Molecular Simulation Study on Biomimetic Polymeric Adhesives

Joonkyung Jang(장준경) 한국고분자학회 2023 한국고분자학회 학술대회 연구논문 초록집 Vol.48 No.1

Causative Drugs of Drug-Induced Cough: Analysis of Real-world Data from the Korea Adverse Events Reporting System (KAERS)

( Joonkyung Kim ),( Jee Yea Choi ),( Min Ju Jo ),( Sung Jun Chung ),( Yoomi Yeo ),( Hyun Lee ),( Tai Sun Park ),( Dong Won Park ),( Ji-yong Moon ),( Sang-heon Kim ),( Tae-hyung Kim ),( Jang Won Sohn ) 대한결핵 및 호흡기학회 2020 대한결핵 및 호흡기학회 추계학술대회 초록집 Vol.128 No.-

Background Cough is frequently caused by drugs. However, little is known about the epidemiology and causative drugs leading to cough. We analyzed causative drugs and clinical features of drug-induced cough based on 10-year real-world data. Methods We used the database of the Korea Adverse Events Reporting System (KAERS) from January 2009 to December 2018. Cases of drug-induced cough were identified by selecting cases with a cough code of WHO-Adverse Response Terminology without any other adverse events. Causative drugs were compared between acute (<3 weeks) and delayed onset (≥3 weeks). Results In the study period of 10 years, there were 3,021 cases of drug-induced cough. Cough was most frequently caused by cardiovascular drugs (43.8%), followed by respiratory system drugs (14.9 %), including angiotensin-converting enzyme (ACE) inhibitors, antineoplastic and immune-modulating drugs (14.4 %), and anti-infective drug (8.3 %). In acute onset cough, perindopril, docetaxel, ramipril, paclitaxel, and acetylcysteine were found to be frequent causes, while delayed onset cough was commonly caused by perindopril, ramipril, indacaterol, captopril, and imidapril. Conclusion In this analysis of real-world data from a nationwide spontaneous reporting system, various drugs were found to cause cough, while cardiovascular drugs including ACE inhibitors were the most common cause. [This study was funded by the Korea Ministry of Environment (MOE) as ‘‘the Environmental Health Action Program (2016001360003)" and a research grant from the Korea Institute of Drug Safety & Risk Management].

[동력전달계부문] 유압식 가변 밸브 트레인 시스템의 동적거동 해석

이준경(Joonkyung Lee),장시열(Siyoul Jang) 한국자동차공학회 2000 한국자동차공학회 춘 추계 학술대회 논문집 Vol.- No.-

Variable valve timing system with hydraulic damper is studied for the variation of valve lifts, which is closely related to fuel consumption. In this mechanism, the flow through the orifice into the main camber changes in a cycle as the push of earn plunger that is the same as the earn displacement. In consequence, the flow into the main chamber actuates the valve lift. However, the pushing speed of earn plunger that is directly related to engine speed controls the flow rates into the main chamber. With the proposed hydraulic damper system, we can get both valve lift and valve opening time smaller at low speed than at high speed. In our proposed mechanism, the valve lifts are also adjusted by the flow rates into the accumulator which is adjusted by the bleed valve as well as the flow rates into the damper. In the present work, several parameters are analyzed for the validation of hydraulic damper system in the variable valve train system in advance of experimental studies.

Strain effect on ferroelectric polarization of epitaxial LuFeO3 thin films

Ahn, Yoonho,Jang, Joonkyung,Son, Jong Yeog Springer-Verlag 2016 APPLIED PHYSICS A MATERIALS SCIENCE AND PROCESSING Vol.122 No.5

Dewetting transition of water confined between atomically rough surfaces: A lattice gas Monte Carlo simulation study

Bai, Liyi,Jang, Jihye,Zhang, Zhengqing,Jang, Joonkyung Elsevier 2018 Chemical physics letters Vol.694 No.-

<P><B>Abstract</B></P> <P>Using lattice gas Monte Carlo simulations, we studied the dewetting transition of water confined between a spherical tip and a plate, which is relevant to atomic force microscopy measurements conducted in water. The dewetting transition was investigated by varying the tip-plate distance, tip size, and the pressure of water. With introduction of an atomic scale roughness (1 < nm) in the tip and the plate, the dewetting transition significantly increased in range and yielded an enhanced hydrophobic force between the tip and the plate. This finding is in agreement with the experimental results previously reported by Singh et al.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Water confined between a spherical tip and a plate was theoretically studied. </LI> <LI> Lattice gas Monte Carlo simulation on the dewetting transition of confined water. </LI> <LI> Atomic scale roughness significantly affects the dewetting transition. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Thermal Effect on Positive Patterned Self‐Assembled Monolayer Grown from a Droplet of Alkanethiol

Sannyal, Arindam,Jang, Joonkyung,Shajahan, Md.,Saha, Joyanta K. John WileySons, Inc. 2019 Journal of computational chemistry Vol.40 No.30

<P>Atomic force microscope technique is widely used for the spatial narrow deposition of molecules inside the bare space of preexisting self‐assembled monolayer (SAM) matrix. Using molecular dynamics simulation, we studied the formation of positively patterned SAM from a globule of 1‐octadecanethiol (ODT) on predesigned SAM matrix of 1‐dodecanethiol (DDT) and effect of temperature on it. The alkyl chains of ODT SAM were densely packed and ordered by means of chemisorption through sulfur atoms. The circular SAM of ODT contained defects due to the molecules those were standing upside down or trapped inside ODT SAM. We found that with the increase of temperature, these defects moved out by flipping of inverted ODT molecules or building spaces to be adsorbed on Au surface. The ODT molecules on the top of the pile of stable circular SAM or those are upside down and trapped disperse in a unique fashion namely serial pushing through which molecules firstly make a free space to enter inside the adsorbed thiol molecules and then push neighboring molecules to get enough space to be adsorbed on the gold surface. The stability of ODT SAM was confirmed by analyzing different structural properties such as tilt angle, tilt orientation. and backbone orientation. We also calculated the diffusion coefficient of the ODT molecules which were on the top of SAM island. © 2019 Wiley Periodicals, Inc.</P>

Random Walk Simulation for the Growth of Monolayer in Dip Pen Nanolithography

Kim, Hyojeong,Ha, Soojung,Jang, Joonkyung Korean Chemical Society 2013 Bulletin of the Korean Chemical Society Vol.34 No.1

Using a simple random walk model, this study simulated the growth of a self-assembled monolayer (SAM) pattern generated by dip-pen nanolithography (DPN). In this model, the SAM pattern grew mainly via the serial pushing of molecules deposited from the tip. This study examined various SAM patterns, such as lines, crosses and letters, by changing the tip scan speed.

Metastatic Endometrial Cancer Manifesting as a Large Posterior Mediastinal Tumor Compressing Large Airways

( Jee Yea Choi ),( Joonkyung Kim ),( Min Ju Jo ),( Sung Jun Chung ),( Yoomi Yeo ),( Tai Sun Park ),( Dong Won Park ),( Ji-yong Moon ),( Sang-heon Kim ),( Tae Hyung Kim ),( Jang Won Sohn ),( Ho Joo Yoo 대한결핵 및 호흡기학회 2020 대한결핵 및 호흡기학회 추계학술대회 초록집 Vol.128 No.-

Most posterior mediastinal malignancies in adults are of neurogenic origin. Accordingly, metastatic posterior mediastinal tumors are very rare. We report a case where a metastatic endometrial cancer developed in the posterior mediastinum and compress the lower trachea and both main bronchi. A 71-year-old woman who had received concurrent chemoradiation for stage IV endometrial cancer 13 years ago was admitted for progressive dyspnea. A 10 cm-sized posterior mediastinal tumor compressing the lower trachea and both main bronchi was found on the chest computed tomography. Positron tomography showed no metastasis to organs other than the posterior mediastinum. For pathologic confirmation, we performed bronchoscopy and EBUS-TBNA. After the procedure, the patient developed respiratory failure and received mechanical ventilation. The patient was diagnosed with metastatic endometrial adenocarcinoma based on pathologic findings (positive for p16 and TTF-1). She received concurrent chemoradiotherapy to treat metastatic endometrial cancer compressing the airways while receiving mechanical ventilator treatment. Thereafter, the patient can be successfully weaned from the ventilator. To the best of our knowledge, this is the first case in which previous endometrial cancer recurred as a posterior mediastinal tumor without the involvement of other abdominal organs or lungs. Although it is very rare, clinicians should be aware that metastatic cancer can manifest as a single posterior mediastinal tumor and can cause respiratory failure by compressing large airways.

Theoretical Calculations of Infrared Bands of CH₃⁺ and CH₅⁺

Matin, Mohammad A.,Jang, Joonkyung,Park, Seung Min Korean Chemical Society 2013 Bulletin of the Korean Chemical Society Vol.34 No.7

Existing theoretical calculations predict that infrared spectra of the two most fundamental reactive carbo-ions, methyl cation $CH{_3}^+$ with $D_{3h}$ symmetry and protonated methyl cation $CH{_5}^+$ with $C_s(I)$, $C_s(II)$, and $C_{2v}$ symmetries, appear together in the 7-${\mu}m$ region corresponding to the C-H bending modes. Vibrational band profiles of $CH{_3}^+$ and $CH{_5}^+$ have been compared by ab initio calculation methods that use the basis sets of MP2/aug-cc-pVTZ and CCSD(T)/cc-pVTZ. Our results indicate that the bands of rotation-vibration transitions of $CH{_3}^+$ and $CH{_5}^+$ should overlap not only in the 3-${\mu}m$ region corresponding to the C-H stretching modes but also in the 7-${\mu}m$ region corresponding to the C-H bending modes. Five band intensities of $CH{_5}^+$ among fifteen vibrational transitions between 6 and 8 ${\mu}m$ region are stronger than those of the ${\nu}_2$ and ${\nu}_4$ bands in $CH{_3}^+$. Ultimate near degeneracy of the two bending vibrations ${\nu}_2$ and ${\nu}_4$ of $CH{_3}^+$along with the stronger intensities of $CH{_5}^+$ in the three hydrogen scrambling structures may cause extreme complications in the analysis of the high-resolution carbo-ion spectra in the 7-${\mu}m$ region.

Density functional theory study on ruthenium dyes and dye@TiO₂ assemblies for dye sensitized solar cell applications

Chitumalla, Ramesh Kumar,Jang, Joonkyung Elsevier Science B.V., Amsterdam. 2018 SOLAR ENERGY -PHOENIX ARIZONA THEN NEW YORK- Vol.159 No.-

<P><B>Abstract</B></P> <P>Cyclometalated ruthenium dyes improve significantly the performance of dye sensitized solar cells (DSSCs) based on conventional ruthenium dyes. Here, this study examined four thiocyanate-free cyclometalated ruthenium dyes using the density functional theory (DFT). The geometrical, electronic structural, and photophysical propertiesof the dyes and the dyes tethered to a TiO<SUB>2</SUB> surface were examined in both the presence and absence of an acetonitrile solvent. The Kohn-Sham eigenvalues of the molecular orbitals of the dyes were destabilized by <I>ca</I>. 2 eV in the presence of the solvent. The absorption peaks did not change significantly in position but hyperchromic shifts of more than two-fold occurred. When adsorbed on a TiO<SUB>2</SUB> surface, the dyes showed redshifted absorption of approximately 20 nm. To the best of our knowledge, a systematic and comprehensive first-principles investigation on cyclometalated ruthenium dyes in vacuum, solvent, and tethered to TiO<SUB>2</SUB> has been carried out for the first time.</P> <P><B>Highlights</B></P> <P> <UL> <LI> DFT study on cyclometalated Ru dyes in gas phase, solution, and on TiO<SUB>2</SUB>. </LI> <LI> Investigation of solvent effect on dyes and dye-sensitized TiO<SUB>2</SUB>. </LI> <LI> Destabilization of molecular orbitals of the dyes by 2 eV upon solvation. </LI> <LI> Dyes showed more than twofold hyperchromic shift in absorption in the solvent. </LI> <LI> Upon adsorption on TiO<SUB>2</SUB>, the dyes have shown a redshift of 20 nm in the absorption. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>The dye interaction with solvent causes significant variations in their physical and chemical properties. The solvent in dye sensitized solar cells strongly affects the device efficiency and stability. The present study investigates the effect of acetonitrile solvent on the structural, electrochemical, and optical properties of four cyclometalated ruthenium dyes and dye@TiO<SUB>2</SUB> assemblies employing DFT/TDDFT and periodic-DFT methods. This study also investigates how anchoring of the dye on TiO<SUB>2</SUB> surface affects their electrochemical and photophysical behavior.</P> <P>[DISPLAY OMISSION]</P>