Original Reference Research Articles

Thoracic Vertebral Length-to-Height Ratio, a Promising Parameter to Predict the Vertebral Heart Score in Normal Welsh Corgi Pembroke Dogs

The vertebral heart score (VHS) is the sum of the ratio of the cardiac dimensions to the number of thoracic vertebrae, starting from the fourth thoracic vertebra (T4) to the intervertebral disk space (IVS). Breed-specific VHSs, in most cases, were different from the original reference value. Characteristics of the thoracic vertebrae and IVS may influence this variation. This study was conducted to investigate the characteristics of the T4 and IVS on the thoracic radiographs of Corgis in comparison with other small-to-medium breed dogs to evaluate the Corgi-specific VHSs in healthy dogs. The ratio of the T4's length/height (T4L/H) was significantly different among dog breeds but not the IVS between the T4 and T5. The T4L/H was highest in the Shih Tzu and lowest in Beagle dogs. The Corgi-specific VHS obtained from the ventrodorsal radiograph was significantly higher than that from the dorsoventral radiograph, but a significant difference was not observed between the right and left lateral radiographs. In contrast, the Corgi-specific VHS derived from the right lateral thoracic radiograph was significantly lower than the reference value. This may be correlated with the characteristics of the thoracic vertebrae of Corgis, which were slightly higher than those of the other breeds.

Increased fT4 concentrations in patients using levothyroxine without complete suppression of TSH.

In our hospital, physicians noticed high free thyroxine (fT4) concentrations without complete suppression of thyroid-stimulating hormone (TSH) in blood samples of patients at the outpatient clinic, which appeared to occur more often following the introduction of a new fT4 immunoassay. This discordance may be explained by incorrect reference intervals, analytical issues, or patient-related factors. We aimed to establish the contribution of the possible factors involved. Reference intervals of both fT4 immunoassays were re-evaluated using blood samples of healthy volunteers and the new immunoassay's performance was assessed using internal quality controls and external quality rounds. The frequency of discordant fT4 and TSH pairings obtained from laboratory requests were retrospectively analysed using a Delfia (n = 3174) and Cobas cohort (n = 3408). Last, a literature search assessed whether the time of blood draw and the time of levothyroxine (L-T4) ingestion may contribute to higher fT4 concentrations in L-T4 users. The original reference intervals of both fT4 immunoassays were confirmed and no evidence for analytical problems was found. The Delfia (n = 176, 5.5%) and Cobas cohorts (n = 295, 8.7%) showed comparable frequencies of discordance. Interestingly, 72-81% of the discordant results belonged to L-T4 users. Literature indicated the time of blood withdrawal of L-T4 users and, therefore, the time of L-T4 intake as possible explanations. High fT4 without suppressed TSH concentrations can mainly be explained by L-T4 intake. Physicians and laboratory specialists should be aware of this phenomenon to avoid questioning the assay's performance or unnecessarily adapting the L-T4 dose in patients.

Genetic diversity among reptilian orthoreoviruses isolated from pet snakes and lizards.

Reovirus infections in reptiles are frequently detected and associated with various clinical diseases; yet, our knowledge about their genetic diversity and evolutionary relationships remains limited. In this study, we characterize at the genomic level five reptile origin orthoreovirus strains isolated from exotic snakes and lizards in Hungary and Germany. The genomic organization of the study strains was similar to that of the representative strains of reptile origin reoviruses belonging to species Reptilian orthoreovirus and Testudine orthoreovirus. Additionally, all five study strains clustered with the bush viper origin reference Reptilian orthoreovirus strain, 47/02. The nucleotide sequence divergence among strains fell from 56.64 to 99.36%. Based on genome segment constellations two well separated groups were observed, which may represent two genetic lineages of reptilian orthoreoviruses we tentatively referred here as genogroups, classifying two squamata origin strains with available whole genome sequences into genogroup I (GGI) and four strains into genogroup II (GGII). The representative GGI and GGII Reptilian orthoreovirus strains are characterized by moderate-to-high nucleotide and amino acid similarities within genogroups (range, 69.45 to 99.36% and 74.64 to 100.00%), whereas lower nucleotide and amino acid similarities (range, 56.64 to 77.24% and 54.53 to 93.85%) and different structures of the bicistronic S1 segment were found between genogroups. Further studies are needed to explore the genomic diversity among reptilian reoviruses of squamata origin; this would be critical to establish a robust classification system for these viruses and to see if interaction among members of distinct lineages may result in viable progenies with novel genetic features.

No-Reference Image Quality Assessment via Multibranch Convolutional Neural Networks

No-reference image quality assessment (NR-IQA) aims to evaluate image quality without using the original reference images. Since the early NR-IQA methods based on distortion types were only applicable to specific distortion scenarios, and lack of practicality, it is challenging to designing a universal NR-IQA method. In this article, a multibranch convolutional neural network (MB-CNN) based NR-IQA method is proposed, which includes a spatial-domain feature extractor, a gradient-domain feature extractor, and a weight mechanism. The spatial-domain feature extractor aims to extract the distortion features from the spatial domain. The gradient-domain feature extractor is used to guide the spatial-domain feature extractor to pay more attention to the distortions of the structure information. Particularly, the spatial-domain feature extractor uses the hierarchical feature merge module to realize multiscale feature representation, and the gradient-domain feature extractor uses pyramidal convolution to extract the multiscale structure information of the distorted image. In addition, a position vector is proposed to build the weight mechanism by considering the position relationships between patches and its entire image for improving the final prediction performance. We conduct the experiments on five representative databases: LIVE, TID2013, CSIQ, LIVE MD and Waterloo Exploration Database, and the experimental results show that the proposed NR-IQA method achieves the state-of-the-art performance, which demonstrate the effectiveness of our proposed NR-IQA method. The code ofthe proposed MB-CNN will be released at <uri xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">https://github.com/NUIST-Videocoding/MB-CNN</uri> .

GlucoKinaseDB: A comprehensive, curated resource of glucokinase modulators for clinical and molecular research

Glucokinase (GK), an isoform of hexokinase expressed predominantly in liver, pancreas and hypothalamus is crucial to blood glucose management. It is a critical component of the glucose-sensing mechanism of the pancreatic islet cells and glycogen regulation in hepatocytes. GK modulators such as allosteric GKAs (glucokinase activators) and GK-GKRP (glucokinase regulatory protein) disruptors have found potential applications as safer antihyperglycemics. Recent studies have also demonstrated the potential of GK modulators as antiparasitic agents. Researchers targeting GK often undertake the time-consuming task of independently collecting and compiling modulator information due to the lack of any dedicated single-platform resource. Towards this, in the present study we demonstrate the design and development of GlucoKinaseDB (GKDB), a comprehensive, curated, online resource of GK modulators. GKDB contains experimentally derived structural and bioactivity information of 1723 modulators along with their detailed molecular descriptors. The web-interface is user-friendly with features such as in-browser visualization, advanced search queries, cross-links to other databases and original reference etc. The bioactivity and descriptor data can be downloaded in bulk (for entire database) or for individual modulators. The 3D structures are also downloadable in multiple formats. GKDB employs a PHP-based web design with Bootstrap styling and a MySQL database backend. GKDB can be utilized for clinical and molecular research via development of pharmacophore hypotheses, QSAR/QSPR models, predictive machine learning models etc. GKDB is freely accessible online at https://glucokinasedb.in.

Auditoría jurídica empresarial en la fiscalización en la república de Ecuador

This work, drawing from the original reference of Compliance Programmes from the theoretical doctrinal analysis of comparative law, allows us to propose a corporate legal audit for public companies in Ecuador. The development of this study aims to traverse foreign doctrine, legislation, and jurisprudence in terms of the commission of crimes resulting from mercantile business, which are escalating due to the dynamics of globalization and the internet. In relation to this, reference is made to global transformations and the emergence of new criminal behaviors, as well as a rigid and outdated punitive power of the Ecuadorian state in the face of new phenomena. Utilizing techniques such as questionnaires, document analysis, and interviews, criminal acts within corporations are examined, always seeking their resolution and eradication.

Innovación curricular emergente ante el Covid-19: propuestas para la educación universitaria

This work, drawing from the original reference of Compliance Programmes from the theoretical doctrinal analysis of comparative law, allows us to propose a corporate legal audit for public companies in Ecuador. The development of this study aims to traverse foreign doctrine, legislation, and jurisprudence in terms of the commission of crimes resulting from mercantile business, which are escalating due to the dynamics of globalization and the internet. In relation to this, reference is made to global transformations and the emergence of new criminal behaviors, as well as a rigid and outdated punitive power of the Ecuadorian state in the face of new phenomena. Utilizing techniques such as questionnaires, document analysis, and interviews, criminal acts within corporations are examined, always seeking their resolution and eradication.

The Efficacy and Safety of Acupuncture in Treating Stress Urinary Incontinence in Women from a Meta-Analysis of Four Randomized Controlled Trials.

To verify the efficacy and safety of acupuncture in treating stress urinary incontinence (SUI) in women in a single treatment cycle lasting at least 6 weeks. A preferred reporting items for systematic reviews and meta-analyses (PRISMA) summary was followed correctly. Through the use of EMBASE, Cochrane Library databases, and PubMed (until July 2021), we looked for randomized controlled trials. In addition, the included articles' original references were looked up as well. Totally, we analyzed four studies including 690 patients. Compared with the sham acupuncture group, this analysis verified that acupuncture was critically better result in decreasing mean urine leakage (p = 0.04), 1-hour pad test (p = 0.04), 72-hour incontinence episodes (p < 0.00001), International Consultation on Incontinence Questionnaire-Short Form scores (p = 0.0005) and improving patient self-evaluation (All p < 0.05). However, two groups had no statistical significance in improving pelvic floor muscle strength. In the matter of safety, mainly adverse events, especially with respect to pain, both groups showed no statistical difference. Acupuncture is more beneficial to patients with stress urinary incontinence in women with no critical difference in the incidence of advent events than sham acupuncture.

An ultrastructural and genomic study on the SARS-CoV-2 variant B.1.210 circulating during the first wave of COVID-19 pandemic in India

PurposeThe study aims to isolate and understand cytopathogenesis, ultrastructure, genomic characteristics and phylogenetic analysis of SARS-CoV-2 virus of B.1.210 lineage, that circulated in India during first wave of the pandemic. MethodsClinical specimen from an interstate traveller from Maharashtra to Karnataka, in May 2020, who was positive by RT PCR for SARS-CoV-2 infection was subjected to virus isolation and Whole Genome Sequencing. Vero cells were used to study cytopathogenesis and ultrastructural features by Transmission Electron Microscopy (TEM). Phylogenetic analysis of the whole genome sequences of several SARS-CoV-2 variants downloaded from GISAID was performed in comparison with the B.1.210 variant identified in this study. ResultsThe virus was isolated in Vero cells and identified by immunofluorescence assay and RT PCR. The growth kinetics in infected Vero cells revealed a peak viral titre at 24 ​h post-infection. Ultrastructural studies revealed distinct morphological changes with accumulation of membrane-bound vesicles containing pleomorphic virions in the cytoplasm, with single or multiple intranuclear filamentous inclusions and dilated rough endoplasmic reticulum with viral particles. Whole genome sequence of the clinical specimen as well as the isolated virus revealed the virus to be of lineage B.1.210 with the D614G mutation in the spike protein. Phylogenetic analysis of the whole genome sequence in comparison with other variants reported globally revealed that the isolated SARS-CoV-2 virus of lineage B.1.210 is closely related to the original Wuhan virus reference sequence. ConclusionsThe SARS-CoV-2 variant B.1.210 virus isolated here showed ultrastructural features and cytopathogenesis similar to that of the virus reported during early phase of pandemic. Phylogenetic analysis showed that the isolated virus is closely related to the original Wuhan virus, thereby suggesting that the SARS-CoV-2 lineage B.1.210 that was circulating in India during the early phase of pandemic is likely to have evolved from the original Wuhan strain.

Sensitivity of human sweet taste receptor subunits T1R2 and T1R3 to activation by glucose enantiomers.

We have previously shown that l-glucose, the non-caloric enantiomer of d-glucose, activates the human sweet taste receptor T1R2/T1R3 transiently expressed in HEK293T cells. Here, we show that d- and l-glucose can also activate T1R2 and T1R3 expressed without the counterpart monomer. Serine mutation to alanine in residue 147 in the binding site of T1R3 VFT domain, completely abolishes T1R3S147A activation by either l- or d-glucose, while T1R2/T1R3S147A responds in the same way as T1R2 expressed without its counterpart. We further show that the original T1R2 reference sequence (NM_152232.1) is less sensitive by almost an order of magnitude than the reference sequence at the time this study was performed (NM_152232.4). We find that out of the four differing positions, it is the R317G in the VFT domain of T1R2, that is responsible for this effect in vitro. It is significant for both practical assay sensitivity and because glycine is found in this position in ~20% of the world population. While the effects of the mutations and the partial transfections were similar for d and l enantiomers, their dose-response curves remained distinct, with l-glucose reaching an early plateau.

АНАЛИЗ ОТЕЧЕСТВЕННЫХ ИЗОЛЯТОВ ВИРУСА АФРИКАНСКОЙ ЧУМЫ СВИНЕЙ ПО ГЕНЕТИЧЕСКОМУ МАРКЕРУ EP402R

Recently, the problem of convergent evolution of pathogens (viruses, bacteria) and macroorganism has been of great interest. In turn, the study of evolutionary variability, from the point of view of the virocentric model of evolution, can become an additional link in determining the direction of the evolution of life as a whole. Further study of the genetic variability of the ASF virus genes and the determination of the correlation between the properties of the virus, territorial affiliation and duration of persistence will provide a molecular epizootological picture of the spread of the disease in the Russian Federation. The EP402R marker gene encoding the CD2v protein is known to determine the hemadsorbing properties of the ASF virus, is involved in cell adhesion, and is also associated with virulence and modulation of the immune response. In order to detect changes in the marker gene EP402R of the ASF virus, we made a sample of twenty-two isolates isolated in the Russian Federation from 2017 to 2018. DNA of the ASF virus was isolated from all selected isolates and PCR of the EP402R gene of the ASF virus was performed, followed by extraction of the resulting nucleic acids from agarose gel. Sequence alignment was performed using the Bioedit program and the ClustalW algorithm. Sequencing of nucleotide sequences was carried out using specific primers for the EP402R gene fragment of the ASF virus. In the course of our work, it was found that isolates isolated from domestic pigs and wild boars did not contain genetic changes in the EP402R gene. This region of the genome was found to be identical to the original genome-wide reference strain "Georgia 2007/1".

Improved anisotropy of magnetic remanence results from vectorial readings using novel refinement method

SUMMARYAnisotropy of magnetic remanence (AMR) is typically obtained by imparting a remanence through a sequence of reference directions and subsequent measurement of the remanent magnetic moment with a separate device. This gives rise to potential misalignments which can affect the resultant anisotropy tensor. Vectorial measurements from rock magnetometers are favourable to obtain the best estimate of the anisotropy tensor but make the results highly dependent on the exact knowledge of the reference directions. This can be partly overcome by using the projection of the remanence vector on the reference direction instead of using the full vector in the calculation of the best-fitting anisotropy tensor. Since AMR experiments are laborious, it is troublesome to compensate the loss in information with additional measurements. This paper demonstrates an iterative refinement method to recover the original reference directions and therefore to improve the results of AMR experiments by using full vectorial readings. The method works well with a six-axis protocol for misalignment of the reference directions up to 25° and for degrees of anisotropy up to 250 per cent, which covers most experimental and geological cases.

Bioequivalence Evaluation in Healthy Volunteers: New Generic Formulations of Sitagliptin and Sitagliptin-Metformin Fixed-Dose Combination Compared with the Originator Products.

Three studies compared the bioequivalence (BE) of new generic tablet formulations of sitagliptin (100mg; fasting) and the fixed-dose combination (FDC) of sitagliptin/metformin (50/850mg, 50/1000mg; both fed) in healthy volunteers with the same tablet strengths of the reference products Januvia and Janumet. The study design was open-label, single-dose, randomized with two-way crossover periods. Blood sampling was performed for 72/48h in the sitagliptin/FDC studies, respectively. Primary pharmacokinetic (PK) parameters for sitagliptin and metformin were area under the plasma concentration-time curve from time 0 to last timepoint of measurable concentration (AUC0-t) and maximum plasma concentration (Cmax). Test (T) and reference (R) formulations proved bioequivalent if 90% confidence interval (CI) of geometric least-squares mean ratio for AUC0-t and Cmax were within BE acceptance range of 80.00-125.00%. Safety evaluations included vital signs, clinical laboratory tests, and adverse events (AEs). Treated/evaluable volunteers for BE per study were: 30/28 (sitagliptin 100mg), 26/25 (FDC 50/850mg), and 26/24 (FDC 50/1000mg). The 90% CI of the geometric means of T/R ratios for primary PK parameters were within predefined BE limits: CI for AUC0-t and Cmax were 95.83-100.37% and 91.85-109.56% (sitagliptin 100mg); 100.84-103.69% and 93.44-105.10% (FDC 50/850mg), and 101.26-105.20% and 98.71-112.89% (FDC 50/1000mg); respective values for metformin were 94.23-101.89% and 91.66-99.38% (FDC 50/850mg) and 98.45-104.89% and 96.79-105.62% (FDC 50/1000mg). All AEs were nonserious, transient, and mostly mild. Safety evaluations did not reveal any relevant difference between T and R formulations. The new generic tablet formulations of sitagliptin 100mg and the FDCs sitagliptin/metformin 50/850mg and 50/1000mg demonstrated bioequivalence to originator reference products. Therefore, the new products are expected to provide efficacy and tolerability similar to those of the reference products in the treatment of patients with type 2 diabetes (T2D). EudraCT EU Clinical Trials Registry (2014-005437-31); ClinicalTrials.gov Registry (NCT05549570 and NCT05549583, both retrospectively registered on 20 September 2022).

Molecular barcoding of Melissa officinalis L. (badranjboye) in Iran and identification of adulteration in its medicinal services

Medicinal plants are an important source for treatment of diseases in many countries. Today, controlling the quality of the products of medicinal plants is an important task. Customer health may be in danger due to the fraud and misconduct by the sales associates in the sales centers. Melissa officinalis L. (Lamiaceae) is an important medicinal plant used for treatment of several diseases. In Iran, the species of Dracocephalum, Hymencrater, Nepeta and Stachys are mistakenly sold under the name of Badranjboye that have different pharmaceutical properties. For avoiding this mistake, this investigation was performed with the following aims: 1) Checking for the cheating and identifying the Badranjboye in the Iran’s market of medicinal plants, 2) Providing the molecular barcode for the medicinal species of Melissa. For this purpose, Market-sold plant samples (leaves) and original reference plant species were compared by morphology, odor as well as Internal transcribed spacer (ITS) and chloroplast DNA ((psbA–trnH) and (trnL–trnF)) sequences. Various molecular analyses, such as sequencing, determination of genetic distance, and construction of phylogenetic tree were performed. These reports have shown that internal transcribed spacer (ITS) and chloroplast DNA (psbA–trnH) sequences are an efficient molecular marker to produce barcode gap and differentiating Melissa officinalis from other species.

Design, synthesis, in vitro, in silico, and SAR studies of flavone analogs towards anti-dengue activity

Flavone has recently been proved as a promising scaffold for the development of a novel drug against dengue fever, one of the major health threats globally. However, the structure–activity relationship study of flavones on the anti-dengue activity remains mostly limited to the natural-occuring analogs. Herein, 27 flavone analogs were successfully synthesized, of which 5 analogs (5e, 5h, 5o, 5q, and 5r) were novel. In total, 33 analogs bearing a diverse range of substituents were evaluated for their efficacy against DENV2-infected LLC/MK2 cells. The introduction of electron-withdrawing groups on ring B such as Br (5m) or NO2 (5n and 5q) enhanced the activity significantly. In particular, the tri-ester 5d and di-ester 5e exhibited low toxicity against normal cell, and exceptional DENV2 inhibition with the EC50 as low as 70 and 68 nM, respectively, which is over 300-fold more active compared to the original baicalein reference. The viral targets for these potent flavone analogs were predicted to be NS5 MTase and NS5 RdRp, as suggested by the likelihood ratios from the molecular docking study. The great binding interaction energy of 8-bromobaicalein (5f) confirms the anti-dengue activity at atomistic level. The physicochemical property of all the synthetic flavone analogs in this study were predicted to be within the acceptable range. Moreover, the QSAR model showed the strong correlation between the anti-dengue activity and the selected molecular descriptors. This study emphasizes the great potential of flavone as a core structure for further development as a novel anti-dengue agent in the future.

More Human Than Human: The Exile in Blade Runner

More Human Than Human: The Exile in <i>Blade Runner</i>

Effect of Recycling on the Mechanical, Thermal and Rheological Properties of Polypropylene/Carbon Nanotube Composites

In this research the effect of physical recycling on the mechanical, thermal, and rheological properties of polypropylene (PP)/multiwalled carbon nanotube (MWCNT) was investigated. After melt homogenization by extrusion, specimens were injection moulded with 0.1 and 0.5 wt% MWCNT content. The recycling process was simulated by multiple grinding and re-moulding, then we compared the behavior of original and recycled PP/MWCNT composites. Differential scanning calorimetry (DSC) measurements proved that MWCNT had double the effect on the morphology of the PP matrix: on the one hand nucleating effect can be detected because 0.5 wt% MWCNT increased the onset temperature of crystallization by 10 °C, compared to the basic PP material; on the other hand, the crystalline fraction of the recycled composite materials decreased compared to the original PP material with the same MWCNT content. This resulted in a slight decrease in strength and stiffness but an increase in elongation at break. However, compared to the original unreinforced PP reference, even the recycled materials have better properties. The mechanical test results showed that recycled PP/MWCNT 0.5 wt% increased the elastic modulus (~15%) and decreased the tensile strain at yield (~10%). However, in the values of tensile stress at yield, relevant difference was not found. It was also shown by oscillatory rheometry that MWCNT had a significant effect on the rheological properties (storage and loss modulus, complex viscosity) of PP compounds in a wide temperature range (190-230 °C).

A Phase-Disposition PWM-Enabled Model Predictive Control for a Nine-Level Inner-Interleaved Hybrid Multilevel Converter

This article brings forward a phase-disposition pulsewidth modulation-enabled model predictive control (PDPWM-MPC) for a nine-level inner-interleaved hybrid multilevel converter (9L-IHMC). First, three layers of virtual space vector diagrams (VSVDs) are established based on the sign patterns of the original and virtual reference vectors in the abc-frame to achieve the phase-disposition pulsewidth modulation (PD-PWM) in a nonindependent three-phase way. Then, three adjacent virtual vectors in the third-layer VSVD, together with their optimized duty cycles, are applied to guarantee the optimal current tracking. Finally, through the use of the duty-cycle alternation approach, dc-link and floating capacitors voltages are balanced and circulating currents are mitigated as well. The proposed PDPWM-MPC can not only enable the decoupling of the low- and high-frequency stages in the 9L-IHMC but also reduce both output current ripples and computational burden. In addition, it can achieve a constant equivalent switching frequency and address the disproportion of power losses associated with the PD-PWM. Both simulations and experiments on a silicon carbide device-based prototype substantiate the effectiveness of the proposed control strategy.

Biosimilars of anti‐vascular endothelial growth factors for ophthalmic disease – Clinical trial status 2022

AbstractPurpose: Diabetic Macular Œdema (DME) and Age‐related Macular Degeneration (nAMD) are the leading causes of vision loss in developed nations. Anti‐Vascular Endothelial Growth Factor (aVEGF) has revolutionized the treatment of both conditions, but access is limited by costs. Biosimilars of aVEGF can cut costs, but prescriber concerns over the lack of clinical data can slow uptake. This paper reports all biosimilar aVEGF in development for Europe and the USA, and pools the results of clinical confirmatory trials to provide statistically greater reassurance in the similarity of outcomes.Methods: Biosimilars in the clinical development phase were identified from US and EU trial registries.Results: There are 13 biosimilars of ranibizumab and aflibercept in final clinical comparative trial stage of development in Europe and the USA, recruiting 6126 patients. Five studies of intravitreal bevacizumab biosimilars are recruiting 772 patients. Equivalence outcomes are typically based on Best‐Corrected Visual Acuity (BCVA) with 90% confidence limits of −3 to +3 letters between reference and biosimilar medicines. Completed trials to date with 1166 participants analysed together show BCVA outcomes of ≤1 letter between Originator Reference Products and Biosimilars; for serious adverse events the risk ratio is 1.17, with 95% confidence intervals of 0.85–1.63, p = 0.32.Conclusions: Biosimilars of aVEGF are expected soon. There are likely sufficient brands expected to create meaningful price competition. To date, the EU/US regulatory pathway is delivering biosimilars with close equivalence of safety and efficacy outcomes.

Adaptive Linear Predictive Model of an Improved Predictive Control of Permanent Magnet Synchronous Motor Over Different Speed Regions

Model predictive control (MPC) strategy can provide significant benefits for controlling nonlinear systems over classical cascade field-oriented control (FOC). However, the MPC is still in the development stage for a high-performance predictive model. Therefore, the proposed MPC in this article updates the internal linear predictive model at each time step to accurately represent the nonlinear plant of a permanent-magnet synchronous motor (PMSM) plant over different speed regions. In other words, the adaptive discrete linear plant model (ADLPM) is designed to update the current operating conditions of the machine parameters and the equilibrium points of the measured stator currents, speed, and load torque. For the operation in the flux-weakening region, the proposed MPC depends on a performance control algorithm (PCA) to obtain high dynamic performance. In this PCA algorithm, the proposed MPC depends on the modified reference velocity rather than the original reference velocity, which can calculate the required <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">d</i> -axis cur <underline xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">r</u> ent directly. Moreover, the proposed cost function is designed directly in terms of the error values of the velocity and <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">d</i> -axis current, which fits the motor performance based on the further constraint of the maximum magnitude of the drawn stator current provided to control the acceleration of the rotor. Finally, comprehensive simulations and experiments have fully demonstrated that the proposed MPC can reduce the speed drop, and torque ripple in response to those of the FOC and traditional MPC strategies.