The 2023 MDPI Annual Report has
been released!
 
19 pages, 1556 KiB  
Article
State of Health Estimation for Lithium-Ion Battery Based on Sample Transfer Learning under Current Pulse Test
by Yuanyuan Li, Xinrong Huang, Jinhao Meng, Kaibo Shi, Remus Teodorescu and Daniel Ioan Stroe
Batteries 2024, 10(5), 156; https://doi.org/10.3390/batteries10050156 (registering DOI) - 02 May 2024
Abstract
Considering the diversity of battery data under dynamic test conditions, the stability of battery working data is affected due to the diversity of charge and discharge rates, variability of operating temperature, and randomness of the current state of charge, and the data types [...] Read more.
Considering the diversity of battery data under dynamic test conditions, the stability of battery working data is affected due to the diversity of charge and discharge rates, variability of operating temperature, and randomness of the current state of charge, and the data types are multi-sourced, which increases the difficulty of estimating battery SOH based on data-driven methods. In this paper, a lithium-ion battery state of health estimation method with sample transfer learning under dynamic test conditions is proposed. Through the Tradaboost.R2 method, the weight of the source domain sample data is adjusted to complete the update of the sample data distribution. At the same time, considering the division methods of the six auxiliary and the source domain data set, aging features from different state of charge ranges are selected. It is verified that while the aging feature dimension and the demand for target domain label data are reduced, the estimation accuracy of the lithium-ion battery state of health is not affected by the initial value of the state of charge. By considering the mean absolute error, mean square error and root mean square error, the estimated error results do not exceed 1.2% on the experiment battery data, which highlights the advantages of the proposed methods. Full article
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9 pages, 1990 KiB  
Article
Exploring the Severity Strata of Disease Activity and Repigmentation in Vitiligo Based on Validated Physician Global Assessment (PGA) Scores
by Nanja van Geel, Liesbeth Delbaere, Laura Mertens, Virginie Vandaele, Lien Depaepe, Jérôme Van Causenbroeck, Sofie De Schepper, Laura Van Coile, Astrid Van Reempts, Ann-Sophie De Vos, Jorien Papeleu, Isabelle Hoorens, Albert Wolkerstorfer and Reinhart Speeckaert
J. Clin. Med. 2024, 13(9), 2680; https://doi.org/10.3390/jcm13092680 (registering DOI) - 02 May 2024
Abstract
Background/Objectives: There is currently no guidance on how to interpret the global degrees of activity (worsening) and repigmentation (improvement) in vitiligo. Stratification into global degrees can be completed for static evaluations (e.g., visible disease activity signs) and dynamic assessments (e.g., evolution over time). [...] Read more.
Background/Objectives: There is currently no guidance on how to interpret the global degrees of activity (worsening) and repigmentation (improvement) in vitiligo. Stratification into global degrees can be completed for static evaluations (e.g., visible disease activity signs) and dynamic assessments (e.g., evolution over time). For the latter, the Vitiligo Disease Activity Score (VDAS15&60) and Vitiligo Disease Improvement Score (VDIS15&60) were recently validated. Methods: In the current study, a Physician Global Assessment (PGA) for disease activity (worsening) and repigmentation (improvement) was evaluated for validity (construct) and reliability (inter- and intrarater) based on a photo set of 66 patients. Subsequently, the PGA activity (worsening) and repigmentation (improvement) were used to stratify the Vitiligo Extent Score plus (VESplus), VDAS15&60 or VDIS15&60 into three global categories (slightly, moderately and much worse/improved), based on ROC analysis. Results: For the VESplus, cut-off values for the categories ‘slightly, moderately and much worse’ were >0.3%, >27.71% and >128.75% BSA (relative changes in the affected total BSA), respectively. For the categories ‘slightly, moderately and much improved’, they were >0%, >4.87% and >36.88% BSA (relative changes in the affected total BSA), respectively. The optimal cut-off values of the number of active (VDAS15) body areas were >0 areas for slightly worse, >2 areas for moderately worse and >7 for much worse. For VDIS15, the cut-off values for slightly improved and moderately improved were >0 and >1. For VDAS60 and VDIS60, the cut-off points were >0.5, >3, >9.5 and >0.5 and >1.5, respectively. The results should be interpreted with caution in patients with extensive vitiligo due to the rather limited disease extent of the included patient population (VESplus (median: 3.2%)). Conclusions: This research will aid in the development of more detailed international definitions. Full article
(This article belongs to the Special Issue Prevention and Treatment of Skin Pigmentation Disorders)
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17 pages, 1715 KiB  
Article
A Test of the Self-Medication Hypothesis Using a Latent Measurement Model: Are Stress and Impaired Control over Alcohol Mediating Mechanisms of Parenting Styles on Heavy Episodic Drinking and Alcohol-Related Problems among University Students?
by Felix B. Muniz, Elena Kalina, Julie A. Patock-Peckham, Sophia Berberian, Brittney Fulop, Jason Williams and Robert F. Leeman
Behav. Sci. 2024, 14(5), 384; https://doi.org/10.3390/bs14050384 (registering DOI) - 02 May 2024
Abstract
Introduction: The self-medication hypothesis (SMH) suggests that individuals consume alcohol to alleviate stressful emotions. Still, the underlying mechanisms between stress and heavy episodic drinking remain to be explored. Impaired control over drinking (IC) reflects a failure of self-regulation specific to the drinking context, [...] Read more.
Introduction: The self-medication hypothesis (SMH) suggests that individuals consume alcohol to alleviate stressful emotions. Still, the underlying mechanisms between stress and heavy episodic drinking remain to be explored. Impaired control over drinking (IC) reflects a failure of self-regulation specific to the drinking context, with individuals exceeding self-prescribed limits. Parenting styles experienced during childhood have a lasting influence on the stress response, which may contribute to IC. Method: We examined the indirect influences of parenting styles (e.g., permissive, authoritarian, and authoritative) on heavy episodic drinking and alcohol-related problems through the mediating mechanisms of stress and IC. We fit a latent measurement model with 938 (473 men; 465 women) university students, utilizing bootstrap confidence intervals, in Mplus 8.0. Results: Higher levels of authoritative parenting (mother and father) were indirectly linked to fewer alcohol-related problems and less heavy episodic drinking through less stress and IC. Maternal permissiveness was indirectly linked to more alcohol-related problems and heavy episodic drinking through more stress and, in turn, more IC. Impaired control appeared to be a mediator for stress and alcohol-related problems. Conclusions: Maternal permissiveness contributes to the use of alcohol to alleviate stress. Thus, reducing stress may reduce problematic heavy drinking and alcohol problems among emerging adults with high IC who may also have experienced permissive parenting. Stress may exacerbate behavioral dysregulation of drinking within self-prescribed limits. Full article
(This article belongs to the Special Issue Stress and Drinking)
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16 pages, 5608 KiB  
Article
Amelioration of Dextran Sodium Sulfate-Induced Colitis in Mice through Oral Administration of Palmitoylethanolamide
by Purvi Trivedi, Tanya Myers, Bithika Ray, Matthew Allain, Juan Zhou, Melanie Kelly and Christian Lehmann
Biomedicines 2024, 12(5), 1000; https://doi.org/10.3390/biomedicines12051000 (registering DOI) - 02 May 2024
Abstract
Inflammatory bowel disease (IBD) is a group of chronic disorders characterized by pain, ulceration, and the inflammation of the gastrointestinal tract (GIT) and categorized into two major subtypes: ulcerative colitis (UC) and Crohn’s disease. The inflammation in UC is typically restricted to the [...] Read more.
Inflammatory bowel disease (IBD) is a group of chronic disorders characterized by pain, ulceration, and the inflammation of the gastrointestinal tract (GIT) and categorized into two major subtypes: ulcerative colitis (UC) and Crohn’s disease. The inflammation in UC is typically restricted to the mucosal surface, beginning in the rectum and extending through the entire colon. UC patients typically show increased levels of pro-inflammatory cytokines, leading to intestinal epithelial apoptosis and mucosal inflammation, which impair barrier integrity. Chronic inflammation is associated with the rapid recruitment and inappropriate retention of leukocytes at the site of inflammation, further amplifying the inflammation. While UC can be managed using a number of treatments, these drugs are expensive and cause unwanted side effects. Therefore, a safe and effective treatment for UC patients is needed. Palmitoylethanolamide (PEA) is an endogenous fatty acid amide and an analog of the endocannabinoid anandamine. PEA administration has been found to normalize intestinal GIT motility and reduce injury in rodents and humans. In the current study, we examined the efficacy of PEA encapsulated in phytosomes following oral administration in experimental ulcerative colitis. Here, we showed that PEA at a human-equivalent dose of 123 mg/kg (OD or BID) attenuated DSS-induced experimental colitis as represented by the reduction in clinical signs of colitis, reduction in gross mucosal injury, and suppression of leukocyte recruitment at inflamed venules. These findings add to the growing body of data demonstrating the beneficial effects of PEA to control the acute phase of intestinal inflammation occurring during UC. Full article
(This article belongs to the Section Drug Discovery, Development and Delivery)
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13 pages, 270 KiB  
Article
New Model for Hill’s Problem in the Framework of Continuation Fractional Potential
by Elbaz I. Abouelmagd
Math. Comput. Appl. 2024, 29(3), 34; https://doi.org/10.3390/mca29030034 (registering DOI) - 02 May 2024
Abstract
In this work, we derived a new type model for spatial Hill’s system considering the created perturbation by the parameter effect of the continuation fractional potential. The new model is considered a reduced system from the restricted three-body problem under the same effect [...] Read more.
In this work, we derived a new type model for spatial Hill’s system considering the created perturbation by the parameter effect of the continuation fractional potential. The new model is considered a reduced system from the restricted three-body problem under the same effect for describing Hill’s problem. We identified the associated Lagrangian and Hamiltonian functions of the new system, and used them to verify the existence of the new equations of motion. We also proved that the new model has different six valid solutions under different six symmetries transformations as well as the original solution, where the new model is an invariant under these transformations. The several symmetries of Hill’s model can extremely simplify the calculation and analysis of preparatory studies for the dynamical behavior of the system. Finally, we confirm that these symmetries also authorize us to explore the similarities and differences among many classes of paths that otherwise differ from the obtained trajectories by restricted three-body problem. Full article
15 pages, 28225 KiB  
Article
Effect of Force and Heat Coupling on Machined Surface Integrity and Fatigue Performance of Superalloy GH4169 Specimens
by Xun Li, Ruijie Gou and Ning Zhang
Metals 2024, 14(5), 540; https://doi.org/10.3390/met14050540 (registering DOI) - 02 May 2024
Abstract
GH4169 is one of the key materials used to manufacture high-temperature load-bearing parts for aero-engines, and the surface integrity of these parts in service conditions significantly affects their high-temperature fatigue performance. Under a coupling effect of high temperature and alternating load, the evolution [...] Read more.
GH4169 is one of the key materials used to manufacture high-temperature load-bearing parts for aero-engines, and the surface integrity of these parts in service conditions significantly affects their high-temperature fatigue performance. Under a coupling effect of high temperature and alternating load, the evolution process of the machined surface integrity index of superalloy GH4169 specimens was studied, and fatigue performance tests at 20 °C, 450 °C, and 650 °C were carried out to analyze the primary factors affecting the high-temperature fatigue performance of specimens. The results indicated that the surface roughness of specimens remained essentially unchanged. However, the value of surface residual stress decreased significantly, with a release of more than 60% at the highest temperature. At 650 °C, the surface microhardness increased, while the degree of surface plastic deformation decreased under alternating loads. Simultaneously, when the surface roughness was less than Ra 0.4 μm, surface microhardness was the main factor affecting the high-temperature fatigue performance of specimens. The influence of surface microhardness on low-cycle fatigue performance was not consistent with that on high-cycle fatigue performance. The latter increased monotonically, whereas the former initially increased and then decreased with increasing surface microhardness. Full article
(This article belongs to the Special Issue Advances in Lightweight Alloys)
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24 pages, 7045 KiB  
Article
Phenotyping Wheat Kernel Symmetry as a Consequence of Different Agronomic Practices
by Tatiana S. Aniskina, Kirill A. Sudarikov, Nikita A. Prisazhnoy, Ishen N. Besaliev, Alexander A. Panfilov, Nelli S. Reger, Tatyana Kormilitsyna, Antonina A. Novikova, Alexander A. Gulevich, Svyatoslav V. Lebedev, Pyotr A. Vernik and Ekaterina N. Baranova
Symmetry 2024, 16(5), 548; https://doi.org/10.3390/sym16050548 (registering DOI) - 02 May 2024
Abstract
The use of instrumental methods of analysis in the assessment of indices that record changes in symmetry in the structure of grains to evaluate the quality of durum and soft wheat grain is currently considered a search tool that will allow us to [...] Read more.
The use of instrumental methods of analysis in the assessment of indices that record changes in symmetry in the structure of grains to evaluate the quality of durum and soft wheat grain is currently considered a search tool that will allow us to obtain previously unavailable data by finding correlations associated with differences in the shape and ratio of starch granules in conditionally symmetrical and asymmetrical wheat fruits (kernels) formed in different field conditions and with different genotypes. Indicators that had previously shown their effectiveness were used to analyze the obviously complex unique material obtained as a result of growing under critically unique sowing conditions in 2022, which affected the stability of grain development and filling. For the evaluation, a typical agronomic comparative experiment was chosen, which was used to evaluate the soil tillage practices (fallow, non-moldboard loosening, and plowing) and sowing dates (early and after excessive rainfalls), which made it possible to analyze a wider range of factors influencing the studied indices. The soil tillage methods were found to affect the uniformity of kernel fullness and their symmetry, and the sowing dates did not lead to significant differences. This study presents detailed changes in the shape of the middle cut of a wheat kernel, associated with assessing the efficiency of kernel filling and the symmetrical distribution of storage substances under the influence of external and internal physical factors that affect the formation of the wheat kernel. The data obtained may be of interest to breeders and developers of predictive phenotyping programs for cereal grain and seeds of other crops, as well as plant physiologists. Full article
(This article belongs to the Special Issue Symmetry/Asymmetry in Life Sciences: Feature Papers 2024)
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, Daniel De-Shing Chen, Tzu-Yu Peng and Johnson 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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21 pages, 4006 KiB  
Article
Ukrainian Women’s Entrepreneurship and Business Ecosystem during the War: New Challenges for Development
by Tetiana Stroiko, Patricia P. Iglesias-Sanchez, Carmen Jambrino-Maldonado, Elena Fernández-Díaz and Carlos de las Heras-Pedrosa
Sustainability 2024, 16(9), 3829; https://doi.org/10.3390/su16093829 (registering DOI) - 02 May 2024
Abstract
This research focuses on the key aspects of the basis of women’s entrepreneurship in the particular case of the Ukrainian ecosystem of entrepreneurship. Even in wartime, entrepreneurship is a chance to overcome circumstances, and it should be developed for women and men. A [...] Read more.
This research focuses on the key aspects of the basis of women’s entrepreneurship in the particular case of the Ukrainian ecosystem of entrepreneurship. Even in wartime, entrepreneurship is a chance to overcome circumstances, and it should be developed for women and men. A correlation regression analysis and simulation modeling were carried out in order to rank the priorities for the development of types of economic activity of small business entities managed by women, making it possible to substantiate the forecast of the development of women’s entrepreneurship in Ukraine for 2024–2026. The findings show the positive impact of the entrepreneurial ecosystem and the need to continue to strengthen policies that encourage and facilitate female entrepreneurship. This analysis provides three types of development scenarios for women’s entrepreneurship in Ukraine. Full article
15 pages, 902 KiB  
Article
Enhancing Bitcoin Price Volatility Estimator Predictions: A Four-Step Methodological Approach Utilizing Elastic Net Regression
by Georgia Zournatzidou, Ioannis Mallidis, Dimitrios Farazakis and Christos Floros
Mathematics 2024, 12(9), 1392; https://doi.org/10.3390/math12091392 (registering DOI) - 02 May 2024
Abstract
This paper provides a computationally efficient and novel four-step methodological approach for predicting volatility estimators derived from bitcoin prices. In the first step, open, high, low, and close bitcoin prices are transformed into volatility estimators using Brownian motion assumptions and logarithmic transformations. The [...] Read more.
This paper provides a computationally efficient and novel four-step methodological approach for predicting volatility estimators derived from bitcoin prices. In the first step, open, high, low, and close bitcoin prices are transformed into volatility estimators using Brownian motion assumptions and logarithmic transformations. The second step determines the optimal number of time-series lags required for converting the series into an autoregressive model. This selection process utilizes random forest regression, evaluating the importance of each lag using the Mean Decrease in Impurity (MDI) criterion and optimizing the number of lags considering an 85% cumulative importance threshold. The third step of the developed methodological approach fits the Elastic Net Regression (ENR) to the volatility estimator’s dataset, while the final fourth step assesses the predictive accuracy of ENR, compared to decision tree (DTR), random forest (RFR), and support vector regression (SVR). The results reveal that the ENR prevails in its predictive accuracy for open and close prices, as these prices may be linear and less susceptible to sudden, non-linear shifts typically seen during trading hours. On the other hand, SVR prevails for high and low prices as these prices often experience spikes and drops driven by transient news and intra-day market sentiments, forming complex patterns that do not align well with linear modelling. Full article
17 pages, 4159 KiB  
Article
Estimation of Random Coefficient Autoregressive Model with Error in Covariates
by Xiaolei Zhang, Jin Chen and Qi Li
Axioms 2024, 13(5), 303; https://doi.org/10.3390/axioms13050303 (registering DOI) - 02 May 2024
Abstract
Measurement error is common in many statistical problems and has received considerable attention in various regression contexts. In this study, we consider the random coefficient autoregressive model with measurement error possibly present in covariates. The least squares and weighted least squares methods are [...] Read more.
Measurement error is common in many statistical problems and has received considerable attention in various regression contexts. In this study, we consider the random coefficient autoregressive model with measurement error possibly present in covariates. The least squares and weighted least squares methods are used to estimate the model parameters, and the consistency and asymptotic normality of the two kinds of estimators are proved. Furthermore, we propose an empirical likelihood method based on weighted score equations to construct confidence regions for the parameters. The simulation results show that the weighted least squares estimators are superior to the least squares estimators and that the confidence regions have good finite-sample behavior. At last, the model is applied to a real data example. Full article
(This article belongs to the Special Issue Time Series Analysis: Research on Data Modeling Methods)
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22 pages, 4071 KiB  
Article
An Internet of Things-Based Production Scheduling for Distributed Two-Stage Assembly Manufacturing with Mold Sharing
by Yin Liu, Cunxian Ma and Yun Huang
Machines 2024, 12(5), 310; https://doi.org/10.3390/machines12050310 (registering DOI) - 02 May 2024
Abstract
In digital product and ion scheduling centers, order–factory allocation, factory–mold allocation, and mold routing can be performed centrally and efficiently to maximize the utilization of manufacturing resources (molds). Therefore, in this paper, a manufacturing resource (molds)-sharing mechanism based on the Internet of Things [...] Read more.
In digital product and ion scheduling centers, order–factory allocation, factory–mold allocation, and mold routing can be performed centrally and efficiently to maximize the utilization of manufacturing resources (molds). Therefore, in this paper, a manufacturing resource (molds)-sharing mechanism based on the Internet of Things (IoT) and a cyber-physical production system (CPPS) is designed to realize the coordinated allocation of molds and production scheduling. A mixed-integer mathematical model is developed to optimize the cost structure and obtain a reasonable profit solution. A heuristic algorithm based on evolutionary reversal is used to solve the problem. The numerical results show that based on the digital coordinated production scheduling method, distributed two-stage assembly manufacturing with shared molds can effectively reduce the order delay time and increase potential benefits for distributed production enterprises. Full article
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17 pages, 5070 KiB  
Article
Abnormal Static Sagittal Cervical Curvatures following Motor Vehicle Collisions: A Retrospective Case Series of 41 Patients before and after a Crash Exposure
by Jason W. Haas, Paul A. Oakley, Joseph R. Ferrantelli, Evan A. Katz, Ibrahim M. Moustafa and Deed E. Harrison
Diagnostics 2024, 14(9), 957; https://doi.org/10.3390/diagnostics14090957 (registering DOI) - 02 May 2024
Abstract
Previous investigations have found a correlation between abnormal curvatures and a variety of patient complaints such as cervical pain and disability. However, no study has shown that loss of the cervical curve is a direct result of exposure to a motor vehicle collision [...] Read more.
Previous investigations have found a correlation between abnormal curvatures and a variety of patient complaints such as cervical pain and disability. However, no study has shown that loss of the cervical curve is a direct result of exposure to a motor vehicle collision (MVC). This investigation presents a retrospective consecutive case series of patients with both a pre-injury cervical lateral radiograph (CLR) and a post-injury CLR after exposure to an MVC. Computer analysis of digitized vertebral body corners on CLRs was performed to investigate the possible alterations in the geometric alignment of the sagittal cervical curve. Methods: Three spine clinic records were reviewed over a 2-year period, looking for patients where both an initial lateral cervical X-ray and an examination were performed prior to the patient being exposed to a MVC; afterwards, an additional exam and radiographic analysis were obtained. A total of 41 patients met the inclusion criteria. Examination records of pain intensity on numerical pain rating scores (NPRS) and neck disability index (NDI), if available, were analyzed. The CLRs were digitized and modeled in the sagittal plane using curve fitting and the least squares error approach. Radiographic variables included total cervical curve (ARA C2–C7), Chamberlain’s line to horizontal (skull flexion), horizontal translation of C2 relative to C7, segmental translations (retrolisthesis and anterolisthesis), and circular modelling radii. Results: There were 15 males and 26 females with an age range of 8–65 years. Most participants were drivers (28) involved in rear-end impacts (30). The pre-injury NPRS was 2.7 while the post injury was 5.0; p < 0.001. The NDI was available on 24/41 (58.5%) patients and increased after the MVC from 15.7% to 32.8%, p < 0.001. An altered cervical curvature was identified following exposure to MVC, characterized by an increase in the mean radius of curvature (265.5 vs. 555.5, p < 0.001) and an approximate 8° reduction of lordosis from C2–C7; p < 0.001. The mid-cervical spine (C3–C5) showed the greatest curve reduction with an averaged localized mild kyphosis at these levels. Four participants (10%) developed segmental translations that were just below the threshold of instability, segmental translations < 3.5 mm. Conclusions: The post-exposure MVC cervical curvature was characterized by an increase in radius of curvature, an approximate 8° reduction in C2–C7 lordosis, a mild kyphosis of the mid-cervical spine, and a slight increase in anterior translation of C2–C7 sagittal balance. The modelling result indicates that the post-MVC cervical sagittal alignment approximates a second-order buckling alignment, indicating a significant alteration in curve geometry. Future biomechanics experiments and clinical investigations are needed to confirm these findings. Full article
(This article belongs to the Special Issue Imaging Diagnosis in Musculoskeletal Medicine)
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21 pages, 7968 KiB  
Article
Choosing the Most Suitable Working Fluid for a CTEC
by Aliet Achkienasi, Rodolfo Silva, Edgar Mendoza and Luis D. Luna
Energies 2024, 17(9), 2181; https://doi.org/10.3390/en17092181 (registering DOI) - 02 May 2024
Abstract
This study aims to explore additional fluids beneficial for coastal thermal energy converter (CTEC) operation. Ammonia’s thermodynamic properties, characterized by higher condensation temperatures and pressures, demand significantly elevated operating pressures, resulting in a substantial energy load for efficient operation. Thus, exploring alternatives such [...] Read more.
This study aims to explore additional fluids beneficial for coastal thermal energy converter (CTEC) operation. Ammonia’s thermodynamic properties, characterized by higher condensation temperatures and pressures, demand significantly elevated operating pressures, resulting in a substantial energy load for efficient operation. Thus, exploring alternatives such as R134a becomes crucial, particularly considering its potential as a better working fluid for power generation in a Rankine cycle. The research methodology involves employing computational fluid dynamics (CFD) simulations alongside experimental investigations to examine the performance of an axial turbine concept under different working fluids. The results obtained indicate that R134a is the most appropriate working fluid for an axial turbine within a CTEC, outperforming ammonia, thereby implying significantly better operational efficiency. Full article
(This article belongs to the Section A3: Wind, Wave and Tidal Energy)
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12 pages, 468 KiB  
Brief Report
Osteonecrosis of the Jaw Associated with Bisphosphonates Infusion for Treatment of Plasma Cell Myeloma—A Retrospective Observational Study of Northern Portuguese Population
by Sara Sousa Ferreira, José Barbas do Amaral, José Júlio Pacheco, Filomena Salazar and Luís Monteiro
J. Clin. Med. 2024, 13(9), 2679; https://doi.org/10.3390/jcm13092679 (registering DOI) - 02 May 2024
Abstract
To verify medication-related osteonecrosis of the jaw (MRONJ) frequency among patients with plasma cell myeloma (PCM) that had been treated with bisphosphonates, to identify predisposing factors that could influence the development of osteonecrosis. Methods: This observational retrospective study was performed at the [...] Read more.
To verify medication-related osteonecrosis of the jaw (MRONJ) frequency among patients with plasma cell myeloma (PCM) that had been treated with bisphosphonates, to identify predisposing factors that could influence the development of osteonecrosis. Methods: This observational retrospective study was performed at the Department of Hematology of Hospital Center of Porto (CHUP), Portugal. Results: The study population (n = 112) had a 15.2% (n = 17) prevalence of osteonecrosis. Clinically, bone exposure was the most frequently observed sign, present in 100% (n = 17) of the patients, followed by inflammation in 82.4% (n = 14), orofacial pain in 70.6% (n = 12), suppuration in 47.1% (n = 8), and intra or extra-oral fistula in 17.6% (n = 3) of the cases. The most frequent triggering local factor was dental extraction (82.4%). There was a dependence between the presence of extractions and the development of MRONJ (p < 0.001) but not with the time elapsed from the initiation of infusions with BPs and dental extractions (p = 0.499). In the sample of patients with multiple myeloma (MM), 13.8% were found to be more likely to develop MRONJ after an extraction. Conclusions: The most common local predisposing factor was dental extraction. No dependence was observed between the development of osteonecrosis and the time elapsed from the beginning of treatment with bisphosphonates infusions to surgical procedures. Full article
22 pages, 682 KiB  
Article
Application of Fuzzy Control and Neural Network Control in the Commercial Development of Sustainable Energy System
by Fanbao Xie, Xin Guan, Xiaoyan Peng, Yanzhao Zeng, Zeyu Wang and Tianqiao Qin
Sustainability 2024, 16(9), 3823; https://doi.org/10.3390/su16093823 (registering DOI) - 02 May 2024
Abstract
Sustainable energy systems (SESs) occupy a prominent position in the modern global energy landscape. The purpose of this study is to explore the application of fuzzy control and neural network control in photovoltaic systems to improve the power generation efficiency and stability of [...] Read more.
Sustainable energy systems (SESs) occupy a prominent position in the modern global energy landscape. The purpose of this study is to explore the application of fuzzy control and neural network control in photovoltaic systems to improve the power generation efficiency and stability of the system. By establishing the mathematical model of a photovoltaic system, the nonlinear and uncertain characteristics of photovoltaic system are considered. Fuzzy control and neural network control are used to control the system, and their performance is verified by experiments. The experimental results show that under the conditions of low light and moderate temperature, the fuzzy neural network control achieves a 3.33% improvement in power generation efficiency compared with the single control strategy. Meanwhile, the system can still maintain relatively stable operation under different environmental conditions under this comprehensive control. This shows that fuzzy neural network control has significant advantages in improving power generation efficiency and provides beneficial technical support and guidance for the commercial development of SESs. Full article
13 pages, 4598 KiB  
Article
Li4SiO4-Based Heat Carrier Derived from Different Silica Sources for Thermochemical Energy Storage
by Xicheng Wang, Wentao Xia, Wenlong Xu, Zengqiao Chen, Xiaohan Ren and Yuandong Yang
Energies 2024, 17(9), 2180; https://doi.org/10.3390/en17092180 (registering DOI) - 02 May 2024
Abstract
Thermochemical energy storage (TCES) is one of the key technologies facilitating the integration of renewable energy sources and mitigating the climate crisis. Recently, Li4SiO4 has been reported to be a promising heat carrier material for TCES applications, owing to its [...] Read more.
Thermochemical energy storage (TCES) is one of the key technologies facilitating the integration of renewable energy sources and mitigating the climate crisis. Recently, Li4SiO4 has been reported to be a promising heat carrier material for TCES applications, owing to its moderate operation temperature and stability. During the synthetic processes, the properties of the Si source used directly influence the performance of derived Li4SiO4 materials; however, the internal relations and effects are not yet clear. Hence, in this work, six kinds of SiO2 sources with different phases, morphology, particle size, and surface area were selected to synthesize a Li4SiO4-based TCES heat carrier. The physicochemical properties of the SiO2 and the corresponding derived Li4SiO4 were characterized, and the comprehensive performance (e.g., heat storage/releasing capacity, rate, and cyclic stability) of the Li4SiO4 samples was systematically tested. It was found that the silica microspheres (SPs), which possess an amorphous phase, uniform micro-scale structure, and small particle size, could generate Li4SiO4 TCES materials with a highest initial capacity of 777.7 kJ/kg at 720 °C/900 °C under pure CO2. As a result, the SP-L showed an excellent cumulative heat storage amount of 5.84 MJ/kg within 10 heat-releasing/storage cycles, which was nearly 1.5 times greater than the value of Li4SiO4 derived from commonly used silicon dioxide. Furthermore, the effects of the utilized Si source on the performance of as-prepared Li4SiO4 and corresponding mechanisms were discussed, which offers guidance for the future selection of Si sources to produce high-performance Li4SiO4-based TCES heat carriers. Full article
(This article belongs to the Section D: Energy Storage and Application)
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28 pages, 1219 KiB  
Article
SMEs Awareness and Preparation for Digital Transformation: Exploring Business Opportunities for Entrepreneurs in Saudi Arabia’s Ha’il Region
by Abhishek Tripathi and Ajay Singh
Sustainability 2024, 16(9), 3831; https://doi.org/10.3390/su16093831 (registering DOI) - 02 May 2024
Abstract
This study investigates how Saudi SMEs’ awareness and preparation for digital transformation impact their business performance (BP). First and foremost, in this study, we examine the impact of awareness and preparation on business performance using the intention to use (ITU) as an initial [...] Read more.
This study investigates how Saudi SMEs’ awareness and preparation for digital transformation impact their business performance (BP). First and foremost, in this study, we examine the impact of awareness and preparation on business performance using the intention to use (ITU) as an initial mediator. In addition, the researchers also examined the impact of awareness and preparation on business performance through intention to use and Government Support (GS), and later, intention to use and skills as serial mediators. Using a structured questionnaire based on a seven-point Likert scale, data were collected from 68 SMEs in the Ha’il region of Saudi Arabia, one of the Kingdom’s leading economic provinces. The data were analyzed through simple and serial mediation techniques through AMOS-24. The study found that SMEs’ awareness and preparation for digital transformation significantly and positively influenced their intentions to use the technology. The researchers found that intention to use, skills, and government support are significant variables that improve business performance. The research also revealed full-serial mediation between awareness and business performance and preparation and business performance, showing that intention to use and skills and intention to use and government support significantly mediate improving SMEs’ business performance. The study implications provide for SMEs’ successful digital transformation, considering the role of skills and government support, which will help SMEs improve their performance and embrace sustainability in human and economic development in Saudi Arabia. Together with policymakers, SMEs, and researchers, it will also look at the entrepreneurial potential for Saudi nationals in the run-up to Vision 2030. Full article
12 pages, 3242 KiB  
Article
Characterization of Chitosan Hydrogels Obtained through Phenol and Tripolyphosphate Anionic Crosslinking
by Mitsuyuki Hidaka, Masaru Kojima, Shinji Sakai and Cédric Delattre
Polymers 2024, 16(9), 1274; https://doi.org/10.3390/polym16091274 (registering DOI) - 02 May 2024
Abstract
Chitosan is a deacetylated polymer of chitin that is extracted mainly from the exoskeleton of crustaceans and is the second-most abundant polymer in nature. Chitosan hydrogels are preferred for a variety of applications in bio-related fields due to their functional properties, such as [...] Read more.
Chitosan is a deacetylated polymer of chitin that is extracted mainly from the exoskeleton of crustaceans and is the second-most abundant polymer in nature. Chitosan hydrogels are preferred for a variety of applications in bio-related fields due to their functional properties, such as antimicrobial activity and wound healing effects; however, the existing hydrogelation methods require toxic reagents and exhibit slow gelation times, which limit their application in biological fields. Therefore, a mild and rapid gelation method is necessary. We previously demonstrated that the visible light-induced gelation of chitosan obtained through phenol crosslinking (ChPh) is a rapid gelation method. To further advance this method (<10 s), we propose a dual-crosslinked chitosan hydrogel obtained by crosslinking phenol groups and crosslinking sodium tripolyphosphate (TPP) and the amino groups of chitosan. The chitosan hydrogel was prepared by immersing the ChPh hydrogel in a TPP solution after phenol crosslinking via exposure to visible light. The physicochemical properties of the dual-crosslinked hydrogels, including Young’s moduli and water retentions, were subsequently investigated. Young’s moduli of the dual-crosslinked hydrogels were 20 times higher than those of the hydrogels without TPP ion crosslinking. The stiffness could be manipulated by varying the immersion time, and the water retention properties of the ChPh hydrogel were improved by TPP crosslinking. Ion crosslinking could be reversed using an iron chloride solution. This method facilitates chitosan hydrogel use for various applications, particularly tissue engineering and drug delivery. Full article
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14 pages, 2093 KiB  
Article
A Double-Threshold Cooperative Spectrum Sensing Algorithm in the Internet of Vehicles
by Hong Du and Yuhan Wang
World Electr. Veh. J. 2024, 15(5), 195; https://doi.org/10.3390/wevj15050195 (registering DOI) - 02 May 2024
Abstract
To address the shortage of wireless spectrum resources caused by the rapid development of the Internet of Vehicles, spectrum sensing technology in cognitive radio is employed to tackle this issue. In pursuit of superior outcomes, a double-threshold cooperative spectrum sensing algorithm is introduced. [...] Read more.
To address the shortage of wireless spectrum resources caused by the rapid development of the Internet of Vehicles, spectrum sensing technology in cognitive radio is employed to tackle this issue. In pursuit of superior outcomes, a double-threshold cooperative spectrum sensing algorithm is introduced. This algorithm enhances traditional energy detection technology to mitigate the high sensitivity to noise interference in the Internet of Vehicles environment. A double-threshold judgment mechanism can be established based on the uncertainty of noise. Varying fusion rules are implemented in the collaborative spectrum sensing scheme according to the density of vehicles and the spectrum resource demand. Simulation results demonstrate that the performance of the double-threshold cooperative spectrum sensing algorithm surpasses that of the traditional single-threshold energy detection scheme, particularly evident under lower Signal-to-Noise Ratio (SNR) conditions. Moreover, the proposed algorithm exhibits superior sensing performance in environments characterized by higher noise uncertainty. Full article
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24 pages, 15240 KiB  
Article
Enhancing Seismic Landslide Susceptibility Analysis for Sustainable Disaster Risk Management through Machine Learning
by Hailang He, Weiwei Wang, Zhengxing Wang, Shu Li and Jianguo Chen
Sustainability 2024, 16(9), 3828; https://doi.org/10.3390/su16093828 (registering DOI) - 02 May 2024
Abstract
The accuracy of Seismic Landslide Susceptibility Maps (SLSMs) is imperative for the prevention of seismic landslide disasters. This study enhances the precision of SLSMs by integrating nine distinct machine learning methodologies with the GeoDetector version 0.0.4 tool to filter both numerical and physical [...] Read more.
The accuracy of Seismic Landslide Susceptibility Maps (SLSMs) is imperative for the prevention of seismic landslide disasters. This study enhances the precision of SLSMs by integrating nine distinct machine learning methodologies with the GeoDetector version 0.0.4 tool to filter both numerical and physical factors contributing to landslide susceptibility. The dataset comprises 2317 landslide instances triggered by the 2013 Minxian Ms = 6.6 earthquake, from which redundant factors were pruned using the Recursive Feature Elimination technique. Subsequent evaluations of the optimized factors, both individually and in combination, were conducted through Frequency Ratio analysis and Factor Interaction assessment. The study juxtaposes the Area Under the Receiver Operating Characteristic Curve (AUC) and the accuracy of nine machine learning models before and after factor optimization. The findings indicate an increase in AUC from a maximum of 0.989 to 0.992 in the Random Forest model, and an 8.37% increase in AUC for the SVM model, signifying a notable enhancement in the stability across all models. The establishment of the SLSM notably elevated the frequency ratio in high-risk zones from 50.40 to 85.14, underscoring the efficacy of combining machine learning and detector optimization techniques in sustainable practices. This research proposes a universal framework aimed at eliminating redundancy and noise in SLSMs and hazard risk assessments, thereby facilitating sustainable geological disaster risk management. Full article
19 pages, 6386 KiB  
Article
Directional Multi-Resonant Micro-Electromechanical System Acoustic Sensor for Low Frequency Detection
by Justin Ivancic and Fabio Alves
Sensors 2024, 24(9), 2908; https://doi.org/10.3390/s24092908 (registering DOI) - 02 May 2024
Abstract
This paper reports on the design, modeling, and characterization of a multi-resonant, directional, MEMS acoustic sensor. The design builds on previous resonant MEMS sensor designs to broaden the sensor’s usable bandwidth while maintaining a high signal-to-noise ratio (SNR). These improvements make the sensor [...] Read more.
This paper reports on the design, modeling, and characterization of a multi-resonant, directional, MEMS acoustic sensor. The design builds on previous resonant MEMS sensor designs to broaden the sensor’s usable bandwidth while maintaining a high signal-to-noise ratio (SNR). These improvements make the sensor more attractive for detecting and tracking sound sources with acoustic signatures that are broader than discrete tones. In-air sensor characterization was conducted in an anechoic chamber. The sensor was characterized underwater in a semi-anechoic pool and in a standing wave tube. The sensor demonstrated a cosine-like directionality, a maximum acoustic sensitivity of 47.6 V/Pa, and a maximum SNR of 88.6 dB, for 1 Pa sound pressure, over the bandwidth of the sensor circuitry (100 Hz–3 kHz). The presented design represents a significant improvement in sensor performance compared to similar resonant MEMS sensor designs. Increasing the sensitivity of a single-resonator design is typically associated with a decrease in bandwidth. This multi-resonant design overcomes that limitation. Full article
(This article belongs to the Special Issue Acoustic Sensing and Monitoring in Urban and Natural Environments)
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16 pages, 2400 KiB  
Article
Impact of Silver Nanoparticles on Arbuscular Mycorrhizal Fungi and Glomalin-Related Soil Proteins in the Rhizosphere of Maize Seedlings
by Haiying Zhao, Zhiyuan Liu, Yu Han and Jiling Cao
Diversity 2024, 16(5), 273; https://doi.org/10.3390/d16050273 (registering DOI) - 02 May 2024
Abstract
Glomalin-related soil protein (GRSP), an important arbuscular mycorrhizal (AM) fungal by-product, plays a key role in preserving or sequestrating soil organic carbon (C). Silver nanoparticles (AgNPs) have become an emerging contaminant and their impacts on soil ecosystems attract increasing concerns. The dynamics of [...] Read more.
Glomalin-related soil protein (GRSP), an important arbuscular mycorrhizal (AM) fungal by-product, plays a key role in preserving or sequestrating soil organic carbon (C). Silver nanoparticles (AgNPs) have become an emerging contaminant and their impacts on soil ecosystems attract increasing concerns. The dynamics of AM fungi and GRSP could therefore form the basis for an in-depth exploration of the influences of AgNPs on soil ecosystems. This study investigated the effects of AgNPs on mycorrhizal growth and AM fungal communities, as well as the GRSP contents in maize (Zea mays L.) soils, with a pot experiment. The contributions of GRSP to soil organic C and the correlations of GRSP with soil organic C were also evaluated. The results indicated that AgNPs decreased the mycorrhizal colonization, AM fungal biomass, and diversity indices, and strongly shifted the community composition of AM fungi with a reduction in Acaulosporaceae and an enrichment in Glomeraceae. Additionally, AgNPs also decreased the soil’s easily extractable (EE) GRSP and total (T) GRSP contents, resulting in lower contributions of EE-GRSP-C and T-GRSP-C to the soil organic C. Linkage analyses revealed that AM fungal abundances have positive correlations with EE- and T-GRSP, and EE- and T-GRSP also positively correlated with soil organic C, indicating that the negative effects of AgNPs on AM fungal abundances and communities were extended to AM-fungal-associated C processes. Altogether, our study found that AgNPs decreased the AM fungal abundances shaped AM fungal communities, and reduced the soil GRSP content, which might subsequently be unfavorable for soil C storage. Full article
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