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Characterization Of Poly-Β-Hydroxybutyrate And Its Biosynthesis In Priestia Endophytica Ucm B-5715, Alina Kharchuk, Maksym Kharchuk, Maksym Kharkhota, Sergiy Rogalsky, Oksana Tarasyuk, Oleksandr Kisten, Anastasiia Hubina, Illya Kapats, Liliia Avdieieva

Turkish Journal of Biology

Background/aim: Polyhydroxyalkanoates (PHAs) are biodegradable biopolymers with promising applications in biotechnology and medicine; however, the diversity of their biosynthesis within the genus Priestia remains poorly characterized. Although Priestia species have been recognized as potential PHA producers, the detailed genomic architecture and physicochemical properties of the polymers synthesized by these bacteria, particularly in the type strain, remain poorly understood. This study aimed to characterize the poly-β-hydroxybutyrate (PHB) produced by Priestia endophytica UCM B-5715 and to investigate the PHB biosynthetic genes across related strains.

Materials and methods: PHB granules were visualized and measured using fluorescence microscopy, transmission electron microscopy, and scanning electron …

Nutrient Uptake Of Two Microalgae From Culture Medium Under Nickel Treatment, Di̇lara Erdaği, Büşranur Şeker, Celal Caner, Gi̇zem Çeti̇n, Hüseyi̇n Altundağ, Hati̇ce Tunca

Turkish Journal of Biology

Background/aim: Phycoremediation is essential for purifying wastewater of heavy metals to ensure a sustainable environment, as these components can be detrimental to organisms upon entering the food chain. Among heavy metals, nickel is vital at low concentrations due to its presence in the active sites of many metalloenzymes in algae. However, at high concentrations, it disrupts the functioning of many metabolic reactions. This study examines the effects of nickel treatment on the uptake of macro- and micronutrients in medium by algae via ion exchange pathways or in competition with other metals. The study aims to determine the effects of nickel …

Hla Allele And Haplotype Diversity In Central Anatolia: A Comparative Analysis Of Donors And Transplant Candidates Across Six Hla Loci (Hla-A, Hla-B, Hla-C, Hla-Drb1, Hla-Dqb1, And Hla-Dpb1), Emel Yantir, Eren Gündüz, Ertuğrul Çolak

Turkish Journal of Medical Sciences

Background/aim: Human leukocyte antigen (HLA) polymorphisms play a central role in immune recognition, disease susceptibility, and transplant success. The distribution of HLA alleles and haplotypes varies among ethnic and geographic populations. Despite several regional studies conducted in Türkiye, large-scale and comprehensive investigations comparing HLA profiles between healthy individuals and transplant candidates remain limited. The aim of this study was to compare the distribution of HLA profiles among donors, hematopoietic stem cell transplantation (HSCT) candidates, and solid organ transplant candidates.

Materials and methods: A total of 8472 individuals were included in the study, comprising 6422 donors and 2050 transplant candidates. HLA …

Impact Of Race-Based And Race-Free Ckd-Epi Equations On Estimated Glomerular Filtration Rate In A Multicenter Retrospective Cohort Of Autosomal Dominant Polycystic Kidney Disease, Özgür Akin Oto, Abdulmeci̇t Yildiz, İsmai̇l Koçyi̇ği̇t, Hali̇l Yazici, Sai̇de Eli̇f Güllülü Boz, Yi̇ği̇t Kurtuluş, Alparslan Demi̇ray, Müge Doksan, Vafa Suleymanova, Ece Ük, Alper Akin, Bahar Bastani, John C. Edwards, Krista Leigh Lentine, Yaşar Kerem Çalişkan

Turkish Journal of Medical Sciences

Background/aim: The 2021 revision of the Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) equation, which eliminates race-based coefficients, may significantly influence disease staging and treatment in autosomal dominant polycystic kidney disease (ADPKD). This study was designed to evaluate the impact of the 2021 race-free CKD-EPI equation on estimated glomerular filtration rate (eGFR) and chronic kidney disease (CKD) staging in a multi-ethnic ADPKD population.

Materials and methods: In this multicenter, retrospective cohort study, 597 ADPKD patients were evaluated, including 515 self-identified as Caucasian and 82 as African-American. eGFR values at baseline and final follow-up were calculated using both the 2009 and 2021 …

Association Of Vitamin D, Oxidative Stress Markers, And Hormonal Factors With Male Infertility: A Case-Control Study In Pakistan, Muhammad Tayyab Ihsan, Ayesha Ali Malick, Sher Khan, Sher Khan, Muhammad Tahir Khan, Haq Nawaz Khan, Rehana Rehman

Turkish Journal of Medical Sciences

Background/aim: Infertility impacts around 15% of couples worldwide, with male factors accounting for approximately 50% of cases. Despite this significant share, male infertility remains understudied, particularly in developing nations such as Pakistan. The present study explores the association between male infertility and seminal plasma concentrations of oxidative stress markers, inhibin B, and vitamin D, along with their relationship with sperm parameters.

Materials and methods: The dataset of the study consisted of seminal plasma levels from 30 fertile and 60 infertile males. Total antioxidant capacity (TAC), Vitamin D, malondialdehyde (MDA), 4-hydroxynonenal (4-HNE), lipid peroxide (LPO), superoxide dismutase (SOD), and inhibin B …

Preliminary Population Genetic Analysis Of 12 X-Str Loci In A Sample From Türkiye: Allele Frequencies, Haplotype Diversity, And Linkage Disequilibrium​, Hizir Asliyüksek, Esra Güzel Tanoğlu, Abdulkadi̇r Can, Muhammed Fevzi̇ Esen, Yusuf Atan

Turkish Journal of Medical Sciences

Background/aim: X-chromosomal short tandem repeats (X-STRs) are informative genetic markers in kinship testing and specific forensic contexts, particularly when standard autosomal approaches are less informative. This study aimed to provide preliminary allele frequency, haplotype diversity, and linkage disequilibrium (LD) data for 12 X-STR loci in a sample from Türkiye.

Materials and methods: A total of 136 unrelated individuals from Türkiye were genotyped for 12 X-STR loci. Inferential analyses of X-linked loci require diploid genotypes; therefore, allele frequencies, Hardy–Weinberg equilibrium (HWE), LD, and regional comparisons were based primarily on female samples (n = 115), whereas male haplotypes (n = 21) were …

In Silico Evaluation Of The Role Of Pea3 Subfamily Ets Transcription Factors In Chemoresistance In Ovarian Cancer, Fevzi̇ Coşkun Sökmen, Lai̇ka Kardana, Hi̇kmet Yilmaz, Ahmet Çağlar Özketen, Aynur Karadağ Gürel, Özge Atay, Hasan Hüseyi̇n Kazan

Turkish Journal of Medical Sciences

Background/aim: The E26 transformation-specific family of transcription factors regulates the cell cycle and apoptosis that are crucial for carcinogenesis. More specifically, the PEA3 subfamily—comprising ETS variant (ETV) transcription factors ETV1, ETV4, and ETV5—has been implicated in multiple oncogenic signaling pathways and chemotherapy resistance. While cisplatin is still a widely used chemotherapeutic treatment for ovarian cancer, its therapeutic efficacy is sometimes limited by the induction of resistance mechanisms. The present study investigates the potential role of PEA3 subfamily genes in cisplatin resistance in ovarian cancer through comprehensive in silico analyses.

Materials and methods: Cisplatin response data for ovarian cancer were obtained …

Omega-3–Rich Fish Oil Lipid Emulsions Significantly Prevent Sepsis-Driven Mesenteric Hypoperfusion And Multi-Organ Injury In Murine Models, Gökşen Öz, Esi̇n Özçelebi̇, Ayşe Yeşi̇m Göçmen, Cenk Sükmensüer, Selma Yildirim, Arzu Topeli̇, Alper Bektaş İski̇t

Turkish Journal of Medical Sciences

Background/aim: Parenteral feeding is used in critically ill patients when enteral nutrition is inadequate or intolerable, and the gastrointestinal tract is not functioning properly. Lipid emulsions play a major role in parenteral nutrition because they supply necessary fatty acids and a high-calorie density. We investigated the effects of parenteral lipid emulsions on mesenteric perfusion, inflammation-induced oxidation, and organ damage in lipopolysaccharide-induced mice endotoxemia model.

Materials and methods: In septic mice, organ damage induced by lipopolysaccharide was assessed by histopathology and biochemical examination. Additionally, an ultrasonic blood flowmeter was used to measure the impact of lipid emulsions on mesenteric blood flow. …

Analytical Eigenmode Framework For Triplet-Mediated Fluorescence Dynamics Under Pulsed Excitation, Bariş Demi̇rbay

Turkish Journal of Physics

An exact analytical solution to a three-state photophysical model is presented to explicitly map the time-resolved fluorescence dynamics of a fluorophore under pulsed excitation. As distinct from earlier analytical treatments that primarily focused on transient absorption and total ground-state depletion, the proposed eigenvalue-eigenvector framework captures both transient and steady-state emission responses. The photophysical model accounts for electronic transitions between the singlet ground state, the excited singlet state and a long-lived triplet state, enabling a treatment of excitation, radiative decay, intersystem crossing, together with triplet-state relaxation. By diagonalizing the rate matrix consisting of phenomenological transition rates, closed-form expressions for the time-dependent …

Comprehensive Geriatric Assessment Identifies Multidimensional Vulnerabilities In Older Adults With Heart Failure, Ci̇han Kiliç, Rengi̇n Demi̇r, Özlem Yilmaz Aykent, Zerri̇n Yi̇ği̇t, Pinar Küçükdağli, Banu Özulu Türkmen, Güli̇stan Bahat, Mehmet Aki̇f Karan

Turkish Journal of Medical Sciences

Background/aim: Heart failure (HF) in older adults is frequently accompanied by geriatric syndromes that remain unrecognized in conventional cardiac evaluations. The vulnerabilities of older adults with and without HF in terms of muscle strength, physical performance, functional capacity, frailty, nutritional status, cognition, mood, anxiety, polypharmacy, and comorbidity were investigated using comprehensive geriatric assessment (CGA).

Materials and methods: A cross-sectional study was conducted in two academic outpatient clinics, enrolling 420 adults aged ≥60 years, including 92 (21.9%) with HF. Data included sociodemographic characteristics, anthropometric measurements, and CGA parameters: handgrip strength, the Five-Times Sit-to-Stand Test (FTSST), the Short Physical Performance Battery (SPPB), …

Clinical, Hormonal, And Treatment Outcomes In 247 Patients With Acromegaly: A Single Tertiary Center Experience, Ümran Gül, Beki̇r Uçan, Hayri̇ Bostan, Hakan Düğer, Hayri̇ Kertmen, Caner Ünlüer, Hali̇l Durantaş, Oğulcan Boz, Ceren Karaçalik Ünver, Burak Menekşe, Sema Hepşen, İlknur Öztürk Ünsal, Mustafa Özbek, Erman Çakal, Muhammed Kizilgül

Turkish Journal of Medical Sciences

Background/aim: This study aimed to evaluate the demographic, clinical, and hormonal characteristics; comorbidities; surgical pathology; treatment modalities; and long-term clinical outcomes of patients diagnosed with and managed for acromegaly at our tertiary referral center over a 15-year period.

Materials and methods: Between 2010 and 2024, 247 patients with acromegaly were evaluated. Diagnosis and biochemical remission were determined according to the 2024 Acromegaly Consensus Criteria.

Results: The median follow-up duration was 8 years (IQR: 3–14). At the time of diagnosis, the most frequent pituitary hormone deficiency was secondary adrenal insufficiency, present in 17.8% of patients. The most common comorbidities were hypertension …

Bridging The Methodological Gap In Multitrauma Literature: A Competency-Based Educational Framework And Clinical Appraisal Filter, Şaki̇r Hakan Aksu, Burcu Doğan, Merve Yazla

Turkish Journal of Medical Sciences

Background/aim: The statistical complexity of contemporary multitrauma literature has increased considerably in recent years, which may pose challenges for clinicians seeking to interpret high-impact research and apply evidence-based practices. Characterizing this methodological landscape and exploring education-oriented approaches may help to improve the interpretability of the literature and support informed clinical decision-making.

Materials and methods: A cross-sectional analysis was conducted on the 100 most-cited multitrauma studies published in Science Citation Index Expanded journals indexed in the Web of Science database between January 2018 and November 2025. The statistical methods used in each article were categorized into the three competency levels of …

Postoperative Normocalcemic Hyperparathyroidism: A Comprehensive Analysis Of 510 Cases, Alparslan Ertenli̇ce, İbrahi̇m Kilinç, Mustafa Oruç

Turkish Journal of Medical Sciences

Background/aim: Postoperative normocalcemic hyperparathyroidism (NC-HPT) is defined as elevated parathyroid hormone (PTH) levels despite normal calcium levels after parathyroidectomy for primary hyperparathyroidism (PHPT). This study investigates the demographic, biochemical, and histopathological factors associated with NC-HPT in a large patient cohort and presents the follow-up outcomes.

Materials and methods: The initial study sample included 571 patients who underwent surgery for PHPT between January 2018 and January 2024, 510 of whom were analyzed retrospectively after the application of the exclusion criteria. Preoperative and postoperative biochemical parameters, bone mineral density, pathological findings, and follow-up data were evaluated. NC-HPT was defined as postoperative PTH …

Alterations In Gut Microbiota Composition In Adult Patients With Familial Mediterranean Fever: A Pilot Case–Control Study, Nazi̇fe Şule Yaşar Bi̇lge, Vicente Pérez Brocal, Ti̇muçi̇n Kaşi̇foğlu, Uğur Bi̇lge, Ni̇lgün Kaşi̇foğlu, Andres Moya, Ener Çağri Di̇nleyi̇ci̇

Turkish Journal of Medical Sciences

Background/aim: Although familial Mediterranean fever (FMF) is a monogenic disease, recent evidence suggests that the gut microbiota may play a role in its pathogenesis or phenotypic expression. We conducted a pilot exploratory study to evaluate the intestinal microbiota composition in patients with FMF and compare it to that of healthy controls.

Materials and methods: In this prospective cohort study, 10 adult patients with FMF receiving colchicine and 10 age- and sex-matched healthy controls were enrolled. Fecal samples were collected and stored at –80 °C until DNA extraction. The V3–V4 region of the 16S rRNA gene was amplified and sequencing was …

Vnotes High Uterosacral Ligament Suspension Versus Laparoscopic Lateral Suspension In The Management Of Vaginal Vault Prolapse: Initial Experience In A Single Tertiary Center, Ramazan Adan, Fati̇h Şahi̇n, Ulya Üskent, Mehmet Gökhan Çulha, Arzu Bi̇lge Teki̇n

Turkish Journal of Medical Sciences

Background/aim: The optimal technique for vaginal vault prolapse correction has yet to be identified. This study aimed to evaluate the anatomic and functional outcomes of women who underwent vaginal natural orifice transluminal endoscopic high uterosacral ligament suspension (vNOTES HUSLS) or laparoscopic lateral suspension (LLS).

Materials and methods: This retrospective study included symptomatic women with stage ≥2 vault prolapse who underwent vNOTES HUSLS or LLS between January 2019 and June 2022 at a tertiary center. The surgical efficacy, postoperative outcomes, complication rates, and recurrence frequencies of these procedures were compared. The primary outcomes of the study included anatomical success, patient-reported (subjective) …

Comparative Efficacy Of Controlled Internal Drug Release And Medroxyprogesterone Acetate Sponges On Ovulatory Follicle Growth In The Ovsynch Protocol During The Breeding Season In Cyclic Nili Ravi Buffaloes, Muhammad Binyameen, Ali Husnain, Saba Anwar, Muhammad Waseem, Muhammad Saleem

Turkish Journal of Veterinary & Animal Sciences

The objective of the experiment was to compare the dominant follicle size, growth rate of the dominant follicle, estrus response, plasma progesterone concentration, and pregnancy in Nili Ravi buffaloes synchronized by controlled internal drug release (CIDR; 1.38 g) and medroxyprogesterone acetate sponge (MPAS; 250 mg) in the ovulation synchronization (OvSynch) protocol. The experiment had a randomized complete block design. Buffaloes (n = 42) were blocked by parity, body weight, body condition score, and ovarian status, and, within the block, they were randomized to receive either CIDR or MPAS and that day was considered day 0 of the experiment. On days …

Origins Of Mitochondrial Diversity In Turkish Sheep Breeds: Anatolia As A Contact Zone Or Refugial Center?, Nezi̇h Ata, İbrahi̇m Cemal

Turkish Journal of Veterinary & Animal Sciences

Advances in molecular genetics, especially the integration of mitochondrial DNA (mtDNA) analyses, have significantly transformed our understanding of the origins, geographical centers, and dispersal dynamics of domestication, a field traditionally based on archaeological and morphological evidence. In this study, the mtDNA control-region sequences of 296 individuals from 15 native Turkish sheep breeds were analyzed to clarify their maternal genetic diversity and evolutionary origins. Sequencing of a 531-bp D-loop fragment revealed 53 polymorphic sites and 78 distinct haplotypes, indicating substantial haplotypic diversity (Hd = 0.918) and nucleotide diversity (π = 0.01391) within these populations. All five major ovine mitochondrial haplogroups (A, …

The In Vitro Feeding Of Hyalomma Marginatum (Koch, 1844), Nesli̇han Ölmez, Bariş Sari, Zati̇ Vatansever

Turkish Journal of Veterinary & Animal Sciences

Ticks are obligate hematophagous ectoparasites that play a major role in the transmission of pathogens affecting both animals and humans. Investigations into tick biology, pathogen transmission, and the development of effective control strategies have traditionally depended on the extensive use of laboratory animals. Consequently, the development of reliable in vitro feeding systems is a valuable alternative approach with the potential to reduce animal use in tick research. In the present study, a previously described silicone membrane artificial feeding system was modified and applied for the in vitro feeding of Hyalomma marginatum (Koch, 1844). Feeding units were prepared using bovine blood …

Immunohistochemical Expression Of Lgr5 In The Bovine Ovary, Oviduct, And Uterus, Aytül Kürüm, Yasi̇n Özkabadayi, Hakan Kocamiş, Mustafa Türk, Si̇yami̇ Karahan

Turkish Journal of Veterinary & Animal Sciences

Leucine-rich repeat-containing G-protein coupled receptor 5 (LGR5) has recently been considered as a stem cell marker seen especially in mitotically active tissues. The aim of the present study was to investigate the immunohistochemical expression of LGR5 in the bovine reproductive tract, which is regularly renewed in response to hormonal changes throughout the estrous cycle. The oviduct (ampulla, isthmus, and fimbria), uterus, and ovary tissue samples were collected from 12 cows at a local slaughterhouse. The samples were further identified as follicular (n = 6) or luteal (n = 6), subjected to routine histological procedures, and processed for immunohistochemical expression of …

Comparison Of Bacteriological Culture And A Multiplex Real-Time Pcr Kit For The Detection Of Mastitis Pathogens In Small Ruminants, Ebru Karakaya Bi̇len, Serpi̇l Kahya Demi̇rbi̇lek, Bariş Güner, Öznur Yilmaz Koç, Ali̇ Ünver, Merve Yildiz, İrem Çakmak, Abdulkadi̇r Keski̇n

Turkish Journal of Veterinary & Animal Sciences

This study aimed to evaluate the applicability of a multiplex real-time PCR (rPCR) kit, originally developed for bovine mastitis, for detecting mastitis pathogens in small ruminants and reducing bacterial identification time compared with conventional bacteriological culture (BC). Milk samples were obtained from 175 sheep and 124 goats and included cases of clinical mastitis (n = 57) and subclinical mastitis (n = 242). With BC, bacterial growth was detected in 125 of 299 milk samples (41.8%), yielding a total of 169 bacterial isolates. The pathogens most frequently isolated by BC were coagulase-negative staphylococci (58.0%), followed by Streptococcus spp. (9.4%), Staphylococcus aureus …

Patterns And Drivers Of Cladocera Community Structure In The Black Sea, Elena Bisinicu, Luminita Lazar

Turkish Journal of Zoology

Cladoceran community dynamics were examined in the Romanian sector of the Black Sea during the warm seasons of 2013– 2020, using Marine Reporting  Units (MRUs) to evaluate spatial heterogeneity across transitional, coastal, and  marine waters. Analyses of density, biomass, mean individual biomass (MIB), and  species composition revealed interannual fluctuations superimposed on strong  nearshore–offshore gradients, with higher values in transitional and coastal MRUs.  The assemblage was consistently dominated by Pleopis polyphemoides and Penilia  avirostris, which together accounted for most of the total abundance and biomass.  Multivariate analysis identified significant differences in taxonomic composition  across MRUs and years, while correlation analyses highlighted …

Cover And Contents

Turkish Journal of Zoology

No abstract provided.

Endemism Patterns Of Leaf Beetles (Coleoptera: Chrysomelidae) In Türkiye, İsmai̇l Şen, Ali̇ Gök

Turkish Journal of Zoology

In this study, the distribution of endemic leaf beetles in Türkiye was analyzed  holistically at the provincial scale using species richness (ENR), corrected weighted  endemism (CWE), and range-restricted endemism (RRE) indices. A total of 95  endemic taxa were found in Türkiye and these taxa exhibited significant spatial  heterogeneity in terms of richness and extent of distribution. The Western and  Central Taurus Mountains and the Eastern Black Sea Region were found to be the  main centers of endemism, with high densities of narrowly distributed and  geographically restricted species. These patterns clearly demonstrate that key  biogeographic factors, such as steep elevation gradients, …

The Effect Of Spatial Scale Of Habitat On Abundance Of Roe Deer (Capreolus Pygargus) And Water Deer (Hydropotes Inermis Argyropus) During Summer In South Korea, Naeyoung Kim, Hyejin Kim, Hyoun-Gi Cha, Hyun-Su Hwang

Turkish Journal of Zoology

Understanding species-specific habitat preferences provides essential ecological  information about interactions among habitat components. In South Korea, roe deer  (Capreolus pygargus) and water deer (Hydropotes inermis argyropus) are the  dominant large herbivorous mammals of the family Cervidae. The increasing populations of these species have led to ecological and economic  challenges. Therefore, we investigated the effects of spatial scale characteristics on  the habitat preferences of roe deer and water deer. From June to August each year  between 2021 and 2023, we calculated the relative abundance index (RAI) using  camera-trap data and analyzed patch characteristics in the study area using remote  sensing techniques, …

The Ecotoxicological Impact Of Polystyrene On Lissachatina Fulica: A Study Of Growth,  Pedal Mucus Histological Changes, And Protein Mucus Analysis, Atin Supiyani, Wasmen Manalu, Lina Noviyanti Sutardi, Mawar Subangkit, Andriyanto Andriyanto

Turkish Journal of Zoology

Lissachatina fulica mucin can be used as a nutraceutical agent depending on the  quality of their feed. Polystyrene (PS) waste harms soil and plants consumed by  snails, potentially affecting the quality of mucin production. This study investigated  the impact of PS on growth and mucus-producing cell characteristics as well as the  network pharmacology of mucin protein components. Fifty 5–6 cm L. fulica snails  (20–24 g) were fed organic waste (OW) and organic waste with PS (OWPS). After 28  days of ad libitum access to food, the snails’ mucus, meat, and shells were  collected and weighed. Tissue samples from the anterior …

Accurate Diagnosis Of Diseases By A Novel Ai Pipeline Based On Feature Extraction, Feature Ranking, And Feature Selection From Medical Images, Tuğba Nur Bozkurt, Mehmet Emi̇n Yüksel

Turkish Journal of Electrical Engineering and Computer Sciences

The rapid growth of the global population has led to a substantial increase in the number of patients, while the availability of healthcare professionals has not expanded at a comparable rate. This imbalance highlights the urgent need for efficient and reliable computer-aided decision support systems that can reduce clinical workload while maintaining high diagnostic accuracy. In this study, a novel and systematically integrated artificial intelligence-based pipeline is proposed for medical image classification, combining statistical significance-driven feature ranking with evolutionary feature selection in a unified framework. The proposed pipeline consists of four sequential stages: feature extraction, ranking, selection, and classification. Features …

A Descriptive Analysis Of Plant Leaf Disease Detection Using Machine Learning And Deep Learning Models: A Systematic Review, Arzoo Chamoli, Anuj Kumar

Turkish Journal of Electrical Engineering and Computer Sciences

Plant leaf disease detection (PLDD) is a growing active research area with burgeoning practical applications across various sectors such as agricultural monitoring, food security, and environmental conservation. Accurate segmentation and classification of plant leaf diseases remains a key challenge in the field of plant leaf disease prediction. The challenge demands automated methods for the plant disease identification because it needs to develop better crop management systems, which will boost agricultural production. In this article, we provide a systematic review of various machine learning (ML) and deep learning (DL) methods extensively used for PLDD. The review strategy follows a formal protocol, …

Complex-Valued Convolutional Neural Network With Time-Frequency Representation For Electrocardiogram-Based Arrhythmia Detection, Kajeeth Kumar Gurusamy, Muthurajkumar Sannasy

Turkish Journal of Electrical Engineering and Computer Sciences

This research proposes an end-to-end procedure for arrhythmia detection based on electrocardiogram (ECG) signals using complex-valued convolutional neural network (CVCNN) incorporated with time-frequency representation. The proposed model leverages complex numbers to capture amplitude and phase information that enhances the ability of the model for detecting time-frequency variation in cardiac signals. First, signal preprocessing techniques---including normalization, wavelet denoising, and R-peak detection---are applied. Subsequently, the model extracts complex features from raw ECG data by employing the Hilbert transform to derive the analytic signal and the short-time Fourier transform (STFT) to generate a time–frequency representation. The proposed CVCNN framework effectively learns spatial-temporal features …

Improved Oscillation Criteria For A Class Of Neutral Differential Equations In The Canonical Case, Abdulaziz Khalid Alsharidi, Ali Muhib

Turkish Journal of Mathematics

This paper develops an analytical framework based on comparison with first-order equations to derive new oscillation criteria for all solutions of a class of second-order differential equations with multiple delays. These criteria extend and improve upon previously published results. Illustrative examples are provided to validate the theoretical findings and to demonstrate the significance and applicability of the proposed criteria.

Oscillation Properties Of First-Order Difference Equations With Nonmonotone Delays: New Insights And Criteria, Emad Attia, George Chatzarakis

Turkish Journal of Mathematics

In this paper, we examine the oscillatory behavior of the first-order linear delay difference equation Δy(n) + p(n) y(τ(n)) = 0, n ∈ ℕ₀. It is known in the literature that, for any C > 0, the condition lim sup_n→∞ ∑_i=τ(n)ⁿ p(i) > C, with τ(n) nonmonotone, is not, in general, sufficient to establish the oscillation of the difference equation. We prove that, for certain classes of difference equations, the aforementioned condition is sufficient to ensure the …