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Nanomeniscus-induced delivery of liquid solutions for diverse nanofiber fabrication
An Sangmin,Kim Bongsu,Kwon Soyoung,Lee Kunyoung,Kim Jongwoo,안희준,제원호 나노기술연구협의회 2015 Nano Convergence Vol.2 No.13
Nanomaterial-delivery fabrication expects high-potential impacts on nanoscience, technology and industry, but still faces limited applicability mainly due to high-field requirement for liquid delivery, complicated intermediate processes, and narrow ink selectivity. Here, we demonstrates a simple, non-template, non-contact and electric field-free fabrication of diverse nanofibers. The process consists of continuous, meniscus-assisted delivery of liquid solutions through a nanoapertured nozzle in ambient conditions, followed by subsequent evaporation of liquid and aggregation of nanoparticle residues. For example, the carbon-nanotube nanofibers of 500 nm diameter exhibit a high shear modulus of ~1.5 GPa and current density up to 10 4 A/cm 2 . The results provide a unique, universal and versatile tool with wide selectivity in both ink and substrate.
Direct-current triboelectric nanogenerator via water electrification and phase control
Kim, Taehun,Kim, Dae Yun,Yun, Junseo,Kim, Banseok,Lee, Seong Hyuk,Kim, Dongseob,Lee, Sangmin Elsevier 2018 Nano energy Vol.52 No.-
<P><B>Abstract</B></P> <P>The recent reputational excellence of triboelectric nanogenerators is based on the idea that they have overcome many limitations for traditional energy harvesting methods. However, in many important respects, these nanogenerators show little promise in addressing the limitations of device efficiency, and in some cases, they threaten the material lifetime. To overcome both efficiency and durability issues, we propose a novel mechanism that generates a DC output via water electrification based on phase control to enhance the sustainability of nanogenerators. Our demonstrations here can enable breakthrough impacts by enhancing device durability with fluid control, generating DC output for energy-loss reduction and providing feasibility with an application model. The advantages of our fluid-controllable DC power nanogenerator can be integrated easily with every energy-harvesting device, thus making it easy for energy-related disciplines to overcome major issues in the more practical way.</P> <P><B>Highlights</B></P> <P> <UL> <LI> It is the report on a new triboelectric nanogenerator (TENG) using water electrification and phase control techniques for a direct-current (DC) power source. </LI> <LI> A numerical simulation of the multiphase flow was conducted to study the electric regimes in the given energy-harvesting system. </LI> <LI> The introduction of our DC-TENG techniques makes it possible to resolve durability and efficiency issues. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>
Kim, Dong-Eog,Kim, Jeong-Yeon,Schellingerhout, Dawid,Ryu, Ju Hee,Lee, Su-Kyoung,Jeon, Sangmin,Lee, Ji Sung,Kim, Jiwon,Jang, Hee Jeong,Park, Jung E.,Kim, Eo Jin,Kwon, Ick Chan,Ahn, Cheol-Hee,Nahrendorf American Heart Association 2017 Stroke Vol. No.
<P>Conclusions-Thromboembolic burden and the efficacy of tPA therapy can be assessed serially, noninvasively, and quantitatively using high-resolution microcomputed tomography and a fibrin-binding nanoparticle imaging agent.</P>
Performance of 3D printed plastic scintillators for gamma-ray detection
Kim, Dong-geon,Lee, Sangmin,Park, Junesic,Son, Jaebum,Kim, Tae Hoon,Kim, Yong Hyun,Pak, Kihong,Kim, Yong Kyun Korean Nuclear Society 2020 Nuclear Engineering and Technology Vol.52 No.12
Digital light processing three-dimensional (3D) printing technique is a powerful tool to rapidly manufacture plastic scintillators of almost any shape or geometric features. In our previous study, the main properties of light output and transmission were analyzed. However, a more detailed study of the other properties is required to develop 3D printed plastic scintillators with expectable and reproducible properties. The 3D printed plastic scintillator displayed an average decay time constants of 15.6 ns, intrinsic energy resolution of 13.2%, and intrinsic detection efficiency of 6.81% for 477 keV Compton electrons from the <sup>137</sup>Cs γ-ray source. The 3D printed plastic scintillator showed a similar decay time and intrinsic detection efficiency as that of a commercial plastic scintillator BC408. Furthermore, the presented estimates for the properties showed good agreement with the analyzed data.
Comparison between screen-detected and symptomatic breast cancers according to molecular subtypes.
Kim, Jiyoung,Lee, SeKyung,Bae, Sooyoun,Choi, Min-Young,Lee, Jeonghui,Jung, Seung Pil,Kim, Sangmin,Choe, Jun-Ho,Kim, Jung-Han,Kim, Jee Soo,Lee, Jeong Eon,Nam, Seok Jin,Yang, Jung-Hyun M. Nijhoff ; Kluwer Academic Publishers 2012 Breast cancer research and treatment Vol.131 No.2
<P>Breast cancer screening programs make it possible to detect early cancer, thus reducing breast cancer mortality. We studied the clinicopathologic characteristics and prognosis of screen-detected invasive breast cancer compared with symptomatic breast cancer. And we compared the result according to molecular subtypes (luminal A, luminal B, Her2, and triple negative), with the goal of identifying the role of screening in each subtypes. From January 2002 to June 2008, 3,141 patients who underwent surgery for the treatment of invasive ductal carcinoma at Samsung Medical Center were included. Among them, 1,025 patients were screen-detected, and 2,116 patients who were screened over 2 years or never were symptomatic. We retrospectively reviewed the clinical and pathologic data. Screen-detected breast cancer was associated with older age, smaller tumor size, more hormone-receptor positive, less lymph node involvement, earlier stage, and reduced mortality compared with symptomatic breast cancer (P < 0.001). According to the molecular subtype, luminal A was most common (63.6%) and showed the most obvious survival benefit in screen-detected tumors in comparison with symptomatic tumors (5-year OS: 99.7 vs. 96.5%, 5-year DFS: 96.4 vs. 90.7%). Screen detection was independently associated with improved overall and disease-free survival outcomes after adjustment for covariates (HR 0.32, P = 0.035; HR 0.58, P = 0.020, respectively) only in the luminal A subtype. Differences in pathological features such as tumor size, nodal status, grade, and age at diagnosis with different molecular subtype distributions may explain the survival advantage of patients with screen-detected breast cancer. Screening programs seem to have a different efficacy depending on the molecular subtype of the breast cancer, especially in the luminal A subtype, for which screen detection acts as an independent prognostic factor itself.</P>
Effect of berberine on p53 expression by TPA in breast cancer cells.
Kim, Sangmin,Han, Jeonghun,Kim, Nam-Young,Lee, Se Kyung,Cho, Dong Hui,Choi, Min-Young,Kim, Jee Soo,Kim, Jung-Han,Choe, Jun-Ho,Nam, Seok Jin,Lee, Jeong Eon National Hellenic Research Foundation 2012 Oncology reports Vol.27 No.1
<P>Berberine (BBR), an isoquinoline derivative alkaloid compound, has been reported to have anti-oxidant and anti-carcinogenic effects. A loss of functional p53 is involved with an increased risk of cancer proliferation and metastasis. Here, we investigated the effect of BBR on the transcriptional activity and the protein expression of p53 in p53-positive (wild- type, MCF7 cells) and p53-negative (mutant, MDA-MB231 cells) human breast cancer cells. Our results showed that the basal level of p53 mRNA and protein expression was increased by BBR treatment. However, tumor promoter, TPA, decreased the level of p53 mRNA and protein expression in MCF7 cells with wild-type p53. In addition, TPA-induced down-regulation of p53 mRNA and protein expression was increased by UO126, but not by SP600125 and SB203580. To verify the regulatory mechanism of p53 protein expression, we investigated the effects of proteasomal inhibitors (ALLN and MG132) or a lysosomal inhibitor (chloroquine) on TPA-induced down-regulation of p53. We observed that TPA-induced down-regulation of p53 protein was prevented by ALLN and MG132, but not by chloroquine. Further, we investigated the effect of BBR on TPA-induced down-regulation of p53 mRNA and protein levels. Interestingly, the levels of TPA-induced down-regulation of p53 mRNA and protein were prevented by BBR, but MDA-MB231 cells with mutated p53 were not affected. In addition, TPA-induced down-regulation of p53 mRNA was also prevented by BBR. Taken together, we suggest that BBR may be used as an effective ingredient for anticancer products, which trigger the transcriptional activity and the inhibition of the degradation of p53, a tumor suppressor gene, in human breast cancer.</P>
Kim, Sangmin,Han, Jeonghun,Kim, Jee Soo,Kim, Jung-Han,Choe, Jun-Ho,Yang, Jung-Hyun,Nam, Seok Jin,Lee, Jeong Eon Potamitis Press 2011 Anticancer research Vol.31 No.11
<P>CD44, the transmembrane receptor for hyaluronan, is implicated in tumor cell invasion and metastasis. The expression of CD44 and its variants is associated with poor prognosis in breast cancer. Here, we investigated the effect of silibinin (a polyphenolic flavonolignan of the herbal plant of Silybum marianum, milk thistle) on the epidermal growth factor (EGF) ligand-induced CD44 expression in human breast cancer cells. The levels of CD44 mRNA and protein expression were greatly increased by EGF and by TGF-α in SKBR3 and BT474 breast cancer cells. In contrast, EGFR ligand-induced CD44 expression was reduced by EGFR inhibitors, AG1478 and lapatinib, respectively. Interestingly, we observed that EGFR ligand-induced CD44 and matrix metalloproteinase-9 (MMP-9) expression was reduced by silibinin treatment in a dose-dependent manner. In addition, silibinin suppressed the EGF-induced phosphorylation of EGFR and extracellular signal-regulated kinase1/2 (ERK1/2), a downstream signaling molecule of EGFR. Therefore, we suggest that silibinin prevents the EGFR signaling pathway and may be used as an effective drug for the inhibition of metastasis of human breast cancer.</P>
Cholesterol inhibits MMP-9 expression in human epidermal keratinocytes and HaCaT cells
Kim, Sangmin,Kim, Yoonkyung,Lee, Youngae,Cho, Kwang Hyun,Kim, Kyu Han,Chung, Jin Ho Elsevier 2007 FEBS letters Vol.581 No.20
<P><B>Abstract</B></P><P>Cholesterol is a major component of skin lipids and acts as a regulator of vesicular trafficking and signal transduction. However, the function of cholesterol on matrix metalloproteinases (MMPs) expression of human skin is not fully understood. Here, we investigated the effects of cholesterol on MMP-9 expression in normal human keratinocytes (NHK) and HaCaT cells. Basal level of MMP-9 expression was decreased by cholesterol in NHK. On the other hand, MMP-9 expression was increased by the cholesterol depletion agent, methyl-β-cyclodextrin (MβCD), while it was inhibited by cholesterol repletion in HaCaT cells. MβCD induced ERK and JNK phosphorylation were prevented by cholesterol repletion. The inhibition of ERK and JNK decreased MβCD-induced MMP-9 expression. Therefore, our results suggest that cholesterol regulates MMP-9 expression through ERK and JNK-dependent pathways.</P>