PubMed İndeksli Yayınlar Koleksiyonu
Permanent URI for this collectionhttps://hdl.handle.net/20.500.12573/397
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Article Time Distributed Classification of Alzheimer’s Disease on MRI Scans(John Wiley and Sons Ltd, 2026) Dundar, Mehmet Sait; Yilmaz, BulentThe diagnosis of Alzheimer's disease (AD) has progressively depended on sophisticated neuroimaging methods alongside cognitive assessments. This study combines volumetric feature analysis with computational modeling techniques, focusing on spatial and temporal analysis, to categorize individuals as cognitively normal (CN), mild cognitive impairment (MCI), or AD using magnetic resonance imaging (MRI) data. In the initial phase, volumetric changes, comprising cortical thickness, white matter, grey matter, cerebrospinal fluid, and total intracranial volume, were derived from the Alzheimer's Disease Neuroimaging Initiative (ADNI) dataset utilizing the CAT12 toolbox in statistical parametric mapping (SPM). Linear regression was utilized on these variables over time to create slopes that reflect volumetric change rates, which then served as inputs for machine learning classifiers. The slopes of cortical thickness exhibited the greatest classification accuracy, reaching 82.5% with a random forest model for differentiating AD from CN individuals. During the second phase, a deep learning methodology was utilized, relying solely on the MRI scans and excluding the outcomes from the first phase. A pre-trained 3D ResNet-101 convolutional neural network (CNN) model extracted spatial characteristics from MRI volumes, whereas long short-term memory (LSTM) networks recorded temporal dynamics across subsequent annual scans. This hybrid CNN-LSTM design markedly improved classification performance, attaining 96.7% accuracy for AD against CN and enhancing the distinction of MCI cases. Nonetheless, discrepancies in MCI categorization were chiefly ascribed to the restricted access to annual MRI data and the model's pre-training on CN and AD cohorts. These findings highlight the potential of integrating volumetric statistical analysis with deep learning for automated AD categorization. This work enhances neuroimaging diagnostic methods by utilizing both spatial and temporal MRI data, enabling early diagnosis and better evaluation of disease development.Article Radar Resolution Enhancement Based on Burg-Aided MIMO-DBS and Burg-Aided MIMO-SAR †(MDPI, 2026) Bekar, Muge; Bekar, Ali; Baker, Christopher John; Gashinova, Marina; Pirkani, AnumAutonomous systems require sensors that provide high-resolution imagery in adverse lighting and weather conditions for advanced situational awareness. In this regard, radars are a mandatory component of autonomous systems. Although Multiple-Input Multiple-Output (MIMO) radars provide high angular resolution beyond that of their actual physical dimension, much higher cross-range resolutions are required, especially in traffic congested areas, to differentiate and recognize closely positioned targets. The motion of the MIMO radar platform can be exploited to obtain higher cross-range resolution in the off-boresight direction, using Synthetic Aperture Radar (SAR) and Doppler Beam Sharpening (DBS) techniques, but improvements in the boresight direction, the most crucial direction for path planning, require the use of super-resolution techniques. This paper proposes a technique that combines the Burg algorithm with MIMO-SAR and MIMO-DBS radar data to enhance the cross-range resolution in the boresight direction and to achieve further enhanced cross-range resolution in off-boresight directions. The proposed technique is applied to both frequency domain and time domain data in back-projection (BP) and DBS image formation processing. A comprehensive comparison is made, with evaluation of corresponding performance and operational complexity. The performance of the technique is validated through simulation, lab-based and real-world experiments at a frequency of 77 GHz.Article A Novel Dental Implant Nut System Designed to Enhance Primary Stability: Mechanical and Finite Element Analysis(Wiley, 2026) Demirbaş, Ahmet Emin; Bal, Burak; Alkan, Alper; Şahin, Mert; Soylu, EmrahPurpose: The present study aimed to evaluate, in a preclinical setting, the biomechanical behavior and mechanical performance of a newly developed dental implant nut system designed to address primary stability challenges in the severely resorbed posterior maxilla. Materials and Methods: The evaluation consisted of two complementary stages: an in vitro mechanical experiment and a finite element analysis (FEA). In the experimental phase, polyurethane jaw models simulating a severely atrophic posterior maxilla with approximately 1 mm residual bone height were used. Four groups were prepared: single implant without nut, single implant with nut, double implant without nut, and double implant with nut (n = 10 per group). Primary stability was measured using resonance frequency analysis (RFA) with an Osstell device. In the computational phase, three-dimensional finite element models were constructed from cone-beam computed tomography (CBCT) data of the same configuration to evaluate detachment forces and stress distribution within the bone-implant complex under vertical loading. Results: In single-implant models, mean implant stability quotient (ISQ) values increased from 10.91 +/- 7.35 to 18.27 +/- 7.11 after nut application. In double-implant models, ISQ values increased from 11.13 +/- 4.14 to 19.24 +/- 4.24 (p < 0.05). FEA results revealed that the detachment force increased from 16.5 to 20.33 N in single-implant models and from 15 to 22.3 N in double-implant models. Compressive stresses on the bone were lower in nut-supported configurations, indicating a more favorable load distribution. Conclusion: The nut system was associated with increased implant primary stability and a more favorable stress distribution under the conditions of this preclinical study. These findings should be interpreted as preliminary biomechanical evidence, as no in vivo or clinical validation was performed. Therefore, this design may be considered a mechanical stabilization concept that warrants further investigation through in vivo and clinical studies.Article A Novel ELF4 Gene Variant Disrupts T and NK Cell Function in a Patient with Immune Thrombocytopenia (ITP)(Springer Basel AG, 2026) Kendirli, Perihan Kader; Gök, Veysel; Eken, Ahmet; Özcan, Alper; Erdem, Şerife; Kısaarslan, Ayşenur Paç; Kayhan, EdaObjective and design In this report, we identified a novel hemizygous ELF4 variant (c.1822G > C; p.Gly608Arg) in an adolescent male with chronic immune thrombocytopenia (ITP) and performed functional immunologic characterization. Materials and methods Peripheral blood mononuclear cells (PBMCs) of the patient and age-matched controls were characterized by flow cytometry with respect to T cell phenotype, activation, proliferation and NK cell cytotoxicity. Results The p.Gly608Arg substitution affects a highly conserved residue in the C-terminal regulatory domain of ELF4 and is predicted to be damaging. Immunophenotyping showed an expanded CD8(+) T-cell compartment, an inverted CD4/CD8 ratio, reduced na & iuml;ve T-cell populations, and accelerated acquisition of memory-like phenotypes upon activation. Both CD4(+) and CD8(+) T cells displayed increased proliferation following TCR stimulation, consistent with impaired ELF4-dependent regulation of effector T-cell expansion. NK cells exhibited reduced granzyme B and perforin expression and markedly diminished cytotoxicity against K562 targets, indicating defects in maturation and effector function. Conclusions These findings suggest that the identified ELF4 variant is associated with combined T- and NK-cell dysfunction. This case expands the clinical spectrum of Deficiency in ELF4, X-linked and underscores the relevance of evaluating ELF4 mutations in patients with unexplained cytopenias accompanied by dysregulated lymphocyte activation and impaired cytotoxic responses.Article Tooth Decay Promotes Senescence in Dental Pulp Stem Cells, Modifying Their Biological and Proteomic Profiles(Wiley, 2026) Durukan, Sebahat Melike; Tez, Banu Cicek; Ozcan, Servet; Simsek, Ahmet; Al-Sammarrie, Sura Hilal Ahmed; Gunaydin, Zeynep; Acar, Mustafa BurakDental caries is a prevalent oral health problem that significantly reduces an individual's quality of life; although, it can be effectively managed through restorative treatments. Even in cases where the caries does not reach the pulp, released microbial products from the lesion can still penetrate the pulp chamber, potentially inducing stress on pulp cells. In this study, we conducted a comparative analysis of the biological and proteomic profiles of dental pulp stem cells (DPSCs) isolated from clinically asymptomatic teeth with dentinal caries that had not reached the pulp and isolated from healthy teeth. Following biological evaluations, we examined proteomes of these DPSCs by conducting a shotgun proteomics approach. Our findings show that DPSCs from decayed teeth exhibit a significantly higher proportion of senescent cells. Proteomic profiling revealed upregulation of inflammatory signaling, extracellular matrix remodeling, and senescence-associated secretory phenotype (SASP) related proteins. Additionally, we observed an upregulation in the expression of proteins associated with extracellular matrix (ECM) remodeling and components of the SASP, which are hallmarks of the senescence process. The study reveals that DPSCs can be affected by stress from carious lesions, even when the pulp appears clinically intact. Senescence and inflammatory response in these affected cells may have deleterious effects on other tissues within the organism. Consequently, restorative treatments should consider targeting not only the decayed tissue but also the senescent cells within the pulp that may have been affected by the stress induced by caries.Article Performance Evaluation of Multi-Modal Radar Signal Processing in Dense Co-Existent Environments(MDPI, 2026) Norouzian, Fatemeh; Bekar, Muge; Bekar, Ali; Gashinova, Marina; Pirkani, AnumThe wide-scale deployment of radars, distributed across a platform and across multiple platforms for reliable 360 degrees situational awareness (SA), introduces the challenge of radar interference. Interference can broadly be categorised as self-interference (between radars mounted on the same platform) and mutual interference (signals received from radars on other platforms). Both types of interference impede the reliability of SA delivered by such systems, particularly in dense environments where numerous radars operate simultaneously within the same frequency band. This work presents a comprehensive evaluation of a multi-modal beamforming approach that combines unfocused synthetic aperture radar with the traditional Multiple-Input, Multiple-Output beamformer to enhance radar resolution and suppress interference. Additionally, various aspects of sensor configurations defining hardware and software capabilities of state-of-the-art radars are discussed, and a systematic analysis of signal-to-interference-plus-noise ratio at each step of the processing is presented. Extensive simulations and experimental results in both automotive and maritime environments are shown to validate the effectiveness of the proposed approach.Article Immune-Driven Mechanisms in Idiopathic Intracranial Hypertension: A Critical Synthesis(Walter de Gruyter GmbH, 2026) Tuzun, Erdem; Yetimler, BerrakIdiopathic intracranial hypertension (IIH) is increasingly recognised as a complex disorder characterized by elevated intracranial pressure (ICP), with evidence suggesting contributions from dysregulated cerebrospinal fluid (CSF) dynamics as well as metabolic, endocrine, and neurovascular mechanisms. IIH predominantly affects women of reproductive age who are living with obesity. Clinically, IIH may be asymptomatic or present with severe headaches, visual disturbances, and papilledema, with a risk of visual impairment in some untreated or refractory cases. Although the etiopathogenesis of IIH remains unclear, emerging evidence from metabolic and immunological studies suggests that immune-mediated mechanisms may contribute to disease pathophysiology. In this review, we synthesize current literature on the potential contribution of the immune system to IIH, integrating findings across obesity-associated inflammation, circulating cytokine profiles, comorbid inflammatory and autoimmune conditions, and markers of neuroglial stress and injury. We summarize converging data suggesting that IIH may, at least in part, be influenced by a pro-inflammatory milieu that affects CSF dynamics. While available studies highlight intriguing immunological signals, the underlying mechanistic pathways remain poorly resolved. Larger, longitudinal, and mechanistically grounded investigations are needed to clarify causality, identify relevant immune subtypes, and determine whether immune modulation may offer therapeutic opportunities in IIH.Article Parametric Study on the Behavior of CFRP-Strengthened Reinforced Concrete Deep Beams with Cut Circular Web Openings in Shear Spans(Nature Portfolio, 2026-02-17) Yagmur, ErenWeb openings in reinforced concrete deep beams are often necessary for functional purposes but substantially reduce structural performance. Carbon fiber-reinforced polymer (CFRP) strengthening is commonly employed to mitigate these effects. Previous studies typically examined openings in regions without stirrups or assumed closed stirrup configurations, overlooking the frequent stirrup damage that occurs in practice due to the high shear reinforcement in deep beams. In this study, three specimens from a prior experimental program were modeled in ABAQUS, and the numerical results were validated against experimental data. Openings of varying diameters were introduced by cutting reinforcements, and the beams were subsequently strengthened with CFRP laminates, and a parametric study was conducted. Results showed that increasing opening diameter markedly reduces load-carrying capacity and energy absoption, while thicker CFRP laminates partially restore performance. For example, a 300 mm opening in a 500 mm high unstrengthened beam reduced load capacity by 56% and energy absorption by 87%. Even when the opening diameter was less than one-third of the beam height, 1.8 mm CFRP laminates provided only limited improvement. Deep beam performance was strongly influenced by web opening size, and the effectiveness of CFRP strengthening was limited when stirrup integrity was compromised.Article Bi-Allelic Variants in OLA1 Cause a Neurodevelopmental Disorder with Joint Hypermobility(Cell Press, 2026-04) Cevik, Sebiha; Alzahrani, Fatema; Sezer, Abdullah; AlAbdi, Lama; Demir, Zanyar; Abdullah, Nor Linda; Alkuraya, Fowzan S.Cytoskeletal organization, cell adhesion, and cell motility are key to neuronal development and functional synapses. Obg-like ATPase 1 (OLA1) regulates cell-matrix adhesion by modulating focal adhesion kinase (FAK) levels, therefore regulating cytoskeletal dynamics and cell motility. To date, however, no Mendelian phenotypes in humans have been linked to OLA1. We identified fourteen individuals from nine families in whom hypermobility-neurodevelopmental disorder with distinct facies is linked to bi-allelic deleterious variants in OLA1. The hypermobility phenotype evoked a diagnosis of Ehlers-Danlos syndrome (EDS) in some affected individuals. The loss-of-function nature of these variants is confirmed in proband-derived fibroblasts, recapitulating the impaired migration and proliferation phenotype previously described in OLA1-deficient cells. To explore the pathogenesis of abnormal neurodevelopment in our probands, we investigated neurons derived from proband fibroblasts and identified impaired adhesion and cytoskeletal control. Modeling ola-1 deficiency in C. elegans revealed reduced neurite numbers compared to the wild type. Additionally, transcriptomic analysis of the ola-1-deficient worms suggested that dysregulation of key signaling pathways results in suppression of microtubule dynamics and axon regrowth, ultimately crippling the regenerative competence of mutant animals compared to wild-type controls. Our results support an autosomal-recessive OLA1-related hypermobility-neurodevelopmental disorder and suggest that dysregulation of key signaling pathways results in the suppression of microtubule dynamics as a potential underlying mechanism.Article Views on Climate Change, Climate Action and Mental Health, in Young People with and without Existing Depression Symptoms: A Qualitative Study(Elsevier, 2026-01) Kaya, M. Siyabend; Hawkins, Ed; McCabe, CiaraBackground: Youth mental health is in crisis. Climate change has the potential to tip more young people into depression and anxiety. Knowing how young people with and without depression symptoms view climate change could guide interventions to mitigate against climate induced mental health issues. Materials and Methods: We carried out in-depth, semi-structured interviews with (N = 27) young people aged 18-25 (M-age = 20.3 years). Participants were grouped as healthy controls (C, N = 16, < 16 score on Mood and Feelings Questionnaire, MFQ) or had high depression symptoms (HD, N = 11, >= 27, MFQ). Using thematic analysis, we explored participants views on climate change, climate action, climate messaging, climate agency and mental health. Results: From the interviews, eight key themes emerged: (1) Negative environmental events - Climate change was understood as ranging from weather changes to natural disasters. (2) Mental health impacts - Most participants reported increased anxiety and depression, with the HD group being more pessimistic about climate change prevention. (3) Benefits of action - Focus on individual efforts. (4) Non-disruptive vs. disruptive actions - Preference for non-disruptive solutions. (5) Hope and Fear in climate messaging - balance is needed. (6) Local and global action - Emphasis on combining both approaches. (7) Leadership - Responsibility placed on politicians, institutions, and environmentalists. (8) Shared responsibility - Families, educators, governments, and celebrities all have a role in climate action. Conclusion: These findings offer valuable insights into the perspectives of young people with and without existing symptoms of depression. Notably, identifying differences-such as varying levels of climate pessimism-based on depression status highlights the importance of climate communication strategies that not only effectively address climate change but also safeguard youth mental health. This is important as those with existing depression symptoms may be more vulnerable to the psychological impacts of climate change.