Sensing formic acid with a water-based chitosan lanthanide luminescence film

Xu Zheng,Xi Chen,Xudong Yu,Yifan Yang 한국공업화학회 2023 Journal of Industrial and Engineering Chemistry Vol.125 No.-

A sensitive and selective formic acid sensor could be useful in detecting this corrosive acid in industrial,medical, and environmental settings. Herein, we present a film for detection of formic acid. We introducedchitosan as a film-forming factor to creatively overcome the problem that chitosan dissolves inacids. A carboxylic acid-carbon dot solution was used to replace the strong acid solution and prepare aluminescent film in which the color changed from green to blue when it was exposed to formic acid. Integrated data analysis of the film was used to distinguish vapor from formic acid/water solutions at differentconcentrations and with a detection limit of 0.01% v/v. The selectivity of the sensor was also investigated. After fumigation with ethanol and other common solvents, there was no response similar to thatfor formic acid. It is believed that films based on lanthanide complexes and chitosan could prevent corrosionand injury from formic acid.

Monitoring and control of wind-induced vibrations of hanger ropes of a suspension bridge

Xu G. Hua,Zheng Q. Chen,Xu Lei,Qin Wen,Hua W. Niu 국제구조공학회 2019 Smart Structures and Systems, An International Jou Vol.23 No.6

In August 2012, during the passage of the typhoon Haikui (1211), large amplitude vibrations were observed on long hangers of the Xihoumen suspension Bridge, which destroyed a few viscoelastic dampers originally installed to connect a pair of hanger ropes transversely. The purpose of this study is to identify the cause of vibration and to develop countermeasures against vibration. Field measurements have been conducted in order to correlate the wind and vibration characteristics of hangers. Furthermore, a replica aeroelastic model of prototype hangers consisting of four parallel ropes was used to study the aeroelastic behavior of hanger ropes and to examine the effect of the rigid spacers on vibration mitigation. It is shown that the downstream hanger rope experiences the most violent elliptical vibration for certain wind direction, and the vibration is mainly attributed to wake interference of parallel hanger ropes. Based on wind tunnel tests and field validation, it is confirmed that four rigid spacers placed vertically at equal intervals are sufficient to suppress the wake-induced vibrations. Since the deployment of spacers on hangers, server hanger vibrations and clash of hanger ropes are never observed.

Association Between the Ku70-1310C/G Promoter Polymorphism and Cancer Risk: a Meta-analysis

Xu, Lu,Ju, Xiao-Bing,Li, Pu,Wang, Jue,Shi, Zhu-Mei,Zheng, Ming-Jie,Xue, Dan-Dan,Xu, Yan-Jie,Yin, Yong-Mei,Wang, Shui,You, Yong-Ping Asian Pacific Journal of Cancer Prevention 2012 Asian Pacific journal of cancer prevention Vol.13 No.2

Ku70 plays an important role in DNA double-strand break repair. Studies revealing conflicting results on the role of the Ku70-1310C/G promoter polymorphism on cancer risk led us to perform a meta-analysis to investigate this relationship. Ten case-control studies with 2566 cases and 3058 controls were identified. Odds ratios (ORs) and 95% confidence intervals (CIs) were used to assess the strength of associations. The overall results suggested no association between the Ku70-1310C/G promoter polymorphism and total cancer risk. However, on stratified analysis, significantly increased risks were observed among the Asian population (GG vs. CC: OR=1.50, 95%CI=1.10-2.06; GG vs. CC/CG: OR=1.47, 95%CI=1.07-2.01) and population-based case-control studies (GG vs. CC: OR=1.57, 95%CI=1.12-2.22; CG vs. CC: OR=1.35, 95%CI=1.11-1.64; CG/GG vs. CC: OR=1.37, 95%CI=1.14-1.65). Additionally, variant genotypes were associated with a significantly increased breast cancer risk (GG vs. CC: OR=1.80, 95%CI=1.26-2.56; GG vs. CC/CG: OR=1.40, 95%CI=1.01-1.95).

Effects of Modified MMT on Mechanical Properties of EVA/MMT Nanocomposites and Their Foams

Xu, Zheng Run,Park, Hae Youn,Kim, Ho Young,Seo, Kwan Ho WILEY-VCH Verlag 2008 Macromolecular symposia Vol.264 No.1

<P>In this study, nanocomposites of poly(ethylene-co-vinyl acetate) with two kinds of organically modified montmorillonite (OMMT) were prepared by melt intercalation. Their structures and mechanical properties were characterized by X-ray diffraction (XRD) and tensile test respectively. Especially, foaming of these nanocomposites mixed with chemical blowing agent was carried out through compression molding. Influences of OMMT on foaming ratio and mechanical properties were investigated by density test, tensile test and tear test. Results revealed that both kinds of OMMT with proper content increased tensile strength and Young's modulus of nanocomposites without a compromise of elongation at break. For foaming, OMMTs apparently improved foaming ratio and in particular, one of them can improve tear strength, tensile strength, Young's modulus and elongation although the density was decreased.</P>

A bis(pyridine-2-ylmethyl)amine-based selective and sensitive colorimetric and fluorescent chemosensor for Cu²⁺

Zheng, Xu,Lee, Kum Hee,Liu, Hongguang,Park, So-Young,Yoon, Seung Soo,Lee, Jin Yong,Kim, Yang-Gyun Elsevier 2016 Sensors and actuators. B Chemical Vol.222 No.-

<P><B>Abstract</B></P> <P>A new bis(pyridine-2-ylmethyl)amine derivative (<B>1</B>) was synthesized as a colorimetric and fluorescent chemosensor for metal ions. Experimental results indicate that <B>1</B> displays significant colorimetric and fluorescent changes upon binding of Cu<SUP>2+</SUP>. Since <B>1</B> has a high water solubility as well as good cell-permeability, it successfully applied to detect the presence of Cu<SUP>2+</SUP> ion in HepG2 cells in culture medium. Thus, <B>1</B> can be used as a potential Cu<SUP>2+</SUP> chemosensor in aqueous solution and mammalian cells. Further, the fluorescence behavior of <B>1</B> upon Cu<SUP>2+</SUP> binding was well explained by our quantum calculation based on electronic structure.</P>

Refolding Behavior of Urea-Induced Denaturation Collagen

Xu Wei,Yanqiu Zhao,Jingjing Zheng,Qin Cao,Sheng Li,Lang He,Benmei Wei,Juntao Zhang,Chengzhi Xu,Haibo Wang 한국고분자학회 2021 Macromolecular Research Vol.29 No.6

Exploration of the denaturation and refolding of natural collagen is important for the application of collagen and its denatured products. In this study, using urea as a denaturant, we prepared a denatured natural collagen product and analyzed its structural changes. The denaturation treatment severely destroyed the triple helix conformation of collagen, but had no significant effect on the primary structure of its α chains or the covalent cross-linking between α chains. Next, we observed the refolding behavior of the denatured collagen by removing urea through dialysis. We found that the denatured collagen products from different sources (grass carp skin, bovine tendon) all showed a reconstruction of the triple helix conformation up to 60-75% of the value of natural collagen during the refolding process. The telopeptide did not significantly promote triple helix reconstruction. In conclusion, the reconstruction of the α chains did not perfectly occur in a “head-to-head, tail-to-tail” manner in refolded collagen, as each α chain was participating in the reconstruction of multiple triple helix domains. The refolded collagen still had weak self-assembly ability and formed a unique network-like structure containing small interlaced and closely combined fibers, which shows favorable cell compatibility and potential applications.

Structure and function of Zalpha, a Z conformation-specific nucleic acid binding domain

Xu Zheng,Chan Yang Park,So-Young Park,Jinhyuk Choi,Yang-Gyun Kim 한국구조생물학회 2015 Biodesign Vol.3 No.4

Right-handed B-DNA is a predominant form of natural DNA and used for the structural support of genetic information. Nevertheless, DNA can assume many different shapes. Left-handed Z-DNA is one of well-known non-B-DNA structures. An increasing number of studies show direct connections between Z-DNA and its potent roles in biological processes. The discovery of the proteins with Z-DNA binding domain(s), Zα, provides new opportunities to elucidate the relevant biological function of Z-DNA in biological systems. Thus, a great deal of recent researches has focused on questions surrounding Z-DNA and its binding proteins in vivo. In this review, we compare structures of Zα domains from various Z-DNA binding proteins and discuss their conformational specificity adapted from the common fold that prevalently used by many B-DNA binding proteins. In addition, we summarize recent developments regarding the biological roles of Z-DNA and Z-DNA binding proteins.

Corroded pipeline failure analysis using artificial neural network scheme

Xu, Wen-Zheng,Li, Chun Bao,Choung, Joonmo,Lee, Jae-Myung Elsevier Applied Science 2017 Advances in engineering software Vol.112 No.-

<P><B>Abstract</B></P> <P>Corrosion defects occur very often on the internal and external surfaces of pipelines, which may result in a serious threat to the integrity of the pipelines. Numerous studies investigated failure behavior of corroded pipelines with single corrosion defects. However, few studies focus on interacting corrosion defects. Interacting defects are defined as defects with certain proximity that interact to reduce the overall strength of a pipeline. In the present study, the failure behavior of pipelines with interacting corrosion defects was studied using a finite element method, and then a solution was proposed to predict burst pressure using an artificial neural network. The solution was validated by experimental results in previous studies and compared with other existing assessment solutions to prove its applicability and efficiency.</P> <P><B>Highlights</B></P> <P> <UL> <LI> The failure behavior of pipelines with interacting corrosion defects was studied using FE method. </LI> <LI> A series of models were created for the sensitive study of the various parameters. </LI> <LI> A solution was proposed to predict burst pressure using an artificial neural network (ANN). </LI> <LI> The solution was validated by comparing with experimental results and existing codes. </LI> </UL> </P>

A New Neolignan Glycoside from Pteris multifida Poir.

Xu-dong Zheng*,Hao-bin Hu,Huai-sheng Hu 대한화학회 2008 Bulletin of the Korean Chemical Society Vol.29 No.6

Inter‑turn short‑circuit fault detection with high‑frequency signal injection for inverter‑fed PMSM systems

Zheng Xu,Jianzhong Zhang,Zakiud Din,Yongbin Wu,Ming Cheng 전력전자학회 2023 JOURNAL OF POWER ELECTRONICS Vol.23 No.6

This paper develops an online inter-turn short-circuit fault (ISF) detection method for inverter-fed permanent magnet synchronous machine (PMSM) systems. A high-frequency (HF) mathematical model of a PMSM with an ISF is established. Based on the presented HF model, the HF responses of the PMSM with various severity of ISF under HF voltage injectionare analyzed in detail, where both the short-circuit ratio and the fault resistance are considered to evaluate the fault severity. In the proposed fault diagnosis method, the amplitude of the HF negative-sequence component is used to determine the fault severity, and the initial phase is used to locate the position of the faulty phase. The simulation and experimental results verify the effectiveness of the proposed method.