Nilüfer KOÇAK ŞAHİN

Dr. Nilüfer KOÇAK ŞAHİN

orcid

Research Focus & Metrics

Academic Career Length

21Years (2006-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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1 January 2020 in Ciência E Agrotecnologia
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Journal Article
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HAHussein Abdullah Ahmed Ahmed
Hussein Abdullah Ahmed Ahmed
NŞNilüfer KOÇAK ŞAHİN
Nilüfer KOÇAK ŞAHİN
GAGuray Akdogan
Guray Akdogan
CYCennet Yaman
Cennet Yaman
DKDeniz Köm
Deniz Köm
SUSerkan Uranbey
Serkan Uranbey
Salinity is one of the abiotic stresses that lead to an imbalance in the physiological processes of the plants and also affects potato growth and productivity in maınly semi-arid and growing areas. The accumulation of Na+ and Cl- ions in the cells is very toxic can influence all mechanisms and the enzymatic actions of the plants. In vitro screening of plant genotypes for osmotic stress represents a valuable tool as an alternative to field trials and can be applied based on osmotic stress tolerance. The main goal of this study was to reveal variability in salinity stress tolerance of potato varieties using in vitro screening. Stem cuttings consisting of a single node of different varieties were cultured on Murashige and Skoog (MS) medium supplemented with different concentrations of sodium chloride (NaCl) (0, 50, 100 and 150 mM). The differences among the plantlet length, number of branches, number of nodes, number of the leaflet, leaflet width, leaflet length, root length, number of the root, fresh plantlet weight, dry plantlet weight of all varieties were negatively influenced by all NaCl concentrations tested. Microtuberization and stolon growth of the varieties were also completely inhibited at high concentrations (100-150 mM). The Principal components analysis (PCA) was applied to the data matrix (15 morphological characteristics x 12 potato varieties) of the potato varieties. Also, a hierarchical cluster analysis (HCA) was used to identify the possible nearest and similarity of all morphological characteristics analyzed of the potato varieties. In grouping potato varieties, HCA and PCA results were found to be similar. We can speculate about the responses of morphological similarities of the potato varieties against salt stress. We concluded that Innovator and Kennebec are respectively the most salt-tolerant varieties. Hermes was moderately salt-tolerant and microtuberization capacity of Slaney was also high under salt stress conditions.

21 August 2018 in Ophthalmologica
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Journal Article
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MKMahmut Kaya
Mahmut Kaya
DKDERYA KAYA
DERYA KAYA
EIEgemen Idiman
Egemen Idiman
NŞNilüfer KOÇAK ŞAHİN
Nilüfer KOÇAK ŞAHİN
TOTaylan Ozturk
Taylan Ozturk
SKSuleyman Kaynak
Suleyman Kaynak
Purpose: To determine whether serum chitinase-3-like protein 1 (CHI3L1) and interleukin-6 (IL-6) levels correlate with serous retinal detachment (SRD) in diabetic macular edema (DME) using spectral-domain optical coherence tomography (SD-OCT). Methods: In this cross-sectional case-control study, 394 patients (treatment-naive DME patients, n = 218; diabetic patients without DME, n = 96; nondiabetic controls, n = 80) were included in the study. Eyes were classified according to SD-OCT features of DME: SRD, cystoid macular edema (CMO), and diffuse retinal thickness (DRT). Serum concentrations of CHI3L1 and IL-6 were analyzed using enzyme-linked immunosorbent assay. Results: Serum CHI3L1 and IL-6 levels were significantly higher in DME with SRD compared to patients with CMO and DRT (p < 0.001 for all groups). Multivariate regression analysis showed that CHI3L1 and IL-6 had a stronger influence on the presence of SRD in DME (r = 1.162, p = 0.026, and r = 1.242, p = 0.016, respectively). Serum concentration of CHI3L1 was significantly correlated with that of IL-6 (r = 0.386, p = 0.0015). Conclusions: Our data suggest that serum concentrations of CHI3L1 and IL-6 are involved in the process of SRD in DME. CHI3L1 can be investigated further as a new diagnostic biomarker for DME with SRD.

11 June 2025 in Processes
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OOOnur Okumuş
Onur Okumuş
Özhan ŞimşekÖzhan Şimşek
Özhan Şimşek
Musab A. IsakMusab A. Isak
Musab A. Isak
NŞNilüfer KOÇAK ŞAHİN
Nilüfer KOÇAK ŞAHİN
AAAdnan Aydin
Adnan Aydin
Mehmet YamanMehmet Yaman
Mehmet Yaman
Drought and temperature extremes are major abiotic stressors limiting legume productivity worldwide. This study investigates the germination and early seedling responses of six cultivars belonging to three Vicia species (V. sativa, V. pannonica, and V. narbonensis) under varying levels of polyethylene glycol (PEG)-induced drought and temperature conditions (12 °C, 18 °C, and 24 °C) in vitro. Significant cultivar-dependent differences were observed in the germination rate (GR), shoot and root length (SL and RL), fresh and dry weight (FW and DW), and vigor index (VI). The Ayaz cultivar exhibited superior performance, particularly under severe drought (10% PEG) and optimal temperature (24 °C), while Özgen and Balkan were most sensitive to stress. Principal component and correlation analyses revealed strong associations between the vigor index, shoot height, and fresh and dry weight, particularly in high-performing genotypes. To further model and predict stress responses, four machine learning (ML) algorithms—Random Forest (RF), k-Nearest Neighbors (k-NNs), Multilayer Perceptron (MLP), and Support Vector Machines (SVMs)—were employed. Based on model performance metrics, and considering high R2 values along with low RMSE and MAE values, the MLP model demonstrated the most accurate predictions for the GR (R2 = 0.95, RMSE = 0.06, MAE = 0.05) and VI (R2 = 0.99, RMSE = 0.02, MAE = 0.01) parameters. In contrast, the RF model yielded the best results for the SL (R2 = 0.98, RMSE = 0.02, MAE = 0.02) and DW (R2 = 0.93, RMSE = 0.06, MAE = 0.04) parameters, while the highest prediction accuracy for the RL (R2 = 0.83, RMSE = 0.09, MAE = 0.07) and FW (R2 = 0.97, RMSE = 0.05, MAE = 0.03) parameters was achieved using the SVM model. Comparative analysis with recent studies confirmed the applicability of ML in stress physiology and genotype screening. This integrative approach offers a robust framework for genotype selection and stress tolerance modeling in legumes, contributing to developing climate-resilient crops.

12 January 2023 in Current Eye Research
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Journal Article
Closed access
MKMahmut Kaya
Mahmut Kaya
FAFerdane Atas
Ferdane Atas
NŞNilüfer KOÇAK ŞAHİN
Nilüfer KOÇAK ŞAHİN
TOTaylan Ozturk
Taylan Ozturk
ZAZiya Ayhan
Ziya Ayhan
SKSuleyman Kaynak
Suleyman Kaynak
To compare efficacy of simultaneously administered intravitreal dexamethasone implant (DEX implant) and ranibizumab (simultaneous double protocol) injections with ranibizumab monotherapy for diabet...

1 December 2019 in Turkish Journal of Ophthalmology
Verified
Journal Article
Open access
NŞNilüfer KOÇAK ŞAHİN
Nilüfer KOÇAK ŞAHİN
MKMahmut Kaya
Mahmut Kaya
TOTaylan Ozturk
Taylan Ozturk
VBVolkan Bolluk
Volkan Bolluk
SKSüleyman Kaynak
Süleyman Kaynak
Objectives: To describe results of demarcation laser photocoagulation in preventing progression of subclinical retinal detachment (SCRD). Materials and Methods: Twenty-one eyes of 20 patients with SCRD were included. All patients underwent a complete ophthalmological examination, spectral-domain optical coherence tomography, and color fundus photography. Ages at initial diagnosis ranged between 18 and 75 years (mean: 57.3 +/- 16.2 years). Patients followed for at least 6 months were included in the study. Periodic retinal examinations were performed over follow-up periods of 6-55 months using Goldmann three-mirror contact lens and sometimes semilunar mirror lens with scleral indentation. Results: Twelve patients (60%) were female, eight (40%) were male. The mean follow-up period was 24.3 +/- 15.2 months (6-55 months). Three (14.3%) eyes were pseudophakic. One patient was affected bilaterally, with both eyes each containing two separate areas of involvement. The SCRD was in the upper quadrant of 18 eyes (85.7%) and the lower quadrant in 3 eyes (14.3%), and was located in the temporal region 10 eyes (47.6%), the nasal quadrant in 4 eyes (19.1%), and in the upper quadrant (temporal-nasal) in 7 eyes (33.3%). Six eyes (28.6%) were found to have myopia greater than -3.0 diopters. Progression to clinical retinal detachment was observed in 4/21 SCRD eyes (19%). All eyes showing progression to clinical retinal detachment had >-3.0 diopter myopia and multiple retinal tears located in the upper quadrant. Conclusion: Demarcation laser photocoagulation should be kept in mind as a first-line treatment for eyes with SCRD. Laser photocoagulation is vital in preventing progression to rhegmatogenous retinal detachment in most patients. After this treatment, these patients should be followed closely.

1 September 2006 in Annals of Ophthalmology
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Journal Article
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NŞNilüfer KOÇAK ŞAHİN
Nilüfer KOÇAK ŞAHİN
ASAli Osman Saatci
Ali Osman Saatci
FBFatma Meltem Soylev Bajin
Fatma Meltem Soylev Bajin