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İstanbul Kent Üniversitesi Research and Academic Performance System

DSpace@Kent is an integrated information system that unifies the monitoring, analysis and reporting of scientific research and academic performance at İstanbul Kent University.

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Recent Submissions

Quadruple isotope dilution versus conventional calibration methods for accurate urinary hippuric acid quantification with a synthesized isotopically labelled material
(Springer Nature, 26/10/2026)
Atakol, Arda
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Bodur, Süleyman
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Eroğlu, Kumsal
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Günkara, Ömer Tahir
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Bakırdere, Sezgin
Hippuric acid is a key biomarker in toxicological and metabolic investigations. This study presents an accurate UHPLC-MS/MS method for the quantification of hippuric acid in urine matrix. A quadruple isotope dilution (ID4 ) strategy was utilized to compensate possible matrix effects and variations in calibration and increase accuracy. Hippuric acid–d₅ was synthesized in-house from glycine and benzoyl chloride–d₅, lowering material costs to easily affordable levels. The mass spectrometry and chromatographic parameters were optimized for improved sensitivity and separation. After the optimization experiments, the analytical performance of the UHPLC-MS/MS system was evaluated. The developed method exhibited a wide linear range from 55.80 ng/ kg to 530.10 µg/kg, with limit of detection (LOD) of 15.6 ng/kg and limit of quantification (LOQ) of 52.1 ng/kg. The method was validated with a certified reference material and gradient spiked recovery runs in the same matrix, resulting in excellent agreement with the certified value and consistent recoveries. Results were put into comparison with more conventional techniques of external standard (ES) calibration and single–point isotopically labelled standard addition which demonstrated the superiority of the ID4 method. The proposed method is intended as a candidate reference procedure for hippuric acid in urine, and it can be used to assign values to quality control and calibration materials for routine LC-MS/MS methods. In addition, the in-house synthesis of hippuric acid-d5 makes this approach affordable for laboratories outside metrology institutes.
Design of Plant Oil-Based Cationic Hydrogels for Protein Encapsulation and Controlled Delivery
(Springer Nature, 05/5/2026)
Atakol, Arda
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Maaz, Asmaa
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Çaylı, Gökhan
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Giray, Betül
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Erdem, Ahmet
The development of sustainable multifunctional hydrogels with antibacterial activity and protein delivery capability is of great interest for biomedical applications. In this study, plant oil-derived cationic hydrogels were developed by UV-induced polymerization using acrylated methyl ricinoleate (AMR), a renewable monomer derived from castor oil, and 2-aminoethyl methacrylate (AEMA). The influence of hydrogel composition on morphology, pH-responsive swelling, antibacterial activity, cytocompatibility, and protein encapsulation behavior was investigated. FTIR and SEM analyses confirmed successful hydrogel formation and revealed composition-dependent structural differences. The swelling behavior was strongly influenced by pH and monomer ratio. The hydrogels exhibited significant antibacterial activity against Escherichia coli and Staphylococcus aureus while maintaining good cytocompatibility toward human umbilical vein endothelial (HUVEC) cells, with cell viability exceeding 80%. Bovine serum albumin (BSA) was used as a model protein to evaluate encapsulation and release properties. Protein encapsulation efficiency was found to depend strongly on crosslinking density, with lower crosslinking ratios leading to enhanced loading. Overall, the results demonstrate that combining a renewable plant oil-derived monomer with a cationic component enables the fabrication of sustainable hydrogels with tunable physicochemical and biological properties, highlighting their potential for wound healing and localized protein delivery applications.
An examination of future anxiety among vocational school students in relation to sociodemographic variables
(Springer Nature, 05/11/2026)
Kartal, Neslihan
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Mehel Tutuk, Sevda Pinar
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Gürün Betbaşi, Reyhan
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Kurt, Şebnem
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Unluturk, Şerife
Aim This study aimed to examine future anxiety among vocational school students and to determine whether its dimensions differ according to sociodemographic and lifestyle characteristics. Materials and methods This descriptive cross-sectional study included 255 vocational school students aged 18–35 years. Data were collected using a Sociodemographic Data Form and the Future Anxiety Scale in Uni versity Students. The Cronbach’salpha coefficient of the total scale was .93 in the present study. Descriptive statistics, independent-samples t tests, and one-way analysis of variance (ANOVA) were used for data analysisResults The mean total Future Anxiety Scale score was 55.47 ± 15.26. Significant differences were observed in selected dimensions of future anxiety according to age, marital status, economic status, regular hobby engage ment, regular exercise, family financial support, academic department, and dietary habits. Poor perceived eco nomic status was associated with higher Fear of the Future and Hopelessness About the Future scores. Conclusion Selected sociodemographic, economic, and lifestyle characteristics were associated with specific dimensions of future anxiety among vocational school students. The findings highlight the importance of psycho social and career-support services for students experiencing economic and future-related uncertainty.
Need for Social Approval and Resilience-Related Protective Factors in Adults Who Stutter: A Comparative and Correlational Study
(MDPI, 27/10/2026)
Alpüran Kocabıyık, Nurcan
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Erkal, Sultan
Stuttering is associated with psychosocial challenges that may increase vulnerability to social evaluation. This study examined whether adults who stutter (AWS) differ from adults who do not stutter (AWNS) in their need for social approval and investigated the relationship between social approval and resilience-related protective factors in AWS. The final analytic sample comprised 126 adults aged 18–49 years (69 AWS and 57 AWNS). No statistically significant differences were detected in sex or age-category distributions; these tests were used to describe demographic comparability and were not interpreted as evidence of statistical equivalence. Participants completed the Need for Social Approval Scale and the Protective Factors for Psychological Resilience Scale. AWS had a significantly higher total need for social approval than AWNS (76.90 ± 18.93 vs. 67.75 ± 16.10), t(124) = 2.885, p = 0.005, Hedges’ g = 0.513, bootstrap 95% CI [0.17, 0.91]. Within AWS, total need for social approval was moderately and inversely associated with total resilience-related protective factors (Spearman ρ = −0.429, p < 0.001, bootstrap 95% CI [−0.620, −0.192]; Holm-adjusted p = 0.003). In an age- and sex-adjusted sensitivity analysis using all eligible participants aged 18–49 years (69 AWS and 82 AWNS), AWS status remained associated with higher total social approval scores (B = 8.50, 95% CI [1.99, 15.02], p = 0.011). These findings describe associations between approval-oriented social concerns and perceived protective resources; the cross-sectional design does not establish causal mechanisms or intervention targets.
Comparative Evaluation of Children with and Without Speech Disorders Utilizing the Nordic Orofacial Test-Screening and Kotlow’s Classification System
(MDPI, 22/10/2026)
Alpüran Kocabıyık, Nurcan
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Dayan, Elis
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Özkuyucu, Deniz
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Balaban, Melike
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Oğuzbal, Emre
Background: Orofacial dysfunction may co-occur with speech and language disorders. This study compared orofacial function in children with and without speech disorders using the Nordic Orofacial Test-Screening (NOT-S) and examined whether Kotlow tongue-tie severity is associated with orofacial function. Methods: This cross-sectional study included 77 children aged 5–13 years (37 with speech and language disorders [SD]; 40 without [N]). Orofacial function was screened with the NOT-S, and free tongue length was classified according to Kotlow. Nonparametric and exact tests, Poisson regression adjusted for age, sex, and systemic conditions, and sensitivity analyses were used. Results: The SD group had higher NOT-S total (median 3 vs. 1; p < 0.001; r = 0.50) and examination scores (p < 0.001; r = 0.76) than the N group, whereas interview scores did not differ. After Holm correction, facial expression, oral motor function, and speech remained more frequently impaired. The difference persisted after adjustment (incidence rate ratio 2.21, 95% CI 1.53–3.19), in children without systemic conditions, and after exclusion of the speech domain. Tongue-tie prevalence and free tongue length did not differ between groups, and no severity-related association with NOT-S scores emerged. Conclusions: Children with speech disorders had higher NOT-S scores, which persisted after adjustment for age, sex, and systemic conditions, whereas no statistically significant association between tongue-tie severity and orofacial function was demonstrated in this small sample, which does not rule out an effect. Anatomical frenulum assessment alone may be insufficient and should be complemented by functional and speech and language evaluation.