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      • Influence of different NaOH pretreatment concentrations on saccharification and fermentation for bioethanol production from rice straw and rice husk (natural and powder)

        Shabina Yeasmin,Chul-Hawn Kim,J-Y Lee,M. I. Sheikh,H-J Park,S-H Kim,G-C Kim,J-W Kim 한국펄프·종이공학회 2011 한국펄프·종이공학회 학술발표논문집 Vol.2011 No.4

        The experiment was conducted to evaluate the different NaOH pretreatment concentrations (0.25%, 0.50%, 0.75%, and 1.00%) on enzymatic saccharification (with cellulase, and β-glucosidase) and fermentation (by Saccharomyces cerevisiaeKCCM 11304) for bioethanol production from rice straw and rice husk. Pretreatment of rice straw and rice husk were conducted under both natural and powder state to observe the potentiality of the biomass condition (natural and powder state). In this study, glucose and ethanol production were increased with the increase of NaOH percentage for both rice straw and rice husk (natural and powder state). For rice straw, the highest amount of glucose was obtained in 1.00% NaOH pretreatment (0.81 g g?¹ in a natural, and 0.63 g g?¹ in a powder state pretreatment). Similarly, for rice husk, the highest amount of glucose was obtained in 1.00% NaOH pretreatment (0.47 g g?¹ in a natural, and 0.46 g g?¹ lin a powder state pretreatment). However, 0.75% NaOH pretreatment resulted in glucose yield near about 1.00% NaOH pretreatment for both rice straw and rice husk (natural and powder state). On the other hand, for rice straw, the highest amount of ethanol was obtained in 1.00% NaOH pretreatment (0.36 g g?¹ in a natural, and 0.31 g g?¹ in a powder state pretreatment). In addition, for rice husk, the highest amount of ethanol was also obtained in 1.00% NaOH pretreatment (0.24 g g?¹ in a natural, and 0.23 g g?¹ in a powder state pretreatment). Moreover, 0.75% NaOH pretreatment resulted in ethanol yield near about 1.00% NaOH pretreatment for both rice straw and rice husk (natural and powder state). It was confirmed that higher amount of NaOH use is cost effective. Moreover, higher amount of glucose and ethanol was observed when powder was prepared after pretreatment. So 0.75% NaOH pretreatment in a natural state is supposed to be suitable for enzymatic saccharification and fermentation for bioethanol production.

      • SCISCIESCOPUS

        Gα<sub>12</sub> gep oncogene deregulation of p53-responsive microRNAs promotes epithelial–mesenchymal transition of hepatocellular carcinoma

        Yang, Y M,Lee, W H,Lee, C G,An, J,Kim, E-S,Kim, S H,Lee, S-K,Lee, C H,Dhanasekaran, D N,Moon, A,Hwang, S,Lee, S J,Park, J-W,Kim, K M,Kim, S G Macmillan Publishers Limited 2015 Oncogene Vol.34 No.22

        Hepatocellular carcinoma (HCC) has a poor prognosis owing to aggressive phenotype. Gα<SUB>12</SUB> gep oncogene product couples to G-protein-coupled receptors, whose ligand levels are frequently increased in tumor microenvironments. Here, we report Gα<SUB>12</SUB> overexpression in human HCC and the resultant induction of zinc-finger E-box-binding homeobox 1 (ZEB1) as mediated by microRNA deregulation. Gα<SUB>12</SUB> expression was higher in HCC than surrounding non-tumorous tissue. Transfection of Huh7 cell with an activated mutant of Gα<SUB>12</SUB> (Gα<SUB>12</SUB>QL) deregulated microRNA (miRNA or miR)-200b/a/429, -194-2/192 and -194-1/215 clusters in the miRNome. cDNA microarray analyses disclosed the targets affected by Gα<SUB>12</SUB> gene knockout. An integrative network of miRNAs and mRNA changes enabled us to predict ZEB1 as a key molecule governed by Gα<SUB>12</SUB>. Decreases of miR-200a/b, -192 and -215 by Gα<SUB>12</SUB> caused ZEB1 induction. The ability of Gα<SUB>12</SUB> to decrease p53 levels, as a result of activating protein-1 (AP-1)/c-Jun-mediated mouse double minute 2 homolog induction, contributed to transcriptional deregulation of the miRNAs. Gα<SUB>12</SUB>QL induced ZEB1 and other epithelial–mesenchymal transition markers with fibroblastoid phenotype change. Consistently, transfection with miR-200b, -192 or -215 mimic prevented the ability of Gα<SUB>12</SUB>QL to increase tumor cell migration/invasion. In xenograft studies, sustained knockdown of Gα<SUB>12</SUB> decreased the overall growth rate and average volume of tumors derived from SK-Hep1 cell (mesenchymal-typed). In HCC patients, miR-192, -215 and/or -200a were deregulated with microvascular invasion or growth advantage. In the HCC samples with higher Gα<SUB>12</SUB> level, a correlation existed in the comparison of relative changes of Gα<SUB>12</SUB> and ZEB1. In conclusion, Gα<SUB>12</SUB> overexpressed in HCC causes ZEB1 induction by deregulating p53-responsive miRNAs, which may facilitate epithelial–mesenchymal transition and growth of liver tumor. These findings highlight the significance of Gα<SUB>12</SUB> upregulation in liver tumor progression, implicating Gα<SUB>12</SUB> as an attractive therapeutic target.

      • SCISCIESCOPUS

        Injective colorings of sparse graphs

        Cranston, D.W.,Kim, S.J.,Yu, G. North-Holland Pub. Co ; Elsevier Science Ltd 2010 Discrete mathematics Vol.310 No.21

        Let mad(G) denote the maximum average degree (over all subgraphs) of G and let χ<SUB>i</SUB>(G) denote the injective chromatic number of G. We prove that if mad(G)@?52, then χ<SUB>i</SUB>(G)@?Δ(G)+1; and if mad(G)<4219, then χ<SUB>i</SUB>(G)=Δ(G). Suppose that G is a planar graph with girth g(G) and Δ(G)>=4. We prove that if g(G)>=9, then χ<SUB>i</SUB>(G)@?Δ(G)+1; similarly, if g(G)>=13, then χ<SUB>i</SUB>(G)=Δ(G).

      • SCISCIESCOPUS

        Simulation of single grid-based phase-contrast x-ray imaging (g-PCXI)

        Lim, H.W.,Lee, H.W.,Cho, H.S.,Je, U.K.,Park, C.K.,Kim, K.S.,Kim, G.A.,Park, S.Y.,Lee, D.Y.,Park, Y.O.,Woo, T.H.,Lee, S.H.,Chung, W.H.,Kim, J.W.,Kim, J.G. Elsevier BV * North-Holland 2017 Nuclear Instruments & Methods in Physics Research. Vol. No.

        <P><B>Abstract</B></P> <P>Single grid-based phase-contrast x-ray imaging (g-PCXI) technique, which was recently proposed by Wen et al. to retrieve absorption, scattering, and phase-gradient images from the raw image of the examined object, seems a practical method for phase-contrast imaging with great simplicity and minimal requirements on the setup alignment. In this work, we developed a useful simulation platform for g-PCXI and performed a simulation to demonstrate its viability. We also established a table-top setup for g-PCXI which consists of a focused-linear grid (200-lines/in strip density), an x-ray tube (100-μm focal spot size), and a flat-panel detector (48-μm pixel size) and performed a preliminary experiment with some samples to show the performance of the simulation platform. We successfully obtained phase-contrast x-ray images of much enhanced contrast from both the simulation and experiment and the simulated contract seemed similar to the experimental contrast, which shows the performance of the developed simulation platform. We expect that the simulation platform will be useful for designing an optimal g-PCXI system.</P> <P><B>Highlights</B></P> <P> <UL> <LI> It is proposed for the single grid-based phase-contrast x-ray imaging (g-PCXI) technique. </LI> <LI> We implemented for a numerical simulation code. </LI> <LI> The preliminary experiment with several samples to compare is performed. </LI> <LI> It is expected to be useful to design an optimal g-PCXI system. </LI> </UL> </P>

      • SCISCIESCOPUS

        The gep oncogenes, Gα<sub>12</sub> and Gα<sub>13</sub>, upregulate the transforming growth factor-β1 gene

        Lee, S J,Yang, J W,Cho, I J,Kim, W D,Cho, M K,Lee, C H,Kim, S G Macmillan Publishers Limited 2009 Oncogene Vol.28 No.9

        Transforming growth factor-β1 (TGFβ1) plays a role in neoplastic transformation and transdifferentiation. Gα<SUB>12</SUB> and Gα<SUB>13</SUB>, referred to as the gep oncogenes, stimulate mitogenic pathways. Nonetheless, no information is available regarding their roles in the regulation of the TGFβ1 gene and the molecules linking them to gene transcription. Knockdown or knockout experiments using murine embryonic fibroblasts and hepatic stellate cells indicated that a Gα<SUB>12</SUB> and Gα<SUB>13</SUB> deficiency reduced constitutive, auto-stimulatory or thrombin-inducible TGFβ1 gene expression. In contrast, transfection of activated mutants of Gα<SUB>12</SUB> and Gα<SUB>13</SUB> enabled the knockout cells to promote TGFβ1 induction. A promoter deletion analysis suggested that activating protein 1 (AP-1) plays a role in TGFβ1 gene transactivation, which was corroborated by the observation that a deficiency of the G-proteins decreased the AP-1 activity, whereas their activation enhanced it. Moreover, mutation of the AP-1-binding site abrogated the ability of Gα<SUB>12</SUB> and Gα<SUB>13</SUB> to induce the TGFβ1 gene. Transfection of a dominant-negative mutant of Rho or Rac, but not Cdc42, prevented gene transactivation and decreased AP-1 activity downstream of Gα<SUB>12</SUB> and Gα<SUB>13</SUB>. In summary, Gα<SUB>12</SUB> and Gα<SUB>13</SUB> regulate the expression of the TGFβ1 gene through an increase in Rho/Rac-dependent AP-1 activity, implying that the G-protein-coupled receptor (GPCR)-Gα<SUB>12</SUB> pathway is involved in the TGFβ1-mediated transdifferentiation process.Oncogene (2009) 28, 1230–1240; doi:10.1038/onc.2008.488; published online 19 January 2009

      • Rapid and label-free bioanalytical method of alpha fetoprotein detection using LSPR chip

        Kim, D.,Kim, J.,Kwak, C.H.,Heo, N.S.,Oh, S.Y.,Lee, H.,Lee, G.W.,Vilian, A.T.E.,Han, Y.K.,Kim, W.S.,Kim, G.b.,Kwon, S.,Huh, Y.S. North-Holland Pub. Co 2017 Journal of crystal growth Vol.469 No.-

        Alpha fetoprotein (AFP) is a cancer marker, particularly for hepatocellular carcinoma. Normal levels of AFP are less than 20ng/mL; however, its levels can reach more than 400ng/mL in patients with HCC. Enzyme linked immunosorbent assay (ELISA) and radioimmunoassay (RIA) have been employed for clinical diagnosis of AFP; however, these methods are time consuming and labor intensive. In this study, we developed a localized surface plasmon resonance (LSPR) based biosensor for simple and rapid detection of AFP. This biosensor consists of a UV-Vis spectrometer, a cuvette cell, and a biosensor chip nanopatterned with gold nanoparticles (AuNPs). In our LSPR biosensor, binding of AFP to the surface of the sensor chip led to an increasing magnitude of the LSPR signals, which was measured by an ultraviolet-visible (UV-Vis) spectrometer. Our LSPR biosensor showed sufficient detectability of AFP at concentrations of 1ng/mL to 1μg/mL. Moreover, the overall procedure for detection of AFP was completed within 20min. This biosensor could also be utilized for a point of care test (POCT) by employing a portable UV-Vis spectrometer. Owing to the simplicity and rapidity of the detection process, our LSPR biosensor is expected to replace traditional diagnostic methods for the early detection of diseases.

      • KCI우수등재

        계단형 텅스텐 결정면의 질소 흡착에 관한 연구 : Ⅱ. W(210) 및 W(310)면

        최대선(D. S. Choi),한종훈(J. H. Han),백선목(S. M. Paik),박노길(N. G. Park),김욕욱(Y. W. Kim),황정남(C. N. Whang) 한국진공학회(ASCT) 1996 Applied Science and Convergence Technology Vol.5 No.4

        장전자 방출법으로 텡스텐 (210)면 및 (310)면(100)면의 질소 흡착에 의한 일함수의 변화에 heat of desorption을 측정하였으며 Thermal Desortion Spectra(TDS) 결과로부터 adsorption site를 예측하였다. 텅스텐 (210)면 및 (310)면에 에 질소가 흡착될 때 흡착율에 따라 일함수는 증가하다가 각 면에 대하여 흡착율 5 Langmuir일때 최대 변화량 0.29 eV및 0.20 eV에서 포화되었다. TDS 결과는 이 면들은 낮은 dose의 영역에서 각각 3개의 흡착 site가 있음을 보였으며 이 흡착 site들 중 α₁state의 spectrum의 강도는 (210)면에서 보다 (310)면에서 상대적으로 강해짐을 보였다. 또한 (210)와 (310)면의 α₁ 과 β₂ state의 흡착 site에 흡착된 질소의 dipole moment의 방향은 이 흡착 site들에 대응되는 (100)면의 α₁ 과 β₂state의 흡착 site에 흡착된 질소의 dipole moment의 방향과 반대 방향으로 측정되었으며 이 현상으로부터 질소의 상대적인 흡착 위치를 예측하였다. The heat of desorption and the work function change induced by nitrogen adsorption on the stepped tungstein surface planes, W(210) and W(310), are measured using the Field Electron Emission Microscope(FEM). The adsoption sites are predicted from the Thermal Desortion Spectra(TDS). The work function change of both W(210) and W(310) planes increase as increasing the nitrogen dose and saturates at the nitrogen dose about 5 Langmuir to 0.29 eV and 0.20 ev respectively. We find three adsorption site on each plane for the low dose range. The TDS result shows that the intensity of α₁, state on W(310) is much stronger than that of α₁ state on W(210), and the direction of nitrogen dipole moment adsorbed on the sites correspond to α₁, and β₂ states on W(210) and W(310) planes are in the opposite direction to that of the equivalent states on W(100) plane. From this observation we can predict the relative atomic position in the zdirection (perpendicular direction to the surface) of nitrogen molecules/atoms adsorbed on these sites.

      • 국산밀의 방습평형함수율 모델의 비교 검증

        신동관 ( D. G. Shin ),김태석 ( T. S. Kim ),김훈 ( H. Kim ),이승기 ( S. K. Lee ),김웅 ( W. Kim ),김락우 ( R. W. Kim ),한재웅 ( J. W. Han ) 한국농업기계학회 2021 한국농업기계학회 학술발표논문집 Vol.26 No.2

        일반적으로 밀의 건감율은 벼에 비해 약간 낮은 것으로 알려져 있으나, 국내산 밀의 건조저장시설 설계에 사용할 수 있는 수준의 유용할만한 건조실험 결과보고는 찾아보기 어려운 실정으로서 주요 원인은 밀은 송풍량, 순환속도, 건조기의 제원, 건조공기 및 외기 조건, 물리적특성 등 건조인자에 따라 건조특성이 크게 달라지므로 이러한 건조인자를 모두 고려하여 실험으로 건조특성을 구명하기 어렵다. 건조인자 중 평형함수율은 일정한 조건의 온도 및 상대습도에 장시간 노출될 경우 내부의 수증기압과 주위 공기의 수증기 분압이 평형을 이루게 되어 일정한 함수율에 도달하게 되는데 이때를 평형함수율(Equilibrium Moisture Content, EMC)이라 하며 건조과정 중 수분을 방출하면서 평형 유지할 경우를 방습평형함수율이라 한다. 평형함수율 측정방법에는 온·습도 조성 방법에 따라 동적방법과 정적방법이 있으며 동적 측정방법은 기계적으로 유동시킨 공기 중에 곡물을 노출시켜 평형함수율에 이르게 하여 측정하고 정적 측정방법은 정지된 공기 중에 곡물을 노출시켜 평형상태에 이르게 하는 방법이다. 동적 측정방법은 측정시간이 짧으나 정온·정습의 공기 발생과정이 복잡하고 정적 측정방법은 측정시간이 긴 단점이 있으나 장치가 비교적 간단하다. 따라서 본 연구는 국산밀의 건조에 필요한 방습평형함수율 모델을 정적 측정방법을 이용하여 측정하고 기존 사용되고 있는 모델과 비교하기 위해 수행되었다. 포화염용액은 일정 온도 유지가 가능한 항온기(한국종합기기제작소, HK-BI025, Korea)속에 증류수와 염류를 혼합하여 완전히 포화시켰다. 항온기의 온도는 열전대(T-TYPE, OMEGA, USA)를 설치하고 자료 수집장치(Saveris 2, TESTO, Germany)로 측정하였다. 건조온도 30, 40 및 50℃의 3수준의 온도별 8종류의 염류를 포화시켜 데시케이터 내부의 상대습도(11.0~83.6%)를 유지하여 측정하였다. 상대습도와 온도가 일정하게 유지되는 데시케이터내의 공간에 시료 10g을 담은 시료 접시를 배치하고, 실험 시작 후 2~3일 간격으로 ±0.001g의 전자저울(R420P, Sartorius, Germany)을 이용하여 무게를 측정하였다. 시료의 무게 변화가 2주간 연속해서 0.002g이하의 변화를 보일 때를 평형함수율에 도달한 것으로 간주하였다. 시료의 함수율은 10g-109℃-19h(ASABE standard, 2016) 건조법으로 측정하였다. 평형함수율 측정 후 이용하여 ASABE standard(2016) 밀의 평형함수율인 Modified Chung-Pfost equation과 비교검증한 결과 R2는 0.848 및 RMSE는 1.59 %,d.b.로 낮은 값을 나타내었다. 국산밀의 건조 인자 사용할 경우 국산밀 평형함수율 모델 개발이 필요한 것으로 나타났다.

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