The 2023 MDPI Annual Report has
been released!
 
13 pages, 778 KiB  
Article
Prediction of Icing on Wind Turbines Based on SCADA Data via Temporal Convolutional Network
by Yujie Zhang, Nasser Kehtarnavaz, Mario Rotea and Teja Dasari
Energies 2024, 17(9), 2175; https://doi.org/10.3390/en17092175 (registering DOI) - 02 May 2024
Abstract
Icing on the blades of wind turbines during winter seasons causes a reduction in power and revenue losses. The prediction of icing before it occurs has the potential to enable mitigating actions to reduce ice accumulation. This paper presents a framework for the [...] Read more.
Icing on the blades of wind turbines during winter seasons causes a reduction in power and revenue losses. The prediction of icing before it occurs has the potential to enable mitigating actions to reduce ice accumulation. This paper presents a framework for the prediction of icing on wind turbines based on Supervisory Control and Data Acquisition (SCADA) data without requiring the installation of any additional icing sensors on the turbines. A Temporal Convolutional Network is considered as the model to predict icing from the SCADA data time series. All aspects of the icing prediction framework are described, including the necessary data preprocessing, the labeling of SCADA data for icing conditions, the selection of informative icing features or variables in SCADA data, and the design of a Temporal Convolutional Network as the prediction model. Two performance metrics to evaluate the prediction outcome are presented. Using SCADA data from an actual wind turbine, the model achieves an average prediction accuracy of 77.6% for future times of up to 48 h. Full article
(This article belongs to the Topic Advances in Wind Energy Technology)
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32 pages, 8970 KiB  
Review
Defects and Defect Passivation in Perovskite Solar Cells
by Zhanwei Wang, Hongli Gao, Dandan Wu, Junhua Meng, Jinxiang Deng and Min Cui
Molecules 2024, 29(9), 2104; https://doi.org/10.3390/molecules29092104 (registering DOI) - 02 May 2024
Abstract
Perovskite solar cells have made significant strides in recent years. However, there are still challenges in terms of photoelectric conversion efficiency and long-term stability associated with perovskite solar cells. The presence of defects in perovskite materials is one of the important influencing factors [...] Read more.
Perovskite solar cells have made significant strides in recent years. However, there are still challenges in terms of photoelectric conversion efficiency and long-term stability associated with perovskite solar cells. The presence of defects in perovskite materials is one of the important influencing factors leading to subpar film quality. Adopting additives to passivate defects within perovskite materials is an effective approach. Therefore, we first discuss the types of defects that occur in perovskite materials and the mechanisms of their effect on performance. Then, several types of additives used in perovskite solar cells are discussed, including ionic compounds, organic molecules, polymers, etc. This review provides guidance for the future development of more sustainable and effective additives to improve the performance of solar cells. Full article
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12 pages, 369 KiB  
Article
Asymptotic Behavior of Some Differential Inequalities with Mixed Delays and Their Applications
by Axiu Shu, Xiaoliang Li and Bo Du
Axioms 2024, 13(5), 302; https://doi.org/10.3390/axioms13050302 (registering DOI) - 02 May 2024
Abstract
In this paper, we focus on the asymptotic stability of the trajectories governed by the differential inequalities with mixed delays using the fixed-point theorem. It is interesting that the Halanay inequality is a special case of the differential inequality studied in this paper. [...] Read more.
In this paper, we focus on the asymptotic stability of the trajectories governed by the differential inequalities with mixed delays using the fixed-point theorem. It is interesting that the Halanay inequality is a special case of the differential inequality studied in this paper. Our results generalize and improve the existing results on Halanay inequality. Finally, three numerical examples are utilized to illustrate the effectiveness of the obtained results. Full article
(This article belongs to the Special Issue Research on Fixed Point Theory and Application)
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14 pages, 2707 KiB  
Article
Ternary Polymer Solar Cells: Impact of Non-Fullerene Acceptors on Optical and Morphological Properties
by Quentin Eynaud, Tomoyuki Koganezawa, Hidehiro Sekimoto, Mohamed el Amine Kramdi, Gilles Quéléver, Olivier Margeat, Jörg Ackermann, Noriyuki Yoshimoto and Christine Videlot-Ackermann
Electronics 2024, 13(9), 1752; https://doi.org/10.3390/electronics13091752 (registering DOI) - 02 May 2024
Abstract
Ternary organic solar cells contain a single three-component photoactive layer with a wide absorption window, achieved without the need for multiple stacking. However, adding a third component into a well-known binary blend can influence the energetics, optical window, charge carrier transport, crystalline order [...] Read more.
Ternary organic solar cells contain a single three-component photoactive layer with a wide absorption window, achieved without the need for multiple stacking. However, adding a third component into a well-known binary blend can influence the energetics, optical window, charge carrier transport, crystalline order and conversion efficiency. In the form of binary blends, the low-bandgap regioregular polymer donor poly(3-hexylthiophene-2,5-diyl), known as P3HT, is combined with the acceptor PC61BM, an inexpensive fullerene derivative. Two different non-fullerene acceptors (ITIC and eh-IDTBR) are added to this binary blend to form ternary blends. A systematic comparison between binary and ternary systems was carried out as a function of the thermal annealing temperature of organic layers (100 °C and 140 °C). The power conversion efficiency (PCE) is improved due to increased fill factor (FF) and open-circuit voltage (Voc) for thermal-annealed ternary blends at 140 °C. The transport properties of electrons and holes were investigated in binary and ternary blends following a Space-Charge-Limited Current (SCLC) protocol. A favorable balanced hole–electron mobility is obtained through the incorporation of either ITIC or eh-IDTBR. The charge transport behavior is correlated with the bulk heterojunction (BHJ) morphology deduced from atomic force microscopy (AFM), contact water angle (CWA) measurement and 2D grazing-incidence X-ray diffractometry (2D-GIXRD). Full article
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14 pages, 3322 KiB  
Article
A Fruit-Expressed MYB Transcription Factor Regulates Anthocyanin Biosynthesis in Atropa belladonna
by Xiaoqiang Liu, Tengfei Zhao, Lina Yuan, Fei Qiu, Yueli Tang, Dan Li, Fangyuan Zhang, Lingjiang Zeng, Chunxian Yang, Mohammad Mahmoud Nagdy, Zun Lai Lai Htun, Xiaozhong Lan, Min Chen, Zhihua Liao and Yan Li
Int. J. Mol. Sci. 2024, 25(9), 4963; https://doi.org/10.3390/ijms25094963 (registering DOI) - 02 May 2024
Abstract
Anthocyanins are water-soluble flavonoid pigments that play a crucial role in plant growth and metabolism. They serve as attractants for animals by providing plants with red, blue, and purple pigments, facilitating pollination and seed dispersal. The fruits of solanaceous plants, tomato (Solanum [...] Read more.
Anthocyanins are water-soluble flavonoid pigments that play a crucial role in plant growth and metabolism. They serve as attractants for animals by providing plants with red, blue, and purple pigments, facilitating pollination and seed dispersal. The fruits of solanaceous plants, tomato (Solanum lycopersicum) and eggplant (Solanum melongena), primarily accumulate anthocyanins in the fruit peels, while the ripe fruits of Atropa belladonna (Ab) have a dark purple flesh due to anthocyanin accumulation. In this study, an R2R3-MYB transcription factor (TF), AbMYB1, was identified through association analysis of gene expression and anthocyanin accumulation in different tissues of A. belladonna. Its role in regulating anthocyanin biosynthesis was investigated through gene overexpression and RNA interference (RNAi). Overexpression of AbMYB1 significantly enhanced the expression of anthocyanin biosynthesis genes, such as AbF3H, AbF35H, AbDFR, AbANS, and Ab3GT, leading to increased anthocyanin production. Conversely, RNAi-mediated suppression of AbMYB1 resulted in decreased expression of most anthocyanin biosynthesis genes, as well as reduced anthocyanin contents in A. belladonna. Overall, AbMYB1 was identified as a fruit-expressed R2R3-MYB TF that positively regulated anthocyanin biosynthesis in A. belladonna. This study provides valuable insights into the regulation of anthocyanin biosynthesis in Solanaceae plants, laying the foundation for understanding anthocyanin accumulation especially in the whole fruits of solanaceous plants. Full article
(This article belongs to the Special Issue Plant Omics: Sensing, Signaling, Regulation and Homeostasis)
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28 pages, 7235 KiB  
Review
Lithium Silicate-Based Glass Ceramics in Dentistry: A Narrative Review
by Hanan Al-Johani, Julfikar Haider, Julian Satterthwaite and Nick Silikas
Prosthesis 2024, 6(3), 478-505; https://doi.org/10.3390/prosthesis6030034 (registering DOI) - 02 May 2024
Abstract
Considering the rapid evolution of lithium silicate-based glass ceramics (LSCs) in dentistry, this review paper aims to present an updated overview of the recently introduced commercial novel LSCs. The clinical and in vitro English-language literature relating to the microstructure, manufacturing, strengthening, properties, surface [...] Read more.
Considering the rapid evolution of lithium silicate-based glass ceramics (LSCs) in dentistry, this review paper aims to present an updated overview of the recently introduced commercial novel LSCs. The clinical and in vitro English-language literature relating to the microstructure, manufacturing, strengthening, properties, surface treatments and clinical performance of LSC materials was obtained through an electronic search. Findings from relevant articles were extracted and summarised for this manuscript. There is considerable evidence supporting the mechanical and aesthetic competency of LSC variants, namely zirconia-reinforced lithium silicates and lithium–aluminium disilicates. Nonetheless, the literature assessing the biocompatibility and cytotoxicity of novel LSCs is scarce. An exploration of the chemical, mechanical and chemo-mechanical intaglio surface treatments—alternative to hydrofluoric acid etching—revealed promising adhesion performance for acid neutralisation and plasma treatment. The subtractive manufacturing methods of partially crystallised and fully crystallised LSC blocks and the additive manufacturing modalities pertaining to the fabrication of LSC dental restorations are addressed, wherein that challenges that could be encountered upon implementing novel additive manufacturing approaches using LSC print materials are highlighted. Furthermore, the short-term clinical performance of zirconia-reinforced lithium silicates and lithium–aluminium disilicates is demonstrated to be comparable to that of lithium disilicate ceramics and reveals promising potential for their long-term clinical performance. Full article
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51 pages, 5061 KiB  
Article
Films Floating on Water Surface: Coupled Redox Cycling of Iron Species (Fe(III)/Fe(II)) at Soil/Water and Water/Air Interfaces
by Hong Zhang, Zac Rush, Zoe Penn, Kami Dunn, Sydney Asmus, Carolyn Cooke, Zach Cord, Shawna Coulter and Chance Morris
Water 2024, 16(9), 1298; https://doi.org/10.3390/w16091298 (registering DOI) - 02 May 2024
Abstract
Naturally occurring Fe(III) films with rainbow reflection iridescence have been observed floating on the water surface of various spots covered with shallow water (e.g., edges of wetlands and creeks, standing water over soils). This natural phenomenon has become a scenic attraction and stimulated [...] Read more.
Naturally occurring Fe(III) films with rainbow reflection iridescence have been observed floating on the water surface of various spots covered with shallow water (e.g., edges of wetlands and creeks, standing water over soils). This natural phenomenon has become a scenic attraction and stimulated much curiosity. We pursued an experimental inquiry aimed at probing this interesting, curious natural wonder. As the first critical task, floating Fe(III) films were successfully generated in an assessable, controllable setting in our laboratory. This enabled us to establish this phenomenon reproducibly under controlled conditions and characterize the phenomenon over the entire span of the formation and transformation of the Fe(III) films. Our film generation method requires a few things: fresh soil (source for Fe(III) and microbes), glucose (energy source), and water in a container. The floating Fe(III) films as observed in the field occurred in ~1–3 day(s) on the water surface of the inundated soil mixed with the sugar. The Fe(III) films then grew from initial very thin, colorless, somewhat transparent films with rainbow reflection iridescence to colored thicker films and then to orange/orange-red/red crusts over the time. A comprehensive mechanistic picture was formulated to depict the formation of the Fe(III) films. Several sequential processes are operative. First, the Fe(III) (oxides, oxyhydroxides) in the soil is reduced to Fe(II) by the Fe(III)-reducing microbes during their anerobic respiration with Fe(III) as the electron (e) acceptor after depletion of dissolved O2 in the water as a result of aerobic microbial respiration with O2 as the e acceptor. The Fe(II), being soluble, then diffuses to the water surface where it is oxidized to Fe(III). Subsequently, the Fe(III) hydrolyzes and various Fe(III) hydrolysis products polymerize to stabilize. A polymeric model was created to account for the Fe(III) film transformation. The Fe(III) films are considered to transform from the dimers and trimers and linear polymers of Fe(OH)3 to Fe(III) polymer sheets (e.g., Fe(OH)3, FeOOH), to 3D Fe(III) polymers, and eventually to Fe2O3 colloid particles. This floating Fe(III) film phenomenon boasts an environmental chemical drama of redox cycling of Fe(III)/Fe(II) at soil/water and water/air interfaces coupled with Fe(II) transport from the inundated soil to the water surface followed by ultimate mineralization of the Fe(III) polymers. Our Fe(III) film generation method can be readily scaled up to supply Fe(III) films of rich varieties in thickness, size, morphology, and structure over the entire span of various stages of their formation and transformation as desired for various uses. This setup offers a platform needed for further controlled studies on the kinetics, mechanism, and process of abiotic and biotic nature involved in the Fe(III) film phenomenon and for exploration of versatile roles of the Fe(III) films as nanofilms in Fe(III)/Fe(II)-surface catalyzed chemical and photochemical reactions involving various natural and synthetic compounds. Full article
3 pages, 156 KiB  
Editorial
Editorial for the Special Issue Entitled “Recent Advances in Crosslinked Gels”
by Melike Firlak Demirkan and John G. Hardy
Gels 2024, 10(5), 310; https://doi.org/10.3390/gels10050310 (registering DOI) - 02 May 2024
Abstract
A gel can be defined as a semi-solid structure that has mechanical properties ranging from tough to soft, depending on their constituents [...] Full article
(This article belongs to the Special Issue Recent Advances in Crosslinked Gels)
45 pages, 2627 KiB  
Review
Changes in Sleep Duration and Sleep Timing in the General Population from before to during the First COVID-19 Lockdown: A Systematic Review and Meta-Analysis
by Chiara Ceolin, Federica Limongi, Paola Siviero, Caterina Trevisan, Marianna Noale, Filippo Catalani, Silvia Conti, Elisa Di Rosa, Elena Perdixi, Francesca Remelli, Federica Prinelli and Stefania Maggi
Int. J. Environ. Res. Public Health 2024, 21(5), 583; https://doi.org/10.3390/ijerph21050583 (registering DOI) - 02 May 2024
Abstract
Background: The COVID-19 lockdown had a profound effect on everyday life, including sleep health. This systematic review and meta-analysis evaluated changes in quantitative sleep parameters during the first lockdown compared with pre-lockdown in the general population. Methods: A search in scientific databases was [...] Read more.
Background: The COVID-19 lockdown had a profound effect on everyday life, including sleep health. This systematic review and meta-analysis evaluated changes in quantitative sleep parameters during the first lockdown compared with pre-lockdown in the general population. Methods: A search in scientific databases was performed to identify eligible observational studies from inception to 8 February 2023. We performed a random effects meta-analysis of those studies reporting (a) means of sleep duration, time in bed (TIB), and sleep timing (bedtime and wake-up time); (b) the percentages of atypical sleep duration before and during the lockdown; (c) the percentages of change in sleep duration and sleep timing. Results: A total of 154 studies were included. A small increase in sleep duration (0.25 standardized mean difference, 95% CI 0.180–0.315) was found, with 55.0% of the individuals reporting changes, predominantly an increase (35.2%). The pooled relative risk for sleeping more than 8/9 h per night was 3.31 (95% IC 2.60–4.21). There was a moderately significant delay in sleep timing and a surge in napping. Conclusion: An increase in sleep duration and napping, and delayed sleep timing were observed. High-quality studies should evaluate whether these parameters have now become chronic or have returned to pre-lockdown values. Full article
(This article belongs to the Section Global Health)
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11 pages, 475 KiB  
Article
Analysis of Macular Vascularization Using Optical Coherence Tomography Angiography in Patients with Obstructive Sleep Apnea Syndrome: A Prospective Clinical Study
by Laura Abdessater, Matthieu Hein and Florence Rasquin
Medicina 2024, 60(5), 757; https://doi.org/10.3390/medicina60050757 (registering DOI) - 02 May 2024
Abstract
Background and Objectives: Given the conflicting data available in the literature, this study aimed to investigate the impact of obstructive sleep apnea syndrome (OSAS) on the macular vascular density (VD) and perfusion density (PD). Materials and Methods: Based on the obstructive apnea–hypopnea index [...] Read more.
Background and Objectives: Given the conflicting data available in the literature, this study aimed to investigate the impact of obstructive sleep apnea syndrome (OSAS) on the macular vascular density (VD) and perfusion density (PD). Materials and Methods: Based on the obstructive apnea–hypopnea index (OAHI), 61 prospectively recruited patients were assigned to either a control group (n = 12; OAHI < 5/h) or an OSAS group (n = 49; OAHI ≥ 5/h). The macular VD and PD of the superficial and deep capillary plexuses (SCP and DCP, respectively) were measured in the parafoveolar and perifoveolar areas using Zeiss PLEX Elite 9000 (6 × 6 mm). The values were compared between the control and OSAS groups. Results: Compared with the control group, the OSAS group demonstrated an increased VD of the DCP in the parafoveolar and perifoveolar areas and PD of the DCP in the perifoveolar area. No significant differences in either the macular VD or PD of the SCP were observed. There was no correlation between the OAHI and macular VD or PD. Conclusions: This study indicates that collateral vessel formation and possible retinal vasodilation occur in the DCP of patients with OSAS. Full article
(This article belongs to the Section Ophthalmology)
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12 pages, 493 KiB  
Article
Quantum Gravity Effective Action Provides Entropy of the Universe
by Ken-ji Hamada
Particles 2024, 7(2), 465-476; https://doi.org/10.3390/particles7020026 (registering DOI) - 02 May 2024
Abstract
The effective action in the renormalizable quantum theory of gravity provides entropy because the total Hamiltonian vanishes. Since it is a renormalization group invariant that is constant in the process of cosmic evolution, we can show conservation of entropy, which is an ansatz [...] Read more.
The effective action in the renormalizable quantum theory of gravity provides entropy because the total Hamiltonian vanishes. Since it is a renormalization group invariant that is constant in the process of cosmic evolution, we can show conservation of entropy, which is an ansatz in the standard cosmology. Here, we study renormalizable quantum gravity that exhibits conformal dominance at high energy beyond the Planck scale. The current entropy of the universe is derived by calculating the effective action under the scenario of quantum gravity inflation caused by its dynamics. We then argue that ghost modes must be unphysical but are necessary for the Hamiltonian to vanish and for entropy to exist in gravitational systems. Full article
(This article belongs to the Special Issue Feature Papers for Particles 2023)
17 pages, 9249 KiB  
Article
Enhancing Yarn Quality Wavelength Spectrogram Analysis: A Semi-Supervised Anomaly Detection Approach with Convolutional Autoencoder
by Haoran Wang, Zhongze Han, Xiaoshuang Xiong, Xuewei Song and Chen Shen
Machines 2024, 12(5), 309; https://doi.org/10.3390/machines12050309 (registering DOI) - 02 May 2024
Abstract
Abnormal detection plays a pivotal role in the routine maintenance of industrial equipment. Malfunctions or breakdowns in the drafting components of spinning equipment can lead to yarn defects, thereby compromising the overall quality of the production line. Fault diagnosis of spinning equipment entails [...] Read more.
Abnormal detection plays a pivotal role in the routine maintenance of industrial equipment. Malfunctions or breakdowns in the drafting components of spinning equipment can lead to yarn defects, thereby compromising the overall quality of the production line. Fault diagnosis of spinning equipment entails the examination of component defects through Wavelet Spectrogram Analysis (WSA). Conventional detection techniques heavily rely on manual experience and lack generality. To address this limitation, this current study leverages machine learning technology to formulate a semi-supervised anomaly detection approach employing a convolutional autoencoder. This method trains deep neural networks with normal data and employs the reconstruction mode of a convolutional autoencoder in conjunction with Kernel Density Estimation (KDE) to determine the optimal threshold for anomaly detection. This facilitates the differentiation between normal and abnormal operational modes without the necessity for extensive labeled fault data. Experimental results from two sets of industrial data validate the robustness of the proposed methodology. In comparison to conventional Autoencoder and prevalent machine learning techniques, the proposed approach demonstrates superior performance across evaluation metrics such as Accuracy, Recall, Area Under the Curve (AUC), and F1-score, thereby affirming the feasibility of the suggested model. Full article
(This article belongs to the Section Machines Testing and Maintenance)
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14 pages, 3739 KiB  
Article
Exploring the Potential of Nitrogen-Doped Graphene in ZnSe-TiO2 Composite Materials for Supercapacitor Electrode
by Hassan Akbar, Asghar Ali, Shoaib Mohammad, Faiza Anjum, Ashfaq Ahmad, Amir Muhammad Afzal, Munirah D. Albaqami, Saikh Mohammad and Jeong-Ryeol Choi
Molecules 2024, 29(9), 2103; https://doi.org/10.3390/molecules29092103 (registering DOI) - 02 May 2024
Abstract
The current study explores the prospective of a nitrogen-doped graphene (NG) incorporated into ZnSe-TiO2 composites via hydrothermal method for supercapacitor electrodes. Structural, morphological, and electronic characterizations are conducted using XRD, SEM, Raman, and UV analyses. The electrochemical study is performed and galvanostatic [...] Read more.
The current study explores the prospective of a nitrogen-doped graphene (NG) incorporated into ZnSe-TiO2 composites via hydrothermal method for supercapacitor electrodes. Structural, morphological, and electronic characterizations are conducted using XRD, SEM, Raman, and UV analyses. The electrochemical study is performed and galvanostatic charge-discharge (GCD) and cyclic voltammetry (CV) are evaluated for the supercapacitor electrode material. Results demonstrate improved performance in the ZnSe-NG-TiO2 composite, indicating its potential for advanced supercapacitors with enhanced efficiency, stability, and power density. Specific capacity calculations and galvanic charge-discharge experiments confirmed the promising electrochemical activity of ZnSe-NG-TiO2, which has a specific capacity of 222 C/g. The negative link among specific capacity and current density demonstrated the composite’s potential for high energy density and high-power density electrochemical devices. Overall, the study shows that composite materials derived from multiple families can synergistically improve electrode characteristics for advanced energy storage applications. Full article
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26 pages, 5753 KiB  
Article
Upsampling Monte Carlo Reactor Simulation Tallies in Depleted Sodium-Cooled Fast Reactor Assemblies Using a Convolutional Neural Network
by Jessica Berry, Paul Romano and Andrew Osborne
Energies 2024, 17(9), 2177; https://doi.org/10.3390/en17092177 (registering DOI) - 02 May 2024
Abstract
The computational demand of neutron Monte Carlo transport simulations can increase rapidly with the spatial and energy resolution of tallied physical quantities. Convolutional neural networks have been used to increase the resolution of Monte Carlo simulations of light water reactor assemblies while preserving [...] Read more.
The computational demand of neutron Monte Carlo transport simulations can increase rapidly with the spatial and energy resolution of tallied physical quantities. Convolutional neural networks have been used to increase the resolution of Monte Carlo simulations of light water reactor assemblies while preserving accuracy with negligible additional computational cost. Here, we show that a convolutional neural network can also be used to upsample tally results from Monte Carlo simulations of sodium-cooled fast reactor assemblies, thereby extending the applicability beyond thermal systems. The convolutional neural network model is trained using neutron flux tallies from 300 procedurally generated nuclear reactor assemblies simulated using OpenMC. Validation and test datasets included 16 simulations of procedurally generated assemblies, and a realistic simulation of a European sodium-cooled fast reactor assembly was included in the test dataset. We show the residuals between the high-resolution flux tallies predicted by the neural network and high-resolution Monte Carlo tallies on relative and absolute bases. The network can upsample tallies from simulations of fast reactor assemblies with diverse and heterogeneous materials and geometries by a factor of two in each spatial and energy dimension. The network’s predictions are within the statistical uncertainty of the Monte Carlo tallies in almost all cases. This includes test assemblies for which burnup values and geometric parameters were well outside the ranges of those in assemblies used to train the network. Full article
(This article belongs to the Section B4: Nuclear Energy)
11 pages, 534 KiB  
Article
‘Successful Ageing’ Needs a Future: Older Incarcerated Adults’ Views on Ageing in Prison
by Andrea Kenkmann and Christian Ghanem
J. Ageing Longev. 2024, 4(2), 72-82; https://doi.org/10.3390/jal4020006 (registering DOI) - 02 May 2024
Abstract
Demographic changes have led to an increase in older people in prisons. Whereas the rehabilitative process of younger offenders is geared towards their reintegration into the labour market, successful ageing should be a policy aim for older prisoners. This study explores how older [...] Read more.
Demographic changes have led to an increase in older people in prisons. Whereas the rehabilitative process of younger offenders is geared towards their reintegration into the labour market, successful ageing should be a policy aim for older prisoners. This study explores how older incarcerated persons view their ageing. A qualitative study using a written survey with only the single question What does ageing in prison mean to you? was conducted in Bavaria, Germany. A total of 64 prisoners (61 male, 3 female) supplied answers varying in length from a few words to several pages. The thematic analysis revealed that together with health concerns, social relations and everyday activities, the uncertainty of the future was a central focus point for the older adults in prison. The authors propose that a positive vision of the future needs to be included in any model of successful ageing. If successful ageing is used as an aim for older prisoners, more attention needs to be paid to support interventions during and after the release process. Full article
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18 pages, 9295 KiB  
Article
Performance Evaluation of the B4 Topology for Implementing Grid-Connected Inverters in Microgrids
by Enric Torán, Marian Liberos, Iván Patrao, Raúl González-Medina, Gabriel Garcerá and Emilio Figueres
Electronics 2024, 13(9), 1755; https://doi.org/10.3390/electronics13091755 (registering DOI) - 02 May 2024
Abstract
The B4 topology is an interesting alternative to the conventional B6 inverter due to its reduced number of parts and lower cost. Although it has been widely used in the past, especially in low-power motor drive applications, its application as a grid-connected inverter [...] Read more.
The B4 topology is an interesting alternative to the conventional B6 inverter due to its reduced number of parts and lower cost. Although it has been widely used in the past, especially in low-power motor drive applications, its application as a grid-connected inverter is an open area of research. In this regard, this paper analyses the feasibility of the B4 inverter topology for grid-connected applications. A versatile 7 kW inverter prototype, which may be configured as B4 and B6, was built, allowing for a comprehensive evaluation of the performance of both topologies. Through an analytical study and experimental tests, the performance of the B4 and B6 topologies was comparatively evaluated in terms of efficiency, total harmonic distortion of line currents, current unbalance, cost, and mean time between failures. The study was carried out in the context of microgrid systems, highlighting their role in the integration of renewable energy and distributed generation. Full article
(This article belongs to the Special Issue Advancements in Power Electronics Conversion Technologies)
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17 pages, 632 KiB  
Article
A New Approach for Modeling Vertical Dynamics of Motorcycles Based on Graph Theory
by Mouad Garziad, Abdelmjid Saka, Hassane Moustabchir and Maria Luminita Scutaru
Mathematics 2024, 12(9), 1390; https://doi.org/10.3390/math12091390 (registering DOI) - 02 May 2024
Abstract
The main objective of this research is to establish a new formulation and mathematical model based on graph theory to create dynamic equations and provide clarity on the fundamental formulation. We have employed graph theory as a new approach to develop a new [...] Read more.
The main objective of this research is to establish a new formulation and mathematical model based on graph theory to create dynamic equations and provide clarity on the fundamental formulation. We have employed graph theory as a new approach to develop a new representation and formulate the vertical dynamics of a motorcycle with four degrees of freedom, including a suspension and tire model. We have outlined the principal procedural steps required to generate the mathematical and dynamic equations. This systematic approach ensures clarity and precision in our formulation process and representation. Subsequently, we implemented the dynamics equations to examine the dynamic behavior of both the sprung and unsprung masses’ vertical displacements, while considering the varying conditions of the road profile. Full article
(This article belongs to the Section Engineering Mathematics)
8 pages, 491 KiB  
Review
Uncovering the Role of the Early Visual Cortex in Visual Mental Imagery
by Nadine Dijkstra
Vision 2024, 8(2), 29; https://doi.org/10.3390/vision8020029 (registering DOI) - 02 May 2024
Abstract
The question of whether the early visual cortex (EVC) is involved in visual mental imagery remains a topic of debate. In this paper, I propose that the inconsistency in findings can be explained by the unique challenges associated with investigating EVC activity during [...] Read more.
The question of whether the early visual cortex (EVC) is involved in visual mental imagery remains a topic of debate. In this paper, I propose that the inconsistency in findings can be explained by the unique challenges associated with investigating EVC activity during imagery. During perception, the EVC processes low-level features, which means that activity is highly sensitive to variation in visual details. If the EVC has the same role during visual mental imagery, any change in the visual details of the mental image would lead to corresponding changes in EVC activity. Within this context, the question should not be whether the EVC is ‘active’ during imagery but how its activity relates to specific imagery properties. Studies using methods that are sensitive to variation in low-level features reveal that imagery can recruit the EVC in similar ways as perception. However, not all mental images contain a high level of visual details. Therefore, I end by considering a more nuanced view, which states that imagery can recruit the EVC, but that does not mean that it always does so. Full article
(This article belongs to the Special Issue Visual Mental Imagery System: How We Image the World)
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27 pages, 2276 KiB  
Review
Sentiment Dimensions and Intentions in Scientific Analysis: Multilevel Classification in Text and Citations
by Kampatzis Aristotelis, Sidiropoulos Antonis, Diamantaras Konstantinos and Ougiaroglou Stefanos
Electronics 2024, 13(9), 1753; https://doi.org/10.3390/electronics13091753 (registering DOI) - 02 May 2024
Abstract
Sentiment Analysis in text, especially text containing scientific citations, is an emerging research field with important applications in the research community. This review explores the field of sentiment analysis by focusing on the interpretation of citations, presenting a detailed description of techniques and [...] Read more.
Sentiment Analysis in text, especially text containing scientific citations, is an emerging research field with important applications in the research community. This review explores the field of sentiment analysis by focusing on the interpretation of citations, presenting a detailed description of techniques and methods ranging from lexicon-based approaches to Machine and Deep Learning models. The importance of understanding both the emotion and the intention behind citations is emphasized, reflecting their critical role in scientific communication. In addition, this study presents the challenges faced by researchers (such as complex scientific terminology, multilingualism, and the abstract nature of scientific discourse), highlighting the need for specialized language processing techniques. Finally, future research directions include improving the quality of datasets as well as exploring architectures and models to improve the accuracy of sentiment detection. Full article
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14 pages, 939 KiB  
Article
Feasibility and Acceptability of a Meditation Mobile App Intervention for Adolescent and Young Adult Survivors of Childhood Cancer
by Gary Kwok, Archana Sharma, Ivelisse Mandato and Katie A. Devine
Int. J. Environ. Res. Public Health 2024, 21(5), 584; https://doi.org/10.3390/ijerph21050584 (registering DOI) - 02 May 2024
Abstract
Background: Adolescent and young adult (AYA) survivors of childhood cancer are increasingly recognized as a vulnerable group with unique emotional, social, and practical needs due to the intersection of cancer survivorship and normal developmental processes. Mindfulness meditation has shown early efficacy in improving [...] Read more.
Background: Adolescent and young adult (AYA) survivors of childhood cancer are increasingly recognized as a vulnerable group with unique emotional, social, and practical needs due to the intersection of cancer survivorship and normal developmental processes. Mindfulness meditation has shown early efficacy in improving psychological distress among cancer patients. However, the overall scientific study of app-based mindfulness-based interventions is still in its early stages. The goal of this study was to evaluate the feasibility and acceptability of a commercially available mindfulness mobile app intervention “Ten Percent Happier” among AYA survivors of childhood cancer. Methods: We conducted a single-arm pilot intervention with 25 AYA survivors of childhood cancer ages 18–29 years. Results: A total of 108 potentially eligible individuals were initially identified for screening. Of the 45 individuals reached (contact rate = 41.67%), 20 declined to participate; 25 were enrolled in the study and completed the baseline survey (enrollment rate = 55.56%). Twenty-one participants completed the study (retention rate = 84%). Changes in several outcomes were promising, with medium to large effect sizes: Mindfulness (d = 0.74), Negative Emotion (d = 0.48), Perceived Stress (d = 0.52), and Mental Health (d = 0.45). Furthermore, results suggested that participants with consistent app usage showed greater improvement in reported outcomes than those who stopped their usage (e.g., Mindfulness: d = 0.74, Perceived Stress: d = 0.83, Mental Health: d = 0.51; Meaning and Purpose: d = 0.84; and Sleep Disturbance: d = 0.81). Qualitative feedback indicated high satisfaction, but participants suggested adding group or individual peer support to improve their experience with the app. Conclusions: AYA survivors can be difficult to reach, but a mindfulness app was feasible and acceptable to this group. In particular, the robust retention rate and high satisfaction ratings indicate that the meditation mobile app was well received. Preliminary results suggest positive changes in health-related quality of life outcomes, warranting a larger efficacy trial. Full article
(This article belongs to the Special Issue Mental Health of Cancer Patients and Caregivers)
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18 pages, 500 KiB  
Article
Appraising the Physical Activity Levels of Saudis with Physical Disabilities: Effects of Disability Type, Mobility Assistive Devices, and Demographic Factors
by Mohamed A. Said and Majed M. Alhumaid
Healthcare 2024, 12(9), 937; https://doi.org/10.3390/healthcare12090937 (registering DOI) - 02 May 2024
Abstract
Physical activity (PA) has numerous health benefits for individuals with physical disabilities (IWPD). However, it is common for activity levels to fall below the suggested limits. This study aimed to evaluate the prevalence, pattern, and levels of PA among IWPD in Saudi Arabia. [...] Read more.
Physical activity (PA) has numerous health benefits for individuals with physical disabilities (IWPD). However, it is common for activity levels to fall below the suggested limits. This study aimed to evaluate the prevalence, pattern, and levels of PA among IWPD in Saudi Arabia. It also investigated the effects of individuals’ type of disability, mobility assistive devices, and demographic features on PA levels. Data were collected from 238 participants, mostly male (62.2%), aged 39.76 ± 12.19 years. Among them, 19.3% had spinal conditions, 14.7% had progressive muscular dystrophy, 15.1% had multiple sclerosis, 17.6% had cerebral palsy, 16.4% had poliomyelitis, and 16.8% had limb or foot amputations. The participants were assessed using the Arabic version of the Physical Activity Scale for Individuals with Physical Disabilities (PASIPD-AR). The results showed that 62.6% (64.9% of males and 58.9% of females) met the minimum PA guidelines specified by the WHO. The average PASIPD-AR score was 10.33 ± 10.67 MET-hours/day, indicating lower PA levels, and 8.4% of individuals did not participate in any form of PA. Significant discrepancies were detected in disability type and mobility assistive device use after age adjustment. Marital status, education, and occupation greatly affected PA components. Greater attention should be paid to promoting an active lifestyle among IWPD in Saudi Arabia. Full article
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13 pages, 2667 KiB  
Article
Rosarugosides A and D from Rosa rugosa Flower Buds: Their Potential Anti-Skin-Aging Effects in TNF-α-Induced Human Dermal Fibroblasts
by Kang Sub Kim, So-Ri Son, Yea Jung Choi, Yejin Kim, Si-Young Ahn, Dae Sik Jang and Sullim Lee
Plants 2024, 13(9), 1266; https://doi.org/10.3390/plants13091266 (registering DOI) - 02 May 2024
Abstract
This present study investigated the anti-skin-aging properties of Rosa rugosa. Initially, phenolic compounds were isolated from a hot water extract of Rosa rugosa’s flower buds. Through repeated chromatography (column chromatography, MPLC, and prep HPLC), we identified nine phenolic compounds (1 [...] Read more.
This present study investigated the anti-skin-aging properties of Rosa rugosa. Initially, phenolic compounds were isolated from a hot water extract of Rosa rugosa’s flower buds. Through repeated chromatography (column chromatography, MPLC, and prep HPLC), we identified nine phenolic compounds (19), including a previously undescribed depside, rosarugoside D (1). The chemical structure of 1 was elucidated via NMR, HR-MS, UV, and hydrolysis. Next, in order to identify bioactive compounds that are effective against TNF-α-induced NHDF cells, we measured intracellular ROS production in samples treated with each of the isolated compounds (19). All isolates reduced the level of ROS at a concentration of 10 μM. Particularly, two depsides—rosarugosides A and D (2 and 1)—significantly inhibited ROS expression in TNF-α-induced NHDFs compared to the other phenolic compounds. Subsequently, the production of MMP-1 and procollagen type Ι α1 by these two depsides was examined. Remarkably, rosarugoside A (2) significantly decreased MMP-1 secretion at all concentrations. In contrast, rosarugoside D (1) regulated the expression of procollagen type Ι α1. These findings collectively suggest that Rosa rugosa extracts and their isolated compounds, rosarugosides A (2) and D (1), hold significant potential for protecting against aging and skin damage. Overall, these findings suggest that Rosa rugosa extracts and their isolated compounds, rosarugosides A (2) and D (1), have the potential to prevent and protect against aging and skin damage, although more specific quantitative analysis is needed. Full article
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13 pages, 726 KiB  
Review
A Comparative Analysis of Mechanical Properties of Polyetheretherketone (PEEK) vs. Standard Materials Used in Orthodontic Fixed Appliances: A Systematic Review
by Pyi-Phyo Win, Oak Gar Moe, De-Shing Chen, Tzu-Yu Peng and Hsin-Chung Cheng
Polymers 2024, 16(9), 1271; https://doi.org/10.3390/polym16091271 (registering DOI) - 02 May 2024
Abstract
Polyetheretherketone (PEEK), an organic thermoplastic polymer, has gained interest in dentistry due to its excellent mechanical strength, flexibility, and biocompatibility. Furthermore, the ability to utilize CAD/CAM in the fabrication of PEEK enhances accuracy, reliability, and efficiency while also saving time. Hence, several orthodontic [...] Read more.
Polyetheretherketone (PEEK), an organic thermoplastic polymer, has gained interest in dentistry due to its excellent mechanical strength, flexibility, and biocompatibility. Furthermore, the ability to utilize CAD/CAM in the fabrication of PEEK enhances accuracy, reliability, and efficiency while also saving time. Hence, several orthodontic studies have explored the utilization of PEEK in various applications, such as archwires, brackets, fixed lingual retainers, palatal expansion devices, transpalatal arches, Tübingen palatal plates, different types of space maintainers, mini-implant insertion guides, and more. However, a complete systematic review of the available data comparing the performance of PEEK with traditional orthodontic materials has not yet been conducted. Therefore, this systematic review seeks to assess if PEEK material meets the required mechanical criteria to serve as an alternative to conventional orthodontic appliances. To ensure clarity and precision, this review will specifically concentrate on fixed appliances. This systemic review followed the PRISMA guidelines and utilized databases including PubMed/MEDLINE, Embase, Springer, Web of Science, and Wiley. Searches were restricted to English language articles from January 2013 to February 2024. Keywords such as “Polyetheretherketone” or “PEEK” and “Orthodontic” or “Orthodontic device” or “Orthodontic materials” were employed across all databases. Nine studies were incorporated, covering orthodontic archwires, brackets, and fixed lingual retainers. Based on the reviewed literature, PEEK demonstrates promising potential in orthodontic fixed appliances, offering advantages in force delivery, friction reduction, and aesthetic appeal. Further research is needed to fully explore its capabilities and optimize its application in clinical practice. Full article
(This article belongs to the Special Issue Biocompatible and Biodegradable Polymers for Medical Applications II)
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