• 대한화학회지
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• 제34권6호
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• pp.561-568
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• 1990

수용액에서 가벼운 란탄족 금속이온의 전기화학적 거동을 직류 폴라로그래피, 펄스차이 폴라로그래피 및 순환 전압전류법으로 연구하였다. La$^{3+}$, Pr$^{3+}$ 및 Nd$^{3+}$의 환원은 0.1 M LiCl 지지전해질에서 3전자가 관여하는 비가역적인 반응이었다. Sm$^{3+}$의 환원은 0.1 M TMAI 지지전해질에서 1전자에 이어 2전자가 관여하는 비가역적인 반응이었으며, Eu$^{3+}$의 환원은 0.1 M LiCl 지지전해질에서 1전자에 이어 2전자가 관여하는 유사가역반응 및 비가역반응이었다. 펄스차이 폴라로그래피에 의하면 pH 4 이하에서는 수소이온의 촉매효과에 의하여 가수분해된 란탄족 금속이온 (Ln(OH)$^{2+}$)은 란탄족 금속이온(Ln$^{3+}$)보다 양전위에서 환원되었으며, 봉우리 전류의 크기는 Eu$^{3+}$ < Sm$^{3+}$ < Nd$^{3+}$ < Pr$^{3+}$ < La$^{3+}$ 순으로 증가하였다. 순환 전압전류법에서 주사속도 변화에 대한 전류함수의 크기는 [H$^{+}$]/[Ln$^{3+}$]의 비에 의존하였으며, pH 및 란탄족 금속이온의 농도가 낮을수록 수소이온에 의한 반응 또는 촉매전류가 증가하였다.

• The Korean Journal of Physiology and Pharmacology
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• 제20권5호
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• pp.507-514
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• 2016

Although 3D-complex fractionated atrial electrogram (CFAE) mapping is useful in radiofrequency catheter ablation for persistent atrial fibrillation (AF), the directions and configuration of the bipolar electrodes may affect the electrogram. This study aimed to compare the spatial reproducibility of CFAE by changing the catheter orientations and electrode distance in an in -silico left atrium (LA). We conducted this study by importing the heart CT image of a patient with AF into a 3D-homogeneous human LA model. Electrogram morphology, CFAE-cycle lengths (CLs) were compared for 16 different orientations of a virtual bipolar conventional catheter (conv-cath: size 3.5 mm, inter-electrode distance 4.75 mm). Additionally, the spatial correlations of CFAE-CLs and the percentage of consistent sites with CFAE-CL<120 ms were analyzed. The results from the conv-cath were compared with that obtained using a mini catheter (mini-cath: size 1 mm, inter-electrode distance 2.5 mm). Depending on the catheter orientation, the electrogram morphology and CFAE-CLs varied (conv-cath: $11.5{\pm}0.7%$ variation, mini-cath: $7.1{\pm}1.2%$ variation), however the mini-cath produced less variation of CFAE-CL than conv-cath (p<0.001). There were moderate spatial correlations among CFAE-CL measured at 16 orientations (conv-cath: $r=0.3055{\pm}0.2194$ vs. mini-cath: $0.6074{\pm}0.0733$, p<0.001). Additionally, the ratio of consistent CFAE sites was higher for mini catheter than conventional one ($38.3{\pm}4.6%$ vs. $22.3{\pm}1.4%$, p<0.05). Electrograms and CFAE distribution are affected by catheter orientation and electrode configuration in the in-silico LA model. However, there was moderate spatial consistency of CFAE areas, and narrowly spaced bipolar catheters were less influenced by catheter direction than conventional catheters.

• 콘크리트학회논문집
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• 제16권4호
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• pp.549-555
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• 2004

Cement of three alkalinities (equivalent alkalinities of 0.36,0.52 and 0.97) was employed in fabricating a set of classical G109 type specimens. To-date, these have been subjected to a one week wet-one week dry cyclic pending using 15 w/o NaCl solution. At the end of the dry period, potential and macro-cell current were measured to indicate whether the top reinforcing steel was in the passive or active state. Once this bar became active, the specimen was autopsied and the extent of corrosion was documented. Subsequent to visual inspection, concrete powder samples were collected from the upper region of the top rebar trace; and at a certain times concrete cores were taken from non-reinforced specimens. Using these, determinations were made of (1) critical chloride concentration for corrosion initiation ($Cl_{th}^-$), (2) effective chloride diffusion coefficient ($D_e$), and (3) pore water alkalinity ($[OH^-]$). The pore water alkalinity was strongly related to the alkali content of cement that was used in the mix. The chloride concentration, ($Cl^-$), was greater at active than at passive sites, presumably as a consequence of electro migration and accumulation of these species at active site subsequent to corrosion initiation. Accordingly, ($Cl^-$) at passive sites was considered indicative of the threshold concentration fur corrosion initiation. The $Cl_{th}^-$ was increased with increasing Time-to-corrosion ($T_i$). Consequently, the HA(High Alkalinity) specimens exhibited the highest $Cl_{th}^-$ and the NA(Normal Alkalinity) was the least. This range exceeds what has previously been reported in North America. In addition, the effective diffusion coefficient, $D_e$, was about 40 percent lower for concrete prepared with the HA cement compared to the NA and LA(Low Alkalinity) ones.

• Journal of Nutrition and Health
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• 제30권4호
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• pp.442-450
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• 1997

Conjugated dienoic derivatives of linoleic acid(CLA) are a mixture of positional and geometric isomers of linoleic acid(LA). We previously found that CLA changes the fatty acid profile in chicken eggs and serum by decreasing monounsaturated fatty acids. Studies were conducted to explore the effects of CLA on fatty acid composition. Rabbits were fed a semisynthetic diet with or without CLA(0.5g CLA/rabbit/day) for 22 weeks. Compared to the control, rabbits fed CLA had significantly lower monounsaturated fatty acid levels(palmitoleic acid Cl6 : 1 by 50% and oleic acid Cl8 : 1, by 20%) in plasma lipids. We found similar differences in fatty acid composition in the liver and the aorta. The inhibitory effect of CLA on $\Delta$9 desaturation was confirmed in a human hepatoma cell line, Hep G2. CLA significantly decreased $\Delta$9 desaturation in 4-5 hours as shown by an increase in the ratio of Cl6 : 0 to C 16 1, This is apparently due to a decrease in $\Delta$9 desaturase(stearoyl-CoA desaturase, SCD) activity ; it was decreased more than 50%. These results, along with our previous findings, indicate that CLA is an inhibitor of $\Delta$9 desaturase in the liver.

• 한국전기전자재료학회논문지
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• 제17권9호
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• pp.930-935
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• 2004

$({Li}_{0.5}0{La}_{0.5}){TiO}_3$ (LLTO) solid electrolyte was grown on LiCo{O}_2 (LCO) cathode films deposited on $Pt/Ti{O}-2/Si{O}_2/Si$ substrate using pulsed laser deposition for all-solid-state lithium microbattery. LLTO solid electrolyte exhibits an amorphous phase at various deposition temperatures. LLTO films deposited at 10$0^{\circ}C$ showed a clear interrace without any chemical reaction with LCO, and showed an initial discharge capacity of 50 $\mu$Ah/cm$^2$-$\mu$m and capacity retention of 90 % after 100 cycles with Li anode in 1mol$ LiCl{O}_4$ in propylene carbonate (PC). The increase of capacity retention in LLTO/LCO structure than LCO itself was attributed to the structural stability of LCO cathode films by the stacked LLTO. The cells of LLTO/LCO with LLTO grown at $100^{\circ}C$ showed a good cyclic property of 63.6 % after 300 cycles. An amorphous LLTO solid electrolyte is possible for application to solid electrolyte for all-solid-state lithium microbattery.

• Asian-Australasian Journal of Animal Sciences
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• 제19권1호
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• pp.119-125
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• 2006

The present study including two experiments was designed to determine the effect of media containing different rare earth elements (REE) on proliferation and fatty acids accumulation in 3T3-L1 cell cultures. In Experiment 1, 3T3-L1 preadipocytes in 96-well plates ($1.5{\times}10^4cells/ml$) were cultured with Dulbecco's modified Eagle's medium (DMEM) containing 10% fetal bovine serum (FBS) for 24 h. Then the media were changed to the following 10 different media for 48 h: DMEM containing 10% FBS for the control; the above media containing $5{\mu}M$, $10{\mu}M$ or $15{\mu}M$ of $LaCl_3$, $CeCl_3$ or the mixture of these REE chlorides. The proliferation rate of the cells was measured and compared by a non-isotope method-XTT method. In Experiment 2 the cells in 24-well plates ($1.5{\times}10^4cells/ml$) were cultured in DMEM containing 10% FBS for 7 days until confluent and then were changed to above DMEM containing dexamethasone, methyl-isobutylxanthine and insulin (DMI) for two days. Afterwards the media were changed to the 10 different media with REE supplements as in Experiment 1 and cultured for 6 days. The cells were then harvested for fatty acids analysis by gas chromatography. It was found that supplementation of La (5, 10 and $15{\mu}M$), Ce ($5{\mu}M$ and $15{\mu}M$) and the mixture REE (5, 10 and $15{\mu}M$) stimulated (p<0.05) the proliferation of 3T3-L1 preadipocytes (Experiment 1). In the differentiating 3T3-L1 cells supplementation of La ($5{\mu}M$ and $10{\mu}M$), Ce ($5{\mu}M$) and the mixture REE ($5{\mu}M$ and $15{\mu}M$) decreased (p<0.05) the concentration of monounsaturated fatty acids (MUFA) per $10^5cells$, while the supplementation of La ($5{\mu}M$), Ce ($5{\mu}M$) and the mixture REE ($15{\mu}M$) increased (p<0.05) the ratio of saturated fatty acids (SFA) to MUFA. These results indicate that the supplementation of REE to the media may affect proliferation, differentiation and lipogenesis rates of 3T3-L1 cells. However, the effect may depend upon the level or type of REE applied.

• Carbon letters
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• 제8권2호
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• pp.95-100
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• 2007

A series of activated carbons (ACs) were derived from sugarcane bagasse under two activation schemes: steam-pyrolysis at $600-800^{\circ}C$ and chemical activation with $H_3PO_4$ at $500^{\circ}C$. Some carbons were treated at 400, $600^{\circ}C$, or for 1-3 h, and/or in flowing air during pyrolysis of acid-impregnated mass. XRD profiles displayed two broad diffuse bands centered around $2{\theta}=23$ and $43^{\circ}$, currently associated with diffraction from the 002 and 100/101 set of planes in graphite, respectively. These correspond to the interlayer spacing, Lc, and microcrystallite lateral dimensions, La, of the turbostratic (fully disordered) graphene layers. Steam pyrolysis-activated carbons exhibit only the two mentioned broad bands with enhancement in number of layers, with temperature, and small decrease in microcrystallite diameter, La. XRD patterns of $H_3PO_4$-ACs display more developed and separated peaks in the early region with maxima at $2{\theta}=23$, 26 and $29^{\circ}$, possibly ascribed to fragmented microcrystallites (or partially organized structures). Diffraction within the $2{\theta}=43^{\circ}$ is still broad although depressed and diffuse, suggesting that the intragraphitic layers are less developed. Varying the conditions of chemical activation inflicts insignificant structural alterations. Circulating air during pyrolysis leads to enhancement of the basic graphitic structure with destruction and degradation in the lateral dimensions.

• 한국지역지리학회지
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• 제19권4호
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• pp.627-640
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• 2013

본 연구는 전남 여수시 백도의 지형형성과정을 분석하는 데 목적이 있다. 백도는 다도해의 형성과정과 해안지형을 이해하는 데 중요한 단서가 되는 섬이다. 백도를 구성하고 있는 암석은 미문상 화강암으로서 약 6천만 년 전에 형성된 것이다. 현재의 백도 지형을 형성케 한 요인은 지구조운동에 의한 북동-남서 방향과 동북동-서남서 방향의 절리선과 지반의 융기 그리고 파랑에 의한 침식작용 때문이다. 또한 백도를 구성하는 미문상 화강암에 대한 지화학적 분석에 의하면 백도는 칼크알칼리 계열(Calc-Alkaline)의 마그마 분화 특징을 보이며, 화산호 화강암(VAG)에 속한다. 즉 대륙주변부의 섭입환경에서 생성된 마그마임을 의미한다. 또한 단층과 해안단구로 보이는 지형이 관찰되나 백도일원에 신생대 제4기 후빙기 때 해수면 상승보다 더 큰 융기운동이 있었는지에 대해 추후 논의가 필요하다.

• Archives of Pharmacal Research
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• 제19권1호
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• pp.62-65
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• 1996

A homologous series of twenty, hitherto unreported, analogues of 5-halosubstituted $1, 3-Bis(\omega-cyanoalkyl)uracil$acyclic nucleosides were synthesized by the series of alkylation reactions of 5-halouracils with the corresponding chloroacetonitrile, chloropropionitrile, chlorobutyronitrile and 5-chlorovaleronitrile $(Cl-(C_ 2)_n-CN: n=l, 2, 3, 4)\; in\; anhydrous\; DMSO\; (or DMF)/K_2CO_3(or NaH)\; under\; 75^{\circ}C$ temperature. Antitumor activities for the synthesized compounds were determined against three cell lines (FM-3A cell, P-388 cell and U-938 cell lines). The compounds that exhibited moderate activity to significant activity, included la-b, 2a-b, 3a-c, and 4a, whose compounds were active against P-388, FM-3A and U-937 cell lines with the compounds la, lb, and 2a, showing significant antitumor activity (inhibitory concentrations $(IC_{50})$ ranged from 2.2 to $7.0\mug/ml$). Their strucrure-activity relationship did not show any activity differences in their effective chain length (methyl, ethyl, propyl, butyl) in 1, 3-bis(.omega.-cyanoalkyl) uracils.

• Macromolecular Research
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• 제15권3호
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• pp.221-224
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• 2007

A silica-magnesium bisupport (SMB) was prepared by a sol-gel method for use as a support for a metal-locene/Ziegler-Natta hybrid catalyst. The prepared $rac-Et(Ind)_2ZrCl_2/TiCl_4$/MAO(methylaluminoxane)/SMB catalyst was applied to the copolymerization of ethylene with l-hexene using a variable triethylaluminum (TEA)/transition-metal (Ti) ratio and fixed MAO/transition-metal (Zr) ratio. The effect of the Al(TEA)/Ti ratio on the physical properties and chemical composition distributions (CCDs) of the ethylene-hexene copolymers produced by the hybrid catalyst was investigated. In the ethylene-hexene copolymers, two melting temperatures attributed to the metal-locene and Ziegler-Natta catalysts were clearly observed. The number of CCD peaks was increased from six to seven and the temperature region in which the peaks for the short chain branches of the ethylene-hexene copolymer were distributed became lower as the Al(TEA)/Ti ratio was increased from 300 to 400. Furthermore, the temperature regions corresponding to the lamellas in the copolymer became lower and those corresponding to the small lamellas in the copolymer became higher as the Al(TEA)/Ti ratio was increased from 300 to 400. In the copolymer produced with Al(TEA)/Ti = 500, however, only four CCD peaks were observed and the short chain branches were poorly distributed.