Large-amplitude flapping of an inverted flag in a uniform steady flow – a vortex-induced vibration

Sader, John E.,Cossé,, Julia,Kim, Daegyoum,Fan, Boyu,Gharib, Morteza Cambridge University Press 2016 Journal of fluid mechanics Vol.793 No.-

<P>The dynamics of a cantilevered elastic sheet, with a uniform steady flow impinging on its clamped end, have been studied widely and provide insight into the stability of flags and biological phenomena. Recent measurements by Kim<I>et al.</I>(<I>J. Fluid Mech.</I>, vol. 736, 2013, R1) show that reversing the sheet’s orientation, with the flow impinging on its free edge, dramatically alters its dynamics. In contrast to the conventional flag, which exhibits (small-amplitude) flutter above a critical flow speed, the inverted flag displays large-amplitude flapping over a finite band of flow speeds. The physical mechanisms giving rise to this flapping phenomenon are currently unknown. In this article, we use a combination of mathematical theory, scaling analysis and measurement to establish that this large-amplitude flapping motion is a vortex-induced vibration. Onset of flapping is shown mathematically to be due to divergence instability, verifying previous speculation based on a two-point measurement. Reducing the sheet’s aspect ratio (height/length) increases the critical flow speed for divergence and ultimately eliminates flapping. The flapping motion is associated with a separated flow – detailed measurements and scaling analysis show that it exhibits the required features of a vortex-induced vibration. Flapping is found to be periodic predominantly, with a transition to chaos as flow speed increases. Cessation of flapping occurs at higher speeds – increased damping reduces the flow speed range where flapping is observed, as required. These findings have implications for leaf motion and other biological processes, such as the dynamics of hair follicles, because they also can present an inverted-flag configuration.</P>

BEZ235 (PIK3/mTOR inhibitor) Overcomes Pazopanib Resistance in Patient-Derived Refractory Soft Tissue Sarcoma Cells

Kim, Hee Kyung,Kim, Sun Young,Lee, Su Jin,Kang, Mihyeon,Kim, Seung Tae,Jang, Jiryeon,Rath, Oliver,Schueler, Julia,Lee, Dong Woo,Park, Woong Yang,Kim, Sung Joo,Park, Se Hoon,Lee, Jeeyun Neoplasia Press 2016 Translational oncology Vol.9 No.3

<P><I>BACKGROUND:</I> Although pazopanib treatment has become the standard chemotherapy in salvage setting for metastatic sarcoma patients, most patients progress after pazopanib treatment in 4 to 6 months. After failure to pazopanib, patients have limited options for treatment. Therefore, subsequent therapy in patients who failed to pazopanib is urgently needed and the use of patient derived cells or patient derived tumors for accompanying testing with various pharmacological inhibitors could offer additional treatment options for these patients. <I>METHODS:</I> Patient derived tumor cells were collected from ascites at the time of progression to pazopanib and a 13-drug panel was tested for drug sensitivity. We confirmed the results using <I>in vitro</I> cell viability assay and immunoblot assay. We also performed the genomic profiling of PDX model. <I>RESULTS:</I> The growth of patient derived tumor cells was significantly reduced by exposure to 1.0 μM AZD2014 compared with control (control versus AZD2014, mean growth = 100.0% vs 16.04%, difference = 83.96%, 95% CI = 70.01% to 97.92%, <I>P</I> = .0435). Similarly, 1.0 μM BEZ235 profoundly inhibited tumor cell growth <I>in vitro</I> when compared to control (control versus BEZ235, mean growth = 100.0% vs 7.308%, difference = 92.69%, 95% CI = 78.87% to 106.5%, <I>P</I> < .0001). Despite the presence of CDK4 amplification in the patient-derived tumor cells, LEE011 did not considerably inhibit cell proliferation when compared with control (control vs LEE011, mean growth = 100.0% vs 80.23%, difference = 19.77%, 95% CI = 1.828% to 37.72%, <I>P</I> = .0377). The immunoblot analysis showed that BEZ235 treatment decreased pAKT, pmTOR and pERK whereas AZD2014 decreased only pmTOR. <I>CONCLUSION:</I> Taken together, upregulation of mTOR/AKT pathway in sarcoma patient derived cells was considerably inhibited by the treatment of AZD2014 and BEZ235 with downregulation of AKT pathway (greater extent for BEZ235). These molecules may be considered as treatment option in STS patient who have failed to pazopanib in the context of clinical trials.</P>

Fyn promotes proliferation, differentiation, survival and function of osteoclast lineage cells

Kim, Hyun‐,Ju,Warren, Julia T.,Kim, Shin‐,Yoon,Chappel, Jean C.,DeSelm, Carl J.,Ross, F. Patrick,Zou, Wei,Teitelbaum, Steven L. Wiley Subscription Services, Inc., A Wiley Company 2010 Journal of cellular biochemistry Vol.111 No.5

<P><B>Abstract</B></P><P>c‐Src and Lyn are the only Src family kinases (SFKs) with established activity in osteoclasts (OCs). c‐Src promotes function via cytoskeletal organization of the mature resorptive cell while Lyn is a negative regulator of osteoclastogenesis. We establish that Fyn, another SFK, also impacts the OC, but in a manner distinctly different than c‐Src and Lyn. Fyn deficiency principally alters cells throughout the osteoclastogenic process, resulting in diminished numbers of resorptive polykaryons. Arrested OC formation in the face of insufficient Fyn reflects reduced proliferation of precursors, in response to M‐CSF and retarded RANK ligand (RANKL)‐induced differentiation, attended by suppressed activation of the osteoclastogenic signaling molecules, c‐Jun, and NF‐κB. The anti‐apoptotic properties of RANKL are also compromised in cells deleted of Fyn, an event mediated by increased Bim expression and failed activation of Akt. The defective osteoclastogenesis of Fyn−/− OCs dampens bone resorption, in vitro. Finally, while Fyn deficiency does not regulate basal osteoclastogenesis, in vivo, it reduces that stimulated by RANKL by ∼2/3. Thus, Fyn is a pro‐resorptive SFK, which exerts its effects by prompting proliferation and differentiation while attenuating apoptosis of OC lineage cells. J. Cell. Biochem. 111: 1107–1113, 2010. © 2010 Wiley‐Liss, Inc.</P>

Left-Wing Veto Players and Agenda Setters

Julia Hyeyong Kim 한국라틴아메리카학회 2014 라틴아메리카연구 Vol.27 No.2

Why do some states implement economic liberalization policies while others fail to do so? In this paper, I show that the number and ideological positions of the veto players and their interactions with each other explain differences in economic reform efforts and outcomes. Using several indicators of the veto players and their partisanship, I conduct empirical tests of the effects of the number of veto players and their ideological policy preferences on budget balances, as an indicator of reform effort, using panel data analysis of developing democracies from 1978 to 2000. Also, I test the veto players partisanship against an indicator of reform effort outcomes for Latin American countries. I find that the left-wing partisans hinder economic reform efforts while the right-wing veto players, which usually include the agenda setter in these samples, promote economic reform efforts.

Why Does the Left Not Act Left?

Julia Hyeyong Kim 동아시아국제정치학회 2014 국제정치연구 Vol.17 No.1

When testing impact of ideology on economic policy, the prominent literature usually regards government as one entity. That is why the current literature usually looks at the percentage of left or right in legislature when looking at ideological tendency of government policies. However, this paper argues that one needs to disintegrate government as at least two entities?executive and majority party or coalition government from legislature?because history has shown that executives often times deviate from their own party position and platform. Some have argued that ideology does not matter in developing countries because ideologically defined parties do not follow their ideologically framed preference when they come to power. For example, President Menem’s drastic economic reform was considered a major deviation from his party, and scholars have identified the occasion as an outlier or as an example of how ideology does not matter in developing democracies. This paper shows that it is not because ideology does not matter but because ideologically preferred policy choice often shits in order to reflect the changing cost and benefit calculations once the party comes to power, and I provide evidence using economic crisis and policy implementation in developing countries from 1978 to 2006.

Harvesting electrical energy from carbon nanotube yarn twist

Kim, Shi Hyeong,Haines, Carter S.,Li, Na,Kim, Keon Jung,Mun, Tae Jin,Choi, Changsoon,Di, Jiangtao,Oh, Young Jun,Oviedo, Juan Pablo,Bykova, Julia,Fang, Shaoli,Jiang, Nan,Liu, Zunfeng,Wang, Run,Kumar, P American Association for the Advancement of Scienc 2017 Science Vol.357 No.6353

<P>Mechanical energy harvesters are needed for diverse applications, including self-powered wireless sensors, structural and human health monitoring systems, and the extraction of energy from ocean waves. We report carbon nanotube yarn harvesters that electrochemically convert tensile or torsional mechanical energy into electrical energy without requiring an external bias voltage. Stretching coiled yarns generated 250 watts per kilogram of peak electrical power when cycled up to 30 hertz, as well as up to 41.2 joules per kilogram of electrical energy per mechanical cycle, when normalized to harvester yarn weight. These energy harvesters were used in the ocean to harvest wave energy, combined with thermally driven artificial muscles to convert temperature fluctuations to electrical energy, sewn into textiles for use as self-powered respiration sensors, and used to power a light-emitting diode and to charge a storage capacitor.</P>

Understanding the Philosophy of Education of Ellen G. White and John Dewey through a Linguistic Lens

김은영(Kim, Eun-Young Julia) 삼육대학교 신학연구소 2021 신학과 학문 Vol.33 No.-

이 연구는 두 명의 미국 저술가인 Ellen G. White(1827-1915)와 John Dewey (1859-1959)가 저술한 교육에 관한 영향력 있는 두 텍스트를 언어적 렌즈를 통해 분석한다. White와 Dewey의 교육에 관한 철학은 분야에 중요한 영향을 미쳤다. 점점 더 많은 학자들이 특정 주제에 대한 완전한 이해를 얻기 위해 종교 및 기타형이상학적 주제 연구에 언어적 접근 방식을 통합하는 것의 이점을 인식하고 있다. 이 연구에서는 언어 데이터 및 말뭉치 분석을 위해 Lancaster University에서 개발한 소프트웨어 패키지인 LancsBox를 사용하여 White의 저서 Education과 Dewey의 Democracy and Education 을 분석한다. 코퍼스 언어학자들이 사용하는 분석 도구를 사용하여 연어, 의미 네트워크 및 키워드를 통해 교육 아이디어를 이해하는 방법을 보여준다. This study analyzes two influential texts on education written by two American authors, Ellen G. White (1827-1915) and John Dewey (1859-1959) through a linguistic lens. White and Dewey were both influential figures, whose ideas on education made a significant impact in the field of education in their respective communities. Increasingly more scholars are recognizing the benefits of incorporating a linguistic approach to the study of religion and other metaphysical subjects to gain a fuller understanding of a given topic. The current study employs LancsBox, a software package developed at Lancaster University for the analysis of language data and corpora to analyze White’s Education and Dewey’s Democracy and Education. It demonstrates how their ideas of education can be understood through keywords, collocations, semantic networks, and lexical bundles by using an analytical tool employed by corpus linguists.

Adsorption Capacity of Biochar Produced from Coffee Ground on Propionic Acid

Joo Hee Julia LEE,Ho Nam KIM,Jae Young KIM 대한환경공학회 2019 대한환경공학회 학술발표논문집 Vol.2019 No.-

Thermal stability of mullite <i>R</i>Mn₂O₅ (<i>R</i>  =  Bi, Y, Pr, Sm or Gd): combined density functional theory and experimental study

Li, Chenzhe,Thampy, Sampreetha,Zheng, Yongping,Kweun, Joshua M,Ren, Yixin,Chan, Julia Y,Kim, Hanchul,Cho, Maenghyo,Kim, Yoon Young,Hsu, Julia W P,Cho, Kyeongjae IOP 2016 Journal of Physics, Condensed Matter Vol.28 No.12

<P>Understanding and effectively predicting the thermal stability of ternary transition metal oxides with heavy elements using first principle simulations are vital for understanding performance of advanced materials. In this work, we have investigated the thermal stability of mullite <I>R</I>Mn<SUB>2</SUB>O<SUB>5</SUB> (<I>R</I>  =  Bi, Pr, Sm, or Gd) structures by constructing temperature phase diagrams using an efficient mixed generalized gradient approximation (GGA) and the GGA  +  <I>U</I> method. Simulation predicted stability regions without corrections on heavy elements show a 4–200 K underestimation compared to our experimental results. We have found the number of <I>d</I>/<I>f</I> electrons in the heavy elements shows a linear relationship with the prediction deviation. Further correction on the strongly correlated electrons in heavy elements could significantly reduce the prediction deviations. Our corrected simulation results demonstrate that further correction of <I>R</I>-site elements in <I>R</I>Mn<SUB>2</SUB>O<SUB>5</SUB> could effectively reduce the underestimation of the density functional theory-predicted decomposition temperature to within 30 K. Therefore, it could produce an accurate thermal stability prediction for complex ternary transition metal oxide compounds with heavy elements.</P>

Synaptic adhesion molecule IgSF11 regulates synaptic transmission and plasticity

Jang, Seil,Oh, Daeyoung,Lee, Yeunkum,Hosy, Eric,Shin, Hyewon,van Riesen, Christoph,Whitcomb, Daniel,Warburton, Julia M,Jo, Jihoon,Kim, Doyoun,Kim, Sun Gyun,Um, Seung Min,Kwon, Seok-kyu,Kim, Myoung-Hwa NATURE AMERICA 2016 NATURE NEUROSCIENCE Vol.19 No.1

<P>Synaptic adhesion molecules regulate synapse development and plasticity through mechanisms that include trans-synaptic adhesion and recruitment of diverse synaptic proteins. We found that the immunoglobulin superfamily member 11 (IgSF11), a homophilic adhesion molecule that preferentially expressed in the brain, is a dual-binding partner of the postsynaptic scaffolding protein PSD-95 and AMPA glutamate receptors (AMPARs). IgSF11 required PSD-95 binding for its excitatory synaptic localization. In addition, IgSF11 stabilized synaptic AMPARs, as determined by IgSF11 knockdown-induced suppression of AMPAR-mediated synaptic transmission and increased surface mobility of AMPARs, measured by high-throughput, single-molecule tracking. IgSF11 deletion in mice led to the suppression of AMPAR-mediated synaptic transmission in the dentate gyrus and long-term potentiation in the CA1 region of the hippocampus. IgSF11 did not regulate the functional characteristics of AMPARs, including desensitization, deactivation or recovery. These results suggest that IgSF11 regulates excitatory synaptic transmission and plasticity through its tripartite interactions with PSD-95 and AMPARs.</P>