Malzeme Bilimi ve Nanoteknoloji Mühendisliği Bölümü Koleksiyonu

Permanent URI for this collectionhttps://hdl.handle.net/20.500.12573/207

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Horseradish peroxidase (HRP) nanoflowers-mediated polymerization of vinyl monomers
(SPRINGER NATURE LINK, 2024) Ozaydin, Gulbahar; Mirioglu, Muge; Kaplan, Naime; Dadi, Seyma; Ocsoy, Ismail; Gokturk, Ersen; 0000-0001-6280-3966; AGÜ, Mühendislik Fakültesi, Malzeme Bilimi ve Nanoteknoloji Mühendisliği Bölümü; Dadi, Seyma
The effects of flower-shaped hybrid nano biocatalyst (hFe-NFs) from coordination between horseradish peroxidase (HRP) enzyme and Fe2+ ions on the free-radical polymerization reactions of three different vinyl monomers (styrene, methylmethacrylate and acrylamide) were investigated. Polymerizations of styrene and methylmethacrylate (MMA) were performed under emulsion conditions using three different surfactants in the presence of acetylacetone (AcAc) and hydrogen peroxide (H2O2) initiator. Polymerization of water soluble acrylamide was accomplished under surfactant-free media. According to the obtained outcomes, hFe-NFs exhibited higher catalytic activity towards polymerization of vinyl monomers compared to the free-HRP enzyme in terms of yields and the number average molecular weights (Mn) of the synthesized polymers. hFe-NFs also demonstrated very high thermal stability. While optimum polymerization of styrene was achieved at room temperature (RT), the highest polymerization yields for acrylamide and MMA were respectively accomplished at 70 and 60 degrees C in which free-HRP enzyme loses its catalytic activity. Preparation of the flower-shaped hFe-NFs, therefore, enables inexpensive and stable catalyst system for free-radical polymerization of vinyl monomers compared to free-HRP enzyme. Increasing catalytic activity and stability of hFe-NFs at higher reaction temperatures are very crucial for utilization of these types of catalysts in both scientific and industrial purposes.
Electrochemical and Optical Multi-Detection of Escherichia coli Through Magneto-Optic Nanoparticles: A Pencil-on-Paper Biosensor
(MDPI, 2024) Soysaldi, Furkan; Ekici, Derya Dincyurek; Soylu, Mehmet cagri; Mutlugun, Evren; 0000-0003-1120-5557; 0000-0001-5807-9944; AGÜ, Mühendislik Fakültesi, Malzeme Bilimi ve Nanoteknoloji Mühendisliği Bölümü; Ekici, Derya Dincyurek; Mutlugun, Evren
Escherichia coli (E. coli) detection suffers from slow analysis time and high costs, along with the need for specificity. While state-of-the-art electrochemical biosensors are cost-efficient and easy to implement, their sensitivity and analysis time still require improvement. In this work, we present a paper-based electrochemical biosensor utilizing magnetic core-shell Fe2O3@CdSe/ZnS quantum dots (MQDs) to achieve fast detection, low cost, and high sensitivity. Using electrochemical impedance spectroscopy (EIS) as the detection technique, the biosensor achieved a limit of detection of 2.7 x 10(2) CFU/mL for E. coli bacteria across a concentration range of 10(2)-10(8) CFU/mL, with a relative standard deviation (RSD) of 3.5781%. From an optical perspective, as E. coli concentration increased steadily from 10(4) to 10(7) CFU/mL, quantum dot fluorescence showed over 60% lifetime quenching. This hybrid biosensor thus provides rapid, highly sensitive E. coli detection with a fast analysis time of 30 min. This study, which combines the detection advantages of electrochemical and optical biosensor systems in a graphite-based paper sensor for the first time, has the potential to meet the needs of point-of-care applications. It is thought that future studies that will aim to examine the performance of the production-optimized, portable, graphite-based sensor system on real food samples, environmental samples, and especially medical clinical samples will be promising.
Discovery of a C-S lyase inhibitor for the prevention of human body malodor formation: tannic acid inhibits the thioalcohol production in Staphylococcus hominis
(SPRINGER NATURE LINK, 2025) Fidan, Ozkan; Karipcin, Ayse Doga; Kose, Ayse Hamide; Anaz, Ayse; Demirsoy, Beyza Nur; Arslansoy, Nuriye; Sun, Lei; Mujwar, Somdutt; 0000-0001-5312-4742; 0009-0005-7132-842X; 0009-0008-5514-8711; 0000-0003-4037-5475; AGÜ, Yaşam ve Doğa Bilimleri Fakültesi, Biyomühendislik Bölümü; Fidan, Ozkan; Karipcin, Ayse Doga; Kose, Ayse Hamide; Anaz, Ayse; Demirsoy, Beyza Nur; Arslansoy, Nuriye
Human body odor is a result of the bacterial biotransformation of odorless precursor molecules secreted by the underarm sweat glands. In the human axilla, Staphylococcus hominis is the predominant bacterial species responsible for the biotransformation process of the odorless precursor molecule into the malodorous 3M3SH by two enzymes, a dipeptidase and a specific C-S lyase. The current solutions for malodor, such as deodorants and antiperspirants are known to block the apocrine glands or disrupt the skin microbiota. Additionally, these chemicals endanger both the environment and human health, and their long-term use can influence the function of sweat glands. Therefore, there is a need for the development of alternative, environmentally friendly, and natural solutions for the prevention of human body malodor. In this study, a library of secondary metabolites from various plants was screened to inhibit the C-S lyase, which metabolizes the odorless precursor sweat molecules, through molecular docking and molecular dynamics (MD) simulation. In silico studies revealed that tannic acid had the strongest affinity towards C-S lyase and was stably maintained in the binding pocket of the enzyme during 100-ns MD simulation. We found in the in vitro biotransformation assays that 1 mM tannic acid not only exhibited a significant reduction in malodor formation but also had quite low growth inhibition in S. hominis, indicating the minimum inhibitory effect of tannic acid on the skin microflora. This study paved the way for the development of a promising natural C-S lyase inhibitor to eliminate human body odor and can be used as a natural deodorizing molecule after further in vivo analysis.
N-Type Molecular Thermoelectrics Based on Solution-Doped Indenofluorene-Dimalononitrile: Simultaneous Enhancement of Doping Level and Molecular Order
(WILEY- Advanced, 2025) Wang, Suhao; Wei, Huan; Rillaerts, Antoine; Deneme, Ibrahim; Depriester, Michael; Manikandan, Suraj; Andreasen, Jens Wenzel; Daoudi, Abdelylah; Peralta, Sebastien; Longuemart, Stephane; Usta, Hakan; Cornil, Jerome; Hu, Yuanyuan; Pisula, Wojciech; 0000-0001-9415-0242; 0000-0002-0618-1979; AGÜ, Mühendislik Fakültesi, Malzeme Bilimi ve Nanoteknoloji Mühendisliği Bölümü; Usta, Hakan; Deneme, Ibrahim
The development of n-type organic thermoelectric materials, especially π-conjugated small molecules, lags far behind their p-type counterparts, due primarily to the scarcity of efficient electron-transporting molecules and the typically low electron affinities of n-type conjugated molecules that leads to inefficient n-doping. Herein, the n-doping of two functionalized (carbonyl vs dicyanovinylene) indenofluorene-based conjugated small molecules, 2,8-bis(5-(2-octyldodecyl)thien-2-yl)indeno[1,2-b]fluorene-6,12-dione (TIFDKT) and 2,2′-(2,8-bis(3-alkylthiophen-2-yl)indeno[1,2-b]fluorene-6,12-diylidene)dimalononitrile (TIFDMT) are demonstrated, with n-type dopant N-DMBI. While TIFDKT shows decent miscibility with N-DMBI, it can be hardly n-doped owing to its insufficiently low LUMO. On the other hand, TIFDMT, despite a poorer miscibility with N-DMBI, can be efficiently n-doped, reaching a respectable electrical conductivity of 0.16 S cm−1. Electron paramagnetic resonance measurements confirm the efficient n-doping of TIFDMT. Based on density functional theory (DFT) calculations, the LUMO frontier orbital energy of TIFDMT is much lower, and its wave function is more delocalized compared to TIFDKT. Additionally, the polarons are more delocalized in the n-doped TIFDMT. Remarkably, as indicated by the grazing-incidence wide-angle X-ray scattering (GIWAXS), the molecular order for TIFDMT thin-film is enhanced by n-doping, leading to more favorable packing with edge-on orientation and shorter π-π stacking distances (from 3.61 to 3.36 Å). This induces more efficient charge transport in the doped state. Upon optimization, a decent thermoelectric power factor of 0.25 µWm−1K−2 is achieved for n-doped TIFDMT. This work reveals the effect of carbonyl vs dicyanovinylene on the n-doping efficiency, microstructure evolution upon doping and thermoelectric performance, offering a stepping stone for the future design of efficient n-type thermoelectric molecules.
Structurally Colored Physically Unclonable Functions with Ultra-Rich and Stable Encoding Capacity
(WILEY-Advanced, 2025) Esidir, Abidin; Ren, Miaoning; Pekdemir, Sami; Kalay, Mustafa; Kayaci, Nilgun; Gunaltay, Nail; Usta, Hakan; Huang, Xian; Onses, Mustafa Serdar; 0000-0002-0618-1979; AGÜ, Mühendislik Fakültesi, Malzeme Bilimi ve Nanoteknoloji Mühendisliği Bölümü; Usta, Hakan
Identity security and counterfeiting assume a critical importance in the digitized world. An effective approach to addressing these issues is the use of physically unclonable functions (PUFs). The overarching challenge is a simultaneous combination of extremely high encoding capacity, stable operation, practical fabrication, and a widely available readout mechanism. Herein this challenge is addressed by designing an optical PUF via exploiting the thickness-dependent structural color formation in nanoscopic films of ZnO. The structural coloration ensures authentication using widely available bright-field-based optical readout, whereas the metal oxide provides a high degree of structural stability. True physical randomness in spatial position is achieved by physical vapor deposition of ZnO through stencil masks that are fabricated by pore formation in polycarbonate membranes via photothermal processing of stochastically positioned plasmonic nanoparticles. Structural coloration emerges from thin film interference as confirmed via simulation studies. The rich color variation and stochastic definition of domain size and geometry result in chaotic features with an encoding capacity that approaches (6.4 x 105)(2752x2208). Deep learning-based authentication is further demonstrated by transforming these chaotic features into unbreakable codes without field limitations. This ultra-rich encoding capacity, coupled with outstanding thermal and chemical stability, forms a new cutting edge for state-of-the-art PUF-based encoding systems.
Macronutrients in diets differentially affect gastrointestinal cytokine and tight junction protein levels
(UNIV PUTRA MALAYSIA PRESS, 2025) Ulutas, M. S.; Cebeci, A.; 0000-0002-2044-726X; 0000-0002-6158-8798; AGÜ, Mühendislik Fakültesi, Malzeme Bilimi ve Nanoteknoloji Mühendisliği Bölümü; Cebeci, A.
Western diet is known to result in intestinal inflammation and loss of barrier function. In the present work, we investigated whether other macronutrients contribute to inflammation and destabilising barrier function in mice, without using any inflammatory agents, to see the sole effects of dietary intervention. The present work was designed to determine the direct effects of diet on the intestinal barrier function and inflammation, using eight diets that differed on carbohydrate, fat, and fibre ratios for 17 weeks. At the end of the study, a distinct difference in mRNA expressions of cytokines and tight junction proteins was observed between intestinal and colon samples. Small intestinal cytokine expressions showed no difference among different diets, and tight junction protein expressions were only significant for occludin and ZO-1 in high carbohydrate diets. Colon samples had significantly different TNFα and IL-6 expressions among diets, especially in high carbohydrate diets. Tight junction protein expressions also differed significantly among diets, and low carbohydrate zero fibre diet had the lowest expression levels compared to the rest of diets. The present work reveals that not only western diet, but also diets high in carbohydrate negatively affect intestinal health, resulting in significant changes in inflammation markers. The role of carbohydrate and fiber contents are also observed in regulating tight junction protein expression. Based on these findings, adjusting macronutrient ratios can be used as a potential approach to help manage intestinal inflammation, though further research is needed.
A functional barley-based fermented soup (tarhana) with high β-glucan content
(SPRINGER, 2025) Koksel, Hamit; Ozkan, Kubra; Tekin-Cakmak, Zeynep Hazal; Karasu, Salih; Kahraman, Kevser; Oruc, Sena; Sagdic, Osman; Sestili, Francesco; 0000-0002-2786-3944; AGÜ, Mühendislik Fakültesi, Malzeme Bilimi ve Nanoteknoloji Mühendisliği Bölümü; Kahraman, Kevser
This study investigates the impact of using different flours, including high beta-glucan barley, on the nutritional properties of tarhana. Mineral composition, phenolic content, and antioxidant capacity of tarhana powder samples produced using flours of high beta-glucan hull-less barley (cv. Chifaa; ChF), hull-less barley cv. Yalin (YF), bread wheat cv. Tosunbey (white flour: TWF1 and whole wheat flour: TWF2). Furthermore, in vitro glycemic index (GI), pasting properties, and RVA soup index of their soups were investigated. Tarhana made with Chifaa barley flour (Tar-ChF) exhibited significantly higher levels of key minerals (K, Mg, Ca), beta-glucan and total phenolic content compared to those made with other flours (Tar YF, Tar TWF1, and Tar TWF2). Barley tarhana samples also showed greater antioxidant activity of bound phenolic fractions and lower GI values, indicating a healthier profile. The study highlights the potential of high beta-glucan barley flour to enhance tarhana's nutritional benefits without significantly affecting its sensory properties, such as color and viscosity. This research supports the integration of health-promoting ingredients like barley flour into traditional Mediterranean foods to improve their nutritional quality.
Production of high-grade antimony oxide from smelter slag via leaching and hydrolysis process
(ELSEVIER, 2025) Ibrahim, Ahmedaljaali Ibrahim Idrees; Aboelgamel, Muhammed; Soylu, Kartal Kaan; Top, Soner; Kursunoglu, Sait; Altiner, Mahmut; 0000-0003-3486-4184; AGÜ, Mühendislik Fakültesi, Malzeme Bilimi ve Nanoteknoloji Mühendisliği Bölümü; Top, Soner
This study aimed to investigate the recovery of antimony (Sb) from slag generated in an antimony smelting plant using leaching followed by hydrolysis processes. The leaching behaviors of rare earth elements (REEs) were also examined. The physicochemical properties of the slag were determined using various analytical techniques. The slag (4.12 % Sb) was mainly composed of quartz and minor minerals, including microline, magnetite, heden-bergite, and stibiconite. The Sb types in the slag determined by XPS were found to be in the oxide form. The concentrations of REEs (La, Y, Ce, and Nd) in the slag were 169.21 g/t. Preliminary leaching experiment results indicate that (i) HCl was selected rather than other acids due to its high extraction ability on the Sb from the slag, (ii) a sample with a d50 of <25 mu m should be used, (iii) the slurry should be mixed at 300 rpm. In the following leaching tests, the effects of leaching parameters (HCl acid concentration, amount of tartaric acid, solid-to-liquid ratio, reaction temperature, and time) on the extraction rates of Sb, impurities, and REEs were investigated. At the best leaching conditions (HCl: 8 M, amount of tartaric acid: 1 g/L, stirring speed: 300 rpm, reaction tem-perature: 75 C-degrees, and time: 180 min), the extraction rates of Sb from the slag were determined to be 91.19 %, but the extraction rates of REEs were measured to be <= 50 %. The activation energy (Ea) for Sb leaching was found to be 46.75 kJ/mol, indicating that the reaction was governed by the chemically controlled mechanism. In particular, it was understood from the additional experimental results that the leaching procedure should be carried out for 20 h to extract La with an extraction rate of >90 %. However, the extraction rate of Sb was negligible in extended times. It was determined that using tartaric acid positively affected La's leaching mech-anism, and the required leaching time for La decreased to 180 min from 20 h with the increase of tartaric acid from 1 g/L to 6 g/L. Hydrolysis tests were conducted using the Taguchi approach (L32, 2<^>1 4<^>3). The effects of the alkaline type (NH4OH and NaOH), stirring speed (100, 200, 300, and 400 rpm), temperature (50, 60, 70, and 80 C-degrees), and pH (1.5, 2, 2.5, and 3) on the precipitation of Sb from the PLS were investigated. NH4OH was suggested for use in the hydrolysis test to obtain precipitates with higher purities. The product obtained under the optimal conditions comprised 81.43 % Sb, 16.23 % O, and 2.34 % Fe. The product was identified as antimony oxide by XRD
A review on the recovery of high-grade critical metals from spent petroleum catalysts for meeting the demands of Industry 5.0
(TAYLOR & FRANCIS INC, 2024) Taz, Dilara; Ozsarac, Safak; Kursunoglu, Sait; Kursunoglu, Nilufer; Top, Soner; Altiner, Mahmut; 0000-0003-3486-4184; AGÜ, Mühendislik Fakültesi, Malzeme Bilimi ve Nanoteknoloji Mühendisliği Bölümü; Top, Soner
In solvent extraction studies, various extractants, including TOPO, Alamine 308, TBP, TOA, LIX 84I, LIX 63, and Aliquat 336, were employed for the extraction and separation of vanadium, molybdenum, and cobalt from aqueous solutions of spent petroleum catalysts. Results indicated efficient metal recovery using these extractants. Furthermore, a combination of techniques, such as roasting, chemical or bioleaching, solvent extraction (SX), and precipitation, exhibited promising results in achieving comprehensive metal extraction and separation. Important discoveries have been made in the study of recovering important metals from wasted petroleum catalysts, especially with regard to attaining high metal recovery efficiencies. It is found that the recovery efficiency for manganese is 85%, cobalt is 87%, and nickel is 93%. Furthermore, it shows that this procedure may be carried out with high efficiency, with vanadium recovery surpassing 90% and molybdenum recovery efficiency above 95%. These outcomes signify a significant advancement in the field of metal extraction and separation, aligning with the principles of Industry 5.0 while emphasizing sustainability and efficiency in the production of high-tech materials for the modern era.
A novel evaluation methodology for dimension stone quality
(Mining Science, 2024) Köken, Ekin; Strzalkowski, Pawel; 0000-0003-0178-329X; AGÜ, Mühendislik Fakültesi, Malzeme Bilimi ve Nanoteknoloji Mühendisliği Bölümü; Köken, Ekin
The physical and mechanical properties of natural stones are crucial factors in determining their quality, predicting their durability, and assessing their potential uses. In this study, a novel method is introduced to assess the quality of dimension stone using the Fuzzy logic inference system (FIS). The FIS analysis results are described as dimension stone field performance coefficient (DSFPC), which indicates the quality of dimension stones. The analysis results are also compared with different approaches, and it is concluded that the proposed FIS model can reliably be used to quantify the quality of dimension stones. The present study, in this manner, contributes to the natural stone industry by proposing a comprehensive predictive model used to quantify the dimension stone quality based on critical physicomechanical rock properties.
EVALUATION OF THE CAPACITY OF APRON FEEDERS USED IN CRUSHING–SCREENING PLANTS BY RESPONSE SURFACE METHODOLOGY AND ARTIFICIAL INTELLIGENCE METHODS
(Muğla Sıtkı Koçman Üniversitesi, 2024) Köken, Ekin; 0000-0003-0178-329X; AGÜ, Fen Bilimleri Enstitüsü, Malzeme Bilimi ve Makine Mühendisliği Ana Bilim Dalı; Köken, Ekin
In this study, the capacity (Q) of Apron feeders is investigated through response surface methodology (RSM) and some artificial intelligence methods. In this regard, a comprehensive field survey is performed to compile quantitative data on the common working conditions of Apron feeders used in the Turkish Mining Industry (TMI). Based on the collected data, RSM analyses are performed to reveal the factors affecting the Q of Apron feeders. Accordingly, hopper width (B), the height of the material layer conveyed (D), conveyor speed (V), and fill factor (φ) are determined to be the most critical factors for the Q. Several interaction and contour plots are presented to observe the variations in the Q values. Moreover, several predictive models are also introduced to estimate the Q of apron feeders based on artificial intelligence methods such as multivariate adaptive regression spline (MARS), adaptive neuro-fuzzy inference system (ANFIS), and artificial neural networks (ANN). The performance of the established predictive models is assessed based on scatter plots, and it is found that the predictive model based on RSM methodology provides relatively better results than the ones found on soft computing-based predictive models. The presented predictive models can be reliably used to estimate the Q of Apron feeders with high capacity. However, crushing–screening plant designers should be careful when using established predictive models for assessing low-capacity Apron feeders. Based on the findings obtained, the present study demonstrates the applicability of RSM methodology and several artificial intelligence methods for evaluating the Q of Apron feeders.
Role of pretty nanoflowers as novel versatile analytical tools for sensing in biomedical and bioanalytical applications
(Wiley-Online Library, 2024) Dadi,Seyma; Ocsoy,Ismail; 0000-0001-6280-3966; AGÜ, Mühendislik Fakültesi, Malzeme Bilimi ve Nanoteknoloji Mühendisliği Bölümü; Dadi, Seyma
In recent years, an encouraging breakthrough in the synthesis of immobilized enzymes in flower‐shaped called “organic‐inorganic hybrid nanoflowers (hNFs)” with greatly enhanced catalytic activity and stability were reported. Although, these hNFs were discovered by accident, the enzymes exhibited highly enhanced catalytic activities and stabilities in the hNFs compared with the free and conventionally immobilized enzymes. Herein, we rationally uti lized the catalytic activity of the hNFs for analytical applications. In this comprehensive review, we covered the design and use of the hNFs as novel versatile sensors for electrochemical, colorimetric/optical immunosensors‐based detection strategies in analytical perspective.
Development of Comprehensive Predictive Models for Evaluating Böhme Abrasion Value (BAV) of Dimension Stones Using Non-Destructive Testing Methods
(MDPI, 2025) Köken, Ekin; 0000-0003-0178-329X; AGÜ, Mühendislik Fakültesi, Malzeme Bilimi ve Nanoteknoloji Mühendisliği Bölümü; Köken, Ekin
Due to the global demand for dimension stones, fast and reliable evaluation tools are essential for assessing the quality of dimension stones. For this reason, this study aims to develop comprehensive tools for estimating the abrasion resistance of various dimension stones from Turkey. Non-destructive rock properties, including dry density (rho d), water absorption by weight (wa), and pulse wave velocity (Vp), were determined to build a comprehensive database for soft computing analyses. Three predictive models were established using multivariate adaptive regression spline (MARS), M5P, and artificial neural networks (ANN) methodologies. The performance of the models was assessed through scatter plots and statistical indicators, showing that the ANN-based model outperforms those based on M5P and MARS. The applicability of the models was further validated with independent data from the existing literature, confirming that all models are suitable for estimating varying B & ouml;hme abrasion values (BAVs). A MATLAB-based software tool, called B & ouml;hme abrasion calculator (v1.00), was also developed, allowing users to estimate BAV values by inputting adopted non-destructive rock properties. This tool is available upon request, supporting the dimension stone industry and fostering future research in this field.
Atomic structure and properties of amorphous boron carbon nitride (BC2N): An ab initio study
(ELSEVIER, 2025) Durandurdu, Murat; 0000-0001-5636-3183; AGÜ, Mühendislik Fakültesi, Malzeme Bilimi ve Nanoteknoloji Mühendisliği Bölümü; Durandurdu, Murat
This study investigates the atomic structure and properties of amorphous boron carbon nitride (a- BC2N) using ab initio molecular dynamics simulations. Structural analysis reveals a layer-like topology with varied bonding environments. Unlike the ordered alternating C-C and B-N layers found in the lowest-energy crystalline BC2N structure, a-BC2N features a solid-solution-like arrangement, with B, C, and N atoms randomly distributed within each layer. This randomness gives rise to small, distinct C-rich and BN-rich domains and irregular short zigzag chains of C-C and B-N bonds within each layer. Electronic structure analysis suggests that a-BC2N is likely a semiconductor. Mechanically, a-BC2N displays properties typical of layered materials but with an enhanced bulk modulus.
Highly Potent New Probiotic Strains from Traditional Turkish Fermented Foods
(SPRINGER NATURE LINK, 2025) Yigit, Mehmet Burak; Cebeci, Aysun; 0000-0002-6158-8798; 0000-0002-6777-6773; AGÜ, Yaşam ve Doğa Bilimleri Fakültesi, Moleküler Biyoloji ve Genetik Bölümü; Cebeci, Aysun; Yigit, Mehmet Burak
Traditional Turkish fermented foods like boza, pickles, and tarhana are recognized for their nutritional and health benefits, yet the probiotic potential of lactic acid bacteria (LAB) strains isolated from them remains underexplored. Sixty-six LAB strains were isolated from fermented foods using bacterial morphology, Gram staining, and catalase activity. The isolates were differentiated at strain level by RAPD-PCR (Random Amplification of Polymorphic DNA-Polymerase Chain Reaction) and twenty-five strains were selected for further evaluation of acid and bile salt tolerance. Among these, ten strains exhibited high tolerance and were subsequently assessed for adhesion to Caco-2 colorectal carcinoma cells, antimicrobial activity, exopolysaccharide (EPS) production, lysozyme resistance, and hemolytic activity. Using k-means clustering, three strains: Lactiplantibacillus plantarum ES-3, Pediococcus pentosaceus N-1, and Enterococcus faecium N-2 demonstrated superior probiotic characteristics, including significant acid (100% survival at pH3.0) and 0.3% bile salt tolerance (57%, 64%, 67%), strong adhesion to intestinal cells (65%, 88%, 91%), high lysozyme resistance (88%, 88%, 77%), and produced high amounts of EPS. These strains show promising potential as probiotics and warrant further investigation to confirm their functional properties and potential applications.
Pressure-driven structural evolution of amorphous InN
(ELSEVIER, 2025) Durandurdu, Murat; 0000-0001-5636-3183; AGÜ, Mühendislik Fakültesi, Malzeme Bilimi ve Nanoteknoloji Mühendisliği Bölümü; Durandurdu, Murat
Through constant-pressure ab initio simulations, we have uncovered high-pressure phase transformations in amorphous indium nitride for the first time. Our results reveal a distinct two-step progression under compression. Initially, a polyamorphic transition occurs, where the low-density amorphous (LDA) phase transforms into a high-density amorphous (HDA) phase. This HDA structure remains stable in some pressure range and then crystallization initiates, leading to a rocksalt configuration. Upon decompression, the HDA phase reverts to an amorphous network with a slightly higher density and coordination number than the initial LDA state.
Phase-separated amorphous Si2BN: A computational study
(AIP Publishing, 2025) Durandurdu, Murat; 0000-0001-5636-3183; AGÜ, Mühendislik Fakültesi, Malzeme Bilimi ve Nanoteknoloji Mühendisliği Bölümü; Durandurdu, Murat
This study investigates the atomic structure, bonding, and electrical and mechanical properties of amorphous silicon boron nitride (a-Si2BN) using ab initio molecular dynamics simulations. The simulations reveal a distinct phase-separated structure comprising Si-rich and BN-rich domains. BN layers are embedded within the amorphous Si matrix, with only a few bridging atoms linking these regions. The Si-rich region exhibits topological similarities to amorphous silicon, albeit with notable structural distortions. Electronic structure calculations indicate semiconducting behavior with a small bandgap, while mechanical property analysis shows a moderate bulk modulus and Young's modulus, achieving a balance between rigidity and elasticity. These findings position a-Si2BN as a promising material for advanced applications, including flexible electronics, high-temperature semiconductors, and energy storage devices. While the proposed structure is currently hypothetical, its potential experimental realization could open new avenues in material design for emerging technologies.
Leaching of a complex Pb-Zn ore in sulfuric acid solution
(Niğde Ömer Halisdemir Üniversitesi, 2024) Ozsarac, Safak; Kursunoglu,Sait; Top, Soner; Altiner, Mahmut; Hussaini,Shokrullah; Gokcen, Hasan Serkan; Kaya,Muammer; 0000-0003-3486-4184; AGÜ, Mühendislik Fakültesi, Malzeme Bilimi ve Nanoteknoloji Mühendisliği Bölümü; Top, Soner
In this study, the leaching behavior of a Gazipasa-Aydap complex Zn-Pb ore sample in sulfuric acid solutions was investigated. Firstly, the chemical and mineralogical compositions of the ore sample were determined by AAS, ICP-OES, XRF, and XRD analyses. The ore seemed to be very complex, containing major amounts of zinc (16.4%), lead (10.6%), iron (2.6%), and a minor amount of copper (0.2%). The leaching experiments demonstrated that 86.7% Zn, 90% Cu, and 25.2% Fe could be taken into the leach solution under the following conditions: 2 M sulfuric acid concentration, 25 °C leaching temperature, 1/10 solid-toliquid ratio, and 125 rpm shaking rate. The effects of the leaching temperature on the metal dissolutions were also tested. The experimental results revealed that increasing the leaching temperature had no beneficial effect on zinc dissolution, but increased iron dissolution significantly. Overall, it was determined that zinc could be extracted from the complex ore using a short leaching time (30 min), a low leaching temperature (25 °C), a relatively low sulfuric acid concentration (2 M), and a relatively high solid-to-liquid ratio (2/10).
Inkjet Printing of Aqueous Silver Inks on Water-Soluble Fabrics for Transient Electronics Applications
(AMER CHEMICAL SOC, 2024) Gozutok-Onses, Zehra; Kiremitler, N. Burak; Ozbasaran, Aleyna; Huang, Xian; Onses, Mustafa Serdar; Usta, Hakan; 0000-0002-0618-1979; AGÜ, Mühendislik Fakültesi, Malzeme Bilimi ve Nanoteknoloji Mühendisliği Bölümü; Gozutok-Onses, Zehra; Usta, Hakan
There is an urgent need to develop practical routes for manufacturing transient electronic devices to tackle the emerging issue of electronic waste and enable next-generation devices. This study reports additive patterning of conductive layers on industrially available water-soluble nonwoven fabrics composed of poly(vinyl alcohol) (PVA). Aqueous inks composed of reactive silver precursors can be practically patterned over water-soluble fabrics by inkjet printing. The efficient deposition of materials with droplet volumes on the order of picoliters ensures the generation of conductive patterns on a water-soluble fabric using a solution-processable fabrication with aqueous inks. The fabrication of conductive electrodes and transience behavior are studied on PVA fabrics with two different degrees of hydrolysis, providing tunability in the temperature-dependent degradation of the substrate. The application of the printed conductive pads is demonstrated in resistive heaters. The temperature of the fabric can exceed 100 degrees C in less than 15 s at a safe voltage of 3 V. The heater exhibits stable operation under cyclic heating and cooling. The presented approach presents key opportunities in additive patterning of aqueous solutions and colloidal dispersions over water-soluble substrates for transient device applications.
DEVELOPMENT OF SOFT COMPUTING-BASED PREDICTIVE TOOLS FOR ESTIMATING THE YOUNG MODULUS OF WEAK ROCKS
(UNIV ZIELONA GORA, 2024) Koken, Ekin; Strzalkowski, Pawel; 0000-0003-0178-329X; AGÜ, Mühendislik Fakültesi, Malzeme Bilimi ve Nanoteknoloji Mühendisliği Bölümü; Koken, Ekin
The deformation characteristics of rocks are of vital importance in addressing most geomechanical issues as they are one of the most critical input parameters in rock engineering analyses. For this reason, robust forecasting models are required when analysing the stability of tunnels, slopes, mine galleries, and other underground excavations. In this research, novel predictive models are proposed to estimate the tangential Young modulus (Eti) of weak rocks. To achieve this, an extensive literature review is performed to obtain a comprehensive database including critical physico-mechanical properties of various weak rocks. Thanks to the advantages of soft computing methods such as genetic algorithm (GA), adaptive neuro-fuzzy inference system (ANFIS), artificial neural networks (ANN) and multivariate adaptive regression splines (MARS), novel predictive models are established. The effectiveness of the developed predictive models is investigated using various statistical measures and it is concluded that empirical models utilizing ANN and ANFIS methodologies are the most effective tools for estimating the Eti of weak rocks. In addition, a practical design chart is also developed for assessing the Eti of weak rocks.

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