A Novel Hybrid Random Copolymer Poly(MAPOSS-co-NIPAM-co-OEGMA-co-2VP): Synthesis, Characterization, Self-Assembly Behaviors and Multiple Responsive Properties

Yiting Xu,Jianjie Xie,Lingnan Chen,Conghui Yuan,Yinyin Pan,Ling Cheng,Weiang Luo,Birong Zeng,Lizong Dai 한국고분자학회 2013 Macromolecular Research Vol.21 No.12

A novel organic/inorganic hybrid amphiphilic random copolymer poly(methacrylate isobutyl POSS-co-N-isopropylacrylamide-co-oligo(ethylene glycol) methyl ether methacrylate-co-2-vinylpyridine), poly(MAPOSS-co-NIPAM-co-OEGMA-co-2VP), was synthesized via reversible addition-fragmentation chain transfer (RAFT) polymerization. The self-assembly behavior of random copolymers in aqueous solution was investigated by dynamic light scattering (DLS) as well as transmission electron microscopy (TEM). The results indicate the novel random copolymer in water could self-assemble into spherical aggregates and the self-aggregate size displays a remarkable dependence on pH. The stimuli-responsive characteristics of these assembles were tested by means of UV-vis spectra,DLS and TEM. There is a critic Zn2+ concentration over which the aggregates can be coordinated into well-define spherical aggregate clusters. The critic Zn2+ concentration can be tuned finely through adjusting solution concentration or 2VP amount. Results from UV-vis and DLS reveal that the copolymer solutions exhibit a sharp and intensive lower critical solution temperature (LCST). Some factors such as the solution concentration, molecular weight, pH and copolymer generation, which could affect the cloud point, were studied systematically. The essentially predetermined LCST can be achieved by altering the content of 2VP or pH. In addition, these novel hybrid aggregates can undergo an association/disassociation cycle with the heating and cooling of solution and the degree of reversibility shows a strong concentration dependence. As a novel organic-inorganic hybrid material which can respond to multiple external stimuli including temperature, pH, metal ions with sharp stimuli-responsive behaviors, it is potentially used for biomedicine, catalysis, diagnostics, bioseparations, biosensors and for fundamental investigation.

Interpenetration Enhancing of Chitosan-PEGLM Double Network (DN) Hydrogel and Its Properties

Yiting Xu,Jianjie Xie,Hui Gao,Ying Cao,Min Chen,Yanling Liu,Birong Zeng,Feng-Chih Chang,Lizong Dai 한국고분자학회 2015 Macromolecular Research Vol.23 No.1

A series of polylactic acid-polyethylene glycol-polylactic acid diacrylate macromers (PEGLM) were synthesized,and a novel chitosan-PEGLM double network (DN) hydrogel was further successfully fabricated by thesequential interpenetrating technology with highly cross-linked chitosan as the rigid component and PEGLM as theflexible component. Their structures and components were characterized by 1H NMR, FTIR, and XRD. Their fracturemorphology was investigated by SEM. It was interesting to found that the compressive strength of hydrogel woundreach its maximum value when the chitosan content was 10%, no matter what the molecular weight of PEGLM componentwas. What’s more, we found that the compressive strength of 6KL7 could reach 1.07 MPa at gel state, whosePEG segment molecular weight was 6,000, and polymerization degree of PLA was 7. The effects of glutaraldehyderatio, polymerization degree of PLA, and molecular weight of PEG segment on the mechanical strength of DNhydrogels were also discussed in this article. To further strengthen DN hydrogels, the double network-linear (DNL)hydrogels were fabricated by introducing linear poly(vinyl alcohol) (PVA) into the DN hydrogels. The DN-Lhydrogels exhibited better mechanical properties, with the compressive strength up to 1.45 MPa. These hydrogelsmay have prospective applications in the fields of wound dressing, artificial cartilage and tissue engineering scaffoldmaterials which require high mechanical properties.

A Novel Hybrid Polyhedral Oligomeric Silsesquioxane-Based Copolymer with Zwitterion: Synthesis, Characterization, Self-Assembly Behavior and pH Responsive Property

Yiting Xu,Jiamei Huang,Yuntong Li,Meijie Wang,Ying Cao,Conghui Yuan,Birong Zeng,Lizong Dai 한국고분자학회 2017 Macromolecular Research Vol.25 No.8

A novel zwitterionic hybrid amphiphilic copolymer containing polyhedral oligomericsilsesquioxane (POSS), and poly(methacrylate isobutyl POSS)-b-poly (3-dimethyl(methacryloyloxyethyl) ammonium propane sulfonaten-co-2-(diethylamino) ethyl methacrylate-co-styrene) (PMAiBuPOSS-b-P(DMAPS-co-DMAEMAco- St)), was prepared by the ring open reaction of 1, 3-propane sultone with tertiary amine on the precursor polymer. This hybrid copolymer could self-assemble into spherical micelle with a relatively narrow size distribution. The micelle size exhibited a great dependence on pH, as the size of the micelles was of evidently decreases with the increase of the pH value. Controllable release of pyrene from the micelles was investigated by fluorescent emission spectra. Micelles with more zwitterionic units would lead to less pyrene release and longer equilibrium time. The protein adsorption resistance of the micelles was tested by mixing them with fetal bovine serum. The antifouling ability was improved by increasing the number of zwitterionic units as well as decreasing the number of DMAEMA units. This novel hybrid amphiphilic random copolymer with the pH-responsive and anti-protein-fouling ability, can be potentially used for drug carriers for controlled release.

Downregulation of HuR Inhibits the Progression of Esophageal Cancer through Interleukin-18

Xu Xiaohui,Song Cheng,Chen Zhihua,Yu Chenxiao,Wang Yi,Tang Yiting,Luo Judong 대한암학회 2018 Cancer Research and Treatment Vol.50 No.1

Purpose The purpose of this study was to investigate the effect of human antigen R (HuR) downregulation and the potential target genes of HuR on the progression of esophageal squamous cell carcinoma (ESCC). Materials and Methods In this study, a proteomics assay was used to detect the expression of proteins after HuR downregulation, and a luciferase assay was used to detect the potential presence of a HuR binding site on the 3’-untranslated region (3'-UTR) of interleukin 18 (IL-18). In addition, colony formation assay, MTT, EdU incorporation assay, Western blot, flow cytometry, immunohistochemistry, transwell invasion assay, and wound healing assay were used. Results In the present study, we found that the expression of both HuR protein and mRNA levels were higher in tumor tissues than in the adjacent tissues. HuR downregulation significantly suppressed cell proliferation. In addition, the metastasis of esophageal cancer cells was inhibited, while the expression of E-cadherin was increased and the expression of matrix metalloproteinase (MMP) 2, MMP9, and vimentin was decreased after HuR knockdown. Moreover, silencing of HuR disturbed the cell cycle of ESCC cells mainly by inducing G1 arrest. Furthermore, proteomics analysis showed that downregulation of HuR in TE-1 cells resulted in 100 upregulated and 122 downregulated proteins, including IL-18 as a significantly upregulated protein. The expression of IL-18 was inversely regulated by HuR. IL-18 expression was decreased in ESCC tissues, and exogenous IL-18 significantly inhibited the proliferation and metastasis of ESCC cells. The 3'-UTR of IL-18 harbored a HuR binding site, as shown by an in vitro luciferase assay. Conclusion HuR plays an important role in the progression of esophageal carcinoma by targeting IL-18, which may be a potential therapeutic target for the treatment of ESCC.

A Novel Method for Dynamic Gesture Recognition

Wenkai Xu,Yiting Shang,Eung-Joo Lee 한국멀티미디어학회 2011 한국멀티미디어학회 국제학술대회 Vol.2011 No.-

In this paper, we propose an automatic system that recognizes both continuous gestures and isolated in real-time, including Arabic numbers (0-9), alphabets (A-Z). We present a new method to get skin-color segmentation based on mixing nonlinear YCbCr elliptic cluster skill-color model and HSI skin-color segmentation model; then an improved HMM-FNN model is proposed for gesture recognition. The algorithm we present have the best performance and achieves average rate recognition 95.76% and 93.64% for Arabic Numbers and Alphabets, respectively.

A Novel Experimental Measurement Method of Transformer Parasitic Capacitances

Naizeng Wang,Xu Yang,Angyang Zhou,Yiting Xie 전력전자학회 2019 ICPE(ISPE)논문집 Vol.2019 No.5

As the increase of switching frequency and the extensive use of planar transformers, the capacitive effects of transformers can’t be neglected anymore. Firstly, several transformer parasitic capacitance models are introduced in this paper. Next, this paper proposes a novel experimental method, charge balance method, to measure transformer parasitic capacitances. This method is applicable to single lumped parasitic capacitance model. Finally, the step response method is performed to verify the charge balance method. Experimental results show that the charge balance method is of high accuracy.

$H_{\infty}$ filter for flexure deformation and lever arm effect compensation in M/S INS integration

Liu, Xixiang,Xu, Xiaosu,Wang, Lihui,Li, Yinyin,Liu, Yiting The Society of Naval Architects of Korea 2014 International Journal of Naval Architecture and Oc Vol.6 No.3

On ship, especially on large ship, the flexure deformation between Master (M)/Slave (S) Inertial Navigation System (INS) is a key factor which determines the accuracy of the integrated system of M/S INS. In engineering this flexure deformation will be increased with the added ship size. In the M/S INS integrated system, the attitude error between MINS and SINS cannot really reflect the misalignment angle change of SINS due to the flexure deformation. At the same time, the flexure deformation will bring the change of the lever arm size, which further induces the uncertainty of lever arm velocity, resulting in the velocity matching error. To solve this problem, a $H_{\infty}$ algorithm is proposed, in which the attitude and velocity matching error caused by deformation is considered as measurement noise with limited energy, and measurement noise will be restrained by the robustness of $H_{\infty}$ filter. Based on the classical "attitude plus velocity" matching method, the progress of M/S INS information fusion is simulated and compared by using three kinds of schemes, which are known and unknown flexure deformation with standard Kalman filter, and unknown flexure deformation with $H_{\infty}$ filter, respectively. Simulation results indicate that $H_{\infty}$ filter can effectively improve the accuracy of information fusion when flexure deformation is unknown but non-ignorable.

A Dual-scale Network with Spatial-temporal Attention for 12-lead ECG Classification

Shuo Xiao,Yiting Xu,Chaogang Tang,Zhenzhen Huang 한국인터넷정보학회 2023 KSII Transactions on Internet and Information Syst Vol.17 No.9

The electrocardiogram (ECG) signal is commonly used to screen and diagnose cardiovascular diseases. In recent years, deep neural networks have been regarded as an effective way for automatic ECG disease diagnosis. The convolutional neural network is widely used for ECG signal extraction because it can obtain different levels of information. However, most previous studies adopt single scale convolution filters to extract ECG signal features, ignoring the complementarity between ECG signal features of different scales. In the paper, we propose a dual-scale network with convolution filters of different sizes for 12-lead ECG classification. Our model can extract and fuse ECG signal features of different scales. In addition, different spatial and time periods of the feature map obtained from the 12-lead ECG may have different contributions to ECG classification. Therefore, we add a spatial-temporal attention to each scale sub-network to emphasize the representative local spatial and temporal features. Our approach is evaluated on PTB-XL dataset and achieves 0.9307, 0.8152, and 89.11 on macro-averaged ROC-AUC score, a maximum F1 score, and mean accuracy, respectively. The experiment results have proven that our approach outperforms the baselines.

H∞ filter for flexure deformation and lever arm effect compensation in M/S INS integration

Xixiang Liu,Xiaosu Xu,Lihui Wang,Yiting Liu 대한조선학회 2014 International Journal of Naval Architecture and Oc Vol.6 No.3

On ship, especially on large ship, the flexure deformation between Master (M)/Slave (S) Inertial Naviga-tion System (INS) is a key factor which determines the accuracy of the integrated system of M/S INS. In engineering this flexure deformation will be increased with the added ship size. In the M/S INS integrated system, the attitude error between MINS and SINS cannot really reflect the misalignment angle change of SINS due to the flexure deformation. At the same time, the flexure deformation will bring the change of the lever arm size, which further induces the uncertainty of lever arm velocity, resulting in the velocity matching error. To solve this problem, a H∞ algorithm is proposed, in which the attitude and velocity matching error caused by deformation is considered as measurement noise with limited energy, and measurement noise will be restrained by the robustness of H∞ filter. Based on the classical “attitude plus velocity” matching method, the progress of M/S INS information fusion is simulated and compared by using three kinds of schemes, which are known and unknown flexure deformation with standard Kalman filter, and unknown flexure deformation with H∞ filter, respectively. Simulation results indicate that H∞ filter can effectively improve the accuracy of information fusion when flexure deformation is unknown but non-ignorable.

Heteroatoms in situ-doped hierarchical porous hollow-activated carbons for high-performance supercapacitor

Yan Rui,Wang Kai,Tian Xiaodong,Li Xiao,Yang Tao,Xu Xiaotong,He Yiting,Lei Shiwen,Song Yan 한국탄소학회 2020 Carbon Letters Vol.30 No.3

Heteroatoms in situ-doped hierarchical porous hollow-activated carbons (HPHACs) have been prepared innovatively by pyrolyzation of setaria viridis combined with alkaline activation for the frst time. The micro-morphology, pore structure, chemical compositions, and electrochemical properties are researched in detail. The obtained HPHACs are served as outstand�ing electrode materials in electrochemical energy storage ascribe to the particular hierarchical porous and hollow structure, and the precursor setaria viridis is advantage of eco-friendly as well as cost-efective. Electrochemical measurement results of the HPHACs electrodes exhibit not only high specifc capacitance of 350 F g−1 at 0.2 A g−1, and impressive surface specifc capacitance (Cs) of 49.9 μF cm−2, but also substantial rate capability of 68% retention (238 F g−1 at 10 A g−1) and good cycle stability with 99% retention over 5000 cycles at 5 A g−1 in 6 M KOH. Besides, the symmetrical supercapacitor device based on the HPHACs electrodes exhibits excellent energy density of 49.5 Wh kg−1 at power density of 175 W kg−1 , but still maintains favorable energy density of 32.0 Wh kg−1 at current density of 1 A g−1 in 1-ethy-3-methylimidazolium tetrafuoroborate (EMIMBF4) ionic liquid electrolyte, and the excellent cycle stability behaviour shows the nearly 97% ratio capacitance retention of the initial capacitance after 10,000 cycles at current density of 2 A g−1. Overall, the results indicate that HPHACs derived from setaria viridis have appealing electrochemical performances thus are promising electrode materi�als for supercapacitor devices and large-scale applications.