Preliminary study of beta-blocker therapy on modulation of interleukin-33/ST2 signaling during ventricular remodeling after acute myocardial infarction

Background: This study aimed to evaluate the role of b-blocker therapy on modulating interleukin (IL)-33/ST2 (interleukin-1 receptor-like 1) signaling during ventricular remodeling related to heart failure (HF) after acute myocardial infarction (AMI). Methods: Sprague-Dawley rats that survived surgery to induce AMI were randomly divided into the placebo group and the b-blocker treatment group. A sham group was used as a control. Left ventricular (LV) function variables, the myocardial infarct size, fibrosis and IL-33/ST2 protein expression was measured. Results: Compared with the placebo group, b-blocker treatment significantly improved LV function and reduced infarct size (p < 0.05). There was higher protein expression of IL-33 (p < 0.05) and sST2 (p < 0.05), as well as higher expression of fibrosis (p < 0.05), compared to the sham group. Notably, the high expression of cardioprotective IL-33 was not affected by b-blocker treatment (p > 0.05), however, treatment with b-blocker enhanced IL-33/ST2 signaling, with lower expression of sST2 (p < 0.05) and significantly attenuated fibrosis (p < 0.05). Conclusions: Our study suggested that b-blocker therapy might play a beneficial role in the modula­tion of IL-33/ST2 signaling during ventricular remodeling. These results may be helpful in identifying IL-33/ST2 systems as putative b-blocker targets at an early stage after AMI. (Cardiol J 2017; 24, 2: 188–194

Frequency regulation strategy of direct drive permanent magnet synchronous wind power generation system based on RPC principle

The continuous integration of renewable energy into the grid has reduced its inertia and damping levels. When disturbances occur, the grid is prone to frequency excursion issues, which restrict the further utilization of renewable energy. Consequently, an increasing number of grid codes require active participation of renewable energy sources in the system’s frequency regulation (FR). Direct-drive permanent magnet synchronous wind power systems, characterized by their simple structure and high reliability, have gradually become the mainstream in wind power systems. By controlling the pitch angle to reserve surplus power, the wind turbines can actively engage in frequency regulation during disturbances. However, due to limited power reserve capacity, traditional FR methods struggle with parameters tuning, thus failing to achieve the desired effect. To this end, this paper proposes an FR strategy for direct-drive permanent magnet synchronous wind power systems based on the principle of rapid power compensation (RPC). It circumvents the challenges associated with parameter tuning, and achieves optimal FR performance for wind turbine inverter under power-limited conditions. Firstly, it is demonstrated that the proposed RPC control, when making full use of power reserves, can achieve FR effects equivalent to optimal PD control through rigorous mathematical analysis. Subsequently, the RPC control is divided into four operating modes to address FR requirements under different conditions. The transitions between these modes are explained, and the detailed implementation of the RPC control is provided. Finally, the effectiveness and superiority of the proposed control strategy are validated through simulation based on Matlab/Simulink

Two-year longitudinal evaluation of a second-generation thin-strut sirolimus-eluting bioresorbable coronary scaffold with hybrid cell design in porcine coronary arteries

Background: The first commercially available bioresorbable scaffold (BRS) had a strut thickness of 156 microns. As such, it had the potential for delivery challenges and higher thrombogenicity. The aim herein, is to evaluate biomechanical performance, pharmacokinetics and vascular healing of a novel thin strut (100 μm) sirolimus eluting BRS (MeRes-100, Meril Life Sciences, Gujarat, India) against the once clinically used BRS (Absorb BVS, Abbott, Santa Clara, CA) in porcine coronary arteries. Methods: Following device implantation, angiographic and optical coherence tomography (OCT) evaluation were performed at 45, 90, 180 days, 1 year and 2 years. Histological evaluation was per­formed at 30, 90 and 180 days. Results: At 2 years, both lumen (MeRes-100 7.07 ± 1.82 mm2 vs. Absorb BVS 7.57 ± 1.39 mm2, p = NS) and scaffold areas (MeRes-100 9.73 ± 1.80 mm2 vs. Absorb BVS 9.67 ± 1.25 mm2, p = NS) were comparable between tested and control scaffolds. Also, the late lumen area gain at 2 years was similar in both groups tested (MeRes-100 1.03 ± 1.98 mm2 vs. Absorb BVS 0.85 ± 1.56 mm2, p = NS). Histologic examination up to 6 months showed comparable healing and inflammation profiles for both devices. Conclusions: The novel sirolimus-eluting BRS with thinner struts and hybrid cell design showed similar biomechanical durability and equivalent inhibition of neointimal proliferation when compared to the first-ever Absorb BVS up to 2 years in normal porcine coronary arteries

Capacity optimization configuration of live gas storage system in independent power systems

As the energy demand and the continuous improvement of environmental performance continuous grow, the use of Independent Power Systems (IPS) is becoming increasingly common. Energy storage facilities not only achieve reliable power supply through IPS, but also face the problem of how to achieve more efficient and energy-saving. Therefore, this paper chose to establish a charged gas storage system (GSS for short here) of an independent power system to establish the mathematical model of the GSS through the Linear programming model, including the energy balance equation of the GSS and the load balance equation of the power system. It then used genetic algorithm (GA) to optimize the capacity of the GSS and obtained the optimal capacity configuration plan. In the simulation experiment analysis of a live GSS in view of GA for capacity optimization configuration, the live GSS proposed in this paper outperformed traditional GSS and battery GSS in terms of performance, power load, energy conversion, and capacity configuration. In terms of power load, the six indexes of regulation capacity, response speed, stability, discharge efficiency, power density and energy storage capacity are compared. Among them, the system capacity designed in this paper is 90, 83, 97, 83 and 90 % respectively, which are much higher than the other two. Among them, the six dimensional power load capacity was outstanding, and the energy conversion efficiency was also around 80 %. The capacity configuration was distributed between 85 and 94. This article proposed a design scheme for an electrified GSS based on GA for capacity optimization configuration, which can better meet the needs of independent power systems and improve their reliability and stability

Evaluation of Long-Term Inflammatory Responses after Implantation of a Novel Fully Bioabsorbable Scaffold Composed of Poly-L-lactic Acid and Amorphous Calcium Phosphate Nanoparticles

Objectives. Our previous studies have confirmed the superior biocompatibility of the poly-L-lactic acid/amorphous calcium phosphate (PLLA/ACP) scaffolds compared to PLLA scaffolds at 1-month. In the present study, the long-term inflammatory responses of PLLA/ACP scaffolds in a porcine coronary model have been explored. Methods. The 24 PLLA scaffolds and 24 PLLA/ACP scaffolds were implanted into the coronary arteries of 24 miniature pigs. Serum levels of ALT, AST, and CRP were measured before operation, as well as 1-month, 6-months, 12-months, and 24-months. The vascular segments were taken for pathomorphological observation. HE staining was used for the inflammatory score and fibrosis score. Immunohistochemical staining detected positive expression indexes of MMP-9 and NF-κB. The expression of inflammation-related proteins of IL-1 and IL-6 was detected by Western Blot in surrounding tissues of scaffolds. Results. There was no significant difference between the two groups in ALT, AST, and UR at different time points (P<0.05). The inflammation score in the PLLA/ACP group was lower than that in the PLLA group at 6-months, 12-months, and 24-months (P<0.05), and the fibrosis score was reduced in the PLLA/ACP group than that in the PLLA group at 12-months and 24-months (P<0.05). The expression of MMP-9 and NF-κB in the PLLA/ACP group was significantly less than that in the PLLA group at 6-months, 12-months, and 24-months (P<0.05). The protein expression of IL-1 in the PLLA/ACP group was decreased than that in the PLLA group at 12-months and 24-months (P<0.05). Furthermore, the protein expression of IL-1 was significantly lower than that in the PLLA group at 6-months, 12-months, and 24-months (P<0.01). Conclusions. The supplement of ACP nanoparticles can effectively reduce the long-term inflammatory reaction caused by PLLA and has good safety and biocompatibility. The novel bioabsorbable PLLA/ACP scaffold provides reliable guidance for the development and clinical application of bioabsorbable scaffolds in the future