Biyomedikal Mühendisliği Bölümü Koleksiyonu

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https://hdl.handle.net/20.500.14034/35

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Kafes yapılı konsol kirişin yapısal kullanımına yönelik ilk adımlar: System identification, modal ve yapısal analiz
(Bayburt Üniversitesi, 2024) Dokuz, Muhammed Enes; Gök, Kadir; Çaşka, Serkan
Kafes yapılı malzemeler birçok mühendislik alanında kullanılmaktadır. Ancak kafes yapılı kirişlerin dinamik ve statik analizini içeren çalışmalar literatürde yaygın değildir. Bu çalışmada kafes yapısına sahip üç tip konsol kiriş nTopology programında 3 boyutlu olarak tasarlanıp Ansys yazılımında analizleri yapılmıştır. Kirişlerin tasarımında kare döndürülmüş, altıgen ve üçgen tipi kafes yapıları kullanılmıştır. Her bir kirişe 10 Kilonewton kuvvet uygulanarak kirişlerin serbest uç kısmında meydana gelen yer değiştirmeler kaydedilmiştir. Kirişlerin titreşimine ait giriş ve çıkış veri seti kullanılarak ayrık zaman transfer fonksiyonu modelleri, ayrık zaman durum uzayı modelleri ve doğrusal olmayan Ekstra Girişli Otoregresif modeller elde edildi. Modellerin elde edilmesi için MATLAB'ın Sistem Tanımlama Araç Kutusu kullanıldı. Ayrıca kirişlerin modal analizi ve statik analizi gerçekleştirilmiştir. Sistem tanımlama, modal analiz ve statik analize ait sonuçlar şekiller halinde gösterilmiş, tablolar halinde sunulmuş ve tartışılmıştır. Kafes olmayan kirişten sonra en düşük spesifik deformasyon üçgen kafes kirişte meydana geldi. Bu nedenle üçgen kafes yapısı, saf eğilme durumundaki yapı elemanları için umut verici sonuçlar verdi.
Bir bisiklet gövdesinin sonlu elemanlar yöntemiyle statik analizi
(Bilecik Şeyh Edebali Üniversitesi, 2019) Erdem, Mehmet; Gök, Kadir; Tümsek, Mert; Gök, Arif
Bisiklet gövdesi, tüm parçaları bir araya getiren birleştirici güçtür. Bir bisiklet gövdesinin sahip olması gereken en önemli özellik düşük ağırlığa ve yüksek dayanıma sahip olmasıdır. Ancak gövde dayanımını birçok unsur belirler. Bu çalışmada bisiklet gövdesinin statik yük analizleri yapılarak, parçaya uygulanacak kuvvetlere karşı güvenilirliği hesaplanmıştır. Araştırmada bisiklet gövdesinin 3 boyutlu geometrik modeli, diğer bisiklet gövdelerinden özgün olarak bilgisayar destekli tasarım programı olan SolidWorks yardımıyla gerçekleştirilmiştir. Çalışmada, bisiklet gövdesinin uygulanan kuvvetler altındaki statik tepkilerini ölçmek için Sonlu Elemanlar Yöntemi kullanılmıştır. Sonuç olarak tasarımı yapılan bisiklet gövdesinin uygulanan kuvvetler altında güvenli olduğu ortaya çıkmış ve sonuçların doğruluğu ispatlanmıştır.
Spectroscopic evaluation of DNA binding activities of copper (II) phthalocyanine complex consisting of tetrakis-(4-Tritylphenoxy) ligand
(Gazi Üniversitesi, 2025) Arslantaş, Ali; Ağırtaş, Mehmet Salih; Solğun, Derya Güngördü
The structure and basic properties of Cu(II) phthalocyanine compound possessing tetrakis-(4-tritylphenoxy) group were elucidated in a past study with the help of absorption and infrared spectroscopic equipments. The electronic spectra, emission spectroscopy, gel agarose electrophoresis and thermal melting were employed to reveal the DNA interaction functions of this complex at changing concentrations of CT-DNA. In this experiment, the binding constant for the Cu(II) phthalocyanine compound which contains the tetrakis(4-tritylphenoxy) group was computed to be 1.53 x 106 M-1. The data obtained from absorption and fluorescence spectroscopic studies revealed that the CuPc compound reacted with CT-DNA through an intercalating mechanism. Well as the above methods, melting temperature and electrophoresis were also employed to analyse the interaction feature of CuPc with DNA. The interaction of the CuPc compound with DNA was also confirmed by data from melting temperature and electrophoresis experiments. Within the framework of the results obtained, it is predicted that CuPc compound may be a possible cancer therapeutic agent.
A digital twin-based study of material behavior in the rolling process
(Kırklareli Üniversitesi, 2024) Gök, Kadir; Esen, Cemal
The study proposes the development of a digital twin model for the rolling process. This virtual representation allows for the investigation of how various rolling parameters influence the quality of the final product. By employing finite element analysis (FEA), the model can simulate the rolling process under different conditions. Specifically, the study focuses only workpiece material which includes aluminum alloy (Al2024) for digital twin scenario. Through simulations, critical parameters like the Z-force exerted on the workpiece can be determined and compared. This enables researchers to evaluate different scenarios and identify optimal rolling conditions without the need for costly physical experiments.
Characterization of PbMo0.3W0.7O4 crystal: a potential material for photocatalysis and optoelectronic applications
(Wiley-V C H Verlag Gmbh, 2024) Işık, Mehmet; Gasanly, Nizami Mamed
PbMo0.3W0.7O4 semiconductor crystal, which contains the balanced ratios of Mo and W, is grown for the first time by Czochralski method. The structural and optical properties of the crystal are investigated in detail in the present study. Structural analysis shows that crystal has tetragonal structure like PbMoO4 and PbWO4 compounds. The optical characteristics are studied by transmission, Raman, FTIR and photoluminescence methods. The bandgap energy is found to be 3.18 eV, and the positions of the conduction and valence bands are determined. The vibrational characteristics are studied by means of Raman and FTIR spectroscopy techniques. Photoluminescence spectrum presents three peaks around 486, 529, and 544 nm which fall into the green emission spectral range. Taking into account the properties of the compound, it is stated that PbMo0.3W0.7O4 (or Pb(MoO4)(0.3)(WO4)(0.7)) has the potential to be used in water splitting applications and optoelectronic devices that emit green light.
Advanced antibacterial strategies for combatting biomaterial-associated infections: A comprehensive review
(Wiley, 2024) Kasapgil, Esra; Garay-Sarmiento, Manuela; Rodriguez-Emmenegger, Cesar
Biomaterial-associated infections (BAIs) pose significant challenges in modern medical technologies, being a major postoperative complication and leading cause of implant failure. These infections significantly risk patient health, resulting in prolonged hospitalization, increased morbidity and mortality rates, and elevated treatment expenses. This comprehensive review examines the mechanisms driving bacterial adhesion and biofilm formation on biomaterial surfaces, offering an in-depth analysis of current antimicrobial strategies for preventing BAIs. We explore antimicrobial-eluting biomaterials, contact-killing surfaces, and antifouling coatings, emphasizing the application of antifouling polymer brushes on medical devices. Recent advancements in multifunctional antimicrobial biomaterials, which integrate multiple mechanisms for superior protection against BAIs, are also discussed. By evaluating the advantages and limitations of these strategies, this review aims to guide the design and development of highly efficient and biocompatible antimicrobial biomaterials. We highlight potential design routes that facilitate the transition from laboratory research to clinical applications. Additionally, we provide insights into the potential of synthetic biology as a novel approach to combat antimicrobial resistance. This review aspires to inspire future research and innovation, ultimately improving patient outcomes and advancing medical device technology.
Characterization of Bi12SiO20 single crystal: understanding structural and thermal properties
(Springer Heidelberg, 2024) Altuntas, G.; Işık, Mehmet; Gasanly, N. M.
This study presents a thorough examination of the structural and thermal characteristics of Bi12SiO20 crystal. X-ray diffraction (XRD) analysis was employed to investigate the crystallographic structure, while scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS) were utilized to ascertain morphological features and elemental composition, respectively. The XRD spectrum exhibited numerous peaks corresponding to the cubic crystalline structure. Thermal behavior was investigated through thermal gravimetric analysis (TGA), differential thermal analysis (DTA) and differential scanning calorimetry (DSC). Within the crystal, negligible weight loss was observed up to 750 degrees C, followed by weight loss processes occurring in the temperature ranges of 750-919 degrees C and above 919 degrees C. The 2% weight loss in the range of 750-919 degrees C was associated with the decomposition process, and the activation energy of this process was found to be 199 kJ/mol considering Coats-Redfern expression. A significant weight loss was observed in the region above 919 C-o and was associated with the decomposition of the Bi12SiO20 compound and/or the melting processes of the components of the Bi12SiO20 compound. Three endothermic peaks were observed in the DTA plot. Additionally, DSC measurements conducted under varied heating rates indicated endothermic crystallization process around 348 degrees C, with an activation energy of 522 kJ/mol determined through the Kissenger equation. These findings present valuable details regarding the crystal's structural configuration, morphological attributes, and decomposition/phase transitions, thereby illuminating its potential applications across various fields.
Optimizing near infrared laser irradiation and photosensitizer accumulation period for indocyanine green-mediated photodynamic therapy in breast cancer xenografts: a focus on treatment and characterization
(Springer London Ltd, 2024) Tabakoğlu, Haşim Özgür; Aydogan, Tugba Kiris; Kiris, Aysenur; Akbulut, Saadet
Photodynamic therapy (PDT) is a promising cancer treatment approach. Indocyanine green (ICG) is a water-soluble tricarbocyanine dye with a peak absorption wavelength of around 800 nm and possesses the capacity to produce reactive oxygen species. FTIR spectroscopy is rarely used and offers insights into molecular changes in cancer studies. MCF-7 cells were injected into Nude mouse. Once the tumor had grown to a size of 3-4 mm, mice were randomized into the 12 PDT groups. After each mouse received 5 mg/kg of ICG, they were photo-irradiated with a diode laser emitting light at 809 nm, followed by waiting intervals of 0, 30, 60, and 90 min. Laser irradiation parameters were 150, 250, 500 mW/cm2 and irradiation duration was 1200s. The tumor size was measured every day for four days. The FTIR spectroscopy was used to perform spectral analysis on tumor tissue samples. Four distinct regions (3600-2800 cm-1, 1750-1550 cm-1, 1540-1450 cm-1, and 1700-1100 cm-1) were analyzed, and Hierarchical Cluster study was carried out. A decrease in tumor volume was observed with all PDT applications, except, increases in tumor volume was observed at 150mW 90-minute group. PDT administered after 90 min revealed variations in 150mW and 250mW laser powers in the 3600 cm-1-2800 cm-1 range. The 250mW and 500mW applications resulted in a considerable reduction in fibroadenoma and carcinoma tissues, according to an analysis comparing the A1695 / A1635 ratio. It is proposed that the ideal treatments for further investigation have a power output of 250 mW.
Spectroscopic ellipsometry study of linear and nonlinear optical properties of NaBi(Mo0.5W0.5O4)2 crystal
(Springer, 2024) Işık, Mehmet; Guler, I.; Gasanly, N. M.; Darvishov, N. H.
In this study, linear and nonlinear optical characteristics of NaBi(Mo0.5W0.5O4)(2) crystal, a new material that may have potential for optoelectronic applications, were investigated. NaBi(Mo0.5W0.5O4)(2) single crystals were grown via the Czochralski method. Two sharp and well-defined peaks were observed in the x-ray diffraction pattern. These peaks were associated with tetragonal crystal structure. The data obtained from ellipsometer measurements was matched with a suitable optical model. This allowed for the presentation of the spectral dependence of various optical parameters like refractive index, dielectric constant, optical conductivity, extinction, and absorption coefficients in the range of 1.2-5.0 eV. As a result of studying the spectral dependence of the absorption coefficient under Tauc relationship, bandgap energy of the compound was found to be 3.20 eV. Using the spectral dependence of the dielectric function, the existence of two critical points with energy values of 3.72 and 4.44 eV was revealed. The change of the refractive index in the region under the bandgap was studied using the single oscillator model. Single oscillator and dispersion energies were determined from the analysis results. Nonlinear optical parameters of NaBi(Mo0.5W0.5O4)(2) crystal were also determined. With this study, the optical properties of the NaBi(Mo0.5W0.5O4)(2) are presented in more detail and valuable information is presented for the potential use of the material in optoelectronic devices.
Development of a novel laboratory photodynamic therapy device: automated multi-mode LED system for optimum well-plate irradiation
(Springer London Ltd, 2024) Yildiz, Mustafa Zahid; Kamanli, Ali Furkan; Eskiler, Gamze Gueney; Tabakoğlu, Haşim Özgür; Pala, Muhammed Ali; Ozdemir, Ayla Eren
Multi-mode Automated Well-plate PDT LED Laboratory Irradiation System described.Automates and standardizes time-consuming experiments.LED wavelength and temperature stabilized for highly reproducible irradiations.Efficacy demonstrated in 5-aminolevulinic acid (5-ALA) treatments of HT-29 colon cancer cells and WI-38 human lung fibroblasts. Photodynamic therapy (PDT) is a targeted treatment method that utilizes a photosensitizer (PS) to induce cytotoxicity in malignant and non-malignant tumors. Optimization of PDT requires investigation of the selectivity of PS for the target tissues, irradiating light source, irradiation wavelengths, fluence rate, fluence, illumination mode, and overall treatment plan. In this study, we developed the Multi-mode Automatized Well-plate PDT LED Laboratory Irradiation System (MAWPLIS), an innovative device that automates time-consuming well plate light dosage/PS dose measurement experiment. The careful control of LED current and temperature stabilization in the LED module allowed the system to achieve high optical output stability. The MAWPLIS was designed by integrating a 3-axis moving system and motion controller, a quick-switching LED controller unit equipped with interchangeable LED modules capable of employing multiple wavelengths, and a TEC system. The proposed system achieved high optical output stability (1 mW) within the range of 0-500 mW, high wavelength stability (5 nm) at 635 nm, and high temperature stability (0.2 degrees C) across all radiation modes. The system's validation involved in vitro analysis using 5-ALA across varying concentrations, incubation periods, light exposures, and wavelengths in HT-29 colon cancer and WI-38 human lung fibroblast cell lines. Specifically, a combination of 405 nm and 635 nm wavelengths was selected to demonstrate enhanced strategies for colon cancer cell eradication and system validation. The MAWPLIS system represents a significant advancement in photodynamic therapy (PDT) research, offering automation and standardization of time-intensive experiments, high stability and precision, and improved PDT efficacy through dual-wavelength integration.
Exploring temperature-dependent bandgap and urbach energies in CdTe thin films for optoelectronic applications
(Elsevier, 2024) Surucu, O.; Surucu, G.; Gasanly, N. M.; Parlak, M.; Işık, Mehmet
This study examines CdTe thin films deposited via RF magnetron sputtering, focusing on structural and optical properties. X-ray diffraction, Raman spectroscopy, and SEM assessed structural characteristics. Optical properties were analyzed through transmittance measurements from 10 to 300 K. Tauc plots and Varshni modeling revealed a temperature-dependent bandgap, increasing from 1.49 eV at room temperature to 1.57 eV at 10 K. Urbach energy rose from 82.7 to 93.7 meV with temperature. These results are essential for applications where temperature affects CdTe-based device performance.
Development of VEGF mimetic QK peptide on polycaprolactone nanofiber for vascular tissue engineering
(Elsevier, 2024) Cevik, Ziysan Buse Yarali; Sunal, Gülşah; Taşkara, Aytan; Karaman, Ozan
Electrospinning allows promoting vascular tissue formation. Polycaprolactone (PCL) is a promising polymer for vascular tissue engineering because of its great mechanical strength and efficient fabrication. However, PCL shows limited biocompatibility owing to its hydrophobic structure. PCL nanofibers can be modified by peptides to improve biological activity. KLTWQELYQLKYKGI (QK) is a peptide that mimics the Vascular Endothelial Growth Factor (VEGF) by organizing endothelial cells. It is critically important to identify the optimum concentration of QK peptide conjugation onto PCL nanofiber for vascularization. Thus, PCL nanofibers were conjugated by different QK peptide concentrations (10 mu M, 100 mu M and 1000 mu M). QK conjugated nanofibers were characterized by Scanning Electron Microscopy (SEM) and Atomic Force Microscopy (AFM) analysis. The vascularization was evaluated by Live and Dead staining assay, real time PCR of platelet/endothelial cell adhesion molecule (PECAM-1), VEGF and vascular endothelial-cadherin (VE-cadherin) genes and VEGF immunofluorescence analysis. The surfaces of PCL nanofibers were modified by different concentrations of QK peptide. The roughness of nanofibers increased depending on the increased concentration of QK peptide. The higher cell attachment and cell viability were observed in 1000 mu M of QK peptide. 1000 mu M of QK peptide showed higher vasculogenic potential in terms of PECAM, VEGF, and VE-cadherin gene expression than all the other experimental groups. In the same on gene expression analysis by qPCR, 1000 mu M concentration of QK peptide showed the higher VEGF protein than the other experimental groups. 1000 mu M concentration of QK peptide can be used to improve the vasculogenic property of PCL nanofibers.
NaBi(MoO4)2 crystal: Defect states and luminescence properties for optoelectronic applications
(Elsevier, 2025) Işık, Mehmet; Altuntas, G.; Gasanly, N. M.; Darvishov, N. H.
This paper investigates the electronic and optical properties of NaBi(MoO4)2 crystal through absorbance, thermally stimulated current (TSC), and photoluminescence (PL) measurements. Absorbance analysis revealed important information about the bandgap and the degree of disorder within the material. The bandgap energy of the compound was found to be 2.94 eV. TSC measurements revealed the presence of hole defect centers and provided information regarding charge transport mechanisms. Two TSC peaks were observed at temperatures of 69.3 and 127.5 K, and the activation energies of the trap centers associated with these peaks were found to be 0.05 and 0.14 eV. Two PL peaks were observed around 487 and 536 nm corresponding to the blue and green emissions, respectively. These findings provide a comprehensive understanding the band structure of the NaBi (MoO4)2, highlighting its suitability for use in optoelectronic devices, sensors, and light-emitting applications.
Identification of shallow trap centers in InSe single crystals and investigation of their distribution: A thermally stimulated current spectroscopy
(Elsevier, 2024) Işık, Mehmet; Gasanly, N. M.
Identification of trap centers in semiconductors takes great importance for improving the performance of electronic and optoelectronic devices. In the present study, we employed the thermally stimulated current (TSC) method within a temperature range of 10-280 K to explore trap centers in InSe crystal-a material with promising applications in next-generation devices. Our findings revealed the existence of two distinct hole trap centers within the InSe crystal lattice located at 0.06 and 0.14 eV. Through the leveraging the T-stop method, we offered trap distribution parameters of revealed centers. The results obtained from the experimental methodology employed to investigate the distribution of trap centers indicated that one of the peaks extended between 0.06 and 0.13 eV, while the other spanned from 0.14 to 0.31 eV. Notably, our research uncovers a remarkable variation in trap density, spanning one order of magnitude, for every 10 and 88 meV of energy variation. The results of our research present the characteristics of shallow trap centers in InSe, providing important information for the design and optimization of InSe-based optoelectronic devices.
Unveiling the application potential of PbMo0.75W0.25O4 crystal: Linear and nonlinear optical properties through ellipsometry
(Elsevier, 2024) Işık, Mehmet; Gasanly, N. M.
PbMo0.75W0.25O4 compound is formed by replacing one quarter of the Mo atoms in the PbMoO4 with W atoms and has significant potential for optoelectronic applications. Optical properties of PbMo0.75W0.25O4 single crystal have been systematically investigated using ellipsometry measurements in the spectral range of 2.4-5.4 eV. The linear optical parameters, including refractive index, extinction coefficient, and absorption coefficient, were extracted from the obtained ellipsometry data. By analyzing spectral dependence of these parameters, band gap energy, critical point energy, and single effective oscillator parameters were determined. The refractive index spectrum was analyzed in the below band gap energy region by considering Cauchy and Sellmeier models. Additionally, nonlinear optical values were calculated, providing a comprehensive understanding of the optical properties of the PbMo0.75W0.25O4 single crystal. This study not only contributes to the fundamental understanding of the crystal's optical properties but also has potential implications for applications in optoelectronic devices and photovoltaics.
Revealing the effects of defect states on the nonlinear absorption properties of the tlInsse and Tl2In2S3Se crystals in near-infrared optical limiting applications
(Amer Chemical Soc, 2024) Dogan, Anil; Karatay, Ahmet; Işık, Mehmet; Yildiz, Elif Akhuseyin; Gasanly, Nizami Mamed; Elmali, Ayhan
The present study represents the effect of defect states on the nonlinear absorption and optical limiting performances of TlInSSe and Tl2In2S3Se single crystals with near-infrared excitations. The band gap energies were 2.2 and 2.22 eV, and the Urbach energies were 0.049 and 0.034 eV for TlInSSe and Tl2In2S3Se, respectively. The trapping time of localized defect states was found to be 8 ns by femtosecond transient absorption measurements. The analysis of open-aperture Z-scan data depends on two different fitting models to determine the effect of defect states on the nonlinear absorption (NA) properties of the studied crystals. Model 1 only considers two-photon absorption (TPA), while model 2 includes one-photon absorption (OPA), TPA, and free carrier absorption (FCA). The NA coefficients (ss(eff)) obtained from model 2 are higher than the values (ss) obtained from model 1 at the same intensities, revealing that defect states contribute to NA through OPA. The optical limiting properties of the TlInSSe and Tl2In2S3Se crystals were examined under 1064 nm wavelength excitation. The limiting thresholds were found to be 1.16 and 0.27 mJ/cm(2) at 29.8 GW/m(2) and 99.5 GW/m(2) input intensities, respectively. The results show that TlInSSe and Tl2In2S3Se crystals have promising potential for near-infrared optical limiting applications.
Nanoindentation study of PbMoO4 single crystals: mechanical properties and implications for applications
(Iop Publishing Ltd, 2025) Işık, Mehmet; Gasanly, N. M.
Nanomechanical properties of lead molybdate ( PbMoO 4 ) single crystal were investigated using nanoindentation measurements. The force-dependent Young's modulus and hardness of PbMoO4 along the [ 100 ] direction was determined using the Oliver-Pharr method. As the applied force increased, hardness and young modulus values decreased. This behavior was referred to the indentation size effect ( ISE ) . The force-dependent plots were analyzed using proportional specimen resistance model and true hardness value was determined as 1.84 GPa. As a result of increasing the applied force from 5 to 100 mN, the Young modulus decreased from 81.7 to 60.2 GPa. The dependencies of plastic and elastic deformation components were also reported in the present study. It was seen that plastic deformation is the dominant component. The fi ndings suggest that PbMoO4 is relatively soft material and can be considered as a promising material for mechanical and optoelectronics applications that require revealed hardness and Young's modulus values.
Investigation of the effect of elbow pipes of TI6AL4V, 304 stainless steel, AZ91 materials on erosion corrosion by finite element analysis
(Czech Technical Univ Prague, 2024) Gök, Kadir; Danismaz, Merdin; Urtekin, Levent; Ada, Hediye Deniz; Gok, Arif
Corrosion is the degradation of metals caused by chemical or electrochemical reactions with their environment. As a result of these reactions, undesirable conditions occur in the physical, chemical, mechanical and electrical properties of metals. These conditions cause parts made of metallic materials to become unusable. Erosion corrosion is one of the most common types of corrosion in fluid transfer. There are several methods for preventing erosion corrosion. First of all, some precautions should be taken to prevent wear. Intervention is very important in terms of cost, especially at the design stage. Measures such as wide angle bends, wall thickness of wear-resistant material and corrosion allowance can be taken, especially in applications where the flow direction needs to be changed. The aim of this study was to determine the effect of liquid fluid on erosion corrosion in Ti6Al4V, 304 stainless steel and MgAz91 elbow pipes by using the computer aided and finite element based AnsysWorkbench Explicit Dynamics module. For the design of the elbow pipe, SolidWorks was used for 3D studies. In the analysis of the pipe, the suitability of the pipe for the 3D model was examined. The effect of fluid rotation on the pipe walls and the effect of the pipe material on the flow along the pipe were determined. The standard k-e model based on the velocity-pressure relationship in continuous and steady flow was used for the flow calculations. The flow simulation showed that for all models the flow accumulation after rotation was more concentrated on the opposite walls of the pipe, as expected. The results obtained showed that the deformation in MgAZ91 material had the highest value at 9.14 x 10-8 mm. This situation has been interpreted to mean that it may vary depending on the flow rate automation. Designs on the old designs in the erosion structure of the liquid that occurs in the pipes with a new product design in the analysis design.
EEG based cigarette addiction detection with deep learning
(Int Information & Engineering Technology Assoc, 2024) Cay, Talip; Ölmez, Emre; Altin, Cemil; Tanik, Nermin
In this study, cigarette addiction detection was performed using machine learning techniques with time -frequency feature extraction methods on EEG data collected from 30 different male individuals. Electroencephalography (EEG) data collected from individuals who underwent the Fagerstr & ouml;m Test for Nicotine Dependence (FTND) were labeled as dependent or non-dependent based on their test results. The obtained EEG data were first subjected to Discrete Wavelet Transform (DWT). Then, Power Spectral Density (PSD) analysis and feature extraction processes were performed separately on the outputs obtained from the DWT process. The data obtained from PSD analysis and feature extraction processes were classified using Artificial Neural Networks (ANN). The aim of this study is to achieve higher success rates in cigarette addiction detection by classifying EEG data with machine learning methods after extracting time -frequency features, rather than using traditional methods. In this study, responses to cigarette stimuli were classified using machine learning methods based on EEG graphs. The results revealed that temporal and prefrontal lobes were more distinctive in responses to cigarette stimuli, and success rates were higher in the theta frequency band.
Sustainable production of microcrystalline and nanocrystalline cellulose from textile waste using HCl and NaOH/Urea treatment
(MDPI, 2025) Isitan, Arzum; Pasquardini, Laura; Bersani, Massimo; Gök, Cem; Fioravanti, Simona; Lunelli, Lorenzo; Caglarer, Evren
Bio-nanomaterials are gaining increasing attention due to their renewable and eco-friendly characteristics. Among these, nanocrystalline cellulose (NCC) stands out as one of the most advanced materials for applications in food, healthcare, composite production, and beyond. In this study, NCC was successfully extracted from cotton-based textile waste using a combination of chemical and mechanical methods. The cellulose fibers were first hydrolyzed using a dilute HCl solution, neutralized, and then dried, resulting in microcrystalline cellulose (MCC) with diameters ranging from 7 to 15 mu m and lengths up to 300 mu m (as observed via optical microscopy and scanning electron microscopy, SEM). To achieve nanoscale dimensions, NaOH/urea solution with mechanical treatment was applied, resulting in the successful extraction of NCC in the supernatant, particularly under room-temperature conditions. Dynamic light scattering (DLS) analysis confirmed the presence of nanostructures (average sizes ranging from 120 nm to 750 nm), and atomic force microscopy (AFM) analysis verified the nanoscale range (diameters between 2 and 4 nm and lengths from 200 nm to 1 mu m). Fourier transform infrared (FTIR) spectroscopy revealed the conversion of cellulose I to cellulose II, confirming the successful transformation into NCC. For the first time, NCC was obtained from undyed cotton textile wastes using NaOH/urea treatment after HCl hydrolysis, eliminating the need for pre-treatment and intermediate steps.

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