Negative Regulation of Hypoxic Responses via Induced Reptin Methylation

Jason S. Lee,김윤호,김익수,김보규,최희준,이지민,신희재,김정화,김지영,서상범,이호,Olivier Binda,Or Gozani,Gregg L. Semenza,김민형,김근일,황대희,백성희 Sookmyung Women's University Research Institute of 2010 여성과 건강 Vol.6 No.1

Negative Regulation of Hypoxic Responses via Induced Reptin Methylation

Jason S. Lee,김윤호,김익수,김보규,최희준,이지민,신희재,김정화,김지영,서상범,이호,Olivier Binda,Or Gozani,Gregg L. Semenza,김민형,김근일,황대희,백성희 Sookmyung Women's University Research Institute of 2010 여성과 건강 Vol.6 No.1

Directional dependent piezoelectric effect in CVD grown monolayer MoS₂ for flexible piezoelectric nanogenerators

Kim, Sung Kyun,Bhatia, Ravi,Kim, Tae-Ho,Seol, Daehee,Kim, Jung Ho,Kim, Hyun,Seung, Wanchul,Kim, Yunseok,Lee, Young Hee,Kim, Sang-Woo Elsevier 2016 Nano energy Vol.22 No.-

<P><B>Abstract</B></P> <P>Due to the interesting semiconducting and optical properties of transition metal dichalcogenides, they have received particular attention for novel electronics and optoelectronics. In addition it is expected that piezoelectric properties of two-dimensional (2D) layered materials are very useful to realize next generation mechanically powered transparent flexible charge-generating devices. Here we report directional dependent piezoelectric effects in chemical vapor deposition grown monolayer MoS<SUB>2</SUB> for flexible piezoelectric nanogenerators (NGs). It was found that the output power obtained from the NG with the armchair direction of MoS<SUB>2</SUB> is about two times higher than that from the NG with the zigzag direction of MoS<SUB>2</SUB> under the same strain of 0.48% and the strain velocity of 70mm/s. This study provides a new way to effectively harvest mechanical energy using novel flexible piezoelectric NGs based on 2D semiconducting piezoelectric MoS<SUB>2</SUB> for powering low power-consuming electronics and realizing self-powered sensors.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Directional dependent piezoelectric effects in chemical vapor deposition (CVD) grown monolayer MoS<SUB>2</SUB> for flexible piezoelectric nanogenerators (NGs). </LI> <LI> Lateral piezoresponse force microscopy measurements revealed that the magnitude of the piezoelectric polarization in monolayer MoS<SUB>2</SUB> significantly depends on the atomic orientation axis of MoS<SUB>2</SUB>. </LI> <LI> Flexible piezoelectric NGs were successfully fabricated using the CVD-grown single-crystalline monolayer MoS<SUB>2</SUB> flakes. </LI> <LI> The output power obtained from the NG with the armchair direction of MoS<SUB>2</SUB> is about two times higher than the zigzag direction of MoS<SUB>2</SUB>. </LI> <LI> New effectively harvest mechanical energy using novel flexible piezoelectric NGs based on 2D semiconducting piezoelectric MoS<SUB>2</SUB> for powering low power-consuming devices and realizing self-powered electronics. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>We report directional dependent piezoelectric effects in chemical vapor deposition grown monolayer MoS<SUB>2</SUB> for flexible piezoelectric nanogenerators. The output power obtained from the nanogenerator with the armchair direction of MoS<SUB>2</SUB> is about two times higher than that from the nanogenerator with the zigzag direction of MoS<SUB>2</SUB> under the same strain.</P> <P>[DISPLAY OMISSION]</P>

Automatic Frame Composition Using Histogram Based Graph Cut

Daehee Kim,Hyungtae Kim,Jinho Park,Donggyun Kim,Joonki Paik 보안공학연구지원센터 2015 International Journal of Multimedia and Ubiquitous Vol.10 No.1

In this paper, we present an automatic background composition method using histogram-based graph cut. The proposed method consists of four steps: i) initial label map generation, ii) label map update, iii) object extraction by segmentation, and iv) dynamic background composition. Since the proposed method can minimize the user interaction for generating the initial label map and updating, it is suitable for simple interaction using a low-speed processor and limited memory space. Experimental results show that the proposed method provides better segmentation results compared with existing state-of-the-art methods with significantly reduced computational complexity. The proposed automatic object segmentation and background composition method can be applied to video editing, video conference, and video contents creation using low-cost mobile devices such as smart phones, smart TVs, and tablet PCs.

Improvement of Glucose Uptake Rate and Production of Target Chemicals by Overexpressing Hexose Transporters and Transcriptional Activator Gcr1 in <i>Saccharomyces cerevisiae</i>

Kim, Daehee,Song, Ji-Yoon,Hahn, Ji-Sook American Society for Microbiology 2015 Applied and environmental microbiology Vol.81 No.24

<P>Metabolic engineering to increase the glucose uptake rate might be beneficial to improve microbial production of various fuels and chemicals. In this study, we enhanced the glucose uptake rate in <I>Saccharomyces cerevisiae</I> by overexpressing hexose transporters (HXTs). Among the 5 tested HXTs (Hxt1, Hxt2, Hxt3, Hxt4, and Hxt7), overexpression of high-affinity transporter Hxt7 was the most effective in increasing the glucose uptake rate, followed by moderate-affinity transporters Hxt2 and Hxt4. Deletion of <I>STD1</I> and <I>MTH1</I>, encoding corepressors of <I>HXT</I> genes, exerted differential effects on the glucose uptake rate, depending on the culture conditions. In addition, improved cell growth and glucose uptake rates could be achieved by overexpression of <I>GCR1</I>, which led to increased transcription levels of <I>HXT1</I> and ribosomal protein genes. All genetic modifications enhancing the glucose uptake rate also increased the ethanol production rate in wild-type <I>S. cerevisiae</I>. Furthermore, the growth-promoting effect of <I>GCR1</I> overexpression was successfully applied to lactic acid production in an engineered lactic acid-producing strain, resulting in a significant improvement of productivity and titers of lactic acid production under acidic fermentation conditions.</P>

The Level of Autoantibodies Targeting Eukaryote Translation Elongation Factor 1 α1 and Ubiquitin-Conjugating Enzyme 2L3 in Nondiabetic Young Adults

Kim, Eunhee G.,Kwak, Soo Heon,Hwang, Daehee,Yi, Eugene C.,Park, Kyong Soo,Koo, Bo Kyung,Kim, Kristine M. Korean Diabetes Association 2016 Diabetes and Metabolism Journal Vol.40 No.2

<P><B>Background</B></P><P>The prevalence of novel type 1 diabetes mellitus (T1DM) antibodies targeting eukaryote translation elongation factor 1 alpha 1 autoantibody (EEF1A1-AAb) and ubiquitin-conjugating enzyme 2L3 autoantibody (UBE2L3-AAb) has been shown to be negatively correlated with age in T1DM subjects. Therefore, we aimed to investigate whether age affects the levels of these two antibodies in nondiabetic subjects.</P><P><B>Methods</B></P><P>EEF1A1-AAb and UBE2L3-AAb levels in nondiabetic control subjects (<I>n</I>=150) and T1DM subjects (<I>n</I>=101) in various ranges of age (18 to 69 years) were measured using an enzyme-linked immunosorbent assay. The cutoff point for the presence of each autoantibody was determined based on control subjects using the formula: [mean absorbance+3×standard deviation].</P><P><B>Results</B></P><P>In nondiabetic subjects, there were no significant correlations between age and EEF1A1-AAb and UBE2L3-AAb levels. However, there was wide variation in EEF1A1-AAb and UBE2L3-AAb levels among control subjects <40 years old; the prevalence of both EEF1A1-AAb and UBE2L3-AAb in these subjects was 4.4%. When using cutoff points determined from the control subjects <40 years old, the prevalence of both autoantibodies in T1DM subjects was decreased (EEFA1-AAb, 15.8% to 8.9%; UBE2L3-AAb, 10.9% to 7.9%) when compared to the prevalence using the cutoff derived from the totals for control subjects.</P><P><B>Conclusion</B></P><P>There was no association between age and EEF1A1-AAb or UBE2L3-AAb levels in nondiabetic subjects. However, the wide variation in EEF1A1-AAb and UBE2L3-AAb levels apparent among the control subjects <40 years old should be taken into consideration when determining the cutoff reference range for the diagnosis of T1DM.</P>

Multiple Reaction Monitoring of Multiple Low-Abundance Transcription Factors in Whole Lung Cancer Cell Lysates

Kim, Jun Seok,Lee, Youngju,Lee, Min Young,Shin, Jihye,Han, Jung Min,Yang, Eun Gyeong,Yu, Myeong-Hee,Kim, Sunghoon,Hwang, Daehee,Lee, Cheolju American Chemical Society 2013 Journal of proteome research Vol.12 No.6

<P>Lung cancer-related transcription factors (TFs) were identified by integrating previously reported genomic, transcriptomic, and proteomic data and were quantified by multiple reaction monitoring (MRM) in various cell lines. All experiments were performed without affinity depletion or subfractionation of cell lysates. Since the target proteins were expected to be present in low abundance, we experimentally optimized MRM transition parameters with chemically synthesized peptides. Quantitation was based on stable isotope-labeled standard peptides (SIS peptides). Out of 288 MRM measurements (36 peptides representing 28 TFs × 8 cell lines), 241 were successfully obtained within a quantitation limit of 15 amol, 221 measurements (91.7%) showed coefficients of variation (CVs) of ≤20%, and 149 (61.8%) showed CVs of ≤10%, quantifying as low as 19.4 amol/μg protein for STAT2 with a CV of 6.3% in an A549 cell. Comparisons between MRM measurements and levels of the corresponding mRNAs revealed linear, nonlinear, or no relationship between protein and mRNA levels, indicating the need for an MRM assay. An integrative analysis of MRM and gene expression profiles from doxorubicin-resistant H69AR and sensitive H69 cells further showed that 14 differentially expressed TFs, such as STAT1 and SMAD4, regulated genes associated with drug resistance and cell differentiation-related processes. Thus, the analytical performance of MRM for the quantitation of low abundance TFs suggests its usefulness for biological application.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/jprobs/2013/jprobs.2013.12.issue-6/pr3011414/production/images/medium/pr-2012-011414_0009.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/pr3011414'>ACS Electronic Supporting Info</A></P>

Communication Pattern Based Key Establishment Scheme in Heterogeneous Wireless Sensor Networks

( Daehee Kim ),( Dongwan Kim ),( Sunshin An ) 한국인터넷정보학회 2016 KSII Transactions on Internet and Information Syst Vol.10 No.3

In this paper, we propose a symmetric key establishment scheme for wireless sensor networks which tries to minimize the resource usage while satisfying the security requirements. This is accomplished by taking advantage of the communication pattern of wireless sensor networks and adopting heterogeneous wireless sensor networks. By considering the unique communication pattern of wireless sensor networks due to the nature of information gathering from the physical world, the number of keys to be established is minimized and, consequently, the overhead spent for establishing keys decreases. With heterogeneous wireless sensor networks, we can build a hybrid scheme where a small number of powerful nodes do more works than a large number of resource-constrained nodes to provide enhanced security service such as broadcast authentication and reduce the burden of resource-limited nodes. In addition, an on-demand key establishment scheme is introduced to support extra communications and optimize the resource usage. Our performance analysis shows that the proposed scheme is very efficient and highly scalable in terms of storage, communication and computation overhead. Furthermore, our proposed scheme not only satisfies the security requirements but also provides resilience to several attacks.

Combustion Characteristics of Hydrogen-Enriched Propane in a Dump Combustor with a Bluff-Body

Daehee Kim(김대희),Junggoo Hong(홍정구),Hyundong Shin(신현동),Sangmin Choi(최상민) 한국연소학회 2009 KOSCOSYMPOSIUM논문집 Vol.- No.38

Combustion characteristics of a partially premixed flame in a dump combustor were studied to determine the effects of hydrogen enrichment in propane. A bluff-body was used for flame stabilization. Fuel mixtures of hydrogen mole fraction ranging from 0.1 to 0.5 were burnt at ambient pressure within a quartz chamber. Tests were carried out keeping the total reactants flow rate by adjusting the fuel and air flow rates. Fluctuations of pressure were measured by a piezoelectric pressure sensor. Instantaneous flame structure and OH chemiluminescence images were caprured by a High-speed Intensified Charged Coupled Device (HICCD) camera and Intensified Charged Coupled Device (ICCD) camera. It is shown that hydrogen enrichment in propane induces increase of the frequency and amplitude of pressure fluctuations. Flame existence region seems to be very alike, but instantaneous flame behavior for one cycle showed a different moving tendency according to hydrogen enrichment. Also, location of primary reaction zone was changed from the inner recirculation zone to the turbulent shear layer. The reason is that hydrogen-enriched flame has more fast chemical reaction rate compared to the propane flame so chemical aspects take precedence over flow aspects in the hydrogen-enriched flame.

Electrical conductance change of graphene-based devices upon surface modification for detecting botulinum neurotoxin

Kim, Daehee,Kim, Ho-Jong,Shim, Seung-Bo,Jung, Suyong,Lee, Nam Hee,Nahm, Seung Hoon,Shin, Eui-Cheol,Yun, Wan Soo,Ha, Dong Han Institute of Pure and Applied Physics 2017 Japanese Journal of Applied Physics Vol. No.

<P>We report an electric conductance change in a graphene-based device upon molecular adsorption for detecting botulinum neurotoxin (BoNT) using the antibody-antigen binding strategy. This device consists of a 400-mu m-wide monolayer of graphene between the source and drain electrodes. As-fabricated devices exhibit p-type behaviors. After modifying graphene with linkers and antibodies, BoNT detection was performed by dropping a target solution and measuring the conductance change of the devices. The immobilization of linkers on graphene decreases the electrical conductance as a result of electron transfer from linkers to graphene. However, the conductance change caused by the adsorption of antibodies or BoNTs is ascribed to the top-gating effects of the molecules adsorbed on graphene. The normalized conductance change of the graphene-based device upon antibody-BoNT binding was greater than 5%. (C) 2017 The Japan Society of Applied Physics</P>