Sliding Mode Control for Bearingless Induction Motor Based on a Novel Load Torque Observer

For the problem of low control performance of Bearingless Induction Motor (BIM) control system in the presence of large load disturbance, a novel load torque sliding mode observer is proposed on the basis of establishing sliding mode speed control system. The load observer chooses the speed and load torque of the BIM control system as the observed objects, uses the speed error to design the integral sliding mode surface, and adds the low-pass filter to reduce the torque observation error. Meanwhile, the output of the load torque is used as the feedforward compensation for the control system, which can provide the required current for load changes and reduce the adverse influence of disturbance on system performance. Besides, considering that the load changes lead to the varying rotational inertia, the integral identification method is adopted to identify the rotational inertia of BIM, and the rotational inertia can be updated to the load observer in real time. The simulation and experiment results all show that the proposed method can track load torque accurately, improve the ability to resist disturbances, and ameliorate the operation quality of BIM control system. The chattering of sliding mode also is suppressed effectively

Sliding Mode Variable Structure Control of a Bearingless Induction Motor Based on a Novel Reaching Law

In order to improve the performance of the Bearingless Induction Motor (BIM) under large disturbances (such as parameter variations and load disturbances), an adaptive variable-rated sliding mode controller (ASMC) is designed to obtain better performance of the speed regulation system. Firstly, the L 1 norm of state variables is applied to the conventional exponential reaching law and an adaptive variable-rated exponential reaching law is proposed to reduce system chattering and improve bad convergence performance of the sliding mode variable structure. Secondly, an integral sliding-mode hyper plane is produced according to the speed error in speed regulation system of BIM. Current signal is extracted by the combination of the sliding-mode hyper plane, the electromagnetic torque and the equation of motion. Finally, the feedback speed can adjust operating state adaptively according to speed error and make system chattering-free moving. The simulation and experiment results show that the proposed ASMC can not only enhance the robustness of the system’s uncertainties, but also improve the dynamic performance and suppress system chattering

Metabonomics on Candida albicans

ABSTRACTDevelopment of antifungal agents with novel mechanism and low toxicity are essential due to the prevalence of the infectious diseases caused by Candida albicans. The current study employed a new research method, which combined the ultra-high performance liquid chromatography with quadrupole time-of-flight mass spectrometry and gas chromatography-mass spectrometry, to investigate the intrinsic mechanism of Shikonin (SK) against C. albicans. The levels of 27 metabolites, which mainly involved in histone deacetylation, amino acid synthesis, lipid synthesis, nitrogen metabolism, tricarboxylic acid cycle, oxidative stress and glycolysis, were remarkably changed upon SK treatment. Specially, the down-regulation of nicotinamide (NAM) upon SK treatment indicated the suppression of the deacetylation of the histone H3 on lysine 56 residue (H3K56). Further experiment confirmed that the level of H3K56 acetylation (H3K56ac) was dramatically increased upon SK treatment which was mediated by HST3, the gene encoding the H3K56 deacetylase (Hst3p). Our results demonstrated that SK is the first natural compound reported to execute antifungal activity directly via boosting H3K56ac mediated by HST3. Importantly, this finding shed new light on the mechanisms to relieve the side effects or reverse the drug tolerance, as well as the development of agents for antifungal therapies

Related metabolites and their metabolic pathway.

<p>Related metabolites and their metabolic pathway.</p

Metabolomic profiling for the identification of potential biomarkers involved in a laboratory azole resistance in <i>Candida albicans</i>

<div><p><i>Candida albicans</i>, one of the most common fungal pathogens, is responsible for several yeast infections in human hosts, being resistant to classically used antifungal drugs, such as azole drugs. Multifactorial and multistep alterations are involved in the azole resistance in <i>Candida albicans</i>. In this study, a FCZ-resistant <i>C</i>. <i>albicans</i> strain was obtained by serial cultures of a FCZ-susceptible <i>C</i>. <i>albicans</i> strain in incrementally increasing concentrations of FCZ. We performed an integrated profile of different classes of molecules related to azole resistance in <i>C</i>. <i>albicans</i> by combining several mass-spectrometry based methodologies. The comparative metabolomic study was performed with the sensitive and resistant strains of <i>C</i>.<i>albicans</i> to identify metabolites altered during the development of resistance to fluconazole, while the intervention strains and non-intervention strains of <i>C</i>.<i>albicans</i> to identify metabolites altered involved in cross-resistant to azole drugs. Our analysis of the different metabolites identified molecules mainly involved in metabolic processes such as amino acid metabolism, tricarboxylic acid cycle and phospholipid metabolism. We also compared the phospholipid composition of each group, revealing that the relative content of phospholipids significantly changed during the development of resistance to azole drugs. According with these results, we hypothesized that the metabolism shift might contribute to azole drugs resistance in <i>C</i>.<i>albicans</i> from multifactorial alterations. Our result paves the way to understand processes underlying the resistance to azole drugs in <i>C</i>. <i>albicans</i>, providing the basis for developing new antifungal drugs.</p></div

The result of total number of carbons in the fatty acid chains of phosphoglyceride.

<p>The result of total number of carbons in the fatty acid chains of phosphoglyceride.</p

PLS-DA scores plot of extracellular metabolites from LC-Q-TOF/MS.

<p>(A)S group vs R group; (B)S group vs S+KCZ group; (C)R group vs R+KCZ group; (D)S+KCZ group vs R+KCZ group.</p

HILIC-QQQ/MS scan parameters.

<p>HILIC-QQQ/MS scan parameters.</p

The number of differential metabolites from each model.

<p>The number of differential metabolites from each model.</p