Scopus İndeksli Yayınlar Koleksiyonu
Permanent URI for this collectionhttps://hdl.handle.net/20.500.12573/395
Browse
225 results
Search Results
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 Spatial Proximity and Accessibility Patterns of X-Minute Cities(Elsevier Ltd, 2026) Östh, John; Türk, Umut; Kourtit, Karima; Nijkamp, PeterThe 15-minute city concept has gained prominence in urban planning as a framework linking proximity, mobility, and quality of life at the intra-urban scale. An open question is whether this concept remains meaningful when applied to spatially connected urban regions or national urban systems. To address this issue, the new X-minute city concept allows proximity thresholds to vary with spatial context, mobility conditions, and service distribution. This paper develops an operational framework with the aim to examine and highlight spatial accessibility patterns from an X-minute city perspective, using the relatively urbanized area of the Netherlands as a national-scale case study. Accessibility is analyzed at the building level using OpenStreetMap data and a combination of object-based k-nearest-neighbor measures, distance-decay functions, inequality metrics, Average Nearest Neighbor analysis, and quantile regression. Concepts from central place theory are employed as an interpretive lens to understand service clustering and accessibility patterns, rather than as a formal model to be tested. The results show pronounced spatial disparities in accessibility between urban and rural areas, as well as substantial variation within cities. Major urban centers such as Amsterdam, Rotterdam, and Utrecht exhibit high accessibility levels due to dense service provision, while peripheral and rural areas face systematically lower accessibility. Next accessibility outcomes also differ sharply across population groups. Elderly residents and groups reliant on walking experience the highest levels of inequality, with accessibility distributions remaining highly uneven at short-distance thresholds. Cycling expands the range of effective activity spaces and reduces inequality, but does not offset structural disadvantages in areas with sparse service provision. The findings point to the limits of uniform proximity targets and reveal the need for context-sensitive accessibility planning that explicitly accounts for service distribution, mobility constraints, and population heterogeneity within national urban systems.Article Institutions and Bank Intermediation: The Joint Role of State Capacity and Civil Liberties(Wiley, 2026) Raz, Arisyi F.; Gokmen, SeyitWe examine the effects of state capacity and civil liberties on bank intermediation, measured by banks' ability to generate liquidity in the economy. Theory suggests that a strong state that upholds civil liberties can create institutions that promote economic activity, including the development of its banking sector. We investigate this hypothesis by testing a possible channel: confidence in the banking system. Democracies tend to increase trust in the banking system by reforming institutions, while autocracies frequently rely on cronyism. Over the long run, trust in the banking system promotes banking development and intermediation in democracies, whereas cronyism and the risk of expropriation by autocrats undermine the potential for banking sector advancement in autocracies, despite having a trustworthy banking system. Our findings provide evidence in support of this channel, offering new insights into the role of political institutions in the banking sector.Article Functional Characterization of Loss of RNF43 Reveals Neuronal Defects in a Caenorhabditis Elegans Model(MDPI, 2026) Kazan, Hasan Huseyin; Turkyilmaz, Zafer; Ekim, Burcu; Kaya, Cem; Ergun, Mehmet Ali; Sonmez, Kaan; Güzel, SinemRing finger protein 43 (RNF43) encodes a transmembrane E3 ubiquitin ligase that negatively regulates canonical Wnt signaling and is classically associated with serrated polyposis syndrome and colorectal cancer. In this study, regarding a homozygous truncating RNF43 variant (NM_001305545.1:c.1906C>T; p.Gln636Ter) in a patient segregating with a severe neurodevelopmental phenotype characterized by developmental delay, neonatal hypotonia, recurrent seizures, progressive microcephaly, and bilateral optic atrophy, the loss of polarity defective 1 (plr-1), an ortholog of RNF43, was modeled in Caenorhabditis elegans and the phenotype was primarily characterized. The results demonstrated that loss of the plr-1 disrupted gamma aminobutyric acid (GABA)ergic axon organization, reduced locomotor speed calculated from 60 s recordings, and altered developmental growth. These findings expand the phenotypic spectrum of RNF43 and support a dosage-dependent developmental role.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 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.Editorial Editors’ Introduction: Spring 2026(Cambridge Univ Press, 2026) Kolluoğlu, Biray; Dinçer, Evren M.; Yükseker, DenizArticle Alexithymia, Rumination and Binge Drinking: The Mediating Role of Drinking Motives(Springer, 2026) Sokmez, Asli Bugay; Coskun, Muhammet; Alpay, Pelin; Kovács, Lilla Nóra; Kocsel, Natália; Kökönyei, GyöngyiThe objective of this study was to investigate whether the relationship between alexithymia and rumination, reflecting deficits in emotion processing and difficulties in emotion regulation, and binge drinking is mediated by drinking motives. A cross-sectional study was conducted with university students (N = 367, Mage = 22.38) who reported alcohol use in the past 30 days. Participants completed an online questionnaire comprising the Toronto Alexithymia Scale, the Alcohol Use Disorders Identification Test, the Drinking Motives Questionnaire, the Ruminative Response Scale, and the UPPS Impulsive Behaviour Scale. Binge drinking in the past 30 days was measured with a single item. The results of the mediation analyses indicated that the Difficulties in Identifying Feelings (DIF) component of alexithymia was directly related to risky drinking indexed by binge drinking in the past 30 days or the Alcohol Use Disorders Identification Test (AUDIT). The relationship between the DIF and the AUDIT was mediated by coping motives. Additionally, social motives mediated the relationship between reflection and binge drinking, while coping motives mediated the relationship between brooding and AUDIT, as well as between reflection and AUDIT. These findings confirm the importance of investigating emotion regulation as a proximal factor of risky drinking.