Latest Articles

Open AccessFeature PaperArticle
Online MTPA Trajectory Tracking of IPMSM Based on a Novel Torque Control Strategy
Energies 2019, 12(17), 3261; https://doi.org/10.3390/en12173261 (registering DOI) -
Abstract
The maximum-torque-per-ampere (MTPA) scheme is widely used in the interior permanent magnet synchronous machine (IPMSM) drive system to reduce copper losses. However, MTPA trajectory is complicated to solve analytically. In order to realize online MTPA trajectory tracking, this paper proposes a novel torque [...] Read more.
The maximum-torque-per-ampere (MTPA) scheme is widely used in the interior permanent magnet synchronous machine (IPMSM) drive system to reduce copper losses. However, MTPA trajectory is complicated to solve analytically. In order to realize online MTPA trajectory tracking, this paper proposes a novel torque control strategy. The torque control is designed to be closed form. Considering the machine reluctance torque as the torque feedback, when this is compared with the torque reference, then the excitation torque reference can be obtained. Since the excitation torque is proportional to the q-axis current, the q-axis current reference can be fed by the excitation torque reference through a proportional regulator. Once the q-axis current reference is given, the d-axis current reference can be calculated based on the per-unit model, which aims to simplify the calculation and make the control strategy independent of machine parameters. In this paper, the stability of the control system is demonstrated. Meanwhile, simulation and experiment results show this torque control strategy can realize MTPA trajectory tracking online and have success in transients. Full article
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Open AccessReview
Immune-Escape Hepatitis B Virus Mutations Associated with Viral Reactivation upon Immunosuppression
Viruses 2019, 11(9), 778; https://doi.org/10.3390/v11090778 (registering DOI) -
Abstract
Hepatitis B virus (HBV) reactivation occurs as a major complication of immunosuppressive therapy among persons who have recovered from acute hepatitis and those who have controlled chronic infection. Recent literature data emphasize the presence of a high degree of S gene variability in [...] Read more.
Hepatitis B virus (HBV) reactivation occurs as a major complication of immunosuppressive therapy among persons who have recovered from acute hepatitis and those who have controlled chronic infection. Recent literature data emphasize the presence of a high degree of S gene variability in HBV isolates from patients who developed reactivation. In reactivated HBV, the most frequently detected mutations belong to the second loop of “a” determinant in HBsAg. These mutations were identified to be immune escape and responsible for vaccine- and diagnostic-escape phenomena. Their emergence clearly provides survival in the presence of a developed humoral immune response and is often associated with impaired serological diagnosis of HBV reactivation. The knowledge of their existence and roles can elucidate the process of reactivation and strongly highlights the importance of HBV DNA detection in monitoring all patients with a history of HBV infection who are undergoing immunosuppression. This review discusses the possible influence of the most frequently found immune-escape mutations on HBV reactivation. Full article
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Open AccessArticle
Aggregation States of Aβ1–40, Aβ1–42 and Aβp3–42 Amyloid Beta Peptides: A SANS Study
Int. J. Mol. Sci. 2019, 20(17), 4126; https://doi.org/10.3390/ijms20174126 (registering DOI) -
Abstract
Aggregation states of amyloid beta peptides for amyloid beta Aβ140 to Aβ142 and Aβp342 are investigated through small angle neutron scattering (SANS). The knowledge of these small peptides and their [...] Read more.
Aggregation states of amyloid beta peptides for amyloid beta Aβ140 to Aβ142 and Aβp342 are investigated through small angle neutron scattering (SANS). The knowledge of these small peptides and their aggregation state are of key importance for the comprehension of neurodegenerative diseases (e.g., Alzheimer’s disease). The SANS technique allows to study the size and fractal nature of the monomers, oligomers and fibrils of the three different peptides. Results show that all the investigated peptides have monomers with a radius of gyration of the order of 10 Å, while the oligomers and fibrils display differences in size and aggregation ability, with Aβp342 showing larger oligomers. These properties are strictly related to the toxicity of the corresponding amyloid peptide and indeed to the development of the associated disease. Full article
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Open AccessArticle
A Transcriptional Activator of Ascorbic Acid Transport in Streptococcus pneumoniae Is Required for Optimal Growth in Endophthalmitis in a Strain-Dependent Manner
Microorganisms 2019, 7(9), 290; https://doi.org/10.3390/microorganisms7090290 (registering DOI) -
Abstract
Streptococcus pneumoniae is among the top causes of bacterial endophthalmitis, an infectious disease of the intraocular fluids. The mechanisms by which S. pneumoniae grows and thrives in the intraocular cavity are not well understood. We used a bacterial genome-wide assessment tool (transposon insertion [...] Read more.
Streptococcus pneumoniae is among the top causes of bacterial endophthalmitis, an infectious disease of the intraocular fluids. The mechanisms by which S. pneumoniae grows and thrives in the intraocular cavity are not well understood. We used a bacterial genome-wide assessment tool (transposon insertion site sequencing) to determine genes essential for S. pneumoniae growth in vitreous humor. The results indicated that an ascorbic acid (AA) transport system subunit was important for growth. We created an isogenic gene deletion mutant of the AA transcriptional activator, ulaR2, in 2 strains of S. pneumoniae. Growth curve analysis indicated that ulaR2 deletion caused attenuated growth in vitro for both strains. However, in vivo vitreous humor infection in rabbits with either strain determined that ulaR2 was necessary for growth in one strain but not the other. These results demonstrate that ulaR2 may be important for fitness during S. pneumoniae endophthalmitis depending on the background of the strain. Full article
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Open AccessCase Report
Drinking Water Risk Management Plan: A Case Study in the Ore Processing Industry
Safety 2019, 5(3), 58; https://doi.org/10.3390/safety5030058 (registering DOI) -
Abstract
All of the water supply system development needs to be safe and meet health requirements. Due to the expansion of the ore processing industry, water supply providers are required to identify the risks that may arise from dangerous and hazardous events. The purpose [...] Read more.
All of the water supply system development needs to be safe and meet health requirements. Due to the expansion of the ore processing industry, water supply providers are required to identify the risks that may arise from dangerous and hazardous events. The purpose of this study was to build a structured approach to drinking water risk management plans (RMPs). We used risk assessments with reference to the environmental management system, risk management, and the food safety management system. The results of the risk assessment show two critical control points (CCPs) of high risk: Dam (catchment) and pipe reticulation. Some CCPs were categorized as posing very high risks of hazardous events due to pathogen contamination, including the clean water tank, the disinfectant injector, and pipe reticulation. The RMPs recorded and identified various preventive measures that could be taken to reduce and eliminate the risks. Daily operational requirements can be implemented to prepare for these hazards and risks that have the potential to negatively affect the quality of the drinking water supplied to the workers. Risk assessments were conducted in two stages: Preventive measures and operational monitoring. The involvement of all departments and authority agencies was crucial to ensure the success in the development and review of the operational aspects of these RMPs. Full article
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Open AccessArticle
Discrete Element Method (DEM) and Experimental Studies of the Angle of Repose and Porosity Distribution of Pellet Pile
Processes 2019, 7(9), 561; https://doi.org/10.3390/pr7090561 (registering DOI) -
Abstract
The lumpy zone in a blast furnace is composed of piles formed naturally during burden charging. The properties of this zone have significant effects on the blast furnace operation, including heat and mass transfer, chemical reactions and gas flow. The properties of the [...] Read more.
The lumpy zone in a blast furnace is composed of piles formed naturally during burden charging. The properties of this zone have significant effects on the blast furnace operation, including heat and mass transfer, chemical reactions and gas flow. The properties of the layers mainly include the angle of repose and porosity distribution. This paper introduces two methods, the Discharging Method and the Lifting Method, to study the influence of the packing method on the angle of repose of the pile. The relationships of the angle of repose and porosity with physical parameters are also investigated. The porosity distribution in the bottom of a pile shows a decreasing trend from the region below the apex to the center. The coordination number of the particles is employed to explain this change. The maximum of the frequency distribution of it was found to show a negative correlation to the static friction coefficient, but becomes insensitive to the parameter as the static friction coefficient increases above 0.6. Full article
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Open AccessFeature PaperArticle
Ground State Solution of Pohožaev Type for Quasilinear Schrödinger Equation Involving Critical Exponent in Orlicz Space
Mathematics 2019, 7(9), 779; https://doi.org/10.3390/math7090779 (registering DOI) -
Abstract
We study the following quasilinear Schrödinger equation involving critical exponent -Δu+V(x)u-Δ(u2)u=A(x)|u|p-1u+λB(x [...] Read more.
We study the following quasilinear Schrödinger equation involving critical exponent -Δu+V(x)u-Δ(u2)u=A(x)|u|p-1u+λB(x)u3N+2N-2, u(x)>0 for xRN and u(x)0 as |x|. By using a monotonicity trick and global compactness lemma, we prove the existence of positive ground state solutions of Pohožaev type. The nonlinear term |u|p-1u for the well-studied case p[3,3N+2N-2), and the less-studied case p[2,3), and for the latter case few existence results are available in the literature. Our results generalize partial previous works. Full article
Open AccessArticle
A New Class of Iterative Processes for Solving Nonlinear Systems by Using One Divided Differences Operator
Mathematics 2019, 7(9), 776; https://doi.org/10.3390/math7090776 (registering DOI) -
Abstract
In this manuscript, a new family of Jacobian-free iterative methods for solving nonlinear systems is presented. The fourth-order convergence for all the elements of the class is established, proving, in addition, that one element of this family has order five. The proposed methods [...] Read more.
In this manuscript, a new family of Jacobian-free iterative methods for solving nonlinear systems is presented. The fourth-order convergence for all the elements of the class is established, proving, in addition, that one element of this family has order five. The proposed methods have four steps and, in all of them, the same divided difference operator appears. Numerical problems, including systems of academic interest and the system resulting from the discretization of the boundary problem described by Fisher’s equation, are shown to compare the performance of the proposed schemes with other known ones. The numerical tests are in concordance with the theoretical results. Full article
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Open AccessReview
Creatine for the Treatment of Depression
Biomolecules 2019, 9(9), 406; https://doi.org/10.3390/biom9090406 (registering DOI) -
Abstract
Depressed mood, which can occur in the context of major depressive disorder, bipolar disorder, and other conditions, represents a serious threat to public health and wellness. Conventional treatments are not effective for a significant proportion of patients and interventions that are often beneficial [...] Read more.
Depressed mood, which can occur in the context of major depressive disorder, bipolar disorder, and other conditions, represents a serious threat to public health and wellness. Conventional treatments are not effective for a significant proportion of patients and interventions that are often beneficial for treatment-refractory depression are not widely available. There is, therefore, an immense need to identify novel antidepressant strategies, particularly strategies that target physiological pathways that are distinct from those addressed by conventional treatments. There is growing evidence from human neuroimaging, genetics, epidemiology, and animal studies that disruptions in brain energy production, storage, and utilization are implicated in the development and maintenance of depression. Creatine, a widely available nutritional supplement, has the potential to improve these disruptions in some patients, and early clinical trials indicate that it may have efficacy as an antidepressant agent. Full article
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Open AccessArticle
WOF-SWAT: A Web-Based Open-Source Framework for Investigating the Hydrological Impacts of Climate Change and Human Activities Through Online Simulation and Visualization of SWAT Models
ISPRS Int. J. Geo-Inf. 2019, 8(9), 368; https://doi.org/10.3390/ijgi8090368 (registering DOI) -
Abstract
This study developed a web-based open-source framework based on the Soil and Water Assessment Tool (SWAT), named WOF-SWAT (web-based open-source framework for SWAT), to investigate individual and combined impacts of climate change, land use change, and point-source pollutants on watershed-scale hydrological and chemical [...] Read more.
This study developed a web-based open-source framework based on the Soil and Water Assessment Tool (SWAT), named WOF-SWAT (web-based open-source framework for SWAT), to investigate individual and combined impacts of climate change, land use change, and point-source pollutants on watershed-scale hydrological and chemical processes. The architecture, workflows, interfaces, and key processes of WOF-SWAT are described and discussed. Using a previously developed well-calibrated hydrological model of the Jinjiang River basin, four scenarios were simulated in WOF-SWAT and other traditional desktop-based tools (i.e., ArcSWAT and SWAT-CUP) to examine the credibility, efficiency, and functionality of WOF-SWAT. The results show that, in combination with a well-calibrated watershed model, WOF-SWAT is sufficiently sound and reasonable to investigate individual and combined impacts of climate change, land use change, and point-source pollutants. We thus conclude that WOF-SWAT can be used as a substitute for other tools to carry out similar tasks in a web-based environment while providing more user-friendly interfaces, accessibility, and efficiency. We also discuss ongoing and possible future efforts to develop WOF-SWAT into a fully-fledged watershed research and management framework. Full article
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Open AccessArticle
Antibacterial Effect of Carbosilane Metallodendrimers in Planktonic Cells of Gram-Positive and Gram-Negative Bacteria and Staphylococcus aureus Biofilm
Biomolecules 2019, 9(9), 405; https://doi.org/10.3390/biom9090405 (registering DOI) -
Abstract
Antibiotic resistance is currently one of the main threats to public health security. Biofilm formation is a resistance mechanism that is responsible for most human bacterial infections and requires new and effective therapeutic approaches, such as those provided by nanotechnology. In this work, [...] Read more.
Antibiotic resistance is currently one of the main threats to public health security. Biofilm formation is a resistance mechanism that is responsible for most human bacterial infections and requires new and effective therapeutic approaches, such as those provided by nanotechnology. In this work, the antibacterial effect of carbosilane metallodendrimers with different metals (copper(II) and ruthenium(II)), ligands (chloride and nitrate) and generations (generation 0, 1 and 2) has been studied using planktonic Gram-positive (Staphylococcus aureus) and Gram-negative (Escherichia coli) bacteria. Furthermore, the ability of the metallodendrimers to avoid the formation of S. aureus biofilms was also evaluated. The results showed a promising biocide activity in both types of planktonic bacteria, especially for first-generation dendrimers, which arises from the metal complexation to the dendrimer. Cu(II) metallodendrimers require lower concentration than Ru(II) counterpart to inhibit the production of S. aureus biofilms, but none produce hemolysis at the inhibitory concentrations and can be safely used as antibacterial agents. In particular, the first-generation Cu(II) metallodendrimer with nitrate ligands displayed the most promising properties to continue with further studies in both planktonic cells and biofilms. Full article
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Open AccessArticle
Interaction of Methane Concentration and Deposition Temperature in Atmospheric Laser Based CVD Diamond Deposition on Hard Metal
Coatings 2019, 9(9), 537; https://doi.org/10.3390/coatings9090537 (registering DOI) -
Abstract
For laser-based plasma chemical vapour deposition (CVD) of diamond on hard metal at atmospheric pressure, without a vacuum chamber, the interaction between the deposition temperature and the methane concentration has to be understood to adjust the coating thickness, deposition duration, and medium diamond [...] Read more.
For laser-based plasma chemical vapour deposition (CVD) of diamond on hard metal at atmospheric pressure, without a vacuum chamber, the interaction between the deposition temperature and the methane concentration has to be understood to adjust the coating thickness, deposition duration, and medium diamond crystal size. The hypothesis of this study is that a wider range of methane concentrations could be used to deposit microcrystalline diamond coatings due to the increasing etching and deposition rates with rising deposition temperatures. The deposition of the CVD diamond coatings was carried out on K10 hard metal substrates. The process temperature and the methane concentration were varied from 650 to 1100 °C and from 0.15% to 5.0%, respectively. The coatings were analysed by scanning electron and 3D laser-scanning confocal microscopy, energy dispersive X-ray and micro-Raman spectroscopy, as well as cryofracture-based microscopy analysis. The results showed that microcrystalline diamond coatings could be deposited in a wider range of methane concentrations when increasing the process temperature. The coating thickness saturates depending on the process temperature even though the methane concentration constantly increases. The coating thickness increases with an increasing deposition temperature until the cobalt diffusion hinders the deposition at the process temperature of 1100 °C. Full article
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Open AccessArticle
SEPT14 Mutations and Teratozoospermia: Genetic Effects on Sperm Head Morphology and DNA Integrity
J. Clin. Med. 2019, 8(9), 1297; https://doi.org/10.3390/jcm8091297 (registering DOI) -
Abstract
The main objective of this study was to evaluate the potential genetic effects of SEPT14 on male infertility through sequencing the SEPT14 coding region. To address this research gap, 254 men with sperm abnormalities and 116 normozoospermic men were recruited, and the whole-coding [...] Read more.
The main objective of this study was to evaluate the potential genetic effects of SEPT14 on male infertility through sequencing the SEPT14 coding region. To address this research gap, 254 men with sperm abnormalities and 116 normozoospermic men were recruited, and the whole-coding regions of SEPT14 were sequenced. Two heterozygous mutations, p.Ala123Thr (3/254 vs. 0/116) and p.Ile333Thr (3/254 vs. 0/116), were identified in these cases. A high percentage of defective sperm heads was found in sperm with mutated SEPT14. Both mutations are highly evolutionarily conserved among vertebrates. The results of a fine morphological and chromatin structural analysis indicated severely malformed sperm heads with abnormal chromatin packaging through transmission electron microscopy and Toluidine blue staining. Compared with controls, high DNA fragmentation was demonstrated in sperm from cases carrying SEPT14 mutations using the comet assay. In addition, these two mutations in SEPT14 affected its polymerization ability in vitro. These data revels that the two SEPT14 missense mutations impaired sperm head morphology and induced DNA damage. Our study suggests that genetic variant of SEPT14 is one of the effects for human sperm formation and male fertility. Full article
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