• Archives of Pharmacal Research
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• 제29권7호
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• pp.605-616
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• 2006

A wide variety of drugs and endogenous bioactive amines are organic cations (OCs). Approximately 40% of all conventional drugs on the market are OCs. Thus, the transport of xenobiotics or endogenous OCs in the body has been a subject of considerable interest, since the discovery and cloning of a family of OC transporters, referred to as organic cation transporter (OCTs), and a new subfamily of OCTs, OCTNs, leading to the functional characterization of these transporters in various systems including oocytes and some cell lines. Organic cation transporters are critical in drug absorption, targeting, and disposition of a drug. In this review, the recent advances in the characterization of organic cation transporters and their distribution in the small intestine are discussed. The results of the in vitro transport studies of various OCs in the small intestine using techniques such as isolated brush-border membrane vesicles, Ussing chamber systems and Caco-2 cells are discussed, and in vivo knock-out animal studies are summarized. Such information is essential for predicting pharmacokinetics and pharmacodynamics and in the design and development of new cationic drugs. An understanding of the mechanisms that control the intestinal transport of OCs will clearly aid achieving desirable clinical outcomes.

• 한국자원식물학회지
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• 제34권6호
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• pp.566-574
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• 2021

This research was carried out to investigate the correlation between soil chemical properties and bioactive compounds of Acer tegmentosum Maxim. The methods of determining bioactive compounds were determined by high performance liquid chromatography, that contained (-)-gallocatechin (0.04±0.01 ~ 0.43±0.28%), salidroside (0.90±0.06 ~ 3.86±0.59%), tyrosol (0.03±0.00 ~ 0.43±0.00%), (-)-catechin (0.05±0.01 ~ 0.37±0.14%), 6'-O-galloylsalidroside (0.02± 0.01 ~ 0.31±0.06%), (-)-epicatechin-gallate (0.01±0.00 ~ 0.04±0.01%). The soil chemical properties analysis such as soil pH, electric conductivity (EC), organic matter (OM), total nitrogen (TN), available phosphate (Avail. P₂O₅), exchangeable cation and cation exchange capacity (CEC) were performed following the standard manual. The correlation analysis between soil chemical properties and bioactive compounds of A. tegmentosum, soil pH, available phosphate and exchangeable cation (Ca²⁺ and Mg²⁺) were negatively correlated with content of salidroside. On the other hand, soil exchangeable cation (Na⁺) showed positive correlation with content of salidroside. The results of this study was able to investigate the correlation between soil chemical properties and bioactive compounds of A. tegmentosum.

• 한국결정성장학회지
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• 제9권6호
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• pp.601-605
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• 1999

$LiCoO_2$와 고용체 화합물인 $LiCo_{1-x}Ni_XO_2$을 고상반응법을 이용하여 제조하여 XRD, SEM, 입도분석, $^7$Li NMR을 통하여 그 구조적 cation mixing 현상을 조사하였다. 고상반응법으로 합성한 $LiCoO_2$와 $LiCo_{1-x}$$Ni_x$$O_2$의 미세결정상은 hexagonal layered structure를 보여주었고 전반적인 입도는 니켈의 함량에 따라 증가되었다. 고용체에 있어서 Ni의 함량 분율(x)이 x=0.3, 0.5, 0.7로 Ni의 양이 증가함에 따라 cation mixing 효과가 증가되었다. $^7$Li NMR의 peak frequency는 Ni의 함량이 증가함에 따라 high frequency로 shift되었고 line width는 Ni의 함량에 따라 넓어지는 양상을 보여주었다.

• Bulletin of the Korean Chemical Society
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• 제23권2호
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• pp.337-345
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• 2002

The equilibrium structures for the ground and transition states of $C_7H_7^+$ isomers have been investigated using sophisticated ab initio quantum mechanical techniques with various basis sets. The structures of tropyrium and benzyl cations have been fully optimized at the DZP CCSD(T) levels of theory. And the structures of o-, m-and p-tolyl cations are optimized fully up to the DZ CCSD(T) levels of theory. The geometries for the transition states between three isomers of tolyl cations have been optimized up to DZP CISD level of theory. The SCF harmonic vibrational frequencies for tropylium, benzyl, and three isomers of tolyl cations are all real numbers, which confirm the potential minima and each unique imaginary vibrational frequencies for TS1 and TS2 confirm the true transition states. The relative energy of the benzyl cation with respect to the tropyrium cation is predicted to be 28.5 kJ/mol and is in good agreement with the previous theoretical predictions. The 0 K heats of formation, ${\Delta}H^{\circ}_{f0}$, have been predicted to be 890, 1095, 1101, and 1110 kJ/mol for tropylium, ortho-, meta-, and para-tolyl cations by taking the experimental value of 919 kJ/mol for the benzyl cation as the base level. The relative stability between tolyl cations is in the order of ortho

• 한국연초학회지
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• 제30권2호
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• pp.109-116
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• 2008

Mutagenicity of cigarette smoke is one of the major health concerns related to smoking. Reduction of the components comprising mutagenic activity in cigarette mainstream smoke can be expected to bring about reduced risk of smoking. The purpose of this study is to isolate mutagenic compounds and to investigate the relative contribution to allover mutagenicity of smoke to find clues for the effective elimination of the components. Cigarette smoke condensate (CSC) was obtained from total particulate matter (TPM) of mainstream smoke, and several fractions fractionated from CSC were made by combination of cation exchange chromatograph and reverse-phase chromatography. The mutagenic activity of these fractions was assessed using Salmonella mutagenicity assay with S. typimurium TA98 strain in the presence of metabolic activation system (S-9). The fractions isolated by cation exchange and reverse-phase column showed relatively high mutagenic activity. The basic and hydrophilic fraction 9 showed approximately 33% of mutagenic activity of CSC and its specific activity was 2,459 revertants/mg TPM. These results suggest that hydrophilic cation exchanger and/or other adsorbents possessing similar properties may be used to remove the mutagenic compounds from mainstream smoke.

• 한국응용과학기술학회지
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• 제22권3호
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• pp.219-227
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• 2005

Competitive solvent extraction of the mixure of alkali metal and alkaline earth cation from water into organic solvent containing the crown ether carboxylic acid and anlogous crown ether phosphonic acid was investigated as follows. The lipophilic group is found to strongly influence to the selective extraction in the mixed systems from only alkali metal cation for sym-(n-decyldibenzo)-16-crown-5-oxyacetic acid $\underline{1}$ to mostly alkaline earth metal cation for sym-bis[4(5)-tert-butylbenzo]-16-crown-5-oxyacetic acid $\underline{3}$. Monoethyl sym-(n-decyldibenzo)-16-crown-5-oxymethylphosphonic acid $\underline{2}$. and monoethyl-sym- bis]4(5)-tert-butylbenzo]-16-crown-5-oxymethylphosphonic acid $\underline{4}$ showed good selectivity for $Na^+$ over $Mg^{2+}$, the second extracted ion. Structural variation in the crown ether phosphonic acid somewhat was influenced to the extraction selectivity in the mixed systems. when variation of the ionized group is influenced in the mixed systems, the selectivity of $Na^+$ as the second extracted ion was much better crown ether carboxylic acid $\underline{1}$ than crown ether phosphonic acid $\underline{2}$, while the efficiency of $Na^+$ extraction was better $\underline{2}$ (83% total loading) than $\underline{1}$ (32%).

• The Korean Journal of Physiology and Pharmacology
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• 제9권2호
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• pp.69-75
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• 2005

TRPM7, a cation channel protein permeable to various metal ions such as $Mg^{2+}$, is ubiquitously expressed in variety of cells including lymphocytes. The activity of TRPM7 is tightly regulated by intracellular $Mg^{2+}$, thus named $Mg^{2+}$-inhibited cation (MIC) current, and its expression is known to be critical for the viability and proliferation of B lymphocytes. In this study, the level of MIC current was compared between immature (WEHI-231) and mature (Bal-17) B lymphocytes. In both cell types, an intracellular dialysis with $Mg^{2+}$-free solution (140 mM CsCl) induced an outwardly-rectifying MIC current. The peak amplitude of MIC current and the permeability to divalent cation ($Mn^{2+}$) were several fold higher in Bal-17 than WEHI-231. Also, the level of mRNAs for TRPM7, a molecular correspondence of the MIC channel, was significantly higher in Bal-17 cells. The amplitude of MIC was further increased, and the relation between current and voltage became linear under divalent cation-free conditions, demonstrating typical properties of the TRPM7. The stimulation of B cell receptors (BCR) by ligation with antibodies did not change the amplitude of MIC current. Also, increase of extracellular $[Mg^{2+}]_c$ to enhance the $Mg^{2+}$ influx did not affect the BCR ligation-induced death of WEHI-231 cells. Although the level of TRPM7 was not directly related with the cell death of immature B cells, the remarkable difference of TRPM7 might indicate a fundamental change in the permeability to divalent cations during the development of B cells.

• Korean Chemical Engineering Research
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• 제56권3호
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• pp.361-369
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• 2018

A manufacturing method has been devised to prepare novel heterogeneous cation exchange membranes by mixing ethylene vinyl acetate (EVA) copolymers with a commercial cation exchange resin. Optimum material characteristics, mixture ratios and manufacturing conditions have been worked out for achieving favorable membrane performance. Ion exchange capacity, electrical resistance, water uptake, swelling ratio and tensile strength properties were measured. SEM analysis was used to monitor morphology. Effects of vinyl acetate (VA) content, melt index (MI) and ion exchange resin content on properties of heterogeneous cation exchange membranes have been discussed. An application test was carried out by mounting a selected membrane in a membrane capacitive deionization (MCDI) system to investigate its desalination capability. 0.92 meq/g of ion exchange capacity, $8.7{\Omega}.cm^2$ of electrical resistance, $40kgf/cm^2$ of tensile strength, 19% of swelling ratio, 42% of water uptake, and 56.4% salt removal rate were achieved at best. VA content plays a leading role on the extent of physical properties and performance; however, MI is important for having uniform distribution of resin grains and achieving better ionic conductivity. Overall, manufacturing cost has been suppressed to 5-10% of that of homogeneous ion exchange membranes.

• Bulletin of the Korean Chemical Society
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• 제35권12호
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• pp.3495-3501
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• 2014

A novel crystal, the mono-protonated metformin acetate (1), was obtained and characterized by elemental analysis, IR spectroscopy and X-ray crystallography. It was found that one of the imino group in the metformin cation was protonated along with the proton transfer from the secondary amino group to the other imino group. Its crystal structure was then compared with the previously reported diprotonated metformin oxalate (2). The difference between them is that the mono-protonated metformin cations can be linked by hydrogen bonding to form dimers while the diprotonated metformin cations cannot. Both of them are stabilized by intermolecular hydrogen bonds to assemble a 3-D supermolecular structure. The four potential tautomer of the mono-protonated metformin cation (tautomers 1a, 1b, 1c and 1d) were optimized and their single point energies were calculated by Density Functional Theory (DFT) B3LYP method based on the Polarized Continuum Model (PCM) in water, which shows that the most likely existed tautomer in human cells is the same in the crystal structure. Based on the optimized structure, their Wiberg bond orders, Natural Population Analysis (NPA) atomic charges, molecular electrostatic potential (MEP) maps were calculated to analyze their electronic structures, which were then compared with the corresponding values of the diprotonated metformin cation (cation 2) and the neutral metformin (compound 3). Finally, the possible tautomeric mechanism of the mono-protonated metformin cation was discussed based on the observed phenomena.

• 대한화학회지
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• 제36권1호
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• pp.137-146
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• 1992

양이온 교환된 천연 제올라이트 $K_{111}$의 CO 기체 흡착특성과 양이온효과를 연구하였다. $Na^+-,\;Cu^{2+}-\;및\;Ba^{2+}-\;K_{111}$ 의 경우 우수한 CO 흡착능을 가졌으며, 0.4N $BaCl_2$ 수용액으로 처리된 것이 가장 큰 CO 흡착능을 나타내었고, 합성 제올라이트 4A, 5A보다 뛰어난 흡착능을 가짐을 알 수 있었다. 양이온의 종류에 따른 흡착경향은 $Ba^{2+}>Cu^{2+}>Na^+>K^+>Mg^{2+}>Ca^{2+}$ 의 순서로 나타났으며 단위격자당 교환된 양이온의 수와 종류 그리고 세공의 크기 등이 CO 기체의 흡착에 있어 주요 인자로 작용함을 알 수 있었다. 그리고 K111의 양이온에 따른 흡착경향을 비교하기 위해서 CNDO/2 계산을 행하였다. 계산된 결과 8원환 모델 내의 양이온과 CO 기체와의 상호작용 에너지는 실험결과와 비슷한 경향임을 알 수 있었다.