Search

This paper investigates the fault-tolerant prescribed performance control problem for a class of multiple-input single-output unknown nonlinear systems subject to process faults and actuator failures. In contrast to the related works, we consider a general class of nonlinear systems with both multiplicative nonlinearities and additive nonlinearities corrupted by the process faults; only the boundedness of the process faults and the continuity of the nonlinear functions are required, without the explicit or fixed structures of the fault functions. To conquer this problem, a less-demanding and low-complexity fault-tolerant prescribed performance control approach is proposed. The controller is independent of the specific information of faults or the system model and does not invoke fault diagnosis or neural/fuzzy approximation to acquire such knowledge. It achieves the reference tracking with the predefined rate and accuracy. A comparative simulation on a single-link robot is conducted to illustrate the effectiveness and superiority of the proposed approach. • Both process faults and actuator failures are considered. • The virtual control coefficients are time-varying nonlinear functions. • We consider a general class of systems with multiplicative and additive nonlinearities. • Both multiplicative and additive nonlinearities are impacted by process faults. • The reference tracking with predefined rate and accuracy is achieved. [ABSTRACT FROM AUTHOR]

Exercise-induced hypoalgesia refers to a reduction in pain sensitivity following a single bout of exercise, which has been shown to be diminished or impaired with aging and chronic pain. Exercise training (repeated bouts of exercise over time) is often recommended as a non-pharmacological treatment for chronic pain and age-related functional declines. However, whether exercise training can augment the exercise-induced hypoalgesia has not been well studied. The purpose of this paper is to 1) provide an overview of the existing literature investigating the effect of exercise training on the magnitude of exercise-induced hypoalgesia, and 2) discuss potential underlying mechanisms as well as considerations for future research. Given the paucity of randomized controlled trials in this area, the effects of exercise training on exercise-induced hypoalgesia are still unclear. Several potential mechanisms have been proposed to explain the impaired exercise-induced hypoalgesia in chronic pain and older individuals (e.g., endogenous opioid, cardiovascular, and immune system). Exercise training appears to induce physiological changes in those systems, however, further investigations are necessary to test whether this will lead to improved exercise-induced hypoalgesia. Future research should consider including a time- and age-matched non-training group and utilizing the same exercise protocol for testing exercise-induced hypoalgesia across intervention groups. • Performing a single bout of exercise leads to a reduction in pain sensitivity. • Exercise-induced hypoalgesia is impaired in individuals of age and those with chronic pain. • Exercise training may improve the magnitude of exercise-induced hypoalgesia. [ABSTRACT FROM AUTHOR]

To develop new inorganic multifunctional materials, a series of Yb3+/Er3+ doped precursor glasses (PGs) were fabricated through melt quenching technique, and a novel niobate transparent photoelectric glass ceramic (GC) was gained via controlled crystallization of PG. Compared with PG, the up-conversion (UC) luminescence performance is significantly increased in GC. Utilizing the temperature dependence of the emission intensity of Er3+ ions, the dual-mode optical temperature measurement is realized through fluorescence intensity ratio (FIR) methods. The ultimate absolute sensitivity (S a-max) and relative sensitivity (S r-max) based on the thermal/non-thermal coupling energy levels (TCELs/NTCELs) are 0.68 %K−1 and 0.85% K−1, respectively. Moreover, the single-layer capacitor made of GC can release energy density of 0.83 J/cm3 (@600 kV/cm) and power density of 210 MW/cm3. This work indicates that niobate transparent glass ceramics are expected to be applied in the optical thermometry and pulse energy storage field. [ABSTRACT FROM AUTHOR]

Diastolic dysfunction is regarded as an important predictor of outcome after liver transplantation (LT). We investigated the influence of liver disease severity on left ventricular diastolic properties using end-diastolic pressure-volume relationship (EDPVR) analysis in patients with end-stage liver disease (ESLD). Association between alterations of the EDPVR and mortality after LT was evaluated. In this observational retrospective cohort study, 3,211 patients who underwent LT for ESLD were included in analysis. Variables derived from single-beat EDPVR (diastolic stiffness-coefficient [β] and end-diastolic volume at an end-diastolic pressure of 20 mmHg [EDVI 20 ] indicating ventricular capacitance) were estimated using preoperative echocardiographic data. Alterations in EDPVR with increased stiffness (β > 6.16) were categorized into 3 groups; leftward-shifted (EDVI 20 <51 mL/m2), rightward-shifted (EDVI 20 > 69.7 mL/m2), and intermediate (EDVI 20 51-69.7 mL/m2). As the model for ESLD score increases, both EDVI 20 and β gradually increased, which indicated ventricular remodeling with larger capacitance and higher diastolic stiffness. Among patients with increased stiffness (β > 6.16, n = 1,090), survival rates after LT were lower in leftward-shifted EDPVR than in rightward-shifted EDPVR (73.7% vs 82.9%; log-rank P = 0.002). In the adjusted Cox proportional hazard model, risk of cumulative all-cause mortality at 11 years was the highest in leftward-shifted EDPVR (hazard ratio [HR]: 1.93; 95% confidence interval [CI]: 1.27-2.92), followed by intermediate EDPVR (HR: 1.55; 95% CI: 1.12-2.26), compared with rightward-shifted EDPVR. The SHapley Additive exPlanation model revealed that the variables associated with leftward-shifted EDPVR were diabetes, female sex, old age, and hypertension. As ESLD advances, diastolic ventricular properties are characterized by increased EDVI 20 and β on rightward-shifted EDPVR, indicating larger capacitance and higher stiffness. However, leftward-shifted EDPVR with left ventricle remodeling failure is associated with poor post-LT survival. [Display omitted] [ABSTRACT FROM AUTHOR]

Within-subject training models have become common within the exercise literature. However, it is currently unknown if training one arm with a high load would impact muscle size and strength of the opposing arm training with a low load. Parallel group. 116 participants were randomized to one of three groups that completed 6-weeks (18 sessions) of elbow flexion exercise. Group 1 trained their dominant arm only, beginning with a one-repetition maximum test (≤ 5 attempts), followed by four sets of exercise using a weight equivalent to 8–12 repetition maximum. Group 2 completed the same training as Group 1 in their dominant arm, while the non-dominant arm completed four sets of low-load exercise (30–40 repetition maximum). Group 3 trained their non-dominant arm only, performing the same low-load exercise as Group 2. Participants were compared for changes in muscle thickness and elbow flexion one-repetition maximum. The greatest changes in non-dominant strength were present in Groups 1 (Δ 1.5 kg; untrained arm) and 2 (Δ1.1 kg; low-load arm with high load on opposite arm), compared to Group 3 (Δ 0.3 kg; low-load only). Only the arms being directly trained observed changes in muscle thickness (≈ Δ 0.25 cm depending on site). Within-subject training models are potentially problematic when investigating changes in strength (though not muscle growth). This is based on the finding that the untrained limb of Group 1 saw similar changes in strength as the non-dominant limb of Group 2 which were both greater than the low-load training limb of Group 3. [ABSTRACT FROM AUTHOR]