• Proceedings of the Ginseng society Conference
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• 2002.10a
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• pp.545-555
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• 2002

Ginsenosides of 20(S)-protopanaxadiol and 20(S)-protopanaxatriol classification including the aglycones, PD, PI and ginsenosides Rh2, Rhl were shown to posses characteristic effects on proliferation of THP-l human leukaemia cells. A similar result was not apparent for ginsenoside Rg3 or dexamathasone. The concentration to inhibit $50\%$ of cells $(LC_{50})$ for PD, Rh2, PI and Rhl were 13 ${\mu}g/mL,\;15{\mu}g/mL,\;19{\mu}g/mL\;and\;210\;{\mu}g/mL$ respectively. Cell cycle analysis showed apoptosis with PD and PI treatment of THP-1 cells resulting in a build up of sub-G1 cells after 24, 48 and 72 hours of treatment. Rh2, and dexamathasone treatments also increased apoptotic cells after 24 hours, where as Rhl did not. After 48 and 72 hours Rh2, Rhl and dexamathasone similarly increased apoptosis, but these effects were significantly (P<0.05) lower than observed for both PD and PI treatments. Furthermore, treatments that produced the largest build up of apoptotic cells were also found to have the largest release of lactate dehydrogenase (LDH). It can be concluded from these studies that the presence of sugars to PD and PI aglycone structure reduces the potency to induce apoptosis, and alternately alter membrane integrity. These cytotoxic effects to THP-l cells were different from dexamethasone.

• Proceedings of the Membrane Society of Korea Conference
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• 1994.10a
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• pp.8-11
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• 1994

Disposal of hazardous ions in the aqueous streams is a significant industrial waste problem.. Waste streams from electronics, electroplating, and photographic industries contain metal ions such as copper, nickel, zinc, chromium(IV), cadmium, aluminum, silver, and gold, amongst others in various aqueous solutions such as sulfates, chlorides, fluorocarbons, and cyanides. Typical plating solutions having similar compositions are listed in Table 1. Spent process streams in catalyst manufacturing facilities also contain precious metals such as Ag, Pt, and Pd. Developing an effective recovery process of these metal ions for reuse is important.

• Bulletin of the Korean Chemical Society
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• v.24 no.3
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• pp.291-294
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• 2003

A highly interferent-resistive membrane, poly-5-amino-1-naphthol (poly-5A1N), underlied beneath enzymeembedded poly-1,3-phenylendiamine (poly-m-PD) network for miniturized continuous monitoring glucose sensors. The enzyme layer was prepared from a mixed solution of glucose oxidase (GOx) and m-PD monomer by simple electrolysis. The mass change of poly-5A1N was monitored by electrochemical quartz crystal microbalance (EQCM) in situ and the corresponding thickness was measured. Successive electropolymerization of poly-5A1N and poly-m-PD create a several tens nm-thick bilayer showing excellent selectivity for $H_2O_2$ and low activity loss of immobilized enzymes.

• Bulletin of the Korean Chemical Society
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• v.24 no.4
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• pp.489-493
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• 2003

2-Mercaptobenzothiazole was used as a highly selective and efficient carrier for the uphill transport of silver ion through a chloroform bulk liquid membrane. In the presence of thiosulfate ion as a suitable metal ion acceptor in the receiving phase, the amount of silver transported across the liquid membrane after 180 min was 90 ± 3.0%. The selectivity and efficiency of silver ion transported from aqueous solutions containing equimolar mixtures of $Zn^{2+}, Cu^{2+}, Co^{2+}, Ni^{2+}, Cd^{2+}, Pb^{2+}, Bi^{3+}, Fe^{2+}, Fe^{3+}, Pd^{2+}, Mn^{2+}, Hg^{2+}, Sn^{2+}, Ca^{2+}, Mg^{2+}, K^+, Na^+ and Li^+$ were investigated.

• Journal of the Korean Electrochemical Society
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• v.15 no.1
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• pp.12-18
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• 2012

The prohibitively high cost of Pt catalyst might be the biggest barrier for the commercialization of proton exchange membrane fuel cells (PEMFC) of which wide application is expected. Worldwide research efforts for the development of alternative to Pt oxygen reduction reaction (ORR) catalyst are made recently. One of the important considerations in the catalyst development is durability issue as well as economic aspect. From this point of view, platinum group metals (PGM) except Pt can be a candidate for replacing Pt catalyst because the material properties and the catalytic activity of PGM are expected to be similar to Pt. In contrast to Ir, Rh and Os to which not so much attention has been paid as an ORR catalyst, Pd that is most similar to Pt in terms of material properties and catalytic activity and Ru that is in the form of chalcogenide have been studied intensively. Activity comparison between non-Pt and Pt oxygen reduction catalysts by half cell test using RDE (rotating disk electrode) or PEMFC MEA (membrane electrode assembly) operation indicates that Pd-based catalysts show the most similar activity to Pt. In this paper we analyze the composition of PGM ORR catalyst in literature to promote the development of non-Pt ORR catalyst.

• Journal of the Korean Electrochemical Society
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• v.5 no.4
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• pp.226-231
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• 2002

Power densities produced by the permeation of methanol through membranes were directly measured by inserting the membrane in front of anode in a membrane-electrode-assembly of a direct methanol fuel cell (DMFC). The power density was closely related to the loss of power in the DMFC and was strongly affected by temperature. As the cell temperature was increased, the power density resulting from methanol crossover was increased. The increase in methanol crossover had be attributed to diffusion caused or affected by temperature. Methanol crossover a major effect on the performance of a DMFC at a relatively low temperature with $26\%\;loss\;at\;30^{\circ}C$. In order to reduce methanol crossover, a conventional Nafion membrane was modified by the incorporation of Pt or Pd. The reduction in methanol crossover was investigated in these modified membranes by our cell performance measurement. Pt and Pd particles incorporated in the Nafion membranes block methanol pathway and prevent methanol transport through the membranes, which was proved by combining with liquid chromatography.

• Journal of Hydrogen and New Energy
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• v.29 no.3
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• pp.260-266
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• 2018

To enhance catalyst activity of the palladium (Pd) towards oxygen reduction reaction (ORR), iridium (Ir) and yttrium (Y) were alloyed by polyol method. Due to the low reduction potential of Y, it is hard to reduce Y ion completely by polyol method. In XPS spectra, the binding energy of the Pd is shifted to a lower value, which indicates the d-electron of Pd is filled by the electron from the Y. And other phases of Y are observed by the XPS. Among the catalysts, the $Pd_4IrY_{0.1}/C$ showed the best activity towards ORR, which indicates the metallic Y is effective for improving the catalytic activity. Thus, for further enhancing ORR activity, the novel method for complete reduction of Y is needed.

• Journal of Ginseng Research
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• v.17 no.2
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• pp.131-134
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• 1993

Panaxadiol (PD) from Korean red ginseng C.A. Meyer did not control the concentration of cytosolic free $Ca^{2+}$ influxes by thrombin (5 $\mu$/ml). However, PD strongly inhibited the synthesis of thromboxane. $A_2$ (TX$A_2$) in the aggregation of human platelets induced by thrombin (5 $\mu$/ml). These rexults suggest that PD blocks the any Pathway transforming to TX$A_2$ from arachidonic acid (AA) which release out of plasma membrane phospholipids by $Ca^{2+}$-dependent phospholipase C or phospholipase $A_2$. It may be also concluded that PD has the antiplatelet function by inhibiting the synthesis of TX$A_2$, which known to be the potent stimulator of the aggregation of human platelet.

• Proceedings of the Korean Radioactive Waste Society Conference
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• 2009.06a
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• pp.419-419
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• 2009

• Biomedical Science Letters
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• v.17 no.2
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• pp.167-171
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• 2011

[ ${\alpha}$ ]synuclein (${\alpha}$-syn) is implicated in the pathogenesis of Parkinson's disease (PD) and other related diseases. We have previously reported that ${\alpha}$-syn binds to the cell membranes in a transient and reversible manner. However, little is known about the physiologic function and/or consequence of this association. Here, we examined whether chemically induced perturbations to the cellular membranes enhance the binding of ${\alpha}$-syn, based on hypothesis that ${\alpha}$-syn may play a role in maintenance of membrane integrity or repair. We induced membrane perturbations or alterations in ${\alpha}$-syn-overexpressing human neuroblastoma cells (SH-SY5Y) by treating the cells with hydrogen peroxide ($H_2O_2$) or oleic acid. In addition, membranes fractionated from these cells were perturbed by treating them with proteinase K or chloroform. Dynamic interaction of ${\alpha}$-syn to the membranes was analyzed by the chemical cross-linking assay that we developed in the previous study. We found that membrane interaction of ${\alpha}$-syn was increased upon treatment with membrane-perturbing reagents in a dose and time dependent manner. These results suggest that perturbations in the cellular membranes cause increased binding of ${\alpha}$-syn, and this may have significant implication in the physiological function of ${\alpha}$-syn in cells.