• The Korean Journal of Physiology and Pharmacology
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• v.17 no.1
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• pp.57-64
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• 2013

Cells can resist and even recover from stress induced by acute hypoxia, whereas chronic hypoxia often leads to irreversible damage and eventually death. Although little is known about the response(s) to acute hypoxia in neuronal cells, alterations in ion channel activity could be preferential. This study aimed to elucidate which channel type is involved in the response to acute hypoxia in rat pheochromocytomal (PC12) cells as a neuronal cell model. Using perfusing solution saturated with 95% $N_2$ and 5% $CO_2$, induction of cell hypoxia was confirmed based on increased intracellular $Ca^{2+}$ with diminished oxygen content in the perfusate. During acute hypoxia, one channel type with a conductance of about 30 pS (2.5 pA at -80 mV) was activated within the first 2~3 min following onset of hypoxia and was long-lived for more than 300 ms with high open probability ($P_o$, up to 0.8). This channel was permeable to $Na^+$ ions, but not to $K^+$, $Ca^+$, and $Cl^-$ ions, and was sensitively blocked by amiloride (200 nM). These characteristics and behaviors were quite similar to those of epithelial sodium channel (ENaC). RT-PCR and Western blot analyses confirmed that ENaC channel was endogenously expressed in PC12 cells. Taken together, a 30-pS ENaC-like channel was activated in response to acute hypoxia in PC12 cells. This is the first evidence of an acute hypoxia-activated $Na^+$ channel that can contribute to depolarization of the cell.

• Journal of the Korean Wood Science and Technology
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• v.42 no.4
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• pp.460-466
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• 2014

To evaluate wood charcoal as raw material for mineral water production, dissolution of inorganic ions from charcoal to water, pH and adsorption ability of chlorine in water were investigated as main variables. More potassium ion was dissolved in water as higher temperature manufactured charcoal but other ions showed no difference with different charcoal making temperatures. Highest dissolved cation was potassium followed by calcium and sodium. Among wood species, charcoal from Quercus variabilis and Platanus occidentalis showed significantly higher potassium content in water than that of larch, red pine and white pine. Other cations had similar pattern to the potassium but their difference was not apparent as much as potassium. pH value of water treated with charcoal was higher for wood charcoals from Platanus occidentalis (pH 8.5) and Quercus variabilis (pH 8.4) which contained higher inorganic cations. In chlorine removal in water by charcoal, all wood charcoals showed greater chlorine removal than that of the control, but softwood charcoals resulted in higher removal than those of hardwoods. There was no significant difference in the dissolution of cations and pHs between particle charcoal and whole charcoal. With easy of control, whole charcoal is better for mineral water making raw material than particle charcoal does.

• The Journal of Advanced Prosthodontics
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• v.7 no.1
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• pp.56-61
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• 2015

PURPOSE. The purpose of this study was to evaluate the effects of the surface treatment and shape of the dental alloy on the composition of the prosthetic work and its metallic ion release in a corrosive medium after casting. MATERIALS AND METHODS. Orion Argos (Pd-Ag) and Orion Vesta (Pd-Cu) were used to cast two crowns and two disks. One of each was polished while the other was not. Two as-received alloys were also studied making a total of 5 specimens per alloy type. The specimens were submersed for 7 days in a lactic acid/sodium chloride solution (ISO standard 10271) and evaluated for surface structure characterization using SEM/EDAX. The solutions were quantitatively analysed for the presence of metal ions using ICP-MS and the results were statistically analysed with one-way ANOVA and a Tukey post-hoc test. RESULTS. Palladium is released from all specimens studied (range $0.06-7.08{\mu}g{\cdot}cm^{-2}{\cdot}week^{-1}$), with the Pd-Cu alloy releasing the highest amounts. For both types of alloys, ion release of both disk and crown pairs were statistically different from the as-received alloy except for the Pd-Ag polished crown (P>.05). For both alloy type, disk-shaped pairs and unpolished specimens released the highest amounts of Pd ions (range $0.34-7.08{\mu}g{\cdot}cm^{-2}{\cdot}week^{-1}$). Interestingly, in solutions submerged with cast alloys trace amounts of unexpected elements were measured. CONCLUSION. Shape and surface treatment influence ion release from dental alloys; polishing is a determinant factor. The release rate of cast and polished Pd alloys is between $0.06-0.69{\mu}g{\cdot}cm^{-2}{\cdot}week^{-1}$, which is close to or exceeding the EU Nickel Directive 94/27/EC compensated for the molecular mass of Pd ($0.4{\mu}g{\cdot}cm^{-2}{\cdot}week^{-1}$). The composition of the alloy does not represent the element release, therefore we recommend manufacturers to report element release after ISO standard corrosion tests beside the original composition.

• KSBB Journal
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• v.11 no.5
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• pp.606-612
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• 1996

A specific ammino auid in a mixture can be crystallized inside an ion exchange column when displacer concentration is high enough to concentrate the amino acid in a pure band beyond its solubility limit. Glutamic acid formpd a discrete crystal layer in a cation exchanger column by operating displacement development mode and using a high concentration of displacer NaOH. The glutamic acid crystal formed was eluded from the column with the effluent stream and collected in a fraction collector. When 1.0 M of NaOH was used as a displacer, more than 60% of the loaded glutamic acid was recovered as crystal. The continuous crystallization and dissolution of crystal occurred, resulting in apparent movement of the crystal along the column without clogging or pressure increase. NaOH was proved a better displacer than NaCl because hydroxide ions neutralized hydrogen ions released from the resin and thus reduced the number of hydrogen ion competing with sodium ion for re-adsorption. The displacement development process coupled with crystallization provided higher concentration and recovery of glutamic acrid than conventional chromatography.

• Journal of the Korean Electrochemical Society
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• v.3 no.3
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• pp.162-168
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• 2000

The influence of phenolsulfunate concentrations on electroplating characteristics and electrochemical behaviors was investigated with a viewpoint of electrolyte aging using the circulation cell and potentiostate And comparison of tinplate coating appearance such as glossiness and Image clarify has been also studied with varying of phenolsulfonic acid (PSA) solutions. As the aging of electrolyte proceeded, the limiting current density was moved to a lower current density region by the limitation of mass transfer, and higher phenolsulfunate concentrations resulted in the narrower optimum current density range and deterioration of coating surface of tinplates. The difference of the limiting current density was not remarkable with increasing electrolyte temperature. Thus the electrolyte aging was attributed to the limitation of thermally-activated process such as mass transfer of reducible ions. It has also been considered that the accumulation of phenolsulfonate suppressed normal electrotinning reaction by reducing the mobility of stannous ions, taking into account of the smaller effect of electrolyte aging. Experiments showed similar polarization behavior between the electrolyte of high phenolsufonate solution and the aged one, which comes to conclude that the accumulation of phenolsulfonate is one of the major causes of electrolyte aging.

• Applied Chemistry for Engineering
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• v.33 no.6
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• pp.581-587
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• 2022

The leather industry generates a large amount of hazardous leather waste of various types every year. Among them, shaving scrap is difficult to recycle because it contains chromium ions. Many studies in recent years have shown that shaving scraps can be processed into various types of valuable products, such as adsorbent, filler, and poultry feed. In this study, collagen peptides were extracted from shaving scraps and structurally modified to be developed as new materials with improved physicochemical properties. First, the chromium ions contained in the shaving scraps were removed using a sodium hydroxide solution, and purified through concentration and low-temperature crystallization. The purified collagen peptide was used to prepare the powder using a spray dryer. The extracted collagen peptides were structurally modified by introducing double bonds by reacting with methacrylic anhydride (MAA), and the product was confirmed by ¹H NMR spectroscopy. Next, a copolymer was prepared by redox polymerization of the modified collagen peptide (MCP) and 2-ethylhexyl acrylate (2-EHA). The structure of the copolymer was qualitatively confirmed by FT-IR. In conclusion, this study confirmed that collagen peptides can be extracted from shaving scrap and converted into new eco-friendly materials through certain treatments.

• Parasites, Hosts and Diseases
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• v.54 no.1
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• pp.21-29
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• 2016

The sodium hydrogen exchanger 1 (NHE1), which functions in maintaining the ratio of $Na^+$ and $H^+$ ions, is widely distributed in cell plasma membranes. It plays a prominent role in pH balancing, cell proliferation, differentiation, adhesion, and migration. However, its exact subcellular location and biological functions in Toxoplasma gondii are largely unclear. In this study, we cloned the C-terminal sequence of T. gondii NHE1 (TgNHE1) incorporating the C-terminal peptide of NHE1 (C-NHE1) into the pGEX4T-1 expression plasmid. The peptide sequence was predicted to have good antigenicity based on the information obtained from an immune epitope database. After induction of heterologous gene expression with isopropyl-b-D-thiogalactoside, the recombinant C-NHE1 protein successfully expressed in a soluble form was purified by glutathione sepharose beads as an immunogen for production of a rabbit polyclonal antiserum. The specificity of this antiserum was confirmed by western blotting and immunofluorescence. The antiserum could reduce T. gondii invasion into host cells, indicated by the decreased TgNHE1 expression in T. gondii parasites that were pre-incubated with antiserum in the process of cell entry. Furthermore, the antiserum reduced the virulence of T. gondii parasites to host cells in vitro, possibly by blocking the release of $Ca^{2+}$. In this regard, this antiserum has potential to be a valuable tool for further studies of TgNHE1.

• The Journal of Internal Korean Medicine
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• v.22 no.1
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• pp.45-52
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• 2001

Purpose : This study is to find out the Ginseng Radix extract on rats nephrotoxicity when the rates were induced by Cs A. Methods : The experimental animals were divided into 3 groups and treated as follows: nothing was given to Sample A, Sample B was given normal saline after an I.V. injection of Cs A, and Sample C was given Ginseng Radix extract after a Cs A injection. The groups were observed for 14 days. After the prescription of the medicines, the following levels were tested: serum BUN, creatinine, total protein, sodium, potassium, and chloride ions. Results : 1. Changes in serum level. The levels of GPT, GOT, and BUN were significantly reduced in the experimental group when compared with those of the control group. The total protein level showed significant elevation when compared with those of the control group. The chloride level in the serum in the sample group was insignificantly reduced. The creatinine level was insignificantly increased. The Potassium level decreased, mildly. The Sodium and The Potassium levels in the serum in the sample group showed insignificantly lower levels than those of the control group. 2. Changes in the urine level. Urine specific gravity showed a significant increase, on the 14th day, in the experimental group when compared with that of the control group. The urinary ceatinine levels showed and insignificant increase, followed by an insignificant decrease. Conclusion : It can be inferred that Ginseng Radix may improve nephrotoxicity and hepatoxicity in rats when induced by Cyclosporin A.

• Journal of the Korean Chemical Society
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• v.19 no.4
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• pp.225-232
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• 1975

The elution behaviour of molybdate and tungstate through anion exchange column has been studied at the various pH. A discussion is made to evaluate the equilibrium constants of the polymerization of these acids comparing with the behaviour of chromate ion and dichromate ion. The eqailibrium constants found at $20^{\circ}$ are $K = 4{\times}10^{53} for 7MoO_4^{2-} + 8H^+ {\longleftrightarrow} Mo7O_{24}^{6- }+ 4H_2O$$ K = 3{\times}10^{54} for 6WO_4^{2-} + 7H^+ {\longleftrightarrow} HW6O_{21}^{5-} + 7H_2O$ referring to this results the conditions of separation of tungstate and molybdate are obtained. iThe quantitative separations of carbonate, molybdate and tungstate from the pregnant solution have been established by anion exchange chromatography, using the $22 cm{\times}44.27 cm^2$ column of Rexyn 201. The optimum eluents for the quantitative separation of those ions are as follows; 0.2M solution of sodium chloride at pH 8 for carbonate, the mixture of 0.5 M ammonium chloride and 0.05 M sodium sulfate at pH 5 for molybdate and 0.5 M solution of ammonium chloride at pH 10 for tungstate. Tungstate is directly recovered from the pregnant solution as a form of ammonium paratungstate, by eluting with ammonium chloride solution.

• Korean Journal of Agricultural Science
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• v.25 no.1
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• pp.131-137
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• 1998

The cellulase components were partially purified from the culture filtrate of the alkalophilic bacterium Pseudomonas sp. AC-711 and its enzymatic properties were characterized. The specific activity of the purified major enzyme component was 3.5 units/mg protein as carboxymethyl cellulase and the yield was 23% of the total activity of the culture broth. The molecular weight of the component was 46,000 and the Km and Vmax on CMC were determined as $15.4mg\;mL^{-1}$ and $4.17{\mu}moles\;mL^{-1}\;min^{-1}$, respectively. The enzyme was stable at the temperatures below $60^{\circ}C$ and at the pH range of 4.0~11.0, and the optimal temperature and pH were $60^{\circ}C$ and pH 8.0, respectively. The enzyme activity was not significantly affected by the common surfactants (concentration: 0.05%) such as ${\alpha}$-olefin sulfonate, linear alkylbenzene sulfonate, sodium dodecyl sulfonate, hexadecyltrimethylammonium bromide and Tween 80. The enzyme was activated by the metal ions such as $Ca^{2+}$, $Cu^{2+}$, $Co^{2+}$, whereas inhibited by $Hg^{2+}$ and $Zn^{2+}$. The enzyme exhibited relatively high activity toward amorphous CMC as compared with crystalline substrates such as filter paper and avicel.