A Modulated Model Predictive Control Scheme for the Brushless Doubly Fed Induction Machine

© 2013 IEEE. Brushless doubly fed induction machines (BDFIMs) feature some important advantages, such as high reliability and low maintenance cost, over alternative solutions for brushless machine applications. This paper proposes a modulated model predictive control (MPC) algorithm for BDFIMs, which achieves a fixed switching frequency and superior system performance. An improvement of power quality is shown in this paper when compared to the conventional finite-control set-MPC. This paper examines the design and implementation of the modulation technique as well as presenting the simulation and experimental results to verify the technique's operation

Genetic causal relationship between gut microbiome and psoriatic arthritis: a bidirectional two-sample Mendelian randomization study

BackgroundSeveral observational studies have suggested a potential relationship between gut microbiome and psoriatic arthritis (PsA). However, the causality of this relationship still remains unclear. We aim to explore if the specific gut microbiome is causally associated with PsA at the genetic level and offer valuable insights into the etiology of PsA.MethodsIn this study, we employed a bidirectional two-sample Mendelian randomization (MR) analysis to investigate the causal effects of the gut microbiome on PsA. Publicly accessible genome-wide association study summary data of gut microbiome were obtained from the MiBioGen consortium (n = 14,306), while the summary statistics of psoriatic arthropathies were sourced from the FinnGen consortium R8 release data (2,776 cases and 221,323 controls). The primary analytical method employed was inverse variance weighted (IVW), complemented by supplementary methods including MR-Egger, weighted median, weighted mode, maximum likelihood, MR-PRESSO, and cML-MA. Reverse MR analysis was performed on the bacteria that were found to be causally associated with PsA in forward MR analysis. Cochran’s IVW Q statistic was utilized to assess the heterogeneity of instrumental variables among the selected single nucleotide polymorphisms.ResultsIVW estimates revealed that Ruminococcaceae_UCG-002 (odds ratio (OR) = 0.792, 95% confidence interval (CI), 0.643–0.977, p = 0.029) exhibited a protective effect on PsA. Conversely, Blautia (OR = 1.362, 95% CI, 1.008–1.842, p = 0.044), Eubacterium_fissicatena_group (OR = 1.28, 95% CI, 1.075–1.524, p = 0.006), and Methanobrevibacter (OR = 1.31, 95% CI, 1.059–1.621, p = 0.013) showed a positive correlation with the risk of PsA. No significant heterogeneity, horizontal pleiotropy, or outliers were observed, and the results of the MR analysis remained unaffected by any single nucleotide polymorphisms. According to the results of reverse MR analysis, no significant causal effect of PsA was found on gut microbiome.ConclusionThis study establishes for the first time a causal relationship between the gut microbiome and PsA, providing potential valuable strategies for the prevention and treatment of PsA. Further randomized controlled trials are urgently warranted to support the targeted protective mechanisms of probiotics on PsA

Inhibition of Nur77 expression and translocation by compound B6 reduces ER stress and alleviates cigarette smoke-induced inflammation and injury in bronchial epithelial cells

Chronic obstructive pulmonary disease (COPD) is a leading cause of death worldwide with inflammation and injury in airway epithelial cells. However, few treatment options effectively reduce severity. We previously found that Nur77 is involved in lipopolysaccharide-induced inflammation and injury of lung tissue. Here, we established an in vitro model of COPD-related inflammation and injury in 16-HBE cells induced by cigarette smoke extract (CSE). In these cells, Nur77 expression and localization to the endoplasmic reticulum (ER) increased following CSE treatment, as did ER stress marker (BIP, ATF4, CHOP) expression, inflammatory cytokine expression, and apoptosis. The flavonoid derivative, named B6, which was shown to be a modulator of Nur77 in previous screen, molecular dynamics simulation revealed that B6 binds strongly to Nur77 through hydrogen bonding and hydrophobic interactions. Treating CSE-stimulated 16-HBE cells with B6 resulted in a reduction of both inflammatory cytokine expression and secretion, as well as attenuated apoptosis. Furthermore, B6 treatment resulted in a decrease in Nur77 expression and translocation to the ER, which was accompanied by a concentration-dependent reduction in the expression of ER stress markers. Meanwhile, B6 played a similar role in CSE-treated BEAS-2B cells. These combined effects suggest that B6 could inhibit inflammation and apoptosis in airway epithelial cells after cigarette smoke stimulation, and support its further development as a candidate intervention for treating COPD-related airway inflammation

The First Polarimetric View on Quasi-Periodic Oscillations in a Black Hole X-ray Binary

We present the first polarimetric analysis of Quasi-Periodic Oscillations (QPO) in a black hole binary utilizing \textit{IXPE} data. Our study focuses on Swift J1727.8--1613, which experienced a massive outburst that was observed by various telescopes across different wavelengths. The \textit{IXPE} observation we studied was conducted during the Hard-Intermediate state. The polarization degree (PD) and polarization angle (PA) were measured at 4.28$\pm$0.20\% and $1.9^{\circ}\pm1.4^{\circ}$, respectively. Remarkably, significant QPO signals were detected during this observation, with a QPO frequency of approximately 1.34 Hz and a fractional root-mean-square (RMS) amplitude of about 12.3\%. Furthermore, we conducted a phase-resolved analysis of the QPO using the Hilbert-Huang transform technique. The photon index showed a strong modulation with respect to the QPO phase. In contrast, the PD and PA exhibit no modulations in relation to the QPO phase, which is inconsistent with the expectation of the Lense-Thirring precession of the inner flow. Further theoretical studies are needed to conform with the observational results.Comment: Accepted for publication in APJ

Biological and genomic analysis of a symbiotic nitrogen fixation defective mutant in Medicago truncatula

Medicago truncatula has been selected as one of the model legume species for gene functional studies. To elucidate the functions of the very large number of genes present in plant genomes, genetic mutant resources are very useful and necessary tools. Fast Neutron (FN) mutagenesis is effective in inducing deletion mutations in genomes of diverse species. Through this method, we have generated a large mutant resource in M. truncatula. This mutant resources have been used to screen for different mutant using a forward genetics methods. We have isolated and identified a large amount of symbiotic nitrogen fixation (SNF) deficiency mutants. Here, we describe the detail procedures that are being used to characterize symbiotic mutants in M. truncatula. In recent years, whole genome sequencing has been used to speed up and scale up the deletion identification in the mutant. Using this method, we have successfully isolated a SNF defective mutant FN007 and identified that it has a large segment deletion on chromosome 3. The causal deletion in the mutant was confirmed by tail PCR amplication and sequencing. Our results illustrate the utility of whole genome sequencing analysis in the characterization of FN induced deletion mutants for gene discovery and functional studies in the M. truncatula. It is expected to improve our understanding of molecular mechanisms underlying symbiotic nitrogen fixation in legume plants to a great extent

Robust estimation of bacterial cell count from optical density

Optical density (OD) is widely used to estimate the density of cells in liquid culture, but cannot be compared between instruments without a standardized calibration protocol and is challenging to relate to actual cell count. We address this with an interlaboratory study comparing three simple, low-cost, and highly accessible OD calibration protocols across 244 laboratories, applied to eight strains of constitutive GFP-expressing E. coli. Based on our results, we recommend calibrating OD to estimated cell count using serial dilution of silica microspheres, which produces highly precise calibration (95.5% of residuals <1.2-fold), is easily assessed for quality control, also assesses instrument effective linear range, and can be combined with fluorescence calibration to obtain units of Molecules of Equivalent Fluorescein (MEFL) per cell, allowing direct comparison and data fusion with flow cytometry measurements: in our study, fluorescence per cell measurements showed only a 1.07-fold mean difference between plate reader and flow cytometry data

Non-Blind Image Deblurring via Shear Total Variation Norm

In this paper, we propose a novel shear gradient operator by combining the shear and gradient operators. The shear gradient operator performs well to capture diverse directional information in the image gradient domain. Based on the shear gradient operator, we extend the total variation (TV) norm to the shear total variation (STV) norm by adding two shear gradient terms. Subsequently, we introduce a shear total variation deblurring model. Experimental results are provided to validate the ability of the STV norm to capture the detailed information. Leveraging the Block Circulant with Circulant Blocks (BCCB) structure of the shear gradient matrices, the alternating direction method of multipliers (ADMM) algorithm can be used to solve the proposed model efficiently. Numerous experiments are presented to verify the performance of our algorithm for non-blind image deblurring

Experimental Analysis and Full Prediction Model of a 5-DOF Motorized Spindle

The cost and power consumption of DC power amplifiers are much greater than that of AC power converters. Compared to a motorized spindle supported with DC magnetic bearings, a motorized spindle supported with AC magnetic bearings is inexpensive and more efficient. This paper studies a five-degrees-of-freedom (5-DOF) motorized spindle supported with AC hybrid magnetic bearings (HMBs). Most models of suspension forces, except a “switching model”, are quite accurate, but only in a particular operating area and not in regional coverage. If a “switching model” is applied to a 5-DOF motorized spindle, the real-time performance of the control system can be significantly decreased due to the large amount of data processing for both displacement and current. In order to solve this defect, experiments based on the “switching model” are performed, and the resulting data are analyzed. Using the data analysis results, a “full prediction model” based on the operating state is proposed to improve real-time performance and precision. Finally, comparative, verification and stiffness tests are conducted to verify the improvement of the proposed model. Results of the tests indicate that the rotor has excellent characteristics, such as good real-time performance, superior anti-interference performance with load and the accuracy of the model in full zone. The satisfactory experimental results demonstrate the effectiveness of the “full prediction model” applied to the control system under different operating stages. Therefore, the results of the experimental analysis and the proposed full prediction model can provide a control system of a 5-DOF motorized spindle with the most suitable mathematical models of the suspension force

Improvement of Temperature Performance of Singlemode-Multimode-Singlemode Fiber Structure

A theoretical model for studying the temperature properties of singlemode-multimode-singlemode (SMS) fiber structure fabricated by absorptive multimode fiber (MMF) cladding is established. Moreover, an SMS-based temperature sensor is fabricated and experimentally demonstrated. Experimental results show that the dip wavelength of the transmission spectrum changes linearly with temperature, which is in good agreement with the simulated results obtained by using the model. Further, a comprehensive study of temperature characteristics affected by the thermo-optic effect, thermal expansion effect, and thermal effect of absorption characteristics is performed for SMS fiber optic structures with different refractive indexes, thermo-optic coefficients, and absorption properties of MMF cladding, MMF core diameters, and thermal expansion coefficients of packaging shell. According to the obtained rules, investigations are carried out into the thermal response of an SMS fiber structure resulting from combined thermal effects for temperature performance optimization. Excellent temperature stability with a temperature sensitivity of 0 pm/°C or good temperature sensitivity of −441.58 pm/°C is achieved accordingly