MDPI - Publisher of Open Access Journals

Urban Science
Enhancing Urban Resilience: Strategic Management for Cyclonic Events through Socially Constructed Risk Processes
Minerals
X-ray CT Analysis of Scheelite Ore, Kara, Australia
Cells
Magnetically-Induces Muscle Secretome Exhibits Anticancer Potency
Symmetry
Charged Lepton-Flavour Violation

Recent Articles

13 pages, 4221 KiB

Open AccessArticle

Design, Analysis, and Comparison of Electric Vehicle Drive Motor Rotors Using Injection-Molded Carbon-Fiber-Reinforced Plastics

by Huai Cong Liu, Jang Soo Park and Il Hwan An

World Electr. Veh. J. 2024, 15(7), 283; https://doi.org/10.3390/wevj15070283 - 25 Jun 2024

Abstract

Due to their excellent mechanical strength, corrosion resistance, and ease of processing, carbon fiber and carbon-fiber-reinforced plastics are finding wide application in diverse fields, including aerospace, industry, and automobiles. This research explores the feasibility of integrating carbon fiber solutions into the rotors of 85-kilowatt electric vehicle interior permanent magnet synchronous motors. Two novel configurations are proposed: a carbon fiber wire-wound rotor and a carbon fiber injection-molded rotor. A finite element analysis compares the performance of these models against a basic designed rotor, considering factors like no-load back electromotive force, no-load voltage harmonics, cogging torque, load torque, torque ripple, efficiency, and manufacturing cost. Additionally, a comprehensive analysis of system efficiency and energy loss based on hypothetical electric vehicle parameters is presented. Finally, mechanical strength simulations assess the feasibility of the proposed carbon fiber composite rotor designs. Full article

(This article belongs to the Special Issue Design and Control of Electrical Machines in Electric Vehicles, 2nd Edition)

► Show Figures

Figure 1

---

Figure 3

---

Figure 4

---

Figure 5

---

Figure 6

---

Figure 7

---

Figure 8

---

Figure 9

---

Figure 10

---

Figure 11

19 pages, 1237 KiB

Open AccessArticle

Impact of Temperature Variations on Torque Capacity in Shrink-Fit Junctions of Water-Jacketed Permanent Magnet Synchronous Motors (PMSMs)

by David Sebastian Puma-Benavides, Luis Mixquititla-Casbis, Edilberto Antonio Llanes-Cedeño and Juan Carlos Jima-Matailo

World Electr. Veh. J. 2024, 15(7), 282; https://doi.org/10.3390/wevj15070282 - 25 Jun 2024

Abstract

This study investigates the impact of temperature variations on the torque capacity of shrink-fit junctions in water-jacketed permanent magnet synchronous motors. Focusing on both baseline and improved designs; torque capacities were evaluated across a temperature range from −40 °C to 120 °C under different material conditions: Least material condition, nominal, and maximum material condition. The baseline design exhibited torque capacities from 7648 Nm to 9032 Nm at −40 °C, decreasing significantly to 549 Nm to 1533 Nm at 120 °C. The improved design showed enhanced performance, with torque capacities ranging from 8055 Nm to 9247 Nm at −40 °C and from 842 Nm to 1618 Nm at 120 °C. The maximum improvement was observed at 120 °C for least material conditions, with a 55.4% increase, and the minimum improvement at −40 °C for maximum material conditions, with a 2.4% increase. Our findings demonstrate a significant increase in torque capacity by up to 20% under varied thermal conditions. These results underscore the effectiveness of design modifications in enhancing thermal stability and torque capacity, making the improved design a more reliable choice for high-performance applications subject to significant thermal fluctuations. This research highlights the critical role of material selection, thermal management, and precise design adjustments in optimizing the performance and reliability of permanent magnet synchronous motors. Full article

(This article belongs to the Special Issue The Energy Efficiency of Electric Vehicle Charging Stations with Minimal Grid Impact)

9 pages, 518 KiB

Open AccessArticle

Percutaneous Epidural Neuroplasty for Symptomatic Lumbar Juxtafacet Cysts

by Juneyoung Heo, Hyung-Ki Park, Ji-Hoon Baek, Hye-Sun Ahn and Su-Chan Lee

Medicina 2024, 60(7), 1042; https://doi.org/10.3390/medicina60071042 - 25 Jun 2024

Abstract

Background and Objectives: The term “Juxtafacet cyst” refers to both synovial cysts and ganglion pseudocysts associated with the lumbar facet joint. As conservative treatment for the juxtafacet cyst has a minimal effect, complete excision through surgery is considered the first choice of treatment. In this study, we retrospectively reviewed the clinical outcomes of percutaneous epidural neuroplasty for symptomatic lumbar juxtafacet cysts. Materials and Methods: We conducted a retrospective review of 34 patients with symptomatic juxtafacet cysts who visited a single institute from January 2010 to September 2023. Patients who received conservative treatment for at least 6 weeks but experienced no or insufficient effects were eligible for this study. After neuroplasty, a medical history check and neurological examination were performed during follow-up at 2 weeks, 1 month, 2 months, 3 months, 6 months, and once a year thereafter. Results: The pain improved for all patients to a VAS score of 3 or less immediately after neuroplasty; however, four of those patients (11%) had pain that worsened eventually to the same level as before the procedure and required surgery. The results showed that, regardless of cyst size, in cases with severe stenosis of the spinal canal, the outcome of neuroplasty was poor and often eventually required surgery. The cyst size was not associated with the procedure results. In addition, if the cyst was present at the L4–L5 level, or if diabetes mellitus was present, the likelihood of future surgery was significant (p-value = 0.003). Conclusions: Percutaneous neuroplasty showed a better success rate than other non-surgical treatments. In addition, severe spinal stenosis (Schizas grade C or higher), L4–L5 level, or diabetes mellitus produced a high possibility of surgery due to recurrence. Full article

(This article belongs to the Section Surgery)

13 pages, 1577 KiB

Open AccessArticle

Evaluation of Oxidative Stress and Endothelial Dysfunction in COVID-19 Patients

by Nurcan Kırıcı Berber, Osman Kurt, Ayşegül Altıntop Geçkil, Mehmet Erdem, Tuğba Raika Kıran, Önder Otlu, Seval Müzeyyen Ecin and Erdal İn

Medicina 2024, 60(7), 1041; https://doi.org/10.3390/medicina60071041 - 25 Jun 2024

Abstract

Background and Objectives: Heat shock proteins (HSPs) are stress proteins. The endogenous nitric oxide (NO) synthase inhibitor asymmetric dimethyl arginine (ADMA) is a mediator of endothelial dysfunction. Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) virus causes endothelial dysfunction and coagulopathy through severe inflammation and oxidative stress. Using these markers, we analyzed the prognostic value of serum ADMA and HSP-90 levels for early prediction of severe coronavirus disease (COVID-19) patients. Materials and Methods: A total of 76 COVID-19 patients and 35 healthy control subjects were included in this case–control study. COVID-19 patients were divided into two groups: mild and severe. Results: Serum ADMA and HSP-90 levels were significantly higher in the COVID-19 patients compared to the control subjects (p < 0.001). Additionally, serum ADMA and HSP-90 levels were determined to be higher in a statistically significant way in severe COVID-19 compared to mild COVID-19 (p < 0.001). Univariable logistic regression analysis revealed that ADMA and HSP-90, respectively, were independent predictors of severe disease in COVID-19 patients (ADMA (OR = 1.099, 95% CI = 1.048–1.152, p < 0.001) and HSP-90 (OR = 5.296, 95% CI = 1.719–16.316, p = 0.004)). When the cut-off value for ADMA was determined as 208.94 for the prediction of the severity of COVID-19 patients, the sensitivity was 72.9% and the specificity was 100% (AUC = 0.938, 95%CI = 0.858–0.981, p < 0.001). When the cut-off value for HSP-90 was determined as 12.68 for the prediction of the severity of COVID-19 patients, the sensitivity was 88.1% and the specificity was 100% (AUC = 0.975, 95% CI= 0.910–0.997, p < 0.001). Conclusions: Increased levels of Heat shock proteins-90 (HSP-90) and ADMA were positively correlated with increased endothelial damage in COVID-19 patients, suggesting that treatments focused on preventing and improving endothelial dysfunction could significantly improve the outcomes and reduce the mortality rate of COVID-19. ADMA and HSP-90 might be simple, useful, and prognostic biomarkers that can be utilized to predict patients who are at high risk of severe disease due to COVID-19. Full article

(This article belongs to the Section Infectious Disease)

► Show Figures

Figure 1

---

Figure 2 Cont.

---

Figure 3

22 pages, 30131 KiB

Open AccessArticle

Satellite Image Cloud Automatic Annotator with Uncertainty Estimation

by Yijiang Gao, Yang Shao, Rui Jiang, Xubing Yang and Li Zhang

Fire 2024, 7(7), 212; https://doi.org/10.3390/fire7070212 - 25 Jun 2024

Abstract

In satellite imagery, clouds obstruct the ground information, directly impacting various downstream applications. Thus, cloud annotation/cloud detection serves as the initial preprocessing step in remote sensing image analysis. Recently, deep learning methods have significantly improved in the field of cloud detection, but training these methods necessitates abundant annotated data, which requires experts with professional domain knowledge. Moreover, the influx of remote sensing data from new satellites has further led to an increase in the cost of cloud annotation. To address the dependence on labeled datasets and professional domain knowledge, this paper proposes an automatic cloud annotation method for satellite remote sensing images, CloudAUE. Unlike traditional approaches, CloudAUE does not rely on labeled training datasets and can be operated by users without domain expertise. To handle the irregular shapes of clouds, CloudAUE firstly employs a convex hull algorithm for selecting cloud and non-cloud regions by polygons. When selecting convex hulls, the cloud region is first selected, and points at the edges of the cloud region are sequentially selected as polygon vertices to form a polygon that includes the cloud region. Then, the same selection is performed on non-cloud regions. Subsequently, the fast KD-Tree algorithm is used for pixel classification. Finally, an uncertainty method is proposed to evaluate the quality of annotation. When the confidence value of the image exceeds a preset threshold, the annotation process terminates and achieves satisfactory results. When the value falls below the threshold, the image needs to undergo a subsequent round of annotation. Through experiments on two labeled datasets, HRC and Landsat 8, CloudAUE demonstrates comparable or superior accuracy to deep learning algorithms, and requires only one to two annotations to obtain ideal results. An unlabeled self-built Google Earth dataset is utilized to validate the effectiveness and generalizability of CloudAUE. To show the extension capabilities in various fields, CloudAUE also achieves desirable results on a forest fire dataset. Finally, some suggestions are provided to improve annotation performance and reduce the number of annotations. Full article

(This article belongs to the Special Issue Intelligent Forest Fire Prediction and Detection)

19 pages, 1262 KiB

Open AccessArticle

Pore Structure Characterization and Fractal Characteristics of Tight Limestone Based on Low-Temperature Nitrogen Adsorption and Nuclear Magnetic Resonance

by Wei Lin, Xinli Zhao, Mingtao Li and Yan Zhuang

Fractal Fract. 2024, 8(7), 371; https://doi.org/10.3390/fractalfract8070371 - 25 Jun 2024

Abstract

Pore structure characterization and fractal analysis have great significance for understanding and evaluating tight limestone reservoirs. In this work, the pore structure of tight limestone, low-temperature nitrogen adsorption (LTNA), and low-field nuclear magnetic resonance (NMR) are characterized, and the fractal dimension of the pore structure of tight limestone is discussed based on LTNA and NMR data. The results indicate that the pores of tight limestone have H3 and H4 types, the pore size distribution (PSD) of the H3 type is a wave distribution ranging from 2 to 10 nm, and the PSD of the H4 type is a unimodal distribution ranging from 2 to 10 nm. The transverse relaxation time (T₂) spectrum of tight limestone shows a single peak (DF), double peak (SF), and triple peak (TF), and the ranges for the T₂ spectra for micropores, mesopores, and macropores are 0.1 to 10 ms, 10 to 100 ms, and greater than 100 ms, respectively. The LTNA fractal dimension of tight limestone (D_L) ranges between 2.4446 and 2.7688, with an average of 2.5729, and the NMR fractal dimensions of micropores (D_NMR1), mesopores (D_NMR2), and macropores (D_NMR3) are distributed between 0.3744 and 1.1293, 2.4263 and 2.9395, and 2.6582 and 2.9989, respectively. Moreover, there is a negative correlation between D_L and average pore radius, a positive correlation between D_L and specific surface area, and a positive correlation between D_NMR2 and D_NMR3 and micropore content, while D_NMR2 and D_NMR3are negatively correlated with the content of mesopores and macropores. Full article

(This article belongs to the Special Issue Pore Structure and Fractal Characteristics in Unconventional Oil and Gas Reservoirs)

18 pages, 2169 KiB

Open AccessArticle

A Fractal Adsorption Model on Methane in Coal with Temperature Effect Dependence

by Fei Guo, Gaofeng Liu, Zhen Zhang, Runsheng Lv, Baoan Xian, Jia Lin, George Barakos and Ping Chang

Fractal Fract. 2024, 8(7), 370; https://doi.org/10.3390/fractalfract8070370 - 25 Jun 2024

Abstract

The traditional Langmuir equation displays drawback in accurately characterizing the methane adsorption behavior in coal, due to it assuming the uniform surface of coal pores. Additionally, the decay law of gas adsorption capacity with an increasing coal reservoir temperature remains unknown. In this study, the fractal adsorption model is proposed based on the fractal dimension (D_f) of coal pores and the attenuation coefficient (n) of the adsorption capacity. The principles and methods of this fractal adsorption model are deduced and summarized in detail. The results show that the pore structures of the two coal samples exhibit obvious fractal characteristics, with the values of fractal dimensions (D_f) being 2.6279 and 2.93. The values of adsorption capacity attenuation coefficients (n) are estimated as −0.006 and −0.004 by the adsorption experiments with different temperatures. The proposed fractal adsorption model presents a greater theoretical significance and higher accuracy than that of the Langmuir equation. The accuracy of the fractal adsorption model with temperature effect dependence is verified, establishing a prediction method for methane adsorption capacity in deep coal reservoirs. This study can serve as a theoretical foundation for coalbed methane exploration and development, as well as provide valuable insights for unconventional natural gas exploitation. Full article

(This article belongs to the Section Engineering)

33 pages, 742 KiB

Open AccessReview

A Brief Review of Fractional Calculus as a Tool for Applications in Physics: Adsorption Phenomena and Electrical Impedance in Complex Fluids

by Giovanni Barbero, Luiz. R. Evangelista, Rafael S. Zola, Ervin K. Lenzi and Antonio M. Scarfone

Fractal Fract. 2024, 8(7), 369; https://doi.org/10.3390/fractalfract8070369 - 25 Jun 2024

Abstract

Many fundamental physical problems are modeled using differential equations, describing time- and space-dependent variables from conservation laws. Practical problems, such as surface morphology, particle interactions, and memory effects, reveal the limitations of traditional tools. Fractional calculus is a valuable tool for these issues, with applications ranging from membrane diffusion to electrical response of complex fluids, particularly electrolytic cells like liquid crystal cells. This paper presents the main fractional tools to formulate a diffusive model regarding time-fractional derivatives and modify the continuity equations stating the conservation laws. We explore two possible ways to introduce time-fractional derivatives to extend the continuity equations to the field of arbitrary-order derivatives. This investigation is essential, because while the mathematical description of neutral particle diffusion has been extensively covered by various authors, a comprehensive treatment of the problem for electrically charged particles remains in its early stages. For this reason, after presenting the appropriate mathematical tools based on fractional calculus, we demonstrate that generalizing the diffusion equation leads to a generalized definition of the displacement current. This modification has strong implications in defining the electrical impedance of electrolytic cells but, more importantly, in the formulation of the Maxwell equations in material systems. Full article

(This article belongs to the Special Issue Anomalous Diffusion and Relaxations in Liquid Crystals: Fractal and Fractional Behavior)

23 pages, 2961 KiB

Open AccessArticle

Advancing Convergence Speed of Distributed Consensus Time Synchronization Algorithms in Unmanned Aerial Vehicle Ad Hoc Networks

by Jianfeng Wu, Kaiyuan Bai and Huabing Wu

Drones 2024, 8(7), 285; https://doi.org/10.3390/drones8070285 - 25 Jun 2024

Abstract

Time synchronization is a critical prerequisite for unmanned aerial vehicle ad hoc networks (UANETs) to facilitate navigation and positioning, formation control, and data fusion. However, given the dynamic changes in UANETs, improving the convergence speeds of distributed consensus time synchronization algorithms with only local information poses a major challenge. To address this challenge, this study first establishes a convex model on the basis of graph theory and relevant theories of random matrices to approximate the original problem. Subsequently, three acceleration schemes for consensus algorithms are derived by minimizing the Frobenius norm of the iteration matrix. Additionally, this study provides a new upper bound for constant communication weights and discusses the limitations of existing metrics used to measure the convergence speeds of consensus algorithms. Finally, the proposed schemes are compared with existing ones through simulation. Our results indicate that the three proposed schemes can achieve faster convergence while maintaining high-precision synchronization in scenarios with static or known topological structures of networks. In scenarios where the topological structure of a UANET is time-varying and unknown, the scheme proposed in this paper achieves the fastest convergence speed. Full article

(This article belongs to the Topic Cooperative Localization, Optimization and Control of Networked Autonomous Systems: Theories, Analysis Tools and Applications)

16 pages, 3820 KiB

Open AccessArticle

Preparation and Characterization of Particleboard Made from Industrial-Type Wood Particles and Discarded Duck Feathers

by Nidal Del Valle Raydan, Bertrand Charrier, Grzegorz Kowaluk and Eduardo Robles

J. Compos. Sci. 2024, 8(7), 241; https://doi.org/10.3390/jcs8070241 - 25 Jun 2024

Abstract

Global poultry waste production is substantial, with billions of poultry raised annually for meat and egg production, resulting in significant feather waste. Conventional poultry waste disposal methods are restricted due to environmental concerns. Meanwhile, wood-composite panel industries face raw material shortages, emphasizing the need for sustainable, renewable fiber sources. In this study, in the core layer of panels, wood particles were replaced with 5 wt% clean duck feathers without pretreatment to take advantage of feather attributes like hydrophobicity, thermal insulation, and sound damping as an alternative construction material. Three adhesives—urea-formaldehyde (UF), polymeric 4,4′-diphenylmethane diisocyanate (pMDI), and polyvinyl acetate (PVAc)—were examined for resin–feather compatibility. The control panels in this study were identical but wood was not replaced with feathers. The results revealed that wood–feather particleboard with pMDI and PVAc resins meets the requirements of the relevant standard for P2 boards (where applicable) concerning their modulus of rupture (MOR: 11 N·mm⁻²), modulus of elasticity (MOE: 1600 N·mm⁻²), internal bond (IB: 0.35 N·mm⁻²), and screw withdrawal resistance (SWR). However, those produced with UF resin did not meet the standards for IB and MOE. Furthermore, the physical properties showed similar water resistance and thickness swelling to control panels with pMDI. Notably, substituting 5 wt% wood with feathers improved thermal insulation by approximately 10% for UF and pMDI resins. Additionally, particleboard with feathers demonstrated improved sound absorption at high frequencies, ranging from 2500 to 500 Hz, particularly with pMDI resin, approaching Class B classification according to EN ISO 11654:1997. This study identifies the higher compatibility of pMDI over PVAc and UF adhesives for feather-based composite materials in construction applications. Full article

(This article belongs to the Special Issue From Waste to Advance Composite Materials)

23 pages, 7358 KiB

Open AccessArticle

Effect of PVDF, HA, and AgNO₃ Annealing on β-Phase, Optical, and Mechanical Properties

by Ieva Markuniene, Arvydas Palevicius, Joris Vezys, Jakub Augustyniak, Dariusz Perkowski, Sigita Urbaite and Giedrius Janusas

J. Compos. Sci. 2024, 8(7), 240; https://doi.org/10.3390/jcs8070240 - 25 Jun 2024

Abstract

Typically, polymer composites and ceramics are used to create biosensors. Materials with properties that are ideal for biosensors and chemical sensors include AgNO₃ (silver nitrate), PVDF (polyvinylidene fluoride), and HA (hydroxyapatite). Polyvinylidene fluoride (PVDF) polymer has been widely used in several applications because of its well-known superior ferroelectric characteristics and biocompatibility. The brittleness and low bending strength of hydroxyapatite limit its applicability. Several HA and polymer composite formulations have been developed to compensate for HA’s mechanical weakness. The final product contains a significant amount of HA, making HA/polymer composites highly biocompatible. When the right amount of silver is deposited, the maximum piezoelectric activity is generated, and silver nitrate has antimicrobial properties. The non-toxic solvent DMSO (dimethyl sulfoxide) and the solvent casting method were chosen for the preparation of the film. Surface roughness was chosen to measure the Str and Sdr properties of the thin film. For liquid preparation, the multifractal spectra analysis was chosen for each sample. SEM was used to examine the samples morphologically. EDX and mapping analyses were presented for chemistry distribution in the samples. Full article

(This article belongs to the Special Issue Progress in Polymer Composites, Volume III)

18 pages, 929 KiB

Open AccessArticle

Improved Expression of Aggregation-Prone Tau Proteins Using a Spidroin-Derived Solubility Tag

by Kevin Muwonge, Bedri Yaman, Attila Mészáros, Giorgio Russo, Alexander Volkov and Peter Tompa

Separations 2024, 11(7), 198; https://doi.org/10.3390/separations11070198 - 25 Jun 2024

Abstract

Tauopathies, a group of neurodegenerative disorders, are characterized by the abnormal aggregation of microtubule-associated Tau proteins in neurons and glial cells. The process of Tau proteins transitioning from soluble, intrinsically disordered monomers to disease-associated aggregates is still unclear. Investigating these molecular mechanisms requires the reconstitution of such processes in cellular and in vitro models using recombinant proteins at high purity and yield. However, the production of phase-separating or aggregation-prone recombinant proteins like Tau’s hydrophobic-rich domains or disease mutation-carrying variants on a large scale is highly challenging due to their limited solubility. To overcome this challenge, we have developed an improved strategy for expressing and purifying recombinant Tau proteins using the major ampullate spidroin-derived solubility tag (MaSp-NT*). This approach involves using NT* as a fusion tag to enhance the solubility and stability of expressed proteins by forming micelle-like particles within the cytosol of E. coli cells. We found that fusion with the NT* tag significantly increased the solubility and yield of highly hydrophobic and/or aggregation-prone Tau constructs. Our purification method for NT* fusion proteins yielded up to twenty-fold higher amounts than proteins purified using our novel tandem-tag (6xHis-SUMO-Tau-Heparin) purification system. This enhanced expression and yield were demonstrated with full-length Tau (hT40/Tau441), its particularly aggregation-prone repeat domain (Tau-MTBR), and Frontotemporal dementia (FTD)-associated mutant (Tau-P301L). These advancements offer promising avenues for the production of large quantities of Tau proteins suitable for in vitro experimental techniques such as nuclear magnetic resonance (NMR) spectroscopy without the need for a boiling step, bringing us closer to effective treatments for tauopathies. Full article

(This article belongs to the Special Issue Peptide Synthesis, Separation and Purification)

13 pages, 605 KiB

Open AccessArticle

Post-Arthroplasty Spatiotemporal Gait Parameters in Patients with Hip Osteoarthritis or Developmental Dysplasia of the Hip: An Observational Study

by Sophia Stasi, Georgios Papagiannis, Athanasios Triantafyllou, Panayiotis Papagelopoulos and Panagiotis Koulouvaris

J. Funct. Morphol. Kinesiol. 2024, 9(3), 110; https://doi.org/10.3390/jfmk9030110 - 25 Jun 2024

Abstract

Total hip arthroplasty (THA) is a preferred treatment for primary osteoarthritis (OA) or secondary degenerative arthropathy due to developmental hip dysplasia (DDH). Gait analysis is considered a gold standard for evaluating post-arthroplasty walking patterns. This study compared post-THA spatiotemporal gait parameters (SGPs) between OA and DDH patients and explored correlations with demographic and clinical variables. Thirty patients (15 per group) were recorded during gait and their SGPs were analyzed. Functionality was evaluated with the Oxford Hip Score (OHS). The OA patients were significantly older than DDH patients (p < 0.005). Significant and moderate to strong were the correlations between SGPs, age, and four items of the OHS concerning hip pain and activities of daily life (0.31 < Pearson’s r < 0.51 all p < 0.05). Following THA, both groups exhibited similar levels of the examined gait parameters. Post-arthroplasty SGPs and OHS correlations indicate limitations in certain activities. Given the absence of pre-operative data and the correlation between age and SGPs and OHS, ANCOVA testing revealed that age adjusts OHS and SGP values, while pre-operative diagnosis has no main effect. These findings indicate that hip OA or DDH do not affect postoperative SGPs and patients’ functionality. Future studies should examine both kinematic and kinetic data to better evaluate the post-THA gait patterns of OA and DDH patients. Full article

(This article belongs to the Special Issue Biomechanical Analysis in Physical Activity and Sports)

12 pages, 1330 KiB

Open AccessArticle

Effects of Acute Temperature Stress on the Expression of Related Genes in the Brain of Opsariichthys bidens

by Qianhui Li, Luomei Xiong, Yechen Zhu, Anrui Zheng and Shanjian Zheng

Fishes 2024, 9(7), 248; https://doi.org/10.3390/fishes9070248 - 25 Jun 2024

Abstract

Opsariichthys bidens (O. bidens) is a fish species native to China and sensitive to temperature changes. In this study, the effects of acute temperature stress on brain gene expression in O. bidens were investigated by sampling brain tissues from specimens exposed to three different temperatures (15 °C, 25 °C, and 35 °C) for varying durations of 2 h, 4 h, 6 h, and 8 h. The study focused on analyzing the expression patterns of key genes implicated in neural function and stress response, including brain-derived neurotrophic factor (BDNF), c-FOS, heat shock proteins (HSP70, HSP90), endoplasmic reticulum stress markers (IRE1, GRP78), oxidative stress enzymes (CAT, SOD), and apoptotic regulators (caspase3, Bax). The findings revealed that upon exposure to acute heat stress, the expression levels of the aforementioned genes in the brain of O. bidens were up-regulated within 2 h, peaking at the 4-h mark. Conversely, following acute cold stress, the expression of c-FOS, BDNF, HSP70, HSP90, SOD, and CAT genes increased significantly after 4 h, while caspase3 expression was notably elevated at the 6-h mark, with no significant impact observed on Bax, IRE1, or GRP78 gene expression levels. The study suggested that the brain of O. bidens responds to high temperatures through mechanisms involving neural activation, heat shock proteins, endoplasmic reticulum stress, oxidative stress, and apoptosis. Similarly, adaptation to low temperatures by O. bidens’ brain was associated with neural activation, regulation of heat shock proteins, oxidative stress responses, and apoptotic processes. Overall, this research aimed to elucidate the impact of temperature stress on brain physiology and the adaptive mechanisms of O. bidens at the genetic level, providing a foundational understanding of its temperature adaptation strategies. Full article

(This article belongs to the Section Biology and Ecology)

14 pages, 964 KiB

Open AccessArticle

Feeding Behaviour of Seven Icefish Species (Channichthyidae) in the Ross Sea, Antarctica

by Erica Carlig, Davide Di Blasi, Laura Ghigliotti, Andreas Scalas, Andrew L. Stewart and Michela Mortara

Fishes 2024, 9(7), 247; https://doi.org/10.3390/fishes9070247 - 25 Jun 2024

Abstract

The Channichthyidae, a monophyletic fish group belonging to the suborder Notothenioidei, are uniquely adapted to the polar environment. However, while their physiology has been extensively studied, studies on their ecology are relatively rare. Here, we investigated the trophic ecology of seven icefish species (Chaenodraco wilsoni, Chionobathyscus dewitti, Chionodraco hamatus, Dacodraco hunteri, Neopagetopis ionah, Pagetodes antarcticus and Pagetopsis macropterus) by using the traditional morphometric approach to assess the relationship between form and feeding function. The suction index (SI), the mechanical advantage in jaw closing (MA) and nine morphological traits related to feeding structures have been analysed. Icefish species are characterised by non-protractible, elongate jaws and a wide gape; such morphological features influence the low values of both MA and SI, supporting their ram-feeding habit. The ecomorphological differences among species resulted mainly determined by the anatomical structures related to SI. Such differences do not seem to be determined primarily by the type of prey, as is the case in other taxonomic groups of Notothenioidei, but rather by phylogenetic proximity. A 3D animation was developed to visualise the different feeding modes of two icefish species (C. hamatus and P. macropterus) which are characterised by different approaches to prey. Full article

(This article belongs to the Special Issue Recent Advances in Foraging Behavior of Fish)

16 pages, 1277 KiB

Open AccessArticle

Design and Verification of Piano Playing Assisted Hand Exoskeleton Robot

by Qiujian Xu, Dan Yang, Meihui Li, Xiubo Ren, Xinran Yuan, Lijun Tang, Xiaoyu Wang, Siqi Liu, Miaomiao Yang, Yintong Liu and Mingyi Yang

Biomimetics 2024, 9(7), 385; https://doi.org/10.3390/biomimetics9070385 - 25 Jun 2024

Abstract

Finger technique is a crucial aspect of piano learning, and hand exoskeleton mechanisms effectively assist novice piano players in maintaining correct finger technique consistently. Addressing current issues with exoskeleton robots, such as the inability to provide continuous correction of finger technique and their considerable weight, a novel hand exoskeleton robot has been developed to enhance finger technique through continuous correction and reduced weight. Initial data are gathered using finger joint angle sensors to analyze movements during piano playing, focusing on the trajectory and angular velocity of key strikes. This analysis informs the design of a 6-bar double-closed-loop mechanism with an end equivalent sliding pair, using analytical methods to establish the relationship between motor extension and input rod rotation. Simulation studies assess the exoskeleton’s motion space and dynamics, confirming its capability to meet structural and functional demands for accurate key striking. Prototype testing validates the exoskeleton’s ability to maintain correct finger positioning and mimic natural strike speeds, thus improving playing technique while ensuring comfort and safety. Full article

(This article belongs to the Special Issue Design and Control of a Bio-Inspired Robot: 2nd Edition)

18 pages, 2065 KiB

Open AccessArticle

Multi-UAV Cooperative Coverage Search for Various Regions Based on Differential Evolution Algorithm

by Hui Zeng, Lei Tong and Xuewen Xia

Biomimetics 2024, 9(7), 384; https://doi.org/10.3390/biomimetics9070384 - 25 Jun 2024

Abstract

In recent years, remotely controlling an unmanned aerial vehicle (UAV) to perform coverage search missions has become increasingly popular due to the advantages of the UAV, such as small size, high maneuverability, and low cost. However, due to the distance limitations of the remote control and endurance of a UAV, a single UAV cannot effectively perform a search mission in various and complex regions. Thus, using a group of UAVs to deal with coverage search missions has become a research hotspot in the last decade. In this paper, a differential evolution (DE)-based multi-UAV cooperative coverage algorithm is proposed to deal with the coverage tasks in different regions. In the proposed algorithm, named DECSMU, the entire coverage process is divided into many coverage stages. Before each coverage stage, every UAV automatically plans its flight path based on DE. To obtain a promising flight trajectory for a UAV, a dynamic reward function is designed to evaluate the quality of the planned path in terms of the coverage rate and the energy consumption of the UAV. In each coverage stage, an information interaction between different UAVs is carried out through a communication network, and a distributed model predictive control is used to realize the collaborative coverage of multiple UAVs. The experimental results show that the strategy can achieve high coverage and a low energy consumption index under the constraints of collision avoidance. The favorable performance in DECSMU on different regions also demonstrate that it has outstanding stability and generality. Full article

(This article belongs to the Special Issue Bio-Inspired Optimization Algorithms and Designs for Engineering Applications: 2nd Edition)

24 pages, 688 KiB

Open AccessArticle

Optimal Battery Energy Storage Dispatch for the Day-Ahead Electricity Market

by Julio Gonzalez-Saenz and Victor Becerra

Batteries 2024, 10(7), 228; https://doi.org/10.3390/batteries10070228 - 25 Jun 2024

Abstract

This work presents an innovative application of optimal control theory to the strategic scheduling of battery storage in the day-ahead electricity market, focusing on enhancing profitability while factoring in battery degradation. This study incorporates the effects of battery degradation on the dynamics in the optimisation framework. Considering this cost in economic analysis and operational strategies is essential to optimise long-term performance and economic viability. Neglecting degradation costs can lead to suboptimal operation and dispatch strategies. We employ a continuous-time representation of the dynamics, in contrast with many other studies that use a discrete-time approximation with rather coarse intervals. We adopt an equivalent circuit model coupled with empirical degradation parameters to simulate a battery cell’s behaviour and degradation mechanisms with good support from experimental data. Utilising direct collocation methods with mesh refinement allows for precise numerical solutions to the complex, nonlinear dynamics involved. Through a detailed case study of Belgium’s day-ahead electricity market, we determine the optimal charging and discharging schedules under varying objectives: maximising net revenues, maximising profits considering capacity degradation, and maximising profits considering both capacity degradation and internal resistance increase due to degradation. The results demonstrate the viability of our approach and underscore the significance of integrating degradation costs into the market strategy for battery operators, alongside its effects on the battery’s dynamic behaviour. Our methodology extends previous work by offering a more comprehensive model that empirically captures the intricacies of battery degradation, including a fine and adaptive time domain representation, focusing on the day-ahead market, and utilising accurate direct methods for optimal control. This paper concludes with insights into the potential of optimal control applications in energy markets and suggestions for future research avenues. Full article

(This article belongs to the Special Issue Advanced Control and Optimization of Battery Energy Storage Systems)

17 pages, 1269 KiB

Open AccessArticle

Utilizing Electronic Resistance Measurement for Tailoring Lithium-Ion Battery Cathode Formulations

by Christoph Seidl, Sören Thieme, Martin Frey, Kristian Nikolowski and Alexander Michaelis

Batteries 2024, 10(7), 227; https://doi.org/10.3390/batteries10070227 - 25 Jun 2024

Abstract

Cathode formulation, which describes the amount of cathode active material (CAM), conductive additives (CAs), and binder within a cathode compound, is decisive for the performance metrics of lithium-ion battery (LIB) cells. The direct measurement of electronic resistance can be an enabler for more time- and cost-efficient cathode formulation improvements. Within this work, we correlate the electronic resistance with the electrochemical performance of cathodes. Two different high Nickel NCM cathode materials and numerous CAs are used to validate the findings. A detailed look into the resistance reduction potential of carbon black (CB) and single-walled carbon nanotubes (SWCNT) and their mixtures is made. Finally, an impact estimation of cathode formulation changes on LIB key performance factors, such as energy density and cost, is shown. Full article

(This article belongs to the Section Battery Performance, Ageing, Reliability and Safety)

16 pages, 1488 KiB

Open AccessArticle

Human Health Benefits and Microbial Consortium of Stevia Fermented with Barley Nuruk

by Hyun-Ju Han, Min Nyeong Ko, Chan Seong Shin and Chang-Gu Hyun

Fermentation 2024, 10(7), 330; https://doi.org/10.3390/fermentation10070330 - 25 Jun 2024

Abstract

In this study, the microbial community present during the barley yeast fermentation of stevia leaves and its correlation with antioxidant, anti-obesity, and anti-inflammatory properties, as well as metabolites, were investigated using UPLC-Q-TOF-MS. Stevia was fermented using commercial TSB media (TSB 1, TSB 3, and TSB 5) and sucrose (Sucrose 1, Sucrose 3, and Sucrose 5) for 1, 3, and 5 days, respectively. Stevia ferments showed higher DPPH and ABTS radical scavenging capacity compared to samples incubated with sucrose for 5 days, and all six ferments inhibited nitric oxide production in a concentration-dependent manner in LPS-induced mouse macrophages. Furthermore, UPLC-QTOF-MS analysis identified 23 related substances, including 10 terpenoids (including rubusoside, steviolbioside, and rebadioside derivatives), dulcoside A, and phlomisoside II, which are indicators of stevia, as well as five flavonoids, four phenolic acids, and four fatty acids. We also identified the microbial community during fermentation via the next-generation sequencing of the 16S rRNA gene for bacteria and the internal transcribed spacer (ITS) gene for fungi. The results showed that TSB 1 and Sucrose 1 ferments were dominated by the pathogens Enterococcus hirae (58.93%) and Cronobacter sakazakii (80.92%), while samples fermented for more than 3 days were pathogen-free and dominated by lactic acid bacteria such as Pediococcus stilesii (73.37%). Microbial community analysis using the ITS region showed that Saccharomycopsis fibuligera, classified as a yeast rather than a mold, dominated the stevia fermentation regardless of the fermentation duration. In particular, the microbial community of the fermentation with a sucrose solution was dominated by S. fibuligera by more than 99% throughout the fermentation periods of 1, 3, and 5 days. Finally, to apply the stevia ferments topically to human skin, skin irritation tests were performed on 30 volunteers. The results showed that the highly concentrated extracts (1 mg/mL) of all six stevia ferments were hypoallergenic. Taken together, these findings suggest that barley nuruk fermented from stevia leaves with a sucrose solution offers promise as a natural ingredient for use in functional foods and cosmetics. Full article

(This article belongs to the Special Issue Functional Properties of Microorganisms in Fermented Foods)

4 pages, 403 KiB

Open AccessEditorial

Molecular Mechanisms and Clinical Implications of Noncoding RNAs in Cancer

by Jin Wang, Xiaomeng He and Christopher Corpe

Non-Coding RNA 2024, 10(4), 37; https://doi.org/10.3390/ncrna10040037 - 25 Jun 2024

Abstract

Noncoding RNAs (ncRNAs), which include small nuclear RNAs (snRMAs), small nucleolar RNAs (snoRNAs), microRNAs (miRNAs), long noncoding RNAs (lncRNAs), and circular RNAs (circRNAs), are RNA molecules that arise from genomic regions without protein-coding potential and display a variety of mechanisms and functions by regulating gene expression at the transcriptional, RNA processing, and translational levels and participating in virtually all cellular processes [...] Full article

(This article belongs to the Special Issue Molecular Mechanisms and Clinical Implications of Non-coding RNAs in Cancer)

15 pages, 421 KiB

Open AccessArticle

Asymmetry in Cost Behavior in Brazilian Hospitals

by Josiane Da Conceição Bitela Da Silva, Tany Ingrid Sagredo Marin, Katia Abbas, Luiz Eduardo Gaio, Carlos Alberto Grespan Bonacim and Rafael Confetti Gatsios

J. Risk Financial Manag. 2024, 17(7), 260; https://doi.org/10.3390/jrfm17070260 - 25 Jun 2024

Abstract

Abstract: Objectives: Investigating if the proportion of fixed assets over total assets is positively associated with the asymmetric cost behavior of public and private hospitals in Brazil. Methods: In order to test the sticky cost phenomenon in a different sector of companies and industries, we used panel data regression to investigate the asymmetric cost behavior in Brazilian hospitals, analyzing the hospital cost behavior regarding the variation in revenues and verifying whether the proportion of fixed assets over total assets is positively associated with the asymmetric cost behavior. As a result, this research took the findings obtained by the models applied to data from the 101 hospitals comprising the sample, spread over the 2010–2019 period. The research was divided into four sections. The first section tested asymmetry for fixed assets over total assets for hospitals in general. The second section divided the sample into public and private hospitals. The third section analyzed the sample of conglomerates against a single hospital. Finally, the fourth section tested the asymmetry of the hospitals in the sample measured by the number of beds. Results: The evidence documented here partially confirms the results of literature on the existence of asymmetric cost behavior regarding variations in revenue. The H₁ hypothesis that the proportion of fixed assets over total assets is positively associated with the asymmetric cost behavior was confirmed, especially for private and small hospitals regarding fixed assets. Full article

(This article belongs to the Section Economics and Finance)

11 pages, 652 KiB

Open AccessArticle

BeGraft Aortic Stents: A European Multi-Centre Experience Reporting Acute Safety and Efficacy Outcomes for the Treatment of Vessel Stenosis in Congenital Heart Diseases

by Micol Rebonato, Mara Pilati, Sophie Malekzadeh Milani, Damien Bonnet, Emma Pascall, Matthew Jones, Pedro Betrian, Lisa Bianco, Hugues Lucron, Sebastien Hascoet, Alban-Elouen Baruteau, Luca Giugno and Gianfranco Butera

J. Cardiovasc. Dev. Dis. 2024, 11(7), 192; https://doi.org/10.3390/jcdd11070192 - 25 Jun 2024

Abstract

Background: Stent implantation has become the preferred method of treatment for treating vessel stenosis in congenital heart diseases. The availability of covered stents may decrease complications and have an important role in the management of patients with complex anatomy. Aim: This study aims to evaluate the feasibility and safety of the pre-mounted cobalt–chromium stent-graft-covered ePTFE Aortic BeGraft in a broad spectrum of vascular lesions. Methods: This is a multicenter retrospective results analysis of 107 implanted BeGraft stents between 2016 and 2022 in six different European centers. Results: One hundred and four patients with a mean age of thirteen years (range 1–70 years) and with the body weight of 56.5 kg (range 11–115 kg) underwent the BeGraft stent implantation. Stents were implanted in the following conditions: aortic coarctation (74 patients), RVOT dysfunction (12 patients), Fontan circulation (7 patients), and miscellaneous (11 subjects with complex CHD). All the stents were implanted successfully. The median stent diameter was 16 mm (range 7–24 mm), and the median length was 39 mm (range 19–49 mm). Major complications occurred in five subjects (4.7%). During a median follow-up of fourteen (1–70) months, stents’ re-dilatation was performed in five patients. Conclusions: The BeGraft stent can be used safely and effectively in a wide spectrum of congenital heart diseases. Whether these good results will be stable in the longer term still needs to be investigated in a follow-up given its recent introduction into clinical practice, in particular regarding stent fracture or neointimal proliferation. Full article

(This article belongs to the Special Issue Congenital Heart Disease: Technological Innovations in Cardiac Surgery and Interventional Therapy)

Recent Articles

Open Access Journals

Highly Accessed Articles

Latest Books

News

Blog Posts

Topics

Selected Special Issues

Selected Collections

Journals by Subject

Further Information

Guidelines

MDPI Initiatives

Follow MDPI