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163. Cardiac Sympathetic Nerve Sprouting and Susceptibility to Ventricular Arrhythmias after Myocardial Infarction

Author

Li, Chang-Yi and Li, Yi-Gang

Subjects
Article Subject, cardiovascular system, cardiovascular diseases
Abstract

Ventricular arrhythmogenesis is thought to be a common cause of sudden cardiac death following myocardial infarction (MI). Nerve remodeling as a result of MI is known to be an important genesis of life-threatening arrhythmias. It is hypothesized that neural modulation might serve as a therapeutic option of malignant arrhythmias. In fact, left stellectomy or β-blocker therapy is shown to be effective in the prevention of ventricular tachyarrhythmias (VT), ventricular fibrillation (VF), and sudden cardiac death (SCD) after MI both in patients and in animal models. Results from decades of research already evidenced a positive relationship between abnormal nerve density and ventricular arrhythmias after MI. In this review, we summarized the molecular mechanisms involved in cardiac sympathetic rejuvenation and mechanisms related to sympathetic hyperinnervation and arrhythmogenesis after MI and analyzed the potential therapeutic implications of nerve sprouting modification for ventricular arrhythmias and SCD control.

Published
2015
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164. Determinants of postoperative left atrial structural reverse remodeling in patients undergoing combined catheter ablation of atrial fibrillation and left atrial appendage closure procedure.

Author

Li, Yi‐Gang, Gong, Chang‐Qi, Zhao, Ming‐Zhe, Sun, Jian, Wang, Qun‐Shan, Zhang, Peng‐Pai, Feng, Xiang‐Fei, Yu, Yi, Yu, Yi‐Chi, and Liang, Bing‐Er

Subjects
*ATRIAL fibrillation, *CATHETER ablation, *COMPUTED tomography, *CONFIDENCE intervals, *LEFT heart ventricle, *HEART physiology, *LONGITUDINAL method, *POSTOPERATIVE period, *RISK assessment, *DISEASE relapse, *TREATMENT effectiveness, *PREOPERATIVE period, *LEFT heart atrium, *ODDS ratio, *VASCULAR remodeling, *VENTRICULAR ejection fraction
Abstract

Introduction: Catheter ablation of atrial fibrillation (AFCA) and left atrial appendage closure (LAAC) exert opposite effects on left atrial (LA) size. We aim to observe the net impact of combined AFCA and LAAC strategy on LA size and explore those factors which might affect the postprocedure LA structural remodeling. Methods: A total of 53 patients, who underwent combined AFCA and Watchman LAAC in our center from March to December 2017, were enrolled. Atrial fibrillation (AF) recurrence was monitored after the procedure. Left atrial volume (LAV) and left atrial appendage volume (LAAV) were measured by Mimics based on dual‐source computed tomography images. Results: At 6 months, sinus rhythm (SR) was maintained in 79.2% patients. LAV was significantly reduced (130.2 ± 36.3 mL to 107.1 ± 30.0 ml; P < .001) in SR maintenance group, but not in AF recurrence group (138.8 ± 39.3 mL to 137.9 ± 36.9 mL; P = .671). In SR group, preoperative LAAV/LAV ratio (B = −0.894; P = .015), NT‐proBNP (B = 0.005; P = .019) and left ventricular ejection fraction (LVEF) (B = −0.778; P < .001) could interactively affect the extent of postoperative LA structural reverse remodeling, among which LAAV/LAV ratio could independently predict the significance of reverse remodeling (≥15% reduction in LAV) (OR, 0.56; 95% CI, 0.34‐0.90; P = .018). A preoperative LAAV/LAV ratio less than 7.1% is indicative of significant LA structural reverse remodeling in this patient cohort. Conclusions: LA structural reverse remodeling could be evidenced in patients with maintained SR following combined AFCA and LAAC. Smaller LAAV/LAV ratio, higher NT‐proBNP or lower LVEF at baseline are associated with more significant LA structural reverse remodeling, while LAAV/LAV ratio can predict the significance of the process after one‐stop treatment. [ABSTRACT FROM AUTHOR]

Published
2019
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165. Cardiac arrhythmias : update on mechanisms and clinical managements

Author

Li, Yi-Gang, Benditt, David G., Klingenheben, Thomas, Hu, Kai, Feng, Dali, Li, Yi-Gang, Benditt, David G., Klingenheben, Thomas, Hu, Kai, and Feng, Dali

Abstract

Atrial fibrillation (AF) is one of the most common arrhythmias in adults and is associated with a high incidence of stroke and heart failure (HF). Despite the advance of AF catheter ablation during the past decades, the high reoccurrence rate of AF after catheter ablation urges improvements of diagnostic approaches, therapies, and technologies. P. D. Dallaglio et al. reviewed the role of adenosine in pulmonary vein isolation in a meta-analysis of 11 studies. The analysis revealed that adenosine is useful to unmask dormant connection (DC) after a first ablation procedure and further ablation at sites of DC would reduce the rate of redo procedures for postablation AF recurrence. The authors also suggested that the use of adenosine should be accompanied by sufficient waiting time. ...

Published
2016

166. Propagation properties of vortex beams in a ring photonic crystal fiber

Author

Wei Wei, Zhang Ling-Xiang, Zhang Zhi-Ming, Liao Wen-Ying, Fan Wan-De, Yang Zhen-Guo, and Li Yi-Gang

Subjects
Materials science, business.industry, Physics::Optics, General Physics and Astronomy, 02 engineering and technology, Ring (chemistry), 01 natural sciences, 010309 optics, 020210 optoelectronics & photonics, Optics, 0103 physical sciences, Vortex beam, 0202 electrical engineering, electronic engineering, information engineering, business, Photonic-crystal fiber
Abstract

In the last decade, the vortex beams have received lots of attention for their orbital angular momentum.When they are applied to optical fiber communication field,the data channels will increase and information propagation speed will be effectively improved. Recently, researchers have shown the capabilities of long length stably propagation, nonlinear frequency conversion and mode division multiplexing of vortex modes in a ring fiber. Due to the photonic crystal fiber(PCF) having very flexible design degrees of freedom, it will enable a wide range of propagation properties. In this paper, a SiO2 air-hole ring PCF is proposed for separation and propagation of optical vortex modes.By using COMSOL Multiphysics software,the vortex modes(TE01, HE21± and TM01) are simulated and calculated. The differences in effective refractive index between them are 4.59×10-4 and 3.62×10-4 respectively. One can analyze the propagation properties of vortex beams in the ring PCF by changing the size of first layer air hole radius and air hole pitch. When the incident light wavelength of TE01 mode ranges from 1650 nm to 1950 nm, this ring PCF can achieve a total dispersion variation between 44.18 to 45.83 ps·nm-1·km-1, which is tend to be flat. When incident light wavelength is 1550 nm, the nonlinear coefficient of TE01 mode vortex light is 1.37 W-1·km-1. Due to the fact that long wavelength light is easier to leakage through the cladding than the short wavelength light, the confinement loss increases with the wavelength. When incident light wavelength is 2000 nm, there is still an eight-orders-of-magnitude of the low confinement loss. Theoretically, flat dispersion and low loss vortex beams in this fiber can be beneficial to propagating stably, and the vortex modes lay the foundation for long distance propagation in the optical fiber. In the future, this ring PCF will be used in optical fiber communication field and applications in aspects such as continuous spectrum research, which can make it have immense advantage over traditional fibers.

Published
2017

177. TBX5mutations contribute to early-onset atrial fibrillation in Chinese and Caucasians

Author

Ma, Ji-Fang, primary, Yang, Fan, additional, Mahida, Saagar N., additional, Zhao, Ling, additional, Chen, Xiaomin, additional, Zhang, Michael L., additional, Sun, Zhijun, additional, Yao, Yan, additional, Zhang, Yi-Xin, additional, Zheng, Gu-Yan, additional, Dong, Jie, additional, Feng, Ming-Jun, additional, Zhang, Rui, additional, Sun, Jian, additional, Li, Shuo, additional, Wang, Qun-Shan, additional, Cao, Huiqing, additional, Benjamin, Emelia J., additional, Ellinor, Patrick T., additional, Li, Yi-Gang, additional, and Tian, Xiao-Li, additional

Published
2016
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182. High Power One- and Two-Order Cascaded Raman Lasers Based on Home-Made Phosphosilicate Fibre

Author

Feng Ming, Zhang Xiao-Guang, Wang Hongjie, Li Jing, Li Yi-Gang, LU Ke-Cheng, and LI Jia-Fang

Subjects
Materials science, business.industry, Slope efficiency, General Physics and Astronomy, Laser, Power (physics), law.invention, symbols.namesake, Optics, law, Order (business), symbols, Raman spectroscopy, business
Abstract

One- and two-order cascaded Raman fibre lasers are demonstrated by using home-made P-doped Raman fibres. An output power of 2.8 W at 1245 nm with a slope efficiency of 33.4% and an output power of 2.0 W at 1495 nm with a slope efficiency of 23.5% are obtained with the pump source at 1069.7 nm.

Published
2005

183. High-Power Er 3+ /Yb 3+ Codoped Double-Cladding Fibre Amplifier with More Than 2 W Output Power

Author

Liu Yan-Ge, Yuan Shu-Zhong, Li Li-Jun, Kai Gui-Yun, LI Yi-Gang, Dong Xiao-Yi, Feng Xin-Huan, and Li Yao

Subjects
Wavelength, Optics, Materials science, business.industry, Wavelength range, Amplifier, Fibre amplifier, Energy conversion efficiency, General Physics and Astronomy, Cladding (fiber optics), Noise figure, business
Abstract

A high-power Er3+/Yb3+-codoped double-cladding all-fibre amplifier was successfully demonstrated and experimentally investigated. The amplifier could be operated with a maximum output power of 2.18 W and 2.11 W at 1541 nm and 1550 nm wavelengths, respectively, when the maximum pump power was 6.07 W. The power conversion efficiency was up to 35.6% and 34.4% at the two wavelengths, respectively. The output power and the gain were greater than 2.00 W and 20.0 dB, respectively, in the wavelength range from 1539 nm to 1565 nm for 20.0 mW input signal power. The gain fluctuation and the noise figure around 1550 nm wavelength were less than 0.3 dB and 6.0 dB, respectively.

Published
2005

184. Development, safety and efficacy of a novel circular-irrigated deca-channel mapping and ablation catheter for pulmonary vein isolation.

Author

Feng, Xiang-Fei, Chen, Mu, Sun, Jian, Sun, Jie, Liang, Bo, Sun, Yi-Yong, and Li, Yi-Gang

Subjects
PULMONARY veins, CATHETER ablation, ATRIAL fibrillation, TISSUE wounds, CATHETERIZATION
Abstract

Background: Pulmonary vein isolation (PVI), a cornerstone for catheter ablation of atrial fibrillation (AF), remains a complex and time-consuming procedure. Present study introduces a novel, circular-irrigated, deca-channel mapping and ablation catheter (CIDMA), describes the in vitro test results on feasibility, safety, and acute efficacy of the CIDMA catheter.Methods: An assembled CIDMA catheter was subjected to a number of in vitro tests. With this catheter, ablation procedures were first performed in a pig's myocardial strips in vitro to determine the effects in unipolar or bipolar configuration.Results: Three catheters were assembled. The adjustable circular diameter was changed from initial state of 32.41 ± 0.61 mm into controlled state of 28.61 ± 0.47 mm (P = 0.013). In the plastic model, the push-ability, torque-ability, and kink resistance of CIDMA catheter were shown to be satisfactory. In vitro, our findings showed that ablation could produce obvious ablation lesions, and unipolar ablation (at length, width and depth of 5.0 ± 1.3, 4.6 ± 0.7, and 4.2 ± 0.6 mm, respectively) was more effective than bipolar (at length, width and depth of 2.8 ± 0.2, 4.2 ± 0.5, and 2.3 ± 0.4 mm, respectively) (P < 0.01).Conclusions: In vitro, our preliminary data suggest that the CIDMA catheter produced optimal ablation lesions, especially in the unipolar ablation mode. Future in vivo animal and clinical studies are warranted to test the efficacy of this catheter in real-world scenario. [ABSTRACT FROM AUTHOR]

Published
2018
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185. ICaL and Ito mediate rate-dependent repolarization in rabbit atrial myocytes.

Author

Hou, Jian-Wen, Li, Wei, Fei, Yu-Dong, Chen, Yi-He, Wang, Qian, Wang, Yue-Peng, and Li, Yi-Gang

Abstract

Rate-dependent repolarization (RDR) of action potential (AP) in cardiomyocyte plays a critical role in the genesis of arrhythmias and RDR in atrium has been linked with atrial fibrillation. However, detailed studies focusing on the role of RDR in rabbit atrium are scant. In this study, atrial cells were isolated from rabbit heart and rate-dependent property was explored in single atrial cell to elucidate the underlying mechanism. Our results indicated that rate-dependent prolongation was evident at the action potential duration at 20% (APD20) and 50% (APD50) repolarization but not at 90% repolarization (APD90) under control condition. Using transient outward potassium current (Ito) inhibitor 4-Aminopyridine (4-AP, 2 mM) effectively eliminated the changes in APD20 and APD50, and unmasked the rate-dependent reduction of APD90 which could be diminished by further adding L-type calcium current (ICaL) inhibitor nifedipine (30 μM). However, using the selective late sodium current (INaL) inhibitor GS-458967 (GS967, 1 μM) caused minimal effect on APD90 of atrial cells both in the absence and presence of 4-AP. In consistence with results from APs, Ito and ICaL displayed significant rate-dependent reduction because of their slow reactivation kinetics. In addition, the magnitude of INaL in rabbit atrium was so small that its rate-dependent changes were negligible. In conclusion, our study demonstrated that Ito and ICaL mediate RDR of AP in rabbit atrium, while minimal effect of INaL was seen. [ABSTRACT FROM AUTHOR]

Published
2018
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186. Optimal stealthy false data injection attacks in cyber-physical systems.

Author

Li, Yi-Gang and Yang, Guang-Hong

Subjects
*CYBERTERRORISM, *GAUSSIAN distribution, *SAMPLING errors, *MATHEMATICAL optimization, *SIMULATION methods & models
Abstract

Highlights • A more general innovation based linear attack strategy based on Gaussian distribution with an arbitrary mean is proposed. • The estimation error covariance recursion is derived which is more complicated than the one under zero-mean Gaussian distributed attacks. • A new characterization of the degradation of the estimation performance is given by summing the trace of the error covariance in a finite time horizon. • The optimal attack strategy is obtained by solving a constrained quadratic optimization problem which is different from the standard convex optimization problems in the existing results. Abstract In this paper, the problem of false data injection attacks for cyber-physical systems is investigated. The Kullback–Leibler divergence is utilized to measure the stealthiness of the attacks. Different from the existing attack policies which are required to be zero-mean Gaussian distributed, a more general linear attack strategy based on Gaussian distribution with an arbitrary mean is proposed. Under the framework of the attacks, the degradation of system performance is analyzed by utilizing the statistical characteristics of the measurement innovation, and the optimal attack strategy is obtained by employing the Lagrange multiplier method to solve a constrained quadratic optimization problem. It is proved that the developed attack scheme can achieve the largest remote estimation error and guarantee the attack stealthiness simultaneously. Finally, simulation examples are provided to demonstrate the theoretical results. [ABSTRACT FROM AUTHOR]

Published
2019
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187. Experimental Investigation on Cooling/Heating Characteristics of Ultra-Thin Micro Heat Pipe for Electric Vehicle Battery Thermal Management

Author

Liu, Fei-Fei, Lan, Feng-Chong, Chen, Ji-Qing, and Li, Yi-Gang

Abstract

Due to the heat pipes’ transient conduction, phase change and fluid dynamics during cooling/heating with high frequency charging/discharging of batteries, it is crucial to investigate in depth the experimental dynamic thermal characteristics in such complex heat transfer processes for more accurate thermal analysis and design of a BTMS. In this paper, the use of ultra-thin micro heat pipe (UMHP) for thermal management of a lithium-ion battery pack in EVs is explored by experiments to reveal the cooling/heating characteristics of the UMHP pack. The cooling performance is evaluated under different constant discharging and transient heat inputs conditions. And the heating efficiency is assessed under several sub-zero temperatures through heating films with/without UMHPs. Results show that the proposed UMHP BTMS with forced convection can keep the maximum temperature of the pack below 40 °C under 1 ~ 3C discharging, and effectively reduced the instant temperature increases and minimize the temperature fluctuation of the pack during transient federal urban driving schedule (FUDS) road conditions. Experimental data also indicate that heating films stuck on the fins of UMHPs brought about adequate high heating efficiency comparing with that stuck on the surface of cells under the same heating power, but has more convenient maintenance and less cost for the BTMS. The experimental dynamic temperature characteristics of UMHP which is found to be a high-efficient and low-energy consumption cooling/heating method for BTMSs, can be performed to guide thermal analysis and optimization of heat pipe BTMSs.

Published
2018
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188. High Birefringence in Graphene Structure Photonic Crystal Fiber

Author

范万德 Fan Wan-de, 吴宵宵 Wu Xiao-xiao, 廖文英 Liao Wen-ying, 李乙钢 Li Yi-gang, 唐文海 Tang Wen-hai, 曹学伟 Cao Xue-wei, and 隋佳男 Sui Jia-nan

Subjects
Materials science, Birefringence, business.industry, Graphene, 02 engineering and technology, Microstructured optical fiber, 021001 nanoscience & nanotechnology, 01 natural sciences, Yablonovite, Atomic and Molecular Physics, and Optics, law.invention, law, 0103 physical sciences, Optoelectronics, 010306 general physics, 0210 nano-technology, business, Photonic crystal, Photonic-crystal fiber
Published
2016

189. Experimental and Numerical Analysis of a Two-Order Cascaded Raman Fibre Laser

Author

Dong Xiao-Yi, LI Yi-Gang, LU Ke-Cheng, Chi Rong-Hua, and SU Hong-Xin

Subjects
Materials science, business.industry, Numerical analysis, Slope efficiency, Physics::Optics, General Physics and Astronomy, Order (ring theory), Power (physics), Subwavelength-diameter optical fibre, symbols.namesake, Optics, Fiber laser, symbols, business, Raman spectroscopy
Abstract

A two-order cascaded Raman fibre laser based on GeO2-SiO2 fibre and fibre Bragg gratings is fabricated. Output power 309 mW of the second Stokes light around 1176.2 nm is obtained with a slope efficiency of 45.3%. The experimental results agree well with the simulation results obtained by using the double-pass model.

Published
2003

190. Modulation Spectroscopy of GaAs Covered by InAs Quantum Dots

Author

Li Cheng-Ming, Zhang Zi-Yang, Zhang Cun-zhou, Xu Bo, Liu Feng-Qi, Qu Shengchun, Jin Peng, LI Yi-Gang, Meng Xian-Quan, Pan Shi-Hong, and Wang Zhan-Guo

Subjects
Materials science, Condensed matter physics, Condensed Matter::Other, business.industry, Fermi level, General Physics and Astronomy, Condensed Matter::Mesoscopic Systems and Quantum Hall Effect, Condensed Matter::Materials Science, symbols.namesake, Quantum dot, Monolayer, Microscopy, symbols, Modulation spectroscopy, Optoelectronics, Condensed Matter::Strongly Correlated Electrons, business, Layer (electronics), Deposition (law), Wetting layer
Abstract

Contactless: electroreflectance has been employed at room temperature to study the Fermi level pinning at undoped-n(+) GaAs surfaces covered by 1.6 and 1.8 monolayer (ML) InAs quantum dots (QDs). It is shown that the 1.8 ML InAs QD moves the Fermi level at GaAs surface to the valence band maximum by about 70 meV compared to bare GaAs, whereas 1.6 ML InAs on GaAs does not modify the Fermi level, It is confirmed that the modification of the 1.8 ML InAs deposition on the Fermi level at GaAs surface is due to the QDs, which are surrounded by some oxidized InAs facets, rather than the wetting layer.

Published
2002

191. Yb 3+ -Doped Double-Clad Fibre Laser Pumped by Rectangular Inner Cladding

Author

Sun Jian-Jun, Yuan Shu-Zhong, Huang Bang-Cai, Ning Ding, Dong Xiao-Yi, Lu Kecheng, and Li Yi-Gang

Subjects
Materials science, business.industry, Slope efficiency, Doping, General Physics and Astronomy, Chemical vapor deposition, Cladding (fiber optics), Laser, law.invention, Wavelength, Optics, Machining, law, Fiber laser, Optoelectronics, business
Abstract

A novel Yb3+-doped double-clad silica fibre with rectangular inner cladding was designed and developed by using the modified chemical vapour deposition process, solution-doping and optical machining all together. The dimensions of the inner cladding are 100×70 µm, and Yb3+-doped concentration in the core is about 0.24 wt.%. The operation of the fibre laser pumped by inner cladding is reported. The threshold of the laser is 34 mW. When the pump power launched is 141 mW, the laser output is 84 mW at the wavelength 1075.6 nm, and the slope efficiency is 77%.

Published
2001

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