Modern Research and Investigations in Natural and Mathematical Sciences III

MODERN RESEARCH AND INVESTIGATIONS IN NATURAL AND MATHEMATICAL SCIENCES III Editor Nurhan GÜMRÜKÇÜOĞLU Lyon 2025 MODERN RESEARCH AND INVESTIGATIONS IN NATURAL AND MATHEMATICAL SCIENCES III Editor Nurhan GÜMRÜKÇÜOĞLU Lyon 2025 Modern Research and Investigations in Natural and Mathematical Sciences III Editor • Prof. Dr. Nurhan GÜMRÜKÇÜOĞLU • Orcid: 0000-0002-9669-6318 Cover Design • Motion Graphics Book Layout • Motion Graphics First Published • October 2025, Lyon e-ISBN: 978-2-38236-916-6 DOI: 10.5281/zenodo.17371230 copyright © 2025 by Livre de Lyon All rights reserved. No part of this publication may be reproduced, stored in a retrieval system, or transmitted in any form or by any means, electronic, mechanical, photocopying, recording, or otherwise, without prior written permission from the Publisher. The author or authors of the relevant section are responsible for any copyright infringement that may occur due to the images and graphics used in the book. The editor or publisher does not assume responsibility in this regard. Publisher • Livre de Lyon Address • 37 rue marietton, 69009, Lyon France website • http://www.livredelyon.com e-mail • [email protected] i FOREWORD The book “Modern Research and Investigations in Natural and Mathematical Sciences–III” brings together recent and interdisciplinary studies conducted by researchers in the fields of natural sciences and mathematics. This volume aims to provide readers with up-to-date information and innovative perspectives on current scientific developments, offering valuable insights for academics, professionals, and students alike. In this edition, researchers from diverse scientific disciplines present their latest findings, contributing to the expansion of knowledge and the exchange of ideas within the scientific community. Each chapter reflects rigorous academic work, innovative methodology, and a strong commitment to scientific advancement. All chapters included in this volume have been carefully reviewed and selected by expert referees to ensure academic quality and relevance. The authors have generously shared their research without expecting any return, for which we express our deepest gratitude. We also extend our special thanks to our reviewers for their dedicated and meticulous efforts that made the publication of this book possible, and to Livre de Lyon Publishing House for their continuous support and professional collaboration throughout the publication process. We hope that this volume will inspire further research, foster scientific collaboration, and serve as a valuable reference for those interested in the latest developments in natural and mathematical sciences. Editor Prof. Dr. Nurhan GÜMRÜKÇÜOĞLU October 2025 iii CONTENTS FOREWORD i CHAPTER I. A GRAPH-THEORETIC STUDY OF POLYGONAL CORE SPACER DENDRIMERS 1 Bilal DEMİR & Ümit SARP CHAPTER II. MAGNETIC-FIELD RESPONSIVE HYDROGELS: AN OVERLOOK TO THE DEFINITIONS, CLASSIFICIATIONS, SYNTHESIS METHODS AND APPLICATIONS 13 Demet AYDINOĞLU CHAPTER III. PHOTO-RESPONSIVE HYDROGELS: GENERAL OVERVIEW OF THE DEFINITIONS, CLASSIFICATIONS, SYNTHESIS METHODS AND APPLICATIONS 33 Demet AYDINOĞLU CHAPTER IV. MOF DESIGN AS AN ENZYME IMMOBILIZATION PLATFORM: BIOMINERALISATION 51 Elif OZYILMAZ CHAPTER V. BIO-CHARCOAL PRODUCTION POTENTIAL FROM PISTACHIO SHELLS 61 Sibel BAYIL CHAPTER VI. THE EVOLUTION OF WEST NILE VIRUS AND ITS INTERACTION WITH MOSQUITO VECTORS 67 Emrecan DOĞAN & Nergis ALKIŞ CHAPTER VII. PARATRANSGENESIS 81 Nergis ALKIŞ & Emrecan DOĞAN CHAPTER VIII. THE HISTORICAL DEVELOPMENT OF MATHEMATICS EDUCATION IN THE WORLD AND TURKEY: A CHRONOLOGICAL REVIEW 107 Alaattin Akyar & Oya Mert Coşkun CHAPTER IX. AN INVESTIGATION ON PSEUDO-SLANT SUBMANIFOLDS OF KÄHLER MANIFOLDS 135 Süleyman DİRİK & Ramazan SARI 1 CHAPTER I A GRAPH-THEORETIC STUDY OF POLYGONAL CORE SPACER DENDRIMERS Bilal DEMİR1 & Ümit SARP2 1(Assoc. Prof. Dr.), Balıkesir University, E-mail: [email protected] ORCID: 0000-0002-6638-6909 2(Dr.), İzmir Katip Çelebi University, E-mail: [email protected], ORCID: 0000-0002-1260-785X 1. Introduction raph theory is a powerful mathematical framework for modelling and analysing the relations between objects within a complex system. A graph is an ordered pair , where is a finite set of elements called vertices, and is a set of pairs of vertices, known as edges. In this abstract representation, vertices can represent any discrete objects—such as individuals, cities, or atoms—while edges represent the connections or relations between them, such as friendships, roads, or chemical bonds. This elegant simplicity allows for the study of structural properties, making graph theory a necessary tool in mathematics and computer science. The importance of graph theory lies in its various range of applications across numerous scientific and engineering disciplines. In computer science, it forms the basis for network design, data structures, and algorithmic optimization. In social sciences, it is used to model and analyse social networks and the flow of information. Furthermore, in operations research, graph theory is crucial for solving logistical problems, such as finding the optimal routes for transportation and delivery. Its ability to distill complex relational systems into a manageable mathematical structure provides a common language and a robust set of analytical tools, enabling researchers to uncover fundamental patterns and properties. G 8   MODERN RESEARCH AND INVESTIGATIONS IN NATURAL . . . Which concludes the proof. Calculating the total number of vertices and edges, a more valuable understanding of 's structure is crucial for computing degree-based topological indices. This requires a detailed analysis of the degrees of its constituent vertices. The degree of a vertex, , represents the number of edges incident to it and offers insights into the local connectivity of the graph. Degree sequence is the sequence of decreasing integers which are the degrees of the vertices. The number of vertices with the same degree is written in brackets as the power of the degree of the vertex. Observing the construction, we can categorize vertices based on their location and connectivity. The central core contains vertices whose degrees are influenced by both the cycle itself and the three emanating arms. Specifically, the three vertices from which the initial arms originate will have degree . Within the spacer path graphs ( ), internal vertices possess a degree of , while the terminal vertices of these paths (which act as branching points) exhibit different degrees depending on their generation level. Lastly, the outer vertices of the dendrimer branches represent the leaves, consistently having a degree of . Figure 3. The Polygonal Core Spacer Dendrimer Graph Lemma 2: The degree sequence of the Polygonal Core Spacer Dendrimer Graph is ( ) ( ) ( ) A GRAPH-THEORETIC STUDY OF POLYGONAL CORE SPACER DENDRIMERS   9 where and integers. The calculation of several prominent topological indices is fundamentally related to the degrees of the vertices incident to each edge. The formulas for indices such as the Second Zagreb, Randić, and are defined as sums over the entire edge set, with each term being a function of the endpoint degrees. Therefore, to facilitate a systematic and clear computation for the graph family, it will be better to obtain a partition of the edge set. For the remainder of this study, the subset of edges connecting a vertex of degree and a vertex of degree will be denoted by . Formally, this is expressed as: { } We begin by determining the cardinality of the edge set . These edges connect two vertices, both of degree . Assuming , vertices of degree 3 exist exclusively as the three attachment points on the central core. An edge in therefore arises only when two of these three core attachment vertices are adjacent. Our construction rule for ensures nonadjacent attachment, resulting in =0. For one such edge exists ( =1). When , there are two ( =2), and for , all three attachment points are adjacent, giving =3. This can be summarized by the formula: { } Next, we calculate the number of edges in , connecting a vertex of degree and a vertex of degree . Assuming and , such edges arise from two distinct sources. Firstly, within the central core, these edges link a core vertex with degree 2 to a core vertex with degree . The count of such edges is { }. Secondly, there are three edges connecting the degreecore attachment points to the initial degree-2 vertices of the spacer paths. Summing these contributions, we find: { } Now we focus on the edges in , where both incident vertices have a degree . Under the assumptions that and , these edges are found in two main locations within the graph. Firstly, within the central core, edges connect two adjacent core vertices, neither of which serves as 10   MODERN RESEARCH AND INVESTIGATIONS IN NATURAL . . . an arm attachment point. The number of such edges is given by { } Secondly, these edges are internal to the spacer path graphs. For each with , there are internal edges whose endpoints both have a degree of . Considering all such paths present in the graph, the total count of edges in is: { } In addition, we count of edges in , which connect a vertex of degree 2 to a vertex of degree . These edges represent the connections between the spacer path segments and the branching points throughout the dendrimer structure. Each branching point serves as both the endpoint of an incoming path and the starting point for outgoing paths. In total, the number of edges in is: Finally, by obtaining the number of edges incident to the terminal vertices (leaves), the partition of the edge set is complete. This number is obviously equal to the number of leaves which is Hence, we have proved the following lemma. Lemma 3: The edge set ( ) of the polygonal core spacer dendrimer graph can be partitioned has ( ) Now we are ready to give our main theorem. Since it is nothing but using Lemma 2 and 3 we omit the proof. Theorem 4: Let be the polygonal core spacer dendrimer graph where then: ( ) ( ) for ( ) ( ) A GRAPH-THEORETIC STUDY OF POLYGONAL CORE SPACER DENDRIMERS   11 √ ( ) √ ( ) √ √ √ ( ) √ ( ) √ An if we have: ( ) ( ) √ ( ) √ ( ) √ √ * ( ) ( ) + The complexity of these general formulas for the topological indices can be quite high. To enhance readability and provide more accessible insights, we present their simplified forms for the specific case of (i.e., for the first generation dendrimers) in the following corollary. Corollary 5: For the Polygonal Core Spacer Dendrimer Graph , under the conditions , the topological indices are given as follows: for √ √ √ √ And for a large core size, √ √ √ √ 12   MODERN RESEARCH AND INVESTIGATIONS IN NATURAL . . . 4. Conclusion In this work, we introduced and analysed the Polygonal Core Spacer Dendrimer Graph, denoted by . By formalizing its construction, we derived closed formulas for fundamental parameters such as the number of vertices and edges, the degree sequence, and a systematic partition of the edge set. These results enabled the exact computation of several widely used degree-based topological indices, including the Zagreb indices, Randić index, and Atom-Bond Connectivity index. The general formulas we obtained highlight the structural complexity of this class of graphs and provide a strong foundation for further mathematical and chemical investigations. The framework developed in this study can be extended in several directions. One natural line of future research is to vary the number of arms emanating from the polygonal core. While we fixed this number to three for consistency, allowing a larger or smaller number of initial branches could lead to new families of dendrimer graphs with distinct topological properties. Such generalizations may yield novel insights into molecular descriptors and their applications in and studies. Furthermore, exploring other topological indices or spectral properties within this broader framework remains an open and promising avenue for research. Bibliography Diestel, R. (2017). Graph theory (5th ed.). Springer. Gross, J. L., & Yellen, J. (2006). Graph theory and its applications (2nd ed.). Chapman and Hall/CRC. West, D. B. (2001). Introduction to graph theory (2nd ed.). Prentice Hall. Todeschini, R., & Consonni, V. (2009). Molecular descriptors for chemoinformatics. John Wiley & Sons. Trinajstić, N. (1992). Chemical graph theory (2nd ed.). CRC press. Bulut, M., & Akar, E. (2012). Dendrimerlerin önemi ve kullanım alanları. Teknik Bilimler Dergisi, 2(1), 5–11. Elsıkma, M., & Bacak-Turan, G. (2024). Çizge kuramında topolojik indeksler. In Proceedings of the 8th International Students Science Congress. Ghorbani, M., & Hosseinzadeh, M. A. (2010). Computing ABC index of nanostar dendrimers. Optoelectronics and Advanced Materials – Rapid Communications, 4(9), 1419–1422. 4. Conclusion In this work, we introduced and analysed the Polygonal Core Spacer Dendrimer Graph, denoted by . By formalizing its construction, we derived closed formulas for fundamental parameters such as the number of vertices and edges, the degree sequence, and a systematic partition of the edge set. These results enabled the exact computation of several widely used degree-based topological indices, including the Zagreb indices, Randić index, and Atom-Bond Connectivity index. The general formulas we obtained highlight the structural complexity of this class of graphs and provide a strong foundation for further mathematical and chemical investigations. The framework developed in this study can be extended in several directions. One natural line of future research is to vary the number of arms emanating from the polygonal core. While we fixed this number to three for consistency, allowing a larger or smaller number of initial branches could lead to new families of dendrimer graphs with distinct topological properties. Such generalizations may yield novel insights into molecular descriptors and their applications in and studies. Furthermore, exploring other topological indices or spectral properties within this broader framework remains an open and promising avenue for research. Bibliography Diestel, R. (2017). Graph theory (5th ed.). Springer. Gross, J. L., & Yellen, J. (2006). Graph theory and its applications (2nd ed.). Chapman and Hall/CRC. West, D. B. (2001). Introduction to graph theory (2nd ed.). Prentice Hall. Todeschini, R., & Consonni, V. (2009). Molecular descriptors for chemoinformatics. John Wiley & Sons. Trinajstić, N. (1992). Chemical graph theory (2nd ed.). CRC press. Bulut, M., & Akar, E. (2012). Dendrimerlerin önemi ve kullanım alanları. Teknik Bilimler Dergisi, 2(1), 5–11. Elsıkma, M., & Bacak-Turan, G. (2024). Çizge kuramında topolojik indeksler. In Proceedings of the 8th International Students Science Congress. Ghorbani, M., & Hosseinzadeh, M. A. (2010). Computing ABC index of nanostar dendrimers. Optoelectronics and Advanced Materials – Rapid Communications, 4(9), 1419–1422. 13 CHAPTER II MAGNETIC-FIELD RESPONSIVE HYDROGELS: AN OVERLOOK TO THE DEFINITIONS, CLASSIFICIATIONS, SYNTHESIS METHODS AND APPLICATIONS Demet AYDINOĞLU (Prof. Dr.) Yalova University, Armutlu Vocational School, Department of Food Processing, Yalova, Turkey. E-mail: [email protected] ORCID: 0000-0002-6104-7668 1. Introduction Hydrogels are defined as the soft materials constitue of water and three dimensional polymer networks. The polymer network structure provides shape, integrity and mechanical strength to the hydrogel, while the water enable softness. Due to their porous morphological structure and the hydrophilic groups they have, polymer networks can absorb up to thousands of times their own weight when placed in water. These polymeric materials are highly affected by the physical conditions of their surrounding environment, depending on their chemical structure. This unique feauture makes them to be very special, giving oppurtunities of usage in wide area varied from biomedical appliying to environmental practices, drug delivery systems, agriculture and food technologies (Hoffman, 2012). Hydrogels that change their swelling behavior in response to various stimuli such as pH, temperature, light end magnetic field etc. are called as “environmental sensitive” or “ stimuli-responsive” hydrogels. Depending on the chemical structures of functional groups and porous structure, they can undergo volume phase transition, which means becoming huge difference in 14   MODERN RESEARCH AND INVESTIGATIONS IN NATURAL . . . their volume, in responce to slightly change in environmental conditions (Stuart et al., 2010) Magnetic field-sensitive hydrogels can be described as hydrogels that exhibit swelling or shrinkage behaviour under the influence of a magnetic field. These hydrogels that are named also “ ferrogels” are formed from two components: a polymer network and micoor nano-paricles, having magnetic property (Zrinyi, 2000). The most common employed magnetic materials in magnetic hydrogel synthesis are superparamagnetic iron oxide nanoparticles (SPIONs). They render magnetic sensitive character to the hydrogel to undergo volume change, mechanical deformation and localized heating in response to magnetic field stimuli (Sun et al., 2008). This property offers the hydrogels to be used in various applications such as drug delivery, tissue engineering, actuators, sensors, and wastewater treatments. The first studies with magnetic hydrogels date back to the 1990s. (Zrinyi et al., 1997) In the study carried out by the same researcher, it has been demonstrated that the hydrogels can be directed remotely by gaining sensitivity to the magnetic field, when magnetic particles are included (Zrinyi, 2000). After this pionering work, especially advancements in nanoparticle synthesis and surface modification have enabled the design of various hydrogel compositions for use in some biomedical applications in which magnetic field utilized (Zhu, 2018). In the biomedical application, which constitues of vast majority of their use, magnetic hydrogels serve as drug carries and provide controlled drug delivery. In this way, at certain time intervals or the needed time and predetermined amount, drug supplied to specific body sites (Peppas et al., 2006). In tissue engineering, on the other hand, magnetic field is employed to have anisotropic tissue development in scaffolds formed from magnetic hydrogels and thus, it can be obtained the tissue structures very similar to natural ones (Castro et al., 2024). Apart from biomedical uses, they can be also successfully utilized in wastewater treatments. Here, magnetic hydrogels have a special advantage makes them superior compared to ordinary ones. This special property is that after application they can be easily removed from the environment with magnetic field effect, without need of regeneration with hard chemicals that can degrade the hydrogels in some occasions (Salahuddin et al., 2022). Today, high number of magnetic hydrogel structures at various composition have been available and gradually the new one is added. Particularly, as material MAGNETIC-FIELD RESPONSIVE HYDROGELS: AN OVERLOOK TO . . .   15 science advances, it is inevitable that designing magnetic hydrogels with desired properties that can meet specific needs. 2. Classification of Magnetic Hydrogels Magnetic hydrogels, which consist of a polymeric network and homogeneously dispersed magnetic nanoparticles or microparticles, can be classified in different ways as follows: 2.1. Based on Polymeric Matrix: 2.1.1. Natural Polymer-Based Magnetic Hydrogels Natural polymers found in nature and obtained by extraction from natural substances are the materials that attract attention with their non-toxicity and biodegradable structure. Especially in recent years, there has been a shift towards natural materials in polymers, with the increase in health and environmental issues. When natural polymers are placed in water, they generally do not dissolve immediately depending on their molecular sizes and structures, they initialy form hydrogel. This is because physical interactions between the polymer chains, such as ionic interactions, hydrogen bonds, and hydrophobic interactions, create weak crosslinks between the chains. Hovewer, increasing water content causes this natural hydrogel to degrade. To prevent this, it is possible to synthesize various natural hydrogels that remain stable in water by using stronger crosslinkers. Natural hydrogels are obtained as a result of cross-linking of natural polymers such as alginate, chitosan, gelatin, hyaluronic acid and cellulose derivatives, using appropriate methods. These hydrogels are unique for biomedical applications with their structures similar to natural tissues (Drury and Mooney, 2003). In particular, the incorporation of different chemical crosslinkers, polymers and microor nanomaterials into the structure has made natural hydrogels more stable and useful. In this way, it has become possible to impart various properties to resulting composite hydrogels. One of these modifications is the use of magnetic particles incorporated into the natural polymeric network structure. Encapsulation of magnetic nanoparticles into divalent Ca2+ crosslinked alginate hydrogels can be given as example to this group (Yuan et al., 2023). The obtained hydrogel exhibit both pH, originated from carboxylic functional groups in alginate molecules, and magnetic field sensitivities, occured from magnetic particles. 16   MODERN RESEARCH AND INVESTIGATIONS IN NATURAL . . . The distribution of magnetic particles within the hydrogel network is normally inhomogeneous, resulting in particle aggregation. Hovewer, in this hydrogel structure, the alginate polymer not only maintains the natural character of the structure but also facilities their homogenous distribution, by offering negative charged sites and ensuring that the positively charged nanoparticles are oriented towards these regions. It has been also possible to obtain natural magnetic hydrogels using a similar method with chitosan, another natural polymer. Unlike here, the positive protonated amino groups in chitosan helped to homogeneously distribution of magnetic particles, whereas the negatively charged functional groups in alginate hydrogels. Therefore, similar to alginate hydrogels, the oppositely charged magnetic particles, here negatively charged, have been used for homogenous distribution (Jayakumar et al., 2010). 2.1.2. Synthetic Polymer-Based Magnetic Hydrogels Synthetic polymers, as their names suggest, are not found in nature but are petroleum-based substances synthesized in laboratories from petroleum thorough various mechanisms and reactions. Many sources and reports mentioned their toxicity, and they have significant environmental risks due to their long-term environmental stability. Therefore, their use has always been a source of concern. Recently, efforts have been made to address these issues, particularly through hybrid versions made by reinforcing natural polymers and materials (Farzi and Gheysipou, 2023). Synthetic polymers, which offer excellent services in many areas, play a key role in the preparation of environmentally sensitive hydrogels, based on the functional groups they have. Among these, magnetic hydrogels prepared with synthetic polymers have achived very successful results. Hydrogels prepared by combining temperature-sensitive polymers and magnetic particles, in particular, exhibit advantageous behaviour, being both temperature and magnetic field responsive. Localized heat generated within the gel via external magnetic field, activates the regions containing the temperature sesnitive groups, causing them to expand or contract. These contraction and expansion create microgates and on-off switches, allowing drug release. For example, thermosensitive poly( N-isopropylacrylamide) (PNIPA) hydrogels containing magnetic particles exhibit localized warming under the influence of a magnetic field with the influence of the their magnetic components, causing the negatively temperature sensitive NIPA groups be affected, shrinking of the gels. (Nguyen et al., 2017). MAGNETIC-FIELD RESPONSIVE HYDROGELS: AN OVERLOOK TO . . .   17 Polyvinyl alchol (PVA), another temperature responsive polymer, show similar behaviour to PNIPA. Hovewer, the freeze-thaw stability of PVA provides an additional advantage (Zhang et al., 2011). Another example of this group, is polyethylene glycole-based magnetic hydrogels. But, a different strategy is employed here. The magnetic particles used in this hydrogels are functionalized with vinyl groups and then copolymerized. This process ensures homogenous distribution of the particles and also prevents them to release from the gel because of the covalent bond formation between the particles and polymer network (Meenach et al., 2010). 2.2. Based on Magnetic Particles 2.2.1. Ironoxide Nanoparticle-Based Hydrogels Superparamagnetic nanoparticles (Fe3O4, ϒ-Fe2O3), abbreviated as SPIONs, are among the most commonly used materials in the preparation of magnetic field-responsive hydrogels. Their biocompatible structure and, in particular, having FDA approval arethe primary reasons for their popularity (Chow, 2022; Mahmoudi et al., 2011). These nanoparticles are generally used after a surface coating with substances such as citrate or oleic acid to ensure homogenous dispersion. This allows for greater magnetization, providing higher yields, and increased efficiency. Awide variety of hydrogels containing Fe3O4 have been synthesized, particularly for drug delivery and biomedical purposes. Examples include Fe3O4loaded alginate (Ji et al., 2023), crosslinked lignin-agarose (Eivazzdeh-Keihan et al., 2022) and chitosan (Zhang et al., 2019) magnetic hydrogels. 2.2.2. Ferrite-Based Magnetic Hydrogels Magnetic particles called ferrites found in this class of hydrogels have high coercivity and therefore hard magnetic properties, maintaining their magnetic properties for extended periods even when applied magnetic field is removed. Therefore, ferrites (MFe2O4; M: Co, Mn, Ni, Zn) provide tunable features to hydrogels. For example, cobalt ferrite (CoFe2O4) is one of the most researched and used ferrite nanoparticles incorporated into hydrogel structures. Two prime examples of this group are cobalt ferrite-encapsulated polyacrylic acid (Farzaneh et al., 2021) and carboxymethyl cellulose (Uva et al., 2024). 2.2.3. Metallic Nanoparticle-Based Magnetic Hydrogels Metalic nanoparticles such as iron, cobalt and nickel constitue another group of materials that can be used in the preparation of magnetic hydrogels. Hovewer, 24   MODERN RESEARCH AND INVESTIGATIONS IN NATURAL . . . hydrogels containing functional groups such as carboxyl or amines enable the removal of heavy metals such as Pb2+, Cd2+, and Cu2+ from industrial wastewater (Zou, 2024). If this hydrogel is a magnetic hydrogel, the gel fragments are easily collected by the magnetic field after the adsorption process is completed and can be reused multiple times. For example, the cationic chitosan–Fe3O4 hydrogel is highly effective in removing anionic contaminants. 4.2.2. Oil–Water Separation Magnetic hydrogels can be transformed into materials that remove oil and petroleum waste from industrial wastewater by modification with hydrophobic groups. Using these materials creates an affinity based on hydrophobic interactions between the functional groups and the oil and petroleum molecules. This affinity allows oil wastes to be easily and selectively separated from water. The function of the magnetic particles in these materials, on the other hand, is that after the gel has adsorbed sufficient oil and reached saturation, it can be separated and reused simply by applying an external magnetic field, eliminating the need for laborious filtration and centrifugation. (Yin et al., 2020; Choudhary et al., 2024). Another point where these materials can be particularly useful is their potential to clean petroleum-based contamination accumulated on the sea surface. Floating these gels on the sea surface can provide active oil removal. If they are constructed with robust cross-linked structures, they can be used dozens of times without undergoing degradation under challenging conditions such as currents and waves. In fact, by adding some additives such as antimicrobial agents, multi-purpose hydrogels can be prepared, and microbial treatment can be provided while removing oil pollution (Gao et al., 2021). 4.3. Industrial Applications 4.3.1. Soft Robotics and Actuators In soft robotics, actuators are desired to have structures that replicate the natural muscle system. Magnetic hydrogels meet this exact need. When exposed to a magnetic field gradient, the nanoparticles within these hydrogels align, enabling the hydrogel to exhibit reversible mechanical movements (bending, stretching, and contraction) similar to biological tissues. Therefore, these materials are among the most preferred materials in soft robotics applications (Shen et al., 2020). MAGNETIC-FIELD RESPONSIVE HYDROGELS: AN OVERLOOK TO . . .   25 Another advantage and potential application of magnetic hydrogels in this field could be the production of wirelessly operated, invasive surgical instruments during minimally invasive procedures. For example, anisotropic PNIPA–Fe3O4 hydrogels have been prepared as tweezers for grasping micro-scale objects. This material combines these two properties: the viscoelastic structure contributes to biocompatibility, while the magnetic portion provides precise, controllable movement (Perera et al., 2024). 4.3.2. Sensors and Diagnostics Unlike processes involving changes in the hydrogel structure induced by magnetic fields in magnetic hydrogels, sensor applications involve a different process. In these processes, the hydrogel responds to its environment by swelling or shrinking, while the nanoparticles within the structure are simultaneously affected by this swelling or shrinkage, changing their alignment. These altered alignments also create a change in the permanent magnetization, converting it into an externally measurable signal. This indirect measurement method offers the potential for magnetic hydrogels to be used in the production of various sensors, such as pressure and chemical sensors (Zhao et al., 2023; Zhang et al., 2023). This property has led to their successful use in the diagnosis of various diseases. For example, enzyme-immobilized magnetic hydrogels are bonded to substrates, changing their stiffness and thus the nanoparticle orientation, resulting in externally readable magnetic signals. (Yachi et al., 2000). A similar behavior can be achieved with temperature-sensitive gels. In these dual-effect gels, when the swelling and shrinkage behavior of the gel changes due to temperature, this change can be indirectly read as a magnetic signal (Osada et al., 2004). 5. Conclusion Magnetic field-responsive hydrogels, obtained by integrating magnetic particles into the hydrogel network, combine the viscoelastic structure of the hydrogel network, its swelling and shrinkage behavior and also volume phase transition in response to certain stimuli, and its adsorption properties with the magnetization properties of the magnetic particles in a single material. These exceptional properties allow these hydrogels to have numerous applications, ranging from drug delivery and tissue engineering to the production of diagnostic sensors, soft robotics, and the separation of pollutants from industrial wastewater. 26   MODERN RESEARCH AND INVESTIGATIONS IN NATURAL . . . 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Nanomaterials (Basel). 8(10), 810. doi: 10.3390/nano8100 33 CHAPTER III PHOTO-RESPONSIVE HYDROGELS: GENERAL OVERVIEW OF THE DEFINITIONS, CLASSIFICATIONS, SYNTHESIS METHODS AND APPLICATIONS Demet AYDINOĞLU (Prof. Dr.) Yalova University, Armutlu Vocational School, Department of Food Processing, Yalova, Turkey. E-mail: [email protected] ORCID: 0000-0002-6104-7668 1. Introduction Hydrogels are defined as three-dimensional polymer networks having ability to absorb large amount of water without dissolving. This property receives great attention and causes to find themselves many application areas varied from biomedical applying to environmental practices, drug delivery systems, agriculture and food technologies (Hoffman, 2012). One of the most beneficial properties of hydrogels is their exhibition swelling behaviour depending on varied environmental conditions such as pH, temperature, light, magnetic field etc. These hydrogels carrying certain functional groups, called as “stimuli-sensitive” hydrogels undergo huge volume changes in response to very slightly alteration in environmental conditions (Stuart et al., 2010). Light, as an environmental stimuli, has a special importance on hydrogel practiceses due to the capability of remotely application and precisely control with adjustable wavelength and intensity. (Ruskowitz and DeFrost, 2018).This unique ability is especially advantageous in not only biomedical applications but also soft robotics and mictofabrication productions. (Ding et al., 2020). 40   MODERN RESEARCH AND INVESTIGATIONS IN NATURAL . . . In spite of these advantages, there is some difficulties in preparation of photothermal hydrogels. For example dispersion of nanomaterials can become the hardest stage of the synthesis, leading to aggregation formation. Besides a vast majority of the nano particles used in photothermal hydrogels are known as toxic and therefore especially long-term use carries some concerns. These negative effects cause to new researches. Fortunately the surface functionalization of the naoparticles has emerged to overcome these disadvantages and has become one of the most beneficial method to use in the preparation of many nanocomposite materials (Hribar et al., 2011). 2. 5. Hybrid Strategies To enhance the positive sides and to eliminate the difficulties, the hybrid system has become a very beneficial approach. As in a number of different cases, here, construction of multple systems consisting of photosensitive parts has been a solution for preparaion and usage challenges of photoresponsive hydrogels. For example, if the photoreactive substance that will be used in the gel synthesis cause the hydrogel to have mechanically poor structure, decreasing mechanical strength, it has to be supported with a robust structure such as a strongly crosslinked polymer network, by forming a hybrid gel. Otherwise it may undergo degradation which is undesired situation especially in bimedical applications, such as uncontrolled drug delivery and complexity in many processes. (Hoffman, 2012). 3. Applications 3. 1. Drug Delivery Controlled drug delivery refers to the delivery of a drug to a specific area of the body and its dosing at the desired time and quantity. The material used to implement this concept is most often a suitable drug-loaded hydrogel. Gels sensitive to pH, temperature, magnetic field, and light are unique materials for this purpose. Among these, magnetic field and light are particularly superior because they can be remotely controlled and a highly sensitive response can be achieved by fine-tuning the necessary parameters externally. Photosensitive hydrogels, like many other gel types, find widespread application in drug delivery systems, causing that the researches on this subject have being continued and different hydrogel constructions have being designed. For instance, in the study performed Kloxin et al. ,the photoresponsive hydrogels PHOTO-RESPONSIVE HYDROGELS: GENERAL OVERVIEW OF THE . . .   41 incorporated o-nitrobenzyl groups have been loaded with protein and observed the UV light effect. It was recorded that these hydrogels have been succesful in controlled protein delivery (Kloxin et al., 2009). In another study it was reported that use of the photoresponsive hydrogels that sensitive to NIR has achieved to deliver to deeper tissues that UV can not. (Nazemidashtarjandi et al., 2024). In addition of these, especially delivery of ocular drugs with photosensitive hydrogels have been shown to exhibit precisely controlled over kinetics, promising new applications. (Abdelmohsen et al., 2023). 3.2. Tissue Engineering and Regenerative Medicine Tissue engineering and regenerative medicine are the two of the scientific fields that grow rapidly in recent years. With the researches, conducted by using new designed materials, it has being tried to put forward both effective and efficient in terms of long-term usage and patient compliance etc. Hydrogels, with their extracellular matrix-like nature, offer great oppurtunities to the biomedical practices (Hoffman, 2012). Controlled drug delivery application that uses bioactive and similar substances, make the stimuli sensitive hydrogels to be powerful for these practices, providing them to have growing attention. With the use of injectable and implantable these materials, it is not aimed only delivering drug which will be routed to specicif site in body, as it is needed, for remediation, also it is establihed to send bioactive molecules for recovering tissue. Among them, photoresponsive hydrogels and their usage in drug delivery systems or active substance are beneficial and effective due to their precisly control remotely, without any disturbance to both biological hydrogel surrounding and patient compliance. Particularly, photothermal hydrogels have significant importance due to their ability to create microchannels, as these routes which are used for release of growth factors and contribution to cell migration and differentitation.(Fonseca et al., 2022). Similar to abovementioned drug delivery systems, one of the usage aims of this practices is to sent bioactive molecules to the wound regions. In addition of this, their most advantageous feature is that, unlike classical bandages, it is not reqiured to constantly open the bandage to apply medication. The dressing placed on the wound, via an external stimulus—usually light or a magnetic field—transfers the bioactive substance it contains to the affected area, promoting tissue healing. In some cases, antimicrobial agents can also be incorporated into the gel the wound, in order to prevent infection possibility 42   MODERN RESEARCH AND INVESTIGATIONS IN NATURAL . . . that increase with opening the bandage. At the same time, soft and moist texture of hydrogels creates a comfortable environment for the patient. The photoresponsive hydrogels containing photocleavable o-nitrobenzyl groups that have been shown to exhibit controlled release growth factors and antimicrobial substances to the wound region, with light exposure can be given as a typical example for this application. (Kloxin et al., 2009). 3.3. Environmental Remediation The most common use of hydrogels for environmental applications is the removal of heavy metals and certain dyes through adsorption. Numerous examples of this are available in the literature. However, due to their hydrophilic nature, hydrogels are insufficient for removing organic contaminants. To overcome this problem, an approach of use for photocatalytic agents such as titanium dioxides, graphitic carbon nitride etc.,capable of degrading organic substances under the influence of light. In this context, these substances have been involved in polymer networks and tested their organic pollutant removal capacities and efficientness (Liu et al., 2024). As in many other areas, reusability is a key feature in water treatment, providing advantages in many ways, particularly economic ones. A significant advantage of using photosensitive hydrogels is that, unlike traditional reusability, harsh chemicals are required for material regeneration, resulted in several damages to structural integrity of the hydrogels. At this point, photosensitive hydrogels eliminate the need for these chemicals by directly applying light at the desired intensity, removing contaminants and ensuring regeneration. In this context, hydrogels containing photoisomerizable groups are considered particularly successful in this regard. Photoisomerizable groups within the contaminated hydrogel can change their configuration under the influence of light, easily altering their affinity for contaminants, and facilitating regeneration. For example, the ability of titanium dioxide-containing hydrogels to be highly efficiently regenerated and reused after dye absorption from wastewater (Wang et al.,2008). 3.4. Soft Robotics Soft robotics is another area where hydrogels can be used. Both their soft structure and the ability to respond to environmental stimuli offer potential applications in this field. Depending on their chemical and morphological structure, hydrogels can respond to remotely sent stimuli such as light and PHOTO-RESPONSIVE HYDROGELS: GENERAL OVERVIEW OF THE . . .   43 magnetic field by bending, swelling, and shrinking. These characteristics demonstrate their potential in the production of soft robots capable of remote control, dynamic, and reversible shape changes. (Ding et al.2020). For example, Kuenstler et al. reported that azobenzene-functionalized hydrogels bend to varying degrees with alternating UV and VIS light application (Kuenstler et al., 2020). Unlike the other photosensitive hydrogels, when the same application was performed with photothermal hydrogels, such as those incorporating gold nanorods or carbon-based nanoparticles, localized heat was generated using NIR light, and local swelling, shrinkage, and bending movements within the hydrogel were observed (Kim et al., 2022). 3.5.4D Printing and Smart Manufacturing 4D printing can be termed as an advanced form of 3D printing technology. The fourth dimension refers to time that allow 3D printed objects to take new shape over time in response to certain environmental conditions. Researches on 4D hydrogels, which came into our lives 15 years after the first 3D hydrogel production in 2000, is still new and the studies are increasing rapidly. Among the all environmental sensitive hydrogels, light-responsive hydrogels are the most attrractive ones and ideal candidates because they can be precisely patterned and later activated by irradiation (Yang et al., 2024). For instance it was demonstrated the hydrogel structures that exhibit programmed shape morphing under light, illustrating the potential of these materials in adaptive devices (Lui et al., 2019). Applying 4D technology and coupling multiple photoactive chemistries within a single hydrogels, it has been possible to create a hydrogel allows multistimuli responsiveness and hierarchical shape transformations (Guo et al., 2024). The emerging of 4D printing technology and integration with biofabrication technologies offer more opportunities for dynamic implants, self-adjusting sensors, and adaptive microfluidic devices. For example, 4D-printed hydrogels have been used to create self-folding micro-fluidic channels that respond to light, enabling applications in lab-on-a-chip systems (He et al., 2016). 4. Challenges and Future Perspectives Despite remarkable advances, several challenges remain for widely use of light sensitive hydrogels. One limitation is the poor penetration of light into 44   MODERN RESEARCH AND INVESTIGATIONS IN NATURAL . . . biological tissues, particularly for UV and visible wavelengths. Although NIRresponsive systems provide improvement, penetration depth is still limited to a few centimeters (Nazemidashtarjandi et al., 2024). Strategies to address this include nanoparticles that convert NIR to UV/visible light locally (Wang et al., 2021) and implantable optical fiber systems for delivering light to deep tissues. Another challenge is long-term biocompatibility. Some photoactive molecules (e.g., azobenzene derivatives) or nanomaterials (e.g., carbon nanotubes) may raise concerns regarding cytotoxicity or immunogenicity (Londoño-Berrío et al., 2022; Yu et al., 2008). Therefore, currents studies have focused on exploration of biodegradable, non-toxic photoactive agents and safer nanomaterial alternatives. For instance, biocompatible photoresponsive peptides have being searched as alternatives to synthetic chromophores, offering improved safety profiles for in vivo applications (Zhou et al., 2024). Manufacturing and scalability also require attention. While photopolymerization and 3D printing techniques enable perfectly control at the laboratory scale, translating these processes to industrial-scale production remains complex and costly (Iftekar et al., 2023). To solve this problem, various efforts have focused on developing scable photopolymerization procedure for large-scale production of hydrogel-based medical devices (Lim et al., 2020). 5 .Conclusion Photosensitive hydrogels, a member of the environmentally responsive hydrogel group, offer superior properties to many other hydrogel classes due to being controlled remotely with precision. Depending on the properties of photoactive agents, they can be used in various application areas by preparing different photosensitive hydrogel structures via different mechanisms such as photoisomerization, photocleavage, photodimerization, and photothermal conversion. Biomedical and medical practices are among the most prominent of these applications. In these, in addition to controlled drug release, these hydrogels are used in fabrication of soft robotics, wound dressings, and tissue scaffolds, particularly and in particularly microsurgery. Owing to their ability to undergo conformational changes under the influence of light, they can be regenerated repeatedly, especially in water treatment processes, without the need for harsh chemicals. Their remote control, unlike many other applications, prevents damage to the hydrogel’s surroundings. 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The biomimetic strategy is another strategy for the encapsulation of biologically active compounds due to mild conditions. Inspired by this phenomenon, a biomimetic mineralisation strategy has been developed to accommodate natural enzymes with metal organic frameworks (MOFs). Furthermore, this method will significantly increase the potential to use functional biocatalysts in applications requiring improved thermal stability, tolerance to organic solvents or extended shelf life, such as industrial catalysis and biopharmaceutical application (Liang et al., 2015). This immobilization strategy can prolong the thermal and chemical stability of the enzyme without the use of a co-precipitation agent, thus making this process economical, easy and highly efficient. (Nadar and Rathod, 2018; Shieh et al, 2015). The immobilization of biocatalysts with nanomaterials has significantly supported the development of biocatalysis, making it an indispensable part of catalysis industries today. Metal-organic frameworks (MOFs) constructed from organic linkers and metal ions or clusters have aroused significant interest for the immobilization of biocatalysts in recent years. (Ascioglu et al., 2024; Ozyilmaz et al., 2023b) The progress of MOFs in recent years as a versatile host for a range of biocatalysts, including natural enzymes, nanozymes and organism-based biocatalysts, and the subsequent introduction of MOFs as biocatalysts are discussed. Furthermore, the stimulus-responsive properties of MOFs themselves or the additional functionalization of protein, polymer and peptide in/on the MOF are outlined, enabling biocatalysts to have controllable and tunable behaviour, which could unlock new potentials in biocatalysis. 3. Conclusion Immobilization of biocatalysts with nanomaterials has significantly promoted the development of biocatalysis and has become an indispensable part of biocatalysis industries today. As a kind of engineered porous material with numerous structural possibilities, metal-organic frameworks (MOFs) have gained great progress in recent years. By exploiting the protection effect of MOF scaffolds, the added enzyme can withstand various harsh environments compared to the native enzyme, even under protein denaturing conditions. Biomimetic mineralisation is directed towards the development of a general method to adopt the selfassembly processes found in natural biological systems and encapsulate MOF DESIGN AS AN ENZYME IMMOBILIZATION PLATFORM: BIOMINERALISATION   57 bioactive molecules in protective outdoor environments. The easy, fast and costeffective process of biomimetic mineralisation will open new possibilities for the use of biomacromolecules. 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Bioprocess and Biosystems Engineering, 35, 493-502. 61 CHAPTER V BIO-CHARCOAL PRODUCTION POTENTIAL FROM PISTACHIO SHELLS Sibel BAYIL Gaziantep University Health Services Vocational School, Department. of Medical Services and Techniques, 27000, Gaziantep, Turkey E-mail: [email protected] ORCID: 0000-0003-0254-6915 1-Introduction Charcoal has traditionally been used in various areas in our country. Charcoal mines operate to meet this need. However, coal ash contains toxic substances and, as a result, poses a threat to the environment and human health. Biomass resources, also known as agricultural and forest wastes, are widely used. These wastes can be categorized as fertilizer, wood waste from the forestry and forestry industry, and food industry residues. These biomassbased materials are used for energy production both directly as biomass and as biofuels. On the other hand, agricultural waste is increasingly creating environmental problems. Waste left over from agricultural activities, a crucial component of sustainable development and sustainable environmental living, unfortunately poses significant environmental problems. In addressing these environmental challenges, it’s necessary to utilize their energy potential. This will both address the problems caused by agricultural waste and transform them into beneficial resources. Biocarbonization is the most optimal and economical way to dispose of agricultural waste without harming the environment or incinerating it. Therefore, this study examines the potential and advantages of converting pistachio shells, a common agricultural waste, into biochar. Energy sources such as coal, oil, and natural gas are widely used worldwide, and the resulting waste creates significant economic and environmental problems. Charcoal has traditionally been used in various areas in our country. Charcoal mines operate to meet this need. Charcoal is the decomposed solid fraction 62   MODERN RESEARCH AND INVESTIGATIONS IN NATURAL . . . obtained by carbonizing woody residues through heat treatment in an airless environment (Göker and Akbulut, 1994). Charcoal is produced primarily for urban markets, and its market share is growing with increasing populations and urbanization. Especially in underdeveloped and developing countries, charcoal is an important energy source used by urban households and the hospitality and service sector, whose wood raw material needs are met by natural or plantation forests. Charcoal is produced by stacking wood in a parabolic or patterned manner using a method called torluc (Yang and et al., 2014). Figure 1: Paraboloidal Stacking and Covering with Soil Cover As seen in Figure 1, after the stacking of charcoal wood is completed, the pole in the middle is removed and embers are thrown into it to begin the burning process. A circular groove called a neck is opened from any part of the torluk to ensure the fire progresses. Bozkurt and Göker (1981) described this stage as follows: “At first, water vapor rises from these holes, then later, yellow smoke rises. Finally, a blue color, consisting of carbon monoxide, appears. When the blue color appears, charring is complete.” In a simple torment, charring takes approximately 10-14 days, depending on the stack volume (Güvenli and Daşdemir, 2017). Therefore, the environmental damage caused by the length of the process and the carbon dioxide emissions following combustion is obvious. Using this method is not recommended due to factors such as loss of green space, greenhouse gas production, and the harmful effects of toxic substances in the smoke produced after the combustion of charcoal. Biocharcoal production has been implemented in recent years to improve charcoal production methods in line with the green transformation initiated after the Paris climate agreement and to mitigate the resulting biological damage to the environment. BIO-CHARCOAL PRODUCTION POTENTIAL FROM PISTACHIO SHELLS   63 2Obtaining biochar by pyrolysis method Biochar enables the conversion of biomass into technologically suitable solid, liquid, and gaseous products using the pyrolysis method. As a carbonized material rich in functional groups, biochar has the potential to find applications in a wide variety of areas. Using waste generated by agricultural activities in our country, which has a wealth of agricultural land, as biomass presents an advantageous alternative. In one study, the pyrolysis method used to produce biochar from selected plant and animal product waste was investigated and the results of previous research on the subject were examined (Kan and et al., 2016). Researchers focusing on biochar have primarily conducted studies on which pyrolysis methods and parameters are more effective on biochar yield. To this end, they have applied fast and slow pyrolysis methods to various biomasses at specific temperatures, mostly between 300 and 700 °C. Reported research results indicate that slow pyrolysis is necessary to increase biochar yield, although there are differences depending on the biomass type and application parameters. Laird (2008) reported that biochar yields of up to approximately 50% can be produced through slow pyrolysis (Laird, 2008). 3Use of pistachio shells as biomass Dry-processed olive pomace and the outer shells of nuts (walnuts, pine nuts, hazelnuts, and almond shells) are characterized by low sulfur, nitrogen, and ash contents. Their carbon content is 1.5% higher by weight than wood, and their lignin content is also higher (48.28%). Charcoal obtained from the shells is characterized by the absence of harmful impurities, high mechanical strength, and very fine pores. Biocarbon can be used for charcoal or hookah charcoal production. Bio-Briquette Charcoal is produced using environmentally friendly equipment that allows the carbonization of small-fraction raw materials (5-20 mm), such as olive pits, hazelnut shells, and fruit tree seeds, as well as chopped branches, by high-temperature pyrolysis. The outer shells of nuts, such as pistachios, are characterized by low sulfur, nitrogen, and ash contents (Bilandzija et al., 2012). Some of the properties of Outer Hard Shell Coal are as follows: • Low ash and S content • No smoke or odor • Less SO2 formation than coal 64   MODERN RESEARCH AND INVESTIGATIONS IN NATURAL . . . • Longer burning time • Because it is organic, it does not release toxic (Carcinogenic) substances (Lijinsky and Ross, 1967). 4Conversion rates of agricultural waste into biochar in Turkey The amount of waste for selected field crops was determined based on the harvested land area (Sümer and et al., 2016). Using these values from Turkish Istatistical Institue agricultural statistics and the coefficients and usability rates determined by CEC (California Energy Commission) (2015), the annual amount of waste and usable waste left on the field for selected crops were calculated. The waste coefficients and usability rates for selected crops are given in Table 1. Table 1. Field crop residues and biochar conversion potential Product Wastes Harvested area Waste Coefficient ton/year Waste quantity ton/year Available rate Available waste ton/year biochar conversion rate ton\year Biochar potential ton/year Crop Handle 6 861 686 1.00 6 847 963 0.50 34 240 35 11 984 Sugar beet Handle 2 752 621 0.51 1 401 084 0.50 7 005 35 2452 Cotton Handle, gin waste 4 340 004 0.32 1 384 461 0.50 6 922 35 2 423 Sunflower Handle 6 851 737 0.18 1 233 313 0.50 6 167 35 2 158 Paddy Handle, Shell 1 158 561 0.74 860 811 0.50 4 304 35 1 506 Tomato Handle 1 871 637 0.32 600 795 0.50 3 004 35 1051 Potatoes Handle 1 538 022 0.30 455 255 0.50 2 276 35 797 According to Turkish istatistic data, the pruning residues and biochar conversion rates of pistachio shells are shown in Table 2. BIO-CHARCOAL PRODUCTION POTENTIAL FROM PISTACHIO SHELLS   65 Table 2: Pistachio shell pruning waste and biochar conversion potential Number of trees bearing fruit Pruning coefficient tree kg/year Pruning waste ton/ year Available rate Usable pruning waste ton/year biochar conversion rate ton\year Biochar potential ton/year Pistachio 40 597 427 8.8 357 257 0.70 250 080 35 87 528 When we compare the ratios of field crop waste to orchard crop pruning and hard shell waste, it appears that pistachio shells have a very high biochar potential and are the best alternative in this regard. Pruning waste generated in fruit production areas in pistachio-growing regions is generally burned or abandoned in vacant lots. Researchers emphasize that these wastes can be utilized through landfill, composting, and recycling, in addition to incineration (Şeflek and et al., 2006). 5-Conclusions Efforts are being made to address the world’s energy challenges, such as the increasing global population, dwindling energy resources, and global warming resulting from the use of fossil fuels, through alternative energy sources. Biomass energy is one such solution. Unlike traditional methods, biomass must be converted into energy or material forms compatible with today’s technology. Coal ash contains toxic substances and, as a result, poses a threat to the environment and human health. Biomass energy source biochar can be converted into a versatile and advantageous material for many applications, including soil remediation, energy storage, and the removal of organic and inorganic pollutants. The most important point in the use of biomass energy is that food used for human consumption should not be used as raw materials. Instead, waste should be utilized. Valorizing biomass waste, which is often left to decompose, and transforming it into high-value-added products also contributes to the elimination of waste that contributes to environmental pollution. It will also reduce greenhouse gas emissions of carbon dioxide and particulate matter. Biomass resources, such as agricultural and forest waste, are widely used. This study demonstrates the potential for converting pistachio shells, one of these wastes, into biochar. In the Southeastern Anatolia region, where pistachios are 72   MODERN RESEARCH AND INVESTIGATIONS IN NATURAL . . . Figure 1. Replacement of local WNV strains by evolved strains (Hadfield et al., 2019) 3.2. Co-evolution The concept of co-evolution is defined as the continuous and dynamic shaping of mutual selection pressures between pathogens and their hosts. In this process, the host develops immunity or resistance mechanisms against infection, while the pathogen evolves new strategies to adapt to this. Duggal and colleagues’ (2014) study shows that the relationship between West Nile virus (WNV) and house sparrows (Passer domesticus) in North America is a strong example of such a process (Duggal et al., 2014). After WNV entered the US in 1999, the virus spread rapidly via Culex mosquitoes and songbirds. House sparrows emerged as one of the most important reservoir hosts in this cycle. The study examined how the virus and host co-evolved by infecting house sparrows with WNV isolates obtained in different years from 1999 to 2012. The results showed that the initial NY99 genotype became less successful in sparrows over time, whereas the WN02 and then SW03 genotypes, which became dominant from 2002 onwards, produced much higher viremia levels in sparrows. This adaptation increased the infection rate in mosquitoes and strengthened the epidemiological success of the virus. Additionally, mutations in the NS2A and E proteins (Figure 2) have been associated with higher mortality rates in sparrows (Duggal et al., 2014). THE EVOLUTION OF WEST NILE VIRUS AND ITS INTERACTION . . .   73 Figure 2. Amino acid differences between NY99 and WN02, SW03 genotype isolates (Duggal et al., 2014). In response, house sparrows have also strengthened their immune responses, developing resistance to NY99, especially in the early stages. However, new variants of the virus have overcome these immune barriers, becoming more contagious and pathogenic. This reciprocal change is considered a continuous host–pathogen race within the framework of the Red Queen hypothesis. From an ecological perspective, it is suggested that house sparrow populations have declined by an average of approximately 3% annually, with WNV playing a significant role in this decline (Duggal et al., 2014). This study provides strong evidence of co-evolution between WNV and house sparrows, clearly demonstrating that arboviruses exert important evolutionary pressures not only on human health but also on ecosystems and bird populations. In another study, Culex pipiens mosquitoes were exposed to two different virus strains: wild-type WNV (WT) and the MP20 strain, which was experimentally evolved to be better adapted to mosquitoes and has a high internal replication capacity. The findings showed that these two strains had distinctly different effects on the life history traits of mosquitoes. No significant reduction in lifespan was observed in mosquitoes exposed to WNV WT. In 74   MODERN RESEARCH AND INVESTIGATIONS IN NATURAL . . . contrast, the MP20 strain significantly reduced the survival time of mosquitoes, increased egg production in the early stages but decreased reproductive capacity in the later stages. Furthermore, a similar loss of lifespan was recorded even in mosquitoes resistant to the MP20 strain (Ciota et al., 2013). These findings are consistent with the theoretical framework known as the “virulence-transmission trade-off hypothesis.” The virus’s ability to replicate at high levels within the mosquito provides an advantage in terms of viral fitness in the short term, but it limits the virus’s long-term transmission capacity by shortening the host’s lifespan. In other words, there is a conflict between the virus’s intra-host success and its transmission capacity at the population level. This situation is considered an important limiting mechanism in explaining the relatively stable evolutionary course of arboviruses (Ciota et al., 2013). The study also shows that virulence can arise not only as a result of infection but also through resistance mechanisms to infection. Mosquitoes resistant to the MP20 strain experienced a reduction in their lifespan despite not carrying the virus. This finding reveals that mosquito immune responses are costly and can incur different costs depending on the specific characteristics of the virus strain. Consequently, this study suggests that the interaction between arboviruses and mosquitoes is not neutral but rather constitutes an important biological pressure shaping the coevolution of the virus and the vector (Ciota et al., 2013). 3.3. Effect of Temperature The distribution and intensity of vector-borne pathogen transmission are strongly influenced by the complex interaction between vector competence, environmental temperature, and pathogen genetics. Pathogens typically evolve to maximize their fitness, which is a function of transmissibility and virulence. In this context, temperature can determine both the latitudinal limit and the highaltitude limit of pathogen transmission, especially when the extrinsic incubation period (EIP) is longer than the vector’s lifespan. Temperature also causes changes in transmission intensity through its effects on EIP, vector lifespan, and feeding rate (Kilpatrick et al., 2008). The transmission dynamics between the NY99 genotype, the original strain of WNV that entered the United States in 1999, and the WN02 genotype, which was detected in 2001 and spread across the American continent, are being studied in the primary vector, the Culex pipiens mosquito, depending on temperature and the time elapsed since the ingestion of infected blood THE EVOLUTION OF WEST NILE VIRUS AND ITS INTERACTION . . .   75 (incubation period). Previous studies have shown that WN02 is more efficient than NY99 in infecting, transmitting, and spreading Culex mosquitoes. The rapid spread of the WN02 genotype has been associated with a shorter EIP in Culex mosquitoes. In the current laboratory study, researchers found that the advantage of the WN02 genotype over the NY99 genotype increased with the product of incubation period and temperature. This critical finding suggests that higher temperatures may have facilitated the establishment and spread of the WN02 genotype. Thus, the WN02 genotype appears to be better adapted to warmer conditions than NY99. This result highlights the importance of understanding vector-pathogen-environment interactions and the role of pathogen evolution in transmission (Kilpatrick et al., 2008). Another important finding of the study is the nonlinear, sharp acceleration of transmission with increasing temperature for both WNV lineages. Regression analyses showed that the rate of transmission cannot be fully explained by traditional degree-day models based solely on the product of temperature and time (Kilpatrick et al., 2008). The researchers found that the model that best explains the change in transmission includes a degree-day term that incorporates the incubation period and the fourth power of temperature. This model indicates that WNV transmission exhibits an exponential increase with temperature. The practical implication is that relatively small increases in temperature (e.g., the projected 2°C increase in global temperatures) could have a significant and exponentially increasing effect on transmission (Kilpatrick et al., 2008). For example, while the linear degree-day model predicts that an increase from 28∘C to 30∘C would increase transmission by only 0.9%, the tT4 model predicts that the same temperature increase would increase transmission by 7.8%. This suggests that traditional models may significantly underestimate the effects of global warming on WNV transmission. 4. Conclusion The evolutionary success and epidemiological dynamics of the West Nile virus (WNV) are too complex to be explained by a single factor; they lie at the intersection of the virus’s intrinsic genetic potential, the delicate ecological balance it establishes with vectors and hosts, and abiotic environmental conditions. The data presented in this study reveal the fundamental mechanisms shaping the evolution of WNV and their real-world implications. At the heart of the discussion are the genetic principles underlying the virus’s extraordinary 76   MODERN RESEARCH AND INVESTIGATIONS IN NATURAL . . . adaptive capacity and how this capacity translated into a concrete evolutionary advantage, particularly during its spread in North America. The high mutation rates inherent in RNA viruses and the quasispecies population structure resulting from this rate are the cornerstone of WNV’s evolutionary strategy. The virus exists as a “cloud” of genetically related but distinct variants rather than a single dominant genotype. This situation provides the virus with a kind of “genetic insurance” mechanism; when faced with new selection pressures, such as changing host immune pressures or the physiology of different vector species, one of the ready variants within the population can be rapidly selected and adapted. However, this adaptation process is constantly “reset” by population bottlenecks that occur during transmission events, such as the jump from mosquito to bird or bird to mosquito. The dramatic reduction in genetic diversity with each transmission event leaves the virus’s evolutionary trajectory open to random genetic drift events. Therefore, the evolution of WNV appears as a dynamic process in which both natural selection and chance play a role, within a cycle of constant diversification (thanks to a high mutation rate) and contraction (thanks to transmission bottlenecks). The most striking practical evidence for this theoretical framework is the evolutionary path the virus took in North America following its entry into New York in 1999. The continent served as a giant natural laboratory for the virus. The replacement of the initial NY99 genotype by more “successful” genotypes such as WN02 and SW03 within a few years is more than a simple displacement; it is an observable adaptive evolutionary process. At the heart of this change lies a seemingly minor mutation: a single amino acid change (E-V159A) in the virus’s envelope protein. However, the consequences of this mutation are profound: the WN02 genotype has gained the ability to be transmitted more efficiently by the continent’s most common vectors, Culex pipiens and Cx. tarsalis, and has also produced higher viremia levels in the primary amplifying host, the house sparrow. This situation is an excellent example of how selection can simultaneously increase fitness on two different, interrelated hosts (an invertebrate vector and a vertebrate host), explaining the rapid triumph of WN02 on the continent. The virus’s evolution is not a one-sided process; it also involves a mutual arms race with its hosts, reminiscent of the “Red Queen” hypothesis. WNV’s relationship with house sparrows clearly demonstrates this dynamic. As the virus evolves to evade the host immune system and create higher viremia (as seen THE EVOLUTION OF WEST NILE VIRUS AND ITS INTERACTION . . .   77 in the transition from NY99 to WN02/SW03), host populations also develop resistance mechanisms against the virus. This reciprocal interaction creates a powerful ecological pressure that shapes both the virulence of the virus and the demographics of bird populations. On the other hand, the virus’s relationship with its mosquito vector reveals a different equilibrium: the “virulencetransmission trade-off.” The fact that the experimentally evolved MP20 strain, which gained the ability to replicate excessively in mosquitoes, limits its own long-term transmission potential by shortening the vector’s lifespan points to a fundamental constraint that may explain why arbovirus evolution generally follows a slow and steady course. Thus, the success of a virus within a host may not always be directly proportional to its success in spreading between populations. Climate conditions, particularly temperature, determine the stage on which all these biological interactions play out. Temperature is not a simple variable in the WNV transmission cycle, but rather an accelerator. Studies have shown that the relationship between temperature and transmission rate is not linear, but rather exhibits an exponential increase. The fact that the model that best explains transmission includes a term involving the fourth power of temperature is the clearest mathematical expression of this situation. The practical implication is this: even small temperature increases predicted in the context of global warming can cause disproportionately large increases in WNV transmission risk that traditional models may underestimate. More importantly, the superiority of the adapted WN02 genotype over NY99, which becomes even more pronounced at higher temperatures, indicates a worrying synergy between evolutionary adaptation and climate change. A warmer world creates a more favorable environment for the spread of evolutionarily “fitter” virus strains. In conclusion, the West Nile virus is a noteworthy pathogen that maintains its dynamism due to its genetic plasticity, complex ecological interactions, and sensitivity to environmental factors. 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Introduction Vector-borne diseases pose a significant threat to global public health, affecting both developed and developing countries. Arthropods and rodents, for example, play a crucial role in transmitting and spreading pathogens, and mosquitoes are among the most important vectors worldwide (Ocvector, 2023; Sacramento–Yolo Mosquito & Vector Control, 2023). By transmitting arboviruses, bacteria and protozoa, mosquitoes cause severe diseases such as yellow fever, dengue fever, West Nile fever, Chikungunya and malaria. These diseases result in high morbidity and mortality rates (Gould et al., 2003; Tolle, 2009). According to the World Health Organization (WHO), vector-borne diseases account for around 17% of the global infectious disease burden and cause almost 700,000 deaths each year (WHO, 2019). Climate change, urbanisation, environmental degradation and increased human mobility directly influence vector distribution and the spread of pathogens. The positive correlation between rising temperatures and increasing case numbers highlights the potential for vector-borne diseases to pose an even greater threat to global health in the near future (Gould et al., 2009). The prevalence of diseases transmitted by mosquitoes of the genera Aedes, Culex and Anopheles is particularly increasing; for example, approximately 247 88   MODERN RESEARCH AND INVESTIGATIONS IN NATURAL . . . the research by Moreira et al. (2000), the expression occurs throughout the body in Anopheles albimanus larvae and pupae. Following the expression of EGFP via the piggyBac transposon system, which utilises a genetically engineered transposase enzyme to insert a gene into a cell’s genome, the expression was observed (The piggyBac transposon system uses a genetically engineered transposase enzyme to insert a gene into a cell’s genome). As demonstrated in the research by Perera et al. (2002), a green fluorescent protein has been observed in the abdomen of adult specimens. In a separate study, Nolan et al. (2002) modified the expression of dsRED and blue fluorescent proteins in Anopheles stephensi, targeting second and third instar larvae and adult female midguts (dsRED) and adipose tissue (blue), respectively. Figure 3. Transgenesis process: Microinjection of donor and helper plasmids into insect eggs, transfer of the transgene into the germline, and identification of transgenic individuals (Coutinho-Abreu vd., 2010). PARATRANSGENESIS   89 4.1. The Expression of Transgenes is Subject to the Specific Characteristics of the Tissue Concerned In the context of insect vectors, a pathogen may interact with specific tissues, such as the midgut (e.g. for Trypanosoma cruzi and Leishmania sp.) or the haemolymph and salivary glands (e.g. for Plasmodium sp.). The expression of molecules that are capable of inhibiting the development of pathogens within the vector is conducted in a manner that is specific to the tissue, thereby enhancing their efficacy. The expression of a transgene in a specific tissue is achieved by utilising a promoter that is specific to that particular tissue. The majority of promoters employed in the context of vector transgenes are known to direct the expression of proteins in a manner that is specific to the midgut, haemolymph, or salivary glands (Abraham et al., 2005; Kokoza et al., 2000; Lombardo et al., 2005; Moreira et al., 2000; Rodrigues et al., 2008; Yoshida et al., 2006). This is predicated on the understanding that these specific regions are those in which pathogens are most commonly encountered in an infected vector. In the context of mosquito research, the utilisation of carboxypeptidase and peritrophin promoters has emerged as a prevalent approach to achieve the specific expression of transgenes within the midgut. A study published by Moreira et al. (2000) concluded that in Ae. aegypti, the expression of luciferase under the control of the carboxypeptidase promoter was found to be similar to the expression profile detected for the native carboxypeptidase. Furthermore, the study found that expression was only detected in females and after feeding in the midgut (Moreira et al., 2000). As demonstrated in the studies conducted on An. stephensi and Aedes fluviatilis, comparable outcomes were achieved through the utilisation of an An. gambiae peritrophin promoter to regulate the expression of a transgenic protein (Abraham et al., 2005; Rodrigues et al., 2008). In the case of Ae. aegypti, the expression of transgenes in adipose tissue is directed by a vitellogenin promoter. This promoter has been utilised to express genes associated with the innate immune system (Bian et al., 2005; Kokoza et al., 2000) and to express double-stranded RNA (dsRNA) targeting REL1 gene transcripts (Bian et al., 2005). As demonstrated in the study by Nirmala et al. (2006), the same promoter has also been used to ensure Fl expression of CFP in An. stephensi. The robustness of the vitellogenin promoter has been confirmed by its ability to function after multiple gonotrophic cycles in transgenic An. stephensi (Chen et al., 2007). Salivary gland-specific promoters have also been used in germline transformation of mosquitoes (the process of altering an organism’s genetic makeup by adding a new gene to its genome). The D7 90   MODERN RESEARCH AND INVESTIGATIONS IN NATURAL . . . and apiraz promoters from An. gambiae and the antiplatelet promoter from An. stephensi were utilised in the transformation of An. stephensi (Lombardo et al., 2005; Yoshida et al., 2006). Transgenesis was performed in Ae. aegypti using maltase-like (Maltase-like1) and apiraz promoters, with luciferase successfully expressed in the salivary glands of Ae. aegypti (Coates et al., 1999). 5. Paratransgenesis Paratransgenesis is defined as the use of genetically modified symbiotic bacteria that express molecules capable of inhibiting pathogen development or transmission via vectors (Coutinho-Abreu et al., 2010). The objective of this research is to reduce vector competence by genetically modifying symbionts. Transgenic symbionts have been observed to disseminate throughout an insect population by either maternal inheritance or via coprophagy (Durvasula et al., 1997). This modification results in the production of specific targeted immune effectors (antibody-producing plasma cells). These bacteria can act by reducing the vector’s fertility or fecundity, or by inhibiting the vector’s competence. Consequently, the capacity of vectors to transmit diseases can be diminished or eradicated (Wilke et al., 2015). One symbiotic bacterium to which this method has been applied is Pantoea agglomerans, a member of the midgut flora genetically engineered to produce two anti-malaria proteins in the Anopheles gambiae mosquito. Pantoea agglomerans is an ideal candidate for expressing these effective proteins because it multiplies rapidly after feeding on blood and, particularly after consuming an infected meal, shares the same environment as the malaria parasite. The expression of these anti-malaria peptides in mosquitoes has been shown to result in a 98% reduction in Plasmodium development and an 84% reduction in the number of mosquitoes carrying the malaria parasite. P. agglomerans is regarded as a potentially efficacious agent in the management of vector-borne diseases (Wang et al., 2012). Another symbiotic bacterium employed in the paratransgenic approach is the Gram-negative Asaia sp., which has also been used in the secretion of antimalarial peptides, resulting in a substantial reduction in parasite development (80.1%). In comparison with P. agglomerans, Asaia sp. exhibits superior proliferation within the mosquito population, with a longer duration of multiplication. Furthermore, Asaia sp. has been found to be present not only in the midgut but also in the salivary glands and reproductive organs, which play an important role in disease transmission (Bongio et al., 2015). PARATRANSGENESIS   91 Symbiotic densoviruses have the capacity for genetic manipulation, through which it is possible to express molecules that reduce vector competence. Densoviruses are a category of viruses that are characterised by their linear, single-stranded DNA configuration. The genome of a densovirus is packaged within an enveloped particle. These viruses are considered to be effective vectors for the expression of foreign genes in mosquitoes due to their high specificity, environmental stability, ability to kill mosquito larvae in a dose-dependent manner, reduction of the lifespan of surviving adults, and vertical transmission (Carlson et al., 2006). In Ae. aegypti, densoviruses have been observed to disseminate to the fat body, muscles, and nerves following infection via the canal papilla (Ward et al., 2001). Densoviruses infecting Ae. aegypti (AeDNV) and An. gambiae (AgDNV) have been isolated and modified to express green fluorescent protein (Ren et al., 2008; Ward et al., 2001). The phenotype obtained by the expression of green fluorescent protein (GFP) in recombinant AgDNV infecting An. gambiae was observed in 20% of the F2 and F3 generations. This suggests that transgenic densoviruses could be used to express molecules targeting the development of pathogens in mosquitoes (Coutinho-Abreu et al., 2010). Figure 4. Example of application of a paratransgenesis based-approach for the control of mosquito vector competence. Engineered symbionts colonize midgut and reproductive organs of Anopheles gambiae mosquitoes and express anti-pathogen effector molecules, leading to the inhibition of Plasmodium parasite development (Gabrieli et al., 2021). 92   MODERN RESEARCH AND INVESTIGATIONS IN NATURAL . . . Despite the evident promise of paratransgenesis as a means of controlling vector-borne diseases, it is imperative that certain challenges are addressed. For instance, the impact of commensal bacteria may be subject to variation depending on the type of pathogen transmitted and the specific mosquito species involved. While Serratia has been observed to have an anti-plasmodial effect in Anopheles, it may promote the transmission of the dengue virus in Culex spp. mosquitoes. A further limitation is that Wolbachia must be capable of successful reproduction within mosquitoes while concurrently preventing pathogen infection. Consequently, the identification of an Anopheline-derived symbiont capable of reducing disease transmission remains a significant objective (Huang et al., 2020). 5.1. The Wolbachia Approach It is widely acknowledged that Wolbachia represents a highly intriguing microorganism in the context of arthropods. This particular microbe has the capacity to exert a significant influence on the reproductive biology, metabolism, and immune system of its arthropod hosts (Werren et al., 2008). The first identification of these obligate intracellular bacteria was by Hertig and Wolbach in the mosquito Culex pipiens (Hertig et al., 1924). Although Wolbachia has been identified in numerous insect species and populations, its distribution is patchy (Hilgenboecker et al., 2008). As demonstrated in the study by Ding et al. (2020), the presence of the virus has been observed in the reproductive organs and somatic tissues of various species of mosquitoes, including those belonging to the genera Culex, Aedes, Coquillettidia, Mansonia, and Uranotaenia. The presence of these bacteria has been shown to cause reproductive changes, including parthenogenesis and sex ratio distortions, in cases where genetically male individuals are infected with the Wolbachia strain. This results in the modification of the sperm, leading to the death of embryos during the early embryonic development stage. Cytoplasmic incompatibility has been demonstrated to confer a reproductive advantage to Wolbachia-infected females over uninfected ones, leading to the rapid spread of Wolbachia (Jiggins, 2017). The presence of Wolbachia has recently been detected in Ae. aegypti and certain Anopheles mosquito species; however, its prevalence may vary between species (Balaji et al., 2019; Baldini et al., 2014). With regard to the presence of Wolbachia in Anopheles mosquitoes, studies have demonstrated a negative correlation between Wolbachia infection in An. gambiae and Plasmodium, suggesting that Wolbachia may reduce malaria PARATRANSGENESIS   93 transmission through its impact on sporozoites (Gomes et al., 2017; Shaw et al., 2016). However, evidence of Wolbachia infection in Anopheles mosquitoes has generally been concentrated at the molecular level, meaning that detecting active Wolbachia infections is not always straightforward (Chrostek et al., 2019; Ross et al., 2020). The limited presence of Wolbachia in some Anopheles mosquitoes may be due to the prominent role played by Asaia bacteria in these mosquitoes (Chouaia et al., 2012; Favia et al., 2007). Indeed, it has been demonstrated that Asaia symbionts interfere with the vertical transmission of Wolbachia and exhibit a negative correlation with Wolbachia in mosquito reproductive tissues (Hughes et al., 2014; Rossi et al., 2015). Prior to the observation of naturally infected individuals of Ae. aegypti, stable and heritable Wolbachia infections were established in laboratory colonies of this species through embryonic microinjection of Wolbachia from donor species (Xi et al., 2005). As demonstrated in the relevant literature (see Hoffmann et al., 2011; Nazni et al., 2019; Xi et al., 2005), Wolbachia is known to spread to wild Ae. aegypti populations via the cytoplasmic incompatibility mechanism following the release of infected mosquitoes. Furthermore, Wolbachia has been stably introduced into an An. stephensi colony, thereby enhancing the bacteria’s host resistance against P. falciparum (Bian et al., 2013). This phenomenon has also been observed in Ae. aegypti (Aliota et al., 2016; Bian et al., 2010; Hussain et al., 2013; Kambris et al., 2009; Moreira et al., 2009). In the absence of Wolbachia, it is generally accepted that the infection of insects with symbionts should trigger an immune response, resulting in the elimination of Wolbachia. However, Wolbachia have been shown to circumvent this process by evading antimicrobial peptide (AMP)-based immune responses or suppressing autophagy-related immune defences (Zug et al., 2015). Conversely, the principle of natural selection may provide a rationale for the bacterium’s persistence, contingent upon the assertion that Wolbachia confers a selective advantage that enhances the host’s fitness (Brownlie et al., 2009; Gerth et al., 2016). However, it is anticipated that, over time, Wolbachia’s immunestimulating properties will diminish, leading to a stabilisation of the association. Furthermore, the infection of Aedes mosquitoes with Wolbachia has been shown to affect the abundance of resident bacteria without impacting species diversity (Audsley et al., 2018). It is noteworthy that a number of bacterial species within Anopheles mosquitoes exhibit a negative correlation with Wolbachia. For instance, the 94   MODERN RESEARCH AND INVESTIGATIONS IN NATURAL . . . indigenous mosquito microbiota, notably comprising bacteria of the genus Asaia, has been demonstrated to impede Wolbachia infection (Hughes et al., 2014; Rossi et al., 2015). Therefore, given Wolbachia’s variable effect on the composition of the mosquito microbiota, it is crucial to understand these factors before transinfecting Wolbachia into a new mosquito species for pathogen control. As posited by Muturi et al. (2016, 2017) and Straub et al. (2020), this necessitates an appreciation of factors such as host species, developmental stage and sampling location. Figure 5. Simplified theme of the Wolbachia method (Sarwar et al., 2022) 6. Prospective Trends The success of transgenesis in insect vector symbionts raises questions regarding the replacement of non-transgenic symbionts in natural insect populations and the potential impact on pathogen development and transmission in natural habitats. It is acknowledged that symbionts do not impose any fitness burden on insect hosts and can be transmitted either vertically (via transovarial transmission) or horizontally (due to feeding habits). Consequently, the development of a robust gene drive system is imperative to augment the efficacy of paratransgenesis. The hypothesis that Wolbachia endosymbionts could serve as a gene drive system has been proposed. (Aksoy et al., n.d.) Wolbachia are intracellular, maternally inherited bacteria that manipulate insect reproductive biology through cytoplasmic incompatibility (Sinkins et al., PARATRANSGENESIS   95 2006). It has been demonstrated that cytoplasmic incompatibility is responsible for the fact that a female insect which is not infected with Wolbachia cannot reproduce with an infected male. This phenomenon results in a reduction in the frequency of uninfected individuals, whilst concomitantly increasing the frequency of Wolbachia-infected insects within a given population. Consequently, the dissemination of other maternally inherited transformed symbionts within an insect population with Wolbachia (Aksoy et al., n.d.) is expected to increase the frequency of the transformed symbiont. This mechanism has been observed in species such as Ae. aegypti, Aedes albopictus, and Culex quinquefasciatus, and it offers a potential route for the spread of transformed symbionts, such as densoviruses, in natural mosquito populations (Sinkins et al., 2006). A recent study (Jin et al., 2009; McMeniman et al., 2009) has identified a strain of Wolbachia (wMelPop) in Drosophila melanogaster that has been shown to shorten the lifespan of the organism. This strain has since been utilised in Ae. aegypti and An. gambiae. The Wolbachia strain has been demonstrated to facilitate the propagation of the transgenic symbiont across the mosquito population. Concurrently, it has been shown to curtail the duration during which pathogens can develop within the mosquito, a process referred to as the external incubation period (EIP). (McMeniman et al., 2009). However, a potential application of Wolbachia identified in D. melanogaster may face a significant disadvantage, in that this approach may be associated with the pathogen’s ability to overcome the reduced vector lifespan for its own development (Read et al., 2009). Consequently, the efficacy of this type of selective pressure in eradicating disease vectors in Anopheles remains uncertain. It is imperative that an optimal approach is implemented in order to reduce both vector competence (linear parameter) and vector survival time (exponential parameter). The combination of these two effects has been demonstrated to result in a substantial reduction in vector capacity and disease burden within endemic regions. The hypothesis that a genetically modified densovirus capable of inhibiting pathogen development, when administered in conjunction with a symbiont such as wMelPop, could potentially serve as a double-barrier mechanism to prevent transmission, has been put forward (Coutinho-Abreu et al., 2010). 7. Conclusion Vector-borne diseases continue to pose a significant global health burden, causing hundreds of thousands of deaths annually and disproportionately affecting populations in tropical and subtropical regions (World Health Organization, 96   MODERN RESEARCH AND INVESTIGATIONS IN NATURAL . . . 2019; World Health Organization, 2023b). Conventional approaches to vector control, encompassing environmental management, mechanical interventions, biological regulation, and chemical applications, have historically constituted integral components of public health strategies. However, the emergence of insecticide resistance and concerns regarding ecological sustainability have highlighted the limitations of relying solely on conventional methods (Hill et al., 2005; Garske et al., 2014). Biotechnological innovations have emerged as a promising alternative to complement and strengthen existing vector control programmes. Transgenesis and paratransgenesis have demonstrated the capacity to impede the development of pathogens within vectors, thereby reducing their transmission potential (Ito et al., 2002; Moreira et al., 2000; Coutinho-Abreu et al., 2010). In a similar vein, the deployment of Wolbachia has demonstrated promise in curtailing the vectorial capacity of mosquitoes, either by diminishing their lifespan or by directly impeding pathogen replication (Gabrieli et al., 2021). While these approaches hold great promise, their successful implementation is dependent on the successful overcoming of challenges related to ecological interactions, scalability, public acceptance, and long-term sustainability. In the future, the most effective strategy for controlling vector-borne diseases will likely involve an integrated framework that combines classical approaches with innovative biotechnological tools. Such integration has the potential to reduce disease transmission and to support global health systems in achieving sustainable and environmentally responsible outcomes. 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Introduction Mathematics education, as a discipline grounded in deep philosophical foundations concerning nature, source, and acquisition of knowledge, has played a fundamental role in individual cognitive development and the advancement of societies’ scientific and cultural progress. In this respect, mathematics education has undergone continuous evolution throughout history, reflecting the educational philosophies of various eras. From the perspective of educational philosophy, mathematics is defined not merely as numerical operations but as a domain of mental skills that systematically cultivates logical reasoning, abstract thinking, and problem-solving processes (Ernest, 1991; Skemp, 1976). Therefore, mathematics education is not only about the transmission of knowledge but also a complex process that aims at transforming the learner’s cognitive structure and epistemological competence (Sfard, 1991). Throughout history, mathematical knowledge has been shaped by the sociocultural needs of various civilizations, and educational models have diversified within this framework. The arithmetic and geometric methods developed by 108   MODERN RESEARCH AND INVESTIGATIONS IN NATURAL . . . early civilizations such as Mesopotamia and Egypt were primarily oriented toward practical and administrative purposes (Katz, 2009). In contrast, ancient Greek philosophers approached mathematics within the context of epistemology and ontology, engaging in theoretical discussions on the nature, truth, and certainty of mathematics (Heath, 1956). Euclid’s Elements is considered the first systematic example of the pedagogical applicability of axiomatic systems and mathematical logic, and it remains a fundamental reference in modern mathematics education (Euclid, ca. 300 BCE/1956). During the Middle Ages, mathematics education in Western Europe was largely symbolic and theoretical, confined within church-centered scholastic institutions (Fauvel et al., 2006). Meanwhile, in Islamic civilization, mathematical studies progressed in parallel with the development of scientific methodology; mathematicians such as Al-Khwarizmi introduced the concepts of algebra and algorithm, transforming the nature of mathematics education (Berggren, 2016). In this period, mathematics education gained an interdisciplinary character across both theoretical and applied fields, forming the foundation of scientific advancement (Rashed, 1994, pp.432-451). In the Renaissance and Enlightenment periods, mathematics education began to be taught systematically in academic institutions under the influence of positivist and rationalist philosophy. Educational curricula were restructured, and the epistemic and pedagogical dimensions of mathematical thinking were addressed more consciously (Kline, 1972). In the 19th and 20th centuries, developments in educational psychology and pedagogical methods led to the adoption of more constructivist and student-centered approaches in mathematics education (Piaget, 1952; Vygotsky, 1978). In Turkey, mathematics education began to transform within the context of modernization efforts of the Ottoman Empire, laying the groundwork for contemporary educational systems. With the reforms introduced during the Republican era, secular and scientific approaches became the foundation of education; a modern structure of mathematics teaching was established, integrated with Western models (Akdeniz, 2011). Today, the integration of digital technologies and information-communication tools into educational processes has given rise to new paradigms in mathematics education (Borba & Villarreal, 2005). This study aims to examine the historical development of mathematics education through a multidimensional and interdisciplinary perspective, revealing the epistemic heritage and pedagogical approaches of different THE HISTORICAL DEVELOPMENT OF MATHEMATICS EDUCATION . . .   109 cultures. With a particular focus on Turkey, the study will provide an in-depth analysis of the cultural transformation of mathematics education and establish a scientific foundation for future educational policies. 2. Mathematics Education in Antiquity 2.1 Egypt and Mesopotamia The historical roots of mathematics education date back to the earliest civilizations in human history. In particular, the civilizations of Mesopotamia and Egypt stand out as among the first cultures to systematically develop and teach mathematical knowledge. The mathematical accumulation of these two civilizations formed a foundational basis for their time and subsequent cultures. In this section, the structure of mathematics education in Mesopotamia and Egypt, its fields of application, the number systems used, and educational tools will be discussed from a historical and academic perspective. 2.1.1 Mathematics Education in Mesopotamia Mesopotamia emerged as a significant center of mathematical education from around 3000 BCE. In this region, inhabited by diverse peoples such as the Sumerians, Akkadians, Babylonians, and Assyrians, mathematics was developed primarily for practical purposes in daily life (Robson, 2008). Mesopotamian mathematics is especially documented through numerical data and operations inscribed on clay tablets. These tablets served as educational materials used to learn and apply arithmetic knowledge needed in administrative and commercial activities (Neugebauer, 1969). The sexagesimal (base-60) number system developed by Babylonian mathematicians is one of the most remarkable features of Mesopotamian mathematics. This system proved highly effective in astronomical calculations and provided a solid foundation for solving complex mathematical problems (Friberg, 2005). Its flexibility made it particularly suitable for calculating angles, measuring time, and determining areas of circles (Høyrup, 2016). Thus, mathematical knowledge was taught and used both theoretically and practically in a systematic way (Høyrup, 2016). The Mesopotamian education system was organized around temples and palace centers. Students were educated in scribal schools, where they learned cuneiform writing techniques and received extensive training in computational methods (Robson, 2008). The curriculum typically focused on calculation, 110   MODERN RESEARCH AND INVESTIGATIONS IN NATURAL . . . listing, solving algebraic problems, and understanding geometric figures. Area and volume calculations were critically important for land measurement and engineering applications (Neugebauer, 1969; Robson, 2008). The foundation of this educational model lay in the direct connection between mathematical knowledge and the needs of daily life. Mesopotamian mathematics later contributed significantly to Greek and Islamic sciences, especially laying the groundwork for algebraic and astronomical studies (Smith, 1951). 2.1.2 Mathematics Education in Egypt In contrast to Mesopotamia, mathematics education in ancient Egypt was more applied and closely linked to everyday life. Starting from around 3000 BCE, the need to redefine land boundaries due to the annual flooding of the Nile River played a central role in the development of geometric knowledge and calculations (Karp, 2012). Together with the hieroglyphic writing system, mathematical knowledge was recorded on papyri and stone carvings. Education took place in temples and the royal court, mainly targeting future civil servants and engineers (Chace, 1927). Egyptian mathematics was used extensively in area and volume calculations, civil engineering, and taxation. Consequently, the focus of education was on developing practical mathematical skills. For example, documents like the Rhind Papyrus and the Moscow Papyrus served as educational materials containing mathematical problems and their solutions, through which students were expected to gain proficiency (Molland, 1991). These documents included basic arithmetic operations—addition, subtraction, multiplication, and division—as well as fractions, ratios, and area calculations in detail (Chace, 1927). The regular flooding of the Nile, which constantly altered land boundaries, served as a key motivation for the practical use of geometric knowledge. In Egypt, mathematics education was closely associated with engineering and architectural projects; geometric knowledge played a critical role in the construction of complex structures such as pyramids. Hence, mathematics education is aimed at acquiring both technical and applied knowledge. The materials used in the educational process reached a limited number of students due to the complexity of hieroglyphic writing and the exclusivity of education. Nevertheless, mathematical knowledge was considered a mark of prestige, particularly in the realms of administration and engineering, and experts in the field enjoyed high social status (Chace, 1927). THE HISTORICAL DEVELOPMENT OF MATHEMATICS EDUCATION . . .   111 2.1.3 Academic Assessment Although shaped by the unique needs of different societies, mathematics education in Mesopotamia and Egypt shared a common foundation: the integration of mathematics as both a science and a practical tool. While more abstract number systems and astronomical applications were prominent in Mesopotamia, Egypt emphasized applied mathematics such as geometry and area calculations. The mathematical education models of these civilizations later served as crucial sources for both Greek mathematics and the scientific advancements in the Islamic world. The analysis of educational materials, teaching methods, and mathematical problems is indispensable for understanding the historical evolution of mathematics (Robson, 2008). In conclusion, mathematics education in Mesopotamia and Egypt, shaped by both cultural and technological developments, presented the earliest systematic examples of acquiring and applying mathematical knowledge. 112   MODERN RESEARCH AND INVESTIGATIONS IN NATURAL . . . Table 2.1 Comparison of Mathematics Education in Mesopotamia and Egypt Feature Mesopotamia Egypt Historical Period From around 3000 BCE From around 3000 BCE Educational Centers Temples and palaces; scribal schools Temples and royal court; training for civil servants and engineering candidates Number System Sexagesimal (base-60) number system Decimal system; hieroglyphic script Mathematical Focus Arithmetic, algebra, geometry, and astronomical calculations Applied geometry, area, volume calculations, and engineering applications Educational Materials Clay tablets, numerical data, and exercises Papyri (e.g., Rhind and Moscow Papyri), stone reliefs Educational Content Calculations, lists, algebraic problems, geometric understanding Basic arithmetic operations, fractions, ratios, land measurement, and constructionrelated problems Practical Applications Administration, trade, astronomy, land surveying, engineering Land measurement after Nile floods, construction (pyramids), tax collection, engineering Access to Education Scribes and administrators, cuneiform schools Limited, civil servants and engineering candidates; complex hieroglyphic writing Social Status of Mathematics Experts Respected experts in administration and astronomy High social status in administration and engineering Legacy Influenced Greek and Islamic mathematics, especially algebra and astronomy Contributed to later civilizations in geometry and applied mathematics Table 2.1 summarizes the main mathematical methods and areas of application used in Mesopotamian civilization. Arithmetic operations were recorded on clay tablets for use in daily administrative and commercial activities, particularly including calculations involving proportions and interest. Geometric computations were based on area and volume measurements, especially for the THE HISTORICAL DEVELOPMENT OF MATHEMATICS EDUCATION . . .   113 planning of temples and other architectural structures. Through these methods, Mesopotamian mathematics developed for both theoretical and practical purposes and was systematically documented in written records. 3. Mathematics Education in the Middle Ages and the Islamic World 3.1 Western Europe During the Middle Ages, the education system in Western Europe was largely shaped under the authority of the Church. The curriculum, considered the foundation of education during this period, was divided into two main parts: the Trivium and the Quadrivium. While the Trivium included grammar, rhetoric, and logic, the Quadrivium consisted of arithmetic, geometry, astronomy, and music (Lindberg, 2007). Although mathematics was part of the Quadrivium, the perception of education primarily as a tool to support religious dogma limited the development of practical and experimental aspects of mathematics. Cathedral schools and the universities that evolved from them (such as the University of Paris and the University of Bologna) continued to teach mathematics throughout the Middle Ages (Dreyer, 1953). However, mathematical instruction in these institutions was largely conducted through commentaries on the works of Plato and Aristotle, thus confining mathematics to a theoretical and abstract domain. This approach hindered the advancement of scientific methods and the practical applications of mathematics. Particularly in the 12th century, translations from Arabic into Latin facilitated the acquisition of new mathematical knowledge; Euclid’s Elements and the works of Arab mathematicians became essential sources of learning during this period (Grant, 1996). Nevertheless, mathematical thought remained strongly tied to religious and philosophical doctrines. Throughout the Middle Ages, mathematics education remained part of the Church’s curriculum and served theological purposes rather than promoting scientific progress (Saliba, 1994). However, significant progress in mathematics began to accelerate during the Italian Renaissance of the 14th and 15th centuries. The work of Leonardo Fibonacci, the spread of the decimal number system, and developments in algebra contributed to the integration of mathematics into everyday life (Rashed, 1994, pp. 123–142). Yet, such advancements were limited before the Renaissance, and mathematics education throughout the Middle Ages remained largely confined to institutional and dogmatic structures. 120   MODERN RESEARCH AND INVESTIGATIONS IN NATURAL . . . mathematical knowledge (Eisenstein, 1979). The abacus schools of Renaissance Italy were among the first practical reflections of this dissemination; Luca Pacioli’s printed textbook Summa de Arithmetica (1494), by presenting arithmetic and algebra in Italian instead of Latin, popularized computational skills among the merchant class (Pacioli, 1494). The 17th century marked the synthesis between algebra and geometry through René Descartes’s La Géométrie (1637), while Pierre de Fermat made significant contributions to analytic geometry and number theory, which began to be incorporated into university curricula (Britannica, n.d.; Descartes, 1637). The rise of analytical methods in this era supported the development of rational and systematic teaching approaches reinforced by empirical observations. During the Enlightenment (18th century), universities moved away from ecclesiastical control and became stateand academically oriented institutions. In centers like Berlin and Göttingen, the Humboldt model positioned mathematics as a central component of the building ideal (Humboldt Model, n.d.). In France, Gaspard Monge’s integration of descriptive geometry into the École Polytechnique curriculum is considered a prototype for engineering-based applied mathematics education (Britannica, n.d.-b; Monge Reform, n.d.). Table 4.2 Key Developments in Mathematics Education During the Renaissance and Enlightenment Period Significant Developments Impacts on Education 15th Century (Invention of the Printing Press) Gutenberg’s printing press increased the reproduction speed of scientific texts; Luca Pacioli’s Summa de Arithmetica popularized arithmetic and algebra in the vernacular (Pacioli, 1494). Mathematical knowledge spread rapidly geographically and socially; computational skills improved among commercial classes 17th Century (Analytic Geometry) Descartes’ synthesis of algebra and geometry in La Géométrie; Fermat’s contributions to analytic geometry and number theory Analytical methods were introduced into university curricula, rational and empiricalbased teaching approaches have been developed. 18th Century (Enlightenment) Mathematics became part of the Bildung ideal through the Humboldt model; Monge integrated descriptive geometry into the École Polytechnique curriculum. Universities became independent from church control; applied mathematics and engineeringfocused education programs advanced. THE HISTORICAL DEVELOPMENT OF MATHEMATICS EDUCATION . . .   121 Table 4.2 summarizes the evolution of mathematics education in the 15th, 17th, and 18th centuries. The invention of the printing press accelerated the dissemination of scientific and mathematical knowledge, spreading computational skills among commercial classes. In the 17th century, the works of Descartes and Fermat brought analytic geometry and number theory into university curricula, strengthening the teaching of analytical and experimental methods. During the Enlightenment, Humboldt’s educational model and Monge’s applied mathematics reforms made mathematics education independent from the church, transforming it into a more systematic, state-supported, and engineering-oriented discipline. 4.2 Modern Mathematics Education in the 19th and 20th Centuries 4.2.1 Comprehensive Transformation of Mathematics Education During the Industrial Revolution and the Modern Era According to Preveraud (2021), the 19th century witnessed a significant transformation in the French education system, particularly through the expansion of state control and the gradual secularization of curricula. These reforms aimed to promote a rational, centralized model of education, in which mathematics played a key role as a tool for developing disciplined, scientifically minded citizens. The teaching of mathematics thus became not only a pedagogical goal but also a political and ideological strategy aligned with Enlightenment values. Beyond the French context, from the 1840s onward, English technical colleges (mechanics’ institutes) and French écoles d’arts et métiers began focusing on practical problem solving under the name of “applied mathematics.” In Germany, the wave of systematic abstraction emerging towards the end of the 19th century, Georg Cantor’s set theory, and David Hilbert’s axiomatic program radically transformed university curricula by prioritizing the teaching of abstract concepts over computational skills. This approach quickly spread to Scandinavia and Russia through the Göttingen school, which emerged as a leading center of mathematical thought and research. In the Soviet Union, radical programs were implemented between the 1920s and 1930s; from the 1950s onwards, “mathematics schools,” Olympiad schools, and the talent-tracking model pioneered by the Steklov Institute emerged. Thus, the algebra–topology–analysis triad was introduced at the pre-undergraduate level, and a research-oriented high school curriculum was developed (İnalcık, 2006; Karpat, 1979; Karp, 2012; Topuz, 2007). 122   MODERN RESEARCH AND INVESTIGATIONS IN NATURAL . . . During the same period in the United States, following World War II, applied mathematics based on engineering and computation rose with the support of the GI Bill and NSF scholarships, while Bourbaki’s abstract approach triggered “modern mathematics” reforms in Western Europe. The “New Math” movement of the 1960s brought sets, logic, and algebraic structures into high school textbooks but was withdrawn in the 1970s. Nevertheless, differential equations, probability theory, and statistics became standard content for the last year of high school and the first year of university. Table 4.3 Key Stages of Mathematics Education from the Industrial Revolution to the Cold War Period / Region Main Developments Impacts on Education 19th Century Industrial Revolution (Britain, France) Technical colleges; écoles d’arts et métiers; engineering-focused problems; introduction of differential equations and statistics into secondary education Practice-oriented teaching of mathematics; mandatory applied courses; “public arithmetic” for commercial and industrial classes Late 19th/Early 20th Century Germany Cantor’s set theory; Hilbert’s axiomatic method; Göttingen school Principle of “abstraction”: Conceptual proof, axiomatic approach, and strengthening of pure mathematics as a separate discipline 1920–1960 Soviet Union Radical school reforms, mathematics high schools, Olympiad system, Steklov Institute Research culture before undergraduate level; early teaching of algebra, topology, and analysis trio; tradition of problem solving 1945–1970 USA and Western Europe GI Bill, NSF funding; computer revolution; “New Math” reform inspired by Bourbaki Rise of applied mathematics (computing, statistics); sets and logic introduced into high school curriculum; modernization of teacher education Table 4.3 summarizes the transformation of mathematics education into four main stages from the Industrial Revolution to the post-Cold War era. THE HISTORICAL DEVELOPMENT OF MATHEMATICS EDUCATION . . .   123 In the first stage, technical requirements led to the widespread inclusion of applied courses in secondary education. In the second stage, the abstraction movement in Germany made university mathematics programs theory-centered. In the third stage, the Soviet model’s problem-solving and research-oriented approach extended down to high school, creating a global impact through international Olympiads. In the fourth stage, the demands of the computer and defense industries in the United States and Western Europe brought statistics and computation to the forefront, while Bourbaki’s abstract vision infiltrated the high school curriculum; however, the “New Math” reform remained limited. This chronological evolution explains why contemporary curricula require a balance between abstract conceptual depth and applied problem-solving. 4.2.2 Digitalization and Mathematics Education in the 21st Century The widespread adoption of computers and the internet has moved learning environments to synchronous/asynchronous online platforms (Bruff, 2019). The emergence of the discipline of learning analytics provided a conceptual framework for the use of big data in instructional design (Siemens, 2013; Downes, 2012; Choi, 2021). Artificial intelligence-supported personalized systems update student models in real time and suggest individual learning paths; the report by Luckin and Holmes discusses the pedagogical and ethical dimensions of this transformation in detail (Britannica, n.d.-a; Luckin & Holmes, 2016). During the global COVID-19 crisis, emergency remote teaching practices revealed issues of the digital divide and accessibility (Britannica, n.d.-a.; Humboldt Model, n.d.); the OECD’s “Students, Computers and Learning” report presented a datadriven analysis of the complex relationship between cognitive gains and the use of technology (Monge Reform, n.d.; OECD, 2015). These findings highlight the necessity of sustainable and inclusive digital strategies in 21st-century mathematics education policies. In recent years, massive open online courses (MOOCs), flipped classrooms, and augmented/mixed reality (AR/VR) applications have deepened conceptual understanding by visualizing abstract mathematical concepts (Encyclopedia Britannica, n.d.; Preveraud, 2021). Blockchain-based certification systems enable the reliable documentation of micro-learning units, thus expanding the lifelong learning ecosystem. On the other hand, the transparency and data privacy of AI-supported assessment tools require new ethical frameworks. 124   MODERN RESEARCH AND INVESTIGATIONS IN NATURAL . . . Table 4.4 Key Developments in Mathematics Education in the Digital Age Technology/ Approach Main Features Impacts on Mathematics Education Online Platforms Synchronous/asynchronous courses, video conferencing, interactive content Time and location independent access, global student reach, and reducing disparities in teacher quality Learning Analytics Big data, dashboards, predictive models Real-time monitoring of student performance, personalized feedback, and early intervention AI-Supported Systems Adaptive content, natural language processing, and automated assessment Personalized learning paths: reducing teachers’ routine assessment workload MOOCs and Micro-Learning Open-access courses, certificate modules Lifelong learning, low-cost access, and development of self-directed study skills AR/VR Applications 3D visualization, interactive simulations Concretizing abstract concepts, enhancing spatial reasoning, and intuitive understanding Blockchain Certification Distributed verification, immutable records Reliability of micro credentials; transparency of skills in the labor market Table 4.4 summarizes the main innovations brought by the digital age to the mathematics education ecosystem. While online platforms and MOOCs democratize access, learning analytics and artificial intelligence offer personalized content and early feedback opportunities. AR/VR applications reinforce abstract concepts through visual-kinesthetic experiences, while blockchain certification strengthens the formal recognition of lifelong learning. However, the effective and equitable use of these technologies depends on reducing the digital divide, safeguarding data privacy, and clarifying pedagogical and ethical principles. 5. Historical Development of Mathematics Education in Turkey 5.1 The Ottoman Period Mathematics education in the Ottoman Empire was concentrated in traditional educational institutions known as madrasahs. Although this model of THE HISTORICAL DEVELOPMENT OF MATHEMATICS EDUCATION . . .   125 education was religiously based, it also included mathematical knowledge due to practical needs. Especially in fields such as astronomy, calendar calculations, waqf administration, and trade, mathematical knowledge was important. The madrasah curriculum included subjects such as Arabic, Persian, logic, and Islamic jurisprudence, alongside basic arithmetic and geometric concepts (Acar, 2012; Akşit, 1991; Ertem, 2010; İnalcık, 2006; İhsanoğlu, 1993; Karpat, 1979; Özdemir, 2004; Topuz, 2007). A more systematic and scientific advancement in mathematics education became possible with the reflection of scientific developments that began in Europe in the 18th century onto Ottoman lands. In this process, especially for military needs, accelerated mathematics education is required. Scientific works and teaching methods from Europe began to be implemented in institutions such as the Tophane School (1735) and the Imperial School of Naval Engineering (Mühendishane-i Bahr-i Hümayun, 1773). These schools marked a turning point in mathematics education in the Ottoman Empire as the first military and engineering schools equipped with modern technical knowledge (Gürbüz, 2015; Kaptan, 2009). At the Tophane School, mathematical knowledge required in artillery and engineering was taught systematically, while the Imperial School of Naval Engineering provided education in mathematical navigation and map-making in the field of maritime studies. Courses such as algebra, trigonometry, geometry, mechanics, and astronomy were taught in these institutions. Additionally, the translation of French and Latin educational materials facilitated access to the European mathematical literature. In the second half of the 19th century, with the Tanzimat reforms and the Second Constitutional Era, Westernization policies in education accelerated. The opening of the Darülmuallimin (Teacher Training School) was important for the training of modern educational staff. Moreover, mathematics courses began to be addressed at a more academic level in the Darülfünun (the precursor of the university) institution, which was established in 1869. During this period, mathematics education was developed and modernized, particularly for use in engineering, medicine, and the natural sciences. However, access to education remained limited, targeting primarily the elite and military classes. Classical education in the madrasahs continued for a long time, and mathematics education remained limited to practical applications. As a result, mathematics education during the Ottoman period was shaped around two different axes: traditional madrasah education and military-technical 126   MODERN RESEARCH AND INVESTIGATIONS IN NATURAL . . . schools aimed at modernization. There were occasional disconnections between these two systems, but from the 19th century onward, modern mathematics education became an increasingly prominent part of the Ottoman education system. Table 5.1 Periodical Evolution of Mathematics Education in the Ottoman Empire Period Educational and Institutional Characteristics Classical Madrasah Period (14th–17th centuries) Mathematics was taught in madrasahs with limited practical knowledge in arithmetic, geometry, and astronomy. Military Modernization (18th century) Technical schools such as the Tophane School (1735) and the Imperial School of Naval Engineering (1773) were established; algebra, trigonometry, and mechanics were taught. Scientific Transfer Period (late 18th – early 19th century) European mathematical literature was translated into Turkish; modern engineering education became widespread. Tanzimat Reforms (1839–1876) Civil schools in the Western style increased. The Darülmuallimin (Teacher Training School) was opened; mathematics education expanded beyond the military domain. Late Ottoman and Constitutional Era (1876–1923) Academic mathematics courses began at the Darülfünun, the divide between modern and traditional education continued. Table 5.1 summarizes the periodical development of mathematics education in the Ottoman Empire. While education initially continued in madrasahs with limited practical knowledge, it modernized with technical and military schools starting from the 18th century; integration into civil education began with the Tanzimat reforms of the 19th century. However, the distinction between modern and traditional education systems remained pronounced. 5.2 Mathematics Education in the Republican Era With the establishment of the Republic of Turkey, comprehensive reforms were carried out in the field of education. The Law on the Unification of Education (Tevhid-i Tedrisat), enacted in 1924, placed all educational institutions THE HISTORICAL DEVELOPMENT OF MATHEMATICS EDUCATION . . .   127 under state supervision and adopted the principles of secular and contemporary education. These reforms aimed to unify the fragmented educational system inherited from the Ottoman era under a single framework and to promote a modern understanding of education. Mathematics education was systematically restructured during this period. Curricula were developed for all educational levels, from primary to higher education, and the fundamental concepts of mathematics, along with problemsolving skills, were adopted as primary objectives. Arithmetic and geometry were emphasized in primary education, while algebra, calculus, trigonometry, and geometry were taught more in-depth at the secondary level (Akkan, 2013; Demir, 2020; Özer, 2018). Teacher training institutions played a significant role in the development of mathematics education during the Republican era. Gazi Teacher Training Institute, founded in 1926, and other faculties of education assumed the task of training mathematics teachers. Teachers specialized in mathematics in these institutions conveyed knowledge to new generations using modern teaching techniques. Mathematics education at universities developed rapidly, with the departments of mathematics at Istanbul University and Ankara University becoming pioneers in the field. Research activities were encouraged at universities, and national and international academic collaborations in mathematics were expanded. From the 1980s onwards, steps were taken to incorporate technology into education, and computer-assisted mathematics instruction came into focus. Computers were first used in Turkish universities, and software and computational techniques were integrated into mathematics curricula. In addition, mathematics education reached wider audiences through distance education programs and open education faculties. In the 21st century, with the process of digitalization, mathematics education in Turkey has been supported by e-learning platforms, interactive software, and remote learning opportunities. Digital content and applications developed by TÜBİTAK and the Ministry of National Education offer students diverse learning experiences. However, there are still unresolved issues in mathematics education in Turkey. Problems such as educational inequality, teacher quality, implementation of current curricula, and lack of technological infrastructure require reform. In the future, to improve the quality of mathematics education, innovative approaches should be adopted in both pedagogical and technological domains. 128   MODERN RESEARCH AND INVESTIGATIONS IN NATURAL . . . Table 5.2 Key Periods in the Development of Mathematics Education in the Republic of Turkey Period Main Developments Institutions/Contributions 1920s–1930s Adoption of a secular and unified education system through the 1924 Law on the Unification of Education Establishment of the Gazi Teacher Training Institute (1926); modern teacher training begins. 1930s–1950s Development of comprehensive mathematics curricula across all education levels Focus on arithmetic and geometry in primary school; algebra and calculus in secondary school. 1950s–1980s Growth of mathematics education and research at the university level. Istanbul and Ankara University mathematics departments played a pioneering role. 1980s–2000s Integration of computers and educational technology into math instruction Computer-assisted teaching introduced in universities; open and distance education expanded. 2000s– Present Widespread use of digital tools and e-learning in mathematics education. TÜBİTAK and the Ministry of Education developed interactive platforms and content Table 5.2 outlines the historical development of mathematics education in Turkey during the Republican era, dividing key transformations into five chronological periods. The table presents both pedagogical and institutional reforms, such as the unification of education under secular principles in the 1920s, the creation and evolution of curricula throughout the mid-century, and the integration of technology and digital resources in more recent decades. Key institutions, such as Gazi Teacher Training Institute, Istanbul University, and Ankara University, played foundational roles in shaping teacher education and research capacity. The references cited provide scholarly support for each period and reflect the continuity and shifts in Turkey’s mathematics education landscape over time. 6. Comparative Analysis and Evaluation Although mathematics education has developed differently across the world throughout various historical periods, there are certain fundamental commonalities. In ancient times, applied mathematics was emphasized, whereas in ancient Greece and the Islamic world, abstract and theoretical mathematics THE HISTORICAL DEVELOPMENT OF MATHEMATICS EDUCATION . . .   129 received significant attention. During the Middle Ages in Europe, mathematics education was dominated by a religious approach, while in the Renaissance and Enlightenment periods, secular and scientific education came to the forefront. In Turkey, the transition from traditional education to a modern and secular education system has been relatively rapid and systematic. In the era of technology and digitalization, as in the rest of the world, innovative methods have begun to be implemented in mathematics education in Turkey. Table 6.1 Periodical Development of Mathematics Education in the Republic of Turkey Period Educational and Institutional Features Early Years of the Republic (1923– 1950) Education was unified with the Law on Unification of Education, and curricula were developed. Arithmetic and geometry are emphasized in primary education; algebra, analysis, and trigonometry are emphasized in high school. Teacher Training And Universities (1950–1980) Development of mathematics teacher education at Gazi Institute of Education and universities. Academic research increased, and national and international collaborations began. Integration of Technology (1980–2000) Computer-assisted instruction started. Software and computational techniques were incorporated into curricula. Distance education and open education faculties became widespread. Digitalization and Present Day (2000–present) E-learning platforms, interactive software, and digital content projects (TÜBİTAK, Ministry of National Education) were developed. Educational inequalities and infrastructure problems continue. Table 6.1 summarizes the main developmental stages of mathematics education during the Republic of Turkey era, highlighting the prominent institutional, pedagogical, and technological changes in each period. The process, which began with efforts for unification and secularization in education, was strengthened by teacher training and university reforms and continued with the integration of technology and digitalization, yet educational inequalities and infrastructure issues still require solutions. 7. Conclusion and Recommendations This book chapter has comprehensively examined the historical evolution of mathematics education from ancient times, through the medieval Islamic 136   MODERN RESEARCH AND INVESTIGATIONS IN NATURAL . . . Kähler manifolds and their submanifolds. The subsequent section is devoted to the formal definition of pseudo-slant submanifolds within the framework of Kähler manifolds, along with a detailed investigation of their essential geometric properties. 2. PRELIMINERS Let  be a Riemannian manifold with an almost complex structure and a Hermitian metric satisfying , ( ) ( ) ( ) ( ) (2.1) for any ( ) where ( ) is the Lie algebra of vector fields in , then (  ) is called an almost Hermitian manifold. If an almost complex structure satisfies (  ) (2.2) for any ( ), where  is the Levi-Civita connection on , then  is called a Kaehler manifold (Chen,2009). Let be a submanifold of (  ). Where induced metric on Furthermore, let and be the induced connections on and of , respectively. The Gauss and Weingarten formulas for this setting are expressed as follows:  ( ) (2.3) and  (2.4) for all ( ), ( ) The second fundamental form and the shape operator are connected by the following relationship. ( ) ( ( )) ሺʹǤͷሻ for all ( ), ( ) The mean curvature vector of is given by ∑ ( )  ሺʹǤ͸ሻ AN INVESTIGATION ON PSEUDO-SLANT SUBMANIFOLDS OF KÄHLER . . .   137 here dim( ) * + is a local orthonormal frame of let be a submanifold of (  ) The submnifold is said to be totally umbilical if the second fundamental form satisfies ( ) ( )  ሺʹǤ͹ሻ for all vector fields tangent to here is the mean curvature vector. A submnifold is said to be totally geodesic if the second fundamental form and the manifold is said to be minimal if the mean curvature vector let be a submanifold of . Then for any ( ) we get  ሺʹǤͺሻ In this context, represents the tangent part, while denotes the normal part of . Similary for ( ) we get  ሺʹǤͻሻ In this context, represents the tangent part, while denotes the normal part of Let be a submanifold of Kähler (  ) Then for any ( ) we get here  and  On the other hand. let be a submanifold of Kähler (  ). Then for any ( ) we get so  138   MODERN RESEARCH AND INVESTIGATIONS IN NATURAL . . . and  . Proposition 2.1 let be a submanifold of Kähler manifold (  ) Then we have ( ) ( )  ሺʹǤͳͲሻ ( ) ( )  ሺʹǤͳͳሻ  ( ) ( ) ሺʹǤͳʹሻ for any ( ) and for any ( ) Proof: By applying equations (2.8) and (2.9) to (2.1), we have (2.10) and (2.11) to (2.12). Proposition 2.2 let be a submanifold of Kähler manifold (  ) Then we have ( ) ( )ǡ ( )  ሺʹǤͳ͵ሻ for any ( ). and ( ) ( )ǡ ( )  ሺʹǤͳͶሻ for any ( ) Proof: From (2.1) , by using (2.8) and (2.9), we obtain ( ) ( ) ( ) ( ) ( ) Thus, ( ) ( ), ( ) , for any ( ). ( ) ( ) ( ) ( ) ( ) AN INVESTIGATION ON PSEUDO-SLANT SUBMANIFOLDS OF KÄHLER . . .   139 Thus, ( ) ( ) , ( ) for any ( ) Therefore, ( ) and ( ) forms a Kähler structure on . where the covariant derivatives of the tensor fields and are defined as follows: ( )  ሺʹǤͳͷ ( )  ሺʹǤͳ͸ሻ ( )  ሺʹǤͳ͹ሻ and ( )  ሺʹǤͳͺሻ for any ( ) for any ( ) Proposition 2.3. let be a submanifold of Kähler manifold (  ) Then we have ( ) ( ) ሺʹǤͳͻሻ ( ) ( ) ( )  ሺʹǤʹͲሻ ( )  ሺʹǤʹͳሻ and ( ) ( )  ሺʹǤʹʹሻ For any ( ) for any ( ) 3. SLANT SUBMANIFOLDS OF KAHLER MANIFOLDS Some characterizations of slant submanifolds in a Kähler manifold have been provided. 140   MODERN RESEARCH AND INVESTIGATIONS IN NATURAL . . . Definition 3.1. A submanifold is called slant if the angle ( ) between and the tangent space is constant, independent of the choice of the point and the tangent vector . In this context, invariant and antiinvariant submanifolds appear as particular cases of slant submanifolds with slant angle ( ) and ( = ), respectively. A slant submanifold is referred to as a proper slant submanifold when it is neither invariant nor anti-invariant (Chen,1990;Lotta,1996). Theorem 3.2. Let be a submanifold of a Kähler manifold . Then is a slant submanifold if and only if ǡ , -ǡ ሺ͵Ǥͳሻ where denotes the tangential component of the almost complex structure , with being the slant angel of (Chen,1990;Lotta,1996). Lemma 3.3. Let ( ) be a slant submanifold ofa Kähler manifold (  ). Then, we have ( ) ( ) ሺ͵Ǥʹሻ ( ) ( ) ሺ͵Ǥ͵ሻ for all ( ) (Chen,1990;Lotta,1996). Proof. From (2.10) and (3.1), we can conclude that ( ) ( ) ( ) ( ) The equations in (2.1) and (2.8) result in ( ) ( ) ( ) ( ) ( ) ( ). 4. PSEUDO-SLANT SUBMANIFOLDS OF KAHLERMANIFOLDS Some characterizations of pseudoslant submanifolds in a Kähler manifold have been provided. AN INVESTIGATION ON PSEUDO-SLANT SUBMANIFOLDS OF KÄHLER . . .   141 Definition 4.1. Let be a submanifold of a Kähler manifold (  ) is pseudo-slant submanifold if there exist two orthogonal distributions and on such that  The tangent bundle has an orthogonal direct sum decomposition expressed as  is anti-invariant, which means that  is a slant, implying that the angle between and ( ) remains constant (Khan et al.,2007). Remark4.2. Let us asume that is a pseudo slant submanifold of a Kähler manifold (  ) Let p =dim( ) and q=dim( ) we can distinguish the following six cases:  If , is anti-invariant submanifold.  If and , then is invariant submanifold.  If and . /, then is classified as proper slant submanifold.  If , is anti-invariant submanifold  If and q≠0 with then is a semi-invariant.  If and q≠0 with . /, then is considered pseudo-slant submanifold. Let μ, represent the orthogonal complement of in In this case, can be expressed as the following decomposition: [15]. Definition 4.3. Let ( ) be a submanifold of a Kähler manifold (  ) Denote by the second fundamental form of . The submanifold is called -geodesic if ( ) for any ( ), and -geodesic if ( ) for any ( ) Furthermore, if the mixed component of the second fundamental form vanishes, that is, 142   MODERN RESEARCH AND INVESTIGATIONS IN NATURAL . . . ( ) , for any ( ) and ( ), then the submanifold is referred to as a mixed geodesic submanifold. Theorem 4.4. Let ( ) be a pseudo-slant submanifold of a Kähler manifold (  ) If the normal bundle is parallel, then, can be classified as either a mixed geodesic submanifold, an anti-invariant submanifold of  Proof. Asume that the normal bundle is parallel if and only if is parallel, If is parallel, then . For all ( ) ( ), ( ) We can conclude this from (2.5), (2.10), (2.11) and (2.21). ( ) ( ( ) ) ( ) ( ( ) ) ( ( ) ) ( ( ) ) ( ( ) ) Thus, we have ( ) ( ) for ( ), we have . Therefore, it follows that: ( ) By replacing with in the above equation, we obtain ( ) By replacing with in the above equation and using (3.1), we have ( ) ( ) Therefore, one of the following holds  , in which case is mixed geodesic submanifold,  ( ) correspondind to an anti invariant submanifold, Hence, the classification of follows from the parallelism of the normal bundle. AN INVESTIGATION ON PSEUDO-SLANT SUBMANIFOLDS OF KÄHLER . . .   143 Theorem 4.5. Let ( ) be a totally umbilical pseudo-slant submanifold of a Kähler manifold (  ) If the normal bundle is parallel, then, can be classified as either a minimal submanifold, an anti-invariant submanifold of  Proof. Let be a totally umbilical pseudo-slant submanifold of a Kähler manifold (  ) with parallel normal bundle . Parallel of implies that the tangential part of is parallel ( ), so the tangent distribution is invariant under . Let ( ) , ( ). We can conclude this from (2.5), (2.10), (2.11) and (2.21). Taking the inner product with , it follows that ( ( ) ) ( ( ) ) Since ( ) implies we obtain ( ) By replacing with in the above eq. we get ( ) Because is totally umbilical submanifold, from (2.7) we have ( ) where is the mean curvature vector. Then from (3.1) ( ) ( ) Hence, one of the following cases occurs:  , in which case is minimal submanifold.  ( ) correspondind to an anti invariant submanifold. Therefore, the classification of follows. Theorem 4.6. Let ( ) be a pseudo-slant submanifold of a Kähler manifold (  ) Asume that 144   MODERN RESEARCH AND INVESTIGATIONS IN NATURAL . . . ( ( ) ) for any ( ) and ( ) Than the distribution integrable, and the leaves of are geodesic in . Proof. Let ( ) be a pseudo-slant submanifold of a Kähler manifold (  ) For all ( ) and ( ) by the Gauss formula we have  ( ) Taking the inner product with ( ( ) ) (  ) Since  , we get ( ( ) ) (  ) (  ). ( ) and it follows that ( ( ) ) ( ( ) ) ( ) ( ) Thus the condition ( ( ) ) implies , - ( ), so the leaves of are geodesic in . Theorem 4.7. Let M be a pseudo-slant submanifold in a Kähler manifold (  ) If the normal component is parallel on the slant distribution , then either  is a geodesic submanifold, or  The second fundamental form ( ) is an eigenvector of with eigenvalues . Proof. Let M be a pseudo-slant submanifold of (  ) For any , we decompose , where is tangential and is normal. By the definition of pseudoslant submanifold, the tangential part satisfies AN INVESTIGATION ON PSEUDO-SLANT SUBMANIFOLDS OF KÄHLER . . .   145 Now assume that the normal component is parallel on . Then, for all we have  ሺͶǤͳሻ On the other hand, by (2.4)  . Using (4.1) , we get  Projecting onto the normal bundle yields ( ) if ( ), then we have for all ( ) Thus the leaves of the distribution are totally geodesic in , and thus, is -geodesic submanifold. If ( ) , then by the pseudo-slant condition and (3,1) we deduce that ( )= ( ), Thus, ( ) is an eigenvector of with the required eigenvalues. This completes the proof. Theorem 4.8. Let be a pseudo-slant submanifold in a Kähler manifold (  ) Then the anti-invariant distribution is integrable if and only if where denotes the shape operator. Proof. Since is a pseudo-slant submanifold, for all ( ) we have by using (2.15) (, -) if and only if = . On the other hahd from (2.3), (2.4), for all ( ) (( ) ) ( ) ( ( ) )  ሺͶǤʹሻ By the symmetry of , this implies Conversely, suppose , for all ( ) then ( ( ) ) ( ( ) ) ( ) , for any ( )