The Restorative Effect of Gallic Acid on the Experimental Sciatic Nerve Damage Model

Gurkan, Gokhan,Erdogan, Mumin Alper,Yigitturk, Gurkan,Erbas, Oytun The Korean Neurosurgical Society 2021 Journal of Korean neurosurgical society Vol.64 No.6

Objective : Peripheral nerve injuries occur mostly as a result of mechanical trauma. Due to the microvascular deterioration in peripheral nerve damage, it becomes challenging to remove free oxygen radicals. Gallic acid is a powerful antioxidant with anti-inflammatory effects and a free radical scavenger. The purpose of the study is to show that gallic acid contributes to the restorative effect in mechanical nerve damage, considering its antioxidant and anti-inflammatory effects. Methods : Thirty male Sprague Dawley albino mature rats were included in the study. Ten of them constituted the control group, 10 out of 20 rats for which sciatic nerve damage was caused, constituted the saline group, and 10 formed the gallic acid group. Post-treatment motor functions, histological, immunohistochemical, and biochemical parameters of the rats were evaluated. Results : Compared to the surgery+saline group, lower compound muscle action potential (CMAP) latency, higher CMAP amplitude, and higher inclined plane test values were found in the surgery+gallic acid group. Similarly, a higher nerve growth factor (NGF) percentage, a higher number of axons, and a lower percentage of fibrosis scores were observed in the surgery+gallic acid group. Finally, lower tissue malondialdehyde (MDA) and higher heat shock protein-70 (HSP-70) values were determined in the surgery+gallic acid group. Conclusion : Gallic acid positively affects peripheral nerve injury healing due to its anti-inflammatory and antioxidant effects. It has been thought that gallic acid can be used as a supportive treatment in peripheral nerve damage.

Catalytic Spectrophotometry for the Determination of Manganese at Trace Levels by a Novel Indicator Reaction

Gurkan, Ramazan,Caylak, Osman Korean Chemical Society 2010 대한화학회지 Vol.54 No.5

새로운 동적 분광 광도 측정법은 천연의 물 샘플에서 망간(II)의 측정을 위해 개발되었다. 그 방법은 620 nm에서 활성화제로서 nitrilotriacetic acid (NTA)를 사용하면서 $KIO_4$에 의한 갈로시아닌(Gallocyanin)의 산화와 함께 망간(II)의 촉매 효과에 기초했다. 최적조건은 갈로시아닌(Gallocyanin) $4.00{\times}1^{-5}\;M$, $KIO_4$ $1.00{\times}10^{-4}\;M$, NTA $1.00{\times}10^{-4}\;M$, pH = 3.50인 0.1 M HAc/NaAc 완충용액, 5분의 반응시간 그리고 $30^{\circ}C$의 온도에서 얻어졌다. 최적조건 하에서 제안된 방법은 $0.1\;-\;4.0\;ng\;mL^{-1}$의 범위에서 망간(II)의 측정을 허용했고 $0.025\;ng\;mL^{-1}$이하의 검출한계를 가지고 있다. 표준 망간(II) 용액을 측정하는 것에서 회수율은 98.5 - 102% 범위에 있다. 그리고 상대표준편차(RSD)는 0.76 - 1.25%의 범위에 있다. 새롭게 개발된 동적 방법은 약간의 주위의 물과 만족할 만한 결과를 갖는 JAC-0031의 공인된 표준 기준 강물 샘플 둘 다에서 망간(II)의 측정에 성공적으로 응용되었다. 또한, 얼마 안 되는 양이온과 음이온은 망간(II)의 측정을 방해한다. 다른 촉매-동적 방법과 기기적 방법과 비교했을 때, 제안된 동적 방법은 상당히 좋은 선택성과 감도, 낮은 가격, 저렴함, 낮은 검출한계와 신속함을 보인다. 상대적으로 낮은 염분을 갖는 진짜 물 샘플과 병으로 된 마시는 물, 차갑고 뜨거운 용천수, 호수, 강물 샘플 같은 복잡한 모체들에 적용하는 것은 쉽고 성공적으로 적용될 수 있다. A new kinetic spectrophotometric method is developed for the measurement of Mn(II) in natural water samples. The method is based on the catalytic effect of Mn(II) with the oxidation of Gallocyanin by $KIO_4$ using nitrilotriacetic acid (NTA) as an activation reagent at 620 nm. The optimum conditions obtained are $4.00{\times}1^{-5}\;M$ Gallocyanin, $KIO_4$, $1.00{\times}10^{-4}\;M$ NTA, 0.1 M HAc/NaAc buffer of pH = 3.50, the reaction time of 5 min and the temperature of $30^{\circ}C$. Under the optimum conditions, the proposed method allows the measurement of Mn(II) in a range of $0.1\;-\;4.0\;ng\;mL^{-1}$ and with a detection limit of down to $0.025\;ng\;mL^{-1}$. The recovery efficiency in measuring the standard Mn(II) solution is in a range of 98.5 - 102%, and the RSD is in a range of 0.76 - 1.25%. The newly developed kinetic method has been successfully applied to the measurement of Mn(II) in both some environmental water samples and certified standard reference river water sample, JAC-0031 with satisfying results. Moreover, few cations and anions interfere with the measurement of Mn(II). Compared with the other catalytic-kinetic methods and instrumental methods, the proposed kinetic method shows fairly good selectivity and sensitivity, low cost, cheapness, low detection limit and rapidity. It can easily and successfully be applied to the real water samples with relatively low salt content and complex matrices such as bottled drinking water, cold and hot spring waters, lake water, river water samples.

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

Gurkan, Ramazan,Ulusoy, Halil Ibrahim Korean Chemical Society 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, $Br_2$ or $Cl_2$ plus $Br_2$ 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 ${\mu}gL^{-1}$ of Se(IV) for the fixed time method at $25^{\circ}C$. The detection limit based on statistical $3S_{blank}$/m-criterion was 0.215 ${\mu}gL^{-1}$ for 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 ${\mu}gL^{-1}$ of 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).

Expansive Networks: Exploiting Spectrum Sharing for Capacity Boost and 6G Vision

Gurkan Gur 한국통신학회 2020 Journal of communications and networks Vol.22 No.6

Adaptive capacity with cost-efficient resource provisioning is a crucial capability for future 6G networks. In this work, weconceptualize “expansive networks” which refers to a networkingparadigm where networks should be able to extend their resourcebase by opportunistic but self-controlled expansive actions. To thisend, we elaborate on a key aspect of an expansive network as aconcrete example: Spectrum resource at the PHY layer. Evidently,future wireless networks need to provide efficient mechanisms tocoexist in the licensed and unlicensed bands and operate in expansive mode. In this work, we first describe spectrum sharing issuesand possibilities in 6G networks for expansive networks. We thenpresent security implications of expansive networks, an importantconcern due to more open and coupled systems in expansive networks. We also discuss two key enablers, namely distributed ledgertechnology (DLT) and network intelligence via machine learning,which are promising to realize expansive networks for the spectrum sharing aspect.

Synthesis and anticancer effects of some novel 2-(4- phenoxyphenyl)-1H-benzimidazole derivatives on K562 cell line

A. Selen Gurkan-Alp,Hakan Go¨ker,Mehmet Alp,Tulin Ozkan,Asuman Sunguroglu 대한약학회 2015 Archives of Pharmacal Research Vol.38 No.5

A series of novel 2-(4-phenoxyphenyl)-1Hbenzimidazolederivatives was synthesized and testedin vitro on human chronic myelogenous leukemia (CML)cell line K562. Benzimidazoles containing 5-amidino (10),5-N-isopropylamidino (11), 5-bromo (13), and 5,6-dimethyl(14) derivatives exhibited remarkable cytotoxicactivity. The quantitative analysis of apoptosis by flowcytometrydemonstrated that the percentages of early andlate apoptotic K562 cells treated with these compoundswere significantly higher than cells without treatment. Wealso investigated the effects of these compounds on theexpression of apoptosis-related genes BAX, BCL-2, BADand BIM. Treatment of K562 cells wih compounds 10–14significantly increased the expression levels of the proapoptoticgenes BAX, BAD and BIM, whereas compound20 increased BAX and BAD.

Effect of layer thickness and print orientation on strength of 3D printed and adhesively bonded single lap joints

Volkan Kovan,Gurkan Altan,Eyup Sabri Topal 대한기계학회 2017 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.31 No.5

Three-dimensional printing is the common name given to various techniques used to manufacture different objects. Fused deposition technique is a commonly used additive manufacturing technology in prototyping and production. Fused deposition modelling systems are limited in terms of shape and size of parts. Printing parts with less support material, for parts too large to print in a single operation or for parts with fine details, sectioning and adhesively bonding is the solution for manufacturing. According to adhesion theory, the strength of adhesively bonding between three-dimensional printed parts is affected by surface roughness. Effects of layer thickness and print orientation on adhesion strength of parts manufactured with three-dimensional printing were experimentally studied. As a result of the study, it was found that the edgewise orientation had the highest bonding strength in lower layer thicknesses, while flatwise orientation had the highest bonding strength in higher layer thicknesses.

Modeling and Implications of Airport Ground Egress Mode Choice

Ilgin Gokasar,Gurkan Gunay 대한토목학회 2021 KSCE JOURNAL OF CIVIL ENGINEERING Vol.25 No.2

Mode choice of airport ground access has been covered by several studies, but there is a lack of research in the case of airport ground egress; that is, mode choices of inbound passengers for ground trips from the airport to the city center. This study aimed to cover this gap by modeling the ground egress mode choice of passengers, employing mixed logit and comparing it with the multinomial logit model. The data for this research was collected at Istanbul’s Sabiha Gokcen International Airport (SAW) in 2015. Analyses included six modes, namely automobile, pick-up, public transit, taxi, shuttle and public transit (SP), and shuttle and taxi (ST). An important outcome was that a mixed logit model with error components outperformed the multinomial logit model. Results showed that significant variables affecting the ground egress mode choice included the income of the passenger, the cost of a ground trip from the airport, auto ownership status, number of luggage and trip purpose. Passengers are less constrained by ground travel time in their airport egress trips than in their airport access trips. By this, a significant finding was that prioritizing egress trip cost over travel time affected the mode choice.

Growing Hemorrhagic Choroidal Fissure Cyst

Karatas, Ayse,Gelal, Fazil,Gurkan, Gokhan,Feran, Hamit The Korean Neurosurgical Society 2016 Journal of Korean neurosurgical society Vol.59 No.2

Choroidal fissure cysts are often incidentally discovered. They are usually asymptomatic. The authors report a case of growing and hemorrhagic choroidal fissure cyst which was treated surgically. A 22-year-old female presented with headache. Cranial MRI showed a left-sided choroidal fissure cyst. Follow-up MRI showed that the size of the cyst had increased gradually. Twenty months later, the patient was admitted to our emergency department with severe headache. MRI and CT showed an intracystic hematoma. Although such cysts usually have a benign course without symptoms and progression, they may rarely present with intracystic hemorrhage, enlargement of the cyst and increasing symptomatology.

A deep learning approach to permanent tooth germ detection on pediatric panoramic radiographs

Kaya Emine,Gunec Huseyin Gurkan,Aydin Kader Cesur,Urkmez Elif Seyda,Duranay Recep,Ates Hasan Fehmi 대한영상치의학회 2022 Imaging Science in Dentistry Vol.52 No.3

Purpose: The aim of this study was to assess the performance of a deep learning system for permanent tooth germ detection on pediatric panoramic radiographs. Materials and Methods: In total, 4518 anonymized panoramic radiographs of children between 5 and 13 years of age were collected. YOLOv4, a convolutional neural network (CNN)-based object detection model, was used to automatically detect permanent tooth germs. Panoramic images of children processed in LabelImg were trained and tested in the YOLOv4 algorithm. True-positive, false-positive, and false-negative rates were calculated. A confusion matrix was used to evaluate the performance of the model. Results: The YOLOv4 model, which detected permanent tooth germs on pediatric panoramic radiographs, provided an average precision value of 94.16% and an F1 value of 0.90, indicating a high level of significance. The average YOLOv4 inference time was 90 ms. Conclusion: The detection of permanent tooth germs on pediatric panoramic X-rays using a deep learning-based approach may facilitate the early diagnosis of tooth deficiency or supernumerary teeth and help dental practitioners find more accurate treatment options while saving time and effort.

A deep learning approach to permanent tooth germ detection on pediatric panoramic radiographs

Kaya, Emine,Gunec, Huseyin Gurkan,Aydin, Kader Cesur,Urkmez, Elif Seyda,Duranay, Recep,Ates, Hasan Fehmi Korean Academy of Oral and Maxillofacial Radiology 2022 Imaging Science in Dentistry Vol.52 No.-

Purpose: The aim of this study was to assess the performance of a deep learning system for permanent tooth germ detection on pediatric panoramic radiographs. Materials and Methods: In total, 4518 anonymized panoramic radiographs of children between 5 and 13 years of age were collected. YOLOv4, a convolutional neural network (CNN)-based object detection model, was used to automatically detect permanent tooth germs. Panoramic images of children processed in LabelImg were trained and tested in the YOLOv4 algorithm. True-positive, false-positive, and false-negative rates were calculated. A confusion matrix was used to evaluate the performance of the model. Results: The YOLOv4 model, which detected permanent tooth germs on pediatric panoramic radiographs, provided an average precision value of 94.16% and an F1 value of 0.90, indicating a high level of significance. The average YOLOv4 inference time was 90 ms. Conclusion: The detection of permanent tooth germs on pediatric panoramic X-rays using a deep learning-based approach may facilitate the early diagnosis of tooth deficiency or supernumerary teeth and help dental practitioners find more accurate treatment options while saving time and effort