O/W · W/O Emulsion의 Tribology 특성 연구

이봉구,임웅빈,오성모 원광대학교 생산 및 자동화기술연구소 1995 생산.자동화기술연구소논문집 : 원광대 Vol.- No.2

We have been so much interested in the lubrication of emulsion property recently. In particular, O/W and W/O type emulsion have a good property to be used in the Lubricative situation of several services. Therefore, in this section we have studied about the lubricational characteristics in Neat Oil, O/W and W/O type emulsion using the Falex, wear test machine. The result is as follows. 1. In the case of O/W and W/O type emulsion, the beginning friction coefficient than Neat Oil, but it becomes more excellent as the time passes. especially, the W/O type becomes the more excellent. 2. As the load increase, a change in temperature shows to us be nearly similar and all of them, the O/W type is the most excellent in the temperature characteristic. 3. In the beginning, the anti-wear characteristic of emulsion lowers, but after the some load has stability, O/W and W/O type is excellent in order of anti-wear characteristic. 4. In the regular hours, a change in the emulsion becomes settled, so the character of temperature is superior. specially, O/W type is predominant. Therefore, the emulsion in case of the O/W and W/O type are more excellent than Neat oil in the thermal stability and can improve the characteristics of tribology.

Gα₁₂ 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.

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.

Characteristic polynomial of a generalized complete product of matrices

Hwang, S.G.,Park, J.W. North Holland [etc.] 2011 Linear algebra and its applications Vol.434 No.5

For a simple graph G, let G@? denote the complement of G relative to the complete graph and let P<SUB>G</SUB>(x)=det(xI-A(G)) where A(G) denotes the adjacency matrix of G. The complete product G@?H of two simple graphs G and H is the graph obtained from G and H by joining every vertex of G to every vertex of H. In [2]P<SUB>G@?H</SUB>(x) is represented in terms of P<SUB>G</SUB>, P<SUB>G@?</SUB>, P<SUB>H</SUB> and P<SUB>H@?</SUB>. In this paper we extend the notion of complete product of simple graphs to that of generalized complete product of matrices and obtain their characteristic polynomials.

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).

The gep oncogenes, Gα₁₂ and Gα₁₃, 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

표면항원 및 유전자분석에 의한 V. vulnificus균의 계통분류학적 연구(Ⅰ) : 지방산 조성 및 RAPD PCR에 의한 V. vulnificus균의 계통분류학적 연구

윤영희,김기상,신영학,이점규,오경수,유정식,이상원,이근용 국립보건연구원 1998 국립보건원보 Vol.35 No.-

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.

LIGA-like 공정을 이용한 마이크로 부품 복제용 Ni과 Ni-W 금형 제조 및 특성

황완식,박준식,강영철,조진우,박순섭,이인규,강성군,Hwang, W.S.,Park, J.S.,Kang, Y.C.,Cho, J.W.,Park, S.S.,Lee, I.G.,Kang, S.G. 한국재료학회 2003 한국재료학회지 Vol.13 No.1

Electroplated Ni and Ni-W micro-molds using LIGA-like process for replication of micro-components such as microfluidic parts and micro optical parts have been investigated. In general, it is hard to produce micro-parts using conventional mechanical processes. Micro-mold formed by LIGA-like process could fabricate micro-parts with high aspect ratio. In this paper, fabrication and properties of electroplated Ni molds with varying applied current types as well as those of Ni-W molds were investigated. Ni molds fabricated under pulse-reverse current showed the highest hardness value of about 160 Hv. Ni-W molds showed the hardness of about 500 Hv which was much harder than that of Ni electroplated molds. The above results suggested that high quality micro-molds could be fabricated by using Ni electroplating of pulse-reverse type for core molds and sequential Ni-W alloys coating.

Molecular cloning and expression of cDNAs for two distinct granulocyte colony stimulating factor genes from black rockfish Sebastes schlegelii

Nam, B.H.,An, G.H.,Baeck, G.W.,Kim, M.C.,Kim, J.W.,Park, H.J.,Lee, D.C.,Park, C.I. Academic Press 2009 FISH AND SHELLFISH IMMUNOLOGY Vol.27 No.2

Granulocyte-colony stimulating factor (G-CSF) is a cytokine that stimulates the proliferation and differentiation of hematopoietic progenitor cells committed to the neutrophil/granulocyte lineage. Here, we report the two distinct granulocyte colony stimulating factor homologues from black rockfish Sebastes schlegelii. The G-CSF homologue cDNAs were isolated from the black rockfish LPS or Con A/PMA stimulated leukocyte cDNA libraries. The cDNA for the Black rockfish G-CSF-1 homologue predicts a peptide of 202 amino acids that is the closest to the Bastard halibut (Paralichthys olivaceus) G-CSF, whereas the cDNA of the Black rockfish G-CSF-2 homologue predicts a peptide of 212 amino acids that is the closest to the Fugu (Takifugu rubripes). In a healthy fish, the mRNAs of both G-CSF homologues were predominantly expressed in leukocytes, spleen, and gill. Expression of the black rockfish G-CSF-1 homologue was induced in peripheral blood leukocytes (PBLs) after stimulation with LPS, Con A/PMA, or Poly I:C, and G-CSF-2 homologue was strongly induced in PBLs after stimulation with Con A/PMA for 24 h only.