Self-standing and shape-memorable UV-curing epoxy polymers for three-dimensional (3D) continuous-filament printing

Sun, H.,Kim, Y.,Kim, Y. C.,Park, I. K.,Suhr, J.,Byun, D.,Choi, H. R.,Kuk, K.,Baek, O. H.,Jung, Y. K.,Choi, H. J.,Kim, K. J.,Nam, J. D. The Royal Society of Chemistry 2018 Journal of materials chemistry. C, Materials for o Vol.6 No.12

<P>In the development of three-dimensional printable materials for high-speed and high-resolution printing, UV-curing polymers can guarantee fast and precise printing of high performance load-bearing structures, but the injected drops of the monomers tend to spread over the substrates due to their low viscosity. In this study, we imposed the self-standing and shape-memorable capability of an epoxy acrylate (EA) monomer to ensure continuous filamentary 3D printing while maintaining its low viscosity nature. Using octadecanamide (ODA) with EA, strong hydrogen-bond networks (−N−H⋯OC−, −N−CO⋯H-O-, -N-H⋯N-) were additionally achieved in the material system and the developed material distinctively exhibited rheological duality at different processing stages: a low-viscosity liquid-like behavior (viscosity of ∼50 Pa) while passing through the nozzle and a self-standing solid-like behavior (static yield stress of ∼364 Pa) right after being printed. This reversible liquid-to-solid transitional capability was quantified by viscoelastic complex moduli provided a dynamic yield stress (<I>τ</I>y,G) of 210 Pa corresponding to the upright stacking up to ∼3.2 cm (3 wt% of ODA). The time (<I>t</I>y,G) required for conformational rearrangement was evaluated to be as fast as ∼10<SUP>−2</SUP> s. After UV curing, the 3D printed layers exhibited no air pockets or weld lines at the stacked interfaces, which could guarantee excellent mechanical performance and structural integrity.</P>

Improving mechanical and magnetocaloric responses of amorphous melt-extracted Gd-based microwires via nanocrystallization

Belliveau, H.F.,Yu, Y.Y.,Luo, Y.,Qin, F.X.,Wang, H.,Shen, H.X.,Sun, J.F.,Yu, S.C.,Srikanth, H.,Phan, M.H. Elsevier 2017 JOURNAL OF ALLOYS AND COMPOUNDS Vol.692 No.-

<P><B>Abstract</B></P> <P>We report on the structural, mechanical, and magnetocaloric properties of annealed melt-extracted Gd<SUB>53</SUB>Al<SUB>24</SUB>Co<SUB>20</SUB>Zr<SUB>3</SUB> amorphous microwires of ∼70 μm diameter. During heat treatment small islands of nanocrystallities are generated and isolated in the amorphous region for the wires. The size of the nanocrystallities ranges from 5 nm to 10 nm. The observed lattice distortion from the nanocrystallities causes changes in the magnetic properties of the wires. The annealing temperature of 100 °C has the largest strength (1845 MPa) as compared to wires annealed at other temperatures. This is likely to trigger nanophase transformation in the amorphous region and these nanocrystals have been preserved through the increase of annealing temperature. The formulation of the nanocrystalline islands is also verified by the selected-area electron diffraction (SAED). The microwires exhibit a large and reversible magnetocaloric effect (MCE), with the maximum isothermal magnetic entropy change (−Δ<I>S</I> <SUB>M</SUB>) and refrigerant capacity (<I>RC</I>) values of 9.5 J/kg K and 689 J/kg respectively for the microwire annealed at 100 °C. This <I>RC</I> is about 35%, 67%, and 91% larger than those of bulk Gd<SUB>53</SUB>Al<SUB>24</SUB>Co<SUB>20</SUB>Zr<SUB>3</SUB> (∼509 J/kg), Gd (∼410 J/kg), and Gd<SUB>5</SUB>Si<SUB>2</SUB>Ge<SUB>1.9</SUB>Fe<SUB>0.1</SUB> (∼360 J/kg) regardless of their ordering temperatures. These results demonstrate the ability to tune the mechanical and magnetic properties of the microwires by thermal annealing.</P> <P><B>Highlights</B></P> <P> <UL> <LI> The impact of nanocrystallization in Gd<SUB>53</SUB>Al<SUB>24</SUB>Co<SUB>20</SUB>Zr<SUB>3</SUB> microwires. </LI> <LI> Enhanced mechanical strength. </LI> <LI> Enhanced magnetocaloric response. </LI> </UL> </P>

Formation of a Wide Area of Diamond Film Using HFCVD: Ⅱ. Effect of Applied Negative Bias on Nucleation

Song, G.H.,Yoon, J.H.,Shin, K.S.,Kim, H.S.,Sun, C.,Huang, R.F.,Wen, L.S. 국립7개대학공동논문집간행위원회 2003 공업기술연구 Vol.3 No.-

The nucleation and nucleus shape of diamond films on silicon (100) has been investigated by varying the negative bias value applied to substrate during Hot Filament Chemical Vapor Deposition (HFCVD). Results showed that the nucleation density increased, peaked and then decreased with increase of the applied bias value. it seemed that there was an optimum bias value. The nucleation of diamond film by HFCVD is a competitive process of deposition and etchings (sputtered) due to the particles impinging on the substrate. The magnitude of the energy, quantity of the particles and the ratio of carbon to hydrogen in reactive gas plasma controlled the competitive process and determined which process was primary. The deposition rate and the nucleation density gradually increased reaching to a maximum with the increment of the energy of the adatoms. With further increment of the energy of the adatoms, however, the deposition process was suppressed by strengthened particle impact on the substrate and the etching or sputtering became the primary process. Experimental results also showed the nucleus crystal shape of diamond films sequentially changed from cubic to dodecahedron, and then to irregular shape with the increment of the bias value. The change of the nucleus crystal shape of diamond films with substrate bias is thought to be related to the each process of the H+ ion with different kinetic energy, as well as the process of the diffusion and migration of the adatoms.

China Spallation Neutron Source: Accelerator Design Iterations and R&D Status

J. Wei,C.-D. Deng,C.-H. Wang,C.-T. Shi,H. Sun,H.-F. Ouyang,H.-M. Qu,H.-Y. Dong,J. Li,J. Zhang,J.-S. Cao,J.-Y. Tang,L. Dong,L.-L. Wang,Q. Qin,Q.-B. Wang,S. Wang,S.-N. Fu,S.-X Fang,T. -G. Xu,W. Kang,Y.- 한국물리학회 2007 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.50 No.I

The China Spallation Neutron Source (CSNS) is a high-power, accelerator-based project currently under preparation. The accelerator complex consists of an H$^-$ ion source, an H$^-$ linac, a rapid-cycling proton synchrotron, and the transport lines. During the past year, the design of most accelerator systems went through major iterations, and initial research and developments was started on the prototyping of several key components.

Deoxynivalenol exposure induces autophagy/apoptosis and epigenetic modification changes during porcine oocyte maturation

Han, J.,Wang, Q.C.,Zhu, C.C.,Liu, J.,Zhang, Y.,Cui, X.S.,Kim, N.H.,Sun, S.C. Academic Press 2016 Toxicology and applied pharmacology Vol.300 No.-

Deoxynivalenol (DON) is a widespread trichothecene mycotoxin which contaminates agricultural staples and elicits a complex spectrum of toxic effects on humans and animals. It has been shown that DON impairs oocyte maturation, reproductive function and causes abnormal fetal development in mammals; however, the mechanisms remain unclear. In the present study, we investigate the possible reasons of the toxic effects of DON on porcine oocytes. Our results showed that DON significantly inhibited porcine oocyte maturation and disrupted meiotic spindle by reducing p-MAPK protein level, which caused retardation of cell cycle progression. In addition, up-regulated LC3 protein expression and aberrant Lamp2, LC3 and mTOR mRNA levels were observed with DON exposure, together with Annexin V-FITC staining assay analysis, these results indicated that DON treatment induced autophagy/apoptosis in porcine oocytes. We also showed that DON exposure increased DNA methylation level in porcine oocytes through altering DNMT3A mRNA levels. Histone methylation levels were also changed showing with increased H3K27me3 and H3K4me2 protein levels, and mRNA levels of their relative methyltransferase genes, indicating that epigenetic modifications were affected. Taken together, our results suggested that DON exposure reduced porcine oocytes maturation capability through affecting cytoskeletal dynamics, cell cycle, autophagy/apoptosis and epigenetic modifications.

HT-2 toxin affects development of porcine parthenotes by altering DNA and histone methylation in oocytes matured in vitro

Zhang, Y.,Jia, R.X.,Pan, M.H.,Lu, Y.,Cui, X.S.,Kim, N.H.,Sun, S.C. Butterworths, etc 2017 Theriogenology Vol. No.

T-2 toxin is a type A mycotoxin produced by various Fusarium species, while HT-2 toxin is a major metabolite of T-2 toxin. Both T-2 toxin and HT-2 toxin are known to have deleterious effects on animals. Our previous work showed that HT-2 treatment caused the failure of porcine oocyte maturation. In this study, we reported that HT-2 also affected porcine embryo development. In HT-2 toxin treated group, all the percentages of embryos in 2-cell, 4-cell and blastocyst stage were significantly lower compared with those in control groups. We then explored the causes from the epigenetic modification aspect of the oocytes. The analysis of fluorescence intensity showed that 5-methyl cytosine (5 mC) level was increased after exposure to HT-2 toxin in porcine oocytes, indicating that the general DNA methylation level increased in the treated porcine oocytes. In addition, histone modifications were also affected, since our results showed that H3K4me2 and H3K9me2 levels were increased in the oocytes from HT-2-treated group. Therefore, our results indicated that HT-2 toxin decreased porcine embryo developmental competence through altering the epigenetic modifications of oocytes.

A prospective multicentre phase II study of cisplatin and weekly docetaxel as first-line treatment for recurrent or metastatic nasopharyngeal cancer (KCSG HN07-01)

Korean Cancer Study Group,Ji, J.H.,Yun, T.,Kim, S.B.,Kang, J.H.,Park, J.C.,Cho, I.S.,Sohn, C.H.,Heo, D.S.,Jang, J.S.,Shin, S.W.,Hwang, D.W.,Sun, J.M.,Park, K.,Ahn, M.J. Pergamon Press 2012 European journal of cancer Vol.48 No.17

Background: The purpose of this phase II study was to determine the efficacy and toxicity of cisplatin and weekly docetaxel combination chemotherapy as a first-line treatment in patients with recurrent or metastatic nasopharyngeal cancer. Patients and Methods: Recurrent or metastatic nasopharyngeal cancer patients were enrolled and received a combination of weekly docetaxel (35mg/m<SUP>2</SUP> on Day1 and Day8) and cisplatin (70mg/m<SUP>2</SUP> D1) every 21days, for up to a maximum of 6 cycles. The primary endpoint was objective response rate, and the secondary endpoints included toxicity of combination chemotherapy, progression-free survival, overall survival and 1-year survival rate. Results: In total, 47 patients were enrolled and analysed, and 46 patients (97.9%) completed the planned protocol. In an intent-to-treat analysis, 6 patients (12.8%) achieved complete response (CR) and 27 patients (57.4%) showed partial response (PR), with an objective response rate of 70.2%. The median progression-free survival and overall survival were 9.6months (95% C.I. 5.7-13.5months) and 28.5months (95% C.I. 16.9-40.1months), respectively, and the 1-year survival rate was 89.9%. The common grade 3 adverse events were stomatitis (1.2%), neutropenia (0.8%), anaemia (0.8%), infection (0.8%) and diarrhoea (0.8%). Grade 4 adverse events were not observed in this study. Conclusions: The combination chemotherapy of cisplatin and weekly docetaxel is highly effective and shows favourable toxicity as a first-line chemotherapy in patients with recurrent or metastatic nasopharyngeal cancer.

Modification of argon impurity transport by electron cyclotron heating in KSTAR H-mode plasmas

Hong, Joohwan,Henderson, S.S.,Kim, Kimin,Seon, C.R.,Song, Inwoo,Lee, H.Y.,Jang, Juhyeok,Park, Jae Sun,Lee, S.G.,Lee, J.H.,Lee, Seung Hun,Hong, Suk-Ho,Choe, Wonho International Atomic Energy Agency 2017 Nuclear fusion Vol.57 No.3

<P>Experiments with a small amount of Ar gas injection as a trace impurity were conducted in the Korea Superconducting Tokamak Advanced Research (KSTAR) H-mode plasma (<img ALIGN='MIDDLE' ALT='${{B}_{\text{T}}}$ ' SRC='http://ej.iop.org/images/0029-5515/57/3/036028/nfaa5333ieqn001.gif'/>  =  2.8 T, <img ALIGN='MIDDLE' ALT='${{I}_{\text{P}}}$ ' SRC='http://ej.iop.org/images/0029-5515/57/3/036028/nfaa5333ieqn002.gif'/>  =  0.6 MA, and <img ALIGN='MIDDLE' ALT='${{P}_{\text{NBI}}}$ ' SRC='http://ej.iop.org/images/0029-5515/57/3/036028/nfaa5333ieqn003.gif'/>  =  4.0 MW). 170 GHz electron cyclotron resonance heating (ECH) at 600 and 800 kW was focused along the mid-plane with a fixed major radial position of <img ALIGN='MIDDLE' ALT='$R$ ' SRC='http://ej.iop.org/images/0029-5515/57/3/036028/nfaa5333ieqn004.gif'/>  =  1.66 m. The emissivity of the Ar<SUP>16+</SUP> (3.949 <img ALIGN='MIDDLE' ALT='${\mathring{\text{A}}}$ ' SRC='http://ej.iop.org/images/0029-5515/57/3/036028/nfaa5333ieqn005.gif'/>) and Ar<SUP>15+</SUP> (353.860 <img ALIGN='MIDDLE' ALT='${\mathring{\text{A}}}$ ' SRC='http://ej.iop.org/images/0029-5515/57/3/036028/nfaa5333ieqn006.gif'/>) spectral lines were measured by x-ray imaging crystal spectroscopy (XICS) and a vacuum UV (VUV) spectrometer, respectively. ECH reduces the peak Ar<SUP>15+</SUP> emission and increases the Ar<SUP>16+</SUP> emission, an effect largest with 800 kW. The ADAS-SANCO impurity transport code was used to evaluate the Ar transport coefficients. It was found that the inward convective velocity found in the plasma core without ECH was decreased with ECH, while diffusion remained approximately constant resulting in a less-peaked Ar density profile. Theoretical results from the NEO code suggest that neoclassical transport is not responsible for the change in transport, while the microstability analysis using GKW predicts a dominant ITG mode during both ECH and non-ECH plasmas.</P>

Phosphorylation of c-Jun in Avian and Mammalian Motoneurons In Vivo during Programmed Cell Death: An Early Reversible Event in the Apoptotic Cascade

Sun, W.,Gould, T. W.,Newbern, J.,Milligan, C.,Choi, S. Y.,Kim, H.,Oppenheim, R. W. OXFORD UNIVERSITY PRESS 2005 The Journal of neuroscience Vol.25 No.23

KITENIN increases invasion and migration of mouse squamous cancer cells and promotes pulmonary metastasis in a mouse squamous tumor model

Lee, J.K.,Bae, J.A.,Sun, E.G.,Kim, H.D.,Yoon, T.M.,Kim, K.,Lee, J.H.,Lim, S.C.,Kim, K.K. North-Holland Pub ; Elsevier Science Ltd 2009 FEBS letters Vol.583 No.4

KAI1 C-terminal interacting tetraspanin (KITENIN) is reported to promote metastasis in mouse colon cancer models. We investigated the role of KITENIN on the progression of squamous cell carcinoma (SCC). In a preliminary clinical study using resected tissues from head and neck SCC patients, KITENIN was highly expressed in tumors and metastatic lymph nodes, while KAI1 was more increased in adjacent mucosa than in tumor. KITENIN-transfected mouse squamous cancer (SCC VII/KITENIN) cells showed significantly higher invasion, migration, and proliferation than empty vector-transfected cells. In syngeneic mouse squamous tumor models, more increased tumor volume and enhanced lung metastasis were found in SCC VII/KITENIN cells-injected mice. Thus, KITENIN increases invasion and migration of squamous cancer cells and thereby promotes distant metastasis in mouse squamous tumor models.