The 2023 MDPI Annual Report has
been released!
 
16 pages, 5204 KiB  
Article
Growth Rings in Nine Tree Species on a Neotropical Island with High Precipitation: Coco Island, Costa Rica
by Róger Moya, Carolina Tenorio and Luis Acosta-Vargas
Forests 2024, 15(5), 885; https://doi.org/10.3390/f15050885 (registering DOI) - 19 May 2024
Abstract
Coco Island, located 530 km off the Pacific coast of Costa Rica, experiences rainfall of over 7000 mm/year. This study aims to explore the distinctiveness of the growth ring boundaries and the dendrochronological potential (DP) of nine tree species found on Coco Island. [...] Read more.
Coco Island, located 530 km off the Pacific coast of Costa Rica, experiences rainfall of over 7000 mm/year. This study aims to explore the distinctiveness of the growth ring boundaries and the dendrochronological potential (DP) of nine tree species found on Coco Island. The distinctiveness was classified into type 1: density variation; type 2: marginal parenchyma; type 3: fiber/parenchyma pattern; type 4: vessel distribution, and type 5: fiber band. Cecropia pittieri and Henriettella fascicularis lacked growth ring boundaries and, therefore, did not present any DP. Growth ring type 1 occurred in Ardisia compressa, Henriettea succosa, Henriettella odorata, and Psychotria cocosensis. Ocotea insularis and Sacoglottis holdridgei exhibited type 5 growth rings, with sufficient distinctiveness. Finally, Eugenia pacifica possessed growth rings of type 3 and type 4, but with limited distinctiveness in the growth ring boundary. In relation to DP, A. compressa, E. pacifica, and P. cocosensis presented low DP; meanwhile, H. succosa, H. odorata, O. insularis, and S. holdridgei demonstrated medium DP. If these species are found in abundance with a diameter exceeding 60 cm, a cross-dating technique like bomb-spike dating is established to confirm the annual growth of the ‘bands’. As these species exhibit some DP, they can be used to establish a chronology spanning 50–130 years, which could be utilized to create climate proxies or derive ecologically and climatically meaningful information. Additionally, the information presented could pave the way for future studies of sites that also have very high rainfall, where trees are presumed to lack annual growth rings. Full article
(This article belongs to the Special Issue Effects of Climate Change on Tree-Ring Growth)
9 pages, 345 KiB  
Article
Risk Characterization of Firms with ESG Attributes Using a Supervised Machine Learning Method
by Prodosh Eugene Simlai
J. Risk Financial Manag. 2024, 17(5), 211; https://doi.org/10.3390/jrfm17050211 (registering DOI) - 19 May 2024
Abstract
We examine the risk–return tradeoff of a portfolio of firms that have tangible environmental, social, and governance (ESG) attributes. We introduce a new type of penalized regression using the Mahalanobis distance-based method and show its usefulness using our sample of ESG firms. Our [...] Read more.
We examine the risk–return tradeoff of a portfolio of firms that have tangible environmental, social, and governance (ESG) attributes. We introduce a new type of penalized regression using the Mahalanobis distance-based method and show its usefulness using our sample of ESG firms. Our results show that ESG companies are exposed to financial state variables that capture the changes in investment opportunities. However, we find that there is no economically significant difference between the risk-adjusted returns of various ESG-rating-based portfolios and that the risk associated with a poor ESG rating portfolio is not significantly different than that of a good ESG rating portfolio. Although investors require return compensation for holding ESG stocks, the fact that the risk of a poor ESG rating portfolio is comparable to that of a good ESG rating portfolio suggests risk dimensions that go beyond ESG attributes. We further show that the new covariance-adjusted penalized regression improves the out-of-sample cross-sectional predictions of the ESG portfolio's expected returns. Overall, our approach is pragmatic and based on the ease of an empirical appeal. Full article
(This article belongs to the Special Issue Financial Valuation and Econometrics)
30 pages, 4149 KiB  
Article
Camera-Based Crime Behavior Detection and Classification
by Jerry Gao, Jingwen Shi, Priyanka Balla, Akshata Sheshgiri, Bocheng Zhang, Hailong Yu and Yunyun Yang
Smart Cities 2024, 7(3), 1169-1198; https://doi.org/10.3390/smartcities7030050 (registering DOI) - 19 May 2024
Abstract
Increasing numbers of public and private locations now have surveillance cameras installed to make those areas more secure. Even though many organizations still hire someone to monitor the cameras, the person hired is more likely to miss some unexpected events in the video [...] Read more.
Increasing numbers of public and private locations now have surveillance cameras installed to make those areas more secure. Even though many organizations still hire someone to monitor the cameras, the person hired is more likely to miss some unexpected events in the video feeds because of human error. Several researchers have worked on surveillance data and have presented a number of approaches for automatically detecting aberrant events. To keep track of all the video data that accumulate, a supervisor is often required. To analyze the video data automatically, we recommend using neural networks to identify the crimes happening in the real world. Through our approach, it will be easier for police agencies to discover and assess criminal activity more quickly using our method, which will reduce the burden on their staff. In this paper, we aim to provide anomaly detection using surveillance videos as input specifically for the crimes of arson, burglary, stealing, and vandalism. It will provide an efficient and adaptable crime-detection system if integrated across the smart city infrastructure. In our project, we trained multiple accurate deep learning models for object detection and crime classification for arson, burglary and vandalism. For arson, the videos were trained using YOLOv5. Similarly for burglary and vandalism, we trained using YOLOv7 and YOLOv6, respectively. When the models were compared, YOLOv7 performed better with the highest mAP of 87. In this, we could not compare the model’s performance based on crime type because all the datasets for each crime type varied. So, for arson YOLOv5 performed well with 80% mAP and for vandalism, YOLOv6 performed well with 86% mAP. This paper designed an automatic identification of crime types based on camera or surveillance video in the absence of a monitoring person, and alerts registered users about crimes such as arson, burglary, and vandalism through an SMS service. To detect the object of the crime in the video, we trained five different machine learning models: Improved YOLOv5 for arson, Faster RCNN and YOLOv7 for burglary, and SSD MobileNet and YOLOv6 for vandalism. Other than improved models,we innovated by building ensemble models of all three crime types. The main aim of the project is to provide security to the society without human involvement and make affordable surveillance cameras to detect and classify crimes. In addition, we implemented the Web system design using the built package in Python, which is Gradio. This helps the registered user of the Twilio communication tool to receive alert messages when any suspicious activity happens around their communities. Full article
18 pages, 348 KiB  
Article
Driving Economic Growth through Transportation Infrastructure: An In-Depth Spatial Econometric Analysis
by Jianwei Shi, Tongyuan Bai, Zhihong Zhao and Huachun Tan
Sustainability 2024, 16(10), 4283; https://doi.org/10.3390/su16104283 (registering DOI) - 19 May 2024
Abstract
This research investigates the crucial role of transportation infrastructure in influencing economic activity, thus employing advanced econometric methods including Moran’s I index, LM, Hausman, and LR tests to ensure analytical accuracy and select the appropriate spatial model. Our findings reveal that freight volumes [...] Read more.
This research investigates the crucial role of transportation infrastructure in influencing economic activity, thus employing advanced econometric methods including Moran’s I index, LM, Hausman, and LR tests to ensure analytical accuracy and select the appropriate spatial model. Our findings reveal that freight volumes across road, waterway, and civil aviation significantly enhance economic activity by bolstering domestic trade, industrial production, and supply chains. Conversely, the impact of passenger turnover is comparatively minor, although it still contributes to labor mobility and urban accessibility. This study highlights the need for strategic investment in transportation infrastructure and efficient public transport systems to foster economic growth and sustainable development. We recommend that policymakers focus on optimizing transportation networks and integrating intelligent transport technologies to boost economic competitiveness and societal well-being. This analysis not only sheds light on the direct economic impacts of transportation but also underscores the broader social implications, thus advocating for a holistic approach to transportation planning and policymaking. Full article
20 pages, 2983 KiB  
Article
Three-Dimensional Bioprinting of GelMA Hydrogels with Culture Medium: Balancing Printability, Rheology and Cell Viability for Tissue Regeneration
by Laura Mendoza-Cerezo, Jesús M. Rodríguez-Rego, Antonio Macías-García, Antuca Callejas-Marín, Luís Sánchez-Guardado and Alfonso C. Marcos-Romero
Polymers 2024, 16(10), 1437; https://doi.org/10.3390/polym16101437 (registering DOI) - 19 May 2024
Abstract
Three-dimensional extrusion bioprinting technology aims to become a fundamental tool for tissue regeneration using cell-loaded hydrogels. These biomaterials must have highly specific mechanical and biological properties that allow them to generate biosimilar structures by successive layering of material while maintaining cell viability. The [...] Read more.
Three-dimensional extrusion bioprinting technology aims to become a fundamental tool for tissue regeneration using cell-loaded hydrogels. These biomaterials must have highly specific mechanical and biological properties that allow them to generate biosimilar structures by successive layering of material while maintaining cell viability. The rheological properties of hydrogels used as bioinks are critical to their printability. Correct printability of hydrogels allows the replication of biomimetic structures, which are of great use in medicine, tissue engineering and other fields of study that require the three-dimensional replication of different tissues. When bioprinting cell-loaded hydrogels, a small amount of culture medium can be added to ensure adequate survival, which can modify the rheological properties of the hydrogels. GelMA is a hydrogel used in bioprinting, with very interesting properties and rheological parameters that have been studied and defined for its basic formulation. However, the changes that occur in its rheological parameters and therefore in its printability, when it is mixed with the culture medium necessary to house the cells inside, are unknown. Therefore, in this work, a comparative study of GelMA 100% and GelMA in the proportions 3:1 (GelMA 75%) and 1:1 (GelMA 50%) with culture medium was carried out to determine the printability of the gel (using a device of our own invention), its main rheological parameters and its toxicity after the addition of the medium and to observe whether significant differences in cell viability occur. This raises the possibility of its use in regenerative medicine using a 3D extrusion bioprinter. Full article
(This article belongs to the Special Issue 3D and 4D Printing of Polymers: Modeling and Experimental Approaches)
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15 pages, 4227 KiB  
Article
Transcriptome Analysis Reveals Candidate Genes for Light Regulation of Elsinochrome Biosynthesis in Elsinoë arachidis
by Dan Liu, Jingzi Piao, Yang Li, Haiwen Guan, Jingwen Hao and Rujun Zhou
Microorganisms 2024, 12(5), 1027; https://doi.org/10.3390/microorganisms12051027 (registering DOI) - 19 May 2024
Abstract
Light regulation is critical in fungal growth, development, morphogenesis, secondary metabolism, and the biological clock. The fungus Elsinoë arachidis is known to produce the mycotoxin Elsinochrome (ESC), a key factor contributing to its pathogenicity, under light conditions. Although previous studies have predominantly focused [...] Read more.
Light regulation is critical in fungal growth, development, morphogenesis, secondary metabolism, and the biological clock. The fungus Elsinoë arachidis is known to produce the mycotoxin Elsinochrome (ESC), a key factor contributing to its pathogenicity, under light conditions. Although previous studies have predominantly focused on the light-induced production of ESC and its biosynthetic pathways, the detailed mechanisms underlying this process remain largely unexplored. This study explores the influence of light on ESC production and gene expression in E. arachidis. Under white light exposure for 28 days, the ESC yield was observed to reach 33.22 nmol/plug. Through transcriptome analysis, 5925 genes were identified as differentially expressed between dark and white light conditions, highlighting the significant impact of light on gene expression. Bioinformatics identified specific light-regulated genes, including eight photoreceptor genes, five global regulatory factors, and a cluster of 12 genes directly involved in the ESC biosynthesis, with expression trends confirmed by RT-qPCR. In conclusion, the study reveals the substantial alteration in gene expression associated with ESC biosynthesis under white light and identifies potential candidates for in-depth functional analysis. These findings advance understanding of ESC biosynthesis regulation and suggest new strategies for fungal pathogenicity control. Full article
(This article belongs to the Section Microbiomes)
15 pages, 1695 KiB  
Article
Multi-Step Design Optimization for the Improvement of an Outer-Rotor Brushless Direct Current Motor
by Chun-Yu Hsiao and Soe Min Htet
Appl. Sci. 2024, 14(10), 4302; https://doi.org/10.3390/app14104302 (registering DOI) - 19 May 2024
Abstract
Brushless Direct Current (BLDC) motors have seen significant improvements across various electrical applications. The growing focus on motor design research highlights the BLDC motor’s superior efficiency compared to traditional motors, which consume more power. BLDC motors are compact, lightweight, energy-efficient, and easy to [...] Read more.
Brushless Direct Current (BLDC) motors have seen significant improvements across various electrical applications. The growing focus on motor design research highlights the BLDC motor’s superior efficiency compared to traditional motors, which consume more power. BLDC motors are compact, lightweight, energy-efficient, and easy to control, making them ideal for modern applications. This study aims to enhance BLDC motor design and performance by employing the Taguchi method, Response Surface Methodology (RSM), and Finite Element Method (FEM) for multi-stage optimization. A 26-watt BLDC electric fan motor is the reference model for this study. The Taguchi method helps identify optimization points, guiding further enhancements in the second stage. The study proposes a design with improved output power, torque, and efficiency. The final design achieves a 15% higher energy efficiency than the reference model, with a 10 W increase in output power and a 0.032 Nm increase in maximum torque. The FEM analysis using JMAG software v 21.2 validates the proposed design, which shows improved configurations compared to the reference model, demonstrating the efficacy of the optimization techniques for BLDC motor design. Full article
20 pages, 6184 KiB  
Article
Experimental Evaluation of Ceramic Coatings for Die Protection in Low-Pressure Die-Casting Process
by Ainara López-Ortega, Olatz Areitioaurtena, Elena Fuentes, Amaya Igartua, Luis Merchán, Enrique Pardo, Jessica Montero, Roberto Granado, Ignacio Martinez de la Pera, Joannes Mendizabal and Borja Zabala
Coatings 2024, 14(5), 643; https://doi.org/10.3390/coatings14050643 (registering DOI) - 19 May 2024
Abstract
One of the most important factors in the LPDC process is the heat transfer during the solidification of the molten alloys, which is responsible for the resulting microstructure and, thus, the quality of the cast piece. The use of foundry coatings has been [...] Read more.
One of the most important factors in the LPDC process is the heat transfer during the solidification of the molten alloys, which is responsible for the resulting microstructure and, thus, the quality of the cast piece. The use of foundry coatings has been lately suggested as a proper strategy to control the heat transfer while protecting bonded moulds from aluminium adhesion by providing a barrier between the surface and the liquid metal. LPDC die coating failures usually come from the loss of adherence or excessive wear originated in the successive filling processes, which requires stopping production for the reapplication of the coating. In the present work, coatings with different insulation capabilities have been evaluated, in terms of adherence and wear tests, in order to select the most promising alternative for LPDC die coating. This study confirmed that surface preparation and cleanliness are vital for an adequate adhesion of the coatings to ensure their durability. The results evinced that the use of a primer layer provided a higher adhesion of the coatings and considerably improved their perfomance. The coating that presented the best results in terms of adhesion and wear resistance under different abrasive testing conditions was coating B3. Full article
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16 pages, 8059 KiB  
Article
CardioXplorer: An Open-Source Modular Teleoperative Robotic Catheter Ablation System
by Zhouyang Xu, Aya Mutaz Zeidan, Yetao He, Lisa Leung, Calum Byrne, Sachin Sabu, Yuanwei Wu, Zhiyue Chen, Steven E. Williams, Lukas Lindenroth, Jonathan Behar, Christopher Aldo Rinaldi, John Whitaker, Aruna Arujuna, Richard Housden and Kawal Rhode
Robotics 2024, 13(5), 80; https://doi.org/10.3390/robotics13050080 (registering DOI) - 19 May 2024
Abstract
Atrial fibrillation, the most prevalent cardiac arrhythmia, is treated by catheter ablation to isolate electrical triggers. Clinical trials on robotic catheter systems hold promise for improving the safety and efficacy of the procedure. However, expense and proprietary designs hinder accessibility to such systems. [...] Read more.
Atrial fibrillation, the most prevalent cardiac arrhythmia, is treated by catheter ablation to isolate electrical triggers. Clinical trials on robotic catheter systems hold promise for improving the safety and efficacy of the procedure. However, expense and proprietary designs hinder accessibility to such systems. This paper details an open-source, modular, three-degree-of-freedom robotic platform for teleoperating commercial ablation catheters through joystick navigation. We also demonstrate a catheter-agnostic handle interface permitting customization with commercial catheters. Collaborating clinicians performed benchtop targeting trials, comparing manual and robotic catheter navigation performance. The robot reduced task duration by 1.59 s across participants and five trials. Validation through mean motion jerk analysis revealed 35.2% smoother robotic navigation for experts (≥10 years experience) compared to the intermediate group. Yet, both groups achieved smoother robot motion relative to the manual approach, with the experts and intermediates exhibiting 42.2% and 13.6% improvements, respectively. These results highlight the potential of this system for enhancing catheter-based procedures. The source code and designs of CardioXplorer have been made publicly available to lower boundaries and drive innovations that enhance procedure efficacy beyond human capabilities. Full article
(This article belongs to the Section Medical Robotics and Service Robotics)
10 pages, 2783 KiB  
Article
Steric Effects of Alcohols on the [Mn4O4] Cubane-Type Structures
by Yan He, Zheng Zhou and Haixiang Han
Crystals 2024, 14(5), 478; https://doi.org/10.3390/cryst14050478 (registering DOI) - 19 May 2024
Abstract
[M4O4] (M = 3d transition metal) represents an interesting class of compounds featuring cubane-type molecular structures, and particularly, [Mn4O4] cubanes or their derivatives attract much attention by virtue of their potential applications as single-molecule [...] Read more.
[M4O4] (M = 3d transition metal) represents an interesting class of compounds featuring cubane-type molecular structures, and particularly, [Mn4O4] cubanes or their derivatives attract much attention by virtue of their potential applications as single-molecule magnets (SMMs) or catalysts. However, the rational design of desired cubane-related structures is still a challenging subject due to the lack of readily available methods to effectively tune the construction patterns of the molecule assembly. In this work, we report the employment of different alcohols to prepare three cubane-related molecules, Mn2(dhd)4(iPrOH)2 (1), Mn4(dhd)4(OEt)4(EtOH)4 (2) and Mn4(dhd)6(OMe)2(MeOH)2 (3) (dhd = 5,5-dimethyl-2,4-hexanedione). Interestingly, the bulkiest iPrOH leads to simple rhombic dimer molecule 1. It can be deemed a rudimentary structure oftetranuclear [Mn4O4] cubane 2, which can be realized by the use of less bulky EtOH. In addition, the least bulky MeOH promotes the assembly of the cubanes, eventually bringing about defective dicubane molecular cluster 3. The accurate crystal structures of 13 were modeled by single-crystal X-ray diffraction, and their electronic structures were investigated through absorption spectroscopy coupled with theoretical calculations. Overall, this work demonstrates a systematic study on controlling cubane-type structures of Mn-based compounds by applying different solvents, which provides a new means to design functional molecules for specific applications. Full article
(This article belongs to the Section Organic Crystalline Materials)
13 pages, 552 KiB  
Article
Neuregulin 2 Is a Candidate Gene for Autism Spectrum Disorder
by Wei-Hsien Chien, Chia-Hsiang Chen, Min-Chih Cheng, Yu-Yu Wu and Susan Shur-Fen Gau
Int. J. Mol. Sci. 2024, 25(10), 5547; https://doi.org/10.3390/ijms25105547 (registering DOI) - 19 May 2024
Abstract
Autism spectrum disorder (ASD) is a complex neurodevelopmental disorder with heterogeneous and complex genetic underpinnings. Our previous microarray gene expression profiling identified significantly different neuregulin-2 gene (NRG2) expression between ASD patients and controls. Thus, we aimed to clarify whether NRG2 is a candidate [...] Read more.
Autism spectrum disorder (ASD) is a complex neurodevelopmental disorder with heterogeneous and complex genetic underpinnings. Our previous microarray gene expression profiling identified significantly different neuregulin-2 gene (NRG2) expression between ASD patients and controls. Thus, we aimed to clarify whether NRG2 is a candidate gene associated with ASD. The study consisted of two stages. First, we used real-time quantitative PCR in 20 ASDs and 20 controls to confirm the microarray gene expression profiling results. The average NRG2 gene expression level in patients with ASD (3.23 ± 2.80) was significantly lower than that in the controls (9.27 ± 4.78, p < 0.001). Next, we conducted resequencing of all the exons of NRG2 in a sample of 349 individuals with ASD, aiming to identify variants of the NRG2 associated with ASD. We identified three variants, including two single nucleotide variants (SNVs), IVS3 + 13A > G (rs889022) and IVS10 + 32T > A (rs182642591), and one small deletion at exon 11 of NRG2 (delGCCCGG, rs933769137). Using data from the Taiwan Biobank as the controls, we found no significant differences in allele frequencies of rs889022 and rs182642591 between two groups. However, there is a significant difference in the genotype and allele frequency distribution of rs933769137 between ASDs and controls (p < 0.0001). The small deletion is located in the EGF-like domain at the C-terminal of the NRG2 precursor protein. Our findings suggest that NRG2 might be a susceptibility gene for ASD. Full article
(This article belongs to the Special Issue Genetic Variations in Human Diseases)
23 pages, 9554 KiB  
Article
Effects of a Complex Environment on Fatigue and Self-Healing Characterization of Asphalt Composites Containing Rock Asphalt
by Ruixia Li, Shangjun Yu, Hailong Chen, Jiahui Wu, Yijun Chen and Jinchao Yue
Materials 2024, 17(10), 2453; https://doi.org/10.3390/ma17102453 (registering DOI) - 19 May 2024
Abstract
In recent years, asphalt pavement has been subjected to varied environmental conditions during its service life, conditions that predispose it to deformation and cracking. To enhance the performance of asphalt pavement, rock asphalt has been selected as a modifier due to its good [...] Read more.
In recent years, asphalt pavement has been subjected to varied environmental conditions during its service life, conditions that predispose it to deformation and cracking. To enhance the performance of asphalt pavement, rock asphalt has been selected as a modifier due to its good compatibility with virgin asphalt binder and its ability to improve the fatigue cracking resistance of asphalt mixtures. Although scholars have conducted some studies on rock asphalt mixtures, research on the fatigue and self-healing performance of these mixtures under conditions such as ultraviolet (UV) aging and freeze–thaw remains limited. This paper presents findings from a study that employs a combined fatigue-healing test to assess the impact of such complex environmental factors on the fatigue and self-healing properties of fine aggregate matrix (FAM) mixtures containing three types of rock asphalts, i.e., Buton, Qingchuan (QC), and Uintaite Modifier (UM). The analysis of fatigue-healing test results, grounded in viscoelastic continuum damage (VECD) theory, indicates that rock asphalt can extend the fatigue life of FAM mixtures, albeit with a concomitant decrease in their self-healing capabilities. The study further reveals that UV aging, freeze–thaw, and UV aging–freeze–thaw conditions all led to a diminution in the fatigue and self-healing properties of FAM mixtures. However, FAM mixtures containing rock asphalt demonstrated greater resilience against these reductions. Atomic force microscope (AFM) results indicate that UV aging reduced the number of bee-structures and enlarged their area, whereas the incorporation of rock asphalt enhanced the uniformity of these structures’ distribution, thereby improving the fatigue cracking resistance of FAM mixtures. Fourier transform infrared spectroscopy (FTIR) analysis reveals that while UV aging increased the carbonyl and sulfoxide indices within the asphalt binder, rock asphalt is effective in mitigating this effect to a certain degree, thereby enhancing the aging resistance of FAM mixtures. Full article
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13 pages, 4650 KiB  
Article
Mechanism Analysis and Optimization Design of Exoskeleton Robot with Non-Circular Gear–Pentabar Mechanism
by Guibin Wang, Maile Zhou, Hao Sun, Zhaoxiang Wei, Herui Dong, Tingbo Xu and Daqing Yin
Machines 2024, 12(5), 351; https://doi.org/10.3390/machines12050351 (registering DOI) - 19 May 2024
Abstract
To address the complex structure of existing rod mechanism exoskeleton robots and the difficulty in solving the motion trajectory of multi−rod mechanisms, an exoskeleton knee robot with a differential non−circular gear–pentarod mechanism is designed based on non−circular gears with arbitrary transmission ratios to [...] Read more.
To address the complex structure of existing rod mechanism exoskeleton robots and the difficulty in solving the motion trajectory of multi−rod mechanisms, an exoskeleton knee robot with a differential non−circular gear–pentarod mechanism is designed based on non−circular gears with arbitrary transmission ratios to constrain the degrees of freedom of the R-para-rod mechanism. In this study, the kinematic model of a non-circular gear–five−rod mechanism is established based on motion mapping theory by obtaining the normal motion positions of the human lower limb. An optimization design software for the non-circular gear–five−rod mechanism is developed using the MATLAB 2018b visualization platform, with the non−circular active gear as the sole input variable. A set of ideal parameters is obtained through parameter adjustment and optimal parameter selection, and the corresponding trajectories are compared with human trajectories. The three−dimensional model of the mechanism is established according to the obtained parameters, and the motion simulation of the non−circular gear–five−bar mechanism demonstrates that the mechanism can better reproduce the expected human knee joint motion posture, meeting the working requirements of an exoskeleton knee robot. Full article
(This article belongs to the Section Robotics, Mechatronics and Intelligent Machines)
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24 pages, 8090 KiB  
Article
Karenia brevis and Pyrodinium bahamense Utilization of Dissolved Organic Matter in Urban Stormwater Runoff and Rainfall Entering Tampa Bay, Florida
by Amanda L. Muni-Morgan, Mary G. Lusk and Cynthia A. Heil
Water 2024, 16(10), 1448; https://doi.org/10.3390/w16101448 (registering DOI) - 19 May 2024
Abstract
This study investigated how nitrogen and dissolved organic matter (DOM) from stormwater runoff and rainfall support the growth of Karenia brevis and Pyrodinium bahamense. Excitation–emission matrix spectroscopy coupled with parallel factor analysis tracked changes in the optical properties of DOM in each [...] Read more.
This study investigated how nitrogen and dissolved organic matter (DOM) from stormwater runoff and rainfall support the growth of Karenia brevis and Pyrodinium bahamense. Excitation–emission matrix spectroscopy coupled with parallel factor analysis tracked changes in the optical properties of DOM in each bioassay, revealing greater reactivity of terrestrial humic-like DOM. Significant increases in cell yield and specific growth rates were observed upon additions of runoff for both species, with significant increases in specific growth rates upon the addition of a 2 in simulated rain event for P. bahamense only. By hour 48, 100% of the dissolved organic nitrogen (DON) in each treatment was utilized by P. bahamense, and by hour 72, over 50% of the DON was utilized by K. brevis. The percentage of bioavailable dissolved organic carbon (DOC) was greater for P. bahamense compared to K. brevis, suggesting a greater affinity for DOC compounds by P. bahamense. However, the bioavailability of DOM for each species could be owed to distinct chemical characteristics of labile DOM conveyed from each site. This study demonstrates that stormwater runoff and rainfall are both sources of labile DOM and DON for K. brevis and P. bahamense, which has implications for blooms of these species in Tampa Bay waters. Full article
(This article belongs to the Special Issue Eutrophication and Harmful Algae in Aquatic Ecosystems)
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14 pages, 401 KiB  
Opinion
Special Issue on Ability-Related Emotional Intelligence: An Introduction
by Michael D. Robinson
J. Intell. 2024, 12(5), 51; https://doi.org/10.3390/jintelligence12050051 (registering DOI) - 19 May 2024
Abstract
Emotionally intelligent people are thought to be more skilled in recognizing, thinking about, using, and regulating emotions. This construct has garnered considerable interest, but initial enthusiasm has faded and it is time to take stock. There is consensus that ability-related measures of emotional [...] Read more.
Emotionally intelligent people are thought to be more skilled in recognizing, thinking about, using, and regulating emotions. This construct has garnered considerable interest, but initial enthusiasm has faded and it is time to take stock. There is consensus that ability-related measures of emotional intelligence (EI) can be favored to self-report tests, in part because the resulting scores cannot be equated with personality traits. However, there are questions surrounding measurement as well as predictive value. Experts in the field were encouraged to chart new directions, with the idea that these new directions could reinvigorate EI scholarship. Special Issue papers speak to theory, mechanism, measurement, and training. In addition, these papers seek to forge links with research traditions focused on interpersonal perception, emotional awareness, and emotion regulation. As a result of these efforts, new insights into what EI is and how it works can be anticipated in upcoming years. Full article
8 pages, 259 KiB  
Article
Persistence and Stochastic Extinction in a Lotka–Volterra Predator–Prey Stochastically Perturbed Model
by Leonid Shaikhet and Andrei Korobeinikov
Mathematics 2024, 12(10), 1588; https://doi.org/10.3390/math12101588 (registering DOI) - 19 May 2024
Abstract
The classical Lotka–Volterra predator–prey model is globally stable and uniformly persistent. However, in real-life biosystems, the extinction of species due to stochastic effects is possible and may occur if the magnitudes of the stochastic effects are large enough. In this paper, we consider [...] Read more.
The classical Lotka–Volterra predator–prey model is globally stable and uniformly persistent. However, in real-life biosystems, the extinction of species due to stochastic effects is possible and may occur if the magnitudes of the stochastic effects are large enough. In this paper, we consider the classical Lotka–Volterra predator–prey model under stochastic perturbations. For this model, using an analytical technique based on the direct Lyapunov method and a development of the ideas of R.Z. Khasminskii, we find the precise sufficient conditions for the stochastic extinction of one and both species and, thus, the precise necessary conditions for the stochastic system’s persistence. The stochastic extinction occurs via a process known as the stabilization by noise of the Khasminskii type. Therefore, in order to establish the sufficient conditions for extinction, we found the conditions for this stabilization. The analytical results are illustrated by numerical simulations. Full article
(This article belongs to the Special Issue Stochastic Models in Mathematical Biology, 2nd Edition)
18 pages, 1059 KiB  
Review
Therapeutic Potential of Bovine Milk-Derived Extracellular Vesicles
by Madhusha Prasadani, Suranga Kodithuwakku, Georgia Pennarossa, Alireza Fazeli and Tiziana A. L. Brevini
Int. J. Mol. Sci. 2024, 25(10), 5543; https://doi.org/10.3390/ijms25105543 (registering DOI) - 19 May 2024
Abstract
Milk is a fundamental component of the human diet, owing to its substantial nutritional content. In addition, milk contains nanoparticles called extracellular vesicles (EVs), which have indicated their potential beneficial roles such as cell-to-cell communication, disease biomarkers, and therapeutics agents. Amidst other types [...] Read more.
Milk is a fundamental component of the human diet, owing to its substantial nutritional content. In addition, milk contains nanoparticles called extracellular vesicles (EVs), which have indicated their potential beneficial roles such as cell-to-cell communication, disease biomarkers, and therapeutics agents. Amidst other types of EVs, milk EVs (MEVs) have their significance due to their high abundance, easy access, and stability in harsh environmental conditions, such as low pH in the gut. There have been plenty of studies conducted to evaluate the therapeutic potential of bovine MEVs over the past few years, and attention has been given to their engineering for drug delivery and targeted therapy. However, there is a gap between the experimental findings available and clinical trials due to the many challenges related to EV isolation, cargo, and the uniformity of the material. This review aims to provide a comprehensive comparison of various techniques for the isolation of MEVs and offers a summary of the therapeutic potential of bovine MEVs described over the last decade, analyzing potential challenges and further applications. Although a number of aspects still need to be further elucidated, the available data point to the role of MEVs as a potential candidate with therapeutics potential, and the supplementation of MEVs would pave the way to understanding their in-depth effects. Full article
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17 pages, 437 KiB  
Review
A Comprehensive Survey on the Investigation of Machine-Learning-Powered Augmented Reality Applications in Education
by Haseeb Ali Khan, Sonain Jamil, Md. Jalil Piran, Oh-Jin Kwon and Jong-Weon Lee
Technologies 2024, 12(5), 72; https://doi.org/10.3390/technologies12050072 (registering DOI) - 19 May 2024
Abstract
Machine learning (ML) is enabling augmented reality (AR) to gain popularity in various fields, including gaming, entertainment, healthcare, and education. ML enhances AR applications in education by providing accurate visualizations of objects. For AR systems, ML algorithms facilitate the recognition of objects and [...] Read more.
Machine learning (ML) is enabling augmented reality (AR) to gain popularity in various fields, including gaming, entertainment, healthcare, and education. ML enhances AR applications in education by providing accurate visualizations of objects. For AR systems, ML algorithms facilitate the recognition of objects and gestures from kindergarten through university. The purpose of this survey is to provide an overview of various ways in which ML techniques can be applied within the field of AR within education. The first step is to describe the background of AR. In the next step, we discuss the ML models that are used in AR education applications. Additionally, we discuss how ML is used in AR. Each subgroup’s challenges and solutions can be identified by analyzing these frameworks. In addition, we outline several research gaps and future research directions in ML-based AR frameworks for education. Full article
27 pages, 6260 KiB  
Article
Numerical Investigation of Innovative Photovoltaic–Thermal (PVT) Collector Designs for Electrical and Thermal Enhancement
by Ziqiang Wang, Gaoyang Hou, Hessam Taherian and Ying Song
Energies 2024, 17(10), 2429; https://doi.org/10.3390/en17102429 (registering DOI) - 19 May 2024
Abstract
Photovoltaic–thermal (PVT) technology is gaining popularity due to the diminishing availability of traditional fossil fuels and escalating environmental concerns. Enhancing the heat dissipation of PVT to improve its electrical and thermal performance remains a significant task. This study simulates the thermodynamic and heat [...] Read more.
Photovoltaic–thermal (PVT) technology is gaining popularity due to the diminishing availability of traditional fossil fuels and escalating environmental concerns. Enhancing the heat dissipation of PVT to improve its electrical and thermal performance remains a significant task. This study simulates the thermodynamic and heat transfer characteristics in multiple novel PVT structures by examining the impact of various factors such as collector materials, radiation intensity, mass flow rate, and inlet temperature. This work also identifies the optimal mass flow rate for locations with different solar radiation. The numerical results indicate that the electrical efficiency of a designed cylindrical structure has increased by 1.73% while the thermal efficiency has increased by 8.29%. Aluminum is identified as the most cost-effective material for the collector. The optimal mass flow rates in selected locations of Xining, Taiyuan, and Turpan are 0.36 kg/s, 0.35 kg/s, and 0.30 kg/s, respectively. The numerical results provide valuable insight into optimizing the design and operating conditions of PVT systems. Full article
(This article belongs to the Section A2: Solar Energy and Photovoltaic Systems)
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18 pages, 21186 KiB  
Article
Investigation of Residual Stress Distribution and Fatigue of 7050-T7451 Alloy Hole Components with Laser Shock and Ultrasonic Extrusion
by Yinfang Jiang, Xiancheng Liu, Yangyang Wang, Lingling Cui, Guang Ji and Wei Liu
Metals 2024, 14(5), 597; https://doi.org/10.3390/met14050597 (registering DOI) - 19 May 2024
Abstract
Small-hole structures, such as the millions of fastener holes found on aircraft, are typical stress-concentration structures prone to fatigue failure. To further improve the strengthening process of this small-hole structure, we make up for the limitations of laser shock processing (LSP) of small [...] Read more.
Small-hole structures, such as the millions of fastener holes found on aircraft, are typical stress-concentration structures prone to fatigue failure. To further improve the strengthening process of this small-hole structure, we make up for the limitations of laser shock processing (LSP) of small holes by combining it with the ultrasonic extrusion strengthening (UES) process to form a new strengthening method—laser shock and ultrasonic extrusion strengthening (LUE). The influence of the LUE process sequence and process parameters on residual stress distribution was studied through FEM, and the gain of fatigue life of specimens after LUE strengthening was also explored through tests. The results show that when using LUE technology, the friction force decreases with the increase in amplitude and decreases by 3.2% when the amplitude is maximum. The LUE process eliminates the thickness effect generated by LSP, which can achieve good stress distribution of small-hole components under smaller laser shock peak pressure, and reduces equipment power. LUE can significantly improve the fatigue life of small-hole components, and the maximum fatigue life gain can be up to 310.66%. Full article
(This article belongs to the Special Issue Fracture and Fatigue of Advanced Metallic Materials)
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21 pages, 11447 KiB  
Article
Experimental Study on the Microfabrication and Mechanical Properties of Freeze–Thaw Fractured Sandstone under Cyclic Loading and Unloading Effects
by Taoying Liu, Wenbin Cai, Yeshan Sheng and Jun Huang
Materials 2024, 17(10), 2451; https://doi.org/10.3390/ma17102451 (registering DOI) - 19 May 2024
Abstract
A series of freeze–thaw cycling tests, as well as cyclic loading and unloading tests, have been conducted on nodular sandstones to investigate the effect of fatigue loading and freeze–thaw cycling on the damage evolution of fractured sandstones based on damage mechanics theory, the [...] Read more.
A series of freeze–thaw cycling tests, as well as cyclic loading and unloading tests, have been conducted on nodular sandstones to investigate the effect of fatigue loading and freeze–thaw cycling on the damage evolution of fractured sandstones based on damage mechanics theory, the microstructure and sandstone pore fractal theory. The results show that the number of freeze–thaw cycles, the cyclic loading level, the pore distribution and the complex program are important factors affecting the damage evolution of rocks. As the number of freeze–thaw cycles rises, the peak strength, modulus of elasticity, modulus of deformation and damping ratio of the sandstone all declined. Additionally, the modulus of elasticity and deformation increase nonlinearly as the cyclic load level rises. With the rate of increase decreasing, while the dissipation energy due to hysteresis increases gradually and at an increasing rate, and the damping ratio as a whole shows a gradual decrease, with a tendency to increase at a later stage. The NRM (Nuclear Magnetic Resonance) demonstrated that the total porosity and micro-pores of the sandstone increased linearly with the number of freeze–thaw cycles and that the micro-porosity was more sensitive to freeze–thaw, gradually shifting towards meso-pores and macro-pores; simultaneously, the SEM (Scanning Electron Microscope) indicated that the more freeze–thaw cycles there are, the more micro-fractures and holes grow and penetrate each other and the more loose the structure is, with an overall nest-like appearance. To explore the mechanical behavior and mechanism of cracked rock in high-altitude and alpine areas, a damage model under the coupling of freeze–thaw-fatigue loading was established based on the loading and unloading response ratio theory and strain equivalence principle. Full article
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20 pages, 13287 KiB  
Article
Morphological and Molecular Analysis Identified a Subspecies of Crassostrea ariakensis (Fujita, 1913) along the Coast of Asia
by Ya Chen, Cui Li, Ruijing Lu and Haiyan Wang
Genes 2024, 15(5), 644; https://doi.org/10.3390/genes15050644 (registering DOI) - 19 May 2024
Abstract
Crassostrea ariakensis (Fujita, 1913) is one of the most important economic and ecological oysters that is naturally distributed along the coast of Asia, separated by the Yangtze River estuary. They are usually compared as different populations, while there is no consensus on whether [...] Read more.
Crassostrea ariakensis (Fujita, 1913) is one of the most important economic and ecological oysters that is naturally distributed along the coast of Asia, separated by the Yangtze River estuary. They are usually compared as different populations, while there is no consensus on whether C. ariakensis in northern and southern areas should be considered as two species or subspecies. Here, we analyzed morphological characteristics, COI, 16s rRNA, mitogenome sequences, and species delimitation analysis (ASAP and PTP) to resolve the intraspecific taxonomic status of the C. ariakensis. Phylogenetic and ASAP analysis highlight that C. ariakensis was divided into N-type and S-type. PTP was unable to differentiate between the two types of C. ariakensis. The divergence time of N-type and S-type C. ariakinsis is estimated to be 1.6 Mya, using the relaxed uncorrelated lognormal clock method. Additionally, significant morphological differences exist between the two groups in terms of the adductor muscle scar color. Despite these differences, the COI (0.6%) and 16S rRNA (0.6%) genetic distance differences between N-type and S-type C. ariakensis has not yet reached the interspecific level. These results suggest that N-type and S-type C. ariakensis should be treated as different subspecies and renamed as C. ariakensis ariakensis subsp. nov and C. ariakensis meridioyangtzensis subsp. nov. Full article
(This article belongs to the Special Issue Genetic Evolution of Marine Shellfish (Volume II))
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17 pages, 1431 KiB  
Article
An Incubation System for the Simulation of Ammonia Emissions from Soil Surface-Applied Slurry: Effect of pH and Acid Type
by Nils Carsten Thomas Ellersiek and Hans-Werner Olfs
Agronomy 2024, 14(5), 1078; https://doi.org/10.3390/agronomy14051078 (registering DOI) - 19 May 2024
Abstract
Acidification of slurry is a promising approach for reducing ammonia emissions during the application procedure. Since only a few studies have been conducted focusing on ammonia emissions during the application of liquid organic fertilizers on the soil surface, a suitable incubation system was [...] Read more.
Acidification of slurry is a promising approach for reducing ammonia emissions during the application procedure. Since only a few studies have been conducted focusing on ammonia emissions during the application of liquid organic fertilizers on the soil surface, a suitable incubation system was developed to evaluate the effects of acidification under controlled conditions. This incubation system was used to measure the ammonia emissions of various liquid organic fertilizers. The substrates were acidified with sulfuric and citric acid to different pH values to determine both the influence of the pH value of the substrates and of the type of acid on the ammonia emissions. The emissions decreased with declining pH value, and the reduction in emissions compared to the initial pH of the substrate was over 86% for pH 6.5 and over 98% for pH 6.0 and below. At the same pH value, the ammonia emissions did not differ between substrates acidified with citric acid and sulfuric acid, although more than twice as much 50% citric acid was required compared to 96% sulfuric acid to achieve the same pH value. Overall, our results demonstrate that the incubation system used is suitable for measuring ammonia emissions from surface-applied liquid organic fertilizers. The system allows for the differentiation of emission levels at various pH levels and is therefore suitable for testing the effectiveness of additives for reducing ammonia emissions from liquid organic fertilizers. Full article

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