Flexible and transparent strain sensor made with silver nanowire–coated cellulose

Mun, Seongcheol,Zhai, Lindong,Min, Seung-Ki,Yun, Youngmin,Kim, Jaehwan SAGE Publications 2016 Journal of intelligent material systems and struct Vol.27 No.8

<P>Simple and versatile method of layer-by-layer deposition is used to coat silver nanowire on a cellulose film to fabricate a flexible and transparent strain sensor. Strain-sensing behaviors of such a simply fabricated cellulose film are analyzed in both stretching and bending modes. When 0.01wt% silver nanowire is coated on the cellulose film, 70% transmittance is maintained with 2.4 k Omega/sq of sheet resistance, which is applicable for transparent electrode of the strain sensor. Conductivity of the transparent electrode is maintained after mechanical stretching, which demonstrates that the silver nanowire coating is securely adhered on the surface of cellulose film. The strain sensor shows high strain sensitivity and good gauge factor maintaining good transparency at low silver nanowire concentration, which might be associated with the tunneling resistance change in the silver nanowire. The morphology of the silver nanowire-coated cellulose strain sensor is investigated using an atomic force microscopy with an increase in silver nanowire concentration.</P>

A lithium–oxygen battery based on lithium superoxide

Lu, Jun,Jung Lee, Yun,Luo, Xiangyi,Chun Lau, Kah,Asadi, Mohammad,Wang, Hsien-Hau,Brombosz, Scott,Wen, Jianguo,Zhai, Dengyun,Chen, Zonghai,Miller, Dean J.,Sub Jeong, Yo,Park, Jin-Bum,Zak Fang, Zhigang Nature Publishing Group, a division of Macmillan P 2016 Nature Vol.529 No.7586

<P>Batteries based on sodium superoxide and on potassium superoxide have recently been reported(1-3). However, there have been no reports of a battery based on lithium superoxide (LiO2), despite much research(4-8) into the lithium-oxygen (Li-O-2) battery because of its potential high energy density. Several studies(9-16) of Li-O-2 batteries have found evidence of LiO2 being formed as one component of the discharge product along with lithium peroxide (Li2O2). In addition, theoretical calculations have indicated that some forms of LiO2 may have a long lifetime(17). These studies also suggest that it might be possible to form LiO2 alone for use in a battery. However, solid LiO2 has been difficult to synthesize in pure form(18) because it is thermodynamically unstable with respect to disproportionation, giving Li2O2 (refs 19, 20). Here we show that crystalline LiO2 can be stabilized in a Li-O-2 battery by using a suitable graphene-based cathode. Various characterization techniques reveal no evidence for the presence of Li2O2. A novel templating growth mechanism involving the use of iridium nanoparticles on the cathode surface may be responsible for the growth of crystalline LiO2. Our results demonstrate that the LiO2 formed in the Li-O-2 battery is stable enough for the battery to be repeatedly charged and discharged with a very low charge potential (about 3.2 volts). We anticipate that this discovery will lead to methods of synthesizing and stabilizing LiO2, which could open the way to high-energy-density batteries based on LiO2 as well as to other possible uses of this compound, such as oxygen storage.</P>

Stability of a Class of Switched Stochastic Nonlinear Systems under Asynchronous Switching

Yu Kang,Dihua Zhai,Ping Zhao,Yun-Bo Zhao 제어·로봇·시스템학회 2012 International Journal of Control, Automation, and Vol.10 No.6

The stability of a class of switched stochastic nonlinear retarded systems with asynchronous switching controller is investigated. By constructing a virtual switching signal and using the average dwell time approach incorporated with Razumikhin-type theorem, the sufficient criteria for pth moment exponential stability and global asymptotic stability in probability are given. It is shown that the stability of the asynchronous stochastic systems can be guaranteed provided that the average dwell time is sufficiently large and the mismatched time between the controller and the systems is suffi-ciently small. This result is then applied to a class of switched stochastic nonlinear delay systems where the controller is designed with both state and switching delays. A numerical example illustrates the effectiveness of the obtained results.

Characterization method of rolling bearing operation state based on feature information fusion

Ning Li,Xianghe Yun,Qingkai Han,Baogang Wen,Jingyu Zhai 대한기계학회 2023 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.37 No.3

Aiming at the problem of incomplete information covered by the bearing state discrimination using a single physical quantity as the data source, a characterization method based on the feature information fusion of multi-physical quantities including acceleration RMS and stiffness that are sensitive to the bearing operating state is proposed. The accelerated life test of the bearing is carried out through the bearing experiment bench, and the effect of different feature information fusion schemes to characterize the bearing state is compared, and the effectiveness of the method is verified. This paper also analyzes the different characteristics of the state evolution law between the bearing early failure caused by specific factors and the bearing reaching normal fatigue life, which provides a new method and idea for the maintenance strategy of rolling bearing such as condition-based maintenance.

Targeted Silencing of Inhibitors of Apoptosis Proteins with siRNAs: A Potential Anti-cancer Strategy for Hepatocellular Carcinoma

Li, Gang,Chang, Hong,Zhai, Yun-Peng,Xu, Wei Asian Pacific Journal of Cancer Prevention 2013 Asian Pacific journal of cancer prevention Vol.14 No.9

Hepatocellular carcinoma (HCC) is one of the most common malignancies, with a very poor prognosis. Despite significant improvements in diagnosis and treatment in recent years, the long-term therapeutic efficacy is poor, partially due to tumor metastasis, tecurrence, and resistance to chemo-or radio-therapy. Recently, it was found that a major feature of tumors is a combination of unrestrained cell proliferation and impaired apoptosis. There are now 8 recogized members of the IAP-family: NAIP, c-IAP1, c-IAP2, XIAP, Survivin, Bruce, Livin and ILP-2. There proteins all contribute to ingibition of apoptosis, and provide new potential avenues of cancer treatment. As a powerful tool to suppress gene expression in mammalian cells, RNAi species for inhibiting IAP genes cab be directed against cancers. This review will provide a brief introduction to recent developments of the application IAP-siRNA in tumor studies, with the aim of inspiring future treatment of HCC.

HPLC Determination of Malondialdehyde in ECV304 Cell Culture Medium for Measuring the Antioxidant Effect of Vitexin-4"-O-glucoside

Xi-xiang Ying,Hai-bo Li,Zheng-yun Chu,Yan-jun Zhai,Ai-jing Leng,Xun Liu,Wen-jie Zhang,Ting-guo Kang,Chun Xin 대한약학회 2008 Archives of Pharmacal Research Vol.31 No.7

To investigate the antioxidant effect of vitexin-4"-O-glucoside, a flavone glycoside, isolated from the leaves of Crataegus pinnatifida Bge. var. major, we developed a simple and sensitive high-performance liquid chromatography (HPLC) method to determine levels of malondialdehyde (MDA) in ECV304 cell culture medium after induction by tert-butyl-hydroperoxide (TBHP). The preparation of analyzed samples involved a one-step derivatization with thiobarbituric acid (TBA). HPLC analysis was performed on a SynergiTM Hydro-RP, a polar end-capped C18 column (250×4.6 mm, 4 μm), using an acetonitrile-ammonium acetate aqueous solution (10 mM, pH 6.8) as the mobile phase under linear gradient conditions with UV detection at 532 nm. The calibration curve was linear over 0.0125-1.25 μM MDA (r = 0.9951). Relative standard deviations (RSDs) of intra-day and inter-day precision were less than 6.1% and 5.0%, respectively. The mean recovery was 96.9 ± 1.6%. The lower limit of quantification (LLOQ) of MDA was 0.0125 μM. This chromatographic method was successfully applied to investigating the in vitro antioxidant effect of vitexin-4"-O-glucoside. Vitexin-4"-O-glucoside (120 M) protected ECV304 cells from peroxidation induced by TBHP.

Impact of Co-transfection with Livin and Survivin shRNA Expression Vectors on Biological Behavior of HepG2 Cells

Xu, Wei,Chang, Hong,Qin, Cheng-Kun,Zhai, Yun-Peng Asian Pacific Journal of Cancer Prevention 2013 Asian Pacific journal of cancer prevention Vol.14 No.9

Objective: To construct short hairpin RNA (shRNA) eukaryotic expression vectors targeting Livin and Survivin genes, and to explore the impact of co-transfection of Livin and Survivin shRNA expression vectors on the biological behavior of HepG2 cells. Methods: shRNA eukaryotic expression vectors pSD11-Livin and pSD11-Survivin were designed and constructed then transfected into HepG2 cells separately or in combination. mRNA and protein expression in transfected cells was assessed by quantitative fluorescence PCR and Western blotting, respectively. Cell proliferation was measured by MTT assay and cell apoptosis by TUNEL assay. Results: The Livin and Survivin shRNA eukaryotic expression vectors were successfully constructed and transfected into HepG2 cells. The relative mRNA expression levels of Livin and Survivin in HepG2 cells co-transfected with pSD11-Livin and pSD11-Survivin were $0.12{\pm}0.02$ and $0.33{\pm}0.13$, respectively, which was significantly lower than levels in cells transfected with either pSD11-Livin or pSD11-Survivin (P<0.05). The relative protein expression levels of Livin and Survivin in the co-transfected cells were also significantly decreased compared to single-transfection (P<0.05). The inhibition rate of cell growth in the co-transfection group was higher than that in the single-transfection groups at 48 h, 60 h, or 72 h after transfection (P<0.01). The apoptotic rate increased to the greatest extent in the co-transfection group relative to any other group (P<0.05). Conclusions: Co-transfection with pSD11-Livin and pSD11-Survivin was more efficient than transfection with either vector alone in reducing the mRNA and protein expression of Livin and Survivin genes in HepG2 cells. Co-transfection also inhibited the proliferation of transfected cells more than the other groups, and induced cellular apoptosis more effectively.

Eastern Staining: A Simple Recombinant Protein Detection Technology Using a Small Peptide Tag and Its Counter Partner Which is a Fluorescent Compound

Lee, Jae-Jung,Kim, Jun-Young,Zhai, Duanting,Yun, Seong-Wook,Chang, Young-Tae Korean Society for Bioinformatics 2012 Interdisciplinary Bio Central (IBC) Vol.4 No.2

Small peptide tags such as c-myc, HA, or FLAG tag have facilitated efficient Western-blotting of proteins of interest especially when specific antibodies for the proteins are not available. However, the conventional Western-blotting requires the multi-steps process taking at least several hours up to two days. With examples of various applications, here we show a convenient and time-saving method for protein detection which employs a fluorescent chemical BDED and its binding peptide RC-tag. And we propose "Estern staining", as a standard term for protein detection method using fluorescent chemicals and their binding small peptide tags. Eastern staining may substitutes for the time-consuming "immuno-staining" in many versatile applications.

Comparison of diapause and non-diapause induced Orius sauteri (Hemiptera: Anthocoridae) based on a two-sex life table in the laboratory

Meng Sun,Bing Lü,Zhao-yun Lyu,Yang Zhang,Yi-Fan Zhai,Hao Chen,Li Zheng,Yi Yu 한국응용곤충학회 2017 Journal of Asia-Pacific Entomology Vol.20 No.4

The flower bug Orius sauteri (Poppius) is commonly used as an effective biocontrol agent for controlling small pest populations in greenhouses in China. The impact of two temperature and photoperiod regimes (26 °C, L16:D8 h; 21 °C, L8:D16 h) on the life table of O. sauteri was studied in the laboratory using an age-stage, two-sex life-table method. The results showed that the low-temperature short-photoperiod regime resulted in significant increases of the developmental times of the egg, the first to fifth nymphal stages, and the total preadult stage. Female adult longevity was significantly increased, whereas male adult longevity was significantly decreased, under this regime. Furthermore, the adult preoviposition period (APOP), the total preoviposition period (TPOP), and the sex ratio were all increased under this regime. Fecundity decreased, whereas the mean generation time (T) increased, as temperature and photoperiod decreased. The intrinsic rate of increase (r), finite rate of increase (λ), and net reproductive rate (Ro) all increased as the temperature decreased under diapause induction. Based on the estimated data, the higher r value (0.06 d−1) occurred under the 26 °C, L16:D8 h regime, compared with 0.03 d−1, under the 21 °C, L8:D16 h regime. Thus, the results showed that reproductive diapause slowed O. sauteri population growth, about 50% reduction based on r. There is significant interest in using O. sauteri as a biological control agent against non-diapausing small pests, such as thrips, in greenhouses under short photoperiods. However, based on the current results, managers should consider maintaining a high temperature and long photoperiod to prevent reproductive diapause induction in O. sauteri. Such conditions should not have a detrimental effect on the greenhouse crops

Effect of Wet Spinning and Stretching to Enhance Mechanical Properties of Cellulose Nanofiber Filament

Hyun Chan Kim,Debora Kim,Ji Yun Lee,Lindong Zhai,Jaehwan Kim 한국정밀공학회 2019 International Journal of Precision Engineering and Vol.6 No.3

Long filament made with nanocellulose has been researched due to its eminent mechanical and physical properties for next generation of natural fiber reinforced polymer composites. Wet spinning process for long filament fabrication in conjunction with stretching method has advantages of high efficiency and low-cost. To fabricate homogeneous and strong cellulose nanofiber filament, this paper experimentally investigates the process parameters, including spinning speed, pre-dry temperature and inner diameter of needle. In addition to the spinning process, a mechanical stretching process is taken into account to further improve the mechanical properties of the cellulose nanofiber filament. The effects of wet spinning and stretching are evaluated by using scanning electron microscope, tensile test and 2D wide angle X-ray diffraction. As a result, the stretched cellulose nanofiber filament exhibits its Young’s modulus of 37.5 GPa and tensile strength of 543.1 MPa, which are significantly improved from the previous reports. All about the fabrication process, characterization and evaluation of the cellulose nanofiber filaments are illustrated.