92 results on '"Karahan I"'
Search Results
2. Electrochemical synthesis of polyaniline films on zinc-cobalt alloy deposited carbon steel surface in sodium oxalate
- Author
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Ozyilmaz, A. Tuncay, Akdag, Abdurrahman, Karahan, I. Hakki, and Ozyilmaz, Gul
- Published
- 2014
- Full Text
- View/download PDF
3. The influence of polyaniline (PANI) coating on corrosion behaviour of zinc–cobalt coated carbon steel electrode
- Author
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Ozyilmaz, A. Tuncay, Akdag, Abdurrahman, Karahan, I. Hakki, and Ozyilmaz, Gul
- Published
- 2013
- Full Text
- View/download PDF
4. Giant magnetoresistance of electrodeposited Cu-Co-Ni alloy films
- Author
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Karahan, İ. H., Bakkaloğlu, Ö. F., and Bedir, M.
- Published
- 2007
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- View/download PDF
5. A study on electrodeposited NixFe1−x alloy films
- Author
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Bedir, M., Bakkaloğlu, O. F., Karahan, I. H., and Öztaş, M.
- Published
- 2006
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- View/download PDF
6. The effect of manganese chloride on gentamicin-induced nephrotoxicity in rats
- Author
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Ateşşahin, A., Karahan, I., Yilmaz, S., Çeribaşi, A. O., and Princci, I.
- Published
- 2003
- Full Text
- View/download PDF
7. Determination of the Mass Attenuation Coefficient, Effective Atomic Number and Electron Density for Nano Manganese Hydroxyapatite by using 778-1457 keV Gamma Rays
- Author
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KÖKSAL, O.k., CENGİZ, E., APAYDIN, G., TOZAR, A., and KARAHAN, İ. H.
- Subjects
Physics::Instrumentation and Detectors ,Quantitative Biology::Tissues and Organs ,Astrophysics::High Energy Astrophysical Phenomena ,Physics::Medical Physics ,Mass Attenuation Coefficient,Manganase Substituted Hydroxyapatite,Gamma Rays,Europium-152,Transmission Method - Abstract
In this study, Nano Manganesesubstituted hydroxyapatite artificial bone powders (nMnHAp) have beeninvestigated by means of mass attenuation coefficients, effective atomicnumbers and electron densities experimentally. The samples were excited withusing 778 keV, 964 keV, 1085 keV, 1111 keV, 1408 keV and 1457 keV gamma photonsfrom Europium-152 (Eu152).The gamma photons from the source werecounted by using gamma spectroscopy, a High Purity Germanium (HPGe) detector. Themass attenuation coefficients of the hydroxyapatites artificial bone powders (includinghydroxyapatite without any substituted metal and real bone powder) werecompared with each other. This study has been dealt with as aguide to medical field. Also the results have been evaluated in terms of the electrondensity and effectice atomic number.
- Published
- 2018
8. Co-existence of two different types of pancreatic neuroendocrine tumors in a patient with multiple endocrine neoplasia type-1
- Author
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Ozbas, B., Karaca, Z., Okcesiz, I., Karahan, I., Topaloglu, N., Abdulrezzak, U., Ozturk, F., and Unluhizarci, K.
- Published
- 2021
- Full Text
- View/download PDF
9. A new inflammatory marker in overweight patients: triggering receptor expressed on myeloid cells-1.
- Author
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Cifci A., Durmaz Ceylan S., Oklu K., Gungunes A., Katar D., Karahan I., Boyunaga H., and Dindar Badem N.
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MYELOID leukemia ,PHAGOCYTES ,ATHEROSCLEROSIS ,GASTROENTERITIS ,OBESITY ,INSULIN resistance ,MYELOID cells - Abstract
BACKGROUND: Triggering receptor expressed on myeloid cells 1 (TREM-1) is secreted by phagocytes in adipose tissue and it also upregulates the expression of genes involved in the inflammatory response and atherosclerotic conditions. This study was aimed to investigate the serum TREM-1 levels in overweight patients. METHODS: Twenty-eight subjects in the overweight group (OG) and 20 age-matched healthy subjects in the control group (CG) (BMI 27.6±1.2 vs 23.1±2.17 kg/m², respectively, p<0.001) were included in the study. The serum sTREM-1 level was measured by ELISA. The homeostasis model assessment score (HOMA-IR) was also calculated. RESULTS: The mean TREM-1 levels were significantly higher in OG than in CG (407.3±323.7 vs 150.3±152.7 pg/mL, respectively, p<0.001). The HOMA-IR score was also significantly higher in OG than in CG (3.42±3.63 vs 2.77±1.61, respectively). A positive correlation was detected between TREM-1 and BMI (r=0.318, p=0.028). CONCLUSIONS: This study mainly demonstrated that a high serum TREM-1 level might be an early inflammatory marker in overweight patients. We found that TREM-1 might be associated with BMI in overweight patients regardless of insulin resistance (Tab. 1, Ref. 21). Text in PDF www.elis.sk. [ABSTRACT FROM AUTHOR]
- Published
- 2020
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- View/download PDF
10. Evaluation of complete blood count parameters, cell ratios, and cell volume indices in mushroom poisonings.
- Author
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Doğan, M and Karahan, İ
- Subjects
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CELL size , *BLOOD cell count , *MEAN platelet volume , *SEPSIS , *POISONING , *LENGTH of stay in hospitals - Abstract
Objective: Mushroom poisoning is still a significant health-care problem, with the potential to affect blood parameters. The present study analyses the effect of mushroom poisoning on complete blood cell parameters, cell ratios, and cell volume indices and the effect of the mentioned parameters on prognosis/hospital length of stay. Methods: The study involved the retrospective assessment of 48 patients who became symptomatic after ingesting mushrooms. Patients who were 18 years and above and who spent at least one day in hospital were included in the study. The control group comprised individuals with similar characteristics to the patient group. The complete blood cell parameters, platelet indices (mean platelet volume, plateletcrit (PCT)), neutrophil to lymphocyte ratio (NLR), and platelet to lymphocyte ratio levels were compared between the two groups, and these ratios were analyzed for any correlation with length of hospital stay. Results: NLR was significantly higher and PCT was significantly lower in the mushroom-poisoned group, while all other parameters were similar between the groups. NLR had a positive correlation and PCT had a negative correlation with length of hospital stay. Conclusion: NLR and PCT levels can provide information about prognosis and can aid in the prediction of hospital stay in mushroom-poisoned patients. Further investigations are needed to investigate effects of intoxication on hematological system elements. [ABSTRACT FROM AUTHOR]
- Published
- 2019
- Full Text
- View/download PDF
11. Effect of solution Zn concentration on electrodeposition of CuxZn1-x alloys: materials and resistivity characterisation.
- Author
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Özdemir, R. and Karahan, İ. H.
- Subjects
ALLOY plating ,ZINC ions ,ELECTRICAL resistivity ,COBALT nickel alloys ,CYCLIC voltammetry ,MATERIALS - Abstract
Cu
x Zn1−x alloy films were electrodeposited from non-cyanide sulphate solutions. Solution zinc ion concentration was varied, while that of copper was kept constant. Cyclic voltammetry studies from solutions showed that change in zinc ion molarity causes differences in electrolyte characteristics and resulting films. Morphology, elemental composition and phase structures of electrodeposited samples were characterised using SEM, EDS and XRD, respectively. Additionally, resistivity measurements were carried out on films using the four-point probe method. Results show that change of solution zinc concentration affects morphological, elemental and structural properties of deposited films, which consequently results in different electrical resistivity behaviour. [ABSTRACT FROM AUTHOR]- Published
- 2019
- Full Text
- View/download PDF
12. Effect of current density on the corrosion protection performance of polyaniline coated AISI 4140 steel.
- Author
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Karahan, İ. H.
- Subjects
CORROSION & anti-corrosives ,ELECTROCHEMICAL analysis ,ELECTROPLATING ,CURRENT density (Electromagnetism) ,CATHODIC protection - Abstract
The present work reports on electropolymerisation of aniline onto AISI 4140 steel substrate at room temperature in oxalic acid media by the potentiodynamic electrodeposition method. The effect of coating current density on the morphology of conductive polymer films and their corrosion behaviour has been investigated. The electrolyte solution comprised 0.1 M aniline + 0.3 M oxalic acid. The effects of deposition current density changes (0.1, 0.2, 0.3, 0.4 and 0.5 mA cm
−2 ) on the films were investigated. The PANI film was characterised using cyclic voltammetry and optical microscopy; it was covered with a dark green-yellow homopolymer film of strongly adherent homogeneous characteristic. The corrosion behaviour of steel electrodes with and without polyaniline (PANI) film in 3.5 wt-% NaCl solution was investigated through anodic polarisation curves. The results indicated that the PANI coating obtained under 0.2 mA cm−2 was the most corrosion protective. [ABSTRACT FROM AUTHOR]- Published
- 2019
- Full Text
- View/download PDF
13. Electronic structure study of the bimetallic Cu1-xZnx alloy thin films.
- Author
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Ozkendir, O. Murat, Cengiz, Erhan, Mirzaei, Mahmoud, Karahan, I. Hakki, Özdemir, Rasim, and Klysubun, Wantana
- Subjects
COPPER-zinc alloys ,THIN films ,ELECTRONIC structure ,ELECTROPLATING ,X-ray absorption ,CRYSTAL structure - Abstract
A series of Zn doped copper materials were investigated upon their crystal and electronic structure with the general formula Cu1-xZnx. CuZn alloys were produced via electrodeposition method. Galvanostatic deposition was preferred for the deposition. Crystal properties of the samples were studied via X-ray diffraction (XRD) patterns and supported by the X-ray absorption fine structure spectroscopy (XAFS) data. According to the crystal structure analysis, crystal geometries of the substituted samples were mainly determined in bcc cubic. The study has revealed that, low amount of Zn substitution (0.1M) are inactive in the molecular interplays and treated as an impurity in fcc copper environment. However, higher Zn concentrations (> 0.1 M) have built bcc structure under the influence of the highly overlapped 4p levels wavefunctions of the neighbouring Cu and Zn atoms. Thus, 0.1 M zinc substitution has been determined as a threshold of the phase transition from fcc to the bcc structure. [ABSTRACT FROM AUTHOR]
- Published
- 2018
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14. Phase Formation in Electrodeposited Cu-Zn Alloy Films Produced from Ultrasonicated Solutions.
- Author
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YURDAL, K. and KARAHAN, İ. H.
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COPPER-zinc alloys , *ALLOY plating , *PHASE transitions , *CYANIDES , *METALLIC thin films , *ULTRASONICS , *SOLUTION (Chemistry) - Abstract
Thin film brass alloys were galvanostatically electrodeposited from non-cyanide citrate solutions. Aqueous sulphate solutions were used as deposition medium. It was aimed to understand the effect of ultrasonication of the solutions before electrodeposition process. Ultrasonication was not applied during deposition. This method was utilized to change solution characteristics, by applying high energy via cavitation mechanism, which would result in changes in resultant film properties. X-ray diffraction technique was used to investigate phase formation in samples. Moreover X-ray diffractograms were also used to calculate grain size values. Cu and Zn elements were codeposited successfully to form brass alloys. When phase formations in the samples were compared to each other, it was concluded that although there are small differences between X-ray diffractograms of samples, ultrasonic treatment before electrodeposition is not an effective way to alter phase characteristics of CuZn alloy samples, since all samples have shown similar X-ray diffraction graphs. Grain size is found to get smaller with presence of ultrasonication, extending ultrasonication time caused only small random changes in grain size. [ABSTRACT FROM AUTHOR]
- Published
- 2017
- Full Text
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15. A Cyclic Voltammetry Study on Electrodeposition of Cu-Zn Alloy Films: Effect of Ultrasonication Time.
- Author
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YURDAL, K. and KARAHAN, İ. H.
- Subjects
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COPPER-zinc alloys , *ALLOY plating , *CYCLIC voltammetry , *CYANIDES , *METALLIC thin films , *ULTRASONICS - Abstract
Copper zinc alloys were electrodeposited in the form of thin films. Electrodeposition process was carried out in non-cyanide aqueous medium, under constant current. Effect of pre-deposition ultrasonication of solution was investigated. In other words ultrasonic treatment was applied only before the electrodeposition. Solutions were subjected to high-energy ultrasonication for increasing times. Cyclic voltammetry was used to understand changes occurring due to duration of ultrasonication. No ultrasonication was applied during deposition. Atomic composition of resultant films were revealed by MP-AES. It was found that implementation of ultrasonic treatment before electrodeposition affects CV characteristics, when compared to non-ultrasonicated solution. Atomic composition of fabricated samples were found to be close to each other, some of them showing more deviation. [ABSTRACT FROM AUTHOR]
- Published
- 2017
- Full Text
- View/download PDF
16. Investigation of the Structural and Magnetic Properties of the Cobalt-Nickel Alloys Fabricated in Various Electrolyte Solutions.
- Author
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ÖZDEMIR, R., KORKMAZ, C. A., and KARAHAN, I. H.
- Subjects
COBALT nickel alloys ,CRYSTAL structure ,MAGNETIC properties of metals ,ELECTROLYTE solutions ,MICROFABRICATION - Abstract
Cobalt-Nickel alloys have been widely used for decoration, in magnetic recording devices and corrosion resistance applications, etc. In this study, the influences of cobalt amount in electrolyte on the magnetic and structural properties of the electrodeposited Co-Ni alloys were investigated. An electrolyte solution, consisting of cobalt sulfate, nickel sulfate, nickel chloride and boric acid, was used in electrodeposition. The electrochemical investigation of Co-Ni alloys was completed using cyclic voltammetry and galvanostatic studies. The morphological and structural analyses of the alloys were performed using inductively coupled plasma, scanning electron microscopy, X-ray diffraction and vibrating sample magnetometer techniques. The effect of cobalt concentration on the magnetic properties, phase structure and grain size of the alloys was investigated. Magnetic hysteresis results indicate that the amount of the cobalt content in the electrolyte has a strong influence on the ferromagnetic behavior of fabricated alloys. Results of the study show that changing the electrodeposition parameters, such as composition of electrolyte solution, allows to fabricate alloys with different properties. [ABSTRACT FROM AUTHOR]
- Published
- 2017
- Full Text
- View/download PDF
17. Prognostic effects of SuPAR and Neopterin Levels on Patients with Lung Cancer
- Author
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Yalcin Selim, Demir Mehmet Emin, Ozturk Reyhan, Kılınç Aytün Şadan, Suer Hatice, and Karahan Irfan
- Subjects
supar ,neopterin ,lung cancer ,Crystallography ,QD901-999 - Abstract
Background: Two unique biomarkers, soluble form of the urokinase-type plasminogen activator receptor (suPAR) and neopterin, play a crucial role in inflammatory processes. This study aimed to reveal whether it is possible to utilize these biomarkers in predicting tumor prognosis in patients with lung cancers.
- Published
- 2020
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- View/download PDF
18. Electrodeposition and Corrosive Properties of Environmental ZnFe/Polyaniline on Low Carbon Steel.
- Author
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KARAHAN, İ. H. and TILTIL, F.
- Subjects
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ELECTROPLATING , *POLYANILINES , *MILD steel , *HOMOPOLYMERIZATIONS , *X-ray diffraction - Abstract
Zinc-iron alloy plating (ZnFe) was successfully deposited on AISI 4140 steel applying cyclic voltammetry technique. Polyaniline (PANI) film was synthesized with cyclic voltammetry technique from 0.10 M aniline containing 0.30 M oxalic acid solution on zinc-iron plated carbon steel (AISI4140/ZnFe) electrode. ZnFe film was characterized by scanning electron microscopy and X-ray diffraction technique. The corrosion behaviour of zinc-iron deposited carbon steel electrodes with and without PANI film in 3.5% NaCl solution was investigated with polarization curves. Effect of pH and current density on the synthesis of the aniline was also examined. The results showed that PANI coating led to decrease of the permeability of metallic plating. The PANI homopolymer film provided an effective barrier property on zinc-iron coating and a remarkable anodic protection to substrate. ZnFe particles had more homogeneous, smooth prismatic structure. It is suggested that ZnFe/PANI deposits produced in the bath applying 0.1 mA/cm² current density probably offer bigger protection to the steel substrate. [ABSTRACT FROM AUTHOR]
- Published
- 2016
- Full Text
- View/download PDF
19. Effects of Blanking Speed on the Shear Surface of Mild Steel (St37).
- Author
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KANCA, E., EYERCİOĞLU, O., KARAHAN, I. H., GÜNEN, A., and GÖV, K.
- Subjects
SHEARING force ,STEEL corrosion ,SURFACES (Physics) ,SURFACE roughness measurement ,CORROSION & anti-corrosives - Abstract
Blanking operation is widely used to cut sheet or plates by a shearing process between punch and die. The process of shearing and the conditions of the sheared surface are influenced by the punch, the die, the speed of punching, the clearance between the punch and the die. In this study, effects of high speed blanking on surface quality and corrosion properties of mild steel St37 shear surface have been investigated. The work presented in this paper aims at evaluating the shear surface quality improvements of the St37 resulting from the use of high energy rate forging machine. The appraisal is based on criteria related to surface accuracy and corrosion resistance characterization. For this purpose, St37 mild steels were cut using three different punch speeds hydraulic presses at nearly qua-sistatic, conventional mechanical presses at low punch velocity (0.2 m/s) and high energy rate forging machine at high punch velocity (10 m/s), for different die clearances (4.5%-6% of sheet thickness). After accelerated corrosion tests, blanks were performed in conjunction with scanning electron microscopy technique to study the cutting process of the blanks at room temperature. In fact, by using high energy rate forging machine, a reduction of more than 25% of the surface roughness (R
a ) was realized and better resistance to stress corrosion cracking and pitting corrosion was noticed. It was observed that the corrosion resistance of the high energy rate forging-cut specimen was better than that of the hydraulic-cut and mechanical-cut specimens. [ABSTRACT FROM AUTHOR]- Published
- 2016
- Full Text
- View/download PDF
20. Effect of Borax Pentahydrate Addition to Acid Bath on the Microstructure and Corrosion Resistance of Zn–Co Coating.
- Author
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Karahan, İ. H.
- Subjects
- *
ALUMINUM , *ELECTROPLATING , *X-ray diffraction , *CORROSION resistance , *BORAX - Abstract
In this work, the Zn–Co coatings were synthesized on AISI 4140 steel and aluminum plates by using potentiostatic electrodeposition technique in sulphate-based acidic baths with 0, 20, 40 and 60 g l-1 of borax pentahydrate, as additive. The effect of borax pentahydrate on the microstructure of the samples was observed using scanning electron microscopy and X-ray diffractometer. The deposition process was investigated by cyclic voltammetry. The effect of borax pentahydrate on the corrosion resistance of the samples was studied by potentiodynamic polarization technique. The results have demonstrated, that the addition of borax pentahydrate was in favor of the growth of grains. The morphology of pyramidal islands on the surface was changed to a more flat structure. The results have also demonstrated that the effect of borax pentahydrate was not monotonous. With increasing concentration, the corrosion potential was at minimum and the charge transfer resistance Rt was at maximum for the sample obtained from the bath with 60 g l-1 of borax pentahydate, indicating that this sample showed the best corrosion resistance. It was found that current density first decreased and than increased, due to adsorption of a complex of borax pentahydrate and/or changes in the morphology, however, the initial deposition potential was not affected. The addition of borax pentahydrate to the bath led to formation of the best Zn–Co deposits, composed of coalesced globular fine grains, smaller than ≈2 μm in diameter. In addition, all of the studied Zn–Co deposits consisted of η phases. It is suggested that Zn–Co deposits produced in the bath containing 60 g l-1 of borax pentahydrate probably offer sacrificial protection to the steel substrate. [ABSTRACT FROM AUTHOR]
- Published
- 2015
- Full Text
- View/download PDF
21. A Comparison for Grain Size Calculation of Cu-Zn Alloys with Genetic Programming and Neural Networks.
- Author
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KARAHAN, İ. H. and ÖZDEMIR, R.
- Subjects
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ARTIFICIAL neural networks , *GENETIC programming , *ELECTROPLATING , *ALLOYS , *GRAIN size - Abstract
Neural Networks (NN) and Genetic Programming (GP) were used as a new method for formulation of grain size of electrodeposited Cu1-xZnx alloys as a function of Zinc and Copper content both electrolyte and the alloy films produced by electrodeposition technique. To predict grain size a great number of different expression models genetic programming and neural network were conducted. Each model differs from the other with their linking function, number of genes, head size, and chromosomes. To generate databases for the new grain size formulations, testing and training sets in total of 134 samples were selected at different Zn and Cu ratios of components. 6 different input parameters were selected and the output parameter was grain size of the electrodeposited Cu-Zn alloys. The testing and training sets consisted of randomly selected 106 and 28 for the proposed models. All results in the models indicated an applicable performance for predicting grain size of the alloys and found reliable. The predicted model showed that all of the input parameters effected on the resulting grain size. The NN and GEP based formulation results are compared with experimental results and found to be quite reliable with a very high correlation (R2 = 0.995 for GEP and 0.999 for NN). [ABSTRACT FROM AUTHOR]
- Published
- 2015
- Full Text
- View/download PDF
22. Corrosion inhibition performance of polymer-alloy bilayer coatings: electropolymerised polyaniline and electrodeposited ZnNi with different layer orders.
- Author
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Karahan, İ. H. and Tozar, A.
- Subjects
POLYANILINES ,POLYMER research ,CURRENT density (Electromagnetism) ,ZINC alloys ,MILD steel - Abstract
Polyaniline (PANI) conducting polymer coatings have been obtained galvanostatically with various current densities (from 0·1 to 0·4 mA cm
−2 ) and ZnNi alloy coatings have been obtained galvanostatically at 30 mA cm−2 current density. Corrosion protection performances of monolayered PANI and ZnNi alloy coatings and multi-layered ZnNi/PANI and PANI/ZnNi coatings on st-37 low carbon mild steel (MS) have been investigated by an open circuit potential method, Tafel extrapolation method and electrochemical impedance method in 3·5 wt-% NaCl solution. In addition, the surface morphology of the coatings has been characterised by using scanning electron microscopy (SEM). Synthesising PANI films between two metal layers provided better corrosion protection to the steel. MS/PANI/ZnNi layer formation exhibited the biggest corrosion protection performance among all layer formations of the films and protected MS for up to 72 h. [ABSTRACT FROM AUTHOR]- Published
- 2014
- Full Text
- View/download PDF
23. Study of effect of boric acid on Zn-Co alloy electrodeposition from acid baths and on composition, morphology and structure of deposit.
- Author
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Karahan, I H and Çetinkara, H A
- Subjects
ELECTROFORMING ,BORIC acid ,ALLOYS ,CORROSION & anti-corrosives ,MORPHOLOGY - Abstract
The effect of boric acid as additive in electrodeposition of Zn-Co alloy coatings from an acidic sulphate electrolyte containing NH 4 Cl, Na2 SO4 and citric acid Na3 C6 H5 O7 , at ambient temperature, without agitation has been investigated. The deposition process was investigated by cyclic voltammetry. It was found that the current density first decreased and then increased, due to adsorption of a boric acid complex and/or changes in the morphology, but the initial deposition potential was not affected. The addition of boric acid to the bath led to the formation of improved Zn-Co deposits, composed of coalesced globular fine grains smaller than ∼2 μm in diameter. Also, all of the Zn-Co deposits studied consisted of η phases. The Co content in the Zn-Co deposits produced in the presence of boric acid increased from 2·5 to 4·3 wt-%. It is suggested that Zn-Co deposits produced in the bath containing 60 g L-1 boric acid probably offer sacrificial protection to the steel substrate. [ABSTRACT FROM AUTHOR]- Published
- 2011
- Full Text
- View/download PDF
24. Corrosion Properties of AISI 4140 Industrial Steels Coated with Aniline in Different Storage Conditions.
- Author
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KARAHAN, İ. H.
- Subjects
- *
STEEL corrosion , *CORROSION & anti-corrosives , *ANILINE , *OXALIC acid , *ELECTRODES , *CYCLIC voltammetry - Abstract
Polyaniline (PANI) was successfully deposited by means of cyclic voltammetry technique from 0.10 M aniline containing 0.30 M oxalic acid and 1 g/l H3BO3 solution on AISI 4140 steel electrode. In this investigation nominate scan rates 25, 50, 75, and 100 mV/s have been examined. PANI film was characterized using optical microscope; it was covered with a dark green-yellow homopolymer film of strongly adherent homogeneous characteristic. The corrosion behaviour of the steel electrodes with and without PANI film in 3.5% NaCl solution was investigated through anodic polarization curves. The results indicated that PANI coating led to decrease of the permeability of metallic plating. The PANI homopolymer film provided an effective barrier property and a remarkable anodic protection to substrate. [ABSTRACT FROM AUTHOR]
- Published
- 2016
- Full Text
- View/download PDF
25. Electrodeposition and properties of Zn, Zn–Ni, Zn–Fe and Zn–Fe–Ni alloys from acidic chloride–sulphate electrolytes.
- Author
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Karahan, İ. H. and Güder, H. S.
- Subjects
ELECTROFORMING ,ELECTROLYTES ,PHASE equilibrium ,MICROALLOYING ,METALLIC composites - Abstract
Zn, Zn–Ni, Zn–Fe and Zn–Fe–Ni films have been deposited by electrochemical deposition technique onto steel plate substrates. The objective of this study was to characterise the corrosion properties of these alloys in saline solution for the application as new environmentally friendly sacrificial coatings in the protection of steel structures. The morphological and structural properties of the alloys were systematically studied using XRD and SEM techniques. Cyclic voltammetry of the individual metals was performed to help understand the electroplating process of the films. Grain sizes of the films were calculated using Scherrer's formula. Partial substitution of Zn to Fe and Ni leads to an improvement in the corrosion resistance. Compared with other zinc alloys, the Zn–Ni alloy deposit was the noblest. [ABSTRACT FROM AUTHOR]
- Published
- 2009
- Full Text
- View/download PDF
26. Electrodeposition and characterisation of Zn, Zn–Fe and Zn–Fe–Ni coatings in presence of gelatin as additive.
- Author
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Karahan, I. H., Çetinkara, H. A., and Güder, H. S.
- Subjects
CORROSION & anti-corrosives ,ALLOY plating ,ZINC ,PROTECTIVE coatings ,GELATIN ,ALLOYS ,CORROSION resistant materials - Abstract
Studies of the factors that enhance the corrosion behaviour of electrodeposited Zn, Zn–Fe and Zn-Fe-Ni coatings are highly relevant due to the considerable industrial use of these alloys as protective coatings for steel substrates. This paper reports on the corrosion behaviour and structure of Zn, Zn–Fe and Zn–Fe–Ni coatings deposited from an acid citrate solution studied in the absence and in the presence of gelatin as additive. The presence of Fe or Fe–Ni in the Zn matrix increases Zn coating corrosion resistance. The presence of gelatin in the plating bath increases the corrosion resistance of Zn, Zn–Fe and Zn–Fe–Ni coatings. [ABSTRACT FROM AUTHOR]
- Published
- 2008
- Full Text
- View/download PDF
27. Protective effect of lycopene on gentamicin-induced oxidative stress and nephrotoxicity in rats
- Author
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Karahan, İ., Ateşşahin, A., Yılmaz, S., Çeribaşı, A.O., and Sakin, F.
- Subjects
- *
LYCOPENE , *CAROTENES , *AMINOGLYCOSIDES , *ANTIBACTERIAL agents - Abstract
Abstract: A potential therapeutic approach to protect or reverse gentamicin-induced oxidative stress and nephrotoxicity would have more importance for clinical consequences. Therefore, the present study was designed to investigate the possible protective effects of lycopene against gentamicin-induced renal damage in rats. Male Sprague-Dawley rats were divided into four groups of six rats in each one; first group served as control. The other groups were treated intraperitoneally with gentamicin alone (100mgkg−1 per day) for six successive days, gentamicin for 6 days following 10 days of orally lycopene (4mgkg−1 per day) pre-treatment and 6-days of simultaneous lycopene and gentamicin. Biochemical and histopathological examinations were utilized for evaluation of the oxidative stress and renal nephrotoxicity. Creatinine, urea, Na+ and K+ levels in plasma and malondialdehyde (MDA), reduced glutathione (GSH) levels and glutathione peroxidase (GSH-Px) and catalase (CAT) activities were determined in kidney tissue. Administration of gentamicin to rats induced a marked renal failure, characterized by a significant increase in plasma creatinine and urea concentrations. The animals treated with gentamicin alone showed a significantly higher kidney MDA and lower GSH-Px and CAT activities but unaffected GSH concentrations when compared with the control group. Pre-treatment with lycopene produced amelioration in biochemical indices of nephrotoxicity in plasma. However, little changes were observed in the kidney MDA and GSH levels and GSH-Px and CAT activities when compared with the gentamicin treated group. The histological structures of the renal proximal tubules showed similar patterns. On the other hand, administration of simultaneous lycopene to rats produced amelioration in MDA and GSH levels and GSH-Px and CAT activities when compared with gentamicin group. In addition, simultaneous lycopene was found to reduce the degree of kidney tissue damage in histopathological findings. These results indicate that specially simultaneous treatment of lycopene might have produced amelioration in biochemical indices and oxidative stress parameters against gentamicin-induced nephrotoxicity, but pre-treatments with lycopene had no beneficial effects on these parameters. It was concluded that lycopene as a novel natural antioxidant might have protective effects against gentamicin-induced nephrotoxicity and oxidative stress in rats. [Copyright &y& Elsevier]
- Published
- 2005
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28. Investigation by XRF and XRD of Zn and Fe in Fex Zn1−x thin films.
- Author
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Söğüt, Ö, Bütün, H., Karahan, İ H., Tıraşoğlu, E., and Apaydın, G.
- Published
- 2008
- Full Text
- View/download PDF
29. Effect of pH treatment on K-shell x-ray intensity ratios and K-shell x-ray-production cross sections in ZnCo alloys
- Author
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Karahan, I. [Department of Physics, Faculty of Arts and Sciences, Mustafa Kemal University, TR-31040 Hatay (Turkey)]
- Published
- 2011
- Full Text
- View/download PDF
30. Effect of pH treatment on K-shell x-ray intensity ratios and K-shell x-ray-production cross sections in ZnCo alloys.
- Author
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Aylikci, N. Kup, Aylikci, V., Kahoul, A., TiraşolF;lu, E., Karahan, İ. H., and Cengiz, E.
- Subjects
- *
FLUORESCENCE , *LUMINESCENCE , *RADIOACTIVITY , *ALLOYS , *ELECTRONS - Abstract
In this study, empirical and semiempirical K-shell fluorescence yields (ωK) and Kβ/Kα intensity ratios from the available experimental data for elements with 23 ≤ Z ≤ 30 were calculated to compare them with elements in different alloys. The experimental data are fitted using the quantity [ωK(1 - ωK)]1/4 vs Z to deduce the empirical K-shell fluorescence yields and Kβ/Kα intensity ratios. The empirical and semiempirical K-shell fluorescence yield values were used to calculate the K x-ray-production cross-section values for pure Co and Zn elements. Also, σ Kα, σ Kβ production cross sections and Kβ/Kα intensity ratios of Co and Zn have been measured in pure metals and in different alloy compositions which have different pH values. The samples were excited by 59.5-keV γ rays from a 241 Am annular radioactive source. K x rays emitted by samples were counted by an Ultra-LEGe detector with a resolution of 150 eV at 5.9 keV. The effect ofpH values on alloy compositions and the effect of alloying on the fluorescence parameters of Co and Zn were investigated. The x-ray fluorescence parameters of Co and Zn in the alloying system indicate significant differences with respect to the pure metals. These differences are attributed to the reorganization of valence shell electrons and/or charge transfer phenomena. [ABSTRACT FROM AUTHOR]
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- 2011
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31. A current comprehensive role of immune-checkpoint inhibitors in resectable non-small cell lung cancer: A narrative review.
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Efil SC, Bilgin B, Ceylan F, Karakaş H, Karahan İ, Özsan SN, Kosku H, Yaman Ş, Bülent Akıncı M, Dede DŞ, Yalçın B, and Nahit Şendur MA
- Subjects
- Humans, Chemotherapy, Adjuvant methods, Antineoplastic Combined Chemotherapy Protocols therapeutic use, Clinical Trials, Phase III as Topic, Carcinoma, Non-Small-Cell Lung drug therapy, Carcinoma, Non-Small-Cell Lung immunology, Lung Neoplasms drug therapy, Immune Checkpoint Inhibitors therapeutic use, Neoadjuvant Therapy methods
- Abstract
Objective: The objective of this article is to review the efficacy, safety, and evidence for current use and potential future uses of immune-checkpoint inhibitors (ICIs) in the management of resectable non-small cell lung cancer (NSCLC)., Data Sources: A literature review was carried out through PubMed to identify completed and ongoing clinical trials evaluating the use, efficacy, and safety of ICIs in the management of resectable NSCLC., Data Summary: To date, four phase 3 trials have emerged that have changed our treatment practice concerning the utilization of ICIs during the adjuvant and neoadjuvant settings. The IMpower010 and KEYNOTE-091 trials examined the application of adjuvant atezolizumab and pembrolizumab, respectively, following surgical resection and adjuvant chemotherapy. In the CheckMate 816 trial, the combination of nivolumab and chemotherapy as a neoadjuvant therapy received approval for patients with resectable NSCLC. Also, for patients with resectable NSCLC, the use of a pembrolizumab and chemotherapy combination as a perioperative therapy received approval based on the results of the KEYNOTE-671 trial. Apart from these trials, there are numerous phase 2 and phase 3 trials, some of which have been published while others are still in progress., Conclusion: Despite the promising outcomes from these trials there remain several unanswered questions. In this review, we will assess clinical trials involving adjuvant, neoadjuvant, and perioperative ICIs, aiming to address the unresolved questions related to these therapeutic approaches., Competing Interests: Declaration of conflicting interestsThe authors declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.
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- 2024
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32. The HALP score as a prognostic factor in metastatic biliary cancer.
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Seven İ, Karahan İ, Köş FT, Bayram D, Sekmek S, and Aktürk Esen S
- Abstract
Background: Biliary tract cancers are serious diseases and new biomarkers may be useful for the optimal management and prediction of these cases. This study aimed to evaluate the prognostic significance of the hemoglobin, albumin, lymphocyte, and platelet (HALP) score, a novel composite marker, in patients with metastatic biliary tract cancer., Methods: Patients with biliary tract cancers were analyzed retrospectively. Laboratory values, patient and disease characteristics, and survival rates were evaluated. The diagnostic impact of the HALP score was assessed with regression analyses., Results: The study included 106 individuals with metastatic biliary tract cancer. Based on the median HALP score, ≥ 2.22 was considered a high score and < 2.22 was considered low. The overall average survival time was found to be 11.4 months. Patients with low HALP scores had median overall survival of 9.5 months, while those with high HALP scores had median overall survival of 15.9 months. In multivariate analysis, Eastern Cooperative Oncology Group performance status, CA19-9 level, and HALP score remained significant predictors of overall survival., Conclusion: The HALP score appears to be a useful prognostic marker in patients with metastatic biliary tract cancer., (© 2024. The Author(s), under exclusive licence to Federación de Sociedades Españolas de Oncología (FESEO).)
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- 2024
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33. Effect of HER2/CEP17 ratio on survival in metastatic HER2-positive gastric cancer, multicenter study.
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Sekmek S, Karahan I, Ucar G, Ceylan F, Bayram D, Seven I, Bölek H, Ürün Y, Yücel KB, Yazici O, Kadioglu A, Karacin C, Canaslan K, Atag E, Demirer S, Erdem GU, Ergun Y, Atak M, Koksal B, Kiran MM, Turkay DO, Civelek B, Yalcin B, and Uncu D
- Subjects
- Humans, Female, Male, Middle Aged, Adult, Aged, Aged, 80 and over, Young Adult, Prognosis, Survival Rate, Turkey epidemiology, Chromosomes, Human, Pair 17 genetics, In Situ Hybridization, Fluorescence, Stomach Neoplasms pathology, Stomach Neoplasms mortality, Stomach Neoplasms genetics, Stomach Neoplasms metabolism, Receptor, ErbB-2 metabolism
- Abstract
Aim: HER2-positive metastatic gastric cancer is still a highly fatal disease despite advances. We aimed to investigate the relationship between HER2/CEP17 ratio and survival in patients with HER2-positive metastatic gastric cancer., Methods: A total of 99 patients from 8 different centers in Turkey were included in the study. Patients with HER2-positive metastatic gastric cancer and whose HER2/CEP17 ratio was examined were included in the study. Patients were divided into two groups according to HER2/CEP17 values, and survival analysis was performed., Results: The median age was 64 (24-83) years. There were 74 (74.8%) male and 25 (25.2%) female patients. OS in the high HER2/CEP17 ratio group was 21.97 months (95% CI: 16.36-27.58), and in the low ratio group was 16.17 months (95% CI: 10.95-21.38) (p = 0.015). OS was 17.7 months (95% CI: 7.02-28.37) in the high HER2 gene copy number group and 10.13 months (5.55-14.71) in the group with low copy number (p = 0.03). PFS was 10.94 months (95% CI: 7.55-14.33) in the group with high HER2 gene copy number and 7.56 months (4.62-10.49) in the low copy number group (p = 0.06)., Conclusion: Patients with both high HER2 gene amplification and high HER2/CEP17 ratio had better OS. The PFS of the group with high HER2 gene amplification was also better. To our knowledge, this is the first study in the literature showing that the HER2/CEP17 ratio affects survival in patients with metastatic gastric cancer., (© 2024. The Author(s), under exclusive licence to Federación de Sociedades Españolas de Oncología (FESEO).)
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- 2024
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34. The Comparison of FLOT and DCF Regimens as Perioperative Treatment for Gastric Cancer.
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Uçar G, Sekmek S, Karahan İ, Ergün Y, İsak ÖA, Tunç S, Doğan M, Gürler F, Bayram D, Açıkgöz Y, Esen SA, Civelek B, Köş FT, Bal Ö, Algın E, Eren T, İmamoğlu Gİ, Urakçı Z, Yazıcı O, Özdemir N, and Uncu D
- Abstract
Introduction: Locoregional gastric cancer is a still serious problem and perioperative treatments may improve the success of management. Different regimens were examined. The present study purposed to compare the efficacy of fluorouracil-leucovorin-oxaliplatin-docetaxel (FLOT) and docetaxel-cisplatin-fluorouracil (DCF) regimens., Methods: A retrospective multicenter study assessed the patients with locoregional gastric cancer. There are 240 patients (137 DCF, 103 FLOT). Survival rates were compared., Results: Demographic features were similar between the two groups, but the time period was different. The FLOT group had 7.8% pathological complete response, while the DCF group did not. Disease-free survival was longer in the FLOT than in the DCF group (median not reached - 13.94 months, respectively). Median overall survival was similar (30.9 vs. 37.8 months), but median follow-up affected the analysis. Survival for 36 months was 63% for the FLOT group and 40% for the DCF group (log-rank; p = 0.015)., Conclusion: FLOT regimen was superior to DCF regimen for response and survival rates. DCF is a historical approach. Long-term follow-up period is needed for FLOT treatment., (© 2024 S. Karger AG, Basel.)
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- 2024
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35. Is my patient with urothelial cancer (in)eligible for platinum?
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Karahan I and Bilgin B
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- Humans, Platinum therapeutic use, Antineoplastic Combined Chemotherapy Protocols, Urinary Bladder Neoplasms drug therapy, Carcinoma, Transitional Cell drug therapy
- Abstract
Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
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- 2024
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36. Effects of Potentially Inappropriate Medications in Older Patients with Gastrointestinal System Cancer.
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Ozkan M, Karahan I, Yalcin S, and Sengul Aycicek G
- Abstract
Objective: Potentially inappropriate medications (PIM) is a crucial problem in the geriatric population. The amount of prescription and unadherence increase because of the different problems encountered in cancer patients. Our aim was to evaluate the effects of PIM in patients with gastrointestinal system cancer and to investigate its relationship with chemotherapy side effects, mortality, and progression., Methods: This retrospective cohort study assessed 154 patients with gastrointestinal system cancer. Demographics and disease features, the presence of PIM according to the "TIME-to-STOP" criteria and baseline laboratory parameters were recorded. The effects of PIM on survival and adverse treatment events were evaluated., Results: 66.9% of the cases were male and 33.1% were female. The mean age was 71.9±6.4 years. The most common side effects of chemotherapy are nausea, vomiting, kidney injury, and pain. The most frequently used prescriptions among the 98 PIMs were gliclazide, hyoscine N-butylbromide, simethicone, diphenoxylate atropine, and thiocolchicoside. PIM was detected in 68.1% of the participants. Chemotherapy side effects were more common in PIM group (p<0.001, odds ratio =5.6). PIM had no effect on mortality. Factors associated with mortality were age, stage, albumin, creatinine, operation history, and progression. A significant relationship was found between age, cancer stage, albumin, creatinine, operation history, and PIM in the regression model. There was no relationship between PIM and progression-free survival., Conclusion: Chemotherapy toxicity may increase with PIM detected on diagnosis. We suggest that PIM is an important factor in predicting the side effects of chemotherapy and minimizing the adverse effects., Competing Interests: Conflict of Interest: The authors have no conflict of interest to declare., (Copyright© 2023 The Author. Published by Galenos Publishing House on behalf of Istanbul Medeniyet University Faculty of Medicine.)
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- 2023
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37. Criteria for potentially inappropriate medications use in older adults: what about cancer patients?
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Karahan I and Bilgin B
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- Humans, Aged, Inappropriate Prescribing, Polypharmacy, Potentially Inappropriate Medication List, Neoplasms drug therapy
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- 2023
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38. COVID-19 associated thrombotic microangiopathy.
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Karabag Yilmaz E, Cebi MN, Karahan I, Saygılı S, Gulmez R, Demirgan EB, Durak C, Aygun F, Ozaltin F, Caliskan S, and Canpolat N
- Subjects
- Male, Female, Humans, Infant, Child, Preschool, SARS-CoV-2, COVID-19 complications, COVID-19 diagnosis, Thrombotic Microangiopathies diagnosis, Thrombotic Microangiopathies drug therapy, Thrombotic Microangiopathies etiology, Purpura, Thrombotic Thrombocytopenic therapy, Acute Kidney Injury diagnosis, Acute Kidney Injury drug therapy, Acute Kidney Injury etiology
- Abstract
A limited number of cases of thrombotic microangiopathy (TMA) have previously been reported in association with COVID-19. Our report describes two cases of TMA associated with COVID-19, one of which was successfully treated with eculizumab. The first case was a 23-month-old girl, and the second case was a 9-month-old boy. PCR tests for SARS-CoV-2 were positive in both cases, and laboratory results showed microangiopathic haemolytic anaemia, thrombocytopenia, and acute kidney injury. No known aetiology for TMA was found in either case. Stool tests for Shigatoxin-producing Escherichia coli were negative. Coagulation tests, ADAMTS13 activity, serum complement levels, and homocysteine levels were all within the normal range. No known genetic mutation was found, including mutations of complement, diacylglycerol kinase epsilon, and cobalamin C. In the first case, eculizumab was administered due to persistent haemolysis and prolonged anuria. In conclusion, TMA may be associated with COVID-19 infection. Treatment with eculizumab may be beneficial in selected patients because of the potential activation of the complement system., (© 2023 Asian Pacific Society of Nephrology.)
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- 2023
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39. Should clinical trials about prostate cancer assess the frailty as an endpoint?
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Karahan I and Dede DS
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- Humans, Male, Prostate-Specific Antigen, Clinical Trials as Topic, Frailty diagnosis, Prostatic Neoplasms therapy, Prostatic Neoplasms drug therapy
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- 2023
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40. The effect of metal rate on the gamma shielding parameters of hydroxyapatite at medical treatment energies.
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Koksal OK, Apaydin G, Karahan IH, and Tozar A
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- Gamma Rays, Biocompatible Materials, Durapatite, Germanium
- Abstract
The hydroxyapatite (HAp) is a kind of biomaterial which is used for bone treatment applications. We have scrutinized the gamma attenuation parameters such as such as the effective atomic number (Zeff), electron density (Nel), mass attenuation coefficient (MAC), linear attenuation coefficient (LAC), half value layer (HVL), tenth value layer (TVL) and mean free path (MFP) for only single liquid gamma source and a narrow beam geometry for the energy (medical treatment energy) ranging from 778 keV to 1408 keV (Eu-152) for the animal bone, iron, cobalt, copper, and zinc decorated Nano hydroxyapatite (nFeHAp, nCoHAp, nCuHAp, and nZnHAp) artificial bone powders. The gamma-rays were counted with using Ultra Low Energy Germanium detection system with a resolution 150 eV at 5,95 keV and a high purity germanium detector with a resolution of 1.85 keV at 1.33 MeV experimentally. The gamma ray attenuation parameters are calculated for the metal doped hydroxyapatite and compare with the animal bone. The results were compared with the output XCOM NIST data. While the mass absorption coefficient values for animal bone range from 0.08 to 0.05 at current energy levels, the values for metal-added artificial bone powders range from 0.07 to 0.05. While the linear absorption coefficient values for existing energy values for animal bone range from 0.04 to 0.02, they range from 0.03 to 0.02 for metal-added artificial bone powders. Mean free path values for real bone range from 24 to 36 at current energies, while half value layer values range from 16 to 25 and tenth value layer values range from 56 to 83. For metal-doped artificial bone powders, these parameters range from 26 to 35, 18 to 24, and 61 to 80, respectively. The results points that, the data of the gamma ray attenuation parameters are very close to the value of the animal bone due to the removal of calcium atoms from the structure when metal is added., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 Elsevier Ltd. All rights reserved.)
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- 2022
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41. Evaluation of peripheral olfactory pathways in chronic autoimmune thyroiditis.
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Inal M, Asal N, Karahan I, Güngüneş A, and Durmaz ŞA
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- Adolescent, Adult, Autoantibodies, Humans, Olfactory Pathways, Hashimoto Disease complications, Hashimoto Disease diagnostic imaging, Hypothyroidism, Thyroiditis, Autoimmune complications, Thyroiditis, Autoimmune diagnostic imaging
- Abstract
Purpose: In this study, we aimed to radiologically evaluate the olfactory bulb (OB) volume and olfactory sulcus (OS) depth of adult patients diagnosed with chronic autoimmune thyroiditis., Methods: Sixty-eight patients over 18 years of age with Hashimoto's thyroiditis and 66 healthy controls with normal thyroid function tests were included in the study. OB volume and OS depth measurements were performed using cranial magnetic resonance imaging (MRI) obtained from coronal T2-weighted images. The relationship between thyroid function tests, autoantibodies, and measurements of the OB and OS were evaluated., Results: The right and left OB volumes were significantly lower in the patients with Hashimoto's thyroiditis than in the control group (p < 0.05). No significant difference was found between the patient and control groups in terms of OS depth (p > 0.05). There were significantly negative correlations among TSH, thyroid antibodies, and the bilateral OB volume measurements. In the Bonferroni post hoc analysis, when people with euthyroid Hashimoto's thyroiditis and the control group were compared, there was no statistically significant difference between bilateral OB volumes and thyroid function tests., Conclusion: Diminished bilateral OB volumes were found in our patients with chronic autoimmune thyroiditis. Interestingly, the OB volumes were not affected in patients with euthyroid Hashimoto's thyroiditis. When a decrease in OB volume is detected on MRI, it should be kept in mind that odor dysfunction in hypothyroid patients with Hashimoto's thyroiditis may occur and patients should be clinically evaluated., (© 2022. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)
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- 2022
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42. Dietary Acid Load Associated with Hypertension and Diabetes in the Elderly.
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Omma T, Gulcelik NE, Zengin FH, Karahan I, and Culha C
- Subjects
- Acids adverse effects, Acids metabolism, Aged, Diet adverse effects, Humans, Diabetes Mellitus, Type 2, Hypertension diagnosis, Hypertension epidemiology, Hypertension etiology, Insulin Resistance
- Abstract
Background: Diet can affect the body's acid-base balance due to its content of acid or base precursors. There is conflicting evidence for the role of metabolic acidosis in the development of cardiometabolic disorders, hypertension (HT), and insulin resistance (IR)., Objective: We hypothesized that dietary acid load (DAL) is associated with adverse metabolic risk factors and aimed to investigate this in the elderly., Methods: A total of 114 elderly participants were included in the study. The participants were divided into four groups, such as HT, diabetes (DM), both HT and DM, and healthy controls. Anthropometric, biochemical, and clinical findings were recorded. Potential renal acid load (PRAL) and net endogenous acid production (NEAP) results were obtained for three days, 24-hour dietary records via a nutrient database program (BeBiS software program)., Results: The groups were matched for age, gender, and BMI. There was a statistically significant difference between the groups regarding NEAP (p =0.01) and no significant difference for PRAL ( p = 0.086). The lowest NEAP and PRAL levels were seen in the control group while the highest in the HT group. Both NEAP and PRAL were correlated with waist circumference (r = 0,325, p = 0.001; r=0,231, p =0,016, respectively)., Conclusion: Our data confirmed that subjects with HT and DM had diets with greater acid-forming potential. High NEAP may be a risk factor for chronic metabolic diseases, particularly HT. PRAL could not be shown as a significantly different marker in all participants. Dietary content has a significant contribution to the reduction of cardiovascular risk factors, such as HT, DM, and obesity., (Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.net.)
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- 2022
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43. Non-functioning adrenal incidentalomas may increase toxic metabolites.
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Karahan I, Durmaz Ceylan S, Gungunes A, Cifci A, Eker F, and Kisa U
- Subjects
- Body Mass Index, Humans, Incidental Findings, Adrenal Gland Neoplasms diagnostic imaging
- Abstract
Background: Non-functioning adrenal incidentaloma (NFAI) is a frequent diagnosis with increasing radiological tests. The emerging shreds of evidence showed that they might have negative cardiometabolic effects. The study aimed to investigate whether the toxic metabolites, asymmetric dimethylarginine (ADMA) levels, were altered in NFAI patients., Methods: We included 43 NFAI patients and 41 controls with similar ages and body mass indices in the study. We compared plasma ADMA levels of both groups and noted the radiological features of NFAIs., Results: The ADMA levels were significantly higher in NFAI patients than in the control group (307.04 ng/ml, range 81.89-577.7 ng/ml vs 192.54 ng/ml, range 70.61-440.26 ng/ml, p = 0.001). Nevertheless, we could not reach a significant correlation between ADMA levels and mass size., Conclusion: The ADMA is known as a toxin and is increased in NFAI patients. NFAIs may not be innocent and may be considered a potential risk for the body. Further investigations were needed for more explanations., (© 2021. Springer-Verlag GmbH Austria, part of Springer Nature.)
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- 2022
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44. Determination of Turkish norms of psychometric tests for diagnosing minimal hepatic encephalopathy and proposal of a high sensitive screening test battery.
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Özbaş B, Keskin O, Hecker H, Karahan I, Özbaş C, Kalkan Ç, Kartal A, Önder FO, Öncü BK, Gençdal G, Akyildiz M, Günşar F, Idilman R, Weissenborn K, Özütemiz Ö, and Yurdaydin C
- Subjects
- Humans, Liver Cirrhosis complications, Liver Cirrhosis diagnosis, Male, Psychometrics, Severity of Illness Index, Turkey epidemiology, Hepatic Encephalopathy diagnosis
- Abstract
Background: Psychometric hepatic encephalopathy score (PHES) needs local standardization., Aims: This study aimed at standardizing PHES for Turkish patients and compare them with German norms; to determine minimal hepatic encephalopathy (mHE) prevalence with two different methods [PHES battery and Critical Flicker Frequency (CFF)] and to assess whether sub-tests of the battery can be used for screening for mHE., Methods: Healthy volunteers (n = 816; 400 male) and cirrhotics (n = 124; 58 male) were included. For mHE diagnosis PHES score threshold was set at ≤ - 5 points and that of CFF at < 39 Hz. For comparing German and Turkish norms, datasets were combined. Multiple backward procedure was applied to assess effects of age, sex and education on single tests of the battery. Receiver operating characteristic (ROC) curves were created for assessing diagnostic capabilities of subtests of the battery., Results: PHES norms for Turks were developed. MHE prevalence in compensated cirrhotics was 29.8% and 27.4% with PHES and CFF tests, respectively, with low compatibility (kappa coefficient 0.389); mHE prevalence decreased to 16% when both tests were combined. Turks performed worse vs Germans in the digit symbol (DS) and serial dotting (SD) subtests but performed better in other subtests. In ROC analyzes of subtests, the combination of DS + SD tests achieved an AUROC of 0.974 versus PHES., Conclusions: Use of two methods for diagnosing mHE is important for research purposes. From a clinical perspective, sensitivity with acceptable specificity may suffice for screening instruments for mHE. Combined use of DS and SD subtests of the PHES battery appears suitable for this purpose., (© 2021. Asian Pacific Association for the Study of the Liver.)
- Published
- 2021
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45. Who Tweets About Diabetic Foot on Twitter and Which Tweets Are More Attractive?
- Author
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Karahan İ, Yürekli A, Özcömert ÖR, Oktaş B, and Çifci A
- Subjects
- Data Accuracy, Humans, Information Dissemination methods, Information Seeking Behavior, Diabetic Foot psychology, Health Education trends, Health Personnel statistics & numerical data, Social Interaction, Social Media statistics & numerical data
- Abstract
Diabetic foot is a serious problem for health care systems. Twitter can provide communication between people and it might be an informative tool for health care management. The purpose of this study is detecting the people or organizations that tweet about diabetic foot and analyze the interactions of these tweets on Twitter. All tweets containing the keyword "diabetic foot" in April 2019 were collected. The users were separated into 7 groups: patients with diabetes, health care providers, nongovernmental organizations, information sites and communication media, private companies, medical students, and others. Health care professionals and nonprofessionals were evaluated in likes, mentions, and retweets. The major group was health care providers. By 2-group comparisons of professionals and nonprofessionals, all likes, mentions, and retweets were significantly different ( P = .02, P = .04, P < .001, respectively). We concluded that the tweets of health care professionals get more interaction than others. Twitter might be a useful tool to distinguish accurate information about diabetic foot. Also, health care professionals should use for making people aware of the diabetic foot and shed light on society.
- Published
- 2020
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46. The COVID-19 anxiety of hospitalised patients in a palliative care unit.
- Author
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Karahan I
- Subjects
- Betacoronavirus, COVID-19, Humans, Pandemics, SARS-CoV-2, Turkey epidemiology, Anxiety epidemiology, Coronavirus Infections epidemiology, Coronavirus Infections psychology, Coronavirus Infections therapy, Inpatients psychology, Palliative Care psychology, Pneumonia, Viral epidemiology, Pneumonia, Viral psychology, Pneumonia, Viral therapy
- Published
- 2020
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47. Is YouTube a quality source of information on sarcopenia?
- Author
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Akyol A and Karahan İ
- Subjects
- Humans, Information Dissemination, Reproducibility of Results, Video Recording, Sarcopenia, Social Media
- Abstract
Background: While sarcopenia is a prevalent disorder that affects muscle mass and quality, patients have limited knowledge of it. On the other hand, patients often use social media to obtain health-specific information. Therefore, the aim of this study was to investigate the YouTube videos about sarcopenia in terms of the knowledge value of what they present and to identify which of them can be considered as the quality sources of such information., Methods: The descriptive study included 53 videos retrieved by searching the keywords 'sarcopenia', 'loss of muscle strength', 'sarcopenia treatment,' 'sarcopenia physiotherapy,' and'sarcopenia rehabilitation' on YouTube. The instructive characteristics of the videos were assessed with the Global Quality Scale, by which three quality groups were identified: poor-, moderate-, and high-quality videos. The DISCERN score was utilized to determine reliability. The sources of upload were identified as physicians, non-physician health personnel, health-related websites, universities and academic organizations, patients, and independent users. Finally, the lengths of videos, the number of views, likes, dislikes, and comments, and the DISCERN scores of the videos were compared using group comparisons., Results: The results suggested that there were 18 poor-quality, 16 moderate-quality, and 19 high-quality videos. Considering the sources of upload, physicians had the highest ratio in the high-quality group (83.3%). The lengths of videos and the DISCERN scores showed significant differences (p < 0.01). The numbers of views, likes, dislikes, and comments were similar in both quality and source groups., Conclusion: Most parts of the videos uploaded by physicians and academic organizations were included in the high-quality group. Overall, according to the results of the study, it can be asserted that high quality may be related to reliability. Furthermore, healthcare professionals and academics should consider using YouTube for increasing knowledge and raising awareness of patients about sarcopenia.
- Published
- 2020
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48. The role of cancer-related inflammation for prediction of poor survival in postmenopausal female patients with stage II/III colon cancer.
- Author
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Zengin M and Karahan İ
- Subjects
- Adult, Aged, Aged, 80 and over, Female, Humans, Middle Aged, Gonadal Steroid Hormones immunology, Lymphocytes immunology, Neoplasm Staging, Neutrophils immunology, Prognosis, Reproducibility of Results, Retrospective Studies, Sex Factors, Survival Analysis, Biomarkers, Tumor immunology, Colonic Neoplasms diagnosis, Colonic Neoplasms genetics, Colonic Neoplasms immunology, Colonic Neoplasms pathology, Inflammation genetics, Inflammation immunology, Postmenopause genetics, Postmenopause immunology
- Abstract
Objective: Cancer-related inflammation (CRI) is thought to be a successful predictor of prognosis in colon cancers (CC), but opinions on how to use it are highly variable. In this study, the role of CRI cells in survival for CC patients was investigated by considering gender and menopausal status., Methods: 163 stage II/III CC patients who underwent curative surgery between 1995 and 2015 were included in the study. The relationship between CRI cells was examined using a standard methodology., Results: High neutrophil-lymphocyte ratio (NLR) had a better relationship with prognostic factors, especially in postmenopausal women (gender, p = 0.037, positive surgical margin, p = 0.001; MSI, p < 0.001; Crohn's-like reaction, p = 0.001, etc). Also, the reproducibility of the study was better in postmenopausal women (intra-observer agreement = 0.72, intra-class correlation = 0.722, correlation of estimates = 0.718). In univariate analysis, 5-year survival was worse in postmenopausal women with high NLR (OS, p = 0.001; RFS, p < 0.001). In multivariate analysis, high NLR was independently a worse biomarker for OS (hazard ratio [HR], 1.29; 95% CI, 1.18-2.12; p = 0.001) and RFS (HR, 1.30; 95% CI, 1.21-2.59; p < 0.001) in postmenopausal women., Conclusions: NLR had an independent poor prognostic significance in postmenopausal female patients, and the use of a standard approach for methodology improved successful results., Competing Interests: Declaration of Competing Interest There is no conflict of interest in our study., (Copyright © 2020 Elsevier B.V. All rights reserved.)
- Published
- 2020
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49. Is C-Reactive Protein/Albumin Ratio of Advanced-Stage Non-small Cell Lung Cancer Patients Able to Predict Mortality in the Admission for Palliative Care?
- Author
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Karahan I and Yalçin S
- Abstract
Context: Lung cancer is frequent and mortal cancer. The predicting mortality may be helpful for cancer management., Aim: The purpose of the study was to evaluate the role of baseline C-reactive protein (CRP)/albumin ratio (CAR) in relation to hospital mortality, the setting of advanced stage non-small cell lung cancer (NSCLC)., Materials and Methods: The present study is a retrospective analysis and included 77 adult patients with Stage IV NSCLC who were hospitalized for supportive care. All patients are divided into two groups as survivors and nonsurvivors. CAR on the admission was compared between groups. The correlation between CAR and the death time was investigated. The cutoff level of CAR was calculated, and patients with a high level were described in two groups., Results: For all participants, the mean age was 63.0 ± 9.9 years, and the median values of CRP and albumin levels were 15.3 mg/dl (1-51.5) and 5.7 g/dl (0.02-22.7), respectively. CAR was significantly lower in the survivor group. By receiver operation curve analysis, the cutoff levels of CRP and CAR were determined as 10.8 and 3.5, respectively. The odds ratio of mortality was 3.85 (1.49-9.94 95% confidence interval [CI], P = 0.006) for higher than cutoff levels of CAR. The odds ratio was 3.38 (1.32-8.65 95% CI, P = 0.01) for higher CRP levels. There was a significant but weak negative correlation between the time of death and both CRP and CAR in the nonsurvivor group ( r = -0.46, P = 0.002; r = -0.48, P = 0.001, respectively)., Conclusion: The present study showed that CAR was significantly increased in nonsurvivors. CAR may be a cheap, easy, and effective tool for predicting the death and its time of hospitalized NSCLC patients., Competing Interests: There are no conflicts of interest., (Copyright: © 2020 Indian Journal of Palliative Care.)
- Published
- 2020
- Full Text
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50. Does Subclinical Hypothyroidism Affect Dynamic Thiol / Disulfide Homeostasis and İschemia-modified Albumin Levels in Children?
- Author
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Tursun S, Alpcan A, Ergur AT, Karahan I, Neselioglu S, and Erel O
- Subjects
- Adolescent, Biomarkers, Child, Child, Preschool, Cross-Sectional Studies, Homeostasis, Humans, Oxidative Stress, Serum Albumin, Sulfhydryl Compounds, Disulfides, Hypothyroidism diagnosis, Hypothyroidism metabolism, Hypothyroidism physiopathology, Serum Albumin, Human
- Abstract
Objective: To determine the effects of subclinical hypothyroidism on oxidative stress in children., Study Design: A cross-sectional study., Place and Duration of Study: Department of Paediatrics, Paediatric Endocrinology, and General Outpatient Clinics, Kirikkale University, School of Medicine, from May 2017 to October 2018., Methodology: This study included 92 subjects aged between 2 and 18 years. The subjects were divided into two groups. Forty-seven children with subclinical hypothyroidism and 45 healthy controls were evaluated. In order to evaluate oxidative damage, native thiol, total thiol, disulfides, their ratios, and ischemia-modified albumin (IMA) levels were compared between the two groups. The relationship between TSH and IMA levels was assessed., Results: Age and gender were not significantly different in the two groups. Native thiol, total thiol, disulfides and their ratios were similar in the two groups. Ischemia-modified albumin levels were significantly higher in the patient group than the controls (p<0.001). There was no correlation between TSH and IMA levels in the patient group (r=0.069 p=0.645)., Conclusion: Subclinical hypothyroidism may be related to the impairment of IMA, and have a neutral effect on thiol/disulfide balance. Further research is needed to explain the effects of oxidative stress in subclinical hypothyroidism. Key Words: Subclinical hypothyroidism, Childhood, Oxidative stress.
- Published
- 2020
- Full Text
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