Effects of polymer surface energy on morphology and properties of silver nanowire fabricated via nanoimprint and E-beam evaporation

Zhao, Zhi-Jun,Hwang, Soon Hyoung,Jeon, Sohee,Jung, Joo-Yun,Lee, Jihye,Choi, Dae-Geun,Choi, Jun-Hyuk,Park, Sang-Hu,Jeong, Jun-Ho Elsevier 2017 APPLIED SURFACE SCIENCE - Vol.420 No.-

<P><B>Abstract</B></P> <P>In this paper, we demonstrate that use of different nanoimprint resins as a polymer pattern has a significant effect on the morphology of silver (Ag) nanowires deposited via an E-beam evaporator. RM-311 and Ormo-stamp resins are chosen as a polymer pattern to form a line with dimensions of width (100nm)×space (100nm)×height (120nm) by using nanoimprint lithography (NIL). Their contact angles are then measured to evaluate their surface energies. In order to compare the properties of the Ag nanowires deposited on the various polymer patterns with different surface energies, hydrophobic surface treatment of the polymer pattern surface is implemented using self-assembled monolayers. In addition, gold and aluminum nanowires are fabricated for comparison with the Ag nanowires, with the differences in the nanowire morphologies being determined by the different atomic properties. The monocrystalline and polycrystalline structures of the various Ag nanowire formations are observed using transmission electron microscopy. In addition, the melting temperatures and optical properties of four kinds of Ag nanowire morphologies deposited on various polymer patterns are evaluated using a hot plate and an ultraviolet-visible (UV–vis) spectrometer, respectively. The results indicate that the morphology of the Ag nanowire determines the melting temperature and the transmission. We believe that these findings will greatly aid the development of NIL, along with physical evaporation and chemical deposition techniques, and will be widely employed in optics, biology, and surface wettability applications.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Ag nanowires with various morphologies deposited on polymer patterns with different surface energies were fabricated via nanoimprint and e-beam evaporation. </LI> <LI> The formation mechanism behind the different morphologies of the Ag nanowires deposited on the polymer patterns with different surface energies was explained and confirmed. </LI> <LI> The morphologies of Ag nanowires have an important effect on their transmission and melting temperature. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Modulation of Drug Resistance in Ovarian Cancer Cells by Inhibition of Protein Kinase C-alpha (PKC-α) with Small Interference RNA (siRNA) Agents

Zhao, Li-Jun,Xu, Heng,Qu, Jun-Wei,Zhao, Wan-Zhou,Zhao, Yi-Bing,Wang, Jin-Hua Asian Pacific Journal of Cancer Prevention 2012 Asian Pacific journal of cancer prevention Vol.13 No.8

Objective: To determine whether silence of $PKC-{\alpha}$ expression by small interference RNA (siRNA) might regulate MDR1 expression and reverse chemoresistance of ovarian cancer. Methods: We measured gene and protein expression of MDR1 and $PKC-{\alpha}$ in ovarian cancer cells and assessed their correlation with cell drug resistance. We also examined whether blocking $PKC-{\alpha}$ by RNA interference (RNAi) affected MDR1 expression and reversed drug resistance in drug sensitivity tests. Results: The drug resistance cell lines, OV1228/DDP and OV1228/Taxol, had higher gene and protein expression of MDR1 and $PKC-{\alpha}$ than their counterpart sensitive cell line, OV1228. SiRNA depressed $PKC-{\alpha}$ gene protein expression, as well as MDR1 and protein expression and improved the drug sensitivity in OV1228/DDP and OV1228/Taxol cells. Conclusion: These results indicated that decreasing $PKC-{\alpha}$ expression with siRNA might be an effective method to improve drug sensitivity in drug resistant cells with elevated levels of $PKC-{\alpha}$ and MDR1. A new siRNA-based therapeutic strategy targeting $PKC-{\alpha}$ gene could be designed to overcome the chemoresistance of ovarian cancer.

Macrophages Promote Coal Tar Pitch Extract-induced Tumorigenesis of BEAS-2B Cells and Tumor Metastasis in Nude Mice Mediated by AP-1

Zhang, Peng,Jin, Yue-Fei,Zhang, Qiao,Wu, Yi-Ming,Wu, Wei-Dong,Yao, Wu,Wu, Yong-Jun,Li, Zhi-Tao,Zhao, Yong,Liu, Yu,Feng, Fei-Fei Asian Pacific Journal of Cancer Prevention 2014 Asian Pacific journal of cancer prevention Vol.15 No.12

Background: We sought to evaluate the role of tumor associated macrophages (TAMs) on the promotion of coal tar pitch extract (CTPE)-induced tumorigenesis of human bronchial epithelial cells (BEAS-2B) and tumor metastasis in nude mice, and related mechanisms. Materials and Methods: BEAS-2B cells were first treated with 2.4 mg/mL CTPE for 72 hours. After removal of CTPE, the cells were continuously cultured and passaged using trypsin-EDTA. THP-1 cells were used as macrophage-like cells. BEAS-2B cells under different conditions (n=6/group) were injected into the back necks of nude mice, and alterations of tumor xenograft growth, indicative of tumorigenicity, and tumor metastasis were determined. Pathological changes (tumor nests and microvascular lesions) of HE-stained tumor tissues were also evaluated. The expression of AP-1(c-Jun) in xenografts and metastatic tumors was determined using immunohistochemistry. Results: Tumor size and weight in nude mice transplanted with the mixture of CTPE-induced passage 30 BEAS-2B and THP-1 cells (2:1) were increased compared to those from the CTPE-treated BEAS-2B cells at passage 30 alone at different observation time points. Tumor metastasis to lymph nodes and liver was only detected after transplantation of a mixture the two kinds of cells. The numbers of tumor nests and microvascular lesions, and the expression levels of AP-1 (c-Jun) in tumors from the mixture of two kinds of cells were increased apparently in contrast to those in tumor from the CTPE-treated BEAS-2B cells of passage 30 alone. In addition, there was positive correlation between AP-1 (c-Jun) expression level and the number of microvascular lesions, or between AP-1 (c-Jun) expression level and tumor metastasis in these two groups. Conclusions: TAMs not only facilitate tumorigenesis transformation of CTPE-induced BEAS-2B cells, but also promote tumor growth, angiogenesis and metastasis in nude mice in vivo, which may be mediated by AP-1.

Modeling and damage detection for cracked I-shaped steel beams

Zhao, Jun,DeWoIf, John T. Techno-Press 2007 Structural Engineering and Mechanics, An Int'l Jou Vol.25 No.2

This paper presents the results of a study to show how the development of a crack alters the structural behavior of I-shaped steel beams and how this can be used to evaluate nondestructive evaluation techniques. The approach is based on changes in the dynamic behavior. An approximate finite element model for a cracked beam with I-shaped cross-section is developed based on a simplified fracture model. The model is then used to review different damage cases. Damage detection techniques are studied to determine their ability to identify the existence of the crack and to identify its location. The techniques studied are the coordinate modal assurance criterion, the modal flexibility, and the state and the slope arrays.

The Efficacy of Aspirin in Preventing the Recurrence of Colorectal Adenoma: a Renewed Meta-Analysis of Randomized Trials

Zhao, Tai-Yun,Tu, Jing,Wang, Yin,Cheng, Da-Wei,Gao, Xian-Kui,Luo, Hao,Yan, Bi-Chun,Xu, Xiao-Li,Zhang, Hong-Ling,Lu, Xing-Jun,Wang, Yao-Jun Asian Pacific Journal of Cancer Prevention 2016 Asian Pacific journal of cancer prevention Vol.17 No.5

Background: Through search the possible randomized control trials, we make a renewed meta-analysis in order to assess the impact of aspirin in preventing the recurrence of colorectal adenoma. Materials and Methods: The Medicine/PubMed, Embase, Cochrane Central Register of Controlled Trials (CENTRAL), Chinese biomedical literature service system (SinoMed) databases were searched for the related randomized controlled trials until to the April 2016. Three different authors respectively evaluated the quality of studies and extracted data, and we used the STATA software to analyze, investigate heterogeneity between the data, using the fixed-effects model to calculate and merge data. Results: 7 papers were included the renewed meta-analysis, among these studies, two pairs were identified as representing the same study population, with the only difference being the duration of follow-up. Thus there were only five papers included our meta-analysis, and one Chinese paper were also included the work. Results were categorized by the length of follow-up, different kinds of people, varied dose of oral aspirin. The relative of adenoma in patients taking aspirin vs placebo were 0.73 (95% CI 0.55-0.98, P=0.039) with 1 year follow up; 0.84 (95% CI 0.72-0.98, P=0.484) with greater than 1 year follow up; for the advanced adenoma, the RR 0.68 (95% CI 0.49-0.94, P=0.582),for one year; RR=0.75 (95% CI 0.52-1.07, P=0.552) for greater one year. Furthermore the white population could divided into two subgroups according to the different length of follow-up time. When the length of follow-up time less than 3-year, The RR of two subgroups respective were RR=0.86 (95% CI 0.76-0.98, P=0.332), $I^2=0%$, RR=0.68 (95% CI 0.47-0.98, P=0.552), $I^2=64.6%$, But with the extension of follow-up time greater than 2-year, with the white, oral aspirin without considering dose had no efficacy on preventing the recurrence of any adenoma, the RR was 0.86 (95% CI 0.71-1.05, P=0.302), $I^2=16.4%$. Conclusions: This meta-analysis indicated that oral aspirin is associated with a remarkable decrease in the recurrence of any adenoma and advanced adenomas in patients follow-up for 1 year without concerning the dose of aspirin, but with the extension of follow-up time for greater than 1 year, oral aspirin can be effective on preventing the recurrence of any adenoma, but for the advanced adenoma, the result indicated that oral aspirin had no efficacy, According to the inclusion of ethnic groups, we also divided relevant papers into two subgroups as the yellow and white group. Then the follow-up time was less than 3 years, oral aspirin without considering the dose, had an significant efficacy on preventing the recurrence of any adenoma. But with the follow-up greater than 2 years, oral aspirin had no effect in the white.

Attenuation of Beryllium Induced Hepatorenal Dysfunction and Oxidative Stress in Rodents by Combined Effect of Gallic Acid and Piperine

Jun-Quan Zhao,Guo-Zhen Du,You-Cai Xiong,Yi-Fu Wen,Monika Bhadauria,Satendra Kumar Nirala 대한약학회 2007 Archives of Pharmacal Research Vol.30 No.12

We determined a minimum effective dose of gallic acid (3,4,5-trihydroxy benzoic acid; 50 mg/ kg, i.p.) and piperine (10 mg/kg, p.o.) through their therapeutic potential and further evaluated them individually and in combination against beryllium-induced biochemical alterations and oxidative stress consequences in female albino rats. The administration of beryllium altered blood biochemical variables by significantly depleting hemoglobin, albumin and urea, whereas it enhanced bilirubin and creatinine. The release of serum transaminase, lactate dehydrogenase and γ-glutamyl transpeptidase was significantly greater, and was concomitant with a decrease in serum alkaline phosphatase. A significant increase in lipid peroxidation and a decrease in glutathione, superoxide dismutase and catalase in the liver and kidney was an indication of oxidative stress due to beryllium exposure. Individual administration of gallic acid and piperine moderately reversed the altered biochemical variables, whereas the combination of these was found to completely reverse the beryllium-induced biochemical alterations and oxidative stress consequences. We concluded that gallic acid exerts a synergistic effect when administered with piperine and provides a more pronounced therapeutic potential in reducing beryllium-induced hepatorenal dysfunction and oxidative stress consequences.

Power t distribution

Zhao, Jun,Kim, Hyoung-Moon The Korean Statistical Society 2016 Communications for statistical applications and me Vol.23 No.4

In this paper, we propose power t distribution based on t distribution. We also study the properties of and inferences for power t model in order to solve the problem of real data showing both skewness and heavy tails. The comparison of skew t and power t distributions is based on density plots, skewness and kurtosis. Note that, at the given degree of freedom, the kurtosis's range of the power t model surpasses that of the skew t model at all times. We draw inferences for two parameters of the power t distribution and four parameters of the location-scale extension of power t distribution via maximum likelihood. The Fisher information matrix derived is nonsingular on the whole parametric space; in addition we obtain the profile log-likelihood functions on two parameters. The response plots for different sample sizes provide strong evidence for the estimators' existence and unicity. An application of the power t distribution suggests that the model can be very useful for real data.

The Application of Computer Simulation to Flexible Spacecraft Dynamics

Zhao Jun,Xiao You Zhang,Yong De Jin 대한전자공학회 1995 ICEIC:International Conference on Electronics, Inf Vol.1 No.1

Key Factors Affecting Sustainable Economic Growth in the New Normal Era: An Empirical Analysis of Country Data

Jun Zhao,이서영 한국무역학회 2024 Journal of Korea trade Vol.28 No.3

Purpose – The global economy has entered a new normal era since the financial crisis of 2007 and 2008. In fact, advanced countries and those emerging have been faced with low growth, low interest rates, low prices, high unemployment, increased government debt, and stricter regulations. Nonetheless, some countries have achieved sustainable economic growth. We attempted to identify factors influencing sustainable economic growth in this era by empirically testing a model with data regarding economic indicators in 25 countries. Design/Methodology – For this empirical test, a panel model was set with nine economic variables for 14 advanced and 11 emerging countries. We conducted both a panel unit root test and a cointegration test in order to measure the stationarity of the data. The results of these tests presented that there have been long-term balanced relationships among the variables. We also conducted another empirical analysis through the fixed effects model and random effects model, and performed a Hausman test to confirm that the fixed effects model was more valid. Findings – Empirical evidence using the fixed effects model showed that the consumption level, capital formation, openness of international trade, urbanization, and innovation ability were significant in promoting the economic development of developed countries, whereas population has a negative impact on the economic development of these countries. In emerging economies, capital formation and education level had a positive effect on sustainable economic growth. Population, openness to international trade, urbanization, and industrial structure had negative impacts on sustainable economic growth. This research contained a certain level of originality in the sense that we analyzed the effects of critical economic indicators on the sustainable economic growth in representative countries that have developed economically in the new normal era. Originality/value – Few studies focus on the inf luencing factors of sustainable economic development in a specific country. We may provide important implications for economic policy makers that want to grow their economies sustainably. We also may enrich a theoretical and practical basis on economic development.

Eight Inch Wafer-Scale Flexible Polarization-Dependent Color Filters with Ag-TiO₂ Composite Nanowires

Zhao, Zhi-Jun,Lee, Minpyo,Kang, Hyeokjung,Hwang, SoonHyoung,Jeon, Sohee,Park, Namkyoo,Park, Sang-Hu,Jeong, Jun-Ho American Chemical Society 2018 ACS APPLIED MATERIALS & INTERFACES Vol.10 No.10

<P>In this study, 8 in. wafer-scale flexible polarization-dependent color filters with Ag-TiO<SUB>2</SUB> composite nanowires have been fabricated using nanoimprint and E-beam evaporation. The filters change their color via a simple rotation of the polarizer. In addition, the color of the filter can be controlled by altering the thickness of the Ag and TiO<SUB>2</SUB> nanowires deposited on the polymer patterns. Polarization-dependent color filters were realized by selective inhibition of transmission using the plasmonic resonance at the insulator/metal/insulator nanostructure interface, which occurs at particular wavelengths for the transverse magnetic polarizations. Special colors, including purple, blue, green, yellow, and pink, could be obtained with high transmission beyond 65% by varying the thickness of the deposited Ag and TiO<SUB>2</SUB> nanowires on the periodic polymer pattern under transverse magnetic polarization. In addition, a continuous color change was achieved by varying the polarization angle. Last, numerical simulations were implemented in comparison with the experimental results, and the mechanism was explained. We believe that this simple and cost-effective method can be applied to processes such as anticounterfeiting and holographic imaging as well as to color displays.</P> [FIG OMISSION]</BR>