Methylprednisolone as Adjunct to Endovascular Thrombectomy for Large-Vessel Occlusion Stroke

Importance It is uncertain whether intravenous methylprednisolone improves outcomes for patients with acute ischemic stroke due to large-vessel occlusion (LVO) undergoing endovascular thrombectomy. Objective To assess the efficacy and adverse events of adjunctive intravenous low-dose methylprednisolone to endovascular thrombectomy for acute ischemic stroke secondary to LVO. Design, Setting, and Participants This investigator-initiated, randomized, double-blind, placebo-controlled trial was implemented at 82 hospitals in China, enrolling 1680 patients with stroke and proximal intracranial LVO presenting within 24 hours of time last known to be well. Recruitment took place between February 9, 2022, and June 30, 2023, with a final follow-up on September 30, 2023.InterventionsEligible patients were randomly assigned to intravenous methylprednisolone (n = 839) at 2 mg/kg/d or placebo (n = 841) for 3 days adjunctive to endovascular thrombectomy. Main Outcomes and Measures The primary efficacy outcome was disability level at 90 days as measured by the overall distribution of the modified Rankin Scale scores (range, 0 [no symptoms] to 6 [death]). The primary safety outcomes included mortality at 90 days and the incidence of symptomatic intracranial hemorrhage within 48 hours. Results Among 1680 patients randomized (median age, 69 years; 727 female [43.3%]), 1673 (99.6%) completed the trial. The median 90-day modified Rankin Scale score was 3 (IQR, 1-5) in the methylprednisolone group vs 3 (IQR, 1-6) in the placebo group (adjusted generalized odds ratio for a lower level of disability, 1.10 [95% CI, 0.96-1.25]; P = .17). In the methylprednisolone group, there was a lower mortality rate (23.2% vs 28.5%; adjusted risk ratio, 0.84 [95% CI, 0.71-0.98]; P = .03) and a lower rate of symptomatic intracranial hemorrhage (8.6% vs 11.7%; adjusted risk ratio, 0.74 [95% CI, 0.55-0.99]; P = .04) compared with placebo. Conclusions and Relevance Among patients with acute ischemic stroke due to LVO undergoing endovascular thrombectomy, adjunctive methylprednisolone added to endovascular thrombectomy did not significantly improve the degree of overall disability.Trial RegistrationChiCTR.org.cn Identifier: ChiCTR210005172

Torque Ripple Suppression of Brushless DC Motor Drive System Based on Improved Harmonic Injection Active Disturbance Rejection Control

The positioning accuracy and speed stability of the brushless DC motor (BLDC motor), as the drive element of the optomechanically scanned system (OMSS), are closely interrelated to the final imaging quality of the system. Active disturbance rejection control (ADRC) with strong anti-interference ability, fast response and good robustness is one of the extensively used control strategies. However, the performance of ADRC working in a complicated environment will be limited due to the controller structure, parameter tuning and the influence of multi-source nonlinear disturbance. Therefore, an improved ADRC method is proposed, which can switch between ‘point-to-point control mode’ and ‘stable speed control mode’ according to the system requirements. To further suppress the torque ripple and improve the control performance of the system, an improved harmonic injection scheme is added, and the parameters of improved ADRC are tuned by a slime mould algorithm based on a Levy flight operator (LF-SMA). The stability of the proposed ADRC is proved by Lyapunov stability theory. The experimental results show that the proposed control scheme could be available to reduce the torque ripple of the system

Torque Ripple Suppression of Brushless DC Motor Drive System Based on Improved Harmonic Injection Active Disturbance Rejection Control

The positioning accuracy and speed stability of the brushless DC motor (BLDC motor), as the drive element of the optomechanically scanned system (OMSS), are closely interrelated to the final imaging quality of the system. Active disturbance rejection control (ADRC) with strong anti-interference ability, fast response and good robustness is one of the extensively used control strategies. However, the performance of ADRC working in a complicated environment will be limited due to the controller structure, parameter tuning and the influence of multi-source nonlinear disturbance. Therefore, an improved ADRC method is proposed, which can switch between ‘point-to-point control mode’ and ‘stable speed control mode’ according to the system requirements. To further suppress the torque ripple and improve the control performance of the system, an improved harmonic injection scheme is added, and the parameters of improved ADRC are tuned by a slime mould algorithm based on a Levy flight operator (LF-SMA). The stability of the proposed ADRC is proved by Lyapunov stability theory. The experimental results show that the proposed control scheme could be available to reduce the torque ripple of the system

Synthesis of water-free PEDOT with polyvinylpyrrolidone stabilizer in organic dispersant system

Poly (3, 4-ethylenedioxythiophene): tosylate (PEDOT: Tos) is synthesized by chemical oxidative polymerization with polyvinylpyrrolidone (PVP) as stabilizer in organic solvent. The effects of different molecular weight and additive amount of PVP stabilizer, various volume ratios of propylene carbonate (PC) to ethanol in organic system, different oxidative agents and various polymerization temperature/ time on as-prepared PEDOT dispersion are taken into consideration and investigated systematically. Fourier transform infrared spectroscopy (FT-IR), film-forming property and electrical conductivity are studied and compared among different reaction conditions. The optimal polymerization scenario is to prepare PEDOT particles with 2 wt.% PVP (M.w. = 58,000) stabilizer and Fe-2(SO4)(3) oxidant at 80 degrees C for 24 h in organic system of PC and ethanol (volume ratio = 1: 3). Optimal PEDOT with PVP possesses more homogeneous particle size, better particle-particle connectivity in film and higher electrical conductivity (1.67* 10(-2) s cm(-1)) than that of PEDOT without PVP (5.2* 10(-4) s cm(-1)) and commercial organic PEDOT (4.7* 10(-4) s cm(-1)). The morphology and elemental composition of PEDOT particles with PVP are also investigated and compared with that of commercial organic PEDOT and aqueous PEDOT/PSS dispersion

Investigation on xanthan gum as novel water soluble binder for LiFePO4 cathode in lithium-ion batteries

Xanthan Gum (XG) is systematically investigated and employed as water soluble binder for LiFePO4 (LFP) cathode in Li-ion batteries. XG binder exhibits good thermal stability and processes abundant functional groups such as carboxyl and hydroxyl, displaying a better adhesion strength of 0.085 N cm(-1) than sodium carboxymethyl cellulose (CMC, 0.050 N cm(-1)), but inferior to polyvinylidene difluoride (PVDF, 0.170 N cm(-1)). The Rheology test reveals that the viscosity of LFP slurry prepared with XG binder is higher than that of PVDF, resulting in a better dispersion of LFP and carbon black particles. The electrochemical performances of LFP-XG electrode are investigated and compared with those of aqueous CMC and conventional PVDF binder. LFP-XG displays better cycle stability and rate performance than PVDF, comparable to CMC, which retains 55.3% capacity of C/5 at 5 C as compared to PVDF (34.8%) and CMC (57.8%). Cyclic voltammetry (CV) shows that LFP-XG has smaller redox polarization and faster lithium diffusion rate than PVDF while electrochemical impedance spectroscopy (EIS) measurement at specified intervals reveals its more favorable electrochemical kinetics than that with PVDF, similar to CMC, thus better rate capability. Scanning electron microscopy (SEM) displays that LFP-XG has a more homogenous distribution of LFP and conductive carbon black particles with XG before cycling and better maintains its structure integrity after 100 cycles than that of PVDF. Furthermore, LFP-XG is observed to process a high ionic conductivity supported by dQ/dV profiles. (C) 2017 Elsevier B.V. All rights reserved

Cyanoethylated Carboxymethyl Chitosan as Water Soluble Binder with Enhanced Adhesion Capability and electrochemical performances for LiFePO4 Cathode

Cyanoethylated carboxymethyl chitosan (CN-CCTS) has been synthesized through a straightforward cyanoethylation reaction by reacting CCTS with acrylonitrile in NaOH aqueous solution. CN-CCTS shows improved adhesion strength of 0.047 N/cm as compared with 0.013 N/cm for CCTS after introducing cyanoethyl group in the chemical structure of CCTS. The electrochemical performances of LiFePO4 electrode with CN-CCTS binder have been investigated and compared with those using water soluble sodium carboxymethyl cellulose (CMC) and non-aqueous polyvinylidene difluoride (PVDF) binder. LiFePO4 electrode with CN-CCTS exhibits better cycling stability and rate capability, retaining 56.3% capacity of C/5 at 5C rate as compared with 48.4% and 32.8% for CMC and PVDF, respectively. Cyclic voltammetry and electrochemical impedance spectroscopy measurement reveal that LiFePO4 electrode with CN-CCTS has a more favorable electrochemical kinetics than that with CMC and PVDF, thus better rate capability. (C) 2015 Elsevier Ltd. All rights reserved

Acceleration Level Control of Redundant Manipulators with Physical Constraints Compliance and Disturbance Rejection under Complex Environment

Investigation of joint torque constraint compliance is of significance for robot manipulators especially working in complex environments. A lot of which is attributed to that, on the one hand, it is beneficial to the improvement of both safety and reliability of the mission execution. On the other hand, the energy consumption required by the robot to complete the desired mission can be reduced. Most existing schemes do not take the joint torque limit and other inherent physical structure limits in a manipulator into account at the same time. In addition, many unavoidable uncertainties such as the external environmental disturbance and/or electromagnetism interferences in the circuit system may influence the accuracy and effectiveness of the task execution for a robot. In this study, we cast light on the acceleration level control of redundant robot manipulators considering both four physical constraint limits and interference rejection. A robust unified quadratic-programming-based hybrid control scheme is proposed, where the joint torque constraints are converted as two inequality constraints based on the robots’ dynamics equation. A recurrent-neural-network-based controller is designed for solving the control variable. Numerical experiments performing in PUMA 560 manipulator and planer manipulator illustrate that a rational torque distribution is obtained among the joints and the considered physical structural vectors are all restricted to the respective constraint range. In addition, even disturbed by the noise, the manipulator still successfully tracks the desired trajectory under the proposed control scheme