• Journal of Navigation and Port Research
• /
• v.29 no.5 s.101
• /
• pp.475-480
• /
• 2005

Lab scale experimental study was carried out for SBR process, to investigate the effects of influent ship sewage organic compound removal and Bacillus sp. state on design parameters. This process was able to remove nitrogen and phosphorus as well as organic matter efficiently. More than $92.0\%$ of chemical oxygen demand(COD) were removed. In addition, about $84.0\%$ of total nitrogen (T-N) was reduced. The total phosphorus(T-P) reduction averaged $93\%$. The performance load of SBR process was shown to be $0.095kg{\cdot}TOC/m3{\cdot}day$. The pH was decreased from 8.1 to 7.0 within 30 min and increased to 7.3 at the end of anoxic stage, and these phenomena were explained. The sludge produced in the SBR process is characterized by low generation rate (about $0.36kg{\cdot}MLSS/kg{\cdot}TOC$) and excellent settleability. The number of Bacillus sp. in the SBR was $24.2\%$, indicating that Bacillus sp. was a predominant species in the reactor.

• Journal of Korean Society of Environmental Engineers
• /
• v.34 no.1
• /
• pp.55-62
• /
• 2012

The present paper investigates the performance of the KOH aqueous solution as an absorbent to capture carbon dioxide ($CO_2$). The chemical absorption was carried out according to consecutive reactions that are generated in the order of $K_2CO_3$ and $KHCO_3$. The overall absorption was completed with following the physical absorption. When the absorption was conducted with the KOH as the limiting reactants in batch a reactor, $K_2CO_3$ production rate was the 1st order reaction for $OH^-$. However, $KHCO_3$ generation reaction was independent of the $CO_3^{2-}$ concentration and the rate was calculated to be $0.18gCO_2/min$ for all KOH absorbents, which is the same value of the reaction rate using $K_2CO_3$ aqueous solution as the absorbents. The overall $CO_2$ capture ratio of the 5% KOH absorbent was estimated to be 19% and the individual value in section 1 and 2 was 57 and 12%, respectively. The amount of $CO_2$ absorbed in the solution was very slightly less than the theoretical value, which was ascribed to the side reaction that produces $K_2CO_3{\cdot}KHCO_3{\cdot}1.5H_2O$ during the reaction and the consequent diminish in $CO_2$ absorption in the KOH solution.

• Nutrition Research and Practice
• /
• v.12 no.2
• /
• pp.129-134
• /
• 2018

BACKGROUND/OBJECTIVES: Although several recent studies have reported the anti-cancer effects of extracts or components of Citrus unshiu peel, which has been used for various purposes in traditional medicine, the molecular mechanisms for their effects remain unclear. In the present study, the anti-cancer activity of a water-soluble extract of C. unshiu peel (WECU) in MDA-MB-231 human breast carcinoma cells at the level of apoptosis induction was investigated. MATERIALS/METHODS: Cytotoxicity was evaluated using the MTT assay. Apoptosis was detected using DAPI staining and flow cytometry analyses. Mitochondrial membrane potential, reactive oxygen species (ROS) assay, caspase activity and Western blotting were used to confirm the basis of apoptosis. RESULTS: The results indicated that WECU-induced apoptosis was related to the activation of caspase-8, and -9, representative initiator caspases of extrinsic and intrinsic apoptosis pathways, respectively, and caspase-3 accompanied by proteolytic degradation of poly(ADP-ribose) polymerase and down-regulation of the inhibitors of apoptosis protein family members. WECU also increased the pro-apoptotic BAX to anti-apoptotic BCL-2 ratio, loss of mitochondrial membrane potential and cytochrome c release from mitochondria to cytoplasm. Furthermore, WECU provoked the generation of ROS, but the reduction of cell viability and induction of apoptosis by WECU were prevented when ROS production was blocked by antioxidant N-acetyl cysteine. CONCLUSIONS: These results suggest that WECU suppressed proliferation of MDA-MB-231 cells by activating extrinsic and intrinsic apoptosis pathways in a ROS-dependent manner.

• Journal of KIISE
• /
• v.43 no.1
• /
• pp.106-118
• /
• 2016

Recently, as the generation and sharing of web data have increased, the importance of a social semantic web that combines the semantic web and the social web has also been increasing. In this paper, we propose a trust evaluation scheme based on provenance by extending the PROV model in the social semantic web environment. The proposed scheme manages the provenance of web data and adds the necessary elements for trust evaluation in the PROV model of W3C. The extended PROV model supports data management and provenance tracing. The proposed trust evaluation scheme considers various parameters such as user trust, original data trust, and user evaluation. The evaluated trust is managed as provenance. When processing a query, the proposed scheme generates a result by considering the trust. Therefore, the proposed scheme can manage the provenance of web data and compute data trust correctly by using such various parameters. The evaluated trust becomes a criterion to determine whether the query result can be trusted or not. In order to show the validity of the proposed scheme, we verify its performance using SPARQL queries.

• Proceedings of the Korean Vacuum Society Conference
• /
• 2013.08a
• /
• pp.205-205
• /
• 2013

테라헤르쯔(terahertz: THz)파는 0.1~10 THz 의 범위로 적외선과 방송파 사이에 광대역 주파수 스펙트럼을 차지하고 있으며 직진성, 투과성, 그리고 낮은 에너지 (meV)를 가지고 있어 비 파괴적이고 무해한 장점을 지니고 있다. Ti:sapphire laser와 같은 femto-pulse source 등이 많은 발전이 되어 현재 많은 연구와 발전이 이루어지고 있다. femto-pulse source를 이용한 THz 응용에서는 높은 저항, 큰 전자 이동도, 그리고 아주 짧은 전하수명의 기판을 요구하는데 저온에서 성장한 (low-temperature grown : LT) GaAs는 격자 내에 Gallium 자리에 Arsenic이 치환 하면서 AsGa antisite가 발생하여 전하수명을 짧아지는 것을 응용하여 가장 많이 이용되고 있다. 현재 THz 응용분야에서 보다 작고 가격경쟁력이 있는 광통신을 이용한 THz photomixer등이 활발히 연구 하고 있다. 광섬유 내에서 손실과 분산이 최소값을 가지는 부분이 1.55 ${\mu}m$ 부근이고 In0.53Ga0.47As 기판을 이용하였을 때 여기에 완벽하게 만족하게 된다. 하지만 LT-InGaAs 의 경우 AsGa antisite로 인하여 carrier lifetime은 짧아지지만 높은 n-type 전하밀도를 가지게 된다. 이때 Be을 doping하여 전하밀도를 보상하여 높은 저항을 유지해야 하는데 Be의 활성화를 위해서는 열처리를 필요로 한다. 하지만 열처리를 하면 carrier lifetime이 길어지기 때문에 carrier lifetime과 저항을 적절히 조율해야 한다. 이는 물질자체의 특성이기 때문에 InGaAs는 GaAs보다 낮은 amplitude와 짧은 cut-off frequency를 가진다. 본 연구에서는 보다 높은 저항을 얻기 위하여 molecular beam epitaxy를 이용하여 semi-insulating InP:Fe 기판위에 격자 정합된 InGaAs:Be/InAlAs multi quantum well (MQW)를 온도별 ($250{\sim}400^{\circ}C$), 주기별 (50~150)로 성장을 하였고 이때 InGaAs layer의 Be doping level은 $2{\times}1018\;cm^{-3}$, Ex-situ annealing은 $550^{\circ}C$에서 10분으로 고정 하였다. THz 발생 실험에서는 InGaAs/InAlAs MQW은 4000 pA로 1,000 pA를 가지는 InGaAs epilayer보다 4배 높은 전류 신호를 얻을 수 있었고 모든 샘플이 2 THz에서 cut-off frequency를 가지고 있었다. THz 검출 실험에서는 LT-InGaAs:Be epilayer LT-InGaAs:Be/InAlAs, HT-InGaAs/InAlAs 샘플이 각각 180, 9000, 12000 pA의 전류신호를 가지고 있었고 모든 샘플이 2 THz에서 cut-off frequency를 가지고 있었다. HT-InGaAs/InAlAs MQW를 이용한 검출실험에서는 InGaAs layer가 defect free이지만 LT-InGaAs:Be/ InAlAs MQW 보다 높은 전류 신호를 얻을 수 있었다. 이는 InAlAs layer가 저항만 높이는 것뿐만 아니라 carrier trapping layer로써의 역할도 하는 것으로 사료된다.

• Korean Journal of Veterinary Research
• /
• v.35 no.3
• /
• pp.459-469
• /
• 1995

As S-nitrosothiols were proposed as nitrergic carriers in vascular and nonvascular smooth muscle, we have investigated the relaxant properties of several S-nitrosothiols in the porcine retractor penis(PRP) muscle and compared them with the effects of exogenously added NO, electrical field stimulation(EFS) of NANC nerves and sodium nitroprusside(SNP). Also the influences of oxyhemoglobin and hydroquinone on the relaxant responses were investigated. In addition, effects of NO on membrane potentials and its involvement in the generation of inhibitory junction potential(IJP) were investigated with conventional intracellular microelectrode technique. The results were summerized as follows. 1. Frequency-dependent relaxations of PRP muscle were induced by EFS to NANC nerve. Tetrodotoxin($1{\times}10^{-6}M$) abolished the relaxations of PRP muscle induced by EFS, and L-NAME(($2{\times}10^{-5}M$) and methylene blue($4{\times}10^{-5}M$) inhibited the relaxations. L-NAME-induced inhibition of the relaxations was reversed by L-arginine($1{\times}10^{-3}M$), but not by D-arginine. 2. Exogenous NO($1{\times}10^{-5}-1{\times}10^{-4}M$), sodium nitroprusside(($1{\times}10^{-7}-1{\times}10^{-4}M$) induced dose-dependent relaxations of PRP muscle. All S-nitrosothiols($1{\times}10^{-7}-1{\times}10^{-4}M$) tested relaxed the PRP muscle in dose-dependent manner and the potency order was SNAP>GSNO>CysNO>SNAC. 3. Oxyhemoglobin($5{\times}10^{-5}M$) blocked the relaxation induced by exogenous NO and inhibited EFS-, S-nitrosothiols-, and SNP-induced relaxation. 4. Hydroquinone($1{\times}10^{-4}M$) also abolished the relaxations induced by exogenous NO, and reduced the relaxations induced by S-nitrosothiols, but did not affect EFS- and SNP-induced relaxations. 5. SNP($2{\times}10^{-6}-5{\times}10^{-6}M$) relaxed muscle strips but the membrane potentials were not affected. 6. EFS with several pulses(1ms, 2Hz, 80V) produced an inhibitory junction potential(IJP) with muscle relaxation. They were abolished by TTX($2{\times}10^{-6}M$). $N^G$-nitro-$_{\small{L}}$-arginine(L-NNA, $2{\times}10^{-5}M$) abolished the muscle relaxation, but had no effect on IJP.

• Biomolecules & Therapeutics
• /
• v.28 no.5
• /
• pp.443-455
• /
• 2020

The thioredoxin (Trx) system plays critical roles in regulating intracellular redox levels and defending organisms against oxidative stress. Recent studies indicated that Trx reductase (TrxR) was overexpressed in various types of human cancer cells indicating that the Trx-TrxR system may be a potential target for anti-cancer drug development. This study investigated the synergistic effect of auranofin, a TrxR-specific inhibitor, on sulforaphane-mediated apoptotic cell death using Hep3B cells. The results showed that sulforaphane significantly enhanced auranofin-induced apoptosis by inhibiting TrxR activity and cell proliferation compared to either single treatment. The synergistic effect of sulforaphane and auranofin on apoptosis was evidenced by an increased annexin-V-positive cells and Sub-G1 cells. The induction of apoptosis by the combined treatment caused the loss of mitochondrial membrane potential (ΔΨm) and upregulation of Bax. In addition, the proteolytic activities of caspases (-3, -8, and -9) and the degradation of poly (ADP-ribose) polymerase, a substrate protein of activated caspase-3, were also higher in the combined treatment. Moreover, combined treatment induced excessive generation of reactive oxygen species (ROS). However, treatment with N-acetyl-L-cysteine, a ROS scavenger, reduced combined treatment-induced ROS production and apoptosis. Thereby, these results deduce that ROS played a pivotal role in apoptosis induced by auranofin and sulforaphane. Furthermore, apoptosis induced by auranofin and sulforaphane was significantly increased through inhibition of the phosphoinositide 3-kinase (PI3K)/Akt pathway. Taken together, the present study demonstrated that down-regulation of TrxR activity contributed to the synergistic effect of auranofin and sulforaphane on apoptosis through ROS production and inhibition of PI3K/Akt signaling pathway.

• Journal of KIISE:Software and Applications
• /
• v.26 no.11
• /
• pp.1314-1323
• /
• 1999

컴퓨터의 사용이 일반화됨에 따라 데이타를 생성하고 수집하는 것이 용이해졌다. 이에 따라 데이타로부터 자동적으로 유용한 지식을 얻는 기술이 필요하게 되었다. 데이타 마이닝에서 얻어진 지식은 정확성과 이해성을 충족해야 한다. 본 논문에서는 데이타 마이닝을 위하여 퍼지 결정트리에 기반한 효율적인 퍼지 규칙을 생성하는 알고리즘을 제안한다. 퍼지 결정트리는 ID3와 C4.5의 이해성과 퍼지이론의 추론과 표현력을 결합한 방법이다. 특히, 퍼지 규칙은 속성 축에 평행하게 판단 경계선을 결정하는 방법으로는 어려운 속성 축에 평행하지 않는 경계선을 갖는 패턴을 효율적으로 분류한다. 제안된 알고리즘은 첫째, 각 속성 데이타의 히스토그램 분석을 통해 적절한 소속함수를 생성한다. 둘째, 주어진 소속함수를 바탕으로 ID3와 C4.5와 유사한 방법으로 퍼지 결정트리를 생성한다. 또한, 유전자 알고리즘을 이용하여 소속함수를 조율한다. IRIS 데이타, Wisconsin breast cancer 데이타, credit screening 데이타 등 벤치마크 데이타들에 대한 실험 결과 제안된 방법이 C4.5 방법을 포함한 다른 방법보다 성능과 규칙의 이해성에서 보다 효율적임을 보인다.Abstract With an extended use of computers, we can easily generate and collect data. There is a need to acquire useful knowledge from data automatically. In data mining the acquired knowledge needs to be both accurate and comprehensible. In this paper, we propose an efficient fuzzy rule generation algorithm based on fuzzy decision tree for data mining. We combine the comprehensibility of rules generated based on decision tree such as ID3 and C4.5 and the expressive power of fuzzy sets. Particularly, fuzzy rules allow us to effectively classify patterns of non-axis-parallel decision boundaries, which are difficult to do using attribute-based classification methods.In our algorithm we first determine an appropriate set of membership functions for each attribute of data using histogram analysis. Given a set of membership functions then we construct a fuzzy decision tree in a similar way to that of ID3 and C4.5. We also apply genetic algorithm to tune the initial set of membership functions. We have experimented our algorithm with several benchmark data sets including the IRIS data, the Wisconsin breast cancer data, and the credit screening data. The experiment results show that our method is more efficient in performance and comprehensibility of rules compared with other methods including C4.5.

• Journal of Life Science
• /
• v.31 no.7
• /
• pp.662-670
• /
• 2021

Interstitial cells of Cajal (ICCs) are the pacemaking cells in the gastrointestinal (GI) muscles that generate the rhythmic oscillation in membrane potentials known as slow waves. In the present study, we investigated the effects of mirtazapine, a noradrenergic and serotonergic antidepressant, on pacemaking potential in cultured ICCs from the murine small intestine. The whole-cell patch-clamp configuration was used to record pacemaker potential in cultured ICCs. Mirtazapine induced pacemaker potential depolarizations in a concentration-dependent manner in the current clamp mode. Y25130 (a 5-HT3 receptor antagonist), RS39604 (a 5-HT4 receptor antagonist), and SB269970 (a 5-HT7 receptor antagonist) had no effects on mirtazapine-induced pacemaker potential depolarizations. Also, methoctramine, a muscarinic M₂ receptor antagonist, had no effect on mirtazapine-induced pacemaker potential depolarizations, whereas 4-diphenylacetoxy-N-methyl-piperidine methiodide (4-DAMP), a muscarinic M₃ receptor antagonist, inhibited the depolarizations. When guanosine 5'-[β-thio] diphosphate (GDP-β-S; 1 mM) was in the pipette solution, mirtazapine-induced pacemaker potential depolarization was blocked. When an external Ca²⁺ free solution or thapsigargin, a Ca²⁺-ATPase inhibitor of the endoplasmic reticulum, was applied, the generation of pacemaker potentials disappeared, and under these conditions, mirtazapine induced pacemaker potential depolarizations. In addition, protein kinase C (PKC) inhibitor, calphostin C, and chelerythrine inhibited mirtazapine-induced pacemaker potential depolarizations. These results suggest that mirtazapine regulates pacemaker potentials through muscarinic M₃ receptor activation via a G protein-dependent and an external or internal Ca²⁺-independent PKC pathway in the ICCs. Therefore, mirtazapine can control GI motility through ICCs.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• v.32 no.3
• /
• pp.201-206
• /
• 2019

This report constitutes the first demonstration in Korea of single-crystal lateral gallium oxide ($Ga_2O_3$) as a metal-oxide-semiconductor field-effect-transistor (MOSFET), with a breakdown voltage in excess of 480 V. A Si-doped channel layer was grown on a Fe-doped semi-insulating ${\beta}-Ga_2O_3$ (010) substrate by molecular beam epitaxy. The single-crystal substrate was grown by the edge-defined film-fed growth method and wafered to a size of $10{\times}15mm^2$. Although we fabricated several types of power devices using the same process, we only report the characterization of a finger-type MOSFET with a gate length ($L_g$) of $2{\mu}m$ and a gate-drain spacing ($L_{gd}$) of $5{\mu}m$. The MOSFET showed a favorable drain current modulation according to the gate voltage swing. A complete drain current pinch-off feature was also obtained for $V_{gs}<-6V$, and the three-terminal off-state breakdown voltage was over 482 V in a $L_{gd}=5{\mu}m$ device measured in Fluorinert ambient at $V_{gs}=-10V$. A low drain leakage current of 4.7 nA at the off-state led to a high on/off drain current ratio of approximately $5.3{\times}10^5$. These device characteristics indicate the promising potential of $Ga_2O_3$-based electrical devices for next-generation high-power device applications, such as electrical autonomous vehicles, railroads, photovoltaics, renewable energy, and industry.