• The Journal of Internal Korean Medicine
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• v.29 no.1
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• pp.189-199
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• 2008

Background & Objective : Jichul-hwan(JCH) has been used for the treatment of functional dyspepsia, regarded as a gastric dysmotility disease. We investigated the effects of JCH on gastric motility and its mechanisms of action in rats. Methods : The gastric wall was injured by tracting a part of stomach body in rats. Gastric emptying was measured after administration of normal saline(NS) or JCH in normal rats and gastric wall injured rats. To evaluate the mechanism of JCH under delayed gastric emptying conditions, normal rats were treated with atropine sulfate(1mg/kg, s.c.), quinpirole HCl(0.3mg/kgg, i.p.), $NAME(N^{G}-nitro-L-arginine$ methyl ester, 75mg/kg s.c.) and cisplatin(10mg/kg, i.p.). The gastric slow waves were measured for 30 minutes before and after administration of each solution(NS, JCH). Results : JCH 110.1mg/kg improved gastric emptying for 2 hrs(p=0.014). JCH 110.1mg/kg improved gastric emptying in the gastric wall injured rats(p=0.001). Under the delayed gastric emptying, JCH 110.1mg/kg improved gastric emptying in the group treated with atropine $sulfate(1.83{\pm}0.96$ vs $8.43{\pm}8.46$, p=0.003), but aggravated it with quinpirole $HCl(4.7{\pm}2.9$ vs $1.61{\pm}2.09$, p=0.021). Administration JCH 110.1mg/kg increased EGG power in rats. Conclusions : JCH stimulates gastric motility through the cholinergic pathway, so we expect that it would be effective in the treatment of dysmotility-like functional dyspepsia with low activity of vagus nerve.

• Journal of the Microelectronics and Packaging Society
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• v.19 no.1
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• pp.47-53
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• 2012

Bonding strength of Sn-3.0Ag-0.5Cu solder joint due to degradation characteristic of OSP surface finish was investigated, compared with SnPb finish. The thickness variation and degradation mechanism of organic solderability preservative(OSP) coating were also analyzed with the number of reflow process. To analyze the degradation degree of solder joint strength, FR-4 PCB coated with OSP and SnPb were experienced preheat treatment as a function of reflow number from 1st to 6th pass, respectively. After 2012 chip resistors were soldered with Sn-3.0Ag-0.5Cu on the pre-heated PCB, the shear strength of solder joints was measured. The thickness of OSP increased with increase of the number of reflow pass by thermal degradation during the reflow process. It was also observed that the preservation effect of OSP decreased due to OSP degradation which led Cu pad oxidation. The mean shear strength of solder joints formed on the Cu pads finished with OSP and SnPb were 58.1 N and 62.2 N, respectively, through the pre-heating of 6 times. Although OSP was degraded with reflow process, the feasibility of its application was proven.

• Progress in Medical Physics
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• v.14 no.1
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• pp.54-67
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• 2003

The voltage-dependence of N-type calcium current inactivation is U-shaped with the degree of inactivation roughly mirroring inward current. This voltage-dependence has been reported to result from a purely voltage-dependent mechanism. However, $Ca^{2＋}$-dependent inactivation of N-channels has also been reported. We have investigated the role of $Ca^{2＋}$ in N-channel inactivation by comparing the effects of $Ba^{2＋}$and $Ca^{2＋}$ on whole-cell N-current in rat superior cervical ganglion neurons. For individual cells in-activation was always larger in $Ca^{2＋}$ than in $Ba^{2＋}$ even when internal EGTA (11 mM) was replaced with BAPTA (20 mM). The inactivation vs. voltage relationship was U-shaped in both divalent cations. The enhancement of inactivation by $Ca^{2＋}$ was inversely related with the magnitude of inactivation in $Ba^{2＋}$ as if the mechanisms of inactivation were the same in both $Ba^{2＋}$ and $Ca^{2＋}$. In support of this idea we could separate fast ( ${\gamma}$ ～150 ms) and slow ( ${\gamma}$ ～ 2500 ms) components of inactivation in both $Ba^{2＋}$and $Ca^{2＋}$ using 5 sec voltage steps. Differential effects were observed on each component with $Ca^{2＋}$ enhancing the magnitude of the fast component and the speed of the slow component. The larger amplitude of fast component indicates that the more channels inactivate via this pathway with $Ca^{2＋}$ than with $Ba^{2＋}$, but the stable time constants support the idea the fast inactivation mechanism is identical in $Ba^{2＋}$and $Ca^{2＋}$. The results do not support a $Ca^{2＋}$-dependent mechanism for fast inactivation. However, the $Ca^{2＋}$-induced acceleration of the slowly inactivating component could result from a $Ca^{2＋}$-dependent process.

• Carbon letters
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• v.11 no.3
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• pp.224-234
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• 2010

Four activated carbons were produced by two-stage process as followings; semi-carbonization of indigenous biomass waste, i.e. cotton stalks, followed by chemical activation with KOH under various activation temperatures and chemical ratios of KOH to semi-carbonized cotton stalks (CCS). The surface area, total pore volume and average pore diameter were evaluated by $N_2$-adsorption at 77 K. The surface morphology and oxygen functional groups were determined by SEM and FTIR, respectively. Batch equilibrium and kinetic studies were carried out by using a basic dye, methylene blue as a probe molecule to evaluate the adsorption capacity and mechanism over the produced carbons. The obtained activated carbon (CCS-1K800) exhibited highly microporous structure with high surface area of 950 $m^2/g$, total pore volume of 0.423 $cm^3/g$ and average pore diameter of 17.8 ${\AA}$. The isotherm data fitted well to the Langmuir isotherm with monolayer adsorption capacity of 222 mg/g for CCS-1K800. The kinetic data obtained at different concentrations were analyzed using a pseudo-first-order, pseudo-second-order and intraparticle diffusion equations. The pseudo-second-order model fitted better for kinetic removal of MB dye. The results indicate that such laboratory carbons could be employed as low cost alternative to commercial carbons in wastewater treatment.

• Journal of Plant Biotechnology
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• v.7 no.1
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• pp.1-15
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• 2005

Salinity is one of the major limiting factors for agricultural productivity. In plants, accumulation of osmolytes plays a pivotal role in abiotic stress tolerance. Likewise, exclusion or compartmentation of $Na^+$ ions into vacuoles provides an efficient mechanism to avert deleterious effects of $Na^+$ in the cytosol. Both vacuolar and plasma membrane sodium transporters and $H^+-ATPases$ can provide the necessary ion homeostasis. A variety of crop plants were engineered with respect to the synthesis of osmoprotectants and ion-compartmentation, but there are other cellular pathways involved in the salinity responses that are still not completely explored. Genomics approaches are increasingly used to identify genes and pathway changes involved in salt-tolerance. The new knowledge may be used via guided genetic engineering of multiple genes to create crop plants with significantly increased productivity in saline soils. This review surveys how plants deal with high salt conditions and how salt tolerance can be improved by transgenic approaches.

• Progress in Superconductivity
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• v.1 no.2
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• pp.110-114
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• 2000

We have investigated the Josephson vortex dynamics in $Bi_2Sr_2CaCu_2O{8+\delta}$ intrinsic Josephson junctions subjected to a magnetic field parallel to $CuO_2$ planes. We investigated mesas with $40\times40{\mu}m^2$ in size and containing 6 and 20. intrinsic junctions. The zero field I-V characteristics exhibited a typical hysteretic, multi-branched nature of the intrinsic Josephson effect. At high magnetic fields (H>1.5 T), I-V characteristics showed flux flow steps. The Swihart velocity obtained from this observation was about $4.2\times10^5$ m/s, which was the lowest mode electromagnetic wave velocity of N coupled stack. The experimental I-V curves fitted well into the simple model of Cherenkov radiation including Ohmic and non-linear dissipation terms. This suggests that the dissipation mechanism of Josephson vortex be due to both Cherenkov radiation and quasiparticle tunneling current.

• Bulletin of the Society of Naval Architects of Korea
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• v.26 no.1
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• pp.1-10
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• 1989

When a ship is travelling in following seas, the encounter frequency is reduced to be very low. n that case surf-riding, broaching-to and capsizing phenomena are most likely to occur. In the present paper, the emphasis is laid upon the transverse stability of ships in following seas, which is related to capsizing phenomenon. The authors intend to clarify the mechanism of the stability variation in following seas. In order to predict that variation, the theoretical calculation method and computer programming are developed. The theoretical calculation is based on Froude-Krylov Hypothesis and static equilibrium condition in waves. Through the application of present calculation method to cargo vessel and fishing boat, it is verified that the transverse stability in following seas with crest amidships can be reduced to a half extent in comparison with calm water stability. On the other hand, the present calculation results are compared with existing experimental data.

• YAKHAK HOEJI
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• v.55 no.6
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• pp.485-491
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• 2011

Previously, we have reported that apigenin, a natural flavonoid found in a variety of vegetables and fruits, stimulated melanogenesis through the activation of $K^+-Cl^-$-cotransport (KCC) in B16 melanoma cells. In this study we investigated the possible involvement of reactive oxygen species (ROS) in the mechanism of apigenin-induced melanogenesis in B16 cells. Apigenin elevated intracellular ROS level in a dose-dependent manner. Treatment with various inhibitors of NADPH oxidase, diphenylene iodonium (DPI), apocynin (Apo) and neopterine (NP) significantly inhibited both the generation of ROS and melanogenesis induced by apigenin. In addition these inhibitors profoundly inhibited apigenin-induced $Cl^-$-dependent $K^+$ efflux, a hallmark of KCC activity. However, the apigenin-induced ROS generation was not significantly affected by treatment with a specific KCC inhibitor R-(+)-[(2-n-butyl-6,7-dichloro-2-cyclopentyl-2,3-dihydro-1-oxo-1H-inden-5-yl)oxy]acetic acid (DIOA). These results indicate that the ROS production may be a upstream regulator of the apigenin-induced KCC stimulation, and in turn, melanogenesis in the B16 cells. Taken together, these results suggest that the NADPH oxidase-mediated ROS production may play an important role in the apigenin-induced melanogenesis in B16 cells. These results further suggest that NADPH oxidase may be a good target for the management of hyperpigmentation disorders.

• YAKHAK HOEJI
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• v.52 no.6
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• pp.500-506
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• 2008

Apigenin, a natural flavonoid found in a variety of vegetables and fruits, has been shown to possess many biological functions. In this study we found that apigenin stimulated melanin synthesis in a dose-dependent manner in B16 murine melanoma cells. Since in our previous study $K^+$-$Cl^-$-cotransport (KCC) has been shown to mediate the mechanism of action of apigenin in neuronal cells, we further investigated the role of KCC in the melanogenesis-stimulating effect of apigenin in B16 cells. At nontoxic concentrations apigenin induced $Cl^-$-dependent $K^+$ efflux, a hallmark of KCC activity, which was markedly prevented by a specific KCC inhibitor R-(+)-[(2-n-butyl-6,7-dichloro-2-cyclopentyl-2,3-dihydro-1-oxo-1H-inden-5-yl)oxy]acetic acid (DIOA). These results indicate that KCC is functionally present, and activated by apigenin in the B16 cells. In addition, the apigenin-induced stimulation of melanogenesis was also significantly inhibited by DIOA. NEthylmaleimide (NEM), a known KCC activator, induced $Cl^-$ efflux and stimulated melanogenesis in a concentration-dependent fashion. Both effects of NEM were significantly inhibited by DIOA. Taken together, these results suggest that apigenin can modulate melanogenesis through the activation of a membrane ion transporter, KCC in B16 cells. These results further suggest that apigenin may be a good candidate in the therapeutic strategy for hypopigmentation disorders, such as vitiligo.

• Genomics & Informatics
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• v.19 no.1
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• pp.7.1-7.13
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• 2021

Levodopa (L-DOPA) therapy is normally practised to treat motor pattern associated with Parkinson disease (PD). Additionally, several inhibitory drugs such as Entacapone and Opicapone are also cosupplemented to protect peripheral inactivation of exogenous L-DOPA (~80%) that occurs due to metabolic activity of the enzyme catechol-O-methyltransferase (COMT). Although, both Entacapone and Opicapone have U.S. Food and Drug Administration approval but regular use of these drugs is associated with high risk of side effects. Thus, authors have focused on in silico discovery of phytochemicals and evaluation of their effectiveness against human soluble COMT using virtual screening, molecular docking, drug-like property prediction, generation of pharmacophoric property, and molecular dynamics simulation. Overall, study proposed, nine phytochemicals (withaphysalin D, withaphysalin N, withaferin A, withacnistin, withaphysalin C, withaphysalin O, withanolide B, withasomnine, and withaphysalin F) of plant Withania somnifera have strong binding efficiency against human COMT in comparison to both of the drugs i.e., Opicapone and Entacapone, thus may be used as putative bioenhancer in L-DOPA therapy. The present study needs further experimental validation to be used as an adjuvant in PD treatment.