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Tourism villages represent a key breakthrough for achieving rural revitalization and integrated urban–rural development. By analyzing the spatial patterns of tourism villages in the Great Mount Huang district and their influencing factors, this study provides a scientific foundation for the high-quality development of rural tourism and for the enhancement and sustainable management of regional leisure tourism systems. Using methods such as the nearest neighbor index, kernel density, geographic detector, and geographically weighted regression analysis, the results reveal: (1) the spatial distribution of tourism villages in the Great Mount Huang district exhibits significant clustering and unevenness, forming a spatial pattern characterized by “one cluster, two cores, and three points”; Anqing City shows the most concentrated and uneven distribution of tourism villages; (2) the number of Grade A tourist attractions and cultural resources are dominant factors; tourism culture and natural environment are the most influential dimensions affecting the spatial distribution of tourism villages in the Great Mount Huang district; the development of rural tourism requires consideration of multiple aspects and factors, emphasizing multidimensional coordination; (3) the average slope and the number of Grade A tourist attractions exhibit the greatest spatial variability, while the average elevation shows the lowest spatial variability; average elevation, average slope, per capita disposable income, the number of Grade A tourist attractions, and cultural resources all show a positive correlation with the distribution of tourism villages. Full article

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24 pages, 2566 KB

Open AccessReview

Valorization of Second Cheese Whey Through Microalgae-Based Treatments: Advantages, Limits, and Opportunities

by Gloria Sciuto, Nunziatina Russo, Cinzia L. Randazzo and Cinzia Caggia

BioTech 2025, 14(4), 79; https://doi.org/10.3390/biotech14040079 - 9 Oct 2025

Abstract

The dairy sector produces considerable amounts of nutrient-rich effluents, which are frequently undervalued as simple by-products or waste. In particular, Second Cheese Whey (SCW), also known as scotta, exhausted whey, or deproteinized whey, represents the liquid fraction from ricotta cheese production. Despite its abundance and high organic and saline content, SCW is often improperly discharged into terrestrial and aquatic ecosystems, causing both environmental impact and resource waste. The available purification methods are expensive for dairy companies, and, at best, SCW is reused as feed or fertilizer. In recent years, increasing awareness of sustainability and circular economy principles has increased interest in the valorization of SCW. Biological treatment of SCW using microalgae represents an attractive strategy, as it simultaneously reduces the organic load and converts waste into algal biomass. This biomass can be further valorized as a source of proteins, pigments, and bioactive compounds with industrial relevance, supporting applications in food, nutraceuticals, biofuels, and cosmetics. This review, starting from analyzing the characteristics, production volumes, and environmental issues associated with SCW, focused on the potential of microalgae application for their valorization. In addition, the broader regulatory and sustainability aspects related to biomass utilization and treated SCW are considered, highlighting both the promises and limitations of microalgae-based strategies by integrating technological prospects with policy considerations. Full article

(This article belongs to the Special Issue A Sustainable Approach to Macroalgae and Microalgae: From Cultivation to Compound Recovery and Biotechnological Applications)

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102 pages, 1631 KB

Open AccessReview

A Comprehensive Review on the Generalized Sylvester Equation AX − YB = C

by Qing-Wen Wang and Jiale Gao

Symmetry 2025, 17(10), 1686; https://doi.org/10.3390/sym17101686 - 8 Oct 2025

Abstract

Since Roth’s work on the generalized Sylvester equation (GSE)

A X - Y B = C

Since Roth’s work on the generalized Sylvester equation (GSE)

A X - Y B = C

in 1952, related research has consistently attracted significant attention. Building on this, this review systematically summarizes relevant research on GSE from five perspectives: research methods, constrained solutions, various generalizations, iterative algorithms, and applications. Furthermore, we provide comments on current research, put forward several intriguing questions, and offer prospects for future research trends. We hope this work can fill the gap in the review literature on GSE and offer some inspiration for subsequent studies in the field. Full article

(This article belongs to the Special Issue Mathematics: Feature Papers 2025)

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30 pages, 10629 KB

Open AccessArticle

Content-Adaptive Reversible Data Hiding with Multi-Stage Prediction Schemes

by Hsiang-Cheh Huang, Feng-Cheng Chang and Hong-Yi Li

Sensors 2025, 25(19), 6228; https://doi.org/10.3390/s25196228 - 8 Oct 2025

Abstract

With the proliferation of image-capturing and display-enabled IoT devices, ensuring the authenticity and integrity of visual data has become increasingly critical, especially in light of emerging cybersecurity threats and powerful generative AI tools. One of the major challenges in such sensor-based systems is the ability to protect privacy while maintaining data usability. Reversible data hiding has attracted growing attention due to its reversibility and ease of implementation, making it a viable solution for secure image communication in IoT environments. In this paper, we propose reversible data hiding techniques tailored to the content characteristics of images. Our approach leverages subsampling and quadtree partitioning, combined with multi-stage prediction schemes, to generate a predicted image aligned with the original. Secret information is embedded by analyzing the difference histogram between the original and predicted images, and enhanced through multi-round rotation techniques and a multi-level embedding strategy to boost capacity. By employing both subsampling and quadtree decomposition, the embedding strategy dynamically adapts to the inherent characteristics of the input image. Furthermore, we investigate the trade-off between embedding capacity and marked image quality. Experimental results demonstrate improved embedding performance, high visual fidelity, and low implementation complexity, highlighting the method’s suitability for resource-constrained IoT applications. Full article

(This article belongs to the Special Issue Data Security Approaches for Autonomous Systems, IoT, and Smart Sensing Systems)

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17 pages, 9190 KB

Open AccessArticle

Mineralogical and Gemological Characteristics and Color Genesis of Zibai Jade

by Linhui Song, Mingyue He, Ziyun Zhang and Ling Yang

Crystals 2025, 15(10), 871; https://doi.org/10.3390/cryst15100871 - 8 Oct 2025

Abstract

Zibai Jade is a recently identified hydrogrossular-dominant jade originating from Shaanxi Province, China. It constitutes a polymineralic aggregate composed predominantly of hydrogrossular, with minor proportions of vesuvianite, diopside, chlorite, uvarovite, and calcite. A multi-method analytical approach was employed to characterize this jade, incorporating conventional gemological testing, polarizing microscopy, SEM, XRD, BSE, XRF, and EPMA, as well as UV-Vis and infrared (IR). These techniques enabled a detailed examination of its mineralogy, surface features, and color origin. The stone displays a heterogeneous color distribution, featuring a base hue of light green to yellowish-green, accompanied by distinct occurrences of emerald-green spots, dark green spots, mossy green inclusions, white patches, white veinlets, and a black dot with a green ring. Microanalytical results indicate that the emerald-green spots are principally composed of uvarovite; the dark green spots are dominated by hydrogrossular, diopside, and chlorite; fibrous green inclusions consist mainly of chlorite and Cr-bearing grossular; white patches and veinlets are primarily composed of calcite; and the black dot with a green ring predominantly comprises chromite and uvarovite. Coloration is attributed to the combined influence of Fe and Cr³⁺. The formation of Zibai Jade involved three mineralization stages: deposition of a carbonate protolith, high-temperature metasomatism, and retrograde alteration. The metasomatism was driven by hydrothermal fluids derived from granodioritic and ultramafic rocks, which provided Si, Al, and the essential Cr, respectively. The interplay of these processes resulted in the development of Zibai Jade, which exhibits a dense texture and attractive coloration. Full article

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15 pages, 2424 KB

Open AccessArticle

Comparative Study of TriVariant and Delta Three-Degree-of-Freedom Parallel Mechanisms for Aerial Manipulation

by Zhujin Jiang, Yihao Lin, Yueyuan Zhang, Mingxiang Ling and Chao Liu

Machines 2025, 13(10), 926; https://doi.org/10.3390/machines13100926 - 7 Oct 2025

Abstract

The operational performance of robotic arms for multi-rotor flying robots (MFRs) has attracted growing attention in recent years. To explore new possibilities for aerial manipulation, this study investigates a novel parallel mechanism, the TriVariant, comprising one UP limb and two identical UPS limbs (2-UPS&UP). To evaluate its potential, we analyze its dimensional and kinematic characteristics and benchmark them against the widely adopted Delta robot, which is commonly integrated with unmanned aerial vehicles (UAVs). A prototype of the TriVariant is fabricated for experimental validation. Both analytical and experimental results reveal that, within a cylindrical task workspace characterized by a large diameter and moderate height, the TriVariant offers a more compact structure than the Delta robot, despite its slightly reduced dexterity. These findings highlight that the TriVariant is especially suitable for aerial manipulation in space-constrained environments where all limbs must be mounted beneath the UAV. Full article

(This article belongs to the Special Issue Smart UAV Machines for Detection and Classification: Advancements and Applications in Renewable Energy Technologies)

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21 pages, 2923 KB

Open AccessReview

Structure-Based Understanding of Cu²⁺ Coordination in Fluorescent Proteins for Metal Biosensor Applications—A Review

by Ki Hyun Nam

Biosensors 2025, 15(10), 675; https://doi.org/10.3390/bios15100675 - 7 Oct 2025

Abstract

Copper ions play essential roles in biological systems, but they can cause toxicity following dysregulation or excessive accumulation. In addition, environmental overexposure to Cu²⁺ can lead to serious agricultural and ecological issues. Accurate detection of Cu²⁺ is therefore critical in both medical diagnostics and environmental monitoring. Fluorescent proteins (FPs), which are widely used in molecular and cell biology, have been suggested as attractive modalities for metal ion detection owing to their biocompatibility and specific responsiveness to metal ions. The fluorescence emission of FPs is efficiently quenched by Cu²⁺ in a reversible manner, suggesting the potential to develop Cu²⁺-responsive biosensors. To develop highly sensitive and selective Cu²⁺ biosensors based on FPs, an understanding of Cu²⁺ binding to FPs is crucial, along with FP engineering guided by structural analysis. In this study, the molecular properties of FPs and their fluorescence responses to metal ions were reviewed. The crystal structures of FPs complexed with Cu²⁺ were analyzed, revealing both specific and nonspecific Cu²⁺ binding modes. This structural analysis provides insights into the potential of engineering FPs to enhance sensitivity and selectivity for Cu²⁺ detection. Full article

(This article belongs to the Special Issue Fluorescent Probes: Design and Biological Applications)

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21 pages, 5920 KB

Open AccessArticle

Enhanced CO₂ Separation Performance of Mixed Matrix Membranes with Pebax and Amino-Functionalized Carbon Nitride Nanosheets

by Mengran Hua, Qinqin Sun, Na Li, Mingchao Zhu, Yongze Lu, Zhaoxia Hu and Shouwen Chen

Membranes 2025, 15(10), 306; https://doi.org/10.3390/membranes15100306 - 7 Oct 2025

Abstract

Highly permeable and selective membranes are crucial for energy-efficient gas separation. Two-dimensional (2D) graphitic carbon nitride (g-C₃N₄) has attracted significant attention due to its unique structural characteristics, including ultra-thin thickness, inherent surface porosity, and abundant amine groups. However, the interfacial defects caused by poor compatibility between g-C₃N₄ and polymers deteriorate the separation performance of membrane materials. In this study, amino-functionalized g-C₃N₄ nanosheets (CN@PEI) was prepared by a post-synthesis method, then blended with the polymer Pebax to fabricate Pebax/CN@PEI mixed matrix membranes (MMMs). Compared to g-C₃N₄, MMMs with CN@PEI loading of 20 wt% as nanofiller exhibited a CO₂ permeance of 241 Barrer as well as the CO₂/CH₄ and CO₂/N₂ selectivity of 39.7 and 61.2, respectively, at the feed gas pressure of 2 bar, which approaches the 2008 Robeson upper bound and exceeded the 1991 Robeson upper bound. The Pebax/CN@PEI (20) membrane showed robust stability performance over 70 h continuous gas permeability testing, and no significant decline was observed. SEM characterization revealed a uniform dispersion of CN@PEI throughout the Pebax matrix, demonstrating excellent interfacial compatibility between the components. The increased free volume fraction, enhanced solubility, and higher diffusion coefficient demonstrated that the incorporation of CN@PEI nanosheets introduced more CO₂-philic amino groups and disrupted the chain packing of the Pebax matrix, thereby creating additional diffusion channels and facilitating CO₂ transport. Full article

(This article belongs to the Special Issue Novel Membranes for Carbon Capture and Conversion)

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13 pages, 3860 KB

Open AccessArticle

Mechanical Performance and Energy Absorption of Ti6Al4V I-WP Lattice Metamaterials Manufactured via Selective Laser Melting

by Le Yu, Xiong Xiao, Xianyong Zhu, Jiaan Liu, Guangzhi Sun, Yanheng Xu, Song Yang, Cheng Jiang and Dongni Geng

Materials 2025, 18(19), 4626; https://doi.org/10.3390/ma18194626 - 7 Oct 2025

Viewed by 36

Abstract

Metamaterial lattice structures based on a Triply Periodic Minimal Surface (TPMS) structure have attracted much attention due to their excellent mechanical properties and energy absorption capabilities. In this study, a novel TPMS lattice metamaterial structure (IWP-X) is designed to enhance the axial mechanical properties by fusing an X-shaped plate with an IWP surface structure. A selective laser melting (SLM) machine was utilized to print the designed lattice structures with Ti6Al4V powder. The thickness of the plate and the density of the IWP are varied to explore the responsivity of the mechanical and energy absorption properties with the volume ratio of IWP-X. The finite element simulation analysis is used to effectively predict the stress distribution and fracture site of each structure in the compression test. The results show that the IWP-X structure obtains the ultimate compressive strength of 122.06% improvement, and the energy absorption of 282.03% improvement. The specific energy absorption (SEA) reaches its maximum value in the plate-to-IWP volume ratio of 0.7 to 0.8. Full article

(This article belongs to the Special Issue Multiscale Mechanical Behaviors of Advanced Materials and Structures)

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25 pages, 2810 KB

Open AccessReview

Fishways in Portugal: Status, Main Findings and Research Needs

by José M. Santos, Ana L. Quaresma, Filipe Romão, Susana D. Amaral, Daniel Mameri, Marta Santo, Jorge Bochechas, Ana Telhado, Francisco N. Godinho, João Pádua, Paulo J. Pinheiro, Ana T. Silva, Teresa Viseu, Pedro R. Almeida, Teresa Ferreira, António N. Pinheiro and Paulo Branco

Water 2025, 17(19), 2898; https://doi.org/10.3390/w17192898 - 7 Oct 2025

Viewed by 174

Abstract

Anthropogenic barriers fragment Portuguese rivers, threatening endemic freshwater fish communities. This study compiled national inventories and peer-reviewed research (2002–2024) to quantify fishway implementation, evolution and typology, while evaluating fish performance from published research. One hundred fishways built between 1950 and 2024 were recorded, half of which were constructed after the implementation of the Water Framework Directive in Portugal (29 Dec 2005), tripling the annual construction rate. Fishways were found to be associated mainly with weirs (46%) and small hydropower plants (44%), with typology being dominated by the pool-type design (67%), nature-like facilities (18%), fish locks and combined systems (6% each), fish lifts (2%) and a single eel pass. Forty scientific contributions addressed fishway effectiveness; three-quarters dealt with pool-type facilities, while 12.5% and 10% focused on nature-like fishways and lifts, respectively. Experimental and field studies highlighted species-specific hydraulic preferences, the benefits of vertical slot and multislot configurations, and the potential of retrofitting fishways with macro-rugosities (i.e., fixed structural elements placed on the bottom) to improve non-salmonid fish passage. However, low attraction efficiency, limited multi-season monitoring and risks of aiding invasive species remain a concern. Research needs are proposed, including the refinement of species-specific hydrodynamic criteria, and the development of standardized efficiency metrics and of selective passage solutions, to advance fishway performance under Mediterranean hydrological constraints. Full article

(This article belongs to the Section Ecohydrology)

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14 pages, 7266 KB

Open AccessArticle

Investigation of Control Systems of FOPDT Plants with Dynamics Asymmetry

by Algirdas Baskys

Appl. Sci. 2025, 15(19), 10770; https://doi.org/10.3390/app151910770 - 7 Oct 2025

Viewed by 48

Abstract

This work investigates feedback control systems with first order plus dead time (FOPDT) plants, which are characterized by asymmetric dynamics. The term asymmetric dynamics is understood to mean that the dynamics of the response of the controlled parameter of the plant to the rise and fall of the plant control signal are different. The novelty of the current work is that it analyzes a case where the asymmetry is introduced by both dynamic parameters of the FOPDT plant: by the asymmetry of the time constant and by the asymmetry of the response delay. Another novelty is that in the proposed asymmetrical PI (aPI) controller, the change in the plant control signal time derivative sign is used to determine the moments for the switching of controller parameters. The use of an aPI controller instead of a conventional PI controller allows us to improve the quality of the control of plants with asymmetric dynamics. It is also important that the problem is solved using a PI type controller, which automation engineers are well aware of and know how to tune its parameters to the dynamics of the plant. Therefore, an aPI controller can be attractive in practical applications. All investigations were performed using Matlab/Simulink software (version R2021b). Full article

(This article belongs to the Special Issue Enhancing User Experience in Automation and Control Systems)

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23 pages, 1736 KB

Open AccessArticle

Gap Analysis and Development of Low-Carbon Tourism in Chiang Mai Province Towards Sustainable Tourism Goals

by Kanokwan Khiaolek, Det Damrongsak, Wongkot Wongsapai, Korawan Sangkakorn, Walinpich Kumpiw, Tassawan Jaitiang, Ratchapan Karapan, Wasin Wongwilai, Nattasit Srinurak, Janjira Sukwai, Suwipa Champawan and Pongsathorn Dhumtanom

Sustainability 2025, 17(19), 8889; https://doi.org/10.3390/su17198889 - 6 Oct 2025

Viewed by 237

Abstract

This paper aims to conduct a gap analysis and explore the potential for greenhouse gas (GHG) emissions reduction in the tourism sector of Chiang Mai province, with the goal of promoting sustainable tourism. Chiang Mai is a major tourism hub in Thailand, located in the Northern Economic Corridor (NEC). The gap analysis of small- and medium-sized tourism enterprises will be examined across four dimensions: (1) management, (2) socio-economy, (3) cultural, and (4) environmental. In 2024, Chiang Mai’s tourism revenue accounted for 46.97% of the northern region’s total tourism revenue and 3.73% of Thailand’s total tourism revenue. Given this economic significance, the development of sustainable tourism should be accelerated to meet the expectations of new tourists who are increasingly concerned about the environment. To address this need, this study analyzes the gaps in small- and medium-sized tourism enterprises and assesses GHG emissions through interviews and surveys of 90 tourism-related establishments across nine sectors: hotels, restaurants and beverages, tour agencies, transportation, souvenirs, attractions and activities, spas and wellness, community-based tourism, and farm tourism. The total GHG emissions from these establishments were found to be 15,303.72 tCO₂eq. Moreover, if renewable energy from solar power were adopted, an installation capacity of 21,866.84 kWp would be required. Such a transition would not only reduce emissions, but also support low-carbon development in small- and medium-sized tourism enterprises and ultimately contribute to achieving net-zero tourism. Finally, this study contributes to the advancement of STGs 1–17, adapted from the SDGs 1–17, with particular emphasis on SDG 7 on clean energy and SDG 13 on climate change. Full article

(This article belongs to the Special Issue The Role of Small and Medium Enterprises in Realizing the Sustainable Development Goals)

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16 pages, 1854 KB

Open AccessArticle

Electrostatic Targeting of Cancer Cell Membrane Models by NA-CATH:ATRA-1-ATRA-1: A Biophysical Perspective

by Maria C. Klaiss-Luna, Małgorzata Jemioła-Rzemińska, Marcela Manrique-Moreno and Kazimierz Strzałka

Membranes 2025, 15(10), 303; https://doi.org/10.3390/membranes15100303 - 6 Oct 2025

Viewed by 180

Abstract

Breast cancer continues to be the leading cancer diagnosis among women worldwide, affecting populations in both industrialized and developing regions. Given the rising number of diagnosed cases each year, there is an urgent need to explore novel compounds with potential anticancer properties. One group of such candidates includes cationic peptides, which have shown promise due to their unique membrane-targeting mechanisms that are difficult for cancer cells to resist. This study presents an initial biophysical assessment of NA-CATH:ATRA-1-ATRA-1, a synthetic peptide modeled after NA-CATH, originally sourced from the venom of the Chinese cobra (Naja atra). The peptide’s interactions with lipid bilayers mimicking cancerous and healthy cell membranes were examined using differential scanning calorimetry and Fourier-transform infrared spectroscopy. Findings revealed a pronounced affinity of NA-CATH:ATRA-1-ATRA-1 for eukaryotic membrane lipids, particularly phosphatidylserine, indicating that its mechanism likely involves electrostatic attraction to negatively charged lipids characteristic of cancer cell membranes. Such biophysical insights are vital for understanding how membrane-active peptides could be harnessed in future cancer therapies. Full article

(This article belongs to the Collection Feature Papers in Membranes in Life Sciences)

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27 pages, 788 KB

Open AccessArticle

Supply Chain Ecosystem for Smart Sustainable City Multifloor Manufacturing Cluster: Knowledge Management Based on Open Innovation and Energy Conservation Policies

by Tygran Dzhuguryan, Kinga Kijewska, Stanisław Iwan and Karina Dzhuguryan

Sustainability 2025, 17(19), 8882; https://doi.org/10.3390/su17198882 - 6 Oct 2025

Viewed by 136

Abstract

City manufacturing (CM) is a key concept in smart sustainable cities. City multifloor manufacturing clusters (CMFMCs) are an integral part of large urban areas. Although smart sustainable CMFMCs attract growing attention, a major research gap remains. It concerns how different actors drive innovation within their supply chain ecosystems (SCEs). To address this gap, this paper examines the SCE of a CMFMC and knowledge management (KM) mechanisms of open innovation (OI), considering energy conservation (EC) policies. This qualitative study expands the understanding of the spatial configuration and key actors of the SCE of a CMFMC. It also analyses the role of the University Centre for Projects and Innovation (UCPI) as a physical orchestrator. The UCPI fosters innovation activity through KM based on OI and EC. Our findings contribute to the SCE literature by emphasizing the potential of its key actors. We show that an integrated approach to KM based on OI and EC enhances innovation in CMFMCs. This supports the sustainable development of smart cities. Full article

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14 pages, 1596 KB

Open AccessArticle

Clinical Decision-Making in Implant Planning: A Comparison Between Human and Artificial Intelligence

by Fehmi Gönüldaş, Elif Arya Bulut, Özge Nur Özbey and Caner Öztürk

Appl. Sci. 2025, 15(19), 10744; https://doi.org/10.3390/app151910744 - 6 Oct 2025

Viewed by 181

Abstract

Artificial intelligence (AI), particularly large language models (LLMs) such as ChatGPT, has attracted attention for its potential to enhance diagnostic decision-making. This study aims to compare the decision-making tendencies of clinicians from different disciplines regarding implant planning with the approach of ChatGPT and to evaluate the potential integration of AI into clinical decision-making. This cross-sectional, survey-based study compared the implant planning decisions of prosthodontic and surgical residents with those of ChatGPT 4.0 and each other. Fourteen cases were presented to 20 prosthodontics, 20 oral and maxillofacial surgery residents, and ChatGPT. Participants selected the option they found most appropriate; responses were compared case by case using chi-square tests with p < 0.05. The responses of residents showed no statistically significant differences. However, comparisons between the AI and clinicians revealed significant differences in 11 of the scenarios. In clinical scenarios where no differences were found, both human and artificial intelligence tended to make the same choices on less complicated cases. While AI is increasingly advancing in clinical decision-making, its responses to clinical scenarios may show some inconsistencies. AI demonstrated similarity in simple cases but diverged in complex ones. While promising as a support, broader studies with diverse scenarios are necessary to enhance the integration potential of AI in clinical decision-making. Full article

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