The 2023 MDPI Annual Report has
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17 pages, 4127 KiB  
Article
Exploring the Effect of Specimen Size on Elastic Properties of Fused-Filament-Fabrication-Printed Polycarbonate and Thermoplastic Polyurethane
by Charul Chadha, Gabriel Olaivar, Mahmoud A. Mahrous, Albert E. Patterson and Iwona Jasiuk
Materials 2024, 17(11), 2677; https://doi.org/10.3390/ma17112677 (registering DOI) - 1 Jun 2024
Abstract
Additive manufacturing (AM) is often used to create designs inspired by topology optimization and biological structures, yielding unique cross-sectional geometries spanning across scales. However, manufacturing defects intrinsic to AM can affect material properties, limiting the applicability of a uniform material model across diverse [...] Read more.
Additive manufacturing (AM) is often used to create designs inspired by topology optimization and biological structures, yielding unique cross-sectional geometries spanning across scales. However, manufacturing defects intrinsic to AM can affect material properties, limiting the applicability of a uniform material model across diverse cross-sections. To examine this phenomenon, this paper explores the influence of specimen size and layer height on the compressive modulus of polycarbonate (PC) and thermoplastic polyurethane (TPU) specimens fabricated using fused filament fabrication (FFF). Micro-computed tomography imaging and compression testing were conducted on the printed samples. The results indicate that while variations in the modulus were statistically significant due to both layer height and size of the specimen in TPU, variations in PC were only statistically significant due to layer height. The highest elastic modulus was observed at a 0.2 mm layer height for both materials across different sizes. These findings offer valuable insights into design components for FFF, emphasizing the importance of considering mechanical property variations due to feature size, especially in TPU. Furthermore, locations with a higher probability of failure are recommended to be printed closer to the print bed, especially for TPU, because of the lower void volume fraction observed near the heated print bed. Full article
(This article belongs to the Special Issue Advances in Additive Manufacturing (Volume II))
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15 pages, 706 KiB  
Article
Hemoglobin and Its Relationship with Fatigue in Long-COVID Patients Three to Six Months after SARS-CoV-2 Infection
by Somayeh Bazdar, Lizan D. Bloemsma, Nadia Baalbaki, Jelle M. Blankestijn, Merel E. B. Cornelissen, Rosanne J. H. C. G. Beijers, Brigitte M. Sondermeijer, Yolanda van Wijck, George S. Downward and Anke H. Maitland-van der Zee on behalf of the PO Consortium
Biomedicines 2024, 12(6), 1234; https://doi.org/10.3390/biomedicines12061234 (registering DOI) - 1 Jun 2024
Abstract
Background: While some long-term effects of COVID-19 are respiratory in nature, a non-respiratory effect gaining attention has been a decline in hemoglobin, potentially mediated by inflammatory processes. In this study, we examined the correlations between hemoglobin levels and inflammatory biomarkers and evaluated the [...] Read more.
Background: While some long-term effects of COVID-19 are respiratory in nature, a non-respiratory effect gaining attention has been a decline in hemoglobin, potentially mediated by inflammatory processes. In this study, we examined the correlations between hemoglobin levels and inflammatory biomarkers and evaluated the association between hemoglobin and fatigue in a cohort of Long-COVID patients. Methods: This prospective cohort study in the Netherlands evaluated 95 (mostly hospitalized) patients, aged 40–65 years, 3–6 months post SARS-CoV-2 infection, examining their venous hemoglobin concentration, anemia (hemoglobin < 7.5 mmol/L in women and <8.5 mmol/L in men), inflammatory blood biomarkers, average FSS (Fatigue Severity Score), demographics, and clinical features. Follow-up hemoglobin was compared against hemoglobin during acute infection. Spearman correlation was used for assessing the relationship between hemoglobin concentrations and inflammatory biomarkers, and the association between hemoglobin and fatigue was examined using logistic regression. Results: In total, 11 (16.4%) participants were suffering from anemia 3–6 months after SARS-CoV-2 infection. The mean hemoglobin value increased by 0.3 mmol/L 3–6 months after infection compared to the hemoglobin during the acute phase (p-value = 0.003). Whilst logistic regression showed that a 1 mmol/L greater increase in hemoglobin is related to a decrease in experiencing fatigue in Long-COVID patients (adjusted OR 0.38 [95%CI 0.13–1.09]), we observed no correlations between hemoglobin and any of the inflammatory biomarkers examined. Conclusion: Our results indicate that hemoglobin impairment might play a role in developing Long-COVID fatigue. Further investigation is necessary to identify the precise mechanism causing hemoglobin alteration in these patients. Full article
14 pages, 8217 KiB  
Article
In Situ Study of Precipitates’ Effect on Grain Deformation Behavior and Mechanical Properties of S31254 Super Austenitic Stainless Steel
by Jinyao Ma, Huanyu Tan, Nan Dong, Jiemin Gao, Puli Wang, Zhihua Wang and Peide Han
Materials 2024, 17(11), 2676; https://doi.org/10.3390/ma17112676 (registering DOI) - 1 Jun 2024
Abstract
Grain boundary (GB) precipitation-induced cracking is a significant issue for S31254 super austenitic stainless steel during hot working. Investigating the deformation behavior based on precipitate morphology and distribution is essential. In this study, continuous smaller and intermittent larger precipitates were obtained through heat [...] Read more.
Grain boundary (GB) precipitation-induced cracking is a significant issue for S31254 super austenitic stainless steel during hot working. Investigating the deformation behavior based on precipitate morphology and distribution is essential. In this study, continuous smaller and intermittent larger precipitates were obtained through heat treatments at 950 °C and 1050 °C. The microstructure evolution and mechanical properties influenced by precipitates were experimentally investigated using an in situ tensile stage inside a scanning electron microscope (SEM) combined with electron backscatter diffraction (EBSD). The results showed that continuous precipitates at 950 °C had a stronger pinning effect on the GB, making grain rotation difficult and promoting slip deformation in the plastic interval. Continuous precipitates caused severe stress concentration near GB and reduced coordinated deformation ability. Additionally, the crack propagation path changed from transcrystalline to intercrystalline. Furthermore, internal precipitates were a crucial factor affecting the initial crack nucleation position. Interconnected precipitates led to an intergranular fracture tendency and severe deterioration of the material’s plasticity, as observed in fracture morphology. Full article
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28 pages, 5613 KiB  
Article
Empowering Urban Public Transport Planning Process for Medium-Sized Cities in Developing Countries: Innovative Decision Support Framework for Sustainability
by Natthapoj Faiboun, Pongrid Klungboonkrong, Rungsun Udomsri and Sittha Jaensirisak
Sustainability 2024, 16(11), 4731; https://doi.org/10.3390/su16114731 (registering DOI) - 1 Jun 2024
Abstract
The challenges resulting from rapid economic growth, urbanization, and increased motorization in developing nations necessitate a comprehensive and sustainable approach to urban public transport planning. While sustainable urban public transport (SUPT) planning offers a solution, the complexity of choosing suitable policy measure options [...] Read more.
The challenges resulting from rapid economic growth, urbanization, and increased motorization in developing nations necessitate a comprehensive and sustainable approach to urban public transport planning. While sustainable urban public transport (SUPT) planning offers a solution, the complexity of choosing suitable policy measure options remains a challenge. This study first introduces a decision support framework (DSF) that integrates the sustainable urban public transport manual (SUPTM) adopted for generating the potential SUPT policy measure options, the KonSULT knowledge base applied for providing the performance scores of each measure option for all determined criteria, and the HMADM (including FAHP, FSM, and TOPSIS) technique to create, rank, and select SUPT policy measure options tailored to medium-sized urban areas in developing nations. A case study of Khon Kaen City, Thailand, illustrates the practical application of the framework, resulting in a set of 31 (91.2%) out of the total of 34 ranked policy measure options. Comparing these prioritizations with the city’s existing plan reveals a substantial agreement, which suggests the potential applicability of the DSF. Overall, the DSF marks a significant advancement in SUPT planning, which is crucial for shaping efficient, equitable, and environmentally conscious urban mobility in developing countries, which are undergoing transformative change. Full article
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17 pages, 3640 KiB  
Article
One Step beyond Species Description: Unveiling a Fine-Scale Diversity within the Genus Dzhanokmenia Kostjukov (Hymenoptera: Eulophidae)
by Bolormaa Ganbaatar, Qin Li, Ouyan Xi, Huanxi Cao and Chaodong Zhu
Insects 2024, 15(6), 406; https://doi.org/10.3390/insects15060406 (registering DOI) - 1 Jun 2024
Abstract
Although Chalcidoidea is one of the megadiverse superfamilies in Hymenoptera, numerous species are still being discovered and described. However, the difficulties in delimiting intra- and interspecific variation hinder this process. In this study, DNA barcoding methods using the COI gene were employed to [...] Read more.
Although Chalcidoidea is one of the megadiverse superfamilies in Hymenoptera, numerous species are still being discovered and described. However, the difficulties in delimiting intra- and interspecific variation hinder this process. In this study, DNA barcoding methods using the COI gene were employed to investigate the morphological variation within Dzhanokmenia Kostjukov, 1977. The nuclear locus, 28S D2, was used to infer a phylogeny to gain an understanding of the relationship of Dzhanokmenia with other potentially close genera. Through a preliminary DNA barcode library established here, including eight species, we calibrated the intraspecific variation in certain diagnostic characters for the new species described here, D. brevifunis Ganbaatar & Cao sp. nov. Maximum likelihood results show that Dzhanokmenia is clustered with the genera associated with Tetrastichus, such as Chaenotetrastichus Graham, 1987, Baryscapus Förster, 1856, Tetrastichus Haliday, 1844, and Oomyzus Rondani, 1870 involved in this study. Our results indicate that the species diversity of Dzhanokmenia is understudied and tentatively confirm that Dzhanokmenia has a potential close relationship with Baryscapus. Along with the DNA barcode library, the referenced phylogeny datasets improve the understanding of the systematic position of Dzhanokmenia within the subfamily Tetrastichinae and the definition of this genus in terms of morphology, thereby facilitating species delimitation, discovery, and description within Dzhanokmenia. Full article
(This article belongs to the Collection Hymenoptera: Biology, Taxonomy and Integrated Management)
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14 pages, 3256 KiB  
Article
Preparation and Characterization of Novel Multifunctional Wound Dressing by Near-Field Direct-Writing Electrospinning and Its Application
by Dingfan Li, Dongsong Lin, Yun Li, Sikun Xu, Qingyun Cao and Wuyi Zhou
Polymers 2024, 16(11), 1573; https://doi.org/10.3390/polym16111573 (registering DOI) - 1 Jun 2024
Abstract
Near-field direct-writing electrospinning technology can be used to produce ordered micro/nanofiber membrane dressings. The application of this technology can simply realize the control of dressing porosity, compound different functional substances, and adjust their distribution, thus improving the defects of common dressings such as [...] Read more.
Near-field direct-writing electrospinning technology can be used to produce ordered micro/nanofiber membrane dressings. The application of this technology can simply realize the control of dressing porosity, compound different functional substances, and adjust their distribution, thus improving the defects of common dressings such as insufficient breathability, poor moisture retention performance, and single function. Herein, a novel multifunctional wound dressing was prepared to utilize near-field direct-writing electrospinning technology, in which calf skin collagen type I (CSC-I) and polycaprolactone (PCL) were used as the composite matrix, Hexafluoroisopropanol (HFIP) as the solvent, and erythromycin (ERY) as an anti-infective drug component. The results show that the micro/nanofiber membranes prepared by near-field direct-writing electrospinning technology can all present a complete mesh structure, excellent thermal stability, and good moisturizing properties. Moreover, the composite fiber membrane loaded with ERY not only had obvious antibacterial properties against E. coli and S. thermophilus but also a better slow-release function of drugs (it is rare to have both in traditional wound dressings). Therefore, this experimental design can provide relevant theories and an experimental foundation for preparing a new type of medical dressing with drug loading and has good guiding significance for the application and promotion of near-field direct-writing electrospinning in medical dressings. Full article
(This article belongs to the Section Smart and Functional Polymers)
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16 pages, 13205 KiB  
Article
The Effect of Heat Treatment on the Microstructure and Mechanical Properties of Powder Metallurgy Ti-48Al Alloy
by Mengjie Yan, Hongtao Zhang, Fang Yang, Yunwei Gui, Zhijie Han and Huadong Fu
Metals 2024, 14(6), 661; https://doi.org/10.3390/met14060661 (registering DOI) - 1 Jun 2024
Abstract
Heat treatment is the critical step in achieving a refined microstructure and enhanced mechanical properties of TiAl-based alloys. This study investigated the influence of heat treatment temperature, cooling method, and heat treatment time on the microstructure and mechanical properties of an extruded powder [...] Read more.
Heat treatment is the critical step in achieving a refined microstructure and enhanced mechanical properties of TiAl-based alloys. This study investigated the influence of heat treatment temperature, cooling method, and heat treatment time on the microstructure and mechanical properties of an extruded powder metallurgy Ti-48Al alloy, and achieved the control of fully lamellar fine microstructures and the enhancement of performance through a simple heat treatment, rather than the traditional approach of homogenization followed by heat treatment. The results indicate that the heat treatment temperature determines the type of microstructure, while the cooling rate dictates the lamellar width. As the heat treatment temperature was increased from the two-phase region to the α single-phase region, the microstructure transitioned from duplex to near lamellar, and the alloy strength initially increased and then decreased, influenced by both the lamellar colony ratio and grain size. A rapid cooling rate (water quenching) induces a non-diffusive massive phase transformation, whereas a slow cooling rate (air cooling) gradually forms α2/γ lamellar colonies. Therefore, a suitable heat treatment regime for the powder metallurgy Ti-48Al alloy was determined to be 1340 °C/5 min/air cooling. The microstructure of the alloy was near lamellar, consisting of lamellar colonies approximately 50 μm and a small number of γ equiaxed grains of about 10 μm. Subsequently, the alloy exhibited a room temperature tensile strength of 784 MPa and a yield strength of 763 MPa, representing improvements of 17.0% and 38.7% over the extruded alloy, respectively. This research provides a reference for establishing a heat treatment process for powder metallurgy TiAl alloys. Full article
(This article belongs to the Special Issue Advances in Powder Metallurgy of Light Alloys)
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11 pages, 5044 KiB  
Article
Mo-Doped Na4Fe3(PO4)2P2O7/C Composites for High-Rate and Long-Life Sodium-Ion Batteries
by Tongtong Chen, Xianying Han, Mengling Jie, Zhiwu Guo, Jiangang Li and Xiangming He
Materials 2024, 17(11), 2679; https://doi.org/10.3390/ma17112679 (registering DOI) - 1 Jun 2024
Abstract
Na4Fe3(PO4)2P2O7/C (NFPP) is a promising cathode material for sodium-ion batteries, but its electrochemical performance is heavily impeded by its low electronic conductivity. To address this, pure-phase Mo6+-doped Na4 [...] Read more.
Na4Fe3(PO4)2P2O7/C (NFPP) is a promising cathode material for sodium-ion batteries, but its electrochemical performance is heavily impeded by its low electronic conductivity. To address this, pure-phase Mo6+-doped Na4Fe3−xMox(PO4)2P2O7/C (Mox-NFPP, x = 0, 0.05, 0.10, 0.15) with the Pn21a space group is successfully synthesized through spray drying and annealing methods. Density functional theory (DFT) calculations reveal that Mo6+ doping facilitates the transition of electrons from the valence to the conduction band, thus enhancing the intrinsic electron conductivity of Mox-NFPP. With an optimal Mo6+ doping level of x = 0.10, Mo0.10-NFPP exhibits lower charge transfer resistance, higher sodium-ion diffusion coefficients, and superior rate performance. As a result, the Mo0.10-NFPP cathode offers an initial discharge capacity of up to 123.9 mAh g−1 at 0.1 C, nearly reaching its theoretical capacity. Even at a high rate of 10 C, it delivers a high discharge capacity of 86.09 mAh g−1, maintaining 96.18% of its capacity after 500 cycles. This research presents a new and straightforward strategy to enhance the electrochemical performance of NFPP cathode materials for sodium-ion batteries. Full article
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12 pages, 2553 KiB  
Article
Stability Analysis of “321” Prefabricated Highway Steel Truss Bridge
by Haifang He, Yulong Zhou, Shoushan Cheng, Ning An, Hongyi Liu and Zhixuan Fei
Buildings 2024, 14(6), 1626; https://doi.org/10.3390/buildings14061626 (registering DOI) - 1 Jun 2024
Abstract
The “321” prefabricated highway steel truss bridge is widely used for highway rescue, disaster relief, and emergency traffic. This paper uses a 33 m double-row monolayer “321” prefabricated highway steel truss bridge to analyze its mechanical properties and component stability. The actual traffic [...] Read more.
The “321” prefabricated highway steel truss bridge is widely used for highway rescue, disaster relief, and emergency traffic. This paper uses a 33 m double-row monolayer “321” prefabricated highway steel truss bridge to analyze its mechanical properties and component stability. The actual traffic flow capacity of a total weight of 53.32 tons is used in this study. The results show that the maximum internal force in the truss chord (including the stiffening chord) occurs in the middle span section when a centrally distributed load is applied. Meanwhile, the maximum internal force of truss diagonal members and truss vertical bars appears at the fulcrum section. Under the eccentrically distributed load, the maximum internal forces of truss chords (including stiffening chords) appear in the middle span section, which is closest to the vehicle load, while the maximum internal forces of truss diagonal members and truss vertical bars appear in the fulcrum section, which is closest to the vehicle load. While the maximum internal forces under the eccentrically distributed load are greater than the maximum internal forces under the centered-layout load, under the vehicle load, truss chords (including stiffening chords) are prone to buckling instability, and the buckling mode is mainly reverse out-of-plane buckling. The inclined members of the truss are prone to buckling instability, and the buckling mode is mainly the combination of out-of-plane bending and two-way out-of-plane bending. Truss vertical bars have good stability and are not easy to buckle. The main conclusions of this paper can provide references for the optimal design and operation safety of prefabricated highway steel truss bridges. Full article
(This article belongs to the Special Issue Mechanical Performance of Steel and Composite Beams)
17 pages, 5764 KiB  
Review
Far-Field Super-Resolution Microscopy Using Evanescent Illumination: A Review
by Qianwei Zhang, Haonan Zhang, Xiaoyu Yang, Xu Liu, Mingwei Tang and Qing Yang
Photonics 2024, 11(6), 528; https://doi.org/10.3390/photonics11060528 (registering DOI) - 1 Jun 2024
Abstract
The resolution of conventional optical microscopy is restricted by the diffraction limit. Light waves containing higher-frequency information about the sample are bound to the sample surface and cannot be collected by far-field optical microscopy. To break the resolution limit, researchers have proposed various [...] Read more.
The resolution of conventional optical microscopy is restricted by the diffraction limit. Light waves containing higher-frequency information about the sample are bound to the sample surface and cannot be collected by far-field optical microscopy. To break the resolution limit, researchers have proposed various far-field super-resolution (SR) microscopy imaging methods using evanescent waves to transfer the high-frequency information of samples to the low-frequency passband of optical microscopy. Optimization algorithms are developed to reconstruct a SR image of the sample by utilizing the high-frequency information. These techniques can be collectively referred to as spatial-frequency-shift (SFS) SR microscopy. This review aims to summarize the basic principle of SR microscopy using evanescent illumination and introduce the advances in this research area. Some current challenges and possible directions are also discussed. Full article
(This article belongs to the Special Issue Super Resolution Optical Microscopy: Sensing and Imaging)
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19 pages, 3812 KiB  
Article
Evaluation and Spatial–Temporal Pattern Evolution of Synergy Degree of Emergency Management for Urban Flood Disasters from the Perspective of Sustainable Development—The Case of Henan, China
by Yu Hao, Chen Wang, Chaolun Sun and Delin Liu
Sustainability 2024, 16(11), 4730; https://doi.org/10.3390/su16114730 (registering DOI) - 1 Jun 2024
Abstract
The management of urban flood disasters is a systematic engineering project that requires a great amount of manpower, material resources, and financial resources, and the interaction and coordination degrees of various elements in the system deeply affect the efficiency of the final governance. [...] Read more.
The management of urban flood disasters is a systematic engineering project that requires a great amount of manpower, material resources, and financial resources, and the interaction and coordination degrees of various elements in the system deeply affect the efficiency of the final governance. According to the theories of synergy, composite systems, and sustainable development, this research first established an evaluation index system to determine the synergy degree of urban flood disaster emergency management from the four dimensions of prevention and preparation, monitoring and early warning, response and rescue, and recovery and reconstruction. Then, the synergy degree was explored by using the developed composite system synergy degree model on the basis of the panel data of 18 prefecture-level cities in Henan Province from 2013 to 2021, and synergy level change characteristics were analyzed from the perspectives of time and space. Finally, the obstacle degree model was applied to explore the obstacle factors affecting synergy degree development. The results showed that the overall level of the urban flood disaster emergency management coordination degree in Henan Province was relatively low, and there were significant differences in synergy among cities. Among them, 12 cities presented mild synergy, and 6 cities showed mild nonsynergy. The spatial correlation of the synergy degree was not stable, which revealed a lack of mature coordination mechanisms for flood disaster emergency management among cities. The analysis of obstacle factors showed that recovery and reconstruction subsystems were the main obstacle systems that affected the synergy degree. Full article
(This article belongs to the Section Environmental Sustainability and Applications)
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16 pages, 3573 KiB  
Article
Effect of A Moringa Oil–Beeswax Edible Coating on the Shelf-Life and Quality of Fresh Cucumber
by Shekha Al-Rashdi, Nusaiba Al-Subhi, Mai Al-Dairi and Pankaj B. Pathare
Processes 2024, 12(6), 1148; https://doi.org/10.3390/pr12061148 (registering DOI) - 1 Jun 2024
Abstract
Cucumbers are a popular vegetable consumed worldwide and are known for their nutritional value, containing carbohydrates, antioxidants, vitamin C, etc. The abundance of a high moisture content is correlated to cucumber perishability, which encourages investigation into ways to maintain its quality and increase [...] Read more.
Cucumbers are a popular vegetable consumed worldwide and are known for their nutritional value, containing carbohydrates, antioxidants, vitamin C, etc. The abundance of a high moisture content is correlated to cucumber perishability, which encourages investigation into ways to maintain its quality and increase shelf-life. This study was carried out to determine the effect of a moringa oil–beeswax coating on the quality of fresh cucumber at different storage temperatures for 27 days of storage. Freshly harvested cucumbers were divided into two groups: the first group was coated with the moringa oil–beeswax edible coating, while the other one was not coated (control). Each group was divided into three other subgroups, for storage at 4, 10, and 22 °C. Different quality parameters, including weight loss, color change, firmness, total soluble solid (TSS), vitamin C, and pH, were evaluated. The findings showed that the weight loss of cucumber was highly increased in non-coated samples stored at high temperature. After 27 days of storage, the highest and lowest weight reduction % were recorded for non-coated cucumbers stored at 22 °C (38.09%) and moringa oil–beeswax-coated cucumbers stored at 10 °C (12.35%), respectively. Color analysis revealed that coating had a significant impact on color values, with distinct patterns in lightness, redness-greenness, and yellowness values for both treatments at various temperatures and days. The lightness values showed minimal fluctuations and stabilized at 13.65 at both 4 °C and 10 °C. Temperature and coating had a significant impact on pH levels, with the coating potentially exhibiting a protective effect on pH stability, particularly at lower temperatures (4 °C). Additionally, both groups’ total acidity levels held steady over time and at various temperatures, with the coating having a highly significant effect on total acidity levels. The amount of vitamin C varied significantly with temperature and storage period, but the coating did not affect vitamin C content. At 22 °C, there were notable variations in the vitamin C content over the storage period, with a final value of 37.7 mg/L on coated samples. Temperature and the duration of storage (p < 0.05) had a significant impact on the levels of total soluble solids (TSS), whereas firmness values changed significantly over the storage period only. Moringa oil–beeswax edible coating has the potential to preserve the nutritional value and quality attributes of cucumber. Full article
(This article belongs to the Section Food Process Engineering)
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37 pages, 21313 KiB  
Review
Shape-Memory Polymers Based on Carbon Nanotube Composites
by Mariana Martins da Silva, Mariana Paiva Proença, José António Covas and Maria C. Paiva
Micromachines 2024, 15(6), 748; https://doi.org/10.3390/mi15060748 (registering DOI) - 1 Jun 2024
Abstract
For the past two decades, researchers have been exploring the potential benefits of combining shape-memory polymers (SMP) with carbon nanotubes (CNT). By incorporating CNT as reinforcement in SMP, they have aimed to enhance the mechanical properties and improve shape fixity. However, the remarkable [...] Read more.
For the past two decades, researchers have been exploring the potential benefits of combining shape-memory polymers (SMP) with carbon nanotubes (CNT). By incorporating CNT as reinforcement in SMP, they have aimed to enhance the mechanical properties and improve shape fixity. However, the remarkable intrinsic properties of CNT have also opened up new paths for actuation mechanisms, including electro- and photo-thermal responses. This opens up possibilities for developing soft actuators that could lead to technological advancements in areas such as tissue engineering and soft robotics. SMP/CNT composites offer numerous advantages, including fast actuation, remote control, performance in challenging environments, complex shape deformations, and multifunctionality. This review provides an in-depth overview of the research conducted over the past few years on the production of SMP/CNT composites with both thermoset and thermoplastic matrices, with a focus on the unique contributions of CNT to the nanocomposite’s response to external stimuli. Full article
(This article belongs to the Special Issue Feature Papers of Micromachines in 'Materials and Processing' 2024)
20 pages, 10766 KiB  
Article
Towards Sustainable Urban Mobility: Voronoi-Based Spatial Analysis of EV Charging Stations in Bangkok
by Sornkitja Boonprong, Nathapat Punturasan, Pariwate Varnakovida and Wichien Prechathamwong
Sustainability 2024, 16(11), 4729; https://doi.org/10.3390/su16114729 (registering DOI) - 1 Jun 2024
Abstract
This study leverages the efficacy of Voronoi diagram theory within a mixed-methods approach to thoroughly examine the spatial distribution, service coverage, and optimal locations for expanding electric vehicle (EV) charging infrastructure in Bangkok. Drawing on data from field surveys and public data providers, [...] Read more.
This study leverages the efficacy of Voronoi diagram theory within a mixed-methods approach to thoroughly examine the spatial distribution, service coverage, and optimal locations for expanding electric vehicle (EV) charging infrastructure in Bangkok. Drawing on data from field surveys and public data providers, our analysis unfolds in four key stages. Firstly, we delve into the spatial distribution of charging stations, scrutinizing density, proximity to various road types, and land use through the lens of Voronoi diagrams. Secondly, the application of Voronoi diagrams informs the evaluation of service boundaries. Thirdly, utilizing this effective tool, we assess population density per parking slot or charging head to anticipate future EV adoption. Finally, the study introduces an approach to identify suitable locations for new charging stations through the application of overlapping Voronoi circles. Findings reveal a clustered distribution of charging stations along roads, particularly in the central business district, showcasing the efficiency of Voronoi diagrams in spatial analysis. Residential areas and urban commercial zones also host significant charging station concentrations. Notably, service coverage in inner Bangkok surpasses that of middle and outer areas, highlighting underserved regions. Prospective areas for new charging stations, identified through Voronoi analysis, include Bang Khae, Phra Khanong, Min Buri, and Huai Khwang. This research, rooted in the application of Voronoi diagram theory, offers vital insights for various stakeholders involved in urban infrastructure planning. By employing Voronoi diagrams within Geographic Information Systems (GIS), the study contributes to strategically placing charging stations, optimizing spatial understanding, and enhancing resource allocation. This GIS-based approach not only supports the rise of electric vehicles but also promotes sustainable urban development practices through the efficient utilization of spatial data and analysis techniques. Full article
(This article belongs to the Special Issue Towards Sustainable Urban Transport System)
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21 pages, 1444 KiB  
Review
Comprehensive Overview of Broadly Neutralizing Antibodies against SARS-CoV-2 Variants
by Lingyan Cui, Tingting Li, Wenhui Xue, Sibo Zhang, Hong Wang, Hongjing Liu, Ying Gu, Ningshao Xia and Shaowei Li
Viruses 2024, 16(6), 900; https://doi.org/10.3390/v16060900 (registering DOI) - 1 Jun 2024
Abstract
Currently, SARS-CoV-2 has evolved into various variants, including the numerous highly mutated Omicron sub-lineages, significantly increasing immune evasion ability. The development raises concerns about the possibly diminished effectiveness of available vaccines and antibody-based therapeutics. Here, we describe those representative categories of broadly neutralizing [...] Read more.
Currently, SARS-CoV-2 has evolved into various variants, including the numerous highly mutated Omicron sub-lineages, significantly increasing immune evasion ability. The development raises concerns about the possibly diminished effectiveness of available vaccines and antibody-based therapeutics. Here, we describe those representative categories of broadly neutralizing antibodies (bnAbs) that retain prominent effectiveness against emerging variants including Omicron sub-lineages. The molecular characteristics, epitope conservation, and resistance mechanisms of these antibodies are further detailed, aiming to offer suggestion or direction for the development of therapeutic antibodies, and facilitate the design of vaccines with broad-spectrum potential. Full article
(This article belongs to the Special Issue SARS-CoV-2 Neutralizing Antibodies 2.0)
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17 pages, 2719 KiB  
Article
Quantitative Assessment of Volcanic Thermal Activity from Space Using an Isolation Forest Machine Learning Algorithm
by Claudia Corradino, Arianna Beatrice Malaguti, Micheal S. Ramsey and Ciro Del Negro
Remote Sens. 2024, 16(11), 2001; https://doi.org/10.3390/rs16112001 (registering DOI) - 1 Jun 2024
Abstract
Understanding the dynamics of volcanic activity is crucial for volcano observatories in their efforts to forecast volcanic hazards. Satellite imager data hold promise in offering crucial insights into the thermal behavior of active volcanoes worldwide, facilitating the assessment of volcanic activity levels and [...] Read more.
Understanding the dynamics of volcanic activity is crucial for volcano observatories in their efforts to forecast volcanic hazards. Satellite imager data hold promise in offering crucial insights into the thermal behavior of active volcanoes worldwide, facilitating the assessment of volcanic activity levels and identifying significant changes during periods of volcano unrest. The Moderate Resolution Imaging Spectroradiometer (MODIS) sensor, aboard NASA’s Terra and Aqua satellites, provides invaluable data with high temporal and spectral resolution, enabling comprehensive thermal monitoring of eruptive activity. The accuracy of volcanic activity characterization depends on the quality of models used to relate the relationship between volcanic phenomena and target variables such as temperature. Under these circumstances, machine learning (ML) techniques such as decision trees can be employed to develop reliable models without necessarily offering any particular or explicit insights. Here, we present a ML approach for quantifying volcanic thermal activity levels in near real time using thermal infrared satellite data. We develop an unsupervised Isolation Forest machine learning algorithm, fully implemented in Google Colab using Google Earth Engine (GEE) which utilizes MODIS Land Surface Temperature (LST) data to automatically retrieve information on the thermal state of volcanoes. We evaluate the algorithm on various volcanoes worldwide characterized by different levels of volcanic activity. Full article
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13 pages, 2828 KiB  
Article
Catha edulis Leaves: Morphological Characterization and Anti-Inflammatory Properties in an In Vitro Model of Gastritis
by Andrea Magnavacca, Claudia Giuliani, Gabriella Roda, Stefano Piazza, Giulia Martinelli, Carola Pozzoli, Nicole Maranta, Alessio Papini, Martina Bottoni, Eleonora Casagni, Michele Dei Cas, Gelsomina Fico, Mario Dell’Agli and Enrico Sangiovanni
Plants 2024, 13(11), 1538; https://doi.org/10.3390/plants13111538 (registering DOI) - 1 Jun 2024
Abstract
Khat leaves, indigenous to eastern Africa, have been chewed for centuries for their stimulant effects, attributed to alkaloids such as cathinone and cathine. Although associated with gastric disorders like gastritis and gastro-oesophageal reflux disease, the underlying molecular mechanisms remain unclear. This study aimed [...] Read more.
Khat leaves, indigenous to eastern Africa, have been chewed for centuries for their stimulant effects, attributed to alkaloids such as cathinone and cathine. Although associated with gastric disorders like gastritis and gastro-oesophageal reflux disease, the underlying molecular mechanisms remain unclear. This study aimed to examine the morpho-anatomy of khat leaves using light microscopy and histochemistry and to assess the effects of leaf extracts and alkaloids on human gastric epithelial cells (GES-1). The study identified specific cells in the palisade–spongy transition zone as storage sites for psychoactive alkaloids. Leaf extracts were prepared by mimicking the chewing process, including a prolonged salivary phase followed by a gastric phase. Cytotoxicity and cell viability were evaluated using LDH and MTT assays, respectively. Additionally, the impact on IL-8 secretion, a key chemokine in gastric inflammation, was analysed under normal and TNF-α-stimulated conditions. The results showed no increase in cytotoxicity up to 250 µg/mL. However, there was a significant decrease in cell metabolism and a reduction in both basal and TNF-α-induced IL-8 secretion, but cathinone and cathine were inactive. These findings suggest that khat may not directly cause the gastric issues reported in the literature, which would rather be attributed to other confounding factors, highlighting the need for further research to clarify its biological impacts. Full article
(This article belongs to the Section Phytochemistry)
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34 pages, 6069 KiB  
Article
Development of a Predictive Model for Evaluation of the Influence of Various Parameters on the Performance of an Oscillating Water Column Device
by Felice Sfravara, Emmanuele Barberi, Giacomo Bongiovanni, Massimiliano Chillemi and Sebastian Brusca
Sensors 2024, 24(11), 3582; https://doi.org/10.3390/s24113582 (registering DOI) - 1 Jun 2024
Abstract
Oscillating Water Column (OWC) systems harness wave energy using a partially submerged chamber with an underwater opening. The Savonius turbine, a vertical-axis wind turbine, is well-suited for this purpose due to its efficiency at low speeds and self-starting capability, making it an ideal [...] Read more.
Oscillating Water Column (OWC) systems harness wave energy using a partially submerged chamber with an underwater opening. The Savonius turbine, a vertical-axis wind turbine, is well-suited for this purpose due to its efficiency at low speeds and self-starting capability, making it an ideal power take-off (PTO) mechanism in OWC systems. This study tested an OWC device with a Savonius turbine in an air duct to evaluate its performance under varying flow directions and loads. An innovative aspect was assessing the influence of power augmenters (PAs) positioned upstream and downstream of the turbine. The experimental setup included load cells, Pitot tubes, differential pressure sensors and rotational speed sensors. Data obtained were used to calculate pressure differentials across the turbine and torque. The primary goal of using PA is to increase the CP–λ curve area without modifying the turbine geometry, potentially enabling interventions on existing turbines without rotor dismantling. Additionally, another novelty is the implementation of a regression Machine-Learning algorithm based on decision trees to analyze the influence of various features on predicting pressure differences, thereby broadening the scope for further testing beyond physical experimentation. Full article
(This article belongs to the Special Issue Real-Time Monitoring Technology for Built Infrastructure Systems)
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26 pages, 21469 KiB  
Article
Analysis of Amplification Effect and Optimal Control of the Toggle-Style Negative Stiffness Viscous Damper
by Qiang Zhou, Wen Pan and Xiang Lan
Buildings 2024, 14(6), 1625; https://doi.org/10.3390/buildings14061625 (registering DOI) - 1 Jun 2024
Abstract
This paper proposes a new toggle-style negative stiffness viscous damper (TNVD), and evaluates the performance of the TNVD with the displacement amplification factor (fd) and the energy dissipation factor (fE). Firstly, the composition and characteristics of the [...] Read more.
This paper proposes a new toggle-style negative stiffness viscous damper (TNVD), and evaluates the performance of the TNVD with the displacement amplification factor (fd) and the energy dissipation factor (fE). Firstly, the composition and characteristics of the TNVD are introduced. Subsequently, the displacement amplification factor is introduced to evaluate the displacement amplification ability of the TNVD, and it is decomposed into a geometric amplification factor and an effective displacement coefficient. Then, based on the geometric amplification factor and effective displacement coefficient, the correlation between the TNVD’s displacement amplification ability and inter-story deformation is studied, and an improved TNVD is proposed. By the comparison of the finite element calculation results, it is found that the improved TNVD can utilize the assumption of small structural deformation. After that, the impacts of plentiful aspects, such as the length of the lower connecting rod, the horizontal inclination angle of the lower connecting rod, the inter-story deformation limit, the cross-sectional area of the connecting rod, the damping coefficient, and the negative stiffness on the fd and fE of the improved TNVD, are expounded. The research results show that when the length of the TNVD’s lower connecting rod remains unchanged, the fd and fE present a trend of increasing first and then decreasing with the increase in the horizontal inclination angle of the lower connecting rod. When the inter-story deformation is fixed, there exists an optimal lower connecting rod’s length that satisfies a specific relationship to achieve the optimal geometric amplification factor of the TNVD. By adjusting the damping parameters of the TNVD, we can obtain a better effective displacement coefficient greater than 0.95 in the proposed target region. Meanwhile, the fd and fE increase with the decrease in the negative stiffness. An optimization strategy for the improved TNVD has been proposed to ensure that the TNVD has the characteristics of operational safety, ideal displacement amplification capability, and energy dissipation capability. Furthermore, a multi-objective control design method with an additional improved TNVD structure is proposed. The vibration reduction effect of the structure with the improved TNVD and the effectiveness of the optimization strategy are verified through examples. Full article
(This article belongs to the Special Issue Advances and Applications in Structural Vibration Control)
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14 pages, 3457 KiB  
Article
Forecasting and Mapping the Environmental and Health Impacts of Sustainable Regional Transport Policies
by Rita Prior Filipe, Andrew Heath, Nick McCullen and Theresa Smith
Sustainability 2024, 16(11), 4728; https://doi.org/10.3390/su16114728 (registering DOI) - 1 Jun 2024
Abstract
Research on evaluating sustainable transport policies is predominantly focused on their urban effects, often overlooking similar challenges in suburban and rural mobility. Therefore, the development of regionally integrated sustainable transport strategies becomes essential to comprehensively address these concerns. This study aims to bridge [...] Read more.
Research on evaluating sustainable transport policies is predominantly focused on their urban effects, often overlooking similar challenges in suburban and rural mobility. Therefore, the development of regionally integrated sustainable transport strategies becomes essential to comprehensively address these concerns. This study aims to bridge this gap by introducing a GIS-supported methodology that combines multiple linear regressions with hazard ratio models to quantify and map the impacts of environmentally driven regional transport policies on air pollution and human health. The main findings of an illustrative case study highlighted the importance of stronger efforts to promote the transition to shared and active transport and address the articulation between urban and rural mobility. This study offers a novel contribution to transport researchers and policymakers by proposing a methodology that (1) forecasts the impacts of regional transport policies using open data and software, ensuring its applicability for diverse regional settings, (2) provides the results in quantitative and visual formats, facilitating output analysis and visualisation and, consequently, decision-making and public consultation on proposed sustainable transport policies, and (3) sets the groundwork for including future transport-related dimensions. Full article
(This article belongs to the Section Sustainable Transportation)
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19 pages, 3699 KiB  
Article
In Vitro Cell Culture Model for Osteoclast Activation during Estrogen Withdrawal
by Nisha Gandhi, Safia Omer and Rene E. Harrison
Int. J. Mol. Sci. 2024, 25(11), 6134; https://doi.org/10.3390/ijms25116134 (registering DOI) - 1 Jun 2024
Abstract
Estrogen (17β-estradiol) deficiency post-menopause alters bone homeostasis whereby bone resorption by osteoclasts exceeds bone formation by osteoblasts, leading to osteoporosis in females. We established an in vitro model to examine the consequences of estrogen withdrawal (E2-WD) on osteoclasts derived from the mouse macrophage [...] Read more.
Estrogen (17β-estradiol) deficiency post-menopause alters bone homeostasis whereby bone resorption by osteoclasts exceeds bone formation by osteoblasts, leading to osteoporosis in females. We established an in vitro model to examine the consequences of estrogen withdrawal (E2-WD) on osteoclasts derived from the mouse macrophage RAW 264.7 cell line and utilized it to investigate the mechanism behind the enhanced osteoclast activity post-menopause. We found that a greater population of osteoclasts that underwent E2-WD contained a podosome belt necessary for osteoclasts to adhere and resorb bone and possessed elevated resorptive activity compared to osteoclasts exposed to estrogen (E2) continuously. Our results show that compared to osteoclasts that received E2 continuously, those that underwent E2-WD had a faster rate of microtubule (MT) growth, reduced RhoA activation, and shorter podosome lifespan. Thus, altered podosome and MT dynamics induced by the withdrawal of estrogen supports podosome belt assembly/stability in osteoclasts, which may explain their enhanced bone resorption activity. Full article
(This article belongs to the Section Molecular Biology)
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14 pages, 6900 KiB  
Article
Algae Derived Carbon from Hydrothermal Liquefaction as Sustainable Carbon Electrode Material for Supercapacitor
by Kingsford Asare, Abhijeet Mali, Md Faruque Hasan, Philip Agbo, Abolghasem Shahbazi and Lifeng Zhang
C 2024, 10(2), 51; https://doi.org/10.3390/c10020051 (registering DOI) - 1 Jun 2024
Abstract
With the worldwide awareness of sustainability, biomass-derived carbon electrode materials for supercapacitors have attracted growing attention. In this research, for the first time, we explored the feasibility of making use of the carbon byproduct from hydrothermal liquefaction (HTL) of microalgae, termed herein as [...] Read more.
With the worldwide awareness of sustainability, biomass-derived carbon electrode materials for supercapacitors have attracted growing attention. In this research, for the first time, we explored the feasibility of making use of the carbon byproduct from hydrothermal liquefaction (HTL) of microalgae, termed herein as algae-derived carbon (ADC), to prepare sustainable carbon electrode materials for high-performance supercapacitor development. Specifically, we investigated carbon activation with a variety of activating reagents as well as N- and Fe-doping of the obtained ADC with the intention to enhance its electrochemical performance. We characterized the structure of the activated and doped ADCs using scanning electron microscope (SEM), Raman spectroscopy, Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), and BET surface area and pore analysis, and correlated the ADCs’ structure with their electrochemical performance as evaluated using cyclic voltammetry (CV), galvanostatic charge/discharge (GCD), impedance, and cycle stability through an assembled symmetric two-electrode cell with 1 M H2SO4 as electrolyte. It was found that the ADC that is activated using KOH (KOH-ADC) showed the best electrochemical performance, and its specific capacitance was 14.1-fold larger with respect to that of the raw ADC and reached 234.5 F/g in the GCD test at a current density of 0.5 A/g. The KOH-ADC also demonstrated excellent capacitance retention (97% after 10,000 cycles at a high current density of 10 A/g) for stable long-term operations. This research pointed out a promising direction to develop sustainable electrode materials for supercapacitors from the carbon byproduct produced after HTL processing of algae. Full article
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16 pages, 16286 KiB  
Article
AMELX Mutations and Genotype–Phenotype Correlation in X-Linked Amelogenesis Imperfecta
by Shih-Kai Wang, Hong Zhang, Hua-Chieh Lin, Yin-Lin Wang, Shu-Chun Lin, Figen Seymen, Mine Koruyucu, James P. Simmer and Jan C.-C. Hu
Int. J. Mol. Sci. 2024, 25(11), 6132; https://doi.org/10.3390/ijms25116132 (registering DOI) - 1 Jun 2024
Abstract
AMELX mutations cause X-linked amelogenesis imperfecta (AI), known as AI types IE, IIB, and IIC in Witkop’s classification, characterized by hypoplastic (reduced thickness) and/or hypomaturation (reduced hardness) enamel defects. In this study, we conducted whole exome analyses to unravel the disease-causing mutations for [...] Read more.
AMELX mutations cause X-linked amelogenesis imperfecta (AI), known as AI types IE, IIB, and IIC in Witkop’s classification, characterized by hypoplastic (reduced thickness) and/or hypomaturation (reduced hardness) enamel defects. In this study, we conducted whole exome analyses to unravel the disease-causing mutations for six AI families. Splicing assays, immunoblotting, and quantitative RT-PCR were conducted to investigate the molecular and cellular effects of the mutations. Four AMELX pathogenic variants (NM_182680.1:c.2T>C; c.29T>C; c.77del; c.145-1G>A) and a whole gene deletion (NG_012494.2:g.307534_403773del) were identified. The affected individuals exhibited enamel malformations, ranging from thin, poorly mineralized enamel with a “snow-capped” appearance to severe hypoplastic defects with minimal enamel. The c.145-1G>A mutation caused a -1 frameshift (NP_001133.1:p.Val35Cysfs*5). Overexpression of c.2T>C and c.29T>C AMELX demonstrated that mutant amelogenin proteins failed to be secreted, causing elevated endoplasmic reticulum stress and potential cell apoptosis. This study reveals a genotype–phenotype relationship for AMELX-associated AI: While amorphic mutations, including large deletions and 5′ truncations, of AMELX cause hypoplastic-hypomaturation enamel with snow-capped teeth (AI types IIB and IIC) due to a complete loss of gene function, neomorphic variants, including signal peptide defects and 3′ truncations, lead to severe hypoplastic/aplastic enamel (AI type IE) probably caused by “toxic” cellular effects of the mutant proteins. Full article
(This article belongs to the Special Issue Molecular Metabolism of Ameloblasts in Tooth Development)
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