The 2023 MDPI Annual Report has
been released!
 
18 pages, 5386 KiB  
Article
Quasi/Periodic Noise Reduction in Images Using Modified Multiresolution-Convolutional Neural Networks for 3D Object Reconstructions and Comparison with Other Convolutional Neural Network Models
by Osmar Antonio Espinosa-Bernal, Jesús Carlos Pedraza-Ortega, Marco Antonio Aceves-Fernandez, Victor Manuel Martínez-Suárez, Saul Tovar-Arriaga, Juan Manuel Ramos-Arreguín and Efrén Gorrostieta-Hurtado
Computers 2024, 13(6), 145; https://doi.org/10.3390/computers13060145 (registering DOI) - 7 Jun 2024
Abstract
The modeling of real objects digitally is an area that has generated a high demand due to the need to obtain systems that are able to reproduce 3D objects from real objects. To this end, several techniques have been proposed to model objects [...] Read more.
The modeling of real objects digitally is an area that has generated a high demand due to the need to obtain systems that are able to reproduce 3D objects from real objects. To this end, several techniques have been proposed to model objects in a computer, with the fringe profilometry technique being the one that has been most researched. However, this technique has the disadvantage of generating Moire noise that ends up affecting the accuracy of the final 3D reconstructed object. In order to try to obtain 3D objects as close as possible to the original object, different techniques have been developed to attenuate the quasi/periodic noise, namely the application of convolutional neural networks (CNNs), a method that has been recently applied for restoration and reduction and/or elimination of noise in images applied as a pre-processing in the generation of 3D objects. For this purpose, this work is carried out to attenuate the quasi/periodic noise in images acquired by the fringe profilometry technique, using a modified CNN-Multiresolution network. The results obtained are compared with the original CNN-Multiresolution network, the UNet network, and the FCN32s network and a quantitative comparison is made using the Image Mean Square Error E (IMMS), Peak Signal-to-Noise Ratio (PSNR), Structural Similarity Index (SSIM), and Profile (MSE) metrics. Full article
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10 pages, 242 KiB  
Perspective
Post-traumatic Stress Disorder in Veterans: A Concept Analysis
by Tormechi Chambliss, Jung-Lung Hsu and Mei-Lan Chen
Behav. Sci. 2024, 14(6), 485; https://doi.org/10.3390/bs14060485 (registering DOI) - 7 Jun 2024
Abstract
Post-traumatic stress disorder (PTSD) occurs when an individual experiences a traumatic event that exceeds the limits of psychological endurance. Many veterans experience PTSD. PTSD can negatively impact veterans’ quality of life, functioning, life satisfaction, and overall well-being. It is important to analyze the [...] Read more.
Post-traumatic stress disorder (PTSD) occurs when an individual experiences a traumatic event that exceeds the limits of psychological endurance. Many veterans experience PTSD. PTSD can negatively impact veterans’ quality of life, functioning, life satisfaction, and overall well-being. It is important to analyze the concept of PTSD in the veteran population. This concept analysis aimed to investigate the defining attributes, a model case, antecedents, consequences, and empirical referents related to the concept of PTSD among veterans. Walker and Avant’s method was used to guide this concept analysis of PTSD. The results showed that three attributes were determined from the analysis: intrusive memories of traumatic events, feelings of isolation and estrangement, and negative cognitions. PTSD is conceptualized as a collection of symptoms that arise from highly traumatic experiences. The military environment predisposes veterans to traumatic events that should be identified or acknowledged. A better understanding of the concept of PTSD can facilitate the development of effective interventions for the veteran population and enhance their mental health. Full article
(This article belongs to the Section Psychiatric, Emotional and Behavioral Disorders)
18 pages, 3341 KiB  
Article
Phaseolus coccineus L. Landraces in Greece: Microsatellite Genotyping and Molecular Characterization for Landrace Authenticity and Discrimination
by Irene Bosmali, Georgios Lagiotis, Ioannis Ganopoulos, Eleni Stefanidou, Panagiotis Madesis and Costas G. Biliaderis
BioTech 2024, 13(2), 18; https://doi.org/10.3390/biotech13020018 (registering DOI) - 7 Jun 2024
Abstract
Phaseolus coccineus L. is a highly valuable crop for human consumption with a high protein content and other associated health benefits. Herein, 14 P. coccineus L. landraces were selected for genetic characterization: two Protected Geographical Indication (PGI) landraces from the Prespon area, namely [...] Read more.
Phaseolus coccineus L. is a highly valuable crop for human consumption with a high protein content and other associated health benefits. Herein, 14 P. coccineus L. landraces were selected for genetic characterization: two Protected Geographical Indication (PGI) landraces from the Prespon area, namely “Gigantes” (“G”) and “Elephantes” (“E”), and 12 additional landraces from the Greek Gene Bank collection of beans (PC1–PC12). The genetic diversity among these landraces was assessed using capillary electrophoresis utilizing fluorescence-labeled Simple Sequence Repeat (SSR) and Expressed Sequence Tag (EST); Simple Sequence Repeat (SSR) is a molecular marker technology. The “G” and “E” Prespon landraces were clearly distinguished among them, as well as from the PC1 to PC12 landraces, indicating the unique genetic identity of the Prespon beans. Overall, the genetic characterization of the abundant Greek bean germplasm using molecular markers can aid in the genetic identification of “G” and “E” Prespon beans, thus preventing any form of fraudulent practices as well as supporting traceability management strategies for the identification of authenticity, and protection of the origin of local certified products. Full article
(This article belongs to the Section Agricultural and Food Biotechnology)
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16 pages, 1990 KiB  
Article
Rats Lacking the Dopamine Transporter Display Inflexibility in Innate and Learned Behavior
by Anastasia Belskaya, Natalia Kurzina, Artem Savchenko, Ilya Sukhanov, Arina Gromova, Raul R. Gainetdinov and Anna Volnova
Biomedicines 2024, 12(6), 1270; https://doi.org/10.3390/biomedicines12061270 (registering DOI) - 7 Jun 2024
Abstract
Playing a key role in the organization of striatal motor output, the dopamine (DA)-ergic system regulates both innate and complex learned behaviors. Growing evidence clearly indicates the involvement of the DA-ergic system in different forms of repetitive (perseverative) behavior. Some of these behaviors [...] Read more.
Playing a key role in the organization of striatal motor output, the dopamine (DA)-ergic system regulates both innate and complex learned behaviors. Growing evidence clearly indicates the involvement of the DA-ergic system in different forms of repetitive (perseverative) behavior. Some of these behaviors accompany such disorders as obsessive–compulsive disorder (OCD), Tourette’s syndrome, schizophrenia, and addiction. In this study, we have traced how the inflexibility of repetitive reactions in the recently developed animal model of hyper-DA-ergia, dopamine transporter knockout rats (DAT-KO rats), affects the realization of innate behavior (grooming) and the learning of spatial (learning and reversal learning in T-maze) and non-spatial (extinction of operant reaction) tasks. We found that the microstructure of grooming in DAT-KO rats significantly differed in comparison to control rats. DAT-KO rats more often demonstrated a fixed syntactic chain, making fewer errors and very rarely missing the chain steps in comparison to control rats. DAT-KO rats’ behavior during inter-grooming intervals was completely different to the control animals. During learning and reversal learning in the T-maze, DAT-KO rats displayed pronounced patterns of hyperactivity and perseverative (stereotypical) activity, which led to worse learning and a worse performance of the task. Most of the DAT-KO rats could not properly learn the behavioral task in question. During re-learning, DAT-KO rats demonstrated rigid perseverative activity even in the absence of any reinforcement. In operant tasks, the mutant rats demonstrated poor extinction of operant lever pressing: they continued to perform lever presses despite no there being reinforcement. Our results suggest that abnormally elevated DA levels may be responsible for behavioral rigidity. It is conceivable that this phenomenon in DAT-KO rats reflects some of the behavioral traits observed in clinical conditions associated with endogenous or exogenous hyper-DA-ergia, such as schizophrenia, substance abuse, OCD, patients with Parkinson disease treated with DA mimetics, etc. Thus, DAT-KO rats may be a valuable behavioral model in the search for new pharmacological approaches to treat such illnesses. Full article
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3 pages, 168 KiB  
Editorial
Immune Checkpoint Inhibitors in Non-Small Cell Lung Cancer (NSCLC) Treatment: Quo Vadis?
by Antonios N. Gargalionis, Kostas A. Papavassiliou and Athanasios G. Papavassiliou
Int. J. Mol. Sci. 2024, 25(12), 6309; https://doi.org/10.3390/ijms25126309 (registering DOI) - 7 Jun 2024
Abstract
Lung cancer has been established as the second most common cancer worldwide (most common cancer in men and second most common cancer in women) and as the leading cause of cancer morbidity among neoplasms [...] Full article
27 pages, 12339 KiB  
Review
Potential of Carbon Aerogels in Energy: Design, Characteristics, and Applications
by Gazi A. K. M. Rafiqul Bari and Jae-Ho Jeong
Gels 2024, 10(6), 389; https://doi.org/10.3390/gels10060389 (registering DOI) - 7 Jun 2024
Abstract
In energy applications, the use of materials with hierarchical porous structures and large surface areas is essential for efficient charge storage. These structures facilitate rapid electron and ion transport, resulting in high power density and quick charge/discharge capabilities. Carbon-based materials are extensively utilized [...] Read more.
In energy applications, the use of materials with hierarchical porous structures and large surface areas is essential for efficient charge storage. These structures facilitate rapid electron and ion transport, resulting in high power density and quick charge/discharge capabilities. Carbon-based materials are extensively utilized due to their tunable properties, including pore sizes ranging from ultra- to macropores and surface polarity. Incorporating heteroatoms such as nitrogen, oxygen, sulfur, phosphorus, and boron modifies the carbon structure, enhancing electrocatalytic properties and overall performance. A hierarchical pore structure is necessary for optimal performance, as it ensures efficient access to the material’s core. The microstructure of carbon materials significantly impacts energy storage, with factors like polyaromatic condensation, crystallite structure, and interlayer distance playing crucial roles. Carbon aerogels, derived from the carbonization of organic gels, feature a sponge-like structure with large surface area and high porosity, making them suitable for energy storage. Their open pore structure supports fast ion transfer, leading to high energy and power densities. Challenges include maintaining mechanical or structural integrity, multifunctional features, and scalability. This review provides an overview of the current progress in carbon-based aerogels for energy applications, discussing their properties, development strategies, and limitations, and offering significant guidance for future research requirements. Full article
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20 pages, 5306 KiB  
Article
Conservative Evaluation of Fault Displacement Hazard for a Nuclear Site in Case of Insufficient Data on the Fault Activity
by Tamás János Katona
Geosciences 2024, 14(6), 158; https://doi.org/10.3390/geosciences14060158 (registering DOI) - 7 Jun 2024
Abstract
The safety regulations require periodic reviews of the site hazards when operating nuclear power plants. If any indications of Quaternary fault activity are revealed, the fault displacement hazard should be evaluated. Signs of paleo-liquefaction were recently found at the nuclear site of Paks, [...] Read more.
The safety regulations require periodic reviews of the site hazards when operating nuclear power plants. If any indications of Quaternary fault activity are revealed, the fault displacement hazard should be evaluated. Signs of paleo-liquefaction were recently found at the nuclear site of Paks, Hungary, indicating the late-Pleistocene activity of the fault crossing the site. Except for this, there are no historical or instrumental records of earthquakes at the fault, and the micro-seismic and GPS monitoring results do not indicate activity either. Despite a thorough site investigation of over 40 years, the indications are uncertain and insufficient for defining the fault activity, as required for a probabilistic fault displacement hazard analysis. This paper develops and applies a simplified conservative hazard evaluation method of average fault displacement that allows an in-time decision regarding the safety relevance of the hazard. Geometrical simplification is possible since the fault crosses the site. The fault’s activity is evaluated using magnitude–frequency relations of the area sources developed for probabilistic seismic hazard analysis. The total probability theorem is applied, and different strike-slip fault scaling relations are considered while calculating the probability of non-zero surface displacement, fault rupture length, and average displacement. The fault displacement hazard curve is defined and compared with earlier studies for the same site. Since the late recognition of active faults cannot be excluded at several operating plant sites, the methodology can be applied in the future beyond a single application for the Paks site in Hungary. Full article
(This article belongs to the Special Issue New Trends in Earthquake Engineering and Seismotectonics)
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16 pages, 3068 KiB  
Review
Fibroblast Yap/Taz Signaling in Extracellular Matrix Homeostasis and Tissue Fibrosis
by Cong-Qiu Chu and Taihao Quan
J. Clin. Med. 2024, 13(12), 3358; https://doi.org/10.3390/jcm13123358 (registering DOI) - 7 Jun 2024
Abstract
Tissue fibrosis represents a complex pathological condition characterized by the excessive accumulation of collagenous extracellular matrix (ECM) components, resulting in impaired organ function. Fibroblasts are central to the fibrotic process and crucially involved in producing and depositing collagen-rich ECM. Apart from their primary [...] Read more.
Tissue fibrosis represents a complex pathological condition characterized by the excessive accumulation of collagenous extracellular matrix (ECM) components, resulting in impaired organ function. Fibroblasts are central to the fibrotic process and crucially involved in producing and depositing collagen-rich ECM. Apart from their primary function in ECM synthesis, fibroblasts engage in diverse activities such as inflammation and shaping the tissue microenvironment, which significantly influence cellular and tissue functions. This review explores the role of Yes-associated protein (Yap) and Transcriptional co-activator with PDZ-binding motif (Taz) in fibroblast signaling and their impact on tissue fibrosis. Gaining a comprehensive understanding of the intricate molecular mechanisms of Yap/Taz signaling in fibroblasts may reveal novel therapeutic targets for fibrotic diseases. Full article
(This article belongs to the Special Issue Tissue Scarring, Fibrosis and Regeneration)
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11 pages, 1187 KiB  
Article
Mercury Dynamics in the Sea of Azov: Insights from a Mass Balance Model
by Christoph Gade, Rebecca von Hellfeld, Lenka Mbadugha and Graeme Paton
Toxics 2024, 12(6), 417; https://doi.org/10.3390/toxics12060417 (registering DOI) - 7 Jun 2024
Abstract
The Sea of Azov, an inland shelf sea bounding Ukraine and Russia, experiences the effects of ongoing and legacy pollution. One of the main contaminants of concern is the heavy metal mercury (Hg), which is emitted from the regional coal industry, former Hg [...] Read more.
The Sea of Azov, an inland shelf sea bounding Ukraine and Russia, experiences the effects of ongoing and legacy pollution. One of the main contaminants of concern is the heavy metal mercury (Hg), which is emitted from the regional coal industry, former Hg refineries, and the historic use of mercury-containing pesticides. The aquatic biome acts both as a major sink and source in this cycle, thus meriting an examination of its environmental fate. This study collated existing Hg data for the SoA and the adjacent region to estimate current Hg influxes and cycling in the ecosystem. The mercury-specific model “Hg Environmental Ratios Multimedia Ecosystem Sources” (HERMES), originally developed for Canadian freshwater lakes, was used to estimate anthropogenic emissions to the sea and regional atmospheric Hg concentrations. The computed water and sediment concentrations (6.8 ng/L and 55.7 ng/g dw, respectively) approximate the reported literature values. The ongoing military conflict will increase environmental pollution in the region, thus further intensifying the existing (legacy) anthropogenic pressures. The results of this study provide a first insight into the environmental Hg cycle of the Sea of Azov ecosystem and underline the need for further emission control and remediation efforts to safeguard environmental quality. Full article
(This article belongs to the Special Issue Monitoring and Assessment of Mercury Pollution)
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10 pages, 496 KiB  
Article
Associations of Physical Fitness with Cognitive Performance in Children Aged 7–12 Years: A Cross-Sectional Study
by Rafael Cortés-Rojas, María Isabel Castellano-Ruiz, Alberto Baeza-Medina, Francisco Javier Gil-Espinosa, Francisco Álvarez-Salvago and José Daniel Jiménez-García
Appl. Sci. 2024, 14(12), 4965; https://doi.org/10.3390/app14124965 (registering DOI) - 7 Jun 2024
Abstract
(1) Background: The objective of the present study was to analyze the association of physical fitness, specifically lower limb strength, abdominal strength, vertical jump, and grip strength, with cognitive performance, specifically focusing on selective attention and memory in children aged 7 to 12 [...] Read more.
(1) Background: The objective of the present study was to analyze the association of physical fitness, specifically lower limb strength, abdominal strength, vertical jump, and grip strength, with cognitive performance, specifically focusing on selective attention and memory in children aged 7 to 12 years. (2) Methods: Two hundred twenty-seven students participated in this study. Pearson correlation was used to analyze potential relationships between the independent variables and dependent variables. (3) Results: In relation to physical fitness, a higher number of abdominal repetitions performed in 30 s showed a significant and positive association with a higher number of correct responses assessed by the Stroop Test. Furthermore, at a functional level, higher grip strength correlated with a greater number of correct responses and a higher average correct response time in the Stroop Test. Additionally, grip strength showed a significant and positive correlation with the number of words recalled assessed by the word recall test. Our key findings showed a significant association of grip strength with the categories of cognitive status, selective attention, and memory. (4) Conclusions: This study reveals that physical fitness levels, especially grip strength and abdominal strength, correlate with selective attention capacity in primary school students. Full article
(This article belongs to the Special Issue Exercise, Fitness, Human Performance and Health)
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20 pages, 2445 KiB  
Article
Heterogenous Induction of Blocking Antibodies against Ragweed Allergen Molecules by Allergen Extract-Based Immunotherapy Vaccines
by Lauriana-Eunice Zbîrcea, Maria-Roxana Buzan, Manuela Grijincu, Monica-Daniela Cotarcă, Tudor-Paul Tamaș, Laura Haidar, Gabriela Tănasie, Ioan Huțu, Elijahu Babaev, Frank Stolz, Rudolf Valenta, Virgil Păunescu, Carmen Panaitescu and Kuan-Wei Chen
Vaccines 2024, 12(6), 635; https://doi.org/10.3390/vaccines12060635 (registering DOI) - 7 Jun 2024
Abstract
Currently, allergen-specific immunotherapy (AIT) for ragweed allergy is still based on natural allergen extracts. This study aimed to analyse the ability of four commercially available AIT vaccines (CLUSTOID, TYRO-SIT, POLLINEX Quattro Plus and Diater Depot) regarding their ability to induce IgG antibodies against [...] Read more.
Currently, allergen-specific immunotherapy (AIT) for ragweed allergy is still based on natural allergen extracts. This study aimed to analyse the ability of four commercially available AIT vaccines (CLUSTOID, TYRO-SIT, POLLINEX Quattro Plus and Diater Depot) regarding their ability to induce IgG antibodies against ragweed pollen allergens in rabbits. Accordingly, the IgG reactivity of AIT-induced rabbit sera was tested for ten different ragweed pollen allergens (Amb a 1, 3, 4, 5, 6, 8, 9, 10, 11 and 12) by an ELISA. Furthermore, the ability of rabbit AIT-specific sera to block allergic patients’ IgE binding to relevant ragweed allergens (Amb a 1, 4, 6, 8 and 11) and to inhibit allergen-induced basophil activation was evaluated by an IgE inhibition ELISA and a mediator release assay. Only two AIT vaccines (Diater Depot > CLUSTOID) induced relevant IgG antibody levels to the major ragweed allergen Amb a 1. The IgG responses induced by the AIT vaccines against the other ragweed allergens were low and highly heterogeneous. Interestingly, the kinetics of IgG responses were different among the AIT vaccines and even within one AIT vaccine (Diater Depot) for Amb a 1 (long-lasting) versus Amb a 8 and Amb a 11 (short-lived). This could be due to variations in allergen contents, the immunogenicity of the allergens, and different immunization protocols. The IgE inhibition experiments showed that rabbit AIT-specific sera containing high allergen-specific IgG levels were able to inhibit patients’ IgE binding and prevent the mediator release with Diater Depot. The high levels of allergen-specific IgG levels were associated with their ability to prevent the recognition of allergens by patients’ IgE and allergen-induced basophil activation, indicating that the measurement of allergen-induced IgG could be a useful surrogate marker for the immunological efficacy of vaccines. Accordingly, the results of our study may be helpful for the selection of personalized AIT vaccination strategies for ragweed-allergic patients. Full article
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22 pages, 1957 KiB  
Article
Optimising Combat Readiness: Practical Strategies for Integrating Physiological and Psychological Resilience in Soldier Training
by José Francisco Tornero-Aguilera, Maria Stergiou, Alejandro Rubio-Zarapuz, Alexandra Martín-Rodríguez, Luís Miguel Massuça and Vicente Javier Clemente-Suárez
Healthcare 2024, 12(12), 1160; https://doi.org/10.3390/healthcare12121160 (registering DOI) - 7 Jun 2024
Abstract
This narrative review examines the intricate psychophysiological interplay between cognitive functions and physical responses within military personnel engaged in combat. It elucidates the spectrum of responses elicited by symmetric and asymmetric warfare alongside specialised combat scenarios, including close-quarters and subterranean warfare. Central to [...] Read more.
This narrative review examines the intricate psychophysiological interplay between cognitive functions and physical responses within military personnel engaged in combat. It elucidates the spectrum of responses elicited by symmetric and asymmetric warfare alongside specialised combat scenarios, including close-quarters and subterranean warfare. Central to this discourse is the emphasis on integrating training programs beyond physical conditioning to encompass psychological resilience and decision-making efficacy under duress. The exploration further ventures into applying advanced technologies such as virtual reality and wearable devices, highlighting their pivotal role in augmenting training outcomes and supporting soldier health. Through a detailed analysis of psychophysiological variations across different military branches of service, the narrative review advocates for bespoke training regimens and support frameworks tailored to address the unique exigencies of each service branch. Concluding observations stress the importance of evolving military training paradigms, advocating for adopting realistic, immersive training simulations that mirror the complexities of the contemporary battlefield. This synthesis aims to contribute to the ongoing discourse on optimising military training protocols and enhancing the operational readiness and well-being of armed forces personnel. This narrative review is essential for military psychologists, trainers, and policymakers, aiming to bridge the gap between theoretical knowledge and practical implementation in military training programs. Full article
(This article belongs to the Special Issue Health and Readiness of Tactical Populations)
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18 pages, 1546 KiB  
Article
Gene Expression Analysis of Yeast Strains with a Nonsense Mutation in the eRF3-Coding Gene Highlights Possible Mechanisms of Adaptation
by Evgeniia M. Maksiutenko, Yury A. Barbitoff, Lavrentii G. Danilov, Andrew G. Matveenko, Olga M. Zemlyanko, Elena P. Efremova, Svetlana E. Moskalenko and Galina A. Zhouravleva
Int. J. Mol. Sci. 2024, 25(12), 6308; https://doi.org/10.3390/ijms25126308 (registering DOI) - 7 Jun 2024
Abstract
In yeast Saccharomyces cerevisiae, there are two translation termination factors, eRF1 (Sup45) and eRF3 (Sup35), which are essential for viability. Previous studies have revealed that presence of nonsense mutations in these genes leads to amplification of mutant alleles (sup35-n and sup45-n [...] Read more.
In yeast Saccharomyces cerevisiae, there are two translation termination factors, eRF1 (Sup45) and eRF3 (Sup35), which are essential for viability. Previous studies have revealed that presence of nonsense mutations in these genes leads to amplification of mutant alleles (sup35-n and sup45-n), which appears to be necessary for the viability of such cells. However, the mechanism of this phenomenon remained unclear. In this study, we used RNA-Seq and proteome analysis to reveal the complete set of gene expression changes that occur during cellular adaptation to the introduction of the sup35-218 nonsense allele. Our analysis demonstrated significant changes in the transcription of genes that control the cell cycle: decreases in the expression of genes of the anaphase promoting complex APC/C (APC9, CDC23) and their activator CDC20, and increases in the expression of the transcription factor FKH1, the main cell cycle kinase CDC28, and cyclins that induce DNA biosynthesis. We propose a model according to which yeast adaptation to nonsense mutations in the translation termination factor genes occurs as a result of a delayed cell cycle progression beyond the G2-M stage, which leads to an extension of the S and G2 phases and an increase in the number of copies of the mutant sup35-n allele. Full article
(This article belongs to the Special Issue Yeast: Molecular and Cell Biology 2.0)
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11 pages, 2465 KiB  
Article
Behind the Door: Practical Parameterization of Propagation Parameters for IEEE 802.11ad Use Cases
by Luciano Ahumada, Erick Carreño, Albert Anglès, Diego Dujovne and Pablo Palacios Játiva
Technologies 2024, 12(6), 85; https://doi.org/10.3390/technologies12060085 (registering DOI) - 7 Jun 2024
Abstract
The integration of the 60 GHz band into the IEEE 802.11 standard has revolutionized indoor wireless services. However, this band presents unique challenges to indoor wireless communication infrastructure, originally designed to handle data traffic in residential and office environments. Estimating 60 GHz signal [...] Read more.
The integration of the 60 GHz band into the IEEE 802.11 standard has revolutionized indoor wireless services. However, this band presents unique challenges to indoor wireless communication infrastructure, originally designed to handle data traffic in residential and office environments. Estimating 60 GHz signal propagation in indoor settings is particularly complicated due to dynamic contextual factors, making it essential to ensure adequate coverage for all connected devices. Consequently, empirical channel modeling plays a pivotal role in understanding real-world behavior, which is characterized by a complex interplay of stationary and mobile elements. Given the highly directional nature of 60 GHz propagation, this study addresses a seemingly simple but important question: what is the impact of employing highly directive antennas when deviating from the line of sight? To address this question, we conducted an empirical measurement campaign of wireless channels within an office environment. Our assessment focused on power losses and distribution within an angular range while an indoor base station served indoor users, simulating the operation of an IEEE 802.11ad high-speed WLAN at 60 GHz. Additionally, we explored scenarios with and without pedestrian movement in the vicinity of wireless terminals. Our observations reveal the presence of significant antenna lobes even in obstructed links, indicating potential opportunities to use angular combiners or beamformers to enhance link availability and the data rate. This empirical study provides valuable information and channel parameters to simulate 60 GHz millimeter wave (mm-wave) links in indoor environments, paving the way for more efficient and robust wireless communication systems. Full article
(This article belongs to the Section Information and Communication Technologies)
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15 pages, 12982 KiB  
Article
Preparation of Gradient Polyurethane and Its Performance for Flexible Sensors
by Chuanqi Ning, Depeng Gong, Lili Wu, Wanyu Chen and Chaocan Zhang
Polymers 2024, 16(12), 1617; https://doi.org/10.3390/polym16121617 (registering DOI) - 7 Jun 2024
Abstract
Flexible sensors are prone to the problems of slow recovery rate and large residual strain in practical use. In this paper, a polyurethane functional composite with a gradient change in elastic modulus is proposed as a flexible sensor to meet the recovery rate [...] Read more.
Flexible sensors are prone to the problems of slow recovery rate and large residual strain in practical use. In this paper, a polyurethane functional composite with a gradient change in elastic modulus is proposed as a flexible sensor to meet the recovery rate and residual strain without affecting the motion. Different hard and soft segment ratios are used to synthesize a gradient polyurethane structure. The conductive percolation threshold was obtained between 45 wt% and 50 wt% of flake silver powder. Both gradient polyurethane and gradient polyurethane composites demonstrated that gradient materials can increase the recovery rate and reduce residual strain. The gradient polyurethane composites had a tensile strength of 3.26 MPa, an elastic modulus of 2.58 MPa, an elongation at break of 245%, a sensitivity coefficient of 1.20 at 0–25% deformation, a sensitivity coefficient of 11.38 at 25–75% deformation, a rate of recovery of 1.95 s at a time, and a resistance to fatigue (over 1000 cycles at a fixed strain of 20% showed a stable electrical response). The sensing performance under different cyclic strain frequencies was also investigated. The process has practical applications in the field of wearable skin motion and health monitoring. Full article
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10 pages, 3667 KiB  
Article
Chemical Bath Deposition of ZnO/ZnGa2O4 Core–Shell Nanowire Heterostructures Using Partial Chemical Conversion
by Guislain Hector, Estelle Appert, Hervé Roussel, Anna Bujak, Eirini Sarigiannidou and Vincent Consonni
Nanomaterials 2024, 14(12), 991; https://doi.org/10.3390/nano14120991 (registering DOI) - 7 Jun 2024
Abstract
The development of innovative heterostructures made of ZnO nanowires is of great interest for enhancing the performances of many devices in the fields of optoelectronics, photovoltaics, and energy harvesting. We report an original fabrication process to form ZnO/ZnGa2O4 core–shell nanowire [...] Read more.
The development of innovative heterostructures made of ZnO nanowires is of great interest for enhancing the performances of many devices in the fields of optoelectronics, photovoltaics, and energy harvesting. We report an original fabrication process to form ZnO/ZnGa2O4 core–shell nanowire heterostructures in the framework of the wet chemistry techniques. The process involves the partial chemical conversion of ZnO nanowires grown via chemical bath deposition into ZnO/ZnGa2O4 core–shell nanowire heterostructures with a high interface quality following their immersion in an aqueous solution containing gallium nitrate heated at a low temperature. The double-step process describing the partial chemical conversion relies on successive dissolution and reaction mechanisms. The present finding offers the possibility to fabricate ZnO/ZnGa2O4 core–shell nanowire heterostructures at low temperatures and over a wide variety of substrates with a large surface area, which is attractive for nanostructured solar cells, deep-UV photodetectors, and piezoelectric devices. Full article
(This article belongs to the Section Nanofabrication and Nanomanufacturing)
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14 pages, 4177 KiB  
Article
Influence of the Material Mechanical Properties on Cutting Surface Quality during Turning
by Il-Seok Kang and Tae-Ho Lee
Processes 2024, 12(6), 1171; https://doi.org/10.3390/pr12061171 (registering DOI) - 7 Jun 2024
Abstract
In cutting processing, the mechanical properties of the material are very important, and the optimal cutting conditions, depending on strength, hardness, and elongation, affect the quality of the machined surface. Therefore, this study was conducted to obtain optimized cutting conditions such as the [...] Read more.
In cutting processing, the mechanical properties of the material are very important, and the optimal cutting conditions, depending on strength, hardness, and elongation, affect the quality of the machined surface. Therefore, this study was conducted to obtain optimized cutting conditions such as the tool depth of the cut, cutting speed, and feed rate, considering the mechanical properties of the material. AISI 1045 cold-drawn (CD) bars showed an average tensile strength of 695.31 MPa in the tensile test and an average value of 308.6 HV in the Vickers hardness measurement. AISI 1020 CD bars showed a 22.66% lower average tensile strength of 537.74 MPa and an average of 198.77 HV in the hardness measurement. Therefore, AISI 1020 showed a 32.62% higher elongation than AISI 1045. In the measurement results for surface roughness after cutting, different results were observed depending on the strength and elongation at a feed rate of 0.05 mm/rev. AISI 1045 exhibited the highest machining quality, with a surface roughness of approximately 0.374 µm at a cutting speed of 150 m/min, and the cutting depth was 0.4 mm at a feed rate of 0.05 mm/rev. Alternatively, AISI 1020, which had relatively low strength and hardness with high elongation, exhibited the highest machining quality with a roughness of 0.383 µm with similar cutting parameters as AISI 1045. Full article
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16 pages, 745 KiB  
Article
Assessment of Factors Influencing Educational Effectiveness in Higher Educational Institutions
by Yurii Vasilev, Polina Vasileva, Olga Batova and Anna Tsvetkova
Sustainability 2024, 16(12), 4886; https://doi.org/10.3390/su16124886 (registering DOI) - 7 Jun 2024
Abstract
This paper discusses the results of the study of educational effectiveness at the tertiary level. It contains an overview of the research considering the quality and effectiveness of higher education development, the issues of creating criteria for their assessment and measurement. The four [...] Read more.
This paper discusses the results of the study of educational effectiveness at the tertiary level. It contains an overview of the research considering the quality and effectiveness of higher education development, the issues of creating criteria for their assessment and measurement. The four groups of factors (“Man”, “Milieu”, “Material”, “Method”) for evaluating educational effectiveness were determined, totally including 65 points. The results of the students’ surveys revealed the most significant factors as well as the least crucial ones influencing educational effectiveness in higher educational institutions. The total number of respondents was 279. It was found that the subgroup of factors “Teacher’s competence” is the most important from the viewpoint of the respondents, while the subgroup “Infrastructure facilities” is the least valuable one. The priority measures list was given, the implementation of which will make it possible to increase educational effectiveness in higher educational institutions. Methods such as Ishikawa diagram building, brainstorming and the survey of students were used for achieving the objectives of this research. Full article
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5 pages, 2050 KiB  
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Febrile Rash: An Early Diagnostic Clue to Infectious Illness in Travelers Returning from Thailand
by Hisham Ahmed Imad, Anastasia Putri, Ratchata Charoenwisedsil, Sakarn Charoensakulchai and Eric Caumes
Reports 2024, 7(2), 45; https://doi.org/10.3390/reports7020045 (registering DOI) - 7 Jun 2024
Abstract
The eruption of a rash along with spiking fever in travelers returning from the tropics may be suspicious of arboviral diseases, and isolation prevent further transmission in non-endemic countries. The case presented here was seen at the Fever Clinic at the Hospital for [...] Read more.
The eruption of a rash along with spiking fever in travelers returning from the tropics may be suspicious of arboviral diseases, and isolation prevent further transmission in non-endemic countries. The case presented here was seen at the Fever Clinic at the Hospital for Tropical Diseases in Bangkok, Thailand. The presenting complaints were fever, headache, myalgia, and a distinctive erythematous blanching rash. Despite a negative dengue NS1 test on the initial day, anti-dengue IgM and IgG were detectable on day five of illness. Dengue, a leading cause of traveler’s fever with rash, is of particular concern, especially during outbreaks like the one in Thailand in 2023, when the number of cases exceeded one hundred thousand over a nine-month period. The influx of 28 million travelers in 2023, many with naive immunity to many arboviruses, raises fear of transmission to temperate regions, including to countries like France, where Aedes albopictus establishment can lead to autochthonous dengue cases and clusters. Enhanced surveillance is crucial, urging the consideration of dengue as a potential diagnosis in travelers with febrile rash, even prior to lab confirmation. Immediate isolation of patients is essential to prevent autochthonous transmission, reduce outbreak risks, and avert public health crises. Full article
(This article belongs to the Collection Health Threats of Climate Change)
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17 pages, 4092 KiB  
Article
Multi-UAV Formation Path Planning Based on Compensation Look-Ahead Algorithm
by Tianye Sun, Wei Sun, Changhao Sun and Ruofei He
Drones 2024, 8(6), 251; https://doi.org/10.3390/drones8060251 (registering DOI) - 7 Jun 2024
Abstract
This study primarily studies the shortest-path planning problem for unmanned aerial vehicle (UAV) formations under uncertain target sequences. In order to enhance the efficiency of collaborative search in drone clusters, a compensation look-ahead algorithm based on optimizing the four-point heading angles is proposed. [...] Read more.
This study primarily studies the shortest-path planning problem for unmanned aerial vehicle (UAV) formations under uncertain target sequences. In order to enhance the efficiency of collaborative search in drone clusters, a compensation look-ahead algorithm based on optimizing the four-point heading angles is proposed. Building upon the receding-horizon algorithm, this method introduces the heading angles of adjacent points to approximately compensate and decouple the triangular equations of the optimal trajectory, and a general formula for calculating the heading angles is proposed. The simulation data indicate that the model using the compensatory look forward algorithm exhibits a maximum improvement of 12.9% compared to other algorithms. Furthermore, to solve the computational complexity and sample size requirements for optimal solutions in the Dubins multiple traveling salesman model, a path-planning model for multiple UAV formations is introduced based on the Euclidean traveling salesman problem (ETSP) pre-allocation. By pre-allocating sub-goals, the model reduces the computational scale of individual samples while maintaining a constant sample size. The simulation results show an 8.4% and 17.5% improvement in sparse regions for the proposed Euclidean Dubins traveling salesman problem (EDTSP) model for takeoff from different points. Full article
(This article belongs to the Special Issue Distributed Control, Optimization, and Game of UAV Swarm Systems)
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17 pages, 53744 KiB  
Article
Fractal Tent Map with Application to Surrogate Testing
by Ekaterina Kopets, Vyacheslav Rybin, Oleg Vasilchenko, Denis Butusov, Petr Fedoseev and Artur Karimov
Fractal Fract. 2024, 8(6), 344; https://doi.org/10.3390/fractalfract8060344 (registering DOI) - 7 Jun 2024
Abstract
Discrete chaotic maps are a mathematical basis for many useful applications. One of the most common is chaos-based pseudorandom number generators (PRNGs), which should be computationally cheap and controllable and possess necessary statistical properties, such as mixing and diffusion. However, chaotic PRNGs have [...] Read more.
Discrete chaotic maps are a mathematical basis for many useful applications. One of the most common is chaos-based pseudorandom number generators (PRNGs), which should be computationally cheap and controllable and possess necessary statistical properties, such as mixing and diffusion. However, chaotic PRNGs have several known shortcomings, e.g., being prone to chaos degeneration, falling in short periods, and having a relatively narrow parameter range. Therefore, it is reasonable to design novel simple chaotic maps to overcome these drawbacks. In this study, we propose a novel fractal chaotic tent map, which is a generalization of the well-known tent map with a fractal function introduced into the right-hand side. We construct and investigate a PRNG based on the proposed map, showing its high level of randomness by applying the NIST statistical test suite. The application of the proposed PRNG to the task of generating surrogate data and a surrogate testing procedure is shown. The experimental results demonstrate that our approach possesses superior accuracy in surrogate testing across three distinct signal types—linear, chaotic, and biological signals—compared to the MATLAB built-in randn() function and PRNGs based on the logistic map and the conventional tent map. Along with surrogate testing, the proposed fractal tent map can be efficiently used in chaos-based communications and data encryption tasks. Full article
(This article belongs to the Topic Recent Trends in Nonlinear, Chaotic and Complex Systems)
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13 pages, 4017 KiB  
Article
Effects of Oil Concentration in Flood Cooling on Cutting Force, Tool Wear and Surface Roughness in GTD-111 Nickel-Based Superalloy Slot Milling
by Gábor Kónya and Zsolt F. Kovács
J. Manuf. Mater. Process. 2024, 8(3), 119; https://doi.org/10.3390/jmmp8030119 (registering DOI) - 7 Jun 2024
Abstract
Cooling–lubricating processes have a big impact on cutting force, tool wear, and the quality of the machined surface, especially for hard-to-machine superalloys, so the choice of the right cooling–lubricating method is of great importance. Nickel-based superalloys are among the most difficult materials to [...] Read more.
Cooling–lubricating processes have a big impact on cutting force, tool wear, and the quality of the machined surface, especially for hard-to-machine superalloys, so the choice of the right cooling–lubricating method is of great importance. Nickel-based superalloys are among the most difficult materials to machine due to their high hot strength, work hardening, and extremely low thermal conductivity. Previous research has shown that flood cooling results in the least tool wear and cutting force among different cooling–lubricating methods. Thus, the effects of the flood oil concentration (3%; 6%; 9%; 12%; and 15%) on the above-mentioned factors were investigated during the slot milling of the GTD-111 nickel-based superalloy. The cutting force was measured during machining with a Kistler three-component dynamometer, and then after cutting the tool wear and the surface roughness on the bottom surface of the milled slots were measured with a confocal microscope and tactile roughness tester. The results show that at a 12% oil concentration, the tool load and tool wear are the lowest; even at an oil concentration of 15%, a slight increase is observed in both factors. Essentially, a higher oil concentration reduces friction between the tool and the workpiece contact surface, resulting in reduced tool wear and cutting force. Furthermore, due to less friction, the heat generation in the cutting zone is also reduced, resulting in a lower heat load on the tool, which increases tool life. It is interesting to note that the 6% oil concentration had the highest cutting force and tool wear, and strong vibration was heard during machining, which is also reflected in the force signal. The change in oil concentration did not effect the surface roughness. Full article
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24 pages, 376 KiB  
Article
Further Hermite–Hadamard-Type Inequalities for Fractional Integrals with Exponential Kernels
by Hong Li, Badreddine Meftah, Wedad Saleh, Hongyan Xu, Adem Kiliçman and Abdelghani Lakhdari
Fractal Fract. 2024, 8(6), 345; https://doi.org/10.3390/fractalfract8060345 (registering DOI) - 7 Jun 2024
Abstract
This paper introduces new versions of Hermite–Hadamard, midpoint- and trapezoid-type inequalities involving fractional integral operators with exponential kernels. We explore these inequalities for differentiable convex functions and demonstrate their connections with classical integrals. This paper validates the derived inequalities through a numerical example [...] Read more.
This paper introduces new versions of Hermite–Hadamard, midpoint- and trapezoid-type inequalities involving fractional integral operators with exponential kernels. We explore these inequalities for differentiable convex functions and demonstrate their connections with classical integrals. This paper validates the derived inequalities through a numerical example with graphical representations and provides some practical applications, highlighting their relevance to special means. This study presents novel results, offering new insights into classical integrals as the fractional order β approaches 1, in addition to the fractional integrals we examined. Full article
(This article belongs to the Special Issue New Trends on Generalized Fractional Calculus)
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