps.

• Journal of the Korea Institute of Military Science and Technology
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• v.16 no.3
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• pp.390-397
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• 2013

Primary-cultured immune cells are widely used in research to elucidate the mechanism of inflammation including chemotaxis, production of reactive oxygen species, cytokine release and antigen presenting. Mice are one of the species of experimental animals commonly used for such studies. Immune cells can be isolated and cultured from various organs such as bone marrow, peritoneal cavity, lung, spleen. For elaborated experimental studies, immune cells should be elicited with inflammatory substances or proliferated in vitro with special media. This paper details methods of obtaining immune cells from various organs of mice and investigating immune mechanism using isolated immune cells. It contains standard protocols of isolating and culturing immune cells from bone marrow, peritoneal cavity and lymphoid organs. It also covers the methods of investigating immune mechanism such as ELISA, western blotting, confocal microscopy and ELISPOT assay. With the works in this study, we established the standardized isolation and analysis methods of primary-cultured immune cells.

• Journal of Microbiology and Biotechnology
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• v.20 no.8
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• pp.1185-1188
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• 2010

Previously, papiliocin was isolated from the swallowtail butterfly Papilio xuthus and its antimicrobial activity was suggested. In this study, the antifungal mechanism of papiliocin against Candida albicans was investigated. Confocal laser scanning microscopy (CLSM) and 1,6-diphenyl-1,3,5-hexatriene (DPH) fluorescence analysis indicated that papiliocin disturbed the fungal plasma membrane. Moreover, the assessment of the release of FITC-dextran (FD) from liposomes further demonstrated that the antifungal mechanism of papiliocin could have originated from the pore-forming action and that the radius of the pores was presumed to be anywhere from 2.3 to 3.3 nm.

• Advances in environmental research
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• v.7 no.1
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• pp.39-52
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• 2018

Direct membrane filtration (DMF) of wastewater has many advantages over conventional biological wastewater treatment processes. DMF is not only compact, but potentially energy efficient due to the lack of biological aeration. It also produces more biosolids that can be used to produce methane gas through anaerobic digestion. Most of ammoniacal nitrogen in wastewater is preserved in effluent and is used as fertilizer when effluent is recycled for irrigation. In this study, a technical feasibility of DMF was explored. Organic and nitrogen removal efficiencies were compared between DMF and membrane bioreactor (MBR). Despite the extremely high F/V ratio, e.g., $14.4kg\;COD/m^3/d$, DMF provided very high COD removal efficiencies at ~93%. Soluble microbial products (SMP) and extracellular polymeric substances (EPS) were less in DMF sludge, but membrane fouling rate was far greater than in MBR. The diversity of microbial community in DMF appeared very narrow based on the morphological observation using optical microscope. On the contrary, highly diverse microbial community was observed in the MBR. Microorganisms tended to form jelly globs and attach on reactor wall in DMF. FT-IR study revealed that the biological globs were structurally supported by feather-like materials made of secondary amines. Confocal laser scanning microscopy (CLSM) study showed microorganisms mainly resided on the external surface of microbial globs rather than the internal spaces.

• Journal of Microbiology and Biotechnology
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• v.14 no.3
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• pp.450-455
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• 2004

A reducing glucose-carrying polymer, called poly [3-O-(4'-vinylbenzyl)-D-glucose］(PVG), was interacted with HepG2 cells including a type-l glucose transporter (GLUT-1) on the cell membrane. The cooperative interaction between a number of GLUT-1s and a number of reducing 3-O-methyl-D-glucose moieties on the PVG polymer chain was found to be responsible for the increase in the interaction with HepG2 cells. The affinity between the cells and the PVG was studied using RITC-labeled glycopolymers. The specific interaction between the GLUT-1 on HepG2 cells and the PVG polymer carrying reducing glucose moieties was suppressed by the inhibitors, phloretin, phloridzin, and cytochalasin B. Direct observation by confocal laser microscopy with the use of RITC-labeled PVG and pretreatment of HepG2 cells with the inhibitors demonstrated that the cells interacted with the soluble form of the PVG polymer via GLUT-1, while fluorescence labeling of the cell surface was prevented after pretreatment with the inhibitors of GLUT-1.

• Journal of Korean Neurosurgical Society
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• v.41 no.1
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• pp.30-38
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• 2007

Objective : To elucidate the role of aquaporin-4[AQP4] in cerebral edema formation, we studied the expression and subcellular localization of AQP4 in astrocytes after focal cerebral ischemia. Methods : Cerebral ischemia were induced by permanent middle cerebral artery[MCA] occlusion in rats and estimated by the discoloration after triphenyltetrazolium chloride[TTC] immersion. Change of AQP4 expression were evaluated using western blot. Localization of AQP4 was assessed by confocal microscopy and its interaction with ${\alpha}-syntrophin$ was analyzed by immunoprecipitation. Results : After right MCA occlusion, the size of infarct and number of apoptotic cells increased with time. The ratio of GluR1/GluR2 expression also increased during ischemia. The polarized localization of AQP4 in the endfeet of astrocytes contacting with ventricles, vessels and pia mater was changed into the diffuse distribution in cytoplasm. The interactions of AQP4 and Kir with ${\alpha}-syntrophin$, an adaptor of dystrophin complex, were disrupted by cerebral ischemia. Conclusion : The deranged spatial buffering function of astrocytes due to mislocalized AQP4/Kir4.1 channel as well as increased assembly of $Ca^{2+}$ permeable AMPA receptors might contribute to the development of edema formation and the excitotoxic neuronal cell death during ischemia.

• Journal of Microbiology and Biotechnology
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• v.18 no.2
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• pp.328-333
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• 2008

A series of pep tides binding to the HCV NS5B polymerase was selected from phage display peptide libraries. A conserved motif of Ser-Arg-X-Arg/Leu was identified among the selected peptides, and Pep2 (Trp-Ser-Arg-Pro-Arg-Ser-Leu) was chosen for further characterization. The binding of Pep2 to HCV NS5B in vivo was shown by a yeast two-hybrid assay and by subcellular colocalization analysis using immunofluorescence confocal microscopy. The in vitro interaction was also confirmed by GST pulldown assay. The replication of the HCV 1b subgenomic replicon was efficiently inhibited by the presence of the peptide. By using a subtractive biopanning against Pep2, the binding site of the peptide was mapped at the pocket of Pro388 to Pro391 in the thumb subdomain of the polymerase. A yeast two-hybrid analysis using Pro388Ala and Pro391Ala mutants of NS5B confirmed the binding.

• Journal of Microbiology and Biotechnology
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• v.19 no.9
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• pp.1028-1033
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• 2009

In this study, the dynamics of living cells (LC) and dead cells (DC) in a laboratory-scale biofilm membrane bioreactor for waste gas treatment was examined. Toluene was used as a model pollutant. The bacterial cells were enumerated as fluoromicroscopic counts during a 140 operating day period using BacLight nucleic acid staining in combination with epifluorescence and confocal laser scanning microscopy (CSLM). Overall, five different phases could be distinguished during the biofilm development: (A) cell attachment, (B) pollutant limitation, (C) biofilm establishment and colonization, (D) colonized biofilm, and (E) biofilm erosion. The bioreactor was operated under different conditions by applying different pollutant concentrations. An optimum toluene removal of 89% was observed at a loading rate of 14.4 kg $m^{-3}d^{-1}$. A direct correlation between the biodegradation rate of the reactor and the dynamics of biofilm development could be demonstrated. This study shows the first description of biofilm development during gaseous toluene degradation in MBR.