D–A copolymer with high ambipolar mobilities based on dithienothiophene and diketopyrrolopyrrole for polymer solar cells and organic field-effect transistors

Kim, In-Bok,Khim, Dongyoon,Jang, Soo-Young,Kim, Jihong,Yu, Byung-kwan,Kim, Yeong-A,Kim, Dong-Yu Elsevier 2015 ORGANIC ELECTRONICS Vol.26 No.-

<P><B>Abstract</B></P> <P>Donor–acceptor (D–A) type conjugated polymers have been developed to absorb longer wavelength light in polymer solar cells (PSCs) and to achieve a high charge carrier mobility in organic field-effect transistors (OFETs). PDTDP, containing dithienothiophene (DTT) as the electron donor and diketopyrrolopyrrole (DPP) as the electron acceptor, was synthesized by stille polycondensation in order to achieve the advantages of D–A type conjugated polymers. The polymer showed optical band gaps of 1.44 and 1.42eV in solution and in film, respectively, and a HOMO level of 5.09eV. PDTDP and PC<SUB>71</SUB>BM blends with 1,8-diiodooctane (DIO) exhibited improved performance in PSCs with a power conversion efficiency (PCE) of 4.45% under AM 1.5G irradiation. By investigating transmission electron microscopy (TEM), atomic force microscopy (AFM), and the light intensity dependence of <I>J</I> <SUB>SC</SUB> and <I>V</I> <SUB>OC</SUB>, we conclude that DIO acts as a processing additive that helps to form a nanoscale phase separation between donor and acceptor, resulting in an enhancement of <I>μ</I> <SUB>h</SUB> and <I>μ</I> <SUB>e</SUB>, which affects the <I>J</I> <SUB>SC</SUB>, EQE, and PCE of PSCs. The charge carrier mobilities of PDTDP in OFETs were also investigated at various annealing temperatures and the polymer exhibited the highest hole and electron mobilities of 2.53cm<SUP>2</SUP> V<SUP>−1</SUP> s<SUP>−1</SUP> at 250°C and 0.36cm<SUP>2</SUP> V<SUP>−1</SUP> s<SUP>−1</SUP> at 310°C, respectively. XRD and AFM results demonstrated that the thermal annealing temperature had a critical effect on the changes in the crystallinity and morphology of the polymer. The low-voltage device was fabricated using high-<I>k</I> dielectric, P(VDF-TrFE) and P(VDF-TrFE-CTFE), and the carrier mobility of PDTDP was reached 0.1cm<SUP>2</SUP> V<SUP>−1</SUP> s<SUP>−1</SUP> at <I>V</I> <SUB>d</SUB> =−5V. PDTDP complementary inverters were fabricated, and the high ambipolar characteristics of the polymer resulted in an output voltage gain of more than 25.</P> <P><B>Highlights</B></P> <P> <UL> <LI> We describe the synthesis and characterizations for donor–acceptor copolymer, PDTDP. </LI> <LI> PDTDP shows high crystallinity and appropriate energy levels for ambipolar OFETs. </LI> <LI> We achieved a 4.45% efficiency with processing additive, DIO, in PSCs. </LI> <LI> We achieve ambipolar field effect mobilities, <I>μ</I> <SUB>h</SUB> ∼2.53 and <I>μ</I> <SUB>e</SUB> ∼0.36cm<SUP>2</SUP> V<SUP>−1</SUP> s<SUP>−1</SUP>. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

MERS 사태에 대한 대응 네트워크 분석

김지홍(Jihong Kim),송준호(Junho Song),김유심(Yushim Kim),구민영(Minyoung Ku),오성수(Seong Soo Oh),박희진(Heejin Park),차재혁(Jaehyuk Cha),김상욱(Sang-wook Kim) 한국정보과학회 2018 한국정보과학회 학술발표논문집 Vol.2018 No.12

Screening for<i>Escherichia coli</i>K-12 genes conferring glyoxal resistance or sensitivity by transposon insertions

Lee, Changhan,Kim, Jihong,Kwon, Minsuk,Lee, Kihyun,Min, Haeyoung,Kim, Seong Hun,Kim, Dongkyu,Lee, Nayoung,Kim, Jiyeun,Kim, Doyun,Ko, Changmin,Park, Chankyu,Calendar, Richard Published by Elsevier/North Holland on behalf of t 2016 FEMS microbiology letters Vol.363 No.18

Zinc-mediated Reversible Multimerization of Hsp31 Enhances the Activity of Holding Chaperone

Kim, Jihong,Choi, Dongwook,Cha, So-Young,Oh, Young-Mee,Hwang, Eunha,Park, Chankyu,Ryu, Kyoung-Seok Elsevier 2018 Journal of molecular biology Vol.430 No.12

<P><B>Abstract</B></P> <P>Hsp31 protein, belonging to the DJ-1/ThiJ/PfpI superfamily, increases the survival of <I>Escherichia coli</I> under various stresses. While it was reported as a holding chaperone, Hsp31 was also shown to exhibit the glyoxalase III activity in subsequent study. Here, we describe our finding that Hsp31 undergoes a Zn<SUP>+2</SUP>-mediated multimerization (HMW<SUB>Zinc</SUB>), resulting in an enhanced chaperone activity. Furthermore, it was shown that the formation of HMW<SUB>Zinc</SUB> is reversible such that the oligomer dissociates into the native dimer by EDTA incubation. We attempted to determine the structural change involving the transition between the native dimer and HMW<SUB>Zinc</SUB> by adding Ni<SUP>+2</SUP>, which is Zn<SUP>+2</SUP>-mimetic, producing a potential intermediate structure. An analysis of this intermediate revealed a structure with hydrophobic interior exposed, due to an unfolding of the N-terminal loop and the C-terminal β-to-α region. A treatment with hydrogen peroxide accelerated HMW<SUB>Zinc</SUB> formation, so that the Hsp31<SUP>C185E</SUP> mutant rendered the formation of HMW<SUB>Zinc</SUB> even at 45 °C. However, the presence of Zn<SUP>+2</SUP> in the catalytic site antagonizes the oxidation of C185, implying a negative role. Our results suggest an unprecedented mechanism of the enhancing chaperone activity by Hsp31, in which the reversible formation of HMW<SUB>Zinc</SUB> occurs in the presence of heat and Zn<SUP>+2</SUP> ion.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Hsp31 forms Zn<SUP>+2</SUP>-coordinated multimer (HMW<SUB>Zinc</SUB>) in the presence of heat stress and Zn<SUP>+2</SUP>. </LI> <LI> HMW<SUB>Zinc</SUB> acquires an enhanced chaperone activity and is reversible to native dimer. </LI> <LI> The oxidation of C185 located in the catalytic site accelerates the HMW<SUB>Zinc</SUB> formation. </LI> <LI> The binding of Zn<SUP>+2</SUP> to the catalytic site retardates the oxidation of C185. </LI> </UL> </P> <P><B>Graphical Abstract</B></P> <P>[DISPLAY OMISSION]</P>

ARC-H: Adaptive replacement cache management for heterogeneous storage devices

Kim, Young-Jin,Kim, Jihong Elsevier 2012 JOURNAL OF SYSTEMS ARCHITECTURE - Vol.58 No.2

<P><B>Abstract</B></P><P>Heterogeneous storage architectures combine the strengths of different storage devices in a synergistically useful fashion, and are increasingly being used in mobile storage systems. In this paper, we propose ARC-H, an adaptive cache replacement algorithm for heterogeneous storage systems consisting of a hard disk and a NAND flash memory. ARC-H employs a dynamically adaptive management policy based on ghost buffers and takes account of recency, I/O cost per device, and workload patterns in making cache replacement decisions. Realistic trace-driven simulations show that ARC-H reduces service time by up to 88% compared with existing caching algorithms with a 20Mb cache. ARC-H also reduces energy consumption by up to 81%.</P>

Association of Specific Immunoglobulin E to Staphylococcal Enterotoxin with Airway Hyperresponsiveness in Asthma Patients

Kim, Seong Han,Yang, Seo Yeon,You, Jihong,Lee, Sang Bae,You, Jin,Chang, Yoon Soo,Kim, Hyung Jung,Ahn, Chul Min,Byun, Min Kwang,Park, Hye Jung,Park, Jung-Won The Korean Academy of Tuberculosis and Respiratory 2016 Tuberculosis and Respiratory Diseases Vol.79 No.4

Background: Specific immunoglobulin E (IgE) sensitization to staphylococcal enterotoxin (SE) has been recently considered to be related to allergic disease, including asthma. Despite studies on specific IgE (sIgE) to SE and its relationship to asthma diagnosis and severity, the association of sIgE to SE with airway hyperresponsiveness (AHR) remains unclear. Methods: We enrolled 81 asthma patients admitted to the Severance Hospital in Korea from March 1, 2013, to February 28, 2015 and retrospectively reviewed the electronic medical records of the enrolled subjects. The serum levels of sIgE to SE (A/B) of all subjects was measured using the ImmunoCAP 250 (Phadia) system with SE-sIgE positive defined as >0.10 kU/mL. Results: The SE-sIgE level was not significantly correlated with asthma severity (forced expiratory volume in 1 second [$FEV_1$], $FEV_1$/forced vital capacity, sputum eosinophils, and serum eosinophils), whereas the SE-sIgE level in patients with positive AHR ($mean{\pm}standard$ error of the mean, $0.606{\pm}0.273kU/mL$) was significantly higher than that in patients with negative AHR ($0.062{\pm}0.015kU/mL$, p=0.034). In regression analysis, SE sensitization (sIgE to SE ${\geq}0.010kU/mL$) was a significant risk factor for AHR, after adjustment for age, sex, $FEV_1$, and sputum eosinophils (odds ratio, 7.090; 95% confidence interval, 1.180-42.600; p=0.032). Prevalence of SE sensitization was higher in patients with allergic rhinitis and non-atopic asthma patients, as compared to patients without allergic rhinitis and atopic asthma patients, respectively, but without statistical significance. Conclusion: SE sensitization is significantly associated with AHR.

Simultaneous Enhancement of Electron Injection and Air Stability in N-Type Organic Field-Effect Transistors by Water-Soluble Polyfluorene Interlayers

Kim, Jihong,Khim, Dongyoon,Kang, Rira,Lee, Seung-Hoon,Baeg, Kang-Jun,Kang, Minji,Noh, Yong-Young,Kim, Dong-Yu American Chemical Society 2014 ACS APPLIED MATERIALS & INTERFACES Vol.6 No.11

<P>Here, we report the simultaneous attainment of efficient electron injection and enhanced stability under ambient conditions for top-gate/bottom-contact (TG/BC), n-type, organic field-effect transistors (OFETs) using water-soluble polyfluorene derivatives (WPFs). When inserting the WPF interlayers between a semiconductor and the BC Au electrodes, initially the ambipolar (6,6)-phenyl-C<SUB>61</SUB>butyric acid methyl ester (PCBM) OFETs were fully converted to unipolar charge transport characteristics that were exclusively n-type with significantly increased electron mobilities as high as 0.12 cm<SUP>2</SUP>/(V s) and a decreased threshold voltage. These improvements were mostly attributed to the interfacial dipoles of WPF layers that aligned to form a favorable energy band structure for efficient electron injection and to effectively block counter charge carriers. These were confirmed when values for the reduced work function of metal electrodes with WPFs and their correlated contact resistance were measured via the ultraviolet photoemission spectroscopy and the transmission-line method, respectively. Moreover, the WPF interlayers played an important role in air stability of PCBM OFETs that exhibited higher and appreciably enhanced by increasing the ethylene-oxide side chain lengths of WPFs, which presumably was due to the water/oxygen/ion capturing effects in the hydrophilic interlayers.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/aamick/2014/aamick.2014.6.issue-11/am500466q/production/images/medium/am-2014-00466q_0007.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/am500466q'>ACS Electronic Supporting Info</A></P>

Per-deuteration and NMR experiments for the backbone assignment of 62 kDa protein, Hsp31

Kim, Jihong,Choi, Dongwook,Park, Chankyu,Ryu, Kyoung-Seok Korean Magnetic Resonance Society 2015 Journal of the Korean Magnetic Resonance Society Vol.19 No.3

Hsp31 protein is one of the members of DJ-1 superfamily proteins and has a dimeric structure of which molecular weight (MW) is 62 kDa. The mutation of DJ-1 is closely related to early onset of Parkinson's disease. Hsp31 displays $Zn^{+2}$-binding activity and was first reported to be a holding chaperone in E. coli. Its additional glyoxalase III active has recently been characterized. Moreover, an incubation at $60^{\circ}C$ induces Hsp31 protein to form a high MW oligomer (HMW) in vitro, which accomplishes an elevated holding chaperone activity. The NMR technique is elegant method to probe any local or global structural change of a protein in responses to environmental stresses (heat, pH, and metal). Although the presence of the backbone chemical shifts (bbCSs) is a prerequisite for detailed NMR analyses of the structural changes, general HSQC-based triple resonance experiments could not be used for 62 kDa Hsp31 protein. Here, we prepared the per-deuterated Hsp31 and performed the TROSY-based triple resonance experiments for the bbCSs assignment. Here, detailed processes of per-deuteration and the NMR experiments are described for other similar NMR approaches.

Solution-Processed Barium Salts as Charge Injection Layers for High Performance N-Channel Organic Field-Effect Transistors

Kim, Nam-Koo,Khim, Dongyoon,Xu, Yong,Lee, Seung-Hoon,Kang, Minji,Kim, Jihong,Facchetti, Antonio,Noh, Yong-Young,Kim, Dong-Yu American Chemical Society 2014 ACS APPLIED MATERIALS & INTERFACES Vol.6 No.12

<P>N-channel organic field-effect transistors (OFETs) have generally shown lower field-effect mobilities (μ<SUB>FET</SUB>) than their p-type counterparts. One of the reasons is the energetic misalignment between the work function (WF) of commonly used charge injection electrode, i.e. gold (Au), and the lowest unoccupied molecular orbital (LUMO) of n-channel electron-transporting organic semiconductors. Here, we report barium salts as solution-processed interlayers, to improve the electron-injection and/or hole-blocking in top-gate/bottom-contact n-channel OFETs, based on poly{[<I>N,N</I>′-bis(2-octyldodecyl)-naphthalene-1,4,5,8-bis(dicarboximide)-2,6-diyl]-<I>alt</I>-5,5′-(2,2′-dithiophene)} (P(NDI2OD-T2)) and phenyl-C61-butyric acid methyl ester (PC<SUB>61</SUB>BM). Two different barium salts, barium hydroxide (Ba(OH)<SUB>2</SUB>) and barium chloride (Ba(Cl)<SUB>2</SUB>), are employed as the ultrathin interlayer (∼2 nm); and they effectively tune the WF of Au from 4.9 eV, to as low as 3.5 eV. The resulting n-channel OFETs exhibit significantly improved μ<SUB>FET</SUB>, approaching 2.6 cm<SUP>2</SUP>/(V s) and 0.1 cm<SUP>2</SUP>/(V s) for the best P(NDI2OD-T2) and PC<SUB>61</SUB>BM devices, respectively, with Ba(OH)<SUB>2</SUB> as interlayer.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/aamick/2014/aamick.2014.6.issue-12/am502007j/production/images/medium/am-2014-02007j_0008.gif'></P>

Prognosis of HER2 overexpression in small T1N0M0 breast cancer: A single center experience in Korea

( Jihong Bae ),( Hee Kyung Ahn ),( Kwan Il Kim ),( Heung Kyu Park ),( Yong Soon Chun ),( Young Saing Kim ),( Inkeun Park ),( Junshik Hong ),( Sun Jin Sym ),( Jinny Park ),( Eun Kyung Cho ),( Jae Hoon 대한내과학회 2015 대한내과학회 추계학술대회 Vol.2015 No.1

Introduction: A role of adjuvant treatment in patients with T1abN0M0 human epidermal growth factor receptor 2 (HER2)-positive breast cancer remains controversial. In this study, we investigated the prognosis of pT1abN0M0 breast cancer according to HER2 and hormone-receptor status. Methods: We retrospectively reviewed consecutive 536 patients diagnosed with T1a-cN0M0 breast cancer between 2003 and 2012 in a single center. Invasive disease free survival (IDFS), distant recurrence free survival (DRFS), and overall survival (OS) were estimated and compared by Kaplan-Meier method and log-rank test. Results: With a median estimated potential follow-up of 53 months, 5-year IDFS rate was 96.1% (92.3% in T1abN0, 97.3% in T1cN0), DRFS rate 98.3% (97.6% in T1abN0, 98.5% in T1cN0), and OS rate 98.4% (97.6% in T1abN0, 98.6% in T1cN0). Among 142 patients with T1abN0M0, IDFS in HER2 (+) disease (n=31, 5-year IDFS rate 73.2%, 5-year DRFS rate 96.3%) was significantly inferior to those with HR (+)/HER2 (-) disease (n=63, 5-year IDFS rate 98.4%, no distant recurrence has occurred during follow-up period) or TN (n=14, no recurrence has occurred during follow-up period). IDFS in HER2 (+) T1abN0 disease was not significantly different by HR status (5-year IDFS rate 64.1% in HR (+) HER2 (+) vs. 40.0% in HR (-) HER2 (+), p=0.104). Conclusions: In Korean patients with T1abN0M0 breast cancer, HER2 overexpression was associated with worse IDFS.