Suboptimal reliable guaranteed cost control for continuous-time systems with multi-criterion constraints

The suboptimal reliable guaranteed cost control (RGCC) with multi-criterion constraints is investigated for a class of uncertain continuous-time systems with sensor faults. A fault model in sensors, which considers outage or partial degradation of sensors, is adopted. The influence of the disturbance on the quadratic stability of the closed-loop systems is analyzed. The reliable state-feedback controller is developed by a linear matrix inequalities (LMIs) approach, to minimize the upper bound of a quadratic cost function under the conditions that all the closed-loop poles be placed in a specified disk, and that the prescribed level of H∞ disturbance attenuation and the upper bound constraints of control inputs’ magnitudes be guaranteed. Thus, with the above multi-criterion constraints, the resulting closed-loop system can provide satisfactory stability, transient property, a disturbance rejection level and minimized quadratic cost performance despite possible sensor faults.

The role of DJ-1 in the pathogenesis of Parkinson’s disease

Parkinson’s disease (PD) is a slowly progressive neurodegenerative disorder characterized clinically by bradykinesia, rigidity, tremor, gait dysfunction, and postural instability. Several genes have been identified for monogenic disorders that variably resemble Parkinson’s disease. Here, we focus on PARK7, a gene relates to an autosomal recessive form of early-onset Parkinsonism and encodes a protein named DJ-1. Though the exact role of DJ-1 needs to be elucidated, it is generally thought to be functioned as a molecular chaperone and an oxidative sensor (or antioxidative factor). We will review the protective role of DJ-1 to prevent dopaminergic neurons in the substantia nigra pars compacta (SNpc) from degeneration and how its dysfunction would lead to neurodegeneration.

One-stop strategy for treatment of atrial fibrillation:feasibility and safety of combining catheter ablation and left atrial appendage closure in a single procedure

Background:Catheter ablation is effective in restoring sinus rhythm and left atrial appendage closure(LAAC)is increasingly used for stroke prevention in patients with atrial fibrillation(AF).We aimed to observe the feasibility and safety of performing AF ablation and LAAC in a single(one-stop)procedure.Methods:Consecutive AF patients who underwent the combined procedure of AF ablation and LAAC with WATCHMAN device between March 2017 and September 2018 were prospectively enrolled.Baseline and intra-procedural parameters were evaluated.Three-month and subsequent 1-year follow-up were performed in all and earlier-enrolled subjects,respectively.Results:A total of 178 AF patients(94 males,68.9±8.1 years)underwent the one-stop procedure with CHA2DS2-VASc score 3.3±1.5 and HAS-BLED score 1.6±1.0,respectively.Pulmonary vein isolation was achieved in all patients while additional linear ablation was applied if the operator deemed necessary,yielding immediate ablation success rate of 98.9%(176/178).In the subsequent LAAC,satisfactory seal(residual leak<5 mm)was achieved in all patients.One stroke and four cardiac perforations occurred peri-operatively.At 3-month follow-up,sinus rhythm and satisfactory seal were maintained in 153/178(86.0%)and 178/178(100%)patients,respectively.One stroke and one delayed cardiac tamponade occurred,while no device-related thrombus or device migration was observed.During the 1-year follow-up for the earlier enrolled subjects,52/72(72.2%)of the patients maintained sinus rhythm.There was no stroke or systemic embolism observed.Conclusion:Combining catheter ablation and LAAC in a single procedure can be successfully and safely performed in non-valvular AF patients of Chinese population.

Nucleation Analysis of Variant Transformed from Austenite with Σ_(3) Boundary in High-Strength Low-Alloy Steel

We elucidate here the effects of annealing twins on phase transformation products based on electron back-scatter diffraction analysis and corresponding microstructure visualization and quantification methods.Martensite and bainite were obtained by rapid continuous cooling and isothermal processing at different temperatures,respectively,which were designed to study variants formed in austenite with Σ_(3) boundary.The isothermal transformation near martensite start(M_(s))temperature was most conducive in obtaining the highest content of twin-related V_(1)/V_(2) variant pair.Based on the classical nucleation theory of martensite and bainite,respectively,the role of austenite Σ_(3) boundary in martensite and bainite transformation is illustrated.

Tailoring Variant Pairing to Enhance Impact Toughness in High-Strength Low-Alloy Steels via Trace Carbon Addition

Alloying can make conventional metals reach ultra-high strength,but this usually comes at dramatic loss of toughness.In this work,a desirable strength–toughness combination in high-strength low-alloy steel achieved via trace carbon addition.The significance of carbon in tailoring variant pairing and tuning impact toughness was elucidated from the perspective of crystallography and thermodynamics.As the carbon content increases,the packets and blocks are refined,and the-40 impact toughness improves.The enhancement of impact toughness results from the higher density of block boundaries,and the fracture mode shifts from brittle fracture to ductile–brittle combined fractures,then to ductile fracture due to the increased carbon.Increasing the carbon content would lower the martensite start temperature(M_S)temperature and driving force for martensitic transformation,and increase the strength of austenite matrix,which in turn contributes to producing more V1/V2 variant pairs to accommodate the transformation strain.