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16 pages, 2413 KiB  
Article
The Effect of Cannabidiol in Conjunction with Radiation Therapy on Canine Glioma Cell Line Transplanted in Immunodeficient Mice
by Masayasu Ukai, Jade Kurihara, Markos Antonakakis, Krista Banks, Steve Dow, Daniel L. Gustafson, Mary-Keara Boss, Amber Prebble and Stephanie McGrath
Vet. Sci. 2025, 12(8), 735; https://doi.org/10.3390/vetsci12080735 (registering DOI) - 5 Aug 2025
Abstract
Glioma is a type of neoplasia that spontaneously arises from the glial cells of the brain in humans and dogs, and its prognosis is grave. Current treatment options for glioma include surgery, radiation therapy, chemotherapy, or symptomatic treatment. Evidence has shown that cannabidiol [...] Read more.
Glioma is a type of neoplasia that spontaneously arises from the glial cells of the brain in humans and dogs, and its prognosis is grave. Current treatment options for glioma include surgery, radiation therapy, chemotherapy, or symptomatic treatment. Evidence has shown that cannabidiol (CBD) may have anticancer, anti-angiogenic, and anti-inflammatory properties in both in vitro and in vivo studies. In this in vivo murine experiment, the canine glioma cell line J3TBG was injected into the frontoparietal cortex of immunodeficient mice using xenogeneic tissue transplantation. A total of 20 mice were randomly assigned to one of four treatment groups—Control group (C), CBD group (CBD), Radiation Therapy group (RT), and CBD plus Radiation Therapy group (CBD + RT). After transplantation of J3TBG, a single fraction of 5.5 Gy RT was administered to the RT and CBD + RT groups, and CBD was administered daily to the CBD and CBD + RT groups. Necropsies were performed to collect blood and brain tissue. Although there was not a statistically significant difference, the survival time among mice were longer in the CBD + RT group than the RT group. These results indicate that CBD may be used as an adjunctive therapy to enhance RT treatment. Larger cohort studies are required to substantiate the hypothesis. Full article
(This article belongs to the Section Veterinary Biomedical Sciences)
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22 pages, 7171 KiB  
Article
Distribution Characteristics, Mobility, and Influencing Factors of Heavy Metals at the Sediment–Water Interface in South Dongting Lake
by Xiaohong Fang, Xiangyu Han, Chuanyong Tang, Bo Peng, Qing Peng, Linjie Hu, Yuru Zhong and Shana Shi
Water 2025, 17(15), 2331; https://doi.org/10.3390/w17152331 - 5 Aug 2025
Abstract
South Dongting Lake is an essential aquatic ecosystem that receives substantial water inflows from the Xiangjiang and Zishui Rivers. However, it is significantly impacted by human activities, including mining, smelting, and farming. These activities have led to serious contamination of the lake’s sediments [...] Read more.
South Dongting Lake is an essential aquatic ecosystem that receives substantial water inflows from the Xiangjiang and Zishui Rivers. However, it is significantly impacted by human activities, including mining, smelting, and farming. These activities have led to serious contamination of the lake’s sediments with heavy metals (HMs). This study investigated the distribution, mobility, and influencing factors of HMs at the sediment–water interface. To this end, sediment samples were analyzed from three key regions (Xiangjiang River estuary, Zishui River estuary, and northeastern South Dongting Lake) using traditional sampling methods and Diffusive Gradients in Thin Films (DGT) technology. Analysis of fifteen HMs (Pb, Bi, Ni, As, Se, Cd, Sb, Mn, Zn, V, Cr, Cu, Tl, Co, and Fe) revealed significant spatial heterogeneity. The results showed that Cr, Cu, Pb, Bi, Ni, As, Se, Cd, Sb, Mn, Zn, and Fe exhibited high variability (CV > 0.20), whereas V, Tl, and Co demonstrated stable concentrations (CV < 0.20). Concentrations were found to exceed background values of the upper continental crust of eastern China (UCC), Yangtze River sediments (YZ), and Dongting Lake sediments (DT), particularly at the Xiangjiang estuary (XE) and in the northeastern regions. Speciation analysis revealed that V, Cr, Cu, Ni, and As were predominantly found in the residual fraction (F4), while Pb and Co were concentrated in the oxidizable fraction (F3), Mn and Zn appeared primarily in the exchangeable fractions (F1 and F2), and Cd was notably dominant in the exchangeable fraction (F1), suggesting a high potential for mobility. Additionally, DGT results confirmed a significant potential for the release of Pb, Zn, and Cd. Contamination assessment using the Pollution Load Index (PLI) and Geoaccumulation Index (Igeo) identified Pb, Bi, Ni, As, Se, Cd, and Sb as major pollutants. Among these, Bi and Cd were found to pose the highest risks. Furthermore, the Risk Assessment Code (RAC) and the Potential Ecological Risk Index (PERI) highlighted Cd as the primary ecological risk contributor, especially in the XE. The study identified sediment grain size, pH, electrical conductivity, and nutrient levels as the primary influencing factors. The PMF modeling revealed HM sources as mixed smelting/natural inputs, agricultural activities, natural weathering, and mining/smelting operations, suggesting that remediation should prioritize Cd control in the XE with emphasis on external inputs. Full article
(This article belongs to the Section Water Quality and Contamination)
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23 pages, 7234 KiB  
Article
Cold Exposure Exacerbates Cardiac Dysfunction in a Model of Heart Failure with Preserved Ejection Fraction in Male and Female C57Bl/6J Mice
by Sara-Ève Thibodeau, Marie-Lune Legros, Emylie-Ann Labbé, Élisabeth Walsh-Wilkinson, Audrey Morin-Grandmont, Sarra Beji, Marie Arsenault, Alexandre Caron and Jacques Couet
Biomedicines 2025, 13(8), 1900; https://doi.org/10.3390/biomedicines13081900 - 4 Aug 2025
Abstract
Background: Standard room temperature housing (~22 °C) represents a stress for laboratory mice, resulting in an increased metabolic rate, calorie consumption, heart rate, and catecholamine levels compared to thermoneutral conditions (29–32 °C). Using a recently established two-hit model of heart failure with [...] Read more.
Background: Standard room temperature housing (~22 °C) represents a stress for laboratory mice, resulting in an increased metabolic rate, calorie consumption, heart rate, and catecholamine levels compared to thermoneutral conditions (29–32 °C). Using a recently established two-hit model of heart failure with preserved ejection fraction (HFpEF) (Angiotensin II + High-fat diet for 28 days; MHS), we investigated how housing temperature modulates cardiac remodelling and function in male and female C57Bl/6J mice. Methods: Using the MHS mouse model, we investigated cardiac remodelling and function in 8-week-old C57BL/6J mice of both sexes housed at 10 °C, 22 °C, and 30 °C for four weeks. Control mice were analyzed in parallel. Before the MHS, the animals were allowed to acclimate for a week before the MHS started. Results: Mice housed at 10 °C consumed more food and had increased fat mass compared to those at 22 °C or 30 °C. This was accompanied by increased heart weight, stroke volume, heart rate, and cardiac output. Mice housed at 22 °C and 30 °C were similar for these cardiac parameters. Following MHS, mice at 10 °C and 22 °C developed marked cardiac hypertrophy, whereas thermoneutral housing attenuated this response and reduced left atrial enlargement. Cold-exposed females showed more diastolic dysfunction after MHS (increased E’ wave, E/E’, and isovolumetric relaxation time) than those at 22 °C or 30 °C. Ejection fraction and cardiac output declined significantly at 10 °C after MHS but were preserved at 22 °C and 30 °C in females. Conclusions: Cold housing exacerbates cardiac dysfunction in mice subjected to HFpEF-inducing stress, with pronounced effects in females. In contrast, thermoneutrality limits the cardiac hypertrophic response. Full article
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14 pages, 1282 KiB  
Systematic Review
Actinic Cheilitis: A Systematic Review and Meta-Analysis of Interventions, Treatment Outcomes, and Adverse Events
by Matthäus Al-Fartwsi, Anne Petzold, Theresa Steeb, Lina Amin Djawher, Anja Wessely, Anett Leppert, Carola Berking and Markus V. Heppt
Biomedicines 2025, 13(8), 1896; https://doi.org/10.3390/biomedicines13081896 - 4 Aug 2025
Abstract
Introduction: Actinic cheilitis (AC) is a common precancerous condition affecting the lips, primarily caused by prolonged ultraviolet radiation exposure. Various treatment options are available. However, the optimal treatment approach remains a subject of debate. Objective: To summarize and compare practice-relevant interventions for AC. [...] Read more.
Introduction: Actinic cheilitis (AC) is a common precancerous condition affecting the lips, primarily caused by prolonged ultraviolet radiation exposure. Various treatment options are available. However, the optimal treatment approach remains a subject of debate. Objective: To summarize and compare practice-relevant interventions for AC. Materials and Methods: A pre-defined protocol was registered in PROSPERO (CRD42021225182). Systematic searches in Medline, Embase, and Central, along with manual trial register searches, identified studies reporting participant clearance rates (PCR) or recurrence rates (PRR). Quality assessment for randomized controlled trials (RCTs) was conducted using the Cochrane Risk of Bias tool 2. Uncontrolled studies were evaluated using the tool developed by the National Heart, Lung, and Blood Institute. The generalized linear mixed model was used to pool proportions for uncontrolled studies. A pairwise meta-analysis for RCTs was applied, using the odds ratio (OR) as the effect estimate and the GRADE approach to evaluate the quality of the evidence. Adverse events were analyzed qualitatively. Results: A comprehensive inclusion of 36 studies facilitated an evaluation of 614 participants for PCR, and 430 patients for PRR. Diclofenac showed the lowest PCR (0.53, 95% confidence interval (CI) [0.41; 0.66]), while CO2 laser showed the highest PCR (0.97, 95% CI [0.90; 0.99]). For PRR, Er:YAG laser showed the highest rates (0.14, 95% CI [0.08; 0.21]), and imiquimod the lowest (0.00, 95% CI [0.00; 0.06]). In a pairwise meta-analysis, the OR indicated a lower recurrence rate for Er:YAG ablative fractional laser (AFL)-primed methyl-aminolevulinate photodynamic therapy (MAL-PDT) (Er:YAG AFL-PDT) compared to methyl-aminolevulinate photodynamic therapy (MAL-PDT) alone (OR = 0.22, 95% CI [0.06; 0.82]). The CO2 laser showed fewer local side effects than the Er:YAG laser, while PDTs caused more skin reactions. Due to qualitative data, comparability was limited, highlighting the need for individualized treatment. Conclusions: This study provides a complete and up-to-date evidence synthesis of practice-relevant interventions for AC, identifying the CO2 laser as the most effective treatment and regarding PCR and imiquimod as most effective concerning PRR. Full article
(This article belongs to the Special Issue Skin Diseases and Cell Therapy)
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20 pages, 7843 KiB  
Article
Effect of Ageing on a Novel Cobalt-Free Precipitation-Hardenable Martensitic Alloy Produced by SLM: Mechanical, Tribological and Corrosion Behaviour
by Inés Pérez-Gonzalo, Florentino Alvarez-Antolin, Alejandro González-Pociño and Luis Borja Peral-Martinez
J. Manuf. Mater. Process. 2025, 9(8), 261; https://doi.org/10.3390/jmmp9080261 - 4 Aug 2025
Abstract
This study investigates the mechanical, tribological, and electrochemical behaviour of a novel precipitation-hardenable martensitic alloy produced by selective laser melting (SLM). The alloy was specifically engineered with an optimised composition, free from cobalt and molybdenum, and featuring reduced nickel content (7 wt.%) and [...] Read more.
This study investigates the mechanical, tribological, and electrochemical behaviour of a novel precipitation-hardenable martensitic alloy produced by selective laser melting (SLM). The alloy was specifically engineered with an optimised composition, free from cobalt and molybdenum, and featuring reduced nickel content (7 wt.%) and 8 wt.% chromium. It has been developed as a cost-effective and sustainable alternative to conventional maraging steels, while maintaining high mechanical strength and a refined microstructure tailored to the steep thermal gradients inherent to the SLM process. Several ageing heat treatments were assessed to evaluate their influence on microstructure, hardness, tensile strength, retained austenite content, dislocation density, as well as wear behaviour (pin-on-disc test) and corrosion resistance (polarisation curves in 3.5%NaCl). The results indicate that ageing at 540 °C for 2 h offers an optimal combination of hardness (550–560 HV), tensile strength (~1700 MPa), microstructural stability, and wear resistance, with a 90% improvement compared to the as-built condition. In contrast, ageing at 600 °C for 1 h enhances ductility and corrosion resistance (Rp = 462.2 kΩ; Ecorr = –111.8 mV), at the expense of a higher fraction of reverted austenite (~34%) and reduced hardness (450 HV). This study demonstrates that the mechanical, surface, and electrochemical performance of this novel SLM-produced alloy can be effectively tailored through controlled thermal treatments, offering promising opportunities for demanding applications requiring a customised balance of strength, durability, and corrosion behaviour. Full article
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19 pages, 1769 KiB  
Article
Dynamics of a Fractional-Order Within-Host Virus Model with Adaptive Immune Responses and Two Routes of Infection
by Taofeek O. Alade, Furaha M. Chuma, Muhammad Javed, Samson Olaniyi, Adekunle O. Sangotola and Gideon K. Gogovi
Math. Comput. Appl. 2025, 30(4), 80; https://doi.org/10.3390/mca30040080 (registering DOI) - 2 Aug 2025
Viewed by 96
Abstract
This paper introduces a novel fractional-order model using the Caputo derivative operator to investigate the virus dynamics of adaptive immune responses. Two infection routes, namely cell-to-cell and virus-to-cell transmissions, are incorporated into the dynamics. Our research establishes the existence and uniqueness of positive [...] Read more.
This paper introduces a novel fractional-order model using the Caputo derivative operator to investigate the virus dynamics of adaptive immune responses. Two infection routes, namely cell-to-cell and virus-to-cell transmissions, are incorporated into the dynamics. Our research establishes the existence and uniqueness of positive and bounded solutions through the application of the generalized mean-value theorem and Banach fixed-point theory methods. The fractional-order model is shown to be Ulam–Hyers stable, ensuring the model’s resilience to small errors. By employing the normalized forward sensitivity method, we identify critical parameters that profoundly influence the transmission dynamics of the fractional-order virus model. Additionally, the framework of optimal control theory is used to explore the characterization of optimal adaptive immune responses, encompassing antibodies and cytotoxic T lymphocytes (CTL). To assess the influence of memory effects, we utilize the generalized forward–backward sweep technique to simulate the fractional-order virus dynamics. This study contributes to the existing body of knowledge by providing insights into how the interaction between virus-to-cell and cell-to-cell dynamics within the host is affected by memory effects in the presence of optimal control, reinforcing the invaluable synergy between fractional calculus and optimal control theory in modeling within-host virus dynamics, and paving the way for potential control strategies rooted in adaptive immunity and fractional-order modeling. Full article
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17 pages, 1567 KiB  
Article
Gastrointestinal Digestion Impact on Phenolics and Bioactivity of Tannat Grape Pomace Biscuits
by Victoria Olt, Jessica Báez, Romina Curbelo, Eduardo Boido, Eduardo Dellacassa, Alejandra Medrano and Adriana Maite Fernández-Fernández
Molecules 2025, 30(15), 3247; https://doi.org/10.3390/molecules30153247 - 2 Aug 2025
Viewed by 159
Abstract
The search for natural sources of bioactive compounds with health-promoting properties has intensified in recent years. Among these, Tannat grape pomace (TGP), a primary byproduct of winemaking, stands out for its high phenolic content, although its bioactivity may be affected during gastrointestinal digestion. [...] Read more.
The search for natural sources of bioactive compounds with health-promoting properties has intensified in recent years. Among these, Tannat grape pomace (TGP), a primary byproduct of winemaking, stands out for its high phenolic content, although its bioactivity may be affected during gastrointestinal digestion. This study aimed to evaluate the impact of in vitro digestion on the antioxidant (ABTS, ORAC-FL, intracellular ROS inhibition), anti-diabetic (α-glucosidase inhibition), anti-obesity (lipase inhibition), and anti-inflammatory (NO inhibition) properties of five sugar-free biscuits formulated with varying percentages of TGP and sucralose. No significant differences were observed in the bioaccessible fractions (BFs, representing the compounds potentially released in the small intestine) between control biscuits and those enriched with TGP, suggesting limited release of phenolics at this stage. Conversely, the colonic fractions (CFs, simulating the material reaching the colon) from biscuits with higher TGP content exhibited greater bioactivities. HPLC-DAD-MS analysis of the CF from the biscuit containing 20% TGP and 4% sucralose revealed a high content of procyanidin trimers, indicating the persistence of these specific phenolic compounds after in vitro digestion. These findings suggest that TGP-enriched biscuits may deliver health benefits at the colonic level and support their potential application in the formulation of functional foods. Further microbiota and in vivo studies should be assessed to confirm the latter. Full article
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21 pages, 7537 KiB  
Article
Variable Step-Size FxLMS Algorithm Based on Cooperative Coupling of Double Nonlinear Functions
by Jialong Wang, Jian Liao, Lin He, Xiaopeng Tan and Zongbin Chen
Symmetry 2025, 17(8), 1222; https://doi.org/10.3390/sym17081222 - 2 Aug 2025
Viewed by 181
Abstract
Based on the principle of symmetry, we propose a variable step-size FxLMS algorithm with double nonlinear functions cooperative coupling (DNVSS-FxLMS), aiming to optimize the contradiction between convergence rate and steady-state error in the active pressure pulsation control system of hydraulic systems. The algorithm [...] Read more.
Based on the principle of symmetry, we propose a variable step-size FxLMS algorithm with double nonlinear functions cooperative coupling (DNVSS-FxLMS), aiming to optimize the contradiction between convergence rate and steady-state error in the active pressure pulsation control system of hydraulic systems. The algorithm innovatively couples two types of nonlinear mechanisms (rational-fractional and exponential-function-based), constructing a refined error-step mapping relationship to achieve a balance between rapid convergence and low steady-state error. Simulation experiments were conducted considering the complex time-varying operating environment of a simulation-based hydraulic system. The results demonstrate that, when the system undergoes unstable random changes, the DNVSS-FxLMS algorithm converges at least twice as fast as traditional and existing variable step size algorithms, while reducing steady-state error by 2–5 dB. The proposed DNVSS-FxLMS algorithm exhibits significant advantages in convergence rate, steady-state error reduction, and tracking capability, providing a highly efficient and robust solution for real-time active control of hydraulic system pressure pulsation under complex operating conditions. Full article
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25 pages, 15257 KiB  
Article
A Novel Enhanced Methodology for Position and Orientation Control of the I-SUPPORT Robot
by Carlos Relaño, Zhiqiang Tang, Cecilia Laschi and Concepción A. Monje
Biomimetics 2025, 10(8), 502; https://doi.org/10.3390/biomimetics10080502 - 1 Aug 2025
Viewed by 147
Abstract
This study presents a novel method for controlling the position and orientation of the bioinspired I-SUPPORT soft robot, which represents a relevant advancement in the field of soft robotics. The approach is based on module actuation decoupling and fractional-order control, offering a more [...] Read more.
This study presents a novel method for controlling the position and orientation of the bioinspired I-SUPPORT soft robot, which represents a relevant advancement in the field of soft robotics. The approach is based on module actuation decoupling and fractional-order control, offering a more advanced and robust control solution. This innovation enhances the versatility of the robot and illustrates the efficacy of fractional-order controllers, which are comparable to current meta-learning-based controllers. The research involves experiments in both vertical and horizontal configurations, addressing tasks ranging from simple orientation to complex interactions, such as gentle rubbing during bathing activities with the robot. These experimental results exemplify the efficacy of the proposed control strategy and provide a foundation for future research in soft robotics control, underscoring its potential for broader applications and further technological advancement. Full article
(This article belongs to the Special Issue Design, Actuation, and Fabrication of Bio-Inspired Soft Robotics)
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12 pages, 2015 KiB  
Article
Risk Factors for Radiation-Induced Keratoconjunctivitis Sicca in Dogs Treated with Hypofractionated Intensity-Modulated Radiation Therapy for Intranasal Tumors
by Akihiro Ohnishi, Soichirou Takeda, Yoshiki Okada, Manami Tokoro, Saki Kageyama, Yoshiki Itoh and Taketoshi Asanuma
Animals 2025, 15(15), 2258; https://doi.org/10.3390/ani15152258 - 1 Aug 2025
Viewed by 100
Abstract
Radiation-induced keratoconjunctivitis sicca (KCS) is a significant late complication in dogs receiving radiation therapy for intranasal tumors, particularly with hypofractionated intensity-modulated radiation therapy (IMRT). This retrospective case-control study was performed to identify anatomical and dosimetric risk factors for KCS in 15 canine patients [...] Read more.
Radiation-induced keratoconjunctivitis sicca (KCS) is a significant late complication in dogs receiving radiation therapy for intranasal tumors, particularly with hypofractionated intensity-modulated radiation therapy (IMRT). This retrospective case-control study was performed to identify anatomical and dosimetric risk factors for KCS in 15 canine patients treated with IMRT delivered in 4–6 weekly fractions of 8 Gy. Orbital structures were retrospectively contoured, and dose–volume metrics (D50) were calculated. Receiver operating characteristic (ROC) curve analysis and odds ratios were used to evaluate the associations between radiation dose and KCS development. Six dogs (33%) developed KCS within three months post-treatment. Statistically significant dose differences were observed between affected and unaffected eyes for the eyeball, cornea, and retina. ROC analyses identified dose thresholds predictive of KCS: 13.8 Gy (eyeball), 14.9 Gy (cornea), and 17.0 Gy (retina), with the retina showing the highest odds ratio (28.33). To ensure clinical relevance, KCS was diagnosed based on decreased tear production combined with corneal damage to ensure clinical relevance. This study proposes dose thresholds for ocular structures that may guide treatment planning and reduce the risk of KCS in canine patients undergoing IMRT. Further prospective studies are warranted to validate these thresholds and explore mitigation strategies for high-risk cases. Full article
(This article belongs to the Special Issue Imaging Techniques and Radiation Therapy in Veterinary Medicine)
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32 pages, 15216 KiB  
Article
Leveraging Soil Geography for Land Use Planning: Assessing and Mapping Soil Ecosystem Services Indicators in Emilia-Romagna, NE Italy
by Fabrizio Ungaro, Paola Tarocco and Costanza Calzolari
Geographies 2025, 5(3), 39; https://doi.org/10.3390/geographies5030039 - 1 Aug 2025
Viewed by 115
Abstract
An indicator-based approach was implemented to assess the contributions of soils in supplying ecosystem services, providing a scalable tool for modeling the spatial heterogeneity of soil functions at regional and local scales. The method consisted of (i) the definition of soil-based ecosystem services [...] Read more.
An indicator-based approach was implemented to assess the contributions of soils in supplying ecosystem services, providing a scalable tool for modeling the spatial heterogeneity of soil functions at regional and local scales. The method consisted of (i) the definition of soil-based ecosystem services (SESs), using available point data and thematic maps; (ii) the definition of appropriate SES indicators; (iii) the assessment and mapping of potential SESs provision for the Emilia-Romagna region (22.510 km2) in NE Italy. Depending on data availability and on the role played by terrain features and soil geography and its complexity, maps of basic soil characteristics (textural fractions, organic C content, and pH) covering the entire regional territory were produced at a 1 ha resolution using digital soil mapping techniques and geostatistical simulations to explicitly consider spatial variability. Soil physical properties such as bulk density, porosity, and hydraulic conductivity at saturation were derived using pedotransfer functions calibrated using local data and integrated with supplementary information such as land capability and remote sensing indices to derive the inputs for SES assessment. Eight SESs were mapped at 1:50,000 reference scale: buffering capacity, carbon sequestration, erosion control, food provision, biomass provision, water regulation, water storage, and habitat for soil biodiversity. The results are discussed and compared for the different pedolandscapes, identifying clear spatial patterns of soil functions and potential SES supply. Full article
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22 pages, 7609 KiB  
Article
Bidirectional Conservative–Dissipative Transitions in a Five-Dimensional Fractional Chaotic System
by Yiming Wang, Fengjiao Gao and Mingqing Zhu
Mathematics 2025, 13(15), 2477; https://doi.org/10.3390/math13152477 - 1 Aug 2025
Viewed by 191
Abstract
This study investigates a modified five-dimensional chaotic system by incorporating structural term adjustments and Caputo fractional-order differential operators. The modified system exhibits significantly enriched dynamic behaviors, including offset boosting, phase trajectory rotation, phase trajectory reversal, and contraction phenomena. Additionally, the system exhibits bidirectional [...] Read more.
This study investigates a modified five-dimensional chaotic system by incorporating structural term adjustments and Caputo fractional-order differential operators. The modified system exhibits significantly enriched dynamic behaviors, including offset boosting, phase trajectory rotation, phase trajectory reversal, and contraction phenomena. Additionally, the system exhibits bidirectional transitions—conservative-to-dissipative transitions governed by initial conditions and dissipative-to-conservative transitions controlled by fractional order variations—along with a unique chaotic-to-quasiperiodic transition observed exclusively at low fractional orders. To validate the system’s physical realizability, a signal processing platform based on Digital Signal Processing (DSP) is implemented. Experimental measurements closely align with numerical simulations, confirming the system’s feasibility for practical applications. Full article
(This article belongs to the Special Issue Nonlinear Dynamics and Chaos Theory, 2nd Edition)
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18 pages, 2280 KiB  
Article
Theoretical Modeling of a Bionic Arm with Elastomer Fiber as Artificial Muscle Controlled by Periodic Illumination
by Changshen Du, Shuhong Dai and Qinglin Sun
Polymers 2025, 17(15), 2122; https://doi.org/10.3390/polym17152122 - 31 Jul 2025
Viewed by 211
Abstract
Liquid crystal elastomers (LCEs) have shown great potential in the field of soft robotics due to their unique actuation capabilities. Despite the growing number of experimental studies in the soft robotics field, theoretical research remains limited. In this paper, a dynamic model of [...] Read more.
Liquid crystal elastomers (LCEs) have shown great potential in the field of soft robotics due to their unique actuation capabilities. Despite the growing number of experimental studies in the soft robotics field, theoretical research remains limited. In this paper, a dynamic model of a bionic arm using an LCE fiber as artificial muscle is established, which exhibits periodic oscillation controlled by periodic illumination. Based on the assumption of linear damping and angular momentum theorem, the dynamics equation of the model oscillation is derived. Then, based on the assumption of linear elasticity model, the periodic spring force of the fiber is given. Subsequently, the evolution equations for the cis number fraction within the fiber are developed, and consequently, the analytical solution for the light-excited strain is derived. Following that, the dynamics equation is numerically solved, and the mechanism of the controllable oscillation is elucidated. Numerical calculations show that the stable oscillation period of the bionic arm depends on the illumination period. When the illumination period aligns with the natural period of the bionic arm, the resonance is formed and the amplitude is the largest. Additionally, the effects of various parameters on forced oscillation are analyzed. The results of numerical studies on the bionic arm can provide theoretical support for the design of micro-machines, bionic devices, soft robots, biomedical devices, and energy harvesters. Full article
(This article belongs to the Section Polymer Physics and Theory)
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27 pages, 1628 KiB  
Article
Reliability Evaluation and Optimization of System with Fractional-Order Damping and Negative Stiffness Device
by Mingzhi Lin, Wei Li, Dongmei Huang and Natasa Trisovic
Fractal Fract. 2025, 9(8), 504; https://doi.org/10.3390/fractalfract9080504 - 31 Jul 2025
Viewed by 182
Abstract
Research on reliability control for enhancing power systems under random loads holds significant and undeniable importance in maintaining system stability, performance, and safety. The primary challenge lies in determining the reliability index while optimizing system parameters. To effectively address this challenge, we developed [...] Read more.
Research on reliability control for enhancing power systems under random loads holds significant and undeniable importance in maintaining system stability, performance, and safety. The primary challenge lies in determining the reliability index while optimizing system parameters. To effectively address this challenge, we developed a novel intelligent algorithm and conducted an optimal reliability assessment for a Negative Stiffness Device (NSD) seismic isolation structure incorporating fractional-order damping. This algorithm combines the Gaussian Radial Basis Function Neural Network (GRBFNN) with the Particle Swarm Optimization (PSO) algorithm. It takes the reliability function with unknown parameters as the objective function, while using the Backward Kolmogorov (BK) equation, which governs the reliability function and is accompanied by boundary and initial conditions, as the constraint condition. During the operation of this algorithm, the neural network is employed to solve the BK equation, thereby deriving the fitness function in each iteration of the PSO algorithm. Then the PSO algorithm is utilized to obtain the optimal parameters. The unique advantage of this algorithm is its ability to simultaneously achieve the optimization of implicit objectives and the solution of time-dependent BK equations.To evaluate the performance of the proposed algorithm, this study compared it with the algorithm combines the GRBFNN with Genetic Algorithm (GA-GRBFNN)across multiple dimensions, including performance and operational efficiency. The effectiveness of the proposed algorithm has been validated through numerical comparisons and Monte Carlo simulations. The control strategy presented in this paper provides a solid theoretical foundation for improving the reliability performance of mechanical engineering systems and demonstrates significant potential for practical applications. Full article
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18 pages, 1643 KiB  
Article
Precise Tracking Control of Unmanned Surface Vehicles for Maritime Sports Course Teaching Assistance
by Wanting Tan, Lei Liu and Jiabao Zhou
J. Mar. Sci. Eng. 2025, 13(8), 1482; https://doi.org/10.3390/jmse13081482 - 31 Jul 2025
Viewed by 149
Abstract
With the rapid advancement of maritime sports, the integration of auxiliary unmanned surface vehicles (USVs) has emerged as a promising solution to enhance the efficiency and safety of maritime education, particularly in tasks such as buoy deployment and escort operations. This paper presents [...] Read more.
With the rapid advancement of maritime sports, the integration of auxiliary unmanned surface vehicles (USVs) has emerged as a promising solution to enhance the efficiency and safety of maritime education, particularly in tasks such as buoy deployment and escort operations. This paper presents a novel high-precision trajectory tracking control algorithm designed to ensure stable navigation of the USVs along predefined competition boundaries, thereby facilitating the reliable execution of buoy placement and escort missions. First, the paper proposes an improved adaptive fractional-order nonsingular fast terminal sliding mode control (AFONFTSMC) algorithm to achieve precise trajectory tracking of the reference path. To address the challenges posed by unknown environmental disturbances and unmodeled dynamics in marine environments, a nonlinear lumped disturbance observer (NLDO) with exponential convergence properties is proposed, ensuring robust and continuous navigation performance. Additionally, an artificial potential field (APF) method is integrated to dynamically mitigate collision risks from both static and dynamic obstacles during trajectory tracking. The efficacy and practical applicability of the proposed control framework are rigorously validated through comprehensive numerical simulations. Experimental results demonstrate that the developed algorithm achieves superior trajectory tracking accuracy under complex sea conditions, thereby offering a reliable and efficient solution for maritime sports education and related applications. Full article
(This article belongs to the Section Ocean Engineering)
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