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>

Covalent attachment of chiral alkaloids onto silicon surfaces

H. Wang,H.L. Zhang,Y. Guo,F.Y. Qiao,Q.Y. Sun 한국물리학회 2007 Current Applied Physics Vol.7 No.s1

In this work, we report the covalent attachment of a chiral molecule onto a hydrogen-terminated Si(SiH) surface by using an extre-mely mild approach. Cinchonine, a chiral alkaloid was self-assembled onto a SiH surface via a photochemistry method at room tem-perature. The self-assembled monolayers (SAMs) obtained were characterized by means of ellipsometry, XPS and wettability studies.The lm formation kinetics was monitored by ellipsometry and XPS, which indicated that a full monolayer was formed within 15 h.

Azasiline-based thermally activated delayed fluorescence emitters for blue organic light emitting diodes

Sun, J.,Baek, J.,Kim, K. H.,Huh, J. S.,Kwon, S. K.,Kim, Y. H.,Kim, J. J. Royal Society of Chemistry 2017 Journal of Materials Chemistry C Vol.5 No.5

<P>Recently, the azasiline unit was introduced as a donor in thermally activated delayed fluorescence (TADF) emitters to realize efficient blue fluorescence from organic light emitting diodes (OLEDs). Utilizing the azasiline unit DTPPDDA in the formation of donor-connector-acceptor (D-C-A) materials resulted in deep blue emission with a Commission Internationale de l'Eclairage (CIE) coordinate of (0.151, 0.087), close to the blue standard of the National Television System Committee (NTSC) of (0.140, 0.080) with 4.7% External Quantum Efficiency (EQE). In the donor-acceptor-donor (D-A-D) type materials of BDAPM and SPDDA, carbonyl and sulfone units were used as the acceptors, respectively. The sulfonyl unit contributed to a large twist of the molecular structure while the carbonyl unit led to a small twist of the molecular structure. As a result, the blue fluorescent OLEDs containing BDAPM and SPDDA demonstrated 11.4% and 2.3% EQEs with CIE Y-values of 0.310 and 0.107, respectively.</P>

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.

Microstructural Stability and Creep Performance of a Novel Low-Cost Single Crystal Superalloy

Z. H. Tan,X. G. Wang,Y. L. Du,Y. M. Li,Y. H. Yang,J. L. Liu,J. D. Liu,J. G. Li,Y. Z. Zhou,X. F. Sun 대한금속·재료학회 2022 METALS AND MATERIALS International Vol.28 No.7

The increasing pursuit of advanced aero-engines with lower ratio between the cost and performance has greatly promotedthe demanding of single crystal superalloys characterized by low cost and outstanding temperature capability. In this study,a novel low-cost single crystal superalloy was designed and the creep tests as well as micro-characterization were carried outon the experimental alloy. The results illustrated that the novel single crystal alloy exhibited an ideal microstructural stabilitywithout precipitating TCP phases, after long-term thermal exposure at the ultimate service temperature of third generationsingle crystal superalloys. Moreover, the experimental alloy with only 3 wt% Re addition demonstrated remarkable creepresistance and maintained a very low minimum creep rate at 1100 °C/137 MPa and 1120 °C/137 MPa, while the accumulationand coalescence of micro-pores had eventually led to the alloy fracture. Apart from that, the compact interfacial dislocationnetworks the 2nd γ′ phase were observed after high-temperature creep rupture, and the typical a < 010 > superdislocationswith relatively poor mobility was found at 1120 °C. At 760 °C/800 MPa, both the minimum creep velocity and entire creepstain was increased evidently, however, the ultimate creep rupture life of the alloy had still reached 200 h. The correspondingdeformation mechanism was identified as the combination of superdislocation pairs shearing and a/3 < 121 > partial dislocationcutting the γ′ phase with a SISF being generated. In general, the novel single crystal alloy characterized by remarkablemechanical properties and cost reduction possesses a great potential for future application in the advanced aircraft engines.

Cowpea bruchid midgut transcriptome response to a soybean cystatin – costs and benefits of counter-defence

Chi, Y. H.,Salzman, R. A.,Balfe, S.,Ahn, J.-E.,Sun, W.,Moon, J.,Yun, D.-J.,Lee, S. Y.,Higgins, T. J. V.,Pittendrigh, B.,Murdock, L. L.,Zhu-Salzman, K. Blackwell Publishing Ltd 2009 INSECT MOLECULAR BIOLOGY Vol.18 No.1

<P>Abstract</P><P>The insect digestive system is the first line of defence protecting cells and tissues of the body from a broad spectrum of toxins and antinutritional factors in its food. To gain insight into the nature and breadth of genes involved in adaptation to dietary challenge, a collection of 20 352 cDNAs was prepared from the midgut tissue of cowpea bruchid larvae (<I>Callosobruchus maculatus</I>) fed on regular diet and diets containing antinutritional compounds. Transcript responses of the larvae to dietary soybean cystatin (scN) were analysed using cDNA microarrays, followed by quantitative real-time PCR (RT-PCR) confirmation with selected genes. The midgut transcript profile of insects fed a sustained sublethal scN dose over the larval life was compared with that of insects treated with an acute high dose of scN for 24 h. A total of 1756 scN-responsive cDNAs was sequenced; these clustered into 967 contigs, of which 653 were singletons. Many contigs (451) did not show homology with known genes, or had homology only with genes of unknown function in a B<SMALL>LAST</SMALL> search. The identified differentially regulated sequences encoded proteins presumptively involved in metabolism, structure, development, signalling, defence and stress response. Expression patterns of some scN-responsive genes were consistent in each larval stage, whereas others exhibited developmental stage-specificity. Acute (24 h), high level exposure to dietary scN caused altered expression of a set of genes partially overlapping with the transcript profile seen under chronic lower level exposure. Protein and carbohydrate hydrolases were generally up-regulated by scN whereas structural, defence and stress-related genes were largely down-regulated. These results show that insects actively mobilize genomic resources in the alimentary tract to mitigate the impact of a digestive protease inhibitor. The enhanced or restored digestibility that may result is possibly crucial for insect survival, yet may be bought at the cost of weakened response to other stresses.</P>

Distinct clinical courses according to presenting phenotypes and their correlations to <i>ATP7B</i> mutations in a large Wilson's disease cohort

Lee, Beom H.,Kim, Joo H.,Lee, Sun Y.,Jin, Hye Y.,Kim, Kwi‐,Joo,Lee, Jin‐,Joo,Park, Jung‐,Young,Kim, Gu‐,Hwan,Choi, Jin‐,Ho,Kim, Kyung M.,Yoo, Han‐,Wook Blackwell Publishing Ltd 2011 Liver International Vol.31 No.6

<P><B>Abstract</B></P><P><B>Introduction and aims: </B> Wide phenotypic and genotypic heterogeneities in Wilson's disease (WD) have been reported, hampering the study of their correlations. The goal of this study was to identify the factors related to these diversities.</P><P><B>Methods: </B> Clinical courses and molecular genetic characteristics were analysed in 237 unrelated Korean WD families. The average follow‐up period was 8.2 ± 5.8 years.</P><P><B>Results: </B> Presenting phenotypes were classified as H1 (12.2%), H2 (42.4%), N1 (21.6%), N2 (0.4%), NX (0.4%), presymptomatic (22.4%) and other (0.4%), modifying the guidelines by Ferenci and colleagues. Age at presentation was youngest and cirrhosis was rarest in the presymptomatic group. Decompensated cirrhosis was the highest in the H1 group. Favourable outcome was rarest in the N1 group. Forty‐seven (11 novel) <I>ATP7B</I> mutations were identified in 85% of the 474 alleles. Multiplex ligation‐dependent probe amplification assays in <I>ATP7B</I> and analyses of <I>ATOX1</I> and <I>COMMD1</I> genes identified no additional mutations. Yeast complementation assays demonstrated functional perturbation of the seven novel missense mutants. Five major mutations, p.Arg778Leu, p.Ala874Val, p.Asn1270Ser, p.Lys838SerfsX35 and p.Leu1083Phe, accounted for 63% of the alleles. H1 was more common, age at presentation was younger and N1+N2+NX tended to be less common in patients with nonsense, frame shifting or splicing mutations than in those with missense mutations alone. Patients with both mutations in the transduction (Td) or the ATP hinge domain showed presymptomatic or hepatic manifestations but no neurological manifestation.</P><P><B>Conclusions: </B> The presenting phenotype strongly affects the clinical outcome of WD, and is related to the <I>ATP7B</I> mutation type and location, providing an evidence for genotype–phenotype correlations in WD.</P>

원발성 간암에서 PIVKA-II 및 Lens Culinaris Agglutinin-A 반응성 Alpha-fetoprotein(AFP-L3)의 임상적 유용성

배시현,박두호,양진모,박영민,차상복,최종영,성광용,조세현,정규원,선희식,김부성,최상욱,변병훈,한남익 대한간학회 2000 Clinical and Molecular Hepatology(대한간학회지) Vol.6 No.2

Background/Aims: Des-γ-carboxy prothrombin(DCP), a protein induced by vitamin K absence or antagonist-II(PIVKA-II), and Lens culinaris agglutinin-A reactive AFP-L3 have been reported to be useful markers for the diagnosis of hepatocellular carcinoma (HCC). In the present study, both the PIVKA-II and AFP-L3 were analyzed and compared with a conventional AFP to determine its usefulness, specificity and sensitivity in the diagnosis of HCC. Methods: Sera were collected from 108 patients consisting of 17 patients with chronic hepatitis, 22 patients with liver cirrhosis and 69 patients with HCC. The AFP-L3 was determined by an lectin affinity electrophoresis coupled with an antibody-affinity blotting. Level of DCP was measured by an enzyme immunoassay with an anti-DCP monoclonal antibody. Results: The sensitivity and specificity of PIVKA-II and AFP L3 were 49.3% and 89.5%, and 32.5% and 85.7%, respectively. No significant correlation was found between the PIVKA-II or AFP L3 and serum AFP. No correlation was found etween the PIVKA-II or AFP L3 and the characteristics of HCC. Conclusion: The determination of plasma DCP and AFP L3 levels combined with AFP levels may be useful especially for the differential diagnosis between HCC and chronic liver diseases without HCC.(Korean J HepatoBackground/Aims: Des-γ-carboxy prothrombin(DCP), a protein induced by vitamin K absence or antagonist-II(PIVKA-II), and Lens culinaris agglutinin-A reactive AFP-L3 have been reported to be useful markers for the diagnosis of hepatocellular carcinoma (HCC). In the present study, both the PIVKA-II and AFP-L3 were analyzed and compared with a conventional AFP to determine its usefulness, specificity and sensitivity in the diagnosis of HCC. Methods: Sera were collected from 108 patients consisting of 17 patients with chronic hepatitis, 22 patients with liver cirrhosis and 69 patients with HCC. The AFP-L3 was determined by an lectin affinity electrophoresis coupled with an antibody-affinity blotting. Level of DCP was measured by an enzyme immunoassay with an anti-DCP monoclonal antibody. Results: The sensitivity and specificity of PIVKA-II and AFP-L3 were 49.3% and 89.5%, and 32.5% and 85.7%, respectively. No significant correlation was found between the PIVKA-II or AFP-L3 and serum AFP. No correlation was found etween the PIVKA-II or AFP L3 and the characteristics of HCC. Conclusion: The determination of plasma DCP and AFP-L3 levels combined with AFP levels may be useful especially for the differential diagnosis between HCC and chronic liver diseases without HCC.(Korean J Hepatol 2000;6:205-214)l 2000;6:205-214)

Effect of Lansoprazole on 24 Hour Intragastric pH and Acid Secretion in Peptic Ulcer Patients and Healthy Volunteers

Na, J. S 大韓臨床藥理學會 1997 臨床藥理學會誌 Vol.5 No.1

칼슘급여수준· 급여방법·입자도·연령이 메추리의 진정이용칼슘가에 미치는 영향

김용식,선상수,명규호 ( Y . S . Kim,S . S . Sun,K . H . Myung ) 한국축산학회 1985 한국축산학회지 Vol.27 No.6

The relationships between calcium input level and excreta calcium, and true available calcium (TAC) values were Y=3.21 × 10^(-4)x²+ 0.52X-0.48 (r=0.9832^(**) and Y=-6.21 × 10^(-3)X² -0.03 (r=0.9738^(**)) respectively. The TAC values of limestone and oyster shell were the highest in the 40-80 mesh as 74.67%, and the lowest in the 10-30 mesh as 68.2% and 61.01% respectively. Excreted calcium from fed birds were significantly increased (p$lt;0.05) as the age of birds increased, however, excreted calcium from unfed birds were almost same in all the age of birds. The TAC value of calcium carbonate was the highest in that of 16 weeks old bird as 99.42±1.32%. The relationships between age of bird and excreta calcium, and TAC value were Y=0.578x-0.0475 (r=0.9960^(**)) and Y=-0.129X+100.0425 (r=-0.9850^(**)) respectively.