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김동준,정종문,김정현,황하청,정재윤,조윤희,임현교,구제환,최은하,조광섭,Jin, D.J.,Jeong, J.M.,Kim, J.H.,Hwang, H.C.,Chung, J.Y.,Cho, Y.H.,Lim, H.K.,Koo, J.H.,Choi, E.H.,Cho, G.S. 한국진공학회 2010 Applied Science and Convergence Technology Vol.19 No.1
관경이 수 mm인 세관 램프 내부에서 플라즈마의 확산을 조사하기 위하여 이극성(ambipolar) 확산방정식을 해하였다. 반경 방향의 확산에 의한 유리관 벽에서의 플라즈마 소멸 특성시간은 $\tau_r\;=\;(r_0/2.4)^2/D_a$로 주어진다. 반경 $r_0{\sim}1\;mm$이고 이극성 확산계수 $D_a{\sim}0.01\;m^2/s$ 이면, $\tau_r{\sim}17\;{\mu}s$이다. 이는 램프의 교류전원 구동에서 플라즈마를 유지하기 위한 구동 최소 주파수 ~30 kHz에 해당한다. 고전압이 인가되는 전극부에 발생한 고밀도의 플라즈마가 양광주로 확산되는 특성시간은 $\tau_z{\sim}0.1\;s$이다. 고밀도 플라즈마 경계에서의 시간에 대한 확산속도는 $t{\sim}10^{-6}\;s$일 때 $u_D{\sim}10^2\;m/s$이고, $t{\sim}10^{-3}\;s$이면 그 속도는 $u_D{\sim}1\;m/s$로 느려진다. 따라서 램프 길이 ~1 m에 대하여 전극부에서 생성된 고밀도 플라즈마가 양광주 전체로 확산되는 시간은 수 초가 걸린다. The ambipolar diffusion equation has been solved in a fine-tube lamp of a few mm in diameter. In the diffusion of radial direction, the plasma diffuses and vanishes away at the glass wall by recombination with the characteristic time of plasma loss is given by $\tau_r\;=\;(r_0/2.4)^2/D_a$. With the radius $r_0{\sim}1\;mm$ and the ambipolar diffusion coefficient $D_a{\sim}0.01\;m^2/s$, the vanishing time is calculated $\tau_r{\sim}10\;{\mu}s$ which corresponds to the least value of frequency 30 kHz for the sustaining the plasma in the operation of high voltage AC-power. In the diffusion of longitudinal z-direction, a high density plasma generated at the area of a high voltage electrode, diffuses into the positive column with the characteristic time $\tau_z{\sim}0.1\;s$. The plasma diffusion velocity at the boundary of high density plasma is $u_D{\sim}10^2\;m/s$ at the time $t{\sim}10^{-6}$ s and the diffusion velocity becomes slow as $u_D{\sim}1\;m/s$ at $t{\sim}10^{-3}\;s$. Therefore, for the long lamp of 1 m, it takes about several seconds for the high density plasma at the area of electrode to diffuse through the whole positive column space.
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Piao, D.C.,Lee, Y.S.,Bok, J.D.,Cho, C.S.,Hong, Z.S.,Kang, S.K.,Choi, Y.J. Academic Press 2016 Protein expression and purification Vol.126 No.-
The emergence of highly pathogenic variant porcine epidemic diarrhea virus (PEDV) strains, from 2013 to 2014, in North American and Asian countries have greatly threatened global swine industry. Therefore, development of effective vaccines against PEDV variant strains is urgently needed. Recently, it has been reported that the N-terminal domain (NTD) of S1 domain of PEDV spike protein is responsible for binding to the 5-N-acetylneuraminic acid (Neu5Ac), a possible sugar co-receptor. Therefore, the NTD of S1 domain could be an attractive target for the development of subunit vaccines. In this study, the NTD spanning amino acid residues 25-229 (S25-229) of S1 domain of PEDV variant strain was expressed in Escherichia coli BL21 (DE3) in the form of inclusion bodies (IBs). S25-229 IBs were solubilized in 20 mM sodium acetate (pH 4.5) buffer containing 8 M urea and 1 mM dithiothreitol with 95% yield. Solubilized S25-229 IBs were refolded by 10-fold flash dilution and purified by one-step cation exchange chromatography with >95% purity and 20% yield. The CD spectrum of S25-229 showed the characteristic pattern of alpha helical structure. In an indirect ELISA, purified S25-229 showed strong reactivity with mouse anti-PEDV sera. In addition, immunization of mice with 20 μg of purified S25-229 elicited highly potent serum IgG titers. Finally, mouse antisera against S25-229 showed immune reactivity with native PEDV S protein in an immunofluorescence assay. These results suggest that purified S25-229 may have potential to be used as a subunit vaccine against PEDV variant strains.
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Kim, D.S.,Choi, J.S.,Kim, D.W.,Kim, K.S.,Seo, Y.G.,Cho, K.H.,Kim, J.O.,Yong, C.S.,Youn, Y.S.,Lim, S.J.,Jin, S.G.,Choi, H.G. Elsevier/North Holland 2016 International journal of pharmaceutics Vol.511 No.1
The purpose of this study was to compare the powder properties, solubility, dissolution and oral absorption of solvent@?wetted (SWSD) and kneaded (KNSD) l-sulpiride@?loaded solid dispersions. The SWSD and KNSD were prepared with silicon dioxide, sodium laurylsulfate and D-α-tocopheryl polyethylene glycol 1000 succinate (TPGS) using a spray dryer and high shear mixer, respectively. Their powder properties, solubility, dissolution and oral absorption were assessed compared to l-sulpiride powder. The drug in SWSD was in the amorphous state; however, in KNSD, it existed in the crystalline state. The SWSD with a drug/sodium laurylsulphate/TPGS/silicon dioxide ratio of 5/½/12 gave the higher drug solubility and dissolution compared to the KNSD with the same composition. The oral absorption of drug in the SWSD was 1.4 fold higher than the KNSD and 3.0 fold higher than the l-sulpiride powder (p<0.05) owing to better solubility and reduced crystallinity. Furthermore, the SWSD at the half dose was bioequivalent of commercial l-sulpiride@?loaded product in rats. Thus, the SWSD with more improved oral absorption would be recommended as an alternative for the l-sulpiride@?loaded oral administration.
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Song, D‐,S.,Park, J‐,C.,Jung, I‐,H.,Choi, S‐,H.,Cho, K‐,S.,Kim, C‐,K.,Kim, C‐,S. Blackwell Publishing Ltd 2011 Journal of periodontal research Vol.46 No.2
<P> <I>Song D‐S, Park J‐C, Jung I‐H, Choi S‐H, Cho K‐S, Kim C‐K, Kim C‐S. Enhanced adipogenic differentiation and reduced collagen synthesis induced by human periodontal ligament stem cells might underlie the negative effect of recombinant human bone morphogenetic protein‐2 on periodontal regeneration. J Periodont Res 2011; 46: 193–203. © 2010 John Wiley & Sons A/S</I> </P><P><B>Background and Objective: </B> Recombinant human bone morphogenetic protein‐2 (rhBMP‐2) is a potent inducer for the regeneration of mineralized tissue, but has a limited effect on the regeneration of cementum and periodontal ligament (PDL). The aim of the present study was to determine the effects of rhBMP‐2 on the <I>in vitro</I> and <I>in vivo</I> biologic activity of well‐characterized human PDL stem cells (hPDLSCs) and to elucidate the underlying mechanism of minimal periodontal regeneration by rhBMP‐2.</P><P><B>Material and Methods: </B> hPDLSCs were isolated and cultured, and then transplanted into an ectopic subcutaneous mouse model using a carrier treated either with or without rhBMP‐2. Comprehensive histologic, histometric and immunohistochemical analyses were performed after an 8‐wk healing period. The effects of rhBMP‐2 on the adipogenic and osteogenic/cementogenic differentiation of hPDLSCs were also evaluated. The effect of rhBMP‐2 on both soluble and insoluble collagen synthesis was analyzed, and the expression of mRNA and protein for collagen types I, II, III and V was assessed.</P><P><B>Results: </B> In the present study, rhBMP‐2 promoted both adipogenic and osteogenic/cementogenic differentiation of hPDLSCs <I>in vitro</I>, and the <I>in vivo</I> potential of hPDLSCs to form mineralized cementum and organized PDL tissue was down‐regulated following treatment with rhBMP‐2. Collagen synthesis, which plays a crucial role in the regeneration of cementum and the periodontal attachment, was significantly reduced, with associated modification of the relevant mRNA and protein expression profiles.</P><P><B>Conclusion: </B> In summary, the findings of the present study suggest that enhanced adipogenic differentiation and inhibition of collagen synthesis by hPDLSCs appear to be partly responsible for the minimal effect of rhBMP‐2 on cementum and PDL tissue regeneration by hPDLSCs.</P>
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Clinical outcomes of venous thromboembolism with dalteparin therapy in multiple myeloma patients
Lee, S.E.,Jeon, Y.W.,Yoon, J.H.,Cho, B.S.,Eom, K.S.,Kim, Y.J.,Kim, H.J.,Lee, S.,Cho, S.G.,Kim, D.W.,Lee, J.W.,Min, W.S.,Kim, M.,Min, C.K. Pergamon Press 2015 Thrombosis research Vol.136 No.5
This study focused on the clinical outcomes in multiple myeloma (MM) patients with venous thromboembolism (VTE) who received low-molecular-weight heparin (dalteparin) therapy. Changes in D-dimer levels before and after VTE were also evaluated. Among 549 patients treated with various chemotherapeutic agents, a total of 52 (9.47%) patients including 32 newly diagnosed with MM and 16 with relapsed/refractory MM developed VTE, 48 of whom received dalteparin. Among the 48 treated patients, 37 (77%) had proximal deep vein thrombosis (DVT), four had (8%) pulmonary embolism (PE), and seven (15%) had both DVT and PE. In 32 patients with available paired samples (at baseline and VTE occurrence), significant conversion of D-dimer levels from 2.2+/-0.4mg/L to 11.8+/-1.6mg/L (P<0.001) was observed, which decreased from 10.9+/-0.4mg/L to 1.9+/-0.6mg/L one month after initiating dalteparin therapy. A total of 44 patients received dalteparin with a median duration of 4.2months (range, 2.7-9.4), and four patients were discontinued early due to death (n=3) and major bleeding (n=1). After a median follow-up of 9.0months (range, 0.7-35.8) since the first VTE episode, five patients showed recurrence of VTE with a cumulative incidence of 17.5+/-7.9%. Major bleeding occurred in three patients. In summary, dalteparin seems to be a promising drug for the treatment of VTE in MM. In addition, the significant difference in D-dimer levels observed before occurrence of VTE and after dalteparin treatment may suggest the usefulness of D-dimer testing as a surrogate marker for VTE in MM patients.
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Kim, S.M.,Lee, S.Y.,Cho, J.S.,Son, S.M.,Choi, S.S.,Yun, Y.P.,Yoo, H.S.,Yoon, D.Y.,Oh, K.W.,Han, S.B.,Hong, J.T. North-Holland ; Elsevier Science Ltd 2010 european journal of pharmacology Vol.631 No.1
Ginsenoside Rg3 has been a subject of interest for use as a cancer preventive or therapeutic agent. Nuclear factor-kappa (NF-κB) is constitutively activated in prostate cancer, and gives cancer cells resistance to chemotherapeutic agents. To investigate whether Rg3 can suppress the activation of NF-κB, and thus increase susceptibility of prostate (LNCaP and PC-3, DU145) cells against chemotherapeutics, prostate cancer cell growth as well as activation of NF-κB was examined. We found that a combination treatment of Rg3 (50@?M) with a conventional agent docetaxel (5nM) was more effective in the inhibition of prostate cancer cell growth and induction of apoptosis as well as G<SUB>0</SUB>/G<SUB>1</SUB> arrest accompanied with the significant inhibition of NF-κB activity than those by treatment of Rg3 or docetaxel alone. It was also found that NF-κB target gene expression of Bax, caspase-3, and caspase-9 was much more significantly enhanced, but the expression of Bcl-2, inhibitor of apoptosis protein (IAP-1) and X chromosome IAP (XIAP), and the expression of cell cycle regulatory proteins cyclin B, D1 and E, and cyclin dependent kinases 2 and 4 was also much more significantly inhibited by the combination treatment. The combination of Rg3 (50@?M) with cisplatin (10@?M) and doxorubicin (2@?M) was also more effective in the inhibition of prostate cancer cell growth and NF-κB activity than those by the treatment of Rg3 or chemotherapeutics alone. These results indicate that ginsenoside Rg3 inhibits NF-κB, and enhances the susceptibility of prostate cancer cells to docetaxel and other chemotherapeutics. Thus, ginsenoside Rg3 could be useful as an anti-cancer agent.
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Effect of bedrock stiffness and thickness of weathered rock on response spectrum in Korea
Manandhar, S.,Cho, H. I.,Kim, D. S. Springer Science + Business Media 2016 KSCE JOURNAL OF CIVIL ENGINEERING Vol.20 No.7
<P>The Standard Penetration Test (SPT) is increasingly used to generate shear wave velocity (V (S) ) profile of a site for seismic hazard assessment. However, it is difficult to perform site investigation using the SPT for weathered rock and bedrock even at shallow depths in most cases. Consequently, the stiffness of bedrock (V (Sb) ) is assumed to be 760 m/s, and only partial thickness of weathered rock is used for site response assessment in Korea. The increase in V (Sb) and thickness of weathered rock (H (w) ) may affect the overall seismic response of a site, even though the site response is mostly governed by the upper soil layers. In this study, the effect of V (Sb) and H (w) on response spectrum in Korea was investigated by performing equivalent-linear site response analyses on three representative sites each of S (C) and S (D) soil categories as defined in the Korean seismic code based on the average shear wave velocity of top 30 m of a site (V-S30). The S (C) and S (D) categories are defined similar to that in the International Building Code (IBC). Further, the effect of increase in V-Sb and H-w on the selection of design response spectrum based on seismic codes was also investigated. An increase in V (Sb) resulted in an increase in spectral amplification, while the effect of increase in H-w was not substantial for the representative sites considered in this study. This means that the V (S) of bedrock needs to be assessed properly. On the other hand, it is possible to get a reliable seismic response even if the H-w cannot be determined accurately. The incorporation of V (Sb) in V (S30) for shallow bedrock sites (bedrock depth < 30 m) fails to consider the effect of increase in seismic amplification at large V (Sb) . Hence, it is preferable to consider the effect of V (Sb) separately on the design response spectrum. In addition, the effect on soil non-linearity due to variation in the V (Sb) and H (w) was found to be insignificant.</P>
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