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Clairaut Conformal Submersions From Ricci Solitons, Murat Polat

Turkish Journal of Mathematics

In this study, we investigate Clairaut conformal submersions in the context of total manifolds that support a Ricci soliton structure. We begin by deriving the scalar curvature and Ricci tensor expressions associated with these manifolds, and we establish criteria under which the fibres can be characterized as almost Ricci solitons or Einstein manifolds. Additionally, we identify the conditions required for the base manifold to admit Ricci soliton and Einstein structures. We also determine the necessary conditions for a vector field ζ to be conformal or Killing. Moreover, we demonstrate that when the potential vector field of the Ricci soliton is …

A Delayed Siamr Prostate Cancer Model With Vertical Transmission And Treatment: Stability Analysis And Numerical Simulation, Hüseyi̇n Demir, İnci̇ Çi̇li̇ngi̇r Süngü, İbrahi̇m Keles

Turkish Journal of Mathematics

​In this paper, we propose and analyse a delayed-compartmental mathematical model of prostate cancer dynamics that incorporates vertical transmission and therapeutic intervention. The population is stratified into five compartments: susceptible (S), infected/virally activated (I), asymptomatic infectious under treatment (A), malignant untreated (M), and recovered (R). A discrete time delay τ > 0 is introduced in the force-of-infection term to model the age-dependent onset of susceptibility in middle-aged adult males. Vertical transmission of viral etiology at a rate qΛ ensures that a fraction of newborns enter the infected compartment directly, rendering the disease persistent regardless of the basic reproduction number R₀. We …

​Compact And Am-Compact Orthogonally Additive Operators, Bahri̇ Turan, Bi̇rol Altin

Turkish Journal of Mathematics

We show that compactness of orthogonally additive operators between Banach lattices is not preserved under taking the modulus by providing a nonlinear analogue of Krengel’s example. In contrast, for operators acting from a Banach lattice into an AM-space, AM-compactness is stable under lattice operations. Moreover, the space of absolutely norm bounded AM-compactorthogonally additive operators from a Banach lattice into an AM-space is a Banach lattice, and on such AM-spaces with the weak Fatou property, norm boundedness coincides with absolute norm boundedness.

Hyers-Ulam And Hyers-Ulam Rassias Stability Of Caputo Fractional Hahn Difference Equations, Karima Mohamed Oraby, Alaa E. Hamza, Afrah Al-Bossly

Turkish Journal of Mathematics

​In this paper, we investigate Hyers–Ulam and Hyers–Ulam–Rassias stability for fractional linear Hahn difference equations of Caputo Type. To the best of our knowledge, this is the first work concerning Hyers–Ulam type stability in the framework of Caputo fractional Hahn difference equations, thereby filling a significant gap in the literature on fractional stability theory. Our approach is based on establishing an equivalence between the fractional Hahn difference initial value problem and a corresponding fractional integral equation, via the Caputo–Hahn inversion formula. These results lay a strong groundwork for analyzing the stability of Hahn fractional systems, which could be useful in …

Stochastic Control Of Inventory And Scheduling Decisions In An Open Network Of Repairables, Erhun Özkan

Turkish Journal of Mathematics

We study maintenance operations for capital goods with repairable components. Because the downtime of a capital good is costly, the maintenance provider keeps an inventory of spare parts to quickly replace broken parts of the capital goods. After the replacement, the broken part is added to the repair facility’s repair queue. Upon a part breakdown, if there is no spare part in the inventory, then the maintenance provider has two options: (i) it can backorder the spare part demand, (ii) it can execute an emergency repair, which is done immediately and quickly, and is followed by a quick installation of …

A Full-Scale Watertight Workflow Numerical Study For A Triangular Fin And Tube Heat Exchanger, Hamdi̇ Selçuk Çeli̇k, Bahadir Doğan, Lati̇fe Berri̇n Erbay

Turkish Journal of Mathematics

In this study, the thermo-hydraulic characteristics of an air-cooled triangular finned tube heat exchanger were analyzed numerically. The full-scale heat exchanger was modeled using Ansys Fluent watertight workflow, considering water as the primer fluid to precisely investigate the effects of geometrical factors. The effects of fin height, fin width, and fin spacing of the triangular fins on the performance of the heat exchanger were examined using k-ω turbulence model. A basic finned-tube heat exchanger model, which was manufactured as a monolithic structure without tube-fin contact resistance by milling from aluminum 5083 material, was tested in an air tunnel to verify …

Aptamer–Gold Nanoparticle-Based Lab-In-A-Tube Colorimetric Detection Of Malathion: Evaluation With Classical And Digital Readout Techniques, Emi̇ne Güler Çeli̇k

Turkish Journal of Chemistry

Colorimetric biosensing devices represent an important class of point-of-care (POC) diagnostics due to their ability to provide visible test outputs, their ease of integration with smartphone-based sensing, and their portability for field testing. In the context of agrifood safety, there is a growing need for portable, robust, and cost-effective detection devices. Pesticide residues can be present in a wide range of environmental and food samples, from water resources to fruits and vegetables, resulting in an increasing global demand for on-site testing. Colorimetric assays, when combined with smartphone-based sensing, can effectively address these needs. In this work, the aggregation-induced color change …

Sensitive Electrochemical Sensor For Simultaneous Determination Of Epinephrine And Norepinephrine By Sio2np@Mwcnt-Cooh Nanoparticle-Modified Spces​, Merve Yilmaz Çilçar, Meli̇ke Bi̇lgi̇ Kamaç, Ayşenur Yilmaz Kabaca, Şahi̇n Toparli, Faruk Terzi̇oğlu, Emi̇r Ateş

Turkish Journal of Chemistry

Epinephrine (EP) and norepinephrine (NEP), both neurotransmitters, are two important biomolecules that play critical roles in the body, from the central nervous system to metabolic processes. They are also important biomarkers for clinical diagnosis and monitoring. In this study, a novel, fast, practical, and high-performance electrochemical sensor based on a SiO2NP@MWCNT-COOH nanocomposite was developed for the simultaneous determination of EP and NEP. The nanocomposite was modified onto the surface of screen-printed electrodes (SPCEs) and its characterization was performed (SEM-EDX, XRD, FTIR, CV, DPV, and EIS). The individual and simultaneous determinations of EP and NEP were performed using square-wave voltammetry, yielding …

Acetylcholinesterase Immobilization On A Natural Thin Membrane For Stable Biocatalyst Design, Si̇nem Öztürk, Ceyhun Işik, Mustafa Teke

Turkish Journal of Chemistry

This study involved the immobilization of acetylcholinesterase (AChE) onto a natural thin membrane extracted from the inner epidermal layer of Allium cepa, with the aim of enhancing the enzyme’s stability, activity, and reusability for potential biotechnological applications. The membrane, composed of biocompatible polymers and naturally occurring functional groups, was used as a sustainable support in a combined strategy involving adsorption followed by glutaraldehyde-mediated cross-linking. Immobilization conditions were optimized by evaluating key factors such as enzyme concentration, membrane quantity, cross-linker dosage, and contact time to achieve maximal catalytic efficiency. Structural and morphological changes on the membrane surface were assessed via scanning …

Folic Acid-Targeted Polymeric Complex Imprinted With Doxorubicin And Quercetin For Controlled Drug Delivery In Cancer Therapy, Ceren Türkcan, Emi̇rhan İşeri̇

Turkish Journal of Chemistry

​Cancer therapy is often limited by the systemic toxicity and dose-dependent adverse effects of conventional chemotherapeutic agents such as doxorubicin (DOX). In this study, a folic acid-functionalized molecularly imprinted polymeric complex based on poly(HEMA) crosslinked with ethylene glycol dimethacrylate was synthesized for the controlled release of DOX in combination with quercetin (QUE), a flavonoid known for its antioxidant and chemosensitizing properties. The aim of this work was to develop and physicochemically characterize a preliminary targeted drug delivery platform at a material-design level. The polymeric complex was synthesized via free-radical polymerization following a DOX–QUE precomplex formation step. Structural characterization was performed …

Antifungal Activity Of Isolated Compounds From Centaurea Salicifolia Var. Salicifolia Against Candida Species, Including Multidrug-Resistant C. Auris, C. Inconspicua, And C. Dubliniensis, Seli̇n Tufan, Di̇lek Şatana, Nur Tan

Turkish Journal of Chemistry

Natural compounds obtained from plants have always held great potential for drug discovery and, as such, have drawn the attention of researchers as novel antifungal molecules that can be effective against fungal resistance. The antifungal activity of sesquiterpene lactones has been extensively investigated against various fungal strains, but there is limited data on their antifungal activity against Candida species. Sesquiterpene lactones are abundant in the Asteraceae family, and 90% of identified sesquiterpene lactones have been isolated from members of this family. Three extracts obtained from the aerial parts of Centaurea salicifolia var. salicifolia, which had not been investigated prior to …

Electrochemical Determination Of Terbutaline Using A Sno2 Nanoparticle-Modified Carbon Paste Electrode, Rauf Gulamov, Şenol Alpat, Si̇bel Kilinç Alpat

Turkish Journal of Chemistry

Terbutaline hemisulfate (THS), a selective beta-2 agonist, is preferred as a bronchodilator for the treatment of asthma and bronchitis, as well as a tocolytic agent to delay labor in acute situations during premature birth. The use of beta-2 agonists above a certain dose is considered doping in sports competitions. Therefore, it is important that they be determined with high sensitivity and selectivity within a short analysis time. In this study, a SnO2 nanoparticle-modified carbon paste electrode was developed for the determination of THS. Cyclic voltammetry and differential pulse voltammetry were employed as electrochemical methods. The operating conditions of the developed …

Chitosan Microparticle-Based Antibacterial Nasal Barrier Formulation And In Vivo Evaluations, Güli̇z Ak, Ayça Erek, Tuğba Karakayali, Şadi̇ye Çeti̇n, Şenay Şanlier

Turkish Journal of Chemistry

Microorganisms remain a major cause of infectious diseases, emphasizing the need for alternative and complementary antimicrobial strategies. In this context, plant-derived materials have attracted increasing attention for their antimicrobial and protective properties. Chitosan, a biocompatible and cationic biopolymer, has emerged as an effective carrier system for encapsulating such plant-derived components. In this study, chitosan microparticles were prepared through ionic gelation followed by spray drying and loaded with thyme oil and olive leaf extract. The resulting microparticles exhibited an average size of approximately 1.8 μm and a total phenolic content of 23 mg GAE/g. These microparticles were incorporated into a glycerin–starch …

A Poly-L-Lysine-Functionalized Electrochemical Immunosensor Enables Highly Sensitive Detection Of Tumor Necrosis Factor Receptor-Associated Protein 1, Berfi̇n Vural, Mustafa Kemal Sezgi̇ntürk

Turkish Journal of Chemistry

Tumor necrosis factor receptor-associated protein 1 (TRAP-1), a member of the mitochondrial heat shock protein family (HSP90), is essential for protein homeostasis, stress response, and cell cycle. TRAP-1 not only optimizes cellular energy production but also prevents cell death, thereby supporting the survival and proliferation of tumor cells. In addition to cancer, TRAP-1 has been associated with Parkinson’s disease, certain autoimmune disorders, and abnormalities in the kidney and urinary tract. In this study, a unique and useful indium tin oxide-polyethylene terephthalate (ITO–PET)-based electrochemical biosensor is described for detecting the biomarker TRAP-1. The ITO–PET electrode, selected as the working electrode, is …

Cover And Contents

Turkish Journal of Chemistry

No abstract provided.

Profiling Arbutin As A Potent Cholinesterase And Gsk-3Β Inhibitor And Evaluating Its Cytotoxicity In Sh-Sy5y Cells For Alzheimer’S Disease Therapy, Shirin Tarbiat, Tuğba Bal, Deni̇z Gülmez

Turkish Journal of Biology

Background/aim: Alzheimer’s disease (AD) is a neurodegenerative disorder linked to cognitive decline and memory loss, marked by hyperphosphorylated tau tangles and decreased acetylcholine levels, which are affected by acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE) activity. Glycogen synthase kinase-3 beta (GSK-3β) also plays a role in AD through abnormal activation. In this study, the potential of β-arbutin to inhibit cholinesterases and GSK-3β was investigated, utilizing in vitro assays, cytotoxicity analysis, and molecular docking simulations to explore its therapeutic implications.

Materials and methods: Ellman’s technique was used to test the inhibitory effects of arbutin on cholinesterase enzymes. An ATP-Glo luminescent assay kit was …

Probiotic Intervention In Colorectal Cancer: The Cytotoxic And Apoptotic Potential Of Lactobacillus Cell-Free Supernatants, Bahar Yilmaz, Berna Erdal

Turkish Journal of Biology

Background/aim: Failures in the treatment of colorectal cancer (CRC) have increased scientific interest in the potential of the bioactive compounds contained in cell-free supernatants (CFSs) obtained from probiotic bacteria for cancer treatment. The aim in this study was to investigate the effects of CFSs obtained from Lactobacillus delbrueckii subsp. bulgaricus (L. bulgaricus) and Lactobacillus paracasei subsp. paracasei (L. paracasei) on colorectal cancer cell lines (HT-29 and Caco-2) and a healthy colon epithelial cell line (CCD841 CoN).

Materials and methods: Cytotoxic effects on the cell lines were determined by MTT assay. In line with the IC50 values obtained, morphological changes were …

Cover And Contents

Turkish Journal of Biology

No abstract provided.

Antiatopic Dermatitis Activity Of Lissachatina Fulica Mucin: Network Pharmacology Analysis And Experimental Validation, Atin Supiyani, Wasmen Manalu, Lina Noviyanti Sutardi, Mawar Subangkit, Andriyanto Andriyanto

Turkish Journal of Biology

Background/aim: Lissachatina fulica mucin (LFM) has been used as a nutraceutical, therapeutic agent, and cosmetic ingredient. The bioactivity of mucin depends on bioactive compounds whose composition is strongly influenced by the snail’s diet. This study investigated the bioactive compounds in L. fulica mucin as potential therapeutic agents for atopic dermatitis (AD).

Materials and methods: LFM was collected from snails fed long beans and melon rinds for 4 weeks, freeze-dried, and analyzed using liquid chromatography–mass spectrometry followed by network pharmacology (NP) analysis to identify its bioactive compounds. A total of 60 BALB/c mice were sensitized on the dorsal skin with 1% …

The N-Terminal, Wd40, And C-Terminal Domains Of Wdr-31 Control Ciliary Localization And Cooperate With Elmod/Rp2 Gaps To Maintain Membrane Compartmentalization, Sebi̇ha Çevi̇k, Fatma Güzel

Turkish Journal of Biology

Background/aim: WD40 repeats are found in many ciliary proteins. Although the WD40 repeat-containing WD repeat-containing protein 31 (WDR-31) is known to regulate ciliary protein trafficking and morphology, the specific contributions of its N-terminal, WD40, and C-terminal domains to protein localization and ciliary gate integrity remain unclear. Aim of this study is to dissect the functional roles of WDR-31 domains by investigating their contributions to ciliary localization, ciliary protein trafficking, and gate integrity.

Materials and methods: Using CRISPR/Cas9 technology, we generated Caenorhabditis elegans strains with in-frame deletions that removed the N-terminus (WDR-31(ΔN)), WD40 (WDR-31(ΔWD)), and C-terminus (WDR-31(ΔC)). We next examined the …

Discovery And Functional Characterization Of Novel Programmed Death-Ligand 1 Monoclonal Antibodies, Nurşah Ersezen, Mai̇de Şeker, Arzu Aysan, Durmuş Akdoğan, Mehmet Ender Avci, Asli Kurden Pekmezci̇, Si̇bel Kalyoncu Uzunlar, Mehmet İnan, Tamer Yağci

Turkish Journal of Biology

Background/aim: Targeted therapies with monoclonal antibodies provide cancer patients with better prognosis and diseasefree survival. The blockade of immune checkpoints, including programmed cell death protein-1 (PD-1) and its ligand PD-L1, with monoclonal antibodies may boost immune responses against tumors and is regarded as an effective strategy in cancer immunotherapy. We describe the generation of anti-PD-L1 monoclonal antibodies with high affinity and specificity, and we assess their potential for therapeutic use in cancer.

Materials and methods: Hybridomas were selected for PD-L1 specificity and cross-reactivity with other immune checkpoint proteins and PD-L1 orthologs using indirect ELISA. Immunofluorescence and Western blotting assays were …

Cover And Contents

Turkish Journal of Medical Sciences

No abstract provided.

Face Mask Littering: Environmental Impacts, Regulatory Challenges, And Ai-Driven Waste Management Strategies For The Post-Pandemic Era, Pri̇yanka Rathee, Sari̇ta Khatkar, Renu Sehrawat, Pooja Rathee, Anurag Khatkar, Esra Küpeli̇

Turkish Journal of Medical Sciences

The widespread use of polypropylene-based face masks during the COVID-19 pandemic created a significant and persistent source of plastic pollution. This review aims to provide an integrative assessment of the environmental, toxicological, and public health implications of face mask litter and evaluate current waste management challenges and emerging technological solutions in the postpandemic context. A narrative review approach was employed, synthesizing literature published between 2020 and 2025 and indexed in major scientific databases including Web of Science, Scopus, and PubMed. Studies were selected based on their relevance to the issues of environmental contamination, microplastic generation, toxicological effects, regulatory frameworks, and …

Male Osteoporosis: Pathophysiology, Risk Assessment, And Evidence-Based Management, Seli̇n Teki̇n, Alper Gürlek

Turkish Journal of Medical Sciences

Osteoporosis in men is a common yet underrecognized condition associated with substantial fracture-related morbidity and excess mortality. Although men generally attain higher peak bone mass than women, age-related changes in bone microarchitecture, progressive cortical bone loss, declining sex steroid bioavailability, and a high prevalence of secondary causes contribute to a significant lifetime fracture risk. Importantly, a large proportion of fragility fractures in men occur at bone mineral density (BMD) values above the osteoporotic threshold, highlighting the limitations of BMD-based diagnosis alone. This review provides a comprehensive overview of the epidemiology, pathophysiology, and clinical characteristics of osteoporosis in men, with particular …

Direct Pars Repair Techniques For Lumbar Spondylolysis: A Comparative Literature Review ​, Kami̇l C. Kose, Moustafa Ibrahim, Ni̇cholas D. Haden, John Afolayan, Hanny Anwar

Turkish Journal of Medical Sciences

Background/aim: Lumbar spondylolysis, a pars interarticularis defect affecting approximately 3%–6% of the general population, presents a significant clinical challenge in young adults and athletes. When conservative management fails, direct pars repair offers an attractive alternative to spinal fusion by preserving segmental motion and reducing the risk of adjacent segment degeneration. This narrative review compares seven principal direct pars repair techniques—Buck’s technique, Scott’s wiring method, Morscher’s hook-screw system, pedicle screw-based constructs, the V-rod/U-rod (Gillet technique), the smiley face rod construct, and the dualstability construct (DSC)—evaluating their biomechanical properties, clinical outcomes, fusion rates, and complication profiles.

Materials and methods: A narrative literature …

Hearing Loss In Behçet’S Syndrome: Prevalence And Associated Factors In A Nationwide Cross-Sectional Analysis ​, Alper Doğanci, Serdar Can Güven, Nuray Yilmaz Çakmak, Nurhan Güven, Sali̇h Başer, Nesli̇han Öztürk, Şuayi̇p Bi̇ri̇nci̇, Nai̇m Ata

Turkish Journal of Medical Sciences

Background/aim: The aim of this study was to investigate the prevalence of hearing loss in Behçet’s syndrome and its associations with other disease manifestations, comorbidities, and treatment agents. To the best of our knowledge, this is the most comprehensive study to date addressing this issue.

Materials and methods: The study was designed as a cross-sectional, nationwide study. The Turkish Ministry of Health National Electronic Database (e-Nabız) was used under the supervision of the Ministry of Health to extract patient data. A nationwide cohort was established from patients who had been assigned an ICD-10 code for BS (M35.2) on at least …

A Comparative Analysis Of Clinical Quality And Readability Of Neuropathic Pain Patient Information Leaflets: Türkiye Versus The United States, Gonul Sari, Argun Pire

Turkish Journal of Medical Sciences

Background/aim: Neuropathic pain management requires high patient adherence and complex dose-titration regimens, making the readability of patient information leaflets (PILs) a critical patient safety factor. This study aimed to compare the clinical content quality and linguistic readability of PILs for neuropathic pain medications between Türkiye (TİTCK) and the United States (DailyMed).

Materials and methods: A total of 11 pairs of innovator medications were analyzed. Clinical content was assessed using the 15-item Keystone Clinical Content Checklist (KCCC). Readability was assessed using the Ateşman index for Turkish texts and the Flesch Reading Ease Score (FRES) for English texts. Information quality and reliability …

Demographic And Clinical Characteristics Of Frequent Users Of Emergency Medical Services In Türkiye ​, Burak Bekgöz, İshak Şan

Turkish Journal of Medical Sciences

Background/aim: Overuse of emergency medical services (EMS), particularly unnecessary ambulance requests, places considerable strain on limited healthcare resources and can delay responses to urgent cases. The present study analyzes the demographic characteristics, diagnoses, urgency, and hospital transfer status of frequent users of EMS in Türkiye.

Materials and methods: Included in the study were 41,113 patients who requested EMS four or more times within a year (defined as frequent users for the purpose of the study), excluding interhospital transfers. Data were accessed from the Emergency Medical Services Automation System (ASOS) database, which contains details of patient demographics, diagnoses, triage codes, reasons …

Comparing Age Of Obesity Onset, Concerns About Weight And Body Shape, And Quality Of Life In Individuals Seeking Bariatric Surgery ​, Vi̇ldan Çakir Kardeş, Özge Saraçli, Nuray Atasoy, Levent Ati̇k, Si̇bel Kahraman Gi̇rgeç

Turkish Journal of Medical Sciences

Background/aim: This study explored the relationship between concerns about weight and body shape and quality of life in bariatric surgery candidates with morbid obesity regarding the onset of the weight problem in childhood, adolescence, or adulthood.

Materials and methods: We included 453 patients who applied to our center for preoperative bariatric surgery assessment between January 2010 and April 2019. We reviewed the sociodemographic information, psychiatric diagnoses, and results of the Body Shape Questionnaire-34, Quality of Life Scale, Beck Depression Inventory, and Beck Anxiety Inventory of all patients.

Results: Concerns about weight and body shape were increased in women (p < 0.001), unemployed patients (p = 0.001), those with a comorbid psychiatric disorder (p < 0.001), and those with childhood- or adolescent-onset of weight problems (r = –0.170; p < 0.001). Concerns about weight and body shape had a relationship with the vitality (r = –0.434), mental health (r = –0.464), social functioning (r = –0.418), pain (r = –0.307), and general health (r = –0.352) subscale scores of quality of life. Physical functioning was higher (p = 0.037) in patients with childhood- or adolescent-onset obesity compared to patients with adult-onset obesity, while mental health was higher (p = 0.001) in the latter group. Individuals with childhood- or adolescent-onset obesity inquired about bariatric surgery options at an earlier age (p < 0.001).

Conclusion: …

Changes In T-Cell Subsets And Their Relationships With Disease Severity In Patients With Alopecia Areata, Hati̇ce Türk Daği, Hülya Özdemi̇r, Mehmet Akyürek, Fatma Tunçez Akyürek, Hasi̇be Artaç

Turkish Journal of Medical Sciences

Background/aim: Alopecia areata (AA) is a nonscarring hair loss disorder characterized by genetic susceptibility, environmental triggers, and T-cell–mediated autoimmunity. While various CD4+ and CD8+ T-cell subsets are implicated in its pathogenesis, the roles of follicular T-cell (Tfh), peripheral T-cell (Tph), and regulatory T-cell (Treg) subsets– particularly within the CD8+ population–remain incompletely defined. This study aimed to characterize circulating CD4+ and CD8+ T-cell subsets in Turkish patients with AA and to evaluate their associations with disease activity, duration, and severity.

Materials and methods: A total of 40 patients with AA and 40 healthy controls were enrolled. CD4+ and CD8+ T-cell subsets—including …