• Journal of Applied Biological Chemistry
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• 제61권4호
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• pp.397-403
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• 2018

조팝나무(Spiraea prunifolia) 잎을 80% MeOH 수용액으로 추출한 뒤, 감압 농축한 추출물을 EtOAc, n-BuOH과 $H_2O$층으로 계통 분획을 실시하였다. n-BuOH분획에 대하여 $SiO_2$, ODS column chromatograph 및 중압분취 장비를 반복실시하여 2종의 phenolic glucoside화합물을 분리 및 정제하였다. NMR 및 Mass데이터를 해석하여, isosalicin (1)와 crenatin (2)로 구조 동정 하였다. 분리한 2종의 화합물에 대하여 UPLC-MS/MS 질량 분석기를 기반으로 다중반응검지 (MRM mode) 분석법을 이용하여 정량분석 하였다. 그 결과, crenatin은 9.53 mg/g 및 isosalicin은 0.65 mg/g이 조팝나무 잎 추출물에 함유된 것을 확인하였다. 조팝나무 잎에서 분리된 화합물이 $H_2O_2$에 의해 유발된 산화스트레스로부터 신경세포 보호효과를 검증한 결과, 신경모세포종인 SK-N-MC 세포에 대해서 화합물 1 및 2 (100 mM) 모두 세포 독성은 보이지 않았으며, 특히 화합물 2 (crenatin)는 $H_2O_2$처리에 따른 신경세포의 외형적 변화, 세포 손상, 세포 사멸을 억제하여 산화스트레스로부터 신경세포를 보호하는 효과가 있음을 확인하였다.

• 분석과학
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• 제18권2호
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• pp.163-167
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• 2005

본 연구에서는 ESI/MS/MS를 이용하여 혈장에서 카르니틴을 신속하게 정량하는 분석방법을 개발하였다. 분석방법은 free carnitine (FC)는 유도체화 없이 혈액여지를 80% 메탄올로 추출하여 분석하였고, Total carnitine (TC)은 가수분해 한 후 추출하여 multiple reaction monitoring (MRM) scan mode로 분석하였다. Acyl carnitine (AC)는 TC에서 FC를 뺀 값을 사용하였다. 카르니틴의 분석에서 상관계수 ($r^2$)는 0.9995, 회수율은 97%, 재현성은 변동계수가 10% 이하, 검출한계는 $0.0016{\mu}mol/L$ 였다. 이 방법은 기존의 액체 크로마토그래피 보다 전처리가 간다하고 짧은 분석시간과 좋은 감도와 재현성을 보여 주었다. 정상인은 AC가 낮고 FC는 높은 패턴을 보였고, 유전성대사질환 환자는 FC는 낮고 AC가 높은 패턴으로 나타나 카르니틴의 3분획 분석은 유전성대사질환 환자의 확진 및 모니터링에 유용함을 보여주었다.

• Environmental Engineering Research
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• 제11권5호
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• pp.285-291
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• 2006

Biofiltration is a simple, effective, economically viable and the most widely used gas treatment technique for treating malodors at low concentrations and high flow rates. This paper reports the performance of two lab scale immobilized cell biofilters operated in continuous mode for hydrogen sulfide ($H_2S$) and ammonia ($NH_3$) removal. The removal efficiency (RE, %) and the elimination capacity (EC, $g/m^3{\cdot}hr$) profiles were monitored by subjecting the biofilters to different loading rates of $H_2S$ (0.3 to $8\;g/m^3{\cdot}hr$) and $NH_3$ (0.3 to $4.5\;g/m^3{\cdot}hr$). The removal efficiencies were greater than 99% when inlet loading rate to the biofilters were upto $6\;gH_2S/m^3{\cdot}hr$ and $4\;gNH_3/m^3{\cdot}hr$ respectively. The performance of the biofilters were also ascertained by conducting shock loading studies at a loading rate of $10\;gH_2S/m^3{\cdot}hr$ and $6\;gNH_3/m^3{\cdot}hr$. The results from this study show high removal efficiency, good recuperating potential and stability of the immobilized microbial consortia to transient shock loads.

• 한국결정학회지
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• 제11권1호
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• pp.22-27
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• 2000

The structure of cis-(malonato)[(4R,5R)-4,5-bis(aminomethyl)-2-isopropyl-1,3-dioxolane]platinum(II) with a potent anticancer activity has been determined by the X-ray crystallographic method. Crystal data are as follows: Pt(C/sub 11/H/sub 20/N₂O/sub 6/), M/sub 4/=471.38, monoclinic, P2₁, a=7.112(1), b=33.615(3), c=7.135(1)Å, β=116.80(1)°, V=1522.6(3)Å, and Z=4. The two independent molecules with very similar structures are approximately related by pseudo two-fold screw axis symmetry, which makes the monolinic cell look like the orthorhombic cell with one molecule in the asymmetric unit and space group C222₁. The crystal packing mode is similar to that of the analogue with the dimethyl substituents instead of the isopropyl group. The Pt atom is coordinate to two O and two N atoms in a square planar structure. The six-membered chelate ring in the leaving ligand assumes a conformation intermediate between the half chair and the boat forms. The seven-membered ring in the carrier ligand assumes a twist-chair conformation and the oxolane ring assumes an envelope conformation. Crystal packing consists of the extensive hydrogen-bonding network in the two-dimensional molecular layers and weak van der Waals interactions between these layers.

• Advances in Traditional Medicine
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• 제7권4호
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• pp.395-408
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• 2007

This study reports the analgesic, anti-inflammatory and membrane-stabilizing property of alcoholic extract of Ophiorrhiza nicobarica (ON), a wild herb, used as an anti-infective ethnomedicine of Nicobarese and Shompen tribes of Great Nicobar Island, India. We for the first time investigated the analgesic and antiinflammatory potential of this herb in acute, subacute and chronic model of inflammation in Swiss albino mice and Wistar albino rats, along with sheep RBC-induced sensitivity and membrane stabilization. The acetic acid induced writhing, tail flick and tail immersion tests are used as a model for evaluating analgesic activity; while the carrageenin-induced paw oedema was used as the model for acute inflammation, dextran-induced oedema as sub-acute and cotton-pellateinduced granuloma as chronic inflammatory model. The probable mode by which ON mediate its effect on inflammatory conditions was studied on sheep RBC-induced sensitivity and membrane stabilization. The in vitro results revealed that the ON extract possesses significant (P < 0.05) dose dependent analgesic and antiinflammatory activity at 200 and 300 mg/kg and its fractions at 50 mg/kg, p.o. respectively, compared to the control groups. However, the extract failed to exhibit membrane-stabilizing property as it unable to reduce the level of haemolysis of RBC exposed to hypotonic solution. The acute toxicity studies of ON extract in rats and mice revealed that the extract was nontoxic even up to 3.0 g/kg body weight of the animals, with a high safety profile. We have isolated ursolic acid, ${\beta}$-sitosterol and harmaline respectively, from the bioactive part of the extract. The results indicated that the O. nicobarica is indeed beneficial in primary health care, and suggest that its anti-inflammatory activity may not be related to membrane-stabilization.

• 한국전자파학회논문지
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• 제28권4호
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• pp.298-308
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• 2017

본 논문에서는 DC-DC Converter에서의 고조파로 인한 전자기적 잡음을 줄이기 위해 Random PWM을 적용한 Interleaved Buck Converter(IBC) 시스템을 제안한다. PWM 직류전원장치에서 스위칭 방식을 사용하는 경우 스위칭 손실 및 EMI 문제가 발생하기 때문에 많은 고조파를 포함하고 있어 선간 전압의 왜곡 등을 유발한다. 따라서 이에 대한 해결방법으로 PRBS를 이용한 IBC를 최초로 제안한다. 이 방식의 회로 구조는 2개의 능동형 스위치를 가지며 180도의 위상차를 갖는 2개의 PWM 신호를 이용하여 회로를 제어한다. IBC는 1세트의 스위치를 추가하기 때문에, 비용 측면 등에서는 불리 할 수 있으나 전력분배, 출력전류 리플 감소, 빠른 회로 반응속도, 수동소자크기 감소의 이점을 가진다. 본연구의 타당성을 확인하기 위하여 PSIM 시뮬레이터를 이용하였고 Random PWM을 적용한 IBC 회로를 설계하여 기존의 PWM과 RPWM 방식만을 사용하는 Buck-converter 회로를 PSIM 시뮬레이터를 이용하여 결과를 확인하고 분석하였다.

• Asian Pacific Journal of Cancer Prevention
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• 제14권5호
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• pp.3191-3196
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• 2013

Leaf extracts of Cassia alata L (akapulko), traditionally used for treatment of a variety of diseases, were evaluated for their potential antitumor properties in vitro. MTT assays were used to examine the cytotoxic effects of crude extracts on five human cancer cell lines, namely MCF-7, derived from a breast carcinoma, SK-BR-3, another breast carcinoma, T24 a bladder carcinoma, Col 2, a colorectal carcinoma, and A549, a nonsmall cell lung adenocarcinoma. Hexane extracts showed remarkable cytotoxicity against MCF-7, T24, and Col 2 in a dose-dependent manner. This observation was confirmed by morphological investigation using light microscopy. Further bioassay-directed fractionation of the cytotoxic extract led to the isolation of a TLC-pure isolate labeled as f6l. Isolate f6l was further evaluated using MTT assay and morphological and biochemical investigations, which likewise showed selectivity to MCF-7, T24, and Col 2 cells with $IC_{50}$ values of 16, 17, and 17 ${\mu}g/ml$, respectively. Isolate f6l, however, showed no cytotoxicity towards the non-cancer Chinese hamster ovarian cell line (CHO-AA8). Cytochemical investigation using DAPI staining and biochemical investigation using terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL)-a method used to detect DNA fragmentation-together with caspase assay, demonstrated apoptotic cell death. Spectral characterization of isolate f6l revealed that it contained polyunsaturated fatty acid esters. Considering the cytotoxicity profile and its mode of action, f6l might represent a new promising compound with potential for development as an anticancer drug with low or no toxicity to non-cancer cells used in this study.

• The Korean Journal of Physiology and Pharmacology
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• 제20권3호
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• pp.315-324
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• 2016

Human cardiac fibroblasts (HCFs) have various voltage-dependent $K^+$ channels (VDKCs) that can induce apoptosis. Hydrogen peroxide ($H_2O_2$) modulates VDKCs and induces oxidative stress, which is the main contributor to cardiac injury and cardiac remodeling. We investigated whether $H_2O_2$ could modulate VDKCs in HCFs and induce cell injury through this process. In whole-cell mode patch-clamp recordings, application of $H_2O_2$ stimulated $Ca^{2+}-activated$ $K^+$ ($K_{Ca}$) currents but not delayed rectifier $K^+$ or transient outward $K^+$ currents, all of which are VDKCs. $H_2O_2-stimulated$ $K_{Ca}$ currents were blocked by iberiotoxin (IbTX, a large conductance $K_{Ca}$ blocker). The $H_2O_2-stimulating$ effect on large-conductance $K_{Ca}$ ($BK_{Ca}$) currents was also blocked by KT5823 (a protein kinase G inhibitor) and 1 H-[1, 2, 4] oxadiazolo-[4, 3-a] quinoxalin-1-one (ODQ, a soluble guanylate cyclase inhibitor). In addition, 8-bromo-cyclic guanosine 3', 5'-monophosphate (8-Br-cGMP) stimulated $BK_{Ca}$ currents. In contrast, KT5720 and H-89 (protein kinase A inhibitors) did not block the $H_2O_2-stimulating$ effect on $BK_{Ca}$ currents. Using RT-PCR and western blot analysis, three subtypes of $K_{Ca}$ channels were detected in HCFs: $BK_{Ca}$ channels, small-conductance $K_{Ca}$ ($SK_{Ca}$) channels, and intermediate-conductance $K_{Ca}$ ($IK_{Ca}$) channels. In the annexin V/propidium iodide assay, apoptotic changes in HCFs increased in response to $H_2O_2$, but IbTX decreased $H_2O_2$-induced apoptosis. These data suggest that among the VDKCs of HCFs, $H_2O_2$ only enhances $BK_{Ca}$ currents through the protein kinase G pathway but not the protein kinase A pathway, and is involved in cell injury through $BK_{Ca}$ channels.

• 콘크리트학회논문집
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• 제17권2호
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• pp.171-177
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• 2005

철근콘크리트 구조물은 시간이 경과함에 따라 외력의 증가나 환경의 변화 등에 의하여 노후화되고 그 기능을 상실하게 된다. 이러한 구조물의 기능을 회복하기 위하여 보수$\cdot$보강 공법이 적용되고 있다. 본 연구에서는 이러한 보수$\cdot$보강 공법 중프리스트레싱 공법과 단면증설 공법의 특성을 도입한 강연선과 폴리머 모르타르에 의한 보수$\cdot$보강 공법이 적용된 슬래브의 휨 거동특성을 통해 기존 구조물의 보수$\cdot$보강 효과를 파악하였다. 실험은 강연선의 직경, 모르타르의 종류, 치핑 여부, 모르타르 두께, 강연선의 간격 등의 실험변수에 따라 1방향 슬래브 10개, 2방향 슬래브 4개의 시험체를 제작하여 수행하였다. 실험결과 강연선의 간격이 감소할수록 보강효과가 증가하였고, 치핑을 한 경우 콘크리트와 모르타르의 계면에서의 균열이 극한하중 이후에서 발생하였다.