Browsing by Author "Çelik A."
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Item Pb(II) and Cd(II) removal from aqueous solutions by olive cake(2006) Doyurum S.; Çelik A.The removal of heavy metals from wastewater using olive cake as an adsorbent was investigated. The effect of the contact time, pH, temperature, and concentration of adsorbate on adsorption performance of olive cake for Pb(II) and Cd(II) ions were examined by batch method. Adsorption of Pb(II) and Cd(II) in aqueous solution onto olive cake was studied in single component. After establishing the optimum conditions, elution of these ions from the adsorbent surface was also examined. The optimum sorption conditions were determined for two elements. Maximum desorption of the Pb(II) and Cd(II) ions were found to be 95.92 and 53.97% by 0.5 M HNO3 and 0.2 M HCl, respectively. The morphological analysis of the olive cake was performed by the scanning electron microscopy (SEM). © 2006 Elsevier B.V. All rights reserved.Item Fluoride release from esthetic restorative materials with and without adhesive(2006) Pamir T.; Tezel H.; Özata F.; Çelik A.Objective: The purpose of this in vitro study was to compare the effect of surface coating containing fluoride on patterns and amounts of fluoride release from 5 esthetic restorative materials. Method and materials: Twelve cylinders of each material were prepared in a plexiglass mold. The experimental groups (n = 6) were coated with 1 layer of fluoridated adhesive resin, Prompt L-Pop, while the control groups (n = 6) remained uncoated. Fluoride release into deionized water was measured on days 1, 2, 3, 7, 14, 21, and 28 using an ion analyzer. Results were evaluated statistically using repeated measure analysis of variance and Duncan test. Results: In the uncoated materials, the highest fluoride-releasing material was a resin composite Ariston pHc (140.468 ± 9.80) followed by Photac-fil (101.200 ± 5.56), Ketac-fil (91.098 ± 4.69), Hytac Aplitip (5.122 ± 1.00), and Ecusit (0.310 ± 0.18). Material-coating interaction was found to be significant, but the effect of surface coating was different for each material. Among the coated materials, conventional glass-ionomer cement Ketac-fil released the highest amount of fluoride (93.326 ± 10.86), followed by Photac-fil (83.666 ± 4.72), Ariston pHc (53.862 ± 7.90), Hytac Aplitip (14.634 ± 2.35), and Ecusit (1.355 ± 0.29). Conclusion: Application of fluoridated adhesive affected fluoride release from each material in varying magnitudes.Item Adsorption of Cd(II) ions from aqueous solutions using activated carbon prepared from olive stone by ZnCl2 activation(2008) Kula I.; Uǧurlu M.; Karaoǧlu H.; Çelik A.This study is aimed to remove Cd(II) ions from aqueous solutions by adsorption. As adsorbent, activated carbon prepared from olive stone, an agricultural solid by-product was used. Different activating agent (ZnCl2) amounts and adsorbent particle size were studied to optimize adsorbent surface area. The adsorption experiments were conducted at different parameters such as, adsorbent dose, temperature, equilibrium time and pH. According to the experiments results, the equilibrium time, optimum pH, adsorbent dosage were found 60 min, pH > 6 and 1.0 g/50 ml respectively. The kinetic data supports pseudo-second order model and intra-particle model but shows very poor fit for pseudo-first order model. Adsorption isotherms were obtained from three different temperatures. These adsorption data were fitted with the Langmuir and Freundlich isotherms. In addition, the thermodynamic parameters, standard free energy (ΔG0), standard enthalpy (ΔH0), standard entropy (ΔS0) of the adsorption process were calculated. To reveal the adsorptive characteristics of the produced active carbon, BET surface area measurements were made. Structural analysis was performed using SEM-EDS. The resulting activated carbons with 20% ZnCl2 solution was the best sample of the produced activated carbons from olive stone with the specific surface area of 790.25 m2 g-1. The results show that the produced activated carbon from olive stone is an alternative low-cost adsorbent for removing Cd(II). © 2007 Elsevier Ltd. All rights reserved.Item Activation of peripheral opioid receptors has no effect on heart rate variability(2008) Ellidokuz E.; Kaya D.; Uslan I.; Çelik A.; Esen A.M.; Barutça I.Opioid receptors involved in regulating the motility of the gastrointestinal tract have been localized in both contractile and neuronal tissues. Trimebutine, a peripheral opioid receptor agonist, modulates gastrointestinal motor activity in both directions and also may act on cardiac tissue. This study investigated the effects of trimebutine in clinical doses on cardiac autonomic functions with heart rate variability. The effect of trimebutine on cardiac autonomic outflows was evaluated in 11 healthy subjects. Trimebutine (200 mg) or placebo was administered orally at random in a double-blind, cross-over manner. Continuous electrocardiography recordings were obtained before and after drug administration during three states: rest, controlled breathing, and a hand grip exercise. Heart rate variability analysis showed that there was no significant difference between subjects administered with placebo or trimebutine throughout rest, controlled breathing, or the hand grip exercise. We concluded that trimebutine, in clinical doses, has no significant effect on cardiac autonomic functions. © 2008 Springer.Item Some heavy metal determination by ICP-OES in human scalp hair (In three different regions of Manisa); [İnsan saçında bulunan (Manisa İlinin üç farklı yerleşim bölgesinde) Bazı aǧir metallerin ICP-OES yöntemi ile tayini](Ekoloji, 2009) Çelik A.; Abali Y.; Edgünlü G.; Uzunoǧlu S.; Tirtom V.N.The aim of this study was to determine the levels of As, Cd, Mn, Cr, Fe, Pb, Hg, Zn and Se in hair samples collected from the nape of the neck of voluntary people living or working in the industrial region, city center and countryside of Manisa province. The concentrations of As, Cd, Mn, Cr, Fe, Pb, Se, Zn were determined by ICP-OES. The measured values of trace elements in human hair samples were compatible to the reference values given in the literature. The measured values of As, Hg, Cr, Cd, Se and Pb were found below the detection limit of the method. Zn, Mn and Fe were statistically analysed and evaluated. When the Fe and Mn values of the hair samples collected from the industrial region were compared with the data from both the city center and countryside (ANOVA), the differences were meaningful and significant, but the differences for Zn between the industrial region, city center and countryside were found to be insignificant.Item The prevalence of microalbuminuria and relevant cardiovascular risk factors in Turkish hypertensive patients(2011) Kozan Ö.; Özcan E.E.; Sancaktar O.; Kabakci G.; Sözcüer A.H.; Kerpeten A.; Delice A.; Içli A.; Sökmen A.; Gürlek A.; Abaci A.; Bayram A.; Köşüş A.; Çamsari A.; Sakalli A.; Sert A.; Temizhan A.; Yilmaz A.; Daver A.; Aydinlar A.; Ergin A.; Kiliçoǧlu A.E.; Birdane A.; Aribaş A.; Lazoǧlu A.; Özdemir A.; Fiskeci A.; Çelik A.; Bitigen A.; Keskin A.; Yavuz A.; Akyüz A.; Karanfil A.; Ünsal A.; Sinci A.; Gülmez A.U.; Irmak A.; Vural A.; Güven A.; Ilerigelen B.; Erol B.; Polat B.; Tosun B.; Aǧçal C.; Genç C.; Kirdar C.; Rezzagil C.; Köz C.; Nazli C.; Ceyhan C.; Örem C.; Uyan C.; Türkoǧlu C.; Gaffari D.; Aytekin D.; Ural D.; Yeşilbursa D.; Aras D.; Semiz E.; Koçak E.; Atalar E.; Varol E.; Onrat E.; Şensoy E.; Acartürk E.; Akarca E.; Aygün E.; Ertaş F.S.; Koca F.; Özmen F.; Ulusoy F.V.; Özerkan F.; Inceer F.K.; Dönmez G.; Topkara G.; Daş G.; Bozkurt H.; Kültürsay H.; Tikiz H.; Akgöz H.; Kaymak H.; Öney H.; Yeǧin H.; Boǧa H.; Gök H.; Vural H.; Atasever H.; Arinç H.; Bozdemir H.; Gündüz H.; Tunar H.; Atmaca H.; Doǧru I.; Özdoǧru I.; Susal I.; Kurt I.T.; Dinçer I.; Biyik I.; Tandoǧan I.; Jordan J.; Kulan K.; Şahna K.; Öztaş K.; Dönmez K.; Övünç K.; Kaya K.; Aytemir K.; Özdemir K.; Tigen K.; Saraç L.; Sirkeci M.T.; Çakmak M.; Şahin M.; Kutlu M.; Bilge M.; Bostan M.; Melek M.; Sunay M.Ö.; Şeker M.; Güçel M.Ş.; Yazici M.; Kayikçioǧlu M.; Öç M.; Gürsürer M.; Daǧalp M.; Bilaloǧlu M.; Yalçin M.; Şerifi M.; Gökçe M.; Kiliçkap M.; Polat M.; Şan M.; Tahtasiz M.; Yilmaz M.; Etemoǧlu M.; Coşkun N.; Aran N.S.; Ata N.; Sönmez N.; Çam N.; Koylan N.; Özer N.; Keser N.; Döven O.; Tartanoǧlu O.; Ergene O.; Elönü O.H.; Onbaşili O.A.; Özbek Ö.; Pinar P.; Akdemir R.; Kargin R.; Topsakal R.; Yoldaş R.; Uçar R.; Ateşal S.; Toktaş S.; Cinsoy S.; Güleç S.; Aytekin S.; Çolak S.; Mecit S.; Sakalli S.; Sevimli S.; Topaloǧlu S.; Aydoǧdu S.; Turan S.C.; Kahraman S.; Yorganci S.; Coşkun Ş.; Ünal Ş.; Durmaz T.; Ulusoy T.; Keleş T.; Kirat T.; Gündoǧdu T.T.; Peker T.; Sümerkan U.; Aytekin V.; Koca V.; Çam V.; Gökçe V.; Gürlertop Y.; Balbay Y.; Çavuşoǧlu Y.; Erzurum Y.; Selçoki Y.; Yakar Y.; Işilak Z.; Tosun Z.; Kaplan Z.; Tartan Z.Objectives: A growing body of data illustrates the importance of microalbuminuria (MAU) as a strong predictor of cardiovascular risk in the hypertensive population. The present study was designed to define the prevalence of MAU and associated cardiovascular risk factors among Turkish hypertensive outpatients. Study design: Representing the Turkish arm of the multinational i-SEARCH study involving 1,750 sites in 26 countries around the world, a total of 1,926 hypertensive patients from different centers were included in this observational and cross-sectional survey study. Patients with reasons for a false-positive MAU test were excluded. The prevalence of MAU was assessed using a dipstick test, and patients were inquired about comorbidities, comedication, and known cardiovascular risk factors. Results: The overall prevalence of MAU was 64.7% and there was no difference between genders. Most of the patients (82.5%) had uncontrolled hypertension, 35.6% had dyslipidemia, and 35.5% had diabetes, predominantly type 2. Almost one-third of the patients (26.4%) had at least one cardiovascular-related comorbidity, with 20.3% having documented coronary artery disease (CAD). Almost all patients (96.8%) had one or more risk factors for cardiovascular disease in addition to hypertension, including family history of myocardial infarction or CAD, diabetes, dyslipidemia, lack of physical exercise, and smoking. A trend towards higher MAU values in the presence of CAD was determined. Conclusion: Microalbuminuria tests should be routinely used as a screening and monitoring tool for the assessment of subsequent cardiovascular morbidity and mortality among hypertensive patients. © 2011 Turkish Society of Cardiology.Item Investigation of some pollution parameters in water and sediment samples collected from the lower gediz river basin; [Gediz nehri aşaǧi̇ gediz havzasi̇'ndan ali̇nan su ve sediment örneklerinde bazi̇ kirlilik parametrelerinin i̇ncelenmesi](2011) Öner O.; Çelik A.The River Gediz, is the second greatest river of Aegean Region, is under threat of pollution caused by institutions of region, domestic waste, agricultural chemicals and artificial fertilizers. All kinds of substances which are above standardized limit values for water can make pollution. These pollutant levels could determine water usage aims. Heavy metals in trace level are the most hazardous of these matters. In our study, the physical and chemical parameters of water and the level of heavy metal concentration in water and sediment samples are analyzed in five different stations of Gediz River. The average level of some parameters are; BOD: 67.7 mg/L, COD: 88.7 mg/L, pH: 7.6, turbidity: 440 mg/L SiO2. In water samples, the metals in high level are; Pb: 27.0±%0.8 μg/L at Nif River, Cr: 48.9±%0.9 μg/L at Muradiye Bridge, Cd: 12.1±%0.6 μg/L at Istanbul Bridge, Cu: 90.2±%0.4 μg/L at Muradiye Bridge, Ni: 309.8±%0.7 μg/L, Fe: 914.1±%0.3 μg/L, Zn: 208.3±%0.5 μg/L in Karaçay. The quality of water is at the level of four, according to Water Pollution Control Regulations. The sediment and soil samples taken from different station were also compared. It is seen that, the organic matter which is accumulated at the bottom of the river, increase the concentration of the metals.Item Arsenic removal from aqueous system using natural and modified (Kula ebonite and zeolite) adsorbents(2012) Gülbaş G.; Tirtom V.N.; Çelik A.; Dost K.Natural adsorbents (Kula ebonite, zeolite and zeolite treated with Al 2(SO4)3; Al2(SO4) 3+NaOH; FeCl3 and FeCl3+NaOH) were prepared and employed by means of batch method for selective adsorption and removal of arsenic from aqueous system. The influences of different parameters such as, contact time, pH, temperature, and concentration of adsorbate on adsorption performance of zeolite and zeolite treated with FeCl3 and FeCl 3+NaOH were studied in order to optimize the adsorption conditions. Batch adsorption studies have shown that removal capacity of zeolite from aqueous solutions can be increased by FeCl3 and FeCl3+NaOH treatment. The maximum adsorption capacities were 1.99 and 3.43 mg g -1 of zeolite which was treated with FeCl3 and FeCl 3+NaOH for arsenic, respectively. The adsorption data obtained follows a first-order rate expression and fits the Langmuir isotherm that has been used to obtain thethermodynamic parameters. In addition, the thermodynamic parameters, standard free energy (ΔG°), standard enthalpy (ΔH°), standard entropy (ΔS°) of the adsorption process were calculated. It was found that the adsorption of arsenic on zeolite was exothermic. © 2012 American Institute of Chemical Engineers.Item Comparative adsorption of Ni(II) and Cd(II) ions on epichlorohydrin crosslinked chitosan-clay composite beads in aqueous solution(2012) Tirtom V.N.; Dinçer A.; Becerik S.; Aydemir T.; Çelik A.Removal of Ni(II) and Cd(II) by adsorption on epichlorohydrin crosslinked chitosan-clay composite beads was examined in solutions representative of contaminated solutions containing heavy metals. Several important parameters influencing the adsorption of Ni(II) and Cd(II) ions such as contact time, pH, temperature and effect of metal concentration were investigated systematically by batch experiments. Langmuir and Freundlich adsorption models were used to describe adsorption isotherms and constants. The obtained results showed that the equilibrium adsorption behavior of Ni (II) and Cd (II) on epichlorohydrin crosslinked chitosan-clay composite beads could be applied to Langmuir and Freundlich models respectively. Maximum adsorption capacities for Ni(II) and Cd(II) ions were found as 32.36mgg-1 and 72.31mgg-1 respectively. The recovery of the metal ions after adsorption and the regeneration of the adsorbent was carried out by treatment of the loaded beads with either 0.1M HNO3, or 0.01M EDTA. The adsorbents were characterized by FTIR, SEM and TGA analysis. © 2012 Elsevier B.V.Item Removal of lead (II) ions from aqueous solution by using crosslinked chitosan-clay beads(Elsevier B.V., 2012) Tirtom V.N.; Dinçer A.; Becerik S.; Aydemir T.; Çelik A.Faculty of Arts and Sciences, Department of Chemistry, Celal Bayar University, 45140, Manisa Turkey Tel. +90 2362412151; Fax: +90 2362412128, +90 2362412158;A simple and effective biodegradable material known as chitosan-clay composite beads wereprepared to remove Pb(II) ions from aqueous solution. For this purpose, various importantparameters such as contact time, pH and temperature were examined on the adsorption ofPb(II) ions onto crosslinked chitosan-clay composite beads. Maximum adsorption capacity ofPb(II) was observed at pH 4.5 and 25°C and calculated as 7.93 mg/g according to Langmuirisotherm model. Thermodynamic parameters namely ΔG°, ΔH° and ΔS° of the Pb(II) adsorptionprocess have been calculated as 7.889 kJ/mol, -15.131 kJ/mol and -0.0785 kJ/molK respectively.EDTA was the best eluent for the desorption of Pb(II) ions from the crosslinked chitosan-claybeads. Scanning electron microscope (SEM) was used to characterize the surface morphologyof the crosslinked chitosan-clay beads. © 2012 Elsevier Inc.Item Determination of vitamin e isomers of grape seeds by high-performance liquid chromatography-UV detection(2012) Şeker M.E.; Çelik A.; Dost K.A simple analytical method for the determination of vitamin E isomers in grape seeds by reversed-phase high-performance liquid chromatography with UV detection is described. The method is based on a solidliquid extraction separation on an ODS column, and the analytes are monitored at 295 nm with a UV detector. Tocopherols are extracted in n-hexane and directly injected onto the column without using any purification step, such as saponification, prior to the separation and determination. The chromatographic separation of tocopherols is achieved in 12 min with a mobile phase that consists of n-hexane and isopropyl alcohol (99.99:0.01, v/v). The method is reproducible and accurate, with respect to demonstrating a relative standard deviation between 2.57 and 3.30 (n=10, for 500 ng/mL) and a relative error between 0.84 and 6.54 (n=10, for 500 ng/mL), respectively. The theoretical limits are estimated as 25 ng/mL for α-tocopherol, 43 ng/mL for γ-tocopherol, and 83 ng/mL for δ-tocopherols. The method is then applied for the determination of tocopherols in grape seeds grown in Turkey. The amounts of tocopherols are calculated by using the standard addition method. © 2012 The Author.Item Removal of lead (II) ions from aqueous solution by using crosslinked chitosan-clay beads(Taylor and Francis Inc., 2012) Tirtom V.N.; Dinçer A.; Becerik S.; Aydemir T.; Çelik A.A simple and effective biodegradable material known as chitosan-clay composite beads were prepared to remove Pb(II) ions from aqueous solution. For this purpose, various important parameters such as contact time, pH and temperature were examined on the adsorption of Pb(II) ions onto crosslinked chitosan-clay composite beads. Maximum adsorption capacity of Pb(II) was observed at pH 4.5 and 25°C and calculated as 7.93 mg/g according to Langmuir isotherm model. Thermodynamic parameters namely ΔG°, ΔH° and ΔS° of the Pb(II) adsorption process have been calculated as 7.889 kJ/mol, -15.131 kJ/mol and -0.0785 kJ/molK respectively. EDTA was the best eluent for the desorption of Pb(II) ions from the crosslinked chitosan-clay beads. Scanning electron microscope (SEM) was used to characterize the surface morphology of the crosslinked chitosan-clay beads. © 2012 Desalination Publications.Item Epichlorohydrin crosslinked chitosan-clay composite beads for on-line preconcentration and determination of chromium(iii) by flow injection flame atomic absorption spectrometry(Royal Society of Chemistry, 2014) Cittan M.; Tirtom V.N.; Dinçer A.; Çelik A.An on-line flow injection preconcentration-flame atomic absorption spectrometry (FI-AAS) method is developed for trace determination of chromium(iii) by sorption on a mini-column packed with epichlorohydrin (ECH) crosslinked chitosan-clay composite beads. The factors affecting preconcentration of Cr(iii) ions such as sample and eluent flow rate, loading time, sample and eluent pH, and eluent type and concentration were investigated. The Cr(iii) ions were eluted from the mini-column with 0.1 M EDTA. Under the optimized parameters, the calibration graph using the preconcentration system for Cr(iii) was linear with a correlation coefficient of 0.9982. Detection and quantification limits of the method were obtained to be 0.0162 and 0.0929 μg mL-1 respectively, with an enrichment factor of 13.4. © 2014 The Royal Society of Chemistry.Item Untitled(Turkiye Klinikleri Journal of Medical Sciences, 2016) Karabay O.; Hoşoğlu S.; Güçlü E.; Akalin Ş.; Altay F.A.; Aydin E.; Ceylan B.; Çelik A.; Çelik İ.; Demirdal T.; Demirli K.; Erben N.; Erkorkmaz Ü.; Erol S.; Evirgen Ö.; Gönen İ.; Güner A.E.; Güven T.; Kadanali A.; Koçoğlu M.E.; Kökoğlu Ö.F.; Küçükbayrak A.; Sargin F.; Sünnetçioğlu M.; Şenol Ş.; Taşbakan M.I.; Tekin R.; Turhan V.; Yilmaz G.; Dede B.Background/aim: Broad-spectrum antibiotics have become available for use only with the approval of infectious disease specialists (IDSs) since 2003 in Turkey. This study aimed to analyze the tendencies of doctors who are not disease specialists (non-IDSs) towards the restriction of antibiotics. Materials and methods: A questionnaire form was prepared, which included a total of 22 questions about the impact of antibiotic restriction (AR) policy, the role of IDSs in the restriction, and the perception of this change in antibiotic consumption. The questionnaire was completed by each participating physician. Results: A total of 1906 specialists from 20 cities in Turkey participated in the study. Of those who participated, 1271 (67.5%) had ≤5 years of occupational experience (junior specialists = JSs) and 942 (49.4%) of them were physicians. Specialists having >5 years of occupational experience in their branch expressed that they followed the antibiotic guidelines more strictly than the JSs (P < 0.05) and 755 of physicians (88%) and 720 of surgeons (84.6%) thought that the AR policy was necessary and useful (P < 0.05). Conclusion: This study indicated that the AR policy was supported by most of the specialists. Physicians supported this restriction policy more so than surgeons did. © TÜBITAK.Item Determination of oleuropein using multiwalled carbon nanotube modified glassy carbon electrode by adsorptive stripping square wave voltammetry(Elsevier B.V., 2016) Cittan M.; Koçak S.; Çelik A.; Dost K.A multi-walled carbon nanotube modified glassy carbon electrode was used to prepare an electrochemical sensing platform for the determination of oleuropein. Results showed that, the accumulation of oleuropein on the prepared electrode takes place with the adsorption process. Electrochemical behavior of oleuropein was studied by using cyclic voltammetry. Compared to the bare GCE, the oxidation peak current of oleuropein increased about 340 times at MWCNT/GCE. Voltammetric determination of oleuropein on the surface of prepared electrode was studied using square wave voltammetry where the oxidation peak current of oleuropein was measured as an analytical signal. A calibration curve of oleuropein was performed between 0.01 and 0.70 μM and a good linearity was obtained with a correlation coefficient of 0.9984. Detection and quantification limits of the method were obtained as 2.73 and 9.09 nM, respectively. In addition, intra-day and inter-day precision studies indicated that the voltammetric method was sufficiently repeatable. Finally, the proposed electrochemical sensor was successfully applied to the determination of oleuropein in an olive leaf extract. Microwave-assisted extraction of oleuropein had good recovery values between 92% and 98%. The results obtained with the proposed electrochemical sensor were compared with liquid chromatography-tandem mass spectrometry (LC-MS/MS) analysis. © 2016 Elsevier B.V.Item Characterization of β-glucosidase immobilized on chitosan-multiwalled carbon nanotubes (MWCNTS) and their application on tea extracts for aroma enhancement(Elsevier B.V., 2016) Çelik A.; Dinçer A.; Aydemir T.β-Glucosidase was covalently immobilized on chitosan-MWCNTs carrier and its aroma enhancement effect in different tea samples was investigated. Chitosan-MWCNTs carrier was prepared by mixing chitosan with MWCNTs (5:1 w/w) and characterization of prepared composite carrier was done by FTIR, TGA and SEM analysis. β-Glucosidase was covalently immobilized on the composite carrier after glutaraldeyde activation. After optimization of the immobilization conditions, immobilization yield was achieved as 95.22%. Optimum pH was found as pH 6.0 and pH 5.0 for free and immobilized enzyme, respectively. Optimum temperature of the enzyme was shifted from 35 °C to 45 °C after immobilization. The Km and Vmax values for immobilized β-glucosidase calculated as 5.55 mM and 7.14 U/mg protein respectively. Immobilized β-glucosidase showed better pH and storage stability than free enzyme. After storage at +4 °C for 50 days, the immobilized enzyme retained its 68.4% of the initial activity. The calculated half-life (t1/2) of immobilized enzyme was 115.8 min. After 10 cycles of reuse, immobilized β-glucosidase showed 72.83% of its initial activity. © 2016 Elsevier B.V.Item The effect of 8-week different-intensity walking exercises on serum hepcidin, IL-6, and iron metabolism in pre-menopausal women(Akademiai Kiado ZRt., 2017) Buyukyazi G.; Ulman C.; Çelik A.; Çetinkaya C.; Sisman A.R.; Çimrin D.; Dogru Y.; Kaya D.Objective: Hepcidin may be an important mediator in exercise-induced iron deficiency. Despite the studies investigating acute exercise effects on hepcidin and markers of iron metabolism, we found no studies examining the chronic effects of walking exercises (WE) on hepcidin and markers of iron metabolism in premenopausal women. The chronic effects of two 8-week different-intensity WE on hepcidin, interleukin 6 (IL-6), and markers of iron metabolism in pre-menopausal women were examined. Methods: Exercise groups (EG) [moderate tempo walking group (MTWG), n = 11; brisk walking group (BWG), n = 11] walked 3 days/week, starting from 30 to 51 min. Control group (CG; n = 8) did not perform any exercises. BWG walked at ∼70%-75%; MTWG at ∼50%-55% of HRRmax. VO2max, hepcidin, IL-6, and iron metabolism markers were determined before and after the intervention. Results: VO2max increased in both EGs, favoring the BWG. Hepcidin increased in the BWG (p < 0.01) and CG (p < 0.05). IL-6 decreased in the BWG and the MTWG (p < 0.05; p < 0.01). While iron, ferritin, transferrin, and transferrin saturation levels did not change in any group, total iron binding capacity (p < 0.05), red blood cells (p < 0.05), and hematocrit (p < 0.01) increased only in the BWG. Conclusion: Both WE types may be useful to prevent inflammation. However, brisk walking is advisable due to the positive changes in VO2max and some iron metabolism parameters, which may contribute to prevent iron deficiency. The increase in hepcidin levels remains unclear and necessitates further studies. © 2017 Akadémiai Kiadó, Budapest.Item Removal of arsenic(III) ions from aqueous solutions by modified hazelnut shell(Desalination Publications, 2017) Sert S.; Çelik A.; Tirtom V.N.In this study, modified hazelnut shells (HS) were used to remove As(III) ions from aqueous solutions. For this purpose, FeCl3 and FeCl3 + NaOH were used as modifying agents. Several important parameters influencing the adsorption of As(III) ions such as contact time, pH, temperature and initial metal concentration were investigated following batch experiments. From the results, it is indicated that temperature 20°C and solution pH = 9.0 are the optimum conditions for adsorption. Maximum adsorption experimental capacities of HS that was treated with FeCl3 and FeCl3 + NaOH were 4.37 and 11.84 mg g-1 for arsenic, respectively. The adsorption data at optimum conditions were analyzed by Freundlich, Langmuir, Dubinin-Radushkevich and Temkin isotherm models, and it was found that Freundlich isotherm model gives better fit. Thermodynamic parameters such as enthalpy change (ΔH°), entropy change (ΔS°) and free energy change (ΔG°) were also calculated. These results were indicated that the adsorption of arsenic on HS is exothermic and proceeds spontaneously. Additionally, it can be said that these adsorptions are physical because the Gibbs free energy change (ΔG°) for both adsorbents were found lower than 20 kJ mol-1. © 2017 Desalination Publications. All rights reserved.Item Development and validation of an analytical methodology based on liquid chromatography-electrospray tandem mass spectrometry for the simultaneous determination of phenolic compounds in olive leaf extract(Oxford University Press, 2018) Cittan M.; Çelik A.A simple method was validated for the analysis of 31 phenolic compounds using liquid chromatography- electrospray tandem mass spectrometry. Proposed method was successfully applied to the determination of phenolic compounds in an olive leaf extract and 24 compounds were analyzed quantitatively. Olive biophenols were extracted from olive leaves by using microwave-assisted extraction with acceptable recovery values between 78.1 and 108.7%. Good linearities were obtained with correlation coefficients over 0.9916 from calibration curves of the phenolic compounds. The limits of quantifications were from 0.14 to 3.2 μgg-1. Intra-day and inter-day precision studies indicated that the proposed method was repeatable. As a result, it was confirmed that the proposed method was highly reliable for determination of the phenolic species in olive leaf extracts. © The Author(s) 2017.Item Evaluation of antioxidant capacities and phenolic profiles in Tilia cordata fruit extracts: A comparative study to determine the efficiency of traditional hot water infusion method(Elsevier B.V., 2018) Cittan M.; Altuntaş E.; Çelik A.Herbal infusions are a common practice among people. Making a hot water infusion is the simplest way to extract the medicinal properties of a plant. One of the most frequently used plants for this purpose is linden. Antioxidants (especially phenolic compounds) may also enhance the immune system and reduce the risk of cancer and infections such as colds, a frequent medicinal use for this species. In this work, ultrasound-assisted extraction (UAE) method and infusion extraction (IE) technique using only water as the extractant were carried out comparatively for the extraction of phenolic compounds from Tilia cordata fruits to evaluate the efficiency of the hot water infusion technique. Both extracts obtained with IE and UAE techniques were initially screened for their total phenolic contents (TPCs) and total antioxidant capacities (TACs) via Folin-Ciocalteu and CUPRAC methods, respectively. TPCs of the extracts obtained with IE and UAE were found as 58.86 ± 21.51 and 111.84 ± 13.99 mg gallic acid equivalent (GAE)/g dry sample, respectively. Furthermore, TACs of the extracts obtained with IE and UAE were calculated as 82.99 ± 13.13 and 197.52 ± 12.69 mg trolox equivalent (TE)/g dry sample, respectively. Subsequently, 31 phenolic compounds in the same extracts were scanned by liquid chromatography-electrospray tandem mass spectrometry (LC–MS/MS) method. Among phenolics, 24 compounds were quantitatively determined with protocatechuic acid as the dominant one (1723.1–2183.5 μg/g dry sample). Consequently, the traditional hot water infusion which can be easily applied at home was considered to be a comparatively effective method for the extraction of phenolic compounds from Tilia cordata fruits. © 2018 Elsevier B.V.