43 results on '"Chen, Xingxing"'
Search Results
2. An Intrinsic Photothermal Supramolecular Hydrogel with Robust Mechanical Strength and NIR‐Responsive Shape Memory.
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Wang, Ruyue, Chen, Xingxing, Cheng, Yilong, Ding, Zicheng, Ming, Xiaoqing, and Zhang, Yanfeng
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TENSILE strength , *PHOTOTHERMAL effect , *YOUNG'S modulus , *ETHYLENE glycol , *SHAPE memory polymers - Abstract
Near‐infrared (NIR)‐triggered shape memory hydrogels with promising mechanical strength hold immense potential in the field of biomedical applications and soft actuators. However, the optical and mechanical properties of currently reported hydrogels usually suffer from limited solubility and dispersion of commonly used photothermal additives in hydrogels, thus restricting their practical implementations. Here,, a set of NIR‐responsive shape memory hydrogels synthesized by polyaddition of diisocyanate‐terminated poly(ethylene glycol), imidazolidinyl urea (IU), and p‐benzoquinone dioxime (BQDO) is reported. The introduction of IU, a hydrogen bond reinforcing factor, significantly enhances the mechanical properties of the hydrogels, allowing for their tunable ranges of the ultimate tensile strength (0.4–2.5 MPa), elongation at break (210–450%), and Young's modulus (190–850 kPa). The unique hydrogels exhibit an intrinsic photothermal effect because of the covalently incorporated photothermal moiety (BQDO), and the photothermal supramolecular hydrogel shows controllable shape memory capabilities characterized by rapid recovery speed and high recovery ratio (>90%). This design provides new possibilities for applying shape memory hydrogels in the field of soft actuators. [ABSTRACT FROM AUTHOR]
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- 2024
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3. Covalent Adaptable Networks with Dual Dynamic Covalent Bonds for Self‐Repairing Infrared Transmitting Materials.
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Cui, Chenhui, Wang, Fang, Chen, Xingxing, Xu, Ting, Li, Zhen, Chen, Kexiang, Guo, Yinzhou, Cheng, Yilong, Ge, Zhishen, and Zhang, Yanfeng
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COVALENT bonds ,LIPOIC acid ,INFRARED equipment ,RING-opening polymerization ,MONOMERS ,EPOXY resins ,POLYMER networks - Abstract
Infrared transmitting materials (IRTMs) are prone to mechanical and corrosion damage during long‐time exposure to harsh outside environments. However, conventional IRTMs frequently lack self‐repairability that limit their lifespan. To address the limitation, thioctic acid‐based epoxy resins (TAEs) are developed from natural thioctic acid and commercial epoxy monomers. The double ring‐opening polymerization (ROP) reactions of thioctic acid and epoxy groups result in dual dynamic covalent bonds with varying bond energies containing relatively weak disulfide bonds and strong ester bonds. As compared with conventional covalent adaptable networks (CANs) that present rapid creep properties when heated, TAEs maintain their geometric stability during rapid self‐repairing at a mild temperature of 80 °C by enhancing network integrity through stable ester crosslinking points. The feature renders TAEs self‐repairing capability while maintaining precise geometrical dimensions, which is suitable for infrared transmitting devices. On the other hand, TAEs exhibit high near‐infrared transmittance (>80%). Therefore, TAEs with self‐repairability and high infrared transmittance demonstrate they can be used as superior polymeric IRTM. [ABSTRACT FROM AUTHOR]
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- 2024
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4. Cross‐species signaling pathways analysis inspire animal model selections for drug screening and target prediction in vascular aging diseases.
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Sun, Fei, Chen, Xingxing, Zhang, Shuqing, Jiang, Haihong, Chen, Tianhong, Xing, Tongying, Li, Xueyi, Sultan, Rabia, Wang, Zhimin, and Jia, Jia
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CELLULAR signal transduction , *AGE factors in disease , *ANIMAL models in research , *VASCULAR diseases , *DRUG therapy - Abstract
Age is a significant contributing factor to the occurrence and progression of cardiovascular disease (CVD). Pharmacological treatment can effectively alleviate CVD symptoms caused by aging. However, 90% of the drugs have failed in clinics because of the loss of drug effects or the occurrence of the side effects. One of the reasons is the disparity between animal models used and the actual physiological levels in humans. Therefore, we integrated multiple datasets from single‐cell and bulk‐seq RNA‐sequencing data in rats, monkeys, and humans to identify genes and pathways with consistent/differential expression patterns across these three species. An approach called "Cross‐species signaling pathway analysis" was developed to select suitable animal models for drug screening. The effectiveness of this method was validated through the analysis of the pharmacological predictions of four known anti‐vascular aging drugs used in animal/clinical experiments. The effectiveness of drugs was consistently observed between the models and clinics when they targeted pathways with the same trend in our analysis. However, drugs might have exhibited adverse effects if they targeted pathways with opposite trends between the models and the clinics. Additionally, through our approach, we discovered four targets for anti‐vascular aging drugs, which were consistent with their pharmaceutical effects in literatures, showing the value of this approach. In the end, software was established to facilitate the use of "Cross‐species signaling pathway analysis." In sum, our study suggests utilizing bioinformatics analysis based on disease characteristics can help in choosing more appropriate animal models. [ABSTRACT FROM AUTHOR]
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- 2024
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5. Constructing Singlet Oxygen "Slow Release" Platform to Optimize the Performance of Commercial Photosensitizers.
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Ni, Yingyong, Wang, Junjun, Ai, Wenming, Yu, Zhipeng, Zhu, Xiaojiao, Wang, Sen, Sun, Xianshun, Zhang, Qiong, Chen, Xingxing, Zhu, Manzhou, and Zhou, Hongping
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REACTIVE oxygen species ,PHOTOSENSITIZERS ,PHOTODYNAMIC therapy ,CHEMICAL processes ,LASER beam cutting ,MASS spectrometry - Abstract
Commercial photosensitizers (PSs) present great potential in the field of clinical photodynamic therapy (PDT) yet face a formidable challenge owing to the extremely short lifespan of singlet oxygen (1O2). Herein, the 1O2 slow‐release "platform" is proposed based on an anthracene‐groups functionalized D‐π‐A system (AIC), which can capture and slowly release 1O2 produced by commercial PSs. Meanwhile, the reversible chemical process between AIC and 1O2 is demonstrated by a series of optical experiments and high‐resolution mass spectrum. Remarkably, by virtue of 1O2 slow‐release "platform", the sustaining mitochondrial autophagy and cell apoptosis still take place when the laser is cut off with a short period of irradiation, reducing the side effect of sustained irradiation. In general, the construction of 1O2 slow‐release platform opens up exciting opportunities for improving the PDT effect of commercial PSs. [ABSTRACT FROM AUTHOR]
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- 2024
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6. MFAP2 promotes HSCs activation through FBN1/TGF‐β/Smad3 pathway.
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Sun, Yonghong, Chen, Xingxing, Chen, Lili, Bao, Baixin, Li, Chunming, and Zhou, Yongning
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HEPATIC fibrosis ,GENE expression ,LIVER cells ,CARBON tetrachloride ,EXTRACELLULAR matrix ,FIBROSIS - Abstract
Liver fibrosis is a chronic inflammatory process characterized by the accumulation of extracellular matrix (ECM), which contributes to cirrhosis and hepatocellular carcinoma. Increasing evidence suggests that the activation of hepatic stellate cells (HSCs) under an inflammatory state leads to the secretion of collagens, which can cause cirrhosis. In this study, we analysed data from the Gene Expression Omnibus (GEO) databases to identify differentially expressed genes (DEGs) between quiescent and fibrotic HSCs. We found that Microfibril Associated Protein 2 (MFAP2) was elevated in carbon tetrachloride (CCl4)‐induced liver fibrosis and Transforming Growth Factor‐Beta 1 (TGF‐β1)‐activated HSCs. Knockdown of MFAP2 inhibited HSC proliferation and partially attenuated TGF‐β‐stimulated fibrogenesis markers. Bioinformatics analysis revealed that Fibrillin‐1 (FBN1) was correlated with MFAP2, and the expression of FBN1 was significantly upregulated after MFAP2 overexpression. Silencing MFAP2 partially attenuated the activation of HSCs by inhibiting HSC proliferation and decreasing collagen deposits. In vitro results showed that the inhibition of MFAP2 alleviated hepatic fibrosis by inhibiting the activation and inducing the apoptosis of active HSCs in a CCl4‐induced mouse model. In conclusion, our results suggest that MFAP2 is a potential target for the clinical treatment of liver fibrosis. [ABSTRACT FROM AUTHOR]
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- 2023
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7. Study on Mechanism and Thermodynamics of NO Absorption by Acetylcholine‐chloride Type Deep Eutectic Solvents.
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Xiao, Xinxin, Liu, Yixuan, Chen, Xingxing, Bai, Hongcun, Xu, Xiuli, Yu, Jianglong, and Dou, Jinxiao
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EUTECTICS ,CHEMICAL shift (Nuclear magnetic resonance) ,NUCLEAR magnetic resonance spectroscopy ,THERMODYNAMICS ,FOURIER transform infrared spectroscopy ,ABSORPTION ,FLUE gases - Abstract
NO absorption by using deep eutectic solvents (DESs) from flue gas has become one of great research interest. In this work, different DESs were prepared with acetylcholine chloride as a hydrogen‐bond acceptor. The effect of molar ratio of the hydrogen‐bond acceptor and different hydrogen‐bond donor, temperature, and different hydrogen‐bond donors on NO absorption by acetylcholine chloride DESs was investigated systematically. The absorption experiment of NO by acetylcholine‐methyl urea DES at an absorption capacity of 0.119 (g NO/g DES) when the molar ratio of acetylcholine chloride to methyl urea was 1 : 2 at 30–40 °C. The absorption mechanism of NO by acetylcholine chloride DESs was determined by Fourier transform infrared spectroscopy and 1H nuclear magnetic resonance combined with quantum chemical calculation. The results indicated that NO with acetylcholine‐methyl urea DESs by chemical absorption to form NONO structure, nitrogen‐oxygen double bonds (N=O), nitrogen‐oxygen single bonds (N−O), and nitrogen‐nitrogen single bonds (N−N). The simulation results showed that nitric oxide formed two hydrogen bonds with N atoms on methyl urea: C−N⋅⋅⋅N and O=N⋅⋅⋅N=O. Thermodynamic properties showed that the ▵rHom for NO absorption in acetylcholine‐chloride‐type DES was −15.39 kJ/mol, which was more efficient for NO absorption/desorption. [ABSTRACT FROM AUTHOR]
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- 2023
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8. Small‐signal modelling considering internal perturbations for modular multilevel converters.
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Song, Shuguang, Liu, Jinjun, Chen, Xingxing, Sheng, Junyi, and Liu, Hanjun
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TRANSFER functions ,VOLTAGE control ,MULTILEVEL models ,ELECTRIC transients - Abstract
Small‐signal modelling of modular multilevel converters (MMC) has drawn lots of attention recently. Existing research mainly studies MMC terminal impedances by injecting corresponding AC‐side and DC‐side external small‐signal perturbations. This paper focuses on the MMC internal small‐signal perturbations, that is, perturbations in control signal and their effect. There are two kinds, that is, differential‐mode and common‐mode, of internal small‐signal perturbations, which influence MMC external and internal state variables, respectively. Then, the existing MMC small‐signal model is improved. With its help, accurate MMC control‐signal to state‐variables transfer functions are established, which can aid precise MMC controller analysis and performance optimization. In this paper, an analysis of MMC phase capacitor voltage regulation control is demonstrated as an example. The stability can be precisely ascertained based on the obtained transfer function. The effect of parameter variation of the proportional‐integral controller is also studied. Moreover, an additional compensator is introduced in the existing control loop to attenuate resonance peaks in the transfer function, which mitigates the large voltage overshoot and makes the transient state much smoother. Simulation and experimental results support and well confirm the analysis of this paper. [ABSTRACT FROM AUTHOR]
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- 2023
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9. Synthesis of a Coal Fly Ash‐Based NaP Zeolite Using the Microwave‐Ultrasonic Assisted Method: Preparation, Growth Mechanism, and Kinetics.
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Liu, Yixuan, Zhou, Tengteng, Chen, Xingxing, Li, Hua, Xu, Xiuli, Dou, Jinxiao, and Yu, Jianglong
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ZEOLITES ,COAL ,CRYSTAL growth ,FLY ash ,CRYSTAL structure - Abstract
Fly ash was used as the raw material to prepare coal fly ash‐based NaP zeolite using the microwave‐ultrasonic‐hydrothermal method. The obtained NaP zeolite has a completed crystal structure, regular surface morphology, uniform particle size (about 1.6 um), large specific surface area (48.85 m2/g) and good thermal stability. Under microwave and ultrasonic external fields, the coal fly ash‐based NaP zeolite crystals grow in an S‐shape, achieving single crystal growth and uniform crystal growth size. The activation energy of NaP zeolite crystal growth Ea is 2.08 kJ/mol, the pre‐exponential factor A is 85.63. [ABSTRACT FROM AUTHOR]
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- 2023
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10. Operation Mechanism of n‐Type Organic Electronic Metabolite Sensors.
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Druet, Victor, Nayak, Prem D., Koklu, Anil, Ohayon, David, Hama, Adel, Chen, Xingxing, Moser, Maximilian, McCulloch, Iain, and Inal, Sahika
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ELECTROLYTE analysis ,DETECTORS ,SEMICONDUCTOR devices ,HYDROGEN peroxide ,PHENOMENOLOGICAL theory (Physics) ,CALCIUM channels - Abstract
The integration of n‐type (electron‐transporting) polymers with oxidase enzymes has allowed building high‐performance organic electrochemical transistor (OECT) based metabolite sensors. Yet, the operation mechanism of these devices is poorly understood. Here, the process is investigated for the conversion of metabolite oxidation to electrical current in an n‐type organic electrochemical transistor (n‐OECT). By monitoring oxygen (O2), hydrogen peroxide, and pH changes in the electrolyte as well as the potential of each electrical contact of the n‐OECT during glucose detection, light is shed on the physical phenomena occurring at the polymer‐enzyme interface. It is shown that the n‐type film performs O2 reduction reaction in its doped state and that the n‐OECT characteristics are sensitive to O2. A correlation is found between the consumption of electrolyte‐dissolved O2 and the generation of n‐OECT current during the metabolite oxidation. The results demonstrate how the sensitivity of a polymer to O2, species known to deteriorate the performance of many semiconductor devices, becomes a feature to exploit in sensor applications. The importance of in operando analysis of the electrolyte composition and the terminal potentials is highlighted for understanding the operation mechanism of bioelectronic devices and for sensor design and materials development. [ABSTRACT FROM AUTHOR]
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- 2022
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11. Molecular subtypes predict second breast events of ductal carcinoma in situ after breast‐conserving surgery.
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Yang, Yilan, Zhao, Xu, Wang, Xuanyi, Jin, Kairui, Luo, Jurui, Yang, Zhaozhi, Mei, Xin, Ma, Jinli, Shao, Zhimin, Zhang, Zhen, Chen, Xingxing, Guo, Xiaomao, and Yu, Xiaoli
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LUMPECTOMY ,CARCINOMA in situ ,DUCTAL carcinoma ,EPIDERMAL growth factor receptors ,PROPORTIONAL hazards models - Abstract
Purpose Currently, the prognostic value of molecular subtypes in ductal carcinoma in situ (DCIS) remains unclear. In this study, we explored whether molecular subtypes could predict second breast events (SBEs) in patients after breast‐conserving surgery (BCS). Methods: From January 2008 to December 2016, 291 DCIS patients treated with BCS were retrospectively analyzed. Patients were classified into four molecular subtypes: luminal A, luminal B, human epidermal growth factor receptor 2 (HER2) overexpression, and triple‐negative breast cancer (TNBC). The SBE incidence was calculated by the competing risk model and compared by Gray's test. The disease‐free survival rates were estimated by the Kaplan–Meier method and compared by the log‐rank test. Prognostic factors were evaluated by univariate and multivariate COX proportional hazards regression model. Results: With a median follow‐up of 66 months, 12 SBEs were identified. The 5‐year overall SBE incidence of luminal A, luminal B, HER2 overexpression, and TNBC was 2.18%, 4.25%, 15.15%, and 0.00%, respectively. In the univariate analysis, the HER2 overexpression subtype was the predictor of overall (p = 0.005), in situ (p = 0.004), and ipsilateral SBEs (p = 0.008). Patients with endocrine therapy were less likely to develop in situ SBEs (p = 0.039). Additionally, patients with closed (<2 mm) or involved margins were related to a higher risk of contralateral SBEs (p = 0.029). In the multivariate analysis, the HER2 overexpression subtype remained of prognostic values for overall (p = 0.006), in situ (p = 0.029), and ipsilateral SBEs (p = 0.012). Conclusions: The molecular subtype, especially the HER2 overexpression subtype, was the independent prognostic factor for DCIS patients who underwent BCS. [ABSTRACT FROM AUTHOR]
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- 2022
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12. Lactone Backbone Density in Rigid Electron‐Deficient Semiconducting Polymers Enabling High n‐type Organic Thermoelectric Performance.
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Alsufyani, Maryam, Stoeckel, Marc‐Antoine, Chen, Xingxing, Thorley, Karl, Hallani, Rawad K., Puttisong, Yuttapoom, Ji, Xudong, Meli, Dilara, Paulsen, Bryan D., Strzalka, Joseph, Regeta, Khrystyna, Combe, Craig, Chen, Hu, Tian, Junfu, Rivnay, Jonathan, Fabiano, Simone, and McCulloch, Iain
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SPINE ,BISMUTH telluride ,POLYMERS ,ELECTRIC conductivity ,ACTIVATION energy ,ELECTRON affinity ,MAGNITUDE (Mathematics) - Abstract
Three lactone‐based rigid semiconducting polymers were designed to overcome major limitations in the development of n‐type organic thermoelectrics, namely electrical conductivity and air stability. Experimental and theoretical investigations demonstrated that increasing the lactone group density by increasing the benzene content from 0 % benzene (P‐0), to 50 % (P‐50), and 75 % (P‐75) resulted in progressively larger electron affinities (up to 4.37 eV), suggesting a more favorable doping process, when employing (N‐DMBI) as the dopant. Larger polaron delocalization was also evident, due to the more planarized conformation, which is proposed to lead to a lower hopping energy barrier. As a consequence, the electrical conductivity increased by three orders of magnitude, to achieve values of up to 12 S cm and Power factors of 13.2 μWm−1 K−2 were thereby enabled. These findings present new insights into material design guidelines for the future development of air stable n‐type organic thermoelectrics. [ABSTRACT FROM AUTHOR]
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- 2022
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13. Postoperative radiotherapy improves overall survival in patients with primary squamous cell carcinoma of the breast.
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Wang, Xuanyi, Zhang, Li, Luo, Jurui, Jin, Kairui, Yang, Zhaozhi, Meng, Jin, Zhang, Xiaomeng, Zhang, Zhen, Shao, Zhimin, Guo, Xiaomao, Chen, Xingxing, and Yu, Xiaoli
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OVERALL survival ,SQUAMOUS cell carcinoma ,SURVIVAL rate ,PROGNOSIS ,CANCER invasiveness ,BREAST self-examination - Abstract
Background: Primary squamous cell carcinoma of the breast (PSCCB) is a rare clinical classification of breast tumors. Little is known about its clinicopathological features, prognosis and potential therapeutic strategies. The purpose of this study is to evaluate the effect of postoperative radiotherapy (PORT) on patients with squamous cell carcinoma (SCC) of the breast. Methods: We retrospectively analyzed patients diagnosed with PSCCB in our center. All pathological slides were reviewed by an experienced pathologist to confirm the diagnosis. Furthermore, we searched the public database for patients with SCC of the breast. Then, we analyzed the clinicopathological features, treatment methods and patient outcomes. Results: We identified 14 patients with primary SCC of the breast in our center. Additionally, 739 patients with SCC of the breast from the Surveillance, Epidemiology and End Results (SEER) database were diagnosed between 1975 and 2016. Only 453 patients who underwent surgery were included in this study. Patients from the SEER database had a more advanced tumor node metastasis (TNM) stage than patients from our center. The median overall survival (OS) of all patients was 104 months (95% confidence interval [CI], 87.2–120.8 months), and the 5‐year OS was 60.8% (95% CI, 56.1%–65.5%). Most of the patients (58%) tested negative for hormonal receptor expression. Multivariate analysis showed that PORT was an independent prognostic factor for OS. Conclusion: The results of our study demonstrate that SCC of the breast presents aggressive behavior with unique clinical characteristics. PORT improved OS significantly in patients with SCC of the breast. Longer‐term studies are needed to confirm our findings. [ABSTRACT FROM AUTHOR]
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- 2021
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14. Simultaneously Tuning Charge Separation and Surface Reaction in a Fe2O3 Photoanode for Enhanced Photoelectrochemical Water Oxidation.
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Chen, Fukun, Zhang, Liwei, and Chen, Xingxing
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OXIDATION of water ,PHOTOELECTROCHEMISTRY ,SURFACE charges ,SURFACE reactions ,CHEMICAL energy ,SOLAR cells ,LAYERED double hydroxides - Abstract
Photoelectrochemical (PEC) water splitting has gained intensive attention owing to its capability of converting solar energy into chemical fuel, that is, hydrogen. However, the PEC efficiency is severely limited by the recombination of charge carriers and slow kinetics of surface water oxidation. The exploration of efficient photoanodes is, thus, urgently demanded. Herein, a bilateral charge modulation strategy for an improved Fe2O3 photoanode is reported. Z‐scheme Fe2O3‐g‐C3N4 heterojunction is first prepared with the aim of promoting the charge separation, followed by the electrodeposition of a NiFe‐based layered double hydroxide (LDH) on it in order to concurrently slow down the hole accumulation on the electrode surface and catalyze the water oxidation. The fabricated NiFe‐LDH@Fe2O3‐g‐C3N4 electrode exhibits an enhanced photocurrent density of 0.29 mA cm−2 at 1.23 VRHE, which is almost five times that of the pristine Fe2O3 (0.06 mA cm−2). This work provides an appealing maneuver for improving water oxidation performance in semiconductor‐based PEC systems. [ABSTRACT FROM AUTHOR]
- Published
- 2021
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15. Characteristics, prognosis, risk factors, and management of recently diagnosed ductal carcinoma in situ with microinvasion.
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Li, Chunyan, Yang, Yilan, Wang, Jiangfeng, Jin, Kairui, Yang, Zhaozhi, Yu, Xiaoli, Guo, Xiaomao, and Chen, Xingxing
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DUCTAL carcinoma ,PROGNOSIS ,DIAGNOSIS ,OVERALL survival ,SURVIVAL rate ,CARCINOMA in situ ,LUMPECTOMY - Abstract
Background: Ductal carcinoma in situ with microinvasion (DCISM) represents ~1% of all breast cancer cases and is arguably a more aggressive subtype of ductal carcinoma in situ (DCIS). Lacking studies with a large population, the survival outcomes of DCISM are still poorly understood and the treatment recommendations remain controversial. This study aims to investigate the long‐term outcome of patients with DCISM, potential risk factors for their prognosis, and the difference of survival between patients treated with breast‐conserving surgery plus radiotherapy (BCT + RT) and mastectomy only. Methods: In total, 1299 patients from 2008 to 2019 with DCISM were retrospectively retrieved. Clinicopathological features were analyzed. Subgroup analysis was conducted between patients who underwent BCT + RT and mastectomy only. Univariate and multivariate analyses were performed to identify prognostic factors for survival. Differences of survival between two groups were compared using the log‐rank test. Results: Totally, 1286 patients had follow‐up information, the median follow‐up is 54.57 months, the 5‐year local–regional‐free survival (LRFS), distant metastasis‐free survival (DMFS), and overall survival (OS) were 98.6%, 97.1%, and 99.4%, respectively, two deaths were due to breast cancer. Multivariate analysis identified age <40 (p = 0.028) and close margin (≤2 mm) as independent negative prognostic factors for LRFS. No prognostic factors were identified for DMFS and OS. The 5‐year LRFS, DMFS, and OS of patients who had DCIS component ≥5 cm and underwent mastectomy without adjuvant radiotherapy were 100%, 98.4%, and 98.4%, respectively. After propensity score matching (PSM), no survival difference was observed between patients treated with BCT + RT or mastectomy only. Conclusions: DCISM patients had a good survival, even those with DCIS component ≥5 cm. Patients aged <40 or with close margin (≤2 mm) had a poorer LRFS, but not DMFS or OS. BCT + RT is a feasible choice for DCISM patients. [ABSTRACT FROM AUTHOR]
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- 2021
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16. Mixed Conduction in an N‐Type Organic Semiconductor in the Absence of Hydrophilic Side‐Chains.
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Surgailis, Jokubas, Savva, Achilleas, Druet, Victor, Paulsen, Bryan D., Wu, Ruiheng, Hamidi‐Sakr, Amer, Ohayon, David, Nikiforidis, Georgios, Chen, Xingxing, McCulloch, Iain, Rivnay, Jonathan, and Inal, Sahika
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SCANNING force microscopy ,ATOMIC force microscopy ,ORGANIC conductors ,HYDROPHILIC interactions ,IONIC structure ,GRAZING incidence ,N-type semiconductors ,MEMRISTORS - Abstract
Organic electrochemical transistors (OECTs) are the building blocks of biosensors, neuromorphic devices, and complementary circuits. One rule in the materials design for OECTs is the inclusion of a hydrophilic component in the chemical structure to enable ion transport in the film. Here, it is shown that the ladder‐type, side‐chain free polymer poly(benzimidazobenzophenanthroline) (BBL) performs significantly better in OECTs than the donor–acceptor type copolymer bearing hydrophilic ethylene glycol side chains (P‐90). A combination of electrochemical techniques reveals that BBL exhibits a more efficient ion‐to‐electron coupling and higher OECT mobility than P‐90. In situ atomic force microscopy scans evidence that BBL, which swells negligibly in electrolytes, undergoes a drastic and permanent change in morphology upon electrochemical doping. In contrast, P‐90 substantially swells when immersed in electrolytes and shows moderate morphology changes induced by dopant ions. Ex situ grazing incidence wide‐angle X‐ray scattering suggests that the particular packing of BBL crystallites is minimally affected after doping, in contrast to P‐90. BBL's ability to show exceptional mixed transport is due to the crystallites' connectivity, which resists water uptake. This side chain‐free route for the design of mixed conductors could bring the n‐type OECT performance closer to the bar set by their p‐type counterparts. [ABSTRACT FROM AUTHOR]
- Published
- 2021
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17. n‐Type Rigid Semiconducting Polymers Bearing Oligo(Ethylene Glycol) Side Chains for High‐Performance Organic Electrochemical Transistors.
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Chen, Xingxing, Marks, Adam, Paulsen, Bryan D., Wu, Ruiheng, Rashid, Reem B., Chen, Hu, Alsufyani, Maryam, Rivnay, Jonathan, and McCulloch, Iain
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POLYMERS , *TRANSISTORS , *ELECTRON mobility , *CONJUGATED polymers , *ETHYLENE glycol , *ALDOL condensation , *BIOELECTRONICS - Abstract
N‐type conjugated polymers as the semiconducting component of organic electrochemical transistors (OECTs) are still undeveloped with respect to their p‐type counterparts. Herein, we report two rigid n‐type conjugated polymers bearing oligo(ethylene glycol) (OEG) side chains, PgNaN and PgNgN, which demonstrated an essentially torsion‐free π‐conjugated backbone. The planarity and electron‐deficient rigid structures enable the resulting polymers to achieve high electron mobility in an OECT device of up to the 10−3 cm2 V−1 s−1 range, with a deep‐lying LUMO energy level lower than −4.0 eV. Prominently, the polymers exhibited a high device performance with a maximum dimensionally normalized transconductance of 0.212 S cm−1 and the product of charge‐carrier mobility μ and volumetric capacitance C* of 0.662±0.113 F cm−1 V−1 s−1, which are among the highest in n‐type conjugated polymers reported to date. Moreover, the polymers are synthesized via a metal‐free aldol‐condensation polymerization, which is beneficial to their application in bioelectronics. [ABSTRACT FROM AUTHOR]
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- 2021
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18. Phosphorylation of myelin regulatory factor by PRKG2 mediates demyelination in Huntington's disease.
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Yin, Peng, Liu, Qiong, Pan, Yongcheng, Yang, Weili, Yang, Su, Wei, Wenjie, Chen, Xingxing, Hong, Yan, Bai, Dazhang, Li, Xiao‐Jiang, and Li, Shihua
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Demyelination is a common pathological feature of a large number of neurodegenerative diseases including multiple sclerosis and Huntington's disease (HD). Laquinimod (LAQ) has been found to have therapeutic effects on multiple sclerosis and HD. However, the mechanism underlying LAQ's therapeutic effects remains unknown. Using HD mice that selectively express mutant huntingtin in oligodendrocytes and show demyelination, we found that LAQ reduces the Ser259 phosphorylation on myelin regulatory factor (MYRF), an oligodendrocyte‐specific transcription factor promoting the expression of myelin‐associated genes. The reduced MYRF phosphorylation inhibits MYRF's binding to mutant huntingtin and increases the expression of myelin‐associated genes. We also found that PRKG2, a cGMP‐activated protein kinase subunit II, promotes the Ser259‐MYRF phosphorylation and that knocking down PRKG2 increased myelin‐associated protein's expression in HD mice. Our findings suggest that PRKG2‐regulated phosphorylation of MYRF is involved in demyelination and can serve as a potential therapeutic target for reducing demyelination. Synopsis: Laquinimod reduces Ser259 phosphorylation of myelin regulatory factor and its binding to mutant huntingtin, alleviating expression of myelin‐associated genes and demyelination caused by mutant huntingtin in oligodendrocytes. Laquinimod alleviates the phenotypes and pathology of HD mice expressing mutant HTT in oligodendrocytes.Laquinimod inhibits the interaction of mutant HTT with MYRF by reducing the phosphorylation of MYRF and restores the expression of myelin genes.Reducing the phosphorylation of MYRF by knocking down PRKG2 increases the expression of myelin genes in HD mice. [ABSTRACT FROM AUTHOR]
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- 2020
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19. Biological subtype predicts locoregional recurrence after postmastectomy radiotherapy in Chinese breast cancer patients.
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Wang, Jiangfeng, Luo, Jurui, Jin, Kairui, Wang, Xuanyi, Yang, Zhaozhi, Ma, Jinli, Mei, Xin, Wang, Xiaofang, Zhou, Zhirui, Yu, Xiaoli, Chen, Xingxing, and Guo, Xiaomao
- Subjects
BREAST cancer ,TRIPLE-negative breast cancer ,CANCER patients ,IMMUNOSTAINING ,RADIOTHERAPY - Abstract
Aim: To investigate the impact of biological subtypes in locoregional recurrence in Chinese breast cancer patients receiving postmastectomy radiotherapy (PMRT). Methods and Materials: About 583 patients who received postmastectomy radiation between 2010 and 2012 were retrospectively analyzed. According to immunohistochemical staining profile, patients were classified into: Luminal A‐like, Luminal B‐like, HER2‐positive, and triple‐negative breast cancer (TNBC). Local and regional recurrence (LRR) cumulative incidences were calculated by competing risks methodology and the power of prognostic factors was examined by Gray's test and the test of Fine and Gray. Results: The median follow‐up was 70.9 months. About 34 LRR events occurred. For Luminal A, Luminal B, HER2‐positive, and TNBC patients, the 5‐year LRR cumulative incidence rates were 1.57%, 4.09%, 10.74%, and 10.28%. Compared with Luminal A, HER2‐positive subtype and TNBC had a significant increased risk of LRR (HR was 5.034 and 5.188, respectively). In univariate analysis, predictive factors for higher LRR were HER2‐positive subtype (HR = 4.43, P <.05), TNBC (HR = 4.70, P <.05), and pN3 (HR = 5.83, P <.05). In the multivariate model, HER2‐positive subtype (HR = 5.034, P <.05), TNBC (HR = 5.188, P <.05), and pN3 (HR = 9.607, P <.01) were independent predictors of LRR. LRR without trastuzumab was similar to that of TNBC (without vs TNBC, 17.88% vs 10.28%, P >.05) in HER2‐positive subtype patients, while LRR with trastuzumab was approximate to Luminal A (with vs Luminal A, P >.05). Additionally, endocrine therapy also significantly reduced LRR incidence in the luminal subtype cohort (without vs with therapy, 6.25% vs 2.89%, HR = 0.365, P <.1). Conclusions: Biological subtype was a prognostic factor of LRR in the PMRT setting among Chinese breast cancer patients. [ABSTRACT FROM AUTHOR]
- Published
- 2020
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- View/download PDF
20. Engineering Versatile Nanoparticles for Near‐Infrared Light‐Tunable Drug Release and Photothermal Degradation of Amyloid β.
- Author
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Lai, Yi, Zhu, Yingying, Xu, Zhiai, Hu, Xianli, Saeed, Madiha, Yu, Haijun, Chen, Xingxing, Liu, Jun, and Zhang, Wen
- Subjects
NANOMEDICINE ,AMYLOID ,PHOTOTHERMAL effect ,ALZHEIMER'S disease ,TREATMENT effectiveness ,NANOPARTICLES ,CONJUGATED polymers - Abstract
Nanomedicines that inhibit/disassemble amyloid β (Aβ) aggregates in Alzheimer's disease (AD) are highly desirable yet remain challenging. Therapeutic efficacy and systemic delivery of reported molecules and nanoparticles (NPs) are hampered by various challenges, including low biocompatibility, off‐target toxicity, and lack of specificity. Herein, a versatile NP is designed by integrating high Aβ‐binding affinity, stimuli‐responsive drug release, and photothermal degradation properties for efficient disassembly of Aβ. Near‐infrared (NIR)‐absorbing conjugated polymer PDPP3T‐O14 serves as a photothermal core while thermal‐responsive polymer 1,2‐dipalmitoyl‐sn‐glycero‐3‐phosphocholine at the outer layer as the NIR‐stimuli gatekeeper. Curcumin, an inhibitor of Aβ aggregation, is loaded into the NP with high encapsulation efficiency. The 5‐mer β‐sheet breaker peptides LPFFD (Leu‐Pro‐Phe‐Phe‐Asp) having high binding affinity toward Aβ are further anchored onto the surface of polyethylene glycol‐lipid shell for active Aβ‐targeting. The resultant NPs exhibit good Aβ‐targeting ability and obvious photothermal dissociation effect together with Aβ aggregation‐dependent fluorescence detection capability. Upon NIR laser irradiation, entrapped curcumin can be effectively released from the unconsolidated NPs to enhance the anti‐amyloid activity. In vitro studies demonstrate that the NPs dramatically lower Aβ‐induced cytotoxicity of PC12 cells, and therefore show great potential for the application in AD treatment. [ABSTRACT FROM AUTHOR]
- Published
- 2020
- Full Text
- View/download PDF
21. Balancing Ionic and Electronic Conduction for High‐Performance Organic Electrochemical Transistors.
- Author
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Savva, Achilleas, Hallani, Rawad, Cendra, Camila, Surgailis, Jokubas, Hidalgo, Tania C., Wustoni, Shofarul, Sheelamanthula, Rajendar, Chen, Xingxing, Kirkus, Mindaugas, Giovannitti, Alexander, Salleo, Alberto, McCulloch, Iain, and Inal, Sahika
- Subjects
TRANSISTORS ,ENERGY harvesting ,ETHYLENE glycol ,CONJUGATED polymers ,POLYELECTROLYTES ,AQUEOUS electrolytes ,ELECTROCHEMICAL analysis - Abstract
Conjugated polymers that support mixed (electronic and ionic) conduction are in demand for applications spanning from bioelectronics to energy harvesting and storage. To design polymer mixed conductors for high‐performance electrochemical devices, relationships between the chemical structure, charge transport, and morphology must be established. A polymer series bearing the same p‐type conjugated backbone with increasing percentage of hydrophilic, ethylene glycol side chains is synthesized, and their performance in aqueous electrolyte gated organic electrochemical transistors (OECTs) is studied. By using device physics principles and electrochemical analyses, a direct relationship is found between the OECT performance and the balanced mixed conduction. While hydrophilic side chains are required to facilitate ion transport—thus enabling OECT operation—swelling of the polymer is not de facto beneficial for balancing mixed conduction. It is shown that heterogeneous water uptake disrupts the electronic conductivity of the film, leading to OECTs with lower transconductance and slower response times. The combination of in situ electrochemical and structural techniques shown here contributes to the establishment of the structure–property relations necessary to improve the performance of polymer mixed conductors and subsequently of OECTs. [ABSTRACT FROM AUTHOR]
- Published
- 2020
- Full Text
- View/download PDF
22. Carbon‐Nanoplated CoS@TiO2 Nanofibrous Membrane: An Interface‐Engineered Heterojunction for High‐Efficiency Electrocatalytic Nitrogen Reduction.
- Author
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Liu, Yi‐Tao, Chen, Xingxing, Yu, Jianyong, and Ding, Bin
- Subjects
- *
CHEMICAL kinetics , *HETEROJUNCTIONS , *INTERFACIAL reactions , *CHARGE transfer , *ELECTROCATALYSTS , *NITROGEN - Abstract
Developing noble‐metal‐free electrocatalysts is important to industrially viable ammonia synthesis through the nitrogen reduction reaction (NRR). However, the present transition‐metal electrocatalysts still suffer from low activity and Faradaic efficiency due to poor interfacial reaction kinetics. Herein, an interface‐engineered heterojunction, composed of CoS nanosheets anchored on a TiO2 nanofibrous membrane, is developed. The TiO2 nanofibrous membrane can uniformly confine the CoS nanosheets against agglomeration, and contribute substantially to the NRR performance. The intimate coupling between CoS and TiO2 enables easy charge transfer, resulting in fast reaction kinetics at the heterointerface. The conductivity and structural integrity of the heterojunction are further enhanced by carbon nanoplating. The resulting C@CoS@TiO2 electrocatalyst achieves a high ammonia yield (8.09×10−10 mol s−1 cm−2) and Faradaic efficiency (28.6 %), as well as long‐term durability. [ABSTRACT FROM AUTHOR]
- Published
- 2019
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- View/download PDF
23. Inhibition of prostaglandin E2 receptor 4 by lnc000908 to promote the endothelial‐mesenchymal transition participation in cardiac remodelling.
- Author
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Chen, Xingxing, Ge, Wenhua, Hu, Jie, Dong, Tiancheng, Yao, Hui, Chen, Lingzhi, Geng, Bin, and Zhou, Hao
- Subjects
PROSTAGLANDIN receptors ,DINOPROSTONE ,HEART fibrosis ,TRANSFORMING growth factors-beta ,HEART diseases ,NON-coding RNA - Abstract
Long non‐coding RNAs (lncRNAs) have emerged as potent regulators of cardiac disease; however, the role of lncRNA in cardiac fibrosis remains partially understood. In this study, we identified a cardiac endothelial‐enriched lncRNA‐lnc000908, which was markedly up‐regulated in rats with cardiac fibrosis. In addition, the expression of prostaglandin E2 receptor 4 (EP4) was decreased in cardiac fibrosis. In vivo lnc000908 silencing by lentivirus increased the EP4 level, decreased endothelial‐mesenchymal transition (EndMT) and improved cardiac fibrosis and cardiac function. Consistently, the lnc000908 knockdown also up‐regulated EP4 and suppressed transforming growth factor‐beta (TGF‐β)‐induced EndMT in cardiac microvascular endothelial cells. In contrast, the lnc000908 overexpression by lentivirus decreased the EP4 level and induced EndMT. Of note, these pro‐ or anti‐EndMT effects were reversed by the EP4 overexpression or the EP4 antagonist AH‐23848, respectively. This study demonstrates that lnc000908 is a novel regulator of cardiac fibrosis by modulating the EP4 expression and EndMT. [ABSTRACT FROM AUTHOR]
- Published
- 2019
- Full Text
- View/download PDF
24. In vivo study of rat cortical hemodynamics using a stereotaxic‐apparatus‐compatible photoacoustic microscope.
- Author
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Guo, Heng, Chen, Qian, Qi, Weizhi, Chen, Xingxing, and Xi, Lei
- Abstract
Brain imaging is an important technique in cognitive neuroscience. In this article, we designed a stereotaxic‐apparatus‐compatible photoacoustic microscope for the studies of rat cortical hemodynamics. Compared with existing optical resolution photoacoustic microscopy (ORPAM) systems, the probe owns feature of fast, light and miniature. In this microscope, we integrated a miniaturized ultrasound transducer with a center frequency of 10 MHz to detect photoacoustic signals and a 2‐dimensional (2D) microelectromechanical system (MEMS) scanner to achieve raster scanning of the optical focus. Based on phantom evaluation, this imaging probe has a high lateral resolution of 3.8 μm and an effective imaging domain of 2 × 2 mm
2 . Different from conventional ORPAMs, combining with standard stereotaxic apparatus enables broad studies of rodent brains without any motion artifact. To show its capability, we successfully captured red blood cell flow in the capillary, monitored the vascular changes during bleeding and blood infusion and visualized cortical hemodynamics induced by middle cerebral artery occlusion. [ABSTRACT FROM AUTHOR]- Published
- 2018
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- View/download PDF
25. Local recurrence is correlated with decreased overall survival in patients with intermediate high‐grade localized primary soft tissue sarcoma of extremity and abdominothoracic wall.
- Author
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Zhao, Ruping, Yu, Xiaoli, Feng, Yan, Yang, Zhaozhi, Chen, Xingxing, Wand, Jian, Ma, Shenglin, Zhang, Zhen, and Guo, Xiaomao
- Subjects
SARCOMA ,CANCER treatment ,RADIOTHERAPY ,SURVIVAL analysis (Biometry) ,MULTIPLE regression analysis ,ABDOMINAL wall ,PATIENTS - Abstract
Abstract: Aim: The aim of this study was to determine the effect of local recurrence on overall survival in patients with intermediate high‐grade localized primary soft tissue sarcoma (STS) of extremity and abdominothoracic wall. Methods: This retrospective study identified 133 consecutive patients with intermediate high‐grade localized primary STS of extremity and abdominothoracic wall from January 2000 to July 2010. Survival curves were constructed by the Kaplan–Meier method and log‐rank test was used to assess statistical significance. Hazard ratios (HRs) were calculated based on multivariable Cox logistic regression method. Results: The 5‐year cumulative incidence of local recurrence was 26.0% with a median follow‐up of 68 months (range, 5–127 months). The univariate analysis showed that local recurrence was associated with decreased overall survival, with 5‐year overall survival of 80.5% and 53.6% in the no local recurrence patients and local recurrence patients, respectively (
P = 0.001). The multivariate analysis demonstrated that local recurrence was a negative prognostic factor for overall survival (HR = 2.115, 95% confidence interval [CI] 1.036–4.319,P = 0.040). Radiotherapy significantly reduced local recurrence compared with surgery alone (HR = 0.387, 95% CI 0.180–0.877,P = 0.019), while larger tumor size (HR = 3.184, 95% CI 1.351–7.506P = 0.008) was correlated with higher rate of local recurrence. Conclusion: Local recurrence in patients with intermediate high‐grade localized primary STS is associated with decreased overall survival. [ABSTRACT FROM AUTHOR]- Published
- 2018
- Full Text
- View/download PDF
26. Controlling fluorescence emission with split-ring-resonator-based plasmonic metasurfaces.
- Author
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Luo, Si, Li, Qiang, Yang, Yuanqing, Chen, Xingxing, Wang, Wei, Qu, Yurui, and Qiu, Min
- Subjects
METAMATERIALS ,ELECTROMAGNETIC waves ,FLUORESCENCE ,ELECTRIC fields ,OPTICAL polarization - Abstract
Metasurfaces, which consist of resonant metamaterial elements in the form of two-dimensional thin planar structures, retain great capabilities in manipulating electromagnetic wave and potential applications in modifying interaction with fluorescent molecules. The metasurfaces with magnetic responses are favorable to weakening fluorescence quenching while less investigated in controlling fluorescence. In this paper, we demonstrate control over fluorescence emission by engineering the magnetic and electric modes in plasmonic metasurfaces consisting of 45-nm-thick gold split-ring-resonators (SRRs). The fluorescence emission exhibits an enhancement factor of ∼18 and is predominantly x-polarized with assistance of the magnetic mode excited by oblique incidence with an x-polarized electric field. The magnetic and electric modes excited by oblique incidence with a y-polarized electric field contribute to the rotation of emission polarization with respect to the incident polarization. The results demonstrate manipulating the interaction of fluorescent emitters with different resonant modes of the SRR-based metasurface at the nanoscale by the polarization of incident light, providing potential applications of metasurfaces in a wide variety of areas, including optical nanosources, fluorescence spectroscopy and compact biosensors. [ABSTRACT FROM AUTHOR]
- Published
- 2017
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- View/download PDF
27. One-pot Synthesized Co/Co3O4-N-Graphene Composite as Electrocatalyst for Oxygen Reduction Reaction and Oxygen Evolution Reaction.
- Author
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He, Bincai, Chen, Xingxing, Lu, Jingming, Yao, Songdong, Wei, Jiong, Zhao, Qi, Jing, Deshui, Huang, Xinning, and Wang, Tao
- Subjects
- *
CATALYSTS , *OXYGEN electrodes , *ELECTROCATALYSIS , *OXYGEN reduction , *RENEWABLE energy sources - Abstract
Efficient bifunctional catalysts for reversible oxygen electrodes, for electrocatalysis of both the oxygen reduction reaction (ORR) and the oxygen evolution reactions (OER) are envisioned to make a significant contribution towards the need for environmentally friendly and renewable energy systems. Despite tremendous efforts, there is still need for further development of bifunctional catalysts to achieve low-cost catalysts with stable satisfactory long-term performance, enhanced kinetics of the ORR and OER and high round-trip electrolytic-galvanic mode voltage efficiency. Herein, we demonstrate a simple one-pot procedure for synthesis of a bifunctional catalyst comprised of a composite of cobalt/cobalt oxide and N-doped graphene (denoted as Co/Co3O4-N-graphene), which exhibits very good performance in the electrocatalysis of both ORR and OER in alkaline solution. The prepared composite was characterized by TEM, SEM, Raman, XRD and XPS, to give insight of its structure-performance correlation. The results reveal that the structure of N-doped graphene is preserved and that both metallic Co and its oxide form of Co3O4 co-existed in the prepared composite, with metallic Co being predominant crystalline component. Generally, a high ratio of Co in the prepared composite led to improvement of the onset potential for the OER. [ABSTRACT FROM AUTHOR]
- Published
- 2016
- Full Text
- View/download PDF
28. Influenceof Vinyl Acetate Content on the Surface Hydrophobic Recovery of Ethylene Vinyl Acetate Copolymer after Plasma Modification.
- Author
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Chen, Xingxing, Huang, Long, Dong, Changji, Niu, Lihui, Zhang, Yong, and Chen, Zhe
- Subjects
- *
VINYL acetate , *HYDROPHOBIC compounds , *COPOLYMERS - Abstract
In this paper, two kinds of ethylene vinyl acetate copolymers (EVA) with different vinyl acetate (VA) contents were modified by plasma technique. The surface hydrophobic recovery and the nanostructure of the samples were evaluated by water contact angle measurement and positron annihilation lifetime spectroscopy, respectively. The water contact angle results indicated that higher VA content would result in faster hydrophobic recovery after plasma modification. The positron annihilation results indicated that two kinds of EVA samples exhibited similar o‐Ps lifetime, and EVA with higher VA content showed higher o‐Ps intensity. The results implied that the faster hydrophobic recovery after plasma modification should be contributed to the easier relaxation of chain segments for the EVA with higher VA content. Plasma modification is a powerful tool for surface modification, but the hydrophobic recovery limits the application of this technique. Ethylene vinyl acetate copolymers with different vinyl acetate (VA) contents were modified by plasma, and the hydrophobic recovery was evaluated by water contact angle measurement. It was found that higher VA content can lead to more free volume concentration, resulting in easier chain segment relaxation, which is in the charge of faster hydrophobic recovery. [ABSTRACT FROM AUTHOR]
- Published
- 2019
- Full Text
- View/download PDF
29. Diketopyrrolopyrrole-based Conjugated Polymers Bearing Branched Oligo(Ethylene Glycol) Side Chains for Photovoltaic Devices.
- Author
-
Chen, Xingxing, Zhang, Zijian, Ding, Zicheng, Liu, Jun, and Wang, Lixiang
- Subjects
- *
CONJUGATED polymers , *OPTOELECTRONIC devices , *ENERGY conversion , *BAND gaps , *PERMITTIVITY - Abstract
Conjugated polymers are essential for solution-processable organic opto-electronic devices. In contrast to the great efforts on developing new conjugated polymer backbones, research on developing side chains is rare. Herein, we report branched oligo(ethylene glycol) (OEG) as side chains of conjugated polymers. Compared with typical alkyl side chains, branched OEG side chains endowed the resulting conjugated polymers with a smaller π-π stacking distance, higher hole mobility, smaller optical band gap, higher dielectric constant, and larger surface energy. Moreover, the conjugated polymers with branched OEG side chains exhibited outstanding photovoltaic performance in polymer solar cells. A power conversion efficiency of 5.37 % with near-infrared photoresponse was demonstrated and the device performance could be insensitive to the active layer thickness. [ABSTRACT FROM AUTHOR]
- Published
- 2016
- Full Text
- View/download PDF
30. Control of fluorescence enhancement and directionality upon excitations in a thin-film system.
- Author
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Chen, Xingxing, Chen, Yu‐Hui, Qiu, Min, Blaikie, Richard J., and Ding, Boyang
- Subjects
- *
FLUORESCENCE , *THIN films , *FABRY-Perot interferometers , *DYES & dyeing , *MOLECULAR absorption spectra - Abstract
Nanostructures with various configurations have been extensively used to engineer the emission properties of embedded fluorophores, but lack the flexibility to dynamically control fluorescence. Here we report a thin-film cavity system, comprising a quarter wavelength thick dye-doped dielectric coating on a reflecting surface, in which the fluorescence enhancement and directionality can be significantly modified by altering the illumination angle. The configuration of the cavity yields absorption properties that are highly dependent on illumination angles, due to the coupling between molecular absorption and Fabry-Perot resonances. Therefore the fluorescence intensity relating to the angle-dependent absorbing efficiency varies with illumination angles. In addition, as a result of synergy between intrinsic absorption of the reflecting surface, Fabry-Perot and surface-plasmon-polariton resonances and illumination-angle dependent excitation efficiencies for differently located molecules, the global emission intensity, including emission from dyes at all locations, can be directionally redistributed by altering the illumination angle. [ABSTRACT FROM AUTHOR]
- Published
- 2015
- Full Text
- View/download PDF
31. Using Cavity Microelectrodes for Electrochemical Noise Studies of Oxygen-Evolving Catalysts.
- Author
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Rincón, Rosalba A., Battistel, Alberto, VENtosa, Edgar, ChEN, Xingxing, Nebel, Michaela, and Schuhmann, Wolfgang
- Subjects
MICROELECTRODES ,ELECTRODES ,ULTRAMICROELECTRODES ,CATALYSTS ,CATALYSIS - Abstract
Cavity microelectrodes were used as a binder-free platform to evaluate oxygen evolution reaction (OER) electrocatalysts with respect to gas bubble formation and departure. Electrochemical noise measurements were performed by using RuO
2 as a benchmark catalyst and the perovskite La0.58 Sr0.4 Fe0.8 Co0.2 O3 as a non-noble metal OER catalyst with lower intrinsic conductivity. Changes in the current during the OER originate from variations in electrolyte resistance during the formation of the gas phase and partial coverage of the active area. Fluctuations observed in current and conductance transients were used to establish the contribution from the ohmic overpotential and to determine the characteristic frequency of oxygen evolution. The proposed quantitative determination of gas bubble growth and departure opens up the route for a rational interface design by considering gas bubble growth and departure as a main contributing factor to the overall electrocatalytic activity at high current densities. [ABSTRACT FROM AUTHOR]- Published
- 2015
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- View/download PDF
32. Optimization of Os-Complex Modified Redox Polymers for Improving Biocatalysis of PQQ-sGDH Based Electrodes.
- Author
-
Pinyou, Piyanut, Pöller, Sascha, Chen, Xingxing, and Schuhmann, Wolfgang
- Subjects
POLYMERS ,REDOX polymers ,OXIDATION-reduction reaction ,ELECTRODES ,ELECTROCHEMISTRY ,ELECTROCHEMICAL analysis - Abstract
A variety of Os-complex modified redox polymers were synthesized and optimized for an improved bioelectrochemical communication with PQQ-sGDH. The properties of the polymers were varied by changing the monomers composition leading to improved immobilization and increased enzyme loading. Three Os-complexes were designed exhibiting different ligands but similar redox potentials adapted for efficient electron transfer with PQQ-sGDH. Effects of the ligand sphere, polymer backbone and length of the tether chain between Os-complex and polymer backbone as well as the impact of different bifunctional crosslinkers on the catalytic current were evaluated. The optimized bioelectrodes exhibited significantly improved catalytic currents and stability. [ABSTRACT FROM AUTHOR]
- Published
- 2015
- Full Text
- View/download PDF
33. Analysis in early stage triple-negative breast cancer treated with mastectomy without adjuvant radiotherapy: Patterns of failure and prognostic factors.
- Author
-
Chen, Xingxing, Yu, Xiaoli, Chen, Jiayi, Zhang, Zhen, Tuan, Jeffrey, Shao, Zhimin, Guo, Xiaomao, and Feng, Yan
- Subjects
- *
BREAST cancer treatment , *MASTECTOMY , *ADJUVANT treatment of cancer , *CANCER relapse , *MULTIVARIATE analysis , *KAPLAN-Meier estimator , *PROPORTIONAL hazards models - Abstract
BACKGROUND The objective of this study was to evaluate and identify patterns of failure and prognostic factors for locoregional recurrence (LRR) that could justify postmastectomy radiotherapy after modified radical mastectomy in patients with early stage triple-negative breast cancer. METHODS Between January 2000 and July 2007, the authors retrospectively analyzed 390 patients who had triple-negative breast cancer with T1/T2 tumors and from zero to 3 positive lymph nodes (pathologic T1-T2N0-N1) who underwent modified radical mastectomy without postmastectomy radiotherapy at the author's institution. The 5-year cumulative incidence for events was calculated using Kaplan-Meier analysis, and subgroups were compared using the log-rank test. Multivariate analysis was performed using a Cox proportional hazards model. RESULTS Overall, 86.4% of patients received chemotherapy. At a median follow-up of 60.5 months, the 5-year cumulative rates of local recurrence, regional recurrence, LRR, and distant metastasis were 5.4%, 4.7%, 8%, and 13.4%, respectively. On multivariate analysis, age <50 years, the presence of lymphovascular invasion, grade 3 tumor, and 3 involved lymph nodes were associated significantly with an increased risk of LRR. The 5-year LRR rate for patients who had 0 or 1 risk factor, 2 risk factors, and 3 or 4 risk factors was 4.2%, 25.2%, and 81% ( P < .0001), respectively. The presence of lymphovascular invasion and having 3 involved lymph nodes were statistically significant predictors of regional recurrence, and the patients who had regional recurrence had a significantly greater risk of distant metastases compared with patients who had local recurrence (59.1% vs 20.9%; P < .0001). CONCLUSIONS Several risk factors were identified in this study that correlated independently with a greater incidence of LRR in patients who had early stage triple-negative breast cancer. The current results indicated that postmastectomy radiotherapy should be considered for those patients who have 2 or more of these factors. Cancer 2013;119:2366-2374. © 2013 American Cancer Society. [ABSTRACT FROM AUTHOR]
- Published
- 2013
- Full Text
- View/download PDF
34. Evaluation of the bactericidal effect of Nd:YAG, Er:YAG, Er,Cr:YSGG laser radiation, and antimicrobial photodynamic therapy (aPDT) in experimentally infected root canals.
- Author
-
Cheng, Xiaogang, Guan, Sumin, Lu, Hong, Zhao, Chunmiao, Chen, Xingxing, Li, Na, Bai, Qian, Tian, Yu, and Yu, Qing
- Published
- 2012
- Full Text
- View/download PDF
35. Electrochemical Synthesis of Core-Shell Catalysts for Electrocatalytic Applications.
- Author
-
Kulp, Christian, Chen, Xingxing, Puschhof, Andrea, Schwamborn, Stefanie, Somsen, Christoph, Schuhmann, Wolfgang, and Bron, Michael
- Published
- 2010
- Full Text
- View/download PDF
36. Patterned CNT Arrays for the Evaluation of Oxygen Reduction Activity by SECM.
- Author
-
Schwamborn, Stefanie, Stoica, Leonard, Chen, Xingxing, Xia, Wei, Kundu, Shankhamala, Muhler, Martin, and Schuhmann, Wolfgang
- Published
- 2010
- Full Text
- View/download PDF
37. Visualization of the Local Catalytic Activity of Electrodeposited Pt-Ag Catalysts for Oxygen Reduction by means of SECM.
- Author
-
Nagaiah, Tharamani C., Maljusch, Artjom, Chen, Xingxing, Bron, Michael, and Schuhmann, Wolfgang
- Published
- 2009
- Full Text
- View/download PDF
38. On the Role of Contact Resistance and Electrode Modification in Organic Electrochemical Transistors.
- Author
-
Paterson, Alexandra F., Faber, Hendrik, Savva, Achilleas, Nikiforidis, Georgios, Gedda, Murali, Hidalgo, Tania C., Chen, Xingxing, McCulloch, Iain, Anthopoulos, Thomas D., and Inal, Sahika
- Published
- 2019
- Full Text
- View/download PDF
39. Catalyst‐Free One‐Step Preparation of Self‐Crosslinked pH‐Responsive Vesicles.
- Author
-
Tan, Jidong, Lei, Hengxin, Liaw, Der‐Jang, Chen, Xingxing, Ma, Li, Cui, Chenhui, Zhong, Qianyun, Cheng, Yilong, and Zhang, Yanfeng
- Subjects
POLYMERSOMES ,DIFFUSION ,SMALL molecules ,ETHYLENE glycol ,ORGANIC solvents ,MEMBRANE permeability (Biology) - Abstract
The fabrication of block copolymer (BCP) vesicles with controlled membrane permeability and promising stability remains a considerable challenge. Herein, a new type of pH‐responsive and self‐crosslinked vesicle based on a hydrolytically hindered urea bond is reported. This kind of vesicle is formed by the self‐assembly of a pH‐responsive and hydrolytically self‐crosslinkable copolymer poly(ethylene glycol)‐block‐poly[2‐(3‐(tert‐butyl)‐3‐ethylureido)ethyl methacrylate‐co‐2‐(diethylamino)ethyl methacrylate] (PEG‐b‐P(TBEU‐co‐DEA)). The BCP can be easily synthesized by reversible addition–fragmentation chain transfer (RAFT) polymerization of 2‐(3‐(tert‐butyl)‐3‐ethylureido)ethyl methacrylate (TBEU) and 2‐(diethylamino)ethyl methacrylate (DEA) using PEG‐based macro‐chain transfer agent. The copolymer could self‐assemble into stable vesicles by the hydrophobic interaction and in situ cross‐linking between amines and isocyanates after the hydrolysis of the hindered urea bonds without any catalyst. Dynamic light scattering (DLS) studies show that the vesicles exhibit enhanced stability against the dilution of organic solvent, and the size can be adjusted through the change of pH values. Moreover, the alkaline phosphatase‐loaded vesicles can act as nano‐reactor and enable free diffusion of small molecules into the vesicles, followed by the significantly improved fluorescence intensity of phosphate‐caged fluorescein. This self‐crosslinking and pH‐sensitive vesicles may serve as a smart platform in controlled drug delivery and molecular reactor. [ABSTRACT FROM AUTHOR]
- Published
- 2019
- Full Text
- View/download PDF
40. Solvent Engineering for High‐Performance n‐Type Organic Electrochemical Transistors.
- Author
-
Savva, Achilleas, Ohayon, David, Surgailis, Jokubas, Paterson, Alexandra F., Hidalgo, Tania C., Chen, Xingxing, Maria, Iuliana P., Paulsen, Bryan D., Petty, Anthony J., Rivnay, Jonathan, McCulloch, Iain, and Inal, Sahika
- Subjects
ORGANIC field-effect transistors ,ENGINEERING ,TRANSISTORS ,POLYMER solutions ,ACETONE - Abstract
Organic electrochemical transistors (OECTs) exhibit strong potential for various applications in bioelectronics, especially as miniaturized, point‐of‐care biosensors, because of their efficient transducing ability. To date, however, the majority of reported OECTs have relied on p‐type (hole transporting) polymer mixed conductors, due to the limited number of n‐type (electron transporting) materials suitable for operation in aqueous electrolytes, and the low performance of those which exist. It is shown that a simple solvent‐engineering approach boosts the performance of OECTs comprising an n‐type, naphthalenediimide‐based copolymer in the channel. The addition of acetone, a rather bad solvent for the copolymer, in the chloroform‐based polymer solution leads to a three‐fold increase in OECT transconductance, as a result of the simultaneous increase in volumetric capacitance and electron mobility in the channel. The enhanced electrochemical activity of the polymer film allows high‐performance glucose sensors with a detection limit of 10 × 10−6m of glucose and a dynamic range of more than eight orders of magnitude. The approach proposed introduces a new tool for concurrently improving the conduction of ionic and electronic charge carriers in polymer mixed conductors, which can be utilized for a number of bioelectronic applications relying on efficient OECT operation. [ABSTRACT FROM AUTHOR]
- Published
- 2019
- Full Text
- View/download PDF
41. Assessing hemorrhagic shock: Feasibility of using an ultracompact photoacoustic microscope.
- Author
-
Chen, Qian, Guo, Heng, Qi, Weizhi, Gan, Qi, Yang, Lei, Ke, Bowen, Chen, Xingxing, Jin, Tian, and Xi, Lei
- Abstract
Hemorrhagic shock, as an important clinical issue, is regarding as a critical disease with a high mortality rate. Unfortunately, existing clinical technologies are inaccessible to assess the hemorrhagic shock via hemodynamics in microcirculation. Here, we propose an ultracompact photoacoustic microscope to assess hemorrhagic shock using a rat model and demonstrate its clinical feasibility by visualizing buccal microcirculation of healthy volunteers. Both functional and morphological features of the microvascular network including concentration of total hemoglobin (CHbT), number of blood vessels (VN), small vascular density (SVD) and vascular diameter (VD) were derived to assess the microvascular hemodynamics of different organs. Animal studies show the feasibility of the proposed tool to assess and stage the hemorrhagic shock via microcirculation. in vivo oral imaging of healthy volunteers indicates the translational possibility of this technique for clinical evaluation of hemorrhagic shock. Hemorrhagic shock is a critical disease with a high mortality rate. We developed an ultracompact photoacoustic microscope to investigate the hemodynamics during the entire course of hemorrhagic shock. We evaluate the microvasculature in brain and three internal organs during hypotension and blood perfusion stages of hemorrhagic shock. The figure shows the design of imaging probe and the photoacoustic imaging of brain, intestine, ovary and bladder, respectively. [ABSTRACT FROM AUTHOR]
- Published
- 2019
- Full Text
- View/download PDF
42. Titelbild: Diketopyrrolopyrrole-based Conjugated Polymers Bearing Branched Oligo(Ethylene Glycol) Side Chains for Photovoltaic Devices (Angew. Chem. 35/2016).
- Author
-
Chen, Xingxing, Zhang, Zijian, Ding, Zicheng, Liu, Jun, and Wang, Lixiang
- Abstract
Ein großer Vorteil konjugierter Polymere ist ihre preiswerte Verarbeitung in Lösung. Um ihre Löslichkeit in organischen Lösungsmitteln zu erhöhen, werden diese Polymere üblicherweise mit flexiblen Alkylseitenketten ausgestattet. Wie J. Liu, L. Wang et al. in der Zuschrift auf S. 10532 ff. zeigen, erfüllt verzweigtes Oligoethylenglycol denselben Zweck. Durch den Einsatz von Lösungsverfahren können die Polymere in hoch effizienten Polymersolarzellen mit Nah‐IR‐Aktivität genutzt werden. [ABSTRACT FROM AUTHOR]
- Published
- 2016
- Full Text
- View/download PDF
43. Cover Picture: Diketopyrrolopyrrole-based Conjugated Polymers Bearing Branched Oligo(Ethylene Glycol) Side Chains for Photovoltaic Devices (Angew. Chem. Int. Ed. 35/2016).
- Author
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Chen, Xingxing, Zhang, Zijian, Ding, Zicheng, Liu, Jun, and Wang, Lixiang
- Subjects
- *
CONJUGATED polymers synthesis , *SUBSTITUENTS (Chemistry) - Abstract
The article cites reference of an article related to the synthesis of branched oligo side chains bearing diketopyrrolopyrrole-based conjugated polymers for photovoltaic devices by J. Liu and L. Wang et al which appeared in 2016 issue of journal.
- Published
- 2016
- Full Text
- View/download PDF
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