Polymer Thin Film–Induced Tumor Spheroids Acquire Cancer Stem Cell–like Properties

Choi, Minsuk,Yu, Seung J.,Choi, Yoonjung,Lee, Hak R.,Lee, Eunbeol,Lee, Eunjung,Lee, Yumi,Song, Junhyuk,Son, Jin G.,Lee, Tae G.,Kim, Jin Y.,Kang, Sukmo,Baek, Jieung,Lee, Daeyoup,Im, Sung G.,Jon, Sangyo American Association for Cancer Research 2018 Cancer Research Vol.78 No.24

<P>A new cell culture technology enables highly tumorigenic 3D spheroids to be easily generated from various cancer cell sources in the common laboratory.</P><P><B></B></P><P>Although cancer stem cells (CSC) are thought to be responsible for tumor recurrence and resistance to chemotherapy, CSC-related research and drug development have been hampered by the limited supply of diverse, patient-derived CSC. Here, we present a functional polymer thin film (PTF) platform that promotes conversion of cancer cells to highly tumorigenic three-dimensional (3D) spheroids without the use of biochemical or genetic manipulations. Culturing various human cancer cells on the specific PTF, poly(2,4,6,8-tetravinyl-2,4,6,8-tetramethyl cyclotetrasiloxane) (pV4D4), gave rise to numerous multicellular tumor spheroids within 24 hours with high efficiency and reproducibility. Cancer cells in the resulting spheroids showed a significant increase in the expression of CSC-associated genes and acquired increased drug resistance compared with two-dimensional monolayer-cultured controls. These spheroids also exhibited enhanced xenograft tumor-forming ability and metastatic capacity in nude mice. By enabling the generation of tumorigenic spheroids from diverse cancer cells, the surface platform described here harbors the potential to contribute to CSC-related basic research and drug development.</P><P><B>Significance:</B></P><P>A new cell culture technology enables highly tumorigenic 3D spheroids to be easily generated from various cancer cell sources in the common laboratory.</P>

Comparison of the pharmacokinetics and tolerability of HCP1004 (a fixed-dose combination of naproxen and esomeprazole strontium) and VIMOVO ^® (a marketed fixed-dose combination of naproxen and esomeprazole magnesium) in healthy volunteers

Choi, YoonJung,Han, HyeKyung,Shin, Dongseong,Lim, Kyoung Soo,Yu, Kyung-Sang Dove Medical Press 2015 Drug design, development and therapy Vol.9 No.-

<P><B>Background</B></P><P>HCP1004 is a newly developed fixed-dose combination of naproxen (500 mg) and esomeprazole strontium (20 mg) that is used in the treatment of rheumatic diseases and can reduce the risk of nonsteroidal anti-inflammatory drug-associated ulcers. The aim of this study was to evaluate the pharmacokinetics (PK) and safety of HCP1004 compared to VIMOVO<SUP>®</SUP> (a marketed fixed-dose combination of naproxen and esomeprazole magnesium).</P><P><B>Subjects and methods</B></P><P>An open-label, randomized, two-treatment, two-sequence crossover, single-dose clinical study was conducted in 70 healthy volunteers. In each period, a reference (VIMOVO<SUP>®</SUP>) or test (HCP1004) drug was administered orally, and serial blood samples for PK analysis were collected up to 72 hours after dosing. To evaluate the PK profiles, the maximum plasma concentration (C<SUB>max</SUB>) and the area under the concentration–time curve from 0 to the last measurable time (AUC<SUB>0−t</SUB>) were estimated using a noncompartmental method. Safety profiles were evaluated throughout the study.</P><P><B>Results</B></P><P>Sixty-six of the 70 subjects completed the study. The C<SUB>max</SUB> (mean ± standard deviation) and AUC<SUB>0−t</SUB> (mean ± standard deviation) for naproxen in HCP1004 were 61.67±15.16 µg/mL and 1,206.52±166.46 h·µg/mL, respectively; in VIMOVO<SUP>®</SUP>; these values were 61.85±14.54 µg/mL and 1,211.44±170.01 h·µg/mL, respectively. The C<SUB>max</SUB> and AUC<SUB>0−t</SUB> for esomeprazole in HCP1004 were 658.21±510.91 ng/mL and 1,109.11±1,111.59 h·ng/mL, respectively; for VIMOVO<SUP>®</SUP>, these values were 595.09±364.23 ng/mL and 1,015.12±952.98 h·ng/mL, respectively. The geometric mean ratios and 90% confidence intervals (CIs) (HCP1004 to VIMOVO<SUP>®</SUP>) of the C<SUB>max</SUB> and AUC<SUB>0−t</SUB> of naproxen were 0.99 (0.94–1.06) and 1.00 (0.98–1.01), respectively. For esomeprazole, the geometric mean ratios (90% CI) for the C<SUB>max</SUB> and AUC<SUB>0−t</SUB> were 0.99 (0.82–1.18) and 1.04 (0.91–1.18), respectively. The overall results of the safety assessment showed no clinically significant issues for either treatment.</P><P><B>Conclusion</B></P><P>The PK of HCP1004 500/20 mg was comparable to that of VIMOVO<SUP>®</SUP> 500/20 mg for both naproxen and esomeprazole after a single oral dose. Both drugs were well-tolerated without any safety issues.</P>

Valley of Chaos

Yoonjung Choi(최윤정) 한국디자인학회 2023 한국디자인학회 국제초대전도록 Vol.2023 No.6

Comparisons of the pharmacokinetics and tolerability of fixed-dose combinations of amlodipine besylate/losartan and amlodipine camsylate/losartan in healthy subjects: a randomized, open-label, single-dose, two-period, two-sequence crossover study

Choi, YoonJung,Lee, SeungHwan,Cho, Sang-Min,Kang, Won-Ho,Nam, Kyu-Yeol,Jang, In-Jin,Yu, Kyung-Sang Dove Medical Press 2016 Drug design, development and therapy Vol.10 No.-

<P><B>Background</B></P><P>A fixed-dose combination (FDC) of amlodipine and losartan has been used to reduce blood pressure in patients whose hypertension is not sufficiently controlled with either drug alone. The aim of this study was to evaluate the pharmacokinetic (PK) characteristics and tolerability of an FDC of 6.94 mg amlodipine besylate (5 mg as amlodipine)/50 mg losartan potassium compared to an FDC of 5 mg amlodipine camsylate/50 mg losartan potassium in healthy subjects.</P><P><B>Subjects and methods</B></P><P>A randomized, open-label, single-dose, two-period, two-sequence crossover study was conducted on 46 healthy male subjects. Blood concentrations were measured by liquid chromatography–tandem mass spectrometry. Blood samples were collected up to 144 hours post dose for each period. PK parameters were calculated in each treatment group using a noncompartmental method. The 90% confidence intervals (CIs) of the geometric mean ratios of the two treatments for the maximum plasma concentration (<I>C</I><SUB>max</SUB>) and the area under the concentration curve from time zero to the last quantifiable time point (AUC<SUB>0–t</SUB>) were estimated. Tolerability assessments were performed for all subjects who received the drug at least once.</P><P><B>Results</B></P><P>The PK profiles of the two treatments were similar. For amlodipine, the geometric mean ratios (90% CIs) of amlodipine besylate to amlodipine camsylate for the <I>C</I><SUB>max</SUB> and AUC<SUB>0–t</SUB> were 0.98 (0.94−1.01) and 0.97 (0.93−1.01), respectively. The corresponding values for losartan were 0.91 (0.81−1.02) and 1.05 (0.98−1.12), respectively. The incidence of adverse events was not significantly different between the two treatments, and both were well tolerated.</P><P><B>Conclusion</B></P><P>An FDC of 6.94 mg amlodipine besylate (5 mg as amlodipine)/50 mg losartan potassium produced similar results to an FDC of 5 mg amlodipine camsylate/50 mg losartan potassium treatment with respect to the PK parameters of amlodipine and losartan based on <I>C</I><SUB>max</SUB> and AUC<SUB>0–t</SUB> values. The amlodipine besylate/losartan potassium combination was well tolerated by healthy male subjects.</P>

Teaching Global Citizenship in Social Studies : A Case Study of an Exemplary U.S. High School Teacher

Yoonjung Choi 이화여자대학교 사범대학 교과교육연구소 2015 교과교육학연구 Vol.19 No.3

본 연구는 미국 고등학교 사회과 교사의 세계시민교육 모범사례를 소개하고 한국 사회과 수업에서 활용 가능한 세계시민교육 교육과정 및 교수학습방법론에 대한 실천적 시사점을 제언하고자 한다. 정의와 협력, 그리고 민주적 가치를 지향하는 세계시민 교육모델에 근거한 본 연구는, 질적연구방법을 통해 한 학기 동안 교사 Julia의 수업을 관찰하고 교사와의 심층 면접을 통해 학교 현장에서 실천 가능한 세계시민교육의 모델을 탐구하였다. 분석 결과는 Julia는 다음과 같은 다섯 가지의 접근법을 통해 세계시민교육을 실천하고 있었다: (1) 해석과 분석으로서의 세계사와 문화와(Global History and Culture as Interpretationand Analysis), (2) 지역에서 세계로(FromLocal to Global), (3) 다문화에 대한 이해와 관용, 그리고 존중(Diversity, tolerance, and respect), (4) 시사문제에 대한 지속적 관심(Stay Tuned for Current Events), (5) 시각자료의 텍스트적 활용(Visual Texts). 이와 같은 교육과정 및 교수학습방법론적 접근법은 세계시민교육을 표면적인, 따라서 달성하기 어려운, 사회과 교육의 목표로 치부하는 것이 아닌, 일선 교육 현장에서 학습활동을 통해 성취 가능한 실질적인 교육 내용으로 다루고 있음을 확인할 수 있었다. 특히 Julia의 수업 사례는 기존의 학교교육과정 및 한국 사교육 시장의 지배적인 담론을 형성해온 신자유주의와 국가주의적 세계시민성을 넘어서 보다 협력적인 공동체로서의 세계 및 세계시민성을 강조한다는 차원에서 주요한 함의를 찾을 수 있다. 나아가 본 연구는 Julia의 수업과 같은 모범사례 연구를 실증적 사례로 다룸으로써 그동안 이론적 담론과 교육과정에 대한 제언 위주였던 국내 세계시민교육 연구의 저변을 확대하고 세계시민교육을 위한 다양한 실천적 논의에 함의를 제공하고자 한다. This study explored how global citizenship as an overarching aim of social studies can be realized and meaningfully delivered to students in a high school social studies classroom. Using a case study of an exemplary social studies teacher, Julia, this study focused on her curricular meaning making and pedagogical decision making as ways to promote global citizenship in a 9th grade social studies classroom in the United States. The findings of this study demonstrate that Julia's curricular decisions and pedagogical practices largely advocated world justice and governance and cosmopolitan notions of global citizenship, and emphasized a cooperative nature and dialogic understanding of the world. Specific pedagogical approaches Julia used are as follows: (1) global history and culture as interpretation and analysis, (2) from local to global, (3) cultural diversity, tolerance, and respect, (4) stay tuned for current events, and (5) visual texts. in-class activity, primary sources, student work sample, and homework/assignment guidelines are presented as examples of her actual teaching practices. This study, based upon a real-world classroom observation and interview data, seeks to provide implications for global citizenship education in Korea that goes beyond the narrowly defined nationalist and overly competitive neoliberal discourses and pursues more cooperative and justice-oriented visions of the world, and to contribute to the generation of more classroom-based empirical studies that would move the field forward.

Galvanically ReplacedHollow Au–Ag Nanospheres:Study of Their Surface Plasmon Resonance

Choi, Yoonjung,Hong, Soonchang,Liu, Lichun,Kim, Seong Kyu,Park, Sungho American ChemicalSociety 2012 Langmuir Vol.28 No.16

<P>We synthesized hollow Au-Ag nanospheres (NSs) by employing a galvanic replacement reaction between HAuCl4 and Ag NSs. Uniform Ag NSs with controllable sizes were synthesized as sacrificial templates by a seed-mediated strategy. The atomic ratio of Au to Ag in Au-Ag NSs was tunable by controlling the reagent concentration. UV-vis extinction spectra acquired from well-dispersed colloidal NS solutions were used to investigate the optical properties of the solutions. In addition to a common dipole mode exhibited on most transition metal nanoparticles, we observed a quadrupole plasmon resonance mode when the diameters of the Ag and Au-Ag NSs were larger than 100 nm. The quadrupole and dipole peaks both shifted to longer wavelengths with increased Au content in Au-Ag NSs. The experimental observation of optical properties of hollow Au-Ag NSs was compared with the theoretical simulation using DDA calculation, showing a good agreement.</P>

Optical Sensitivity Comparison of Multiblock Gold–Silver Nanorods Toward Biomolecule Detection: Quadrupole Surface Plasmonic Detection of Dopamine

Choi, Yoonjung,Choi, Jin-Ha,Liu, Lichun,Oh, Byung-Keun,Park, Sungho American Chemical Society 2013 Chemistry of materials Vol.25 No.6

<P>In this work, we tested multiblock nanorods (NRs) with Au and Ag segments for the surface plasmonic detection of dopamine (DA). A change in the quadrupole surface plasmon mode was found to be sensitive to the Au/Ag block length and relative block ratio in a single NR. The surfaces of the NRs were decorated with monoclonal antibody (Mab) against DA. By comparing the results for pure Au NRs with those obtained for multiblock Au–Ag–Au NRs, we found that the magnitude of peak-shifting for the multiblock NRs was much larger than that for pure Au NRs. This result was attributed to the higher sensitivity of Ag to a change in the dielectric constant of the surrounding medium when compared to Au and the sensitive surface plasmon coupling at the junction between Au and Ag blocks. The magnitude of peak-shifting was tuned as a function of both the length of the Ag block and the number of repeating units of Au and Ag in the NRs.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/cmatex/2013/cmatex.2013.25.issue-6/cm304030r/production/images/medium/cm-2012-04030r_0009.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/cm304030r'>ACS Electronic Supporting Info</A></P>

소프트웨어 사용성 개선을 위한 사용성 심사 및 프로세스 지원 시스템 평가

최윤정(Yoonjung Choi),이은석(Eunseok Lee) 한국정보과학회 2003 한국정보과학회 학술발표논문집 Vol.2003 No.2

이클립스 기반 프로젝트 실행 및 자산 관리를 위한 개발방법론 지원 시스템 설계

최윤정 ( Yoonjung Choi ),하수정 ( Su-jung Ha ),김진삼 ( Jin-sam Kim ) 한국정보처리학회 2005 한국정보처리학회 학술대회논문집 Vol.12 No.2

소프트웨어 개발 조직은 구성원들로 하여금 자발적이고 지속적인 개발방법론 활용 및 개선을 유도하기 위하여 효율적인 개발방법론 정의, 조정, 참조에 대한 지원뿐 만 아니라 보다 적극적인 개발방법론의 프로젝트 적용, 프로젝트 수행 경험(수행사례)의 지식화로 전사적인 지식 자산을 공유할 수 있는 환경을 지원해야 한다. 본 논문에서는 이러한 프로젝트 경험의 지식화를 위해 종료된 프로젝트에 적용되었던 방법론 내역과 프로젝트 산출물에 대한 재사용을 위한 자산화가 가능하도록 지원하는 Eclipse 기반의 플러그인을 설계하고자 한다.

사회과 예비교사들의 교육봉사활동 경험과 교사전문성 신장

최윤정(Yoonjung Choi) 한국사회과교육연구학회 2015 사회과교육 Vol.54 No.1

본 연구는 사회과 예비교사들의 교육봉사활동 경험과 이를 통한 교사전문성 신장에 대해 살펴보았다. 경험이론을 바탕으로 한 본 연구는 한국 한 사범대학 (일반)사회교육전공에서 실시하는 ‘교육봉사의 이론과 실제’라는 과목을 사례로 선정하여 첫째, 사회과 예비교사들이 교육봉사활동을 어떻게 경험하고 있는지 현황을 파악하고, 둘째, 이러한 경험이 예비교사들의 교사전문성 신장에 미치는 영향은 무엇인지, 셋째, 제한점과 보완점은 무엇인지 탐색해보았다. 연구자는 혼합연구방법을 사용하여 2009년부터 2014년까지 최근 6년간 교육봉사활동을 경험한 사회과 예비교사 65명이 작성한 실습일지 및 자기성찰지를 대상으로 내용 분석을 실시하였다. 연구결과는 사회과에서의 교육봉사의 의미를 민주시민성 이론과 함께 논의해보고 실증적 자료를 분석한 결과를 통해 교사교육에 대한 함의를 제공할 수 있을 것이다. This study explores preservice social studies teachers’ experiences of educational service learning and development of teacher professionalism. Framed by theory of experience, this study chose one teacher education program and its educational service learning program, Theory and Practice of Educational Services, and examined the following research questions: (a) what preservice social studiees teachers’ experiences of participating in educational service learning programs were, (b) if and how they were able to learn, develop, and reflect on teacher professionalism throughout the experiences, and (c) what drawbacks were noticed in such service learning programs. This mixed-method study analyzed reflective essays and program participation records that were written by 65 preservice social studies teachers who had participated in the program over the course of the past three years (2012-2014). This study seeks to contribute to generating further discussion on what it means to educate caring and capable social studies teachers who are equipped with participation-oriented democratic citizenship, and providing practical implications for service learning education for preservice teachers.