• Biomolecules & Therapeutics
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• v.10 no.4
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• pp.293-302
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• 2002

The classical concept for iron uptake into mammalian cells has been the endocytosis of transferrin( $T_{f}$ )-bound F $e^{3+}$ via the $T_{f}$ - $T_{f}$ receptor cycle. In this case, we could not explain the uptake of F $e^{2＋}$ ion and the export of iron from endosome. Studies on iron transport revealed that other transport system exists in epithelial cells of the intestine. One of non- $T_{f}$ -receptor-mediated transport systems is Nramp2/DMT1/DCT1 which transports M $n^{＋＋}$, $Mg^{＋＋}$, Z $n^{＋＋}$, $Co^{＋＋}$, N $i^{＋＋}$ or C $u^{＋＋}$ ion as well as F $e^{+2}$ ion. DMT1 was cloned from intestines of iron-deficient rats and shown to be a hydrogen ion-coupled iron transporter and a protein regulated by absorbed dietary iron. DMT1 is founded in other cells such as cortical and hippocampal glial cells as well as endothelial cells in duodenum. Two F $e^{3+}$ ion bound to transferrin( $T_{f}$ ) are taken up via the $T_{f}$ - $T_{f}$ receptor cycle in the intestinal epithelial cell. F $e^{3+}$ in endosome was converted to F $e^{2＋}$ ion, and then exported to cytosol via DMT1. F $e^{2＋}$ ion is taken up into cytosol via DMT1. Several other transporters such as FET, FRE, CCC2, AFT1, SMF, FTR, ZER, ZIP, ZnT and CTR have been reported recently and dysfunction of the transporters are related with diseases containing Wilson's disease, Menkes disease and hemochromatosis. Evidences from several studies strongly suggest that DMT1 is the major transporter of iron in the intestine and functions critically in transport of other metal ions.

• Proceedings of the Korean Biophysical Society Conference
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• 2001.06a
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• pp.39-39
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• 2001

Many physiological processes of plant cells, such as nutrient uptake, salt tolerance, and cell enlargement, are mediated by ion transports across the plasma membrane. H$^{＋}$-ATPases on both plasma and vacuolar membranes play major roles on active transports and ion channels mediate passive transports of various ions. It has been known that these proteins involved in cellular osmotic regulation and salt tolerance in the salt-accumulated soils.(omitted)

• The Korean Journal of Ecology
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• v.6 no.4
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• pp.243-249
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• 1983

Absorption pattern of potassium, calcium, phosphate and nitrate ions, and the pH change during ion-absorption at pH 3.0-11.0 by Oryza sativa L. were studied to investigate indirectly the evidence of H^+-efflux by ATPase. The rice seedlings which were grown either in $L^{\circ} -dark or in L^+-sunlight$, were used both in each ion-absorption to compare with one another. The uptake rate of these ions appeared to favor more in $L^+than in L^{\circ}$, over all range in pH, nearly with the same pattern. The absorption of potassium resulted in bell shape and that of calcium increased linearly to the alkali range. The shape of phosphate-absorption showed nearly the t-distribution curve with high value in acid range and the uptake of nitrate resulted in the dual peaks, but higher in acid range. The pH of the external solution changed from the range of 3.5-11.0 to 3.5-7.0 after lhr-absorptioin, and further acidified after 3hr-absorption. It is suggested that the pH change of the external solution be affected by $ H^+-efflux$ which may be caused by the ATP-hydrolysis.

• Polymer(Korea)
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• v.26 no.5
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• pp.575-581
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• 2002

Heterogeneous ion exchange membranes were prepared by mixing polyethylene as matrix with bead and fibrous anionic ion exchangers at different mixing ratio. Generally, ion exchange capacities were increased with increasing the ratio of the fibrous ion exchanger content. The highest ion exchange capacity of the membrane was 1.86 meq/g at 30wt% IXF (ion exchange fiber) in the membrane. The water uptake, fixed ion concentration, and ion transport number of the membrane increased with increasing the content of the fibrous ion exchanger. However, the electrical resistivity of the membrane was decreased with increasing the content of the fibrous ion exchanger. The lowest electrical resistivity of 5$\Omega$/$\textrm{cm}^2$ was observed at 30 wt%of IXF.

• Biotechnology and Bioprocess Engineering:BBE
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• v.10 no.2
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• pp.109-114
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• 2005

Ion fluxes across the plasma membrane activated by 1 mM $Ce^{4+}$, cell apoptosis and taxol biosynthesis in suspension cultures of Taxus cusp/data were studied. The extracellular pH sharply decreased upon the addition of 1 mM $Ce^{4+}$, then increased gradually and exceeded the initial pH value over a time period of 12 h. The extracellular $Ca^{2+}$ concentration decreased within the first 3 h after the addition of $Ce^{4+}$, then gradually decreased to one third of initial value in control at about 72 h and remained unchanged afterwards. Experiments with an ion channel blocker and a $Ca^{2+}$-channel blocker indicated that the dynamic changes in extracellular pH and the $Ca^{2+}$ concentration resulted from the $Ce^{4+}$-induced activation of W uptake and $Ca^{2+}$ influx across the plasma membrane via ion channels. A pretreatment of the ion channel blocker initiated $Ce^{4+}$-treated cells to undergo necrosis, and the prior addition of the $Ca^{2+}$-channel blocker inhibited $Ce^{4+}$-induced taxol biosynthesis and apoptosis. It is thus inferred that W uptake is necessary for cells to survive a $Ce^{4+}$-caused acidic environment and is one of the mechanisms of $Ce^{4+}$-induced apoptosis. Furthermore, the $Ca^{2+}$ influx across the plasma membrane mediated both the $Ce^{4+}$-induced apoptosis and taxol biosynthesis.

• Journal of Environmental Science International
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• v.20 no.11
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• pp.1437-1445
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• 2011

The adsorption performance of lead ion was studied using five zeolites (Na-P1, sodalite (SOD), analcime (ANA), nepheline hydrate (JBW), cancrinite (CAN)) synthesized from Jeju scoria. The adsorption performances of lead ion decreased in the order of Na-P1 > SOD > ANA > JBW > CAN. These results showed that the synthetic zeolite with a higher cationic exchange capacity showed a higher adsorption performance. The uptake of lead ion by synthetic zeolites were described by Freundlich model better than Langmuir model. The adsorption kinetics of lead ion by synthetic zeolites fitted the pseudo 2nd order kinetics better than pseudo 1st order kinetics. The effective diffusion coefficients of lead ion by synthetic zeolites were ten times higher than the zeolite A synthesized from coal fly ash.

• Nuclear Engineering and Technology
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• v.55 no.10
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• pp.3665-3676
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• 2023

The use of ion exchange resins to remove ionic impurities from solution is prevalent in industrial process systems, including in the primary heat transport system (PHTS) purification circuit of nuclear power plants. Despite its extensive use in the nuclear industry, our general understanding of ion exchange cannot fully explain the complex chemistry in ion exchange beds, particularly when operated at or near their saturation limit. This work investigates the behaviour of mixed-bed ion exchange resin, saturated with species representative of corrosion products in a CANDU (Canadian Deuterium Uranium) reactor PHTS, particularly with respect to iron chemistry in the resin bed and the removal of lithium ions from solution. Experiments were performed under deaerated conditions, analogous to normal PHTS operation. The results show interesting iron chemistry, suggesting the hydrolysis of cation resin bound ferrous species and the subsequent formation of either a solid hydrolysis product or the soluble, anionic Fe(OH)₃^-.

• Transactions of the Korean hydrogen and new energy society
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• v.28 no.2
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• pp.144-149
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• 2017

A proton-conducting bisphenylpropaned sulfonated fluorinated blockcopolymer (BPSFBC) was synthesized. Five kinds of polymer electrolyted composite membranes were preparated by incorporating silica ($SiO_2$) with various weight ratio. And their characteristics were investigated by FT-IR (fourier transform infrared), $^1H-NMR$ ($^1H$ nuclear magnetic resonance), TGA (thermogravimetric analysis), water uptake, FE-SEM (field emission scanning electron microscopes), and ion conductivity properties. The water uptake and ion conductivity were increased until 9 wt% $SiO_2$, and then decreased. The maximum proton conductivity equal to $52mScm^{-1}$ was measured for the BPSFBC/$SiO_2$-9 composite membrane at $90^{\circ}C$ and 100% relative humidity. From the measured results, it is distinct that the manufactured composite membrane BPSFBC/$SiO_2$-9 can be considered as a polymer membrane suitable for a fuel cell electrolyte.

• Korean Chemical Engineering Research
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• v.49 no.1
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• pp.69-74
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• 2011

In this study, it was prepared for nanofiber with high impact polystyrene(HIPS). HIPS is able to crosslinking after electrospinning with crosslinking agent and it could overcome brittle characteristics of polystyrene(PS). After thermal crosslinking, HIPS nanofiber was sulfonated by sulfuric acid. It was investigated FT-IR, XPS, water uptake, ion exchange capacity(IEC), SEM, and contact angle. According to the result of FT-IR and XPS, it was increased due to introduce the hydrophilic group($SO_3H$) in the HIPS nanofiber. The highest water uptake and IEC were 75.6%, 2.67 meq/ g at 120 min sulfonation time with 7.5 wt% DVB.

• Biomolecules & Therapeutics
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• v.16 no.3
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• pp.219-225
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• 2008

Taurine is the most abundant amino acid in many tissues and is found to be enhancing the bone tissue formation or inhibits the bone loss. Although it is reported that taurine reduces the alveolar bone loss through inhibiting the bone resorption, its functions of taurine and expression of taurine transporter (TauT) in bone have not been identified yet. The purpose of this study is to clarify the uptake mechanism of taurine in osteoblast using mouse osteoblast cell lines. In this study, mouse stromal ST2 cells and mouse osteoblast-like MC3T3-E1 cells as osteoblast cell lines were used. The activity of taurine uptake was assessed by measuring the uptake of [$^3H$]taurine in the presence or absence of inhibitors. TauT mRNA was detected in ST2 and MC3T3-E1 cells. [$^3H$]Taurine uptake by these cells was dependent on the presence of extracellular calcium ion. The [$^3H$]taurine uptake in ST2 cells treated with 4 mM calcium was increased by 1.7-fold of the control which was a significant change. In contrast, in $Ca^{++}$-free condition and L-type calcium channel blockers (CCBs), taurine transport to osteocyte was significantly inhibited. In oxidative stress conditions, [$^3H$]taurine uptake was decreased by TNF-$\alpha$ and $H_2O_2$. Under the hyperosmotic conditions, taurine uptake was increased, but inhibited by CCBs in hyperosmotic condition. These results suggest that, in mouse osteoblast cell lines, taurine uptake by TauT was increased by the presence of extracellular calcium, whereas decreased by CCBs and oxidative stresses, such as TNF-$\alpha$ and $H_2O_2$.