Electrocatalytic activity of chemically deposited Cu_xS thin film for counter electrode in quantum dots-sensitized solar cells

Lim, I.,Lee, D.Y.,Patil, S.A.,Shrestha, N.K.,Kang, S.H.,Nah, Y.C.,Lee, W.,Han, S.H. Elsevier Science Publishers 2014 Materials chemistry and physics Vol.148 No.3

The compact (c-Cu<SUB>x</SUB>S) and the porous (p-Cu<SUB>x</SUB>S) with particle decorated films of coppers-ulfidearesynthesized using a chemical bath deposition technique, and the films are characterized using electrochemical techniques. In addition, the chemically deposited Cu<SUB>x</SUB>S films are investigated as a counter electrode in quantum dots-sensitized solar cells (QSSCs). The available redox active reaction sites of the p-Cu<SUB>x</SUB>S film are found to be 57.9% higher than those available in the c-Cu<SUB>x</SUB>S film. From the electrochemical impedance spectroscopy, the effective diffusion coefficients of the polysulfide electrolyte in the c-Cu<SUB>x</SUB>S and p-Cu<SUB>x</SUB>S films are estimated to be 3.67 x 10<SUP>-5</SUP> and 6.35 x 10<SUP>-5</SUP> cm<SUP>2</SUP> s<SUP>-1</SUP>, respectively. These results can be ascribed to the improvement in the available redox active reaction sites and the electrocatalytic activity of the Cu<SUB>x</SUB>S counter electrode. As compared to the c-Cu<SUB>x</SUB>S film, the p-Cu<SUB>x</SUB>S film as a counter electrode exhibits an enhanced photovoltaic performance of the QSSCs with the power conversion efficiency of 3.17%, short-circuit current of 11.89 mA c<SUP>-</SUP>m<SUP>2</SUP>, open-circuit voltage of 0.50 V, and fill factor of 53.29. The improved performance of the QSSCs is ascribed to the improvements on the available redox active reaction sites, electrocatalytic activity and the diffusion coefficients, which are directly related to the surface morphology of the sulfide films.

Regulation of cancer cell death by a novel compound, C604, in a c-Myc-overexpressing cellular environment

Jo, M.J.,Paek, A.R.,Choi, J.S.,Ok, C.Y.,Jeong, K.C.,Lim, J.H.,Kim, S.H.,You, H.J. North-Holland ; Elsevier Science Ltd 2015 european journal of pharmacology Vol.769 No.-

<P>The proto-oncogene c-Myc has been implicated in a variety of cellular processes, such as proliferation, differentiation and apoptosis. Several c-Myc targets have been studied; however, selective regulation of c-Myc is not easy in cancer cells. Herein, we attempt to identify chemical compounds that induce cell death in c-Myc-overexpressing cells (STF-cMyc and STF-Control) by conducting MTS assays on approximately 4000 chemical compounds. One compound, C604, induced cell death in STF-cMyc cells but not STF-Control cells. Apoptotic proteins, including caspase-3 and poly(ADP-ribose) polymerase (PAPP), were cleaved in C604-treated STF-cMyc cells. In addition, 5W620, HCT116 and NCI-H23 cells, which exhibit higher basal levels of c-Myc, underwent apoptotic cell death in response to C604, suggesting a role for C604 as an inducer of apoptosis in cancer cells with c-Myc amplification. C604 induced cell cycle arrest at the G2/M phase in cells, which was not affected by apoptotic inhibitors. Interestingly, C604 induced accumulation of c-Myc and Cdc25A proteins. In summary, a chemical compound was identified that may induce cell death in cancer cells with c-Myc amplification specifically through an apoptotic pathway. (C) 2015 Elsevier B.V. All rights reserved.</P>

Holocene environmental change at the southern coast of Korea based on organic carbon isotope (δ¹³C) and C/S ratios

Lim, J.,Lee, J.Y.,Kim, J.C.,Hong, S.S.,Yang, D.Y. Pergamon Press 2015 QUATERNARY INTERNATIONAL Vol.384 No.-

<P>To trace the environmental change that occurred at a coastal area during the Holocene, we performed radiocarbon dating and geochemical analyses using sedimentary cores recovered from the Beolgyo tidal flats on the south coast of Korea. The delta C-13 values of total organic carbon (TOC), which represent relative inputs of terrestrial (or freshwater) and marine organic sources, revealed a long-term increasing trend from -27.5 to -21.7 parts per thousand during the period between 10,000 and 3000 cal BP, suggesting an evolutionary series of fluvial-dominant to marine-dominant environments, coupled with weakened summer monsoon intensity. From 3000 cal BP to the present, the delta C-13(TOC) decreased gradually from -21.7 to -24 parts per thousand, indicating enhancement of freshwater input during this time. The observed long-term environmental change was divided into six stages based on the averages of the total sulfur content (TS%) and the organic carbon to sulfur ratio (C/S), proxies for paleosalinity. On multi-centennial to millennial timescales, higher C/S ratios and lower TS% were linked to higher delta C-13(TOC) values, indicating strong freshwater input at Stage 2 (similar to 8300-7400 cal BP), Stage 4 (similar to 4500-3300 cal BP), and Stage 6 (similar to 1100 cal BP to present). Strong freshwater discharge events synchronously occurred at 4300 cal BP and 3600 cal BP along the south coast of Korea. Further testing should be carried out in other East Asian coastal areas. This study suggests that sedimentary delta C-13(TOC) values and C/S ratios can be used in Asian coastal regions to trace past freshwater input events and summer monsoon intensity during relatively stable sea level periods (e.g., the middle to late Holocene). (C) 2015 Elsevier Ltd and INQUA. All rights reserved.</P>

9주간 복합운동 프로그램이 댄스스포츠 선수인 여고생의 체력, 혈액성분, 산화적 스트레스 및 항산화 능력에 미치는 영향

임채성 ( C. S. Lim ),지용석 ( Y. S. Ji ),장창현 ( C. H. Jang ) 한국운동생리학회(구 한국운동과학회) 2011 운동과학 Vol.20 No.3

임채성, 지용석, 장창현. 9주간 복합운동 프로그램이 댄스스포츠 선수인 여고생의 체력, 혈액성분, 산화적 스트레스 및 항산화 능력에 미치는 영향. 운동과학, 제20권 제3호. 227-238, 2011. 본 연구의 목적은 9주간의 DS+CT(댄스스포츠+복합운동) 집단이 댄스스포츠 선수인 여고생의 체력, 혈액성분, 산화적 스트레스 및 항산화 능력에 미치는 영향을 규명하는 것이었다. 연구 대상은 현재 댄스스포츠 선수로서 과거에 규칙적인 복합운동 프로그램에 참여한 경험이 없는 여고생 16명과 규칙적인 운동을 하지 않는 여고생 8명으로 구성하였다. DS+CT(댄스스포츠+복합운동) 집단의 대상자 8명은 일일 60분, 주 3회, 9주간의 복합운동 프로그램에 참여하였고, DS(댄스스포츠)집단과 C(통제)집단 16명은 동일한 처치 기간 동안 평소 생활방식을 그대로 유지하였다. 처치 전과 후에 체력, 혈액성분과 항산화 스트레스 및 능력을 비교하였다. 본 연구의 결과는 다음과 같다. 1. 체력과 관련된 변인은 DS+CT 집단의 악력, 근지구력, 유연성, 민첩성, 순발력의 변화가 유의한 차이가 있었고(p<.05, p<.01), DS집단과 C집단에서는 체력과 관련된 모든 변인에서 유의한 차이가 나타나지 않았다. 2. 혈액성분과 관련된 변인은 DS+CT 집단은 HDL-C, DS집단은 TC가 유의한 차이를 보였으며(p<.05), C집단은 유의한 차이가 나타나지 않았다. 3. 산화적 스트레스 및 항산화 능력과 관련된 변인은 DS+CT집단에서 산화적 스트레스가 감소하는 경향을 보였고, 항산화 능력은 유의하게 증가되었다(p<.05). DS집단과 C 집단은 산화적 스트레스와 항산화 능력 모두에서 유의한 변화가 나타나지 않았다. 이상의 결과를 종합해 보면, 9주간의 복합운동 트레이닝 프로그램이 댄스스포츠 선수인 여고생의 체력, 혈액성분과 산화적 스트레스 및 항산화 능력에 긍정적인 영향을 미치는 것으로 결론지을 수 있다. 더 의미 있는 연구를 위해서는 향후 보다 장기간의 트레이닝이 수반되는 연구가 필요하다고 생각된다. The purpose of this study was to investigate the effects of physical fitness, blood component, oxidant stress and antioxidant capacity to 9-weeks complex training in girls high school dance sport players. This was performed by analyzing 16 female high school dance sport athletes and 8 ordinary female high school students who were divided into 3 groups DS+CT (dance sport+complex training), DS (dance sport), C (control) of which each composed of 8 students. The results of the study can be summarized as follows: 1. Physical fitness showed that muscular strength, muscular endurance, flexibility, agility, power increased after the exercise from the group of DS+CT (p<.05, p<.01). DS and C did not show any significant difference. 2. Blood component showed that HDL-C increased after the exercise from the group of DS+CT (p<.05). DS showed significant difference in TC (p<.05). C (control croup) did not show any significant difference. 3. Oxidant stress and antioxidant capacity showed that antioxidant capacity increased after the exercise from the group of DS+CT (p<.05). DS and C did not show any significant difference. In conclusions, this study suggests that the 9 weeks combined exercise program can improve physical fitness, blood component, oxidant stress and antioxidant capacity in girls high school dance sport players.

Somatic Mutations in TSC1 and TSC2 Cause Focal Cortical Dysplasia

Lim, J.S.,Gopalappa, R.,Kim, S.H.,Ramakrishna, S.,Lee, M.,Kim, W.i.,Kim, J.,Park, S.M.,Lee, J.,Oh, J.H.,Kim, H.D.,Park, C.H.,Lee, J.S.,Kim, S.,Kim, D.S.,Han, J.M.,Kang, H.C.,Kim, H.(.,Lee, J.H. University of Chicago Press [etc.] 2017 American journal of human genetics Vol.100 No.3

<P>Focal cortical dysplasia (FCD) is a major cause of the sporadic form of intractable focal epilepsies that require surgical treatment. It has recently been reported that brain somatic mutations in MTOR account for 15%-25% of FCD type II (FCDII), characterized by cortical dyslamination and dysmorphic neurons. However, the genetic etiologies of FCDII-affected individuals who lack the MTOR mutation remain unclear. Here, we performed deep hybrid capture and amplicon sequencing (read depth of 100 x-20,012 x) of five important mTOR pathway genes-PIK3CA, PIK3R2, AKT3, TSC1, and TSC2-by using paired brain and saliva samples from 40 FCDII individuals negative for MTOR mutations. We found that 5 of 40 individuals (12.5%) had brain somatic mutations in TSC1 (c.64C>T [p.Arg22Trp] and c.610C>T [p.Arg204Cys]) and TSC2 (c.4639G>A [p.Va11547I1e]), and these results were reproducible on two different sequencing platforms. All identified mutations induced hyperactivation of the mTOR pathway by disrupting the formation or function of the TSC1TSC2 complex. Furthermore, in utero CRISPR-Cas9-mediated genome editing of Tsc1 or Tsc2 induced the development of spontaneous behavioral seizures, as well as cytomegalic neurons and cortical dyslamination. These results show that brain somatic mutations in TSC1 and TSC2 cause FCD and that in utero application of the CRISPR-Cas9 system is useful for generating neurodevelopmental disease models of somatic mutations in the brain.</P>

Hydrolytic properties of a thermostable &agr;-<small>L</small>-arabinofuranosidase from <i>Caldicellulosiruptor saccharolyticus</i>

Lim, Y.-R.,Yoon, R.-Y.,Seo, E.-S.,Kim, Y.-S.,Park, C.-S.,Oh, D.-K. Blackwell Publishing Ltd 2010 Journal of Applied Microbiology Vol.109 No.4

<P>Abstract</P><P>Aims: </P><P>To characterize of a thermostable recombinant &agr;-<SMALL>L</SMALL>-arabinofuranosidase from <I>Caldicellulosiruptor saccharolyticus</I> for the hydrolysis of arabino-oligosaccharides to <SMALL>L</SMALL>-arabinose.</P><P>Methods and Results: </P><P>A recombinant &agr;-<SMALL>L</SMALL>-arabinofuranosidase from <I>C. saccharolyticus</I> was purified by heat treatment and Hi-Trap anion exchange chromatography with a specific activity of 28·2 U mg<SUP>−1</SUP>. The native enzyme was a 58-kDa octamer with a molecular mass of 460 kDa, as measured by gel filtration. The catalytic residues and consensus sequences of the glycoside hydrolase 51 family of &agr;-<SMALL>L</SMALL>-arabinofuranosidases were completely conserved in &agr;-<SMALL>L</SMALL>-arabinofuranosidase from <I>C. saccharolyticus</I>. The maximum enzyme activity was observed at pH 5·5 and 80°C with a half-life of 49 h at 75°C. Among aryl-glycoside substrates, the enzyme displayed activity only for <I>p</I>-nitrophenyl-&agr;-<SMALL>L</SMALL>-arabinofuranoside [maximum <I>k</I><SUB>cat</SUB>/<I>K</I><SUB>m</SUB> of 220 m(mol l<SUP>−1</SUP>)<SUP>−1</SUP> s<SUP>−1</SUP>] and <I>p</I>-nitrophenyl-&agr;-<SMALL>L</SMALL>-arabinopyranoside. This substrate specificity differs from those of other &agr;-<SMALL>L</SMALL>-arabinofuranosidases. In a 1 mmol l<SUP>−1</SUP> solution of each sugar, arabino-oligosaccharides with 2–5 monomer units were completely hydrolysed to <SMALL>L</SMALL>-arabinose within 13 h in the presence of 30 U ml<SUP>−1</SUP> of enzyme at 75°C.</P><P>Conclusions: </P><P>The novel substrate specificity and hydrolytic properties for arabino-oligosaccharides of &agr;-<SMALL>L</SMALL>-arabinofuranosidase from <I>C. saccharolyticus</I> demonstrate the potential in the commercial production of <SMALL>L</SMALL>-arabinose in concert with endoarabinanase and/or xylanase.</P><P>Significance and Impact of the Study: </P><P>The findings of this work contribute to the knowledge of hydrolytic properties for arabino-oligosaccharides performed by thermostable &agr;-<SMALL>L</SMALL>-arabinofuranosidase.</P>

T_c and J_c distribution in in situ processed MgB₂ bulk superconductors with/without C doping

Kim, C.J.,Kim, Y.J.,Lim, C.Y.,Jun, B.H.,Park, S.D.,Choo, K.N. The Korea Institute of Applied Superconductivity a 2014 한국초전도저온공학회논문지 Vol.16 No.2

Temperature dependence of magnetic moment (m-T) and the magnetization (M-H) at 5 K and 20 K of the in situ processed $MgB_2$ bulk pellets with/without carbon (C) doping were examined. The superconducting critical temperature ($T_c$), the superconducting transition width (${\delta}T$) and the critical current density ($J_c$) were estimated for ten test samples taken from the $MgB_2$ bulk pellets. The reliable m-T characteristics associated with the uniform $MgB_2$ formation were obtained for both $MgB_2$ pellets. The $T_cs$ and ${\delta}Ts$ of all test samples of the undoped $MgB_2$ were the same each other as 37.5 K and 1.5 K, respectively. The $T_cs$ and ${\delta}Ts$ of the C-doped $MgB_2$ were 36.5 K and 2.5 K, respectively. Unlike the m-T characteristics, there existed the difference among the M-H curves of the test samples, which might be caused by the microstructure variation. In spite of the slight $T_c$ decrease, the C doping was effective in enhancing the $J_c$ at 5 K.

Conversion of single-crystalline C₆₀ nanodisks and nanorods into graphitic nanostructures via hydrogen thermal annealing

Lim, H,Shin, H S,Song, H J,Choi, H C IOP Pub 2009 Nanotechnology Vol.20 No.14

<P>We have developed a process to convert C<SUB>60</SUB> nanostructures into graphitic nanostructures. Disk-shaped and wire-shaped C<SUB>60</SUB> nanostructures synthesized by the liquid–liquid interfacial precipitation method, the vapor–solid process, and solvent evaporation were successfully converted into graphitic structures by thermal annealing in hydrogen at 900 °C. Scanning electron and tunneling electron microscopic studies confirmed that the converted nanostructures were composed of multi-graphitic structures such as multi-walled carbon nanotubes, carbon nanofibers, and carbon onions. Fourier transform Raman spectroscopy and conductance measurements were carried out to further confirm the successful formation of graphitic layers. In the Raman spectra, the nanostructures converted from C<SUB>60</SUB> disks showed signature D, G, and G<SUP>′</SUP> bands of graphitic structures, while the A<SUB>g</SUB> mode (1469 cm<SUP>−1</SUP>) of the original C<SUB>60</SUB> molecule disappeared. C<SUB>60</SUB> nanowire devices fabricated for the conductance measurements of the converted structures showed dramatically decreased resistance (<I>R</I>≈100 kΩ) compared to the pristine C<SUB>60</SUB> wire (<I>R</I>>100 MΩ). Further manipulation of the reaction environment, including the gas and the annealing temperature, may reveal a new way to attain diverse graphitic nanostructures economically. </P>

COMP-Ang1 enhances DNA synthesis and cell cycle progression in human periodontal ligament cells via Tie2-mediated phosphorylation of PI3K/Akt and MAPKs

Lim, S. S.,Kook, S. H.,Lee, J. C. Springer Science + Business Media 2016 MOLECULAR AND CELLULAR BIOCHEMISTRY - Vol.416 No.1

<P>Recombinant COMP-Ang1, a chimera of angiopoietin-1 (Ang1), and a short coiled-coil domain of cartilage oligomeric matrix protein (COMP) can stimulate multiple cellular processes. Proliferative capacity of periodontal ligament (PDL) fibroblasts (PLFs) is important for maintaining PDL integrity and homeostasis. In this study, we explored whether exogenous COMP-Ang1 addition enhances proliferation of human PLFs and the cellular mechanisms therein. We initially isolated and characterized PLFs, where the cells showed highly positive staining for surface markers, CD90, CD105, and CD146. COMP-Ang1 treatment increased proliferation of PLFs by stimulating migration of cells into S and G(2)/M phases. This increase was coupled with decreased p21(Cip) and p27(Kip) levels and enhanced cyclin D-1, cyclin-dependent kinase (CDK) 2, and CDK4 induction. Transfection with si-Tie2 near completely blocked COMP-Ang1-stimulated cell cycle progression in PLFs. Tie2 knockdown also inhibited COMP-Ang1-induced phosphorylation of mitogen-activated protein kinases (MAPKs). In addition, COMP-Ang1-mediated activation of Akt and c-Jun was suppressed by treating each of pharmacological inhibitors specific to phosphoinositide 3-kinase (PI3K) (LY294002 and Wortmannin) or MAPKs (PD98059, SB203580, and SP600125). Similarly, COMP-Ang1-mediated increases in DNA synthesis and cyclin D-1 induction were prevented by treating inhibitor of MAPKs and PI3K or by c-Jun knockdown. These results suggest that COMP-Ang1 enhances survival and proliferation of human PLFs through the activation of Tie2-mediated signaling, where PI3K/Akt and MAPK-c-Jun signaling pathways act as downstream effectors. Collectively, COMP-Ang1 may be a useful as a stimulator of human PLFs and therefore improves PDL integrity and homeostasis.</P>

CTRP1 protects against diet-induced hyperglycemia by enhancing glycolysis and fatty acid oxidation

Han, S.,Park, J.S.,Lee, S.,Jeong, A.L.,Oh, K.S.,Ka, H.I.,Choi, H.J.,Son, W.C.,Lee, W.Y.,Oh, S.J.,Lim, J.S.,Lee, M.S.,Yang, Y. Butterworths ; Elsevier Science Ltd 2016 The Journal of nutritional biochemistry Vol.27 No.-

<P>Complement-C1q/tumor necrosis factor-alpha related protein 1 (CTRP1) is a 35-kDa glycoprotein that is secreted from various tissues. Although CTRP1 is highly increased in patients with type II diabetes and obesity, the metabolic roles of CTRP1 remain largely unknown. To unveil the physiological roles of CTRP1 in vivo, CTRP1 transgenic (TG) mice were challenged by a high-fat diet (HFD) and a high-sucrose drink (HS). Homeostatic model assessment-estimated insulin resistance values were decreased in HFD- or HS-fed CTRP1 TG mice compared with wild-type control mice. In this context, CTRP1 stimulated glucose uptake through the glucose transporter GLUT4 translocation to the plasma membrane and also increased glucose consumption by stimulating glycolysis. To analyze the roles of CTRP1 in lipid metabolism, acetyl-CoA carboxylase (ACC) and hormone-sensitive lipase levels were determined in CTRP1 TG mice, and the effect of CTRP1 on fatty acid oxidation was assessed in C2C12 myotubes. CTRP1 was found to inhibit ACC by phosphorylation and to stimulate fatty acid oxidation in C2C12 myotubes. Taken together, CTRP1 performs active catabolic roles in vivo. Therefore, CTRP1 seems to perform a defensive function against nutritional challenges. (C) 2015 Elsevier Inc. All rights reserved.</P>