Hyper-branched sensing polymer directly constructed on a resonant micro-cantilever for the detection of trace chemical vapor

Liu, Yongjing,Xu, Pengcheng,Yu, Haitao,Zuo, Guomin,Cheng, Zhenxing,Lee, D.-W.,Li, Xinxin The Royal Society of Chemistry 2012 Journal of materials chemistry Vol.22 No.34

<P>A hyper-branched polymer is layer-by-layer self-assembled on a resonant micro-cantilever and, then, functionalized with sensing-terminals for the specific detection of the trace chemical vapor of dimethyl methylphosphonate (DMMP, a typical simulant for nerve agents). The hyper-branched polymer is directly constructed on the SiO<SUB>2</SUB> surface of the cantilever <I>via</I> an A<SUB>2</SUB> + B<SUB>4</SUB> layer-by-layer route, where A<SUB>2</SUB> and B<SUB>4</SUB> are complementary interacting groups which undergo coupled linking. After modification with 4-(2-(4-(allyloxy)phenyl)-1,1,1,3,3,3-hexafluoropropan-2-yl)phenol (APHFPP) groups specific to DMMP, the high specific-surface-area hyper-branched polymer provides very dense sensing sites to adsorb a great number of DMMP molecules for micro-gravimetric detection. Moreover, the sensing polymer possesses a “more branches but fewer roots” configuration on the cantilever surface to depress the cross-talk effect caused by adsorption induced cantilever spring-stiffening. Experimental results indicate that, self-assembled with the hyper-branched sensing polymer, the resonant cantilevers exhibit rapid and reproducible detection of trace DMMP (with the detection limit lower than 7.2 ppb) and effectively depressed parasitic frequency-shift from the cantilever spring stiffening effect. In addition, the sensor features satisfactory selectivity in the presence of water and organic solvents. When an alternative sensing-group of 2-allylhexafluoroisopropanol (AHFIP) is modified on the hyper-branched architecture, the cantilever becomes specifically sensitive to trace explosive vapor. Therefore, the developed technique for the functionalization of hyper-branched polymer directly grown on a cantilever provides a widely usable micro/nano sensing-platform for the detection of trace chemical vapors.</P> <P>Graphic Abstract</P><P>A hyperbranched polymer is directly grafted onto a resonant micro-cantilever surface. The polymer is functionalized with sensing terminal groups and it exhibits the selective, rapid and reproducible detection to trace dimethyl methylphosphonate, with the detection limit lower than 7.2 ppb. <IMG SRC='http://pubs.rsc.org/services/images/RSCpubs.ePlatform.Service.FreeContent.ImageService.svc/ImageService/image/GA?id=c2jm33202g'> </P>

Vibration Characteristics of Cutter-Head in Soft-Hard Mixed Stratum: An Experimental Case Study on Su’ai Tunnel

Zhenxing Yang,Dongjiang Pan,Jianjun Zhou,Jian Chen,Zhenchuan Sun,Haining Liu 대한토목학회 2020 KSCE Journal of Civil Engineering Vol.24 No.4

This paper conducts a simulation experiment research on cutter-head vibration characteristics by evaluating a soft-hard mixed stratum (the upper layer is silty soil, whereas the lower layer is moderately weathered granite of maximum uniaxial compressive strength (UCS) 142.0 MPa and slightly weathered granite of maximum 210.0 MPa). The ratios of hard rock and soil within the tunnel face were designed to be 1:1 and 1:2. Then, the cutter-head and stratum model were subjected to vibration analysis by reasonably deployed accelerometers. Results show that: 1) different conditions of heterogeneous strata mainly affected the acceleration amplitude and frequency distribution of cutter-head, in other words, the stronger hard rock, the larger the strength difference between the hard rock and soil within a tunnel face, the larger the vibration acceleration and the more concentrated the vibration frequency distribution; 2) the radial and circumferential vibration acceleration of the cutter-head in different positions were not largely different; however, axial accelerations were largely different. The axial vibration accelerations first increased and then decreased along the radial direction of cutter-head. Considering the difference between Multi-Mode Boring Test System and real cutter-head structure, the radius of joint between the cutter-head and the flange plate should be reasonably increased according to the ratio of hard rock in tunnel face; 3) with the increasing difference between the strength of the hard rock and soil, the circumferential and axial vibration acceleration multiplied. Thus, the soil remarkably reduces the vibration of the cutter-head. These results can provide some evidence of potential application for advancing manufacturing practice for cutter-head and disc cutter of shield machine.

New 3D 16-Ary Signal Constellations and Their Symbol Error Probabilities in AWGN and Rayleigh Fading Channels

Chen, Zhenxing,Liu, Jiaheng,Li, Shuang,Kang, Seog Geun Hindawi Limited 2018 WIRELESS COMMUNICATIONS AND MOBILE COMPUTING Vol.2018 No.-

<P>Two three-dimensional (3D) 16-ary signal constellations having extended lattice structures are presented in this paper. The theoretical symbol error probabilities (SEPs) of the new constellations in additive white Gaussian noise (AWGN) and Rayleigh fading channel are derived. Computer simulation confirms that the closed-form expressions for average SEPs of the constellations in the AWGN channel are very accurate. The theoretical SEP upper bounds in the Rayleigh fading channel are very tight. Since the presented constellations have larger minimum Euclidean distance (MED) than the conventional one, error performance can be improved up to 0.9 dB in an AWGN environment. Hence, the proposed constellations and their theoretical analysis can be used as a reference for the development of a wireless communication system with 3D signal constellations.</P>

Cyclophosphamide-induced HCN1 channel upregulation in interstitial Cajal-like cells leads to bladder hyperactivity in mice

Qian Liu,Zhou Long,Xingyou Dong,Teng Zhang,Jiang Zhao,Bishao Sun,Jingzhen Zhu,Jia Li,Qingqing Wang,Zhenxing Yang,Xiaoyan Hu,Longkun Li 생화학분자생물학회 2017 Experimental and molecular medicine Vol.49 No.-

Hyperpolarization-activated cyclic nucleotide-gated (HCN) channels are confirmed to be expressed in bladder interstitial Cajal-like cells (ICC-LCs), but little is known about their possible role in cystitis-associated bladder dysfunction. The present study aimed to determine the functional role of HCN channels in regulating bladder function under inflammatory conditions. Sixty female wild-type C57BL/6J mice and sixty female HCN1-knockout mice were randomly assigned to experimental and control groups, respectively. Cyclophosphamide (CYP)-induced cystitis models were successfully established in these mice. CYP treatment significantly enhanced HCN channel protein expression and Ih density and significantly altered bladder HCN1 channel regulatory proteins. Carbachol (CCH) and forskolin (FSK) exerted significant effects on bladder ICC-LC [Ca2+]i in CYP-treated wild-type (WT) mice, and HCN1 channel ablation significantly decreased the effects of CCH and FSK on bladder ICC-LC [Ca2+]i in both naive and CYP-treated mice. CYP treatment significantly potentiated the spontaneous contractions and CCH (0.001–10 μM)-induced phasic contractions of detrusor strips, and HCN1 channel deletion significantly abated such effects. Finally, we demonstrated that the development of CYP-induced bladder overactivity was reversed in HCN1 / mice. Taken together, our results suggest that CYP-induced enhancements of HCN1 channel expression and function in bladder ICC-LCs are essential for cystitis-associated bladder hyperactivity development, indicating that the HCN1 channel may be a novel therapeutic target for managing bladder hyperactivity.

Increased Piezo1 channel activity in interstitial Cajal-like cells induces bladder hyperactivity by functionally interacting with NCX1 in rats with cyclophosphamide-induced cystitis

Qian Liu,Bishao Sun,Jiang Zhao,Qingqing Wang,Fan An,Xiaoyan Hu,Zhenxing Yang,Jie Xu,Mingjia Tan,Longkun Li 생화학분자생물학회 2018 Experimental and molecular medicine Vol.50 No.-

The Piezo1 channel is a mechanotransduction mediator, and Piezo1 abnormalities have been linked to several clinical disorders. However, the role of the Piezo1 channel in cystitis-associated bladder dysfunction has not been documented. The current study aimed to discover the functional role of this channel in regulating bladder activity during cyclophosphamide (CYP)-induced cystitis. One hundred four female rats were randomly assigned to the control, CYP-4h, CYP-48h and CYP-8d groups. CYP successfully induced acute or chronic cystitis in these rats. CYP treatment for 48h or 8d significantly increased Piezo1 channel expression in bladder interstitial Cajal-like cells (ICC-LCs), and the increase in CYP-8d rats was more prominent. In addition, 2.5 μM Grammostola spatulata mechanotoxin 4 (GsMTx4) significantly attenuated bladder hyperactivity in CYP-8d rats by inhibiting the Piezo1 channel in bladder ICCLCs. Furthermore, by using GsMTx4 and siRNA targeting the Piezo1 channel, we demonstrated that hypotonic stressinduced Piezo1 channel activation significantly triggered Ca2+ and Na+ influx into bladder ICC-LCs during CYPinduced chronic cystitis. In addition, the Piezo1 channel functionally interacted with the relatively activated reverse mode of Na+/Ca2+ exchanger 1 (NCX1) in bladder ICC-LCs from CYP-8d rats. In conclusion, we suggest that the functional role of the Piezo1 channel in CYP-induced chronic cystitis is based on its synergistic effects with NCX1, which can significantly enhance [Ca2+]i and result in Ca2+ overload in bladder ICC-LCs, indicating that the Piezo1 channel and NCX1 are potential novel therapeutic targets for chronic cystitis-associated bladder hyperactivity.

Shorter Telomere Length Is Associated with Increased Breast Cancer Risk in a Chinese Han Population: A Case-Control Analysis

Zhaoxia Wang,Zhenxing Zhang,Yanling Guo,Huifeng Shui,Guoqi Liu,Tianbo Jin,Huijie Wang 한국유방암학회 2018 Journal of breast cancer Vol.21 No.4

Purpose: The aim of this study was to investigate the association of telomere length with breast cancer risk. We simultaneously explored the association between telomerase reverse transcriptase gene polymorphisms and telomere length. Methods: We used real-time quantitative polymerase chain reaction to measure relative telomere length (RTL) in genomic DNA extracted from peripheral blood from 183 breast cancer cases and 191 healthy controls. Genotyping was performed using the Sequenom MassARRAY platform. Results: Our results show that breast cancer patients had significantly shorter RTLs than control subjects (p< 0.05). When the RTLs were categorized into tertiles, we found that the lowest RTL was significantly associated with increased breast cancer risk compared with the highest RTL (odds ratio [OR], 2.33; 95% confidence interval [CI], 1.40–3.90; p=0.001). Subgroup analyses indicated that risk of breast cancer was also significantly increased in the lowest RTL compared with the highest RTL in age >40 years (OR, 2.41; 95% CI, 1.31–4.43; p=0.005), body mass index ≤24 kg/m2 (OR, 2.81; 95% CI, 1.55–5.10; p=0.001), and postmenopausal women (OR, 3.94; 95% CI, 1.63–9.51; p=0.002), respectively. In addition, individuals with the AA genotype of rs2853677 have longer telomeres than those of breast cancer patients with the AG genotype (p= 0.011). Conclusion: Our results suggest that shorter RTL was associated with an increased risk of breast cancer. An association was found between the AA genotype of rs2853677 and longer RTLs in the case group. Functional studies are warranted to validate this association and further investigate our findings.

MISFIRE FAULT DIAGNOSIS OF RANGE EXTENDER BASED ON HARMONIC ANALYSIS

Xiaowei Xu,Zhenxing Liu,Jiangdong Wu,Jiaming Xing,Xiaoqing Wang 한국자동차공학회 2019 International journal of automotive technology Vol.20 No.1

For an Extended-Range Electric Vehicle (E-REV), the misfire failure of the range extender can result in working condition deterioration, mileage decrease, vibration and noise increase, and other adverse consequences. The relationship of the shaft instantaneous angular speed (IAS) signal and the misfire fault of the range extender was studied by harmonic analysis. Based on the theory of shafting torsional vibration, the range extender dynamics model was developed to analyze the changing trend of the shaft IAS theoretically. Then, the shaft IAS signal under different working conditions was simulated using a developed range extender rigid-flexible hybrid multi-body dynamics model. It is found that the 0.5-order harmonic phase and the amplitude of range extender IAS can be used as the characteristic parameters in misfire fault diagnosis, which has been verified by experiments on an engine bench.

A GPC-based Multi-variable PID Control Algorithm and Its Application in Anti-swing Control and Accurate Positioning Control for Bridge Cranes

Bin Yang,Zhenxing Liu,Hui-Kang Liu,Yan Li,Sen Lin 제어·로봇·시스템학회 2020 International Journal of Control, Automation, and Vol.18 No.10

It is one of the key tasks for the bridge crane to achieve anti-swing control of the hook and the accurate positioning of the body to work efficiently, safely and automatically. Based on the Lagrange equation, this paper is to propose a dynamic model of the crane motion system for designing controller. In the controller design, ProportionalIntegral-Derivative (PID), the most widely used controller in engineering, is adopted and a new parameter tuning algorithm for a multi-variable PID controller based on generalized predictive control (GPC) is given. It is foundthat the multi-variable PID controller shares the same structural mathematical expressions with the GPC law, which makes for the transfer and calculation of the three parameters P, I and D, and that the new algorithm enables the traditional PID controller to perform as brilliantly as the GPC. The results of both the simulation and real-time control experiments show that the newly-proposed PID controller can effectively eliminate the swing of the hook and control the bridge cranes moving position accurately.

Uplink Achievable Rate analysis of Massive MIMO Systems in Transmit-correlated Ricean Fading Environments

Yixin Xu,Fulai Liu,Zixuan Zhang,Zhenxing Sun 한국인터넷정보학회 2023 KSII Transactions on Internet and Information Syst Vol.17 No.1

In this article, the uplink achievable rate is investigated for massive multiple-input multiple-output (MIMO) under correlated Ricean fading channel, where each base station (BS) and user are both deployed multiple antennas. Considering the availability of prior knowledge at BS, two different channel estimation approaches are adopted with and without prior knowledge. Based on these channel estimations, a two-layer decoding scheme is adopted with maximum ratio precoding as the first layer decoder and optimal second layer precoding in the second layer. Based on two aforementioned channel estimations and two-layer decoding scheme, the exact closed form expressions for uplink achievable rates are computed with and without prior knowledge, respectively. These derived expressions enable us to analyze the impacts of line-of-sight (LoS) component, two-layer decoding, data transmit power, pilot contamination, and spatially correlated Ricean fading. Then, numerical results illustrate that the system with spatially correlated Ricean fading channel is superior in terms of uplink achievable rate. Besides, it reveals that compared with the single-layer decoding, the two-layer decoding scheme can significantly improve the uplink achievable rate performance.

Molybdenum Dioxide-Anchored Graphene Foam as a Negative Electrode Material for Supercapacitors

Xuemei Mu,Xiaozhi Liu,Ke Zhang,Jian Li,Jinyuan Zhou,ER-QING XIE,Zhenxing Zhang 대한금속·재료학회 2016 ELECTRONIC MATERIALS LETTERS Vol.12 No.2

Molybdenum dioxide nanoparticles of diameter 100 nm were anchoreduniformly to a three-dimensional (3D) graphene foam using an ultrasonicationassisteddeposition method. X-ray diffraction and Raman spectroscopyindicated that the molybdenum dioxide nanoparticles had a monoclinic crystalstructure. The 3D graphene/MoO2 nanoparticle composite showed excellentpseudocapacitive ability as its specific capacitance reached 404 F g−1 at a scanrate of 2 mV s−1 in the negative potential range, −1.0 to −0.2 V, in a neutralsolution. Overall, the 3D graphene/MoO2 nanoparticle composite has greatpotential as an anode material for the next generation of high-performancesupercapacitors.