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This book consists of the nine sections: i) the first three sections are related to polymeric electrolyte composites; ii) the next two sections relate to gas diffusion layers (GDLs); iii) the next two sections relate to membrane¬–electrode assembly (MEA); iv) and the final two sections deal with the numerical simulation of flow fields for polymer electrolyte fuel cells (PEFCs). All sections describe recent results of the study of the main components of PEFC stacks. The studies provide the underlying material, electrochemical, and/or mechanical aspects that enhance the mass transport of gas, ions (liquid), and electrons for a better performance of PEFCs and the electrochemical reactions at the triple-phase boundary in electrodes. Each study offers the fundamentals, a comprehensive background, and cutting-edge technology on the aforementioned materials and mass transport phenomena. Related Books Proton Exchange Membrane Fuel Cells (PEMFCs) Engineering Advanced Materials and Technologies

The present reprint contains the collection of articles accepted and published in the Special Issue “Mathematical Modeling and Simulation in Mechanics and Dynamic Systems, 3rd Edition” of the MDPI journal Mathematics. The articles cover a broad range of topics in applied mathematics, mechanics, and dynamic systems, including mathematical modeling of physical systems, computational simulations, nonlinear dynamics, control theory, numerical methods, and engineering applications. These contributions illustrate most recent advances in both theoretical and practical aspects of modeling and simulation, highlighting methods for analyzing and solving complex dynamic problems in mechanics and related fields. The reprint provides for researchers, engineers, and students a comprehensive reference to the latest techniques and applications in mathematical modeling and simulation. This volume is both very valuable for academics and practitioners interested in the theory, methods, and applications of modeling and simulation in mechanical and dynamic systems.

This Special Issue, titled “RF, Microwave, and Millimeter Wave Devices and Circuits and Their Applications”, presents a comprehensive overview of recent innovations in the design of high-frequency systems and of their multidisciplinary applications. The selected contributions span a wide array of domains—from power amplifiers, mixers, and phase shifters to advanced antenna arrays and metamaterial-inspired filters—demonstrating how the latest breakthroughs in circuit topology, device architecture, and packaging techniques are enabling the creation of high-performance systems at frequencies ranging from only a few to tens of gigahertz. We hope that this Special Issue will serve as both a valuable reference and a source of inspiration for engineers, researchers, and industry practitioners working at the frontier of RF, microwave, and millimeter wave technologies.

This Reprint is concerned with the problems of earthquake (EQ) precursors, short-term EQ prediction, and related fundamental scientific physics. EQ prediction (especially short-term prediction) is one of the most challenging subjects in the field of geosciences, and in the last few decades, researchers have achieved a lot of significant progress in various EQ precursors found not only in the lithosphere but also in the atmosphere and ionosphere. Further, the uppermost layer of ionosphere is found to be very sensitive to pre-EQ lithospheric activity, according to data from subionospheric VLF/LF propagation, ionosonde, and TEC observations, as well as satellite in situ observations, leading to the generation of a new intrinsic concept of lithosphere–atmosphere–ionosphere coupling (LAIC). Several hypotheses have already been proposed to explain the LAIC process by making full use of satellite- and ground-based multi-parameter observations, but we are still far from having a complete understanding, and this topic needs further extensive investigation. This Reprint offers new contributions to the LAIC process by presenting 12 papers, most of which deal with the latest findings and achievements related to the study of the LAIC process based on multi-parameter and multi-layer observations, and one of them recommends the use of artificial intelligence in the identification of EQ precursors. We hope that this Reprint will provide you with a new direction for short-term EQ prediction studies and encourage the production of further extensive seismo-electromagnetic studies in the future.

The study of innovative and sustainable technologies for the recovery and reuse of raw materials (RMs) from primary and secondary resources is fundamental for economic and industrial development, in compliance with environmental protection and in the context of a circular economy. Bio/hydrometallurgy consists of leaching and recovery unit operations. Leaching is the solubilization of metals from a solid phase using chemicals or biological agents, whereas recovery is the extraction of metals from polymetallic leachate using physicochemical processes, electrowinning or biological processes. Bio/hydrometallurgical processes are new solutions and represent environmentally sustainable practices, not only in the mining and environmental sectors for the extraction of base, precious and toxic metals and rare earth elements (REE), but also for secondary resource valorization with a high content of critical raw materials (CRMs), which are fundamental in modern technological applications. The e

To enhance the international dissemination of ideas on how to make renewable energy sources a driver of sustainable development for the coming decades, it is necessary to unite the efforts of researchers in the fields of traditional and modern energy, waste-free production, and ecology in multidisciplinary discussions of urgent problems of transition to the use of renewable energy.In order to gain new ideas and insights into these areas worldwide, this book, entitled “Sustainable Development Processes for Renewable Energy Technology”, has been prepared. This book mainly covers original research integrating the principles of sustainable development, the production and recycling of new materials, and the use of renewable energy, reflecting the intended breadth of understanding of the complex interdisciplinary issues that the field of Sustainable Development Processes for Renewable Energy Technology presents. Related Books Energy Development for Sustainability Engineering Sustainable E

Horticultural research has been undergoing fundamental changes to improve crop plants as a result of the emergence of new biochemical and molecular techniques. In addition, integration of new technologies with the desire to develop more sustainable production systems has also spurred production level research. The highlighted Feature Papers here reflect the diversity of the types of research performed on horticultural plant species, spanning basic to applied studies, production systems, and postharvest studies, in addition to highlighting some critical issues facing horticultural plant species. Related Books Feature Papers in Horticulturae Biology & Life Sciences Progress in Horticultural Crops - from Genotype to Phenotype Biology & Life Sciences Genomic Analyses and New Breeding Technologies for the Enhancement of Horticultural Plants Biology & Life Sciences Advances in Research for Horticultural Crops Breeding and Genetics Biology & Life Sciences The State-of-the-Art Propagation a

Although cancer development and progression depend on stochastic mutational events, the tumor has to be seen in the context of the host environment, and unraveling the environmental factors that support solid tumors is at the root of cancer prevention and cure.  This Special Issue, focused on the dynamic crosstalk that occurs between tumor cells and the surrounding microenvironment and also including the cancer cells that represent a reservoir of self-sustaining cells for tumor maintenance, adds new knowledge about tumor–host interactions that is useful for novel diagnostic and therapeutic approaches. Related Books The Shaping of Cancer by the Tumour Microenvironment and Its Relevance for Cancer Therapy Medicine & Pharmacology Molecular Mechanisms of Cancer Development and Metastasis Biology & Life Sciences Angiogenesis in Cancers Biology & Life Sciences ... The Tumor Microenvironment of High Grade Serous Ovarian Cancer Biology & Life Sciences Immunotherapy, Tumor Microenvironment and

Tourism is increasingly tied to broader urban, regional, and rural change, as destinations seek to renew place image, diversify economies, and meet evolving visitor demand. In this process, cultural heritage becomes an active resource rather than a passive asset. Heritage-based tourism can enhance competitiveness, strengthen local narratives, and foster community pride and cohesion. However, tourism-led regeneration may also create tensions when upgrades or visitor priorities overshadow resident needs. Whether outcomes such as resilience, renewal, and improved quality of life are achieved depends largely on governance and whose interests guide development. Sustainable development must therefore include cultural sustainability, not only economic performance. A holistic approach requires attention to how heritage is preserved, interpreted, and adapted across scales. When managed inclusively, tourism can reinforce identity, community empowerment, and well-being while keeping heritage relevant. Overall, tourism, cultural heritage, and sustainable development are closely interconnected. Sustainable tourism depends not just on attracting visitors, but on how places interpret heritage, engage communities, and balance continuity with change to support resilient and meaningful place development.

Within the evolving field of plant–insect interactions, pest management and plant pollination receive a lot of attention because of their implications in crop yield. Host–plant resistance and biological control are important parts aspects of pest management that can bring alternatives to the problems that can arise with insecticide use. This Special Issue presents a collection of papers on the interactions of insects and mites with plants, while highlighting the importance of pest management and pollination.

Computational Intelligence (CI) is the theory, design, application, and development of biologically and linguistically motivated computational paradigms. CI mainly includes three parts: neural networks, fuzzy systems, and evolutionary computation. CI has been widely used to solve complex problems in various domains, such as image processing, point cloud processing, and classification. Due to the great advantages of CI in dealing with practical application problems, more and more researchers have paid attention to the theoretical research and application of CI in recent years. This reprint reports the latest research on applications of computational intelligence. Many novel and interesting methods are introduced, which provide guiding significance for the further development of computational intelligence.

In recent years, cancer immunotherapy has made remarkable progress, revolutionizing cancer treatment. Our Special Issue "Cancer Immunology" in the journal Cancers showcased cutting-edge research and reviews. Building on that success, this new Special Issue explores recent advancements, technologies, and future prospects in cancer immunology, pre-clinical assessments, and clinical trials. While immune checkpoint inhibitors have been transformative, addressing limited response remains crucial. Strategies to overcome resistance, such as combination therapies and targeted pathways, are discussed in the issue. Chimeric antigen receptor (CAR) T cell therapy is an important area of immunotherapy, with exciting findings for enhancing CAR persistence and efficacy. Conventional treatments and monoclonal antibodies also activate immunological mechanisms, boosting cytotoxic efficacy against specific cancers. Identifying biomarkers associated with treatment response is vital for personalized canc

This Special Issue on “New Trends in Catalysis for Sustainable CO2 Conversion”, released in the Catalysts open access journal, shows new research about the development of catalysts and catalytic routes for CO2 valorization, in addition to the optimization of the reaction conditions for the process. This issue includes ten articles and three reviews about different innovative processes for CO2 conversion.Carbon capture and storage (CCS) is a physical process consisting of the separation the CO2 (emitted by industry and the combustion processes for energy generation) and its transportation to geological storage isolates it from the atmosphere in the long term. However, the most promising routes for CO2 mitigation are those pursuing its catalytic valorization. By applying specific catalysts and suitable operating conditions, CO2 molecules react with other components to form longer chains (i.e., hydrocarbons). Accordingly, effort should be made to catalytically valorize CO2 (alone or co-

This Special Issue contains 12 papers devoted to fluid/structure interaction (FSI) problems. The main feature of the problems is an interface on which consistent boundary conditions for both the liquid and the solid regions are formulated. The presented studies cover a wide range of problems and methods for their solution, including problems of weak, or one-way interaction, in which the effect of interface deformation on the fluid flow can be neglected, as well as problems of the strong interaction, for which the interface change affects both the flow and the structure behaviour. The interest in FSI problems is very great due to their practical importance. Recent developments in engineering have led to advanced formulations of FSI problems. Some of them could not be formulated several years ago. The presented papers demonstrate progress in both numerical algorithms, mathematical apparatus and advanced computational techniques. In this issue, we have tried to collect different FSI pro

Mercury is a toxic global contaminant that is transported through the atmosphere, is deposited in terrestrial and aquatic ecosystems, and concentrates up the food chain, reaching levels that can harm both humans and wildlife. This book reports the latest findings describing the distribution, deposition, and measurement of this airborne pollutant as well as the human and environmental impacts of artisanal mining of mercury and gold. The research originates from around the world and highlights the importance of atmospheric mercury research and the Minamata Convention on Mercury, a global treaty to protect human health and the environment from anthropogenic emissions of mercury. Related Books Atmospheric Mercury Environmental & Earth Sciences Mercury and Methylmercury Contamination of Terrestrial and Aquatic Ecosystems Environmental & Earth Sciences Mercury and Methylmercury Toxicology and Risk Assessment Chemistry & Materials Science Atmospheric Heavy Metal and Nitrogen Deposition Using

The “Digestive Enzymes in Health and Disease” Special Issue Reprint explores the diverse roles of digestive enzymes in physiological processes, their implications in disease mechanisms, and their therapeutic potential in clinical applications. Digestive enzymes are essential to maintaining metabolic homeostasis, aiding in nutrient digestion and absorption, and protecting against gastrointestinal dysfunction. Disruptions in digestive enzyme activity are associated with the development of disorders such as malabsorption syndromes and inflammatory bowel disease and metabolic conditions such as obesity and diabetes. Recent advances in the research field offer novel insights into the functions of these digestive enzymes, many of which include “extra-digestive” roles, paving the way for possible innovative therapeutic strategies. The Special Issue Reprint will thus deepen our understanding of digestive enzymes and their clinical relevance.

Vector-borne and zoonotic diseases in dogs and cats are widely distributed throughout the world; however, their epidemiology and etiology varies depending on the specific climatic conditions, as well as the presence and abundance of vectorial agents. Climatic and ecological changes and globalization are now affecting the distribution and patterns of transmission vectors and, as a consequence, have introduced etiological agents that can potentially affect dogs, cats, and their owners. On the other hand, the patterns of the classical clinical signs of these diseases are changing; thus, their diagnosis may be challenging. This Special Issue is focused on vector-borne agents and diseases affecting dogs and cats with potential zoonosis and aims to disseminate knowledge on the current status of vector-borne diseases all around the world. For the effective control and prevention of these diseases, a thorough knowledge of the infectious agents, their vectors, and major hosts is required in every ecological region at both the national and regional levels.

This Special Issue of Molecules is dedicated to Prof. Austin James Barnes by occasion of his 75th birthday, in acknowledgment of his scientific contributions in the fields of molecular spectroscopy and molecular structure. The Special Issue comprises 12 articles that span a broad range of interests within the fields of molecular spectroscopy and molecular structure, such as hydrogen bonding, intermolecular interactions, chemical reactivity, weakly bound species and applied spectroscopy.Prof. Austin J. Barnes was one of the most influential scientists in his domain of specialization, and his long scientific career has been an example to follow.

This collection of papers presents a systematic and representative vision of the current status of the art on magneto-rheological  fluids (MRFs), including their classical and novel applications. Each topic is presented with a rich and updated bibliography, helping readers to further deepen their knowledge of the matter. This reprint presents international contributions from researchers in many countries in Europe and Asia. The Editors are senior researchers at the Italian Aerospace Research Centre and the University of Naples Federico II in Italy, and at the Polymer Competence Center in Leoben, Austria. Related Books The Advances in Fluid Mechanics Engineering Analysis and Applications of Mathematical Fluid Dynamics Physical Sciences Metallic Functional Materials Chemistry & Materials Science Recent Advances in Smart Materials for Sensor and Actuator Applications Engineering Soft Magnetic Materials and Their Application Chemistry & Materials Science The recommendations have been g

In recent years, researchers have shown a special interest in natural products as alternative methods for the prevention, treatment, and/or management of various skin illnesses and disorders, primarily due to their natural availability, efficacity, reduced cost, and minimal toxicity. In a similar vein, synthetic bioactives, as well as small molecules, have been studied in vitro, in vivo, and in clinical studies as potential drugs or supplements. This Special Issue of Nutrients comprises an array of literature reviews, original communications, and studies on the roles of natural products, synthetic bioactives, and small molecules in a variety of skin disorders and diseases, such as aging, atopic dermatitis, cutaneous T-cell lymphomas, melanoma, allergies, hyperpigmentation, inflammation, and more, which were investigated through in vitro and ex vivo approaches, preclinical trials, cell-based assays, and animal models. The mechanisms of action of certain compounds are proposed, while o

This second Special Issue connects both the fundamental and application aspects of thermomechanical machines and processes. Among them, engines have the largest place (Diesel, Lenoir, Brayton, Stirling), even if their environmental aspects are questionable for the future. Mechanical and chemical processes as well as quantum processes that could be important in the near future are considered from a thermodynamical point of view as well as for applications and their relevance to quantum thermodynamics. New insights are reported regarding more classical approaches: Finite Time Thermodynamics F.T.T.; Finite Speed thermodynamics F.S.T.; Finite Dimensions Optimal Thermodynamics F.D.O.T. The evolution of the research resulting from this second Special Issue ranges from basic cycles to complex systems and the development of various new branches of thermodynamics.

Human well-being and the prerequisite sustainable environmental management are currently at stake, reaching a bottleneck when trying to cope with (i) the ever-growing world population, (ii) the constantly increasing need for natural resources (and the subsequent overexploitation of species, habitats, ecosystems, and landscapes) and (iii) the documented and on-going impacts of climate change. By this, the role of conservation and management practices for the environment is characterized as a crucial and top issue and should deal with (a) promoting best practices from the local to the global level, (b) identifying spatial and temporal knowledge gaps, (c) multidisciplinary aspects for sustainable management practices, (d) identifying and interpreting the role of stakeholders and socio-economic parameters in the decision-making process, and (e) methods and practices to integrate the concept of ecosystem services into natural capital assessment and accounting, conservation and management s

A couple in love, a white dress with veil, a ritual with flowers and a vow: these are some of the images that we link to weddings. But why do we have these ideas regarding weddings? Our imaginations are strongly influenced by different media, such as novels, newspaper articles, films, TV series, images, social media reels, etc. In these media, the ideal wedding is staged, debated and constructed. The actual wedding rituals are as diverse as each cultural–religious context and individual, and underlie complex processes of change, adaptation, tradition and innovation. On a theoretical level, we can link rites of passage with the symbolic transformation of the social status of the individuals—the wedding couple. In the context of the ritual, the everyday world is transcended and socially changed. The basic categories of a society, such as family, gender, status, age, are thereby expressed and formed. This reprint focusses on the interrelations between weddings as rites of passage, their link to religious traditions, their mediatisation and the values as well as norms connected with them. Values and norms in wedding practices are numerous, complex, and interlinked on several levels, notably social, political, cultural, historical, and economic. The papers in this reprint explore this complexity from different perspectives, and the reprint itself presents a dialogue between approaches towards philosophical, historical, sociological and religious studies.

This is a Reprint of one of the first Special Issues of Algorithms ever published. It focuses on the theoretical and practical performance of algorithms for solving computational problems involving graphs. Several highly cited articles are included, which investigate topics such as the maximum clique problem, the Dubins traveling salesman problem, and computing the eccentricity distribution of a graph.