Reparative, Neuroprotective and Anti-neurodegenerative Effects of Granulocyte Colony Stimulating Factor in Radiation-Induced Brain Injury Model

Gökhan Gürkan,Özüm Atasoy,Nilsu Çini,İbrahim Halil Sever,Bahattin Özkul,Gökhan Yaprak,Cansın Şirin,Yiğit Uyanıkgil,Ceren Kızmazoğlu,Mümin Alper Erdoğan,Oytun Erbaş 대한신경외과학회 2023 Journal of Korean neurosurgical society Vol.66 No.5

Objective : This animal model aimed to compare the rat group that received brain irradiation and did not receive additional treatment (only saline) and the rat group that underwent brain irradiation and received Granulocyte colony stimulating factor (G-CSF) treatment. In addition, the effects of G-CSF on brain functions were examined by magnetic resonance (MR) imaging and histopathologically. Methods : This study used 24 female Wistar albino rats. Drug administration (saline or G-CSF) was started at the beginning of the study and continued for 15 days after whole-brain radiotherapy (WBRT). WBRT was given on day 7 of the start of the study. At the end of 15 days, the behavioral tests, including the three-chamber sociability test, open field test, and passive avoidance learning test, were done. After the behavioral test, the animals performed the MR spectroscopy procedure. At the end of the study, cervical dislocation was applied to all animals. Results : G-CSF treatment positively affected the results of the three-chamber sociability test, open-space test and passive avoidance learning test, cornu Ammonis (CA) 1, CA3, and Purkinje neuron counts, and the brain levels of brain-derived neurotrophic factor and postsynaptic density protein-95. However, G-CSF treatment reduced the glial fibrillary acidic protein immunostaining index and brain levels of malondialdehyde, tumor necrosis factor-alpha, nuclear factor kappa-B, and lactate. In addition, on MR spectroscopy, G-CSF had a reversible effect on brain lactate levels. Conclusion : In this first designed brain irradiation animal model, which evaluated G-CSF effects, we observed that G-CSF had reparative, neuroprotective and anti-neurodegenerative effects and had increased neurotrophic factor expression, neuronal counts, and morphology changes. In addition, G-CSF had a proven lactate-lowering effect in MR spectroscopy and brain materials.

The Role of 5G for Digital Healthcare against COVID-19 Pandemic: Opportunities and Challenges

Yushan Siriwardhana,Gürkan Gür,Mika Ylianttila,Madhusanka Liyanage 한국통신학회 2021 ICT Express Vol.7 No.2

COVID-19 pandemic caused a massive impact on healthcare, social life, and economies on a global scale. Apparently, technology has a vital role to enable ubiquitous and accessible digital health services in pandemic conditions as well as against “re-emergence” of COVID-19 disease in a post-pandemic era. Accordingly, 5G systems and 5G-enabled e-health solutions are paramount. This paper highlights methodologies to effectively utilize 5G for e-health use cases and its role to enable relevant digital services. It also provides a comprehensive discussion of the implementation issues, possible remedies and future research directions for 5G to alleviate the health challenges related to COVID-19.

Experimental and numerical assessment of the improvement of the load-carrying capacities of butterfly-shaped coupling components in composite structures

Gürkan Altan,Muzaffer Topçu 대한기계학회 2010 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.24 No.6

This study was designed to analyze the load-carrying capacities of composite structures connected face-to-face by a butterfly coupling component experimentally and numerically without adhesive. The results of the experimental studies were supported with numerical analysis. In addition, the butterfly coupling component was developed geometrically with a view to the results of the numerical and experimental studies. The change in the load-carrying capacity of the improved butterfly coupling components was analyzed numerically and experimentally to obtain new results. Half-specimens and butterfly-shaped lock components were cut with a water jet machine. Experiments and analyses were conducted to analyze the effects of coupling geometry parameters, such as the ratio of the butterfly end width to the specimen width (w/b), the ratio of the butterfly middle width to the butterfly end width (x/w), and the ratio of the butterfly half height to the specimen width (y/b). It was intended to determine the damage in the butterfly before any damage to the composite structure and to increase the service-life span of the composite structure with the repair of the butterfly lock. As a result of this study, it was determined that the geometrical fixed ratios (w/b) and (x/w) were 0.4 and 0.2 at 0.4 of (y/b) according to the experimental and numerical studies with basic and modified models.

Elastic-plastic thermal stress analysis of an aluminum composite disc under parabolic thermal load distribution

Gürkan Altan,Muzaffer Topçu,Numan Behlül Bektaş,Burçin Deda Altan 대한기계학회 2008 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.22 No.12

An elastic-plastic thermal stress analysis was carried out on an orthotropic aluminum metal matrix composite disc with a hole by using an analytical solution. The thermal load distribution was chosen to vary parabolically from inner surface to outer surface. An aluminum composite disc reinforced curvilinearly by steel fibers was produced under hydraulic press. The mechanical properties of the composite disc were obtained from experiments by using strain gauges. A computer program was developed to calculate the thermal stresses under a parabolic temperature from inner surface to outer surface. The material was assumed to be non-linear hardening. The elastic-plastic solution was performed for the plastic region expanded around the inner surface by an analytical method. The magnitude of the tangential stress component for elastic and elastic-plastic was higher than the magnitude of the radial stress component. Besides, the tangential stress component was compressive on the inner surface and tensile on the outer surface. The magnitude of the tangential residual stress component was the highest on the inner surface of the composite disc. The plastic region began at the inner surface of disc.

The Effects of Etodolac, Nimesulid and Naproxen Sodium on the Frequency of Sister Chromatid Exchange after Enclused Third Molars Surgery

Banu Gürkan Köseoğlu,Hülya Koçak,Şükrü Öztürk,Şükrü Palanduz,Kıvanç Çefle 연세대학교의과대학 2008 Yonsei medical journal Vol.49 No.5

Purpose: Non-steroidal anti-inflammatory drugs (NSAID) are frequently used in oral surgical procedures in dentistry. The evaluation of the frequency of sister chromatid exchange (SCE) is accepted as a reliable cytogenetic method to assess the genotoxic effects of environmental factors. Materials and Methods: In this study, the genotoxic effects of various NSAIDs were assessed in 30 patients to who they were administered following encluosed third molar surgery using SCE analysis before and after the operation. The frequency of SCE was evaluated before the operation and after 3 days of etodolac, nimesulid and naproxen use. Results: There was no statistically significant difference in the frequency of SCE between the preoperative and postoperative states in patients given etodolac, nimesulid or naproxen sodium. Conclusion: Short term use of selective and non-selective NSAIDs was not associated with a significant genotoxic effect that could be detected using the SCE method in peripheric lymphocytes.

The Investigation of a Novel Indicator System for Trace Determination and Speciation of Selenium in Natural Water Samples by Kinetic Spectrophotometric Detection

Ramazan GÜRKAN,Halil İbrahim ULUSOY 대한화학회 2010 Bulletin of the Korean Chemical Society Vol.31 No.7

A novel catalytic kinetic method is proposed for the determination of Se(IV), Se(VI) and total inorganic selenium in water based on the catalytic effect of Se(IV) on the reduction of bromate by p-nitrophenylhydrazine at pH 3.0. The generated bromine, Br2 or Cl2 plus Br2 in 0.1 M NaCl (or NaBr) environment efficiently decolorized Calmagite and the reaction was monitored spectrophotometrically at 523 nm as a function of time. In this indicator reaction, bromide acted as an activator for the catalysis of selenium (IV) and a reducing agent for selenium (VI) at pH 3.0, which allowed the determination of total selenium. The fixed time method was adopted for the determination and speciation of inorganic selenium. Under the optimum conditions, the calibration graph are linear in the range 1 - 35 μg L‒1 of Se(IV) for the fixed time method at 25 oC. The detection limit based on statistical 3Sblank/m-criterion was 0.215 μg L‒1for the fixed time method (7 min). All of the variables that affect the sensitivity at 523 nm were investigated, and the optimum conditions were established. The interference effect of various cations and anions on the Se (IV) determination was also studied. The selectivity of the selenium determination was greatly improved with the use of the strongly cation exchange resin such as Amberlite IR120 plus. The proposed kinetic method was validated statistically and through recovery studies in natural water samples. The RSDs for ten replicate measurements of 5, 15 and 25 μg L‒1of Se(IV) and Se(VI) was changed between 2.1 - 4.85%. Analyses of a certified standard reference material (NIST SRM 1643e) for selenium using the fixed-time method showed that the proposed kinetic method has good accuracy. Se(IV), Se(VI) and total inorganic selenium in environmental water samples have been successfully determined by this method after selective reduction of Se(VI) to Se(IV).

Long-term results of radiofrequency and microwave ablation of colorectal cancer liver metastasis

Ahmet Gürkan Erdemir,Sevilay Karahan,Emre Ünal,Türkmen Turan Çiftçi,Devrim Akıncı,Şuayib Yalçın,Okan Akhan 소화기인터벤션의학회 2023 International journal of gastrointestinal interven Vol.12 No.3

Background: Radiofrequency ablation (RFA) or microwave ablation (MWA) is effective for colorectal cancer liver metastases. We aimed to investigate the impact of different variables on survival. Methods: Sixty-four patients (142 lesions) who underwent thermoablation between January 2007 and January 2019 were retrospectively analyzed. The overall survival (OS) and liver progression-free survival (Li-PFS) were compared using Kaplan-Meier analysis. Univariable and multivariable Cox-regression were done to identify prognostic factors. Results: No significant difference was found between median OS (59.39 months) and Li-PFS (41.22 months) of patients who received MWA (n = 33); and median OS (61.00 months) and Li-PFS (53.43 months) of patients who received RFA (n = 31) (OS: P = 0.697; Li-PFS: P = 0.122). The median OS and Li-PFS were significantly decreased with lung metastases and K-ras mutations (P < 0.001). There was no correlation between prior systemic chemotherapy (n = 25) and both outcome parameters (OS: P = 0.613; Li-PFS: P = 0.665). No significant difference was observed in patients with lesions less than 30 mm diameter (n = 44) whether they received prior systemic chemotherapy (n = 17) or not (n = 27) (OS: P = 0.27; Li-PFS: P = 0.42). Similarly, in patients with a lesion of 3–5 cm diameter (n = 20; eight of them had prior chemotherapy), there was no correlation for both outcomes (OS: P = 0.069; Li-PFS: P = 0.71). The most important prognostic factor was concomitant lung metastases (hazard ratio = 3.689, P = 0.002). Conclusion: Concomitant lung metastasis and mutant K-ras were associated with shorter survival. Survival did not differ significantly regarding thermoablation technique or prior systemic chemotherapy. However, in the patient group with lung metastases, curative treatments had better survival than patients who received chemotherapy only. Additional therapeutic options should be considered in patients with concomitant lung metastasis.

ON SOME PROPERTIES OF THE SPACES

Aydin,Gürkanli 장전수학회 2009 Proceedings of the Jangjeon mathematical society Vol.12 No.2

For 1 ≤ p < ∞, Ap (Rn) denotes the space of all complex-valued functions in L¹ (Rn) whose Fourier transforms [수식] belong to Lp(Rn). A number of authors such as Larsen, Liu and Wang [12], Martin and Yap [14], Lai [11] worked on this space. Some generalizations to the weighted case was given by Gurkanli [7], Feichtinger and Gurkanli [4], Fischer, Gurkanli and Liu [5]. In the present paper we give another generalization of Ap (Rn) to the generalized Lebesgue space Lp(x)(Rn): We de…ne A[수식](x) (Rn) to be the space of all complex-valued functions in L[수식] (Rn) whose Fourier transforms [수식] belong to the generalized Lebesgue space Lp(x)(Rn). We endow it with a sum norm and show that A[수식](x) (Rn) is an Sw(Rn) space [2]. Further we discuss the multipliers of A[수식](x) (Rn).

Fast and effective methylene blue adsorption onto graphene oxide/amberlite nanocomposite: Evaluation and comparison of optimization techniques

Zeynep Ciğeroğlu,Gürkan Küçükyıldız,Aydın Haşimoğlu,Fulya Taktak,Nazlıcan Açıksöz 한국화학공학회 2020 Korean Journal of Chemical Engineering Vol.37 No.11

Since graphene is a miracle material of the 21st century, a considerable number of researchers have studied the oxidation of graphite to synthesize graphene oxide and its applications. In this study, polymeric resin (amberlite XAD7HP) supported graphene oxide (GO) nanocomposite was synthesized successfully. Analytical methods, namely Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and scanning electron microscopy (SEM) were utilized to characterize the new structure. Methylene blue (MB) solution was selected as a model discharged textile wastewater for adsorption application of synthesized nanocomposite. The adsorption data were modelled by response surface methodology (RSM), random forest (RF) and artificial neural networks (ANN) methods. The optimal condition parameters, which maximize the adsorption uptake capability, were determined by the genetic algorithm. Statistical errors and correlation coefficient values of each developed model were calculated independently to compare models’ performance. According to the results, the developed RF model outperformed the other models. On the other hand, the ANN model had the lowest correlation coefficient value among the models.

Quantification of void shape in cemented materials

Okan Önal,Gürkan Özden,Burak Felekoglu 사단법인 한국계산역학회 2010 Computers and Concrete, An International Journal Vol.7 No.6

A color based segmentation procedure and a modified signature technique have been applied to the detection and analyses of complicated void shapes in cemented materials. The gray-scale segmentation and available signature methods were found to be inefficient especially for the analyses of complicated void shapes. The applicability of the developed methodology has been demonstrated on artificially prepared cemented materials made of self compacted concrete material. In order to characterize the void shapes in the investigated sample images, two new shape parameters called as coefficients of inclusion and exclusion have been proposed. When compared with the traditional use of the signature method, it was found that the methodology followed herein would better characterize complicated void shapes. The methodology followed in this study may be applied to the analysis of complicated void shapes that are often encountered in other cementitious materials such as clays and rocks.