A new rhodamine B-based Schiff base (RSB) derivative was successfully synthesized via condensation of rhodamine B hydrazide with 5-bromo-2-hydroxybenzaldehyde and characterized using FT-IR spectroscopy, NMR, single-crystal X-ray diffraction, photophysical studies and in silico ADME analysis. FT-IR data confirmed the formation of the azomethine (C=N) functionality together with the preservation of the spirolactam ring structure. Single-crystal X-ray analysis revealed that the compound crystallizes in the triclinic crystal system with the centrosymmetric space group P-1. Structural analysis confirmed the closed spirolactam form and showed the presence of an intramolecular O–H···N hydrogen bond stabilizing the molecular conformation, while weak intermolecular C–H···O interactions contribute to the supramolecular architecture. Photophysical investigations in DMF solution demonstrated absorption bands at 307 and 348 nm, attributed to π→π* and n→π* transitions, respectively. Upon excitation at 498 nm, the compound exhibited green fluorescence emission centered at 513 nm. The observed optical behavior originates from the extended conjugated xanthene–hydrazone framework. Furthermore, the physicochemical and pharmacokinetic properties of the compound were evaluated using the SwissADME platform. The results indicated high lipophilicity, low gastrointestinal absorption, absence of blood–brain barrier permeability, and favorable intracellular retention characteristics. Although the compound does not fully satisfy conventional drug-likeness criteria due to its high molecular weight and lipophilicity, its strong fluorescence properties and predicted membrane affinity suggest that the synthesized RSB derivative may represent as a promising candidate for fluorescent imaging and sensing applications.
Type 2 diabetes mellitus is a chronic metabolic disorder characterized by impaired insulin activity and hyperglycemia, which often leads to severe complications. Current therapeutic agents such as acarbose exert their effects through α-glucosidase inhibition; however, their clinical utility is often restricted due to gastrointestinal side effects, highlighting the urgent need for safer and more effective alternatives. Phthalocyanines, known for their structural stability and versatile biological activities, represent promising candidates in this field. In this study, two previously synthesized water-soluble peripheral tetra-substituted metallophthalocyanine complexes, copper(II) phthalocyanine (CuPc) and manganese(III) phthalocyanine (MnPc), were evaluated for their α-glucosidase inhibitory potential using both in vitro and in silico approaches. The IC50 values of CuPc (14.90 ± 0.59 µM) and MnPc (12.91 ± 0.29 µM) were lower than that of acarbose (237.24 ± 1.80 µM), indicating stronger inhibitory effect in vitro. Kinetic studies revealed that MnPc displayed competitive inhibition with a Ki value of 1.88 µM. Molecular docking simulations further supported these findings, with binding affinities of −9.8 kcal/mol for CuPc and −9.3 kcal/mol for MnPc against α-glucosidase (PDB ID: 3WY2). Structural analyses showed that CuPc binding was dominated by hydrophobic and π-interactions, while MnPc formed an extensive hydrogen-bonding network in addition to hydrophobic contacts. These combined interactions may contribute to their observed binding affinity and inhibitory activity. Overall, the results indicate that CuPc and MnPc are potent in vitro α-glucosidase inhibitors and provide a basis for further investigation of these compounds as potential antidiabetic agents. However, additional in vivo efficacy, toxicity, and pharmacokinetic studies are required to further evaluate their therapeutic potential.
The aim of this work is to investigate the oscillatory behavior of a class of third-order neutral differential equations with multiple delays. By employing rigorous analytical techniques, we establish new sufficient conditions that guarantee the oscillation of all solutions of the considered equation. Computational simulations demonstrate the interaction effects caused by multiple delays. Furthermore, numerical experiments distinctly illustrate the pronounced interplay between the delays and uncover notable variations in the oscillation envelope, as well as shifts in the decay rate for specific parameter regimes.
This article is dealt with a Kirchhoff problem involving p(x) - biharmonic operator. By means of the Variational method and Ekeland’s variational principle, we establish the existence of a nontrivial weak solution in Sobolev spaces with variable exponent under some appropriate condition.
One of the most important strategies in the management of type 2 diabetes is controlling postprandial hyperglycemia, and α-glucosidase inhibitors are commonly used to achieve this. However, the side effects that may arise from the long-term use of synthetic inhibitors have increased interest in naturally derived alternatives. In this study, the α-glucosidase inhibitory activities of ethanol extracts from Thymus sipyleus Boiss., Salvia officinalis L., and Lavandula stoechas L. were evaluated in comparison with acarbose, a reference inhibitor. The results showed that all plant extracts examined exhibited strong inhibitory activity against α-glucosidase. The highest inhibitory activity was found in S. officinalis (IC50: 2.44±0.086 µg/mL); This was followed by T. sipyleus (2.71±0.40 µg/mL) and acarbose (2.85 ± 0.23 µg/mL). L. stoechas also exhibited significant but lower inhibitory activity (5.68 ± 0.05 µg/mL). The higher α-glucosidase inhibitory activity of S. officinalis and T. sipyleus extracts compared with acarbose suggests that these species may represent promising natural sources of α-glucosidase inhibitors. While the α-glucosidase inhibitory activity of S. officinalis has been previously reported, data regarding T. sipyleus and L. stoechas remain limited. This study provides novel comparative data on the α-glucosidase inhibitory activities of these three species and highlights their potential as promising natural sources of α-glucosidase inhibitors for further investigation.
Ankylosing spondylitis (AS) is a chronic inflammatory rheumatic disease characterized by persistent inflammation, oxidative stress, immune dysregulation, and abnormal bone remodeling. Recent evidence suggests that microRNA-mediated post-transcriptional regulation and DNA damage response pathways may contribute to AS pathogenesis. This study aimed to investigate the expression profiles of selected microRNAs and genes associated with inflammation, apoptosis, and DNA repair mechanisms in patients with AS. A total of 30 patients diagnosed with AS and 30 healthy controls were included in the study. Gene and microRNA expression levels, including miRNA-574-5p, miRNA-30c-5p, MDM2, RAD51, NFKB1, BAX, ERCC1, and ATR, were analyzed using quantitative real-time PCR (qRT-PCR). Inflammatory parameters, including C-reactive protein (CRP), erythrocyte sedimentation rate (ESR), and interleukin-6 (IL-6), were also evaluated. The results demonstrated significantly increased miRNA-574-5p expression and significantly decreased MDM2 expression in the AS group compared with controls (p<0.05). CRP and IL-6 levels were also significantly elevated in patients with AS. Logistic regression analysis identified miRNA-574-5p, MDM2, and CRP as independently associated with AS. Receiver operating characteristic (ROC) analysis revealed that miRNA-574-5p and MDM2 exhibited significant diagnostic performance for distinguishing AS patients from healthy individuals. Correlation analyses demonstrated a positive association between miRNA-574-5p and BAX, whereas a negative correlation was observed between miRNA-574-5p and ESR. These findings suggest that altered miRNA-574-5p and MDM2 expression may contribute to inflammatory activity, apoptosis, and cellular stress responses in AS. Overall, the findings suggest that altered miRNA-574-5p and MDM2 expression may be associated with ankylosing spondylitis and represent candidate molecular biomarkers that warrant further validation in larger independent cohorts.
Permutation‐based multivariate statistical techniques have received increasing popularity in animal science investigations, particularly for data sets that fail to satisfy classical parametric assumptions like multivariate normality and homoscedasticity of covariance matrices. In the framework of dairy production research, milk composition traits are largely determined by different types of management and season and require appropriate robust multivariate inference models. This work used Permutational Multivariate Analysis of Variance (PERMANOVA) to evaluate differences in composition of milk fed by Holstein cows, as a function of feeding systems and periods. Means of monthly averages of milk fat (%), dry matter (%) and protein were determined based on 30 Holstein cows which were reared in a private farm located in the Tokat Province, Türkiye during the period of 2024. The 2 types of feed consumption were divided into two groups, dry forage and green alfalfa; seasonality was assessed quarterly. Of theses, PERMANOVA models were fitted under both one-way and two-way experimental design with Euclidean, Bray–Curtis and Manhattan distance as alternative commonly used choices. Milk fat and dry matter differed significantly among feeding periods, however milk protein did not (P > 0.05). Furthermore, the more permutations were conducted, the more stable and robust significance results became, which is, large all distance measures reached generally consistent conclusion as long as enough permutation was used. Generally, the results support PERMANOVA as a flexible and reliable replacement for MANOVA in the analysis of multivariate dairy data, particularly demonstrating its effectiveness at assessing differences in milk composition due to feeding and seasonality under non-normal data scenarios.
Characterization and structural analysis of integral membrane proteins (IMPs) require detergents that can efficiently disrupt the lipid bilayer while maintaining the native conformation, solubility, and stability of the protein. Selecting an appropriate detergent therefore represents a critical bottleneck in membrane protein biochemistry. In this study, we systematically benchmarked six commonly used detergents—fos-choline-12 (FC-12), lauryldimethylamine-N-oxide (LDAO), n-dodecyl-β-D-maltoside (DDM), n-decyl-β-D-maltoside (DM), lauryl maltose neopentyl glycol (LMNG), and nonyl glucoside (NG)—to determine their suitability for the stabilization of a representative IMP. For each detergent, we assessed solubility, followed by an evaluation of oligomeric homogeneity using size-exclusion chromatography. Purity and yield were quantified to enable a comparative view of detergent-dependent protein recovery. To evaluate structural integrity and stability, we conducted circular dichroism spectroscopy and derived thermal unfolding profiles to assess melting temperatures. Our results reveal clear trade-offs between detergents that excel in membrane solubilization and those that better preserve conformational stability, with no single detergent outperforming across all metrics. While NG caused protein precipitation, other detergents maintained protein solubility but produced distinct SEC profiles and apparent thermal stabilities. LDAO and LMNG provided the highest apparent melting temperatures, while DM showed the lowest. These findings provide a practical framework for detergent selection and optimization, and offer broadly applicable insights for researchers pursuing structural, functional, or biophysical studies of other IMPs
Cotinus coggygria Scop. (C. coggygria) has been reported to contain numerous secondary metabolites. In the present study, in vitro total phenolic and flavonoid contents and antioxidant activity of C. coggygria extract were determined. In in vivo experiments, rats were divided into four groups. Total oxidant and antioxidant status, nitric oxide, reduced glutathione, lipid peroxidation, sialic acid, advanced oxidized protein product levels and carbonic anhydrase, aryl esterase, xanthine oxidase, lactate dehydrogenase, paraoxonase, prolidase, acetylcholinesterase enzyme activities and antioxidant and glutathione-related enzyme activities were determined in all brain tissue homogenates. According to the results, aqueous C. coggygria extract shows protective properties against ethanol-induced brain damage due to various bioactive components it contains and provides restoration of biochemical parameters. Considering the data from our study, C. coggygria can be used to prevent ethanol-induced oxidative stress in brain tissue due to its strong antioxidant activity.
Cisplatin is a potent chemotherapeutic agent, yet its clinical utility is often limited by systemic toxicity. Trimetazidine dihydrochloride (TMZ), a metabolic regulator used in cardiovascular medicine, has shown potential in modulating cellular stress and energy metabolism. The efficacy of TMZ against the HeLa cervical cancer cell line has not been previously investigated. This study aimed to investigate the cytotoxic effects of TMZ, both as a monotherapy and in combination with cisplatin, on HeLa cervical cancer cells and T0063 healthy human liver fibroblast cells. Cell viability was evaluated using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) colorimetric assay at 24, 48, and 72 hours. Cells were treated with varying concentrations (1-200 µM) of TMZ and cisplatin. The Selectivity Index (SI) was calculated to assess the differential impact on cancerous versus healthy cells. TMZ monotherapy exhibited negligible cytotoxicity across all time points (IC50 > 200 µM). Cisplatin monotherapy showed time-dependent cytotoxicity in HeLa cells. For combination treatments, the cell line- and time-specific fixed IC₅₀ doses of cisplatin were co-administered with varying concentrations of TMZ (1–200 µM). The co-administration of TMZ and cisplatin at 24 and 48 hours significantly enhanced cytotoxic activity in HeLa cells while simultaneously reducing cytotoxicity in T0063 cells. At 24 hours, the combination treatment increased the SI from 2.66 (cisplatin alone) to 9.91. Similar potential synergistic interaction and cytoprotective trends were observed at 48 hours; however, this synergy diminished by 72 hours. These findings provide the first evidence that TMZ potentiates the efficacy of cisplatin in HeLa cells while preserving the viability of healthy liver cells. TMZ represents a promising candidate for drug repurposing in combination treatments.
Apoptosis is essential for tissue homeostasis, and its dysregulation is a hallmark of cancer. The B-cell lymphoma-2 (Bcl-2) protein family, particularly known for its anti-apoptotic role, contributes to tumor survival and chemoresistance. Venetoclax, a selective Bcl-2 inhibitor, has shown notable clinical success; however, resistance and toxicity highlight the need for alternative strategies. This study aimed to explore the inhibitory potential of withdrawn drugs on Bcl-2 using in silico methods to identify candidates for repurposing in anticancer therapy. Withdrawn drugs were retrieved from the DrugBank database and screened via molecular docking using MzDOCK software, with venetoclax as the reference inhibitor. Compounds displaying higher or comparable affinities were analyzed for key interactions, including hydrogen bonds, hydrophobic contacts, and salt bridges within the Bcl-2 binding pocket. Plicamycin showed the strongest binding affinity (-11.5 kJ/mol), surpassing venetoclax (-10.3 kJ/mol). It not only shared common binding residues with the reference molecule but also formed additional stabilizing interactions. Other drugs, such as depreotide, piperacetazine, and phenolphthalein, also demonstrated favorable binding profiles, supporting the feasibility of repurposing withdrawn compounds. Several withdrawn drugs retain valuable scaffolds for targeting Bcl-2. Plicamycin, despite historical toxicity concerns, emerges as a strong candidate for further preclinical evaluation. Modern delivery systems, such as nanoparticle formulations, may improve efficacy while reducing adverse effects. These findings underscore the promise of computational drug repurposing for anticancer discovery and encourage re-examination of withdrawn drugs within contemporary therapeutic contexts.
The adsorption performance of natural bentonite (B) and magnetically modified bentonite (MB) for the removal of an anionic yellow dye (YD) from aqueous solution was comparatively investigated using a batch adsorption system. Magnetic bentonite was synthesized via the co-precipitation of Fe²⁺ and Fe³⁺ ions onto the bentonite surface, and the structural modifications were characterized by X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), and scanning electron microscopy (SEM). The characterization results confirmed the successful incorporation of Fe₃O₄ onto the bentonite surface while preserving the fundamental layered structure of bentonite and creating additional adsorption-active surface features. The effects of solution pH, adsorbent dosage, initial dye concentration, and temperature were systematically investigated to determine the optimum adsorption conditions. Adsorption equilibrium was evaluated using the Langmuir, Freundlich, Dubinin–Radushkevich (D–R), and Temkin isotherm models. Among the investigated models, the Langmuir isotherm provided the best fit to the experimental data, with correlation coefficients ranging from0.989 to 0.998for natural bentonite and0.985 to 0.999for magnetic bentonite, indicating predominantly monolayer adsorption. The maximum Langmuir adsorption capacities obtained at an adsorbent dosage of 0.1 g were333.3 mg g⁻¹for natural bentonite and312.5 mg g⁻¹for magnetic bentonite. The calculated separation factor (RL) values (0 < RL < 1) confirmed that adsorption was favorable under all investigated conditions. Thermodynamic analysis demonstrated that the adsorption process wasspontaneous. (ΔG < 0)andexothermic (ΔH < 0)for both adsorbents. Magnetic modification altered the surface characteristics of bentonite, promoted favorable adsorption behavior under different operating conditions, and enabled rapid magnetic separation after adsorption. Overall, both natural and magnetic bentonites exhibited effective adsorption performance, indicating their potential as economical and environmentally friendly adsorbents for the treatment of dye-contaminated wastewater.
Accurate prediction of drug efficacy and cytotoxicity for SARS-CoV-2 is a critical step in early-stage drug development, guiding compound prioritization and identifying potential therapies. Ensemble-based algorithms such as Random Forest have demonstrated strong predictive performance in this domain; however, their reliance on post hoc interpretability methods like SHAP (Shapley Additive Explanations) often yields complex, global explanations of feature importance rather than simple, actionable rules. To enhance direct interpretability while maintaining competitive predictive accuracy, this study applies Multivariate Adaptive Regression Splines (MARS), a nonparametric modeling framework that provides rule-based transparency, to a carefully prepared SARS-CoV-2 dataset integrating network and physicochemical features. Comparative receiver operating characteristic (ROC) analyses demonstrated that MARS achieved consistently strong discriminative ability in cytotoxicity-focused models, while showing relatively moderate performance for efficacy-related classification. These findings reveal a trade-off between interpretability and predictive performance, suggesting that while simpler, transparent models can effectively capture determinants of cytotoxicity, they may generalize less efficiently for efficacy prediction. Overall, this study highlights the potential of intrinsically interpretable machine learning frameworks such as MARS for generating clear, mechanistic insights into drug safety profiles.
The optical absorption improvement in CIGS absorber thin film is a critical phenomenon. In this study, the effect of the set film thickness and working gas pressure on the absorption properties of CIGS thin films was studied. CIGS films were RF sputtered at high (15 mTorr) and low (5 mTorr) pressure with different set thicknesses of 200 nm, 400 nm and 600 nm. It was demonstrated that, as expected, the absorption increases with film thickness. Meanwhile, the higher absorption is observed for the films grown at high pressure compared to low pressure grown counterparts at all film thickness which is believed due to the porous film nature of the former films. At high pressure sputter, the films with higher porosity and more rough film surfaces, which was determined by SEM and AFM roughness imaging, were obtained, which results in higher optical absorption. It was shown that by simply tuning the Ar gas pressure slightly during sputtering, the absorption can be improved at a reasonable rate.
Chronic glomerular and tubulointerstitial fibrosis represents a major pathological process leading to end-stage renal failure. Mesenchymal stem cell (MSC) therapy has emerged as a promising approach for renal tissue repair. The identification of molecular markers associated with disease progression may contribute to the evaluation of therapeutic responses. Adiponectin has been suggested as a potential indicator in chronic kidney injury. The present study aimed to investigate adiponectin-related molecular changes following MSC therapy in a rat model of chronic renal injury. Mesenchymal stem cells were isolated from the amniotic membrane of term placentas. Chronic renal injury was induced in rats by subtotal (5/6) nephrectomy. MSCs were administered via the tail vein, and animals were evaluated at 15 and 30 days after transplantation. Protein and mRNA expression levels of adiponectin, adiponectin receptor 1, fibronectin, and phosphorylated AMP-activated protein kinase (AMPK) were assessed using Western blotting and real-time PCR. Serum and urinary adiponectin levels, as well as urinary albumin levels, were measured by rat-specific ELISA kits. Compared to control animals, nephrectomized rats exhibited increased expression levels of adiponectin, adiponectin receptor 1, fibronectin, and phosphorylated AMPK. Following MSC administration, these molecular alterations showed a declining trend. In parallel, urinary albumin levels were reduced in MSC-treated groups. The findings suggest that MSC therapy is associated with modulation of adiponectin-related molecular pathways in chronic renal injury. Adiponectin-associated changes may provide preliminary insight into molecular responses during disease progression; however, further studies are required to clarify its utility as a definitive biomarker.
Hemorrhagic shock is a major cause of trauma-related mortality, yet the contribution of the gut microbiome to systemic fluid and electrolyte regulation during acute blood loss remains unclear. This study investigated whether maternal antibiotic-induced dysbiosis alters the osmoregulatory and metabolic responses of offspring to hemorrhagic shock. Pregnant and lactating Sprague Dawley dams received vancomycin and amoxicillin, and antibiotic treatment was continued in male offspring until 8 weeks of age. Following a 4-week washout period, 12-week-old offspring underwent fixed-volume hemorrhagic shock (1.5 mL/100 g body weight), and serum biochemical variables and organ wet weights were evaluated. Compared with controls, dysbiotic offspring exhibited persistent hypernatremia and hyperchloremia (both p < 0.001), together with significantly higher calculated serum osmolarity (p = 0.030). These alterations were accompanied by significantly lower blood urea nitrogen and creatinine concentrations (p < 0.01), suggesting an attenuated metabolic and renal adaptive response. Lung and brain wet weights were also significantly lower in dysbiotic offspring (p = 0.002 and p = 0.01, respectively), whereas kidney and heart wet weights were unaffected. These findings suggest that maternal antibiotic-induced dysbiosis is associated with impaired systemic electrolyte regulation and organ-specific physiological responses during hemorrhagic stress. Clinically, closer monitoring of serum sodium and osmolarity may be warranted in trauma patients with a history of prolonged antibiotic exposure.
The design of dual inhibitors of acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) enzymes is a highly significant strategy in the treatment of Alzheimer’s disease. In this study, six new thiosemicarbazone-carbamate derivatives (8a-c, 9a-c) were designed and synthesized, based on vanillin and isovanillin, as potential dual inhibitors of cholinesterases for the treatment of Alzheimer’s disease. In vitro biological activity assessments revealed that the synthesized compounds had greater potential to inhibit BChE than AChE. Compound 8a, which emerged as the most potent BChE inhibitor in the series, exhibited 81.49% inhibition at 100 µM and an IC50 of 58.41 µM, inhibiting the enzyme via a non-competitive mechanism, whilst compound 9c exhibited the highest AChE inhibition at the same concentration, with a rate of 40.27%. Molecular docking simulations supported the biological findings by confirming that the active compounds form hydrogen bonds and π-π interactions with critical amino acids in the catalytic sites of both enzymes. Furthermore, the in silico pharmacokinetic analyses conducted revealed that all derivatives possess a drug-like profile and exhibit high blood-brain barrier permeability scores (4.00–4.01), indicating their potential to reach the central nervous system.
In many engineering systems, component failure arises from the interaction between time-varying resistance and random environmental stress. Classical formulations usually assume static resistance and independent components, assumptions often violated in practice. We develop a stochastic framework for parallel and consecutive 𝑘-out-of-𝑛:𝐹 systems in which component resistances follow linear degradation paths with random deterioration rates, while all components are exposed to a common random stress. Dependence among deterioration rates is modelled via a copula, yielding joint lifetime distributions for parallel systems; for consecutive 𝑘-out-of-𝑛:𝐹 structures, maximal signatures express system lifetimes in terms of parallel-system survival. Numerical illustrations with a survival Clayton copula and Weibull marginal deterioration (decreasing, constant, and increasing hazard) examine the impact of dependence strength and marginal failure behaviour on reliability and mean residual life. We also analyse an optimal replacement policy that minimises long-run average cost and compare maintenance decisions under independent and dependent deterioration. The results show that ignoring dependence systematically underestimates failure risk and cost, and that preventive replacement is economically justified only for components with increasing failure rates, whereas constant or decreasing hazard rates favour run-to-failure strategies.
In this study, titanium dioxide TiO₂ thin films were deposited onto glass substrates at room temperature and at a substrate temperature of 300°C using the RF magnetron sputtering technique, and their structural, morphological, chemical, and photocatalytic properties were comparatively investigated. XRD analysis revealed that the film deposited at room temperature exhibited a fully amorphous structure, whereas the film deposited at 300°C displayed low-intensity reflections of the anatase (101) and (004) planes on an amorphous background, indicating the onset of limited crystalline nucleation with increasing temperature. Cross-sectional SEM images confirmed the formation of a homogeneous layer with an approximate thickness of 330 nm, while surface SEM micrographs showed a compact and fine-grained morphology characteristic of films deposited at low temperatures. AFM measurements demonstrated a granular surface topography with an RMS roughness of approximately 26 nm over a 10 × 10 µm scan area. FTIR spectra revealed the characteristic Ti–O–Ti vibrational modes, confirming the formation of the TiO₂ network structure. Photocatalytic experiments showed that the TiO₂ film deposited at 300°C achieved approximately 74% degradation of methylene blue under UVA irradiation after about 9 hours, exhibiting significantly higher photocatalytic activity compared to the room-temperature film. This improvement is attributed to partial structural ordering and increased surface roughness. Overall, the findings demonstrate that the structural evolution occurring in TiO₂ thin films deposited at low temperatures directly influences their photocatalytic behavior, and that TiO₂ films exhibiting considerable photocatalytic performance can be produced even at moderate deposition temperatures such as 300°C.
The great success of optical fibers in telecommunications today has been extended to the success of their rare-earth doped versions in medical applications, sensing technologies, high-power lasers, and amplifiers. The advantages such as excellent beam quality, high power capability, and cost-effectiveness, are increased to be widespread in high technological applications. However, exposure to ionizing radiation leads to degradation of these properties, significantly restricting the deployment of optical fibers in radiation-rich environments such as nuclear power facilities and space applications.In the present study, ytterbium-doped optical fibers were irradiated with the Co-60 gamma source using total doses of 0.5, 1, 10, and 50 kGy at a dose rate of 1.19 kGy/h. Radiation-induced attenuation (RIA) was measured at room temperature before and after irradiation. Optical transmission spectra were recorded over a broad wavelength range from 300 to 1000 nm, and RIA values at selected wavelengths (450, 560, 625, and 730 nm) were extracted. After irradiation at a total dose of 50 kGy, the formation of dopant-related color centers, including Al-OHC, POHC, and NBOHC, was observed in the optical fibers. Post-irradiation recovery behavior was monitored over periods ranging from one to three weeks. Additionally, radiation-induced variations in the refractive index of the fiber core were investigated by measuring the numerical aperture (NA) of the fibers.
