The 2023 MDPI Annual Report has
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Article
On Conditional Axioms and Associated Inference Rules
by Joaquín Borrego-Díaz, Andrés Cordón-Franco and Francisco Félix Lara-Martín
Axioms 2024, 13(5), 306; https://doi.org/10.3390/axioms13050306 (registering DOI) - 07 May 2024
Abstract
In the present paper, we address the following general question in the framework of classical first-order logic. Assume that a certain mathematical principle can be formalized in a first-order language by a set E of conditional formulas of the form [...] Read more.
In the present paper, we address the following general question in the framework of classical first-order logic. Assume that a certain mathematical principle can be formalized in a first-order language by a set E of conditional formulas of the form α(v)β(v). Given a base theory T, we can use the set of conditional formulas E to extend the base theory in two natural ways. Either we add to T each formula in E as a new axiom (thus obtaining a theory denoted by T+E) or we extend T by using the formulas in E as instances of an inference rule (thus obtaining a theory denoted by T+ERule). The theory T+E will be stronger than T+ERule, but how much stronger can T+E be? More specifically, is T+E conservative over T+ERule for theorems of some fixed syntactical complexity Γ? Under very general assumptions on the set of conditional formulas E, we obtain two main conservation results in this regard. Firstly, if the formulas in E have low syntactical complexity with respect to some prescribed class of formulas Π and in the applications of ERule side formulas from the class Π and can be eliminated (in a certain precise sense), then T+E is B(Π)-conservative over T+ERule. Secondly, if, in addition, E is a finite set with m conditional sentences, then nested applications of ERule of a depth at most of m suffice to obtain B(Π) conservativity. These conservation results between axioms and inference rules extend well-known conservation theorems for fragments of first-order arithmetics to a general, purely logical framework. Full article
(This article belongs to the Topic Mathematical Modeling)
19 pages, 464 KiB  
Article
The Impact of Deficit Irrigation on the Agronomic Performance and Chemical Composition of Scolymus hispanicus L.
by Nikolaos Polyzos, Beatriz H. Paschoalinotto, Tânia C. S. P. Pires, Mikel Añibarro-Ortega, Ricardo Calhelha, Isabel C. F. R. Ferreira, Maria Inês Dias, Lillian Barros and Spyridon A. Petropoulos
Horticulturae 2024, 10(5), 479; https://doi.org/10.3390/horticulturae10050479 (registering DOI) - 07 May 2024
Abstract
In the current study, the effects of drought stress on the growth and phytochemical profile of Scolymus hispanicus L. (a.k.a. golden thistle) were evaluated. Plants were treated with three irrigation regimes, e.g., plants that received only rainwater (Control; C), deficit irrigation (I1; 50% [...] Read more.
In the current study, the effects of drought stress on the growth and phytochemical profile of Scolymus hispanicus L. (a.k.a. golden thistle) were evaluated. Plants were treated with three irrigation regimes, e.g., plants that received only rainwater (Control; C), deficit irrigation (I1; 50% of field capacity (FC)), and full irrigation (Ι2; 100% of FC). The fresh weight of the rosette of leaves was not negatively impacted by deficit irrigation, whereas root development was severely restrained compared to control and I2 treatments. Drought stress conditions had a positive effect on the nutritional properties of the golden thistle since the treatments of control and deficit irrigation showed the highest content of macronutrients and energy. Oxalic acid was the richest organic acid, especially under the I1 regime. Similarly, α-tocopherol was the only identified vitamin E isoform, whose content was also doubled in I1 treatment. Raffinose, glucose, and sucrose were the most abundant free sugars in amounts that varied among the irrigation treatments, while the total and distinct free sugar content was the highest for the I1 treatment. The most abundant detected fatty acid compounds were α-linolenic acid, followed by palmitic and linoleic acid, with the highest amount being detected in C, I1, and I2 treatments, respectively. Flavonoids were the only class of polyphenols detected in golden thistle leaves, including mostly kaempferol and quercetin derivatives. The greatest antioxidant potency was shown for the control and I1 treatments (for OxHLIA and TBARS methods, respectively). The evaluated leaf samples recorded a varied antimicrobial effect for the different bacterial strains and fungi, whereas no cytotoxic, hepatotoxic, and anti-inflammatory effects against the tested cell lines were recorded. Finally, the mineral content of leaves was significantly affected by the irrigation regime, with Ca, Mg, Cu, and Zn being the highest for the I1 treatment, while the I2 treatment had the highest content of K, Fe, and Mn and the lowest Na content. In conclusion, deficit irrigation showed promising results since it improved the phytochemical content without compromising the fresh weight of leaves, and thus it could be suggested as a sustainable agronomic practice for producing high-added value products without significant constraints in growth development and yield parameters of golden thistle. Full article
(This article belongs to the Special Issue Horticultural Production under Drought Stress)
14 pages, 691 KiB  
Review
Lemna minor: Unlocking the Value of This Duckweed for the Food and Feed Industry
by Diana Sosa, Felipe M. Alves, Miguel A. Prieto, Mariana C. Pedrosa, Sandrina A. Heleno, Lillian Barros, Manuel Feliciano and Márcio Carocho
Foods 2024, 13(10), 1435; https://doi.org/10.3390/foods13101435 (registering DOI) - 07 May 2024
Abstract
Duckweed (Lemna minor L.) is a small floating aquatic plant that has an important economic impact in several industrial areas. With its high biomass production, reasonable protein content, and resilience to several climates, it has been attracting increasing interest for potential use [...] Read more.
Duckweed (Lemna minor L.) is a small floating aquatic plant that has an important economic impact in several industrial areas. With its high biomass production, reasonable protein content, and resilience to several climates, it has been attracting increasing interest for potential use in animal and human food systems. Historically consumed in southwest Asia, this duckweed is now gaining attention as a potential novel food in Europe. This manuscript explores the contributions of duckweed to various food and feed industries, including aquaculture and livestock, while also pointing out the incipient research carried out for human consumption. Most importantly, it highlights the potential of Lemna minor as a vegetable for future human consumption whether eaten whole or through extraction of its nutrients. Full article
(This article belongs to the Section Plant Foods)
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18 pages, 830 KiB  
Article
Exploiting the Potential of Powdered Blends of Recovered Sunflower Seed Cake Phenolics and Whey—Development of Sustainable Food Additives
by Anna Michalska-Ciechanowska, Jessica Brzezowska, Krzysztof Lech, Klaudia Masztalerz, Malgorzata Korzeniowska, Aleksandra Zambrowicz and Marek Szoltysik
Foods 2024, 13(10), 1433; https://doi.org/10.3390/foods13101433 (registering DOI) - 07 May 2024
Abstract
The management of side streams from the food industry, especially oil and dairy by-products, has become an important issue linked to the European Commission’s recommendations for a circular economy. This study aimed to obtain sustainable food additives in the form of soluble-type powders [...] Read more.
The management of side streams from the food industry, especially oil and dairy by-products, has become an important issue linked to the European Commission’s recommendations for a circular economy. This study aimed to obtain sustainable food additives in the form of soluble-type powders composed of whey and recovered phenolics originating from sunflower seed cake. In order to valorise these di-blend products, the powders were characterised in terms of their physical, chemical, and sensory attributes. Based on the study findings, the addition of sunflower seed cake washouts (SSCWs) to whey (Wh) decreased the dry matter in the feed that affected the viscosity and drying yield. The addition of SSCWs did not have a significant effect on the physical properties of powders, except for colour. By-product management proposed in the study resulted in the production of nutritious and ready-to-use products in powder form with improved functional properties in terms of phenolic compounds and antioxidant capacity. The powders were sensorially appealing with a tangy sourness entwined with a delicate interplay of sweet and salty flavours, which can be easily incorporated into different types of foodstuffs. Full article
12 pages, 573 KiB  
Article
A Lightweight Convolutional Neural Network Method for Two-Dimensional PhotoPlethysmoGraphy Signals
by Feng Zhao, Xudong Zhang and Zhenyu He
Appl. Sci. 2024, 14(10), 3963; https://doi.org/10.3390/app14103963 (registering DOI) - 07 May 2024
Abstract
Data information security on wearable devices has emerged as a significant concern among users, so it becomes urgent to explore authentication methods based on wearable devices. Using PhotoPlethysmoGraphy (PPG) signals for identity authentication has been proven effective in biometric authentication. This paper proposes [...] Read more.
Data information security on wearable devices has emerged as a significant concern among users, so it becomes urgent to explore authentication methods based on wearable devices. Using PhotoPlethysmoGraphy (PPG) signals for identity authentication has been proven effective in biometric authentication. This paper proposes a convolutional neural network authentication method based on 2D PPG signals applied to wearable devices. This method uses Markov Transition Field technology to convert one-dimensional PPG signal data into two-dimensional image data, which not only retains the characteristics of the signal but also enriches the spatial information. Afterward, considering that wearable devices usually have limited resources, a lightweight convolutional neural network model is also designed in this method, which reduces resource consumption and computational complexity while ensuring high performance. It is proved experimentally that this method achieves 98.62% and 96.17% accuracy on the training set and test set, respectively, an undeniable advantage compared to the traditional one-dimensional deep learning method and the classical two-dimensional deep learning method. Full article
(This article belongs to the Special Issue Machine Learning Based Biomedical Signal Processing)
19 pages, 3487 KiB  
Article
Temperature-Wise Calibration Increases the Accuracy of DNA Methylation Levels Determined by High-Resolution Melting (HRM)
by Katja Zappe and Margit Cichna-Markl
Int. J. Mol. Sci. 2024, 25(10), 5082; https://doi.org/10.3390/ijms25105082 (registering DOI) - 07 May 2024
Abstract
High-resolution melting (HRM) is a cost-efficient tool for targeted DNA methylation analysis. HRM yields the average methylation status across all CpGs in PCR products. Moreover, it provides information on the methylation pattern, e.g., the occurrence of monoallelic methylation. HRM assays have to be [...] Read more.
High-resolution melting (HRM) is a cost-efficient tool for targeted DNA methylation analysis. HRM yields the average methylation status across all CpGs in PCR products. Moreover, it provides information on the methylation pattern, e.g., the occurrence of monoallelic methylation. HRM assays have to be calibrated by analyzing DNA methylation standards of known methylation status and mixtures thereof. In general, DNA methylation levels determined by the classical calibration approach, including the whole temperature range in between normalization intervals, are in good agreement with the mean of the DNA methylation status of individual CpGs determined by pyrosequencing (PSQ), the gold standard of targeted DNA methylation analysis. However, the classical calibration approach leads to highly inaccurate results for samples with heterogeneous DNA methylation since they result in more complex melt curves, differing in their shape compared to those of DNA standards and mixtures thereof. Here, we present a novel calibration approach, i.e., temperature-wise calibration. By temperature-wise calibration, methylation profiles over temperature are obtained, which help in finding the optimal calibration range and thus increase the accuracy of HRM data, particularly for heterogeneous DNA methylation. For explaining the principle and demonstrating the potential of the novel calibration approach, we selected the promoter and two enhancers of MGMT, a gene encoding the repair protein MGMT. Full article
(This article belongs to the Special Issue Biomarkers in Cancers: New Advances)
12 pages, 665 KiB  
Article
Retinal Vascular Abnormalities and Clinical Parameters in Systemic Sclerosis
by Rosario Foti, Marco Zeppieri, Roberta Foti, Elisa Visalli, Giorgio Amato, Roberta Amato, Edoardo Dammino, Fabiana D’Esposito and Caterina Gagliano
J. Clin. Med. 2024, 13(10), 2738; https://doi.org/10.3390/jcm13102738 (registering DOI) - 07 May 2024
Abstract
Background: Systemic sclerosis is a complex autoimmune disease characterized by vasculopathy, fibrosis, and immune dysregulation. Ocular manifestations in these patients are increasingly recognized, suggesting potential correlations between systemic vascular abnormalities and ocular microvascular changes. Advancements in molecular immunology and imaging technology using [...] Read more.
Background: Systemic sclerosis is a complex autoimmune disease characterized by vasculopathy, fibrosis, and immune dysregulation. Ocular manifestations in these patients are increasingly recognized, suggesting potential correlations between systemic vascular abnormalities and ocular microvascular changes. Advancements in molecular immunology and imaging technology using ocular coherence tomography (OCT) have unveiled intricate pathways underlying possible disease pathogenesis. Understanding the interplay between retinal vascular abnormalities and molecular immunology parameters could provide insights into disease mechanisms and potential biomarkers. Purpose: The aim of this study was to investigate vascular abnormalities, detected with optical coherence tomography angiography (OCT-A), in systemic sclerosis patients and to find correlations between the severity of the disease detected with molecular immunology findings and OCT-A parameters. Methods: A group of 32 systemic sclerosis patients were compared with 9 healthy controls. Ganglion cell complex thickness (GCC), retina thickness of the fovea and parafovea, nerve fiber layer thickness (RNFL) and cup/disc area ratio were investigated using OCT. Vessel density (VD) of the superficial (SCP) and deep capillary plexus (DCP) of the whole macular area and ETDRS grid, size of the foveal avascular zone (FAZ) and vessel density of the radial peripapillary capillary plexus (RPCP) were evaluated using OCT-A. Modified Rodnan skin score (mRSS), capillaroscopy and disease duration were used to stage disease severity. Results: There was a statistically significant reduction in retina thickness of the fovea and parafovea, VD of the whole DCP, VD of the SCP and DCP in ETDRS grid in the patient group compared to controls (p < 0.001). The patients presented a significant enlargement of the FAZ (p 0.005). No significant correlation between OCT and OCT-A parameters and disease severity scores was found. Conclusions: OCT-A could represent a non-invasive tool to detect retinal microvascular damage in systemic sclerosis. Full article
(This article belongs to the Special Issue New Clinical Treatment for Ocular Vascular Disease and Fundus Disease)
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16 pages, 1262 KiB  
Article
Cosmological Inference from within the Peculiar Local Universe
by Roya Mohayaee, Mohamed Rameez and Subir Sarkar
Universe 2024, 10(5), 209; https://doi.org/10.3390/universe10050209 (registering DOI) - 07 May 2024
Abstract
The existence of ‘peculiar’ velocities due to the formation of cosmic structure marks a point of discord between the real universe and the usually assumed Friedmann–Lemaítre–Robertson–Walker metric, which accomodates only the smooth Hubble expansion on large scales. In the standard ΛCDM model [...] Read more.
The existence of ‘peculiar’ velocities due to the formation of cosmic structure marks a point of discord between the real universe and the usually assumed Friedmann–Lemaítre–Robertson–Walker metric, which accomodates only the smooth Hubble expansion on large scales. In the standard ΛCDM model framework, Type Ia supernovae data are routinely “corrected” for the peculiar velocities of both the observer and the supernova host galaxies relative to the cosmic rest frame, in order to infer evidence for acceleration of the expansion rate from their Hubble diagram. However, observations indicate a strong, coherent local bulk flow that continues outward without decaying out to a redshift z0.1, contrary to the ΛCDM expectation. By querying the halo catalogue of the Dark Sky Hubble-volume N-body simulation, we find that an observer placed in an unusual environment like our local universe should see correlations between supernovae in the JLA catalogue that are 2–8 times stronger than seen by a typical or Copernican observer. This accounts for our finding that peculiar velocity corrections have a large impact on the value of the cosmological constant inferred from supernova data. We also demonstrate that local universe-like observers will infer a downward biased value of the clustering parameter S8 from comparing the density and velocity fields. More realistic modelling of the peculiar local universe is thus essential for correctly interpreting cosmological data. Full article
(This article belongs to the Special Issue The Large-Scale Structure of the Universe: Theory and Observation)
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16 pages, 4028 KiB  
Article
Zagros Grass Index—A New Vegetation Index to Enhance Fire Fuel Mapping: A Case Study in the Zagros Mountains
by Iraj Rahimi, Lia Duarte and Ana Cláudia Teodoro
Sustainability 2024, 16(10), 3900; https://doi.org/10.3390/su16103900 (registering DOI) - 07 May 2024
Abstract
Annually, the oak forests of the Zagros Mountains chains in western Iran and northeastern Iraq face recurring challenges posed by forest fires, particularly in the Kurdo–Zagrosian forests in western Iran and northeastern Iraq. Assessing fire susceptibility relies significantly on vegetation conditions. Integrating in [...] Read more.
Annually, the oak forests of the Zagros Mountains chains in western Iran and northeastern Iraq face recurring challenges posed by forest fires, particularly in the Kurdo–Zagrosian forests in western Iran and northeastern Iraq. Assessing fire susceptibility relies significantly on vegetation conditions. Integrating in situ data, Remote Sensing (RS) data, and Geographical Information Systems (GIS) integration presents a cost-effective and precise approach to capturing environmental conditions before, during, and after fire events, minimizing the need for extensive fieldwork. This study refines and applies the Zagros Grass Index (ZGI), a local vegetation index tailored to discern between grass-covered surfaces and tree canopies in Zagros forests, identifying the grass masses as the most flammable fuel type. Utilizing the Moderate Resolution Imaging Spectroradiometer (MODIS) Normalized Difference Vegetation Index (NDVI) product as input from 2013 to 2022, the ZGI aims to mitigate the influence of tree canopies by isolating NDVI values solely attributable to grass cover. By incorporating phenological characteristics of forest trees and grass species, the ZGI outperforms NDVI in mapping grass-covered areas crucial for the study region’s fire susceptibility assessment. Results demonstrate a substantial overlap between ZGI-based maps and recorded fire occurrences, validating the efficacy of the index in fire susceptibility estimation. Full article
18 pages, 1298 KiB  
Article
Position Correction Control of Permanent-Magnet Brushless Motor Based on Commutation-Interval Current Symmetry
by Yongwu Guo, Yun Zhang and Xiaowei Li
World Electr. Veh. J. 2024, 15(5), 203; https://doi.org/10.3390/wevj15050203 (registering DOI) - 07 May 2024
Abstract
With the needs of environmental protection and the adjustment of energy structure, new energy vehicles are playing an increasingly important role in the field of transportation today. The permanent-magnet brushless direct-current motor has the characteristics of high efficiency, and can be used in [...] Read more.
With the needs of environmental protection and the adjustment of energy structure, new energy vehicles are playing an increasingly important role in the field of transportation today. The permanent-magnet brushless direct-current motor has the characteristics of high efficiency, and can be used in the drive system of new energy vehicles or other auxiliary equipment. In the control process of the permanent-magnet brushless direct-current motor, based on a three-Hall position sensor, due to various factors, there are some errors in the Hall position signal, which must be corrected by appropriate measures. In this paper, the relationship between the position deviation in the commutation interval and the non-commutation-phase current is analyzed, and the current expressions in three different states are given. A new closed-loop compensation strategy for correcting the inaccurate commutation caused by the Hall signal error is proposed. Taking the position of a 30° electrical angle before and after the phase-change point as the H point, realizing the current symmetry within the 30° interval around the H point as the target and the sum of the slopes of the tangent lines at the two points symmetrical within the β (0 < β < 30) electrical angle around the H point as the deviation, a proportional-integral regulator is designed to correct the phase error of the phase-change signal. Finally, it is verified by experiments that the closed-loop compensation strategy proposed in this paper can effectively compensate the phase deviation of the commutation signal at a speed of about 2000 r/min, which improves the working efficiency of the motor to a certain extent. Full article
22 pages, 1984 KiB  
Article
Zero-Shot Sketch-Based Remote-Sensing Image Retrieval Based on Multi-Level and Attention-Guided Tokenization
by Bo Yang, Chen Wang, Xiaoshuang Ma, Beiping Song, Zhuang Liu and Fangde Sun
Remote Sens. 2024, 16(10), 1653; https://doi.org/10.3390/rs16101653 (registering DOI) - 07 May 2024
Abstract
Effectively and efficiently retrieving images from remote-sensing databases is a critical challenge in the realm of remote-sensing big data. Utilizing hand-drawn sketches as retrieval inputs offers intuitive and user-friendly advantages, yet the potential of multi-level feature integration from sketches remains underexplored, leading to [...] Read more.
Effectively and efficiently retrieving images from remote-sensing databases is a critical challenge in the realm of remote-sensing big data. Utilizing hand-drawn sketches as retrieval inputs offers intuitive and user-friendly advantages, yet the potential of multi-level feature integration from sketches remains underexplored, leading to suboptimal retrieval performance. To address this gap, our study introduces a novel zero-shot, sketch-based retrieval method for remote-sensing images, leveraging multi-level feature extraction, self-attention-guided tokenization and filtering, and cross-modality attention update. This approach employs only vision information and does not require semantic knowledge concerning the sketch and image. It starts by employing multi-level self-attention guided feature extraction to tokenize the query sketches, as well as self-attention feature extraction to tokenize the candidate images. It then employs cross-attention mechanisms to establish token correspondence between these two modalities, facilitating the computation of sketch-to-image similarity. Our method significantly outperforms existing sketch-based remote-sensing image retrieval techniques, as evidenced by tests on multiple datasets. Notably, it also exhibits robust zero-shot learning capabilities in handling unseen categories and strong domain adaptation capabilities in handling unseen novel remote-sensing data. The method’s scalability can be further enhanced by the pre-calculation of retrieval tokens for all candidate images in a database. This research underscores the significant potential of multi-level, attention-guided tokenization in cross-modal remote-sensing image retrieval. For broader accessibility and research facilitation, we have made the code and dataset used in this study publicly available online. Full article
16 pages, 1387 KiB  
Article
Fracture Resistance of a Bone-Level Two-Piece Zirconia Oral Implant System—The Influence of Artificial Loading and Hydrothermal Aging
by Ralf J. Kohal, Ellen Riesterer, Kirstin Vach, Sebastian B. M. Patzelt, Aljaž Iveković, Lara Einfalt, Andraž Kocjan and Anna-Lena Hillebrecht
J. Funct. Biomater. 2024, 15(5), 122; https://doi.org/10.3390/jfb15050122 (registering DOI) - 07 May 2024
Abstract
Preclinical and clinical research on two-piece zirconia implants are warranted. Therefore, we evaluated the in vitro fracture resistance of such a zirconia oral implant system. The present study comprised 32 two-piece zirconia implants and abutments attached to the implants using a titanium ( [...] Read more.
Preclinical and clinical research on two-piece zirconia implants are warranted. Therefore, we evaluated the in vitro fracture resistance of such a zirconia oral implant system. The present study comprised 32 two-piece zirconia implants and abutments attached to the implants using a titanium (n = 16) or a zirconia abutment screw (n = 16). Both groups were subdivided (n = 8): group T-0 comprised implants with a titanium abutment screw and no artificial loading; group T-HL was the titanium screw group exposed to hydro-thermomechanical loading in a chewing simulator; group Z-0 was the zirconia abutment screw group with no artificial loading; and group Z-HL comprised the zirconia screw group with hydro-thermomechanical loading. Groups T-HL and Z-HL were loaded with 98 N and aged in 85 °C hot water for 107 chewing cycles. All samples were loaded to fracture. Kruskal–Wallis tests were executed to assess the loading/bending moment group differences. The significance level was established at a probability of 0.05. During the artificial loading, there was a single occurrence of an implant fracture. The mean fracture resistances measured in a universal testing machine were 749 N for group T-0, 828 N for group Z-0, 652 N for group T-HL, and 826 N for group Z-HL. The corresponding bending moments were as follows: group T-0, 411 Ncm; group Z-0, 452 Ncm; group T-HL, 356 Ncm; and group Z-HL, 456 Ncm. There were no statistically significant differences found between the experimental groups. Therefore, the conclusion was that loading and aging did not diminish the fracture resistance of the evaluated implant system. Full article
(This article belongs to the Special Issue Advanced Biomaterials and Oral Implantology—Volume II)
23 pages, 3455 KiB  
Article
Research on the Performance of Lightweight Prefabricated Concrete Stairs with a Special-Shaped Hollow Landing Slab
by Yilin Wang, Dapeng Sheng and Yu Wang
Buildings 2024, 14(5), 1314; https://doi.org/10.3390/buildings14051314 (registering DOI) - 07 May 2024
Abstract
In order to further improve the technical advantages of lightweight prefabricated concrete stairs, a kind of prefabricated stair system using a special-shaped hollow landing slab was proposed. Based on the detailed structural composition display, the design method for the main components (prefabricated flight [...] Read more.
In order to further improve the technical advantages of lightweight prefabricated concrete stairs, a kind of prefabricated stair system using a special-shaped hollow landing slab was proposed. Based on the detailed structural composition display, the design method for the main components (prefabricated flight and special-shaped prefabricated hollow landing slab) was proposed and a design application example was provided. Furthermore, specialized experimental and numerical simulation studies were conducted on the key component—the special-shaped prefabricated hollow landing slab. The research results indicated that this new kind of lightweight prefabricated concrete stairs using a special-shaped prefabricated hollow landing slab has reasonable construction, an effective design method, a clear force transmission mechanism, moderate component weight, and high transportation and installation convenience. Full article
(This article belongs to the Section Building Structures)
57 pages, 5226 KiB  
Review
Design, Manufacturing, and Analysis of Periodic Three-Dimensional Cellular Materials for Energy Absorption Applications: A Critical Review
by Autumn R. Bernard and Mostafa S. A. ElSayed
Materials 2024, 17(10), 2181; https://doi.org/10.3390/ma17102181 (registering DOI) - 07 May 2024
Abstract
Cellular materials offer industries the ability to close gaps in the material selection design space with properties not otherwise achievable by bulk, monolithic counterparts. Their superior specific strength, stiffness, and energy absorption, as well as their multi-functionality, makes them desirable for a wide [...] Read more.
Cellular materials offer industries the ability to close gaps in the material selection design space with properties not otherwise achievable by bulk, monolithic counterparts. Their superior specific strength, stiffness, and energy absorption, as well as their multi-functionality, makes them desirable for a wide range of applications. The objective of this paper is to compile and present a review of the open literature focusing on the energy absorption of periodic three-dimensional cellular materials. The review begins with the methodical cataloging of qualitative and quantitative elements from 100 papers in the available literature and then provides readers with a thorough overview of the state of this research field, discussing areas such as parent material(s), manufacturing methods, cell topologies, cross-section shapes for truss topologies, analysis methods, loading types, and test strain rates. Based on these collected data, areas of great and limited research are identified and future avenues of interest are suggested for the continued maturation and growth of this field, such as the development of a consistent naming and classification system for topologies; the creation of test standards considering additive manufacturing processes; further investigation of non-uniform and non-cylindrical struts on the performance of truss lattices; and further investigation into the performance of lattice materials under the impact of non-flat surfaces and projectiles. Finally, the numerical energy absorption (by mass and by volume) data of 76 papers are presented across multiple property selection charts, highlighting various materials, manufacturing methods, and topology groups. While there are noticeable differences at certain densities, the graphs show that the categorical differences within those groups have large overlap in terms of energy absorption performance and can be referenced to identify areas for further investigation and to help in the preliminary design process by researchers and industry professionals alike. Full article
(This article belongs to the Special Issue Mechanical Behavior and Numerical Simulation of Sandwich Composites)
17 pages, 1175 KiB  
Article
Rapid and Sensitive Detection of Inactivated SARS-CoV-2 Virus via Fiber-Optic and Electrochemical Impedance Spectroscopy Based Aptasensors
by Can Xiao, Nan Wang, Yuechao Zhao, Xuemei Liu, Hui Li, Aixue Huang, Lin Wang, Xinhui Lou, Bo Gao and Ningsheng Shao
Biosensors 2024, 14(5), 231; https://doi.org/10.3390/bios14050231 (registering DOI) - 07 May 2024
Abstract
The development of rapid detection tools for viruses is vital for the prevention of pandemics and biothreats. Aptamers that target inactivated viruses are attractive for sensors due to their improved biosafety. Here, we evaluated a DNA aptamer (named as 6.9) that specifically binds [...] Read more.
The development of rapid detection tools for viruses is vital for the prevention of pandemics and biothreats. Aptamers that target inactivated viruses are attractive for sensors due to their improved biosafety. Here, we evaluated a DNA aptamer (named as 6.9) that specifically binds to the inactivated SARS-CoV-2 virus with a low dissociation constant (KD = 9.6 nM) for the first time. Based on aptamer 6.9, we developed a fiber-optic evanescent wave (FOEW) biosensor. Inactivated SARS-CoV-2 and the Cy5.5-tagged short complementary strand competitively bound with the aptamer immobilized on the surface of the sensor. The detection of the inactivated SARS-CoV-2 virus was realized within six minutes with a limit of detection (LOD, S/N = 3) of 740 fg/mL. We also developed an electrochemical impedance aptasensor which exhibited an LOD of 5.1 fg/mL and high specificity. We further demonstrated that the LODs of the FOEW and electrochemical impedance aptasensors were, respectively, more than 1000 and 100,000 times lower than those of commercial colloidal gold test strips. We foresee that the facile aptamer isolation process and sensor design can be easily extended for the detection of other inactivated viruses. Full article
(This article belongs to the Section Biosensors and Healthcare)
16 pages, 2901 KiB  
Article
Piezoelectric Yield of Single Electrospun Poly(acrylonitrile) Ultrafine Fibers Studied by Piezoresponse Force Microscopy and Numerical Simulations
by Margherita Montorsi, Lorenzo Zavagna, Lorenzo Scarpelli, Bahareh Azimi, Simone Capaccioli, Serena Danti and Massimiliano Labardi
Polymers 2024, 16(10), 1305; https://doi.org/10.3390/polym16101305 (registering DOI) - 07 May 2024
Abstract
Quantitative converse piezoelectric coefficient (d33) mapping of polymer ultrafine fibers of poly(acrylonitrile) (PAN), as well as of poly(vinylidene fluoride) (PVDF) as a reference material, obtained by rotating electrospinning, was carried out by piezoresponse force microscopy in the constant-excitation frequency-modulation mode [...] Read more.
Quantitative converse piezoelectric coefficient (d33) mapping of polymer ultrafine fibers of poly(acrylonitrile) (PAN), as well as of poly(vinylidene fluoride) (PVDF) as a reference material, obtained by rotating electrospinning, was carried out by piezoresponse force microscopy in the constant-excitation frequency-modulation mode (CE-FM-PFM). PFM mapping of single fibers reveals their piezoelectric activity and provides information on its distribution along the fiber length. Uniform behavior is typically observed on a length scale of a few micrometers. In some cases, variations with sinusoidal dependence along the fiber are reported, compatibly with a possible twisting around the fiber axis. The observed features of the piezoelectric yield have motivated numerical simulations of the surface displacement in a piezoelectric ultrafine fiber concerned by the electric field generated by biasing of the PFM probe. Uniform alignment of the piezoelectric axis along the fiber would comply with the uniform but strongly variable values observed, and sinusoidal variations were occasionally found on the fibers laying on the conductive substrate. Furthermore, in the latter case, numerical simulations show that the piezoelectric tensor’s shear terms should be carefully considered in estimations since they may provide a remarkably different contribution to the overall deformation profile. Full article
21 pages, 4795 KiB  
Article
Silver Complexes of Miconazole and Metronidazole: Potential Candidates for Melanoma Treatment
by Małgorzata Fabijańska, Agnieszka J. Rybarczyk-Pirek, Justyna Dominikowska, Karolina Stryjska, Dominik Żyro, Magdalena Markowicz-Piasecka, Małgorzata Iwona Szynkowska-Jóźwik, Justyn Ochocki and Joanna Sikora
Int. J. Mol. Sci. 2024, 25(10), 5081; https://doi.org/10.3390/ijms25105081 (registering DOI) - 07 May 2024
Abstract
Melanoma, arguably the deadliest form of skin cancer, is responsible for the majority of skin-cancer-related fatalities. Innovative strategies concentrate on new therapies that avoid the undesirable effects of pharmacological or medical treatment. This article discusses the chemical structures of [(MTZ)2AgNO3 [...] Read more.
Melanoma, arguably the deadliest form of skin cancer, is responsible for the majority of skin-cancer-related fatalities. Innovative strategies concentrate on new therapies that avoid the undesirable effects of pharmacological or medical treatment. This article discusses the chemical structures of [(MTZ)2AgNO3], [(MTZ)2Ag]2SO4, [Ag(MCZ)2NO3], [Ag(MCZ)2BF4], [Ag(MCZ)2SbF6] and [Ag(MCZ)2ClO4] (MTZ—metronidazole; MCZ—miconazole) silver(I) compounds and the possible relationship between the molecules and their cytostatic activity against melanoma cells. Molecular Hirshfeld surface analysis and computational methods were used to examine the possible association between the structure and anticancer activity of the silver(I) complexes and compare the cytotoxicity of the silver(I) complexes of metronidazole and miconazole with that of silver(I) nitrate, cisplatin, metronidazole and miconazole complexes against A375 and BJ cells. Additionally, these preliminary biological studies found the greatest IC50 values against the A375 line were demonstrated by [Ag(MCZ)2NO3] and [(MTZ)2AgNO3]. The compound [(MTZ)2AgNO3] was three-fold more toxic to the A375 cells than the reference (cisplatin) and 15 times more cytotoxic against the A375 cells than the normal BJ cells. Complexes of metronidazole with Ag(I) are considered biocompatible at a concentration below 50 µmol/L. Full article
(This article belongs to the Special Issue Recent Advances in Anti-Cancer Drugs)
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13 pages, 2072 KiB  
Article
Electronically Temperature-Dependent Interplay between He and Trivacancy in Tungsten Plasma-Facing Materials
by Zhao-Zhong Fu and Bi-Cai Pan
Materials 2024, 17(10), 2182; https://doi.org/10.3390/ma17102182 (registering DOI) - 07 May 2024
Abstract
Both microvoids and helium (He) impurities are widely present in tungsten (W) plasma-facing materials (PFMs), where the interaction between microvoids and He atoms has led to the intriguing development of microvoids. In this paper, we comprehensively investigated the interaction between He atoms and [...] Read more.
Both microvoids and helium (He) impurities are widely present in tungsten (W) plasma-facing materials (PFMs), where the interaction between microvoids and He atoms has led to the intriguing development of microvoids. In this paper, we comprehensively investigated the interaction between He atoms and trivacancy (V3), a fundamental microvoid in W-PFMs, at the level of tight-binding theory. Our study showed that He atoms can catalyze the decomposition of the original V3 or facilitate its transformation into another V3 variant. We propose that a He atom near the V3 defect induces significant changes in the distribution of d-electron charges within the W atoms lining the inner wall of the V3 defect, making the W atom nearest to this He atom cationic and the other W atoms anionic. The attractive interaction between them promotes the decomposition and deformation of V3. As electronic excitation increases, the ionization of W atoms on the V3 wall gradually intensifies, thereby enhancing the cationic characteristics of the W atoms closest to the He atom. This process also prompts other W atoms to shift from anions to cations, leading to a transition in the electrostatic interactions between them from attraction to repulsion. This transformation, driven by electronic excitation, plays a significant inhibitory role in the decomposition and deformation of V3. Full article
(This article belongs to the Topic Advances in Computational Materials Sciences)
17 pages, 1185 KiB  
Review
Current Status of Research on Wildland Fire Impacts on Soil Environment and Soil Organisms and Hotspots Visualization Analysis
by Zhichao Cheng, Song Wu, Dan Wei, Hong Pan, Xiaoyu Fu, Xinming Lu and Libin Yang
Fire 2024, 7(5), 163; https://doi.org/10.3390/fire7050163 (registering DOI) - 07 May 2024
Abstract
Ecosystems are frequently disturbed by fires that have an important impact on the soil environment and the composition of soil organisms. In order to provide a baseline for the current research and identify trends on the effects of wildland fire on soil environment [...] Read more.
Ecosystems are frequently disturbed by fires that have an important impact on the soil environment and the composition of soil organisms. In order to provide a baseline for the current research and identify trends on the effects of wildland fire on soil environment and biological changes, the available literature was identified from the Web of Science database, covering the period from 1998/1998/1999 (the year of the earliest publication in this field) to 2023. A bibliometric analysis was performed and the data were visually displayed for the number of publications, countries, authors, research institutions, and keywords representing research hotspots. Specifically, the effects of wildland fire on the soil environment, on soil microorganisms and on soil fauna were analyzed. The results show that the annual number of publications describing effects of wildland fire on the soil environment and on soil microorganisms are increasing over time, while those describing effects on soil fauna are fewer and their number remains constant. The largest number of papers originate from the United States, with the United States Department of Agriculture as the research institution with the largest output. The three authors with the largest number of publications are Stefan H. Doerr, Manuel Esteban Lucas-Borja and Jan Jacob Keizer. The research hotspots, as identified by keywords, are highly concentrated on wildfire, fire, organic matter, and biodiversity, amongst others. This study comprehensively analyzes the current situation of the research on the effects of wildland fire on changes in the soil environment and organisms, and provides reference for relevant scientific researchers in this trend and future research hotspots. Full article
(This article belongs to the Special Issue Effects of Fires on Forest Ecosystems)
13 pages, 832 KiB  
Article
Quality Characteristics of Raspberry By-Products for Sustainable Production
by Audrone Ispiryan, Ingrida Kraujutiene and Jonas Viskelis
Foods 2024, 13(10), 1436; https://doi.org/10.3390/foods13101436 (registering DOI) - 07 May 2024
Abstract
Raspberry seeds are a by-product of berries, both from their primary processing, such as in juice production, and secondary processing, such as in oil extraction. These seeds contain plenty of valuable components such as crude fiber, proteins, fats, and vitamins. Quality characterization is [...] Read more.
Raspberry seeds are a by-product of berries, both from their primary processing, such as in juice production, and secondary processing, such as in oil extraction. These seeds contain plenty of valuable components such as crude fiber, proteins, fats, and vitamins. Quality characterization is the initial step toward using these seeds as a sustainable and functional food. The aim of studying raspberry seeds’ quality profile, both before oil extraction and after different processing methods (supercritical CO2, subcritical CO2, cold pressing, and hexane solvent), is to point out the benefits of this by-product and to raise consumer awareness about their health and well-being benefits. This study provides evidence that raspberry seeds have good physical parameters for use in other products as a functional food enrichment ingredient, such as in baked goods, offering considerable health benefits due to their high nutrient content. The weights, peroxide values, moisture content, nutritional energy values, and colors were determined before oil extraction to give initial seed values. The nutrient content and amounts of macroelements, P, K, Ca, and Mg, as well as microelements, B, Zn, Cu, Fe, and Mn, were determined in the tested variety ‘Polka’, both before and after oil extractions and using different methods. The raspberry seeds’ moisture was 9.2%, their peroxide content was 5.64 mEq/kg, their nutritional value was 475.25 Kcal., and their total weight was 2.17 mg (1000 units). The seeds contain 7.4% protein, 22.1% crude fiber, 11.0% crude fat and oil, and 2.8% sugar. We determined how different oil extraction methods influence the nutrient, micro-, and macro-component values. We concluded that the seeds contained the highest manganese (45.3 mg/kg), iron (29.2 mg/kg), and zinc (17.4 mg/kg) contents and the lowest content of copper (5.1 mg/kg). This research shows that raspberry seeds represent a potential natural food ingredient, and after oil extraction with subcritical or supercritical CO2 or cold pressing, they can be used as a sustainable and functional food. Full article
(This article belongs to the Section Food Security and Sustainability)
11 pages, 1671 KiB  
Article
Determination of Microplastics in Omega-3 Oil Supplements
by Moonhae Kim, Juyang Kim, Seulah Park, Dowoon Kim, Jaehak Jung and Dongha Cho
Foods 2024, 13(10), 1434; https://doi.org/10.3390/foods13101434 (registering DOI) - 07 May 2024
Abstract
Microplastics (MPs) are ubiquitous in the environment, posing a threat to ecosystems and causing increasing concerns regarding their impacts on the human body through exposure. However, there has been limited research on the presence of MPs in functional foods, despite them being consumed [...] Read more.
Microplastics (MPs) are ubiquitous in the environment, posing a threat to ecosystems and causing increasing concerns regarding their impacts on the human body through exposure. However, there has been limited research on the presence of MPs in functional foods, despite them being consumed for health improvement. This study aimed to investigate MP occurrence in various omega-3 oils and oil products in the Korean market and its relation to the source of raw material or manufacture. MPs were investigated in omega-3 capsules and raw oil, sourced from both plant-based (PB) and animal-based (AB) sources. We developed a method of direct filtration with acetone washing for collecting and characterizing MPs larger than 5 μm using micro-Raman spectroscopy. The average number of MPs by mass was found to be 1.2 ± 1.7 MPs/g for PB raw oil, 2.2 ± 1.7 MPs/g for AB raw oil, 3.5 ± 3.9 MPs/g for PB capsule oil, and 10.6 ± 8.9 MPs/g for AB capsule oil. Polypropylene and polyethylene terephthalate were the major MP species (83–95%) found in omega-3 oil. The proportions based on size range remained consistent across all groups, with a trend of being detected at higher rates as the size decreased. The results reveal that the main reason for the MP contamination of omega-3 oil is not the source of raw material but the manufacturing and packaging process. Full article
(This article belongs to the Section Food Toxicology)
12 pages, 1497 KiB  
Article
Fabrication of Ternary Titanium Dioxide/Polypyrrole/Phosphorene Nanocomposite for Supercapacitor Electrode Applications
by Seungho Ha and Keun-Young Shin
Molecules 2024, 29(10), 2172; https://doi.org/10.3390/molecules29102172 (registering DOI) - 07 May 2024
Abstract
In this paper, we report a titanium dioxide/polypyrrole/phosphorene (TiO2/PPy/phosphorene) nanocomposite as an active material for supercapacitor electrodes. Black phosphorus (BP) was fabricated by ball milling to induce a phase transition from red phosphorus, and urea-functionalized phosphorene (urea-FP) was obtained by urea-assisted [...] Read more.
In this paper, we report a titanium dioxide/polypyrrole/phosphorene (TiO2/PPy/phosphorene) nanocomposite as an active material for supercapacitor electrodes. Black phosphorus (BP) was fabricated by ball milling to induce a phase transition from red phosphorus, and urea-functionalized phosphorene (urea-FP) was obtained by urea-assisted ball milling of BP, followed by sonication. TiO2/PPy/phosphorene nanocomposites can be prepared via chemical oxidative polymerization, which has the advantage of mass production for a one-pot synthesis. The specific capacitance of the ternary nanocomposite was 502.6 F g−1, which was higher than those of the phosphorene/PPy (286.25 F g−1) and TiO2/PPy (150 F g−1) nanocomposites. The PPy fully wrapped around the urea-FP substrate provides an electron transport pathway, resulting in the enhanced electrical conductivity of phosphorene. Furthermore, the assistance of anatase TiO2 nanoparticles enhanced the structural stability and also improved the specific capacitance of the phosphorene. To the best of our knowledge, this is the first report on the potential of phosphorene hybridized with conducting polymers and metal oxides for practical supercapacitor applications. Full article
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26 pages, 5102 KiB  
Article
Research on Crack Propagation of Nitrate Ester Plasticized Polyether Propellant: Experiments and Simulation
by Hanwen Liu, Jiangning Wang and Xiaolong Fu
Materials 2024, 17(10), 2180; https://doi.org/10.3390/ma17102180 (registering DOI) - 07 May 2024
Abstract
To understand the fracture properties of the nitrate ester plasticized polyether (NEPE) propellant, single-edge notched tension (SENT) tests were carried out at room temperature (20 °C) under different tensile rates (10–500 mm/min). The mechanical response, crack morphology, evolution path, and crack propagation velocity [...] Read more.
To understand the fracture properties of the nitrate ester plasticized polyether (NEPE) propellant, single-edge notched tension (SENT) tests were carried out at room temperature (20 °C) under different tensile rates (10–500 mm/min). The mechanical response, crack morphology, evolution path, and crack propagation velocity during the fracture process were studied using a combination of a drawing machine and a high-speed camera. The mode I critical stress intensity factor KIc was calculated to analyze the tensile fracture toughness of the NEPE propellant, and a criterion related to KIc was proposed as a means of determining whether the solid rocket motors can normally work. The experimental results demonstrated that the NEPE propellant exhibited blunting fracture phenomena during crack propagation, resulting in fluctuating crack propagation velocity. The fracture toughness of the NEPE propellant exhibited clear rate dependence. When the tensile rate increased from 10 mm/min to 500 mm/min, the magnitude of the critical stress intensity factor increased by 62.3%. Moreover, numerical studies based on bond-based peridynamic (BBPD) were performed by modeling the fracture process of the NEPE propellant, including the crack propagation speed and the load–displacement curve of the NEPE propellant. The simulation results were then compared with the experiments. Full article

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