TR-Dizin İndeksli Yayınlar Koleksiyonu

Permanent URI for this collectionhttps://hdl.handle.net/20.500.12573/396

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3D Sampling of K-Space With Non-Cartesian Trajectories in MR Imaging
(Gazi Univ, Fac Engineering Architecture, 2025) Dundar, Mehmet Sait; Gumus, Kazim Z.; Yilmaz, Bulent
This study presents an innovative approach to 3D k-space sampling in MR imaging using non-Cartesian concentric shell trajectories. The method involves 32 concentric shells of varying radii, allowing for rapid data acquisition through undersampling techniques. Simulations using IDEA software demonstrate that this approach can fill the k-space in less than one second, a significant time reduction compared to traditional FLASH sequences that can take 3-4 minutes. The concentric shell model enhances imaging efficiency by minimizing artifacts and ensuring uniform k-space filling, leading to higher resolution and faster scans. This technique shows promise for clinical applications, particularly in dynamic imaging scenarios such as acute stroke and pediatric radiology, where speed and precision are critical. As illustrated in Figure A, the concentric shell trajectories enable uniform k-space filling, significantly reducing scan times and improving image quality. These results are based on the simulations conducted with IDEA software.
Citation - WoS: 4
Citation - Scopus: 4
All-Polymer Ultrasonic Transducer Design for an Intravascular Ultrasonography Application
(Tubitak Scientific & Technological Research Council Turkey, 2019) Hah, Dooyoung
Intravascular ultrasonography (IVUS), a medical imaging modality, is used to obtain cross-sectional views of blood vessels from inside. In IVUS, transducers are brought to the proximity of the imaging targets so that high-resolution images can be obtained at high frequency without much concern of signal attenuation. To eliminate mechanical rotation rendered in conventional IVUS, it is proposed to manufacture a transducer array on a flexible substrate and wrap it around a cylindrical frame. The transducer of consideration is a capacitive micromachined ultrasonic transducer (CMUT). The whole device needs to be made out of polymers to be able to endure a high degree of bending (radius: 1 mm) Bending of the devices leads to considerable changes in the device characteristics, including resonant frequency and pull-in voltage due to geometrical dimension changes and stress induced. The main purpose of this work is to understand the effect of bending on the device characteristics by means of finite element analysis. Another objective of the work is to understand the relationships between such an effect and the device geometries. It is learned that the bending-induced stress depends strongly on anchor width, membrane thickness, and substrate thickness. It is also learned that resonant frequency and pull-in voltage become lower in most cases because of using a flexible substrate in comparison to those of the device on a rigid substrate. Bending-induced stress increases the spring constant and hence increases resonant frequency and pull-in voltage, although this effect is relatively weaker. For most of the device geometries, pull-in voltage is too high for the polymer material to endure. This is the main drawback of the all-polymer CMUT. In order to meet the design goal of 20 MHz resonant frequency, the membrane radius has to be smaller than 7.7 mu m for a thickness of 3 mu m.
Citation - WoS: 2
Citation - Scopus: 2
Analysis of Optical Gyroscopes With Vertically Stacked Ring Resonators
(Tubitak Scientific & Technological Research Council Turkey, 2021) Hah, Dooyoung
Without any moving part, optical gyroscopes exhibit superior reliability and accuracy in comparison to mechanical sensors. Microring-resonator-based optical gyroscopes emerged as alternatives for bulky conventional Sagnac interferometer sensors, especially attractive for applications with limited footprints. Previously, it has been reported that planar incorporation of multiple resonators does not bring about improvement in sensitivity for a given area because the increase in Sagnac phase accumulation does not outrun the increase of area. Therefore, it was naturally suggested to consider vertical stacking of ring resonators because then, the resonators can share the same footprint. In this work, sensitivity performances of such configurations with vertically stacked microring resonators are analyzed and compared to that of a basic (single-resonator) configuration. Through comprehensive study, it is learned that the sensitivity performance of the devices with vertically-stacked resonators (either with a single bus waveguide or with two bus waveguides) does not exceed that of the basic sensor device (single resonator with one bus waveguide), i.e. the basic structure is yet to be remained as the most efficient configuration.
Apatinib Sensitizes Human Breast Cancer Cells Against Navitoclax and Venetoclax Despite Up-Regulated Bcl-2 and Mcl-1 Gene Expressions
(Kare Publ, 2021) Kavakcioglu Yardimci, Berna; Ozgun Acar, Ozden; Semiz, Asli; Sen, Alaattin
OBJECTIVE Defects in apoptotic cell death which restrict the success of conventional cytotoxic therapies have pivotal roles in a number of pathological conditions including cancer. However, a novel drug class targeting pro-survival Bcl-2 protein family members has been developed with the understanding of the structures and interactions of Bcl-2 proteins. Within this new class, Bcl-2/Bcl-xL inhibitor Navitoclax and Bcl-2 specific inhibitor Venetoclax have been shown to demonstrate strong anticancer activities on several types of cancers. But their low affinity to other anti-apoptotic proteins limits their clinical usage. Here, we investigated the cytotoxic and apoptotic effects of Navitoclax/Venetoclax and their combinations with specific tyrosine kinase inhibitor Apatinib on estrogen receptor (ER)-positive MCF-7 and ER-negative MDA-MB-231 breast cancer cell lines. METHODS MTT assay was used for the evaluation of the inhibition of cancer cell proliferation. ELISA test and Quantitative real-time PCR assay was performed to determine the role of caspase-3, Bak, Bax, Bcl-2, Bcl-xL and Mcl-1 proteins in the inhibition of cell proliferation triggered by the tested agents. RESULTS We found that aggressive MDA-MB-231 cell line was more sensitive to all tested agents. Apatinib significantly enhanced Navitoclax/Venetoclax mediated inhibition of cell viability in both cancer cell lines despite up-regulation in the expression levels of Bcl-2 and Mcl-1 genes. We further demonstrated significant Bak/Bax and caspase-3 expression in less aggressive MCF-7 cells. CONCLUSION Our findings have impacts on Navitoclax/Venetoclax plus Apatinib based therapy for breast adenocarcinoma. On the other hand, further studies should be conducted to elucidate the mechanisms underlying synergistic effects of Navitoclax/Venetoclax plus Apatinib combinations.
Citation - WoS: 2
Citation - Scopus: 3
An Asymptotic-Numerical Hybrid Method for Singularly Perturbed System of Two-Point Reaction-Diffusion Boundary-Value Problems
(Tubitak Scientific & Technological Research Council Turkey, 2019) Cengizci, Suleyman; Natesan, Srinivasan; Atay, Mehmet Tank
This article focuses on the numerical approximate solution of singularly perturbed systems of second-order reaction-diffusion two-point boundary-value problems for ordinary differential equations. To handle these types of problems, a numerical-asymptotic hybrid method has been used. In this hybrid approach, an efficient asymptotic method, the so-called successive complementary expansion method (SCEM) is employed first, and then a numerical method based on finite differences is applied to approximate the solution of corresponding singularly perturbed reaction-diffusion systems. Two illustrative examples are provided to demonstrate the efficiency, robustness, and easy applicability of the present method with convergence properties.
Atatürk’ün Esir Aldığı Yunan General Nikolaos Trikupis ve Talas Üsera Garnizonu
(Sabit Dokuyan, 2023) Karataş, Murat; Metin, Mehmet
After the First World War, especially with the support of England, the Greek army invaded Anatolian lands on the way to realize Megali Idea (Greater Greece). The regular army of the Turkish Grand National Assembly established on the Western Front dealt the final blow to the Greek army with The Great Offensive and the Battle of the Commander –in-Chief. In addition to the Greek soldiers captured in the wars before this victory, many Greek soldiers, as well as the commander –in-chief of the Greek army, General Trikupis, and her entourage were also captured after the said victory. As the number of prisoners increased rapidly after The Great Offensive and the Battle of the Commander –in-Chief, the captive officers were transferred to Afyon, Kırşehir and Kayseri. Other military and civilian prisoners were transferred to different parts of Anatolia. Greek prisoners of war were kept in the prisoner garrisons until the implementation of the document on the mutual release of prisoners signed between the states of Turkey and Greece at the Lausanne Peace Conference. Only Greek Officers remained in Talas Prisoner Garrison, one of these prisoner garrisons. The Talas Prisoner Garrison was inspected twice by international Committee of the Red Cross. The delegation prepared reports on the condition of the prisoners and the garrison. In this study, the captivity of General Trikupis on the battlefield, the Talas Prisoner Garrison and situation of the captive Greek officers staying here, the aid of the Red Crescent Society to the prisoners will be emphasized. The Study was planned to be prepared by making use archival resources, memoirs, newspapers and copyright-reviewed works. © 2023 Elsevier B.V., All rights reserved.
Bor Zengini Amorf Malzemeler
(TUBİTAK, 2020) Durandurdu, Murat
Bu TÜBİTAK 1001 projesi kapsamında, bor zengini farklı amorf malzemeler [B1-xSix, B1-xCx, B1-_x000D_ xOx, ve B1-xLix (0, 5 ≥ � ≥ 0,05)] ab initio moleküler dinamik tekniği kullanılarak sıvı hallerin hızlıca_x000D_ soğutulması sonucu modellenmiş ve bu malzemelerin atomik yapıları, elektronik yapıları ve_x000D_ mekanik özellikleri ayrıntı olarak araştırılmıştır. Bunlara ek olarak, bu malzemelerin bazı_x000D_ oranlarının yüksek basınçtaki davranışları incelenmiştir. Bazı malzemelerde, örneğin BC ve BO_x000D_ malzemelerinde, bor oranının artmasıyla iki boyutlu yapıdan üç boyutlu yapıya geçiş_x000D_ gözlemlenmiştir. Ayrıca yüksek bor oranlarında, B12 icosahedralların oluştuğu bulunmuştur. B12_x000D_ molekülüne ek olarak nano boyutunda B7, B10, B14, B16 kafes moleküllerinin oluşumu bazı_x000D_ malzemelerde gözlemlenmiştir. Modellenen malzemelerin her birinin yarıiletken özelliği gösterdiği_x000D_ fakat yasak band aralığında bor oranına bağlı genel bir eğilim olmayıp dalgalanmaların olduğu_x000D_ bulunmuştur. B12 moleküllerinin oluşumunun malzemelerin mekanik özelliğini dikkate değer bir_x000D_ şekilde etkilediği ve bor oranı yüksek olan malzemelerin daha sert bir özellik gösterdiği_x000D_ bulunmuştur. Yüksek basınç uygulamasıyla, malzemelerin daha yoğun bir amorf yapıya faz_x000D_ geçişişi yaptığı ve malzemeye bağlı olarak, faz geçişlerinin tersinir ya da tersinir olmayan faz_x000D_ geçişleri olduğu gözlemlenmiştir.
A Comparative Study of Unet Variants for Low-Grade Glioma Segmentation in Magnetic Resonance Imaging
(Inonu University, 2025) Guzel, Yasin; Aydin, Zafer
Brain tumors originating from glial cells are pathological entities that significantly impact quality of life and are classified based on their malignancy into low-grade gliomas (LGGs) and high-grade gliomas (HGGs). While the more aggressive HGGs have been extensively studied, LGGs are of critical importance for early diagnosis due to their potential progression to HGGs if left untreated. This has driven researchers to develop methods for the rapid and consistent diagnosis of LGGs. In this study, three models—UNet, Transformer UNet, and Super Vision UNet—were comparatively evaluated for the automatic segmentation of LGGs using magnetic resonance imaging (MRI) data. Multimodal MRI scans from 110 patients, retrieved from The Cancer Imaging Archive (TCIA), were used to train the models. Performance was evaluated using Dice Coefficient, Tversky Index, and Intersection over Union (IoU) metrics. The Super Vision UNet achieves the highest Dice (0.9115) and Tversky (0.9154) scores, while the Transformer UNet attains the highest IoU (0.8789). Both advanced models demonstrate superior segmentation performance with lower loss values compared to the conventional UNet. Visual outputs indicate that the modern architectures delineate tumor contours with greater precision. These results highlight the effectiveness and reliability of contemporary UNet-based and Transformer-based architectures in segmenting complex tumor structures such as LGGs. Integrating these models into clinical decision support systems holds promise for enhancing the speed and accuracy of the diagnostic process. © 2025 Elsevier B.V., All rights reserved.
Citation - Scopus: 5
A Comparative Study to Estimate the Mode I Fracture Toughness of Rocks Using Several Soft Computing Techniques
(Murat Yakar, 2023) Köken, E.; Kadakci Koca, Tümay
Fracture toughness is an important phenomenon to reveal the actual strength of fractured rock materials. It is, therefore, crucial to use the fracture toughness models principally for simulating the performance of fractured rock medium. In this study, the mode-I fracture toughness (KIC) was investigated using several soft computing techniques. For this purpose, an extensive literature survey was carried out to obtain a comprehensive database that includes simple and widely used mechanical rock parameters such as uniaxial compressive strength (UCS) and Brazilian tensile strength (BTS). Several soft computing techniques such as artificial neural network (ANN), adaptive neuro-fuzzy inference system (ANFIS), gene expression programming (GEP), and multivariate adaptive regression spline (MARS) were attempted to reveal the availability of these methods to estimate the KIC. Among these techniques, it was determined that ANN presents the best prediction capability. The correlation of determination value (R2) for the proposed ANN model is 0.90, showing its relative success. In this manner, the present study can be declared a case study, indicating the applicability of several soft computing techniques for the evaluation of KIC. However, the number of samples for different rock types should be increased to improve the established predictive models in future studies. © 2023 Elsevier B.V., All rights reserved.
Citation - WoS: 1
Citation - Scopus: 1
The Comparison of Fragility Curves of Moment-Resisting and Braced Frames Used in Steel Structures Under Varying Wind Load
(Turkish Chamber Civil Engineers, 2025) Ozalp, Abdulkadir; Gokdemir, Hande; Ciftci, Cihan
In this study, the performance of two different steel structure types (moment-resisting frame and braced frame) under wind loading was compared by addressing the fragility curves of these structure types. To perform this comparison, the dimensions of the members of these structural systems were first determined. Then, nonlinear static pushover analyses were conducted to assess the performance levels of each frame type. After applying these analyses, time-history analyses were performed with 100 different wind loads for each varying equivalent mean wind speed. Afterwards, the probability of exceeding the predetermined structural performance limits of the structure types was determined using Monte Carlo simulation method. Finally, the results of the simulation method were used to adapt the maximum likelihood estimation method to obtain the fragility curves of the structures. To conclude, it has been revealed that the material cost of the structure doubles when diagonal elements are used, but the wind speed required for a 100% collapse probability to occur in the braced frame is twice as high compared to the moment-resisting frame.
Citation - Scopus: 1
Comparison of Mechanical and Physical Properties of Screed With and Without Expanded Polystyrene (EPS) Particles
(Yildiz Technical University, 2022) Kiliç, Fikret Merih; Yorulmaz, Hediye; Özuzun, Sümeyye; Durak, Uğur; İLkentapar, Serhan; Karahan, Okan; Atis, C. D.
In this study, in order to observe the mechanical and physical properties of ordinary screed, sandy-lightweight screed and lightweight screed samples, expanded polystyrene (EPS) was used as fine aggregate and lightweight screed systems were produced by replacing sand at 100%, 50% and 0%. Samples of cement dosages of 250, 300, 350 kg/m3 were produced for lightweight screeds, sandy-lightweight screeds and ordinary screeds. Unit weight, water absorption capacity, flexural strength, compressive strength, fire resistance, abrasion and thermal conductivity tests were performed on the produced screed systems. As a result of the research, it was determined that as EPS ratio increases in screed system; unit weights decreased, water absorption rates increased. Besides, the flexural and compressive strengths, fire and abrasion resistance are also decreased. However, it was observed that the thermal conductivity coefficient reduced with the increment of EPS particles in the screed. In normal, sandy-lightweight and lightweight screeds, it was determined that as the cement dosage increased; the unit weights, flexural and compressive strengths, fire and abrasion resistance increased, water absorption capacity and the thermal conductivity coefficient decreased. © 2022 Elsevier B.V., All rights reserved.
Citation - WoS: 1
Citation - Scopus: 2
Complementary Medicines Used in Ulcerative Colitis and Unintended Interactions With Cytochrome P450-Dependent Drug-Metabolizing Enzymes
(Tubitak Scientific & Technological Research Council Turkey, 2022) Sen, Alaattin
Ulcerative colitis (UC) is an idiopathic, chronic inflammatory disease with multiple genetic and a variety of environmental risk factors. Although current drugs significantly aid in controlling the disease, many people have led to the application of complementary therapies due to the common belief that they are natural and safe, as well as due to the consideration of the side effect of current drugs. Curcumin, cannabinoids, wheatgrass, Boswellia, wormwood and Aloe vera are among the most commonly used complementary medicines in UC. However, these treatments may have adverse and toxic effects due to unintended interactions with drugs or drug-metabolizing enzymes such as cytochrome P450s; thus, being ignorant of these interactions might cause deleterious effects with severe consequences. In addition, the lack of complete and controlled long-term studies with the use of these complementary medicines regarding drug metabolism pose additional risk and unsafety. Thus, this review aims to give an overview of the potential interactions of drug-metabolizing enzymes with the complementary botanical medicines used in UC, drawing attention to possible adverse effects.
Comprehensive Prediction of FBN1 Targeting Mirnas: A Systems Biology Approach for Marfan Syndrome
(Galenos Publishing House, 2025) Orhan, M.E.; Demirci, Y.M.; Saçar Demirci, M.D.S.
Objective: Marfan syndrome (MFS) is a genetic connective tissue disorder primarily caused by mutations in the FBN1 gene. Emerging evidence highlights the regulatory role of microRNAs (miRNAs) in modulating gene expression in MFS, but a systematic investigation into miRNAs targeting FBN1 is lacking. This study aimed to comprehensively identify miRNAs interacting with the FBN1 transcript to reveal potential molecular regulators and therapeutic targets. Methods: Human miRNA sequences were retrieved from miRBase (Release 22.1), and the canonical FBN1 transcript (RefSeq: NM_000138.5) was used for target prediction. Computational interaction analysis was conducted using the psRNATarget server with stringent parameters to detect potential miRNA binding sites. Expression profiles and disease associations of the top candidate miRNAs were further investigated through database integration and literature review. Results: Out of 2656 human mature miRNAs analyzed, 251 were predicted to bind FBN1, with the hsa-miR-181 family exhibiting the highest number of predicted interactions. Evidence from the literature highlighted dysregulation of hsa-miR-181 expression in MFS patients, suggesting a functional role in disease pathophysiology. Conclusion: This study identifies key members of the hsa-miR-181 family as post-transcriptional regulators of FBN1, offering new insights into miRNA-driven mechanisms in MFS. These findings support the potential of RNA-based diagnostics and therapeutic strategies targeting miRNA-FBN1 interactions. ©Copyright 2025 The Author.
Cytotoxic and Cytostatic Effects of Targeting mTOR and Hedgehog Pathways in Acute Myeloid Leukemia
(Istanbul Univ, 2022) Cicek, Enes; Kucuktas, Fulya Mina; Yenigul, Munevver; Akcok, Emel Basak Gencer
Objectives: Acute myeloid leukemia (AML) is a highly aggressive heterogeneous hematopoietic malignancy characterized by a rapid and abnormal proliferation of immature myeloid leukemia cells in the bone marrow and peripheral blood. Aberrant alterations in signal transduction pathways are strongly associated with the progression of AML. This study aimed to investigate cell viability and the cell cycle in AML cells by targeting the Hedgehog and mTOR signaling pathways with rapamycin and GANT61. Materials and Method: The antiproliferative effect of rapamycin and GANT61 was assessed by the MTT cell viability assay in two AML cell lines: CMK and MOLM-13. The effect of the inhibitors on cell-cycle distribution was determined using propidium iodide staining and measured with flow cytometry. Results: Rapamycin, an mTOR inhibitor, and GANT61, a Gli-1 inhibitor, decreased the cell proliferation of CMK and MOLM-13 cells. The IC20 values, which is the drug concentration that inhibits cell growth by 20%, were combined and administered to the cells. The results show the drugs to have a combinatorial inhibitory effect on CMK cells but not on MOLM-13 cells. In addition, the combination of drugs arrested the cells during the G0/G1 phase. Conclusion: This study suggests a novel combination therapy approach for AML via mTOR and Hedgehog signaling pathway inhibition using rapamycin and GANT61, respectively. It also suggest further studies be performed to reveal the mechanism of action.
Citation - Scopus: 2
Determining Datum Temperature and Apparent Activation Energy: An Approach for Mineral Admixtures Incorporated Cementitious Systems
(Tulpar Academic Publishing, 2024) Atasever, Muhammet; Tokyay, Mustafa
The maturity method is used to predict the strength of concrete by monitoring its temperature history. Accuracy of maturity method relies on the dependable determination of the datum temperature and the apparent activation energy. The current study introduces a new approach, complementing those in ASTM C1074-11, for determining the datum temperature and apparent activation energy. The experimental study involved using two different mineral additives to portland cement at 6%, 20%, and 35% replacement amounts. The mortars were then cured at temperatures of 5, 20, and 40 °C, and their strengths were determined. Subsequently, the datum temperatures and apparent activation energies for these mixtures were calculated using both the proposed approach and the alternatives from ASTM C1074-11. Strength estimations were conducted in conjunction with commonly used maturity functions. The results indicate that the proposed approach determines the datum temperature and apparent activation energy reliably for mineral admixture-incorporated mortars. Furthermore, the predicted strengths, derived from the datum temperature and apparent activation energy calculated through the proposed approach, show a closer alignment with the experimental results when applying the Nurse-Saul and Hansen-Pedersen equations, as opposed to the Rastrup and Weaver-Sadgrove models. © 2024 Elsevier B.V., All rights reserved.
Citation - Scopus: 1
Düzce Kent Merkezi Zeminlerinin Sıvılaşma Potansiyelinin Değerlendirilmesi
(TMMOB - Jeoloji Muhendisleri Odasi jmo@jmo.org.tr, 2019) Akin, Muge K.
Soil liquefaction is one of the ground deformations occurred during an earthquake which may cause serious damages such as settlement and tilting of structures due to loss of bearing capacity of foundations. Düzce and its surrounding settle on a plain which consists of silty and sandy layers with shallow groundwater level. Besides, the North Anatolian Fault Zone is a major seismic source which is capable of producing large magnitude earthquakes. All these data point out that the ground deformations like liquefaction and lateral spreading may occur during a probable large earthquake around Düzce and its close vicinity. In this study, the geotechnical data of 40 boreholes drilled to determine the local ground conditions and the groundwater level in Düzce were considered. Based on the field studies, it was aimed to evaluate the liquefaction potential considering the fact that the groundwater level is shallow as well as the subsurface soil is composed of loose alluvium. Liquefaction Potential Index (LPI) and Liquefaction Severity Index (LSI) methods were taken into account and the liquefaction potential of Düzce province was determined and mapped with respect to various earthquake scenarios in GIS environment. These maps are compared on the basis of different scenarios. Accordingly, it is concluded that the liquefaction potential is high-very high in the south and south-eastern sections of the study area where the construction of new residential buildings progressively continues. © 2019 Elsevier B.V., All rights reserved.
Effects of Dry Particle Coating With Nano-and Microparticles on Early Compressive Strength of Portland Cement Pastes
(Tulpar Academic Publishing, 2021) Yorulmaz, Hediye; Özuzun, Sümeyye; Uzal, Burak; İLkentapar, Serhan; Durak, Uğur; Karahan, Okan; Atis, C. D.
It is known that nano-and microparticles have been very popular in recent years since their advantages. However, due to the very small size of such materials, they have very high tendency to agglomeration particularly for nanoparticles. Therefore, it is critical that they are properly distributed in the system to which they are added. This paper investigated the effects of dry particle coating with nano-and microparticles to solve the agglomeration problem. For a clear evaluation, paste samples were preferred to detemine the compressive strength. Nano-SiO2 and nano-CaCO3, microCaCO3 and micro-SiO2, also known as silica fume, were selected as particulate additives. It was studied by the addition of various percentages (0.3, 0.7, 1, 2, 3 and 5%) of nano-and microparticles in cementitious systems, replacing cement by weight with and without dry particle coating. Dry particle coating was made by using a highspeed paddle mixer. Portland cement and additive particles were mixed at 1500 rpm for 30 seconds in high-speed powder mixer designed for this purpose. The 3-day compressive strength of the cement-based samples to which particles were added at the specified rates was determined and the effect of the dry particle coating on the early strength was investigated. According to the results, it was observed that the production of paste with the dry particle coating technique gave higher compressive strength compared to the production of paste directly in early period. Especially with dry particle coating, compressive strength increased more than 100% in paste samples containing 0.3% nano-SiO2 compared to direct addition without coating. © 2024 Elsevier B.V., All rights reserved.
Citation - Scopus: 1
Electricity Load Forecasting Using Deep Learning and Novel Hybrid Models
(Sakarya University, 2022) Sutcu, Muhammed; Şahi̇n, Kübra Nur; Koloğlu, Yunus; Çelikel, Mevlüt Emirhan; Gulbahar, Ibrahim Tümay
Load forecasting is an essential task which is executed by electricity retail companies. By predicting the demand accurately, companies can prevent waste of resources and blackouts. Load forecasting directly affect the financial of the company and the stability of the Turkish Electricity Market. This study is conducted with an electricity retail company, and main focus of the study is to build accurate models for load. Datasets with novel features are preprocessed, then deep learning models are built in order to achieve high accuracy for these problems. Furthermore, a novel method for solving regression problems with classification approach (discretization) is developed for this study. In order to obtain more robust model, an ensemble model is developed and the success of individual models are evaluated in comparison to each other. © 2025 Elsevier B.V., All rights reserved.
Enlightening the Molecular Mechanisms of Type 2 Diabetes With a Novel Pathway Clustering and Pathway Subnetwork Approach
(Tubitak Scientific & Technological Research Council Turkey, 2022) Bakir-Gungor, Burcu; Yazici, Miray Unlu; Goy, Gokhan; Temiz, Mustafa
Type 2 diabetes mellitus (T2D) constitutes 90% of the diabetes cases, and it is a complex multifactorial disease. In the last decade, genome-wide association studies (GWASs) for T2D successfully pinpointed the genetic variants (typically single nucleotide polymorphisms, SNPs) that associate with disease risk. In order to diminish the burden of multiple testing in GWAS, researchers attempted to evaluate the collective effects of interesting variants. In this regard, pathway-based analyses of GWAS became popular to discover novel multigenic functional associations. Still, to reveal the unaccounted 85 to 90% of T2D variation, which lies hidden in GWAS datasets, new post-GWAS strategies need to be developed. In this respect, here we reanalyze three metaanalysis data of GWAS in T2D, using the methodology that we have developed to identify disease-associated pathways by combining nominally significant evidence of genetic association with the known biochemical pathways, protein-protein interaction (PPI) networks, and the functional information of selected SNPs. In this research effort, to enlighten the molecular mechanisms underlying T2D development and progress, we integrated different in silico approaches that proceed in top-down manner and bottom-up manner, and presented a comprehensive analysis at protein subnetwork, pathway, and pathway subnetwork levels. Using the mutual information based on the shared genes, the identified protein subnetworks and the affected pathways of each dataset were compared. While most of the identified pathways recapitulate the pathophysiology of T2D, our results show that incorporating SNP functional properties, PPI networks into GWAS can dissect leading molecular pathways, and it could offer improvement over traditional enrichment strategies.
Ethyl Vinyl Acetate (EVA) Composites With Nanoclays and Boric Acid: Thermal and Mechanical Properties
(Turkish Energy, Nuclear and Mining Research Agency, 2025) Erdem, İlker; Kapçı, Mehmet Fazıl; Avcı, Şeyma
Polimerler pek çok uygulamada kullanılmaktadırlar fakat yanabilir olmaları sorun teşkil etmektedir. Polimerlere yanma dayanımı seramikler gibi (oksitler, hidroksitler, killer, vb.) inorganik malzemeler kullanılarak kazandırılabilir. Bu katkıların ilavesi polimer-inorganik kompozitlerin mekanik özelliklerini de değiştirebilir ki kompozit hazırlamada bu da dikkate alınmalıdır. Bu çalışmada etil vinil asetata (EVA) iki faklı nano-kil (ağırlıkça 20/100 oranına kadar) ve borik asit eklenerek polimerin yanmasında olası gecikme araştırılmıştır. Nano-kil ve BA ilavesinin etkisini belirlemek için saf polimer ve polimer-inorganik kompozitler için mekanik özellikler de belirlenmiştir. Hazırlanan nanokompozitlerin kimyasal yapıları (FT-IR, XRD), ısıl özellikleri (TGA), mekanik özellikleri (çekme testi) ve yanma davranışları değerlendirilmiştir. En yüksek nano-kil içeriğine sahip NC 1.4 örneği en uzun sürede yanmıştır. NC 2 örneğinin diğer örneklerden daha yüksek gerilim dayanımına ve Young katsayısına sahip olduğu bulunmuştur. Nano-killerdeki organik yüzey dönüştürücüler ve BA ilavesi nano-kil/EVA kompozitlerinin ısıl ve mekanik özellikleri üzerinde etkili olmuştur.

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